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

Abstract

A battery cell (10), a battery (100), an energy storage device (2000), and an electric device. The battery cell (10) comprises a casing (11). An opening (11a) is formed in an end portion of the casing (11) in a first direction. In the circumferential direction of the opening (11a), the casing (11) comprises first walls (110), corner areas (112), and second walls (113) which are connected in sequence. Each first wall (110) is provided with a first body portion (1100) and a first thickening portion (1101) which are arranged in the first direction, the first body portion (1100) is farther from the opening (11a) than the first thickening portion (1101), and the maximum thickness of the first thickening portion (1101) is greater than that of the first body portion (1100). Each corner area (112) is provided with a second body portion (1120) and a second thickening portion (1121) which are arranged in the first direction, the second body portion (1120) is farther from the opening (11a) than the second thickening portion (1121), and the maximum thickness of the second thickening portion (1121) is greater than that of the second body portion (1120). The provided technical solution can improve the reliability of the battery cell (10).

Description

Battery cells, batteries, energy storage devices and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to PCT patent application PCT / CN2023 / 134129, entitled “Casing, battery cell, battery and electrical device” filed on November 24, 2023, and priority to Chinese patent application 202323280449.1, entitled “Battery cell, battery, energy storage device and electrical device” filed on November 30, 2023. The entire contents of the above applications are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, an energy storage device, and an electrical device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] In the development of battery technology, how to improve battery reliability is a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery, an energy storage device and an electrical device. The technical solution provided in the present application can improve the reliability of the battery cell.

[0008] This application is achieved through the following technical solutions:

[0009] In a first aspect, some embodiments of the present application provide a battery cell. The battery cell includes a shell. An opening is formed at an end of the shell along a first direction. Along the circumference of the opening, the shell includes a first wall, a corner area, and a second wall connected in sequence. The first wall has a first main body portion and a first thickened portion arranged along the first direction, the first main body portion is farther away from the opening than the first thickened portion, and the maximum thickness of the first thickened portion is greater than the thickness of the first main body portion. The corner area has a second main body portion and a second thickened portion arranged along the first direction, the second main body portion is farther away from the opening than the second thickened portion, and the maximum thickness of the second thickened portion is greater than the thickness of the second main body portion.

[0010] In the above solution, by providing the first thickened portion on the first wall, the problem of a heat-affected zone with low strength formed by welding in the shell, which can cause the first wall to crack due to insufficient strength when impacted, can be alleviated, thus improving the reliability of the battery. At the same time, by providing the second thickened portion in the corner area, the strength of the corner area corresponding to the opening can be improved, improving the problem of stress concentration during shell manufacturing caused by the first thickened portion (for example, during shell stretch forming, the stress generated during demolding will concentrate on the corner area corresponding to the opening), which can cause cracking in the corner area, thereby improving the reliability of the battery cell.

[0011] According to some embodiments of the present application, the maximum thickness of the second thickened portion is greater than the maximum thickness of the first thickened portion.

[0012] In the above solution, by setting the maximum thickness of the second thickened portion to be greater than the maximum thickness of the first thickened portion, the strength of the portion of the corner area corresponding to the opening can be effectively improved. On the one hand, the overall thickness of the shell can be effectively increased, and the risk of the shell cracking due to impact can be reduced. On the other hand, the stress concentration during the shell manufacturing process can be effectively improved, which causes the problem of cracking in the corner area, thereby making the battery cell have higher reliability.

[0013] According to some embodiments of the present application, the maximum thickness of the second thickened portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the first thickened portion is t1, and the thickness of the first main body portion is t2, satisfying E≥F, E=(T1-T2) / T2, F=(t1-t2) / t2.

[0014] In the above scheme, by limiting the degree of thickening E of the second thickened portion compared to the second main body portion to no less than the degree of thickening F of the first thickened portion compared to the first main body portion, the problem of stress concentration during the shell manufacturing process caused by the provision of the first thickened portion, resulting in cracking in the corner area, can be effectively improved, thereby making the battery cell have higher reliability.

[0015] According to some embodiments of the present application, the maximum thickness of the second thickened portion is T1, and the thickness of the second main body portion is T2, satisfying 0<E<30%, E=(T1-T2) / T2.

[0016] In the above scheme, by limiting the degree E of thickening of the second thickened portion compared to the second main body portion, on the one hand, the strength of the corner area can be improved and the risk of cracking in the corner area due to stress concentration can be reduced; on the other hand, the risk of bulging of the corner area and deformation of the outer shell due to excessive stress can be reduced, so that the battery cell has higher reliability.

[0017] According to some embodiments of the present application, 0<E≤16.7% is satisfied.

[0018] In the above scheme, by limiting the degree of thickening E of the second thickened portion relative to the second main body portion to no more than 16.7%, on the one hand, it can take into account the improvement of the problems of cracking caused by stress concentration and deformation caused by excessive stress; on the other hand, it can effectively control the weight of the shell, which is conducive to the improvement of the weight energy density of the battery cell.

[0019] According to some embodiments of the present application, along the first direction, a distance from one end of the second thickened portion away from the opening to the opening is L1, satisfying 0<L1≤20mm.

[0020] In the above scheme, along the first direction, by providing a second thickened portion in the corner area within 20 mm below the opening, the strength of the portion of the corner area corresponding to the opening can be effectively improved, and the risk of cracking in the corner area due to stress concentration in the portion of the corner area corresponding to the opening during the shell manufacturing process caused by thickening the first wall is reduced, so that the battery cell has higher reliability.

[0021] According to some embodiments of the present application, along the first direction, a distance from one end of the first thickened portion away from the opening to the opening is L2, satisfying 0<L2≤20mm.

[0022] In the above scheme, along the first direction, by providing a first thickened portion in the area of ​​the first wall within 20 mm below the opening, the strength of the portion of the first wall corresponding to the opening can be effectively improved, and the risk of the first wall being easily cracked by impact due to the low-strength heat-affected zone generated by the welding of the shell at the portion corresponding to the opening is reduced, thereby making the battery cell have higher reliability.

[0023] According to some embodiments of the present application, an area of ​​an outer surface of the first wall is greater than an area of ​​an outer surface of the second wall.

[0024] In the above solution, by providing the first thickened portion on the first wall with a larger outer surface area, the risk of the shell being easily cracked by impact can be effectively improved, so that the battery cell has higher reliability.

[0025] According to some embodiments of the present application, the housing includes two first walls disposed opposite each other along the second direction, and two second walls disposed opposite each other along the third direction, with the second direction, the third direction, and the first direction being perpendicular to each other. Adjacent first and second walls are connected by corresponding corner regions, and the first walls, the second walls, and the corner regions collectively form an opening.

[0026] In the above solution, the housing can be a square structure. By thickening two walls arranged opposite each other along the second direction, i.e., providing a first thickened portion, the structural strength of the housing can be effectively improved, reducing the risk of cracking due to impact. Furthermore, by thickening the corner area between the two adjacent walls, i.e., providing a second thickened portion, the problem of cracking in the corner area due to stress concentration can be alleviated, thereby ensuring higher reliability of the battery cell.

[0027] According to some embodiments of the present application, the second wall has a third main body portion and a third thickened portion arranged along the first direction, the third main body portion is farther away from the opening than the third thickened portion, and the maximum thickness of the third thickened portion is greater than the thickness of the third main body portion.

[0028] In the above solution, by providing a third thickened portion with a larger maximum thickness on the second wall, the risk of a heat-affected zone with lower strength formed in the shell due to welding, which causes the second wall to crack due to insufficient strength when impacted, can be improved, thereby making the battery cell more reliable.

[0029] According to some embodiments of the present application, the maximum thickness of the second thickened portion is greater than the maximum thickness of the third thickened portion.

[0030] In the above solution, by setting the maximum thickness of the second thickened portion to be greater than the maximum thickness of the third thickened portion, the strength of the portion of the corner area corresponding to the opening can be effectively improved. On the one hand, the overall thickness of the shell can be effectively increased, and the risk of the shell cracking due to impact can be reduced. On the other hand, the problem of stress concentration in the corner area during the shell manufacturing process, which leads to cracking in the corner area, can be effectively improved, so that the battery cell has higher reliability.

[0031] According to some embodiments of the present application, the maximum thickness of the second thickened portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the third thickened portion is t3, and the thickness of the third main body portion is t4, satisfying E≥G, E=(T1-T2) / T2, G=(t3-t4) / t4.

[0032] In the above scheme, by limiting the degree of thickening E of the second thickened portion compared to the second main body portion to no less than the degree of thickening G of the third thickened portion compared to the third main body portion, the problem of stress concentration at the corner portion corresponding to the opening during the shell manufacturing process due to the provision of the third thickened portion, resulting in cracking of the corner area, can be effectively improved, thereby making the battery cell have higher reliability.

[0033] According to some embodiments of the present application, along the first direction, a distance from one end of the third thickened portion away from the opening to the opening is L3, satisfying 0<L3≤20mm.

