Cylindrical battery negative electrode collector plate welding structure and cylindrical secondary battery

Abstract

The utility model relates to a cylindrical battery cathode collector plate welding structure and a cylindrical secondary battery. Relates to the technical field of new energy batteries. The battery comprises a cathode collector plate and a welding mark arranged on the cathode collector plate, the cathode collector plate is used for connecting the cathode of the roll core with the bottom of a battery shell, and the welding mark is used for connecting the cathode collector plate with the cathode of the roll core; and the ratio L0 / R0 of the length L0 of the welding mark to the radius R0 of the negative collector plate is 37%-57%. According to the cylindrical secondary battery, the ratio L0 / R0 of the length L0 of the welding mark to the radius R0 of the negative collector plate is set between 37% and 57%, and the length L0 of the welding mark is prevented from being too large or too small, so that the overcurrent capacity of the welding mark can be ensured, the welding reject ratio can be reduced, the welding reliability is enhanced, and the performance of the cylindrical secondary battery is further ensured.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a welding structure for a cylindrical battery negative electrode current collector and 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. The negative electrode current collector, as a crucial component of cylindrical secondary batteries, is located inside the battery and is welded to the bottom of the casing, serving both connection and current-carrying functions. Therefore, optimizing the negative electrode current collector is particularly important in the design of cylindrical secondary batteries.

[0003] Cylindrical secondary batteries typically have solder marks on their negative electrode current collectors for welding the current collector to the negative electrode of the winding core. In existing technology, the design of the negative electrode current collector in cylindrical secondary batteries is not entirely reasonable, especially the length of the solder marks on the current collector.

[0004] Some negative electrode current collectors have solder lines that are too short, which weakens the current-carrying capacity of the solder lines. This results in greater heat generation in the area where the solder lines are located during current flow, leading to an increase in the temperature at the weld joint and an increase in the internal resistance of the battery, thus affecting the battery performance. On the other hand, some negative electrode current collectors have solder lines that are too long, which increases the risk of poor welding and reduces the reliability of the welding, also affecting the battery performance. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a cylindrical battery negative electrode current collector welding structure and a cylindrical secondary battery, which can ensure the current carrying capacity of the solder, reduce the welding defect rate, enhance the welding reliability, and thus guarantee the performance of the cylindrical secondary battery.

[0006] This utility model proposes a welding structure for a negative electrode current collector of a cylindrical battery, including a negative electrode current collector and a solder mark on the negative electrode current collector. The negative electrode current collector is used to connect the negative electrode of the winding core to the bottom of the battery casing, and the solder mark is used to connect the negative electrode current collector to the negative electrode of the winding core. The ratio of the length L0 of the solder mark to the radius R0 of the negative electrode current collector, L0 / R0, is 37% to 57%.

[0007] Furthermore, the negative electrode current collector includes a disk surface and a boss located at the center of the disk surface. The boss is used for welding to the battery casing. The solder marks extend radially on the disk surface and are distributed around the outer periphery of the boss. The radius R0 of the negative electrode current collector is the radius of the disk surface, and the ratio R1 / R0 of the radius R1 of the boss to the radius R0 of the disk surface is 24% to 40%.

[0008] Furthermore, the ratio L1 of the minimum distance L1 between the solder mark and the boss to the radius R0 of the disk surface, L1 / R0, is 5% to 16%.

[0009] Furthermore, the ratio of the minimum distance L2 between the solder mark and the edge of the disk surface to the radius R0 of the disk surface, L2 / R0, is 5% to 16%.

[0010] Furthermore, the minimum distance L1 between the solder mark and the boss ranges from 0.5mm to 1.5mm, and the minimum distance L2 between the solder mark and the edge of the disk surface ranges from 0.5mm to 1.5mm.

[0011] Furthermore, the solder marks are four that are symmetrically distributed in a cross shape on the outer periphery of the boss.

[0012] Furthermore, each of the solder marks includes three solder lines extending radially along the disk surface. The solder lines are corrugated, and the included angle B of each corrugation of the solder line is 70° to 120°.

