Battery monomer, battery and electric device

Abstract

The utility model is suitable for the technical field of power batteries, and provides a battery monomer, a battery and a power utilization device. A battery cell includes: an electrode assembly including a flat portion and a bent portion connected to the flat portion; the shell is used for containing the electrode assembly, the shell comprises a first wall and a second wall connected to the first wall, the first wall and the bent part are oppositely arranged in a spaced mode, the second wall and the flat part are oppositely arranged in a spaced mode, the first wall comprises an arc-shaped face opposite to the bent part, and the arc-shaped face is the arc-shaped face with the circle center located in the shell; according to the battery monomer provided by the embodiment of the invention, the first wall of the shell is provided with the arc-shaped surface opposite to the bent part, and the arc-shaped surface is the arc-shaped surface, so that the contact area between the bent part and the arc-shaped surface can be increased under the condition that the electrode assembly expands, and the condition of stress concentration can be relieved.

Description

Technical Field

[0001] This application relates to the technical field of power batteries for electric vehicles, and particularly to a battery cell, a battery and an electric device. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] During the use of the battery, the active layer of the electrode plate is prone to swelling. During the swelling and deformation of the electrode plate, the amount of deformation at each position of the electrode plate is not the same, resulting in stress concentration on the electrode plate. As the electrode assembly gradually ages, the electrode plate is prone to cracking in the stress concentration area, which has a negative impact on the safety performance and service life of the battery. Summary of the Utility Model

[0004] In view of the above problems, this application provides a battery cell, a battery and an electric device, which can alleviate the problem of stress concentration caused by the swelling of the electrode plate.

[0005] In a first aspect, an embodiment of this application provides a battery cell, including: an electrode assembly, the electrode assembly includes a flat portion and a bent portion connected to the flat portion; a housing for accommodating the electrode assembly, the housing includes a first wall and a second wall connected to the first wall, the first wall is opposite to and spaced from the bent portion, the second wall is opposite to and spaced from the flat portion, the first wall includes an arc surface opposite to the bent portion, and the arc surface is adapted to the side surface of the bent portion.

[0006] In the technical solution of this embodiment, the first wall of the housing has an arc surface opposite to the bent portion. In the case of the swelling of the electrode assembly, this setting can increase the contact area between the bent portion and the arc surface, thereby alleviating the stress concentration.

[0007] In some embodiments, the number of electrode assemblies is at least two, and the plurality of electrode assemblies are arranged in the width direction of the battery cell, and two adjacent flat portions are arranged opposite to each other.

[0008] In the technical solution of this embodiment, the battery cell includes at least two electrode assemblies, and the flat portions of the electrode assemblies are in contact with each other. At this time, the first wall can limit the amount of deformation of the bent portion of each battery cell, and enable the swelling force of each battery cell to be released in the direction of the second wall, thereby alleviating the problem that the connection part between the bent portion and the flat portion is prone to fracture, and also alleviating the stress concentration of the bent portion.

[0009] In some embodiments, the first wall includes at least two arc-shaped surfaces arranged along the width direction of the battery cell, and each arc-shaped surface is opposite to an adjacent bent portion respectively.

[0010] In the technical solution of this embodiment, the first wall is made to include at least two arc-shaped surfaces, and each arc-shaped surface is opposite to an adjacent bent portion respectively, so that each arc-shaped surface can limit the expansion of each bent portion respectively, thereby better limiting the expansion of the bent portion and reducing the force exerted on the adjacent electrode assembly by the expansion of the bent portion.

[0011] In some embodiments, a limiting member is provided between the bent portions of two adjacent electrode assemblies.

[0012] In the technical solution of this embodiment, a limiting member is provided between the first wall and the adjacent bent portion to fill the gaps between the first wall and the adjacent bent portion and between two adjacent bent portions through the limiting member, so that the limiting member can limit the expansion of the bent portion and reduce the force exerted on the adjacent electrode assembly by the expansion of the bent portion.

[0013] In some embodiments, a side of the limiting member facing the bent portion is spaced from the bent portion.

[0014] In the technical solution of this embodiment, a gap is provided between the limiting member and the adjacent bent portion to provide an expansion space for the bent portion, so as to facilitate the bent portion to release part of the expansion force and relieve the problems of large internal stress and stress concentration in the bent portion.

[0015] In some embodiments, the distance between a side of the limiting member facing the bent portion and the corresponding bent portion is smaller than the distance between the second wall and the flat portion.

[0016] In the technical solution of this embodiment, a gap is provided between the limiting member and the bent portion to provide space for the expansion of the bent portion; the distance between the limiting member and the bent portion is made smaller than the distance between the second wall and the flat portion to limit the expansion deformation amount of the bent portion and provide a larger space for the expansion of the flat portion, reducing the difference between the expansion deformation amount of the bent portion and the expansion deformation amount of the flat portion, so that the expansion force of the electrode assembly can be released to the flat portion, thereby reducing the expansion force on the bent portion.

[0017] In some embodiments, the limiting member abuts against the bent portion.

[0018] In the technical solution of this embodiment, the limiting member is made to abut against the bent portion so that the limiting member can further limit the expansion deformation amount of the electrode assembly; at the same time, the limiting member can also play a role in assisting in fixing the electrode assembly.

[0019] In some embodiments, the limiting member is an elastic member, and the maximum deformation amount of the limiting member is smaller than the distance between the second wall and the flat portion.

[0020] In the technical solution of this embodiment, the maximum deformation of the limiting member is made smaller than the distance between the second wall and the flat portion. In the case of the expansion of the electrode assembly, this setting can limit the expansion deformation of the bending portion and provide a larger space for the expansion of the flat portion, so as to reduce the difference between the expansion deformation of the bending portion and the expansion deformation of the flat portion, and enable the expansion force of the electrode assembly to be released to the flat portion, thereby reducing the expansion force on the bending portion, alleviating the problem that the connection part between the bending portion and the flat portion is prone to fracture, and also alleviating the stress concentration of the bending portion.

[0021] In some embodiments, there are two first walls and two second walls. The two first walls and the two second walls are connected end to end in sequence and enclose a first accommodation cavity, and the first accommodation cavity is used to accommodate at least part of the electrode assembly.

[0022] The technical solution of this embodiment provides some structures of the housing, so that the housing includes a first wall and a second wall connected end to end. At this time, the first wall can be used as the circumferential side wall structure of the housing and form a special-shaped housing.

[0023] In some embodiments, the first accommodation cavity is a space with at least one side open; the housing further includes a sub-housing. In the height direction of the battery cell, the sub-housing is arranged on at least one side of the first wall and on the opening side of the first accommodation cavity; a second accommodation cavity is arranged in the sub-housing, and the second accommodation cavity is communicated with the first accommodation cavity.

[0024] In the technical solution of this embodiment, a sub-housing is arranged on at least one side of the first wall, and the second accommodation cavity of the sub-housing can be communicated with the first accommodation cavity to increase the space for accommodating the electrolyte and improve the performance of the battery; at the same time, in the case where the first wall and the second wall form a special-shaped structure, the sub-housing can be adapted to the top cover or other structures to facilitate the processing and assembly of the housing.

[0025] In some embodiments, at least part of the electrode assembly is accommodated in the second accommodation cavity.

[0026] In the technical solution of this embodiment, part of the electrode assembly can enter the second accommodation cavity, so as to reduce the overall volume of the housing and increase the energy density of the battery cell.

[0027] In some embodiments, in the arrangement direction of the sub-housing and the first wall, the size of the first wall is smaller than the size of the electrode assembly, and the difference between the size of the electrode assembly and the size of the first wall is less than or equal to 2 mm.

[0028] In the technical solution of this embodiment, the size of the first wall in the arrangement direction of the sub-shell and the first wall is made smaller than the size of the electrode assembly, so that part of the electrode assembly can enter the second accommodating cavity, thereby reducing the overall volume of the shell and increasing the energy density of the battery cell; the technical solution of this embodiment also limits the relationship between the size of the first wall in the arrangement direction of the sub-shell and the first wall and the size of the electrode assembly. When the electrode assembly expands, this arrangement can reduce the stress concentration at the edge of the electrode assembly in the height direction of the first wall.

[0029] In some embodiments, the battery cell further includes an end plate, and the end plate is disposed on a side of the subhousing away from the first wall.

[0030] In the technical solution of this embodiment, the end plate covers the side of the sub-shell away from the first wall, so as to cooperate with the shell and the sub-shell to form a closed accommodating space.

[0031] In some embodiments, the shell also includes a third wall connected to the second wall, and the third wall is located on the side of the first wall away from the first accommodating cavity; in the length direction of the battery cell, the third wall and the first wall are spaced apart, and a third accommodating cavity is formed between the first wall, the two second walls and the third wall, and the third accommodating cavity is connected to the first accommodating cavity.

[0032] In the technical solution of this embodiment, the shell includes a third wall, so that the third wall can cooperate with the second wall to form the internal space of the shell. At this time, the first wall is located inside the shell. This setting can make the shape of the shell a common shape to meet the needs of other structures and reduce the negative impact on battery processing and assembly; at the same time, the third wall can also cooperate with the first wall and the second wall to form a third accommodating cavity, and the third accommodating cavity is connected to the first accommodating cavity to increase the accommodating space for the electrolyte and improve the performance of the battery cell.

[0033] In some embodiments, a first through hole is provided on the first wall to connect the first accommodating cavity and the third accommodating cavity.

[0034] The technical solution of this embodiment provides some ways for the third accommodation chamber to communicate with the first accommodation chamber, so that the battery cell can have a larger electrolyte accommodation space.

