Tension test method and tension test structure for a battery top cover assembly
By setting a tension band in the battery top cover assembly and conducting a tensile test, the problem of not being able to accurately measure the critical strength of the connection structure between the battery top cover assembly and the battery cell in the existing technology is solved, achieving accurate test results and an efficient test process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BATTEROTECH CO LTD
- Filing Date
- 2026-05-27
- Publication Date
- 2026-07-14
Smart Images
Figure CN122385337A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery testing technology, specifically to a tensile testing method and structure for a battery top cover assembly. Background Technology
[0002] During battery manufacturing, the battery cell needs to be encapsulated in an aluminum battery casing. A top cover and terminals are then installed at the end of the casing to connect the battery cell to the external circuitry. During assembly, the insulating sheet at the end of the battery cell is heat-welded to the lower plastic casing, which is then fixed to the bottom surface of the top cover. The top surface of the top cover also contains terminals and other structures. These structures together form the battery's top cover assembly.
[0003] In subsequent battery reliability testing, the reliability between the top cover assembly and the battery cell needs to be tested. Specifically, in the prior art, when conducting reliability testing between the top cover assembly and the battery cell, each component is usually tested separately. For example, the pull-out strength of the lower plastic and the insulating sheet is tested separately, and the material strength of the lower plastic is tested separately.
[0004] However, the above tests can only reflect the strength of a single component. Depending on the connection location and connection method, the stress on each component will be different. Therefore, the above tests cannot accurately measure the critical strength of the connection structure formed by the top cover assembly and the battery cell.
[0005] Therefore, there is an urgent need to provide a reliability testing structure and method that can more accurately measure the critical strength of the connection structure formed by the battery cover assembly and the battery cell. Summary of the Invention
[0006] The purpose of this application is to provide a tensile testing method and structure for a battery top cover assembly, which can more accurately measure the critical strength of the connection structure formed by the battery top cover assembly and the battery cell.
[0007] To achieve the above objectives, in a first aspect, this application provides a tensile testing method for a battery top cover assembly, the tensile testing method comprising: A tension band is fitted into the assembly gap between the top cover and the lower plastic. In the battery top cover assembly, the lower plastic is fixed to the top cover and the lower plastic is fixed to the cell insulation sheet. The tensile testing machine is used to clamp the bare battery cell insulation sheet and the tensile band respectively; Control the tensile testing machine to perform a tensile test between the lower plastic and the top cover.
[0008] Based on the embodiments described above, in specific testing, the top cover, lower plastic, and cell insulating sheet are connected to form a battery top cover assembly. This connection structure is consistent with the connection structure used in specific applications of the battery top cover assembly. Subsequently, a tension band is passed through the gap between the top cover and the lower plastic to conduct a tensile test without damaging the original connection structure, thereby enabling the test results to more accurately reflect the failure status of the battery top cover assembly under stress.
[0009] In summary, the test structure described in this application can accurately simulate the actual working conditions of each component during cell assembly, resulting in more accurate and reliable test results. Compared to testing each component individually, it can more realistically reflect the failure status of each component under actual working conditions. Furthermore, by incorporating a tension band, a stable and reliable clamping structure is provided for the grippers of the tensile testing machine without damaging the connection structure of the components, making the overall testing process simple and quick.
[0010] In some embodiments, during the tensile test, the tensile testing machine stretches the battery top cover assembly along a first direction until tensile failure occurs, while simultaneously recording the tensile displacement curve of the tensile testing machine and the failure location of the battery top cover assembly, wherein the first direction is the height direction of the battery.
[0011] Based on the embodiments described above and the tensile testing method described above, the tensile displacement curve of the tensile testing machine is recorded. This curve can intuitively reflect the relationship between the tensile force applied by the tensile testing machine when performing a tensile test on the battery top cover assembly and the deformation of the battery top cover assembly. This allows for accurate and complete recording of the tensile testing process.
[0012] In some embodiments, during the tensile test, the first peak of the tensile displacement curve is the critical strength of the connection structure of the battery top cover assembly, thereby determining the critical strength and failure location of the battery top cover assembly.
