Battery cell, battery, and electrical device

Abstract

The present application discloses a battery cell, a battery, and an electrical device. The battery cell comprises a casing and an electrode assembly. The casing comprises a first casing wall and a second casing wall which are oppositely arranged in a first direction, and the area of a second outer surface of the second casing wall is smaller than or equal to the area of a first outer surface of the first casing wall. The electrode assembly is accommodated in the casing and comprises a body part and a first tab, the body part is located between the first casing wall and the second casing wall in the first direction, the first tab extends out from at least one end of the body part in a second direction, and the second direction intersects with the first direction. The distance between the first casing wall and the second casing wall in the first direction is D1 mm, the area of the second outer surface of the second casing wall is S mm2, and S is 36 to 500 times the square of D1.

Description

Battery cells, batteries, and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311458313.7, filed on November 3, 2023, entitled “Battery Cell, Battery, and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Battery cells are widely used in electronic devices such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0005] In the development of battery technology, how to improve the cycle performance of battery cells is a research direction in battery technology.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery, and an electrical device, which can enable the battery cell to have both good heat dissipation efficiency and good rigidity and structural strength, thereby improving the cycle performance of the battery cell.

[0008] In a first aspect, the present application provides a battery cell comprising a housing and an electrode assembly. The housing comprises a first shell wall and a second shell wall arranged opposite to each other along a first direction, wherein the area of ​​the second outer surface of the second shell wall is less than or equal to the area of ​​the first outer surface of the first shell wall. The electrode assembly is housed in the housing and comprises a main body and a first tab, wherein the main body is located between the first shell wall and the second shell wall in the first direction, and the first tab extends from at least one end of the main body along a second direction, and the second direction intersects with the first direction. The spacing between the first shell wall and the second shell wall along the first direction is D1 mm, and the area of ​​the second outer surface of the second shell wall is S mm 2 , S is 36 to 500 times the square of D1.

[0009] In the embodiments of the present application, S is set to 36 to 500 times the square of D1, enabling the battery cells to achieve both good heat dissipation efficiency and good rigidity and structural strength. Specifically, S is set to be greater than or equal to 36 times the square of D1 to improve the heat dissipation efficiency of the battery cells, reduce heat accumulation within the battery cells, lower the temperature rise of the battery cells during charge and discharge, and improve the cycle performance and cycle life of the battery cells. In the embodiments of the present application, S is set to be less than or equal to 500 times the square of D1 to improve the rigidity and structural strength of the battery cells, reduce deformation of the battery cells when subjected to external impact, and improve the reliability of the battery cells.

[0010] In some embodiments, S / D1 2 The range of 45-175 can further balance the cycle performance and reliability performance of the battery cell, reduce the temperature rise of the battery cell, and reduce the risk of deformation of the battery cell.

[0011] In some embodiments, the dimension of the second shell wall along the second direction is D2 mm, the dimension of the second shell wall along the third direction is D3 mm, the first direction, the second direction and the third direction are perpendicular to each other, and D1, D2 and D3 satisfy: D2>D3>D1.

[0012] The main body may be the main factor determining the capacity of the battery cell. D2 is related to the size of the main body along the second direction, and D3 is related to the size of the main body along the third direction. The first tab extends from the end of the main body along the second direction, which will take up additional space in the second direction but not in the third direction. The embodiment of the present application can make the main body have a larger size along the second direction, thereby reducing the ratio of the size of the first tab along the second direction to the size of the main body along the second direction, improving space utilization, and increasing the energy density of the battery cell. D1 is smaller than D2 and D3, which can shorten the heat transfer path, improve heat dissipation efficiency, and improve the cycle performance and cycle life of the battery cell.

[0013] In some embodiments, D2 / D3 is 4-10.2; alternatively, D2 / D3 is 5-7. The present invention can balance the space utilization of the battery cell and the current carrying capacity of the first tab, thereby improving the space utilization and the energy density of the battery cell while the current carrying capacity of the first tab meets the requirements.

[0014] In some embodiments, D3 / D1 is 3-7; alternatively, D3 / D1 is 3-5. The embodiments of the present application can improve the heat dissipation efficiency of the battery cells, reduce the temperature rise of the battery cells during charging and discharging, improve the rigidity and structural strength of the battery cells, reduce deformation of the battery cells when subjected to external impacts, and improve the reliability of the battery cells.

[0015] In some embodiments, D2 is 300-3000; alternatively, D2 is 500-1000. In the embodiments of the present application, D2 is greater than or equal to 300, which can enable the battery cells to have larger dimensions in the second direction, thereby reducing the number of battery cells in the battery, simplifying the battery molding process, and improving the battery's energy density. D2 is less than or equal to 3000, which can reduce the difference in the conductive path between the two ends of the main body and the first tab, thereby reducing heat generation.

[0016] In some embodiments, the energy of the battery cell is 150×D1×S×10 -6 -600×D1×S×10 -6 The unit of energy is Wh. By defining the energy of a battery cell according to D1×S, the embodiment of the present application can achieve a certain balance between the heat dissipation efficiency and heat generation of the battery cell, reduce the temperature rise of the battery cell during the charge and discharge process, and improve the cycle performance of the battery cell.

[0017] In some embodiments, the thickness of the second shell wall is 0.1 mm to 0.8 mm; alternatively, the thickness of the second shell wall is 0.2 mm to 0.5 mm; further alternatively, the thickness of the second shell wall is 0.3 mm. This embodiment of the present application can balance the strength and weight of the second shell wall, improving the reliability of the battery cell and increasing the energy density of the battery cell.

[0018] In some embodiments, the area of ​​the second outer surface of the second shell wall is smaller than the area of ​​the first outer surface of the first shell wall. A first recess is defined at an end of the shell along the second direction, the first recess being recessed from the second shell wall toward the first shell wall. In the first direction, at least a portion of the first tab is located between a bottom wall of the first recess and the first shell wall.

[0019] The first electrode tab requires less space in the first direction, so a first recess may be provided on the outer side of the housing, which can reduce the volume of the battery cell and improve the volume energy density of the battery cell.

[0020] In some embodiments, the housing includes two third shell walls disposed opposite each other along a third direction, each third shell wall being connected to the first shell wall and the second shell wall, with each third shell wall being perpendicular to the first, second, and third directions. In the third direction, at least a portion of the first tab is located between the two third shell walls. In the third direction, the first tab has a dimension of L1 mm, the spacing between the two third shell walls is L2 mm, and L1 / L2 is 0.2-0.9.

[0021] In this embodiment of the present application, L1 / L2 is limited to greater than or equal to 0.2 to increase the current capacity of the first tab and reduce the heat generated by the first tab. In this embodiment of the present application, L1 / L2 is limited to less than or equal to 0.9 to reduce the risk of short circuit between the first tab and the third shell wall.

[0022] In some embodiments, L1 / L2 is 0.5-0.8, so as to further increase the current carrying capacity of the first electrode tab and reduce the risk of short circuit between the first electrode tab and the third shell wall.

[0023] In some embodiments, in the third direction, the size of the main body is L3 mm, and L3 / L2 is 0.9-0.99; optionally, L3 / L2 is 0.95-0.98.

[0024] The embodiment of the present application can improve the space utilization of the main body in the third direction and reduce the difficulty of installing the main body between the two third shell walls.

[0025] In some embodiments, the battery cell further includes a first electrode lead-out member disposed on the first housing wall and electrically connected to the first tab. At least a portion of the first electrode lead-out member is located outside the first housing wall; in the first direction, a projection of the portion of the first electrode lead-out member located outside the first housing wall is at least partially located within a projection of the first recess.

[0026] When a plurality of battery cells are arranged along the first direction, the first recess of one battery cell can avoid the first electrode lead-out piece of another battery cell, thereby improving space utilization and enhancing the energy density of the battery.

[0027] In some embodiments, the battery cell further includes a first electrode lead-out member disposed on the first housing wall. The first electrode lead-out member includes a first connecting plate housed within the housing. At least a portion of the first electrode tab is stacked and connected to the first connecting plate in the first direction. In the third direction, the first electrode tab has a dimension of L1 mm, the first connecting plate has a dimension of L4 mm, and L1 / L4 is 0.6-1; optionally, L1 / L4 is 0.8-0.9. The first, second, and third directions are perpendicular to each other.

[0028] In this embodiment of the present application, L1 / L4 is limited to greater than or equal to 0.6 to increase the connection area between the first tab and the first connecting plate, improve the flow capacity between the first tab and the first connecting plate, and reduce temperature rise. In this embodiment of the present application, L1 / L4 is limited to less than or equal to 1 to reduce the space wasted by the first tab and improve space utilization.

[0029] In some embodiments, the battery cell further includes a first electrode lead-out member disposed on the first shell wall. The first electrode lead-out member includes a first connecting plate, a second connecting plate, a third connecting plate, a first electrode terminal, and a first terminal plate. The first connecting plate is housed in the shell, and at least a portion of the first electrode tab is located on a side of the first connecting plate facing away from the first shell wall and is connected to the first connecting plate. The second connecting plate extends from an end of the first connecting plate close to the main body toward the first shell wall. The third connecting plate is connected to an end of the second connecting plate away from the first connecting plate and is located between the first shell wall and the first connecting plate. The first electrode terminal is connected to the third connecting plate and passes through the first shell wall. The first terminal plate is located on a side of the first shell wall facing away from the first electrode tab and is connected to the first electrode terminal.

[0030] The first terminal plate is provided to facilitate electrical connection with an external conductive structure, thereby improving the current carrying capacity.

[0031] In some embodiments, in the first direction Z, a projection of the first terminal plate is located within a projection of the first recess.

[0032] When a plurality of battery cells are arranged along the first direction, the first recess of one battery cell can avoid the first terminal plate of another battery cell, thereby improving space utilization and enhancing the energy density of the battery.

[0033] In some embodiments, the first terminal plate includes a first terminal portion and a second terminal portion, the first terminal portion being connected to the first electrode terminal, and the second terminal portion being protruding from a surface of the first terminal portion facing away from the first housing wall. Both the first terminal portion and the second terminal portion can be used to connect to the busbar component, and the provision of the second terminal portion can increase the connection area between the first terminal plate and the busbar component.

