Battery monomer, battery and electric equipment

Abstract

The utility model discloses a battery monomer, a battery and electric equipment, the battery monomer comprises a shell and an exhaust assembly, and the shell is provided with a wall part; the exhaust assembly is arranged on the wall part and comprises a one-way valve and / or a gas-permeable membrane assembly, the gas-permeable membrane assembly comprises a gas-permeable membrane, and the exhaust assembly is used for exhausting gas in the shell; the wall part is provided with a first strength weak area, and the first strength weak area is arranged in the circumferential direction of the exhaust assembly. Through the arrangement, gas in the shell of the battery monomer can be exhausted out of the shell in time, and meanwhile, when the pressure or temperature in the battery monomer reaches a threshold value, the pressure in the battery monomer is released.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] Batteries are increasingly used as a new energy source, and they have high requirements for reliability and service life. During the charging and discharging process of battery cells, the internal pressure of the battery cells will increase due to the generation of gas inside the battery cells. If the generated gas is not discharged in time, when the internal pressure or temperature of the battery cells reaches the threshold, it is easy to cause dangers such as explosion. The above statements are only used to provide background technical information related to this application, and do not necessarily constitute prior art. Summary of the invention

[0003] The main technical problem solved by the present application is to provide a battery cell, a battery and an electrical device, which can discharge the gas inside the battery cell shell to the outside of the shell in time, and release the pressure inside the battery cell when the pressure or temperature inside the battery cell reaches a threshold.

[0004] In order to solve the above technical problems, a technical solution adopted by the present application is: provide a battery cell, the battery cell includes a shell and an exhaust assembly, the shell has a wall portion; the exhaust assembly is arranged on the wall portion, the exhaust assembly includes a one-way valve and / or a breathable membrane assembly, the breathable membrane assembly includes a breathable membrane, and the exhaust assembly is used to exhaust the gas inside the shell; a first strength weak area is arranged on the wall portion, and the first strength weak area is arranged along the circumference of the exhaust assembly. Through this arrangement, the gas inside the battery cell shell can be discharged to the outside of the shell in time, and at the same time, when the pressure or temperature inside the battery cell reaches a threshold, the pressure inside the battery cell is released.

[0005] According to one embodiment of the present application, the first strength weak area includes a first thickness weak area. This arrangement is helpful to simplify the preparation process.

[0006] According to one embodiment of the present application, the first weak strength area includes a first groove that is recessed relative to the surface of the wall portion, and the first groove is arranged around the exhaust component. This arrangement is conducive to simplifying the preparation process.

[0007] According to one embodiment of the present application, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the shell, and the inner surface is disposed toward the inside of the shell; the first groove is recessed relative to the outer surface; and / or the first groove is recessed relative to the inner surface. This arrangement is conducive to further reducing the strength of the first weak strength zone.

[0008] According to one embodiment of the present application, the first weak strength area includes a plurality of second grooves that are recessed relative to the surface of the wall portion, and the plurality of second grooves are arranged at intervals in the circumferential direction of the exhaust component. This arrangement is conducive to simplifying the manufacturing process.

[0009] According to one embodiment of the present application, the first weak strength area further includes a notch arranged at the bottom of the first groove and / or the second groove. This arrangement is conducive to further reducing the strength of the first weak strength area.

[0010] According to one embodiment of the present application, the wall portion includes a wall portion body and a sinking portion, the wall portion body has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the shell, and the inner surface is disposed toward the inside of the shell; the sinking portion is connected to the wall portion body, the sinking portion protrudes from the inner surface, and the first strength weak zone is disposed on the sinking portion. This arrangement is conducive to further reducing the strength of the first strength weak zone.

[0011] According to one embodiment of the present application, the wall is provided with a first exhaust hole, the first exhaust hole communicates with the inside of the shell and the outside of the shell, and the exhaust assembly includes a one-way valve, which covers the first exhaust hole. This arrangement is conducive to balancing the sealing and exhaust performance of the battery cell.

[0012] According to one embodiment of the present application, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the housing, and the inner surface is disposed toward the inside of the housing; the one-way valve is disposed on the outer surface, and the one-way valve includes a valve body, at least part of which protrudes from the outer surface. This arrangement facilitates the assembly of the one-way valve.

[0013] According to one embodiment of the present application, a second weak zone is provided on the valve body, the actuation pressure of the second weak zone is greater than the valve opening pressure of the one-way valve, and the actuation pressure of the second weak zone is less than the actuation pressure of the first weak zone. This arrangement can achieve the effect of discharging the gas inside the battery cell outward in a hierarchical manner when the internal pressure of the battery cell is too high.

[0014] According to one embodiment of the present application, the valve body has a valve cavity inside, the valve body includes a valve seat and a valve cover, the valve cover includes a cover top wall and a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the valve seat enclose a valve cavity, and the second strength weak area is arranged on the cover side wall. Through this arrangement, the damage to the battery housing caused by the rupture of the valve body can be reduced.

[0015] According to one embodiment of the present application, the second weak strength area includes a plurality of third grooves arranged on the side wall of the cover. Through this arrangement, the damage to the battery housing caused by the rupture of the valve body can be reduced.

[0016] According to one embodiment of the present application, the one-way valve includes a valve body and a valve core, the valve body has a valve cavity inside, the valve body is provided with an air inlet and an air outlet, the air inlet is used to connect the valve cavity with the inside of the shell, and the air outlet is used to connect the valve cavity with the outside of the shell; the valve core is arranged in the valve cavity, the valve core is used to block the air inlet, and the valve core is configured to open the air inlet under the action of the gas inside the shell and release the gas inside the battery cell. This arrangement is conducive to the discharge of gas.

[0017] In one embodiment, the valve body includes a valve seat and a valve cover, the valve cover includes a cover top wall and a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the valve seat enclose a valve cavity, the valve seat is provided with an air inlet, and the valve cover is provided with an air outlet. In this way, the gas is discharged easily.

[0018] In one embodiment, the valve seat has a first through hole penetrating the valve seat, and the gas inlet is the first through hole. In this way, the gas is easily discharged.

[0019] In one embodiment, the cover side wall has a second through hole penetrating the cover side wall, and the gas outlet is the second through hole. In this way, the gas is easily discharged.

[0020] In one embodiment, the second through hole extends to the end of the cover side wall in a direction away from the cover top wall; in this way, the discharge of gas is facilitated.

[0021] In one embodiment, there are a plurality of second through holes, and the plurality of second through holes are spaced apart and distributed in the circumferential direction of the side wall. In this way, the discharge of gas is facilitated.

[0022] In one embodiment, a first guide column is protruded on one side of the cover top wall facing the valve seat, a third through hole penetrating the cover top wall and the first guide column is provided on the cover top wall, or a third through hole penetrating the cover top wall is provided on the cover top wall, and the gas outlet is the third through hole. In this way, the gas discharge is facilitated.

[0023] In one embodiment, the valve cover further comprises a flange wall, the cover side wall connects the cover top wall and the flange wall, the flange wall extends toward a side away from the valve cavity relative to the cover side wall, and the flange wall is connected to the valve seat. In this way, the assembly of the one-way valve is facilitated.

[0024] In one embodiment, a first recessed groove is provided on the side of the valve seat facing the valve cover, which is recessed relative to the surface of the valve seat, and at least a portion of the flange wall is accommodated in the first recessed groove and connected to the valve seat. In this way, the connection strength can be improved and the installation height of the one-way valve can be reduced.

[0025] In one embodiment, the surface of the flange wall facing the cover top wall is flush with the surface of the valve seat facing the valve cover; or the surface of the flange wall facing the cover top wall is lower than the surface of the valve seat facing the valve cover. In this way, the installation height of the one-way valve can be reduced.

[0026] In one embodiment, the flange wall is welded to the valve seat, wherein, in the circumferential direction of the cover side wall, at least a portion of the first weld mark between the flange wall and the valve seat is staggered with the second through hole on the cover side wall. In this way, the damage to the valve core component caused by the high temperature of the welding process can be reduced.

[0027] In one embodiment, the valve core includes an elastic member and a blocking member, wherein the elastic member is disposed in the valve cavity; the blocking member is movably disposed in the valve cavity, and the blocking member is used to block the air inlet under the action of the elastic member, and is used to open the air inlet under the action of the gas inside the housing. In this way, the discharge of gas can be facilitated.

[0028] In one embodiment, the blocking member includes a pressing portion and a sealing portion. Along the thickness direction of the wall portion, two ends of the elastic member are respectively against the valve cover and the pressing portion. The sealing portion is connected to the side of the pressing portion away from the valve cover, and the sealing portion is used to block the air inlet. In this way, the elastic force of the elastic member is facilitated to be transmitted to the blocking member, thereby providing sealing of the one-way valve.

[0029] In one embodiment, the first exhaust hole includes a through hole section and a first hole section, the through hole section and the first hole section are arranged along the thickness direction of the wall portion, the through hole section connects the inside of the shell with the outside of the shell, the first hole section is located on the side of the through hole section away from the inside of the shell, the aperture of the first hole section is larger than the aperture of the through hole section, the one-way valve is at least partially accommodated in the first hole section, the valve body of the one-way valve faces the outside of the shell and at least part of the valve body protrudes from the outer surface of the wall portion. In this way, the assembly of the one-way valve can be facilitated.

[0030] In one embodiment, the first hole section includes a hole side surface arranged circumferentially, a first step surface and a second step surface are arranged on the side of the valve seat facing the valve cover, the first step surface is closer to the valve cover than the second step surface, and the outer peripheral surface of the second step is welded to the hole side surface. In this way, the assembly stability can be improved.

[0031] In one embodiment, the wall portion includes a pressure relief mechanism and a pressure relief hole, the pressure relief hole communicates with the inside of the shell and the outside of the shell, the pressure relief mechanism includes a pressure relief sheet, the pressure relief sheet covers the pressure relief hole, the first strength weak area is arranged on the pressure relief sheet, the pressure relief mechanism is configured to actuate and release the internal pressure of the battery cell when the battery cell is thermally runaway, and the actuation pressure of the pressure relief mechanism is greater than the actuation pressure of the first strength weak area. Through this arrangement, when the internal pressure of the battery cell is too high, the gas inside the battery cell can be discharged to the outside in a hierarchical manner.

[0032] The pressure relief sheet is provided with a second exhaust hole, which communicates with the interior of the housing and the exhaust assembly, and the exhaust assembly includes a one-way valve or a breathable membrane assembly, which is provided on the pressure relief sheet and covers the second exhaust hole. This arrangement is conducive to balancing the sealing performance and exhaust performance of the battery cell.

[0033] The wall is provided with a first exhaust hole, the first exhaust hole communicates with the inside of the shell and the outside of the shell, and the exhaust assembly includes a breathable membrane assembly, and the breathable membrane assembly covers the first exhaust hole. This arrangement is conducive to balancing the sealing performance and exhaust performance of the battery cell.

[0034] In one embodiment, the breathable membrane assembly includes a breathable membrane and a connector, the connector is provided with a first breathable hole, the breathable membrane is provided on the connector and covers the first breathable hole, and the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged. This arrangement can improve the connection strength and reduce the risk of deformation of the breathable membrane.

