Positive collector plate encapsulation structure and cylindrical secondary battery

Abstract

The utility model relates to the technical field of cylindrical secondary batteries, and provides a positive pole current collecting plate rubber coating structure and a cylindrical secondary battery, the positive pole current collecting plate rubber coating structure comprises a rubber coating and a positive pole current collecting plate, the rubber coating is used for sleeving the outer side of a roll core, one end of the rubber coating is integrally formed with a flanging part, and the flanging part is of an annular structure; the positive collector plate is fixed between the roll core and the flanging part in an abutting manner; the radius of the positive collector plate is R0, the ring width of the flanging part is L3, and L3 is larger than or equal to 25% R0 and smaller than or equal to 34% R0. According to the utility model, through the arrangement of the flanging part, the fixing firmness degree of the positive current collecting plate and the roll core can be improved by utilizing the pressing of the flanging part on the positive current collecting plate, and the energy density and the safety performance of the battery can be considered by optimizing the covering width of the flanging part on the positive current collecting plate, so that the overall performance of the battery is effectively improved.

Description

A positive electrode current collector coated with rubber structure and a cylindrical secondary battery Technical Field

[0001] This utility model relates to the field of cylindrical secondary battery technology, and in particular to a positive electrode current collector coated with rubber structure and 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] Overmolding is an important step in the production of cylindrical batteries. By wrapping the core and current collector with an insulating material, not only can the core and current collector be fixed and supported, but the overall quality and performance of the battery cell can also be improved.

[0004] As disclosed in the invention patent CN116315139A, the method for preparing a tab-type battery cell involves welding current collectors to the positive and negative ends of a flattened core to obtain a tab-type core. The tab-type core is then fitted into an insulating film shell to achieve a coating process. To improve the stability of the insulating film shell in fixing the positive current collector, it needs to completely cover the positive current collector. However, if the area covered by the insulating film shell is too small, the shell may not be able to completely cover the core, and the edges may lift, reducing the reliability of the connection and increasing the risk of short circuits between the positive electrode and the shell, thus decreasing battery safety. If the area covered by the insulating film shell is too large, it increases the amount of insulating film material used, raising the battery manufacturing cost, increasing the battery weight, reducing the battery's energy density, and potentially covering the current collector's vent holes, affecting the battery's electrolyte filling and venting functions, and reducing battery safety performance. Summary of the Invention

[0005] In view of this, this utility model proposes a positive electrode current collector coating structure and a cylindrical secondary battery. By reasonably setting the coating width of the flange on the positive electrode current collector, the energy density and safety performance of the battery can be taken into account, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is achieved as follows: On the one hand, this utility model provides a positive electrode current collector coated structure, including coating and a positive electrode current collector, wherein,

[0007] The rubber coating is used to cover the outside of the core, and one end of the rubber coating has an integrally formed flange, which has a ring-shaped structure.

[0008] The positive current collector includes a disc body and a tail body, wherein the disc body of the positive current collector is abutted and fixed between the core and the flanged portion;

[0009] The radius of the positive current collector is R0, and the circumference width of the flange is L3, wherein 25%R0≤L3≤34%R0.

[0010] Based on the above technical solutions, the preferred value is L3 = 2.6mm-3.4mm.

[0011] Based on the above technical solutions, preferably, the positive electrode current collector has a central hole in the middle and a peripheral hole on the outer periphery of the positive electrode current collector.

[0012] The minimum distance between the outer hole and the flange is L2, where 3%R0≤L2≤9%R0.

[0013] More preferably, the minimum distance between the central hole and the peripheral hole is L1, wherein 8%R0≤L1≤14%R0.

[0014] More preferably, one end of the tail body is integrally formed on the disc body, and the end of the tail body near the disc body is a bent portion;

[0015] The minimum distance between the bent portion and the central hole is L4, where 25%R0≤L4≤34%R0.

[0016] More preferably, the minimum distance between the bent portion and the flanged portion is L5, wherein 13%R0≤L5≤20%R0.

[0017] More preferably, the radius of the central hole is R1, where R1 = 2.2mm-2.8mm.

[0018] More preferably, the radius of the peripheral hole is R2, where R2 = 1.2mm-1.8mm.

