Roll core battery cell and battery

Abstract

The utility model relates to the technical field of batteries, in particular to a roll core battery cell and a battery, the roll core battery cell comprises a roll core pole group, a positive tab assembly and a negative tab assembly, the positive tab assembly and the negative tab assembly are respectively connected with the roll core pole group, the positive tab assembly and the negative tab assembly are both arranged at the end part of the roll core pole group in a first direction, each of the positive tab assembly and the negative tab assembly is of an integrally connected multi-layer solid structure, each layer of the multi-layer solid structure is stacked along a first direction, and the size of the multi-layer solid structure in the first direction is 0.8-2.5 mm. According to the roll core battery cell and the battery provided by the invention, the extending size of the tab relative to the roll core pole group is controlled, and the space utilization rate of the battery cell is improved; the connection strength and stability of the tabs are improved, the probability that the tabs are prone to local tearing, damage, breakage and the like under the extreme conditions of vibration, collision and the like of the battery is reduced, the stability of the battery cell is improved, and the service life of the battery cell is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a wound core battery and a battery. Background Art

[0002] At present, the tabs of the electrode group of the battery cell need to extend a long distance from the electrode group, and the electrical connection between the winding core electrode group and the electrical connection structure of the connecting plate, pole column, etc. is realized by bending the tabs. However, the current tabs are relatively long relative to the extension size of the electrode group, and need to be bent repeatedly (for example, Chinese patent documents CN210744062U, CN101276931A, etc.). On the one hand, in the structure where the electrode group is connected to the outside through the tabs, the bending of the tabs needs to occupy a large battery cell space; on the other hand, the bending structure of the long tabs is relatively thin and has poor stability. Under extreme conditions such as vibration and collision, the tabs are very prone to partial tearing, damage or even breakage, which in turn causes short circuits and other phenomena in the battery cell. Utility Model Content

[0003] The purpose of the present application is to provide a wound battery cell and a battery, so as to solve the technical problems existing in the prior art to a certain extent that the bending of the pole ear requires a large battery cell space and the bending structure of the long pole ear is relatively thin and has poor stability. Under extreme conditions such as vibration and collision, the pole ear is very likely to be partially torn, damaged or even broken, which may lead to short circuit and other phenomena in the battery cell.

[0004] According to the first aspect of the present application, a wound battery cell is provided, comprising a wound electrode group, a positive electrode ear assembly and a negative electrode ear assembly, wherein the positive electrode ear assembly and the negative electrode ear assembly are respectively connected to the wound electrode group, and the positive electrode ear assembly and the negative electrode ear assembly are both arranged at the ends of the wound electrode group in the first direction, and the positive electrode ear assembly and the negative electrode ear assembly are both multi-layer solid structures connected as a whole, and each layer of the multi-layer solid structure is stacked along the first direction, and the size of the multi-layer solid structure in the first direction is 0.8 mm to 2.5 mm.

[0005] Preferably, the core electrode group comprises a positive core and a negative core which are wound around each other;

[0006] When the positive winding core and the negative winding core are both in an unwound state, the positive winding core and the negative winding core are both in a strip shape extending along a second direction, and the second direction is perpendicular to the first direction.

[0007] Preferably, a plurality of positive electrode ears are provided at one end of the positive winding core in the first direction, and the plurality of positive electrode ears are arranged at intervals along the second direction. When the positive winding core is wound into the winding core electrode group, the plurality of positive electrode ears overlap in a third direction to form the positive electrode ear assembly, and the third direction is perpendicular to a plane defined by the first direction and the second direction.

[0008] A plurality of negative electrode ears are arranged at one end of the negative winding core in the first direction, and the plurality of negative electrode ears are arranged at intervals along the second direction. When the negative winding core is wound into the winding core electrode group, the plurality of negative electrode ears overlap in the third direction to form the negative electrode ear assembly.

