Battery cell, battery device, and electric device

Abstract

Embodiments of the present application provide a battery monomer, a battery device and an electric device. The battery monomer comprises a shell, a first electrode terminal, an electrode assembly and a separator. The shell comprises a wall portion. The first electrode terminal is arranged on the wall portion. The electrode assembly is accommodated in the shell, and the electrode assembly comprises a first tab, which is electrically connected to the first electrode terminal. At least part of the separator is arranged between the first electrode terminal and the wall portion. The resistance value of the separator is greater than or equal to 1 Ω, and the melting point of the separator is greater than or equal to 450°.

Description

Battery cell, battery device and electric equipment TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, and more particularly, to a battery cell, a battery device and an electric equipment. BACKGROUND

[0002] Battery cells are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells is a research direction in the field of battery technology.

[0004] SUMMARY

[0005] The present application provides a battery cell, a battery device and an electric equipment, which can improve the reliability.

[0006] In a first aspect, the embodiments of the present application provide a battery cell, comprising a shell, a first electrode terminal, an electrode assembly and a separator. The shell comprises a wall portion. The first electrode terminal is arranged on the wall portion. The electrode assembly is accommodated in the shell, and the electrode assembly comprises a first tab, which is electrically connected to the first electrode terminal. At least part of the separator is arranged between the first electrode terminal and the wall portion, the resistance value of the separator is greater than or equal to 1Ω, and the melting point of the separator is greater than or equal to 450°.

[0007] When the battery cell appears thermal runaway due to internal short circuit or other reasons, the battery cell may maintain a high temperature state for a period of time. The separator is not easy to melt at a high temperature state, and it can be kept between the first electrode terminal and the wall portion, thereby reducing the risk of direct contact between the first electrode terminal and the wall portion. The separator has a resistance of 1Ω or more, so that even if the current from other battery cells or the current from an external power source is transmitted between the first electrode terminal and the wall portion through the separator, the separator can inhibit the current between the first electrode terminal and the wall portion, reduce the continuous heat generation of the first electrode terminal and the wall portion, reduce the thermal impact on other battery cells around, reduce the risk of thermal runaway of other battery cells, and improve the reliability.

[0008] In some embodiments, the resistance value of the separator is greater than or equal to 5Ω. When the battery cell appears thermal runaway, the separator with a larger resistance can further inhibit the current between the first electrode terminal and the wall portion, reduce the continuous heat generation of the first electrode terminal and the wall portion, reduce the risk of thermal runaway of other battery cells, and improve the reliability.

[0009] In some embodiments, the isolation member has a resistivity greater than or equal to 50000 Ω·cm. When the resistance of the isolation member meets the requirement, the isolation member with a larger resistivity can reduce the requirement for the volume of the isolation member. The isolation member of the embodiments of the present application has a higher resistivity, which can reduce the volume of the isolation member, save the volume and weight occupied by the isolation member, and improve the energy density of the battery monomer.

[0010] In some embodiments, the isolation member insulates and separates the first electrode terminal from the wall portion. The isolation member has electrical insulation, which can cut off the electrical connection between the first electrode terminal and the wall portion. When the battery monomer is in thermal runaway, the isolation member can maintain the insulation between the first electrode terminal and the wall portion, inhibit the current between the first electrode terminal and the wall portion, reduce the sustained heat generation of the first electrode terminal and the wall portion, reduce the risk of thermal runaway of other battery monomers, and improve the reliability.

[0011] In some embodiments, the wall portion is provided with an electrode lead-out hole. The first electrode terminal includes a terminal body and a first limiting portion, at least part of the terminal body is accommodated in the electrode lead-out hole, the first limiting portion is connected to the terminal body, and at least part of the first limiting portion protrudes from the outer peripheral surface of the terminal body. In the thickness direction of the wall portion, the first limiting portion at least partially overlaps with the wall portion, and at least part of the isolation member is located between the wall portion and the first limiting portion. The isolation member can be maintained between the first limiting portion and the wall portion, and when the battery monomer is in thermal runaway, the risk of direct contact between the first limiting portion and the wall portion is reduced, thereby inhibiting the current between the first electrode terminal and the wall portion and reducing the sustained heat generation of the first electrode terminal and the wall portion.

[0012] In some embodiments, the first electrode terminal further includes a second limiting portion connected to the terminal body, at least part of the second limiting portion protrudes from the outer peripheral surface of the terminal body, and in the thickness direction of the wall portion, the first limiting portion and the second limiting portion are located on both sides of the wall portion. The battery monomer further includes a sealing member, at least part of the sealing member is arranged between the second limiting portion and the wall portion in the thickness direction. The melting point of the sealing member is greater than or equal to 300°C. The sealing member has a higher melting point, which is not easy to melt when the battery monomer is in thermal runaway, thereby maintaining between the second limiting portion and the wall portion and reducing the risk of direct contact between the first electrode terminal and the wall portion.

[0013] In some embodiments, in the thickness direction, part of the sealing member and part of the isolation member are arranged in layers.

[0014] In some embodiments, the sealing member includes a first sealing portion and a second sealing portion connected to each other, at least a portion of the first sealing portion is located between the second limiting portion and the wall portion, and at least a portion of the second sealing portion is located in the electrode lead-out hole. The isolation member includes a first isolation portion and a second isolation portion connected to each other, at least a portion of the first isolation portion is located between the first limiting portion and the wall portion, and at least a portion of the second isolation portion is located in the electrode lead-out hole. In the radial direction of the electrode lead-out hole, the second isolation portion and the second sealing portion at least partially overlap in the electrode lead-out hole.

[0015] In some embodiments, the battery cell further includes a first insulation member, at least a portion of the first insulation member is arranged between the first electrode terminal and the wall portion. When the battery cell is in normal operation, the first insulation member can insulate the first electrode terminal from the wall portion to reduce the risk of short circuit of the battery cell. When the battery cell is in thermal runaway, even if the first insulation member melts at high temperature, the isolation member can remain between the first electrode terminal and the wall portion to suppress the current between the first electrode terminal and the wall portion.

[0016] In some embodiments, the melting point of the isolation member is higher than the melting point of the first insulation member. The isolation member has a higher melting point, and when the battery cell is in thermal runaway, even if the first insulation member melts at high temperature, the isolation member can remain between the first electrode terminal and the wall portion to suppress the current between the first electrode terminal and the wall portion.

[0017] In some embodiments, the isolation member is formed on at least one surface of the first electrode terminal, the wall portion, and one of the first insulation member.

[0018] In some embodiments, the material of the isolation member includes at least one of organic matter, inorganic metal oxide, and inorganic non-metallic material.

[0019] In some embodiments, the electrode assembly further includes a second tab opposite in polarity to the first tab, and the second tab is electrically connected to the wall portion. The wall portion and the first electrode terminal can serve as two electrodes of the battery cell and are located on the same side of the battery cell. When a plurality of battery cells are assembled into a group, it is convenient to realize the connection of the current collection component and the wall portion or the connection of the current collection component and the first electrode terminal, and the structure of the battery device is simplified. Although the wall portion and the first electrode terminal are opposite in polarity, the isolation member can suppress the current between the wall portion and the first electrode terminal when the battery cell is in thermal runaway, reduce the continuous heat generation of the first electrode terminal and the wall portion, and improve the reliability.

[0020] In some embodiments, the electrode assembly includes a positive electrode sheet, the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the positive electrode film layer includes a positive electrode active material, and the positive electrode active material includes a layered transition metal oxide. The layered transition metal oxide has a chemical formula of Li a Ni b Co c Md O e A f at least one of the compounds and modified compounds of Formula (I), 0.8≤a≤1.2, 0.8≤b≤0.95, 0

[0021] In the embodiments of the present application, b is greater than or equal to 0.8, and the battery monomer has a high nickel content. The battery monomer with a high nickel content has the advantages of high energy density, good low-temperature performance, good charge-discharge performance, etc. The thermal stability of the battery monomer with a high nickel content is relatively poor, and when thermal runaway occurs, the battery monomer generates more heat, and the temperature of the battery monomer rises higher. In the embodiments of the present application, a high-temperature-resistant isolation piece is arranged between the wall portion and the first electrode terminal, and the isolation piece can withstand the high temperature generated by the high-nickel battery monomer when thermal runaway occurs, thereby inhibiting the current between the first electrode terminal and the wall portion and reducing the continuous heat generation of the first electrode terminal and the wall portion. In the embodiments of the present application, b is less than or equal to 0.95, which can reduce the maximum temperature of the battery monomer when thermal runaway occurs and reduce the risk of melting failure of the isolation piece due to excessive temperature.

[0022] In some embodiments, the battery monomer further includes an electrolyte contained in the shell. The electrolyte includes a chain ester solvent, and the mass percentage content of the chain ester solvent in the electrolyte is 25.5wt% to 76.5wt%.

[0023] In the embodiments of the present application, the mass percentage content of the chain ester solvent is greater than or equal to 25.5wt%, so that the conductivity of the electrolyte is relatively high, which is beneficial to improving the liquid-phase transmission capacity of active ions and the rapid charging and discharging capacity of the battery monomer, thereby improving the rate performance of the battery monomer. The mass percentage content of the chain ester solvent is greater than or equal to 25.5wt%, which can also make the viscosity of the electrolyte system relatively low, and the electrolyte system is more prone to flow and infiltrate the electrode assembly, thereby improving the rapid charging and discharging capacity of the battery monomer and further improving the rate performance of the battery monomer. The chain ester solvent may face decomposition and gas production problems during the cycle charging and discharging process of the battery monomer. In the embodiments of the present application, the mass percentage content of the chain ester solvent is less than or equal to 76.5wt%, which can limit the internal pressure of the battery monomer, reduce the deformation of the shell, reduce the risk of failure of the battery monomer, and improve the reliability.

[0024] In some embodiments, the mass percentage content of the chain ester solvent in the electrolyte is 42.5wt% to 70wt%, which can further consider the rate performance and use reliability of the battery monomer and improve the cycle performance of the battery monomer.

[0025] In some embodiments, the thermal conductivity of the isolation piece is less than the thermal conductivity of the wall portion, and the thermal conductivity of the isolation piece is less than the thermal conductivity of the first electrode terminal. Compared with the wall portion and the first electrode terminal, the isolation piece has a smaller thermal conductivity, so that the heat conduction can be slowed down when the battery cell is in thermal runaway, the temperature rise of the isolation piece is reduced, and the risk of melting failure of the isolation piece is reduced.

[0026] In some embodiments, the thermal conductivity of the wall portion is less than the thermal conductivity of the first electrode terminal. When the battery cell is in thermal runaway, the wall portion has a larger heating area and is prone to heat up. The wall portion has a smaller thermal conductivity, so that the heat conduction from the wall portion to the isolation piece is reduced, thereby reducing the temperature rise of the isolation piece and reducing the risk of melting failure of the isolation piece.

[0027] In some embodiments, the shell includes a housing and an end cover, the housing includes a side wall and an end wall, the side wall surrounds the electrode assembly, and the end wall and the end cover are opposite to each other and are sealingly connected to the side wall. The wall portion is the end cover or the end wall.

