Roll core structure and battery

Abstract

The utility model provides a roll core structure and a battery, the roll core structure comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece comprises a first straight section taking a winding starting end of the first pole piece as a starting point and a first corner section connected with the first straight section, and the first straight section and the first corner section are sequentially arranged along a first direction; the second pole piece comprises a second corner section taking the winding starting end of the second pole piece as a starting point, at least one side of the second corner section is coated with an anode active material layer, and the edge of the anode active material layer is flush with the winding starting end of the second pole piece; the diaphragm, the first pole piece, the diaphragm and the second pole piece are arranged in a laminated manner and are wound along a first direction to form a battery cell main body; and the winding starting end of the second pole piece is projected in the first corner section along the thickness direction of the second corner section. The battery comprises a packaging film and the roll core structure. According to the roll core structure and the battery, the movement between the pole pieces in the winding direction can be effectively limited, and the roll core structure is smoother.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a winding core structure and a battery. BACKGROUND

[0002] In the technical field of battery manufacturing, the winding core structure is usually formed by laminating and winding an anode sheet, a separator and a cathode sheet. However, at the winding starting end, it is difficult to achieve close adhesion between the anode sheet and the cathode sheet, and the poor adhesion between the two will cause lithium precipitation during the battery cycle, thereby affecting the overall performance of the battery. CONTENT OF THE UTILITY MODEL

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a winding core structure which can make the first electrode sheet and the second electrode sheet more closely adhere at the winding starting end, thereby improving the lithium precipitation phenomenon of the battery to ensure the performance of the battery.

[0004] The present application also provides a battery with the above winding core structure.

[0005] According to the winding core structure of the present application, the winding core structure comprises a first electrode sheet, a second electrode sheet and a separator;

[0006] The first electrode sheet comprises a first flat section starting from the winding starting end of the first electrode sheet, and a first corner section connected with the first flat section, and the first flat section and the first corner section are arranged in sequence along the first direction;

[0007] The second electrode sheet comprises a second corner section starting from the winding starting end of the second electrode sheet, at least one side of the second corner section is coated with an anode active material layer, and the edge of the anode active material layer is flush with the winding starting end of the second electrode sheet;

[0008] The first electrode sheet, the separator and the second electrode sheet are laminated and arranged, and are wound along the first direction to form a battery main body;

[0009] Wherein, along the thickness direction of the second corner section, the winding starting end of the second electrode sheet is projected in the first corner section.

[0010] According to the winding core structure provided in the embodiments of the present application, the following beneficial effects are achieved: the first corner section and the second corner section are blocked by the diaphragm, so as to avoid short circuit caused by contact between the first corner section and the second corner section; the first corner section and the second corner section are both curved sections, and the first corner section and the second corner section are cooperatively driven to wind, so that the driving force direction forms a certain angle with the two curved sections, thereby effectively limiting the relative movement between the first pole piece and the second pole piece; in addition, the second corner section generates tension during the bending deformation process, so that the second corner section has a tendency to restore to the original state, thereby the second corner section can be more closely attached to the first corner section, which is beneficial to improve the lithium precipitation phenomenon of the battery and improve the performance and prolong the service life of the battery.

[0011] According to some embodiments of the present application, the first corner section is provided with a first groove on the side close to the second corner section, and at least a part of the second corner section is located in the first groove.

[0012] According to some embodiments of the present application, the side of the first corner section facing the second corner section is coated with a cathode active material layer, the cathode active material layer is provided with a first groove, and the ratio of the depth of the first groove to the thickness of the cathode active material layer ranges from 0.1 to 1.

[0013] According to some embodiments of the present application, the winding starting end of the second pole piece is located in the first groove.

[0014] According to some embodiments of the present application, in the first direction, the length of the first groove is 0.2 mm to 3 mm.

[0015] According to some embodiments of the present application, the first corner section is provided with a first groove on the side close to the second corner section, and a fixed adhesive paper is arranged in the first groove, and the fixed adhesive paper is located between the first corner section and the second corner section.

