A winding core structure and a cylindrical battery

Abstract

This application provides a wound core structure and a cylindrical battery. The wound core structure includes a wound core body, a first busbar, a first tab, and a first conductive sheet. The first busbar is located at the first end of the wound core body. The side of the first busbar facing away from the wound core body has a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the first busbar, and the tab area is located in the outer ring area of ​​the first busbar and surrounds the tabless area. One end of the first tab is fixedly connected to the wound core body, and the other end is fixedly welded to the tab area of ​​the first busbar. The first conductive sheet is fixedly connected to the tabless area of ​​the first busbar. Thus, by fixing the first conductive sheet in the inner ring area of ​​the first busbar, the internal resistance of the wound core structure can be reduced to improve current transmission capability. Furthermore, when the welding area of ​​the first tab expands, the risk of short circuit caused by the first busbar being burned through and the separator melting can be effectively reduced.

Description

Technical Field

[0001] This application relates to the field of cylindrical battery technology, and more particularly to a core structure and a cylindrical battery. Background Technology

[0002] In cylindrical batteries, the core structure is the core component for energy storage and output. Its performance directly determines the battery's energy density, charge and discharge efficiency, and safety. To achieve efficient current output, it is necessary to use the cooperation of tabs and busbars to collect the current.

[0003] In related technologies, the busbar is a key component for current collection. It is fixed to the tab by welding, and the welding area of ​​the tab on the busbar is concentrated in the outer ring area, while the inner ring area is a tabless area. However, due to the limited area of ​​the outer ring area, the welding area between the tab and the outer ring area of ​​the busbar is limited. If the welding area is expanded, it will cause the inner ring area to be welded through and melt the isolation film, which can easily cause a short circuit. In addition, when the current is transmitted from the tab to the busbar, the internal resistance of the busbar is large and the current transmission capability is poor. Utility Model Content

[0004] This application provides a wound core structure and a cylindrical battery to at least solve the aforementioned problems in the related art.

[0005] To achieve the above objectives, this application provides the following technical solution: a core structure, the core structure comprising:

[0006] Core body;

[0007] The first busbar is located at the first end of the core body. The side of the first busbar away from the core body is provided with a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the first busbar, and the tab area is located in the outer ring area of ​​the first busbar and surrounds the tabless area.

[0008] The first electrode tab has one end fixedly connected to the core body, and the other end of the first electrode tab is fixed to the electrode tab area of ​​the first busbar by welding.

[0009] The first conductive sheet is fixedly connected to the tabless region of the first busbar.

[0010] In some alternative implementations, one end of the first tab is fixedly connected to the positive electrode plate of the core body, and the first conductive plate, the first tab, the first busbar and the positive electrode plate are made of the same material.

[0011] In some alternative embodiments, the thickness of the first conductive sheet is 0.5 mm to 1 mm, which is less than the thickness of the first tab.

[0012] In some alternative embodiments, the first conductive sheet and the first busbar are an integral structure; or,

[0013] The first conductive sheet and the first busbar are separate structures, and the first conductive sheet and the first busbar are fixed together by welding.

[0014] In some alternative implementations, the core structure further includes:

[0015] The second busbar is located at the second end of the core body. The side of the second busbar away from the core body is provided with a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the second busbar, and the tab area is located in the outer ring area of ​​the second busbar and surrounds the tabless area.

[0016] The second electrode ear has one end fixedly connected to the core body, and the other end fixedly welded to the electrode ear area of ​​the second busbar.

[0017] The second conductive sheet is fixedly connected to the tabless region of the second busbar.

[0018] In some alternative implementations, one end of the second tab is fixedly connected to the negative electrode of the core body, and the second conductive sheet, the second tab, the second busbar and the negative electrode are made of the same material.

[0019] In some alternative embodiments, the thickness of the second conductive sheet is 0.5 mm to 1 mm, which is less than the thickness of the second tab.

[0020] In some alternative embodiments, the second conductive sheet and the second busbar are an integral structure; or,

[0021] The second conductive sheet and the second busbar are separate structures, and the second conductive sheet and the second busbar are fixed together by welding.

