Battery cells, batteries and electrical devices

Abstract

The present invention relates to a battery cell (20), a battery (100), and an electrical device, wherein the battery cell (20) is a casing assembly (21) including a casing (211) having an opening (211a) and a cover plate (212) covering the opening (211a) and having a circumferential surface (212a), wherein a groove (24) is provided in the circumferential surface (212a) and / or the casing (211), and a connecting portion (25) for sealing the opening (211a) is formed between the casing (211) and the cover plate (212), and the connecting portion (25) is at least partially housed in the groove (24), the casing assembly (21) includes an electrode terminal (22) provided in the casing (211) or the cover plate (212), and an electrode assembly (23) provided inside the casing (211) and electrically connected to the electrode terminal (22).

Description

Cross-reference to Related Applications

[0001] This application is filed based on a Chinese patent application with application number 202323130406.5 and filing date November 20, 2023, claims the priority of the Chinese patent application, and the entire content of the Chinese patent application is incorporated herein by reference.

Technical Field

[0002] This application relates to the field of battery technology, and particularly to battery cells, batteries, and electrical devices.

Background Art

[0003] In recent years, new energy vehicles have achieved remarkable development. In the field of electric vehicles, power batteries play an irreplaceable and important role as the power source of electric vehicles. A battery consists of a case and a plurality of battery cells housed in the case. Among them, as a core component of new energy vehicles, the battery has relatively high requirements both in terms of safety and service life. However, there are reliability problems in the welding of the casing during the manufacturing process of the battery cells inside the battery, which affects the reliability of the entire battery cell, and has a great impact on the performance and service life of the battery.

Summary of the Invention

[0004] Embodiments of this application provide a battery cell, a battery, and an electrical device that can effectively improve the reliability of the battery cell and the battery.

[0005] In a first aspect, embodiments of this application provide a battery cell, which includes a casing assembly having a casing with an opening and a cover plate covering the opening and having a peripheral side surface. A concave groove is provided on the peripheral side surface and / or the casing. A connecting portion for sealing the opening is formed between the casing and the cover plate, and the connecting portion is at least partially accommodated in the concave groove. The casing assembly, an electrode terminal provided on the casing or the cover plate, and an electrode assembly provided in the casing and electrically connected to the electrode terminal are included.

[0006] In the above proposed technology, by providing grooves on the circumferential surface of the cover plate and / or the casing, the grooves can, on the one hand, reduce the stamping tear zone area of ​​the casing and / or cover plate, reduce the influence of impurities in the stamping tear zone area on welding, and improve the welding quality and welding stability between the cover plate and the casing. On the other hand, they can accommodate the cast structure formed during the welding process, reduce the probability of forming excess weld material and flanges at the welded area after welding, and release the metal vapor formed by subsequent welding, further improving the welding quality and welding stability between the cover plate and the casing. In other words, by adopting the above proposal, the reliability of the casing assembly can be improved, the reliability of the battery cells can be improved, the operating performance of the battery cells can be improved, and the service life of the battery cells can be extended.

[0007] In some embodiments of the present invention, a dividing surface is created that divides the cover plate equally in the thickness direction of the cover plate, and the groove is located on the side of the dividing surface that is closer to the outside of the cover plate. In this invention, by having the groove closer to the outside of the cover plate, the connection portion formed between the cover plate and the casing can also be fitted and closer to the outside of the cover plate, which is advantageous in reducing the depth of the slit that is closer to the outside between the cover plate and the casing, reducing the content of substances such as dust or water in the slit, reducing the impact of substances such as dust or water on the connection portion after a long period of time, improving the reliability of the connection between the cover plate and the casing, and further improving the reliability of the battery cell.

[0008] In some embodiments of the present application, the groove is an annular groove installed along the circumferential direction of the cover plate. In this technical proposal, by providing the groove as an annular groove installed along the circumferential direction of the cover plate, the stamping tear band area can be uniformly removed in the circumferential direction of the casing and / or cover plate, and is also advantageous in removing a larger volume of the stamping tear band area, further reducing the influence of the stamping tear band area on the welding between the casing and the cover plate, and is advantageous in improving the welding quality and welding stability between the casing and the cover plate.

[0009] In some embodiments of the present application, the circumferential surface includes at least one edge, each edge having at least one groove, and / or the casing includes at least one inner surface, each inner surface having at least one groove.

[0010] In the above proposed technology, if at least one groove is provided on each edge surface of the circumferential side, it is possible to create a groove on a portion of each edge surface while leaving the rest open. This not only reduces the stamping tear zone area of ​​the cover plate, but also reduces the influence of the groove on the edge strength of the cover plate and improves the connection strength between the cover plate and the casing. If at least one groove is provided on each inner surface of the casing, it is possible to create a groove on a portion of the inner surface of the casing while leaving the rest open. This not only reduces the stamping tear zone area of ​​the casing, but also reduces the influence of the groove on the edge strength of the casing and improves the connection strength between the casing and the cover plate.

[0011] In some embodiments of the present application, the grooves are provided on the circumferential surface. In this technical proposal, by providing grooves in the cover plate and not creating grooves in the casing, the stamping tear band area on the cover plate is reduced, thereby improving the welding quality and welding reliability between the cover plate and the casing. This reduces the weld build-up and flange metal, and is also advantageous for a thinner casing design, i.e., for a relatively small casing thickness. Since the volume and dimensions of the casing are even larger than those of the cover plate, reducing the casing thickness is advantageous for reducing the volume of the battery cells and improving the energy density of the battery cells.

[0012] In some embodiments of the present application, the grooves communicate with the outside of the cover plate along the thickness direction of the cover plate.

[0013] In the above proposed technology, the groove communicates with the outside of the cover plate along the thickness direction of the cover plate, and the groove has an opening on the outside of the cover plate, making it easy to observe the connection between the cover plate and the casing through the opening, which is advantageous for welding operations between the cover plate and the casing. Furthermore, because the groove communicates with the outside of the cover plate, metal vapor can be directly discharged to the outside during welding of the cover plate and the casing, which is advantageous for smooth pressure release of metal vapor.In addition, since the connection is formed at least partially within the groove, the probability of a narrow slit forming between the outer edge of the cover plate and the casing after welding the cover plate and the casing is relatively low, impurities such as dust or water are less likely to accumulate in the groove, which is advantageous for improving the reliability of the connection between the cover plate and the casing.

