WO2025119017A1 - Battery cell, battery and electrical device - Google Patents

Abstract

Disclosed in the present application are a battery cell, a battery and an electrical device. The battery cell comprises a casing and an exhaust component, the casing being provided with a wall part and an accommodation chamber, the exhaust component being arranged on the wall part, and the exhaust component being used for discharging gas in the casing. The battery cell further comprises an electrolyte, and the electrolyte is filled in the accommodation chamber. The conductivity of the electrolyte is 2 ms/cm≤conductivity≤16 ms/cm, and the exhaust rate of the exhaust component is 0.6 mL/day≤exhaust rate≤10.0 mL/day. By matching battery cells having electrolytes of different conductivities with exhaust components of different exhaust rates, the solution of the present application can balance the contradiction between high conductivity requirements and high gas production amounts, and reduces the impact of external water vapor intrusion on batteries in the exhaust process.

Description

Battery cells, batteries and electrical equipment Technical Field

This application claims priority to Chinese patent application 202323354804.5, filed on December 8, 2023, entitled “Battery Cell, Battery and Electrical Equipment”, the entire contents of which are incorporated herein by reference.

Technical Field

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

As global energy and environmental issues continue to intensify, new energy is developing rapidly as one of the areas of sustainable development. Batteries are increasingly used as a new energy source, and there are high requirements for their safety and service life. During the charging and discharging process of the battery, the generation of gas inside the battery will cause the internal pressure of the battery to increase, reduce the safety of the battery cells, and shorten the service life of the battery cells. 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

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 internal gas of the battery cell to the outside of the outer casing in time, so that the gas pressure inside the battery cell is maintained at a normal level, which can improve the safety performance of the battery and greatly increase the battery life.

In order to solve the above problems, a technical solution adopted by the present application is: to provide a battery cell, the battery cell includes a shell and an exhaust assembly, the shell has a wall portion and a receiving cavity, the exhaust assembly is arranged on the wall portion, and the exhaust assembly is used to exhaust the gas inside the shell. The exhaust assembly can timely exhaust the gas inside the battery cell to the outside of the shell, so that the gas pressure inside the battery cell is maintained at a normal level, which can improve the safety performance of the battery and greatly increase the battery life.

Furthermore, the battery cell also includes an electrolyte, and the electrolyte is filled in the containing cavity. Among them, the conductivity of the electrolyte is: 2ms/cm≤conductivity≤16ms/cm, and the exhaust rate of the exhaust component is: 0.6mL/day≤exhaust rate≤10.0mL/day. Battery cells with electrolytes of different conductivities are equipped with exhaust components with different exhaust rates, which can balance the contradiction between high conductivity requirements and high gas production, while reducing the impact of external water vapor intrusion on the battery during the exhaust process.

In one embodiment, the conductivity of the electrolyte is: 8ms/cm≤conductivity≤16ms/cm; the exhaust rate of the exhaust component is: 3.3mL/day≤exhaust rate≤10.0mL/day. The electrolyte has a higher conductivity and the gas production of the battery cell is larger. The exhaust component with a larger exhaust rate can exhaust the gas in time.

In one embodiment, the conductivity of the electrolyte is: 11ms/cm≤conductivity≤14ms/cm, and the exhaust rate of the exhaust assembly is 4.5mL/day≤exhaust rate≤9.0mL/day. This can make the exhaust rate and the electrolyte conductivity match more accurately, while improving the charging capacity and energy density of the battery cell, taking into account the safety performance and service life of the battery cell.

In one embodiment, the conductivity of the electrolyte is: 2ms/cm≤conductivity≤8ms/cm; the exhaust rate of the exhaust assembly is: 0.6mL/day≤exhaust rate≤5.0mL/day. The conductivity of the electrolyte is relatively low, and the gas production of the battery cell is relatively low. The exhaust assembly with a relatively low exhaust rate can timely exhaust the gas inside the battery and reduce the probability of external impurities (air, moisture, dust, etc.) entering the battery cell.

In one embodiment, the conductivity of the electrolyte is: 4ms/cm≤conductivity≤6ms/cm; the exhaust rate of the exhaust assembly is 1.3mL/day≤second exhaust rate≤3.9mL/day; the exhaust rate and electrolyte conductivity can be matched more accurately, taking into account the safety performance and service life of the battery cell.

In one embodiment, the exhaust assembly includes a breathable membrane assembly, the breathable membrane assembly includes a breathable membrane, and the breathable membrane has a permeability rate of 3-10 mL/day, which can timely discharge the gas inside the battery cell and prevent external impurities (air, moisture, dust, etc.) from entering the battery cell.

In one embodiment, the air permeable membrane includes a first air permeable membrane, and the air permeability of the first air permeable membrane is 3-4 mL/day, which can match the battery cell corresponding to the electrolyte with relatively low conductivity.

In one embodiment, the air permeable membrane includes a second air permeable membrane, and the air permeability of the second air permeable membrane is 9-10 mL/day, which can match the battery monomer corresponding to the electrolyte with relatively large conductivity.

In one embodiment, the exhaust assembly includes a one-way valve, and 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. By adjusting the valve opening pressure, different application scenarios and different exhaust requirements can be adapted.

In one embodiment, the exhaust assembly includes a breathable membrane assembly and a one-way valve, the wall portion has a first exhaust hole, the first exhaust hole communicates with the inside of the shell and the outside of the shell, and the battery cell is configured so that the gas exhausted through the first exhaust hole flows through the one-way valve and the breathable membrane assembly. At this time, the breathable membrane assembly and the one-way valve are arranged in series, and the one-way valve can protect the sealing of the battery cell system and reduce the probability of external water vapor entering the battery cell system; at the same time, the breathable membrane can prevent the overflow of the electrolyte and realize the closure of the battery system when the one-way valve is open.

In one embodiment, the opening pressure of the one-way valve is greater than or equal to 0.4 MPa, the breathable membrane assembly includes a second breathable membrane, and the second breathable membrane has a permeability rate of 9-10 mL/day. When arranged in series, with a breathable membrane with a larger permeability rate, the one-way valve can be vented faster when it is opened.

In one embodiment, the exhaust assembly includes a breathable membrane assembly and a one-way valve, the wall portion has a first exhaust hole and a third exhaust hole arranged at intervals, the first exhaust hole and the third exhaust hole are connected to the inside of the shell and the outside of the shell respectively, and the battery cell is configured so that the gas exhausted through the first exhaust hole flows through the one-way valve, and the gas exhausted through the third exhaust hole flows through the breathable membrane assembly. In this case, the breathable membrane assembly and the one-way valve are arranged in parallel, and the two can exhaust gas at the same time to achieve a relatively large exhaust rate.

In one embodiment, the opening pressure of the one-way valve is greater than or equal to 0.8 MPa, the breathable membrane assembly includes a first breathable membrane, and the air permeability rate of the first breathable membrane is 3-4 mL/day. When arranged in parallel, with a breathable membrane with a lower air permeability rate, the risk of external water vapor entering the battery cell through the breathable membrane when the breathable membrane has a higher air permeability can be reduced.

In one embodiment, the gas production rate of the battery cell is: 0.006 mL/Ah/D≤gas production rate≤0.066 mL/Ah/D. A suitable exhaust component can be matched according to the gas production rate of the battery.

Optionally, the gas production rate of the battery cell is: 0.006 mL/Ah/D≤gas production rate≤0.033 mL/Ah/D. A suitable exhaust component can be matched according to the gas production rate of the battery.

Furthermore, the gas production rate of the battery cell is: 0.013mL/Ah/D≤gas production rate≤0.026mL/Ah/D. A suitable exhaust component can be matched according to the gas production rate of the battery.

Optionally, the gas production rate of the battery cell is: 0.033 mL/Ah/D≤gas production rate≤0.066 mL/Ah/D. A suitable exhaust component can be matched according to the gas production rate of the battery.

Furthermore, the gas production rate of the battery cell is: 0.045 mL/Ah/D≤gas production rate≤0.060 mL/Ah/D. A suitable exhaust component can be matched according to the gas production rate of the battery.

In one embodiment, the electrolyte includes one or more of chain ethers, ethylene glycol dimethyl ether and its derivatives, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and cyclic ethers, which can reduce the risk of gas generation caused by the electrolyte.

In one embodiment, the battery cell further comprises an electrode assembly, which is accommodated in the accommodation cavity, and the electrode assembly comprises a positive electrode sheet and a negative electrode sheet, wherein: the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer disposed on the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises 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; and/or the negative electrode sheet comprises a negative electrode current collector and a carbonaceous coating disposed on the negative electrode current collector, the carbonaceous coating comprises a carbonaceous material, and the carbonaceous material comprises one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes. The risk of gas generation caused by the electrode material can be reduced.