[0035] In one embodiment, the connector has a first annular table surface that is recessed relative to the surface of the connector, the first annular table surface is arranged around the first vent hole, and the vent membrane is arranged on the first annular table surface. In this way, the installation height of the vent membrane assembly is reduced.

[0036] In one embodiment, the breathable membrane assembly further includes a backing member, which is disposed between the breathable membrane and the connecting member; the air permeability rate of the backing member is greater than the air permeability rate of the breathable membrane. By providing the backing member, support can be provided to the breathable membrane, reducing the risk of deformation of the breathable membrane.

[0037] In one embodiment, the connector further has a second annular table surface that is recessed relative to the surface of the connector, the second annular table surface is arranged around the first air hole, and the backing member is arranged on the second annular table surface. In this way, the installation height of the breathable membrane assembly can be reduced.

[0038] In one embodiment, the connecting piece is a metal piece, which can improve the connection strength between the connecting piece and other components.

[0039] In one embodiment, the breathable membrane is arranged on the side of the connector facing the inside of the housing, and the breathable membrane covers the first breathable hole. This arrangement can reduce the damage to the breathable membrane from the external environment.

[0040] In one embodiment, the wall has a first sunken platform that is recessed relative to the surface of the wall, the first sunken platform is arranged around the second exhaust hole, and the breathable membrane assembly is at least partially located on the first sunken platform. In this way, the installation height of the breathable membrane assembly can be reduced.

[0041] In one embodiment, the housing includes a shell and an end cap, wherein a receiving cavity with an opening is formed inside the shell, and the receiving cavity is used to receive the electrode assembly; the end cap closes the opening; wherein the end cap is a wall; or the shell includes a wall; or the wall is a wall located at the top of the housing when the battery cell is in a placed state. In this way, the gas can be discharged easily.

[0042] In order to solve the above technical problems, another technical solution adopted by the present application is to provide a battery, the battery comprising the above battery monomer. The battery has at least the same advantages as the battery monomer.

[0043] In order to solve the above technical problems, another technical solution adopted by the present application is to provide an electric device, which includes the above battery. The electric device has at least the same advantages as the battery.

[0044] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0047] Figure 2 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments;

[0048] Figure 3 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments;

[0049] Figure 4 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments;

[0050] Figure 5 is a front view of a one-way valve according to one or more embodiments;

[0051] Figure 6 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0052] Figure 7 is a state schematic diagram of a one-way valve according to one or more embodiments;

[0053] Figure 8 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments;

[0054] Fig. 9is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0055] Fig.10 is a front view of a one-way valve according to one or more embodiments;

[0056] Fig.11 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

[0057] Fig.12 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments;

[0058] Fig.13 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0059] Fig.14 is a schematic diagram of a cross-sectional structure of a wall portion according to one or more embodiments;

[0060] Fig.15 is a schematic cross-sectional structure diagram of a breathable membrane assembly according to one or more embodiments;

[0061] Fig.16 is a schematic cross-sectional structure diagram of a breathable membrane assembly 40 according to one or more embodiments;

[0062] Fig.17 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments;

[0063] Fig.18 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments;

[0064] Fig.19 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0065] Fig. 20 is a schematic diagram of an exploded structure of a battery according to one or more embodiments;

[0066] Fig.21 is a schematic diagram of the structure of a vehicle according to one or more embodiments.

[0067] In the attached figure:

[0068] 1000, vehicle; 300, motor; 200, controller; 100, battery; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, wall; 21, end cover; 21a, outer surface; 21b, inner surface; 212, first weak area; 212a, first groove; 210, wall body; 210a, sinking part; 291, first vent hole; 292, second vent hole; 22, housing; 23, electrode assembly; 24, insulating member; 25, electrode terminal; 280, through hole section; 281, first hole section; 30, one-way valve; 31, valve body; 311, valve seat; 3111, first through hole; 3112, first sinking groove; 311b, first step surface; 311c, second step surface; 3119, second weak area; 3120, first through hole; 3121, first sinking groove; 3122, first step surface; 3123, second step surface; 3124, second weak area; 3125, second weak area; 3126, first through hole; 3127, first sinking groove; 3128, first step surface; 3129, second weak area; 3130, first through hole; 3131, first sinking groove; 3132, first step surface; 3133, second step surface; 3134, second weak area; 3135, first through hole; 3136, first sinking groove; 3137, first step surface; 3138, second sinking groove; 3139, first step surface; 3140, first step surface; 3141, first step surface; 3142, first step surface; 3143, first step surface; 3144 12. Valve cover; 3121. Top wall of cover; 31211. First guide post; 31212. Third through hole; 3122. Side wall of cover; 31221. Second through hole; 31222. Flanged wall; 31222a. Connecting surface; 313. Valve cavity; 313a. Air inlet; 313b. Air outlet; 32. Valve core; 321. Blocking member; 322. Elastic member; 40. Breathable membrane assembly; 41. Breathable membrane; 42. Metal part; 491. First breathable hole; 43. Backing member; 70. Pressure relief mechanism; 71. Pressure relief sheet; 60. Protective patch; 601. First avoidance hole; 602. Second avoidance hole; 603. Information collection hole; 90. Exhaust assembly; T1. First annular table; T2. Second annular table; T3. Transition surface; S1. First sink; W1. First weld mark. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and effect of the present application clearer and more specific, the following will describe the embodiments of the technical solution of the present application in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0071] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two (including two groups), and "multiple pieces" refers to more than two (including two pieces), unless otherwise clearly and specifically defined.

[0072] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0073] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0074] Amounts, ratios and other numerical values ​​are presented herein in a range format. It should be understood that such a range format is for convenience and brevity and should be flexibly understood to include not only the values ​​explicitly specified as range limits, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0075] In the description of the embodiments of the present application, the same reference numerals 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, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0076] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0077] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0078] Batteries are widely used in the field of new energy, mainly including electric vehicles, energy storage systems and renewable energy. In the field of electric vehicles, higher performance such as longer driving range and fast charging are gradually achieved. In terms of energy storage systems, batteries are widely used in large-scale and distributed energy storage. They can balance the load of the grid, store renewable energy such as solar and wind power, and release the stored energy during peak hours. In addition, small rechargeable batteries are also widely used in applications such as wearable devices, drones and smart homes.

[0079] As the battery cells are charged and discharged, some side reactions will produce gas. If the gas produced by the battery cells is not discharged in time, the internal pressure of the battery cells will increase. Excessive internal pressure will have a negative impact on the performance and appearance of the battery cells. For example, in severe cases, it will have a destructive effect on the performance and appearance of the battery cells, such as leakage, bulging, increased internal resistance of the battery cells, and shortened discharge time and cycle life. In addition, there are some abnormal operations of the battery cells during use, including overcharging, over-discharging, internal failures, etc. In this case, the chemical reaction inside the battery cells may be uncontrolled, accompanied by violent release of gas, and even cause thermal runaway of the battery cells. Thermal runaway of battery cells refers to a chain reaction phenomenon caused by various inducements. The large amount of heat and harmful gases emitted by thermal runaway can cause the battery cells to catch fire and explode.

[0080] Based on the above considerations, an embodiment of the present application provides a battery cell, on which an exhaust assembly is provided. The exhaust assembly can be used to exhaust the gas inside the battery cell in a timely manner to maintain a stable internal pressure of the battery cell.

[0081] Please refer to Figure 1 , Figure 1 FIG. 2 is a schematic diagram of the exploded structure of a battery cell according to one or more embodiments. A battery cell 20 is the smallest unit that constitutes a battery. Figure 1 The battery cell 20 includes an end cover 21, a shell 22, an electrode assembly 23 and other functional components.

[0082] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals 25 can be provided on the end cap 21. The electrode terminal 25 can be used to electrically connect with the electrode assembly 23 for outputting or inputting the electrical energy of the battery cell 20. Exemplarily, the battery cell 20 is provided with two electrode terminals 25, and the two electrode terminals 25 are both installed on the end cap 21, and the two electrode terminals 25 are respectively used to electrically connect with the two pole ears of opposite polarity of the electrode assembly 23 to realize the output or input of the positive and negative electrodes of the battery cell 20 respectively. The material of the end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the present embodiment. In some embodiments, an insulating member 24 can be provided on the inner side of the end cap 21, and the insulating member 24 can be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. Exemplarily, the insulating member can be plastic, rubber, etc.

[0083] The shell 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, the electrolyte and other components. The shell 22 and the end cap 21 can be independent components, and an opening can be set on the shell 22, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 21 at the opening. Without limitation, the end cap 21 and the shell 22 can also be integrated. Specifically, the end cap 21 and the shell 22 can form a common connection surface before other components are put into the shell, and when the interior of the shell 22 needs to be encapsulated, the end cap 21 covers the shell 22. The shell 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0084] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be included in the housing 22. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a lug. The positive electrode lug and the negative electrode lug may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the lugs connect the electrode terminals to form a current loop.

[0085] Please refer to Figure 1 and Figure 2 , Figure 2 Schematic diagram of partial decomposition structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the present application discloses a battery cell 20, the battery cell 20 includes a shell and an exhaust assembly 90, the shell has a wall portion 21, the exhaust assembly 90 is arranged on the wall portion 21, the exhaust assembly 90 includes a one-way valve 30 and / or a breathable membrane assembly 40, the breathable membrane assembly 40 includes a breathable membrane 41, and the exhaust assembly 90 is used to exhaust the gas inside the shell; a first strength weak area 212 is arranged on the wall portion 21, and the first strength weak area 212 is arranged along the circumference of the exhaust assembly 90.

[0086] Among them, the exhaust component 90 includes the one-way valve 30 and / or the breathable membrane component 40, which means that the exhaust component 90 can include the one-way valve 30 alone, or the exhaust component 90 can include the breathable membrane component 40 alone, or the exhaust component 90 can include both the one-way valve 30 and the breathable membrane component 40; when the exhaust component 90 includes both the one-way valve 30 and the breathable membrane component 40, the one-way valve 30 and the breathable membrane component 40 can be arranged in series, that is, when the gas is discharged through the one-way valve 30, it also flows through the breathable membrane component 40; the one-way valve 30 and the breathable membrane component 40 can also be arranged in parallel, that is, the gas can be discharged through the one-way valve 30 and the breathable membrane component 40 respectively. Figure 1 The exhaust assembly 90 includes a one-way valve 30. By providing the exhaust assembly 90 on the battery cell 20, the gas inside the battery cell 20 can be discharged to the outside of the outer shell of the battery cell 20 in time, so that the gas pressure inside the battery cell 20 is maintained within a normal level, the safety performance of the battery cell 20 can be improved, and the life of the battery cell 20 can be greatly increased.

