US20160126361A1

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Publication number: US20160126361A1
Application number: US14/738,244
Authority: US
Inventors: Zhiqiang Zhao; Ye Tian; Handong PENG; Shuping KANG; Zhanfeng Jiang; Long He
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2014-10-31
Filing date: 2015-06-12
Publication date: 2016-05-05
Also published as: US10069019B2; US20160126373A1; US20160126364A1; US20160126389A1; US20160126372A1; US20160126365A1; US20160126388A1; US20160126362A1; US20190051764A9; US10381493B2; US20160126363A1; US20160126366A1; US10193003B2; US10529868B2; US20160126390A1

Abstract

A solar cell module comprises an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array comprising multiple cells, adjacent cells connected by a plurality of conductive wires, at least two conductive wires comprising the metal wire which extends reciprocally between surfaces of adjacent cells, the conductive wires being in contact with the cells, the front adhesive layer in direct contact with the conductive wires and filling between adjacent conductive wires.

Description

The present application claims priority to the following 41 Chinese applications, the entireties of all of which are hereby incorporated by reference.

The present application is relevant to the following 10 U.S. applications, filed concurrently with the present application, the entireties of which are hereby incorporated by reference.

FIELD

The present disclosure relates to the field of solar cells, and more particularly, to solar cell modules and manufacturing methods thereof.

BACKGROUND

A solar cell module is one of the most important components of a solar power generation device. Sunlight irradiates to a cell from its front surface and is converted to electricity within the cell. Primary grid lines and secondary grid lines are disposed on the front surface and cover part of the front surface of the cell, and then the part of sunlight irradiating to the primary grid lines and the secondary grid lines cannot be converted into electric energy. Thus, the primary grid lines and the secondary grid lines need to be as fine as possible in order for the solar cell module to receive more sunlight. However, the primary grid lines and the secondary grid lines serve to conduct current, and in terms of resistivity, the finer the primary grid lines and the secondary grid lines are, the smaller the cross section area thereof is, which causes greater loss of electricity due to increased resistivity. Therefore, the primary grid lines and the secondary grid lines must be designed to achieve a balance between light blocking and electric conduction, and to take the cost into consideration.

The current solar cell module mainly has a structure of three primary grid lines, and the primary grid lines are formed by printing silver paste on the surface of the cell and sintering. In such a way, the manufacturing of the primary grid lines is a high cost but mature process.

Generally, the solar cell module utilizes solar cells with three primary grid lines, and the solar cells are arranged in a matrix form, usually in the matrix form of 12×6 or 10×6 (i.e. n=12 or 10). Each row is connected by a bus bar. In this connection mode, the current path is longer, along with greater resistance, which tends to cause insufficient welding, and hence affects the photoelectric conversion efficiency of the solar cell module.

Generally, if there are more primary grid lines of the solar cell, the distance between the secondary grid lines and the primary grid lines will be shorter, along with less resistance of the cells connected in series, and better electricity generation performance. However, when the number of the primary grid lines is increased, the width of the primary grid lines is decreased (otherwise the shaded area is increased to lower the electricity generation efficiency), such that it is more difficult to weld the cells in series. Currently, at most five primary grid lines of the cells connected in series can be welded successfully, but the product of five primary grid lines is not commercialized because the cost performance is lower than the product of three primary grid lines.

The solar cell with multiple primary grid lines (over 10 primary grid lines) can only use the metal wire as the primary grid lines, rather than adopt the primary grid lines sintered by silver paste, due to the limitations of series welding technology.

The selection of material for the metal wire shall take cost, conductivity and weldability into consideration. In common metals, the conductivity of copper is slightly lower than silver but has a much lower cost than silver, so copper is given preference. However, the weldability of copper primary grid lines and silver secondary grid lines is not good at a low temperature, and the welding below 200° C. (too high temperature may damage the cells).

Moreover, the metal wire cannot only serve as the primary grid lines on ordinary cells, but also as the welding strip to connect the ordinary cells. The metal wire bridges two adjacent cells—connecting the front surface of one cell with the back surface of the other cell to constitute a series circuit.

Generally, the solar cell module utilizes solar cells with three primary grid lines, and each row of cells is connected by a bus bar. In this connection mode, the current path is longer, along with greater resistance, which tends to cause insufficient welding, and hence affects the photoelectric conversion efficiency of the solar cell module.

SUMMARY

In one aspect, a solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array comprising multiple cells, adjacent cells connected by a plurality of conductive wires, at least two conductive wires being constituted by the metal wire which extends reciprocally between surfaces of adjacent cells, the conductive wires being in contact with the cells, the front adhesive layer in direct contact with the conductive wires and filling between adjacent conductive wires.

In the solar cell module according to embodiments of the present application, the conductive wires constituted by the metal wire which extends reciprocally replace traditional primary grid lines and welding strips, so as to reduce the cost. The metal wire extends reciprocally to decrease the number of free ends of the metal wire and to save the space for arranging the metal wire, i.e. without being limited by the space. The number of the conductive wires constituted by the metal wire which extends reciprocally may be increased considerably, which is easy to manufacture, and thus is suitable for mass production. The front adhesive layer contacts with the conductive wires directly and fills between the adjacent conductive wires, which can effectively isolate the conductive wires from air and moisture to prevent the conductive wires from oxidation to guarantee the photoelectric conversion efficiency.

In another aspect, a method for manufacturing a solar cell module comprises forming at least two conductive wires by a metal wire which extends reciprocally between surfaces of cells and contacts with the surfaces of the cells, such that the adjacent cells are connected by a plurality of conductive wires to constitute a cell array; superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, such that the front adhesive layer contacts with the conductive wires directly; and a back surface of the cell faces the back adhesive layer, and then laminating them, in which the front adhesive layer fills between adjacent conductive wires, so as to obtain the solar cell module.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following descriptions of embodiments with reference to the drawings, in which:

FIG. 1A is a plan view of a solar cell array according to an embodiment of the present disclosure;

FIG. 1B is a plan view of a solar cell array according to another embodiment of the present disclosure;

FIG. 2A is a transverse sectional view of a solar cell array according to an embodiment of the present disclosure;

FIG. 2B is a transverse sectional view of a solar cell array according to another embodiment of the present disclosure;

FIG. 3A is a longitudinal sectional view of a solar cell array according to embodiments of the present disclosure;

FIG. 3B is a longitudinal sectional view of a solar cell array according to another embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a metal wire for forming a conductive wire according to embodiments of the present disclosure;

FIG. 5 is a plan view of a solar cell array according to another embodiment of the present disclosure;

FIG. 6 is a plan view of a solar cell array according to another embodiment of the present disclosure;

FIG. 7 is a schematic diagram of a metal wire extending reciprocally according to embodiments of the present disclosure;

FIG. 8 is a schematic diagram of two cells of a solar cell array according to embodiments of the present disclosure;

FIG. 9 is a sectional view of a solar cell array formed by connecting, by a metal wire, the two cells according toFIG. 8;

FIG. 10 is a schematic diagram of a solar cell module according to embodiments of the present disclosure;

FIG. 11 is a sectional view of part of the solar cell module according toFIG. 10;

FIG. 12A is a schematic diagram of a solar cell array according to another embodiment of the present disclosure;

FIG. 12B is a schematic diagram of a solar cell array according to yet another embodiment of the present disclosure;

FIG. 13 is a schematic diagram of a metal wire under a strain in Comparison Example 1;

FIG. 14 is a curve graph of relationship between the number of conductive wires and photoelectric conversion efficiency in a solar cell array according to embodiments of the present disclosure;

FIG. 15 is a schematic diagram of a solar cell array formed with two cells connected by a metal wire according to an embodiment of the present disclosure.

FIG. 16 is schematic diagram of the solar cell array shown inFIG. 13 after the metal wire is cut.

FIG. 17 is s a schematic diagram of a solar cell array formed with two cells connected by a metal wire according to another embodiment of the present disclosure.

FIG. 18 is a schematic diagram of the solar cell array shown inFIG. 15 after the metal wire is cut.


Reference numerals:

	100	cell module
	10	upper cover plate
	20	frontadhesive layer
	30	cell array
	31	cell
	31A	first cell
	31B	second cell
	311	cell substrate
	312	secondary grid line
	312A	frontsecondary grid line
	312B	backsecondary grid line
	313	backelectric field
	314	back electrode
	32(32C)	conductive wire
	32A	frontconductive wire
	32B	backconductive wire
	321	metal wire body
	322	connection material layer
	33	short grid line
	34	clip
	40	backadhesive layer
	50	lower cover plate

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail and examples of the embodiments will be illustrated in the drawings, where same or similar reference numerals are used to indicate same or similar members or members with same or similar functions. The embodiments described herein with reference to the drawings are explanatory, which are used to illustrate the present disclosure, but shall not be construed to limit the present disclosure.

In prior art, the primary grid lines and the secondary grid lines of the solar cells are made of expensive silver paste, which requires a complicated and costly manufacturing process of the primary grid lines and the secondary grid lines. When the cells are connected into a module, the primary grid lines on the front surface of a cell are welded to the back electrodes of another adjacent cell by a solder strip. Consequently, the welding of the primary grid lines is complicated, and the manufacturing cost of the cells is high.

In prior art, two primary grid lines are usually disposed on the front surface of the cell, and formed by applying silver paste to the front surface of the cell. The primary grid lines have a great width (for example, up to over 2 mm), which consumes a large amount of silver, and makes the cost high.

In prior art, a solar cell with three primary grid lines is provided, but still consumes a large amount of silver, and has a high cost. Moreover, three primary grid lines increase the shaded area, which lowers the photoelectric conversion efficiency.

In addition, the number of the primary grid lines is limited by the solder strip. The larger the number of the primary grid lines is, the finer a single primary grid line is, and hence the solder strip needs to be narrower. Therefore, it is more difficult to weld the primary grid lines with the solder strip and to produce the narrower solder strip, and thus the cost of the welding rises.

Consequently, from the perspective of lowering the cost and reducing the shaded area, in prior art, the silver primary grid lines printed on the cell are replaced with metal wires, for example, copper wires. The copper wires are welded with the secondary grid lines to output the current. Since the silver primary grid lines are no longer used, the cost can be reduced considerably. The copper wire has a smaller diameter to reduce the shaded area, so the number of the copper wires can be raised up to 10. This kind of cell may be called a cell without primary grid lines, in which the metal wire replaces the silver primary grid lines and solder strips in the traditional solar cells.

In prior art, there is a technical solution that the electrical connection of the metal wire and the cells is formed by laminating a transparent film pasted with metal wires and the cells, i.e. multiple parallel metal wires being fixed on the transparent film by adhesion, then being stuck on the cell, and finally being laminated to contact with the secondary grid lines on the cell. In other words, the metal wires are in contact with the secondary grid lines by the laminating process, so as to output the current. However, in this technical solution, the transparent film weakens the absorption rate of light, and a plurality of parallel metal wires may be in bad connection with the cells, which may affect the electrical performance. Thus, the number of the metal wires needs to be increased. If the number of the metal wires is increased, the absorption rate of light from the front surface is affected, and the performance of the product is degraded. Consequently, the product in this technical solution is not promoted and commercialized. Moreover, as said above, the number of the parallel metal wires is limited by the distance between adjacent metal wires.

For example, metal wires may be fixed by a transparent film. Multiple primary grid lines are arranged in parallel, and laminated onto the cells via the transparent film. When the transparent film is laminated with the primary grid lines, the laminating temperature is much lower than the melting temperature of the transparent film, so the transparent film cannot really be laminated with the cells due to the intervals among the primary grid lines, and there will be gap between the transparent film and the cells, so as to cause poor airtightness of the cell module. Moreover, the photoelectric conversion efficiency of the cells will be greatly influenced due to oxidation of air and moisture.

