Battery cell, battery, and electric device

Abstract

The present application discloses a battery cell, a battery, and an electric device. The battery cell comprises a casing and a gas permeable membrane assembly; the casing has a wall part, the wall part is provided with a first exhaust hole, and the first exhaust hole makes the interior of the casing and the exterior of the casing communicated; the gas permeable membrane assembly is arranged on the wall part, the gas permeable membrane assembly comprises a gas permeable membrane, and the gas permeable membrane assembly covers the first exhaust hole. In the present application, on the basis of the arrangement, gas inside the battery cell in a sealed state can be discharged through the gas permeable membrane, and gas inside the battery casing is discharged out of the casing in time, thus preventing the air pressure in the battery casing from being too high, reducing the risk that a pressure relief mechanism opens a valve in advance, and greatly prolonging the service life of the battery.

Description

Battery cells, batteries and electrical equipment Technical Field

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

[0002] As global energy and environmental problems continue to intensify, new energy, as one of the areas of sustainable development, is developing rapidly. Batteries are being used more and more widely as a new energy source, and there are high requirements for their reliability and service life. During the charging and discharging process of the battery, the internal pressure of the battery will increase due to the generation of gas inside the battery. In order to ensure the safety of the battery cell, a pressure relief mechanism for releasing the internal pressure of the battery cell is generally provided on the outer shell of the battery cell, so that when the internal pressure or temperature of the battery cell reaches a threshold, the pressure relief mechanism can be actuated and release the pressure inside the battery cell. However, the pressure relief mechanism of the existing battery cell may actuate and release the pressure in advance during use, resulting in poor stability of the battery cell, which is not conducive to improving the service life and reliability of the battery cell. The above statements are only used to provide background technical information related to this application and do not necessarily constitute prior art.

[0003] Summary of the Invention

[0004] The main technical problem solved by the present application is to provide a battery cell, a battery and an electrical device, which can enable the battery cell to discharge internal gas through a breathable membrane in a sealed state, and promptly discharge the internal gas of the battery shell to the outside of the shell, so that the air pressure inside the battery shell will not be too high, reduce the risk of the pressure relief mechanism opening the valve prematurely, and significantly improve the life of the battery cell.

[0005] To address the above-mentioned technical issues, this application adopts a technical solution: providing a battery cell, comprising a housing and a breathable membrane assembly. The housing has a wall portion, which has a first vent, connecting the interior of the housing with the exterior. The breathable membrane assembly is disposed on the wall portion and includes a breathable membrane, which covers the first vent. This arrangement allows the battery cell to discharge internal gas through the breathable membrane while in a sealed state, promptly discharging the gas inside the battery housing to the exterior of the housing, preventing excessive pressure inside the housing and reducing the risk of premature valve opening of the pressure relief mechanism, significantly extending the life of the battery cell.

[0006] In one embodiment, the battery cell further includes a sealant disposed between the breathable membrane assembly and the wall portion. This arrangement can enhance the sealing between the breathable membrane assembly and the wall portion, thereby preventing external moisture, oxygen, etc. from entering the battery cell.

[0007] In one embodiment, the seal is disposed between the breathable membrane and the wall portion. This arrangement can achieve a seal between the breathable membrane and the wall portion, allowing gas to be discharged through the breathable membrane while also preventing external water vapor, oxygen, etc. from entering the battery cell.

[0008] In one embodiment, a sealant is disposed around the first vent hole and is provided with a second vent hole having a larger diameter than the first vent hole. The second vent hole is covered by a breathable membrane. This arrangement allows the sealant to confine gas passing through the first vent hole to the space enclosed by the sealant between the wall and the breathable membrane, allowing the gas to continue to be discharged through the breathable membrane. This also ensures a tight seal around the first vent hole, preventing external moisture from entering the battery cell through the first vent hole.

[0009] In one embodiment, the breathable membrane assembly further includes a connector having a first breathable hole, the breathable membrane being disposed on the connector to cover the first breathable hole, and the breathable membrane being disposed between the connector and the sealing member. With this arrangement, the sealing member can be fixed by the connector.

[0010] In one embodiment, the wall portion includes a first and second recessed platforms recessed relative to the wall surface. The first recessed platform is disposed around the second recessed platform, closer to the wall surface than the second recessed platform. The second recessed platform is disposed around the first vent. At least a portion of the seal is located on the second recessed platform, and at least a portion of the breathable membrane assembly is located on the first recessed platform. This arrangement reduces the installation height of the breathable membrane assembly and improves space utilization.

[0011] In one embodiment, the second sunken platform includes a platform surface, and a first boss protruding from the platform surface is further provided on the second sunken platform, and the first boss is spaced apart from the breathable membrane. This arrangement can reduce the risk of damage to the breathable membrane.

[0012] In one embodiment, the first boss is an annular boss surrounding the first exhaust hole. This arrangement can effectively position the seal and reduce installation difficulty.

[0013] In one embodiment, there are multiple first bosses, which are spaced apart in the circumferential direction of the first exhaust hole. This arrangement can simplify the manufacturing process while achieving positioning.

[0014] In one embodiment, the connecting piece is welded to the wall portion, which can enhance the connection stability between the breathable membrane assembly and the wall portion.

[0015] In one embodiment, the connecting member and the wall portion are interference-fitted, thereby simplifying the manufacturing process.

[0016] In one embodiment, the wall portion has a first recessed platform that is recessed relative to the wall portion surface. The first recessed platform is disposed around the first vent hole, and at least a portion of the breathable membrane assembly is located on the first recessed platform. This arrangement can reduce the installation depth of the breathable membrane assembly and improve space utilization.

[0017] In one embodiment, the wall portion includes an outer surface and an inner surface disposed opposite each other, with the outer surface facing the exterior of the housing and the inner surface facing the interior of the housing. The wall portion includes a first recessed platform that is recessed relative to the inner surface of the wall portion. This arrangement can reduce the installation height of the breathable membrane assembly and improve space utilization.

[0018] In one embodiment, the wall portion further includes a third recessed portion that is recessed relative to the inner surface of the wall portion. The first recessed portion is disposed around the third recessed portion, the first recessed portion being closer to the inner surface of the wall portion than the third recessed portion, and the third recessed portion being disposed around the first exhaust hole. This arrangement creates a cavity in the area where the third recessed portion is located, facilitating gas discharge.

[0019] In one embodiment, the breathable membrane assembly further includes a connector disposed on the first sink and provided with a first breathable hole; the breathable membrane is disposed on a side of the connector facing the interior of the housing, covering the first breathable hole; or the breathable membrane is disposed on a side of the connector facing the wall, covering the first breathable hole. This arrangement facilitates gas discharge.

[0020] In one embodiment, the orthographic projection of the first vent hole on the wall does not overlap with the area where the first exhaust hole is located. This arrangement can prevent foreign matter from entering the breathable membrane assembly through the first exhaust hole.

[0021] In one embodiment, the breathable membrane assembly is arranged on the side of the wall portion facing the interior of the housing. This arrangement is conducive to improving the sealing performance of the battery cell.

[0022] In one embodiment, the breathable membrane assembly is arranged on the side of the wall portion facing the outside of the shell. This arrangement facilitates the assembly of the breathable membrane assembly.

[0023] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite each other, with the outer surface facing the exterior of the housing and the inner surface facing the interior of the housing. The wall portion has a first recessed portion that is recessed relative to the outer surface, and the breathable membrane assembly is at least partially located within the first recessed portion. This arrangement can reduce the installation height of the breathable membrane assembly.

[0024] In one embodiment, the breathable membrane assembly further includes a connector disposed on the first sink and having a first air hole; and a breathable membrane disposed on a side of the connector facing the wall, the breathable membrane covering the first air hole. This arrangement facilitates gas discharge.

[0025] In one embodiment, the wall portion includes a wall body having an outer surface and an inner surface disposed opposite each other, with the outer surface facing the exterior of the housing and the inner surface facing the interior of the housing. The wall portion includes a wall boss that protrudes relative to the inner surface. The orthographic projection of the wall boss on the wall body at least partially overlaps with the orthographic projection of the breathable membrane assembly on the wall body. This arrangement enhances the strength of the wall portion in the area where the breathable membrane assembly is located.

[0026] In one embodiment, the battery cell further includes an insulating member disposed on the side of the wall portion facing the interior of the housing. A second vent hole is provided on the insulating member, extending through the insulating member and communicating with the first vent hole. This arrangement prevents contact between the wall portion and the electrode assembly, etc., reducing the risk of a short circuit.

[0027] In one embodiment, the insulating member is provided with a second boss protruding from the insulating member. The second boss is arranged around the second vent hole and extends toward the wall portion into the first vent hole. This arrangement protects the wall portion of the through hole from contact with the electrode assembly, etc., reducing the risk of short circuits.

[0028] In one embodiment, the second boss is spaced apart from the breathable membrane, thereby reducing the risk of damage to the breathable membrane assembly.

[0029] In one embodiment, the insulating member has an upper surface disposed toward the wall portion, the insulating member has a sixth recessed portion recessed relative to the upper surface, and the wall portion has a wall boss protruding relative to an inner surface of the wall portion, with the wall boss at least partially located on the sixth recessed portion. This arrangement can improve space utilization.

[0030] In one embodiment, the battery cell further includes an adapter plate having a first surface disposed toward the insulating member, the adapter plate having a seventh recessed portion recessed relative to the first surface, and the insulating member having a main body boss protruding relative to a lower surface of the insulating member, with the main body boss at least partially located on the seventh recessed portion. This arrangement can improve space utilization.

[0031] In one embodiment, the battery cell further includes a shielding member mounted on the wall portion, located on the side of the wall portion facing the exterior of the housing, and shielding the breathable membrane assembly. A first exhaust passage is formed between the shielding member and the wall portion, connecting the exhaust port of the breathable membrane assembly with the exterior of the battery cell. This arrangement protects the breathable membrane assembly and prevents dust and particles from entering the breathable membrane assembly.

[0032] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite each other, the outer surface facing the exterior of the housing, and the inner surface facing the interior of the housing. The wall portion has a fourth sunken platform that is recessed relative to the outer surface of the wall portion, the fourth sunken platform surrounding the first sunken platform and closer to the outer surface of the wall portion than the first sunken platform. The breathable membrane assembly is at least partially disposed on the first sunken platform, and the shielding member is at least partially disposed on the fourth sunken platform. This arrangement can reduce the installation height of the shielding member and the breathable membrane assembly.

[0033] In one embodiment, the wall further comprises a fifth recessed portion that is recessed relative to the outer surface of the wall, with the fourth recessed portion surrounding the fifth recessed portion, and the fifth recessed portion located between the fourth recessed portion and the first recessed portion. This arrangement creates a cavity between the breathable membrane assembly and the obstruction member, facilitating the controlled discharge of gas.

[0034] In one embodiment, the first exhaust channel includes a first exhaust gap formed between the shielding member and the side surface of the fourth sink, and the first exhaust gap is used to connect the gas outlet and the outside of the housing. This arrangement facilitates the exhaust of gas.

[0035] In one embodiment, the first exhaust channel further includes a second exhaust gap formed between the shielding member and the bottom surface of the fourth sink, the second exhaust gap communicating with the first exhaust gap and the gas outlet.