[0013] Furthermore, the ratio of the width W0 of the solder mark to the radius R0 of the negative electrode current collector, W0 / R0, is 17% to 36%.

[0014] Furthermore, the length L0 of the solder mark ranges from 3.5mm to 5.5mm, and the width W0 of the solder mark ranges from 1.6mm to 3.4mm.

[0015] This utility model also proposes a cylindrical secondary battery, including the above-mentioned cylindrical battery negative electrode current collector welding structure.

[0016] The cylindrical battery negative electrode current collector welding structure and cylindrical secondary battery proposed in this utility model have the following beneficial effects:

[0017] (1) In this welding structure, the ratio of the length L0 of the weld mark to the radius R0 of the negative electrode current collector is set between 37% and 57% to prevent the length L0 of the weld mark from being too large or too small. This ensures the current carrying capacity of the weld mark, reduces the welding defect rate, enhances the reliability of the welding, and thus ensures the performance of the cylindrical secondary battery.

[0018] (2) In this welding structure, the ratio of the radius R1 of the boss to the radius R0 of the disk surface, R1 / R0, is set to 24% to 40%. This prevents the radius R1 of the boss from being too small, which would affect the connection strength between the negative electrode current collector and the battery casing, and also prevents the radius R1 of the boss from being too large, which would compress the length L0 of the weld, thereby ensuring the performance of the cylindrical secondary battery.

[0019] (3) In this welding structure, the ratio of the minimum distance L1 between the weld mark and the boss to the radius R0 of the disk surface is set to 5% to 16%. This prevents the distance between the weld mark and the outer peripheral surface of the boss from being too small, which would increase the welding difficulty between the negative electrode current collector and the core negative electrode. It also prevents the distance between the weld mark and the outer peripheral surface of the boss from being too large, which would compress the length L0 of the weld mark. This improves the production efficiency of the cylindrical secondary battery and ensures the performance of the cylindrical secondary battery.

[0020] (4) In this welding structure, the ratio of the minimum distance L2 between the weld mark and the edge of the disk surface to the radius R0 of the disk surface is set to 5% to 16%. This prevents the minimum distance L2 between the weld mark and the edge of the disk surface from being too small, which would increase the welding difficulty between the negative electrode current collector and the core negative electrode. It also prevents the minimum distance L2 between the weld mark and the edge of the disk surface from being too large, which would compress the minimum distance L1 between the weld mark and the boss or the length L0 of the weld mark. This improves the production efficiency of the cylindrical secondary battery and ensures the performance of the cylindrical secondary battery.

[0021] (5) The weld marks of this welding structure are four symmetrically distributed in a cross shape on the outer periphery of the boss. By welding the negative current collector and the core negative electrode at the four weld marks, the connection strength between the negative current collector and the core negative electrode is enhanced, and the connection force between the negative current collector and the core negative electrode is more uniform, which enhances the reliability of the connection between the negative current collector and the core negative electrode, thereby ensuring the performance of the cylindrical secondary battery.

[0022] (6) Each weld mark of this welding structure includes three weld lines extending radially along the disk surface. At the location of each weld mark, the negative current collector and the core negative electrode are welded through the three weld lines extending radially along the disk surface, which further enhances the connection strength between the negative current collector and the core negative electrode and ensures the performance of the cylindrical secondary battery.

[0023] (7) The welding line of this welding structure is corrugated. Therefore, when the length L0 of the welding mark (i.e. the distance between the two ends of the welding line extending radially along the disk surface) is determined, the corrugated welding line can increase the length of the welding line. Thus, when welding the negative current collector and the core negative electrode through the welding line, the connection strength between the negative current collector and the core negative electrode can be enhanced, ensuring the performance of the cylindrical secondary battery.

[0024] (8) In this welding structure, the included angle B of each corrugation of the welding line is set between 70° and 120°. This prevents the included angle B of each corrugation of the welding line from being too small, which would result in a relatively concentrated heat and poor heat dissipation during welding, thus ensuring the welding quality. It also prevents the included angle B of each corrugation of the welding line from being too large, which would reduce the length of the welding line and thus affect the connection strength between the negative current collector and the core negative electrode, thereby ensuring the performance of the cylindrical secondary battery.

