CN220984705U

CN220984705U - Battery monomer, battery and electric equipment

Info

Publication number: CN220984705U
Application number: CN202322349248.6U
Authority: CN
Inventors: 许宝云; 陈佳华; 欧阳少聪; 孙婧轩
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-08-30
Filing date: 2023-08-30
Publication date: 2024-05-17
Anticipated expiration: 2033-08-30

Abstract

The application provides a battery monomer, a battery and electric equipment, wherein the battery monomer comprises a shell, a pressure release mechanism, an electrode assembly and a gas generating part, the shell is provided with a containing cavity, the shell comprises a pressure release wall body, the pressure release mechanism is arranged on the pressure release wall body, the electrode assembly is contained in the containing cavity, the gas generating part is configured to generate gas after reaching a preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly. Because this default temperature is less than the thermal runaway critical temperature of electrode assembly, consequently, before electrode assembly takes place thermal runaway, the gas production spare can reach this default temperature and produce gas, and under the free internal pressure of battery is greater than the free pressure of relief mechanism's of pressure condition, the free relief mechanism of battery opens to release the inside heat of battery monomer, effectively reduced the thermal runaway condition further worsened risk of electrode assembly, thereby effectively improved the free security performance of battery.

Description

Battery monomer, battery and electric equipment

Technical Field

The application belongs to the technical field of batteries, and particularly relates to a battery monomer, a battery and electric equipment.

Background

Energy conservation and emission reduction are key to sustainable development of the automobile industry, and electric automobiles become an important component of sustainable development of the automobile industry due to the energy conservation and environmental protection advantages of the electric automobiles. For electric vehicles, battery technology is an important factor for development of the electric vehicles.

The battery includes a plurality of battery cells, and the battery cell includes electrode assembly, and in the battery cell charge-discharge process, the electrode assembly takes place thermal runaway easily, influences the security performance of battery.

Disclosure of utility model

The embodiment of the application aims to provide a battery monomer, a battery and electric equipment, so as to solve the technical problem of poor safety performance of the battery monomer in the related technology.

In order to achieve the above purpose, the technical scheme adopted by the embodiment of the application is as follows: provided is a battery cell including:

The shell is provided with a containing cavity and comprises a pressure release wall body;

the pressure release mechanism is arranged on the pressure release wall body;

An electrode assembly accommodated in the accommodating chamber;

the gas generating piece is accommodated in the accommodating cavity and is configured to generate gas after reaching a preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly.

The battery monomer provided by the embodiment of the application has at least the following beneficial effects: according to the battery monomer provided by the embodiment of the application, the gas generating part is arranged in the accommodating cavity of the shell, the gas generating part can generate gas after reaching the preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly, so that before the electrode assembly is in thermal runaway, the heat generated by the electrode assembly can be conducted to the gas generating part, the gas generating part can reach the preset temperature and generate gas, the internal pressure of the battery monomer is increased along with the continuous gas generation of the gas generating part, and under the condition that the internal pressure of the battery monomer is larger than the opening pressure of the pressure release mechanism, the pressure release mechanism of the battery monomer is opened to release the heat in the battery monomer. Therefore, the pressure release mechanism can be opened before the electrode assembly is in thermal runaway so as to release heat in the battery cell in advance, so that the risk of further deteriorating the thermal runaway condition of the electrode assembly is effectively reduced, the risk of thermal runaway of other electrode assemblies caused by the fact that the heat is spread from the electrode assembly in thermal runaway to other electrode assemblies is effectively reduced, and the safety performance of the battery cell is effectively improved.

In some embodiments of the application, the preset temperature is 90 ℃ to 130 ℃.

Through adopting above-mentioned technical scheme, the effective control gas piece produces gas before electrode assembly takes place thermal runaway for pressure release mechanism can be opened before electrode assembly takes place thermal runaway, in order to release the inside heat of battery monomer in advance, further reduced the further worsened risk of electrode assembly's thermal runaway condition, further reduced the heat and spread to other electrode assemblies from taking place thermal runaway's electrode assembly and lead to other electrode assemblies to take place thermal runaway's risk, thereby further improved the free security performance of battery.

In some embodiments of the application, the cavity is provided with a gas containing space for containing gas generated by the gas generating piece, and the gas yield V1 of the gas generating piece and the volume V2 of the gas containing space meet the relation that V1/V2 is less than or equal to 5 and less than or equal to 15.

Through adopting above-mentioned technical scheme, not only make the gas production V1 of gas production spare can satisfy the pressure demand that pressure release mechanism opened before electrode assembly takes place thermal runaway, can also effectively improve the condition that the quality of gas production spare is too big to the free quality energy density of battery has effectively been improved.

In some embodiments of the present application, the number of electrode assemblies is plural, and the gas generating member includes a gas generating material and a heat insulator, the heat insulator is disposed between two adjacent electrode assemblies, and the gas generating material is disposed on the heat insulator.

Through adopting above-mentioned technical scheme, make the gas production spare possess thermal-insulated function and gas production function simultaneously, not only effectively delayed the heat spreading speed between two adjacent electrode assemblies, effectively shortened the heat conduction route between electrode assemblies and the gas production thing moreover, more effectively control the gas production thing and produce gas before the electrode assemblies takes place thermal runaway to further improved the free security performance of battery.

In some embodiments of the application, a cavity is formed in the heat insulator, the cavity wall of the cavity is provided with a hole, the cavity is communicated with the containing cavity through the hole, and the gas generating substance is contained in the cavity.

By adopting the technical scheme, the heat generated by the electrode assembly can be effectively conducted onto the gas generating object, and the risk that the gas generating object is separated from the heat insulator is effectively reduced, so that the reliability of the gas generating object is effectively improved.

In some embodiments of the application, the insulator defines an aperture in communication with the cavity, and the gas generating material is disposed within the aperture.

In some embodiments of the application, the number of apertures is plural, and at least some of the apertures are disposed with their ports facing the pressure relief wall.

