Battery cell and electric equipment using same

Abstract

The battery cell comprises a first pole piece and a second pole piece, the first pole piece and the second pole piece are alternately stacked, and an isolating membrane is arranged between the first pole piece and the second pole piece. The first pole piece comprises a first current collector and a first active material layer arranged on the surface of the first current collector. The second pole piece comprises a second current collector and a second active material layer arranged on the surface of the second current collector. The first pole piece further comprises a first concave part formed by missing the first active material layer, and a first tab arranged in the first concave part; and the second pole piece comprises a second concave part formed by missing the second active material layer. And the first concave part and the second concave part are oppositely arranged along the thickness direction of the battery cell. A first insulating layer is arranged on the surface of the first tab, and a first insulating occupying piece is arranged on the second concave part, so that the structural flatness and safety of the battery cell are improved.

Description

[0001] This application is a divisional application with application number 202180006747.6, application date September 30, 2021, and invention name “Battery cell and electrical equipment using the battery cell”. Technical Field

[0002] The present application relates to a battery cell and an electrical device using the battery cell. Background Art

[0003] Batteries have been widely used in various electronic products due to their high energy density, high operating voltage, long cycle life, environmental protection and safety. Therefore, the requirements for battery safety are getting higher and higher. In the battery cell, due to the setting of the tab, it is often easy to increase the thickness of the battery cell in the connection area between the tab and the pole piece, affecting the flatness of the overall structure of the battery cell, and thus affecting the safety of the battery cell. Summary of the invention

[0004] In view of the above situation, it is necessary to provide a battery cell that is beneficial to structural flatness and safety.

[0005] The present application provides a battery cell, comprising a first pole piece and a second pole piece alternately stacked, wherein a separation film is provided between the first pole piece and the second pole piece. The first pole piece comprises a first current collector and a first active material layer provided on the surface of the first current collector. The second pole piece comprises a second current collector and a second active material layer provided on the surface of the second current collector. The first pole piece further comprises a first recess formed by the absence of the first active material layer, and a first pole ear provided in the first recess. The second pole piece comprises a second recess formed by the absence of the second active material layer. Along the thickness direction of the battery cell, the first recess and the second recess are arranged opposite to each other. The surface of the first pole ear is provided with a first insulating layer; and the second recess is provided with a first insulating placeholder. By providing the first insulating placeholder in the second recess, it is beneficial to strengthen the strength and thickness of the second pole piece at the second recess, reduce the difference between the second pole piece at the second recess and other areas of the second pole piece when the battery cell is subjected to force (e.g., pressing), and thus reduce the influence on the consistency of the battery cell interface. The battery cell disclosed in the present application is conducive to reducing the overall thickness of the battery cell, thereby helping to reduce the impact of the setting of the first pole ear on the overall thickness of the battery cell, and helping to improve the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0006] According to an embodiment of the present application, the first recess and the second recess are arranged opposite to each other, which means that in the thickness direction of the battery cell, the projections of the first recess and the second recess at least partially overlap.

[0007] According to one embodiment of the present application, when forming the above-mentioned first recess and / or second recess, the corresponding active material layer is missing and can expose the surface of the current collector of the corresponding polarity to form the first recess and / or second recess. According to another embodiment of the present application, when forming the above-mentioned first recess and / or second recess, the corresponding active material layer is missing and other functional layers coated on the corresponding current collector, such as a primer layer, etc., can also be exposed. According to another embodiment of the present application, when forming the above-mentioned first recess and / or second recess, the corresponding active material layer may also be partially missing to form a first recess and / or second recess whose bottom surface is the corresponding active layer. Thus, those skilled in the art can select different recess formation methods according to different needs.

[0008] As a solution of the present application, along the thickness direction of the battery cell, the thickness of the first pole sheet at the first pole ear is h1. The area where the first active material layer is provided on both opposite surfaces of the first current collector in the first pole sheet is the first pole sheet main body area, and the average thickness of the first pole sheet main body area is h2, wherein h2>h1>h2 / 2, which is conducive to further improving the flatness of the battery cell structure and ensuring the strength of the first pole sheet corresponding to the first pole ear, thereby improving the safety of the battery cell.

[0009] As a solution of the present application, the first current collector includes a main area connected to the first recess and corresponding to the first pole piece main area, the first recess includes a bottom wall and a side wall connecting the bottom wall and the main area of ​​the first current collector, and the angle between the bottom wall and the side wall is an obtuse angle, so as to make full use of the area of ​​the first current collector, which is conducive to improving the flatness of the battery cell structure and the energy density of the battery cell. Among them, the area corresponding to the first current collector and the first pole piece main area is the main area, that is, the first active material layer is provided on the opposite surfaces of the first current collector in this area to form the first pole piece main area.

[0010] As a solution of the present application, the direction in which the first pole ear extends out of the first pole piece is defined as the length direction, and the direction perpendicular to the length direction and the thickness direction is defined as the width direction. Along the width direction, the first insulating layer is arranged beyond the first pole ear. Along the length direction, the first insulating layer is arranged beyond the end of the first recess where the first pole ear is arranged. This solution is conducive to reducing the risk of short circuit between the first pole ear and the second pole piece, and improving the safety of the battery cell.

