Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, a gas permeable valve and a sealing member. The shell has a wall portion provided with a first gas permeable hole. The gas permeable valve comprises a limiting member and a gas permeable film. The limiting member is connected to the wall portion and is provided with a second gas permeable hole corresponding to the first gas permeable hole. The first gas permeable hole and the second gas permeable hole are respectively located on two sides of the gas permeable film along the thickness direction of the wall portion. The sealing member is arranged around the first gas permeable hole and at least partially abuts between the gas permeable film and the wall portion. The gas permeable film comprises a first area. In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the first area is arranged around the orthographic projection of the sealing member, and the first area at least partially abuts between the limiting member and the wall portion. By making the first area at least partially abut between the limiting member and the wall portion, the risk of wrinkles on the gas permeable film is reduced, the gas permeability of the gas permeable film is maintained, and the reliability of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability also needs to be considered. However, current battery reliability is relatively poor. Utility Model Content

[0003] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to improve the problem of poor battery reliability in related technologies.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a shell, a vent valve, and a seal. The shell has a wall portion, and the wall portion is provided with a first vent hole. The vent valve includes a limiting member and a vent membrane. The limiting member is connected to the wall portion and is provided with a second vent hole, the second vent hole being disposed corresponding to the first vent hole. Along the thickness direction of the wall portion, the first vent hole and the second vent hole are respectively located on both sides of the vent membrane. The seal is disposed around the first vent hole and at least partially abuts against the vent membrane and the wall portion. The vent membrane includes a first region. In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the first region is disposed around the orthographic projection of the seal, and the first region at least partially abuts against the limiting member and the wall portion.

[0005] In the above technical solution, the battery cell is equipped with a vent valve. When the internal air pressure of the battery cell increases, the vent valve allows gas to be released from the inside of the battery cell, thereby reducing the internal pressure of the battery cell and improving its reliability. Since the vent membrane prevents liquid from passing through, a sealing element is provided between the vent membrane and the wall to seal the vent membrane and the wall, reducing the risk of electrolyte leakage and the risk of impurities from outside the battery cell entering the battery cell, thus improving the reliability of the battery cell. By ensuring that the first region at least partially abuts against the limiting element and the wall, the limiting element and the wall can cooperate to support and limit the first region, reducing the risk of wrinkles appearing in the vent membrane during battery cell use. This allows the vent membrane to stably cover the first vent hole, maintaining the permeability of the vent membrane and thus improving the reliability of the battery cell. In addition, when the limiting member is welded to the wall, the heat of welding may cause the first area to partially melt. After the first area melts, it is still confined between the limiting member and the wall. As the welding is completed and the temperature drops, the molten fluid in the first area will solidify and return to its original state, so that the breathable membrane can stably cover the first vent. This helps to maintain the breathability of the breathable membrane and thus improve the reliability of the battery cell.

[0006] As an optional technical solution in this application embodiment, the wall portion has a first surface, the first surface is provided with a first groove, and the bottom wall of the first groove is provided with a first vent hole; the sealing member is at least partially accommodated in the first groove, and the sealing member abuts between the vent membrane and the bottom surface of the first groove, the vent membrane covers the first groove, and the first area at least partially abuts between the limiting member and the first surface.

[0007] In the above technical solution, by providing a first groove on the first surface, the sealing element is easily accommodated, reducing the height of the sealing element protruding from the first surface. This allows the breathable membrane to be positioned relatively flat between the limiting element and the wall, reducing the risk of tearing and deformation of the breathable membrane, maintaining its breathability, and thus improving the reliability of the battery cell. By ensuring that the first area at least partially abuts against the limiting element and the first surface, the limiting element and the wall can cooperate to support and limit the first area, reducing the risk of wrinkles appearing in the breathable membrane during battery cell use. This allows the breathable membrane to stably cover the first vent, maintaining its breathability and further improving the reliability of the battery cell.

[0008] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the surface of the sealing member facing the breathable membrane is flush with the first surface.

[0009] In the above technical solution, by making the surface of the sealing member facing the breathable membrane along the thickness direction of the wall flush with the first surface, the breathable membrane can be more evenly placed between the limiting member and the wall, which is more conducive to reducing the risk of the breathable membrane being stretched and deformed, and more conducive to maintaining the breathability of the breathable membrane, thereby improving the reliability of the battery cell.

[0010] As an optional technical solution in this application embodiment, the wall portion is provided with a second groove, the bottom surface of the second groove is the first surface, and the limiting member is at least partially accommodated in the second groove.

[0011] In the above technical solution, by providing a second groove on the wall and having the limiting member at least partially accommodated in the second groove, the height of the limiting member protruding from the outer or inner surface of the wall is reduced, thereby reducing the risk of interference between the limiting member and other components.

[0012] As an optional technical solution in this application embodiment, the first area is entirely abutted between the limiting member and the first surface, and the first area completely covers the first surface.

[0013] In the above technical solution, by ensuring that the first region completely covers the first surface, the large area of ​​the first region allows the limiting member to press the larger area of ​​the first region against the first surface. This enhances the support and limiting effect on the first region, reduces the risk of wrinkles in the venting membrane during battery cell use, and ensures that the venting membrane stably covers the first vent hole, maintaining its permeability and thus improving the reliability of the battery cell. Furthermore, when the limiting member is welded to the wall, the heat from welding may partially melt the first region. Since the first region completely covers the first surface, the molten fluid has no space to flow and remains in its original position. As welding completes and the temperature drops, the molten fluid in the first region solidifies, returning to its original state. This allows the venting membrane to stably cover the first vent hole, maintaining its permeability and further improving the reliability of the battery cell.

[0014] As an optional technical solution in this application embodiment, the first area is completely abutted between the limiting member and the first surface, and there is a distance between the outer peripheral surface of the breathable membrane and the groove side surface of the second groove.

[0015] In the above technical solution, by creating a distance between the outer peripheral surface of the breathable membrane and the side surface of the second groove, the size of the breathable membrane can be reduced, thus lowering its cost. Furthermore, it helps to reduce assembly difficulty.

[0016] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the orthographic projection of the outer peripheral surface of the breathable membrane is circular, the orthographic projection of the groove side of the second groove is circular, the diameter of the groove side of the second groove is D1, and the diameter of the breathable membrane is D2, satisfying: 1<D1 / D2≤2, optionally, 1.1≤D1 / D2≤1.5.

[0017] In the above technical solution, when D1 / D2≤2, the distance between the outer peripheral surface of the breathable membrane and the side of the second groove is not too large, resulting in a larger area of ​​the first region covering the first surface. The limiting member can press the larger area of ​​the first region against the first surface, which is beneficial to improving the support and limiting effect on the first region. This helps reduce the risk of wrinkles in the breathable membrane during the use of the battery cell, allowing the breathable membrane to stably cover the first vent hole, maintaining the breathability of the breathable membrane, and thus improving the reliability of the battery cell. In addition, when the limiting member is welded to the wall, the heat of welding may partially melt the first region. The flow space of the fluid after the first region melts is small, and the fluid after the first region melts can basically remain in its original position. As welding is completed and the temperature drops, the fluid in the first region melts and solidifies, returning to its original state. This allows the breathable membrane to stably cover the first vent hole, maintaining the breathability of the breathable membrane and thus improving the reliability of the battery cell.

[0018] When D1 / D2 > 1.1, the distance between the outer periphery of the vent membrane and the side of the second groove is larger, which can reduce the size of the vent membrane, lower its cost, and simplify assembly. When D1 / D2 ≤ 2, the area of ​​the first region covering the first surface is larger, and the limiting component can press the larger area of ​​the first region against the first surface, which is beneficial for improving the support and limiting effect of the first region. This helps reduce the risk of wrinkles in the vent membrane during battery cell use, allowing the vent membrane to stably cover the first vent hole, maintaining its permeability and thus improving the reliability of the battery cell. Furthermore, when the limiting component is welded to the wall, the heat from welding may partially melt the first region. The flow space of the melted fluid in the first region is small, and the melted fluid can basically remain in its original position. As welding is completed and the temperature drops, the melted fluid in the first region will solidify, returning to its original state. This allows the vent membrane to stably cover the first vent hole, maintaining its permeability and thus improving the reliability of the battery cell.

[0019] As an optional technical solution in this application embodiment, the battery cell includes a heat insulation component, which is disposed between the first surface and the limiting component and surrounds the breathable membrane.

[0020] In the above technical solution, the inclusion of a heat insulation component helps reduce the impact of external heat on the breathable membrane, maintains its breathability, and thus improves the reliability of the battery cell. When the limiting component is welded to the wall, the heat insulation component can, to some extent, prevent the heat from welding from being conducted to the breathable membrane, reducing the risk of the breathable membrane melting due to the heat of welding.

[0021] As an optional technical solution in this application embodiment, the limiting member has a second surface, the second surface is provided with a third groove, and the bottom wall of the third groove is provided with a second vent hole; the sealing member is at least partially accommodated in the third groove, a portion of the vent membrane is accommodated in the third groove and abuts between the sealing member and the bottom surface of the third groove, and the first area at least partially abuts between the wall and the second surface.