[0013] Based on the embodiments described above, the tensile test results can be clearly reflected by recording the tensile-displacement curve. The peak value of the tensile-displacement curve represents the moment when the displacement suddenly increases, which is also the moment when the battery top cover assembly fails. Therefore, the tensile force value at the time of battery top cover assembly failure can be clearly measured.
[0014] In some embodiments, the tensile testing step involves a tensile rate of 10 mm / min to 100 mm / min.
[0015] Based on the above embodiments of this application, by limiting the tensile rate, which is within a quasi-static tensile state, the deformation and failure process of the material can be made to ignore the inertial effect, thereby enabling the measurement results to more accurately and reliably reflect the actual failure of the above-mentioned connection structure.
[0016] According to a second aspect of this application, a tensile testing structure for a battery top cover assembly is provided, applicable to the aforementioned tensile testing method for the battery top cover assembly. The tensile testing structure includes a cell insulating sheet, a top cover, a lower plastic sheet, and a tensile band. The lower plastic sheet is fixed to the top cover, the top cover is disposed at the end of the battery, and the lower plastic sheet is connected to the cell insulating sheet. The tensile band passes between the top cover and the lower plastic sheet, with both ends of the tensile band converging in a direction away from the battery. A tensile testing machine clamps the ends of the cell insulating sheet and the tensile band, respectively.
[0017] Based on the above embodiments of this application, a tensile testing structure for a battery top cover assembly is provided. The structure consists of a cell insulating sheet, a top cover, and a lower plastic sheet, forming a complete test connection structure. The connection method of this test connection structure is consistent with the specific application of the above structure in the cell, and can accurately simulate the actual connection situation of the above structure during cell assembly.
[0018] A tension band is then installed between the top cover and the lower plastic section, and both ends of the tension band are pulled away from the battery and brought together to form a free end for clamping. During clamping, the two jaws of the tensioning machine grip the battery and the tension band respectively, with the tension band providing a convenient clamping end for the jaws.
[0019] Through the above-mentioned settings in this application, a series test model consistent with the actual force path of the battery top cover assembly is constructed, ensuring that the force direction and constraint conditions during the test are highly consistent with the actual working conditions, and the test results have extremely high engineering simulation value and accuracy.
[0020] Furthermore, since the battery cell insulation sheet, lower plastic, and top cover are connected together in this application, compared to testing each component separately, the test structure described above can cause the weakest connection point in the entire mechanical transmission chain to fail first during a single tensile test, thereby accurately identifying the weakest location in the connection structure. Moreover, the test structure described above is simple in overall design and easy to clamp, with a short testing cycle, enabling rapid testing of a large number of samples, significantly reducing testing costs and improving testing efficiency.
[0021] In summary, the test structure described in this application can accurately simulate the actual working conditions of each component during cell assembly, resulting in more accurate and reliable test results. Compared to testing each component individually, it can more realistically reflect the failure status of each component under actual working conditions. Furthermore, by incorporating a tension band, a stable and reliable clamping structure is provided for the grippers of the tensile testing machine without damaging the connection structure of the components, making the overall testing process simple and quick.
[0022] In some embodiments, at least one tension band is provided, and the tension bands are symmetrically arranged along the length direction of the battery.
[0023] Based on the embodiments described above, one or more tension bands can be provided. When only one tension band is provided, it is positioned at the midpoint of the battery's length direction, thus achieving symmetrical arrangement along the battery's length direction. When two tension bands are provided, they are symmetrically arranged along the battery's length direction. Similarly, as the number of tension bands continues to increase, the tension bands as a whole still need to be symmetrically arranged along the battery's length direction.
[0024] By symmetrically positioning the tension band along the length of the battery, the tensile force can be evenly transmitted between the top cover and the lower plastic layer during testing. This also prevents the battery from shifting to one side during measurement, thus avoiding any impact on the accuracy of the test results.
[0025] In some embodiments, the width of the tension band is set to 10mm-50mm.
[0026] Based on the embodiments described above, the width of the tension band is limited to ensure sufficient load-bearing cross-sectional area, guaranteeing its strength and enabling it to withstand the tensile force required during testing without tearing or premature breakage. This limits the failure location to the connection structure of the battery top cover assembly, thereby ensuring the authenticity and validity of the test data.
