A cylindrical lithium-ion battery

Abstract

The utility model relates to a kind of cylindrical lithium ion batteries.It involves new energy battery technical field.The present application specifically includes disc body weld mark is the multiple that is arranged in the circumferential direction of the middle axis of the disc body and the roll core, the sum of the area of multiple disc body weld mark is S100, the ratio S100 / S0 of S0 is 13.3%~17.7%, the area S20 of tail body weld mark, the ratio S20 / S1 of the area S1 of lower end plate is 3.2%~6.4%.The utility model sets the ratio S100 / S0 between the sum S100 of the area of multiple disc body weld mark and the area S0 of roll core between 13.3%~17.7%, the ratio S20 / S1 between the area S20 of tail body weld mark and the area S1 of lower end plate is set between 3.2%~6.4%, both can guarantee the overcurrent capacity of positive current collector disc, can reduce welding time, improve welding efficiency, reduce welding failure rate simultaneously, to improve the production efficiency of cylindrical lithium ion battery, and guarantee the performance of cylindrical lithium ion battery.

Description

Technical Field

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

[0002] Cylindrical lithium-ion 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 lithium-ion battery consists of a core, a cap, and a positive current collector. The positive current collector comprises a disc body and a tail body. The disc body is welded to the positive electrode tab of the core, and the tail body is welded to the lower end plate of the cap. This allows for connection and current flow through the positive current collector, while the cap leads out the positive electrode of the core.

[0003] The positive current collector typically has solder marks on its body and tail. The solder marks on the body are used for welding to the positive electrode tab of the core, and the solder marks on the tail are used for welding to the lower end plate of the cap. In the prior art, the design of the positive current collector of cylindrical lithium-ion batteries is not entirely reasonable, especially the area design of the solder marks on the body and tail of the positive current collector.

[0004] Some cylindrical lithium-ion batteries have solder areas on the disc and tail section that are designed too small, which weakens the current-carrying capacity of the solder and causes greater heat generation in the solder area during current flow, resulting in higher temperatures at the solder joint and increased internal resistance of the battery, thus affecting battery performance. On the other hand, some cylindrical lithium-ion batteries have solder areas on the disc and tail section that are designed too large, which increases soldering time, reduces soldering efficiency, increases the risk of soldering defects, and increases the defect rate. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a cylindrical lithium-ion battery that can ensure the current carrying capacity of the positive electrode current collector, reduce welding time, improve welding efficiency, and reduce welding defect rate, thereby improving the production efficiency of cylindrical lithium-ion batteries and ensuring their performance.

[0006] This utility model proposes a cylindrical lithium-ion battery, including a core, a lower end plate, and a positive electrode current collector. The positive electrode current collector includes a disk body and a tail body. The disk body is connected to the positive terminal tab of the core via a disk body solder joint. The tail body is connected to the lower end plate via a tail body solder joint. The radius of the core is R0, and the area of ​​the core calculated based on the radius R0 is S0. The length of the disk body solder joint is L10, and the width is W10. The area of ​​the disk body solder joint calculated based on the length L10 and the width W10 is S10. The disk body solder joint is... A plurality of plates are arranged circumferentially around the central axis of the disc and the core. The sum of the areas of the solder marks on the plurality of discs is S100, and the ratio of S100 to S0, S100 / S0, ​​is 13.3% to 17.7%. The radius of the lower end plate is R1, and the area of ​​the lower end plate calculated based on the radius R1 is S1. The length of the tail body solder mark is L20, and the width is W20. The area of ​​the tail body solder mark calculated based on the length L20 and the width W20 is S20, and the ratio of S20 to S1, S20 / S1, is 3.2% to 6.4%.

[0007] Furthermore, the ratio of the area S10 of the solder mark on the disc to the area S0 of the core, S10 / S0, ​​is 3.3% to 4.4%, the area S10 of the solder mark on the disc ranges from 11 mm2 to 13 mm2, and the area S20 of the solder mark on the tail body ranges from 5 mm2 to 7 mm2.

[0008] Furthermore, the ratio of the length L10 of the solder mark on the disc to the radius R0 of the core, L10 / R0, is 38.3% to 50.1%, and the ratio of the width W10 of the solder mark on the disc to the radius R0 of the core, W10 / R0, is 23.6% to 31.4%.

