Lithium battery test fixture

Abstract

The utility model relates to a lithium battery test fixture which comprises a clamping plate A, a clamping plate B and a clamping plate C. The four ends of the clamping plate A and the four ends of the clamping plate C are fixedly connected with fixing screws through nuts respectively, the clamping plate B is movably installed between the clamping plate A and the clamping plate C through a spring, and a scale workpiece for testing the distance between the clamping plate B and the clamping plate C is further installed between the clamping plate B and the clamping plate C. After a battery is placed between the clamping plate A and the clamping plate B, the nuts at the pressing screws are screwed down according to the preset pressure requirement, the pressing amount of the four corners is read by referring to the graduated scale, and the effect of uniform pressure of the four corners is achieved. The scale workpiece can effectively improve the consistency of the pressing amount of the clamping plate, so that all parts of the tested battery are uniformly pressed, and the accuracy of a test result is improved. Therefore, the clamp can reserve swelling capacity for the battery, simulates the stress working condition of the battery during testing, and releases the stress caused by battery expansion.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery testing, in particular to a lithium battery testing fixture. Background Technique

[0002] At present, due to the advantages of high energy density and long cycle life, lithium batteries are widely used in the fields of consumer electronics, energy storage, and new energy vehicles. For lithium batteries, steel shells, aluminum shells, or aluminum-plastic films are generally used as the outer shells. During the manufacturing process, a series of tests need to be carried out on the batteries to understand the actual performance level of the batteries. Taking the lithium battery cycle test as an example, during the cycle test of the battery, the gas continuously generated inside the battery and the continuously expanding electrode sheets may cause different degrees of deformation of the battery outer shell. As the battery expansion increases, the contact between the active substances in the battery becomes worse, and the ohmic resistance increases, resulting in the attenuation of the battery's cycle life.

[0003] In the conventional test method, a fixture is required to simulate the stress condition of a single cell in the module. The existing fixtures are generally fixtures with a fixed spacing. The fixture does not reserve an expansion amount for the battery, and the simulated stress condition is single, and the stress caused by the battery expansion cannot be released. Therefore, the present invention aims to propose a lithium battery testing fixture to meet the requirement of testing a single cell under the actual stress mode. Content of the Utility Model

[0004] The purpose of the utility model is to provide a lithium battery testing fixture to solve the problems encountered in the above background technique.

[0005] To achieve the above purpose, the technical solution of the utility model is as follows:

[0006] In a solution of an embodiment, a lithium battery testing fixture includes a clamping plate A, a clamping plate B, and a clamping plate C. The four ends of the clamping plate A and the four ends of the clamping plate C are respectively fixedly connected to the fixing screw through nuts. The clamping plate B is movably installed between the clamping plate A and the clamping plate C through a spring, and a scale workpiece for testing the distance between the two is also installed between the clamping plate B and the clamping plate C.

[0007] In the above solution, an elastic rubber pad is respectively fixed on the top surface of the clamping plate A and the bottom surface of the clamping plate B, and the plane of the elastic rubber pad is larger than the contact surface of the test battery. As a preferred solution, the elastic rubber pad is any one of a polycarbonate film, a polyolefin film, and a polyurethane film.

[0008] In the above solution, temperature sensors are respectively arranged on the top surface of the clamping plate A and the bottom surface of the clamping plate B. As a preferred solution, at least one temperature sensor is provided, and the temperature sensor protrudes from the surface of the elastic rubber pad. Further, the probe bottoms of the temperature sensors are elastically connected to the top surface of the clamping plate A and the bottom surface of the clamping plate B respectively.

[0009] In the above solution, a threaded counterbore is provided on the top surface of the clamping plate B. A pressing screw rod is fixed in the clamping plate C through a nut, and the bottom of the pressing screw rod extends into the threaded counterbore. Further, the spring is sleeved on the outer periphery of the extended part at the bottom of the pressing screw rod and supports the clamping plate B and the clamping plate C.