[0028] In some embodiments, the side wall and the end wall are integrally formed. In some embodiments, the battery cell is a cylindrical battery cell, and the diameter of the cylindrical battery cell is greater than or equal to 35 mm and less than or equal to 70 mm. The cylindrical battery cell has the advantages of mature production process, good consistency, good heat dissipation performance, and high group efficiency. By setting the diameter of the cylindrical battery cell to be greater than or equal to 35 mm, the capacity and energy density of the cylindrical battery cell can be improved. The diameter of the cylindrical battery cell is related to the heat generation when the cylindrical battery cell is in thermal runaway. By setting the diameter of the cylindrical battery cell to be less than or equal to 70 mm, the maximum temperature of the cylindrical battery cell in thermal runaway is limited, and the risk of melting failure of the isolation piece is reduced.

[0029] In a second aspect, the embodiments of the present application provide a battery device, which includes a plurality of battery cells provided by any one of the embodiments of the first aspect.

[0030] In some embodiments, the at least two battery cells are connected in parallel.

[0031] In a third aspect, the embodiments of the present application provide a power utilization device, which includes the battery device provided by any one of the embodiments of the second aspect, and the battery device is used to provide electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] FIG. 1 is a structural schematic view of a vehicle provided by some embodiments of the present application;

[0034] FIG. 2 is a schematic diagram of a battery device according to some embodiments of the present application;

[0035] FIG. 3 is a schematic diagram of a battery module according to some embodiments of the present application;

[0036] FIG. 4 is a schematic diagram of a battery cell according to some embodiments of the present application;

[0037] FIG. 5 is an exploded schematic diagram of the battery cell according to some embodiments of the present application;

[0038] FIG. 6 is a cross-sectional schematic diagram of an electrode assembly of the battery cell according to some embodiments of the present application;

[0039] FIG. 7 is a schematic diagram of an expanded positive electrode sheet of the electrode assembly of the battery cell according to some embodiments of the present application;

[0040] FIG. 8 is a schematic diagram of an expanded negative electrode sheet of the electrode assembly of the battery cell according to some embodiments of the present application;

[0041] FIG. 9 is a partial cross-sectional schematic diagram of the battery cell according to some embodiments of the present application;

[0042] FIG. 10 is an enlarged schematic diagram of the box in FIG. 9;

[0043] FIG. 11 is an enlarged schematic diagram of the circle in FIG. 10;

[0044] FIG. 12 is an enlarged schematic diagram of the circle in FIG. 11;

[0045] FIG. 13 is a partial cross-sectional schematic diagram of the battery cell according to some embodiments of the present application;

[0046] FIG. 14 is an enlarged schematic diagram of the box in FIG. 13;

[0047] FIG. 15 is a partial cross-sectional schematic diagram of the battery cell according to some embodiments of the present application;

[0048] FIG. 16 is an enlarged schematic diagram of the box in FIG. 15;

[0049] FIG. 17 is an enlarged schematic diagram of the box in FIG. 16;

[0050] FIG. 18 is a partial cross-sectional schematic diagram of the battery cell according to some embodiments of the present application;

[0051] FIG. 19 is an enlarged schematic diagram of the box in FIG. 18;

[0052] FIG. 20 is a partial cross-sectional schematic diagram of the battery cell according to some embodiments of the present application;

[0053] FIG. 21 is an enlarged schematic diagram of the box in FIG. 20;

[0054] FIG. 22 is a partial cross-sectional view of a battery cell according to some embodiments of the present application;

[0055] FIG. 23 is an enlarged view of the box in FIG. 22;

[0056] FIG. 24 is a partial cross-sectional view of a battery cell according to some embodiments of the present application;

[0057] FIG. 25 is a partial cross-sectional view of a battery cell according to some embodiments of the present application;

[0058] FIG. 26 is an exploded view of a battery cell according to some embodiments of the present application;

[0059] FIG. 27 is a partial cross-sectional view of a battery cell according to some embodiments of the present application;

[0060] FIG. 28 is a simplified schematic view of a battery device according to some embodiments of the present application.

[0061] Reference signs are explained as follows:

[0062] 1, vehicle; 2, battery device; 3, controller; 4, motor; 5, case; 5a, first case; 5b, second case; 6, battery module; 7, battery cell; 7a, battery unit; 8, current collecting member;

[0063] 10, electrode assembly; 10a, first tab; 10b, second tab; 11, positive electrode sheet; 111, positive electrode current collector; 1111, positive electrode tab; 112, positive electrode film layer; 12, negative electrode sheet; 121, negative electrode current collector; 1211, negative electrode tab; 122, negative electrode film layer; 13, separator;

[0064] 20, housing; 20a, wall portion; 21, case; 211, end wall; 2111, electrode lead-out hole; 2112, first surface; 2113, second surface; 2114, first recess; 212, side wall; 22, end cap;

[0065] 30, first electrode terminal; 31, terminal body; 32, first stopper portion; 33, second stopper portion; 331, fourth recess;

[0066] 40, spacer; 40a, first ceramic member; 40b, second ceramic member; 41, first spacer portion; 42, second spacer portion; 43, third spacer portion;

[0067] 50, third insulating member;

[0068] 60, sealing member; 61, first sealing portion; 62, second sealing portion;

[0069] 70 first insulating member; 71 first insulating portion; 72 second insulating portion; 73 second recess;

[0070] 80 second insulating member; 80a third recess;

[0071] 90 second electrode terminal;

[0072] Z thickness direction. DETAILED DESCRIPTION

[0073] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0074] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, and are not intended to describe a particular order or primary and secondary relationship.

[0075] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0076] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0077] The term "and / or", as used in the specification and in claims of the application, is to be taken as a mere description of a relationship between associated objects, and can represent three relationships, for example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0078] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0079] "Multiple" appearing in the present application means two or more (including two).

[0080] At present, from the development of market situation, the application of battery is more and more widely. The battery is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, aerospace and other fields. With the continuous expansion of the application field of battery, the demand of its market is also increasing.

[0081] The battery device generally refers to a single physical module including a plurality of battery cells to provide higher voltage and capacity. The battery cell can be the smallest unit constituting the battery device.

[0082] The battery cell generally includes a housing, an electrode assembly contained in the housing, and a positive electrode lead-out portion and a negative electrode lead-out portion provided on the housing; the electrode assembly generally includes a positive electrode sheet and a negative electrode sheet, the positive electrode lead-out portion is electrically connected to the positive electrode sheet, and the negative electrode lead-out portion includes the negative electrode sheet. The positive electrode lead-out portion and the negative electrode lead-out portion are used to be electrically connected with an external circuit to realize charging or discharging of the battery cell. Exemplarily, at least one of the positive electrode lead-out portion and the negative electrode lead-out portion includes an electrode terminal provided on the housing.

[0083] When a certain battery cell in the battery device appears thermal runaway due to an accident (such as internal short circuit), the battery cell can maintain a high temperature state for a period of time. Under the high temperature state, the insulating member for blocking the conductive path between the positive electrode lead-out portion and the negative electrode lead-out portion can melt, causing the current from other battery cells or the current from the external power source to continue to transmit between the positive electrode lead-out portion and the negative electrode lead-out portion, causing the battery cell to continuously generate heat locally, thereby causing the risk of abnormal temperature rise and thermal runaway of other normal battery cells, leading to thermal spread.

[0084] For example, when the conductive path between the positive and negative electrode lead-out portions of the battery cell is formed, a closed loop is formed between the battery cell and a battery cell connected in parallel to the battery cell, and current continuously flows through the battery cell, causing the battery cell to continuously generate heat locally.

[0085] In view of this, the battery cell provided in the embodiments of the present application sets a separation piece with a high melting point and a large resistance between the electrode terminal and the shell, so as to inhibit the current between the positive and negative electrodes of the battery cell when the battery cell is in thermal runaway, reduce the continuous heat generation of the battery in thermal runaway, reduce the risk of thermal runaway of other battery cells, and improve reliability.

[0086] The battery cell described in the embodiments of the present application is suitable for a battery device and a power consumption device using the battery device. The power consumption device can be a device using the battery device as a power source or various energy storage systems using the battery device as an energy storage element. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric aircraft toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0087] The following embodiments are described for convenience with the power consumption device being a vehicle as an example.

[0088] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0089] As shown in FIG. 1, the vehicle 1 is internally provided with a battery device 2, which can be arranged at the bottom, head or tail of the vehicle 1. The battery device 2 can be used for power supply of the vehicle 1, for example, the battery device 2 can be used as an operating power source of the vehicle 1.

[0090] The vehicle 1 can further include a controller 3 and a motor 4, and the controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the working power demand of the vehicle 1 during starting, navigation and driving.

[0091] In some embodiments of the present application, the battery device 2 can not only be used as an operating power source of the vehicle 1, but also be used as a driving power source of the vehicle 1, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1.

[0092] FIG. 2 is a schematic diagram of a battery device provided by some embodiments of the present application.

[0093] In some embodiments, the battery device 2 can include one or more battery cell assemblies for providing voltage and capacity.

[0094] The battery cell assembly can include a plurality of battery cells (not shown in FIG. 2) connected in series, in parallel, or in a mixed connection through a busbar component. The mixed connection means that there are both series and parallel connections among the plurality of battery cells.

[0095] The battery cell can be a secondary battery cell, which means that the battery cell can be used continuously by activating the active material through charging after discharging the battery cell.

[0096] As an example, the battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, or the like.

[0097] As an example, the battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, the prismatic battery cell including a square battery cell, a blade battery cell, a multi-prismatic battery cell, for example, a hexagonal battery cell, or the like.

[0098] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module 6 formed by arranging and fixing a plurality of battery cells into one independent module. As an example, the battery module 6 can be formed by bundling a plurality of battery cells with a cable tie.

[0099] In some embodiments, the battery device 2 can be a battery pack including a case 5 and one or more battery cell assemblies accommodated in the case 5. As an example, the battery cell assembly can be a battery module 6, which can be accommodated in the case by fixing the battery module 6 in the case. As an example, the battery cell assembly can also be accommodated in the case by directly fixing a plurality of battery cells in the case.

[0100] In some embodiments, the case 5 for accommodating the battery cell can be of various structures.

[0101] In some embodiments, the case 5 can include a first case 5a and a second case 5b. The first case 5a and the second case 5b are coupled so that an enclosed space is formed inside the case 5 to accommodate the battery cell assembly. The enclosed here means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0102] In some embodiments, the case 5 can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame so that an enclosed space is formed inside the case to accommodate the battery cell assembly. As an example, the frame can include a plurality of side beams.

[0103] In some embodiments, the box 5 can be part of the chassis structure of the vehicle. For example, part of the box 5 can be part of the floor of the vehicle, or part of the box 5 can be part of the cross beam and longitudinal beam of the vehicle.

[0104] In some embodiments, the battery device 2 can be an energy storage device.

[0105] The energy storage device can be used in energy storage power stations, wind power systems, solar power systems, mobile power systems, or temporary power supply systems, etc. The energy storage device can store electrical energy as needed and output electrical energy at the appropriate time. For example, the energy storage device can store electrical energy during the off-peak period of electricity consumption, and provide electrical energy for the relevant users or electrical equipment during the peak period of electricity consumption.

[0106] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0107] FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2.

[0108] In some embodiments, as shown in FIG. 3, the battery cell 7 is multiple, and the multiple battery cells 7 are connected in series or in parallel or in hybrid connection to form a battery module 6. Multiple battery modules 6 are connected in series or in parallel or in hybrid connection to form a whole and are accommodated in the box.

[0109] The multiple battery cells 7 in the battery module 6 can be electrically connected through a busbar component to realize parallel connection, series connection or hybrid connection of the multiple battery cells 7 in the battery module 6. The busbar component can be one or more, and each busbar component is used to electrically connect at least two battery cells 7.

