Battery shell testing device and testing method thereof

Abstract

The invention discloses a battery shell testing device and a testing method thereof. The battery shell testing device comprises a fixed seat, a detection assembly, a clamping assembly and an inflation and deflation assembly, a detection position is arranged on the fixed seat; a detection piece of the detection assembly is arranged at the side part of the detection position, and the detection piece is provided with a detection surface and is used for detecting the expansion degree of the to-be-detected shell; clamping plates of the clamping assembly are arranged on the two sides of the detection position, and the clamping plates are used for clamping the to-be-detected shell and the detection piece so that the detection face can be attached to the large face of the to-be-detected shell; the inflation and deflation assembly comprises an air guide pipe and an inflation and deflation generating piece, the two ends of the air guide pipe are communicated with the inflation and deflation generating piece and the cavity of the shell to be detected respectively, and the inflation and deflation generating piece is used for inflating or deflating the cavity through the air guide pipe. According to the battery shell testing device, the cavity of the shell to be tested is subjected to inflation and deflation operation, the expansion state of the battery in the charging and discharging cycle process is simulated, the expansion degree of the shell is measured, and the performance of a weld joint under different stress conditions is evaluated.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and in particular to a battery shell testing device and a testing method thereof. Background Art

[0002] During the battery production process, the battery shell and cover are usually spliced ​​by welding technology, which is a key step to ensure the sealing and structural integrity of the battery. However, the traditional welding quality assessment method mainly relies on the inspection of design parameters such as the weld depth and weld width. Although this assessment method can preliminarily determine whether the welding technical parameters meet the standards, it cannot intuitively and accurately reflect the actual bearing capacity of the weld between the battery cover and the shell, especially the durability performance during the actual use of the battery.

[0003] Specifically, during the actual charge and discharge cycle of the battery, due to the deintercalation process of lithium ions on the internal pole pieces, the battery cell will expand to a certain extent, resulting in a slightly bulging state on the large surface of the battery. This physical change will exert additional pressure on the weld between the cover and the shell, which may affect the integrity of the weld in the long term. Currently, there is a lack of effective direct testing methods for evaluating the bearing capacity of the shell weld during long-term use of the battery, making it impossible to accurately determine whether the battery and its system structure meet the long-term stability and safety requirements of the product.

[0004] Therefore, there is an urgent need for a battery casing testing device and a testing method thereof to overcome the above-mentioned defects. Summary of the invention

[0005] In order to overcome at least one of the defects described in the above-mentioned prior art, one of the purposes of the present application is to provide a battery shell testing device, which can simulate the expansion state of the battery during the charge and discharge cycle, and evaluate the performance of the weld under different stress conditions by measuring the expansion degree of the large surface of the shell under different charge and discharge states.

[0006] The second purpose of the present application is to provide a battery shell testing method, which performs an inflation test on the shell to be tested at different constant pressures. The pressure holding stage and the deflation operation simulate various pressure environments that the battery may encounter in actual use, which helps to evaluate the recovery ability of the shell and the durability of the weld.

[0007] One of the technical solutions adopted by this application to solve the problem is:

[0008] A battery casing testing device, comprising:

[0009] A fixing seat, wherein a detection position is provided on the fixing seat;

[0010] A detection assembly, comprising a detection member, the detection member is arranged at a side of the detection position, the detection member has a detection surface on a side facing the detection position, and the detection surface is used to detect the expansion degree of the shell to be tested when the shell to be tested is installed on the detection position;

[0011] A clamping assembly, comprising a clamping plate, the clamping plates being arranged on both sides of the detection position, the clamping plates being used to clamp the shell to be detected and the detection member so that the detection surface fits the large surface of the shell to be detected;

[0012] An air inflation and deflation assembly comprises an air duct and an air inflation and deflation generating component, wherein one end of the air duct is connected to the air inflation and deflation generating component, and the other end of the air duct is used to communicate with the cavity of the shell to be tested, and the air inflation and deflation generating component is used to inflate or deflate the cavity via the air duct.

[0013] As a preferred technical solution of the present application, the clamping plate includes a first clamping plate, a second clamping plate and a third clamping plate arranged in sequence along a straight line direction, the first clamping plate and the second clamping plate are arranged opposite to each other and form a first clamping interval, and the second clamping plate and the third clamping plate are arranged opposite to each other and form a second clamping interval;

[0014] The first clamping interval is used to clamp the shell to be tested so that the two large surfaces of the shell to be tested are respectively fitted with the first clamping plate and the second clamping plate; the detection piece is installed in the second clamping interval, and the two side surfaces of the detection piece are respectively fitted with the second clamping plate and the third clamping plate, and the side surface of the detection piece facing the second clamping plate is formed as the detection surface; the second clamping plate is used to receive and transmit the expansion force of the large surface, and the detection surface is used to detect the expansion force.

[0015] As a preferred technical solution of the present application, the clamping assembly includes a fixing plate, which is arranged opposite to the third clamping plate, and the fixing plate is connected to the fixing seat; the four corners of the fixing plate are provided with connecting rods, and the four connecting rods are sequentially passed through the fixing plate, the third clamping plate, the second clamping plate and the first clamping plate; the two ends of the connecting rod are respectively fixedly connected to the first clamping plate and the fixing seat, and the second clamping plate and the third clamping plate are movably connected to the connecting rod, so that the width of the first clamping interval and the second clamping interval can be adjusted.