[0022] In the above technical solution, by setting a third groove on the limiting member, it is easy to accommodate the sealing member, so that the first area can at least partially abut against the wall and the second surface, so that the limiting member and the wall can cooperate to support and limit the first area, which helps to reduce the risk of wrinkles in the breathable membrane during the use of the battery cell, and allows the breathable membrane to stably cover the first vent, which helps to maintain the breathability of the breathable membrane and thus improve the reliability of the battery cell.

[0023] As an optional technical solution in this application embodiment, the wall portion is provided with a second groove, the limiting member is at least partially accommodated in the second groove, and the first area at least partially abuts between the bottom surface of the second groove and the second surface.

[0024] In the above technical solution, by providing a second groove on the wall and having the limiting member at least partially accommodated in the second groove, the height of the limiting member protruding from the outer or inner surface of the wall is reduced, thereby reducing the risk of interference between the limiting member and other components.

[0025] As an optional technical solution in this application embodiment, the limiting member is welded to the wall portion.

[0026] In the above technical solution, the limiting component is welded to the wall, resulting in high connection strength and good connection stability between the limiting component and the wall. During the welding of the limiting component to the wall, the heat from the welding may partially melt the first zone. Even after melting, the first zone remains confined between the limiting component and the wall. As welding completes and the temperature drops, the molten fluid in the first zone solidifies, returning to its original state. This allows the permeable membrane to stably cover the first vent, maintaining the permeability of the membrane and thus improving the reliability of the battery cell.

[0027] As an optional technical solution in this application embodiment, the limiting member is welded to the wall to form a weld mark. In the projection plane perpendicular to the thickness direction of the wall, the minimum distance between the orthographic projection of the weld mark and the orthographic projection of the sealing member is L, which satisfies: L≥2mm, and optionally, L≥3mm.

[0028] In the above technical solution, when L≥2mm, the minimum distance between the orthographic projection of the welded portion in the projection plane perpendicular to the thickness direction of the wall and the orthographic projection of the seal in the projection plane perpendicular to the thickness direction of the wall is relatively large. This means the heat from welding is less likely to cause the portion of the permeable membrane located between the seal and the limiting member to melt, allowing the permeable membrane to stably cover the first vent hole. This helps maintain the permeability of the permeable membrane, thereby improving the reliability of the battery cell. Furthermore, the heat from welding is less likely to affect the seal, thus helping to maintain the sealing performance of the seal.

[0029] When L≥3mm, the minimum distance between the orthographic projection of the weldment in the plane perpendicular to the thickness direction of the wall and the orthographic projection of the seal in the same plane is larger. This makes it less likely that the heat from welding will cause the portion of the vent membrane located between the seal and the limiting member to melt, allowing the vent membrane to stably cover the first vent hole. This helps maintain the vent membrane's permeability and thus improves the reliability of the battery cell. Furthermore, the heat from welding is less likely to affect the seal, thus helping to maintain its sealing performance.

[0030] As an optional technical solution in this application embodiment, the first vent is connected to the internal space of the outer shell; along the thickness direction of the wall portion, the wall portion has an outer surface, and the limiting member is welded to the wall portion to form a weld mark portion, the weld mark portion not protruding from the outer surface.

[0031] In the above technical solution, by ensuring that the solder mark does not protrude from the outer surface of the wall, it is beneficial to reduce the risk of interference between the solder mark and other components.

[0032] As an optional technical solution in this application embodiment, the outer surface is provided with a fourth groove, and the solder mark is at least partially accommodated in the fourth groove.

[0033] In the above technical solution, by providing a fourth groove on the outer surface and at least partially accommodating the solder mark within the fourth groove, the solder mark does not protrude from the outer surface of the wall, resulting in a simple structure that is easy to manufacture.

[0034] As an optional technical solution in this application embodiment, the vent valve further includes a support member, the support member being a breathable material, the support member covering the second vent hole, and along the thickness direction of the wall portion, the support member being located between the second vent hole and the breathable membrane, with the breathable membrane abutting against the support member.

[0035] In the above technical solution, the support component can support the breathable membrane, making the breathable membrane less prone to deformation, which is beneficial to improving the breathability of the breathable membrane and enhancing the reliability of the battery cell.

[0036] As an optional technical solution in this application embodiment, the limiting member has a third surface, the third surface is provided with a fifth groove, the second vent hole is provided on the bottom wall of the fifth groove, and the support member is at least partially accommodated in the fifth groove.

[0037] In the above technical solution, by providing a fifth groove on the third surface, the support member can be at least partially accommodated within the fifth groove. This helps to reduce the height of the support member protruding from the third surface, improves the flatness of the breathable membrane, reduces the risk of tearing and deformation of the breathable membrane, and maintains the breathability of the breathable membrane, thereby improving the reliability of the battery cell. Furthermore, by providing the fifth groove, the dimensions of the breathable valve in the thickness direction of the wall can be reduced, thus reducing the volume occupied by the breathable valve and improving the energy density of the battery cell.

[0038] As an optional technical solution in this application embodiment, the surface of the support member facing the breathable membrane is flush with the third surface.

[0039] In the above technical solution, by making the surface of the support member facing the breathable membrane and the third surface flush, the breathable membrane is made relatively flat, which helps to reduce the risk of the breathable membrane being stretched and deformed, helps to maintain the breathability of the breathable membrane, and thus improves the reliability of the battery cell.

[0040] As an optional technical solution in this application embodiment, in a projection plane perpendicular to the thickness direction of the wall, the orthographic projection of the seal is arranged around the orthographic projection of the support.

[0041] In the above technical solution, by setting the orthogonal projection of the sealing element in the projection plane perpendicular to the thickness direction of the wall around the orthogonal projection of the support element in the projection plane perpendicular to the thickness direction of the wall, the sealing element can abut against the limiting element through the breathable membrane, thereby achieving a better sealing effect.

[0042] As an optional technical solution in this application embodiment, a boss is provided on the wall, the boss is arranged around the first vent hole, and the sealing member is sleeved on the boss.

[0043] In the above technical solution, by setting a boss on the wall and fitting the seal onto the boss, it is beneficial to position the seal and simplify the assembly.

[0044] As an optional technical solution in this application embodiment, the battery cell includes a pressure relief mechanism disposed on the wall portion. The pressure relief mechanism includes a weak portion, which is configured to be at least partially damaged when the internal pressure of the battery cell reaches a threshold.

[0045] In the above technical solution, by setting up a pressure relief mechanism, the mechanism can at least partially open to relieve pressure when the internal pressure inside the battery cell reaches a threshold, which helps reduce the risk of battery cell fire and explosion and improves the reliability of the battery cell. Furthermore, both the pressure relief mechanism and the vent valve are located on the wall, so in the event of thermal runaway of the battery cell, the pressure relief mechanism and the vent valve can release pressure in one direction, thereby protecting electrical connection components located in other directions.

[0046] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, the electrode assembly is housed in the housing, the wall portion is located at the bottom of the electrode assembly, and the wall portion supports the electrode assembly.

[0047] In the above technical solution, the wall supports the electrode assembly, and the wall is located at the bottom of the battery cell. When the battery cell experiences thermal runaway, the vent valve fails, and the emissions inside the battery cell can be ejected from the vent valve, that is, from the bottom of the battery cell. This helps to reduce the risk of personal injury caused by the emissions and improve the reliability of the battery cell.

[0048] As an optional technical solution in this application embodiment, the outer shell includes a housing and an end cap. The housing includes an integrally formed bottom wall and a side wall. The side wall surrounds the bottom wall, and one end of the side wall away from the bottom wall forms an opening. The end cap closes the opening. The bottom wall is the wall portion.

[0049] In the above technical solution, the bottom wall is the wall portion. When the battery cell experiences thermal runaway, the vent valve fails, and the emissions inside the battery cell can be ejected from the vent valve, that is, from the bottom of the battery cell. This helps to reduce the risk of personal injury caused by the emissions and improve the reliability of the battery cell.

[0050] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly housed within the casing; the electrode assembly includes a positive electrode sheet, the positive electrode sheet includes a positive electrode active material capable of reversibly extracting and inserting metal ions, the positive electrode active material includes a nickel-containing compound; the nickel-containing compound includes a layered lithium-containing transition metal oxide, wherein the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; optionally, the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0051] In the above technical solution, by ensuring that the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the energy density and cycle life of the battery cell can be effectively improved. Furthermore, when the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the battery cell produces more gas, thus requiring a vent valve.

[0052] By ensuring that the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the energy density and cycle life of the battery cell can be further improved. When the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the battery cell produces more gas, thus requiring a vent valve.

[0053] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, which is housed within the outer casing; the electrode assembly includes a negative electrode sheet, which includes a negative electrode active material, which includes elemental sodium metal.

[0054] In the above technical solution, the negative electrode active material includes elemental sodium metal, so the battery cell is a sodium-ion battery cell. Sodium-ion battery cells produce more gas, so a vent valve is more necessary.

[0055] As an optional technical solution in this application embodiment, the base metal of the outer shell is iron or titanium.

