CN112730217A - Puncturing device and method for testing puncturing strength of lithium battery diaphragm - Google Patents

Abstract

A puncturing device for testing the puncturing strength of a lithium battery diaphragm comprises a detection support, wherein the detection support comprises an upper base, a guide rod and a lower base; a guide rod is vertically arranged on the surface of the lower base, a base is arranged at the top end of the guide rod, a sliding seat is slidably mounted on the outer wall of the guide rod, an ejector pin is vertically arranged at the center of the bottom surface of the sliding seat, an upper clamp is detachably mounted on the outer wall of the bottom end of the ejector pin, a lower clamp is mounted at the bottom of the upper clamp, a diaphragm with the same outer diameter is arranged at the top end of the lower clamp, the diaphragm is embedded in the upper clamp, and air guide holes distributed in an annular array are formed in the lower clamp; the diaphragm is more uniformly stressed when placed on the lower fixture, the attaching effect of the diaphragm and the fixture is better, and the accuracy and the repeatability of the test are improved.

Description

Puncturing device and method for testing puncturing strength of lithium battery diaphragm

Technical Field

The invention belongs to the technical field of lithium battery processing, and particularly relates to a puncturing device and method for testing the puncturing strength of a lithium battery diaphragm.

Background

The battery diaphragm is one of important raw materials of the lithium ion battery, and plays an important role in ensuring the performance and the safety of the lithium ion battery; the performance of the membrane determines the interface structure and internal resistance of the battery, so that the key characteristics of the battery, such as capacity, cycle performance, charge-discharge current density and the like, are influenced, meanwhile, in the manufacturing process, due to the conditions that the surface coating of an electrode is not smooth enough, burrs are arranged on the edge of the electrode and the like, and the process level is limited in the assembly process, the membrane needs to bear large pressure, and in order to prevent short circuit, the membrane needs to have considerable puncture strength.

When the existing test fixture is used for testing, the diaphragm is fixed by the lock catch between the upper fixture and the lower fixture, the diaphragm can move when the lock catch is screwed, the stress is not uniform due to poor fitting effect of the diaphragm and the fixtures, the difference of operation and detection results of different personnel is large, the data fluctuation is large, and the accuracy and the repeatability of the test are seriously disturbed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a puncturing device for testing the puncturing strength of a lithium battery diaphragm, and the specific technical scheme is as follows:

a puncturing device for testing the puncturing strength of a lithium battery diaphragm comprises a detection support, wherein the detection support comprises an upper base, a guide rod and a lower base; the surface of lower base is equipped with the guide arm perpendicularly, the top upper base of guide arm, the outer wall slidable mounting of guide arm has the slide, the bottom surface center department of slide is equipped with the thimble perpendicularly, the bottom outer wall demountable installation of thimble has last anchor clamps, the bottom of going up anchor clamps is installed down anchor clamps, the top of anchor clamps is equipped with the diaphragm that the external diameter is the same down, the diaphragm imbeds in last anchor clamps, the inside of anchor clamps is seted up the gas guide hole that the annular array distributes down, the bottom of diaphragm is arranged in to the top opening of gas guide hole, each the bottom opening of gas guide hole all communicates to vacuum mechanism, vacuum mechanism is used for the negative pressure to adsorb the diaphragm.

Furthermore, the upper clamp comprises a ring plate part and a top plate part, the top end of the ring plate part is provided with the top plate part, the inner wall of the ring plate part is provided with a pressing component, the pressing component is used for pressing down the diaphragm from the top, the bottom end of the ring plate part is provided with a lower positioning component, the center of the top plate part is provided with an opening through which the ejector pin penetrates, an upper positioning component is arranged inside the opening, and the upper positioning component and the lower positioning component alternately perform locking action; the upper positioning assembly is used for fixing the upper clamp and the thimble into a whole, and the lower positioning assembly is used for fixing the upper clamp and the lower clamp into a whole.

Furthermore, the compressing assembly comprises a pressing plate and a spring, the inner wall of the annular plate part is provided with chutes distributed in an annular array manner, the pressing plate is slidably mounted inside the chutes, the spring is arranged at the bottom of the pressing plate, and the spring is embedded in the chutes.

Furthermore, the upper positioning assembly comprises a first positioning strip and a first socket, the inner wall of the opening is provided with the first positioning strip distributed in an annular array, the first socket is arranged at the bottom end of the thimble, the first positioning strip is inserted into the first socket from the top in a matched mode, the side cross section of the first positioning strip is in a shape of a Chinese character 'ji', and the first positioning strip and the first socket are clamped and positioned or positioned in a magnetic adsorption mode.

