CROSS REFERENCE TO RELATED APPLICATIONSThis application is a continuation of U.S. patent application Ser. No. 14/067,688, filed on Oct. 30, 2013, which is a continuation of U.S. patent application Ser. No. 12/784,392, filed on May 20, 2010, now U.S. Pat. No. 8,584,406, issued on Nov. 19, 2013, which claims the benefit of U.S. Provisional Application No. 61/179,991, filed May 20, 2009, the entire contents of which are hereby incorporated by reference herein.
This invention was made with Government support under Contract No. DEFC36-07G017043 awarded by the United States Department of Energy. The Government has certain rights in this invention.
TECHNICAL FIELDEmbodiments of the present invention are in the field of photovoltaic systems and, in particular, hole-thru-laminate mounting supports for photovoltaic modules.
BACKGROUNDPhotovoltaic cells, commonly known as solar cells, are well known devices for direct conversion of solar radiation into electrical energy. Generally, solar cells are fabricated on a semiconductor wafer or substrate using semiconductor processing techniques to form a p-n junction near a surface of the substrate. Solar radiation impinging on the surface of the substrate creates electron and hole pairs in the bulk of the substrate, which migrate to p-doped and n-doped regions in the substrate, thereby generating a voltage differential between the doped regions. The doped regions are coupled to metal contacts on the solar cell to direct an electrical current from the cell to an external circuit coupled thereto. Generally, an array of solar cells, each solar cell interconnected, is mounted on a common or shared platform to provide a photovoltaic module. A plurality of photovoltaic modules or module groups may be electrically coupled to an electrical power distribution network, forming a photovoltaic system.
A photovoltaic module may be composed of a photovoltaic laminate. Mounting such a photovoltaic module, e.g. on a roof-top, may be difficult because the photovoltaic laminate may be relatively large and readily breakable. A photovoltaic laminate may be mounted by securing the laminate by its edge with glue or by physical clamping. Such approaches may prove expensive and bulky as mounting techniques and apparatuses for mounting photovoltaic modules composed of photovoltaic laminates. Accordingly, additional improvements are needed in the evolution of photovoltaic laminate mounting technology.
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1A illustrates a top-down view of a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.
FIG. 1B illustrates a cross-sectional view of the mounting support ofFIG. 1A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
FIG. 1C illustrates a cross-sectional view of the mounting support ofFIG. 1A, taken along the b-b′ axis, in accordance with an embodiment of the present invention.
FIG. 2A illustrates a top-down view of a mounting support for a photovoltaic module, the mounting support including a spacer, in accordance with an embodiment of the present invention.
FIG. 2B illustrates a cross-sectional view of the mounting support ofFIG. 2A, taken along the a-a′ axis, the mounting support including a spacer, in accordance with an embodiment of the present invention.
FIG. 2C illustrates a cross-sectional view of the mounting support ofFIG. 2A, taken along the b-b′ axis, the mounting support including a spacer, in accordance with an embodiment of the present invention.
FIG. 3 illustrates a cross-sectional view of a mounting support for a photovoltaic module, the mounting support including a pedestal consisting essentially of a unitary body, in accordance with an embodiment of the present invention.
FIG. 4A illustrates a top-down view of a photovoltaic system including a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.
FIG. 4B illustrates a cross-sectional view of the photovoltaic system ofFIG. 4A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
FIG. 5A illustrates a bottom-up view of a photovoltaic system including a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.
FIG. 5B illustrates a cross-sectional view of the photovoltaic system ofFIG. 5A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
FIG. 6 depicts a Flowchart representing a series of operations in a method for fabricating a photovoltaic system, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTIONA hole-thru-laminate mounting support for a photovoltaic module is described herein. In the following description, numerous specific details are set forth, such as specific photovoltaic system arrangements, in order to provide a thorough understanding of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known fabrication operations, such as solar cell lamination operations, are not described in detail in order to not unnecessarily obscure embodiments of the present invention. Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale.