[0034] In the above solution, along the first direction, by providing a third thickened portion in the area of ​​the second wall within 20 mm below the opening, the strength of the portion of the second wall corresponding to the opening can be effectively improved, and the risk of the second wall being easily cracked by impact can be reduced, so that the battery cell has higher reliability.

[0035] According to some embodiments of the present application, the battery cell further includes an end cap that seals the opening. The third thickened portion includes a first segment and a second segment that are interconnected, the first segment, the second segment, and the third body portion being sequentially arranged along a first direction, the maximum thickness of the second segment being greater than the thickness of the third body portion, the maximum thickness of the second segment being greater than the maximum thickness of the first segment, and the end cap being connected to the first segment.

[0036] In the above solution, by setting the thickness of the second section of the third thickened portion to be greater than the thickness of the third main body portion, the strength of the second wall can be effectively improved, and the risk of the second wall cracking due to impact can be reduced, so that the battery cell has higher reliability.

[0037] According to some embodiments of the present application, a first step surface is formed between the second section and the first section, and the end cover overlaps the first step surface.

[0038] In the above solution, the first step surface formed between the second section and the first section can enable the end cover to overlap the first step surface, thereby facilitating the positioning and assembly of the end cover. At the same time, the first step surface can support the end cover, which can reduce the risk of the end cover collapsing, thereby making the battery cell have higher reliability.

[0039] According to some embodiments of the present application, the battery cell also includes an end cover, which closes the opening; the second thickened portion includes a third segment and a fourth segment that are connected to each other, and the third segment, the fourth segment and the second main body are distributed in sequence along the first direction, the maximum thickness of the fourth segment is greater than the thickness of the second main body, the maximum thickness of the fourth segment is greater than the maximum thickness of the third segment, and the end cover is connected to the third segment.

[0040] In the above solution, by setting the thickness of the fourth section of the second thickened portion to be greater than the thickness of the second main body portion, the strength of the corner area can be effectively improved, and the risk of the corner area being impacted or cracked due to stress concentration during demolding can be reduced, so that the battery cell has higher reliability.

[0041] According to some embodiments of the present application, a second step surface is formed between the fourth section and the third section, and the end cover overlaps the second step surface.

[0042] In the above scheme, the second step surface formed between the fourth section and the third section can enable the end cover to overlap the second step surface, thereby facilitating the positioning and assembly of the end cover; at the same time, the second step surface plays a supporting role for the end cover, which can reduce the risk of the end cover collapsing, thereby making the battery cell have higher reliability.

[0043] According to some embodiments of the present application, the battery cell also includes an end cover, which is welded to the second thickened portion to form a fusion zone. The average grain size of the second thickened portion other than the fusion zone is larger than the average grain size of the second main body portion, and the average grain size is the average grain size of the grains in the first direction.

[0044] In the above scheme, by limiting the average grain size of the second thickened portion other than the welding zone to be larger than the average grain size of the second main body, it is beneficial to enhance the strength of the corner zone, so that the second thickened portion has higher strength, reduces the risk of the corner zone cracking near the welding zone due to impact and the risk of the corner zone cracking due to stress concentration during demolding, and makes the battery cell have higher reliability.

[0045] According to some embodiments of the present application, on a cross-section of the corner region parallel to the first direction, in a portion of the second thickened portion below the fusion zone, the number of grains in the width direction of the cross-section is greater than or equal to 15.

[0046] In the above solution, in the width direction of the cross section, the number of grains is greater than or equal to, which is beneficial to enhancing the strength of the second thickened portion, reducing the risk of shell cracking, and improving the reliability of the battery cell.

[0047] According to some embodiments of the present application, the average grain size of the second thickened portion excluding the fusion zone is in the range of 70 μm to 1200 μm; and / or, the average grain size of the second main body portion is in the range of 30 μm to 1000 μm; and / or, the maximum wall thickness of the end cover is in the range of 0.25 mm to 3 mm.

[0048] In the above solution, the average grain size of the second thickened portion and / or the average grain size of the second main body portion satisfy the above relationship, which is beneficial to enhancing the strength of the second thickened portion and making the battery cell have higher reliability.

[0049] In a second aspect, the present application further provides a battery comprising the battery cell of the first aspect.

[0050] In a third aspect, the present application further provides an energy storage device comprising the battery cell of the first aspect.

[0051] In a fourth aspect, the present application further provides an electrical device comprising the battery cell of the first aspect, for providing electrical energy.

[0052] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0054] FIG1 is a schematic diagram of a vehicle in some embodiments of the present application;

[0055] FIG2 is a schematic diagram of an energy storage device in some embodiments of the present application;

[0056] FIG3 is a perspective exploded view of a battery in some embodiments of the present application;

[0057] FIG4 is a perspective exploded view of a partial structure of a battery cell in some embodiments of the present application;

[0058] FIG5 is a front view of a battery cell in some embodiments of the present application;

[0059] FIG6 is a cross-sectional view taken along line AA in FIG5 ;

[0060] FIG7 is an enlarged view of point B in FIG6;

[0061] FIG8 is a cross-sectional view taken along the CC line in FIG5 ;

[0062] FIG9 is an enlarged view of point D in FIG8 ;

[0063] FIG10 is a schematic diagram of the internal structure of a battery cell in some embodiments of the present application;

[0064] FIG11 is an enlarged view of point H in FIG10 ;

[0065] FIG12 is an enlarged view of point L in FIG4 ;

[0066] FIG. 13 is a schematic diagram of end caps and corner areas in some embodiments of the present application.

[0067] Icon: 100-battery; 10-battery cell; 11-housing; 12-electrode assembly; 13-electrode terminal; 11a-opening; 14-end cap; 110-first wall; 1100-first body; 1101-first thickened portion; 112-corner area; 1120-second body; 1121-second thickened portion; 1121a-third section; 1121b-fourth section; 1121c-second step surface; 113-first Second wall; 1130-third main body; 1131-third thickened portion; 1131a-first section; 1131b-second section; 1131c-first step surface; 114-welding area; 20-box; 21-first box part; 22-second box part; z-first direction; x-second direction; y-third direction; 1000-vehicle; 200-controller; 300-motor; 2000-energy storage device; 2001-cabinet. DETAILED DESCRIPTION

[0068] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0070] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0071] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0072] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0073] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0074] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0075] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0076] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., which are not limited in the embodiments of the present application. Battery cells may be rectangular or in other shapes, etc., which are not limited in the embodiments of the present application. The battery mentioned in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery generally includes a casing for encapsulating one or more battery cells. The casing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0077] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement (e.g., deintercalation) of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive current collector uncoated with the positive active material layer protrudes from the positive current collector coated with the positive active material layer, and the positive current collector uncoated with the positive active material layer serves as the positive tab. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector uncoated with the negative active material layer protrudes from the negative current collector coated with the negative active material layer, and the negative current collector uncoated with the negative active material layer serves as the negative tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass through without melting, the number of positive electrode ears is multiple and stacked together, and the number of negative electrode ears is multiple and stacked together. The material of the isolation membrane may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, and the embodiments of the present application are not limited to this. The battery cell also includes a shell and an end cover, and the electrode assembly and the electrolyte are arranged in the shell. Along the first direction, the shell is formed with an opening, and the end cover is welded to the shell to close the opening of the shell. In some embodiments, along the circumference of the opening, the shell includes a first wall, a corner area and a second wall connected in sequence, the first wall and the second wall are adjacent, and the first wall and the second wall are transitionally connected through the corner area.

[0078] The development of battery technology must consider many design factors at the same time, such as performance parameters such as energy density, cycle life, discharge capacity, charge and discharge rate, and the reliability of the battery must also be considered. For battery cells, after the end caps are welded to the shell, a heat-affected zone is often formed below the molten pool, which reduces the strength of the shell. This causes the shell to crack when the battery cell is impacted or expands internally, resulting in battery failure. To improve this problem, the walls of the battery shell are currently thickened or partially thickened, such as by thickening the portion of the first wall of the shell corresponding to the opening to increase the strength of the shell. However, this type of shell is made using a stretch forming process. When the shell is elastically demolded, the stress will be concentrated in the corner area corresponding to the opening, which can easily cause cracking in the corner area, affecting the reliability of the battery cell, and thus affecting the reliability of the battery.

[0079] In view of this, in order to improve the problem that the shell cracks in the corner area due to stress concentration during elastic demolding, which affects the reliability of the battery cell, some embodiments of the present application provide a battery cell, which includes a shell. The shell is formed with an opening at the end along the first direction. Along the circumference of the opening, the shell includes a first wall, a corner area and a second wall connected in sequence. The first wall has a first main body portion and a first thickened portion arranged along the first direction, the first main body portion is farther away from the opening than the first thickened portion, and the maximum thickness of the first thickened portion is greater than the thickness of the first main body portion. Among them, the corner area has a second main body portion and a second thickened portion arranged along the first direction, the second main body portion is farther away from the opening than the second thickened portion, and the maximum thickness of the second thickened portion is greater than the thickness of the second main body portion.

