Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment. The battery cell comprises an electrode assembly, a first shell and a second shell, the electrode assembly comprises a first pole piece set and a second pole piece set which are arranged in a stacked mode in the first direction, and the length of the first pole piece set is larger than that of the second pole piece set in the second direction. In the first direction, the surface, facing the second shell, of the first shell is provided with a first containing cavity for containing the first pole piece set, the surface, facing the first shell, of the second shell is provided with a second containing cavity for containing the second pole piece set, and the depth of the first containing cavity and the depth of the second containing cavity are small, so that the machining difficulty is small; the matching degree with the outline of the electrode assembly is higher, the risk of shaking of the electrode assembly in the space formed by the first accommodating cavity and the second accommodating cavity is reduced or the shaking degree is reduced, the problem of falling failure is relieved, the space waste of the first accommodating cavity and the second accommodating cavity is reduced, and the energy density of the battery cell is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell and an electrical device. Background Art

[0002] With the rapid development of new energy technologies, battery cells have been widely used in electronic equipment, electric vehicles, electric two-wheeled vehicles, power tools, etc. As the application of battery cells becomes more and more extensive, higher requirements are placed on the safety of battery cells. Summary of the invention

[0003] The embodiments of the present application provide a battery cell and an electrical device to improve the safety performance of the battery cell.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, which includes an electrode assembly, a first shell and a second shell; the electrode assembly includes a first pole piece group and a second pole piece group, the first pole piece group and the second pole piece group are stacked along a first direction, along the second direction, the length of the first pole piece group is greater than the length of the second pole piece group, and the second direction is perpendicular to the first direction; the first shell and the second shell are arranged opposite to each other along the first direction, a first accommodating cavity is provided on a surface of the first shell facing the second shell, and a second accommodating cavity is provided on a surface of the second shell facing the first shell, along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity, along the first direction, at least a portion of the first pole piece group is accommodated in the first accommodating cavity, and at least a portion of the second pole piece group is accommodated in the second accommodating cavity.

[0005] In one or more of the above optional embodiments, a first accommodating cavity is provided on the surface of the first shell facing the second shell, and a second accommodating cavity is provided on the surface of the second shell facing the first shell. Along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity. Along the first direction, at least part of the first electrode group is accommodated in the first accommodating cavity, and at least part of the second electrode group is accommodated in the second accommodating cavity. Compared with the scheme in which a chamber whose depth along the first direction is the sum of the depths of the first accommodating cavity and the second accommodating cavity is formed only in the first shell, and compared with the scheme in which a chamber whose depth along the first direction is the sum of the depths of the first accommodating cavity and the second accommodating cavity is formed only in the second shell, in this scheme, the depths of the first accommodating cavity of the first shell and the second accommodating cavity of the second shell are both smaller, the processing difficulty is smaller, and the space formed by the first accommodating cavity and the second accommodating cavity has a higher matching degree with the contour of the electrode assembly. The first shell and the second shell can better restrain the first electrode group and the second electrode group, reduce the risk of the electrode assembly shaking in the space formed by the first accommodating cavity and the second accommodating cavity or reduce the degree of shaking, alleviate the problem of drop failure, thereby improving the impact resistance and stability of the battery cell when it is dropped. In addition, the first accommodating cavity of the present solution can better match the contour of the first pole piece group, and the second accommodating cavity can better match the contour of the second pole piece group. Therefore, the gap between the first pole piece group and the cavity wall of the first accommodating cavity is smaller, and the gap between the second pole piece group and the cavity wall of the second accommodating cavity is smaller, thereby reducing the space waste of the first accommodating cavity and the second accommodating cavity, which is beneficial to improving the energy density of the battery cell.

[0006] In some embodiments of the first aspect of the present application, along the first direction, a first protrusion is formed on the surface of the first shell facing away from the second shell at a position corresponding to the first accommodating cavity; and / or a second protrusion is formed on the surface of the second shell facing away from the first shell at a position corresponding to the second accommodating cavity.

[0007] In one or more of the above optional embodiments, a first protrusion is formed on the surface of the first shell away from the second shell in the first direction at a position corresponding to the first accommodating cavity, which is conducive to reducing the thickness difference between the parts of the first shell and improving the strength of the first shell. A second protrusion is formed on the surface of the second shell away from the first shell at a position corresponding to the second accommodating cavity, which is conducive to reducing the thickness difference between the parts of the second shell and improving the strength of the second shell. A first protrusion is formed on the surface of the first shell away from the second shell at a position corresponding to the first accommodating cavity, and a second protrusion is formed on the surface of the second shell away from the first shell at a position corresponding to the second accommodating cavity, so that the outer contour of the first shell and the outer contour of the second shell can better adapt to the special-shaped installation space, which is conducive to reducing the volume of the electrical equipment powered by the power supply.

[0008] In some embodiments of the first aspect of the present application, a portion of an edge of the first shell is connected to a portion of an edge of the second shell via a bending portion, and the first shell and the second shell are both integrally formed with the bending portion.

[0009] In one or more of the above optional embodiments, the first shell and the second shell are integrally formed with the bent portion, so the first shell and the second shell do not need to be sealed at the corresponding position of the bent portion or the sealing level can be reduced, which is conducive to simplifying the packaging process of the battery cell and reducing the difficulty of the battery cell. The first shell and the second shell are integrally formed with the bent portion, which can also reduce the weak connection parts of the battery cell packaging, which is conducive to the battery cell packaging having better strength and improving the safety performance and reliability of the battery cell.

[0010] In some embodiments of the first aspect of the present application, the edge of the first shell includes multiple first edge portions, the edge of the second shell includes multiple second edge portions, and a first edge portion among the multiple first edge portions and a second edge portion among the multiple second edge portions are connected by a bending portion.

[0011] In one or more of the above optional embodiments, a first edge portion among a plurality of first edge portions and a second edge portion among a plurality of second edge portions are connected through a bending portion, which is beneficial to simplifying the packaging process of the battery cell and reducing the packaging difficulty, and is also beneficial to reserving a larger entrance for the electrode assembly to enter the shell before the first shell and the second shell are packaged, so as to facilitate the placement of the electrode assembly into the space between the first shell and the second shell, reduce the difficulty of the electrode assembly entering the shell and improve the efficiency of shell entry.

[0012] In some embodiments of the first aspect of the present application, the first shell and the second shell are separately provided and connected.

[0013] In one or more of the above optional embodiments, the first shell and the second shell are separately arranged and connected to facilitate the matching of the first shell and the second shell with electrode assemblies of different sizes in the first direction, thereby making the packaging formed by the first shell and the second shell more versatile.

[0014] In some embodiments of the first aspect of the present application, the first accommodating cavity forms a first opening on the surface of the first shell facing the second shell, and the second accommodating cavity forms a second opening on the surface of the second shell facing the first shell. Along the second direction, one end of the first opening is flush with one end of the second opening, and the first opening extends beyond the other end of the second opening.

[0015] In one or more optional embodiments above, along the second direction, one end of the first opening is flush with one end of the second opening, which can provide positioning for the first pole piece group and the second pole piece group when the electrode assembly is placed in the shell, and can also standardize the structure of the electrode assembly, making it easier for the electrode assembly to be placed in the shell. The first opening exceeds the other end of the second opening, so that the size of the first accommodating cavity in the second direction can match the first pole piece group, and the size of the second accommodating cavity in the second direction can match the second pole piece group, thereby making it easier for the electrode assembly to be placed in the shell.

[0016] In some embodiments of the first aspect of the present application, the first accommodating cavity forms a first opening on the surface of the first shell facing the second shell, and the second accommodating cavity forms a second opening on the surface of the second shell facing the first shell, and along the third direction, two ends of the first opening are respectively flush with two ends of the second opening, and the first direction, the second direction and the third direction are perpendicular to each other.

[0017] In one or more of the above optional embodiments, along the third direction, the two ends of the first opening are flush with the two ends of the second opening, which facilitates the electrode assembly to enter the shell and the first electrode plate group and the second electrode plate group to match the first accommodating cavity and the second accommodating cavity respectively. It can also standardize the structure of the electrode assembly in the third direction and reduce the risk of the electrode plate moving along the third direction.

[0018] In some embodiments of the first aspect of the present application, the first shell includes a first sealing portion surrounding the first accommodating cavity, the second shell includes a second sealing portion surrounding the second accommodating cavity, and the first sealing portion and the second sealing portion are sealingly connected.

[0019] In one or more of the above optional embodiments, the first shell and the second shell are sealed and connected via the first sealing portion and the second sealing portion, thereby improving the sealing performance of the battery cell, thereby facilitating improving the safety performance of the battery cell.