[0016] As a preferred technical solution of the present application, the clamping assembly includes a pressure plate and an adjusting screw, the adjusting screw is passed through the middle of the fixed plate, the pressure plate is arranged at the end of the adjusting screw, and the adjusting screw is used to drive the pressure plate to approach and fit the third clamping plate during rotation.

[0017] As a preferred technical solution of the present application, an interface material layer is provided on one side of the first clamping plate and the second clamping plate facing the first clamping interval, and the interface material layer is used to deform when the large surface of the shell to be tested expands, thereby providing expansion avoidance space for the large surface of the shell to be tested.

[0018] As a preferred technical solution of the present application, the fixing seat includes a base and a top plate, and the detection position is formed on the base; the base and the top plate are connected by a connecting screw, and the base and the top plate are used to press against the two end faces of the shell to be tested so that the shell to be tested is limitedly installed at the detection position.

[0019] As a preferred technical solution of the present application, a pressing plate is provided at the bottom of the top plate, and the pressing plate is arranged corresponding to the detection position; the pressing plate is used to press the end face of the shell to be tested under the drive of the top plate.

[0020] As a preferred technical solution of the present application, a measuring hole is provided on the top plate, and the measuring hole is arranged corresponding to the detection position; the length of the measuring hole is greater than the width of the detection position.

[0021] As a preferred technical solution of the present application, a detection platform is fixedly provided on the base, and a groove is provided on the upper surface of the detection platform, and the groove forms the detection position, and the groove is used to accommodate the bottom of the shell to be tested.

[0022] The second technical solution adopted by this application to solve the problem is:

[0023] A battery housing testing method is applied to the above-mentioned battery housing testing device, wherein the testing method comprises:

[0024] Step S1: welding the shells and cover plates of multiple groups of shells to be tested using the same welding method and welding parameters to form welds, and recording the penetration depth and penetration width of the welds after welding;

[0025] Step S2: Move the top plate away from the base, and at the same time move the clamping plate on the side of the detection position away from the detection position, then install the shell to be tested on the detection position, and again move the top plate close to the base, so that the top plate and the base work together to press the two end faces of the shell to be tested; then move the clamping plate close to the detection position, and under the action of the clamping plate, the detection surface of the detection member fits with the large surface of the shell to be tested;

[0026] Step S3: Under the same test temperature (normal temperature or other required test temperature), use a repetitively inflatable and deflated gas generating component to inflate the cavities of different groups of shells to be tested at different constant pressures. After the inflation is completed, extend the dimension measuring device into the measuring hole to measure the expansion amount of the large surface of the shell to be tested, and at the same time, detect the expansion force of the large surface of the shell to be tested by the detection component; record the expansion amount and expansion force of the large surface of the shell to be tested corresponding to different pressures; wherein the pressure value range is 0.1-0.45MPa;

[0027] Step S4: After the pressure is maintained for 2 minutes, the air is released for 30 seconds;

[0028] Step S5: Repeat steps S3 and S4 to simulate the inflation and deflation cycles 5000 times;

[0029] Step S6: The penetration depth and the weld width of the weld are recorded again, and compared with the parameters recorded in step S1 to confirm the degree of damage to the weld under different pressures.

[0030] In summary, the battery case testing device and testing method provided by the present application have the following technical effects:

[0031] 1) The battery shell testing device of the present application can simulate the expansion state of the battery during the charge and discharge cycle, and at the same time detect the expansion degree of the large surface of the shell under different charge and discharge conditions, providing data basis for evaluating the performance of the weld under different stress conditions.

[0032] 2) The battery shell testing device of the present application simulates the stress conditions of the battery during actual use, and can more realistically restore the stress environment and dynamic stress changes of the battery during actual use; the experimental data measured by the detection component can more accurately reflect the stress conditions of the shell to be tested and its welds in actual use.

[0033] 3) The battery shell testing method of the present application performs an inflation test on the shell to be tested at different constant pressures. The pressure holding stage and the deflation operation simulate various pressure environments that the battery may encounter in actual use, which is helpful to evaluate the recovery ability of the shell and the durability of the weld; at the same time, by measuring the expansion amount and expansion force of the large surface of the shell to be tested, it provides important data on the expansion performance of the shell and the degree of damage to the weld. By comparing the changes in weld parameters before and after the test (such as penetration depth, weld width, etc.), the degree of damage to the weld under different pressures can be intuitively evaluated, which provides a strong basis for the improvement and optimization of weld quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of a battery casing testing device according to an embodiment of the present application;

[0035] Figure 2 This is a schematic diagram of the structure of a fixing base according to an embodiment of the present application;

[0036] Figure 3 This is a schematic diagram of the structure of the battery housing test device of the embodiment of the present application after the top plate is hidden;

[0037] Figure 4 A top view of a battery casing testing device according to an embodiment of the present application;

[0038] Figure 5 for Figure 4 Sectional view at AA in the middle;

[0039] Figure 6 This is a schematic diagram of the structure of the housing to be tested according to an embodiment of the present application;

[0040] Figure 7 This is a schematic diagram of the structure of the detection component of an embodiment of the present application.