[0009] Preferably, the positive electrode ear portion comprises a first connection end and a first free end opposite to each other, the positive electrode ear portion is connected to the positive winding core via the first connection end, and relative to the first free end, a first fold line extending along the second direction is provided on a side of the positive electrode ear portion close to the first connection end, and the positive electrode ear portion forms a bending angle at the first fold line, so that a portion of the positive electrode ear portion located between the first fold line and the first free end is perpendicular to the first direction;

[0010] The negative electrode ear portion includes a second connecting end and a second free end opposite to each other, and the negative electrode ear portion is connected to the negative winding core via the second connecting end. Relative to the second free end, a second fold line extending along the second direction is provided on one side of the negative electrode ear portion close to the second connecting end, and the negative electrode ear portion forms a bending angle at the second fold line so that a portion of the negative electrode ear portion located between the second fold line and the second free end is perpendicular to the first direction.

[0011] Preferably, the distance between the first connecting end and the first free end is 0.8 mm to 4 mm;

[0012] The distance between the second connecting end and the second free end is 0.8 mm to 4 mm.

[0013] Preferably, the positive electrode ear portion includes a plurality of first cutting portions, and when the positive electrode ear portion is not bent along the first folding line, the first cutting portion extends from the first free end along the first direction to the first connecting end, and the plurality of first cutting portions are arranged at equal intervals along the second direction to divide the positive electrode ear portion into a plurality of first connecting fingers;

[0014] The negative electrode ear portion includes a plurality of second cutting lines. When the negative electrode ear portion is not bent along the second fold line, the second cutting lines extend from the second free end along the first direction to the second connecting end. The plurality of second cutting lines are arranged at equal intervals along the second direction to divide the negative electrode ear portion into a plurality of second connecting fingers.

[0015] Preferably, the sizes of the first connecting finger and the second connecting finger in the second direction are both 0.2 mm to 1 mm.

[0016] Preferably, the sizes of the first connecting finger and the second connecting finger in the second direction are both 0.45 mm to 0.55 mm.

[0017] Preferably, the positive electrode tab assembly and the negative electrode tab assembly are both arranged at the same end of the wound electrode group in the first direction;

[0018] The positive electrode tab assembly and the negative electrode tab assembly are spaced apart from each other along the second direction.

[0019] According to a second aspect of the present application, a battery is provided, comprising the wound core battery cell described in any of the above technical solutions, and thus having all the beneficial technical effects of the wound core battery cell, which will not be described in detail herein.

[0020] Compared with the prior art, the beneficial effects of this application are:

[0021] The wound battery cell provided in the present application, by arranging the positive electrode ear assembly and the negative electrode ear assembly into a multi-layer solid structure in which each layer is stacked along a first direction, and controlling the size of the multi-layer solid structure in the first direction to be within the range of 0.8mm to 2.5mm, on the one hand, effectively controls the size of the ear (i.e., the positive electrode ear assembly and the negative electrode ear assembly) extending relative to the wound electrode group, thereby avoiding the ear from occupying too much battery cell space and improving the space utilization of the battery cell; on the other hand, designing the ear into a multi-layer solid structure can effectively increase the connection strength and stability of the ear, effectively reducing the probability of local tearing, damage, breakage, etc. of the ear in extreme conditions such as vibration and collision of the battery, thereby improving the stability and service life of the battery cell.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the axonometric structure of a wound core battery provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the front view structure of the positive winding core provided in an embodiment of the present application in an unfolded state;

[0026] Figure 3 This is a schematic diagram of the front view structure of the negative winding core provided in an embodiment of the present application in an unfolded state.

[0027] Reference numerals:

[0028] 1- wound electrode group; 11- positive winding core; 12- negative winding core; 2- positive electrode ear assembly; 20- positive electrode ear; 201- first connecting end; 202- first free end; 21- first connecting finger; 22- first cutting portion; 23- first fold line; 3- negative electrode ear assembly; 30- negative electrode ear; 301- second connecting end; 302- second free end; 31- second connecting finger; 32- second cutting portion; 33- second fold line.

[0029] F1-first direction; F2-second direction; F3-third direction. DETAILED DESCRIPTION

[0030] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0031] The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed, but merely represents the selected embodiments of the present application.

[0032] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0033] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] Refer to the following Figures 1 to 3 The invention describes a spiral wound battery cell and a battery according to some embodiments of the present application.

