Battery cell, battery and electric device

Abstract

The single battery comprises an end cover, a shell and an electrode assembly, the end cover is provided with a first side surface and a second side surface which are opposite to each other, the end cover is provided with a mounting groove with a groove opening facing the second side surface, the shell is provided with a containing cavity and an opening communicated with the containing cavity, and the electrode assembly is arranged in the mounting groove. The position, close to the opening, of the shell is thinned and extends into the mounting groove to be connected with the end cover, and the electrode assembly is arranged in the containing cavity. Therefore, on one hand, the welding strength can be improved, the coping capacity of the welding area to fatigue stress, breathing effect and expansive force can be improved, the probability of cracking of welding seams can be reduced, and then the reliability and safety of the battery monomers are improved, and on the other hand, the attractiveness of the shell can be improved, the space occupation of the shell is reduced, and the service life of the shell is prolonged. And welding strength and energy density are both considered.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery monomer, a battery and an electrical device. Background Art

[0002] In the related art, during the production process of battery cells, it is necessary to weld the end cover and the shell (usually an aluminum shell).

[0003] However, during the cyclic charge and discharge process of the battery cell, there are fluctuations in the internal air pressure, and breathing fatigue stress will be generated in the weld area between the end cover and the shell. In addition, the expansion force of the battery cell will increase during long-term use, which will also increase the fatigue stress in the weld area, resulting in an increased risk of cracking in the weld of the battery cell and reduced working stability and reliability of the battery cell. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a battery cell, which has a higher structural strength and a lower risk of cracking, and can improve the stability and reliability of the battery cell.

[0005] The present application also proposes a battery having the above-mentioned battery cell.

[0006] The present application further proposes an electrical device using the above battery.

[0007] In a first aspect, the present application provides a battery cell, which includes: an end cap, a shell and an electrode assembly, the end cap having a first side surface and a second side surface opposite to each other, the end cap having a mounting groove with a notch opening toward the second side surface, the shell having a accommodating cavity and an opening connected to the accommodating cavity, the shell having a reduced thickness adjacent to the opening and extending into the mounting groove, connected to the end cap, and the electrode assembly being disposed in the accommodating cavity.

[0008] According to the battery cell of the embodiment of the present application, by providing a mounting groove and thinning the thickness of the portion of the shell extending into the mounting groove, the shell can be limited and self-locked on both sides of the portion of the shell extending into the mounting groove by the side walls of the mounting groove, which can improve the welding area's ability to cope with fatigue stress, breathing effect and expansion force, reduce the probability of cracking in the weld, and thereby improve the reliability and safety of the battery cell, and the portion of the shell with reduced thickness can further increase the welding area between the shell and the end cover to improve welding strength and reliability, and can keep the outer surface of the shell and the outer surface of the end cover flat, further improving the aesthetics of the battery cell.

[0009] According to some embodiments of the present application, the shell includes: a side plate and a bottom plate, the side plate is cylindrical, one end of the side plate is connected to the bottom plate, and the other end of the side plate defines an opening, the side plate includes a first plate portion and a second plate portion connected in sequence in a direction toward the opening, the second plate portion is thinner than the first plate portion, and at least a portion of the second plate portion extends into the mounting groove.

[0010] In the above technical solution, the second plate body extends into the mounting groove, and a step surface is defined between the second plate portion and the first plate portion, and the step surface and the second plate portion are both connected to the end cover to improve the connection stability and reliability. The formation of the step surface allows there to be no height difference or a smaller height difference between the side surface of the first plate portion and the side surface of the end cover (the first side surface and the second side surface are arranged opposite to each other in the first direction, and in the second direction, the surface of the end cover is the side surface of the end cover), so as to improve the flatness of the appearance of the battery cell and improve the aesthetics of the battery cell.

[0011] According to some embodiments of the present application, the thickness A of the side plate and the thickness B of the second plate portion satisfy: 0.33A≤B≤0.67A.

[0012] In the above technical solution, the thickness of the second plate portion can be made more reasonable, so as to avoid the second plate portion being too thin, which results in an unstable self-locking effect between the second plate portion and the mounting groove, and avoid the second plate portion being too thick, which results in an overly large mounting groove, and then results in the second plate being too small, so as to make the second plate thickness and the second plate portion thickness more reasonable, so as to achieve a better self-locking effect between the second plate portion and the end cover, better protection for the weld, and higher structural stability of the shell. According to some embodiments of the present application, the side panel includes a first side panel defining a large surface of the battery cell and a second side panel defining a small surface of the battery cell, the second plate portion includes a first sub-plate portion corresponding to the first side panel and a second sub-plate portion corresponding to the second side panel, the thickness of the first side panel is the same as or different from the thickness of the second side panel, the thickness of the first sub-plate portion is the same as or different from the thickness of the second sub-plate portion, and the thickness of the first sub-plate portion and the thickness of the second sub-plate portion both satisfy 0.33A≤B≤0.67A.

[0013] In the above technical solution, the thickness of the first sub-plate portion and the first side plate, and the thickness of the second sub-plate portion and the second side plate can be matched, and the welding stress of the first side plate portion and the end cover welding area, and the welding stress of the second plate portion and the end cover welding area can be more reasonable, thereby reducing the deformation of the shell during the welding process and improving the structural stability and reliability of the shell.

[0014] According to some embodiments of the present application, the end cover has a first plate and a second plate spaced apart in the circumferential direction of the end cover, the second plate is configured as an annular plate and is arranged around the first plate, and the portion of the shell extending into the mounting groove is located between the first plate and the second plate.

[0015] In the above technical solution, a mounting groove distributed along the circumference of the end cover is defined between the first plate and the second plate, and when the side plate and the end cover are assembled, the upper end of the side plate can be installed in the mounting groove, and the housing is assembled and positioned by the mounting groove, which can improve the assembly accuracy, and the side plate is embedded in the mounting groove, the inner side surface of the side plate is opposite to the first plate, the upper end surface of the side plate is opposite to the top wall of the mounting groove, and the outer side surface of the side plate is opposite to the second plate, which can increase the contact area between the side plate and the end cover, and the area of ​​the welding area is larger, which can increase the accommodation area, increase the penetration depth and the penetration width, so as to improve the welding strength. According to some embodiments of the present application, the second plate includes a first sub-plate corresponding to the first side plate and a second sub-plate corresponding to the second side plate, and the thickness of the first sub-plate and the second sub-plate are the same or different.

