Tab, battery and power device

Abstract

The present application relates to the technical field of batteries, and discloses a tab, a battery and a power device. The tab is located on an electrode assembly, and the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a diaphragm. The tab comprises N foils which are stacked, wherein 20≤N≤200, the N foils are welded into a whole to form M weld marks, and M≥2; a 90° peel test is carried out on an ith foil of the tab, wherein 1≤i≤N, the total area of the M weld marks is S1, the remaining total area of the M weld marks after the 90° peel test is S2, and the following conditions need to be met at the same time: when 1≤i≤5, 80%≤S2 / S1≤100%; when 6≤i≤N-5, 10%≤S2 / S1≤100%; and when N-4≤i≤N, 80%≤S2 / S1≤100%. The present application can effectively improve the yield of tab welding, ensure the subsequent laser welding effect between a tab and a pole, improve the welding quality, and reduce production costs.

Description

Tab, battery and power device

[0001] Cross Reference to Related Applications

[0002] This application claims priority to the Chinese Patent Application No. 202410970867.3, filed on July 19, 2024, and entitled “Tab, battery and power device”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery, in particular to a tab, a battery and a power device. BACKGROUND

[0004] The tab of the battery is usually a stack of multiple foils, which are connected into one body by ultrasonic welding. Then the tab is welded with the pole of the battery by laser welding.

[0005] In actual production process, the ultrasonic welding effect is poor, and there is a gap between the foils, which will affect the laser welding effect between the foils and the pole, resulting in laser welding with burst points, poor welding quality, high rejection rate of tab welding, battery scrap, and high production cost. SUMMARY

[0006] Therefore, the present application provides a tab, a battery and a power device to solve the problem of poor welding quality between the foils of the tab itself.

[0007] In a first aspect, the present application provides a tab, the tab being located on an electrode assembly, the tab comprising N layers of foils stacked, 20≤N≤200, the N layers of foils being connected into one body by welding, and forming M welds along the length direction of the tab, M≥2; the i-th layer of foil of the tab is subjected to a 90° peeling force test, 1≤i≤N, the total area of the M welds is S1, unit: mm 2 , the total area of the M welds after the 90° peeling force test is S2, unit: mm 2 , and the test results need to meet the following conditions:

[0008] In the range of 1≤i≤5, the result of the 90° peeling force test of each layer of foil is: 80%≤S2 / S1≤100%;

[0009] In the range of 6≤i≤N-5, the result of the 90° peeling force test of any layer of foil is: 10%≤S2 / S1≤100%;

[0010] In the range of N-4≤i≤N, the result of the 90° peeling force test of each layer of foil is: 80%≤S2 / S1≤100%.

[0011] Beneficial effects: the tab provided by the present application controls the number of foil layers in three intervals, the first five layers are 1≤i≤5, the last five layers are N-4≤i≤N, and the middle layers are 6≤i≤N-5. In different intervals, the ratio of the total area S2 of the remaining M welds after the 90° peeling force test to the total area S1 of the M welds is controlled within the above range, which can effectively improve the yield of tab welding, ensure the laser welding effect between the subsequent tab and the pole, improve the welding quality, and reduce the production cost.

[0012] In an optional embodiment, the length of the tab is L, in mm, the total length of the M welds is K, in mm, the tab includes a first edge and a second edge at the two ends of the length direction, the minimum distance between the weld near the first edge and the first edge is B, in mm, the minimum distance between the weld near the second edge and the second edge is C, in mm, the M welds are arranged at intervals, the distance between adjacent welds is A, in mm, and satisfies: 4mm≤A≤30mm, wherein A=(L-K-B-C) / (M-1).

[0013] In an optional embodiment, the minimum distance B between the weld near the first edge and the first edge is in the range of: B≥1.5mm.

[0014] In an optional embodiment, the minimum distance C between the weld near the second edge and the second edge is in the range of: C≥1.5mm.

[0015] In an optional embodiment, the length of each weld is D, in mm, then K=M×D.

[0016] In an optional embodiment, there is an overlapping area between adjacent welds, the length of the overlapping area is P, in mm, and satisfies: 2mm≤P≤20mm.

