A cylindrical lithium-ion battery

Abstract

The utility model relates to a cylindrical battery technical field, proposes a kind of cylindrical lithium ion battery, including shell, roll core, end plate and negative current collector plate;The one end of roll core is provided with negative electrode tab;The end plate is fixedly arranged on the shell;The negative current collector plate includes first bending part, second bending part and third bending part, and the first bending part is welded and fixed on the negative electrode tab;The diameter of shell is D 10 , the distance between the first bending part away from the second bending part one end and the shell inner wall is L 14 , L 14 / D 10 =2.3% to 4.5%.The utility model can improve the assembly quality and assembly efficiency of battery by setting S-shaped negative current collector plate, by limiting the spacing between the first bending part away from the second bending part one end and the shell inner wall, not only can be conveniently assembled to battery, avoid negative current collector plate and shell interference, but also can guarantee the overcurrent capacity between negative current collector plate and negative electrode tab, to effectively improve the overall performance of battery.

Description

Technical Field

[0001] This utility model relates to the field of cylindrical battery technology, and in particular to a cylindrical lithium-ion 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 lithium-ion batteries have gradually become one of the mainstream products in the market due to their excellent performance and high energy density.

[0003] The negative electrode current collector is a component inside the battery used to collect and conduct current. It can reduce the battery's internal resistance and improve the efficiency of electron movement, thereby enhancing the battery's power output and charge / discharge performance. For example, the utility model disclosed in CN214625311U discloses a multi-tab cylindrical battery with a current collector, which has a current collector between the cover plate and the tabs, and has a first bend and a second bend on the current collector. The bends in the current collector are used to connect the cover plate and the tabs and to allow the cover plate to be inserted into the casing.

[0004] The distance between the end of the negative current collector and the inner wall of the casing directly affects the overall performance of the battery. In the existing technology, this distance is not set reasonably. If the distance is too small, the negative current collector will easily interfere with the inner wall of the casing during battery assembly, affecting the assembly quality and effect. If the distance is too large, the weldable area between the negative current collector and the negative electrode tab will be reduced, the temperature rise at the welding position will be increased, and the battery performance will be affected. Utility Model Content

[0005] In view of this, the present invention proposes a cylindrical lithium-ion battery that can balance battery assembly efficiency and overcurrent capacity, 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 lithium-ion battery, including a shell, a core, an end plate, and a negative electrode current collector. One end of the shell has an opening; the core is disposed inside the shell, and one end of the core has a negative electrode tab; the end plate is fixedly disposed on the shell and seals the opening; the negative electrode current collector includes a first bent portion, a second bent portion, and a third bent portion, which are sequentially connected to form an S-shape. The first bent portion abuts against and is welded to the negative electrode tab, and the third bent portion is welded to the end plate; the diameter of the shell is D. 10 The distance between the end of the first bent portion away from the second bent portion and the inner wall of the outer casing is L. 14 L 14 / D 10 =2.3% - 4.5%.

[0007] Based on the above technical solutions, preferably, the distance between the end of the first bent portion near the second bent portion and the inner wall of the outer shell is L. 13 L 13 / D 10 =14% - 16.2%.

[0008] Based on the above technical solutions, preferably, the distance between the end of the third bending portion near the second bending portion and the inner wall of the outer shell is L. 12 L 12 / D 10 =23.8% - 28.2%.

[0009] More preferably, the distance between the end of the third bend away from the second bend and the inner wall of the outer casing is L. 11 L 11 / D 10 =6.5% - 10.5%.

[0010] Based on the above technical solutions, preferably, one side of the end plate is provided with a stamping groove, and the other side of the end plate is formed with a protrusion by stamping the stamping groove. The protrusion has an annular structure, and the end of the third bend near the second bend is located inside the protrusion; the radius of the outer shell is R. 10 The minimum distance between the end of the third bend near the second bend and the protrusion is L. 65 L 65 / R 10 =7.9% - 10.5%.

[0011] More preferably, the cross-section of the protrusion is an isosceles trapezoid, and the end of the third bend away from the second bend is welded and fixed to the side of the protrusion near the negative electrode tab; the circumference of the side of the protrusion near the negative electrode tab is W. 14 The minimum distance between the end of the third bend away from the second bend and the outer side of the protrusion is W. 15 W 15 / W 14 =8.3% - 14.4%.

[0012] More preferably, the minimum distance between the stamping groove and the center point of the end plate is W. 11 W 11 =12.15mm-14.15mm.