Disclosed herein is a mounting support for a photovoltaic module. The mounting support may include a pedestal having a surface adaptable to receive a flat side of a photovoltaic module laminate. In one embodiment, a hole is disposed in the pedestal, the hole adaptable to receive a bolt or a pin used to couple the pedestal to the flat side of the photovoltaic module laminate. Also disclosed herein is a photovoltaic system. The photovoltaic system may include a plurality of photovoltaic module laminates. In one embodiment, the photovoltaic system also includes a plurality of pedestals. Each pedestal includes a surface coupled to a flat side of one or more of the photovoltaic module laminates and one or more holes disposed in the pedestal. A plurality of bolts or pins couples each pedestal of the plurality of pedestals to one or more of the plurality of photovoltaic module laminates, each bolt or pin disposed through one of the plurality of photovoltaic module laminates and inside of one of the one or more holes. Also disclosed herein is a method for fabricating a photovoltaic system. The method may include providing a plurality of photovoltaic module laminates. In one embodiment, a plurality of pedestals is also provided. Each pedestal includes a surface for coupling to a flat side of one or more of the plurality of photovoltaic module laminates and one or more holes disposed in the pedestal. Each pedestal of the plurality of pedestals is coupled to one or more of the plurality of photovoltaic module laminates with a plurality of bolts or pins, the coupling comprising inserting each bolt or pin through one of the plurality of photovoltaic module laminates and inside of one of the one or more holes.
A mounting support for a photovoltaic module laminate, the mounting support including a pedestal, may be useful for optimizing or maximizing the amount of radiation collectable by a bifacial solar module. For example, in accordance with an embodiment of the present invention, the use of a mounting support including a pedestal essentially eliminates the need to secure the photovoltaic module laminate by its edge, conventional edge-securing otherwise blocking back-side radiation collection around the edge of the module. Furthermore, such a mounting support may be smaller and less expensive than conventional mounting structures. In accordance with another embodiment of the present invention, a mounting support for a photovoltaic module laminate, the mounting support including a pedestal, does not significantly impede or interfere with cooling, e.g. by wind or air gradients, of the photovoltaic module laminate. Such impedance or interference of cooling by conventional mounting supports may lead to reduced efficiency of energy conversion by a mounted solar module.
In accordance with an embodiment of the present invention, a hole-thru-laminate approach is enabled by using a pedestal as a mounting support for a photovoltaic module laminate. For example, in one embodiment, a bolt or pin is used to couple the mounting support directly to the photovoltaic module laminate via aligned holes formed directly in the pedestal of the mounting support and the photovoltaic module laminate. In a specific embodiment, the direct hole-through-laminate mounting approach is enabled by bifacial arrangement (e.g. a lower solar cell density and, therefore, space for holes between the cells) of the photovoltaic module laminate. In a particular example of that embodiment, the mounting support only minimally shades the back-side of a bifacial solar cell module arrangement because already available space between the cells is used for holes. However, in another specific embodiment, the direct hole-through-laminate mounting approach is not hindered by a higher density arrangement, such as a mono-facial solar cell module arrangement. In accordance with an embodiment of the present invention, a mounting support for a photovoltaic module laminate, the mounting support including a pedestal, is used for mounting a plurality of photovoltaic module laminates on a roof-top having less than approximately 5 degree tilt. In an embodiment, a conventional thickness of glass used in a photovoltaic laminate module otherwise required for use with a conventional mounting system can be reduced because the mounting support, including the pedestal, is better able to accommodate photovoltaic laminate modules with increased fragility.
In an aspect of the present invention, a mounting support for a photovoltaic module is provided.FIG. 1A illustrates a top-down view of a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.
Referring toFIG. 1A, a mounting support for a photovoltaic module includes apedestal100 having asurface102 adaptable to receive a flat side of a photovoltaic module laminate. Ahole104 is disposed inpedestal100,hole104 adaptable to receive a bolt or a pin used to couplepedestal100 to the flat side of a photovoltaic module laminate.
In an embodiment,pedestal100 includes a bottom portion detachable from a top portion. For example,FIG. 1B illustrates a cross-sectional view of the mounting support ofFIG. 1A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
Referring toFIG. 1B,pedestal100 includes abottom portion106 detachable from atop portion108. In one embodiment,top portion108 includeshole104, as depicted inFIG. 1B. In an embodiment,bottom portion106 includes asecond hole110, as is also depicted inFIG. 1B. In a specific embodiment,second hole110 is adaptable to receive a bolt or a pin used to couplebottom portion106 ofpedestal100 to a roof or ground support system. In another specific embodiment,second hole110 is adaptable to receive a bolt or a pin used to couplebottom portion106 ofpedestal100 to a reflective layer.
