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

Abstract

The application provides a battery monomer, a battery device, a power utilization equipment and an energy storage device, and belongs to the battery field. The battery monomer comprises a shell, an electrode assembly, an electrode terminal and a pressure relief part. The shell has a first end wall, and the first end wall is provided with an electrode lead-out hole. The electrode assembly is accommodated in the shell, and the electrode assembly has a first tab and a second tab with opposite polarities, and the second tab is electrically connected with the first end wall. The electrode terminal is arranged in the electrode lead-out hole and connected with the first tab. The electrode terminal has a ring structure and an inner hole. The pressure relief part is connected with the electrode terminal through a ring-shaped weak part, the ring-shaped weak part is arranged along the circumference of the inner hole, the pressure relief part seals the inner hole, and the ring-shaped weak part is configured to be cracked when the battery monomer is relieved. In the scheme, the pressure relief part is arranged by using part of the area occupied by the electrode terminal, the pressure relief part does not additionally occupy the first end wall, and the problem that the pressure relief capacity and the overcurrent capacity of the battery monomer conflict can be relieved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, electrical equipment, and energy storage device. Background Technology

[0002] Energy conservation and emission reduction are crucial for sustainable social development. Batteries, with their ability to store or release energy as needed, are widely used in various electrical devices and energy storage systems, and are an important component in promoting energy transition and sustainable development. For the new energy industry, battery technology is a critical factor in its development.

[0003] A single battery cell typically includes an electrode assembly, electrode terminals, a casing, and a pressure relief mechanism. The electrode assembly is electrically connected to the outside environment via the electrode terminals, and the pressure relief mechanism is used to release the internal pressure of the battery cell. However, existing battery cells often struggle to balance pressure relief capacity and overcurrent capacity. Utility Model Content

[0004] This application aims to at least solve one of the technical problems existing in the background art. To this end, one object of this application is to provide a battery cell, battery device, electrical device, and energy storage device that can alleviate the problem of conflict between the pressure relief capacity and overcurrent capacity of a battery cell.

[0005] An embodiment of the first aspect of this application provides a battery cell, including: a housing, an electrode assembly, electrode terminals, and a pressure relief portion. The housing has a first end wall with an electrode lead-out hole. The electrode assembly is housed within the housing and has a first tab and a second tab with opposite polarities. The second tab is electrically connected to the first end wall. The electrode terminals are located in the electrode lead-out hole and connected to the first tab. The electrode terminals have an annular structure and an inner hole. The pressure relief portion is connected to the electrode terminals through an annular weak portion. The annular weak portion is arranged circumferentially along the inner hole, and the pressure relief portion seals the inner hole. The annular weak portion is configured to crack when the battery cell is depressurized.

[0006] In the technical solution of this application embodiment, the electrode terminal is set as an annular structure with an inner hole, and a pressure relief part is provided and connected to the electrode terminal through an annular weak part. The annular weak part is arranged along the circumference of the inner hole and is configured to crack when the battery cell is depressurized to open the inner hole, thereby realizing pressure relief. In the battery cell of this embodiment, the orthographic projection of the electrode terminal along the axial direction of the electrode assembly on the first end wall partially overlaps with the orthographic projection of the pressure relief part along the axial direction of the electrode assembly on the first end wall. The pressure relief part does not occupy the first end wall additionally, thus improving the area utilization rate of the first end wall and alleviating the conflict caused by the electrode terminal and the pressure relief part each occupying part of the area of ​​the first end wall, which cannot simultaneously meet the overcurrent and pressure relief requirements. The battery cell of this embodiment can take into account both overcurrent capacity and pressure relief capacity.

[0007] In some embodiments, the annular weak portion is sealed to the wall of the inner hole, and the annular weak portion is disposed around the outer periphery of the pressure relief portion; the housing also includes a second end wall, the second end wall being opposite to the first end wall along the axial direction of the electrode assembly; the orthographic projection of the pressure relief portion along the axial direction of the electrode assembly onto the second end wall falls within the orthographic projection of the inner hole along the axial direction of the electrode assembly onto the second end wall.

[0008] Using this technical solution, if the annular weak part of the battery cell in this embodiment cracks when its internal pressure or temperature reaches a threshold, and the inner hole opens in a local position, since the annular weak part and the pressure relief part are located inside the inner hole, the high-temperature and high-pressure material can be discharged to the outside of the outer casing through the inner hole without changing the flow direction, which can have a positive effect on improving the smoothness of pressure relief.

[0009] In some embodiments, the pressure relief portion is located on the side of the electrode terminal opposite to the electrode assembly along the axial direction of the electrode assembly, and the annular weak portion is connected to the periphery of the inner hole.

[0010] In this technical solution, the annular weak section and the pressure relief section are located outside the inner hole. Thus, when the pressure relief section is welded to the electrode terminal using laser welding, and the welded joint serves as the annular weak section, the laser is less likely to directly strike the electrode assembly during the welding process because the annular weak section and the pressure relief section are located outside the inner hole, reducing the possibility of laser damage to the electrode assembly.

[0011] In some embodiments, the housing further includes a second end wall, which is opposite to the first end wall along the axial direction of the electrode assembly; the orthographic projection of the pressure relief portion along the axial direction of the electrode assembly onto the second end wall coincides with the orthographic projection of the inner hole along the axial direction of the electrode assembly onto the second end wall.

[0012] In some embodiments, the pressure relief portion is welded to the electrode terminal to form a welded portion, and the welded portion is formed as an annular weak portion.

[0013] In this embodiment, the welded portion is formed as a ring-shaped weak portion, which eliminates the need for additional processing steps to form the ring-shaped weak portion, thus simplifying the processing technology.

[0014] In some embodiments, the battery cell further includes a first current collector located between the electrode assembly and the electrode terminal along the axial direction of the electrode assembly. The first tab is connected to the electrode terminal through the first current collector. The first current collector has a through hole that is opposite to and communicates with the inner hole.

[0015] By providing a through hole in the first current collector located between the electrode assembly and the electrode terminal, the first current collector will not obstruct the high-temperature and high-pressure material, thus ensuring that pressure relief can be achieved.

[0016] In some embodiments, the inner hole is a liquid injection hole for injecting electrolyte into the casing, and / or the inner hole is a formation vent hole for venting air during the formation of the battery cell.

[0017] With this technical solution, the inner hole can be reused as a liquid injection hole and / or a formation vent hole. In this way, there is no need to open additional liquid injection holes and / or formation vent holes on the first end wall. The flow area between the first end wall and the busbar component can be larger, which is beneficial to improving the flow capacity of the battery cell.

[0018] In some embodiments, the housing is cylindrical with a cross section perpendicular to the axial direction of the electrode assembly. The pressure relief portion, the cross section of the electrode terminal, and the first end wall are all circular and coaxially arranged.

[0019] An embodiment of the second aspect of this application provides a battery device comprising a plurality of battery cells as described in the above embodiments.

[0020] In some embodiments, the battery device further includes a busbar component, which includes two connected busbars, each corresponding to one of the two battery cells; at least one busbar is electrically connected to the electrode terminals of the corresponding battery cell, and the orthographic projection of at least one busbar along the axial direction of the electrode assembly onto the first end wall does not overlap with the orthographic projection of the inner hole, pressure relief portion, and annular weak portion of the corresponding battery cell along the axial direction of the electrode assembly onto the first end wall; and / or, at least one busbar is electrically connected to the first end wall of the corresponding battery cell, and the orthographic projection of at least one busbar along the axial direction of the electrode assembly onto the first end wall does not overlap with the orthographic projection of the electrode terminals, pressure relief portion, and annular weak portion of the corresponding battery cell along the axial direction of the electrode assembly onto the first end wall.

