A cylindrical secondary battery

Abstract

This utility model proposes a cylindrical secondary battery, including a positive electrode current collector and a negative electrode current collector. The positive electrode current collector includes a disk body and a tail body. The disk body is provided with multiple positive electrode welding areas. The area of ​​the disk body is S1, and the sum of the areas of the multiple positive electrode welding areas is S2. 100 12%S1≤S 100 ≤24%S1; The negative electrode current collector is provided with multiple negative electrode welding areas, and each negative electrode welding area is provided with multiple negative electrode solder marks. The area of ​​the negative electrode current collector is S2, and the sum of the areas of the multiple negative electrode welding areas is S. 200 Among them, 10%S²≤S 200 ≤20%S2. This utility model, by setting a positive electrode welding area and a positive electrode solder mark on the positive electrode current collector, and setting a negative electrode welding area and a negative electrode solder mark on the negative electrode current collector, and by reasonably setting the area of ​​the positive electrode welding area and the negative electrode welding area, can take into account the battery's overcurrent capacity as well as the battery's processing quality and processing efficiency, thereby effectively improving the overall performance of the battery.

Description

Technical Field

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

[0002] With the continuous development of new energy technologies, batteries, as high-efficiency energy storage devices, are widely used in various portable electronic products, electric vehicles, and large-scale energy storage systems. Among them, cylindrical secondary batteries have gradually become one of the mainstream products in the market due to their excellent performance and high energy density.

[0003] Welding, as a reliable connection method, can provide strong mechanical strength and enable the two welded components to conduct electricity. In the assembly process of cylindrical secondary batteries, laser welding or ultrasonic welding is used to fix the positive current collector and negative current collector to the positive and negative tabs of the core respectively, so as to ensure the performance stability and safety of the battery.

[0004] For example, the utility model disclosed in CN220895786U discloses a positive current collector, a negative current collector, and a cylindrical battery with all tabs. The positive current collector has positive welding patterns, and the negative current collector has negative welding patterns, which are then fixed to the positive and negative tabs of the core, respectively. However, if the area of ​​the welding patterns is too small, the corresponding welding area decreases, the battery's internal resistance increases, and the current-carrying capacity of the corresponding welding wire weakens, leading to an increase in temperature at the welding wire and consequently, the battery's temperature, which affects battery performance. If the area of ​​the welding patterns is too large, it not only fails to improve the battery's internal resistance but also increases the length of the welding wire, increasing the welding time and reducing welding efficiency. Simultaneously, an excessively large welding pattern area also increases the risk of welding defects, increasing the defect rate, increasing battery manufacturing costs, reducing battery manufacturing efficiency, and affecting the overall performance of the battery. Utility Model Content

[0005] In view of this, the present invention proposes a cylindrical secondary battery. By reasonably setting the area ratio of the positive electrode welding area and the negative electrode welding area, the battery's overcurrent capacity, processing quality, and processing efficiency can be balanced, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is implemented as follows: This utility model provides a cylindrical secondary battery, including a positive electrode current collector and a negative electrode current collector, wherein,

[0007] The positive electrode current collector includes a disk body and a tail body. The disk body has multiple positive electrode welding areas, and each positive electrode welding area has multiple positive electrode solder marks. The disk body and the positive electrode lug of the winding core are welded and fixed together by the positive electrode solder marks. The area of ​​the disk body is S1, and the sum of the areas of the multiple positive electrode welding areas is S. 100Among them, 12%S1≤S 100 ≤24%S1;

[0008] The negative electrode current collector has multiple negative electrode welding areas, and each negative electrode welding area has multiple negative electrode solder marks. The negative electrode current collector is welded and fixed to the negative electrode lug of the winding core through the negative electrode solder marks. The area of ​​the negative electrode current collector is S2, and the sum of the areas of the multiple negative electrode welding areas is S. 200 Among them, 10%S²≤S 200 ≤20%S2.

[0009] Based on the above technical solution, preferably, both the positive electrode welding area and the negative electrode welding area are rectangular, and the area of ​​each positive electrode welding area is S. 10 The area of ​​each of the negative electrode welding regions is S. 20 Among them, 3%S1≤S 10 ≤6%S1, 3%S2≤S 20 ≤5%S2.

[0010] Even more preferably, 4%S1≤S 10 ≤5%S1, 16%S1≤S 100 ≤20%S1.

