Method for preventing tearing of an electrode tab of a battery cell and battery

Abstract

This invention discloses a method for preventing tearing of battery cell tabs and a battery, relating to the field of battery cell tab tearing technology. It includes: determining the location of pre-welding points; pre-welding and butterfly welding fixing of corresponding tabs of two battery cells; determining the specifications of the welding tape; and applying and protecting the welding areas of the two battery cell tabs based on the welding tape; wherein the middle adhesive area of ​​the welding tape covers the butterfly welding area of ​​the tabs. This invention effectively prevents the concentration of cyclic expansion stress of the battery cell at weak welding points by reducing the width of the middle adhesive area of ​​the cover plate welding tape to not cover the pre-welding points, and suppresses tab arching by moving the pre-welding point location of the tabs inward towards the battery cell. By combining these two methods, the battery cell tab tearing defect rate, after dual optimization, is reduced from 5.5% to 0.06%, greatly improving the reliability of the battery cells.

Description

Technical Field

[0001] This invention relates to the field of cell tab anti-tear technology, and in particular to a cell tab anti-tear fixing method and a battery. Background Technology

[0002] In current lithium-ion battery manufacturing technology, the volume expansion and contraction of the cell during cycling due to lithium insertion and extraction subject its internal structure to periodic stress. If this stress is not effectively released, it can easily cause fatigue damage or even tearing of the tabs, seriously affecting the battery's cycle life and safety performance.

[0003] The existing technology has the following two key drawbacks:

[0004] First, the traditional cover plate welding tape design leads to an unreasonable stress transmission path, causing pre-weld point tearing: Currently, the commonly used U-shaped cover plate welding tape is usually designed with an excessively wide adhesive area, directly covering the electrode tab pre-weld point (a relatively weak initial weld point). This large-area adhesive design, during the cell's cyclic expansion, collects and concentrates the expansion stress borne by the tape, transferring it to the lower, weaker pre-weld point area, creating significant stress concentration. The edge of the pre-weld point thus becomes a high-risk area for tearing failure.

[0005] Secondly, improper design of the pre-welding point position of the tab leads to tab arching and subsequent tearing of the first layer: In the current production process, the pre-welding point of the tab is too far from the core of the battery cell. This distance causes the tab to easily form an excessive arched structure after welding. During battery cycling, this arched part (especially the outermost first-layer tab) is bound and stretched by the cover plate welding tape attached above, and subjected to repeated bending and tensile stresses. As a result, the stress is highly concentrated at the edge junction of the first-layer tab and the main weld mark, eventually causing the first-layer tab to tear along the edge line of the main weld mark.

[0006] For example, invention application No. 202510199722.2 discloses a method for preventing tearing of electrode tabs, an electrode tab, an electrode assembly, and a battery. The method for preventing tearing of electrode tabs includes applying adhesive material to the welded portion of the electrode tab to form a buffer that at least partially covers the electrode tab. By applying adhesive material to the welded portion of the electrode tab where tearing is likely to occur to form a buffer, and the buffer at least partially covers the welded portion, the electrode tab is prevented from tearing at the welded portion, thus reducing the defect rate of electrode tab tearing. However, this solution has the following drawbacks: this solution only provides buffering and reinforcement to the welded portion of the electrode tab itself, and does not solve the root problems of stress concentration transmission of the tape and the arching and pulling of the electrode tab.

[0007] In summary, how to effectively improve the transmission path of cyclic expansion stress in the battery cell and suppress localized high stress caused by tab arching, while ensuring a reliable connection between the tab and the cover plate, has become a core technical challenge that urgently needs to be solved in this field. This invention aims to provide an innovative solution to the above problems. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to provide a cell tab anti-tear fixing method and battery, solving the problem that the prior art cannot simultaneously ensure the reliability of the tab connection and the tear resistance performance. By adjusting the position of the tab pre-welding point and the coverage area of ​​the intermediate adhesive zone, the stress transmission path of the cell expansion is optimized, and the stress is dispersed to a larger area, avoiding stress concentration at the tab welding point. At the same time, it can restrain the tab from arching deformation, reducing the risk of tab tearing from the root, and will not negatively affect the reliability of the welding connection between the tab and the cover plate.

[0009] The objective of this invention can be achieved through the following technical solution: a method for fixing battery cell tabs against tearing, comprising:

[0010] Determine the location of the pre-welding points, and perform pre-welding and butterfly welding to fix the corresponding tabs of the two cells;

[0011] Determine the specifications of the welding tape, and then use the welding tape to protect the welding area of ​​the two battery cell tabs.

