A cylindrical secondary battery

Abstract

The utility model relates to a kind of cylindrical secondary batteries.It relates to the technical field of new energy battery.The specific application includes the ratio L0 / R0 of the length L0 of positive electrode weld mark and the radius R0 of disc body is 42.9%~56%, the ratio W0 / R0 of the width W0 of positive electrode weld mark and the radius R0 of disc body is 26.4%~35.2%, the ratio L1 / R1 of the length L1 of negative electrode weld mark and the radius R1 of negative electrode current collector is 37%~57%, and the ratio W1 / R1 of the width W1 of negative electrode weld mark and the radius R1 of negative electrode current collector is 17%~36%.The utility model sets L0 / R0 to 42.9%~56%, W0 / R0 to 26.4%~35.2%, L1 / R1 to 37%~57%, and W1 / R1 to 17%~36%, to prevent the size of positive electrode weld mark and negative electrode weld mark from being too small or too large, thereby ensuring the connection strength of positive electrode current collector and positive electrode tab of roll core, reducing the risk of poor welding, improving the welding efficiency of positive electrode current collector and positive electrode tab of roll core, and further ensuring the performance of cylindrical secondary batteries, improving the production efficiency of cylindrical secondary batteries.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a cylindrical secondary battery. Background Technology

[0002] Cylindrical secondary batteries are widely used in various fields, including mobile devices, electric vehicles, energy storage systems, and consumer electronics, due to their advantages such as high energy density, good heat dissipation, good mechanical strength, ease of manufacturing, and wide range of applications. A typical cylindrical secondary battery includes a battery casing, a core housed within the casing, a positive current collector on top of the core, a negative current collector on top of the core, and a cap assembly that seals the top opening of the battery casing.

[0003] The positive current collector and the positive terminal tab of the winding core are welded together by positive electrode soldering, which connects the positive terminal tab of the winding core to the cap assembly, thereby allowing the cap assembly to lead out the positive electrode of the winding core. The negative current collector and the negative terminal tab of the winding core are welded together by negative electrode soldering, which connects the negative terminal tab of the winding core to the battery casing, thereby allowing the battery casing to lead out the negative electrode of the winding core, thus realizing the charging and discharging function of the cylindrical secondary battery.

[0004] In existing technologies, the design of the positive and negative electrode solder marks in cylindrical secondary batteries is not entirely reasonable. In some cylindrical secondary batteries, the dimensions of the positive and negative electrode solder marks are designed to be too small. This not only leads to insufficient connection strength between the positive and negative current collectors and the core, affecting the stability of the cylindrical secondary battery structure, but also causes concentrated heat generation at the solder marks during the welding process, making it prone to burn-through, explosions, and other issues, thus affecting the performance of the cylindrical secondary battery.

[0005] Some cylindrical secondary batteries have excessively large positive and negative electrode solder marks, which not only increases the stroke of the welding equipment and reduces welding efficiency, thus affecting the production efficiency of cylindrical secondary batteries, but also increases the risk of welding defects, thereby affecting the performance of cylindrical secondary batteries. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a cylindrical secondary battery that can ensure the connection strength between the positive and negative current collectors and the core, reduce the risk of poor welding, and improve the welding efficiency between the positive and negative current collectors and the core, thereby ensuring the performance of the cylindrical secondary battery and improving its production efficiency.

[0007] This utility model proposes a cylindrical secondary battery, including a core, a positive current collector, and a negative current collector. The positive current collector includes a disk body, which is connected to the positive terminal tab of the core via a positive electrode solder joint. The negative current collector is connected to the negative terminal tab of the core via a negative electrode solder joint. The ratio of the length L0 of the positive electrode solder joint to the radius R0 of the disk body (L0 / R0) is 42.9%–56%, the ratio of the width W0 of the positive electrode solder joint to the radius R0 of the disk body (W0 / R0) is 26.4%–35.2%, the ratio of the length L1 of the negative electrode solder joint to the radius R1 of the negative current collector (L1 / R1) is 37%–57%, and the ratio of the width W1 of the negative electrode solder joint to the radius R1 of the negative current collector (W1 / R1) is 17%–36%.