[0035] In some embodiments, in the arrangement direction of the sub-housing and the first wall, the size of the third wall is equal to the size of the second wall, and the size of the first wall is smaller than the size of the second wall.

[0036] The technical solution of this embodiment provides other ways of connecting the third accommodation cavity and the first accommodation cavity, so that the battery cell can have a larger electrolyte accommodation space.

[0037] In some embodiments, in the arrangement direction of the sub-housing and the first wall, the difference between the size of the first wall and the size of the second wall is less than or equal to 2 mm

[0038] The technical solution of this embodiment provides some more ways for the third accommodation cavity to communicate with the first accommodation cavity, so that the battery cell can not only have a large electrolyte accommodation space, but also reduce the stress concentration at the edge of the first wall of the electrode assembly.

[0039] In some embodiments, the battery cell further includes a support plate, which is arranged in the first accommodation cavity and abuts against the adjacent first wall and the second wall.

[0040] In the technical solution of this embodiment, the circumferential side of the support plate abuts against the first wall and the second wall, so that the shape of the support plate can adapt to the shapes of the first wall and the second wall, which is convenient for the installation of the support plate and improves the compatibility of the support plate.

[0041] In some embodiments, the support plate is provided with a second through hole.

[0042] In the technical solution of this embodiment, a second through hole is provided on the support plate, so that the electrolyte can flow through the support plate and better infiltrate the electrode assembly.

[0043] In some embodiments, the battery cell further includes an insulating film that wraps the electrode assembly. The insulating film includes an arc section, and the arc section is disposed opposite to the bent portion.

[0044] In the technical solution of this embodiment, the shape of the insulating film can adapt to the shapes of the first wall and the second wall, which improves the compatibility of the insulating film.

[0045] In some embodiments, the difference between the maximum width of the housing and the maximum width of the electrode assembly is greater than the difference between the maximum length of the housing and the maximum length of the electrode assembly.

[0046] In the technical solution of this embodiment, the difference between the maximum width of the housing and the maximum width of the electrode assembly is greater than the difference between the maximum length of the housing and the maximum length of the electrode assembly. In the case of the expansion of the electrode assembly, this setting can limit the expansion deformation amount of the bent portion and provide a larger space for the expansion of the flat portion, so as to reduce the difference between the expansion deformation amount of the bent portion and the expansion deformation amount of the flat portion, and can release the expansion force of the electrode assembly to the flat portion, thereby reducing the expansion force on the bent portion and alleviating the problem that the connection part between the bent portion and the flat portion is prone to fracture, and can also alleviate the stress concentration of the bent portion.

[0047] In some embodiments, the distance between the second wall and the flat portion is greater than the distance between the arc surface and the bent portion.

[0048] In the technical solution of this embodiment, the dimensional relationship between the bending part, the flat part and the adjacent wall surface is further restricted to alleviate the problems of stress concentration and local easy fracture of the electrode assembly; at the same time, this setting can also enable the electrode assembly to be located in the middle of the housing, thereby reducing the problem of local stress concentration caused by the position offset of the electrode assembly.

[0049] Secondly, some embodiments of the present application also provide a battery, including the battery cells provided by some embodiments of the first aspect.

[0050] Thirdly, some embodiments of the present application also provide an electrical device, including the battery provided by some embodiments of the second aspect.

[0051] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically describes the specific implementation manners of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0053] Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application;

[0054] Figure 2 is an exploded structural diagram of a battery provided by some embodiments of the present application;

[0055] Figure 3 is an exploded structural diagram of a battery cell provided by some embodiments of the present application;

[0056] Figure 4 is a top view of the internal structure of a battery cell provided by some embodiments of the present application Figure 1 ;

[0057] Figure 5 is a top view of the internal structure of a battery cell provided by some embodiments of the present application Figure 2 ;

[0058] Figure 6 is Figure 4 a partial enlarged view of part A in

[0059] Figure 7 is a top view of the internal structure of a battery cell provided by some other embodiments of the present application;

[0060] Figure 8 is Figure 7 The partial enlarged schematic view at position B in

[0061] Figure 9 The top view schematic of the internal structure of the battery cell provided by some other embodiments of the present application;

[0062] Figure 10 is Figure 9 The partial enlarged schematic view at position C in

[0063] Figure 11 The three - dimensional schematic of the housing provided by some embodiments of the present application Figure 1 ;

[0064] Figure 12 The three - dimensional schematic of the housing provided by some embodiments of the present application Figure 2 ;

[0065] Figure 13 The three - dimensional schematic view of the housing provided by some other embodiments of the present application;

[0066] Figure 14 The top view schematic of the housing provided by some other embodiments of the present application;

[0067] Figure 15 is Figure 14 The sectional three - dimensional schematic view at D - D in

[0068] Figure 16 The structural schematic view of the pallet in the battery cell provided by some embodiments of the present application;

[0069] Figure 17 The schematic view of the size relationship between the pallet and the insulating film in the battery cell provided by some embodiments of the present application.

[0070] The meanings of the marks in the figure are:

[0071] 1000, vehicle;

[0072] 100, battery;

[0073] 10, box body; 11, upper box body; 12, lower box body;

[0074] 20. Battery cell; 21. Electrode assembly; 211. Flat part; 212. Bending part; 22. Housing; 221. First accommodation cavity; 222. Second accommodation cavity; 223. First wall; 2231. Arc surface; 2232. First through hole; 224. Second wall; 225. Third wall; 226. Sub-housing; 2261. Third accommodation cavity; 227. End plate; 23. End cover; 24. Support plate; 241. Second through hole; 25. Limiting member; 26. Insulating film; 261. Arc segment; 262. Plane segment; 27. Electrode terminal;

[0075] 200. Motor;

[0076] 300. Controller. Detailed implementation manners

[0077] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0079] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two unless otherwise specifically defined.

[0080] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0081] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0082] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0083] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present application.

[0084] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0085] Currently, from the perspective of the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind, and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles, as well as in multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of power batteries, the market demand is also continuously increasing.

[0086] During the use of the electrode assembly, the active layer on the electrode tab is prone to swelling. Affected by the winding structure characteristics of the electrode assembly, when the flat part of the electrode assembly swells to abut against the housing, further swelling deformation will be restricted by the housing. At this time, there is still space between the bent part of the electrode assembly and the housing. That is, when the flat part cannot continue to swell and deform, the bent part can still further swell and deform. This will cause the swelling deformation amounts of the flat part and the bent part of the electrode assembly to be inconsistent, and it is easy to cause stress concentration at the intersection of the bent part and the flat part. This stress will gradually accumulate on the outermost electrode tab of the electrode assembly, and a relatively obvious boundary (i.e., the stress concentration site) will be formed between the bent part and the flat part. As the electrode assembly gradually swells and deforms, the gap in the swelling deformation amounts between the bent part and the flat part will become larger and larger, the stress concentration phenomenon will become more and more serious, and the risk of electrode tab fracture will become higher and higher.

[0087] Moreover, since the current housings are mostly square, and the bent parts of the electrode assemblies are mostly arc-shaped, when the electrode assembly swells and the bent part abuts against the housing, the contact area between the bent part and the housing is small, and even a line contact situation may occur, resulting in stress concentration at the contact position between the bent part and the housing, and it is easy to cause electrode tab fracture.

[0088] In order to alleviate the problem of stress concentration caused by the swelling of the electrode tab, the present application provides a battery cell, including a first wall and a second wall, making the first wall face the bent part, and making the first wall include an arc-shaped surface facing the bent part.

[0089] In such a battery cell, the arc-shaped surface can increase the contact area between the bent part and the arc-shaped surface when the electrode assembly swells, so as to alleviate the stress concentration situation, thereby reducing the risk of electrode tab fracture at the contact position between the bent part and the arc-shaped surface.

[0090] The battery cell disclosed in the embodiments of the present application can be used in an electrical device using a battery as a power source or various energy storage systems using a battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, etc.

[0091] For the convenience of description in the following embodiments, a vehicle 1000, which is an electrical device in an embodiment of the present application, is taken as an example for description.

[0092] Refer to Figure 1 , Figure 1Schematic diagram of the structure of vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 100 is disposed inside the vehicle 1000. The battery 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000. For example, the battery 100 can serve as the operating power source of the vehicle 1000. The vehicle 1000 can also include a controller 300 and a motor 200. The controller 300 is used to control the battery 100 to supply power to the motor 200. For example, it is used for the working power requirements during the start-up, navigation, and driving of the vehicle 1000.

[0093] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0094] Reference Figure 2 , Figure 2 Explosion diagram of the battery 100 provided by some embodiments of the present application. The battery 100 includes a box body 10 and battery cells 20. The battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include an upper box body 11 and a lower box body 12. The upper box body 11 and the lower box body 12 cover each other, and the upper box body 11 and the lower box body 12 jointly define an accommodation space for accommodating the battery cells 20. The lower box body 12 can be a hollow structure with one end open, and the upper box body 11 can be a plate-like structure. The upper box body 11 covers the open side of the lower box body 12 so that the upper box body 11 and the lower box body 12 jointly define an accommodation space; the upper box body 11 and the lower box body 12 can also both be hollow structures with one side open, and the open side of the upper box body 11 covers the open side of the lower box body 12. Of course, the box body 10 formed by the upper box body 11 and the lower box body 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery 100, there can be multiple battery cells 20. The multiple battery cells 20 can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a series-parallel combination together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10; of course, the battery 100 can also be in the form of multiple battery cells 20 first connected in series, in parallel, or in a series-parallel combination to form battery 100 modules, and then the multiple battery 100 modules are connected in series, in parallel, or in a series-parallel combination to form a whole and are accommodated in the box body 10. The battery 100 can also include other structures. For example, the battery 100 can also include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0096] Among them, each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc.