[0110] FIG. 4 is a structural schematic diagram of a battery cell in some embodiments of the present application; FIG. 5 is an exploded schematic diagram of the battery cell shown in FIG. 4; FIG. 6 is a cross-sectional view of an electrode assembly of the battery cell provided in some embodiments of the present application; FIG. 7 is a schematic diagram of an expanded positive electrode sheet of the electrode assembly of the battery cell provided in some embodiments of the present application; and FIG. 8 is a schematic diagram of an expanded negative electrode sheet of the electrode assembly of the battery cell provided in some embodiments of the present application.

[0111] Referring to FIGS. 4 to 8, the present application provides a battery cell 7, which includes an outer shell 20 and an electrode assembly 10 accommodated in the outer shell 20.

[0112] In some embodiments, the outer shell 20 can be a steel shell, an aluminum shell, or a composite metal shell (such as a copper-aluminum composite shell), etc.

[0113] The outer shell 20 can be a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and the electrolyte is formed inside the outer shell 20.

[0114] In some embodiments, the outer shell 20 of the battery cell 7 is a cylindrical shell, a square shell, a prismatic shell, or a shell of other shapes.

[0115] In some embodiments, the outer shell 20 includes a shell body 21 having an opening and an end cap 22 connected to the shell body 21 and covering the opening.

[0116] The shell body 21 is a component for cooperating with the end cap 22 to form an internal cavity of the battery cell 7, which can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0117] The shell body 21 and the end cap 22 can be separate components. For example, the shell body 21 can be provided with an opening, and the end cap 22 can be used to cover the opening to form the internal cavity of the battery cell 7.

[0118] The shell body 21 can be of various shapes and sizes, such as a cuboid or a cylinder. In particular, the shape of the shell body 21 can be determined according to the specific shape and size of the electrode assembly 10. The shell body 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0119] The end cap 22 can be shaped to fit the shell body 21. The material of the end cap 22 can be the same as or different from that of the shell body 21. Optionally, the end cap 22 can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap 22 is less likely to deform when subjected to extrusion or impact, and the battery cell 7 can have higher structural strength and improved reliability.

[0120] The end cap 22 can be connected to the shell body 21 by welding, bonding, clamping, or other means.

[0121] The shell body 21 can be open at one end or both ends. In some examples, the shell body 21 can be open at one side, and the end cap 22 can be provided as one and cover the shell body 21. In other examples, the shell body 21 can be open at both ends, and the end cap 22 can be provided as two and cover the two openings of the shell body 21.

[0122] The electrode assembly 10 is a component in the battery cell 7 where electrochemical reactions occur. The shell body 21 can contain one or more electrode assemblies 10.

[0123] In some embodiments, the electrode assembly 10 includes a positive electrode sheet 11, a negative electrode sheet 12, and a separator 13, the positive electrode sheet 11 and the negative electrode sheet 12 being opposite in polarity, and the separator 13 separating the positive electrode sheet 11 and the negative electrode sheet 12.

[0124] At least a portion of the separator film 13 is positioned between the positive electrode sheet 11 and the negative electrode sheet 12. During charging and discharging of the battery cell 7, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive electrode sheet 11 and the negative electrode sheet 12. The separator film 13, which is provided between the positive electrode sheet 11 and the negative electrode sheet 12, can function to prevent short-circuiting of the positive and negative electrodes while allowing the active ions to pass through.

[0125] In some embodiments, the positive electrode sheet 11 can include a positive electrode current collector 111 and a positive electrode film layer 112 provided on at least one surface of the positive electrode current collector 111.

[0126] As an example, the positive electrode current collector 111 has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer 112 is provided on either one or both of the two opposite surfaces of the positive electrode current collector 111.

[0127] As an example, the positive electrode current collector 111 can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, etc. can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, a silver alloy, etc.) on a polymer material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0128] As an example, the positive electrode film layer 112 includes a positive electrode active material, which can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or in combination of two or more. Examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co0.2 Mn 0.3 O2(also can be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al 0.05 O2), and modified compounds thereof. The modified compounds refer to substances obtained by modification means such as doping or coating on the basis of the above-mentioned substances.

[0129] In some embodiments, the negative electrode sheet 12 can include a negative electrode current collector 121.

[0130] As an example, the negative electrode current collector 121 can adopt a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, etc. can be adopted. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0131] As an example, the negative electrode sheet 12 can include the negative electrode current collector 121 and the negative electrode film layer 122 provided on at least one surface of the negative electrode current collector 121.

[0132] As an example, the negative electrode current collector 121 has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer 122 is provided on any one or both of the two opposite surfaces of the negative electrode current collector 121.

[0133] As an example, the negative electrode film layer 122 includes a negative electrode active material, which can employ a negative electrode active material for a battery cell 7 known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery cell 7 can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0134] In some embodiments, the material of the positive electrode current collector 111 can be aluminum, and the material of the negative electrode current collector 121 can be copper.

[0135] In some embodiments, the separator film 13 includes a base film. The base film of the present application can employ any known porous structure film having good chemical stability and mechanical stability.

[0136] As an example, the main material of the base film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, and ceramic. The base film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the base film is a multi-layer composite film, the materials of the respective layers can be the same or different.

[0137] An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can be applied to the surface of the base film.

[0138] The separator film 13 can be a single component located between the positive electrode sheet 11 and the negative electrode sheet 12, or can be attached to the surface of the positive electrode sheet 11 or the surface of the negative electrode sheet 12.

[0139] In some embodiments, the separator film 13 is a solid electrolyte. The solid electrolyte is provided between the positive electrode sheet 11 and the negative electrode sheet 12, and functions to transport ions and separate the positive electrode and the negative electrode.

[0140] In some embodiments, the battery cell 7 further includes an electrolyte, which functions to conduct ions between the positive electrode sheet 11 and the negative electrode sheet 12. The electrolyte of the present application can be selected as needed. The electrolyte can be liquid, gel, or solid.

[0141] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0142] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalato borate, lithium difluoro dioxalato borate, lithium difluoro dioxalato phosphonate, and lithium tetrafluoro oxalato phosphonate.

[0143] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and a crown ether.

[0144] In some embodiments, the electrolyte solution can also optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and / or an additive that improves certain properties of the battery cell, such as an additive that improves overcharge / rapid charge performance of the battery cell, an additive that improves high-temperature performance of the battery cell, an additive that improves low-temperature performance of the battery cell, and / or the like.

[0145] In some embodiments, the gel-state electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0146] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and / or a composite solid-state electrolyte.

[0147] As an example, the polymer of the polymer solid-state electrolyte can include a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid, a cellulose, and / or the like.

[0148] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0149] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0150] In some embodiments, the electrode assembly 10 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0151] In some embodiments, the electrode assembly 10 is a wound structure. The positive electrode sheet 11 and the negative electrode sheet 12 are wound into a wound structure.

[0152] In some embodiments, the electrode assembly 10 is a stacked structure.

[0153] As an example, a plurality of positive electrode sheets 11 and a plurality of negative electrode sheets 12 can be alternately stacked. As an example, a plurality of positive electrode sheets 11 can be provided, and the negative electrode sheet 12 can be folded to form a plurality of folded segments that are stacked. One positive electrode sheet 11 can be sandwiched between adjacent folded segments.

[0154] As an example, the positive electrode sheet 11 and the negative electrode sheet 12 can be folded to form a plurality of folded segments that are stacked.

[0155] As an example, a plurality of isolation films 13 can be provided between any adjacent positive electrode sheets 11 or negative electrode sheets 12.

[0156] As an example, the isolation film 13 can be continuously provided between any adjacent positive electrode sheets 11 or negative electrode sheets 12 by folding or winding.

[0157] In some embodiments, the electrode assembly 10 can have a cylindrical shape, a flat shape, or a polygonal shape.

[0158] In some embodiments, the positive current collector 111 can include a positive electrode tab 1111, and the negative current collector 121 can include a negative electrode tab 1211. The positive electrode tab 1111 and the negative electrode tab 1211 can be used to transmit current. As an example, at least a portion of the positive electrode tab 1111 is not coated with the positive electrode film layer 112, and at least a portion of the negative electrode tab 1211 is not coated with the negative electrode film layer 122.

[0159] In some embodiments, the battery cell 7 includes a positive electrode lead and a negative electrode lead. The positive electrode lead is electrically connected to the positive electrode sheet 11, and the negative electrode lead is electrically connected to the negative electrode sheet 12.

[0160] The positive electrode lead and the negative electrode lead are used to be electrically connected to an external circuit to charge or discharge the battery cell 7.

[0161] In some embodiments, the positive electrode lead includes a positive electrode terminal. At least a portion of the positive electrode terminal is exposed to the outside of the battery cell 7 to facilitate connection with a busbar member.

[0162] As an example, the positive terminal can be a separately formed component that is mounted to the housing 20. Alternatively, the positive terminal can also be formed as part of the housing 20.

[0163] In some examples, the positive terminal is directly connected to the positive tab 11; in other examples, the positive terminal and the positive tab 11 are indirectly connected by other conductive structures, such as a positive adapter tab.

[0164] In some embodiments, the positive terminal is connected to the end cap 22 by welding, riveting, clamping, or other means.

[0165] In some embodiments, the negative lead-out portion includes a negative terminal. At least a portion of the negative terminal is exposed to the outside of the battery cell 7 to facilitate connection to a busbar component.

[0166] As an example, the negative terminal can be a separately formed component that is mounted to the housing 20. Alternatively, the negative terminal can also be formed as part of the housing 20.

[0167] In some examples, the negative terminal is directly connected to the negative tab 12; in other examples, the negative lead-out portion further includes other conductive structures, such as a negative adapter tab, that connect the negative terminal and the negative tab 12.

[0168] In some embodiments, the negative terminal is connected to the end cap 22 by welding, riveting, clamping, or other means.

[0169] FIG. 9 is a partial cross-sectional view of a battery cell according to some embodiments of the present application; FIG. 10 is an enlarged view of the boxed portion of FIG. 9; FIG. 11 is an enlarged view of the circled portion of FIG. 10; and FIG. 12 is an enlarged view of the circled portion of FIG. 11.

[0170] Referring to FIGS. 4-12, a battery cell 7 according to some embodiments of the present application includes a housing 20, a first electrode terminal 30, an electrode assembly 10, and a separator 40. The housing 20 includes a wall portion 20a. The first electrode terminal 30 is disposed on the wall portion 20a. The electrode assembly 10 is housed within the housing 20. The electrode assembly 10 includes a first tab 10a that is electrically connected to the first electrode terminal 30. At least a portion of the separator 40 is disposed between the first electrode terminal 30 and the wall portion 20a. The separator 40 has an electrical resistance value greater than or equal to 1 Ω, and a melting point greater than or equal to 450°.

[0171] As an example, the wall portion 20a can be an end cap 22, or a wall of the housing 21.

[0172] The first tab 10a can be a positive tab 1111 or a negative tab 1211. The polarity of the first electrode terminal 30 corresponds to the polarity of the first tab 10a. In some examples, the first tab 10a is a positive tab 1111 and the first electrode terminal 30 is a positive terminal. In other examples, the first tab 10a is a negative tab 1211 and the first electrode terminal 30 is a negative terminal.