[0008] Furthermore, the length L0 of the positive electrode solder mark ranges from 3.9 mm to 5.1 mm, and the width W0 of the positive electrode solder mark ranges from 2.4 mm to 3.2 mm.

[0009] Furthermore, the length L1 of the negative electrode solder mark ranges from 3.5mm to 5.5mm, and the width W1 of the negative electrode solder mark ranges from 1.6mm to 3.4mm.

[0010] Furthermore, the positive electrode solder mark includes multiple positive electrode solder lines arranged circumferentially around the central axis of the disk body, and the width W01 of each positive electrode solder line ranges from 0.2mm to 0.4mm.

[0011] Furthermore, the positive electrode bonding wire is corrugated, and the included angle A of each corrugation of the positive electrode bonding wire ranges from 10° to 30°.

[0012] Furthermore, the negative electrode solder marks are multiple ones arranged circumferentially around the central axis of the negative electrode current collector, and each negative electrode solder mark includes multiple negative electrode welding lines arranged in parallel and spaced apart, with the distance W10 between two adjacent negative electrode welding lines ranging from 0.6mm to 1.1mm.

[0013] Furthermore, the width W11 of each of the negative electrode bonding wires ranges from 0.1 mm to 0.3 mm.

[0014] Furthermore, the negative electrode bonding wire is corrugated, and the internal protrusion height W12 of each negative electrode bonding wire ranges from 0.15mm to 0.35mm.

[0015] Furthermore, the included angle B of each corrugation of the negative electrode bonding wire ranges from 70° to 120°.

[0016] Furthermore, the radius R0 of the disk body ranges from 8.8mm to 9.4mm, and the radius R1 of the negative electrode current collector ranges from 8.5mm to 10.5mm.

[0017] The cylindrical secondary battery proposed in this utility model has the following beneficial effects:

[0018] (1) The ratio of the length L0 of the positive electrode soldering to the radius R0 of the disk body is set between 42.9% and 56%, and the ratio of the width W0 of the positive electrode soldering to the radius R0 of the disk body is set between 26.4% and 35.2%. This prevents the size of the positive electrode soldering from being too small or too large, ensuring the connection strength between the positive electrode current collector and the positive terminal tab of the core, reducing the risk of poor welding, and improving the welding efficiency between the positive electrode current collector and the positive terminal tab of the core. This ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0019] (2) The ratio of the length L1 of the negative electrode solder mark to the radius R1 of the negative electrode current collector is set between 37% and 57%, and the ratio of the width W1 of the negative electrode solder mark to the radius R1 of the negative electrode current collector is set between 17% and 36%. This prevents the size of the negative electrode solder mark from being too small or too large, ensuring the connection strength between the negative electrode current collector and the negative terminal tab of the core, reducing the risk of poor welding, and improving the welding efficiency between the negative electrode current collector and the negative terminal tab of the core. This ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0020] (3) The length L0 of the positive electrode solder mark is set to 3.9mm to 5.1mm and the width W0 of the positive electrode solder mark is set to 2.4mm to 3.2mm. This prevents the size of the positive electrode solder mark from being too small or too large, ensuring the connection strength between the positive electrode current collector and the positive electrode tab of the core, reducing the risk of poor welding, and improving the welding efficiency between the positive electrode current collector and the positive electrode tab of the core. This ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0021] (4) The length L1 of the negative electrode solder mark is set to 3.5mm to 5.5mm and the width W1 of the negative electrode solder mark is set to 1.6mm to 3.4mm. This prevents the size of the negative electrode solder mark from being too small or too large. This ensures the connection strength between the negative electrode current collector and the negative electrode tab of the core, reduces the risk of poor welding, and improves the welding efficiency between the negative electrode current collector and the negative electrode tab of the core. This ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0022] (5) The width W01 of each positive electrode welding line in this battery is set between 0.2mm and 0.4mm to prevent the width W01 of the positive electrode welding line from being too small or too large. This ensures both the current carrying capacity of the positive electrode current collector and prevents the heat at the positive electrode welding line from being too high, which could lead to welding burn-through, explosion, etc., thereby ensuring the performance of the cylindrical secondary battery.