[0010] In the above solution, a positioning groove is provided on the top surface of the clamping plate B. The graduated workpiece is installed in the positioning groove. The body of the graduated workpiece penetrates through the plate body of the clamping plate C and extends to the top of the clamping plate C. As a preferred solution, during installation, scale lines are provided on the outer side of the body of the graduated workpiece, and the height of each graduated workpiece is flush, that is, the "0" scale is at the same position.

[0011] In the solution of another embodiment, a lithium battery test fixture includes a clamping plate A, a clamping plate B, and a clamping plate C. The four ends of the clamping plate A and the four ends of the clamping plate C are respectively fixedly connected to the fixed screw rod through nuts. The clamping plate B is movably installed between the clamping plate A and the clamping plate C through a connecting rod. A pressure sensor is provided on the top of the clamping plate A, and a driving device for driving the clamping plate B to move up and down is installed on the top of the clamping plate C; the driving device is used to receive the signal of the pressure sensor and adjust the pressure in real time.

[0012] Similar to the solution in the previous embodiment, in order to protect the lithium battery, an elastic rubber pad is respectively fixed on the top surface of the clamping plate A and the bottom surface of the clamping plate B. The plane of the elastic rubber pad is larger than the contact surface of the test battery; the elastic rubber pad is any one of a polycarbonate film, a polyolefin film, and a polyurethane film.

[0013] Specifically, a through hole is provided in the middle of the top of the clamping plate C. The telescopic rod of the driving device extends into the through hole and is connected to a pressure dividing plate; four hinge seats are arranged at the four ends of the bottom of the clamping plate C along the diagonal direction. Four sliding grooves are arranged along the diagonal direction on the top surface of the clamping plate B. Sliders are installed in the sliding grooves. One side of the slider is hinged to the pressure dividing plate through a connecting rod, and the other side of the slider is hinged to the hinge seat through a connecting rod.

[0014] As a preferred solution, the slider is of a wedge-shaped structure. An avoidance groove is provided on the top of the slider, and rollers slidably connected to the sliding groove are installed at the bottom of the slider. During implementation, two rotating shafts are respectively provided on both sides of the pressure dividing plate, and the installation positions of the rotating shafts are arranged according to the diagonal direction of the bottom of the clamping plate C.

[0015] Compared with the prior art, the beneficial effects of the present utility model are:

[0016] In the first solution, after the battery is placed between clamping plate A and clamping plate B, according to the preset pressure requirement, tighten the nut at the compression screw. The compression amount at the four corners is referred to the reading on the scale, achieving the effect of uniform pressure at the four corners. The graduated workpiece can effectively improve the consistency of the clamping amount of the clamping plate, making the pressure on each part of the tested battery uniform and improving the accuracy of the test results. The graduated workpiece can simplify the operation of changing the fixture type. The dimensional changes of different models of batteries are intuitively reflected on the scale of the graduated workpiece, and the distance between the fixtures is adjusted accordingly. Therefore, this fixture can reserve an expansion amount for the battery, simulate the stress condition of the battery during testing, and release the stress caused by the battery expansion.

[0017] In the second solution, in this solution, a pressure sensor is set on the battery contact surface of clamping plate A to monitor the pressure of the battery on the pressure plate in real time and feedback to the driving device for adjustment (the force is mutual). Using the pressure sensor to monitor the pressure of the clamping plate on the battery in real time and transmit it to the driving device to adjust the pressure in real time can ensure that the battery is always tested within a reasonable pressure range. Compared with simply relying on tightening the nut to provide pressure, the pressure sensor can make the clamping plate pressure concrete, accurately reach the designed pressure, and improve the accuracy of the test under the premise of accurate pressure. The multi-point contact of the pressurizing mechanism composed of eight inner and outer connecting rods and the driving device can make the tested battery more evenly stressed and the test state more stable.