[0014] In some embodiments of the present application, the cover plate has an extended portion protruding from the circumferential surface, the extended portion has a first surface adjacent to the inside of the cover plate, and the groove has a second surface away from the inside of the cover plate, and the second surface and the first surface are flush.

[0015] In the above proposed technology, the cover plate has an extended portion that protrudes from its circumferential surface, allowing the cover plate to exhibit a T-shaped structure. When the cover plate and the casing are fitted together, the extended portion abuts against the end face of the casing, providing shielding and sealing against the slit between the circumferential surface and the inner surface of the casing, thereby reducing the probability of impurities such as dust and water from the surrounding environment entering the space between the circumferential surface and the inner surface of the casing. The second surface of the groove and the first surface of the extended portion are flush, which allows metal vapor to pass to the outside along the second and first surfaces during welding of the cover plate and the casing, which is advantageous for the smooth release of metal vapor pressure.

[0016] In some embodiments of the present invention, the casing is provided with relief recesses located on the outside of the casing and facing the grooves. In the above technical invention, when welding the casing and the cover plate, the outside of the casing forms a loose cast structure due to the high-temperature action. By adopting a structure in which relief recesses are provided in the casing, the relief recesses can accommodate at least a portion of the cast structure, reducing the probability that the cast structure will protrude from the outer surface of the casing after it has cooled, which is advantageous in reducing the probability of weld buildup and flange metal generation, improving the welding stability between the casing and the cover plate and improving the welding quality.

[0017] In some embodiments of the present application, the casing has a third surface facing the circumferential surface, the relief recess has a relief surface connected to the third surface, and the distance between the relief surface and the third surface gradually increases in the direction from the inside to the outside of the cover plate.

[0018] In the above proposed technology, by installing the relief recess so as to have a relief surface, the distance between the relief surface and the third surface of the casing gradually increases in the direction from the inside to the outside of the cover plate, and the relief recess is configured as a slope on the casing, which is advantageous in reducing the difficulty of machining the relief recess, and the relief surface can adapt to the distribution of the cast microstructure during casing welding, and the probability of insufficient casing strength due to the relief surface not being covered and filled can be reduced.

[0019] In some embodiments of the present application, the connecting portion has a depth direction and a width direction, the dimension of the groove in the depth direction is D1, the dimension of the groove in the width direction is W1, the thickness of the cover plate is T1, W1 = (0.5~1.2)T1, and D1 = (0.5~1.0)T1.

[0020] In the above proposed technology, by setting the dimensions D1 and W1 of the groove and the thickness T1 of the cover plate such that W1 is within the range of 0.5T1 to 1.2T1 and D1 is within the range of 0.5T1 to 1.0T1, the groove width and groove depth of the groove can be set to an appropriate range, the volume of the stamping tear strip removed from the cover plate becomes relatively appropriate, the effect of reducing the influence of impurities in the stamping tear strip area on welding is relatively good, the effect of metal vapor pressure release is relatively good, and at the same time the effect of improving the weld buildup and flange metal is relatively good.

[0021] In a second aspect, the embodiment of the present application further provides a battery including the aforementioned battery cell.

[0022] In the above proposed technology, by providing grooves in the casing and / or cover plate, the stamping tear zone area on the casing and / or cover plate can be reduced, the probability of excess weld material and flange formation at the welded area after welding can be reduced, and the metal vapor formed by subsequent welding can be released, thereby improving the welding quality and welding stability between the cover plate and the casing, and thus improving the reliability of the battery cell.

[0023] In a third aspect, an embodiment of the present application further provides an electrical device including the aforementioned battery cell or the aforementioned battery.

[0024] In the above technical solution, by installing concave grooves on the casing and / or the cover plate of the battery cell or the battery, the stamping tear zone on the casing and / or the cover plate can be reduced, and the probability of forming excess material and flanges at the welded joints after welding can be reduced. It is beneficial to release the metal vapor formed by subsequent welding and improve the reliability of the battery cell or the battery, and thereby it is beneficial to improve the reliability of the electrical device.

Brief Description of the Drawings

[0025] To more clearly illustrate the technical solution of the embodiments of the present application, the drawings used in the embodiments are briefly introduced below. However, it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative labor. [Figure 1] It is a schematic structural diagram of a vehicle provided by some embodiments of the present application. [Figure 2] It is an exploded structural diagram of a battery provided by some embodiments of the present application. [Figure 3] It is a schematic internal structure diagram of a battery cell provided by some embodiments of the present application. [Figure 4] It is a schematic structural diagram of a cover plate provided by some embodiments of the present application. [Figure 5] It is a partial enlarged schematic diagram of FIG. 3. [Figure 6] It is a schematic internal structure diagram of a battery cell provided by some other embodiments of the present application. [Figure 7] It is a schematic structural diagram of a cover plate provided by some further other embodiments of the present application. [Figure 8] It is a partial enlarged schematic diagram of FIG. 6. [Explanation of Symbols]

[0026] Vehicle 1000, battery 100, case 10, first case body 11, second case body 12, battery cell 20, casing assembly 21, casing 211, opening 211a, third surface 211b, relief recess 2111, relief surface 2111a, cover plate 212, circumferential surface 212a, extended portion 2121, first surface 2121a, electrode terminal 22, electrode assembly 23, recessed groove 24, second surface 24a, connection portion 25, equally divided surface 26, controller 200, motor 300, first direction X, second direction Y. [Modes for carrying out the invention]

[0027] To further clarify the purpose, technical proposal, and advantages of the embodiments of this application, the technical proposal of the embodiments will be clearly described below in conjunction with the drawings of the embodiments of this application. However, it should be clear that the embodiments described are only a selection of embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained without creative work by a person skilled in the art fall within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used in this Application have the same meaning as those generally understood by those skilled in the art relating to the Application. Terms used in the Specification of this Application are for illustrative purposes only and are not intended to limit the Application. The terms “includes” and “have,” and any variations thereof, in the description of the Specification, Claims, and the Drawings are intended to cover non-exclusive inclusion. Terms such as “first,” “second,” etc., in the Specification, Claims, or the Drawings are used to distinguish different subjects and are not used to indicate a particular order or priority.

[0029] The “Examples” as used in this Application mean that certain features, structures, or characteristics described in conjunction with the Examples may be included in at least one Example of this Application. The occurrence of such phrase at each location in the Specification does not necessarily refer to the same Example, nor do they represent mutually exclusive, independent, or substitutable Examples.

