Current collector, battery and battery pack

Abstract

The invention provides a current collector, a battery and a battery pack, and a pin of the current collector comprises a main body part and an extension part; the extension part is provided with a welding part which is in welded connection with an external component; the extension part is provided with a weak part on one side of the welding part close to the main body part; the extension part is provided with a first end and a second end which are oppositely arranged along a second direction, and the weak part is distributed along a linear track and is connected between the first end and the second end; the weak part comprises a first weak part and a second weak part located on at least one side of the first weak part, and the shear strength of the first weak part is smaller than that of the second weak part. Wherein the first weak part leads the bending process, and the lower shearing strength of the first weak part enables the first weak part to be bent before the bonding wire area in the channeling process, so that the electric connection failure caused by the bending and tearing of the bonding wire is avoided. And the second weak part keeps relatively high shearing strength, so that the bending performance is achieved, enough breaking strength can be provided, and the strength stability of the bending position is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a current collector, a battery and a battery pack. BACKGROUND

[0002] In the prior art, the current collector of the battery is electrically connected with the tab of the electrode assembly and the shell of the battery, and specifically, the pin of the current collector is welded with the shell to form a welding area. After welding, the shell may be locally deformed due to external stress or internal stress, the deformation exerts a stretching action on the pin of the current collector, and the welding area as a whole may be broken to lose electrical connection, which needs to be improved. SUMMARY

[0003] Therefore, the present application aims to provide a current collector, a battery and a battery pack to solve the above-mentioned technical problems.

[0004] To achieve the above-mentioned purpose, the present application provides a current collector, comprising: a current collecting portion; a pin comprising a main body portion bent relative to the current collecting portion and an extension portion connected to the main body portion, the main body portion being connected to the current collecting portion, the extension portion and the main body portion extending along a first direction relative to the current collecting portion; the extension portion having a welding portion for welding connection with an external member; the extension portion having a first end and a second end disposed opposite each other along a width direction thereof, along the first direction, the extension portion being provided with a weak portion on a side of the welding portion close to the main body portion, the weak portion being distributed along a straight line trajectory, and the straight line trajectory being connected between the first end and the second end, the weak portion being used to bend or locally break when the pin is deformed while maintaining the relative fixation of the welding portion and the external member; wherein, along the width direction, the weak portion has a first weak portion and a second weak portion located on at least one side of the first weak portion, the shear strength of the first weak portion being less than that of the second weak portion.

[0005] Further, the first weak portion and the second weak portion are connected, and each side of the first weak portion in the width direction is provided with one second weak portion.

[0006] Further, the extension portion has a first side and a second side disposed opposite each other in a thickness direction thereof, the weak portion is a groove structure, and the groove structure is located on the first side and / or the second side, wherein the groove structure is continuously distributed from the first end to the second end. The groove structure is formed on the extension portion by at least one of a material removal process, a stamping process and a thinning process. The minimum thickness of the first weakened portion along the thickness direction of the extension portion is T1, the minimum thickness of the second weakened portion along the thickness direction of the extension portion is T2, and the minimum thickness of the main body portion is T3, wherein T1

[0007] Further, the weakened portion comprises an opening extending along the thickness direction of the extension portion and penetrating through the extension portion, and the opening is distributed in a continuous or discontinuous manner along the width direction.

[0008] Further, the distribution length of the first weakened portion along the width direction is L1, the welding portion has a welding preset area for welding connection with the external member, the length of the welding preset area along the width direction is L2, wherein L1≥L2; the length of the pin along the width direction is L3, and L1 / L3≤0.5.

[0009] Further, the weakened portion is arranged in a spaced manner with the welding preset area; along the first direction, the distance between the weakened portion and the welding preset area is D1, and D1≥0.1mm.

[0010] Further, along the width direction, the end portion of the first weakened portion close to the second weakened portion comprises a transition portion connected with the second weakened portion, and the thickness of the transition portion gradually decreases in the direction of the second weakened portion pointing to the first weakened portion; or, The transition portion comprises at least one transition weakened portion connected between the first weakened portion and the second weakened portion.

[0011] Based on the same inventive concept, the application further provides a battery comprising: a shell; an electrode assembly comprising a winding structure formed by winding, the winding structure having a winding central axis, the electrode assembly being provided with a tab at one end along the winding central axis, and the electrode assembly being accommodated in the shell; and the current collector of any one of the above, the current collecting portion is electrically connected with the tab, the pin is bent relative to the current collecting portion and forms a bent portion, so that the first side surface of the pin is assembled with the shell and the welding portion is welded with the shell; along the first direction, the bent portion is located on the side of the weakened portion close to the current collecting portion; and the bent portion is a material thinning structure relative to the current collecting portion.

[0012] Further, the shell comprises a circular end wall and a side wall connected to the end wall, the end wall and the side wall surround to form a receiving space for accommodating the electrode assembly, the side wall is recessed with a rolling groove towards the receiving space along the circumference of the circular end wall; along the winding central axis direction, the current collector is located between the rolling groove and the electrode assembly; the rolling groove comprises a ring-shaped first side close to the tab, and the welding portion is welded to the first side; the pin is bent relative to the welding portion at the second weak portion along the width direction, and is at least partially broken at the first weak portion.

[0013] Based on the same inventive concept, the application also provides a battery pack, comprising: any one of the above-mentioned batteries.

[0014] As can be seen from the above, the current collector provided by the application comprises a current collecting portion and a pin, the pin comprises a main body portion bent relative to the current collecting portion and an extension portion connected to the main body portion, the main body portion is connected to the current collecting portion, and the extension portion and the main body portion extend relative to the current collecting portion along a first direction; the extension portion has a welding portion for welding connection with an external member; wherein along the first direction, the extension portion is provided with a weak portion on a side of the welding portion close to the main body portion, the extension portion has a first end and a second end arranged opposite to each other along a width direction thereof, the weak portion is distributed along a straight line trajectory, and the straight line trajectory is connected between the first end and the second end, and the weak portion is used to be bent or partially broken when the pin is deformed, while maintaining the relative fixation of the welding portion and the external member; the bending deformation of the pin is guided to occur at the preset weak portion, avoiding welding defects or pin damage caused by random deformation. Along the width direction, the weak portion has a first weak portion and a second weak portion located on at least one side of the first weak portion, forming an obvious distribution difference, breaking the inherent thinking of the single and uniform design of the traditional weak feature. And the shear strength of the first weak portion is less than that of the second weak portion, wherein the first weak portion dominates the bending process, and its lower shear strength enables it to smoothly guide the yield bending, and the first weak portion can bend before the welding line area in the shell deformation process, avoiding the electrical connection failure caused by the bending and tearing of the welding line. The second weak portion maintains a relatively high shear strength, which has bending performance and also provides sufficient anti-breaking strength, thereby maintaining the strength stability of the bending position. The above design can effectively guide the pin bending process while ensuring the local strength, ensuring the accuracy and consistency of the bending, and providing strong support for the performance improvement and quality assurance of related products. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative labor.