[0011] As a solution of the present application, the orthographic projection of the second recess on the projection plane perpendicular to the thickness direction of the battery cell falls within the range of the orthographic projection of the first recess on the projection plane, which is beneficial to reduce the risk of lithium plating during use of the battery cell, thereby improving the safety of the battery cell.

[0012] As a solution of the present application, the second recess is provided with a first insulating spacer, and a second insulating layer is provided on the surface of the first insulating spacer. Along the width direction, the width of the first insulating layer is W t1 , the width of the second insulating layer is W t2 , where W t1 >W t2 , which is helpful to reduce the risk of lithium plating when the battery cell is in use. Along the length direction, the first insulating layer exceeds the second insulating layer, thereby reducing the risk of contact short circuit between the second recess and the first pole piece, which is helpful to improve the safety of the battery cell.

[0013] As a solution of the present application, a second gap is provided between the first insulating placeholder and the second active material layer, and the second gap is filled with the second insulating layer, which is beneficial to reducing the difference between the second pole piece at the second recess and other areas of the second pole piece caused by the battery cell when the battery cell is subjected to force (such as pressing), thereby reducing the impact on the consistency of the battery cell interface.

[0014] As a solution of the present application, along the thickness direction of the battery cell, the thickness of the first insulating placeholder is less than the thickness of the second active material layer, which is beneficial to improving the flatness of the battery cell structure.

[0015] As a solution of the present application, the width of the first recess is W r1 , the width of the second recess is W r2 , where W r2 >W r1 ; and along the width direction, the edge of the second recess exceeds the edge of the first recess.

[0016] As a solution of the present application, along the length direction, the edge of the first recess exceeds the edge of the second recess, which is beneficial to reducing the risk of lithium plating when the battery cell is in use.

[0017] As a solution of the present application, on a projection plane perpendicular to the thickness direction of the battery core, the orthographic projection of the second recess is located within the orthographic projection of the first insulating layer.

[0018] As a solution of the present application, the first insulating placeholder includes one of green glue and hot melt glue.

[0019] As a solution of the present application, the first insulating layer is provided on both surfaces of the first pole ear spaced apart along the thickness direction, which is beneficial to reducing the risk of short circuit between the first pole ear and the second pole piece and improving the safety of the battery cell.

[0020] As a solution of the present application, H2-H1≥0.02mm, so as to improve the flatness of the battery cell structure and thus improve the safety of the battery cell.

[0021] As a solution of the present application, along the thickness direction of the battery cell, the thickness of the battery cell at the first pole ear is H1, and the average thickness of the battery cell is H2, where H2≥H1. This is conducive to reducing the overall thickness of the battery cell, thereby helping to reduce the impact of the setting of the first pole ear on the overall thickness of the battery cell, and helping to improve the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0022] As a solution of the present application, both surfaces of the first current collector at the first recess are exposed, so as to form a first groove body and a second groove body on two opposite surfaces of the first pole piece, respectively.

[0023] As a solution of the present application, the first pole ear is arranged on the first slot body. The second recess includes a first alignment groove and a second alignment groove. The first alignment groove is arranged opposite to the first slot body, and the second alignment groove is arranged opposite to the second slot body, which is conducive to reducing the influence of the arrangement of the first pole ear on the overall thickness of the battery cell, and is conducive to improving the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0024] As a solution of the present application, the edges of the first alignment groove and the second alignment groove are staggered to increase the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface.

[0025] As a solution of the present application, the edges of the first trough body and the second trough body are staggered to increase the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface.

[0026] As a solution of the present application, the first alignment groove and the edge of the first groove body are staggered to increase the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface.

[0027] As a solution of the present application, the second pole piece further includes a third recess formed by the absence of the second active material layer. The battery cell also includes a second pole ear arranged in the third recess, wherein the two surfaces of the second pole ear are at the first pole piece corresponding to each other. The absence of the first active material layer to form a fourth recess is conducive to reducing the influence of the second pole ear on the overall thickness of the battery cell, and is conducive to improving the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0028] As a solution of the present application, a third insulating layer is provided on the surface of the second pole ear. A second insulating placeholder is provided on the fourth recess, and a fourth insulating layer is provided on the surface of the second insulating placeholder, and the fourth insulating layer exceeds the third insulating layer, which is conducive to reducing the risk of short circuit between the second pole ear and the first pole piece and improving the safety of the battery cell.

[0029] As a solution of the present application, the direction in which the first electrode tab extends out of the first electrode sheet is defined as the length direction, and the direction perpendicular to the length direction and the thickness direction is defined as the width direction. Along the width direction, the first active material layer is provided on both sides of the first recess.

[0030] As one solution of the present application, the first recess penetrates the first active material layer along the length direction.

[0031] As a solution of the present application, the direction in which the first pole ear extends out of the first pole sheet is defined as the length direction; along the length direction, the first active material layer is provided on the first side and the second side opposite to the first recess, which is beneficial to reducing the risk of glue overflow during the process of forming the first recess, and is also beneficial to strengthening the strength and thickness of the battery cell at this location.

[0032] As a solution of the present application, along the length direction, the first electrode tab extends from the first side of the first recess, and the width of the first active material layer provided on the first side is 2 mm to 4 mm.

[0033] As one solution of the present application, along the length direction, a width of the first active material layer provided on the first side is 3 mm.