[0009] Furthermore, the ratio of the width W20 of the tail body solder mark to the radius R1 of the lower end plate, W20 / R1, is 15% to 32%, and the ratio of the length L20 of the tail body solder mark to the width W30 of the tail body, L20 / W30, is 56% to 76%.

[0010] Furthermore, the solder mark on the disk body is a wavy solder line extending from the disk body, and the width W101 of the solder line ranges from 0.2mm to 0.4mm.

[0011] Furthermore, the included angle A of each corrugation of the welding wire on the disk ranges from 10° to 30°.

[0012] Furthermore, the tail body solder mark is a tail body solder line extending in a corrugated shape, and the width W201 of the tail body solder line ranges from 0.2mm to 0.4mm.

[0013] Furthermore, the included angle B of each corrugation of the tail body welding line ranges from 25° to 65°.

[0014] Furthermore, the disc body is provided with a central hole and a plurality of peripheral holes located outside the central hole. A plurality of the disc body solder marks are located outside the central hole and are spaced apart from the plurality of peripheral holes. The ratio of the radius R2 of the disc body to the radius R0 of the core, R2 / R0, is 86.4% to 92.3%, and the radius R0 of the core ranges from 9.18 mm to 11.18 mm.

[0015] Furthermore, the lower end plate is provided with a central boss and air holes arranged around the outer periphery of the central boss. The tail body solder mark is located between the central boss and the air holes. The radius R1 of the lower end plate ranges from 5.29 mm to 7.29 mm, and the width W30 of the tail body ranges from 5 mm to 7 mm.

[0016] The cylindrical lithium-ion battery proposed in this utility model has the following beneficial effects:

[0017] (1) The ratio S100 / S0 of the sum of the areas of multiple disc solderings S100 to the area S0 of the core is set between 13.3% and 17.7% in this battery, thereby preventing the total area of ​​the disc solderings from being too small or too large. This ensures the current carrying capacity of the disc solderings, reduces the welding time between the disc and the core positive electrode tab, reduces the risk of poor welding, and thus improves the production efficiency of cylindrical lithium-ion batteries and ensures the performance of cylindrical lithium-ion batteries.

[0018] (2) The ratio of the area S20 of the tail body soldering to the area S1 of the lower end plate is set between 3.2% and 6.4% in this battery, thereby preventing the area of ​​the tail body soldering from being too small or too large. This ensures the current carrying capacity of the tail body soldering, reduces the welding time between the tail body and the lower end plate of the cap, reduces the risk of poor welding, and thus improves the production efficiency of cylindrical lithium-ion batteries and ensures the performance of cylindrical lithium-ion batteries.

[0019] (3) The ratio of the area S10 of a single disc to the area S0 of the core is set between 3.3% and 4.4% in this battery. This ensures that the current carrying capacity of the disc is guaranteed, while reducing the welding time between the disc and the core positive electrode tab, thus reducing the risk of poor welding and improving the production efficiency of cylindrical lithium-ion batteries while ensuring the performance of cylindrical lithium-ion batteries.

[0020] (4) The ratio of the length L10 of the disc soldering to the radius R0 of the core is set to 38.3% to 50.1%, and the ratio of the width W10 of the disc soldering to the radius R0 of the core is set to 23.6% to 31.4%, thereby preventing the length L10 and width W10 of the disc soldering from being too small or too large, thus ensuring the performance of the cylindrical lithium-ion battery.

[0021] (5) The ratio of the width W20 of the tail soldering to the radius R1 of the lower end plate is set to 15% to 32%, and the ratio of the length L20 of the tail soldering to the width W30 of the tail is set to 56% to 76%, thereby preventing the length L20 and width W20 of the tail soldering from being too small or too large, thus ensuring the performance of the cylindrical lithium-ion battery. Attached Figure Description

[0022] 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.

[0023] Figure 1 This is a planar schematic diagram of a cylindrical lithium-ion battery according to an embodiment of the present invention, showing the connection between the disc body and the positive electrode tab of the winding core through soldering on the disc body.

