A device for detecting the tightness of the fit between the cover plate and the aluminum shell.

Abstract

This utility model relates to a device for detecting the tightness of the fit between a cover plate and an aluminum shell, solving the problem of distorted test data caused by inaccurate fixture positioning in the prior art when detecting the tightness between the aluminum shell and the cover plate of a lithium battery. The technical solution includes a force gauge, a force gauge fixing base, a lower mold assembly, and an upper mold assembly. The lower mold assembly includes a lower mold base fixed on the force gauge fixing base and a lower mold plate fixedly connected to the lower mold base. The upper mold assembly includes a tension rod fixing frame, a tension rod, and a tension block. The tension rod passes through the tension rod fixing frame, and the tension rod and the tension block are movably connected by a first positioning pin. The tension block can rotate around the first positioning pin. The force gauge is connected to the force gauge fixing base and is located above the tension rod fixing frame. The force application rod at the lower end of the force gauge is fixedly connected to the tension rod fixing frame.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing and testing technology, specifically to a device for detecting the tightness of the fit between the cover plate and the aluminum shell. Background Technology

[0002] In lithium battery production, the tightness of the fit between the cover plate and the aluminum shell is a key indicator affecting the battery's sealing performance and structural safety. Before welding, the cover plate must be pressed into the aluminum shell. If the cover plate is too small, the fit between it and the aluminum shell will be too loose (i.e., the friction between the edge of the cover plate and the aluminum shell will be too small). In this case, during the assembly process, the cover plate is easily pushed out by the battery cells in the aluminum shell, thus affecting the subsequent assembly process. Therefore, the tightness of the fit between the two must be appropriate. Both too loose and too tight fits require adjustment of the dimensions of the aluminum shell and the cover plate. This is a means of production control.

[0003] Currently, most manufacturers in the industry do not effectively implement precise quantitative testing of the tightness of the fit between the cover plate and the aluminum shell. The common practice is to use an extremely primitive, subjective method to judge the fit after assembling the cover plate into the aluminum shell: inverting the component and tapping or shaking the aluminum shell to see if the cover plate will fall off, thus judging whether the fit is "qualified". This non-quantitative, subjective, and experience-based manual testing method lacks objective standards and accuracy.

[0004] The current industry-standard quantitative testing method involves using a fixture to clamp the edge of the cover plate and applying an upward tensile force with a force gauge to test the tightness between the cover plate and the aluminum shell. This testing method frequently encounters the following problems: uneven force distribution on the cover plate when clamped leads to tilting and separation, resulting in distorted tensile force data; the core mating surface between the cover plate and the aluminum shell is located around the perimeter of the pole hole, but the fixture cannot directly apply force to this area, making it impossible to accurately measure the true bonding force. Utility Model Content

[0005] This invention provides a device for detecting the tightness of the fit between the cover plate and the aluminum shell, which solves the problem of distorted test data caused by inaccurate fixture positioning in the existing technology for detecting the tightness between the aluminum shell and the cover plate of lithium batteries, and improves the accuracy of the detection.

[0006] The technical solution of this utility model is as follows: it includes a tensile gauge, a tensile gauge fixing base, a lower mold assembly, and an upper mold assembly; The lower mold assembly includes a lower mold base fixed to the tension gauge mounting base, and a lower mold plate fixedly connected to the lower mold base. The upper mold assembly includes: a tension rod fixing frame, a tension rod, and a tension block. The tension rod passes through the tension rod fixing frame, and the tension rod and the tension block are movably connected by a first positioning pin. The tension block can rotate around the first positioning pin. The force gauge is connected to the force gauge mounting base and is located above the force rod mounting bracket. The force application rod at the lower end of the force gauge is fixedly connected to the force rod mounting bracket.

[0007] Preferably, the tension rod fixing frame has a first connecting hole in the middle for connecting with the tension gauge, and second connecting holes are respectively opened on both sides of the first connecting hole. The upper end of the tension rod passes through the second connecting hole, and the lower end is connected to the tension block.

[0008] Preferably, on the tension rod fixing bracket, a plurality of second connection holes are provided on both sides of the first connection hole, and the second connection holes on both sides are symmetrically distributed about the center of the first connection hole. Two oppositely arranged notches are opened on the lower side of the tension rod, and the two notches extend to the lower end face of the tension rod, and the planes of the two notches are parallel to each other. A through hole perpendicular to the axial direction of the tension rod is opened on the tension rod body between the two notches. A through hole is also opened in the middle of the tension block. The first positioning pin passes through the through holes of the tension rod and the tension block to connect the tension block and the tension rod.