[0019] Based on the above technical solutions, the preferred value is R0 = 9.74mm-10.74mm.

[0020] Secondly, this utility model provides a cylindrical secondary battery, including the above-mentioned positive electrode current collector coated with rubber structure.

[0021] The positive electrode current collector coating structure and cylindrical secondary battery of this utility model have the following advantages over the prior art:

[0022] (1) By setting the flange, the positive current collector can be supported by it, which can improve the fixing firmness between the positive current collector and the core. By optimizing the coverage width of the flange on the positive current collector, the energy density and safety performance of the battery can be taken into account, thereby effectively improving the overall performance of the battery.

[0023] (2) By opening a central hole and a peripheral hole on the positive current collector, electrolyte can be conveniently injected into the core and the electrolyte can quickly penetrate the core. By setting the positive current collector to include a plate body and a tail body, the positive current collector can be quickly connected to the core and the cap assembly, thereby improving the battery assembly efficiency.

[0024] (3) By restricting the specifications and positions of the central hole, peripheral holes and bending parts, the energy density and safety performance of the battery can be further improved, ensuring the normal use of the battery. Attached Figure Description

[0025] 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.

[0026] Figure 1 is a top view of a positive current collector coated with rubber according to this utility model;

[0027] Figure 2 is a top view of the tail section in a positive current collector coating structure of this utility model;

[0028] Figure 3 is a top view of the positive current collector in the positive current collector coating structure of this utility model;

[0029] Figure 4 is a cross-sectional view of the coating section in a positive current collector coating structure of this utility model.

[0030] Among them: 1. Core; 2. Glue coating; 21. Flanged edge; 3. Positive current collector; 31. Disc body; 32. Tail body; 301. Center hole; 302. Outer hole; 303. Bending part. Detailed Implementation

[0031] 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.

[0032] Cylindrical secondary batteries are a type of rechargeable battery with advantages such as high safety, high energy density, and good charge and discharge performance. They are widely used in electric vehicles, electric two-wheelers, power tools, and other fields.

[0033] This utility model discloses a cylindrical secondary battery, comprising a core 1 and a positive current collector encapsulation structure. The positive current collector encapsulation structure includes an encapsulation 2 and a positive current collector 3. The encapsulation 2 is a sheath made of insulating material, such as polyimide, as shown in Figure 4. After the positive current collector 3 is fixedly connected to the positive electrode tab of the core 1, the encapsulation 2 is wrapped around the outside of the positive current collector 3 and the core 1. This not only provides an insulating layer for the core 1 and the positive current collector 3, effectively isolating short circuits between the core 1 and the positive current collector 3 and components such as the casing, but also fixes and supports the core 1 and the positive current collector 3, maintaining the stability of their connection. It also reduces the amount of electrolyte added, allowing the electrolyte to fully contact the core 1 and quickly penetrate it, thereby improving the overall performance of the battery.

[0034] As shown in Figure 1, one end of the rubber coating 2 is integrally formed with a flange 21, which has a ring-shaped structure.

[0035] As shown in Figure 3, the positive current collector 3 includes a disc body 31 and a tail body 32. The disc body 31 is used to weld to the positive electrode tab of the core 1 and to hold and fix it between the core 1 and the flange 21. One end of the tail body 32 is integrally formed on the disc body 31, and the other end of the tail body 32 passes through the flange 21 and is welded to the cap assembly. By using the flange 21 to hold the disc body 31 away from the core 1, the disc body 31 can be firmly attached to the core 1, avoiding relative displacement between the disc body 31 and the core 1.

[0036] The tail body 32 can be bent, and the end of the tail body 32 near the disc body 31 is the bent part 303.

[0037] The flange 21 is preferably in the shape of a ring to improve the support stability of the flange 21 on the positive current collector 3.

[0038] As shown in Figure 3, a central hole 301 is provided in the middle of the disc body 31 to inject electrolyte into the core 1 through the central hole 301. In order to allow the electrolyte to quickly penetrate the core 1, peripheral holes 302 are also provided on the outer periphery of the disc body 31. Preferably, multiple peripheral holes 302 are provided so that the electrolyte can be added to different positions of the core 1. At the same time, the gas generated in the core 1 can be discharged through the central hole 301 and peripheral holes 302, thereby avoiding the risk of explosion of the core 1.

