Core assembly with positive and negative terminals at the same end and cylindrical power battery

Abstract

This application discloses a wound core assembly with positive and negative electrodes at the same ends and a cylindrical power battery. The wound core assembly includes a wound core, a first positive current collector, a first negative current collector, a second positive current collector, and a second negative current collector. A first positive electrode tab region and a first negative electrode tab region are respectively provided on both sides of the first end of the wound core. A second positive electrode tab region, a second negative electrode tab region, a third positive electrode tab region, and a third negative electrode tab region are provided on the second end, and they are distributed sequentially and alternately along the circumference of the wound core. The first positive current collector is welded to the first positive electrode tab region, and the first negative current collector is welded to the first negative electrode tab region. The second positive current collector and the second negative current collector are alternately arranged, with the two ends of the second positive current collector welded to the second positive electrode tab region and the third positive electrode tab region, respectively, and the two ends of the second negative current collector welded to the second negative electrode tab region and the third negative electrode tab region, respectively. This application enables the insufficient overcurrent at the positive and negative electrodes at the first end of the wound core to be compensated at the second end.

Description

Technical Field

[0001] This application relates to the field of batteries, and more particularly to a wound core assembly with the positive and negative electrodes at the same ends and a cylindrical power battery. Background Technology

[0002] Currently, lithium-ion / sodium-ion cylindrical power batteries are gradually becoming the mainstream product in the new energy industry due to their advantages such as high energy density, good capacity consistency, and ability to support high-rate charging and discharging. With the popularization of new energy vehicles, people are placing increasingly higher demands on fast-charging travel (i.e., high-rate fast charging of power batteries). Current products have the following problems:

[0003] A few manufacturers have begun to install a positive and negative tab structure and positive and negative current collectors on one end of the cylindrical power battery core to avoid the battery being connected in series with the casing resistance. However, the other end of the core does not have a positive and negative tab structure and positive and negative current collectors, resulting in insufficient overcurrent at the positive and negative tabs on one end of the core. This leads to a larger internal resistance of the battery, making it difficult to achieve high-rate charging and discharging, and the temperature rise is also larger. Summary of the Invention

[0004] The purpose of this application is to provide a wound core assembly with positive and negative electrodes at the same ends and a cylindrical power battery, which can solve at least one of the technical problems mentioned in the background art.

[0005] To achieve the above objectives, this application provides a core assembly with positive and negative electrodes at the same end, comprising: a core having a first end and a second end opposite to the first end; a first positive electrode tab region and a first negative electrode tab region are respectively provided on both sides of the first end of the core; the second end of the core is provided with a second positive electrode tab region, a second negative electrode tab region, a third positive electrode tab region, and a third negative electrode tab region; the second positive electrode tab region, the second negative electrode tab region, the third positive electrode tab region, and the third negative electrode tab region are sequentially spaced along the circumference of the core; at least a portion of the second positive electrode tab region is located in the first positive electrode tab region projected onto the second end by the first positive electrode tab region; at least a portion of the second negative electrode tab region is located in the first negative electrode tab region projected onto the second end by the first negative electrode tab region. The third positive electrode region is not located in the projection region of the first positive electrode region, and at least a portion of the third positive electrode region is located in the projection region of the first negative electrode region. The third negative electrode region is not located in the projection region of the first negative electrode region, and at least a portion of the third negative electrode region is located in the projection region of the first positive electrode region. A first positive electrode current collector and a first negative electrode current collector are provided, with the first positive electrode current collector welded to the first positive electrode region and the first negative electrode current collector welded to the first negative electrode region. A second positive electrode current collector and a second negative electrode current collector are provided, with the second positive electrode current collector and the second negative electrode current collector being staggered and spaced apart. The two ends of the second positive electrode current collector are respectively welded to the second positive electrode region and the third positive electrode region, and the two ends of the second negative electrode current collector are respectively welded to the second negative electrode region and the third negative electrode region.

[0006] Optionally, the first end of the winding core is divided into two half-regions by one of its diameters, and this diameter is defined as the first diameter. The first positive tab region is located in the first half-region of the first end, and the first negative tab region is located in the second half-region of the first end.