[0036] See also Figures 1 to 3 As shown, an embodiment of the first aspect of the present application provides a wound battery cell, which includes a wound electrode group 1, a positive electrode ear assembly 2 and a negative electrode ear assembly 3, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 are respectively connected to the wound electrode group 1, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 are both arranged at the end of the wound electrode group 1 in the first direction F1, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 are both connected as a whole multi-layer solid structure, each layer of the multi-layer solid structure is stacked along the first direction F1, and the size of the multi-layer solid structure in the first direction F1 is 0.8mm~2.5mm.

[0037] According to the wound battery cell provided by the above-mentioned technical features, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 are arranged into a multi-layer solid structure in which each layer is stacked along the first direction F1, and the size of the multi-layer solid structure in the first direction F1 is controlled within the range of 0.8mm to 2.5mm. On the one hand, the extension size of the electrode ear (i.e., the positive electrode ear assembly 2 and the negative electrode ear assembly) relative to the wound electrode group 1 is effectively controlled, thereby avoiding the electrode ear from occupying too much battery cell space and improving the space utilization rate of the battery cell; on the other hand, designing the electrode ear into a multi-layer solid structure can effectively increase the connection strength and stability of the electrode ear, effectively reducing the probability of local tearing, damage, breakage, etc. of the electrode ear in extreme conditions such as vibration and collision of the battery, thereby improving the stability and service life of the battery cell.

[0038] Preferably, the core electrode group 1 may include a positive core 11 and a negative core 12 wound around each other. Figure 2 and Figure 3 As shown, when the positive winding core 11 and the negative winding core 12 are both in an unwound state (ie, an unfolded state), the positive winding core 11 and the negative winding core 12 may both be in a strip shape extending along the second direction F2 .

[0039] It should be noted that the positive winding core 11 and the negative winding core 12 in the above-mentioned winding core pole group 1 can be arranged to overlap each other, and the above-mentioned winding core pole group 1 is formed by winding in a clockwise or counterclockwise direction from one end of the strip-like member where the positive winding core 11 and the negative winding core 12 overlap each other. The winding method and winding structure of the winding core pole group 1 are existing technologies in the field and will not be repeated here.

[0040] like Figures 1 to 3 As shown, F1 shown in the figure may be an example of the first direction F1, and F2 shown in the figure may be an example of the second direction F2, wherein the second direction F2 may be perpendicular to the first direction F1. For ease of description, a direction perpendicular to a plane determined by both the first direction F1 and the second direction F2 is defined as a third direction F3. F3 shown in the figure may be an example of the third direction F3.

[0041] Preferably, the size of the core electrode group 1 in the third direction F3 can be 15mm~30mm. In other words, the size of the core electrode group 1 formed by winding the positive core 11 and the negative core 12 together in the third direction F3 can be 15mm~30mm, so as to adapt to the size of existing battery cells.

[0042] Preferably, if Figure 2 As shown, a plurality of positive ear portions 20 are provided at one end of the positive winding core 11 in the first direction F1, and the plurality of positive ear portions 20 are arranged at intervals along the second direction F2. When the positive winding core 11 is wound into a winding core electrode group 1, the plurality of positive ear portions 20 overlap in the third direction F3 to form the positive ear assembly 2. In this way, by providing a plurality of positive ear portions 20 on the positive winding core 11, the output connection points of the positive winding core 11 are effectively increased, thereby effectively shortening the current flow path, reducing the structural internal resistance and system heat generation, and improving the performance of the battery.

[0043] It should be noted that the multiple layers in the multi-layer solid structure formed by the positive electrode ear assembly 2 can be understood as a multi-layer structure formed by overlapping the positive electrode ear parts 20 .

[0044] Similarly, if Figure 3The negative winding core 12 is provided with a plurality of negative electrode ears 30 at one end in the first direction F1, and the plurality of negative electrode ears 30 are arranged at intervals along the second direction F2. When the negative winding core 12 is wound into a winding core electrode group 1, the plurality of negative electrode ears 30 overlap in the third direction F3 to form the negative electrode ear assembly 3. In this way, by providing a plurality of negative electrode ears 30 on the negative winding core 12, the input connection points of the negative winding core 12 are effectively increased, thereby effectively shortening the current flow path, reducing the structural internal resistance and system heat generation, and improving the performance of the battery.

[0045] Correspondingly, the multiple layers in the multi-layer solid structure formed by the above-mentioned negative electrode ear assembly 3 can be understood as a multi-layer structure formed by overlapping the negative electrode ear parts 30 .