[0021] Using this technical solution, multiple battery cells are connected in series, parallel, or mixed connections through a busbar assembly. Furthermore, the busbar assembly as a whole does not obstruct the inner bore, pressure relief section, or annular weak point, ensuring that it does not impede the discharge of high-temperature, high-pressure materials and allowing the battery cells to release pressure smoothly.

[0022] In some embodiments, both busbars are annular, and each busbar is adapted to the shape of the corresponding electrode terminal or the corresponding first end wall.

[0023] Compared with the technical solution where the orthographic projection shape of the busbar along the axial direction of the electrode assembly on the first end wall is not closed, in this embodiment both busbars are annular, and the area of ​​the busbars is larger, which can improve the current carrying capacity of the battery cell.

[0024] An embodiment of the third aspect of this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0025] An embodiment of the fourth aspect of this application provides an energy storage device that includes the battery device described above, the battery device being capable of storing and providing electrical energy.

[0026] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0027] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0028] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0029] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0030] Figure 3 This is a schematic diagram of the connection between a battery cell and a busbar component in some embodiments of this application;

[0031] Figure 4 This is a schematic diagram of the structure of the electrode assembly in some embodiments of this application;

[0032] Figure 5 This is a schematic diagram of the connection between a battery cell and a busbar component, omitting the pressure relief section and electrode terminals, according to some embodiments of this application.

[0033] Figure 6 for Figure 5 The diagram shows the exploded structure of the battery cell and the busbar component.

[0034] Figure 7 This is a schematic cross-sectional view of a battery cell according to some embodiments of this application;

[0035] Figure 8 for Figure 7 A magnified view of a portion of point A in the middle;

[0036] Figure 9 This is a cross-sectional schematic diagram of a battery cell according to other embodiments of this application;

[0037] Figure 10 for Figure 9 A magnified view of a portion of point B in the middle;

[0038] Figure 11 This is a top view of a battery cell according to some embodiments of this application;

[0039] Figure 12 This is a top view schematic diagram of a busbar component according to some embodiments of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1000 vehicles;

[0042] Battery unit 100, controller 200, motor 300;

[0043] Battery cell assembly 10, battery cell 11, housing 110, end cap 111, housing 112, peripheral sidewall 1121, first endwall 1122, electrode lead hole 1123, first current collector 1124, through hole 1125, second current collector 1126, electrode assembly 120, first tab 121, electrode body 122, positive current collector 1221, positive electrode body area 1221a, positive electrode blank area 1221b, negative current collector 1222, negative electrode body area 1222a, negative electrode blank area 1222b, separator 123, electrode terminal 130, body part 131, first flange part 132, second flange part 133, inner hole 134, pressure relief part 140, annular weak part 150, first insulating part 160, second insulating part 170, sealing ring 180;

[0044] Box 20, first box 21, second box 22;

[0045] Busbar component 30, busbar part 31, center hole 311, conductive connector 32. Detailed Implementation

[0046] 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.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0048] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0049] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0050] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0051] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0052] 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," and "circumferential" indicate the orientation or positional relationship 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.

[0053] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation", "connection", "linking", 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 connection of two components or the interaction between two components.

[0054] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0055] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0056] Currently, the application of rechargeable batteries is becoming increasingly widespread, judging from market trends. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in various electronic devices, such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application areas of rechargeable batteries continue to expand, the market demand is also constantly increasing.

[0057] In some related technologies, the top of a battery cell leads out current, while the bottom provides pressure relief; that is, the pressure relief mechanism and the current lead are located at different ends of the battery cell. Specifically, the top of the battery cell's casing has electrode terminals, which are electrically connected to the load via a busbar. The bottom of the casing has a pressure relief mechanism, which is used to open when the internal pressure or temperature of the battery cell reaches a threshold, thereby releasing the internal pressure of the battery cell. When using this battery cell to form the power system of an electrical device, in order to ensure that the internal pressure of the battery cell can be released smoothly, the electrical device needs to reserve a pressure relief space below the battery device composed of this battery cell. This is not conducive to achieving a compact design of the electrical device, and the pressure relief space below the battery cell cannot accommodate other functional structures.

[0058] In view of this, some related technologies propose placing an explosion-proof plate at the top of the battery cell, with the explosion-proof plate and electrode terminals spaced apart at the top of the battery cell. In such a battery cell, due to the limited area at the top of the cell, if priority is given to ensuring the current-carrying area between the battery cell and the busbar, the usable area of ​​the explosion-proof plate is insufficient, leading to poor pressure relief. Conversely, if priority is given to ensuring the pressure relief area of ​​the explosion-proof plate, the current-carrying area between the battery cell and the busbar is insufficient to meet the current requirements. Especially under high-current charging and discharging conditions, the connection point between the battery cell and the busbar heats up severely, potentially causing the busbar to melt and, in severe cases, even directly causing thermal runaway of the battery cell. In other words, this type of battery cell cannot simultaneously achieve both pressure relief capacity and current-carrying capacity.

[0059] To address at least one of the aforementioned technical problems, this application proposes an optimization and improvement of the battery cell. The proposed battery cell features an inner hole at the electrode terminals, and a pressure relief section connected to the electrode terminals via an annular weak portion. When the battery cell is depressurized, at least a portion of the annular weak portion cracks, allowing the inner hole to communicate with the outside, thus achieving pressure relief.

[0060] In such a battery cell, the pressure relief section is arranged using part of the area occupied by the electrode terminals. The pressure relief section does not occupy the first end wall. This can help reduce the encroachment of the pressure relief area on the current flow area, thereby alleviating the conflict between the current flow demand and the pressure relief demand of the battery cell.

[0061] The battery devices described in this application can be used, but are not limited to, in electrical equipment or energy storage devices such as vehicles, ships, or aircraft. A power system comprising the battery cells and battery devices described in this application can be used to construct such electrical equipment or energy storage devices.

[0062] The energy storage device utilizing a battery as a power system in this application embodiment can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems, etc. The energy storage device can store electrical energy as needed and output it at appropriate times. For example, the energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage device provided in this application embodiment can be used in any power system that requires energy storage.

[0063] In some embodiments, the energy storage device is an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0064] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet. Each battery cluster may include multiple battery units connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, these clusters are connected in parallel to increase the capacity of the energy storage device.

[0065] In this application embodiment, the electrical devices using battery devices as power sources can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, aircraft, robots, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.; and aircraft can include drones, etc.

[0066] It should be understood that the technical solutions described in the embodiments of this application are not limited to the battery devices and electrical equipment described above, but can also be applied to all battery devices including housings and electrical equipment using battery devices. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0067] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 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 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0068] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0069] Figure 2 An exploded structural diagram of a battery device 100 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies 10 for providing voltage and capacity. The battery cell assembly 10 may include multiple battery cells 11, which are connected in series, parallel, or mixed connection via a busbar.

[0070] In some embodiments, the battery cell assembly 10 is typically formed by arranging a plurality of battery cells 11.

[0071] As an example, the battery cell assembly 10 can be a battery module, which is formed by arranging and fixing multiple battery cells 11 together to form an independent module. As an example, the battery module can be formed by bundling multiple battery cells 11 together with cable ties.

[0072] In some embodiments, such as Figure 2As shown, the battery device 100 can be a battery pack, which includes a housing 20 and one or more individual battery cells 10, with the individual battery cells 10 housed within the housing 20. The housing 20 can be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or a complex three-dimensional structure composed of combinations of simple cuboids, cylinders, or spheres. The material of the housing 20 can be an alloy such as aluminum alloy or iron alloy, a polymer such as polycarbonate or polyisocyanurate foam, or a composite material such as glass fiber and epoxy resin.

[0073] As an example, the battery cell assembly 10 can be a battery module, and the battery cell assembly 10 can be housed in the housing 20 by fixing the battery module in the housing 20.

[0074] As an example, the battery cell assembly 10 can also be housed in the housing 20 by directly fixing multiple battery cells 11 to the housing 20.