[0023] (6) The included angle A of each corrugation of the positive electrode welding wire is set between 10° and 30° in this battery, so as to prevent the included angle A of each corrugation of the positive electrode welding wire from being too small or too large. This prevents the heat at the positive electrode welding wire from being excessively concentrated during welding, and ensures the current carrying capacity of the positive electrode current collector and the connection strength between the positive electrode current collector and the positive terminal tab of the core, thereby ensuring the performance of the cylindrical secondary battery.

[0024] (7) The distance W10 between two adjacent negative electrode welding lines is set to 0.6mm to 1.1mm to prevent the distance W10 between two adjacent negative electrode welding lines from being too close or too far. This prevents the heat at the negative electrode welding point from being excessively concentrated during welding and reduces the travel of the welding equipment when switching between two adjacent negative electrode welding lines, thereby ensuring the performance of the cylindrical secondary battery and improving the production efficiency of the cylindrical secondary battery.

[0025] (8) The width W11 of each negative electrode welding line in this battery is set to be 0.1mm to 0.3mm. This prevents the width W11 of each negative electrode welding line from being too small or too large, thereby ensuring the current carrying capacity of the negative electrode current collector and the connection strength with the negative electrode tab of the core, and preventing the heat at the negative electrode welding line from being too high, which could lead to welding burn-through, explosion, etc., thus ensuring the performance of the cylindrical secondary battery.

[0026] (9) The internal protrusion height W12 of each negative electrode welding wire is set to 0.15mm to 0.35mm to prevent the fluctuation range of each ripple of the negative electrode welding wire from being too small or too large. This prevents the heat at the negative electrode welding point from being excessively concentrated during welding and reduces the stroke of the welding equipment on a single negative electrode welding wire, thereby ensuring the performance of the cylindrical secondary battery and improving the production efficiency of the cylindrical secondary battery.

[0027] (10) The included angle B of each corrugation of the negative electrode welding wire is set between 70° and 120° in this battery, so as to prevent the included angle B of each corrugation of the negative electrode welding wire from being too small or too large. This prevents the heat at the negative electrode welding wire from being excessively concentrated during welding, and ensures the current carrying capacity of the negative electrode current collector and the connection strength between the negative electrode current collector and the negative terminal tab of the core, thereby ensuring the performance of the cylindrical secondary battery. Attached Figure Description

[0028] 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.

[0029] Figure 1 This is a planar schematic diagram showing the positive electrode current collector and the positive electrode tab of the winding core connected by positive electrode soldering in an embodiment of the present utility model.

[0030] Figure 2 This is a planar schematic diagram of the connection between the negative electrode current collector and the negative electrode tab of the winding core in an embodiment of the present utility model.

[0031] Figure 3 for Figure 1 Enlarged view of point C in the middle;

[0032] Figure 4 for Figure 2 Enlarged diagram of point D in the middle.

[0033] In the diagram: 1. Core; 2. Positive current collector; 21. Disc body; 22. Tail body; 3. Negative current collector; 4. Positive solder mark; 41. Positive solder wire; 5. Negative solder mark; 51. Negative solder wire. Detailed Implementation

[0034] 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.

