Battery cell, battery device, energy storage device, and electric device

Abstract

The application relates to the technical field of batteries, and provides a battery monomer, a battery device, an energy storage device and an electric equipment. The battery monomer comprises: a shell comprising a shell body and an end cover, the shell body is provided with a containing cavity, the containing cavity has an opening, and the end cover covers the opening; and an electrode assembly accommodated in the containing cavity; wherein the shell is locally recessed in a direction close to the electrode assembly to form at least one recess, and a wall surface of the recess is a curved surface. According to the technical scheme, the anti-deformation ability of the shell of the battery monomer can be improved, the risk that the connecting area of the shell and the end cover is cracked due to stress concentration caused by excessive internal pressure of the battery monomer is reduced, and the use stability of the battery monomer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery device, an energy storage device and an electric equipment. BACKGROUND

[0002] The part provided in this part is only background information related to the present disclosure, which is not necessarily prior art.

[0003] At present, the capacity demand of the battery device is getting larger and larger, and the size of the shell of the battery monomer is also getting larger and larger, which leads to poor deformation resistance of the shell, insufficient mechanical strength, and further leads to deformation of the shell of the battery monomer under cyclic charging and discharging or mechanical impact, and stress concentration at the welding seam of the shell, affecting the service stability of the welding seam and the battery monomer. UTILITY MODEL CONTENT

[0004] The purpose of the present application is to provide a battery monomer, a battery device, an energy storage device and an electric equipment, so as to improve the deformation resistance of the shell of the battery monomer and improve the service stability of the battery monomer. The purpose is achieved by the following technical solutions:

[0005] In a first aspect, the present application provides a battery monomer, comprising: an outer shell comprising a shell and an end cover, the shell being provided with a containing cavity, the containing cavity having an opening, and the end cover being capped on the opening; an electrode assembly accommodated in the containing cavity through the opening; wherein the shell is locally recessed in the direction close to the electrode assembly to form at least one recess, and the wall surface of the recess is a curved surface.

[0006] According to the battery monomer provided by the present application, at least one recess is arranged on the shell, the recess is formed by locally recessing the surface of the shell in the direction of the electrode assembly, and the wall surface of the recess is arranged as a curved surface. In this way, when the battery monomer is in the charging and discharging process, the electrode assembly expands and can act the generated expansion force on the area where the recess is located. The area where the recess is located can play a role in buffering the expansion force and can make the expansion force uniformly transmitted to other areas of the shell along the curved surface of the recess, so as to reduce the risk of deformation of the whole shell and reduce the stress concentration coefficient of the connecting area between the shell and the end cover, thereby reducing the risk of cracking of the connecting area due to stress concentration and improving the service stability of the battery monomer.

[0007] In addition, the battery monomer provided by the present application can also have the following additional technical features:

[0008] In some embodiments of the present application, the shell has a first wall surface, which is the largest surface area in the shell, and a plurality of recesses are arranged on the first wall surface in the circumferential direction of the shell and extend from one side to the other side of the shell having the opening.

[0009] In the above technical solution, the expansion force generated by the electrode assembly during the expansion of the electrode assembly in the charging and discharging process corresponds to the first wall surface of the shell. Therefore, by arranging a plurality of recesses on the first wall surface of the shell and extending in the height direction of the shell, the expansion force generated by the electrode assembly can be applied to the plurality of recesses, respectively. The plurality of recesses buffer the expansion force generated by the electrode assembly and disperse the expansion force to other areas of the shell, thereby improving the overall fatigue strength of the shell and further reducing the risk of deformation of the shell as a whole.

[0010] In some embodiments of the present application, each of the recesses has a first surface facing the electrode assembly, which protrudes into the accommodation cavity and is in contact with the electrode assembly.