[0075] As an example, the housing 20 may include a first housing 21 and a second housing 22. The first housing 21 and the second housing 22 are fastened together to form a closed space inside the housing 20 to house the battery cell assembly 10. Here, "closed" refers to covering or closing, and can be either non-sealed or sealed to prevent liquids or other foreign objects from affecting the charging or discharging of the battery cell 11. The first housing 21 may be a top cover or a bottom plate.

[0076] As an example, the housing 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 20 forms an enclosed space to accommodate the battery cell assembly 10.

[0077] In some embodiments, the housing 20 may be part of the vehicle's chassis structure. For example, a portion of the housing 20 may be at least a portion of the vehicle's floor, or a portion of the housing 20 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0078] The battery cell 11 provided in the embodiments of this application can be a secondary battery. A secondary battery refers to a battery cell 11 that can be used again after being discharged by recharging to activate the active material.

[0079] The battery cell 11 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited to this. As an example, the battery cell 11 can be a cylindrical battery cell, a prismatic battery cell, or a battery cell 11 of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells, etc., and this application has no particular limitation.

[0080] Figure 3 This is a schematic diagram of the connection between a battery cell and a busbar component in some embodiments of this application, such as... Figure 3 As shown, the battery cell 11 provided in the embodiments of this application includes a casing 110, an electrode assembly, and an electrolyte. The electrode assembly is the component in the battery cell 11 where an electrochemical reaction occurs. The electrode assembly and the electrolyte are housed within the casing 110. As an example, the electrolyte may be liquid, gel-like, or solid.

[0081] As an example, the housing 110 includes a housing 112 and an end cap 111. The housing 112 has an opening, and the end cap 111 closes to the opening of the housing 112. The housing 112 and the end cap 111 together enclose a mounting cavity, which provides mounting space for components such as electrode assemblies.

[0082] The housing 112 is a component used to cooperate with the end cap 111 to form the internal environment of the battery cell 11, wherein the formed internal environment can be used to accommodate electrode components, electrolyte, and other components. The housing 112 and the end cap 111 can be independent components. The housing 112 has an opening, and the end cap 111 closes the opening to form the internal environment of the battery cell 11. Alternatively, the end cap 111 and the housing 112 can be integrated. Specifically, the end cap 111 and the housing 112 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 112, the end cap 111 closes the housing 112. The housing 112 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 112 can be determined according to the specific shape and size of the electrode components. The material of the housing 112 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.

[0083] The housing 112 may be open at one end or at both ends. In some examples, the housing 112 may be a structure with an opening on one side, with an end cap 111 provided and covering the housing 112. In embodiments where the housing 112 is an opening on one side, the housing 112 specifically includes a peripheral sidewall 1121 and an end wall. The peripheral sidewall 1121 is connected around the end wall, and the end cap 111 is sealingly connected to the opening of the peripheral sidewall 1121 away from the end wall. In some examples, the peripheral sidewall 1121 and the end wall may be manufactured using integral molding processes such as stamping or integral casting. In other examples, the peripheral sidewall 1121 and the end wall may also be formed independently and connected as a whole by bonding, snap-fitting, welding, or other methods.

[0084] In other examples, the housing 112 may also be a structure with openings on both sides, and two end caps 111 are provided, with the two end caps 111 respectively covering the two openings of the housing 112.

[0085] End cap 111 refers to a component that covers the opening of housing 112 to isolate the internal environment of battery cell 11 from the external environment. The shape of end cap 111 can be adapted to the shape of housing 112 to fit it. Optionally, end cap 111 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 111 is not easily deformed under pressure and impact, giving battery cell 111 higher structural strength and improved safety performance. Functional components such as electrode terminals 130 can be provided on end cap 111. The material of end cap 111 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0086] Electrode assemblies are components within the battery cell 11 where electrochemical reactions occur. The housing 110 may contain one or more electrode assemblies. Figure 4 For schematic diagrams of electrode assemblies in some embodiments of this application, please refer to [link / reference]. Figure 4 The electrode assembly includes a positive electrode, a negative electrode, and a separator 123. During the charging and discharging process of the battery cell 11, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrode. The separator 123 is disposed between the positive and negative electrode to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0087] The electrode assembly includes an electrode body 122 and a first tab 121 and a second tab extending from the electrode body 122. The first tab 121 and the second tab can conduct current from the electrode assembly. The first tab 121 and the second tab have opposite polarities, with one of them being a positive tab and the other a negative tab.

[0088] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked. In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound together. For example, the positive electrode, the separator 123, and the negative electrode are wound into a cylindrical wound structure to obtain a cylindrical electrode assembly.

[0089] In some embodiments, the positive electrode sheet may include a positive current collector 1221 and a positive active material layer disposed on at least one surface of the positive current collector 1221. As an example, the positive current collector 1221 has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector 1221.

[0090] As an example, the positive current collector 1221 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloy, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0091] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM)523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0092] In some embodiments, the negative electrode sheet may include a negative electrode current collector 1222 and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector 1222. As an example, the negative electrode current collector 1222 has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector 1222.

[0093] As an example, the negative electrode current collector 1222 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloy, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0094] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 11. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cell 11 may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0095] In some embodiments, the positive current collector 1221 may be made of aluminum, and the negative current collector 1222 may be made of copper.

[0096] In some embodiments, such as Figure 4 As shown, the positive electrode current collector 1221 includes a positive electrode main body region 1221a and a positive electrode blank region 1221b. The positive electrode main body region 1221a is covered with a positive electrode active material layer, while the positive electrode blank region 1221b is not covered with a positive electrode active material layer.

[0097] In some embodiments, such as Figure 4 As shown, the negative electrode current collector 1222 includes a negative electrode main body region 1222a and a negative electrode blank region 1222b. The negative electrode main body region 1222a is covered with a negative electrode active material layer, while the negative electrode blank region 1222b is not covered with a positive electrode active material layer.

[0098] As an example, the electrode body 122 includes a positive electrode active material layer, a positive electrode body region 1221a, a negative electrode active material layer, a negative electrode body region 1222a, and a separator 123. At least a portion of the positive electrode blank region 1221b protrudes to the outside of the separator 123, and at least a portion of the negative electrode blank region 1222b protrudes to the outside of the separator 123. In some examples, such as Figure 4 As shown, the portion of the positive electrode blank area 1221b that protrudes to the outside of the separator 123 constitutes the positive electrode tab, and the portion of the negative electrode blank area 1222b that protrudes to the outside of the separator 123 constitutes the negative electrode tab.

[0099] In some embodiments, the separator 123 is a separator membrane. The separator membrane of this application can be any known porous membrane with good chemical and mechanical stability.

[0100] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different. The separator 123 can be a separate component located between the positive and negative electrode plates, or it can be attached to the surface of the positive or negative electrode plate. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0101] In some embodiments, the battery cell 11 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0102] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0103] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0104] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0105] Figure 5 This is a schematic diagram of the connection between a battery cell and a busbar component, omitting the pressure relief section and electrode terminals, according to some embodiments of this application. Figure 6 for Figure 5 The diagram shown is an exploded view of the battery cell and the busbar component. Figure 7 This is a cross-sectional schematic diagram of a battery cell according to some embodiments of this application. Figure 8 for Figure 7 A magnified view of a portion at point A. Please refer to [link / reference]. Figure 3 , Figures 5 to 8 The battery cell 11 in this embodiment further includes an electrode terminal 130 and a pressure relief portion 140. The housing 110 has a first end wall 1122, which is provided with an electrode lead-out hole 1123. The first end wall 1122 is electrically connected to a second tab (not shown). The electrode terminal 130 is disposed in the electrode lead-out hole 1123 and connected to the first tab 121. The electrode terminal 130 has an annular structure and an inner hole 134. The pressure relief portion 140 is connected to the electrode terminal 130 through an annular weak portion 150. The annular weak portion 150 is arranged circumferentially along the inner hole 134. The pressure relief portion 140 seals the inner hole 134. The annular weak portion 150 is configured to crack when the battery cell 11 is depressurized.