[0080] In the above solution, by providing a first thickened portion with a greater maximum thickness on the first wall, the risk of cracking the first wall due to insufficient strength during impact, caused by the formation of a heat-affected zone with lower strength due to welding, can be mitigated, thus improving the reliability of the battery. Furthermore, by providing a second thickened portion with a greater maximum thickness in the corner area, the strength of the corner area corresponding to the opening can be improved, thereby alleviating the problem of stress concentration during elastic demolding caused by the first thickened portion, which can lead to cracking in the corner area, thus improving the reliability of the battery cell.

[0081] The technical solutions described in the embodiments of the present application are applicable to batteries, energy storage devices having battery modules, and electrical devices using battery modules.

[0082] The energy storage device may include multiple battery cells, which may be connected in series, in parallel, or in hybrid. The energy storage device may be a device capable of storing electrical energy, such as an energy storage cabinet or an energy storage box.

[0083] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include new energy vehicles, which may include pure electric vehicles, hybrid electric vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0084] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle 1000 as an example.

[0085] FIG1 is a schematic diagram of a vehicle 1000 in some embodiments of the present application.

[0086] A controller 200, a motor 300, and a battery 100 may be provided inside the vehicle 1000. The controller 200 is used to control the battery 100 to power the motor 300. For example, the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000 and for the circuit system of the vehicle 1000, for example, for the starting, navigation, and operating power requirements of the vehicle 1000. In another embodiment of the present application, the battery 100 may serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0087] Figure 2 is a schematic diagram of an energy storage device in some embodiments of the present application. Energy storage device 2000 can be a device for storing electrical energy. For example, energy storage device 2000 can include an energy storage cabinet, which includes a cabinet body 2001 and one or more batteries 100 disposed within the cabinet body. Cabinet body 2001 can include a cabinet body and a cabinet door. One or more batteries 100 are disposed within the cabinet body. The cabinet door seals an opening in the cabinet body, enclosing the one or more batteries 100 in a closed space and reducing the impact of external substances on the batteries 100.

[0088] Please refer to FIG3 , which is a three-dimensional exploded view of the battery 100 in some embodiments of the present application.

[0089] The battery 100 includes a battery cell 10 and a housing 20, with the battery cell 10 housed within the housing 20. The housing 20 is used to provide a storage space for the battery cell 10 and can have various structures. In some embodiments, the housing 20 can include a first housing portion 21 and a second housing portion 22, which overlap with each other and together define a storage space for the battery cell 10. The second housing portion 22 can be a hollow structure with an opening 11a at one end. The first housing portion 21 can be a plate-like structure, with the first housing portion 21 overlapping the opening 11a of the second housing portion 22, so that the first housing portion 21 and the second housing portion 22 jointly define a storage space. Alternatively, the first housing portion 21 and the second housing portion 22 can each be a hollow structure with an opening 11a at one end, with the opening 11a of the first housing portion 21 overlapping the opening 11a of the second housing portion 22. Of course, the box body 20 formed by the first box body portion 21 and the second box body portion 22 can be in various shapes, such as a cylinder, a cuboid, etc.

[0090] In the battery 100 , there may be one or more battery cells 10 , and each battery cell 10 may be fixed to the case 20 via a connector (such as a bolt), or each battery cell 10 may be fixed to the case 20 by bonding.

[0091] Some embodiments of the present application provide a battery cell 10, please refer to Figures 4 to 11, Figure 4 is a three-dimensional exploded view of the local structure of the battery cell 10 in some embodiments of the present application, Figure 5 is a main view of the battery cell 10 in some embodiments of the present application, Figure 6 is a sectional view taken along the AA direction in Figure 5, Figure 7 is an enlarged view of point B in Figure 6, Figure 8 is a sectional view taken along the CC direction in Figure 5, Figure 9 is an enlarged view of point D in Figure 8, Figure 10 is a schematic diagram of the internal structure of the battery cell 10 in some embodiments of the present application, and Figure 11 is an enlarged view of point H in Figure 10.

[0092] The battery cell 10 includes a housing 11. An opening 11a is formed at an end of the housing 11 along a first direction z. Along the circumference of the opening 11a, the housing 11 includes a first wall 110, a corner region 112, and a second wall 113 connected in sequence. The first wall 110 has a first main body portion 1100 and a first thickened portion 1101 arranged along the first direction z. The first main body portion 1100 is farther away from the opening 11a than the first thickened portion 1101, and the maximum thickness of the first thickened portion 1101 is greater than the thickness of the first main body portion 1100. The corner region 112 has a second main body portion 1120 and a second thickened portion 1121 arranged along the first direction z. The second main body portion 1120 is farther away from the opening 11a than the second thickened portion 1121, and the maximum thickness of the second thickened portion 1121 is greater than the thickness of the second main body portion 1120.

[0093] In some embodiments, the battery cell 10 may include a housing 11 and an end cap 14. Along a first direction z, the housing 11 has an opening 11a. The electrode assembly 12 is disposed inside the housing 11. The end cap 14 is connected to the housing 11 to close the opening 11a, so that the electrode assembly 12 is located in a closed space. In some embodiments, the end cap 14 may be provided with an electrode terminal 13, which is connected to the tab of the electrode assembly 12 to enable current output and input. In some embodiments, the end cap 14 may be provided with an injection hole, through which the electrolyte can be injected into the housing 11. In some embodiments, the end cap 14 may be riveted, welded, or screwed to the housing 11.

[0094] In some embodiments, along the circumference of the opening 11a of the housing 11, the housing 11 may include multiple interconnected wall portions. For example, along the circumference of the opening 11a, the housing 11 includes a first wall 110, a corner region 112, and a second wall 113, which are sequentially connected. The first wall 110 and the second wall 113 are disposed adjacent to each other, and the first wall 110 and the second wall 113 are transitionally connected via the corner region 112. For example, when the housing 11 is square or quasi-square, along the second direction x, the housing 11 has two first walls 110 disposed opposite each other, and along the third direction y, the housing 11 has two second walls 113 disposed opposite each other. The second direction x and the third direction y are perpendicular to each other. Adjacent first walls 110 and second walls 113 are connected via corresponding corner regions 112. The first walls 110, second walls 113, and the corner regions 112 collectively enclose the opening 11a. In some embodiments, the cross-section of the corner regions 112 may be arc-shaped, so that the first wall 110 and the second wall 113 transition into a circular arc. In other embodiments, the cross-section of the corner area 112 may not be arc-shaped, but may be polygonal, so as to achieve a smooth transition between the first wall 110 and the second wall 113 .

[0095] In some embodiments, the first direction z may be parallel to the height direction of the battery cell 10 , the second direction x may be the thickness direction of the battery cell 10 , and the third direction y may be the width direction of the battery cell 10 .

[0096] In some embodiments, the area of ​​the outer surface of the first wall 110 may be greater than the area of ​​the outer surface of the second wall 113. In other embodiments, the area of ​​the outer surface of the first wall 110 may be less than the area of ​​the outer surface of the second wall 113. In other embodiments, the area of ​​the outer surface of the first wall 110 may be equal to the area of ​​the outer surface of the second wall 113.

[0097] In some embodiments, the shell 11 can be made by a process such as a stretching forming process. The stretching forming process may include a stretching process and a demolding process. Generally, the stretching process refers to: in the stretching station, stress is applied to the metal sheet to cause it to deform. During the stretching process, parameters such as stress magnitude, speed and time need to be controlled to avoid problems such as breakage or uneven stress of the metal sheet. Hydraulic or mechanical drive is usually used to apply the stretching force. Generally, the demolding process is also called elastic demolding, which may refer to: after the stretching is completed, the finished product is slid out of the mold. Pneumatic demolding or mechanical demolding is usually used.

[0098] “The first wall 110 has a first main body portion 1100 and a first thickened portion 1101 arranged along the first direction z, and the first main body portion 1100 is farther away from the opening 11a than the first thickened portion 1101” can be understood as, in the first direction z, the first main body portion 1100 and the first thickened portion 1101 are arranged with each other, and the first main body portion 1100 is farther away from the opening 11a than the first thickened portion 1101.

[0099] Exemplarily, one possibility is that the first main body portion 1100 and the first thickened portion 1101 are connected in sequence along the first direction z, the first thickened portion 1101 is away from the end of the first main body portion 1100 to form a portion of the opening 11a, and the first thickened portion 1101 is connected to the end cover; or, the second possibility is that the first wall 110 also includes a first connecting section, the first connecting section, the first thickened portion 1101 and the first main body portion 1100 are distributed in sequence along the first direction z, the end of the first connecting section forms a portion of the opening 11a, the first connecting section can be connected to the end cover 14, and the thickness of the first connecting section can be greater than, equal to or less than the maximum thickness of the first thickened portion 1101.