Thus, in the field of solar cells, the structure of the solar cell is uncomplicated, but each component is crucial. The production of the primary grid lines takes various aspects into consideration, such as shaded area, electric conductivity, equipment, process, cost, etc., and hence becomes a difficult and crucial issue in the solar cell technology. In the market, a solar cell with two primary grid lines is replaced with a solar cell with three primary grid lines in 2007 through huge efforts of those skilled in the art. A few factories came up with a solar cell with four primary grid lines around 2014. The concept of multiple primary grid lines is put forward in the recent years, but still there is no relatively mature product.

After extensive research, the inventors of the present disclosure finds if a cell is manufacture in a way that multiple parallel metal wires are drawn simultaneously, cut off, and then welded to the cell simultaneously, due to limitations of sophistication of equipment and process, for example, the influence of stress, the solar cell is bent to some extent when disposed at a free state, so the metal wire needs to remain strained to flatten the cell (a test proves that the minimum strain is at least 2 N for a copper wire with a diameter of 0.2 mm). In order to keep the strain, each metal wire needs to be provided with clips or similar equipment at the two ends thereof, and the equipment occupies certain space, but the space in the cell is limited. Thus, in prior art, at most ten metal wires can be drawn, fixed and welded to a single cell, and it will be difficult to increase the number of the metal wires. The larger the number of the metal wires is, the more free ends there are, such that the equipment needs to control more metal wires at the same time, which is demanding as for the wiredrawing equipment. Moreover, the space of the solar cells is limited. For example, the dimension of a single cell is 156 mm×156 mm. In such limited space, the multiple metal wires need to be controlled accurately at the same time, which is demanding as for the equipment, especially as for the accuracy. Currently, it is still difficult to control and weld multiple metal wires simultaneously in actual production, so the number of the conductive wires is limited, usually at most about ten, which is difficult to realize.

In order to solve the above problem, relevant patents (US20100275976 and US20100043863) provide a technical solution that multiple metal wires are fixed on a transparent film. That's to say, multiple parallel metal wires are fixed on the transparent film by adhesion; then, the transparent film bound with the multiple parallel metal wires is attached to the cell; finally the metal wires contact with the secondary grid lines on the cell by lamination. By this method, the multiple metal wires are fixed via the transparent film, which solves the problem of controlling the multiple metal wires simultaneously, and further increases the number of the metal wires. However, the technical solution almost abandons the welding process. That's to say, the metal wires are not connected with the secondary grid lines by the welding process; instead, the metal wires contact with the secondary grid lines by the laminating process, so as to output the current.

The above technical solution can further increase the number of the metal wires, but the transparent film may affect the light absorption, which causes certain degree of shading, and thus lowers the photoelectric conversion efficiency.

Furthermore, the above technical solution cannot connect the metal wires with the secondary grid lines by the welding process, because the melting temperature of the transparent film must be higher than the welding temperature (usually around 140° C.). Otherwise the transparent film will melt in the process of welding, which may lose the function of fixing the metal wires, and then the metal wires drift, resulting in poor welding effects.

Moreover, it is known to those skilled in the art that the solar cells in use are sealed to prevent moisture and air from penetrating the cells, which may cause corrosion and short circuits. The encapsulating material at present is EVA whose melting point is 70° C. to 80° C., much lower than the welding temperature. If the welding process is employed, as said above, the melting temperature of the transparent film must be higher than the welding temperature, which is higher than the melting point of the encapsulating material. Thus, in the encapsulating process, the encapsulating material (EVA) will melt at the encapsulating temperature, but the transparent film will not, such that the melting encapsulating material cannot penetrate the solid transparent film to completely seal the cells. Hence, the sealing effect is poor, and the actual product tends to fail. In terms of encapsulating, the melting temperature of the transparent film needs to be lower than the welding temperature, which is an evident paradox.

Therefore, the technical solution of fixing the metal wires via the transparent film cannot adopt the welding process to weld the metal wires with the secondary grid lines. The metal wires are merely in contact with the secondary grid lines on the cells, i.e. the metal wires are only placed on the secondary grid lines. Thus, the connection strength of the metal wires and the secondary grid lines is so low that the metal wires tend to separate from the secondary grid lines in the laminating process or in use, which causes bad contact, low efficiency of the cells, or even failure thereof. Consequently, the product in this technical solution is not promoted and commercialized. There is no relatively mature solar cell without primary grid lines.

Especially, the metal wires are relatively fine and in a large number. Moreover, the metal wires are connected afterwards and have free ends. Due to the problem concerning the sophistication of the equipment, it cannot be guaranteed that the fine and many metal wires are connected with the cells in accurate positions, especially the accuracy of the positions of the ends. In order to avoid short circuits caused by the metal wire extending beyond the cells, the conductive wires are generally formed in the cells, in which case part of the secondary grid lines at the edges of the cells cannot be connected with the conductive wires well, thereby resulting in current loss.

The present disclosure seeks to solve at least one of the problems existing in the related art to at least some extent.

The present disclosure provides a solar cell without primary grid lines, which needs neither primary grid line nor sold strip disposed on the cells, and thus lowers the cost. The solar cell without primary grid lines can be commercialized for mass production, easy to manufacture with simple equipment, especially in low cost, and moreover have high photoelectric conversion efficiency.

According to a first aspect of embodiments of the present disclosure, a solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array comprising a plurality of cells arranged in a matrix form of multiple rows and multiple columns, at least two rows of the cells being connected by a plurality of conductive wires, at least two conductive wires being constituted by a metal wire which extends reciprocally between surfaces of the cells in different rows, the conductive wires contacting with the cells, the front adhesive layer being in direct contact with the conductive wires and filling between adjacent conductive wires.

In the solar cell module according to embodiments of the present disclosure, the conductive wires constituted by the metal wire which extends reciprocally replace traditional primary grid lines and welding strips, so as to reduce the cost. The front adhesive layer is in direct contact with the conductive wires and fills between adjacent conductive wires, so as to separate the conductive wires from air and moisture in the outside world effectively, to avoid the oxidation of the conductive wires and to guarantee the photoelectric conversion efficiency.

According to a second aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: arranging a plurality of cells into a cell array of multiple rows and multiple columns; forming at least two conductive wires by a metal wire which extends reciprocally a surface of a cell in a first row and a surface of a cell in a second row, such that the cells in different rows are connected by the conductive wires; superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, such that the front adhesive layer contacts with the conductive wires directly; and a back surface of the cell faces the back adhesive layer, and laminating them, in which the front adhesive layer fills between adjacent conductive wires, so as to obtain the solar cell module.

According to another embodiment of the present disclosure, it is provided a solar cell without primary grid lines, which needs neither expensive silver primary grid line nor sold strip disposed on the cells, and thus lowers the cost. The solar cell without primary grid lines can be commercialized for mass production, easy to manufacture with simple equipment, especially in low cost, and moreover have high photoelectric conversion efficiency.

According to a third aspect of embodiments of the present disclosure, a solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array comprising multiple cells, adjacent cells connected by a plurality of conductive wires, at least two conductive wires being constituted by the metal wire which extends reciprocally between surfaces of adjacent cells, the conductive wires being in contact with the cells, the front adhesive layer in direct contact with the conductive wires and filling between adjacent conductive wires.

In the solar cell module according to embodiments of the present disclosure, the conductive wires constituted by the metal wire which extends reciprocally replace traditional primary grid lines and welding strips, so as to reduce the cost. The metal wire extends reciprocally to decrease the number of free ends of the metal wire and to save the space for arranging the metal wire, i.e. without being limited by the space. The number of the conductive wires constituted by the metal wire which extends reciprocally may be increased considerably, which is easy to manufacture, and thus is suitable for mass production. The front adhesive layer contacts with the conductive wires directly and fills between the adjacent conductive wires, which can effectively isolate the conductive wires from air and moisture to prevent the conductive wires from oxidation to guarantee the photoelectric conversion efficiency.

According to a fourth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: forming at least two conductive wires by a metal wire which extends reciprocally between surfaces of cells and contacts with the surfaces of the cells, such that the adjacent cells are connected by a plurality of conductive wires to constitute a cell array; superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, such that the front adhesive layer contacts with the conductive wires directly; and a back surface of the cell faces the back adhesive layer, and then laminating them, in which the front adhesive layer fills between adjacent conductive wires, so as to obtain the solar cell module.

According to another embodiment of the present disclosure, it is provided a solar cell without primary grid lines, and the number of the conductive wires disposed the cell can be increased up to 20 or even greater. In the present disclosure, the conductive wires are constituted by a few metal wires which extend reciprocally, so as to reduce the free ends. Consequently, the number of the metal wires is not limited by the space, and more conductive wires may be disposed on the cell to facilitate the welding between the multiple conductive wires and the secondary grid lines on the cell. Meanwhile, in the solar cell without primary grid lines of the present disclosure, the conductive wires and the secondary grid lines are connected by welding, which is reliable and simple to manufacture, and has good sealability and high efficiency. Thus, the solar cells satisfy the practical requirements and may be commercialized for mass production.

Thus, the present disclosure provides a solar cell array that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.

The present disclosure further provides a solar cell module having the above solar cell array. The solar cell module is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.

The present disclosure further provides a method for manufacturing the solar cell module.

According to a fifth aspect of embodiments of the present disclosure, a solar cell array includes a plurality of cells arranged in an n×m matrix form, in which in a row of cells, adjacent cells are connected by a plurality of conductive wires, at least two conductive wires constituted by a metal wire which extends reciprocally between surfaces of adjacent cells; in two adjacent rows of cells, a cell in a a^throw and a cell in a (a+1)^throw are connected by the plurality of conductive wires, and at least two conductive wires are constituted by a metal wire extending reciprocally between a surface of a cell in a a^throw and a surface of a cell in a (a+1)^throw, n representing a column, m representing a row and m−1≧a≧1; a secondary grid line and a short grid line are disposed on a front surface of the cell, and the secondary grid line includes a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line and being connected with the conductive wire or at least one middle secondary grid line. The metal wire is coated with a welding layer by which the metal wire is welded with the middle secondary grid line.

In the solar cell array according to embodiments of the present disclosure, the conductive wires are constituted by the metal wire which extends reciprocally. The conductive wires of this structure extend reciprocally between two adjacent cells in a winding way to form a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. Moreover, the conductive wires are arranged in a winding way to avoid failure of the whole conductive wires when a single primary grid line breaks off or is insufficiently welded, so as to avoid instability of the cells. The conductive wires and the secondary grid lines are welded, such that the conductive wires in the solar cell module will not drift or be insufficiently welded, and the solar cell module obtains relatively high photoelectric conversion efficiency.

Further, the cells in each row are directly connected by the conductive wires, which will use fewer bus bars, and reduces the connection distance, resistance and insufficient welding. The conductive wires are arranged in a winding way to avoid all the problems due to cutting the conductive wires. Moreover, the short grid lines are disposed on part of the secondary grid lines at the edges of the shiny surface of the cell, so as to avoid partial current loss because the conductive wires arranged in the winding way cannot reach the secondary grid lines at the edges of the cell. The primary grid liens are constituted by the metal wire coated with an alloy layer with a low melting point, so as to improve welding performance of the conductive wires with the secondary grid lines and/or back electrodes. The conductive wires in the solar cell module will not drift or be insufficiently welded, and have relatively high photoelectric conversion efficiency.

According to a sixth aspect of embodiments of the present disclosure, the solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array being a solar cell array according to the above embodiments.