[0011] In the above technical solution, when the electrode assembly is installed in the accommodation cavity of the shell, it is directly in contact with the first surfaces of the plurality of recesses, so that the plurality of recesses can fix the electrode assembly to reduce the risk of shaking of the electrode assembly in the shell and improve the stability and reliability of the installation of the electrode assembly. In addition, the direct contact between the electrode assembly and the first surfaces of the plurality of recesses can shorten the heat conduction path between the electrode assembly and the shell, which helps to improve the overall temperature regulation efficiency of the battery monomer.

[0012] In some embodiments of the present application, a heat dissipation channel is formed between two adjacent recesses and the electrode assembly.

[0013] In the above technical solution, the battery monomer generates gas during the charging and discharging process. The gas can flow in an orderly manner in the direction close to the end cover through the heat dissipation channel formed between the two adjacent recesses and the electrode assembly, which not only reduces the local pressure rise caused by the accumulation of gas in the local area of the shell, but also provides a pre-flow path for the opening of the pressure relief mechanism arranged on the end cover, thereby further improving the stability of the use of the battery monomer.

[0014] In some embodiments of the present application, the area between two adjacent recesses in the first wall surface is a flat surface, and the edge of the recess is connected to the flat surface through a circular arc transition.

[0015] In the above technical solution, the edge of the recess and the flat surface are connected through a circular arc transition, thereby reducing the risk of excessive deformation or cracking of the connection between the edge of the recess and the flat surface due to stress concentration.

[0016] In some embodiments of this application, the wall thickness of the housing corresponding to the region where the recess is located is the same as the wall thickness of the region corresponding to the plane.

[0017] In the above technical solution, the recess can be integrally formed by stamping. The wall thickness of the recess area is consistent with the wall thickness of the flat area in the shell, which can improve the material utilization rate when processing the shell. Compared with the solution of thinning the wall thickness of the recess area, it helps to improve the rigidity and fatigue strength of the recess area.

[0018] In some embodiments of this application, the recess further has a second surface, which is a side surface of the recess away from the electrode assembly, and the second surface is arranged parallel to the first surface.

[0019] In the above technical solution, the second surface is a surface of the concave portion that is away from the electrode assembly. The second surface is arranged parallel to the first surface, that is, the second surface is also a curved surface, which is convenient for processing and forming, and also makes it convenient to use the concave portion to buffer the expansion force generated when the electrode assembly expands.

[0020] In some embodiments of this application, the radius of curvature of the first surface is set in the range of 90mm-100mm.

[0021] In the above technical solution, by setting the radius of curvature of the first surface in the range of 90mm-100mm, it is not only easy to process and form, but also makes the concave surface relatively flat, which helps to improve the uniformity of stress dispersion by utilizing the first surface.

[0022] In some embodiments of this application, the center distance between two adjacent recesses is set in the range of 40mm-50mm.

[0023] In the above technical solution, by setting the center distance between two adjacent recesses in the range of 40mm-50mm, the heat dissipation channel formed by the two adjacent recesses and the electrode assembly is relatively large, so that the gas in the housing can be quickly discharged to the end cap side along the heat dissipation channel. It also helps to further improve the fatigue strength of the housing, so as to further reduce the risk of deformation of the housing due to stress concentration.

[0024] In some embodiments of this application, along the extending direction of the recess, a first gap is provided between one end of the recess and the side of the housing with the opening, and a second gap is provided between the other end of the recess and the side of the housing opposite to the opening.

[0025] In the above technical solution, a first gap is provided between one end of the recess along its extension direction and the side of the housing with an opening to reserve assembly space between the end cap and the housing, thereby facilitating the assembly connection between the end cap and the housing. Furthermore, a second gap is provided between the other end of the recess along its extension direction and the side of the housing opposite to the opening, thereby facilitating the transition connection between the side of the housing opposite to the opening and the bottom wall surface of the receiving cavity.

[0026] In some embodiments of this application, the first gap is set in the range of 1.5mm-5mm; and / or, the second gap is set in the range of 2mm-5mm.

[0027] In the above technical solution, by setting the first gap in the range of 1.5mm-5mm, it is convenient for the end cap to extend into the housing and be welded to the housing.