[0035] Please see Figures 1-4 A cylindrical secondary battery according to an embodiment of the present invention includes a core 1, a positive current collector 2 and a negative current collector 3. The positive current collector 2 includes a disk body 21 and a tail body 22. When the tail body 22 is unfolded, one end is connected to the disk body 21 and the other end extends away from the disk body 21. When the tail body 22 is bent, the end extending away from the disk body 21 is located above the disk body 21 and is parallel to the disk body 21.

[0036] The disc 21 is welded to the positive terminal lug of the core 1 via the positive electrode solder mark 4, thereby connecting the positive current collector 2 to the positive terminal lug of the core 1; the tail 22 is welded to the lower end plate of the cap assembly, thereby connecting the positive current collector 2 to the cap assembly. The positive current collector 2 is used for connection and current flow, allowing the cap assembly to lead out the positive electrode of the core 1.

[0037] The negative electrode current collector 3 is welded to the negative electrode tab of the core 1 through the negative electrode solder mark 5 and connected to the battery casing. Thus, the negative electrode current collector 3 is used for connection and current flow, allowing the battery casing to lead out the negative electrode of the core 1, thereby realizing the charging and discharging function of the cylindrical secondary battery.

[0038] In practical use, if the size of the positive electrode solder mark 4 and the negative electrode solder mark 5 is designed to be too small, it will not only lead to insufficient connection strength between the positive electrode current collector 2 and the negative electrode current collector 3 and the core 1, affecting the stability of the cylindrical secondary battery structure, but also cause the heat to be concentrated at the solder mark during the welding process, which can easily lead to weld burn-through, explosion and other problems, affecting the performance of the cylindrical secondary battery.

[0039] If the dimensions of the positive electrode solder mark 4 and the negative electrode solder mark 5 are designed to be too large, it will not only increase the stroke of the welding equipment and reduce the welding efficiency, thus affecting the production efficiency of cylindrical secondary batteries, but also increase the risk of welding defects, thereby affecting the performance of cylindrical secondary batteries.

[0040] Therefore, in this application, the ratio of the length L0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21, L0 / R0, is set between 42.9% and 56%, and the ratio of the width W0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21, W0 / R0, is set between 26.4% and 35.2%. This prevents the size of the positive electrode solder mark 4 from being too small or too large, ensuring the connection strength between the positive electrode current collector 2 and the positive terminal tab of the core 1, reducing the risk of poor welding, and improving the welding efficiency between the positive electrode current collector 2 and the positive terminal tab of the core 1. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0041] The ratio L1 / R1 of the length L1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3 is set between 37% and 57%, and the ratio W1 / R1 of the width W1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3 is set between 17% and 36%. This prevents the size of the negative electrode solder mark 5 from being too small or too large, ensuring the connection strength between the negative electrode current collector 3 and the negative terminal tab of the core 1, reducing the risk of poor welding, and improving the welding efficiency between the negative electrode current collector 3 and the negative terminal tab of the core 1. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0042] In practical implementation, preferably, the ratio of the width W0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21, W0 / R0, is set to 49%, the ratio of the width W0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21, W0 / R0, is set to 31%, the ratio of the length L1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3, L1 / R1, is set to 47%, and the ratio of the width W1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3, W1 / R1, is set to 26%.

[0043] Specifically, in this embodiment, the length L0 of the positive electrode solder mark 4 is set to a range of 3.9mm to 5.1mm, and the width W0 of the positive electrode solder mark 4 is set to a range of 2.4mm to 3.2mm. This prevents the size of the positive electrode solder mark 4 from being too small or too large, ensuring the connection strength between the positive electrode current collector 2 and the positive terminal tab of the core 1, reducing the risk of poor welding, and improving the welding efficiency between the positive electrode current collector 2 and the positive terminal tab of the core 1. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0044] In practical implementation, preferably, the length L0 of the positive electrode solder mark 4 is set to 4.5mm and the width W0 of the positive electrode solder mark 4 is set to 2.8mm.