[0016] In the above technical scheme, in some embodiments, the first sub-plate and the second sub-plate have the same size, that is, the thickness of the second plate corresponding to the first side plate and the thickness of the second plate corresponding to the second side plate are consistent, which is convenient for processing, while in other embodiments, the sizes of the first sub-plate and the second sub-plate are different, and the sizes of the two can be set corresponding to the thickness of the first side plate and the second side plate. The thickness of the first side plate is smaller, corresponding to the smaller thickness of the first sub-plate, and the thickness of the second side plate is larger, corresponding to the larger thickness of the second sub-plate, so that the matching stability of the shell and the end cover is higher and the size is more reasonable.

[0017] According to some embodiments of the present application, the thickness of the first sub-board and the thickness of the second sub-board are both 0.2 mm to 2 mm.

[0018] In the above technical solution, the self-locking cooperation effect between the first side panel and the first sub-panel, and the self-locking cooperation effect between the second side panel and the second sub-panel are more stable, and the dimensions of the width edge and the length edge of the battery cell are more reasonable, occupying less space, which can improve the energy density of the battery.

[0019] According to some embodiments of the present application, the thickness of the first sub-board is 0.5 mm, and the thickness of the second sub-board is 1.0 mm.

[0020] In the above technical solution, the first side plate and the first sub-plate, and the second side plate and the second sub-plate can be better matched, and the self-locking effect of the first sub-plate on the first side plate and the self-locking effect of the second sub-plate on the second side plate can be more stable and reliable. At the same time, the space occupied by the end plate can be taken into account, so that the arrangement of multiple battery cells in the battery can be more compact to improve the energy density.

[0021] According to some embodiments of the present application, the difference between the thickness of the first sub-board portion and the slot width of the mounting slot is 0.05 mm to 0.2 mm, and the difference between the thickness of the second sub-board portion and the slot width of the mounting slot is 0.05 mm to 0.4 mm.

[0022] In the above technical solution, in the length direction of the shell, the groove width of the mounting groove is greater than the thickness of the first side plate, and in the width direction of the shell, the groove width of the mounting groove is greater than the thickness of the second side plate, so that the first side plate and the end cover, and the second side plate and the end cover are clearance-matched during assembly, which can reduce the difficulty of assembly.

[0023] More importantly, by limiting the above-mentioned range of values, the gap value between the first sub-plate and the end cover can be made more reasonable, as can the gap value between the second sub-plate and the end cover. Avoiding too small a gap value can reduce the difficulty of assembly, and avoiding too large a gap value can improve welding stability and reliability.

[0024] According to some embodiments of the present application, the difference between the thickness of the first sub-board portion and the slot width of the mounting slot is 0.1 mm, and the difference between the thickness of the second sub-board portion and the slot width of the mounting slot is 0.2 mm.

[0025] In the above technical solution, the gap between the first sub-plate portion with a smaller thickness and the mounting groove is smaller, and the gap between the second sub-plate portion with a larger thickness and the mounting groove is larger. Under the premise of making the assembly difficulty between the end cover and the side plate lower, the volume of the molten pool during welding of the thinner first sub-plate portion can be made smaller, and the volume of the molten pool during welding of the thicker second sub-plate portion can be made larger. This can not only improve the welding effect, but also improve the welding stress, reduce the deformation during the welding process of the shell and the end cover, and reduce the probability of weld cracking.

[0026] According to some embodiments of the present application, the length of the second plate portion is 0.2 mm to 2 mm.

[0027] In the above technical solution, the length of the second plate portion is made more reasonable, which can avoid the second plate portion being too short, resulting in limited limiting effect of the mounting groove on the side plate, ensuring the limiting reliability and stability of the mounting groove, and also avoid the second plate portion being too long, so as to take into account the thickness and structural strength of the end cover in the first direction, thereby reducing the processing difficulty of the end cover.

[0028] According to some embodiments of the present application, the length of the second plate portion is 0.5 mm.

[0029] In the above technical solution, the limiting effect of the installation groove and the structural strength and size requirements of the end cover can be taken into consideration.

[0030] According to some embodiments of the present application, the length of the second plate is less than or equal to the length of the first plate, and the first plate portion is in contact with the first plate.

[0031] In the above technical solution, in an embodiment where the first plate and the second plate are equal in size in the first direction, while self-locking of the end cover and the side plate can be achieved, the depth of penetration in the welding area is the thickness of the first side plate or the second side plate. In an embodiment where the second plate and the first plate are different in size in the first direction, the depth of penetration in the welding area is greater than the thickness of the first side plate or the second side plate, the welding is greater, the welding strength is higher, and the structural strength of the shell is higher.

[0032] According to some embodiments of the present application, a length difference between the first plate and the second plate is 0 mm to 1.5 mm.

[0033] In the above technical solution, the first plate and the second plate have a size difference, so that the second plate can overlap the step surface defined between the first plate portion and the second plate portion, thereby increasing the penetration depth, extending the length of the welding area, and improving the welding strength. At the same time, the outer side surface of the second plate is flush with the outer side surface of the first plate portion, which can also improve the aesthetics of the shell.

[0034] In a second aspect, the present application provides a battery, comprising: a battery cell according to the above embodiment.

[0035] In a third aspect, the present application provides an electrical device, including: the battery of the above embodiment.

[0036] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0038] Figure 1 is a schematic diagram of an electrical device according to an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of disassembly of a battery according to an embodiment of the present application;

[0040] Figure 3 is a schematic diagram of disassembling a battery cell according to an embodiment of the present application;

[0041] Figure 4 is a schematic diagram of a battery cell according to an embodiment of the present application;

[0042] Figure 5 is a schematic diagram of the cooperation between the end plate and the side plate according to an embodiment of the present application;

[0043] Figure 6 is a schematic diagram of the cooperation between the end cover and the housing at an angle according to an embodiment of the present application;

[0044] Figure 7 yes Figure 6 The middle circle shows a partial enlarged schematic diagram of the H region;

[0045] Figure 8 is a schematic diagram of the cooperation between the end cover and the housing at another angle according to an embodiment of the present application;

[0046] Fig. 9 yes Figure 8 The middle circle shows a partial enlarged schematic diagram of area I;

[0047] Fig.10 is a schematic diagram of a shell according to another embodiment of the present application.

