Battery cell and battery
By setting up empty foil areas in the battery cell and optimizing the separator layout, the problem of lithium-ion transport resistance caused by the stacking of multiple separators was solved, achieving high-efficiency charging and discharging performance and extended service life of the battery.
Patent Information
- Application Number
- CN202520280605.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2035-02-21
AI Technical Summary
The stacking of multiple separators in the inner ring area of the battery cell increases the resistance to lithium-ion transport, affecting the battery's cycle performance and lifespan.
Design a cell structure in which an empty foil area is provided between the cathode and anode plates to reduce the stacking of separator layers, optimize the separator layout to avoid hindering lithium-ion transport, and set a single-layer separator between the active material layers to avoid short circuits, thereby improving the charge and discharge performance of the cell.
It improves the charge-discharge cycle performance of the battery cell, extends the battery's lifespan, and increases the cell's volumetric energy density and structural uniformity.
Smart Images
Figure CN223693181U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of batteries, in particular to a battery cell and a battery. BACKGROUND
[0002] In the battery production process, the battery cell is usually formed by stacking and winding an anode sheet, a separator and a cathode sheet. However, the inner ring region of the battery cell usually has a multi-layer separator stacking structure. The separator is used to isolate the direct contact between the anode sheet and the cathode sheet, thereby avoiding short circuit of the battery cell. However, the multi-layer separator will increase the transmission resistance of lithium ions, thereby causing the cycle performance of the battery to decrease and the service life of the battery to be short. 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 battery cell which can improve the charge-discharge cycle performance of the battery cell and is beneficial to prolong the service life of the battery cell.
[0004] The present application also provides a battery having the above battery cell.
[0005] The battery cell according to the embodiments of the present application comprises an anode sheet, a cathode sheet, a first separator and a second separator.
[0006] The anode sheet comprises an anode first flat section, and the anode first flat section comprises a winding starting end of the anode sheet.
[0007] The cathode sheet comprises a cathode first flat section, and the cathode first flat section comprises a winding starting end of the cathode sheet.
[0008] The first separator comprises a first flat section and a second flat section, the first flat section comprises a winding starting end of the first separator, and the first flat section and the second flat section are arranged in sequence and spaced apart along the winding direction of the battery cell.
[0009] The second separator comprises a third flat section, and the third flat section comprises a winding starting end of the second separator.
[0010] The first separator, the anode sheet, the second separator and the cathode sheet are arranged in layers along the first direction, the first flat section, the second flat section and the third flat section define a first layering region, the first layering region is located between the anode first flat section and the cathode first flat section, the cathode first flat section comprises a first empty foil region on the side close to the first layering region, and the projection of the first empty foil region in the first direction is located within the range of the first flat section.
[0011] According to the battery cell provided by the embodiment of the present application, at least the following beneficial effects are achieved: the first flat section, the second flat section and the third flat section are stacked to form a three-layer separator, and the first flat section of the cathode is provided with a first empty foil area, a projection of the first empty foil area in the first direction is located within a first stacking area defined by the three-layer separator, so that at least a part of the first stacking area can avoid hindering the transmission of lithium ions during the charging and discharging of the battery, thereby ensuring the charging and discharging performance of the battery cell and being beneficial to prolonging the service life of the battery cell. In addition, the provision of the first empty foil area can reduce the thickness of the first flat section of the cathode, thereby reducing the space occupation of the battery cell and being beneficial to improving the volume energy density of the battery cell.
[0012] According to some embodiments of the present application, the first flat section of the anode includes a second empty foil area on the side close to the first stacking area, and a projection of the second empty foil area in the first direction is located within the first empty foil area.
[0013] According to some embodiments of the present application, the winding starting end of the first separator is a first winding starting end, the winding starting end of the cathode sheet is a second winding starting end, the first flat section of the anode, the second flat section and the first flat section of the cathode stack to define a second stacking area along the first direction, the second stacking area is located between the first winding starting end and the second winding starting end along the second direction, and the first direction is perpendicular to the second direction.
