Battery monomer, battery and electric device

Abstract

The utility model relates to the technical field of batteries, and discloses a single battery, a battery and an electric device. The electrode assembly is arranged in the shell, and the electrode assembly is provided with an expandable surface; and the buffering piece is arranged in the shell and arranged on the expandable face in an attached mode, the buffering piece comprises a buffering main body part and a sealing part, and the buffering main body part is wrapped with the sealing part. According to the utility model, the buffer piece can support the expandable surface when the electrode assembly expands and deforms, so that the deformation of the electrode assembly is reduced, and the probability of keeping a good interface of the electrode assembly is improved. The buffer piece comprises the buffer main body part and the sealing part, and the sealing part wraps the buffer main body part, so that the buffer main body part can be sealed, the buffer main body part is separated from the electrolyte in the shell, the probability of corrosion of the buffer main body part is reduced, and the reliability of the single battery can be improved; and the service life of the battery monomer is prolonged.

Description

Technical Field

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

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, batteries, as the power source of electric vehicles, play an irreplaceable and important role. The battery consists of a box and multiple battery cells contained in the box. Among them, batteries, as the core components of new energy vehicles, have high requirements in terms of reliability. Therefore, how to further improve the reliability of batteries has become one of the problems that need to be solved urgently. Utility Model Content

[0003] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell, thereby facilitating improving the reliability of the battery and the electrical device.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a shell; an electrode assembly, the electrode assembly is disposed in the shell, and the electrode assembly is provided with an expandable surface; a buffer component, the buffer component is disposed in the shell and is fitted on the expandable surface, the buffer component includes a buffer body portion and a sealing portion, and the sealing portion is wrapped around the buffer body portion.

[0005] In the above technical solution, the buffer can support the expandable surface when the electrode assembly expands and deforms, which is beneficial to reduce the deformation of the electrode assembly and improve the probability of the electrode assembly maintaining a good interface. In addition, by configuring the buffer to include a buffer body and a sealing part, the sealing part is wrapped around the buffer body, which can seal the buffer body, isolate the buffer body from the electrolyte in the shell, reduce the probability of corrosion of the buffer body, improve the reliability of the buffer body, and help extend the service life of the buffer body, so that the buffer can maintain a good support effect on the electrode assembly for a long time, which can improve the reliability of the electrode assembly and extend the service life of the electrode assembly, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0006] In some embodiments of the present application, the buffer body is provided with multiple side portions, and the multiple side portions are arranged along the circumference of the buffer body. The buffer member includes a gas accommodating portion, which is provided on at least one side portion and can exchange gas with the buffer body.

[0007] In the above technical solution, the gas containing portion can accommodate the gas squeezed out when the buffer main body is compressed, and can provide the required gas pressure when the buffer main body is restored to its original state. In this way, the squeezed gas in the buffer main body can be prevented from reacting with the electrolyte, and the probability of the buffer main body absorbing the electrolyte can be reduced, thereby further reducing the probability of the buffer main body being corroded, which is beneficial to improving the reliability of the buffer main body.

[0008] In some embodiments of the present application, the sealing portion is provided with a first extending portion extending out of the buffer body portion, and the first extending portion forms a gas accommodating portion.

[0009] In the above technical solution, the gas accommodating portion is formed by extending the sealing portion out of the first extension portion of the buffer main body portion, so that the gas accommodating portion and the sealing portion can be one component. Thus, the gas accommodating portion can be formed while the sealing portion is provided on the buffer main body portion, which is beneficial to reducing the molding difficulty of the gas accommodating portion, and can simplify the manufacturing process of the buffer component and reduce the manufacturing cost.

[0010] In some embodiments of the present application, the electrode assembly includes a connected electrode main body and a conductive part, the electrode main body is provided with a first surface and an expandable surface, the first surface is arranged adjacent to the expandable surface, the conductive part is arranged on the first surface, and the gas accommodating part is inclined relative to the buffer main body and is located on the side of the expandable surface close to the first surface.

[0011] In the above technical solution, the gas accommodating portion is inclined relative to the buffer main body and is located on the side of the expandable surface close to the first surface. As a result, the gas accommodating portion can be arranged close to the conductive portion, and the space around the conductive portion can be fully utilized to arrange the gas accommodating portion, which is beneficial to improving the compactness of the internal structure of the battery cell. No additional space is required to set up the gas accommodating portion. While improving the reliability of the buffer main body, the battery cell has a higher volume energy density.

[0012] In some embodiments of the present application, there is only one first surface, which is disposed on the top of the electrode body. In this technical solution, a conductive portion is disposed on the top of the electrode body, and a gas containing portion is also disposed on the top of the electrode assembly. A battery cell adopting this structure can be provided with an electrode terminal on the top, which facilitates the installation and connection of the battery cell and can make the battery cell have higher reliability.

[0013] In some embodiments of the present application, there are at least two first faces, and at least one first face is provided with a gas accommodating portion. In this technical solution, there are at least two first faces of the electrode body, so there can also be at least two conductive portions, so that the shell can be provided with multiple electrode terminals, that is, the battery cell in this solution can constitute a structure in which electrode terminals are provided on multiple faces. By providing a gas accommodating portion on at least one first face, the reliability of the battery cell of this structure can be improved.

[0014] In some embodiments of the present application, there are two first surfaces, which are located at opposite ends of the electrode body, and the two first surfaces are provided with gas accommodating parts. In this technical solution, the first surfaces are provided at opposite ends of the electrode body, so the conductive parts can be provided at opposite ends of the electrode body, and the electrode terminals are provided at opposite ends of the shell, that is, the battery cell in this solution can constitute a structure in which the electrode terminals are provided at two opposite end faces, and the reliability of the battery cell of this structure can be improved by providing gas accommodating parts at the two first surfaces.

[0015] In some embodiments of the present application, the first surface is located at least at one end of the electrode body in the first direction, and in the first direction, one end of the buffer body close to the first surface extends out of the first surface or is flush with the first surface.

[0016] In the above technical solution, by extending one end of the buffer body close to the first surface in the first direction out of the first surface or being flush with the first surface, the buffer body can completely cover the expandable surface in the first direction, which can provide better support for the expandable surface and reduce the probability of wrinkling at the edge of the electrode assembly in the first direction and causing a poor interface, which is beneficial to improving the reliability of the electrode assembly and further improving the reliability of the battery cell.

[0017] In some embodiments of the present application, in the first direction, the size of the electrode body is W, and the size of the buffer body is H1, wherein W+1mm≤H1≤W+3mm.

[0018] In the above technical solution, by setting the relationship between the dimension W of the electrode main body in the first direction and the dimension H1 of the buffer main body in the first direction within the above range, the buffer main body and the expandable surface can satisfy the assembly error while enhancing the supporting effect of the buffer main body on the expandable surface. It is also beneficial to reduce the space required for the buffer main body, so that the battery cell has a higher volume energy density while having higher reliability.