[0034] As a solution of the present application, the battery cell is a wound battery cell, the first pole sheet includes a plurality of first pole tabs, and the plurality of first pole tabs are stacked along the thickness direction of the battery cell.

[0035] The present application also provides an electrical device, comprising a load and the battery cell as described above, wherein the battery cell is used to supply power to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1a It is a schematic structural diagram of a battery cell according to one embodiment of the present application.

[0037] Figure 1b This is a schematic structural diagram of the first pole piece according to one embodiment of the present application.

[0038] Figure 2 It is a schematic structural diagram of a battery cell according to another embodiment of the present application.

[0039] Figure 3It is a partial enlarged cross-sectional schematic diagram of a battery cell at III according to one embodiment of the present application.

[0040] Figure 4a It is a partial enlarged cross-sectional schematic diagram of a battery cell according to one embodiment of the present application along a plane perpendicular to the width direction.

[0041] Figure 4b It is a partial cross-sectional schematic diagram of a battery cell according to an embodiment of the present application without a tab along a plane perpendicular to the thickness direction.

[0042] Figure 5 It is a partial cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the width direction.

[0043] Figure 6 This is a schematic cross-sectional view of a battery cell according to another embodiment of the present application along a plane perpendicular to the thickness direction.

[0044] Figure 7 It is a partial cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the thickness direction.

[0045] Figure 8 It is a partial enlarged cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the length direction.

[0046] Fig. 9 It is a partial enlarged cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the length direction.

[0047] Fig.10 It is a partial enlarged cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the length direction.

[0048] Fig.11 It is a partial enlarged cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the width direction.

[0049] Fig.12 It is a schematic partial cross-sectional view of a battery cell according to another embodiment of the present application along a plane perpendicular to the length direction.

[0050] Fig.13 It is a partial enlarged cross-sectional schematic diagram of a battery cell according to another embodiment of the present application along a plane perpendicular to the length direction.

[0051] Fig.14 It is a partial enlarged schematic diagram of the battery cell at XIV according to one embodiment of the present application.

[0052] Fig.15 It is a schematic partial enlarged cross-sectional view of a plane perpendicular to the width direction of a battery cell according to another embodiment of the present application.

[0053] Fig.16 This is a schematic structural diagram of a battery cell according to another embodiment of the present application.

[0054] Fig.17 This is a schematic diagram of the structure of an electrical equipment according to one embodiment of the present application.

[0055] Main component symbols

[0056]

[0057]

[0058] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0059] The technical scheme in the embodiment of the present application is described clearly and in detail below. Obviously, the described embodiment is only a part of the embodiment of the present application, rather than all the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0060] Hereinafter, the embodiments of the present application will be described in detail. However, the present application can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments illustrated herein. Rather, these exemplary embodiments are provided so that the present application is thoroughly and in detail communicated to those skilled in the art.

[0061] In addition, for simplicity and clarity, in the accompanying drawings, the size or thickness of various components, layers may be amplified. Throughout the entire text, the same numerical value refers to the same element. As used herein, the term "and / or", "and / or" includes any and all combinations of one or more related enumerated items. In addition, it should be understood that when element A is referred to as "connecting" element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.

[0062] Further, the use of “may” when describing embodiments of the present application means “one or more embodiments of the present application”.

[0063] The technical terms used herein are for the purpose of describing specific embodiments and are not intended to limit the present application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It should be further understood that the term "comprising", when used in this specification, refers to the presence of narrated features, values, steps, operations, elements and / or components, but does not exclude the presence or increase of one or more other features, values, steps, operations, elements, components and / or combinations thereof.

[0064] Spatially related terms, such as "above" and the like, may be used herein for convenience of description to describe the relationship of one element or feature to another element (or elements) or feature (or features) as illustrated in the figure. It should be understood that in addition to the directions described in the figures, spatially related terms are intended to include different orientations of the device or apparatus in use or operation. For example, if the device in the figure is turned over, the elements described as "above" or "on" other elements or features will be oriented "below" or "below" the other elements or features. Therefore, the exemplary term "above" may include both above and below directions.

[0065] It should be understood that when an element or layer is referred to as being "on", "connected to", "coupled to", or "adjacent to" another element or layer, the element or layer may be "directly on", "directly coupled to", "directly connected to", "directly coupled to", or "directly adjacent to" another element or layer, or one or more intermediate elements or layers may be present. In addition, "connected", "connected", etc. may also mean "electrically connected", "electrically connected", etc. based on what they are used as will be understood by those skilled in the art. In addition, when an element, component, region, layer, and / or portion is referred to as being "between" two elements, components, regions, layers, and / or portions, it may be the only element, component, region, layer, and / or portion between the two elements, components, regions, layers, and / or portions, or one or more intermediate elements, components, regions, layers, and / or portions may also be present.

[0066] It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts herein, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below can be referred to as the second element, component, region, layer or part without departing from the teaching of the exemplary embodiment.

[0067] Some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments / implementations and features in the embodiments / implementations can be combined with each other.