[0045] Specifically, in this embodiment, the length L1 of the negative electrode solder mark 5 is set to a range of 3.5mm to 5.5mm, and the width W1 of the negative electrode solder mark 5 is set to a range of 1.6mm to 3.4mm. This prevents the size of the negative electrode solder mark 5 from being too small or too large, ensuring the connection strength between the negative electrode current collector 3 and the negative terminal tab of the core 1, reducing the risk of poor welding, and improving the welding efficiency between the negative electrode current collector 3 and the negative terminal tab of the core 1. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery.

[0046] In actual implementation, preferably, the length L1 of the negative electrode solder mark 5 is set to 4.5mm and the width W1 of the negative electrode solder mark 5 is set to 2.5mm.

[0047] In this embodiment, the positive electrode solder mark 4 includes multiple positive electrode solder lines 41, which are arranged circumferentially around the central axis of the disk body 21. The disk body 21 and the positive electrode tab of the winding core 1 are welded through the multiple positive electrode solder lines 41, thereby enhancing the connection strength between the positive electrode current collector 2 and the winding core 1, and thus enhancing the stability of the cylindrical secondary battery structure and ensuring the performance of the cylindrical secondary battery.

[0048] In practical use, if the width W01 of each positive electrode welding wire 41 is designed to be too small, the welding area between the disc body 21 and the positive electrode tab of the core 1 will be reduced, thereby reducing the current carrying capacity of the positive electrode current collector 2 and affecting the performance of the cylindrical secondary battery. On the other hand, if the width W01 of each positive electrode welding wire 41 is designed to be too large, the heat at the positive electrode welding wire 41 will be too high during the welding process, which may easily lead to weld burn-through, explosion, and other problems, which will also affect the performance of the cylindrical secondary battery.

[0049] Therefore, in this application, the width W01 of each positive electrode bonding wire 41 is set between 0.2mm and 0.4mm to prevent the width W01 of the positive electrode bonding wire 41 from being too small or too large. This ensures both the current carrying capacity of the positive electrode current collector 2 and prevents excessive heat at the positive electrode bonding wire 41, which could lead to solder burn-through, explosion, or other issues, thereby guaranteeing the performance of the cylindrical secondary battery. In practical implementation, it is preferable to set the width W01 of each positive electrode bonding wire 41 to 0.3mm.

[0050] Furthermore, in this embodiment, the multiple positive electrode welding lines 41 are set as corrugated, thereby increasing the welding area between the disc body 21 and the positive terminal tab of the core 1 when the length L0 of the positive electrode welding mark 4 is limited. This not only enhances the current carrying capacity of the positive electrode current collector 2, but also enhances the connection strength between the disc body 21 and the positive terminal tab of the core 1, thereby ensuring the performance of the cylindrical secondary battery.

[0051] In practical use, if the included angle A of each corrugation of the positive electrode bonding wire 41 is designed to be too small, the number of corrugations of the positive electrode bonding wire 41 will increase when the length L0 of the positive electrode solder mark 4 is limited. This will result in the positive electrode bonding wire 41 being more dense, which will cause the heat at the positive electrode bonding wire 41 to be more concentrated during the welding process, making it easy for issues such as soldering through and explosion to occur, thus affecting the performance of the cylindrical secondary battery.

[0052] If the included angle A of each corrugation of the positive electrode bonding wire 41 is designed to be too large, the number of corrugations of the positive electrode bonding wire 41 will be reduced when the length L0 of the positive electrode bonding mark 4 is limited. This will result in a reduction in the length of each positive electrode bonding wire 41, thereby reducing the current carrying capacity of the positive electrode current collector 2 and the connection strength between the positive electrode current collector 2 and the positive terminal tab of the core 1, which in turn will affect the performance of the cylindrical secondary battery.