[0048] Reference numerals:

[0049] end cover 10, first side surface 11, second side surface 12, first plate 20, second plate 30, first sub-plate 31, second sub-plate 32, mounting groove 13,

[0050] Shell 40, side plate 41, first plate portion 411, second plate portion 412, first sub-plate portion 4121, second sub-plate portion 4122, first side plate 41a, second side plate 41b, bottom plate 42, accommodating cavity 43,

[0051] The electrode assembly 50,

[0052] Battery cell 300, battery 400, power device 500, controller 600, motor 700, box 800,

[0053] Thickness A of the side panel, thickness B of the second panel portion, thickness C of the second panel, thickness C1 of the first sub-panel, thickness C2 of the second sub-panel, slot width D of the mounting slot, length E of the second panel portion, length F of the first panel, length G of the second panel, first direction X, second direction Y. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0056] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0057] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0059] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0060] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0061] In the description of the present invention, a first feature being “above” or “below” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact but are in contact with each other via another feature therebetween.

[0062] In the description of the present invention, a first feature “above”, “over” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0063] The term "plurality" used in the present application refers to two or more (including two).

[0064] At present, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power and hybrid solar power stations, but are also widely used in electric bicycles, electric motorcycles, electric car lights and electric transportation vehicles, as well as military equipment and aerospace and other fields. With the continuous expansion of battery application fields, its market demand is also constantly expanding.

[0065] The battery cell may be a secondary battery, which refers to a battery cell that can be continuously used by activating the active material by charging after the battery cell is discharged.

[0066] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present invention.

[0067] The battery mentioned in the embodiment of the present invention refers to a single physical module including one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in mixed connection through a busbar.

[0068] In some embodiments, a plurality of battery cells may be combined into a battery unit, that is, when there are a plurality of battery cells, the plurality of battery cells are arranged and fixed to form a battery unit.

[0069] In some embodiments, the battery includes a case and a battery cell, at least one battery cell or at least one battery unit is accommodated in the case, and the case has an accommodating space, and at least one battery cell or at least one battery unit is accommodated in the accommodating space.

[0070] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0071] In some embodiments, the battery or battery unit may be part of an energy storage system. The energy storage system may be an energy storage container, an energy storage cabinet, etc., in which the battery and the energy shutdown module are integrated.

[0072] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety performance of the battery must also be considered.

[0073] The technical solution described in the embodiment of the utility model is applicable to batteries and electrical devices using batteries.

[0074] The electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiment of the utility model does not impose any special restrictions on the above-mentioned electrical devices.

[0075] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0076] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of the vehicle provided by some embodiments of the utility model. The interior of the vehicle is provided with a battery 400, and the battery 400 can be arranged at the bottom, head or tail of the vehicle. The battery 400 can be used for power supply of the vehicle, for example, the battery 400 can be used as the operating power supply of the vehicle.

[0077] The vehicle may further include a controller 600 and a motor 700 . The controller 600 is used to control the battery 400 to supply power to the motor 700 . The motor 700 serves as a load, for example, to meet the power requirements for starting, navigating and driving the vehicle.

[0078] In some embodiments of the present invention, the battery 400 can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0079] Please refer to Figure 2 , Figure 2 The exploded view of the battery 400 provided in some embodiments of the present invention. The battery 400 includes a battery cell and a box 800, and the box 800 is used to accommodate the battery cell (ie, a battery module).

[0080] Among them, the box body 800 is a component for accommodating the battery unit. The box body 800 provides a placement space for multiple battery cells 300 in the battery unit. The box body 800 can adopt a variety of structures. In some embodiments, the box body 800 may include a tray and a box body 800, and the tray and the box body 800 cover each other to define a placement space for accommodating the battery cells 300. The tray and the box body 800 can be in a variety of shapes, such as a cuboid, a cylinder, etc. The tray can be a hollow structure with one side open, and the box body 800 can also be a hollow structure with one side open. The open side of the box body 800 covers the open side of the tray, so as to form a box body 800 with a placement space. It can also be that the tray is a hollow structure with one side open, and the box body 800 is a plate-like structure. The box body 800 covers the open side of the tray, so as to form a box body 800 with a placement space. As an example, the battery cell 300 may be a cylindrical battery cell 300 , a prismatic battery cell 300 , or a battery cell 300 of other shapes, and the present invention has no particular limitation.

[0081] In the battery 400, there can be one or more battery cells 300. If there are more than one battery cell 300, the multiple battery cells 300 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 300 are both connected in series and in parallel. Multiple battery cells 300 can be connected in series, in parallel, or in mixed connection to form a battery unit, and then the multiple battery units are connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 800. Alternatively, all battery cells 300 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by all battery cells 300 is accommodated in the box 800.

[0082] The battery cell 300 serves as the smallest energy unit of a battery unit or a battery 400. A battery unit or a battery 400 includes a plurality of battery cells 300. The battery cell 300 includes a shell 40, an end cover 10, and an electrode assembly 50 disposed in the shell 40. The shell 40 is welded to the end cover 10. The large surface of the battery cell 300 is defined by the width edge and the length edge of the battery cell 300, the small surface of the battery cell 300 is defined by the width edge and the height edge, and the end surface of the battery cell 300 is defined by the length edge and the width edge.

[0083] The battery cell 300 includes: a shell 40, an end cover 10 and an electrode assembly 50. The shell 40 may include a bottom plate 42 and a side plate 41. The side plate 41 is arranged around the bottom plate 42 and defines a receiving space with a mounting opening. The electrode assembly 50 and other functional components can be arranged in the receiving space. The end cover 10 covers the mounting opening of the shell 40 to isolate the internal environment of the battery cell 300 from the external environment. The shape of the end cover 10 is compatible with the shape of the shell 40. The end cover 10 can be supported by a material with a certain hardness and strength (such as aluminum alloy, carbon fiber plate), and the end cover 10 can effectively protect the safety and reliability of the internal components of the battery cell 300 during extrusion and collision.

