Annular lithium ion battery

Abstract

The utility model discloses an annular lithium ion battery, the annular lithium ion battery comprises a battery shell and a battery cell arranged in the battery shell, the battery cell comprises a positive pole piece, a negative pole piece and a diaphragm, the battery cell further comprises an annular pole lug with a hollow structure, and a heat dissipation channel is formed in the annular pole lug; the annular tab comprises a positive tab and a negative tab which are arranged at the two ends of the annular tab, and an insulating connecting section for connecting the positive tab and the negative tab, and the positive tab, the negative tab and the insulating connecting section are of an integrated structure; the positive pole piece wraps the outer side of the positive pole lug, the positive pole lug is higher than the positive pole piece, the negative pole piece wraps the outer side of the negative pole lug, the negative pole lug is higher than the negative pole piece, the positive pole lug is in contact with the positive pole piece, and the negative pole lug is in contact with the negative pole piece; and the positive pole piece, the negative pole piece and the diaphragm are wound on the annular tab. According to the annular lithium ion battery, the heat dissipation effect is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a ring-shaped lithium-ion battery. Background Art

[0002] Lithium-ion batteries (Li-ion batteries) are a type of rechargeable battery technology widely used in various portable electronic devices, electric vehicles, energy storage systems, and more. Known for their high energy density, long lifespan, and low self-discharge rate, Li-ion batteries are one of the most popular types of batteries on the market.

[0003] Currently, lithium-ion batteries can be categorized into cylindrical, prismatic, soft-pack, and special-shaped types based on their shape and packaging. In recent years, with the widespread adoption of wearable electronic products such as VR, fitness trackers, electronic rings, and health monitoring devices, the deformability requirements for their accompanying mobile power supplies have become increasingly stringent. Conventional soft-pack prismatic lithium-ion batteries, however, struggle to meet the structural and dimensional requirements of these circular or cylindrical electronic products.

[0004] The prior art discloses a wound lithium-ion secondary battery that uses winding needles as positive and negative electrodes. The lithium-ion battery uses tabs as winding needles to achieve cell winding during design, and the cell structure is hollow, similar to a tubular cell. This solution meets the needs of annular or cylindrical electronic products through the design of a hollow cell. However, in this solution, the ends of the tubular cell are sealed during the design of the tab structure, resulting in poor overall heat dissipation of the battery.

[0005] Therefore, how to provide a lithium-ion battery with a new structure to improve the heat dissipation effect of the lithium-ion battery has become a problem that needs to be solved urgently. Utility Model Content

[0006] The embodiment of the present application provides a ring-shaped lithium-ion battery to improve the heat dissipation effect of the lithium-ion battery.

[0007] The present application provides a ring-shaped lithium-ion battery, comprising: a battery housing, a battery cell disposed within the battery housing, the battery cell comprising a positive electrode sheet, a negative electrode sheet, and a separator, the separator being used to electrically isolate the positive electrode sheet from the negative electrode sheet, the battery cell further comprising: an annular electrode tab having a hollow interior, the interior of which forms a heat dissipation channel;

[0008] The annular tab includes: a positive tab and a negative tab provided at both ends of the annular tab, and an insulating connecting section connecting the positive tab and the negative tab, wherein the positive tab, the negative tab and the insulating connecting section are an integral structure; the positive electrode sheet is wrapped around the outside of the positive tab, and the height of the positive tab is higher than the height of the positive electrode sheet; the negative electrode sheet is wrapped around the outside of the negative tab, and the height of the negative electrode tab is higher than the height of the negative electrode sheet; the positive tab is in contact with the positive tab, and the negative tab is in contact with the negative tab;

[0009] The positive electrode sheet, the negative electrode sheet and the separator are wound on the annular tab.

[0010] Optionally, the positive electrode tab is welded or crimped with the positive electrode sheet, and the negative electrode tab is welded or crimped with the negative electrode sheet.

[0011] Optionally, the insulating connecting section and the negative electrode tab and the positive electrode tab are bonded together by an adhesive.

[0012] Optionally, a sealant for encapsulating the battery housing and the battery cell is provided on a metal edge of the positive electrode tab away from the insulating connecting section and a metal edge of the negative electrode tab away from the insulating connecting section.