[0100] “The maximum thickness of the first thickened portion 1101 is greater than the thickness of the first main body 1100” can be understood as that the maximum thickness of the first thickened portion 1101 is greater than the thickness of the first main body 1100, or it can be understood as that the strength of the first thickened portion 1101 is greater than the strength of the first body. In some embodiments, the first thickened portion 1101 is a structure of uniform wall thickness, and its wall thickness may be greater than the thickness of the first main body 1100. In other embodiments, the first thickened portion 1101 may not be a structure of uniform wall thickness, and the wall thickness of the portion with the largest wall thickness may be greater than the maximum wall thickness of the first main body 1100. In some embodiments, the first thickened portion 1101 is connected to the first main body 1100, and the wall thickness of the interface between the first thickened portion 1101 and the first main body 1100 may gradually increase so that the first thickened portion 1101 and the first main body 1100 have a smooth transition.

[0101] In some embodiments, the first thickened portion 1101 protrudes from the inner side of the first body portion 1100, that is, the portion of the first thickened portion 1101 protruding from the first body portion 1100 can be located inside the housing 11. In other embodiments, the first thickened portion 1101 protrudes from the outer side of the first body portion 1100, that is, the portion of the first thickened portion 1101 protruding from the first body portion 1100 can be located outside the housing 11. In other embodiments, the first thickened portion 1101 can protrude from both the outer side and the inner side of the first body portion 1100, that is, a portion of the first thickened portion 1101 protruding from the first body portion 1100 can be located outside the housing 11, and a portion can be located inside the housing 11.

[0102] In some embodiments, the first body portion 1100 may have a uniform wall thickness. In other embodiments, the wall thickness of the first body portion 1100 may be unevenly distributed, and may have a non-uniform wall thickness.

[0103] “The corner area 112 has a second main body portion 1120 and a second thickened portion 1121 arranged along the first direction z, and the second main body portion 1120 is farther away from the opening 11a than the second thickened portion 1121” can be understood as, in the first direction z, the second main body portion 1120 and the second thickened portion 1121 are arranged with each other, and the second main body portion 1120 is farther away from the opening 11a than the second thickened portion 1121.

[0104] Exemplarily, one possibility is that the second main body portion 1120 and the second thickened portion 1121 are connected in sequence along the first direction z, the second thickened portion 1121 is away from the end of the second main body portion 1120 to form a portion of the opening 11a, and the second thickened portion 1121 is connected to the end cover; or, the second possibility is that the corner area 112 also includes a second connecting section, the second connecting section, the second main body portion 1120 and the second thickness portion are distributed in sequence along the first direction z, the end of the second connecting section forms a portion of the opening 11a, and the second connecting section can be connected to the end cover.

[0105] “The maximum thickness of the second thickened portion 1121 is greater than the thickness of the second main body portion 1120” can be understood as that the maximum thickness of the second thickened portion 1121 is greater than the thickness of the second main body portion 1120, or it can be understood as that the strength of the second thickened portion 1121 is greater than the strength of the second body. In some embodiments, the second thickened portion 1121 is a structure of uniform wall thickness, and its wall thickness may be greater than the thickness of the second main body portion 1120. In other embodiments, the second thickened portion 1121 may not be a structure of uniform wall thickness, and the wall thickness of the portion with the largest wall thickness may be greater than the maximum wall thickness of the second main body portion 1120. In some embodiments, the second thickened portion 1121 is connected to the second main body portion 1120, and the wall thickness of the interface between the second thickened portion 1121 and the second main body portion 1120 may gradually increase so that the second thickened portion 1121 and the second main body portion 1120 have a smooth transition.

[0106] In some embodiments, the second body portion 1120 may have a uniform wall thickness. In other embodiments, the wall thickness of the second body portion 1120 may be unevenly distributed, and may have a non-uniform wall thickness.

[0107] In some embodiments, the second thickened portion 1121 protrudes from the inner side of the second body portion 1120, that is, the portion of the second thickened portion 1121 protruding from the second body portion 1120 can be located inside the housing 11. In other embodiments, the second thickened portion 1121 protrudes from the outer side of the second body portion 1120, that is, the portion of the second thickened portion 1121 protruding from the second body portion 1120 can be located outside the housing 11. In other embodiments, the second thickened portion 1121 can protrude from both the outer side and the inner side of the second body portion 1120, that is, a portion of the second thickened portion 1121 protruding from the second body portion 1120 can be located outside the housing 11, and a portion can be located inside the housing 11.

[0108] In some embodiments, the relationship between the maximum thickness of the first thickened portion 1101 and the maximum thickness of the second thickened portion 1121 is not limited, and possible solutions include: the maximum thickness of the first thickened portion 1101 is less than the maximum thickness of the second thickened portion 1121; the maximum thickness of the first thickened portion 1101 is greater than the maximum thickness of the second thickened portion 1121; or, the maximum thickness of the first thickened portion 1101 is equal to the maximum thickness of the second thickened portion 1121.

[0109] In the above solution, by providing a first thickened portion 1101 with a greater maximum thickness on the first wall 110, the problem of a heat-affected zone of lower strength formed in the housing 11 due to welding, which can cause the first wall 110 to crack due to insufficient strength when impacted, can be alleviated, thereby improving the reliability of the battery 100. At the same time, by providing a second thickened portion 1121 with a greater maximum thickness in the corner region 112, the strength of the corner region 112 corresponding to the opening 11a can be improved, improving the problem of stress concentration in the corner region 112 corresponding to the opening 11a during demolding caused by the provision of the first thickened portion 1101, which can cause cracking in the corner region 112, thereby improving the reliability of the battery cell 10.

[0110] According to some embodiments of the present application, the maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the first thickened portion 1101 .

[0111] “The maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the first thickened portion 1101” can be understood as that the maximum thickness of the thickened portion of the corner area 112 is greater than the maximum thickness of the thickened portion of the first wall 110, or it can be understood as that the strength of the second thickened portion 1121 is greater than the strength of the first thickened portion 1101.

[0112] In some embodiments, the minimum thickness of the second thickened portion 1121 may be greater than the maximum thickness of the first thickened portion 1101. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than or equal to the maximum thickness of the first thickened portion 1101. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than or equal to the minimum thickness of the first thickened portion 1101.

[0113] In the above scheme, by setting the maximum thickness of the second thickened portion 1121 to be greater than the maximum thickness of the first thickened portion 1101, the strength of the corner area 112 corresponding to the opening 11a can be effectively improved. On the one hand, the overall thickness of the shell 11 can be effectively increased, and the risk of the shell 11 being cracked by impact can be reduced. On the other hand, the stress concentration during the manufacturing process of the shell 11 can be effectively improved, which causes the problem of cracking in the corner area 112, so that the battery cell 10 has higher reliability.

[0114] In other embodiments, the maximum thickness of the second thickened portion 1121 may be smaller than the maximum thickness of the first thickened portion 1101 ; in other embodiments, the maximum thickness of the second thickened portion 1121 may be smaller than the minimum thickness of the first thickened portion 1101 .

[0115] According to some embodiments of the present application, referring to Figures 7 and 9 , the maximum thickness of the second thickened portion 1121 is T1, the thickness of the second body portion 1120 is T2, the maximum thickness of the first thickened portion 1101 is t1, and the thickness of the first body portion 1100 is t2, satisfying E ≥ F, E = (T1 - T2) / T2, and F = (t1 - t2) / t2.

[0116] In some embodiments, the corner area 112 of the shell 11 can be regarded as a portion that is locally thickened based on the second main body 1120 to form the second thickened portion 1121, T1-T2 is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120, and E is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120 divided by the thickness of the second main body 1120, that is, E can be regarded as the degree of thickening of the second thickened portion 1121 compared with the second main body 1120.

[0117] In some embodiments, the first wall 110 of the shell 11 can be regarded as a portion that is locally thickened based on the first main body 1100 to form the first thickened portion 1101, t1-t2 is the difference between the maximum thickness of the first thickened portion 1101 and the thickness of the first main body 1100, and F is the difference between the maximum thickness of the first thickened portion 1101 and the thickness of the first main body 1100 divided by the thickness of the first main body 1100, that is, F can be regarded as the degree of thickening of the first thickened portion 1101 compared to the first main body 1100.

[0118] “E≥F” can be understood as that the thickness of the second thickened portion 1121 compared to the second portion is greater than or equal to the thickness of the first thickened portion 1101 compared to the first main body 1100 .

[0119] In the above scheme, by limiting the degree E of thickening of the second thickened portion 1121 compared to the second main body portion 1120 to no less than the degree F of thickening of the first thickened portion 1101 compared to the first main body portion 1100, the problem of stress concentration during the manufacturing process of the shell 11 due to the setting of the first thickened portion 1101, resulting in cracking of the corner area 112, can be effectively improved, so that the battery cell 10 has higher reliability.

[0120] In other embodiments, the second thickened portion 1121 is thicker than the second portion 1121 than the first main body 1100 .

[0121] According to some embodiments of the present application, the maximum thickness of the second thickened portion 1121 is T1, and the thickness of the second body portion 1120 is T2, satisfying 0<E<30%, E=(T1-T2) / T2.

