End plate strength testing method and end plate strength testing device

Abstract

The invention relates to the technical field of end plate strength testing, in particular to an end plate strength testing method and an end plate strength testing device. The end plate strength testing method adopted by the end plate strength testing device comprises the following steps: drawing a coordinate curve of an expansion amount when a battery cell expands and a reaction force required for maintaining the battery cell in a normal state under the expansion amount; the end plate is fixed on the base frame; arranging the battery cell in the expanded state at one end of the end plate along the preset direction and abutting against the end plate, wherein the expansion direction of the battery cell is parallel to the preset direction; fixing a binding belt on the base frame and binding the binding belt outside the end face, far away from the battery cell, of the end plate in the preset direction; the battery cell is driven to move by a preset distance towards the direction close to the end plate in the preset direction; taking the preset distance as swelling capacity to be substituted into the coordinate curve to obtain a numerical value of the counter-acting force; the deformation quantity of the end plate in the preset direction is recorded, whether the end plate cracks or not is observed, the strength of the end plate is tested in the state that the stress condition of the end plate is truly simulated, and the testing effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of end plate strength testing, and in particular to an end plate strength testing method and an end plate strength testing device. Background Art

[0002] During the assembly process of the battery module, multiple cells need to be stacked in sequence, with buffering and insulating spacers added between the cells, and an end plate added to each end of the multiple cells along the stacking direction. By pre-pressing the cells along the stacking direction, the battery module length is shortened to a certain length. Then, a tie is tied around the periphery of the cells and the end plates. The pre-pressure is then released, allowing the tie to wrap around the end plates, thereby securing the cells and end plates. The grouped battery modules are then placed in a battery case, which has a fixing beam and bolts. The bolt holes in the end plates are coaxially arranged with the threaded holes in the fixing beams. The bolts secure the battery modules to the fixing beams of the battery case.

[0003] During the charge and discharge process, the battery cell undergoes volume changes due to the cell expansion force. The straps and end plates constrain the cell's volume expansion, thereby protecting the cell casing from excessive deformation and rupture, and safeguarding the battery module. When the cell expansion force exceeds the end plate's load-bearing capacity and the end plate structure fails, the cell will continue to expand unrestrained, ultimately leading to module failure and even more severe irreversible damage, such as internal short circuits and thermal runaway. With the continuous advancement of battery cell technology, cell energy density is increasing, and the resulting cell expansion force is increasing. Therefore, how to accurately and effectively evaluate the end plate's ability to withstand the cell expansion force has become a pressing issue. Summary of the Invention

[0004] The purpose of the present invention is to provide an end plate strength testing method and an end plate strength testing device to truly simulate the pressure exerted on the end plate when the battery cell expands and accurately test the strength of the end plate.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The end plate strength test method is used to clamp and fix the battery cell. The battery cell has a normal state that is the same as the production specifications and an expanded state after expansion. The end plate can provide a reaction force to the battery cell in the expanded state to keep the battery cell in the normal state. The end plate strength test method includes the following steps:

[0007] S1. plotting a coordinate curve of the expansion amount of the battery cell when it expands and the reaction force required to maintain the battery cell in a normal state under the expansion amount;

[0008] S2, fixing the end plate on the base frame;

[0009] S3, placing the battery cell in the expanded state at one end of the end plate along a preset direction and abutting against the end plate, wherein the expansion direction of the battery cell is parallel to the preset direction;

[0010] S4, fixing the strap on the base frame and bundling the strap on the end surface of the end plate away from the battery cell along the preset direction;

[0011] S5, driving the battery cell to move a preset distance along a preset direction toward the end plate;

[0012] S6. Substituting the preset distance as the expansion amount into the coordinate curve to obtain the value of the reaction force;

[0013] S7. Record the deformation of the end plate along the preset direction, and observe whether cracks occur on the end plate.