[0020] In some embodiments of the first aspect of the present application, the first accommodating cavity is stamped and formed in the first shell, and the second accommodating cavity is stamped and formed in the second shell.

[0021] In one or more of the above optional embodiments, the first accommodating cavity and the second accommodating cavity are respectively formed in the first shell and the second shell by stamping. The first accommodating cavity and the second accommodating cavity are easy to form and have high dimensional accuracy, so that the first accommodating cavity and the second accommodating cavity can better match the first pole piece group and the second pole piece group, alleviate the problem of shaking of the electrode assembly, thereby alleviating the problem of falling failure, and further improving the impact resistance and stability of the battery cell when it is dropped. The first accommodating cavity formed by stamping can better match the contour of the first pole piece group, and the second accommodating cavity can better match the contour of the second pole piece group. Therefore, the gap between the first pole piece group and the cavity wall of the first accommodating cavity is smaller, and the gap between the second pole piece group and the cavity wall of the second accommodating cavity is smaller, reducing the space waste of the first accommodating cavity and the second accommodating cavity, which is beneficial to improving the energy density of the battery cell.

[0022] In some embodiments of the first aspect of the present application, along the first direction, the first pole piece group is completely accommodated in the first accommodation cavity, and the second pole piece group is completely accommodated in the second accommodation cavity.

[0023] In one or more of the above optional embodiments, the first electrode plate group is completely accommodated in the first accommodating cavity along the first direction, and the second electrode plate group is completely accommodated in the second accommodating cavity along the first direction, so that the contour of the first accommodating cavity can better match the first electrode plate group, and the contour of the second accommodating cavity can better match the second electrode plate group, thereby reducing the gap between the first electrode plate group and the cavity wall of the first accommodating cavity, and reducing the gap between the second electrode plate group and the cavity wall of the second accommodating cavity, thereby alleviating the problem of shaking of the electrode assembly, which is beneficial to improving the safety and reliability of the battery cell, and reducing the space waste between the first accommodating cavity and the second accommodating cavity, which is beneficial to improving the energy density of the battery cell.

[0024] In some embodiments of the first aspect of the present application, along the first direction, the first pole piece group has a first inner pole piece closest to the second pole piece group, the second shell has a first step wall facing the first inner pole piece and closest to the first inner pole piece, the first step wall and the second pole piece group are located on the same side of the first pole piece group, and the distance between the first step wall and the first inner pole piece is L 1 , 0mm≤L 1 ≤0.5mm.

[0025] In one or more of the above optional embodiments, along the first direction, the distance between the first step wall and the first inner pole piece of the first pole piece group closest to the second pole piece group is less than or equal to 0.5 mm, so that the distance between the first step wall and the first pole piece group in the first direction is small enough to reduce the risk of the first pole piece group shaking in the first accommodating cavity or reduce the degree of shaking of the first pole piece group in the first accommodating cavity, alleviate the problem of drop failure, and thus improve the impact resistance and stability of the battery cell when it is dropped. The distance between the first cavity wall and the first pole piece group in the first direction is small enough to reduce the space waste of the first accommodating cavity, which is conducive to improving the energy density of the battery cell.

[0026] In some embodiments of the first aspect of the present application, there is a first gap between the first pole piece group and the cavity wall of the first accommodating cavity. When viewed along the first direction, the first gap extends along the circumference of the first pole piece group, and the width of the first gap is W. 1 , 0.01mm≤W 1 ≤1mm.

[0027] In one or more of the above optional embodiments, by making the width of the first gap greater than or equal to 0.01mm, the risk of friction between the pole piece of the first pole piece group and the cavity wall of the first accommodating cavity puncturing the packaging can be reduced, thereby improving the safety performance of the battery cell. The width of the first gap is greater than or equal to 0.01mm, which reserves an assembly margin for the first pole piece group to enter the shell, reduces the risk of interference between the first pole piece group and the cavity wall of the first accommodating cavity during the process of the first pole piece group entering the shell, makes it more convenient for the first pole piece group to enter the shell, and is beneficial to improving the assembly quality of the battery cell. The width of the first gap is less than or equal to 1mm, so that the distance between the cavity wall of the first accommodating cavity and the outer periphery of the first pole piece group is small enough, reducing the risk of the first pole piece group shaking in the first accommodating cavity or reducing the degree of shaking of the first pole piece group in the first accommodating cavity, alleviating the problem of drop failure, thereby improving the impact resistance and stability of the battery cell when it is dropped, and reducing the space waste of the first accommodating cavity, which is beneficial to improving the energy density of the battery cell. Therefore, 0.01mm≤W 1 ≤1mm, which is beneficial to improving the safety, assembly quality, impact resistance and stability of the battery cell when it is dropped, as well as improving the energy density of the battery cell.

[0028] In some embodiments of the first aspect of the present application, along the second direction, the first pole piece group has a first portion that extends beyond the second pole piece group, the second accommodating cavity has a second cavity wall disposed facing the second pole piece group, the second cavity wall is located on a side of the second pole piece group close to the first portion, and the distance between the second cavity wall and the second pole piece group is L2, 0.01mm≤L2≤1mm.

[0029] In one or more optional embodiments above, by making the distance between the second cavity wall and the second pole piece group along the second direction greater than or equal to 0.01mm, the risk of the pole piece of the second pole piece group and the second cavity wall rubbing against the packaging can be reduced, the safety performance of the battery cell can be improved, and the assembly margin can be provided for the second pole piece group to enter the shell, reducing the risk of interference between the second pole piece group and the second cavity wall during the process of the second pole piece group entering the shell, making the second pole piece group more convenient to enter the shell, and helping to improve the assembly quality of the battery cell. By making the distance between the second cavity wall and the second pole piece group along the second direction greater than or equal to 1mm, the distance between the second cavity wall and the second pole piece group is small enough, reducing the risk of the second pole piece group shaking in the second accommodating cavity or slowing down the shaking degree of the second pole piece group in the second accommodating cavity, alleviating the problem of falling failure, thereby improving the impact resistance and stability of the battery cell when it is dropped, and reducing the space waste of the second accommodating cavity, which is conducive to improving the energy density of the battery cell. Therefore, 0.01mm≤L2≤1mm is conducive to improving the safety performance, assembly quality and energy density of the battery cell.

[0030] In some embodiments of the first aspect of the present application, there is a second gap between the second pole piece group and the cavity wall of the second accommodating cavity. When observed along the first direction, the second gap extends circumferentially along the second pole piece group. The width of the second gap is W2, 0.01mm≤W2≤1mm.

[0031] In one or more optional embodiments above, the width of the second gap is greater than or equal to 0.01mm, which can reduce the risk of the electrode of the second electrode group and the cavity wall of the second accommodating cavity puncturing the package by friction, and improve the safety performance of the battery cell. The width of the second gap is greater than or equal to 0.01mm, which reserves an assembly margin for the second electrode group to enter the shell, reduces the risk of interference between the second electrode group and the cavity wall of the second accommodating cavity during the process of the second electrode group entering the shell, and the second electrode group is more convenient to enter the shell, and is conducive to improving the assembly quality of the battery cell. The width of the second gap is less than or equal to 1mm, so that the distance between the cavity wall of the second accommodating cavity and the outer periphery of the second electrode group is small enough, reducing the risk of the second electrode group shaking in the second accommodating cavity or slowing down the shaking degree of the second electrode group in the second accommodating cavity, alleviating the problem of falling failure, thereby improving the impact resistance and stability of the battery cell when it is dropped, and reducing the space waste of the second accommodating cavity, which is conducive to improving the energy density of the battery cell. Therefore, 0.01mm≤W2≤1mm is conducive to improving the safety, assembly quality, impact resistance and stability of the battery cell when it is dropped, and improving the energy density of the battery cell.

[0032] In some embodiments of the first aspect of the present application, the battery cell is a soft-pack battery cell.

[0033] In one or more optional embodiments above, the battery cell is a soft-pack battery cell, and the first shell and the second shell are both made of softer materials, a first accommodating cavity is provided on the surface of the softer first shell facing the second shell, and a second accommodating cavity is provided on the surface of the softer second shell facing the first shell, along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity, along the first direction, at least part of the first pole piece group is accommodated in the first accommodating cavity, and at least part of the second pole piece group is accommodated in the second accommodating cavity, compared with forming a cavity whose depth along the first direction is the sum of the depths of the first accommodating cavity and the second accommodating cavity only in the first shell, and compared with forming a cavity only in the second direction The shell forms a chamber whose depth along the first direction is the sum of the depth of the first accommodating cavity and the depth of the second accommodating cavity. In this solution, the depths of the first accommodating cavity of the first shell and the second accommodating cavity of the second shell are both small, and the processing difficulty is relatively small. The space formed by the first accommodating cavity and the second accommodating cavity has a higher matching degree with the contour of the electrode assembly. The first shell and the second shell can better restrain the first pole piece group and the second pole piece group, reduce the risk of the electrode assembly shaking in the space formed by the first accommodating cavity and the second accommodating cavity or reduce the degree of shaking, alleviate the problem of falling failure, and thus improve the impact resistance and stability of the battery cell when it falls. In addition, the first accommodating cavity of this solution can better match the contour of the first pole piece group, and the second accommodating cavity can better match the contour of the second pole piece group. Therefore, the gap between the first pole piece group and the cavity wall of the first accommodating cavity is smaller, and the gap between the second pole piece group and the cavity wall of the second accommodating cavity is smaller, reducing the space waste of the first accommodating cavity and the second accommodating cavity, which is conducive to improving the energy density of the battery cell.

