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 first current collector. A first wall of the shell is provided with an electrode lead-out hole. The electrode terminal comprises a flange part and a main body part arranged in the electrode lead-out hole. The flange part is connected with the main body part at one end along the axial direction of the electrode assembly and is opposite to the first wall. The flange part is located in the shell. The main body part and the connection position of the flange part and the main body part along the axial direction of the electrode assembly fall in the electrode lead-out hole in the orthographic projection of the first wall. The main body part is disconnected with the flange part when the battery monomer is pressure released. The first current collector is stacked between the electrode assembly and the electrode terminal. The first current collector is provided with a through hole opposite to the electrode terminal. In the scheme, the electrode lead-out hole can be opened for pressure release. The electrode terminal and the electrode lead-out hole share part of the area of the first wall, and the problem that the pressure release 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 first current collector. The housing has a first 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 wall. The electrode terminal includes a body portion and a flange portion. The body portion is disposed at the electrode lead-out hole, and the flange portion is connected to one end of the body portion along a first direction and faces the first wall. The flange portion is located on the side of the first wall facing the electrode assembly. The orthographic projection of the body portion and the flange portion onto the first wall along the first direction falls within the electrode lead-out hole. The electrode terminal is configured such that the body portion can be disconnected from the flange portion when the battery cell is depressurized. The first direction is the axial direction of the electrode assembly. Along the first direction, the first current collector is located between the electrode assembly and the electrode terminal. The first tab is electrically connected to the electrode terminal through the first current collector. The first current collector has a through hole facing the electrode terminal.

[0006] In the technical solution of this application embodiment, the electrode terminal is configured to include a main body and a flange, and the main body can be disconnected from the flange when the battery cell is depressurized. Furthermore, the projection of the main body and the flange onto the first wall along a first direction falls within the electrode lead-out hole. This allows the main body, after separating from the flange, to detach from the electrode lead-out hole and exit the casing under the impact of high-temperature and high-pressure substances. The electrode lead-out hole is no longer blocked by the electrode terminal and opens, thus achieving pressure relief. In this embodiment, the electrode lead-out hole used for mounting the electrode terminal is used as a pressure relief port when open. This allows the electrode terminal and the pressure relief port to share a portion of the area of ​​the first wall, alleviating the conflict caused by the electrode terminal and the pressure relief port each occupying a portion of the area, preventing the simultaneous fulfillment of overcurrent and pressure relief requirements. The battery cell in this embodiment can balance overcurrent and pressure relief capabilities.

[0007] By providing a through hole in the first current collector located between the electrode assembly and the electrode terminal, the high-temperature and high-pressure material inside the battery cell can flow to the electrode terminal through the through hole, so that the first current collector will not block the high-temperature and high-pressure material, thus ensuring that pressure relief can be achieved.

[0008] In some embodiments, the flange portion includes a flange body and a weak portion disposed along the inner circumferential side of the flange body. The weak portion is projected onto the electrode lead-out hole along a first direction on the first wall. The strength of the weak portion is lower than the strength of the flange body. The weak portion is configured to crack when the battery cell is depressurized.

[0009] Using this technical solution, when the internal pressure or temperature of the battery cell reaches a threshold, the electrode terminal cracks along the weak part. Since the orthogonal projection of the weak part along the first direction onto the first wall falls into the electrode lead-out hole, the main body can be smoothly removed from the electrode lead-out hole, thus ensuring that pressure relief can be achieved smoothly.

[0010] In some embodiments, the dimension of the weak portion along the first direction is smaller than the dimension of the flange body along the first direction. Using this technical solution, assuming consistent materials, the thickness of the weak portion is less than the thickness of the flange body, and the weak portion is the weakest point of the flange.

[0011] In some embodiments, the melting point of the material of the flange portion is lower than that of the material of the body portion.

[0012] In some embodiments, the melting point of the flange material is less than or equal to 300°C. Using this technique, the high-temperature, high-pressure material can rapidly melt the flange, allowing the electrode terminals to respond quickly and release pressure.

[0013] In some embodiments, the melting point of the flange material is greater than or equal to 60°C and less than or equal to 180°C. This embodiment enables the electrode terminals to respond promptly and accurately to relieve pressure in the event of thermal runaway of a battery cell.

[0014] An embodiment of the second aspect of this application provides a battery device that includes the battery cell described in the above embodiments.

[0015] In some embodiments, the battery device further includes a first busbar stacked on one end of the main body away from the electrode assembly along a first direction and connected to the main body. The first busbar has a weak region configured to break when the battery cell is depressurized, and the orthogonal projection of the weak region along the first direction onto the outside of the main body is located.

[0016] When this technical solution is adopted, when the main body of the electrode terminal comes out from the electrode lead hole and rushes out of the outer casing during thermal runaway of a battery cell, the weak area of ​​the first busbar is damaged, which breaks the circuit between the battery cell and other battery cells. This helps to suppress the chain reaction caused by the further development of thermal runaway.