According to a seventh aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: forming a plurality of conductive wires by a metal wire which extends reciprocally a surface of a first cell of a plurality of cells and a surface of a second cell thereof, such that the adjacent cells are connected by the plurality of conductive wires to constitute a cell array, wherein the plurality of cells are arranged in an n×m matrix form; in a row of cells, a metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell; in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell in a a^throw and a surface of a cell in a (a+1)^throw to obtain the cell array, n representing a column, m representing a row and m−1≧a≧1, a secondary grid line and a short grid line being disposed on a front surface of the cell, the secondary grid line including a middle secondary grid line intersected with the conductive wire and an edge secondary grid line non-intersected with the conductive wire, the short grid line being connected with the edge secondary grid line, and being connected with the conductive wire or at least one middle secondary grid line, the metal wire being coated with a welding layer by which the metal wire is welded with the middle secondary grid line; superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.

The winding method in the present disclosure facilitates electrical connection of the metal wire with the cell, and the good connection performance is beneficial, especially, to welding of the metal wire with the cell, and can avoid insufficient welding of the conductive wires. The solar cell manufactured has beautiful design and good performance. Moreover, a suitable number of conductive wires can be manufactured, as long as they are strained by two clips, which is independent from space limit. The process is easy to realize with simple equipment, which can be industrialized. The edge secondary grid lines at the edges of the cell which are not intersected with the conductive wires are electrically with the conductive wires, so as to reduce current loss. The short grid lines can be formed by screen printing silver, which is easy to realize and to control with high accuracy. The electric connection of all the fine grid lines and the conductive wires can be guaranteed, which lowers the sophistication and difficulty of the process, and improves the photoelectric conversion efficiency of the cell considerably.

According to another embodiment of the present disclosure, it is further provided a solar cell module having the above solar cell array. The solar cell module is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.

According to an eighth aspect of embodiments of the present disclosure, a solar cell array includes a plurality of cells, adjacent cells connected by a plurality of conductive wires constituted by a metal wire. At least one metal wire extends reciprocally between a surface of a first cell of the adjacent cells and a surface of a second cell thereof, and breaks off at a turn after being connected with the cells.

In the solar cell array according to embodiments of the present disclosure, the conductive wires are constituted by the metal wire which extends reciprocally. The metal wire extends reciprocally between two adjacent cells in a winding way to form a folded shape, and then is welded with the cell. After welding, the above metal wire is cut off at the turns thereof. The conductive wires of this structure are easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array.

In addition, the metal wire breaks off at the turns, which can reduce stress upon the metal wire at the turns, and guarantee the welding effect.

According to a ninth aspect of embodiments of the present disclosure, the solar cell module includes an upper cover plate, a front adhesive layer, a cell array, a back adhesive layer and a back plate superposed in sequence, the cell array being a solar cell array according to the above embodiments.

According to a tenth aspect of embodiments of the present disclosure, a method for manufacturing a solar cell module includes: forming at least two conductive wires by a metal wire which extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell, welding the metal wire with secondary grid lines on the front surface of the cell, such that adjacent cells are connected by the plurality of conductive wires; breaking the metal wire at a turn thereof to obtain a cell array; superposing an upper cover plate, a front adhesive layer, the cell array, a back adhesive layer and a back plate in sequence, in which a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.

The winding method in the present disclosure facilitates electrical connection of the metal wire with the cell, and the good connection performance is beneficial, especially, to welding of the metal wire with the cell, and can avoid insufficient welding of the conductive wires. The solar cell manufactured has beautiful design and good performance. Moreover, a suitable number of conductive wires can be manufactured, as long as they are strained by two clips, which is independent from space limit. The process is easy to realize with simple equipment, which can be industrialized.

Part of technical terms in the present disclosure will be elaborated herein for clarity and convenience of description.

According to one embodiment of the present disclosure, referring toFIGS. 1-18,cell31 includes acell substrate311,secondary grid lines312 disposed on a front surface (the surface on which light is incident) of thecell substrate311, a backelectric field313 disposed on a back surface of thecell substrate311, and backelectrodes314 disposed on the backelectric field313. Thus, thesecondary grid lines312 can be called thesecondary grid lines312 of thecell31, the backelectric field313 called the backelectric field313 of thecell31, and theback electrodes314 called theback electrodes314 of thecell31.

Cell substrate

311 can be an intermediate product obtained by subjecting, for example, a silicon chip to processes of felting, diffusing, edge etching and silicon nitride layer depositing. However, it shall be understood that thecell substrate311 in the present disclosure is not limited to be formed by the silicon chip, but includes a thin-film solar cell substrate or any other suitablesolar cell substrate311.

In other words, thecell31 comprises a silicon chip, some processing layers on a surface of the silicon chip, secondary grid lines on a front surface, and a backelectric field313 andback electrodes314 on a back surface, or includes other equivalent solar cells of other types without any front electrode, for instance, various film cells—a-Si film cell, CdTe solar cell, CIGS solar cell, GaAs solar cell, Nano-TiO₂dye-sensitized solar cell (DSSC) etc.

Cell unit includes acell31 andconductive wires32 constituted by a metal wire S.

Asolar cell array30 includes a plurality ofcells31 andconductive wires32 which connectadjacent cells31 and are constituted by the metal wire S. In other words, thesolar cell array30 is formed of a plurality ofcells31 connected by theconductive wires32.

In thesolar cell array30, the metal wire S constitutes theconductive wires32 of the cell unit, and extends between surfaces of theadjacent cells31, which shall be understood in a broad sense that the metal wire S may extend between front surfaces of theadjacent cells31, or may extend between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31. When the metal wire S extends between the front surface of thefirst cell31 and the back surface of thesecond cell31 adjacent to thefirst cell31, theconductive wires32 may include frontconductive wires32A extending on the front surface of thecell31 and electrically connected with thesecondary grid lines312 of thecell31, and backconductive wires32B extending on the back surface of thecell31 and electrically connected with theback electrodes314 of thecell31. Part of the metal wire S between theadjacent cells31 can be called connection conductive wires.

In the present disclosure, thecell substrate311, thecell31, the cell unit, thecell array30 and the solar cell module are only for the convenience of description, and shall not be construed to limit the present disclosure.

All the ranges disclosed in the present disclosure include endpoints, and can be individual or combined. It shall be understood that the endpoints and any value of the ranges are not limited to an accurate range or value, but also include values proximate the ranges or values.

In the present disclosure, orientation terms such as “upper” and “lower” usually refer to the orientation “upper” or “lower” as shown in the drawings under discussion, unless specified otherwise; “front surface” refers to a surface of the solar cell module facing the light when the module is in operation, i.e. a surface on which light is incident, while “back surface” refers to a surface of the solar cell module back to the light when the module is in operation.

In the following, asolar cell module100 according to the embodiments of the present disclosure will be described with respect to the drawings.

As shown inFIG. 1 toFIG. 11, thesolar cell module100 according to the embodiments of the present disclosure includes anupper cover plate10, a frontadhesive layer20, acell array30, a backadhesive layer40 and aback plate50. Thecell array30 includes a plurality ofcells31 which are arranged into a matrix form of multiple rows and multiple columns. At least two rows ofcells31 are connected by a plurality ofconductive wires32, and at least twoconductive wires32 are constituted by a metal wire S which extends reciprocally between surfaces of the cells in different rows. Theconductive wires32 are in contact with thecells31. The frontadhesive layer20 is in direct contact with theconductive wires32 and fills between adjacentconductive wires32.

In the same row of cells,adjacent cells31 are connected by the plurality ofconductive wires32. At least twoconductive wires32 are constituted by the metal wire S which extends reciprocally between surfaces of the adjacent cells. The metal wire S extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31.

Alternatively, as shown inFIG. 1 toFIG. 11, thesolar cell module100 according to the embodiments of the present disclosure includes anupper cover plate10, a frontadhesive layer20, acell array30, a backadhesive layer40 and aback plate50. Thecell array30 includes a plurality ofcells31. Theadjacent cells31 are connected with a plurality ofconductive wires32. At least twoconductive wires32 are constituted by the metal wire S which extends reciprocally between surfaces of adjacent cells. Theconductive wires32 are in contact with thecells31; the frontadhesive layer20 contacts with theconductive wires32 directly and fills between the adjacentconductive wires32.

In other words, thesolar cell module100 according to the embodiments of the present disclosure includes theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 superposed sequentially along a direction from up to down. Thecell array30 includes a plurality ofcells31 andconductive wires32 for connecting the plurality ofcells31. At least twoconductive wires32 are constituted by the metal wire S which extends reciprocally between surfaces of twoadjacent cells31.

Alternatively, as shown inFIG. 1B,FIG. 2B,FIG. 3B andFIG. 12B, thesolar cell array30 according to the embodiments of the present disclosure comprises a plurality ofcells31 arranged in an n×m matrix form. In a row ofcells31, a metal wire extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31 to form a plurality ofconductive wires32, theadjacent cells31 being connected by the plurality ofconductive wires32.

In two adjacent rows ofcells31, the metal wire extends reciprocally between a surface of acell31 in a a^throw and a surface of acell31 in a (a+1)^throw to connect the cells in two adjacent rows, in which n represents a column, m represents a row, and m−1≧a≧1.

The present disclosure is not limited to that multipleconductive wires32 are formed by winding the metal wire—the conductive wires can be partially or completely formed by winding the metal wire. In other words, part of the conductive wires can be formed by non-winded metal wires. The present disclosure aims to reduce free ends, to enlarge operation space. The reciprocal extension can be back and forth once. There is no limit to the termination point of the reciprocal extension—the starting point and the termination point can be at the same cell or at different cells, as long as the metal wire is winded.

Secondary grid lines

312 andshort grid lines33 are disposed on a front surface of thecell31, thesecondary grid lines312 include middlesecondary grid lines3122 intersected with theconductive wires32 and edgesecondary grid lines3121 non-intersected with theconductive wires32; theshort grid lines33 are connected with the edgesecondary grid lines3121, and are connected with theconductive wires32 or at least one middlesecondary grid line3122. The metal wire is coated with a welding layer by which the metal wire is welded with the middlesecondary grid lines3122.

In other words, thesolar cell array30 according to the embodiments of the present disclosure is formed with at least fourcells31 which are arranged in a matrix form of two columns and two rows. Twoadjacent cells31 in the same row are connected by a plurality ofconductive wires32 constituted by the metal wire S which extends reciprocally between twoadjacent cells31. Twoadjacent cells31 in the same column are connected by a plurality ofconductive wires32 constituted by the metal wire S which extends reciprocally between twoadjacent cells31.

Eachcell31 comprises acell substrate311,secondary grid lines312 andshort lines33 disposed on a front surface of thecell substrate311, and backelectrodes314 disposed on a back surface of thecell substrate311.Adjacent cells31 are connected by a plurality ofconductive wires32 constituted by a metal wire S which extends reciprocally between theadjacent cells31.

Thesecondary grid lines312 located at a side surface of thecell substrate311 comprises two parts—one part of thesecondary grid lines312 intersected with theconductive wires32 and located in a middle position of thecell substrate311 to form middlesecondary grid lines3122; the other part of thesecondary grid lines312 non-intersected with theconductive wires32 and located at an edge of one side away from theconductive wires32 to form edgesecondary grid lines3121.

The edgesecondary grid lines3121 are provided withshort grid lines33 connected with theconductive wires32 or at least one middlesecondary grid line3122. Theshort grid lines33 are located at the edges of thecell31 where theconductive wires32 cannot reach when being winded, so as to avoid current loss.

That's to say, eachcell31 is provided withsecondary grid lines312 andshort grid lines33 on the front surface of the cell, and provided withback electrodes314 on the back surface thereof. The two adjacent cells are connected by the plurality ofconductive wires32. Theconductive wires32 are constituted by the metal wire which extends reciprocally between two adjacent cells, and are provided with a welding layer for being welded with the secondary grid lines312. Theconductive wires32 are welded with the secondary grid lines312.