[0016] According to some embodiments of the present application, the side of the second corner section away from the first corner section is provided with an anode active material layer, the anode active material layer is provided with a second groove, and the ratio of the depth of the second groove to the thickness of the anode active material layer ranges from 0.1 to 1.

[0017] And / or, the side of the second corner section facing the first corner section is provided with an anode active material layer, the anode active material layer is provided with a third groove, and the ratio of the depth of the third groove to the thickness of the anode active material layer ranges from 0.1 to 1.

[0018] According to some embodiments of the present application, the side of the second corner section facing the first corner section is provided with a limiting groove, and the first corner section is attached to the limiting groove.

[0019] According to some embodiments of the present application, the length of the second corner section is 0 to 2 mm.

[0020] The battery according to the embodiment of the present application comprises a packaging film and the winding core structure in any of the above embodiments, and the packaging film is used to wrap the winding core structure.

[0021] The battery according to the embodiment of the present application has at least the following beneficial effects: the packaging film is used to wrap the winding core structure, thereby ensuring the sealing of the battery, and the winding core structure is more flat, so that the battery is also more flat, which is beneficial to ensure the performance of the battery.

[0022] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be understood by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described below in combination with the drawings and embodiments, wherein:

[0024] Figure 1 FIG. 1 is a schematic view of a winding core structure according to a first embodiment of the present application;

[0025] Figure 2 FIG. 2 is a schematic view of a winding core structure according to a second embodiment of the present application;

[0026] Figure 3 FIG. 3 is a schematic view of a winding core structure according to a third embodiment of the present application;

[0027] Figure 4 FIG. 4 is a schematic view of a winding core structure according to a fourth embodiment of the present application; Figure 3 FIG. 5 is a partial enlarged view of position A in FIG. 4;

[0028] Figure 5 FIG. 6 is a schematic view of a structure of a second pole piece according to an embodiment of the present application;

[0029] Figure 6 FIG. 7 is a schematic view of a structure of a first pole piece and a second pole piece according to an embodiment of the present application.

[0030] Reference signs: first pole piece 100, first flat section 110, first corner section 120, first groove 121;

[0031] Second pole piece 200, second corner section 210, second groove 220, third groove 230, limiting groove 240;

[0032] Separator 300;

[0033] Fixing adhesive paper 400. DETAILED DESCRIPTION

[0034] Embodiments of the present application are described below in the detailed description and illustrated in the accompanying drawings by which like or similar elements, structures and / or functions have been given the same reference numerals and functionalities (which are intended to indicate like or similar elements) are not needed to be repeatedly described with their functionalities. The embodiments described below are examples only, and are not to be construed as limiting the present application.

[0035] In the description of the present application, if the orientation description such as up, down, front, back, left, right and the like is referred to, the orientation or position relationship shown in the drawings is based on the orientation or position relationship, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0036] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is two or more, greater than, less than, more than and the like are understood as not including the number, above, below, within and the like are understood as including the number. If the first, second is described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of technical features indicated.

[0037] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0038] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0039] The embodiments of the present application are described below in combination with the accompanying drawings of the specification:

[0040] Reference Figure 1According to the first embodiment of the present application, the core structure comprises a first pole piece 100, a second pole piece 200 and a separator 300. The first pole piece 100 comprises a first flat section 110 starting from the winding start end of the first pole piece 100, and a first corner section 120 connected to the first flat section 110. The first flat section 110 and the first corner section 120 are arranged in sequence along the first direction, i.e. the first flat section 110 extends from the winding start end of the first pole piece 100 to the first corner section 120. The second pole piece 200 comprises a second corner section 210 starting from the winding start end of the second pole piece 200. At least one side of the second corner section 210 is coated with an anode active material layer, and the edge of the anode active material layer is flush with the winding start end of the second pole piece 200. The first pole piece 100, the separator 300 and the second pole piece 200 are arranged in layers and wound to form a core body along the first direction. The separator 300 is used to prevent the first pole piece 100 and the second pole piece 200 from contacting and short-circuiting.