[0027] Meanwhile, by limiting the width of the tension band, an appropriate width avoids assembly difficulties caused by an excessively wide band, while also preventing stress concentration in localized areas and premature tearing of the tested structure due to an excessively narrow band. This width range ensures that the tensile force can be applied evenly and concentratedly to the connection structure between the top cover and the lower plastic, allowing the measured tensile force to accurately reflect the actual strength of the connection structure.
[0028] In some embodiments, the lower plastic is symmetrically arranged along the length of the battery, and the cell insulating sheet is correspondingly arranged with the lower plastic. The cell insulating sheet is fixed to the lower plastic by thermoforming welding, and the lower plastic is fixed to the top cover by any one of the following methods: snap-fit, ultrasonic welding, or interference fit.
[0029] Based on the embodiments described above, by symmetrically arranging the lower plastic along the length of the battery and correspondingly arranging the cell insulation sheet with the lower plastic, the stress distribution of the entire test structure is ensured to have geometric symmetry. During the tensile process, the tensile force can be evenly transmitted to each connection point, avoiding stress concentration caused by connection position offset, thus making the measurement results more accurate and reliable.
[0030] Meanwhile, the connection methods between the cell insulation sheet and the lower plastic, as well as the connection methods between the lower plastic and the top cover, are consistent with the connection methods of the above-mentioned components in the actual battery assembly, thereby more accurately simulating the stress conditions of the above-mentioned components under actual working conditions and further improving the accuracy of the test.
[0031] In some embodiments, the breaking force of the tension band is greater than the breaking force of the battery cell insulation sheet and the breaking force of the lower plastic.
[0032] Based on the embodiments described above, when the above structure is specifically connected, the cell insulating sheet and the lower plastic serve as the connection structure between the top cover and the battery. Therefore, in the event of failure, the failure location is usually at the connection point of the above components or on the cell insulating sheet and the lower plastic. By limiting the tensile strength of the tension band to be higher than that of the cell insulating sheet and the lower plastic, it is ensured that the tension band will not break before the cell insulating sheet and the lower plastic during the test. This ensures that the measured failure location and critical strength are the strength of the weakest point in the connection structure formed by the top cover assembly and the battery, thereby ensuring the reliability of the measurement results.
[0033] In some embodiments, the tension band and the cell insulation sheet are made of the same material.
[0034] Based on the above embodiments of this application, the tension band and the battery cell insulation sheet are made of the same material. In the specific production and preparation process, they can be directly prepared together with the battery cell insulation sheet using the same process, thereby reducing production and processing costs and improving production and processing efficiency.
[0035] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description
[0036] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the tensile testing method for the battery top cover assembly provided in this application embodiment.
[0037] Figure 2 This is a schematic diagram of the tensile testing structure of the battery top cover assembly provided in the embodiments of this application.
[0038] Figure 3 This is a schematic diagram of the structure of the cell insulating sheet, the top cover, and the tensile band in the tensile test structure of the battery top cover assembly provided in the embodiments of this application.
[0039] Figure 4 This is a schematic diagram of the structure of the cell insulating sheet, top cover and lower plastic in the tensile test structure of the battery top cover assembly provided in the embodiments of this application.
[0040] Explanation of reference numerals in the attached figures 1. Insulating sheet for battery cell; 2. Top cover; 3. Lower plastic sheet; 4. Tension band; 5. Upper clamp; 6. Lower clamp. Detailed Implementation
[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0043] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0045] In the description of this application, it should be noted that, unless otherwise stated, the terms "inner," "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used 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, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0046] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0047] During battery manufacturing, the battery cell needs to be encapsulated in an aluminum battery casing. A top cover and terminals are then installed at the end of the casing to connect the battery cell to the external circuitry. During assembly, the battery cell's insulating sheet is heat-welded to the lower plastic casing, which is then fixed to the bottom surface of the top cover. The top surface of the top cover also contains terminals and other structures. These structures together form the battery's top cover assembly.
[0048] In subsequent battery reliability testing, the reliability between the top cover assembly and the battery cell needs to be tested. Specifically, in the prior art, when conducting reliability testing between the top cover assembly and the battery cell, each component is usually tested separately. For example, the pull-out strength of the lower plastic and the battery cell insulation sheet are tested separately, and the material strength of the lower plastic is tested separately.
