End plate strength testing apparatus and method

Abstract

The application provides an end plate strength testing device and method, which comprises a base and a pressing plate; the base comprises a support, the top of the support is concave downward to form a support matching surface, and the support matching surface is used for placing a binding belt matching area at the bottom of an end plate; the pressing plate comprises a first surface of the pressing plate, the first surface of the pressing plate is used for abutting and matching with the upper surface of the end plate, and the center of the first surface of the pressing plate is correspondingly arranged with the center of the upper surface of the end plate. The application tests the strength of the end plate by adopting the base and the pressing plate, adopts the support matching surface matched with the binding belt matching area, and adopts the first surface of the pressing plate matched with the expansion force and the expansion amount of the secondary battery, so that the end plate is truly simulated to bear the expansion force deformation of the module, which is helpful to quickly complete the test of the strength of the end plate and improve the test efficiency and ensure the test accuracy.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing technology, and more specifically, to an endplate strength testing device and method. Background Technology

[0002] Currently, in the development of module endplates, to test the endplate strength—that is, its ability to withstand the expansion force of the secondary battery cells within the module—it is necessary to design and manufacture a module including this endplate. Then, charge-discharge cycle testing is conducted until the module reaches the end of its lifespan. This approach has several problems: 1. The testing is very time-consuming, approximately 1.5 years, which clearly conflicts with the short product development and deployment cycle, failing to meet product development requirements; 2. Insufficient verification of the endplate's ability to withstand the module's expansion force before product use poses a risk of short circuits due to endplate breakage after module assembly; 3. Designing and manufacturing a module including this endplate for testing consumes significant equipment resources and time, resulting in low testing efficiency and very high testing costs.

[0003] A Chinese patent with publication number CN212871567U discloses a battery module expansion force testing device. The device includes a support assembly, two equivalent end plates, a pre-compression mechanism, and a cover plate. The support assembly comprises a U-shaped receiving space formed by a base plate and parallel first and second side plates, in which the battery module is disposed. The two equivalent end plates are parallel to the first side plates and respectively disposed at both ends of the battery module. A first pressure sensor is disposed between each equivalent end plate and the battery module. The pre-compression mechanism is connected to the first side plate and is used to compress the equivalent end plates to press the battery module against the second side plate with adjustable pressure. The cover plate is detachably connected to the upper side of the support assembly and parallel to the base plate. A second pressure sensor is disposed between the cover plate and the battery module.

[0004] The inventors believe that existing expansion force testing devices are all designed for batteries and lack testing devices for the ability of battery end plates to withstand expansion forces. Existing testing technologies are time-consuming and inefficient. Therefore, there is a need to provide an end plate strength testing device to test the ability of battery end plates to withstand module expansion forces. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide an end plate strength testing device and method.

[0006] An end plate strength testing device according to the present invention includes a base and a pressure plate; the base includes a support member, the top of which is recessed to form a support member mating surface, the support member mating surface being used to place the binding strap mating area at the bottom of the end plate; the pressure plate includes a first pressure plate surface, the first pressure plate surface being used to abut against the upper surface of the end plate, and the center of the first pressure plate surface being correspondingly disposed with the center of the upper surface of the end plate; the pressure plate further includes a second pressure plate surface opposite to the first pressure plate surface, the second pressure plate surface being used to transfer the load applied by the testing equipment to the end plate.

[0007] Preferably, the first surface of the pressure plate includes a downwardly convex arc surface, and the degree of convexity of the arc surface gradually increases from the edge of the first surface of the pressure plate to the center.

[0008] Preferably, the maximum height of the protrusion on the first surface of the pressure plate is G, and the thickness of the secondary battery cell is H, where 0.35H≥G≥0.002H.

[0009] Preferably, the first surface of the pressure plate includes a single hump surface, and the single hump surface forms a hemispherical protrusion downward from the center position of the first surface of the pressure plate.