[0106] The outer casing 110 can be a cylindrical casing, a square casing, a prismatic casing, or other shapes. As an example, the material of the outer casing 110 can be conductive materials such as copper, iron, aluminum, stainless steel, or aluminum alloy. In some embodiments, the outer casing 110 can be a sealed structure or a non-sealed structure. As an example, when the outer casing 110 is a non-sealed structure, it serves to protect the electrode assembly 120, and a sealing bag is included between the outer casing 110 and the electrode assembly 120. The sealing bag is used to encapsulate the electrode assembly 120 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the outer casing 110 is a sealed structure, it is used to encapsulate the electrode assembly 120 and electrolyte components.

[0107] The first end wall 1122 can be either the end cap 111 or an end wall of the housing 112. Furthermore, the housing 110 also has a second end wall, with the first end wall 1122 and the second end wall arranged opposite to each other along the axial direction of the electrode assembly 120. Figure 6 In the figure, the first end wall 1122 is located above the second end wall. In the accompanying drawings of the embodiments of this application, the axial direction of the electrode assembly 120 can be referred to in the Z direction.

[0108] As an example, the housing 112 may have an opening at one end, specifically formed at the top of the housing 112. An end cap 111 is provided and covers the top of the housing 112. In this example, the end cap 111 is formed as a first end wall 1122, and the end wall of the housing 112 is formed as a second end wall. As an example, the housing 112 may have an opening at one end, specifically formed at the bottom of the housing 112. An end cap 111 is provided and covers the bottom of the housing 112. In this example, the end wall of the housing 112 is formed as a first end wall 1122, and the end cap 111 is formed as a second end wall. As an example, the housing 112 may have openings at both ends, and two end caps 111 are provided, each covering one of the two openings of the housing 112. In this example, the upper end cap 111 may be formed as a first end wall 1122, and the lower end cap 111 may be formed as a second end wall. The shape of the electrode lead-out hole 1123 is adapted to the shape of the electrode terminal 130. For example, the electrode lead-out hole 1123 can be square, round, oblong, etc.

[0109] As an example, if the second electrode tab is the positive electrode tab and the first electrode tab 121 is the negative electrode tab, then the first end wall 1122 is the positive electrode and the electrode terminal 130 is the negative electrode. Alternatively, if the second electrode tab is the negative electrode tab and the first electrode tab 121 is the positive electrode tab, then the first end wall 1122 is the negative electrode and the electrode terminal 130 is the positive electrode. The first electrode tab 121 is located at the end of the electrode body 122 facing the first end wall 1122. The first electrode tab 121 and the second electrode tab can be led out from the same end of the electrode body 122, so the second electrode tab is also located at the end of the electrode body 122 facing the first end wall 1122. In this example, the second electrode tab and the first end wall 1122 can be directly connected by welding or other methods, or they can be indirectly connected. In some alternative embodiments, the first tab 121 and the second tab can be led out from different ends of the electrode body 122. The second tab is then located at the end of the electrode body 122 opposite to the first end wall 1122. In this example, the second tab is directly or indirectly connected to the second end wall to achieve electrical connection with the first end wall 1122. In a specific example, the first tab 121 and the second tab can be led out from different ends of the electrode body 122. The battery cell 11 may also include a second current collector 1126, located between the electrode assembly 120 and the second end wall. The second tab is connected to the second end wall through the second current collector 1126. Thus, the current flow path from the second tab is: second tab - second current collector 1126 - second end wall - peripheral wall 1121 - first end wall 1122. Figure 6 As shown, the second current collector 1126 can be a disk-shaped structure.

[0110] Electrode terminal 130 is used for electrical connection with the first tab 121 of electrode assembly 120 for outputting or inputting electrical energy of battery cell 11. At least a portion of electrode terminal 130 passes through electrode lead-out hole 1123. Electrode terminal 130 has an annular structure and an inner peripheral surface that surrounds an inner hole 134. In some embodiments, such as Figure 7 and Figure 8As shown, the electrode terminal 130 may include a main body 131, a first flange 132, and a second flange 133. The main body 131 passes through the electrode lead-out hole 1123. Both ends of the main body 131 along the axial direction of the electrode assembly 120 are connected to the first flange 132 and the second flange 133, respectively. Both the first flange 132 and the second flange 133 extend towards the peripheral sidewall 1121 in a direction perpendicular to the axial direction of the electrode assembly 120. Both the first flange 132 and the second flange 133 are disposed opposite to the first end wall 1122. The first flange 132 is located on the side of the first end wall 1122 away from the electrode assembly 120, and the second flange 133 is located on the side of the first end wall 1122 facing the electrode assembly 120. That is, the first flange 132 is located outside the housing 110, and the second flange 133 is located inside the housing 110. Specifically, the second flange portion 133 is connected to the first electrode 121, so that the current flow path from the first electrode 121 is: first electrode 121 - second flange portion 133 - main body portion 131 - first flange portion 132.

[0111] The shape of the pressure relief section 140 is adapted to the shape of the inner hole 134. For example, the inner hole 134 can be square, circular, oblong, etc. The pressure relief section 140 is connected to the electrode terminal 130 via the annular weak portion 150. Simultaneously, through the connection between the annular weak portion 150 and the electrode terminal 130, the pressure relief section 140 seals the inner hole 134. "The annular weak portion 150 is configured to crack when the battery cell 11 is depressurized" means that when the internal pressure or temperature of the battery cell 11 reaches a threshold, at least a portion of the annular weak portion 150 ruptures, breaks, or is torn, causing the inner hole 134 to open, and the mounting cavity within the casing 110 communicates with the outside through the inner hole 134. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 11.

[0112] The pressure relief mechanism of the battery cell 11 in this embodiment is roughly as follows: Thermal runaway occurs in the battery cell 11, generating high-temperature, high-pressure substances inside. This causes the internal pressure or temperature of the battery cell 11 to reach a threshold. The connection between the electrode terminal 130 and the pressure relief section 140 cracks along the annular weak section 150. The high-temperature, high-pressure substances force open the pressure relief section 140, opening the inner hole 134 and connecting it to the outside of the outer casing. The high-temperature, high-pressure substances are discharged to the outside of the outer casing 110 through the inner hole 134, thereby releasing the internal temperature and pressure of the battery cell 11. The high-temperature, high-pressure substances mentioned herein include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature, high-pressure gases generated during the reaction, flames, etc.

[0113] In this embodiment, the battery cell 11 has an electrode terminal 130 with an annular structure and an inner hole 134, and a pressure relief part 140 is provided to be connected to the electrode terminal 130 through an annular weak part 150. The annular weak part 150 is arranged circumferentially along the inner hole 134. The annular weak part 150 is configured to crack when the battery cell 11 is depressurized to open the inner hole 134, thereby realizing pressure relief. Therefore, the orthographic projection of the electrode terminal 130 along the axial direction of the electrode assembly 120 on the first end wall 1122 in the battery cell 11 overlaps with the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 on the first end wall 1122. This allows a portion of the first end wall 1122 to be used to simultaneously arrange the electrode terminal 130 and the pressure relief portion 140, without the pressure relief portion 140 occupying additional space on the first end wall 1122. This improves the area utilization of the first end wall 1122 and alleviates the conflict caused by the electrode terminal 130 and the pressure relief portion 140 each occupying a portion of the area on the first end wall 1122, which prevents the simultaneous fulfillment of overcurrent and pressure relief requirements. The battery cell 11 in this embodiment can balance overcurrent and pressure relief capabilities.