By adopting the technical scheme, the path from the gas generation object to the pressure release wall body is effectively shortened, the time from the gas generation object to the start of the gas generation to the opening of the pressure release mechanism is effectively shortened, and the safety performance of the battery monomer is further improved.

In some embodiments of the application, the gas-generating member further comprises a lyophobic, lyophobic covering the insulation and the gas-generating member.

Through adopting above-mentioned technical scheme for the electrolyte in gas production thing and the battery monomer can separate through lyophobic body, effectively reduced gas production thing and electrolyte contact and lead to gas production thing and electrolyte to take place the risk of chemical reaction, thereby effectively maintain gas production thing's chemical stability.

In some embodiments of the application, the lyophobic body is provided with a first weakening structure.

By adopting the technical scheme, the gas is convenient to break through the lyophobic liquid and is discharged to the outside of the lyophobic liquid.

In some embodiments of the application, the first weakness is disposed directly opposite the pressure relief wall.

In some embodiments of the application, the insulation is lyophobic insulation.

By adopting the technical scheme, the risk of chemical reaction between the gas generating substance and the electrolyte caused by contact of the gas generating substance and the electrolyte is effectively reduced, so that the chemical stability of the gas generating substance is effectively maintained.

In some embodiments of the present application, the gas-generating member includes a gas-generating substance and a lyophobic body that encapsulates the gas-generating substance.

In some embodiments of the present application, the number of electrode assemblies and the number of gas generating members are plural, and the plural gas generating members are disposed in one-to-one correspondence with the plural electrode assemblies.

Through adopting above-mentioned technical scheme, under the condition that one or more electrode assemblies is close to taking place thermal runaway, corresponding gas generating piece can be after reaching preset temperature and produce gas, effectively improved the reaction rate of gas generating piece for pressure release mechanism can take place before thermal runaway at one or more electrode assemblies and open, with the inside heat of release battery monomer in advance, further reduced the further worsened risk of thermal runaway condition of electrode assemblies, further reduced the heat and spread to other electrode assemblies and lead to other electrode assemblies to take place thermal runaway from the electrode assemblies that takes place thermal runaway risk, thereby further improved the single security performance of battery.

The embodiment of the application also provides a battery, which comprises the battery cell described in any one of the embodiments.

The battery provided by the embodiment of the application has at least the following beneficial effects: the battery provided by the embodiment of the application adopts the battery monomer of any embodiment, so that the safety performance of the battery is effectively improved.

In some embodiments of the present application, the battery further includes a battery management module electrically connected to the battery cell to detect an opening motion of the pressure release mechanism.

By adopting the technical scheme, under the condition that the battery management module detects the opening action of the pressure release mechanism, the battery management module can disconnect the circuit where the battery monomer is located so as to stop the operation of the battery monomer, thereby preventing the thermal runaway condition of the battery monomer from further deteriorating and further improving the safety performance of the battery.

The embodiment of the application also provides electric equipment, which comprises the battery.

The electric equipment provided by the embodiment of the application has at least the following beneficial effects: the electric equipment provided by the embodiment of the application adopts the battery described in any one embodiment, so that the safety performance of the electric equipment is effectively improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

fig. 2 is a schematic view of an exploded structure of a battery in the vehicle shown in fig. 1;

fig. 3 is a schematic structural view of a battery cell in the battery shown in fig. 2;

fig. 4 is an exploded view of the battery cell shown in fig. 3;

Fig. 5 is a schematic front view of the battery cell shown in fig. 3;

FIG. 6 is a schematic cross-sectional view of the battery cell shown in FIG. 5 along the line A-A;

Fig. 7 is a schematic structural view of a gas generating member in the battery cell shown in fig. 4;

FIG. 8 is a schematic view of the cross-sectional structure of the gas-generating member of FIG. 7 along line B-B;

FIG. 9 is an enlarged schematic view of the gas-generating member shown in FIG. 8 at C;

FIG. 10 is a schematic diagram showing a cross-sectional structure of the gas-generating member shown in FIG. 7 along line B-B;

FIG. 11 is an enlarged schematic view of the gas-generating member shown in FIG. 10 at D;

FIG. 12 is a schematic view of a cross-sectional structure of the gas-generating member shown in FIG. 7 taken along line B-B.

Wherein, each reference sign in the figure:

1000. A vehicle;

100. a battery;

10. a case; 11. a first portion; 12. a second portion;

20. A battery cell; 21. a housing; 211. a housing; 212. a cover body; 213. a cavity; 2131. the gas containing space; 22. a pressure release mechanism; 23. an electrode assembly; 24. a gas generating member; 241. a gas generating substance; 242. an insulator; 2421. a cavity; 2422. a void; 243. lyophobic; 2431. a first weak structure;

200. A controller;

300. a motor.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Currently, the more widely the battery is used in view of the development of market situation. The battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, as well as a plurality of fields such as military equipment, aerospace, and the like. With the continuous expansion of the battery application field, the market demand thereof is also continuously expanding.

In the related art, a battery includes a battery cell, which is a minimum storage unit for storing electric energy. The battery cell generally includes a plurality of electrode assemblies, and during the charge and discharge of the battery cell, the electrode assemblies are easily thermally out of control and release a large amount of heat, resulting in a rapid increase in the internal pressure of the battery cell, which easily results in explosion of the battery cell. In order to reduce the risk of explosion of the battery cell, a pressure release mechanism is usually arranged on the housing of the battery cell, and the pressure release mechanism is opened to release the internal pressure of the battery cell when the internal pressure of the battery cell reaches the opening pressure of the pressure release mechanism.

However, since the opening operation of the pressure release mechanism is delayed compared with the time node when the electrode assembly starts to generate thermal runaway, in the process from when the electrode assembly starts to generate thermal runaway to when the pressure release mechanism is opened, heat is easy to spread from the electrode assembly generating thermal runaway to other electrode assemblies, so that the other electrode assemblies generate thermal runaway along with the electrode assemblies, the risk of explosion of the battery cell is greatly improved, and the safety performance of the battery cell is greatly reduced.