[0014] As an optional solution, the S1 includes:

[0015] S111. Provide a first clamping plate and a second clamping plate disposed opposite to each other, and clamp the battery cell in the normal state between the first clamping plate and the second clamping plate, wherein the first clamping plate is fixed and the second clamping plate is movable along the direction in which the first clamping plate and the second clamping plate are disposed opposite to each other, and wherein the battery cell expands in a direction parallel to the direction in which the first clamping plate and the second clamping plate are disposed opposite to each other;

[0016] S112: The first clamping plate and the second clamping plate jointly apply a pre-tightening force of a first preset value to the battery cell to lock and fix the battery cell;

[0017] S113, performing a charge-discharge cycle on the battery cell, and monitoring the force applied to the second clamping plate in real time;

[0018] S114, when it is monitored that the force exerted on the second movable clamping plate reaches a second preset value, driving the second clamping plate to move in a direction away from the first clamping plate until the force exerted on the second clamping plate is zero, and recording the movement distance of the second clamping plate;

[0019] S115 , drawing the coordinate curve according to the force applied to the second clamping plate and the movement distance of the second clamping plate.

[0020] As an optional solution, the S1 includes:

[0021] S121. Provide a third clamping plate and a fourth clamping plate disposed opposite to each other, clamp the battery cell in the expanded state between the third clamping plate and the fourth clamping plate, wherein the third clamping plate is fixed and the fourth clamping plate is movable along the direction in which the third clamping plate and the fourth clamping plate are disposed opposite to each other, and the expansion direction of the battery cell is parallel to the direction in which the third clamping plate and the fourth clamping plate are disposed opposite to each other;

[0022] S122, driving the fourth clamping plate to move toward the third clamping plate, so that the battery cell in the expanded state switches to the normal state, and recording the driving force applied to the fourth clamping plate and the movement distance of the fourth clamping plate;

[0023] S123 , drawing the coordinate curve according to the driving force applied to the fourth clamping plate and the moving distance of the fourth clamping plate.

[0024] End plate strength testing device. The end plate strength testing method described above can be applied to the end plate strength testing device. The end plate strength testing device includes:

[0025] The base frame can be detachably fixed to one end of the end plate perpendicular to the preset direction;

[0026] The battery cell in the expanded state can abut against one end surface of the end plate along the preset direction in a state where the expansion direction of the battery cell is parallel to the preset direction;

[0027] The strap is detachably fixed to the base frame, and the strap can abut against the end surface of the end plate away from the battery cell along the preset direction;

[0028] a driving mechanism configured to drive the battery cell to move along the preset direction toward the end plate; and

[0029] The displacement detection member is used to detect the displacement of the end plate along the preset direction.

[0030] As an optional solution, a guide channel is provided in the base frame, the guide channel extends along the preset direction, the end plate is fixed at one end of the guide channel, and the battery cell is accommodated in the guide channel.

[0031] As an optional solution, the end plate strength testing device further includes:

[0032] The adapter is provided at one end of the battery core away from the end plate along the preset direction, the adapter abuts against the battery core, and is configured to dock with the output end of the driving mechanism.

[0033] As an optional solution, the end plate strength testing device further includes:

[0034] A shooting component is used to shoot the end plate.

[0035] As an optional solution, the end plate strength testing device includes a plurality of the battery cells in the expanded state, and the plurality of the battery cells in the expanded state are stacked in sequence along the preset direction, and the expansion direction of each of the battery cells is parallel to the preset direction.

[0036] As an optional solution, the end plate strength testing device further includes at least two of the straps, which are arranged at intervals, and both of the straps abut against the end surface of the end plate away from the battery cell along the preset direction.

[0037] As an optional solution, the end plate strength testing device further includes:

[0038] Bolt, the base frame is provided with a fixing beam, the fixing beam is provided with a fixing hole, the end of the end plate perpendicular to the preset direction has a through hole, and the threaded end of the bolt passes through the through hole and is threadedly fixed to the fixing hole.

[0039] Beneficial effects of the present invention:

[0040] The end plate strength testing method provided by the present invention can provide accurate and real data support for subsequent end plate strength testing by first drawing a coordinate curve of the expansion amount of the battery cell and the reaction force required to maintain the battery cell in a normal state under the expansion amount according to the characteristics of the battery cell itself, and fixing the end plate on the base frame, setting the battery cell in an expanded state at one end of the end plate along a preset direction and abutting against the end plate to ensure that the expansion direction of the battery cell is parallel to the preset direction, and then fixing the strap on the base frame and bundling it outside the end face of the end plate away from the battery cell in the preset direction, so that the strap can provide a stopping force to the end plate along the preset direction toward the battery cell, and utilizing the abutment of the expansion arc surface of the battery cell in an expanded state with one end face of the end plate and the strap. The belt abuts against the other end face of the end plate, which truly simulates the positional relationship between the battery cell, end plate and belt in the battery module, and provides a real test environment for the subsequent strength test of the end plate. By driving the battery cell to move a preset distance along a preset direction toward the end plate, and substituting the preset distance into the coordinate curve to obtain the value of the reaction force, the reaction force is the pressure on the end plate at this time. By recording the deformation of the end plate along the preset direction at this time and observing whether cracks are generated in the end plate, the pressure on the end plate can be matched one by one with the deformation generated when the end plate is subjected to the pressure and the information on whether cracks are generated in the end plate. The strength test effect of the end plate is good, and real data support is provided for the design verification of the subsequent battery module.