[0084] In some embodiments, the end cap 10 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 300 reaches a threshold value. The material of the end cap 10 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating member may also be provided on the inner side of the end cap 10, and the insulating member may be used to isolate the electrical connection components in the housing 40 from the end cap 10 to reduce the risk of short circuit. Exemplarily, the insulating member may be plastic, rubber, etc.

[0085] The shell 40 is a component used to cooperate with the end cap 10 to form the internal environment of the battery cell 300, wherein the formed internal environment can be used to accommodate the electrode assembly 50, the electrolyte and other components. The shell 40 and the end cap 10 can be independent components, and a mounting port can be set on the shell 40, and the internal environment of the battery cell 300 is formed by covering the opening of the end cap 10 at the mounting port. The shell 40 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 40 can be determined according to the specific shape and size of the electrode assembly 50. The material of the shell 40 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0086] The electrode assembly 50 is a component in the battery cell 300 where electrochemical reactions occur. One or more electrode assemblies 50 may be included in the housing 40. The electrode assembly 50 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 50, and the parts of the positive and negative electrode sheets without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the main body or at both ends of the main body, respectively. During the charge and discharge process of the battery 400, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0087] In the prior art, during the production process of the battery cell 300, it is necessary to weld the end cap 10 and the shell 40. After the end cap 10 and the shell 40 are welded, during the cyclic charge and discharge process, there are pressure fluctuations inside the shell 40, which will cause breathing fatigue stress in the weld area. In addition, the expansion force of the battery cell 300 will gradually increase during long-term use, which will also increase the risk of weld cracking, resulting in a decrease in the voltage of the battery cell 300 and an inability to use normally, thereby reducing the working stability and reliability of the battery cell 300.

[0088] In view of this, the embodiment of the utility model provides a battery cell 300, by setting a mounting groove 13 on the second side surface 12 of the end cover 10, and making the second plate portion 412 of the side plate 41 extend into the mounting groove 13, on the one hand, self-locking can be achieved between the end cover 10 and the shell 40, which can reduce the influence of internal and external stresses on the weld, and can improve the effect of the welding area in coping with fatigue stress, breathing effect and expansion force, and reduce the risk of cracking. On the other hand, welding can be performed between the first plate 20 and the shell 40, the second plate 30 and the shell 40, and the end face of the side plate 41 of the shell 40 and the end cover 10. The area of ​​the welding area is larger, which can increase the molten pool area, increase the molten depth and molten width, and thus improve the welding strength.

[0089] Reference below Figure 3-Figure 10 A battery cell 300 , a battery cell 300 , a battery 400 , and an electric device 500 according to an embodiment of the present invention are described.

[0090] like Figure 3 and Figure 4 As shown, in a first aspect, the present application provides a battery cell 300 , including: an end cover 10 , an electrode assembly 50 and a shell 40 .

[0091] See also Figure 5 , Figure 7 and Fig. 9As shown, the end cover 10 has a first side surface 11 and a second side surface 12 arranged opposite to each other, the end cover 10 is provided with a mounting groove 13 with a notch opening toward the second side surface 12, the shell 40 has a accommodating cavity 43 and an opening connected to the accommodating cavity 43, the thickness of the shell 40 adjacent to the opening is thinned and extends into the mounting groove 13, connected to the end cover 10, and the electrode assembly 50 is arranged in the accommodating cavity 43.

[0092] Specifically, the portion of the shell 40 extending into the mounting groove 13 is connected to the end cover 10, such as by welding, and the portion of the shell 40 extending into the mounting groove 13 is constructed as a thickness-reduced portion to form a step surface through the portion extending into the mounting groove 13 and the portion located outside the mounting groove 13, and the step surface can increase the area of ​​the connection region between the shell 40 and the end cover 10.

[0093] According to the battery cell 300 of the embodiment of the present application, by providing the mounting groove 13 and thinning the thickness of the portion of the shell 40 extending into the mounting groove 13, the shell 40 can be limited and self-locked on both sides of the portion of the shell 40 extending into the mounting groove 13 by the side walls of the mounting groove 13, which can improve the ability of the welding area to cope with fatigue stress, breathing effect and expansion force, reduce the probability of cracking in the weld, and thereby improve the reliability and safety of the battery cell 300, and the portion of the shell 40 with the thinned thickness can further increase the welding area between the shell 40 and the end cover 10 to improve the welding strength and reliability, and can keep the outer surface of the shell 40 and the outer surface of the end cover 10 flat, further improving the aesthetics of the battery cell 300.

[0094] like Figure 5 As shown, according to some embodiments of the present application, the shell 40 includes: a side plate 41 and a bottom plate 42, the side plate 41 is cylindrical, one end of the side plate 41 is connected to the bottom plate 42, and the other end of the side plate 41 defines an opening, and the side plate 41 includes a first plate portion 411 and a second plate portion 412 which are sequentially connected in a direction toward the opening, the second plate portion 412 is thinner than the first plate portion 411, and at least a portion of the second plate portion 412 extends into the mounting groove 13.

[0095] Specifically, the second plate body 412 extends into the mounting groove 13, and a step surface is defined between the second plate portion 412 and the first plate portion 411. The step surface and the second plate portion 412 are both connected to the end cover 10 to improve the connection stability and reliability. The formation of the step surface allows there to be no height difference or a smaller height difference between the side surface of the first plate portion 411 and the side surface of the end cover 10 (the first side surface 11 and the second side surface 12 are arranged opposite to each other in the first direction, and in the second direction, the surface of the end cover 10 is the side surface of the end cover 10), so as to improve the flatness of the appearance of the battery cell 300 and improve the aesthetics of the battery cell 300.

[0096] According to some embodiments of the present application, the thickness C of the side plate 41 and the thickness B of the second plate portion 412 satisfy the following relationship: 0.33A≤B≤0.67A.