[0041] The meanings of the reference numerals are as follows:

[0042] 1. Fixing seat; 10. Detection position; 11. Base; 12. Top plate; 13. Connecting screw; 14. Measuring hole; 15. Detection table; 16. Mounting slot; 2. Shell to be tested; 21. Main shell; 22. Cover plate; 23. Large surface; 24. End surface; 25. Cavity; 26. Connecting port; 27. Pressing plate; 3. Detection piece; 4. Clamping assembly; 41. First clamping plate; 42. Second clamping plate; 43. Third clamping plate; 44. Fixing plate; 45. Connecting rod; 46. Adjusting screw; 47. Pressing plate; 48. Interface material layer. DETAILED DESCRIPTION

[0043] For better understanding and implementation, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0044] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0046] Embodiment 1

[0047] See also Figures 1 to 5 The present application discloses a battery housing testing device, which includes a fixing seat 1, a detection component, a clamping component 4 and a charging and discharging component. Figure 2 , a detection position 10 is provided on the fixing seat 1; see Figure 3 as well as Figure 7 The detection component includes a detection member 3, which is arranged on the side of the detection position 10, and the detection member 3 has a detection surface on the side facing the detection position 10, and the detection surface is used to detect the expansion degree of the shell 2 to be tested when the shell 2 to be tested is installed on the detection position 10.

[0048] See again Figure 1 and Figure 3 The clamping assembly 4 specifically includes a clamping plate, which is arranged on both sides of the detection position 10, wherein the clamping plate is used to clamp the shell 2 to be tested and the detection member 3, so that the detection surface fits the large surface 23 of the shell 2 to be tested. In addition, the inflation and deflation assembly includes an air guide tube and an inflation and deflation generating member, one end of the air guide tube is connected to the inflation and deflation generating member, and the other end of the air guide tube is used to communicate with the cavity 25 of the shell 2 to be tested, and the inflation and deflation generating member is used to inflate or deflate the cavity 25 via the air guide tube.

[0049] On the basis of this structure, when using the battery shell test device of the present application, the shell 2 to be tested is first placed on the detection position 10 of the fixing seat 1 to limit the movement of the shell 2 to be tested. Then adjust the clamping assembly 4 so that the clamping plate clamps the shell 2 to be tested and the detection member 3 of the detection assembly to ensure that the detection surface is tightly fitted with the large surface 23 of the shell 2 to be tested. Then the other end of the air guide tube of the inflation and deflation assembly is connected to the cavity 25 of the shell 2 to be tested, and the inflation and deflation generating member deflates into the cavity 25 through the air guide tube.

[0050] It should be noted that the housing 2 to be tested includes a main housing 21 and a cover plate 22. Figure 6 The cover plate 22 is arranged at one end of the main shell 21 and is welded to the main shell 21 by a welding process to form the shell 2 to be tested. The weld where the cover plate 22 and the main shell 21 are connected is located at the end of the large surface 23 of the shell 2 to be tested, which makes the weld a weak point in the shell structure. When the middle of the large surface 23 of the shell 2 to be tested expands during the charge and discharge cycle, the weld is easily pulled by the expansion of the large surface 23 of the shell, and long-term stress may cause the weld to crack, thereby affecting the sealing and overall strength of the shell.

[0051] Therefore, the present application simulates the expansion state of the shell 2 to be tested during the charge-discharge cycle by charging and discharging the cavity 25, thereby performing fatigue resistance test on the weld position. Specifically, when performing the test, the gas charging and discharging generating element is first started, and the cavity 25 of the shell 2 to be tested is continuously inflated through the air duct. During the inflation process, the pressure condition of the detection surface on the detection element 3 is observed and recorded to evaluate the expansion degree of the shell 2 to be tested, thereby evaluating the performance of the weld under different stress conditions.

[0052] In addition, according to specific test requirements, multiple cycles of inflation and deflation are required. Such cyclic tests can more comprehensively simulate the dynamic stress changes that the battery may encounter during long-term use, thereby further evaluating the fatigue resistance of the weld.

[0053] In addition, it should be noted that the battery shell test device of the present application simulates the stress conditions of the battery during actual use, specifically: the fixing seat 1 acts as a support frame in the battery pack or battery module, and when the shell 2 to be tested is placed on the fixing seat 1, its stress state is similar to the stress state in the real battery pack or battery module. The clamping assembly 4 acts as the two side end plates of the shell 2 to be tested, simulating the stress state of the battery in actual use, and also enables the detection member 3 to accurately capture the deformation of the shell 2 to be tested during inflation or deflation.

[0054] Therefore, the battery shell testing device of the present application can more realistically restore the stress environment and dynamic stress changes of the battery during actual use, and the experimental data measured by the detection component 3 can more accurately reflect the stress conditions of the shell 2 to be tested and its welds in actual use.