[0041] The present invention also provides an end plate strength testing device. By applying the above-mentioned end plate strength testing method, it can truly simulate the positional relationship between the battery cells, end plates and straps in the battery module, provide a real testing environment for the strength test of the end plate, and have a good effect on the strength test of the end plate, providing real data support for the subsequent design verification of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of an end plate strength testing method provided by an embodiment of the present invention;

[0043] Figure 2 1 is a schematic diagram of the first structure of the end plate strength testing device and the end plate provided in an embodiment of the present invention;

[0044] Figure 3 1 is a second structural schematic diagram of the end plate strength testing device and the end plate provided in an embodiment of the present invention;

[0045] Figure 4 is a cross-sectional schematic diagram of an end plate strength testing device and an end plate provided in an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the structure of the bolts, fixed beams and end plates provided in an embodiment of the present invention;

[0047] Figure 6 It is a cross-sectional schematic diagram of the bolts, fixing beams and end plates provided in an embodiment of the present invention.

[0048] In the picture:

[0049] 100, battery cell; 200, strap; 300, base frame; 310, fixing beam; 311, fixing hole; 320, guide channel; 400, adapter; 500, displacement detection component; 600, bolt;

[0050] 2000, end plate; 2100, through hole. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0052] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0053] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0054] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0055] Example 1

[0056] During the assembly process of the battery module, multiple battery cells need to be stacked in sequence, with buffering and insulating spacers added between the battery cells, and an end plate added to each end of the multiple battery cells along the stacking direction. The battery module length is shrunk to a certain length by pre-pressing the battery cells in the stacking direction, and then a tie is applied around the battery cells and the end plates. The pre-pressing force is then released so that the tie wraps around the end plates, thereby securing the battery cells and the end plates. The grouped battery modules are then placed in a battery case, which has a fixed beam and bolts. The bolt holes of the end plates are coaxially arranged with the threaded holes of the fixed beams, and the bolts secure the battery modules to the fixed beams of the battery case. During the charging and discharging process, the battery cells will undergo volume changes due to the expansion force of the battery cells. The tie wraps and end plates constrain the volume expansion of the battery cells, thereby protecting the battery cell casing from excessive deformation and rupture, and protecting the safety of the battery module. When the cell expansion force exceeds the end plate's load-bearing capacity and the end plate fails, the cell will continue to expand unrestrained, ultimately leading to module failure and potentially irreversible damage such as internal short circuits and thermal runaway. With the continuous advancement of cell technology, cell energy density is increasing, generating greater cell expansion forces. Therefore, accurately and effectively evaluating the end plate's ability to withstand this expansion force has become a pressing issue.

[0057] For this reason, Figures 1 to 6 As shown, this embodiment provides an end plate strength testing method. This end plate strength testing method is used to test the strength of the end plate 2000. The end plate 2000 being tested is used to clamp and fix the battery cell 100. The battery cell 100 has a normal state consistent with the production specifications and an expanded state after expansion. The end plate 2000 can provide a reaction force to the battery cell 100 in the expanded state to maintain the normal state of the battery cell 100. Specifically, the end plate strength testing method includes the following steps:

[0058] S1. Draw a coordinate curve of the expansion amount of the battery cell 100 when it expands and the reaction force required to maintain the battery cell 100 in a normal state under the expansion amount;

[0059] S2, fixing the end plate 2000 on the base frame 300;

[0060] S3. Place the expanded battery cell 100 at one end of the end plate 2000 along a preset direction and abut against the end plate 2000, with the expansion direction of the battery cell 100 being parallel to the preset direction;

[0061] S4, fixing the strap 200 on the base frame 300 and simultaneously tying it to the end surface of the end plate 2000 away from the battery cell 100 in a preset direction;

[0062] S5, driving the battery cell 100 to move a preset distance along a preset direction toward the end plate 2000;

[0063] S6. Substitute the preset distance as the expansion amount into the coordinate curve to obtain the value of the reaction force;

[0064] S7. Record the deformation of the end plate 2000 along a preset direction, and observe whether cracks occur in the end plate 2000.

