Battery cell, battery device, and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises an end cover, a shell, an electrode assembly and a pole. The end cover is connected to the shell. The end cover and the shell form an accommodating space. The pole is arranged on the end cover. The pole comprises a connecting body and a connecting support arm. The connecting body and the connecting supporting arm are located in the containing space. One end of the connecting support arm is connected with the connecting body. And the connecting body and the connecting support arm are integrally formed. The electrode assembly is arranged in the accommodating space. The electrode assembly includes a tab. And the connecting body and the connecting support arms are welded with the tabs to form welding marks.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. Improving battery safety has always been a key research direction in battery technology development. Utility Model Content

[0003] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, which helps to improve the safety of the battery device.

[0004] This application provides a battery cell, which includes an end cap, a housing, an electrode assembly, and a terminal post. The end cap is connected to the housing. The end cap and the housing form a receiving space. The terminal post is disposed on the end cap. The terminal post includes a connecting body and a connecting arm. The connecting body and the connecting arm are located within the receiving space. One end of the connecting arm is connected to the connecting body. The connecting body and the connecting arm are integrally formed. The electrode assembly is disposed within the receiving space. The electrode assembly includes a tab. Both the connecting body and the connecting arm are welded to the tab to form a solder mark.

[0005] In this embodiment of the battery cell, the terminal post includes an integrally formed connecting body and a connecting arm. The connecting body and the connecting arm can each provide welding positions for the tabs. The tabs are directly welded to the terminal post, thus eliminating the need for an adapter plate; the tabs do not need to be welded to the adapter plate before being welded to the terminal post. Eliminating the need for an adapter plate between the tabs and the terminal post reduces the number of components used and simplifies the structure of the battery cell. Furthermore, the saved space allows for increased volume of the electrode assembly, improving the energy density of the battery cell. Additionally, it reduces the internal resistance between the terminal post and the tab. In this embodiment of the battery cell, the sum of the areas of the connecting body and the connecting arm is relatively large, resulting in a relatively large connection area for the terminal post itself. The connecting body and the connecting arm can be welded to the tab simultaneously, which increases the welding area between the terminal post and the tab, increases the connection strength between the terminal post and the tab, and improves the current carrying capacity between the terminal post and the tab, thereby enhancing the safety of the battery cell.

[0006] In some feasible implementations, the solder mark includes a first sub-solder mark and a second sub-solder mark, the first sub-solder mark connecting the electrode tab and the connecting body, and a portion of the second sub-solder mark connecting the electrode tab and the connecting body, and another portion connecting the electrode tab and the connecting arm.

[0007] The first sub-weld stamp can utilize the welding surface of the connecting body, while the second sub-weld stamp can utilize the welding surfaces of both the connecting body and the connecting arm. Therefore, the method of simultaneously welding the electrode lug and the electrode post with the first and second sub-weld stamps can improve the utilization rate of the welding surfaces of the connecting body and the connecting arm, and increase the welding area between the electrode post and the electrode lug.

[0008] In some feasible embodiments, along the length of the end cap, the connecting body includes a first end and a second end opposite to each other. The first end is provided with two connecting arms. The battery cell includes two sets of electrode assemblies. One connecting arm is welded to the tab of one set of electrode assemblies, and the other connecting arm is welded to the tab of another set of electrode assemblies.

[0009] Both sets of electrode assemblies have their tabs welded to the connecting body, and each set of electrode assemblies has its tabs welded to a different connecting arm. The welding surface area of ​​the connecting body and the connecting arm is relatively large, and there can be a gap between the tabs of the two sets of electrode assemblies, so that the tabs of the two sets of electrode assemblies will not come into contact, reducing the possibility of positional interference caused by contact between the tabs of the two sets of electrode assemblies and affecting the welding quality.

[0010] In some feasible implementations, two connecting arms located at the first end are spaced apart along the width direction of the end cap, and the two connecting arms and the connecting body enclose and form a first groove.

[0011] The way the two connecting arms and the connecting body at the first end form a first groove allows for a reduction in the amount of material used in the electrode post while increasing the welding area between the electrode post and the electrode tab. This helps to reduce the overall weight of the battery cell and increase its energy density. Other structural components can be installed at the location where the two connecting arms and the connecting body at the first end form the first groove, allowing for reuse of the first groove and improving space utilization.

[0012] In some possible implementations, the first groove includes a first bottom wall and a first side wall, the first bottom wall being located on the connecting body and the first side wall being located on the connecting arm, both the first bottom wall and the first side wall being planar and perpendicular to the first bottom wall.

[0013] Along the length of the end cap, the opening of the first groove corresponds to the first bottom wall. The structural shape of the connecting body and the connecting arm is relatively regular, making it easy to process and manufacture, and reducing the difficulty of processing and manufacturing.

[0014] In some possible implementations, the first groove includes a first arcuate inner wall, a portion of which is located on one connecting arm and another portion on another connecting arm, with a smooth transition between the connecting arm and the connecting body.

[0015] A smooth transition between the connecting arm and the connecting body can improve the connection strength between them and reduce the possibility of stress concentration in the transition area, which could lead to cracks in the transition area.

[0016] In some possible implementations, the end cap includes an injection port facing a first recess that avoids the injection port.

[0017] The first groove avoids the injection hole, and the connecting arm will not block the injection hole. This ensures that the connecting arm will not increase the flow resistance of the electrolyte during the injection process, so that the electrolyte can be injected smoothly and the injection efficiency can be improved.

[0018] In some feasible implementations, the second end is provided with two connecting arms, the battery cell includes two sets of electrode assemblies, one connecting arm at the first end and one connecting arm at the second end are both welded to the tabs of one set of electrode assemblies, and the other connecting arm at the first end and the other connecting arm at the second end are both welded to the tabs of another set of electrode assemblies.