Referring to bothFIGS. 1A and 1B, in accordance with an embodiment of the present invention, bothbottom portion106 andtop portion108 ofpedestal100 minor the same dog-bone shape. In one embodiment,top portion108 includes three or moreadditional holes104′,104″ and104′″ disposed therein, the three or moreadditional holes104′,104″ and104′″ adaptable to receive a bolt or a pin used to couplepedestal100 to a flat side of one or more additional photovoltaic module laminates. In one embodiment,bottom portion106 also includes three or more additional holes disposed therein (additional hole110′ is shown inFIG. 1B), the three or more additional holes adaptable to receive a bolt or a pin used to couplepedestal100 to a roof or ground support system or to one or more reflective layers. By using a top and bottom portion ofpedestal100 that mirror the same shape, convenience of fabrication may be realized. For example, in an embodiment, the same fabrication mold is used for producing bothbottom portion106 andtop portion108 ofpedestal100. In one embodiment, bothbottom portion106 andtop portion108 ofpedestal100 are fabricated from the same fabrication mold and are composed of a material such as, but not limited to Noryl® plastic. In an embodiment, not depicted, instead of mirroring the same dog-bone shape, bothbottom portion106 andtop portion108 ofpedestal100 minor the same cross shape.
Bottom portion106 andtop portion108 ofpedestal100 may be coupled together by a process that provides a seemingly unified pedestal for supporting a photovoltaic module. For example,FIG. 1C illustrates a cross-sectional view of the mounting support ofFIG. 1A, taken along the b-b′ axis, in accordance with an embodiment of the present invention.
Referring toFIGS. 1A and 1C, bothbottom portion106 andtop portion108 ofpedestal100 include atrench114 having a hole adaptable to receive a bolt or apin112 used to couplebottom portion106 andtop portion108. In an embodiment, upon couplingbottom portion106 andtop portion108, a seeminglyunified pedestal100 is provided for supporting a photovoltaic module,pedestal100 having asurface102 adaptable to receive a flat side of a photovoltaic module laminate.
In an aspect of the present invention,pedestal100 may further include a spacer to aid in the isolation of a plurality of photovoltaic module laminates from each other and to aid in the alignment of the modules with respect to each other (e.g. long straight rows). For example,FIG. 2A illustrates a top-down view of a mounting support for a photovoltaic module, the mounting support including a spacer, in accordance with an embodiment of the present invention.FIG. 2B illustrates a cross-sectional view of the mounting support ofFIG. 2A, taken along the a-a′ axis, the mounting support including a spacer, in accordance with an embodiment of the present invention.FIG. 2C illustrates a cross-sectional view of the mounting support ofFIG. 2A, taken along the b-b′ axis, the mounting support including a spacer, in accordance with an embodiment of the present invention.
Referring toFIGS. 2A-2C, apedestal200 includes aspacer220 adaptable to be disposed on, but detachable from,top portion108 ofpedestal200. In one embodiment, the top surface ofspacer220 is abovesurface102 ofpedestal100,surface102 adaptable to receive a flat side of a photovoltaic module laminate. In accordance with an embodiment of the present invention,spacer220 has a cross-shape, as depicted inFIGS. 2A-2C. In an embodiment, spacer220 couples totop portion108 ofpedestal200 by a mechanical fastener, either molded intoparts108 and220, or separate. Alternatively, an adhesive may be used.
In another aspect of the present invention, a pedestal may be composed of a unitary body, as opposed to two mirrored portions. For example,FIG. 3 illustrates a cross-sectional view of a mounting support for a photovoltaic module, the mounting support including a pedestal consisting essentially of a unitary body, in accordance with an embodiment of the present invention.
Referring toFIG. 3, apedestal300 is composed of aunitary body308.Pedestal300 includessurfaces302 adaptable to receive a flat side of one or more photovoltaic module laminates.Pedestal300 also includesholes304 disposed inpedestal300,holes304 adaptable to receive a bolt or a pin used to couplepedestal300 to the flat side of the one or more photovoltaic module laminates. In accordance with an embodiment of the present invention,unitary body308 ofpedestal300 is fabricated from a single mold process.
In the case that a unitary arrangement is used for a pedestal in a mounting support, the unitary arrangement is not limited to that configuration depicted in and described in association withFIG. 3. For example, in an embodiment, a different unitary arrangement is used, depending upon the location of the pedestal in a photovoltaic system including a plurality of pedestals. In one embodiment, a unitary central pedestal, such as but not limited to the pedestal described inFIG. 3, is used at the intersection of four photovoltaic laminate modules. In that embodiment, an edge unitary pedestal is used at the edge of the photovoltaic system where only two photovoltaic module laminates meet, and a corner unitary pedestal is used at the corner of the photovoltaic system where only one photovoltaic module laminate resides. Alternatively, in accordance with yet another embodiment of the present invention, a pedestal in a mounting support is composed of two or more portions separated vertically, as opposed to horizontally like the pedestals described in association withFIGS. 1A-1C and2A-2C.
