Negative electrode collector plate, battery and battery pack

Abstract

The present invention relates to the field of battery technology, and discloses a negative electrode collector disk, a battery and a battery pack, wherein the negative electrode collector disk includes a first welding area, a second welding area and an elastic buffer area. The first welding area includes a first welding portion, and the first welding portion is suitable for welding with the negative electrode cover plate of the battery; the second welding area is located outside the first welding area, and the second welding area includes a second welding portion, and the second welding portion is suitable for welding with the electrode group of the battery; the second welding portion is recessed in the first welding portion; the elastic buffer area is located between the first welding area and the second welding area, and radially separates the first welding portion and the second welding portion; the inner side of the elastic buffer area is connected to the first welding portion, and the outer side of the elastic buffer area is connected to the second welding portion. The present invention sets an elastic buffer area so that there will be no mutual influence of vibration between the first welding area and the second welding area, thereby ensuring the performance of the battery cell, avoiding pulling on the pole ear due to inaccurate positioning, and having high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a negative electrode current collecting disk, a battery and a battery pack. Background Art

[0002] The cylindrical battery includes a shell, an electrode group, a negative electrode collector and a negative electrode cover, wherein the shell provides a receiving cavity for accommodating the electrode group, the electrode group is used to store and release energy, and the negative electrode collector conducts the energy of the electrode group to the outside.

[0003] Welding is used between the negative electrode collector and the electrode group, as well as between the negative electrode collector and the shell. During the welding process, vibrations will be generated in the welding area. The vibrations will be transmitted and diffused, affecting each other, thereby affecting the performance of the battery cell. Summary of the invention

[0004] In view of this, the present invention provides a negative electrode current collector, a battery and a battery pack to solve the problem that the vibration caused by the welding between the negative electrode current collector and the electrode group, and the welding between the negative electrode current collector and the shell affects the battery performance.

[0005] In a first aspect, the present invention provides a negative electrode current collector, comprising a first welding area, a second welding area and an elastic buffer area. The first welding area comprises a first welding portion, which is suitable for welding with the negative electrode cover of the battery; the second welding area is located outside the first welding area, the second welding area comprises a second welding portion, which is suitable for welding with the electrode group of the battery; the second welding portion is recessed in the first welding portion; the elastic buffer area is located between the first welding area and the second welding area, and radially separates the first welding portion and the second welding portion; the inner side of the elastic buffer area is connected to the first welding portion, and the outer side of the elastic buffer area is connected to the second welding portion.

[0006] Beneficial effects: An elastic buffer is provided between the first welding portion and the second welding portion, and the elastic buffer separates the first welding portion and the second welding portion in the radial direction, that is, in the radial direction, the first welding area and the second welding area do not overlap, so that, on the first hand, when the negative electrode collector plate and the negative electrode cover plate are welded, and when the negative electrode collector plate and the pole group are welded, the first welding area and the second welding area will not affect each other, and the vibration generated by the welding action of one welding area is absorbed in the elastic buffer and will not be transmitted to the other welding area, thereby avoiding affecting the positioning between the structural parts of the other welding area, ensuring the welding effect and the positioning effect, and ensuring the performance of the battery cell. On the second hand, since the existing negative electrode collector plate and the pole group may have processing errors and assembly errors, when welding between the negative electrode collector plate and the pole group, the two are prone to have a matching gap, resulting in a cold weld, which affects the safety and reliability of the product. In the present application, since an elastic buffer is provided, the elastic buffer has elastic deformation capability. After the welding between the negative electrode collector and the negative electrode cover is completed in the first welding area, the welding of the second welding area is carried out. In this process, the structure of the elastic buffer can be deformed by slightly applying pressure to the negative electrode collector to compensate for the fitting gap between the negative electrode collector and the pole group, ensuring the tight fitting welding between the negative electrode collector and the pole group, ensuring the positioning between the negative electrode collector and the pole group, avoiding the generation of cold welding, improving the reliability and safety of the product, and improving the yield of the product. On the third aspect, since an elastic buffer is provided, the positioning between the negative electrode collector and the negative electrode cover and the pole group is guaranteed, avoiding the pulling of the pole ear due to inaccurate positioning when welding between the second welding part and the pole group in the second welding area after the welding between the first welding area and the negative electrode cover is carried out, and the reliability is high.