[0041] The winding start end of the second pole piece 200 projects into the first corner section 120 along the thickness direction of the second corner section 210, which is perpendicular to the first direction. Specifically, during the winding operation, the first corner section 120 and the second corner section 210 cooperate with each other, and the direction of the winding driving force has an included angle with both corner sections. Therefore, in the region where the two corner sections cooperate with each other, the winding driving force can provide a component force along the thickness direction of the two corner sections, so that the fit between the first corner section 120 and the second corner section 210 is more compact, thereby limiting the relative movement between the first corner section 120 and the second corner section 210 along the first direction, which is beneficial to ensuring the performance of the battery.

[0042] It should be noted that when the second pole piece 200 is wound to form the second corner section 210 at the winding start end, due to its rigidity and bending deformation during winding, a tension force will be generated towards the first corner section 120. As the winding proceeds, this tension force promotes the tight fit between the second corner section 210 and the first corner section 120, which not only increases the friction between the two corner sections and inhibits the relative movement between the first corner section 120 and the second corner section 210, but also improves the problem of local current density unevenness caused by poor fit between the first corner section 120 and the second corner section 210, thereby effectively improving the lithium precipitation phenomenon of the battery, which is beneficial to improving the performance and stability of the battery and prolonging the service life of the battery.

[0043] Reference Figure 2According to the winding core structure of the second embodiment of the present application, the first corner section 120 is provided with a first groove 121 on the side close to the second corner section 210, and at least a part of the second corner section 210 is located in the first groove 121. The first corner section 120 and the second corner section 210 are both curved sections, and the first corner section 120 and the second corner section 210 are curvedly fitted. On the one hand, during the winding operation, the extension direction of the first corner section 120 and the second corner section 210 can be arranged at an angle with the winding traction direction, so as to limit the relative movement between the first pole piece 100 and the second pole piece 200. On the other hand, at least a part of the second corner section 210 can be embedded in the first groove 121, further limiting the movement of the second corner section 210 relative to the first corner section 120 in the first direction, so that the winding core structure of the present application can effectively limit the relative movement of the first pole piece 100 and the second pole piece 200 in the first direction.

[0044] It should be noted that the second corner section 210 starts from the winding starting end of the second pole piece 200, and the first groove 121 can also balance the increased thickness of the second corner section 210 due to winding warping, avoid the local overthickness at the fitting position of the first corner section 120 and the second corner section 210, and improve the flatness of the winding core structure, and the battery performance including the winding core structure is better. Wherein, the first pole piece 100 is a cathode piece, and the second pole piece 200 is an anode piece.

[0045] Specifically, the first pole piece 100 includes a cathode active material layer, the cathode active material layer on the side of the first corner section 120 close to the second corner section 210 is thinned to form the first groove 121, and a part of the second corner section 210 is located in the first groove 121, so that a part of the second corner section 210 forms a stepped structure, which facilitates more effective restriction of the movement of the second corner section 210 relative to the first corner section 120. It should be understood that a part of the diaphragm 300 is located between the first corner section 120 and the second corner section 210, and therefore, a part of the diaphragm 300 is also located in the first groove 121.

[0046] Referring to Figures 2 to 6 In other embodiments, the depth of the first groove 121 is consistent with the thickness of the cathode active material layer on the side of the first corner section 120 close to the second corner section 210, that is, the cathode active material is completely removed in the partial region of the first corner section 120 to form the first groove 121. Therefore, the first pole piece 100 forms a deeper first groove 121 at the first corner section 120, and further, it is beneficial to further reduce the influence of the increased thickness of the second corner section 210 due to warping, so as to improve the flatness of the winding core structure.

[0047] It should be noted that in any embodiment of the present application, the first pole piece 100 and the second pole piece 200 each include a winding start end and a winding end, and the first direction should be understood as a direction from the winding start end of the first pole piece 100 to the winding end of the first pole piece 100, or alternatively, the first direction can also be understood as a direction from the winding start end of the second pole piece 200 to the winding end of the second pole piece 200. In addition, the first pole piece 100 and the second pole piece 200 each have two states of winding and unfolding, and in the unfolded state, the first direction is parallel to the length direction of the first pole piece 100 and the second pole piece 200 (see Figure 4 and Figure 5 ). In the winding state, the first direction has different directions at different positions of the cell body.