[0025] (9) In this welding structure, the ratio of the width W0 of the weld mark to the radius R0 of the negative electrode current collector is set between 17% and 36%. This prevents the spacing between the three welding lines from being too close, which would result in concentrated heat and poor heat dissipation during welding, thus ensuring welding quality. It also prevents the spacing between the welding lines from increasing the stroke of the welding equipment during welding, which would reduce welding efficiency, thereby improving the production efficiency of cylindrical secondary batteries. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is a schematic diagram of the welding structure of a cylindrical battery negative electrode current collector according to an embodiment of the present utility model;

[0028] Figure 2 This is a schematic diagram of the negative electrode current collector of a cylindrical battery according to an embodiment of the present invention.

[0029] Figure 3 for Figure 1 Enlarged diagram of point A in the middle.

[0030] In the diagram: 1. Negative current collector; 11. Plate surface; 12. Boss; 2. Solder mark; 21. Solder wire. Detailed Implementation

[0031] 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.

[0032] Please see Figures 1-3This utility model discloses a cylindrical battery negative electrode current collector welding structure, including a negative electrode current collector 1 and a solder mark 2 disposed on the negative electrode current collector 1. The negative electrode current collector 1 is used to connect the negative electrode of the winding core to the bottom of the battery casing, and the solder mark 2 is used to connect the negative electrode current collector 1 to the negative electrode of the winding core. The ratio of the length L0 of the solder mark 2 to the radius R0 of the negative electrode current collector 1, L0 / R0, is 37% to 57%.

[0033] In this application, the negative electrode current collector welding structure includes a negative electrode current collector 1, which is disposed inside the battery casing. The negative electrode current collector 1 connects the negative electrode of the wound core, which is loaded inside the battery casing, to the bottom of the battery casing, thereby making the negative electrode of the wound core conductive and allowing the battery casing to draw out the negative electrode of the wound core, thus realizing the discharge of the negative electrode current. The negative electrode current collector 1 is provided with solder marks 2. The connection between the negative electrode current collector 1 and the negative electrode of the wound core is achieved by welding the negative electrode current collector 1 to the location of the solder marks 2.

[0034] In practical use, if the ratio L0 of the length of the solder mark 2 to the radius R0 of the negative electrode current collector 1 is set too small, that is, if the length L0 of the solder mark 2 is too small, the current carrying capacity of the solder mark 2 will be weakened, resulting in greater heat generation in the area where the solder mark 2 is located during current carrying, causing the temperature at the welding point to rise, and the internal resistance of the battery to increase, thereby affecting the performance of the cylindrical secondary battery.

[0035] However, if the ratio L0 of the length of the solder mark 2 to the radius R0 of the negative electrode current collector 1 is set too large, that is, if the length L0 of the solder mark 2 is too large, it will increase the risk of poor welding and reduce the reliability of welding, and will also affect the performance of the cylindrical secondary battery.

[0036] Therefore, in this application, the ratio L0 of the length L0 of the solder mark 2 to the radius R0 of the negative electrode current collector 1, L0 / R0, is set between 37% and 57% to prevent the length L0 of the solder mark 2 from being too large or too small. This ensures both the current carrying capacity of the solder mark 2 and reduces the welding defect rate, enhancing the reliability of the welding and thus guaranteeing the performance of the cylindrical secondary battery. Preferably, in this application, the ratio L0 / R0 can be set to 47%.

[0037] In this embodiment, the negative electrode current collector 1 includes a disk surface 11 and a boss 12 located at the center of the disk surface 11. The boss 12 is used for welding to the battery casing. The solder marks 2 extend radially on the disk surface 11 and are distributed on the outer periphery of the boss 12. The radius R0 of the negative electrode current collector 1 is the radius of the disk surface 11, and the ratio R1 / R0 of the radius R1 of the boss 12 to the radius R0 of the disk surface 11 is 24% to 40%.