[0114] Furthermore, in this embodiment, the battery cell 11 draws out current and relieves pressure at the same end. Thus, when the power system of the electrical device is composed using the battery cell 11 of this embodiment, the space occupied by the bus component 30 (see below) used to connect with the electrode terminal 130 and the first end wall 1122 to draw out current can be reused as a pressure relief space. There is no need to reserve additional pressure relief space on the side away from the first end wall 1122. This can have a positive effect on improving the compactness of the electrical device structure.

[0115] When the battery device of an electrical device is composed of the battery cell 11 of this embodiment, other functional structures can be arranged on the side away from the first end wall 1122, thereby increasing the possibilities for the structural design of the electrical device. For example, when the battery cell 11 of this embodiment is used to compose the battery device of an electric vehicle, the battery device may include a heat exchange assembly. The heat exchange assembly and the battery cell 11 are arranged sequentially along the axial direction of the electrode assembly 120, and the heat exchange assembly is located on the side of the second end wall away from the first end wall 1122 and exchanges heat with the battery cell 11.

[0116] It is understandable that the specific connection method between the annular weak part 150 and the electrode terminal 130 is varied.

[0117] According to some embodiments of this application, such as Figure 7 and Figure 8As shown, the annular weak portion 150 is sealed to the wall of the inner hole 134, and the annular weak portion 150 can be arranged around the outer periphery of the pressure relief portion 140. The housing 110 may also include a second end wall, which is opposite to the first end wall 1122 along the axial direction of the electrode assembly 120; the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 onto the second end wall falls within the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 onto the second end wall.

[0118] In this embodiment, the annular weak portion 150 and the pressure relief portion 140 are located within the inner hole 134. The pressure relief portion 140 is sealed to the hole wall of the inner hole 134 through the annular weak portion 150, thereby sealing the inner hole 134. Taking an example where both the inner hole 134 and the pressure relief portion 140 are circular, i.e., the outer diameter of the pressure relief portion 140 is smaller than the diameter of the inner hole 134. The sealed connection can be achieved through integral connection, welding connection, or other methods. As an example, the annular weak portion 150 and the hole wall of the inner hole 134 can be integrally formed, and the annular weak portion 150 and the pressure relief portion 140 can also be integrally formed. In this example, the electrode terminal 130 and the pressure relief portion 140 are integrally formed. A groove, a notch, or other structure can be formed at the connection position between the electrode terminal 130 and the pressure relief portion 140 to create the annular weak portion 150. It should be noted that the electrode terminal 130 can be made of conductive metal materials, conductive polymer materials, etc., and the pressure relief portion 140 can be made of insulating materials such as plastic.

[0119] Using this technical solution, if the internal pressure or temperature of the battery cell 11 in this embodiment reaches a threshold, and the annular weak part 150 partially cracks, the inner hole 134 will open in a local position. Since the annular weak part 150 and the pressure relief part 140 are located inside the inner hole 134, the high-temperature and high-pressure material can be discharged to the outside of the outer casing 110 through the inner hole 134 without changing the flow direction. This can have a positive effect on improving the smoothness of pressure relief.

[0120] Figure 9 This is a cross-sectional schematic diagram of a battery cell 11 according to other embodiments of this application. Figure 10 for Figure 9 A partially enlarged schematic diagram at point B. See also some embodiments of this application. Figure 9 and Figure 10 The pressure relief part 140 is located on the side of the electrode terminal 130 away from the electrode assembly 120 along the axial direction of the electrode assembly 120, and the annular weak part 150 can be connected to the periphery of the inner hole 134.

[0121] exist Figure 10 In this embodiment, the pressure relief portion 140 is located above the electrode terminal 130, and the annular weak portion 150 is connected to the surface of the electrode terminal 130 facing away from the electrode assembly 120. In this embodiment, the annular weak portion 150 surrounds the outer periphery of the inner hole 134.

[0122] In this technical solution, the annular weak portion 150 and the pressure relief portion 140 are located outside the inner hole 134. Thus, when the pressure relief portion 140 is welded to the electrode terminal 130 using laser welding, and the welded joint is used as the annular weak portion 150, the laser is less likely to directly strike the electrode assembly 120 during the welding process because the annular weak portion 150 and the pressure relief portion 140 are located outside the inner hole 134, reducing the possibility of laser damage to the electrode assembly 120.

[0123] According to some embodiments of this application, such as Figure 10 As shown, the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 onto the second end wall can fall within the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 onto the second end wall. Taking an example where both the inner hole 134 and the pressure relief portion 140 are circular, i.e., the outer diameter of the pressure relief portion 140 is larger than the diameter of the inner hole 134, in this example, the annular weak portion 150 can be connected to the surface of the pressure relief portion 140 facing the first end wall 1122 and / or the outer peripheral surface of the pressure relief portion 140.

[0124] According to some embodiments of this application, the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 onto the second end wall may coincide with the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 onto the second end wall.

[0125] Taking a case where both the inner hole 134 and the pressure relief portion 140 are circular, that is, the outer diameter of the pressure relief portion 140 is equal to the diameter of the inner hole 134, in other words, the outer peripheral surface of the pressure relief portion 140 is aligned with the hole wall of the inner hole 134 along the axial direction of the electrode assembly 120. In this example, the annular weak portion 150 can be connected to the outer peripheral surface of the pressure relief portion 140.

[0126] Compared with the technical solution where the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 on the second end wall falls within the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 on the second end wall, in the battery cell 11 of this embodiment, since the orthographic projection of the pressure relief portion 140 along the axial direction of the electrode assembly 120 on the second end wall coincides with the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 on the second end wall, the size of the pressure relief portion 140 is smaller, and the pressure relief portion 140 is easier to be opened, so that high-temperature and high-pressure substances can be discharged more smoothly.

[0127] According to some embodiments of this application, the pressure relief portion 140 is welded to the electrode terminal 130 to form a welded portion, which is then formed as an annular weak portion 150. Ultrasonic welding, laser welding, friction welding, or other welding processes can be used to weld the pressure relief portion 140 to the electrode terminal 130. Furthermore, a continuous weld mark (i.e., a welded portion) is formed between the pressure relief portion 140 and the electrode terminal 130 using a continuous welding method. The welded portion can be used as the annular weak portion 150 by controlling the welding process.

[0128] Taking laser welding process as an example, such as Figure 7 and Figure 8 As shown, in the technical solution where the annular weak portion 150 is sealed to the wall of the inner hole 134, and the annular weak portion 150 surrounds the outer periphery of the pressure relief portion 140, the laser projection direction is parallel to the axial direction of the electrode assembly 120 during welding. In this embodiment, the welding process can be controlled so that the dimension of the welded portion along the axial direction of the electrode assembly 120 is smaller than the dimension of the pressure relief portion 140 along the axial direction of the electrode assembly 120, thus making the welded portion weaker than the pressure relief portion 140.

[0129] Taking laser welding process as an example, such as Figure 9 and Figure 10 As shown, in the technical solution where the pressure relief part 140 is located on the side of the electrode terminal 130 away from the electrode assembly along the axial direction of the electrode assembly, and the annular weak part 150 is connected to the periphery of the inner hole 134, the projection direction of the laser can be perpendicular to the axial direction of the electrode assembly 120 during the welding process.

[0130] By employing this technical solution, the pressure relief section 140 is welded to the electrode terminal 130, while simultaneously forming an annular weak section 150. This eliminates the need for additional processing steps to form the annular weak section 150, simplifying the manufacturing process. Furthermore, the welded portion in this method forms a continuous physical barrier, ensuring a reliable seal for the inner hole 134.

[0131] According to some embodiments of this application, the battery cell 11 may further include a first current collector 1124 and a second current collector 1126. Along the axial direction of the electrode assembly, the first current collector 1124 is located between the electrode assembly 120 and the electrode terminal 130. The first tab 121 is connected to the electrode terminal 130 through the first current collector 1124. The first current collector 1124 may be provided with a through hole 1125, which is opposite to and communicates with the inner hole 134.