[0036] In one embodiment, the battery cell further includes a protective patch, which is disposed on a side of the wall portion facing the exterior of the housing and covers the shielding member. This arrangement protects the shielding member while maintaining the appearance of the battery cell.

[0037] In one embodiment, the protective patch is provided with an information collection hole that penetrates the protective patch, and the orthographic projection of the information collection hole on the wall is located within the shielding member. This allows the exposed area of ​​the information collection hole to be the surface of the shielding member, thereby enabling the shielding member to be provided with an information code or connected to a detection element for sampling.

[0038] In one embodiment, the battery cell further includes a protective patch disposed on the side of the wall facing the exterior of the housing, covering the first vent. This arrangement prevents dust and particles from the external environment from entering the first vent, reducing the risk of blocked exhaust passages and resulting in poor ventilation.

[0039] In one embodiment, an adhesive layer is provided on the side of the protective patch facing the wall, bonding the protective patch to the wall. The adhesive layer is provided with an escape groove, forming a second exhaust channel between the escape groove and the wall. This arrangement enhances the connection strength between the protective patch and the wall while leaving space for exhaust.

[0040] In one embodiment, the breathable membrane assembly further includes a connector having a first breathable hole, and the breathable membrane is disposed on the connector, covering the first breathable hole. This can enhance the connection strength between the breathable membrane assembly and the wall while reducing the probability of deformation of the breathable membrane.

[0041] In one embodiment, the connector has a first annular platform that is recessed relative to the connector surface. The first annular platform is disposed around the first vent hole, and the breathable membrane is disposed on the first annular platform. This arrangement can reduce the overall height of the breathable membrane assembly.

[0042] In one embodiment, the breathable membrane assembly further includes a backing member disposed between the breathable membrane and the connector, wherein the backing member has a higher air permeability than the breathable membrane. This arrangement provides support for the breathable membrane and protects the breathable membrane from significant deformation.

[0043] In one embodiment, the connector further comprises a second annular platform recessed relative to the surface of the connector, the second annular platform surrounding the first vent hole, and the backing member is at least partially disposed on the second annular platform, thereby reducing the overall height of the breathable membrane assembly.

[0044] In one embodiment, the area of ​​the groove where the second annular table is located is 30mm 2 -250mm 2 Optionally, the area of ​​the groove where the second annular table is located is 60mm 2 -200mm 2 This can improve the air permeability of the controlled breathable membrane assembly and reduce the amount of external water vapor entering the battery cell.

[0045] In one embodiment, the first ventilation holes include a plurality of circular through holes, each having a diameter less than 3.0 mm, which can provide support for the breathable membrane and protect the breathable membrane from significant deformation.

[0046] In one embodiment, the thickness of the breathable membrane is 0.1-3.0 mm, and optionally, 0.2-0.8 mm, so as to balance the breathability and strength of the breathable membrane.

[0047] In one embodiment, the connecting piece is a metal piece, which can enhance the connection strength between the breathable membrane assembly and the wall.

[0048] In one embodiment, the permeability rate of the breathable membrane is 3-10 mL / day, and optionally, 4-6 mL / day, so as to timely discharge gas from the battery cells and maintain the internal pressure balance of the battery.

[0049] In one embodiment, the housing includes a shell and an end cap. The shell defines an opening within the housing for accommodating the electrode assembly. The end cap seals the opening. The end cap is a wall, or the shell includes the wall, or the wall is located at the top of the housing when the battery cell is in a placed state. This facilitates the timely discharge of gas.

[0050] In one embodiment, the battery cell further includes a pressure relief mechanism, the pressure relief structure being disposed on the housing, and the pressure relief mechanism being configured to be activated and release internal pressure of the battery cell when the battery cell experiences thermal runaway.

[0051] To solve the above technical problems, another technical solution adopted by the present application is to provide a battery comprising the above battery cells, which has at least the same advantages as the battery cells.

[0052] To solve the above technical problems, another technical solution adopted by the present application is to provide an electrical device comprising the above battery, which has at least the same advantages as the battery.

[0053] 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

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0055] FIG1 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0056] FIG2 is a schematic diagram of a partially exploded structure of a battery cell according to one or more embodiments;

[0057] FIG3 is a schematic cross-sectional view of a breathable membrane assembly according to one or more embodiments;

[0058] FIG4 is a schematic cross-sectional view of a breathable membrane assembly according to one or more embodiments;

[0059] FIG5 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0060] FIG6 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0061] FIG7 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0062] FIG8 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0063] FIG9 is a schematic diagram of a partially exploded structure of a battery cell according to one or more embodiments;

[0064] FIG10 is an enlarged schematic diagram of area A in FIG9 ;

[0065] FIG11 is a schematic diagram of a partial cross-sectional structure of an end cap according to one or more embodiments;

[0066] FIG12 is a schematic diagram of a partially exploded structure of a battery cell according to one or more embodiments;

[0067] FIG13 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0068] FIG14 is a schematic diagram of a partially exploded structure of a battery cell according to one or more embodiments;

[0069] FIG15 is a schematic diagram of a partial cross-sectional structure of an insulating member according to one or more embodiments;

[0070] FIG16 a is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0071] FIG16 b is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments.

[0072] FIG17 a is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0073] FIG17 b is a bottom view of an adhesive layer of a protective patch according to one or more embodiments;

[0074] FIG18 is a schematic diagram of an exploded structure of a battery according to one or more embodiments;

[0075] FIG19 is a schematic structural diagram of a vehicle according to one or more embodiments.

[0076] In the figure: 1000, vehicle; 300, motor; 200, controller; 100, battery; 10, housing; 11, first portion; 12, second portion; 20, battery cell; 21, end cap; 21a, outer surface; 21b, inner surface; 211, first boss; 212, wall boss; 291, first vent; 22, housing; 23, electrode assembly; 24, insulator; 241, second boss; 242, Main body; 242a, upper surface; 2421, main body boss; 292, second vent; 25, electrode terminal; 26, adapter; 26a, first surface; 40, breathable membrane assembly; 41, breathable membrane; 42, metal part; 491, first vent; 43, backing member; 44, sealing member; 492, second vent; 50, shielding member; 501, first vent gap; 60, protective patch; 601, Information collection hole; 602, first avoidance hole; 603, second avoidance hole; 610, bonding layer; 611, avoidance groove; 70, pressure relief mechanism; T1, first annular table; T2, second annular table; T3, transition surface; S1, first sinking platform; S11, bearing surface; S12, connection surface; S2, second sinking platform; S22, platform surface; C1, first transition connection surface; S3, third sinking platform; C2, second transition connection surface; S4, fourth sinking platform; S42, connection surface; S5, fifth sinking platform; C3, third transition connection surface; C4, fourth transition connection surface; S6, sixth sinking platform; S7, seventh sinking platform; W1, weld. DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solution and effect of this application clearer and more specific, the following embodiments of the technical solution of this application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0079] In the description of the embodiments of the present application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood as indicating or implying relative importance or implicitly indicating the quantity, 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), similarly, "multiple groups" refers to more than two (including two), and "multiple pieces" refers to more than two (including two), unless otherwise clearly and specifically defined.

[0080] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0081] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0082] Amounts, ratios, and other numerical values ​​are presented herein in a range format. It should be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include not only the values ​​explicitly specified as limits of the range, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0083] In the description of the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and do not constitute any limitation on this application.

[0084] 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., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0085] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0086] Batteries have a wide range of applications in the new energy sector, primarily in electric vehicles, energy storage systems, and renewable energy. In the electric vehicle sector, higher performance features such as longer driving range and faster charging are gradually being achieved. In energy storage systems, batteries are widely used for large-scale and distributed energy storage. They can balance grid loads, store renewable energy such as solar and wind power, and release the stored energy during peak periods. Furthermore, small rechargeable batteries are widely used in applications such as wearable devices, drones, and smart homes.

[0087] As the battery charges and discharges, some side reactions generate gases. If these gases are not promptly discharged, the internal pressure of the battery will increase. Excessive internal pressure can negatively impact the battery's performance and appearance. For example, in severe cases, this can have devastating effects on the battery's performance and appearance, such as leakage, bulging, increased internal resistance, and shortened discharge time and cycle life. Furthermore, batteries can be subject to abnormal operation during use, including overcharging, over-discharging, and internal failures. In these cases, the chemical reactions within the battery may become uncontrolled, accompanied by a violent release of gas, and even trigger thermal runaway. Battery thermal runaway refers to a chain reaction phenomenon triggered by various factors. The large amount of heat and harmful gases emitted by thermal runaway can cause the battery to catch fire and explode.

[0088] To ensure the safety of battery cells, a pressure relief mechanism is typically installed on the outer shell of the battery cell to release the internal pressure of the battery cell, thereby effectively improving the safety of the battery cell. However, during the use of the battery cell, unstable internal pressure may cause the pressure relief mechanism of the battery cell to activate prematurely, resulting in poor stability in the use of the battery cell, which is not conducive to improving the service life and reliability of the battery cell.

[0089] Based on the above considerations, an embodiment of the present application provides a battery cell, on which a breathable membrane assembly is provided. The permeability of the breathable membrane in the breathable membrane assembly is utilized to timely discharge the gas inside the battery cell and maintain a stable internal pressure of the battery cell.

[0090] Please refer to Figure 1, which is a schematic diagram of the exploded structure of a battery cell 20 according to one or more embodiments. A battery cell 20 is the smallest unit that makes up a battery 100. As shown in Figure 1, a battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0091] The end cap 21 refers to a component that covers the opening of the housing 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 housing 22 to match the housing 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the end cap 21 is less likely to deform when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved safety performance. Functional components such as electrode terminals 25 can be provided on the end cap 21. The electrode terminals 25 can be used to electrically connect to the electrode assembly 23 to output or input electrical energy from the battery cell 20. Exemplarily, the battery cell 20 is provided with two electrode terminals 25, and both electrode terminals 25 are mounted on the end cap 21. The two electrode terminals 25 are respectively used to electrically connect to the two tabs of opposite polarity of the electrode assembly 23 to respectively output or input the positive and negative electrodes of the battery cell 20. 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. 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 24 may be plastic, rubber, etc.

[0092] The housing 22 is a component that cooperates with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and end cap 21 can be separate components. An opening can be provided in the housing 22, and the end cap 21 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and housing 22 can be integrated. Specifically, the end cap 21 and housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be enclosed, the end cap 21 is placed over the housing 22. The housing 22 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, or a hexagonal prism. Specifically, the shape of the housing 22 can be determined based on the specific shape and size of the electrode assembly 23. The housing 22 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0093] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 22. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 23, and the parts of the positive and negative electrode sheets without active materials each constitute a tab. The positive and negative electrode tabs 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 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode terminals 25 to form a current loop.

[0094] According to some embodiments of the present application, the present application discloses a battery cell 20, which includes an outer shell and a breathable membrane assembly 40. The outer shell has a wall portion, and the wall portion has a first exhaust hole, which connects the inside of the outer shell with the outside of the outer shell; the breathable membrane assembly 40 is arranged on the wall portion, and the breathable membrane assembly 40 includes a breathable membrane 41, and the breathable membrane assembly 40 covers the first exhaust hole.

