Positive collector plate welding structure

Abstract

The utility model relates to an anode collector plate welding structure. Relates to the technical field of new energy batteries. The battery specifically comprises a battery cell arranged in a battery shell, a cover cap fixedly connected with the battery shell, and a positive electrode collector plate for conducting a positive electrode of the battery cell with the cover cap, the positive collector plate comprises a plate body part welded with a positive pole lug of the battery cell, a tail body part welded with the inner side of the cap, and a connecting part for connecting the plate body part and the tail body part, the plate body part, the tail body part and the connecting part are of an integrated structure, and the plate body part, the tail body part and the connecting part form a Z-shaped folding structure. The positive collector plate comprises the plate body part, the tail body part and the connecting part, the Z-shaped folding structure is formed by the plate body part, the tail body part and the connecting part, and the included angle of the Z-shaped folding structure is 3-10 degrees, so that the occupation of the space in the shell can be reduced, the space in the shell can be saved, the pulling effect on a welding spot can be reduced, and the open circuit of the battery can be prevented.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a positive electrode current collector welding structure. Background Technology

[0002] Existing cylindrical lithium-ion batteries generally include a casing and a cap. The battery cell is housed inside the casing, which has a slot structure. The slot of the casing and the cap are connected in a closed manner. The positive electrode of the battery cell is connected to the end face of the cap located inside the casing through a positive electrode tab, so the cap is positively charged. The negative electrode of the battery cell is connected to the casing through a negative electrode tab, so the casing is negatively charged.

[0003] In cylindrical lithium-ion batteries, the positive electrode is typically connected to the positive electrode tab of the cell by welding one end of the positive current collector to the positive electrode tab of the cell and the other end of the cap located inside the casing. This allows the positive electrode of the cell to be led out through the cap.

[0004] In the prior art, when the positive current collector connects the end face of the cell's electrode tab and cap located inside the casing, it is usually folded in a C-shape between the positive electrode tab and the cap. On the one hand, this occupies a lot of space inside the casing, which is not conducive to the integration of large-capacity batteries. On the other hand, during the battery assembly process, the solder joints of the positive current collector are easily pulled, which may cause the solder joints of the positive current collector to break, resulting in a battery open circuit. Utility Model Content

[0005] The purpose of this utility model is to provide a positive electrode current collector welding structure that addresses the shortcomings of the prior art. This structure can reduce the space occupied inside the casing, save space, and reduce the pulling effect on the welding points, thus preventing battery circuit breakage.

[0006] This utility model proposes a positive electrode current collector welding structure, including a battery cell disposed inside a battery casing, a cap fixedly connected to the battery casing, and a positive electrode current collector that connects the positive electrode of the battery cell to the cap. The positive electrode current collector includes a disk body portion welded to the positive electrode tab of the battery cell, a tail portion welded to the inner side of the cap, and a connecting portion connecting the disk body portion and the tail portion. The disk body portion, the tail portion, and the connecting portion are an integral structure. The disk body portion, the tail portion, and the connecting portion form a Z-shaped folding structure, and the included angle of the Z-shaped folding structure is 3° to 10°.

[0007] Furthermore, the tops of the multiple positive electrode tabs of the battery cell are flattened on the same horizontal plane to form a flattened layer, and the disk body is welded to the flattened layer.

[0008] Furthermore, the cap includes a top cover plate, an explosion-proof sheet, an isolation ring, and a bottom cover plate arranged sequentially from the outside to the inside. The central axes of the top cover plate, the explosion-proof sheet, the isolation ring, and the bottom cover plate are on the same straight line. The tail portion is welded to the bottom cover plate.

[0009] Furthermore, the disc body has a first end and a second end that are disposed opposite to each other, and the connecting part connects the second end to the tail body, wherein the length from the first end to the second end is in the range of 12mm to 16mm.

[0010] Furthermore, the distance between the first end and the inner wall of the battery casing ranges from 1mm to 3.5mm.

[0011] Furthermore, the distance between the second end and the inner wall of the battery casing ranges from 3mm to 10mm.

[0012] Furthermore, the tail section is welded to the bottom cover plate at a position off the central axis.