[0049] However, the above tests can only reflect the strength of a single component. Depending on the connection location and connection method, the stress on each component will be different. Therefore, the above tests cannot accurately measure the critical strength of the connection structure formed by the top cover assembly and the battery cell.
[0050] Therefore, there is an urgent need to provide a reliability testing structure and method that can more accurately measure the critical strength of the connection structure formed by the battery cover assembly and the battery cell.
[0051] To address the aforementioned problems in the prior art, embodiments of this application provide a tensile testing method for a battery top cover assembly, referring to... Figure 1 As shown, the tensile testing method includes: S001 The tension band 4 is fitted into the assembly gap between the top cover 2 and the lower plastic 3. In the battery top cover assembly, the lower plastic 3 is fixed to the top cover 2 and the lower plastic 3 is fixed to the cell insulation sheet 1. S002 controls the tensile testing machine to clamp the bare battery cell insulation sheet 1 and the tensile belt 4 respectively; S003 controls the tensile testing machine to perform a tensile test between the lower plastic 3 and the top cover 2.
[0052] Based on the above embodiments of this application, during specific testing, the top cover 2, the lower plastic 3, and the cell insulating sheet 1 are connected to form a battery top cover assembly. This connection structure is consistent with the connection structure of the battery top cover assembly in specific applications. Subsequently, the tension band 4 passes through the gap between the top cover 2 and the lower plastic 3 to conduct a tensile test without damaging the original connection structure, thereby enabling the test results to more accurately reflect the failure status of the battery top cover assembly under stress.
[0053] In summary, the test structure described in this application can accurately simulate the actual working conditions of each component during battery cell assembly, resulting in more accurate and reliable test results. Compared to testing each component individually, it can more realistically reflect the failure status of each component under actual working conditions. Furthermore, by setting up the tension band 4, a stable and reliable clamping structure is provided for the grippers of the tensile testing machine without damaging the connection structure of the components, making the overall testing process simple and quick.
[0054] In some embodiments of this application, during the tensile test, the tensile testing machine stretches the battery top cover assembly along a first direction until tensile failure occurs, while recording the tensile displacement curve of the tensile testing machine and the failure location of the battery top cover assembly, wherein the first direction is the height direction of the battery.
[0055] Based on the embodiments described above and the tensile testing method described above, the tensile displacement curve of the tensile testing machine is recorded. This curve can intuitively reflect the relationship between the tensile force applied by the tensile testing machine when performing a tensile test on the battery top cover assembly and the deformation of the battery top cover assembly. This allows for accurate and complete recording of the tensile testing process.
[0056] In some embodiments of this application, during the tensile test, the first peak of the tensile displacement curve is the critical strength of the connection structure of the battery top cover assembly, thereby determining the critical strength and failure location of the battery top cover assembly.
[0057] Based on the embodiments described above, the tensile test results can be clearly reflected by recording the tensile-displacement curve. The peak value of the tensile-displacement curve represents the moment when the displacement suddenly increases, which is also the moment when the battery top cover assembly fails. Therefore, the tensile force value at the time of battery top cover assembly failure can be clearly measured.
[0058] In some embodiments of this application, the tensile testing step involves a tensile rate of 10 mm / min to 100 mm / min.
[0059] Based on the above embodiments of this application, by limiting the tensile rate, which is within a quasi-static tensile state, the deformation and failure process of the material can be made to ignore the inertial effect, thereby enabling the measurement results to more accurately and reliably reflect the actual failure of the above-mentioned connection structure.
[0060] Specifically, in actual testing, the tensile testing machine can be set to multiple specific rates such as 10mm / min, 20mm / min, 40mm / min, 60mm / min, 80mm / min, and 100mm / min. This application does not impose any specific restrictions on these rates.
[0061] Based on the above technical solutions, this application also provides a tensile testing structure for a battery top cover assembly, applicable to the aforementioned tensile testing method for the battery top cover assembly. (Reference) Figures 2 to 4 As shown, the tensile testing structure includes a cell insulating sheet 1, a top cover 2, a lower plastic sheet 3, and a tensile band 4. The lower plastic sheet 3 is fixed to the top cover 2, which is located at the end of the battery, and the lower plastic sheet 3 is connected to the cell insulating sheet 1. The tensile band 4 passes between the top cover 2 and the lower plastic sheet 3, with both ends of the tensile band 4 converging in the direction away from the battery. A tensile testing machine clamps the cell insulating sheet 1 and the ends of the tensile band 4 respectively.