[0122] In some embodiments, the corner area 112 of the shell 11 can be regarded as a portion that is locally thickened based on the second main body 1120 to form the second thickened portion 1121, T1-T2 is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120, and E is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120 divided by the thickness of the second main body 1120, that is, E can be regarded as the degree of thickening of the second thickened portion 1121 compared with the second main body 1120.

[0123] In some embodiments, the value of E can be greater than 0 and less than 30%. For example, E can take the following values: 1%, 2%, 3%, 4%...28%, 29%, any value between two adjacent values, or any value between 29% and 30%.

[0124] In some embodiments, T2 may be 0.6 mm; T1 may be a value greater than 0.6 mm, for example, T1 may be 0.65%, 0.7% or 0.75%, and the corresponding E values ​​are 8.3%, 16.7% and 25%, respectively.

[0125] In the above scheme, by limiting the degree E of thickening of the second thickened portion 1121 compared to the second main body portion 1120, on the one hand, the strength of the corner area 112 can be improved and the risk of cracking of the corner area 112 due to stress concentration can be reduced; on the other hand, the risk of bulging of the corner area 112 and deformation of the outer shell due to excessive stress can be reduced, so that the battery cell 10 has higher reliability.

[0126] According to some embodiments of the present application, 0<E≤16.7% is satisfied.

[0127] In some embodiments, the value of E may be greater than 0 and less than or equal to 16.7%. For example, E may be 1%, 2%, 3%, 4%...16%, 16.7% or any value between two adjacent values.

[0128] In the above scheme, by limiting the degree E of thickening of the second thickened portion 1121 relative to the second main body portion 1120 to no more than 16.7%, on the one hand, it can take into account the improvement of the problems of cracking caused by stress concentration and deformation caused by excessive stress; on the other hand, it can effectively control the weight of the shell 11, which is beneficial to the improvement of the weight energy density of the battery cell 10.

[0129] According to some embodiments of the present application, along the first direction z, a distance from one end of the second thickened portion 1121 away from the opening 11 a to the opening 11 a is L1, satisfying 0<L1≤20 mm.

[0130] In some embodiments, the value of L1 can be a value greater than 0 and less than or equal to 20 mm. For example, the value of L1 can be 1 mm, 2 mm, 3 mm, 4 mm...15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values, or any value between 0 mm and 1 mm.

[0131] In some embodiments, the first direction z can be regarded as the up and down direction, and "the distance from the end of the second thickened portion 1121 away from the opening 11a to the opening 11a is L1" can be understood as, the second main body portion 1120 is L1 below the opening, and the second thickened portion 1121 is above the second main body portion 1120, or it can be understood as, along the first direction z, the portion away from the opening 11a can define a dividing line, the second thickened portion 1121 is above the dividing line, and the second main body portion 1120 is below the dividing line.

[0132] In the above scheme, along the first direction z, by providing a second thickened portion 1121 in the corner area 112 within 20 mm below the opening 11a, the strength of the portion of the corner area 112 corresponding to the opening 11a can be effectively improved, and the risk of cracking of the corner area 112 due to stress concentration in the portion of the corner area 112 corresponding to the opening 11a during the manufacturing process of the shell 11 caused by thickening the first wall 110 is reduced, so that the battery cell 10 has higher reliability.

[0133] According to some embodiments of the present application, along the first direction z, a distance from one end of the first thickened portion 1101 away from the opening 11 a to the opening 11 a is L2, satisfying 0<L2≤20 mm.

[0134] In some embodiments, the value of L1 can be a value greater than 0 and less than or equal to 20 mm. For example, the value of L1 can be 1 mm, 2 mm, 3 mm, 4 mm...15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values, or any value between 0 mm and 1 mm.

[0135] In some embodiments, the first direction z can be regarded as the up and down direction, and "the distance from the end of the first thickened portion 1101 away from the opening 11a to the opening 11a is L2" can be understood as, the first main body portion 1100 is L2 below the opening, and the first thickened portion 1101 is above the first main body portion 1100, or it can be understood as, along the first direction z, the portion away from the opening 11a can define a dividing line, the first thickened portion 1101 is above the dividing line, and the first main body portion 1100 is below the dividing line.

[0136] In the above scheme, along the first direction z, by providing a second thickened portion 1121 in the corner area 112 within 20 mm below the opening 11a, the strength of the portion of the corner area 112 corresponding to the opening 11a can be effectively improved, and the risk of cracking of the corner area 112 due to stress concentration in the portion of the corner area 112 corresponding to the opening 11a during the manufacturing process of the shell 11 caused by thickening the first wall 110 is reduced, so that the battery cell 10 has higher reliability.

[0137] According to some embodiments of the present application, the area of ​​the outer surface of the first wall 110 is greater than the area of ​​the outer surface of the second wall 113 .

[0138] In some embodiments, the outer surface of the first wall 110 may be the larger surface of the battery cell 10 . When the battery cell 10 is charged or discharged, the expansion force generated inside the battery cell 10 mainly acts on the first wall 110 .

[0139] In the above solution, by providing the first thickened portion 1101 on the first wall 110 with a larger outer surface area, the risk of the shell 11 being easily cracked by impact can be effectively improved, so that the battery cell 10 has higher reliability.

[0140] In other embodiments of the present application, the area of ​​the outer surface of the first wall 110 is equal to the area of ​​the outer surface of the second wall 113 ; or, the area of ​​the outer surface of the first wall 110 is smaller than the area of ​​the outer surface of the second wall 113 .

[0141] According to some embodiments of the present application, as shown in FIG4 , housing 11 includes two first walls 110 disposed opposite each other along a second direction x, and two second walls 113 disposed opposite each other along a third direction y. The second direction x, the third direction y, and the first direction z are mutually perpendicular. Adjacent first walls 110 and second walls 113 are connected by corresponding corner regions 112. The first walls 110, the second walls 113, and the corner regions 112 collectively define an opening 11a.

[0142] In some embodiments, the housing 11 may be in a substantially rectangular parallelepiped shape, with its main structure comprising two opposing first walls 110 and two opposing second walls 113, with the first walls 110 and second walls 113 disposed adjacent to each other. Adjacent first walls 110 and second walls 113 are transitionally connected by corner regions 112. In some embodiments, the corner regions 112 may be arc-shaped.

[0143] In the above solution, the housing 11 can be a square structure. By thickening two walls arranged opposite each other along the second direction x, i.e., providing a first thickened portion 1101, the structural strength of the housing 11 can be effectively improved, reducing the risk of cracking of the housing 11 due to impact. At the same time, by thickening the corner area 112 between the two adjacent walls, i.e., providing a second thickened portion 1121, the problem of cracking in the corner area 112 due to stress concentration can be alleviated, thereby ensuring higher reliability of the battery cell 10.

[0144] According to some embodiments of the present application, please refer to Figures 5-9, the second wall 113 has a third main body portion 1130 and a third thickened portion 1131 arranged along the first direction z, the third main body portion 1130 is farther away from the opening 11a than the third thickened portion 1131, and the maximum thickness of the third thickened portion 1131 is greater than the thickness of the third main body portion 1130.

[0145] “The second wall 113 has a third main body portion 1130 and a third thickened portion 1131 arranged along the first direction z, and the third main body portion 1130 is farther away from the opening 11a than the third thickened portion 1131” can be understood as, in the first direction z, the third main body portion 1130 and the third thickened portion 1131 are arranged with each other, and the third main body portion 1130 is farther away from the opening 11a than the third thickened portion 1131.

[0146] Exemplarily, one possibility is that the third main body portion 1130 and the third thickened portion 1131 are connected in sequence along the first direction z, the third thickened portion 1131 is away from the end of the third main body portion 1130 to form a portion of the opening 11a, and the third thickened portion 1131 is connected to the end cover; or, the second possibility is that the second wall 113 also includes a third connecting segment, the third connecting segment, the third main body portion 1130 and the third thickness portion are distributed in sequence along the first direction z, the end of the third connecting segment forms a portion of the opening 11a, and the third connecting segment can be connected to the end cover 14.

[0147] “The maximum thickness of the third thickened portion 1131 is greater than the thickness of the third main body portion 1130” can be understood as that the maximum thickness of the third thickened portion 1131 is greater than the thickness of the third main body portion 1130, or it can be understood as that the strength of the third thickened portion 1131 is greater than the strength of the third body portion. In some embodiments, the third thickened portion 1131 is a structure of uniform wall thickness, and its wall thickness may be greater than the thickness of the third main body portion 1130. In other embodiments, the third thickened portion 1131 may not be a structure of uniform wall thickness, and the wall thickness of the portion with the largest wall thickness may be greater than the maximum wall thickness of the third main body portion 1130. In some embodiments, the third thickened portion 1131 is connected to the third main body portion 1130, and the wall thickness of the interface between the third thickened portion 1131 and the third main body portion 1130 may gradually increase so that the third thickened portion 1131 and the third main body portion 1130 have a smooth transition.