[0013] Optionally, the sealant comprises a polypropylene resin layer having metal affinity modification, a polypropylene skeleton layer, and a polypropylene layer having resin affinity modification;

[0014] The polypropylene resin layer is arranged in the inner layer of the sealant, and the inner layer is close to the metal edge;

[0015] The polypropylene skeleton layer is arranged in the middle layer of the sealant;

[0016] The polypropylene layer is arranged on the outer layer of the sealant.

[0017] Optionally, the positive electrode plate includes a positive electrode coating portion and a positive electrode non-coating portion, wherein the positive electrode non-coating portion is located at edges of two opposite sides of the positive electrode plate along the winding direction and is electrically connected to the positive electrode tab at multiple locations;

[0018] The negative electrode plate includes a negative electrode coating portion and a negative electrode non-coating portion. The negative electrode non-coating portion is located at edges of two opposite sides of the negative electrode plate along a winding direction and is electrically connected to the negative electrode tab at multiple locations.

[0019] Optionally, the inner diameter of the positive electrode tab, the inner diameter of the insulating connecting section and the inner diameter of the negative electrode tab are the same, the difference between the outer diameter of the insulating connecting section and the outer diameter of the positive electrode tab is a first difference, and the difference between the outer diameter of the insulating connecting section and the outer diameter of the negative electrode tab is a second difference, and both the first difference and the second difference are less than a preset threshold.

[0020] Optionally, when the outer diameter of the positive electrode tab is the same as the outer diameter of the negative electrode tab, the first difference and the second difference are both 0.008 to 0.025 mm;

[0021] When the outer diameter of the positive electrode tab is different from the outer diameter of the negative electrode tab, the first difference is 0.008 to 0.025 mm, and the second difference is 0.0045 to 0.025 mm.

[0022] Optionally, the interior of the battery core is a hollow structure, and both ends of the battery core are open;

[0023] Alternatively, the interior of the battery core is a hollow structure, and any one of the two ends of the battery core is open.

[0024] Optionally, when both ends of the battery core are open, the heat dissipation channel is oriented toward both ends of the annular tab;

[0025] Alternatively, when any one of the two ends of the battery core is open, the heat dissipation channel is directed toward any one of the two ends of the annular tab.

[0026] Optionally, the positive electrode sheet, the negative electrode sheet, and the separator are wound on the annular tab, including:

[0027] The positive electrode sheet, the separator, the negative electrode sheet and the separator are sequentially wound on the annular tab.

[0028] Compared with the prior art, the embodiments of the present application have the following advantages:

[0029] The embodiment of the present application provides a ring-shaped lithium-ion battery, comprising: a battery housing, a battery cell disposed in the battery housing, the battery cell comprising a positive electrode sheet, a negative electrode sheet, and a diaphragm, the diaphragm being used to electrically isolate the positive electrode sheet from the negative electrode sheet, the battery cell further comprising: an annular pole ear with a hollow structure inside, and forming a heat dissipation channel inside the annular pole ear; the annular pole ear comprising: a positive pole ear and a negative pole ear disposed at both ends of the annular pole ear, and an insulating connecting section connecting the positive pole ear and the negative pole ear, and The positive electrode tab, the negative electrode tab and the insulating connecting section are an integrated structure; the positive electrode sheet is wrapped around the outside of the positive electrode tab, and the height of the positive electrode tab is higher than the height of the positive electrode sheet, the negative electrode sheet is wrapped around the outside of the negative electrode tab, and the height of the negative electrode tab is higher than the height of the negative electrode sheet, the positive electrode tab is in contact with the positive electrode sheet, and the negative electrode tab is in contact with the negative electrode sheet; the positive electrode sheet, the negative electrode sheet and the diaphragm are wound on the annular tab.

[0030] The ring-shaped lithium-ion battery described in the embodiments of the present application solves the problem of inconsistent heat dissipation between the inner and outer layers of traditional lithium-ion battery cells. The ring-shaped tabs, designed with an internal hollow structure, form heat dissipation channels within the tabs, which can accelerate the heat dissipation effect of the inner layer of the battery cell, thereby improving the heat dissipation of the lithium-ion battery. At the same time, it can also reduce the thermal runaway problem caused by diaphragm shrinkage due to heat accumulation within the battery cell, thereby improving the heat resistance and stability of the lithium-ion battery. Furthermore, the hollow structure inside the ring-shaped lithium-ion battery also has better stress relief performance when responding to mechanical impact, which can eliminate the risk of internal short circuits caused by metal piercing the diaphragm due to stress concentration, thereby improving safety.