[0022] In some alternative implementations, the core body is formed by winding together alternating layers of positive electrode sheet, negative electrode sheet and separator film.

[0023] In some optional embodiments, this application also provides a cylindrical battery, the cylindrical battery comprising:

[0024] The aforementioned core structure;

[0025] The battery casing has a core structure encapsulated inside, and the battery casing is filled with electrolyte.

[0026] In the aforementioned core structure, by setting a tabless region in the inner ring area of ​​the first busbar and fixing the first conductive sheet therein, the first conductive sheet and the first busbar form a parallel structure, reducing the internal resistance of the core structure and increasing its current transmission capacity. Furthermore, by increasing the thickness of the inner ring area with the first conductive sheet, the risk of the first busbar burning through and melting the insulating film of the core body can be effectively reduced when the welding area expands during the welding of the first tab. Thus, by fixing the first conductive sheet in the inner ring area of ​​the first busbar, both the internal resistance of the core structure can be reduced to improve current transmission capacity, and the risk of short circuits caused by the first busbar burning through and melting the insulating film can be effectively reduced when the welding area of ​​the first tab expands.

[0027] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0028] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0029] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0030] Figure 1 A cross-sectional structural schematic diagram of the core structure in an embodiment of this application is shown;

[0031] Figure 2 It shows Figure 1 A top view of the core structure;

[0032] Figure 3 It shows Figure 1 A schematic diagram of the core structure viewed from below;

[0033] Figure 4 The diagram shows a schematic cross-sectional view of the core structure of the cylindrical battery and the battery casing in an embodiment of this application.

[0034] Explanation of the labels in the diagram:

[0035] In the figure: 10, winding core structure; 11, winding core body; 12, first busbar; 13, first tab; 14, first conductive sheet; 15, second busbar; 16, second tab; 17, second conductive sheet; 20, battery casing. Detailed Implementation

[0036] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] In related technologies, the busbar is a key component for current collection. It is fixed to the tab by welding, and the welding area of ​​the tab on the busbar is concentrated in the outer ring area, while the inner ring area is a tabless area. However, due to the limited area of ​​the outer ring area, the welding area between the tab and the outer ring area of ​​the busbar is limited. If the welding area is expanded, it will cause the inner ring area to be welded through and melt the isolation film, which can easily cause a short circuit. In addition, when the current is transmitted from the tab to the busbar, the internal resistance of the busbar is large and the current transmission capability is poor.

[0040] To address these issues, researchers discovered that the inner ring area of ​​the busbar is a weak point with limited current carrying capacity. Furthermore, when the tabs are soldered to the outer ring area, the inner ring area is prone to burn-through. By adding and fixing conductive sheets to the inner ring area, the current carrying capacity of the inner ring area can be improved, and the risk of the busbar burning through can be reduced.

[0041] Therefore, combining Figure 1 and Figure 2In some embodiments, this application provides a core structure 10, which includes a core body 11, a first busbar 12, a first tab 13, and a first conductive sheet 14. The first busbar 12 is located at the first end of the core body 11. The side of the first busbar 12 facing away from the core body 11 is provided with a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the first busbar 12, and the tab area is located in the outer ring area of ​​the first busbar 12 and surrounds the tabless area. The first tab 13 has one end fixedly connected to the core body 11, and the other end of the first tab 13 is fixedly welded to the tab area of ​​the first busbar 12. The first conductive sheet 14 is fixedly connected to the tabless area of ​​the first busbar 12.

[0042] In the aforementioned core structure 10, by setting a tabless region in the inner ring area of ​​the first busbar 12 and fixing the first conductive sheet 14 thereon, the first conductive sheet 14 and the first busbar 12 form a parallel structure, reducing the internal resistance of the core structure 10 and increasing its current transmission capacity. Furthermore, by increasing the thickness of the inner ring area with the first conductive sheet 14, the risk of the first busbar 12 burning through and melting the insulating film of the core body 11 can be effectively reduced when the welding area of ​​the first tab 13 expands during welding. Thus, by fixing the first conductive sheet 14 in the inner ring area of ​​the first busbar 12, the internal resistance of the core structure 10 can be reduced to improve current transmission capacity, and the risk of short circuits caused by the first busbar 12 burning through and melting the insulating film can be effectively reduced when the welding area of ​​the first tab 13 expands.