[0030] In this description, unless otherwise specified or limited, the terms “attachment,” “connection,” “joining,” and “attaching” should be understood broadly to mean, for example, a fixed connection, a removable connection, an integral connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. A person skilled in the art may understand the specific meaning of these terms in this application depending on the specific circumstances.

[0031] In this application, the term "and / or" simply describes a related relationship that explains the related objects, indicating that three types of relationships are possible. For example, A and / or B can represent three situations: A existing alone, A and B existing simultaneously, and B existing alone. In addition, the symbol " / " in this application generally indicates that the preceding and following related objects are in an "or" relationship.

[0032] In the embodiments of this application, the same drawing symbols represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. The dimensions such as thickness, length, and width of various components in the embodiments of this application shown in the attached drawings, as well as the overall thickness, length, and width of the integrated device, are merely illustrative and should not be understood as constituting any limitation to this application.

[0033] In this application, "multiple" refers to two or more (including two).

[0034] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flattened, rectangular, or have other shapes, and the embodiments of this application are not limited to these. Generally, battery cells are classified into three types according to their encapsulation method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, but the embodiments of this application are not limited to these.

[0035] The batteries referred to in the embodiments of this application refer to a single physical module containing one or more battery cells to provide higher voltage and capacity. For example, the batteries referred to in this application may include battery modules or battery packs. A battery generally includes a case for enclosing one or more battery cells or multiple battery modules. The case can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0036] A battery cell comprises a casing, an electrode assembly, and an electrolyte, the casing being used to house the electrode assembly and the electrolyte. The electrode assembly consists of a positive electrode piece, a negative electrode piece, and a separator film. The battery cell functions primarily by relying on the movement of metal ions between the positive and negative electrode pieces. The positive electrode piece includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer being coated on the surface of the positive electrode current collector, and the positive electrode current collector without the positive electrode active material layer protruding from the positive electrode current collector with the positive electrode active material layer, thus forming a positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode piece includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. Negative electrode current collectors without the negative electrode active material layer protrude from the negative electrode current collectors with the negative electrode active material layer, and these negative electrode current collectors without the negative electrode active material layer are designated as negative electrode tabs. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. To ensure that a large current can be carried without melting, multiple positive electrode tabs are stacked, and multiple negative electrode tabs are stacked.

[0037] The separator film material may be PP (polypropylene) or PE (polyethylene), etc. Furthermore, the electrode assembly may have a wound structure or a laminated structure, and the embodiments of this application are not limited thereto.

[0038] In recent years, new energy vehicles have made remarkable progress, and in the electric vehicle sector, power batteries play an indispensable and crucial role as the power source for electric vehicles. A battery consists of a case and multiple battery cells housed within it. Of these, the battery, as a core component of new energy vehicles, is subject to relatively high demands in terms of both safety and cycle life.

[0039] In typical battery cells, the casing assembly includes the casing and a cover plate that covers the casing. The casing and cover plate are generally formed by multiple stamping processes. During the stamping process, several tear bands are present in the casing and cover plate. These tear band areas are prone to contamination with impurities such as metal shavings and oil stains. The presence of these impurities can lead to defects such as bubbles and explosions during the welding assembly process between the casing and cover plate, increasing production costs. On the other hand, during the welding process, the dense forged structure of the casing and cover plate undergoes remelting and cooling crystallization, resulting in a looser cast structure. That is, the weld structure formed after welding the casing and cover plate has a larger volume per unit mass, resulting in excess material and flange formation at the weld joint after welding. Currently, battery cells use roller presses during manufacturing to improve flange formation. However, excessive roller pressing on thin aluminum casings can easily result in the casing being too thin, further increasing the likelihood of leakage at the ends and affecting the reliability of the battery cell. On the other hand, if roller pressing is not performed, the flange will be too large during use of the battery cell, causing wear on the blue film of the battery core and insulation. Lost This also affects the reliability of the battery cells.

[0040] Based on the above considerations, in order to solve the problem of defects such as pores and explosion points existing during welding of the casing and cover plate during the manufacturing process of the battery cell, as well as the phenomenon of excess weld and flanges existing after welding, the inventors have designed a battery cell including a casing assembly, electrode terminals and an electrode assembly, wherein the casing assembly includes a casing having an opening and a cover plate covering the opening and having a circumferential surface, the circumferential surface and / or the casing is provided with a groove, a connection portion is formed between the casing and the cover plate to seal the opening, the connection portion is at least partially housed in the groove, the electrode terminals are provided on the casing or the cover plate, and the electrode assembly is provided inside the casing and electrically connected to the electrode terminals.

[0041] In a battery cell with such a structure, by providing grooves on the circumferential surface of the cover plate and / or the casing, a connection portion for sealing the opening is formed between the casing and the cover plate, and the connection portion is at least partially housed in the grooves, which can reduce the volume of the stamping tear band area of ​​the casing and / or cover plate. Adopting this structure reduces impurities such as metal shavings and oil stains during the welding process between the casing and the cover plate, thereby reducing the probability of defects such as pores and explosion points occurring during the welding process. On the other hand, the grooves can accommodate the cast structure formed during the welding process, reducing the problem of excess weld material and flanges formed at the welded area after welding, or reducing the probability of excess weld material and flanges formed at the welded area after welding, and can provide an effective metal vapor pressure relief groove for subsequent welding, which is advantageous in improving welding stability. In other words, adopting the above method is advantageous in improving the reliability of the casing assembly, further improving the reliability of the battery cell, improving the operating performance of the battery cell, and extending the service life of the battery cell.

[0042] The batteries disclosed in the embodiments of this application can be used in, but are not limited to, electrical devices such as vehicles, ships, and aircraft. The battery cells, batteries, etc. disclosed in this application can be used to configure a power supply system for such electrical devices.

[0043] Embodiments of the present invention provide an electrical device that uses a battery as a power source, which may be, but is not limited to, a mobile phone, tablet, laptop computer, electric toy, power tool, electric scooter, electric vehicle, ship, or aerospace vehicle. Among these, electric toys may include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, and aerospace vehicles may include airplanes, rockets, space shuttles, and spacecraft.

[0044] In the following embodiments, for the sake of explanation, we will describe an example in which the electrical device according to one embodiment of the present application is a vehicle 1000.

[0045] Referring to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided by some embodiments of the present application, the vehicle 1000 may be a fuel cell vehicle, a gas vehicle, or a new energy vehicle, the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. A battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed in the bottom, head, or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 can function as the operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 for controlling the battery 100 to supply power to the motor 300, and is used, for example, to meet the operating power needs of the vehicle 1000 during starting, navigation, and driving.