[0148] In some embodiments, the third thickened portion 1131 protrudes from the inner side of the third body portion 1130, that is, the portion of the third thickened portion 1131 protruding from the third body portion 1130 can be located inside the housing 11. In other embodiments, the third thickened portion 1131 protrudes from the outer side of the third body portion 1130, that is, the portion of the third thickened portion 1131 protruding from the third body portion 1130 can be located outside the housing 11. In other embodiments, the third thickened portion 1131 can protrude from both the outer side and the inner side of the third body portion 1130, that is, a portion of the third thickened portion 1131 protruding from the third body portion 1130 can be located outside the housing 11, and a portion can be located inside the housing 11.

[0149] In some embodiments, the third body portion 1130 may have a uniform wall thickness. In other embodiments, the wall thickness of the third body portion 1130 may be unevenly distributed, and may have a non-uniform wall thickness.

[0150] According to some embodiments of the present application, the maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the third thickened portion 1131 .

[0151] “The maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the third thickened portion 1131” can be understood as that the maximum thickness of the thickened portion of the corner area 112 is greater than the maximum thickness of the thickened portion of the second wall 113, or it can be understood as that the strength of the second thickened portion 1121 is greater than the strength of the third thickened portion 1131.

[0152] In some embodiments, the minimum thickness of the second thickened portion 1121 may be greater than the maximum thickness of the third thickened portion 1131. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than or equal to the maximum thickness of the third thickened portion 1131. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than or equal to the minimum thickness of the third thickened portion 1131.

[0153] In the above scheme, by setting the maximum thickness of the second thickened portion 1121 to be greater than the maximum thickness of the third thickened portion 1131, the strength of the portion of the corner area 112 corresponding to the opening 11a can be effectively improved. On the one hand, the overall thickness of the shell 11 can be effectively increased, and the risk of the shell 11 being cracked by impact can be reduced. On the other hand, the problem of stress concentration in the corner area 112 during the manufacturing process of the shell 11, which causes cracking of the corner area 112, can be effectively improved, so that the battery cell 10 has higher reliability.

[0154] In other embodiments, the maximum thickness of the second thickened portion 1121 may be smaller than the maximum thickness of the third thickened portion 1131 ; in other embodiments, the maximum thickness of the second thickened portion 1121 may be smaller than the minimum thickness of the third thickened portion 1131 .

[0155] According to some embodiments of the present application, referring to Figures 7 and 9, the maximum thickness of the second thickened portion 1121 is T1, the thickness of the second main body portion 1120 is T2, the maximum thickness of the third thickened portion 1131 is t3, and the thickness of the third main body portion 1130 is t4, satisfying E≥G, E=(T1-T2) / T2, G=(t3-t4) / t4.

[0156] In some embodiments, the corner area 112 of the shell 11 can be regarded as a portion that is locally thickened based on the second main body 1120 to form the second thickened portion 1121, T1-T2 is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120, and E is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body 1120 divided by the thickness of the second main body 1120, that is, E can be regarded as the degree of thickening of the second thickened portion 1121 compared with the second main body 1120.

[0157] In some embodiments, the second wall 113 of the shell 11 can be regarded as a portion that is locally thickened based on the third main body 1130 to form the third thickened portion 1131, t3-t4 is the difference between the maximum thickness of the third thickened portion 1131 and the thickness of the third main body 1130, and G is the difference between the maximum thickness of the third thickened portion 1131 and the thickness of the third main body 1130 divided by the thickness of the third main body 1130, that is, G can be regarded as the degree of thickening of the third thickened portion 1131 compared with the third main body 1130.

[0158] “E≥G” can be understood as that the thickness of the second thickened portion 1121 compared to the second main body portion 1120 is greater than or equal to the thickness of the third thickened portion 1131 compared to the third main body portion 1130 .

[0159] In the above scheme, by limiting the degree E of thickening of the second thickened portion 1121 compared to the second main body portion 1120 to no less than the degree G of thickening of the third thickened portion 1131 compared to the third main body portion 1130, the problem of stress concentration at the corner portion corresponding to the opening 11a during the manufacturing process of the shell 11 due to the setting of the third thickened portion 1131, resulting in cracking of the corner area 112, can be effectively improved, so that the battery cell 10 has higher reliability.

[0160] In other embodiments, the thickness of the second thickened portion 1121 relative to the second main body portion 1120 is smaller than the thickness of the third thickened portion 1131 relative to the third main body portion 1130 .

[0161] According to some embodiments of the present application, referring to FIG. 4 , along the first direction z, a distance from one end of the third thickened portion 1131 away from the opening 11 a to the opening 11 a is L3, satisfying 0<L3≤20 mm.

[0162] In some embodiments, the value of L3 can be a value greater than 0 and less than or equal to 20 mm. For example, the value of L3 can be 1 mm, 2 mm, 3 mm, 4 mm...15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values, or any value between 0 mm and 1 mm.

[0163] In some embodiments, the first direction z can be regarded as the up and down direction, and "the distance from the end of the third thickened portion 1131 away from the opening 11a to the opening 11a is L3" can be understood as, the third main body portion 1130 is L3 below the opening, and the third thickened portion 1131 is above the third main body portion 1130, or it can be understood as, along the first direction z, the portion away from the opening 11a can define a dividing line, the third thickened portion 1131 is above the dividing line, and the third main body portion 1130 is below the dividing line.

[0164] In the above scheme, along the first direction z, by providing a third thickened portion 1131 in the area of ​​the second wall 113 within 20 mm below the opening 11a, the strength of the portion of the second wall 113 corresponding to the opening 11a can be effectively improved, and the risk of the second wall 113 being easily cracked by impact can be reduced, so that the battery cell 10 has higher reliability.

[0165] In some embodiments, the second wall 113 has a uniform wall thickness.

[0166] “The second wall 113 has a uniform wall thickness structure” can be understood as, along the first direction z, the wall thickness of any part of the second wall 113 is equal. It can also be understood as, the present application provides a battery cell 10, the first wall 110 and the corner area 112 of the battery cell 10 are partially provided with thickened parts, while the second wall 113 is not provided with thickened parts; or it can be understood as, the present application provides a battery cell 10, the first wall 110 and the corner area 112 of the battery cell 10 are partially provided with thickened parts, while the second wall 113 is thickened as a whole.

[0167] In the above scheme, under the condition that the first thickened portion 1101 is set on the first wall 110 and the second thickened portion 1121 is set in the corner area 112, the second wall 113 is set to a uniform wall thickness structure. On the one hand, it can ensure the strength of the shell 11 to a certain extent and reduce the risk of cracking of the shell 11. On the other hand, it can effectively control the weight of the shell 11 and reduce the impact of thickening the wall on the weight energy density of the battery cell 10.

[0168] According to some embodiments of the present application, please refer to FIG. 4 and FIG. 12 , FIG. 12 is an enlarged view of point L in FIG. 4 .

[0169] The battery cell 10 also includes an end cap 14 that seals the opening 11a. The third thickened portion 1131 includes a first segment 1131a and a second segment 1131b that are interconnected. The first segment 1131a, the second segment 1131b, and the third body portion 1130 (please refer to FIG. 9 for understanding) are arranged sequentially along the first direction z. The maximum thickness of the second segment 1131b is greater than that of the third body portion 1130, and the maximum thickness of the second segment 1131b is greater than that of the first segment 1131a. The end cap 14 is connected to the first segment 1131a.

[0170] In some embodiments, the third thickened portion 1131 may include a multi-segment structure along the first direction z. For example, along the first direction z, the third thickened portion 1131 includes a first segment 1131a and a second segment 1131b that are interconnected. The first segment 1131a is connected to the end cap 14. The connection between the first segment 1131a and the end cap 14 may include welding. The second segment 1131b is connected to the third body portion 1130. The maximum thickness of the second segment 1131b may be the maximum thickness of the third thickened portion 1131, that is, the maximum thickness of the second wall 113.

[0171] In some embodiments, the maximum thickness of the first segment 1131a may be smaller than the maximum thickness of the second segment 1131b, and the maximum thickness of the first segment 1131a may be greater than, equal to, or less than the thickness of the third body portion 1130. Alternatively, the minimum thickness of the first segment 1131a may be greater than, equal to, or less than the thickness of the third body portion 1130.

[0172] In the above solution, by setting the thickness of the second section 1131b of the third thickened portion 1131 to be greater than the thickness of the third main body portion 1130, the strength of the second wall 113 can be effectively improved, and the risk of the second wall 113 being cracked by impact can be reduced, so that the battery cell 10 has higher reliability.

[0173] According to some embodiments of the present application, as shown in FIG. 4 and FIG. 12 , a first step surface 1131 c is formed between the second section 1131 b and the first section 1131 a , and the end cover 14 overlaps the first step surface 1131 c .