[0039] To improve the battery's liquid injection and venting performance, it is preferable to arrange multiple peripheral holes 302 in a circumferential array around the center point of the central hole 301.

[0040] As shown in Figures 1-3, the radius of the positive current collector 3 is R0, the radius of the central hole 301 is R1, the radius of the outer hole 302 is R2, the minimum distance between the central hole 301 and the outer hole 302 is L1, the minimum distance between the outer hole 302 and the flange 21 is L2, and the ring width of the flange 21 is L3.

[0041] In some embodiments, R0 = 9.74mm-10.74mm, that is, the radius of the positive electrode current collector 3 is 9.74mm, 10.24mm or 10.74mm, etc., to meet the usage requirements of commonly used cylindrical secondary batteries.

[0042] In some embodiments, R1 = 2.2mm-2.8mm, that is, the radius of the central hole 301 is 2.2mm, 2.5mm, or 2.8mm, etc. If R1 < 2.2mm, the inner diameter of the central hole 301 is too small, making it difficult to inject electrolyte into the core 1. The electrolyte does not have enough channels to flow into the battery, reducing the injection efficiency. The positive current collector 3 is used to weld with the tab of the core 1. If R1 > 2.8mm, the inner diameter of the central hole 301 is too large, which will reduce the effective area on the positive current collector 3, resulting in a reduction in the weldable area on the positive current collector 3. When welding the positive current collector 3 and the positive tab of the core 1, the welding area between the positive current collector 3 and the positive tab of the core 1 is too small, and the temperature at the welding position increases, affecting the overall performance of the battery.

[0043] In some embodiments, R2 = 1.2mm-1.8mm, that is, the radius of the outer hole 302 is 1.2mm, 1.5mm, or 1.8mm, etc. If R2 < 1.2mm, the inner diameter of the outer hole 302 is too small, making it difficult to inject electrolyte into the core 1. The electrolyte does not have enough channels to flow into the battery, reducing the injection efficiency. The positive electrode current collector 3 is used to weld with the tab of the core 1. If R2 > 1.8mm, the inner diameter of the outer hole 302 is too large, which will reduce the effective area on the positive electrode current collector 3, resulting in a reduction in the weldable area on the positive electrode current collector 3. When welding the positive electrode current collector 3 and the positive electrode tab of the core 1, the welding area between the positive electrode current collector 3 and the positive electrode tab of the core 1 is too small, and the temperature at the welding position increases, affecting the overall performance of the battery.

[0044] In some embodiments, 8%R0≤L1≤14%R0, that is, the minimum distance between the central hole 301 and the peripheral hole 302 is 8%, 11% or 14% of the radius of the positive current collector 3, etc. If L1 < 8%R0, the distance between the central hole 301 and the peripheral hole 302 is too small, resulting in low structural strength at the position between the central hole 301 and the peripheral hole 302 on the positive current collector 3. During battery assembly, this position is prone to deformation and breakage, which will also cause deformation at the welding position of the positive current collector 3 and the positive electrode tab of the core 1, increasing the incidence of poor welding defects. If the position between the central hole 301 and the peripheral hole 302 on the positive current collector 3 breaks, metal debris is easily generated. After the metal debris moves to other positions, it will cause short circuits in other components, reducing the safety performance of the battery. If L1 > 14%R0, the distance between the central hole 301 and the peripheral hole 302 is too large, and the peripheral hole 302 is far away from the central hole 301. The flange 21 is prone to blocking the peripheral hole 302, affecting the liquid injection performance and venting performance of the peripheral hole 302, reducing the liquid injection efficiency and safety performance of the battery.