[0038] In this application, the negative current collector 1 includes a disk surface 11 and a boss 12. The boss 12 is located at the center of the disk surface 11 and extends vertically upward. The solder mark 2 is located on the disk surface 11 and distributed on the outer periphery of the boss 12. Thus, by welding the negative current collector 1 to the negative electrode of the winding core at the location of the solder mark 2, the negative current collector 1 is connected to the negative electrode of the winding core. The negative current collector 1 is connected to the battery casing by welding the boss 12 to the bottom of the battery casing. Then, the negative current collector 1 conducts the negative electrode of the winding core to the battery casing, so that the battery casing leads out the negative electrode of the winding core, thereby realizing the output of the negative electrode current of the winding core.

[0039] In practice, the boss 12 of the negative electrode current collector 1 is usually welded to the bottom of the battery casing using a through-welding method. If the ratio R1 / R0 of the radius R1 of the boss 12 to the radius R0 of the disk surface 11 is set too small, that is, the radius R1 of the boss 12 is too small, the area of ​​the top plane of the boss 12 will be too small. When the boss 12 is through-welded to the bottom of the battery casing, the effective welding area will be too small, which will reduce the welding strength between the boss 12 and the battery casing, thereby affecting the connection strength between the negative electrode current collector 1 and the battery casing, and consequently affecting the performance of the cylindrical secondary battery.

[0040] If the ratio R1 / R0 of the radius R1 of the boss 12 to the radius R0 of the disk surface 11 is set too large, that is, the radius R1 of the boss 12 is too large, since the solder 2 extends radially on the disk surface 11 and is distributed on the outer periphery of the boss 12, the cross-sectional area of ​​the boss 12 will be too large, which will compress the extension space of the solder 2 on the disk surface 11, thereby reducing the length L0 of the solder 2. This will weaken the current carrying capacity of the solder 2, resulting in greater heat generation in the area where the solder 2 is located during current carrying, and thus affecting the performance of the cylindrical secondary battery.

[0041] Therefore, in this application, the ratio R1 / R0 of the radius R1 of the boss 12 to the radius R0 of the disk surface 11 is set to 24% to 40%. This prevents the radius R1 of the boss 12 from being too small, which would affect the connection strength between the negative electrode current collector 1 and the battery casing, and also prevents the radius R1 of the boss 12 from being too large, which would compress the length L0 of the solder mark 2, thereby ensuring the performance of the cylindrical secondary battery. Preferably, in this application, the ratio R1 / R0 is set to 32%.

[0042] In this embodiment, the ratio L1 of the minimum distance L1 between the solder mark 2 and the boss 12 to the radius R0 of the disk surface 11, L1 / R0, is 5% to 16%. In this application, when the solder mark 2 extending radially on the disk surface 11 is distributed on the outer periphery of the boss 12, it is spaced at a certain distance from the outer peripheral surface of the boss 12.

[0043] In actual implementation, if the ratio L1 / R0 of the minimum distance L1 between the solder mark 2 and the boss 12 to the radius R0 of the disk surface 11 is set too small, that is, the distance between the solder mark 2 and the outer peripheral surface of the boss 12 is too small, it will cause interference with the boss 12 when welding the negative current collector 1 and the core negative electrode at the location of the solder mark 2, thereby increasing the welding difficulty of the negative current collector 1 and the core negative electrode and reducing the production efficiency of the cylindrical secondary battery.

[0044] If the ratio L1 / R0 of the minimum distance L1 between the solder mark 2 and the boss 12 to the radius R0 of the disk surface 11 is set too large, that is, the distance between the solder mark 2 and the outer peripheral surface of the boss 12 is too large, it will also compress the extension space of the solder mark 2 on the disk surface 11, thereby reducing the length of the solder mark 2, which will weaken the current carrying capacity of the solder mark 2, resulting in greater heat generation in the area where the solder mark 2 is located during current carrying, and thus affecting the performance of the cylindrical secondary battery.