[0097] In a first aspect, referring to Figures 3 to 6 , some embodiments of the present application provide a battery cell 20, including an electrode assembly 21 and a housing 22. Among them, the electrode assembly 21 includes a flat portion 211 and a bent portion 212 connected to the flat portion 211; the housing 22 is used to accommodate the electrode assembly 21, the housing 22 includes a first wall 223 and a second wall 224 connected to the first wall 223, the first wall 223 is opposite to and spaced from the bent portion 212, the second wall 224 is opposite to and spaced from the flat portion 211, the first wall 223 includes an arc surface 2231 opposite to the bent portion 212, and the arc surface 2231 is an arc surface with the center of the circle located inside the housing 22.

[0098] In the figure, the direction where the X-axis is located is the length direction of the battery cell 20, the direction where the Y-axis is located is the width direction of the battery cell 20, and the direction where the Z-axis is located is the height direction of the battery cell 20.

[0099] The electrode assembly 21 is a component in the battery cell 20 where an electrochemical reaction occurs. One or more electrode assemblies 21 can be included in the housing 22. The electrode assembly 21 is mainly formed by winding a positive electrode sheet and a negative electrode sheet, and usually a separator is provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active substances constitute the main body of the electrode assembly 21, and the parts of the positive electrode sheet and the negative electrode sheet without active substances respectively constitute the electrode tabs. The positive electrode tab and the negative electrode tab can be located at one end of the main body together or at both ends of the main body respectively. During the charging and discharging process of the battery 100, the positive electrode active substance and the negative electrode active substance react with the electrolyte, and the electrode tabs are connected to the electrode terminals 27 to form a current loop.

[0100] The flat portion 211 refers to the flat part in the electrode assembly 21, the bent portion 212 refers to the bent part in the electrode assembly 21, the bent portion 212 is located on opposite sides of the electrode assembly 21, and the positive electrode sheet, the negative electrode sheet and the separator are bent to form the bent portion 212 during the winding process; the area of the flat portion 211 can be larger than the area of the bent portion 212.

[0101] Exemplarily, the flat portion 211 can be parallel to the plane where the length direction X and the height direction Z of the battery cell 20 are located, and the bent portion 212 can be located on opposite sides of the flat portion 211 along the length direction X of the battery cell 20.

[0102] The housing 22 refers to a structure or a combination of structures for forming the internal environment of the battery cell 20; the housing 22 is used to provide an accommodation space and a fixing base for the electrode assembly 21; the housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc., and the shape of the housing 22 can also be determined according to the specific shape and size of the electrode assembly 21; the material of the housing 22 can be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0103] The first wall 223 refers to a part of the structure of the housing 22. The first wall 223 can be a structure of the housing 22 exposed to the external environment of the battery cell 20, or can also be a structure located inside the battery cell 20; the shape of the first wall 223 can be rectangular, circular or other shapes, and the shape of the first wall 223 can also be set according to the shape of the housing 22; the material of the first wall 223 can include metal, plastic or other materials, and the material of the first wall 223 can also be set according to the material of the housing 22.

[0104] The first wall 223 faces the bent portion 212, that is, the first wall 223 is used to protect the bent portion 212 and limit the expansion deformation amount of the bent portion 212; the first wall 223 is spaced from the bent portion 212. When the battery cell 20 is in the natural state of not being used, there is a gap between the first wall 223 and the bent portion 212, and this gap is used to provide an expansion deformation space for the bent portion 212 so that the bent portion 212 can release part of the expansion force when the battery cell 20 expands.

[0105] Exemplarily, when the bent portion 212 is located on both sides of the electrode assembly 21 along the length direction X of the battery cell 20, the first wall 223 is also located on both sides of the housing 22 along the length direction X of the battery cell 20.

[0106] The arc surface 2231 refers to the surface of the first wall 223 facing the bent portion 212. The arc surface 2231 is adapted to the side surface of the bent portion 212, that is, the shape of the arc surface 2231 is the same as or substantially the same as the bending direction of the side surface of the bent portion 212, and the radian of the arc surface 2231 and the bent portion 212 can be the same or different; when the battery cell 20 expands and the bent portion 212 abuts against the arc surface 2231, compared with the case where the surface of the first wall 223 facing the bent portion 212 is a plane, this setting can increase the contact area between the bent portion 212 and the arc surface 2231, so as to increase the force-bearing area of the reaction force of the first wall 223 acting on the bent portion 212, thereby being able to relieve the stress concentration, reduce the force locally received by the bent portion 212, and reduce the situation where the electrode assembly 21 breaks at the contact position between the bent portion 212 and the first wall 223.

[0107] The second wall 224 refers to a partial structure of the housing 22. The second wall 224 can be a structure of the housing 22 exposed to the external environment of the battery cell 20, or can also be a structure located inside the battery cell 20; the shape of the second wall 224 can also be rectangular, circular or other shapes, and the shape of the second wall 224 can also be set according to the shape of the housing 22; the material of the second wall 224 can include metal, plastic or other materials, and the material of the second wall 224 can also be set according to the material of the housing 22.

[0108] The second wall 224 faces the flat portion 211, that is, the second wall 224 is used to protect the flat portion 211 and limit the expansion deformation amount of the flat portion 211; the second wall 224 is arranged at an interval from the flat portion 211. When the battery cell 20 is in an unused natural state, there is a gap between the second wall 224 and the flat portion 211, and this gap is used to provide an expansion deformation space for the flat portion 211, so that the flat portion 211 can release part of the expansion force when the battery cell 20 expands.

[0109] Exemplarily, when the flat portion 211 is located on both sides of the electrode assembly 21 along the width direction Y of the battery cell 20, the first wall 223 is also located on both sides of the housing 22 along the width direction Y of the battery cell 20.

[0110] The second wall 224 is connected to the first wall 223 or may not be connected to the first wall 223; when the second wall 224 is connected to the first wall 223, the second wall 224 can be directly connected to the first wall 223 or can be indirectly connected to the first wall 223 through an intermediate structure; when the second wall 224 is connected to the first wall 223, the second wall 224 can be connected to the first wall 223 by welding, gluing or other means, or the second wall 224 and the first wall 223 can be integrally formed.

[0111] In this embodiment, the arc-shaped surface 2231 of the arc can increase the contact area between the bending portion 212 and the arc-shaped surface 2231 when the electrode assembly 21 expands, so as to relieve the stress concentration, thereby reducing the risk of the pole piece breaking at the contact position between the bending portion 212 and the arc-shaped surface 2231.

[0112] Reference Figures 7 to 10 , in some embodiments, the number of the electrode assemblies 21 is at least two, and the plurality of electrode assemblies 21 are arranged along the width direction of the battery cell 20, and two adjacent flat portions 211 are arranged oppositely.

[0113] The battery cell 20 includes at least two electrode assemblies 21, that is, at least two electrode assemblies 21 are accommodated in the housing 22, and the number of the electrode assemblies 21 can be two, or can also be three or more.

[0114] A plurality of electrode assemblies 21 are arranged along the width direction Y of the battery cell 20. At this time, the adjacent flat portions 211 of two adjacent battery cells 20 face each other, and the adjacent flat portions 211 of two adjacent battery cells 20 can be in contact with each other, so that the adjacent two electrode assemblies 21 are in surface contact, thereby enabling a large contact area between the adjacent two electrode assemblies 21.

[0115] In the case where each electrode assembly 21 expands, this setting enables the adjacent flat portions 211 of two adjacent electrode assemblies 21 to come into contact with each other and expand, thereby being able to reduce the problem of stress concentration at the contact part of the adjacent electrode assemblies 21.

[0116] In this embodiment, the battery cell 20 includes at least two electrode assemblies 21, and the flat portions 211 of each electrode assembly 21 abut against each other. At this time, the first wall 223 can limit the deformation amount of the bending portion 212 of each battery cell 20, and enable the expansion force of each battery cell 20 to be released in the direction of the second wall 224, thereby being able to alleviate the problem that the connection part between the bending portion 212 and the flat portion 211 is prone to fracture, and being able to alleviate the stress concentration of the bending portion 212.

[0117] Reference Figure 7 、 Figure 8 Referring to, in an embodiment where the battery cell 20 includes at least two electrode assemblies 21, the first wall 223 includes at least two arc-shaped surfaces 2231 arranged along the width direction of the battery cell 20, and each arc-shaped surface 2231 faces the adjacent bending portion 212 respectively.

[0118] The first wall 223 includes at least two arc-shaped surfaces 2231, that is, the number of arc-shaped surfaces 2231 can be two, or three or more; each arc-shaped surface 2231 is arranged along the width direction Y of the battery cell 20, and each arc-shaped surface 2231 can be connected in sequence to form a special-shaped surface on the side of the first wall 223 facing the electrode assembly 21; each arc-shaped surface 2231 faces the adjacent bending portion 212 respectively, so that the expansion deformation amount of each bending portion 212 can be limited by the arc-shaped surface 2231.

[0119] For example, the number of arc-shaped surfaces 2231 on one first wall 223 can be the same as the number of electrode assemblies 21, so that each arc-shaped surface 2231 can face the bending portion 212 of each electrode assembly 21 respectively, thereby enabling each arc-shaped surface 2231 to be used to limit the expansion deformation amount of the adjacent bending portion 212.

[0120] In this embodiment, the first wall 223 includes at least two arc-shaped surfaces 2231, and each arc-shaped surface 2231 is respectively opposite to the adjacent bent portion 212, so that each arc-shaped surface 2231 can respectively limit the expansion of each bent portion 212, thereby better limiting the expansion of the bent portion 212 and reducing the force exerted on the adjacent electrode assembly 21 by the expansion of the bent portion 212.