In one embodiment, 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 channel of the valve cavity, and the valve core is configured to open the air inlet channel under the action of the gas inside the shell. In this way, the gas is discharged easily.

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; the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged. This can improve the connection strength of the breathable membrane assembly and reduce the risk of deformation of the breathable membrane.

In one embodiment, 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 wall portion is provided with a first exhaust hole, 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 through hole segment connects the inside of the shell with the outside of the shell, the first hole segment is located on a side of the through hole segment away from the inside 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, which is conducive to the assembly of the one-way valve.

In one embodiment, at least part of the valve body of the one-way valve protrudes from the outer surface; the wall portion has a first sinking platform that is recessed relative to the inner surface, the first sinking platform is arranged around the first exhaust hole, and the breathable membrane assembly is at least partially accommodated in the first sinking platform, so that the installation height of the exhaust assembly can be reduced.

In one embodiment, at least part of the valve body of the one-way valve protrudes from the outer surface of the wall; the first exhaust hole further includes a second hole segment, and along the thickness direction of the wall, the second hole segment is located between the through hole segment and the first hole segment, the aperture of the second hole segment is smaller than the aperture of the first hole segment, and the aperture of the second hole segment is larger than the aperture of the through hole segment, the air permeable membrane assembly is at least partially accommodated in the second hole segment, and the air permeable membrane assembly is located on the side of the one-way valve facing the wall, which is convenient for assembling the exhaust assembly.

In one embodiment, the one-way valve includes a valve body, at least part of which protrudes from the inner surface of the wall portion, the valve body includes a valve seat and a valve cover, the valve seat includes a seat bottom wall and a seat side wall connected to the seat bottom wall; the valve cover is arranged at one end of the valve seat away from the seat bottom wall, the valve cover, the seat side wall and the seat bottom wall are enclosed to form a valve cavity, and the valve seat is provided with an air inlet of the valve cavity; wherein the air permeable membrane assembly is arranged on a side of the seat bottom wall away from the valve cavity; or the air permeable membrane assembly is arranged on a side of the seat bottom wall facing the valve cavity. The installation height of the exhaust assembly can be reduced.

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.

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.

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

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 paying any creative work.

FIG1 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

FIG2 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

FIG3 is a schematic cross-sectional view of a one-way valve according to one or more embodiments;

FIG4 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments;

FIG5 is a front schematic view of a one-way valve according to one or more embodiments;

FIG6 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

FIG7 is a schematic cross-sectional view of a one-way valve according to one or more embodiments;

FIG8 is a schematic front view of a one-way valve according to one or more embodiments;

FIG9 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

FIG10 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

FIG11 is a schematic cross-sectional view of a breathable membrane assembly according to one or more embodiments;

FIG12 is a schematic diagram of a partial cross-sectional structure of an end cap according to one or more embodiments;

FIG13 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

FIG. 14 is a partial front view of a battery cell according to one or more embodiments;

FIG15 is a schematic diagram of a partial cross-sectional structure of an end cap according to one or more embodiments;

FIG16 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

FIG. 17 is a partial front view of a battery cell according to one or more embodiments;

FIG. 18 is an exploded view of an exhaust assembly according to one or more embodiments;

FIG. 19 is a schematic cross-sectional view of an exhaust assembly according to one or more embodiments.

FIG. 20 is an exploded view of an exhaust assembly according to one or more embodiments;

FIG21 is a schematic cross-sectional view of an exhaust assembly according to one or more embodiments;

FIG. 22 is an exploded view of an exhaust assembly according to one or more embodiments;

FIG. 23 is a schematic cross-sectional view of an exhaust assembly according to one or more embodiments.

FIG24 is a schematic diagram of an exploded structure of a battery according to one or more embodiments;

FIG. 25 is a schematic diagram of the structure of a vehicle according to one or more embodiments.

In the attached figure:

1000, vehicle; 300, motor; 200, controller; 100, battery; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, end cap; 21a, outer surface; 21b, inner surface; 291, first exhaust hole; 22, housing; 221, accommodating chamber; 23, electrode assembly; 24, insulating member; 293, third exhaust hole; 25, electrode terminal; 90, exhaust assembly; 30, one-way valve; 31, valve body; 311, valve seat; 3111, first through hole; 3112, first sink; 3113, protrusion; 3114, fourth through hole; 3115, seat bottom wall; 3116, Seat side wall; 312, valve cover; 312a, convex part; 3121, cover top wall; 3122, cover side wall; 31221, second through hole; 3123, fifth through hole; 313, valve cavity; 313a, air inlet; 313b, air outlet; 313c, first exhaust gap; 32, valve core; 321, blocking member; 3211, sealing part; 3212, pressing part; 322, elastic member; 40, breathable membrane assembly; 41, breathable membrane; 42, metal member; 491, first air hole; 43, backing member; 70, pressure relief mechanism; T1, first annular table; T2, second annular table; T3, transition surface; S1, first sink.

DETAILED DESCRIPTION

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.

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.

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.

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.

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.

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 interpreted 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.

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.

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.

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.

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.

Please refer to FIG. 1, which is a schematic diagram of the exploded structure of a battery cell according to one or more embodiments. A battery cell 20 is provided, and the battery cell 20 is the smallest unit of a battery. As shown in FIG. 1, the battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

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. In some embodiments, the end cap 21 may also be provided with a pressure relief mechanism 70 for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value. The material of the end cap 21 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating member 24 may also be provided on the inner side of the end cap 21, and the insulating member 24 may 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 may be plastic, rubber, etc.

The shell 22 is a component used to cooperate with the end cap 21 to form a housing chamber 221 of the battery cell 20, wherein the formed internal space 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.

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 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 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, 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.

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.

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.

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.).

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 the sodium battery, the polyanion compound includes a compound based on phosphoric acid and fluorophosphate. The compound based on phosphoric acid 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. The polyanion compound includes one or more of sodium vanadium trifluorophosphate Na ₃ V ₂ (PO ₄ ) ₂ F ₃ , sodium vanadium fluorophosphate NaVPO ₄ F, sodium vanadium phosphate Na ₃ V ₂ (PO ₄ ) ₃ , Na ₄ Fe ₃ (PO ₄ ) ₂ P ₂ O ₇ , NaFePO ₄ , and Na ₃ V ₂ (PO ₄ ) ₃ . The Prussian blue compound is Na _x MM(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 iron manganese phosphate.

In one embodiment, the negative electrode plate includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector, and the negative electrode active layer includes a negative electrode active material. In this embodiment, the battery cell is an ion battery, and during the battery charging and discharging process, active ions (such as Li ⁺ , Na ⁺ ) are embedded/de-embedded in the negative electrode active material.

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.

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.).

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.

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, and an aluminum metal battery. This type of battery can also be called a "negative electrode-free battery". During the charging process, sodium metal is formed by depositing active ions (such as Na ⁺ ) released from the positive electrode active material onto the negative electrode current collector. The provision of a carbonaceous coating facilitates more uniform metal deposition. Carbonaceous materials include one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

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.

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.

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

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.

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

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.

In one embodiment, in the sodium battery, the electrolyte salt includes sodium hexafluorophosphate (NaPF ₆ ), sodium bis(fluorosulfonyl)imide (NaFSI), sodium trifluoromethanesulfonate (CF ₃ NaO ₃ S), sodium sulfide (Na ₂ S) and the like. The lithium battery includes at least one lithium salt selected from the group consisting of lithium perchlorate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalatoborate, lithium tetrafluoroborate and lithium trifluoromethanesulfonate.

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.

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.

As the battery is charged and discharged, some side reactions will produce gas. If the gas produced by the battery is not discharged in time, the internal pressure of the battery will increase. Excessive internal pressure will have a negative impact on the performance and appearance of the battery. For example, in severe cases, it will have a destructive effect on the performance and appearance of the battery, such as leakage, bulging, increased internal resistance of the battery, and shortened discharge time and cycle life. In addition, there are some abnormal operations of the battery during use, including overcharging, over-discharging, internal failure, etc. In this case, the chemical reaction inside the battery may be uncontrolled, accompanied by violent release of gas, and even cause thermal runaway of the battery. Battery thermal runaway 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 to catch fire and explode.

Research has found that electrolyte is one of the key factors affecting gas production behavior. On the one hand, the electrolyte contains some highly active organic matter, which is prone to oxidation reaction on the positive electrode side or reduction reaction on the negative electrode side to produce gas. On the other hand, the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode. In order to achieve rapid migration of ions, the electrolyte is generally required to have a higher ionic conductivity. However, higher ionic conductivity will make the electrolyte components more active and more prone to gas production. Therefore, it is necessary to balance the relationship between battery gas production and ionic conductivity.