[0019] Both the first and second ends of the connecting body are provided with connecting arms, which can further increase the connection area between the electrode tab and the electrode post and improve the connection strength between the electrode tab and the electrode post.

[0020] In some feasible embodiments, two connecting arms located at the second end are spaced apart along the width direction of the end cap, and the two connecting arms and the connecting body enclose and form a second groove.

[0021] The way the two connecting arms and the connecting body at the second end form a second groove allows for a reduction in the amount of material used in the electrode post while increasing the welding area between the electrode post and the electrode tab. This helps to reduce the overall weight of the battery cell and increase its energy density. Other structural components can be installed at the location where the two connecting arms and the connecting body at the second end form the second groove, allowing for reuse of the second groove and improving space utilization.

[0022] In some possible implementations, the second groove includes a second bottom wall and a second side wall, the second bottom wall being located on the connecting body and the second side wall being located on the connecting arm, both the second bottom wall and the second side wall being planar and perpendicular to each other.

[0023] Along the length of the end cap, the opening of the second groove corresponds to the second bottom wall. The structural shape of the connecting body and the connecting arm is relatively regular, making it easy to process and manufacture, and reducing the difficulty of processing and manufacturing.

[0024] In some possible implementations, the second groove includes a second arcuate inner wall, a portion of which is located on one connecting arm and another portion on another connecting arm, with a smooth transition between the connecting arm and the connecting body.

[0025] A smooth transition between the connecting arm and the connecting body can improve the connection strength between them and reduce the possibility of stress concentration in the transition area, which could lead to cracks in the transition area.

[0026] In some feasible implementations, the length of the connecting arm disposed on the first end along the length direction of the end cap is greater than the length of the connecting arm disposed on the second end.

[0027] When the pole is installed on the end cap, the connecting arm on the first end can be relatively far away from the edge of the end cap, while the connecting arm on the second end can be relatively close to the edge of the end cap, thereby reducing the possibility of positional interference between the connecting arm on the second end and other structural components.

[0028] In some feasible embodiments, along the length of the end cap, the first sub-weld includes opposing first and second edges, the second sub-weld includes opposing third and fourth edges, the third edge is located on the connecting body, the fourth edge is located on the connecting arm, the length of the second sub-weld is greater than the length of the first sub-weld, the first edge is flush with the third edge, and there is a first gap between the second edge and the fourth edge.

[0029] In some feasible implementations, along the length of the end cap, the two ends of the second sub-weld extend beyond the first sub-weld, with a second gap between the first edge and the third edge, and a third gap between the second edge and the fourth edge.

[0030] In some feasible implementations, along the width direction of the end cap, the first sub-weld is located on the side of the second sub-weld away from the edge of the end cap.

[0031] When the electrode assembly moves within the housing, the tabs will bear tensile forces. Compared to the first sub-solder mark, the second sub-solder mark, which is closer to the edge of the end cap, can reduce the possibility of tearing or separation between the tab and the electrode post due to tensile forces.

[0032] In some feasible implementations, the first sub-solder and the second sub-solder are spaced apart.

[0033] The first and second sub-weld marks are set independently, which helps to increase the number of welding points between the electrode tab and the electrode post, and improve the connection strength between the electrode tab and the electrode post.

[0034] In some feasible embodiments, the battery cell includes an insulating plate disposed on an end cap, the insulating plate being located within a receiving space, the insulating plate including a third groove facing the electrode assembly, and a connecting body and a connecting arm being located within the third groove.

[0035] The connecting body and connecting arm are sunk into the insulating plate. The connecting body and connecting arm can reuse the third groove, improving space utilization. At the same time, the space occupied by the connecting body and connecting arm is reduced, which is conducive to improving the energy density of the battery cell.

[0036] This application provides a battery device that includes the aforementioned battery cell.

[0037] This application provides an electrical device including the battery device described above. The battery device is used to provide electrical energy. Attached Figure Description

[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0039] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0040] Figure 2 This is a partially exploded structural diagram of a battery device provided in an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of the structure of a battery module provided in one embodiment of the application;

[0042] Figure 4 This is a partially exploded structural diagram of a battery cell provided in an embodiment of this application;

[0043] Figure 5 This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0044] Figure 6 This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of the structure of a pole provided in an embodiment of this application;

[0046] Figure 8 This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0047] Figure 9This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0048] Figure 10 This is a partial structural schematic diagram of a pole provided in an embodiment of this application;

[0049] Figure 11 This is a partial structural schematic diagram of a pole provided in an embodiment of this application;

[0050] Figure 12 This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0051] Figure 13 for Figure 12 Enlarged view of the middle W section;

[0052] Figure 14 This is a partial structural diagram of a battery cell provided in one embodiment of this application;

[0053] Figure 15 for Figure 14 Enlarged view of point M in the middle;

[0054] Figure 16 This is a partial structural diagram of a battery cell provided in one embodiment of this application.