[0009] Preferably, a counterweight is provided on one side of the middle section of the tension block. The mass of the counterweight is greater than the mass of the tension block body, the length of the tension block is greater than the diameter of the pole hole on the cover plate, and the maximum width and thickness are both less than the radius of the pole hole on the cover plate. Preferably, the lower template and the lower mold base are locked together by screws. The surface of the lower template is provided with a contoured positioning cavity that matches the bottom contour of the aluminum shell. The outer side of the lower template is provided with multiple horizontal threaded holes. A second positioning pin is provided in the threaded holes. The second positioning pin is provided with external threads and its front end can extend into the contoured positioning cavity.

[0010] Preferably, the lower template has multiple positioning holes, and the lower mold base is provided with alignment pins that correspond one-to-one with the positioning holes. The alignment pins extend into the positioning holes of the lower template to position the lower template.

[0011] Preferably, the top end of the tension rod is connected to the tension rod fixing bracket by a thread.

[0012] Preferably, the tension gauge mounting base is an L-shaped bracket, the tension gauge is mounted on the vertical section of the tension gauge mounting base, and the lower mold base is mounted on the upper surface of the horizontal section of the tension gauge mounting base.

[0013] The beneficial effects of this utility model are as follows: 1. By rotating the tension block to engage the lower edge of the cap plate pole hole, the actual stress point is accurately reproduced; at the same time, the lower template contour positioning cavity ensures the true position of the aluminum shell, effectively improving the accuracy of test data.

[0014] 2. The lower mold assembly is precisely positioned using pins to eliminate assembly errors and ensure consistent testing standards; the aluminum shell is locked with horizontal screws to prevent displacement during testing and ensure that the tensile force direction is vertical; the L-shaped fixing seat provides stable support and prevents deformation under force.

[0015] 3. It adopts a modular design, in which the contour positioning cavity, tension rod, and tension block can all be replaced. The tension rod fixing bracket is equipped with multiple second positioning holes, which can adjust the distance between the two tension rods according to the spacing of the terminal holes of different lithium batteries, so as to be suitable for testing different types of lithium batteries.

[0016] 4. In this application, by setting a counterweight on one side of the pulling block, the pulling block can naturally rotate to a horizontal state under the action of the counterweight without the application of external force after entering the terminal hole of the lithium battery cover plate. This avoids the problem of needing human intervention to make the pulling block flip in the terminal hole, and improves the convenience of the entire device during use. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the device provided in an embodiment of the present utility model; Figure 2 This is an exploded view of the upper mold assembly provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the upper mold assembly provided in this embodiment of the present invention, showing the tension block in a vertical position. Figure 4 This is a schematic diagram of the upper mold assembly provided in this embodiment of the present invention, showing the tension block in a horizontal state. Figure 5 This is a schematic diagram of the tension block structure provided in an embodiment of the present utility model; Figure 6 This is a schematic diagram of the structure of the lower mold assembly provided in an embodiment of the present utility model; Figure 7 A schematic diagram of the working state of the device provided in the embodiment of this utility model.

[0018] The attached figures are labeled as follows: 1. Force gauge mounting base; 2. Force gauge; 3. Lower mold base; 4. Second positioning pin; 5. Lower template; 51. Positioning hole; 52. Screw; 6. Tension rod fixing bracket; 61. First connecting hole; 62. Second connecting hole; 7. Tension rod; 8. First positioning pin; 9. Tension block; 10. Upper mold assembly; 11. Cover plate; 12. Aluminum shell; 13. Lower mold assembly; L, tension block length; H, maximum width of tension block; D, tension block thickness. Detailed Implementation

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0020] like Figure 1 The testing device shown includes a force gauge 2, a force gauge mounting base 1, a lower mold assembly 13, and an upper mold assembly 10. The lower mold assembly 13 includes a lower mold base 3 fixed on the force gauge mounting base 1 and a lower mold plate 5 fixedly connected to the lower mold base 3. The upper mold assembly 10 includes a tension rod mounting bracket 6, a tension rod, and a tension block 9. The tension rod 7 passes through the tension rod mounting bracket 6, and the tension rod 7 and the tension block 9 are movably connected by a first positioning pin 8. The tension block 9 can rotate around the axis of the first positioning pin 8. The force gauge 2 is connected to the force gauge mounting base 1 and is located above the tension rod mounting bracket. The force application rod at the lower end of the force gauge 2 is fixedly connected to the tension rod mounting bracket 6.

[0021] like Figure 2 and Figure 4 As shown, the tension rod fixing bracket 6 has a first connecting hole 61 in the middle for connecting with the tension gauge, and second connecting holes 62 are respectively opened on both sides of the first connecting hole 61. The upper end of the tension rod 7 passes through the second connecting hole 62, and the lower end is connected to the tension block 9.