[0173] The first tab 10a can be directly connected to the first electrode terminal 30 or indirectly connected to the first electrode terminal 30 through other conductive structures.

[0174] The wall portion 20a can be electrically charged or not. In some examples, one of the first electrode terminal 30 and the wall portion 20a is electrically connected to the positive tab 1111 and the other is electrically connected to the negative tab 1211. In other examples, the wall portion 20a is insulated from the positive tab 1111 and the negative tab 1211.

[0175] The spacer 40 can be disposed entirely between the first electrode terminal 30 and the wall portion 20a or only a portion thereof can be disposed between the first electrode terminal 30 and the wall portion 20a.

[0176] As an example, the resistance value of the spacer 40 can be the resistance value of the spacer 40 in a normal temperature state (e.g., 25°C).

[0177] As an example, the resistance value of the spacer 40 can be the minimum resistance of the portion of the spacer 40 between the first electrode terminal 30 and the wall portion 20a.

[0178] As an example, the resistance value of the spacer 40 can be 1Ω, 2Ω, 3Ω, 4Ω, 5Ω, 8Ω, 10Ω, 15Ω, 20Ω, 30Ω, 40Ω, 50Ω, 80Ω, 100Ω, or 500Ω.

[0179] As an example, the spacer 40 can be an insulating member or a conductive member having a resistance greater than or equal to 1Ω. Alternatively, the spacer 40 is an insulating member.

[0180] As an example, the melting point of the spacer 40 can be 450°, 500°, 550°, 600°, 650°, 700°, 750°, 800°, 850°, 900°, 950°, or 1000°.

[0181] In the case where the spacer 40 includes a plurality of materials, it is not necessary that the melting point of all the materials be 450°C or higher. As an example, the spacer 40 includes a material having a melting point of 450°C or higher. Alternatively, the melting point of a main material (a material having the largest volume ratio) constituting the spacer 40 is 450°C or higher.

[0182] As an example, the spacer 40 can be provided independently between the first electrode terminal 30 and the wall portion 20a, or can be attached to the first electrode terminal 30, attached to the wall portion 20a, or attached to other components.

[0183] When the battery cell 7 is in thermal runaway due to internal short circuit or other reasons, the battery cell 7 can maintain a high temperature state for a period of time. The spacer 40 is not easy to melt at a high temperature state, and can be kept between the first electrode terminal 30 and the wall portion 20a, thereby reducing the risk of direct contact between the first electrode terminal 30 and the wall portion 20a; the spacer 40 has a resistance of 1Ω or more, and even if the current from other battery cells 7 or the current from an external power source is transmitted between the first electrode terminal 30 and the wall portion 20a through the spacer 40, the spacer 40 can inhibit the current between the first electrode terminal 30 and the wall portion 20a, reduce the sustained heat generation of the first electrode terminal 30 and the wall portion 20a, reduce the thermal impact on other battery cells in the surrounding, reduce the risk of thermal runaway of other battery cells 7, and improve reliability.

[0184] As an example, when two electrodes of a normal battery cell 7 are electrically connected to the wall portion 20a and the first electrode terminal 30 of the battery cell 7 in thermal runaway, respectively, the spacer 40 can inhibit the current, reduce the sustained heat generation of the first electrode terminal 30 and the wall portion 20a, reduce the thermal impact on other battery cells in the surrounding, reduce the risk of thermal runaway of other battery cells 7, and improve reliability.

[0185] In some embodiments, the resistance value of the spacer 40 is greater than or equal to 5Ω. When the battery cell 7 is in thermal runaway, the spacer 40 with a larger resistance can further inhibit the current between the first electrode terminal 30 and the wall portion 20a, reduce the sustained heat generation of the first electrode terminal 30 and the wall portion 20a, reduce the risk of thermal runaway of other battery cells 7, and improve reliability.

[0186] In some embodiments, the resistance value of the spacer 40 is greater than or equal to 10Ω.

[0187] In some embodiments, the specific resistance of the spacer 40 is greater than or equal to 50000Ω·cm.

[0188] As an example, the specific resistance of the spacer 40 can be the specific resistance of the spacer 40 at a normal temperature state.

[0189] As an example, the specific resistance of the spacer 40 can be 50000Ω·cm, 55000Ω·cm, 60000Ω·cm, 65000Ω·cm, 70000Ω·cm, 80000Ω·cm, 90000Ω·cm, 100000Ω·cm, or 200000Ω·cm.

[0190] When the resistance of the isolation member 40 meets the requirement, the isolation member 40 with a larger resistivity can reduce the requirement on the volume of the isolation member 40. The isolation member 40 in the embodiments of the present application has a higher resistivity, so that the volume of the isolation member 40 can be reduced, the volume and weight occupied by the isolation member 40 can be saved, and the energy density of the battery monomer 7 can be improved.

[0191] In some embodiments, the isolation member 40 insulates and separates the first electrode terminal 30 from the wall portion 20a.

[0192] As an example, the isolation member is made of an insulating material.

[0193] The isolation member 40 has electrical insulation, which can cut off the electrical connection between the first electrode terminal 30 and the wall portion 20a. When the battery monomer 7 is in thermal runaway, the isolation member 40 can maintain the insulation between the first electrode terminal 30 and the wall portion 20a, so as to inhibit the current between the first electrode terminal 30 and the wall portion 20a, reduce the continuous heat generation of the first electrode terminal 30 and the wall portion 20a, reduce the risk of thermal runaway of other battery monomers 7, and improve the reliability.

[0194] In some embodiments, the material of the isolation member 40 includes at least one of an organic matter, an inorganic metal oxide, and an inorganic non-metallic material.

[0195] As an example, the inorganic metal oxide includes at least one of zirconium oxide and aluminum oxide.

[0196] As an example, the inorganic non-metallic material includes at least one of silicon dioxide and silicate.

[0197] As an example, the organic matter includes a fluorine-based resin or an imide-based resin. For example, the organic matter includes polyimide.

[0198] In some embodiments, the isolation member 40 can include an oxide film or a nitride film formed on the surface of the first electrode terminal 30. Alternatively, the isolation member 40 includes an oxide film. For example, the material of the first electrode terminal 30 is aluminum or an aluminum alloy, and the isolation member 40 includes an aluminum oxide film formed on the surface of the first electrode terminal 30.

[0199] Alternatively, the isolation member 40 is provided as an oxidation prevention layer.

[0200] In other embodiments, the isolation member 40 can include an oxide film or a nitride film formed on the surface of the wall portion 20a. For example, the material of the wall portion 20a is aluminum or an aluminum alloy, and the isolation member 40 includes an aluminum oxide film formed on the surface of the wall portion 20a.

[0201] In other embodiments, the spacer 40 includes a coating applied to a surface of the first electrode terminal 30 and / or a surface of the wall portion 20a. Alternatively, the coating can be applied to a surface of another component (e.g., a first insulator described later).

[0202] In some examples, the coating includes an inorganic metal oxide.

[0203] Optionally, the inorganic metal oxide includes at least one of zirconium oxide and aluminum oxide.

[0204] Optionally, the inorganic metal oxide has a mass content in the coating of greater than or equal to 45%. The inorganic metal oxide has a high melting point and good electrical insulation.

[0205] In other examples, the coating includes a ceramic and a binder.

[0206] Optionally, the ceramic can be ceramic particles or ceramic fibers.

[0207] Optionally, the ceramic includes at least one of aluminum oxide, zirconium oxide, titanium oxide, or silicon oxide.

[0208] Optionally, the binder can be an inorganic binder or a resin binder. The inorganic binder can be a binder of an alkali metal silicate system, a phosphate system, or a silica sol system, etc.

[0209] For example, a slurry composed of ceramic particles or ceramic fibers, a binder, and a dispersion medium is applied to a surface of the first electrode terminal 30 or the wall portion 20a, and the slurry is dried to remove the dispersion medium, whereby an electrically insulating coating can be made.

[0210] In yet other examples, the coating includes an inorganic nonmetallic material.

[0211] Optionally, the inorganic nonmetallic material has a mass content in the coating of 15% to 70%.

[0212] Optionally, the inorganic nonmetallic material includes at least one of silicon dioxide and a silicate.

[0213] In still other examples, the coating includes a perfluoroalkoxy polymer and silicon dioxide.

[0214] Optionally, the silicon dioxide has a mass content in the coating of 3% to 75%.

[0215] Optionally, the coating includes a perfluoroalkoxy polymer and a ceramic.

[0216] In other embodiments, the spacer 40 includes a ceramic layer on a surface of the first electrode terminal 30 by vapor deposition or thermal spraying, etc.; and / or, the spacer 40 includes a ceramic layer on a surface of the first electrode terminal 30 by vapor deposition or thermal spraying, etc.

[0217] In other embodiments, the spacer 40 includes a resin layer. For example, a resin having high heat resistance such as a fluorine-based or imide-based resin is applied or electrodeposited to the first electrode terminal 30 to form a resin layer attached to the first electrode terminal 30; for example, a resin having high heat resistance such as a fluorine-based or imide-based resin is applied or electrodeposited to the wall portion 20a to form a resin layer attached to the wall portion 20a.

[0218] In other embodiments, the spacer 40 includes an insulating film; the insulating film is attached to a surface of the first electrode terminal 30 or the wall portion 20a. Optionally, the insulating film is a polyimide film.

[0219] In some embodiments, the thickness of the spacer 40 is 0.001 mm to 2 mm.

[0220] For example, the thickness of the spacer 40 is 0.001 mm, 0.002 mm, 0.003 mm, 0.005 mm, 0.008 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm, 0.80 mm, 0.85 mm, 0.90 mm, 0.95 mm, 1.00 mm, 1.20 mm, 1.50 mm, 1.80 mm, or 2.00 mm.

[0221] Optionally, the thickness of the spacer 40 is 0.01 mm to 0.75 mm.

[0222] Optionally, the thickness of the spacer 40 is 0.05 mm to 0.5 mm.

[0223] In some embodiments, the wall portion 20a is provided with an electrode lead-out hole 2111.

[0224] For example, the electrode lead-out hole 2111 penetrates the wall portion 20a in the thickness direction Z of the wall portion 20a.

[0225] For example, the electrode lead-out hole 2111 is a circular hole, a square hole, a racetrack-shaped hole, an elliptical hole, or a hole of another shape.

[0226] In some embodiments, the first electrode terminal 30 includes a terminal body 31 and a first stopper 32, at least a portion of the terminal body 31 is accommodated in the electrode lead-out hole 2111, the first stopper 32 is connected to the terminal body 31, and at least a portion of the first stopper 32 protrudes from the outer peripheral surface of the terminal body 31.

[0227] In some examples, the first limiting portion 32 and the terminal body 31 can be integrally formed. In other examples, the first limiting portion 32 and the terminal body 31 are separately formed and connected by welding, riveting, bonding or other means.

[0228] The first limiting portion 32 can be located on the inner side of the wall portion 20a or on the outer side of the wall portion 20a.

[0229] In some embodiments, the first limiting portion 32 at least partially overlaps the wall portion 20a in the thickness direction Z of the wall portion 20a.

[0230] The wall portion 20a and the first limiting portion 32 can limit each other in the thickness direction Z, thereby improving the stability of the first electrode terminal 30.

[0231] In some embodiments, at least part of the spacer 40 is located between the wall portion 20a and the first limiting portion 32.

[0232] The spacer 40 can be located entirely between the wall portion 20a and the first limiting portion 32, or can be located only partially between the wall portion 20a and the first limiting portion 32.