[0097] Exemplarily, the thickness of the second plate portion 412 is 0.33 times, 0.5 times, 0.67 times, etc., of the thickness of the side plate 41 (i.e., the thickness of the first plate portion 411). For example, if the first plate portion 411 is 10 mm thick, the thickness of the second plate portion 412 is in the range of 3.3 mm to 6.7 mm.

[0098] In this way, the thickness of the second plate portion 412 can be made more reasonable, avoiding the second plate portion 412 being too thin, resulting in unstable self-locking effect between the second plate portion 412 and the mounting groove 13, and avoiding the second plate portion 412 being too thick, resulting in the mounting groove 13 being too large, and then resulting in the second plate 30 being too small, so that the thickness of the second plate 30 and the thickness of the second plate portion 412 are more reasonable, thereby achieving better self-locking effect between the second plate portion 412 and the end cover 10, better protection of the weld, and higher structural stability of the battery cell 300.

[0099] like Figure 6 and Figure 8 As shown, according to some embodiments of the present application, the side plate 41 includes a first side plate 41a that defines a large surface of the battery cell 300 and a second side plate 41b that defines a small surface of the battery cell 300, the second plate portion 412 includes a first sub-plate portion 4121 corresponding to the first side plate 41a and a second sub-plate portion 4122 corresponding to the second side plate 41b, the thickness of the first side plate 41a is the same as or different from the thickness of the second side plate 41b, the thickness of the first sub-plate portion 4121 is the same as or different from the thickness of the second sub-plate portion 4122, and the thickness of the first sub-plate portion 4121 and the thickness of the second sub-plate portion 4122 both satisfy 0.33A≤B≤0.67A.

[0100] Specifically, the thickness of the first sub-plate portion 4121 may be B1, and the thickness of the first side plate 41a corresponding to the first sub-plate portion 4121 is A1, and 0.33A1≤B1≤0.67A1 is satisfied; the thickness of the second sub-plate portion 4122 may be B2, and the thickness of the second side plate 41b corresponding to the second sub-plate portion 4122 is A2, and 0.33A2≤B2≤0.67A2 is satisfied; and A1 and A2 may be equal or unequal, and the thicknesses of the corresponding first sub-plate portion 4121 and the second sub-plate portion 4122 may be the same or different.

[0101] In this way, the thickness of the first sub-plate portion 4121 and the first side plate 41a, and the thickness of the second sub-plate portion 4122 and the second side plate 41b can be matched, and the welding stress in the welding area between the first side plate 41a and the end cover 10, and the welding stress in the welding area between the second plate portion 412 and the end cover 10 can be more reasonable, thereby reducing the deformation of the battery cell 300 during the welding process and improving the structural stability and reliability of the battery cell 300.

[0102] According to some embodiments of the present application, the end cover 10 has a first plate 20 and a second plate 30 spaced apart in the circumferential direction of the end cover 10, the second plate 30 is constructed as an annular plate and is arranged around the first plate 20, and the portion of the shell 40 extending into the mounting groove 13 is located between the first plate 20 and the second plate 30.

[0103] Among them, the end cover 10 may include a cover body and a first plate 20 and a second plate 30 connected to the cover body, the first side surface 11 and the second side surface 12 are arranged back to back in a first direction, and the first plate 20 and the second plate 30 are spaced apart in a second direction perpendicular to the first direction, and define an installation groove 13, which is used to install the side plate 41 of the shell 40 of the battery cell 300.

[0104] The end cover 100 can be generally a plate structure, and the corresponding cover body and the first plate 20 define a cross-sectional profile with a convex cross-section, and the second plate 30 is connected to the cover body on the side facing the first side surface 11, the second plate 30 and the first plate 30 define a second side surface 12, and the second plate 30 surrounds the first plate 20 to form an installation groove 13.

[0105] It should be pointed out that the first direction can be the height direction (up and down direction, vertical direction) of the battery cell 300, that is, the X direction in the figure, and the corresponding second direction can be the length direction and width direction of the battery cell 300 (horizontal direction, corresponding to the left and right direction of the large surface of the battery cell 300, corresponding to the front and back direction of the end face of the battery cell 300), that is, the Y direction in the figure. In other words, the end cover 10 is assembled to the shell 40 from the height direction, and can be welded to the shell 40 in the left and right direction and the front and back direction respectively.

[0106] Among them, the first side surface 11 refers to the side surface of the end cover 10 away from the shell 40, and the second side surface 12 refers to the side surface of the end cover 10 opposite to the electrode assembly 50. The first side surface 11 is basically parallel to the second side surface 12, and the thickness of the shell 40 remains basically unchanged.

[0107] Specifically, a mounting groove 13 distributed along the circumference of the end cover 10 is defined between the first plate 20 and the second plate 30, and when the side plate 41 is assembled with the end cover 10, the upper end of the side plate 41 can be installed in the mounting groove 13, and the shell 40 is assembled and positioned by the mounting groove 13, which can improve the assembly accuracy. The side plate 41 is embedded in the mounting groove 13, and the inner side surface of the side plate 41 is opposite to the first plate 20, the upper end surface of the side plate 41 is opposite to the top wall of the mounting groove 13, and the outer side surface of the side plate 41 is opposite to the second plate 30, which can increase the contact area between the side plate 41 and the end cover 10, and the area of ​​the welding area is larger, which can increase the accommodating area, increase the fusion depth and fusion width, and improve the welding strength.

[0108] It can be understood that the side plate 41 is embedded in the installation groove 13, and the first plate 20 and the second plate 30 are located on both sides of the side plate 41 in the second direction. When the battery cell 300 is subjected to stress in the second direction, the end cover 10 has a limiting effect on the inward stress of the shell 40 and a weakening effect on the outward stress, so that the end cover 10 forms a self-locking effect on the shell 40, which can reduce the influence of internal and external stresses on the weld, improve the welding area's ability to cope with fatigue stress, breathing effect and expansion force, and reduce the risk of cracking in the weld.