[0011] Based on the above technical solution, preferably, the length of the positive electrode welding area is L. 10 The width of the positive electrode welding area is W. 10 The length of the negative electrode welding area is L. 20 The width of the negative electrode welding area is W. 20 Where 4mm≤L 10 ≤6mm, 2mm≤W 10 ≤3mm, 3.5mm≤L 20 ≤5.5mm, 1.6mm≤W 20 ≤3.4mm.

[0012] More preferably, the positive electrode solder mark is curved, and multiple positive electrode solder marks located in the same positive electrode welding area are arranged in parallel and spaced apart;

[0013] The distance between the opposite sides of two adjacent positive electrode solder marks is W. 12 Of which, 12% W 10 ≤W 12 ≤22%W 10 .

[0014] More preferably, the span of the positive electrode solder mark along the width direction of the positive electrode welding area is W. 11 Of which, 17% W 10 ≤W11 ≤27% W 10 .

[0015] More preferably, the negative electrode solder mark is curved, and multiple negative electrode solder marks located in the same negative electrode welding area are arranged in parallel and spaced apart;

[0016] The spacing between two adjacent negative electrode solder marks is W. 22 Where 0.6mm≤W 22 ≤1.1mm.

[0017] More preferably, the span of the negative electrode solder mark along the width direction of the negative electrode welding area is W. 21 The width of the negative electrode solder mark is W. 23 Where, 0.15mm≤(W 21 -W 23 )≤0.35mm, 0.1mm≤W 23 ≤0.3mm, and W 23 <W 22 .

[0018] Based on the above technical solutions, preferably, the positive electrode soldering includes multiple positive electrode straight soldering lines and multiple positive electrode arc soldering lines, wherein the multiple positive electrode straight soldering lines and multiple positive electrode arc soldering lines are arranged alternately and continuously, combined into a wavy line shape, and the angle between one of the positive electrode straight soldering lines and the two adjacent positive electrode straight soldering lines is A and B, respectively, wherein 50°≤A≤75°, 50°≤B≤75°;

[0019] The negative electrode solder mark includes multiple negative electrode straight solder lines and multiple negative electrode arc solder lines, wherein the multiple negative electrode straight solder lines and multiple negative electrode arc solder lines are arranged alternately and continuously, combined into a wavy line shape, and the angle between one of the negative electrode straight solder lines and the two adjacent negative electrode straight solder lines is C and D, respectively, wherein 70°≤C≤120° and 70°≤D≤120°.

[0020] Based on the above technical solutions, preferably, the disk body is provided with a central hole and a peripheral hole, and the positive electrode welding area is spaced apart from the central hole and the peripheral hole;

[0021] The negative electrode current collector has a protrusion in the middle, which is used to weld and fix it to the battery casing. There are four negative electrode welding areas, which are arranged in a circular array around the center point of the protrusion.

[0022] The radius of the disk body is R1, and the radius of the negative electrode current collector is R2, wherein 8.5mm≤R1≤9.6mm and 8.5mm≤R2≤10.5mm.

[0023] The cylindrical secondary battery of this invention has the following advantages over the prior art:

[0024] (1) By setting a positive electrode welding area and a positive electrode solder mark on the positive electrode current collector, and setting a negative electrode welding area and a negative electrode solder mark on the negative electrode current collector, and by reasonably setting the area of ​​the positive electrode welding area and the negative electrode welding area, the overcurrent capacity of the battery and the processing quality and processing efficiency of the battery can be taken into account, thereby effectively improving the overall performance of the battery.

[0025] (2) By setting wavy positive and negative electrode solder marks, the length of the positive and negative electrode solder marks can be increased, thereby improving the welding reliability and current carrying capacity of the positive and negative current collectors.

[0026] (3) By limiting the location and specifications of the positive electrode soldering and negative electrode soldering, the welding quality and current carrying capacity of the positive electrode current collector and negative electrode current collector can be further guaranteed, so as to improve the overall performance of the battery. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a top view of the positive electrode current collector in a cylindrical secondary battery according to the present invention.

[0029] Figure 2 This is a top view of the positive electrode solder joint in a cylindrical secondary battery according to this utility model.

[0030] Figure 3 This is a top view of the negative electrode current collector in a cylindrical secondary battery according to this utility model.