[0034] In some embodiments, the battery cell further includes an insulating bracket housed within the housing and disposed along the second direction with the main body. A first receiving recess is disposed on a side of the insulating bracket facing the main body. At least a portion of the first tab extends into and is bent within the first receiving recess.

[0035] The wall of the first accommodating recess can guide the first tab to bend, so as to reduce the space occupied by the first tab in the second direction and reduce the risk of the first tab contacting the housing during the bending process, thereby improving reliability.

[0036] In some embodiments, the battery cell further includes a first electrode lead-out member disposed on the first housing wall. In a first direction, a portion of the insulating bracket is located between the first electrode lead-out member and the first housing wall. The first electrode lead-out member and the first housing wall can constrain the insulating bracket in the first direction, reducing the risk of the insulating bracket swaying within the housing when the battery cell is subjected to external impact.

[0037] In some embodiments, the battery cell further includes a first electrode lead-out member and an insulating member. The first electrode lead-out member is disposed on the first shell wall and electrically connected to the first electrode tab. The insulating member is used to insulate the electrode lead-out member from the first shell wall.

[0038] In some embodiments, the first shell wall is provided with a pressure relief mechanism; in the first direction, the pressure relief mechanism and the main body do not overlap. This embodiment of the present application can reduce the risk of the main body blocking the pressure relief mechanism when a battery cell experiences thermal runaway, thereby providing timely pressure relief and improving the reliability of the battery cell.

[0039] In some embodiments, a minimum distance H1 between the pressure relief mechanism and the edge of the first shell wall is 2 mm to 5 mm.

[0040] In this embodiment of the present application, H1 is set to be greater than or equal to 2 mm to reduce the force on the pressure relief mechanism when the edge of the first shell wall is impacted, thereby reducing the risk of the pressure relief mechanism rupturing or failing, and improving reliability. H1 is set to be less than or equal to 5 mm to reduce the risk of the pressure relief mechanism being blocked by the main body.

[0041] In some embodiments, the first shell wall is provided with a liquid injection hole, and the minimum distance H2 between the pressure relief mechanism and the liquid injection hole is greater than or equal to 1 mm. This embodiment of the present application can reduce the stress transmitted to the pressure relief mechanism during liquid injection, reduce the risk of rupture or failure of the pressure relief mechanism, and improve reliability.

[0042] In some embodiments, the AC internal resistance of the battery cell is less than or equal to 1 milliohm. A smaller AC internal resistance of the battery cell can reduce heat generation of the battery cell and improve the cycle performance of the battery cell.

[0043] In some embodiments, the second shell wall is made of aluminum or steel, and the first shell wall is made of aluminum or steel. Aluminum and steel have high strength and good thermal conductivity. Using aluminum or steel shell walls can improve the cycle performance and reliability of the battery cells.

[0044] In some embodiments, the electrode assembly includes a plurality of first electrode sheets and a plurality of second electrode sheets, wherein the polarity of the first electrode sheets is opposite to that of the second electrode sheets, and the plurality of first electrode sheets and the plurality of second electrode sheets are alternately stacked along a first direction. The first electrode sheet includes a first current collector and a first active material layer coated on the surface of the first current collector, and the second electrode sheet includes a second current collector and a second active material layer coated on the surface of the second current collector. The main body includes a portion of the first current collector coated with the first active material layer, a portion of the second current collector coated with the second active material layer, the first active material layer, and the second active material layer, and the first electrode tab includes a portion of the first current collector not coated with the first active material layer.

[0045] In some embodiments, the housing includes a shell and a cover plate arranged along a first direction, the shell having an opening, and the cover plate covering the opening. The shell includes a second shell wall, and the cover plate includes a first shell wall. The shell and the cover plate can overlap each other to form a storage space for the electrode assembly. The shell and the cover plate are easy to form and assemble.

[0046] In some embodiments, a surface of the cover plate facing the housing is provided with a positioning groove, and a portion of the main body is accommodated in the positioning groove. During assembly, the positioning groove can position the main body, thereby improving assembly efficiency.

[0047] In a second aspect, an embodiment of the present application provides a battery comprising a plurality of battery cells provided according to any embodiment of the first aspect.

[0048] In a third aspect, an embodiment of the present application provides an electrical device, which includes a battery provided according to any embodiment of the second aspect, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0050] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0051] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application;

[0052] FIG3 is a schematic structural diagram of batteries provided in other embodiments of the present application;

[0053] FIG4 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0054] FIG5 is a schematic cross-sectional view taken along the AA direction in FIG4 ;

[0055] FIG6 is an enlarged schematic diagram of the frame in FIG5 ;

[0056] FIG7 is a schematic cross-sectional view taken along the BB direction in FIG4 ;

[0057] FIG8 is a schematic diagram of an electrode assembly of a battery cell provided in some embodiments of the present application;

[0058] FIG9 is a schematic cross-sectional view taken along the CC direction of FIG8 ;

[0059] FIG10 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0060] FIG11 is a partial cross-sectional schematic diagram of a battery cell at a liquid injection hole provided by some embodiments of the present application;

[0061] FIG12 is a schematic structural diagram of an insulating bracket provided in some embodiments of the present application;

[0062] FIG13 is a schematic structural diagram of the insulating bracket of FIG12 from another perspective;

[0063] FIG14 is a schematic cross-sectional view taken along the EE direction of FIG13;

[0064] FIG15 is a schematic cross-sectional view of a cover plate of a battery cell provided in some embodiments of the present application.

[0065] In the accompanying drawings, the drawings are not necessarily drawn to scale.

[0066] The accompanying drawings are numbered as follows: 1. vehicle; 2. battery; 3. controller; 4. motor; 5. housing; 5a. first housing portion; 5b. second housing portion; 5c. accommodating space; 6. battery cell; 7. current collector; 10. electrode assembly; 11. main body; 12. first electrode tab; 121. first portion; 122. bending portion; 123. second portion; 124. gathering portion; 13. second electrode tab; 14. first electrode sheet; 141. first current collector; 142. first active material layer; 15. second electrode sheet; 151. second current collector; 152. second active material layer; 16. separator; 20. housing; 21. first housing wall; 211. pressure relief mechanism; 212. injection hole; 213. first outer surface; 22. Second shell wall; 221, second outer surface; 23, first recess; 231, bottom wall; 232, side wall; 24, second recess; 25, third shell wall; 251, first sub-wall; 252, second sub-wall; 20a, shell; 20b, cover plate; 20c, positioning groove; 30, first electrode lead-out member; 31, first connecting plate; 32, second connecting plate; 33, third connecting plate; 34, first electrode terminal; 35, first terminal plate; 351, first terminal portion; 352, second terminal portion; 40, insulating bracket; 40a, first accommodating recess; 40b, second accommodating recess; 40c, drainage wall; 40d, liquid injection channel; 40e, liquid injection opening; 41, insulating substrate; 42, first limiting plate; 43, second limiting plate; 44, third limiting plate; 45, support block; 50, insulating member; 60, first sealing member; 70. Second sealing member; 80. Second electrode lead-out member; 81. Fourth connecting plate; Z, first direction; X, second direction; Y, third direction. DETAILED DESCRIPTION

[0067] Below, with appropriate reference to the accompanying drawings, the embodiments of the sodium ion battery cell, battery, and electrical device of the present application are described in detail. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0068] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0069] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0070] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0071] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0072] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0073] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0074] In this application, the terms "plurality" and "multiple" refer to two or more.

[0075] Unless otherwise stated, the numerical values ​​of the various parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in the examples of this application. Unless otherwise stated, the test temperature of each parameter is 25°C.

[0076] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0077] A battery cell typically includes an electrode assembly, which includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. For example, the electrode assembly also includes a separator disposed between the positive and negative electrodes. The separator prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0078] Battery cells may include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0079] The battery cells may be prismatic battery cells or battery cells of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells or polygonal battery cells. Polygonal battery cells may be, for example, hexagonal battery cells. Battery cells of other shapes may be cylindrical battery cells.

[0080] The battery cells may be hard-shell battery cells, soft-pack battery cells, or other types of battery cells.

[0081] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0082] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0083] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0084] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the chassis of the vehicle, or part of the box body can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0085] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0086] Battery cells generate heat during charging. This heat accumulates within the cells, causing the temperature to rise, which in turn affects the cell's cycle performance and lifespan. In some embodiments, increasing the large surface area of ​​the battery cells can increase the heat dissipation efficiency of the battery cells, reduce the temperature rise of the battery cells during charging and discharging, and improve the cycle performance and lifespan of the battery cells. Assuming the capacity of the battery cells remains constant, the large surface area of ​​the battery cells is negatively correlated with the thickness of the battery cells. Increasing the large surface area of ​​the battery cells may reduce their structural strength, increase the risk of deformation during transportation and use, and affect their reliability.

[0087] In view of this, an embodiment of the present application provides a technical solution, which increases the heat dissipation area of ​​the battery cell by designing the external dimensions of the battery cell, reduces the temperature rise of the battery cell during the charging and discharging process, improves the cycle performance and cycle life of the battery cell, and reduces the risk of deformation of the battery cell due to reduced structural strength, thereby improving the reliability of the battery cell.

[0088] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0089] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0090] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0091] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0092] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may serve as an operating power source for the vehicle 1.

[0093] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0094] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0095] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application.

[0096] As shown in FIG. 2 , the battery 2 includes a case 5 and battery cells 6 (not shown). The battery cells 6 are accommodated in the case 5 .

[0097] The housing 5 is used to accommodate the battery cells 6 and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other and together define a storage space 5c for accommodating the battery cells 6. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0098] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0099] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0100] In the battery 2, there can be one or more battery cells 6. If there are multiple battery cells 6, the multiple battery cells 6 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections within the multiple battery cells 6. The multiple battery cells 6 can be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 6 can be housed within the housing 5. Alternatively, multiple battery cells 6 can be first connected in series, in parallel, or in a hybrid connection to form a battery module, and then the multiple battery modules can be connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 5.