[0043] In some embodiments, one end of the first tab 13 is fixedly connected to the positive electrode of the core body 11, and the first conductive sheet 14, the first tab 13, the first busbar 12 and the positive electrode are made of the same material.

[0044] In this way, using the same material can ensure the electrochemical compatibility of the components on the positive electrode side, reduce the risks of corrosion and interface reactions when different materials come into contact, and improve the long-term cycle stability of the battery. Moreover, the high conductivity matching of the same material can reduce contact resistance, make the current conduction on the positive electrode side smoother, and improve the battery charging and discharging efficiency.

[0045] In some alternative embodiments, the first conductive sheet 14, the first tab 13, the first busbar 12, and the positive electrode sheet can be made of aluminum or aluminum alloy (e.g., aluminum-manganese alloy).

[0046] In some preferred embodiments, the first tab 13 is fixed to the positive electrode by welding.

[0047] In some embodiments, the thickness of the first conductive sheet 14 is 0.5mm-1mm, and is less than or equal to the thickness of the first tab 13. Thus, when the thickness of the first conductive sheet 14 is less than 0.5mm, its mechanical and electrical properties are poor and cannot meet the requirements. When the thickness of the first conductive sheet 14 is greater than 1mm, the material usage increases, resulting in a heavier first conductive sheet 14. When the thickness of the first conductive sheet 14 is 0.5mm-1mm, a balance can be achieved between lightweight design and conductivity requirements, ensuring that the conductivity of the inner ring region meets the requirements. Furthermore, by designing the thickness of the first conductive sheet 14 to be less than the thickness of the first tab 13, volume redundancy caused by an excessively thick first conductive sheet 14 can be avoided, optimizing the space utilization of the inner ring region.

[0048] It should be noted that after the first tab 13 is fixed to the outer ring area of ​​the first busbar 12 by welding, the first tab 13 protrudes from the first busbar 12 in the outer ring area, so that the first busbar 12 automatically forms a hollow space in the inner ring area. The first conductive sheet 14 is fixed in the hollow space. When the thickness of the first conductive sheet 14 exceeds the thickness of the first tab 13, the first conductive sheet 14 will extend out of the hollow space, which will additionally increase the overall length of the core structure 10, thus resulting in volume redundancy.

[0049] Specifically, the first conductive sheet 14 can be a ring-shaped aluminum sheet.

[0050] In some optional embodiments, the first conductive sheet 14 and the first busbar 12 are an integral structure; thus, the integral structure can eliminate the connection interface, reduce contact resistance, improve structural stability, and is suitable for scenarios with high conductivity requirements.

[0051] In some alternative embodiments, the first conductive sheet 14 and the first busbar 12 are separate structures, and the first conductive sheet 14 and the first busbar 12 are fixed together by welding. In this way, the separate structure makes it easier to process the first conductive sheet and the first busbar 12 separately, improving the flexibility of production, and the welding fixation can ensure a reliable connection and meet the needs of mass production.

[0052] It should be noted that both of the above-mentioned connection structures between the first conductive sheet 14 and the first busbar 12 can ensure conductivity continuity and can be manufactured using different production processes.

[0053] Combination Figure 1 and Figure 3In some embodiments, the core structure 10 further includes a second busbar 15, a second tab 16, and a second conductive sheet 17. The second busbar 15 is located at the second end of the core body 11. The side of the second busbar 15 facing away from the core body 11 has a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the second busbar 15, and the tab area is located in the outer ring area of ​​the second busbar 15, surrounding the tabless area. The second tab 16 has one end fixedly connected to the core body 11, and the other end fixedly welded to the tab area of ​​the second busbar 15. The second conductive sheet 17 is fixedly connected to the tabless area of ​​the second busbar 15.