[0055] Explanation of reference numerals in the attached figures:

[0056] 1. Vehicle; 10. Battery unit; 10a. Housing; 10b. First housing section; 10c. Second housing section; 11. Controller; 12. Motor;

[0057] 20. Battery module;

[0058] 30. Battery cell;

[0059] 40. End cap; 41. Injection port;

[0060] 50. Shell;

[0061] 60. Electrode assembly; 61. Main body; 62. Electrode tab;

[0062] 70. Pole post;

[0063] 71. Connecting body; 711. First end; 712. Second end;

[0064] 72. Connect the outrigger;

[0065] 80. Solder mark; 81. First sub-solder mark; 811. First edge; 812. Second edge; 82. Second sub-solder mark; 821. Third edge; 822. Fourth edge;

[0066] 90. First groove; 91. First bottom wall; 92. First side wall; 93. First arc-shaped inner wall;

[0067] 100. Second groove; 101. Second bottom wall; 102. Second side wall; 103. Second arc-shaped inner wall;

[0068] 110. Insulating board; 111. Third groove; 112. Protective net;

[0069] 120. Pressure relief mechanism;

[0070] X, length direction;

[0071] Y, width direction. Detailed Implementation

[0072] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0073] It should be noted that, unless otherwise stated, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which the embodiments of this application pertain.

[0074] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and other indications of orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0075] Furthermore, technical terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise explicitly defined.

[0076] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0077] In the description of the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0078] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery device applications, market demand is also constantly increasing.

[0079] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0080] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. The battery device mentioned in this application can be a battery pack. For example, the battery device mentioned in this application can include battery modules, etc. A battery device generally includes a housing for encapsulating one or more battery cells. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0081] A single battery cell may include an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode plates.

[0082] The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive current collector includes a positive current collection section and a positive electrode tab connected to the current collection section. The positive current collection section is coated with the positive active material layer. The positive electrode tab is not coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum. The positive active material layer includes the positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0083] The negative electrode sheet 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. The negative electrode current collector includes a negative electrode current collection section and a negative electrode tab connected to the negative electrode current collection section. The negative electrode current collection section is coated with the negative electrode active material layer. The negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper. The negative electrode active material layer includes the negative electrode active material. The negative electrode active material can be carbon or silicon, etc.

[0084] The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0085] In related technologies, a battery cell includes terminals. The terminals are directly welded to the tabs of the electrode assembly. This direct welding method eliminates the need for adapters, reducing the number of components and simplifying the battery cell structure. Furthermore, the saved space allows for increased volume in the electrode assembly, improving the battery cell's energy density. Additionally, it reduces the internal resistance between the terminals and tabs. However, the welding area between the terminals and tabs is relatively small, potentially affecting the battery cell's safety due to insufficient welding area.

[0086] To alleviate the problem of insufficient welding area between the terminal and the tab, the area of ​​the terminal can be increased, which will help to increase the welding area between the terminal and the tab, increase the connection strength between the terminal and the tab, increase the current carrying capacity between the terminal and the tab, and improve the safety of the battery cell.

[0087] Based on the above considerations, to alleviate the problem of insufficient welding area between the terminal and the tab, the inventors, after in-depth research, designed a new battery cell. In this battery cell, the terminal includes a connecting body and a connecting arm. Both the connecting body and the connecting arm can provide welding positions for the tab. The connecting body and the connecting arm can be welded to the tab simultaneously, which helps to increase the welding area between the terminal and the tab, increase the connection strength between the terminal and the tab, improve the current carrying capacity between the terminal and the tab, and improve the safety of the battery cell.

[0088] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0089] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This application does not impose any special limitations on the above-mentioned electrical devices.

[0090] It should be understood that the technical solutions described in the embodiments of this application are not limited to the battery devices and electrical devices described above, but can also be applied to all battery devices including housings and electrical devices using battery devices. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0091] See Figure 1 As shown, vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 10 is installed inside vehicle 1. The battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1. For example, the battery device 10 can serve as the operating power source for vehicle 1. Vehicle 1 may also include a controller 11 and a motor 12. The controller 11 is used to control the battery device 10 to supply power to the motor 12. For example, this is for the power needs of vehicle 1 during starting, navigation, and driving.

[0092] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1.

[0093] To meet different power demands, the battery device 10 may include multiple battery cells. A battery cell is the smallest unit that makes up a battery module or battery pack. Multiple battery cells can be connected in series and / or in parallel via terminals for various applications. The battery device mentioned in this application includes a battery module or battery pack. Multiple battery cells can be connected in series, parallel, or a combination thereof. A combination thereof refers to a mix of series and parallel connections. In the embodiments of this application, multiple battery cells can be directly assembled into a battery pack, or they can first be assembled into a battery module, and then the battery module is assembled into a battery pack.

[0094] See Figure 2 As shown, the battery device 10 includes a housing 10a and individual battery cells (not shown). The individual battery cells are housed within the housing 10a.

[0095] The housing 10a can be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or it can be a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. This application embodiment does not limit this. The material of the housing 10a can be an alloy material such as aluminum alloy or iron alloy, or a polymer material such as polycarbonate or polyisocyanurate foam, or a composite material such as glass fiber and epoxy resin. This application embodiment also does not limit this.

[0096] The housing 10a is used to accommodate individual battery cells, and the housing 10a can have various structures. In some embodiments, the housing 10a may include a first housing portion 10b and a second housing portion 10c. The first housing portion 10b and the second housing portion 10c overlap each other. The first housing portion 10b and the second housing portion 10c together define a receiving space for accommodating the individual battery cells. The second housing portion 10c may be a hollow structure with one open end. In some embodiments, the first housing portion 10b is a plate-like structure. The first housing portion 10b overlaps the open side of the second housing portion 10c to form a housing 10a with a receiving space. In some embodiments, both the first housing portion 10b and the second housing portion 10c may also be hollow structures with one open side. The open side of the first housing portion 10b overlaps the open side of the second housing portion 10c to form a housing 10a with a receiving space. Of course, the first housing portion 10b and the second housing portion 10c can have various shapes, such as cylinders, cuboids, etc.

[0097] To improve the sealing performance after the first housing part 10b and the second housing part 10c are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 10b and the second housing part 10c.