[0017] In some embodiments, the flange portion includes a flange body and a weak portion disposed along the inner circumferential side of the flange body. The orthographic projection of the weak portion along a first direction onto the first wall falls within the electrode lead-out hole. The strength of the weak portion is lower than the strength of the flange body. The weak portion is configured to crack when the battery cell is depressurized. The orthographic projection of the weak region along the first direction onto the first wall is further away from the main body portion than the orthographic projection of the weak portion along the first direction onto the first wall.

[0018] With this technical solution, the part of the first busbar that is connected to other battery cells after it breaks during depressurization will not cover the main body of the battery cell, so as to further ensure that the main body can be pushed out smoothly, thereby ensuring that depressurization is successfully achieved.

[0019] In some embodiments, the weak area is a hollow portion located in the first busbar.

[0020] 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.

[0021] 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.

[0022] 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

[0023] 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.

[0024] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0025] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0026] Figure 3 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0027] Figure 4 This is a schematic diagram of the structure of the electrode assembly in some embodiments of this application;

[0028] Figure 5 for Figure 3 The diagram shows the exploded structure of a single battery cell.

[0029] Figure 6 for Figure 3 A top view of the battery cell shown;

[0030] Figure 7 For along Figure 6 A partial cross-sectional view of line AA in the middle section;

[0031] Figure 8 for Figure 7 A magnified view of a portion of point B in the middle;

[0032] Figure 9 This is a cross-sectional schematic diagram of the electrode terminals of some embodiments of this application;

[0033] Figure 10 This is a partial cross-sectional schematic diagram of a battery cell according to other embodiments of this application;

[0034] Figure 11 for Figure 10 A magnified view of a portion of point C.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1000 vehicles;

[0037] Battery unit 100, controller 200, motor 300;

[0038] Battery cell assembly 10, battery cell 11, casing 110, end cap 111, housing 112, peripheral sidewall 1121, first wall 1122, electrode lead hole 1123, electrode assembly 120, first electrode tab 121, electrode body 122, positive current collector 1221, positive electrode body region 1221a, positive electrode blank region 1221b, negative current collector 1222, negative electrode body region 1222a, negative electrode blank region 1222b, separator 123, electrode terminal 130, main body 131, first part 1311, second part 1312, flange part 132, flange body 1321, weak part 1322, groove 1323, first current collector 140, through hole 141, first insulating member 150, second insulating member 160, sealing ring 170;

[0039] Box 20, first box 21, second box 22;

[0040] First busbar 30, weak point 31. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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).

[0047] 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 do not 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.

[0048] 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.

[0049] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0050] 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.

[0051] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0052] 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.

[0053] 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 type of battery cell to form the power system of an electrical device, in order to allow the internal pressure of the battery cell to 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.

[0054] 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.

[0055] 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 includes an electrode terminal comprising a main body and a flange. The main body passes through an electrode lead-out hole in the first wall of the outer casing. When the battery cell is depressurized, the main body can disconnect from the flange and move away from the electrode assembly to exit through the electrode lead-out hole. The electrode terminal is electrically connected to a first tab via a first current collector. The first current collector is stacked between the first tab and the electrode terminal, and the first current collector has a through hole opposite to the electrode terminal.

[0056] When such a battery cell experiences thermal runaway, the connection between the main body and the flange is at least partially disrupted by high temperature and / or high pressure, causing them to separate. High-temperature, high-pressure substances can flow through the through-hole to the electrode terminals, subsequently pushing the main body out of the electrode lead-out hole. This allows the electrode lead-out hole to be opened and used as a pressure relief port, as it is no longer blocked by the electrode terminals. The electrode terminals integrate current extraction and pressure relief functions. In this battery cell, the electrode lead-out hole on the first wall is used for pressure relief and electrode terminal installation. The pressure relief port and electrode terminals do not each occupy a portion of the first wall, thus ensuring both the current flow area and pressure relief area between the battery cell and the busbar. This battery cell can balance pressure relief and current flow capabilities.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Please refer to Figure 1 , Figure 1This 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.

[0064] 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.

[0065] 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.

[0066] In some embodiments, the battery cell assembly 10 is typically formed by arranging a plurality of battery cells 11.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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 house the battery cell assembly 10.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] Figure 3 This is a schematic diagram of the structure of a battery cell 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.

[0077] 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.

[0078] 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 application embodiment does not impose any special limitations on this.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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 120 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.

[0083] 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.

[0084] The electrode assembly 120 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked. In some embodiments, the electrode assembly 120 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 120.

[0085] 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.

[0086] 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.).

[0087] 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 0.3O2 (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.

[0088] 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.

[0089] 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.).

[0090] 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.

[0091] In some embodiments, the positive current collector 1221 may be made of aluminum, and the negative current collector 1222 may be made of copper.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0099] 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.

[0100] 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.

