Battery cell, battery, and electric device

Abstract

A battery cell (20), a battery (100), and an electric device. The battery cell (20) comprises: a housing assembly (21), which comprises a housing (211) and a cover plate (212), wherein the housing (211) has an opening (211a), the cover plate (212) covers the opening (211a), the cover plate (212) has a peripheral side surface (212a), the peripheral side surface (212a) and / or the housing (211) is provided with a groove (24), a connecting portion (25) for sealing the opening (211a) is formed between the housing (211) and the cover plate (212), and the connecting portion (25) is at least partially accommodated in the groove (24); an electrode terminal (22), the electrode terminal (22) being arranged on the housing (211) or the cover plate (212); and an electrode assembly (23), the electrode assembly (23) being arranged in the housing (211) and being electrically connected to the electrode terminal (22).

Description

Battery cells, batteries and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number: 202323130406.5 and application date of November 20, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

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

[0004] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. Batteries consist of a housing and multiple cells housed within it. As core components of new energy vehicles, batteries hold high standards for both safety and longevity. However, during the manufacturing process, reliability issues arise in the welding of the battery housings within the cells, impacting the overall reliability of the cells and severely affecting the battery's performance and service life.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell and the battery.

[0007] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a shell assembly, comprising a shell and a cover plate, the shell having an opening, the cover plate covering the opening, the cover plate having a peripheral side surface, the peripheral side surface and / or the shell having a groove, a connecting portion for sealing the opening being formed between the shell and the cover plate, the connecting portion being at least partially accommodated in the groove; an electrode terminal, the electrode terminal being disposed on the shell or the cover plate; an electrode assembly, the electrode assembly being disposed in the shell and electrically connected to the electrode terminal.

[0008] In the above technical solution, by providing grooves on the peripheral side of the cover plate and / or the shell, the grooves can, on the one hand, reduce the stamping tear zone area of ​​the shell and / or cover plate, reduce the impact of impurities in the stamping tear zone area on welding, and improve the welding quality and welding stability of the cover plate and shell. On the other hand, the grooves can accommodate the cast structure formed during the welding process, reduce the probability of excess height and flange formation at the weld after welding, and can also relieve the pressure of metal vapor formed by subsequent welding, which can further improve the welding quality and welding stability of the cover plate and shell. In other words, the above solution can improve the reliability of the shell assembly, thereby improving the reliability of the battery cell, improving the performance of the battery cell, and extending the service life of the battery cell.

[0009] In some embodiments of the present application, a bisecting surface is formed along the thickness of the cover plate, with the groove located on the side of the bisecting surface closer to the outside of the cover plate. In this technical solution, the groove is closer to the outside of the cover plate, which allows the connection formed between the cover plate and the shell to be adaptively closer to the outside of the cover plate. This helps reduce the depth of the gap between the cover plate and the shell near the outside, reduces the amount of dust, water, and other substances in the gap, and reduces the impact of dust, water, and other substances on the connection over time. This helps improve the connection reliability between the cover plate and the shell, and thus improves the reliability of the battery cell.

[0010] In some embodiments of the present application, the groove is an annular groove disposed along the circumference of the cover plate. In this technical solution, by configuring the groove as an annular groove disposed along the circumference of the cover plate, the stamped tear zone area can be uniformly removed from the circumference of the shell and / or cover plate. This also facilitates the removal of a larger volume of the stamped tear zone area, further reducing the impact of the stamped tear zone area on the weld between the shell and cover plate, and facilitating improved weld quality and stability between the shell and cover plate.

[0011] In some embodiments of the present application, the peripheral side surface includes at least one edge surface, each edge surface is provided with at least one groove; and / or the shell includes at least one inner side surface, each inner side surface is provided with at least one groove.

[0012] In the above technical solution, if at least one groove is provided on each edge of the peripheral side surface, each edge surface can be partially grooved while the remaining portion is ungrooved. This can reduce the area of ​​the stamped tear zone on the cover plate and also reduce the effect of the groove on the edge strength of the cover plate, thereby improving the connection strength between the cover plate and the shell. If at least one groove is provided on each inner side surface of the shell, the inner side surface of the shell can be partially grooved while the remaining portion is ungrooved. This can reduce the area of ​​the stamped tear zone on the shell and also reduce the effect of the groove on the edge strength of the shell, thereby improving the connection strength between the shell and the cover plate.

[0013] In some embodiments of the present application, the groove is provided on the peripheral side surface. In this technical solution, by providing the groove on the cover plate while not providing the groove on the shell, the welding quality and reliability between the cover plate and the shell can be improved by reducing the stamped tear zone area on the cover plate. While reducing the weld height and the flanging metal, it is also conducive to the lightweight design of the shell, that is, the shell wall thickness is made relatively small. Since the volume and size of the shell are larger than the cover plate, thinning the shell wall thickness is conducive to reducing the volume of the battery cell and improving the energy density of the battery cell.

[0014] In some embodiments of the present application, the groove is connected to the outer side of the cover plate along the thickness direction of the cover plate.

[0015] In the above technical solution, because the groove connects to the outside of the cover plate along its thickness, the groove has a notch located on the outside of the cover plate. This notch facilitates observation of the connection between the cover plate and the shell, facilitating the welding operation between the cover plate and the shell. Furthermore, because the groove connects to the outside of the cover plate, metal vapor can be directly discharged to the outside during welding of the cover plate and the shell, facilitating smooth pressure relief of the metal vapor. Furthermore, because the connection is at least partially formed within the groove, the probability of a narrow gap forming between the outer edge of the cover plate and the shell after welding the cover plate and the shell is relatively low, and impurities such as dust and water stains are less likely to accumulate within the groove, thereby improving the reliability of the connection between the cover plate and the shell.