[0065] The end plate strength testing method first draws a coordinate curve of the expansion amount of the battery cell 100 and the reaction force required to maintain the battery cell 100 in a normal state under the expansion amount according to the characteristics of the battery cell 100 itself, which can provide accurate and real data support for the subsequent strength testing of the end plate 2000. By fixing the end plate 2000 on the base frame 300, the battery cell 100 in the expanded state is set at one end of the end plate 2000 along a preset direction and abutted against the end plate 2000, ensuring that the expansion direction of the battery cell 100 is parallel to the preset direction, and then fixing the strap 200 on the base frame 300 and bundling it outside the end face of the end plate 2000 away from the battery cell 100 in the preset direction, the strap 200 can provide a stopping force to the end plate 2000 along the preset direction toward the battery cell 100, and utilizing the expansion arc surface of the battery cell 100 in the expanded state to abut against one end face of the end plate 2000 and The strap 200 abuts against the other end face of the end plate 2000, realistically simulating the positional relationship between the battery cell 100, the end plate 2000 and the strap 200 in the battery module, providing a real test environment for the subsequent strength test of the end plate 2000, by driving the battery cell 100 to move a preset distance in a preset direction toward the end plate 2000, and substituting the preset distance into the coordinate curve to obtain the value of the reaction force, which is the pressure exerted on the end plate 2000 at this time. By recording the deformation of the end plate 2000 along the preset direction at this time and observing whether cracks are generated in the end plate 2000, the pressure exerted on the end plate 2000, the deformation generated when the end plate 2000 is subjected to the pressure, and the information on whether cracks are generated in the end plate 2000 can be matched one by one, which has a good effect on the strength test of the end plate 2000, and provides real data support for the design verification of the subsequent battery module.

[0066] It should be noted that in this embodiment, the preset direction is the up-down direction. In other embodiments, the specific orientation of the preset direction can be adaptively adjusted according to actual needs, and this embodiment does not impose any specific restrictions. Furthermore, the preset distance can also be adaptively adjusted while ensuring the normal operation of the battery cell 100, and this embodiment does not impose any specific restrictions.

[0067] It should be noted that the expansion amount of the battery cell 100 and the reaction force required to maintain the battery cell 100 in a normal state under this expansion amount are core confidential information of the manufacturer of the battery cell 100, and the relevant information is generally not disclosed to customers who purchase the battery cell 100. In order to obtain the expansion amount of the battery cell 100 and the reaction force required to maintain the battery cell 100 in a normal state under this expansion amount, and to complete the drawing of the coordinate curve, S1 includes:

[0068] S111. Provide a first clamping plate and a second clamping plate that are oppositely disposed. Clamp the battery cell 100 in a normal state between the first clamping plate and the second clamping plate. The first clamping plate is fixed and the second clamping plate is movable along the relative direction of the first clamping plate and the second clamping plate. The expansion direction of the battery cell 100 is parallel to the relative direction of the first clamping plate and the second clamping plate.

[0069] S112: The first clamping plate and the second clamping plate jointly apply a pre-tightening force of a first preset value to the battery cell 100 to lock and fix the battery cell 100;

[0070] S113, performing a charge-discharge cycle on the battery cell 100, and monitoring the force applied to the second clamping plate in real time;

[0071] S114, when it is monitored that the force exerted on the movable second clamping plate reaches a second preset value, driving the second clamping plate to move in a direction away from the first clamping plate until the force exerted on the second clamping plate is zero, and recording the movement distance of the second clamping plate;

[0072] S115 , drawing a coordinate curve according to the force applied to the second clamping plate and the movement distance of the second clamping plate.

[0073] By first using the first clamp and the second clamp to pre-fix the battery cell 100 along the expansion direction with a force of a first preset value, and then subjecting the battery cell 100 to a charge and discharge cycle, the battery cell 100 is squeezed against the first clamp and the second clamp by utilizing its own structural characteristics, and combined with real-time detection of the force applied to the second clamp, when it is detected that the force applied to the second clamp reaches a second preset value, the second clamp is driven to move away from the first clamp to provide space for the expansion of the battery cell 100, until the force applied to the second clamp is zero, at which point the battery cell 100 is fully expanded, and the expansion amount of the battery cell 100 can be obtained by recording the movement distance of the second clamp, and then a coordinate curve is drawn according to the movement distance of the second clamp and the force applied to it during the movement process.