In order to improve the safety performance of the battery monomer, the gas generating component is arranged in the accommodating cavity of the shell, and gas can be generated after the gas generating component reaches a preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly, so that before the electrode assembly is in thermal runaway, heat generated by the electrode assembly can be conducted to the gas generating component, the gas generating component can reach the preset temperature and generate gas, the internal pressure of the battery monomer is continuously increased along with the continuous gas generation of the gas generating component, and under the condition that the internal pressure of the battery monomer is larger than the opening pressure of the pressure releasing mechanism, the pressure releasing mechanism of the battery monomer is opened to release the heat in the battery monomer. Therefore, the pressure release mechanism can be opened before the electrode assembly is in thermal runaway so as to release heat in the battery cell in advance, so that the risk of further deteriorating the thermal runaway condition of the electrode assembly is effectively reduced, the risk of thermal runaway of other electrode assemblies caused by the fact that the heat is spread from the electrode assembly in thermal runaway to other electrode assemblies is effectively reduced, and the safety performance of the battery cell is effectively improved.

The battery cell, the battery and the electric equipment using the battery as the power supply disclosed by the embodiment of the application are applicable to vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like. Spacecraft include airplanes, rockets, space planes, spacecraft, and the like. The electric toy includes fixed or mobile electric toys such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy, and the like. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others.

For convenience of description, the following embodiment will take an electric device according to an embodiment of the present application as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to an embodiment of the application. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to an embodiment of the application. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide an accommodating space for the battery cell 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 being overlapped with each other, the first portion 11 and the second portion 12 together defining an accommodating space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one end opened, the first portion 11 may be a plate-shaped structure, and the first portion 11 is covered on the opening side of the second portion 12, so that the first portion 11 and the second portion 12 together define an accommodating space; the first portion 11 and the second portion 12 may be hollow structures with one side open, and the open side of the first portion 11 is disposed on the open side of the second portion 12. Of course, the case 10 formed by the first portion 11 and the second portion 12 may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In some embodiments, the tank 10 may be part of the chassis structure of the vehicle 1000. For example, a portion of the tank 10 may become at least a portion of the floor of the vehicle 1000, or a portion of the tank 10 may become at least a portion of the cross member and the side member of the vehicle 1000.

In the battery 100, the plurality of battery cells 20 may be connected in series, parallel or a series-parallel connection, wherein the series-parallel connection refers to that the plurality of battery cells 20 are connected in series or parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in series-parallel, and then the whole body formed by the plurality of battery cells 20 is accommodated in the box 10. Of course, the battery 100 may also be a battery module formed by connecting a plurality of battery cells 20 in series or parallel or series-parallel connection, and then connecting a plurality of battery modules in series or parallel or series-parallel connection to form a whole and be accommodated in the case 10. The battery 100 may also include other functional components, for example, the battery 100 may also include a buss bar for making electrical connection between the plurality of battery cells 20.

Each of the battery cells 20 may be a secondary battery or a primary battery, wherein the secondary battery refers to a battery cell 20 that can activate an active material by charging after the battery cell 20 discharges and continue to be used, and the primary battery refers to a battery cell 20 that cannot activate an active material by charging after the battery cell 20 is depleted of electric energy; the battery cell 20 may be, but not limited to, a lithium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, or the like. The battery cell 20 may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or other shaped battery cell 20, and the prismatic battery cell includes a square-case battery cell, a blade-shaped battery cell, a polygonal-prismatic battery cell, such as a hexagonal-prismatic battery cell, etc., and the present application is not particularly limited.

Of course, in some embodiments, the battery 100 may not include the case 10, but rather, a plurality of battery cells 20 may be electrically connected and assembled into the vehicle 1000 after being integrally formed with a necessary fixing structure.

In order to explain the technical scheme provided by the application, the following is a detailed description with reference to the specific drawings and embodiments.

Referring to fig. 3 to 6, an embodiment of the application provides a battery cell 20, which includes a housing 21, a pressure release mechanism 22, an electrode assembly 23 and a gas generating member 24. The housing 21 has a cavity 213 and the housing 21 includes a pressure relief wall. The pressure release mechanism 22 is disposed on the pressure release wall. The electrode assembly 23 is received in the receiving chamber 213. The gas generating member 24 is accommodated in the accommodating chamber 213, and the gas generating member 24 is configured to generate gas after reaching a preset temperature, which is less than a thermal runaway critical temperature of the electrode assembly 23.

The housing 21 may include a case 211 and a cover 212. Wherein the case 211 is a member for providing an internal environment of the battery cell 20 (i.e., the above-described receiving cavity 213), which may be used to accommodate the electrode assembly 23 and other functional components. The case 211 may be a separate member, and an opening may be provided in the case 211, through which the electrode assembly 23 and the like may be accommodated in the internal environment. The shape of the case 211 may be determined according to the specific shape of the electrode assembly 23, the shape of the case 211 may be, but not limited to, a rectangular parallelepiped shape, a cylindrical shape, a hexagonal prism shape, etc., and the size of the case 211 may be determined according to the size of the electrode assembly 23. The material of the housing 211 may be, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, etc. The cover 212 is a member that covers the opening of the case 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover 212 may be adapted to the shape of the housing 211 to fit the housing 211. In some embodiments, the cover 212 may be made of a material with a certain hardness and strength, so that the cover 212 is not easy to deform when being extruded and collided, so that the battery cell 20 can have a higher structural strength, the safety performance can be improved, and the material of the cover 212 may be, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, and the like. In some embodiments, the cover 212 forms the pressure relief wall described above. Of course, in other embodiments, any wall of the housing 211 may form the pressure release wall. In other words, the pressure release mechanism 22 may be provided on the cover 212 or on any wall of the housing 211.