[0017] In an optional embodiment, the total length of the M welds is K, in mm, the length of each weld is D, in mm, and the length of each overlapping area is P, then K=M×D-(M-1)×P.

[0018] In an optional embodiment, the adjacent two edges of the weld are connected by a circular arc with a radius R, and 0.01mm≤R≤10mm.

[0019] In a second aspect, the present application also provides a battery, which includes a shell, an electrode assembly, and the tab of any one of the above technical solutions. The shell is provided with a cover plate assembly, and the shell and / or the cover plate assembly is provided with a pole. The electrode assembly is enclosed in the shell by the cover plate assembly. One end of the tab is in conductive connection with the electrode assembly, and the other end of the tab is in conductive connection with the pole.

[0020] Beneficial effects: because the battery includes the tab, has the same effect with the tab, here is not repeated.

[0021] In a third aspect, the application also provides a power device, comprising the battery in the above technical solution.

[0022] Beneficial effects: because the power device includes the battery, has the same effect with the battery, here is not repeated. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0024] Fig. 1 is a schematic diagram of the cross-sectional structure of a tab of an embodiment of the application;

[0025] Fig. 2 is a schematic diagram of the structure of the welding mark arranged in the interval mode;

[0026] Fig. 3 is a schematic diagram of the structure of the welding mark arranged in the overlapping mode;

[0027] Fig. 4 is a schematic diagram of the remaining welding mark after the 90° peeling force test;

[0028] Fig. 5 is a schematic diagram of various parameters when the welding mark is arranged in the interval mode;

[0029] Fig. 6 is a schematic diagram of various parameters when the welding mark is arranged in the overlapping mode;

[0030] Fig. 7 is a schematic diagram of the structure of the welding mark.

[0031] Explanation of reference signs: 1, tab; 2, electrode assembly; 3, foil; 4, welding mark. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are some embodiments of the application, not all embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0033] The embodiments of the application will be described below in combination with Figs. 1 to 7.

[0034] According to the embodiment of the present application, in one aspect, a tab 1 is provided on an electrode assembly 2, the tab 1 comprising N layers of foils 3 stacked together, 20≤N≤200, the N layers of foils 3 being integrated by welding, and forming M welds 4 along the length direction of the tab 1, M≥2; the i-th layer of foil 3 of the tab 1 is subjected to a 90° peel force test, 1≤i≤N, the total area of the M welds 4 is S1, unit: mm2 2 , the total residual area of the M welds 4 after the 90° peel force test is S2, unit: mm2 2 , and the test results need to meet the following conditions:

[0035] In the range of 1≤i≤5, the result of the 90° peel force test of each layer of foil 3 is: 80%≤S2 / S1≤100%;

[0036] In the range of 6≤i≤N-5, the result of the 90° peel force test of any layer of foil 3 is: 10%≤S2 / S1≤100%;

[0037] In the range of N-4≤i≤N, the result of the 90° peel force test of each layer of foil 3 is: 80%≤S2 / S1≤100%.

[0038] Specifically, the electrode assembly 2 comprises a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet.

[0039] In FIG. 1, the first layer of foil, the second layer of foil, the third layer of foil, the fourth layer of foil, the fifth layer of foil, the sixth layer of foil, …, the N-5th layer of foil, the N-4th layer of foil, the N-3th layer of foil, the N-2th layer of foil, the N-1th layer of foil, and the Nth layer of foil are sequentially arranged along the X direction.

[0040] Specifically, in the range of 1≤i≤5, the 90° peel force test is performed on each layer of foil 3, and the value of S2 / S1 after the 90° peel force test of each layer of foil 3 needs to be in the range of 80% to 100%.

[0041] Similarly, in the range of N-4≤i≤N, the 90° peel force test is performed on each layer of foil 3, and the value of S2 / S1 after the 90° peel force test of each layer of foil 3 needs to be in the range of 80% to 100%.

[0042] In the range of 6≤i≤N-5, S2 / S1 after the 90° peel force test of any layer of foil 3 needs to be in the range of 10% to 100%. Within this range, it can be tested once or multiple times.