In the solar cell array according to embodiments of the present disclosure, the conductive wires are constituted by the metal wire which extends reciprocally. The conductive wires of this structure extend reciprocally between two adjacent cells in a winding way to form a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. Moreover, the conductive wires are arranged in a winding way to avoid failure of the whole conductive wires when a single primary grid line breaks off or is insufficiently welded, so as to avoid instability of the cells. The conductive wires and the secondary grid lines are welded, such that the conductive wires in the solar cell module will not drift or be insufficiently welded, and the solar cell module obtains relatively high photoelectric conversion efficiency. Further, the cells in each row are directly connected by the conductive wires, which will use fewer bus bars, and reduces the connection distance, resistance and insufficient welding. The conductive wires are arranged in a winding way to avoid all the problems due to cutting the conductive wires. Moreover, the short grid lines are disposed on part of the secondary grid lines at the edges of the shiny surface of the cell, so as to avoid partial current loss because the conductive wires arranged in the winding way cannot reach the secondary grid lines at the edges of the cell. The primary grid liens are constituted by the metal wire coated with an alloy layer with a low melting point, so as to improve welding performance of the conductive wires with the secondary grid lines and/or back electrodes. The conductive wires in the solar cell module will not drift or be insufficiently welded, and have relatively high photoelectric conversion efficiency.

The present disclosure is not limited to that all the conductive wires are formed by winding the metal wire—the conductive wires can be partially or completely formed by winding the metal wire. The reciprocal extension can be back and forth once. There is no limit as to the termination point of the reciprocal extension—the starting point and the termination point can be at the same cell or at different cells, as long as the metal wire is winded.

Specifically, thesolar cell module100 according to the embodiments of the present disclosure includes theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 superposed sequentially along a direction from up to down. Thecell array30 comprises fourcells31 arranged into at least two rows and two columns, in which the twoadjacent cells31 in the same row are connected by the plurality ofconductive wires32 constituted by the metal wire S. The metal wire S extends reciprocally between surfaces of twoadjacent cells31. Theadjacent cells31 in the same column are also connected by the plurality ofconductive wires32 constituted by the metal wire S. The metal wire S extends reciprocally between surfaces of twoadjacent cells31.

Theconductive wires32 are electrically connected with thecells31, in which the frontadhesive layer20 on thecells31 contacts with theconductive wires32 directly and fills between the adjacentconductive wires32, such that the frontadhesive layer20 can fix theconductive wires32, and separate theconductive wires32 from air and moisture from the outside world, so as to prevent theconductive wires32 from oxidation and to guarantee the photoelectric conversion efficiency.

Thus, in thesolar cell module100 according to embodiments of the present disclosure, theconductive wires32 constituted by the metal wire S which extends reciprocally replace traditional primary grid lines and solder strips, so as to reduce the cost. The metal wire S extends reciprocally to decrease the number of free ends of the metal wire S and to save the space for arranging the metal wire S, i.e. without being limited by the space. The number of theconductive wires32 constituted by the metal wire which extends reciprocally may be increased considerably, which is easy to manufacture, and thus is suitable for mass production. The frontadhesive layer20 contacts with theconductive wires32 directly and fills between the adjacentconductive wires32, which can effectively isolate the conductive wires from air and moisture to prevent theconductive wires32 from oxidation to guarantee the photoelectric conversion efficiency.

The frontadhesive layer20 and the backadhesive layer40 are adhesive layers commonly used in the art. Preferably, the frontadhesive layer20 and the backadhesive layer40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA). In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.

In the embodiments of the present disclosure, theupper cover plate10 and theback plate50 can be selected and determined by conventional technical means in the art. Preferably, theupper cover plate10 and theback plate50 can be transparent plates respectively, for example, glass plates.

In the process of manufacturing thesolar cell module100, the conductive wires can be first bound or welded with the secondary grid lines and the conductive adhesive of the back electrodes of thecell31, and then superposed and laminated.

Other components of thesolar cell module100 according to the present disclosure are known in the art, which will be not described in detail herein.

In the following, asolar cell array30 according to the embodiments of the present disclosure will be described with respect to the drawings.

Specifically, thesolar cell array30 according to the embodiments of the present disclosure includes a plurality ofcells31 which are arranged into a matrix form of multiple rows and multiple columns. At least two rows ofcells31 are connected by a metal wire S which extends reciprocally between surfaces of the cells in different rows and constitutesconductive wires32.

Alternatively, thesolar cell array30 according to the embodiments of the present disclosure includes a plurality ofcells31. Theadjacent cells31 are connected with a plurality ofconductive wires32 which are constituted by a metal wire S. The metal wire S is electrically connected with thecells31 and extends reciprocally between the surfaces of theadjacent cells31.

A cell unit is formed by thecell31 and theconductive wires32 constituted by the metal wire S which extends on the surface of thecell31. In other words, thesolar cell array30 according to the embodiments of the present disclosure is formed with a plurality of cell units; theconductive wires32 of the plurality of cells are formed by the metal wire S which extends reciprocally between the surfaces of thecells31.

It shall be understood that the term “extending reciprocally” in this disclosure can be called “winding” which means that the metal wire S extends between the surfaces of thecells31. For example, referring toFIG. 1, in some circumstances, the metal wire extends between the surfaces of thecells31 in the same plane, such as either between the front surfaces or between the bottom surfaces of the cells, to form a serpentine pattern. In some other circumstances, the metal wire S extends between the surfaces of thecells31 in multiple planes, such as between both the front surface of a cell and the bottom surface of an adjacent cell, to form a serpentine pattern. In yet other circumstances, the metal wire S extends between the surfaces of thecells31 both in the same plane and in multiple planes, such as sometimes between either the front surfaces or the bottom surfaces of some adjacent cells, and at other times between both the front surface of a certain cell and the bottom surface of an adjacent cell, to form a serpentine pattern. The plurality of conductive wires equals two or more passes of the serpentine shaped pattern. Preferably, two or more passes of the serpentine shaped pattern on the same plane are substantially parallel to each other. More preferably, all the passes of the serpentine shaped pattern on the same plane are substantially parallel to each other.

In the present disclosure, it shall be understood in a broad sense that “the metal wire S extends reciprocally between surfaces of thecells31. For example, the metal wire S may extend reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31; the metal wire S may extend from a surface of thefirst cell31 through surfaces of a predetermined number ofmiddle cells31 to a surface of thelast cell31, and then extends back from the surface of thelast cell31 through the surfaces of a predetermined number ofmiddle cells31 to the surface of thefirst cell31, extending reciprocally like this.

In addition, when thecells31 are connected in parallel by the metal wire S, the metal wire S can extend on front surfaces of thecells31, such that the metal wire S constitutes frontconductive wires32A. Alternatively, a first metal wire S extends reciprocally between the front surfaces of thecells31, and a second metal wire S extends reciprocally between the back surfaces of thecells31, such that the first metal wire S constitutes frontconductive wires32A, and the second metal wire S constitutes backconductive wires32B.

When thecells31 are connected in series by the metal wire S, the metal wire S can extend reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31, such that part of the metal wire S which extends on the front surface of thefirst cell31 constitutes frontconductive wires32A, and part thereof which extends on the back surface of thesecond cell31 constitutes backconductive wires32B. In the present disclosure, unless specified otherwise, theconductive wires32 can be understood as the frontconductive wires32A, the backconductive wires32B, or the combination thereof.

The term “extending reciprocally” can be understood as that the metal wire S extends reciprocally once to form twoconductive wires32 which are formed by winding a metal wire S. For example, two adjacent conductive wires form a U-shape structure or a V-shape structure, yet the present disclosure is not limited to the above.

In thesolar cell array30 according to the embodiments of the present disclosure, theconductive wires32 of the plurality ofcells31 are constituted by the metal wire S which extends reciprocally; and theadjacent cells31 are connected by theconductive wires32. Hence, the cells are not necessarily printed with expensive silver primary gird lines on the surfaces thereof, and can be manufactured in a simple manner without using a solder strip to connect the cells. It is convenient to connect the metal wire S with the secondary grid lines and the back electrodes, so that the cost of the cells is reduced considerably.

Moreover, since theconductive wires32 are constituted by the metal wire S which extends reciprocally, the width of the conductive wires32 (i.e. the width of projection of the metal wire on the cell) may be decreased, thereby decreasing the shaded area of the front surface. Further, the number of theconductive wires32 can be adjusted easily, and thus the resistance of theconductive wires32 is reduced, compared with the primary grid lines made of the silver paste, and the photoelectric conversion efficiency is improved. Since the metal wire S extends reciprocally to form the conductive wires, when thecell array30 is used to manufacture thesolar cell module100, the metal wire S will not tend to shift, i.e. the metal wire is not easy to “drift”, which will not affect but further improve the photoelectric conversion efficiency.

Therefore, thesolar cell array30 according to the embodiments of the present disclosure has low cost and high photoelectric conversion efficiency.

In some specific embodiments of the present disclosure, in the same row ofcells31, the metal wire S extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31.

Alternatively, in the present disclosure, the metal wire S extends reciprocally between a front surface of thefirst cell31 and a back surface of thesecond cell31 adjacent to thefirst cell31. The frontadhesive layer20 directly contacts with theconductive wires32 on the front surface of thefirst cell31 and fills between the adjacentconductive wires32 on the front surface of thefirst cell31. The backadhesive layer40 directly contacts with theconductive wires32 on the back surface of thesecond cell31 and fills between the adjacentconductive wires32 on the back surface of thesecond cell31.

In other words, in the present disclosure, the twoadjacent cells31 are connected by the metal wire S. In the twoadjacent cells31, the front surface of thefirst cell31 is connected with the metal wire S, and the back surface of thesecond cell31 is connected with the metal wire S.

The frontadhesive layer20 on thefirst cell31 whose front surface is connected with the metal wire S is in direct contact with the metal wire S on the front surface of thefirst cell31 and fills between the adjacentconductive wires32. The backadhesive layer40 on thesecond cell31 whose back surface is connected with the metal wire S is in direct contact with the metal wire S on the back surface of thesecond cell31 and fills between the adjacent conductive wires32 (as shown inFIG. 2).

Consequently, in thesolar cell module100 according to the present disclosure, not only the frontadhesive layer20 can separate theconductive wires32 on the front surfaces of part of thecells31 from the outside world, but also the backadhesive layer40 can separate theconductive wires32 on the back surfaces of part of thecells31 from the outside world, so as to further guarantee the photoelectric conversion efficiency of thesolar cell module100.

Alternatively, theconductive wires32 located on the back surface of thesecond cell31 are electrically connected with theback electrodes314 of thesecond cell31.

That's to say, the metal wire S extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31. The metal wire S forms frontconductive wires32A on the front surface of thefirst cell31, and forms backconductive wires32B on the back surface of thesecond cell31. The backconductive wires32B located on the back surface of thesecond cell31 are electrically connected with theback electrodes314 of thesecond cell31, so as to guarantee the effect of connecting the metal wire S and thesecond cell31.

In the following, thesolar cell array30 according to specific embodiments of the present disclosure will be described with reference to the drawings.

Thesolar cell array30 according to a specific embodiment of the present disclosure is illustrated with reference toFIG. 1 toFIG. 3.

In the embodiment shown inFIG. 1 toFIG. 3, twocells31 in thesolar cell array30 are shown. In other words, it shows twocells31 connected with each other via theconductive wires32 constituted by the metal wire S.

It can be understood that thecell31 comprises acell substrate311, secondary grid lines312 (i.e. frontsecondary grid lines312A) disposed on a front surface of thecell substrate311, a backelectric field313 disposed on a back surface of thecell substrate311, and backelectrodes314 disposed on the backelectric field313. In the present disclosure, it shall be understood that theback electrodes314 may be back electrodes of a traditional cell, for example, printed by the silver paste, or may be backsecondary grid lines312B similar to the secondary grid lines on the front surface of the cell substrate, or may be multiple discrete welding portions, unless specified otherwise. The secondary grid lines refer to thesecondary grid lines312 on the front surface of thecell substrate311, unless specified otherwise.