[0010] Preferably, the first surface of the pressure plate includes a multi-hump surface, wherein the multi-hump surface forms multiple hemispherical protrusions downward from the first surface of the pressure plate, and the multi-hump surface includes two or more humps.

[0011] Preferably, the mating surface of the support member includes an arc surface and a clearance groove, the shape of the arc surface matching the mating area of ​​the strap; the depth of the clearance groove is not more than 10 times the width of the mating surface of the support member, and not less than 0.1 times the width of the mating surface of the support member.

[0012] Preferably, the width of the strap mating area is 0.1-20 mm larger than the width of the support mating surface.

[0013] Preferably, the base further includes a mounting base with multiple mounting holes, and the support member can be installed at different positions on the mounting base through different mounting holes.

[0014] Preferably, the two support members are installed on the mounting base respectively, and two sets of strap mating areas are symmetrically arranged on the end plate, and the distance between the two support members is consistent with the distance between the two sets of strap mating areas.

[0015] According to the present invention, a method for testing the strength of an end plate, using the aforementioned end plate strength testing device and further employing a testing equipment capable of applying pressure, includes the following steps:

[0016] Step S1: Place the base of the end plate strength testing device on the platform of the testing equipment;

[0017] Step S2: Place the end plate on the support member and adjust the distance between the two support members so that the strap mating area mates with the mating surface of the support member;

[0018] Step S3: Place the pressure plate on the end plate;

[0019] Step S4: Place the pressure head of the testing device at the center of the second surface of the pressure plate, so that the centers of the pressure head, the pressure plate, and the end plate are on the same vertical line;

[0020] Step S5: Pressurize the pressure plate. The initial pressure is 0N, the pressure threshold is the maximum expansion force of the battery, and the pressurization speed ranges from 0.1 to 450 mm / min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention uses a base and a pressure plate to test the strength of the end plate. By using a support surface that matches the area where the straps are fitted, and by using a first surface of the pressure plate that matches the expansion force and amount of the secondary battery, the invention realistically simulates the deformation of the end plate under the expansion force of the module. This helps to quickly complete the end plate strength test, improves the efficiency of the test, and ensures the accuracy of the test.

[0023] 2. This invention provides a support mating surface on the support member, an arc surface with the same curvature as the strap mating area on the support member mating surface, and a relief groove on the support member mating surface to allow space for deformation in the middle of the end plate. This helps to realistically simulate the deformation of the end plate under the expansion force of the module, which helps to improve the efficiency of the test and ensure the accuracy of the test.

[0024] 3. The present invention can be detachably installed by means of mounting base and support, and the installation position of support can be adjusted and support adapted to end plate can be replaced, which helps to improve the versatility of the base, thereby helping to improve testing speed and efficiency. Attached Figure Description

[0025] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0026] Figure 1 This is a schematic diagram illustrating the overall structure of the end plate strength testing device of this invention.

[0027] Figure 2 This is a schematic diagram illustrating the structure of the base, which is the main feature of this invention.

[0028] Figure 3 This is a schematic diagram illustrating the structure of the end plate, which is the main feature of this invention.

[0029] Figure 4 This is a bottom view of the end plate, which is the main feature of this invention.

[0030] Figure 5 This is a front view of the pressure plate, which is the main feature of this invention.

[0031] Figure 6 This is a top view of the pressure plate, which is the main feature of this invention;

[0032] Figure 7 This is a front view of the main support component of the present invention;

[0033] Figure 8 This is a top view that mainly illustrates the support member of the present invention;

[0034] Figure 9 This is a schematic diagram illustrating the shape of the first surface of the pressure plate in Variation Example 1 of the present invention;

[0035] Figure 10 This is a schematic diagram illustrating the shape of the first surface of the pressure plate in Variation Example 2 of the present invention;

[0036] Figure 11 This is a schematic diagram illustrating the shape of the first surface of the pressure plate in Variation Example 3 of the present invention.