[0007] Optionally, the second end of the core is divided into two halves by the first diameter of the core. The second positive tab region and the third negative tab region are located in the first half of the second end, and the second negative tab region and the third positive tab region are located in the second half of the second end. The first half of the second end is opposite to the first half of the first end, and the second half of the second end is opposite to the second half of the first end.

[0008] Optionally, the second positive electrode region is completely located within the first positive electrode projection region, and the second negative electrode region is completely located within the first negative electrode projection region.

[0009] Optionally, the area of ​​the third positive electrode tab region is larger than the area of ​​the second positive electrode tab region, and the second positive electrode current collector includes a first solder area welded to the second positive electrode tab region and a second solder area welded to the third positive electrode tab region, the area of ​​the second solder area being larger than the area of ​​the first solder area; the area of ​​the third negative electrode tab region is larger than the area of ​​the second negative electrode tab region, and the second negative electrode current collector includes a third solder area welded to the second negative electrode tab region and a fourth solder area welded to the third negative electrode tab region, the area of ​​the fourth solder area being larger than the area of ​​the third solder area.

[0010] Optionally, the first positive electrode current collector includes an outwardly extending positive electrode extension portion, the positive electrode extension portion having a through hole, the positive electrode extension portion being configured to be bent upward and welded to the bottom surface of the electrode post on the top cover, and the through hole being configured to correspond to the liquid injection hole on the electrode post.

[0011] Optionally, the outer side of the first negative electrode current collector is provided with an upwardly bent negative electrode extension, which is used for welding to the side wall of the housing.

[0012] Optionally, the first positive current collector and the first negative current collector are connected together at intervals through a first insulator.

[0013] Optionally, the second positive current collector and the second negative current collector are connected together at intervals through a second insulator.

[0014] To achieve the above objectives, this application also provides a cylindrical power battery, including a housing, a top cover, and a core assembly with positive and negative electrodes at the same end as described above; the top cover is disposed over an opening at one end of the housing; the core assembly is disposed inside the housing.

[0015] This application achieves this by providing a second positive electrode lug region, a second negative electrode lug region, a third positive electrode lug region, and a third negative electrode lug region that are circumferentially spaced at the second end of the core at the same positive and negative electrode ends (first end), and by using staggered second positive electrode current collectors and second negative electrode current collectors to respectively connect (bridge) the second positive electrode lug region and the third positive electrode lug region, as well as the second negative electrode lug region and the third negative electrode lug region. This allows the insufficient overcurrent at the positive and negative electrode lugs at the first end of the core to be compensated at the second end (at least partially located in the projection area of ​​the first negative electrode lug region and at least partially located in the projection area of ​​the first positive electrode lug region). The bridging of the second positive tab region of the domain can supplement the absence of the first positive tab region on the other half of the first end. The bridging of the third negative tab region, which is at least partially located in the projection area of ​​the first positive tab, and the second negative tab region, which is at least partially located in the projection area of ​​the first negative tab, can supplement the absence of the first negative tab region on the other half of the first end. Thus, this application can effectively solve the problem of high internal resistance of cylindrical power batteries caused by the same positive and negative terminals by supplementing the second end, while avoiding the introduction of casing resistance. This can improve the high-rate charge and discharge performance and charge and discharge temperature rise of cylindrical power batteries. Attached Figure Description

[0016] Figure 1 This is an exploded structural diagram of the core assembly according to an embodiment of this application.

[0017] Figure 2 This is another exploded structural diagram of the core assembly in an embodiment of this application.

[0018] Figure 3 This is a three-dimensional structural schematic diagram of the first positive current collector, the first negative current collector, and the first insulator according to an embodiment of this application.

[0019] Figure 4 This is a three-dimensional structural schematic diagram of the second positive current collector, the second negative current collector, and the second insulator in an embodiment of this application.

[0020] Figure 5 This is a top view (viewed from the first end located at the top) of the core assembly in the embodiment of this application.

[0021] Figure 6 This is a bottom view (viewed from the second end at the bottom) of the core assembly in the embodiment of this application.

[0022] Figure 7 This is a top perspective view of the core in the core assembly of the present application embodiment.