[0095] The housing includes an end cap 21 and a shell 22. The wall portion can be either the end cap 21 or the wall of the shell 22. In other words, the breathable membrane assembly 40 can be disposed on either the end cap 21 or the shell 22. The following description of this application will use the example of the wall portion being the wall of the end cap 21, but this should not limit this application.

[0096] Please refer to Figure 2, which is a schematic diagram of a partially exploded structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 includes an end cap 21 and a breathable membrane assembly 40. The end cap 21 is provided with a first vent 291. The breathable membrane assembly 40 is disposed on the end cap 21 and covers the first vent 291. The first vent 291 connects the interior of the housing with the exterior of the housing. Gas inside the battery cell 20 housing can be discharged through the first vent 291 to regulate the pressure inside the battery cell 20 housing. The first vent can be located anywhere on the end cap 21, and can be one or more. The aperture of the first vent can be set as needed. The size and number of the vents can be designed based on the capacity of the battery cell 20, the type and volume of the battery 100, the gas production volume, the gas production rate, and other factors. As mentioned above, the first vent can also be located on any wall of the housing 22.

[0097] The breathable membrane assembly 40 includes a breathable membrane 41, which is made of a breathable material with excellent air permeability, allowing gas molecules to pass through. By installing the breathable membrane assembly 40 on the end cap 21 and covering the first vent 291 with the breathable membrane 41, the battery cell 20 can release internal gas through the breathable membrane 41 while in a sealed state. This allows the gas inside the battery 100 housing to be promptly discharged outside the housing, preventing excessive pressure inside the battery 100 housing. This reduces the risk of premature valve opening of the pressure relief mechanism 70, significantly extending the life of the battery 100.

[0098] In some embodiments, the breathable membrane 41 also has a liquid barrier property, blocking the passage of liquid, so that it can prevent the overflow of the electrolyte while discharging the gas. In addition, the breathable membrane 41 can also block external water vapor, dust and impurities from entering the interior of the battery cell 20 through the first exhaust hole 291, protect the internal environment of the battery cell 20, and effectively improve the reliability of the battery cell 20. The breathable membrane 41 also has good weather resistance, chemical corrosion resistance, and structural stability. If it is an automotive power battery 100, it also needs to have oleophobicity. Therefore, the material of the breathable membrane 41 can be selected from polymer materials, such as polytetrafluoroethylene, polypropylene, polyethylene, polyurethane, etc. In addition, since the generation of gas inside the battery 100 will cause the internal pressure to rise rapidly, the breathable membrane 41 needs to have certain mechanical strength and elasticity.

[0099] Please refer to Figure 3, which is a schematic cross-sectional view of a breathable membrane assembly 40 according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 further includes a connector 42. That is, the breathable membrane assembly 40 includes a breathable membrane 41 and a connector 42, and the connector 42 is used to support the breathable membrane 41. Specifically, the connector 42 is provided with a first vent 491, and the breathable membrane 41 is disposed on the connector 42, and the breathable membrane 41 covers the first vent 491. The breathable membrane 41 is configured to allow gas inside the battery cell 20 to pass through the breathable membrane 41 and be discharged.

[0100] The connector 42 can support the breathable membrane 41 and reduce the risk of excessive deformation of the breathable membrane 41. At the same time, the connector 42 can also serve as a medium for connecting the breathable membrane assembly 40 and the end cap 21. The breathable membrane 41 is connected to the end cap 21 through the connector 42 to improve the stability of the connection. The connector 42 is provided with at least one first air hole 491, which serves as a release channel for the gas inside the battery 100 so that the gas can pass through the connector 42. The shape of the first air hole 491 includes geometric shapes such as circle, square, and ellipse. The connector 42 can also be provided with multiple first air holes 491. The aperture, shape, and arrangement of the first air holes 491 are not specifically limited here. Optionally, the aperture of the first air hole 491 can be less than or equal to the aperture of the first exhaust hole 291.

[0101] In one embodiment, the first ventilation hole 491 includes one hole.

[0102] In one embodiment, the first ventilation hole 491 includes a plurality of circular through holes, and the diameter of each circular through hole is less than 3.0 mm.

[0103] In one embodiment, the connector 42 may be a metal member 42, a resin member, or the like. The metal member 42 may be made of copper, iron, aluminum, steel, or an aluminum alloy. The connector 42 may be a sheet-like structure. Selecting a metal member 42 facilitates welding the connector to the wall. The following description of this application utilizes an example in which the connector 42 may be a metal member 42. However, this is not intended to limit this embodiment and should not restrict this application. The present invention is also applicable to connectors made of non-metallic materials.

[0104] As shown in FIG3( a ), the breathable membrane 41 can be directly disposed on the surface of the metal member 42 . In other embodiments, a sink can also be disposed on the metal member 42 .

[0105] Continuing with Figure 3(b), according to some embodiments of the present application, the metal member 42 has a first annular platform T1 that is recessed relative to the surface of the metal member 42. The first annular platform T1 surrounds the first vent 491, and the breathable membrane 41 is disposed on the first annular platform T1. This arrangement reduces the installation height of the breathable membrane assembly 40.

[0106] Please refer to Figure 4, which is a schematic cross-sectional view of a breathable membrane assembly 40 according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 further includes a backing member 43, which is disposed between the breathable membrane 41 and the connector. The backing member 43 has a higher air permeability than the breathable membrane 41.

[0107] Among them, the breathable membrane assembly 40 includes a breathable membrane 41, a metal part 42 and a backing part 43. The breathable membrane 41 is arranged on the metal part 42, and the backing part 43 is arranged between the breathable membrane 41 and the metal part 42. The backing part 43 is used to support the breathable membrane 41 and allow the gas to pass through the breathable membrane 41.

[0108] 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, that is, the air permeability rate of the backing member 43 is greater than the air permeability rate of the breathable membrane 41. This is to not affect the air permeability process 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, polytetrafluoroethylene 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.

[0109] As shown in Figure 4(a), the metal component 42 also has a second annular surface T2 recessed relative to the surface of the metal component 42. This second annular surface T2 surrounds the first air vent 491, and the backing member 43 is mounted on this second annular surface T2. The second annular surface T2 supports the backing member 43, while the breathable membrane 41 can be directly attached to the surface of the metal component 42. In this configuration, due to the relatively small thickness of the breathable membrane 41, the overall height of the breathable membrane assembly 40 is relatively minimal. By reducing the number of recessed surfaces on the metal component 42, the manufacturing process is simplified while also improving the strength of the metal component 42.

[0110] In some embodiments, the area of ​​the groove where the second annular mesa T2 resides is 30 mm² to 250 mm². Optionally, the area of ​​the groove where the second annular mesa T2 resides is 60 mm² to 200 mm². For example, the area can be 30 mm², 50 mm², 80 mm², 100 mm², 120 mm², 150 mm², 180 mm², 200 mm², 230 mm², 250 mm², etc. This allows for accommodating backing members 43 of varying sizes. Furthermore, controlling the area of ​​the groove where the second annular mesa T2 resides within the aforementioned range can improve the permeability of the breathable membrane assembly 40 while reducing the amount of external moisture that enters the battery cell 20.

[0111] As shown in (b) of Figure 4, 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, as well as 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 breathable membrane 41 is arranged on the first annular table T1.

[0112] The first annular table surface T1 and the second annular table surface T2 are formed by inward depressions on the surface of the metal member 42. This can be achieved by stamping the metal member 42 to form the inward depressions, or by etching the metal member 42 to remove a portion of the structure. The depth of the depressions of the first annular table surface T1 and the second annular table surface T2 relative to the surface of the metal member 42 can be set based on the thickness of the breathable membrane 41 and the backing member 43. Preferably, the depth of the depression 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 surface T2 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.

[0113] In some embodiments, 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 .

[0114] By providing a recessed platform on the metal member 42 , the surface of the breathable membrane 41 can be flush with the surface of the metal member 42 , thereby reducing the overall height of the breathable membrane assembly 40 and further reducing the installation height of the breathable membrane assembly 40 on the end cover 21 .

[0115] In one embodiment, the breathable membrane 41 and the metal part 42 are compositely connected, for example, the breathable membrane 41 and the metal part 42 can be connected by using a nano injection molding process. Nano injection molding refers to nano molding technology (NMT, i.e., Nano Molding Technology), which is a process of combining metal and plastic using nanotechnology. That is, the metal surface is first nano-treated, and then the plastic is directly injection-molded on the metal surface, so that the metal and plastic can be integrally formed and finally combined into a product. The "nano" referred to here refers to a microporation process, that is, the metal surface is subjected to nano-level microporation treatment through a specific solution. The main purpose is to better combine the metal surface with the plastic and improve the connection strength.

[0116] According to some embodiments of the present application, the breathable membrane assembly 40 may include only a breathable membrane 41, and the breathable membrane 41 is directly compounded with the end cap 21, that is, the breathable membrane assembly 40 is provided on the end cap 21, and the breathable membrane 41 is connected to the end cap 21 and covers the first exhaust hole 291. As mentioned above, the end cap 21 may be nano-processed, and then the breathable membrane 41 is compounded and connected to the end cap 21. In this embodiment, by providing the breathable membrane 41, the gas inside the battery 100 can be discharged in a sealed state in a timely manner, and the electrolyte can be prevented from overflowing and the entry of external water vapor, thereby protecting the internal environment of the battery cell 20 and effectively improving the reliability of the battery 100. At the same time, the breathable membrane assembly 40 has only one layer of breathable membrane 41, which is relatively thin and has little effect on the installation height of the battery cell 20.

[0117] According to some embodiments of the present application, the breathable membrane 41 may be attached to the side of the end cap 21 facing the interior of the housing, or to the side of the end cap 21 facing the exterior of the housing. The breathable membrane 41 may be directly attached to the surface of the end cap 21, or a recessed platform may be provided on the end cap 21 to accommodate the breathable membrane 41, so that the surface of the breathable membrane 41 is flush with the surface of the end cap 21.

[0118] According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41 and a metal member 42. The breathable membrane 41 is disposed on the metal member 42. The breathable membrane assembly 40 is disposed on the end cap 21, and the metal member 42 is connected to the end cap 21. That is, the breathable membrane 41 is connected to the end cap 21 through the metal member 42.

[0119] In some embodiments, the metal member 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.

[0120] Please refer to Figures 5 and 6. Figure 5 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments, and Figure 6 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the end cap 21 has a first recessed portion S1 that is recessed relative to the surface of the end cap 21. The first recessed portion S1 is disposed around the first vent 291, and at least a portion of the breathable membrane assembly 40 is disposed on the first recessed portion S1.

[0121] The end cap 21 includes an outer surface 21a and an inner surface 21b disposed opposite each other, with the outer surface 21a facing the exterior of the housing and the inner surface 21b facing the interior of the housing. The breathable membrane assembly 40 can be disposed on the side of the end cap 21 facing the interior of the housing or on the side of the end cap 21 facing the exterior of the housing.

[0122] As shown in Figures 5(a) and (b), the breathable membrane assembly 40 is disposed on the side of the end cap 21 facing the interior of the housing. The wall portion has an outer surface 21a and an inner surface 21b disposed opposite each other, with the outer surface 21a facing the exterior of the housing and the inner surface 21b facing the interior of the housing. The wall portion has a first recessed platform that is recessed relative to the inner surface 21b of the wall portion.