[0013] Furthermore, the tail portion has a third end and a fourth end that are disposed opposite to each other, the connecting portion connects the disc portion to the third end, and the length from the fourth end to the third end ranges from 2mm to 4mm.

[0014] Furthermore, a welding point for welding to the bottom cover plate is provided between the third end and the fourth end, and the distance between the welding point and the central axis of the bottom cover plate is in the range of 2mm to 6mm.

[0015] Furthermore, the height between the tail section and the disc section ranges from 1mm to 4mm.

[0016] The positive electrode current collector welding structure proposed in this utility model has the following beneficial effects:

[0017] (1) The positive electrode current collector of this welding structure includes a disk body, a tail body and a connecting part. The disk body, tail body and connecting part form a Z-shaped folding structure, and the included angle of the Z-shaped folding structure is 3° to 10°. This can reduce the space occupied in the battery casing, save the space in the battery casing, and reduce the pulling effect on the welding point to prevent the battery from breaking the circuit.

[0018] (2) This welding structure flattens the tops of multiple positive electrode tabs of the battery cell on the same horizontal plane to form a flattened layer. Therefore, by welding the disk body to the flattened layer, the positive current collector can be welded to multiple positive electrode tabs of the battery cell at the same time. This makes the welding of the positive current collector to multiple positive electrode tabs of the battery cell simple, convenient and easy to implement, thus making the practicality of this welding structure stronger.

[0019] (3) The disk body of this welding structure has a first end and a second end that are arranged opposite to each other. The length range from the first end to the second end is set to 12mm to 16mm. This ensures the welding area between the disk body and the flattened layer of the positive electrode tab of the battery cell, making the welding between the disk body and the positive electrode tab of the battery cell easier to implement. It also ensures the current carrying capacity after the disk body and the flattened layer are welded, and prevents the edges on both sides of the disk body from contacting the inner wall of the battery casing and causing a short circuit.

[0020] (4) The distance between the first end and the inner wall of the battery casing is set to 1mm to 3.5mm. By controlling the distance between the first end and the inner wall of the battery casing, the distance between the first end and the edge of the flattened layer is indirectly controlled, so as to prevent the burrs of the first end from puncturing the insulating tape and ensure that the insulating tape can extend to the first end.

[0021] (5) The distance between the second end and the inner wall of the battery casing is set to 3mm to 10mm in this welding structure. Under the premise of ensuring the distance between the first end and the edge of the flattened layer, and the length between the first end and the second end, the distance between the second end and the inner wall of the battery casing is prevented from being too small, which may cause the edge of the disc to touch the inner wall of the battery casing and cause a short circuit.

[0022] (6) The tail section of this welded structure has a third end and a fourth end that are arranged opposite to each other. The length range from the fourth end to the third end is set to 2mm to 4mm, so as to prevent the edge of the tail section from blocking the center of the bottom cover plate and affecting the outward flipping action of the explosion-proof sheet, and to ensure the welding area between the tail section and the bottom cover plate, thus ensuring the current carrying capacity of the positive electrode current collector.

[0023] (7) A welding point is provided at the middle position between the third end and the fourth end of this welding structure. The distance between the welding point and the central axis of the bottom cover plate is set to 2mm to 6mm. This prevents the angle of the Z-shaped folding structure formed by the disc body, tail body and connecting part from being too small, which may cause the disc body and tail body to partially overlap with the connecting part, affecting the overcurrent of the positive electrode current collector. It also prevents the edge of the tail body from blocking the center of the bottom cover plate, affecting the outward flipping action of the explosion-proof sheet.

[0024] (8) The height between the tail section and the disc section of this welding structure is 1mm to 4mm. The disc section and the tail section overlap with the connecting part, which affects the overcurrent of the positive electrode current collector and reduces the space occupied in the battery casing, saving space in the battery casing and facilitating the integration of large-capacity batteries. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements.

[0026] Figure 1 This is a schematic diagram of the installation of a positive electrode current collector welding structure in a battery casing according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram showing the unfolded positive current collector of a positive current collector welding structure according to an embodiment of the present utility model;

[0028] Figure 3 This is a schematic diagram of the cap of a positive current collector welding structure according to an embodiment of the present utility model.

