A cylindrical lithium-ion battery

Abstract

The utility model provides a kind of cylindrical lithium ion battery, belong to lithium battery field, current collector disc includes disc body and tail body;The pole lug of roll core is welded on disc body;End plate is welded with tail body;The area of circle drawn with the radius of disc body is the space area of disc body, disc body is provided with several rectangular first welding area, and the sum of the area of several first welding area is 12~24% of disc body space area;The area of circle drawn with the radius of end plate and remove the area of several surrounding holes and boss is the actual area of end plate;Second welding area of rectangular is provided on tail body, and the area of second welding area is 4.5~8.5% of end plate actual area.The utility model discloses the area size of welding area on disc body and tail body of positive electrode current collector disc is reasonably set simultaneously, can make welding area have larger welding area, thus guarantee that the structure of welding mark has good current overcurrent capacity, and also can take into account relatively smaller wire resistance.

Description

Technical Field

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

[0002] Cylindrical lithium-ion batteries are among the most widely sold battery types on the market. The top cap structure of a cylindrical battery typically consists of a top cover, an explosion-proof sheet, and a bottom plate, arranged from top to bottom. The top end of the cylindrical core is flattened to form the positive electrode tab. After the positive electrode tab is welded to the current collector, it is then welded to the bottom plate via the square tail of the current collector, thus assembling the cylindrical battery. Existing cylindrical batteries suffer from inadequate design, both in the welding area between the positive current collector and the core tab, and in the welding area on the tail of the positive current collector. This weakens the current carrying capacity of the welding area and increases the welding defect rate, ultimately affecting the overall battery performance. Utility Model Content

[0003] In view of this, the present invention proposes a cylindrical lithium-ion battery.

[0004] The technical solution of this utility model is implemented as follows: This utility model provides a cylindrical lithium-ion battery, including a current collector, a disk body, and a tail body connected to the disk body; a core having tabs welded to the disk body; and an end plate disposed above the current collector and welded to the tail body; wherein, the area of ​​a circle drawn with radius R1 of the disk body is the spatial area S1 of the disk body, and the disk body is provided with a plurality of rectangular strip-shaped first welding areas, the area of ​​the plurality of first welding areas being S1. 11 The sum of the areas is 12-24% of the disk space area S1; the end plate has a protruding boss at its center, far from the collector disk, and several surrounding holes are formed around the boss. The actual area S3 of the end plate is obtained by drawing a circle with radius R3 of the end plate and subtracting the area of ​​the boss and surrounding holes; a rectangular strip-shaped second welding area is provided on the tail body, and the area of ​​the second welding area is S. 21 It is 4.5% to 8.5% of the actual area S3 of the end plate.

[0005] Based on the above technical solutions, the preferred area S of each first welding zone is... 11 It is 4 to 5% of the disk space area S1.

[0006] Based on the above technical solutions, preferably, a number of first welding zones are arranged around the center of the disk body, with the two ends of the length direction of each first welding zone extending toward the middle and edge of the disk body respectively; the length direction of the second welding zone is the width direction of the tail body.

[0007] More preferably, the length L of the first welding zone 11 The width W of the first welding zone is 48-62% of the disk radius R1. 11It is 20-30% of the disk radius R1; the length L of the second welding area 21 The width of the tail section is 56-76% of the width L2, and the width of the second welding zone is W. 21 It is 15-32% of the end plate radius R3.

[0008] Based on the above technical solution, preferably, a plurality of first welding lines are arranged in parallel within the first welding zone, with adjacent first welding lines spaced apart, and the minimum spacing W between adjacent first welding lines. 110 The width W of the first welding area 11 12-22%.

[0009] More preferably, the width W of the first bonding wire 111 The width W of the first welding area 11 17-27%.

[0010] More preferably, the first weld line is a wavy line and is formed by connecting several first wave units end to end, and the included angle α of the tangents at both ends of each first wave unit is 50 to 75°.

[0011] Based on the above technical solutions, preferably, a second welding line is provided in the second welding zone. The second welding line is a wavy line and is formed by connecting several second wave units end to end. The included angle β of the tangents at both ends of each second wave unit is 25 to 65°.

[0012] Based on the above technical solutions, preferably, the center of the disk body has a central hole and a number of air holes are formed around the central hole; the first welding area is set between adjacent air holes.

[0013] Based on the above technical solutions, preferably, the end plate has a boss protruding away from the collector plate at its center and several surrounding holes are provided around the boss; the second welding area is located between the boss and the surrounding holes.