[0014] In the second stacking area, the first flat section of the anode and the first flat section of the cathode are coated with active material on the side close to the second flat section.
[0015] According to some embodiments of the present application, in the second stacking area, the side of the first flat section of the anode facing the first flat section of the cathode is coated with a first active material layer, and the side of the first flat section of the cathode facing the first flat section of the anode is coated with a second active material layer, and the first active material layer and the second active material layer have the second flat section therebetween along the first direction.
[0016] In the second stacking area, the first flat section of the anode and the first flat section of the cathode are coated with active material on the side close to the second flat section.
[0017] According to some embodiments of the present application, the first active material layer covers the winding starting end of at least one of the first separator and the second separator along the first direction, and the projections of the first separator and the second separator in the first direction are both located outside the range of the second active material layer.
[0018] According to some embodiments of the present application, the cathode sheet further comprises a first corner section and a second cathode flat section, the anode sheet further comprises a second anode flat section, the anode first flat section and the second anode flat section are arranged in sequence along the winding direction of the battery cell, the first end of the first corner section is connected to the cathode first flat section, the second end of the first corner section is connected to the second cathode flat section, the anode first flat section is located between the cathode first flat section and the second cathode flat section, the second anode flat section is located on the side of the cathode first flat section away from the anode first flat section, the side of the anode first flat section facing the second cathode flat section is coated with a third active material layer, and the side of the second cathode flat section facing the anode first flat section is coated with a fourth active material layer;
[0019] wherein, along the first direction, the third active material layer projects on the second cathode flat section and covers the fourth active material layer.
[0020] According to some embodiments of the present application, the cathode sheet further comprises a first corner section, the first corner section is connected to the cathode first flat section, the first separator further comprises a second corner section, the second separator further comprises a third corner section, one end of the second corner section is connected to the first flat section, the other end of the second corner section is connected to the second flat section, the third corner section is connected to the third flat section, the third corner section is located between the first corner section and the second corner section, and the side of the first corner section facing the third corner section comprises a third empty foil area.
[0021] According to some embodiments of the present application, the side of the anode first flat section facing the cathode first flat section is coated with a first active material layer, the side of the cathode first flat section facing the anode first flat section is coated with a second active material layer, along the first direction, the first active material layer projects on the cathode first flat section and covers the second active material layer, along the winding direction of the battery cell, the first active material layer is arranged adjacent to the first empty foil area, and the length of the first active material layer exceeds the length of the second active material layer by 2mm to 5mm.
[0022] And / or, the cathode sheet comprises a second cathode flat section, the cathode first flat section and the second cathode flat section are arranged in sequence along the winding direction of the battery cell, the side of the anode first flat section facing the second cathode flat section is coated with a third active material layer, the side of the second cathode flat section facing the anode first flat section is coated with a fourth active material layer, along the first direction, the third active material layer projects on the second cathode flat section and covers the fourth active material layer, and the length of the third active material layer exceeds the length of the fourth active material layer by 2mm to 5mm.
[0023] According to some embodiments of the present application, the length of the first empty foil region ranges from 3mm to 85mm along the winding direction of the battery cell.
[0024] The battery according to the embodiments of the present application comprises the battery cell according to any of the above embodiments.
[0025] The battery according to the embodiments of the present application has at least the following beneficial effects: the battery according to the embodiments of the present application can improve the charge-discharge cycle performance and prolong the service life of the battery.
[0026] 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 learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS
[0027] The present application will be further described below in conjunction with the drawings and embodiments, wherein:
[0028] Figure 1 is a schematic view of the battery cell according to the embodiments of the present application;
[0029] Figure 2 is a schematic view of the battery cell according to the embodiments of the present application; Figure 2 is a partial enlarged view of A in FIG. 4;
[0030] Figure 3 is a schematic view of the battery cell according to another embodiment of the present application;
[0031] Figure 4 is a schematic view of the second layer stack region according to the embodiments of the present application;
[0032] Figure 5 is a partial schematic view of the battery cell according to another embodiment of the present application.