[0016] Figure 1 A cross-sectional view of a cylindrical battery in the related art is shown. Figure 2 A three-dimensional structure of a current collector in an embodiment of the present application is shown. Figure 1 ; Figure 3 A three-dimensional structure of a current collector in an embodiment of the present application is shown. Figure 2 ; Figure 4 A partial enlarged view of a current collector in an embodiment of the present application is shown. Figure 1 ; Figure 2 A partial enlarged view of a current collector in an embodiment of the present application is shown. Figure 6 ; Figure 3 A partial enlarged view of a current collector in an embodiment of the present application is shown. Figure 7 ; Figure 8 A first partial cross-sectional view of a pin in an embodiment of the present application is shown. Figure 9 A second partial cross-sectional view of a pin in an embodiment of the present application is shown. Figure 1 A structure of a stepped transition weak portion in an embodiment of the present application is shown. Figure 10 ; Figure 2 A structure of a stepped transition weak portion in an embodiment of the present application is shown. Figure 11 ; Figure 12 A structure of a smooth transition weak portion in an embodiment of the present application is shown. Figure 1 A connection between a groove and a pin in an embodiment of the present application is shown.

[0017] Explanation of reference signs: 100, housing; 110, circular end wall; 120, side wall; 130, accommodation space; 140, rolling groove; 141, first side; 150, pole column; 160, opening; 200, electrode assembly; 210, winding structure; 300, current collector / first current collector / second current collector; 310, current collecting portion; 320, pin; 320a, first end; 320b, second end; 330, main body portion; 340, extension portion; 340a, first side surface; 340b, second side surface; 341, welding portion; 341a, welding preset area; 342, weak portion; 342a, first weak portion; 342b, second weak portion; 345, transition weak portion; 345a, third weak portion; 345b, fourth weak portion; 345c, first transition end; 345d, second transition end; 346, opening; 346a, first opening; 346b, second opening; 350, bending portion; 400, cover plate; X, first direction; Y, second direction; L, winding central axis. DETAILED DESCRIPTION

[0018] For the purposes of the present application, the technical solutions and advantages thereof are more clearly apparent, the following further describes the present application in detail with reference to specific examples and with reference to the accompanying drawings.

[0019] It should be noted that, unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be understood as their common meanings to those of ordinary skill in the art to which the present application belongs. The terms "first", "second", and similar terms used in the present application do not represent any order, number, or importance, but are only used to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships can also change accordingly.

[0020] The current collector 300 is a structure or component that collects current in a battery, and its main function is to concentrate and conduct the current generated by the electrode active material to form a larger current output, thereby realizing efficient conversion of chemical energy to electrical energy. The current collector 300 is widely used in various types of batteries, including cylindrical batteries, prismatic batteries, soft-pack batteries, etc., and the following will be described by taking the application of the current collector 300 in a cylindrical battery as an example.

[0021] Figures 1-11As a cross-sectional view of a cylindrical battery in the related art, the cylindrical battery includes a shell 100, one end of the shell 100 is provided with an opening 160, the opening 160 is in communication with an inner cavity of the shell 100. The other end of the shell 100 is provided with a pole 150, one end of the pole 150 is exposed, and the other end is located in the inner cavity through the shell 100. The inner cavity of the shell 100 contains an electrode assembly 200, the electrode assembly 200 includes a winding structure 210 wound into a winding structure 210, the winding structure 210 has a winding center axis L, the electrode assembly 200 is provided with a first tab (for example, a positive tab) at one end along the winding center axis L, and a second tab (for example, a negative tab) at the other end, the electrode assembly 200 is provided with a first current collector 300 on one side of the first tab, and the first tab, the first current collector 300 and the pole 150 are electrically connected. The electrode assembly 200 is provided with a second current collector 300 on one side of the second tab, and the second tab, the second current collector 300 and the shell 100 are electrically connected. In addition, the cylindrical battery also includes a cover plate 400 for plugging the opening 160.

[0022] Among them, the second current collector 300 includes a current collecting part 310 and at least one pin 320 (for example, 4), each pin 320 includes a main body part 330 and an extension part 340, the main body part 330 is connected with the current collecting part 310, the extension part 340 has a welding part 341 for welding connection with the shell 100, the welding part 341 of the pin 320 is bent towards the opening 160, and then welded with the shell 100, and a welding line area is formed in part of the welding part 341. The welding line area, the junction with the base material, the welding toe and the welding root and other parts form natural geometric discontinuity due to cross-section change, resulting in much higher local stress concentration coefficient than non-welding area. When the external stress and the welding residual tensile stress are superimposed, these high stress areas will first reach or exceed the material fracture strength threshold, thereby inducing the initiation and steady expansion of micro-cracks; in addition, the internal defects such as pores, non-metallic inclusions, incomplete penetration, micro-cracks and the like which are difficult to completely avoid during the welding process make them the congenital crack source, further reducing the toughness of the material. In addition, the welding metal and the heat affected zone usually have organization deterioration phenomena such as grain coarsening and brittle hard phase precipitation, and their ability to resist crack propagation is weaker than that of the base material, so under the same load condition, the crack propagation rate of the welding area is faster and the critical fracture stress is lower, and the whole presents a brittle fracture tendency much higher than that of the non-welding area.

[0023] More than that, after the current collector 300 is applied to the cylindrical battery, the opening 160 of the shell 100 at one end is subjected to the rolling process 140 after the welding wire area is formed. In the manufacturing process of the cylindrical battery, the rolling process is a key link, which not only can significantly enhance the sealing performance of the battery, but also can effectively improve the overall structural stability of the battery. Specifically, the rolling process can form a suitable structure to fix the cover plate 400. When the cover plate 400 is installed to the rolling structure 140, the cover plate 400 cooperates with the rolling structure through the bumping process, which can effectively prevent the leakage of the electrolyte and other substances in the battery, thereby ensuring the safety of the battery during use. For example, in some lithium-ion cylindrical batteries, the electrolyte contains organic solvents, and if these solvents leak, they may cause safety problems, such as reaction with moisture in the air to generate gas, etc.