[0101] Figure 5 for Figure 3 The diagram shows the exploded structure of the battery cell 11. Figure 6 for Figure 3 The diagram shows a top view of the battery cell 11. Figure 7 For along Figure 6 A partial cross-sectional view of line AA. Figure 8 for Figure 7 A magnified view of a portion at point B. Please refer to [link / reference]. Figure 3 , Figures 5 to 8The battery cell 11 in this embodiment further includes an electrode terminal 130 and a first current collector 140. The housing 110 has a first wall 1122, which has an electrode lead-out hole 1123. The first wall 1122 is electrically connected to a second electrode tab. The electrode terminal 130 includes a main body 131 and a flange 132. The main body 131 is disposed in the electrode lead-out hole 1123. The flange 132 is connected to one end of the main body 131 along a first direction and is opposite to the first wall 1122. The flange 132 is located on the side of the first wall 1122 facing the electrode assembly 120. The connection position of the main body 131 and the flange 132 with the main body 131, along the first direction, is projected into the electrode lead-out hole 1123 on the first wall 1122. The electrode terminal 130 is configured such that the main body 131 can be disconnected from the flange 132 when the battery cell 11 is depressurized. The first direction is the axial direction of the electrode assembly 120. In the accompanying drawings of the embodiments of this application, the first direction can be referred to as the Z direction.

[0102] Along the first direction, the first current collector 140 is located between the electrode assembly 120 and the electrode terminal 130. The first tab 121 is electrically connected to the electrode terminal 130 through the first current collector 140. The first current collector 140 may be provided with a through hole 141, which is opposite to the electrode terminal 130.

[0103] The outer casing 110 can be a cylindrical casing 110, a square casing 110, a prismatic casing 110, or a casing 110 of 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, the outer casing 110 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 the electrolyte, among other components.

[0104] The first 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 wall, with the first wall 1122 and the second wall arranged opposite to each other along a first direction. Figure 5 In the middle, the first wall is located above the second wall.

[0105] 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 forms a first wall 1122, and the end wall of the housing 112 forms a second 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 forms a first wall 1122, and the end cap 111 forms a second wall. As an example, the housing 112 may have openings at both ends. 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 forms a first wall 1122, and the lower end cap 111 forms a second 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.

[0106] 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 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 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 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 wall 1122. In this example, the second electrode tab and the first 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 facing away from the first wall 1122. In this example, the second tab is directly or indirectly connected to the second wall to achieve electrical connection with the first 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 may also include a second current collector located between the electrode assembly 120 and the second wall. The second tab is electrically connected to the second wall through the second current collector, forming a current path of: second tab - second current collector - second wall - peripheral wall - first wall 1122.

[0107] 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. Electrode terminal 130 includes a body portion 131 and a flange portion 132. The body portion 131 passes through electrode lead-out hole 1123, and a portion of the body portion 131 may protrude from the first wall 1122. The flange portion 132 is connected to one end of the body portion 131 along a first direction ( Figure 7 The flange 132 extends toward the peripheral sidewall 1121 of the housing 110, and at least a portion of the flange 132 is disposed opposite to the first wall 1122. "The flange 132 is located on the side of the first wall 1122 facing the electrode assembly 120" means that the flange 132 is located inside the housing 110.

[0108] exist Figure 8 In this embodiment, electrode terminals 130 are stacked above first current collectors 140, and first current collectors 140 are stacked above first tabs 121 of electrode assembly 120. First tabs 121 are electrically connected to electrode terminals 130 via first current collectors 140. In this embodiment, the current flow path from first tabs 121 is: first tab 121 - first current collector 140 - electrode terminal 130. Specifically, first current collectors 140 can be connected to first tabs 121 and electrode terminals 130 by welding, abutting, bonding, or other methods. First current collectors 140 can be connected to the main body 131, and / or, first current collectors 140 can also be connected to flanges 132. Both first current collectors 140 and second current collectors are made of conductive material.

[0109] The through hole 141 extends through the first current collector 140 along the first direction. "The through hole 141 is opposite to the electrode terminal 130" means that the orthographic projection of the through hole 141 along the first direction onto the first wall 1122 falls within the orthographic projection of the electrode terminal 130 along the first direction onto the first wall 1122. The shape of the through hole 141 is not limited. For example, it can be circular, rectangular, elongated, waist-shaped, or cross-shaped, etc.

[0110] "The electrode terminal 130 is configured to disconnect the body portion 131 from the flange portion 132 when the battery cell 11 is depressurized" means that when the internal pressure or temperature of the battery cell 11 reaches a threshold, the electrode terminal 130 can be actuated, causing the connection between the body portion 131 and the flange portion 132 to be broken, i.e., the body portion 131 and the flange portion 132 are no longer connected. This threshold design varies depending on the design requirements. The threshold may depend on one or more of the materials of the positive electrode, negative electrode, electrolyte, and separator 123 in the battery cell 11. "Actuation" as used herein refers to the action of the electrode terminal 130, thereby allowing the internal pressure of the battery cell 11 to be released. The action of the electrode terminal 130 may include, but is not limited to, at least a portion of the electrode terminal 130 breaking, fracturing, or tearing.