In an aspect of the present invention, a photovoltaic system includes one or more pedestals, such as those pedestals described above. For example,FIG. 4A illustrates a top-down view of a photovoltaic system including a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.FIG. 4B illustrates a cross-sectional view of the photovoltaic system ofFIG. 4A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
Referring toFIGS. 4A and 4B, aphotovoltaic system400 includes a plurality of photovoltaic module laminates440,441,442 and443.Photovoltaic system400 also includes a plurality of pedestals (one of which,pedestal401, is depicted inFIGS. 4A and 4B). Eachpedestal401 includes asurface402 coupled to aflat side499 of one or more of the plurality of photovoltaic module laminates440,441,442 and443. One or more holes is disposed inpedestal401 and a plurality of bolts or pins404 couples eachpedestal401 of the plurality of pedestals to one or more of the plurality of photovoltaic module laminates440,441,442 and443. Each bolt or pin404 is disposed through one of the plurality of photovoltaic module laminates440,441,442 and443 and inside of one of the one or more holes. Thus, in accordance with an embodiment of the present invention, a hole-thru-laminate approach is used to fabricate a photovoltaic system.
Photovoltaic module laminates440,441,442 and443 may be composed of a variety of layers used for optimizing solar energy conversion. For example, in accordance with an embodiment of the present invention, photovoltaic module laminates440,441,442 and443 each include a layer of EVA material, a layer with an array of solar cells, a sheet of glass, a J-Box and electrical buses. Referring again toFIG. 4A, the individual solar cells of photovoltaic module laminates440,441,442 and443 are represented by the smaller squares within each of illustrated photovoltaic module laminates440,441,442 and443. In one embodiment, eachphotovoltaic module laminate440,441,442 and443 is a bifacial laminate, arranged to accept solar radiation impingent on at least two sides of the laminate, e.g., impinging upon the top-surface and the back-surface of the laminate. In a specific embodiment, eachphotovoltaic module laminate440,441,442 and443 is a bifacial laminate having less than approximately 70% solar cell array density.
The holes formed in eachphotovoltaic module laminate440,441,442 and443 may include a flexible rubber grommet. In an embodiment, inclusion of such a grommet in each hole allows eachphotovoltaic module laminate440,441,442 and443 to move relative to a supporting pedestal and accommodates slight changes in the slope of a roof-top on which a photovoltaic system is mounted. The location of the holes in eachphotovoltaic module laminate440,441,442 and443 may be selected to optimize the positioning of supporting pedestals without shorting adjacent solar cells. In an embodiment, eachphotovoltaic module laminate440,441,442 and443 includes 4 holes, each hole at the corner of the laminate. In another embodiment, eachphotovoltaic module laminate440,441,442 and443 includes 4 holes, each hole offset from the corners and within the array of solar cells. In another embodiment, the size of eachphotovoltaic module laminate440,441,442 and443 is extended without adding additional solar cells, in order to accommodate the holes.
Eachpedestal401 of the plurality of pedestals may include a bottom portion detachable from a top portion. Referring toFIG. 4B, in an embodiment,pedestal401 includes abottom portion406 detachable from atop portion408. In an embodiment,top portion408 includes the one or more holes described above forpedestal401. In an embodiment,bottom portion406 includes an additional one ormore holes410. In a specific embodiment, bothbottom portion406 andtop portion408 ofpedestal401 mirror the same dog-bone shape. In that embodiment,top portion408 includes four or more holes disposed therein, the four or more holes adaptable to receive bolts or pins used to couplepedestal401 to the flat side of photovoltaic module laminates440,441,442 and443, as depicted inFIG. 4A. In an alternative embodiment, eachpedestal401 of the plurality of pedestals consists essentially of a unitary body.
In accordance with an embodiment of the present invention, eachpedestal401 of the plurality of pedestals further includes aspacer420, as depicted in both FIGS.4A and4B. In a specific embodiment,spacer420 is adaptable to be disposed on, but detachable from,top portion408 ofpedestal401. In a particular embodiment, the top surface ofspacer420 is abovesurface402 ofpedestal401,surface402 ofpedestal401 adaptable to receive the flat sides of each of the plurality of photovoltaic module laminates440,441,442 and443. In that embodiment,spacer420 is adjacent to each of the plurality of photovoltaic module laminates440,441,442 and443, as depicted inFIG. 4A.