[0121] Reference Figure 9 , Figure 10 , in some embodiments where the battery cell 20 includes at least two electrode assemblies 21, a limiting member 25 is provided between the bent portions 212 of two adjacent electrode assemblies 21 to limit the deformation of the portions of the bent portions 212 opposite to the limiting member 25.

[0122] The limiting member 25 refers to a structure in the battery cell 20 for limiting the expansion deformation amount of the bent portion 212. The limiting member 25 can also include a frame structure, and can also include a plate-like structure, a block-like structure or other structures; the limiting member 25 can be a rigid structural member. For example, the material of the limiting member 25 can include metal, alloy or other materials, and the limiting member 25 can also be an elastic structural member. For example, the material of the limiting member 25 can include rubber, elastic fiber or other materials.

[0123] When the battery cell 20 includes at least two electrode assemblies 21, an irregularly shaped gap will be formed between the bent portions 212 of two adjacent electrode assemblies 21; when the battery cell 20 expands, the side of the bent portion 212 facing the adjacent other bent portion 212 is not easily abutted against the arc-shaped surface 2231. At this time, the contact area between the bent portion 212 and the arc-shaped surface 2231 is reduced.

[0124] Accordingly, a limiting member 25 is provided between two adjacent bent portions 212 to limit the deformation amount of the portions of the bent portions 212 opposite to the limiting member 25 through the limiting member 25; the limiting member 25 can abut against the adjacent bent portion 212 or can be spaced from the adjacent bent portion 212; the side of the limiting member 25 facing the bent portion 212 can be an arc-shaped surface to increase the contact area between the bent portion 212 and the limiting member 25.

[0125] The side of the limiting member 25 facing the first wall 223 can abut against the arc-shaped surface 2231, and the side of the limiting member 25 facing the first wall 223 can also be spaced from the arc-shaped surface 2231; the limiting member 25 can be connected to the first wall 223 or can be connected to other structural members of the housing 22; the limiting member 25 can be fixedly connected to the first wall 223 by welding, bonding or other means, or can be detachably connected to the first wall 223 by screwing, clamping or other means.

[0126] In this embodiment, a limiting member 25 is provided between the first wall 223 and the adjacent bent portion 212, so as to fill the gaps between the first wall 223 and the adjacent bent portion 212 and between two adjacent bent portions 212 through the limiting member 25, so that the limiting member 25 can limit the expansion of the bent portion 212, reduce the difference between the expansion deformation amount of the bent portion 212 and the expansion deformation amount of the flat portion 211, and reduce the risk of stress concentration and fracture of the electrode assembly 21; at the same time, this setting can also reduce the force exerted on the adjacent electrode assembly 21 by the expansion of the bent portion 212.

[0127] Reference Figure 9 、 Figure 10 In some embodiments where the limiting member 25 is provided in the housing 22, the side of the limiting member 25 facing the bent portion 212 is spaced apart from the bent portion 212.

[0128] A gap is provided between the limiting member 25 and the adjacent bent portion 212 to provide an expansion space for the bent portion 212, so that the bent portion 212 can release part of the expansion force and relieve the problems of large internal stress and stress concentration in the bent portion 212.

[0129] It can be understood that since the difference between the width of the housing 22 and the width of the electrode assembly 21 is greater than the difference between the length of the housing 22 and the length of the electrode assembly 21, the spaced arrangement of the limiting member 25 and the bent portion 212 is not likely to cause the expansion deformation amount of the bent portion 212 to be too large, so that the limiting member 25 can cooperate with the first arc surface 2231 to limit the expansion deformation amount of the bent portion 212, thereby reducing the difference between the expansion deformation amount of the bent portion 212 and the expansion deformation amount of the flat portion 211 and reducing the risk of stress concentration and fracture of the electrode assembly 21.

[0130] Reference Figure 9 、 Figure 10 In some embodiments where the limiting member 25 is spaced apart from the bent portion 212, the distance between the side of the limiting member 25 facing the bent portion 212 and the corresponding bent portion 212 is smaller than the distance between the second wall 224 and the flat portion 211.

[0131] The distance between the side of the limiting member 25 facing the bent portion 212 and the corresponding bent portion 212 refers to the distance between the surface of the limiting member 25 facing the bent portion 212 and the corresponding bent portion 212 when the battery cell 20 is in the natural state of not being used, that is, the dimension shown as L3 in the figure.

[0132] The distance between the second wall 224 and the flat portion 211 refers to the distance between the surface of the second wall 224 facing the electrode assembly 21 and the flat portion 211 when the battery cell 20 is in the natural state of not being used, that is, the dimension shown as H3 in the figure.

[0133] The distance between the side of the limiting member 25 facing the bent portion 212 and the corresponding bent portion 212 is smaller than the distance between the second wall 224 and the flat portion 211, that is, L3 is smaller than H3; this setting enables the flat portion 211 to have a larger expansion deformation space, while the expansion deformation space of the bent portion 212 is relatively small; accordingly, after the bent portion 212 expands, it can first abut against the limiting member 25, and it is not easy for the bent portion 212 to further expand after abutting against the limiting member 25. At this time, the expansion force of the battery cell 20 will be transferred to the flat portion 211 and cause the flat portion 211 to further expand. Because the flat portion 211 is relatively flat, the contact area between the flat portion 211 and the second wall 224 during expansion is large, and stress concentration is not likely to occur during the expansion of the flat portion 211, thus achieving the effect of alleviating the fracture of the electrode assembly 21.

[0134] In this embodiment, a gap is provided between the limiting member 25 and the bent portion 212 to provide space for the expansion of the bent portion 212; the distance between the limiting member 25 and the bent portion 212 is smaller than the distance between the second wall 224 and the flat portion 211 to limit the expansion deformation amount of the bent portion 212 and be able to provide a larger space for the expansion of the flat portion 211, reducing the difference between the expansion deformation amount of the bent portion 212 and the expansion deformation amount of the flat portion 211, enabling the expansion force of the electrode assembly 21 to be released to the flat portion 211, and thus being able to reduce the expansion force on the bent portion 212.

[0135] Reference Figure 9 , in some embodiments where the limiting member 25 is provided in the housing 22, the limiting member 25 abuts against the bent portion 212.

[0136] The limiting member 25 abutting against the bent portion 212 can limit the expansion deformation amount of the bent portion 212. When the battery cell 20 expands, the expansion deformation of the bent portion 212 will abut against the limiting member 25. According to the material of the limiting member 25, the limiting member 25 can inhibit the further expansion of the bent portion 212 or provide resistance to the expansion of the bent portion 212, thereby reducing the expansion deformation amount of the bent portion 212 and reducing the difference between the expansion deformation amount of the bent portion 212 and the expansion deformation amount of the flat portion 211, and thus reducing the stress concentration at the bent portion 212 and the connection part between the bent portion 212 and the flat portion 211.

[0137] The limiting member 25 can be a rigid structure. For example, the material of the limiting member 25 includes metal, alloy or other materials; the limiting member 25 can also be an elastic structure. For example, the material of the limiting member 25 includes rubber, elastic fiber or other materials.

[0138] When the limiting member 25 abuts against the bent portion 212, the limiting member 25 can merely touch the bent portion 212, and at this time, there is no or substantially no interaction force between the limiting member 25 and the bent portion 212; the limiting member 25 can also abut against the bent portion 212 and apply a force pointing towards the inside of the housing 22 to the bent portion 212. Since the bent portions 212 are located on opposite sides of the electrode assembly 21, the limiting members 25 on opposite sides of the electrode assembly 21 can both apply a force pointing towards the inside of the housing 22 to the bent portion 212. At this time, in addition to limiting the expansion of the bent portion 212, the limiting member 25 can also play a role in assisting in fixing the electrode assembly 21.

[0139] In this embodiment, the limiting member 25 is made to abut against the bent portion 212 so that the limiting member 25 can further limit the expansion deformation amount of the electrode assembly 21; at the same time, the limiting member 25 can also play a role in assisting in fixing the electrode assembly 21.

[0140] Reference Figure 9 , in some embodiments, the limiting member 25 is an elastic member, and the maximum deformation amount of the limiting member 25 is less than the distance between the second wall 224 and the flat portion 211.

[0141] The limiting member 25 is an elastic member, that is, the limiting member 25 has a certain deformation ability and a certain deformation amount under the action of an external force; the material of the limiting member 25 can include rubber, elastic fibers or other materials; a plurality of cavities can be provided inside the limiting member 25 to form a porous structure to facilitate the deformation of the limiting member 25.

[0142] The maximum deformation amount of the limiting member 25 refers to: when the limiting member 25 deforms under the action of an external force, the maximum value of the deformation amount of the limiting member 25 in the direction of the external force. After the limiting member 25 deforms to the maximum deformation amount, further increasing the external force will not cause further deformation of the limiting member 25.

[0143] The maximum deformation amount of the limiting member 25 can be measured in various ways. For example, image information can be collected through microscope observation and analyzed by image processing software, or it can be measured by a laser displacement sensor, or by pasting a strain gauge on the limiting member 25 and measuring the resistance change of the strain gauge; it can be understood that the deformation amount of the limiting member 25 can also be measured by other methods, not limited to the above several. For example, after determining the measurement method, an external force is applied to the limiting member 25 to make the limiting member 25 gradually deform. At this time, the deformation amount of the limiting member 25 is measured by the determined measurement method. When the limiting member 25 is difficult to further deform, the measured deformation amount is the maximum deformation amount of the limiting member 25.