[0109] Furthermore, the shell 40 has a side plate 41 , and in the first direction, the side plate 41 includes a first plate portion 411 and a second plate portion 412 connected in sequence, the thickness of the second plate portion 412 is smaller than that of the first plate portion 411 , and the second plate portion 412 extends into the mounting groove 13 .

[0110] Specifically, the first plate portion 411 and the second plate portion 412 are arranged in sequence in the first direction, the second plate portion 412 extends into the mounting groove 13, and the thickness of the first plate portion 411 is greater than the thickness of the second plate portion 412. Then, at least part of the second plate 30 can overlap with the first plate portion 411 in the first direction, so that the outer side surface of the end cover 10 can be flush with the outer side surface of the side plate 41 or the protruding size can be smaller, which can not only make the appearance of the battery cell 300 smoother and improve the aesthetics, but also improve the space occupancy of the battery cell 300 to increase the energy density of the battery cell 300.

[0111] In some embodiments, the inner side surfaces of the first plate portion 411 and the second plate portion 412 can be made flush, while the outer side surfaces form a step surface in a second direction perpendicular to the first direction. The lower surface of the end cover 10 can overlap the step surface. On the basis of the inner side surface of the side panel 41 and the first plate 20, the upper end surface of the side panel 41 and the top wall of the mounting groove 13, and the outer side surface of the side panel 41 and the second plate 30, the step surface and the lower surface of the end cover 10 are further increased to form a welding area. The welding area is larger, the welding strength can be higher, and the probability of weld cracking can be further reduced.

[0112] In summary, according to the battery cell 300 of the embodiment of the present application, on the one hand, the installation groove 13 is defined by the first plate 20 and the second plate 30, which can not only improve the welding strength, but also improve the ability of the welding area to cope with fatigue stress, breathing effect and expansion force, and reduce the probability of cracking in the weld, thereby improving the reliability and safety of the battery cell 300. On the other hand, the second plate portion 412 with a thickness less than the first plate portion 411 is extended into the installation groove 13, which can improve the aesthetics of the battery cell 300 and improve the space occupancy of the battery cell 300, while taking into account both welding strength and energy density.

[0113] Combination Figure 5-Figure 9 As shown, according to some embodiments of the present application, the second plate 30 includes a first sub-plate 31 corresponding to the first side plate 41a and a second sub-plate 32 corresponding to the second side plate 41b, and the thickness C1 of the first sub-plate 31 and the thickness C2 of the second sub-plate 32 are the same or different.

[0114] In other words, the thickness C1 of the first sub-plate 31 and the thickness C2 of the second sub-plate 32 may be the same or different in size.

[0115] In some embodiments, the first sub-plate 31 and the second sub-plate 32 have the same size, that is, the thickness of the second plate 20 corresponding to the first side plate 211 and the thickness of the second plate 20 corresponding to the second side plate 212 are consistent, which is convenient for processing. In other embodiments, the sizes of the first sub-plate 31 and the second sub-plate 32 are different. The sizes of the two can be set corresponding to the thickness of the first side plate 211 and the second side plate 212. The thickness of the first side plate 211 is smaller, and the corresponding thickness C1 of the first sub-plate 31 is smaller, and the thickness of the second side plate 212 is larger, and the corresponding thickness C2 of the second sub-plate 32 is larger, so that the matching stability of the shell 40 and the end cover 10 is higher and the size is more reasonable.

[0116] According to some embodiments of the present application, the thickness C1 of the first sub-plate 31 and the thickness C2 of the second sub-plate 32 are both 0.2 mm to 2 mm.

[0117] Specifically, the side panel 41 includes a first side panel 41a defining a length edge and a height edge, and a second side panel 41b defining a width edge and a height edge. The first sub-panel 31 is arranged corresponding to the first side panel 41a, and the second sub-panel 32 is arranged corresponding to the second side panel 41b. The thickness C1 of the first sub-panel 31 and the thickness C2 of the second sub-panel 32 are both in the range of 0.2 mm to 2 mm.

[0118] In this way, the self-locking cooperation effect between the first side plate 41a and the first sub-plate 31, and the self-locking cooperation effect between the second side plate 41b and the second sub-plate 32 are more stable, and the dimensions of the width edge and the length edge of the battery cell 300 are more reasonable, occupying less space, thereby improving the energy density of the battery 400.

[0119] Furthermore, the thickness C of the second plate 30 is 0.2 mm to 2 mm.

[0120] Exemplarily, the thickness C of the second plate 30 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, etc.

[0121] It should be noted that when the thickness C of the second plate 30 is less than 0.2 mm, the size of the second plate 30 is too small, and the second plate 30 has poor effects on weakening outward stress and limiting inward stress. When the size of the second plate 30 is too large, the peripheral edge of the end cover 10 will protrude too much from the side of the shell 40, aggravating the space occupation of the battery cell 300 and affecting the energy density. Within the range of 0.2 mm to 2 mm, both the space occupation and the self-locking effect can be taken into account.

[0122] Specifically, the side panel 41 includes a first side panel 41a defining a length edge and a height edge, and a second side panel 41b defining a width edge and a height edge. The first sub-panel 31 is arranged corresponding to the first side panel 41a, and the second sub-panel 32 is arranged corresponding to the second side panel 41b. The thickness C2 of the first sub-panel 31 and the second sub-panel 32 are both in the range of 0.2 mm to 2 mm.

[0123] In this way, the self-locking cooperation effect between the first side plate 41a and the first sub-plate 31, and the self-locking cooperation effect between the second side plate 41b and the second sub-plate 32 are more stable, and the dimensions of the width edge and the length edge of the battery cell 300 are more reasonable, occupying less space, thereby improving the energy density of the battery 400.

[0124] In addition, in some embodiments, the first sub-plate 31 and the second sub-plate 32 have the same size, that is, the thickness C of the second plate 30 corresponding to the first side plate 41a and the thickness C of the second plate 30 corresponding to the second side plate 41b are consistent, which is convenient for processing. In other embodiments, the sizes of the first sub-plate 31 and the second sub-plate 32 are different. The sizes of the two can be set corresponding to the thickness of the first side plate 41a and the second side plate 41b. The thickness of the first side plate 41a is smaller, and the corresponding thickness C1 of the first sub-plate 31 is smaller, and the thickness of the second side plate 41b is larger, and the corresponding thickness C2 of the second sub-plate 32 is larger, so that the matching stability with the end cover 10 is higher and the size is more reasonable.