[0087] The first weak strength area 212 refers to an area with relatively low strength relative to other areas of the wall 21. If the wall 21 is affected by some factors such as external force, it is easy to be damaged by fracture or the like at the first weak strength area 212. By setting the first weak strength area 212 on the battery cell 20, when the internal pressure of the battery cell 20 is too high or the temperature reaches a threshold, the wall 21 can be broken at the first weak strength area 212 to timely release the pressure inside the battery cell 20. In other words, the solution provided by the present application is to set the exhaust assembly 90 on the battery cell 20, and the gas generated inside the shell of the battery cell 20 during the normal use of the battery cell 20 can be discharged through the exhaust assembly 90, and when thermal runaway or excessive internal pressure occurs inside the battery cell 20, the wall 21 of the battery cell 20 can be broken at the first weak strength area 212 to release the gas inside the battery cell 20.

[0088] In one embodiment, the first weak strength area 212 includes a first thickness weak area. That is, the thickness of this area may be relatively thinner than other areas of the wall portion 21, and the strength is reduced by reducing the thickness. In other embodiments, the first weak strength area 212 may be constructed by selecting materials with different strengths, such as selecting some materials with relatively low strength to form the first weak strength area 212.

[0089] According to some embodiments of the present application, the outer shell includes an end cover 21 and a shell 22, and the wall portion may be a wall of the end cover 21 or a wall of the shell 22. That is, the exhaust assembly 90 may be disposed on the end cover 21 or on the shell 22. In other words, the wall portion for mounting the exhaust assembly 90 may be the end cover 21 of the outer shell or a wall of the shell 22 of the outer shell. Exemplarily, the wall portion is the end cover 21. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the wall portion may also be a bottom wall of the shell 22 and the end cover 21, and the wall portion may also be a side wall of the shell 22 and the end cover 21 that are adjacent to and connected to each other. The following will take the wall portion as the wall of the end cover 21 as an example to illustrate the present application, but this should not limit the present application.

[0090] Please refer to Figure 1 , Figure 2 and Figure 3 , Figure 3 2 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. In one embodiment, the first weak strength area 212 includes a first groove 212a that is recessed relative to the surface of the wall portion 21, and the first groove 212a is arranged around the exhaust assembly 90. By arranging the first groove 212a on the wall portion 21, the thickness of the wall portion 21 in the area where the first groove 212a is located can be reduced, so that the thickness of the wall portion 21 in the area is weakened, and the strength of the wall portion 21 in the area is weakened.

[0091] like Figure 2 As shown, the first groove 212a may be an annular groove surrounding the exhaust assembly 90, and the first groove 212a may be a notched groove formed by etching or the like. In other embodiments, the first groove 212a may also be a non-closed annular groove, that is, the first groove 212a may not necessarily be completely closed in the circumferential direction, and may also be a groove of two-thirds of a circle, or a groove of three-quarters of a circle.

[0092] In one embodiment, the first weak strength area 212 includes a plurality of second grooves (not shown) that are recessed relative to the surface of the wall portion 21, and the plurality of second grooves are arranged at intervals in the circumferential direction of the exhaust assembly 90. In other words, the annular first groove can be interrupted and divided into a plurality of second grooves. In this embodiment, the thickness of the wall portion 21 in this area can be weakened by providing non-continuous grooves, thereby achieving the weakened strength of the wall portion 21 in this area.

[0093] In one embodiment, the first weak area further includes a notch 212b disposed at the bottom of the first groove 212a and / or the second groove. Figure 3 As shown, the bottom of the first groove 212a is provided with a notch 212b. By this arrangement, the strength of the first groove 212a can be further reduced, which is conducive to the wall portion 21 being damaged at this location.

[0094] Please refer to Figure 4 , Figure 4 2 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. In one embodiment, the wall portion 21 has an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a is disposed toward the outside of the housing, and the inner surface 21b is disposed toward the inside of the housing; the first groove 212a is recessed relative to the outer surface 21a of the wall portion 21; and / or the first groove 212a is recessed relative to the inner surface 21b of the wall portion 21.

[0095] The first groove 212a may be provided on both the inner and outer sides of the wall portion 21; the first groove 212a may be provided only on the outer surface 21a of the wall portion 21; or the first groove 212a may be provided only on the inner surface 21b of the wall portion 21. Figure 4As shown, the first groove 212a is provided on one side of the outer surface 21a and one side of the inner surface 21b of the wall portion 21. When the first groove 212a is provided on both sides, the orthographic projections of the first grooves 212a on both sides on the wall portion 21 can be set to at least partially overlap. Through this arrangement, the thickness of the wall portion 21 can be thinned from both sides, and the thickness of the wall portion 21 where the first groove 212a is provided is reduced to achieve a weak thickness in this area. When the internal pressure of the battery cell 20 is too large, the wall portion 21 is more likely to break at the first groove 212a. Among them, when the first groove 212a is provided on both the inner and outer sides of the wall portion 21, the notch 212b can be provided only at the bottom of the first groove 212a on one side. Of course, the notch 212b can also be provided at the bottom of the first grooves 212a on both sides. As shown Figure 4 As shown, a notch 212 b is provided at the bottom of the first groove 212 a located outside the wall portion 21 .

[0096] Please continue to refer to Figure 4 The wall portion 21 includes a wall body 210 and a sinking portion 210a. The wall body 210 has an outer surface 21a and an inner surface 21b that are arranged opposite to each other. The outer surface 21a is arranged toward the outside of the shell, and the inner surface 21b is arranged toward the inside of the shell. The sinking portion 210a is connected to the wall body 210, and the sinking portion 210a protrudes from the inner surface 21b. The first strength weak area 212 is arranged on the sinking portion 210a.

[0097] The wall portion 21 may be punched to form a concave sinking portion 210a. This arrangement can reduce the strength of the region after punching, and reduce the space occupied by the exhaust assembly 90 in the height direction of the battery cell 20.

[0098] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 In one embodiment, the wall portion 21 is provided with a first exhaust hole 291, and the first exhaust hole 291 connects the inside of the shell with the outside of the shell, and the exhaust component 90 includes a one-way valve 30, and the one-way valve 30 covers the first exhaust hole 291. In this embodiment, the one-way valve 30 is used as the exhaust component 90, which opens the valve to release air when the internal pressure of the battery cell 20 reaches a predetermined pressure. As the internal pressure of the battery cell 20 decreases, the one-way valve 30 is closed again to achieve the sealing of the battery cell 20. In other words, when the one-way valve 30 is used to exhaust, it is actually intermittent exhaust. In this way, the battery cell 20 does not need to be in the exhaust state all the time, and the sealing of the battery cell 20 is maintained to reduce the intrusion of external water vapor.

[0099] In one embodiment, at least a portion of the one-way valve 30 is accommodated in the first exhaust hole 291 .

[0100] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 In one embodiment, the wall portion 21 has an outer surface 21a and an inner surface 21b that are disposed opposite to each other, the outer surface 21a is disposed toward the outside of the housing, and the inner surface 21b is disposed toward the inside of the housing; the one-way valve 30 is disposed on the outer surface 21a, and the one-way valve 30 includes a valve body 31, and at least a portion of the valve body 31 protrudes from the outer surface 21a. This arrangement facilitates the assembly of the one-way valve 30.

[0101] Please refer to Figure 5 and Figure 6 , Figure 5 is a front view of a one-way valve according to one or more embodiments. Figure 6 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. In one embodiment, a second weak area 3119 is provided on the valve body 31 of the one-way valve 30, and the actuation pressure of the second weak area 3119 is greater than the valve opening pressure of the one-way valve 30, and the actuation pressure of the second weak area 3119 is less than the actuation pressure of the first weak area 212.

[0102] Among them, the actuating pressure of the first strength weak zone 212 refers to the pressure that can cause the wall portion 21 to break from the first strength weak zone 212; similarly, the actuating pressure of the second strength weak zone 3119 refers to the pressure that can cause the one-way valve 30 to break from the second strength weak zone 3119.

[0103] In some embodiments, the actuation pressure of the second weak area 3119 is greater than the opening pressure of the one-way valve 30, that is, the pressure of the gas inside the battery cell 20 shell that causes the one-way valve 30 to break from the second weak area 3119 is greater than the pressure of the gas inside the shell to open the one-way valve 30. When the pressure inside the battery cell 20 is too high or thermal runaway occurs, the gas inside the shell of the battery cell 20 will increase rapidly to break through the valve body 31 of the one-way valve 30 (such as Figure 7 As shown, Figure 7 2 is a schematic diagram of the state of the one-way valve according to one or more embodiments) to release pressure, and when the gas generated inside the shell 21 of the battery cell 20 during normal use reaches a threshold, the one-way valve 30 can be opened, but the valve body 31 of the one-way valve 30 cannot be broken.

[0104] The actuation pressure of the second weak strength area 3119 is less than the actuation pressure of the first weak strength area 212, that is, the pressure of the gas inside the shell of the battery cell 20 causing the one-way valve 30 to break from the second weak strength area 3119 is less than the pressure of the gas inside the shell causing the wall 21 to break from the first weak strength area 212. When the pressure inside the battery cell 20 is too high or thermal runaway occurs, the gas inside the shell of the battery cell 20 will increase rapidly and will first break through the valve body 31 of the one-way valve 30 to release pressure. If the pressure relief requirement is still not met, it may further break through the wall 21 to release pressure as the pressure increases. When the gas generated inside the shell 21 of the battery cell 20 during normal use reaches a threshold, the one-way valve 30 can be opened, but it cannot break through the valve body 31 and the wall 21 of the one-way valve 30.

[0105] This setting is equivalent to designing a multi-level control valve. When the battery cell 20 is in normal use, the one-way valve 30 is used to exhaust gas. At this time, the one-way valve 30 and the wall 21 are both intact; if the internal air pressure of the battery cell 20 suddenly increases and the pressure is too high, the valve body 31 of the one-way valve 30 can be broken through to release the pressure first. At this time, the wall 21 is intact; if the pressure still cannot be significantly released, as the pressure increases, the wall 21 can continue to be broken through to release the pressure. Through the multi-level setting, the gas inside the shell can be discharged to the outside of the shell in time, so that the air pressure inside the shell is not too high, reducing the risk of premature damage to the wall 21, and greatly improving the life of the battery cell 20.

[0106] In some embodiments, the interior of the valve body 31 has a valve cavity 313, the valve body 31 includes a valve seat 311 and a valve cover 312, the valve cover 312 includes a cover top wall 3121 and a cover side wall 3122 connected to the cover top wall 3121, the cover top wall 3121, the cover side wall 3122 and the valve seat 311 enclose a valve cavity 313, and a second strength weak area 3119 is set on the cover side wall 3122.

[0107] In some embodiments, the second weak zone 3119 includes a plurality of third grooves 3119 a disposed on the cover side wall 3122 .

[0108] By providing the third groove 3119a on the cover side wall 3122, the thickness of the cover side wall 3122 in the area where the third groove 3119a is located can be reduced, so that the thickness of the area is weakened, and then the strength of the area is weakened.

[0109] In one embodiment, the third groove 3119a is located on the side of the cover side wall 3122 facing the valve cavity 313; and / or the third groove 3119a is located on the side of the cover side wall 3122 away from the valve cavity 313. In other words, the third groove 3119a can be provided on both the inner and outer sides of the cover side wall 3122. The third groove 3119a can also be provided only on the inner side of the cover side wall 3122, or the third groove 3119a can also be provided only on the outer side of the cover side wall 3122. When the third groove 3119a is provided on both the inner and outer sides, the orthographic projections of the third grooves 3119a on both sides on the cover side wall 3122 can be provided to at least partially overlap. Through this arrangement, the thickness of the cover side wall 3122 can be reduced from both sides, and the thickness of the cover side wall 3122 where the third groove 3119a is provided can be reduced, so that the thickness is thin and it is easier to break when under pressure.