[0054] Thus, by setting a tabless area in the inner ring region of the second busbar 15 and fixing the second conductive sheet 17, the second conductive sheet 17 and the second busbar 15 form a parallel structure, reducing the internal resistance of the core structure 10 and increasing the current transmission capacity of the core structure 10. Furthermore, by increasing the thickness of the inner ring region by the second conductive sheet 17, when the welding area is expanded during the welding of the second tab 16, the risk of the second busbar 15 burning through and melting the insulating film of the core body 11 can be effectively reduced. Therefore, by fixing the second conductive sheet 17 in the inner ring region of the second busbar 15, the internal resistance of the core structure 10 can be reduced to improve the current transmission capacity, and the risk of short circuit caused by the second busbar 15 burning through and melting the insulating film can be effectively reduced when the welding area of ​​the second tab 16 expands.

[0055] In some embodiments, one end of the second tab 16 is fixedly connected to the negative electrode sheet of the core body 11, and the second conductive sheet 17, the second tab 16, the second busbar 15 and the negative electrode sheet are made of the same material.

[0056] In this way, using the same material can ensure the electrochemical compatibility of the components on the negative electrode side, reduce the risks of corrosion and interface reactions when different materials come into contact, and improve the long-term cycle stability of the battery. Moreover, the high conductivity matching of the same material can reduce contact resistance, make the current conduction on the positive electrode side smoother, and improve the battery charging and discharging efficiency.

[0057] In some alternative embodiments, the second conductive sheet 17, the second tab 16, the second busbar 15, and the negative electrode sheet can be made of aluminum or aluminum alloy (e.g., aluminum-manganese alloy).

[0058] In some preferred embodiments, the second electrode tab 16 is fixed to the negative electrode sheet by welding.

[0059] In some alternative embodiments, the second conductive sheet 17, the second tab 16, the second busbar 15, and the negative electrode sheet can be made of copper, copper alloy (e.g., copper-nickel alloy), or nickel.

[0060] In some embodiments, the thickness of the second conductive sheet 17 is 0.5 mm to 1 mm, which is less than the thickness of the second tab 16.

[0061] Thus, when the thickness of the second conductive sheet 17 is less than 0.5mm, its mechanical and electrical properties are poor and cannot meet the requirements. When the thickness of the second conductive sheet 17 is greater than 1mm, the amount of material used increases, resulting in a larger weight for the second conductive sheet 17. When the thickness of the second conductive sheet 17 is 0.5mm-1mm, a balance can be achieved between lightweight and conductivity requirements, ensuring that the conductivity of the inner ring area meets the requirements. In addition, by designing the thickness of the second conductive sheet 17 to be less than the thickness of the second tab 16, the volume redundancy caused by the excessive thickness of the second conductive sheet 17 can be avoided, and the space utilization of the inner ring area can be optimized.

[0062] It should be noted that after the second tab 16 is fixed to the outer ring area of ​​the second busbar 15 by welding, the second tab 16 protrudes from the second busbar 15 in the outer ring area, so that the second busbar 15 automatically forms a hollow space in the inner ring area. The second conductive sheet 17 is fixed in the hollow space. When the thickness of the second conductive sheet 17 exceeds the thickness of the second tab 16, the second conductive sheet 17 will extend out of the hollow space, which will additionally increase the overall length of the core structure 10, thus resulting in volume redundancy.

[0063] Specifically, the second conductive sheet 17 can be a ring-shaped copper sheet.

[0064] In some optional embodiments, the second conductive sheet 17 and the second busbar 15 are an integral structure; thus, the integral structure can eliminate the connection interface, reduce contact resistance, improve structural stability, and is suitable for scenarios with high conductivity requirements.

[0065] In some alternative embodiments, the second conductive sheet 17 and the second busbar 15 are separate structures, and the second conductive sheet 17 and the second busbar 15 are fixed together by welding.

[0066] Thus, the split structure facilitates the separate processing of the second conductor sheet and the second busbar 15, improving production flexibility, and the welding fixation ensures a reliable connection, meeting the needs of mass production.