[0007] In an optional embodiment, the elastic buffer zone includes at least two elastic buffer ribs arranged at intervals along the circumference of the first welding portion, the inner end of the elastic buffer rib is connected to the first welding portion, the outer end of the elastic buffer rib is connected to the second welding portion, and a first through hole is provided between adjacent elastic buffer ribs.

[0008] Beneficial effects: The elastic buffer ribs can prevent the transmission of vibrations generated during welding between the first welding area and the second welding area. At the same time, the elastic buffer ribs have a simple structure and use less materials, which can reduce weight and reduce costs. In addition, because the first through hole is provided between adjacent elastic buffer ribs, the buffering effect of the elastic buffer ribs can be improved, and the vibration transmission during welding between the first welding area and the second welding area can be further weakened. At the same time, the provision of the first through hole can further improve the effect of reducing weight and reducing costs.

[0009] In an optional embodiment, the extension width of the elastic buffer rib along the circumferential direction is 0.8 mm to 2 mm, and the wall thickness of the elastic buffer rib along the axial direction is smaller than the wall thickness of the second welding portion along the axial direction.

[0010] Beneficial effect: With this arrangement, in the event of an external short circuit in the battery, a large current is generated to fuse the elastic buffer ribs and interrupt the circuit transmission path; sufficient elasticity of the product is ensured during the manufacturing process.

[0011] In an optional embodiment, the negative electrode current collecting disk is circular, and the ratio of the radial extension length of the elastic buffer rib to the diameter of the negative electrode current collecting disk is 0.15 to 1.

[0012] Beneficial effect: Such arrangement can ensure that the negative electrode current collector and the negative electrode cover have sufficient welding area to ensure the current capacity and battery performance, and ensure that the elastic buffer rib has sufficient strength to compensate for the eccentricity of the current collector during the manufacturing process.

[0013] In an optional embodiment, along the axial direction, the elastic buffer rib at least partially protrudes and / or is recessed in the first welding portion, and the ratio of the height of the elastic buffer rib protruding and / or recessed in the first welding portion to the wall thickness of the second welding portion is 0.8 to 1.5.

[0014] Beneficial effect: This arrangement can not only ensure the strength of the elastic buffer ribs but also save the internal space of the battery and improve space utilization.

[0015] In an optional embodiment, the elastic buffer ribs are bent along the circumference toward the same rotation direction.

[0016] Beneficial effect: This arrangement enables the elastic buffer ribs to deform in the same rotation direction after being stressed, reducing the mutual cancellation of forces between adjacent elastic buffer ribs when deformed under stress, thereby ensuring the buffering effect on welding vibration.

[0017] In an optional embodiment, the inner side of the first through hole extends to the first welding area, and the outer side of the first through hole extends to the second welding area.

[0018] Beneficial effect: This arrangement can resist the transmission of welding vibration to the greatest extent.

[0019] In an optional embodiment, the negative electrode current collecting disk further includes a wetting hole for electrolyte infiltration.

[0020] Beneficial effect: By setting the wetting hole in the first welding area, the electrolyte can infiltrate from the wetting hole toward the electrode group, thereby improving the wetting effect of the electrolyte.

[0021] In an optional embodiment, the thickness of the first welding portion along the axial direction is 0.1 mm to 0.6 mm.

[0022] Beneficial effects: This setting can not only ensure the stability and reliability of welding quality, but also save costs and improve product competitiveness.

[0023] In a second aspect, the present invention further provides a battery, comprising a housing, an electrode group, a negative electrode cover plate, and a negative electrode collector plate according to any one of the above technical solutions. The housing comprises a receiving cavity having an opening; the electrode group is arranged in the receiving cavity of the housing; the negative electrode cover plate is arranged in the opening of the housing; the first welding portion is welded to the negative electrode cover plate, and the second welding portion is welded to the electrode group.

[0024] Beneficial effect: Since the battery includes the negative electrode current collecting disk described in the above technical solution, it has the same effect as the negative electrode current collecting disk, which will not be described in detail here.

[0025] In a third aspect, the present invention further provides a battery pack, comprising the battery in the above technical solution.