[0037] As shown in the figure:

[0038] Base 1, Mounting bracket 11, Support 12

[0039] Support component mating surface 121, curved surface 1211, clearance groove 1212

[0040] Pressure plate 2, pressure plate first surface 21, pressure plate second surface 22

[0041] End plate 3, strap mating area 31 Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0043] Example 1

[0044] like Figure 1-6As shown, an end plate strength testing device according to the present invention includes a base 1 and a pressure plate 2; the base 1 includes a support member 12, the top of the support member 12 is recessed downward to form a support member mating surface 121, the support member mating surface 121 is used to place the binding strap mating area 31 at the bottom of the end plate 3; the pressure plate 2 includes a pressure plate first surface 21, the pressure plate first surface 21 is used to abut against the upper surface of the end plate 3, and the center of the pressure plate first surface 21 is correspondingly set with the center of the upper surface of the end plate 3; the pressure plate 2 also includes a pressure plate second surface 22 opposite to the pressure plate first surface 21, the pressure plate second surface 22 is used to transfer the load applied by the testing equipment to the end plate 3, that is, to simulate the module expansion force applied by the secondary battery cell to the end plate 3.

[0045] Currently, in the development of module endplates, in order to test the endplate strength, that is, to test the endplate's performance in withstanding the expansion force of the secondary battery cells within the module, it is necessary to design and manufacture the module with this endplate. This application avoids stacking a real module for long-term cyclic verification, and can quickly complete the test verification of the endplate's ability to withstand the module's expansion force, while maintaining a consistency with the actual situation, greatly improving the efficiency of endplate strength testing and ensuring the accuracy of the test.

[0046] The first surface 21 of the pressure plate abuts against the upper surface of the end plate 3 to simulate the expansion force exerted on the end plate 3 by the secondary battery within the module. To enhance the rigidity of the pressure plate 2 and prevent deformation, the thickness of the base material of the pressure plate 2 ranges from 5 to 200 mm. The size of the first surface 21 of the pressure plate is not smaller than the size of the secondary battery surface; preferably, they are the same size, thus enabling the pressure plate 2 to more realistically simulate a single secondary battery cell.

[0047] Because the expansion force varies at different locations on the surface of the secondary battery, the expansion amount also varies. Therefore, the pressure plate 2 is designed with an unequal thickness, i.e., a variable cross-section structure, so that the first surface 21 of the pressure plate can more realistically simulate the surface of a single secondary battery cell. The expansion force and expansion amount of the secondary battery gradually decrease from the center of the surface towards the edges. The first surface 21 of the pressure plate includes a downwardly convex arc surface, and the degree of convexity of the arc surface gradually increases from the edge to the center of the first surface 21 of the pressure plate.

[0048] like Figure 5As shown, the maximum height of the protrusion on the first surface 21 of the pressure plate is G, and its relationship with the thickness H of the secondary battery cell is 0.35H ≥ G ≥ 0.002H. During multiple charge-discharge cycles, the secondary battery cells within the module expand and generate expansion force. The cell expansion is between 0.002 times and 0.35 times the cell thickness. Therefore, to more accurately simulate the cell expansion and expansion force using the pressure plate, the maximum height G of the protrusion on the first surface 21 of the pressure plate is related to the thickness H of the secondary battery cell as 0.35H ≥ G ≥ 0.002H. The first surface 21 of the pressure plate is a protruding arc shape (jklmn), with point l representing the maximum height of the first surface 21. The heights of both the jkl and nml arc segments increase from 0 to G, thus simulating the gradual decrease in expansion force and amount of the secondary battery from the center of the surface towards the edges. The shape of the second surface 22 of the pressure plate may include a horizontally set plane or an arc surface, etc. There is no limitation in this embodiment, as long as it can transfer the load applied by the test equipment to the end plate 3.

[0049] The material of the pressure plate 2 is a high-hardness material, such as carbon steel, stainless steel, hard plastic, stone, etc.