[0074] This embodiment also provides an end plate strength testing device. The end plate strength testing device can apply the above-mentioned end plate strength testing method to realize the strength test of the end plate 2000. Specifically, the end plate strength testing device includes a base frame 300, a battery cell 100 in an expanded state, a strap 200, a driving mechanism and a displacement detection member 500, wherein the base frame 300 can be detachably fixed to one end of the end plate 2000 perpendicular to a preset direction, the battery cell 100 in an expanded state can abut against one end face of the end plate 2000 along a preset direction in a state where the expansion direction is parallel to the preset direction, the strap 200 is detachably fixed to the base frame 300, the strap 200 can abut against the end face of the end plate 2000 away from the battery cell 100 along the preset direction, the driving mechanism is configured to drive the battery cell 100 to move along the preset direction toward the end plate 2000, and the displacement detection member 500 is used to detect the displacement of the end plate 2000 along the preset direction. By detachably connecting one end of the end plate 2000 perpendicular to the preset direction to the base frame 300, and respectively arranging the battery cell 100 and the strap 200 on the two end surfaces of the end plate 2000 along the preset direction, the driving mechanism drives the battery cell 100 to move along the preset direction toward the end plate 2000, and combined with the stop of the end plate 2000 by the strap 200, the effect of truly simulating the working state of the end plate 2000 is achieved, and the displacement detection component 500 is used to detect the deformation of the end plate 2000 along the preset direction, thereby improving the test accuracy.

[0075] It should be noted that, in this embodiment, the driving mechanism is a universal mechanical testing machine, and the displacement detection member 500 is a displacement sensor. The universal mechanical testing machine supports a variety of mechanical tests such as tension, compression, bending, shearing, peeling, bursting, fatigue, etc., and can simulate the stress conditions of the material in actual use. The displacement sensor has high detection accuracy. The mutual cooperation between the universal mechanical testing machine and the displacement sensor can achieve high-precision detection of the end plate 2000. In other embodiments, the driving mechanism can also be other compression drive structures, and the displacement detection member 500 can also be a grating electronic or purely mechanical vernier caliper to measure the deformation of the end plate 2000, which only needs to meet the specified accuracy requirements.

[0076] To further improve the precision with which the drive mechanism drives the battery cell 100 in a predetermined direction, a guide channel 320 is provided within the base frame 300. The guide channel 320 extends in the predetermined direction, and the end plate 2000 is secured to one end of the guide channel 320. The battery cell 100 is accommodated within the guide channel 320. When the drive mechanism drives the battery cell 100 in the predetermined direction, the battery cell 100 slides within the guide channel 320 in the predetermined direction, ensuring the precise movement of the battery cell 100.

[0077] In one alternative, the end plate strength testing device further includes an adapter 400, which is positioned at one end of the battery cell 100, away from the end plate 2000, in a predetermined direction. The adapter 400 abuts the battery cell 100 and is configured to interface with the output terminal of the drive mechanism. By providing the adapter 400 between the output terminal of the drive mechanism and the battery cell 100, direct contact between the drive mechanism and the battery cell 100 can be avoided, thereby improving protection for the battery cell 100.

[0078] Optionally, the end plate strength testing device includes a plurality of battery cells 100 in an expanded state, and the plurality of battery cells 100 in an expanded state are stacked in sequence along a preset direction, and the expansion direction of each battery cell 100 is parallel to the preset direction. By arranging a plurality of battery cells 100 in an expanded state along a preset direction, it is ensured that the expansion direction of each battery cell 100 is parallel to the preset direction, and the strength test of the end plate 2000 when assembling a plurality of battery cells 100 can be achieved to meet different test requirements. It should be noted that, if Figure 4 As shown, the end plate strength testing device includes 7 battery cells 100. In other embodiments, the number of battery cells 100 can also be adaptively adjusted according to actual needs, and this embodiment does not specifically limit it.

[0079] In addition, the end plate strength test device includes at least two straps 200, which are arranged at intervals and are in contact with the end surface of the end plate 2000 away from the battery cell 100 along a preset direction. By providing at least two straps 200 to jointly stop the end plate 2000, different test requirements can be further met. It should be noted that in this embodiment, if Figure 2 and Figure 3 As shown, the end plate strength testing device includes two straps 200. In other embodiments, the number of straps 200 can also be adaptively adjusted according to actual needs.