[0110] In one embodiment, the cover side wall 3122 has a second through hole 31221 penetrating the cover side wall 3122, and the third groove 3119a is disposed on the connecting arm between two adjacent second through holes 31221. There may be a plurality of second through holes 31221, and the plurality of second through holes 31221 are disposed at intervals in the circumferential direction of the cover side wall 3122. The provision of the second through holes 31221 can cause a part of the cover side wall 3122 to be physically missing, which reduces the strength of the cover side wall 3122 to a certain extent. On this basis, the third groove 3119a is provided to make the wall portion 21 more likely to break when under pressure.

[0111] like Figure 5 As shown, a third groove 3119a may be provided on the connecting arm between two adjacent second through holes 31221. The third groove 3119a may extend along the circumference of the valve cover 312 and may extend to both ends of the connecting arm.

[0112] In one embodiment, the second area of ​​weakness 3119 includes a first score groove, which is a circumferential groove surrounding the cover side wall 3122.

[0113] like Figure 5 As shown, due to the provision of the second through hole 31221, in the axis Y direction of the valve cavity 313, the cover side wall 3122 includes a solid area 3122a and an exhaust area 3122b. In the circumferential direction of the valve cavity 313, the second through hole 31221 is provided on the cover side wall 3122 of the exhaust area 3122b, and the cover side wall 3122 is discontinuous, while the cover side wall 3122 of the solid area 3122a is a continuous solid structure, therefore, a second strength weak area 3119 may also be provided on the cover side wall 3122 of the solid area 3122a. Specifically, the second strength weak area 3119 includes a first notch groove, which is a circumferential groove on the cover side wall 3122.

[0114] In other embodiments, discontinuous grooves may be provided on the circumference of the cover side wall 3122. Specifically, the second weak strength area 3119 includes a plurality of second notched grooves, which are arranged at intervals on the circumference of the cover side wall 3122. That is, a plurality of discontinuous grooves may be provided on the cover side wall 3122 of the solid area 3122a.

[0115] Please refer to Figure 3 , Figure 4 and Figure 6 The one-way valve 30 in the present application may not include the second weak strength area 3119, or may include the second weak strength area 3119. It can be selected as needed. In some embodiments, two types of one-way valves 30 may be provided on one battery cell 20 at the same time.

[0116] Please refer to Figure 1 and Figure 2 The wall portion 21 with the first weak area 212 can relieve pressure to a certain extent, and the one-way valve 30 with the second weak area 3119 can also relieve pressure. Therefore, when this structure is selected, the battery cell 20 may not be provided with a pressure relief mechanism. Of course, when the wall portion 21 with the first weak area 212 and the one-way valve 30 with the second weak area 3119 are selected, the battery cell 20 may also be provided with a pressure relief mechanism at the same time.

[0117] Please refer to Figure 8 and Fig. 9 , Figure 8 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments. Fig. 9 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. In one embodiment, the wall portion 21 includes a pressure relief mechanism 70 and a pressure relief hole 701, the pressure relief hole 701 communicates with the inside of the shell and the outside of the shell, the pressure relief mechanism 70 includes a pressure relief sheet 71, the pressure relief sheet 71 covers the pressure relief hole 701, the first strength weak area 212 is provided on the pressure relief sheet 71, the pressure relief mechanism 70 is configured to actuate and release the internal pressure of the battery cell 20 when the battery cell 20 is in thermal runaway, and the actuation pressure of the pressure relief mechanism 70 is greater than the actuation pressure of the first strength weak area 212.

[0118] The actuation pressure of the pressure relief mechanism 70 is set to be greater than the actuation pressure of the first weak strength zone 212. With this setting, when the battery cell 20 has thermal runaway, the gas inside the shell of the battery cell 20 will increase rapidly to open the pressure relief mechanism 70 for pressure relief. The gas generated inside the shell 21 of the battery cell 20 during normal use can be discharged through the exhaust assembly, but the pressure relief mechanism 70 cannot be opened. Furthermore, when thermal runaway occurs, before opening the pressure relief mechanism 70, the exhaust assembly can be destroyed at the first weak strength zone 212 to relieve pressure to a certain extent. If the gas pressure inside the battery cell 20 still increases, the pressure relief mechanism 70 can be opened again.

[0119] In one embodiment, the pressure relief sheet 71 is provided with a second exhaust hole 292, which communicates with the interior of the housing and the exhaust assembly 90, and the exhaust assembly 90 includes a breathable membrane assembly 40, which is provided on the pressure relief sheet 71 and covers the second exhaust hole 292. Through this arrangement, the gas generated inside the housing 21 of the battery cell 20 during normal use can be discharged through the breathable membrane assembly 40. In the event of thermal runaway, before opening the pressure relief mechanism 70, the breathable membrane assembly 40 can be first destroyed at the first strength weak area 212 to relieve pressure to a certain extent. If the internal air pressure of the battery cell 20 still increases, the pressure relief mechanism 70 can be opened to relieve pressure.

[0120] According to some embodiments of the present application, when the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a of the wall, and at least part of the valve body 31 protrudes from the outer surface 21a, that is, the one-way valve 30 is arranged on the side of the wall facing the outside of the shell, a variety of one-way valves 30 with different structures can be set.

[0121] Please refer to Fig.10 , Fig.11 , Fig.12 and Fig.13 , Fig.10 is a front view of a one-way valve according to one or more embodiments; Fig.11 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments; Fig.12 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments; Fig.13 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. In one embodiment, the valve body 31 includes a valve seat 311 and a valve cover 312. The valve cover 312 includes a cover top wall 3121 and a cover side wall 3122 connected to the cover top wall 3121. The cover top wall 3121, the cover side wall 3122 and the valve seat 311 enclose a valve cavity 313. The valve seat 311 is provided with an air inlet 313a, and the valve cover 312 is provided with an air outlet 313b. In this way, the gas is discharged easily.

[0122] In this embodiment, the valve body 31 of the one-way valve 30 is provided with a valve seat 311 and a valve cover 312. The one-way valve 30 with this structure is provided with the valve body 31 as two parts, so that it is convenient to assemble the valve core 32 into the valve cavity 313, which is helpful to reduce the difficulty of assembling the one-way valve 30.

[0123] According to some embodiments of the present application, the valve seat 311 has a first through hole 3111 penetrating the valve seat 311, and the air inlet 313a is the first through hole 3111, that is, the first through hole 3111 serves as the air inlet 313a of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0124] According to some embodiments of the present application, the cover sidewall 3122 has a second through hole 31221 penetrating the cover sidewall 3122, and the gas outlet 313b is the second through hole 31221, that is, the second through hole 31221 is used as the gas outlet 313b of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0125] According to some embodiments of the present application, along a direction away from the cover top wall 3121 , the second through hole 31221 extends to an end of the cover side wall 3122 .

[0126] like Fig.11 As shown, the direction away from the cover top wall 3121 is the direction from the cover top wall 3121 to the valve seat 311 (X direction in the figure), and the second through hole 31221 is formed by removing part of the structure of the cover side wall 3122. Along the X direction, the cover side wall 3122 is directly hollowed out to the bottom end of the cover side wall 3122.

[0127] In one embodiment, along the axial direction of the valve cavity 313 (the Y direction in the figure), the sealing interface between the valve core 32 and the valve seat 311 is higher than or flush with the bottom wall of the second through hole 31221. In the X direction, the lower opening surface of the second through hole 31221 can be flush with the sealing surface between the blocking member 321 and the valve seat 311, that is, the sealing interface is higher than or flush with the bottom wall of the second through hole 31221. The so-called bottom wall of the second through hole 31221 refers to the lowest point of the second through hole 31221, such as Fig.11 At the position indicated by the middle arrow P, along the X direction, the lower opening surface of the second through hole 31221 is the bottom wall of the second through hole 31221. Through this arrangement, when the one-way valve 30 is opened for exhaust, that is, when the blocking member 321 opens the sealing interface, the electrolyte liquid brought out with the gas can be discharged outward in time, so that the electrolyte is not easy to accumulate on the outer edge of the blocking member 321, thereby effectively ensuring the sealing and repeated opening function of the one-way valve 30.

[0128] According to some embodiments of the present application, there are multiple second through holes 31221, and the multiple second through holes 31221 are spaced apart in the circumferential direction of the cover side wall 3122. Through this arrangement, when the one-way valve 30 is opened for exhaust, the gas can be exhausted more quickly, and the exhaust time can be shortened, that is, the time when the battery cell 20 shell is in an open state can be shortened, so as to reduce the invasion of external water vapor into the battery cell 20 system during the valve opening period.

[0129] Please refer to Fig.12 According to some embodiments of the present application, a first guide column 31211 is protruded from the side of the cover top wall 3121 facing the valve cavity 313, and a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121 and the first guide column 31211, or a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121, and the air outlet 313b is the third through hole 31212.

[0130] Specifically, a first guide column 31211 is convexly provided on one side of the cover top wall 3121 facing the valve cavity 313, and a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121 and the first guide column 31211, and the gas outlet 313b is the third through hole 31212. That is, the third through hole 31212 is used as the gas outlet 313b of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0131] Please continue to refer to Fig.10 , Fig.11 , Fig.12 and Fig.13 According to some embodiments of the present application, the valve cover 312 also includes a flange wall 31222, the cover side wall 3122 connects the cover top wall 3121 and the flange wall 31222, the flange wall 31222 extends toward a side away from the valve cavity 313 relative to the cover side wall 3122, and the flange wall 31222 is connected to the valve seat 311.

[0132] According to some embodiments of the present application, the valve cover 312 is connected to the valve seat 311. Specifically, a first recessed groove 3112 is provided on the side of the valve seat 311 facing the valve cover 312, and at least a portion of the flange wall 31222 is accommodated in the first recessed groove 3112 and connected to the valve seat 311.

[0133] In this embodiment, a first recess 3112 is provided on the side of the valve seat 311 facing the valve cover 312, and at least a portion of the flange wall 31222 is accommodated in the first recess 3112. The one-way valve 30 adopting such a structure can save the space occupied by the valve body 31 in the thickness direction of the end cover 21 on the one hand, and can improve the structural stability of the valve cover 312 assembled on the valve seat 311 on the other hand.

[0134] According to some embodiments of the present application, the flange wall 31222 is accommodated in the first sink 3112 and connected to the valve seat 311. The thickness of the flange wall 31222 is less than or equal to the depth of the first sink 3112, so that after the flange wall 31222 is connected to the valve seat 311, the surface of the flange wall 31222 facing the cover top wall 3121 is flush with the surface of the valve seat 311 facing the valve cover 312; or the surface of the flange wall 31222 facing the cover top wall 3121 is lower than the surface of the valve seat 311 facing the valve cover 312. Fig.12 and Fig.13 As shown, after the valve cover 312 is connected to the valve seat 311, the flange wall 31222 is flush with the surface of the valve seat 311. This arrangement can reduce the overall installation height of the one-way valve 30.