[0033] Reference signs: anode sheet 100, first flat section of anode 110, first active material layer 111, third active material layer 112, second flat section of anode 120, fourth corner section 130;
[0034] cathode sheet 200, first flat section of cathode 210, first corner section 220, second flat section of cathode 230, second active material layer 231, fourth active material layer 232;
[0035] first separator 300, first flat section 310, second flat section 320, second corner section 330;
[0036] second separator 400, third flat section 410, third corner section 420;
[0037] first layer stack region 510, second layer stack region 520. DETAILED DESCRIPTION
[0038] 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 meant to be included in at least one of the embodiments of the present application. The embodiments described below are examples only and are not intended to limit the present application in any way.
[0039] In the description of the present application, if the orientation description, such as up, down, front, back, left, right, etc. 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 purpose 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.
[0040] 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, etc. is understood as not including the number, above, below, etc. is 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.
[0041] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. 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.
[0042] 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 present specification, 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.
[0043] The embodiments of the present application are described below in conjunction with the accompanying drawings of the specification:
[0044] Reference Figures 1 to 4According to the electrode core, the electrode core is in a winding structure, and the electrode core comprises an anode sheet 100, a cathode sheet 200, a first diaphragm 300, and a second diaphragm 400. The anode sheet 100 comprises an anode first flat section 110, and the anode first flat section 110 comprises a winding starting end of the anode sheet 100. The cathode sheet 200 comprises a cathode first flat section 210, and the cathode first flat section 210 comprises a winding starting end of the cathode sheet 200. The first diaphragm 300 comprises a first flat section 310 and a second flat section 320. The first flat section 310 comprises a winding starting end of the first diaphragm 300. The first flat section 310 and the second flat section 320 are arranged in sequence and spaced apart along a winding direction of the electrode core. The second diaphragm 400 comprises a third flat section 410, and the third flat section 410 comprises a winding starting end of the second diaphragm 400. The first diaphragm 300, the anode sheet 100, the second diaphragm 400, and the cathode sheet 200 are arranged in a stack along a first direction, and the first direction is understood as a thickness direction of the electrode core.
[0045] The first flat section 310, the second flat section 320, and the third flat section 410 are arranged in a stack along the first direction to define a first stacking area 510. The first stacking area 510 is located between the anode first flat section 110 and the cathode first flat section 210. The side of the cathode first flat section 210 close to the first stacking area 510 comprises a first empty foil area. The projection of the first empty foil area along the first direction is located within the range of the cathode first flat section 210, so that the part covered by the projection of the first empty foil area in the first stacking area 510 can avoid hindering the transmission of lithium ions, that is, the part covered by the projection of the first empty foil area in the first stacking area 510 can avoid the lithium ion transmission path and avoid the transmission and migration of lithium ions through the three diaphragms. This is beneficial to guarantee the charge and discharge performance of the electrode core and prolong the service life of the electrode core.
[0046] In addition, compared with the scheme in which the opposite sides of the cathode first flat section 210 are coated with active substances, the first empty foil area is arranged in the present application. On the one hand, the cathode first flat section 210 is thinner, and the space occupation of the electrode core is reduced, which is beneficial to improve the energy density of the electrode core. On the other hand, the arrangement of the first empty foil area can also balance the increased thickness of the first flat section 310, the second flat section 320, and the third flat section 410 arranged in a stack, so that the thickness of the electrode core is more uniform, and the flatness of the electrode core is improved.