[0019] In some embodiments of the present application, the electrode body is provided with a second surface, which is arranged at both ends of the second direction of the electrode body and is connected to the expandable surface and the first surface. The second surface is an arc surface, wherein the second direction and the first direction are arranged at an angle. In the second direction, the end of the buffer body close to the second surface extends out of the expandable surface, or the end of the buffer body close to the second surface is flush with the edge where the expandable surface and the second surface are connected.

[0020] In the above technical solution, the buffer body can fully cover the expandable surface at both ends of the second direction, which can provide better support for the expandable surface, reduce the probability of a poor interface appearing at the edge of the electrode assembly in the second direction, and further improve the reliability of the electrode assembly, thereby improving the reliability of the battery cell.

[0021] In some embodiments of the present application, in the second direction, the size of the expandable surface is L, and the size of the buffer body is H2, wherein L+1mm≤H2≤L+4mm.

[0022] In the above technical solution, by setting the relationship between the size L of the expandable surface in the second direction and the size H2 of the buffer body in the second direction within the above range, the buffer body and the expandable surface can meet the assembly error, and the buffer body can have a high probability of fully covering the expandable surface, thereby enhancing the support of the buffer body to the expandable surface. It is also beneficial to reduce the space required for the buffer body, so that the battery cell has a higher volume energy density while having higher reliability.

[0023] In some embodiments of the present application, the electrode assembly is a winding core assembly, which is flat and has a central gap formed in the middle. The electrode assembly is provided with a second surface, and the second surface and the expandable surface are located on the peripheral side of the central gap. The expandable surface is a plane, and the second surface is an arc surface and is connected to the expandable surface, wherein the orthographic projection of the central gap on the expandable surface is located within the orthographic projection of the buffer body on the expandable surface.

[0024] In the above technical solution, the buffer body does not need to fully cover the expandable surface, but only needs to fully cover the area where the central gap on the expandable surface is located. Since in the winding core assembly structure, the area where the central gap on the expandable surface is located is the area where the force is most concentrated when the pole piece expands, and it is also the area with a higher probability of expansion and deformation, so by covering the buffer body within this area, it can play a better supporting role, reduce the probability of wrinkling of the electrode assembly and causing a bad interface, and also help to reduce the size of the buffer body and reduce costs. In addition, the above solution can also reduce the volume of the buffer, so that there is more space in the shell for filling the electrolyte, which is beneficial to improve the performance of the battery cell.

[0025] In some embodiments of the present application, the electrode assembly has a first direction, a second direction and a third direction, a central gap penetrates the electrode assembly along the first direction, the second surface is located at both ends of the second direction of the electrode assembly, and the expandable surface is located at both ends of the third direction of the electrode assembly; in the first direction, the size of the electrode assembly is W, and the size of the buffer body is H1, wherein W+1mm≤H1≤W+3mm; in the second direction, the size of the central gap is N, and the size of the buffer body is H2, wherein N+1mm≤H2≤N+3mm.

[0026] In the above technical solution, the buffer body has a good supporting effect on the expandable surface and can have a certain assembly error range, which is beneficial to improve the assembly qualification rate between the buffer body and the electrode assembly, and is also beneficial to reduce the material used in the buffer body, reduce costs, and reduce the probability of the buffer body occupying a large space, which is beneficial to make the battery cell have higher reliability and higher volume energy density.

[0027] In some embodiments of the present application, a buffer is disposed between the expandable surface and the inner side surface of the shell.

[0028] In this technical solution, the two relative surfaces of the buffer are respectively attached to the expandable surface and the inner side surface of the outer shell. When the expandable surface of the electrode assembly expands and deforms, due to the high strength of the outer shell, it can better support the expandable surface by acting on the buffer, which is beneficial to further reduce the probability of wrinkling and forming a bad interface on the expandable surface, thereby further improving the reliability of the battery cell.

[0029] In some embodiments of the present application, there are at least two electrode assemblies, and a buffer is provided between the expandable surfaces of at least one group of two adjacent electrode assemblies; and / or a buffer is provided between the expandable surface of the electrode assembly and the inner side surface of the shell.

[0030] In the above technical solution, in the structure where the battery cell includes at least two electrode assemblies, the above solution can further enhance the supporting effect of the buffer component on the at least two electrode assemblies, thereby further reducing the probability of a bad interface in the electrode assembly, which is beneficial to improving the reliability within multiple electrode assemblies, and further improving the reliability of the battery cell.

[0031] In some embodiments of the present application, the electrode assembly is provided with a plurality of surfaces in addition to the expandable surface, and the area of ​​the expandable surface is larger than the areas of the remaining surfaces.

[0032] In the above scheme, the expandable surface may refer to the surface with the largest area in the electrode assembly. When the electrode assembly expands and deforms, it is more likely to concentrate on the expandable surface. The buffer component is supported on the surface with the largest area of ​​the electrode assembly. The buffer component has a better supporting effect on the electrode assembly, which is beneficial to further reduce the probability of a bad interface in the electrode assembly and improve the reliability of the battery cell.

[0033] In a second aspect, an embodiment of the present application further provides a battery, comprising the battery cell described above.

[0034] In the above technical solution, since the battery cell has a relatively high reliability, the reliability of the battery can be improved, which is beneficial to improving the performance of the battery and extending the service life of the battery.

[0035] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the battery cell as described above, or the battery as described above.

[0036] In the above technical solution, since the battery cells and the battery have high reliability, the reliability of the electrical device can be improved, which is beneficial to improving the performance of the electrical device and extending the service life of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0039] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0040] Figure 3 An exploded view of a battery cell provided in some embodiments of the present application;

[0041] Figure 4 Explosive decomposition of a partial structure of a battery cell provided in some embodiments of the present application Figure 1 ;

[0042] Figure 5 A schematic diagram of assembling an electrode assembly and a buffer member provided in some embodiments of the present application;

[0043] Figure 6 Explosive decomposition of a partial structure of a battery cell provided in some embodiments of the present application Figure 2 ;

[0044] Figure 7 A schematic diagram of the internal structure of a battery cell provided in some embodiments of the present application;

[0045] Figure 8 A schematic diagram of a partial internal structure of a battery cell provided in some embodiments of the present application;

[0046] Fig. 9 A schematic diagram of a partial internal structure of a battery cell provided in another embodiment of the present application;

[0047] Fig.10 A schematic diagram of a partial internal structure of a battery cell provided in yet another embodiment of the present application;

[0048] Fig.11 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application.