[0046] In some embodiments of the present invention, the battery 100 may not only be used as an operating power source for the vehicle 1000, but can also be used as a driving power source for the vehicle 1000, providing driving force to the vehicle 1000 by completely or partially replacing fuel or natural gas.

[0047] Referring 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 comprises a case 10 and a plurality of battery cells 20, the battery cells 20 being used to house in the case 10. The case 10 is used to provide assembly space for the battery cells 20, and the case 10 can employ various structures. In some embodiments, the case 10 may include a first case body 11 and a second case body 12, the first case body 11 and the second case body 12 covering each other, and the first case body 11 and the second case body 12 jointly define assembly space for housing the battery cells 20. The second case body 12 may be a hollow structure with one end open, and the first case body 11 may be a plate-like structure. The first case body 11 is covered by the open side of the second case body 12 so that the first case body 11 and the second case body 12 jointly limit the assembly space. Both the first case body 11 and the second case body 12 may be hollow structures with one side open, and the open side of the first case body 11 is covered by the open side of the second case body 12. Of course, the shape of the case 10 formed by the first case body 11 and the second case body 12 may be various shapes such as a cylinder or a rectangular parallelepiped.

[0048] In the battery 100, the multiple battery cells 20 can be connected in series, in parallel, or in series-parallel, where series-parallel connection means that the multiple battery cells 20 are connected in both series and parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in series-parallel, and the entire assembly of the multiple battery cells 20 is housed in a case 10. Of course, the battery 100 may be in a form where the multiple battery cells 20 are first connected in series, in parallel, or in series-parallel to form a battery module, and the multiple battery modules are further connected in series, in parallel, or in series-parallel to form an entire assembly, and housed in a case 10. The battery 100 may further include other structures, for example, the battery 100 may further include bus members for realizing electrical connections between the multiple battery cells 20.

[0049] Referring to Figure 2, in some embodiments of the present application, the battery 100 may include a plurality of rows of battery cells 20 arranged along the length of the case 10, and each row of battery cells 20 includes a plurality of battery cells 20 arranged along the width of the case 10. Alternatively, the plurality of rows of battery cells 20 are arranged along the width of the case 10, and each row of battery cells 20 includes a plurality of battery cells 20 arranged along the length of the case 10.

[0050] Among these, each battery cell 20 may be a secondary battery or a primary battery, and may be, but is not limited to, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery. The battery cell 20 may be cylindrical, flattened, rectangular, or have other shapes. Exemplarily, in Figure 3, the shape of the battery cell 20 is a rectangular parallelepiped.

[0051] Referring to some embodiments of the present application, specifically Figure 3, Figure 3 is a battery cell 20 provided by an embodiment of the present application, comprising a casing assembly 21, electrode terminals 22 and an electrode assembly 23, wherein the casing assembly 21 comprises a casing 211 having an opening 211a and a cover plate 212 covering the opening 211a and having a circumferential surface 212a, the circumferential surface 212a and / or the casing 211 having a groove 24, a connecting portion 25 for sealing the opening 211a formed between the casing 211 and the cover plate 212, the connecting portion 25 at least partially housed in the groove 24, the electrode terminals 22 provided on the casing 211 or the cover plate 212 and the electrode assembly 23 provided inside the casing 211 and electrically connected to the electrode terminals 22.

[0052] The casing 211 is used to house the electrode assembly 23 and the electrolyte, and the cover plate 212 is used to cover the opening 211a of the casing 211 and serves to seal the casing 211. Selectively, the casing 211 may be, but is not limited to, an aluminum casing or a steel casing.

[0053] The electrode terminal 22 can refer to a component for electrically connecting to an electrode of an external conductor or another adjacent battery cell 20 within the battery group. Specifically, the electrode terminal 22 may be understood as an electrode 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 electrical device. Details of the electrode assembly 23 have been described above and will not be explained here.

[0054] Since the casing 211 and cover plate 212 are generally formed by multiple stamping processes, tear bands exist in the casing 211 and cover plate 212 during the stamping process. Of these, the tear band area of ​​the cover plate 212 is concentrated on the circumferential surface 212a, and the tear band area of ​​the casing 211 is concentrated at the end adjacent to the opening 211a. In a battery cell 20 with the above structure, providing grooves 24 in the cover plate 212 and / or casing 211 can reduce the tear band area.

[0055] Specifically, the groove 24 can be provided in the region of the circumferential surface 212a that forms the connection portion 25 with the casing 211, thereby reducing the tear zone area of ​​the cover plate 212; or the groove 24 can be installed in the region of the casing 211 that forms the connection portion 25 with the cover plate 212, thereby reducing the tear zone area of ​​the casing 211; or the groove 24 can be installed in the region that forms the connection portion 25 with both the casing 211 and the circumferential surface 212a, thereby reducing the tear zone area of ​​both the cover plate 212 and the casing 211.

[0056] The connecting portion 25 can refer to the joint formed after welding the circumferential surface 212a of the cover plate 212 to the casing 211. The connecting portion 25 may be partially housed within the groove 24, or it may be fully housed within the groove 24.

[0057] The groove 24 can reduce the stamping tear zone area of ​​the casing 211 and / or cover plate 212, and when welding the cover plate 212 and the casing 211, the groove 24 can reduce impurities such as metal shavings and oil stains during the welding process, reduce the probability of defects such as pores and explosion points occurring during the welding process, and improve the weld quality between the cover plate 212 and the casing 211.

[0058] Furthermore, the groove 24 includes a accommodating space, and during the welding process between the cover plate 212 and the casing 211, a dense forged structure melts and cools, after which a loose cast structure is formed. This cast structure can generate excess flange metal. Therefore, in this application, part or all of the flange metal formed by welding is located within the groove 24, reducing the probability of the flange metal protruding from the cover plate 212 or the casing 211, and further reducing the problem of excess material and metal flange formation after welding. During the welding process between the cover plate 212 and the casing 211, metal vapor is formed, and the groove 24 can be used as a pressure relief groove to release the metal vapor, improving the stability of the weld pool and improving the welding stability between the cover plate 212 and the casing 211.