[0045] In some embodiments, 3%R0≤L2≤9%R0, that is, the minimum distance between the peripheral hole 302 and the flange 21 is 3%, 6% or 9% of the radius of the positive current collector 3. If L2 < 3%R0, the distance between the outer hole 302 and the flange 21 is too small, and the flange 21 is likely to block the outer hole 302, affecting the liquid injection and venting performance of the outer hole 302, and reducing the liquid injection efficiency and safety performance of the battery. If L2 > 9%R0, the distance between the outer hole 302 and the flange 21 is too large, and the outer hole 302 moves inward accordingly. The distance between the outer hole 302 and the center hole 301 is too small, resulting in low structural strength at the position between the center hole 301 and the outer hole 302 on the positive current collector 3. During the battery assembly process, this position is prone to deformation and breakage, which will also cause deformation at the welding position of the positive current collector 3 and the positive electrode tab of the core 1, increasing the incidence of poor welding defects. If the position between the center hole 301 and the outer hole 302 on the positive current collector 3 breaks, metal debris is likely to be generated. After the metal debris moves to other positions, it will cause short circuits in other components, reducing the safety performance of the battery.

[0046] In some embodiments, 25%R0≤L3≤34%R0, meaning the circumferential width of the flanged portion 21 is 25%, 30%, or 34% of the radius of the positive current collector 3. If L3<25%R0, the circumferential width of the flanged portion 21 is too small, resulting in insufficient support for the positive current collector 3 and causing the flanged portion 21 to warp. Simultaneously, the area covered by the positive current collector 3 is smaller, increasing the risk of short circuit between the positive current collector 3 and the casing, thus reducing battery safety. If L3>34%R0, the circumferential width of the flanged portion 21 is too large, increasing the amount of insulating material used, which not only increases the manufacturing cost of the battery but also increases its weight and reduces its energy density. Furthermore, an excessively large flanged portion 21 can easily obstruct the outer hole 302 and the central hole 301, affecting the battery's liquid injection and venting performance, and reducing battery safety.

[0047] In some embodiments, L3 = 2.6mm-3.4mm, that is, the circumference width of the flange 21 is 2.6mm, 3mm, or 3.4mm, etc. If L3 < 2.6mm, the circumference width of the flange 21 is too small, and the flange 21 is too narrow. The flange 21 cannot provide sufficient support for the positive electrode current collector 3, which will cause the flange 21 to lift up. At the same time, the area covered by the positive electrode current collector 3 is smaller, which increases the risk of short circuit between it and the casing and reduces the safety performance of the battery. If L3 > 3.4mm, the circumference width of the flange 21 is too large, which will increase the amount of insulating material used. This will not only increase the manufacturing cost of the battery, but also increase the weight of the battery and reduce the energy density of the battery. At the same time, the excessive width of the flange 21 can also easily block the outer hole 302 and the central hole 301, affecting the electrolyte injection performance and venting performance of the battery and reducing the safety performance of the battery.

[0048] As shown in Figures 1 and 2, the minimum distance between the bent part 303 and the center hole 301 is L4, and the minimum distance between the bent part 303 and the flange part 21 is L5.

[0049] In some embodiments, 25%R0≤L4≤34%R0, that is, the minimum distance between the bent portion 303 and the central hole 301 is 25%, 30% or 34% of the radius of the positive electrode current collector 3. The flattened positive electrode tab on the core 1 is located in the middle of the core 1. The middle of the disc 31 is welded to the positive electrode tab of the core 1 for conduction. If L4 < 25%R0, the distance between the bent part 303 and the center hole 301 is too small, and the end of the tail body 32 near the disc 31 is too close to the center hole 301. The disc 31 does not have enough current-carrying area. When conducting electricity, the battery temperature rises, which will reduce the battery's safety performance. When assembling the battery, an insulating ring needs to be fitted on the positive current collector 3. If L4 > 34%R0, the distance between the bent part 303 and the center hole 301 is too large. When assembling the insulating ring, the insulating ring will interfere with the bent part 303, leading to poor assembly and increasing the battery's defect rate.

[0050] In some embodiments, 13%R0≤L5≤20%R0, that is, the minimum distance between the bent portion 303 and the flanged portion 21 is 13%, 17%, or 20% of the radius of the positive current collector 3. When assembling the battery, an insulating ring needs to be fitted on the positive current collector 3. If L5<13%R0, the distance between the bent portion 303 and the flanged portion 21 is too small. When assembling the insulating ring, the insulating ring will interfere with the bent portion 303, resulting in poor assembly and increasing the battery defect rate. The flattened positive electrode tab on the core 1 is located in the middle of the core 1, and the middle position of the disc body 31 is welded to the positive electrode tab of the core 1 for conduction. If L5>20%R0, the distance between the bent portion 303 and the flanged portion 21 is too large, and the end of the tail body 32 near the disc body 31 is too close to the center hole 301. The disc body 31 does not have enough current-carrying area. When conducting electricity, the battery temperature rises, which will reduce the battery safety performance.