[0098] In some embodiments, the first housing portion 10b covers the top of the second housing portion 10c. The first housing portion 10b may also be referred to as the upper housing cover, and the second housing portion 10c may also be referred to as the lower housing.

[0099] In the battery device 10, there can be one or more battery cells. When there are multiple battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel. Multiple battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within the housing 10a. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form a battery module. Multiple battery modules can then be connected in series, parallel, or in a mixed configuration to form a whole and housed within the housing 10a.

[0100] In some embodiments, see Figure 3 As shown, there can be multiple battery cells 30. Multiple battery cells 30 are first connected in series, parallel, or in a mixed connection to form a battery module 20. Multiple battery modules 20 are then connected in series, parallel, or in a mixed connection to form a whole, which is housed in the casing 10a.

[0101] Multiple battery cells 30 in the battery module 20 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 30 in the battery module 20.

[0102] In this embodiment, the battery cell 30 may include a lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and this embodiment is not limited thereto. The battery cell 30 may be flat, cuboid, or other shapes, and this embodiment is not limited thereto either. However, for the sake of brevity, the following embodiment uses a cuboid battery cell 30 as an example for illustration.

[0103] Battery cell 30 refers to the smallest unit that makes up battery device 10. See also Figure 4 As shown, the battery cell 30 includes an end cap 40, a housing 50, and an electrode assembly 60.

[0104] End cap 40 refers to a component that covers the opening of housing 50 to isolate the internal environment of battery cell 30 from the external environment. Exemplarily, the shape of end cap 40 can be adapted to the shape of housing 50 to fit the housing 50. Exemplarily, end cap 40 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 40 is not easily deformed under compression or impact, enabling battery cell 30 to have higher structural strength and improved safety performance. Functional components such as terminals 70 can be provided on end cap 40. Terminals 70 can be used for electrical connection with electrode assembly 60 for outputting or inputting electrical energy into battery cell 30.

[0105] In some embodiments, the end cap 40 may also be provided with a pressure relief mechanism 120 for releasing internal pressure when the internal pressure or temperature of the battery cell 30 reaches a threshold. The end cap 40 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating plate 110 may also be provided on the inner side of the end cap 40. The insulating plate 110 can be used to isolate the electrical connection components within the housing 50 from the end cap 40 to reduce the risk of short circuits. Exemplarily, the insulating plate 110 can be made of plastic, rubber, etc.

[0106] The housing 50 is a component used to cooperate with the end cap 40 to form the internal environment of the battery cell 30. The formed internal environment can accommodate the electrode assembly 60, electrolyte (not shown in the figure), and other components. The housing 50 and the end cap 40 can be independent components. An opening can be provided on the housing 50, and the end cap 40 closes the opening to form the internal environment of the battery cell 30. Alternatively, the end cap 40 and the housing 50 can be integrated. Specifically, the end cap 40 and the housing 50 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 50, the end cap 40 closes the housing 50. The housing 50 can be of various shapes and sizes, such as cuboid, hexagonal prism, etc. Specifically, the shape of the housing 50 can be determined according to the specific shape and size of the electrode assembly 60. The material of the housing 50 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment does not impose any special limitations on this.

[0107] Electrode assembly 60 is the component in the battery cell 30 where electrochemical reactions occur. The housing 50 may contain one or more electrode assemblies 60. The electrode assembly 60 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 61 of the electrode assembly 60. The portions of the positive and negative electrode sheets without active material each constitute a tab 62. The positive and negative tabs may be located together at one end of the main body 61 or at opposite ends of the main body 61. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs 62 connect to the terminals 70 to form a current loop.

[0108] See Figure 4 , Figure 5 and Figure 6 As shown, this application provides a battery cell 30, which includes an end cap 40, a housing 50, an electrode assembly 60, and a terminal post 70.

[0109] End cap 40 is connected to housing 50. End cap 40 and housing 50 form a receiving space. Electrode post 70 is disposed on end cap 40. Electrode post 70 includes connecting body 71 and connecting arm 72. Connecting body 71 and connecting arm 72 are located within the receiving space. One end of connecting arm 72 is connected to connecting body 71. Connecting body 71 and connecting arm 72 are integrally formed. Electrode assembly 60 is disposed within the receiving space. Electrode assembly 60 includes electrode tab 62. Connecting body 71 and connecting arm 72 are both welded to electrode tab 62 to form solder marks 80.

[0110] In some feasible implementations, the connecting arm 72 protrudes beyond the connecting body 71. The connecting arm 72 can be a cantilever beam structure.

[0111] In some implementations, the electrode assembly 60 includes a body portion 61 and tabs 62. The tabs 62 are connected to the body portion 61. The body portion 61 includes two opposing end faces. The two tabs 62 with different polarities can be led out from the same end face. Alternatively, the two tabs 62 with different polarities can be led out from two separate end faces.

[0112] In some feasible ways, both the connecting body 71 and the connecting arm 72 are welded to the tab 62 by ultrasonic welding or laser welding to form a weld mark 80.

[0113] In some feasible implementations, the end cap 40 can be a rectangular structure. The outer peripheral edge of the end cap 40 can be welded to the housing 50.

[0114] In some feasible implementations, the end cap 40 can be made of metal, such as copper, iron, aluminum, stainless steel, or aluminum alloy. An insulating component is provided between the terminal post 70 and the end cap 40 to isolate them. In some examples, the terminal post 70 can be a one-piece molded structure.

[0115] In some feasible embodiments, the tabs 62 of the electrode assembly 60 are welded to the connecting body 71 and the connecting arm 72. After the tabs 62 are welded to the connecting body 71 and the connecting arm 72, the electrode assembly 60 is installed into the housing 50. Then, the end cap 40 is connected to the housing 50.

