Pole piece, roll core and cylindrical power battery

Abstract

The utility model discloses a pole piece, a roll core and a cylindrical power battery, a tab area is formed at the upper part of the pole piece, a plurality of interval grooves are distributed in the tab area along the winding direction, so that a plurality of tabs are formed in the tab area, and every two adjacent tabs are sequentially defined as a first tab and a second tab along the winding direction; the interval groove comprises a linear groove and a bottom groove connected to the linear groove, the linear groove comprises a first side edge and a second side edge, the bottom groove comprises a third side edge tangentially connected to the first side edge and a fourth side edge connected to the second side edge, and the third side edge is a convex arc and bends and extends towards the second tab from the position connected with the first side edge; the end point, away from the first side edge, of the third side edge is connected with the end point, away from the second side edge, of the fourth side edge. The whole fourth side edge does not exceed the straight line where the second side edge is located. According to the utility model, stress concentration points such as inflection points / sharp points caused by only linear grooves between the tabs can be eliminated, and the risk that the pole piece is stressed and fractured when the tabs are wound and flattened is reduced.

Description

Technical Field

[0001] The utility model relates to the field of batteries, in particular to a pole piece, a winding core and a cylindrical power battery. Background Art

[0002] At present, full-tab large cylindrical lithium-ion / sodium-ion batteries have gradually become mainstream products in the new energy industry due to their high energy density, good capacity consistency, and ability to support high-rate charge and discharge. Conventional full-tab cylindrical batteries are flattened / patted after winding and then welded with collector plates to connect internal and external circuits. They have the following common defects:

[0003] (1) To ensure the laser penetration welding effect of the collector plate of the copper / aluminum foil full-pole ear of the cylindrical power battery, the surface is generally denser after being flattened / patted, resulting in a longer electrolyte injection time during production (slow electrolyte infiltration), which significantly affects the production capacity of cylindrical batteries.

[0004] (2) Please refer to Figure 1 and Figure 2 The copper / aluminum foil full-pole ears of cylindrical power batteries usually adopt parallel line film cutting full-pole ears. There are inflection points / sharp points at the roots, which easily form stress concentration points D. When the positive / negative electrode sheets are wound and flattened, they are easily broken by the force, which significantly affects the production yield of cylindrical batteries.

[0005] (3) Please continue reading Figure 1 and Figure 2 The copper / aluminum foil full-pole ears of cylindrical power batteries usually use parallel line film-cut full-pole ears (narrow and long straight grooves are between adjacent pole ears). After winding and flattening, there are almost no gaps between the membrane-cut pole ears, which can easily lead to poor consistency in the absorption of electrolyte by the positive and negative electrodes, thus affecting the battery cycle life. Utility Model Content

[0006] The purpose of the present utility model is to provide a pole piece, a winding core and a cylindrical power battery, which can solve at least one technical problem mentioned in the above background technology.

[0007] In order to achieve the above-mentioned purpose, the utility model provides a pole piece for a cylindrical power battery, wherein a pole lug area is formed on the upper part of the pole piece, and a plurality of spacing grooves are distributed in the pole lug area along the winding direction. The pole lug area forms a plurality of pole lugs by separation of the plurality of spacing grooves, and every two adjacent pole lugs are defined as a first pole lug and a second pole lug in sequence along the winding direction, and the spacing groove includes a straight line groove penetrating upward and a bottom groove connected to the bottom end of the straight line groove, and the straight line groove includes a first side and a second side parallel to each other which serve as the side of the first pole lug and the side of the second pole lug respectively, and the bottom groove includes a third side tangently connected to the bottom end point of the first side and a fourth side connected to the bottom end point of the second side, the third side is a convex arc and bends and extends from the position connected to the first side toward the second pole lug, and the end point of the third side away from the first side is connected to the end point of the fourth side away from the second side, and the fourth side as a whole does not exceed the straight line where the second side is located.

[0008] Optionally, the fourth side is located on an extension line of the second side.

[0009] Optionally, the fourth side protrudes into the second pole lug relative to the second side, so that the bottom groove is recessed into the bottom of the second pole lug, and the bottom groove is configured to form a liquid seepage hole of the winding core.

[0010] Optionally, the fourth side is a convex arc.

[0011] Optionally, the fourth side is smoothly connected to the third side.

[0012] Optionally, a bottom endpoint of the first side extends downward beyond a bottom endpoint of the second side.

[0013] Optionally, the spacing groove is in the shape of a musical note.

[0014] Optionally, the linear groove is inclined from top to bottom toward the winding direction.

[0015] In order to achieve the above-mentioned purpose, the utility model also provides a winding core, comprising a positive electrode wound pole sheet and a negative electrode wound pole sheet isolated from each other, at least one of the positive electrode wound pole sheet and the negative electrode wound pole sheet is formed by winding the pole sheet as described above.

[0016] In order to achieve the above-mentioned purpose, the utility model also provides a cylindrical power battery, including the winding core as described above.