[0026] Beneficial effect: Since the battery pack includes the battery described in the above technical solution, it has the same effect as the battery and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 is a three-dimensional diagram of a first negative electrode current collector according to an embodiment of the present invention;

[0029] Figure 2 is a three-dimensional diagram of a second negative electrode current collector according to an embodiment of the present invention;

[0030] Figure 3 for Figure 2 A top view of the negative electrode current collector shown;

[0031] Figure 4 For along Figure 3 Sectional view at AA in the middle;

[0032] Figure 5 is a three-dimensional diagram of a third negative electrode current collector according to an embodiment of the present invention;

[0033] Figure 6 is a three-dimensional diagram of a fourth negative electrode current collector according to an embodiment of the present invention;

[0034] Figure 7 is a three-dimensional diagram of a battery according to an embodiment of the present invention;

[0035] Figure 8 for Figure 7 A top view of the battery shown;

[0036] Fig. 9 For along Figure 8 Sectional view at the middle BB;

[0037] Fig.10 for Fig. 9 A partial enlarged view of point C in the middle.

[0038] Description of reference numerals:

[0039] 1. First welding area; 101. First welding part; 102. Groove; 2. Second welding area; 201. Second welding part; 3. Elastic buffer; 301. Elastic buffer rib; 302. First through hole; 4. Wetting hole; 401. Second through hole; 402. Third through hole; 10. Negative electrode current collector; 20. Electrode group; 30. Shell; 40. Negative electrode cover; 100. Battery. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0041] Combine the following Figures 1 to 10 , describing an embodiment of the present invention.

[0042] According to an embodiment of the present invention, in a first aspect, a negative electrode current collector 10 is provided, comprising a first welding area 1, a second welding area 2 and an elastic buffer area 3. The first welding area 1 comprises a first welding portion 101, which is suitable for welding with the negative electrode cover plate 40 of the battery 100; the second welding area 2 is located outside the first welding area 1, and the second welding area 2 comprises a second welding portion 201, which is suitable for welding with the electrode group 20 of the battery 100; the second welding portion 201 is recessed in the first welding portion 101; the elastic buffer area 3 is located between the first welding area 1 and the second welding area 2, and radially separates the first welding portion 101 and the second welding portion 201; the inner side of the elastic buffer area 3 is connected to the first welding portion 101, and the outer side of the elastic buffer area 3 is connected to the second welding portion 201.

[0043] By setting the first welding area 1, a first welding portion 101 is set in the first welding area 1, and the negative electrode current collector 10 and the negative electrode cover 40 are welded at the first welding portion 101. By setting the second welding area 2, a second welding portion 201 is set in the second welding area 2, and the negative electrode current collector 10 and the electrode group 20 are welded at the second welding portion 201. The first welding area 1 is arranged on the inner side, the second welding area 2 is arranged on the outer side, and an elastic buffer zone 3 is arranged between the first welding part 101 and the second welding part 201, and the elastic buffer zone 3 separates the first welding part 101 and the second welding part 201 in the radial direction, that is, in the radial direction, the first welding area 1 and the second welding area 2 do not overlap, so that, on the first hand, when the negative electrode collector 10 and the negative electrode cover plate 40 are welded, and when the negative electrode collector 10 and the pole group 20 are welded, the first welding area 1 and the second welding area 2 will not affect each other, and the vibration generated by the welding action of one welding area is absorbed in the elastic buffer zone 3 and will not be transmitted to the other welding area, thereby avoiding affecting the positioning between the structural parts of the other welding area, and ensuring the welding effect and the positioning effect. On the second hand, since the existing negative electrode collector 10 and the pole group 20 may have processing errors and assembly errors, when the negative electrode collector 10 and the pole group 20 are welded, the two are prone to have a matching gap, resulting in a cold weld, which affects the safety and reliability of the product.