[0047] Reference Figures 1 to 4In some embodiments, along the first direction, the side of the anode first flat section 110 close to the first layering area 510 comprises a second empty foil area, the projection of the second empty foil area in the first direction is located in the first empty foil area, that is, the projection of the first empty foil area and the second empty foil area in the first direction has an overlapping area. Therefore, by blocking the first empty foil area and the second empty foil area through the three-layer separator, not only can the short circuit caused by the direct contact between the anode sheet 100 and the cathode sheet 200 be avoided, but also the migration path of lithium ions can be avoided, and the lithium ion migration between the anode active material and the cathode active material through the three-layer separator can be avoided, thereby ensuring the cycle performance of the battery cell.
[0048] It should be understood that, on the basis of the first empty foil area, the second empty foil area is arranged, which can reduce the thickness of the anode first flat section 110, so that the volume of the battery cell is further reduced, which is beneficial to improve the volume energy density of the battery cell.
[0049] Reference Figures 1 to 4 In other embodiments, along the first direction, the first empty foil area and the second empty foil area are both projected in the first layering area 510, the projection edge of the first empty foil area coincides with the edge of the first layering area 510, and the projection edge of the second empty foil area coincides with the edge of the first layering area 510, so that the projection size and shape of the first empty foil area, the second empty foil area and the first layering area 510 in the first direction are the same, and then, on the basis of avoiding the migration of lithium ions through the three-layer separator, the energy density of the battery cell can also be ensured.
[0050] Reference Figures 1 to 4 In some embodiments, the winding starting end of the first separator is a first winding starting end, the winding starting end of the cathode sheet is a second winding starting end, along the first direction, the anode first flat section 110, the second flat section 320 and the cathode first flat section 210 are layered to define a second layering area 520, along the second direction, the second layering area 520 is arranged adjacent to the first layering area 510, the second layering area 520 is located between the first winding starting end and the second winding starting end, and the first direction is perpendicular to the second direction. In the second layering area 520, the side of the anode first flat section 110 and the cathode first flat section 210 close to the second flat section 320 is coated with active material, on the one hand, the coated active material can balance the thickness difference caused by the layering of the first flat section 310, the second flat section 320 and the third flat section 410, so that the thickness of the battery cell is more uniform, on the other hand, in the second layering area 520, the active material on the side of the anode first flat section 110 and the cathode first flat section 210 facing each other further improves the energy density of the battery cell.
[0051] Specifically, the first flat section 310 and the third flat section 410 are located in the first stacking area 510, a part of the second flat section 320 is located in the first stacking area 510, another part of the second flat section 320 is located in the second stacking area 520, and the part of the second flat section 320 located in the second stacking area 520 is used to block the anode first flat section 110 and the cathode first flat section 210, that is, in the second stacking area 520, the anode sheet 100 and the cathode sheet 200 are only separated by a single layer of the separator. In the first stacking area 510, one side of the cathode first flat section 210 facing the second flat section 320 is a first empty foil area, and one side of the anode first flat section 110 facing the second flat section 320 is a second empty foil area. In the second stacking area 520, one side of the anode first flat section 110 facing the second flat section 320 is coated with an active material, and one side of the cathode first flat section 210 facing the second flat section 320 is coated with an active material. Therefore, without changing the stacking structure of the first flat section 310, the second flat section 320, and the third flat section 410, the energy density of the battery cell can be improved.
[0052] Reference Figures 1 to 4 In some embodiments, in the second stacking area 520, one side of the anode first flat section 110 facing the cathode first flat section 210 is coated with a first active material layer 111, and one side of the cathode first flat section 210 facing the anode first flat section 110 is coated with a second active material layer 231. In the first direction, the first active material layer 111 and the second active material layer 231 are separated by the second flat section 320, which is used to prevent direct contact between the first active material layer 111 and the second active material layer 231 to avoid short circuit of the battery cell. In the first direction, the first active material layer 111 projects on the cathode first flat section 210 and covers the second active material layer 231. Therefore, the first active material layer 111 can provide more reaction sites, which is beneficial to improve the lithium precipitation phenomenon of the battery cell, ensure the charge and discharge performance of the battery cell, and prolong the service life of the battery cell.
