Roll core and battery cell

Abstract

The utility model provides a roll core and a battery cell, and the roll core comprises a winding body which comprises a positive plate, a diaphragm and a negative plate which are sequentially laminated and wound; the tab group is arranged at the axial end part of the winding body, the tab group comprises a plurality of tabs, the plurality of tabs are respectively connected to different winding ring layers of the same pole piece and are mutually aligned, the axial direction of the winding body is the height direction of the tabs, and the heights of the plurality of tabs are gradually reduced along the alignment direction of the plurality of tabs. According to the invention, the plurality of tabs connected to the different winding ring layers of the pole piece are aligned with each other, and the heights of the tabs are gradually reduced along the alignment direction of the tabs, so that the plurality of tabs can be overlapped together to be welded on the same connecting piece during welding, the welding of the plurality of tabs can be completed at one time, and the workload of welding the tabs can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a winding core and a battery cell. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, good cycle performance, wide operating temperature range, no memory effect, low self-discharge, and high safety. With the diversification of the times, the application range of lithium-ion batteries continues to expand and has rapidly developed into a new generation of energy storage, used for power support in fields such as information technology, electric vehicles, hybrid vehicles, and aerospace.

[0003] The current process of welding the tabs of lithium-ion batteries is labor-intensive and has a high rate of misalignment defects. In order to pursue higher rate and cycle performance, the heat generation of lithium-ion batteries increases, which leads to a significant decrease in battery cycle life and safety performance. At the same time, the overall heat dissipation cost increases after the cells are assembled into modules or packs. Utility Model Content

[0004] The embodiments of this utility model provide a core and a battery cell, which can improve the technical problem of the large workload of welding electrode tabs in existing technologies.

[0005] In a first aspect, embodiments of the present invention provide a winding core, comprising:

[0006] The wound body includes a positive electrode sheet, a separator, and a negative electrode sheet that are sequentially stacked and wound together;

[0007] A tab assembly is disposed at the axial end of the wound body. The tab assembly includes multiple tabs, which are respectively connected to different winding layers of the same electrode sheet and are aligned with each other in a direction parallel to the axial end. The axial direction of the wound body is the height direction of the tabs, and the height of the multiple tabs gradually decreases along the alignment direction of the multiple tabs.

[0008] In embodiments of this utility model, by aligning multiple tabs connected to different winding layers of the electrode sheet with each other and gradually decreasing their height along the alignment direction, multiple tabs can be overlapped and welded onto the same connecting piece during welding, thereby achieving the welding of multiple tabs at one time and reducing the workload of tab welding.

[0009] In one embodiment, the electrode group includes a first electrode group and a second electrode group, the first electrode group and the second electrode group are located at the same axial end of the winding body, respectively disposed on both sides of the winding axis of the winding body, and are aligned with each other.

[0010] In embodiments of this invention, by aligning the first and second electrode groups and gradually decreasing their height, the ends of the first and second electrode groups that are overlapping during welding are flush with the ends away from the electrode sheet, allowing them to be welded onto the same connecting piece. This facilitates welding and prevents incomplete welding. In one embodiment, the number of electrodes in the first electrode group is the same as the number of winding layers of the electrode sheet, and the alignment direction of the plurality of electrodes is from the second electrode group towards the first electrode group.

[0011] In the embodiments of this utility model, by making the number of tabs in the first tab group the same as the number of winding layers of the electrode sheet, the basic requirements of the battery can be met. By setting a second tab group, the number of tabs can be increased, thereby increasing the tab current-carrying area, reducing the DCR and heat generation of a single cell, thereby increasing the cell cycle life and reducing the heat dissipation cost of the module or PACK.

[0012] In one embodiment, the winding direction of the winding body is the width direction of the tabs, and the width of the multiple tabs gradually decreases along the direction in which the multiple tabs are aligned.

[0013] In embodiments of this invention, by gradually reducing the width of the tabs distributed along the tab alignment direction, the tab misalignment defect rate can be reduced, and incomplete soldering can be avoided.

[0014] In one embodiment, the width of the plurality of tabs gradually decreases along the direction away from the winding body.

[0015] In embodiments of this invention, by gradually reducing the width of the tab along the direction away from the winding body, it is possible to prevent the tab from folding along its height direction during the winding process.

[0016] In one embodiment, the side of the tab opposite to the electrode sheet is arc-shaped; or,

[0017] The two ends of the tab on the side away from the electrode plate are chamfered.

[0018] In embodiments of this utility model, by making the side of the tab away from the electrode sheet arc-shaped or setting chamfers at both ends, it is possible to prevent the side of the tab away from the electrode sheet from folding during the winding process.