[0101] FIG3 is a schematic structural diagram of batteries provided in other embodiments of the present application.

[0102] As shown in FIG3 , in some embodiments, the battery 2 includes a plurality of battery cells 6 and a plurality of busbar components 7 . The plurality of busbar components 7 can connect the plurality of battery cells 6 in series, in parallel, or in mixed connection.

[0103] 4 is a schematic diagram of a battery cell provided in some embodiments of the present application; FIG5 is a schematic cross-sectional view taken along the AA direction of FIG4 ; FIG6 is an enlarged schematic diagram of the box in FIG5 ; and FIG7 is a schematic cross-sectional view taken along the BB direction of FIG4 .

[0104] 4 to 6 , an embodiment of the present application provides a battery cell 6 , which includes a housing 20 and an electrode assembly 10 , wherein the electrode assembly 10 is accommodated in the housing 20 .

[0105] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell 6, active ions (e.g., lithium ions) are intercalated and released between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes. The separator can reduce the risk of short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0106] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0107] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0108] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, silver surface treated aluminum or stainless steel, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may 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.).

[0109] As an example, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active material layers may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. 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, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0110] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, a positive electrode active material layer may or may not be provided on the surface of the metal foam. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0111] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0112] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, the metal foil may be silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector may include a polymer base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy, etc.) on a polymer substrate (e.g., a substrate made of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0113] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0114] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0115] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0116] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0117] In some embodiments, the separator includes a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0118] As an example, the primary 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, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0119] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0120] The housing 20 is a hollow structure, and its interior forms a space for accommodating the electrode assembly 10 and the electrolyte. The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a rectangular parallelepiped structure, a rectangular housing can be selected.

[0121] The housing 20 can be made of a variety of materials, for example, metal or plastic. Alternatively, the housing 20 can be made of copper, iron, aluminum, steel, aluminum alloy, etc. For example, the housing 20 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film.

[0122] As an example, the housing 20 includes a shell 20 a and a cover 20 b . The shell 20 a has an opening, and the cover 20 b is used to cover the opening.

[0123] The housing 20 a is a component used to cooperate with the cover plate 20 b to form an internal cavity of the battery cell 6 . The formed internal cavity can be used to accommodate the electrode assembly 10 , electrolyte, and other components.

[0124] The housing 20a and the cover 20b may be separate components. For example, an opening may be provided on the housing 20a, and the cover 20b may be placed over the opening to form an internal cavity of the battery cell 6.

[0125] The housing 20a can have various shapes and sizes, such as a rectangular parallelepiped, a hexagonal prism, etc. Specifically, the shape of the housing 20a can be determined according to the specific shape and size of the electrode assembly 10. The housing 20a can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0126] The shape of the cover plate 20b can be adapted to the shape of the housing 20a to fit the housing 20a. The material of the cover plate 20b can be the same as or different from the material of the housing 20a. Optionally, the cover plate 20b can be made of a material with a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the cover plate 20b is less likely to deform when subjected to compression or collision, thereby providing the battery cell 6 with higher structural strength and improved reliability.

[0127] The cover plate 20b can be connected to the housing 20a by welding, bonding, clamping or other methods.

[0128] FIG8 is a schematic diagram of an electrode assembly of a battery cell provided in some embodiments of the present application; FIG9 is a schematic cross-sectional view taken along the CC direction of FIG8 .

[0129] Referring also to Figures 4 to 9 , in some embodiments, a battery cell 6 includes an electrode assembly 10 and a housing 20, with the electrode assembly 10 housed within the housing 20. The housing 20 includes a first housing wall 21 and a second housing wall 22 disposed opposite each other along a first direction Z. The area of ​​the second outer surface 221 of the second housing wall 22 is less than or equal to the area of ​​the first outer surface 213 of the first housing wall 21. The electrode assembly 10 is housed within the housing 20 and includes a main body 11 and a first electrode tab 12. The main body 11 is located between the first housing wall 21 and the second housing wall 22 in the first direction Z. The first electrode tab 12 extends from at least one end of the main body 11 along a second direction X, where the second direction X intersects the first direction Z.

[0130] The electrode assembly 10 is a component where electrochemical reactions occur in the battery cell 6. The housing 20 may contain one or more electrode assemblies 10. The electrode assembly 10 may be a wound structure, a laminate structure, a wound laminate composite structure, or other structures.

[0131] The shape of the electrode assembly 10 can be cylindrical, flat, or polygonal.

[0132] As an example, the electrode assembly 10 includes a first electrode piece 14 , a second electrode piece 15 and an isolating member 16 . The polarity of the first electrode piece 14 is opposite to that of the second electrode piece 15 . The isolating member 16 is used to insulate and isolate the first electrode piece 14 from the second electrode piece 15 .

[0133] The first electrode sheet 14 includes a first current collector 141 and a first active material layer 142 coated on the surface of the first current collector 141. The second electrode sheet 15 includes a second current collector 151 and a second active material layer 152 coated on the surface of the second current collector 151. The main body 11 includes the portion of the first current collector 141 coated with the first active material layer 142, the portion of the second current collector 151 coated with the second active material layer 152, the first active material layer 142, and the second active material layer 152. The first electrode tab 12 includes the portion of the first current collector 141 not coated with the first active material layer 142.

[0134] One of the first electrode sheet 14 and the second electrode sheet 15 is a positive electrode sheet, and the other is a negative electrode sheet.

[0135] The first electrode tab 12 extends from one end of the main body 11 along the second direction X. Alternatively, there may be two first electrode tabs 12 , which extend from both ends of the main body 11 along the second direction X respectively.

[0136] The first wall 21 is a wall of the housing 20 having a certain thickness, and the second wall 22 is a wall of the housing 20 having a certain thickness. The first wall 21 and the second wall 22 are spaced apart along the first direction Z.

[0137] The first shell wall 21 can be in various shapes, such as circular, rectangular, square or other shapes. The second shell wall 22 can be in various shapes, such as circular, rectangular, square or other shapes.

[0138] The first shell wall 21 can be a flat wall or a curved wall. The second shell wall 22 can be a flat wall or a curved wall.

[0139] The area of ​​the second outer surface 221 of the second shell wall 22 can be equal to the area of ​​the first outer surface 213 of the first shell wall 21. For example, the second shell wall 22 and the first shell wall 21 have the same shape and size. Alternatively, the area of ​​the second outer surface 221 of the second shell wall 22 can also be smaller than the area of ​​the first outer surface 213 of the first shell wall 21.

[0140] In the first direction Z, the main body 11 and the second shell wall 22 overlap. In the first direction Z, the first electrode tab 12 and the second shell wall 22 may overlap or may not overlap.

[0141] In some embodiments, the distance between the first shell wall 21 and the second shell wall 22 along the first direction Z is D1 mm, and the area of ​​the second outer surface 221 of the second shell wall 22 is S mm. 2 , S is 36 to 500 times the square of D1.

[0142] For example, D1 may be the minimum distance between the first shell wall 21 and the second shell wall 22 in the first direction Z.

[0143] The second outer surface 221 of the second shell wall 22 is located on one side of the main body 11 along the first direction Z. Along any direction perpendicular to the first direction Z, the projection of the second outer surface 221 of the second shell wall 22 does not overlap with the projection of the main body 11. Exemplarily, the second outer surface 221 of the second shell wall 22 is perpendicular to the first direction Z.

[0144] The battery cells 6 dissipate heat outward through the first and second casing walls 21, 22. The area S of the second outer surface 221 of the second casing wall 22 is less than or equal to the area of ​​the first outer surface 213 of the first casing wall 21. A larger area S increases the heat exchange area between the second casing wall 22 and the outside, and the heat exchange area between the first casing wall 21 and the outside, respectively, leading to higher heat dissipation efficiency for the battery cells 6.

[0145] The main body 11 is the main source of heat generation inside the battery cell 6. The heat generated by the main body 11 needs to be dissipated outward through the first shell wall 21 and the second shell wall 22. The smaller D1 is, the shorter the heat transfer path between the main body 11 and the first shell wall 21 along the first direction Z and the heat transfer path between the main body 11 and the second shell wall 22 along the first direction Z are, and the higher the heat dissipation efficiency of the battery cell 6 is.

[0146] S and D1 also affect the rigidity and structural strength of the battery cell 6. For example, the larger S is and the smaller D1 is, the more the battery cell 6 approaches a thin-sheet structure. During the production, transportation, and use of the battery cell 6, the battery cell 6 is susceptible to deformation when subjected to external impact, which may cause the electrode sheet of the electrode assembly 10 to crack, affecting the reliability of the battery cell 6.

[0147] In the embodiments of the present application, S is set to 36 to 500 times the square of D1, enabling the battery cell to achieve both good heat dissipation efficiency and good rigidity and structural strength. Specifically, S is set to be greater than or equal to 36 times the square of D1 to improve the heat dissipation efficiency of the battery cell 6, reduce heat accumulation within the battery cell, lower the temperature rise of the battery cell during the charge and discharge process, and improve the cycle performance and cycle life of the battery cell. In the embodiments of the present application, S is set to be less than or equal to 500 times the square of D1 to improve the rigidity and structural strength of the battery cell 6, reduce deformation of the battery cell 6 when the battery cell 6 is subjected to external impact, and improve the reliability of the battery cell 6.

[0148] In some embodiments, S may be D1 2 36, 40, 45, 50, 60, 70, 80, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450 or 500 times, or S and D1 2 The ratio of can be within the numerical range formed by any two of the above values.

[0149] In some embodiments, S / D1 2 The range of 45-175 can further balance the cycle performance and reliability performance of the battery cell 6, reduce the temperature rise of the battery cell 6, and reduce the risk of deformation of the battery cell 6.

[0150] In some embodiments, the second outer surface 221 of the second shell wall 22 is a plane.

[0151] In some embodiments, the first outer surface 213 of the first shell wall 21 is planar.