[0053] It should be understood that the first active material layer 111 and the second active material layer 231 are separated only by the second flat section 320. Specifically, the anode sheet 100 further includes an anode second flat section 120, which is arranged in sequence with the anode first flat section 110 along the winding direction of the battery cell, and the cathode first flat section 210 is located between the anode first flat section 110 and the anode second flat section 120 in the first direction.
[0054] Reference Figures 1 to 4In some embodiments, the first active material layer 111 has a thickness greater than that of the second active material layer 231, thereby providing more reaction sites for the second active material layer 231 to further improve the lithium precipitation phenomenon of the battery cell and further prolong the service life of the battery.
[0055] With reference to Figures 1 to 5 In some embodiments, based on the projection of the first active material layer 111 along the first direction covering the second active material layer 231, the first active material layer 111 covers the winding start end of at least one of the first separator 300 and the second separator 400 along the first direction, and the projections of the first separator 300 and the second separator 400 along the first direction are both located outside the range of the second active material layer 231, so that at least one of the first separator 300 and the second separator 400 can be arranged closer to the second active material layer 231 along the second direction (perpendicular to the first direction), so that the structure of the battery cell is more compact, which is beneficial to improve the energy density of the battery cell.
[0056] For example, the projection of the first active material layer 111 along the first direction includes a first part covering the second active material layer 231, and a second part extending beyond the edge of the second active material layer 231 along the second direction, the first separator 300 includes a winding start end, the second part covers at least a part of the winding start end of the first separator 300 along the first direction, and the winding start end of the first separator 300 is located outside the range of the first part, so that the winding start end of the first separator 300 can be arranged closer to the second active material layer 231, so that the structure of the battery cell is more compact, and the transmission of lithium ions between the first active material layer 111 and the second active material layer 231 can be avoided.
[0057] Alternatively, the second separator 400 includes a winding start end, the second part covers at least a part of the winding start end of the second separator 400 along the first direction, and the second separator 400 is located outside the range of the first part, so that the winding start end of the second separator 400 can be arranged closer to the second active material layer 231, so that the structure of the battery cell is more compact, and the transmission of lithium ions between the first active material layer 111 and the second active material layer 231 can be avoided.
[0058] Alternatively, the first and second separators 300 and 400 each include a winding start end, the second portion covers at least a part of the winding start ends of the first and second separators 300 and 400 in the first direction, and the first and second separators 300 and 400 are each located outside the range of the first portion, so that the first and second separators 300 and 400 can be arranged closer to the second active material layer 231, which is beneficial to improve the utilization rate of the inner ring area space of the battery cell and improve the energy density of the battery cell. In addition, the first and second separators 300 and 400 are each located outside the range of the first portion, which is used to avoid hindering the transmission of lithium ions between the first and second active material layers 111 and 231.
[0059] It should be noted that the first flat section 210 includes the winding start end of the first separator 300, and the third flat section 410 includes the winding start end of the second separator 400, so that the second portion covers the winding start end of the first separator 300 and / or the winding start end of the second separator 400. It should be understood that the second portion covers a part of the first flat section 210 and / or the third flat section 410.
[0060] Reference Figures 1 to 4 In some embodiments, the cathode sheet 200 further includes a first corner section 220, which is connected to the cathode first flat section 210 at a first connection. In the first direction, the anode first flat section 110 projects on the cathode sheet 200, and in the second direction, the projection of the anode first flat section 110 is 0-5 mm away from the first connection, and the first direction is perpendicular to the second direction. For example, the distance between the two can be any value of 0, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, so that the anode first flat section 110 is closer to the first corner section 220. On the one hand, it ensures that the anode first flat section 110 covers the first layer stack area 510 in the first direction, so that the battery cell is more compact. On the other hand, the side of the anode first flat section 110 away from the first layer stack area 510 can also be opposite to the active material on the surface of the cathode sheet 200, which is beneficial to improve the energy density of the battery cell.