[0233] The spacer 40 can be held between the first limiting portion 32 and the wall portion 20a, thereby reducing the risk of direct contact between the first limiting portion 32 and the wall portion 20a when the battery cell 7 is in thermal runaway, thereby suppressing the current between the first electrode terminal 30 and the wall portion 20a and reducing the sustained heat generation of the first electrode terminal 30 and the wall portion 20a.

[0234] In some embodiments, the first limiting portion 32 and the terminal body 31 are integrally formed.

[0235] In some embodiments, the first electrode terminal 30 is riveted to the wall portion 20a. For example, when assembling the wall portion 20a and the first electrode terminal 30, the first electrode terminal 30 can be first inserted through the electrode lead-out hole 2111, and then the end portion of the first electrode terminal 30 is pressed to form a flange structure, which can serve as the first limiting portion 32.

[0236] In some embodiments, the first electrode terminal 30 further includes a second limiting portion 33 connected to the terminal body 31, at least part of the second limiting portion 33 protrudes from the outer peripheral surface of the terminal body 31, and the first limiting portion 32 and the second limiting portion 33 are respectively located on both sides of the wall portion 20a in the thickness direction Z of the wall portion 20a.

[0237] In some examples, the second limiting portion 33 and the terminal body 31 can be integrally formed. In other examples, the second limiting portion 33 and the terminal body 31 are separately formed and connected by welding, riveting, bonding or other means.

[0238] One of the first and second stoppers 32 and 33 is located on the inner side of the wall portion 20a, and the other is located on the outer side of the wall portion 20a.

[0239] The first and second stoppers 32 and 33 can achieve fixation of the first electrode terminal 30 in the thickness direction Z of the wall portion 20a.

[0240] In some embodiments, one of the first and second stoppers 32 and 33 is formed after the first electrode terminal 30 passes through the electrode lead-out hole 2111.

[0241] In some examples, the first stopper 32 is located on the outer side of the wall portion 20a, and the first electrode terminal 30 is riveted to the wall portion 20a from the outer side of the wall portion 20a to form the first stopper 32.

[0242] In some examples, the first stopper 32 is located on the inner side of the wall portion 20a, and the first electrode terminal 30 is riveted to the wall portion 20a from the inner side of the wall portion 20a to form the first stopper 32.

[0243] In some examples, the second stopper 33 is located on the outer side of the wall portion 20a, and the first electrode terminal 30 is riveted to the wall portion 20a from the outer side of the wall portion 20a to form the second stopper 33.

[0244] In some examples, the second stopper 33 is located on the inner side of the wall portion 20a, and the first electrode terminal 30 is riveted to the wall portion 20a from the inner side of the wall portion 20a to form the second stopper 33.

[0245] In some embodiments, the battery cell 7 further includes a seal 60, at least a portion of the seal 60 is disposed between the second stopper 33 and the wall portion 20a in the thickness direction Z.

[0246] The second stopper 33 and the wall portion 20a can clamp the seal 60 in the thickness direction Z to achieve sealing of the electrode lead-out hole 2111.

[0247] In some embodiments, the seal 60 has a melting point greater than or equal to 300°C. As an example, the seal 60 has a melting point of 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, or 1000°C.

[0248] The seal 60 has a high melting point, which is not easy to melt when the battery cell 7 is in thermal runaway, thereby remaining between the second stopper 33 and the wall portion 20a, reducing the risk of direct contact of the first electrode terminal 30 with the wall portion 20a.

[0249] In some embodiments, the seal 60 has electrical insulation. As an example, the seal 60 is made of an insulating material.

[0250] After the battery cell 7 thermal runaway, the seal 60 can inhibit the current between the second limiting portion 33 and the wall portion 20a, reduce the sustained heat generation of the first electrode terminal 30 and the wall portion 20a, reduce the risk of thermal runaway of other battery cells 7, and improve the reliability.

[0251] In some embodiments, the seal 60 is in a compressed state; when the battery cell 7 thermal runaway, even if the local melting of the seal 60, it can fill between the second limiting portion 33 and the wall portion 20a, reduce the risk of direct contact between the second limiting portion 33 and the wall portion 20a.

[0252] In some embodiments, the isolation piece 40 is arranged around the terminal body 31. The seal 60 is arranged around the terminal body 31.

[0253] In some embodiments, the isolation piece 40 includes a first isolation portion 41 and a second isolation portion 42 connected, at least part of the first isolation portion 41 is located between the first limiting portion 32 and the wall portion 20a, and at least part of the second isolation portion 42 is located in the electrode lead-out hole 2111.

[0254] The first isolation portion 41 can isolate the first limiting portion 32 from the wall portion 20a, and the second isolation portion 42 can isolate at least part of the terminal body 31 from the wall portion 20a, thereby reducing the risk of direct contact between the wall portion 20a and the first electrode terminal 30.

[0255] In some embodiments, in the thickness direction Z, the second isolation portion 42 can abut the seal 60. The isolation piece 40 and the seal 60 can jointly separate the wall portion 20a from the first electrode terminal 30.

[0256] In some embodiments, the seal 60 includes a first seal portion 61 and a second seal portion 62 connected, at least part of the first seal portion 61 is located between the second limiting portion 33 and the wall portion 20a, and at least part of the second seal portion 62 is located in the electrode lead-out hole 2111.

[0257] The first seal portion 61 can isolate the second limiting portion 33 from the wall portion 20a, and the second seal portion 62 can isolate at least part of the terminal body 31 from the wall portion 20a, thereby reducing the risk of direct contact between the wall portion 20a and the first electrode terminal 30.

[0258] In some embodiments, in the thickness direction Z, the second seal portion 62 and the second isolation portion 42 abut to completely isolate the terminal body 31 from the hole wall of the electrode lead-out hole 2111.

[0259] In some embodiments, the battery cell 7 further includes a first insulating piece 70, at least part of the first insulating piece 70 is arranged between the first electrode terminal 30 and the wall portion 20a.

[0260] When the battery cell 7 is working normally, the first insulating member 70 can insulate the first electrode terminal 30 from the wall portion 20a to reduce the risk of short circuit of the battery cell 7. When the battery cell 7 is thermal runaway, even if the first insulating member 70 melts at high temperature, the spacer 40 can be kept between the first electrode terminal 30 and the wall portion 20a to inhibit the current between the first electrode terminal 30 and the wall portion 20a.

[0261] In some embodiments, the melting point of the spacer 40 is higher than the melting point of the first insulating member 70.

[0262] The spacer 40 has a higher melting point, and when the battery cell 7 is thermal runaway, even if the first insulating member 70 melts at high temperature, the spacer 40 can be kept between the first electrode terminal 30 and the wall portion 20a to inhibit the current between the first electrode terminal 30 and the wall portion 20a.

[0263] In some embodiments, the material of the first insulating member 70 is plastic. Exemplarily, the material of the first insulating member 70 is PFA (polytetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer).

[0264] In some embodiments, at least part of the first insulating member 70 is arranged between the first limiting portion 32 and the wall portion 20a.

[0265] In some embodiments, the first insulating member 70 is arranged around the terminal body 31.

[0266] In some embodiments, the first insulating member 70 includes a first insulating portion 71 and a second insulating portion 72, at least part of the first insulating portion 71 is arranged between the wall portion 20a and the first limiting portion 32, and at least part of the second insulating portion 72 is arranged in the electrode lead-out hole 2111 and located between the hole wall of the electrode lead-out hole 2111 and the terminal body 31.

[0267] In some embodiments, in the thickness direction Z, the second insulating portion 72 abuts against the second sealing portion 62.

[0268] In some embodiments, the battery cell 7 further includes a second insulating member 80, and in the thickness direction Z, at least part of the second insulating member 80 is arranged between the second limiting portion 33 and the wall portion 20a.

[0269] When the battery cell 7 is working normally, the second insulating member 80 can separate the second limiting portion 33 from the wall portion 20a to reduce the risk of short circuit of the battery cell 7. When the battery cell 7 is thermal runaway, even if the second insulating member 80 melts at high temperature, the sealing member 60 can be kept between the second limiting portion 33 and the wall portion 20a to reduce the risk of contact between the second limiting portion 33 and the wall portion 20a, and inhibit the current between the first electrode terminal 30 and the wall portion 20a.

[0270] In some embodiments, the second insulating member 80 is made of plastic.

[0271] In some embodiments, the second insulating member 80 is disposed around the terminal body 31.

[0272] In some embodiments, the isolation member 40 is formed on at least one surface of the first electrode terminal 30, the wall portion 20a, and the first insulating member 70.

[0273] For example, the isolation member 40 can be formed on the surface of the first electrode terminal 30, the wall portion 20a, or the first insulating member 70 by coating, pasting, or other means.

[0274] In some embodiments, the isolation member 40 is pasted on the surface of one of the first electrode terminal 30, the wall portion 20a, and the first insulating member 70.

[0275] The following describes a method for measuring the resistance value of the isolation member 40, taking the case where the isolation member 40 is pasted on the wall portion 20a as an example:

[0276] Peel the isolation member from the wall portion;

[0277] At room temperature, connect the positive and negative probes of the resistance meter to the two surfaces of the isolation member in the thickness direction, and measure the resistance value;

[0278] Measure the resistance value at multiple positions on the isolation member, and the minimum resistance value measured can be the resistance value of the isolation member.

[0279] The case where the isolation member 40 is pasted on the first electrode terminal 30 or the first insulating member 70 can also be measured in the above-described manner. In some embodiments, the isolation member 40 is coated on the surface of one of the first electrode terminal 30, the wall portion 20a, and the first insulating member 70.

[0280] The following describes a method for measuring the resistance value of the isolation member 40, taking the case where the isolation member 40 is coated on the wall portion 20a as an example:

[0281] At room temperature, connect the positive probe (or the negative probe) of the resistance meter to the wall portion, and connect the negative probe (or the positive probe) of the resistance meter to the surface of the isolation member facing away from the wall portion, and measure the resistance value;

[0282] Move the negative probe and measure the resistance value at multiple positions on the surface of the isolation member facing away from the wall portion, and the minimum resistance value measured can be the resistance value of the isolation member.

[0283] It is noted that the wall portion is an electrically conductive structure, and the resistance of the wall portion can be ignored compared to the resistance of the isolation member, so the positive probe can be connected to the wall portion 20a for measurement.

[0284] The scheme in which the insulating member 40 is applied to the first electrode terminal 30 or the first insulating member 70 can also be measured in the above-described manner.

[0285] In some embodiments, the insulating member 40 is formed on surfaces of at least two of the first electrode terminal 30, the wall portion 20a, and the first insulating member 70.

[0286] In some embodiments, the insulating member 40 is formed on surfaces of all of the first electrode terminal 30, the wall portion 20a, and the first insulating member 70.

[0287] In some embodiments, the insulating member 40 is formed on a surface of the wall portion 20a.

[0288] In some embodiments, the wall portion 20a includes a first surface 2112 and a second surface 2113 arranged in the thickness direction Z, the first surface 2112 facing the first positioning portion 32, and the second surface 2113 facing the second positioning portion 33. A hole wall surface of the electrode lead-out hole 2111 connects the first surface 2112 and the second surface 2113.

[0289] In some embodiments, the first insulating portion 41 is attached to the first surface 2112, and the second insulating portion 42 is attached to the second surface 2113.