[0029] In the diagram: 1. Battery casing; 11. Slot; 2. Battery cell; 21. Positive electrode tab; 22. Flattened layer; 3. Cap; 31. Top cover plate; 32. Explosion-proof sheet; 33. Isolation ring; 34. Bottom cover plate; 4. Positive current collector; 41. Disk body; 42. Tail body; 43. Connecting part. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0031] Please see Figures 1-3 A positive current collector welding structure according to an embodiment of the present invention includes a battery cell 2 disposed in a battery casing 1, a cap 3 fixedly connected to the battery casing 1, and a positive current collector 4 that conducts the positive electrode of the battery cell 2 to the cap 3; the positive current collector 4 includes a disk body portion 41 welded to the positive electrode tab 21 of the battery cell 2, a tail body portion 42 welded to the inner side of the cap 3, and a connecting portion 43 connecting the disk body portion 41 and the tail body portion 42. The disk body portion 41, the tail body portion 42 and the connecting portion 43 are an integral structure; the disk body portion 41, the tail body portion 42 and the connecting portion 43 form a Z-shaped folding structure, and the included angle of the Z-shaped folding structure is 3° to 10°.

[0032] In this application, the positive current collector 4 welding structure includes a battery cell 2, a cap 3, and a positive current collector 4. The battery cell 2 is disposed inside the battery casing 1. The cap 3 is closed and connected to the slot 11 of the casing. One end of the positive current collector 4 is welded to the positive electrode tab 21 of the battery cell 2, and the other end is welded to the inner side of the cap 3 (located on the side inside the casing). Thus, the positive electrode of the battery cell 2 is connected to the cap 3 through the positive current collector 4, and the positive electrode of the battery cell 2 is led out through the cap 3 to realize the charging and discharging function of the battery.

[0033] Specifically, in this embodiment, the positive current collector 4 includes a plate body 41, a tail body 42, and a connecting part 43. The plate body 41 is welded to the positive electrode tab 21 of the battery cell 2, the tail body 42 is welded to the inner side of the cap 3, and one end of the connecting part 43 is connected to the plate body 41 and the other end is connected to the tail body 42. Thus, the plate body 41 and the tail body 42 are connected through the connecting part 43, so that the plate body 41, the tail body 42, and the connecting part 43 conduct electricity between the tab of the battery cell 2 and the cap 3, thereby realizing that the positive current collector 4 conducts electricity between the positive electrode of the battery cell 2 and the cap 3.

[0034] In this embodiment, the disk body 41, tail body 42, and connecting part 43 are configured as an integral structure, that is, the positive electrode current collector 4 is manufactured by integral molding, thereby enhancing the structural strength of the positive electrode current collector 4 and thus enhancing the strength of this welded structure. It is foreseeable that in actual implementation, the battery assembly will first involve welding the disk body 41 and tail body 42 to the electrode tabs of the battery cell 2 and the inner side of the cap 3, respectively, then placing the battery cell 2 into the battery casing 1, and finally sealing the cap 3 to the slot 11 of the battery casing 1.

[0035] In the prior art, the positive current collector 4 is usually folded in a C-shape between the positive electrode tab 21 and the cap 3 of the cell 2. On the one hand, it occupies a lot of space in the battery casing 1, which is not conducive to the integration of large-capacity batteries. On the other hand, during the battery assembly process, when the cap 3 is closed and connected to the slot 11 of the battery casing 1, it is easy to cause a large pull on the solder joint of the positive current collector 4, which may cause the solder joint of the positive current collector 4 to be broken, thereby causing the battery to be open circuit.

[0036] In this application, the disk portion 41, the tail portion 42, and the connecting portion 43 form a Z-shaped folded structure. That is, in this application, the positive electrode current collector 4 is folded in a Z-shape between the positive electrode tab 21 and the cap 3 of the cell 2. On the one hand, this reduces the space occupied inside the battery casing 1, saves space inside the battery casing 1, and is conducive to the integration of large-capacity batteries. On the other hand, during the battery assembly process, when the cap 3 is closed and connected to the slot 11 of the battery casing 1, the pulling effect on the solder joint can be reduced, preventing the battery from being open-circuited, thereby ensuring the performance of the battery.