Please refer to FIG. 2, which is a 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 present application discloses a battery cell 20, which includes a shell and an exhaust assembly 90. The shell has a wall portion and a receiving cavity 221. The exhaust assembly 90 is arranged on the wall portion, and the exhaust assembly 90 is used to exhaust the gas inside the shell. The setting of the exhaust assembly 90 can timely discharge the gas inside the battery cell to the outside of the shell, so that the air pressure inside the battery cell is maintained at a normal level, which can improve the safety performance of the battery and greatly increase the battery life.

In this embodiment, the battery cell 20 further includes an electrolyte, which fills the accommodating cavity 221. The conductivity of the electrolyte is: 2ms/cm≤conductivity≤16ms/cm, and the exhaust rate of the exhaust assembly 90 is: 0.6mL/day≤exhaust rate≤10.0mL/day.

Conductivity is the ability of a solution to conduct electric current, expressed in numbers. The conductivity of an electrolyte depends on the concentration of mobile ions and the rate at which they migrate under a given electric field. High conductivity enables rapid ion migration, improving the charging capacity and energy density of the entire battery cell. However, electrolyte components with high conductivity are more susceptible to oxidation/reduction reactions during the charge and discharge process, causing the battery cell to produce more gas, leading to increased internal pressure in the battery and a series of adverse consequences. If a low-conductivity electrolyte is used to balance gas production, charging capacity and energy density will be lost.

The conductivity of the electrolyte generally refers to the reciprocal of the resistance of one cubic centimeter of liquid at 25°C, expressed in Ω ^-1 ·cm ^-1 or S/cm.

Conductivity test principle: The conductivity of a solution is related to the resistance value of the solution. A large resistance value indicates poor conductivity, while a small resistance value indicates good conductivity. According to Ohm's law, at a constant temperature, the resistance value of a solution is inversely proportional to the vertical cross-sectional area of the electrode and directly proportional to the distance between the electrodes. The unit of resistance is ohm (Ω); the unit of resistivity is ohm (Ω.M).

National standards for parameter testing:

The conductivity of the electrolyte can be measured using instruments and methods known in the art, for example, according to the HG/T4067-2015 standard.

Test method:

(1) Densitometer method, also known as arbitration method.

The instrument measurement temperature was set to 20°C, the sample was injected into the measurement cell of the instrument, the measurement was performed and the data was read.

(2) Density meter method

Use a dry, clean, corrosion-resistant sample bottle to take about 100 mL of sample, seal it in a constant temperature water bath at 25℃±0.5℃, shake it from time to time, and when the sample temperature is constant, replace the sample bottle cap with a rubber stopper with an electrode. When the temperature is within the range of 25℃±0.5℃, read the data in the conductivity meter, which is the conductivity of the sample being tested.

The exhaust rate of the exhaust assembly is defined as the volume of gas exhausted by the battery cell in one day. The greater the exhaust rate, the more conducive it is to the exhaust of gas in the battery cell. However, the existence of the exhaust assembly 90 reduces the sealing of the battery system to a certain extent, and external water vapor can easily enter the interior of the shell through the exhaust assembly 90, resulting in reduced battery performance. Therefore, it is not possible to design an exhaust assembly 90 with a relatively large exhaust rate in order to meet the exhaust requirements.

The test principle of exhaust rate: the test is based on GB/T1038-2000 standard. Specifically, the exhaust assembly separates the low-pressure chamber and the high-pressure chamber. The high-pressure chamber is filled with about 10 ⁵ Pa (i.e. 0.1MPa) of experimental gas. The volume of the low-pressure chamber is known. After the sample is sealed, the air in the low-pressure chamber is pumped to near zero value (i.e. vacuum) with a vacuum pump. The pressure increment ΔP in the low-pressure chamber is measured with a manometer to determine the amount of gas that passes through the high-pressure membrane (sheet) to the low-pressure chamber as a function of time, but the initial stage in which the gas permeation rate changes with time should be excluded. The gas permeation amount and gas permeation coefficient can be calculated by the computer of the instrument according to the prescribed program and then output to a floppy disk or printed on a recording paper, or calculated according to the test value.

In the present application, the gas production behavior of electrolytes with different conductivities is fully studied, and exhaust components with different exhaust rates are provided for battery cells with electrolytes with different conductivities; the contradiction between high conductivity requirements and high gas production can be balanced; at the same time, for some battery systems that do not require high conductivity, there is no need to use exhaust components with large exhaust capacity, so as to reduce the impact of external water vapor intrusion on the battery during the exhaust process.

In one embodiment, when the conductivity of the electrolyte system in the battery cell is within the range of 2ms/cm-16ms/cm, the exhaust rate of the exhaust assembly on the battery cell can be controlled at 0.6mL/day-10.0mL/day, which can meet the most basic ventilation requirements and reduce the intrusion of external water vapor.

In one embodiment, the conductivity of the electrolyte is: 8 ms/cm≤conductivity≤16 ms/cm; the exhaust rate of the exhaust component is: 3.3 mL/day≤exhaust rate≤10.0 mL/day.

At this time, the conductivity of the electrolyte is relatively high, the ion migration speed is relatively fast, and the gas production of the battery cell is relatively large. Therefore, matching the exhaust component with a larger exhaust rate can discharge the gas in time.

Furthermore, the exhaust rate of the exhaust assembly can also be 4.5 mL/day to 8.0 mL/day, which can make the exhaust rate and electrolyte conductivity match more accurately, and can improve the charging capacity and energy density of the battery cell while taking into account the safety performance and service life of the battery cell.

In other embodiments, the combination scheme of electrolytes with different conductivities and exhaust components can also be: the electrolyte conductivity is 8ms/cm-10ms/cm and the exhaust rate of the exhaust component is 3.3mL/day-5.0mL/day; the electrolyte conductivity is 10ms/cm-12ms/cm and the exhaust rate of the exhaust component is 5.0mL/day-6.7mL/day; the electrolyte conductivity is 11ms/cm-14ms/cm and the exhaust rate of the exhaust component is 4.5mL/day-9.0mL/day; the electrolyte conductivity is 14ms/cm-16ms/cm and the exhaust rate of the exhaust component is 8.4mL/day-10.0mL/day.

In one embodiment, the conductivity of the electrolyte is: 2 ms/cm≤conductivity≤8 ms/cm; the exhaust rate of the exhaust component is: 0.6 mL/day≤exhaust rate≤5.0 mL/day.

At this time, the conductivity of the electrolyte is low, the ion migration speed is slow, and the gas production of the battery cell is small. Therefore, matching the exhaust component with a smaller exhaust rate can timely exhaust the gas inside the battery while reducing the probability of external impurities (air, moisture, dust, etc.) entering the battery cell.

Furthermore, the exhaust rate of the exhaust assembly can also be 1.3 mL/day to 3.9 mL/day, which can make the exhaust rate and the electrolyte conductivity match more accurately, taking into account the safety performance and service life of the battery cell.

In other embodiments, the combination scheme of electrolytes with different conductivities and exhaust components can also be: the electrolyte with a conductivity of 2ms/cm-4ms/cm and an exhaust rate of the exhaust component of 0.6mL/day-2.1mL/day; the electrolyte with a conductivity of 4ms/cm-6ms/cm and an exhaust rate of the exhaust component of 1.3mL/day-3.9mL/day; the electrolyte with a conductivity of 6ms/cm-8ms/cm and an exhaust rate of the exhaust component of 3.6mL/day-5.0mL/day.

According to some embodiments of the present application, the exhaust assembly 90 includes a breathable membrane assembly 40 , the breathable membrane assembly 40 includes a breathable membrane 41 , and the breathable membrane 41 is configured to allow gas inside the battery cell 20 to be discharged through the breathable membrane 41 .

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 90, the battery cell 20 can discharge internal gas through the breathable membrane 41 in a sealed state, and the internal gas of the battery cell is discharged to the outside of the shell in time, so that the gas pressure inside the battery cell will not be too high, and the pressure relief mechanism will not open the valve prematurely, which can greatly improve the battery life.

Furthermore, the breathable membrane 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 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 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 can be selected from polymer materials, such as polytetrafluoroethylene, polypropylene, etc. In addition, since the generation of gas inside the battery will cause the internal pressure to rise rapidly, the breathable membrane needs to have certain mechanical strength and elasticity.

Among them, the air permeability rate of the breathable membrane assembly 40 depends on the characteristics of the breathable membrane 41. A polymer membrane with a certain porosity can be selected as the breathable membrane 41, and materials with different porosities can be used to prepare breathable membranes 41 with different air permeability rates. For example, the air permeability rate of the breathable membrane 41 can be 0.5mL/day, 1.0mL/day, 1.5mL/day, 2.5mL/day, 3.0mL/day, 3.5mL/day, 4.0mL/day, 5.0mL/day, 6.5mL/day, 8.5mL/day, 9.0mL/day, 9.5mL/day, 10.0mL/day. The air permeability test conditions of the breathable membrane are 23°C, 0%RH (humidity is 0%), and 0.1MPa air pressure.