[0045] Therefore, in this application, the ratio L1 of the minimum distance L1 between the solder mark 2 and the boss 12 to the radius R0 of the disk surface 11, L1 / R0, is set to 5% to 16%. This prevents the distance between the solder mark 2 and the outer peripheral surface of the boss 12 from being too small, which would increase the welding difficulty between the negative electrode current collector 1 and the core negative electrode, and also prevents the distance between the solder mark 2 and the outer peripheral surface of the boss 12 from being too large, which would compress the length L0 of the solder mark 2. This improves the production efficiency of the cylindrical secondary battery while ensuring its performance. Preferably, in this application, the ratio L1 / R0 is set to 11%.

[0046] In this embodiment, the ratio L2 of the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 to the radius R0 of the disk surface 11, L2 / R0, is 5% to 16%. In this application, since the solder mark 2 extends radially on the disk surface 11, in actual use, if the ratio L2 / R0 of the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 to the radius R0 of the disk surface 11 is set too small, that is, if the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 is too small, it will increase the welding difficulty between the negative electrode current collector 1 and the core negative electrode, thereby reducing the production efficiency of the cylindrical secondary battery.

[0047] If the ratio L2 / R0 of the minimum distance L2 between the solder mark 2 and the edge of the disk 11 to the radius R0 of the disk 11 is set too large, that is, the minimum distance L2 between the solder mark 2 and the edge of the disk 11 is too large, it will either cause the minimum distance L1 between the solder mark 2 and the boss 12 to be too small, which will increase the welding difficulty between the negative current collector 1 and the core negative electrode, thereby reducing the production efficiency of the cylindrical secondary battery; or it will cause the length of the solder mark 2 to be reduced, weakening the current carrying capacity of the solder mark 2, resulting in greater heat generation in the area where the solder mark 2 is located during current carrying, thereby affecting the performance of the cylindrical secondary battery.

[0048] Therefore, in this application, the ratio L2 of the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 to the radius R0 of the disk surface 11 is set to 5% to 16%. This prevents the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 from being too small, which would increase the welding difficulty between the negative electrode current collector 1 and the core negative electrode. It also prevents the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 from being too large, which would compress the minimum distance L1 between the solder mark 2 and the boss 12 or the length L0 of the solder mark 2. This improves both the production efficiency of the cylindrical secondary battery and ensures its performance. Preferably, in this application, the ratio L2 / R0 is set to 11%, meaning L2 and L1 are equal.

[0049] In actual implementation, the radius R0 of the negative electrode current collector 11 is first determined according to the battery casing size of the cylindrical secondary battery. Then, according to the ratios L1 / R0 and L2 / R0 defined in the above embodiment, the range of values ​​for L1 and L2 is obtained, thereby determining the values ​​of L1 and L2, and then determining the position of the solder mark 2 on the disk surface 11.

[0050] In this embodiment, the minimum distance L1 between the solder mark 2 and the boss 12 is set between 0.5mm and 1.5mm, and the minimum distance L2 between the solder mark 2 and the edge of the disk surface 11 is set between 0.5mm and 1.5mm. This further narrows the range of values ​​for L1 and L2 when determining their values, making the values ​​of L1 and L2 more reasonable and ensuring the performance of the cylindrical secondary battery. Preferably, in this application, both L1 and L2 are set to 1mm.

[0051] In this embodiment, the solder marks 2 are four in a cross-shaped symmetrical distribution on the outer periphery of the boss 12. By welding the negative current collector 1 to the core negative electrode at the four solder marks 2, the connection strength between the negative current collector 1 and the core negative electrode is enhanced, and the connection force between the negative current collector 1 and the core negative electrode is more uniform, thereby enhancing the reliability of the connection between the negative current collector 1 and the core negative electrode and ensuring the performance of the cylindrical secondary battery.

[0052] In this embodiment, each solder mark 2 includes three solder lines 21 extending radially along the disk surface 11. At the location of each solder mark 2, the negative electrode current collector 1 and the core negative electrode are welded through the three solder lines 21 extending radially along the disk surface 11, which further enhances the connection strength between the negative electrode current collector 1 and the core negative electrode and ensures the performance of the cylindrical secondary battery.