[0044] In the present application, since an elastic buffer zone 3 is provided, the elastic buffer zone 3 has elastic deformation capability. After the welding between the negative electrode collector plate 10 and the negative electrode cover plate 40 is completed in the first welding zone 1, the welding of the second welding zone 2 is performed. In this process, the structure of the elastic buffer zone 3 can be deformed by slightly applying pressure to the negative electrode collector plate 10 to compensate for the matching gap between the negative electrode collector plate 10 and the electrode group 20, and ensure the tight fitting welding between the negative electrode collector plate 10 and the electrode group 20, ensure the positioning between the negative electrode collector plate 10 and the electrode group 20, avoid the generation of cold welding, improve the reliability and safety of the product, and improve the yield of the product. On the third aspect, since an elastic buffer zone 3 is provided, the positioning between the negative electrode collector plate 10 and the negative electrode cover plate 40 and the electrode group 20 is ensured, and after the first welding zone 1 and the negative electrode cover plate 40 are welded, when the second welding portion 201 and the electrode group 20 are welded in the second welding zone 2, it is avoided that the pole ear is pulled due to inaccurate positioning, and the reliability is high.

[0045] Specifically, the above-mentioned “the second welding portion 201 is recessed in the first welding portion 101” is based on Figure 1 or Figure 7 In terms of the orientation shown, that is, when the negative electrode current collecting disc 10 provided in this embodiment is assembled with the shell 30 , the negative electrode is on top and the positive electrode is on the bottom, and the second welding portion 201 is recessed in the first welding portion 101 .

[0046] In one embodiment, the elastic buffer zone 3 includes at least two elastic buffer ribs 301 arranged at intervals along the circumference of the first welding portion 101, the inner end of the elastic buffer rib 301 is connected to the first welding portion 101, the outer end of the elastic buffer rib 301 is connected to the second welding portion 201, and a first through hole 302 is provided between adjacent elastic buffer ribs 301.

[0047] It should be noted that the inner end of the elastic buffer rib 301 refers to the end close to the center. Since the first welding area 1 is located on the inner side and the second welding area 2 is arranged on the outer side of the first welding area 1, it can also be considered that the inner end of the elastic buffer rib 301 is close to the first welding area 1. Conversely, the outer end of the elastic buffer rib 301 refers to the end away from the center, that is, the end away from the first welding area 1.

[0048] Since the elastic buffer 3 is provided with elastic buffer ribs 301, the elastic buffer ribs 301 can prevent the transmission of vibrations generated during welding between the first welding zone 1 and the second welding zone 2. At the same time, the elastic buffer ribs 301 have a simple structure and use less materials, which can achieve the effect of reducing weight and reducing costs. In addition, since the first through holes 302 are provided between adjacent elastic buffer ribs 301, the buffering effect of the elastic buffer ribs 301 can be improved, and the transmission of vibrations during welding between the first welding zone 1 and the second welding zone 2 can be further weakened. At the same time, the provision of the first through holes 302 can further improve the effect of reducing weight and reducing costs.

[0049] In one embodiment, the extension width of the elastic buffer rib 301 along the circumferential direction is 0.8 mm to 2 mm, and the wall thickness of the elastic buffer rib 301 along the axial direction is smaller than the wall thickness of the second welding portion 201 along the axial direction.

[0050] The extension width of the elastic buffer rib 301 along the circumferential direction is as follows: Figure 3 As shown in W, if W is less than 0.8, the elastic buffer rib 301 will melt during fast charging and cannot work normally. If W is greater than 2, the battery 100 may cause thermal runaway and other risks when it is abnormal, and the elasticity is insufficient. Therefore, it is controlled to 0.8mm to 2mm. In the case of an external short circuit of the battery 100, a large current is generated to melt the elastic buffer rib 301 and interrupt the circuit transmission path; the product is ensured to have sufficient elasticity during the process.

[0051] In one embodiment, the negative electrode current collecting disc 10 is circular, and the ratio of the radial extension length of the elastic buffer rib 301 to the diameter of the negative electrode current collecting disc 10 is 0.15 to 1.

[0052] The radial extension length of the elastic buffer rib 301 is as follows: Figure 3 As shown in L. The diameter of the negative electrode current collecting disk 10 is D, as shown in Figure 2 As shown in D.

[0053] This arrangement can ensure that the negative electrode current collecting disc 10 and the negative electrode cover plate 40 have sufficient welding area to ensure the current flow capacity and the performance of the battery 100, and ensure that the elastic buffer rib 301 has sufficient strength to compensate for the eccentricity of the current collecting disc during the manufacturing process.