[0123] Specifically, the first sinking platform S1 is recessed relative to the inner surface 21b of the end cover 21, and the breathable membrane assembly 40 is disposed on the first sinking platform S1. Optionally, the breathable membrane assembly 40 can be connected to the end cover 21 via a metal member 42.

[0124] 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 can be stamped to form the recessed first depression S1, or the end cover 21 can be etched to remove part of the structure to form the recessed first depression S1. The recessed 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 depth of the first recessed portion S1 relative to the inner surface 21b of the end cap 21 is equal to the thickness of the breathable membrane assembly 40, so that the breathable membrane assembly 40 is accommodated within the first recessed portion S1, and the surface of the breathable membrane assembly 40 facing the interior of the housing is flush with the inner surface 21b of the end cap 21. In this way, the installation height of the breathable membrane assembly 40 can be reduced, thereby reducing the space occupied by the battery cell 20 interior housing and improving the space utilization inside the housing.

[0125] As shown in Figure 5(a), the breathable membrane 41 can be positioned on the side of the metal member 42 facing the interior of the housing; this arrangement reduces the impact of the operating environment of the battery cell 20 on the breathable membrane 41. As shown in Figure 5(b), the breathable membrane 41 can also be positioned on the side of the metal member 42 facing the end cap 21, that is, between the metal member 42 and the end cap 21; this arrangement reduces erosion of the breathable membrane 41 by the electrolyte system.

[0126] As shown in Figure 6, the breathable membrane assembly 40 is disposed on the side of the end cap 21 facing the exterior of the housing. Specifically, a first recessed portion S1 is recessed relative to the outer surface 21a of the end cap 21. The breathable membrane assembly 40 is disposed on the first recessed portion S1 and connected to the end cap 21 via a metal member 42. In this embodiment, the first recessed portion S1 is formed by recessing the outer surface 21a of the end cap 21 toward the inner surface 21b of the end cap 21. Similarly, the depth of the recessed portion S1 relative to the outer surface 21a of the end cap 21 can be equal to the thickness of the breathable membrane assembly 40.

[0127] As shown in Figure 6 , the breathable membrane 41 is disposed on the side of the metal member 42 facing the interior of the housing, that is, between the end cap 21 and the metal member 42. This arrangement reduces the impact of the operating environment of the battery cell 20 on the breathable membrane 41. In other embodiments, the breathable membrane 41 can also be disposed on the side of the metal member 42 facing the exterior of the housing.

[0128] Please refer to Figure 7, which is a partial cross-sectional view of a battery cell 20 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 end cap 21 facing the interior of the housing, and the breathable membrane 41 is disposed on the side of the metal member 42 facing the interior of the housing.

[0129] In some embodiments, the wall also has a third sinker S3 that is recessed relative to the inner surface 21b of the wall, the first sinker S1 is arranged around the third sinker S3, the first sinker S1 is closer to the inner surface 21b than the third sinker S3, and the third sinker S3 is arranged around the first exhaust hole 491.

[0130] Among them, the end cover 21 has a first sinker S1, a third sinker S3 and a second transition connection surface C2 that are recessed relative to the inner surface 21b of the end cover 21. The first sinker S1 is arranged around the third sinker S3, and the second transition connection surface C2 connects the first sinker S1 and the third sinker S3. The first sinker S1 is closer to the inner surface 21b of the end cover 21 than the third sinker S3. The third sinker S3 is arranged around the first exhaust hole 291. The breathable membrane assembly 40 is located on the first sinker S1, and the breathable membrane 41 is arranged on the side of the metal part 42 facing the inside of the shell.

[0131] Specifically, the first sinker S1 and the third sinker S3 are formed by the inner surface 21b of the end cover 21 being recessed toward the outer surface 21a of the end cover 21. The purpose of setting the first sinker S1 is to carry and accommodate the breathable membrane assembly 40, and the depth of the recess relative to the inner surface 21b of the end cover 21 can be set according to the thickness of the breathable membrane assembly 40 so as to accommodate the breathable membrane assembly 40. The purpose of setting the third sinker S3 is to form a certain cavity between the breathable membrane assembly 40 and the end cover 21 so that the gas can be discharged smoothly. The depth of the recess of the third sinker S3 relative to the first sinker S1 (i.e., the height of the second transition connection surface C2) is set according to demand.

[0132] Referring to FIG. 7 , according to some embodiments of the present application, the orthographic projection of the first ventilation hole 491 on the end cover 21 does not overlap with the area where the first exhaust hole 291 is located.

[0133] As shown in FIG7 , the first exhaust hole 291 and the first air hole 491 are not arranged correspondingly, which is beneficial to regulating the discharge of gas on the one hand; on the other hand, it reduces the risk of external medium entering the first air hole 491 and affecting the normal operation of the air permeable membrane 41 .

[0134] 5 and 6 , the metal member 42 can be connected to the end cap 21 by welding. The first sink S1 includes a bearing surface S11 parallel to the surface of the end cap 21 , and the bearing surface S11 is used to bear the breathable membrane assembly 40 .

[0135] Continuing with Figures 5 and 6 , the metal member 42 can be connected to the end cap 21 by welding. The first sink S1 includes a connecting surface S12 perpendicular to the bearing surface S11. The metal member 42 is a metal sheet of a certain thickness that can be connected to the end cap 21 using the side of the metal sheet. Specifically, the side of the metal sheet can be welded to the connecting surface S12 of the first sink S1, and assembly can be achieved by laser welding. The position W1 shown in Figures 5 and 6 is the welding location between the two.

[0136] Please refer to Figure 8, which is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes a seal 44, which is disposed between the breathable membrane assembly 40 and the end cap 21. The provision of the seal 44 maintains a seal between the breathable membrane assembly 40 and the end cap 21.

[0137] The interface between the breathable membrane 41 and the metal member 42 is formed by two structures with significantly different properties, and its sealing performance has certain limitations. In particular, as gas is continuously discharged, the interface between the breathable membrane 41 and the metal member 42 is prone to failure, resulting in a deterioration in sealing performance. This allows gas to be discharged through the interface between the breathable membrane 41 and the metal member 42, and also easily allows external water vapor to enter the interior of the battery 100 along this path. In some embodiments, the metal member 42 is connected to the end cap 21 by welding. The sealing performance of the weld interface is limited by the precision of the welding process and is also prone to deterioration in sealing performance. By providing a seal 44 between the breathable membrane assembly 40 and the end cap 21, two sealing interfaces are sealed: the seal between the lower surface of the seal 44 and the end cap 21, and the seal between the upper surface 242a of the seal 44 and the breathable membrane assembly 40. This can reduce the sealing requirements for the interface between the breathable membrane 41 and the metal member 42 and the weld W1, and can also reduce the process precision, thereby reducing manufacturing costs.

[0138] 8 and 9 , FIG9 is a partial exploded structural diagram of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, a seal 44 is disposed between the breathable membrane 41 and the wall.

[0139] The seal 44 is disposed between the breathable membrane 41 and the end cap 21 to achieve a seal between the breathable membrane 41 and the end cap 21, allowing gases to be discharged through the breathable membrane 41 without leaking to other areas. It also prevents external moisture, oxygen, etc. from entering the battery 100.

[0140] In some embodiments, a seal 44 is disposed around the first vent 291. The seal 44 is provided with a second vent 492. The aperture of the second vent 492 is larger than that of the first vent 291. The breathable membrane 41 covers the second vent 492. By disposing the seal 44 around the first vent 291, the seal 44 can be used to confine the gas passing through the first vent 291 to the space enclosed by the seal 44 between the end cap 21 and the breathable membrane 41, so that the gas can continue to be discharged only after passing through the breathable membrane 41. In other words, the seal 44 is an annular sealing ring that is disposed around the first vent 291. This arrangement can also achieve sealing around the first vent 291, preventing external moisture from entering the interior of the battery 100 through the first vent 291.

[0141] 8 and 9 , the breathable membrane assembly 40 further includes a connector 42 , which is provided with a first breathable hole 491 , a breathable membrane 41 disposed on the connector 42 , the breathable membrane 41 covering the first breathable hole 491 , and the breathable membrane 41 disposed between the connector 42 and the sealing member 44 .

[0142] For example, if the connector 42 is a metal member 42, the seal 44 is disposed between the metal member 42 and the end cap 21, and the breathable membrane 41 is disposed between the metal member 42 and the seal 44. That is, in terms of stacking, the seal 44 is stacked on the end cap 21, the breathable membrane 41 is stacked on the seal 44, and the metal member 42 is stacked on the breathable membrane 41. In this manner, the connection between the metal member 42 and the end cap 21 can be used to secure the seal 44, thereby achieving a seal between the seal 44 and the end cap 21, and between the seal 44 and the breathable membrane 41. In other words, the metal member 42 can be used to press the seal 44 onto the end cap 21, and the pressing force can be used to bond the seal 44 to the end cap 21 and the breathable membrane 41, forming a sealed interface. The sealing member 44 shown in FIG. 8 is pressed between the breathable membrane 41 and the end cap 21 . In other embodiments, the setting position of the sealing member 44 can be moved to the left or right and directly pressed between the metal member 42 and the end cap 21 .

[0143] Please refer to Figures 8, 9, 10 and 11, Figure 10 is an enlarged schematic diagram of the area A in Figure 9, and Figure 11 is a schematic diagram of a partial cross-sectional structure of the end cover 21 according to one or more embodiments. According to some embodiments of the present application,

[0144] The end cover 21 has a first sinker S1 and a second sinker S2 that are recessed relative to the surface of the end cover 21. The first sinker S1 is arranged around the second sinker S2. The first sinker S1 is closer to the surface of the end cover 21 than the second sinker S2. The second sinker S2 is arranged around the first exhaust hole 291. The seal 44 is located on the second sinker S2, and the breathable membrane assembly 40 is located on the first sinker S1.

[0145] Among them, the end cover 21 has a first sinker S1, a second sinker S2 and a first transition connection surface C1 that are recessed relative to the surface of the end cover 21. The first sinker S1 is arranged around the second sinker S2. The first transition connection surface C1 connects the first sinker S1 and the second sinker S2. The first sinker S1 is closer to the surface of the end cover 21 than the second sinker S2. The second sinker S2 is arranged around the first exhaust hole 291. The seal 44 is located on the second sinker S2, and the breathable membrane assembly 40 is located on the first sinker S1.

[0146] As previously mentioned, the end cap 21 includes an outer surface 21a and an inner surface 21b disposed opposite each other, with the outer surface 21a facing the exterior of the housing and the inner surface 21b facing the interior of the housing. The breathable membrane assembly 40 can be disposed on the side of the end cap 21 facing the interior of the housing or on the side of the end cap 21 facing the exterior of the housing.

[0147] As shown in FIG8( a ), the breathable membrane assembly 40 is disposed on a side of the end cap 21 facing the outside of the housing.

[0148] The end cover 21 has a first depression S1 that is recessed relative to the outer surface 21 a , and the breathable membrane assembly 40 is at least partially located in the first depression S1 .

[0149] The above solution can reduce the installation height of the breathable membrane assembly 40.