[0111] "The orthographic projection of the main body 131 along the first direction onto the first wall 1122 falls within the electrode lead-out hole 1123," indicating that, taking a section perpendicular to the first direction as the cross-section, the cross-sectional area of ​​the main body 131 at all points is smaller than the opening area of ​​the electrode lead-out hole 1123. For example, if the main body 131 is cylindrical and the electrode lead-out hole 1123 is circular, the diameter of the main body 131 at all points is no larger than the diameter of the electrode lead-out hole 1123. Thus, when the battery cell 11 is depressurized, after the main body 131 separates from the flange 132, the movement of the main body 131 towards the outside of the casing will not be obstructed by the first wall 1122.

[0112] "The connection position between the flange portion 132 and the main body portion 131 is projected along the first direction into the electrode lead-out hole 1123," indicating that the connection position between the flange portion 132 and the main body portion 131 is not opposite to the first wall 1122. Thus, when the internal pressure or temperature of the battery cell 11 reaches the threshold, the connection position between the flange portion 132 and the main body portion 131 breaks. Even if part or all of the connection position between the flange portion 132 and the main body portion 131 is pushed out of the outer casing along with the main body portion 131, the connection position between the flange portion 132 and the main body portion 131 will not be blocked by the first wall 1122.

[0113] The pressure relief mechanism of the battery cell 11 in this embodiment is roughly as follows: When the battery cell 11 experiences thermal runaway, high-temperature and high-pressure substances are generated inside it. When the internal pressure or temperature of the battery cell 11 reaches a threshold, the connection between the main body 131 and the flange 132 is at least partially destroyed due to the high temperature and / or high pressure. This causes the electrode terminal 130 to be divided into two parts: the main body 131 and the flange 132. The main body 131 and the flange 132 are separated from each other and no longer have a connection. The high-temperature and high-pressure substances inside the battery cell 11 can flow to the electrode terminal 130 through the through hole 141. Then, the main body 131 moves under the impact of the high-temperature and high-pressure substances to detach from the electrode lead-out hole 1123 and rush out to the outside of the outer casing 110. The main body 131 no longer blocks the electrode lead-out hole 1123, so that the electrode lead-out hole 1123 is opened. The high-temperature and high-pressure substances are discharged to the outside of the outer casing 110 through the opened electrode lead-out hole 1123, thereby releasing the temperature and pressure inside the battery cell 11. The high-temperature and high-pressure substances mentioned in this article include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separator 123, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0114] In this embodiment, the battery cell 11 includes an electrode terminal 130 comprising a main body 131 and a flange 132. When the battery cell 11 is depressurized, the main body 131 can disconnect from the flange 132. Furthermore, the connection point between the main body 131 and the flange 132, along a first direction, projects onto the first wall 1122 within the electrode lead-out hole 1123. This allows the main body 131, after separating from the flange 132, to detach from the electrode lead-out hole 1123 and exit the outer casing 110 under the impact of high-temperature, high-pressure substances, thus opening the electrode lead-out hole 1123 to achieve pressure relief. Therefore, the electrode terminal 130 in this embodiment integrates both current extraction and pressure relief functions. On the one hand, there is no need to set up an additional pressure relief mechanism, which reduces the number of components in the battery cell 11. On the other hand, the same end of the battery cell 11 leads out current and realizes pressure relief. Thus, when the power system of the electrical equipment is composed of the battery cell 11 of this embodiment, the space occupied by the busbar (see below) used to connect with the electrode terminal 130 and the first wall 1122 to lead 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 wall 1122. This can have a positive effect on improving the structural compactness of the electrical equipment.

[0115] The first current collector 140 enables electrical connection between the first tab 121 and the electrode terminal 130. Furthermore, the through hole 141 ensures that the first current collector 140 does not obstruct high-temperature, high-pressure substances, thus guaranteeing pressure relief.

[0116] Furthermore, the battery device of the electrical equipment composed of the battery cells 11 of this embodiment can have other functional structures arranged on the side away from the first wall 1122, which increases the possibilities for the structural design of the electrical equipment. For example, when the battery cells 11 of this embodiment are used to compose the battery device of an electric vehicle, the battery device may include a heat exchange assembly, which is arranged sequentially with the battery cells 11 along the first direction, and the heat exchange assembly is located on the side of the electrode assembly 120 away from the first wall 1122 and exchanges heat with the battery cells 11.

[0117] Furthermore, in this embodiment, the electrode lead-out hole 1123 used for mounting the electrode terminal 130 is used as a pressure relief port when it is open. In this way, the electrode terminal 130 and the pressure relief port share part of the area of ​​the first wall 1122, which alleviates the conflict caused by the electrode terminal 130 and the pressure relief port occupying part of the area respectively, which cannot simultaneously meet the overcurrent requirement and the pressure relief requirement. The battery cell 11 in this embodiment can take into account both overcurrent capability and pressure relief capability.

[0118] It is understandable that the electrode terminal 130 can achieve actuation in various ways.