[0054] The elastic buffer rib 301 is set to the above structure. When the current reaches 2500A, it will be fused in about 2 to 3 seconds; when the current reaches 1000A, it will be fused in about 300 seconds; when the current reaches 600 to 800A, it will be fused in about 600 seconds. The elastic buffer rib 301 is set to be able to be fused under severe conditions such as overcharge and overdischarge, so that the internal circuit of the battery 100 is broken, preventing the spread of thermal runaway, and protecting the battery 100 from the risk of explosion and the like.

[0055] In one embodiment, along the axial direction, the elastic buffer rib 301 at least partially protrudes and / or is recessed in the first welding portion 101, and the ratio of the height H2 of the elastic buffer rib 301 protruding and / or recessed in the first welding portion 101 to the wall thickness of the second welding portion 201 is 0.8 to 1.5.

[0056] The elastic buffer rib 301 protrudes and / or recesses the first welding portion 101 by a height H2, such as Figure 5 shown.

[0057] Specifically, the elastic buffer rib 301 and the first welding portion 101 and the second welding portion 201 are not in the same plane. In the axial direction, the elastic buffer rib 301 can be higher than the first welding portion 101 or lower than the first welding portion 101. It can be ensured that after the first welding portion 101 of the negative electrode collector 10 and the negative electrode cover plate 40 are welded, the second welding portion 201 has the ability to move in the radial direction, effectively alleviating the pulling force on the tab caused by the incomplete axial symmetry of the negative electrode collector 10 and the electrode group 20 after the tab is welded, thereby improving the performance of the battery 100. In addition, the ratio of the height H2 of the elastic buffer rib 301 protruding and / or recessed from the first welding portion 101 to the wall thickness of the second welding portion 201 is controlled to be 0.8 to 1.5, which can not only ensure the strength of the elastic buffer rib 301 but also save the internal space of the battery 100 and improve the space utilization rate.

[0058] In one embodiment, the elastic buffer ribs 301 are bent along the circumference toward the same rotation direction.

[0059] This arrangement allows the elastic buffer ribs 301 to deform in the same rotation direction after being stressed, thereby reducing the mutual cancellation of forces between adjacent elastic buffer ribs 301 when deformed under stress, thereby ensuring the buffering effect on welding vibration.

[0060] Specifically, the elastic buffer rib 301 may be bent clockwise around the first welding portion 101 , or may be bent counterclockwise around the first welding portion 101 .

[0061] In one embodiment, the elastic buffer rib 301 has a U-shape, a V-shape or a W-shape.

[0062] The elastic buffer rib 301 can be set to the above three forms. Of course, the elastic buffer rib 301 can also be set to other shapes, such as a "Z" shape, according to actual needs.

[0063] In one embodiment, the inner side of the first through hole 302 extends to the first welding area 1 , and the outer side of the first through hole 302 extends to the second welding area 2 .

[0064] This arrangement can resist the transmission of welding vibration to the greatest extent.

[0065] In one embodiment, the negative electrode current collecting disk 10 further includes a wetting hole 4 for electrolyte infiltration.

[0066] Specifically, the negative electrode current collecting disk 10 is located above the electrode group 20. By providing the infiltration holes 4, the electrolyte can infiltrate from the infiltration holes 4 toward the electrode group 20, thereby improving the infiltration effect of the electrolyte.

[0067] In one embodiment, the thickness of the second welding portion along the axial direction is 0.1 mm to 0.6 mm.

[0068] The thickness of the second welding portion 201 along the axial direction is as follows: Figure 4 As shown in H1.

[0069] If the thickness of the second welding portion 201 along the axial direction is less than 0.1 mm, the laser may damage the tab during welding. If the thickness of the second welding portion 201 along the axial direction is greater than 0.6 mm, the laser welding energy is high, defects such as welding pores are prone to occur, and the cost is high. Therefore, the thickness of the second welding portion 201 along the axial direction is controlled to 0.1 mm to 0.6 mm, which can not only ensure the stability and reliability of welding quality, but also save costs and improve product competitiveness.

[0070] In one embodiment, the wetting hole 4 includes a second through hole 401 disposed in the first welding area 1 and a third through hole 402 disposed in the second welding area 2 .

[0071] In one embodiment, a groove 102 is disposed at the center of the first welding portion 101 .

[0072] By arranging the groove 102 at the center of the first welding area 1 , the structure of the first welding area 1 is not in the same plane, which is beneficial to improving the structural strength of the first welding area 1 .