According to some embodiments of the present application, the breathable membrane includes a first breathable membrane, and the breathability rate of the first breathable membrane is 3-4 mL/day.

According to some embodiments of the present application, the breathable membrane includes a second breathable membrane, and the breathability rate of the second breathable membrane is 9-10 mL/day.

According to some embodiments of the present application, the exhaust assembly 90 includes a one-way valve 30, which is configured to actuate and release the gas inside the battery cell 20 when the gas pressure inside the battery cell 20 reaches a threshold value. In other words, the one-way valve 30 is used to exhaust the gas inside the shell, that is, the one-way valve 30 can be opened in one direction to exhaust, so that the gas inside the shell can be discharged to the outside of the shell through the one-way valve 30.

Please refer to Figure 3, which is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments. According to some embodiments of the present application, the one-way valve 30 includes a valve body 31 and a valve core 32, the valve body 31 has a valve cavity 313 inside, the valve body 31 is provided with an air inlet 313a and an air outlet 313b, the air inlet 313a is used to connect the valve cavity 313 with the inside of the shell, and the air outlet 313b is used to connect the valve cavity 313 with the outside of the shell; the valve core 32 is arranged in the valve cavity 313, the valve core 32 is used to block the air inlet channel of the valve cavity 313, and the valve core 32 is configured to open the air inlet channel under the action of the gas inside the shell and release the gas inside the battery cell.

As shown in FIG. 3 , FIG. 3 (a) is a schematic diagram of the one-way valve in the non-opening state; FIG. 3 (b) is a schematic diagram of the one-way valve in the opening state. The valve core 32 includes an elastic member 322 and a blocking member 321. The elastic member 322 provides an elastic force F1 to the blocking member 321, and the blocking member 321 is pressed to block the air inlet 313a. When the force F2 of the gas inside the shell on the blocking member 321 is greater than the elastic force F1 of the elastic member, the gas inside the shell can overcome the elastic force of the elastic member and push the blocking member 321 to open the air inlet 313a, so as to allow the gas inside the shell to enter the valve cavity 313 and then be discharged from the outside of the shell through the air outlet 313b. On the contrary, after the gas inside the shell is discharged and the force F2 of the gas inside the shell on the blocking member 321 is less than the elastic force F1 of the elastic member, the elastic member 322 can drive the blocking member 321 to reset to block the air inlet 313a.

Specifically, when the air pressure inside the shell increases to a certain value P1, the force F2 applied by the air pressure to the lower surface of the sealing member 321 is greater than the spring compression force F1, and the sealing interface fails. The gas inside the shell is discharged to the outside of the shell through the channel inside the valve body 31. As the gas inside the shell is discharged, the internal air pressure drops. When the air pressure reaches a certain value P2, the valve body 31 is closed to achieve sealing. The valve body 31 can be repeatedly opened and closed for exhaust and venting, so that the air pressure inside the shell is maintained between P1-P2, thereby preventing the pressure relief mechanism from opening the valve prematurely due to excessive air pressure inside the shell. In other words, a one-way valve requires a certain pressure threshold to open the valve.

According to some embodiments of the present application, the opening pressure of the valve core is greater than or equal to 0.2MPa; further, greater than or equal to 0.4MPa; and further, greater than or equal to 0.8MPa. For example, the opening pressure may 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, etc.

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.

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.

According to some embodiments of the present application, the structure of the exhaust assembly can be selected according to the required exhaust rate of the exhaust assembly; the exhaust assembly can include a breathable membrane assembly, that is, the breathable membrane assembly is selected as the exhaust assembly; the exhaust assembly can include a one-way valve, that is, the one-way valve is selected as the exhaust assembly. In other embodiments, the exhaust assembly can also include both a one-way valve and a breathable membrane assembly.

According to some embodiments of the present application, the exhaust assembly uses a breathable membrane assembly or a one-way valve. For example, a breathable membrane assembly including a first breathable membrane may be used alone, or a breathable membrane assembly including a second breathable membrane may be used alone, or a one-way valve having an opening pressure greater than 0.4 MPa may be used alone; or a breathable membrane assembly including a second breathable membrane may be used alone, or a one-way valve having an opening pressure greater than 0.2 MPa may be used alone.

According to some embodiments of the present application, the exhaust assembly 90 includes a breathable membrane assembly 40 and a one-way valve 30, and the wall portion has a first exhaust hole 291, the first exhaust hole 291 connects the inside of the outer shell with the outside of the outer shell, and the battery cell 20 is configured so that the gas exhausted through the first exhaust hole 291 flows through the one-way valve 30 and the breathable membrane assembly 40.

As shown in FIG2 , the first exhaust hole 291 connects the inside of the shell with the outside of the shell, that is, the first exhaust hole 291 is a through hole, and the gas inside the shell of the battery cell 20 can be discharged through the first exhaust hole 291 to regulate the pressure inside the shell of the battery cell 20. The battery cell 20 is configured so that the gas discharged through the first exhaust hole 291 flows through the one-way valve 30 and the breathable membrane assembly 40, which means that when the gas flows through the first exhaust hole 291 to be discharged, it also flows through the one-way valve 30 and the breathable membrane assembly 40 belonging to the same exhaust assembly 90; or the exhaust path of the gas needs to flow through the one-way valve 30 and the breathable membrane assembly 40 at the same time. In other words, the one-way valve 30 and the breathable membrane assembly 40 in the same exhaust assembly 90 are connected in series, and when the gas flows through the exhaust assembly 90, it will flow through the one-way valve 30 and the breathable membrane assembly 40 in the exhaust assembly 90 in sequence. It may be that the gas first flows through the breathable membrane assembly 40 and then flows through the one-way valve 30; it may also be that the gas first flows through the one-way valve 30 and then flows through the breathable membrane assembly 40; the flow order can be set as needed, but both structures need to flow through, rather than part of the gas only flowing through the one-way valve 30 for discharge and the other part of the gas only flowing through the breathable membrane assembly for discharge. It may be that one first exhaust hole 291 is set on the end cover 21, or it may be that multiple first exhaust holes 291 are set on the end cover 21. When there are multiple first exhaust holes 291, each first exhaust hole 291 is equipped with a set of exhaust components 90, and when the gas is discharged through the first exhaust hole 291, it will flow through the one-way valve 30 and the breathable membrane assembly 40 in the exhaust component 90 set at the first exhaust hole 291.

In this embodiment, by setting the breathable membrane assembly 40 and the one-way valve 30 in series, the presence of the one-way valve 30 can control the system to not be in a breathable state all the time, but the one-way valve 30 will be activated to exhaust gas only when the accumulation reaches a certain threshold, which can protect the sealing of the battery cell 20 system and reduce the probability of external water vapor entering the battery cell 20 system; at the same time, the presence of the breathable membrane 41 can, on the one hand, prevent the overflow of the electrolyte, and on the other hand, when the one-way valve 30 is open, the breathable membrane 41 can realize the closure of the battery system, so that the battery cell 20 can discharge the internal gas through the breathable membrane 41 and the one-way valve 30 in a sealed state, thereby improving the disadvantage that when the one-way valve 30 is exhausted, the battery cell 20 system is in an open state and is easily invaded by external water vapor.

According to some embodiments of the present application, when the exhaust assembly 90 includes a breathable membrane assembly 40 and a one-way valve 30, and the breathable membrane assembly 40 and the one-way valve 30 are connected in series, breathable membranes 41 with different breathability rates and one-way valves 30 with different opening pressures can be used.

According to some embodiments of the present application, the opening pressure of the one-way valve 30 is greater than or equal to 0.4 MPa, the breathable membrane assembly 40 includes a second breathable membrane, and the breathability rate of the second breathable membrane is 9-10 mL/day.

Please refer to FIG. 4, which is a 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 exhaust assembly 90 includes a breathable membrane assembly 40 and a one-way valve 30, and the wall portion has a first exhaust hole 291 and a third exhaust hole 293 arranged at intervals, and the first exhaust hole 291 and the third exhaust hole 293 are connected to the inside of the shell and the outside of the shell respectively, and the battery cell 20 is configured so that the gas exhausted through the first exhaust hole 291 flows through the one-way valve 30, and the gas exhausted through the third exhaust hole 293 flows through the breathable membrane assembly 40.