[0119] According to some embodiments of this application, the flange portion 132 may include a flange body 1321 and a weak portion 1322 disposed along the inner peripheral side of the flange body 1321. The weak portion 1322 is projected along a first direction into the electrode lead-out hole 1123. The strength of the weak portion 1322 is lower than the strength of the flange body 1321. The weak portion 1322 is configured to crack when the battery cell 11 is depressurized.

[0120] Please combine Figure 5 Both the flange body 1321 and the weak portion 1322 are annular structures. The weak portion 1322 is located on the inner circumference of the flange body 1321 and is connected to one end of the main body 131 along the first direction. That is, the main body 131 is connected to the flange body 1321 through the weak portion 1322. The flange body 1321 and the weak portion 1322 can be integrally formed, or they can be joined together by bonding, snap-fitting, welding, or other methods.

[0121] Because the strength of the weak portion 1322 is lower than that of the flange body 1321, the weak portion 1322 can crack under the action of internal pressure when the internal pressure or temperature of the battery cell 11 reaches a threshold, thereby releasing the internal pressure of the battery cell 11. "The orthographic projection of the weak portion 1322 along the first direction onto the first wall 1122 falls within the electrode lead-out hole 1123" indicates that the weak portion 1322 is directly opposite the electrode lead-out hole 1123 but not opposite the first wall 1122, and at least a portion of the flange body 1321 is opposite to the periphery of the electrode lead-out hole 1123 on the first wall 1122. Thus, when the internal pressure or temperature of the battery cell 11 reaches the threshold, after the weak portion 1322 cracks, even if part or all of the weak portion 1322 is still connected to the main body 131 and ejects out of the casing with the main body 131, the weak portion 1322 will not be obstructed by the first wall 1122, allowing the main body 131 to smoothly detach from the electrode lead-out hole 1123.

[0122] Using this technical solution, when the internal pressure or temperature of the battery cell 11 reaches a threshold, the electrode terminal 130 cracks along the weak part 1322. Thus, under the impact of high temperature and high pressure material, the weak part 1322 on the flange 132 will move along with the main body 131 connected to it. In addition, the orthographic projection of the weak part 1322 along the first direction onto the first wall 1122 falls into the electrode lead-out hole 1123, so that the process of the weak part 1322 rushing out of the outer casing 110 will not be interfered with by the first wall 1122. Therefore, the main body 131 can be smoothly removed from the electrode lead-out hole 1123 to ensure that pressure relief can be achieved smoothly.

[0123] There are various ways to make the strength of the weak portion 1322 lower than the strength of the flange body 1321. A groove, a notch, a through hole or other structure can be made in a predetermined area of ​​the flange portion 132 to reduce the strength of a local position of the flange portion 132, thereby forming a weak portion 1322 on the flange portion 132. The predetermined area is located at one end of the flange portion 132 that is connected to the main body portion 131.

[0124] Figure 9 This is a schematic cross-sectional view of the electrode terminal 130 according to some embodiments of this application. Please refer to [link / reference] for some embodiments of this application. Figure 9 The dimension h1 of the weak part 1322 along the first direction is smaller than the dimension h2 of the flange body 1321 along the first direction.

[0125] The dimension of the weak portion 1322 along the first direction can be understood as the thickness of the weak portion 1322, and the dimension of the flange body 1321 along the first direction can be understood as the thickness of the flange body 1321. For example, a thinning process can be performed on a predetermined area of ​​the flange portion 132, with the thinned portion of the flange portion 132 forming the weak portion 1322, and the unthinned portion forming the flange body 1321. For example... Figure 9 As shown, a groove 1323 can be provided at one end of the flange portion 132 that is connected to the main body portion 131, and a weak portion 1322 is formed in the area where the groove 1323 is provided on the flange portion 132.

[0126] With this technical solution, under the premise of consistent materials, the thickness of the weak part 1322 is less than the thickness of the flange body 1321, and the weak part 1322 is the weakest position of the flange part 132.

[0127] In some other embodiments of this application, a predetermined area of ​​the flange 132 may be material-treated to make the strength of that area weaker than that of other areas, thus forming a weak portion 1322.

[0128] Figure 10 This is a partial cross-sectional schematic diagram of a battery cell 11 according to other embodiments of this application. Figure 11 for Figure 10 A partially enlarged schematic diagram at point C. According to some embodiments of this application, the melting point of the material of the flange portion 132 may be lower than the melting point of the material of the main body portion 131.

[0129] The melting point of the material of the flange portion 132 can be lower than the melting point of the material of the main body portion 131, meaning that when the melting point temperature of the material of the flange portion 132 is reached, the flange portion 132 will melt, but the main body portion 131 will not melt. Alternatively, the melting point of the material of the entire flange portion 132 can be lower than the melting point of the material of the main body portion 131. Or, the flange portion 132 can include a flange body 1321 and a weak portion 1322 provided along the inner circumference of the flange body 1321. The melting point of the material of the weak portion 1322 can be lower than the melting point of the material of the main body portion 131, while the melting point of the material of the flange body 1321 can be no lower than the melting point of the material of the main body portion 131.