[0024] Figure 2 This is a plan view showing the connection between the tail and the lower end plate of the cap of a cylindrical lithium-ion battery according to an embodiment of the present invention, via a tail body solder joint.

[0025] Figure 3 for Figure 1 Enlarged view of point C in the middle;

[0026] Figure 4 for Figure 2 Enlarged diagram of point D in the middle.

[0027] In the diagram: 1. Core; 2. Lower end plate; 21. Middle boss; 22. Air hole; 3. Disc body; 31. Center hole; 32. Outer hole; 4. Tail body; 5. Disc body solder mark; 51. Disc body solder line; 6. Tail body solder mark; 61. Tail body solder line. Detailed Implementation

[0028] 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.

[0029] A cylindrical lithium-ion battery according to an embodiment of the present invention includes a core 1, a lower end plate 2, and a positive electrode current collector. The positive electrode current collector includes a plate body 3 and a tail body 4. When the tail body 4 is unfolded, one end is connected to the plate body 3 and the other end extends away from the plate body 3. After the tail body 4 is bent, the end extending away from the plate body 3 is located above the plate body 3 and is parallel to the plate body 3.

[0030] The disc 3 is welded to the positive electrode tab of the core 1 through the disc welding mark 5, thereby realizing the connection between the positive current collector and the positive electrode tab of the core 1; the tail 4 is welded to the lower end plate 2 of the cap through the tail welding mark 6, thereby realizing the connection between the positive current collector and the cap. The positive current collector is used for connection and current flow, so that the cap leads out the positive electrode of the core 1.

[0031] In practical use, if the area of ​​the plate solder mark 5 and the tail solder mark 6 is designed to be too small, the current carrying capacity of the plate solder mark 5 and the tail solder mark 6 will be weakened. This will result in greater heat generation in the area where the plate solder mark 5 and the tail solder mark 6 are located during current carrying, which will lead to an increase in the temperature at the welding point and an increase in the internal resistance of the battery, affecting the performance of the cylindrical lithium-ion battery.

[0032] If the area of ​​the plate solder mark 5 and the tail solder mark 6 is designed to be too large, it will increase the welding time between the plate 3 and the positive electrode tab of the core 1 and the tail 4 and the lower end plate 2 of the cap, reduce the welding efficiency, thereby reducing the production efficiency of cylindrical lithium-ion batteries, and increase the risk of welding defects, thus increasing the welding defect rate and affecting the performance of cylindrical lithium-ion batteries.

[0033] The radius of the core 1 is R0, and the area of ​​the core 1 calculated based on the radius R0 is S0. The length of the disk solder mark 5 is L10, and the width is W10. The area of ​​the disk solder mark 5 calculated based on the length L10 and the width W10 is S10. In this application, there are multiple disk solder marks 5 distributed circumferentially along the central axis on the disk 3. The area of ​​each disk solder mark 5 is S10, and the sum of the areas of the multiple disk solder marks 5 is S100. It can be foreseen that: S10 = L10 * W10, S100 = S10 * number of disk solder marks 5.

[0034] The ratio S100 / S0 of the sum of the areas S100 of the multiple disk solder marks 5 to the area S0 of the core 1 is set between 13.3% and 17.7%, thereby preventing the total area of ​​the disk solder marks 5 from being too small or too large. This ensures the current carrying capacity of the disk solder marks 5, reduces the welding time between the disk 3 and the positive electrode tab of the core 1, reduces the risk of welding defects, and thus improves the production efficiency of cylindrical lithium-ion batteries while ensuring the performance of cylindrical lithium-ion batteries.

[0035] The radius of the lower end plate 2 is R1, and the area of ​​the lower end plate 2 calculated based on the radius R1 is S1. The length of the tail body weld mark 6 is L20 and the width is W20, and the area of ​​the tail body weld mark 6 calculated based on the length L20 and the width W20 is S20.

[0036] In this application, the ratio S20 / S1 of the area S20 of the tail body solder mark 6 to the area S1 of the lower end plate 2 is set between 3.2% and 6.4%, thereby preventing the area of ​​the tail body solder mark 6 from being too small or too large. This ensures the current carrying capacity of the tail body solder mark 6, reduces the welding time between the tail body 4 and the lower end plate 2 of the cap, reduces the risk of welding defects, and thus improves the production efficiency of cylindrical lithium-ion batteries while ensuring the performance of cylindrical lithium-ion batteries.