[0055] As a preferred technical solution of this application, refer to Figure 3 as well as Figure 5 The clamping plates include a first clamping plate 41, a second clamping plate 42 and a third clamping plate 43 which are arranged in sequence along a straight line, wherein the first clamping plate 41 and the second clamping plate 42 are arranged opposite to each other and form a first clamping interval, and the second clamping plate 42 and the third clamping plate 43 are arranged opposite to each other and form a second clamping interval.

[0056] Specifically, the first clamping interval is used to clamp the shell 2 to be tested, so that the large surfaces 23 on both sides of the shell 2 to be tested are respectively fitted with the first clamping plate 41 and the second clamping plate 42. In addition, the detection member 3 is installed in the second clamping interval, and the two side surfaces of the detection member 3 are respectively fitted with the second clamping plate 42 and the third clamping plate 43, and the side surface of the detection member 3 facing the second clamping plate 42 is formed as the detection surface. Among them, the second clamping plate 42 is used to receive and transmit the expansion force of the large surface 23, and the detection surface is used to detect the expansion force.

[0057] On the basis of this structure, when the shell 2 to be tested is simulated, the shell 2 to be tested is first placed between the first clamping plate 41 and the second clamping plate 42 to ensure that the large surfaces 23 on both sides of the shell 2 to be tested are respectively tightly fitted with the first clamping plate 41 and the second clamping plate 42. Next, the detection member 3 is installed between the second clamping plate 42 and the third clamping plate 43; and the surfaces on both sides of the detection member 3 are respectively fitted with the second clamping plate 42 and the third clamping plate 43.

[0058] Then, the shell 2 to be tested is inflated through the inflation and discharge assembly. Depending on the amount of inflation, the large surface 23 of the shell expands to different degrees after inflation. In this process, since the two sides of the second clamping plate 42 are respectively in contact with the large surface 23 of the shell and the detection surface, the second clamping plate 42 can be used as a force transmission medium, receiving the expansion force from the shell on the one hand, and transmitting it to the detection member 3 on the other hand. When the expansion force acts on the detection surface, the detection member 3 will present the corresponding detection result. Finally, by manually or systematically analyzing these detection data, the expansion of the large surface 23 of the shell 2 to be tested under different charge and discharge cycles can be evaluated, and then its impact on the weld can be evaluated.

[0059] It should be noted that the housing 2 to be tested is supported by the fixing seat 1, so when the housing 2 to be tested and the clamping plate are fitted, there is no force acting on the clamping plate. The fitting effect here is that when the housing 2 to be tested is inflated, the force of the expansion of the housing 2 to be tested can be quickly transmitted to the clamping plates on both sides.

[0060] The clamping interval formed by the first clamping plate 41, the second clamping plate 42 and the third clamping plate 43 ensures the stability of the tested housing 2 and the detection member 3 during the test, and reduces the test error caused by shaking or instability by a close fit. The second clamping plate 42, as a force transmission medium, can transmit the expansion force from the housing to the detection member 3, ensuring the accuracy and reliability of the test results.

[0061] In addition, the detection component 3 of the present application is a pressure sensor, a strain type pressure sensor, etc. By fitting the detection surface of the pressure sensor with the large surface 23 of the shell 2 to be tested, the detection surface can directly measure the overall expansion force or local expansion force of the large surface 23 of the shell, and convert it into an electrical signal to transmit to the system.

[0062] The inflation and deflation generating part may be an air pump, an airtight device, etc. A connection port 26 is provided on the cover plate 22, and the air guide pipe extends into the cavity 25 through the connection port 26, and the air guide pipe and the connection port 26 are sealed and fixed by structural adhesive.

[0063] As a preferred technical solution of the present application, the clamping assembly 4 also includes a fixing plate 44, which is arranged opposite to the third clamping plate 43, and the fixing plate 44 is connected to the fixing seat 1. Among them, a connecting rod 45 is provided at each of the four corners of the fixing plate 44. Specifically, the four connecting rods 45 are sequentially penetrated through the fixing plate 44, the third clamping plate 43, the second clamping plate 42 and the first clamping plate 41, and the two ends of the connecting rod 45 are fixedly connected to the first clamping plate 41 and the fixing seat 1 respectively. At the same time, the second clamping plate 42 and the third clamping plate 43 are movably connected to the connecting rod 45, so that the width of the first clamping interval and the second clamping interval can be adjusted.

[0064] On this structural basis, the fixing plate 44 is first fixedly connected to the fixing seat 1 by an appropriate method (such as bolt connection, welding, etc.). The fixing plate 44 serves as the reference surface of the entire clamping assembly 4, ensuring the stability and accuracy of the entire device. Next, four connecting rods 45 are respectively inserted into the four corners of the fixing plate 44, and pass through the third clamping plate 43, the second clamping plate 42 and the first clamping plate 41 in sequence. The two ends of the connecting rod 45 are respectively fixedly connected to the first clamping plate 41 and the fixing seat 1, forming a stable support structure.