[0046] Preferably, if Figure 1 As shown, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 can be arranged at the same end of the core-wound electrode group 1 in the first direction F1. In this way, the positive electrode ear assembly 2 and the negative electrode ear assembly 3 both occupy the space on the same side of the core-wound electrode group 1, which is not only convenient for connecting the battery cells and wiring, but also can further save the space occupied by the ear.

[0047] The two opposite ends of the core electrode group 1 in the second direction F2 are defined as a first end and a second end. The positive ear 20 can be arranged close to the first end of the core electrode group 1, and the negative ear 30 can be arranged close to the second end of the core electrode group 1. When the positive core 11 and the negative core 12 are wound around each other, the positive ear 20 and the negative ear 30 are staggered with each other, so as to avoid interference between the positive ear 20 and the negative ear 30 during the winding process of the core battery.

[0048] However, it is not limited thereto, and as not shown in the figure, the positive electrode tab assembly 2 and the negative electrode tab assembly 3 may also be respectively disposed at two ends of the wound electrode group 1 in the first direction F1.

[0049] Preferably, if Figure 2As shown, the positive ear 20 may include a first connection end 201 and a first free end 202 opposite to each other. The positive ear 20 is connected to the positive winding core 11 via the first connection end 201. Relative to the first free end 202, a first fold line 23 extending along the second direction F2 is provided on one side of the positive ear 20 close to the first connection end 201. The positive ear 20 forms a bending angle at the first fold line 23, so that a portion of the positive ear 20 located between the first fold line 23 and the first free end 202 is perpendicular to the first direction F1, as shown in FIG. Therefore, the positive ear assembly 2 can be fitted with the end face of the core-wound electrode group 1 in the first direction F1. On the one hand, the contact area between the positive ear assembly 2 and the core-wound electrode group 1 is effectively improved, and the connection strength between the positive ear assembly 2 and the core-wound electrode group 1 and the stability of the setting of the positive ear assembly 2 are further improved; on the other hand, the bent positive ear portion 20 forms an end face perpendicular to the first direction F1 at the upper end of the positive ear assembly 2, which makes it easier to connect the positive ear assembly 2 with other positive electrode connection structures of the battery cell (for example, positive connecting pieces, positive pole columns, etc.).

[0050] Preferably, if Figure 2 As shown, the distance between the first connecting end 201 and the first free end 202 can be 0.8 mm to 4 mm. In other words, when the positive winding core 11 is in the unfolded state, the length of the positive electrode ear 20 in the first direction F1 (i.e. Figure 2 The S1 value shown can be 0.8 mm to 4 mm, so that the positive electrode ear portion 20 is bent at the end surface of the core-wound electrode group 1 in the first direction F1.

[0051] Similarly, if Figure 3 As shown, the negative electrode ear 30 may include a second connection end 301 and a second free end 302 opposite to each other, and the negative electrode ear 30 is connected to the negative winding core 12 via the second connection end 301. Relative to the second free end 302, a second fold line 33 extending along the second direction F2 is provided on one side of the negative electrode ear 30 close to the second connection end 301. The negative electrode ear 30 forms a bending angle at the second fold line 33 so that the portion of the negative electrode ear 30 located between the second fold line 33 and the second free end 302 is perpendicular to the first direction F1. The beneficial effects of this structure are similar to those of the above-mentioned positive electrode ear assembly 2 and are not repeated here.

[0052] Correspondingly, if Figure 3 As shown, the distance between the second connecting end 301 and the second free end 302 can be 0.8 mm to 4 mm. In other words, when the negative winding core 12 is in the unfolded state, the length of the negative electrode ear 30 in the first direction F1 (i.e. Figure 3The S2 value shown can be 0.8 mm to 4 mm, so that the negative electrode ear portion 30 is bent at the end surface of the wound electrode group 1 in the first direction F1.

[0053] Preferably, each layer of the positive electrode ear portion 20 in the positive electrode ear assembly 2 can be flattened layer by layer through a flattening process, so that the positive electrode ear assembly 2 forms the multi-layer solid structure. Correspondingly, each layer of the negative electrode ear portion 30 in the negative electrode ear assembly 3 can also be flattened layer by layer through a flattening process, so that the negative electrode ear assembly 3 forms the multi-layer solid structure.