[0080] Combine Figure 5 and Figure 6 The connection structure between the end plate 2000 and the base frame 300 is described below. The end plate strength testing device also includes a bolt 600. The base frame 300 is provided with a fixing beam 310, which has a fixing hole 311. The end of the end plate 2000, perpendicular to the preset direction, has a through hole 2100. The threaded end of the bolt 600 passes through the through hole 2100 and is threadedly fixed to the fixing hole 311.

[0081] By using the bolt 600 to pass through the through hole 2100 in the end plate 2000 and then screw-fix it to the fixing hole 311 in the fixed beam 310 in the base frame 300, the end plate 2000 and the base frame 300 are detachably fixed, and the fixing effect is good.

[0082] In addition, in this embodiment, the strap 200 is also detachably fixed to the base frame 300 by bolts 600. To ensure brevity, no further details will be given here.

[0083] To further facilitate observation of cracks in the end plate 2000, the end plate strength testing device further includes a camera for photographing the end plate 2000. It should be noted that in this embodiment, the camera is a camera. By capturing images of the end plate 2000 with the camera, the end plate 2000 can be observed from a distance, improving observation convenience.

[0084] Example 2

[0085] This embodiment provides a method for testing the strength of an end plate. The method for testing the strength of an end plate provided in this embodiment is substantially the same as that in the first embodiment, but differs from the first embodiment in that different parameters are used when drawing the coordinate curve.

[0086] Specifically, S1 of this embodiment includes:

[0087] S121. Provide a third clamping plate and a fourth clamping plate disposed opposite to each other, and clamp the expanded battery cell 100 between the third clamping plate and the fourth clamping plate. The third clamping plate is fixed, and the fourth clamping plate is movable along the direction in which the third clamping plate and the fourth clamping plate are disposed opposite to each other. The expansion direction of the battery cell 100 is the direction in which the third clamping plate and the fourth clamping plate are disposed opposite to each other.

[0088] S122, driving the fourth clamping plate to move toward the third clamping plate, so that the battery cell 100 in the expanded state switches to the normal state, and recording the driving force applied to the fourth clamping plate and the movement distance of the fourth clamping plate;

[0089] S123 , drawing a coordinate curve according to the driving force applied to the fourth clamping plate and the moving distance of the fourth clamping plate.

[0090] By first preventing the battery cell 100 in an expanded state from being located between the third and fourth clamping plates, ensuring that the expansion direction of the battery cell 100 is parallel to the relative direction of the third and fourth clamping plates, and then driving the fourth clamping plate to move toward the third clamping plate to squeeze the battery cell 100 in an expanded state to a normal state, the driving force applied to the fourth clamping plate and the moving distance of the fourth clamping plate are recorded, and a coordinate curve is drawn based on the driving force applied by the fourth clamping plate and the moving distance of the fourth clamping plate.

[0091] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. An end plate strength test method, wherein an end plate (2000) is used to clamp and fix a battery cell (100), wherein the battery cell (100) has a normal state identical to production specifications and an expanded state after expansion, and wherein the end plate (2000) can provide a reaction force to the battery cell (100) in the expanded state so as to maintain the battery cell (100) in the normal state, characterized in that: The end plate strength testing method comprises the following steps: S1. plotting a coordinate curve of the expansion amount of the battery cell (100) when it expands and the reaction force required to maintain the battery cell (100) in a normal state under the expansion amount; S2, fixing the end plate (2000) on the base frame (300); S3, placing the battery cell (100) in the expanded state at one end of the end plate (2000) along a preset direction and abutting against the end plate (2000), with the expansion direction of the battery cell (100) being parallel to the preset direction; S4, fixing the strap (200) on the base frame (300) and simultaneously bundling the strap on the end plate (2000) along the preset direction away from the end surface of the battery cell (100); S5, driving the battery cell (100) to move a preset distance in a preset direction toward the end plate (2000); S6. Substituting the preset distance as the expansion amount into the coordinate curve to obtain the value of the reaction force; S7. Record the deformation of the end plate (2000) along the preset direction, and observe whether cracks occur in the end plate (2000).