[0056] In the above technical solution, the base metal of the outer casing is iron or titanium, and the thickness of the outer casing can be manufactured to be smaller, which is beneficial to improving the energy density of the battery cell. Due to the smaller thickness of the outer casing, it is more likely to expand outward under the internal air pressure of the battery cell, which can easily lead to fatigue failure. Therefore, it is more necessary to set up a vent valve.

[0057] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0058] Thirdly, embodiments of this application also provide an electrical device, which includes the aforementioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0061] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0062] Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0063] Figure 4 Exploded views of a single battery cell provided in some embodiments of this application;

[0064] Figure 5 Schematic diagrams of the housing structure provided for some embodiments of this application;

[0065] Figure 6 This is a cross-sectional view of the connection between the vent valve and the wall provided in some embodiments of this application;

[0066] Figure 7 Cross-sectional views of the wall portion provided for some embodiments of this application;

[0067] Figure 8 A cross-sectional view showing the connection between the vent valve and the wall in some other embodiments of this application;

[0068] Figure 9 Cross-sectional views of the wall portion provided for other embodiments of this application;

[0069] Figure 10 A cross-sectional view of the connection between the vent valve and the wall provided in some embodiments of this application;

[0070] Figure 11 A cross-sectional view of the connection between the vent valve and the wall provided in some embodiments of this application;

[0071] Figure 12 This application also provides cross-sectional views of the connection between the vent valve and the wall in some embodiments;

[0072] Figure 13 This application also provides cross-sectional views of the wall portion in some embodiments;

[0073] Figure 14 This application also includes cross-sectional views of the limiting member provided in some embodiments;

[0074] Figure 15 A cross-sectional view showing the connection between the vent valve and the wall in some other embodiments of this application;

[0075] Figure 16 A cross-sectional view of the wall portion provided for some other embodiments of this application.

[0076] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Battery cell; 21-Outer shell; 211-Shell; 2111-Side wall; 2112-Bottom wall; 212-End cap; 213-Wall; 2131-First vent; 2132-First groove; 2133-Second groove; 21331-First surface; 2134-Fourth groove; 2135-Outer surface; 2136-Boss; 22-Electrode assembly; 221-Main body; 222-Electrode... Ear; 23-vent valve; 231-limiting element; 2311-second vent hole; 2312-second surface; 2313-third groove; 2314-fifth groove; 232-vent membrane; 2321-first zone; 233-support element; 234-welding part; 24-seal element; 25-electrode terminal; 26-pressure relief mechanism; 261-weak part; 27-insulating element; 28-heat insulation element; 100-battery device; 200-controller; 300-motor; 1000-vehicle. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0079] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0080] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0082] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0083] In this application, "multiple" means two or more (including two).

[0084] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0085] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0086] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0087] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0088] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0089] As an example, the positive electrode current collector can be a foil or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can 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, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0090] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0091] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0092] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0093] As an example, the negative electrode current collector can be a foil, a foamed metal, or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, carbon electrodes, carbon, nickel, or titanium, etc. The foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0094] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0095] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0096] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0097] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0098] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0099] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0100] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0101] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0102] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0103] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0104] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0105] In some implementations, the electrode assembly is a stacked structure.

[0106] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0107] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0108] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0109] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0110] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0111] In some implementations, the electrode assembly may be flat or polygonal in shape.

[0112] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0113] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, or a composite metal (such as a copper-aluminum composite housing).

[0114] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0115] As an example, a battery cell can be a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0116] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0117] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0118] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0119] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cell assemblies housed within the housing.

[0120] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0121] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0122] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0123] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0124] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0125] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0126] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0127] The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery reliability must also be considered. However, current battery reliability is relatively poor.

[0128] To improve the reliability of individual battery cells, a vent valve can be installed. This vent valve includes a limiting component and a vent membrane. The limiting component is connected to the outer casing and presses the vent membrane against the casing. However, defects in the connection between the limiting component and the outer casing can easily lead to electrolyte leakage and allow external impurities to enter the battery cell, resulting in poor battery cell reliability.

[0129] If a seal is directly installed between the breathable membrane and the outer shell, the portion of the breathable membrane extending beyond the outer periphery of the seal will not be supported. During use, wrinkles may easily appear, pulling on the portion of the breathable membrane that covers the vent holes of the outer shell and affecting the breathability of the membrane.

[0130] Therefore, this application provides a battery cell, which includes a casing, a vent valve, and a seal. The casing has a wall portion with a first vent hole. The vent valve includes a limiting member and a vent membrane. The limiting member is connected to the wall portion and has a second vent hole corresponding to the first vent hole. Along the thickness direction of the wall portion, the first and second vent holes are located on opposite sides of the vent membrane. The seal is disposed around the first vent hole and at least partially abuts against the vent membrane and the wall portion. The vent membrane includes a first region. In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the first region surrounds the orthographic projection of the seal, and the first region at least partially abuts against the limiting member and the wall portion.

[0131] The battery cell is equipped with a vent valve. When the internal pressure of the battery cell increases, the vent valve allows gas to be released from the inside of the battery cell, thereby reducing the internal pressure and improving the reliability of the battery cell. Since the vent membrane prevents liquid from passing through, a seal is placed between the vent membrane and the wall to seal both, reducing the risk of electrolyte leakage and the risk of external impurities entering the battery cell, thus improving the reliability of the battery cell. By ensuring that the first region at least partially abuts against the limiting member and the wall, the limiting member and the wall cooperate to support and limit the first region, reducing the risk of wrinkles appearing in the vent membrane during battery cell use. This allows the vent membrane to stably cover the first vent hole, maintaining the vent membrane's permeability and further improving the reliability of the battery cell. In addition, when the limiting member is welded to the wall, the heat of welding may cause the first area to partially melt. After the first area melts, it is still confined between the limiting member and the wall. As the welding is completed and the temperature drops, the molten fluid in the first area will solidify and return to its original state, so that the breathable membrane can stably cover the first vent. This helps to maintain the breathability of the breathable membrane and thus improve the reliability of the battery cell.

[0132] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0133] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0134] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0135] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0136] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0137] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and battery cells 20, the housing 10 being used to house the battery cells 20.

[0138] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which are interlocked. The first housing body 11 and the second housing body 12 can have various shapes, such as cuboids or cylinders. The first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can also be a hollow structure open on one side. The open side of the second housing body 12 interlocks with the open side of the first housing body 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can be a plate-like structure, with the second housing body 12 interlocked with the open side of the first housing body 11, thus forming a housing 10 with an accommodating chamber.

[0139] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0140] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0141] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , Figure 3 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a schematic diagram of the structure of the housing 211 provided in some embodiments of this application. Figure 6This is a cross-sectional view showing the connection between the vent valve 23 and the wall portion 213 in some embodiments of this application. Figure 7 This is a cross-sectional view of the wall portion 213 provided in some embodiments of this application. Embodiments of this application provide a battery cell 20, which includes a housing 21, a vent valve 23, and a seal 24. The housing 21 has a wall portion 213, which has a first vent hole 2131. The vent valve 23 includes a limiting member 231 and a vent membrane 232. The limiting member 231 is connected to the wall portion 213 and has a second vent hole 2311, which corresponds to the first vent hole 2131. Along the thickness direction of the wall portion 213, the first vent hole 2131 and the second vent hole 2311 are located on opposite sides of the vent membrane 232. The seal 24 surrounds the first vent hole 2131 and at least partially abuts against the vent membrane 232 and the wall portion 213. The breathable membrane 232 includes a first region 2321. In a projection plane perpendicular to the thickness direction of the wall portion 213, the orthographic projection of the first region 2321 surrounds the orthographic projection of the seal 24. The first region 2321 at least partially abuts between the limiting member 231 and the wall portion 213.

[0142] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0143] The housing 21 includes a housing 211 and an end cap 212. The housing 211 has a receiving space with an opening at one end for accommodating the electrode assembly 22. The end cap 212 is connected to the housing 211 and closes the opening.

[0144] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 212 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. The material of end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. End cap 212 is also provided with electrode terminals 25, which are used for electrical connection with the tabs 222 of electrode assembly 22 to input or output electrical energy of battery cell 20. Electrode terminals 25 and tabs 222 can be directly connected, for example, by direct welding of electrode terminals 25 to tabs 222. The electrode terminal 25 and the tab 222 can also be indirectly connected, for example, through a current collector. The battery cell 20 also includes an insulator 27 disposed inside the end cap 212. The insulator 27 can be used to isolate the electrical connection components within the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulator 27 can be made of plastic, rubber, etc.

[0145] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0146] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 221 of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute tabs 222. The positive and negative tabs may be located together at one end of the main body 221 or separately at both ends of the main body 221. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte.

[0147] The wall portion 213 can be an end cap 212 of the outer casing 21, or it can be a wall of the housing 211 of the outer casing 21. For example, in... Figure 3 and Figure 4 In some embodiments, wall portion 213 is an end cap 212. In other embodiments, wall portion 213 is a bottom wall 2112 of housing 211 disposed opposite to end cap 212. In still other embodiments, housing 211 includes side walls 2111, and wall portion 213 is a wall of side wall 2111.