[0061] It should be noted that the winding start end of the first diaphragm 300 is a first winding start end, and the first stacking area 510 is located between the first winding start end and the first connection in the second direction, so that the projection of the anode first flat section 110 in the first direction covers at least part of the first stacking area 510, the part of the first stacking area 510 covered by the projection of the anode first flat section 110 in the first direction has a thickness which is the sum of the thicknesses of the anode first flat section 110 and the first stacking area 510. The part of the first stacking area 510 not covered by the projection of the anode first flat section 110 in the first direction has a thickness which is the thickness of the first stacking area 510, so that the anode first flat section 110 is closer to the first corner section 220 in the second direction, facilitating the projection of the anode first flat section 110 in the first direction to more thoroughly cover the first stacking area 510, so that the thicknesses of different parts of the battery cell tend to be more uniform.
[0062] Reference Figures 1 to 4 In some embodiments, the cathode sheet 200 further comprises a first corner section 220 and a cathode second flat section 230, and the anode sheet 100 further comprises an anode second flat section 120, which are arranged in sequence in the winding direction of the battery cell, and in the first direction, one end of the first corner section 220 is connected to the cathode first flat section 210, the other end of the first corner section 220 is connected to the cathode second flat section 230, the anode first flat section 110 is located between the cathode first flat section 210 and the cathode second flat section 230, the anode second flat section 120 is located on the side of the cathode first flat section 210 away from the anode first flat section 110, the side of the anode first flat section 110 facing the cathode second flat section 230 is coated with a third active material layer 112, and the side of the cathode second flat section 230 facing the anode first flat section 110 is coated with a fourth active material layer 232. In the first direction, the third active material layer 112 projects on the cathode second flat section 230 and covers the fourth active material layer 232, the third active material layer 112 can provide more reaction sites, which helps to improve the lithium precipitation phenomenon of the battery cell, thereby prolonging the service life of the battery cell.
[0063] Reference Figures 1 to 4 In other embodiments, the thickness of the third active material layer 112 is greater than the thickness of the fourth active material layer 232, so as to further provide more reaction sites for the third active material layer 112, facilitate more effective improvement of the lithium precipitation phenomenon of the battery cell, and further prolong the service life of the battery.
[0064] Reference Figures 1 to 4In some embodiments, the cathode sheet 200 further comprises a first corner section 220 connected with the first flat section 210 of the cathode, the first separator 300 further comprises a second corner section 330, the second separator 400 further comprises a third corner section 420, one end of the second corner section 330 is connected with the first flat section 310, the other end of the second corner section 330 is connected with the second flat section 320, the third corner section 420 is connected with the third flat section 410, the third corner section 420 is located between the first corner section 220 and the second corner section 330, and the side of the first corner section 220 facing the third corner section 420 comprises a third empty foil area, which is beneficial to fully utilize the internal space of the battery cell and improve the energy density of the battery cell, and meanwhile, the thickness generated by the lamination of the second corner section 330 and the third corner section 420 can be balanced, thereby avoiding the over-thickness of the corner of the battery cell.
[0065] Specifically, along the first direction, the second corner section 330 and the third corner section 420 are laminated, so that on the side of the first corner section 220 close to the third corner section 420, the second corner section 330 and the third corner section 420 are laminated to form four layers of separators, and the third empty foil area can reduce the thickness of the first corner section 220, thereby effectively reducing the thickness impact generated by the lamination of the four layers of separators, so that the thickness of the battery cell is more uniform.
[0066] Reference Figures 1 to 4 In some embodiments, the anode sheet 100 further comprises a fourth corner section 130 connected with the first flat section 110 of the anode at a second connection, along the first direction, the first flat section 210 of the cathode is projected on the anode sheet 100, and along the second direction, the distance between the projection of the first flat section 210 of the cathode and the second connection is 0-5 mm, the first direction is perpendicular to the second direction, for example, the distance between the two can be any value of 0, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, so that the first flat section 210 of the cathode is closer to the fourth corner section 130, the structure of the battery cell is more compact, and it is beneficial to improve the energy density of the battery cell.