[0144] When the battery cell 20 expands, the bending portion 212 expands and can abut against the limiting member 25. At this time, when the bending portion 212 continues to expand, it can apply a force to the limiting member 25, and this force can deform the limiting member 25. Accordingly, making the maximum deformation amount of the limiting member 25 less than the distance between the second wall 224 and the flat portion 211 can limit the expansion deformation amount of the bending portion 212, so that the expansion deformation amount of the bending portion 212 can be less than the expansion deformation amount of the flat portion 211, so as to reduce the difference between the expansion deformation amount of the bending portion 212 and the expansion deformation amount of the flat portion 211, thereby reducing the stress concentration at the bending portion 212 and the connecting portion between the bending portion 212 and the flat portion 211.

[0145] In this embodiment, making the maximum deformation amount of the limiting member 25 less than the distance between the second wall 224 and the flat portion 211, when the electrode assembly 21 expands, this setting can limit the expansion deformation amount of the bending portion 212, and can provide a larger space for the expansion of the flat portion 211, so as to reduce the difference between the expansion deformation amount of the bending portion 212 and the expansion deformation amount of the flat portion 211, and can release the expansion force of the electrode assembly 21 to the flat portion 211, thereby reducing the expansion force on the bending portion 212, and can alleviate the problem that the connecting portion between the bending portion 212 and the flat portion 211 is prone to breakage, and can also alleviate the stress concentration of the bending portion 212.

[0146] Reference Figure 4 、 Figure 5 、 Figure 7 、 Figure 9 In some embodiments, there are two first walls 223 and two second walls 224. The two first walls 223 and the two second walls 224 are alternately connected end to end in sequence and enclose a first accommodation cavity 221 for accommodating at least a part of the electrode assembly 21.

[0147] There are two first walls 223 and two second walls 224, and the two first walls 223 and the two second walls 224 are alternately connected end to end in sequence. For example, the two first walls 223 are oppositely arranged, and the two second walls 224 are oppositely arranged. The two sides of the second wall 224 along the length direction X of the battery cell 20 are respectively connected to the two first walls 223, and the two sides of the first wall 223 along the width direction Y of the battery cell 20 are respectively connected to the two second walls 224.

[0148] The two first walls 223 and the two second walls 224 are alternately connected end to end in sequence to form the side structure of the housing 22 and enclose the first accommodation cavity 221. The first accommodation cavity 221 refers to the space in the housing 22 for accommodating the battery cell 20. The electrode assembly 21 can be completely accommodated in the first accommodation cavity 221, or only partially accommodated in the first accommodation cavity 221.

[0149] It can be understood that the housing 22 may only include the first accommodation cavity 221 to accommodate the electrode assembly 21, and the electrode assembly 21 is completely accommodated in the first accommodation cavity 221. At this time, the end cap 23 and the bottom plate are arranged on both sides of the first wall 223 and the second wall 224 along the height direction Z of the battery cell 20 to close the first accommodation cavity 221, and the external structure of the battery cell 20 can be formed. It can be understood that the housing 22 may also include other structures and form other accommodation spaces. At this time, the electrode assembly 21 may only be partially accommodated in the first accommodation cavity 221.

[0150] The surface of the first wall 223 opposite to the arc surface 2231 faces outside the housing 22. This surface may be a surface parallel to the arc surface 2231 or a flat surface. To reduce the thickness of the first wall 223 and improve the energy density of the battery cell 20, the surface of the first wall 223 opposite to the arc surface 2231 may have the same shape as and be parallel to the arc surface 2231. At this time, the housing 22 is arc-shaped at the first wall 223.

[0151] Reference Figure 11 、 Figure 13 In some embodiments, the first accommodation cavity 221 is a space with at least one open side. The housing 22 further includes a sub-housing 226. The sub-housing 226 is arranged on at least one side of the first wall 223 and on the open side of the first accommodation cavity 221. A second accommodation cavity 222 is provided in the sub-housing 226, and the second accommodation cavity 222 communicates with the first accommodation cavity 221.

[0152] The sub-housing 226 refers to a component in the housing 22 for forming the internal environment of the battery cell 20. The shape of the sub-housing 226 may be a cuboid shape, a cylindrical shape or other shapes. The shape of the sub-housing 226 may also be set according to the shape of the battery cell 20. The material of the sub-housing 226 may include metal, plastic or other materials. The material of the sub-housing 226 may also be set according to the material of the first wall 223.

[0153] There may be one sub-housing 226 arranged on one side of the first wall 223, or there may be two sub-housings 226 arranged on opposite sides of the first wall 223. The sub-housing 226 is connected to the first wall 223. The sub-housing 226 may be connected to the first wall 223 by welding, bonding or other means. The sub-housing 226 may also be connected to the second wall 224.

[0154] Different from the first accommodation cavity 221 surrounded by the first wall 223 and the second wall 224, a second accommodation cavity 222 is provided in the sub-housing 226. The second accommodation cavity 222 may be a cuboid-shaped space, a cylindrical-shaped space or a space of other shapes. The second accommodation cavity 222 may be used to accommodate the electrode assembly 21 or other structures in the battery cell 20. The second accommodation cavity 222 may also be used to accommodate the electrolyte.

[0155] The sub-housing 226 is provided on the opening side of the first accommodation cavity 221, such that the second accommodation cavity 222 can communicate with the first accommodation cavity 221, enabling the electrolyte to flow between the first accommodation cavity 221 and the second accommodation cavity 222, and also enabling different parts of the electrode assembly 21 to be respectively accommodated in the first accommodation cavity 221 and the second accommodation cavity 222.

[0156] The first accommodation cavity 221 can have only one opening side, in which case there is also only one sub-housing 226 provided on one side of the first wall 223; the first accommodation cavity 221 can also have two opening sides, in which case there are two sub-housings 226 provided on opposite sides of the first wall 223 respectively.

[0157] Exemplarily, the shape of the sub-housing 226 can be adapted to the end cap 23 or the bottom plate of the battery cell 20; when the surface of the first wall 223 facing outside the housing 22 is an arc surface, the side wall structure of the housing 22 formed by the first wall 223 and the second wall 224 is not easily adapted to the rectangular parallelepiped-shaped end cap 23 and the bottom plate. Therefore, the sub-housing 226 is provided to adapt to the shapes of the end cap 23 and the bottom plate, and at the same time, it can also increase the internal space of the battery cell 20 to accommodate the electrolyte, thereby alleviating the problem of performance degradation of the battery cell 20 that may be caused by insufficient electrolyte.

[0158] In this embodiment, the sub-housing 226 is provided on at least one side of the first wall 223, and the second accommodation cavity 222 of the sub-housing 226 can communicate with the first accommodation cavity 221, so as to increase the space for accommodating the electrolyte and improve the performance of the battery 100; at the same time, when the first wall 223 and the second wall 224 form a special-shaped structure, the sub-housing 226 can be adapted to the top cover or other structures to facilitate the processing and assembly of the housing 22.

[0159] Reference Figure 11 、 Figure 13 , in some embodiments where the housing 22 further includes the sub-housing 226, at least part of the electrode assembly 21 is accommodated in the second accommodation cavity 222.

[0160] When there is one sub-housing 226, one end of the electrode assembly 21 can extend into the second accommodation cavity 222, so that part of the electrode assembly 21 can be accommodated in the second accommodation cavity 222; when there are two sub-housings 226, both ends of the electrode assembly 21 can extend into the two second accommodation cavities 222 respectively, so that part of the electrode assembly 21 can be accommodated in the second accommodation cavity 222.

[0161] When the housing 22 includes the sub-housing 226, this setting enables the second accommodation cavity 222 to also be used to accommodate the electrode assembly 21, so as to improve the space utilization rate in the second accommodation cavity 222, thereby reducing the vacant space inside the housing 22 and increasing the energy density of the battery cell 20.

[0162] Reference Figure 11 、 Figure 13 In some embodiments where the housing 22 further includes a sub-housing 226, in the arrangement direction of the sub-housing 226 and the first wall 223, the size of the first wall 223 is smaller than the size of the electrode assembly 21, and the difference between the size of the electrode assembly 21 and the size of the first wall 223 is less than or equal to 2 mm (millimeters).

[0163] When the sub-housing 226 is disposed on one side of the first wall 223 along the height direction Z of the battery cell 20, the arrangement direction of the sub-housing 226 and the first wall 223 is the height direction Z of the battery cell 20; the sub-housing 226 can also be disposed on one side of the first wall 223 along the length direction X of the battery cell 20, and the sub-housing 226 can also be disposed on one side of the first wall 223 along other directions.

[0164] When the sub-housing 226 is disposed on one side of the first wall 223 along the height direction Z of the battery cell 20, the size of the first wall 223 refers to the size of the first wall 223 in the height direction Z of the battery cell 20, and the size of the electrode assembly 21 refers to the size of the electrode assembly 21 in the height direction Z of the battery cell 20; make the size of the first wall 223 smaller than the size of the electrode assembly 21, that is, at least part of the electrode assembly 21 extends into the second accommodation cavity 222 in the height direction Z of the battery cell 20.

[0165] When the housing 22 includes the sub-housing 226, this setting can enable the second accommodation cavity 222 to also accommodate the electrode assembly 21, so as to improve the space utilization rate in the second accommodation cavity 222, thereby reducing the vacant space inside the housing 22 and improving the energy density of the battery cell 20.

[0166] When the sub-housing 226 is disposed on one side of the first wall 223 along the height direction Z of the battery cell 20, since the sizes of the positive electrode plate and the negative electrode plate in the electrode assembly 21 in the height direction Z of the battery cell 20 are not the same, and the size of the positive electrode plate in the height direction Z of the battery cell 20 is usually smaller than that of the negative electrode plate in the height direction Z of the battery cell 20, that is, the two sides of the negative electrode plate in the height direction Z of the battery cell 20 usually exceed the positive electrode plate, so the part where the electrode assembly 21 exceeds the positive electrode plate in the negative electrode plate usually has a smaller expansion force and a smaller expansion deformation amount.