[0014] The cylindrical lithium-ion battery of this invention has the following advantages over the prior art:

[0015] (1) By simultaneously and reasonably setting the welding area size on the positive current collector plate and the tail plate, this utility model can make the welding area have a large welding area, thus ensuring that the welding stamp structure has good current carrying capacity, while also taking into account a relatively small internal resistance of the welding wire, and having a reasonable welding time and welding efficiency, avoiding increasing the welding defect rate, thereby effectively improving the overall performance of the battery.

[0016] (2) The present invention designs the length, width, spacing and relative position of the welding wire relative to the end plate or current collector to avoid the welding wire being too close to the end of the positive current collector tail body or extending beyond the surface of the end plate, which would reduce the effective welding area and weaken the current carrying capacity of the welding wire. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a bottom view of the collector plate of this utility model;

[0019] Figure 2 This is a bottom view of the end plate of this utility model;

[0020] Figure 3 This is a schematic diagram of the welding area of ​​this utility model;

[0021] Figure 4 This is a schematic diagram of the bonding wire of this utility model.

[0022] In the diagram: 1. Disc body; 11. First welding area; 111. First welding line; 112. First wave unit; 2. Tail body; 21. Second welding area; 211. Second welding line; 212. Second wave unit; 3. End plate. Detailed Implementation

[0023] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. 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 of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0024] like Figure 1 As shown, combined with Figure 2 The present invention relates to a cylindrical lithium-ion battery, comprising a current collector, a winding core, and an end plate 3.

[0025] The current collector includes a plate body 1 and a tail body 2. Here, the current collector refers to the upright current collector, which is located between the lower end plate of the top cover assembly and the battery core. The current collector inside the cylindrical battery is nearly circular, while the tail body 2 is a rectangular sheet connected to the edge of the plate body 1. Before being welded to the end plate 3, it is bent upwards.

[0026] After the core is flattened, it has a tab on its top, which is then welded to the disc body 1.

[0027] End plate 3 refers to the lower end plate of the top cover assembly, which is located above the collector plate and welded to the tail body 2.

[0028] The area of ​​the circle drawn with radius R1 of disk 1 is the spatial area S1 of disk 1. The preferred range for the spatial area S1 of disk 1 is generally 240-280 mm. 2 The disk body 1 has several rectangular strip-shaped first welding areas 11, the area S of which is... 11 The preferred range is generally 10–13 mm. 2 Several first welding zones, each with an area S 11 The sum of the areas is 12-24% of the space area S1 of the disk body 1; the end plate 3 has a protruding boss at its center that protrudes away from the collector disk and has several surrounding holes around the boss. The actual area S3 of the end plate 3 is the area drawn with the radius R3 of the end plate 3 and the area of ​​the boss and surrounding holes is the area of ​​the end plate 3; the tail body 2 has a rectangular strip-shaped second welding area 21, and the area of ​​the second welding area 21 is S. 21 The range is generally 4–7.5 mm. 2 5-7mm is preferred 2 The area S of the second welding zone 21 21 The area of ​​the end plate 3 is 4.5% to 8.5% of the actual area S3. If the welding area is too small, the corresponding solder joint area will be reduced, causing the battery's internal resistance to increase. The reduced effective area of ​​the solder wire will weaken the current carrying capacity of the solder wire, leading to an increase in temperature at the solder joint and consequently, the battery's temperature, thus affecting battery performance. Conversely, if the welding area is too large, the excessively large welding area will lengthen the solder wire, not only failing to improve the battery's internal resistance but also increasing the welding time, reducing welding efficiency, and increasing the risk of solder wire defects, leading to a higher defect rate, increased battery manufacturing costs, and decreased efficiency. This solution, by simultaneously and reasonably setting the welding area size on both the positive current collector plate 1 and the tail plate 2, achieves a larger welding area, ensuring good current carrying capacity of the solder joint structure while maintaining relatively low solder wire internal resistance, reasonable welding time and efficiency, and avoiding increased solder defect rate, thereby effectively improving the overall battery performance. For example, in this embodiment, the radius R1 of the disk body 1 is 9.1 mm, therefore the spatial area S1 of the disk body 1 is 260 mm². 2 The length and width of the first welding area 11 are L and L respectively. 11 =5mm, W 11 = 2.3mm, therefore the area S of the first welding zone 11 11 =11.5mm 2 Four first welding areas 11 are arranged around the perimeter, and the sum of the areas of the four first welding areas 11 is 46 mm. 2Therefore, the area S of several first welding zones 11 11 The sum of their areas is 18% of the spatial area S1 of disk 1. The actual area S3 of end plate 3 is 89.25 mm. 2 The length and width of the second welding area 21 are L and L respectively. 21 =4mm, W 21 =1.5mm, therefore the area S of the first welding zone 11 11 =6mm 2 The area of ​​the second welding zone 21 is S 21 It is 6.7% of the actual area S3 of end plate 3.