[0018] The purpose of the present utility model is to propose a lithium-ion battery test fixture, which can monitor the expansion force of the battery in real time and adjust the clamping force of the clamping plate in real time to ensure that the battery is always tested within a reasonable pressure range, and can improve the problems of the decline of the battery cycle life and inaccurate testing caused by the expansion stress that cannot be released during the battery testing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The disclosure of the present utility model will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the protection scope of the present utility model. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0020] Figure 1 is the overall structural schematic diagram of the present utility model in Embodiment 1;

[0021] Figure 2 is Figure 1 front view;

[0022] Figure 3 is the bottom surface structural schematic diagram of clamping plate B in Embodiment 2 or 3 of the present utility model;

[0023] Figure 4 is the top surface structural schematic diagram of clamping plate B in Embodiment 2 or 3 of the present utility model;

[0024] Figure 5This is the overall structure schematic diagram of the present utility model in Embodiment 4;

[0025] Figure 6 This is the exploded view of the present utility model in Embodiment 4;

[0026] Figure 7 This is the structure schematic diagram of the slider of the present utility model in Embodiment 5;

[0027] Figure 8 This is the structure schematic diagram of the driving device of the present utility model in Embodiment 5;

[0028] Figure 9 This is the structure schematic diagram of the clamping plate C of the present utility model in Embodiment 5.

[0029] Reference numerals in the figure: 1 - clamping plate A; 11 - elastic rubber pad; 12 - temperature sensor; 13 - pressure sensor; 2 - clamping plate B; 21 - spring; 22 - fixing screw; 23 - through hole; 24 - threaded counterbore; 25 - positioning groove; 26 - chute; 27 - slider; 28 - avoidance groove; 29 - roller; 3 - clamping plate C; 31 - pressing screw; 32 - graduated workpiece; 33 - hinge seat; 34 - connecting rod; 35 - through hole; 4 - driving device; 41 - pressure dividing plate; 42 - rotating shaft. Detailed implementation manners

[0030] In order to make the technical means, creative features, achieved purposes and functions of the present utility model easy to understand, the present utility model will be further described in detail below with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present utility model in a schematic manner, so they only show the relevant components of the present utility model.

[0031] According to the technical solution of the present utility model, without changing the essential spirit of the present utility model, those of ordinary skill in the art can propose various structural forms and implementation manners that can be mutually replaced. Therefore, the following detailed implementation manners and the accompanying drawings are only exemplary descriptions of the technical solution of the present utility model, and should not be regarded as the whole of the present utility model or as a limitation or restriction on the technical solution of the present utility model.

[0032] The technical solution of the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Embodiment 1, as Figure 1 and Figure 2As shown in the figure, a lithium battery test fixture includes clamping plate A1, clamping plate B2, and clamping plate C3. Generally, materials with a relatively large Young's modulus, such as steel plates, aluminum plates, copper plates, etc., are selected for each clamping plate. Clamping plate A1, clamping plate B2, and clamping plate C3 are arranged parallel to each other in sequence. Threaded through holes are provided at the four corners of clamping plate A1 and clamping plate C3 to install and fix the fixing screw 22. Through holes 23 are provided at the four corners of clamping plate B2, and the fixing screw 22 slides within the through hole 23. The positions of the holes in each clamping plate correspond to each other. After respectively fixing the four ends of clamping plate A1 and the four ends of clamping plate C3 to the fixing screw 22 through nuts, nuts are provided on both sides of the threaded through holes provided at the four corners of clamping plate A1 and clamping plate C3 to lock each clamping plate and the fixing screw 22.

[0034] Clamping plate B2 is movably installed between clamping plate A1 and clamping plate C3 through a spring 21. A scale workpiece 32 for measuring the distance between the two is also installed between clamping plate B2 and clamping plate C3. The scale workpiece 32 can be a cylinder with scales or a scale ruler. Four positioning grooves 25 are provided outside the positions of the through holes 23 at the top surface and four corners of clamping plate B2 for installing four scale rulers. Through holes corresponding to the scale ruler positions are provided on clamping plate C3 for the scale rulers to pass through. The number of scale rulers can be set to 2 - 4 according to needs.