[0016] In some embodiments of the present application, the cover plate has an extension portion protruding from the peripheral side surface, the extension portion has a first surface close to the inner side of the cover plate, and the groove has a second surface away from the inner side of the cover plate, and the second surface is flush with the first surface.

[0017] In the above technical solution, the cover plate has an extension protruding from the peripheral side surface, allowing the cover plate to form a T-shaped structure. When the cover plate and the housing are mated, the extension abuts against the end surface of the housing, covering and sealing the gap between the peripheral side surface and the inner side surface of the housing, thereby reducing the chance of impurities such as dust and water stains from the external environment entering between the peripheral side surface and the inner side surface of the housing. The second surface of the groove is flush with the first surface of the extension, allowing metal vapor to flow to the outside along the second and first surfaces during welding of the cover plate and the housing, facilitating smooth pressure release of the metal vapor.

[0018] In some embodiments of the present application, the housing is provided with a relief recess, which is located on the outside of the housing and opposite the groove. In the above technical solution, when the housing and cover plate are welded, the outside of the housing forms a loose cast structure under the action of high temperature. Therefore, by adopting a structure in which the relief recess is provided in the housing, the relief recess can accommodate at least a portion of the cast structure, reducing the probability of the cast structure protruding from the outer side of the housing after cooling. This helps reduce the probability of weld excess height and flanging metal, and can improve the welding stability and quality of the housing and cover plate.

[0019] In some embodiments of the present application, the shell has a third surface facing the peripheral side surface, the air-avoiding recess has an air-avoiding surface, the air-avoiding surface is connected to the third surface, and the distance between the air-avoiding surface and the third surface gradually increases in the direction from the inside to the outside of the cover.

[0020] In the above technical solution, by setting the air avoidance recess to have an air avoidance surface, the distance between the air avoidance surface and the third surface of the shell gradually increases in the direction from the inside to the outside of the cover plate, and the air avoidance recess is constructed as an inclined surface on the shell, which is conducive to reducing the processing difficulty of the air avoidance recess, and the air avoidance surface can adapt to the distribution of the cast structure during the welding of the shell, which can reduce the probability of insufficient strength of the shell due to the inability to cover and fill the air avoidance surface.

[0021] In some embodiments of the present application, the connecting portion has a depth direction and a width direction. In the depth direction, the size of the groove is D1, and in the width direction, the size of the groove is W1, wherein the thickness of the cover plate is T1, W1 = (0.5 ~ 1.2) T1, D1 = (0.5 ~ 1.0) T1.

[0022] In the above technical solution, by setting the dimensions D1 and W1 of the groove and the thickness T1 of the cover plate to W1 in the range of 0.5T1 to 1.2T1 and D1 in the range of 0.5T1 to 1.0T1, the groove width and groove depth of the groove can be within an appropriate range, so that the volume of the stamped tear band removed from the cover plate is more appropriate, the effect of reducing the influence of impurities in the stamped tear band area on welding is better, the effect of relieving the pressure of metal vapor is also better, and the effect of improving the welding excess height and the flanging metal is also better.

[0023] In a second aspect, an embodiment of the present application further provides a battery, comprising the battery cell described above.

[0024] In the above technical solution, by providing grooves on the shell and / or cover plate of the battery cell, the stamping tear zone area on the shell and / or cover plate can be reduced, and the probability of excess height and flange formation at the weld after welding can be reduced. It can also relieve the pressure of metal vapor formed by subsequent welding, which is beneficial to improving the welding quality and welding stability of the cover plate and the shell, thereby improving the reliability of the battery cell.

[0025] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the aforementioned battery cell or the aforementioned battery.

[0026] In the above technical solution, by providing grooves on the shell and / or cover of the battery cell or battery, the stamped tear zone area on the shell and / or cover can be reduced, the probability of excess height and flange formation at the weld after welding is reduced, and the pressure of metal vapor formed by subsequent welding is released, which is beneficial to improving the reliability of the battery cell or battery, and thus beneficial to improving the reliability of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0029] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0030] FIG3 is a schematic diagram of the internal structure of a battery cell provided in some embodiments of the present application;

[0031] FIG4 is a schematic structural diagram of a cover plate provided in some embodiments of the present application;

[0032] FIG5 is a partial enlarged schematic diagram of FIG3;

[0033] FIG6 is a schematic diagram of the internal structure of a battery cell provided in some other embodiments of the present application;

[0034] FIG7 is a schematic structural diagram of a cover plate provided in some other embodiments of the present application;

[0035] FIG8 is a partially enlarged schematic diagram of FIG6 .

[0036] Icons: 1000, vehicle; 100, battery; 10, casing; 11, first casing body; 12, second casing body; 20, battery cell; 21, casing assembly; 211, casing; 211a, opening; 211b, third side; 2111, air-avoiding recess; 2111a, air-avoiding surface; 212, cover; 212a, peripheral side; 2121, extension; 2121a, first surface; 22, electrode terminal; 23, electrode assembly; 24, groove; 24a, second surface; 25, connecting portion; 26, bisecting surface; 200, controller; 300, motor; X, first direction; Y, second direction. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only 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 drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" 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-secondary relationship.

[0039] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the 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.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0041] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0042] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0043] The term "plurality" used in this application refers to two or more (including two).

[0044] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0045] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or battery pack. A battery generally includes a casing that encloses one or more battery cells or multiple battery modules. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0046] A battery cell includes a shell, an electrode assembly, and an electrolyte. The shell is used to hold the electrode assembly and the electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet consists of 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. The negative current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. To ensure that high currents can pass without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together.

[0047] The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0048] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. A battery consists of a housing and multiple cells housed within it. As a core component in new energy vehicles, batteries have high requirements for both safety and cycle life.