[0031] Figure 4 This is a top view of the negative electrode solder joint in a cylindrical secondary battery according to this utility model.

[0032] Figure 5 This is a front view of the winding core in a cylindrical secondary battery according to the present invention.

[0033] Among them: 1. Positive current collector; 11. Disc body; 12. Tail body; 101. Positive welding area; 102. Positive welding mark; 1021. Positive straight welding line; 1022. Positive arc welding line; 103. Center hole; 104. Peripheral hole; 2. Negative current collector; 21. Boss; 201. Negative welding area; 202. Negative welding mark; 2021. Negative straight welding line; 2022. Negative arc welding line; 3. Core. Detailed Implementation

[0034] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0035] Cylindrical secondary batteries, also known as cylindrical rechargeable batteries, are an important type of battery. They have advantages such as high safety, high energy density, and good charge and discharge performance, and are widely used in electric vehicles, electric two-wheelers, power tools, and other fields.

[0036] This utility model discloses a cylindrical secondary battery comprising a positive electrode current collector 1 and a negative electrode current collector 2, such as... Figure 5 As shown, the positive current collector 1 and the negative current collector 2 are welded and fixed to the positive and negative tabs of the core 3, respectively. The side of the positive current collector 1 away from the core 3 is welded and fixed to the cap assembly, and the side of the negative current collector 2 away from the core 3 is welded and fixed to the bottom side of the battery casing, thereby realizing the conduction of current.

[0037] like Figure 1 As shown, the positive electrode current collector 1 includes a plate body 11 and a tail body 12. The plate body 11 is provided with multiple positive electrode welding areas 101, and each positive electrode welding area 101 is provided with multiple positive electrode solder marks 102. The plate body 11 and the positive electrode ear of the core 3 are welded and fixed by the positive electrode solder marks 102. The welding head welds and fixes the plate body 11 and the core 3 by using the positive electrode solder marks 102 as the welding path. One end of the tail body 12 is integrally formed on the periphery of the plate body 11, and the other end is used to weld and fix it to the cap assembly. During the battery assembly process, the tail body 12 needs to be bent.

[0038] The positive electrode welding area 101 refers to the position on the disk 11 that is connected to the core 3 via the positive electrode solder mark 102, such as... Figure 1As shown, the area within the dashed frame on the disk 11 represents one of the positive electrode welding areas 101. Multiple positive electrode solder marks 102 are closely arranged within the positive electrode welding area 101, and these solder marks 102 completely fill the positive electrode welding area 101. Since the positive electrode welding area 101 is not actually visible, it is only shown in the image. Figure 1 The image shows a positive electrode welding area 101.

[0039] like Figure 3 As shown, the negative electrode current collector 2 has multiple negative electrode welding areas 201, and each negative electrode welding area 201 has multiple negative electrode solder marks 202. The negative electrode current collector 2 and the negative electrode lug of the core 3 are welded and fixed together through the negative electrode solder marks 202. Similarly, the welding head uses the negative electrode solder marks 202 as the welding path to weld and fix the negative electrode current collector 2 and the core 3 together. The negative electrode welding area 201 refers to the position on the negative electrode current collector 2 that is connected to the core 3 through the negative electrode solder marks 202. Figure 3 The area within the dashed box on the negative electrode current collector 2 represents one of the negative electrode welding areas 201. Multiple closely arranged negative electrode solder marks 202 are present within the negative electrode welding area 201, and these solder marks 202 completely fill the negative electrode welding area 201. Since the negative electrode welding area 201 is not actually visible, it is only shown in the image. Figure 3 The image shows a negative electrode welding area 201.

[0040] Preferably, the positive electrode solder mark 102 is curved. Within the same span, the curved positive electrode solder mark 102 has a longer length, which can improve the welding effect and reduce the space occupied by the welding position on the disk body 11. In order to improve the uniformity of the welding position and reduce the welding processing difficulty, it is preferable that multiple positive electrode solder marks 102 located in the same positive electrode welding area 101 are arranged in parallel and spaced apart. Similarly, the negative electrode solder mark 202 is also curved, and multiple negative electrode solder marks 202 located in the same negative electrode welding area 201 are also arranged in parallel and spaced apart.