[0028] By setting the second gap in the range of 2mm-5mm, it is possible to connect the side of the first wall facing away from the opening with the bottom surface of the shell using an arc transition, thereby reducing the risk of cracking due to stress concentration between the side of the first wall facing away from the opening and the bottom of the shell.

[0029] In some embodiments of this application, an insulating film is provided on the outer peripheral side of the electrode assembly, and the electrode assembly is insulated and isolated from the housing through the insulating film.

[0030] In the above technical solution, the electrode assembly is insulated from the housing through an insulating film, which reduces the risk of short circuit due to contact between the electrode assembly and the housing, and improves the stability of the battery cell.

[0031] In some embodiments of this application, the housing comprises an aluminum shell.

[0032] In the above technical solutions, the aluminum casing is relatively lightweight, which helps to meet the product's lightweight design requirements. Furthermore, the aluminum casing has a high thermal conductivity, which helps to improve the heat dissipation efficiency of the individual battery cells.

[0033] Secondly, this application provides a battery device comprising a plurality of battery cells as described in any one of the embodiments in the first aspect.

[0034] Thirdly, this application provides an energy storage device, comprising a plurality of battery cells as described in any one of the embodiments of the first aspect or at least one battery device as described in the embodiment of the second aspect, wherein the battery cells are used to store electrical energy or provide electrical energy.

[0035] Fourthly, this application provides an electrical device, including a battery device as described in the second aspect embodiment or an energy storage device as described in the third aspect embodiment. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0038] Figure 2 This is a schematic diagram of the structure of an energy storage device provided in some embodiments of this application;

[0039] Figure 3 Exploded views of battery devices provided in some embodiments of this application;

[0040] Figure 4 Exploded views of a single battery cell provided in some embodiments of this application;

[0041] Figure 5 A schematic diagram of the structure of a battery cell from one perspective, provided in some embodiments of this application;

[0042] Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure along the AA direction;

[0043] Figure 7 for Figure 6 Enlarged structural diagram of section C;

[0044] Figure 8 for Figure 5 Schematic diagram of the cross-sectional structure along the BB direction;

[0045] Figure 9 for Figure 8 Enlarged structural diagram of section D in the middle;

[0046] Figure 10 for Figure 8 Enlarged structural diagram of section E in the middle.

[0047] The attached figures are labeled as follows:

[0048] 1000, Vehicles; 2000, Energy storage devices;

[0049] 100. Battery unit; 200. Controller; 300. Motor; 400. Cabinet;

[0050] 10. Housing; 11. First housing; 12. Second housing; 20. Battery cell; 21. End cap; 211. Electrode terminal; 212. Pressure relief mechanism; 22. Housing; 221. First wall surface; 2211. Recess; 22111. First surface; 22112. Second surface; 2212. Heat dissipation channel; 222. Receiving cavity; 23. Electrode assembly; 231. Tab. Detailed Implementation

[0051] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0053] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0054] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0055] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0056] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0057] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0058] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0059] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of battery devices, the market demand is also constantly increasing.

[0060] In related technologies, battery devices include multiple battery cells, which are connected in series, parallel, or mixed connections. As the capacity requirements of battery devices increase, the size of the battery cell casings also increases, resulting in poor casing deformation resistance and insufficient mechanical strength. Consequently, the casings of battery cells are prone to deformation under cyclic charging and discharging or mechanical impact, and stress concentration easily occurs at the weld seams, affecting weld life and the operational stability of the battery cells.

[0061] To address the issues of poor deformation resistance and insufficient mechanical strength resulting from the increasing size of battery cell casings, this application designs a battery device. The battery device includes a housing and an electrode assembly. The housing includes a casing and an end cap, with a receiving cavity having an opening. The end cap seals the opening. The electrode assembly is housed within the receiving cavity through the opening. The housing has at least one recessed portion formed in a localized area towards the electrode assembly, with the wall surface of the recess being curved. By utilizing at least one recessed portion in the housing, the expansion force generated during the expansion of the electrode assembly is buffered. Furthermore, because the wall surface of the recess is curved, the stress can be evenly distributed to other areas of the housing, thereby improving the deformation resistance of the housing. This, in turn, helps reduce the stability of the connection between the housing and the end cap, and improves the reliability of the battery cell.