The first exhaust hole 291 connects the inside of the shell with the outside of the shell, and the third exhaust hole 293 also connects the inside of the shell with the outside of the shell, that is, the two are two independent holes that can exhaust gas at the same time to adjust the pressure inside the shell of the battery cell 20. The end cover 21 may be provided with one first exhaust hole 291 and one third exhaust hole 293, or the end cover 21 may be provided with multiple first exhaust holes 291 and multiple third exhaust holes 293. The battery cell 20 is configured such that the gas discharged through the first exhaust hole 291 flows through the one-way valve 30, and the gas discharged through the third exhaust hole 293 flows through the breathable membrane assembly 40, which means that the gas can be discharged from the battery cell 20 through the first exhaust hole 291 and the third exhaust hole 293 at the same time, and flows through the one-way valve 30 when flowing through the first exhaust hole 291, and flows through the breathable membrane assembly 40 when flowing through the third exhaust hole 293; or the one-way valve 30 and the breathable membrane assembly 40 are connected in parallel, and when the gas flows through the exhaust assembly 90, it can flow through the one-way valve 30 and the breathable membrane assembly 40 in the exhaust assembly 90 at the same time, that is, part of the gas only flows through the one-way valve 30 for discharge, and the other part of the gas only flows through the breathable membrane assembly 40 for discharge. When there are multiple first exhaust holes 291, each first exhaust hole 291 is equipped with a one-way valve 30; when there are multiple third exhaust holes 293, each third exhaust hole 293 is equipped with a breathable membrane assembly 40.

In this embodiment, the breathable membrane assembly 40 is arranged in parallel with the one-way valve 30. When the internal air pressure of the battery cell 20 is low, the gas is mainly exhausted through the breathable membrane assembly 40. When the internal air pressure of the battery cell 20 is high, the gas is mainly exhausted through the one-way valve 30. The problem of frequent opening of the one-way valve 30 caused by unstable internal air pressure of the battery cell 20 is reduced, the invasion of external water vapor is reduced, and the sealing of the battery cell 20 system is improved; at the same time, when the air pressure is low, the gas can be discharged in time through the breathable membrane assembly 40; it is conducive to the exhaust assembly 90 to adapt to different air pressure environments, and the flexibility of the exhaust assembly 90 is improved.

According to some embodiments of the present application, when the exhaust assembly 90 includes a breathable membrane assembly 40 and a one-way valve 30, and the breathable membrane assembly 40 and the one-way valve 30 are connected in parallel, breathable membranes 41 with different breathability rates and one-way valves 30 with different opening pressures can be used in combination.

According to some embodiments of the present application, the opening pressure of the one-way valve 30 is greater than or equal to 0.4 MPa, the breathable membrane assembly 40 includes a second breathable membrane, and the breathability rate of the second breathable membrane is 3-4 mL/day.

According to some embodiments of the present application, the exhaust assembly is configured to be a breathable membrane assembly and a one-way valve in series, or a breathable membrane assembly and a one-way valve in parallel. For example, the exhaust assembly may be a breathable membrane assembly with a second breathable membrane and a one-way valve with an opening pressure greater than 0.4 MPa in series.

According to some embodiments of the present application, the exhaust assembly is configured to be a breathable membrane assembly and a one-way valve in series, or a breathable membrane assembly and a one-way valve in parallel. For example, the exhaust assembly may be a breathable membrane assembly with a first breathable membrane and a one-way valve with an opening pressure greater than 0.8 MPa in parallel.

In other embodiments, the one-way valve 30 and the breathable membrane assembly 40 in the exhaust assembly may be mixed, that is, the exhaust assembly may include both the one-way valve 30 and the breathable membrane assembly 40 connected in series and the one-way valve 30 and the breathable membrane assembly 40 connected in parallel.

According to some embodiments of the present application, the electrolyte conductivity and exhaust assembly matching scheme provided in the present application can be applicable to alkali metal batteries. They can be lithium metal batteries, sodium metal batteries, potassium metal batteries, zinc metal batteries, aluminum metal batteries, etc. Of course, they are also applicable to other types of batteries, such as lithium-ion batteries, sodium-ion batteries, etc.

According to some embodiments of the present application, the gas production rate of the battery used in the combination scheme of electrolyte conductivity and exhaust components provided in the present application is: the gas production rate of the battery cell is: 0.006mL/Ah/D≤gas production rate≤0.066mL/Ah/D.

Optionally, the gas production rate of the battery cell is: 0.013mL/Ah/D≤gas production rate≤0.026mL/Ah/D. At this time, the gas production rate of the battery cell is small, and the electrolyte and exhaust components are matched, the conductivity of the electrolyte is 2ms/cm-8ms/cm, and the exhaust rate of the exhaust component is 0.6mL/day-5.0mL/day.

Optionally, the gas production rate of the battery cell is: 0.045mL/Ah/D≤gas production rate≤0.060mL/Ah/D. At this time, the gas production rate of the battery cell is relatively large, and the electrolyte and exhaust components are matched, the conductivity of the electrolyte is 8ms/cm-16ms/cm; the exhaust rate of the exhaust component is 3.3mL/day-10.0mL/day.

According to some embodiments of the present application, the residual space V of the battery used in the matching scheme of electrolyte conductivity and exhaust assembly provided in the present application is 0.5mL/Ah≤V≤3.5mL/Ah, which may be 0.5mL/Ah≤V≤2mL/Ah, 0.8mL/Ah≤V≤1.5mL/Ah, 2.0mL/Ah≤V≤3.5mL/Ah, 2.5mL/Ah≤V≤3.0mL/Ah, etc. The suitable exhaust assembly may be selected in combination with the capacity and residual space of the battery.

The residual space is defined as the volume space remaining inside the shell of the battery cell after the shell is filled with liquid.

Test conditions: Baking cells, electrolyte with known density, vacuum box, injector, and two aluminum plate fixtures.

Steps:

1. Weigh the quality of the battery cell after baking and record it;

2. Use a clamp to clamp the battery core to prevent swelling and deformation;

3. Align the nozzle of the injector with the filling port of the battery cell, pour in a certain amount of electrolyte, place it in a vacuum box to evacuate, and leave it at room temperature for more than 24 hours until the battery cell is filled;

4. After fully filling, remove the fixture and weigh it, and record the mass of the fully filled battery cell;

Data processing: The mass difference before and after the full filling experiment is subtracted from the amount of electrolyte retained, and the residual space volume of the battery cell is converted by the electrolyte density.

According to some embodiments of the present application, the electrolyte of the battery used in the combination scheme of electrolyte conductivity and exhaust component provided in the present application includes one or more of chain ethers, ethylene glycol dimethyl ether and its derivatives, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and cyclic ethers.

According to some embodiments of the present application, the positive electrode plate of the battery used in the combination scheme of electrolyte conductivity and exhaust assembly provided in the present application includes a positive electrode collector and a positive electrode active layer arranged on the positive electrode collector, the positive electrode active layer includes a positive electrode active material, and the positive electrode active 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.

According to some embodiments of the present application, the negative electrode plate of the battery used in the combination scheme of electrolyte conductivity and exhaust assembly provided in the present application includes a negative electrode current collector and a carbon-containing coating arranged on the negative electrode current collector, the carbon-containing coating includes a carbon-containing material, and the carbon-containing material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

In one embodiment, the exhaust assembly 90 is disposed on the wall portion of the outer shell of the battery cell 20, and the outer shell includes an end cap 21 and a shell 22, and the wall portion may be the wall of the end cap 21 or the wall of the shell 22. That is, the exhaust assembly 90 may be disposed on the end cap 21 or on the shell 22. In other words, the wall portion for mounting the exhaust assembly 90 may be the end cap 21 of the outer shell or a wall of the shell 22 of the outer shell. Exemplarily, the wall portion is the end cap 21. Of course, the structure of the battery cell is not limited thereto. In other embodiments, the wall portion may also be the bottom wall of the shell and the end cap disposed opposite to each other, and the wall portion may also be the side wall of the shell and the end cap adjacent to and connected to each other. In one embodiment, the exhaust assembly is preferably located on the wall with the top facing upward when the battery cell is in a placed state. The following will take the wall portion as the wall of the end cap 21 as an example to illustrate the present application scheme, but this should not limit the present application.

Please refer to Figures 5, 6 and 7. Figure 5 is a front view of a one-way valve according to one or more embodiments, Figure 6 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments, and Figure 7 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the end cover 21 includes 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 one-way valve 30 is arranged on the end cover 21, and the valve body 31 of the one-way valve 30 faces the outside of the shell and at least part of the valve body 31 protrudes from the outer surface 21a of the end cover 21.