[0034] In a second aspect, an embodiment of the present application further provides an electrical device, the electrical device comprising a battery cell provided in any embodiment of the first aspect.

[0035] In one or more of the above optional embodiments, the battery cell provided in any embodiment of the first aspect has good safety performance, good impact resistance and stability when falling, and high energy density, which is beneficial to improving the power safety performance and power reliability of electrical equipment powered by the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope.

[0037] Figure 1 A cross-sectional view of a battery cell provided in some embodiments of the present application;

[0038] Figure 2 A schematic diagram of an electrode assembly along a third direction provided in some embodiments of the present application;

[0039] Figure 3 A schematic diagram of an electrode assembly along a second direction provided in some embodiments of the present application;

[0040] Figure 4 A cross-sectional view of a first shell and a second shell after being packaged according to some embodiments of the present application from a certain perspective;

[0041] Figure 5 A cross-sectional view from another perspective after the first shell and the second shell are packaged according to some embodiments of the present application;

[0042] Figure 6 for Figure 1 The enlarged view of A1 in the middle;

[0043] Figure 7 A cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0044] Figure 8 for Figure 7 The enlarged view of A2 in the middle;

[0045] Fig. 9 A schematic diagram of the cooperation between the first side wall of the first housing and the first pole piece group provided in some embodiments of the present application;

[0046] Fig.10 for Figure 1 The enlarged view of A3 in the middle;

[0047] Fig.11 for Figure 1 The enlarged view of the A4 position in the middle;

[0048] Fig.12 A schematic diagram of the cooperation between the second side wall of the second housing and the first electrode assembly provided in some embodiments of the present application;

[0049] Fig.13 A schematic diagram of a first shell and a second shell in an unpackaged state provided in some embodiments of the present application;

[0050] Fig.14 A schematic diagram of a first shell and a second shell provided in some other embodiments of the present application being separately arranged;

[0051] Fig.15 A schematic diagram of a first shell and a second shell after packaging provided in some embodiments of the present application;

[0052] Fig.16 A schematic diagram of a first shell and a second shell after being packaged according to some other embodiments of the present application;

[0053] Fig.17A schematic diagram of a first housing and a second housing that are not encapsulated provided in some further embodiments of the present application;

[0054] Fig.18 Schematic diagram of the first shell and the second shell not being encapsulated provided for some other embodiments of the present application.

[0055] Icon: 100-battery cell; 10-packaging; 11-first shell; 111-first accommodating cavity; 111'-first protrusion; 112-first end wall; 113-first side wall; 114-first opening; 115-first sealing portion; 116-first edge; 117-first surface; 12-second shell; 121-second accommodating cavity; 121'-second protrusion; 122-second end wall; 123-second side wall; 1231-second cavity wall; 124-second opening; 125-second Second sealing part; 126-first step wall; 127-second edge; 128-second surface; 13-bending part; 20-electrode assembly; 21-first pole piece group; 211-first part; 212-first inner pole piece; 22-second pole piece group; 20'-pole piece; 20'a-positive pole piece; 20'b-negative pole piece; 20b-separation membrane; 30-insulating member; 40-sealing member; X-first direction; Y-second direction; Z-third direction; Q1-first gap; Q2-second gap. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0057] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed for protection, but merely represents selected embodiments of the present application. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0059] In the description of the embodiments of the present application, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0060] At present, judging from the development of the market situation, the application of battery cells is becoming more and more extensive. Battery cells are widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, as well as electric tools, drones, energy storage equipment and other fields. With the continuous expansion of the application fields of battery cells, the market demand is also constantly expanding.

[0061] The battery cell includes a wound battery cell and a laminated battery cell. The electrode assembly of the laminated battery cell includes a plurality of pole pieces with opposite polarities alternately stacked. As a type of laminated battery cell, the electrode assembly of the step battery cell includes at least a first pole piece group and a second pole piece group, the first pole piece group and the second pole piece group are stacked along a first direction, along the second direction, the length of the first pole piece group is greater than the length of the second pole piece group, and the second direction is perpendicular to the first direction.

[0062] In the related art, the step battery cell also includes a packaging, which includes a first shell and a second shell, and the electrode assembly is accommodated in a space defined by the first shell and the second shell. In order to make the packaging of the step battery cell match the appearance of the electrode assembly and slow down the shaking of the electrode assembly in the packaging, a stepped space is formed in the packaging so that the shape of the space in the packaging matches the contour of the electrode assembly. However, the stepped space in the packaging is only formed in the first shell of the packaging, which makes the depth of the space formed by the first shell larger. If a single stamping method is used to form a stepped space with a larger depth on the first shell, the process difficulty is greater. If multiple stamping methods are used to form a stepped space with a larger depth on the first shell, for example, the first stamping of the first shell forms a larger space, and the second stamping forms a smaller space, then the second stamping will affect the space formed by the first stamping, so that the formed space shape is less matched with the packaging of the electrode assembly. During the falling process, the electrode assembly cannot be restrained by the packaging and moves, which aggravates the problem of falling failure and the safety of the battery cell is lower. At the same time, it will cause waste of space in the packaging and lead to reduced energy density.

[0063] Based on the above considerations, in order to improve the safety and energy density of the battery cell, an embodiment of the present application provides a battery cell, which includes an electrode assembly, a first shell and a second shell; the electrode assembly includes a first pole piece group and a second pole piece group, the first pole piece group and the second pole piece group are stacked along a first direction, along the second direction, the length of the first pole piece group is greater than the length of the second pole piece group, and the second direction is perpendicular to the first direction; the first shell and the second shell are arranged opposite to each other along the first direction, a first accommodating cavity is provided on the surface of the first shell facing the second shell, and a second accommodating cavity is provided on the surface of the second shell facing the first shell, along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity, along the first direction, at least a portion of the first pole piece group is accommodated in the first accommodating cavity, and at least a portion of the second pole piece group is accommodated in the second accommodating cavity.

[0064] A first accommodating cavity is provided on the surface of the first shell facing the second shell, and a second accommodating cavity is provided on the surface of the second shell facing the first shell. Along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity. Along the first direction, at least part of the first electrode group is accommodated in the first accommodating cavity, and at least part of the second electrode group is accommodated in the second accommodating cavity. Compared with a solution in which a chamber whose depth along the first direction is the sum of the depths of the first accommodating cavity and the second accommodating cavity is formed only in the first shell, and compared with a solution in which a chamber whose depth along the first direction is the sum of the depths of the first accommodating cavity and the second accommodating cavity is formed only in the second shell, in this solution, the depths of the first accommodating cavity of the first shell and the second accommodating cavity of the second shell are both smaller, the processing difficulty is smaller, and the space formed by the first accommodating cavity and the second accommodating cavity has a higher matching degree with the contour of the electrode assembly. The first shell and the second shell can better restrain the first electrode group and the second electrode group, reduce the risk of the electrode assembly shaking in the space formed by the first accommodating cavity and the second accommodating cavity or reduce the degree of shaking, alleviate the problem of drop failure, thereby improving the impact resistance and stability of the battery cell when it is dropped.

[0065] In addition, the first accommodating cavity of the present solution can better match the contour of the first pole piece group, and the second accommodating cavity can better match the contour of the second pole piece group. Therefore, the gap between the first pole piece group and the cavity wall of the first accommodating cavity is smaller, and the gap between the second pole piece group and the cavity wall of the second accommodating cavity is smaller, thereby reducing the space waste of the first accommodating cavity and the second accommodating cavity, which is beneficial to improving the energy density of the battery cell.

[0066] The battery cell disclosed in the embodiment of the present application can be used in, but not limited to, electric two-wheeled vehicles, electric tools, drones, energy storage devices and other electrical equipment. The battery cell with the working conditions of the present application can also be used as a power supply system for electrical equipment.