[0035] Specifically, positioning grooves 25 are provided on the top surface of clamping plate B2. The scale workpiece 32 is installed in the positioning grooves 25. The body of the scale workpiece 32 penetrates through the plate body of clamping plate C3 and extends to the top of clamping plate C3. The intersection line of the scale on the top surface of clamping plate C3 and the scale of the scale workpiece 32 is the reading line. As a preferred solution, during installation, scale lines are provided on the outer side of the body of the scale workpiece 32, and the heights of each scale workpiece 32 are flush, that is, the "0" scale is in the same position, so as to ensure the consistency of the pressing amount at each corner during battery testing.

[0036] After the battery is placed between clamping plate A1 and clamping plate B2, according to the preset pressure requirement, the nuts at the pressing screw are tightened, and the pressing amount at the four corners is referred to the reading of the scale ruler to achieve the effect of uniform pressure at the four corners. The scale workpiece 32 can effectively improve the consistency of the clamping amount of the clamping plate, make the pressure on each part of the tested battery uniform, and improve the accuracy of the test results. The scale workpiece 32 can simplify the operation of changing the fixture type. The size change of different types of batteries is directly reflected on the scale of the scale workpiece 32, and the distance between the fixtures is adjusted accordingly.

[0037] Embodiment 2: On the basis of Embodiment 1, an elastic rubber pad 11 is respectively fixed on the top surface of clamping plate A1 and the bottom surface of clamping plate B2. The plane of the elastic rubber pad 11 is larger than the contact surface of the tested battery. An elastic rubber pad 11 is provided between clamping plate A1 and clamping plate B2, and there is a certain amount of compression buffer space. During the test process, when the battery expands and squeezes the elastic rubber pad 11 to release pressure, the clamping force of the clamping plate can be maintained within the preset range.

[0038] As a preferred solution, the elastic rubber pad 11 is any one of a polycarbonate film, a polyolefin film, and a polyurethane film. The centers of the elastic rubber pad 11, the clamping plate, and the test battery coincide at one point, and the area of the elastic rubber pad 11 is larger than the large surface of the test battery. A hole is reserved in the central part of the elastic rubber pad 11 for arranging the temperature sensor 12. The deformation amount of the elastic rubber pad 11 needs to be equivalent to the maximum deformation amount of the battery to ensure that the elastic rubber pad 11 can fully buffer the pressure released by the expansion of the battery, so as to keep the clamping force of the clamping plate within a preset range. Optionally, the size specifications of the elastic rubber pad are selected according to the deformation amounts of different batteries.

[0039] Please refer to Figure 1 and Figure 3 , by respectively arranging temperature sensors 12 on the top surface of the clamping plate A1 and the bottom surface of the clamping plate B2, the arranged temperature sensors 12 can monitor the temperature change of the test battery in real time, give an alarm prompt for the battery with abnormal temperature, and avoid the risk of thermal runaway caused by the deterioration of the battery performance due to the test. As a preferred solution, at least one temperature sensor 12 is provided, and the temperature sensor 12 protrudes from the surface of the elastic rubber pad 11 for directly contacting the battery to accurately test the actual temperature of the battery.

[0040] Furthermore, the bottom parts of the probes of the temperature sensors 12 are elastically connected to the top surface of the clamping plate A1 and the bottom surface of the clamping plate B2 respectively. The temperature sensors 12 are arranged at the middle positions of the opposite surfaces of the clamping plate A1 and the clamping plate B2. Springs are arranged behind the probes of the temperature sensors 12 to buffer the extrusion force generated by the expansion of the battery on the probes and avoid damage to the probes. The number of the temperature sensors 12 can be selected according to the temperature acquisition requirements of the test battery.

[0041] Example 3, on the basis of Example 1, please refer to Figure 4 , a threaded counterbore 24 is formed on the top surface of the clamping plate B2, and a pressing screw 31 is fixed in the clamping plate C3 through a nut. The bottom of the pressing screw 31 extends into the threaded counterbore 24. Furthermore, a spring 21 is sleeved on the outer periphery of the extended part at the bottom of the pressing screw 31 to support the clamping plate B2 and the clamping plate C3. Springs 21 are arranged on the non-battery contact surface of the clamping plate B2 and the opposite surface of the clamping plate C3, and are sleeved on the pressing screw 31 to provide a clamping force and have a certain elastic effect to match the deformation size after the battery expands. The spring 21 here is a high elastic coefficient spring during implementation to provide sufficient clamping force.