[0049] Icons: 1000, vehicle; 100, battery; 10, casing; 11, first casing body; 12, second casing body; 20, battery cell; 21, casing; 201, electrode terminal; 211, shell; 212, cover plate; 22, electrode assembly; 2201, expandable surface; 2202, first surface; 2203, second surface; 2204, center gap; 221, electrode body; 222, conductive part; 23, buffer; 231, buffer body; 2311, side; 232, sealing part; 233, gas containing part; 200, controller; 300, motor; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0050] 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 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, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0052] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0053] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0055] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0056] The term "plurality" used in the present application refers to two or more (including two).

[0057] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0058] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells or multiple battery modules. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0059] The battery cell includes a shell, an electrode assembly and an electrolyte, and the shell is used to contain the electrode assembly and the electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as a positive electrode ear. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can 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. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector not coated with the negative electrode active material layer protrudes from the negative electrode current collector coated with the negative electrode active material layer. The negative electrode current collector not coated with the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure that a large current passes without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together.

[0060] The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a winding structure or a stacked structure, but the embodiments of the present application are not limited thereto.

[0061] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, batteries, as the power source of electric vehicles, play an irreplaceable and important role. The battery consists of a box and multiple battery cells contained in the box. Among them, batteries, as the core components of new energy vehicles, have high requirements in terms of reliability. Therefore, how to further improve the reliability of batteries has become one of the problems that need to be solved urgently.

[0062] In a general battery cell, the thickness of the electrode sheet will expand and contract in a breathing-like reciprocating change during the charge and discharge process of the electrode assembly, resulting in a cumulative increase in the thickness of the electrode sheet, which in turn leads to an increase in the thickness of the electrode assembly and an increase in the expansion force within the electrode assembly. In order to alleviate the problem of the electrode assembly life accelerating due to the increase in the expansion force within the electrode assembly exceeding the boundary, it is necessary to reserve thickness expansion space in the outer shell of the battery cell. However, the thickness expansion space reserved in the outer shell will cause the electrode sheet to wrinkle under the tension of the expansion process, increasing the probability of poor interface, thereby affecting the reliability of the electrode assembly, which will also affect the reliability of the battery cell, and thus the reliability of the battery and the electrical device.

[0063] Based on the above considerations, in order to solve the problem that the thickness of the electrode assembly increases cumulatively due to expansion during the charge and discharge process of the battery cell, thereby affecting the reliability of the battery cell, the present application designs a battery cell, including: a shell, an electrode assembly and a buffer; the electrode assembly is arranged in the shell, and the electrode assembly is provided with an expandable surface; the buffer is arranged in the shell and is fitted on the expandable surface, the buffer includes a buffer body and a sealing part, and the sealing part is wrapped around the buffer body.

[0064] In a battery cell of this structure, the buffer can support the expandable surface when the electrode assembly expands and deforms, thereby reducing the deformation of the expandable surface, which is beneficial to improving the probability of the electrode assembly maintaining a good interface. In addition, by configuring the buffer to include a buffer body and a sealing portion, the sealing portion is wrapped around the buffer body, which can play a high sealing role on the buffer body, thereby isolating the buffer body from the electrolyte in the shell, reducing the probability of the buffer body contacting the electrolyte and corroding, which is beneficial to extending the service life of the buffer body, and further enabling the buffer to maintain a good supporting effect on the electrode assembly for a long time, which can improve the reliability of the battery cell.

[0065] The battery cells disclosed in the embodiments of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. A power supply system having the battery disclosed in the present application and the like to form the electrical device can be used, which is conducive to expanding the application scope of the battery cells.

[0066] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0067] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0068] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0069] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0070] Please refer to Figure 2 , Figure 2 The structural exploded diagram of the battery 100 provided for some embodiments of the present application. The battery 100 includes a box body 10 and a plurality of battery cells 20, and the battery cells 20 are used to be accommodated in the box body 10. Among them, the box body 10 is used to provide an assembly space for the battery cells 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, and the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20. The second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define the assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0071] In the battery 100, multiple battery cells 20 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that multiple battery cells 20 are connected in series and in parallel. Multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid connection, and then the whole formed by multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection, and then multiple battery modules are connected in series, in parallel, or in a hybrid connection to form a whole, and accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between multiple battery cells 20.

[0072] Please refer to Figure 2 , Figure 2 A partial structural diagram of a battery 100 provided in some embodiments of the present application. The battery 100 includes multiple rows of battery cells 20, which are arranged along the length direction of the box 10, and each row of battery cells 20 includes multiple battery cells 20 arranged along the width direction of the box 10, or multiple rows of battery cells 20 are arranged along the width direction of the box 10, and each row of battery cells 20 includes multiple battery cells 20 arranged along the length direction of the box 10.

[0073] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular or in other shapes. Figure 2 In the figure, the battery cell 20 is in the shape of a rectangular parallelepiped.

[0074] According to some embodiments of the present application, referring to Figure 3 , Figure 4 and Fig.11 In the first aspect, the embodiment of the present application provides a battery cell 20, including a housing 21, an electrode assembly 22 and a buffer 23. The electrode assembly 22 is disposed in the housing 21, and the electrode assembly 22 is provided with an expandable surface 2201. The buffer 23 is disposed in the housing 21 and is fitted on the expandable surface 2201. The buffer 23 includes a buffer body 231 and a sealing part 232, and the sealing part 232 is wrapped in the buffer body 231.

[0075] The shell 21 may refer to the external packaging component of the battery cell 20, and is a closed shell structure, which is used to protect the internal structure of the battery cell 20 and prevent the external environment from affecting the performance of the battery cell 20. The shell 21 may include a shell 211 and a cover plate 212 covering the open shell 211. The shell 21 may also include but is not limited to metal materials, plastic materials, composite materials, etc. Exemplarily, the shell 21 may be an aluminum shell. Among them, the shell 21 may include but is not limited to a cylindrical shell, a rectangular shell, and a cube, etc.

[0076] The electrode assembly 22 may refer to the core component of the battery cell 20, which is responsible for the chemical reaction during the battery charging and discharging process, thereby generating electrical energy. The electrode assembly 22 may include a positive electrode sheet, a negative electrode sheet, and a separator. The separator is arranged between the positive electrode sheet and the negative electrode sheet to form a stacked structure. The electrode assembly 22 may include multiple stacked structures. The electrode assembly 22 may also be a battery cell structure without a negative electrode, that is, the electrode assembly 22 may have a negative electrode current collector but no negative electrode sheet.

[0077] The expandable surface 2201 may refer to a surface in the electrode assembly 22 that can expand and bulge outward, that is, during the charge and discharge process of the electrode assembly 22 , the cumulative increase in the thickness of the electrode sheet may occur on the expandable surface 2201 .