[0029] exist Figure 1 In a preferred embodiment shown, the area S of each first welding zone 11 11 The area S1 of the disk body 1 is 3-6%, preferably 4-5%; the area S of several first welding areas 11 is... 11 The sum of the areas is preferably 16% to 20% of the total area of ​​the disk body 1 relative to the spatial area S1. For example, in this embodiment, the spatial area S1 of the disk body 1 is 260 mm². 2 The length and width of the first welding area 11 are L and L respectively. 11 =5mm, W 11 = 2.3mm, therefore the area S of the first welding zone 11 11 =11.5mm 2 Four first welding areas 11 are arranged around the perimeter, and the sum of the areas of the four first welding areas 11 is 46 mm. 2 The area S of a single first welding zone 11 11 It is 4.5% of the space area S1 of disk body 1, and the area S of the four first welding areas 11 is... 11 The sum of the areas is 18% of the space area S1 of disk 1, which is within a reasonable range.

[0030] exist Figure 1 In a preferred embodiment shown, a plurality of first welding areas 11 are arranged around the center of the disk body 1, with both ends of the length direction of each first welding area 11 extending toward the middle and edge of the disk body 1, respectively; the length direction of the second welding area 21 is the width direction of the tail body 2. Ideally, the length direction of the first welding area 11 extends radially along the disk body 1, but in the actual manufacturing process, the first welding area 11 may also be offset relative to the radial direction of the disk body 1. Generally speaking, the arrangement position and extension direction of the plurality of first welding areas 11 are radially symmetrical with respect to the central axis of the entire collector disk.

[0031] exist Figure 3 In a preferred embodiment shown, the radius R1 of the disk body 1 is preferably in the range of 8.5 to 9.6 mm, and the length L of the first welding area 11 is... 11The preferred range is 4–6 mm, and the width W of the first welding area 11 is... 11 The preferred range is 2-3 mm, and the length L of the first welding area 11 is... 11 The width W of the first welding area 11 is 48-62% of the radius R1 of the disk body 1. 11 The radius R1 of the disc body 1 is 20-30%; the radius R3 of the end plate 3 is preferably in the range of 5.29-7.29 mm; the width W2 of the tail body 2 is preferably in the range of 5-7 mm; and the length L of the second welding area 21 is... 21 The preferred range is 3.5–4.5 mm, and the width W of the second welding area 21 is... 21 The preferred range is 1-2 mm, and the length L of the second welding area 21 is... 21 The width of the tail section 2 is 56-76% of the width L2, and the width of the second welding area 21 is W. 21 The length and width of the solder joint are 15-32% of the radius R3 of the end plate 3. If the length or width of the solder joint is too small, the effective welding area will decrease, the current carrying capacity of the solder wire will weaken, and the temperature at the solder wire will rise, affecting battery performance. Conversely, if the length or width of the solder joint is too large, it will not significantly improve the battery's internal resistance, but the increased width will increase the welding time, leading to decreased welding efficiency and increased risk of welding defects, resulting in a higher defect rate. For example, in this embodiment, the radius R1 of the disk 1 is 9.1 mm, and the length L of the first welding area 11 is... 11 =5mm, the width W of the first welding area 11 11 = 2.3mm, the length L of the first welding area 11 11 The width W of the first welding area 11 is 55% of the radius R1 of the disk body 1. 11 The radius of the disc body 1 is 25% of the radius R1; the radius of the end plate 3 is R3 = 6.29 mm; the width of the tail body 2 is W2 = 6 mm; and the length of the second welding area 21 is L. 21 =4mm, the width W of the second welding area 21 21 =1.5mm, the length L of the second welding zone 21 21 The width of the tail section 2 is 67% of the width L2, and the width of the second welding area 21 is W. 21 It is 24% of the radius R3 of end plate 3.