[0067] It should be noted that both of the above-mentioned connection structures between the second conductive sheet 17 and the second busbar 15 can ensure conductivity continuity and can be manufactured using different production processes.

[0068] In some embodiments, the core body 11 is formed by winding together alternating positive electrode sheets, negative electrode sheets and separator films.

[0069] Thus, alternating stacking ensures that the positive and negative electrode sheets are in full contact with the electrolyte (increasing the reaction area), and the separator effectively prevents direct short circuit between the positive and negative electrodes, improving safety. Moreover, the winding process makes the structure compact and the volume utilization rate high, which can improve the energy density of the battery. At the same time, winding molding facilitates mass production and adapts to the cylindrical structure requirements of cylindrical batteries.

[0070] Combination Figure 4 In some embodiments, this application also provides a cylindrical battery, characterized in that the cylindrical battery includes the above-mentioned winding structure 10 and battery casing 20, the winding structure 10 is encapsulated in the battery casing 20, and the battery casing 20 is filled with electrolyte.

[0071] Thus, by integrating the advantages of the aforementioned core structure 10 (low internal resistance, high conductivity, structural stability, etc.), combined with the casing and electrolyte filling, the battery's sealing and electrochemical environment stability can be ensured. Moreover, it can improve the cycle life, charge and discharge rate, and safety of cylindrical batteries. At the same time, the optimized design of the core adapts to the space constraints of the cylindrical casing, improving the overall performance of the battery.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A core structure, characterized in that, The core structure includes: Core body; The first busbar is located at the first end of the core body. The first busbar has a tab area and a tabless area on the side away from the core body. The tabless area is located in the inner ring area of ​​the first busbar, and the tab area is located in the outer ring area of ​​the first busbar and surrounds the tabless area. The first electrode tab has one end fixedly connected to the core body, and the other end of the first electrode tab is fixed to the electrode tab area of ​​the first busbar by welding. The first conductive sheet is fixedly connected to the tabless region of the first busbar.

2. The core structure according to claim 1, characterized in that, One end of the first tab is fixedly connected to the positive electrode sheet of the core body, and the first conductive sheet, the first tab, the first busbar and the positive electrode sheet are made of the same material.

3. The core structure according to claim 1, characterized in that, The thickness of the first conductive sheet is 0.5mm-1mm, which is less than the thickness of the first tab.

4. The core structure according to claim 1, characterized in that, The first conductive sheet and the first busbar are an integral structure; or, The first conductive sheet and the first busbar are separate structures, and the first conductive sheet and the first busbar are fixed together by welding.

5. The core structure according to claim 1, characterized in that, The core structure also includes: The second busbar is located at the second end of the core body. The side of the second busbar away from the core body is provided with a tab area and a tabless area. The tabless area is located in the inner ring area of ​​the second busbar, and the tab area is located in the outer ring area of ​​the second busbar and surrounds the tabless area. The second electrode tab has one end fixedly connected to the core body, and the other end fixedly welded to the electrode area of ​​the second busbar. The second conductive sheet is fixedly connected to the tabless region of the second busbar.

6. The core structure according to claim 5, characterized in that, One end of the second tab is fixedly connected to the negative electrode sheet of the core body, and the second conductive sheet, the second tab, the second busbar are made of the same material as the negative electrode sheet.

7. The core structure according to claim 5, characterized in that, The thickness of the second conductive sheet is 0.5mm-1mm, which is less than the thickness of the second electrode tab.

8. The core structure according to claim 5, characterized in that, The second conductive sheet and the second busbar are an integral structure; or, The second conductive sheet and the second busbar are separate structures, and the second conductive sheet and the second busbar are fixed together by welding.

9. The core structure according to claim 1, characterized in that, The core body is formed by winding together alternating layers of positive electrode sheet, negative electrode sheet and separator film.

10. A cylindrical battery, characterized in that, The cylindrical battery includes: The core structure as described in any one of claims 1-9; A battery casing, wherein the core structure is encapsulated within the battery casing, and the battery casing is filled with electrolyte.

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