[0174] In some embodiments, the maximum thickness of the second section 1131b is greater than the maximum thickness of the first section 1131a, thereby forming a first step surface 1131c between the second section 1131b and the first section 1131a. In some embodiments, the first step surface 1131c can be inclined or perpendicular to the first direction z. The first step surface 1131c being inclined to the first direction z can be understood as forming an angle between the first step surface 1131c and the first direction z, and the angle is not 90°. "The end cap 14 overlaps the first step surface 1131c" can be understood as the first step surface 1131c can support the end cap 14 and can position the end cap 14 when the end cap 14 is assembled.

[0175] In the above solution, the first step surface 1131c formed between the second section 1131b and the first section 1131a can enable the end cover 14 to overlap the first step surface 1131c, thereby facilitating the positioning and assembly of the end cover 14; at the same time, the first step surface 1131c supports the end cover 14, reducing the risk of collapse of the end cover 14, thereby making the battery cell 10 have higher reliability.

[0176] According to some embodiments of the present application, the battery cell 10 further includes an end cap 14 that seals the opening 11a. The second thickened portion 1121 includes a third segment 1121a and a fourth segment 1121b that are interconnected. The third segment 1121a, the fourth segment 1121b, and the second body portion 1120 are sequentially arranged along the first direction z. The maximum thickness of the fourth segment 1121b is greater than the thickness of the second body portion 1120, and the maximum thickness of the fourth segment 1121b is greater than the maximum thickness of the third segment 1121a. The end cap 14 is connected to the third segment 1121a.

[0177] In some embodiments, along the first direction z, the second thickened portion 1121 may include a multi-segment structure. For example, along the first direction z, the second thickened portion 1121 includes a third segment 1121a and a fourth segment 1121b that are interconnected. The third segment 1121a is connected to the end cap 14. The connection between the third segment 1121a and the end cap 14 may include welding. The fourth segment 1121b is connected to the second body portion 1120. The maximum thickness of the fourth segment 1121b may be the maximum thickness of the second thickened portion 1121, that is, the maximum thickness of the corner region 112.

[0178] In some embodiments, the maximum thickness of the third segment 1121a may be smaller than the maximum thickness of the fourth segment 1121b, and the maximum thickness of the third segment 1121a may be greater than, equal to, or less than the thickness of the second body portion 1120. Alternatively, the minimum thickness of the third segment 1121a may be greater than, equal to, or less than the thickness of the second body portion 1120.

[0179] In the above solution, by setting the thickness of the fourth section 1121b of the second thickened portion 1121 to be greater than the thickness of the second main body portion 1120, the strength of the corner area can be effectively improved, and the risk of the corner area being impacted or cracked due to stress concentration during demolding can be reduced, so that the battery cell 10 has higher reliability.

[0180] According to some embodiments of the present application, a second step surface 1121c is formed between the fourth section 1121b and the third section 1121c, and the end cover 14 overlaps the second step surface 1121c.

[0181] In some embodiments, the maximum thickness of the fourth section 1121b is greater than the maximum thickness of the third section 1121c, thereby forming a second step surface 1121c between the fourth section 1121b and the third section 1121c. In some embodiments, the second step surface 1121c can be inclined or perpendicular to the first direction z. The inclination of the second step surface 1121c to the first direction z can be understood as forming an angle between the second step surface 1121c and the first direction z, which is not 90°.

[0182] “The end cover 14 overlaps the second step surface 1121c” can be understood as the second step surface 1121c can support the end cover 14 and can position the end cover 14 when assembling the end cover 14.

[0183] In the above scheme, the second step surface 1121c formed between the fourth section 1121b and the third section 1121c can enable the end cover 14 to overlap the second step surface 1121c, thereby facilitating the positioning and assembly of the end cover 14; at the same time, the second step surface 1121c supports the end cover 14, which can reduce the risk of collapse of the end cover 14, thereby making the battery cell 10 have higher reliability.

[0184] According to some embodiments of the present application, please refer to Figure 13, which is a schematic diagram of the end cover and corner area in some embodiments of the present application.

[0185] The battery cell 10 also includes an end cover 14, which is welded to the second thickened portion 1121 to form a welding zone 114. The average grain size of the second thickened portion 1121 other than the welding zone 114 is larger than the average grain size of the second main body portion 1120. The average grain size is the average grain size of the grains in the first direction z.

[0186] The welding zone 114 is a region formed by welding the second thickened portion 1121 and the end cover 14 . In some embodiments, the welding zone 114 may be referred to as a welding region or a welding mark.

[0187] “The portion of the second thickened portion 1121 other than the weld zone 114 ” may be understood as the portion of the second thickened portion that is not connected to the end cover 14 , that is, the portion of the second thickened portion 1121 that is not in the weld zone 114 .

[0188] In some embodiments, the test method for average grain size refers to the following standards: GB / T 6394-2017 "Method for Determination of Average Grain Size of Metals" and GB / T 13298-2017 "Metallic Material Grain Size Determination by Electron Rearview Microscope Method".

[0189] In the above scheme, by limiting the average grain size of the second thickened portion 1121 other than the welding zone 114 to be larger than the average grain size of the second main body portion 1120, it is beneficial to enhance the strength of the second thickened portion 1121, so that the corner area 112 has higher strength, and reduces the risk of the corner area 112 being cracked near the welding zone 114 due to impact and the risk of the corner area 112 being cracked due to stress concentration during demolding, so that the battery cell 10 has higher reliability.

[0190] In other embodiments, the end cap 14 is welded to the first thickened portion 1101 to form a fusion zone. The average grain size of the first thickened portion 1101, excluding the fusion zone, is greater than the average grain size of the first main body 1100. The average grain size is the average grain size of the grains in the first direction z. In other embodiments, the end cap 14 is welded to the third thickened portion 1131 to form a fusion zone. The average grain size of the third thickened portion 1131, excluding the fusion zone, is greater than the average grain size of the third main body 1130. The average grain size is the average grain size of the grains in the first direction z.

[0191] According to some embodiments of the present application, in a cross section of the corner region 112 parallel to the first direction z, the number of grains in the portion of the second thickened portion 1121 below the fusion zone 114 is greater than or equal to 15 in the width direction of the cross section.

[0192] In some embodiments, the “width direction of the cross section” may be the thickness direction of the corner region 112 .

[0193] In some embodiments, "the portion of the second thickened portion 1121 located below the welding zone 114 has a number of grains greater than or equal to 15 in the width direction of the cross-section" can be understood as the portion of the second thickened portion 1121 located between the welding zone 114 and the second main body portion 1120, and the number of grains in this portion in the thickness direction of the corner zone 112 can be 15, 16, 17 or more.

[0194] In the above solution, the number of grains in the width direction of the cross section is greater than or equal to 15, which is beneficial to enhancing the strength of the second thickened portion 1121 and improving the reliability of the battery 100.

[0195] In other embodiments, in a cross-section of the first wall 110 parallel to the first direction z, the portion of the first thickened portion 1101 located below the fusion zone 114, along the width direction of the cross-section, has a number of grains greater than or equal to 15. In other embodiments, in a cross-section of the second wall 113 parallel to the first direction z, the portion of the third thickened portion 1131 located below the fusion zone 114, along the width direction of the cross-section, has a number of grains greater than or equal to 15.

[0196] According to some embodiments of the present application, an average grain size of a portion of the second thickened portion 1121 excluding the fusion zone 114 is in a range of 70 μm to 1200 μm.

[0197] And / or, in some embodiments, the average grain size of the second body portion 1120 is in a range of 30 micrometers to 1000 micrometers. And / or, in some embodiments, the maximum wall thickness of the end cap 14 is in a range of 0.25 mm to 3 mm.

[0198] In some embodiments, the average grain size of the second thickened portion 1121 excluding the fusion zone 114 may be, but is not limited to, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, etc., or any value between adjacent values.

[0199] In some embodiments, the average grain size of the second main body 1120 can be but is not limited to 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, etc., or any value between adjacent values.

[0200] In some embodiments, the test scheme for average grain size can refer to: GB / T 6394-2002 "Method for Determination of Grain Size of Metallic Materials" and GB / T 13298-2017 "Metallic Materials - Determination of Grain Size by Electron Rearview Microscope Method".

[0201] In some embodiments, the maximum wall thickness of the end cap 14 can be, but is not limited to, 0.25 mm, 0.35 mm, 0.45 mm, 0.55 mm, 0.65 mm, 0.75 mm, 0.85 mm, . . . 2.75 mm, 2.85 mm, 2.95 mm, 3 mm, etc., or any value between adjacent values.

[0202] In the above solution, the average grain size of the second thickened portion 1121 and / or the average grain size of the second body portion 1120 satisfy the above relationship, which is beneficial to enhancing the strength of the second thickened portion 1121 and making the battery cell 10 have higher reliability.

[0203] According to some embodiments of the present application, the present application further provides a battery 100 , which includes the battery cell 10 described above.

[0204] In some embodiments, a battery 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is housed within the housing 20. The housing 20 is used to provide a space for accommodating the battery cell 10. In the battery 100, there may be one or more battery cells 10, and each battery cell 10 may be fixed to the housing 20 via a connector (e.g., a bolt) or by adhesive bonding.