[0049] In a typical battery cell, the housing assembly consists of a shell and a cover plate. These components are typically formed through multiple stamping processes. During the stamping process, these components can develop tear zones. These zones are prone to contamination with impurities such as metal debris and oil. These impurities can cause defects such as pores and cracks during the welding and assembly of the shell and cover plate, increasing production costs. Furthermore, during welding, the dense forged structure of the shell and cover plate remelts, cools, and crystallizes, transforming into a looser cast structure. This means the welded structure formed after welding the shell and cover plate has a larger volume per unit mass, resulting in excess height and flanged welds. Currently, battery cell manufacturing uses roller pressing to improve flanged edges. However, for thin aluminum shells, excessive roller pressing can lead to excessively thin shells, which can cause leakage at the end and compromise battery cell reliability. Failure to perform roller pressing can also lead to wear and tear of the cell's blue film during service, resulting in insulation failure and similarly impacting battery cell reliability.

[0050] Based on the above considerations, in order to solve the defects such as air holes and explosion points that occur during the welding of the shell and cover plate during the manufacturing process of battery cells, as well as the excess height and flange phenomenon after welding, the inventors designed a battery cell, including a shell assembly, electrode terminals, and an electrode assembly. The shell assembly includes a shell and a cover plate. The shell has an opening, and the cover plate is arranged to cover the opening. The cover plate has a peripheral side surface, and the peripheral side surface and / or the shell are provided with a groove. A connecting portion for sealing the opening is formed between the shell and the cover plate, and the connecting portion is at least partially accommodated in the groove. The electrode terminal is provided on the shell or the cover plate. The electrode assembly is provided in the shell and is electrically connected to the electrode terminal.

[0051] In a battery cell of this structure, a groove is provided on the peripheral side of the cover plate and / or the shell, and a connection portion for sealing the opening is formed between the shell and the cover plate. The connection portion is at least partially accommodated in the groove. The groove can reduce the volume of the stamped tear zone area of ​​the shell and / or the cover plate. On the one hand, this structure can reduce impurities such as metal debris and oil stains during the welding process of the shell and the cover plate, and reduce the probability of defects such as pores and explosion points during the welding process. On the other hand, the groove can accommodate the cast structure formed during the welding process, alleviate the problem of excess height and flange formed at the weld after welding, or reduce the probability of excess height and flange formed at the weld after welding, and can also provide an effective metal vapor pressure relief groove for subsequent welding, which is beneficial to improving welding stability. In other words, the adoption of the above scheme is beneficial to improving the reliability of the shell assembly, thereby improving the reliability of the battery cell, improving the performance of the battery cell, and extending the service life of the battery cell.

[0052] The battery disclosed in the embodiments of the present application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical device.

[0053] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include 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 spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0054] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0055] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0056] In some embodiments of the present application, the battery 100 can 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.

[0057] Please refer to Figure 2, which is an exploded view of the structure of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a plurality of battery cells 20, which are intended to be accommodated within the housing 10. The housing 10 is used to provide an assembly space for the battery cells 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12, which cover each other and together define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure, with the first housing body 11 covering the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define an assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, with the open side of the first housing body 11 covering the open side of the second housing body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0058] In the battery 100, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 can be constructed by first connecting the multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then connected in series, in parallel, or in a hybrid configuration to form a single structure and housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0059] Referring to FIG. 2 , in some embodiments of the present application, a battery 100 may include multiple rows of battery cells 20 arranged along the length of the housing 10 , with each row of battery cells 20 including multiple battery cells 20 arranged along the width of the housing 10 . Alternatively, multiple rows of battery cells 20 may be arranged along the width of the housing 10 , with each row of battery cells 20 including multiple battery cells 20 arranged along the length of the housing 10 .

[0060] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be cylindrical, flat, rectangular, or in other shapes. For example, in FIG3 , the battery cell 20 is in the shape of a rectangular parallelepiped.

[0061] According to some embodiments of the present application, referring to FIG3 , FIG3 provides a battery cell 20 according to an embodiment of the present application, including: a shell assembly 21, an electrode terminal 22 and an electrode assembly 23, the shell assembly 21 includes a shell 211 and a cover plate 212, the shell 211 has an opening 211a, the cover plate 212 covers the opening 211a, the cover plate 212 has a peripheral side surface 212a, the peripheral side surface 212a and / or the shell 211 are provided with a groove 24, a connecting portion 25 for sealing the opening 211a is formed between the shell 211 and the cover plate 212, and the connecting portion 25 is at least partially accommodated in the groove 24; the electrode terminal 22 is provided on the shell 211 or the cover plate 212; the electrode assembly 23 is provided in the shell 211 and is electrically connected to the electrode terminal 22.

[0062] The housing 211 is used to accommodate the electrode assembly 23 and the electrolyte, and the cover plate 212 is used to cover the opening 211a of the housing 211 to seal the housing 211. Optionally, the housing 211 can be, but is not limited to, an aluminum housing or a steel housing.

[0063] The electrode terminal 22 may be a component used to electrically connect to an external conductor or to one electrode of another adjacent battery cell 20 in the battery pack. Specifically, the electrode terminal 22 can be understood as a terminal post. There may be at least two electrode terminals 22, at least one of which is a positive terminal and at least one is a negative terminal, for connecting to the positive and negative electrodes of an external power supply. The electrode assembly 23 is described above and will not be further elaborated here.

[0064] Because the housing 211 and cover plate 212 are typically formed through multiple stamping processes, tear zones may form on the housing 211 and cover plate 212 during the stamping process. The tear zone of the cover plate 212 is concentrated on the peripheral side surface 212a, while the tear zone of the housing 211 is concentrated on the end near the opening 211a. In the battery cell 20 with the aforementioned structure, the provision of grooves 24 on the cover plate 212 and / or the housing 211 can reduce the tear zone area.