[0017] In the utility model, a bottom groove is connected to the bottom of the linear groove between the first pole lug and the second pole lug, wherein the bottom groove includes a third side connected tangentially to the bottom end point of the first side of the linear groove and a fourth side connected to the bottom end point of the second side of the linear groove, the third side is a convex arc and bends and extends from the position connected to the first side toward the second pole lug, the end point of the third side away from the first side is connected to the end point of the fourth side away from the second side, and the fourth side as a whole does not exceed the straight line where the second side is located, that is, the third side as a convex arc at least extends to the straight line where the second side is located. Since one end point of the third side as a convex arc is tangentially connected to the bottom end point of the first side, and the third side at least extends to the straight line where the second side is located, stress concentration points such as inflection points / sharp points caused by only having linear grooves between the pole lugs can be eliminated, reducing the risk of the pole piece being fractured by force when winding and flattening the pole lugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of a traditional pole piece.

[0019] Figure 2 Schematic diagram of the structure of a traditional winding core.

[0020] Figure 3 It is a schematic diagram of the structure of the pole piece of an embodiment of the utility model.

[0021] Figure 4 for Figure 3 Enlarged view of part A in the middle.

[0022] Figure 5 A schematic structural diagram of a winding core according to an embodiment of the utility model.

[0023] Figure 6 It is a schematic diagram of the partial structure of a pole piece according to another embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to explain the technical content, structural features and effects achieved by the present invention in detail, the following is a detailed description in conjunction with the implementation modes and the accompanying drawings.

[0025] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0026] See also Figures 3 to 6The embodiment of the utility model discloses a pole piece 1 for a cylindrical power battery. A pole piece 1 is formed with a pole lug area 10 on the upper part of the pole piece 1. The pole lug area 10 is provided with a plurality of spacing grooves 11 along the winding direction (from right to left in the figure). The pole lug area 10 is separated by a plurality of spacing grooves 11 to form a plurality of pole lugs. Every two adjacent pole lugs are defined as a first pole lug 12 and a second pole lug 13 in sequence along the winding direction. The spacing groove 11 includes a straight groove 14 penetrating upward and a bottom groove 15 connected to the bottom end of the straight groove 14. The straight groove 14 includes a first side 16 and a second side 17 which are parallel to each other and serve as the side of the first pole lug 12 and the side of the second pole lug 13, respectively. The bottom groove 15 includes a third side 18 tangentially connected to the bottom end point of the first side 16 and a fourth side 19 connected to the bottom end point of the second side 17. The third side 18 is a convex arc (a smooth curve that convexes as a whole) and is bent and extended from the position connected to the first side 16 toward the second pole lug 13. The end point of the third side 18 away from the first side 16 is connected to the end point of the fourth side 19 away from the second side 17, so that the bottom groove 15 is defined by the third side 18 and the fourth side 19. The fourth side 19 as a whole does not exceed the straight line where the second side 17 is located, that is, the fourth side 19 is located at the second pole ear 13 and does not exceed the boundary line of the second pole ear 13 formed by the second side 17 as a whole.

[0027] In the utility model, a bottom groove 15 is connected to the bottom of the linear groove 14 between the first pole ear 12 and the second pole ear 13, wherein the bottom groove 15 includes a third side 18 tangentially connected to the bottom end point of the first side 16 of the linear groove 14 and a fourth side 19 connected to the bottom end point of the second side 17 of the linear groove 14, the third side 18 is a convex arc (can be a circular arc, an elliptical arc, a parabolic arc, etc.) and is bent and extended from the position connected to the first side 16 toward the second pole ear 13, the end point of the third side 18 away from the first side 16 is connected to the end point of the fourth side 19 away from the second side 17, and the fourth side 19 as a whole does not exceed the straight line where the second side 17 is located, that is, the third side 18 as a convex arc at least extends to the straight line where the second side 17 is located. Since the third side 18 as a convex arc is tangentially connected to the bottom end point of the first side 16, and the third side 18 extends at least to the straight line where the second side 17 is located, stress concentration points such as turning points / sharp points between the pole ears caused by only straight grooves 14 can be eliminated, reducing the risk of the pole piece 1 being fractured by force when winding and flattening the pole ears.

[0028] See also Figures 3 to 5In some embodiments, the fourth side 19 protrudes into the second pole tab 13 relative to the second side 17, so that the bottom groove 15 is recessed into the bottom of the second pole tab 13, and the bottom groove 15 is configured to form a liquid seepage hole 51 of the winding core 5. Since the bottom groove 15 can form the liquid seepage hole 51 of the winding core 5 after the winding core 5 is formed (by winding and flattening), it is convenient for the electrolyte to penetrate and absorb quickly, which is conducive to realizing the rapid injection production of cylindrical power batteries and improving the cycle life of cylindrical power batteries.