[0059] In the above proposed solution, by providing grooves 24 on the circumferential surface 212a of the cover plate 212 and / or the casing 211, the grooves 24 can, on the one hand, reduce the stamping tear zone area of ​​the casing 211 and / or cover plate 212, reduce the influence of impurities in the stamping tear zone area on welding, and improve the welding quality and welding stability between the cover plate 212 and the casing 211. On the other hand, they can accommodate the cast structure formed during the welding process, reduce the probability of forming excess weld material and flanges at the welded area after welding, and release the metal vapor formed by subsequent welding, thereby further improving the welding quality and welding stability between the cover plate 212 and the casing 211. In other words, by adopting the above solution, the reliability of the casing assembly 21 can be improved, the reliability of the battery cell 20 can be improved, the operating performance of the battery cell 20 can be improved, and the service life of the battery cell 20 can be extended.

[0060] In some embodiments of the present application, referring to Figure 4, an equal division surface 26 is created that divides the cover plate 212 equally in the thickness direction of the cover plate 212, and the groove 24 is located on the side of the equal division surface 26 that is close to the outside of the cover plate 212.

[0061] "The thickness direction of the cover plate 212" can refer to the second direction Y in Figure 4.

[0062] In the above proposed technology, the groove 24 is positioned closer to the outside of the cover plate 212, allowing the connection portion 25 formed between the cover plate 212 and the casing 211 to also be positioned closer to the outside of the cover plate 212. This reduces the depth of the slit that is closer to the outside between the cover plate 212 and the casing 211, thereby reducing the amount of dust or water contained in the slit, reducing the impact of dust or water on the connection portion 25 over time, improving the reliability of the connection between the cover plate 212 and the casing 211, and further improving the reliability of the battery cell 20.

[0063] In some embodiments of the present application, the groove 24 is an annular groove provided along the circumferential direction of the cover plate 212.

[0064] When a groove 24 is installed in the casing 211, the groove 24 is an annular groove installed on the casing 211 along the circumferential direction of the cover plate 212, that is, the groove 24 is installed around the casing 211. When a groove 24 is installed in the cover plate 212, the groove 24 is an annular groove installed on the circumferential surface 212a along the circumferential direction of the cover plate 212, that is, the groove 24 is installed around the cover plate 212.

[0065] Selectively, the cross-section of the annular groove in the thickness direction of the cover plate 212 may be rectangular, semicircular, or arc-shaped, and is not limited to these. For example, referring to Figures 3 to 8, the cross-section of the annular groove is rectangular.

[0066] In the groove 24 of the above structure, on the one hand, by making the groove 24 an annular groove, the circumferential stamping tear band area of ​​the casing 211 and / or cover plate 212 can be uniformly reduced, thereby improving the circumferential alignment of the connection portion 25 between the casing 211 and the cover plate 212, and improving the welding quality and welding stability between the casing 211 and the cover plate 212. Furthermore, the fact that the groove 24 is an annular groove is advantageous in removing a larger volume of stamping tear band area on the casing 211 and / or cover plate 212, reducing the influence of impurities in the stamping tear band area on the welding between the casing 211 and the cover plate 212, and thus improving welding quality and welding stability. On the other hand, since the groove 24 is an annular groove, it is easier to machine onto the casing 211 and / or cover plate 212, reducing the groove 24 forming step, further saving labor time and improving work efficiency.

[0067] In the above proposed technology, by providing the groove 24 as an annular groove installed along the circumferential direction of the cover plate 212, the stamping tear band region can be uniformly removed in the circumferential direction of the casing 211 and / or cover plate 212. This is also advantageous in removing a larger volume of the stamping tear band region, further reducing the influence of the stamping tear band region on the welding of the casing 211 and cover plate 212, and is advantageous in improving the welding quality and welding stability of the casing 211 and cover plate 212.

[0068] In some embodiments of the present application, the circumferential surface 212a includes at least one edge surface, each edge surface having at least one groove 24, and / or the casing 211 includes at least one inner surface, each inner surface having at least one groove 24.

[0069] The casing 211 may be a polygonal casing, for example, a triangular casing, a square casing, a pentagonal casing, etc., and each side of the casing 211 corresponds to one inner surface. Correspondingly, the shape of the cover plate 212 is the same as the shape of the casing 211, and the cover plate 212 may be a triangle, a square, a pentagon, etc., but is not limited to these, and the number of edges of the circumferential surface 212a and the inner surfaces of the casing 211 are the same. Exemplarily, the casing 211 is a square casing, the casing 211 includes four inner surfaces, and the circumferential surface 212a includes four edges.

[0070] When grooves 24 are provided on the circumferential surface 212a, at least one groove 24 is provided on each edge of the circumferential surface 212a, that is, one or more grooves 24 may be provided on each edge. This method has advantages: on the one hand, the grooves 24 remove a portion of the stamping tear band area on the circumferential surface 212a, reducing the impact on welding of the stamping tear band area of ​​the cover plate 212; on the other hand, the grooves do not occupy a large portion of the circumferential surface 212a, that is, grooves are not made on a portion of the circumferential surface 212a, reducing the impact of groove formation on the circumferential strength of the cover plate 212 and improving the connection strength between the cover plate 212 and the casing 211.

[0071] When grooves 24 are provided in the casing 211, at least one groove 24 is provided on each inner surface, that is, one or more grooves 24 may be provided on each inner surface. This method has advantages in that, on the one hand, the grooves 24 remove a portion of the stamping tear band area on the casing 211, reducing the impact of the stamping tear band area on welding of the casing 211, and on the other hand, the grooves do not occupy a large portion of the casing 211, that is, grooves are not made on a portion of the inner surface of the casing 211, reducing the impact of groove making on the circumferential strength of the casing 211 and improving the connection strength between the casing 211 and the cover plate 212.

[0072] When grooves 24 are simultaneously installed on the circumferential surface 212a and the casing 211, at least one groove 24 is provided on each edge surface of the circumferential surface 212a, and at least one groove 24 is provided on each inner surface. This method allows the grooves 24 to remove a portion of the stamping tear band area on the casing 211 and the cover plate 212, respectively, and reduces the impact of grooving on the strength of the casing 211 and the cover plate 212, which is advantageous in improving the connection strength between the casing 211 and the cover plate 212.

[0073] In the above proposed technology, if at least one groove 24 is provided on each edge surface of the circumferential surface 212a, a groove can be made on a portion of each edge surface while leaving the rest blank. This not only reduces the stamping tear zone area of ​​the cover plate 212, but also reduces the influence 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 casing 211. If at least one groove 24 is provided on each inner surface of the casing 211, a groove can be made on a portion of the inner surface of the casing 211 while leaving the rest blank. This not only reduces the stamping tear zone area of ​​the casing 211, but also reduces the influence of the groove 24 on the edge strength of the casing 211, thereby improving the connection strength between the casing 211 and the cover plate 212.