As shown inFIG. 1 toFIG. 3, the solar cell array in the embodiment includes two cells (called afirst cell31A and asecond cell31B respectively for convenience of description). The metal wire S extends reciprocally between the front surface of thefirst cell31A (a shiny surface, i.e. an upper surface inFIG. 2) and the back surface of thesecond cell31B, such that the metal wire S constitutes front conductive wires of thefirst cell31A and back conductive wires of thesecond cell31B. The metal wire S is electrically connected with the secondary grid lines of thefirst cell31A (for example, being welded or bound by a conductive adhesive), and electrically connected with the back electrodes of thesecond cell31B.

In some embodiments, the metal wire extends reciprocally between thefirst cell31A and thesecond cell31B for 10 to 60 times to form 20 to 120 conductive wires. Preferably, as shown inFIG. 1, the metal wire extends reciprocally for 12 times to form 24conductive wires32, and there is only one metal wire. In other words, a single metal wire extends reciprocally for 12 times to form 24 conductive wires, and the distance of the adjacent conductive wires can range from 2.5 mm to 15 mm. In this embodiment, the number of the conductive wires is increased, compared with the traditional cell, such that the distance between the secondary grid lines and the conductive wires which the current runs through is decreased, so as to reduce the resistance and improve the photoelectric conversion efficiency. In the embodiment shown inFIG. 1, the adjacent conductive wires form a U-shape structure, for convenience of winding the metal wire. Alternatively, the present disclosure is not limited to the above. For example, the adjacent conductive wires can form a V-shape structure.

As shown inFIG. 14, it shows the relationship between the number of the conductive wires and the photoelectric conversion efficiency of the cell module. It can be seen fromFIG. 14 that the photoelectric conversion efficiency of the cell module is relatively high when the number of theconductive wires32 ranges from 20 to 30.

More preferably, as shown inFIG. 4, the metal wire S includes ametal wire body321 and aconnection material layer322 coating the outer surface of the metal wire body, and theconnection material layer322 can be a conductive adhesive layer or a welding layer. The metal wire is welded with the secondary grid lines and/or the back electrodes by the welding layer, such that it is convenient to electrically connect the metal with the secondary grid lines and/or the back electrodes, and to avoid drifting of the metal wire in the connection process so as to guarantee the photoelectric conversion efficiency. Of course, the electrical connection of the metal with the cell substrate can be conducted during or before the laminating process of the solar cell module, and preference is given to the latter.

It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on thecells31 to form theconductive wires32; and theconductive wires32 include ametal wire body321 and aconnection material layer322 coating themetal wire body321, i.e. the metal wire S consists of themetal wire body321 and theconnection material layer322 coating themetal wire body321. In the embodiments of the present disclosure, unless specified otherwise, the metal wire represents the metal wire S which extends reciprocally on the cells to form theconductive wires32.

In some embodiments, preferably, themetal wire body321 is a copper wire. Of course, the metal wire S can be a copper wire, too. In other words, the metal wire does not include theconnection material layer322, but the present disclosure does not limited thereto. For example, themetal wire body321 can be an aluminum wire. Preferably, the metal wire S has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.

In some embodiments, preferably, before the metal wire contact the cells, the metal wire extends under a strain, i.e. straightening the metal wire. After the metal wire is connected with the secondary grid lines and the back electrodes of the cell, the strain of the metal wire can be released, so as to further avoid the drifting of the conductive wires when the solar cell module is manufactured, and to guarantee the photoelectric conversion efficiency.

FIG. 5 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure. As shown inFIG. 5, the metal wire extends reciprocally between the front surface of thefirst cell31A and the front surface of thesecond cell31B, such that the metal wire constitutes front conductive wires of thefirst cell31A and front conductive wires of thesecond cell31B. In such a way, thefirst cell31A and thesecond cell31B are connected in parallel. Of course, it can be understood that preferably the back electrodes of thefirst cell31A and the back electrodes of thesecond cell31B can be connected via back conductive wires constituted by another metal wire which extends reciprocally. Alternatively, the back electrodes of thefirst cell31A and the back electrodes of thesecond cell31B can be connected in a traditional manner.

According to an embodiment of the present disclosure, theadjacent cells31 are connected by a plurality ofconductive wires32 constituted by the metal wire which extends between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31.

Alternatively, the metal wire breaks off at a turn after being connected with thecells31.

Preferably, theshort grid lines33 are connected with the edgesecondary grid line3121 closest to the middlesecondary grid lines3122.

In some other specific embodiments of the present disclosure, theshort grid lines33 are connected with theconductive wires32. Preferably, theshort grid lines33 and the metal wire at the front surface of thecell31 are connected at a turn.

According to an embodiment of the present disclosure, theshort grid lines33 are perpendicular to the secondary grid lines312. Theshort grid lines33 are, preferably, electrically connected with bended parts (ends proximate to the edges) of theconductive wires32 on the shiny surface of thecell31. An extra welding point can be added to decrease the probability of breaking the welding portion at the edges, and to further enhance the binding force of the metal wire and the cell. The connection with at the turn herein can be understood that theshort grid lines33 have intersection points with the turns, i.e. theshort grid lines33 do not terminate at the turns. More preferably, at least oneshort grid line33 is disposed corresponding with each bended part. Of course, theshort gird lines33 can be connected with other parts of theconductive wires32, for example, arc segments.

Since the distance between the bended parts of theconductive wires32 and the edges of thecell31 is usually short, theshort grid lines33 have a length of 1 to 10 mm, preferably 2.4 to 7 mm, a width of 0.05 to 0.5 mm, and a thickness of 0.01 to 0.02 mm. There are 3 to 40, preferably 6 to 20 short grid lines.

Theshort grid lines33 can be disposed in the same manner as thesecondary grid lines312 on the shiny surface of thecell31. For example, theshort grid lines33 can be printed along with thesecondary grid lines312 by silk-screen printing at the same screen plate (which can be made of silver paste) as the frontsecondary grid lines3121.

In some preferable embodiments of the present disclosure, thesecondary grid lines312 have a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3 mm.

Alternatively, the metal wire breaks off at a turn after being connected with thecell31. The metal wire breaks off at the turn after being welded with thecell31 to form multiple independentconductive wires32. The metal wire breaks off at the turn after being welded with thecell31 to separate the multipleconductive wires32, which can decrease the stress between the cells and peeling strength at the joints of the metal wire and the cell, and further improve the photoelectric conversion efficiency of thesolar cell array30.

In some specific embodiments of the present disclosure, in a row of thecells31, the adjacent cells are connected by a metal wire that extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to the first cell and constitutes theconductive wire32. Alternatively, a plurality ofcells31 are arranged in an n×m matrix form, and in two adjacent rows ofcells31, the metal wire extends reciprocally between a surface of acell31 in a a^throw and a surface of a cell in a (a+1)^throw, in which n represents a column, m represents a row, and m−1≧a≧1.

Alternatively, in two adjacent rows ofcells31, the metal wire extends reciprocally between a surface of acell31 at an end of the a^throw and a surface of acell31 at an end of the (a+1)^throw, the end of the a^throw and the end of the (a+1)^throw located at the same side of the matrix form.

Preferably, in the same row ofcells31, the metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31. In two adjacent rows ofcells31, the metal wire extends reciprocally between a front surface of acell31 at an end of the a^throw and a back surface of acell31 at an end of the (a+1)^throw, to connect the two adjacent rows ofcells31 in series.

In other words, thesolar cell array30 according to the embodiment of the present disclosure is arranged in an n×m matrix form by a plurality ofcells31. Specifically, in thesolar cell array30, there aremultiple cells31, and the cells are arranged in the n×m matrix form. In a row of cells, theconductive wire32 extends from a surface of afirst cell31, and is electrically connected with a surface of asecond cell31 adjacent to thefirst cell31, to connect thecells31 in the same row; in two adjacent rows of cells, theconductive wire32 extends from a surface of acell31 in a a^throw and is electrically connected with a surface of a cell in a (a+1)^throw, to connect the two adjacent rows ofcells31, in which n represents a column, m represents a row, and m−1≧a≧1.

N can range from 2 to 30, m ranging from 2 to 18. Preferably,multiple cells31 are arranged in a 12×6 or 10×6 matrix form, i.e. 10 or 12 cells in a row, six rows in total. According to the preferable embodiment, thecells31 in two adjacent rows are directly connected by the conductive wires without using the bus bars, which decreases the number of the bus bars, shortens the connection distance, and reduces the resistance, so as to obtain higher electricity generation performance of the solar cell module.

Preferably, in the two adjacent rows ofcells31, the conductive wire extends from a surface of acell31 at an end of a a^throw and is electrically connected with a surface of a cell at an end of a (a+1)^throw.

According to an embodiment of the present disclosure, the solar cell comprises a plurality ofcells31, and theadjacent cells31 are connected by a plurality ofconductive wires32 constituted by a metal wire. At least one metal wire extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31, and breaks off at a turn after being connected with thecells31.

That's to say, in the present application, the metal wire is welded with thecell31 after extending reciprocally between the surface of thefirst cell31 and the surface of thesecond cell31. It is evitable to form turns when the metal wire extends reciprocally between the surface of thefirst cell31 and the surface of thesecond cell31, and the turns are broken after the metal wire is welded with thecell31.

Specifically, in the process of manufacturing thesolar cell array30, the turns of the metal wire are located beyond the edges of thecell31; when the metal wire is welded with thecell31, thewhole cell31 and the corresponding metal wire can be held together by a pressing plate from the upper and lower surfaces respectively.

If the turns of the metal wire are located within the edges of thecell31, two pressing plates are needed in each surface to press thewhole cell31 and the corresponding metal wire, so as to break the wire. Moreover, thecell31 has to be pressed by the pressing plates before and after breaking the wire, i.e. two operations, which is complicated to operate, and results in low efficiency.

In the present application, the metal wire is cut off at the turns, so as to reduce stress upon the metal wire at the turns and to guarantee the welding effect.

It shall be explained that in the present disclosure, the two adjacent conductive wires form straight line segments parallel with each other, or line segments having arcs at ends.

That's to say, in the present disclosure, when the metal wire that extends reciprocally betweenadjacent cells31 breaks off at the turns, it can just simply break off at the turns, in which case theconductive wires32 constituted by the metal wire will have arcs at the ends; the arc segments at the turns can be totally cut off, in which case theconductive wires32 constituted by the metal wire will not have arcs at the ends, and the adjacentconductive wires32 are parallel with each other.

Specifically, as shown inFIG. 13 andFIG. 14, the metal wire inFIG. 13 extends reciprocally between twoadjacent cells31 to form a turn-back structure, in which the metal wire is completely located within the edges of thecell31; when the metal wire is cut off at the turns, thegaps323 are at the ends of the turns of the metal wire. The structure of the metal wire after being cut off at the turns is shown inFIG. 14, and in this way theconductive wires32 constituted by the metal wire will have arcs at the ends.

In another embodiment of the present disclosure, as shown inFIG. 15 andFIG. 16, the metal wire inFIG. 15 extends reciprocally between twoadjacent cells31 to form a turn-back structure, in which the turns of the metal wire are located beyond the edges of thecell31; when the metal wire is cut off at the turns, thegaps323 are located within thecell31. In the process of cutting the metal wire, all the turns of the metal wire are completely cut off. In this way, theconductive wires32 constituted by the metal wire will not have arcs at the ends, and the adjacentconductive wires32 are parallel with each other.

In addition, theconductive wires32 is welded with thesecondary grid lines312 at the front surface of thecell31 by a welding layer which coats the metal wire or is disposed on the secondary grid lines312.