[0150] In some examples, the first sink S1 and the second sink S2 are recessed relative to the outer surface 21a of the end cover 21, that is, the first sink S1 and the second sink S2 are recessed from the outer surface 21a of the end cover 21 toward the inner surface 21b of the end cover 21. Similarly, the recess depth of the first sink S1 relative to the outer surface 21a of the end cover 21 can be equal to the thickness of the breathable membrane assembly 40. As shown in (b) of Figure 8, the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the inside of the shell. Specifically, the first sink S1 and the second sink S2 are recessed relative to the inner surface 21b of the end cover 21, that is, the first sink S1 and the second sink S2 are recessed from the inner surface 21b of the end cover 21 toward the outer surface 21a of the end cover 21.

[0151] According to some embodiments of the present application, as shown in (a) and (b) of FIG. 8 , the breathable membrane assembly 40 is located on the first sinking platform S1 , and the sealing member 44 is located on the second sinking platform S2 .

[0152] The depth of the first sink S1 relative to the surface of the end cap 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 of 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 depth of the first sink S1 relative to the surface of the end cap 21 is equal to the thickness of the breathable membrane assembly 40, so that the breathable membrane assembly 40 is accommodated in the first sink S1, and the surface of the breathable membrane assembly 40 is flush with the surface of the end cap 21. In this way, the installation height of the breathable membrane assembly 40 can be reduced.

[0153] The depth of the depression of the second depression S2 relative to the first depression S1 (i.e., the height of the first transition connection surface C1) is set according to the thickness of the seal 44. Among them, the depth of the depression of the second depression S2 relative to the first depression S1 can be equal to the thickness of the seal 44, so that the second depression S2 can accommodate the seal 44. In a further embodiment, the depth of the depression of the second depression S2 relative to the first depression S1 can be slightly less than the thickness of the seal 44. In this case, when assembling the battery cell 20, the height of the space between the breathable membrane assembly 40 and the end cover 21 is slightly less than the thickness of the seal 44, so as to form an extrusion effect on the seal 44, or to make the seal 44 have an interference fit effect with the end cover 21 and the breathable membrane assembly 40. Through this setting, the interface between the seal 44 and the end cover 21, as well as the interface between the seal 44 and the breathable membrane assembly 40 can be made more tightly bonded, thereby improving the sealing performance. Among them, the seal 44 can be selected from a polymer material with a certain elasticity, which has a certain rebound tendency after being squeezed, further enhancing the bonding force between the interfaces.

[0154] In this embodiment, since the setting of the seal 44 can maintain the seal between the breathable membrane assembly 40 and the end cover 21, the connection between the breathable membrane assembly 40 and the end cover 21 only needs to provide sufficient strength to press the seal 44 without causing the sealing interface of the seal 44 to fail, and the connection between the breathable membrane assembly 40 and the end cover 21 itself no longer needs to assume the sealing function.

[0155] According to some embodiments of the present application, the breathable membrane assembly 40 is connected to the end cap 21 using a metal member 42. The metal member 42 and the end cap 21 can be welded together. In this case, the precision requirements for the welding process can be relatively low, as long as the connection strength between the metal member 42 and the end cap 21 is sufficient to press the sealing interface of the seal 44 without failure.

[0156] The first sink S1 includes a bearing surface S11 parallel to the surface of the end cap 21 and a connecting surface S12 perpendicular to the bearing surface S11. The metal member 42 is a metal sheet of a certain thickness, which can be connected to the end cap 21 using the side surface of the metal sheet. Position W1 shown in Figure 7 is the welding point between the two. The provision of a seal 44 can reduce the sealing requirements of the weld W1.

[0157] According to some embodiments of the present application, the metal member 42 may also be interference-fitted with the end cover 21. Specifically, the first sink S1 is an annular sink whose annular sidewalls enclose a receiving space, and the metal member 42 may be inserted into the space of the first sink S1, so that the side surface of the metal member 42 is interference-fitted with the connecting surface S12 of the first sink S1 to achieve a connection.

[0158] 8, 9, 10 and 11, the second sinking platform includes a platform surface S22, and a first boss 211 is provided on the second sinking platform S2, which protrudes from the platform surface S22. The first boss 211 is spaced apart from the breathable membrane 41. The spacing can reduce the risk of damaging the membrane.

[0159] In some embodiments, the height of the first boss 211 is less than the height of the first transition surface C1. The provision of the first boss 211 enables effective positioning of the seal 44. By controlling the height of the first boss 211 to be less than the height of the first transition surface C1, the first boss 211 can position the seal 44 without contacting the breathable membrane assembly 40, thereby preventing damage to the breathable membrane assembly 40.

[0160] According to some embodiments of the present application, as shown in FIG9 , first boss 211 is an annular boss surrounding first vent 291. This effectively prevents seal 44 from shifting, thereby achieving a positioning function. In other embodiments, first boss 211 may also be a plurality of non-continuous bosses, with the plurality of first bosses 211 spaced apart and arranged circumferentially around first vent 291.

[0161] Please refer to Figures 12 and 13 . Figure 12 is a schematic diagram of a partially exploded structure of a battery cell 20 according to one or more embodiments, and Figure 13 is a schematic diagram of a partially cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes a shielding member 50 , which is mounted on the end cap 21 . The shielding member 50 is located on the side of the end cap 21 facing the exterior of the housing and shields the breathable membrane assembly 40 .

[0162] In this embodiment, the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the inside of the shell, and the shielding member 50 can shield the breathable membrane assembly 40. The shielding member 50 can provide certain protection and shielding for the breathable membrane assembly 40. On the one hand, it can reduce the wear or damage of the breathable membrane assembly 40 in the external environment, and can reduce the risk of impurities or particulate matter in the external environment entering the breathable membrane assembly 40, which is beneficial to improving the service life of the breathable membrane assembly 40. On the other hand, covering the breathable membrane assembly 40 by the shielding member 50 can improve the aesthetics of the outer surface 21a of the battery cell 20. On the other hand, it is convenient to connect other components such as detection elements on the side of the shielding member 50 away from the breathable membrane assembly 40, so as to reduce the interference effect of the area where the breathable membrane assembly 40 is set on the end cover 21 on the connection of other components such as detection elements.

[0163] Please refer to Figures 10, 11, 12 and 13. 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 end cover 21 has a first sinker S1 and a fourth sinker S4 that are recessed relative to the outer surface 21a of the end cover 21. The fourth sinker S4 is arranged around the first sinker S1. The fourth sinker S4 is closer to the outer surface 21a of the end cover 21 relative to the first sinker S1. The breathable membrane assembly 40 is at least partially arranged on the first sinker S1, and the shielding member 50 is at least partially arranged on the fourth sinker S4.

[0164] The depth of the fourth depression S4 relative to the outer surface 21a of the end cap 21 can be set according to the thickness of the shielding member 50. This allows the shielding member 50 to be accommodated within the fourth depression S4, and the surface of the shielding member 50 to be flush with the outer surface 21a of the end cap 21. In this way, on the one hand, the space occupied by the shielding member 50 and the end cap 21 in the thickness direction of the end cap 21 can be reduced, and the installation height of the shielding member 50 can be reduced, which is conducive to optimizing the volume of the battery cell 20. On the other hand, the fourth depression S4 can play a certain positioning and limiting role for the shielding member 50, which is conducive to reducing the difficulty of assembling the shielding member 50 connected to the end cap 21.

[0165] Please continue to refer to Figures 10, 11, 12 and 13. According to some embodiments of the present application, the end cover 21 also has a fifth sinker S5 that is recessed relative to the outer surface 21a of the end cover 21, and the fourth sinker S4 is arranged around the fifth sinker S5. The fifth sinker S5 is located between the first sinker S1 and the fourth sinker S4.

[0166] Specifically, the end cover 21 also has a fifth sinker S5 recessed relative to the outer surface 21a of the end cover 21, a third transition connection surface C3 and a fourth transition connection surface C4, the fourth sinker S4 is arranged around the fifth sinker S5, the fifth sinker S5 is arranged around the first sinker S1, the third transition connection surface C3 connects the fifth sinker S5 and the first sinker S1, the fourth transition connection surface C4 connects the fifth sinker S5 and the fourth sinker S4, and the fourth sinker S4 is closer to the outer surface 21a of the end cover 21 than the fifth sinker S5.

[0167] Specifically, the first sinker S1, the fourth sinker S4, and the fifth sinker S5 are formed by the outer surface 21a of the end cover 21 being recessed toward the inner surface 21b of the end cover 21. The purpose of setting the first sinker S1 is to carry and accommodate the breathable membrane assembly 40, and the depth of its recess relative to the fifth sinker S5 (i.e., the height of the third transition connection surface C3) can be set according to the thickness of the breathable membrane assembly 40 so as to accommodate the breathable membrane assembly 40. The purpose of setting the fourth sinker S4 is to carry and accommodate the shielding member 50, and the depth of its recess relative to the outer surface 21a of the end cover 21 can be set according to the thickness of the shielding member 50 so as to accommodate the shielding member 50. The purpose of setting the fifth sinker S5 is to form a certain cavity between the breathable membrane assembly 40 and the shielding member 50 so that the gas can be discharged smoothly. The depth of the recess of the fifth sinker S5 relative to the fourth sinker S4 (i.e., the height of the fourth transition connection surface C4) is set according to demand. At the same time, the arrangement of the fifth sinking platform S5 can also avoid the weld mark protrusion caused by the welding connection between the metal part 42 and the wall.

[0168] According to some embodiments of the present application, the shielding member 50 can be mounted on the end cover 21 by welding, interference fit, bolting, clamping, or bonding. In order to facilitate exhaust, a gas exhaust channel needs to be reserved when assembling the shielding member 50 and the end cover 21.

[0169] Continuing with Figure 13 , a first exhaust channel is formed between the shielding member 50 and the end cap 21, connecting the air outlet of the breathable membrane assembly 40 with the exterior of the battery cell 20. The air outlet of the breathable membrane assembly 40 is either a first air hole 491 provided on the connector of the breathable membrane assembly 40 or a first exhaust hole provided on the end cap 21, depending on the location of the breathable membrane assembly 40.

[0170] In one embodiment, the first exhaust channel includes a first exhaust gap 501 formed between the shielding member 50 and the side surface of the fourth sink S4. The first exhaust gap 501 is used to connect the air outlet and the outside of the housing.

[0171] The first exhaust gap 501 is used to connect the air outlet and the outside of the shell. The first exhaust gap 501 can be directly connected to the air outlet. For example, at least part of the projection of the first exhaust gap 501 in the thickness direction X of the wall is located in the first exhaust hole, so that the air outlet of the breathable membrane assembly 40 arranged in the first exhaust hole can be directly connected to the first exhaust gap 501. Of course, the first exhaust gap 501 can also be indirectly connected to the air outlet. For example, the exhaust channel can also include a second exhaust gap. The second exhaust gap is formed between the shielding member 50 and the bottom surface of the sink of the fourth sink. The second exhaust gap connects the first exhaust gap 501 and the air outlet of the breathable membrane assembly 40.

[0172] By setting the first exhaust gap 501, the gas exhausted from the breathable membrane assembly 40 can be discharged to the outside of the shell through the first exhaust gap 501. With this structure, the battery cell 20 does not need to have a channel opened on the shielding member 50, which is conducive to reducing the processing difficulty and improving the appearance of the battery cell 20.