[0013] More preferably, the circumferential width of the stamping groove is W. 12 W 12 =5.6mm-7.6mm.

[0014] More preferably, the distance between the stamping groove and the periphery of the outer casing is W. 13 W 13 =2.25mm-4.25mm.

[0015] Based on the above technical solutions, the preferred option is D. 10 =44mm-48mm.

[0016] The cylindrical lithium-ion battery of this invention has the following advantages over the prior art:

[0017] (1) By setting an S-shaped negative current collector, the assembly quality and assembly efficiency of the battery can be improved. By limiting the distance between the end of the first bend away from the second bend and the inner wall of the outer casing, it is not only convenient to assemble the battery and avoid interference between the negative current collector and the outer casing, but also to ensure the overcurrent capacity between the negative current collector and the negative electrode tab, thereby effectively improving the overall performance of the battery.

[0018] (2) By further limiting the specifications and installation position of the negative current collector, the assembly efficiency and quality of the negative current collector can be further improved, and the safety performance of the battery can be further improved. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a partial cross-sectional view of a cylindrical lithium-ion battery according to the present invention.

[0021] Figure 2 This is a cross-sectional view of the outer casing and end plate of a cylindrical lithium-ion battery according to the present invention.

[0022] Figure 3 This is a cross-sectional view of the protruding part in a cylindrical lithium-ion battery according to the present invention.

[0023] Figure 4 This is a cross-sectional view of the third bend in a cylindrical lithium-ion battery of the present invention, near the end of the second bend.

[0024] Figure 5 This is a cross-sectional view of the end of the third bend away from the second bend in a cylindrical lithium-ion battery according to the present invention.

[0025] The components are: 1. Outer shell; 2. Negative electrode tab; 3. End plate; 31. Protrusion; 301. Stamping groove; 4. Negative electrode current collector; 41. First bend; 42. Second bend; 43. Third bend. Detailed Implementation

[0026] 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.

[0027] The present invention relates to a cylindrical lithium-ion battery, comprising a casing 1, a core, an end plate 3, and a negative electrode current collector 4.

[0028] The outer shell 1 is a cylindrical structure. Both the positive and negative ends of the outer shell 1 are provided with openings. The core is placed inside the outer shell 1. The two ends of the core are respectively provided with positive electrode tabs and negative electrode tabs 2. The negative electrode current collector 4 is welded and fixed between the negative electrode tab 2 and the end plate 3. The end plate 3 is fixedly placed on the negative end of the outer shell 1, and the end plate 3 blocks the opening of the negative end of the outer shell 1, thereby achieving the sealing of the negative end of the outer shell 1 and the conduction between the negative electrode tab 2 and the end plate 3.

[0029] The negative electrode current collector 4 has a long strip structure. First, one end of the negative electrode current collector 4 is welded and fixed to the negative electrode tab 2. Then, the other end of the negative electrode current collector 4 is welded and fixed to the end plate 3. Finally, by bending the negative electrode current collector 4, the negative electrode current collector 4 is formed into an S-shape, so that the end plate 3 can be fixedly installed on the negative terminal of the outer casing 1 to realize the assembly of the battery.

[0030] When assembling the battery using the above process, the welding convenience between the negative electrode current collector 4 and related components can be improved, thereby effectively improving the assembly quality and efficiency of the battery.

[0031] like Figures 1-3 As shown, the end plate 3 has a protrusion 31 on the side near the negative electrode tab 2. The protrusion 31 has an annular structure. The end of the negative electrode current collector 4 away from the negative electrode tab 2 is welded and fixed to the side of the protrusion 31 near the negative electrode tab 2.

[0032] The end plate 3 is a circular plate structure. A stamping groove 301 is provided on the side of the end plate 3 away from the protrusion 31. By stamping the stamping groove 301, the protrusion 31 can be formed on the other side of the end plate 3. The stamping groove 301 is also an annular structure.

[0033] like Figure 3As shown, in order to facilitate the stamping of the stamping groove 301 and improve the processing quality and efficiency of the protrusion 31, it is preferable to set the cross-section of the stamping groove 301 to be an isosceles trapezoid.

[0034] The negative electrode current collector 4 includes a first bending portion 41, a second bending portion 42 and a third bending portion 43, which are connected in sequence to form an S-shape, and the first bending portion 41, the second bending portion 42 and the third bending portion 43 are parallel to each other.