[0023] Figure 8 This is a three-dimensional structural diagram of the cylindrical power battery according to an embodiment of this application.

[0024] Figure 9This is an exploded structural diagram of the cylindrical power battery according to an embodiment of this application.

[0025] Figure 10 yes Figure 8 A cross-sectional view along line AA in the middle. Detailed Implementation

[0026] To explain in detail the technical content, structural features, objectives and effects of this application, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0027] Please see Figures 1 to 7 This application discloses a core assembly with positive and negative electrodes at the same end, including a core 1, a first positive current collector 2 and a first negative current collector 3, a second positive current collector 5 and a second negative current collector 6. The core 1 has a first end and a second end opposite to the first end. A first positive electrode tab region 11 and a first negative electrode tab region 12 are respectively provided on both sides of the first end of the core 1. The second end of the core 1 has a second positive electrode tab region 13, a second negative electrode tab region 15, a third positive electrode tab region 14, and a third negative electrode tab region 16. These regions are distributed sequentially and at intervals along the circumference of the core 1. At least a portion of the second positive electrode tab region 13 is located within the projection area of ​​the first positive electrode tab region 11 projected onto the second end. At least a portion of the second negative electrode tab region 15 is located within the projection area of ​​the first negative electrode tab region 12 projected onto the second end. The third positive electrode tab region 14 is not located within the projection area of ​​the first positive electrode tab region 11 projected onto the second end. A positive electrode projection area, at least a portion of the third positive electrode projection area 14 is located in the first negative electrode projection area, the third negative electrode projection area 16 is not located in the first negative electrode projection area, and at least a portion of the third negative electrode projection area 16 is located in the first positive electrode projection area; a first positive electrode current collector 2 and a first negative electrode current collector 3, the first positive electrode current collector 2 is welded to the first positive electrode projection area 11, and the first negative electrode current collector 3 is welded to the first negative electrode projection area 12; a second positive electrode current collector 5 and a second negative electrode current collector 6, the second positive electrode current collector 5 and the second negative electrode current collector 6 are alternately arranged, the two ends of the second positive electrode current collector 5 are respectively welded to the second positive electrode projection area 13 and the third positive electrode projection area 14, and the two ends of the second negative electrode current collector 6 are respectively welded to the second negative electrode projection area 15 and the third negative electrode projection area 16.

[0028] This application provides a second positive electrode tab region 13, a second negative electrode tab region 15, a third positive electrode tab region 14, and a third negative electrode tab region 16 arranged circumferentially at intervals at the second end of the core 1 at the same positive and negative electrode ends (first end). It also utilizes a second positive electrode current collector 5 and a second negative electrode current collector 6 arranged in an alternating manner to respectively connect (bridge) the second positive electrode tab region 13 and the third positive electrode tab region 14, as well as the second negative electrode tab region 15 and the third negative electrode tab region 16. This allows insufficient overcurrent at the positive and negative electrode tabs at the first end of the core 1 to be compensated at the second end (at least partially located in the projection area of ​​the first negative electrode tab, the third positive electrode tab region 14 and at least partially located in the projection area of ​​the first negative electrode tab are connected). The bridging of the second positive tab region 13 in the positive tab projection area can compensate for the absence of the first positive tab region 11 on the other half of the first end. The bridging of the third negative tab region 16, which is at least partially located in the first positive tab projection area, and the second negative tab region 15, which is at least partially located in the first negative tab projection area, can compensate for the absence of the first negative tab region 12 on the other half of the first end. Thus, this application can effectively solve the problem of high internal resistance of cylindrical power batteries caused by the same positive and negative terminals by supplementing the second end, while avoiding the introduction of casing resistance. This can improve the high-rate charge and discharge performance and charge and discharge temperature rise of cylindrical power batteries.

[0029] In a specific example, the first positive electrode region 11 is axially symmetrically arranged, and its centerline is the first centerline. The first negative electrode region 12 is also axially symmetrically arranged, and its centerline is the second centerline. The first centerline passes through the third positive electrode region 14, and the second centerline passes through the third negative electrode region 16. The first centerline and the second centerline are straight lines with the same diameter.