[0074] In some embodiments of the present application, referring to Figures 3, 5, 6, and 8, the groove 24 is provided on the circumferential surface 212a.

[0075] A groove 24 is provided on the circumferential surface 212a of the cover plate 212, but it can be understood that no groove is made on the inner surface of the casing 211. Furthermore, the groove 24 may be an annular groove provided on the circumferential surface 212a, or one or more grooves 24 may be provided on each edge surface of the circumferential surface 212a.

[0076] In the above proposed technology, by providing grooves 24 in the cover plate 212 and not creating grooves in the casing 211, the stamping tear band area on the cover plate 212 can be reduced, thereby improving the welding quality and welding reliability between the cover plate 212 and the casing 211. This reduces the weld build-up and flange metal, and is also advantageous for a thinner casing 211 design, i.e., for a relatively small wall thickness of the casing 211. Since the volume and dimensions of the casing 211 are even larger than those of the cover plate 212, reducing the wall thickness of the casing 211 is advantageous for reducing the volume of the battery cell 20 and improving the energy density of the battery cell 20.

[0077] In some embodiments of the present application, referring to Figures 3 to 5, the groove 24 communicates with the outside of the cover plate 212 along the thickness direction of the cover plate 212. The groove 24 can be understood to have two openings, one of which is located on the circumferential surface 212a and the other on the outer surface of the cover plate 212.

[0078] In the above proposed technology, the groove 24 communicates with the outside of the cover plate 212 along the thickness direction of the cover plate 212, and the groove 24 has a groove opening on the outside of the cover plate 212. Since the connection portion 25 between the cover plate 212 and the casing 211 can be easily observed through this groove opening, it is advantageous for welding operations between the cover plate 212 and the casing 211. Furthermore, because the groove 24 communicates with the outside of the cover plate 212, metal vapor can be directly discharged to the outside during welding of the cover plate 212 and the casing 211, which is advantageous for smooth pressure release of metal vapor. In addition, since the connection portion 25 is formed at least partially within the groove 24, the probability of a narrow slit forming between the outer edge of the cover plate 212 and the casing 211 after welding is relatively low, impurities such as dust or water are less likely to accumulate in the groove 24, which is advantageous for improving the reliability of the connection between the cover plate 212 and the casing 211.

[0079] In some embodiments of the present application, referring to Figures 6 to 8, the cover plate 212 has an extended portion 2121 protruding from the circumferential surface 212a, the extended portion 2121 has a first surface 2121a adjacent to the inside of the cover plate 212, and the groove 24 has a second surface 24a away from the inside of the cover plate 212, and the second surface 24a and the first surface 2121a are flush.

[0080] In the above proposed technology, the cover plate 212 has an extended portion 2121 that protrudes from the circumferential surface 212a, allowing the cover plate 212 to exhibit a T-shaped structure. When the cover plate 212 and the casing 211 are fitted together, the extended portion 2121 abuts against the end face of the casing 211, providing shielding and sealing against the slit between the circumferential surface 212a and the inner surface of the casing 211, thereby reducing the probability of impurities such as dust and water from the surrounding environment entering the space between the circumferential surface 212a and the inner surface of the casing 211. The second surface 24a of the groove 24 and the first surface 2121a of the extended portion 2121 are flush, which allows metal vapor to pass to the outside along the second surface 24a and the first surface 2121a during welding of the cover plate 212 and the casing 211, which is advantageous for the smooth release of metal vapor pressure.

[0081] In some embodiments of the present invention, referring to Figure 8, the casing 211 is provided with a relief recess 2111 located on the outside of the casing 211 and facing the groove 24.

[0082] The relief recess 2111 can refer to a recessed area on the outside of the casing 211 that faces the groove 24. Specifically, the relief recess 2111 may be, for example, a groove or a chamfer, and is not limited to these.

[0083] In the above proposed technology, when welding the casing 211 and the cover plate 212, the outside of the casing 211 forms a loose cast structure due to the high-temperature action. By adopting a structure in which a relief recess 2111 is installed in the casing 211, the relief recess 2111 can accommodate at least a portion of the cast structure, reducing the probability that the cast structure will protrude from the outer surface of the casing 211 after it has cooled, which is advantageous in reducing the probability of welding excess and flange metal generation, thereby improving the welding stability between the casing 211 and the cover plate 212 and improving the welding quality.

[0084] In some embodiments of the present application, referring to Figure 8, the casing 211 has a third surface 211b facing the circumferential surface 212a, and the relief recess 2111 has a relief surface 2111a connected to the third surface 211b, and the distance between the relief surface 2111a and the third surface 211b gradually increases in the direction from the inside to the outside of the cover plate 212.

[0085] When the casing 211 and the cover plate 212 are welded together, the cast structure formed on the outer surface of the casing 211 by high-temperature action covers the flank 2111a, filling the defect where the flank 2111a is located on the casing 211, and reducing the probability that the weld buildup and flange metal formed by welding will protrude from the outer surface of the casing 211. Adopting a method of installing a flank 2111a on the casing 211 is relatively simple, easy to manufacture, and advantageous in reducing costs.

[0086] As the distance between the flank surface 2111a and the third surface 211b increases from the inside to the outside of the cover plate 212, it can be understood that the flank surface 2111a is a slope. In areas on the casing 211 away from the welding position, as the temperature gradually decreases, the formed cast structure decreases, and the volume of weld reinforcement and flange metal also becomes relatively small. By adopting this technical method, it is possible to adapt to the distribution of the cast structure on the casing 211. A relatively large amount of weld reinforcement and flange metal on the casing 211 is covered on the side of the flank surface 2111a that is close to the cover plate 212, and a relatively small amount of weld reinforcement and flange metal is covered on the other side of the flank surface 2111a that is away from the cover plate 212. This reduces the probability of insufficient strength in the casing 211 due to inadequate covering and filling of the flank surface 2111a.

[0087] Selectively, referring to Figure 8, the flank surface 2111a can abut against the end face of the casing 211 that is close to the cover plate 212. Adopting this technical approach, the flank surface 2111a abuts against the end face of the cover plate 212, which is advantageous for the processing and manufacturing of the flank surface 2111a and improves manufacturability. Exemplarily, the end face of the casing 211 that is close to the cover plate 212 is the front end face.