[0037] In actual implementation, preferably, the ratio of the sum of the areas S100 of the multiple disc solder marks 5 to the area S0 of the core 1, S100 / S0, ​​is set to 15.5%; and the ratio of the area S20 of the tail solder mark 6 to the area S1 of the lower end plate 2, S20 / S1, is set to 4.8%.

[0038] Furthermore, in this embodiment, the ratio S10 / S0 of the area S10 of a single disk solder mark 5 to the area S0 of the core 1 is set between 3.3% and 4.4%, thereby preventing the area of ​​the disk solder mark 5 from being too small or too large. This ensures the current carrying capacity of the disk solder mark 5, reduces the welding time between the disk 3 and the positive electrode tab of the core 1, reduces the risk of welding defects, and thus improves the production efficiency of cylindrical lithium-ion batteries while ensuring the performance of cylindrical lithium-ion batteries.

[0039] Specifically, in this application, the area S10 of a single disc solder mark 5 is set between 11 mm² and 13 mm². Therefore, after determining the value of S10, the area S0 of the core 1 can be obtained based on the value of S10 and the ratio S10 / S0. Then, based on the value of S0 and the ratio S100 / S0, ​​the sum of the areas S100 of the multiple disc solder marks 5 can be obtained. Based on the values ​​of S100 and S10, the number of disc solder marks 5 used for connecting the disc 3 to the positive electrode tab of the core 1 can be determined.

[0040] In practical implementation, preferably, the ratio S10 / S0 of the area S10 of a single disc solder mark 5 to the area S0 of the core 1 is set to 3.9%, and the area S10 of a single disc solder mark 5 is set to 12 mm2. That is, preferably, the area S0 of the core 1 is 308 mm2, and the sum of the areas S100 of multiple disc solder marks 5 is 48 mm2. Therefore, it can be determined that the disc solder marks 5 are four distributed circumferentially along the central axis on the disc 3.

[0041] Specifically, in this application, the area S20 of the tail weld mark 6 is set between 5 mm² and 7 mm². Therefore, after determining the value of S20, the area S1 of the lower end plate 2 can be obtained based on the value of S20 and the ratio S20 / S1. In practical implementation, preferably, the area S20 of the tail weld mark 6 is set to 6 mm², that is, preferably, the area S1 of the lower end plate 2 is 125 mm².

[0042] In the above embodiments, although the area S10 of a single disk solder mark 5 can be determined, the specific length L10 and width W10 of the disk solder mark 5 are not determined. In actual use, if the length L10 of the disk solder mark 5 is designed to be too small and the width W10 is designed to be too large, the heat at the disk solder mark 5 will be concentrated during the welding process, which will easily lead to solder burn-through, explosion points, etc., affecting the performance of the cylindrical lithium-ion battery.

[0043] If the length L10 of the solder mark 5 on the disk is designed to be too large and the width W10 is designed to be too small, the solder mark 5 on the disk may exceed the weldable area of ​​the disk 3, thereby affecting the welding effect between the disk 3 and the positive electrode tab of the core 1, and thus affecting the performance of the cylindrical lithium-ion battery.

[0044] Therefore, in this embodiment, the ratio of the length L10 of the disc solder mark 5 to the radius R0 of the core 1, L10 / R0, is set to 38.3% to 50.1%, and the ratio of the width W10 of the disc solder mark 5 to the radius R0 of the core 1, W10 / R0, is set to 23.6% to 31.4%. This ensures that the ratio of the area S10 of a single disc solder mark 5 to the area S0 of the core 1, S10 / S0, ​​and the ratio of the sum of the areas S100 of multiple disc solder marks 5 to the area S0 of the core 1, S100 / S0, ​​are within the above-defined range. At the same time, it prevents the length L10 and width W10 of the disc solder mark 5 from being too small or too large, thereby ensuring the performance of the cylindrical lithium-ion battery.

[0045] In practical implementation, preferably, the ratio of the length L10 of the disc body solder mark 5 to the radius R0 of the core 1, L10 / R0, is set to 44.2%, and the ratio of the width W10 of the disc body solder mark 5 to the radius R0 of the core 1, W10 / R0, is set to 27.5%.