[0019] In one embodiment, the tab group is a first polarity tab group, and the winding core further includes a second polarity tab group. The second polarity tab group and the first polarity tab group are respectively disposed at both ends of the same axial end of the winding body. One of the first polarity tab group and the second polarity tab group is a positive tab group, and the other is a negative tab group.

[0020] In the embodiments of this utility model, by setting the positive electrode lug and the negative electrode lug at both ends of the axial end of the winding body, the safety risks caused by the overlap of the positive electrode lug and the negative electrode lug can be prevented, and it is also convenient to perform welding operations on the positive electrode lug and the negative electrode lug separately.

[0021] In one embodiment, the first polarity tab group is a positive tab group, and the second polarity tab group is a negative tab group, including multiple negative tabs. The multiple negative tabs are respectively connected to different winding layers of the negative electrode sheet and are aligned with each other. Along the alignment direction of the multiple negative tabs, the height of the multiple negative tabs gradually decreases.

[0022] In embodiments of this utility model, by aligning the positive and negative tabs with each other and gradually decreasing their height along their respective alignment directions, the positive tabs can be overlapped and welded onto the same connecting piece during welding, and the negative tabs can be overlapped and welded onto the same connecting piece during welding, thereby reducing the workload of tab welding.

[0023] Secondly, embodiments of this utility model provide a battery cell, comprising:

[0024] Connecting piece;

[0025] In the aforementioned core, the tabs in the tab assembly overlap at the end opposite to the electrode sheet and are welded to the same side of the connecting piece.

[0026] In an embodiment of this utility model, by overlapping the end of the electrode tab in the electrode tab assembly that is away from the electrode sheet with the same side of the connecting piece, the welding of all the electrode tabs in the electrode tab assembly can be completed at one time, which can reduce the amount of welding work.

[0027] In one embodiment, the battery cell includes at least two winding cores, the tabs of the at least two winding cores are aligned, and the connecting piece is welded to the tabs of two adjacent winding cores.

[0028] In embodiments of this utility model, by providing a U-shaped connecting piece between every two adjacent cores to connect the two cores on both sides, the number of connecting pieces can be reduced, making integration easier. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the winding core provided in an embodiment of this utility model;

[0031] Figure 2 This is a schematic diagram of a type of electrode tab provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a type of electrode tab provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of a type of electrode tab provided in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the welding of the battery cell provided in an embodiment of this utility model;

[0035] Figure 6 yes Figure 5 A bottom view. Attached image description:

[0037] Winding body-1; Positive electrode plate-11; Separator-12; Negative electrode plate-13; Positive electrode tab group-2; First electrode tab group-3; Second electrode tab group-4; Negative electrode tab group-5; Arc-shaped-6; Chamfer-7; Connecting piece-8; Positive electrode connecting piece-81; Negative electrode connecting piece-82. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0039] Please see Figure 1-4 In a first aspect, embodiments of the present invention provide a winding core, comprising:

[0040] The wound body 1 includes a positive electrode 11, a separator 12 and a negative electrode 13 that are stacked and wound in sequence;

[0041] A tab assembly is disposed at the axial end of the winding body 1. The tab assembly includes multiple tabs, which are respectively connected to different winding layers of the same electrode sheet and are aligned with each other in a direction parallel to the axial end. The axial direction of the winding body 1 is the height direction of the tabs, and the height of the multiple tabs gradually decreases along the alignment direction of the multiple tabs.

[0042] It is understandable that the cross-section of the coil 1 can be circular, elliptical, or a combination of straight lines and arcs.

[0043] Multiple tabs in the tab group are connected to different winding layers of the same electrode sheet, meaning the tabs in the tab group are of the same polarity. In this application, the tab group can be either a positive tab group 2 or a negative tab group 5. The tabs in the positive tab group 2 are positive tabs and are connected to the positive electrode sheet 11, while the tabs in the negative tab group 5 are negative tabs and are connected to the negative electrode sheet 13. The positive tab group 2 and the negative tab group 5 are two independent tab groups of different polarities, and their alignment direction and height are independent of each other.

[0044] The height of the tab refers to its dimension along the axial direction of the winding body 1. The width of the tab refers to its dimension along the winding direction of the winding body 1.