[0065] Specifically, the groove 24 can be provided on the area of ​​the peripheral side surface 212a for forming the connection portion 25 with the shell 211. Through this solution, the tearing band area of ​​the cover plate 212 can be reduced; or, the groove 24 is provided on the area of ​​the shell 211 for forming the connection portion 25 with the cover plate 212. Through this solution, the tearing band area of ​​the shell 211 can be reduced; or, the groove 24 is provided on both the area where the shell 211 and the peripheral side surface 212a form the connection portion 25. Through this solution, the tearing band area of ​​the cover plate 212 and the tearing band area of ​​the shell 211 can be reduced.

[0066] The connection portion 25 may refer to a joint portion formed by welding the peripheral side surface 212a of the cover plate 212 and the housing 211. The connection portion 25 may be partially accommodated in the groove 24, or the connection portion 25 may be fully accommodated in the groove 24.

[0067] It can be understood that the groove 24 can reduce the stamping tear zone area of ​​the shell 211 and / or the cover plate 212. When the cover plate 212 and the shell 211 are welded, the groove 24 can reduce impurities such as metal debris and oil stains during the welding process, reduce the probability of defects such as pores and explosion points during the welding process, and improve the welding quality of the cover plate 212 and the shell 211.

[0068] Secondly, the groove 24 also has a storage space. Since the dense forging structure during the welding process of the cover plate 212 and the shell 211 is melted and cooled to form a loose cast structure, this cast structure will produce excess flanging metal. In this application, the flanging metal formed by welding can be partially or completely located within the groove 24, reducing the probability of the flanging metal protruding from the cover plate 212 or the shell 211, thereby alleviating the problem of excess height and flanging metal after welding. Metal vapor will be generated during the welding process of the cover plate 212 and the shell 211. The groove 24 can serve as a pressure relief groove for relieving the pressure of the metal vapor, which can increase the stability of the weld pool and improve the welding stability of the cover plate 212 and the shell 211.

[0069] In the above technical solution, by providing a groove 24 on the peripheral side surface 212a of the cover plate 212 and / or the shell 211, the groove 24 can, on the one hand, reduce the stamping tear zone area of ​​the shell 211 and / or the cover plate 212, reduce the influence of impurities in the stamping tear zone area on welding, and improve the welding quality and welding stability of the cover plate 212 and the shell 211. On the other hand, the groove 24 can accommodate the cast structure formed during the welding process, reduce the probability of excess height and flange formation at the weld after welding, and can also relieve the pressure of the metal vapor formed by subsequent welding, which can further improve the welding quality and welding stability of the cover plate 212 and the shell 211. In other words, the above solution can improve the reliability of the shell assembly 21, thereby improving the reliability of the battery cell 20, as well as improving the performance of the battery cell 20 and extending the service life of the battery cell 20.

[0070] In some embodiments of the present application, referring to FIG. 4 , a bisecting surface 26 is formed in the thickness direction of the cover plate 212 to divide the cover plate 212 into equal parts, and the groove 24 is located on a side of the bisecting surface 26 close to the outside of the cover plate 212 .

[0071] The “thickness direction of the cover plate 212 ” may refer to the second direction Y in FIG. 4 .

[0072] In the above technical solution, the groove 24 is closer to the outside of the cover plate 212, so that the connection part 25 formed between the cover plate 212 and the shell 211 can be adaptively closer to the outside of the cover plate 212, which is beneficial to reducing the depth of the gap between the cover plate 212 and the shell 211 near the outside, thereby reducing the content of dust, water and other substances in the gap, reducing the impact of dust, water and other substances on the connection part 25 after a long time, and helping to improve the connection reliability between the cover plate 212 and the shell 211, thereby improving the reliability of the battery cell 20.

[0073] In some embodiments of the present application, the groove 24 is an annular groove provided along the circumference of the cover plate 212 .

[0074] When the shell 211 is provided with a groove 24, the groove 24 on the shell 211 is an annular groove arranged along the circumference of the cover plate 212, that is, the groove 24 is arranged around the shell 211; when the cover plate 212 is provided with a groove 24, the groove 24 on the peripheral side surface 212a is an annular groove arranged along the circumference of the cover plate 212, that is, the groove 24 is arranged around the cover plate 212.

[0075] Optionally, the cross section of the annular groove in the thickness direction of the cover plate 212 may be, but not limited to, rectangular, semicircular, arc-shaped, etc. For example, referring to FIG3 to FIG8 , the cross section of the annular groove is rectangular.

[0076] In the groove 24 of the above structure, on the one hand, the groove 24 is an annular groove, which can evenly reduce the stamping tear band area in the circumferential direction of the shell 211 and / or the cover plate 212, so that the connection part 25 between the shell 211 and the cover plate 212 is more consistent in the circumferential direction, which can improve the welding quality and welding stability of the shell 211 and the cover plate 212. Secondly, the groove 24 is an annular groove, which is also conducive to removing more volume of the stamping tear band area on the shell 211 and / or the cover plate 212, reducing the impact of impurities in the stamping tear band area on the welding between the shell 211 and the cover plate 212, and helping to improve the welding quality and welding stability. On the other hand, the groove 24 is an annular groove, which is relatively simple to process on the shell 211 and / or the cover plate 212, and can reduce the forming steps of the groove 24, thereby saving work time and improving work efficiency.

[0077] In the above technical solution, by setting the groove 24 as an annular groove arranged along the circumference of the cover plate 212, the stamped tear band area can be evenly removed from the circumference of the shell 211 and / or the cover plate 212, which is also beneficial to remove a larger volume of the stamped tear band area, further reducing the influence of the stamped tear band area on the welding of the shell 211 and the cover plate 212, and is beneficial to improving the welding quality and welding stability of the shell 211 and the cover plate 212.