[0043] The number of layers of the tab 1 and the foil 3 is controlled within three intervals, the first five layers are 1≤i≤5, the last five layers are N-4≤i≤N, and the middle layers are 6≤i≤N-5. In different intervals, the ratio of the total area S2 of the M welds 4 after the 90° peeling force test to the total area S1 of the M welds 4 is controlled within the above range, which can effectively improve the yield of the tab 1 welding, ensure the laser welding effect between the tab 1 and the pole in the subsequent process, improve the welding quality, and reduce the production cost.

[0044] In some embodiments, the length of the tab 1 is L, the unit is mm, the total length of the M welds 4 is K, the unit is mm, the tab 1 includes a first edge and a second edge at both ends of the length direction, the minimum distance between the weld near the first edge and the first edge is B, the unit is mm, the minimum distance between the weld near the second edge and the second edge is C, the unit is mm, the M welds 4 are arranged at intervals, the distance between adjacent welds 4 is A, the unit is mm, and the following is satisfied: 4mm≤A≤30mm, wherein A=(L-K-B-C) / (M-1).

[0045] By controlling the distance A between adjacent welds 4 within the range of 4mm to 30mm, it can be ensured that the foil 3 will not crack after welding, and at the same time the length of the tab 1 can be controlled within a reasonable range, so as to control the weight of the pole piece, which is beneficial to the process welding.

[0046] It should be noted that the total length K of the M welds 4 refers to the sum of the lengths of the M welds 4 itself, and does not include the gap between adjacent welds 4. In some embodiments, each weld 4 is equal in length, and the length is D, the unit is mm, then K=MxD. When each weld 4 is not equal in length, K is the sum of the lengths of the M welds 4.

[0047] In some embodiments, the minimum distance B between the weld near the first edge of the tab 1 and the first edge of the tab 1 is in the range of: B≥1.5mm.

[0048] Since the shape of the tab 1 is not limited, B is the minimum distance between the weld 4 closest to the first edge of the tab 1 and the first edge of the tab 1 along the length direction of the tab 1. Since there is an error in the stacking process of the pole piece, the edge of each layer of the tab 1 will not be in the same vertical plane, which is referred to as tab layer error. If the weld 4 falls on the tab layer error, the service life of the welding head will be reduced, and in severe cases, the tab 1 will be torn. Therefore, by setting the minimum distance B between the first weld 4 and the first edge of the tab 1, and controlling B within the range of at least 1.5mm, the weld 4 can be prevented from falling on the tab layer error, and the welding service life can be improved.

[0049] In some embodiments, the minimum distance C between the weld near the second edge and the second edge of the tab 1 is in the range of: C≥1.5mm.

[0050] Similarly, since the shape of the tab 1 is not limited, C is the minimum distance between the welding mark 4 closest to the second edge of the tab 1 and the second edge of the tab 1 along the length direction of the tab 1. Similarly, by setting C and controlling C in the range of at least 1.5 mm, it can be ensured that the welding mark 4 avoids the tab misregistration and improves the welding life. The minimum distance B between the first welding mark 4 and the first edge of the tab 1 and the minimum distance C between the last welding mark 4 and the second edge of the tab 1 can be equal or not equal, depending on the specific situation.

[0051] In some embodiments, there is an overlapping area between adjacent welding marks 4, and the length of the overlapping area is P, in mm, which satisfies: 2 mm≤P≤20 mm.

[0052] By controlling the length P of the overlapping area in the range of 2 mm≤P≤20 mm, it can be ensured that the foil 3 in the overlapping area after welding does not crack, and at the same time, it can ensure sufficient available laser welding area, which is beneficial to improve the flow capacity of the welding mark 4.

[0053] In some embodiments, the total length of the M welding marks 4 is K, in mm, the length of each welding mark 4 is D, in mm, and the length of each overlapping area is P, then K=M×D-(M-1)×P.

[0054] The M welding marks 4 are divided into two embodiments of equal length and unequal length. When there is an overlapping area between each two adjacent welding marks 4, and the length of the overlapping area is equal, the total length of the M welding marks 4 can be calculated by K=M×D-(M-1)×P.

[0055] In the design process, the total length L of the tab 1 is determined first, and then the length D of the welding mark 4 and the number M of the welding mark 4 are determined. For multiple welding marks 4, it is finally determined whether the welding marks 4 are arranged overlappingly or spacedly.