[0041] like Figure 1 As shown, the disk body 11 has a central hole 103 and multiple peripheral holes 104. The central hole 103 is used to inject electrolyte into the core 3, and the gas generated in the core can be discharged to the cap assembly through the central hole 103. The central hole 103 is located in the middle of the disk body 11. The peripheral holes 104 are also used to allow the gas generated in the core to pass through. Their inner diameter is smaller than that of the central hole 103, and the peripheral holes 104 are located on the periphery of the disk body 11. Multiple peripheral holes 104 are arranged in a circumferential array around the center point of the central hole 103. The positive electrode welding area 101 is spaced apart from the central hole 103 and the peripheral holes 104. Preferably, the positive electrode welding area 101 and the peripheral holes 104 are alternately arranged.

[0042] A boss 21 is provided in the middle of the negative electrode current collector 2. The boss 21 protrudes to the bottom side of the negative electrode current collector 2 for welding and fixing to the battery casing, such as... Figure 3 As shown, there are four negative electrode welding areas 201, which are arranged in a circular array around the center point of the boss 21 to maintain the stability of the welding position on the negative electrode current collector 2.

[0043] like Figure 1 and Figure 3 As shown, the positive electrode welding region 101 and the negative electrode welding region 201 are preferably rectangular, and the length of the positive electrode welding region 101 is L. 10 The width of the positive electrode welding area 101 is W. 10 The area of ​​the disk 11 is S1, and the area of ​​each positive electrode welding area 101 is S. 10 The sum of the areas of the multiple positive electrode welding regions 101 is S. 100 The length of the negative electrode welding area 201 is L. 20 The width of the negative electrode welding area 201 is W. 20 The area of ​​the negative electrode current collector 2 is S2, and the area of ​​each negative electrode welding area 201 is S. 20 The sum of the areas of the multiple negative electrode welding regions 201 is S. 200 .

[0044] In some embodiments, 12%S1≤S 100 ≤24%S1, and 10%S2≤S 200 ≤20%S2, that is, the sum of the areas of multiple positive electrode welding areas 101 is 12%, 18% or 24% of the area of ​​the disk 11, etc., and the sum of the areas of multiple negative electrode welding areas 201 is 10%, 15% or 20% of the area of ​​the negative electrode current collector 2, etc.

[0045] If S 100 If S1 < 12%, the area of ​​the positive electrode welding region 101 is too small, which will reduce the welding strength of the disk 11. To ensure the welding strength, the positive electrode solder mark 102 needs to be increased, resulting in a decrease in welding processing efficiency. At the same time, if the area of ​​the positive electrode welding region 101 is too small, it will also lead to problems such as high internal resistance and concentrated heat generation at the welding position. The current flow area at the welding position is small, the current flow capacity is weakened, and the temperature rise at the welding position is increased, affecting the performance of the battery. If S 100If the area of ​​the positive electrode welding area 101 is greater than 24%, the area of ​​the positive electrode welding area 101 will be too large. The positive electrode welding area 101 is prone to deviating to the position on the disk 11 where welding is not required. This will not only waste welding materials, but also increase welding costs. At the same time, the large area of ​​the positive electrode welding area 101 will not improve the internal resistance of the battery well, but will cause the heat at the welding position to be concentrated and unable to dissipate quickly. This will make the welding position prone to problems such as welding explosion and color change at the welding position due to heat concentration.

[0046] Similarly, if S 200 If S2 < 10%, the area of ​​the negative electrode welding region 201 is too small, which will reduce the welding strength of the negative electrode current collector 2. To ensure the weld strength, the negative electrode solder mark 202 needs to be increased, resulting in a decrease in welding processing efficiency. At the same time, if the area of ​​the negative electrode welding region 201 is too small, it will also lead to problems such as high internal resistance and concentrated heat generation at the welding position. The current flow area at the welding position is small, the current flow capacity is weakened, and the temperature rise at the welding position is increased, affecting the battery performance; if S 200 If the area of ​​the negative electrode welding area 201 is greater than 20%, the area of ​​the negative electrode welding area 201 will be too large. The negative electrode welding area 201 is prone to deviating to the position on the negative electrode current collector 2 where welding is not required. This will not only waste welding materials, but also increase welding costs. At the same time, the excessively large area of ​​the negative electrode welding area 201 will not improve the internal resistance of the battery well, but will cause the heat at the welding position to be concentrated and unable to dissipate quickly. This will make the welding position prone to problems such as welding explosion and color change at the welding position due to heat concentration.