[0031] By using the ring-shaped tab as the winding needle support, the problem of misalignment between the positive and negative electrode sheets caused by needle withdrawal in traditional winding processes is resolved, which helps improve the consistency of lithium-ion batteries. Furthermore, this ring-shaped lithium-ion battery can meet the mobile power needs of ring-shaped electronic products, extending its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the annular tab in the ring-type lithium-ion battery provided in the embodiment of the present application;

[0033] Figure 2 This is a schematic diagram of the cell structure of a ring-type lithium-ion battery provided in an embodiment of the present application;

[0034] Figure 3 Schematic diagram of the winding of a ring-shaped lithium-ion battery cell provided in an embodiment of the present application;

[0035] Figure 4 This is a schematic diagram of a packaged ring-shaped lithium-ion battery provided in an embodiment of the present application;

[0036] Figure 5 Schematic diagram of the structure of the positive electrode sheet and the negative electrode sheet in the ring-type lithium-ion battery provided in the embodiment of the present application;

[0037] Figure 6 Schematic diagram of the layered structure of the sealant provided in the embodiment of the present application.

[0038] Reference numerals: 10-annular tab, 11-positive tab, 12-negative tab, 13-insulating connecting section, 14-sealant, 15-positive electrode sheet, 16-negative electrode sheet, 17-diaphragm, 18-battery housing, 141-polypropylene resin layer, 142-polypropylene skeleton layer, 143-polypropylene layer, 151-positive electrode active material, 161-negative electrode active material, 152-green glue DETAILED DESCRIPTION

[0039] The following description sets forth many specific details to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the scope of the present application. Therefore, the present application is not limited to the specific implementations disclosed below.

[0040] Lithium-ion batteries (Li-ion batteries) are a type of rechargeable battery technology widely used in various portable electronic devices, electric vehicles, energy storage systems, and more. Known for their high energy density, long lifespan, and low self-discharge rate, Li-ion batteries are one of the most popular types of batteries on the market.

[0041] Currently, lithium-ion batteries can be categorized into cylindrical, prismatic, soft-pack, and special-shaped types based on their shape and packaging. In recent years, with the widespread adoption of wearable electronic products such as VR, fitness trackers, electronic rings, and health monitoring devices, the deformability requirements for their accompanying mobile power supplies have become increasingly stringent. Conventional soft-pack prismatic lithium-ion batteries, however, struggle to meet the structural and dimensional requirements of these circular or cylindrical electronic products.

[0042] Therefore, in order to meet the power supply needs of electronic products with increasingly complex shapes, developing a lithium-ion battery that can meet the needs of annular or cylindrical electronic products has become an urgent problem that needs to be solved.

[0043] Based on this, the embodiments of the present application provide a ring-type lithium-ion battery to meet the demand for power sources for electronic products with increasingly complex shapes. The ring-type lithium-ion battery can specifically be a circular or tubular lithium-ion battery. However, the main difficulty in the production of circular or tubular lithium-ion batteries lies in the stability of the battery structure. The cell structure needs to have a high self-supporting ability to ensure the application stability of the cell. In addition, the process of manufacturing the cell also presents great challenges. Therefore, for the ring-type lithium-ion battery, the tab welding and packaging process needs to be significantly improved and enhanced compared to the production process of conventional lithium-ion batteries.

[0044] Currently, there is limited research on toroidal lithium-ion batteries. Prior art discloses a wound lithium-ion secondary battery that uses winding pins as positive and negative electrodes. This lithium-ion battery design uses the tabs as winding pins to achieve cell winding, and the cell structure is hollow, similar to a tubular cell. This hollow cell design meets the needs of toroidal or cylindrical electronic products. However, the tab design seals both ends of the tubular cell, resulting in poor overall heat dissipation, which seriously affects its application.

[0045] Based on this, the applicant proposed to improve the heat dissipation performance of lithium-ion batteries by improving the structure and winding method of the tabs. This application designs an annular tab inside the battery cell as a support for the battery cell. The annular tab has a hollow structure and forms a heat dissipation channel inside. The annular tab includes: a positive tab and a negative tab arranged at both ends of the annular tab, and an insulating connecting section connecting the positive and negative tabs. The positive tab, negative tab and insulating connecting section are an integrated structure.