[0167] Accordingly, make the difference between the height of the electrode assembly 21 and the height of the first wall 223 less than 2 mm. When the electrode assembly 21 expands, this setting can enable the electrode assembly 21 not to easily have stress concentration at the edge of the first wall 223 in the height direction Z, so that the first wall 223 can not only limit the expansion deformation amount of the electrode assembly 21, but also reduce the negative impact on the energy density of the battery cell 20.

[0168] Exemplarily, the difference between the size of the electrode assembly 21 and the size of the first wall 223 can be 2 mm, 1.8 mm, 1.6 mm, 1.4 mm, 1.2 mm, 1 mm, 0.6 mm, 0.4 mm, 0.2 mm or other values.

[0169] In this embodiment, the size of the first wall 223 in the arrangement direction of the sub - housing 226 and the first wall 223 is made smaller than the size of the electrode assembly 21, so that a part of the electrode assembly 21 can enter the second accommodation cavity 222, thereby reducing the overall volume of the housing 22 and increasing the energy density of the battery cell 20; the technical solution of this embodiment also limits the size relationship between the first wall 223 in the arrangement direction of the sub - housing 226 and the first wall 223 and the size of the electrode assembly 21. In the case of the expansion of the electrode assembly 21, this setting can reduce the stress concentration at the edge of the first wall 223 of the electrode assembly 21.

[0170] Reference Figure 12 , in some embodiments where the housing 22 further includes a sub - housing 226, the battery cell 20 further includes an end plate 227, and the end plate 227 is provided on the side of the sub - housing 226 facing away from the first wall 223.

[0171] The end plate 227 refers to a structure that can cooperate with the housing 22 to isolate the internal environment of the battery cell 20 from the external environment; the shape of the end plate 227 can be square, circular or other shapes, and the shape of the end plate 227 can also be set according to the structure of the adjacent housing 22; the material of the end plate 227 can include metal, plastic or other materials.

[0172] Since the sub - housing 226 is provided on one side of the first wall 223, the end plate 227 can be provided on the side of the sub - housing 226 facing away from the first wall 223, that is, the end plate 227 can cover the sub - housing 226 and isolate the second accommodation cavity 222 from the external environment of the battery cell 20.

[0173] When the sub - housing 226 is arranged above the first wall 223 along the height direction Z of the battery cell 20, the end plate 227 is arranged above the sub - housing 226. At this time, the end plate 227 can be used as the end cover 23 of the battery cell 20; when the sub - housing 226 is arranged below the first wall 223 along the height direction Z of the battery cell 20, the end plate 227 is arranged below the sub - housing 226. At this time, the end plate 227 can be used as the bottom plate of the battery cell 20.

[0174] When the sub - housing 226 is arranged above and below the first wall 223 respectively along the height direction Z of the battery cell 20, there are two end plates 227, and they are respectively arranged on the sides of the two sub - housings 226 away from the first wall 223, so as to isolate the first accommodation cavity 221 and the second accommodation cavity 222 from the external environment of the battery cell 20.

[0175] In this embodiment, the end plate 227 is covered on the side of the sub-housing 226 facing away from the first wall 223, so as to cooperate with the housing 22 and the sub-housing 226 to enclose a closed accommodation space.

[0176] Reference Figure 14 、 Figure 15 Referring to, in some embodiments, the housing 22 further includes a third wall 225 connected to the second wall 224. The third wall 225 is located on the side of the first wall 223 facing away from the first accommodation cavity 221. A third accommodation cavity 2261 is formed between the first wall 223, the two second walls 224 and the third wall 225, and the third accommodation cavity 2261 communicates with the first accommodation cavity 221.

[0177] The third wall 225 refers to a partial structure of the housing 22. The third wall 225 can be a structure of the housing 22 exposed to the external environment of the battery cell 20, or can also be a structure located inside the battery cell 20. The shape of the third wall 225 can be rectangular, circular or other shapes, and the shape of the third wall 225 can also be set according to the shape of the housing 22. The material of the third wall 225 can include metal, plastic or other materials, and the material of the third wall 225 can also be set according to the material of the housing 22.

[0178] The third wall 225 is connected to the second wall 224. The third wall 225 can be directly connected to the second wall 224, or can be indirectly connected to the second wall 224 through an intermediate structure. In the case where the third wall 225 is directly connected to the second wall 224, the third wall 225 can be connected to the second wall 224 by welding, gluing or other means, or the third wall 225 and the second wall 224 can be integrally formed.

[0179] The third wall 225 is provided on the side of the first wall 223 facing away from the first accommodation cavity 221, that is, the first wall 223 is located inside the third wall 225. In the case where the second wall 224 and the third wall 225 are connected to form the external structure of the housing 22, the first wall 223 is located inside the battery cell 20.

[0180] On both sides of the third wall 225, it is respectively connected to two second walls 224. At this time, the third wall 225, a part of the two second walls 224, and the first wall 223 can enclose a third accommodation cavity 2261; the third accommodation cavity 2261 is communicated with the first accommodation cavity 221. The third accommodation cavity 2261 can be communicated with the first accommodation cavity 221 through a pipe fitting, or a through hole can be provided on the first wall 223 to communicate the first accommodation cavity 221 and the third accommodation cavity 2261, or the first accommodation cavity 221 and the third accommodation cavity 2261 can be communicated in other ways; the electrolyte can flow in the first accommodation cavity 221 and the third accommodation cavity 2261, so that there is a larger accommodation space for the electrolyte inside the battery cell 20, thereby alleviating the problem of insufficient electrolyte and reducing the negative impact of the amount of electrolyte on the performance of the battery cell 20.

[0181] The setting of the third wall 225 enables the housing 22 formed by the third wall 225 and the second wall 224 to be in a cuboid shape or other regular shapes commonly used for the battery cell 20, so as to facilitate the housing 22 to adapt to other structures of the battery cell 20 (such as the end cap 23, etc.); it can be understood that in order to improve the energy density of the battery cell 20, the surface of the first wall 223 facing away from the arc surface 2231 can be abutted against the third wall 225.

[0182] Exemplarily, the second walls 224 are arranged at intervals along the width direction Y of the battery cell 20, and the third wall 225 is arranged at intervals along the length direction X of the battery cell 20. At this time, the two first walls 223 are located between the two third walls 225, and the electrode assembly 21 is located between the two first walls 223; at this time, third accommodation cavities 2261 are provided on both sides of the first accommodation cavity 221 along the length direction X of the battery cell 20.

[0183] In this embodiment, the housing 22 includes a third wall 225, so that the third wall 225 can cooperate with the second wall 224 to enclose the internal space of the housing 22. At this time, the first wall 223 is located inside the housing 22. This setting can make the shape of the housing 22 a common shape to meet the requirements of other structures and reduce the negative impact on the processing and assembly of the battery 100; at the same time, the third wall 225 can also cooperate with the first wall 223 and the second wall 224 to form a third accommodation cavity 2261 and communicate the third accommodation cavity 2261 with the first accommodation cavity 221 to increase the accommodation space for the electrolyte and improve the performance of the battery cell 20.

[0184] Reference Figure 15 In some embodiments where the housing 22 includes a third wall 225, a first through hole 2232 is provided on the first wall 223 to communicate the first accommodation cavity 221 and the third accommodation cavity 2261.

[0185] The first through-hole 2232 refers to a hole structure formed in the first wall 223. The first through-hole 2232 can be a straight hole, a stepped hole or a hole structure of other shapes, and the first through-hole 2232 can be a round hole, a square hole or a hole structure of other shapes; the number of the first through-holes 2232 can be one, or two or more.

[0186] The first through-hole 2232 can communicate the first accommodation cavity 221 and the third accommodation cavity 2261, so that the electrolyte can flow between the first accommodation cavity 221 and the third accommodation cavity 2261; for example, the first through-hole 2232 can be provided below the first wall 223 in its height direction Z to facilitate the flow of the electrolyte.

[0187] This embodiment provides some ways for the third accommodation cavity 2261 to communicate with the first accommodation cavity 221, so that the battery cell 20 can have a larger electrolyte accommodation space.

[0188] Reference Figure 15 Referring to, in some embodiments where the housing 22 includes the third wall 225, in the length direction of the first wall 223, the size of the third wall 225 is equal to the size of the second wall 224, and the size of the first wall 223 is smaller than the size of the second wall 224.

[0189] The length direction of the first wall 223 can be the height direction Z of the battery cell 20, or the length direction X of the battery cell 20, or the arrangement direction of the sub-housing 226 and the first wall 223 or other directions; when the length direction of the first wall 223 is the height direction of the battery cell 20, the sizes of the first wall 223, the second wall 224, and the third wall 225 are respectively the sizes of the three in the height direction Z of the battery cell 20; the size of the third wall 225 is equal to the size of the second wall 224, so that the second wall 224 and the third wall 225 are flush or relatively flush on both sides in the height direction Z of the battery cell 20 to facilitate the installation of other structures.

[0190] The size of the first wall 223 is smaller than the size of the second wall 224. When the bottom plate and the end cover 23 are installed on the housing 22, the height of the first wall 223 being smaller than the height of the second wall 224 can make there be a gap between one side of the first wall 223 in the height direction Z and the end cover 23 and / or the bottom plate. At this time, the electrolyte can flow between the first accommodation cavity 221 and the third accommodation cavity 2261 through this gap.