[0132] Both the first current collector 1124 and the second current collector 1126 are components capable of conducting current. The second current collector 1126 is electrically connected to the first end wall 1122. The polarities of the first current collector 1124 and the second current collector 1126 are opposite. When the first tab 121 and the second tab are led out from the same end of the electrode body 122, the second current collector 1126 is located on the side of the electrode assembly 120 facing the first end wall 1122, and the second current collector 1126 can be directly welded to the first end wall 1122; when the first tab 121 and the second tab are led out from different ends of the electrode body 122, the second current collector 1126 is located on the side of the electrode assembly 120 away from the first end wall 1122, and the second current collector 1126 can be located between the electrode assembly 120 and the second end wall and connected to the second end wall.

[0133] exist Figure 8 In this configuration, electrode terminal 130 is stacked above first current collector 1124, and first current collector 1124 is stacked above first tab 121. The first current collector 1124 and the second flange portion 133 of electrode terminal 130 are electrically connected by welding.

[0134] The through hole 1125 extends through the first current collector 1124 along the axial direction of the electrode assembly 120. "The through hole 1125 is opposite to the inner hole 134" means that the orthographic projection of the through hole 1125 along the axial direction of the electrode assembly 120 onto the second end wall at least partially overlaps with the orthographic projection of the inner hole 134 along the axial direction of the electrode assembly 120 onto the second end wall. The shape of the through hole 1125 is not limited; for example, it can be circular, rectangular, elongated, waist-shaped, or cross-shaped, etc.

[0135] By providing a through hole 1125 in the first current collector 1124 located between the electrode assembly 120 and the electrode terminal 130, the high-temperature and high-pressure material inside the battery cell 11 can flow to the pressure relief part 140 through the through hole 1125 and the inner hole 134, so that the first current collector 1124 will not block the high-temperature and high-pressure material, thus ensuring that pressure relief can be achieved.

[0136] According to some embodiments of this application, the inner hole 134 can be a liquid injection hole for injecting electrolyte into the housing 110.

[0137] In this embodiment, before the pressure relief section 140 is connected to the electrode terminal 130 through the annular weak portion 150, the inner hole 134 is not covered by the pressure relief section 140, and electrolyte can be injected into the housing 110 through the inner hole 134. An exemplary assembly process of the battery cell 11 can be as follows: inserting the electrode assembly 120 into the housing 112 - connecting the second flange portion 133 to the electrode assembly 120 - covering the opening of the housing 112 with the end cap 111 and connecting the housing 112 to the end cap 111 - installing the main body portion 131 to the electrode lead-out hole 1123 - connecting the first flange portion 132 to the main body portion 131, such that the second flange portion 133, the main body portion 131 and the first flange portion 132 form the electrode terminal 130 - injecting electrolyte into the housing 110 through the inner hole 134 - connecting the pressure relief section 140 to the electrode terminal 130 through the annular weak portion 150.

[0138] Using this technical solution, the inner hole 134 can be reused as an injection hole. In this way, there is no need to open an additional injection hole on the first end wall 1122. The area of ​​the first end wall 1122 for connecting with the busbar component 30 can be larger, and the flow area between the first end wall 1122 and the busbar component 30 can be larger, which is beneficial to improving the flow capacity of the battery cell 11.

[0139] According to some embodiments of this application, the inner hole 134 can also be a formation vent hole, which is used to vent gas during the formation of the battery cell 11. In this embodiment, after the electrolyte is injected into the battery cell 11, it can be left to stand for a period of time before the formation process is performed. The gas generated during the formation process can be discharged through the inner hole 134. After the formation is completed, the pressure relief part 140 is connected to the electrode terminal 130 through the annular weak part 150 to seal the inner hole 134.

[0140] Using this technical solution, the inner hole 134 can be reused as a formation vent. In this way, there is no need to open an additional formation vent on the first end wall 1122. The area of ​​the first end wall 1122 for connecting with the busbar component 30 can be larger, and the flow area between the first end wall 1122 and the busbar component 30 can be larger, which is beneficial to improving the flow capacity of the battery cell 11.

[0141] Figure 11 This is a top view of a battery cell 11 according to some embodiments of this application. According to some embodiments of this application, such as... Figure 5 , Figure 6 and Figure 11 As shown, the outer casing 110 can be cylindrical, with a cross section perpendicular to the axial direction of the electrode assembly 120 as the cross section. The cross sections of the pressure relief part 140, the electrode terminal 130, and the first end wall 1122 are all circular and coaxially arranged.

[0142] In this embodiment, the battery cell 11 is a cylindrical battery cell 11. From a top viewpoint, as... Figure 11 As shown, the pressure relief part 140, the first flange part 132 of the electrode terminal 130 and the first end wall 1122 are circular and coaxially arranged, and the pressure relief part 140, the first flange part 132 and the first end wall 1122 are arranged sequentially from the center of the battery cell 11 to the outer periphery.

[0143] With this technical solution, the annular weak part 150 is circular. When the battery cell 11 is depressurized, the force on each position of the annular weak part 150 is more uniform. The connection position between the electrode terminal 130 and the depressurization part 140 is more likely to crack along the circumference of the annular weak part 150, making it easier for the depressurization part 140 to separate from the electrode terminal 130, so that the entire inner hole 134 can be opened, which is conducive to achieving rapid depressurization.

[0144] In some embodiments, please continue reading Figure 8 and Figure 10The battery cell 11 may further include a first insulating member 160 and a second insulating member 170. The first insulating member 160 is located outside the housing 110 and is situated between the first flange portion 132 and the first end wall 1122 of the electrode terminal 130, thereby insulating the first flange portion 132 and the first end wall 1122. The second insulating member 170 is located inside the housing 110 and, along the axial direction of the electrode assembly, is situated between the first end wall 1122 and the second flange portion 133 of the electrode terminal 130, thereby insulating the second flange portion 133 from the first end wall 1122.

[0145] In some embodiments, the battery cell 11 may further include a sealing ring 180, which is located at the electrode lead-out hole 1123 and surrounds the main body portion 131 of the electrode terminal 130 to seal the gap between the main body portion 131 and the electrode lead-out hole 1123. The sealing ring 180 may be made of insulating materials such as rubber or plastic to insulate the main body portion 131 from the first end wall 1122.

[0146] An embodiment of the second aspect of this application provides a battery device, such as... Figure 2 As shown, it includes the battery cell 11 in the above embodiments.

[0147] It is understood that the battery device provided in this application, by using any of the aforementioned battery cells 11, has all the beneficial effects of the aforementioned battery cells 11, which will not be elaborated here.

[0148] Figure 12 This is a top view schematic diagram of the bus component 30 according to some embodiments of this application. Please refer to [link / reference] for some embodiments of this application. Figure 5 , Figure 6 and Figure 12 The battery device may further include a busbar component 30, which includes two connected busbars 31, each corresponding to one of the two battery cells 11. At least one busbar 31 is electrically connected to the electrode terminal 130 of the corresponding battery cell 11, and the orthographic projection of at least one busbar 31 along the axial direction of the electrode assembly 120 onto the first end wall 1122 does not overlap with the orthographic projection of the inner hole 134, the pressure relief portion 140, and the annular weak portion 150 of the corresponding battery cell 11 along the axial direction of the electrode assembly 120 onto the first end wall 1122; and / or, at least one busbar 31 is electrically connected to the first end wall 1122 of the corresponding battery cell 11, and the orthographic projection of at least one busbar 31 along the axial direction of the electrode assembly 120 onto the first end wall 1122 does not overlap with the orthographic projection of the electrode terminal 130, the pressure relief portion 140, and the annular weak portion 150 of the corresponding battery cell 11 along the axial direction of the electrode assembly 120 onto the first end wall 1122.