[0062] The technical solutions described in the embodiments of this application are applicable to battery cells, battery devices containing battery cells, energy storage devices using battery devices, and electrical equipment.

[0063] In this embodiment, the battery device 100 may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 20, which are connected in series, parallel, or mixed connections via busbars. In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 20. As an example, a battery cell assembly may be a battery module, which is formed by arranging and fixing multiple battery cells 20 into a single module. As an example, a battery module may be formed by bundling multiple battery cells 20 together with cable ties.

[0064] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 10 and one or more battery cell assemblies housed within the housing 10. As an example, the battery cell assembly may be a battery module, which can be housed within the housing 10 by securing the battery module to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells 20 to the housing 10. As an example, the housing 10 may include a first housing 11 and a second housing 12. The first housing 11 and the second housing 12 are fastened together to form a closed space inside the housing 10 for housing the battery cell assembly. Here, "closed" refers to covering or shutting down, and can be either sealed or unsealed. The first housing 11 may be a top cover or a bottom plate. As an example, the housing 10 may include a top cover, a frame, and a bottom plate. End caps and the bottom plate are connected to the frame, respectively, forming a closed space inside the housing 10 for housing the battery cell assembly. In some embodiments, the housing 10 may be part of the chassis structure of the vehicle 1000. For example, a portion of the box body 10 may be at least a part of the floor of the vehicle 1000, or a portion of the box body 10 may be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0065] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0066] Please refer to Figure 1 , Figure 1 The diagram illustrates the structure of a vehicle according to some embodiments of this application. The vehicle 1000 is equipped with a battery device 100, which may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0067] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0068] The energy storage device 2000 can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems, etc. The energy storage device 2000 can store electrical energy as needed and output it when appropriate. For example, the energy storage device 2000 can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires the energy storage device 2000.

[0069] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of an energy storage device provided in some embodiments of this application. The energy storage device 2000 is equipped with battery devices. In some embodiments, the energy storage device 2000 can be an energy storage container or an energy storage cabinet. In some embodiments, the energy storage device 2000 can include a cabinet 400 and one or more battery clusters, the battery clusters being housed in the cabinet 400, and the battery clusters may include multiple battery devices.

[0070] Please refer to Figure 3 , Figure 3 This is an exploded view of a battery device provided for some embodiments of this application. The battery device includes a battery cell 20 and a housing 10 for housing the battery cell 20. The housing 10 can have various structural forms.

[0071] In some embodiments, the housing 10 may include a first housing 11 and a second housing 12, which overlap each other, and together define a receiving space for accommodating the battery cell 20. A sealing element may also be provided at the connection point between the first housing 11 and the second housing 12 to achieve a sealed connection between them. For example, refer to... Figure 3 The first box 11 and the second box 12 can both be hollow structures with an opening on one side. The opening side of the first box 11 covers the opening side of the second box 12, thus forming a box 10 with a storage space. Alternatively, the second box 12 can be a hollow structure with an opening on one side, and the first box 11 can be a lid that covers the opening side of the second box 12. The box 10 can have various shapes, such as a cylindrical box 10, a cuboid box 10, etc.

[0072] In some embodiments of this application, the battery device can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0073] Please refer to Figure 4 , Figure 4This is an exploded view of a battery cell provided in some embodiments of this application. Embodiments of this application provide a battery cell 20, including a housing and an electrode assembly 23. The housing includes a casing 22 and an end cap 21. The casing 22 has a receiving cavity 222 with an opening. The electrode assembly 23 is housed within the receiving cavity 222, and the end cap 21 seals the opening. The casing 22 is partially recessed towards the electrode assembly 23, forming at least one recess 2211, the wall surface of which is curved.

[0074] In this embodiment, the battery cell 20 may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, magnesium-ion batteries, or solid-state batteries, etc., and this embodiment does not limit it.