[0047] In some embodiments, 3%S1≤S 10 ≤6%S1, 3%S2≤S 20 ≤5%S2, meaning the area of ​​each positive electrode welding region 101 is 3%, 4.5%, or 6% of the area of ​​the disk 11, etc., and the area of ​​each negative electrode welding region 201 is 3%, 4%, or 5% of the area of ​​the negative electrode current collector 2, etc. If S 10 <3%S1,S 20 <3% S2, or S 10 >6%S1, S 20 The same problem will occur if the concentration is greater than 5% S2.

[0048] Furthermore, it is preferable to let 4%S1≤S 10 ≤5%S1, 16%S1≤S 100 ≤20%S1, meaning that the area of ​​each positive electrode welding area 101 is 4%, 4.5%, or 5% of the area of ​​the disk 11, and the sum of the areas of multiple positive electrode welding areas 101 is 16%, 18%, or 20% of the area of ​​the disk 11.

[0049] In some embodiments, 4mm≤L 10≤6mm, 2mm≤W 10 ≤3mm, 3.5mm≤L 20 ≤5.5mm, 1.6mm≤W 20 ≤3.4mm, meaning the length of the positive electrode welding area 101 is 4mm, 5mm, or 6mm, etc., and the width of the positive electrode welding area 101 is 2mm, 2.5mm, or 3mm, etc.; the length of the negative electrode welding area 201 is 3.5mm, 4.5mm, or 5.5mm, etc., and the width of the negative electrode welding area 201 is 1.6mm, 2.5mm, or 3.4mm, etc. If L 10 If the length of the positive electrode welding area 101 is less than 4mm, it will not only reduce the welding strength of the disk 11, but also increase the internal resistance at the welding position, causing concentrated heat generation at the welding position and resulting in excessive rate-controlled temperature rise; for example, L 10 If the length is greater than 6mm, the positive electrode welding area 101 is too long and may deviate from the weldable area on the disk 11, resulting in waste of welding materials, increased welding process cycle, and higher welding costs. If L 20 If the length is less than 3.5mm, the length of the negative electrode welding area 201 will be too small. This will not only reduce the welding strength of the negative electrode current collector 2, but also increase the internal resistance at the welding position, causing concentrated heat generation at the welding position and resulting in excessive rate-controlled temperature rise. For example, L... 20 If the length is greater than 5.5mm, the length of the negative electrode welding area 201 is too large, and it is easy to deviate from the weldable area on the negative electrode current collector 2. This will not only waste welding materials, but also increase the welding process cycle and increase welding costs.

[0050] If W 10 If the width is less than 2mm, the positive electrode welding area 101 will be too small, which will not only reduce the welding strength of the disk 11, but also cause concentrated heat generation at the welding position, resulting in excessive rate-controlled temperature rise; if W 10 If the width is greater than 3mm, the width of the positive electrode welding area 101 will be too large, easily deviating from the weldable area on the disk 11. Simultaneously, it will also lead to problems such as uneven current distribution at the welding position. If W 20 If the width is less than 1.6mm, the width of the negative electrode welding area 201 is small, and multiple negative electrode solder marks 202 are excessively concentrated. This leads to concentrated heat generation during welding, making it prone to welding defects such as burn-through and spalling, increasing the welding failure rate. If W 20 If the width is greater than 3.4mm, the width of the negative electrode welding area 201 will be too large, and the spacing between multiple negative electrode solder marks 202 will be too large. This will increase the stroke of the welding head during welding and reduce welding efficiency.

[0051] like Figure 2 As shown, the span of the positive electrode solder mark 102 along the width direction of the positive electrode welding area 101 is W. 11 The distance between the opposite sides of two adjacent positive electrode solder marks 102 is W.12 ,like Figure 4 As shown, the span of the negative electrode solder mark 202 along the width direction of the negative electrode welding area 201 is W. 21 The spacing between two adjacent negative electrode solder marks 202 is W. 22 The width of the negative electrode solder mark 202 is W. 23 .