[0037] Furthermore, in this embodiment, the Z-shaped folding structure formed by the disk body 41, the tail body 42, and the connecting part 43 has an included angle α of 3° to 10°. That is, the included angle α of the Z-shaped folding of the positive current collector 4 between the positive electrode tab 21 and the cap 3 of the cell 2 is 3° to 10°. The reason for setting the included angle α of the Z-shaped folding of the positive current collector 4 to 3° to 10° is that if the included angle is too small, the disk body 41 and the tail body 42 may partially overlap with the connecting part 43, thereby affecting the current flow of the positive current collector 4.

[0038] However, if the included angle is too large, it will result in an excessively high overall height of the positive electrode current collector 4, wasting space within the battery casing 1 and hindering the integration of large-capacity batteries. In this application, a Z-shaped folding structure formed by the disk body 41, the tail body 42, and the connecting part 43 is preferred, with an included angle α of 5°.

[0039] In practice, a battery cell 2 typically has multiple positive electrode tabs 21 and a corresponding number of negative electrode tabs. Therefore, when the positive current collector 4 connects the positive electrode of the battery cell 2 to the cap 3, it needs to be soldered to the multiple positive electrode tabs 21 of the battery cell 2 simultaneously. Usually, the multiple positive electrode tabs 21 of the battery cell 2 are relatively dispersed, which makes soldering the positive current collector 4 to the multiple positive electrode tabs 21 of the battery cell 2 difficult.

[0040] In this embodiment, the tops of the multiple positive electrode tabs 21 of the battery cell 2 are mechanically flattened to form a flattened layer 22 on the same horizontal plane. Therefore, the positive current collector 4 is welded to the flattened layer 22, so that the positive current collector 4 can be welded to the multiple positive electrode tabs 21 of the battery cell 2 at the same time. This makes the welding of the positive current collector 4 to the multiple positive electrode tabs 21 of the battery cell 2 simple, convenient and easy to implement, thereby making the practicality of this welding structure stronger.

[0041] In this embodiment, the cap 3 includes a top cover plate 31, an explosion-proof sheet 32, an isolation ring 33, and a bottom cover plate 34 arranged sequentially from the outside to the inside. The central axes of the top cover plate 31, the explosion-proof sheet 32, the isolation ring 33, and the bottom cover plate 34 are on the same straight line, and the tail body 42 is welded to the bottom cover plate 34.

[0042] In this application, the cap 3 includes a top cover plate 31, an explosion-proof sheet 32, an isolation ring 33, and a bottom cover plate 34. The top cover plate 31, the explosion-proof sheet 32, the isolation ring 33, and the bottom cover plate 34 are arranged sequentially from the outside to the inside. The bottom cover plate 34 is used to weld to the tail body 42. The isolation ring 33 is disposed between the bottom cover plate 34 and the explosion-proof sheet 32. The center part of the bottom cover plate 34 is fixedly connected to the center part of the explosion-proof sheet 32 ​​through the through hole of the isolation ring 33. The periphery of the bottom cover plate 34 is separated from the explosion-proof sheet 32 ​​by the isolation ring 33.

[0043] The explosion-proof plate 32 and the top cover plate 31 are sealed to the slot 11 of the battery casing 1. When the battery experiences thermal runaway, the pressure inside the battery casing 1 increases, which in turn acts on the center of the explosion-proof plate 32 through the center of the bottom cover plate 34, causing the explosion-proof plate 32 to flip outward, thereby relieving pressure inside the battery casing 1 and ensuring the battery's safety performance. The top of the top cover plate 31 is exposed on the battery casing 1, allowing the positive terminal of the battery cell 2 to be led out through the top cover plate 31, realizing the battery's charging and discharging function.