[0050] The base 1 includes a mounting base 11 and a support member 12. The support member 12 is mounted on the mounting base 11. Depending on the actual use, there can be two or more support members 12. The mounting base 11 and the support member 12 are connected as one piece by bolts and / or welding, or the mounting base 11 and the support member 12 are integrally formed, such as by integral machining or die casting. To increase the versatility of the base 1 and make it suitable for testing various end plates 3, preferably, the base 1 is designed as a detachable and movable structural component. The mounting base 11 includes multiple mounting holes, and the support member 12 can be installed in different positions on the mounting base 11 through different mounting holes. By connecting with bolts, installation, disassembly, and repositioning can be achieved, greatly improving the applicability of the base 1.

[0051] Two support members 12 are installed on the mounting base 11 respectively. Two sets of strap mating areas 31 are symmetrically arranged on the end plate 3. The distance between the two support members 12 is consistent with the distance between the two sets of strap mating areas 31.

[0052] like Figure 7 and 8 As shown, the strap mating area 31 is placed on the support mating surface 121. The support mating surface 121 includes an arc surface 1211 and a clearance groove 1212. The shape of the arc surface 1211 matches the strap mating area 31. Generally, the strap mating area 31 is arc-shaped, and correspondingly, the arc surface 1211 is also arc-shaped, fully simulating the limitation of the strap on the end plate 3, thereby ensuring the accuracy of the test.

[0053] The width of the strap mating area 31 is B, the distance between the two sets of strap mating areas 31 is A, the width of the strap is C, and the width of the support mating surface 121 is D. Preferably, C and D are equal, and the value of B is 0.1-20mm larger than the value of D, so as to achieve the function of strap limiting.

[0054] Generally, a set of strap mating areas 31 formed by a strap includes two arc surfaces. Correspondingly, the arc surface 1211 includes arc segments abc and fgh. The arc surface 1211 contacts the strap mating area 31 in the form of a large surface. The clearance groove 1212 is the cdef groove between the arc segments abc and fgh. The groove depth is E, and its relationship with the width of the strap is: 0.1C≤E≤10C. It is used to reserve space for the deformation of the middle part of the end plate 3 during testing, so as to more realistically simulate the deformation of the end plate 3 under the expansion force of the module.

[0055] In use, this application allows for adjustment of the distance between the two support members 12 to ensure consistency with the distance between the two sets of strap mating areas 31, realistically simulating the deformation of the end plate 3 under the expansion force of the module. Alternatively, the support members 12 can be directly replaced with an arc surface 1211 with an appropriate curvature and a relief groove 1212 with an appropriate depth. This application can accommodate end plates 3 of different heights and shapes, greatly improving the versatility of the base 1. This application can quickly complete the testing and verification of the end plate's resistance to module expansion force, and it is basically consistent with the actual situation, greatly improving the efficiency of end plate strength testing and ensuring the accuracy of the test.

[0056] Variation Example 1

[0057] like Figure 9 As shown, based on Embodiment 1, the first surface 21 of the pressure plate can be a downwardly convex arc surface or a horizontally set plane. In one possible implementation, the material of the pressure plate 2 can be a material with a lower hardness than that in Embodiment 1, which can simulate the deformation of the secondary battery casing in the module, thereby simulating the expansion of different positions on the large surface of the secondary battery, thus ensuring a more comprehensive simulation and improving the accuracy of the test. In other possible implementations, the pressure plate 2 can also be made of the same material as in Embodiment 1.

[0058] Variation Example 2

[0059] like Figure 10 As shown, based on Embodiment 1, the first surface 21 of the pressure plate can be a single-hump surface in addition to being a downwardly convex arc surface. The single-hump surface forms a hemispherical convexity downward from the center of the first surface 21 of the pressure plate, thereby simulating the expansion of different positions of the secondary battery, thus ensuring a more comprehensive simulation and improving the accuracy of the test.

[0060] Variation Example 3

[0061] like Figure 11 As shown, based on Embodiment 1, the first surface 21 of the pressure plate can be a multi-hump surface in addition to being a downwardly convex arc surface. The multi-hump surface includes two or more humps. This embodiment does not impose a specific limit on the number of humps. When the multi-hump surface includes two humps, it is a double-hump surface. The double-hump surface forms two hemispherical protrusions symmetrically downward from the first surface 21 of the pressure plate, thereby simulating the expansion of different positions of the secondary battery surface, thus ensuring a more comprehensive simulation and improving the accuracy of the test.