Furthermore, the bottom end of the thimble is of a hemispherical structure, and the first socket is located at the top of the hemispherical structure.

Furthermore, the lower positioning assembly comprises second positioning strips and a second socket, the second positioning strips are arranged on the bottom surface of the annular plate part in an annular array mode, the second socket is arranged on the outer wall of the lower fixture, the second positioning strips are inserted into the second socket, and the second positioning strips and the second socket are clamped and positioned or positioned in a magnetic adsorption mode.

A puncturing method for testing the puncturing strength of a lithium battery diaphragm comprises the following steps:

s1, placing a diaphragm to be tested;

cutting a diaphragm sample according to the size of the outer diameter of the clamp;

placing the diaphragm sample on the top end of the lower clamp;

setting test parameters;

s2, pressing the diaphragm;

the thimble moves downwards, and then drives the upper clamp on the outer wall of the bottom end of the thimble to move downwards;

the pressing plate is attached to the top surface of the diaphragm sample, the pressing plate slides upwards along the sliding groove under the stress and compresses the spring, and meanwhile, the pressing plate presses the diaphragm sample downwards to eliminate a gap between the diaphragm sample and the lower clamp;

in the process of sliding upwards on the pressing plate, starting the vacuum mechanism, pumping out air in the air guide hole by the vacuum mechanism, and fixing the diaphragm sample at the top end of the lower clamp by negative pressure;

the pressing plate slides upwards to the topmost end, the spherical head part of the thimble does not apply force to the diaphragm, the lower positioning assembly locks to connect the upper clamp and the lower clamp into a whole, and the upper positioning assembly unlocks to separate the upper clamp from the thimble;

s3, puncture test;

the thimble slides downwards at a constant speed according to the set parameters until the diaphragm is pierced;

after the puncture action is finished, the thimble is separated from the lower clamp, and when the thimble moves to the position of the top surface of the diaphragm, the lower positioning assembly is unlocked and the upper positioning assembly is locked;

the thimble drives the upper clamp to move upwards together, and the upper clamp is separated from the lower clamp.

The invention has the beneficial effects that: the diaphragm is stressed more uniformly when placed on the lower fixture, the laminating effect of the diaphragm and the fixture is better, and the accuracy and the repeatability of the test are improved.

Drawings

FIG. 1 is a schematic structural diagram of a puncturing device for testing the puncturing strength of a lithium battery diaphragm;

FIG. 2 shows an overall top view schematic of the lower clamp of the present invention;

FIG. 3 shows a schematic view of the upper clamp structure of the present invention;

FIG. 4 shows an enlarged schematic view at A of FIG. 1 of the present invention;

FIG. 5 is an enlarged schematic view of FIG. 1 at B of the present invention;

shown in the figure: 1. detecting the bracket; 11. an upper base; 12. a guide bar; 13. a lower base; 2. a slide base; 3. a thimble; 31. a first socket; 311. a first electromagnet; 4. an upper clamp; 41. opening a hole; 411. a first positioning bar; 42. a chute; 421. a spring; 422. pressing a plate; 43. a second positioning bar; 5. a diaphragm; 6. a lower clamp; 61. an air vent; 62. a second socket; 621. a second electromagnet; 7. and (4) a vacuum mechanism.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the puncturing device for testing the puncturing strength of the lithium battery diaphragm comprises adetection bracket 1, wherein thedetection bracket 1 comprises anupper base 11, aguide rod 12 and alower base 13; aguide rod 12 is vertically arranged on the surface of thelower base 13, the top end of theguide rod 12 is provided with anupper base 11, a slidingseat 2 is slidably arranged on the outer wall of theguide rod 12, and athimble 3 is vertically arranged at the center of the bottom surface of the slidingseat 2; the sliding seat slides up and down along the guide rod to drive the thimble to move along with the guide rod;

anupper clamp 4 is detachably mounted on the outer wall of the bottom end of thethimble 3, alower clamp 6 is mounted at the bottom of theupper clamp 4, adiaphragm 5 with the same outer diameter is arranged at the top end of thelower clamp 6, thediaphragm 5 is embedded in theupper clamp 4,air guide holes 61 distributed in an annular array are formed in thelower clamp 6, openings at the top ends of theair guide holes 61 are arranged at the bottom of thediaphragm 5, openings at the bottom ends of theair guide holes 61 are communicated to avacuum mechanism 7, and thevacuum mechanism 7 is used for adsorbing thediaphragm 5 under negative pressure; the air guide hole is utilized to perform nondestructive positioning on the diaphragm, so that the deviation of the upper fixture during installation is avoided, the positioning strength is improved, the puncture strength of the lithium ion battery diaphragm can be conveniently and quickly tested, and the accuracy and the reappearance of the test under the conditions of good laminating effect and uniform stress of the fixture can be ensured.