[0065] In this process, the second clamping plate 42 and the third clamping plate 43 are connected to the connecting rod 45 in a movable manner (such as a sliding connection, a threaded connection, etc.) to allow them to move along the connecting rod 45 within a certain range, thereby adjusting the widths of the first clamping interval and the second clamping interval. Therefore, according to the size of the housing 2 to be tested, by adjusting the positions of the second clamping plate 42 and the third clamping plate 43 on the connecting rod 45, the appropriate widths of the first clamping interval and the second clamping interval can be set.

[0066] After the adjustment is completed, the shell 2 to be tested is placed in the first clamping interval, and the detection piece 3 is installed in the second clamping interval, and then the second clamping plate 42 and the third clamping plate 43 are fine-tuned so that both sides of the shell 2 to be tested and the detection piece 3 are in contact with the clamping plates. At this time, the second clamping plate 42 and the third clamping plate 43 are fixedly connected to the connecting rod 45 to avoid loosening or displacement during the test.

[0067] When the shell 2 to be tested expands after being inflated, the expansion force of the shell 2 to be tested is transmitted to the detection surface in contact with the second clamping plate 42 through the second clamping plate 42 in contact with it, so that the detection component 3 can detect the local force or overall force of the large surface 23 of the shell.

[0068] Thus, by adjusting the width of the clamping interval, the clamping assembly 4 can adapt to different sizes of the shell 2 to be tested, thereby improving the flexibility and applicability of the test. The detection member 3 can accurately receive and record the expansion force data from the shell, providing a reliable basis for evaluating the performance of the shell.

[0069] In addition, see Figure 2 The fixing seat 1 is provided with a mounting groove 16, and the lower end of the fixing plate 44 is installed in the mounting groove 16, so that the fixing plate 44 is limitedly connected with the fixing seat 1. At this time, no fasteners are required for fixed installation, which is convenient for disassembly and assembly.

[0070] As a preferred technical solution of this application, refer to Figure 5 The clamping assembly 4 includes a pressure plate 47 and an adjusting screw 46. Specifically, the adjusting screw 46 is disposed in the middle of the fixing plate 44, and the pressure plate 47 is disposed at the end of the adjusting screw 46. The adjusting screw 46 is used to drive the pressure plate 47 to approach and fit the third clamping plate 43 during the rotation process.

[0071] Based on this structure, the second clamping plate 42 and the third clamping plate 43 can be slidably arranged on the connecting rod 45; after the second clamping plate 42 and the third clamping plate 43 are moved and the first clamping interval and the second clamping interval are adjusted, the adjusting screw 46 can be rotated to make the pressure plate 47 approach and fit the third clamping plate 43. In this way, after the shell 2 to be tested expands, since the movement of the third clamping plate 43 is restricted by the pressure plate 47, the width of the first clamping interval and the second clamping interval will not change, and the second clamping plate 42 can accurately transmit the expansion force of the shell 2 to be tested to the detection member 3.

[0072] Among them, the outer periphery of the adjusting screw 46 is provided with an external thread, and the middle part of the fixing plate 44 is provided with a threaded hole. The adjusting screw 46 is threadedly connected to the threaded hole so that when the adjusting screw 46 rotates, the rotational motion can be converted into the forward and backward motion of the adjusting screw 46, thereby driving the pressure plate 47 to approach or move away from the third clamping plate 43.

[0073] Thus, by adjusting the cooperation between the screw rod 46 and the pressure plate 47, the position of the third clamping plate 43 is ensured to be stable during the test. Even if the shell 2 to be tested expands, the widths of the first clamping interval and the second clamping interval will not change due to the limiting effect of the pressure plate 47. At the same time, the second clamping plate 42 can accurately transmit the expansion force of the shell 2 to the test piece 3, so that the test device can more accurately evaluate the performance of the weld under different stress conditions.

[0074] As a preferred technical solution of this application, refer to Figure 3 as well as Figure 5 The first clamping plate 41 and the second clamping plate 42 are both provided with an interface material layer 48 on one side facing the first clamping interval, wherein the interface material layer 48 is used to deform when the large surface 23 of the shell 2 to be tested expands, thereby providing expansion avoidance space for the large surface 23 of the shell 2 to be tested.

[0075] Specifically, when the housing 2 to be tested is placed on the detection position 10 of the fixing seat 1, the two sides of the interface material layer 48 are in close contact with the large surface 23 of the housing 2 to be tested and the clamping plate, respectively, to simulate the stress state of the battery in actual use. The interface material layer 48 is PC foam, plastic board, etc.

[0076] In the process of the inflation and deflation generating element inflating the cavity 25 of the shell 2 to be tested, the interface material layer 48 will deform as the shell 2 to be tested expands, thereby absorbing and dispersing the force generated by the expansion of the shell 2 to be tested, and the expansion force of the shell 2 to be tested will be more evenly transmitted to the second clamping plate 42 through the interface material layer 48, and then transmitted to the detection surface, so that the data measured by the detection surface is more accurate. At the same time, the deformation of the interface material layer 48 can provide the shell with the necessary expansion avoidance space, avoiding damage or rupture of the shell due to excessive expansion.