[0046] In the above embodiments, although the area S20 of the tail solder mark 6 can be determined, the specific length L20 and width W20 of the tail solder mark 6 are not determined. In actual use, if the length L20 of the tail solder mark 6 is designed to be too small and the width W20 is designed to be too large, the heat at the tail solder mark 6 will be concentrated during the welding process, which will easily lead to solder burn-through, explosion points, etc., affecting the performance of the cylindrical lithium-ion battery.

[0047] If the length L20 of the tail body solder mark 6 is designed to be too large and the width W20 is designed to be too small, the tail body solder mark 6 may exceed the weldable area of ​​the tail body 4, thereby affecting the welding effect between the tail body 4 and the lower end plate 2 of the cap, and thus affecting the performance of the cylindrical lithium-ion battery.

[0048] Therefore, in this embodiment, the ratio of the width W20 of the tail body solder mark 6 to the radius R1 of the lower end plate 2, W20 / R1, is set to 15% to 32%, and the ratio of the length L20 of the tail body solder mark 6 to the width W30 of the tail body 4, L20 / W30, is set to 56% to 76%. This ensures that the ratio of the area S20 of the tail body solder mark 6 to the area S1 of the lower end plate 2, S20 / S1, is within the above-defined range, while preventing the length L20 and width W20 of the tail body solder mark 6 from being too small or too large, thereby ensuring the performance of the cylindrical lithium-ion battery.

[0049] In actual implementation, preferably, the ratio of the width W20 of the tail body weld mark 6 to the radius R1 of the lower end plate 2, W20 / R1, is set to 24%, and the ratio of the length L20 of the tail body weld mark 6 to the width W30 of the tail body 4, L20 / W30, is set to 67%.

[0050] In this embodiment, the disk body solder mark 5 is a disk body solder line 51 that extends in a corrugated shape. This increases the welding area between the disk body 3 and the positive electrode tab of the core 1 when the length L0 of the disk body solder mark 5 is limited. This enhances both the current carrying capacity of the positive electrode current collector and the connection strength between the positive electrode current collector and the positive electrode tab of the core 1, thereby ensuring the performance of the cylindrical lithium-ion battery.

[0051] In practical use, if the width of the welding line 51 is designed to be too small, the welding area between the disc 3 and the positive electrode tab of the core 1 will be reduced, thereby reducing the current carrying capacity of the positive electrode current collector and affecting the performance of the cylindrical lithium-ion battery. On the other hand, if the width of the welding line 51 is designed to be too large, the heat at the welding line 51 will be too high during the welding process, which may easily lead to burn-through, explosion and other problems, which will also affect the performance of the cylindrical lithium-ion battery.

[0052] Therefore, in this application, the width W101 of the bonding wire 51 is set between 0.2mm and 0.4mm to prevent the width W101 from being too small or too large. This ensures both the current carrying capacity of the positive electrode current collector and prevents excessive heat at the bonding wire 51, which could lead to solder burn-through, explosion, or other issues, thereby guaranteeing the performance of the cylindrical lithium-ion battery. In practical implementation, it is preferable to set the width W101 of the bonding wire 51 to 0.3mm.

[0053] In practical use, if the included angle A of each corrugation of the disk bonding line 51 is designed to be too small, the number of corrugations of the disk bonding line 51 will increase when the length L10 of the disk bonding mark 5 is limited. This will result in the disk bonding line 51 being more dense, which will cause the heat at the disk bonding line 51 to be more concentrated during the welding process, making it easy for issues such as burn-through and explosion to occur, thus affecting the performance of the cylindrical lithium-ion battery.

[0054] If the included angle A of each corrugation of the disk bonding line 51 is designed to be too large, the number of corrugations of the disk bonding line 51 will be reduced when the length L10 of the disk bonding mark 5 is limited. This will result in a reduction in the extension length of the disk bonding line 51, thereby reducing the current carrying capacity of the positive current collector and the connection strength between the positive current collector and the positive electrode tab of the core 1, which in turn will affect the performance of the cylindrical lithium-ion battery.