[0116] In this embodiment, the battery cell 30 includes an integrally formed connecting body 71 and connecting arm 72. The connecting body 71 and connecting arm 72 provide welding positions for the tabs 62. The tabs 62 are directly welded to the terminal 70, eliminating the need for an adapter plate. The tabs 62 do not need to be welded to the adapter plate before being welded to the terminal 70. Eliminating the need for an adapter plate between the tabs 62 and the terminal 70 reduces the number of components and simplifies the structure of the battery cell 30. Furthermore, the saved space allows for an increase in the volume of the electrode assembly 60, thereby improving the energy density of the battery cell 30. Additionally, it reduces the internal resistance between the terminal 70 and the tabs 62. In this embodiment, the combined area of ​​the connecting body 71 and the connecting arm 72 of the terminal 70 is relatively large, resulting in a relatively large connection area for the terminal 70 itself. The connecting body 71 and the connecting arm 72 can be welded to the tab 62 at the same time, which helps to increase the welding area between the terminal 70 and the tab 62, increase the connection strength between the terminal 70 and the tab 62, and improve the overcurrent capacity between the terminal 70 and the tab 62, thereby helping to improve the safety of the battery cell 30.

[0117] In some feasible embodiments, the surface of the connecting body 71 facing the electrode assembly 60 is flush with the surface of the connecting arm 72 facing the electrode assembly 60. The surfaces of the connecting body 71 and the connecting arm 72 facing the electrode assembly 60 do not have a stepped structure, facilitating welding of the tab 62 to the connecting body 71 and the connecting arm 72.

[0118] See also some of the possible implementation methods. Figure 6 As shown, the solder mark 80 includes a first sub-solder mark 81 and a second sub-solder mark 82. The first sub-solder mark 81 connects the electrode tab 62 and the connecting body 71. A portion of the second sub-solder mark 82 connects the electrode tab 62 and the connecting body 71, and another portion connects the electrode tab 62 and the connecting support arm 72.

[0119] The first sub-solder mark 81 connects only the electrode tab 62 and the connecting body 71. The first sub-solder mark 81 is located on the connecting body 71. Part of the second sub-solder mark 82 is located on the connecting body 71, and part is located on the connecting arm 72.

[0120] The first sub-weld mark 81 can utilize the welding surface of the connecting body 71, while the second sub-weld mark 82 can utilize the welding surfaces of the connecting body 71 and the connecting arm 72. Therefore, the method of simultaneously welding the electrode lug 62 and the electrode post 70 with the first sub-weld mark 81 and the second sub-weld mark 82 can help improve the utilization rate of the welding surfaces of the connecting body 71 and the connecting arm 72, and increase the welding area between the electrode post 70 and the electrode lug 62.

[0121] See also some of the possible implementation methods. Figure 5 , Figure 6 and Figure 7 As shown, along the length direction X of the end cap 40, the connecting body 71 includes a first end 711 and a second end 712. The first end 711 is provided with two connecting arms 72. The battery cell 30 includes two sets of electrode assemblies 60. One connecting arm 72 is welded to the tab 62 of one set of electrode assemblies 60, and the other connecting arm 72 is welded to the tab 62 of the other set of electrode assemblies 60.

[0122] The battery cell 30 includes two sets of electrode assemblies 60, wherein each set of electrode assemblies 60 may include one or more electrode assemblies 60. This embodiment of the application illustrates an example where each set of electrode assemblies 60 includes one electrode assembly 60, and the battery cell 30's casing 50 contains a total of two electrode assemblies 60.

[0123] Both sets of electrode assemblies 60 have their tabs 62 welded to the connecting body 71, and each set of electrode assemblies 60 has its tabs 62 welded to a different connecting arm 72. The welding surface area of ​​the connecting body 71 and the connecting arm 72 is relatively large, and there can be a gap between the tabs 62 of the two sets of electrode assemblies 60, so that the tabs 62 of the two sets of electrode assemblies 60 will not come into contact, reducing the possibility of positional interference caused by contact between the tabs 62 of the two sets of electrode assemblies 60 and affecting the welding quality.

[0124] See also some of the possible implementation methods. Figure 5 , Figure 6 and Figure 7 As shown, along the width direction Y of the end cap 40, two connecting arms 72 are spaced apart at the first end 711, and the two connecting arms 72 and the connecting body 71 enclose and form a first groove 90. Along the length direction X of the end cap 40, the opening of the first groove 90 is away from the connecting body 71.

[0125] The two connecting arms 72 located at the first end 711 can be welded to the tabs 62 of the two sets of electrode assemblies 60 respectively. The two connecting arms 72 located at the first end 711 are spaced apart, which helps to reduce the possibility of contact between the tabs 62 of the two sets of electrode assemblies 60.

[0126] The arrangement of the two connecting arms 72 and the connecting body 71 at the first end 711 to form the first groove 90 allows for a reduction in the material usage of the electrode post 70 while increasing the welding area between the electrode post 70 and the electrode tab 62. This helps to reduce the overall weight of the battery cell 30 and increase its energy density. Other structural components can be installed at the location where the two connecting arms 72 and the connecting body 71 at the first end 711 form the first groove 90, allowing for reuse of the first groove 90 and improving space utilization.

[0127] See also some of the possible implementation methods. Figure 7 As shown, the first groove 90 includes a first bottom wall 91 and a first side wall 92. The first bottom wall 91 is located on the connecting body 71, and the first side wall 92 is located on the connecting support arm 72. The two connecting supports 72 located at the first end 711 each have a first side wall 92. Both the first bottom wall 91 and the first side wall 92 are planar, and the first side wall 92 is perpendicular to the first bottom wall 91.