[0067] Reference Figure 3 And Figure 4 In some embodiments, the side of the first flat section 110 of the anode facing the first flat section 210 of the cathode is coated with a first active material layer 111, the side of the first flat section 210 of the cathode facing the first flat section 110 of the anode is coated with a second active material layer 231, along the first direction, the first active material layer 111 is projected on the first flat section 210 of the cathode and covers the second active material layer 231, and along the winding direction of the battery cell, the first active material layer 111 is arranged adjacent to the first empty foil area, and the length of the first active material layer 111 exceeds the length of the second active material layer 231 by 2-5 mm, which is beneficial to improve the lithium precipitation problem and prolong the service life of the battery cell.
[0068] For example, the length of the first active material layer 111 exceeds the length of the second active material layer 231 by a value of 2 mm, 3 mm, 4 mm, 5 mm, or any other value in the range of 2 mm to 5 mm, or the length of the first empty foil region can be an interval value with any two values in 2 mm, 3 mm, 4 mm, 5 mm as end point values.
[0069] Reference Figures 2 to 4 For example, the length of the third active material layer 112 exceeds the length of the fourth active material layer 232 by a value of 2 mm, 3 mm, 4 mm, 5 mm, or any other value in the range of 2 mm to 5 mm, or the length of the first empty foil region can be an interval value with any two values in 2 mm, 3 mm, 4 mm, 5 mm as end point values.
[0070] For example, the length of the third active material layer 112 exceeds the length of the fourth active material layer 232 by a value of 2 mm, 3 mm, 4 mm, 5 mm, or any other value in the range of 2 mm to 5 mm, or the length of the first empty foil region can be an interval value with any two values in 2 mm, 3 mm, 4 mm, 5 mm as end point values.
[0071] Reference Figures 1 to 3 For example, the length of the first empty foil region ranges from 3 mm to 85 mm in the winding direction of the battery cell, such as 3 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, or any other value in the range of 3 mm to 85 mm, or the length of the first empty foil region can be an interval value with any two values in 3 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm as end point values, which is beneficial to further optimize the structure of the battery cell to avoid cycling in the first layer stack region 510 with three stacked separators, and is beneficial to prolong the service life of the battery cell.
[0072] Reference Figures 1 to 5According to the battery of the embodiment of the application, the battery includes the battery cell in any of the above embodiments, and the battery of the application includes but is not limited to a soft package battery, a steel shell battery and the like, and the battery cell in the above embodiment is used, which is beneficial to improve the charge-discharge cycle performance of the battery and prolong the service life of the battery.
[0073] The above describes the embodiments of the application in detail in combination with the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge range of the ordinary skill in the art without departing from the purpose of the application. In addition, the embodiments of the application and the features in the embodiments can be combined with each other without conflict.
Claims
1. A battery cell, characterized in that, The battery cell has a wound structure, and the battery cell includes: An anode sheet, including a first straight section of the anode, wherein the first straight section of the anode includes the winding start end of the anode sheet; A cathode sheet, including a first straight section of the cathode, wherein the first straight section of the cathode includes the winding start end of the cathode sheet; The first diaphragm includes a first straight section and a second straight section. The first straight section includes the winding start end of the first diaphragm. Along the winding direction of the battery cell, the first straight section and the second straight section are arranged alternately. The second diaphragm includes a third straight section, the third straight section including the winding start end of the second diaphragm; Wherein, along a first direction, the first diaphragm, the anode sheet, the second diaphragm, and the cathode sheet are stacked, and the first straight section, the second straight section, and the third straight section are stacked to define a first stacked region. The first stacked region is located between the first straight section of the anode and the first straight section of the cathode. The side of the first straight section of the cathode near the first stacked region includes a first empty foil region, and the projection of the first empty foil region along the first direction is located within the range of the first straight section.