[0067] The present application provides an electric device using a battery cell as a power source, and the electric device may be, but is not limited to, electronic equipment, electric tools, electric vehicles, drones, and energy storage devices. Among them, electronic equipment may include mobile phones, tablets, laptops, etc., electric tools may include electric drills, electric saws, etc., and electric vehicles may include electric cars, electric motorcycles, electric bicycles, etc.

[0068] like Figure 1 As shown, the embodiment of the present application provides a battery cell 100 , which includes a package 10 and an electrode assembly 20 . The electrode assembly 20 is accommodated in the package 10 .

[0069] The package 10 may be a hard shell, for example, the package 10 is a stainless steel shell or an aluminum hard shell, forming a steel shell battery or an aluminum shell battery.

[0070] The packaging 10 may also be made of a relatively soft material, such as an aluminum plastic film or a steel plastic film, to form a soft-pack battery cell. Figure 1 As shown, the battery cell 100 is a soft-pack battery cell.

[0071] like Figure 2 , Figure 3 As shown, the electrode assembly 20 includes a first electrode plate group 21 and a second electrode plate group 22. The first electrode plate group 21 and the second electrode plate group 22 are stacked along a first direction X. Along the second direction Y, the length of the first electrode plate group 21 is greater than the length of the second electrode plate group 22. The second direction Y is perpendicular to the first direction X.

[0072] The first pole piece group 21 includes a plurality of pole pieces stacked along a first direction X. Two adjacent pole pieces in the first pole piece group 21 have opposite polarities, that is, one of the two adjacent pole pieces 20' in the first pole piece group 21 is a positive pole piece 20'a, and the other is a negative pole piece 20'b. An isolation film 20b is provided between the two adjacent pole pieces 20' in the first pole piece group 21, and the isolation film 20b is used to insulate and separate the two adjacent pole pieces with opposite polarities in the first pole piece group 21. In the first pole piece group 21, along the second direction Y, the two ends of the negative pole piece exceed the two ends of the positive pole piece, and along the third direction Z, the two ends of the negative pole piece exceed the two ends of the positive pole piece, so as to reduce the risk of lithium deposition in the battery cell 100. Among them, the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0073] The first pole piece group 21 includes a first outer pole piece farthest from the second pole piece group 22. The first outer pole piece may be a pole piece coated with an active material layer on one side, which is beneficial to reduce the active material that does not play a capacity role and improve the energy density of the battery cell 100. Of course, the first outer pole piece may also be a pole piece coated with active material on both sides. The first outer pole piece may be a positive pole piece or a negative pole piece.

[0074] The second pole piece group 22 includes a plurality of pole pieces 20' stacked along the first direction X. Two adjacent pole pieces 20' in the second pole piece group 22 have opposite polarities, that is, one of the two adjacent pole pieces 20' in the second pole piece group 22 is a positive pole piece 20'a, and the other is a negative pole piece 20'b. An isolation film 20b is provided between two adjacent pole pieces 20' in the second pole piece group 22, and the isolation film 20b is used to insulate and separate two adjacent pole pieces 20' of opposite polarities in the second pole piece group 22. In the second pole piece group 22, along the second direction Y, the two ends of the negative pole piece exceed the two ends of the positive pole piece, and along the third direction Z, the two ends of the negative pole piece exceed the two ends of the positive pole piece, so as to reduce the risk of lithium deposition in the battery cell 100.

[0075] Along the first direction X, the first pole piece group 21 has a first inner pole piece 212 closest to the second pole piece group 22, and the second pole piece group 22 has a second inner pole piece closest to the first pole piece group 21, and the active layer of at least one side of the first inner pole piece 212 facing the second inner pole piece has an opposite polarity to the active layer of the side of the second inner pole piece facing the first inner pole piece 212.

[0076] The second pole piece group 22 includes a second outer pole piece farthest from the first pole piece group 21. The second outer pole piece can be a pole piece coated with an active material layer on one side, which is beneficial to reduce the active material that does not play the capacity and improve the energy density of the battery cell 100. Of course, the second outer pole piece can also be a pole piece coated with active material on both sides. The second outer pole piece can be a positive pole piece or a negative pole piece.

[0077] The isolation film 20b insulates and separates the two pole pieces 20' with opposite polarities, thereby reducing the risk of short circuit of the battery cell 100. The isolation film 20b may be made of PP (polypropylene) or PE (polyethylene).

[0078] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, at least one side of the positive electrode current collector is provided with a positive electrode active material layer, the material of the positive electrode current collector may include aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, at least one side of the negative electrode current collector is provided with a negative electrode active material layer, the material of the negative electrode current collector may include copper, and the negative electrode active material may be carbon or silicon, etc.

[0079] like Figure 2 , Figure 3 As shown, along the second direction Y, the first pole piece group 21 exceeds one end of the second pole piece group 22, the first pole piece group 21 has a first portion 211 that exceeds the second pole piece group 22, and the other end of the first pole piece group 21 is flush with the other end of the second pole piece group 22. Along the third direction Z, both ends of the first pole piece group 21 and the second pole piece group 22 can be flush.

[0080] It should be noted that, in the first pole piece group 21, along the second direction Y, the size of the positive pole piece and the size of the negative pole piece are both smaller than the size of the isolation membrane 20b, and along the third direction Z, the size of the positive pole piece and the size of the negative pole piece are both smaller than the size of the isolation membrane 20b. Therefore, along the second direction Y, the two ends of the first pole piece group 21 can be the two ends of the isolation membrane 20b in the first pole piece group 21 along the second direction Y, and along the third direction Z, the two ends of the first pole piece group 21 can be the two ends of the isolation membrane 20b in the first pole piece group 21 along the third direction Z.

[0081] In the second pole piece group 22, along the second direction Y, the size of the positive pole piece and the size of the negative pole piece are both smaller than the size of the isolation membrane 20b, and along the third direction Z, the size of the positive pole piece and the size of the negative pole piece are both smaller than the size of the isolation membrane 20b. Therefore, along the second direction Y, the two ends of the second pole piece group 22 can be the two ends of the isolation membrane 20b in the second pole piece group 22 along the second direction Y, and along the third direction Z, the two ends of the second pole piece group 22 can be the two ends of the isolation membrane 20b in the second pole piece group 22 along the third direction Z.

[0082] Along the second direction Y, the other end of the first pole piece group 21 and the other end of the second pole piece group 22 are flush, but not absolutely flush. The distance between the other end of the first pole piece group 21 and the other end of the second pole piece group 22 in the second direction Y is allowed to have a manufacturing error. For example, the distance between the other end of the first pole piece group 21 and the other end of the second pole piece group 22 in the second direction Y differs by ±1mm.

[0083] Along the third direction Z, the two ends of the first pole piece group 21 and the two ends of the second pole piece group 22 are not absolutely flush, and the distance between the two ends of the first pole piece group 21 in the third direction Z and the two ends of the second pole piece group 22 in the third direction Z is allowed to have manufacturing errors, such as the distance between one end of the first pole piece group 21 and the corresponding end of the second pole piece group 22 in the third direction Z differs by ±1mm.

[0084] Combined with reference Figure 1 , Figure 4 The package 10 includes a first shell 11 and a second shell 12, which are arranged opposite to each other along a first direction X. A first accommodating cavity 111 is provided on a surface of the first shell 11 facing the second shell 12, and a second accommodating cavity 121 is provided on a surface of the second shell 12 facing the first shell 11. Along the second direction Y, the length of the first accommodating cavity 111 is greater than the length of the second accommodating cavity 121. Along the first direction X, at least a portion of the first pole piece group 21 is accommodated in the first accommodating cavity 111, and at least a portion of the second pole piece group 22 is accommodated in the second accommodating cavity 121.

[0085] A first accommodating cavity 111 is provided on the surface of the first shell 11 facing the second shell 12, and a second accommodating cavity 121 is provided on the surface of the second shell 12 facing the first shell 11. Along the second direction Y, the length of the first accommodating cavity 111 is greater than the length of the second accommodating cavity 121. Along the first direction X, at least part of the first pole piece group 21 is accommodated in the first accommodating cavity 111, and at least part of the second pole piece group 22 is accommodated in the second accommodating cavity 121. Compared with a solution in which a chamber whose depth along the first direction X is the sum of the depths of the first accommodating cavity 111 and the second accommodating cavity 121 is formed only in the first shell 11, and compared with a solution in which a chamber whose depth along the first direction X is the sum of the depths of the first accommodating cavity 111 and the second accommodating cavity 121 is formed only in the second shell 12, this method In the case, the depths of the first accommodating cavity 111 of the first shell 11 and the second accommodating cavity 121 of the second shell 12 are both relatively small, and the processing difficulty is relatively low. In the step battery, the first accommodating cavity 111 and the second accommodating cavity 121 can form corresponding accommodating cavities according to the size of the battery cells (the first electrode plate group 21 and the second electrode plate group 22), respectively, so that the formed space has a higher matching degree with the contour of the electrode assembly 20. The first shell 11 and the second shell 12 can better restrain the first electrode plate group 21 and the second electrode plate group 22, reduce the risk of the electrode assembly 20 shaking in the space formed by the first accommodating cavity 111 and the second accommodating cavity 121 or reduce the degree of shaking, alleviate the problem of falling failure, and thus improve the impact resistance and stability of the battery cell 100 when it is dropped.