[0068] See also Figure 1a and Figure 2 The battery cell 100 includes a first pole piece 10, a second pole piece 30 and an isolation film 50. The isolation film 50 is located between the first pole piece 10 and the second pole piece 30. Figure 1a The first pole piece 10, the isolation film 50 and the second pole piece 30 are stacked to form a stack, and the stack is wound to form a wound battery cell. The wound battery cell includes a straight portion 100a and a bent portion 100b connected to opposite ends of the straight portion 100a. The stacking direction of the first pole piece 10, the isolation film 50 and the second pole piece 30 corresponding to the straight portion 100a is defined as the thickness direction X of the battery cell, that is, the direction perpendicular to the main plane of the battery cell. Please refer to Figure 2 The first pole piece 10, the isolation film 50 and the second pole piece 30 can also be directly stacked to form a stacked body, thereby obtaining a stacked battery cell. In this case, the thickness direction X of the battery cell is the stacking direction of the first pole piece 10, the isolation film 50 and the second pole piece 30.

[0069] See also Figures 1a to 4b The first pole piece 10 includes a first current collector 11 and a first active material layer 13 disposed on the surface of the first current collector 11. The first pole piece 10 is also provided with a first recess 15 formed by the partial loss of the first active material layer 13, and the first pole piece 10 also includes a first pole tab 17 disposed in and connected to the first recess 15. In the present application, the direction in which the first pole tab 17 extends from the first current collector 11 is defined as the length direction Y, and the direction perpendicular to the thickness direction X and the length direction Y is defined as the width direction Z.

[0070] The second pole piece 30 includes a second current collector 31 and a second active material layer 33 disposed on the surface of the second current collector 31. The second pole piece 30 is further provided with a second recess 35 formed by a partial loss of the second active material layer 33.

[0071] Please refer to Figure 1a and Figure 2 Along the thickness direction X of the battery cell, the first recess 15 and the second recess 35 are arranged opposite to each other, and along the thickness direction X of the battery cell, the thickness of the battery cell corresponding to the first pole ear 17 is H1, and the average thickness of the battery cell is H2, wherein H2≥H1, which is conducive to reducing the overall thickness of the battery cell, and further conducive to reducing the influence of the setting of the first pole ear on the overall thickness of the battery cell, and is conducive to improving the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0072] Preferably, H2-H1≥0.02mm, so as to improve the flatness of the battery cell structure and thus improve the safety of the battery cell.

[0073] When the first pole piece 10 is a cathode pole piece, the second pole piece 30 is an anode pole piece. When the first pole piece 10 is an anode pole piece, the second pole piece 30 is a cathode pole piece. In the present application, the first pole piece 10 is a cathode pole piece and the second pole piece 30 is an anode pole piece as an example for further description.

[0074] See also Figure 3 , along the width direction Z, both sides of the first concave portion 15 are provided with the first active material layer 13. Along the length direction Y, at least one side of the first concave portion 15 is provided with the first active material layer 13. Figure 4a As shown, along the length direction Y, the first side 12a and the second side 12b opposite to the first recess 15 are both provided with a first active material layer 13. Among them, along the length direction Y, the first pole ear 17 extends from the first side 12a of the first recess 15, and the width of the first active material layer 13 provided on the first side 12a can be 2mm to 4mm. Preferably, along the length direction Y, the width of the first active material layer 13 provided on the first side 12a can be 3mm. The first active material layer 13 provided on the first side 12a along the length direction Y is conducive to reducing the risk of glue overflow during the process of forming the first recess 15. At the same time, when the second recess 35 and the corresponding area are filled with the second active material layer 33 or the glue layer and other materials, the first active material layer 13 on the side where the first pole ear 17 extends from the first recess 15 along the length direction Y is conducive to strengthening the strength and thickness of the battery cell 100 at this location.

[0075] In other embodiments, Figure 5 As shown, along the length direction Y, one side of the first recess 15 may be provided with the first active material layer 13 , and the other side may extend to the edge of the first current collector 11 .

[0076] In some further embodiments, see Figure 6 Along the length direction Y, the first recess 15 may also penetrate the first active material layer 13 .

[0077] See also Figure 1b and Figure 3, the area where the first active material layer 13 is provided on both opposite surfaces of the first current collector 11 in the first pole piece 10 is the first pole piece main area 101. In some embodiments, along the thickness direction X of the battery cell, the thickness of the first pole piece 10 corresponding to the first pole ear 17 is h1, and the average thickness of the first pole piece main area 101 is h2, wherein h1 and h2 can satisfy h2>h1>h2 / 2, which is conducive to further improving the flatness of the battery cell structure, while ensuring the strength of the first pole piece 10 corresponding to the first pole ear 17, thereby improving the safety of the battery cell. Among them, in some embodiments, 75 microns ≤ h2 ≤ 120 microns, 68 microns ≤ h1<120 microns.

[0078] The first current collector 11 includes a main area 111 connected to the first recess 15 and corresponding to the first pole sheet main area 101. In some embodiments, the first recess 15 may be recessed in a direction away from the first pole tab 17 connected to the first recess 15 compared to the main area 111 of the first current collector 11, so as to leave space for arranging the first pole tab 17, which is conducive to reducing the influence of the arrangement of the first pole tab 17 on the thickness of the battery cell at that location, thereby facilitating improving the flatness of the battery cell structure after the first pole tab 17 is arranged.