[0046] During winding, the positive electrode sheet, separator, negative electrode sheet, and separator are wound around the annular tab. Specifically, the positive electrode sheet can be wrapped around the outside of the positive tab, and the positive tab is higher than the positive electrode sheet. The negative electrode sheet can be wrapped around the outside of the negative tab, and the negative tab is higher than the negative electrode sheet. The positive tabs are in contact with the positive electrode sheet, and the negative tabs are in contact with the negative electrode sheet. This winding method is beneficial for improving the alignment of the positive and negative electrode sheets and improving the core yield. It also avoids the core pulling and misalignment of the positive and negative electrode sheets during existing winding. In addition, this annular or tubular lithium-ion battery has better internal heat dissipation performance and higher safety.

[0047] Therefore, the annular lithium-ion battery provided in the present application not only improves the heat dissipation of the lithium-ion battery and is safer, but also improves the consistency of the lithium-ion battery by using an annular tab as a battery cell support. At the same time, the annular lithium-ion battery can meet the demand for mobile power supplies for annular electronic products and has a wider range of applications.

[0048] The following combination Figures 1-6The structure of the ring-type lithium-ion battery provided in this application is introduced in detail.

[0049] The annular lithium-ion battery comprises: a battery housing, a battery cell disposed within the battery housing, the battery cell comprising a positive electrode sheet, a negative electrode sheet, and a separator, the separator being used to electrically isolate the positive electrode sheet from the negative electrode sheet. In the embodiment of the present application, the battery cell further comprises: an annular tab 10 having a hollow interior, the interior of which constitutes a heat dissipation channel for the annular lithium-ion battery. Figure 1 , Figure 1 This is a schematic diagram of the structure of an annular tab in a ring-type lithium-ion battery provided in an embodiment of the present application. The annular tab 10 includes: a positive tab 11 and a negative tab 12 provided at both ends of the annular tab 10, and an insulating connecting segment 13 connecting the positive tab 11 and the negative tab 12. The positive tab 11, the negative tab 12, and the insulating connecting segment 13 are integrally structured. The insulating connecting segment 13 and the negative tab 12 and the positive tab 11 are bonded to each other by an adhesive, which is an epoxy resin adhesive.

[0050] When winding, see Figure 2 , Figure 2 This is a schematic diagram of the cell structure of a ring-shaped lithium-ion battery provided in an embodiment of the present application. The positive electrode sheet 15, the negative electrode sheet 16, and the separator 17 are wound around the ring-shaped tab 10. The positive electrode sheet 15 is wrapped around the outside of the positive electrode tab 11, and the height of the positive electrode tab 11 is higher than that of the positive electrode sheet 15. The negative electrode sheet 16 is wrapped around the outside of the negative electrode tab 12, and the height of the negative electrode tab 12 is higher than that of the negative electrode sheet 16. The positive electrode tab 11 is in contact with the positive electrode sheet 15, and the negative electrode tab 12 is in contact with the negative electrode sheet 16. The contact between the positive electrode tab 11 and the positive electrode sheet 15, and the contact between the negative electrode tab 12 and the negative electrode sheet 16 can be specifically that the positive electrode sheet 15 is welded or crimped onto the positive electrode tab 11, and the negative electrode sheet 16 is welded or crimped onto the negative electrode tab 12.

[0051] It should be noted that the annular lithium-ion battery can be a circular lithium-ion battery or a tubular lithium-ion battery in a specific implementation. Correspondingly, the annular tabs can also be annular tabs or tubular tabs. The annular lithium-ion battery corresponds to an annular tab, and the tubular lithium-ion battery corresponds to a tubular tab. In a specific implementation, the positive electrode tab 11 is an aluminum tab, the insulating connecting section 13 is an insulating resin, and the negative electrode tab 12 is a nickel tab. When the lithium-ion battery is placed with the positive electrode facing upward and the negative electrode facing downward, the annular / tubular tabs are composed of an annular aluminum tab, an annular insulating resin, and an annular nickel tab from top to bottom.

[0052] See Figure 3 , Figure 3 This is a schematic diagram of the winding of a ring-shaped lithium-ion battery cell provided in an embodiment of the present application. When the positive electrode sheet 15, the negative electrode sheet 16, and the separator 17 are wound on the ring-shaped tab 10, specifically, the positive electrode sheet 15, the separator 17, the negative electrode sheet 16, and the separator 17 are wound on the ring-shaped tab 10 in sequence. In addition, the height of the positive electrode tab 11 is higher than the height of the positive electrode sheet 15, and the height of the negative electrode tab 12 is higher than the height of the negative electrode sheet 16. In specific use, the portion of the positive electrode tab 11 that is higher than the positive electrode sheet 15 and the portion of the negative electrode tab 12 that is higher than the negative electrode sheet 16 are used to electrically connect to a preset interface on an electronic product.