[0152] In some embodiments, the first shell wall 21 and the second shell wall 22 may be used to exchange heat with a heat exchange plate of a battery.

[0153] In some embodiments, the second shell wall 22 has a dimension D2 mm along the second direction X and a dimension D3 mm along the third direction Y. The first direction Z, the second direction X, and the third direction Y are perpendicular to each other. D1, D2, and D3 satisfy: D2>D3>D1.

[0154] Exemplarily, D2 is the minimum dimension of the second shell wall 22 along the second direction X, and D3 is the minimum dimension of the second shell wall 22 along the third direction Y.

[0155] It can be understood that “vertical” includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering.

[0156] The main body 11 may be the primary factor determining the capacity of the battery cell 6. D2 is related to the size of the main body 11 along the second direction X, and D3 is related to the size of the main body 11 along the third direction Y. The first tab 12 extends from the end of the main body 11 along the second direction X. It will occupy additional space in the second direction X but will not occupy additional space in the third direction Y. This embodiment of the present application can make the main body 11 have a larger size along the second direction X, thereby reducing the ratio of the size of the first tab 12 along the second direction X to the size of the main body 11 along the second direction X, improving space utilization, and increasing the energy density of the battery cell 6. D1 is smaller than D2 and D3, which can shorten the heat transfer path, improve heat dissipation efficiency, and improve the cycle performance and cycle life of the battery cell.

[0157] In some embodiments, the second housing wall 22 is rectangular, where S = D2 x D3. It is understood that "rectangular" includes not only a standard rectangle but also what is generally considered a rectangle. For example, if the four corners of the second housing wall 22 are rounded, the second housing wall 22 can also be considered a rectangle.

[0158] In some embodiments, D2 / D3 is 4-10.2.

[0159] When D2×D3 is constant, the larger D2 is, the higher the utilization rate of the main body 11 in the second direction X is; the larger D3 is, the larger the size of the first electrode tab 12 along the third direction Y is, and the stronger the current carrying capacity of the first electrode tab 12 is.

[0160] In the embodiment of the present application, D2 / D3 is limited to 4-10.2, which can balance the space utilization of the battery cell 6 and the flow capacity of the first electrode 12, thereby improving the space utilization and increasing the energy density of the battery cell 6 while the flow capacity of the first electrode 12 meets the requirements.

[0161] Optionally, D2 / D3 is 4, 5, 6, 7, 8, 9, 9.5, 10 or 10.2.

[0162] In some embodiments, D2 / D3 is 5-7 to further balance the space utilization of the battery cell 6 and the current capacity of the first tab 12 .

[0163] In some embodiments, D3 / D1 is 3-7, which can improve the heat dissipation efficiency of the battery cell 6, reduce the temperature rise of the battery cell during charging and discharging, and improve the stiffness and structural strength of the battery cell 6, reduce the deformation of the battery cell 6 when the battery cell 6 is subjected to external impact, and improve the reliability of the battery cell 6.

[0164] Optionally, D3 / D1 is 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7.

[0165] In some embodiments, D3 / D1 is 3-5, which can further improve the heat dissipation efficiency of the battery cell 6, reduce the temperature rise of the battery cell during charging and discharging, and improve the stiffness and structural strength of the battery cell 6, reduce the deformation of the battery cell 6 when the battery cell 6 is subjected to external impact, and improve the reliability of the battery cell 6.

[0166] In some embodiments, D2 is 300-3000. Alternatively, D2 is 300, 400, 500, 600, 1000, 1200, 1500, 2000, 2500 or 3000.

[0167] In the embodiment of the present application, D2 is greater than or equal to 300, which allows the battery cell 6 to have a larger size in the second direction X, thereby reducing the number of battery cells 6 in the battery, simplifying the battery molding process, and improving the battery's energy density. D2 is less than or equal to 3000, which can reduce the difference in the conductive path between the two ends of the main body 11 and the first terminal 12, thereby reducing heat generation.

[0168] In some embodiments, D2 is 500-1000.

[0169] In some embodiments, the energy of the battery cell 6 is 150×D1×S×10 -6 -600×D1×S×10 -6 , the unit of energy is Wh.

[0170] The energy of the battery cell 6 is related to the heat generated by the battery cell 6. The embodiment of the present application limits the energy of the battery cell 6 according to D1×S, which can, to a certain extent, achieve a certain balance between the heat dissipation efficiency of the battery cell 6 and the heat generated by the battery cell 6, reduce the temperature rise of the battery cell during the charging and discharging process, and improve the cycle performance of the battery cell 6.

[0171] Optionally, the energy of the battery cell is 150×D1×S×10 -6 Wh, 150×D1×S×10 -6 Wh, 200×D1×S×10 -6 Wh, 300×D1×S×10 -6 Wh, 400×D1×S×10 -6 Wh, 500×D1×S×10 -6 Wh or 600×D1×S×10 -6 Wh.

[0172] For example, taking a lithium iron phosphate battery cell as an example, the energy of the battery cell can be measured as follows:

[0173] Fully charge the battery at 1 / 3 of its capacity, until the voltage is 3.7V. Then discharge the battery at 1 / 3 of its capacity until it reaches 2.5V, and measure the discharge capacity. Energy = discharge capacity x voltage plateau (3.2V).

[0174] In some embodiments, the thickness of the second shell wall 22 is 0.1 mm-0.8 mm to balance the strength and weight of the second shell wall 22 , improve the reliability of the battery cell 6 , and increase the energy density of the battery cell 6 .

[0175] Optionally, the thickness of the second shell wall 22 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm or 0.8 mm.

[0176] In some embodiments, the thickness of the second shell wall 22 is 0.2 mm-0.5 mm to balance the strength and weight of the second shell wall 22 , improve the reliability of the battery cell 6 , and increase the energy density of the battery cell 6 .

[0177] In some embodiments, the thickness of the second shell wall 22 is 0.3 mm.

[0178] In some embodiments, the area of ​​the second outer surface 221 of the second shell wall 22 is smaller than the area of ​​the first outer surface 213 of the first shell wall 21. A first recess 23 is defined at an end of the housing 20 along the second direction X. The first recess 23 is recessed from the second shell wall 22 toward the first shell wall 21. In the first direction Z, at least a portion of the first tab 12 is located between a bottom wall 231 of the first recess 23 and the first shell wall 21.

[0179] The first recess 23 is recessed relative to the second outer surface 221 of the second shell wall 22 .

[0180] In the embodiment of the present application, the first electrode tab 12 requires less space in the first direction Z. Therefore, a first recess 23 can be provided on the outer side of the housing 20 to reduce the volume of the battery cell 6 and improve the volume energy density of the battery cell 6 .

[0181] Exemplarily, the first outer surface 213 is parallel to the second outer surface 221 .

[0182] In some embodiments, the housing 20 includes two third shell walls 25 disposed opposite each other along a third direction Y. Each third shell wall 25 is connected to the first shell wall 21 and the second shell wall 22. The first direction Z, the second direction X, and the third direction Y are perpendicular to each other. In the third direction Y, at least a portion of the first electrode tab 12 is located between the two third shell walls 25. In the third direction Y, the first electrode tab 12 has a dimension of L1 mm, the spacing between the two third shell walls 25 is L2 mm, and the ratio L1 / L2 is 0.2-0.9.

[0183] In the embodiment of the present application, L1 / L2 is limited to be greater than or equal to 0.2 to increase the flow capacity of the first electrode tab 12 and reduce the heat generation of the first electrode tab 12. In the embodiment of the present application, L1 / L2 is limited to be less than or equal to 0.9 to reduce the risk of short circuit between the first electrode tab 12 and the third shell wall 25.

[0184] Optionally, L1 / L2 is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9.

[0185] In some embodiments, L1 / L2 is 0.5-0.8, so as to further increase the current carrying capacity of the first electrode tab 12 and reduce the risk of short circuit between the first electrode tab 12 and the third shell wall 25 .

[0186] In some embodiments, the side wall 232 of the first recess 23 is connected to the second shell wall 22 .

[0187] In some embodiments, the first recess 23 passes through the housing 20 along the third direction Y.

[0188] In some embodiments, the third housing wall 25 is a special-shaped wall. For example, the third housing wall 25 includes a first sub-wall 251 and a second sub-wall 252 arranged along the second direction X. The first sub-wall 251 is connected to the first housing wall 21, the second housing wall 22, and the side wall 232 of the first recess 23. The second sub-wall 252 extends from one end of the first sub-wall 251 along the second direction X and connects the bottom wall 231 of the first recess 23 and the first housing wall 21.

[0189] In some embodiments, in the third direction Y, the main body 11 is located between the two first sub-walls 251 , and at least a portion of the first electrode tab 12 is located between the two second sub-walls 252 .

[0190] In some embodiments, the electrode assembly 10 further includes a second electrode tab 13 , and the first electrode tab 12 and the second electrode tab 13 have opposite polarities. Exemplarily, the second electrode tab 13 includes a portion of the second current collector 151 that is not coated with the second active material layer 152 .

[0191] The second electrode tab 13 and the first electrode tab 12 may extend from the same end of the main body 11 along the second direction X, or may extend from two ends of the main body 11 along the second direction X respectively.

[0192] In some embodiments, the first electrode tab 12 and the second electrode tab 13 extend from both ends of the main body 11 along the second direction X, respectively, to reduce the risk of short circuit caused by contact between the first electrode tab 12 and the second electrode tab 13 .

[0193] In some embodiments, L1 / L2 is 0.5-0.8. Alternatively, L1 / L2 is 0.5, 0.6, 0.7 or 0.8.

[0194] The first electrode tab 12 and the second electrode tab 13 extend from both ends of the main body 11 along the second direction X, respectively, and the two can share space in the third direction Y. Therefore, the first electrode tab 12 can have a larger size in the third direction Y, thereby improving the current flow capacity of the first electrode tab 12 and reducing the temperature rise of the first electrode tab 12.

[0195] In some embodiments, in the third direction Y, the size of the main body 11 is L3 mm, and L3 / L2 is 0.9-0.99. Optionally, L3 / L2 is 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98 or 0.99.