[0077] It should be noted that, since the interface material layer 48 absorbs part of the expansion force during the deformation process, the force detected by the detection surface is the remaining expansion force after absorption. Since the interface material layer 48 is also provided between the two sides of the battery and the end plate during actual use, the present application can more accurately reflect the force conditions of the battery in actual use by providing the interface material layer 48 on the detection device.

[0078] In addition, the strength and fatigue resistance of the weld can also be evaluated by observing the deformation of the interface material layer 48 and the force detected on the detection surface.

[0079] As a preferred technical solution of this application, refer to Figure 2 The fixing base 1 includes a base 11 and a top plate 12, and the detection position 10 is formed on the base 11. The base 11 and the top plate 12 are connected by a connecting screw 13, and the base 11 and the top plate 12 are respectively used to press against two end surfaces 24 of the shell 2 to be tested, so that the shell 2 to be tested is limitedly installed at the detection position 10.

[0080] On the basis of this structure, when installing the shell 2 to be tested, first place one end face 24 of the shell 2 to be tested on the detection position 10 of the base 11; the detection position 10 is used to install and support the shell 2 to be tested, ensuring that the shell can remain stable during the test. Then adjust the position of the top plate 12 so that it is opposite to the other end face 24 of the shell 2 to be tested. Then, by rotating the connecting screw 13, adjust the distance between the top plate 12 and the base 11 to adapt to the shells 2 to be tested of different sizes, and at the same time make the top plate 12 gradually approach the other end face 24 of the shell 2 to be tested.

[0081] When the top plate 12 is in full contact with the end surface 24 of the shell 2 to be tested and generates a certain top pressure, the top plate 12 and the base 11 work together to limit the shell 2 to be tested and install it on the detection position 10. At this time, the connecting screw 13 should be in a locked state to prevent the top plate 12 from moving during the test.

[0082] After the shell 2 to be tested is installed, other parts of the test device can be started to perform test operations such as clamping or inflation. During the test, the fixing seat 1 will maintain a stable supporting effect to ensure that the shell 2 to be tested will not move under the test conditions.

[0083] Thus, the fixing base 1 realizes the limited installation of the shell 2 to be tested through the cooperation of the base 11 and the top plate 12, which can ensure that the shell remains stable during the test and prevent the accuracy of the test results from being affected by movement. The top plate 12 is connected to the base 11 through the connecting screw 13, and generates a certain top pressure on the end face 24 of the shell 2 to be tested; this top pressure can simulate the stress state of the battery in actual use, which helps to more accurately evaluate the performance of the shell.

[0084] As a preferred technical solution of the present application, a pressing plate 27 is provided at the bottom of the top plate 12, and the pressing plate 27 is arranged corresponding to the detection position 10. The pressing plate 27 is used to press the end surface 24 of the housing 2 to be tested under the drive of the top plate 12.

[0085] Based on this structure, when the connecting screw 13 is gradually tightened to gradually move the top plate 12 toward the base 11 and lower it, the top plate 12 first drives the pressing plate 27 toward the end surface 24 of the shell 2 to be tested. When the pressing plate 27 contacts the end surface 24 of the shell 2 to be tested, the connecting screw 13 is further tightened to make the pressing plate 27 apply a certain pressure to the shell end surface 24.

[0086] The pressure plate 27 may be a plastic plate, which is disposed between the shell end surface 24 and the top plate 12 . When subjected to force, the pressure plate 27 may deform to absorb and diffuse the pressure of the top plate 12 and evenly transfer it to the cover plate 22 .

[0087] Thus, the pressing plate 27 applies a certain pressure to the shell end surface 24, which can fix the shell 2 to be tested and prevent it from moving during the test.

[0088] As a preferred technical solution of this application, refer to Figure 4 A measuring hole 14 is provided on the top plate 12, and the measuring hole 14 is arranged corresponding to the detection position 10. The length of the measuring hole 14 is greater than the width of the detection position 10.

[0089] On the basis of this structure, during the charge-discharge cycle test of the shell 2 to be tested, measuring tools such as a vernier caliper and a scale ruler can be selected. For example, the measuring end of the vernier caliper is inserted through the measuring hole 14 to make it contact with the large surfaces 23 on both sides of the shell 2 to be tested. The vernier caliper is gently pushed to ensure that its measuring end is in close contact with the shell surface, and the expansion amount of the shell during the test is recorded.

[0090] Thus, the measuring hole 14 allows the tester to directly measure the expansion of the shell during the test without removing the top plate 12 or performing other complicated operations, thereby improving the efficiency and accuracy of the test. In addition, the expansion of the large surface 23 of the shell 2 to be tested can be combined with the expansion force to jointly evaluate the stress condition of the weld.

[0091] As a preferred technical solution of this application, refer to Figure 2 A testing platform 15 is fixedly arranged on the base 11, and a groove is arranged on the upper surface of the testing platform 15, and the groove is formed as the testing position 10. The groove is used to accommodate the bottom of the housing 2 to be tested.

[0092] Specifically, the shape and size of the groove match the bottom of the shell 2 to be tested. When the shell 2 to be tested is installed in the groove, the groove only limits the two side surfaces of the shell 2 to be tested, and the large surfaces 23 on both sides of the shell 2 to be tested can expand or contract freely without being restricted by the groove.