[0079] The first recess 15 includes a bottom wall 151 and a side wall 153 connecting the bottom wall 151 and the main area 111 of the first current collector 11. The first recess 15 and the space formed by the first recess 15 due to the lack of the first active material layer together constitute a receiving area for setting the first pole ear 17, thereby making full use of the space of the first pole sheet 10 in the thickness direction, reducing the risk of the first pole ear 17 exceeding the first pole sheet 10 in the thickness direction, and also reducing the risk of the burr of the cut section of the first current collector 11 exceeding the first pole sheet 10 in the thickness direction, thereby reducing the possibility of short circuit. The angle α between the bottom wall 151 and the side wall 153 is an obtuse angle, so as to make full use of the area of ​​the first current collector 11, which is conducive to improving the flatness of the battery structure while improving the energy density of the battery. In some embodiments, the first pole ear 17 is arranged on the bottom wall 151 and can be separated from the first active material layer 13 to form a first gap 18. The side wall 153 is exposed from the first gap 18, and the peripheral area of ​​the bottom wall 151 can also be exposed from the first gap 18.

[0080] Preferably, in some embodiments, 135°≤α<180°, so as to ensure that the first current collector 11 is not excessively concave, thereby ensuring that the burrs on the cut surface of the first current collector 11 do not penetrate the diaphragm from the thickness direction to cause an internal short circuit, while reducing the risk of the first current collector breaking during the welding process.

[0081] In some embodiments, please refer to Figure 3 and Figure 7, the battery cell 100 may further include a first insulating layer 21, which is disposed on the surface of the first pole ear 17. In the width direction Z, the first insulating layer 21 exceeds the first pole ear 17, that is, the edge of the first insulating layer 21 extends from the edge of the first pole ear 17, so that the first insulating layer 21 completely covers the first pole ear 17 in the width direction Z, which is beneficial to reduce the risk of short circuit between the first pole ear 17 and the second pole piece 30, thereby improving the safety of the battery cell. In the length direction Y, the first insulating layer 21 exceeds the end 171 of the first pole ear 17 disposed in the first recess 15, that is, the edge of the first insulating layer 21 extends from the end 171 of the first pole ear 17, so that the first insulating layer 21 completely covers the end 171 of the first pole ear 17 in the length direction Y, thereby further helping to reduce the risk of short circuit between the first pole ear 17 and the second pole piece 30, thereby improving the safety of the battery cell. In the width direction Z, the width of the first insulating layer 21 is W t1 In some embodiments, along the width direction Z, the width of the first insulating layer 21 extending beyond one side of the first electrode tab 17 may be greater than or equal to 0.5 mm and less than 15 mm.

[0082] The material of the first insulating layer 21 includes a glue layer.

[0083] In some embodiments, see Figure 7 The orthographic projection of the second recess 35 on the projection plane perpendicular to the thickness direction X of the battery cell can fall into the orthographic projection of the first recess 15 on the projection plane, which is beneficial to reduce the risk of lithium plating when the battery cell is in use.

[0084] See also Figure 3 The battery cell 100 may further include a first insulating placeholder 22, which is disposed in the second recess 35, thereby facilitating reinforcement of the strength and thickness of the second pole sheet 30 at the second recess 35, and reducing the difference between the second pole sheet 30 at the second recess 35 and other areas of the second pole sheet 30 when the battery cell is subjected to force (such as pressing), thereby reducing the impact on the consistency of the battery cell interface.

[0085] Along the thickness direction X of the battery cell, the thickness of the first insulating placeholder 22 is preferably less than the thickness of the second active material layer 33 surrounding the second recess 35 on the second current collector 31 on the same side, that is, the thickness of the first insulating placeholder 22 is less than the average thickness of the second active material layer 33 on the same side or the main thickness of the second active material layer 33 on the same side corresponding to the main area 111 of the first current collector 11, thereby facilitating the improvement of the flatness of the battery cell structure. In some embodiments, along the thickness direction X of the battery cell, the difference in thickness between the first insulating placeholder 22 and the second active material layer 33 surrounding the second recess 35 on the same side is greater than 0 and less than 70 microns.

[0086] The first insulating placeholder 22 may be, but is not limited to, an insulating colloid, such as green glue, hot melt glue, etc. When the first insulating placeholder 22 is hot melt glue, it is beneficial for the first insulating placeholder 22 to effectively fill the second recess 35 under heating, thereby facilitating the seamless connection between the first insulating placeholder 22 and the second active material layer 33, further reducing the difference between the second electrode sheet 30 at the second recess 35 and other areas of the second electrode sheet 30 when the battery cell is subjected to force (such as pressing), thereby reducing the impact on the consistency of the battery cell interface.

[0087] In some embodiments, Figure 8 As shown, the first insulating spacer 22 and the second active material layer 33 may also be spaced apart to form a second gap 36 .

[0088] See also Figure 3 and Figure 7 The battery cell 100 may further include a second insulating layer 23, which is disposed on the surface of the first insulating placeholder 22. Preferably, the second insulating layer 23 completely covers the first insulating placeholder 22. In the width direction Z, the width of the second insulating layer 23 is W. t2 , W t1 >W t2 , which helps reduce the risk of lithium plating when the battery is in use.

[0089] In some embodiments, the periphery of the second insulating layer 23 may also extend beyond the periphery of the first insulating placeholder 22 and cover a portion of the surface of the second active material layer 33 surrounding the second recess 35, thereby reducing the risk of contact short circuit between the second recess and the first pole piece 10, thereby facilitating the improvement of the safety of the battery cell. In some embodiments, the width of the second insulating layer 23 covering the surface of the second active material layer 33 located on one side of the second recess 35 is greater than 0 and less than 11.5 mm.