[0130] The pressure relief mechanism of the battery cell 11 in this embodiment is roughly as follows: When the internal temperature of the battery cell 11 reaches a threshold, since the melting point of the material of the flange portion 132 can be lower than the melting point of the material of the main body portion 131, the flange portion 132 will melt before the main body portion 131, and the main body portion 131 and the flange portion 132 will break apart from each other. Then, the main body portion 131 moves under the impact of the high temperature and high pressure material to detach from the electrode lead-out hole 1123 and rush out to the outside of the outer casing 110, so that the electrode lead-out hole 1123 opens, and the high temperature and high pressure material is discharged to the outside of the outer casing 110 through the opened electrode lead-out hole 1123, thereby releasing the internal temperature and pressure of the battery cell 11.

[0131] According to some embodiments of this application, the melting point of the material of the flange portion 132 may be less than or equal to 300°C. The flange portion 132 may be selected from at least one of the following materials: polyethylene, polypropylene, polystyrene, ABS plastic, tin alloy, etc. In this example, the main body portion 131 is electrically connected to the first electrode tab 121.

[0132] Considering that when the battery cell 11 experiences thermal runaway, the discharged high-temperature and high-pressure material can typically reach 400°C to 800°C, this embodiment designs the flange portion 132 to have a melting point less than or equal to 300°C. The high-temperature and high-pressure material can rapidly melt the flange portion 132, thus enabling the electrode terminal 130 to respond quickly and achieve pressure relief.

[0133] According to some embodiments of this application, the melting point of the material of the flange portion 132 can be greater than or equal to 60°C and less than or equal to 180°C. The melting point of the material of the flange portion 132 can be 60°C to 180°C, for example, a range of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, or any combination thereof. In a specific example, the melting point of the material of the flange portion 132 can be greater than or equal to 80°C and less than or equal to 180°C.

[0134] On the one hand, by designing the material of the flange portion 132 to have a melting point greater than or equal to 60°C, the melting point of the material of the flange portion 132 is not too low, which helps to prevent the flange portion 132 from melting before thermal runaway occurs, allowing the electrode terminal 130 to respond accurately to achieve pressure relief. On the other hand, by designing the melting point of the material of the flange portion 132 to be less than or equal to 180°C, which is higher than the normal operating temperature of the battery cell 11 but not too high, the electrode terminal 130 can respond in a timely manner to achieve pressure relief.

[0135] According to some embodiments of this application, the battery cell 11 may further include a second current collector (not shown). The second current collector is electrically connected to the first wall 1122. The first current collector 140 and the second current collector have opposite polarities. 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 is located on the side of the electrode assembly 120 facing the first wall 1122, and the second current collector can be directly welded to the first 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 is located on the side of the electrode assembly 120 away from the first wall 1122, and the second current collector can be located between the electrode assembly 120 and the second wall and connected to the second wall.

[0136] In some embodiments, please continue reading Figure 8 and Figure 11 The battery cell 11 may further include a first insulating member 150 and a second insulating member 160. The first insulating member 150 is located outside the housing 110 and is positioned between the main body 131 and the first wall 1122 to provide insulation between the main body 131 and the first wall 1122. The second insulating member 160 is located inside the housing 110 and, along a first direction, is positioned between the first wall 1122 and the flange 132 to provide insulation between the flange 132 and the first wall 1122.

[0137] In some embodiments, the battery cell 11 may further include a sealing ring 170, a portion of which is located at the electrode lead-out hole 1123 and surrounds the main body 131 to seal the gap between the main body 131 and the electrode lead-out hole 1123. The sealing ring 170 may be made of insulating materials such as rubber or plastic to insulate the main body 131 from the first wall 1122.

[0138] 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.

[0139] 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.

[0140] According to some embodiments of this application, the battery device may further include a busbar. The busbar includes a first busbar 30 and a second busbar (not shown in the figure). The first busbar 30 is stacked on one end of the main body 131 away from the electrode assembly 120 along a first direction and connected to the main body 131. The first busbar 30 is provided with a weak region 31, which is configured to break when the battery cell 11 is depressurized, and the weak region 31 is located outside the main body 131 in the orthogonal projection of the first wall 1122 along the first direction.

[0141] A busbar is a component capable of conducting current. The second busbar can be connected to the first wall 1122 by welding. It can be understood that the first busbar 30 and the second busbar are located on the same side of the battery cell 11. As an example, the electrode terminal 130 of one battery cell 11 can be electrically connected to the first wall 1122 of another battery cell 11 through the first busbar 30, and the first wall 1122 of one battery cell 11 can be electrically connected to the electrode terminal 130 of another battery cell 11 through the second busbar, enabling multiple battery cells 11 to be connected in series. As an example, the electrode terminal 130 of one battery cell 11 can be electrically connected to the electrode terminal 130 of another battery cell 11 through the first busbar 30, and the first wall 1122 of one battery cell 11 can be electrically connected to the first wall 1122 of another battery cell 11 through the second busbar, enabling multiple battery cells 11 to be connected in parallel.