[0045] The multiple electrodes of the electrode assembly are aligned with each other, meaning that the multiple electrodes are coplanar along their central axes in the height direction. For example, the height of multiple tabs gradually decreases. This can be done by gradually decreasing according to a fixed value or by gradually decreasing according to a non-fixed value. It can be done by gradually decreasing two adjacent tabs or by gradually decreasing in groups. For example, along the direction in which multiple tabs are aligned, the first 10% of the tabs extend outward from the axial end of the winding body 1 at a consistent height; the 10% to 30% of the tabs extend outward from the axial end of the winding body 1 at a consistent height, and are smaller than the first 10% of the tabs; the 30% to 50% of the tabs extend outward from the axial end of the winding body 1 at a consistent height, and are smaller than the 10% to 30% of the tabs; the 50% to 80% of the tabs extend outward from the axial end of the winding body 1 at a consistent height, and are smaller than the 30% to 50% of the tabs; the 80% to 100% of the tabs extend outward from the axial end of the winding body 1 at a consistent height, and are smaller than the 50% to 80% of the tabs.

[0046] In one embodiment, the electrode group includes a first electrode group 3 and a second electrode group 4. The first electrode group 3 and the second electrode group 4 are located at the same axial end of the winding body 1, respectively disposed on both sides of the winding axis of the winding body 1, and are aligned with each other.

[0047] It can be understood that the first electrode group 3 and the second electrode group 4 are aligned with each other, meaning that the central axis of the electrode in the height direction of the first electrode group 3 and the central axis of the electrode in the height direction of the second electrode group 4 are coplanar.

[0048] In one embodiment, the number of electrodes in the first electrode group 3 is the same as the number of winding layers of the electrode sheet, and the direction in which the plurality of electrodes are aligned is from the second electrode group 4 to the first electrode group 3.

[0049] It is understandable that the number of tabs in the second tab group 4 can be adjusted as needed, thereby adjusting the tab current-passing area to adapt to the battery requirements of different rates.

[0050] In one embodiment, the winding direction of the winding body 1 is the width direction of the tabs, and the width of the multiple tabs gradually decreases along the direction in which the multiple tabs are aligned.

[0051] It is understandable that the width of the tabs extending along the winding direction of the winding body 1 gradually decreases. This can be a gradual decrease based on a fixed value or a gradual decrease based on a non-fixed value. It can be a gradual decrease for two adjacent tabs or a gradual decrease for groups. For example, along the direction of tab alignment, the width of the first 10% of the tabs extending along the winding direction of the winding body 1 is consistent; the width of the 10% to 30% of the tabs extending along the winding direction of the winding body 1 is consistent and smaller than that of the first 10% of the tabs; the width of the 30% to 50% of the tabs extending along the winding direction of the winding body 1 is consistent and smaller than that of the 10% to 30% of the tabs; the width of the 50% to 80% of the tabs extending along the winding direction of the winding body 1 is consistent and smaller than that of the 30% to 50% of the tabs; and the width of the 80% to 100% of the tabs extending along the winding direction of the winding body 1 is consistent and smaller than that of the 50% to 80% of the tabs.

[0052] In one embodiment, the width of the plurality of tabs gradually decreases in the direction away from the winding body 1.

[0053] It is understood that the electrode lugs can be trapezoidal in shape, and the inclination of the two sides can be set as needed. In one embodiment, the electrode lugs are isosceles trapezoidal in shape.

[0054] Please see Figure 2 In one embodiment, the side of the tab opposite to the electrode sheet is arc-shaped. It can be understood that the curvature of the arc 6 can be set as needed.

[0055] Please see Figure 3-4 In one embodiment, the two ends of the tab on the side away from the electrode sheet are chamfered.

[0056] It is understandable that chamfer 7 can be a rounded corner or a triangular notch, and the size and shape of the triangular notch can be set as needed.

[0057] In one embodiment, the tab group is a first polarity tab group, and the winding core further includes a second polarity tab group. The second polarity tab group and the first polarity tab group are respectively disposed at both ends of the same axial end of the winding body 1. One of the first polarity tab group and the second polarity tab group is a positive tab group, and the other is a negative tab group 5.

[0058] In one embodiment, the first polarity tab group is a positive tab group 2, and the second polarity tab group is a negative tab group 5, which includes multiple negative tabs. The multiple negative tabs are respectively connected to different winding layers of the negative electrode sheet and are aligned with each other. Along the alignment direction of the multiple negative tabs, the height of the multiple negative tabs gradually decreases.

[0059] It is understood that the tab group in this application is the positive tab group 2, and the tabs in the positive tab group 2 are the positive tabs, connected to the positive electrode plate 11. The tabs in the negative tab group 5 are the negative tabs, connected to the negative electrode plate 13. The negative tabs of the negative tab group 5 can also meet the height, width, structure, and other characteristics of the tabs in the tab group (for details, please refer to the description of the tab group above). For the sake of brevity, it will not be elaborated here.