[0054] However, it is not limited thereto, as long as each layer of the positive ear portion 20 in the positive ear assembly 2 (or each layer of the negative ear portion 30 in the negative ear assembly 3) can form a solid structure, the above-mentioned positive ear assembly 2 (or negative ear assembly 3) can also be made by other molding processes, such as a rolling process, a rolling process, etc.

[0055] It should be noted that the above-mentioned “the size of the multi-layer solid structure in the first direction F1 is 0.8 mm to 2.5 mm” can be understood as the size of the multi-layer solid structure in the first direction F1 formed by the above-mentioned positive electrode ear 20 (or negative electrode ear 30) after the bending and flattening process (i.e. Figure 1 The l value shown) is 0.8mm to 2.5mm.

[0056] Alternatively, if Figure 1 As shown, the positive electrode ears 20 stacked along the third direction F3 are separated by the midline of the core electrode group 1 in the second direction F2, and the positive electrode ears 20 located behind the midline are bent forward, and the positive electrode ears 20 located in front of the midline are bent backward. In the bending and flattening process of the positive electrode ear assembly 2, the positive electrode ears 20 on both sides of the midline are bent and flattened alternately in sequence from the midline to the edge, so as to form a multi-layer solid structure of the positive electrode ear assembly 2.

[0057] Similarly, the bent and flattened structure of the multi-layer solid structure of the negative electrode tab assembly 3 is similar to that of the positive electrode tab assembly 2 and will not be described in detail.

[0058] In an embodiment, preferably, Figure 2As shown, the positive ear 20 may include a plurality of first cutting portions 22. When the positive ear 20 is not bent along the first fold line 23 (i.e., in the unfolded state), the first cutting portion 22 extends from the first free end 202 along the first direction F1 to the first connecting end 201. The plurality of first cutting portions 22 are arranged at equal intervals along the second direction F2 to divide the positive ear 20 into a plurality of first connecting fingers 21. In this way, the positive ear 20 is divided into a plurality of first connecting fingers 21 by the first cutting portions 22, so that the positive ear 20 is more conducive to deformation. Furthermore, under the action of the flattening process, the multi-layer positive ear 20 can be more tightly connected, thereby improving the compactness of the multi-layer solid structure and further improving the setting stability of the positive ear assembly 2.

[0059] It should be noted that Figure 2 Taking the orientation shown as an example, the first cutting portion 22 can be understood as the part of the positive electrode ear 20 located on the left side and the part on the right side of the first cutting portion 22 are not connected in the area where the first cutting portion 22 is located. In other words, the positive electrode ear 20 can be cut along the first cutting portion 22 to form the plurality of first connecting fingers 21.

[0060] Preferably, the size of the first connecting finger 21 in the second direction F2 may be 0.2 mm to 1 mm, so as to facilitate the bending and flattening of the first connecting finger 21 .

[0061] Preferably, the size of the first connecting finger 21 in the second direction F2 may be 0.45 mm to 0.55 mm, so as to further facilitate the bending and flattening of the first connecting finger 21 .

[0062] Similarly, if Figure 3 As shown, the negative electrode ear 30 may include a plurality of second cutting portions 32. When the negative electrode ear 30 is not bent along the second fold line 33, the second cutting portion 32 extends from the second free end 302 along the first direction F1 to the second connecting end 301. The plurality of second cutting portions 32 are arranged at equal intervals along the second direction F2 to divide the negative electrode ear 30 into a plurality of second connecting fingers 31. The beneficial effect of the second connecting finger 31 is similar to that of the first connecting finger 21, and the structure of the second cutting portion 32 is similar to that of the first cutting portion 22, which will not be repeated here.

[0063] Preferably, the size of the second connecting finger 31 in the second direction F2 may also be 0.2 mm to 1 mm, so as to facilitate the bending and flattening of the second connecting finger 31 .

[0064] Preferably, the size of the second connecting finger 31 in the second direction F2 may also be 0.45 mm to 0.55 mm, so as to further facilitate the bending and flattening of the second connecting finger 31 .

[0065] An embodiment of the second aspect of the present application further provides a battery, comprising the wound core battery cell described in any of the above embodiments, and thus having all the beneficial technical effects of the wound core battery cell, which will not be elaborated here.