[0022] On the tension rod fixing bracket 6, multiple second connection holes 62 are provided on both sides of the first connection hole 61, and the second connection holes 62 on both sides are symmetrically distributed with the center of the first connection hole 61 as the center. The tension rod 7 can be fixed in different second connection holes according to different needs (loosen the threaded connection, pull the tension rod out of the current hole, insert it into another hole, and then tighten the thread to fix it). Two opposing notches are opened on the lower side of the tension rod 7, which extend to the lower end face of the tension rod 7, and the planes of the two notches are parallel to each other. A through hole perpendicular to the axial direction of the tension rod 7 is opened on the tension rod body between the two notches. A through hole is also opened in the middle of the tension block 9. The first positioning pin 8 is inserted into the through holes of the tension rod 7 and the tension block 9 to connect the tension block 9 and the tension rod 7, ensuring that the tension block 7 can rotate without obstruction after the tension block 9 and the tension rod 7 are fixedly connected.

[0023] like Figure 4-5As shown, when the tension block 9 is in a horizontal state, its length direction is perpendicular to the axis of the tension rod 7, and the protruding parts on both sides form a cantilever support structure. In this embodiment, the length of the tension block is greater than the diameter of the pole hole on the cover plate 11 to ensure that the tension block 9 can be engaged with the lower edge of the pole hole on the cover plate when in a horizontal state. A counterweight 901 is provided on one side of the middle section of the tension block 9. The mass of the counterweight 901 is greater than the mass of the tension block body, so that the tension block 9 can be in a horizontal state in a free state. When the tension block is manually adjusted from a horizontal state to a vertical state (e.g., ...), the tension block can be adjusted to a horizontal state. Figure 3 After being inserted into the hole of the cap plate pole (as shown), the tension block can then return from a vertical state to a horizontal state under its own weight. In this embodiment, the tension block body can preferably be made of high-strength plastic (such as PPA material) or other hard metal materials, and the counterweight can be made of solid carbon steel, so as to ensure that the strength of the tension block meets the requirements of this embodiment and that the weight of the counterweight is greater than the weight of the tension block body.

[0024] In this embodiment, the lower template 5 is positioned by a pin and then locked to the lower mold base 3 by screws 52. The surface of the lower template 5 is provided with a contoured positioning cavity that matches the bottom contour of the aluminum shell 12. The outer side of the lower template 5 has multiple horizontal threaded holes. The second positioning pin 4 has a smooth front end that extends into the contoured positioning cavity and an external threaded part for screwing into the threaded hole. Its front end can extend into the contoured positioning cavity to assist in fixing the position of the aluminum shell 12 during testing. Further explanation of the rationality of using positioning pins for fixing: The aluminum shell is formed by stretching. Stretching the aluminum shell generates a lot of heat. After forming, the upper part will shrink by 0.1mm due to thermal expansion and contraction. The bottom is supported by raw materials, so the size is relatively stable and the strength is relatively large. Moreover, the maximum measured tensile force will not exceed 50N. Therefore, the aluminum shell is locked by using the second positioning pin. During the measurement process, the second positioning pin will not come loose. After the measurement is completed, the tested aluminum shell will be scrapped.

[0025] The lower template 5 has multiple positioning holes 51, and the lower mold base 3 is provided with alignment pins that correspond one-to-one with the positioning holes. The alignment pins extend into the positioning holes 51 of the lower template to position the lower template.

[0026] In this embodiment, the force gauge preferably adopts the HT-50 digital display push-pull force gauge, with a range of 0-50N and an accuracy of ±0.5%.

[0027] The preferred mounting base for the force gauge is a push-pull force gauge of model WVEas50j.

[0028] In this embodiment, the connection method between the tension rod and the tension rod fixing frame is described as follows: The top end of the tension rod 7 can be detachably connected to the tension rod fixing bracket 6 via threads, or an annular boss can be provided on the upper end of the tension rod. Instead of using threads to connect the tension rod and the tension rod fixing bracket, the tension rod is directly passed through the second connecting hole on the tension rod fixing bracket and hung on the tension rod fixing bracket after being limited by the annular boss.

[0029] The tension gauge mounting base 1 is an L-shaped bracket with a vertical lifting device on its vertical section. In this embodiment, a screw and nut pair is used, driven by a handwheel, and the tension gauge 2 is fixed at the end of the screw by bolts. The horizontal section of the tension gauge mounting base 1 is provided with a platform for the installation of the lower mold assembly 13.

[0030] The specific working principle of this embodiment is as follows: During the preparation stage, first rotate the handwheel to raise the upper mold assembly, place the aluminum shell 12 into the contour positioning cavity of the lower mold plate 5, then tighten the second positioning pin 4 on the side to fix the shell, complete the clamping of the aluminum shell 12, select the second connecting hole of the matching cover plate, and insert the tension rod.