[0060] Please see Figure 1-6 Secondly, embodiments of this utility model provide a battery cell, comprising:

[0061] Connecting piece 8;

[0062] In the aforementioned core, the tabs in the tab assembly overlap at the end opposite to the electrode sheet and are welded to the same side of the connecting piece 8.

[0063] It is understood that the tab assembly can be either the positive tab assembly 2 or the negative tab assembly 5. Correspondingly, the connecting piece 8 can be either the positive connecting piece 81 or the negative connecting piece 82. The positive tabs of the positive tab assembly 2 are welded to the positive connecting piece 81, and the negative tabs of the negative tab assembly 5 are welded to the negative connecting piece 82. The positive tab assembly 2 includes multiple positive tabs. During welding, the ends of the multiple positive tabs facing away from the positive electrode piece 11 are first overlapped together, and then welded to the same surface of the positive connecting piece 81 to avoid incomplete welding. The negative tab assembly 5 includes multiple negative tabs. During welding, the ends of the multiple negative tabs facing away from the negative electrode piece 13 are first overlapped together, and then welded to the same surface of the negative connecting piece 82 to avoid incomplete welding.

[0064] In one embodiment, the battery cell includes at least two winding cores. In the at least two winding cores, the tab assemblies of adjacent winding cores are aligned with each other. A connecting tab is welded to the tab assemblies of the adjacent two winding cores.

[0065] In one embodiment, the connecting piece 8 is a U-shaped connecting piece, including opposing first and second extensions. The first extension is welded to the tab assembly of one of two adjacent winding cores. The second extension is welded to the tab assembly of the other of the two adjacent winding cores.

[0066] In one embodiment, the electrode assembly includes a first electrode assembly 3 and a second electrode assembly 4. The first electrode assemblies 3 of two adjacent winding cores are arranged adjacent to each other.

[0067] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A type of winding core, characterized in that, include: The wound body includes a positive electrode sheet, a separator, and a negative electrode sheet that are sequentially stacked and wound together; A tab assembly is disposed at the axial end of the wound body. The tab assembly includes multiple tabs, which are respectively connected to different winding layers of the same electrode sheet and are aligned with each other. The axial direction of the wound body is the height direction of the tabs, and the height of the multiple tabs gradually decreases along the alignment direction of the multiple tabs.

2. The winding core according to claim 1, characterized in that, The electrode assembly includes a first electrode assembly and a second electrode assembly. The first electrode assembly and the second electrode assembly are located at the same axial end of the winding body, respectively disposed on both sides of the winding axis of the winding body, and are aligned with each other.

3. The winding core according to claim 2, characterized in that, The number of electrodes in the first electrode group is the same as the number of winding layers of the electrode sheet, and the direction in which the plurality of electrodes are aligned is from the second electrode group to the first electrode group.

4. The winding core according to claim 1, characterized in that, The winding direction of the winding body is the width direction of the tabs, and the width of the multiple tabs gradually decreases along the alignment direction of the multiple tabs.

5. The winding core according to claim 1, characterized in that, The width of the plurality of tabs gradually decreases along the direction away from the winding body.

6. The winding core according to claim 1, characterized in that, The side of the electrode tab opposite to the electrode plate is arc-shaped; or, The two ends of the tab on the side away from the electrode plate are chamfered.

7. The winding core according to claim 1, characterized in that, The electrode group is a first polarity electrode group, and the winding core also includes a second polarity electrode group. The second polarity electrode group and the first polarity electrode group are respectively disposed at both ends of the same axial end of the winding body. One of the first polarity electrode group and the second polarity electrode group is a positive electrode group, and the other is a negative electrode group.

8. The winding core according to claim 7, characterized in that, The first polarity tab group is a positive tab group, and the second polarity tab group is a negative tab group, including multiple negative tabs. The multiple negative tabs are respectively connected to different winding layers of the negative electrode sheet and are aligned with each other. Along the alignment direction of the multiple negative tabs, the height of the multiple negative tabs gradually decreases.

9. A battery cell, characterized in that, include: Connecting piece; In the winding core as described in any one of claims 1-8, the tabs in the tab assembly are overlapped at the ends opposite to the electrode sheet and welded to the same side of the connecting piece.

10. The battery cell according to claim 9, characterized in that, The battery cell includes at least two winding cores, the tabs of the at least two winding cores are aligned, and the connecting piece is welded to the tabs of two adjacent winding cores.

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