[0042] Example 4, please refer to Figure 5 and Figure 6, A lithium battery test fixture, including clamping plate A1, clamping plate B2 and clamping plate C3. Generally, materials with a relatively large Young's modulus are selected for each clamping plate, such as steel plates, aluminum plates, copper plates, etc. for production. Clamping plate A1, clamping plate B2, and clamping plate C3 are arranged parallel and opposite to each other in sequence. Threaded through holes are provided at the four corners of clamping plate A1 and clamping plate C3 to install and fix the screw rod 22. Through holes 23 are provided at the four corners of clamping plate B2, and the fixed screw rod 22 slides within the through holes 23, with the positions of the holes in each clamping plate corresponding to each other. After respectively fixing the four ends of clamping plate A1 and the four ends of clamping plate C3 to the fixed screw rod 22 through nuts, nuts are provided on both sides of the threaded through holes provided at the four corners of clamping plate A1 and clamping plate C3 to lock each clamping plate and the fixed screw rod 22.

[0043] Clamping plate B2 is movably installed between clamping plate A1 and clamping plate C3 through a connecting rod 34, and the connecting rod 34 plays a role of movable support here. During implementation, threads are provided at both ends of the fixed screw rod 22, and the thread length is approximately 1 / 5 of the overall length of the fixed screw rod 22. The middle section is a smooth section for the sliding of clamping plate B2 during pressure adjustment.

[0044] A pressure sensor 13 is provided on the top of clamping plate A1. The pressure sensor 13 is preferably installed in the middle position to monitor the pressure of the battery on clamping plate A1 and clamping plate B2 in real time and feedback it to the driving device 4 (the action of force is mutual). Generally, a piezoresistive pressure sensor is used during the implementation of the pressure sensor. The pressure sensor 13 coincides with the center of the test battery (generally, the expansion amount at the center of the battery is the largest), and there is a more precise monitoring requirement for the battery expansion. A driving device 4 for driving clamping plate B2 to move up and down is installed on the top of clamping plate C3. The driving device 4 can select a cylinder or an oil cylinder, and it is preferably made of a cylinder. The driving device 4 is used to receive the signal of the pressure sensor 13 and adjust the pressure in real time.

[0045] An elastic rubber pad 11 is respectively fixed on the top surface of clamping plate A1 and the bottom surface of clamping plate B2. The plane of the elastic rubber pad 11 is larger than the contact surface of the test battery. There is a certain amount of compression buffer space. During the test process, the battery expansion squeezes the elastic rubber pad 11 to release pressure, and the clamping force of the clamping plate can be maintained within a preset range. The elastic rubber pad 11 is any one of a polycarbonate film, a polyolefin film, and a polyurethane film. The pressure sensor 13 is provided with an opening in the middle of the elastic rubber pad 11 to accommodate the pressure sensor 13. The probe height of the pressure sensor 13 is flush with the elastic rubber pad 11, and the number of pressure sensors 13 can be selected as one or more.

[0046] Embodiment 5. On the basis of Embodiment 4, a through hole 35 is provided in the middle of the top of the clamping plate C3. The telescopic rod of the driving device 4 extends into the through hole 35 and is connected with a pressure dividing plate 41. For example, the seat body of the air cylinder is installed on the top of the clamping plate C3, and the telescopic rod of the air cylinder extends into the through hole 35 and is fixedly connected with the pressure dividing plate 41. The pressure dividing plate 41 divides the downward pressure of the driving device 4 into pressures at 4 points, and evenly acts on the clamping plate B2 to press the battery to be tested.