[0196] The embodiment of the present application can improve the space utilization of the main body 11 in the third direction Y and reduce the difficulty of installing the main body 11 between the two third shell walls 25.

[0197] In some embodiments, L3 / L2 is 0.95-0.98.

[0198] In some embodiments, the battery cell 6 further includes a first electrode lead-out member 30 . The first electrode lead-out member 30 is disposed on the first shell wall 21 and electrically connected to the first electrode tab 12 .

[0199] For example, the first electrode lead-out member 30 may be used to electrically connect the electrode assembly 10 to the current outside the battery cell, thereby enabling charging and discharging of the battery cell.

[0200] In some embodiments, at least a portion of the first electrode lead-out member 30 is located outside the first casing wall 21. The portion of the first electrode lead-out member 30 located outside the first casing wall 21 can be used to electrically connect to other components, such as a busbar of a battery.

[0201] In some embodiments, in the first direction Z, a projection of a portion of the first electrode lead-out member 30 located outside the first casing wall 21 is at least partially located within a projection of the first recess 23 .

[0202] When multiple battery cells 6 are arranged along the first direction Z, the first recess 23 of one battery cell 6 can avoid the first electrode lead 30 (or the second electrode lead described later) of another battery cell 6, thereby improving space utilization and enhancing battery energy density.

[0203] In some embodiments, in the first direction Z, the projection of the portion of the first electrode lead-out member 30 located outside the first casing wall 21 is entirely located within the projection of the first recess 23 .

[0204] In some embodiments, the first electrode lead 30 includes a first connecting plate 31 housed within the housing 20. At least a portion of the first electrode tab 12 is stacked and connected to the first connecting plate 31 in a first direction Z. In a third direction Y, the first electrode tab 12 has a dimension of L1 mm, the first connecting plate 31 has a dimension of L4 mm, and L1 / L4 is 0.6-1. The first direction Z, the second direction X, and the third direction Y are perpendicular to each other.

[0205] In this embodiment of the present application, L1 / L4 is limited to greater than or equal to 0.6 to increase the connection area between the first electrode tab 12 and the first connecting plate 31, improve the flow capacity between the first electrode tab 12 and the first connecting plate 31, and reduce temperature rise. In this embodiment of the present application, L1 / L4 is limited to less than or equal to 1 to reduce the space wasted by the first electrode tab 12 and improve space utilization.

[0206] In some embodiments, L1 / L4 is 0.8-0.9. Limiting L1 / L4 to be less than or equal to 0.9 reduces the risk of the first tab 12 protruding from the first connecting plate 31 in the third direction Y due to assembly error, thereby reducing space waste.

[0207] In some embodiments, the first tab 12 is welded to the first connecting plate 31 .

[0208] In some embodiments, at least a portion of the first electrode tab 12 is located on a side of the first connecting plate 31 facing away from the first shell wall 21 and is connected to the first connecting plate 31 .

[0209] In some embodiments, the first connecting plate 31 is located on one side of the main body 11 along the second direction X.

[0210] In some embodiments, the first electrode tab 12 includes a first portion 121, a bent portion 122, and a second portion 123. The first portion 121 is connected to the main body 11, is located on the side of the first connecting plate 31 away from the first shell wall 21, and is connected to the first connecting plate 31. The bent portion 122 extends from one end of the first portion 121 away from the main body 11 and is bent relative to the first portion 121. The second portion 123 extends from one end of the bent portion 122 away from the first portion 121 toward the main body 11.

[0211] The first electrode tab 12 may be folded back at the end of the first connecting plate 31 away from the main body 11 , which may reduce the space occupied by the first electrode tab 12 in the second direction X and improve space utilization.

[0212] In some embodiments, the first tab 12 further includes a gathering portion 124 , which is connected between the first portion 121 and the main body 11 .

[0213] Exemplarily, the first tab 12 includes a plurality of stacked conductive layers, which are gathered and stacked on the first connection plate 31 and then welded to the first connection plate 31. The roots of the plurality of conductive layers are gathered to form a gathered portion 124.

[0214] In some embodiments, the first electrode lead-out member 30 further includes a second connecting plate 32 , which extends from an end of the first connecting plate 31 close to the main body 11 toward the first shell wall 21 .

[0215] For example, the second connecting plate 32 can separate the main body 11 from the second portion 123 in the second direction X to reduce the risk of the first electrode tab 12 being inserted into the main body 11 and improve the reliability of the battery cell 6 .

[0216] In some embodiments, the first electrode lead-out member 30 further includes a third connecting plate 33 . The third connecting plate 33 is connected to an end of the second connecting plate 32 away from the first connecting plate 31 and is located between the first shell wall 21 and the first connecting plate 31 .

[0217] Exemplarily, the third connecting plate 33 , the second connecting plate 32 and the second connecting plate 32 enclose an accommodation space to accommodate the second portion 123 , thereby reducing the risk of the second portion 123 contacting the housing 20 .

[0218] In some embodiments, the third connecting plate 33 , the second connecting plate 32 and the second connecting plate 32 form an integrated C-shaped structure.

[0219] In some embodiments, the first electrode lead-out member 30 further includes a first electrode terminal 34 , which is connected to the third connection plate 33 and passes through the first housing wall 21 .

[0220] There may be one or more first electrode terminals 34 .

[0221] The first electrode terminal 34 and the third connecting plate 33 may be integrally formed, or may be connected to the third connecting plate 33 by welding, riveting or other methods.

[0222] The first electrode terminal 34 passes through the first housing wall 21 to lead current to the outside of the battery cell 6 .

[0223] In some embodiments, the first electrode lead-out member 30 further includes a first terminal plate 35 . The first terminal plate 35 is located on a side of the first shell wall 21 away from the first electrode tab 12 and is connected to the first electrode terminal 34 .

[0224] The first terminal plate 35 is provided to facilitate electrical connection with an external conductive structure, thereby improving the current carrying capacity.

[0225] For example, the first terminal plate 35 can be used to connect with the busbar component. Optionally, the first terminal plate 35 and the busbar component are arranged along the second direction X and connected.

[0226] In some embodiments, the projection of the first terminal plate 35 is located within the projection of the first recess 23 in the first direction Z. When multiple battery cells 6 are arranged along the first direction Z, the first recess 23 of one battery cell 6 can avoid the first terminal plate 35 of another battery cell 6, thereby improving space utilization and increasing the energy density of the battery.

[0227] In some embodiments, the first terminal plate 35 includes a first terminal portion 351 and a second terminal portion 352 . The first terminal portion 351 is connected to the first electrode terminal 34 , and the second terminal portion 352 is protruded from a surface of the first terminal portion 351 facing away from the first housing wall 21 .

[0228] Both the first terminal portion 351 and the second terminal portion 352 can be used to connect to the busbar component. By providing the second terminal portion 352, the connection area between the first terminal plate 35 and the busbar component can be increased.

[0229] In some embodiments, an end surface of the first terminal portion 351 facing the busbar along the second direction X is flush with an end surface of the second terminal portion 352 facing the busbar along the second direction X.

[0230] In some embodiments, the first connecting plate 31 , the second connecting plate 32 , the third connecting plate 33 and the first electrode terminal 34 are an integrally formed structure.

[0231] In some embodiments, the first electrode terminal 34 is riveted to the first terminal plate 35 . For example, the first electrode terminal 34 is riveted to the first terminal portion 351 .

[0232] In some embodiments, the battery cell 6 further includes an insulating bracket 40 accommodated in the housing 20 and disposed with the main body 11 along the second direction X. A first receiving recess 40 a is disposed on a side of the insulating bracket 40 facing the main body 11 .

[0233] In some embodiments, at least a portion of the first electrode tab 12 is received in the first receiving recess 40 a .

[0234] The insulating support 40 can accommodate the first tab 12 and isolate at least a portion of the first tab 12 from the housing 20 to reduce the risk of short circuit. The first receiving recess 40a can also gather the first tab 12 to reduce the risk of the first tab 12 spreading out.

[0235] In some embodiments, at least a portion of the first electrode tab 12 extends into the first accommodating recess 40 a and is bent within the first accommodating recess 40 a.

[0236] The wall of the first accommodating recess 40 a can guide the first electrode tab 12 to bend, thereby reducing the space occupied by the first electrode tab 12 in the second direction X and lowering the risk of the first electrode tab 12 contacting the housing 20 during the bending process, thereby improving reliability.

[0237] In some embodiments, in the second direction X, the first connecting plate 31 is located between the insulating bracket 40 and the main body 11, and the end of the first connecting plate 31 away from the main body 11 extends into the first accommodating recess 40a. The first tab 12 is bent within the first accommodating recess 40a along the end of the first connecting plate 31 away from the main body 11.

[0238] The wall of the first accommodating recess 40 a can guide the first electrode tab 12 to bend along the end of the first connecting plate 31 away from the main body 11 , so as to reduce the space occupied by the first electrode tab 12 in the second direction X.

[0239] In some embodiments, the bent portion 122 is received in the first receiving recess 40 a.

[0240] In some embodiments, in the first direction Z, a portion of the insulating support 40 is located between the first electrode lead-out member 30 and the first casing wall 21 .

[0241] The first electrode lead-out member 30 and the first shell wall 21 can limit the insulating bracket 40 in the first direction Z, thereby reducing the risk of the insulating bracket 40 shaking in the shell 20 when the battery cell 6 is subjected to external impact.

[0242] In some embodiments, the insulating bracket 40 includes an insulating base plate 41, a first limiting plate 42, and a second limiting plate 43. The insulating base plate 41 is spaced apart from the main body 11 along the second direction X. The first limiting plate 42 and the second limiting plate 43 are located on the side of the insulating base plate 41 facing the main body 11 and are spaced apart along the first direction Z, which is perpendicular to the first direction Z. The first accommodating recess 40a is located between the first limiting plate 42 and the second limiting plate 43. In the first direction Z, the bent portion 122 is located between the first limiting plate 42 and the second limiting plate 43. The second portion 123 is located on the side of the first portion 121 that is closest to the second limiting plate 43.