[0128] Along the length direction X of the end cap 40, the opening of the first groove 90 is correspondingly provided with the first bottom wall 91. The structural shape of the connecting body 71 and the connecting arm 72 is relatively regular, which is easy to process and manufacture, reducing the difficulty of processing and manufacturing.

[0129] In some examples, the connecting body 71 can be rectangular. The connecting arm 72 can be rectangular. The two connecting arms 72 located at the first end 711 can be arranged parallel to each other.

[0130] See also some of the possible implementation methods. Figure 8 As shown, the first groove 90 includes a first arc-shaped inner wall 93. A portion of the first arc-shaped inner wall 93 is located on one connecting arm 72, and another portion is located on another connecting arm 72. The connecting arm 72 and the connecting body 71 have a smooth transition.

[0131] The smooth transition between the connecting arm 72 and the connecting body 71 can improve the connection strength between the connecting arm 72 and the connecting body 71, and reduce the possibility of stress concentration in the transition area between the connecting arm 72 and the connecting body 71, which could lead to cracks in the transition area.

[0132] In some examples, the first arc-shaped inner wall 93 can be a circular arc surface.

[0133] See in some examples Figure 8 As shown, the end cap 40 includes an injection hole 41. The injection hole 41 is disposed facing the first groove 90. The first groove 90 avoids the injection hole 41.

[0134] The injection hole 41 is used to inject electrolyte into the battery cell 30. After the electrolyte injection is completed, the injection hole 41 can be sealed using a sealing component. The first groove 90 avoids the injection hole 41, and the connecting arm 72 does not obstruct the injection hole 41, so that the connecting arm 72 does not increase the flow resistance of the electrolyte during the injection process, allowing the electrolyte to be injected smoothly and improving the injection efficiency.

[0135] See also some of the possible implementation methods. Figure 9 As shown, the second end 712 is provided with two connecting arms 72. The battery cell 30 includes two sets of electrode assemblies 60. One connecting arm 72 of the first end 711 and one connecting arm 72 of the second end 712 are both welded to the tabs 62 of one set of electrode assemblies 60. The other connecting arm 72 of the first end 711 and the other connecting arm 72 of the second end 712 are both welded to the tabs 62 of the other set of electrode assemblies 60.

[0136] Both the first end 711 and the second end 712 of the connecting body 71 are provided with connecting arms 72, which can further increase the connection area between the tab 62 and the pole post 70 and improve the connection strength between the tab 62 and the pole post 70. The connecting arms 72 provided at the first end 711 and the second end 712 of the connecting body 71 extend in opposite directions.

[0137] See in some examples Figure 9 and Figure 10As shown, along the width direction Y of the end cap 40, two connecting arms 72 located at the second end 712 are spaced apart, and the two connecting arms 72 and the connecting body 71 enclose and form a second groove 100. Along the length direction X of the end cap 40, the opening of the second groove 100 is away from the connecting body 71.

[0138] The two connecting arms 72 located at the first end 711 and the two connecting arms 72 located at the second end 712 can be welded to the tabs 62 of the two sets of electrode assemblies 60 respectively. The two connecting arms 72 located at the second end 712 are spaced apart, which can help reduce the possibility of contact between the tabs 62 of the two sets of electrode assemblies 60.

[0139] The way the two connecting arms 72 and the connecting body 71 at the second end 712 enclose and form the second groove 100 is beneficial for reducing the amount of material used in the electrode post 70 while increasing the welding area between the electrode post 70 and the electrode tab 62. This helps to reduce the overall weight of the battery cell 30 and increase its energy density. Other structural components can be installed at the location where the two connecting arms 72 and the connecting body 71 at the second end 712 enclose and form the second groove 100 to reuse the second groove 100 and improve space utilization.

[0140] See in some examples Figure 10 As shown, the second groove 100 includes a second bottom wall 101 and a second side wall 102. The second bottom wall 101 is located on the connecting body 71, and the second side wall 102 is located on the connecting support arm 72. The two connecting supports 72 located at the second end 712 each have a second side wall 102. Both the second bottom wall 101 and the second side wall 102 are planar, and the second side wall 102 is perpendicular to the second bottom wall 101.

[0141] Along the length direction X of the end cap 40, the opening of the second groove 100 is correspondingly provided with the second bottom wall 101. The structural shape of the connecting body 71 and the connecting arm 72 is relatively regular, which is easy to process and manufacture, reducing the difficulty of processing and manufacturing.

[0142] In some examples, the connecting body 71 can be rectangular. The connecting arm 72 can be rectangular. The two connecting arms 72 located at the second end 712 can be arranged parallel to each other.

[0143] See in some examples Figure 11 As shown, the second groove 100 includes a second arcuate inner wall 103. A portion of the second arcuate inner wall 103 is located on one connecting arm 72, and another portion is located on another connecting arm 72. The connecting arm 72 and the connecting body 71 have a smooth transition.

[0144] The smooth transition between the connecting arm 72 and the connecting body 71 can improve the connection strength between the connecting arm 72 and the connecting body 71, and reduce the possibility of stress concentration in the transition area between the connecting arm 72 and the connecting body 71, which could lead to cracks in the transition area.

[0145] In some examples, the first arc-shaped inner wall 93 can be a circular arc surface.

[0146] In some examples, along the length direction X of the end cap 40, a first groove 90 and a second groove 100 are respectively provided on opposite sides of the connecting body 71.

[0147] In some examples, along the length direction X of the end cap 40, the length of the connecting arm 72 disposed on the first end 711 is greater than the length of the connecting arm 72 disposed on the second end 712.