[0078] There may be one or more expandable surfaces 2201. That is, there may be one expandable surface 2201, and the expansion and swelling of the electrode assembly 22 may occur on one surface; there may also be multiple expandable surfaces 2201, and the expansion and swelling of the electrode assembly 22 may occur on multiple surfaces.

[0079] The expandable surface 2201 may be at least one surface in at least one of the first direction X, the second direction Y, and the third direction Z of the electrode assembly 22. It is understood that the expandable surface 2201 may be one surface or two surfaces in the first direction X of the electrode assembly 22; the expandable surface 2201 may also be one surface or two surfaces in the second direction Y of the electrode assembly 22; the expandable surface 2201 may also be one surface or two surfaces in the third direction Z of the electrode assembly 22; or, the expandable surface 2201 may also be multiple surfaces in multiple directions of the electrode assembly 22. For example, referring to Figure 3 The expandable surface 2201 may be a surface of the electrode assembly 22 in the third direction Z. In this embodiment, the third direction Z may be the thickness direction of the electrode assembly 22 .

[0080] The buffer body 231 may refer to a component that can be compressed under force and return to its original shape after the force is lost. For example, the buffer body 231 may refer to a buffer component with a compressible buffer layer. The buffer body 231 may be in the shape of a flat plate. The buffer body 231 may also include a plurality of long strips, and the plurality of long strips may be spaced apart. Among them, the buffer body 231 may include but is not limited to foaming materials such as silicone rubber foam, silicone foam, foamed polyurethane, foamed polypropylene, foamed polyethylene, and silica aerogel.

[0081] The sealing part 232 may refer to a material or component wrapped in the buffer body part 231, which is used to isolate the buffer body part 231 from the external environment. In other words, the buffer body part 231 can be wrapped around the sealing part 232, so that the buffer body part 231 is separated from the electrolyte in the shell 21, and the electrolyte is prevented from entering the buffer body part 231. Among them, the sealing part 232 can be but is not limited to a coating, a film, a shell part, etc. coated on the buffer body part 231. The sealing part 232 may include but is not limited to corrosion-resistant plastics such as PET (polyethylene terephthalate) and PC (polycarbonate).

[0082] In the above embodiment, when the electrode assembly 22 is deformed by expansion and bulging on the expandable surface 2201, since the buffer 23 is fitted on the expandable surface 2201, the other side of the buffer 23 away from the expandable surface 2201 can be supported on the shell 21 or other components inside the shell 21, so the buffer 23 can play a certain supporting role on the expandable surface 2201, and the deformation degree of the expandable surface 2201 can be reduced through the supporting force, and the probability of the expandable surface 2201 having a bad interface is reduced, which is conducive to maintaining a good interface for the electrode assembly 22. In addition, since the buffer 23 is placed on the outside of the electrode assembly 22, it can also reduce the occupation of the internal space of the electrode assembly 22, which is conducive to saving the space inside the electrode assembly 22 and improving the energy density of the electrode assembly 22.

[0083] Since the buffer component 23 is located inside the outer shell 21, and the electrolyte is filled between the outer shell 21 and the electrode assembly 22, the sealing portion 232 is wrapped around the buffer main body 231 to prevent the buffer main body 231 from contacting the electrolyte. This can also reduce the probability of corrosion of the buffer main body 231. The buffer component 23 can remain in a stable state for a long time, thereby maintaining normal operation for a long time, which is beneficial to extending the service life of the buffer component 23 and reducing the probability of affecting the electrode assembly 22 due to failure of the buffer component 23. As a result, the electrode assembly 22 can have higher reliability and a longer service life.

[0084] Secondly, since the probability of corrosion of the buffer body 231 is relatively low and the service life is relatively long, the frequency of repairing or replacing the buffer body 231 can be reduced, thereby reducing the maintenance cost.

[0085] In the above technical solution, the buffer 23 can support the expandable surface 2201 when the electrode assembly 22 expands and deforms, which is beneficial to reduce the deformation of the electrode assembly 22 and improve the probability of the electrode assembly 22 maintaining a good interface. In addition, by configuring the buffer 23 to include a buffer body 231 and a sealing portion 232, the sealing portion 232 is wrapped in the buffer body 231, which can seal the buffer body 231, isolate the buffer body 231 from the electrolyte in the shell 21, reduce the probability of corrosion of the buffer body 231, improve the reliability of the buffer body 231, and help extend the service life of the buffer body 231, so that the buffer 23 can maintain a good support effect on the electrode assembly 22 for a long time, which can improve the reliability of the electrode assembly 22 and extend the service life of the electrode assembly 22, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0086] In some embodiments of the present application, reference Figure 4 and Figure 6 The buffer body 231 is provided with a plurality of side portions 2311 , and the plurality of side portions 2311 are arranged along the circumference of the buffer body 231 . The buffer member 23 includes a gas accommodating portion 233 , and the gas accommodating portion 233 is provided on at least one side portion 2311 and can exchange gas with the buffer body 231 .

[0087] The buffer body 231 may be a flat plate-shaped component, and the side portion 2311 may refer to the end portion where the circumferential edge of the buffer body 231 is located. Figure 4 and Figure 6 The buffer body portion 231 may be provided with two side portions 2311 in the second direction Y and a side portion 2311 in the first direction X.

[0088] The gas containing part 233 may refer to a cavity structure that can be used to contain gas. The gas containing part 233 may be, but is not limited to, a part made of a softer material or a part made of a harder material, wherein the softer material may include, but is not limited to, rubber, ethylene-vinyl acetate copolymer, etc. For example, the gas containing part 233 may be an air bag or an air bag.

[0089] In this embodiment, the gas receiving portion 233 may be provided on one side portion 2311, so as to exchange gas with the buffer body portion 231 at one side of the buffer body portion 231. The gas receiving portion 233 may also be provided on two or more side portions 2311, so as to exchange gas at multiple positions of the buffer body portion 231, thereby improving the working efficiency of the buffer body portion 231.

[0090] In the above technical solution, the gas containing portion 233 can accommodate the gas squeezed out when the buffer main body 231 is compressed, and can provide the required gas pressure when the buffer main body 231 is restored to its original state. In this way, the gas squeezed out of the buffer main body 231 can be prevented from reacting with the electrolyte, and the probability of the buffer main body 231 absorbing the electrolyte can be reduced, thereby further reducing the probability of the buffer main body 231 being corroded, which is beneficial to improving the reliability of the buffer main body 231.

[0091] In some embodiments of the present application, the sealing portion 232 is provided with a first extending portion extending out of the buffer body portion 231 , and the first extending portion forms a gas accommodating portion 233 .

[0092] The first extension portion may refer to a portion of the sealing portion 232 extending out of the side portion 2311 of the buffer body portion 231. For example, the sealing portion 232 may be a soft film covering the surface of the buffer body portion 231, one end of the soft film extending out of the buffer body portion 231 to form an air bag, which is the gas containing portion 233.