In this embodiment, the one-way valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve cavity 313 inside, and the valve core 32 is arranged in the 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. The valve seat 311 is provided with an air inlet of the valve cavity 313 to connect the valve cavity 313 with the inside of the shell; the valve cover 312 is provided with an air outlet of the valve cavity 313 to connect the valve cavity 313 with the outside of the shell. The valve core 32 is used to block the air inlet channel of the valve cavity 313. The valve core 32 is configured to open the air inlet channel under the action of the gas inside the shell and release the gas inside the battery cell.

Please continue to refer to FIG. 5 and FIG. 6 , 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 is the first through hole 3111, that is, the first through hole 3111 is used as the air inlet of the valve cavity 313. The cover side wall 3122 has a second through hole 31221 penetrating the cover side wall 3122, and the air outlet is the second through hole 31221, that is, the second through hole 31221 is used as the air outlet of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery to the outside.

According to some embodiments of the present application, along the direction away from the cover top wall 3121, the second through hole 31221 extends to the end of the cover side wall 3122. As shown in FIG6, the direction away from the cover top wall 3121 is the direction from the cover top wall 3121 to the valve seat 311 (the 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, and along the X direction, the cover side wall 3122 is directly hollowed out to the bottom of the cover side wall 3122. In a further embodiment, along the X direction, the lower opening surface of the second through hole 31221 can be flush with the sealing surface of the blocking member 321. Through this arrangement, when the one-way valve 30 is opened to 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.

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 is in an open state is shortened, so as to reduce the invasion of external water vapor into the battery system during the valve opening period.

Please refer to Figures 8, 9 and 10. Figure 8 is a front view of a one-way valve according to one or more embodiments, and Figure 9 is a schematic diagram of the exploded structure of a one-way valve according to one or more embodiments. Figure 10 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the end cover 21 includes 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; the one-way valve 30 is arranged on the end cover 21, and the valve body 31 of the one-way valve 30 faces the inside of the shell and at least part of the valve body 31 protrudes from the inner surface 21b of the end cover 21. That is, the valve body 31 extends into the shell along the thickness direction of the end cover 21.

In this embodiment, the one-way valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve cavity 313 inside, and the valve core 32 is arranged in the valve cavity 313. The valve body 31 includes a valve seat 311 and a valve cover 312. The valve seat 311 includes a seat bottom wall 3115 and a seat side wall 3116 connected to the seat bottom wall 3115. The valve cover 312 is arranged at one end of the valve seat 311 away from the seat bottom wall 3115. The valve cover 312, the seat side wall 3116 and the seat bottom wall 3115 enclose the valve cavity 313. The valve seat 311 is provided with an air inlet of the valve cavity 313 to connect the valve cavity 313 with the inside of the shell. The valve core 32 is used to block the air inlet channel of the valve cavity 313. The valve core 32 is configured to open the air inlet channel under the action of the gas inside the shell and release the gas inside the battery cell.

Please continue to refer to Figures 8, 9 and 10. According to some embodiments of the present application, the valve seat 311 has a fourth through hole 3114 that penetrates the bottom wall 3115 of the seat, and the air inlet is the fourth through hole 3114, that is, the fourth through hole 3114 is used as the air inlet of the valve cavity 313. Of course, in other embodiments, the air inlet can also be provided on the outer peripheral surface of the portion of the valve body 311 extending into the shell. When the air inlet is provided on the outer peripheral surface of the portion of the valve body 311 extending into the shell, the setting direction of the valve core 32 will be changed accordingly, and the blocking member 321 is movably provided in the valve cavity 313 along the radial direction of the valve seat 311, so that the valve core blocks the air inlet.

Please continue to refer to Figures 8, 9 and 10. According to some embodiments of the present application, the gas outlet may be directly opened on the valve cover, that is, the gas outlet is a channel provided on the valve cover. Specifically, the valve cover 312 has a fifth through hole 3123 penetrating the valve cover 312, and the gas outlet is the fifth through hole 3123, that is, the fifth through hole 3123 is used as the gas outlet of the valve cavity 313. This arrangement can facilitate the outward transmission of gas inside the battery.

The fifth through hole 3123 provided on the valve cover 312 may be one or more. Exemplarily, in FIGS. 8 and 9, three fifth through holes 3123 are provided on the valve cover 312. Of course, in other embodiments, the fifth through holes 3123 provided on the valve cover 312 may also be two, four, five or six. As an example, there are multiple fifth through holes 3123 provided on the valve cover 312, and the multiple fifth through holes 3123 are arranged at equal intervals. As an example, the multiple fifth through holes 3123 are arranged at equal intervals around the center of the valve cover 312, so that the gas can flow out more smoothly.

Please refer to Figure 11, which is a 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 further includes a metal member 42, that is, the breathable membrane assembly 40 includes a breathable membrane 41 and a metal member 42, and the metal member 42 is used to support the breathable membrane 41. Specifically, the metal member 42 is provided with a first breathable hole 491, the breathable membrane 41 is provided on the metal member 42, and the breathable membrane 41 covers the first breathable hole 491.

The metal part 42 can support the breathable membrane 41 to protect the breathable membrane 41 from excessive deformation. At the same time, the metal part 42 can also serve as a medium for connecting other parts of the breathable membrane assembly 40. The breathable membrane 41 is connected to other parts through the metal part 42 to improve the stability of the connection. The metal part 42 is provided with at least one first air hole 491 as a release channel for the gas inside the battery so that the gas can pass through the metal part 42. The shape of the first air hole 491 includes geometric shapes such as circle, square, and ellipse. The metal part 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.

Please continue to refer to Figure 11. According to some embodiments of the present application, the breathable membrane assembly 40 also includes a backing member 43, that is, the breathable membrane assembly 40 includes a breathable membrane 41, a metal member 42 and a backing member 43, the breathable membrane 41 is arranged on the metal member 42, the backing member 43 is arranged between the breathable membrane 41 and the metal member 42, and the backing member 43 is used to support the breathable membrane 41 and allow gas to pass through the breathable membrane 41.

The backing member 43 can support the breathable membrane 41, so that the breathable membrane 41 is not easily deformed. 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.

Please continue to refer to Figure 11. According to some embodiments of the present application, the metal part 42 has a first annular table T1 and a second annular table T2 that 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.

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 .

By providing a recessed platform on the metal part 42, the surface of the breathable membrane 41 can be flush with the surface of the metal part 42, thereby reducing the overall height of the breathable membrane assembly 40, and further reducing the installation height of the breathable membrane assembly 40. In other embodiments, if the breathable membrane assembly 40 does not include a backing member 43, only the first annular table surface T1 can be provided to carry the breathable membrane 41. As shown in FIG. 11(b), in another embodiment, when the breathable membrane assembly 40 includes a backing member 43, only the first annular table surface T1 can be provided to carry 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 provision 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.

Please refer to Figures 12, 13 and 14. Figure 12 is a partial cross-sectional structural diagram of an end cap according to one or more embodiments; Figure 13 is a cross-sectional structural diagram of a battery cell according to one or more embodiments. Figure 14 is a front view of an end cap of a battery cell according to one or more embodiments.

According to some embodiments of the present application, the one-way valve 30 is arranged on the end cover 21, the valve body 31 of the one-way valve 30 faces the outside of the outer shell and at least part of the valve body 31 protrudes from the outer surface 21a of the end cover 21, and the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the inside of the outer shell; the one-way valve 30 and the breathable membrane assembly 40 are respectively and independently connected to the end cover 21.

According to some embodiments of the present application, the end cover 21 is provided with a first exhaust hole 291, the first exhaust hole 291 includes a through hole section 280 and a first hole section 281, the through hole section 280 and the first hole section 281 are arranged along the thickness direction of the end cover 21, the through hole section 280 connects the inside of the shell with the outside of the shell, the first hole section 281 is located on the side of the through hole section 280 away from the inside of the shell, the aperture of the first hole section 281 is larger than the aperture of the through hole section 280, the one-way valve 30 is at least partially accommodated in the first hole section 281, the valve body 31 of the one-way valve 30 faces the outside of the shell and at least part of the valve body 31 protrudes from the outer surface 21a of the end cover 21. As shown in FIG. 19, the first exhaust hole 291 is a countersunk hole that is 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.

According to some embodiments of the present application, the one-way valve 30 is welded to the end cover 21. As shown in FIG13 , the valve seat 311 of the one-way valve 30 can be welded to the end cover 21; 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.

According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41 and a metal part 42, the breathable membrane 41 is disposed on the metal part 42, the breathable membrane assembly 40 is disposed on the end cap 21, and the metal part 42 is connected to the end cap 21. That is, the breathable membrane 41 is connected to the end cap 21 through the metal part 42. The metal part 42 can be connected to the end cap 21 by welding, interference fit, etc. In this way, the connection strength between the breathable membrane assembly 40 and the end cap 21 can be enhanced.