[0012] The adhesive zone in the middle of the welding tape covers the area between the pre-welded points of the two battery cells.

[0013] The above solution, by placing the middle viscous zone of the welding tape between the two pre-welding points, can effectively protect the welding area and use the adhesiveness of the welding tape to constrain the arching deformation of the tabs during cell expansion. This allows the stress generated by cell expansion to be dispersed along the welding tape over a wider area, rather than being concentrated at the butterfly weld position. This effectively improves the tear resistance of the tabs, reduces the risk of tearing and breaking of the tabs during long-term cycling, and extends the battery's lifespan and safety stability.

[0014] As a further embodiment of the present invention, the position of the pre-soldering point is determined by the height of the battery cell tab.

[0015] As a further embodiment of the present invention, the center distance of the solder mark of the pre-welded point from the core is 9±2mm.

[0016] As a further embodiment of the present invention, the width of the middle adhesive zone of the welding tape is determined by the distance between the pre-welding points of the two cells, and the middle adhesive zone of the welding tape covers the electrode butterfly welding area.

[0017] The above solution determines the location of the pre-soldering point and flexibly adapts it to the actual size of the battery cell. While constraining the deformation of the electrode tab, it avoids additional stress concentration on the electrode tab due to deviations in the pre-soldering point location, ensuring uniform stress distribution on the electrode tab structure. By reducing the width of the adhesive zone in the middle of the solder tape to cover the pre-soldering point, it effectively prevents the concentration of cyclic expansion stress of the battery cell at weak weld points, significantly reducing the electrode tab tearing defect rate.

[0018] As a further embodiment of the present invention, the welding tape further includes an outer adhesive region and a non-adhesive region, wherein:

[0019] The non-adhesive area is located between the outer adhesive area and the middle adhesive area, while the outer adhesive area is attached to the edge of the cell end face.

[0020] As a further embodiment of the present invention, the thickness of the welding tape is 30 micrometers to 120 micrometers;

[0021] As a further embodiment of the present invention, the peel strength of the welding tape from the steel plate at 180° is 50 N / m-450 N / m.

[0022] As a further embodiment of the present invention, the tensile strength of the welding tape is greater than 2200 N / m-8000 N / m.

[0023] The welding tape used above has appropriate adhesion and mechanical strength. It can achieve stable adhesion and fixation to the battery cell through the outer adhesive area, and rely on the non-adhesive area to buffer the expansion stress generated during the battery cell cycle. Furthermore, through the matching thickness, peel strength and tensile strength parameters, it can restrain the displacement and deformation of the tab while continuously bearing the stress generated by the battery cell charge and discharge cycle, and will not cause the tape to break or fall off prematurely, thus further ensuring the long-term stability of the tab against tearing.

[0024] A lithium-ion battery, wherein the battery cell is manufactured using the cell tab anti-tear fixing method described in any one of claims 1 to 8.

[0025] When applied to lithium-ion battery production, the above methods can improve the tear resistance stability of the tabs during the charge and discharge cycles of lithium-ion batteries, prevent the tabs from shifting due to cell expansion, effectively reduce the risk of battery failure during use, and extend the overall cycle life of the battery.

[0026] The beneficial effects of this invention are:

[0027] 1. This invention effectively prevents the concentration of cyclic expansion stress in weak welds at the cell by reducing the width of the adhesive zone in the middle of the cover plate welding tape to cover the pre-welded points, thereby reducing the tab tearing defect rate from 5.5% to 0.5%. Furthermore, by shifting the position of the tab pre-welded points inward along the direction of the original cell, tab arching is suppressed, further reducing the tab tearing defect rate from 5.5% to 0.08%. Through the combination of these two methods, the double-optimized cell tab tearing defect rate is reduced from 5.5% to 0.06%, significantly improving the reliability of the battery cells.

[0028] 2. The composite cover plate welding tape used in this invention precisely reduces the width of the middle viscous zone so that it no longer covers the pre-welding point, and symmetrically widens the non-viscous zones on both sides. This composite structure of viscous and non-viscous zones changes the stress transmission path, effectively dispersing the cyclic stress applied to the pre-welding point, thereby avoiding stress concentration and fundamentally preventing tab tearing caused by fatigue accumulation.