[0088] In the above proposed technology, by installing the relief recess 2111 with a relief surface 2111a, the distance between the relief surface 2111a and the third surface 211b of the casing 211 gradually increases in the direction from the inside to the outside of the cover plate 212, and the relief recess 2111 is configured as a slope on the casing 211, which is advantageous in reducing the difficulty of machining the relief recess 2111. Furthermore, the relief surface 2111a can adapt to the distribution of the cast microstructure during welding of the casing 211, and the probability of insufficient strength of the casing 211 due to the relief surface 2111a not being covered and filled can be reduced.

[0089] 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, the dimension of the groove 24 is D1 in the depth direction, the dimension of the groove 24 is W1 in the width direction, the thickness of the cover plate 212 is T1, W1 = (0.5~1.2)T1, and D1 = (0.5~1.0)T1.

[0090] The depth direction of the connection portion 25 may be either the first direction X or the second direction Y, and the width direction of the connection portion 25 may be the other of the first direction X or the second direction Y. Referring to Figure 5, the depth direction of the connection 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 Figure 8, the depth direction of the connection portion 25 may also be the first direction X in the figure, and the width direction may be the second direction Y in the figure.

[0091] T1 may be a dimension of the cover plate 212 in the second direction Y, where W1 can refer to the groove width of the recessed 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, etc.

[0092] In this proposed technology, if W1 is less than 0.5T1, the groove width of the groove 24 is relatively small, making it difficult for the cast structure formed during welding of the cover plate 212 and the casing 211 to enter the groove 24, which is detrimental to improving the weld buildup and flange metal. Also, because the groove width of the groove 24 is relatively small, the pressure relief passage for metal vapor becomes relatively narrow, which is detrimental to the pressure relief of metal vapor. If W1 is greater than 1.2T1, the groove width of the groove 24 is relatively large, increasing the probability that W1 will be larger than the dimensions of the connection part 25. This increases the probability that the cast structure formed during welding of the cover plate 212 and the casing 211 will not be able to cover the dimensions of the groove 24 in the groove width direction, which is likely to affect the reliability of the connection between the cover plate 212 and the casing 211. In other words, by setting W1 within the range of 0.5T1 to 1.2T1, it is advantageous for the cast structure formed during welding of the cover plate 212 and the casing 211 to relatively easily enter the groove 24, and is also advantageous for releasing metal vapor pressure. Furthermore, it is possible to reduce the probability that the cast structure will not be able to cover the dimensions of the groove 24 in the groove width direction, thereby improving the reliability of the connection between the cover plate 212 and the casing 211.

[0093] D1 can refer to the groove depth of the recessed groove 24, and D1 may be 0.5T1, 0.6T1, 0.7T1, 0.8T1, 0.9T1, 1.0T1, etc., but is not limited to these.

[0094] In the proposed technology, when D1 is less than 0.5T1, the groove depth of the groove 24 is relatively small, limiting the area of ​​stamping tearing that can be removed, which is disadvantageous in reducing the influence of impurities within the stamping tearing area on welding. Furthermore, the groove depth of the groove 24 is relatively small, and the groove depth dimension is limitedTherefore, setting D1 to a value greater than 1.0T1 is advantageous in improving the problems of weld buildup and flange metal. When D1 is greater than 1.0T1, the groove depth of the groove 24 is relatively large, the thickness of the removed stamping tear band on the cover plate 212 is relatively large, and the probability that the cast structure will not be able to fill the groove 24 in the groove depth direction during welding of the cover plate 212 to the casing 211 is relatively high, making it easier for voids to exist in the cover plate 212 and affecting the strength of the cover plate 212. In other words, setting D1 within the range of 0.5T1 to 1.0T1 is advantageous in removing a stamping tear band area of ​​appropriate thickness on the cover plate 212, is advantageous in reducing the influence of impurities in the stamping tear band area on welding, and can also reduce the probability that the relatively large groove depth dimension of the groove 24 will affect the reliability of the cover plate 212.

[0095] In the above proposed technology, by setting the dimensions D1 and W1 of the groove 24 and the thickness T1 of the cover plate 212 such that W1 is within the range of 0.5T1 to 1.2T1 and D1 is within the range of 0.5T1 to 1.0T1, the groove width and groove depth of the groove 24 can be set to an appropriate range, the volume of the stamping tear strip removed from the cover plate 212 becomes relatively appropriate, the effect of reducing the influence of impurities in the stamping tear strip region on welding is relatively good, the effect of metal vapor pressure release is also relatively good, and at the same time the effect of improving the weld buildup and flange metal is also relatively good.

[0096] In some embodiments of this application, W1 is 0.3 mm to 0.8 mm. W1 may also be 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., and is not limited to these.

[0097] In the above proposed technology, if W1 is less than 0.3 mm, the groove width of the groove 24 is relatively small, making it difficult for the cast structure formed during welding of the cover plate 212 and the casing 211 to enter the groove 24, which is detrimental to improving the weld buildup and flange metal. Also, because the groove width of the groove 24 is relatively small, the pressure relief passage for metal vapor becomes relatively narrow, which is detrimental to the pressure relief of metal vapor. If W1 is greater than 0.8 mm, the probability that W1 will be larger than the dimensions of the connection part 25 increases, and the probability that the cast structure formed during welding of the cover plate 212 and the casing 211 will not be able to cover the dimensions of the groove 24 in the groove width direction increases, which is likely to affect the reliability of the connection between the cover plate 212 and the casing 211. Specifically, by setting the groove width W1 of the groove 24 within the range of 0.3 mm to 0.8 mm, it is advantageous for the cast structure formed during welding of the cover plate 212 and the casing 211 to enter the groove 24 relatively easily, and is also advantageous for releasing metal vapor pressure. Furthermore, it is possible to reduce the probability that the cast structure will not be able to cover the dimensions of the groove 24 in the groove width direction, thereby improving the reliability of the connection between the cover plate 212 and the casing 211.

[0098] In some embodiments of this application, D1 is 0.3 mm to 0.6 mm. D1 may also be 0.3 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm, etc., and is not limited to these.