That's to say, thesecondary grid lines312 and theconductive wires32 are welded by a welding layer disposed on thesecondary grid lines312 or coating the metal wire.

According to a preferable embodiment of the present disclosure, a welding layer is disposed at a position where theconductive wires32 are in contact with thesecondary grid lines312 and/or theback electrodes314 of thecell31. More preferably, the welding layer is disposed at the positions where theconductive wires32 are in contact with thesecondary grid lines312 of thecell31 and in contact with theback electrodes314 thereof respectively. The welding layer can be only applied to thesecondary grid lines312 andback electrodes314, or can also be applied to theconductive wires32. The welding layer may be a metal with a lower melting point or an alloy. The tin alloy can be a conventional tin alloy, for example, containing Sn, and at least one of Bi, Pb, Ag and Cu, more specifically, i.e. SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient soldering between theconductive wires32 and thesecondary grid lines312 and/or theback electrodes314 of the cell, and to render the solar cell module higher photoelectric conversion efficiency.

In thecell array30, the ratio of the thickness of the welding layer and the diameter of the metal wire is (0.02-0.5):1.

In the present disclosure, when there is a welding layer disposed at a position where theconductive wires32 are in contact with thesecondary grid lines312 and/or theback electrodes314 of thecell31, theconductive wires32 can be a metal wire. The metal wire may be conventional in the art, for example, a copper wire.

In an embodiment, the conductive wires (including the frontconductive wires32A and backconductive wires32B) include a metal wire and an alloy layer with a low melting point coating the metal wire. The alloy layer may coat the metal wire completely or partially. When the alloy layer coats the metal wire partially, the alloy layer is, preferably, formed at a position where the alloy layer is welded with thesecondary grid lines312 and/or theback electrodes314 of thecell31. When the alloy layer coats the metal wire completely, the alloy layer can coat the periphery of the metal wire in a circular manner. The thickness of the alloy layer can fall into a relatively wide range. Preferably, the alloy layer has a thickness of 1 to 100 μm, more preferably, 1 to 30 μm. The alloy for forming the alloy layer with a low melting point may be a conventional alloy with a low melting point which can be 100 to 200° C. Preferably, the alloy with the low melting point contains Sn, and at least one of Bi, In, Ag, Sb, Pb and Zn, more preferably, containing Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Specifically, the alloy may be at least one of Sn—Bi alloy, In—Sn alloy, Sn—Pb alloy, Sn—Bi—Pb alloy, Sn—Bi—Ag alloy, In—Sn—Cu alloy, Sn—Bi—Cu alloy and Sn—Bi—Zn alloy. Most preferably, the alloy is Bi—Sn—Pb alloy, for example, containing 40 weight percent of Sn, 55 weight percent of Bi, and 5 weight percent of Pb (i.e. Sn40%-Bi55%-Pb5%). The thickness of the alloy layer with the low melting point can be 0.001 to 0.06 mm. Theconductive wire32 may have a cross section of 0.01 to 0.5 mm²The metal wire can be conventional in the art, for example, a copper wire.

In thecell array30, thecell31 can be aconventional cell31 in the art, for example, apolycrystalline silicon cell31. Thesecondary grid lines312 on the shiny surface of thecell31 can be Ag, Cu, Sn, and tin alloy. Thesecondary grid line312 has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3 mm. Theback electrodes314 on the back surface of thecell31 can be made of Ag, Cu, Sn and tin alloys. Theback electrodes314 are usually in a ribbon pattern, and have a width of 1 to 4 mm, and a thickness of 5 to 20 μm.

Thesolar cell array30 according to another embodiment of the present disclosure is illustrated with reference toFIG. 6.

Thesolar cell array30 according to the embodiment of the present disclosure comprises n×mcells31. In other words, a plurality ofcells31 are arranged in an n×m matrix form, n representing a column, and m representing a row. More specifically, in the embodiment, 36cells31 are arranges into six columns and six rows, i.e. n=m=6. It can be understood that the present disclosure is not limited thereto. For example, the column number and the row number can be different. For convenience of description, inFIG. 6, in a direction from left to right, thecells31 in one row are called afirst cell31, asecond cell31, athird cell31, afourth cell31, afifth cell31, and asixth cell31 sequentially; in a direction from up to down, the columns of thecells31 are called a first column ofcells31, a second column ofcells31, a third column ofcells31, a fourth column ofcells31, a fifth column ofcells31, and a sixth column ofcells31 sequentially.

In a row of thecells31, the metal wire extends reciprocally between a surface of afirst cell31 and a surface of asecond cell31 adjacent to thefirst cell31; in two adjacent rows ofcells31, the metal wire extends reciprocally between a surface of acell31 in a a^throw and a surface of acell31 in a (a+1)^throw, and m−1≧a≧1.

As shown inFIG. 6, in a specific example, in a row of thecells31, the metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 adjacent to thefirst cell31, so as to connect thecells31 in one row in series. In two adjacent rows ofcells31, the metal wire extends reciprocally between a front surface of acell31 at an end of the a^throw and a back surface of acell31 at an end of the (a+1)^throw, to connect the two adjacent rows ofcells31 in series.

More preferably, in the two adjacent rows ofcells31, the metal wire extends reciprocally between the surface of thecell31 at an end of the a^throw and the surface of thecell31 at an end of the (a+1)^throw, the end of the a^throw and the end of the (a+1)^throw located at the same side of the matrix form, as shown inFIG. 6, located at the right side thereof.

More specifically, in the embodiment as shown inFIG. 6, in the first row, a first metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31; a second metal wire extends reciprocally between a front surface of thesecond cell31 and a back surface of athird cell31; a third metal wire extends reciprocally between a front surface of thethird cell31 and a back surface of afourth cell31; a fourth metal wire extends reciprocally between a front surface of thefourth cell31 and a back surface of afifth cell31; a fifth metal wire extends reciprocally between a front surface of thefifth cell31 and a back surface of asixth cell31. In such a way, theadjacent cell bodies31 in the first row are connected in series by corresponding metal wires.

As said above, the cell bodies in the embodiments of the present disclosure are connected in series by the conductive wires—the first row, the second row, the third row, the fourth row, the fifth row and the sixth row are connected in series by the conductive wires. As shown in the figures, the metal wire may extend beyond the cell for connection with other loads. For example, alternatively, the second and third row, and the fourth and fifth rows can be connected in parallel with a diode respectively to avoid light spot effect. The diode can be connected in a manner commonly known to those skilled in the art, for example, by a bus bar.

However, the present disclosure is not limited to the above. For example, the first and second rows can be connected in series, the third and fourth rows connected in series, the fifth and sixth rows connected in series, and meanwhile the second and third rows are connected in parallel, the fourth and fifth connected in parallel. In such a case, a bus bar can be disposed at the left or right side of corresponding rows respectively.

Alternatively, thecells31 in the same row can be connected in parallel. For example, a metal wire extends reciprocally from a front surface of afirst cell31 in a first row through the front surfaces of the second to thesixth cells31.

In some specific embodiments of the present disclosure, a binding force between the metal wire and thecells31 ranges from 0.1 N to 0.8 N. That's to say, the binding force between theconductive wires32 and thecells31 ranges from 0.1 N to 0.8 N. Preferably, the binding force between the metal wire and the cells ranges from 0.2 N to 0.6 N, so as to secure the welding between the cells and the metal wire, to avoid sealing-off of the cells in the operation and the transferring process and performance degradation due to poor connection, and to lower the cost.

Thesolar cell module100 according to embodiments of the present disclosure is illustrated with reference toFIG. 10 andFIG. 11.

As shown inFIG. 10 andFIG. 11, thesolar cell module100 according to embodiments of the present disclosure includes anupper cover plate10, a frontadhesive layer20, thecell array30, a backadhesive layer40 and aback plate50 superposed sequentially along a direction from up to down.

In the process of manufacturing thesolar cell module100, the conductive wire can be first bounded or welded with the secondary grid lines and the back electrode of thecell31, and then superposed and laminated.

Specifically, thesolar module100 includes anupper cover plate10, a frontadhesive layer20, thecell array30, a backadhesive layer40 and aback plate50. Thecell array30 includes a plurality ofcells31, andadjacent cells31 are connected by the plurality ofconductive wires32. At least twoconductive wires32 are constituted by the metal wire S which extends reciprocally between surfaces of adjacent cells. Theconductive wires32 are welded with the secondary grid lines. The frontadhesive layer20 contacts with theconductive wires32 directly and fills between the adjacentconductive wires32.

That's to say, thesolar cell module100 according to the present disclosure includes anupper cover plate10, a frontadhesive layer20, thecell array30, a backadhesive layer40 and aback plate50 superposed sequentially along a direction from up to down. Thecell array30 includes a plurality ofcells31 andconductive wires32 for connecting the plurality ofcells31. The conductive wires are constituted by the metal wire S which extends reciprocally between surfaces of twoadjacent cells31.

In some specific embodiments of the present disclosure, the metal wire S extends reciprocally between a front surface of a first cell and a back surface of a second cell adjacent to the first cell; the frontadhesive layer20 contacts with the conductive wires on the front surface of thefirst cell31 directly and fills between the adjacentconductive wires32 on the front surface of thefirst cell31; the backadhesive layer40 contacts with theconductive wires32 on the back surface of thesecond cell31 directly and fills between the adjacentconductive wires32 on the back surface of thesecond cell31.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a series resistance of 380 to 440 mΩ per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. When there are 72 cells, the series resistance of the solar cell module is 456 to 528 mΩ, and the electrical performance of the cells is better.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has an open-circuit voltage of 37.5-38.5 V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The short-circuit current is 8.9 to 9.4 A, and is not related to the number of the cells.

In some specific embodiments of the present disclosure, the solar cell module has a fill factor of 0.79 to 0.82, which is independent from the dimension and number of the cells, and can affect the electrical performance of the cells.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a working voltage of 31.5-32 V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The working current is 8.4 to 8.6 A, and is not related to the number of the cells.

In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a conversion efficiency of 16.5-17.4%, and a power of 265-280 W per 60 cells.

A method for manufacturing thesolar cell module100 according to the embodiments of the present disclosure will be illustrated with respect toFIG. 1 toFIG. 3 andFIG. 7 toFIG. 9.

The method includes: arranging a plurality ofcells31 into acell array30 of multiple rows and multiple columns; forming a plurality ofconductive wires32 by a metal wire which extends reciprocally between a surface of acell31 in a row and a surface of acell31 in another row, to connect the cells in different rows by theconductive wires32; superposing anupper cover plate10, a frontadhesive layer20, thecell array30, a backadhesive layer40 and aback plate50 in sequence, in which a front surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and a back surface of thecell31 faces the backadhesive layer40, and laminating them, in which the frontadhesive layer20 fills between adjacentconductive wires32, so as to obtain thesolar cell module100.

In other words, in the process of manufacturing thesolar cell module100, the plurality ofcells31 are arranged into thecell array30 of multiple rows and multiple columns. The metal wire S extends reciprocally between surfaces of the adjacent cells in the same row and contacts with the surfaces of the cells to constitute theconductive wires32 in the same row. Then the metal wire S extends reciprocally between a surface of acell31 in a row and a surface of acell31 in another row to constitute multipleconductive wires32 in the same column.

Then, theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 are superposed in sequence, in which the frontadhesive layer20 contacts with theconductive wires32 directly. Finally, theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 are laminated, in which the frontadhesive layer20 fills between adjacentconductive wires32, so as obtain thesolar cell module100 said above.