[0148] Please refer to Figure 6 The thickness direction of the wall portion 213 is the X direction shown in the figure.

[0149] The first vent 2131 is a through hole provided in the wall portion 213, and the first vent 2131 penetrates two opposing surfaces of the wall portion 213 along the thickness direction of the wall portion 213. The shape of the first vent 2131 can be circular, square, elliptical, etc. The wall portion 213 can be provided with one or more first vent holes 2131.

[0150] The limiting member 231 is the part of the vent valve 23 that connects to the wall portion 213. The limiting member 231 can be welded to the wall portion 213 or bonded to it. The limiting member 231 is provided with a second vent hole 2311, which is a through hole extending through two opposing surfaces of the limiting member 231 along the thickness direction of the wall portion 213. The shape of the second vent hole 2311 can be circular, square, elliptical, etc. The limiting member 231 can have one or more second vent holes 2311.

[0151] "The second vent 2311 is configured to correspond to the first vent 2131" means that in a projection plane perpendicular to the thickness direction of the wall portion 213, the projection of the hole wall surface of the second vent 2311 at least partially overlaps with the projection of the hole wall surface of the first vent 2131. Optionally, the first vent 2131 and the second vent 2311 are coaxially configured.

[0152] The first vent 2131 and the second vent 2311 are located on both sides of the breathable membrane 232 along the thickness direction of the wall portion 213. Since the breathable membrane 232 can permeate gas, gas can pass through the breathable membrane 232 from the first vent 2131 and enter the second vent 2311, or pass through the breathable membrane 232 from the second vent 2311 and enter the first vent 2131.

[0153] The breathable membrane 232 is a core component of the breathable valve 23. When gas is generated in the battery cell 20, causing the internal pressure of the battery cell 20 to increase, the breathable membrane 232 expands elastically under pressure, creating gaps and forming an exhaust channel. The breathable membrane 232 has the properties of being breathable but impermeable to water. The material of the breathable membrane 232 can be a porous structure with a pore size between 0.1 and 10 μm. At this size, air molecules can pass through freely, while water molecules and large molecules such as dust impurities cannot pass through. The material of the breathable membrane 232 can be a polymer material, such as polytetrafluoroethylene or polypropylene.

[0154] The sealing element 24 is an annular structure surrounding the first vent hole 2131. The sealing element 24 can partially or completely abut against the vent membrane 232 and the wall portion 213 to seal the vent membrane 232 and the wall portion 213. The sealing element 24 is a structure capable of achieving a sealing function, such as sealant, gasket, sealing sheet, sealing ring, etc.

[0155] The first zone 2321 is the portion of the breathable membrane 232 that extends beyond the outer peripheral surface of the sealing ring. The orthographic projection of the first zone 2321 in a projection plane perpendicular to the thickness direction of the wall portion 213 surrounds the orthographic projection of the sealing member 24 in a projection plane perpendicular to the thickness direction of the wall portion 213. The limiting member 231 presses part or all of the first zone 2321 against the wall portion 213, thereby providing support and limiting for the first zone 2321.

[0156] The battery cell 20 is equipped with a vent valve 23. When the internal air pressure of the battery cell 20 increases, the vent valve 23 allows gas to be released from the inside of the battery cell 20, thereby reducing the internal pressure of the battery cell 20 and improving its reliability. Since the vent membrane 232 can prevent liquid from passing through, a seal 24 is provided between the vent membrane 232 and the wall portion 213 to seal the vent membrane 232 and the wall portion 213, reducing the risk of electrolyte leakage and the risk of impurities from outside the battery cell 20 entering the battery cell 20, which is beneficial to improving the reliability of the battery cell 20. By ensuring that the first region 2321 at least partially abuts against the limiting member 231 and the wall portion 213, the limiting member 231 and the wall portion 213 can cooperate to support and limit the first region 2321. This helps reduce the risk of wrinkles appearing in the venting membrane 232 during the use of the battery cell 20, allowing the venting membrane 232 to stably cover the first vent hole 2131, thus maintaining the permeability of the venting membrane 232 and improving the reliability of the battery cell 20. Furthermore, when the limiting member 231 is welded to the wall portion 213, the heat from the welding may partially melt the first region 2321. Even after melting, the first region 2321 remains confined between the limiting member 231 and the wall portion 213. As the welding is completed and the temperature drops, the molten fluid in the first region 2321 will solidify, returning to its original state. This allows the venting membrane 232 to stably cover the first vent hole 2131, maintaining the permeability of the venting membrane 232 and improving the reliability of the battery cell 20.

[0157] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the wall portion 213 has a first surface 21331, the first surface 21331 is provided with a first groove 2132, and the bottom wall of the first groove 2132 is provided with a first vent hole 2131. The sealing member 24 is at least partially accommodated in the first groove 2132, and the sealing member 24 abuts between the vent membrane 232 and the bottom surface of the first groove 2132. The vent membrane 232 covers the first groove 2132, and the first region 2321 at least partially abuts between the limiting member 231 and the first surface 21331.

[0158] The first surface 21331 can be the outer surface 2135 of the wall portion 213, or the inner surface of the wall portion 213. The first surface 21331 can also be a surface located between the outer surface 2135 and the inner surface of the wall portion 213 along the thickness direction of the wall portion 213.

[0159] The first groove 2132 is a groove body disposed on the first surface 21331, and the groove opening of the first groove 2132 is located on the first surface 21331. The first vent hole 2131 is disposed on the bottom wall of the first groove 2132.

[0160] The seal 24 is partially or entirely accommodated in the first groove 2132, and the seal 24 abuts against the bottom surface of the vent membrane 232 and the first groove 2132. In other words, the limiting member 231 presses the seal 24 against the bottom surface of the first groove 2132 through the vent membrane 232, so that the seal 24 can seal the vent membrane 232 and the bottom surface of the first groove 2132.

[0161] The limiting member 231 presses part or all of the first area 2321 against the first surface 21331 of the wall portion 213, thereby providing support and limiting for the first area 2321.

[0162] By providing a first groove 2132 on the first surface 21331, the sealing member 24 is easily accommodated, reducing the height of the sealing member 24 protruding from the first surface 21331. This allows the breathable membrane 232 to be relatively flatly positioned between the limiting member 231 and the wall portion 213, reducing the risk of the breathable membrane 232 being stretched and deformed, maintaining its breathability, and thus improving the reliability of the battery cell 20. By having the first region 2321 at least partially abut against the limiting member 231 and the first surface 21331, the limiting member 231 and the wall portion 213 can cooperate to support and limit the first region 2321. This reduces the risk of wrinkles appearing in the breathable membrane 232 during the use of the battery cell 20, allowing the breathable membrane 232 to stably cover the first vent 2131, maintaining its breathability, and thus improving the reliability of the battery cell 20.

[0163] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, along the thickness direction of the wall portion 213, the surface of the seal 24 facing the breathable membrane 232 is flush with the first surface 21331.

[0164] The surface of the seal 24 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is flush with the first surface 21331, that is, the surface of the seal 24 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is in the same plane as the first surface 21331.

[0165] It should be noted that, due to manufacturing errors, when the distance between the surface of the seal 24 facing the breathable membrane 232 and the first surface 21331 along the thickness direction of the wall portion 213 is less than or equal to 0.5 mm, it should be considered that the surface of the seal 24 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is flush with the first surface 21331.

[0166] By making the surface of the seal 24 facing the breathable membrane 232 along the thickness direction of the wall 213 flush with the first surface 21331, the breathable membrane 232 can be more evenly disposed between the limiting member 231 and the wall 213, which is more conducive to reducing the risk of the breathable membrane 232 being stretched and deformed, and more conducive to maintaining the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20.

[0167] Please refer to Figure 8 and Figure 9 , Figure 8 A cross-sectional view showing the connection between the vent valve 23 and the wall portion 213, provided in some other embodiments of this application. Figure 9 This is a cross-sectional view of the wall portion 213 provided in some other embodiments of this application. In some other embodiments, the wall portion 213 is provided with a second groove 2133, the bottom surface of the second groove 2133 is a first surface 21331, and the limiting member 231 is at least partially accommodated in the second groove 2133.

[0168] The second groove 2133 is a groove provided on the wall portion 213, and the bottom surface of the second groove 2133 is the first surface 21331. In other words, the first groove 2132 is provided on the bottom surface of the second groove 2133. The limiting member 231 can be partially or completely accommodated in the second groove 2133.

[0169] By providing a second groove 2133 on the wall portion 213 and having the limiting member 231 at least partially accommodated within the second groove 2133, the height of the limiting member 231 protruding from the outer surface 2135 or inner surface of the wall portion 213 is reduced, thereby reducing the risk of interference between the limiting member 231 and other components.

[0170] Please refer to Figure 8 and Figure 9 In some embodiments, the first region 2321 is fully abutted between the limiting member 231 and the first surface 21331, and the first region 2321 completely covers the first surface 21331.

[0171] The limiting member 231 presses the entire first area 2321 against the first surface 21331 of the wall portion 213, so as to provide better support and limiting for the first area 2321.