[0053] It should be noted that the interior of the annular tab 10 is a hollow structure, and a heat dissipation channel is formed therein. In this application, the battery cell is a hollow structure with both ends of the battery cell being open, or the battery cell is a hollow structure with either end of the battery cell being open. When both ends of the battery cell are open, the heat dissipation channel is oriented toward the ends of the annular tab 10; or, when either end of the battery cell is open, the heat dissipation channel is oriented toward either end of the annular tab 10.

[0054] In a specific implementation, the inner diameter of the positive electrode tab 11, the inner diameter of the insulating connecting section 13, and the inner diameter of the negative electrode tab 12 are the same. The difference between the outer diameter of the insulating connecting section 13 and the outer diameter of the positive electrode tab 11 is a first difference, and the difference between the outer diameter of the insulating connecting section 13 and the outer diameter of the negative electrode tab 12 is a second difference. Both the first difference and the second difference are less than a preset threshold. When the outer diameters of the positive electrode tab 11 and the negative electrode tab 12 are the same, the first difference and the second difference are both 0.008 to 0.025 mm. When the outer diameters of the positive electrode tab 11 and the negative electrode tab 12 are different, the first difference is 0.008 to 0.025 mm, and the second difference is 0.0045 to 0.025 mm.

[0055] It should be noted that the inner diameters of the positive electrode tab 11, the insulating connecting section 13 and the negative electrode tab 12 are consistent, and the outer diameters of the annular aluminum tab (dAluminum) and the annular nickel tab (dNickel) are slightly smaller than the annular insulating resin (dInsulation). Figure 1 By thinning the outer diameter of the positive and negative electrode ring ears, the problems of excessive thickness and inconsistent winding thickness caused by current collector welding can be solved.

[0056] For specific implementation, please continue to refer to Figure 3The metal edge of the positive electrode tab 11 away from the insulating connecting section 13 and the metal edge of the negative electrode tab 12 away from the insulating connecting section 13 are provided with a sealant 14 for sealing the battery shell and the battery cell. The schematic diagram of the ring-shaped lithium-ion battery after packaging can be seen in Figure 4 , Figure 4 This is a schematic diagram of the packaged ring-shaped lithium-ion battery provided in the embodiment of the present application. The battery housing 18 and the battery cell are sealed by a sealant 14. The composition of the sealant 14 can be found in Figure 6 , Figure 6 This is a schematic diagram of the layered structure of the sealant provided in an embodiment of the present application, wherein the sealant 14 includes a metal-affinity modified polypropylene resin layer 141, a polypropylene skeleton layer 142, and a resin-affinity modified polypropylene layer 143; the polypropylene resin layer 141 is arranged in the inner layer of the sealant 14, and the inner layer is close to the metal edge; the polypropylene skeleton layer 142 is arranged in the middle layer of the sealant 14; and the polypropylene layer 143 is arranged in the outer layer of the sealant 14.

[0057] It should be noted that a ring of sealant 14 is adhered to the top of the aluminum and nickel tabs. This sealant 14 can specifically be a sealing melt adhesive. This sealing melt adhesive is composed of three layers of melt-coextruded modified polypropylene (PP). Among them, the layer near the metal tab side is a PP resin with metal affinity modification, the middle layer is a PP skeleton layer, and the outer layer is a resin-friendly modified PP. The modified PP can also be a modified PP resin with a low melting point. Using a low-melting-point modified PP resin can reduce packaging process conditions and can pre-melt and crack in the face of thermal abuse, acting as a pressure relief valve to avoid fire and explosion accidents.

[0058] The sealant 14 is pre-heated and pressed to achieve a preliminary fixation, allowing the aluminum-plastic film / steel shell / aluminum shell to be sealed with the battery cell during top sealing. The design of the sealant ring not only serves as a winding alignment reference, but also helps to reduce the mechanical impact of the hot press on the annular / tubular tabs during melt packaging.