[0142] In some embodiments, the main body 131 includes a first portion 1311 and a second portion 1312. The first portion 1311 passes through the electrode lead-out hole 1123, and the second portion 1312 is located on the side of the first portion 1311 opposite to the flange portion 132. The second portion 1312 is located outside the housing 110 and connected to the first busbar 30. The first portion 1311 and the second portion 1312 can be integrally formed, or the first portion 1311 and the second portion 1312 can be connected by welding, bonding, snap-fitting, or other methods.

[0143] The weakest point 31 is the weakest part of the first busbar 30. The strength of the first busbar 30 at the weakest point 31 is lower than that at other parts of the first busbar 30. Thus, when the internal pressure or temperature of the battery cell 11 reaches a threshold, the main body 131 and the flange 132 of the electrode terminal 130 separate from each other. Under the impact of high temperature and high pressure, the main body 131 moves in the first direction away from the electrode assembly 120 to impact the outside of the outer casing 110, which in turn causes the first busbar 30 connected to the main body 131 to deform, causing the first busbar 30 to break along the weakest point 31. This breaks the series or parallel connection between the battery cell 11 and other batteries.

[0144] When this technical solution is adopted, when the battery cell 11 experiences thermal runaway, the main body 131 of the electrode terminal 130 is dislodged from the electrode lead-out hole 1123 and rushes out of the outer casing 110. At this time, the weak area 31 of the first busbar 30 is damaged, which breaks the circuit between the battery cell 11 and other battery cells 11. This helps to suppress the chain reaction caused by the further development of thermal runaway.

[0145] According to some embodiments of this application, such as Figure 7 and Figure 8 As shown, the flange portion 132 includes a flange body 1321 and a weak portion 1322 disposed along the inner circumferential side of the flange body 1321. The orthographic projection of the weak portion 1322 along the first direction onto the first wall 1122 falls within the electrode lead-out hole 1123. The weak portion 1322 is configured to crack when the battery cell 11 is depressurized. The orthographic projection of the weak region 31 along the first direction onto the first wall 1122 can be further away from the main body 131 than the orthographic projection of the weak portion 1322 along the first direction onto the first wall 1122.

[0146] In other words, when the flange portion 132 is provided with a weak portion 1322, the weak area 31 on the first busbar 30 is located on the side of the weak portion 1322 away from the main body portion 131 in a direction perpendicular to the first direction. In this embodiment, when the internal pressure or temperature of the battery cell 11 reaches a threshold, the electrode terminal 130 breaks along the weak portion 1322, the main body 131 separates from the flange portion 132, and the main body 131 moves away from the electrode assembly 120 in the first direction under the impact of high temperature and high pressure material to rush towards the outside of the outer casing 110, thereby causing the first busbar 30 connected to the main body 131 to deform, so that the first busbar 30 breaks along the weak area 31, and the breakage position of the first busbar 30 is located outside the damage position of the electrode terminal 130. In this way, the part of the first busbar 30 connected to other battery cells 11 after the breakage will not cover the main body 131 of the battery cell 11, so as not to affect the punching action of the main body 131, so that the main body 131 can smoothly detach from the electrode lead hole 1123 to open the electrode lead hole 1123.

[0147] With this technical solution, the part of the first busbar 30 that is connected to other battery cells 11 after it breaks during depressurization will not cover the main body 131 of the battery cell 11, so as to further ensure that the main body 131 can be pushed out smoothly, thereby ensuring that depressurization is successfully achieved.

[0148] There are various ways in which the first busbar 30 forms the weak area 31. For example, a localized area of ​​the first busbar 30 may be treated with a material such that the strength of that area is weaker than that of other areas. Another example is that a localized area of ​​the first busbar 30 may be thinned, and the thinned portion of the first busbar 30 forms the weak area 31.

[0149] According to some embodiments of this application, the weak area 31 can be a hollowed-out portion provided in the first busbar 30.

[0150] In other words, through holes are made at local locations of the first busbar 30 to reduce the strength of the first busbar 30 at local locations, thereby forming a weak area 31 at the local locations of the first busbar 30. The number and shape of the through holes are not limited; there can be one, two, three, four, five or more through holes, and the shape of the through holes can be circular, square, rectangular, etc.

[0151] Of course, in other embodiments of this application, grooves, grooves, or other structures may be formed at local locations of the first busbar 30 to reduce the strength of local locations of the first busbar 30.

[0152] 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.

[0153] The electrical equipment includes vehicles (such as vehicles, 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, because it uses any of the above-mentioned battery cells 11, has all the beneficial effects of the battery cells 11, which will not be elaborated here.

[0154] 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.

[0155] 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.

[0156] It is understood that the energy storage 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.

[0157] 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.

[0158] 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.

[0159] Example 1

[0160] like Figure 3 , Figures 5 to 8 As 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 wall 1122, and the first 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 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, thereby achieving electrical connection with the first wall 1122.