[0090] In some embodiments, Fig. 9 As shown, the second insulating layer 23 may also extend beyond the surface of the first insulating placeholder 22 and fill the second gap 36, so as to further reduce the difference between the second electrode sheet 30 at the second recess 35 and other areas of the second electrode sheet 30 when the battery cell is subjected to force (e.g., pressing), thereby reducing the impact on the consistency of the battery cell interface. At this time, the second insulating layer 23 may contain hot melt adhesive to fill the second gap 36 when the second insulating layer 23 is pressed on the second electrode sheet 30.

[0091] In some embodiments, see Fig.10 , along the width direction Z, the width of the first recess 15 is W r1 , the width of the second recess 35 is W r2 , where W can also be satisfied r2 >Wr1 . Further, along the width direction Z, the edge of the second recess 35 exceeds the edge of the first recess 15. At this time, in order to reduce the risk of lithium plating when the battery cell is in use, along the width direction Z, the edge of the first insulating layer 21 exceeds the edge of the second recess 35. And along the width direction Z, the edge of the first insulating placeholder 22 provided in the second recess 35 can exceed the edge of the first recess 15, thereby effectively reducing the risk of short circuit between the first pole ear 17 and the first recess 15 and the second recess 35, which is beneficial to improve the safety of the battery cell.

[0092] In some embodiments, along the width direction Z, the width L1 of the edge of the second recess 35 beyond the edge of the first recess 15 may satisfy: 0<L1<11.5mm. The width L2 of the edge of the first insulating layer 21 beyond the edge of the second recess 35 may satisfy: 1.5mm<L2<13mm. The width L3 of the edge of the first insulating placeholder 22 beyond the edge of the first recess 15 may satisfy: 0<L3<13mm.

[0093] In order to reduce the risk of lithium plating when the battery cell is in use, the edge of the first recess 15 may exceed the edge of the second recess 35 along the length direction Y. In some embodiments, along the length direction Y, the length by which the edge of the first recess 15 may exceed the edge of the second recess 35 may satisfy a length greater than 1.5 mm and less than the length of the first pole piece 10 along the length direction Y.

[0094] In some embodiments, see Fig.11 , along the length direction Y, the edge of the second recess 35 may also exceed the edge of the first recess 15. That is, the orthographic projection of the first recess 15 on the projection plane perpendicular to the thickness direction X of the battery cell may fall into the orthographic projection of the second recess 35 on the projection plane. At this time, in order to reduce the risk of lithium plating when the battery cell is in use, on the projection plane perpendicular to the thickness direction X of the battery cell, the orthographic projection of the second recess 35 is completely located in the orthographic projection of the first insulating layer 21. On the projection plane perpendicular to the thickness direction X of the battery cell, the orthographic projection line of the first recess 15 may be completely located in the orthographic projection of the first insulating placeholder 22 provided in the second recess 35, thereby further reducing the risk of short circuit caused by contact between the first pole ear 17 and the first recess 15 and the second recess 35, which is beneficial to improve the safety of the battery cell. At the same time, the second insulating layer 23 may be omitted at this time.

[0095] See also Figure 3 , the two opposite surfaces of the first current collector 11 at the first recess 15 are exposed, so as to form opposite first slots 15a and second slots 15b on opposite sides of the first pole piece 10. In this embodiment, the first pole tab 17 is disposed in the first slot 15a.

[0096] The first insulating layer 21 may be respectively disposed on two surfaces of the first electrode tab 17 spaced apart along the thickness direction X of the battery cell. Specifically, one first insulating layer 21 is disposed on the surface of the first electrode tab 17 away from the second tank body 15 b, and the other first insulating layer 21 covers the side of the second tank body 15 b away from the first tank body 15 a and covers part of the first active material layer 13.

[0097] See also Fig.12 The edge of the first slot body 15a can be staggered with the edge of the second slot body 15b, which is beneficial to avoid the gap around the first slot body 15a and the gap around the second slot body 15b from overlapping, increasing the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface. In some embodiments, the edge of the first slot body 15a can also overlap or partially stagger with the edge of the second slot body 15b.

[0098] In some embodiments, see Figure 3 and Fig.10 The second recess 35 includes a first alignment groove 35a and a second alignment groove 35b, wherein the first alignment groove 35a is disposed opposite to the first groove body 15a, and the second alignment groove 35b is disposed opposite to the second groove body 15b.

[0099] See also Fig.13 , the edge of the first alignment groove 35a can be staggered with the edge of the second alignment groove 35b, which is conducive to avoiding the overlap of the gap around the first alignment groove 35a and the gap around the second alignment groove 35b, increasing the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface. In some embodiments, the edge of the first alignment groove 35a can also overlap or partially stagger with the edge of the second alignment groove 35b.

[0100] The edge of the first alignment groove 35a can be staggered with the edge of the first groove body 15a, and the edge of the second alignment groove 35b can be staggered with the edge of the second groove body 15b, which is also beneficial to increase the strength and thickness of the weak area of ​​the battery cell, thereby reducing the impact on the consistency of the battery cell interface.