[0078] In some embodiments of the present application, the peripheral side surface 212a includes at least one edge surface, each edge surface is provided with at least one groove 24; and / or, the shell 211 includes at least one inner side surface, each inner side surface is provided with at least one groove 24.

[0079] The housing 211 may be a polygonal shell. For example, the housing 211 may be, but is not limited to, a triangular shell, a quadrilateral shell, a pentagonal shell, etc., and each side of the housing 211 corresponds to an inner side surface. Correspondingly, the shape of the cover 212 is the same as that of the housing 211. The cover 212 may be, but is not limited to, a triangular, quadrilateral, or pentagonal shell, etc., and the number of facets on the peripheral side surface 212a is equal to the number of inner side surfaces of the housing 211. Exemplarily, the housing 211 is a quadrilateral shell, and the housing 211 includes four inner side surfaces, while the peripheral side surface 212a includes four facets.

[0080] When the groove 24 is provided on the peripheral side surface 212a, at least one groove 24 is provided on each edge surface of the peripheral side surface 212a, that is, one or more grooves 24 can be provided on each edge surface. In this way, on the one hand, the groove 24 can remove a part of the stamped tear band area on the peripheral side surface 212a, reducing the influence of the stamped tear band area of ​​the cover plate 212 on welding. On the other hand, the proportion of the groove 24 on the peripheral side surface 212a will not be too large, that is, part of the peripheral side surface 212a is not grooved, which is beneficial to reduce the influence of the groove on the peripheral side strength of the cover plate 212, and improve the connection strength between the cover plate 212 and the shell 211.

[0081] When the shell 211 is provided with a groove 24, each inner side surface is provided with at least one groove 24, that is, each inner side surface can be provided with one or more grooves 24. In this way, on the one hand, the groove 24 can remove a part of the stamped tear band area on the shell 211, reducing the influence of the stamped tear band area of ​​the shell 211 on welding. On the other hand, the proportion of the groove 24 on the shell 211 will not be too large, that is, part of the inner side surface of the shell 211 is not grooved, which is beneficial to reduce the influence of the groove on the peripheral strength of the shell 211 and improve the connection strength between the shell 211 and the cover plate 212.

[0082] When grooves 24 are provided on both the peripheral side surface 212a and the housing 211, each edge face of the peripheral side surface 212a is provided with at least one groove 24, and each inner side face is provided with at least one groove 24. In this manner, the grooves 24 can remove a portion of the punched tear zone area on the housing 211 and the cover plate 212, respectively, while also reducing the effect of the grooves on the strength of the housing 211 and the cover plate 212, thereby improving the connection strength between the housing 211 and the cover plate 212.

[0083] In the above technical solution, if at least one groove 24 is provided on each edge face of the peripheral side surface 212a, each edge face can be partially grooved, while the remaining portion is not grooved. This can reduce the area of ​​the punched tear zone on the cover plate 212 and also reduce the effect of the groove 24 on the edge strength of the cover plate 212, thereby improving the connection strength between the cover plate 212 and the housing 211. If at least one groove 24 is provided on each inner side face of the housing 211, the inner side face of the housing 211 can be partially grooved, while the remaining portion is not grooved. This can reduce the area of ​​the punched tear zone on the housing 211 and also reduce the effect of the groove 24 on the edge strength of the housing 211, thereby improving the connection strength between the housing 211 and the cover plate 212.

[0084] In some embodiments of the present application, referring to FIG. 3 , FIG. 5 , FIG. 6 and FIG. 8 , the groove 24 is provided on the peripheral side surface 212 a .

[0085] It can be understood that the groove 24 is provided on the peripheral side surface 212a of the cover plate 212, while the inner side surface of the housing 211 is not grooved. The groove 24 can be an annular groove provided on the peripheral side surface 212a, or one or more grooves 24 can be provided on each edge surface of the peripheral side surface 212a.

[0086] In the above technical solution, by providing a groove 24 on the cover plate 212 and not slotting the shell 211, the welding quality and welding reliability between the cover plate 212 and the shell 211 can be improved by reducing the stamped tear band area on the cover plate 212. While reducing the welding excess height and flanging metal, it is beneficial to the lightweight design of the shell 211, that is, the wall thickness of the shell 211 is made relatively small. Since the volume and size of the shell 211 are larger than those of the cover plate 212, thinning the wall thickness of the shell 211 is beneficial to reducing the volume of the battery cell 20 and improving the energy density of the battery cell 20.

[0087] In some embodiments of the present application, referring to Figures 3 to 5 , the groove 24 is connected to the outer side of the cover plate 212 along the thickness direction of the cover plate 212. It can be understood that the groove 24 has two notches, one of which is located on the peripheral side surface 212a and the other is located on the outer side surface of the cover plate 212.

[0088] In the above technical solution, since the groove 24 is connected to the outside of the cover plate 212 along the thickness direction of the cover plate 212, the groove 24 has a notch located on the outside of the cover plate 212. The notch facilitates observation of the connection portion 25 between the cover plate 212 and the shell 211, which is beneficial to the welding operation between the cover plate 212 and the shell 211. Moreover, since the groove 24 is connected to the outside of the cover plate 212, the metal vapor can be directly discharged to the outside when the cover plate 212 and the shell 211 are welded, which is beneficial to the smooth pressure relief of the metal vapor. Secondly, since the connection portion 25 is at least partially formed in the groove 24, when the cover plate 212 and the shell 211 are welded, the probability of a narrow gap between the outer edge of the cover plate 212 and the shell 211 is relatively low, and impurities such as dust or water stains are not easily accumulated in the groove 24, which is beneficial to improving the connection reliability between the cover plate 212 and the shell 211.