[0052] In some embodiments, 12% W 10 ≤W 12 ≤22% W 10 That is, the spacing between the opposite sides of two adjacent positive electrode solder marks 102 is 12%, 17%, or 22% of the width of the positive electrode soldering area 101, etc. If W 12 <12% W 10 If the spacing between the opposite sides of two adjacent positive electrode solder marks 102 is too small, the heat generated during welding will be concentrated, causing welding defects such as burn-through and affecting the connection strength at the welding position; if W 12 >22% W 10 If the positive electrode solder mark 102 deviates from the solderable area on the disk 11, it will not only affect the structural strength of the soldering position, but also cause uneven overcurrent at the soldering position, affecting the performance of the battery.

[0053] In some embodiments, 17% W 10 ≤W 11 ≤27% W 10 That is, the span of the positive electrode solder mark 102 along the width direction of the positive electrode welding area 101 is 17%, 22%, or 27% of the width of the positive electrode welding area 101, etc. If W 11 <17% W 10 If the span of the positive electrode solder mark 102 along the width direction of the positive electrode welding area 101 is too small, it will not only result in low welding strength during welding, but also lead to excessive rate-induced temperature rise; if W 11 >27%W 10 If the span of the positive electrode solder mark 102 along the width direction of the positive electrode welding area 101 is too large, the positive electrode solder mark 102 is prone to deviating from the weldable area on the disk body 11, which will not only affect the structural strength of the welding position, but also cause uneven overcurrent at the welding position, affecting the performance of the battery.

[0054] In some embodiments, 0.6mm≤W 22 ≤1.1mm, meaning the spacing between two adjacent negative electrode solder marks 202 is 0.6mm, 0.8mm, or 1.1mm, etc. If W 22 If the distance between two adjacent negative electrode solder marks (202) is less than 0.6mm, the heat generated during welding will be concentrated, and welding defects such as spalls may occur at the welding position; if W 22If the distance is greater than 1.1mm, the spacing between two adjacent negative electrode solder marks 202 is too large. During the welding operation, the stroke of the welding head is too large, which will reduce the welding efficiency. At the same time, the excessively large spacing between two adjacent negative electrode solder marks 202 will also reduce the welding firmness between the negative electrode current collector 2 and the core 3.

[0055] In some embodiments, 0.15mm ≤ (W 21 -W 23 )≤0.35mm, 0.1mm≤W 23 ≤0.3mm, and W 23 <W 22 That is, the width of the negative electrode solder mark 202 is less than the spacing between two adjacent negative electrode solder marks 202. The difference between the span of the negative electrode solder mark 202 along the width direction of the negative electrode welding area 201 and the width of the negative electrode solder mark 202 is 0.15mm, 0.25mm or 0.35mm, etc., and the width of the negative electrode solder mark 202 is 0.1mm, 0.2mm or 0.3mm, etc.

[0056] If (W) 21 -W 23 If the thickness is less than 0.15mm, the internal height of the raised portion of a single negative electrode solder mark 202 is too small, and the distance between two adjacent negative electrode solder marks 202 is very close. This results in concentrated heat during welding, making defects such as welding spalls more likely. 21 -W 23 If the height of the protruding part of a single negative electrode solder mark 202 is greater than 0.35mm, the distance between two adjacent negative electrode solder marks 202 will be too large, which will increase the stroke of the welding head and reduce the welding efficiency during welding.

[0057] If W 23 If the weld width is less than 0.1mm, the weld width of the negative electrode solder mark 202 is too small, weakening the current carrying capacity and causing an increase in temperature at the soldering position, thus affecting the battery performance; if W 23 If the weld width is greater than 0.3mm, the weld width of the negative electrode solder mark 202 will be too large, which will have little effect on improving the internal resistance of the battery, but will increase the welding area, making it easy for welding defects to occur and affecting the welding reliability.

[0058] like Figure 2 As shown, the positive electrode solder mark 102 includes multiple positive electrode straight solder lines 1021 and multiple positive electrode arc solder lines 1022. The multiple positive electrode straight solder lines 1021 and multiple positive electrode arc solder lines 1022 are alternately and continuously arranged, forming a wavy positive electrode solder mark 102. Similarly, as... Figure 4As shown, the negative electrode solder mark 202 includes multiple negative electrode straight welding lines 2021 and multiple negative electrode arc welding lines 2022. The multiple negative electrode straight welding lines 2021 and multiple negative electrode arc welding lines 2022 are alternately and continuously arranged, forming a wavy negative electrode solder mark 202. With the same span, the wavy positive electrode solder mark 102 and the negative electrode solder mark 202 are longer, thus providing better welding quality and connection performance.