[0055] Therefore, in this application, the included angle A of each corrugation of the disk bonding wire 51 is set between 10° and 30° to prevent the included angle A of each corrugation of the disk bonding wire 51 from being too small or too large. This prevents excessive heat concentration at the disk bonding wire 51 during welding, while ensuring the current carrying capacity of the positive electrode current collector and the connection strength between the positive electrode current collector and the positive electrode tab of the core 1, thereby ensuring the performance of the cylindrical lithium-ion battery. In practical implementation, preferably, the included angle A of each corrugation of the disk bonding wire 51 is set to 18°.

[0056] In this embodiment, the tail body solder mark 6 is a corrugated tail body solder line 61, thereby increasing the welding area between the tail body 4 and the lower end plate 2 of the cap when the length L20 of the tail body solder mark 6 is limited. This enhances both the current carrying capacity of the positive electrode current collector and the connection strength between the positive electrode current collector and the lower end plate 2 of the cap, thus ensuring the performance of the cylindrical lithium-ion battery.

[0057] In practical use, if the width of the tail welding line 61 is designed to be too small, the welding area between the tail 4 and the lower end plate 2 of the cap will be reduced, thereby reducing the current carrying capacity of the positive current collector and affecting the performance of the cylindrical lithium-ion battery. On the other hand, if the width of the tail welding line 61 is designed to be too large, the heat at the tail welding line 61 will be too high during the welding process, which may easily lead to burn-through, explosion and other problems, which will also affect the performance of the cylindrical lithium-ion battery.

[0058] Therefore, in this application, the width W201 of the tail welding line 61 is set between 0.2mm and 0.4mm to prevent the width W201 from being too small or too large. This ensures both the current carrying capacity of the positive electrode current collector and prevents excessive heat at the tail welding line 61, which could lead to solder burn-through, explosion, or other issues, thereby guaranteeing the performance of the cylindrical lithium-ion battery. In practical implementation, it is preferable to set the width W201 of the tail welding line 61 to 0.3mm.

[0059] In practical use, if the included angle B of each corrugation of the tail welding line 61 is designed to be too small, the number of corrugations of the tail welding line 61 will increase when the length L20 of the tail welding line 6 is limited. This will result in the tail welding line 61 being more dense, which will cause the heat at the tail welding line 61 to be more concentrated during the welding process, making it easy for issues such as burn-through and explosion to occur, thus affecting the performance of the cylindrical lithium-ion battery.

[0060] If the included angle B of each corrugation of the tail welding line 61 is designed to be too large, the number of corrugations of the tail welding line 61 will be reduced when the length L20 of the tail welding line 6 is limited. This will result in a reduction in the length of the tail welding line 61, thereby reducing the current carrying capacity of the positive current collector and the connection strength between the positive current collector and the lower end plate 2 of the cap, which in turn will affect the performance of the cylindrical lithium-ion battery.

[0061] Therefore, in this application, the included angle B of each corrugation of the tail welding line 61 is set between 25° and 65° to prevent the included angle B of each corrugation of the tail welding line 61 from being too small or too large. This prevents excessive heat concentration at the tail welding line 61 during welding, ensures the current carrying capacity of the positive electrode current collector, and the connection strength between the positive electrode current collector and the lower end plate 2 of the cap, thereby ensuring the performance of the cylindrical lithium-ion battery. In practical implementation, preferably, the included angle B of each corrugation of the tail welding line 61 is set to 41°.

[0062] It can be foreseen that: since the disk body solder mark 5 is a wavy extended disk body solder line 51, the area S10 of the disk body solder mark 5 calculated using the length L10 and width W10 of the disk body solder mark 5 is a rectangular area with a length of L10 and a width of W10; the area S20 of the tail body solder mark 6 calculated using the length L20 and width W20 of the tail body solder mark 6 is a rectangular area with a length of L20 and a width of W20.

[0063] In this embodiment, the disk body 3 is provided with a central hole 31 and multiple peripheral holes 32. Both the central hole 31 and the multiple peripheral holes 32 penetrate the disk body 3, and the multiple peripheral holes 32 are distributed outside the central hole 31. Both the central hole 31 and the peripheral holes 32 are used to inject electrolyte into the battery casing. After the electrolyte is injected through the injection port on the cap, the electrolyte flows through the central hole 31 into the battery casing.