[0125] Combination Figure 7 and Fig. 9 As shown, according to some embodiments of the present application, the thickness C1 of the first sub-plate 31 is 0.5 mm, and the thickness C2 of the second sub-plate 32 is 1.0 mm.

[0126] It should be pointed out that the thickness of the first side plate 41a and the second side plate 41b of the shell 40 can be different. Commonly, the thickness of the first side plate 41a defining the large surface of the battery cell 300 is less than the thickness of the second side plate 41b defining the end surface of the battery cell 300. The thickness C2 of the second sub-plate 32 corresponding to the second side plate 41b with a larger thickness is 1 mm, while the thickness C1 of the first sub-plate 31 corresponding to the first side plate 41a with a smaller thickness is 0.5 mm.

[0127] In this way, the first side plate 41a and the first sub-plate 31, and the second side plate 41b and the second sub-plate 32 can be better matched, and the self-locking effect of the first sub-plate 31 on the first side plate 41a, and the self-locking effect of the second sub-plate 32 on the second side plate 41b can be more stable and reliable. At the same time, the space occupied by the end plate can be taken into account, so that the arrangement of multiple battery cells 300 in the battery 400 can be more compact to improve the energy density.

[0128] like Figure 7 and Fig. 9 As shown, according to some embodiments of the present application, the difference between the thickness of the first sub-plate portion 4121 and the slot width D of the mounting slot 13 is 0.05mm-0.2mm, and the difference between the thickness of the second sub-plate portion 4122 and the slot width D of the mounting slot 13 is 0.05mm-0.4mm.

[0129] Exemplarily, the difference between the thickness of the first sub-plate portion 4121 and the slot width is 0.05mm, 0.1mm, 0.15mm, 0.2mm, etc., and the difference between the thickness of the second sub-plate portion 4122 and the slot width is 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, etc.

[0130] It should be pointed out that in the length direction of the shell 40, the groove width D of the mounting groove 13 is greater than the thickness of the first sub-plate portion 4121, and in the width direction of the shell 40, the groove width D of the mounting groove 13 is greater than the thickness of the second sub-plate portion 4122, so that the first sub-plate portion 4121 and the end cover 10, and the second sub-plate portion 4122 and the end cover 10 can be clearance-matched during the assembly process, which can reduce the difficulty of assembly.

[0131] More importantly, by limiting the above-mentioned range of values, the gap value between the first sub-plate portion 4121 and the end cover 10 can be made more reasonable, as can the gap value between the second sub-plate portion 4122 and the end cover 10. This can avoid the gap value being too small, thereby reducing the difficulty of assembly, and avoid the gap value being too large, thereby improving welding stability and reliability.

[0132] In some embodiments, the groove width of the installation groove 13 corresponding to the first sub-board portion 4121 area is consistent with the groove width of the installation groove 13 corresponding to the second sub-board portion 4122 area. In other embodiments, the groove width corresponding to the second sub-board portion 4122 area is greater than the groove width corresponding to the first sub-board portion 4121 area.

[0133] According to some embodiments of the present application, the difference between the thickness of the first sub-plate portion 4121 and the slot width D of the mounting slot 13 is 0.1 mm, and the difference between the thickness of the second sub-plate portion 4122 and the slot width D of the mounting slot 13 is 0.2 mm.

[0134] As a result, the gap between the first sub-plate portion 4121 with a smaller thickness and the mounting groove 13 is smaller, and the gap between the second sub-plate portion 4122 with a larger thickness and the mounting groove 13 is larger. Under the premise of making the assembly difficulty between the end cover 10 and the side plate 41 lower, the volume of the molten pool during welding of the thinner first sub-plate portion 4121 can be made smaller, and the volume of the molten pool during welding of the thicker second sub-plate portion 4122 can be made larger. This can not only improve the welding effect, but also improve the welding stress, reduce the deformation during the welding process of the shell 40 and the end cover 10, and reduce the probability of weld cracking.

[0135] See also Figure 5 , Figure 7 and Fig. 9 As shown, according to some embodiments of the present application, the length E of the second plate portion 412 is 0.2 mm to 2 mm.

[0136] Exemplarily, the dimension of the second plate portion 412 extending into the mounting groove 13 in the first direction may be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc.

[0137] In this way, the length E of the second plate portion 412 is more reasonable, which can prevent the second plate portion 412 from being too short, resulting in limited limiting effect of the mounting groove 13 on the side plate 41, ensuring the limiting reliability and stability of the mounting groove 13, and preventing the second plate portion 412 from being too long, so as to take into account the thickness and structural strength of the end cover 10 in the first direction, thereby reducing the processing difficulty of the end cover 10.

[0138] According to some embodiments of the present application, the length E of the second plate portion 412 is 0.5 mm.

[0139] It should be pointed out that the thickness of the end cover 10 is generally 2 mm to 3 mm, and a chamfer of about 0.5 mm is provided. In fact, in the first direction, the end cover 10 can set the effective height of the mounting groove 13 to be 1.5 mm to 2.5 mm, and based on the structural strength requirements of the end cover 10, the thickness of the end cover 10 needs to be set below 2 mm.

[0140] Furthermore, the present application limits the length of the second plate portion 412 to 0.5 mm, and the first plate 20 and the second plate 30 may have a height difference of about 0.5 mm in the first direction, which can take into account the limiting effect of the mounting groove 13 and the structural strength and size requirements of the end cover 10.

[0141] See also Figure 5 and Fig.10 As shown, according to some embodiments of the present application, the length of the second plate 30 is less than or equal to the length F of the first plate 20 , and the first plate portion 411 is in contact with the first plate 20 .

[0142] In some embodiments, the lengths G of the first plate 20 and the second plate 30 are equal. In other embodiments, the length F of the first plate 20 is greater than the length G of the second plate 30 .