[0048] Referring to Figures 2 to 6 , in some embodiments, the first pole piece 100 is a cathode, the second pole piece 200 is an anode, the cathode active material layer of the first pole piece 100 has a first thickness, and the anode active material layer of the second pole piece 200 has a second thickness. The first thickness is in a range of 30 μm to 50 μm, for example, the first thickness can be any value in 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, and the second thickness is in a range of 40 μm to 70 μm, and the second thickness can be any value in 40 μm, 45 μm, 50 μm, 55 μm or 60 μm. The second thickness is greater than the first thickness, which can provide more sites for lithium ion insertion, reduce the accumulation of lithium ions on the surface of the second pole piece 200, and help to alleviate the lithium precipitation problem of the battery, improve the performance of the battery and prolong the service life.

[0049] Referring to Figures 2 to 6 , in some embodiments, one side of the first corner section 120 facing the second corner section 210 is coated with a cathode active material layer, and the cathode active material layer is provided with a first groove 121. The ratio of the depth of the first groove 121 to the thickness of the cathode active material layer is in a range of 0.1 to 1, that is, the single-layer cathode active material layer is thinned by 10% to 100% to form the first groove 121. For example, the above-mentioned ratio can be any value in 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1, or the above-mentioned ratio is an interval value with any two values in 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 as end point values. The lower limit of the ratio in the present embodiment is used to ensure the formation of the first groove 121, thereby ensuring the accommodation of the second corner section 210, and the upper limit of the ratio in the present embodiment is used to avoid the opening of the first groove 121 damaging the base layer (i.e. the current collector) of the first corner section 120.

[0050] Referring to Figures 2 to 6In some embodiments, the winding start end of the second pole piece 200 is located in the first groove 121, that is, the end of the second corner section 210 is located in the first groove 121, so that the second pole piece 200 can generate a step structure, which can abut against the first pole piece 100 when the second pole piece 200 has a tendency to generate relative movement, and more effectively limit the relative movement between the two.

[0051] With reference to Figures 2 to 6 In some embodiments, in the first direction, the length of the first groove 121 is 0.2mm to 3mm, for example, the length of the first groove 121 can be any value in 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm, or the length of the first groove 121 can also be an interval value with any two values in 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm as end point values, limiting the lower limit of the length of the first groove 121, balancing the increased thickness of the first corner section 120 due to warping, so that the winding core structure is more flat, limiting the upper limit of the length of the first groove 121, reducing the energy loss of the first pole piece 100, and being beneficial to guarantee the energy density of the winding core structure.

[0052] It should be noted that, in the first direction, the starting position of the first groove 121 is arranged close to the winding start end of the second corner section 210, so that in the thickness direction of the second pole piece 200, the local thickening area of the second corner section 210 due to warping is projected in the first groove 121, so as to alleviate the thickness of the second corner section 210 due to warping.

[0053] With reference to Figure 3 And Figure 4 According to the winding core structure of the third embodiment of the present application, the side of the first corner section 120 close to the second corner section 210 is provided with the first groove 121, and the fixed adhesive paper 400 is arranged in the first groove 121, and the fixed adhesive paper 400 is located between the first corner section 120 and the second corner section 210, so that the fixed adhesive paper 400 can fix the first corner section 120 and / or the second corner section 210, further limit the movement of the first corner section 120 and / or the second corner section 210, and be beneficial to guarantee the performance of the battery.

[0054] Specifically, the diaphragm 300 is arranged between the first corner section 120 and the second corner section 210, and the fixed adhesive paper 400 can be arranged between the first corner section 120 and the diaphragm 300, and the fixed adhesive paper 400 connects the first corner section 120 and the diaphragm 300, and is used to limit the movement of the first corner section 120 relative to the diaphragm 300.