[0059] In the embodiment of the present application, the positive electrode sheet 15 includes a positive electrode coating portion and a positive electrode non-coating portion, the positive electrode non-coating portion is located at the edges of the two opposite sides of the positive electrode sheet 15 along the winding direction, and is electrically connected to the positive electrode tab 11 at multiple locations; the negative electrode sheet 16 includes a negative electrode coating portion and a negative electrode non-coating portion, the negative electrode non-coating portion is located at the edges of the two opposite sides of the negative electrode sheet 16 along the winding direction, and is electrically connected to the negative electrode tab 12 at multiple locations. Among them, the positive electrode sheet 15 is an aluminum foil current collector, and the negative electrode sheet 16 is a copper foil current collector. The structures of the positive electrode sheet 15 and the negative electrode sheet 16 can be seen in Figure 5 , Figure 5 It is a structural diagram of the positive electrode and negative electrode in the annular lithium-ion battery provided in the embodiment of the present application. The positive electrode 15 is coated with a positive electrode active material 151, and the negative electrode 16 is coated with a negative electrode active material 161. It should be noted that a green glue 152 is also provided on the positive electrode 15. When winding, the positive electrode 15 is first wound on the annular tab 10, and the green glue 152 is affixed to the inner side of the first winding of the positive electrode 15. This can achieve aluminum foil protection and insulation between the inner ring of the tab and the tab. In addition, the positive electrode 15 has the highest energy density at the innermost side and the cheapest material price. Through the structural design of the annular tab, the effective welding area between the annular / tubular tab and the current collector can be effectively improved, the electron conduction capability is improved, and it is beneficial to improve the rate performance of the lithium-ion battery.

[0060] The above is a detailed introduction to the ring-type lithium-ion battery structure provided by the present application. The ring-type lithium-ion battery comprises: a battery shell, a battery cell arranged in the battery shell, the battery cell comprises a positive electrode sheet, a negative electrode sheet and a diaphragm, the diaphragm is used to electrically isolate the positive electrode sheet and the negative electrode sheet, the battery cell further comprises: an annular pole ear with a hollow structure inside, and a heat dissipation channel is formed inside the annular pole ear; the annular pole ear comprises: a positive pole ear and a negative pole ear arranged at both ends of the annular pole ear, and a connection between the positive pole ear and the negative pole ear. The positive electrode tab, the negative electrode tab and the insulating connecting section are an integrated structure; the positive electrode sheet is wrapped around the outside of the positive electrode tab, and the height of the positive electrode tab is higher than the height of the positive electrode sheet, the negative electrode sheet is wrapped around the outside of the negative electrode tab, and the height of the negative electrode tab is higher than the height of the negative electrode sheet, the positive electrode tab is in contact with the positive electrode sheet, and the negative electrode tab is in contact with the negative electrode sheet; the positive electrode sheet, the negative electrode sheet and the diaphragm are wound on the annular tab.

[0061] The ring-shaped lithium-ion battery described in the embodiments of the present application solves the problem of inconsistent heat dissipation between the inner and outer layers of traditional lithium-ion battery cells. The ring-shaped tabs, designed with an internal hollow structure, form heat dissipation channels within the tabs, which can accelerate the heat dissipation effect of the inner layer of the battery cell, thereby improving the heat dissipation of the lithium-ion battery. At the same time, it can also reduce the thermal runaway problem caused by diaphragm shrinkage due to heat accumulation within the battery cell, thereby improving the heat resistance and stability of the lithium-ion battery. Furthermore, the hollow structure inside the ring-shaped lithium-ion battery also has better stress relief performance when responding to mechanical impact, which can eliminate the risk of internal short circuits caused by metal piercing the diaphragm due to stress concentration, thereby improving safety.

[0062] By using ring-shaped tabs as the cell support, the problem of misalignment between the positive and negative electrode sheets caused by needle withdrawal in traditional winding processes is resolved, which helps improve the consistency of lithium-ion batteries. Furthermore, this ring-shaped lithium-ion battery can meet the mobile power needs of ring-shaped electronic products, extending its application range.

[0063] When designing the ring-type tab structure, the outer diameters of the positive and negative tabs are smaller than the outer diameter of the insulating resin ring, which is beneficial to improving the flatness of the battery cell structure and reducing the probability of deformation of the lithium-ion battery.

[0064] The design of the annular pole ear with a hollow structure and an internal heat dissipation channel, as well as the design of open ends at both ends of the battery cell, is conducive to increasing the effective welding area between the annular pole ear and the current collector, improving the electron conductivity, and helping to improve the rate performance of the lithium-ion battery; in addition, the internal hollow structure of the annular lithium-ion battery is conducive to achieving the heat dissipation capacity inside the battery cell, which has an improving effect on positive and negative electrode materials with poor high-temperature performance.