[0290] In some embodiments, the wall portion 20a includes a first recessed portion 2114 on a side facing the first positioning portion 32. The electrode lead-out hole 2111 is arranged on a bottom wall of the first recessed portion 2114.

[0291] In some embodiments, the first insulating portion 41 is attached to at least a bottom surface of the first recessed portion 2114. Optionally, the first insulating portion 41 is entirely accommodated in the first recessed portion 2114 to save space occupied by the first insulating portion 41.

[0292] In some embodiments, in the thickness direction Z, a thickness of the first insulating portion 41 is smaller than a depth of the first recessed portion 2114.

[0293] In some embodiments, the first insulating portion 41 is further attached to a side surface of the first recessed portion 2114. The first surface 2112 defines the first recessed portion 2114, i.e., the first surface 2112 includes a bottom surface of the first recessed portion 2114 and a side surface of the first recessed portion 2114.

[0294] In some embodiments, the first surface 2112 further includes a surrounding planar region, the planar region is connected to the side surface of the first recessed portion 2114, and the first recessed portion 2114 is recessed with respect to the planar region.

[0295] In some embodiments, the first insulating portion 41 is further attached to the planar region.

[0296] In some embodiments, the electrode assembly 10 further includes a second tab 10b opposite in polarity to the first tab 10a, and the second tab 10b is electrically connected to the wall portion 20a.

[0297] In some examples, the spacer 40 has electrical insulation, which can insulate the wall portion 20a from the first electrode terminal 30 when the battery cell is normally working, reducing the risk of short circuit. In other examples, other insulation structures, such as the first insulating member 70, are provided between the wall portion 20a and the first electrode terminal 30, which can insulate the wall portion 20a from the first electrode terminal 30 when the battery cell is normally working, reducing the risk of short circuit.

[0298] The wall portion 20a and the first electrode terminal 30 can serve as two electrodes of the battery cell 7 and are located on the same side of the battery cell 7. When a plurality of battery cells 7 are assembled into a group, the connection of the busbar member to the wall portion 20a or the connection of the busbar member to the first electrode terminal 30 is facilitated, and the structure of the battery device is simplified. Although the wall portion 20a and the first electrode terminal 30 are opposite in polarity, the spacer 40 can inhibit the current between the wall portion 20a and the first electrode terminal 30 when the battery cell 7 is in thermal runaway, reducing the sustained heat generation of the first electrode terminal 30 and the wall portion 20a, and improving reliability.

[0299] In some embodiments, the electrode assembly 10 includes a positive electrode sheet 11, the positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode film layer 112 disposed on at least one side of the positive electrode current collector 111, and the positive electrode film layer 112 includes a positive electrode active material, and the positive electrode active material includes a layered transition metal oxide.

[0300] The layered transition metal oxide includes at least one of a compound of a chemical formula Li a Ni b Co c M d O e A f , 0.8≤a≤1.2, 0.8≤b≤0.95, 0

[0301] As an example, b is 0.8, 0.82, 0.84, 0.85, 0.88, 0.9, 0.92, 0.94, or 0.95.

[0302] As an example, examples of the layered transition metal oxide can include, but are not limited to, LiNi 0.8 Co 0.1 Mn 0.1 O2(also referred to as NCM811 LiNi 0.9 Co 0.05 Mn 0.05 O2(also referred to as Ni 90 LiNi 0.80 Co 0.15 Al 0.05 O2) and modified compounds thereof.

[0303] The battery cell 7 with high nickel content has the advantages of high energy density, good low-temperature performance, and good charge-discharge performance.

[0304] Specifically, the positive electrode film layer 112 has high nickel content, which can store more electrical energy, thereby significantly improving the energy density of the battery cell 7. With the increase of nickel content, the use amount of cobalt, which is a scarce and expensive metal, is relatively reduced, and the use of cobalt can reduce the cost of the battery cell 7. The battery cell 7 with high nickel content has high electrical conductivity, which means that the battery cell 7 can operate at a higher power, supporting fast charging and large current discharging. In a low-temperature environment, the capacity attenuation of the battery cell 7 with high nickel content is relatively small, which can maintain a high discharge efficiency, so that the electrical equipment can be used normally in a low-temperature environment.

[0305] However, the thermal stability of the battery cell 7 with high nickel content is relatively poor, and when it is in thermal runaway, the heat generated is more, and the temperature rise of the battery cell 7 is higher. The present application sets a high-temperature-resistant isolation piece 40 between the wall portion 20a and the first electrode terminal 30, which can withstand the high temperature generated by the high-nickel battery cell 7 in thermal runaway, thereby inhibiting the current between the first electrode terminal 30 and the wall portion 20a, and reducing the continuous heat generation of the first electrode terminal 30 and the wall portion 20a.

[0306] In the present application, b is set to be less than or equal to 0.95, which can reduce the maximum temperature of the battery cell 7 in thermal runaway, and reduce the risk of melting failure of the isolation piece 40 due to excessive temperature.

[0307] In some embodiments, 0.8≤b≤0.95, and optionally, 0.85≤b≤0.90.

[0308] In some embodiments, the battery cell 7 further includes an electrolyte contained in the shell 20. The electrolyte includes a chain ester solvent, and the mass percentage content of the chain ester solvent in the electrolyte is 25.5wt% to 76.5wt%.

[0309] Exemplarily, the mass percentage content of the chain ester solvent in the electrolyte is 25.5 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 32 wt%, 35 wt%, 38 wt%, 40 wt%, 42 wt%, 45 wt%, 48 wt%, 50 wt%, 52 wt%, 55 wt%, 58 wt%, 60 wt%, 62 wt%, 65 wt%, 68 wt%, 70 wt%, 72 wt%, 75 wt%, 76.5 wt%, or a range formed by any two of the above values.

[0310] In the embodiments of the present application, the mass percentage content of the chain ester solvent is greater than or equal to 25.5 wt%, so that the conductivity of the electrolyte is relatively high, which is beneficial to improving the liquid-phase transmission capacity of active ions and the rapid charging and discharging capacity of the battery cell 7, thereby improving the rate performance of the battery cell 7. The mass percentage content of the chain ester solvent being greater than or equal to 25.5 wt% can also make the viscosity of the electrolyte system relatively low, which is more conducive to the infiltration of the flow electrode assembly 10, thereby improving the rapid charging and discharging capacity of the battery cell 7, and further improving the rate performance of the battery cell 7.

[0311] The chain ester solvent may face the problem of decomposition and gas production during the cycle charging and discharging of the battery cell 7. In the embodiments of the present application, the mass percentage content of the chain ester solvent is set to be less than or equal to 76.5 wt%, which can limit the internal pressure of the battery cell 7, reduce the deformation of the shell 20, reduce the risk of failure of the battery cell 7, and improve the reliability.

[0312] In some embodiments, the mass percentage content of the chain ester solvent in the electrolyte is 42.5 wt% to 70 wt%, which can further take into account the rate performance and use reliability of the battery cell 7, and improve the cycle performance of the battery cell 7.

[0313] In some embodiments, the chain ester solvent includes at least one of a chain carbonate and a chain carboxylic acid ester.

[0314] In some embodiments, the chain ester solvent includes a chain carbonate and a chain carboxylic acid ester. The combination of the chain carboxylic acid ester and the chain carbonate can improve the conductivity of the electrolyte, improve the liquid-phase transmission kinetics of the electrolyte, and further improve the rate performance and use reliability of the battery cell 7.

[0315] In some embodiments, the thermal conductivity coefficient of the partition 40 is less than the thermal conductivity coefficient of the wall portion 20a, and the thermal conductivity coefficient of the partition 40 is less than the thermal conductivity coefficient of the first electrode terminal 30.

[0316] Compared with the wall portion 20a and the first electrode terminal 30, the isolation member 40 has a smaller thermal conductivity, and the isolation member 40 can slow down the heat conduction when the battery cell 7 is in thermal runaway, reduce the temperature rise of the isolation member 40, and reduce the risk of melting failure of the isolation member 40.

[0317] In some embodiments, the wall portion 20a has a thermal conductivity smaller than that of the first electrode terminal 30. When the battery cell 7 is in thermal runaway, the wall portion 20a has a large heat receiving area and is prone to heat up. The wall portion 20a has a smaller thermal conductivity, which can reduce the heat conduction from the wall portion 20a to the isolation member 40, thereby reducing the temperature rise of the isolation member 40 and reducing the risk of melting failure of the isolation member 40.

[0318] In some embodiments, the wall portion 20a has a thermal conductivity smaller than or equal to 100 W / (m·K).

[0319] In some embodiments, the material of the wall portion 20a is steel. The material of the first electrode terminal 30 is aluminum or aluminum alloy.

[0320] In some embodiments, the shell 20 includes a housing 21 and an end cover 22, the housing 21 includes a side wall 212 and an end wall 211, the side wall 212 surrounds the electrode assembly 10, and the end wall 211 and the end cover 22 are opposite to each other, and the end cover 22 is sealingly connected to the side wall 212. The wall portion 20a is the end cover 22 or the end wall 211.

[0321] In some embodiments, the side wall 212 and the end wall 211 can be integrally formed. In other examples, the side wall 212 and the end wall 211 can also be independently formed and connected as a whole by bonding, clamping, welding or other means.

[0322] The end cover 22 can be insulated from the side wall 212 or electrically connected.

[0323] The housing 21 has an opening at an end away from the end wall 211, and the end cover 22 covers the opening of the housing 21.

[0324] In some embodiments, the side wall 212 and the end wall 211 are integrally formed to improve the strength of the housing 21.

[0325] In some examples, the battery cell 7 is a cylindrical battery cell, and the side wall 212 is a cylindrical structure.

[0326] In another example, the battery cell 7 is a square shell battery cell, and the side wall 212 is a square cylindrical structure.

[0327] In some embodiments, the material of the side wall 212 includes steel. The thickness of the side wall 212 is 0.3 mm to 1.5 mm.

[0328] For example, the thickness of the side wall 212 is 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.35 mm, 0.38 mm, 0.40 mm, 0.42 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, or 1.5 mm.

[0329] In the embodiments of the present application, the thickness of the side wall 212 is in the meaning known in the art and can be detected by using devices and methods known in the art, for example, a micrometer or a vernier caliper.

[0330] For example, the material of the side wall 212 includes stainless steel.

[0331] The mechanical strength of the side wall 212 is relatively high and is not easy to deform, which is more conducive to improving the energy density of the battery monomer 7 while making the battery monomer 7 have excellent use reliability when used with the silicon-containing negative electrode sheet 12.

[0332] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 1.2 mm.

[0333] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 0.9 mm, which can be 0.3 mm to 0.6 mm.

[0334] In some embodiments, the material of the wall portion 20a is the same as that of the side wall 212.

[0335] In some embodiments, the material of the end cover 22 is steel.

[0336] In some embodiments, the battery monomer 7 is a cylindrical battery monomer. The cylindrical battery monomer has the advantages of mature production process, good consistency, good heat dissipation performance, and high grouping efficiency.

[0337] In some embodiments, the diameter of the cylindrical battery monomer is greater than or equal to 35 mm and less than or equal to 70 mm.

[0338] For example, the diameter of the cylindrical battery monomer is 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, or 70 mm.

[0339] The diameter of the cylindrical battery cell is greater than or equal to 35 mm, which can improve the capacity and energy density of the cylindrical battery cell. The diameter of the cylindrical battery cell is related to the heat generation of the cylindrical battery cell in thermal runaway. The diameter of the cylindrical battery cell is less than or equal to 70 mm to limit the maximum temperature of the cylindrical battery cell in thermal runaway and reduce the risk of melting failure of the separator 40.