[0172] The first region 2321 completely covers the bottom surface of the second groove 2133, and the first region 2321 extends to the side surface of the second groove 2133.

[0173] By ensuring that the first region 2321 completely covers the first surface 21331, and given the large area of ​​the first region 2321, the limiting member 231 can press the larger area of ​​the first region 2321 against the first surface 21331. This improves the support and limiting effect on the first region 2321, reduces the risk of wrinkles appearing on the breathable membrane 232 during the use of the battery cell 20, and allows the breathable membrane 232 to stably cover the first vent 2131, thus maintaining the breathability of the breathable membrane 232 and improving the reliability of the battery cell 20. In addition, when the limiting member 231 is welded to the wall portion 213, the heat of welding may cause the first region 2321 to partially melt. Since the first region 2321 completely covers the first surface 21331, the fluid after the first region 2321 melts has no space to flow and can remain in its original position. As welding is completed and the temperature drops, the fluid after the first region 2321 melts will solidify and return to its original state, so that the breathable membrane 232 can stably cover the first vent 2131, which is beneficial to maintaining the breathability of the breathable membrane 232 and thus improving the reliability of the battery cell 20.

[0174] Please refer to Figure 10 , Figure 10 This is a cross-sectional view showing the connection between the vent valve 23 and the wall portion 213 according to some embodiments of this application. In some embodiments, the first region 2321 is completely abutted between the limiting member 231 and the first surface 21331, and there is a distance between the outer peripheral surface of the vent membrane 232 and the groove side surface of the second groove 2133.

[0175] The limiting member 231 presses the entire first region 2321 against the first surface 21331 of the wall portion 213, thereby providing good support and limiting for the first region 2321. There is a distance between the outer peripheral surface of the breathable membrane 232 and the side surface of the second groove 2133, that is, a gap is provided between the breathable membrane 232 and the side surface of the second groove 2133, so the first region 2321 does not completely cover the first surface 21331.

[0176] By creating a distance between the outer peripheral surface of the breathable membrane 232 and the side surface of the second groove 2133, the size of the breathable membrane 232 can be reduced, thus lowering its cost. Furthermore, this also helps to reduce assembly difficulty.

[0177] Please refer to Figure 10In some embodiments, the orthographic projection of the outer peripheral surface of the breathable membrane 232 along the thickness direction of the wall portion 213 is circular, and the orthographic projection of the groove side surface of the second groove 2133 is circular. The diameter of the groove side surface of the second groove 2133 is D1, and the diameter of the breathable membrane 232 is D2, satisfying: 1 < D1 / D2 ≤ 2.

[0178] The outer peripheral surface of the breathable membrane 232 is circular when projected along the thickness direction of the wall portion 213, that is, the breathable membrane 232 is a circular membrane.

[0179] The side of the second groove 2133 is circular when projected along the thickness direction of the wall 213, that is, the second groove 2133 is a circular groove.

[0180] D1 is the diameter of the side surface of the second groove 2133. During measurement, multiple measurements can be taken and the average value can be used as D1.

[0181] D2 is the diameter of the breathable membrane 232. During measurement, multiple measurements can be taken and the average value can be used as D2.

[0182] D1 / D2 represents the ratio of the diameter of the side of the second groove 2133 to the diameter of the breathable membrane 232.

[0183] D1 / D2 can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.

[0184] When D1 / D2≤2, the distance between the outer peripheral surface of the breathable membrane 232 and the side of the groove of the second groove 2133 is not too large, so that the area of ​​the first region 2321 covering the first surface 21331 is large. The limiting member 231 can press the larger area of ​​the first region 2321 against the first surface 21331, which is beneficial to improve the support and limiting effect of the first region 2321, and to reduce the risk of wrinkles in the breathable membrane 232 during the use of the battery cell 20. This allows the breathable membrane 232 to stably cover the first vent 2131, which is beneficial to maintain the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20. In addition, when the limiting member 231 is welded to the wall portion 213, the heat of welding may cause the first region 2321 to partially melt. The flow space of the fluid after the first region 2321 melts is small, and the fluid after the first region 2321 melts can basically remain in its original position. As the welding is completed and the temperature drops, the fluid in the first region 2321 melts and solidifies, returning to its original state. This allows the breathable membrane 232 to stably cover the first vent 2131, which is beneficial to maintaining the breathability of the breathable membrane 232 and thus improving the reliability of the battery cell 20.

[0185] Optionally, 1.1 ≤ D1 / D2 ≤ 1.5.

[0186] D1 / D2 can be 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc.

[0187] When D1 / D2 > 1.1, the distance between the outer peripheral surface of the breathable membrane 232 and the side surface of the second groove 2133 is larger, which can reduce the size of the breathable membrane 232, reduce its cost, and simplify assembly. When D1 / D2 ≤ 2, the area of ​​the first region 2321 covering the first surface 21331 is larger, and the limiting member 231 can press the larger area of ​​the first region 2321 against the first surface 21331, which helps to improve the support and limiting effect on the first region 2321, reduces the risk of wrinkles in the breathable membrane 232 during the use of the battery cell 20, and allows the breathable membrane 232 to stably cover the first vent 2131, which helps to maintain the breathability of the breathable membrane 232 and thus improves the reliability of the battery cell 20. In addition, when the limiting member 231 is welded to the wall portion 213, the heat of welding may cause the first region 2321 to partially melt. The flow space of the fluid after the first region 2321 melts is small, and the fluid after the first region 2321 melts can basically remain in its original position. As the welding is completed and the temperature drops, the fluid in the first region 2321 melts and solidifies, returning to its original state. This allows the breathable membrane 232 to stably cover the first vent 2131, which is beneficial to maintaining the breathability of the breathable membrane 232 and thus improving the reliability of the battery cell 20.

[0188] Please refer to Figure 11 , Figure 11 This is a cross-sectional view showing the connection between the vent valve 23 and the wall portion 213 in some embodiments of this application. In some embodiments, the battery cell 20 includes a heat insulation member 28 disposed between the first surface 21331 and the limiting member 231, and surrounding the vent membrane 232.

[0189] The thermal insulation component 28 has poor heat conduction performance, meaning its thermal conductivity is low. The thermal insulation component 28 can, to a certain extent, prevent external heat from being conducted to the breathable membrane 232, thereby reducing the risk of external heat damaging the breathable membrane 232. The thermal insulation component 28 can be made of polyimide, ceramic, aerogel, fiberglass, asbestos, rock wool, silicate, gel felt, vacuum board, polyurethane foam, extruded polystyrene, etc.

[0190] Optionally, the thermal conductivity of the insulation element 28 is less than or equal to 0.035 W / (m·K).

[0191] The heat insulation component 28 has a ring structure and is arranged around the outside of the breathable membrane 232. The limiting component 231 presses the heat insulation component 28 against the first surface 21331 of the wall portion 213 to limit the heat insulation component 28.

[0192] By incorporating the heat insulation component 28, the impact of external heat on the breathable membrane 232 is reduced, which helps maintain the breathability of the breathable membrane 232 and thus improves the reliability of the battery cell 20. When the limiting component 231 is welded to the wall portion 213, the heat insulation component 28 can, to a certain extent, prevent the heat from welding from being conducted to the breathable membrane 232, reducing the risk of the breathable membrane 232 melting due to the heat from welding.

[0193] Please refer to Figure 12 , Figure 13 and Figure 14 , Figure 12 A cross-sectional view showing the connection between the vent valve 23 and the wall portion 213 in some embodiments of this application. Figure 13 The present application also provides a cross-sectional view of the wall portion 213 according to some embodiments. Figure 14 The following is a cross-sectional view of the limiting member 231 provided in some embodiments of this application. In some embodiments, the limiting member 231 has a second surface 2312, the second surface 2312 is provided with a third groove 2313, and the bottom wall of the third groove 2313 is provided with a second vent hole 2311. The sealing member 24 is at least partially received in the third groove 2313, and a portion of the vent membrane 232 is received in the third groove 2313 and abuts against the bottom surface of the sealing member 24 and the third groove 2313. The first region 2321 at least partially abuts against the wall portion 213 and the second surface 2312.

[0194] The second surface 2312 can be the surface of the limiting member 231 closest to the inside of the outer shell 21, or the surface of the limiting member 231 furthest from the inside of the outer shell 21. Alternatively, the second surface 2312 can be the surface located along the thickness direction of the wall portion 213 between the surface of the limiting member 231 closest to the inside of the outer shell 21 and the surface of the limiting member 231 furthest from the inside of the outer shell 21.

[0195] The third groove 2313 is a groove body disposed on the second surface 2312, and the groove opening of the third groove 2313 is located on the second surface 2312. The second vent hole 2311 is disposed on the bottom wall of the second groove 2313.

[0196] The seal 24 is partially or entirely accommodated in the third groove 2313. A portion of the breathable membrane 232 is accommodated in the third groove 2313 and adheres to the bottom surface of the third groove 2313. The seal 24 abuts against the portion of the breathable membrane 232 that adheres to the bottom surface of the third groove 2313 and the wall portion 213. In other words, the bottom surface of the third groove 2313 presses the seal 24 against the wall portion 213 through the breathable membrane 232, so that the seal 24 can seal the breathable membrane 232 and the wall portion 213.