[0093] In the above technical solution, the gas accommodating portion 233 is formed by extending the sealing portion 232 out of the first extension portion of the buffer main body portion 231, so that the gas accommodating portion 233 and the sealing portion 232 can be one component. Therefore, the gas accommodating portion 233 can be formed while the sealing portion 232 is provided on the buffer main body portion 231, which is beneficial to reduce the molding difficulty of the gas accommodating portion 233, and can simplify the manufacturing process of the buffer component 23 and reduce the manufacturing cost.

[0094] In some embodiments of the present application, reference Figure 3 and Figure 4 The electrode assembly 22 includes a connected electrode main body 221 and a conductive part 222. The electrode main body 221 is provided with a first surface 2202 and an expandable surface 2201. The first surface 2202 is arranged adjacent to the expandable surface 2201. The conductive part 222 is arranged on the first surface 2202. The gas accommodating part 233 is inclined relative to the buffer main body 231 and is located on the side of the expandable surface 2201 close to the first surface 2202.

[0095] The electrode body 221 may refer to a component including a positive electrode sheet, a negative electrode sheet, and a separator.

[0096] The conductive portion 222 may refer to a conductive component extending from the positive electrode sheet and the negative electrode sheet, and is used to electrically connect the electrode terminal 201 on the housing 21. The electrode terminal 201 may refer to a conductive structure or component in the battery cell 20 used to connect other battery cells 20 or electrical components. Specifically, the electrode terminal 201 on the positive electrode sheet can be understood as a positive electrode ear, and the electrode terminal 201 on the negative electrode sheet can be understood as a negative electrode ear.

[0097] The first surface 2202 may refer to a surface on the electrode body 221 that is connected to the expandable surface 2201 and is used to provide an installation position for the conductive portion 222 .

[0098] In the above technical solution, the gas accommodating portion 233 is inclined relative to the buffer main body 231 and is located on the side of the expandable surface 2201 close to the first surface 2202. As a result, the gas accommodating portion 233 can be arranged close to the conductive portion 222. The space around the conductive portion 222 can be fully utilized to arrange the gas accommodating portion 233, which is beneficial to improving the compactness of the internal structure of the battery cell 20. No additional space is required to set the gas accommodating portion 233. While improving the reliability of the buffer main body 231, it is beneficial to make the battery cell 20 have a higher volume energy density.

[0099] In some embodiments of the present application, reference Figure 4 , the first surface 2202 is one and is arranged at the top of the electrode main body 221. In this technical solution, the conductive part 222 is arranged at the top of the electrode main body 221, and the gas containing part 233 is also arranged at the top of the electrode assembly 22. The battery cell 20 adopting this structure can be provided with the electrode terminal 201 at the top, which can facilitate the installation and connection of the battery cell 20 and make the battery cell 20 have higher reliability.

[0100] In some embodiments of the present application, there are at least two first surfaces 2202 , and at least one first surface 2202 is correspondingly provided with a gas accommodating portion 233 .

[0101] In this embodiment, two, three, four, etc. surfaces adjacent to the expandable surface 2201 may be the first surfaces 2202, thereby enabling the conductive portion 222 to be provided at a plurality of positions of the electrode body 221. In this embodiment, a gas accommodating portion 233 may be provided at a position where one of the first surfaces 2202 is located; or, a gas accommodating portion 233 may be provided at a position where two or three, etc. of a plurality of first surfaces 2202 are located. By providing a plurality of gas accommodating portions 233, the gas pressure in the buffer body 231 can be quickly balanced, thereby improving the reliability of the buffer body 231.

[0102] In the above technical solution, there are at least two first surfaces 2202 of the electrode main body 221, and therefore there may be at least two conductive parts 222, so that a plurality of electrode terminals 201 may be provided corresponding to the outer shell 21. That is to say, the battery cell 20 in this solution may constitute a structure in which electrode terminals 201 are provided on a plurality of surfaces. By providing a gas containing portion 233 corresponding to at least one first surface 2202, the reliability of the battery cell 20 of this structure may be improved.

[0103] In some embodiments of the present application, reference Figure 6There are two first surfaces 2202 located at opposite ends of the electrode body 221 , and the two first surfaces 2202 are each correspondingly provided with a gas containing portion 233 .

[0104] In the above technical solution, the first surfaces 2202 are arranged at the opposite ends of the electrode main body 221, so the conductive parts 222 can be arranged at the opposite ends of the electrode main body 221, and the electrode terminals 201 are also arranged at the opposite ends of the outer shell 21. That is to say, the battery cell 20 in this solution can constitute a structure in which the electrode terminals 201 are arranged at two opposite end surfaces. By correspondingly providing the gas accommodating parts 233 on the two first surfaces 2202, the reliability of the battery cell 20 of this structure can be improved.

[0105] In some embodiments of the present application, the first surface 2202 is located at least at one end of the electrode body 221 in the first direction X. In the first direction X, one end of the buffer body 231 close to the first surface 2202 extends out of the first surface 2202 or is flush with the first surface 2202 .

[0106] The “first direction X of the electrode main body 221” can refer to Figure 3 and Figure 4 In this embodiment, the first surface 2202 may be disposed in the first direction X of the electrode main body 221, wherein the first surface 2202 may be disposed at one end of the electrode main body 221 in the first direction X (refer to Figure 3 and Figure 4 ), the first surface 2202 can also be arranged at both ends of the first direction X of the electrode main body 221.

[0107] “One end of the buffer body 231 close to the first surface 2202 extends out of the first surface 2202 or is flush with the first surface 2202” can be understood as that the end of the buffer body 231 close to the first surface 2202 can exceed the first surface 2202, that is, the buffer body 231 is protruding relative to the first surface 2202, or the end of the buffer body 231 close to the first surface 2202 can also be flush with the first surface 2202.

[0108] In the above technical solution, in the first direction X, one end of the buffer main body 231 close to the first surface 2202 extends out of the first surface 2202 or is flush with the first surface 2202, so that the buffer main body 231 can completely cover the expandable surface 2201 in the first direction X, which can provide better support for the expandable surface 2201, reduce the probability of wrinkling at the edge of the electrode assembly 22 in the first direction X and causing a poor interface, which is beneficial to improving the reliability of the electrode assembly 22, and further improve the reliability of the battery cell 20.

[0109] In some embodiments of the present application, reference Figure 4In the first direction X, the size of the electrode body portion 221 is W, and the size of the buffer body portion 231 is H1, wherein W+1mm≤H1≤W+3mm.

[0110] The size H1 of the buffer body 231 may be, but is not limited to, W+1mm, W+1.2mm, W+1.4mm, W+1.5mm, W+1.6mm, W+1.8mm, W+2.0mm, W+2.2mm, W+2.4mm, W+2.5mm, W+2.6mm, W+2.8mm, W+3mm, and the like.