[0243] The first limiting plate 42 and the second limiting plate 43 can limit and insulate the first electrode tab 12 , thereby reducing the risk of conduction between the first electrode tab 12 and the housing 20 and improving reliability.

[0244] In some embodiments, at least a portion of the first limiting plate 42 is located between the first portion 121 and the bottom wall 231 of the first recess 23 to insulate the first portion 121 from the bottom wall 231 .

[0245] In some embodiments, the second limiting plate 43 is located on a side of the first limiting plate 42 facing the first shell wall 21 .

[0246] In some embodiments, the thickness of the second limiting plate 43 is greater than that of the first limiting plate 42. The second limiting plate 43 supports the second portion 123 and needs to withstand the stress generated by bending the first electrode tab 12. Therefore, the second limiting plate 43 can be thicker than the first limiting plate 42 to provide effective support for the first electrode tab 12 and reduce the risk of deformation of the second limiting plate 43. The first limiting plate primarily serves as an insulator and can be thinner than the second limiting plate 43 to reduce the weight of the insulating bracket 40.

[0247] In some embodiments, in the second direction X, an end of the first limiting plate 42 facing the main body 11 extends beyond an end of the second limiting plate 43 facing the main body 11, thereby insulating the first portion 121 from the housing 20. The second limiting plate 43 may have a smaller dimension than the first limiting plate 42 in the second direction X to reduce the weight of the insulating bracket 40.

[0248] In some embodiments, a portion of the insulating bracket 40 is located between the third connecting plate 33 and the first shell wall 21 .

[0249] The third connecting plate 33 and the first shell wall 21 can limit the insulating bracket 40 in the first direction Z, thereby reducing the risk of the insulating bracket 40 shaking in the shell 20 when the battery cell 6 is subjected to external impact.

[0250] In some embodiments, the insulating bracket 40 is fixed to the first shell wall 21 .

[0251] In some embodiments, the first electrode lead-out member 30 fixes the insulating bracket 40 to the first shell wall 21 .

[0252] In some embodiments, the insulating bracket 40 further includes a third limiting plate 44, which is located on a side of the second limiting plate 43 facing the first housing wall 21 and is connected to the insulating base plate 41. In the first direction Z, at least a portion of the third connecting plate 33 is located between the second limiting plate 43 and the third limiting plate 44, and at least a portion of the third limiting plate 44 is located between the first housing wall 21 and the third connecting plate 33.

[0253] The third limiting plate 44 is provided so that the first shell wall 21 and the third connecting plate 33 can limit the insulating bracket 40. The third connecting plate 33 can utilize the space between the second limiting plate 43 and the third limiting plate 44, thereby improving space utilization.

[0254] Illustratively, the third limiting plate 44 , the second limiting plate 43 and the insulating substrate 41 enclose a second accommodating recess 40 b , and at least a portion of the third connecting plate 33 is disposed in the second accommodating recess 40 b .

[0255] In some embodiments, the battery cell 6 further includes an insulating member 50 , which is used to insulate and isolate the first electrode lead-out member 30 from the first shell wall 21 .

[0256] In some embodiments, at least a portion of the insulating member 50 is located between the first housing wall 21 and the third connecting plate 33. The third limiting plate 44 is connected to the insulating member 50.

[0257] In some embodiments, a second recess 24 is provided at an end of the housing 20 along the second direction X. The second recess 24 is recessed relative to a surface of the second housing wall 22 facing away from the first housing wall 21. The first recess 23 and the second recess 24 are respectively located on both sides of the second housing wall 22 along the second direction X.

[0258] In some embodiments, in the first direction Z, at least a portion of the second electrode tab 13 is located between the bottom wall of the second recess 24 and the first shell wall 21 .

[0259] In some embodiments, the battery cell 6 further includes a second electrode lead-out member 80 . The second electrode lead-out member 80 is disposed on the first shell wall 21 and electrically connected to the second electrode tab 13 .

[0260] In some embodiments, at least a portion of the second electrode lead-out member 80 is located outside the first casing wall 21 .

[0261] In some embodiments, in the first direction Z, a projection of a portion of the second electrode lead-out member 80 located outside the first casing wall 21 is located within a projection of the second recess 24 .

[0262] For example, when two battery cells 6 are arranged along the first direction Z and need to be connected in parallel, the first recess 23 of one battery cell 6 can avoid the first electrode lead-out piece 30 of the other battery cell 6 , and the second recess 24 of the one battery cell 6 can avoid the second electrode lead-out piece 80 of the other battery cell 6 .

[0263] When two battery cells 6 are arranged along the first direction Z and need to be connected in series, the first recess 23 of one battery cell 6 can avoid the second electrode lead-out piece 80 of the other battery cell 6 , and the second recess 24 of the one battery cell 6 can avoid the first electrode lead-out piece 30 of the other battery cell 6 .

[0264] In some embodiments, the second electrode lead-out member 80 includes a fourth connecting plate 81 accommodated in the housing 20 , and at least a portion of the second electrode tab 13 is stacked and connected to the fourth connecting plate 81 in the first direction Z.

[0265] In some embodiments, the fourth connecting plate 81 is made of copper, and the first connecting plate 31 is made of aluminum. The ratio of the thickness of the fourth connecting plate 81 to the thickness of the first connecting plate 31 is 0.4-1. Copper has a higher current carrying capacity than aluminum. This embodiment of the present application can reduce the amount of copper used while still meeting the required current carrying capacity, thus saving costs.

[0266] In some embodiments, the AC internal resistance of the battery cell 6 is less than or equal to 1 milliohm.

[0267] For example, the internal resistance of the battery cell 6 can be measured as follows: an AC current signal with a frequency of 1.0 kHz and an effective value of Ia is applied to the battery cell 6 for 5 seconds, and the AC effective voltage Ua is measured. The AC internal resistance Rac is Ua / Ia.

[0268] The AC internal resistance of the battery cell 6 is relatively small, which can reduce the heat generation of the battery cell 6 and improve the cycle performance of the battery cell.

[0269] In some embodiments, the second shell wall 22 is made of aluminum or steel. Aluminum and steel have high strength and good thermal conductivity. Using aluminum or steel second shell wall 22 can improve the cycle performance of the battery cell and enhance the reliability of the battery cell.

[0270] In some embodiments, the first shell wall 21 is made of aluminum or steel. Aluminum and steel have high strength and good thermal conductivity. Using aluminum or steel first shell wall 21 can improve the cycle performance of the battery cell and enhance the reliability of the battery cell.

[0271] In some embodiments, the electrode assembly is a laminate structure.

[0272] In some embodiments, the electrode assembly 10 includes multiple first pole pieces 14 and multiple second pole pieces 15 , the polarity of the first pole pieces 14 is opposite to the polarity of the second pole pieces 15 , and the multiple first pole pieces 14 and the multiple second pole pieces 15 are alternately stacked along the first direction Z.

[0273] The electrode assembly 10 adopts a laminated structure, which can improve space utilization and increase the energy density of the battery cell.

[0274] In some embodiments, the housing 20 includes a shell 20 a and a cover 20 b arranged along a first direction Z. The shell 20 a has an opening, and the cover 20 b covers the opening. The shell 20 a includes a second shell wall 22 , and the cover 20 b includes a first shell wall 21 .

[0275] The housing 20a and the cover plate 20b can be covered with each other to form a receiving space for receiving the electrode assembly. The housing 20a and the cover plate 20b are easy to form and assemble.

[0276] In some embodiments, the housing 20 a includes two third walls 25 .

[0277] In some embodiments, the first recess 23 and the second recess 24 are provided on the housing 20 a.

[0278] In some embodiments, the housing 20a is welded to the cover plate 20b.

[0279] FIG10 is a schematic diagram of a battery cell provided in some embodiments of the present application; FIG11 is a schematic diagram of a partial cross-section of a battery cell at a liquid injection hole provided in some embodiments of the present application.

[0280] As shown in Figures 10 and 11 , in some embodiments, the dimension of the first shell wall 21 along the second direction X is D4 mm, and the dimension of the first shell wall 21 along the third direction Y is D5 mm. D4>D5>D1.

[0281] In some embodiments, the first shell wall 21 is rectangular. It is understood that "rectangular" includes not only a standard rectangle but also a generally rectangular shape. For example, after the four corners of the first shell wall 21 are rounded, the first shell wall 21 can also be considered a rectangle.

[0282] In some embodiments, the area of ​​the first outer surface 213 of the first shell wall 21 is D4×D5.

[0283] In some embodiments, the first shell wall 21 is provided with a pressure relief mechanism 211 .

[0284] There can be one or more pressure relief mechanisms 211 .

[0285] The pressure relief mechanism 211 significantly impacts the reliability of the battery cells. For example, short circuits, overcharging, and other conditions can cause thermal runaway within the battery cells, leading to a sudden increase in pressure. In these situations, the pressure relief mechanism 211 is activated to release the internal pressure, preventing explosion or fire.

[0286] The pressure relief mechanism 211 is a component or element that activates to release the internal pressure of a battery cell when the internal pressure reaches a predetermined threshold. This threshold varies depending on the design requirements. It may depend on the materials of one or more of the positive electrode plate, negative electrode plate, electrolyte, and separator in the battery cell.

[0287] In some examples, the first shell wall 21 and the pressure relief mechanism 211 may be integrally formed. In alternative examples, the pressure relief mechanism 211 and the first shell wall 21 are independently formed components that may be connected by welding, bonding, or other means. For example, the first shell wall 21 may be provided with a pressure relief hole that extends through the first shell wall 21. The pressure relief mechanism 211 may be mounted on the first shell wall 21 and cover the pressure relief hole, thereby separating the space inside and outside the first shell wall 21.

[0288] In some embodiments, the first shell wall 21 and the pressure relief mechanism 211 are formed integrally, and the pressure relief mechanism 211 includes a weak portion.

[0289] The strength of the weak portion is lower than that of other portions of the first shell wall 21 , and the weak portion is a portion that is easily broken, shattered, torn, or opened.