[0086] In addition, the first accommodating cavity 111 of the present scheme can better match the contour of the first pole piece group 21, and the second accommodating cavity 121 can better match the contour of the second pole piece group 22. Therefore, the gap between the first pole piece group 21 and the cavity wall of the first accommodating cavity 111 is smaller, and the gap between the second pole piece group 22 and the cavity wall of the second accommodating cavity 121 is smaller, thereby reducing the space waste of the first accommodating cavity 111 and the second accommodating cavity 121, which is beneficial to improving the energy density of the battery cell 100.

[0087] The first accommodating cavity 111 is a recessed portion formed by a surface of the first shell 11 facing the second shell 12 being recessed in a direction away from the second shell 12 .

[0088] The depth of the first accommodating cavity 111 in the first direction X can be equal to the size of the first pole piece group 21 in the first direction X, then the first pole piece group 21 can be completely accommodated in the first accommodating cavity 111, and the first accommodating cavity 111 can be fully used to accommodate the first pole piece group 21, the gap between the first shell 11 and the second shell 12 and the electrode assembly 20 is small, the space formed by the first accommodating cavity 111 and the second accommodating cavity 121 has a higher matching degree with the contour of the electrode assembly 20, the first shell 11 and the second shell 12 can better restrain the first pole piece group 21 and the second pole piece group 22, reduce the risk of the electrode assembly 20 shaking in the space formed by the first accommodating cavity 111 and the second accommodating cavity 121 or reduce the degree of shaking, alleviate the problem of fall failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped, and reducing the space waste of the first accommodating cavity 111, which is conducive to improving the energy density of the battery cell 100.

[0089] The depth of the first accommodating cavity 111 in the first direction X may be greater than the dimension of the first pole piece group 21 in the first direction X, and part of the second pole piece group 22 may be accommodated in the first accommodating cavity 111 .

[0090] The second accommodating cavity 121 is a concave portion formed by the surface of the second shell 12 facing the first shell 11 being concave in a direction away from the first shell 11. The depth of the second accommodating cavity 121 concave in the first direction X can be equal to the size of the second pole piece group 22 in the first direction X, so that the second pole piece group 22 can be completely accommodated in the second accommodating cavity 121, and the second accommodating cavity 121 can be fully used to accommodate the second pole piece group 22, the gap between the first shell 11 and the second shell 12 and the electrode assembly 20 is small, the space formed by the first accommodating cavity 111 and the second accommodating cavity 121 has a higher matching degree with the contour of the electrode assembly 20, the first shell 11 and the second shell 12 can better restrain the first pole piece group 21 and the second pole piece group 22, reduce the risk of the electrode assembly 20 shaking in the space formed by the first accommodating cavity 111 and the second accommodating cavity 121 or reduce the degree of shaking, alleviate the problem of falling failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped, and reducing the space waste of the second accommodating cavity 121, which is conducive to improving the energy density of the battery cell 100.

[0091] The depth of the second accommodating cavity 121 in the first direction X may be smaller than the dimension of the second pole piece group 22 in the first direction X. Then, along the first direction X, a portion of the second pole piece group 22 is accommodated in the second accommodating cavity 121 .

[0092] Of course, the depth of the second accommodating cavity 121 in the first direction X may also be greater than the dimension of the second pole piece group 22 in the first direction X.

[0093] Figure 1, it is shown that, along the first direction X, the first pole piece group 21 is completely accommodated in the first accommodation cavity 111 , and the second pole piece group 22 is completely accommodated in the second accommodation cavity 121 .

[0094] By completely accommodating the first electrode group 21 in the first accommodating cavity 111 along the first direction X, and completely accommodating the second electrode group 22 in the second accommodating cavity 121 along the first direction X, the contour of the first accommodating cavity 111 can better match the first electrode group 21, and the contour of the second cavity can better match the second electrode group 22, thereby reducing the gap between the first electrode group 21 and the cavity wall of the first accommodating cavity 111, and reducing the gap between the second electrode group 22 and the cavity wall of the second accommodating cavity 121, thereby alleviating the problem of shaking of the electrode assembly 20, which is beneficial to improving the safety and reliability of the battery cell 100, and reducing the space waste of the first accommodating cavity 111 and the second accommodating cavity 121, which is beneficial to improving the energy density of the battery cell 100.

[0095] The first accommodating cavity 111 can be formed by a notching process, a stamping process, a casting process, etc. Exemplarily, the first accommodating cavity 111 is stamped on the first shell 11 . It can be understood that the first accommodating cavity 111 is formed by stamping the first shell 11 .

[0096] The second accommodating cavity 121 can be formed by a notching process, a stamping process, a casting process, etc. Exemplarily, the second accommodating cavity 121 is stamped and formed on the second shell 12 . It can be understood that the second accommodating cavity 121 is formed by stamping the second shell 12 .

[0097] The first housing 111 and the second housing 12 are respectively formed by stamping in the first housing 11 and the second housing 12. The first housing 111 and the second housing 121 are easy to form and have high dimensional accuracy, so that the first housing 111 and the second housing 121 can better match the first pole piece group 21 and the second pole piece group 22, alleviate the shaking problem of the electrode assembly 20, and thus alleviate the problem of falling failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped. The first housing 111 formed by stamping can better match the contour of the first pole piece group 21, and the second housing 121 can better match the contour of the second pole piece group 22, so that the gap between the first pole piece group 21 and the cavity wall of the first housing 111 is smaller, and the gap between the second pole piece group 22 and the cavity wall of the second housing 121 is smaller, reducing the space waste of the first housing 111 and the second housing 121, which is conducive to improving the energy density of the battery cell 100.

[0098] like Figure 4As shown, in some embodiments, along the first direction X, a first protrusion 111 ′ is formed at a position corresponding to the first accommodation cavity 111 on the surface of the first shell 11 facing away from the second shell 12 .

[0099] For example, the plate-shaped first shell 11 is stamped to form a concave first accommodating cavity 111 on one side of the first shell 11 in the thickness direction, and a first protruding portion 111 ′ is formed at a position corresponding to the first accommodating cavity 111 on the other side of the first shell 11 in the thickness direction.

[0100] A first protrusion 111 ′ is formed at a position corresponding to the first accommodating cavity 111 on the surface of the first shell 11 away from the second shell 12 along the first direction X, which is beneficial to reducing the thickness difference of each part of the first shell 11 and improving the strength of the first shell 11 .

[0101] In some embodiments, a second protrusion 121 ′ is formed on a surface of the second shell 12 facing away from the first shell 11 and at a position corresponding to the second accommodating cavity 121 .

[0102] For example, the second shell 12 of the plate-like structure is stamped to form a recessed second accommodating cavity 121 on one side of the second shell 12 in the thickness direction, and a second protruding portion 121 ′ is formed at a position corresponding to the second accommodating cavity 121 on the other side of the second shell 12 in the thickness direction.

[0103] A second protrusion 121 ′ is formed at a position corresponding to the second accommodating cavity 121 on the surface of the second shell 12 away from the first shell 11 along the first direction X, which is beneficial to reducing the thickness difference of each part of the second shell 12 and improving the strength of the second shell 12 .

[0104] In addition, a second protrusion 121' is formed at a position corresponding to the second accommodating cavity 121 on the surface of the second shell 12 facing away from the first shell 11, which is conducive to reducing the thickness difference of each part of the second shell 12 and improving the strength of the second shell 12. A first protrusion 111' is formed at a position corresponding to the first accommodating cavity 111 on the surface of the first shell 11 facing away from the second shell 12, and a second protrusion 121' is formed at a position corresponding to the second accommodating cavity 121 on the surface of the second shell 12 facing away from the first shell 11, so that the outer contours of the first shell 11 and the second shell 12 can better adapt to the special-shaped installation space, which is conducive to reducing the volume of the electrical equipment powered by the power supply.

[0105] Of course, in some other embodiments, the surface of the first shell 11 facing away from the second shell 12 may be a plane, and the surface of the second shell 12 facing away from the first shell 11 may be a plane.