[0056] In some embodiments, when the total length L of the tab 1 is less than 100 mm, the scheme of overlapping arrangement between adjacent welding marks 4 is selected. When the total length L of the tab 1 is greater than or equal to 100 mm, according to the actual situation, either the scheme of overlapping arrangement between the welding marks 4 or the scheme of spaced arrangement between adjacent welding marks 4 can be selected.

[0057] In some embodiments, the two adjacent edges of the welding mark 4 are connected by a circular arc with a radius R, and 0.01 mm≤R≤10 mm.

[0058] In this way, the two adjacent edges of the welding mark 4 are smoothly connected, which can prevent tearing of the edge of the welding mark 4 during ultrasonic welding.

[0059] Two groups of implementation cases are provided below, 90° peeling force tests are conducted on the three sections of i with the same loading speed. The test results are shown in Table I and Table II.

[0060] Table I:

[0061] Table II:

[0062] From Table I, it can be seen that:

[0063] For implementation case I, in the range of 1≤i≤5, S2 / S1 is less than 80%, in the range of 6≤i≤55, S2 / S1 is less than 10%, in the range of 56≤i≤60, S2 / S1≤80%, after ultrasonic welding, the intermediate layer tab 1 is detached during the transfer process.

[0064] For implementation case II and implementation case III, in the range of 1≤i≤5, S2 / S1 is less than 80%, in the range of 6≤i≤55, S2 / S1 is less than 10%, in the range of 56≤i≤60, S2 / S1≤80%, the tab 1 and the pole base laser welding appear burst points, with a high failure rate.

[0065] From Table II, it can be seen that:

[0066] For implementation case XI, in the range of 1≤i≤5, S2 / S1 is less than 80%, in the range of 6≤i≤95, S2 / S1 is less than 10%, in the range of 96≤i≤100, S2 / S1≤80%, after ultrasonic welding, the intermediate layer tab 1 is detached during the transfer process.

[0067] For implementation case XII and implementation case XIII, in the range of 1≤i≤5, S2 / S1 is less than 80%, in the range of 6≤i≤95, S2 / S1 is less than 10%, in the range of 96≤i≤100, S2 / S1≤80%, the tab 1 and the pole base laser welding appear burst points, with a high failure rate.

[0068] For the remaining implementation cases in Table I and Table II, the tab and the pole base laser welding do not appear abnormal, with a good rate of more than 99%, meeting the limited range of 90° peeling force test.

[0069] A third group of implementation cases is provided below, which are tested with different weld print 4 spacing A. The test results are shown in Table III.

[0070] Table III:

[0071] From Table III, it can be seen that:

[0072] For the twenty-first embodiment, the distance A between the adjacent welds 4 is 2 mm, which is lower than the lower limit value 4 mm of A. The distance between the two adjacent welds 4 is small, and the foil 3 in the blank area between the welds 4 is cracked after welding.

[0073] For the thirtieth embodiment, the distance A between the adjacent welds 4 is 32 mm, which is higher than the upper limit value 30 mm of A. No cracking occurs after welding, but the distance between the adjacent welds 4 is too large, and the foil 3 between the adjacent welds 4 is bulged, which is easy to cause damage to the tabs 1. Therefore, it is not recommended to use.

[0074] For the twenty-fourth embodiment, C = 1 mm, which is less than the lower limit value 1.5 mm of C. The right tab edge tab is damaged.

[0075] For the twenty-fifth embodiment, B = 1 mm, which is less than the lower limit value 1.5 mm of B. The left tab edge tab is damaged.

[0076] In the remaining embodiments, 4 mm ≤ A ≤ 30 mm, B ≥ 1.5 mm, and C ≥ 1.5 mm are satisfied. No cracking and tab damage occur after welding.

[0077] The following provides a fourth group of embodiments for testing different lengths P of the overlapping area of the welds 4. The test results are shown in Table Four.

[0078] Table Four:

[0079] As can be seen from Table Four:

[0080] For the thirty-fourth embodiment, the length P of the overlapping area between the adjacent welds 4 is 1 mm, which is lower than the lower limit value 2 mm of P. The length of the overlapping area between the two adjacent welds 4 is small, and the foil 3 in the overlapping area is cracked after welding.