[0111] The size H1 of the buffer body 231 must be at least 1 mm larger than the size W of the electrode body 221, so that a certain assembly error can be allowed when the buffer 23 and the expandable surface 2201 are matched in the first direction X, which is conducive to reducing the probability that the buffer 23 cannot cover the edge position of the expandable surface 2201. 3mm can refer to the maximum height allowed by the buffer body 231 beyond the first surface 2202. Since the conductive part 222 is a component formed by stacking the extended parts of multiple pole pieces, the height of the conductive part 222 on the first surface 2202 is relatively small (generally 3.5mm). If the height of the buffer body 231 beyond the first surface 2202 is greater than 3mm, the buffer body 231 will increase additional space, that is, the buffer body 231 will occupy a larger space, which will further reduce the volume energy density of the battery cell 20.

[0112] In the above technical solution, by setting the relationship between the dimension W of the electrode main body 221 in the first direction X and the dimension H1 of the buffer main body 231 in the first direction X within the above range, the buffer main body 231 and the expandable surface 2201 can meet the assembly error while enhancing the supporting effect of the buffer main body 231 on the expandable surface 2201. It is also beneficial to reduce the space required for the buffer main body 231, so that the battery cell 20 has a higher volume energy density while having a higher reliability.

[0113] In some embodiments of the present application, reference Figure 4 The electrode body 221 is provided with a second surface 2203, and the second surface 2203 is arranged at both ends of the second direction Y of the electrode body 221, and is connected to the expandable surface 2201 and the first surface 2202. The second surface 2203 is an arc surface, wherein the second direction Y and the first direction X are arranged at an angle. In the second direction Y, the end of the buffer body 231 close to the second surface 2203 extends out of the expandable surface 2201, or the end of the buffer body 231 close to the second surface 2203 is flush with the edge where the expandable surface 2201 and the second surface 2203 are connected.

[0114] The second surface 2203 may be a surface of the electrode body 221 that is in contact with the expandable surface 2201 and the first surface 2202 .

[0115] “The second direction Y and the first direction X are arranged at an angle” may mean that the second direction Y and the first direction X are not parallel and are not in the same direction. Optionally, the angle between the second direction Y and the first direction X may be 90 degrees.

[0116] In the above technical solution, in the second direction Y, the buffer main body 231 extends the expandable surface 2201 at one end close to the second surface 2203 or is flush with the edge connected to the second surface 2203, so that the buffer main body 231 can fully cover the expandable surface 2201 at both ends of the second direction Y, which can provide better support for the expandable surface 2201, reduce the probability of a bad interface at the edge position of the electrode assembly 22 in the second direction Y, and further improve the reliability of the electrode assembly 22, thereby improving the reliability of the battery cell 20.

[0117] In some embodiments of the present application, reference Figure 4 In the second direction Y, the size of the expandable surface 2201 is L, and the size of the buffer body 231 is H2, wherein L+1mm≤H2≤L+4mm.

[0118] The size H2 of the buffer body 231 can be but is not limited to L+1mm, L+1.2mm, L+1.4mm, L+1.6mm, L+1.8mm, L+2.0mm, L+2.2mm, L+2.4mm, L+2.6mm, L+2.8mm, L+3.0mm, L+3.2mm, L+3.4mm, L+3.6mm, L+3.8mm, L+4mm, etc.

[0119] The size H2 of the buffer body 231 must be at least 1mm larger than the size L of the expandable surface 2201, thereby allowing a certain assembly error when the buffer 23 and the expandable surface 2201 are matched in the second direction Y, which is beneficial to reduce the probability that the buffer body 231 cannot cover the edge position of the expandable surface 2201. 4mm may refer to the maximum length allowed by the buffer body 231 to exceed the expandable surface 2201. Since the second surface 2203 is a curved surface, the chamfer of the second surface 2203 is relatively small (generally the chamfer radius is 5mm). If the length of the buffer body 231 exceeding the expandable surface 2201 is greater than 4mm, it will cause the buffer body 231 to exceed the second surface 2203, so that the buffer body 231 occupies a larger space, thereby reducing the volume energy density of the battery cell 20.

[0120] In the above technical solution, by setting the relationship between the dimension L of the expandable surface 2201 in the second direction Y and the dimension H2 of the buffer body 231 in the second direction Y within the above range, the buffer body 231 and the expandable surface 2201 can meet the assembly error, and the buffer body 231 can have a higher probability of fully covering the expandable surface 2201, thereby enhancing the supporting effect of the buffer body 231 on the expandable surface 2201. It is also beneficial to reduce the space required for the buffer body 231, so that the battery cell 20 has a higher reliability and a higher volume energy density.

[0121] In some embodiments of the present application, reference Figure 3 , Figure 4 and Figure 6 The electrode assembly 22 is a winding core assembly, which is flat and has a central gap 2204 formed in the middle. The electrode assembly 22 is provided with a second surface 2203. The second surface 2203 and the expandable surface 2201 are located on the peripheral side of the central gap 2204. The expandable surface 2201 is a plane, and the second surface 2203 is an arc surface and is connected to the expandable surface 2201. The orthographic projection of the central gap 2204 on the expandable surface 2201 is located within the orthographic projection of the buffer body 231 on the expandable surface 2201.

[0122] The core assembly may refer to a winding body formed by winding the pole piece and the isolation film after being stacked. After the core assembly is wound and formed, the gap at the center is the center gap 2204. Specifically, the core assembly may be flat.

[0123] In the above technical solution, the positive projection of the central gap 2204 on the expandable surface 2201 is located within the positive projection of the buffer body 231 on the expandable surface 2201, so that the buffer body 231 does not need to fully cover the expandable surface 2201, and can fully cover the area where the central gap 2204 is located on the expandable surface 2201. Since in the core assembly structure, the area where the central gap 2204 on the expandable surface 2201 is located is the area where the force is most concentrated when the pole piece expands, and it is also the area with a higher probability of expansion and deformation. Therefore, by covering the buffer body 231 within the range of this area, it can play a better supporting role, reduce the probability of wrinkling of the electrode assembly 22 and causing a bad interface, and is also conducive to reducing the size of the buffer body 231 and reducing costs. In addition, the above solution can also reduce the volume of the buffer 23, so that there is more space in the shell 21 for filling the electrolyte, which is conducive to improving the performance of the battery cell 20.