[0340] Optionally, the diameter of the cylindrical battery cell is 45 mm to 60 mm.

[0341] In some embodiments, the height of the shell 20 is 50 mm to 150 mm. For example, the height of the shell 20 is 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, or 150 mm.

[0342] Optionally, the height of the shell 20 is 60 mm to 100 mm.

[0343] In some embodiments, the height of the shell 20 is 1.3 times to 4 times the diameter of the shell 20. For example, the height of the shell 20 can be the axial dimension of the shell 20 along the cylindrical battery cell.

[0344] Optionally, the height of the shell 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, or 4.0 times the diameter of the shell 20.

[0345] When the shell 20 meets the above size requirements, the structural stability of the shell 20 is high, which can improve the use reliability of the cylindrical battery cell.

[0346] In some embodiments, the height of the shell 20 is 1.5 times to 2.5 times the diameter of the shell 20.

[0347] In some embodiments, the wall portion 20a is an end wall 211. Optionally, the second tab 10b is electrically connected to the end wall 211. The second tab 10b can be directly connected to the end wall 211, or indirectly connected to the end wall 211 through the end cover 22, the side wall 212, or other components.

[0348] In some embodiments, the first tab 10a is located at an end of the electrode assembly 10 facing the end wall 211, and the second tab 10b is located at an end of the electrode assembly 10 facing the end cover 22.

[0349] FIG. 13 is a partial cross-sectional view of a battery cell according to some embodiments of the present application; and FIG. 14 is an enlarged view of the box in FIG. 13.

[0350] Referring to FIGS. 13 and 14, in some embodiments, a portion of the seal 60 and a portion of the spacer 40 are stacked in the thickness direction Z, thereby improving the isolation effect and reducing the risk of the first electrode terminal 30 contacting the wall portion 20a when the battery cell 7 is in thermal runaway.

[0351] In some embodiments, the second spacer portion 42 and the second seal portion 62 at least partially overlap in the electrode lead-out hole 2111 in the radial direction of the electrode lead-out hole 2111.

[0352] The second spacer portion 42 and the second seal portion 62 can have a double isolation effect in the radial direction of the electrode lead-out hole 2111, thereby reducing the risk of the first electrode terminal 30 contacting the wall portion 20a when the battery cell 7 is in thermal runaway.

[0353] In some embodiments, the spacer 40 further includes a third spacer portion 43. In the thickness direction Z, a portion of the third spacer portion 43 is stacked between the wall portion 20a and the second limiting portion 33 with a portion of the first seal portion 61.

[0354] In some embodiments, the third spacer portion 43 is connected to the second spacer portion 42 toward an end of the terminal body 31.

[0355] In some embodiments, the third spacer portion 43 is attached to the second surface 2113. At least a portion of the first seal portion 61 is clamped between the third spacer portion 43 and the second limiting portion 33.

[0356] In some embodiments, in a direction of the terminal body 31 pointing to the second limiting portion 33, the third spacer portion 43 protrudes from the end of the second limiting portion 33 away from the terminal body 31. The third spacer portion 43 can isolate the second limiting portion 33 from the wall portion 20a.

[0357] In some embodiments, in the thickness direction Z, the third spacer portion 43 covers the outer end of the first seal portion 61 away from the terminal body 31 and the inner end of the second insulating member 80 close to the terminal body 31.

[0358] In some embodiments, in the thickness direction Z, the first seal portion 61 partially overlaps the second insulating member 80.

[0359] In some embodiments, the first isolation portion 41 is formed independently from the third isolation portion 43. Alternatively, one of the first isolation portion 41 and the third isolation portion 43 is formed integrally with the second isolation portion 42.

[0360] FIG. 15 is a partial cross-sectional view of a battery cell according to some embodiments of the present application; FIG. 16 is an enlarged view of the box in FIG. 15; and FIG. 17 is an enlarged view of the box in FIG. 16.

[0361] Referring to FIGS. 15 to 17, in some embodiments, the isolation member 40 is attached to a surface of the first electrode terminal 30.

[0362] In some embodiments, the first isolation portion 41 is attached to a surface of the first limiting portion 32.

[0363] Alternatively, a portion of the first isolation portion 41 is attached to a surface of the first limiting portion 32 facing the wall portion 20a, and another portion of the first isolation portion 41 is attached to an outer circumferential surface of the first limiting portion 32.

[0364] In some embodiments, the second isolation portion 42 is attached to an outer circumferential surface of the terminal body 31.

[0365] In some embodiments, the third isolation portion 43 is attached to a surface of the second limiting portion 33.

[0366] Alternatively, a portion of the third isolation portion 43 is attached to a surface of the second limiting portion 33 facing the wall portion 20a, and another portion of the third isolation portion 43 is attached to an outer circumferential surface of the second limiting portion 33.

[0367] In some embodiments, the isolation member 40 can be an oxide film or an insulating film.

[0368] FIG. 18 is a partial cross-sectional view of a battery cell according to some other embodiments of the present application; and FIG. 19 is an enlarged view of the box in FIG. 18.

[0369] Referring to FIGS. 18 and 19, in some embodiments, at least a portion of the isolation member 40 is embedded in the first insulating member 70.

[0370] Alternatively, the entire isolation member 40 is embedded in the first insulating member 70.

[0371] Alternatively, the isolation member 40 includes a ceramic layer made of aluminum oxide, titanium oxide, silicon oxide, zirconium oxide, or glass.

[0372] FIG. 20 is a partial cross-sectional view of a battery cell according to some other embodiments of the present application; and FIG. 21 is an enlarged view of the box in FIG. 20.

[0373] Referring to FIGS. 20 and 21, in some embodiments, the spacer 40 includes a first ceramic member 40a. At least a portion of the first ceramic member 40a is disposed between the first electrode terminal 30 and the wall portion 20a. For example, at least a portion of the first ceramic member 40a is disposed between the first limiting portion 32 and the wall portion 20a.

[0374] As an example, the first ceramic member 40a can be composed of alumina, titania, silica, zirconia, glass, or the like.

[0375] In the event of thermal runaway of the battery cell 7, even if the first insulating member 70 melts, the first ceramic member 40a can insulate the first limiting portion 32 from the wall portion 20a.

[0376] As an example, the first ceramic member 40a can be detached, and the positive and negative probes of an ohmmeter can be connected to the surface of the first ceramic member 40a facing the first limiting portion 32 and the surface of the first ceramic member 40a facing the wall portion 20a, respectively, to measure the resistance value of the first ceramic member 40a. The minimum resistance value measured at a plurality of positions on each surface can be taken as the resistance value of the spacer 40.

[0377] In some embodiments, in the thickness direction Z, the first ceramic member 40a at least partially overlaps the first insulating member 70.

[0378] In some embodiments, in the thickness direction Z, at least a portion of the first ceramic member 40a is disposed between the first insulating member 70 and the wall portion 20a.

[0379] In some embodiments, the first ceramic member 40a is annular. The first ceramic member 40a is disposed around the terminal body 31.

[0380] In other embodiments, the first ceramic member 40a is a plurality of first ceramic members 40a, which are spaced apart along the circumference of the terminal body 31. For example, the first ceramic member 40a is a ceramic column.

[0381] In some embodiments, the first insulating member 70 is provided with a second recess 73, and at least a portion of the first ceramic member 40a is accommodated in the second recess 73.

[0382] FIG. 22 is a partial cross-sectional view of a battery cell according to other embodiments of the present application; and FIG. 23 is an enlarged view of the boxed portion of FIG. 22.

[0383] In some embodiments, the spacer 40 includes a second ceramic member 40b. At least a portion of the second ceramic member 40b is disposed between the first electrode terminal 30 and the wall portion 20a. For example, at least a portion of the second ceramic member 40b is disposed between the second limiting portion 33 and the wall portion 20a.

[0384] As an example, the second ceramic member 40b can be composed of alumina, titania, silica, zirconia, glass, or the like.

[0385] When the battery cell 7 is in thermal runaway, even if the second insulating member 80 melts, the second ceramic member 40b can insulate and separate the second limiting portion 33 from the wall portion 20a.

[0386] As an example, the second ceramic member 40b can be detached, and the positive and negative probes of an ohmmeter can be connected to the surface of the second ceramic member 40b facing the second limiting portion 33 and the surface of the second ceramic member 40b facing the wall portion 20a, respectively, to measure the resistance value of the second ceramic member 40b. The minimum resistance value measured at multiple positions on each surface can be taken as the resistance value of the insulating member 40.

[0387] In some embodiments, in the thickness direction Z, the second ceramic member 40b at least partially overlaps the second insulating member 80.

[0388] In some embodiments, in the thickness direction Z, at least part of the second ceramic member 40b is disposed between the second insulating member 80 and the second limiting portion 33.

[0389] In some embodiments, the second ceramic member 40b is annular. The second ceramic member 40b is disposed around the terminal body 31.

[0390] In other embodiments, the second ceramic member 40b is a plurality of second ceramic members 40b, which are spaced apart along the circumference of the terminal body 31. For example, the second ceramic member 40b is a ceramic column.

[0391] In some embodiments, the second insulating member 80 is provided with a third recess 80a on the side facing the second limiting portion 33, and the second limiting portion 33 is provided with a fourth recess 331 on the side facing the second insulating member 80, and a part of the second ceramic member 40b is accommodated in the third recess 80a, and another part is accommodated in the fourth recess 331.

[0392] The third recess 80a and the fourth recess 331 can position the second ceramic member 40b.

[0393] FIG. 24 is a partial cross-sectional view of a battery cell according to some embodiments of the present application.

[0394] Referring to FIG. 24, in some embodiments, the first insulating member 70 can be omitted. Alternatively, the insulating member 40 can have electrical insulation, and the insulating member 40 can both function as insulation when the battery cell 7 is in normal operation and maintain the isolation state between the first electrode terminal 30 and the wall portion 20a when the battery cell 7 is in thermal runaway.

[0395] In some embodiments, the second insulating member 80 and the spacer 40 can be made of the same material to improve the high-temperature resistance of the second insulating member 80.

[0396] In some other embodiments, the first insulating member can contain high-temperature resistant materials such as ceramic particles or ceramic fibers. For example, the first insulating member can be a multi-layer structure, for example, the first insulating member contains ceramic particles or ceramic fibers in the central layer and does not contain ceramic particles or ceramic fibers in the two outer surface layers. The first insulating member contains ceramic particles or ceramic fibers, which can inhibit the current between the electrode terminal and the wall portion when the battery cell is in thermal runaway, so that the spacer can be omitted.

[0397] FIG. 25 is a partial cross-sectional view of a battery cell according to some other embodiments of the present application.

[0398] In some embodiments, the first tab 10a and the second tab 10b are both located at one end of the electrode assembly 10 facing the wall portion 20a. The first tab 10a and the second tab 10b can share space in the thickness direction Z of the wall portion 20a, thereby improving space utilization and increasing energy density.

[0399] In some embodiments, the battery cell 7 further includes a second electrode terminal 90 electrically connected to the second tab 10b.

[0400] In some embodiments, the first electrode terminal 30 and the second electrode terminal 90 are both provided on the wall portion 20a.

[0401] The second electrode terminal 90 can be electrically connected to the wall portion 20a or insulated from the wall portion 20a.