2. The battery cell according to claim 1, characterized in that, The first straight section of the anode includes a second empty foil area on the side near the first stacked area, and the projection of the second empty foil area along the first direction is located within the first empty foil area.
3. The battery cell according to claim 1, characterized in that, The first winding start end of the first diaphragm is the first winding start end, and the winding start end of the cathode sheet is the second winding start end. Along the first direction, the first straight section of the anode, the second straight section, and the first straight section of the cathode are stacked to define a second stacked area. Along the second direction, the second stacked area is located between the first winding start end and the second winding start end. The first direction is perpendicular to the second direction. In the second stacked region, the first straight section of the anode and the first straight section of the cathode are both coated with an active material on the side closest to the second straight section.
4. The battery cell according to claim 3, characterized in that, In the second stacked region, a first active material layer is coated on the side of the first straight section of the anode facing the first straight section of the cathode, and a second active material layer is coated on the side of the first straight section of the cathode facing the first straight section of the anode. Along the first direction, there is a second straight section between the first active material layer and the second active material layer. Along the first direction, the first active material layer is projected onto the first straight section of the cathode and covers the second active material layer.
5. The battery cell according to claim 4, characterized in that, Along the first direction, the first active material layer covers the winding start end of at least one of the first diaphragm and the second diaphragm, and the projections of the first diaphragm and the second diaphragm along the first direction are both located outside the range of the second active material layer.
6. The battery cell according to claim 1, characterized in that, The cathode sheet further includes a first corner section and a second straight cathode section, and the anode sheet further includes a second straight anode section. Along the winding direction of the battery cell, the first straight anode section and the second straight anode section are arranged sequentially. Along the first direction, one end of the first corner section is connected to the first straight cathode section, and the other end of the first corner section is connected to the second straight cathode section. The first straight anode section is located between the first straight cathode section and the second straight cathode section. The second straight anode section is located on the side of the first straight cathode section away from the first straight anode section. The side of the first straight anode section facing the second straight cathode section is coated with a third active material layer, and the side of the second straight cathode section facing the first straight anode section is coated with a fourth active material layer. Along the first direction, the third active material layer is projected onto the second straight section of the cathode and covers the fourth active material layer.
7. The battery cell according to claim 1, characterized in that, The cathode sheet further includes a first corner segment connected to a first straight segment of the cathode. The first diaphragm further includes a second corner segment, and the second diaphragm further includes a third corner segment. One end of the second corner segment is connected to the first straight segment, and the other end of the second corner segment is connected to the second straight segment. The third corner segment is connected to the third straight segment and is located between the first corner segment and the second corner segment. The side of the first corner segment facing the third corner segment includes a third empty foil area.
8. The battery cell according to claim 1, characterized in that, The first straight section of the anode is coated with a first active material layer on the side facing the first straight section of the cathode, and the first straight section of the cathode is coated with a second active material layer on the side facing the first straight section of the anode. Along the first direction, the first active material layer is projected onto the first straight section of the cathode and covers the second active material layer. Along the winding direction of the battery cell, the first active material layer is arranged adjacent to the first empty foil area, and the length of the first active material layer exceeds the length of the second active material layer by 2 mm to 5 mm. And / or, the cathode sheet includes a second flat cathode section. Along the winding direction of the battery cell, the first flat cathode section and the second flat cathode section are arranged sequentially. The side of the first flat cathode section facing the second flat cathode section is coated with a third active material layer, and the side of the second flat cathode section facing the first flat anode section is coated with a fourth active material layer. Along the first direction, the third active material layer is projected onto the second flat cathode section and covers the fourth active material layer. The length of the third active material layer exceeds the length of the fourth active material layer by 2 mm to 5 mm.
9. The battery cell according to any one of claims 1 to 8, characterized in that, Along the winding direction of the battery cell, the length of the first empty foil area ranges from 3 mm to 85 mm.
10. A battery, characterized in that, The battery cell includes any one of claims 1 to 9.