[0062] Furthermore, the first surface 21 of the pressure plate can also have three or more hump surfaces, forming three or more hemispherical protrusions downward from the first surface 21 of the pressure plate. This embodiment does not specifically limit the number of hump surfaces; the number of hump surfaces is consistent with the number of hemispherical protrusions formed downward from the first surface 21 of the pressure plate. Additionally, the heights of the hemispherical protrusions formed by the multiple hump surfaces can be the same or different. In one possible implementation, the hump surface can include a first hump surface located at the center of the first surface 21 of the pressure plate, and multiple second hump surfaces arranged around the first hump surface with a set distance as the radius, forming a circle, wherein the downward protrusion height of the first hump surface is greater than the downward protrusion thickness of the second hump surfaces. In other possible implementations, it can also include multiple third hump surfaces, multiple fourth hump surfaces, etc., arranged sequentially on the first surface 21 of the pressure plate with the center location as the center, and the protrusion height decreasing sequentially. This embodiment is only an example and is not limited to this. For example, multiple second humps, third humps, etc., can be arranged into other shapes, such as squares, regular polygons, pentagons, etc.

[0063] Example 2

[0064] According to the end plate strength testing method provided by the present invention, based on the end plate strength testing device of Embodiment 1, a testing device capable of applying pressure is also employed, comprising the following steps:

[0065] Step S1: Place the base 1 of the end plate strength testing device on the platform of the testing equipment. The pressure range that the testing equipment can apply is preferably 0-100000N.

[0066] Step S2: Place the end plate 3 on the support member 12 and adjust the distance between the two support members 12 so that the strap mating area 31 mates with the arc surface 1211.

[0067] Step S3: Place the pressure plate 2 on the end plate 3, with the center of the first surface 21 of the pressure plate corresponding to the center of the upper surface of the end plate 3.

[0068] Step S4: Place the pressure head of the test equipment at the center of the second surface 22 of the pressure plate, so that the center of the pressure head, the pressure plate 2 and the end plate 3 are on the same vertical line, so that the module expansion force applied by the pressure plate 2 to the end plate 3 is consistent with the expansion force of the secondary unit in the module to the end plate 3.

[0069] Step S5: Pressurize the pressure plate 2. The initial pressure is 0N, the pressure threshold is the maximum expansion force of the battery, and the pressurization speed ranges from 0.1 to 450 mm / min. Different pressurization speeds simulate the change process of the module expansion force applied by the module to the end plate 3 under different charging rates and long-term storage conditions. The specific settings can be adjusted according to actual conditions.

[0070] Regarding the test load application process, the initial pressure is 0N, and then pressure is applied at a designed rate of V, where V ranges from 1 to 100 mm / min. There are two methods for stopping the pressure application: Method 1, the end plate 3 is directly crushed, as it cannot withstand further pressure; Method 2, based on the maximum expansion force of the secondary battery cell at the end of its lifespan, a threshold for the load applied by the test equipment is set. When the threshold is reached, the test pressure application is stopped, and then the condition of the end plate 3 is checked for cracks or debris damage. If the end plate 3 cracks, it indicates insufficient strength; if it does not crack, it indicates that the end plate 3 is strong enough to withstand the expansion force of the internal secondary battery cells of the module and can be used.

[0071] This application simulates an endplate strength test, which can be completed in a very short time, quickly verifying the endplate 3's ability to withstand module expansion forces. The testing device and process described in this application require very little equipment resources and time, significantly reducing testing costs. This allows the endplate 3 to be quickly and fully verified to be free of breakage risks before being implemented in the project, which is of great significance for rapidly advancing project development.