[0135] According to some embodiments of the present application, the material of the valve seat 311 may be a metal material, such as copper, iron, aluminum, steel or aluminum alloy. Similarly, the material of the valve cover 312 may also be a metal material, such as copper, iron, aluminum, steel or aluminum alloy. The valve seat 311 and the valve cover 312 may be made of the same material or different materials. The valve cover 312 and the valve seat 311 may be assembled by welding (such as laser welding); they may also be assembled by mechanical interference, but the static friction generated by the interference must be greater than the rebound force of the elastic member 322.

[0136] According to some embodiments of the present application, the flange wall 31222 is welded to the valve seat 311 ; wherein, in the circumferential direction of the cover side wall 3122 , at least a portion of the first weld mark W1 between the flange wall 31222 and the valve seat 311 is staggered with the second through hole 31221 on the cover side wall 3122 .

[0137] The flange wall 31222 is an annular component with a certain thickness, and the outer peripheral surface of the flange wall 31222 is used as a connecting surface 31222a to be welded to the groove wall surface of the first sink groove 3112. Further, the connecting surface 31222a of the flange wall 31222 can be set as an inclined surface, and the groove wall surface of the first sink groove 3112 can also be set as an inclined surface accordingly, so that the connecting surface 31222a of the flange wall 31222 fits with the groove wall surface of the first sink groove 3112, as shown in FIG. Fig.12 and Fig.13 As shown, the flange wall 31222 and the first sink 3112 may form an interlocking structure. In this way, the welding quality can be improved, and the strength and stability of the connection can be enhanced. Furthermore, the valve cover 312 and the valve seat 311 are preferably made of the same material to achieve better welding quality.

[0138] According to some embodiments of the present application, in the circumferential direction of the cover side wall 3122, at least a portion of the first weld mark W1 where the flange wall 31222 is welded to the valve seat 311 is staggered with the second through hole 31221. Fig.10 As shown, welding can be performed at a position on the cover side wall 3122 where no second through hole 31221 is opened. There can be multiple first weld marks W1, and the multiple first weld marks W1 are distributed in the circumferential direction of the cover side wall 3122. The distribution of the first weld marks W1 can be staggered with the distribution of the second through holes 31221. In other words, multiple second through holes 31221 are spaced apart in the circumferential direction of the cover side wall 3122, and the position without openings between adjacent second through holes 31221 has a solid wall, and welding is performed at a place with a solid wall. The first weld mark W1 in this article expresses the welding site or welding position between the flange wall 31222 and the valve seat 311, and does not mean that there must be a welding mark in the actual product. Whether there is a mark is different from the welding process, and it should not be limited to the presence of a mark. In this way, the solid wall has a certain heat-blocking effect, which can protect the sealing part 321 of the valve core 32 and reduce the impact of high temperature during welding on the sealing part 321, so as to prevent the sealing part 321 from being deformed by heat, thereby causing failure of the sealing interface when the valve is not opened.

[0139] According to some embodiments of the present application, the valve core 32 may include an elastic member 322 and a sealing member 321, the elastic member 322 is arranged in the valve cavity 313, the sealing member 321 is movably arranged in the valve cavity 313, and the sealing member 321 is used to block the air inlet under the action of the elastic member 322, and is used to open the air inlet under the action of the gas inside the shell.

[0140] Specifically, the elastic member 322 is disposed in the valve cavity 313 , the blocking member 321 is movably disposed in the valve cavity 313 , the elastic member 322 is configured to provide elastic force to the blocking member 321 , and the sealing and opening of the valve cavity 313 are achieved by deformation of the elastic member 322 .

[0141] Among them, the blocking member 321 is movably arranged in the valve cavity 313, that is, the blocking member 321 can move in the valve cavity 313, so that the blocking member 321 can block the air inlet 313a when it moves close to the air inlet 313a, and conversely, the blocking member 321 can open the air inlet 313a when it moves away from the air inlet 313a.

[0142] In some embodiments, the blocking member 321 is gap-matched with the inner wall of the valve cavity 313 .

[0143] Optionally, the elastic member 322 is an elastic member, and its structure can be various, such as a spring, a spring or an elastic rubber. Exemplarily, the elastic member 322 is a spring. Using a spring as the elastic member arranged in the valve cavity, on the one hand, facilitates the assembly of the elastic member, which helps to reduce the difficulty of assembling the elastic member in the valve cavity, and on the other hand, it can achieve a more stable direction in which the elastic force applied by the elastic member to the blocking member. In some embodiments, the material of the elastic member includes steel, iron or aluminum. The elastic member made of steel, iron or aluminum has good toughness, and can alleviate the phenomenon of elastic failure of the elastic member, which helps to increase the service life of the elastic member.

[0144] In some embodiments, the blocking member 321 is used to block the air inlet 313a under the action of the elastic member 322, and is used to open the air inlet 313a under the action of the gas inside the shell. That is, the elastic member 322 can provide elastic force for the blocking member 321, so that the blocking member 321 can abut against the bottom surface of the valve cavity 313 to block the air inlet 313a. Conversely, when the force of the gas inside the shell on the blocking member 321 is greater than the elastic force of the elastic member 322, the gas inside the shell can overcome the elastic force of the elastic member 322 and push the blocking member 321 to separate from the bottom surface of the valve cavity 313, so as to enable the blocking member 321 to open the air inlet 313a, so that the gas inside the shell can enter the valve cavity 313 through the air inlet 313a and then be discharged through the air outlet 313b.

[0145] Furthermore, the blocking member 321 includes a clamping portion 3212 and a sealing portion 3211. Along the axial direction of the valve cavity 313, two ends of the elastic member respectively abut against the valve cover and the clamping portion. The sealing portion is connected to the side of the clamping portion away from the valve cover, and the sealing portion is used to block the air inlet channel.

[0146] Among them, the rigidity of the clamping part 3212 is greater than that of the sealing part 3211, the sealing part 3211 is connected to the side of the clamping part 3212 away from the top wall 3121 of the cover, the sealing part 3211 is used to seal the air inlet 313a, and the elastic member 322 is arranged between the top wall 3121 of the cover and the clamping part 3212. The clamping part 3212 can be pressed on the sealing part 3211 under the elastic force of the elastic member 322, so that the upper surface of the sealing part 3211 is effectively in contact with the clamping part 3212, so that the sealing part 3211 is against the bottom surface of the valve cavity 313, thereby sealing the air inlet 313a through the sealing part 3211.

[0147] According to some embodiments of the present application, the rigidity of the pressing portion 3212 is greater than the rigidity of the sealing portion 3211, and the setting of the pressing portion 3212 can effectively transmit the force applied by the elastic member to the sealing portion 3211. In other words, the rigidity of the pressing portion is greater than the rigidity of the sealing portion, that is, the deformation resistance of the pressing portion is greater than the deformation resistance of the sealing portion, so that the pressing portion can better press the sealing portion onto the bottom surface of the installation cavity to block the air inlet. Exemplarily, the material of the pressing portion can be various, such as steel, iron or aluminum. Similarly, the material of the sealing portion can also be various, such as rubber, silicone or plastic.

[0148] Optionally, the connection structure between the pressing portion and the sealing portion may be various, such as clamping, bolting, or bonding.

[0149] By configuring the sealing member to include two parts, a pressing portion and a sealing portion, the pressing portion is arranged on the side of the sealing portion facing the valve cover, the sealing portion is used to seal the air inlet, and the two ends of the elastic member are respectively against the valve cover and the pressing portion, so that the elastic member can exert an elastic force on the sealing portion through the pressing portion, which is beneficial to improving the balance of the elastic force of the elastic member acting on the sealing portion, and further can effectively improve the sealing effect of the sealing portion on the air inlet.

[0150] According to some embodiments of the present application, the material of the sealing portion 3211 is selected to be resistant to electrolyte, such as fluororubber, PFA, EPDM, etc. Different sealing materials have different physical properties, and the forces required to achieve sealing are also different accordingly.

[0151] Please refer to Fig.14 , Fig.14 Schematic diagram of the cross-sectional structure of the wall according to one or more embodiments. According to some embodiments of the present application, the one-way valve 30 is arranged on the wall, and the one-way valve 30 may be arranged on the end cover 21, and the end cover 21 is provided with a first exhaust hole 291, and the first exhaust hole 291 includes a through hole section 280 and a first hole section 281, and the through hole section 280 and the first hole section 281 are arranged along the thickness direction of the end cover 21, and the through hole section 280 connects the inside of the shell with the outside of the shell, and the first hole section 281 is located on the side of the through hole section 280 away from the inside of the shell, and the aperture of the first hole section 281 is larger than the aperture of the through hole section 280, and the one-way valve 30 is at least partially accommodated in the first hole section 281.

[0152] The first exhaust hole 291 is a countersunk hole recessed relative to the outer surface 21a of the end cover 21. When the one-way valve 30 is connected to the end cover 21, part of the structure of the one-way valve 30 can be embedded in the first exhaust hole 291 to reduce the installation height.

[0153] See also Fig.13According to some embodiments of the present application, a first step surface 311b and a second step surface 311c are provided on the side of the valve seat 311 facing the valve cover 312, the first step surface 311b is closer to the valve cover 312 than the second step surface 311c, and the first sink groove 3112 is provided on the first step surface 311b.

[0154] The first hole section 281 includes a hole side surface arranged circumferentially, and the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30 is welded to the hole side surface. The outer peripheral surface of the second step surface 311c is welded to the hole side surface.

[0155] According to some embodiments of the present application, the hole side surface matches the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30, and the hole side surface and the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30 are arranged at an acute angle to the central axis of the first exhaust hole 291. Through this arrangement, the connection strength can be enhanced.

[0156] According to some embodiments of the present application, the one-way valve 30 is welded to the end cover 21. Fig.13 As shown, the valve seat 311 of the one-way valve 30 can be connected to the end cover 21 by welding; specifically, the valve cover 312 of the one-way valve 30 is connected to the valve seat 311, and the valve seat 311 is welded to the end cover 21. In other embodiments, the valve seat 311 of the one-way valve 30 can also be connected to the valve cover 312, and the valve cover 312 is welded to the end cover 21.

[0157] According to some embodiments of the present application, a stress relief groove is provided around the third weld mark of the valve cover 312 / valve seat 311 and the end cover 21. The stress relief groove may be provided only on the end cover 21, or only on the valve cover 312 / valve seat 311, or on both the end cover 21 and the valve cover 312 / valve seat 311. Optionally, a first stress relief groove is provided on the surface of the valve seat 311 / valve cover 312 facing the outside of the shell; and / or a second stress relief groove is provided on the surface of the wall facing the outside of the shell.

[0158] According to some embodiments of the present application, the exhaust assembly includes a gas permeable membrane assembly 40 , wherein the gas permeable membrane assembly 40 includes a gas permeable membrane 41 , and the gas permeable membrane 41 is configured to allow gas inside the battery cell to pass through the gas permeable membrane and be discharged.