[0197] The limiting member 231 presses part or all of the first region 2321 against the wall portion 213, so that the first region 2321 at least partially abuts between the wall portion 213 and the second surface 2312, thereby providing support and limiting for the first region 2321.

[0198] By providing a third groove 2313 on the limiting member 231, it is easier to accommodate the sealing member 24, so that the first area 2321 can at least partially abut against the wall portion 213 and the second surface 2312. This allows the limiting member 231 and the wall portion 213 to cooperate in supporting and limiting the first area 2321, which helps reduce the risk of wrinkles appearing in the breathable membrane 232 during the use of the battery cell 20. It also allows the breathable membrane 232 to stably cover the first vent 2131, which helps maintain the breathability of the breathable membrane 232 and thus improves the reliability of the battery cell 20.

[0199] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the wall portion 213 is provided with a second groove 2133, and the limiting member 231 is at least partially accommodated within the second groove 2133. The first region 2321 at least partially abuts between the bottom surface of the second groove 2133 and the second surface 2312.

[0200] The second groove 2133 is a groove provided in the wall portion 213. The limiting member 231 can be partially or completely accommodated in the second groove 2133 to reduce the height of the limiting member 231 protruding from the outer surface 2135 or inner surface of the wall portion 213. The limiting member 231 presses part or all of the first area 2321 against the bottom surface of the second groove 2133, so that the first area 2321 is partially or completely abutted between the bottom surface of the second groove 2133 and the second surface 2312, thereby providing support and limiting for the first area 2321.

[0201] Please refer to Figure 12 , Figure 13 and Figure 14 In the embodiment shown in the figure, the first vent 2131 is disposed on the bottom wall of the second groove 2133.

[0202] By providing a second groove 2133 on the wall portion 213 and having the limiting member 231 at least partially accommodated within the second groove 2133, the height of the limiting member 231 protruding from the outer surface 2135 or inner surface of the wall portion 213 is reduced, thereby reducing the risk of interference between the limiting member 231 and other components.

[0203] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the limiting member 231 is welded to the wall portion 213.

[0204] In an embodiment where a second groove 2133 is provided in the wall portion 213 and the limiting member 231 is at least partially accommodated in the second groove 2133, the outer peripheral surface of the limiting member 231 and the groove side surface of the second groove 2133 are welded together.

[0205] The limiting member 231 is welded to the wall portion 213, resulting in a high connection strength and good connection stability between the limiting member 231 and the wall portion 213. When the limiting member 231 is welded to the wall portion 213, the heat of welding may cause partial melting of the first region 2321. After melting, the first region 2321 is still confined between the limiting member 231 and the wall portion 213. As welding is completed and the temperature drops, the molten fluid in the first region 2321 will solidify and return to its original state, allowing the venting membrane 232 to stably cover the first vent hole 2131. This helps maintain the venting performance of the venting membrane 232, thereby improving the reliability of the battery cell 20.

[0206] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the limiting member 231 is welded to the wall portion 213 to form a weld mark 234. In the projection plane perpendicular to the thickness direction of the wall portion 213, the minimum distance between the orthographic projection of the weld mark 234 and the orthographic projection of the seal 24 is L, which satisfies: L≥2mm.

[0207] The weld mark 234 is a weld formed by welding the limiting member 231 and the wall part 213.

[0208] L represents the minimum distance between the orthographic projection of the solder mark 234 in the projection plane perpendicular to the thickness direction of the wall portion 213 and the orthographic projection of the seal 24 in the projection plane perpendicular to the thickness direction of the wall portion 213.

[0209] L can be 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, etc.

[0210] When L≥2mm, the minimum distance between the orthographic projection of the solder mark 234 in the projection plane perpendicular to the thickness direction of the wall portion 213 and the orthographic projection of the seal 24 in the projection plane perpendicular to the thickness direction of the wall portion 213 is relatively large. This means the heat from welding is less likely to cause the portion of the vent membrane 232 located between the seal 24 and the limiting member 231 to melt, allowing the vent membrane 232 to stably cover the first vent hole 2131. This helps maintain the permeability of the vent membrane 232, thereby improving the reliability of the battery cell 20. Furthermore, the heat from welding is less likely to affect the seal 24, thus helping to maintain the sealing performance of the seal 24.

[0211] Optionally, L ≥ 3 mm.

[0212] L can be 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, etc.

[0213] When L≥3mm, the minimum distance between the orthographic projection of the solder mark 234 in the projection plane perpendicular to the thickness direction of the wall portion 213 and the orthographic projection of the seal 24 in the projection plane perpendicular to the thickness direction of the wall portion 213 is larger. This makes it less likely that the heat from welding will cause the portion of the vent membrane 232 located between the seal 24 and the limiting member 231 to melt. This allows the vent membrane 232 to stably cover the first vent hole 2131, which helps maintain the permeability of the vent membrane 232 and thus improves the reliability of the battery cell 20. Furthermore, the heat from welding is less likely to affect the seal 24, thus helping to maintain the sealing performance of the seal 24.

[0214] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the first vent 2131 communicates with the internal space of the outer casing 21. Along the thickness direction of the wall portion 213, the wall portion 213 has an outer surface 2135, and the limiting member 231 is welded to the wall portion 213 to form a solder mark 234, which does not protrude from the outer surface 2135.

[0215] The first vent 2131 is located on the side of the breathable membrane 232 facing the electrode assembly 22, and the second vent 2311 is located on the side of the breathable membrane 232 away from the electrode assembly 22. The first vent 2131 is closer to the electrode assembly 22 than the second vent 2311.

[0216] The wall portion 213 has an outer surface 2135, which is the surface of the wall portion 213 furthest from the interior of the outer shell 21 along its thickness direction.

[0217] The solder mark 234 does not extend beyond the outer surface 2135 of the wall portion 213 in the direction from the electrode assembly 22 toward the wall portion 213. This can be because the position of the solder mark 234 furthest from the electrode assembly 22 along the thickness direction of the wall portion 213 is flush with the outer surface 2135 of the wall portion 213, or the distance from the position of the solder mark 234 furthest from the electrode assembly 22 along the thickness direction of the wall portion 213 to the electrode assembly 22 is less than the distance from the outer surface 2135 of the wall portion 213 to the electrode assembly 22, so that the solder mark 234 is closer to the electrode assembly 22 than the outer surface 2135 of the wall portion 213.

[0218] By ensuring that the solder mark 234 does not protrude from the outer surface 2135 of the wall portion 213, it is beneficial to reduce the risk of the solder mark 234 interfering with other components.

[0219] In some embodiments, the outer surface 2135 is provided with a fourth groove 2134, and the solder stamp 234 is at least partially accommodated in the fourth groove 2134.

[0220] The fourth groove 2134 is a groove provided on the outer surface 2135 of the wall portion 213. The opening of the fourth groove 2134 is located on the first surface 21331. The fourth groove 2134 is recessed from the outer surface 2135 of the wall portion 213 toward the direction close to the electrode assembly 22.

[0221] Please refer to Figure 12 and Figure 13 In an embodiment where a second groove 2133 is provided in the wall portion 213 and the limiting member 231 is at least partially accommodated in the second groove 2133, the second groove 2133 is provided on the bottom surface of the fourth groove 2134.

[0222] In some embodiments, a portion of the solder mark 234 is accommodated in a fourth groove 2134, and another portion of the solder mark 234 is accommodated in a second groove 2133.

[0223] By providing a fourth groove 2134 on the outer surface 2135 and at least partially accommodating the solder mark 234 within the fourth groove 2134, the solder mark 234 does not protrude from the outer surface 2135 of the wall portion 213, resulting in a simple structure that is easy to manufacture.

[0224] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the vent valve 23 further includes a support member 233, which is made of a breathable material and covers the second vent hole 2311. Along the thickness direction of the wall portion 213, the support member 233 is located between the second vent hole 2311 and the breathable membrane 232, with the breathable membrane 232 abutting against the support member 233.

[0225] The support component 233 is a part of the vent valve 23 that supports the vent membrane 232, making the vent membrane 232 less prone to deformation. The support component 233 also possesses the properties of being breathable but impermeable to water. The breathability of the support component 233 can be better than that of the vent membrane 232, thereby reducing its impact on the breathability process of the vent membrane 232. The support component 233 can be made of a variety of materials, including expanded polytetrafluoroethylene (ePTFE), polypropylene, polyamide, polytetrafluoroethylene (PTFE), perfluoroethylene propylene (PFEP), and other porous polymers. It can also be a metal-organic framework porous material, as well as carbon film and ceramic porous materials.

[0226] The support member 233 can support the breathable membrane 232, making the breathable membrane 232 less prone to deformation, which is beneficial to improving the breathability of the breathable membrane 232 and improving the reliability of the battery cell 20.