Specifically, as shown inFIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown inFIG. 8, afirst cell31A and asecond cell31B are prepared. As shown inFIG. 9, a front surface of thefirst cell31A is connected with a metal wire, and a back surface of thesecond cell31B is connected with the metal wire, so as to form acell array30.FIG. 9 shows twocells31. As above, when thecell array30 has a plurality ofcells31, the metal wire extends reciprocally to connect the front surface of thefirst cell31 and the back surface of thesecond cell31 adjacent to thefirst cell31, i.e. connecting secondary grid lines of thefirst cell31 with back electrodes of thesecond cell31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof. The metal wire can be winded only with the help of two clips, which saves the clips considerably and then reduces the assembling space.

In the embodiment shown inFIG. 9, the adjacent cells are connected in series. As above, the adjacent cells can be connected in parallel by the metal wire in the light of practical requirements.

Thecell array30 obtained is superposed with theupper cover plate10, the frontadhesive layer20, the backadhesive layer40 and theback plate50 in sequence, in which the front surfaces of thecells31 face the frontadhesive layer20, and the back surfaces thereof face the backadhesive layer40, and then they are laminated to obtain thesolar cell module100. It can be understood that the metal wire can be bound or welded with thecells31, and the connection of the metal wire and thecells31 can be conducted in the laminating process. Of course, they can be first connected and then laminated.

A method for manufacturing thesolar cell module100 according to another embodiment of the present disclosure will be illustrated with respect toFIG. 1 toFIG. 3 andFIG. 7 toFIG. 9.

Specifically, the method according to the embodiments of the present disclosure includes the following steps:

forming a plurality of conductive wires32 by a metal wire which extends reciprocally a surface of a first cell31 of a plurality of cells31 and a surface of a second cell31 thereof, such that the adjacent cells31 are connected by the plurality of conductive wires32 to constitute a cell array30, wherein the plurality of cells31 are arranged in an n×m matrix form; in a row of cells31, a metal wire extends reciprocally between a surface of a first cell31 and a surface of a second cell31 adjacent to the first cell31; in two adjacent rows of cells31, the metal wire extends reciprocally between a surface of a cell31 in a a^throw and a surface of a cell31 in a (a+1)^throw to obtain the cell array30, n representing a column, m representing a row and m−1≧a≧1, a secondary grid line312 and a short grid line33 being disposed on a front surface of the cell31, the secondary grid line312 including a middle secondary grid line3122 intersected with the conductive wire32 and an edge secondary grid line3121 non-intersected with the conductive wire32, the short grid line33 being connected with the edge secondary grid line3121, and being connected with the conductive wire32 or at least one middle secondary grid line3122, the metal wire being coated with a welding layer by which the metal wire is welded with the middle secondary grid line3122;

superposing theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 in sequence, in which the front surface of thecell31 faces the frontadhesive layer20, and the back surface thereof faces the backadhesive layer40, and laminating them to obtain thesolar cell module100.

Specifically, theshort grid lines33 can be manufactured in the same way as thesecondary grid lines312 on the shiny surface of thecell31, for example, screen printed in conjunction with the secondary grid lines and with the help of the same screen printing plate as the frontsecondary gird lines3121, and theshort grid lines33 may be made of silver paste.

The method includes the steps of preparing asolar array30, superposing theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 in sequence, and laminating them to obtain thesolar cell module100. It can be understood that the method further includes other steps, for example, sealing the gap between theupper cover plate10 and theback plate50 by a sealant, and fixing the above components together by a U-shape frame, which are known to those skilled in the art, and thus will be not described in detail herein.

The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally on surfaces ofcells31 and is electrically connected with the surfaces ofcells31, such that theadjacent cells31 are connected by the plurality of conductive wires to constitute acell array30.

Specifically, as shown inFIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown inFIG. 8, afirst cell31 and asecond cell31 are prepared. As shown inFIG. 9, a front surface of thefirst cell31 is connected with a metal wire, and a back surface of thesecond cell31 is connected with the metal wire, such that thecell array30 is formed.FIG. 9 shows twocells31. When thecell array30 has a plurality ofcells31, the metal wire which extends reciprocally connects the front surface of thefirst cell31 and the back surface of thesecond cell31 adjacent to thefirst cell31, i.e. connecting a secondary grid line of thefirst cell31 with a back electrode of thesecond cell31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof. The metal wire can be winded only with the help of two clips, which saves the clips considerably and then reduces the assembling space.

In the embodiment shown inFIG. 9, the adjacent cells are connected in series. As said above, the adjacent cells can be connected in parallel by the metal wire based on practical requirements.

Thecell array30 obtained is superposed with theupper cover plate10, the frontadhesive layer20, the backadhesive layer40 and theback plate50 in sequence, in which a front surface of thecell31 faces the frontadhesive layer20, a back surface thereof facing the backadhesive layer40, and laminating them to obtain thesolar cell module100. It can be understood that the metal wire can be bounded or welded with thecell31 when or before they are laminated.

The frontadhesive layer20 is disposed in direct contact with theconductive wires32. In the process of laminating, the frontadhesive layer20 melts and fills the gaps between adjacentconductive wires32. The backadhesive layer40 is disposed in direct contact with theconductive wires32. In the process of laminating, the backadhesive layer40 melts and fills the gaps between adjacentconductive wires32.

A method for manufacturing thesolar cell module100 according to the embodiments of the present application will be illustrated with respect toFIG. 7 toFIG. 9, andFIG. 15 toFIG. 18.

The method according to the embodiments of the present invention includes the following steps: forming at least two conductive wires by a metal wire which extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell, welding the metal wire with secondary grid lines on the front surface of the cell, such that adjacent cells are connected by the plurality of conductive wires; breaking the metal wire at turns thereof to obtain acell array30; superposing theupper cover plate10, the frontadhesive layer20, thecell array30, the backadhesive layer40 and theback plate50 in sequence, in which the front surface of thecell31 faces the frontadhesive layer20, and the back surface thereof faces the backadhesive layer40, and laminating them to obtain thesolar cell module100.

The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally surfaces ofcells31 and is electrically connected with the surfaces ofcells31, such that theadjacent cells31 are connected by the plurality of conductive wires to constitute acell array30.

The metal wire is welded with thecell31 under a strain, and after welding, the metal wire is cut off at the turns. In such a way, adjacent cells are connected into acell array30.

Thecell array30 obtained is superposed with theupper cover plate10, the frontadhesive layer20, the backadhesive layer40 and theback plate50 in sequence, in which a front surface of thecell31 faces the frontadhesive layer20, a back surface thereof facing the backadhesive layer40, and laminating them to obtain thesolar cell module100. It can be understood that the metal wire can be connected with thecell31 when or before they are laminated.

In the following, thesolar cell module100 of the present disclosure will be described with respect to specific examples.

Example 1

Example 1 is used to illustrate thesolar cell module100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the metal wire S is obtained.

(2) Manufacturing aSolar Cell Module100

A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1650×1000×3 mm and apolycrystalline silicon cell31 in 156×156×0.21 mm are provided correspondingly. Thecell31 has 91 secondary grid lines (silver, 60 μm width, 9 μm in thickness), each of which substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. Thecell31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the back surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A1 is obtained.

Comparison Example 1

The difference between Comparison example 1 and Example 1 lies in that thecells31 are arranged in a matrix form, and in two adjacent cells, the fifteen parallel metal wires, by wiredrawing as shown inFIG. 13, are strained via theclips34 at the ends of each metal wire, and thus the cells are flattened at a strain of 2 N of the clips. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of afirst cell31 respectively, and welded with back electrodes on a back surface of asecond cell31. The distance between the parallel adjacent conductive wires is 9.9 mm (as shown inFIG. 13). In such a way, a solar cell module D1 is obtained.

Comparison Example 2

The differences between Comparison example 2 and Comparison example 1 lie in that the cells are arranged in a matrix form; 15 metal wires connected in series are pasted at a transparent adhesive layer, and the metal wires are attached to the solar cells. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, and a first transparent adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a second transparent adhesive layer, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. Thus, a solar cell module D2 is obtained.

Example 2

Example 2 is used to illustrate thesolar cell module100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.03 mm², and the alloy layer has a thickness of 10 μm. Hence, the metal wire S is obtained.

(2) Manufacturing a Solar Cell Module

A EVA adhesive layer in 1630×980×0.5 mm is provided (melting point: 60° C.), and a glass plate in 1650×1000×3 mm and apolycrystalline silicon cell31 in 156×156×0.21 mm are provided correspondingly. Thecell31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) at its shiny surface, each of which substantially runs through thecell31 in a longitudinal direction, and the distance between the two adjacent secondary grid lines is 1.7 mm. Thecell31 has five back electrodes (tin, 1.5 mm in width, 10 μm) in thickness) on its back surface. Each back electrode substantially runs through thecell31 in the longitudinal direction, and the distance between the two adjacent back electrodes is 31 mm.

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, so as to form 20 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 7 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the back surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A2 is obtained.

Example 3

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that short grid lines33 (silver, 0.1 mm in width) are disposed on the secondary grid lines of the front surface of thecell31, and are perpendicular to the secondary grid lines for connecting part of the secondary grid lines at the edges of the front surface of the cell with the conductive wires. As shown inFIG. 12, a solar cell module A3 is obtained.

Example 4

The solar cell module is manufactured according to the method in Example 3, but the difference compared with Example 3 lies in that the cell array is connected in such a manner that in two adjacent rows of cells, the conductive wires extend from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of acell31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows ofcells31 are arranged in perpendicular to the conductive wires for connecting theadjacent cells31 in the two rows. In such a way, a solar cell module A4 is obtained.

Testing Example 1

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;

(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 1.

	TABLE 1

	Solar cell module

	A1	D1	D2	A2	A3	A4

Metal wire	no	Slightly	no	no	no	no
drifting
phenomenon
Photoelectric	16.5%	15.6%	15.7%	16.7%	17.0%	17.2%
conversion
efficiency
Series	458	493	482	445	433	429
resistance
(mΩ)
Fill factor	0.779	0.759	0.756	0.783	0.790	0.794
Open-circuit	37.65	37.54	37.63	37.75	37.86	37.88
voltage (V)
Short-circuit	9.048	8.802	8.879	9.085	9.143	9.198
current (A)
Working	31.15	30.38	30.44	31.34	31.76	31.97
voltage (V)
Working	8.520	8.26	8.296	8.571	8.610	8.651
current (A)
Power (W)	265.4	250.9	252.5	268.6	273.4	276.6

The fill factor refers to a ratio of the power at the maximum power point of the solar cell module and the maximum power theoretically at zero resistance, and represents the proximity of the actual power with respect to the theoretic maximum power, in which the greater the value is, the higher the photoelectric conversion efficiency is. Generally, the series resistance is small, so the fill factor is great. The photoelectric conversion efficiency refers to a ratio of converting the optical energy into electric energy by the module under a standard lighting condition (1000 W/m²of light intensity). The series resistance is equivalent to the internal resistance of the solar module, in which the greater the value is, the poorer the performance of the module is. The fill factor represents a ratio of the actual maximum power and the theoretical maximum power of the module, in which the greater the value is, the better the performance of the module is. The open-circuit voltage refers to the voltage of the module in an open circuit under a standard lighting condition. The short-circuit current refers to the current of the module in a short circuit under a standard lighting condition. The working voltage is the output voltage of the module working with the largest power under a standard lighting condition. The working current is the output current of the module working with the largest power under a standard lighting condition. The power is the maximum power which the module can reach under a standard lighting condition.

It can be indicated from Table 1 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Testing Example 2

(1) Welding a metal wire onto a surface of a cell, the metal wire being in perpendicular to secondary grid lines of the cell;

(2) Placing the cell horizontally at a testing position of a tensile tester, and pressing blocks on the cell, in which the pressing blocks are disposed at two sides of the metal wire, such that the cell will not be pulled up during the test;

(3) Clamping the metal wire at a pull ring of a tension meter that forms an angle of 45° with the cell;

(4) Actuating the tension meter, such that the tension meter moves uniformly along a vertical direction, pulls up the metal wire from the surface of the cell and records the pull data tested, in which the data is averaged to obtain the pull data of the metal wire. The testing result is shown in Table 2.