[0024] In the rolling process, the shell 100 will be partially stretched and bent towards the axis of the shell 100 at the same time, and the pin 320 will also be bent towards the axis of the shell 100 due to the welding with the shell 100. The bending position of the pin 320 will mainly occur in the weak area of the material, and if the pin 320 as a whole is not designed to have a weak area, the tensile stress generated by the bending will be large, and the bending position will be too random, which cannot guarantee the shape after bending, and is also prone to conduct tensile stress, which may be transmitted to the weak welding wire area, causing the pin 320 to break or the welding wire to be torn and torn, etc. Thus, the failure of the pin 320 may be caused. In order to avoid these problems, a bending guide structure is designed on the extension part 340 of the pin 320 of the second current collector 300. The commonly used bending guide method is to thin the thickness, which can guide the pin 320 to bend at the thinning position during the rolling process, thereby avoiding the bending of the pin 320 at the welding wire position and causing the welding wire to be torn.

[0025] However, the traditional equal-thickness-thinning design has some limitations. The thickness of the equal-thickness-thinning area is uniform, if the thickness is too thick, the bending of the pin 320 may still occur at the welding wire area, causing the welding wire to be torn; if the thickness is too thin, the thinning area may be broken as a whole, thereby losing the electrical connection. In order to solve these problems, the structure design of the pin 320 needs to be improved to ensure that the pin 320 can bend at the appropriate weak part 342 before the welding wire area during the rolling process, so as to avoid the risk of welding wire tearing and pin 320 breaking.

[0026] It should be noted that the second current collector 300 applied in the cylindrical battery is taken as an example for description in the present application, that is, the current collector 300 mentioned in the subsequent embodiments refers to the second current collector 300 in the absence of special instructions. In addition, for the convenience of description, the extension direction of the extension part 340 relative to the main body part 330 is set as the first direction X, and the extension direction of the weak part 342 (or the guiding bending structure) on the pin 320 is set as the second direction Y, which can also be referred to as the width direction of the pin 320 or the extension part 340.

[0027] Hereinafter, the technical solutions of the present application will be described in detail through specific embodiments and in combination with Figures 2-4

[0028] In some embodiments, as shown in Figure 4 A current collector 300 includes a current collecting part 310, a pin 320 including a main body part 330 bent relative to the current collecting part 310 and an extension part 340 connected to the main body part 330, the main body part 330 being connected to the current collecting part 310, the extension part 340 and the main body part 330 extending along the first direction X relative to the current collecting part 310; the extension part 340 has a welding part 341 for welding connection with an external member; the extension part 340 has a first end 320a and a second end 320b arranged opposite to each other along the width direction thereof, along the first direction X, the extension part 340 is provided with a weak part 342 on the side of the welding part 341 close to the main body part 330, the weak part 342 is distributed along a straight line track, and the straight line track is connected between the first end 320a and the second end 320b, the weak part 342 is used to bend or partially break when the pin 320 is deformed while maintaining the relative fixation of the welding part 341 and the external member; along the second direction Y, the weak part 342 has a first weak part 342a and a second weak part 342b located on at least one side of the first weak part 342a, the shear strength of the first weak part 342a is less than that of the second weak part 342b.

[0029] ​Specifically, in the case of applying the current collector 300 to the battery, the outer member is the shell 100, and the extension portion 340 has a welding portion 341 connected to the shell 100. To facilitate the welding process, the extension portion 340 is bent relative to the main body portion 330 at a region near one side of the free end of the extension portion 340, and the bent portion relative to the main body portion 330 can be regarded as the welding portion 341. In addition, in order to further optimize the welding process and improve the stability of the structure, the extension portion 340 is provided with a weak portion 342, which can guide the bending deformation of the pin 320 to occur at the predetermined weak portion 342 during the processing of the rolling groove 140, and further, the weak portion 342 is arranged on the side of the welding portion 341 close to the main body portion 330, that is, the weak portion 342 will yield and bend before the welding area reaches the predetermined tensile stress, thereby avoiding the possibility of the welding area being pulled off when bearing the predetermined tensile stress due to random deformation.

[0030] Specifically, the extension portion 340 has a first side surface 340a and a second side surface 340b arranged opposite to each other in the thickness direction of the extension portion 340. Exemplarily, in the case where the extension portion 340 is not welded to the shell 100, the extension portion 340 can be in the same plane as the main body portion 330, and of course, it can also be bent relative to the main body portion 330, but in the case where the extension portion 340 is welded to the shell 100, the extension portion 340 will necessarily be bent relative to the main body portion 330 due to the welding requirement. In the case where the extension portion 340 is bent relative to the main body portion 330, the first side surface 340a is arranged close to the shell 100, and the second side surface 340b is arranged away from the shell 100. It should be noted that the thickness direction is perpendicular to the first direction X and the second direction Y.

[0031] Specifically, the weak portion 342 is distributed along the second direction Y from the first end 320a to the second end 320b, that is, the weak portion 342 presents a linear extension tendency in the second direction Y. The weak portion 342 is not a single structure, but includes a first weak portion 342a and a second weak portion 342b located on at least one side of the first weak portion 342a. In terms of mechanical properties, the shear strength of the first weak portion 342a is significantly less than that of the second weak portion 342b, which forms a significant difference in shear strength distribution, breaking the inherent thinking of traditional weak feature uniformity design, and instead adopting an innovative method of designing different weak degrees in different regions.

[0032] Specifically, the first weak part 342a can be directly connected with the second weak part 342b, or can be arranged with a spacing between the two. If the spacing area has the same thickness as the main body of the extension part 340, the spacing area should not be too long. If the spacing area is too long, the average shear strength of the weak part 342 as a whole will increase, the yield strength of the weak part 342 will weaken, and it is likely to affect the bending of the weak part 342 during the rolling groove process.

[0033] It should be noted that the shear strength of the second weak part 342b is greater than the first shear strength, and also matches the tensile strength of the welding line area, so that the welding line area realizes bending fatigue (bending) or fracture before reaching the preset tensile stress. The shear strength is used to represent the maximum shear stress per unit area. For example, the maximum shear stress of the welding line area is 250N±100N, the maximum shear stress of the first weak part 342a is 50~150N, and the maximum shear stress of the second weak part 342b is 350~1000N. That is, overall, the first weak part 342a dominates the bending process, and its lower shear strength enables it to smoothly guide the yield bending, and can bend or break before the welding line area during the rolling groove process, avoiding the electrical connection failure caused by the welding line bending and tearing. The second weak part 342b maintains a relatively high shear strength, which has bending performance and provides sufficient anti-fracture strength, thereby maintaining the strength stability of the bending position. This design can effectively guide the bending process of the pin 320 of the rolling groove process under the premise of ensuring local strength, ensuring the accuracy and consistency of the bending, and providing strong support for the performance improvement and quality assurance of related products.

[0034] In addition, in different application scenarios, the shear strength of the first weak part 342a and the second weak part 342b, as well as the relative position and size between the two, can be adjusted to meet different bending and welding requirements. For example, in some applications that require high bending accuracy, the bending flexibility can be improved by reducing the shear strength of the first weak part 342a; and in some applications that require high strength, the anti-fracture ability of the whole can be improved by increasing the shear strength of the second weak part 342b. This flexible adjustment capability makes the current collector 300 design widely applicable to various electronic devices and battery packages, and provides strong support for the performance improvement and quality assurance of products.