[0290] In some examples, grooves, notches, or other structures may be provided in a predetermined region of the first shell wall 21 to reduce the local strength of the first shell wall 21, thereby forming a weak portion in the first shell wall 21. For example, a predetermined region of the first shell wall 21 may be thinned, and the thinned portion of the first shell wall 21 may form the weak portion. In other examples, a material treatment may be performed on the predetermined region of the first shell wall 21 to make the strength of the region weaker than that of other regions. In other words, the region may serve as the weak portion.

[0291] The first shell wall 21 and the pressure relief mechanism 211 are formed integrally, which not only saves the process of connecting the first shell wall 21 and the pressure relief mechanism 211 , but also improves the connection strength between the first shell wall 21 and the pressure relief mechanism 211 .

[0292] In some embodiments, the pressure relief mechanism 211 does not overlap with the main body 11 in the first direction Z. This embodiment of the present application can reduce the risk of the main body 11 blocking the pressure relief mechanism 211 when thermal runaway occurs in the battery cell 6, thereby releasing pressure in a timely manner and improving the reliability of the battery cell 6.

[0293] In some embodiments, the minimum distance H1 between the pressure relief mechanism 211 and the edge of the first shell wall 21 is 2 mm to 5 mm. Optionally, H1 is 2 mm, 3 mm, 4 mm, or 5 mm.

[0294] In this embodiment of the present application, H1 is set to be greater than or equal to 2 mm to reduce the force on the pressure relief mechanism 211 when the edge of the first shell wall 21 is impacted, thereby reducing the risk of the pressure relief mechanism 211 rupturing or failing, and improving reliability. H1 is set to be less than or equal to 5 mm to reduce the risk of the pressure relief mechanism 211 being blocked by the main body 11.

[0295] In some embodiments, the first shell wall 21 is provided with a liquid injection hole 212. During the production process of the battery cell, electrolyte can be injected into the shell 20 through the liquid injection hole 212.

[0296] There can be one or more liquid injection holes 212 .

[0297] In some embodiments, the minimum distance H2 between the pressure relief mechanism 211 and the liquid injection hole 212 is greater than or equal to 1 mm.

[0298] During the injection process, the area around the injection hole 212 will be squeezed by the injection equipment and impacted by the electrolyte. The embodiment of the present application can reduce the stress transmitted to the pressure relief mechanism 211, reduce the risk of rupture and failure of the pressure relief mechanism 211, and improve reliability.

[0299] In some embodiments, the battery cell 6 includes a first sealing member 60 . The first sealing member 60 is connected to the first shell wall 21 and covers the injection hole 212 from the outside to seal the injection hole 212 .

[0300] Exemplarily, the first sealing member 60 is welded to the first housing wall 21 .

[0301] In some embodiments, the battery cell 6 includes a second sealing member 70 , which is inserted into the liquid injection hole 212 and has an interference fit with the liquid injection hole 212 .

[0302] Exemplarily, the second sealing member 70 includes a rubber stud.

[0303] Figure 12 is a structural schematic diagram of an insulating bracket provided in some embodiments of the present application; Figure 13 is a structural schematic diagram of the insulating bracket of Figure 12 from another perspective; and Figure 14 is a cross-sectional schematic diagram of Figure 13 taken along the EE direction.

[0304] 11 to 14 , in some embodiments, the insulating bracket 40 is provided with an injection channel 40d, which communicates with the space between the main body 11 and the insulating bracket 40. The peripheral wall of the injection channel 40d includes a drainage wall 40c. The injection hole 212 is axially opposed to the drainage wall 40c, and the injection channel 40d is located on the side of the drainage wall 40c facing the injection hole 212.

[0305] The drainage wall 40 c of the insulating bracket 40 can withstand the impact of the electrolyte and guide the electrolyte to flow in the injection channel 40 d , thereby reducing the impact of the electrolyte on the main body 11 and reducing the deformation of the separator.

[0306] In some embodiments, the injection channel 40d forms an injection opening 40e on the surface of the insulating bracket 40 facing the main body 11. The electrolyte can flow out through the injection opening 40e and infiltrate the main body 11.

[0307] In some embodiments, the insulating bracket 40 includes two support blocks 45 . In the third direction, the first limiting plate 42 , the second limiting plate 43 and the third limiting plate 44 are disposed between the two support blocks 45 and connected to the two support blocks 45 .

[0308] In some embodiments, the injection channel 40 d is disposed on the support block 45 .

[0309] FIG15 is a schematic cross-sectional view of a cover plate of a battery cell provided in some embodiments of the present application.

[0310] As shown in FIG8 and FIG15 , a positioning groove 20 c is provided on the surface of the cover 20 b facing the housing 20 a , and a portion of the main body 11 is accommodated in the positioning groove 20 c .

[0311] During assembly, the positioning groove 20c can position the main body 11 to improve assembly efficiency.

[0312] For example, the positioning groove 20 c can improve the positioning accuracy of the first electrode tab 12 and the first connecting plate 31 and reduce the risk of cold welding by positioning the main body 11 .

[0313] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of battery cells according to any of the above embodiments.

[0314] According to some embodiments of the present application, the present application further provides an electrical device comprising a battery cell according to any of the above embodiments, the battery cell being used to provide electrical energy to the electrical device. The electrical device may be any of the aforementioned devices or systems using the battery cell.

[0315] 4 to 10 , an embodiment of the present application provides a battery cell 6 , which includes an electrode assembly 10 and a housing 20 .

[0316] The housing 20 includes a shell 20a and a cover 20b arranged along a first direction Z. The shell 20a has an opening and the cover 20b covers the opening. The cover 20b includes a first shell wall 21 and the shell 20a includes a second shell wall 22. The first shell wall 21 and the second shell wall 22 are arranged opposite to each other along the first direction Z.

[0317] The housing 20a has a first recess 23 and a second recess 24 at its ends along the second direction X. The first recess 23 is recessed from the second housing wall 22 toward the first housing wall 21, and the second recess 24 is recessed from the second housing wall 22 toward the first housing wall 21. The area of ​​the second outer surface 221 of the second housing wall 22 is smaller than the area of ​​the first outer surface 213 of the first housing wall 21.

[0318] The electrode assembly 10 is housed in the outer shell 20 and includes a main body 11, a first electrode tab 12 and a second electrode tab 13. The first electrode tab 12 and the second electrode tab 13 extend from both ends of the main body 11 along the second direction X respectively. The main body 11 is located between the first shell wall 21 and the second shell wall 22 in the first direction Z. The second direction X is perpendicular to the first direction Z.

[0319] In the first direction Z, at least a portion of the first electrode tab 12 is located between the bottom wall of the first recess 23 and the first shell wall 21 , and at least a portion of the second electrode tab 13 is located between the bottom wall of the second recess 24 and the first shell wall 21 .

[0320] The distance between the first shell wall 21 and the second shell wall 22 along the first direction Z is D1 mm, the dimension of the second shell wall 22 along the second direction X is D2 mm, and the dimension of the second shell wall 22 along the third direction Y is D3 mm. D2 / D3 is 5-7, and D3 / D1 is 3-5.

[0321] According to some embodiments of the present application, a battery cell is provided, comprising a housing, an electrode assembly, and a first electrode lead. The housing comprises a first shell wall and a second shell wall disposed opposite each other along a first direction, wherein the area of ​​the second outer surface of the second shell wall is less than or equal to the area of ​​the first outer surface of the first shell wall. The electrode assembly is housed within the housing and comprises a main body and a first electrode tab, wherein the main body is positioned between the first shell wall and the second shell wall in the first direction, and the first electrode tab extends from at least one end of the main body along a second direction, where the second direction intersects the first direction.

[0322] The first electrode lead-out member is arranged on the first shell wall. The first electrode lead-out member includes a first connecting plate, a second connecting plate, a third connecting plate, a first electrode terminal and a first terminal plate, which is located on the side of the first shell wall away from the first pole ear and is connected to the first electrode terminal. The first connecting plate is accommodated in the shell, and at least a portion of the first pole ear is located on the side of the first connecting plate away from the first shell wall and is connected to the first connecting plate. The second connecting plate extends from an end of the first connecting plate close to the main body toward the first shell wall. The third connecting plate is connected to an end of the second connecting plate away from the first connecting plate and is located between the first shell wall and the first connecting plate. The first electrode terminal is connected to the third connecting plate and passes through the first shell wall. The first terminal plate is located on the side of the first shell wall away from the first pole ear and is connected to the first electrode terminal.

[0323] Optionally, the distance between the first shell wall and the second shell wall along the first direction is D1 mm, and the area of ​​the second outer surface of the second shell wall is S mm. 2 , S is 36 to 500 times the square of D1.

[0324] Example

[0325] The following examples describe the present disclosure in more detail. These examples are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing. The instruments used in the examples are commercially available.

[0326] Example 1.

[0327] (i) Preparation of positive electrode

[0328] The active material (such as lithium iron phosphate) is mixed with a binder, conductive carbon, a dispersant, and a surfactant in a ratio of 97.5:1.8:0.4:0.3, and NMP (N-methylpyrrolidone) is used as a solvent. The mixture is stirred into a uniformly dispersed slurry, and the slurry is evenly coated on an Al foil. After drying and cold pressing, the target positive electrode sheet can be achieved. The coating weight can be selected as 350mg / 1540.25mm2, and the cold pressing density can be selected as 2.6g / cc;

[0329] (ii) Preparation of negative electrode sheet

[0330] The active material (such as graphite) is mixed with a binder, conductive carbon, and a dispersant in a ratio of 97.2:1.2:0.7:0.9, and deionized water is used as a solvent. The mixture is stirred into a uniformly dispersed slurry, and the slurry is evenly coated on the Cu foil. After drying and cold pressing, the target negative electrode sheet can be achieved. The coating weight can be selected as 165mg / 1540.25mm2, and the cold pressing density can be selected as 1.6g / cc;

[0331] (iii) Preparation of spacer

[0332] Using 7μm polyethylene film;

[0333] (iv) Preparation of electrolyte

[0334] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L;

[0335] (v) Preparation of electrode assembly

[0336] Forming an electrode assembly by winding the positive electrode sheet, the separator, and the negative electrode sheet;

[0337] (vi) Preparation of battery cells

[0338] The electrode assembly is placed in the shell, and the shell and cover are welded; after drying, the electrolyte is injected, and the battery cell is obtained through processes such as vacuum packaging, standing, formation, shaping, and coating insulation.