[0053] Therefore, in this application, the included angle A of each corrugation of the positive electrode bonding wire 41 is set between 10° and 30° to prevent the included angle A of each corrugation of the positive electrode bonding wire 41 from being too small or too large. This prevents excessive heat concentration at the positive electrode bonding wire 41 during welding, while ensuring the current carrying capacity of the positive electrode current collector 2 and the connection strength between the positive electrode current collector 2 and the positive terminal tab of the core 1, thereby ensuring the performance of the cylindrical secondary battery. In practical implementation, preferably, the included angle A of each corrugation of the positive electrode bonding wire 41 is set to 18°.

[0054] In this embodiment, there are multiple negative electrode solder marks 5 arranged circumferentially around the central axis of the negative electrode current collector 3, and each negative electrode solder mark 5 includes multiple negative electrode welding lines 51 arranged in parallel and spaced apart. Thus, the negative electrode current collector 3 and the negative electrode tab of the core 1 are welded through the multiple negative electrode welding lines 51 of the multiple negative electrode solder marks 5, which enhances the connection strength between the negative electrode current collector 3 and the core 1, thereby enhancing the stability of the cylindrical secondary battery structure and ensuring the performance of the cylindrical secondary battery.

[0055] In practical use, if the distance W10 between two adjacent negative electrode solder lines 51 is designed to be too small for the same negative electrode solder mark 5, the heat at the negative electrode solder mark 5 will be concentrated during welding, which may easily lead to solder burn-through, explosion, etc., thus affecting the performance of the cylindrical secondary battery.

[0056] However, if the distance W10 between two adjacent negative electrode welding lines 51 is designed to be too large, it will lead to a larger stroke of the welding equipment when switching between the two adjacent negative electrode welding lines 51 during welding, thereby reducing welding efficiency and affecting the production efficiency of cylindrical secondary batteries.

[0057] Therefore, in this application, the distance W10 between two adjacent negative electrode welding wires 51 is set to a range of 0.6mm to 1.1mm. This prevents the distance W10 between two adjacent negative electrode welding wires 51 from being too close or too far, thus preventing excessive heat concentration at the negative electrode solder mark 5 during welding and reducing the travel distance of the welding equipment when switching between two adjacent negative electrode welding wires 51. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery. In practical implementation, it is preferable to set the distance W10 between two adjacent negative electrode welding wires 51 to 0.85mm.

[0058] In practical use, if the width W11 of each negative electrode welding wire 51 is designed to be too small, it will affect the current carrying capacity of the negative electrode current collector 3 and reduce the connection strength between the negative electrode current collector 3 and the negative electrode tab of the core 1, thus affecting the performance of the cylindrical secondary battery. On the other hand, if the width W11 of each negative electrode welding wire 51 is designed to be too large, it will cause the heat at the negative electrode welding wire 51 to be too high during the welding process, which will easily lead to weld burn-through, explosion and other situations, which will also affect the performance of the cylindrical secondary battery.

[0059] Therefore, in this embodiment, the width W11 of each negative electrode bonding wire 51 is further set to a range of 0.1mm to 0.3mm. This prevents the width W11 of each negative electrode bonding wire 51 from being too small or too large, thereby ensuring both the current carrying capacity of the negative electrode current collector 3 and the connection strength with the negative electrode tab of the winding core 1, while also preventing excessive heat at the negative electrode bonding wire 51, which could lead to solder burn-through, explosion, or other issues, thus ensuring the performance of the cylindrical secondary battery. In practical implementation, preferably, the width W11 of each negative electrode bonding wire 51 is set to 0.2mm.

[0060] In this embodiment, multiple negative electrode welding lines 51 are set in a corrugated shape, thereby increasing the welding area between the negative electrode current collector 3 and the negative electrode tab of the core 1 when the length L1 of the negative electrode welding mark 5 is limited. This enhances both the current carrying capacity of the negative electrode current collector 3 and the connection strength between the negative electrode current collector 3 and the negative electrode tab of the core 1, thus ensuring the performance of the cylindrical secondary battery.