[0227] Please refer to Figure 12 , Figure 13 and Figure 14 In some embodiments, the limiting member 231 has a third surface, on which a fifth groove 2314 is provided, and a second vent hole 2311 is provided on the bottom wall of the fifth groove 2314. The support member 233 is at least partially accommodated in the fifth groove 2314.

[0228] The third surface can be the surface of the limiting member 231 closest to the inside of the outer shell 21, or the surface of the limiting member 231 furthest from the inside of the outer shell 21. Alternatively, the third surface can be the surface located along the thickness direction of the wall portion 213 between the surface of the limiting member 231 closest to the inside of the outer shell 21 and the surface of the limiting member 231 furthest from the inside of the outer shell 21.

[0229] The fifth groove 2314 is a groove provided on the third surface, and the opening of the fifth groove 2314 is located on the third surface.

[0230] Please refer to Figure 12 , Figure 13 and Figure 14 In the embodiment where the limiting member 231 is provided with a third groove 2313, the third surface is the bottom surface of the third groove 2313, that is, the fifth groove 2314 is provided on the bottom surface of the third groove 2313. The bottom wall of the third groove 2313 includes the portion between the bottom surface of the third groove 2313 and the surface of the limiting member 231 opposite to the bottom surface of the third groove 2313, and the bottom wall of the fifth groove 2314. The second vent hole 2311 is provided on the bottom wall of the fifth groove 2314.

[0231] Please refer to Figure 15 and Figure 16 , Figure 15 This is a cross-sectional view showing the connection between the vent valve 23 and the wall portion 213, as provided in some other embodiments of this application. Figure 16 A cross-sectional view of the wall portion 213 provided for some other embodiments of this application. Figure 15 and Figure 16 In the embodiment shown, the third surface is the surface of the limiting member 231 that is closest to the electrode assembly 22 along the thickness direction of the wall portion 213.

[0232] The support member 233 can be partially or fully accommodated in the fifth groove 2314 to reduce the height of the support member 233 protruding from the third surface.

[0233] By providing a fifth groove 2314 on the third surface, the support member 233 is at least partially accommodated within the fifth groove 2314. This reduces the height of the support member 233 protruding from the third surface, improves the flatness of the breathable membrane 232, reduces the risk of stretching and deformation of the breathable membrane 232, and helps maintain the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20. Furthermore, by providing the fifth groove 2314, the dimension of the vent valve 23 in the thickness direction of the wall 213 is reduced, thus reducing the volume occupied by the vent valve 23 and improving the energy density of the battery cell 20.

[0234] Please refer to Figure 15 and Figure 16 In some embodiments, the surface of the support 233 facing the breathable membrane 232 is flush with the third surface.

[0235] The surface of the support member 233 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is flush with the third surface, that is, the surface of the support member 233 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is in the same plane as the third surface.

[0236] It should be noted that, due to manufacturing errors, when the distance between the surface of the support member 233 facing the breathable membrane 232 and the third surface along the thickness direction of the wall portion 213 is less than or equal to 0.5 mm, it should be considered that the surface of the support member 233 facing the breathable membrane 232 along the thickness direction of the wall portion 213 is flush with the third surface.

[0237] By making the surface of the support member 233 facing the breathable membrane 232 and the third surface flush, the breathable membrane 232 becomes relatively flat, which helps to reduce the risk of the breathable membrane 232 being stretched and deformed, and helps to maintain the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20.

[0238] Please refer to Figure 15 and Figure 16 In some embodiments, the orthographic projection of the seal 24 surrounds the orthographic projection of the support 233 in a projection plane perpendicular to the thickness direction of the wall 213.

[0239] "In the projection plane perpendicular to the thickness direction of the wall portion 213, the orthogonal projection of the seal 24 surrounds the orthogonal projection of the support 233." That is, the orthogonal projection of the seal 24 in the projection plane perpendicular to the thickness direction of the wall portion 213 surrounds the orthogonal projection of the support 233 in the projection plane perpendicular to the thickness direction of the wall portion 213.

[0240] By arranging the orthographic projection of the seal 24 in the projection plane perpendicular to the thickness direction of the wall portion 213 around the orthographic projection of the support member 233 in the projection plane perpendicular to the thickness direction of the wall portion 213, the seal 24 can abut against the limiting member 231 through the breathable membrane 232, thereby achieving a better sealing effect.

[0241] In some embodiments, a boss 2136 is provided on the wall portion 213, the boss 2136 is arranged around the first vent hole 2131, and the sealing member 24 is sleeved on the boss 2136.

[0242] Please refer to Figure 12 , Figure 13 and Figure 14 In the embodiment shown in the figure, the boss 2136 is an annular structure protruding from the bottom surface of the second groove 2133. The boss 2136 is arranged around the outer periphery of the first vent hole 2131, and the sealing member 24 is sleeved on the boss 2136.

[0243] Please refer to Figure 15 and Figure 16 In the embodiment shown in the figure, the boss 2136 is an annular structure protruding from the bottom surface of the first groove 2132. The boss 2136 is arranged around the outer periphery of the first vent hole 2131, and the sealing member 24 is sleeved on the boss 2136.

[0244] By providing a boss 2136 on the wall portion 213 and fitting the seal 24 onto the boss 2136, it is beneficial to position the seal 24 and simplify the assembly.

[0245] Please refer to this again. Figure 3 , Figure 4 and Figure 5 In some embodiments, the battery cell 20 includes a pressure relief mechanism 26 disposed on the wall portion 213. The pressure relief mechanism 26 includes a weak portion 261 configured to be at least partially destroyed when the internal pressure of the battery cell 20 reaches a threshold.

[0246] The pressure relief mechanism 26 is a component used to open when the internal pressure of the battery cell 20 reaches a threshold, thereby releasing the internal pressure of the battery cell 20. The pressure relief mechanism 26 can be a component mounted on the wall portion 213, in which case the pressure relief mechanism 26 is separately provided and connected to the wall portion 213. For example, the pressure relief mechanism 26 is an explosion-proof plate mounted on the wall portion 213. Alternatively, the pressure relief mechanism 26 can be part of the wall portion 213, in which case the pressure relief mechanism 26 is integrally formed with the wall portion 213.

[0247] The pressure relief mechanism 26 includes a weak section 261, which serves to relieve pressure. When the internal pressure of the battery cell 20 reaches a threshold, the pressure relief mechanism 26 can rupture along the weak section 261 to release the internal pressure of the battery cell 20. For example, when the internal pressure of the battery cell 20 reaches the explosion pressure, the weak section 261 ruptures under the action of the discharge (gas, electrolyte, etc.) inside the battery cell 20, allowing the discharge inside the battery cell 20 to be discharged smoothly.

[0248] The weak part 261 can be a ring structure, for example, the weak part 261 can be in the shape of a circular ring or an elliptical ring. The weak part 261 can also be a non-ring structure, for example, the weak part 261 can be C-shaped, U-shaped, etc.

[0249] By incorporating a pressure relief mechanism 26, the mechanism can at least partially open to release pressure when the internal pressure within the battery cell 20 reaches a threshold, thereby reducing the risk of fire and explosion of the battery cell 20 and improving its reliability. Furthermore, both the pressure relief mechanism 26 and the vent valve 23 are located on the wall 213. In the event of thermal runaway of the battery cell 20, the pressure relief mechanism 26 and the vent valve 23 can release pressure in one direction, thus protecting electrical connection components located in other directions.

[0250] Please refer to Figure 3 , Figure 4 and Figure 5 In some embodiments, the battery cell 20 includes an electrode assembly 22, which is housed in a housing 21. A wall portion 213 is located at the bottom of the electrode assembly 22 and supports the electrode assembly 22.

[0251] The wall portion 213 supports the electrode assembly 22. The wall portion 213 is located at the bottom of the battery cell 20. When the battery cell 20 experiences thermal runaway, the vent valve 23 fails, and the emissions inside the battery cell 20 can be ejected from the vent valve 23, that is, from the bottom of the battery cell 20. This helps to reduce the risk of personal injury caused by the emissions and improve the reliability of the battery cell 20.

[0252] Please refer to Figure 3 , Figure 4 and Figure 5 In some embodiments, the outer casing 21 includes a housing 211 and an end cap 212. The housing 211 includes an integrally formed bottom wall 2112 and a side wall 2111. The side wall 2111 surrounds the bottom wall 2112, and one end of the side wall 2111 away from the bottom wall 2112 forms an opening. The end cap 212 closes the opening. The bottom wall 2112 is a wall portion 213.

[0253] The housing 211 includes an integrally formed sidewall 2111 and a bottom wall 2112, meaning that the housing 211 is manufactured using an integral molding process, such as stamping, casting, or extrusion molding. In other words, the sidewall 2111 and bottom wall 2112 of the housing 211 are a single, integral structure. The sidewall 2111 has a cylindrical structure, with one end connected to the bottom wall 2112, and the other end of the sidewall 2111 forming an opening. An end cap 212 is connected to the sidewall 2111 and closes the opening.

[0254] The bottom wall 2112 is the wall 213. When the battery cell 20 experiences thermal runaway, the vent valve 23 fails, and the emissions inside the battery cell 20 can be ejected from the vent valve 23, that is, from the bottom of the battery cell 20. This helps to reduce the risk of personal injury caused by the emissions and improve the reliability of the battery cell 20.