[0173] In one embodiment, the side of the shielding member 50 abuts and is connected to the side of the fourth sinker S4, and a protrusion (or groove) can be set on the side of the shielding member 50 to form a first exhaust gap 501 between the side of the shielding member 50 and the side of the fourth sinker.

[0174] In one embodiment, the first exhaust channel further includes a second exhaust gap (not shown), which is formed between the shielding member 50 and the bottom surface of the fourth sink S4, and connects the first exhaust gap 501 and the air outlet.

[0175] The shielding member 50 has a second surface facing the end cover 21 , and a recessed groove may be provided on the second surface. A second exhaust gap is formed between the side surface of the shielding member 50 facing the end cover 21 and the bottom surface of the fourth sinking platform.

[0176] Please refer to Figures 17a and 17b. Figure 17a is a schematic diagram of the exploded structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes a protective patch 60, which is disposed on the side of the end cap 21 facing the exterior of the housing. Specifically, the protective patch 60 is disposed on the outer surface 21a of the end cap 21 to provide a certain degree of protection for the end cap 21. The protective patch 60 can be made of a variety of materials, such as rubber, silicone, or plastic.

[0177] According to some embodiments of the present application, an information collection hole 601 is provided on the protective patch 60 and penetrates the protective patch 60. The information collection hole 601 serves as a part of the exposed end cover 21, so as to facilitate setting an information code on the end cover 21 or connecting a detection element for sampling, etc.

[0178] According to some embodiments of the present application, in an embodiment in which an electrode terminal 25 is provided on the end cap 21, as shown in FIG17a , a first avoidance hole 602 is provided on the protective patch 60 at a position corresponding to the electrode terminal 25. The first avoidance hole 602 runs through both sides of the protective patch 60. The first avoidance hole 602 is used to allow the electrode terminal 25 to pass through, avoiding the electrode terminal 25. Exemplarily, two electrode terminals 25 are provided on the end cap 21, and correspondingly, the protective patch 60 is provided with two first avoidance holes 602, each of which is used to allow one electrode terminal 25 to pass through.

[0179] In an embodiment in which a pressure relief mechanism 70 is provided on the end cover 21, as shown in Figure 17a, a second avoidance hole 603 is provided at the position of the protective patch 60 corresponding to the pressure relief mechanism 70. The second avoidance hole 603 runs through both sides of the protective patch 60, and the positive projection of the pressure relief mechanism 70 on the protective patch 60 is located in the second avoidance hole 603, so that the second avoidance hole 603 can avoid the pressure relief mechanism 70.

[0180] According to some embodiments of the present application, the breathable membrane assembly 40 can be provided on the side of the end cap 21 facing the interior of the housing. In this case, the first exhaust hole 291 will be exposed to the appearance of the end cap 21, such as the first exhaust hole 291-1 in Figure 17a (wherein, the first exhaust hole 291-1 and the first exhaust hole 291-2 shown in Figure 17a are for respectively illustrating the difference between the end cap 21 in two cases where the breathable membrane assembly 40 is provided on the side of the end cap 21 facing the interior of the housing and the breathable membrane assembly 40 is provided on the side of the end cap 21 facing the outside of the housing. In actual products, one of the breathable membrane assemblies 40 will be selectively provided according to the location of the breathable membrane assembly 40. Of course, two breathable membrane assemblies 40 can also be provided on the battery cell 20, and both can exist at the same time). In this embodiment, the first exhaust hole 291 can be directly covered with a protective patch 60. On the one hand, it can reduce the risk of impurities or particulate matter in the external environment entering the first exhaust hole 291 to prevent poor exhaust. On the other hand, it can keep the appearance of the end cover 21 unchanged, which is conducive to expanding its application to different products without affecting the appearance of the original product.

[0181] According to some embodiments of the present application, the breathable membrane assembly 40 may be disposed on the side of the end cap 21 facing the outside of the housing. In this case, the shielding member 50 covering the breathable membrane assembly 40 is exposed from the appearance of the end cap 21 .

[0182] According to some embodiments of the present application, the orthographic projection of the information collection hole 601 on the end cap 21 is located within the shielding member 50. That is, the information collection hole 601 is arranged corresponding to the shielding member 50, so that the exposed area of ​​the information collection hole 601 is the surface of the shielding member 50, thereby enabling the shielding member 50 to be provided with an information code or connected to a detection element for sampling.

[0183] According to some embodiments of the present application, the protective patch 60 may be provided on the end cover 21 in various structures, and the protective patch 60 may be provided on the end cover 21 by bonding, adsorption, or the like.

[0184] When the adhesive method is used, the adhesive layer 610 adheres the protective patch 60 and the end cover 21 , and the adhesive layer 610 is provided with an avoidance groove 611 , and a second discharge channel is formed between the avoidance groove 611 and the end cover 21 , and the second discharge channel connects the first exhaust hole and the outside of the battery cell 20 .

[0185] Please refer to Figure 17b, which is a bottom view of the adhesive layer of the protective patch 60 according to one or more embodiments. The adhesive layer 610 is provided with an escape groove 611. In some embodiments, the orthographic projection of the air outlet on the protective patch 60 is located within the escape groove 611 area.

[0186] 13 , the end cap 21 includes an end cap 21 main body 210, the end cap 21 main body 210 having an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a being disposed toward the outside of the shell, and the inner surface 21b being disposed toward the inside of the shell, the end cap 21 having a wall boss 212 protruding relative to the inner surface 21b; the orthographic projection of the wall boss 212 on the end cap 21 main body at least partially overlaps with the orthographic projection of the breathable membrane assembly 40 on the end cap 21 main body.

[0187] In other words, viewed from the thickness direction of the end cover 21, the wall boss 212 strengthens the thickness of the end cover 21 in the area where the breathable membrane assembly 40 is located, thereby increasing the strength of the end cover 21 and compensating for the decrease in strength of the end cover 21 caused by the formation of the sink.

[0188] Please refer to Figures 14, 15, and 16a. Figure 14 is a schematic diagram of a partially exploded structure of a battery cell 20 according to one or more embodiments, Figure 15 is a schematic diagram of a partial cross-sectional structure of an insulating member 24 according to one or more embodiments, and Figure 16a is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes an insulating member 24, which is disposed on the side of the end cap 21 facing the interior of the housing; that is, an insulating member 24 may also be disposed on the inner side of the end cap 21. The insulating member 24 can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits.

[0189] For example, the insulating member 24 may be made of plastic, rubber, etc.

[0190] The insulating member 24 includes a main body 242 , which is made of a material that will not contact the electrode assembly 23 inside the battery 100 to cause a short circuit. The main body 242 is used to protect the end cap 21 from being directly exposed to the electrode assembly 23 in the height direction to prevent contact with the electrode assembly 23 to cause a short circuit.

[0191] The insulating member 24 is provided with a second vent hole 292 that penetrates the main body 242 of the insulating member 24, so that gas inside the battery 100 can enter the area of ​​the breathable membrane assembly 40 through the first vent hole 291. In some embodiments, the second vent hole 292 is connected to the first vent hole 291 to facilitate exhaust.

[0192] Continuing with Figures 14, 15, and 16a, according to some embodiments of the present application, the insulating member 24 is provided with a second boss 241 that protrudes from the main body 242. The second boss 241 is disposed around the second vent hole 292 and extends toward the end cap 21 into the first vent hole 291. By extending the second boss 241 to the region of the first vent hole 291 in the end cap 21, the sidewall of the first vent hole 291 can be blocked outside the second boss 241, thereby achieving an insulating effect.

[0193] In one embodiment, the second boss 241 is spaced apart from the breathable membrane 41. The spaced apart arrangement can reduce the risk of damaging the membrane.

[0194] In some embodiments, the extension height of the second boss 241 is lower than the top of the first exhaust hole 291, that is, the second boss 241 can extend into the first exhaust hole 291, but will not pass through the area of ​​the first exhaust hole 291, so that the second boss 241 will not touch the breathable membrane assembly 40 to prevent damage to the breathable membrane assembly 40.

[0195] According to some embodiments of the present application, when the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the outside of the shell, the sink design on the end cover 21 will cause the end cover 21 to have a protruding area facing the inside of the shell. At this time, an accommodating portion that is recessed relative to the surface of the insulating member 24 can be provided on the main body 242 of the insulating member 24 to accommodate the protruding portion of the end cover 21.

[0196] Referring to Figure 16a, the main body 242 of the insulating member 24 has an upper surface 242a that faces the end cap 21. The main body 242 of the insulating member 24 has a sixth recessed portion S6 that is recessed relative to the upper surface 242a. The wall boss 212 is at least partially located on the sixth recessed portion S6. This arrangement accommodates the wall boss 212, reduces the installation height, and reduces the space occupied by the interior of the housing.

[0197] Please refer to Figure 16b, which is a schematic partial cross-sectional view of a battery cell 20 according to one or more embodiments. The battery cell 20 further includes an adapter plate 26 having a first surface 26a disposed toward the insulating member 24. The adapter plate 26 includes a seventh recessed portion S7 recessed relative to the first surface 26a. The main body 242 of the insulating member 24 includes a main body protrusion 2421 protruding relative to the lower surface of the main body 242 of the insulating member 24. The main body protrusion 2421 is at least partially located within the seventh recessed portion S7. This arrangement allows for the wall protrusion 212 to be accommodated, reducing the installation height and the space occupied within the housing.

[0198] In some examples, a portion of the lower surface of the adapter plate 26 opposite to the seventh sink S7 protrudes toward the interior of the battery cell 20 to enhance the strength of the adapter plate 26 .

[0199] According to some embodiments of the present application, as shown in Figures 1 and 2, the battery cell 20 also includes a pressure relief mechanism 70, which is disposed on the outer shell and is configured to actuate and release the internal pressure of the battery cell 20 when the battery cell 20 thermally runs away.

[0200] The pressure relief mechanism 70 is provided on the outer shell, and may be provided on the end cover 21 or on the shell 22 . For example, in FIG. 1 , the pressure relief mechanism 70 is provided on the end cover 21 .

[0201] The pressure relief mechanism 70 is configured to activate and release the internal pressure of the battery cell 20 when the battery cell 20 experiences thermal runaway. Specifically, when thermal runaway occurs within the battery cell 20, the pressure relief mechanism 70 can activate and open to release gases generated within the battery cell 20 due to thermal runaway. It should be noted that when thermal runaway occurs within the battery cell 20, the gas inside the outer casing of the battery cell 20 will rapidly surge, causing the pressure relief mechanism 70 to open and release the pressure. However, during normal use, gases generated within the outer casing of the battery cell 20 can be discharged through the vent assembly 40, but this does not allow the pressure relief mechanism 70 to open.

[0202] Optionally, the pressure relief mechanism 70 and the housing can be an integrally formed structure or a separately provided structure. If the pressure relief mechanism 70 and the housing are an integrally formed structure, the pressure relief mechanism 70 is an area on the housing where a weak structure is provided, for example, an area on the housing where a notched groove is provided. If the pressure relief mechanism 70 and the housing can be a separate structure, the pressure relief mechanism 70 can be connected to the housing by welding, hot melting, injection molding, or bonding. For example, in FIG2 , the pressure relief mechanism 70 and the housing are separately provided, and the pressure relief mechanism 70 is provided on the end cover 21 of the housing. The pressure relief mechanism 70 can be a pressure relief component such as an explosion-proof valve, an explosion-proof disk, a pressure relief valve, or a safety valve.