[0059] like Figure 2 and Figure 4 As shown, the angles between one of the positive electrode straight bonding wires 1021 and the two adjacent positive electrode straight bonding wires 1021 are A and B, respectively, and the angles between one of the negative electrode straight bonding wires 2021 and the two adjacent negative electrode straight bonding wires 2021 are C and D, respectively.

[0060] In some embodiments, 50°≤A≤75°, 50°≤B≤75°, 70°≤C≤120°, 70°≤D≤120°, preferably A=B, C=D. If A<50°, the spacing between two adjacent positive electrode straight bonding lines 1021 is too small, resulting in increased heat during welding and a tendency for welding explosions, affecting welding quality. When A>75°, the spacing between two adjacent positive electrode straight bonding lines 1021 is too small, reducing the total length of the positive electrode solder mark 102, which reduces the current flow performance at the welding position and leads to increased temperature rise. To ensure the total length of the positive electrode solder mark 102, the length of the positive electrode welding area 101 needs to be increased, causing the welding position to exceed the weldable area on the disk 11. Similarly, if C < 70°, the spacing between two adjacent negative electrode straight welding lines 2021 is too small, which increases the heat during welding and easily leads to welding explosions and other problems, affecting the welding quality. When C > 120°, the spacing between two adjacent negative electrode straight welding lines 2021 is too small, and the total length of the negative electrode solder mark 202 is reduced, which will reduce the current flow performance at the welding position and cause the temperature to rise. If the total length of the negative electrode solder mark 202 is to be guaranteed, the length of the negative electrode welding area 201 needs to be increased, which causes the welding position to exceed the weldable area on the negative electrode current collector 2.

[0061] like Figure 1 and Figure 3 As shown, the radius of disk 11 is R1, and the radius of negative current collector disk 2 is R2.

[0062] In some embodiments, 8.5mm≤R1≤9.6mm and 8.5mm≤R2≤10.5mm are used to accommodate commonly used cylindrical secondary batteries.

[0063] In some embodiments, R1 = 9.1 mm, S 10 =4.4%S1,S 100 =18%S1,L 10 =5mm, W10 =2.3mm, W 12 =17% W 10 W 11 =22% W 10 , A=B=60°, R2=9.5mm, S 20 =4%S2,S 200 =16%S2,L 20 =4.5mm, W 20 =2.5mm, W 22 =0.8mm, (W 21 -W 23 ) = 0.26mm, W 23 =0.2mm, C=D=95°, at this point, the battery's overcurrent capacity, processing quality, and processing efficiency can be balanced, thereby effectively improving the overall performance of the battery.

[0064] The working principle of the cylindrical secondary battery of this utility model is as follows:

[0065] A wavy positive electrode solder mark 102 welds and fixes the disc body 11 to the positive electrode tab of the core 3, and a wavy negative electrode solder mark 202 welds and fixes the negative electrode current collector 2 to the negative electrode tab of the core 3. The tail body 12 is welded and fixed to the battery cap assembly, and the boss 21 is welded and fixed to the bottom of the battery casing, thereby making the cap assembly positively charged and the casing negatively charged, realizing the transfer of current. By reasonably limiting the size of the positive electrode solder mark 102 and the negative electrode solder mark 202, the battery's current carrying capacity, as well as the battery's processing quality and efficiency, can be balanced, thereby effectively improving the overall performance of the battery.

[0066] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cylindrical secondary battery, characterized in that: It includes a positive current collector (1) and a negative current collector (2), wherein, The positive current collector disc (1) comprises a disc body (11) and a tail body (12), a plurality of positive electrode welding areas (101) are arranged on the disc body (11), a plurality of positive electrode welding spots (102) are arranged in each positive electrode welding area (101), the disc body (11) and the positive electrode lug of the winding core (3) are welded and fixed through the positive electrode welding spots (102), the area of the disc body (11) is S1, and the sum of the areas of the plurality of positive electrode welding areas (101) is S 100 Wherein, 12% S1≤S 100 ≤24% S1; The negative electrode current collector (2) is provided with multiple negative electrode welding areas (201), and each negative electrode welding area (201) is provided with multiple negative electrode solder marks (202). The negative electrode current collector (2) and the negative electrode lug of the core (3) are welded and fixed by the negative electrode solder marks (202). The area of ​​the negative electrode current collector (2) is S2, and the sum of the areas of the multiple negative electrode welding areas (201) is S. 200 Among them, 10%S²≤S 200 ≤20%S2.