[0035] The entire first bent portion 41 is attached to the negative electrode tab 2, and the entire first bent portion 41 is welded and fixed to the negative electrode tab 2. The end of the third bent portion 43 away from the second bent portion 42 is welded and fixed to the bottom side of the protrusion 31, and the end of the third bent portion 43 close to the second bent portion 42 is located inside the protrusion 31.

[0036] like Figure 1 As shown, the diameter of the outer shell 1 is D. 10 The distance between the end of the first bend 41 away from the second bend 42 and the inner wall of the outer casing 1 is L. 14 The distance between the end of the first bend 41 near the second bend 42 and the inner wall of the outer casing 1 is L. 13 The distance between the end of the third bend 43 closest to the second bend 42 and the inner wall of the outer casing 1 is L. 12 The distance between the end of the third bend 43 away from the second bend 42 and the inner wall of the outer casing 1 is L. 11 .

[0037] In some embodiments, D 10 =44mm-48mm, that is, the diameter of the outer shell 1 is 44mm, 46mm or 48mm, etc.

[0038] In some embodiments, L 14 / D 10 =2.3%-4.5%, meaning the distance between the end of the first bend 41 away from the second bend 42 and the inner wall of the outer casing 1 is 2.3%, 3.4%, or 4.5% of the diameter of the outer casing 1, etc. If L 14 / D 10 If L < 2.3%, the distance between the end of the first bend 41 away from the second bend 42 and the inner wall of the outer casing 1 is too small. During battery assembly, the first bend 41 will interfere with the inner wall of the outer casing 1, affecting the assembly quality and efficiency of the battery. 14 / D 10 If the temperature rises to >4.5%, the distance between the end of the first bend 41 away from the second bend 42 and the inner wall of the outer casing 1 is too large. This means that the welding area between the first bend 41 and the negative electrode tab 2 is reduced, and the temperature rise at the welding position is increased, which will affect the performance of the battery.

[0039] In some embodiments, L 13 / D 10 =14%-16.2%, meaning the distance between the end of the first bend 41 near the second bend 42 and the inner wall of the outer casing 1 is 14%, 15.1%, or 16.2% of the diameter of the outer casing 1, etc. If L 13 / D 10 If the value is less than 14%, the distance between the end of the first bend 41 near the second bend 42 and the inner wall of the outer casing 1 is too small. When the negative current collector 4 is bent into the casing, it is easy for the negative current collector 4 to interfere with the inner wall of the outer casing 1, affecting battery assembly. If L 13 / D 10 If the value is greater than 16.2%, the distance between the end of the first bend 41 near the second bend 42 and the inner wall of the outer casing 1 is too large. This reduces the welding area between the first bend 41 and the negative electrode tab 2, resulting in a weakening of the current-carrying capacity at the welding position, an increase in temperature, and an impact on the battery's performance.

[0040] In some embodiments, L 12 / D 10 =23.8%-28.2%, meaning the distance between the end of the third bend 43 closest to the second bend 42 and the inner wall of the outer casing 1 is 23.8%, 26%, or 28.2% of the diameter of the outer casing 1, etc. If L 12 / D 10 If the distance between the end of the third bend 43 closest to the second bend 42 and the inner wall of the outer casing 1 is too small, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery; if L 12 / D 10 If the distance between the end of the third bend 43 and the inner wall of the outer casing 1 is too large, the overall length of the negative electrode current collector 4 will be shortened. This will cause the end plate 3 to be too close to the end of the outer casing 1 when it is welded to the negative electrode current collector 4, affecting the welding quality between the end plate 3 and the negative electrode current collector 4 and reducing the production quality and efficiency of the battery.

[0041] In some embodiments, L 11 / D 10 =6.5%-10.5%, meaning the distance between the end of the third bend 43 away from the second bend 42 and the inner wall of the outer casing 1 is 6.5%, 8.5%, or 10.5% of the diameter of the outer casing 1, etc. If L 11 / D 10 If the distance between the third bend 43 and the inner wall of the outer casing 1 is less than 6.5%, the distance between the end of the third bend 43 away from the second bend 42 and the inner wall of the outer casing 1 will be too small. During battery assembly, the third bend 43 will interfere with the inner wall of the outer casing 1, affecting the assembly quality and efficiency. 11 / D 10If the value is greater than 10.5%, the distance between the end of the third bend 43 away from the second bend 42 and the inner wall of the outer casing 1 is too large. This means that the welding area between the third bend 43 and the end plate 3 is reduced, and the temperature rise at the welding position is increased, which will affect the performance of the battery.