[0061] In actual use, if the internal protrusion height W12 of each negative electrode welding wire 51 is designed to be too small, that is, the fluctuation range of each corrugation of the negative electrode welding wire 51 is small, the heat at the negative electrode welding wire 51 will be concentrated during welding, which will easily lead to weld burn-through, explosion and other situations. It will also affect the current carrying capacity of the negative electrode current collector 3 and the connection strength with the negative terminal tab of the core 1, thus affecting the performance of the cylindrical secondary battery.

[0062] However, if the internal protrusion height W12 of each negative electrode welding wire 51 is designed to be too large, that is, the fluctuation range of each ripple of the negative electrode welding wire 51 is large, it will increase the stroke of the welding equipment on a single negative electrode welding wire 51, thereby reducing the welding efficiency and affecting the production efficiency of cylindrical secondary batteries.

[0063] Therefore, in this application, the internal protrusion height W12 of each negative electrode bonding wire 51 is set to a range of 0.15mm to 0.35mm. This prevents the fluctuation range of each corrugation of the negative electrode bonding wire 51 from being too small or too large, thus preventing excessive heat concentration at the negative electrode solder mark 5 during welding and reducing the stroke of the welding equipment on a single negative electrode bonding wire 51. This, in turn, ensures the performance of the cylindrical secondary battery and improves the production efficiency of the cylindrical secondary battery. In practical implementation, preferably, the internal protrusion height W12 of each negative electrode bonding wire 51 is set to 0.25mm.

[0064] In practical use, if the included angle B of each corrugation of the negative electrode bonding wire 51 is designed to be too small, the number of corrugations of the negative electrode bonding wire 51 will increase when the length L1 of the negative electrode solder mark 5 is limited. This will result in the negative electrode bonding wire 51 being more dense, which will cause the heat at the negative electrode bonding wire 51 to be more concentrated during the welding process, making it easy for issues such as soldering through and explosion to occur, thus affecting the performance of the cylindrical secondary battery.

[0065] If the included angle B of each corrugation of the negative electrode welding line 51 is designed to be too large, the number of corrugations of the negative electrode welding line 51 will be reduced when the length L1 of the negative electrode welding line 5 is limited. This will result in a reduction in the length of each negative electrode welding line 51, thereby reducing the current carrying capacity of the negative electrode current collector 3 and the connection strength between the negative electrode current collector 3 and the negative electrode tab of the core 1, which will in turn affect the performance of the cylindrical secondary battery.

[0066] Therefore, in this application, the included angle B of each corrugation of the negative electrode bonding wire 51 is set between 70° and 120° to prevent the included angle B of each corrugation of the negative electrode bonding wire 51 from being too small or too large. This prevents excessive heat concentration at the negative electrode bonding wire 51 during welding, while ensuring the current carrying capacity of the negative electrode current collector 3 and the connection strength between the negative electrode current collector 3 and the negative terminal tab of the core 1, thereby ensuring the performance of the cylindrical secondary battery. In practical implementation, preferably, the included angle B of each corrugation of the negative electrode bonding wire 51 is set to 95°.

[0067] In the preceding embodiments, the ratio of the length L0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21 (L0 / R0), the ratio of the width W0 of the positive electrode solder mark 4 to the radius R0 of the disk body 21 (W0 / R0), the range of the length L0 of the positive electrode solder mark 4, and the range of the width W0 of the positive electrode solder mark 4 were defined. Therefore, in this embodiment, the radius R0 of the disk body 21 is set to a range of 8.8 mm to 9.4 mm to ensure that the ratios L0 / R0 and W0 / R0 are within the aforementioned defined ranges. In actual implementation, preferably, the radius R0 of the disk body 21 is set to 9.1 mm.