The pressure release mechanism 22 is a means for releasing the internal pressure of the battery cell 20 when the internal pressure reaches a threshold value (i.e., a cracking pressure described below). The threshold may be dependent on the design requirements of the battery cell 20. The above threshold may depend on the material of one or more of the positive electrode sheet, the negative electrode sheet, the electrolyte, and the separator within the battery cell 20. The pressure relief mechanism 22 may be, but is not limited to, an explosion proof valve, a gas valve, a pressure relief valve, a safety valve, or the like. The pressure relief mechanism 22 may include a through-hole portion and a second frangible structure. The through hole part penetrates through the pressure release wall body along the thickness direction of the pressure release wall body. The second weak structure is used for plugging the through hole part. In the case that the internal pressure of the battery cell 20 is smaller than the opening pressure of the pressure release mechanism 22, the second weak structure does not act to block the through hole portion, so that the internal environment of the battery cell 20 is isolated from the external environment; in the case where the internal pressure of the battery cell 20 reaches the opening pressure of the pressure release mechanism 22, the second weak structure is broken to communicate the internal environment of the battery cell 20 with the external environment, so that the internal pressure of the battery cell 20 is released to the external environment of the battery cell 20.

The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. The number of the electrode assemblies 23 may be determined according to practical application requirements, for example, the number of the electrode assemblies 23 is two, three, four, five, etc. The shape of the electrode assembly 23 may be, but is not limited to, cylindrical, flat, or polygonal column, etc. The electrode assembly 23 is mainly made of a positive electrode sheet, a negative electrode sheet, and a separator using a winding process or a lamination process. In some embodiments, a plurality of positive electrode sheets and negative electrode sheets may be provided, respectively, and a plurality of positive electrode sheets and a plurality of negative electrode sheets may be alternately stacked. In other embodiments, a plurality of positive plates may be provided, and the negative plates are folded to form a plurality of folded sections arranged in a stacked manner, and one positive plate is clamped between adjacent folded sections. In still other embodiments, both the positive and negative electrode sheets are folded to form a plurality of folded segments in a stacked arrangement. In some embodiments, a plurality of separators may be provided, and a plurality of separators may be provided separately between any adjacent positive or negative electrode sheets. In other embodiments, the separator may be disposed continuously, by being folded or rolled, between any adjacent positive or negative electrode sheets. The positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector. As an example, the positive electrode current collector has two surfaces opposing in its own thickness direction, and the positive electrode active material is provided on either or both of the two surfaces opposing the positive electrode current collector. The negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector. As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode active material is provided on either or both of the two surfaces opposing the anode current collector. In some embodiments, the separator is a separator, and the application is not particularly limited in the type of separator, and any known porous separator having good chemical stability and mechanical stability may be used. The battery cell 20 may further include an electrolyte that plays a role in conducting ions between the positive electrode sheet and the negative electrode sheet, and the kind of the electrolyte is not particularly limited in the present application and may be selected according to the need. During charge and discharge of the battery cell 20, active ions (e.g., lithium ions, sodium ions, etc.) are inserted and extracted back and forth between the positive and negative electrode sheets through the electrolyte. The separator is arranged between the positive plate and the negative plate, can play a role in preventing the positive plate and the negative plate from being short-circuited, and can enable active ions to pass through.

The gas generating member 24 is a member for generating gas to increase the internal pressure of the battery cell 20 before thermal runaway of the electrode assembly 23 occurs. The gas generating member 24 at least comprises a gas generating member 241, wherein the gas generating member 241 is capable of generating gas after reaching a predetermined temperature, the type of the gas generating member 241 can be determined according to the type of the battery cell 20, the predetermined temperature of different gas generating members 241 is different, and the gas generating member 241 can be, but is not limited to, sodium bicarbonate, ammonium bicarbonate, oxalic acid, etc. The gas generating member 24 may be disposed at any position in the cavity 213 of the casing 21, and the gas generating substance 241 of the gas generating member 24 may contact the electrode assembly 23 or may be disposed at a distance from the electrode assembly 23. In some embodiments, in the case where the number of electrode assemblies 23 is plural, the gas generating member 24 is disposed between adjacent two electrode assemblies 23, and the gas generating substance 241 of the gas generating member 24 contacts the electrode assemblies 23. In other embodiments, the gas generating member 24 is disposed between the cover 212 and the electrode assembly 23, and the gas generating substance 241 of the gas generating member 24 contacts the electrode assembly 23. In still other embodiments, the gas generating member 24 is disposed between any one of the walls of the housing 211 and the electrode assembly 23, and the gas generating substance 241 of the gas generating member 24 contacts the electrode assembly 23.

In the related art, the battery cell 20 is generally electrically connected to an external control module (e.g., a battery management module of the battery 100), the external control module can detect the opening of the pressure release mechanism 22, and when the external control module detects the opening of the pressure release mechanism 22, the external control module can disconnect the circuit of the battery cell 20, so that the battery cell 20 stops working, thereby preventing the thermal runaway condition of the battery cell 20 from further worsening.

According to the battery cell 20 provided by the embodiment of the application, the gas generating member 24 is arranged in the accommodating cavity 213 of the housing 21, the gas generating member 24 can generate gas after reaching the preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly 23, so that before the electrode assembly 23 is in thermal runaway, the heat generated by the electrode assembly 23 can be conducted to the gas generating member 24, the gas generating member 24 can reach the preset temperature and generate gas, and along with the continuous generation of the gas by the gas generating member 24, the internal pressure of the battery cell 20 is continuously increased, and under the condition that the internal pressure of the battery cell 20 is larger than the opening pressure of the pressure release mechanism 22, the pressure release mechanism 22 of the battery cell 20 is opened to release the heat in the battery cell 20. In this way, the pressure release mechanism 22 can be opened before the thermal runaway of the electrode assembly 23 occurs to release the heat inside the battery cell 20 in advance, so that not only is the risk of further worsening of the thermal runaway condition of the electrode assembly 23 effectively reduced, but also the risk of thermal runaway of other electrode assemblies 23 caused by the heat spreading from the electrode assembly 23 which is in thermal runaway to other electrode assemblies 23 is effectively reduced, and the safety performance of the battery cell 20 is effectively improved.