[0106] like Figure 4As shown, the first shell 11 includes a first end wall 112 and a first side wall 113. The first side wall 113 is arranged around the outer periphery of the first end wall 112. Along the first direction X, one end of the first side wall 113 is connected to the first end wall 112, and the other end of the first side wall 113 forms a first opening 114. The first end wall 112 and the first side wall 113 together define a first accommodating cavity 111. The first shell 11 also includes a first sealing portion 115. The first sealing portion 115 is connected to the first side wall 113 to form one end of the first opening 114. When viewed along the first direction X, the first sealing portion 115 can extend along the circumference of the first accommodating cavity 111, that is, when viewed along the first direction X, the first sealing portion 115 can surround the first accommodating cavity 111 at an angle of 360°. The first sealing portion 115 is arranged around the first accommodating cavity 111. The edge of the first sealing portion 115 is the edge of the first shell 11.

[0107] The second housing 12 includes a second end wall 122 and a second side wall 123. The second side wall 123 is disposed around the outer periphery of the second end wall 122. One end of the second side wall 123 is connected to the second end wall 122 along the first direction X, and the other end of the second side wall 123 forms a second opening 124. The second opening 124 and the first opening 114 are disposed opposite to each other, that is, the first accommodating cavity 111 forms the first opening 114 on the surface of the first housing 11 facing the second housing 12, and the second accommodating cavity 121 forms the second opening 124 on the surface of the second housing 12 facing the first housing 11.

[0108] The second end wall 122 and the second side wall 123 together define a second accommodating cavity 121. The second end wall 122 and the first end wall 112 are arranged opposite to each other in the first direction X. The first end wall 112 is located on a side of the first pole piece group 21 away from the second pole piece group 22, and the second end wall 122 is located on a side of the second pole piece group 22 away from the first pole piece group 21.

[0109] The second shell 12 also includes a first step wall 126 and a second sealing portion 125. The first step wall 126 is connected to the second side wall 123 to form one end of the second opening 124. Along the first direction X, the first step wall 126 and the second end wall 122 are respectively connected to the two ends of the second side wall 123, and the first step wall 126 is closer to the first pole piece group 21 than the second end wall 122. Along the first direction X, the first step portion and the second pole piece group 22 are located on the same side of the first pole piece group 21. The first step wall 126 is arranged opposite to the portion of the first pole piece group 21 that exceeds the second pole piece group 22. Figure 1 In the embodiment, the first step wall 126 is arranged opposite to the first portion 211 .

[0110] The second sealing portion 125 may extend along the circumference of the first accommodating cavity 111, and the second sealing portion 125 is disposed around the second accommodating cavity 121. The edge of the second sealing portion 125 is the edge of the second housing 12. A portion of the second sealing portion 125 is connected to an end of the first step wall 126 away from the second side wall 123 along the second direction Y, and another portion of the second sealing portion 125 may be connected to an end of the second side wall 123 forming the second opening 124.

[0111] At least a portion of the first sealing portion 115 is sealed to at least a portion of the second sealing portion 125. For example, in an embodiment in which the first shell 11 and the second shell 12 are separately provided and connected, along the circumference of the first opening 114, the entire area of ​​the first sealing portion 115 and the entire area of ​​the second sealing portion 125 are sealed to each other. In an embodiment in which a portion of the edge of the first shell 11 and a portion of the edge of the second shell 12 are connected via a bending portion 13, it can be understood that a portion of the edge of the first sealing portion 115 and a portion of the edge of the second sealing portion 125 are connected via the bending portion 13, and an area of ​​the first sealing portion 115 not connected to the bending portion 13 is sealed to an area of ​​the second sealing portion 125 not connected to the bending portion 13, that is, a portion of the first sealing portion 115 and a portion of the second sealing portion 125 are sealed to each other.

[0112] The surface of the first sealing portion 115 facing the second housing 12 is a part of the first surface 117. The surface of the second sealing portion 125 facing the first housing 11 is a part of the second surface 128. After the first sealing portion 115 and the second sealing portion 125 are sealed and connected, they can be wound to contact the wall of the first accommodating cavity 111 and / or the wall of the second accommodating cavity 121, thereby reducing the size of the battery cell 100.

[0113] There are many ways to seal the first sealing part 115 and the second sealing part 125. For example, the first sealing part 115 and the second sealing part 125 can be sealed by thermal bonding, hot melt adhesive, sealant, etc.

[0114] The first shell 11 and the second shell 12 are sealed and connected via the first sealing portion 115 and the second sealing portion 125 , so as to improve the sealing performance of the battery cell 100 , thereby facilitating improving the safety performance of the battery cell 100 .

[0115] Combined with reference Figure 1 , Figure 4 In some embodiments, along the second direction Y, one end of the first opening 114 is flush with one end of the second opening 124 , and the first opening 114 exceeds the other end of the second opening 124 .

[0116] In the second direction Y, one end of the first opening 114 and the second opening 124 that is flush with each other corresponds to one end of the first pole piece group 21 and the second pole piece group 22 that is flush with each other.

[0117] Along the second direction Y, the first opening 114 exceeds the other end of the second opening 124 , and the portion of the first electrode set 21 that exceeds the second electrode set 22 is accommodated in a space corresponding to the portion of the first opening 114 that exceeds the second opening 124 .

[0118] Along the second direction Y, one end of the first opening 114 is flush with one end of the second opening 124, which can provide positioning for the first electrode set 21 and the second electrode set 22 when the electrode assembly 20 is placed in the shell, and can also standardize the structure of the electrode assembly 20, making it easier for the electrode assembly 20 to be placed in the shell. The first opening 114 exceeds the other end of the second opening 124, so that the size of the first accommodating cavity 111 in the second direction Y can match the first electrode set 21, and the size of the second accommodating cavity 121 in the second direction Y can match the second electrode set 22, thereby facilitating the placement of the electrode assembly 20 in the shell.

[0119] like Figure 5 As shown, along the third direction Z, the two ends of the first opening 114 are flush with the two ends of the second opening 124, which facilitates the electrode assembly 20 to enter the shell and the first pole piece group 21 and the second pole piece group 22 to match the first accommodating cavity 111 and the second accommodating cavity 121 respectively. It can also standardize the structure of the electrode assembly 20 in the third direction Z and reduce the risk of the pole piece moving along the third direction Z.

[0120] Combination Figure 1 , Figure 6 , Figure 7-Figure 8 As shown, in some embodiments, along the first direction X, the first pole piece group 21 has a first inner pole piece 212 closest to the second pole piece group 22, the second shell 12 has a first step wall 126 facing the first inner pole piece 212 and closest to the first inner pole piece 212, the first step wall 126 and the second pole piece group 22 are located on the same side of the first pole piece group 21, and the distance between the first step wall 126 and the first inner pole piece 212 is L1, 0mm≤L1≤0.5mm.

[0121] In some embodiments, the surface of the first inner pole piece 212 located at the first portion 211 facing the first step wall is provided with an insulating member 30 to reduce the risk of short circuit of the battery cell 100. In this case, L1 is the distance between the first step wall 126 and the insulating member 30 in the first direction X. The insulating member 30 may be an insulating coating or adhesive tape.

[0122] Illustratively, L1 may be 0 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0123] Along the first direction X, the distance between the first step wall 126 and the first inner pole piece 212 of the first pole piece group 21 closest to the second pole piece group 22 is less than or equal to 0.5 mm, so that the distance between the first step wall 126 and the first pole piece group 21 in the first direction X is small enough to reduce the risk of the first pole piece group 21 shaking in the first accommodating cavity 111 or reduce the degree of shaking of the first pole piece group 21 in the first accommodating cavity 111, alleviate the problem of drop failure, and thus improve the impact resistance and stability of the battery cell 100 when it is dropped. The distance between the first cavity wall and the first pole piece group 21 in the first direction X is small enough to reduce the space waste of the first accommodating cavity 111, which is conducive to improving the energy density of the battery cell 100.

[0124] See also Figure 1 , Fig. 9 , Fig.10 In some embodiments, a first gap Q1 is provided between the first pole piece group 21 and the cavity wall of the first accommodating cavity 111. When viewed along the first direction X, the first gap Q1 extends along the circumference of the first pole piece group 21. The width of the first gap Q1 is W1, 0.01 mm ≤ W 1 ≤1mm.

[0125] The first gap Q1 may be a space between the inner surface of the first side wall 113 and the outer peripheral surface of the negative electrode sheet in the first electrode sheet group 21. The first gap Q1 is a part of the first accommodating cavity 111. 1 is the distance between the inner surface of the first side wall 113 and the outer peripheral surface of the negative electrode in the first electrode group 21. When viewed along the first direction X, the first gap Q1 extends along the circumferential direction of the first electrode group 21, which means that when viewed along the first direction X, the angle of the first gap Q1 around the first electrode group 21 is 360°.