[0030] In some embodiments, the first end of the core 1 is divided into two half-regions by one of the diameters of the core 1, and the diameter is defined as the first diameter. The first positive tab region 11 is located in the first half-region 17 of the first end, and the first negative tab region 12 is located in the second half-region 18 of the first end.

[0031] Furthermore, the second end of the core 1 is divided into two halves by the first diameter of the core 1. The second positive tab region 13 and the third negative tab region 16 are located in the first half 19 of the second end, and the second negative tab region 15 and the third positive tab region 14 are located in the second half 20 of the second end. The first half 19 of the second end is directly opposite the first half 17 of the first end, and the second half 20 of the second end is directly opposite the second half 18 of the first end.

[0032] Specifically, the second positive electrode region 13 is completely located within the projection region of the first positive electrode, and the second negative electrode region 15 is completely located within the projection region of the first negative electrode. The second positive electrode region 13, which is completely located within the projection region of the first positive electrode, is beneficial for providing overcurrent compensation to the first positive electrode region 11, and the second negative electrode region 15, which is completely located within the projection region of the first negative electrode, is beneficial for providing overcurrent compensation to the first negative electrode region 12.

[0033] Specifically, the area of ​​the third positive tab region 14 is larger than the area of ​​the second positive tab region 13. The second positive current collector 5 includes a first solder area 51 welded to the second positive tab region 13 and a second solder area 52 welded to the third positive tab region 14, with the area of ​​the second solder area 52 being larger than the area of ​​the first solder area 51. The area of ​​the third negative tab region 16 is larger than the area of ​​the second negative tab region 15. The second negative current collector 6 includes a third solder area 61 welded to the second negative tab region 15 and a fourth solder area 62 welded to the third negative tab region 16, with the area of ​​the fourth solder area 62 being larger than the area of ​​the third solder area 61. Because the area of ​​the third positive tab region 14 is larger than the area of ​​the second positive tab region 13 and the area of ​​the second solder area 52 of the second positive current collector 5 is larger than the area of ​​the first solder area 51, it is advantageous for the third positive tab region 14 and the second solder area 52 to supplement the overcurrent on the other side of the first positive tab region 11 with a larger area. Since the area of ​​the third negative electrode tab region 16 is larger than the area of ​​the second negative electrode tab region 15 and the area of ​​the fourth solder area 62 of the second negative electrode current collector 6 is larger than the area of ​​the third solder area 61, it is beneficial for the third negative electrode tab region 16 and the fourth solder area 62 to supplement the overcurrent on the other side of the first negative electrode tab region 12 with a larger area.

[0034] Specifically, the first positive electrode current collector 2 includes an outwardly extending positive electrode extension 21. The positive electrode extension 21 is provided with a through hole 22. The positive electrode extension 21 is configured to be bent upward and welded to the bottom surface of the electrode post 101 on the top cover 10. The through hole 22 is configured to correspond to the liquid injection hole 102 on the electrode post 101 and to the center hole 9 of the core 1.

[0035] Of course, this application is not limited to the positive electrode extension 21 being directly welded to the electrode post 101. For example, when the top cover 10 and the electrode post 101 are integrated, the positive electrode extension 21 can also be directly welded to the top cover 10.

[0036] Specifically, the outer side of the first negative electrode current collector 3 is provided with an upwardly bent negative electrode extension 31, which is used for welding to the side wall of the housing 111. Of course, the first negative electrode current collector 3 is not limited to being welded to the housing 111. In some other embodiments, the first negative electrode current collector 3 can also be welded to the top cover 10, in which case the electrode post 101 is insulated from the top cover 10.

[0037] Furthermore, at least one stress relief notch 32 is provided on the upwardly bent negative electrode extension 31. The notch 32 can release impact stress, avoid the risk of open circuit at the welding position of the negative electrode extension 31 and the side wall of the casing 111, and improve the shock resistance of the cylindrical power battery.

[0038] In some embodiments, the first positive current collector 2 and the first negative current collector 3 are connected to each other at intervals by the first insulator 4, which facilitates integrated assembly, makes it easy to determine the relative positions of the first positive current collector 2 and the first negative current collector 3, and prevents short circuits caused by the connection of the first positive current collector 2 and the first negative current collector 3.