[0093] Thus, the setting of the groove can ensure that the shell is correctly placed during the test; at the same time, the groove provides a stable supporting surface for the shell 2 to be tested, which helps to prevent the shell from shifting or tilting during the test, thereby affecting the accuracy of the test results.

[0094] Embodiment 2

[0095] This embodiment discloses a battery case testing method, and the testing method of this embodiment can be applied to the battery case testing device in the first embodiment, wherein the testing method specifically includes the following steps:

[0096] Step S1: The shells and cover plates 22 of multiple shells 2 to be tested are welded to form welds using the same welding method and welding parameters, and the penetration depth and weld width of the welds are recorded after welding. The uniform welding method and parameters ensure that the weld quality of all shells 2 to be tested is comparable; the recording of penetration depth and weld width provides benchmark data for the subsequent evaluation of the degree of damage to the welds.

[0097] Step S2: Move the top plate 12 away from the base 11, and at the same time move the clamping plate on the side of the detection position 10 away from the detection position 10, then install the shell 2 to be tested on the detection position 10, and move the top plate 12 close to the base 11 again, and the top plate 12 and the base 11 work together to press the two end faces 24 of the shell 2 to be tested; then move the clamping plate close to the detection position 10, and under the action of the clamping plate, the detection surface of the detection member 3 fits the large surface 23 of the shell 2 to be tested. Among them, the pressing effect of the top plate 12 and the base 11 ensures the stability of the shell 2 to be tested during the test process, and avoids the test error caused by the movement of the shell.

[0098] Step S3: multiple shells 2 to be tested are divided into multiple groups to be tested. Under the same test temperature, a repetitively inflatable and deflated gas generating component is used to inflate the cavities 25 of different groups of shells 2 to be tested at different constant pressures. After the inflation is completed, the dimension measuring instrument is inserted into the measuring hole 14 to measure the expansion amount of the large surface 23 of the shell 2 to be tested, and the expansion force of the large surface 23 of the shell 2 to be tested is detected by the detection component 3; the expansion amount and expansion force of the large surface 23 of the shell 2 to be tested corresponding to different pressures are recorded; wherein, considering the actual use conditions and safety requirements of the battery shell, the pressure value range is 0.1~0.45MPa.

[0099] Therefore, different constant pressures simulate the different pressure environments that the battery may encounter in actual use, which helps to comprehensively evaluate the pressure-bearing capacity and deformation of the shell; and the measurement of expansion amount and expansion force provides important data for evaluating the expansion performance of the shell and the degree of damage to the weld.

[0100] Step S4: After the inflation is completed, the pressure is maintained for 2 minutes and then the air is released for 30 seconds. Therefore, the pressure maintenance stage helps to observe the deformation of the shell under continuous pressure and evaluate the pressure-bearing stability of the weld. The deflation operation simulates the pressure release that the battery may encounter in actual use, which helps to evaluate the recovery ability of the shell and the durability of the weld.

[0101] Step S5: Repeat steps S3 and S4 to simulate the charge and discharge cycle 5000 times. Thus, 5000 charge and discharge cycles simulate the long-term pressure change process of the battery in actual use, which helps to evaluate the durability and reliability of the shell and weld under long-term pressure. Through multiple cycle tests, the fatigue strength of the shell and the degree of damage to the weld can be more accurately evaluated.

[0102] Step S6: Record the penetration depth and width of the weld again, and compare them with the parameters recorded in step S1 to confirm the degree of damage to the weld under different pressures. Thus, by comparing the changes in weld parameters before and after the test, the degree of damage to the weld under different pressures can be intuitively evaluated. The degree of damage to the weld is one of the important indicators for evaluating the overall performance of the battery shell, and is of great significance for ensuring the safety and reliability of the battery.

[0103] In summary, the battery shell testing method of the present application performs an inflation test on the shell 2 to be tested at different constant pressures. The pressure holding stage and the deflation operation simulate various pressure environments that the battery may encounter in actual use, which is helpful to evaluate the recovery ability of the shell and the durability of the weld. At the same time, by measuring the expansion amount and expansion force of the large surface 23 of the shell 2 to be tested, important data on the expansion performance of the shell and the degree of damage to the weld are provided. By comparing the changes in weld parameters before and after the test (such as penetration depth, weld width, etc.), the degree of damage to the weld under different pressures can be intuitively evaluated, which provides a strong basis for the improvement and optimization of weld quality.

[0104] Therefore, the data provided by this test method can be used to guide the optimal design and improvement of the battery casing to improve its pressure bearing capacity, deformation recovery ability and weld durability.

[0105] The technical means disclosed in the present application are not limited to the technical means disclosed in the above-mentioned implementation methods, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications are also regarded as the protection scope of this application.