[0062] Based on the above embodiments of this application, a tensile test structure for a battery top cover assembly is provided. The structure consists of a cell insulating sheet 1, a top cover 2, and a lower plastic 3 connected to form a complete test connection structure. The connection method of this test connection structure is consistent with the specific application of the above structure in the cell, and can accurately simulate the actual connection situation of the above structure during cell assembly.
[0063] Then, a tension band 4 is installed between the top cover 2 and the battery, and the two ends of the tension band 4 are pulled out away from the battery and brought together to form a free end that can be clamped. Then, during clamping, the two jaws of the tensioning machine clamp the battery and the tension band 4 respectively, and the tension band 4 is configured to provide an end for the jaws to clamp easily.
[0064] Through the above-mentioned settings in this application, a series test model consistent with the actual force path of the battery top cover assembly is constructed, ensuring that the force direction and constraint conditions during the test are highly consistent with the actual working conditions, and the test results have extremely high engineering simulation value and accuracy.
[0065] Meanwhile, since the battery cell insulating sheet 1, the lower plastic sheet 3, and the top cover 2 are connected together in this application, compared to testing each component separately, the test structure described above can cause the weakest connection point in the entire mechanical transmission chain to fail first during a single tensile test, thereby accurately identifying the weak point in the connection structure. Furthermore, the test structure described above is simple in overall structure and easy to clamp, with a short testing cycle, enabling rapid testing of a large number of samples, significantly reducing testing costs and improving testing efficiency.
[0066] In summary, the test structure described in this application can accurately simulate the actual working conditions of each component during battery cell assembly, resulting in more accurate and reliable test results. Compared to testing each component individually, it can more realistically reflect the failure status of each component under actual working conditions. Furthermore, by setting up the tension band 4, a stable and reliable clamping structure is provided for the grippers of the tensile testing machine without damaging the connection structure of the components, making the overall testing process simple and quick.
[0067] Furthermore, it should be noted that during assembly, the battery tensile testing structure described above in this application has the cell insulating sheet 1 completely covering the outside of the cell, and the end of the cell insulating sheet 1 is connected to the lower plastic 3. When the tensile testing machine clamps the battery, one jaw clamps the end of the tensile band 4, while the other jaw directly contacts the cell insulating sheet 1 outside the cell. Therefore, in the embodiments of this application, whether or not the cell is assembled during testing can be selected according to the actual situation. When the cell is not assembled, the cell insulating sheet 1 forms a shell structure identical to the cell structure, the tensile band 4 passes between this shell structure and the top cover 2, and the jaws clamp onto this shell structure, thereby reducing testing costs.
[0068] refer to Figure 2 and Figure 3 As shown in some embodiments of this application, at least one tension band 4 is provided, and the tension band 4 is symmetrically arranged along the length direction of the battery.
[0069] Based on the embodiments described above, one or more tension bands 4 can be provided. When one tension band 4 is provided, it is positioned at the middle of the battery's length direction, thus achieving a symmetrical arrangement along the battery's length direction. When two tension bands 4 are provided, they are symmetrically arranged along the battery's length direction. Similarly, when the number of tension bands 4 continues to increase, the tension bands 4 as a whole still need to be symmetrically arranged along the battery's length direction.
[0070] By symmetrically arranging the tension band 4 along the length of the battery, the tensile force can be evenly transmitted between the top cover 2 and the lower plastic 3 during testing. This also prevents the battery from shifting to one side during measurement, thus avoiding any impact on the accuracy of the test results.
[0071] Furthermore, it should be noted that, in order to ensure the accuracy of the test results, in this application, when multiple tension bands 4 are provided, the ends of the multiple tension bands 4 should converge at the same position, and the grippers of the tension testing machine will simultaneously clamp the ends of the multiple tension bands 4, so that the tension applied by the tension testing machine through the grippers is evenly transmitted to the connecting structure through the multiple tension bands 4.