[0089] In some embodiments of the present application, referring to Figures 6 to 8, the cover plate 212 has an extension portion 2121 protruding from the peripheral side surface 212a, the extension portion 2121 has a first surface 2121a close to the inner side of the cover plate 212, and the groove 24 has a second surface 24a away from the inner side of the cover plate 212, and the second surface 24a is flush with the first surface 2121a.

[0090] In the above technical solution, by having an extension portion 2121 protruding from the peripheral side surface 212a of the cover plate 212, the cover plate 212 can be formed into a T-shaped structure. When the cover plate 212 and the housing 211 are mated, the extension portion 2121 can abut against the end surface of the housing 211, thereby covering and sealing the gap between the peripheral side surface 212a and the inner side surface of the housing 211, thereby reducing the chance of impurities such as dust and water stains from the external environment entering between the peripheral side surface 212a and the inner side surface of the housing 211. The second surface 24a of the groove 24 is flush with the first surface 2121a of the extension portion 2121. This allows metal vapor to flow to the outside along the second surface 24a and the first surface 2121a during welding of the cover plate 212 and the housing 211, facilitating smooth pressure release of the metal vapor.

[0091] In some embodiments of the present application, referring to FIG. 8 , the housing 211 is provided with a space-avoiding recess 2111 , which is located on the outside of the housing 211 and is arranged opposite to the groove 24 .

[0092] The air-avoiding recess 2111 may refer to a recessed area on the outer side of the housing 211 and directly opposite to the groove 24. Specifically, the air-avoiding recess 2111 may be, but is not limited to, a groove and a chamfer.

[0093] In the above technical solution, when the shell 211 and the cover plate 212 are welded, a loose cast structure will be formed on the outer side of the shell 211 under the action of high temperature. Therefore, by adopting the structure of setting the air-avoiding recess 2111 in the shell 211, the air-avoiding recess 2111 can accommodate at least part of the cast structure, reducing the probability of the cast structure protruding from the outer side of the shell 211 after cooling, which is beneficial to reducing the probability of welding excess height and flanging metal, and can improve the welding stability of the shell 211 and the cover plate 212, and improve the welding quality.

[0094] In some embodiments of the present application, referring to Figure 8, the shell 211 has a third surface 211b facing the peripheral side surface 212a, the air-avoiding recess 2111 has an air-avoiding surface 2111a, the air-avoiding surface 2111a is connected to the third surface 211b, and the distance between the air-avoiding surface 2111a and the third surface 211b gradually increases in the direction from the inside to the outside of the cover plate 212.

[0095] It can be understood that when the shell 211 and the cover plate 212 are welded, the as-cast structure formed on the outer surface of the shell 211 due to the high temperature will cover the gap surface 2111a, filling the missing portion of the shell 211 where the gap surface 2111a is located, thereby reducing the weld height and the chance of the flange metal protruding from the outer surface of the shell 211. The method of providing the gap surface 2111a on the shell 211 is relatively simple, easy to form and manufacture, and conducive to reducing costs.

[0096] In the direction from the inside to the outside of the cover plate 212, the distance between the air-avoidance surface 2111a and the third surface 211b gradually increases, which can be understood as the air-avoidance surface 2111a being an inclined surface. As the temperature of the area away from the welding position on the shell 211 gradually decreases, the cast structure formed becomes smaller, and the volume of the weld excess height and the flanging metal is also relatively small. Therefore, the use of this technical solution can adapt to the distribution of the cast structure on the shell 211. More weld excess height and flanging metal on the shell 211 are covered on the side of the air-avoidance surface 2111a close to the cover plate 212, and less weld excess height and flanging metal are covered on the other side of the air-avoidance surface 2111a away from the cover plate 212. This can reduce the probability of insufficient strength of the shell 211 due to the air-avoidance surface 2111a not being covered and filled.

[0097] Alternatively, referring to Figure 8 , the clearance surface 2111a may be connected to the end surface of the housing 211 near the cover plate 212. This technical solution facilitates the processing and manufacturing of the clearance surface 2111a and improves manufacturability. For example, the end surface of the housing 211 near the cover plate 212 is the top surface.

[0098] In the above technical solution, the air-avoiding recess 2111 is provided with an air-avoiding surface 2111a, and the distance between the air-avoiding surface 2111a and the third surface 211b of the shell 211 gradually increases in the direction from the inside to the outside of the cover plate 212. The air-avoiding recess 2111 is constructed as an inclined surface on the shell 211, which is beneficial to reducing the processing difficulty of the air-avoiding recess 2111, and the air-avoiding surface 2111a can adapt to the distribution of the cast structure during the welding of the shell 211, which can reduce the probability of insufficient strength of the shell 2111 due to the inability to cover and fill the air-avoiding surface 2111a.

[0099] In some embodiments of the present application, referring to Figures 5 and 8, the connecting portion 25 has a depth direction and a width direction. In the depth direction, the size of the groove 24 is D1, and in the width direction, the size of the groove 24 is W1, wherein the thickness of the cover plate 212 is T1, W1 = (0.5 ~ 1.2) T1, D1 = (0.5 ~ 1.0) T1.

[0100] The depth direction of the connecting portion 25 may be one of the first direction X and the second direction Y, and the width direction of the connecting portion 25 may be the other of the first direction X and the second direction Y. Referring to FIG5 , the depth direction of the connecting portion 25 may be the second direction Y in the figure, and the width direction may be the first direction X in the figure. Referring to FIG8 , the depth direction of the connecting portion 25 may also be the first direction X in the figure, and the width direction may also be the second direction Y in the figure.

[0101] T1 may be the size of the cover plate 212 in the second direction Y, wherein W2 may refer to the width of the groove 24 , and W1 may be but is not limited to 0.5T1, 0.6T1, 0.7T1, 0.8T1, 0.9T1, 1.0T1, 1.1T1, 1.2T1, and the like.