[0044] In this embodiment, the disc portion 41 has a first end and a second end that are disposed opposite to each other. The connecting portion 43 connects the second end of the disc portion 41 to the tail portion 42, thereby forming a Z-shaped folding structure with the disc portion 41, the connecting portion 43 and the tail portion 42. This not only reduces the space occupied inside the battery housing 1 and saves space inside the battery housing 1, which is beneficial for the integration of large-capacity batteries, but also reduces the pulling effect on the solder joints when the cap 3 is closed and connected to the slot 11 of the battery housing 1 during the battery assembly process, preventing the battery from being open-circuited, thereby ensuring the performance of the battery.

[0045] Specifically, since the first end and the second end are the two opposite ends of the disc body 41, that is, the first end and the second end are the edges on both sides of the disc body 41, and the disc body 41 is welded to the flattened layer 22 of the positive electrode tab 21 of the battery cell 2 through the area between the first end and the second end.

[0046] If the length from the first end to the second end of the disc portion 41 is too large, when the disc portion 41 is placed inside the battery casing 1, the edges on both sides of the disc portion 41 may touch the inner wall of the battery casing 1, thereby causing a short circuit in the battery; if the length from the first end to the second end of the disc portion 41 is too small, it will affect the welding area between the disc portion 41 and the flattening layer 22, thereby affecting the current carrying capacity of the positive electrode current collector 4.

[0047] Therefore, in this application, the length L1 from the first end to the second end is set to a range of 12mm to 16mm. This ensures sufficient welding area between the disc body 41 and the flattened layer 22 of the positive electrode tab 21 of the battery cell 2, making welding between the disc body 41 and the positive electrode tab 21 of the battery cell 2 easier to implement, while also ensuring the current carrying capacity after welding the disc body 41 and the flattened layer 22. Furthermore, it prevents the edges on both sides of the disc body 41 from contacting the inner wall of the battery casing 1 and causing a short circuit. Preferably, in this embodiment, the length L1 from the first end to the second end is set to 14.55mm.

[0048] In actual implementation, after the disc body 41 is welded to the flattening layer 22, it is usually necessary to wrap insulating tape around the outer periphery of the flattening layer 22, while extending the insulating tape to the disc body 41, so as to provide insulation through the insulating tape and prevent the disc body 41 and the flattening layer 22 from contacting the inner wall of the battery casing 1 and causing a short circuit.

[0049] Therefore, in this embodiment, the first end of the disc body 41 is brought close to the edge of the leveling layer 22, so that the insulating tape wrapped around the outer periphery of the leveling layer 22 can extend to the first end of the disc body 41 and cover the first end of the disc body 41. Since there are burrs on the edge of the disc body 41, when the insulating tape covers the first end of the disc body 41, if the distance between the first end and the edge of the leveling layer 22 is too close, the burrs at the first end may puncture the insulating tape, thereby causing the insulating tape to fail to provide insulation. If the first end is too far from the edge of the leveling layer 22, the insulating tape wrapped around the outer periphery of the leveling layer 22 may not be able to extend to the first end of the disc body 41.

[0050] In this application, since the flattened layer 22 of the positive electrode tab 21 of the battery cell 2 has an irregular shape, the distance between the first end of the disc portion 41 and the inner wall of the battery casing 1 is indirectly controlled by measuring the distance between the first end and the edge of the flattened layer 22. Specifically, the distance L2 between the first end and the inner wall of the battery casing 1 is set to a range of 1mm to 3.5mm, thereby preventing the burrs at the first end from puncturing the insulating tape while ensuring that the insulating tape can extend to the first end. Preferably, in this embodiment, the distance L2 between the first end and the inner wall of the battery casing 1 is set to 1.5mm.

[0051] Furthermore, in this embodiment, the distance L3 between the second end and the inner wall of the battery casing 1 is set to a range of 3mm to 10mm. This ensures the distance between the first end and the edge of the flattened layer 22, as well as the lengths of the first and second ends, while preventing the distance between the second end and the inner wall of the battery casing 1 from being too small, which could cause the edge of the disc portion 41 to potentially contact the inner wall of the battery casing 1 and cause a short circuit. Preferably, in this embodiment, the distance L3 between the second end and the inner wall of the battery casing 1 is set to 5.6mm.