[0203] For example, in Figure 1, the electrode terminal 25 and the pressure relief mechanism 70 are both arranged on the end cover 21. The battery cell 20 adopting this structure can save the space occupied by the battery cell 20. Of course, in other embodiments, the electrode terminal 25 and the pressure relief mechanism 70 can also be arranged on different walls of the outer shell. The battery cell 20 adopting this structure can make the electrode terminal 25 of the battery cell 20 used to output or input electrical energy and the pressure relief mechanism 70 used to release internal pressure stay away from each other to reduce the risk of using the battery cell 20. For example, the pressure relief mechanism 70 is arranged on the shell 22, and the electrode terminal 25 is arranged on the end cover 21.

[0204] By providing a breathable membrane assembly 40, when gas is generated inside the shell during normal use of the battery cell 20, it can be discharged to the outside of the shell through the breathable membrane assembly 40, thereby alleviating the phenomenon of premature actuation of the pressure relief mechanism 70 before the thermal runaway of the battery cell 20 due to the increase in internal air pressure of the battery cell 20, thereby effectively improving the use stability of the battery cell 20 and improving the service life and reliability of the battery cell 20.

[0205] In some embodiments, the breathable membrane assembly 40 and the pressure relief mechanism 70 may be disposed on the same wall of the housing. For example, the breathable membrane assembly 40 and the pressure relief mechanism 70 may both be disposed on the end cap 21. A battery cell 20 employing this structure can help conserve space within the battery cell 20 and increase the energy density of the battery cell 20.

[0206] In some embodiments, the breathable membrane assembly 40 and the pressure relief mechanism 70 may be mounted on different walls of the housing. For example, the breathable membrane assembly 40 may be mounted on the housing 22, while the pressure relief mechanism 70 may be mounted on the end cap 21. A battery cell 20 employing this structure can minimize the interaction between the breathable membrane assembly 40 and the pressure relief mechanism 70 and is adaptable to various operating environments.

[0207] In some embodiments, the breathable membrane assembly 40 is positioned on the top wall of the housing when the battery cell 20 is in a resting state. That is, regardless of the operating environment of the battery cell 20, the upward-facing wall is the top wall when the battery cell 20 is resting. Placing the breathable membrane assembly 40 on the top wall not only ensures the stable placement of the battery 100 but also prevents the exhaust passage from being blocked by objects in the external environment, providing more space for exhaust. Furthermore, gases are generally low in density and light in weight, tending to move upward. Placing the breathable membrane assembly 40 on the top wall facilitates smooth exhaust.

[0208] In some embodiments, the air permeability of the breathable membrane 41 is 3-10 mL / day. Alternatively, the air permeability may be 3-4 mL / day, 4-6 mL / day, 5-8 mL / day, or 9-10 mL / day. The air permeability of the breathable membrane 41 may be tested according to GB / T 1038-2000.

[0209] By setting the permeability rate of the breather membrane 41 to 3-10 mL / day, the phenomenon of excessively rapid degassing of the breather membrane assembly 40, which could prevent the pressure relief mechanism 70 from activating and opening, can be mitigated when a battery cell 20 experiences thermal runaway. This allows the pressure relief mechanism 70 to activate and stably release the internal pressure of the battery cell 20 when thermal runaway occurs, thereby reducing the risk of fire and explosion in the battery cell 20. The airtightness of the system is also taken into consideration to prevent excessive degassing, which could lead to a deterioration in the airtightness of the system. This ensures that the airtightness of the battery 100 system is maintained while the gas is discharged.

[0210] In some embodiments, the thickness of the breathable membrane 41 is 0.1-3.0 mm, and optionally 0.2-0.8 mm, for example, 0.1 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, etc. The air permeability of the breathable membrane 41 can be controlled.

[0211] In some embodiments, the battery cell 20 is an alkali metal battery 100, such as a sodium metal battery 100 or a lithium metal battery 100. The alkali metal battery 100, when used in conjunction with the breathable membrane assembly 40, can promptly discharge gases generated by the alkali metal battery 100 during normal operation, thereby extending the service life of the alkali metal battery 100.

[0212] The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets containing active materials constitute the main body of the electrode assembly 23, and the parts of the positive and negative electrode sheets without active materials each constitute the tabs. The positive and negative electrode tabs can 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 100, the positive and negative electrode active materials react with the electrolyte, and the tabs are connected to the electrode terminals 25 to form a current circuit.

[0213] 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, wherein the positive electrode active layer includes a positive electrode active material.

[0214] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active layer may be provided on either or both of the two facing surfaces of the positive electrode current collector.

[0215] 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 layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0216] In one embodiment, the positive electrode material includes one or more of a polyanion-based positive electrode material, a phosphate-based positive electrode material, a sulfate-based positive electrode material, a silicate-based positive electrode material, and a borate-based positive electrode material. For example, in the positive electrode active material of the sodium battery 100, the polyanion-based compound includes compounds based on phosphoric acid and fluorophosphate. Phosphate-based compounds include Nax1Fey1Pm1On1, for example, sodium iron phosphate with a higher capacity and sodium iron pyrophosphate with a higher voltage platform. The polyanion-based compound includes one or more of sodium vanadium trifluorophosphate Na3V2(PO4)2F3, sodium vanadium fluorophosphate NaVPO4F, sodium vanadium phosphate Na3V2(PO4)3, Na4Fe3(PO4)2P2O7, NaFePO4, and Na3V2(PO4)3. The Prussian blue compound is NaxMM(CN)6, where M and M are one or more of Fe, Mn, Co, Ni, Cu, Zn, Cr, Ti, V, Zr, and Ce, and 0 < x ≤ 2. The positive electrode active material in the lithium metal battery 100 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.

[0217] In one embodiment, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode active layer includes a negative electrode active material. In this embodiment, the battery cell 20 is an ion battery 100. During the charge and discharge process of the battery 100, active ions (such as Li+ and Na+) are intercalated and deintercalated in the negative electrode active material.

[0218] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active layer may be disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0219] In one embodiment, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. 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 base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0220] 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, a silicon oxide (e.g., silicon 2 oxide), a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The selenium-based material may be selected from one or more of elemental selenium, a selenium oxide, and a selenium alloy.

[0221] In one embodiment, the negative electrode plate includes a negative electrode current collector and a carbon-containing coating provided on at least one surface of the negative electrode current collector. In this embodiment, the battery cell 20 is a metal battery 100, and during the charge and discharge process of the battery 100, active ions are deposited / stripped at the negative electrode plate. The metal battery 100 can be an alkali metal battery 100, such as a lithium metal battery 100, a sodium metal battery 100, a potassium metal battery 100, a zinc metal battery 100, or an aluminum metal battery 100. This type of battery 100 can also be called a "negative electrode-free battery 100". 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 the carbon-containing coating facilitates more uniform metal deposition. The carbon-containing material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

[0222] In other embodiments, a conductive film layer may be deposited on the negative electrode current collector. Examples include alloy materials, titanium-based materials, active metals (e.g., sodium metal), carbon-based materials deposited with metals, composite materials containing metals, and alloy materials containing metals. Such alloy materials include, but are not limited to, sodium-tin alloys, sodium-germanium alloys, and sodium-antimony alloys. Such titanium-based materials include, but are not limited to, titanium dioxide, titanates, and titanium phosphates.

[0223] In one embodiment, the positive electrode active layer and the negative electrode active layer may further include a binder and a conductive agent. As an example, the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and at least one of a 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.

[0224] In one embodiment, the isolation membrane can be any known porous structure isolation membrane with good chemical stability and mechanical stability.

[0225] In one embodiment, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0226] The electrolyte conducts ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid.

[0227] 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.

[0228] In one embodiment, the electrolyte salt in the sodium battery 100 includes sodium salts such as sodium hexafluorophosphate (NaPF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium trifluoromethanesulfonate (CF3NaO3S), and sodium sulfide (Na2S). The lithium battery 100 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.

[0229] In one embodiment, the solvent includes one or more solvents selected from the group consisting 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, specifically 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, trifluoroethyl methyl carbonate (FEMC), dioxolane (DOL), acetonitrile (AN), fluorobenzene, triethyl phosphate (TEP), sulfolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylacetamide, and the like.

[0230] 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 additives capable of improving certain properties of the battery 100, such as additives that improve the overcharge performance of the battery 100, and additives that improve the high or low temperature performance of the battery 100.

[0231] According to some embodiments of the present application, a battery 100 is provided, comprising a battery cell 20 according to any of the above-described embodiments. Referring to FIG. 18 , FIG. 18 is a schematic diagram of an exploded structure of the battery 100 according to one or more embodiments. The battery 100 comprises a housing 10 and a battery cell 20, with the battery cell 20 contained within the housing 10. The housing 10 is configured to provide a storage space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap with each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open, and the first portion 11 can be a plate-like structure, overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. Alternatively, the first portion 11 and the second portion 12 can each be a hollow structure with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 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.

[0232] 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 hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery 100 may be housed within the housing 10. Of course, the battery 100 may also be in the form of a battery module 100, in which multiple battery cells 20 are first connected in series, in parallel, or in a hybrid connection, and then the multiple battery modules 100 are further connected in series, in parallel, or in a hybrid connection to form an entire battery 100, and then housed within the housing 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for electrically connecting the multiple battery cells 20.

[0233] Each battery cell 20 may be a secondary battery 100 or a primary battery 100; specific examples include all types of primary batteries 100 or secondary batteries 100. For example, it may be a lithium battery 100, a sodium battery 100, a potassium battery 100, or other types of secondary batteries 100. A lithium secondary battery 100 may include a lithium metal secondary battery 100, a lithium ion secondary battery 100, a lithium polymer secondary battery 100, or a lithium ion polymer secondary battery 100. Alternatively, it may be a lithium sulfur battery 100, a sodium ion battery 100, or a magnesium ion battery 100, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or have other shapes.

[0234] In some embodiments, the battery 100 may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0235] According to some embodiments of the present application, the present application further provides an electric device, which includes a battery cell 20 according to any of the above solutions, and the battery cell 20 is used to provide power to the electric device. The electric device can be any of the above devices or systems using the battery cell 20.

[0236] 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 100 disclosed in the embodiment of the present application can be used for electric equipment using the battery 100 as a power source or various energy storage systems using the battery 100 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, laptop 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 100 and lithium-ion capacitors, etc.

[0237] The electric device can select the battery cell 20, battery module 100 or battery pack according to its usage requirements.

[0238] Please refer to Figure 19, which is a schematic structural diagram of a vehicle 1000 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 provided inside the vehicle 1000, and the battery 100 can be provided 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 serve 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 starting, navigating and driving the vehicle 1000.

[0239] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also 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.