[0102] In this technical solution, if W1 is less than 0.5T1, the groove width of the groove 24 is relatively small, and the cast structure formed when the cover plate 212 and the shell 211 are welded is not easy to enter the groove 24, which is not conducive to improving the welding height and flanging metal. In addition, the small groove width of the groove 24 also makes the pressure relief passage of the metal vapor relatively narrow, which is not conducive to the pressure relief of the metal vapor; if W1 is greater than 1.2T1, the groove width of the groove 24 is relatively large, and the probability of W1 being greater than the size of the connecting part 25 increases. The probability that the cast structure formed when the cover plate 212 and the shell 211 are welded cannot cover the groove width direction dimension of the groove 24 increases, which easily affects the connection reliability of the cover plate 212 and the shell 211. That is to say, by setting W1 within the range of 0.5T1 to 1.2T1, the cast structure formed during the welding of the cover plate 212 and the shell 211 can more easily enter the groove 24, and is conducive to the pressure release of metal vapor. At the same time, it can also reduce the probability that the cast structure cannot cover the groove width direction dimension of the groove 24, and can improve the connection reliability of the cover plate 212 and the shell 211.

[0103] D1 may refer to a groove depth of the groove 24 , and D1 may be, but is not limited to, 0.5T1, 0.6T1, 0.7T1, 0.8T1, 0.9T1, 1.0T1, and the like.

[0104] In this technical solution, if D1 is less than 0.5T1, the groove depth of the groove 24 is relatively small, and the stamping tear band area that can be removed is limited, which is not conducive to reducing the influence of impurities in the stamping tear band area on welding. In addition, the groove depth of the groove 24 is small, and the groove depth size is effective, which is not conducive to improving the welding excess height and flanging metal problems. If D1 is greater than 1.0T1, the groove depth of the groove 24 is large, and the thickness of the stamping tear band removed on the cover plate 212 is also relatively large. When the cover plate 212 and the shell 211 are welded, there is a high probability that the cast structure cannot fill the groove 24 in the groove depth direction, which easily leads to the presence of a cavity in the cover plate 212, affecting the strength of the cover plate 212. That is to say, by setting D1 within the range of 0.5T1 to 1.0T1, it is beneficial to remove a stamping tear band area of ​​appropriate thickness on the cover plate 212, which is beneficial to reducing the influence of impurities in the stamping tear band area on welding, and can also reduce the probability that the reliability of the cover plate 212 is affected by the large groove depth of the groove 24.

[0105] In the above technical solution, by setting the dimensions D1 and W1 of the groove 24 and the thickness T1 of the cover plate 212 to W1 in the range of 0.5T1 to 1.2T1 and D1 in the range of 0.5T1 to 1.0T1, the groove width and groove depth of the groove 24 can be within an appropriate range, so that the volume of the stamped tear strip removed from the cover plate 212 is more appropriate, the effect of reducing the influence of impurities in the stamped tear strip area on welding is better, the effect of relieving the pressure of metal vapor is also better, and the effect of improving the welding excess height and the flanging metal is also better.

[0106] In some embodiments of the present application, W1 is 0.3 mm to 0.8 mm. It can be understood that W1 can be, but is not limited to, 0.3 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm, 0.80 mm, etc.

[0107] In the above technical solution, if W1 is less than 0.3 mm, the groove width of the groove 24 is small, and the as-cast structure formed when the cover plate 212 and the shell 211 are welded is not easy to enter the groove 24, which is not conducive to improving the weld height and the flange metal. In addition, the small groove width of the groove 24 also makes the metal vapor pressure relief channel narrow, which is not conducive to metal vapor pressure relief. If W1 is greater than 0.8 mm, the probability of W1 being larger than the size of the connecting portion 25 increases, and the probability that the as-cast structure formed when the cover plate 212 and the shell 211 are welded cannot cover the groove width dimension of the groove 24 increases, which easily affects the connection reliability of the cover plate 212 and the shell 211. In other words, by setting the groove width W1 of the groove 24 within the range of 0.3 mm to 0.8 mm, the as-cast structure formed when the cover plate 212 and the shell 211 are welded can more easily enter the groove 24, and it is also conducive to metal vapor pressure relief. At the same time, it can also reduce the probability that the as-cast structure cannot cover the groove width dimension of the groove 24, which can improve the connection reliability of the cover plate 212 and the shell 211.

[0108] In some embodiments of the present application, D1 is 0.3 mm to 0.6 mm. It can be understood that D1 can be, but is not limited to, 0.3 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm, etc.

[0109] In the above technical solution, if D1 is less than 0.3mm, the groove depth of the groove 24 is small, and the stamping tear band area that can be removed is limited, which is not conducive to reducing the impact of impurities in the stamping tear band area on welding. Moreover, the groove depth of the groove 24 is small, and the groove depth size is effective, which is not conducive to improving the welding height and flange metal problems. If D1 is greater than 0.60mm, the groove depth of the groove 24 is large, and the thickness of the stamping tear band removed on the cover plate 212 is also relatively large. When the cover plate 212 and the shell 211 are welded, there is a high probability that the cast structure in the groove depth direction will not be able to fill the groove 24, which is likely to cause a cavity in the cover plate 212 and affect the strength of the cover plate 212. In other words, by setting the groove depth D1 of the groove 24 within the range of 0.3mm to 0.6mm, it is beneficial to remove a stamping tear band area of ​​appropriate thickness on the cover plate 212, which is beneficial to reducing the impact of impurities in the stamping tear band area on welding, and can also reduce the probability that the reliability of the cover plate 212 is affected by the large groove depth of the groove 24.

[0110] In some embodiments of the present application, the thickness T2 of the housing 211 is 0.4 mm to 0.6 mm. It is understood that the thickness T2 of the housing 211 can be, but is not limited to, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, 0.50 mm, 0.52 mm, 0.54 mm, 0.56 mm, 0.58 mm, 0.60 mm, etc.