[0047] Please refer to Figure 9 , four hinge seats 33 are arranged at the four ends of the bottom of the clamping plate C3 along the diagonal direction, and four sliding grooves 26 are arranged on the top surface of the clamping plate B2 along the diagonal direction. A slider 27 is installed in the sliding groove 26. One side of the slider 27 is hinged to the pressure dividing plate 41 through a connecting rod 34, and the other side of the slider 27 is hinged to the hinge seat 33 through a connecting rod 34.

[0048] As a preferred solution, please refer to Figure 7 , the slider 27 is of a wedge-shaped structure, and an avoidance groove 28 is provided at the top of the slider 27 for avoiding the movement range of the connecting rod 34 during articulated rotation. A roller 29 slidingly connected with the sliding groove 26 is installed at the bottom of the slider 27 for reducing the friction between the slider 27 and the sliding groove 26, so that it is easier to move under the push of the battery expansion force.

[0049] Please refer to Figure 8 , wherein, two rotating shafts 42 are respectively provided on both sides of the pressure dividing plate 41, and the installation positions of the rotating shafts 42 are arranged according to the diagonal direction of the bottom of the clamping plate C3. The rotating shafts 42 facilitate the rotation of the connecting rod 34 with the shaft hole. And for the convenience of the rotation of the connecting rod 34, structures similar to the rotating shafts 42 can also be provided on both sides of the top of the slider and in the hinge seat 33 to facilitate the movable support of the clamping plate B2 during the rotation process.

[0050] Combining the solutions of Embodiment 4 and 5, during operation: Since the driving device 4 is used to receive the signal of the pressure sensor 13 and adjust the pressure in real time, when the working end of the driving device 4 presses down, it pushes the connecting rod 34 to make the slider 27 slide towards the outside of the fixture. Due to the hinge restriction of the connecting rod 34 with the clamping plate C3, the horizontal force is offset, and the downward pressure in the vertical direction is retained to press the clamping plate B2, and then the battery to be tested is pressed; on the contrary, when the working end of the driving device 4 rises, it pulls the four inner connecting rods 34 to make the wedge-shaped slider 27 slide towards the center of the fixture. Due to the hinge restriction of the four outer connecting rods 34 with the clamping plate C3, the horizontal force is offset, and the upward force in the vertical direction is retained to loosen the clamping plate B2, and then the expansion force of the battery is released.

[0051] In this solution, a pressure sensor 13 is provided at the battery contact surface of the clamping plate A1 to monitor the pressure of the battery on the pressing plate in real time and feedback to the driving device 4 for adjustment (the action of force is mutual). Using the pressure sensor 13 to monitor the pressure of the clamping plate on the battery in real time and transmit it to the driving device 4 for real-time pressure adjustment can ensure that the battery is always tested within a reasonable pressure range. Compared with simply relying on screwing nuts to provide pressure, the pressure sensor 13 can make the clamping plate pressure visualized, accurately reach the designed pressure, and improve the test accuracy on the premise of accurate pressure. The eight inner and outer connecting rods 34 and the driving device 4 form a multi-point contact of the pressing mechanism, which can make the tested battery more evenly stressed and the test state more stable.

[0052] The utility model aims to propose a lithium-ion battery test fixture, which can monitor the expansion force of the battery in real time and adjust the clamping force of the clamping plate in real time to ensure that the battery is always tested within a reasonable pressure range, so as to improve the problems of the decline of the battery cycle life and inaccurate testing caused by the expansion stress that cannot be released during the battery testing process.

[0053] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the utility model. It should be understood that the above are only specific embodiments of the utility model and are not used to limit the protection scope of the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the utility model shall be included within the protection scope of the utility model.

Claims

1. A lithium battery test fixture, characterized in that: It includes clamping plate A (1), clamping plate B (2) and clamping plate C (3). Four ends of the clamping plate A (1) and four ends of the clamping plate C (3) are respectively fixedly connected to the fixed screw rod (22) through nuts. The clamping plate B (2) is movably installed between the clamping plate A (1) and the clamping plate C (3) through a spring (21). A scale workpiece (32) for testing the distance between the two is also installed between the clamping plate B (2) and the clamping plate C (3).