2. The cylindrical secondary battery as described in claim 1, characterized in that: Both the positive electrode welding region (101) and the negative electrode welding region (201) are rectangular, and the area of ​​each positive electrode welding region (101) is S. 10 The area of ​​each of the negative electrode welding regions (201) is S. 20 Among them, 3%S1≤S 10 ≤6%S1, 3%S2≤S 20 ≤5%S2.

3. A cylindrical secondary battery as described in claim 2, characterized in that: 4%S1≤S 10 ≤5%S1,16%S1≤S 100 ≤20%S1.

4. A cylindrical secondary battery as described in claim 1, characterized in that: The length of the positive electrode welding region (101) is L. 10 The width of the positive electrode welding area (101) is W. 10 The length of the negative electrode welding area (201) is L. 20 The width of the negative electrode welding area (201) is W. 20 Where 4mm≤L 10 ≤6mm, 2mm≤W 10 ≤3mm, 3.5mm≤L 20 ≤5.5mm, 1.6mm≤W 20 ≤3.4mm.

5. A cylindrical secondary battery as described in claim 4, characterized in that: The positive electrode solder mark (102) is curved, and multiple positive electrode solder marks (102) located in the same positive electrode welding area (101) are arranged in parallel and at intervals; The distance between the opposite sides of two adjacent positive electrode solder marks (102) is W. 12 Of which, 12% W 10 ≤W 12 ≤22%W 10 .

6. A cylindrical secondary battery as described in claim 5, characterized in that: The span of the positive electrode solder mark (102) along the width direction of the positive electrode welding area (101) is W. 11 Of which, 17% W 10 ≤W 11 ≤27%W 10 .

7. A cylindrical secondary battery as described in claim 4, characterized in that: The negative electrode solder mark (202) is curved, and multiple negative electrode solder marks (202) located in the same negative electrode welding area (201) are arranged in parallel and at intervals; The spacing between two adjacent negative electrode solder marks (202) is W. 22 Where 0.6mm≤W 22 ≤1.1mm.

8. A cylindrical secondary battery as described in claim 7, characterized in that: The span of the negative electrode solder mark (202) along the width direction of the negative electrode welding area (201) is W. 21 The width of the negative electrode solder mark (202) is W. 23 Where, 0.15mm≤(W 21 -W 23 )≤0.35mm, 0.1mm≤W 23 ≤0.3mm, and W 23 <(W) 21 -W 23 ).

9. A cylindrical secondary battery as described in any one of claims 1-8, characterized in that: The positive electrode solder mark (102) includes a plurality of positive electrode straight solder lines (1021) and a plurality of positive electrode arc solder lines (1022), wherein the plurality of positive electrode straight solder lines (1021) and the plurality of positive electrode arc solder lines (1022) are arranged alternately and continuously, forming a wavy line shape, wherein the angle between one of the positive electrode straight solder lines (1021) and the two adjacent positive electrode straight solder lines (1021) is A and B respectively, wherein 50°≤A≤75°, 50°≤B≤75°; The negative electrode solder mark (202) includes multiple negative electrode straight solder lines (2021) and multiple negative electrode arc solder lines (2022), wherein the multiple negative electrode straight solder lines (2021) and multiple negative electrode arc solder lines (2022) are arranged alternately and continuously, forming a wavy line shape, wherein the angle between one of the negative electrode straight solder lines (2021) and the two adjacent negative electrode straight solder lines (2021) is C and D, respectively, wherein 70°≤C≤120° and 70°≤D≤120°.

10. A cylindrical secondary battery as described in any one of claims 1-8, characterized in that: The disk body (11) is provided with a central hole (103) and a peripheral hole (104), and the positive electrode welding area (101) is spaced apart from the central hole (103) and the peripheral hole (104); The negative electrode current collector (2) has a boss (21) in the middle. The boss (21) is used to weld and fix it to the battery casing. There are four negative electrode welding areas (201). The four negative electrode welding areas (201) are arranged in a circular array around the center point of the boss (21). The radius of the disk body (11) is R1, and the radius of the negative electrode current collector disk (2) is R2, wherein 8.5mm≤R1≤9.6mm and 8.5mm≤R2≤10.5mm.

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