[0402] As an example, the battery cell 7 further includes a third insulating member 50, at least a portion of the third insulating member 50 is provided between the wall portion 20a and the second electrode terminal 90 to insulate the wall portion 20a from the second electrode terminal 90.

[0403] When the battery cell 7 is in thermal runaway due to internal short circuit or other reasons, the battery cell 7 can maintain a high temperature state for a period of time. If the third insulating member 50 melts, the wall portion 20a can come into contact with the second electrode terminal 90; the spacer 40 is not easy to melt at a high temperature, and it can be kept between the first electrode terminal 30 and the wall portion 20a, thereby reducing the risk of direct contact between the first electrode terminal 30 and the wall portion 20a; even if the first electrode terminal 30, the spacer 40, the wall portion 20a, and the second electrode terminal 90 form a loop with other battery cells, the spacer 40 can inhibit the current transmitted between the first electrode terminal 30, the spacer 40, the wall portion 20a, and the second electrode terminal 90, reduce the continuous heat generation, reduce the thermal impact on other battery cells in the surrounding, and reduce the risk of thermal runaway of other battery cells 7, thereby improving the reliability.

[0404] In some embodiments, the second electrode terminal 90 and the wall portion 20a can be provided with the isolation member 40 or can not be provided with the isolation member 40. Optionally, the second electrode terminal 90 and the wall portion 20a are also provided with the high-temperature-resistant isolation member.

[0405] In other embodiments, the second electrode terminal 90 can be omitted, and the second tab 10b can be connected to the wall portion 20a.

[0406] In some embodiments, the battery cell 7 is a cylindrical battery cell.

[0407] FIG. 26 is an exploded schematic view of a battery cell according to some embodiments of the present application; and FIG. 27 is a partial cross-sectional schematic view of a battery cell according to some embodiments of the present application.

[0408] Referring to FIGS. 26 and 27, in some embodiments, the battery cell 7 is a prismatic battery cell.

[0409] In some embodiments, the first electrode terminal 30 and the second electrode terminal 90 are both provided with the end cap 22.

[0410] In some embodiments, the second limiting portion 33 is integrally formed with the terminal body 31, and the first limiting portion 32 is riveted to the terminal body 31.

[0411] In some embodiments, the second electrode terminal 90 and the end cap 22 can not be provided with the isolation member 40. The second electrode terminal 90 and the end cap 22 can be insulated or electrically connected.

[0412] FIG. 28 is a simplified schematic view of a battery device according to some embodiments of the present application.

[0413] Referring to FIG. 28, the present application also provides a battery device 2 comprising a plurality of battery cells 7 according to any of the above embodiments.

[0414] In some embodiments, the battery device 2 further comprises a plurality of busbar components 8 electrically connecting the plurality of battery cells 7.

[0415] In some embodiments, at least two battery cells 7 are connected in parallel.

[0416] For example, at least two battery cells 7 are connected in parallel and form a battery unit 7a, and a plurality of battery cells 7 are connected in series. The plurality of battery cells 7 of the battery device 2 form a multi-parallel and series connection structure. The multi-parallel and series connection structure can improve reliability. When a certain battery cell 7 fails due to an accident (e.g., thermal runaway), the battery cells 7 connected in parallel with the battery cell 7 can still work normally, reducing the risk of complete failure of the entire circuit.

[0417] When one of the battery cells 7 is in thermal runaway, the normal battery cell 7 connected in parallel with the battery cell 7 in thermal runaway can be electrically connected to the wall portion 20a and the first electrode terminal 30 of the battery cell 7 in thermal runaway, respectively, and the isolation member 40 has a large resistance, which can inhibit the current flowing through the normal battery cell 7, reduce the risk of abnormality of the normal battery cell 7, and affect the reliability.

[0418] According to some embodiments of the present application, the present application also provides a battery cell 7 as any of the above embodiments. The battery cell 7 is used to provide power for an electrical device. The electrical device can be any of the devices or systems as described above.

[0419] Referring to FIGS. 4-12, the present application provides a cylindrical battery cell, which includes a housing 20, a first electrode terminal 30, an electrode assembly 10, an isolation member 40, a first insulation member 70, a second insulation member 80, and a sealing member 60.

[0420] The housing 20 includes a shell 21 and an end cover 22. The shell 21 includes an integrally formed side wall 212 and an end wall 211. The side wall 212 surrounds the electrode assembly 10. The end wall 211 is opposite to the end cover 22. The end cover 22 is sealingly connected to the side wall 212.

[0421] The electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 includes a first tab 10a and a second tab 10b. The first tab 10a is electrically connected to the first electrode terminal 30. The second tab 10b is electrically connected to the end wall 211.

[0422] The end wall 211 is provided with an electrode lead-out hole 2111. The first electrode terminal 30 includes a terminal body 31, a first limiting portion 32, and a second limiting portion 33. At least a portion of the terminal body 31 is accommodated in the electrode lead-out hole 2111. The first limiting portion 32 is connected to the terminal body 31. At least a portion of the first limiting portion 32 protrudes from the outer peripheral surface of the terminal body 31. The second limiting portion 33 is connected to the terminal body 31. At least a portion of the second limiting portion 33 protrudes from the outer peripheral surface of the terminal body 31. In the thickness direction Z of the end wall 211, the first limiting portion 32 and the second limiting portion 33 are located on both sides of the end wall 211, respectively.

[0423] The first insulation member 70 surrounds the terminal body 31. At least a portion of the first insulation member 70 is arranged between the first limiting portion 32 and the end wall 211. The sealing member 60 surrounds the terminal body 31. At least a portion of the sealing member 60 is arranged between the second limiting portion 33 and the end wall 211. At least a portion of the second insulation member 80 surrounds the outside of the sealing member 60 and is arranged between the second limiting portion 33 and the end wall 211.

[0424] The isolation piece 40 is attached to the surface of the end wall 211. At least part of the isolation piece 40 is arranged between the first electrode terminal 30 and the end wall 211. Optionally, the isolation piece 40 is bonded to the surface of the end wall 211. Optionally, at least part of the isolation piece 40 is located between the first insulation piece 70 and the end wall 211.

[0425] The resistance value of the isolation piece 40 is greater than or equal to 1Ω, and the melting point of the isolation piece 40 is greater than or equal to 450°.

[0426] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0427] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, comprising: a housing including a wall portion; a first electrode terminal provided to the wall portion; an electrode assembly accommodated in the housing, the electrode assembly including a first tab electrically connected to the first electrode terminal; and a separator at least partially provided between the first electrode terminal and the wall portion, the separator having an electrical resistance value greater than or equal to 1 Ω and a melting point greater than or equal to 450°. The separator has an electrical resistance value greater than or equal to 5 Ω.

2. The battery cell of claim 1, wherein, The separator has an electrical resistivity greater than or equal to 50,000 Ω·cm.

3. The battery cell of claim 1 or 2, wherein, The separator insulates the first electrode terminal from the wall portion.

4. The battery cell of any one of claims 1-3, wherein, 5.The battery cell according to any one of claims 1 to 4, wherein the wall portion is provided with an electrode lead-out hole; the first electrode terminal includes a terminal body and a first stopper portion, at least a portion of the terminal body is accommodated in the electrode lead-out hole, the first stopper portion is connected to the terminal body, and at least a portion of the first stopper portion protrudes from an outer circumferential surface of the terminal body; in a thickness direction of the wall portion, the first stopper portion at least partially overlaps the wall portion, and at least a portion of the separator is positioned between the wall portion and the first stopper portion. The first electrode terminal further includes a second stopper portion connected to the terminal body, at least a portion of the second stopper portion protrudes from the outer circumferential surface of the terminal body, and in the thickness direction of the wall portion, the first stopper portion and the second stopper portion are respectively positioned on both sides of the wall portion; 6. The battery cell of claim 5, wherein, the battery cell further includes a seal, and in the thickness direction, at least a portion of the seal is provided between the second stopper portion and the wall portion; the seal has a melting point greater than or equal to 300°. In the thickness direction, a portion of the seal and a portion of the separator are stacked.

7. The battery cell of claim 6, wherein, The seal includes a first seal portion and a second seal portion connected to each other, at least a portion of the first seal portion is positioned between the second stopper portion and the wall portion, and at least a portion of the second seal portion is positioned in the electrode lead-out hole; 8. The battery cell of claim 6 or 7, wherein, The separator includes a first separator portion and a second separator portion connected to each other, at least a portion of the first separator portion is positioned between the first stopper portion and the wall portion, and at least a portion of the second separator portion is positioned in the electrode lead-out hole, and in a radial direction of the electrode lead-out hole, the second separator portion and the second seal portion at least partially overlap in the electrode lead-out hole. The battery cell further includes a first insulator, and at least a portion of the first insulator is provided between the first electrode terminal and the wall portion.

9. The battery cell of any one of claims 1-8, wherein, The melting point of the separator is higher than the melting point of the first insulator.

10. The battery cell of claim 9, wherein, The separator is formed at least on a surface of one of the first electrode terminal, the wall portion, and the first insulator.

11. The battery cell of claim 9 or 10, wherein, The electrode assembly further includes a second tab having a polarity opposite to that of the first tab, and the second tab is electrically connected to the wall portion.

12. The battery cell of any one of claims 4, 9-11, wherein, The material of the separator includes at least one of an organic substance, an inorganic metal oxide, and an inorganic non-metallic material.

13. The battery cell of any one of claims 1-12, wherein, ​ 14. The battery cell of any one of claims 1-13, wherein, The electrode assembly comprises a positive electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises a layered transition metal oxide; The layered transition metal oxide includes at least one of a compound of a chemical formula of Li a Ni b Co c M d O e A f a compound modified therefrom, 0.8≤a≤1.2, 0.8≤b≤0.95, 0 M includes at least one of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes at least one of N, F, S, and Cl.

15. The battery cell of any one of claims 1-14, further comprising an electrolyte contained within the housing. The electrolyte comprises a chain ester solvent, a mass percentage content of the chain ester solvent in the electrolyte is 25.5wt% to 76.5wt%.

16. The battery cell of claim 15, wherein, The mass percentage content of the chain ester solvent in the electrolyte is 42.5wt% to 70wt%.

17. The battery cell of any one of claims 1-16, wherein, The thermal conductivity of the isolation piece is less than the thermal conductivity of the wall portion, and the thermal conductivity of the isolation piece is less than the thermal conductivity of the first electrode terminal.

18. The battery cell of claim 17, wherein, The thermal conductivity of the wall portion is less than the thermal conductivity of the first electrode terminal.

19. The battery cell of any one of claims 1-18, wherein, The housing comprises a shell and an end cover, the shell comprises a side wall and an end wall, the side wall surrounds the electrode assembly, the end wall and the end cover are opposite, and the end cover is sealingly connected to the side wall. The wall portion is the end cover or the end wall.

20. The battery cell of claim 19, wherein, The side wall and the end wall are integrally formed.

21. The battery cell of any one of claims 1-20, wherein, The battery cell is a cylindrical battery cell, and a diameter of the cylindrical battery cell is greater than or equal to 35mm and less than or equal to 70mm.

22. A battery device comprising a plurality of battery cells according to any one of claims 1-21.

23. The battery device of claim 22, wherein, At least two of the battery cells are connected in parallel.

24. An electrical device comprising the battery device according to claim 22 or 23, the battery device being configured to provide electrical energy.

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