[0035] A current collector 300 according to this embodiment includes a current collector 310 and a pin 320. The pin 320 includes a main body 330 bent relative to the current collector 310 and an extension 340 connected to the main body 330. The main body 330 is connected to the current collector 310. The extension 340 and the main body 330 extend relative to the current collector 310 along a first direction X. The extension 340 has a welding portion 341 for welding to an external component. Along the first direction X, the extension 340 is positioned near the welding portion 341 close to the main body 330. A weak portion 342 is provided on one side. The extension 340 has a first end 320a and a second end 320b arranged opposite to each other along its width direction. The weak portion 342 is distributed along a straight line trajectory, and the straight line trajectory connects the first end 320a and the second end 320b. The weak portion 342 is used to bend or partially break when the pin 320 deforms, while maintaining the relative fixation of the welded part 341 and the external component. This guides the bending deformation of the pin 320 to occur at the predetermined weak portion 342, avoiding welding defects or damage to the pin 320 caused by random deformation. Along the width direction, the weak portion 342 has a first weak portion 342a and a second weak portion 342b located on at least one side of the first weak portion 342a, forming a significant distribution difference, breaking the inherent idea of ​​traditional single and uniform design of weak features. Furthermore, the shear strength of the first weak portion 342a is lower than that of the second weak portion 342b. The first weak portion 342a dominates the bending process, and its lower shear strength allows it to smoothly guide yield bending. It also bends before the bonding wire area during the deformation of the outer casing 100, avoiding electrical connection failure caused by bonding wire bending and tearing. The second weak portion 342b, on the other hand, maintains relatively high shear strength, providing sufficient anti-fracture strength while also possessing bending performance, thus maintaining the strength stability at the bending position. This design effectively guides the bending process of the pin 320 while ensuring local strength, ensuring the accuracy and consistency of the bending, and providing strong support for the performance improvement and quality assurance of related products.

[0036] In some embodiments, such as Figure 4 As shown, the first weak part 342a is connected to the second weak part 342b, and the first weak part 342a is provided with a second weak part 342b on each side of the second direction Y.

[0037] In this embodiment, the first weak portion 342a and the second weak portion 342b are directly connected, without the gap region mentioned in the previous embodiments. That is, the weak portion 342 is a continuous structure, making it easier for the entire weak portion 342 to yield. The first weak portion 342a has lower shear strength, allowing it to guide deformation smoothly during bending, while the second weak portion 342b has higher shear strength, ensuring the strength and stability of the connection. In this embodiment, the first weak portion 342a is connected to a second weak portion 342b on each side of the second direction Y. This design not only improves structural stability but also provides better mechanical balance during bending and yielding.

[0038] Specifically, when the first weak part 342a yields, partial cracking is likely to occur. If a second weak part 342b is connected only to one side of the first weak part 342a, the cracked portion may cause an adverse tearing effect on the second weak part 342b, thus affecting the stability and reliability of the overall structure. However, by connecting a second weak part 342b to each side of the first weak part 342a, this tearing problem can be effectively avoided. The second weak parts 342b on both sides can share the stress, preventing structural failure due to localized cracking.

[0039] In this embodiment, the current collector 300 is directly connected to the first weak part 342a and the second weak part 342b, making the weak part 342b more prone to yielding. This allows for smooth deformation guidance during bending, preventing bending failure. Furthermore, the first weak part 342a has a second weak part 342b on each side of the second direction Y. These two second weak parts 342b can share the stress, effectively preventing structural failure caused by local cracking of the first weak part 342a, thus improving the overall stability and reliability of the structure.

[0040] In some embodiments, such as Figure 7 As shown, the extension 340 has a first side surface 340a and a second side surface 340b disposed opposite to each other in its thickness direction, and the weak portion 342 is a groove structure located on the first side surface 340a and / or the second side surface 340b.

[0041] In this embodiment, the groove structure is continuously distributed from the first end 320a to the second end 320b. This continuous distribution design not only effectively guides bending but also maintains structural stability during bending. Specifically, the continuously distributed groove structure forms an uninterrupted weak region along the second direction Y of the entire extension 340. This allows stress to be evenly distributed along the entire length of the groove structure during bending, thereby achieving smooth and controllable deformation and avoiding excessive deformation or fracture caused by local stress concentration, ensuring the reliability and consistency of the bending process. Furthermore, the continuously distributed groove structure has significant advantages in the laser welding process between the pin 320 and the housing 100. During laser welding, the laser beam needs to be precisely applied to the welding area to ensure welding quality and structural integrity. If the groove structure has perforations or other forms of fracture, it may cause laser beam leakage during welding, potentially burning the separator in the cell and affecting the electrochemical performance of the battery.

[0042] Furthermore, the weak portion 342 is located on either the first side 340a or the second side 340b, primarily affecting the opening direction of the groove structure. Specifically, before the grooving process, the first side 340a is positioned closer to the housing 100, and the second side 340b is positioned further away from the housing 100. When the groove structure is located on the first side 340a, the opening of the groove structure faces the housing 100; when the groove structure is located on the second side 340b, the opening of the groove structure faces away from the housing 100 (i.e., towards the axis of the housing 100). During the grooving process, the housing 100, along with the bonding area of ​​the pin 320, deforms towards the axis of the housing 100. If the opening of the groove structure faces the housing 100, the bending deformation process of the pin 320 is the process in which the two sides of the groove structure move away from each other in its extension direction. This mutually opposing bending process is easier to perform; that is, when the opening of the groove structure faces the housing 100, the yielding performance of the weak portion 342 is better during the grooving process. Conversely, if the opening of the groove structure faces away from the housing 100, the bending deformation process of the pin 320 is the process of the two sides of the groove structure moving closer to each other in its extension direction. This bending process of moving closer to each other can avoid excessive bending deformation of the weak part 342, thereby improving the stability and reliability of the structure.

[0043] The groove structure is formed on the extension 340 using at least one of the following processes: material removal, stamping, and upsetting. Material removal is a processing method that removes material using physical or chemical methods to form the desired shape. In this embodiment, techniques such as laser cutting, electrical discharge machining, or chemical etching can be used to precisely remove material from the surface of the extension 340 to form the groove structure. Stamping is a processing method that shapes material using a mold and a press. In this embodiment, a punching die can be used to punch the desired groove structure onto the extension 340. Upsetting is a processing method that forms the desired structure by locally thinning the material. In this embodiment, methods such as local upsetting or extrusion can be used to thin the material in specific areas of the extension 340, forming the groove structure.