[0029] 3. This invention effectively suppresses excessive arching of the tabs by shifting the pre-welding points inward towards the core side, optimizing the distance from the core from 13±2mm to 9±2mm. This optimization makes the tabs smoother in subsequent processes such as core bonding, reducing bending and tensile stress caused by structural arching. Simulation results show that although the stress of the tabs increases after optimization, it is still far below the material failure threshold, significantly reducing the risk of tearing of the first-layer tabs while ensuring process safety. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 The images show the physical and simulated schematic diagrams of the two adhesive coating structures involved in Comparative Example 1, Example 1, Example 2, and Example 3.

[0032] Figure 2 The diagram shows the physical and simulated pre-welded joints involved in Comparative Example 1, Example 1, Example 2, and Example 3.

[0033] Figure 3 This is a schematic diagram simulating the adhesive coating structure and pre-welding distance for Comparative Example 1, Example 1, Example 2, and Example 3;

[0034] Figure 4 A schematic diagram illustrating the process of stretching the first layer of electrode tabs for applying adhesive.

[0035] Figure 5 A schematic diagram illustrating the stress risk during the core-combining process after the pre-welded solder marks have moved towards the core side;

[0036] Figure 6 This is a schematic diagram of the solder joint model for Example 3;

[0037] Figure 7 This is the simulation condition for Example 3;

[0038] Figure 8 This is a schematic diagram of the actual product after the core is assembled and inserted into the shell in Example 3;

[0039] Figure 9 The simulation results are for the positive electrode core of Comparative Example 1 and Example 3;

[0040] Figure 10 The simulation results are for the positive electrode coating and casing of Comparative Example 1 and Example 3;

[0041] Figure 11 The simulation results are for comparing the negative electrode core of Example 1 and Example 3;

[0042] Figure 12 The simulation results are for the negative electrode coating and casing of Comparative Example 1 and Example 3. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0044] This invention discloses a method for fixing battery cell tabs against tearing, comprising: determining the position of the pre-soldering point based on the height of the battery cell tabs, and pre-soldering and butterfly welding the corresponding tabs of the two battery cells.

[0045] Pre-soldering points are used to pre-weld and fix the corresponding tabs of the two cells. This can prevent the tabs from shifting or misaligning during butterfly welding and ensure the accuracy of the subsequent welding position. After the pre-soldering points are completed, butterfly welding is performed. After butterfly welding is completed, the tab welding area is protected with tape.

[0046] In the existing process, the pre-welding point is too far from the core, which makes the tabs prone to forming an excessively arched structure after welding. This arched part (especially the first tab) is subjected to repeated bending and tensile stress during charge and discharge cycles under the constraint of tape adhesion, which causes the stress to be highly concentrated on the first tab and the edge of the solder mark, eventually causing the first tab to tear along the solder mark line.

[0047] Therefore, the location of the pre-welding point is related to the stress distribution after the electrode tab is welded. In the method of the present invention, the pre-welding point is set closer to the core position. By shortening the distance between the pre-welding point and the core, the arching allowance of the electrode tab after welding is reduced, and the electrode tab is prevented from forming a stress concentration structure under the constraint of the tape. This reduces the risk of the first layer electrode tab tearing along the edge of the weld from the structural source.

[0048] Determine the specifications of the welding tape, such as Figure 1 As shown, the welding tape is U-shaped and divided into two outer tacky zones, two non-tacky zones, and an intermediate tacky zone. The intermediate tacky zone is located between the two non-tacky zones, and the non-tacky zone is located between the outer tacky zone and the intermediate tacky zone.

[0049] Traditional welding tape structures, such as Figure 1 As shown in Comparative Example 1 and Example 2, the solder tape typically covers the pre-soldering point and employs an excessively wide intermediate tack zone design, creating an unreasonable stress transmission path. This directs a large amount of stress generated by the cell's cyclic expansion to the already fragile pre-soldering point, making it a high-risk area for tearing failure. Therefore, the specifications of the solder tape are related to the stress transmission path during cell cycling.

[0050] In the method of this invention, the width of the adhesive zone in the middle of the welding tape is determined by the distance between the pre-welding points of the positive and negative electrodes of the battery cell, and the adhesive zone in the middle of the welding tape only covers the butterfly welding area of ​​the electrode tabs, such as... Figure 1 As shown in Examples 1 and 3, without covering the pre-soldering point area, the viscous area in the middle of the welding tape, together with the location of the pre-soldering point, optimizes the stress distribution inside the cell. This not only ensures the fixed strength of the electrode welding area and meets the positioning requirements of the cell assembly process, but also blocks the transmission of stress to the pre-soldering point area during the cell's cyclic expansion, further reducing the probability of the electrode in the pre-soldering point area tearing failure.