[0032] exist Figure 3 In a preferred embodiment shown, a plurality of first welding lines 111 are arranged in parallel within the first welding area 11, with adjacent first welding lines 111 spaced apart. The width W of the first welding area 11 is... 11 The preferred range is 2-3 mm, and the minimum spacing W between adjacent first bonding lines 111 is... 110 The preferred range is 0.3–0.5 mm, and the minimum spacing W between adjacent first weld lines 111 is... 110 Width W of the first welding zone 11 11The spacing between adjacent first weld lines 111 is 12-22%. If the spacing is too large, the process cannot meet the requirements, and the weld lines are prone to deviating from the first welding area 11 on the disk body 1, increasing ineffective conductive paths and leading to a longer current path, as well as higher internal resistance and uneven current flow. Furthermore, it can easily cause insufficient weld connection strength. Conversely, if the spacing is too small, it can cause localized over-melting due to concentrated welding energy, leading to weld bursts and other problems. It may also cause concentrated heat generation during current collector welding, resulting in excessive rate rise, and may still lead to insufficient weld connection strength. For example, in this embodiment, the width W of the first welding area 11 is... 11 =2.3mm, minimum spacing W between adjacent first solder lines 111 110 =0.4mm, minimum spacing W between adjacent first weld lines 111 110 Width W of the first welding zone 11 11 17%.

[0033] exist Figure 3 In a preferred embodiment shown, the width W of the first bonding wire 111 111 The preferred range is 0.4–0.6 mm, and the width W of the first bonding line 111 is... 111 Width W of the first welding zone 11 11 The width of the solder wire is 17% to 27%. If the solder wire width is too large, it will easily deviate from the first soldering area 11 on the disk 1, resulting in a longer current guiding path, leading to higher internal resistance and uneven current distribution in the battery, and also easily causing insufficient soldering connection strength. If the solder wire width is too small, it will easily lead to problems such as soldering bursts, and may also cause concentrated heat generation during current collector soldering, resulting in excessive rate temperature rise. In addition, it may still cause insufficient soldering connection strength. For example, in this embodiment, the width W of the first soldering area 11 is... 11 = 2.3mm, the width W of the first solder line 111 111 =0.5mm, minimum spacing W between adjacent first solder lines 111 110 Width W of the first welding zone 11 11 22%.

[0034] exist Figure 4In a preferred embodiment shown, the first weld line 111 is a wavy line formed by connecting several first wave units 112 end to end. It can also be a continuous weld line in a Z-shape, or the weld line can extend in a serpentine manner. The included angle α of the tangents at both ends of each first wave unit 112 is 50° to 75°. For example, in this embodiment, the included angle α of each first wave unit 112 is 60°; however, in actual implementation, the several first wave units 112 are divided into two groups along the centerline of the first weld line 111, and the two groups of first wave units 112 are alternately arranged. Therefore, the included angle α of the two groups of first wave units 112 can be different. If the included angle of the weld line is too small, the continuous weld lines will be completely concentrated together, resulting in the complete concentration of energy and heat in the weld line. This can cause the weld line to easily develop punctures, change the color of the weld line, and thus increase the welding defect rate. If the included angle of the welding wire is too large, the total length of the welding wire needs to be increased. Due to the process deviation of the welding wire itself, after the straight distance between the beginning and end of the welding wire in the lateral direction is increased, it is easy to approach the outer contour of the current collector plate 1. This will make it easy for the welding wire to be welded out of the outer side of the current collector plate 1, resulting in a reduction in the effective welding area of ​​the soldering structure in the first welding area 11, a weakening of the current carrying capacity of the welding part, an increase in temperature at the welding wire, and thus affecting the performance of the battery.

[0035] exist Figure 4 In a preferred embodiment shown, a second welding line 211 is provided in the second welding area 21, and the line width D of the second welding line 211 is... 21 The range is 0.2–0.4 mm. The second weld line 211 is a wavy line formed by connecting several second wave units 212 end to end. It can also be a continuous weld line in a Z-shape, or the weld line extends in a serpentine manner. The included angle β of the tangents at both ends of each second wave unit 212 is 25–65°. Similarly, for example, in this embodiment, the line width D of the second weld line 211 is... 21 =0.3mm, and the included angle β of each second wave unit 212 is 41°; however, in actual implementation, several second wave units 212 are divided into two groups along the center line of the second welding line 211, and the two groups of second wave units 212 are alternately arranged, so the included angle β of the two groups of second wave units 212 may be different.

[0036] exist Figure 1 In a preferred embodiment shown, a central hole is provided in the center of the disk body 1, which corresponds to the channel in the middle of the core; a plurality of air holes are provided around the central hole, which are mainly used to discharge the gas generated by the cell reaction. A first welding area 11 is provided between adjacent air holes, and a plurality of first welding areas 11 are arranged around the central hole.