2. The lithium battery testing fixture according to claim 1, wherein: An elastic rubber pad (11) is respectively fixed on the top surface of the clamping plate A (1) and the bottom surface of the clamping plate B (2). The plane of the elastic rubber pad (11) is larger than the contact surface of the test battery. The elastic rubber pad (11) is any one of a polycarbonate film, a polyolefin film, and a polyurethane film.

3. The lithium battery test fixture according to claim 2, characterized in that: Temperature sensors (12) are respectively arranged on the top surface of the clamping plate A (1) and the bottom surface of the clamping plate B (2). At least one temperature sensor (12) is provided. The probe of the temperature sensor (12) protrudes from the surface of the elastic rubber pad (11). The bottom of the probe of the temperature sensor (12) is elastically connected to the top surface of the clamping plate A (1) and the bottom surface of the clamping plate B (2) respectively.

4. The lithium battery test fixture according to claim 1, wherein: A threaded counterbore (24) is formed on the top surface of the clamping plate B (2). A pressing screw rod (31) is fixedly installed in the clamping plate C (3) through a nut. The bottom of the pressing screw rod (31) extends into the threaded counterbore (24). The spring (21) is sleeved on the outer periphery of the extended part at the bottom of the pressing screw rod (31) and supports the clamping plate B (2) and the clamping plate C (3).

5. A lithium battery test fixture according to claim 1, characterized in that: A positioning groove (25) is formed on the top surface of the clamping plate B (2). The scale workpiece (32) is installed in the positioning groove (25). The body of the scale workpiece (32) penetrates through the plate body of the clamping plate C (3) and extends to the top of the clamping plate C (3). Scale lines are arranged on the outer side of the body of the scale workpiece (32). The heights of each scale workpiece (32) are flush, that is, the "0" scale is in the same position.

6. A lithium battery test fixture, characterized in that: It includes clamping plate A (1), clamping plate B (2) and clamping plate C (3). Four ends of the clamping plate A (1) and four ends of the clamping plate C (3) are respectively fixedly connected to the fixed screw rod (22) through nuts. The clamping plate B (2) is movably installed between the clamping plate A (1) and the clamping plate C (3) through a connecting rod (34). A pressure sensor (13) is arranged on the top of the clamping plate A (1). A driving device (4) for driving the clamping plate B (2) to move up and down is installed on the top of the clamping plate C (3). The driving device (4) is used to receive the signal of the pressure sensor (13) and adjust the pressure in real time.

7. The lithium battery test fixture according to claim 6, wherein: An elastic rubber pad (11) is respectively fixed on the top surface of the clamping plate A (1) and the bottom surface of the clamping plate B (2). The plane of the elastic rubber pad (11) is larger than the contact surface of the test battery. The elastic rubber pad (11) is any one of a polycarbonate film, a polyolefin film, and a polyurethane film.

8. The lithium battery test fixture according to claim 6, characterized in that: A through hole (35) is formed in the middle of the top of the clamping plate C (3), and the telescopic rod of the driving device (4) extends into the through hole (35) and is connected with a pressure dividing plate (41); four hinge seats (33) are arranged at the four ends of the bottom of the clamping plate C (3) along the diagonal direction, four sliding grooves (26) are arranged at the top surface of the clamping plate B (2) along the diagonal direction, a sliding block (27) is installed in the sliding groove (26), one side of the sliding block (27) is hinged to the pressure dividing plate (41) through a connecting rod (34), and the other side of the sliding block (27) is hinged to the hinge seat (33) through a connecting rod (34).

9. The lithium battery testing fixture according to claim 8, wherein: The sliding block (27) is of a wedge-shaped structure, an avoidance groove (28) is formed in the top of the sliding block (27), and a roller (29) which is slidably connected with the sliding groove (26) is installed at the bottom of the sliding block (27).

10. A lithium battery test fixture according to claim 8, characterized in that: Two rotating shafts (42) are respectively arranged on both sides of the pressure dividing plate (41), and the installation positions of the rotating shafts (42) are arranged according to the diagonal direction of the bottom of the clamping plate C (3).

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