[0075] As an example, in this embodiment of the application, the battery cell 20 is in the shape of a cuboid.

[0076] The battery cell 20 may include a casing, electrode components, and an electrolyte (which may be a solid electrolyte layer located between the positive and negative electrodes in a solid-state battery). The electrode components include at least one electrode assembly 23, which, along with the electrolyte, is housed within the casing component. The electrode assembly 23 includes a positive electrode, a negative electrode, and a separator (this structure may be omitted in solid-state batteries). The battery cell 20 primarily operates by the movement of metal ions between the positive and negative electrodes.

[0077] In the embodiments of this application, the electrode assembly 23 can be a wound or stacked structure. During processing, the positive electrode sheet, the negative electrode sheet, and the separator can be wound or stacked in sequence to obtain the electrode assembly 23.

[0078] In some embodiments, the electrode assembly 23 is provided with tabs 231, which can conduct current from the electrode assembly 23. The tabs 231 include a positive tab and a negative tab.

[0079] Specifically, the housing may include a housing 22 and an end cap 21. The housing 22 has a receiving cavity 222 with an opening. The end cap 21 forms a sealed cavity for accommodating electrode components and electrolyte by sealing the opening of the housing 22.

[0080] In some embodiments, the end cap 21 is provided with electrode terminals 211 and a pressure relief mechanism 212. The positive electrode terminal 211 is electrically connected to the tab 231 of the electrode assembly 23. The electrode terminal 211 includes a positive electrode terminal 211 and a negative electrode terminal 211. The pressure relief mechanism 212 is used to release internal gas from the battery cell 20.

[0081] As an example, the internal pressure or temperature of the battery cell 20 is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell 20 reaches the predetermined threshold, the pressure relief mechanism 212 is activated or a weak structure provided in the pressure relief mechanism 212 is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 20.

[0082] In this embodiment of the application, as an example, the recess 2211 can be a groove or cavity, and the wall surface of the recess 2211 is an arc-shaped curved surface.

[0083] By providing at least one recess 2211 on the housing 22, the recess 2211 is formed by a partial indentation from the outer surface of the housing 22 toward the electrode assembly 23, and by setting the wall surface of the recess 2211 as a curved surface, when the battery cell 20 is charging and discharging, the electrode assembly 23 expands and generates expansion force. The expansion force acts on the area where the recess 2211 is located, and the area where the recess 2211 is located can buffer the expansion force. It can also make the expansion force evenly transmitted to other areas of the housing 22 along the curved wall surface of the recess 2211. This can reduce the risk of overall deformation of the housing 22 and reduce the stress concentration coefficient of the connection area of ​​the housing 22, thereby reducing the risk of cracking in the connection area due to stress concentration and improving the stability of the battery cell 20 in use.

[0084] Please refer to Figure 4 and Figure 5 , Figure 5 This is a structural schematic diagram of a battery cell from one perspective, provided in some embodiments of this application. According to some embodiments of this application, the housing 22 has a first wall surface 221, which is the surface with the largest surface area in the housing 22. There are multiple recesses 2211, which are spaced apart circumferentially on the first wall surface 221 of the housing 22 and extend along the side of the housing 22 with an opening to the side away from the opening.

[0085] In this embodiment, it can be understood that there are two first wall surfaces 221, which are respectively provided on both sides of the thickness direction of the housing 22, and each first wall surface 221 is provided with a plurality of recesses 2211 at intervals.

[0086] Since the expansion force generated by the expansion of the electrode assembly 23 during the charging and discharging process of the battery cell 20 corresponds to the first wall surface 221 of the housing 22, by providing multiple recesses 2211 on the first wall surface 221 of the housing 22, and by providing multiple recesses 2211 at intervals along the circumference of the housing 22 and extending along the height direction of the housing 22, the expansion force generated by the electrode assembly 23 can be applied to the multiple recesses 2211 respectively. The multiple recesses 2211 buffer the expansion force generated by the electrode assembly 23 and disperse the expansion force to other areas of the housing 22, thereby improving the overall fatigue strength of the housing 22 and further reducing the risk of deformation of the housing 22 as a whole.