[0099] In the above proposed technology, when D1 is less than 0.3 mm, the groove depth of the groove 24 is relatively small, limiting the area of ​​stamping tear band that can be removed, which is disadvantageous in reducing the influence of impurities within the stamping tear band area on welding. Also, when the groove depth of the groove 24 is relatively small, the dimensions of the groove depth are limitedThis is disadvantageous for improving the problems of weld buildup and flange metal. If D1 is greater than 0.60 mm, the groove depth of the groove 24 is relatively large, the thickness of the removed stamping tear band on the cover plate 212 is relatively large, and there is a high probability that the cast structure will not be able to fill the groove 24 in the groove depth direction when welding the cover plate 212 to the casing 211, making it easier for voids to exist in the cover plate 212 and affecting the strength of the cover plate 212. In other words, setting the groove depth D1 of the groove 24 within the range of 0.3 mm to 0.6 mm is advantageous for removing a stamping tear band area of ​​appropriate thickness on the cover plate 212, is advantageous for reducing the influence of impurities in the stamping tear band area on welding, and can also reduce the probability that the relatively large groove depth dimension of the groove 24 will affect the reliability of the cover plate 212.

[0100] In some embodiments of the present application, the thickness T2 of the casing 211 is 0.4 mm to 0.6 mm. The thickness T2 of the casing 211 may also be 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., and is not limited to these.

[0101] In the above proposed technology, if the thickness T2 of the casing 211 is less than 0.4 mm, the strength of the casing 211 is insufficient, affecting the reliability of the casing 211. If the thickness T2 of the casing 211 is greater than 0.6 mm, the strength of the casing 211 can meet the requirements, but the thickness of the casing 211 is relatively large, and the volume it occupies within the battery cell 20 is relatively large, which is disadvantageous for improving the energy density of the battery cell 20. In other words, by setting the thickness T2 of the casing 211 within the range of 0.4 mm to 0.6 mm, the thickness of the casing 211 is within an appropriate range, allowing for both sufficient strength of the casing 211 and an advantage in improving the energy density of the battery cell 20.

[0102] According to Embodiment 1 provided in this application, in the casing assembly 21 of the battery cell 20, the casing 211 is an aluminum casing with a thickness T2 of 0.4 mm, a groove 24 is provided on the circumferential surface 212a of the cover plate 212, the groove 24 communicates with the outer surface 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 the conditions for assembling a casing cover plate of these dimensions, the flange and excess weld after welding are both 0 mm.

[0103] According to Example 2 provided in this application, the structure of the battery cell 20 in Example 2 is substantially the same as that of Example 1, the difference being that the thickness T2 of the aluminum casing 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 the conditions for assembling a casing cover plate of these dimensions, the flange and excess weld after welding are both 0 mm.

[0104] According to Embodiment 3 provided in this application, the structure of the battery cell 20 in Embodiment 3 is substantially the same as that of Embodiment 1, the difference being that a groove 24 is provided on the circumferential surface 212a of the cover plate 212, the cover plate 212 has an extended portion 2121 that protrudes from the circumferential surface 212a, the extended portion 2121 has a first surface 2121a that is close to the inside of the cover plate 212, the groove 24 has a second surface 24a that is away from the inside of the cover plate 212, and the second surface 24a and the first surface 2121a are flush so that the cover plate 212 exhibits a T-shape.

[0105] In a second aspect, the embodiment of the present application further provides a battery 100 including the aforementioned battery cell 20.

[0106] In the above proposed technology, by providing grooves 24 in the casing 211 and / or cover plate 212, the battery cell 20 can reduce the stamping tear zone area on the casing 211 and / or cover plate 212, reduce the probability of excess material and flanges being formed at the welded area after welding, and release the metal vapor formed by subsequent welding, thereby improving the welding quality and welding stability between the cover plate 212 and the casing 211, and thus improving the reliability of the battery cell 20.

[0107] In a third aspect, the embodiment of the present application further provides an electrical device including the aforementioned battery cell 20 or the aforementioned battery 100.

[0108] In the above proposed technology, the battery cell 20 or battery 100 can reduce the stamping tear band area on the casing 211 and / or cover plate 212 by providing grooves 24 in the casing 211 and / or cover plate 212, thereby reducing the probability of excess material and flanges being formed at the welded area after welding, which is advantageous for releasing the metal vapor formed by subsequent welding and improving the reliability of the battery cell 20 or battery 100, and thereby advantageous for improving the reliability of the electrical device.

[0109] As long as there is no contradiction, the embodiments and features described herein can be combined with each other.

[0110] The foregoing are merely preferred embodiments of the present application and do not limit it, and various modifications and changes are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application should be included in the claims of the present application.

Claims

1. It is a battery cell, A casing assembly comprising a casing having an opening and a cover plate covering the opening and having a circumferential surface, wherein the circumferential surface and / or the casing are provided with a groove, and a connecting portion for sealing the opening is formed between the casing and the cover plate, and the connecting portion is at least partially housed in the groove, Electrode terminals provided on the casing or cover plate, The electrode assembly is provided within the casing and electrically connected to the electrode terminals, Battery cell.

2. The cover plate is divided into equal parts in the thickness direction, and the groove is located on the side of the equal division surface that is closer to the outside of the cover plate. The battery cell according to claim 1.

3. The groove is an annular groove installed along the circumferential direction of the cover plate. The battery cell according to claim 1 or 2.

4. The circumferential surface includes at least one edge, each of which is provided with at least one groove, and / or the casing includes at least one inner surface, each of which is provided with at least one groove. The battery cell according to claim 1 or 2.

5. The groove is provided on the circumferential surface, A battery cell according to any one of claims 1 to 4.

6. The groove communicates with the outside of the cover plate along the thickness direction of the cover plate. The battery cell according to claim 5.

7. The cover plate has an extended portion protruding from the circumferential surface, the extended portion has a first surface close to the inside of the cover plate, and the groove has a second surface away from the inside of the cover plate, and the second surface and the first surface are flush. The battery cell according to claim 5.

8. The casing is provided with a relief recess located on the outside of the casing and facing the groove. A battery cell according to any one of claims 1 to 7.

9. The casing has a third surface directly facing the circumferential surface, the relief recess has a relief surface connected to the third surface, and the distance between the relief surface and the third surface gradually increases in the direction from the inside to the outside of the cover plate. The battery cell according to claim 8.

10. The connecting portion has a depth direction and a width direction, and in the depth direction, the dimension of the groove is D １ The dimensions of the groove are W in the width direction. １ And of these, the thickness of the cover plate is T １ And, W １ =(0.5~1.2)T １ And D １ =(0.5~1.0)T １ That is, A battery cell according to any one of claims 1 to 9.

11. A battery cell according to any one of claims 1 to 10, battery.

12. A battery cell according to any one of claims 1 to 10 or a battery according to claim 11, Electrical device.

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