As shown in fig. 1 and 3, theupper fixture 4 includes a ring plate portion and a top plate portion, the top end of the ring plate portion is provided with the top plate portion, the inner wall of the ring plate portion is provided with a pressing component for pressing down themembrane 5 from the top, the bottom end of the ring plate portion is provided with a lower positioning component, the center of the top plate portion is provided with anopening 41 for passing the thimble, an upper positioning component is arranged inside theopening 41, and the upper positioning component and the lower positioning component alternately perform locking actions; the upper positioning assembly is used for fixing theupper clamp 4 and thethimble 3 into a whole, and the lower positioning assembly is used for fixing theupper clamp 4 and thelower clamp 6 into a whole; the diaphragm can be positioned by utilizing the compressing assembly, the upper positioning assembly can realize vertical assembly of the upper clamp together with the thimble in a downward moving manner, independent installation is not needed, the assembly precision is ensured, the diaphragm is prevented from deviating in the assembly process, meanwhile, vertical compression assembly can also be realized, and the problem that the diaphragm is easy to deviate in the screwing and buckling processes is solved;

the setting of lower locating component can avoid the anchor clamps atress to rotate, also can guarantee simultaneously the puncture in-process, goes up anchor clamps and anchor clamps are fixed as an organic whole down, improves the location intensity of diaphragm, avoids the puncture in-process simultaneously, and the thimble receives the power except that the diaphragm, guarantees the puncture and detects the precision.

As shown in fig. 4, the pressing assembly includes apressing plate 422 andsprings 421, the inner wall of the ring plate portion is provided withsliding grooves 42 distributed in an annular array, thepressing plate 422 is slidably mounted inside thesliding grooves 42, the bottom of thepressing plate 422 is provided with thesprings 421, and thesprings 421 are embedded in thesliding grooves 42; the upward sliding of the pressure plate compresses the spring, causing the pressure plate to press the diaphragm in the opposite direction.

As shown in fig. 5, the upper positioning assembly includes afirst positioning bar 411 and afirst socket 31, the inner wall of theopening 41 is provided with thefirst positioning bar 411 distributed in an annular array, thefirst socket 31 is disposed at the bottom end of thethimble 3, thefirst positioning bar 411 is inserted into thefirst socket 31 from the top in a matching manner, and the side cross section of thefirst positioning bar 411 is 7-shaped; thefirst positioning bar 411 and thefirst socket 31 are clamped and positioned or positioned by magnetic adsorption; the cooperation that utilizes first locating strip and second socket can realize the rapid Assembly location, and 7 font structures just peg graft from upper portion, can guarantee that thimble and last anchor clamps separation when moving downwards, can hold up anchor clamps when moving upwards.

Thefirst positioning bar 411 is internally provided with a magnetic material, the bottom end inside thefirst socket 31 is provided with afirst electromagnet 311, and thefirst electromagnet 311 and thefirst positioning bar 411 are fixed in an adsorption manner.

The bottom end of thethimble 3 is of a hemispherical structure, and thefirst socket 31 is located at the top of the hemispherical structure.

The lower positioning assembly comprises a second positioning bar 433 and asecond socket 62, the second positioning bar 433 is arranged on the bottom surface of the annular plate part in an annular array, thesecond socket 62 is arranged on the outer wall of thelower clamp 6, and the second positioning bar 433 is inserted into thesecond socket 62; the second positioning strip 433 and thesecond socket 62 are clamped and positioned or positioned by magnetic adsorption; the cooperation of the second positioning strip and the second socket can realize two functions of autorotation prevention and separation prevention;

the second location strip, second socket and air guide hole all are 5 that the annular array distributes.

The second positioning bar 433 is provided with a magnetic material inside, thesecond socket 62 is provided with asecond electromagnet 621 inside, and the second positioning bar 433 is fixed to thesecond electromagnet 621 in an adsorption manner.