[0191] To facilitate the communication between the first accommodation cavity 221 and the third accommodation cavity 2261, the first through-hole 2232 can be provided only on the first wall 223, or only the height of the first wall 223 can be made smaller than the height of the second wall 224, or the first through-hole 2232 can be provided on the first wall 223 on the basis that the height of the first wall 223 is smaller than the height of the second wall 224.

[0192] This embodiment provides another way for the third accommodation cavity 2261 to communicate with the first accommodation cavity 221, so that the battery cell 20 can have a larger electrolyte accommodation space.

[0193] Reference Figure 15 , in some embodiments where the housing 22 includes the third wall 225, in the length direction of the first wall 223, the difference between the size of the first wall 223 and the size of the second wall 224 is less than or equal to 2 mm.

[0194] The length direction of the first wall 223 can be the height direction Z of the battery cell 20, the length direction X of the battery cell 20, the arrangement direction of the sub-housing 226 and the first wall 223, or other directions; when the length direction of the first wall 223 is the height direction of the battery cell 20, the difference between the size of the second wall 224 and the size of the first wall 223 is less than or equal to 2 mm. For example, the difference between the size of the electrode assembly 21 and the size of the first wall 223 can be 2 mm, 1.8 mm, 1.6 mm, 1.4 mm, 1.2 mm, 1 mm, 0.6 mm, 0.4 mm, 0.2 mm, or other values.

[0195] When the length direction of the first wall 223 is the height direction Z of the battery cell 20, since the sizes of the positive electrode plate and the negative electrode plate in the electrode assembly 21 in the height direction Z of the battery cell 20 are not the same, and the size of the positive electrode plate in the height direction Z of the battery cell 20 is usually smaller than that of the negative electrode plate in the height direction Z of the battery cell 20, that is, the two sides of the negative electrode plate in the height direction Z of the battery cell 20 usually exceed the positive electrode plate, so the part where the negative electrode plate exceeds the positive electrode plate in the electrode assembly 21 usually has a smaller expansion force and a smaller expansion deformation amount.

[0196] Accordingly, making the difference between the size of the second wall 224 in the arrangement direction of the sub-housing 226 and the first wall 223 and the size of the first wall 223 less than 2 mm, when the electrode assembly 21 expands, this setting can prevent the electrode assembly 21 from having stress concentration at the edge of the first wall 223, so that the first wall 223 can not only limit the expansion deformation amount of the electrode assembly 21, but also communicate the first accommodation cavity 221 and the third accommodation cavity 2261.

[0197] This embodiment provides some ways for the third accommodation cavity 2261 to communicate with the first accommodation cavity 221, so that the battery cell 20 can not only have a larger electrolyte accommodation space, but also reduce the stress concentration at the edge of the first wall 223 of the electrode assembly 21.

[0198] Reference Figure 16, in some embodiments, the battery cell 20 further includes a support plate 24, which is received in the first receiving cavity 221 and abuts against the adjacent first wall 223 and second wall 224.

[0199] The support plate 24 refers to a structure located below the electrode assembly 21. The support plate 24 is mainly used to support the electrode assembly 21 and also to insulate the electrode assembly 21 from the housing 22, thereby reducing the short circuit caused by the contact between the electrode assembly 21 and the housing 22 or other structural members. The material of the support plate 24 may include plastics, rubbers, ceramics or other insulating materials.

[0200] The support plate 24 is located in the first receiving cavity 221, and the support plate 24 abuts against the adjacent first wall 223 and second wall 224, that is, the shape of the support plate 24 is adapted to the shapes of the first wall 223 and the second wall 224. At the same time, this setting also enables the support plate 24 to better play an insulating role and reduce the short circuit of the electrode assembly 21 with the housing 22 in the gap between the support plate 24 and the first wall 223 or the second wall 224.

[0201] Exemplarily, when the first wall 223 is a semi-circular plate-like structure, the first wall 223 and the second wall 224 enclose a columnar structure with a racetrack-shaped cross-section. At this time, the support plate 24 is also a plate-like structure with a racetrack shape.

[0202] In this embodiment, the circumferential side of the support plate 24 abuts against the first wall 223 and the second wall 224, so that the shape of the support plate 24 can be adapted to the shapes of the first wall 223 and the second wall 224, facilitating the installation of the support plate 24 and improving the compatibility of the support plate 24.

[0203] Reference Figure 16 , in some embodiments, the support plate 24 is provided with a second through hole 241.

[0204] The second through hole 241 refers to a hole structure formed on the support plate 24. The second through hole 241 can be a straight hole, a stepped hole or other shaped hole structures. The second through hole 241 can be a round hole, a square hole or other shaped hole structures. The number of the second through holes 241 can be one, or two or more.

[0205] In this embodiment, the second through hole 241 is provided on the support plate 24 to facilitate the electrolyte to flow through the support plate 24 and better wet the electrode assembly 21.

[0206] Reference Figure 17 , in some embodiments, the battery cell 20 further includes an insulating film 26, which wraps the electrode assembly 21. The insulating film 26 includes an arc section 261, and the arc section 261 is disposed opposite to the bending portion 212.

[0207] The insulating film 26 refers to the structure in the battery cell 20 mainly used to separate the electrode assembly 21 and the housing 22. The insulating film 26 can reduce the occurrence of short circuits caused by the electrode assembly 21 contacting the housing 22. At the same time, the electrolyte can penetrate through the insulating film 26 and soak the insulating film 26; the material of the insulating film 26 can include polyester fiber or other materials.

[0208] The insulating film 26 wraps the electrode assembly 21. The insulating film 26 can be wound around the circumferential side of the electrode assembly 21, and can also wrap other sides of the electrode assembly 21 to protect the electrode assembly 21 and reduce the occurrence of short circuits caused by the circumferential side of the electrode assembly 21 contacting the first wall 223 and the second wall 224; when the support plate 24 is provided in the first accommodation cavity 221, the insulating film 26 can cooperate with the support plate 24 to better reduce the contact between the electrode assembly 21 and the housing 22.

[0209] The insulating film 26 includes an arc segment 261, and the arc segment 261 is opposite to the bent portion 212 of the electrode assembly 21 so that the insulating film 26 can be adapted to the shape of the electrode assembly 21; because the shape of the electrode assembly 21 is adapted to the shapes of the first wall 223 and the second wall 224, and the insulating film 26 is usually a flexible structure and is wound and attached to the circumferential side of the electrode assembly 21, when the insulating film 26 is wound around the electrode assembly 21, the setting of the arc segment 261 enables the shape of the insulating film 26 to be adapted to the electrode assembly 21 and can be adapted to the first wall 223 and the second wall 224. At the same time, the insulating film 26 can also play a role in restricting the shape of the electrode assembly 21. For example, in the part where the insulating film 26 covers the first wall 223, the arc segment 261 is adapted to the arc surface 2231, and the distance between the arc segment 261 and the arc surface 2231 is equal or approximately equal; in the part where the insulating film 26 covers the second wall 224, the shape of the insulating film 26 is adapted to the second wall 224, that is, the part of the insulating film 26 covering the flat portion 211 is also a plane, and the distance between the surface of the insulating film 26 facing the second wall 224 and the surface of the second wall 224 facing the insulating film 26 is equal or approximately equal.

[0210] It can be understood that the insulating film 26 can also include a flat segment 262. The flat segment 262 is connected to the arc segment 261, and the flat segment 262 is opposite to the flat portion 211 of the electrode assembly 21 so that the insulating film 26 can be adapted to the shape of the electrode assembly 21.

[0211] For example, referring to Figure 17 , when the circumferential sides of the support plate 24 respectively abut against the adjacent first wall 223 and the second wall 224, the insulating film 26 can also be adapted to the support plate 24, that is, at this time, the length W1 of the flat segment 262 is the same or approximately the same as the length of the part of the support plate 24 opposite to the second wall 224, and the length W2 of the arc segment 261 is the same or approximately the same as the length of the part of the support plate 24 opposite to the first wall 223.

[0212] In this embodiment, the shape of the insulating film 26 can be adapted to the shapes of the first wall 223 and the second wall 224, which improves the compatibility of the insulating film 26 and also facilitates the installation of the electrode assembly 21 into the housing 22 after winding the insulating film 26.

[0213] Reference Figures 3 to 6 , in some embodiments, the difference between the maximum width of the housing 22 and the maximum width of the electrode assembly 21 is greater than the difference between the maximum length of the housing 22 and the maximum length of the electrode assembly 21.

[0214] The maximum width of the housing 22 refers to the maximum dimension of the housing 22 in the width direction Y of the battery cell 20, which is the dimension shown as H in Figure 5 ; the maximum width of the electrode assembly 21 refers to the maximum dimension of the electrode assembly 21 in the width direction Y of the battery cell 20, which is the dimension shown as h in Figure 5 ; the difference between the maximum width of the housing 22 and the maximum width of the electrode assembly 21 mainly affects the expansion deformation amount of the flat portion 211 in the housing 22. The larger this difference is, the larger the expansion deformation amount of the flat portion 211 is.

[0215] The maximum length of the housing 22 refers to the maximum dimension of the housing 22 in the length direction X of the battery cell 20, which is the dimension shown as L in Figure 5 ; the maximum length of the electrode assembly 21 refers to the maximum dimension of the electrode assembly 21 in the length direction X of the battery cell 20, which is the dimension shown as l in Figure 5 ; the difference between the maximum length of the housing 22 and the maximum length of the electrode assembly 21 mainly affects the expansion deformation amount of the bending portion 212 in the housing 22. The larger this difference is, the larger the expansion deformation amount of the bending portion 212 is.