[0073] Further, when the wetting hole 4 is provided with the second through hole 401 , the second through hole 401 is located in the groove 102 .

[0074] In one embodiment, the wetting hole 4 further includes a plurality of third through holes 402 , and the third through holes 402 are arranged at intervals in the circumferential direction around the second through hole 401 .

[0075] In one embodiment, the third through hole 402 is a long hole, the length direction of the third through hole 402 is arranged radially, and a plurality of third through holes 402 are arranged radially around the second through hole 401 .

[0076] Such an arrangement is conducive to uniform infiltration of the electrolyte and improves the infiltration effect of the electrolyte.

[0077] In one embodiment, the first welding area 1 is circular, and the second welding area 2 is annular.

[0078] Such an arrangement can improve the compatibility between the negative electrode current collecting disk 10 and the cylindrical battery 100 .

[0079] According to an embodiment of the present invention, in a second aspect, a battery is further provided, comprising a housing, an electrode group, a negative electrode cover plate, and a negative electrode current collector according to any one of the above technical solutions. The housing comprises a receiving cavity having an opening; the electrode group is arranged in the receiving cavity of the housing; the negative electrode cover plate is arranged in the opening of the housing; the first welding portion is welded to the negative electrode cover plate, and the second welding portion is welded to the electrode group.

[0080] Because the battery includes the negative electrode current collecting disk described in the above technical solution, it has the same effect as the negative electrode current collecting disk, and will not be described in detail here.

[0081] According to an embodiment of the present invention, in a third aspect, a battery pack is further provided, comprising the battery in the above technical solution.

[0082] Because the battery pack includes the battery described in the above technical solution, it has the same effect as the battery and will not be described in detail here.

[0083] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A negative electrode current collector, characterized in that: include: A first welding area, the first welding area comprising a first welding portion, the first welding portion being suitable for welding with a negative electrode cover plate of a battery; a second welding area, the second welding area being located outside the first welding area, the second welding area comprising a second welding portion, the second welding portion being suitable for welding with a pole group of a battery; the second welding portion being recessed in the first welding portion; an elastic buffer zone, the elastic buffer zone being located between the first welding zone and the second welding zone, separating the first welding portion and the second welding portion in the radial direction, wherein the first welding zone, the elastic buffer zone and the second welding zone do not overlap in the radial direction; the inner side of the elastic buffer zone is connected to the first welding portion, and the outer side of the elastic buffer zone is connected to the second welding portion; The elastic buffer zone comprises at least two elastic buffer ribs arranged at intervals along the circumference of the first welding portion, the inner ends of the elastic buffer ribs are connected to the first welding portion, the outer ends of the elastic buffer ribs are connected to the second welding portion, and a first through hole is provided between adjacent elastic buffer ribs; The elastic buffer ribs are bent along the circumferential direction toward the same rotation direction; The extension width of the elastic buffer rib along the circumferential direction is 0.8 mm to 2 mm, and the wall thickness of the elastic buffer rib along the axial direction is smaller than the wall thickness of the second welding portion along the axial direction; The negative electrode current collector is circular, and the ratio of the radial extension length of the elastic buffer rib to the diameter of the negative electrode current collector is 0.15 to 1; The thickness of the first welding portion along the axial direction is 0.1 mm to 0.6 mm.

2. The negative electrode current collector according to claim 1, characterized in that: Along the axial direction, the elastic buffer rib at least partially protrudes and / or is recessed in the first welding portion, and the ratio of the height of the elastic buffer rib protruding and / or recessed in the first welding portion to the wall thickness of the second welding portion is 0.8 to 1.

5.

3. The negative electrode current collector according to claim 1, characterized in that: The negative electrode current collecting disk further includes a wetting hole for electrolyte infiltration.

4. A battery, characterized in that: include: A housing, the housing comprising a receiving cavity having an opening; A pole group, the pole group is arranged in the accommodating cavity of the shell; A negative electrode cover plate, the negative electrode cover plate being arranged at the opening of the shell; The negative electrode current collector according to any one of claims 1 to 3, wherein the first welding portion is welded to the negative electrode cover plate, and the second welding portion is welded to the electrode group.

5. A battery pack, characterized in that: A battery comprising the battery as claimed in claim 4.

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