[0161] The electrode terminal 130 includes a main body 131 and a flange 132. The main body 131 passes through the electrode lead-out hole 1123 and protrudes from the first wall 1122. The flange 132 is located inside the housing 110, and is connected to the lower end of the main body 131 and extends toward the peripheral sidewall 1121 of the housing 112. A first current collector 140 is stacked between the electrode terminal 130 and the first tab 121, and the first tab 121 is electrically connected to the electrode terminal 130 through the first current collector 140. The first current collector 140 may have a through hole 141, which is opposite to the electrode terminal 130. A groove 1323 is formed at one end of the flange portion 132 that connects to the main body portion 131. A weak portion 1322 is formed in the area where the groove 1323 is provided on the flange portion 1322. The weak portion 1322, along the axial direction of the cylindrical battery cell 11, is projected entirely into the electrode lead-out hole 1123 on the first wall 1122. When the battery cell 11 is depressurized, the weak portion 1322 can break, causing the main body portion 131 to separate from the flange portion 132, and the main body portion 131 can move in a direction away from the electrode assembly 120 to disengage from the electrode lead-out hole 1123.

[0162] The electrode terminal 130 of the cylindrical battery cell 11 is connected to the electrode terminal 130 of another cylindrical battery cell 11 or the first wall 1122 via the first busbar 30. A through hole is formed in a local position of the first busbar 30, and a weak area 31 is formed in a local position of the first busbar 30. The orthographic projection of the weak area 31 along the axial direction of the cylindrical battery cell 11 onto the first wall 1122 is farther away from the main body 131 than the orthographic projection of the weak portion 1322 along the axial direction of the cylindrical battery cell 11 onto the first wall 1122.

[0163] Example 2

[0164] Example 2 is similar to Example 1, except that: Figure 3 , Figure 10 and Figure 11 As shown, the melting point of the material of the flange portion 132 is lower than that of the material of the main body portion 131. The melting point of the material of the flange portion 132 can be 80°C to 180°C. When the internal temperature of the battery cell 11 reaches the threshold, the flange portion 132 melts before the main body portion 131, and the main body portion 131 and the flange portion 132 break apart from each other. Then, the main body portion 131 moves under the impact of high temperature and high pressure material to detach from the electrode lead-out hole 1123 and rush out to the outside of the outer casing 110, so that the electrode lead-out hole 1123 opens to achieve discharge.

[0165] 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 wall, and the first wall is provided with electrode lead-out holes; 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 wall; An electrode terminal includes a body portion and a flange portion. The body portion is disposed at the electrode lead-out hole. The flange portion is connected to one end of the body portion along a first direction and is opposite to a first wall. The flange portion is located on the side of the first wall facing the electrode assembly. The orthographic projection of the body portion and the flange portion to the body portion along the first direction onto the first wall falls within the electrode lead-out hole. The electrode terminal is configured such that the body portion can be disconnected from the flange portion when the battery cell is depressurized. The first direction is the axial direction of the electrode assembly. A first current collector is located between the electrode assembly and the electrode terminal along the first direction. The first tab is electrically connected to the electrode terminal through the first current collector. The first current collector has a through hole, which is opposite to the electrode terminal.

2. The battery cell according to claim 1, characterized in that, The flange portion includes a flange body and a weak portion disposed along the inner circumferential side of the flange body. The orthographic projection of the weak portion along the first direction onto the first wall falls within the electrode lead-out hole. The strength of the weak portion is lower than the strength of the flange body. The weak portion is configured to crack when the battery cell is depressurized.

3. The battery cell according to claim 2, characterized in that, The dimension of the weak portion along the first direction is smaller than the dimension of the flange body along the first direction.

4. The battery cell according to claim 1, characterized in that, The melting point of the material of the flange portion is lower than that of the material of the body portion.

5. The battery cell according to claim 4, characterized in that, The material of the flange portion has a melting point of less than or equal to 300°C.

6. The battery cell according to claim 5, characterized in that, The material of the flange portion has a melting point greater than or equal to 60°C and less than or equal to 180°C.

7. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 6.

8. The battery device according to claim 7, characterized in that, The battery device further includes a first busbar stacked on one end of the main body away from the electrode assembly along the first direction and connected to the main body. The first busbar has a weak area configured to break when the battery cell is depressurized, and the orthographic projection of the weak area along the first direction onto the first wall is located outside the main body.

9. The battery device according to claim 8, characterized in that, The flange portion includes a flange body and a weak portion disposed along the inner circumferential side of the flange body. The orthographic projection of the weak portion along the first direction onto the first wall falls within the electrode lead-out hole. The strength of the weak portion is lower than the strength of the flange body. The weak portion is configured to crack when the battery cell is depressurized. The orthographic projection of the weak area along the first direction onto the first wall is farther away from the main body than the orthographic projection of the weak portion along the first direction onto the first wall.

10. The battery device according to claim 8 or 9, characterized in that, The weak area is the hollowed-out part located in the first busbar.

11. An electrical appliance, characterized in that, The electrical equipment includes a battery device as described in any one of claims 7 to 10, the battery device being used to provide electrical energy.

12. An energy storage device, characterized in that, The energy storage device includes a battery device as described in any one of claims 7 to 10, the battery device being used to store electrical energy.

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