[0087] Please refer to Figure 5 , Figure 8 and Figure 9 , Figure 8 for Figure 5 Schematic diagram of the cross-sectional structure along the BB direction; Figure 9 for Figure 8 Enlarged structural schematic diagram of section D. According to some embodiments of this application, each recess 2211 has a first surface 22111 facing the electrode assembly 23, the first surface 22111 protruding into the receiving cavity and contacting the electrode assembly 23.

[0088] Understandably, the two first walls 221 of the housing 22 are arranged opposite to each other, and the first surfaces 22111 of the multiple recesses 2211 on the two first walls 221 respectively contact the two large surfaces of the electrode assembly 23.

[0089] When the electrode assembly 23 is installed in the receiving cavity 222 of the housing 22, it directly contacts the first surfaces 22111 of the multiple recesses 2211 on the two first wall surfaces 221. This allows the multiple recesses 2211 to fix the electrode assembly 23, reducing the risk of the electrode assembly 23 shaking in the housing 22 and improving the stability and reliability of the electrode assembly 23 installation. In addition, the direct contact between the electrode assembly 23 and the multiple recesses 2211 can also shorten the heat conduction path between the electrode assembly 23 and the housing 22, which helps to improve the overall temperature regulation efficiency of the battery cell 20.

[0090] Please refer to Figure 10 , Figure 10 for Figure 8 An enlarged structural diagram of section E. According to some embodiments of this application, a heat dissipation channel 2212 is formed between two adjacent recesses 2211 and the electrode assembly 23.

[0091] During the charging and discharging process, the battery cell 20 generates gas. The gas can flow in an orderly manner towards the end cover 21 through the heat dissipation channel 2212 formed between the two adjacent recesses 2211 and the electrode assembly 23. This not only reduces the local pressure rise caused by the accumulation of gas in the local area of ​​the housing 22, but also provides a pre-flow path for the opening of the pressure relief mechanism 212 on the end cover 21, thereby further improving the stability of the battery cell 20 in use.

[0092] Please refer to Figures 4 to 7 , Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure along the AA direction; Figure 7 for Figure 6 An enlarged structural schematic diagram of section C. According to some embodiments of this application, the area between two adjacent recesses 2211 in the first wall surface 221 is a plane, and the edges of the recesses 2211 are connected to the plane by a rounded transition.

[0093] In this embodiment of the application, the recess 2211 is generally elongated, and the four edges of the recess 2211 are connected to the plane by arc transitions.

[0094] By using a rounded transition between the edge of the recess 2211 and the plane, the risk of excessive deformation or cracking at the connection between the edge of the recess 2211 and the plane due to stress concentration can be reduced.

[0095] According to some embodiments of this application, the wall thickness L1 of the region where the corresponding recess 2211 is located in the housing 22 is the same as the wall thickness L2 of the region where the corresponding plane is located.

[0096] The recess 2211 can be integrally formed by stamping. The wall thickness L1 of the area where the recess 2211 is located in the shell 22 is consistent with the wall thickness L2 of the area where the plane of the shell 22 is located. This can improve the material utilization rate when processing the shell 22. Compared with the solution of thinning the wall thickness of the area where the recess 2211 is located, it helps to improve the rigidity and fatigue strength of the area where the recess 2211 is located.

[0097] According to some embodiments of this application, the recess 2211 also has a second surface 22112, which is the side surface of the recess 2211 facing away from the electrode assembly 23, and the second surface 22112 is arranged parallel to the first surface 22111.

[0098] In this embodiment, the thickness of the first surface 22111 and the second surface 22112 is uniformly set at all locations.

[0099] Understandably, the recess 2211 is a three-dimensional curved surface structure, which is not only easy to process and shape, but also easy to use the recess 2211 to buffer the expansion force generated when the electrode assembly 23 expands.

[0100] According to some embodiments of this application, the radius of curvature of the first surface 22111 is set in the range of 90mm-100mm.