[0042] like Figures 2-5 As shown, the radius of the outer shell 1 is R. 10 The minimum distance between the end of the third bend 43 closest to the second bend 42 and the protrusion 31 is L. 65 The ring width of the protruding part 31 near the negative electrode tab 2 is W. 14 The minimum distance between the end of the third bend 43 furthest from the second bend 42 and the outer side of the protrusion 31 is W. 15 The minimum distance between the stamping groove 301 and the center point of the end plate 3 is W. 11 The circumferential width of the stamping groove 301 is W. 12 The distance between the stamping groove 301 and the periphery of the outer shell 1 is W. 13 .

[0043] In some embodiments, L 65 / R 10 =7.9%-10.5%, meaning the minimum distance between the end of the third bend 43 near the second bend 42 and the protrusion 31 is 7.9%, 9.2%, or 10.5% of the radius of the outer shell 1, etc. If L 65 / R 10 If the distance between the third bend 43 and the protrusion 31 is less than 7.9%, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery; if L 65 / R 10 If the distance between the third bend 43 and the protrusion 31 is too large, the overall length of the negative electrode current collector 4 will be shortened. This will cause the end plate 3 to be too close to the end of the outer shell 1 when it is welded to the negative electrode current collector 4, affecting the welding quality of the end plate 3 and the negative electrode current collector 4, and reducing the production quality and efficiency of the battery.

[0044] In some embodiments, W 15 / W 14 =8.3%-14.4%, meaning the minimum distance between the end of the third bend 43 furthest from the second bend 42 and the outer side of the protrusion 31 is 8.3%, 11.4%, or 14.4% of the ring width of the protrusion 31 on the side closer to the negative electrode tab 2, etc. If W 15 / W 14If W < 8.3%, the distance between the end of the third bend 43 furthest from the second bend 42 and the outer side of the protrusion 31 is too small. On the one hand, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery. On the other hand, the edges of the third bend 43 and the protrusion 31 are too close, which will affect the welding quality of the two. 15 / W 14 If the temperature rises to >14.4%, the distance between the end of the third bend 43 away from the second bend 42 and the outer side of the protrusion 31 is too large. This means that the welding area between the third bend 43 and the end plate 3 is reduced, and the temperature rise at the welding position is increased, which will affect the performance of the battery.

[0045] In some embodiments, W 11 =12.15mm-14.15mm, meaning the minimum distance between the center point of the stamping groove 301 and the end plate 3 is 12.15mm, 13.15mm, or 14.15mm, etc. If W 11 If the distance between the stamping groove 301 and the center point of the end plate 3 is less than 12.15mm, the stamping groove 301 will move towards the center of the end plate 3. Since the groove of the explosion-proof valve is usually set on the end plate 3 inside the stamping groove 301, when the stamping groove 301 moves inward, it will affect the opening area of ​​the groove of the explosion-proof valve and affect the safety performance of the battery; if W 11 If the distance is greater than 14.15mm, the distance between the stamping groove 301 and the center point of the end plate 3 is too large. When the position of the third bending part 43 remains unchanged, the welding area between the third bending part 43 and the protrusion 31 is reduced, which leads to a decrease in the current carrying capacity of the welding position and an increase in the temperature rise of the welding position, affecting the performance of the battery.

[0046] In some embodiments, W 12 =5.6mm-7.6mm, meaning the circumferential width of the stamping groove 301 is 5.6mm, 6.6mm, or 7.6mm, etc. If W 12 If the diameter is less than 5.6mm, the circumferential width of the stamping groove 301 is too small, the area of ​​the protrusion 31 becomes smaller, the welding area between the negative electrode current collector 4 and the end plate 3 decreases, resulting in reduced current carrying capacity at the welding position, increased temperature rise at the welding position, and impact on battery performance; if W 12 If the circumference of the stamping groove 301 is greater than 7.6mm, the stamping groove 301 will move towards the center of the end plate 3. Since the groove of the explosion-proof valve is usually set on the end plate 3 inside the stamping groove 301, when the stamping groove 301 moves inward, it will affect the opening area of ​​the groove of the explosion-proof valve and affect the safety performance of the battery.