[0159] According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41, which is made of a breathable material and has good breathability, allowing gas molecules to pass through. By selecting the breathable membrane assembly 40 as the exhaust assembly, the battery cell can be in a closed state. The internal gas can be discharged through the breathable membrane 41, and the internal gas of the battery cell shell can be discharged outside the shell in time, so that the gas pressure inside the battery cell shell is not too high, reducing the risk of the pressure relief mechanism opening the valve in advance, and can greatly increase the life of the battery cell.

[0160] Furthermore, the breathable membrane 41 also has liquid isolation properties, blocking the passage of liquid, so it can block the overflow of electrolyte while discharging gas. In addition, the breathable membrane 41 can also block external water vapor, dust and impurities from entering the battery cell, protect the internal environment of the battery cell, and effectively improve the reliability of the battery cell. The breathable membrane 41 also has good weather resistance, chemical corrosion resistance, and structural stability. If it is an automotive power battery, it also needs to have oleophobicity. Therefore, the material of the breathable membrane 41 can be selected from polymer materials, such as polytetrafluoroethylene, polypropylene, polyethylene, polyurethane, etc. In addition, since the generation of gas inside the battery cell will cause the internal pressure to rise rapidly, the breathable membrane needs to have certain mechanical strength and elasticity.

[0161] Please refer to Fig.15 , Fig.15 Schematic diagram of the cross-sectional structure of a breathable membrane assembly according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41 and a connector 42, and the connector 42 is used to support the breathable membrane 41. The connector 42 is provided with a first breathable hole 491, the breathable membrane 41 is provided on the connector 42, the breathable membrane 41 covers the first breathable hole 491, and the breathable membrane is configured to allow the gas inside the battery cell to pass through the breathable membrane and be discharged.

[0162] The connector 42 can support the breathable membrane 41 and reduce the risk of excessive deformation of the breathable membrane 41. At the same time, the connector 42 can also serve as a medium for connecting other components of the breathable membrane assembly 40. The breathable membrane 41 is connected to other components through the connector 42 to improve the stability of the connection. The connector 42 is provided with at least one first air hole 491 as a release channel for the gas inside the battery cell so that the gas can pass through the connector 42. The shape of the first air hole 491 includes geometric shapes such as circle, square, and ellipse. The connector 42 can also be provided with multiple first air holes 491. The aperture, shape, and arrangement of the first air holes 491 are not specifically limited here. Optionally, the aperture of the first air hole 491 can be less than or equal to the aperture of the exhaust hole on the battery cell.

[0163] In one embodiment, the connector 42 may be a metal part, a resin part, etc. The material of the metal part may be copper, iron, aluminum, steel, or aluminum alloy, etc. By selecting the connector 42 as a metal part, it is convenient to weld the connector 42 to the wall. The following will take the connector 42 as a metal part to illustrate the present application scheme, but it should not be limited to this, and should not bring limitations to the present application scheme, and it is still applicable to connectors made of non-metal materials.

[0164] like Fig.15 As shown in (a), the air permeable membrane 41 can be directly disposed on the surface of the metal member 42. In other embodiments, a sink can also be disposed on the metal member 42.

[0165] See also Fig.15 As shown in (b), according to some embodiments of the present application, the metal member 42 has a first annular table surface T1 that is recessed relative to the surface of the metal member 42, the first annular table surface T1 is arranged around the first vent hole 491, and the vent membrane 41 is arranged on the first annular table surface T1. Through this arrangement, the installation height of the vent membrane assembly 40 can be reduced.

[0166] See also Fig.16 , Fig.16 Schematic diagram of the cross-sectional structure of the breathable membrane assembly 40 according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 further includes a backing member 43, which is disposed between the breathable membrane 41 and the metal member 42, and the air permeability of the backing member 43 is greater than the air permeability of the breathable membrane 41.

[0167] The breathable membrane assembly 40 includes a breathable membrane 41, a metal member 42 and a backing member 43. The breathable membrane 41 is disposed on the metal member 42. The backing member 43 is disposed between the breathable membrane 41 and the metal member 42. The backing member 43 is used to support the breathable membrane 41 and allow gas to pass through the breathable membrane 41.

[0168] The backing member 43 can support the breathable membrane 41 and reduce the risk of deformation of the breathable membrane 41. The backing member 43 is made of a material with better air permeability than the breathable membrane 41 so as not to affect the air permeability of the breathable membrane 41; the backing member 43 also has the characteristics of corrosion resistance and high temperature resistance. The material selection of the backing member 43 is rich, including porous polymers such as polypropylene, polyamide, polytetrafluoroethylene, polyperfluoroethylene propylene, etc., and can also be metal organic framework porous materials, as well as carbon membrane and ceramic porous materials, etc., which are not limited here.

[0169] like Fig.16As shown in (a), the metal part 42 also has a second annular table T2 that is recessed relative to the surface of the metal part 42. The second annular table T2 is arranged around the first air hole 491, and the backing member 43 is arranged on the second annular table T2. The second annular table T2 carries the backing member 43, and the breathable membrane 41 can be directly attached to the surface of the metal part 42. In this way, because the thickness of the breathable membrane 41 is relatively small, the overall height of the breathable membrane assembly 40 is relatively small. By reducing the setting of the recessed surface on the metal part 42, on the one hand, the manufacturing process can be simplified, and on the other hand, the strength of the metal part 42 can be improved.

[0170] like Fig.16 As shown in (b), the metal part 42 has a first annular table T1 and a second annular table T2 which are recessed relative to the surface of the metal part 42, and a transition surface T3. The first annular table T1 is arranged around the second annular table T2, and the transition surface T3 connects the first annular table T1 and the second annular table T2. The first annular table T1 is closer to the surface of the metal part 42 than the second annular table T2. The second annular table T2 is arranged around the first air hole 491. The backing member 43 is arranged on the second annular table T2, and the air permeable membrane 41 is arranged on the first annular table T1.

[0171] The first annular table surface T1 and the second annular table surface T2 are formed by the surface of the metal member 42 being recessed inwardly, and the first annular table surface T1 and the second annular table surface T2 may be formed by stamping the metal member 42, or the first annular table surface T1 and the second annular table surface T2 may be formed by etching the metal member 42 and removing part of the structure. The recess depth of the first annular table surface T1 and the second annular table surface T2 relative to the surface of the metal member 42 may be set according to the thickness of the breathable membrane 41 and the backing member 43. Preferably, the recess depth of the second annular table surface T2 relative to the first annular table surface T1 (i.e., the height of the transition surface T3) is equal to the thickness of the backing member 43, so that the second annular table can accommodate the backing member 43, and the surface of the backing member 43 facing the breathable membrane 41 is flush with the first annular table surface T1. Furthermore, the depression depth of the first annular platform T1 relative to the surface of the metal member 42 is equal to the thickness of the breathable membrane 41 , so that the first annular platform can accommodate the breathable membrane 41 , and the side surface of the breathable membrane 41 away from the metal member 42 is flush with the surface of the metal member 42 .

[0172] By providing a recessed sink on the metal member 42 , the surface of the breathable membrane 41 can be flush with the surface of the metal member 42 , thereby reducing the overall height of the breathable membrane assembly 40 and further reducing the installation height of the breathable membrane assembly 40 .

[0173] In one embodiment, the breathable membrane 41 and the metal part 42 are compositely connected, for example, the breathable membrane 41 and the metal part 42 can be connected by using a nano injection molding process. Nano injection molding refers to nano molding technology (NMT, i.e., Nano Molding Technology), which is a process of combining metal and plastic using nano technology. That is, the metal surface is first nano-treated, and then the plastic is directly injection-molded on the metal surface, so that the metal and plastic can be integrally formed and finally combined into a product. The "nano" referred to here refers to a microporation process, that is, the metal surface is subjected to nano-scale microporation treatment through a specific solution, and the main purpose is to make the metal surface and the plastic better combined and improve the connection strength.

[0174] According to some embodiments of the present application, the breathable membrane assembly 40 is disposed on the wall portion, the wall portion has a first sinking platform S1 that is recessed relative to the surface of the wall portion, the first sinking platform S1 is disposed around the second exhaust hole 292, and the breathable membrane assembly 40 is at least partially located on the first sinking platform S1. The breathable membrane assembly 40 may be disposed on the end cover 21.

[0175] Please refer to Fig.17 and Fig.18 , Fig.17 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. Fig.18 Schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the end cap 21 has a first sinking platform S1 that is recessed relative to the surface of the end cap 21, the first sinking platform S1 is arranged around the second exhaust hole 292, and at least a portion of the breathable membrane assembly 40 is arranged on the first sinking platform S1.

[0176] The end cap 21 includes an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a is disposed toward the outside of the shell, and the inner surface 21b is disposed toward the inside of the shell. The breathable membrane assembly 40 can be disposed on the side of the end cap 21 facing the inside of the shell, or on the side of the end cap 21 facing the outside of the shell.

[0177] like Fig.17 As shown in (a) and (b), the breathable membrane assembly 40 is arranged on the side of the end cap 21 facing the inside of the shell. The end cap 21 has an outer surface 21a and an inner surface 21b arranged opposite to each other, the outer surface 21a is arranged toward the outside of the shell, and the inner surface 21b is arranged toward the inside of the shell, and the end cap 21 has a first sink S1 that is recessed relative to the inner surface 21b of the end cap 21.

[0178] Specifically, the first sinking platform S1 is recessed relative to the inner surface 21 b of the end cover 21 , and the breathable membrane assembly 40 is disposed on the first sinking platform S1 . Optionally, the breathable membrane assembly 40 may be connected to the end cover 21 via a metal member 42 .

[0179] Among them, the first depression S1 is formed by the inner surface 21b of the end cover 21 being recessed in the direction of the outer surface 21a of the end cover 21. The end cover 21 may be stamped to form the recessed first depression S1, or the end cover 21 may be etched to remove part of the structure to form the recessed first depression S1. The recess depth of the first depression S1 relative to the inner surface 21b of the end cover 21 can be set according to the thickness of the breathable membrane assembly 40. The thickness of the breathable membrane assembly 40 is the overall thickness including the breathable membrane 41, the metal part 42 and the backing part 43. As mentioned above, the breathable membrane 41 and the backing part 43 can be accommodated in the annular platform on the metal part 42 that is recessed relative to the surface of the metal part 42, that is, the overall thickness of the breathable membrane assembly 40 can be equal to the thickness of the metal part 42. Preferably, the depression depth of the first depression S1 relative to the inner surface 21b of the end cover 21 is equal to the thickness of the breathable membrane assembly 40, so that the breathable membrane assembly 40 is accommodated in the first depression S1, and the surface of the breathable membrane assembly 40 facing the inside of the shell is flush with the inner surface 21b of the end cover 21. In this way, the installation height of the breathable membrane assembly 40 can be reduced, thereby reducing the occupation of the internal space of the battery cell 20 shell and improving the space utilization rate inside the shell.