[0339] 4 to 6 , the spacing between the first shell wall 21 and the second shell wall 22 along the first direction Z is D1 mm, the dimension of the second shell wall 22 along the second direction X is D2 mm, and the dimension of the second shell wall 22 along the third direction Y is D3 mm. D1, D2, and D3 are 23, 276, and 69 mm, respectively.

[0340] Examples 2-10 and Comparative Examples 1-4 are shown in Table 1 below.

[0341] Test section

[0342] 1. Temperature test:

[0343] At a constant temperature of 25°C, the battery cells were subjected to five charge and discharge cycles using a charger and discharge machine, with both the charge and discharge rates at 1C. During the charge and discharge cycles, the temperatures of multiple locations on the battery cells were measured, and the highest temperature was recorded.

[0344] 2. Stiffness test

[0345] Place the cover of the battery cell downward and fix the battery cell. In the length direction (second direction), the distance between the fixing point of the battery cell and one end of the battery cell is 1 / 5 of the total length of the battery cell.

[0346] The press applies a downward force to the battery cell from the upper side of the battery cell. In the length direction, the distance between the force application point and the fixed point of the battery cell is 3 / 5 of the total length of the battery cell.

[0347] During the continuous pressure application process, the part of the battery cell located between the force application point and the fixed point tilts; when the tilt angle reaches 10°, the pressure value is recorded.

[0348] Table 1

[0349] Referring to Examples 1-10 and Comparative Examples 1-2, setting S to be greater than or equal to 36 times the square of D1 can improve the heat dissipation efficiency of the battery cell 6, reduce heat accumulation inside the battery cell, reduce the temperature rise of the battery cell during charging and discharging, and improve the cycle performance and cycle life of the battery cell.

[0350] Referring to Examples 1-10 and Comparative Examples 3-4, S is set to be less than or equal to 500 times the square of D1 to improve the stiffness and structural strength of the battery cell 6, reduce the deformation of the battery cell 6 when the battery cell 6 is subjected to external impact, enhance the anti-deformation ability of the battery cell, and improve the reliability of the battery cell 6.

[0351] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising: The housing comprises a first housing wall and a second housing wall which are arranged opposite to each other along a first direction, wherein an area of ​​a second outer surface of the second housing wall is smaller than or equal to an area of ​​a first outer surface of the first housing wall; an electrode assembly, contained in the housing and comprising a main body and a first electrode tab, wherein the main body is located between the first housing wall and the second housing wall in the first direction, and the first electrode tab extends from at least one end of the main body along a second direction intersecting the first direction; The distance between the first shell wall and the second shell wall along the first direction is D1 mm, and the area of ​​the second outer surface of the second shell wall is S mm. 2 , the S is 36 to 500 times the square of the D1.

2. The battery cell according to claim 1, wherein: S / D1 2 It is 45-175.

3. The battery cell according to claim 1 or 2, wherein: The dimension of the second shell wall along the second direction is D2 mm, the dimension of the second shell wall along the third direction is D3 mm, and the first direction, the second direction and the third direction are perpendicular to each other; D1, D2 and D3 satisfy: D2>D3>D1.

4. The battery cell according to claim 3, wherein: D2 / D3 is 4-10.2; optionally, D2 / D3 is 5-7.

5. The battery cell according to claim 3 or 4, wherein: D3 / D1 is 3-7; optionally, D3 / D1 is 3-5.

6. The battery cell according to any one of claims 3 to 5, wherein: D2 is 300-3000; optionally, D2 is 500-1000.

7. The battery cell according to any one of claims 1 to 6, wherein: The energy of the battery cell is 150×D1×S×10 -6 -600×D1×S×10 -6 , the unit of energy is Wh.

8. The battery cell according to any one of claims 1 to 7, wherein: The thickness of the second shell wall is 0.1 mm-0.8 mm; optionally, the thickness of the second shell wall is 0.2 mm-0.5 mm; further optionally, the thickness of the second shell wall is 0.3 mm.

9. The battery cell according to any one of claims 1 to 8, wherein: The area of ​​the second outer surface of the second shell wall is smaller than the area of ​​the first outer surface of the first shell wall; A first recess is provided at an end of the housing along the second direction, and the first recess is recessed from the second housing wall toward the first housing wall; In the first direction, at least a portion of the first electrode tab is located between a bottom wall of the first recess and the first shell wall.

10. The battery cell according to claim 9, wherein: The housing comprises two third shell walls arranged opposite to each other along a third direction, each of the third shell walls is connected to the first shell wall and the second shell wall, and the first direction, the second direction and the third direction are perpendicular to each other; In the third direction, at least a portion of the first electrode tab is located between two third shell walls; In the third direction, the size of the first pole ear is L1 mm, the distance between the two third shell walls is L2 mm, and L1 / L2 is 0.2-0.

9.

11. The battery cell according to claim 10, wherein: L1 / L2 is 0.5-0.

8.

12. The battery cell according to claim 10 or 11, wherein: In the third direction, the size of the main body is L3mm, and L3 / L2 is 0.9-0.99; optionally, L3 / L2 is 0.95-0.

98.

13. The battery cell according to any one of claims 9 to 12, wherein: The battery cell further includes a first electrode lead-out member, which is disposed on the first shell wall and electrically connected to the first electrode tab; At least part of the first electrode lead-out member is located outside the first shell wall; in the first direction, a projection of the part of the first electrode lead-out member located outside the first shell wall is at least partly located within a projection of the first recess.

14. The battery cell according to any one of claims 1 to 13, wherein: The battery cell further includes a first electrode lead-out member disposed on the first shell wall, the first electrode lead-out member includes a first connecting plate accommodated in the shell, and at least a portion of the first electrode tab is stacked and connected to the first connecting plate in the first direction; In the third direction, the size of the first pole ear is L1mm, the size of the first connecting plate is L4mm, and L1 / L4 is 0.6-1; optionally, L1 / L4 is 0.8-0.9; The first direction, the second direction and the third direction are perpendicular to each other.

15. The battery cell according to any one of claims 1 to 14, further comprising a first electrode lead-out member disposed on the first shell wall, the first electrode lead-out member comprising: A first connecting plate, contained in the housing, wherein at least a portion of the first pole lug is located on a side of the first connecting plate away from the first housing wall and connected to the first connecting plate; a second connecting plate extending from one end of the first connecting plate close to the main body toward the first shell wall; a third connecting plate, connected to an end of the second connecting plate away from the first connecting plate and located between the first shell wall and the first connecting plate; a first electrode terminal connected to the third connecting plate and passing through the first shell wall; as well as The first terminal plate is located on a side of the first shell wall away from the first electrode tab and is connected to the first electrode terminal.

16. The battery cell according to claim 15, wherein: The first terminal plate includes a first terminal portion and a second terminal portion, the first terminal portion is connected to the first electrode terminal, and the second terminal portion is protruding from a surface of the first terminal portion away from the first shell wall.

17. The battery cell according to any one of claims 1 to 16, comprising an insulating bracket, which is accommodated in the housing and arranged along the second direction with the main body; A first accommodating recess is provided on one side of the insulating bracket facing the main body; At least a portion of the first electrode tab extends into the first accommodating recess and is bent in the first accommodating recess.

18. The battery cell according to claim 17, wherein: The battery cell further includes a first electrode lead-out member disposed on the first shell wall; In the first direction, a portion of the insulating support is located between the first electrode lead-out member and the first shell wall.

19. The battery cell according to any one of claims 1 to 18, further comprising a first electrode lead-out member and an insulating member, wherein the first electrode lead-out member is disposed on the first shell wall and electrically connected to the first electrode tab, and the insulating member is used to insulate the electrode lead-out member from the first shell wall.

20. The battery cell according to any one of claims 1 to 19, wherein: The first shell wall is provided with a pressure relief mechanism; in the first direction, the pressure relief mechanism does not overlap with the main body.

21. The battery cell according to claim 20, wherein: The minimum distance H1 between the pressure relief mechanism and the edge of the first shell wall is 2 mm-5 mm.

22. The battery cell according to claim 20 or 21, wherein: The first shell wall is provided with a liquid injection hole, and the minimum distance H2 between the pressure relief mechanism and the liquid injection hole is greater than or equal to 1 mm.

23. The battery cell according to any one of claims 1 to 22, wherein: The AC internal resistance of the battery cell is less than or equal to 1 milliohm.

24. The battery cell according to any one of claims 1 to 23, wherein: The second shell wall is made of aluminum or steel, and the first shell wall is made of aluminum or steel.

25. The battery cell according to any one of claims 1 to 24, wherein: The electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces, the polarity of the first pole pieces is opposite to the polarity of the second pole pieces, and the plurality of first pole pieces and the plurality of second pole pieces are alternately stacked along the first direction; The first pole piece includes a first current collector and a first active material layer coated on the surface of the first current collector, and the second pole piece includes a second current collector and a second active material layer coated on the surface of the second current collector; The main body includes a portion of the first current collector coated with the first active material layer, a portion of the second current collector coated with the second active material layer, the first active material layer, and the second active material layer, and the first electrode tab includes a portion of the first current collector not coated with the first active material layer.

26. The battery cell according to any one of claims 1 to 25, wherein: The housing comprises a shell and a cover plate arranged along the first direction, the shell has an opening, and the cover plate covers the opening; The housing includes the second housing wall, and the cover includes the first housing wall.

27. The battery cell according to claim 26, wherein: A positioning groove is provided on a surface of the cover plate facing the shell, and a part of the main body is accommodated in the positioning groove.

28. A battery comprising a plurality of battery cells according to any one of claims 1 to 27.

29. An electrical device comprising the battery according to claim 28, wherein the battery is used to provide electrical energy.

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