Please continue to refer to Figures 13 and 14. According to some embodiments of the present application, the end cover 21 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 end cover 21 has a first sinker S1 that is recessed relative to the inner surface 21b. The first sinker S1 is arranged around the first exhaust hole 291, and the breathable membrane assembly 40 is at least partially accommodated in the first sinker S1.

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.

As shown in FIG. 14 , the breathable membrane 41 may be disposed on the side of the metal part 42 facing the inside of the housing; that is, the breathable membrane 41 is below the metal part 42. This arrangement can reduce the influence of the working environment of the battery cell 20 on the breathable membrane 41. In other embodiments, the breathable membrane 41 may be disposed on the side of the metal part 42 facing the outside of the housing, that is, the breathable membrane 41 is disposed between the metal part 42 and the end cover 21; this arrangement can reduce the erosion of the breathable membrane 41 by the electrolyte system.

Please refer to Figures 15, 16 and 17 in combination. Figure 15 is a schematic diagram of the partial cross-sectional structure of the end cover according to one or more embodiments; Figure 16 is a schematic diagram of the cross-sectional structure of a battery cell according to one or more embodiments; Figure 17 is a front view of the end cover of the battery cell according to one or more embodiments.

According to some embodiments of the present application, the one-way valve 30 is arranged on the end cover 21, the valve body 31 of the one-way valve 30 faces the outside of the outer shell and at least part of the valve body 31 protrudes from the outer surface 21a of the end cover 21, and the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the outside of the outer shell; the one-way valve 30 and the breathable membrane assembly 40 are respectively and independently connected to the end cover 21.

As mentioned above, the end cover 21 is provided with a first exhaust hole 291, the first exhaust hole 291 includes a first hole section 281, the one-way valve 30 is at least partially accommodated in the first hole section 281, and the valve body 31 of the one-way valve 30 faces the outside of the housing, and at least a portion of the valve body 31 protrudes from the outer surface 21a of the end cover 21. In this embodiment, the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the outside of the housing, at least a portion of the breathable membrane assembly 40 is accommodated in the first exhaust hole 291, and the breathable membrane assembly 40 is located on the side of the one-way valve 30 facing the end cover 21.

Specifically, the first exhaust hole 291 also includes a second hole segment 282. Along the thickness direction of the end cover 21, the second hole segment 282 is located between the through hole segment 280 and the first hole segment 281. The aperture of the second hole segment 282 is smaller than the aperture of the first hole segment 281, and the aperture of the second hole segment 282 is larger than the aperture of the through hole segment 280. The breathable membrane assembly 40 is at least partially accommodated in the second hole segment 282.

According to some embodiments of the present application, 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; the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged. The connector may be a sheet-like member or a metal member.

In one embodiment, the breathable membrane assembly 40 includes a breathable membrane 41 and a metal member 42 . The metal member 42 is provided with a first breathable hole 491 . The breathable membrane 41 is disposed on the metal member 42 and covers the first breathable hole 491 . The metal member 42 is welded to the end cover 21 .

According to some embodiments of the present application, the one-way valve 30 may be disposed on the end cover 21, the valve body 31 of the one-way valve 30 faces the inside of the housing and at least a portion of the valve body 31 protrudes from the inner surface 21b of the end cover 21, the breathable membrane assembly 40 is connected to the one-way valve 30, and the one-way valve 30 is connected to the end cover 21. That is, the one-way valve 30 and the breathable membrane assembly 40 are first combined and then connected to the end cover 21.

Please refer to Figures 18 and 19. Figure 18 is a schematic diagram of the exploded structure of the exhaust assembly according to one or more embodiments; Figure 19 is a schematic diagram of the cross-sectional structure of the exhaust assembly according to one or more embodiments. According to some embodiments of the present application, the breathable membrane 41 membrane assembly is arranged on the side of the seat bottom wall 3115 of the one-way valve 30 away from the valve cavity 313. Among them, the breathable membrane assembly 40 includes a breathable membrane 41, the breathable membrane 41 is connected to the seat bottom wall 3115, and the breathable membrane 41 covers the fourth through hole 3114. In this embodiment, the breathable membrane assembly 40 is compounded with the one-way valve 30, and the breathable membrane 41 is attached to the seat bottom wall 3115 of the one-way valve 30, which can reduce the installation height; at the same time, only the one-way valve 30 needs to be connected to the end cover 21, which can simplify the assembly process.

Please refer to Figures 20 and 21. Figure 20 is a schematic diagram of the exploded structure of the exhaust assembly according to one or more embodiments; Figure 21 is a schematic diagram of the cross-sectional structure of the exhaust assembly according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 is arranged on the side of the seat bottom wall 3115 of the one-way valve 30 away from the valve cavity 313, wherein the breathable membrane assembly 40 includes a breathable membrane 41 and a metal member 42, the metal member 42 is provided with a first breathable hole 491, the breathable membrane 41 is arranged on the metal member 42 and covers the first breathable hole 491, and the metal member 42 is connected to the seat bottom wall 3115. In this embodiment, by connecting the metal member 42 to the seat bottom wall 3115, the connection strength can be improved.

Please refer to Figures 22 and 23, Figure 22 is a schematic diagram of the exploded structure of the exhaust assembly according to one or more embodiments; Figure 23 is a schematic diagram of the cross-sectional structure of the exhaust assembly according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 is disposed on the side of the seat bottom wall 3115 facing the valve cavity 313.

The valve cavity 313 includes a first cavity 3131 and a second cavity 3132 which are connected. The second cavity 3132 is closer to the seat bottom wall 3115. In a direction parallel to the seat bottom wall 3115, the cross-sectional area of the first cavity 3131 is greater than the cross-sectional area of the second cavity 3132. The valve core 32 is located in the first cavity 3131, and the breathable membrane assembly 40 is located in the second cavity 3132. This arrangement allows the gas to enter the valve cavity and then pass through the breathable membrane assembly before reaching the valve core, thereby preventing the electrolyte from overflowing.

Further, the seat side wall 3116 includes a first side wall portion 3116a, a second side wall portion 3116b and a third side wall portion 3116c, the first side wall portion 3116a and the second side wall portion 3116b enclose a first cavity 3131, the third side wall portion 3116c and the seat bottom wall 3115 enclose the first cavity 3131, and the blocking member 321 of the valve core 32 abuts against the second side wall portion 3116b. In this embodiment, the second cavity 3132 is an open cavity to communicate with the first cavity 3131, and the blocking member 321 of the valve core 32 located in the first cavity 3131 abuts against the second side wall portion 3116b, and the second cavity 3132 can be blocked by the blocking member 321. When the internal air pressure of the battery cell is low, the gas cannot enter the first cavity 3131 from the second cavity 3132 . When the internal air pressure of the battery cell is high, the gas enters the second cavity 3132 , pushes open the sealing member 321 , enters the first cavity 3131 , and then is discharged from the gas outlet of the valve cavity 313 .

Please continue to refer to FIG. 23 . According to some embodiments of the present application, the breathable membrane assembly 40 is located in the second cavity 3132 , so that the gas passes through the breathable membrane assembly 40 first when being discharged from the first cavity 3131 through the second cavity 3132 .

Among them, the breathable membrane assembly 40 can only include a breathable membrane 41, which is attached to the side of the seat bottom wall 3115 facing the valve cavity 313 and covers the fourth through hole 3114. In this case, the gas entering from the fourth through hole 3114 passes through the breathable membrane 41, blocking the electrolyte from entering the second cavity 3132.

In another embodiment, the breathable membrane assembly 40 may include a breathable membrane 41 and a metal component 42. The breathable membrane 41 is disposed on the metal component 42. The metal component 42 is connected to the wall of the second cavity 3132 (the third side wall portion 3116c). This can improve the stability of the connection and prevent the breathable membrane 41 from being displaced by the gas.

The breathable membrane 41 can be arranged on the side of the metal part 42 facing the seat bottom wall 3115, so that the metal part 42 has a supporting force on the breathable membrane 41 to prevent the breathable membrane 41 from being displaced by the gas. In other embodiments, the breathable membrane 41 can also be arranged on the side of the metal part 42 away from the seat bottom wall 3115.

Please continue to refer to Figure 23. According to some embodiments of the present application, when the breathable membrane 41 is arranged on the side of the metal part 42 facing the seat bottom wall 3115, the surface of the side of the metal part 42 away from the breathable membrane 41 is lower than the surface of the second side wall portion 3116b. Through this arrangement, a certain cavity can be created between the metal part 42 and the sealing part 321, which is beneficial to the discharge of gas.

23, according to some embodiments of the present application, the battery cell 20 further includes a sealing ring 80, which is disposed between the breathable membrane assembly 40 and the seat bottom wall 3115. This arrangement can improve the sealing between the breathable membrane assembly 40 and the seat bottom wall 3115.