[0081] For the forty-third embodiment, the length P of the overlapping area between the adjacent welds 4 is 24 mm, which is higher than the upper limit value 20 mm of P. No cracking occurs after welding, but the length of the overlapping area between the adjacent welds 4 is too large, which reduces the usable laser welding area and is not conducive to improving the overcurrent capacity of the welds 4. Therefore, it is not recommended to use.

[0082] For the remaining embodiments, the length P of the overlapping area between the adjacent welds 4 is in the range of 2 mm to 20 mm, and no cracking occurs after welding.

[0083] According to the embodiments of the present application, the second aspect also provides a battery comprising a shell, an electrode assembly 2 and the tab 1 of any one of the above embodiments, the shell is provided with a cover plate assembly, the shell and / or the cover plate assembly is provided with a pole; the electrode assembly 2 is enclosed in the shell by the cover plate assembly; one end of the tab 1 is electrically connected with the electrode assembly 2, and the other end of the tab 1 is electrically connected with the pole.

[0084] Since the battery comprises the tab 1, it has the same effects as the tab 1, which will not be repeated here.

[0085] According to the embodiments of the present application, the third aspect also provides a power device comprising the battery in the above embodiments.

[0086] Since the power device comprises the battery, it has the same effects as the battery, which will not be repeated here.

[0087] Although the embodiments of the present application are described in conjunction with the accompanying drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A tab, characterized by, The tab is located on an electrode assembly, the tab includes N layers of foil materials arranged in a stack, 20≤N≤200, the N layers of foil materials are integrated by welding, and M welding marks are formed along the length direction of the tab, M≥2; The 90° peel force test is performed on the i-th layer of foil of the tab, 1≤i≤N, the total area of the M welds is S1, in mm 2 , the total remaining area of the M welds after the 90° peel force test is S2, in mm 2 , the test results must simultaneously satisfy the following conditions: In the range of 1≤i≤5, the result of 90° peeling force test of each layer of the foil material is: 80%≤S2 / S1≤100%; In the range of 6≤i≤N-5, the result of 90° peeling force test of any one layer of the foil material is: 10%≤S2 / S1≤100%; In the range of N-4≤i≤N, the result of 90° peeling force test of each layer of the foil material is: 80%≤S2 / S1≤100%.

2. The tab of claim 1, wherein The length of the tab is L, unit: mm, the total length of the M welding marks is K, unit: mm, the tab includes a first edge and a second edge located at both ends of the length direction of the tab, the minimum distance between the welding mark close to the first edge and the first edge is B, unit: mm, the minimum distance between the welding mark close to the second edge and the second edge is C, unit: mm, the M welding marks are arranged at intervals, the pitch between adjacent welding marks is A, unit: mm, and it is satisfied that: 4mm≤A≤30mm, wherein A=(L-K-B-C) / (M-1).

3. The tab of claim 2, wherein, The minimum distance B between the welding mark close to the first edge and the first edge is in the range of: B≥1.5mm.

4. The tab according to claim 2 or 3, characterized in that The minimum distance C between the welding mark close to the second edge and the second edge is in the range of: C≥1.5mm.

5. The tab according to claim 2 or 3, characterized in that The length of each welding mark is D, unit: mm, then K=M×D.

6. The tab of claim 1, wherein There is an overlapping area between adjacent welding marks, the length of the overlapping area is P, unit: mm, and it is satisfied that: 2mm≤P≤20mm.

7. The tab of claim 6, wherein, The total length of the M welding marks is K, unit: mm, the length of each welding mark is D, unit: mm, and the length of each overlapping area is P, then K=M×D-(M-1)×P.

8. The tab of any one of claims 1 to 3, wherein, The adjacent two edges of the welding mark are connected by a circular arc with a radius of R, 0.01mm≤R≤10mm.

9. A battery, characterized by It comprises: A shell provided with a cover plate assembly, the shell and / or the cover plate assembly is provided with a pole; An electrode assembly enclosed in the shell by the cover plate assembly; The tab of any one of claims 1 to 8, one end of the tab is in conductive connection with the electrode assembly, and the other end of the tab is in conductive connection with the pole.

10. A power plant characterized by The battery of claim 9. The battery of claim 9.

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