[0124] In some embodiments of the present application, reference Figure 4The electrode assembly 22 has a first direction X, a second direction Y and a third direction Z. The central gap 2204 penetrates the electrode assembly 22 along the first direction X. The second surface 2203 is located at both ends of the second direction Y of the electrode assembly 22. The expandable surface 2201 is located at both ends of the third direction ZZ of the electrode assembly 22. In the first direction X, the size of the electrode assembly 22 is W, and the size of the buffer body 231 is H1, wherein W+1mm≤H1≤W+3mm; in the second direction Y, the size of the central gap 2204 is N, and the size of the buffer body 231 is H2, wherein N+1mm≤H2≤N+3mm.

[0125] The size H1 of the buffer body 231 may be, but is not limited to, W+1mm, W+1.2mm, W+1.4mm, W+1.5mm, W+1.6mm, W+1.8mm, W+2.0mm, W+2.2mm, W+2.4mm, W+2.5mm, W+2.6mm, W+2.8mm, W+3mm, and the like.

[0126] It is understandable that the size H1 of the buffer body 231 must be at least 1 mm larger than the size W of the electrode assembly 22, thereby allowing a certain assembly error when the buffer 23 and the expandable surface 2201 are matched in the first direction X, which is conducive to reducing the probability that the buffer body 231 cannot cover the edge position of the expandable surface 2201. 3mm may refer to the maximum length allowed by the buffer body 231 to exceed the expandable surface 2201. If the length of the buffer body 231 exceeding the expandable surface 2201 is greater than 3mm, the buffer body 231 will increase additional space, that is, the buffer body 231 will occupy a larger space, which will further reduce the volume energy density of the battery cell 20.

[0127] The size H2 of the buffer body 231 can be but is not limited to N+1mm, N+1.2mm, N+1.4mm, N+1.5mm, N+1.6mm, N+1.8mm, N+2.0mm, N+2.2mm, N+2.4mm, N+2.5mm, N+2.6mm, N+2.8mm, N+3mm, etc.

[0128] It is understandable that the size H2 of the buffer body 231 must be at least 1 mm larger than the size N of the central gap 2204, thereby allowing a certain assembly error when the buffer 23 and the expandable surface 2201 are matched in the first direction X, reducing the probability that the buffer 23 cannot cover the edge of the central gap 2204. 3 mm may refer to the maximum length allowed for the buffer body 231 to exceed the edge of the central gap 2204. If the length of the buffer body 231 exceeding the edge of the central gap 2204 is greater than 3 mm, on the one hand, it will cause material waste and increase costs, and on the other hand, it will also increase the probability of the buffer body 231 exceeding the edge of the electrode assembly 22, thereby causing the buffer body 231 to occupy additional space and affect the volume energy density of the battery cell 20.

[0129] In the above technical solution, by setting the size H1 of the buffer body 231 and the size W of the electrode assembly 22, as well as the size H2 of the buffer body 231 and the size N of the central gap 2204 within the above range, the buffer body 231 can provide a better support for the expandable surface 2201 while having a certain assembly error range, which is beneficial to improving the assembly qualification rate between the buffer body 231 and the electrode assembly 22, and is also beneficial to reducing the material used in the buffer body 231 and reducing the cost, and can also reduce the probability of the buffer body 231 occupying a larger space, which is beneficial to making the battery cell 20 have higher reliability while also having a higher volume energy density.

[0130] In some embodiments of the present application, reference Figure 3 The buffer member 23 is disposed between the expandable surface 2201 and the inner side surface of the outer shell 21 .

[0131] In this technical solution, the two relative surfaces of the buffer 23 are respectively attached to the expandable surface 2201 and the inner side surface of the outer shell 21. When the expandable surface 2201 of the electrode assembly 22 expands and deforms, since the outer shell 21 has a higher strength, it can better support the expandable surface 2201 by acting on the buffer 23, which is beneficial to further reduce the probability of wrinkling of the expandable surface 2201 and the occurrence of a poor interface, thereby further improving the reliability of the battery cell 20.

[0132] In some embodiments of the present application, reference Figure 8 and Fig. 9 There are at least two electrode assemblies 22, and a buffer 23 is provided between the expandable surfaces 2201 of at least one group of two adjacent electrode assemblies 22; and / or, a buffer 23 is provided between the expandable surface 2201 of the electrode assembly 22 and the inner side surface of the shell 21.

[0133] It is understandable that two, three, four, etc. electrode assemblies 22 may be disposed in the housing 21 .

[0134] For example, reference Figure 8 There may be two electrode assemblies 22, which are sequentially arranged along the third direction Z. In this case, the surfaces of the two electrode assemblies 22 facing each other in the third direction Z are expandable surfaces 2201, and a buffer 23 is arranged between the two. Alternatively, refer to Fig. 9 There are two electrode assemblies 22, which are arranged in sequence along the third direction Z. The surfaces of the two electrode assemblies 22 located in the third direction Z and close to the shell 21 are expandable surfaces 2201, and a buffer 23 is arranged between the two electrode assemblies 22 and the inner side of the shell 21; or, referring to Fig.10 There are two electrode assemblies 22, which are arranged in sequence along the third direction Z. The surfaces of each electrode assembly 22 at both ends of the third direction Z are expandable surfaces 2201. Buffer components 23 are arranged between the two electrode assemblies 22 and between the two electrode assemblies 22 and the inner side surfaces of the outer shell 21.

[0135] In the above technical solution, in the structure in which the battery cell 20 includes at least two electrode assemblies 22, the above solution can further enhance the supporting effect of the buffer member 23 on the at least two electrode assemblies 22, thereby further reducing the probability of a bad interface of the electrode assembly 22, which is beneficial to improving the reliability of the multiple electrode assemblies 22, and further improving the reliability of the battery cell 20.

[0136] In some embodiments of the present application, reference Figure 3 and Figure 4 In addition to the expandable surface 2201, the electrode assembly 22 is also provided with multiple surfaces, and the area of ​​the expandable surface 2201 is larger than the areas of the remaining surfaces.

[0137] In the above scheme, the expandable surface 2201 may refer to the surface with the largest area in the electrode assembly 22. When the electrode assembly 22 expands and deforms, it is more likely to concentrate on the expandable surface 2201. The buffer component 23 is supported on the surface with the largest area of ​​the electrode assembly 22. The buffer component 23 has a better supporting effect on the electrode assembly 22, which is beneficial to further reduce the probability of a bad interface in the electrode assembly 22 and better improve the reliability of the battery cell 20.

[0138] The battery cell 20 provided in the first embodiment of the present application includes: a housing 21, an electrode assembly 22 and a buffer 23. The electrode assembly 22 has a tab at the top. The buffer 23 is arranged on the large surface of the electrode assembly 22, and the buffer 23 includes a buffer body 231, a sealing layer and an air bag. The sealing layer is wrapped on the buffer body 231, and part of the sealing layer extends out of the buffer body 231 to form an air bag. The air bag and the tab of the electrode assembly 22 extend in the same direction and are located at the top of the electrode assembly 22.