[0051] The method of the present invention reduces the width of the middle adhesive zone, so that the welding tape no longer covers the pre-welding point, avoiding the stress concentration generated by the cyclic expansion of the battery cell to the pre-welding point. At the same time, it retains the adhesive fixing effect of the outer adhesive zones on both sides and the middle adhesive zone, ensuring the bonding stability between the tab and the composite cover plate, and further reducing the risk of tab tearing failure from the stress transmission path.

[0052] Furthermore, the specifications of the welding tape are optimized, with a thickness of 30-120 micrometers. This thickness ensures the bonding strength of the tabs, preventing them from shifting during cell cycling, while also preventing excessive tape thickness from taking up extra space inside the cell and affecting its energy density. This aligns with the current demand for compact structure design in lithium-ion batteries.

[0053] Furthermore, the peel strength of the welding tape on a 180° steel plate is 50 N / m-450 N / m. Such peel strength can ensure the adhesion stability between the tab and the welding tape. When the battery cell undergoes repeated expansion and contraction during charging and discharging cycles, it will not easily delaminate or separate. At the same time, this peel strength range will not restrict the release of the small deformation of the tab due to excessive adhesion force, thus avoiding excessive stress accumulation.

[0054] Furthermore, the tensile strength of the welding tape is 2200 N / m-8000 N / m. This tensile strength ensures that the welding tape itself will not break under the cyclic stress of the battery cell, maintaining the continuous constraint and fixation effect on the tab. At the same time, it will not hinder the appropriate distribution of stress due to excessive strength. Together with the thickness and peel strength range mentioned above, they jointly construct a stress buffer system that adapts to the expansion deformation of the battery cell, further improving the tear resistance reliability of the tab.

[0055] The optimization of the welding tape thickness, peel strength, and tensile strength precisely improves the tear resistance of the tabs without adding unnecessary volume inside the cell, ensuring that the overall energy density of the cell remains unaffected. It is compatible with the existing lithium-ion battery production process and design requirements, and can stably constrain the tabs, preventing them from shifting or tearing due to repeated stress during cell cycling, thereby improving the cycle life and safety of the cell.

[0056] Furthermore, the present invention optimizes the setting of the pre-soldering point position of the electrode tab, specifically: as follows: Figure 2 As shown in Examples 2 and 3, the position of the pre-soldering point of the electrode tab is determined by the height of the electrode tab (the distance between the outer edge of the electrode tab and the core), and the center of the pre-soldering point of the electrode tab is 9±2mm away from the core.

[0057] The pre-welding point is set at 9±2mm. The electrode tab and the connecting piece are adjacent to or completely independent of the pre-welding point. This avoids the area with the greatest stress during the core expansion process. It can not only ensure the welding stability of the electrode tab and the current collector, but also reduce the repeated pulling effect of stress on the pre-welding point during charge and discharge cycles, reducing the risk of electrode tab breakage at the pre-welding point. At the same time, sufficient space is reserved at this position to accommodate the small displacement of the electrode tab as the battery expands. This, combined with the buffering effect of the welding tape, improves the overall tear resistance of the electrode tab.

[0058] Effect verification:

[0059] This invention verifies and illustrates the effectiveness of the cell electrode tab anti-tear fixing method by combining Comparative Example 1 (traditional method, without optimization of the electrode tab pre-soldering point position and the middle adhesive area coverage area), Example 1 (only the middle adhesive area coverage area is adjusted), Example 2 (only the electrode tab pre-soldering point position is adjusted), and Example 3 (both the electrode tab pre-soldering point position and the middle adhesive area coverage area are optimized and adjusted).

[0060] Comparative Example 1:

[0061] like Figure 1 and Figure 3 As shown, the width of the connecting piece is 33.6 mm; the width of the pre-weld stamp is 3 mm; and the width of the butterfly stamp (main weld) is 5 mm.

[0062] The width of the tacky zone in the middle of the welding tape is 34 mm; the width of the non-tacky zone is 13 mm; and the width of the tacky zone at the edge is 5 mm.

[0063] The center of the solder mark of the electrode tab pre-weld point is set at 13mm from the core; the solder mark of the electrode tab and the connecting piece completely covers the solder mark area of ​​the electrode tab pre-weld point.