[0047] In some embodiments, W 13 =2.25mm-4.25mm, meaning the distance between the stamping groove 301 and the perimeter of the outer casing 1 is 2.25mm, 3.25mm, or 4.25mm, etc. If W 13If the distance is less than 2.25mm, the gap between the stamping groove 301 and the periphery of the outer casing 1 is too small, and the protrusion 31 is too close to the edge of the end plate 3. When the end plate 3 is installed on the outer casing 1, the protrusion 31 is prone to interference with the inner wall of the outer casing 1, affecting the assembly quality and assembly efficiency of the battery; if W 13 If the distance is greater than 4.25mm, the gap between the stamping groove 301 and the periphery of the outer casing 1 is too large. The protrusion 31 moves inward toward the center of the end plate 3. When the position of the third bending part 43 remains unchanged, the welding area between the third bending part 43 and the protrusion 31 is reduced, resulting in a decrease in the current carrying capacity of the third bending part 43 and the protrusion 31, an increase in the temperature rise at the welding position, and an impact on the battery performance.

[0048] 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 by: The application relates to a negative electrode plate, which comprises a shell (1), a winding core, an end plate (3) and a negative electrode current collector (4), wherein, one end of the shell (1) is provided with an opening; the winding core is arranged in the shell (1), and one end of the winding core is provided with a negative electrode tab (2); the end plate (3) is fixedly arranged on the shell (1) and blocks the opening; the negative electrode current collector (4) comprises a first bending part (41), a second bending part (42) and a third bending part (43), the first bending part (41), the second bending part (42) and the third bending part (43) are sequentially connected and form an S shape, the first bending part (41) is close to and fixedly welded on the negative electrode tab (2), and the third bending part (43) is fixedly welded on the end plate (3); The diameter of the shell (1) is D 10 The distance between the first bending part (41) and the inner wall of the shell (1) is L 14 , L 14 / D 10 =2.3%-4.5%.

2. A cylindrical lithium-ion battery according to claim 1, characterized in that: The first bending part (41) is adjacent to one end of the second bending part (42) and the distance from the inner wall of the shell (1) is L 13 , L 13 / D 10 = 14%-16.2%.

3. A cylindrical lithium-ion battery according to claim 1, wherein: The third bending part (43) is close to one end of the second bending part (42) and the distance from the inner wall of the shell (1) is L 12 , L 12 / D 10 = 23.8% - 28.2%.

4. A cylindrical lithium-ion battery according to claim 3, wherein: The third bending part (43) is away from the second bending part (42) one end and the distance of the inner wall of the shell (1) is L 11 , L 11 / D 10 = 6.5%-10.5%.

5. A cylindrical lithium-ion battery according to claim 1, wherein: one side of the end plate (3) is provided with a punching groove (301), the other side of the end plate (3) is provided with a protruding part (31) formed by punching the punching groove (301), the protruding part (31) is in an annular structure, and one end of the third bending part (43) close to the second bending part (42) is located in the interior of the protruding part (31); The radius of the shell (1) is R 10 The minimum distance between the third bending part (43) and the convex part (31) near one end of the second bending part (42) is L 65 L 65 / R 10 = 7.9% - 10.5%.

6. A cylindrical lithium-ion battery according to claim 5, wherein: the cross section of the protruding part (31) is isosceles trapezoidal, and one end of the third bending part (43) away from the second bending part (42) is fixedly welded on one side of the protruding part (31) close to the negative electrode tab (2); the cross section of the protruding part (31) is isosceles trapezoidal, and one end of the third bending part (43) away from the second bending part (42) is fixedly welded on one side of the protruding part (31) close to the negative electrode tab (2). The ring width of the protruding part (31) near the negative tab (2) side is W 14 The minimum distance of the third bending part (43) far from the second bending part (42) end and the outside of the protruding part (31) is W 15 , W 15 / W 14 = 8.3% - 14.4%.

7. A cylindrical lithium-ion battery according to claim 5, wherein: The minimum distance of the punching groove (301) from the center point of the end plate (3) is W 11 , W 11 = 12.15 mm - 14.15 mm.

8. A cylindrical lithium-ion battery according to claim 7, characterized in that: The ring width of the punching groove (301) is W 12 , W 12 = 5.6mm-7.6mm.

9. A cylindrical lithium-ion battery according to claim 8, wherein: The punch groove (301) has a distance W from the outer shell (1) periphery 13 , W 13 = 2.25mm - 4.25mm.

10. A cylindrical lithium-ion battery according to any of claims 1-9, characterized in that: D 10 = 44 mm - 48 mm.

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