[0065] Although the present application is disclosed as above with the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A ring-type lithium-ion battery comprising: A battery housing, and a battery cell disposed in the battery housing, wherein the battery cell comprises a positive electrode sheet, a negative electrode sheet, and a diaphragm, wherein the diaphragm is used to electrically isolate the positive electrode sheet from the negative electrode sheet, and wherein the battery cell further comprises: an annular electrode ear having a hollow structure inside, and forming a heat dissipation channel inside the ear; The annular tab includes: a positive tab and a negative tab provided at both ends of the annular tab, and an insulating connecting section connecting the positive tab and the negative tab, wherein the positive tab, the negative tab and the insulating connecting section are an integrated structure; The positive electrode sheet is wrapped around the outside of the positive electrode tab, and the height of the positive electrode tab is higher than the height of the positive electrode sheet. The negative electrode sheet is wrapped around the outside of the negative electrode tab, and the height of the negative electrode tab is higher than the height of the negative electrode sheet. The positive electrode tab is in contact with the positive electrode sheet, and the negative electrode tab is in contact with the negative electrode sheet. The positive electrode sheet, the negative electrode sheet and the separator are wound on the annular tab.

2. The ring-type lithium-ion battery according to claim 1, characterized in that The positive electrode tab is welded or pressed onto the positive electrode sheet, and the negative electrode tab is welded or pressed onto the negative electrode sheet.

3. The ring-type lithium-ion battery according to claim 1, characterized in that The metal edge of the positive electrode tab away from the insulating connection section and the metal edge of the negative electrode tab away from the insulating connection section are provided with a sealant for encapsulating the battery shell and the battery core.

4. The ring-type lithium-ion battery according to claim 3, characterized in that The sealant comprises a polypropylene resin layer with metal affinity modification, a polypropylene skeleton layer and a polypropylene layer with resin affinity modification; The polypropylene resin layer is arranged in the inner layer of the sealant, and the inner layer is close to the metal edge; The polypropylene skeleton layer is arranged in the middle layer of the sealant; The polypropylene layer is arranged on the outer layer of the sealant.

5. The ring-type lithium-ion battery according to claim 1, characterized in that The positive electrode sheet includes a positive electrode coating portion and a positive electrode non-coating portion, wherein the positive electrode non-coating portion is located at edges of two opposite sides of the positive electrode sheet along the winding direction and is electrically connected to the positive electrode tab at multiple locations; The negative electrode plate includes a negative electrode coating portion and a negative electrode non-coating portion. The negative electrode non-coating portion is located at edges of two opposite sides of the negative electrode plate along a winding direction and is electrically connected to the negative electrode tab at multiple locations.

6. The ring-type lithium-ion battery according to claim 1, characterized in that The inner diameter of the positive electrode tab, the inner diameter of the insulating connecting section and the inner diameter of the negative electrode tab are the same, the difference between the outer diameter of the insulating connecting section and the outer diameter of the positive electrode tab is a first difference, and the difference between the outer diameter of the insulating connecting section and the outer diameter of the negative electrode tab is a second difference, and both the first difference and the second difference are less than a preset threshold.

7. The ring-type lithium-ion battery according to claim 6, characterized in that: When the outer diameter of the positive electrode tab is the same as the outer diameter of the negative electrode tab, the first difference and the second difference are both 0.008 to 0.025 mm; When the outer diameter of the positive electrode tab is different from the outer diameter of the negative electrode tab, the first difference is 0.008 to 0.025 mm, and the second difference is 0.0045 to 0.025 mm.

8. The ring-type lithium-ion battery according to claim 1, characterized in that: The interior of the battery core is a hollow structure, and both ends of the battery core are open; Alternatively, the interior of the battery core is a hollow structure, and any one of the two ends of the battery core is open.

9. The ring-type lithium-ion battery according to claim 8, characterized in that: When both ends of the battery core are open, the heat dissipation channel is oriented toward the two ends of the annular tab; Alternatively, when any one of the two ends of the battery core is open, the heat dissipation channel is directed toward any one of the two ends of the annular tab.

10. The ring-type lithium-ion battery according to claim 1, characterized in that: The positive electrode sheet, the negative electrode sheet and the diaphragm are wound on the annular tab, comprising: The positive electrode sheet, the separator, the negative electrode sheet and the separator are sequentially wound on the annular tab.

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