[0101] It is understandable that the second surface 22112 and the first surface 22111 have the same radius of curvature.

[0102] The radius of curvature is mainly used to describe the degree of curvature of a curve at a certain point. Since the wall of the recess 2211 is curved, it can be understood that when looking from one side of the shell 22 with an opening to the other side, the shape of the recess 2211 is a curve. The curve is differentiated as much as possible until it finally approximates an arc. The radius corresponding to this arc is the radius of curvature of this point on the curve.

[0103] By setting the radius of curvature of the first surface 22111 in the range of 90mm-100mm, it is not only easier to process and shape, but also makes the surface of the recess 2211 relatively flat, which helps to improve the uniformity of stress dispersion by utilizing the surface of the recess 2211.

[0104] According to some embodiments of this application, the center distance between two adjacent recesses 2211 is set in the range of 40mm-50mm.

[0105] Since the concave part 2211 is a curved surface, the center distance between two adjacent concave parts 2211 is the distance between the centers of two adjacent curved surfaces.

[0106] By setting the center distance between two adjacent recesses 2211 in the range of 40mm-50mm, the heat dissipation channel 2212 formed by the two adjacent recesses 2211 and the electrode assembly 23 is relatively large, so that the gas in the housing 22 can be quickly discharged to the side of the end cap 21 along the heat dissipation channel 2212. This also helps to further improve the fatigue strength of the housing 22, so as to further reduce the risk of deformation of the housing 22 due to stress concentration.

[0107] According to some embodiments of this application, along the extending direction of the recess 2211, a first gap is provided between one end of the recess 2211 and the side of the housing 22 with an opening, and a second gap is provided between the other end of the recess 2211 and the side of the housing 22 away from the opening.

[0108] By providing a first gap between one end of the recess 2211 along its extending direction and the side of the housing 22 with an opening, assembly space is reserved between the end cap 21 and the housing 22, thereby facilitating the assembly connection between the end cap 21 and the housing 22. Furthermore, by providing a second gap between the other end of the recess 2211 along its extending direction and the side of the housing 22 opposite to the opening, a transition connection is facilitated between the side of the housing 22 opposite to the opening and the bottom wall surface of the receiving cavity.

[0109] According to some embodiments of this application, the first gap is set in the range of 1.5mm-5mm; the second gap is set in the range of 2mm-5mm.

[0110] By setting the distance between the side of the housing 22 with the opening and the recess 2211 in the range of 1.5mm-5mm, it is easy for the end cap 21 to extend into the housing 22 and be welded to the housing 22.

[0111] By setting the distance between the side of the housing 22 away from the opening and the recess 2211 within the range of 2mm-5mm, it is possible to facilitate the connection between the side of the first wall surface 221 away from the opening and the bottom surface of the housing 22 by means of an arc transition, so as to reduce the risk of cracking due to stress concentration between the side of the first wall surface 221 away from the opening and the bottom of the housing 22.

[0112] According to some embodiments of this application, an insulating film is provided on the outer periphery of the electrode assembly 23, and the electrode assembly 23 is insulated and isolated from the housing 22 through the insulating film.

[0113] The electrode assembly 23 is insulated from the housing 22 by an insulating film, which reduces the risk of short circuit due to contact between the electrode assembly 23 and the housing 22 and improves the stability of the battery cell 20.

[0114] According to some embodiments of this application, housing 22 includes an aluminum shell.

[0115] The aluminum casing is lightweight, which helps meet the product's lightweight design requirements. Furthermore, the aluminum casing has a high thermal conductivity, which helps improve the heat dissipation efficiency of the individual battery cells.

[0116] In some embodiments of this application, a sacrificial anode coating is provided on the surface of the housing 22 facing away from the electrode assembly 23. The sacrificial anode coating can form an galvanic corrosion with the housing 22, and the sacrificial anode coating is preferentially corroded to improve the service life of the housing 22.