The preset temperature may be specifically determined according to the kind of the battery cell 20, for example, the preset temperature is 90 ℃, 100 ℃,110 ℃,120 ℃,130 ℃, etc.

By adopting the above technical scheme, the gas generating member 24 is effectively controlled to generate gas before the electrode assembly 23 is subject to thermal runaway, so that the pressure release mechanism 22 can be opened before the electrode assembly 23 is subject to thermal runaway to release the heat inside the battery cell 20 in advance, the risk of further deteriorating the thermal runaway condition of the electrode assembly 23 is further reduced, the risk of thermal runaway caused by the heat spreading from the electrode assembly 23 subject to thermal runaway to other electrode assemblies 23 is further reduced, and the safety performance of the battery cell 20 is further improved.

In some implementations of the application, the battery cell 20 is a sodium ion battery cell and the gas product 241 of the gas generating member 24 is sodium bicarbonate, in other words, the gas generating member 24 is sodium bicarbonate.

In the related art, the thermal runaway critical temperature of the electrode assembly 23 of the sodium ion battery cell is generally about 130 c to 150 c, and sodium bicarbonate can generate carbon dioxide after reaching a preset temperature of about 90 c to 130 c. Through adopting above-mentioned technical scheme, the required preset temperature that reaches of sodium bicarbonate production gas can with the thermal runaway critical temperature looks adaptation of sodium ion battery monomer's electrode assembly 23, the gas is produced before electrode assembly 23 takes place thermal runaway to effective control gas production spare 24 for release mechanism 22 can take place thermal runaway before opening at electrode assembly 23, in order to release the inside heat of battery monomer 20 in advance, sodium bicarbonate spare can produce carbon dioxide gas after reaching preset temperature moreover, carbon dioxide gas can not burn, the risk of battery monomer 20 taking place the fire explosion has effectively been reduced, thereby further improved the security performance of battery monomer 20.

In some embodiments of the present application, referring to FIG. 6, the chamber 213 has a gas-containing space 2131 for containing the gas generated by the gas generating member 24, and the gas yield V1 of the gas generating member 24 and the volume V2 of the gas-containing space 2131 satisfy the relationship of 5.ltoreq.V1/V2.ltoreq.15.

The gas containing space 2131 refers to other spaces of the containing chamber 213 except for the space for accommodating the electrode assembly 23, electrolyte, etc., and it is understood that other components are substantially absent in the gas containing space 2131 in the case where the battery cell 20 is used normally and the gas generating member 24 does not generate gas.

The gas yield V1 of the gas generating member 24 refers to the volume of gas generated by the gas generating member 24 after reaching a predetermined temperature. The gas yield V1 of the gas generating member 24 depends on the mass of the gas generating member 241 of the gas generating member 24, and the larger the mass of the gas generating member 241 is, the larger the gas yield V1 of the gas generating member 24 is, whereas the smaller the mass of the gas generating member 241 is, the smaller the gas yield V1 of the gas generating member 24 is. The relation between the gas yield V1 of the gas generating member 24 and the volume V2 of the gas containing space 2131 is that V1/V2 is equal to or less than 5 and 15, i.e. the ratio of the gas yield V1 of the gas generating member 24 to the volume V2 of the gas containing space 2131 is greater than or equal to 5 and less than or equal to 15, for example, the ratio of the gas yield V1 of the gas generating member 24 to the volume V2 of the gas containing space 2131 may be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

By adopting the above technical scheme, not only the gas yield V1 of the gas generating member 24 can meet the pressure requirement that the pressure release mechanism 22 is opened before the thermal runaway of the electrode assembly 23, but also the condition that the quality of the gas generating member 24 is too large can be effectively improved, thereby effectively improving the quality energy density of the battery cell 20.

In some embodiments of the present application, referring to fig. 3 to 11, the number of the electrode assemblies 23 is plural, the gas generating member 24 further includes a heat insulator 242, the heat insulator 242 is disposed between two adjacent electrode assemblies 23, and the gas generating member 241 is disposed on the heat insulator 242.

The heat insulator 242 is a member for blocking heat conduction between the adjacent two electrode assemblies 23. In some embodiments, the number of electrode assemblies 23 is two, and the insulator 242 is disposed between the two electrode assemblies 23. In other embodiments, the number of electrode assemblies 23 is more than two, and the heat insulator 242 may be disposed between every two adjacent electrode assemblies 23, or the plurality of electrode assemblies 23 may be divided into a plurality of groups, and the heat insulator 242 may be disposed between every two adjacent groups of electrode assemblies 23. Insulation 242 may be, but is not limited to, insulation pads, insulation panels, insulation films, and the like. The material of the heat insulator 242 may be, but is not limited to, porous silicon, aerogel, polyphenyl, rock wool, glass wool, polyurethane foam, etc. In some embodiments, insulation 242 covers the entire surface of one electrode assembly 23 relative to the other electrode assembly 23. Of course, in other embodiments, the insulator 242 may cover only a portion of the surface of one electrode assembly 23 relative to the other electrode assembly 23. The heat insulator 242 may be attached between adjacent two electrode assemblies 23, and the heat insulator 242 may be further disposed at a distance from the electrode assemblies 23.

By adopting the technical scheme, the gas generating piece 24 has the heat insulation function and the gas generating function, so that the heat spreading speed between two adjacent electrode assemblies 23 is effectively delayed, the heat conduction path between the electrode assemblies 23 and the gas generating object 241 is effectively shortened, the gas generated by the gas generating object 241 before the electrode assemblies 23 are out of control, and the safety performance of the battery cell 20 is further improved.

In some embodiments of the present application, referring to fig. 8 and 9, a cavity 2421 is formed in the heat insulator 242, the cavity 2421 has a cavity wall with a hole 2422, the cavity 2421 is communicated with the cavity 213 through the hole 2422, and the gas generating substance 241 is contained in the cavity 2421.