[0148] The connecting arm 72 disposed on the first end 711 extends along the length direction X of the end cover 40. The connecting arm 72 disposed on the second end 712 extends along the length direction X of the end cover 40. When the pole post 70 is disposed on the end cover 40, the connecting arm 72 on the first end 711 can be relatively far away from the edge of the end cover 40, while the connecting arm 72 on the second end 712 can be relatively close to the edge of the end cover 40, thereby reducing the possibility of positional interference between the connecting arm 72 on the second end 712 and other structural components.

[0149] See in some examples Figure 12 and Figure 13 As shown, along the length direction X of the end cap 40, the first sub-solder mark 81 includes opposing first edges 811 and second edges 812, and the second sub-solder mark 82 includes opposing third edges 821 and fourth edges 822. The third edge 821 is located on the connecting body 71, and the fourth edge 822 is located on the connecting arm 72. Along the length direction X of the end cap 40, the length of the second sub-solder mark 82 is greater than the length of the first sub-solder mark 81. The first edge 811 is flush with the third edge 821, and there is a first gap L1 between the second edge 812 and the fourth edge 822.

[0150] Along the length direction X of the end cap 40, one end of the second sub-weld 82 extends beyond the first sub-weld 81, while the other end does not extend beyond the first sub-weld 81. The end of the second sub-weld 82 that extends beyond the first sub-weld 81 can be located at the connecting arm 72. The end of the second sub-weld 82 that extends beyond the first sub-weld 81 is connected to the electrode tab 62 and the connecting arm 72.

[0151] For example, a connecting arm 72 is provided at the first end 711 of the connecting body 71, while no connecting arm 72 is provided at the second end 712 of the connecting body 71. A first sub-solder mark 81 is located on the connecting body 71. A portion of the second sub-solder mark 82 is located on the connecting body 71, and another portion is located on the connecting arm 72 at the first end 711.

[0152] See in some examples Figure 14 and Figure 15 As shown, along the length direction X of the end cap 40, the first sub-weld 81 includes opposing first edges 811 and second edges 812, and the second sub-weld 82 includes opposing third edges 821 and fourth edges 822. The third edge 821 is located on the connecting body 71, and the fourth edge 822 is located on the connecting arm 72. Along the length direction X of the end cap 40, the length of the second sub-weld 82 is greater than the length of the first sub-weld 81. Along the length direction X of the end cap 40, both ends of the second sub-weld 82 extend beyond the first sub-weld 81. Along the length direction X of the end cap 40, one end of the second sub-weld 82 extends beyond the first sub-weld 81, and the other end also extends beyond the first sub-weld 81. There is a second distance L2 between the first edge 811 and the third edge 821, and a third distance L3 between the second edge 812 and the fourth edge 822.

[0153] For example, both the first end 711 and the second end 712 of the connecting body 71 are provided with connecting arms 72. A first sub-solder mark 81 is located on the connecting body 71. The middle portion of the second sub-solder mark 82 is located on the connecting body 71, with one end of the second sub-solder mark 82 located on the connecting arm 72 on the first end 711 and the other end located on the connecting arm 72 on the second end 712.

[0154] In some examples, along the width direction Y of the end cap 40, the first sub-weld 81 is located on the side of the second sub-weld 82 away from the edge of the end cap 40.

[0155] The length of the second sub-weld mark 82 is greater than the length of the first sub-weld mark 81. The length of the welding area formed by the tab 62 and the pole post 70 through the second sub-weld mark 82 is greater than the length of the welding area formed by the tab 62 and the pole post 70 through the first sub-weld mark 81.

[0156] When the electrode assembly 60 moves within the housing 50, the tab 62 will bear a tensile force. Compared to the first sub-solder mark 81, the second sub-solder mark 82 is closer to the edge of the end cap 40, which can reduce the possibility of tearing or separation between the tab 62 and the electrode post 70 due to the tensile force on the tab 62.

[0157] In some examples, the first sub-weld 81 is connected to the second sub-weld 82. The first sub-weld 81 and the second sub-weld 82 are formed simultaneously in one welding operation.

[0158] In some examples, the first sub-solder mark 81 and the second sub-solder mark 82 are spaced apart. There is a gap between the first sub-solder mark 81 and the second sub-solder mark 82.

[0159] The first sub-weld mark 81 and the second sub-weld mark 82 are set independently, which helps to increase the number of welding points between the tab 62 and the pole post 70 and improve the connection strength between the tab 62 and the pole post 70.

[0160] For example, the first sub-weld mark 81 and the second sub-weld mark 82 can be formed by two welding processes.

[0161] See also some of the possible implementation methods. Figure 16 As shown, the battery cell 30 includes an insulating plate 110. The insulating plate 110 is disposed on the end cap 40. The insulating plate 110 is located within a receiving space. The insulating plate 110 includes a third groove 111. The third groove 111 faces the electrode assembly 60. The connecting body 71 and the connecting arm 72 are located within the third groove 111.

[0162] The insulating plate 110 can isolate the electrode assembly 60 and the end cap 40. The insulating plate 110 can press against the electrode assembly 60, reducing the possibility of the electrode assembly 60 shifting within the housing 50. The third groove 111 of the insulating plate 110 faces the electrode assembly 60. The connecting body 71 and the connecting arm 72 are located between the insulating plate 110 and the electrode assembly 60.

[0163] The connecting body 71 and the connecting arm 72 are lowered into the insulating plate 110. The connecting body 71 and the connecting arm 72 can reuse the third groove 111, improving space utilization and reducing the space occupied by the connecting body 71 and the connecting arm 72, which is beneficial to improving the energy density of the battery cell 30.