TABLE 2

Module	A1	D1	D2	A2	A3	A4

Tensile force (N)	0.45	0.38	0.25	0.26	0.34	0.33

It can be indicated from Table 2 that for the solar cell module according to the embodiments of the present disclosure, greater tensile force is needed to pull the metal wire away from the upper gall of the cell, which proves stronger stability of connection between the metal wire and the cell in the solar cell module.

Example 21

Example 21 is used to illustrate thesolar cell module100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

(2) Manufacturing aSolar Cell Module100

A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1650×1000×3 mm and apolycrystalline silicon cell31 in 156×156×0.21 mm are provided correspondingly. Thecell31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) on its front surface, each of which substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm.

The short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 5.1 mm and a width of 0.2 mm. There are eight short grid lines.

Thecell31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, and is intersected with the short gird lines at the turns formed by reciprocal extension, so as to form 15 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and identical metal wires are arranged in the above way to obtain the same conductive wires, such that six rows of the cells of such kind are connected in series into a cell array. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the back surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A21 is obtained.

Comparison Example 21

The difference of Comparison example 21 and Example 21 lies in that a conventional grid mesh is employed, and the short grid lines are not printed at the same time of printing the secondary grid lines. In such a way, a solar cell module D21 as shown inFIG. 12 is obtained.

Comparison Example 22

The differences between Comparison example 22 and Comparison example 21 lie in that the cells are arranged in a matrix form; 15 metal wires connected in series are pasted at a transparent adhesive layer, and the metal wires are attached to the solar cells. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, and a first transparent adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a second transparent adhesive layer, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. Thus, a solar cell module D22 is obtained.

Comparison Example 23

The difference of Comparison example 23 and Example 21 lies in that thecells31 are arranged in a matrix form, and in twoadjacent cells31, each of the fifteen parallel metal wires, by wiredrawing as shown inFIG. 13, is strained by theclips34 at the ends thereof to flatten the cell. the strain from the clips is 2N, such that each of the fifteen parallel metal wires is welded with a secondary grid line on a front surface of afirst cell31 respectively, and welded with a back electrode on a back surface of asecond cell31. The distance between of the adjacentconductive wires32C in parallel to each other is 9.9 mm. In such a way, a solar cell module D23 is obtained.

Example 22

Example 22 is used to illustrate thesolar cell module100 according to the present disclosure and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

(2) Manufacturing a Solar Cell Module

A EVA adhesive layer in 1630×980×0.5 mm is provided (melting point: 60° C.), and a glass plate in 1650×1000×3 mm and apolycrystalline silicon cell31 in 156×156×0.21 mm are provided correspondingly. Thecell31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) at its shiny surface, each of which substantially runs through thecell31 in a longitudinal direction, and the distance between the two adjacent secondary grid lines is 1.7 mm. Thecell31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through thecell31 in the longitudinal direction, and the distance between the two adjacent back electrodes is 31 mm.

The short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 3.4 mm and a width of 0.1 mm. There are ten short grid lines.

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under strain. The metal wire extends reciprocally under strain from two clips at two ends thereof, and is intersected with the short gird lines at the turns formed by reciprocal extension, so as to form 20 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 7 mm. 10 cells are connected in series into a row, and identical metal wires are arranged in the above way to obtain the same conductive wires, such that six rows of the cells of such kind are connected in series into a cell array. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the back surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A22 is obtained.

Example 23

The solar cell module is manufactured according to the method in Example 22, but the difference compared with Example 22 lies in that the short grid lines are printed at an edge of a side of the front surface of the cell by a newly designed secondary grid mesh at the same time of printing the secondary grid lines. The short grid lines are perpendicular to the secondary grid lines, and connected with the outermost secondary grid line at the edge. The short grid line printed has a length of 5.1 mm and a width of 0.15 mm. There are ten short grid lines. The turn formed by reciprocal extension is located between the second and the third short grid lines. The short grid lines are intersected with the third secondary grid line.

Example 24

The solar cell module is manufactured according to the method in Example 22, but the difference compared with Example 22 lies in that after being welded the secondary grid lines, the metal wire cuts the arc segments at the turns to form separate and parallel 20 metal wires. The distance between adjacent parallel primary grid lines is 7 mm. In such a way, a solar cell module A24 is obtained.

Example 25

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that the alloy layer is 50% Sn-48% Bi-1.5% Ag-0.5% Cu (melting point: 160° C.). In such a way, a solar cell module A25 is obtained.

Example 26

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that the alloy layer is 58% Bi-42% Sn. In such a way, a solar cell module A26 is obtained.

Example 27

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that the alloy layer is 65% Sn-20% Bi-10% Pb-5% Zn. In such a way, a solar cell module A27 is obtained.

Testing Example 21

(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 3.

	TABLE 3

	Solar cell module

	A21	D21	D22	D23	A22	A23	A24	A25	A26	A27

Metal wire	no	Slightly	no	Slightly	no	no	no	no	no	no
drifting
phenomenon
Photoelectric	17.30%	15.50%	15.30%	15.6%	17.10%	17.05%	17.20%	16.70%	17.00%	16.80%
conversion
efficiency
Series	425	498	515	493	442	445	427	445	433	448
resistance
(mΩ)
Fill factor	0.796	0.764	0.742	0.759	0.788	0.79	0.793	0.783	0.79	0.781
Open-circuit	37.94	37.44	37.52	37.54	37.85	37.71	37.9	37.75	37.86	37.81
voltage (V)
Short-circuit	9.212	8.712	8.836	8.802	9.22	9.206	9.198	9.085	9.143	9.154
current (A)
Working	31.92	30.49	30.32	30.38	31.86	31.84	31.97	31.34	31.76	31.69
voltage (V)
Working	8.717	8.176	8.117	8.26	8.633	8.611	8.651	8.571	8.61	8.53
current (A)
Power (W)	278.2	249.3	246.1	250.9	275	274.2	276.6	268.6	273.4	270.3

Testing Example 22

(4) Actuating the tension meter, such that the tension meter moves uniformly along a vertical direction, pulls up the metal wire from the surface of the cell and records the pull data tested, in which the data is averaged to obtain the pull data of the metal wire. The testing result is shown in Table 4.

TABLE 4

Module	A21	D21	D22	D23	A22	A23	A24	A25	A26	A27

Tensile force (N)	0.45	0.38	0.25	0.26	0.34	0.33	0.39	0.48	0.43	0.37

It can be indicated from Table 4 that for the solar cell module according to the embodiments of the present disclosure, greater tensile force is needed to pull the metal wire away from the upper gall of the cell, which proves stronger stability of connection between the metal wire and the cell in the solar cell module.

Example 31

Example 31 is used to illustrate thesolar cell module100 according to the present application and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

(2) Manufacturing aSolar Cell Module100

A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1650×1000×3 mm and apolycrystalline silicon cell31 in 156×156×0.21 mm are provided correspondingly. Thecell31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. Thecell31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through thecell31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. The metal wire is cut off at the turns. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the shady surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A31 is obtained.

Comparison Example 31

The difference between Comparison example 31 and Example 31 lies in that thecells31 are arranged in a matrix form, and in two adjacent cells, the fifteen parallel metal wires, by wiredrawing as shown inFIG. 17, are strained via theclips34 at the ends of each metal wire, and thus the cells are flattened at a strain of 2N of the clips. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of afirst cell31 respectively, and welded with back electrodes on a back surface of asecond cell31. The distance between the parallel adjacentconductive wires32C is 9.9 mm (as shown inFIG. 13). In such a way, a solar cell module D31 is obtained.

Comparison Example 32

The differences between Comparison example 32 and Comparison example 31 lie in that the cells are arranged in a matrix form; 15 metal wires connected in series are pasted at a transparent adhesive layer, and the metal wires are attached to the solar cells. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, and a first transparent adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a second transparent adhesive layer, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. Thus, a solar cell module D32 is obtained.

Example 32

Example 32 is used to illustrate thesolar cell module100 according to the present application and the manufacturing method thereof.

(1) Manufacturing a Metal Wire S

(2) Manufacturing a Solar Cell Module

60cells31 are arranged in a matrix form (six rows and ten columns). In twoadjacent cells31 in a row, a metal wire extends reciprocally between a front surface of afirst cell31 and a back surface of asecond cell31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 20 parallel conductive wires. The secondary grid lines of thefirst cell31 are welded with the conductive wires and the back electrodes of thesecond cell31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 7 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. The metal wire is cut off at the turns. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of thecell31 faces the frontadhesive layer20, such that the frontadhesive layer20 contacts with theconductive wires32 directly; and the shady surface of thecell31 faces the backadhesive layer40, and finally they are laminated in a laminator, in which the frontadhesive layer20 fills between adjacentconductive wires32. In such way, a solar cell module A32 is obtained.

Example 33

The solar cell module is manufactured according to the method in Example 32, but the difference compared with Example 32 lies in that short grid lines33 (silver, 0.1 mm in width) are disposed on thesecondary grid lines312 of the shiny surface of thecell31, and are perpendicular to thesecondary grid lines312 for connecting part of thesecondary grid lines312 at the edges of the shiny surface of thecell31 with theconductive wires32. As shown inFIG. 12, a solar cell module A33 is obtained.

Example 34

The solar cell module is manufactured according to the method in Example 33, but the difference compared with Example 33 lies in that the cell array is connected in such a manner that in two adjacent rows of cells, the conductive wires extend from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of acell31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows ofcells31 are arranged in perpendicular to the conductive wires for connecting theadjacent cells31 in the two rows. In such a way, a solar cell module A34 is obtained.

Testing Example 31

(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 5.

	TABLE 5

	Solar cell module

	A31	D31	D32	A32	A33	A34

Metal wire	no	Slightly	no	no	no	no
drifting
phenomenon
Photoelectric	16.5%	15.6%	15.7	16.7%	17.0%	17.2%
conversion
efficiency
Series	458	493	482	445	433	429
resistance
(mΩ)
Fill factor	0.779	0.759	0.756	0.783	0.790	0.794
Open-circuit	37.65	37.54	37.63	37.75	37.86	37.88
voltage (V)
Short-circuit	9.048	8.802	8.879	9.085	9.143	9.198
current (A)
Working	31.15	30.38	30.44	31.34	31.76	31.97
voltage (V)
Working	8.520	8.26	8.296	8.571	8.610	8.651
current (A)
Power (W)	265.4	250.9	252.5	268.6	273.4	276.6

It can be indicated from Table 5 that for the solar cell module according to the embodiments of the present application, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Testing Example 32

(4) Actuating the tension meter, such that the tension meter moves uniformly along a vertical direction, pulls up the metal wire from the surface of the cell and records the pull data tested, in which the data is averaged to obtain the pull data of the metal wire. The testing result is shown in Table 6.

TABLE 6

Module	A31	D31	D32	A32	A33	A34

Tensile force (N)	0.45	0.38	0.25	0.26	0.34	0.33

It can be indicated from Table 6 that for the solar cell module according to the embodiments of the present application, greater tensile force is needed to pull the metal wire away from the upper gall of the cell, which proves stronger stability of connection between the metal wire and the cell in the solar cell module.

In the specification, it is to be understood that terms such as “central,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation.

In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with “first” and “second” may comprise one or more of this feature. In the description of the present disclosure, “a plurality of” means two or more than two, unless specified otherwise.

In the present disclosure, unless specified or limited otherwise, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature “below,” “under,” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below,” “under,” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature.

Reference throughout this specification to “an embodiment,” “some embodiments,” or “some examples” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, these terms throughout this specification do not necessarily refer to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Although embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations can be made in the embodiments without departing from the scope of the present disclosure.