[0101] In some embodiments, see Figure 1a and Fig.14 The second pole piece 30 may further include a third recess 38 formed by a partial loss of the second active material layer 33. The second pole piece 30 may further include a second pole tab 37 disposed in the third recess 38 and connected thereto.

[0102] The surface of the second pole tab 37 may be provided with a third insulating layer 25. In the width direction Z, the third insulating layer 25 exceeds the second pole tab 37, that is, the edge of the third insulating layer 25 extends from the edge of the second pole tab 37, so that the third insulating layer 25 completely covers the second pole tab 37 in the width direction Z, thereby reducing the risk of short circuit between the second pole tab 37 and the first pole sheet 10 and improving the safety of the battery cell. Fig.15 Along the length direction Y, the third insulating layer 25 exceeds the end 371 of the second pole ear 37 provided in the third recess 38, that is, the edge of the third insulating layer 25 extends from the end 371 of the second pole ear 37, so that the third insulating layer 25 completely covers the end 371 of the second pole ear 37 in the length direction Y, thereby further helping to reduce the risk of short circuit between the second pole ear 37 and the first pole sheet 10, thereby improving the safety of the battery cell.

[0103] See also Fig.14 , along the thickness direction X of the battery cell, the first electrode sheet 10 corresponds to the area of ​​the third recess 38 or the second electrode tab 37, and the fourth recess 19 is formed due to the absence of the first active material layer 13. Along the thickness direction X of the battery cell, the fourth recess 19 and the third recess 38 are arranged opposite to each other.

[0104] The battery cell 100 may also include a second insulating placeholder 26 disposed in the fourth recess 19, which is beneficial to reinforce the strength and thickness of the first pole sheet 10 at the fourth recess 19, reduce the difference between the first pole sheet 10 at the fourth recess 19 and other areas of the first pole sheet 10 when the battery cell is subjected to force (such as pressing), and thereby reduce the impact on the consistency of the battery cell interface.

[0105] Along the thickness direction X of the battery cell, the thickness of the second insulating placeholder 26 is preferably smaller than the thickness of the first active material layer 13 surrounding the fourth recess 19 on the first current collector 11 , thereby facilitating the improvement of the flatness of the battery cell structure.

[0106] The second insulating placeholder 26 may be, but is not limited to, an insulating colloid, such as green glue, hot melt glue, etc. When the second insulating placeholder 26 is a hot melt glue, it is beneficial for the second insulating placeholder 26 to effectively fill the fourth recess 19 under heating, thereby facilitating the seamless connection between the second insulating placeholder 26 and the first active material layer 13, further reducing the difference between the first pole piece 10 at the fourth recess 19 and other areas of the first pole piece 10 when the battery cell is subjected to force (such as pressing), thereby reducing the impact on the consistency of the battery cell interface. In some embodiments, there may also be a gap between the second insulating placeholder 26 and the first active material layer 13.

[0107] The battery cell 100 may further include a fourth insulating layer 27, which is disposed on the surface of the second insulating placeholder 26. In some embodiments, the periphery of the fourth insulating layer 27 may also extend beyond the periphery of the second insulating placeholder 26 and cover a portion of the surface of the first active material layer 13 surrounding the fourth recess 19, thereby facilitating further reducing the risk of contact short circuit between the burrs on the second pole ear 37 and the first pole piece 10, thereby facilitating improving the safety of the battery cell. Preferably, on a projection plane perpendicular to the thickness direction X of the battery cell, the orthographic projection of the third insulating layer 25 is completely within the orthographic projection of the fourth insulating layer 27. In some embodiments, the width of the edge of the orthographic projection of the fourth insulating layer 27 beyond the edge of the third insulating layer 25 on the same side is greater than or equal to 1.5 mm.

[0108] In some embodiments, see Fig.16 When the battery cell 100 is a wound battery cell, the first pole sheet 10 may include a plurality of first pole tabs 17, and the plurality of first pole tabs 17 may be stacked along the thickness direction X of the battery cell. Similarly, the second pole sheet 30 may also include a plurality of second pole tabs 37, and the plurality of second pole tabs 37 may be stacked along the thickness direction X of the battery cell.

[0109] See also Fig.17 The battery cell 100 can be applied to an electric device 200, which can be, but is not limited to, an energy storage product or an electric vehicle, such as an electric toy, a car, a game device, a computer, etc. The electric device 200 also includes a load (not shown), and the battery cell 100 is used to supply power to the load.

[0110] In the battery cell 100 of the present application and the electrical equipment 200 using the above-mentioned battery cell 100, the first recess 15 and the second recess 35 are arranged opposite to each other along the thickness direction X of the battery cell, and along the thickness direction X of the battery cell, the thickness of the battery cell corresponding to the first pole ear 17 is H1, and the average thickness of the battery cell is H2, wherein H2≥H1, which is conducive to reducing the overall thickness of the battery cell, and further conducive to reducing the influence of the setting of the first pole ear on the overall thickness of the battery cell, and is conducive to improving the flatness of the battery cell structure, thereby improving the safety of the battery cell.

[0111] Thickness test method

[0112] Measurement of overall cell thickness

[0113] Measuring instrument: PPG soft pack battery thickness gauge

[0114] Testing process:

[0115] S1. Start the measuring tool and reset the meter to zero;

[0116] S2. Place the battery cell to be tested on the test bench and adjust it to a suitable measurement position;

[0117] S3. Read the stable value measured by the measuring instrument under appropriate pressure.