[0139] The structure of the battery cell 20 provided in the second embodiment of the present application is substantially the same as that of the battery cell 20 in the first embodiment, except that: the electrode assembly 22 has pole ears at opposite ends, and the sealing layer extends a buffer body 231 at both ends of the electrode assembly 22 in the direction of the pole ears, and air bags are formed, and the air bags are located at opposite ends of the pole ears of the electrode assembly 22 and close to the pole ears.

[0140] The structure of the battery cell 20 provided in the third embodiment of the present application is substantially the same as that of the battery cell 20 in the first embodiment, except that the electrode assembly 22 is a winding core structure, and the direction of the pole ear at the top of the electrode assembly 22 is the same as the winding axis direction of the winding core structure, which is recorded as the first direction X, and the width direction of the electrode assembly 22 is recorded as the second direction Y. In the first direction X, the size W of the winding core structure and the size H1 of the buffer body 231 satisfy: W+1mm≤H1≤W+3mm; in the second direction Y, the size N of the central gap 2204 of the winding core structure and the size H2 of the buffer body 231 satisfy: N+1mm≤H2≤N+3mm.

[0141] The structure of the battery cell 20 provided in the fourth embodiment of the present application is substantially the same as that of the battery cell 20 in the second embodiment, except that the electrode assembly 22 is a winding core structure, the direction of the pole ears at both ends of the electrode assembly 22 is the same as the winding axis direction of the winding core structure, and is recorded as the second direction Y, and the height direction of the electrode assembly 22 is recorded as the first direction X. In the first direction X, the size N of the central gap 2204 of the winding core structure and the size H2 of the buffer body 231 satisfy: N+1mm≤H2≤N+3mm; in the second direction Y, the size W of the winding core structure and the size H1 of the buffer body 231 satisfy: W+1mm≤H1≤W+3mm.

[0142] In a second aspect, the embodiment of the present application further provides a battery 100 , comprising the battery cell 20 described above.

[0143] In the above technical solution, since the battery cell 20 has relatively high reliability, the reliability of the battery 100 can be improved, which is beneficial to improving the performance of the battery 100 and extending the service life of the battery 100.

[0144] In a third aspect, an embodiment of the present application further provides an electrical device, including the battery cell 20 described above, or the battery 100 described above.

[0145] In the above technical solution, since the battery cell 20 and the battery 100 have high reliability, the reliability of the electric device can be improved, which is beneficial to improving the performance of the electric device and extending the service life of the electric device.

[0146] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0147] 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 variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: shell; an electrode assembly, the electrode assembly being disposed in the housing and having an expandable surface; The buffer component is arranged in the shell and is closely arranged on the expandable surface. The buffer component includes a buffer body and a sealing part. The sealing part is wrapped around the buffer body.

2. The battery cell according to claim 1, characterized in that: The buffer body is provided with a plurality of side portions, and the plurality of side portions are arranged along the circumference of the buffer body. The buffer member includes a gas accommodating portion, and the gas accommodating portion is provided on at least one of the side portions and can exchange gas with the buffer body.

3. The battery cell according to claim 2, characterized in that: The sealing portion is provided with a first extending portion extending out of the buffer body portion, and the first extending portion forms the gas accommodating portion.

4. The battery cell according to claim 2, characterized in that: The electrode assembly includes a connected electrode main body and a conductive part, the electrode main body is provided with a first surface and the expandable surface, the first surface is arranged adjacent to the expandable surface, the conductive part is arranged on the first surface, and the gas accommodating part is inclined relative to the buffer main body and is located on the side of the expandable surface close to the first surface.

5. The battery cell according to claim 4, characterized in that: The first surface is one and is arranged on the top of the electrode body.

6. The battery cell according to claim 4, characterized in that: There are at least two first surfaces, and at least one of the first surfaces is provided with the gas containing portion.

7. The battery cell according to claim 6, characterized in that: There are two first surfaces located at two opposite ends of the electrode body, and the two first surfaces are each correspondingly provided with the gas containing portion.

8. The battery cell according to claim 4, characterized in that: The first surface is located at least at one end of the electrode body in a first direction. In the first direction, one end of the buffer body close to the first surface extends out of the first surface or is flush with the first surface.

9. The battery cell according to claim 8, characterized in that: In the first direction, the size of the electrode main body is W, and the size of the buffer main body is H1, wherein W+1mm≤H1≤W+3mm.

10. The battery cell according to claim 8, characterized in that: The electrode body is provided with a second surface, which is provided at both ends of the electrode body in the second direction and is connected to the expandable surface and the first surface, and the second surface is a curved surface, wherein: The second direction is arranged at an angle to the first direction, and in the second direction, the end of the buffer body portion close to the second surface extends out of the expandable surface, or the end of the buffer body portion close to the second surface is flush with the edge where the expandable surface and the second surface meet.

11. The battery cell according to claim 10, characterized in that: In the second direction, the size of the expandable surface is L, and the size of the buffer body is H2, wherein L+1mm≤H2≤L+4mm.

12. The battery cell according to claim 1, characterized in that: The electrode assembly is a winding core assembly, which is flat and has a central gap formed in the middle. The electrode assembly is provided with a second surface, and the second surface and the expandable surface are located on the peripheral side of the central gap. The expandable surface is a plane, and the second surface is an arc surface and is connected to the expandable surface, wherein the orthographic projection of the central gap on the expandable surface is located within the orthographic projection of the buffer body on the expandable surface.

13. The battery cell according to claim 12, characterized in that: The electrode assembly has a first direction, a second direction and a third direction, the central gap penetrates the electrode assembly along the first direction, the second surface is located at two ends of the electrode assembly in the second direction, and the expandable surface is located at two ends of the electrode assembly in the third direction; In the first direction, the size of the electrode assembly is W, and the size of the buffer body is H1, wherein W+1mm≤H1≤W+3mm; in the second direction, the size of the central gap is N, and the size of the buffer body is H2, wherein N+1mm≤H2≤N+3mm.

14. The battery cell according to claim 1, characterized in that: The buffer is disposed between the expandable surface and the inner side surface of the outer shell.

15. The battery cell according to claim 1, characterized in that: There are at least two electrode assemblies, and the buffer is provided between the expandable surfaces of at least one group of two adjacent electrode assemblies; and / or the buffer is provided between the expandable surface of the electrode assembly and the inner side surface of the shell.

16. The battery cell according to claim 1, characterized in that: The electrode assembly is provided with a plurality of surfaces in addition to the expandable surface, and the area of ​​the expandable surface is larger than the areas of the remaining surfaces.

17. A battery, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 16.

18. An electrical device, characterized in that: Comprising the battery cell according to any one of claims 1 to 16, or the battery according to claim 17.

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