[0240] In the above embodiment, the provision of a breathable membrane assembly 40 enables the battery cell 20 to discharge internal gas through the breathable membrane 41 while in a sealed state, promptly discharging the internal gas of the battery 100 housing to the outside of the housing. This prevents excessive pressure inside the battery 100 housing, reduces the risk of premature valve opening of the pressure relief mechanism 70, and significantly improves the lifespan of the battery 100. One or more breathable membrane assemblies 40 can be provided on a single battery cell 20, and the placement and manner of each breathable membrane assembly 40 can vary. For example, one breathable membrane assembly 40 can be provided on the side of the end cap 21 facing the interior of the battery 100 housing, and another breathable membrane assembly 40 can be provided on the side of the end cap 21 facing the exterior of the battery 100 housing. Alternatively, one breathable membrane assembly 40 can be provided on the end cap 21, and another breathable membrane assembly 40 can be provided on the housing 22.

[0241] The above 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 description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that, comprising: a housing having a wall portion, the wall portion having a first exhaust hole that communicates the interior of the housing with the exterior of the housing; a breathable membrane assembly disposed on the wall portion, the breathable membrane assembly including a breathable membrane that covers the first exhaust hole.

2. The battery cell according to claim 1, characterized in that, the battery cell further includes a seal disposed between the breathable membrane assembly and the wall portion.

3. The battery cell according to claim 2, characterized in that, the seal is disposed between the breathable membrane and the wall portion.

4. The battery cell according to claim 2 or 3, characterized in that, the seal is disposed around the first exhaust hole, the seal is provided with a second breathable hole, the aperture of the second breathable hole is larger than the aperture of the first exhaust hole, and the breathable membrane covers the second breathable hole.

5. The battery cell according to any one of claims 2 to 4, characterized in that, the breathable membrane assembly further includes a connecting member provided with a first breathable hole, the breathable membrane is disposed on the connecting member, the breathable membrane covers the first breathable hole, and the breathable membrane is disposed between the connecting member and the seal.

6. The battery cell according to any one of claims 2 to 5, characterized in that, the wall portion has a first sink and a second sink recessed with respect to the surface of the wall portion, the first sink surrounds the second sink, the first sink is closer to the surface of the wall portion than the second sink, the second sink surrounds the first exhaust hole, at least a part of the seal is located on the second sink, and at least a part of the breathable membrane assembly is located on the first sink.

7. The battery cell according to claim 6, characterized in that, the second sink includes a platform surface, and a first boss protruding from the platform surface is further provided on the second sink, and the first boss is spaced apart from the breathable membrane.

8. The battery cell according to claim 7, characterized in that, the first boss is an annular boss surrounding the first exhaust hole; or the first boss is plural, and the plural first bosses are spaced apart in the circumferential direction of the first exhaust hole.

9. The battery cell according to any one of claims 5 to 8, characterized in that, the connecting member is welded to the wall portion; or the connecting member is in interference fit with the wall portion.

10. The battery cell according to claim 1, characterized in that, the wall portion has a first sink recessed with respect to the surface of the wall portion, the first sink surrounds the first exhaust hole, and at least a part of the breathable membrane assembly is located on the first sink.

11. The battery cell according to claim 10, characterized in that, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface faces the exterior of the housing, the inner surface faces the interior of the housing, and the wall portion has a first sink recessed with respect to the inner surface of the wall portion.

12. The battery cell according to claim 11, It is characterized in that the wall portion further has a third sunk platform recessed relative to the inner surface of the wall portion, the first sunk platform is arranged around the third sunk platform, the first sunk platform is closer to the inner surface than the third sunk platform, and the third sunk platform is arranged around the first exhaust hole.

13. The battery cell according to claim 11 or 12, It is characterized in that the breathable film assembly further includes a connecting member, the connecting member is arranged on the first sunk platform, and the connecting member is provided with a first breathable hole; the breathable film is arranged on one side of the connecting member facing the inside of the housing, and the breathable film covers the first breathable hole; or the breathable film is arranged on one side of the connecting member facing the wall portion, and the breathable film covers the first breathable hole.

14. The battery cell according to claim 13, It is characterized in that the orthographic projection of the first breathable hole on the wall portion does not overlap with the area where the first exhaust hole is located.

15. The battery cell according to any one of claims 1 to 14, It is characterized in that the breathable film assembly is arranged on one side of the wall portion facing the inside of the housing.

16. The battery cell according to any one of claims 1 to 10, It is characterized in that the breathable film assembly is arranged on one side of the wall portion facing the outside of the housing.

17. The battery cell according to claim 16, It is characterized in that the wall portion has an outer surface and an inner surface arranged opposite to each other, the outer surface faces the outside of the housing, the inner surface faces the inside of the housing, the wall portion has a first sunk platform recessed relative to the outer surface, and at least part of the breathable film assembly is located in the first sunk platform.

18. The battery cell according to claim 17, It is characterized in that the breathable film assembly further includes a connecting member, the connecting member is arranged on the first sunk platform, and the connecting member is provided with a first breathable hole; the breathable film is arranged on one side of the connecting member facing the wall portion, and the breathable film covers the first breathable hole.

19. The battery cell according to any one of claims 16 to 18, It is characterized in that the wall portion includes a wall portion main body, the wall portion main body has an outer surface and an inner surface arranged opposite to each other, the outer surface faces the outside of the housing and is arranged, the inner surface faces the inside of the housing, and the wall portion has a wall portion boss protruding relative to the inner surface; the orthographic projection of the wall portion boss on the wall portion main body at least partially overlaps with the orthographic projection of the breathable film assembly on the wall portion main body.

20. The battery cell according to any one of claims 16 to 19, It is characterized in that the battery cell further includes: an insulating member, arranged on one side of the wall portion facing the inside of the housing; a second exhaust hole penetrating through the insulating member is arranged on the insulating member, and the second exhaust hole is communicated with the first exhaust hole.

21. The battery cell according to claim 20, It is characterized in that the insulating member is provided with a second boss protruding from the insulating member, the second boss is arranged around the second exhaust hole, and the second boss extends towards the wall portion into the first exhaust hole.

22. The battery cell according to claim 21, wherein, the second boss is spaced apart from the breathable film.

23. The battery cell according to any one of claims 20 to 22, wherein, the insulating member has an upper surface facing the wall portion, the upper surface has a sixth sink relative to the upper surface, the wall portion has a wall boss protruding from the inner surface of the wall portion, and at least a part of the wall boss is located in the sixth sink.

24. The battery cell according to any one of claims 16 to 23, wherein, the battery cell further includes: a connecting piece having a first surface facing the insulating member, the first surface has a seventh sink relative to the first surface, the insulating member has a body boss protruding from the lower surface of the insulating member, and at least a part of the body boss is located in the seventh sink.

25. The battery cell according to any one of claims 17 to 24, wherein, the battery cell further includes: a shielding member mounted on the wall portion, the shielding member is located on a side of the wall portion facing the outside of the housing and shields the breathable film assembly; wherein, a first discharge channel is formed between the shielding member and the wall portion, and the first discharge channel communicates the air outlet of the breathable film assembly with the outside of the battery cell.

26. The battery cell according to claim 25, wherein, the wall portion has a fourth sink recessed relative to the outer surface of the wall portion, the fourth sink surrounds the first sink, the fourth sink is closer to the outer surface than the first sink, at least a part of the breathable film assembly is disposed on the first sink, and at least a part of the shielding member is disposed on the fourth sink.

27. The battery cell according to claim 26, wherein, the wall portion further has a fifth sink recessed relative to the outer surface, the fourth sink surrounds the fifth sink, and the fifth sink is located between the fourth sink and the first sink.

28. The battery cell according to any one of claims 25 to 27, wherein, the first discharge channel includes a first exhaust gap formed between the shielding member and the side surface of the sink of the fourth sink, and the first exhaust gap is used to communicate the air outlet with the outside of the housing.

29. The battery cell according to claim 28, wherein, the first discharge channel further includes a second exhaust gap formed between the shielding member and the bottom surface of the sink of the fourth sink, and the second exhaust gap communicates the first exhaust gap with the air outlet.

30. The battery cell according to any one of claims 25 to 29, wherein, the battery cell further includes: a protective patch disposed on a side of the wall portion facing the outside of the housing, and the protective patch covers the shielding member.

31. The battery cell according to claim 30, wherein, The protective patch is provided with an information collection hole penetrating through the protective patch, and the orthographic projection of the information collection hole on the wall portion is located within the shielding member.

32. The battery cell according to any one of claims 1 to 15, characterized in that the battery cell further comprises: a protective patch, which is arranged on the side of the wall portion facing the outside of the housing, and the protective patch covers the first exhaust hole.

33. The battery cell according to any one of claims 30 to 32, characterized in that a bonding layer is arranged on the side of the protective patch facing the wall portion, the bonding layer bonds the protective patch and the wall portion, the bonding layer is provided with an avoidance groove, and a second discharge channel is formed between the avoidance groove and the wall portion, and the second discharge channel communicates the first exhaust hole and the outside of the battery cell.

34. The battery cell according to any one of claims 1 to 33, characterized in that the breathable film assembly further comprises a connecting member, the connecting member is provided with a first breathable hole, the breathable film is arranged on the connecting member, and the breathable film covers the first breathable hole.

35. The battery cell according to claim 34, characterized in that the connecting member has a first annular table surface recessed relative to the surface of the connecting member, the first annular table surface surrounds the first breathable hole, and the breathable film is arranged on the first annular table surface.

36. The battery cell according to claim 34 or 35, characterized in that the breathable film assembly further comprises a backing member, the backing member is arranged between the breathable film and the connecting member, and the air permeability rate of the backing member is greater than that of the breathable film.

37. The battery cell according to claim 36, characterized in that the connecting member further has a second annular table surface recessed relative to the surface of the connecting member, the second annular table surface surrounds the first breathable hole, and the backing member is at least partially arranged on the second annular table surface; Optionally, the area of the groove where the second annular table is located is 30 mm 2 -250 mm 2 Optionally, the area of the groove where the second annular table is located is 60 mm 2 -200 mm 2 .

38. The battery cell according to any one of claims 34 to 37, characterized in that the first breathable hole comprises a plurality of circular through holes, and the diameter of the circular through holes is less than 3.0 mm.

39. The battery cell according to any one of claims 34 to 38, characterized in that the connecting member is a metal member.

40. The battery cell according to any one of claims 1 to 39, characterized in that the thickness of the breathable film is 0.1 - 3.0 mm, optionally, the thickness is 0.2 - 0.8 mm.

41. The battery cell according to any one of claims 1 to 40, characterized in that the air permeability rate of the breathable film is 3 - 10 mL / day; optionally, the air permeability rate is 4 - 6 mL / day.

42. The battery cell according to any one of claims 1 to 41, characterized in that the housing comprises: a housing body, which forms an accommodating cavity with an opening inside, and the accommodating cavity is used for accommodating the electrode assembly; an end cover, which closes the opening; wherein, the end cover is the wall portion; or the housing body comprises the wall portion; or The wall portion is the wall located at the top of the housing when the battery cell is in the placed state.

43. The battery cell according to any one of claims 1 to 42, wherein, a pressure relief mechanism is provided in the housing, and the pressure relief mechanism is configured to actuate and release the internal pressure of the battery cell when the battery cell undergoes thermal runaway.

44. A battery, wherein, it includes the battery cell according to any one of claims 1 - 43.

45. An electrical device, wherein, it includes the battery cell according to any one of claims 1 - 43, and the battery cell is used to provide electrical energy.

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