[0064] If the injection speed is greater than the speed at which the electrolyte flows through the central hole 31, the excess electrolyte will diffuse outwards from the central hole 31. At this time, the electrolyte that has diffused outwards from the central hole 31 can enter the battery casing through multiple peripheral holes 32, thereby assisting the injection of electrolyte into the central hole 31 through multiple peripheral holes 32, improving the electrolyte injection efficiency of the battery, and thus improving the battery production efficiency.

[0065] Multiple solder marks 5 are also provided on the outside of the central hole 31 and spaced apart from multiple peripheral holes 32, thereby preventing the solder marks 5 from overlapping with the central hole 31 and peripheral holes 32, which would affect the electrolyte filling efficiency of the battery. Since the cylindrical lithium-ion battery of this application is connected and passes current through the positive electrode current collector, the cap leads out the positive electrode of the core 1, while the negative electrode of the core 1 is led out through the battery casing. Therefore, the positive electrode current collector is positively charged, and the battery casing is negatively charged.

[0066] In practical use, if the radius of the disc 3 is set too large, it will increase the risk of the disc 3 contacting the inner wall of the battery casing, thereby increasing the risk of short circuit in the cylindrical lithium-ion battery and affecting its use. If the radius of the disc 3 is set too small, it will reduce the effective welding area of ​​the disc 3 that can be used to weld with the positive electrode tab of the core 1, thereby reducing the current carrying capacity of the disc solder mark 5 and thus affecting the performance of the cylindrical lithium-ion battery.

[0067] Since the diameter of the core 1 is matched with the inner diameter of the battery casing, in this application, the ratio R2 / R0 of the radius R2 of the disk 3 to the radius R0 of the core 1 is set between 86.4% and 92.3%. This prevents the radius R2 of the disk 3 from being too small or too large, thereby enhancing the current-carrying capacity of the positive electrode current collector, ensuring the performance of the cylindrical lithium-ion battery, and reducing the risk of short circuits in the cylindrical lithium-ion battery, ensuring its normal use. In practical implementation, preferably, the ratio R2 / R0 of the radius R2 of the disk 3 to the radius R0 of the core 1 is set to 91%.

[0068] Specifically, in this application, the radius R0 of the core 1 is set between 9.18 mm and 11.18 mm. After determining the value of the radius R0 of the core 1, the values ​​of L10, W10, and R2 are obtained based on the ratios L10 / R0, W10 / R0, and R2 / R0. In practical implementation, preferably, the radius R0 of the core 1 is set to 9.9 mm. That is, preferably, the length L10 of the disc body solder mark 5 is 4 mm, the width W10 of the disc body solder mark 5 is 3 mm, and the radius R2 of the disc body 3 is 9 mm.

[0069] In this embodiment, the lower end plate 2 is provided with a central boss 21 and an air hole 22. The central boss 21 is used to lead out the positive electrode of the core 1, and the air hole 22 is arranged around the outer periphery of the central boss 21 to release gas inside the battery casing. When the tail body 4 is welded to the lower end plate 2 by the tail body solder mark 6, the tail body solder mark 6 is located in the area between the central boss 21 and the air hole 22, and the end of the tail body 4 abuts against the central boss 21, thereby making the tail body 4 and the central boss 21 conductive, and thus realizing the conductivity between the positive electrode current collector and the cap.

[0070] In practical use, if the width of the tail body 4 is designed to be too small, it will compress the length of the tail body solder mark 6, thereby affecting the current carrying capacity of the positive current collector; while if the width of the tail body 4 is designed to be too large, it will cause the tail body 4 to cover the air hole 22, affecting the current carrying capacity of the air hole 22.

[0071] Therefore, in this application, the width W30 of the tail body 4 is set between 5mm and 7mm to prevent the width W30 of the tail body 4 from being too small or too large, thereby ensuring both the current-carrying capacity of the positive electrode current collector and the current-carrying capacity of the vent 22, and thus ensuring the performance of the cylindrical secondary battery. In actual implementation, preferably, the width W30 of the tail body 4 is set to 6mm.