It can be understood that the heat insulator 242 is a hollow structure, the hollow portion of the heat insulator 242 forms the cavity 2421, the hole 2422 is formed on the wall of the cavity 2421, the hole 2422 penetrates through the wall of the cavity 2421 to communicate the cavity 2421 with the cavity 213, the heat generated by the electrode assembly 23 can enter the cavity 2421 through the hole 2422 and be conducted onto the gas generating object 241, so that the gas generating object 241 can reach the preset temperature, and accordingly, the gas generated by the gas generating object 241 after reaching the preset temperature can be discharged to the cavity 213 through the hole 2422, so that the internal pressure of the battery cell 20 is increased, and the pressure releasing mechanism 22 is opened to release the internal pressure of the battery cell 20 when the internal pressure of the battery cell 20 reaches the opening pressure of the pressure releasing mechanism 22.

By adopting the technical scheme, not only can the heat generated by the electrode assembly 23 be effectively conducted to the gas generating object 241, but also the risk that the gas generating object 241 is separated from the heat insulator 242 is effectively reduced, so that the reliability of the gas generating piece 24 is effectively improved.

In some embodiments of the present application, referring to fig. 10 and 11, the heat insulator 242 has a hole 2422 in communication with the cavity 213, and the gas generating material 241 is disposed in the hole 2422.

In some embodiments, referring to fig. 11, the aperture 2422 is a through hole structure, i.e., the aperture 2422 extends through opposite sides of the insulator 242 to communicate with the cavity 213, e.g., the aperture 2422 extends through the side of the insulator 242 facing one electrode assembly 23 and the side of the insulator 242 facing the other electrode assembly 23.

In other embodiments, the hole 2422 is a blind hole structure, i.e. one end of the hole 2422 is closed, and the other end of the hole 2422 penetrates the surface of the insulator 242 to communicate with the cavity 213. For example, the number of the holes 2422 may be plural, a portion of the holes 2422 being opened at a side of the heat insulator 242 facing one electrode assembly 23, and another portion of the holes 2422 being opened at a side of the heat insulator 242 facing the other electrode assembly 23.

In some embodiments of the application, the number of apertures 2422 is multiple, at least some of the ports of the apertures 2422 being positioned directly opposite the pressure relief wall.

It should be noted that the opposite arrangement of the port of the aperture 2422 and the pressure release wall means that the port of the aperture 2422 faces the pressure release wall, and no spacer exists between the aperture 2422 and the pressure release wall.

In some embodiments, all the holes 2422 are formed on a side of the heat insulation body 242 facing the pressure release wall body, and the ports of all the holes 2422 penetrate through the surface of the heat insulation body 242 facing the pressure release wall body, and may be that the ports of one part of the holes 2422 are opposite to the pressure release mechanism 22, and the ports of the other part of the holes 2422 are opposite to the pressure release wall body.

In other embodiments, a portion of the apertures 2422 are formed in the side of the thermal insulation 242 facing the pressure relief mechanism 22, the ports of the portion of the apertures 2422 extend through the side surface of the thermal insulation 242 facing the pressure relief wall, another portion of the apertures 2422 are formed in the side of the thermal insulation 242 facing the electrode assembly 23, and the ports of the portion of the apertures 2422 extend through the side surface of the thermal insulation 242 facing the electrode assembly 23.

In still other embodiments, a portion of the apertures 2422 are open on a side of the thermal insulation 242 facing the pressure relief mechanism 22, the ports of the portion of the apertures 2422 extend through a side surface of the thermal insulation 242 facing the pressure relief wall, another portion of the apertures 2422 are open on a side of the thermal insulation 242 facing the interior wall of the housing 211, and the ports of the portion of the apertures 2422 extend through a side surface of the thermal insulation 242 facing the interior wall of the housing 211.

In still other embodiments, a portion of the apertures 2422 are open on the side of the insulator 242 facing the pressure relief mechanism 22, the ports of the portion of the apertures 2422 extend through the side surface of the insulator 242 facing the pressure relief wall, another portion of the apertures 2422 are open on the side of the insulator 242 facing the electrode assembly 23, the ports of the portion of the apertures 2422 extend through the side surface of the insulator 242 facing the electrode assembly 23, yet another portion of the apertures 2422 are open on the side of the insulator 242 facing the interior wall of the housing 211, and the ports of the portion of the apertures 2422 extend through the side surface of the insulator 242 facing the interior wall of the housing 211.

By adopting the technical scheme, the path from the gas generated by the gas generating substance 241 to the pressure release wall body is effectively shortened, and the time from the start of gas generation by the gas generating substance 241 to the start of the pressure release mechanism 22 is effectively shortened, so that the safety performance of the battery cell 20 is further improved.

In some embodiments of the present application, referring to fig. 8-11, the gas generating member 24 further includes a lyophobic body 243, wherein the lyophobic body 243 encapsulates the heat insulator 242 and the gas generating member 241.

The lyophobic body 243 is a member for separating the heat insulator 242 and the gas generating body 241 from the electrolyte of the battery cell 20. In some embodiments, the lyophobic 243 covers the entire surface of the insulation 242. Of course, in other embodiments, the lyophobic body 243 may cover only a part of the surface of the heat insulator 242 immersed in the electrolyte solution, and the gas generating material 241 may be disposed within a range where the heat insulator 242 is covered with the lyophobic body 243. In some embodiments, the lyophobic 243 is a lyophobic film that is attached to the surface of the insulation 242. In other implementations, the lyophobic 243 is a lyophobic coating that is applied to the surface of the insulation 242. The material of the lyophobic 243 may be, but is not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, etc.

Through adopting above-mentioned technical scheme, under the condition that electrolyte is electrolyte for the electrolyte in gas production thing 241 and the battery monomer 20 can separate through the lyophobic 243, effectively reduced gas production thing 241 and electrolyte contact and lead to gas production thing 241 and electrolyte to take place the risk of chemical reaction to effectively maintain the chemical stability of gas production thing 241.

In some embodiments of the present application, referring to fig. 9 and 11, the lyophobic 243 is provided with a first weakening structure 2431.