Claims

1. A battery casing testing device, characterized in that: include, A fixing seat, wherein a detection position is provided on the fixing seat; A detection assembly, comprising a detection member, the detection member is arranged at a side of the detection position, the detection member has a detection surface on a side facing the detection position, and the detection surface is used to detect the expansion degree of the shell to be tested when the shell to be tested is installed on the detection position; A clamping assembly, comprising a clamping plate, the clamping plates being arranged on both sides of the detection position, the clamping plates being used to clamp the shell to be detected and the detection member so that the detection surface fits the large surface of the shell to be detected; An air inflation and deflation assembly comprises an air duct and an air inflation and deflation generating component, wherein one end of the air duct is connected to the air inflation and deflation generating component, and the other end of the air duct is used to communicate with the cavity of the shell to be tested, and the air inflation and deflation generating component is used to inflate or deflate the cavity via the air duct.

2. The battery casing testing device according to claim 1, characterized in that: The clamping plate comprises a first clamping plate, a second clamping plate and a third clamping plate which are sequentially arranged along a straight line direction, the first clamping plate and the second clamping plate are arranged opposite to each other and form a first clamping interval, and the second clamping plate and the third clamping plate are arranged opposite to each other and form a second clamping interval; The first clamping interval is used to clamp the shell to be tested so that the two large surfaces of the shell to be tested are respectively fitted with the first clamping plate and the second clamping plate; the detection piece is installed in the second clamping interval, and the two side surfaces of the detection piece are respectively fitted with the second clamping plate and the third clamping plate, and the side surface of the detection piece facing the second clamping plate is formed as the detection surface; the second clamping plate is used to receive and transmit the expansion force of the large surface, and the detection surface is used to detect the expansion force.

3. The battery casing testing device according to claim 2, characterized in that: The clamping assembly includes a fixing plate, which is arranged opposite to the third clamping plate, and the fixing plate is connected to the fixing seat; the four corners of the fixing plate are provided with connecting rods, and the four connecting rods are sequentially passed through the fixing plate, the third clamping plate, the second clamping plate and the first clamping plate; the two ends of the connecting rod are fixedly connected to the first clamping plate and the fixing seat respectively, and the second clamping plate and the third clamping plate are movably connected to the connecting rod, so that the width of the first clamping interval and the second clamping interval can be adjusted.

4. The battery casing testing device according to claim 3, characterized in that: The clamping assembly includes a pressure plate and an adjusting screw, wherein the adjusting screw passes through the middle of the fixed plate, and the pressure plate is arranged at the end of the adjusting screw. The adjusting screw is used to drive the pressure plate to approach and fit the third clamping plate during rotation.

5. The battery casing testing device according to claim 2, characterized in that: An interface material layer is provided on one side of the first clamping plate and the second clamping plate facing the first clamping interval, and the interface material layer is used to deform when the large surface of the shell to be tested expands, so as to provide expansion avoidance space for the large surface of the shell to be tested.

6. The battery casing testing device according to claim 1, characterized in that: The fixing seat includes a base and a top plate, and the detection position is formed on the base; the base and the top plate are connected by a connecting screw, and the base and the top plate are used to press against the two end faces of the shell to be tested so that the shell to be tested is limitedly installed at the detection position.

7. The battery casing testing device according to claim 6, characterized in that: A pressing plate is provided at the bottom of the top plate, and the pressing plate is arranged corresponding to the detection position; the pressing plate is used to press the end surface of the shell to be tested under the drive of the top plate.

8. The battery casing testing device according to claim 6, characterized in that: The top plate is provided with a measuring hole, and the measuring hole is arranged corresponding to the detection position; the length of the measuring hole is greater than the width of the detection position.

9. The battery casing testing device according to claim 6, characterized in that: A detection platform is fixedly arranged on the base, and a groove is arranged on the upper surface of the detection platform. The groove is formed as the detection position, and the groove is used to accommodate the bottom of the shell to be tested.

10. A battery casing testing method, characterized in that: The testing method is applied to the battery housing testing device according to any one of claims 1 to 9, wherein the testing method comprises: Step S1: welding the main shells and cover plates of multiple groups of shells to be tested in the same welding method and with the same welding parameters to form welds, and recording the penetration depth and width of the welds after welding; Step S2: Move the top plate away from the base, and at the same time move the clamping plate on the side of the detection position away from the detection position, then install the shell to be tested on the detection position, and again move the top plate close to the base, so that the top plate and the base work together to press the two end faces of the shell to be tested; then move the clamping plate close to the detection position, and under the action of the clamping plate, the detection surface of the detection member fits with the large surface of the shell to be tested; Step S3: Under the same test temperature (normal temperature or other required test temperature), use a repetitively inflatable and deflated gas generating component to inflate the cavities of different groups of shells to be tested at different constant pressures. After the inflation is completed, extend the dimension measuring device into the measuring hole to measure the expansion amount of the large surface of the shell to be tested, and at the same time, detect the expansion force of the large surface of the shell to be tested by the detection component; record the expansion amount and expansion force of the large surface of the shell to be tested corresponding to different pressures; wherein the pressure value range is 0.1-0.45MPa; Step S4: After the pressure is maintained for 2 minutes, the air is released for 30 seconds; Step S5: repeating steps S3 and S4 to simulate the inflation and deflation cycles for 5000 times; Step S6: The penetration depth and the weld width of the weld are recorded again, and compared with the parameters recorded in step S1 to confirm the degree of damage to the weld under different pressures.

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