[0072] In some embodiments of this application, the width of the tension band 4 is set to 10mm-50mm.
[0073] Based on the above embodiments of this application, the width of the tension band 4 is limited to ensure that the tension band 4 has a sufficient load-bearing cross-sectional area, guaranteeing its own strength and enabling it to withstand the tensile force required during the test without tearing or prematurely breaking. This limits the failure location to the connection structure of the battery top cover assembly, thereby ensuring the authenticity and validity of the test data.
[0074] Meanwhile, by limiting the width of the tension band 4, an appropriate width avoids assembly difficulties caused by an excessively wide tension band 4, while also preventing stress concentration in localized areas and premature tearing of the tested structure due to an excessively narrow tension band 4. This width range ensures that the tensile force can be applied evenly and centrally to the connection structure between the top cover 2 and the lower plastic 3, so that the measured tensile strength truly reflects the actual strength of the connection structure.
[0075] Specifically, in actual production and processing, the width of the tension band 4 can be set to multiple specific widths such as 10mm, 20mm, 30mm, 40mm, and 50mm, which can be selected according to the battery size and the number of tension bands 4. For example, when the battery size is fixed, if there is one tension band 4, a tension band 4 with a width of 50mm can be set at the middle position along the length of the battery. When there are two tension bands 4, the width of the tension band 4 can be set to 30mm. The specific setting can be determined according to the actual situation, and this application does not impose specific restrictions on it.
[0076] In some embodiments of this application, the lower plastic 3 is symmetrically arranged along the length of the battery, and the cell insulating sheet 1 is correspondingly arranged with the lower plastic 3. The cell insulating sheet 1 is fixed to the lower plastic 3 by hot melt welding, and the lower plastic 3 is fixed to the top cover 2 by any one of the following methods: snap fastener, ultrasonic welding, or interference fit.
[0077] Based on the embodiments described above, by symmetrically arranging the lower plastic 3 along the length of the battery and correspondingly arranging the cell insulating sheet 1 with the lower plastic 3, the stress distribution of the entire test structure is ensured to have geometric symmetry. During the tensile process, the tensile force can be evenly transmitted to each connection point, avoiding stress concentration caused by connection position offset, thus making the measurement results more accurate and reliable.
[0078] Meanwhile, the connection method between the cell insulation sheet 1 and the lower plastic 3, as well as the connection method between the lower plastic 3 and the top cover 2, are consistent with the connection methods of the above-mentioned components in the actual battery assembly, so as to more accurately simulate the stress of the above-mentioned components in actual working conditions and further improve the accuracy of the test.
[0079] In some embodiments of this application, the breaking force of the tension band 4 is greater than the breaking force of the battery core insulating sheet 1 and the breaking force of the lower plastic 3.
[0080] Based on the embodiments described above, when the above structures are specifically connected, the cell insulating sheet 1 and the lower plastic sheet 3 serve as the connection structure between the top cover 2 and the battery. Therefore, in the event of failure, the failure location is usually at the connection point of the above components or on the cell insulating sheet 1 and the lower plastic sheet 3. By limiting the tensile strength of the tension band 4 to be higher than that of the cell insulating sheet 1 and the lower plastic sheet 3, it is ensured that the tension band 4 will not break before the cell insulating sheet 1 and the lower plastic sheet 3 during the test. This ensures that the measured failure location and critical strength are the strength of the weak point of the connection structure formed by the top cover assembly and the battery, thereby ensuring the reliability of the measurement results.
[0081] Specifically, in actual production and processing, the breaking force of the tension band 4 is usually required to be more than twice that of the breaking force of the battery cell insulation sheet 1 and the lower plastic 3. This requirement can be achieved by increasing the cross-sectional area of the tension band 4, etc., and this application does not impose specific limitations on this.
[0082] Furthermore, in some embodiments, the tension band 4 and the battery cell insulation sheet 1 are made of the same material.
[0083] Based on the above embodiments of this application, the tension band 4 and the battery cell insulation sheet 1 are made of the same material. In the specific production and preparation process, they can be directly prepared together with the battery cell insulation sheet 1 using the same process, thereby reducing production and processing costs and improving production and processing efficiency.