[0052] In this embodiment, the tail section 42 is welded to the bottom cover plate 34 at a position off-center from the central axis. As mentioned in the previous embodiment, the central part of the bottom cover plate 34 is fixedly connected to the central part of the explosion-proof sheet 32 ​​through the through hole of the isolation ring 33. When the battery experiences thermal runaway, the central part of the bottom cover plate 34 acts on the central part of the explosion-proof sheet 32, causing the explosion-proof sheet 32 ​​to flip outward, thereby relieving pressure inside the battery casing 1 and ensuring the safety performance of the battery.

[0053] Therefore, in this application, when welding the tail portion 42 to the inner side of the bottom cover plate 34, the tail portion 42 and the bottom cover plate 34 are welded at a position off the central axis, so as to prevent the tail portion 42 of the bottom cover plate 34 from being welded to block the central part of the bottom cover plate 34, thereby affecting the outward flipping action of the explosion-proof sheet 32 ​​and ensuring the function of the explosion-proof sheet 32 ​​to relieve pressure inside the battery casing 1.

[0054] In this embodiment, the tail portion 42 has a third end and a fourth end that are arranged opposite to each other. The connecting portion 43 connects the second end of the disc portion 41 to the third end of the tail portion 42. The first end of the disc portion 41 and the fourth end of the tail portion 42 extend in opposite directions on both sides of the connecting portion 43. This Z-shaped folding structure formed by the disc portion 41, the connecting portion 43 and the tail portion 42 reduces the space occupied in the housing, saves space in the housing, and is conducive to the integration of large-capacity batteries. In addition, during the battery assembly process, when the cap 3 is closed and connected to the slot 11 of the housing, the pulling effect on the solder joint can be reduced, preventing the battery from breaking the circuit, thereby ensuring the performance of the battery.

[0055] Specifically, since the third and fourth ends are the opposite ends of the tail section 42, that is, the third and fourth ends are the edges on both sides of the tail section 42, and the tail section 42 is welded to the inner side of the bottom cover plate 34 off the central axis through the area between the third and fourth ends. If the length of the third and fourth ends of the tail section 42 is too large, there is still a possibility that the edge of the tail section 42 will block the center of the bottom cover plate 34, thus affecting the outward flipping action of the explosion-proof plate 32; if the length of the third and fourth ends of the tail section 42 is too small, it will affect the welding area between the tail section 42 and the bottom cover plate 34, thus affecting the current carrying capacity of the positive current collector 4.

[0056] Therefore, in this application, the length L4 from the fourth end to the third end is set to a range of 2mm to 4mm, thereby preventing the edge of the tail portion 42 from obstructing the center of the bottom cover plate 34, while ensuring the welding area between the tail portion 42 and the bottom cover plate 34, thus guaranteeing the current carrying capacity of the positive electrode current collector 4. Preferably, in this embodiment, the length L4 from the fourth end to the third end is set to 3mm.

[0057] Furthermore, in this embodiment, a welding point is provided at the middle position between the third end and the fourth end. The third end and the fourth end are the two opposite ends of the tail body 42, that is, a welding point is provided at the center position of the tail body 42, so that the tail body 42 is welded to the inner side of the bottom cover plate 34 through the welding point, and the distance from the welding point to the third end or the fourth end is equal to half the length from the fourth end to the third end.

[0058] As mentioned in the preceding embodiments, the tail section 42 is welded to the inner side of the bottom cover plate 34 at a position offset from the central axis. Therefore, to prevent the edge of the tail section 42 from obstructing the center of the bottom cover plate 34, the distance between the weld point and the central axis of the bottom cover plate 34 needs to be greater than or equal to half the length from the fourth end to the third end. The length from the fourth end to the third end ranges from 2mm to 4mm. Therefore, in this application, the distance between the weld point and the central axis of the bottom cover plate 34 needs to be greater than or equal to 2mm.

[0059] However, if the distance between the solder joint and the central axis of the bottom cover plate 34 is too large, the angle of the Z-shaped folding structure formed by the disc body 41, the tail body 42, and the connecting part 43 will be too small. This could lead to partial overlap between the disc body 41 and the tail body 42 and the connecting part 43, affecting the current flow of the positive current collector 4. Therefore, in this application, the distance L5 between the solder joint and the central axis of the bottom cover plate 34 is set to 2mm to 6mm. Preferably, in this embodiment, the distance L5 between the solder joint and the central axis of the bottom cover plate 34 is set to 3.2mm.