[0044] Additionally, it should be noted that the general thinning process involves pressing and thinning the foil material of the lead 320 extension 340 with a pressure rod to create a groove structure. Then, to facilitate welding of the lead 320 to the housing 100, the extension 340 of the lead 320 is bent. This method involves thinning first and then bending, which has the disadvantage that bending will cause uneven thickness of the previously thinned groove structure, resulting in stress. Therefore, the above thinning process can be replaced by bending first and then pressing and thinning, thereby making the thickness of the thinned groove structure more consistent.

[0045] In this embodiment, the opening direction of the groove structure can be adjusted by setting the groove structure on the first side 340a and / or the second side 340b. When the groove structure is set on the first side 340a, the groove structure opening 160 faces the outer shell 100, and the bending deformation process of the pin 320 is a process in which the two sides of the groove structure move away from each other. This design makes the bending process easier and significantly improves the yield performance of the weak part 342 during the grooving process. Conversely, when the groove structure is set on the second side 340b, the groove structure opening 160 faces away from the outer shell 100, and the bending deformation process is a process in which the two sides of the groove structure move closer to each other. This design can avoid excessive bending deformation of the weak part 342, thereby improving the stability and reliability of the structure. This provides more possibilities for battery processing and packaging, meeting the needs of different process requirements and application scenarios, thereby improving the overall performance and lifespan of the battery.

[0046] In some embodiments, such as Figure 8 , Figure 6As shown, the minimum thickness of the first weak portion 342a along the thickness direction of the extension 340 is T1, the minimum thickness of the second weak portion 342b along the thickness direction of the extension 340 is T2, and the minimum thickness of the main body 330 is T3, where T1 < T2 ≤ T3. That is, the minimum thickness T1 of the first weak portion 342a is the thinnest, making it easier to yield during bending, thereby guiding deformation and preventing yielding in the bonding wire area that could lead to wire tearing. The minimum thickness T2 of the second weak portion 342b is relatively thicker than the minimum thickness T2 of the first weak portion 342a, giving it sufficient strength to withstand the stress during the grooving process and ensuring the stability of the connection. The minimum thickness T3 of the main body 330 is greater than or equal to the minimum thickness T2 of the second weak part 342b. The minimum thickness of the main body 330 is the same as the minimum thickness of the welded part 241 before welding. Since the thickness of the extension 340 after welding is not easy to measure, the minimum thickness of the welded part 241 before welding is limited by the minimum thickness of the main body 330 here to ensure that the welded part 341 has sufficient strength and stability during welding, while meeting the requirements of the welding process.

[0047] It should be noted that while the shear strength of the bonding wire region mentioned in the previous embodiment is less than that of the second weak portion 342b, the minimum thickness T3 of the welding portion 341 in this embodiment is greater than or equal to the minimum thickness T2 of the second weak region, and the two are not contradictory. Specifically, the welding portion 341 only forms a bonding wire region after welding with the inner wall of the outer shell 100, and the local melting and flow of the material during the welding process causes the thickness of the bonding wire region to be thinner than that of the welding portion 341, thereby reducing the shear strength of the bonding wire region accordingly. To prevent the extension portion 340 of the pin 320 from bending at the bonding wire region during the grooving process, the minimum thickness T1 of the first weak portion 342a can be set smaller than the thickness of the bonding wire region, making its shear strength smaller than that of the bonding wire region, which is beneficial for guiding bending. At the same time, the minimum thickness T2 of the second weak portion 342b is set larger than the thickness of the bonding wire region, making its shear strength larger than that of the bonding wire region, thereby ensuring the connection strength. This design not only optimizes the bending and welding process, but also improves the stability and reliability of the structure, effectively avoiding problems such as wire tearing and pin 320 soldering failure.

[0048] Additionally, 0.5 ≤ T2 / T3 ≤ 1, 0.2 ≤ T1 / T3 ≤ 0.75, and 0.1 mm ≤ T3 ≤ 0.3 mm are examples. T2 / T3 can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, and T1 / T3 can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.75. These examples are not intended to limit the value; specific values ​​can be set according to product requirements. The ratio of T2 / T3 cannot be too small, otherwise the connection strength of the second weak part 342b cannot be guaranteed. If T2 / T3 is too small, the thickness T2 of the second weak part 342b will be relatively thin, which may result in the second weak part 342b being unable to withstand sufficient stress during welding and use, thus affecting the stability and reliability of the structure. Conversely, T2 / T3 cannot be too large. If it is too large, the thickness T2 of the second weak part 342b will be relatively thick, which will increase the difficulty of bending and make it difficult to achieve the expected bending effect during grooving. Therefore, the range of 0.5≤T2 / T3≤1 ensures that the second weak part 342b has sufficient strength without being too thick and affecting bending performance. The ratio of T1 / T3 cannot be too small. If it is too small, the first weak part 342a is prone to breakage during the thinning process. If T1 / T3 is too small, the thickness T1 of the first weak part 342a will be relatively thin, which may lead to the first weak part 342a being prone to breakage during processing, especially in the thinning process, thus affecting production efficiency and product quality. Conversely, T1 / T3 cannot be too large either. If it is too large, the thickness T1 of the first weak part 342a will be relatively thick, which will increase the difficulty of bending and make it difficult to achieve the expected bending effect during grooving, without significantly improving the weld line tearing problem. Therefore, the range of 0.2≤T1 / T3≤0.75 ensures that the first weak part 342a is thin enough to guide bending, but not so thin that it affects processing and performance.

[0049] This embodiment optimizes the performance of the current collector 300 during bending and welding processes by designing the thickness parameters of the weak portion 342. The minimum thickness T1 of the first weak portion 342a is the thinnest, making it easier to yield during bending, thereby guiding deformation and preventing yielding in the weld area that could lead to weld line tearing. The minimum thickness T2 of the second weak portion 342b is relatively thicker than that of the first weak portion 342a, giving it sufficient strength to withstand the stress during the grooving process and ensuring the stability of the connection. The minimum thickness T3 of the welded portion 341 is greater than or equal to the minimum thickness T2 of the second weak portion 342b, ensuring that the welded portion 341 has sufficient strength and stability during welding, while also meeting the requirements of the welding process. Furthermore, by reasonably setting the ratio ranges of T2 / T3 and T1 / T3, it is ensured that the second weak portion 342b has sufficient strength without being too thick to affect bending performance, while the first weak portion 342a has sufficient thinness to guide bending without being too thin to affect processing and performance. This design not only optimizes the bending and welding process, but also improves the stability and reliability of the structure, effectively avoiding problems such as wire bonding tearing and pin 320 welding failure, providing strong support for the performance improvement and quality assurance of battery packaging.