[0029] Specifically, the fourth side 19 is a convex arc. The convex arc can be a circular arc, an elliptical arc, a parabolic arc, etc. Of course, the fourth side 19 is not limited to a convex arc form, nor is it limited to a smooth curve, for example, it can have a sharp corner.

[0030] Specifically, the fourth side 19 and the third side 18 are smoothly connected, but this is not limited thereto.

[0031] Specifically, the bottom end point of the first side 16 extends downward beyond the bottom end point of the second side 17. However, this is not limited thereto.

[0032] Specifically, the spacing groove 11 is in the shape of a musical note.

[0033] In some embodiments, the linear grooves 14 are inclined from top to bottom toward the winding direction.

[0034] See also Figure 6 In this embodiment, the fourth side 19 is located on the extension line of the second side 17 . In this case, the fourth side 19 can be regarded as a part of the second side 17 .

[0035] Please combine Figures 3 to 6 The utility model further discloses a winding core 5, comprising a positive electrode winding pole sheet and a negative electrode winding pole sheet isolated from each other (isolated by a diaphragm), at least one of the positive electrode winding pole sheet and the negative electrode winding pole sheet is formed by winding the pole sheet 1 as described above.

[0036] In the utility model, a bottom groove 15 is connected to the bottom of the linear groove 14 between the first pole ear 12 and the second pole ear 13, wherein the bottom groove 15 includes a third side 18 tangentially connected to the bottom end point of the first side 16 of the linear groove 14 and a fourth side 19 connected to the bottom end point of the second side 17 of the linear groove 14, the third side 18 is a convex arc and bends and extends from a position connected to the first side 16 toward the second pole ear 13, the end point of the third side 18 away from the first side 16 is connected to the end point of the fourth side 19 away from the second side 17, and the fourth side 19 as a whole does not exceed the straight line where the second side 17 is located, that is, the third side 18 as a convex arc extends at least to the straight line where the second side 17 is located. Since one end point of the third side 18 as a convex arc is tangentially connected to the bottom end point of the first side 16, and the third side 18 extends at least to the straight line where the second side 17 is located, stress concentration points such as inflection points / sharp points between the pole ears caused by only straight grooves 14 can be eliminated, reducing the risk of the pole piece 1 being fractured by force when winding and flattening the pole ears.

[0037] exist Figures 3 to 5 In the example, after the core 5 is formed by winding and flattening, the bottom groove 15 forms the liquid seepage hole 51 of the core 5, which is convenient for the rapid penetration and absorption of the electrolyte, and is conducive to the rapid injection production of the cylindrical power battery and the improvement of the cycle life of the cylindrical power battery.

[0038] The utility model also discloses a cylindrical power battery, comprising the winding core 5 as described above.

[0039] The above disclosure is only a preferred example of the present invention, and its role is to facilitate the technical personnel in this field to understand and implement it. Of course, it cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. A pole piece for a cylindrical power battery, characterized in that: A pole lug region is formed on the upper portion of the pole piece, and a plurality of spacing grooves are distributed in the pole lug region along the winding direction. The pole lug region forms a plurality of pole lugs by separating the plurality of spacing grooves, and every two adjacent pole lugs are defined as a first pole lug and a second pole lug in sequence along the winding direction, and the spacing grooves include a straight groove penetrating upward and a bottom groove connected to the bottom end of the straight groove, and the straight groove includes a first side and a second side parallel to each other, which serve as the side of the first pole lug and the side of the second pole lug respectively, and the bottom groove includes a third side tangently connected to the bottom end point of the first side and a fourth side connected to the bottom end point of the second side, the third side is a convex arc and bends and extends from the position connected to the first side toward the second pole lug, the end point of the third side away from the first side is connected to the end point of the fourth side away from the second side, and the fourth side as a whole does not exceed the straight line where the second side is located.

2. The pole piece according to claim 1, characterized in that: The fourth side is located on an extension line of the second side.

3. The pole piece according to claim 1, characterized in that: The fourth side protrudes into the second pole tab relative to the second side, so that the bottom groove is recessed into the bottom of the second pole tab, and the bottom groove is configured to form a liquid seepage hole of the winding core.

4. The pole piece according to claim 3, characterized in that: The fourth side is a convex arc.

5. The pole piece according to claim 3 or 4, characterized in that: The fourth side edge is smoothly connected to the third side edge.

6. The pole piece according to claim 3 or 4, characterized in that: A bottom endpoint of the first side extends downward beyond a bottom endpoint of the second side.

7. The pole piece according to claim 1, characterized in that: The linear groove is inclined from top to bottom toward the winding direction.

8. A winding core, characterized in that: It comprises a positive electrode wound pole sheet and a negative electrode wound pole sheet isolated from each other, and at least one of the positive electrode wound pole sheet and the negative electrode wound pole sheet is formed by winding the pole sheet according to any one of claims 1 to 7.

9. A cylindrical power battery, characterized in that: Comprising the winding core as claimed in claim 8.

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