[0039] Specifically, the first insulator 4 is provided with a liquid injection through hole 40 corresponding to the liquid injection hole 102 on the pole post 101 to avoid blocking the liquid injection.

[0040] Specifically, the first insulator 4 is provided with multiple through holes 41, which can better allow electrolyte to seep in, reduce the amount of raw materials used, and thus reduce the weight of the battery.

[0041] Specifically, the first insulator 41 is used to connect the first positive current collector 2 and the first negative current collector 3 together in an alternating manner through injection molding. Of course, the first insulator 41 can also connect the first positive current collector 2 and the first negative current collector 3 together in an alternating manner through other means, such as assembly connection, etc., which are not limited here.

[0042] It should be noted that more than one first insulator 41 can be set, or two, three, etc., as long as they are mutually spaced and insulated from each other, and the first positive current collector 2 and the first negative current collector 3 are connected.

[0043] In some embodiments, the second positive current collector 5 and the second negative current collector 6 are connected together at intervals by a second insulator 7. The second negative current collector 6 spans across the second positive current collector 5 and is staggered with the second positive current collector 5. The second insulator 7 is provided in the intermediate region between the two to connect the second positive current collector 5 and the second negative current collector 6 together at intervals. Since the second positive current collector 5 and the second negative current collector 6 are connected together at intervals by the second insulator 7, it is convenient to perform integral assembly, and it is easy to determine the relative positions of the second positive current collector 5 and the second negative current collector 6. At the same time, it can prevent the second positive current collector 5 and the second negative current collector 6 from being connected and causing a short circuit.

[0044] Specifically, the second insulator 7 is used to integrally connect the second positive current collector 5 and the second negative current collector 6 with each other at intervals by injection molding. Of course, the second insulator 7 can also integrally connect the second positive current collector 5 and the second negative current collector 6 with each other at intervals by other means, such as assembly connection, etc., which is not limited here.

[0045] It should be noted that more than one second insulator 7 can be set, or two, three, etc., as long as they are mutually spaced and insulated from each other, and connected to the second positive current collector 5 and the second negative current collector 6.

[0046] In some embodiments, the first positive tab region 11, the second positive tab region 13, and the third positive tab region 14 are aluminum foil, and the first negative tab region 12, the second negative tab region 15, and the third negative tab region 16 are copper foil. Of course, this is not a limitation.

[0047] Please see Figures 8 to 10 This application also discloses a cylindrical power battery, including a housing 111, a top cover 10, and a core assembly with positive and negative electrodes at the same end as described above; the top cover 10 is disposed over an opening at one end of the housing 111; the core assembly is disposed inside the housing 111.

[0048] This application provides a second positive electrode tab region 13, a second negative electrode tab region 15, a third positive electrode tab region 14, and a third negative electrode tab region 16 arranged circumferentially at intervals at the second end of the core 1 at the same positive and negative electrode ends (first end). It also utilizes a second positive electrode current collector 5 and a second negative electrode current collector 6 arranged in an alternating manner to respectively connect (bridge) the second positive electrode tab region 13 and the third positive electrode tab region 14, as well as the second negative electrode tab region 15 and the third negative electrode tab region 16. This allows insufficient overcurrent at the positive and negative electrode tabs at the first end of the core 1 to be compensated at the second end (at least partially located in the projection area of ​​the first negative electrode tab, the third positive electrode tab region 14 and at least partially located in the projection area of ​​the first negative electrode tab are connected). The bridging of the second positive tab region 13 in the positive tab projection area can compensate for the absence of the first positive tab region 11 on the other half of the first end. The bridging of the third negative tab region 16, which is at least partially located in the first positive tab projection area, and the second negative tab region 15, which is at least partially located in the first negative tab projection area, can compensate for the absence of the first negative tab region 12 on the other half of the first end. Thus, this application can effectively solve the problem of high internal resistance of cylindrical power batteries caused by the same positive and negative terminals by supplementing the second end, while avoiding the introduction of casing resistance. This can improve the high-rate charge and discharge performance and charge and discharge temperature rise of cylindrical power batteries.

[0049] The above-disclosed examples are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the scope of this application shall still fall within the scope of this application.