[0050] In some embodiments, reference Figure 5 The weak portion 342 includes an opening 346 extending along the thickness direction of the extension portion 340 and penetrating the extension portion 340, the opening 346 being distributed continuously or discontinuously along the second direction Y.

[0051] In the aforementioned embodiments, the weak portion 342 is described as a continuous groove structure. In this parallel embodiment, the weak portion 342 is configured as a continuous or discontinuous opening 346.

[0052] When the openings 346 are continuously distributed along the second direction Y, a continuous weak region is formed. For example, the first weak portion 342a has a first opening 346a, and the second weak portion 342b has a second opening 346b. The first opening 346a and the second opening 346b are interconnected, meaning the openings 346 are continuously distributed along the second direction Y. The diameter of the first opening 346a in the first direction X is larger than the diameter of the second opening 346b in the first direction X, so that the shear strength of the first weak portion 342a is less than the shear strength of the second weak portion 342b. This continuously distributed opening 346 design helps improve the yield characteristics of the pin 320, making it easier to guide bending during the grooving process.

[0053] When the openings 346 are discontinuously distributed along the second direction Y, a weak region with multiple independent weak points is formed. For example, the first weak portion 342a has multiple discontinuous first openings 346a, and the second weak portion 342b has multiple discontinuous second openings 346b. The number of second openings 346b is less than the number of first openings 346a, or the diameter of the second openings 346b is smaller than the diameter of the first openings 346a, so that the shear strength of the first weak portion 342a is less than the shear strength of the second weak portion 342b. This discontinuous distribution of the openings 346 creates multiple independent weak points, allowing stress to be dispersed at multiple weak points during bending, thereby achieving multi-point guided bending deformation, making the bending deformation process smoother, and resulting in a more stable deformed structure.

[0054] This embodiment significantly improves the performance of the pin 320 during bending and welding by forming a weak portion 342 through an opening 346 extending along the thickness direction on the extension 340. When the openings 346 are continuously distributed along the second direction Y, an uninterrupted weak region is formed. By adjusting the apertures of the first opening 346a and the second opening 346b, the shear strength of the first weak portion 342a is made less than that of the second weak portion 342b, thereby optimizing the yield characteristics of the pin 320 and making it easier to guide bending during the grooving process. When the openings 346 are discontinuously distributed along the second direction Y, multiple independent weak points are formed. By adjusting the number and aperture of the openings 346, the shear strength of the first weak portion 342a is made less than that of the second weak portion 342b, thereby achieving multi-point guided bending deformation, making the bending process smoother and the deformed structure more stable.

[0055] In some embodiments, such as Figure 5 As shown, the first weak portion 342a has a distribution length of L1 along the second direction Y. The welding portion 341 has a welding preset area 341a, which is used for welding connection with the external component. The length of the welding preset area 341a along the second direction Y is L2. Wherein, L1≥L2; the length of the pin 320 in the second direction Y is L3, and L1 / L3≤0.5.

[0056] Specifically, when the current collector 300 of this application is applied to a battery, the external component is the battery casing 100. Furthermore, after the welding preset area 341a is welded to the casing 100, a weld line area is formed, wherein the length of the weld line area along the second direction Y is L2, and the length of the weld line area along the first direction X is M1.

[0057] In this design, the length L1 of the first weak portion 342a is greater than or equal to the length L2 of the bonding wire region. This is to ensure that the first weak portion 342a can effectively guide deformation during bending, thereby protecting the bonding wire region. Specifically, the first weak portion 342a is designed to yield before the bonding wire region during bending, thereby reducing stress concentration in the bonding wire region. By setting L1≥L2, it can be ensured that the first weak portion 342a forms a protective area on the side of the bonding wire region closer to the main body 330, preventing the bonding wire region from being subjected to excessive stress during bending, thereby reducing the risk of bonding wire tearing.

[0058] The length of the first weak portion 342a along the first direction X is M1, and M1 can be set to 0.2mm ≤ M1 ≤ 1.0mm. If M1 is too small, for example, less than 0.2mm, it will adversely affect the strength and service life of the upsetting die. Because a thinner first weak portion 342a requires a more precise and stronger die, this not only increases the manufacturing difficulty and cost of the die, but may also lead to rapid wear and damage of the die during use, thereby affecting production efficiency and product quality. Conversely, if M1 is too large, i.e., more than 1.0mm, although it may enhance the structural strength to some extent, it will reduce the weldable space of the welded portion 341. That is, a larger M1 will make the pre-welded area 341a narrower, thereby increasing the welding difficulty. Therefore, setting M1 in the range of 0.2mm to 1.0mm ensures the strength and service life of the die while providing sufficient space for welding operations to achieve a high-quality welding effect.

[0059] Furthermore, the shear strength of the first weak portion 342a needs to be lower than that of the weld wire region. This is because during bending, the first weak portion 342a needs to yield before the weld wire region to guide deformation. If the shear strength of the first weak portion 342a is higher than or equal to the shear strength of the weld wire region, the weld wire region may yield before the first weak portion 342a during bending, leading to weld wire tearing. Therefore, by designing the shear strength of the first weak portion 342a to be lower than that of the weld wire region, it can be ensured that the first weak portion 342a yields before the weld wire region during bending, thereby protecting the weld wire region and reducing the risk of weld wire tearing.

[0060] Furthermore, the length of the first weak portion 342a cannot be too long, and must satisfy L1 / L3 ≤ 0.5. Examples can be 0.1, 0.2, 0.3, 0.4, and 0.5. These examples are not intended to limit the length, and the specific length can be set according to product requirements. That is, the length of the first weak portion 342a in the second direction Y must be less than or equal to half the length of the pin 320 in the second direction Y. If the distribution length L1 of the first weak portion 342a is too long, exceeding half the length L3 of the pin 320, then if the first weak portion 342a breaks during the sealing process of the groove 140, the second weak portions 342b on both sides may not maintain a reliable connection, thereby compromising the stability of the entire pin 320 structure and potentially even causing an interruption of the electronic pathway. By limiting L1 to within half of L3, even if the first weak portion 342a breaks after the groove 140 is sealed, the second weak areas on both sides can still maintain sufficient strength and connectivity, ensuring the stability and reliability of the electronic pathway.

[0061] In addition, since the pin 320 needs to achieve the overcurrent capacity through the welding preset area 341a, the length M2 of the welding preset area 341a (or the welding wire area) in the first direction X is designed to be 0.5≤M2≤3mm. This ensures that the welding preset area 341a (or the welding wire area) meets the current transmission requirements of the battery and can guarantee sufficient accuracy and reliability during the welding process, thereby improving the overall performance and safety of the battery.