[0117] According to some embodiments of this application, see Figures 4 to 10This application provides a battery cell 20, including a housing and an electrode assembly 23. The housing includes a casing and an end cap. The casing 22 has a receiving cavity 222 with an opening, and the end cap 21 seals the opening. The electrode assembly 23 is housed within the receiving cavity 222. The casing 22 has two first walls 221, which are the surfaces with the largest surface area in the casing 22. These two first walls 221 are located on opposite sides of the casing 22 in the thickness direction. Along the circumference of the casing 22, each first wall 221 has a plurality of recesses 2211 spaced apart. Each recess 2211 extends from the side of the casing 22 with the opening to the other side, and the wall surface of each recess 2211 is an arc-shaped curved surface. Each recess 2211 has a first surface 22111 protruding towards the electrode assembly 23. The first surface 22111 is an arc-shaped curved surface. The first surfaces 22111 of the multiple recesses 2211 provided on each first wall 221 are all in contact with the electrode assembly 23, and a heat dissipation channel 2212 is formed between adjacent recesses 2211 and the electrode assembly 23. Through the technical solution of this application, the bending strength and deformation resistance of the first wall 221 of the housing 22 can be improved, and the risk of cracking due to stress concentration in the connection area of ​​the housing 22 can be reduced, thereby improving the stability of the battery cell 20 in use.

[0118] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The housing includes a shell and an end cap, the shell having a receiving cavity with an opening, and the end cap sealing the opening; The electrode assembly is housed within the receiving cavity; The housing has at least one recessed portion formed in a direction close to the electrode assembly, and the wall surface of the recessed portion is curved.

2. The battery cell according to claim 1, characterized in that, The housing has a first wall surface, which is the surface with the largest surface area in the housing. There are multiple recesses, which are spaced apart on the first wall surface along the circumference of the housing and extend from one side of the housing with the opening to the other side.

3. The battery cell according to claim 2, characterized in that, Each of the recesses has a first surface facing the electrode assembly, the first surface protruding into the receiving cavity and contacting the electrode assembly.

4. The battery cell according to claim 2, characterized in that, A heat dissipation channel is formed between two adjacent recesses and the electrode assembly.

5. The battery cell according to any one of claims 2-4, characterized in that, The area between two adjacent recesses in the first wall surface is a plane, and the edge of the recess is connected to the plane by a rounded transition.

6. The battery cell according to claim 5, characterized in that, The wall thickness of the region corresponding to the recess in the housing is the same as the wall thickness of the region corresponding to the plane.

7. The battery cell according to claim 3, characterized in that, The recess also has a second surface, which is the side of the recess facing away from the electrode assembly, and the second surface is arranged parallel to the first surface.

8. The battery cell according to claim 3, characterized in that, The radius of curvature of the first surface is set in the range of 90mm-100mm.

9. The battery cell according to any one of claims 2-4, characterized in that, The center distance between two adjacent recesses is set in the range of 40mm-50mm.

10. The battery cell according to any one of claims 1-4, characterized in that, Along the extending direction of the recess, a first gap is provided between one end of the recess and the side of the housing with the opening, and a second gap is provided between the other end of the recess and the side of the housing opposite to the opening.

11. The battery cell according to claim 10, characterized in that, The first gap is set within the range of 1.5mm-5mm; And / or, the second gap distance is set in the range of 2mm-5mm.

12. The battery cell according to any one of claims 1-4, characterized in that, An insulating film is provided on the outer periphery of the electrode assembly, and the electrode assembly is insulated and isolated from the housing through the insulating film.

13. The battery cell according to any one of claims 1-4, characterized in that, The housing includes an aluminum shell.

14. A battery device, characterized in that, It includes multiple battery cells as described in any one of claims 1-13.

15. An energy storage device, characterized in that, It includes a plurality of battery cells as described in any one of claims 1-13 or at least one battery device as described in claim 14, wherein the battery cells are used to store electrical energy or provide electrical energy.

16. An electrical appliance, characterized in that, This includes the battery device as described in claim 14 or the energy storage device as described in claim 15.

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