[0149] A busbar component 30 refers to a component capable of conducting current. The two busbar elements 31 of the busbar component 30 can be integrally formed or connected by welding, snap-fitting, screwing, or other methods. In some embodiments, such as... Figure 12 As shown, the busbar component 30 may also include a conductive connector 32, and the two busbar components 31 are connected by the conductive connector 32. The conductive connector 32 may be constructed as a columnar structure, a sheet structure, etc.

[0150] As an example, one of the busbars 31 of the busbar component 30 can be electrically connected to the electrode terminal 130 of one battery cell 11, and the other busbar 31 can be electrically connected to the first end wall 1122 of another battery cell 11, thus realizing the series connection of two battery cells 11.

[0151] As an example, there are two current collectors 30, namely a positive current collector and a negative current collector. One current collector 31 of the positive current collector can be electrically connected to the electrode terminal 130 of one battery cell 11, and the other current collector 31 can be electrically connected to the electrode terminal 130 of another battery cell 11. One current collector 31 of the negative current collector can be electrically connected to the first end wall 1122 of one battery cell 11, and the other current collector 31 can be electrically connected to the first end wall 1122 of another battery cell 11, thus realizing the parallel connection of the two battery cells 11.

[0152] In other words, the busbar 31 can be connected to the corresponding electrode terminal 130 or the first end wall 1122 to achieve series, parallel, or mixed connections. The busbar 31 and the corresponding electrode terminal 130 or the first end wall 1122 can be connected by welding. When the busbar 31 is connected to the corresponding electrode terminal 130, the orthographic projection of the busbar 31 along the axial direction of the electrode assembly 120 onto the first end wall 1122 does not overlap with the orthographic projections of the inner hole 134, the pressure relief portion 140, and the annular weak portion 150 of the corresponding electrode terminal 130 along the axial direction of the electrode assembly 120 onto the first end wall 1122. In other words, the busbar 31 will not obstruct the inner hole 134, the pressure relief portion 140, and the annular weak portion 150.

[0153] When the busbar 31 is connected to the corresponding first end wall 1122, the orthographic projection of the busbar 31 along the axial direction of the electrode assembly 120 onto the first end wall 1122 does not overlap with the orthographic projection of the corresponding electrode terminal 130 (i.e., the electrode terminal 130 provided on the corresponding first end wall 1122), the pressure relief part 140, and the annular weak part 150 along the axial direction of the electrode assembly 120 onto the first end wall 1122. In other words, the busbar 31 is located on the outer periphery of the electrode terminal 130, and the busbar 31 will not block the corresponding electrode terminal 130 and its inner hole 134, pressure relief part 140, and annular weak part 150.

[0154] Using this technical solution, multiple battery cells 11 are connected in series, parallel, or mixed via a busbar component 30. Furthermore, the busbar component 31 connected to the electrode terminal 130 does not obstruct the inner hole 134, the pressure relief section 140, or the annular weak section 150. The busbar component 31 connected to the first end wall 1122 is located on the outer periphery of the electrode terminal 130, thus avoiding both short circuits caused by connection to the electrode terminal 130 and obstruction of the inner hole 134, the pressure relief section 140, and the annular weak section 150. Therefore, the busbar component 30 as a whole does not obstruct the inner hole 134, the pressure relief section 140, or the annular weak section 150, ensuring that the busbar component 30 does not impede the discharge of high-temperature, high-pressure substances, allowing the battery cell 11 to release pressure smoothly.

[0155] To ensure that the busbar 31 does not obstruct the inner hole 134, the pressure relief portion 140, and the annular weak portion 150, the shape of the busbar 31 can be varied. For example, the orthographic projection of the busbar 31 along the axial direction of the electrode assembly 120 onto the first end wall 1122 can be a non-closed shape. In a specific example, the housing 110 is cylindrical, with a cross-section perpendicular to the axial direction of the electrode assembly 120. The cross-sections of the pressure relief portion 140, the electrode terminal 130, and the first end wall 1122 are all circular and coaxially arranged. In this example, the busbar 31 can be semi-circular, or it can be a superior or inferior arc shape.

[0156] According to some embodiments of this application, please refer to Figure 5 , Figure 6 and Figure 12 Both busbars 31 can be configured in a ring shape, and each busbar 31 is adapted to the shape of the corresponding electrode terminal 130 or the corresponding first end wall 1122.

[0157] In this embodiment, the busbar 31 has a closed shape in the orthographic projection of the first end wall 1122 along the axial direction of the electrode assembly 120. It can be understood that the busbar 31, as an annular structure, has a central hole 311, and the axis of the central hole 311 can be collinear with the axis of the inner hole 134.

[0158] For the manifold 31 connected to the first end wall 1122, the wall of the central hole 311 of the manifold 31 surrounds the outer periphery of the first flange portion 132 of the electrode terminal 130 provided on the corresponding first end wall 1122. That is, both the electrode terminal 130 and the pressure relief portion 140 are located inside the central hole 311 of the manifold 31. Taking the example that both the first flange portion 132 and the central hole 311 are circular, the diameter of the central hole 311 is larger than the outer diameter of the first flange portion 132.

[0159] For the manifold 31 connected to the electrode terminal 130, the wall of the central hole 311 of the manifold 31 surrounds the wall of the inner hole 134, the pressure relief portion 140, and the outer periphery of the annular weak portion 150. When the annular weak portion 150 cracks, the inner hole 134 communicates with the central hole 311 of the manifold 31 to form an exhaust channel. Taking the example that both the inner hole 134 and the central hole 311 are circular, the diameter of the central hole 311 is larger than the diameter of the inner hole 134.

[0160] For example, when the housing 110 is cuboid and the cross-section of the electrode terminal 130 is rectangular, the busbar 31 can be annular to adapt to the shape of the corresponding electrode terminal 130 or the corresponding first end wall 1122. For example, when the housing 110 is cylindrical with a cross-section perpendicular to the axial direction of the electrode assembly 120, and the pressure relief portion 140, the cross-section of the electrode terminal 130, and the first end wall 1122 are all circular and coaxially arranged, the busbar 31 can be annular to adapt to the shape of the corresponding electrode terminal 130 or the corresponding first end wall 1122.

[0161] It is easy to understand that when two battery cells 11 are connected in series via a busbar 30, the cross-sectional dimensions of the central holes 311 of the two busbars 31 of the busbar 30 are different, with a cross-section perpendicular to the axial direction of the electrode assembly 120 as the cross-section. In a specific example, the housing 110 is cylindrical, with a cross-section perpendicular to the axial direction of the electrode assembly 120 as the cross-section. The pressure relief section 140, the cross-section of the electrode terminal 130, and the first end wall 1122 are all circular and coaxially arranged, such as... Figure 5 , Figure 6 and Figure 12 As shown, the diameters of the central holes 311 of the two manifolds 31 of the manifold 30 are not equal.

[0162] When two battery cells 11 are connected in parallel through a busbar 30, the cross-sectional dimensions of the central holes 311 of the two busbars 31 of the busbar 30 can be the same.

[0163] In this technical solution, the busbar 31 has a central hole 311. On the one hand, the annular weak portion 150 and the pressure relief portion 140 can be exposed to the outside of the battery cell 11 through the central hole 311, so that the busbar 30 will not obstruct the discharge of high-temperature and high-pressure substances, allowing the battery cell 11 to release pressure smoothly. On the other hand, compared with the technical solution where the orthographic projection shape of the busbar 31 along the axial direction of the electrode assembly 120 on the first end wall 1122 is not closed, in this embodiment both busbars 31 are annular, and the area of ​​the busbar 31 is larger. Therefore, the flow area between the battery cell 11 and the busbar 30 can be larger, which can improve the flow capacity of the battery cell 11.