[0055] Alternatively, the fixed adhesive paper 400 can be arranged between the second corner section 210 and the diaphragm 300, a part of the diaphragm 300 and the fixed adhesive paper 400 are located in the first groove 121, the fixed adhesive paper 400 connects the second corner section 210 and the diaphragm 300, and is used to limit the movement of the second corner section 210 relative to the diaphragm 300.

[0056] Alternatively, the fixed adhesive paper 400 is arranged between the first corner section 120 and the diaphragm 300, and the fixed adhesive paper 400 is arranged between the second corner section 210 and the diaphragm 300, the diaphragm 300 between the two fixed adhesive papers 400 is located in the first groove 121, the first corner section 120 and the diaphragm 300 are connected through the fixed adhesive paper 400, and the second corner section 210 and the diaphragm 300 are connected through the fixed adhesive paper 400, thereby limiting the relative movement between the first corner section 120 and the second corner section 210, and being beneficial to guarantee the performance of the battery.

[0057] Referring to Figure 3 and Figure 4 In other embodiments, the fixed adhesive paper 400 is an insulating adhesive paper, which is used to further block the conduction between the first corner section 120 and the second corner section 210. For example, the fixed adhesive paper 400 can be a hot melt adhesive.

[0058] Referring to Figures 3 to 5 In some embodiments, the side of the second corner section 210 away from the first corner section 120 is provided with an anode active material layer, and the anode active material layer is provided with a second groove 220, and the ratio of the depth of the second groove 220 to the thickness of the anode active material layer ranges from 0.1 to 1, that is, the single-layer anode active material layer is thinned by 10% to 100% to form the second groove 220. The lower limit of the ratio is used to guarantee the formation of the second groove 220, and the upper limit of the ratio is used to avoid the opening of the second groove 220 damaging the base layer (i.e. the current collector) of the second corner section 210. The opening of the second groove 220 can reduce the space occupation of the first corner section 120 and balance the increased thickness of the first corner section 120, which is beneficial to improve the energy density of the battery.

[0059] For example, the ratio of the depth of the second groove 220 to the thickness of the anode active material layer can be any one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1, or can also be an interval value with any two of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 as end point values. When the ratio is 1, that is, the anode active material layer is completely removed on the side of the second corner section 210 away from the first corner section 120.

[0060] And / or, the second corner section 210 is provided with an anode active material layer on the side facing the first corner section 120, the anode active material layer is provided with a third groove 230, the ratio of the depth of the third groove 230 to the thickness of the anode active material layer ranges from 0.1 to 1, and for the same reason, the third groove 230 can reduce the space occupation of the first corner section 120 and balance the increased thickness of the first corner section 120, which is beneficial to improve the energy density of the battery. In addition, the ratio of the depth of the third groove 230 to the thickness of the anode active material layer can refer to the ratio of the depth of the second groove 220 to the thickness of the anode active material layer.

[0061] Reference Figures 3 to 5 In other embodiments, the winding starting end of the separator 300 is located in the second groove 220, on the one hand, the second groove 220 can balance the increased thickness of the separator 300, and on the other hand, the winding starting end of the separator 300 is stacked in the second groove 220, which can limit the relative movement between the second corner section 210 and the separator 300.

[0062] Reference Figure 6 In some embodiments, the second corner section 210 is provided with a limiting groove 240 on the side facing the first corner section 120, and the first corner section 120 corresponds to the limiting groove 240. The corresponding of the two can be that the limiting groove 240 is set to increase the roughness of the surface of the second corner section 210, and the first corner section 120 covers the limiting groove 240 on the surface of the second corner section 210. It can also be that a part of the first corner section 120 is embedded in the limiting groove 240 and abuts the groove wall of the limiting groove 240, thereby limiting the movement of the second corner section 210 relative to the first corner section 120. Therefore, the setting of the limiting groove 240 can ensure the structural stability of the winding core structure, thereby being beneficial to ensure the performance of the winding core structure.