Claims

1. A winding core assembly with positive and negative electrodes at the same ends, characterized in that, include: A core having a first end and a second end opposite to the first end; a first positive tab region and a first negative tab region are respectively provided on both sides of the first end of the core; the second end of the core is provided with a second positive tab region, a second negative tab region, a third positive tab region, and a third negative tab region; the second positive tab region, the second negative tab region, the third positive tab region, and the third negative tab region are sequentially spaced along the circumference of the core; at least a portion of the second positive tab region is located in the first positive tab projection region of the first positive tab region projected onto the second end; at least a portion of the second negative tab region is located in the first negative tab projection region of the first negative tab region projected onto the second end; the third positive tab region is not located in the first positive tab projection region, but at least a portion of the third positive tab region is located in the first negative tab projection region; the third negative tab region is not located in the first negative tab projection region, but at least a portion of the third negative tab region is located in the first positive tab projection region. A first positive current collector and a first negative current collector, wherein the first positive current collector is welded to the first positive tab region and the first negative current collector is welded to the first negative tab region; The second positive current collector and the second negative current collector are arranged alternately. The two ends of the second positive current collector are respectively welded to the second positive tab region and the third positive tab region, and the two ends of the second negative current collector are respectively welded to the second negative tab region and the third negative tab region.

2. The winding core assembly with the positive and negative electrodes at the same ends according to claim 1, characterized in that, The first end of the winding core is divided into two half-regions by one of its diameters, and this diameter is defined as the first diameter. The first positive tab region is located in the first half-region of the first end, and the first negative tab region is located in the second half-region of the first end.

3. The winding core assembly with the positive and negative electrodes at the same ends according to claim 2, characterized in that, The second end of the core is divided into two halves by the first diameter of the core. The second positive tab region and the third negative tab region are located in the first half of the second end, and the second negative tab region and the third positive tab region are located in the second half of the second end. The first half of the second end is directly opposite the first half of the first end, and the second half of the second end is directly opposite the second half of the first end.

4. The winding core assembly with the positive and negative electrodes at the same ends according to any one of claims 1 to 3, characterized in that, The second positive electrode region is completely located within the projection region of the first positive electrode region, and the second negative electrode region is completely located within the projection region of the first negative electrode region.

5. The winding core assembly with the positive and negative electrodes at the same ends according to any one of claims 1 to 3, characterized in that, The area of ​​the third positive electrode tab region is larger than the area of ​​the second positive electrode tab region. The second positive electrode current collector includes a first solder area welded to the second positive electrode tab region and a second solder area welded to the third positive electrode tab region, and the area of ​​the second solder area is larger than the area of ​​the first solder area. The area of ​​the third negative electrode tab region is larger than the area of ​​the second negative electrode tab region. The second negative electrode current collector includes a third solder area welded to the second negative electrode tab region and a fourth solder area welded to the third negative electrode tab region, and the area of ​​the fourth solder area is larger than the area of ​​the third solder area.

6. The winding core assembly with the positive and negative electrodes at the same ends according to claim 1, characterized in that, The first positive electrode current collector includes an outwardly extending positive electrode extension portion, which has a through hole. The positive electrode extension portion is configured to be bent upward and welded to the bottom surface of the electrode post on the top cover. The through hole is configured to correspond to the liquid injection hole on the electrode post.

7. The winding core assembly with the positive and negative electrodes at the same ends according to claim 1, characterized in that, The outer side of the first negative electrode current collector is provided with an upwardly bent negative electrode extension, which is used for welding to the side wall of the housing.

8. The winding core assembly with the positive and negative electrodes at the same ends according to claim 1, characterized in that, The first positive current collector and the first negative current collector are connected together at intervals through a first insulator.

9. The winding core assembly with the positive and negative electrodes at the same ends according to claim 1, characterized in that, The second positive current collector and the second negative current collector are connected together at intervals through a second insulator.

10. A cylindrical power battery, characterized in that, include: case; A top cover, which is disposed over an opening at one end of the housing; The core assembly with the same positive and negative terminals as described in any one of claims 1 to 9, wherein the core assembly is disposed inside the housing.

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