In an aspect of the present invention, reflective layers may be included in a photovoltaic system. For example,FIG. 5A illustrates a bottom-up view of a photovoltaic system including a mounting support for a photovoltaic module, in accordance with an embodiment of the present invention.FIG. 5B illustrates a cross-sectional view of the photovoltaic system ofFIG. 5A, taken along the a-a′ axis, in accordance with an embodiment of the present invention.
Referring to bothFIGS. 5A and 5B, the additional one ormore holes410 ofbottom portion406 ofpedestal401 is adaptable to receive a bolt or apin510 used to couplebottom portion406 ofpedestal401 to one or morereflective layers550. In one embodiment,bottom portion406 includes four or more holes disposed therein, the four or more holes adaptable to receive bolts or pins510 used to couplepedestal401 to fourreflective sheets550, as depicted inFIG. 5A. However, in an alternative embodiment, the additional one ormore holes410 ofbottom portion406 ofpedestal401 is adaptable to receive a bolt or apin510 used to couplebottom portion406 ofpedestal401 to a roof or ground support system.
In an aspect of the present invention, a photovoltaic system may be fabricated to include a plurality of photovoltaic module laminates and a plurality of pedestals. For example,FIG. 6 depicts aFlowchart600 representing a series of operations in a method for fabricating a photovoltaic system, in accordance with an embodiment of the present invention.
Referring tooperation602 ofFlowchart600, a method for fabricating a photovoltaic system includes providing a plurality of photovoltaic module laminates. In accordance with an embodiment of the present invention, the plurality of photovoltaic module laminates includes photovoltaic module laminates such as those described in association withFIGS. 4A and 4B.
Referring tooperation604 ofFlowchart600, the method includes providing a plurality of pedestals, each pedestal including a surface for coupling to a flat side of one or more of the plurality of photovoltaic module laminates. In accordance with an embodiment of the present invention, each pedestal also includes one or more holes disposed in the pedestal.
In an embodiment, providing each pedestal of the plurality of pedestals includes providing a top portion of each pedestal, the top portion including the one or more holes. In that embodiment, providing each pedestal of the plurality of pedestals also includes providing a bottom portion of each pedestal, the bottom portion detachable from the top portion, and the bottom portion including an additional one or more holes. The top portion is then coupled to the bottom portion.
In a specific embodiment, providing both the bottom portion and the top portion of the pedestal includes providing portions mirroring the same dog-bone shape, the top portion comprising four or more holes disposed therein. The four or more holes are adaptable to receive bolts or pins used to couple the pedestal to the flat side of four photovoltaic module laminates. Also, in that embodiment, the bottom portion includes four or more holes disposed therein, the four or more holes adaptable to receive bolts or pins used to couple the pedestal to a roof or ground support system or to up to four reflective sheets.
In another specific embodiment, providing each pedestal of the plurality of pedestals further includes providing a spacer on, but detachable from, the top portion of the pedestal. The top surface of the spacer is above the surface of the pedestal that is provided for coupling to the flat side of the one or more of the plurality of photovoltaic module laminates. Additionally, the spacer is adjacent to one or more of the plurality of photovoltaic module laminates. In an alternative embodiment, providing each pedestal of the plurality of pedestals includes providing a pedestal consisting essentially of a unitary body.
In accordance with an embodiment of the present invention, the method further includes coupling the bottom portion of each pedestal to a reflective layer, the coupling including inserting a bolt or a pin through the reflective layer and inside of one of the additional one or more holes of the bottom portion. However, in an alternative embodiment, the method further includes coupling the bottom portion of each pedestal to a roof or ground support system, the coupling including inserting a bolt or a pin in each of the additional one or more holes of the bottom portion.
Referring tooperation606 ofFlowchart600, the method includes coupling each pedestal of the plurality of pedestals to one or more of the plurality of photovoltaic module laminates with a plurality of bolts or pins. In accordance with an embodiment of the present invention, the coupling includes inserting each bolt or pin through one of the plurality of photovoltaic module laminates and inside of one of the one or more holes.
Thus, a mounting support for a photovoltaic module has been disclosed. In accordance with an embodiment of the present invention, the mounting support includes a pedestal having a surface adaptable to receive a flat side of a photovoltaic module laminate. A hole is disposed in the pedestal, the hole adaptable to receive a bolt or a pin used to couple the pedestal to the flat side of the photovoltaic module laminate. In one embodiment, the pedestal includes a bottom portion detachable from a top portion, the top portion comprising the hole, and the bottom portion comprising a second hole. In another embodiment, the pedestal is composed of a unitary body.