It can be appreciated that the strength of the first weak structure 2431 is smaller than that of other parts of the lyophobic body 243, so that the gas generated after the gas generating material 241 reaches the preset temperature can first break the first weak structure 2431 and be discharged to the cavity 213.

In some embodiments, the thickness of the first weakening structure 2431 is smaller than the thickness of other portions of the lyophobic body 243 such that the strength of the first weakening structure 2431 is smaller than the strength of other portions of the lyophobic body 243, e.g., the first weakening structure 2431 is a scored structure.

In other embodiments, the material of the first weak structure 2431 is different from the material of the other parts of the lyophobic body 243, and the strength of the material of the first weak structure 2431 is smaller than the strength of the material of the other parts of the lyophobic body 243.

By adopting the above technical scheme, the gas is facilitated to break through the lyophobic body 243 and discharge to the outside of the lyophobic body 243.

In some embodiments of the application, the first weakness 2431 is disposed directly opposite the pressure relief wall.

It should be noted that the arrangement of the first weak structure 2431 opposite to the pressure release wall body means that the first weak structure 2431 faces the pressure release wall body and no spacer exists between the first weak structure 2431 and the pressure release wall body.

In some embodiments of the present application, when the heat insulator 242 is provided with the hole 2422, the hole 2422 is opposite to the first weak structure 2431, and the first weak structure 2431 is opposite to the pressure release wall, so that the path from the gas generated by the gas generating substance 241 to the pressure release wall is effectively shortened, the time from the gas generating substance 241 to the opening of the pressure release mechanism 22 is effectively shortened, and the safety performance of the battery cell 20 is further improved.

In some embodiments of the application, the insulation 242 is lyophobic insulation 242.

In other words, in the present embodiment, the heat insulator 242 is made of a material having both heat insulating properties and lyophobic properties, for example, a surface branched fluorinated modified material of polyacrylonitrile, a surface branched fluorinated modified material of polycaprolactone, or a surface branched fluorinated modified material of polysulfone.

By adopting the technical scheme, under the condition that the electrolyte is electrolyte, the risk of chemical reaction between the gas generating substance 241 and the electrolyte caused by contact of the gas generating substance 241 and the electrolyte is effectively reduced, so that the chemical stability of the gas generating substance 241 is effectively maintained.

In some embodiments of the present application, referring to fig. 12, the gas generating member 24 includes a gas generating substance 241 and a lyophobic body 243, and the lyophobic body 243 encapsulates the gas generating substance 241.

It will be appreciated that in this embodiment, the gas generating member 24 does not include the heat insulator 242, but the lyophobic body 243 directly covers the gas generating member 24 may be disposed at any position in the cavity 213. In some embodiments, in the case where the number of electrode assemblies 23 is plural, the gas generating member 24 is disposed between adjacent two electrode assemblies 23. In other embodiments, the gas generating member 24 is disposed between the cover 212 and the electrode assembly 23. In still other embodiments, the gas generating member 24 is disposed between any of the walls of the housing 211 and the electrode assembly 23.

In some embodiments of the present application, referring to fig. 12, the lyophobic body 243 is provided with a first weak structure 2431.

In some embodiments of the present application, the number of electrode assemblies 23 and the number of gas generating members 24 are plural, and the plural gas generating members 24 are disposed in one-to-one correspondence with the plural electrode assemblies 23.

The gas generating members 24 may be disposed against the respective electrode assemblies 23, or may be disposed adjacent to and spaced apart from the respective electrode assemblies 23, so that heat generated from each electrode assembly 23 can be rapidly conducted to the respective gas generating member 24.

By adopting the above technical scheme, under the condition that one or more electrode assemblies 23 are close to the occurrence of thermal runaway, the corresponding gas generating piece 24 can generate gas after reaching the preset temperature, so that the reaction speed of the gas generating piece 24 is effectively improved, the pressure release mechanism 22 can be opened before the occurrence of the thermal runaway of one or more electrode assemblies 23 so as to release the heat inside the battery cell 20 in advance, the risk of further deterioration of the thermal runaway condition of the electrode assemblies 23 is further reduced, the risk of thermal runaway of other electrode assemblies 23 caused by the fact that the heat is spread from the electrode assemblies 23 with the occurrence of the thermal runaway to the other electrode assemblies 23 is further reduced, and the safety performance of the battery cell 20 is further improved.

In some embodiments of the present application, referring to fig. 3 to 9, the battery cell 20 is electrically connected to an external control module, and the external control module is used for detecting the opening action of the pressure release mechanism 22. The battery cell 20 includes a housing 21, a pressure relief mechanism 22, an electrode assembly 23, and a gas generating member 24. The housing 21 has a cavity 213 and the housing 21 includes a pressure relief wall. The pressure release mechanism 22 is disposed on the pressure release wall. The electrode assemblies 23 are plural in number and accommodated in the accommodating chamber 213. The gas generating member 24 is accommodated in the accommodating chamber 213, and the gas generating member 24 is configured to generate gas after reaching a preset temperature, which is less than a thermal runaway critical temperature of the electrode assembly 23. The gas generating member 24 includes a gas generating member 241, a heat insulating member 242 and a lyophobic member 243, the heat insulating member 242 is disposed between two adjacent electrode assemblies 23, a cavity 2421 is formed in the heat insulating member 242, and the cavity wall of the cavity 2421 is provided with a hole 2422. Gas generating substance 241 is contained in cavity 2421. The lyophobic body 243 coats the heat insulator 242 and the gas generating object 241, the lyophobic body 243 is provided with a first weak structure 2431, and the first weak structure 2431 is opposite to the pressure release wall body. The battery cell 20 is a sodium ion battery cell, the thermal runaway critical temperature of the electrode assembly 23 of the sodium ion battery 100 is about 130 ℃ to 150 ℃, the gas generating substance 241 is ammonium bicarbonate, and the preset temperature required for generating gas by the ammonium bicarbonate is about 90 ℃ to 130 ℃. The containing cavity 213 is provided with a containing space 2131 for containing the gas generated by the gas generating component 24, and the gas yield V1 of the gas generating component 24 and the volume V2 of the containing space 2131 satisfy the relation that V1/V2 is more than or equal to 5 and less than or equal to 15. Before thermal runaway occurs in the electrode assembly 23 of the sodium ion battery 100, heat generated by the electrode assembly 23 passes through the lyophobic body 243 and enters the cavity 2421 through the hole 2422 of the heat insulator 242, and finally is conducted to the gas generating object 241, so that the gas generating object 241 reaches a preset temperature and generates gas, when the gas accumulates in the lyophobic body 243 to reach a certain amount, the gas breaks through the first weak structure 2431 and flows into the gas containing space 2131 of the containing cavity 213, as the gas increases continuously, the internal pressure of the battery cell 20 increases continuously, and when the internal pressure of the battery cell 20 reaches the opening pressure of the pressure relief mechanism 22, the pressure relief mechanism 22 opens to release the internal pressure of the battery cell 20, at this time, an external control module (for example, a battery management module of the battery 100) can detect the opening action of the pressure relief mechanism 22, and then disconnect the circuit where the battery cell 20 is located, so that before thermal runaway occurs in the electrode assembly 23, the thermal runaway operation of the battery 100 can be performed, thereby preventing the thermal runaway condition of the electrode assembly 23 from further, effectively reducing the thermal runaway from the electrode assembly 23 to the other thermal runaway components 23, and further improving the safety risks of the other battery cells, and further improving the performance of the battery cell 23.