[0180] like Fig.17 As shown in (a), the air permeable membrane 41 may be arranged on the side of the metal member 42 facing the inside of the housing; this arrangement can reduce the influence of the working environment of the battery cell 20 on the air permeable membrane 41. Fig.17 As shown in (b), the breathable membrane 41 may also be arranged on the side of the metal member 42 facing the end cover 21, that is, the breathable membrane 41 is arranged between the metal member 42 and the end cover 21; this arrangement can facilitate the assembly of the breathable membrane assembly 40.

[0181] like Fig.18 As shown, the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the outside of the housing. Specifically, the first sinking platform S1 is recessed relative to the outer surface 21a of the end cover 21, and the breathable membrane assembly 40 is arranged on the first sinking platform S1 and connected to the end cover 21 through the metal member 42. In this embodiment, the first sinking platform S1 is formed by the outer surface 21a of the end cover 21 being recessed toward the inner surface 21b of the end cover 21. Similarly, the recessed depth of the first sinking platform S1 relative to the outer surface 21a of the end cover 21 can be equal to the thickness of the breathable membrane assembly 40.

[0182] like Fig.18 As shown, the breathable membrane 41 is arranged on the side of the metal part 42 facing the inside of the housing, that is, the breathable membrane 41 is arranged between the end cover 21 and the metal part 42. Through this arrangement, the breathable membrane 41 can be less affected by the working environment of the battery cell 20. In other embodiments, the breathable membrane 41 can also be arranged on the side of the metal part 42 facing the outside of the housing.

[0183] According to some embodiments of the present application, the connecting member is connected to the wall portion by welding; optionally, a stress relief groove is provided around a fourth weld mark between the connecting member and the wall portion; optionally, a third stress relief groove is provided on the connecting member around the fourth weld mark between the connecting member and the wall portion; and / or a second stress relief groove is provided on the wall portion around the fourth weld mark between the connecting member and the wall portion.

[0184] Please refer to Fig.19 , Fig.19 Schematic diagram of the exploded structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes a protective patch 60, which is disposed on the side of the end cap 21 facing the outside of the housing. That is, the protective patch 60 is disposed on the outer surface 21a of the end cap 21 to provide a certain degree of protection for the end cap 21. The material of the protective patch 60 can be a variety of materials, such as rubber, silicone or plastic.

[0185] According to some embodiments of the present application, the protective patch 60 is provided with a first avoidance hole 601 penetrating the protective patch 60 , and the first avoidance hole 601 is used for the one-way valve 30 in the exhaust assembly to pass through.

[0186] According to some embodiments of the present application, in an embodiment where an electrode terminal 25 is provided on the end cap 21, see Fig.19 As shown, the protective patch 60 is provided with a second avoidance hole 602 at the position corresponding to the electrode terminal 25, and the second avoidance hole 602 runs through both sides of the protective patch 60. The second avoidance hole 602 is used to allow the electrode terminal 25 to pass through to avoid the electrode terminal 25. Exemplarily, two electrode terminals 25 are provided on the end cover 21, and correspondingly, the protective patch 60 is provided with two second avoidance holes 602, each of which is used for one electrode terminal 25 to pass through.

[0187] According to some embodiments of the present application, the protective patch 60 is provided with an information collection hole 603 that penetrates the protective patch 60 , and the information collection hole 603 serves to expose part of the end cover 21 , so as to facilitate setting an information code on the end cover 21 or connecting a detection element for sampling, etc.

[0188] In some embodiments, the permeability rate of the breathable membrane 41 is 3-10 mL / day. It can be 3-4 mL / day, 5-8 mL / day, 9-10 mL / day. By setting the exhaust rate of the breathable membrane 41 to 3-10 mL / day, the phenomenon that the pressure relief mechanism 70 cannot be actuated and opened due to excessive exhaust can be alleviated when the battery cell 20 has thermal runaway, so that the pressure relief mechanism 70 can be actuated and stably discharge the internal pressure of the battery cell 20 when the battery cell 20 has thermal runaway, thereby helping to reduce the risk of fire and explosion of the battery cell 20 when the battery cell 20 has thermal runaway. At the same time, the airtightness of the system is also considered to prevent the exhaust rate from being too fast, resulting in poor airtightness, so as to maintain the airtightness of the battery system while exhausting the gas.

[0189] The test method for the exhaust rate of the breathable membrane 41 may be tested in accordance with GB / T1038-2000.

[0190] According to some embodiments of the present application, the opening pressure of the one-way valve is greater than or equal to 0.2MPa; optionally, greater than or equal to 0.4MPa; and optionally, greater than or equal to 0.8MPa. Exemplarily, the opening pressure of the valve core can be 0.20MPa, 0.25MPa, 0.30MPa, 0.35MPa, 0.40MPa, 0.45MPa, 0.50MPa, 0.55MPa, 0.60MPa, 0.65MPa, 0.70MPa, 0.75MPa, 0.80MPa, 0.90MPa, 1.00MPa.

[0191] The one-way valve opening pressure test method and principle can be tested based on the helium leakage standard, which is defined as follows: if the leakage rate is less than 10^-6Pa.m^3 / s, the system is considered to be sealed; if the leakage rate is greater than 10^-6Pa.m^3 / s, it indicates that there is gas leakage in the system.

[0192] During the test, the test chamber is sealed with a one-way valve, and helium is filled into the test chamber. The amount of helium in the environment of the test chamber is monitored with a helium detector. If helium is detected and the leakage rate is greater than 10^-6Pa.m^3 / s, it means that the test chamber is no longer sealed and helium is leaking out. The helium leakage rate is continuously monitored. When the leakage rate is greater than 10^-5Pa.m^3 / s, the one-way valve is determined to be open for deflation, and the pressure of the test chamber at this time is recorded as the opening pressure of the one-way valve.

[0193] In some embodiments, the battery cell 20 is an alkali metal battery, such as a sodium metal battery, a lithium metal battery, a magnesium metal battery, etc. The alkali metal battery is used in conjunction with the exhaust assembly to timely exhaust the gas generated by the alkali metal battery during normal operation, thereby increasing the service life of the alkali metal battery.

[0194] Among them, the electrode assembly 23 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute the tabs. The positive tab and the negative tab can be located at one end of the main body or at both ends of the main body respectively. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0195] In one embodiment, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer disposed on at least one side of the positive electrode current collector, and the positive electrode active layer includes a positive electrode active material.

[0196] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode active layer may be disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0197] In one embodiment, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0198] In one embodiment, the positive electrode material includes one or more of a polyanion positive electrode material, a phosphate positive electrode material, a sulfate positive electrode material, a silicate positive electrode material, and a borate positive electrode material. For example, in the positive electrode active material of a sodium battery, the polyanion compound includes a compound based on phosphoric acid and fluorophosphoric acid. The phosphoric acid-based compound includes Na x1 Fe y1 P m1 O n1 For example, sodium iron phosphate with a higher capacity and sodium iron pyrophosphate with a higher voltage platform. Polyanionic compounds include sodium vanadium trifluorophosphate Na3V2(PO4)2F3, sodium vanadium fluorophosphate NaVPO4F, sodium vanadium phosphate Na3V2(PO4)3, Na4Fe3(PO4)2P2O7, NaFePO4, Na3V2(PO4)3. Prussian blue compounds are Na xMM(CN)6, wherein M and M are one or more of Fe, Mn, Co, Ni, Cu, Zn, Cr, Ti, V, Zr, and Ce, and wherein 0<x≤2. The positive electrode active material in the lithium metal battery may include at least one of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, or lithium manganese iron phosphate.

[0199] In one embodiment, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active layer includes a negative electrode active material. In this embodiment, the battery cell is an ion battery. During the charge and discharge process of the battery, active ions (such as Li + 、Na + ) is embedded / deintercalated in the negative electrode active material.

[0200] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode active layer may be disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0201] In one embodiment, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, a copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be obtained by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0202] In one embodiment, the negative electrode active material may include one or more of a silicon-based material, a silicon-carbon material, a carbon material, and a selenium-based material. Specifically, it includes one or more of artificial graphite, natural graphite, hard carbon, soft carbon, a silicon-based material, and a selenium-based material. The silicon-based material may be selected from one or more of elemental silicon, silicon oxide compounds (such as silicon monoxide), silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The selenium-based material may be selected from one or more of elemental selenium, selenium oxide compounds, and selenium alloys.

[0203] In one embodiment, the negative electrode plate includes a negative electrode current collector and a carbonaceous coating disposed on at least one surface of the negative electrode current collector. In this embodiment, the battery cell is a metal battery, and during the battery charging and discharging process, active ions are deposited / stripped at the negative electrode plate. The metal battery can be an alkali metal battery, such as a lithium metal battery, a sodium metal battery, a potassium metal battery, a zinc metal battery, or an aluminum metal battery. This type of battery can also be called a "negative electrode-free battery". During the charging process, active ions (such as Na +) is deposited on the negative electrode current collector to form sodium metal. The provision of the carbon-containing coating is conducive to making the metal deposition more uniform. The carbon-containing material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

[0204] In other embodiments, a conductive film layer may also be deposited on the negative electrode current collector. For example, alloy materials, titanium-based materials, active metals (such as sodium metal), carbon-based materials deposited with metals, composite materials containing metals, alloy materials containing metals, etc. The above alloy materials include but are not limited to sodium-tin alloys, sodium-germanium alloys, and sodium-antimony alloys. The above titanium-based materials include but are not limited to titanium dioxide, titanates, and titanium phosphates.

[0205] In one embodiment, the positive electrode active layer and the negative electrode active layer may also include a binder and a conductive agent. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0206] In one embodiment, the isolation membrane can be any known porous structure isolation membrane with good chemical stability and mechanical stability.

[0207] In one embodiment, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0208] The electrolyte conducts ions between the positive electrode and the negative electrode. The electrolyte can be liquid, gel or all-solid.

[0209] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent. The electrolyte salt dissolves to form electrolyte ions, and conduction is achieved through the movement of the electrolyte ions in the electrolyte salt.

[0210] In one embodiment, in the sodium battery, the electrolyte salt includes sodium hexafluorophosphate (NaPF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium trifluoromethanesulfonate (CF3NaO3S), sodium sulfide (Na2S) and other sodium salts. The lithium battery includes at least one lithium salt selected from lithium perchlorate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalatoborate, lithium tetrafluoroborate and lithium trifluoromethanesulfonate.

[0211] In one embodiment, the solvent includes one or more solvents selected from chain ethers, ethylene glycol dimethyl ether and its derivatives, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and cyclic ethers, including dimethyl ether (DME), diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, 2,2,2,2-trifluoroethyl ether, ethylene glycol diethyl ether, triethylene glycol dimethyl ether, ethylene glycol dimethyl ether derivatives, methyl trifluoroethyl carbonate (FEMC), dioxolane (DOL), acetonitrile (AN), fluorobenzene, triethyl phosphate (TEP), sulfolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylacetamide, etc.