[0164] See in some examples Figure 4 and Figure 16 As shown, a pressure relief mechanism 120 is provided on the end cap 40. The insulating plate 110 includes a protective mesh 112. The protective mesh 112 is provided correspondingly to the pressure relief mechanism 120. The protective mesh 112 is provided in the middle area of ​​the insulating plate 110 along the length direction X of the end cap 40. The first end 711 of the connecting body 71 faces the protective mesh 112, and the second end 712 faces away from the protective mesh 112.

[0165] For example, the pressure relief mechanism 120 includes an explosion-proof valve, a balance valve, a gas valve, a pressure relief valve, or a safety valve.

[0166] According to some embodiments of this application, this application also provides a battery device 10, including a battery cell 30 of any of the above schemes.

[0167] According to some embodiments of this application, this application also provides an electrical device including a battery device 10 of any of the above-described embodiments, and the battery device 10 is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize the battery device 10.

[0168] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The application relates to a battery cell, which comprises the following parts: a shell; an end cover connected to the shell, the end cover and the shell forming a containing space; a pole column arranged on the end cover, the pole column comprising a connecting body and a connecting branch, the connecting body and the connecting branch being located in the containing space, one end of the connecting branch being connected to the connecting body, the connecting body and the connecting branch being integrally formed; an electrode assembly arranged in the containing space, the electrode assembly comprising a tab, the connecting body and the connecting branch being welded to the tab and forming a welding mark.

2. The battery cell of claim 1, wherein, The welding mark comprises a first sub-welding mark and a second sub-welding mark, the first sub-welding mark connecting the tab and the connecting body, and a part of the second sub-welding mark connecting the tab and the connecting body and another part connecting the tab and the connecting branch.

3. The battery cell of claim 2, wherein, Along the length direction of the end cover, the connecting body comprises opposite first and second ends, the first end is provided with two connecting branches, and the battery cell comprises two groups of electrode assemblies, one connecting branch is welded to the tab of one group of electrode assemblies, and the other connecting branch is welded to the tab of the other group of electrode assemblies.

4. The battery cell of claim 3, wherein, Along the width direction of the end cover, the two connecting branches at the first end are arranged at intervals, and the two connecting branches and the connecting body form a first groove.

5. The battery cell of claim 4, wherein, The first groove comprises a first bottom wall and a first side wall, the first bottom wall is located on the connecting body, the first side wall is located on the connecting branch, the first bottom wall and the first side wall are both planes, and the first side wall is perpendicular to the first bottom wall; or The first groove comprises a first arc-shaped inner wall, a part of the first arc-shaped inner wall is located on one connecting branch, and another part of the first arc-shaped inner wall is located on the other connecting branch, and the connecting branch and the connecting body are smoothly connected. The end cover comprises a liquid injection hole, the liquid injection hole is arranged to face the first groove, and the first groove avoids the liquid injection hole.

6. The battery cell according to claim 4 or 5, characterized in that The second end is provided with two connecting branches, the battery cell comprises two groups of electrode assemblies, one connecting branch at the first end and one connecting branch at the second end are both welded to the tab of one group of electrode assemblies, and the other connecting branch at the first end and the other connecting branch at the second end are both welded to the tab of the other group of electrode assemblies.

7. The battery cell of any one of claims 4 to 6, wherein, Along the width direction of the end cover, the two connecting branches at the second end are arranged at intervals, and the two connecting branches and the connecting body form a second groove.

8. The battery cell of claim 7, wherein, The second groove comprises a second bottom wall and a second side wall, the second bottom wall is located on the connecting body, the second side wall is located on the connecting branch, the second bottom wall and the second side wall are both planes, and the second side wall is perpendicular to the second bottom wall; or 9. The battery cell of claim 8, wherein, The second groove comprises a second arc-shaped inner wall, a part of the second arc-shaped inner wall is located on one connecting branch, and another part of the second arc-shaped inner wall is located on the other connecting branch, and the connecting branch and the connecting body are smoothly connected. ​ 10. The battery cell of any one of claims 7 to 9, wherein, The length of the connecting arm disposed on the first end is greater than the length of the connecting arm disposed on the second end along the length direction of the end cover.

11. The battery cell of any one of claims 3 to 10, wherein, Along the length direction of the end cover, the first sub-welding mark includes opposite first and second edges, and the second sub-welding mark includes opposite third and fourth edges, the third edge is located on the connecting body, and the fourth edge is located on the connecting arm, the length of the second sub-welding mark is greater than the length of the first sub-welding mark, the first edge is flush with the third edge, and the second edge has a first spacing from the fourth edge; or, Along the length direction of the end cover, the two ends of the second sub-welding mark respectively extend beyond the first sub-welding mark, the first edge has a second spacing from the third edge, and the second edge has a third spacing from the fourth edge.

12. The battery cell of claim 11, wherein, Along the width direction of the end cover, the first sub-welding mark is located on the side of the second sub-welding mark away from the edge of the end cover.

13. The battery cell of claim 12, wherein, The first sub-welding mark and the second sub-welding mark are spaced apart.

14. The battery cell of any one of claims 1 to 13, wherein, The battery monomer includes an insulating plate, the insulating plate is disposed on the end cover, the insulating plate is located in the containing space, the insulating plate includes a third groove, the third groove faces the electrode assembly, and the connecting body and the connecting arm are located in the third groove.

15. A battery device characterized by comprising: The battery monomer includes an insulating plate, the insulating plate is disposed on the end cover, the insulating plate is located in the containing space, the insulating plate includes a third groove, the third groove faces the electrode assembly, and the connecting body and the connecting arm are located in the third groove.

16. An electrical device, comprising: The battery device includes the battery monomer, and the battery device is used for providing electric energy.

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