[0031] After adjusting the tension block to a vertical position, pass it through the cover plate pole hole. Once inserted, the tension block will rotate back to a horizontal position under its own weight (counterweight 901 remains downward). Adjust the handwheel so that the tension block abuts against the inner lower edge of the cover plate pole hole to complete the clamping work.

[0032] During testing, the digital tensile tester is pre-set with a tension value. Turning the handwheel causes the tension block to rise at a constant speed. If the cover plate does not detach from the aluminum shell when the tension value is reached, the fit between the cover plate and the aluminum shell is considered acceptable. Conversely, if the cover plate detaches from the aluminum shell before the tension value is reached, the fit between the cover plate and the aluminum shell is insufficient, indicating a defective product.

[0033] It should be noted that the above testing process is not applied to all aluminum casings and covers of lithium batteries. Rather, it is conducted on samples before mass production; only those samples that pass the inspection are put into mass production.

[0034] To switch to different battery models for testing, the pull rod 7 can be removed, the pull block 9 of the corresponding length can be replaced, the pull rod can be installed into the second connecting hole of the corresponding position, and the lower template 5 of the corresponding contour positioning cavity can be replaced. After the replacement is completed, the above operation can be repeated. This can significantly improve the testing efficiency, greatly reduce the damage rate of the cover plate, and ensure the high accuracy and repeatability of the test results.

[0035] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cover plate and aluminum shell fit tightness detection device, characterized in that, Includes a force gauge, a force gauge mounting base, a lower die assembly, and an upper die assembly; The lower mold assembly includes a lower mold base fixed to the tension gauge mounting base, and a lower mold plate fixedly connected to the lower mold base. The upper mold assembly includes: a tension rod fixing frame, a tension rod, and a tension block. The tension rod passes through the tension rod fixing frame, and the tension rod and the tension block are movably connected by a first positioning pin. The tension block can rotate around the first positioning pin. The force gauge is connected to the force gauge mounting base and is located above the force rod mounting bracket. The force application rod at the lower end of the force gauge is fixedly connected to the force rod mounting bracket.

2. The cover plate and aluminum case fit tightness detection device according to claim 1, characterized in that, The tension rod fixing frame has a first connecting hole in the middle for connecting with the tension gauge, and second connecting holes are respectively opened on both sides of the first connecting hole. The upper end of the tension rod passes through the second connecting hole, and the lower end is connected to the tension block.

3. The cover plate and aluminum case fit tightness detection device according to claim 2, characterized in that, On the tension rod fixing bracket, multiple second connection holes are provided on both sides of the first connection hole, and the second connection holes on both sides are symmetrically distributed with the center of the first connection hole as the center. Two opposite notches are opened on the lower side of the tension rod, and the two notches extend to the lower end face of the tension rod, and the planes of the two notches are parallel to each other. A through hole perpendicular to the axial direction of the tension rod is opened on the tension rod body between the two notches. A through hole is also opened in the middle of the tension block. The first positioning pin passes through the through holes of the tension rod and the tension block to connect the tension block and the tension rod.

4. The cover plate and aluminum case fit tightness detection device according to claim 3, characterized in that, A counterweight is provided on one side of the middle section of the tension block. The mass of the counterweight is greater than the mass of the tension block body. The length of the tension block is greater than the diameter of the pole hole on the cover plate. The maximum width and thickness are both less than the radius of the pole hole on the cover plate.

5. The cover plate and aluminum case fit tightness detection device according to claim 1, characterized in that, The lower template and the lower mold base are locked together by screws. The surface of the lower template is provided with a contoured positioning cavity that matches the bottom contour of the aluminum shell. The outer side of the lower template is provided with multiple horizontal threaded holes. A second positioning pin is provided in the threaded hole. The second positioning pin is provided with external threads and its front end can extend into the contoured positioning cavity.

6. The cover plate and aluminum case fit tightness detection device according to claim 1, characterized in that, The lower template has multiple positioning holes, and the lower mold base is provided with alignment pins that correspond one-to-one with the positioning holes. The alignment pins extend into the positioning holes of the lower template to position the lower template.

7. The cover plate and aluminum case fit tightness detection device according to claim 1, characterized in that, The top end of the tension rod is connected to the tension rod fixing frame by a thread.

8. The cap and aluminum shell fit tightness detection device of claim 1, wherein, The tension gauge mounting base is an L-shaped bracket, with the tension gauge mounted on the vertical section of the tension gauge mounting base and the lower mold base mounted on the upper surface of the horizontal section of the tension gauge mounting base.

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