[0111] In the above technical solution, if the thickness T2 of the housing 211 is less than 0.4 mm, the strength of the housing 211 is insufficient, affecting the reliability of the housing 211. If the thickness T2 of the housing 211 is greater than 0.6 mm, although the strength of the housing 211 meets the requirements, the thickness of the housing 211 is relatively large, and the volume occupied by the battery cell 20 is relatively large, which is not conducive to improving the energy density of the battery cell 20. In other words, by setting the thickness T2 of the housing 211 within the range of 0.4 mm to 0.6 mm, the thickness of the housing 211 is within an appropriate range, which can not only ensure the strength of the housing 211 but also help improve the energy density of the battery cell 20.

[0112] According to the first embodiment of the present application, in the housing assembly 21 of the battery cell 20, the housing 211 is an aluminum shell with a thickness T2 of 0.4 mm. A groove 24 is provided on the peripheral side 212a of the cover plate 212, connecting to the outer side of the cover plate 212. The width W1 of the groove 24 is 0.3 mm, and the depth D1 of the groove 24 is 0.3 mm. Under these dimensions, the post-weld flange and the residual height are both 0 mm.

[0113] According to the second embodiment provided herein, the structure of the battery cell 20 is substantially the same as that of the first embodiment, except that the thickness T2 of the aluminum shell is 0.6 mm, the width W1 of the groove 24 is 0.8 mm, and the depth D1 of the groove 24 is 0.6 mm. Under these dimensions, the post-weld flange and excess height are both 0 mm.

[0114] According to the third embodiment provided in the present application, the structure of the battery cell 20 of the third embodiment is substantially the same as that of the first embodiment, except that a groove 24 is provided on the peripheral side surface 212a of the cover plate 212, the cover plate 212 has an extension portion 2121 protruding from the peripheral side surface 212a, the extension portion 2121 has a first surface 2121a close to the inner side of the cover plate 212, the groove 24 has a second surface 24a away from the inner side of the cover plate 212, and the second surface 24a is flush with the first surface 2121a so that the cover plate 212 is T-shaped.

[0115] In a second aspect, an embodiment of the present application further provides a battery 100 , comprising the aforementioned battery cell 20 .

[0116] In the above technical solution, the battery cell 20 can reduce the stamping tear zone area on the shell 211 and / or the cover plate 212 by setting a groove 24 on the shell 211 and / or the cover plate 212, and can reduce the probability of excess height and flange formation at the weld after welding. It can also relieve the pressure of metal vapor formed by subsequent welding, which is beneficial to improving the welding quality and welding stability of the cover plate 212 and the shell 211, thereby improving the reliability of the battery cell 20.

[0117] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the aforementioned battery cell 20 or the aforementioned battery 100 .

[0118] In the above technical solution, the battery cell 20 or battery 100 can reduce the stamped tear zone area on the shell 211 and / or the cover plate 212 by setting the groove 24 on the shell 211 and / or the cover plate 212, reduce the probability of forming excess height and flange at the weld after welding, and release the pressure of the metal vapor formed by subsequent welding, which is beneficial to improving the reliability of the battery cell 20 or battery 100, and thus beneficial to improving the reliability of the electrical device.

[0119] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0120] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. 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 assembly, comprising a shell and a cover plate, wherein the shell has an opening, the cover plate is arranged to cover the opening, the cover plate has a peripheral side surface, the peripheral side surface and / or the shell are provided with a groove, a connecting portion for sealing the opening is formed between the shell and the cover plate, and the connecting portion is at least partially accommodated in the groove; an electrode terminal, the electrode terminal being arranged on the housing or the cover; An electrode assembly is disposed in the shell and electrically connected to the electrode terminal.

2. The battery cell according to claim 1, wherein: A dividing plane is formed in the thickness direction of the cover plate to divide the cover plate equally, and the groove is located on a side of the dividing plane close to the outside of the cover plate.

3. The battery cell according to claim 1 or 2, wherein: The groove is an annular groove arranged along the circumference of the cover plate.

4. The battery cell according to claim 1 or 2, wherein: The peripheral side surface includes at least one edge surface, each of which is provided with at least one groove; and / or the shell includes at least one inner side surface, each of which is provided with at least one groove.

5. The battery cell according to any one of claims 1 to 4, wherein: The groove is arranged on the peripheral side surface.

6. The battery cell according to claim 5, wherein: The groove is connected to the outer side of the cover plate along the thickness direction of the cover plate.

7. The battery cell according to claim 5, wherein: The cover plate has an extension portion protruding from the peripheral side surface, the extension portion has a first surface close to the inner side of the cover plate, the groove has a second surface away from the inner side of the cover plate, and the second surface is flush with the first surface.

8. The battery cell according to any one of claims 1 to 7, wherein: The shell is provided with a space-avoiding recess, and the space-avoiding recess is located at the outer side of the shell and is arranged opposite to the groove.

9. The battery cell according to claim 8, wherein: The shell has a third surface facing the peripheral side surface, the air avoidance recess has an air avoidance surface, the air avoidance surface is connected to the third surface, and the distance between the air avoidance surface and the third surface gradually increases in the direction from the inside to the outside of the cover plate.

10. The battery cell according to any one of claims 1 to 9, wherein: The connecting portion has a depth direction and a width direction. In the depth direction, the size of the groove is D1, and in the width direction, the size of the groove is W1, wherein the thickness of the cover plate is T1, W1=(0.5~1.2)T1, D1=(0.5~1.0)T1.

11. A battery, wherein: The invention comprises the battery cell according to any one of claims 1 to 10.

12. An electrical device, wherein: The method comprises the battery cell according to any one of claims 1 to 10, or the battery according to claim 11.

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