2. The end plate strength testing method according to claim 1, characterized in that: Said S1 comprises: S111, providing a first clamping plate and a second clamping plate that are arranged opposite to each other, clamping the battery cell (100) in the normal state between the first clamping plate and the second clamping plate, wherein the first clamping plate is fixed and the second clamping plate is movable along the direction in which the first clamping plate and the second clamping plate are arranged opposite to each other, and the expansion direction of the battery cell (100) is parallel to the direction in which the first clamping plate and the second clamping plate are arranged opposite to each other; S112, the first clamping plate and the second clamping plate jointly apply a pre-tightening force of a first preset value to the battery core (100) to lock and fix the battery core (100); S113, performing a charge-discharge cycle on the battery cell (100), and monitoring the force applied to the second clamping plate in real time; S114, when it is monitored that the force exerted on the second movable clamping plate reaches a second preset value, driving the second clamping plate to move in a direction away from the first clamping plate until the force exerted on the second clamping plate is zero, and recording the movement distance of the second clamping plate; S115 , drawing the coordinate curve according to the force applied to the second clamping plate and the movement distance of the second clamping plate.

3. The end plate strength testing method according to claim 1, characterized in that: Said S1 comprises: S121. Providing a third clamping plate and a fourth clamping plate that are arranged opposite to each other, clamping the battery cell (100) in the expanded state between the third clamping plate and the fourth clamping plate, wherein the third clamping plate is fixed and the fourth clamping plate is movable along the direction in which the third clamping plate and the fourth clamping plate are arranged opposite to each other, and the expansion direction of the battery cell (100) is parallel to the direction in which the third clamping plate and the fourth clamping plate are arranged opposite to each other; S122, driving the fourth clamping plate to move toward the third clamping plate, so that the battery cell (100) in the expanded state switches to the normal state, and recording the driving force applied to the fourth clamping plate and the movement distance of the fourth clamping plate; S123 , drawing the coordinate curve according to the driving force applied to the fourth clamping plate and the moving distance of the fourth clamping plate.

4. End plate strength testing device, characterized in that, The end plate strength testing method according to any one of claims 1 to 3 can be applied to the end plate strength testing device, which includes: The base frame (300) can be detachably fixed to one end of the end plate (2000) perpendicular to the preset direction; The battery core (100) is in the expanded state, and the battery core (100) can abut against an end surface of the end plate (2000) along the preset direction in a state where the expansion direction is parallel to the preset direction; The strap (200) is detachably fixed to the base frame (300), and the strap (200) is capable of abutting against an end surface of the end plate (2000) away from the battery cell (100) along the preset direction; a driving mechanism configured to drive the battery core (100) to move along the preset direction toward the end plate (2000); and The displacement detection member (500) is used to detect the displacement of the end plate (2000) along the preset direction.

5. The end plate strength testing device according to claim 4, characterized in that: A guide channel (320) is provided in the base frame (300), the guide channel (320) extending along the preset direction, the end plate (2000) is fixed to one end of the guide channel (320), and the battery cell (100) is accommodated in the guide channel (320).

6. The end plate strength testing device according to claim 4, characterized in that: The end plate strength testing device further comprises: An adapter (400) is provided at one end of the battery core (100) away from the end plate (2000) along the preset direction, the adapter (400) abuts against the battery core (100), and the adapter (400) is configured to dock with the output end of the drive mechanism.

7. The end plate strength testing device according to claim 4, characterized in that: The end plate strength testing device further comprises: A photographing component, wherein the photographing component is used to photograph the end plate (2000).

8. The end plate strength testing device according to claim 4, characterized in that: The end plate strength testing device comprises a plurality of the battery cells (100) in the expanded state, wherein the plurality of the battery cells (100) in the expanded state are stacked in sequence along the preset direction, and the expansion direction of each battery cell (100) is parallel to the preset direction.

9. The end plate strength testing device according to claim 4, characterized in that: The end plate strength testing device further comprises at least two straps (200), the two straps (200) being arranged at intervals, and both of the two straps (200) abut against the end surface of the end plate (2000) away from the battery cell (100) along the preset direction.

10. The end plate strength testing device according to claim 4, characterized in that: The end plate strength testing device further comprises: The base frame (300) is provided with a fixing beam (310), the fixing beam (310) is provided with a fixing hole (311), and the end plate (2000) has a through hole (2100) at one end perpendicular to the preset direction, and the threaded end of the bolt (600) passes through the through hole (2100) and is threadedly fixed to the fixing hole (311).

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