[0205] According to some embodiments of the present application, the present application further provides an energy storage device, which includes the battery cell 10 described above.

[0206] The energy storage device may include an energy storage cabinet, which includes a cabinet body and one or more battery cells 10, or one or more batteries 100, disposed within the cabinet body. The cabinet body may include a cabinet body and a cabinet door. The one or more battery cells 10 are disposed within the cabinet body. The cabinet door seals an opening 11a of the cabinet body to enclose the one or more battery cells 10 in a closed space, thereby reducing interference from external substances on the battery cells 10.

[0207] According to some embodiments of the present application, the present application further provides an electrical device, wherein the energy storage device includes the battery cell 10 described above.

[0208] In some embodiments, the power-consuming device may be a vehicle, wherein a controller, a motor, and a battery cell 10 may be provided inside the vehicle, and the controller is used to control the battery cell 10 to supply power to the motor.

[0209] According to some embodiments of the present application, please refer to Figures 4 to 11. A battery cell 10 is provided, which includes a shell 11 and an end cover. Along the first direction z, the shell 11 has an opening 11a, and the electrode assembly 12 is arranged inside the shell 11. The end cover is connected to the shell 11 to close the opening 11a, so that the electrode assembly 12 is located in a closed space. Along the second direction x, the shell 11 includes two first walls 110 arranged opposite to each other. Along the third direction y, the shell 11 includes two second walls 113 arranged opposite to each other. The second direction x, the third direction y and the first direction z are perpendicular to each other. Adjacent first walls 110 and second walls 113 are connected by corresponding corner areas 112, and the first wall 110, the second wall 113 and the corner area 112 together enclose the opening 11a.

[0210] The first wall 110 includes a first main portion 1100 and a first thickened portion 1101 arranged along a first direction z. The first main portion 1100 is further away from the opening 11a than the first thickened portion 1101, and the maximum thickness of the first thickened portion 1101 is greater than the thickness of the first main portion 1100. The second wall 113 includes a third main portion 1130 and a third thickened portion 1131 arranged along the first direction z. The third main portion 1130 is further away from the opening 11a than the third thickened portion 1131, and the maximum thickness of the third thickened portion 1131 is greater than the thickness of the third main portion 1130.

[0211] The corner area 112 has a second main body portion 1120 and a second thickened portion 1121 arranged along the first direction z. The second main body portion 1120 is farther away from the opening 11a than the second thickened portion 1121 . The maximum thickness of the second thickened portion 1121 is greater than that of the second main body portion 1120 .

[0212] In the above solution, by providing the first thickened portion 1101 on the first wall 110 and the third thickened portion 1131 on the second wall 113, the problem of a heat-affected zone of low strength formed by welding on the housing 11, which can cause the housing 11 to crack due to insufficient strength when impacted, can be alleviated, thereby improving the reliability of the battery 100. At the same time, by providing the second thickened portion 1121 in the corner area 112, the strength of the corner area 112 corresponding to the opening 11a can be improved, and the problem of stress concentration caused by the first thickened portion 1101 and the second thickened portion 1121 during demolding, which can cause cracking in the corner area 112, can be alleviated, thereby improving the reliability of the battery cell 10.

[0213] In some embodiments, the thickness of the second thickened portion 1121 is T1, and the thickness of the second body portion 1120 is T2, satisfying 0<E<30%, E=(T1-T2) / T2. In other embodiments, 0<E≤16.7%.

[0214] For example, based on the battery cell 10 provided above, different E values ​​and demoulding feasibility were tested and verified. The test verification results can be seen in the following table:

[0215] As can be seen from the above table, the degree of thickening of the corner area 112 can be within a certain range. For example, the thickness of the second thickened portion 1121 is T1, and the thickness of the second body portion 1120 is T2, satisfying 0<E<30%.

[0216] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, wherein: include: A shell having an opening formed at an end portion along a first direction; Along the circumference of the opening, the housing includes a first wall, a corner area and a second wall connected in sequence; The first wall comprises a first main body portion and a first thickened portion arranged along the first direction, the first main body portion is farther away from the opening than the first thickened portion, and the maximum thickness of the first thickened portion is greater than the thickness of the first main body portion; The corner area has a second body portion and a second thickened portion arranged along the first direction, the second body portion is farther away from the opening than the second thickened portion, and the maximum thickness of the second thickened portion is greater than the thickness of the second body portion.

2. The battery cell according to claim 1, wherein: The maximum thickness of the second thickened portion is greater than the maximum thickness of the first thickened portion.

3. The battery cell according to claim 1 or 2, wherein: The maximum thickness of the second thickened portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the first thickened portion is t1, and the thickness of the first main body portion is t2, satisfying E≥F, E=(T1-T2) / T2, and F=(t1-t2) / t2.

4. The battery cell according to any one of claims 1 to 3, wherein: The maximum thickness of the second thickened portion is T1, and the thickness of the second main body portion is T2, satisfying 0<E<30%, and E=(T1-T2) / T2.

5. The battery cell according to claim 4, wherein: Satisfies, 0<E≤16.7%.

6. The battery cell according to any one of claims 1 to 5, wherein: Along the first direction, a distance from one end of the second thickened portion away from the opening to the opening is L1, satisfying 0<L1≤20 mm.

7. The battery cell according to any one of claims 1 to 6, wherein: Along the first direction, a distance from one end of the first thickened portion away from the opening to the opening is L2, satisfying 0<L2≤20 mm.

8. The battery cell according to any one of claims 1 to 7, wherein: An area of ​​an outer surface of the first wall is greater than an area of ​​an outer surface of the second wall.

9. The battery cell according to any one of claims 1 to 8, wherein: Along the second direction, the shell includes two first walls arranged opposite to each other, and along the third direction, the shell includes two second walls arranged opposite to each other, and the second direction, the third direction and the first direction are perpendicular to each other; The adjacent first walls and second walls are connected via the corresponding corner areas, and the first walls, the second walls and the corner areas together form the opening.

10. The battery cell according to any one of claims 1 to 9, wherein: The second wall has a third main body portion and a third thickened portion arranged along the first direction, the third main body portion is farther away from the opening than the third thickened portion, and the maximum thickness of the third thickened portion is greater than the thickness of the third main body portion.

11. The battery cell according to claim 10, wherein: The maximum thickness of the second thickened portion is greater than the maximum thickness of the third thickened portion.

12. The battery cell according to claim 10 or 11, wherein: The maximum thickness of the second thickened portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the third thickened portion is t3, and the thickness of the third main body portion is t4, satisfying E≥G, E=(T1-T2) / T2, G=(t3-t4) / t4.

13. The battery cell according to any one of claims 10 to 12, wherein: Along the first direction, a distance from one end of the third thickened portion away from the opening to the opening is L3, satisfying 0<L3≤20mm.

14. The battery cell according to any one of claims 10 to 13, wherein: The battery cell further includes an end cover, the end cover closing the opening; The third thickened portion includes a first section and a second section connected to each other, the first section, the second section and the third main body portion are distributed in sequence along the first direction, the maximum thickness of the second section is greater than the thickness of the third main body portion, the maximum thickness of the second section is greater than the maximum thickness of the first section, and the end cover is connected to the first section.

15. The battery cell according to claim 14, wherein: A first step surface is formed between the second section and the first section, and the end cover is overlapped on the first step surface.

16. The battery cell according to any one of claims 1 to 15, wherein: The battery cell further includes an end cover, the end cover closing the opening; The second thickened portion includes a third section and a fourth section that are connected to each other. The third section, the fourth section and the second main body are distributed in sequence along the first direction. The maximum thickness of the fourth section is greater than the thickness of the second main body. The maximum thickness of the fourth section is greater than the maximum thickness of the third section. The end cover is connected to the third section.

17. The battery cell according to claim 16, wherein: A second step surface is formed between the fourth section and the third section, and the end cover is overlapped on the second step surface.

18. The battery cell according to any one of claims 1 to 17, wherein: The battery cell also includes an end cover, which is welded to the second thickened portion to form a fusion zone. The average grain size of the second thickened portion other than the fusion zone is greater than the average grain size of the second main body portion, and the average grain size is the average grain size of the grains in the first direction.

19. The battery cell according to claim 18, wherein: On a cross section of the corner region parallel to the first direction, in a portion of the second thickened portion below the fusion zone, the number of grains in the width direction of the cross section is greater than or equal to 15.

20. The battery cell according to claim 18 or 19, wherein: The average grain size of the second thickened portion other than the fusion zone is in the range of 70 μm to 1200 μm; and / or, the average grain size of the second body portion is in the range of 30 μm to 1000 μm; And / or, the maximum wall thickness of the end cover is 0.25 mm-3 mm.

21. A battery, wherein: A battery cell comprising the battery cell according to any one of claims 1 to 20.

22. An energy storage device, wherein: A battery cell comprising the battery cell according to any one of claims 1 to 20.

23. An electrical device, wherein: A battery cell comprising the battery cell according to any one of claims 1 to 20.

Images