[0126] W1 is only a symbol for representing the width of the first gap Q1 , and it should not be considered that the width of the first gap Q1 at any position is equal, but rather that the width of the first gap Q1 at any position satisfies 0.01 mm to 1 mm.

[0127] For example, W 1 It can be 0.01mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0128] By making the width of the first gap Q1 greater than or equal to 0.01 mm, the risk of the electrode of the first electrode group 21 and the cavity wall of the first accommodating cavity 111 rubbing against each other and puncturing the packaging can be reduced, thereby improving the safety performance of the battery cell 100. The width of the first gap Q1 is greater than or equal to 0.01 mm, which reserves an assembly margin for the first electrode group 21 to enter the shell, reduces the risk of interference between the first electrode group 21 and the cavity wall of the first accommodating cavity 111 during the process of the first electrode group 21 entering the shell, makes it more convenient for the first electrode group 21 to enter the shell, and is conducive to improving the assembly quality of the battery cell 100. The width of the first gap Q1 is less than or equal to 1 mm, so that the distance between the cavity wall of the first accommodating cavity 111 and the outer periphery of the first pole piece group 21 is small enough, reducing the risk of the first pole piece group 21 shaking in the first accommodating cavity 111 or slowing down the shaking degree of the first pole piece group 21 in the first accommodating cavity 111, alleviating the problem of drop failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped, and reducing the space waste of the first accommodating cavity 111, which is conducive to improving the energy density of the battery cell 100. Therefore, 0.01mm≤W 1 ≤1mm, which is beneficial to improving the safety, assembly quality, impact resistance and stability of the battery cell 100 when it is dropped, and improving the energy density of the battery cell 100.

[0129] like Fig.11 As shown, in some embodiments, along the second direction Y, the first pole piece group 21 has a first portion 211 that exceeds the second pole piece group 22, and the second accommodating cavity 121 has a second cavity wall 1231 disposed facing the second pole piece group 22, and the second cavity wall 1231 is located on a side of the second pole piece group 22 close to the first portion 211, and the distance between the second cavity wall 1231 and the second pole piece group 22 is L 2 , 0.01mm≤L 2 ≤1mm.

[0130] The second cavity wall 1231 may be a portion of the second side wall 123. In some embodiments, the second cavity wall 1231 may be a portion where the second side wall 123 and the first step wall 126 are connected.

[0131] The distance L between the second cavity wall 1231 and the second pole piece group 22 2 , which can be the minimum distance between the second cavity wall 1231 and the negative electrode plate of the second electrode plate group 22.

[0132] L 2 It can be 0.01mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0133] By ensuring that the distance between the second cavity wall 1231 and the second electrode assembly 22 along the second direction Y is greater than or equal to 0.01 mm, the risk of the electrode of the second electrode assembly 22 and the cavity wall 1231 rubbing against each other and puncturing the package 10 can be reduced, thereby improving the safety performance of the battery cell 100. It can also provide an assembly margin for the second electrode assembly 22 to enter the shell, thereby reducing the risk of interference between the second electrode assembly 22 and the second cavity wall 1231 during the process of the second electrode assembly 22 entering the shell. This makes it more convenient for the second electrode assembly 22 to enter the shell, and helps to improve the assembly quality of the battery cell 100. By making the distance between the second cavity wall 1231 and the second pole piece group 22 along the second direction Y greater than or equal to 1 mm, the distance between the second cavity wall 1231 and the second pole piece group 22 is small enough to reduce the risk of the second pole piece group 22 shaking in the second accommodating cavity 121 or reduce the degree of shaking of the second pole piece group 22 in the second accommodating cavity 121, thereby alleviating the problem of drop failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped, and reducing the space waste of the second accommodating cavity 121, which is conducive to improving the energy density of the battery cell 100. Therefore, 0.01mm≤L 2 ≤1mm, which is beneficial to improving the safety performance, assembly quality and energy density of the battery cell 100.

[0134] like Fig.12 As shown, in some embodiments, there is a second gap Q2 between the second pole piece group 22 and the cavity wall of the second accommodating cavity 121. When viewed along the first direction X, the second gap Q2 extends along the circumference of the second pole piece group 22. The width of the second gap Q2 is W2, 0.01 mm ≤ W 2 ≤1mm.

[0135] The second gap Q2 may be the space between the inner surface of the second side wall 123 and the outer peripheral surface of the negative electrode sheet in the second electrode sheet group 22, and the second gap Q2 is a part of the second accommodating cavity 121. W2 is the distance between the inner surface of the second side wall 123 and the outer peripheral surface of the negative electrode sheet in the second electrode sheet group 22. In some areas, the distance L2 between the second cavity wall 1231 and the second electrode sheet group 22 is the width of the second gap Q2 in the corresponding area of ​​the second cavity wall 1231.

[0136] When viewed along the first direction X, the second gap Q2 extends along the circumferential direction of the second pole piece set 22, which means that when viewed along the first direction X, the angle of the second gap Q2 around the second pole piece set 21 is 360°.

[0137] W2 is only a symbol for representing the width of the second gap Q2. It should not be considered that the width of the second gap Q2 at any position is equal, but the width of the second gap Q2 at any position satisfies 0.01 mm to 1 mm.

[0138] Illustratively, W2 may be 0.01 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0139] The width of the second gap Q2 is greater than or equal to 0.01 mm, which can reduce the risk of the electrode of the second electrode group 22 and the cavity wall of the second accommodating cavity 121 rubbing against the package 10, thereby improving the safety performance of the battery cell 100. The width of the second gap Q2 is greater than or equal to 0.01 mm, which reserves an assembly margin for the second electrode group 22 to enter the shell, reduces the risk of interference between the second electrode group 22 and the cavity wall of the second accommodating cavity 121 during the process of the second electrode group 22 entering the shell, makes it more convenient for the second electrode group 22 to enter the shell, and is conducive to improving the assembly quality of the battery cell 100. The width of the second gap Q2 is less than or equal to 1mm, so that the distance between the cavity wall of the second accommodating cavity 121 and the outer periphery of the second pole piece group 22 is small enough, reducing the risk of the second pole piece group 22 shaking in the second accommodating cavity 121 or slowing down the shaking degree of the second pole piece group 22 in the second accommodating cavity 121, alleviating the problem of drop failure, thereby improving the impact resistance and stability of the battery cell 100 when it is dropped, and reducing the space waste of the second accommodating cavity 121, which is conducive to improving the energy density of the battery cell 100. Therefore, 0.01mm≤W2≤1mm is conducive to improving the safety, assembly quality, impact resistance and stability of the battery cell 100 when it is dropped, and improving the energy density of the battery cell 100.

[0140] like Fig.13 As shown, a portion of the edge of the first shell 11 is connected to a portion of the edge of the second shell 12 via a bending portion 13 , and the first shell 11 and the second shell 12 are both integrally formed with the bending portion 13 .

[0141] A portion of the edge of the first shell 11 and a portion of the edge of the second shell 12 are connected through the bending portion 13 , which means that before the battery cell 100 is packaged, a portion of the edge of the first shell 11 and a portion of the edge of the second shell 12 are connected through the bending portion 13 .

[0142] During the assembly of the battery cell 100 , the first shell 11 can be folded relative to the second shell 12 around the bending portion 13 , or the second shell 12 can be folded relative to the first shell 11 around the bending portion 13 , so that the first shell 11 and the second shell 12 are arranged opposite to each other in the first direction X.

[0143] Since the first shell 11 and the second shell 12 are integrally formed with the bending portion 13, the first shell 11 and the second shell 12 do not need to be sealed at the corresponding positions of the bending portion 13 or the sealing level can be reduced, which is beneficial to simplify the packaging process of the battery cell 100 and reduce the difficulty of the battery cell 100.

[0144] Since the first shell 11 and the second shell 12 are connected by the bending portion 13, and the first shell 11 and the second shell 12 are both integrally formed with the bending portion 13, no additional connection processing is required between the first shell 11 and the bending portion 13, and between the second shell 12 and the bending portion 13. Therefore, the first shell 11 and the second shell 12 are both integrally formed with the bending portion 13, and the weak connection parts of the packaging 10 of the battery cell 100 can be reduced, which is beneficial for the packaging 10 of the battery cell 100 to have better strength and improve the safety performance and reliability of the battery cell 100.

[0145] Please continue to refer to Fig.13 In some embodiments, the first housing 11 includes a plurality of first edges 116, which are connected in sequence to form an edge of the first housing 11. The first housing 11 includes a plurality of second edges 127, which are connected in sequence to form an edge of the second housing 12. Some of the first edges 116 and some of the second edges 127 are connected by the bending portion 13.