[0064] Example 1:

[0065] like Figure 1 and Figure 3 As shown, the width of the connecting piece is 33.6 mm; the width of the pre-weld stamp is 3 mm; and the width of the butterfly stamp (main weld) is 5 mm.

[0066] The width of the tacky zone in the middle of the welding tape is 30 mm; the width of the non-tacky zone is 15 mm; and the width of the tacky zone at the edge is 5 mm.

[0067] The center of the solder mark of the electrode tab pre-weld point is set at 13mm from the core; the solder mark of the electrode tab and the connecting piece completely covers the solder mark area of ​​the electrode tab pre-weld point.

[0068] Example 2:

[0069] like Figure 1 and Figure 3 As shown, the width of the connecting piece is 33.6 mm; the width of the pre-weld stamp is 3 mm; and the width of the butterfly stamp (main weld) is 5 mm.

[0070] The width of the tacky zone in the middle of the welding tape is 34 mm; the width of the non-tacky zone is 13 mm; and the width of the tacky zone at the edge is 5 mm.

[0071] The center of the pre-welded point of the electrode tab is set at 9mm from the core, so that the electrode tab and the connecting piece are adjacent to or completely independent of the pre-welded point.

[0072] Example 3:

[0073] like Figure 1 , Figure 3 As shown, the width of the connecting piece is 33.6 mm; the width of the pre-weld stamp is 3 mm; and the width of the butterfly stamp (main weld) is 5 mm.

[0074] The width of the tacky zone in the middle of the welding tape is 30 mm; the width of the non-tacky zone is 15 mm; and the width of the tacky zone at the edge is 5 mm.

[0075] The center of the pre-welded point of the electrode tab is set at 9mm from the core, so that the electrode tab and the connecting piece are adjacent to or completely independent of the pre-welded point.

[0076] Based on the statistical analysis of the tab tearing defect rate of 100 PCS in Comparative Example 1, Example 1, Example 2, and Example 3, the results are shown in Table 1:

[0077] Table 1. Statistics on the Defect Rate of Electrode Tear

[0078]

[0079] As can be seen from Table 1, the battery cell with tab tearing defects synthesized using the method of the present invention (Example 3) has significantly reduced defects, thus increasing the reliability of the battery.

[0080] Below, the adhesive application effect is verified based on Comparative Example 1 and Example 3. Figure 7 This is a schematic diagram of the first layer of tabs being pulled apart for adhesive application. After the product of Example 3 of this invention was immersed in electrolyte for 7 days, it was disassembled. After disassembly, the width of the middle adhesive zone in Example 3 was reduced from 34mm to 30mm, but this did not affect the adhesive application effect after electrolyte injection. The tape did not detach, fall off, or dissolve, and the tabs showed no signs of tearing.

[0081] In Comparative Example 1, the method of narrowing the middle adhesive area was not adopted, and the tab position showed obvious arching deformation. However, the tab after processing in Example 3 of the present invention was flat and there was no arching or offset problem. There were no wrinkles or curling of the welding tape at the tab, and it could be completely and flatly attached to the surface of the tab and the connecting piece, which played a stable covering and reinforcement role for the tab.

[0082] Vibration tests were performed on Example 3 using the method of the present invention:

[0083] After the cell capacity is checked, the AC internal resistance is measured after full charging: charge at 0.2C constant current and constant voltage until 3.65V / 0.05C cutoff, and let stand for 30 minutes;

[0084] The battery cell uses a sinusoidal waveform, with the frequency oscillating between 7Hz and 200Hz and then returning to 7Hz in a logarithmic sweep for 15 minutes. This is repeated 12 times in each of the XYZ directions, for a total of 3 hours. The logarithmic sweep is as follows: starting from 7Hz, maintain a maximum acceleration of 1gn until the sweep reaches 18Hz. Then, maintain the amplitude at 0.8mm (total offset 1.6mm) and increase the frequency until the maximum acceleration reaches 8gn (frequency approximately 50Hz). Maintain the maximum acceleration at 8gn until the frequency increases to 200Hz.

[0085] After the test, observe for 1 hour, then discharge and disassemble to confirm whether there is any electrode tearing near the solder mark. Vibration data of 100 pieces of products are collected, as shown in Table 2:

[0086] Table 2. Vibration data statistics table for Example 3

[0087]

[0088] As can be seen from the data in Table 2, there were no abnormal fluctuations in voltage and internal resistance before and after the test. Subsequent disassembly and observation also revealed no defects such as tearing of the electrode near the solder mark. This indicates that the adhesive fixing process can effectively improve the tear resistance of the battery cell electrode under vibration under the test conditions, and meet the reliability requirements of the battery cell.