[0212] In one embodiment, the electrolyte may further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0213] According to some embodiments of the present application, the present application further provides a battery 100, the battery 100 comprising a battery cell 20 of any of the above solutions. Fig. 20 , Fig. 20 1 is a schematic diagram of the exploded structure of a battery according to one or more embodiments. The battery 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is accommodated in the box body 10. Among them, the box body 10 is used to provide a storage space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, and the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space for accommodating the battery cell 20. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0214] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0215] Each battery cell 20 may be a secondary battery or a primary battery; specific examples thereof include all types of primary batteries or secondary batteries. For example, it may be a lithium battery, a sodium battery, a potassium battery, or other types of secondary batteries. A lithium secondary battery may include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery. It may also be a lithium sulfur battery, a sodium ion battery, or a magnesium ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0216] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0217] According to some embodiments of the present application, the present application further provides an electric device, which includes a battery cell according to any of the above solutions, and the battery cell is used to provide electric energy for the electric device. The electric device can be any of the above devices or systems using the battery cell.

[0218] In some embodiments, the purpose of the electric equipment of the present application is not particularly limited, and it can be used for any electronic device known in the prior art. The battery disclosed in the embodiment of the present application can be used for electric equipment using the battery as a power source or various energy storage systems using the battery as an energy storage element. That is, a kind of electric equipment is provided, in some embodiments, the electric equipment of the present application can be used for, but not limited to, notebook computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini-discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household batteries and lithium-ion capacitors, etc.

[0219] Electrical equipment can choose battery cells, battery modules or battery packs according to its usage requirements.

[0220] Please refer to Fig.21 , Fig.21 : is a schematic diagram of the structure of a vehicle according to one or more embodiments. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, the head or the tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0221] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0222] In the above embodiments, by providing a breathable membrane assembly, the battery cell can discharge internal gas through the breathable membrane in a sealed state, and the internal gas of the battery shell can be discharged to the outside of the shell in time, so that the air pressure inside the battery shell will not be too high, reducing the risk of the pressure relief mechanism opening the valve prematurely, which can greatly improve the life of the battery cell. One or more breathable membrane assemblies can be provided on a battery cell, and the location and manner of the provision of each breathable membrane assembly can be different, for example, one breathable membrane assembly is provided on the side of the end cover facing the inside of the battery shell, and one breathable membrane assembly is provided on the side of the end cover facing the outside of the battery shell. One breathable membrane assembly can be provided on the end cover, and the other breathable membrane assembly can be provided on the shell.

[0223] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: a housing having a wall portion; An exhaust assembly, disposed on the wall portion, the exhaust assembly comprising a one-way valve and / or a breathable membrane assembly, the breathable membrane assembly comprising a breathable membrane, and the exhaust assembly is used to exhaust the gas inside the housing; The wall portion is provided with a first weak strength area, and the first weak strength area is arranged along the circumference of the exhaust component.

2. The battery cell according to claim 1, characterized in that: The first strength weakened area includes a first thickness weakened area.

3. The battery cell according to claim 1 or 2, characterized in that: The first weak strength area includes a first groove recessed relative to the surface of the wall portion, and the first groove is arranged around the exhaust component.

4. The battery cell according to claim 3, characterized in that: The wall portion has an outer surface and an inner surface that are arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; The first groove is recessed relative to the outer surface; and / or The first groove is recessed relative to the inner surface.

5. The battery cell according to claim 1 or 2, characterized in that: The first weak strength area includes a plurality of second grooves recessed relative to the surface of the wall portion, and the plurality of second grooves are arranged at intervals in the circumferential direction of the exhaust component.

6. The battery cell according to claim 3, 4 or 5, characterized in that: The first weak strength area further includes a notch arranged at the bottom of the first groove and / or the second groove.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The wall portion includes a wall body and a sinking portion, the wall body has an outer surface and an inner surface arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; the sinking portion is connected to the wall body, the sinking portion protrudes from the inner surface, and the first strength weak area is arranged on the sinking portion.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The wall portion is provided with a first exhaust hole, the first exhaust hole communicates the inside of the shell with the outside of the shell, and the exhaust component includes a one-way valve, and the one-way valve covers the first exhaust hole.

9. The battery cell according to claim 8, characterized in that: The wall portion has an outer surface and an inner surface arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; the one-way valve is arranged on the outer surface, and the one-way valve includes a valve body, at least part of which protrudes from the outer surface.

10. The battery cell according to claim 9, characterized in that: The valve body is provided with a second weak strength area, the actuation pressure of the second weak strength area is greater than the valve opening pressure of the one-way valve, and the actuation pressure of the second weak strength area is less than the actuation pressure of the first weak strength area.

11. The battery cell according to claim 10, characterized in that: The valve body has a valve cavity inside, the valve body includes a valve seat and a valve cover, the valve cover includes a cover top wall and a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the valve seat enclose the valve cavity, and the second strength weak area is arranged on the cover side wall.

12. The battery cell according to claim 11, characterized in that: The second weak strength area includes a plurality of third grooves arranged on the side wall of the cover.

13. The battery cell according to claim 8, characterized in that: The one-way valve includes a valve body and a valve core, the valve body has a valve cavity inside, the valve body is provided with an air inlet and an air outlet, the air inlet is used to connect the valve cavity with the inside of the shell, and the air outlet is used to connect the valve cavity with the outside of the shell; the valve core is arranged in the valve cavity, the valve core is used to block the air inlet, and the valve core is configured to open the air inlet under the action of the gas inside the shell and release the gas inside the battery cell.

14. The battery cell according to claim 13, characterized in that: The valve body comprises: Valve seat; The valve cover comprises a cover top wall and a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the valve seat enclose the valve cavity, the valve seat is provided with the air inlet, the valve cover is provided with the air outlet, the valve seat has a first through hole penetrating the valve seat, and the air inlet is the first through hole.

15. The battery cell according to claim 14, characterized in that: The cover side wall has a second through hole penetrating the cover side wall, and the air outlet is the second through hole.

16. The battery cell according to claim 15, characterized in that: The second through hole extends to an end of the cover side wall in a direction away from the cover top wall.

17. The battery cell according to claim 16, characterized in that: There are a plurality of the second through holes, and the plurality of the second through holes are distributed at intervals in the circumferential direction of the cover side wall.

18. The battery cell according to any one of claims 14 to 17, characterized in that: The valve cover also includes a flange wall, the cover side wall connects the cover top wall and the flange wall, the flange wall extends toward a side away from the valve cavity relative to the cover side wall, and the flange wall is connected to the valve seat.

19. The battery cell according to claim 18, characterized in that: A first recessed groove that is recessed relative to the surface of the valve seat is disposed on a side of the valve seat that faces the valve cover, and at least a portion of the flange wall is accommodated in the first recessed groove and connected to the valve seat.

20. The battery cell according to claim 18 or 19, characterized in that: The flange wall is welded to the valve seat; wherein, in the circumferential direction of the cover side wall, at least a portion of a first weld mark between the flange wall and the valve seat is staggered with a second through hole on the cover side wall.

21. The battery cell according to any one of claims 14 to 20, characterized in that: The valve core comprises: An elastic member, disposed in the valve cavity; A blocking member is movably disposed in the valve cavity, and is used to block the air inlet under the action of the elastic member, and is used to open the air inlet under the action of the gas inside the shell.

22. The battery cell according to claim 21, characterized in that: The sealing member includes a pressing portion and a sealing portion. Along the axial direction of the valve cavity, the two ends of the elastic member respectively abut against the valve cover and the pressing portion. The sealing portion is connected to a side of the pressing portion away from the valve cover, and the sealing portion is used to seal the air inlet.

23. The battery cell according to any one of claims 14 to 22, characterized in that: The first exhaust hole includes a through hole segment and a first hole segment, the through hole segment and the first hole segment are arranged along the thickness direction of the wall portion, the first hole segment is located on the side of the through hole segment away from the interior of the shell, the aperture of the first hole segment is larger than the aperture of the through hole segment, and the one-way valve is at least partially accommodated in the first hole segment.

24. The battery cell according to claim 23, characterized in that: The first hole section includes a circumferentially arranged hole side surface, and the valve seat is provided with a first step surface and a second step surface on the side facing the valve cover. The first step surface is closer to the valve cover than the second step surface, and the outer circumferential surface of the second step is welded to the hole side surface.

25. The battery cell according to any one of claims 1 to 7, characterized in that: The wall portion includes a pressure relief mechanism and a pressure relief hole, the pressure relief hole connects the inside of the shell and the outside of the shell, the pressure relief mechanism includes a pressure relief sheet, the pressure relief sheet covers the pressure relief hole, the first strength weak area is arranged on the pressure relief sheet, the pressure relief mechanism is configured to actuate and release the internal pressure of the battery cell when the battery cell thermally runs away, and the actuation pressure of the pressure relief mechanism is greater than the actuation pressure of the first strength weak area.

26. The battery cell according to claim 25, characterized in that: A second exhaust hole is provided on the pressure relief sheet, and the second exhaust hole connects the interior of the shell with the exhaust assembly. The exhaust assembly includes a one-way valve or a breathable membrane assembly, and the one-way valve or the breathable membrane assembly is provided on the pressure relief sheet and covers the second exhaust hole.

27. The battery cell according to any one of claims 1 to 24, characterized in that: The wall portion is provided with a first exhaust hole, the first exhaust hole communicates the inside of the shell with the outside of the shell, and the exhaust assembly includes a breathable membrane assembly, and the breathable membrane assembly covers the first exhaust hole.

28. The battery cell according to claim 27, characterized in that: The breathable membrane assembly includes a breathable membrane and a connector, the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged, the connector is provided with a first breathable hole, and the breathable membrane is provided on the connector and covers the first breathable hole.

29. The battery cell according to claim 28, characterized in that: The connecting member has a first annular table surface which is recessed relative to the surface of the connecting member. The first annular table surface is arranged around the first air permeable hole, and the air permeable membrane is arranged on the first annular table surface.

30. The battery cell according to claim 28 or 29, characterized in that: The breathable membrane assembly further comprises a backing member, which is arranged between the breathable membrane and the connecting member, and the air permeability rate of the backing member is greater than the air permeability rate of the breathable membrane.

31. The battery cell according to claim 30, characterized in that: The connecting member has a second annular table surface which is recessed relative to the surface of the connecting member. The second annular table surface is arranged around the first air vent, and the backing member is arranged on the second annular table surface.

32. The battery cell according to any one of claims 28 to 31, characterized in that: The connecting piece is a metal piece.

33. The battery cell according to any one of claims 28 to 32, characterized in that: The breathable membrane is arranged on a side of the connecting member facing the inside of the shell, and the breathable membrane covers the first breathable hole.

34. The battery cell according to any one of claims 27 to 33, characterized in that: The wall portion has a first sunken platform that is recessed relative to the surface of the wall portion. The first sunken platform is arranged around the first exhaust hole, and the breathable membrane assembly is at least partially located on the first sunken platform.

35. The battery cell according to any one of claims 1 to 34, characterized in that: The housing comprises: A housing having an opening formed therein, wherein the housing is used to accommodate the electrode assembly; an end cap for closing the opening; Wherein, the end cover is the wall portion; or The housing includes the wall portion; or The wall portion is a wall located at the top of the housing when the battery cell is in a placed state.

36. A battery, characterized in that: Comprising a battery cell as described in any one of claims 1-35.

37. An electrical equipment, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 35, wherein the battery cell is used to provide electrical energy.

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