[0072] Working principle

[0073] Place the base 1 of the end plate strength testing device on the platform of the testing equipment. The pressure range that the testing equipment can apply is preferably 0-100000N. Place the end plate 3 on the support member 12 and adjust the distance between the two support members 12 so that the binding strap mating area 31 mates with the arc surface 1211. Place the pressure plate 2 on the end plate 3, with the center of the first surface 21 of the pressure plate corresponding to the center of the upper surface of the end plate 3. Place the pressure head of the testing equipment at the center of the second surface 22 of the pressure plate, so that the center of the pressure head, the pressure plate 2, and the end plate 3 are on the same vertical line, so that the module expansion force applied by the pressure plate 2 to the end plate 3 is consistent with the expansion force of the secondary single cell in the module to the end plate 3. Pressurize the pressure plate 2 with an initial pressure of 0N and a pressure threshold of the maximum expansion force of the battery. The pressurization speed range is 0.1-450mm / min. If end plate 3 breaks, it means that the strength of end plate 3 is insufficient; if end plate 3 does not break, it means that the strength of end plate 3 can withstand the expansion force of the internal secondary battery cells of the module and it can be used.

[0074] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0075] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. An end plate strength testing device, characterized in that, Includes a base (1) and a pressure plate (2); The base (1) includes a support member (12), the top of the support member (12) is recessed downward to form a support member mating surface (121), the support member mating surface (121) is used to place the strap mating area (31) at the bottom of the end plate (3). The pressure plate (2) includes a first pressure plate surface (21), which is used to abut against the upper surface of the end plate (3), and the center of the first pressure plate surface (21) is correspondingly set with the center of the upper surface of the end plate (3); the pressure plate (2) also includes a second pressure plate surface (22) opposite to the first pressure plate surface (21), which is used to transfer the load applied by the test equipment to the end plate (3); The first surface (21) of the pressure plate is a multi-hump surface, which is used to simulate the expansion of the secondary battery in different locations over a large area; The support mating surface (121) includes an arc surface (1211) and a relief groove (1212), the shape of which matches the strap mating area (31); The maximum height of the protrusion on the first surface (21) of the pressure plate is G, and the thickness of the secondary battery cell is H, 0.35H≥G≥0.002H; The depth of the clearance groove (1212) shall not exceed 10 times the width of the support mating surface (121) and shall not be less than 0.1 times the width of the support mating surface (121).

2. The end plate strength testing device as described in claim 1, characterized in that, The multi-hump surface forms multiple hemispherical protrusions downward from the first surface (21) of the pressure plate, and the multi-hump surface includes two or more hump surfaces.

3. The end plate strength testing device as described in claim 1, characterized in that, The width of the strap mating area (31) is 0.1-20 mm larger than the width of the support mating surface (121).

4. The end plate strength testing device as described in claim 1, characterized in that, The base (1) also includes a mounting base (11), which has multiple mounting holes, and the support (12) can be installed at different positions on the mounting base (11) through different mounting holes.

5. The end plate strength testing device as described in claim 4, characterized in that, Two support members (12) are installed on the mounting base (11) respectively. Two sets of strap mating areas (31) are symmetrically arranged on the end plate (3). The distance between the two support members (12) is consistent with the distance between the two sets of strap mating areas (31).

6. A method for testing the strength of an end plate, characterized in that, The end plate strength testing device according to any one of claims 1-5 also employs a testing device capable of applying pressure, comprising the following steps: Step S1: Place the base (1) of the end plate strength testing device on the platform of the testing equipment; Step S2: Place the end plate (3) on the support member (12) and adjust the distance between the two support members (12) so that the strap mating area (31) mates with the support member mating surface (121); Step S3: Place the pressure plate (2) on the end plate (3); Step S4: Place the pressure head of the test device at the center of the second surface (22) of the pressure plate, so that the centers of the pressure head, the pressure plate (2) and the end plate (3) are on the same vertical line; Step S5: Pressurize the pressure plate (2) with an initial pressure of 0 N, a pressure threshold of the maximum expansion force of the battery, and a pressurization speed ranging from 0.1 to 450 mm / min.

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