[0053] It is foreseeable that the length L0 of the solder mark 2 is the distance between the two ends of each solder line 21 extending radially along the disk surface 11. In this application, the solder line 21 is corrugated, so that when the length L0 of the solder mark 2 (i.e., the distance between the two ends of the solder line 21 extending radially along the disk surface 11) is determined, the corrugated solder line 21 can increase the length of the solder line 21. Therefore, when welding the negative current collector 1 to the core negative electrode through the solder line 21, the connection strength between the negative current collector 1 and the core negative electrode can be enhanced, ensuring the performance of the cylindrical secondary battery.

[0054] In actual use, if the included angle B of each corrugation of the welding line 21 is set too small, and the distance between the two ends of the welding line 21 extending radially along the disk surface 11 is fixed, it will result in too many corrugations of the welding line 21, which will lead to the spacing between adjacent corrugations being too close. Consequently, when welding the negative electrode current collector 1 and the core negative electrode at the location of the welding mark 2, the heat will be relatively concentrated, the heat dissipation will be poor, and welding defects such as welding explosions and weld burn-through will easily occur.

[0055] If the included angle B of each corrugation of the bonding wire 21 is set too large, and the distance between the two ends of the bonding wire 21 extending radially along the disk surface 11 is fixed, the number of corrugations of the bonding wire 21 will be too small, thereby reducing the length of the bonding wire 21 and affecting the connection strength between the negative current collector 1 and the core negative electrode.

[0056] Therefore, in this application, the included angle B of each corrugation of the welding wire 21 is set between 70° and 120°. This prevents the included angle B of each corrugation of the welding wire 21 from being too small, which would lead to concentrated heat and poor heat dissipation during welding, thus ensuring welding quality. Conversely, it prevents the included angle B of each corrugation of the welding wire 21 from being too large, which would reduce the length of the welding wire 21 and affect the connection strength between the negative electrode current collector 1 and the core negative electrode, thereby ensuring the performance of the cylindrical secondary battery. Preferably, in this application, the included angle B of each corrugation of the welding wire 21 is set to 95°.

[0057] In this embodiment, the ratio W0 of the width of the solder mark 2 to the radius R0 of the negative current collector 1 is 17% to 36%. As mentioned in the previous embodiment, each solder mark 2 includes three solder lines 21 extending radially along the disk surface 11, therefore the width W0 of the solder mark 2 is the overall width of the three solder lines 21.

[0058] In actual use, if the ratio W0 / R0 of the width W0 of the solder mark 2 to the radius R0 of the negative current collector 1 is set too small, that is, if the width W0 of the solder mark 2 is too small, the spacing between the three welding lines 21 will be too close. As a result, when welding the negative current collector 1 to the negative electrode of the core at the location of the solder mark 2, the heat will be concentrated and the heat dissipation will be poor, which will easily cause welding defects such as welding explosions and weld burn-through.

[0059] If the ratio W0 / R0 of the width W0 of the solder mark 2 to the radius R0 of the negative electrode current collector 1 is set too large, that is, the width W0 of the solder mark 2 is set too large, it will cause the spacing between the three welding lines 21 to be too far. As a result, when welding the negative electrode current collector 1 to the core negative electrode at the location of the solder mark 2, the stroke of the welding equipment will be increased, the welding efficiency will be reduced, and thus the production efficiency will be reduced.

[0060] Therefore, in this application, the ratio W0 of the width W0 of the solder mark 2 to the radius R0 of the negative electrode current collector 1 is set between 17% and 36%. This prevents the spacing between the three solder lines 21 from being too close, which would result in concentrated heat and poor heat dissipation during welding, thus ensuring welding quality. It also prevents the spacing between the three solder lines 21 from being too far, which would increase the stroke of the welding equipment and reduce welding efficiency, thereby improving the production efficiency of the cylindrical secondary battery. Preferably, in this application, the ratio W0 / R0 is set to 26%.