[0216] In the case where the battery cell 20 expands, making the difference between the maximum width of the housing 22 and the maximum width of the electrode assembly 21 greater than the difference between the maximum length of the housing 22 and the maximum length of the electrode assembly 21, so that the flat portion 211 has a larger expansion deformation space, while the expansion deformation space of the bending portion 212 is relatively small; accordingly, after the bending portion 212 expands, it can first abut against the first wall 223, and it is not easy for the bending portion 212 to further expand after abutting against the first wall 223. At this time, the expansion force of the battery cell 20 will be transferred to the flat portion 211 and cause the flat portion 211 to further expand. Since the flat portion 211 is relatively flat, the contact area between the flat portion 211 and the second wall 224 during expansion is large, and it is not easy for the flat portion 211 to have stress concentration during expansion, thus achieving the effect of alleviating the fracture of the electrode assembly 21.

[0217] In this embodiment, the difference between the maximum width of the housing 22 and the maximum width of the electrode assembly 21 is greater than the difference between the maximum length of the housing 22 and the maximum length of the electrode assembly 21. When the electrode assembly 21 expands, this setting can limit the expansion deformation amount of the bending portion 212, and can provide a larger space for the expansion of the flat portion 211, so as to reduce the difference between the expansion deformation amount of the bending portion 212 and the expansion deformation amount of the flat portion 211, and can release the expansion force of the electrode assembly 21 to the flat portion 211, thereby reducing the expansion force on the bending portion 212, and can alleviate the problem that the connection part between the bending portion 212 and the flat portion 211 is prone to fracture, and can also alleviate the stress concentration of the bending portion 212.

[0218] Reference Figures 4 to 6 , in some embodiments, the distance between the second wall 224 and the flat portion 211 is greater than the distance between the arc surface 2231 and the bending portion 212.

[0219] The distance between the second wall 224 and the flat portion 211 refers to: the distance between the surface of the second wall 224 facing the electrode assembly 21 and the flat portion 211 when the battery cell 20 is in the natural state of not being used, that is, the dimension shown as H1 in the figure.

[0220] The distance between the arc surface 2231 and the bending portion 212 refers to: the distance between the surface of the arc surface 2231 facing the electrode assembly 21 and the bending portion 212 when the battery cell 20 is in the natural state of not being used, that is, the dimension shown as L1 in the figure; when both the bending portion 212 and the arc surface 2231 are semi-circular, this distance is also the difference between the radii of the bending portion 212 and the arc surface 2231.

[0221] It can be understood that since an electrode assembly 21 usually has two flat portions 211 and two bending portions 212, the distance between the second wall 224 and the flat portion 211 can be the distance between any flat portion 211 and the adjacent second wall 224, and the distance between the arc surface 2231 and the bending portion 212 can be the distance between any bending portion 212 and the adjacent arc surface 2231.

[0222] The distance between the second wall 224 and the flat portion 211 is greater than the distance between the arc surface 2231 and the bending portion 212, that is, H1 is greater than L1; this setting can make the electrode assembly 21 located at the central position inside the housing 22. When the battery cell 20 expands, this setting can reduce problems such as unbalanced force and excessive local force on the electrode assembly 21 that may be caused by one side of the electrode assembly 21 abutting against the inner wall of the housing 22 earlier than other positions.

[0223] In this embodiment, the dimensional relationship between the bending portion 212, the flat portion 211 and the adjacent wall surfaces is further restricted to alleviate the problems of stress concentration and local easy fracture of the electrode assembly 21; meanwhile, this setting can also enable the electrode assembly 21 to be located in the middle of the housing 22, thereby reducing the problem of local stress concentration caused by the position offset of the electrode assembly 21.

[0224] In some embodiments, the battery cell 20 includes a housing 22 and a battery cell 20, and the battery cell 20 includes a flat portion 211 and a bending portion 212.

[0225] The housing 22 includes two first walls 223 spaced apart along the length direction X of the battery cell 20, and two second walls 224 spaced relatively apart along the width direction Y of the battery cell 20. The two first walls 223 and the two second walls 224 are alternately connected in sequence to enclose a first accommodation cavity 221, and the battery cell 20 is accommodated in the first accommodation cavity 221.

[0226] The first wall 223 faces the bending portion 212. The arc surface 2231 of the first wall 223 is an arc surface, and the arc surface 2231 is substantially the same shape as the bending portion 212; the second wall 224 faces the flat portion 211. The distance between the second wall 224 and the flat portion 211 is greater than the distance between the first wall 223 and the bending portion 212.

[0227] The housing 22 further includes a third wall 225. The third wall 225 is spaced along the length direction X of the battery cell 20, and both of the two first walls 223 are located between the two third walls 225; the two second walls 224 and the two third walls 225 are connected end to end in sequence to enclose the internal space of the battery cell 20; the third wall 225, a part of the two second walls 224 and the first wall 223 can also enclose a third accommodation cavity 2261.

[0228] The height of the first wall 223 is less than the height of the second wall 224 so that the third accommodation cavity 2261 can communicate with the first accommodation cavity 221.

[0229] In a second aspect, an embodiment of the present application further provides a battery 100, including the battery cell 20 provided by some embodiments of the first aspect; in such a battery 100, the electrode assembly 21 of the battery cell 20 is not easily broken due to expansion during use, so that the battery 100 can have high stability and good performance.

[0230] In a third aspect, an embodiment of the present application further provides an electrical device, including the battery 100 provided by some embodiments of the second aspect; in such an electrical device, the battery 100 has better stability, the performance of the battery 100 is not easily greatly reduced, and it is not easy to have situations such as thermal runaway leading to fire.

[0231] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: An electrode assembly, the electrode assembly comprising a flat portion and a curved portion connected to the flat portion; A shell is used to accommodate the electrode assembly, the shell includes a first wall and a second wall connected to the first wall, the first wall is arranged opposite to the curved portion, the second wall is arranged opposite to the flat portion, the first wall includes an arcuate surface opposite to the curved portion, and the arcuate surface is adapted to the side surface of the curved portion.

2. The battery cell according to claim 1, wherein The number of the electrode assemblies is at least two, and the plurality of electrode assemblies are arranged along the width direction of the battery cell, and two adjacent flat portions are disposed opposite to each other.

3. The battery cell according to claim 2, wherein The first wall includes at least two arc-shaped surfaces arranged along the width direction of the battery cell, and each of the arc-shaped surfaces is opposite to the adjacent curved portions.

4. The battery cell according to claim 2, wherein, A limiting member is provided between the bent portions of two adjacent electrode assemblies.

5. The battery cell according to claim 4, characterized in that, The limiting member is disposed at a distance from the bending portion on one side facing the bending portion.

6. The battery cell according to claim 5, wherein, The distance between the side of the limiting member facing the curved portion and the corresponding curved portion is smaller than the distance between the second wall and the flat portion.

7. The battery cell according to claim 4, characterized in that, The limiting member abuts against the bent portion.

8. The battery cell according to any one of claims 4-7, characterized in that, The limiting member is an elastic member, and a maximum deformation amount of the limiting member is smaller than a distance between the second wall and the flat portion.

9. The battery cell according to claim 1, wherein There are two of the first wall and the second wall, and the two first walls and the two second walls are alternately connected end to end to form a first accommodating cavity, and the first accommodating cavity is used to accommodate at least part of the electrode assembly.

10. The battery cell according to claim 9, characterized in that, The first accommodating cavity is a space with at least one side open; The housing further comprises a sub-housing, wherein the sub-housing is arranged on at least one side of the first wall and on an opening side of the first accommodating cavity; A second accommodating chamber is provided in the sub-shell, and the second accommodating chamber is communicated with the first accommodating chamber.

11. The battery cell according to claim 10, wherein, At least a portion of the electrode assembly is accommodated in the second accommodation cavity.

12. The battery cell according to claim 10 or 11, characterized in that, In the arrangement direction of the subshell and the first wall, the size of the first wall is smaller than the size of the electrode assembly, and the difference between the size of the electrode assembly and the size of the first wall is less than or equal to 2 mm.

13. The battery cell according to claim 10, wherein, The battery cell further includes an end plate, and the end plate is arranged on a side of the sub-housing away from the first wall.

14. The battery cell according to claim 9, characterized in that, The housing further comprises a third wall connected to the second wall, wherein the third wall is located on a side of the first wall away from the first accommodating cavity; The first wall, the two second walls and the third wall form a third accommodating cavity, and the third accommodating cavity is communicated with the first accommodating cavity.

15. The battery cell according to claim 14, wherein The first wall is provided with a first through hole to connect the first accommodating cavity and the third accommodating cavity.

16. The battery cell according to claim 14, wherein, In the length direction of the first wall, the size of the third wall is equal to the size of the second wall, and the size of the first wall is smaller than the size of the second wall.

17. The battery cell according to claim 16, wherein, In the length direction of the first wall, a difference between a size of the first wall and a size of the second wall is less than or equal to 2 mm.

18. The battery cell according to claim 9, wherein, The battery cell further includes a support plate, which is disposed in the first accommodating cavity and abuts against the adjacent first wall and the second wall.

19. The battery cell according to claim 18, wherein The supporting plate is provided with a second through hole.

20. The battery cell according to claim 9, characterized in that, The battery cell further includes an insulating film, the insulating film wraps the electrode assembly, the insulating film includes an arc section, and the arc section is disposed opposite to the bent portion.

21. The battery cell according to claim 1, characterized in that, The difference between the maximum width of the housing and the maximum width of the electrode assembly is greater than the difference between the maximum length of the housing and the maximum length of the electrode assembly.

22. The battery cell according to claim 21, wherein, The distance between the second wall and the flat portion is greater than the distance between the arc surface and the bent portion.

23. A battery, characterized in that, A battery cell including any one of claims 1-22.

24. An electrical device, characterized in that, A battery including claim 23.

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