Further, the sealing ring 80 is arranged between the breathable membrane 41 and the seat bottom wall 3115, the sealing ring 80 is arranged around the fourth through hole 3114, the sealing ring 80 is provided with a second breathable hole 801, the aperture of the second breathable hole 801 is larger than the aperture of the fourth through hole 3114, and the breathable membrane 41 covers the second breathable hole 801. Through this arrangement, the sealing between the breathable membrane 41 and the seat bottom wall 3115 can be improved, and the sealing ring 80 will not block the flow of gas.

According to some embodiments of the present application, the metal member 42 is connected to the third side wall portion 3116c by welding; or the metal member 42 is interference fit with the third side wall portion 3116c.

According to some embodiments of the present application, the present application further provides a battery 100, which includes a battery cell 20 of any of the above schemes. Wherein, please refer to Figure 24, which is a schematic diagram of the exploded structure of the 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. Wherein, 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, 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, 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 can be in various shapes, such as a cylinder, a cuboid, etc.

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.

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.

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

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.

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.

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

Please refer to Figure 25, which is a schematic diagram of the structure of a vehicle according to one or more embodiments. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is arranged inside the vehicle 1000, and the battery 100 can be arranged at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and driving power requirements of the vehicle 1000.

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.

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 cell can be discharged to the outside of the shell in time, so that the air pressure inside the battery cell will not be too high, and the pressure relief mechanism will not open the valve prematurely, which can greatly improve the battery life. 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 cell, and one breathable membrane assembly is provided on the side of the end cover facing the outside of the battery cell. One breathable membrane assembly can be provided on the end cover, and the other breathable membrane assembly can be provided on the shell.

The above description is only an implementation method of the present application, and does not 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 used in other related technical fields, are also included in the patent protection scope of the present application.

Claims (21)

A battery cell, comprising: A housing having a wall portion and a receiving cavity; An exhaust component, disposed on the wall portion, and used to exhaust gas inside the housing; An electrolyte is filled in the containing cavity; Wherein, the conductivity of the electrolyte is: 2ms/cm≤conductivity≤16ms/cm; the exhaust rate of the exhaust component is: 0.6mL/day≤exhaust rate≤10.0mL/day. The battery cell according to claim 1, wherein: The conductivity of the electrolyte is: 8ms/cm≤conductivity≤16ms/cm; the exhaust rate of the exhaust component is: 3.3mL/day≤exhaust rate≤10.0mL/day; Optionally, the conductivity of the electrolyte is: 11 ms/cm≤conductivity≤14 ms/cm, and the exhaust rate of the exhaust component is 4.5 mL/day≤exhaust rate≤9.0 mL/day. The battery cell according to claim 1, wherein: The conductivity of the electrolyte is: 2ms/cm≤conductivity≤8ms/cm; the exhaust rate of the exhaust component is: 0.6mL/day≤exhaust rate≤5.0mL/day; Optionally, the conductivity of the electrolyte is: 4 ms/cm≤conductivity≤6 ms/cm; the exhaust rate of the exhaust component is 1.3 mL/day≤second exhaust rate≤3.9 mL/day. The battery cell according to any one of claims 1 to 3, wherein: The exhaust component comprises a breathable membrane component, the breathable membrane component comprises a breathable membrane, and the breathable membrane has a breathability rate of 3-10 mL/day. The battery cell according to claim 4, wherein: The breathable membrane comprises a first breathable membrane, and the breathability of the first breathable membrane is 3-4 mL/day; or The breathable membrane comprises a second breathable membrane, and the breathability of the second breathable membrane is 9-10 mL/day. The battery cell according to any one of claims 1 to 3, wherein: The exhaust component includes a one-way valve, and the opening pressure of the one-way valve is greater than or equal to 0.2 MPa; optionally, greater than or equal to 0.4 MPa; and further optionally, greater than or equal to 0.8 MPa. The battery cell according to any one of claims 1 to 3, wherein: The exhaust assembly includes a breathable membrane assembly and a one-way valve, the wall portion has a first exhaust hole, the first exhaust hole connects the inside of the shell with the outside of the shell, and the battery cell is configured so that the gas exhausted through the first exhaust hole flows through the one-way valve and the breathable membrane assembly. The battery cell according to claim 7, wherein: The opening pressure of the one-way valve is greater than or equal to 0.4 MPa, and the breathable membrane assembly includes a second breathable membrane, and the breathability rate of the second breathable membrane is 9-10 mL/day. The battery cell according to any one of claims 1 to 3, wherein: The exhaust assembly includes a breathable membrane assembly and a one-way valve, the wall portion has a first exhaust hole and a third exhaust hole arranged at intervals, the first exhaust hole and the third exhaust hole respectively connect the inside of the shell and the outside of the shell, and the battery cell is configured so that the gas exhausted through the first exhaust hole flows through the one-way valve, and the gas exhausted through the third exhaust hole passes through the breathable membrane assembly. The battery cell according to claim 9, wherein: The opening pressure of the one-way valve is greater than or equal to 0.8 MPa. The breathable membrane assembly includes a first breathable membrane. The breathability rate of the first breathable membrane is 3-4 mL/day. The battery cell according to any one of claims 1 to 10, wherein: The gas production rate of the battery cell is: 0.006 mL/Ah/D≤gas production rate≤0.066 mL/Ah/D; Optionally, the gas production rate of the battery cell is: 0.006 mL/Ah/D≤gas production rate≤0.033 mL/Ah/D; Optionally, the gas production rate of the battery cell is: 0.013 mL/Ah/D≤gas production rate≤0.026 mL/Ah/D; Optionally, the gas production rate of the battery cell is: 0.033 mL/Ah/D≤gas production rate≤0.066 mL/Ah/D; Optionally, the gas production rate of the battery cell is: 0.045 mL/Ah/D≤gas production rate≤0.060 mL/Ah/D. The battery cell according to any one of claims 1 to 11, wherein: The electrolyte includes one or more of chain ethers, ethylene glycol dimethyl ether and its derivatives, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and cyclic ethers. The battery cell according to any one of claims 1 to 12, wherein: The battery cell further includes an electrode assembly, which is accommodated in the accommodation cavity. The electrode assembly includes a positive electrode sheet and a negative electrode sheet, wherein: The positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer disposed on the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises 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; and/or The negative electrode plate includes a negative electrode current collector and a carbonaceous coating disposed on the negative electrode current collector, wherein the carbonaceous coating includes a carbonaceous material, and the carbonaceous material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes. The battery cell according to any one of claims 6 to 10, wherein: 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 channel of the valve cavity, and the valve core is configured to open the air inlet channel under the action of the gas inside the shell. The battery cell according to any one of claims 4, 5, 7-10, wherein: The breathable membrane assembly includes a breathable membrane and a connector, wherein the connector is provided with a first breathable hole, and the breathable membrane is provided on the connector and covers the first breathable hole; the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged. The battery cell according to claim 7 or 8, wherein: 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 wall portion is provided with a first exhaust hole, 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, and the one-way valve is at least partially accommodated in the first hole section. The battery cell according to claim 16, wherein: At least part of the valve body of the one-way valve protrudes from the outer surface; the wall portion has a first sinker that is recessed relative to the inner surface, the first sinker is arranged around the first exhaust hole, and the breathable membrane assembly is at least partly accommodated in the first sinker. The battery cell according to claim 16, wherein: At least part of the valve body of the one-way valve protrudes from the outer surface of the wall portion; the first exhaust hole also includes a second hole segment, along the thickness direction of the wall portion, the second hole segment is located between the through hole segment and the first hole segment, the aperture of the second hole segment is smaller than the aperture of the first hole segment, the aperture of the second hole segment is larger than the aperture of the through hole segment, the breathable membrane assembly is at least partially accommodated in the second hole segment, and the breathable membrane assembly is located on the side of the one-way valve facing the wall portion. The battery cell according to claim 16, wherein: The one-way valve comprises a valve body, at least part of which protrudes from the inner surface of the wall portion, the valve body comprises a valve seat and a valve cover, the valve seat comprises a seat bottom wall and a seat side wall connected to the seat bottom wall; the valve cover is arranged at one end of the valve seat away from the seat bottom wall, the valve cover, the seat side wall and the seat bottom wall are enclosed to form the valve cavity, and the valve seat is provided with an air inlet of the valve cavity; wherein, The breathable membrane assembly is arranged on a side of the seat bottom wall away from the valve cavity; or The air-permeable membrane assembly is arranged on a side of the seat bottom wall facing the valve cavity. A battery, comprising the battery cell according to any one of claims 1 to 19. An electrical device, comprising a battery cell as described in any one of claims 1 to 19, wherein the battery cell is used to provide electrical energy.