[0068] In the preceding embodiments, the ratio of the length L1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3 (L1 / R1), the ratio of the width W1 of the negative electrode solder mark 5 to the radius R1 of the negative electrode current collector 3 (W1 / R1), the range of the length L1 of the negative electrode solder mark 5, and the range of the width W1 of the negative electrode solder mark 5 were defined. Therefore, in this embodiment, the radius R1 of the negative electrode current collector 3 is set to a range of 8.5mm to 10.5mm to ensure that the ratios L1 / R1 and W1 / R1 are within the aforementioned defined ranges. In actual implementation, preferably, the radius R1 of the negative electrode current collector 3 is set to 9.5mm.

[0069] The above-described contents can be implemented individually or in combination in various ways, and all such variations are within the protection scope of this utility model.

[0070] 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.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A cylindrical secondary battery, comprising a core (1), a positive current collector (2), and a negative current collector (3), wherein the positive current collector (2) comprises a disk body (21), the disk body (21) is connected to the positive terminal tab of the core (1) via a positive electrode solder joint (4), and the negative current collector (3) is connected to the negative terminal tab of the core (1) via a negative electrode solder joint (5), characterized in that: The ratio of the length L0 of the positive electrode solder mark (4) to the radius R0 of the disk body (21) is L0 / R0, which is 42.9% to 56%. The ratio of the width W0 of the positive electrode solder mark (4) to the radius R0 of the disk body (21) is W0 / R0, which is 26.4% to 35.2%. The ratio of the length L1 of the negative electrode solder mark (5) to the radius R1 of the negative electrode current collector (3) is L1 / R1, which is 37% to 57%. The ratio of the width W1 of the negative electrode solder mark (5) to the radius R1 of the negative electrode current collector (3) is W1 / R1, which is 17% to 36%.

2. A cylindrical secondary battery as described in claim 1, characterized in that: The length L0 of the positive electrode solder mark (4) ranges from 3.9 mm to 5.1 mm, and the width W0 of the positive electrode solder mark (4) ranges from 2.4 mm to 3.2 mm.

3. A cylindrical secondary battery as described in claim 1, characterized in that: The length L1 of the negative electrode solder mark (5) ranges from 3.5 mm to 5.5 mm, and the width W1 of the negative electrode solder mark (5) ranges from 1.6 mm to 3.4 mm.

4. A cylindrical secondary battery as described in claim 2, characterized in that: The positive electrode solder mark (4) includes multiple positive electrode solder lines (41) arranged circumferentially around the central axis of the disk body (21), and the width W01 of each positive electrode solder line (41) ranges from 0.2mm to 0.4mm.

5. A cylindrical secondary battery as described in claim 4, characterized in that: The positive electrode bonding wire (41) is corrugated, and the included angle A of each corrugation of the positive electrode bonding wire (41) ranges from 10° to 30°.

6. A cylindrical secondary battery as described in claim 3, characterized in that: The negative electrode solder mark (5) is a plurality of such marks arranged circumferentially around the central axis of the negative electrode current collector (3). Each negative electrode solder mark (5) includes a plurality of negative electrode welding lines (51) arranged in parallel and spaced apart. The distance W10 between two adjacent negative electrode welding lines (51) ranges from 0.6 mm to 1.1 mm.

7. A cylindrical secondary battery as described in claim 6, characterized in that: The width W11 of each of the negative electrode bonding wires (51) ranges from 0.1 mm to 0.3 mm.

8. A cylindrical secondary battery as described in claim 6, characterized in that: The negative electrode bonding wire (51) is corrugated, and the internal protrusion height W12 of each negative electrode bonding wire (51) ranges from 0.15mm to 0.35mm.

9. A cylindrical secondary battery as described in claim 8, characterized in that: The included angle B of each corrugation of the negative electrode bonding wire (51) ranges from 70° to 120°.

10. A cylindrical secondary battery as described in claim 1, characterized in that: The radius R0 of the disk body (21) ranges from 8.8 mm to 9.4 mm, and the radius R1 of the negative electrode current collector (3) ranges from 8.5 mm to 10.5 mm.

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