In a second aspect, referring to fig. 2, an embodiment of the present application further provides a battery 100, including the battery cell 20 according to any one of the above embodiments.

Since the battery 100 provided in the embodiment of the present application adopts the battery cell 20 described in any one of the embodiments, the safety performance of the battery 100 is effectively improved.

In some embodiments of the present application, the battery 100 further includes a battery management module (not shown) electrically connected to the battery cell 20 to detect the opening of the pressure release mechanism 22.

By adopting the above technical solution, when the battery management module detects the opening action of the pressure release mechanism 22, the battery management module will disconnect the circuit where the battery cell 20 is located, so that the battery cell 20 stops working, and because the battery 100 provided by the embodiment of the application adopts the battery cell 20 described in any one of the embodiments, under the action of the gas generating member 24, the pressure release mechanism 22 can be opened before the thermal runaway of the electrode assembly 23 occurs, and after the pressure release mechanism 22 is opened, the battery management module will disconnect the circuit where the battery cell 20 is located, so that the battery cell 20 stops working, thereby preventing the thermal runaway condition of the battery cell 20 from further worsening.

In some embodiments, the battery unit 20 further includes a sensor (not shown) for detecting the opening of the pressure release mechanism 22, where the sensor is electrically connected to the battery management module to transmit a detection signal to the battery management module, and the battery management module determines whether the pressure release mechanism 22 is opened according to the detection signal, where the sensor may be, but is not limited to, an electromagnetic sensor, a temperature sensor, an optical sensor, an ultrasonic sensor, etc.

In a third aspect, referring to fig. 1, an embodiment of the present application further provides an electric device, including the battery 100.

Because the electric equipment provided by the embodiment of the application adopts the battery 100 in any one of the embodiments, the safety performance of the electric equipment is effectively improved.

The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.

Claims

1. A battery cell, the battery cell comprising:

the pressure release mechanism is arranged on the pressure release wall body;

An electrode assembly accommodated in the accommodating chamber;

And the gas generating piece is accommodated in the accommodating cavity and is configured to generate gas after reaching a preset temperature, and the preset temperature is smaller than the thermal runaway critical temperature of the electrode assembly.

2. The battery cell of claim 1, wherein the predetermined temperature is 90 ℃ to 130 ℃.

3. The battery cell according to claim 1, wherein the containing cavity is provided with a containing space for containing gas generated by the gas generating piece, and the gas yield V1 of the gas generating piece and the volume V2 of the containing space meet the relation that V1/V2 is more than or equal to 5 and less than or equal to 15.

4. The battery cell according to any one of claims 1-3, wherein the number of the electrode assemblies is plural, the gas generating member includes a gas generating material and a heat insulator, the heat insulator is disposed between two adjacent electrode assemblies, and the gas generating material is disposed on the heat insulator.

5. The battery cell as recited in claim 4, wherein a cavity is formed in the heat insulator, a hole is formed in a wall of the cavity, the cavity is communicated with the containing cavity through the hole, and the gas generating material is contained in the cavity.

6. The battery cell of claim 5, wherein the number of apertures is a plurality, and at least a portion of the ports of the apertures are disposed directly opposite the pressure relief wall.

7. The battery cell of claim 4, wherein the thermal insulator defines a void in communication with the cavity, and wherein the gas generating material is disposed within the void.

8. The battery cell of claim 7, wherein the number of apertures is a plurality, at least a portion of the ports of the apertures being disposed directly opposite the pressure relief wall.

9. The battery cell of claim 4, wherein the gas-generating member further comprises a lyophobic body surrounding the thermal insulator and the gas-generating member.

10. The battery cell of claim 9, wherein the lyophobic body is provided with a first weak structure.

11. The battery cell of claim 10, wherein the first weakness is disposed directly opposite the pressure relief wall.

12. The battery cell of claim 4, wherein the insulator is a lyophobic insulator.

13. The battery cell of any one of claims 1-3, wherein the gas generating member comprises a gas generating substance and a lyophobic body that encapsulates the gas generating substance.

14. The battery cell of claim 13, wherein the lyophobic body is provided with a first weak structure.

15. The battery cell of claim 14, wherein the first weakness is disposed directly opposite the pressure relief wall.

16. The battery cell according to claim 13, wherein the number of the electrode assemblies and the number of the gas generating members are plural, and the plural gas generating members are disposed in one-to-one correspondence with the plural electrode assemblies.

17. A battery comprising the battery cell of any one of claims 1-16.

18. The battery of claim 17, further comprising a battery management module electrically coupled to the battery cells to detect an opening of the pressure relief mechanism.

19. A powered device comprising the battery of claim 18.