[0164] An embodiment of the third aspect of this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0165] The electrical equipment includes vehicles (such as cars, electric vehicles, ships, spacecraft, etc.), display devices (such as mobile phones, tablets, laptops, etc.), electric toys, power tools, etc. It is understood that the electrical equipment provided in this application, by employing any of the aforementioned battery devices, possesses all the beneficial effects of those battery devices, which will not be elaborated further here.

[0166] An embodiment of the fourth aspect of this application provides an energy storage device, which includes the battery device in the above embodiments, the battery device being used for energy storage.

[0167] Energy storage devices can include, but are not limited to, centralized energy storage devices (such as containerized energy storage devices), distributed energy storage devices, mobile energy storage devices, wearable energy storage devices, and so on.

[0168] It is understood that the energy storage device provided in this application, by using any of the aforementioned battery devices, has all the beneficial effects of the aforementioned battery devices, which will not be elaborated here.

[0169] The above description is merely an overview of the technical solution of this application. To enable a clearer understanding of the technical means of this application and to facilitate its implementation according to the description, and to make the above and other objects, features, and advantages of this application more apparent, specific embodiments of this application are described below.

[0170] A specific embodiment of this application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the scope of this application.

[0171] like Figure 3 , Figures 5 to 8As shown, the cylindrical battery cell 11 includes a housing 110, an electrode assembly 120, and electrode terminals 130. The housing 110 includes a shell 112 and an end cap 111. The bottom end of the shell 112 is open, and the end cap 111 covers the bottom end of the shell 112. The end wall of the shell 112 opposite to the end cap 111 is a first end wall 1122, and the first end wall 1122 is provided with an electrode lead-out hole 1123. The electrode assembly 120 is housed within the housing 110. The electrode assembly 120 includes an electrode body 122, a first tab 121, and a second tab. The first tab 121 extends from the top end of the electrode body 122, and the second tab extends from the bottom end of the electrode body 122. A second current collector 1126 is stacked between the second tab and the end cap 111. The second tab is electrically connected to the end cap 111 through the second current collector 1126, thereby achieving electrical connection with the first end wall 1122.

[0172] Electrode terminal 130 is located at electrode lead-out hole 1123. Electrode terminal 130 has an annular structure and an inner hole 134. A first current collector 1124 is stacked between electrode terminal 130 and first tab 121. The first tab 121 is electrically connected to electrode terminal 130 through the first current collector 1124. The first current collector 1124 has a through hole 1125, which is directly opposite to and communicates with the inner hole 134. Pressure relief part 140 is circular. Pressure relief part 140 is welded to the wall of the inner hole 134 to form a welded part. The welded part is continuously arranged along the circumference of the inner hole 134 and forms an annular weak part 150. The annular weak part 150 surrounds the outer periphery of pressure relief part 140. When the internal pressure or temperature of the battery cell 11 reaches a threshold, the annular weak part 150 cracks.

[0173] Cylindrical battery cell 11 is connected in series with another cylindrical battery cell 11 via a busbar 30. Specifically, the busbar 30 includes two annular busbars 31, the inner circumferential surface of which surrounds a central hole 311. One busbar 31 is stacked on the electrode terminal 130 of one cylindrical battery cell 11 and the two are electrically connected, and the central hole 311 of the one busbar 31 surrounds the outer periphery of the annular weak portion 150 of the one cylindrical battery cell 11. The other busbar 31 is stacked on the first end wall 1122 of another cylindrical battery cell 11 and the two are electrically connected, and the central hole 311 of the other busbar 31 surrounds the outer periphery of the electrode terminal 130 of the other cylindrical battery cell 11. When the internal pressure or temperature of the battery cell 11 reaches the threshold, the annular weak part 150 cracks, and the high-temperature and high-pressure material bursts through the through hole and opens the pressure relief part 140. The inner hole 134 opens, and the high-temperature and high-pressure material is discharged to the outside of the outer casing 110 through the inner hole 134 and the central hole 311 of one of the busbars 31.

[0174] 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 in that, include: The outer casing has a first end wall, and the first end wall is provided with an electrode lead-out hole; An electrode assembly is housed within the housing, the electrode assembly having a first tab and a second tab of opposite polarity, the second tab being electrically connected to the first end wall; An electrode terminal is provided in the electrode lead-out hole and connected to the first electrode tab; the electrode terminal has an annular structure and an inner hole; The pressure relief section is connected to the electrode terminal via an annular weak portion, which is arranged circumferentially along the inner hole. The pressure relief section seals the inner hole, and the annular weak portion is configured to crack when the battery cell is depressurized.

2. The battery cell according to claim 1, characterized in that, The annular weak portion is sealed to the wall of the inner hole, and the annular weak portion is arranged around the outer periphery of the pressure relief portion; The housing further includes a second end wall, which is opposite to the first end wall along the axial direction of the electrode assembly; the orthographic projection of the pressure relief portion along the axial direction of the electrode assembly onto the second end wall falls within the orthographic projection of the inner hole along the axial direction of the electrode assembly onto the second end wall.

3. The battery cell according to claim 1, characterized in that, The pressure relief section is located on the side of the electrode terminal opposite to the electrode assembly along the axial direction of the electrode assembly, and the annular weak section is connected to the periphery of the inner hole.

4. The battery cell according to claim 3, characterized in that, The housing further includes a second end wall, which is opposite to the first end wall along the axial direction of the electrode assembly; the orthographic projection of the pressure relief portion along the axial direction of the electrode assembly onto the second end wall coincides with the orthographic projection of the inner hole along the axial direction of the electrode assembly onto the second end wall.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The pressure relief section is welded to the electrode terminal to form a fusion joint, and the fusion joint forms the annular weak section.

6. The battery cell according to any one of claims 1 to 4, characterized in that, The battery cell further includes a first current collector located between the electrode assembly and the electrode terminal along the axial direction of the electrode assembly. The first tab is connected to the electrode terminal through the first current collector. The first current collector has a through hole that is opposite to and communicates with the inner hole.

7. The battery cell according to any one of claims 1 to 4, characterized in that, The inner hole is a liquid injection hole, which is used to inject electrolyte into the interior of the outer casing, and / or the inner hole is a formation vent hole, which is used to vent air during the formation of the battery cell.

8. The battery cell according to any one of claims 1 to 4, characterized in that, The outer shell is cylindrical, with a cross section perpendicular to the axial direction of the electrode assembly. The pressure relief section, the cross section of the electrode terminal, and the first end wall are all circular and coaxially arranged.

9. A battery device, characterized in that, It includes multiple battery cells as described in any one of claims 1 to 8.

10. The battery device according to claim 9, characterized in that, The battery device further includes a current-combining component, which includes two connected current-combining elements, each corresponding to one of the two battery cells. At least one of the busbars is electrically connected to the electrode terminal of the corresponding battery cell, and the orthographic projection of at least one of the busbars along the axial direction of the electrode assembly onto the first end wall does not overlap with the orthographic projection of the inner hole, the pressure relief portion, and the annular weak portion of the corresponding battery cell along the axial direction of the electrode assembly onto the first end wall; and / or, at least one of the busbars is electrically connected to the first end wall of the corresponding battery cell, and the orthographic projection of at least one of the busbars along the axial direction of the electrode assembly onto the first end wall does not overlap with the orthographic projection of the electrode terminal, the pressure relief portion, and the annular weak portion of the corresponding battery cell along the axial direction of the electrode assembly onto the first end wall.

11. The battery device according to claim 10, characterized in that, Both of the busbars are annular, and each busbar is adapted to the shape of the corresponding electrode terminal or the corresponding first end wall.

12. An electrical appliance, characterized in that, The electrical equipment includes a battery device as described in any one of claims 9 to 11, the battery device being used to provide electrical energy.

13. An energy storage device, characterized in that, The energy storage device includes a battery device as described in any one of claims 9 to 11, the battery device being used to store electrical energy.

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