[0060] In actual implementation, when the disk body 41, tail body 42 and connecting part 43 form a Z-shaped folding structure, if the height difference between the disk body 41 and tail body 42 is too small, it may cause the disk body 41 and tail body 42 to partially overlap with the connecting part 43, affecting the overcurrent of the positive electrode current collector 4; while if the height difference between the disk body 41 and tail body 42 is too large, it will cause the overall height of the positive electrode current collector 4 to be too high, wasting the space inside the battery casing 1, which is not conducive to the integration of large-capacity batteries.

[0061] Therefore, in this embodiment, the height H between the tail portion 42 and the disk portion 41 is in the range of 1mm to 4mm. This means that the disk portion 41 and the tail portion 42 partially overlap with the connecting portion 43, affecting the current flow of the positive electrode current collector 4, while also reducing the space occupied within the battery casing 1, thus saving space and facilitating the integration of large-capacity batteries. Preferably, in this embodiment, the height H between the tail portion 42 and the disk portion 41 is set to 3mm.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A positive electrode current collector welding structure, characterized in that: The battery includes a battery cell (2) disposed in a battery casing (1), a cap (3) fixedly connected to the battery casing (1), and a positive current collector (4) that connects the positive electrode of the battery cell (2) to the cap (3). The positive current collector (4) includes a disk body (41) welded to the positive electrode tab (21) of the battery cell (2), a tail body (42) welded to the inside of the cap (3), and a connecting part (43) connecting the disk body (41) and the tail body (42). The disk body (41), the tail body (42) and the connecting part (43) are an integral structure. The disk body (41), the tail body (42) and the connecting part (43) form a Z-shaped folding structure with an included angle of 3° to 10°.

2. The positive electrode current collector welding structure as described in claim 1, characterized in that: The tops of the multiple positive electrode tabs (21) of the battery cell (2) are flattened on the same horizontal plane to form a flattened layer (22), and the disk body (41) is welded to the flattened layer (22).

3. The positive electrode current collector welding structure as described in claim 1, characterized in that: The cap (3) includes a top cover plate (31), an explosion-proof sheet (32), an isolation ring (33), and a bottom cover plate (34) arranged sequentially from the outside to the inside. The central axes of the top cover plate (31), the explosion-proof sheet (32), the isolation ring (33), and the bottom cover plate (34) are on the same straight line. The tail body (42) is welded to the bottom cover plate (34).

4. The positive electrode current collector welding structure as described in claim 1, characterized in that: The disc body (41) has a first end and a second end that are disposed opposite to each other. The connecting part (43) connects the second end to the tail body (42). The length from the first end to the second end is 12mm to 16mm.

5. The positive electrode current collector welding structure as described in claim 4, characterized in that: The distance between the first end and the inner wall of the battery casing (1) ranges from 1 mm to 3.5 mm.

6. The positive electrode current collector welding structure as described in claim 5, characterized in that: The distance between the second end and the inner wall of the battery casing (1) is 3mm to 10mm.

7. The positive electrode current collector welding structure as described in claim 3, characterized in that: The tail section (42) is welded to the bottom cover plate (34) at a position off the central axis.

8. The positive electrode current collector welding structure as described in claim 7, characterized in that: The tail section (42) has a third end and a fourth end that are disposed opposite to each other. The connecting part (43) connects the disc section (41) to the third end. The length of the fourth end to the third end is 2mm to 4mm.

9. The positive electrode current collector welding structure as described in claim 8, characterized in that: A welding point is provided at the midpoint between the third end and the fourth end for welding to the bottom cover plate (34). The distance between the welding point and the central axis of the bottom cover plate (34) is in the range of 2mm to 6mm.

10. The positive electrode current collector welding structure as described in claim 1, characterized in that: The height between the tail section (42) and the disc section (41) ranges from 1 mm to 4 mm.

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