[0146] For example, Fig.13 As shown, one of the first edge portions 116 among the plurality of first edge portions 116 and one of the second edge portions 127 among the plurality of second edge portions 127 are connected by a bending portion 13 .

[0147] By connecting one of the multiple first edge portions 116 portions and one of the multiple second edge portions 127 portions through the bending portion 13, it is beneficial to simplify the packaging process of the battery cell 100 and reduce the packaging difficulty, and it is also beneficial to reserve a larger entrance for the electrode assembly 20 to enter the shell before the first shell 11 and the second shell 12 are packaged, so that the electrode assembly 20 is easy to be placed in the space between the first shell 11 and the second shell 12, reducing the difficulty of the electrode assembly 20 entering the shell and improving the efficiency of shell entry.

[0148] In other embodiments, Fig.14 As shown, the first shell 11 and the second shell 12 are separately arranged and connected.

[0149] It should be noted that the first shell 11 and the second shell 12 are separately arranged and connected, which means that before the battery cell 100 is packaged, the first shell 11 and the second shell 12 are independent of each other and have no connection relationship, and the first shell 11 and the second shell 12 are connected after the packaging is completed.

[0150] Because the first shell 11 and the second shell 12 are independent of each other before packaging, the distance between the first shell 11 and the second shell 12 in the first direction X can be adjusted to accommodate electrode assemblies 20 of different sizes in the first direction X.

[0151] like Fig.15 , Fig.16 As shown, in the first direction X, the first shell 11 has a first surface 117 closest to the second shell 12, and the second shell 12 has a second surface 128 closest to the first shell 11. The first accommodating cavity 111 is recessed from the first surface 117 in a direction away from the second shell 12. The second accommodating cavity 121 is recessed from the second surface 128 in a direction away from the first shell 11. If the distances between the first surface 117 and the second surface 128 in the first direction X are different, then the distances between the first shell 11 and the second shell 12 in the first direction X are different, so that the space defined by the first shell 11 and the second shell 12 can accommodate electrode assemblies 20 with different sizes in the first direction X. Figure 7 As shown, the first surface 117 and the second surface 128 are in contact with each other. Fig.15 In the embodiment, a seal 40 is provided between the first surface 117 and the second surface 128. The seal 40 makes the distance between the first shell 11 and the second shell 12 in the first direction X larger. Therefore, Figure 8 The package 10 shown in FIG. Fig.16 The package 10 shown in FIG. 1 may accommodate an electrode assembly 20 having a larger size in the first direction X.

[0152] Therefore, by separately arranging and connecting the first shell 11 and the second shell 12, it is convenient to match the first shell 11 and the second shell 12 with the electrode assemblies 20 of different sizes in the first direction X, so that the package 10 formed by the first shell 11 and the second shell 12 has better versatility.

[0153] In some embodiments, the shape of the first accommodating cavity 111 can match the shape of the first electrode group 21. For example, if the shape of the first electrode group 21 is a rectangle, the shape of the first accommodating cavity 111 can be a rectangle; if the shape of the first electrode group 21 is an arc bent around an axis extending in the first direction X, the shape of the first accommodating cavity 111 can be an arc bent around an axis extending in the first direction X.

[0154] In some embodiments, the shape of the second accommodating cavity 121 can match the shape of the second pole piece group 22. For example, if the shape of the second pole piece group 22 is a rectangle, the shape of the second accommodating cavity 121 can be a rectangle; if the shape of the second pole piece group 22 is an arc bent around an axis extending in the first direction X, the shape of the second accommodating cavity 121 can be an arc bent around an axis extending in the first direction X.

[0155] For example, Fig.13 , Fig.14 As shown, the first accommodating cavity 111 and the second accommodating cavity 121 are both rectangular in shape. Fig.17 , Fig.18As shown, the first accommodating cavity 111 is rectangular in shape, and the second accommodating cavity 121 is U-shaped in shape.

[0156] An embodiment of the present application further provides an electrical device, and the electrical device includes the battery cell 100 provided in any of the above embodiments.

[0157] The battery cell 100 provides electric energy for the electric device to operate.

[0158] The battery cell 100 provided in any of the above embodiments has good safety performance, good impact resistance and stability when dropped, and high energy density, which is beneficial to improving the power safety performance and power reliability of the electrical equipment powered by the battery cell 100.

[0159] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes.

Claims

1. A battery cell, characterized in that: include: An electrode assembly, comprising a first pole piece group and a second pole piece group, wherein the first pole piece group and the second pole piece group are stacked along a first direction, and along a second direction, the length of the first pole piece group is greater than the length of the second pole piece group, and the second direction is perpendicular to the first direction; A first shell and a second shell are arranged opposite to each other along the first direction, a first accommodating cavity is arranged on a surface of the first shell facing the second shell, and a second accommodating cavity is arranged on a surface of the second shell facing the first shell, along the second direction, the length of the first accommodating cavity is greater than the length of the second accommodating cavity, along the first direction, at least a part of the first pole piece group is accommodated in the first accommodating cavity, and at least a part of the second pole piece group is accommodated in the second accommodating cavity.

2. The battery cell according to claim 1, characterized in that: Along the first direction, a first protrusion is formed on a surface of the first shell facing away from the second shell and corresponding to the first accommodating cavity; and / or a second protrusion is formed on a surface of the second shell facing away from the first shell and corresponding to the second accommodating cavity.

3. The battery cell according to claim 1, characterized in that: A portion of the edge of the first shell is connected to a portion of the edge of the second shell via a bending portion, and the first shell and the second shell are both integrally formed with the bending portion.

4. The battery cell according to claim 3, characterized in that: The edge of the first shell includes a plurality of first edge portions, the edge of the second shell includes a plurality of second edge portions, and one of the plurality of first edge portions and one of the plurality of second edge portions are connected via the bending portion.

5. The battery cell according to claim 1, characterized in that: The first shell and the second shell are separately arranged and connected.

6. The battery cell according to claim 1, characterized in that: The first accommodating cavity forms a first opening on the surface of the first shell facing the second shell, and the second accommodating cavity forms a second opening on the surface of the second shell facing the first shell. Along the second direction, one end of the first opening is flush with one end of the second opening, and the first opening exceeds the other end of the second opening.

7. The battery cell according to claim 1, characterized in that: The first accommodating cavity forms a first opening on the surface of the first shell facing the second shell, and the second accommodating cavity forms a second opening on the surface of the second shell facing the first shell. Along the third direction, two ends of the first opening are respectively flush with two ends of the second opening, and the first direction, the second direction and the third direction are perpendicular to each other.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The first shell includes a first sealing portion surrounding the first accommodating cavity, and the second shell includes a second sealing portion surrounding the second accommodating cavity, and the first sealing portion and the second sealing portion are sealingly connected.

9. The battery cell according to any one of claims 1 to 7, characterized in that: The first accommodating cavity is stamped and formed in the first shell, and the second accommodating cavity is stamped and formed in the second shell.

10. The battery cell according to any one of claims 1 to 7, characterized in that: Along the first direction, the first pole piece group is completely accommodated in the first accommodation cavity, and the second pole piece group is completely accommodated in the second accommodation cavity.

11. The battery cell according to any one of claims 1 to 7, characterized in that: Along the first direction, the first pole piece group has a first inner pole piece closest to the second pole piece group, and the second shell has a first step wall facing the first inner pole piece and closest to the first inner pole piece, the first step wall and the second pole piece group are located on the same side of the first pole piece group, and the distance between the first step wall and the first inner pole piece is L1, 0mm≤L1≤0.5mm.

12. The battery cell according to any one of claims 1 to 7, characterized in that: A first gap is provided between the first pole piece group and the cavity wall of the first accommodating cavity. When viewed along the first direction, the first gap extends along the circumference of the first pole piece group. The width of the first gap is W1, and 0.01 mm≤W1≤1 mm.

13. The battery cell according to any one of claims 1 to 7, characterized in that: Along the second direction, the first pole piece group has a first part that exceeds the second pole piece group, and the second accommodating cavity has a second cavity wall arranged facing the second pole piece group, and the second cavity wall is located on the side of the second pole piece group close to the first part, and the distance between the second cavity wall and the second pole piece group is L2, 0.01mm≤L2≤1mm.

14. The battery cell according to any one of claims 1 to 7, characterized in that: A second gap is provided between the second pole piece group and the cavity wall of the second accommodating cavity. When viewed along the first direction, the second gap extends along the circumference of the second pole piece group. The width of the second gap is W2, and 0.01 mm≤W2≤1 mm.

15. The battery cell according to any one of claims 1 to 7, characterized in that: The battery cell is a soft-pack battery cell.

16. An electrical equipment, characterized in that: Comprising the battery cell according to any one of claims 1-15.

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