[0037] exist Figure 2In a preferred embodiment shown, the end plate 3 has a protruding boss at its center, away from the current collector, and several surrounding holes are formed around the boss. The boss can also be a boss hole, forming a groove or hole, mainly used to accommodate the welding wire. Specifically, when the boss of the end plate 3 and the explosion-proof sheet inside the cap are welded to achieve electrical connection, the welding wire is accommodated in the boss. The surrounding holes are mainly used to discharge the gas generated by the cell reaction. The second welding area 21 is located in the solid part between the boss and the surrounding holes. Theoretically, the edge of the end of the tail body 2 that bends towards the middle of the current collector 1 presses on the center of the end plate 3, so that the end of the tail body 2 passes through the center of the end plate 3. However, in the actual process, there are deviations in the placement of the cap and the position of the folded tab. The accumulation of these deviations may cause the end of the tail body 2 to actually not pass through the center, possibly shifting upwards or downwards.

[0038] 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 lithium-ion battery, characterized in that, include: The collector includes a disk body (1) and a tail body (2) connected to the disk body (1); The core has tabs that are welded to the disc body (1); End plate (3) is disposed above the collector plate and welded to the tail body (2); Wherein, the area of ​​the circle drawn with radius R1 of the disk body (1) is the spatial area S1 of the disk body (1), and the disk body (1) is provided with a plurality of rectangular strip-shaped first welding areas (11), the area of ​​the plurality of first welding areas (11) is S 11 The sum of their areas is 12-24% of the area S1 of the disk body (1); The end plate (3) has a boss protruding away from the collector plate at its center and several surrounding holes are provided around the boss. The actual area S3 of the end plate (3) is obtained by drawing a circle with the radius R3 of the end plate (3) and removing the area of ​​the boss and surrounding holes. The tail body (2) is provided with a rectangular strip-shaped second welding area (21), the area of ​​the second welding area (21) is S. 21 The actual area S3 of the end plate (3) is 4.5 to 8.5%.

2. A cylindrical lithium-ion battery according to claim 1, characterized in that: The area S of each of the first welding areas (11) 11 It is 4 to 5% of the spatial area S1 of the disk body (1).

3. A cylindrical lithium-ion battery according to claim 1, characterized in that: Several first welding areas (11) are arranged around the center of the disk body (1), and the two ends of each first welding area (11) extend toward the middle of the disk body (1) and the edge of the disk body (1) respectively in the length direction; The length direction of the second welding area (21) is the width direction of the tail body (2).

4. A cylindrical lithium-ion battery according to claim 3, characterized in that: The length L of the first welding area (11) 11 The width W of the first welding area (11) is 48-62% of the radius R1 of the disk body (1). 11 It is 20-30% of the radius R1 of the disk body (1); The length L of the second welding area (21) 21 The width of the tail body (2) is 56-76% of the width L2, and the width of the second welding area (21) is W. 21 It is 15-32% of the radius R3 of the end plate (3).

5. A cylindrical lithium-ion battery according to claim 1, characterized in that: A plurality of first welding lines (111) are arranged in parallel within the first welding area (11), with adjacent first welding lines (111) spaced apart, and the minimum spacing W between adjacent first welding lines (111) is... 110 The width W of the first welding area (11) 11 12-22%.

6. A cylindrical lithium-ion battery according to claim 5, characterized in that: The width W of the first bonding wire (111) 111 The width W of the first welding area (11) 11 17-27%.

7. A cylindrical lithium-ion battery according to claim 5, characterized in that: The first weld line (111) is a wavy line and is formed by connecting several first wave units (112) end to end. The included angle α of the tangents at both ends of each first wave unit (112) is 50 to 75°.

8. A cylindrical lithium-ion battery according to claim 1, characterized in that: The second welding area (21) is provided with a second welding line (211). The second welding line (211) is a wavy line and is formed by connecting several second wave units (212) end to end. The included angle β of the tangents at both ends of each second wave unit (212) is 25 to 65°.

9. A cylindrical lithium-ion battery according to claim 1, characterized in that: The disk body (1) has a central hole and several air holes around the central hole; the first welding area (11) is located between adjacent air holes.

10. A cylindrical lithium-ion battery according to claim 1, characterized in that: The end plate (3) has a boss protruding away from the collector plate at its center and several surrounding holes are provided around the boss; the second welding area (21) is located between the boss and the surrounding holes.

Images