[0084] In some embodiments of this application, the tensile testing machine is equipped with two grippers, namely an upper gripper 5 and a lower gripper 6. The upper gripper 5 is located directly above the lower gripper 6. The battery cell insulation sheet 1 is clamped in the upper gripper 5, and the end of the tension band 4 is clamped in the lower gripper 6.
[0085] Based on the embodiments described above, by clamping the battery cell insulation sheet 1 to the upper jaw 5 and the end of the tension band 4 to the lower jaw 6, the battery cell insulation sheet 1 is positioned above the tension band 4 during clamping, and its own weight acts on the upper jaw 5. Conversely, if the battery cell insulation sheet 1 is positioned below the tension band 4, its own weight will act on the connection structure, thus affecting the accuracy of the test results. Therefore, through the above-described configuration of this application, the influence of the battery cell insulation sheet 1's own weight on the test can be reduced, thereby improving the test accuracy.
[0086] In some embodiments of this application, the upper jaw 5 clamps the battery near the lower plastic 3.
[0087] Based on the above embodiments of this application, by clamping the upper jaw 5 at the position of the battery near the lower plastic 3, that is, near the weld mark where the cell insulation sheet 1 and the lower plastic 3 are hot-melted, the tensile force during testing can be more concentrated at the connection position between the parts rather than on the battery.
[0088] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.
[0089] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.
[0090] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.
Claims
1. A method for testing the tensile strength of a battery top cover assembly, characterized in that, The tensile testing method includes: A tension band is fitted over the assembly gap between the top cover and the lower plastic, wherein the lower plastic in the battery top cover assembly is fixed to the top cover and the lower plastic is fixed to the cell insulation sheet; The tension testing machine is used to clamp the battery cell insulation sheet and the tension band respectively; Control the tensile testing machine to perform a tensile test between the lower plastic and the top cover.
2. The tensile testing method for the battery top cover assembly according to claim 1, characterized in that, In the tensile test, the tensile testing machine stretches the battery top cover assembly along a first direction until tensile failure occurs, and at the same time records the tensile displacement curve of the tensile testing machine and the failure location of the battery top cover assembly, wherein the first direction is the height direction of the battery.
3. The tensile testing method for the battery top cover assembly according to claim 2, characterized in that, In the tensile test, the first peak of the tensile displacement curve is the critical strength of the connection structure of the battery top cover assembly, thereby determining the critical strength and failure location of the battery top cover assembly.
4. The tensile testing method for the battery top cover assembly according to claim 1, characterized in that, In the tensile test, the stretching rate is 10 mm / min-100 mm / min.
5. A tensile testing structure for a battery top cover assembly, applicable to the tensile testing method for the battery top cover assembly as described in any one of claims 1-4, characterized in that, The tensile test structure includes: Battery cell insulation sheet; A top cover and a lower plastic sheet, wherein the lower plastic sheet is fixed to the top cover, the top cover is disposed at the end of the battery, and the lower plastic sheet is connected to the cell insulation sheet; A tension band is inserted between the top cover and the lower plastic, with both ends of the tension band converging in a direction away from the battery; The tensile testing machine clamps the battery cell insulation sheet and the end of the tensile tape respectively.
6. The tensile testing structure for the battery top cover assembly according to claim 5, characterized in that, The tension band is provided at least one, and the tension band is symmetrically arranged along the length direction of the battery.
7. The tensile testing structure for the battery top cover assembly according to claim 5, characterized in that, The width of the tension band is set to 10mm-50mm.
8. The tensile testing structure for the battery top cover assembly according to claim 6, characterized in that, The lower plastic is symmetrically arranged along the length of the battery, and the cell insulating sheet is arranged correspondingly to the lower plastic. The battery cell insulation sheet is fixed to the lower plastic by hot melt welding, and the lower plastic is fixed to the top cover by any one of the following methods: snap fastener, ultrasonic welding, or interference fit.
9. The tensile testing structure for the battery top cover assembly according to claim 5, characterized in that, The tensile strength of the tension band is greater than the tensile strength of the battery cell insulation sheet and the tensile strength of the lower plastic.
10. The tensile testing structure for the battery top cover assembly according to claim 5, characterized in that, The tension band and the battery cell insulation sheet are made of the same material.