[0051] In some embodiments, R0 = 10.24 mm, R1 = 2.5 mm, R2 = 1.5 mm, L1 = 11%R0, L2 = 6%R0, and L3 = 29%R0, which can ensure the reliability of the connection between the flange 21 and the positive electrode current collector 3 and the structural strength of the plate body 31, and can also facilitate the improvement of the battery's liquid injection and venting capabilities, as well as increase the battery's energy density and improve the overall performance of the battery; L4 = 30%R0 and L5 = 17%R0, so as to facilitate battery assembly and ensure the battery's overcurrent capability.

[0052] The working principle of the positive electrode current collector coated structure and the cylindrical secondary battery of this utility model is as follows:

[0053] As shown in Figure 3, the positive current collector 3 includes a disc body 31 and a tail body 32. The tail body 32 can be bent to enable welding operations between the disc body 31 and the positive electrode tab of the core 1, as well as welding operations between the tail body 32 and the cap assembly, thereby improving the battery assembly efficiency. The disc body 31 has a central hole 301 and a peripheral hole 302 to enable electrolyte filling and gas discharge, ensuring normal battery use. As shown in Figure 4, the adhesive 2 covers the core 1 and the disc body 31. As shown in Figure 1, the flange 21 covers the side of the disc body 31 away from the core 1, thereby providing stable support and wrapping for the core 1 and the positive current collector 3, ensuring the overall performance of the battery.

[0054] 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 positive electrode current collector coated with adhesive, characterized in that: The device includes a rubber coating (2) and a positive current collector (3). The rubber coating (2) is used to fit around the outside of the core (1). One end of the rubber coating (2) is integrally formed with a flange (21), which has an annular structure. The positive current collector (3) includes a disc body (31) and a tail body (32). The disc body (31) of the positive current collector (3) is fixed between the core (1) and the flange (21). The radius of the disc body (31) of the positive current collector (3) is R0, and the ring width of the flange (21) is L3, wherein 25%R0≤L3≤34%R0.

2. The positive electrode current collector coating structure as described in claim 1, characterized in that: L3 = 2.6mm - 3.4mm.

3. The positive electrode current collector coating structure as described in claim 1, characterized in that: The positive current collector (3) has a central hole (301) in the middle and a peripheral hole (302) on the outer periphery of the positive current collector (3); the minimum distance between the peripheral hole (302) and the flange (21) is L2, wherein 3%R0≤L2≤9%R0.

4. The positive electrode current collector coating structure as described in claim 3, characterized in that: The minimum distance between the central hole (301) and the peripheral hole (302) is L1, wherein 8%R0≤L1≤14%R0.

5. The positive electrode current collector coating structure as described in claim 3, characterized in that: One end of the tail body (32) is integrally formed on the disc body (31), and the end of the tail body (32) near the disc body (31) is a bent part (303); the minimum distance between the bent part (303) and the center hole (301) is L4, wherein 25%R0≤L4≤34%R0.

6. The positive electrode current collector coating structure as described in claim 5, characterized in that: The minimum distance between the bent portion (303) and the flanged portion (21) is L5, wherein 13%R0≤L5≤20%R0.

7. The positive electrode current collector coating structure as described in claim 3, characterized in that: The radius of the central hole (301) is R1, where R1 = 2.2mm - 2.8mm.

8. The positive electrode current collector coating structure as described in claim 7, characterized in that: The radius of the peripheral hole (302) is R2, where R2 = 1.2mm - 1.8mm.

9. A positive electrode current collector coated structure as described in any one of claims 1-8, characterized in that: R0 = 9.74mm - 10.74mm.

10. A cylindrical secondary battery, characterized in that: Including the positive current collector coated structure as described in any one of claims 1-9.

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