[0062] In some embodiments, such as Figures 9-11 As shown, the weak portion 342 is spaced apart from the pre-welded welding area 341a; along the first direction X, the distance between the weak portion 342 and the pre-welded welding area 341a is D1, where D1 ≥ 0.1 mm. This design ensures sufficient space between the weak portion 342 and the pre-welded welding area 341a, thereby avoiding damage to the weak portion 342 caused by heat during the welding process. When D1 is less than 0.1 mm, the pre-welded welding area 341a is too close to the weak portion 342, and the heat generated during the welding process may have a heat effect on the weak portion 342, causing tearing at the location of the weak portion 342 during the sealing process. Furthermore, when D1 is less than 0.1 mm, because the weld line area and the first weak area are closely connected, they will pull each other when the groove 140 is bent, causing the weld line area and the first weak area to connect together, resulting in tearing, which seriously affects the quality and performance of the product. By setting D1≥0.1mm, the influence of the welding and grooving processes on the weak part 342 can be effectively avoided, ensuring the structural integrity and stability of the weak part 342, thereby improving the reliability and durability of the entire current collector 300 during welding and use.

[0063] In some embodiments, such as Figure 9As shown, along the second direction Y, the end of the first weak portion 342a near the second weak portion 342b includes a transition portion connected to the second weak portion 342b. In the direction from the second weak portion 342b to the first weak portion 342a, the thickness of the transition portion gradually decreases. To achieve this gradual decrease in the thickness of the transition portion, two methods can be used: a stepped transition and a smooth transition.

[0064] Among them, such as Figure 10 , Figure 11 As shown, the stepped transition is achieved by providing at least one transition weak portion 345 of different thickness between the first weak portion 342a and the second weak portion 342b. Specifically, the transition portion includes at least one transition weak portion 345, which connects the first weak portion 342a and the second weak portion 342b. In the direction from the second weak portion 342b to the first weak portion 342a, the thickness of each transition weak portion 345 decreases in a stepped manner, and the connecting portions of each transition weak portion 345 are all chamfered transitions. For example, the transition weak portion 345 includes a third weak portion 345a and a fourth weak portion 345b. In the direction from the first weak portion 342a to the second weak portion 342b, the first weak portion 342a, the third weak portion 345a, the fourth weak portion 345b and the second weak portion 342b are connected sequentially, and the thickness of the third weak portion 345a is less than the thickness of the fourth weak portion 345b. The maximum shear stress of the first weak region is 50~150N, the maximum shear stress of the third weak region is 200~300N, the maximum shear stress of the fourth weak region is 300~400N, and the maximum shear stress of the second weak region is 400~1000N. That is, the shear stress of the first weak region, the third weak region, the fourth weak region and the second weak region gradually increases. That is, in the process of yielding and bending of the pin 320 caused by the grooving process, the transition portion needs to work with the first weak portion 342a to guide the yielding and bending, and also needs to work with the second weak portion 342b to stabilize the connection. The above design allows for precise control of thickness at different transition stages, thus better adapting to different structural requirements and stress distributions.

[0065] Among them, such as Figure 1As shown, a smooth transition is achieved through continuous thickness variation. Specifically, the transition portion has a first transition end 345c and a second transition end 345d disposed opposite to each other in the second direction Y. The first transition end 345c is connected to the first weak portion 342a, and the second transition end 345d is connected to the second weak portion 342b. The thickness of the transition portion at the second transition end 345d is greater than the thickness at the first transition end 345c, and the connection between the first transition end 345c and the first weak portion 342a is a smooth transition. The thickness of the second transition end 345d is less than the thickness of the second weak portion 342b. This smooth transition method can provide a more uniform stress distribution, reduce stress concentration caused by abrupt changes in thickness, and thus further improve the stability and reliability of the structure.

[0066] Furthermore, the thickness of the second transition end 345d is less than the thickness of the second weak portion 342b. This is mainly because during the yielding and bending process of the pin 320 caused by the grooving process, the second weak portion 342b primarily serves a connecting role, ensuring the integrity and stability of the structure. The transition weak portion 345, on the other hand, needs to work in conjunction with the first weak portion 342a to guide the yielding and bending process, making the bending process smoother and more uniform, and avoiding structural damage caused by excessive local stress. Therefore, by carefully designing the thickness of the second transition end 345d, it can effectively disperse stress while fulfilling both the connecting and guiding functions, reducing stress concentration caused by abrupt changes in thickness.

[0067] In this embodiment, the thickness of the transition section between the second weak part 342b and the first weak part 342a is gradually reduced through two transition methods: a stepped transition and a smooth transition. The stepped transition uses multiple transition weak parts 345 of varying thicknesses, with the thickness of each transition weak part 345 decreasing in a stepped manner, and the shear strength of each transition weak part 345 gradually decreasing. The smooth transition is achieved through continuous thickness variation. The first transition end 345c of the transition section is smoothly connected to the first weak part 342a and is relatively thin, while the second transition end 345d is connected to the second weak part 342b and is thicker but less than the second weak part 342b. The transition sections formed by these two transition methods, during the yielding and bending process of the pin 320 caused by the grooving process, not only guide the yielding and bending in conjunction with the first weak part 342a, but also provide a stable connection with the second weak part 342b. Furthermore, they can effectively disperse stress, reduce stress concentration, and improve the stability and reliability of the structure.

[0068] In some embodiments, such as Figure 12 , Figure 1As shown, a battery includes: a housing 100; an electrode assembly 200 including a wound structure 210 formed by winding, the wound structure 210 having a winding central axis L, the electrode assembly 200 having a tab at one end along the winding central axis L, the electrode assembly 200 being housed within the housing 100; and a current collector 300 as described in any of the preceding embodiments, the current collector 310 being electrically connected to the tab, the lead 320 being bent relative to the current collector 310 to form a bent portion 350, such that a first side surface 340a of the lead 320 is fitted to the housing 100 and the welding portion 341 is welded to the housing 100; along the first direction X, the bent portion 350 is located on the side of the weak portion 342 near the current collector 310; the bent portion 350 is a material thinning structure relative to the current collector 310.

[0069] Specifically, in the case where the current collector 300 is applied to a cylindrical battery, the tab in this embodiment is a negative tab. As mentioned in the previous embodiment, the pin 320 includes a connected main body 330 and an extension 340. The main body 330 is connected to the current collector 310, and the extension 340 has a welding portion 341 connected to the housing 100. A portion of the welding portion 341 (i.e., the welding preset area 341a) forms a weld line area after welding with the housing 100. Furthermore, to facilitate the welding process, the area of ​​the extension 340 near its free end is bent relative to the main body 330; this bent portion relative to the main body 330 can be considered the welding portion 341. That is, the pin 320 is bent relative to the current collector 310 to form a bent portion 350, so that the first side 340a of the pin 320 is assembled with the housing 100. After assembly, it is convenient for the welding portion 341 to be welded to the housing 100 to form a weld line area.