[0063] Reference Figures 1 to 6 In other embodiments, the second corner section 210 is provided with a limiting groove 240 on the side close to the first corner section 120, and the first corner section 120 is provided with a first groove 121 on the side close to the second corner section 210. The groove wall of the limiting groove 240 abuts the groove wall of the first groove 121 to limit the movement of the first corner section 120 relative to the second corner section 210. Through the cooperation of the two, it is beneficial to further limit the movement of the second pole piece 200 relative to the first pole piece 100 in the first direction.

[0064] Reference Figures 1 to 6In some embodiments, the length of the second corner section 210 in the first direction is 0 (not included) to 2 mm, for example, the length of the second corner section 210 can be any value in 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.7 mm and 2 mm, or the length of the second corner section 210 can also be an interval value with any two values in 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.7 mm and 2 mm as end point values, defining the lower limit of the length of the second corner section 210, for limiting the movement of the second corner section 210 relative to the first corner section 120 in the first direction during winding operation, and defining the upper limit of the length of the second corner section 210, for avoiding too large bending radius of the second corner section 210, so that the winding core structure is more compact.

[0065] With reference to Figures 1 to 6 In other embodiments, the winding starting end of the second corner section 210 projects into the first groove 121 in the thickness direction of the second corner section 210, and the length of the second corner section 210 in the first direction is less than the length of the first groove 121, so that the first groove 121 can reduce the thickness influence of the second corner section 210 due to warping within the length range of the second corner section 210, so that the winding core structure is more flat.

[0066] With reference to Figures 1 to 6 According to the battery of the embodiments of the present application, the battery includes a packaging film and the winding core structure in any of the above embodiments, the packaging film covers the winding core structure to realize packaging of the winding core structure, and the winding core structure ensures the flatness of the battery and is beneficial to ensuring the performance of the battery.

[0067] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A core structure, characterized by, The application relates to a battery core structure. The first pole piece comprises a first flat section starting from a winding starting end of the first pole piece and a first corner section connected with the first flat section, and the first flat section and the first corner section are arranged in sequence along a first direction. The second pole piece comprises a second corner section starting from a winding starting end of the second pole piece, at least one side of the second corner section is coated with an anode active material layer, and the edge of the anode active material layer is flush with the winding starting end of the second pole piece. The separator is arranged in layers with the first pole piece, the separator and the second pole piece, and the first pole piece, the separator and the second pole piece are wound to form a battery core body along the first direction. The winding starting end of the second pole piece is projected in the first corner section along the thickness direction of the second corner section.

2. The core structure of claim 1, wherein The first corner section is provided with a first groove on the side close to the second corner section, and at least a part of the second corner section is located in the first groove.

3. The core structure of claim 2, wherein The side of the first corner section facing the second corner section is coated with a cathode active material layer, the cathode active material layer is provided with the first groove, and the ratio of the depth of the first groove to the thickness of the cathode active material layer ranges from 0.1 to 1.

4. The core structure of claim 2, wherein The winding starting end of the second pole piece is located in the first groove.

5. The core structure of claim 2, wherein The length of the first groove along the first direction ranges from 0.2 mm to 3 mm.

6. The core structure of claim 1, wherein The first corner section is provided with a first groove on the side close to the second corner section, and a fixing adhesive paper is arranged in the first groove, and the fixing adhesive paper is located between the first corner section and the second corner section.

7. The core structure of claim 1, wherein The side of the second corner section away from the first corner section is provided with the anode active material layer, the anode active material layer is provided with a second groove, and the ratio of the depth of the second groove to the thickness of the anode active material layer ranges from 0.1 to 1. The side of the second corner section facing the first corner section is provided with the anode active material layer, the anode active material layer is provided with a third groove, and the ratio of the depth of the third groove to the thickness of the anode active material layer ranges from 0.1 to 1.

8. The core structure of claim 1, wherein The side of the second corner section facing the first corner section is provided with a limiting groove, and the first corner section is in close contact with the limiting groove.

9. The core structure according to any one of claims 1 to 8, characterized in that The length of the second corner section ranges from 0 to 2 mm.

10. A battery, characterized by The application further relates to a battery core structure. The application further relates to a battery core structure. ​

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