The puncturing method for testing the puncturing strength of the lithium battery diaphragm comprises the following steps:

s1, placing a diaphragm to be tested;

cutting a diaphragm sample according to the size of the outer diameter of the clamp;

placing the diaphragm sample on the top end of the lower clamp;

setting test parameters; the puncture speed is 50 mm/min, and the puncture needle displacement is 7 mm;

s2, pressing the diaphragm;

thethimble 3 moves downwards to drive theupper clamp 4 on the outer wall of the bottom end of the thimble to move downwards;

thepressing plate 422 is attached to the top surface of the diaphragm sample, thepressing plate 422 is forced to slide upwards along the slidinggroove 42 and compress thespring 421, and meanwhile, thepressing plate 422 presses the diaphragm sample downwards to eliminate the gap between the diaphragm sample and thelower clamp 6; the process is used for further compressing the diaphragm and eliminating gaps so as to ensure the negative pressure fixing strength of the next step, if the gaps exist, the diaphragm cannot be adsorbed by the negative pressure sufficiently, and meanwhile, the diaphragm is prevented from displacing in the subsequent action;

in the process of sliding thepressing plate 422 upwards, thevacuum mechanism 7 is started, thevacuum mechanism 7 pumps out air in theair guide hole 61, and the diaphragm sample is fixed at the top end of thelower clamp 6 by negative pressure; the vacuum mechanism can suck away air in the air guide hole, so that the diaphragm can be adsorbed at the top end of the lower clamp under negative pressure, and the diaphragm is prevented from protruding upwards or deviating during puncture; the vacuum mechanism is exemplarily selected from a micro diaphragm vacuum pump;

thepressing plate 422 slides up to the topmost end, the spherical head part of thethimble 3 does not apply force to thediaphragm 5, the lower positioning assembly locks to connect theupper clamp 4 and thelower clamp 6 into a whole, and the upper positioning assembly unlocks to separate theupper clamp 4 from thethimble 3; when the pressing plate is completely pressed, the assembly of the upper clamp and the lower clamp is completed, the positioning process of the diaphragm is completed, at the moment, the lower positioning assembly needs to be separated, the locking is firstly carried out, the unlocking is carried out after the upper positioning assembly, and therefore the thimble can be ensured not to be subjected to the reverse force from the upper clamp when continuously moving downwards, and the puncture precision is ensured; if the positioning bar and the socket adopt a clamping mode, a worker presses a corresponding unlocking chuck, and if the positioning bar and the socket adopt an electromagnetic adsorption mode, a corresponding control power supply button is pressed;

s3, puncture test;

thethimble 3 applies force to puncture thediaphragm 5;

after the puncture action is finished, thethimble 3 is separated from thelower clamp 6, and when thethimble 3 moves to the position of the top surface of the diaphragm, the lower positioning assembly is unlocked and the upper positioning assembly is locked;

thethimble 3 drives theupper clamp 4 to move upwards together, and theupper clamp 4 is separated from thelower clamp 6. Three verification tests are carried out by the method to obtain the following data;

according to the data, the tensile strength obtained by three tests is not much different, the reliability and the detection precision of the data are greatly improved by the improved diaphragm positioning method, and the data cannot fluctuate greatly.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (7)

1. The utility model provides a test lithium cell diaphragm puncture strength's piercing depth which characterized in that: the device comprises a detection bracket (1), wherein the detection bracket (1) comprises an upper base (11), a guide rod (12) and a lower base (13); a guide rod (12) is vertically arranged on the surface of the lower base (13), the top end of the guide rod (12) is provided with an upper base (11), a sliding seat (2) is slidably arranged on the outer wall of the guide rod (12), an ejector pin (3) is vertically arranged at the center of the bottom surface of the sliding seat (2), an upper clamp (4) is detachably mounted on the outer wall of the bottom end of the thimble (3), a lower clamp (6) is mounted at the bottom of the upper clamp (4), the top end of the lower clamp (6) is provided with a diaphragm (5) with the same outer diameter, the diaphragm (5) is embedded in the upper clamp (4), the lower clamp (6) is internally provided with air guide holes (61) distributed in an annular array, the top end openings of the air guide holes (61) are arranged at the bottom of the diaphragm (5), the bottom end openings of the air guide holes (61) are communicated to a vacuum mechanism (7), and the vacuum mechanism (7) is used for adsorbing the diaphragm (5) in a negative pressure mode.