[0070] Furthermore, along the first direction X, the bend 350 is located on the side of the weak portion 342 closer to the current collector 310. The bend 350 not only facilitates the welding of the pin 320 to the housing 100, but its thinned design also helps to disperse and alleviate stress that may occur during welding and use. Because the bend 350 is close to the current collector 310, it provides a relatively stable support point during welding, ensuring the strength and reliability of the weld. Simultaneously, this arrangement also helps to create a more uniform stress distribution in the overall battery structure, reducing structural damage that may result from stress concentration. Especially during the charging and discharging process, the electrode assembly 200 undergoes expansion and contraction; the presence of the bend 350 effectively buffers these changes, protecting the weak portion 342 from excessive stress, thereby enhancing the overall stability and durability of the battery.

[0071] In some embodiments, such as Figure 12 ,​ As shown, the housing 100 includes a circular end wall 110 and a side wall 120 connecting the circular end wall 110. The circular end wall 110 and the side wall 120 enclose a receiving space 130 for receiving the electrode assembly 200. The side wall 120 is recessed into the receiving space 130 along the circumference of the circular end wall 110. Along the winding center axis L, the current collector 300 is located between the groove 140 and the electrode assembly 200. The groove 140 includes an annular first side 141 near the tab. The welding part 341 is welded to the first side 141. The pin 320 is bent relative to the welding part 341 along the second direction Y at the second weak part 342b, and is at least partially broken at the first weak part 342a.

[0072] The circular end wall 110 and the side wall 120 connecting the circular end wall 110 constitute the casing 100 of the cylindrical battery. The grooving machine uses a rolling tool (such as a roller or a cutter) to apply pressure toward the receiving space 130 on the side wall 120 of the cylindrical casing 100, causing the material of the casing 100 to undergo plastic deformation, thereby forming a groove 140. The formed groove 140 includes an annular first side 141 near the electrode tab. Before the grooving process, the welding part 341 is welded to the part of the casing 100 to be grooved 140. After the grooving process, the part of the casing 100 is grooved to form the groove 140, thus the welding part 341 is welded to the first side 141 of the groove 140. In addition, during the grooving process, the first weak part 342a yields and guides the lead 320 to bend relative to the welded part 341 along the second direction Y at the weak part 342. Since the shear strength of the first weak part 342a is relatively small, it will break at least in part during the yielding and bending process. This breakage is beneficial to the release of the overall bending stress of the weak part 342 and to the connection stability of the second weak part 342b, thereby improving the overall performance and reliability of the battery.

[0073] Based on the same inventive concept and in conjunction with the descriptions of batteries in the above embodiments, this embodiment provides a battery pack that has the corresponding technical effects of the batteries in the above embodiments, which will not be repeated here.

[0074] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of this application as described above, which are not provided in the details for the sake of brevity.

[0075] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A current collector, characterized in that, include: Collection section; The pin includes a main body portion bent relative to the current collector and an extension portion connected to the main body portion, the main body portion being connected to the current collector portion, the extension portion and the main body portion extending relative to the current collector portion along a first direction; the extension portion has a welding portion for welding connection to an external component; The extension has a first end and a second end disposed opposite to each other along its width direction. Along the first direction, the extension has a weak portion on the side of the welded portion closer to the main body. The weak portion is distributed along a straight line trajectory, and the straight line trajectory connects the first end to the second end. The weak portion is used to bend or partially break when the pin is deformed while maintaining the relative fixation between the welded portion and the external component. Along the width direction, the weak portion has a first weak portion and a second weak portion located on at least one side of the first weak portion, wherein the strength of the first weak portion is less than the shear strength of the second weak portion.

2. The current collector according to claim 1, characterized in that, The first weak part is connected to the second weak part, and the first weak part has a second weak part on each side of the width direction.

3. The current collector according to claim 2, characterized in that, The extension has a first side and a second side disposed opposite to each other in its thickness direction, and the weak portion is a groove structure located on the first side and / or the second side; wherein the groove structure is continuously distributed from the first end to the second end; The groove structure is formed on the extension using at least one of the following processes: material removal process, stamping process, and thinning process; The minimum thickness of the first weak part along the thickness direction of the extension is T1, the minimum thickness of the second weak part along the thickness direction of the extension is T2, and the minimum thickness of the main body is T3, wherein T1 < T2 ≤ T3, 0.5 ≤ T2 / T3 ≤ 1, and 0.2 ≤ T1 / T3 ≤ 0.

75.

4. The current collector according to claim 1, characterized in that, The weak portion includes a plurality of openings extending along the thickness direction of the extension and penetrating the extension, the openings being distributed continuously or discontinuously along the width direction.

5. The current collector according to claim 1, characterized in that, The first weak part has a distribution length of L1 along the width direction. The welding part has a welding preset area for welding connection with the external component. The length of the welding preset area along the width direction is L2, where L1≥L2. The length of the pin in the width direction is L3, where L1 / L3≤0.

5.

6. The current collector according to claim 1, characterized in that, The weak part is spaced apart from the welding preset area; along the first direction, the distance between the weak part and the welding preset area is D1, where D1 ≥ 0.1 mm.

7. The current collector according to claim 3, characterized in that, Along the width direction, the end of the first weak portion near the second weak portion includes a transition portion connected to the second weak portion, and the thickness of the transition portion gradually decreases in the direction from the second weak portion to the first weak portion; or, The transition portion includes at least one transition weak portion, which connects the first weak portion and the second weak portion; in the direction from the second weak portion to the first weak portion, the thickness of each transition weak portion decreases in a stepwise manner.

8. A battery, characterized in that, include: shell; An electrode assembly includes a wound structure having a central axis, the electrode assembly having an electrode tab at one end along the central axis, and the electrode assembly being housed within the housing. And the current collector according to any one of claims 1 to 7, wherein the current collector is electrically connected to the tab, the pin is bent relative to the current collector to form a bent portion, so that a first side of the pin is fitted to the housing and the welding portion is welded to the housing; along the first direction, the bent portion is located on the side of the weak portion near the current collector; the bent portion is a material thinning structure relative to the current collector.

9. The battery according to claim 8, characterized in that, The housing includes a circular end wall and a side wall connecting the end wall. The end wall and the side wall enclose a receiving space for receiving the electrode assembly. The side wall has a groove recessed in the circumference of the circular end wall toward the receiving space. Along the winding center axis, the current collector is located between the groove and the electrode assembly; the groove includes an annular first side near the tab, and the weld is welded to the first side; the pin bends relative to the weld in the width direction at the second weak point, and is at least partially broken at the first weak point.

10. A battery pack, characterized in that, include: The battery according to any one of claims 8 to 9.

Images