[0061] In actual implementation, the radius R0 of the negative electrode current collector 11 is first determined according to the battery casing size of the cylindrical secondary battery. Then, according to the ratios L0 / R0 and W0 / R0 defined in the above embodiment, the range of values ​​for L0 and W0 is obtained, thereby determining the values ​​of L0 and W0, and then determining the length and width of the solder mark 2.

[0062] In this embodiment, the length L0 of the solder mark 2 is set between 3.5mm and 5.5mm, and the width W0 of the solder mark 2 is set between 1.6mm and 3.4mm. This further narrows the range of values ​​for L0 and W0 when determining their values, making the values ​​of L0 and W0 more reasonable and ensuring the performance of the cylindrical secondary battery. Preferably, in this application, the length L0 of the solder mark 2 is set to 4.5mm, and the width W0 of the solder mark 2 is set to 2.5mm.

[0063] This utility model embodiment also provides a cylindrical secondary battery, including the above-described negative electrode current collector welding structure.

[0064] 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.

[0065] 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.

[0066] 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 welding structure for the negative electrode current collector of a cylindrical battery, characterized in that: The device includes a negative electrode current collector (1) and a solder mark (2) disposed on the negative electrode current collector (1). The negative electrode current collector (1) is used to connect the negative electrode of the winding core to the bottom of the battery casing. The solder mark (2) is used to connect the negative electrode current collector (1) to the negative electrode of the winding core. The ratio of the length L0 of the solder mark (2) to the radius R0 of the negative electrode current collector (1), L0 / R0, is 37% to 57%.

2. The cylindrical battery negative electrode current collector welding structure as described in claim 1, characterized in that: The negative electrode current collector (1) includes a disk surface (11) and a boss (12) located at the center of the disk surface (11). The boss (12) is used for welding to the battery casing. The solder mark (2) extends radially on the disk surface (11) and is distributed on the outer periphery of the boss (12). The radius R0 of the negative electrode current collector (1) is the radius of the disk surface (11), and the ratio R1 of the radius R1 of the boss (12) to the radius R0 of the disk surface (11) is 24% to 40%.

3. The cylindrical battery negative electrode current collector welding structure as described in claim 2, characterized in that: The minimum distance L1 between the solder mark (2) and the boss (12) is 5% to 16% of the ratio L1 / R0 to the radius R0 of the disk surface (11).

4. The cylindrical battery negative electrode current collector welding structure as described in claim 3, characterized in that: The minimum distance L2 between the solder mark (2) and the edge of the disk surface (11) is 5% to 16% of the ratio L2 / R0 to the radius R0 of the disk surface (11).

5. The cylindrical battery negative electrode current collector welding structure as described in claim 4, characterized in that: The minimum distance L1 between the solder mark (2) and the boss (12) is 0.5mm to 1.5mm, and the minimum distance L2 between the solder mark (2) and the edge of the disk surface (11) is 0.5mm to 1.5mm.

6. The cylindrical battery negative electrode current collector welding structure as described in claim 2, characterized in that: The solder marks (2) are distributed in a cross-shaped symmetrical pattern on the outer periphery of the boss (12).

7. The cylindrical battery negative electrode current collector welding structure as described in claim 6, characterized in that: Each of the solder marks (2) includes multiple solder lines (21) extending radially along the disk surface (11), the solder lines (21) being corrugated, and the included angle B of each corrugation of the solder line (21) being 70° to 120°.

8. A cylindrical battery negative electrode current collector welding structure as described in any one of claims 1-7, characterized in that: The ratio of the width W0 of the solder mark (2) to the radius R0 of the negative electrode current collector (1), W0 / R0, is 17% to 36%.

9. The cylindrical battery negative electrode current collector welding structure as described in claim 8, characterized in that: The length L0 of the solder mark (2) ranges from 3.5mm to 5.5mm, and the width W0 of the solder mark (2) ranges from 1.6mm to 3.4mm.

10. A cylindrical secondary battery, characterized in that, Including a cylindrical battery negative electrode current collector welding structure as described in any one of claims 1-9.

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