2. The puncture device for testing the puncture strength of the lithium battery diaphragm according to claim 1, characterized in that: the upper clamp (4) comprises a ring plate part and a top plate part, the top end of the ring plate part is provided with the top plate part, the inner wall of the ring plate part is provided with a pressing component, the pressing component is used for pressing down a diaphragm (5) from the top, the bottom end of the ring plate part is provided with a lower positioning component, the center of the top plate part is provided with an opening (41) for a thimble to penetrate through, an upper positioning component is arranged inside the opening (41), and the upper positioning component and the lower positioning component are alternately locked; the upper positioning assembly is used for fixing the upper clamp (4) and the thimble (3) into a whole, and the lower positioning assembly is used for fixing the upper clamp (4) and the lower clamp (6) into a whole.

3. The puncture device for testing the puncture strength of the lithium battery diaphragm according to claim 2, characterized in that: the pressing assembly comprises a pressing plate (422) and springs (421), the inner wall of the ring plate part is provided with sliding grooves (42) distributed in an annular array mode, the pressing plate (422) is slidably mounted inside the sliding grooves (42), the springs (421) are arranged at the bottoms of the pressing plates (422), and the springs (421) are embedded into the sliding grooves (42).

4. The puncture device for testing the puncture strength of the lithium battery diaphragm according to claim 2, characterized in that: go up locating component and include first locating strip (411), first socket (31), the inner wall of trompil (41) is equipped with first locating strip (411) that the annular array distributes, the bottom of thimble (3) is located in first socket (31), first locating strip (411) are followed the top cooperation cartridge and are in first socket (31), the side cross-section of first locating strip (411) is (7) font, clamp the location or the magnetic adsorption location between first locating strip (411) and first socket (31).

5. The puncturing device for testing the puncturing strength of the lithium battery diaphragm according to claim 4, wherein: the bottom end of the thimble (3) is of a hemispherical structure, and the first socket (31) is located at the top of the hemispherical structure.

6. The puncture device for testing the puncture strength of the lithium battery diaphragm according to claim 2, characterized in that: the lower positioning assembly comprises a second positioning strip (433) and a second socket (62), the second positioning strip (433) is arranged on the bottom surface of the annular plate part in an annular array mode, the second socket (62) is arranged on the outer wall of the lower clamp (6), the second positioning strip (433) is inserted into the second socket (62), and the second positioning strip (433) and the second socket (62) are clamped, positioned or positioned in a magnetic adsorption mode.

7. A puncturing method for testing the puncturing strength of a lithium battery diaphragm is characterized in that: the puncturing device according to claim 1, wherein the puncturing method comprises the following steps:

s1, placing a diaphragm to be tested;

cutting a diaphragm sample according to the size of the outer diameter of the clamp;

placing the diaphragm sample on the top end of the lower clamp;

setting test parameters;

s2, pressing the diaphragm;

the thimble (3) moves downwards to drive the upper clamp (4) on the outer wall of the bottom end of the thimble to move downwards;

the pressing plate (422) is attached to the top surface of the diaphragm sample, the pressing plate (422) is stressed to slide upwards along the sliding groove (42) and compress the spring (421), and meanwhile, the pressing plate (422) presses the diaphragm sample downwards to eliminate a gap between the diaphragm sample and the lower clamp (6);

in the process of sliding the pressing plate (422) upwards, the vacuum mechanism (7) is started, the vacuum mechanism (7) pumps air in the air guide hole (61), and the diaphragm sample is fixed at the top end of the lower clamp (6) by negative pressure;

the pressing plate (422) slides upwards to the topmost end, the spherical head part of the ejector pin (3) does not apply force to the diaphragm (5), the lower positioning assembly locks to connect the upper clamp (4) and the lower clamp (6) into a whole, and the upper positioning assembly unlocks to separate the upper clamp (4) from the ejector pin (3);

s3, puncture test;

the thimble (3) slides downwards at a constant speed according to the set parameters until the diaphragm (5) is pierced;

after the puncture action is finished, the thimble (3) is separated from the lower clamp (6), and when the thimble (3) moves to the position of the top surface of the diaphragm, the lower positioning assembly is unlocked and the upper positioning assembly is locked;

the thimble (3) drives the upper clamp (4) to move upwards together, and the upper clamp (4) is separated from the lower clamp (6).

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