[0143] It can be understood that in an embodiment where the first plate 20 and the second plate 30 are equal in size in the first direction, while self-locking of the end cover 10 and the side plate 41 can be achieved, the depth of penetration of the welding area is the thickness of the first side plate 41a or the second side plate 41b. In an embodiment where the second plate 30 and the first plate 20 are different in size in the first direction, the depth of penetration of the welding area is greater than the thickness of the first side plate 41a or the second side plate 41b, the welding is larger, the welding strength is higher, and the structural strength of the battery cell 300 is higher.

[0144] According to some embodiments of the present application, the difference between the length F of the first plate 20 and the length G of the second plate 30 is 0 mm to 1.5 mm.

[0145] Exemplarily, the length G difference between the first plate 20 and the second plate 30 is 0 mm, 0.5 mm, 1 mm, 1.5 mm, etc. The first plate 20 and the second plate 30 have a size difference, so that the second plate 30 can overlap on the step surface defined between the first plate portion 411 and the second plate portion 412, thereby increasing the penetration depth, extending the length of the welding area, and improving the welding strength. At the same time, the outer side surface of the second plate 30 is flush with the outer side surface of the first plate portion 411, which can also improve the aesthetics.

[0146] It should be pointed out that penetration welding can be used between the end cover 10 and the shell 40, and side welding can be used to connect the end cover 10 and the shell 40. The welding depth can exceed the wall thickness of the side plate 41. While the molten pool is larger, the molten depth can also be within a more easily controlled range, thereby improving the welding quality, so that the connection stability between the end cover 10 and the shell 40 is higher, the probability of cracking failure is lower, and the working stability and reliability of the battery cell 300 are higher.

[0147] In a second aspect, the present application provides a battery 400 , comprising: the battery cell 300 of the above embodiment.

[0148] In a third aspect, the present application provides an electrical device 500 , comprising: the battery 400 of the above embodiment.

[0149] Other structures and operations of the end cap 10 , the battery cell 300 , the battery 400 and the electrical device 500 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0150] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0151] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: An end cover (10) having a first side surface (11) and a second side surface (12) disposed opposite to each other, and the end cover (10) is provided with a mounting groove (13) whose notch is open toward the second side surface (12); A shell (40) having a receiving cavity (43) and an opening communicating with the receiving cavity (43); the shell (40) is thinned at a position adjacent to the opening and extends into the mounting groove (13), and is connected to the end cover (10); An electrode assembly (50) is arranged in the accommodating cavity (43).

2. The battery cell according to claim 1, characterized in that: The shell (40) comprises: a side plate (41) and a bottom plate (42); the side plate (41) is cylindrical; one end of the side plate (41) is connected to the bottom plate (42); the other end of the side plate (41) defines the opening; the side plate (41) comprises a first plate portion (411) and a second plate portion (412) which are sequentially connected in a direction toward the opening; the second plate portion (412) is thinner than the first plate portion (411), and at least a portion of the second plate portion (412) extends into the mounting groove (13).

3. The battery cell according to claim 2, characterized in that: The thickness A of the side plate (41) and the thickness B of the second plate portion (412) satisfy the following relationship: 0.33A≤B≤0.67A.

4. The battery cell according to claim 3, characterized in that: The side plate (41) comprises a first side plate (41a) defining a large surface of a battery cell (300) and a second side plate (41b) defining a small surface of the battery cell (300); the second plate portion (412) comprises a first sub-plate portion (4121) corresponding to the first side plate (41a) and a second sub-plate portion (4122) corresponding to the second side plate (41b); the thickness of the first side plate (41a) is the same as or different from the thickness of the second side plate (41b); the thickness of the first sub-plate portion (4121) is the same as or different from the thickness of the second sub-plate portion (4122); and the thickness of the first sub-plate portion (4121) and the thickness of the second sub-plate portion (4122) both satisfy 0.33A≤B≤0.67A.

5. The battery cell according to claim 4, characterized in that: The end cover (10) comprises a first plate (20) and a second plate (30) which are spaced apart in the circumferential direction of the end cover (10); the second plate (30) is constructed as an annular plate and is arranged around the first plate (20); the portion of the housing (40) extending into the mounting groove (13) is located between the first plate (20) and the second plate (30).

6. The battery cell according to claim 5, characterized in that: The second plate (30) comprises a first sub-plate (31) corresponding to the first side plate (41a) and a second sub-plate (32) corresponding to the second side plate (41b); the thickness of the first sub-plate (31) and the second sub-plate (32) are the same or different.

7. The battery cell according to claim 5, characterized in that: The thickness of the first sub-plate (31) and the thickness of the second sub-plate (32) are both 0.2 mm to 2 mm.

8. The battery cell according to claim 5, characterized in that: The thickness of the first sub-plate (31) is 0.5 mm, and the thickness of the second sub-plate (32) is 1.0 mm.

9. The battery cell according to claim 5, characterized in that: The difference between the thickness of the first sub-plate portion (4121) and the slot width of the mounting groove (13) is 0.05 mm to 0.2 mm, and the difference between the thickness of the second sub-plate portion (4122) and the slot width of the mounting groove (13) is 0.05 mm to 0.4 mm.

10. The battery cell according to claim 9, characterized in that: The difference between the thickness of the first sub-plate portion (4121) and the slot width of the mounting groove (13) is 0.1 mm, and the difference between the thickness of the second sub-plate portion (4122) and the slot width of the mounting groove (13) is 0.2 mm.

11. The battery cell according to any one of claims 2 to 10, characterized in that: The length of the second plate portion (412) is 0.2 mm to 2 mm.

12. The battery cell according to claim 11, characterized in that: The length of the second plate portion (412) is 0.5 mm.

13. The battery cell according to any one of claims 2 to 10, characterized in that: The length of the second plate (30) is less than or equal to the length of the first plate (20), and the first plate portion (411) is in contact with the first plate (20).

14. The battery cell according to claim 13, characterized in that: The difference between the length of the first plate (20) and the length of the second plate (30) is 0 mm to 1.5 mm.

15. A battery (400), characterized in that: include: The battery cell (300) according to any one of claims 1 to 14.

16. An electrical device (500), characterized in that: include: The battery (400) as claimed in claim 15.

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