[0072] In this application, the radius R1 of the lower end plate 2 is set between 5.29 mm and 7.29 mm. Therefore, after determining the values ​​of the radius R1 of the lower end plate 2 and the width W30 of the tail body 4, the values ​​of the width W20 and length L20 of the tail body solder mark 6 can be determined according to the ratios W20 / R1 and L20 / W30. In practical implementation, it is preferred that R1 is set to 6.3 mm, that is, preferably, the width W20 of the tail body solder mark 6 is 1.5 mm and the length L20 of the tail body solder mark 6 is 4 mm.

[0073] 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.

Claims

1. A cylindrical lithium-ion battery, comprising a core (1), a lower end plate (2), and a positive electrode current collector, wherein the positive electrode current collector comprises a plate body (3) and a tail body (4), the plate body (3) is connected to the positive terminal tab of the core (1) via a plate body solder joint (5), and the tail body (4) is connected to the lower end plate (2) via a tail body solder joint (6), characterized in that: The radius of the core (1) is R0, and the area of ​​the core (1) calculated based on the radius R0 is S0. The length of the disc solder mark (5) is L10, and the width is W10. The area of ​​the disc solder mark (5) calculated based on the length L10 and the width W10 is S10. The disc solder mark (5) consists of multiple pieces arranged circumferentially around the central axis of the disc (3) and the core (1). The sum of the areas of the multiple disc solder marks (5) is S100. The ratio of S100 to S0, S100 / S0, ​​is 13.3% to 17.7%; the radius of the lower end plate (2) is R1, and the area of ​​the lower end plate (2) calculated with radius R1 is S1; the length of the tail body solder mark (6) is L20 and the width is W20, and the area of ​​the tail body solder mark (6) calculated with length L20 and width W20 is S20; the ratio of S20 to S1, S20 / S1, is 3.2% to 6.4%.

2. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The ratio of the area S10 of the disc body solder mark (5) to the area S0 of the core (1) is 3.3% to 4.4%, the area S10 of the disc body solder mark (5) is 11 mm2 to 13 mm2, and the area S20 of the tail body solder mark (6) is 5 mm2 to 7 mm2.

3. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The ratio of the length L10 of the solder mark (5) to the radius R0 of the core (1) is 38.3% to 50.1%, and the ratio of the width W10 of the solder mark (5) to the radius R0 of the core (1) is 23.6% to 31.4%.

4. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The ratio of the width W20 of the tail body weld mark (6) to the radius R1 of the lower end plate (2) is 15% to 32%, and the ratio of the length L20 of the tail body weld mark (6) to the width W30 of the tail body (4) is 56% to 76%.

5. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The disk body solder mark (5) is a disk body solder line (51) extending in a corrugated shape, and the width W101 of the disk body solder line (51) ranges from 0.2mm to 0.4mm.

6. A cylindrical lithium-ion battery as described in claim 5, characterized in that: The included angle A of each corrugation of the disk bonding wire (51) ranges from 10° to 30°.

7. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The tail body weld mark (6) is a tail body weld line (61) extending in a corrugated shape, and the width W201 of the tail body weld line (61) ranges from 0.2mm to 0.4mm.

8. A cylindrical lithium-ion battery as described in claim 7, characterized in that: The included angle B of each corrugation of the tail weld line (61) ranges from 25° to 65°.

9. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The disc body (3) is provided with a central hole (31) and a plurality of peripheral holes (32) located outside the central hole (31). A plurality of disc body solder marks (5) are located outside the central hole (31) and are spaced apart from the plurality of peripheral holes (32). The ratio of the radius R2 of the disc body (3) to the radius R0 of the core (1) is 86.4% to 92.3%. The radius R0 of the core (1) ranges from 9.18 mm to 11.18 mm.

10. A cylindrical lithium-ion battery as described in claim 4, characterized in that: The lower end plate (2) is provided with a central boss (21) and air holes (22) arranged around the outer periphery of the central boss (21). The tail body solder mark (6) is located between the central boss (21) and the air holes (22). The radius R1 of the lower end plate (2) is in the range of 5.29mm to 7.29mm, and the width W30 of the tail body (4) is in the range of 5mm to 7mm.

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