[0066] Optionally, the battery may include one or more of the battery cells.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wound core battery cell, characterized in that: It includes a wound core electrode group, a positive electrode ear assembly and a negative electrode ear assembly, wherein the positive electrode ear assembly and the negative electrode ear assembly are respectively connected to the wound core electrode group, and the positive electrode ear assembly and the negative electrode ear assembly are both arranged at the end of the wound core electrode group in the first direction, and the positive electrode ear assembly and the negative electrode ear assembly are both connected as a whole multi-layer solid structure, and each layer of the multi-layer solid structure is stacked along the first direction, and the size of the multi-layer solid structure in the first direction is 0.8mm~2.5mm.

2. The wound core battery according to claim 1, characterized in that: The core electrode group includes a positive core and a negative core that are wound around each other; When the positive winding core and the negative winding core are both in an unwound state, the positive winding core and the negative winding core are both in a strip shape extending along a second direction, and the second direction is perpendicular to the first direction.

3. The wound core battery according to claim 2, characterized in that: A plurality of positive electrode ears are arranged at one end of the positive winding core in the first direction, and the plurality of positive electrode ears are arranged at intervals along the second direction. When the positive winding core is wound into the winding core electrode group, the plurality of positive electrode ears overlap in a third direction to form the positive electrode ear assembly, and the third direction is perpendicular to a plane defined by the first direction and the second direction. A plurality of negative electrode ears are arranged at one end of the negative winding core in the first direction, and the plurality of negative electrode ears are arranged at intervals along the second direction. When the negative winding core is wound into the winding core electrode group, the plurality of negative electrode ears overlap in the third direction to form the negative electrode ear assembly.

4. The wound core battery according to claim 3, characterized in that: The positive electrode ear portion comprises a first connection end and a first free end opposite to each other, the positive electrode ear portion is connected to the positive winding core via the first connection end, and relative to the first free end, a first fold line extending along the second direction is provided on a side of the positive electrode ear portion close to the first connection end, and the positive electrode ear portion forms a bending angle at the first fold line, so that a portion of the positive electrode ear portion located between the first fold line and the first free end is perpendicular to the first direction; The negative electrode ear portion includes a second connecting end and a second free end opposite to each other, and the negative electrode ear portion is connected to the negative winding core via the second connecting end. Relative to the second free end, a second fold line extending along the second direction is provided on one side of the negative electrode ear portion close to the second connecting end, and the negative electrode ear portion forms a bending angle at the second fold line so that a portion of the negative electrode ear portion located between the second fold line and the second free end is perpendicular to the first direction.

5. The wound core battery according to claim 4, characterized in that: The distance between the first connecting end and the first free end is 0.8 mm to 4 mm; The distance between the second connecting end and the second free end is 0.8 mm to 4 mm.

6. The wound core battery according to claim 5, characterized in that: The positive electrode ear portion includes a plurality of first cutting portions, and when the positive electrode ear portion is not bent along the first fold line, the first cutting portions extend from the first free end along the first direction to the first connecting end, and the plurality of first cutting portions are arranged at equal intervals along the second direction to divide the positive electrode ear portion into a plurality of first connecting fingers; The negative electrode ear portion includes a plurality of second cutting lines. When the negative electrode ear portion is not bent along the second fold line, the second cutting lines extend from the second free end along the first direction to the second connecting end. The plurality of second cutting lines are arranged at equal intervals along the second direction to divide the negative electrode ear portion into a plurality of second connecting fingers.

7. The wound core battery according to claim 6, characterized in that: The sizes of the first connecting finger and the second connecting finger in the second direction are both 0.2 mm to 1 mm.

8. The wound core battery according to claim 6, characterized in that: The sizes of the first connecting finger and the second connecting finger in the second direction are both 0.45 mm to 0.55 mm.

9. The wound core battery according to any one of claims 2 to 8, characterized in that: The positive electrode tab assembly and the negative electrode tab assembly are both arranged at the same end of the wound electrode group in the first direction; The positive electrode tab assembly and the negative electrode tab assembly are spaced apart from each other along the second direction.

10. A battery, characterized in that: A wound core battery cell comprising the wound core battery cell according to any one of claims 1 to 9.

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