[0089] Figure 4 A diagram illustrating the process of stretching the first layer of electrode tabs for applying adhesive. Figure 5 A schematic diagram illustrating the stress risk during the core-joining process after the pre-welded solder marks move towards the core side; combining Comparative Example 1 and Example 3, the core-joining, wrapping, and shell insertion are performed, as follows: Figure 6 , Figure 7 and Figure 8 As shown, the maximum stress on the positive and negative electrodes of the battery cell after core bonding, coating, and casing are statistically analyzed. Specifically:

[0090] The stress on the positive electrode was simulated during core bonding, coating, and casing. The maximum stress on the positive electrode tab is shown in Table 3.

[0091] Table 3. Statistics of Maximum Stress on Positive Electrode Tab

[0092]

[0093] As can be seen from the results in Table 3, after the position of the pre-welded stamp is adjusted, the stress on the positive electrode tab increases after the core is assembled and the film is inserted into the shell, but it does not exceed the failure threshold, and there is no risk of failure of the positive electrode tab.

[0094] Simulation applications such as Figure 9 As shown, the stress comparison of the positive electrode core is as follows: Comparative Example 1: maximum stress 129.509 MPa; Example 3: maximum stress 140.943 MPa; The stress in Example 3 is slightly higher, but far below the failure threshold of 260 MPa.

[0095] Simulation applications such as Figure 10 As shown, the stress comparison of positive electrode coating + casing is as follows: Comparative Example 1: maximum stress 129.345 MPa; Example 3: maximum stress 143.568 MPa; The stress in Example 3 is slightly higher, but still far below 260 MPa, with no risk of failure.

[0096] Simulations were performed on the negative electrode stress of Comparative Example 1 and Example 3. The maximum stress of the negative electrode tab is shown in Table 4.

[0097] Table 4. Statistics of Maximum Stress on Negative Electrode Tabs

[0098]

[0099] As can be seen from the results in Table 4, after the position of the pre-welded stamp is adjusted, the stress on the negative electrode tab increases after the core is assembled and the film is inserted into the shell, but it does not exceed the failure threshold, and there is no risk of failure of the negative electrode tab.

[0100] Simulation applications such as Figure 11 As shown, the stress comparison of the negative electrode core is as follows: Comparative Example 1: maximum stress 209.943 MPa; Example 3: maximum stress 253.309 MPa; The stress in Example 3 is slightly higher, but far below the failure threshold of 340 MPa.

[0101] Simulation applications such as Figure 12 As shown, the stress comparison of negative electrode coating + casing is as follows: Comparative Example 1: maximum stress 230.806 MPa; Example 3: maximum stress 244.004 MPa; The stress in Example 3 is slightly higher, but still far below 340 MPa, with no risk of failure.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for fixing battery cell tabs against tearing, characterized in that, include: Determine the location of the pre-welding points, and perform pre-welding and butterfly welding to fix the corresponding tabs of the two cells; Determine the specifications of the welding tape, and then use the welding tape to protect the welding area of ​​the two battery cell tabs. The adhesive zone in the middle of the welding tape covers the area between the pre-welded points of the two battery cells.

2. The method according to claim 1, characterized in that, The location of the pre-soldering point is determined by the height of the cell tab.

3. The method according to claim 2, characterized in that, The center distance of the weld mark at the pre-welded point is 9±2mm from the core.

4. The method according to claim 1, characterized in that, The width of the middle viscous zone of the welding tape is determined by the distance between the pre-welding points of the two cells, and the middle viscous zone of the welding tape covers the electrode butterfly welding area.

5. The method according to claim 1, characterized in that, The welding tape also includes an outer adhesive area and a non-adhesive area, wherein the non-adhesive area is located between the outer adhesive area and the middle adhesive area, and the outer adhesive area is pasted on the edge of the cell end face.

6. The method according to claim 5, characterized in that, The thickness of the welding tape is 30 micrometers to 120 micrometers.

7. The method according to claim 5, characterized in that, The peel strength of the welding tape from steel plate at 180° is 50 N / m-450 N / m.

8. The method according to claim 5, characterized in that, The tensile strength of the welding tape is greater than 2200N / m-8000N / m.

9. A lithium-ion battery, characterized in that, The battery cell manufacturing process employs the cell tab anti-tear fixing method described in any one of claims 1 to 8.

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