[0118] Measurement of local thickness of battery cells

[0119] Measuring instrument: Digital micrometer

[0120] Testing process:

[0121] S1. Return the meter to zero and rotate the sleeve to open the alloy measuring surface;

[0122] S2. Hold the non-measuring position of the battery body with your hand and raise the measuring position of the battery into between the alloy measuring surfaces;

[0123] S3. Rotate the sleeve until the alloy measuring surface is lightly in contact with the measuring position of the battery cell; then rotate the ratchet wheel 3 times to indicate that the battery cell is fully in contact with the measuring surface;

[0124] S4. Read the data on the LCD screen, which is the measurement position of the battery cell;

[0125] S5. Use the same method to measure the thickness at three locations H1 and H2, and record the average value.

[0126] In addition, for ordinary technicians in this field, various other corresponding changes and modifications can be made according to the technical concept of this application, and all these changes and modifications should fall within the protection scope of this application.

Claims

1. A battery cell, comprising a first pole piece and a second pole piece alternately stacked, a separator is provided between the first pole piece and the second pole piece, the first pole piece comprises a first current collector and a first active material layer arranged on the surface of the first current collector, the second pole piece comprises a second current collector and a second active material layer arranged on the surface of the second current collector, characterized in that: The first pole sheet also includes a first recess formed by the absence of the first active material layer, a first pole ear arranged in the first recess, and a first insulating layer, the first pole ear is electrically connected to the first current collector; the first insulating layer includes a glue layer, and the first insulating layer is bonded to the surface of the first pole ear; the direction in which the first pole ear extends out of the first pole sheet is the length direction of the battery cell, along the length direction, the first active material layer is provided on the first side and the second side opposite to the first recess, and the first insulating layer is bonded to the surface of the first active material layer on the first side and the second side.

2. The battery cell according to claim 1, characterized in that: Along the length direction, the first electrode tab extends from the first side, and the first active material layer disposed on the first side has a width of 2 mm to 4 mm.

3. The battery cell according to claim 1, characterized in that: Along the length direction, an edge of the first insulating layer exceeds an edge of the first active material layer on the first side.

4. The battery cell according to claim 1, characterized in that: The second pole piece includes a second concave portion formed by the loss of the second active material layer, and the bottom of the second concave portion is the surface of the second current collector; Along the thickness direction of the battery core, the first recess and the second recess are arranged opposite to each other; The second recess is provided with a first insulating placeholder, and the first insulating placeholder is provided on the surface of the second current collector at the bottom of the second recess.

5. The battery cell according to claim 4, characterized in that: A direction perpendicular to the thickness direction and the length direction is a width direction of the battery core. Along the width direction, the first insulating placeholder is located in the second recess.

6. The battery cell according to claim 5, characterized in that: Along the width direction, the first insulating spacer is spaced apart from the second recess to form a second gap.

7. The battery cell according to claim 4, characterized in that: Along the thickness direction, the thickness of the first insulating spacer is less than or equal to the thickness of the second active material layer.

8. The battery cell according to claim 4, characterized in that: Observed from the length direction of the battery core and along the thickness direction of the battery core, the first insulating placeholder covers the first electrode tab.

9. The battery cell according to claim 4, characterized in that: A second insulating layer is disposed on the surface of the first insulating placeholder, and the second insulating layer is also disposed on the surface of the second active material layer.

10. The battery cell according to claim 9, characterized in that: The direction perpendicular to the thickness direction and the length direction is the width direction of the battery cell. When viewed from the width direction, in the thickness direction, the second insulating layer covers at least a portion of the first active material layer on the first side.

11. The battery cell according to claim 9, characterized in that: A direction perpendicular to the thickness direction and the length direction is a width direction of the battery cell. When viewed from the width direction, in the length direction, an edge of the first insulating layer exceeds an edge of the second insulating layer.

12. The battery cell according to claim 4, characterized in that: The direction perpendicular to the thickness direction and the length direction is the width direction of the battery cell. When viewed from the width direction, in the length direction, the edge of the first recess exceeds the edge of the first insulating placeholder.

13. The battery cell according to claim 12, characterized in that: When viewed from the width direction, in the thickness direction, the first insulating placeholder covers the bottom of the first electrode tab.

14. The battery cell according to claim 4, characterized in that: The first insulating placeholder includes insulating colloid.

15. The battery cell according to claim 14, characterized in that: The insulating colloid includes adhesive tape or hot melt adhesive.

16. The battery cell according to claim 1, characterized in that: The direction perpendicular to the thickness direction and the length direction of the battery cell is the width direction of the battery cell. When viewed from the width direction, the second active material layer is not provided on the surface of the second current collector opposite to the first active material layer on the first side.

17. The battery cell according to claim 1, characterized in that: The first electrode tab is in contact with a surface of the first active material layer on the first side.

18. The battery cell according to claim 1, characterized in that: The first pole piece is a cathode pole piece, and the second pole piece is an anode pole piece.

19. An electrical equipment, characterized in that: The invention comprises a load and a battery cell as claimed in any one of claims 1 to 18, wherein the battery cell is used to supply power to the load.

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