[0255] In some embodiments, the battery cell 20 includes an electrode assembly 22 housed within a housing 21; the electrode assembly 22 includes a positive electrode sheet, the positive electrode sheet includes a positive active material capable of reversibly extracting and inserting metal ions, the positive active material includes a nickel-containing compound; the nickel-containing compound includes a layered lithium-containing transition metal oxide, wherein the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0256] By ensuring that the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the energy density and cycle life of the battery cell 20 can be effectively improved. However, when the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the battery cell 20 produces more gas, thus requiring a vent valve 23.

[0257] Optionally, the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0258] By ensuring that the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the energy density and cycle life of the battery cell 20 can be further improved. When the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide, the battery cell 20 produces more gas, thus requiring a more thorough gas vent valve 23.

[0259] In addition, it should be noted that for this high-nickel chemical system battery cell 20, in order to pursue high energy density, less electrolyte is injected, and there is basically no free electrolyte, so that when the vent valve 23 is located on the bottom wall 2112, the gas inside the battery cell 20 can be smoothly discharged.

[0260] In some embodiments, the battery cell 20 includes an electrode assembly 22, which is housed within a housing 21. The electrode assembly 22 includes a negative electrode sheet, which includes a negative electrode active material, and the negative electrode active material includes elemental sodium metal.

[0261] If the negative electrode active material includes elemental sodium metal, then the battery cell 20 is a sodium-ion battery cell 20. Sodium-ion battery cells 20 produce more gas, so a vent valve 23 is more necessary.

[0262] In some embodiments, the base metal of the housing 21 is iron or titanium.

[0263] "The base metal of the outer shell 21 is iron or titanium" means that the base metal of the outer shell 211 is iron or titanium, and the base metal of the end cap 212 is iron or titanium.

[0264] "The base metal of the shell 211 is iron" means that iron is the material with the highest mass percentage in the shell 211. For example, the material of the shell 211 can be carbon steel or stainless steel. Carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0265] "The base metal of the shell 211 is titanium" means that titanium is the material with the highest mass percentage in the shell 211. For example, the material of the shell 211 can be a titanium alloy.

[0266] "The base metal of end cap 212 is iron" means that iron is the material with the highest mass percentage in the end cap 212. For example, the material of end cap 212 can be carbon steel or stainless steel. Carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0267] "The base metal of end cap 212 is titanium" means that titanium is the material with the highest mass percentage in the end cap 212. For example, the material of end cap 212 can be a titanium alloy.

[0268] The base metal of the outer casing 21 is iron or titanium, and the thickness of the outer casing 21 can be made smaller, which is beneficial to improving the energy density of the battery cell 20. Because the outer casing 21 is thinner, it is more likely to expand outward under the internal air pressure of the battery cell 20, which can easily lead to fatigue failure. Therefore, it is necessary to set up a vent valve 23.

[0269] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0270] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0271] This application provides a battery cell 20, which includes a housing 21, a vent valve 23, and a sealing member 24. The housing 21 has a wall portion 213, and the wall portion 213 is provided with a first vent hole 2131. The vent valve 23 includes a limiting member 231 and a vent membrane 232. The limiting member 231 is connected to the wall portion 213 and is provided with a second vent hole 2311, which is corresponding to the first vent hole 2131. Along the thickness direction of the wall portion 213, the first vent hole 2131 and the second vent hole 2311 are respectively located on both sides of the vent membrane 232. The sealing member 24 is disposed around the first vent hole 2131 and at least partially abuts against the vent membrane 232 and the wall portion 213. The venting membrane 232 includes a first region 2321. In a projection plane perpendicular to the thickness direction of the wall portion 213, the orthographic projection of the first region 2321 surrounds the orthographic projection of the seal 24. The first region 2321 at least partially abuts against the limiting member 231 and the wall portion 213. The battery cell 20 is provided with a vent valve 23. When the internal air pressure of the battery cell 20 increases, the vent valve 23 allows gas to be released from the inside of the battery cell 20 to the outside, thereby reducing the internal pressure of the battery cell 20 and improving the reliability of the battery cell 20. Since the venting membrane 232 can prevent liquid from passing through, by providing a seal 24 between the venting membrane 232 and the wall portion 213 to seal the venting membrane 232 and the wall portion 213, the risk of electrolyte leakage is reduced, and the risk of impurities from outside the battery cell 20 entering the battery cell 20 is reduced, which is beneficial to improving the reliability of the battery cell 20. By ensuring that the first region 2321 at least partially abuts against the limiting member 231 and the wall portion 213, the limiting member 231 and the wall portion 213 can cooperate to support and limit the first region 2321. This helps reduce the risk of wrinkles appearing in the venting membrane 232 during the use of the battery cell 20, allowing the venting membrane 232 to stably cover the first vent hole 2131, thus maintaining the permeability of the venting membrane 232 and improving the reliability of the battery cell 20. Furthermore, when the limiting member 231 is welded to the wall portion 213, the heat from the welding may partially melt the first region 2321. Even after melting, the first region 2321 remains confined between the limiting member 231 and the wall portion 213. As the welding is completed and the temperature drops, the molten fluid in the first region 2321 will solidify, returning to its original state. This allows the venting membrane 232 to stably cover the first vent hole 2131, maintaining the permeability of the venting membrane 232 and improving the reliability of the battery cell 20.

[0272] The wall portion 213 has a first surface 21331, and a first groove 2132 is provided on the first surface 21331. A first vent hole 2131 is provided on the bottom wall of the first groove 2132. The sealing member 24 is at least partially accommodated in the first groove 2132, and the sealing member 24 abuts between the vent membrane 232 and the bottom surface of the first groove 2132. The vent membrane 232 covers the first groove 2132, and the first area 2321 at least partially abuts between the limiting member 231 and the first surface 21331. By providing the first groove 2132 on the first surface 21331, it is easier to accommodate the sealing member 24 and reduce the height of the sealing member 24 protruding from the first surface 21331. This allows the vent membrane 232 to be disposed relatively flat between the limiting member 231 and the wall portion 213, which helps to reduce the risk of the vent membrane 232 being stretched and deformed, helps to maintain the vent membrane 232's permeability, and thus improves the reliability of the battery cell 20. By having the first region 2321 at least partially abut against the limiting member 231 and the first surface 21331, the limiting member 231 and the wall portion 213 can cooperate to support and limit the first region 2321. This helps reduce the risk of wrinkles appearing in the breathable membrane 232 during the use of the battery cell 20, and allows the breathable membrane 232 to stably cover the first vent 2131, which helps maintain the breathability of the breathable membrane 232 and thus improves the reliability of the battery cell 20.

[0273] Along the thickness direction of the wall portion 213, the surface of the seal 24 facing the breathable membrane 232 is flush with the first surface 21331. By making the surface of the seal 24 facing the breathable membrane 232 along the thickness direction of the wall portion 213 flush with the first surface 21331, the breathable membrane 232 can be more evenly disposed between the limiting member 231 and the wall portion 213, which is more conducive to reducing the risk of the breathable membrane 232 being stretched and deformed, and more conducive to maintaining the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20.

[0274] The wall portion 213 is provided with a second groove 2133, the bottom surface of which is a first surface 21331. The limiting member 231 is at least partially accommodated within the second groove 2133. By providing the second groove 2133 on the wall portion 213 and ensuring that the limiting member 231 is at least partially accommodated within it, the height of the limiting member 231 protruding from the outer surface 2135 or inner surface of the wall portion 213 is reduced, thereby reducing the risk of interference between the limiting member 231 and other components.

[0275] The first region 2321 is completely abutted between the limiting member 231 and the first surface 21331, and the first region 2321 completely covers the first surface 21331. By making the first region 2321 completely cover the first surface 21331, the area of ​​the first region 2321 is relatively large. The limiting member 231 can press the larger area of ​​the first region 2321 against the first surface 21331, which is beneficial to improving the support and limiting effect of the first region 2321. This is beneficial to reducing the risk of wrinkles in the breathable membrane 232 during the use of the battery cell 20, so that the breathable membrane 232 can stably cover the first vent 2131, which is beneficial to maintaining the breathability of the breathable membrane 232, thereby improving the reliability of the battery cell 20. In addition, when the limiting member 231 is welded to the wall portion 213, the heat of welding may cause the first region 2321 to partially melt. Since the first region 2321 completely covers the first surface 21331, the fluid after the first region 2321 melts has no space to flow and can remain in its original position. As welding is completed and the temperature drops, the fluid after the first region 2321 melts will solidify and return to its original state, so that the breathable membrane 232 can stably cover the first vent 2131, which is beneficial to maintaining the breathability of the breathable membrane 232 and thus improving the reliability of the battery cell 20.

[0276] The first zone 2321 is entirely abutted between the limiting member 231 and the first surface 21331, and there is a distance between the outer peripheral surface of the breathable membrane 232 and the side surface of the second groove 2133. By creating a distance between the outer peripheral surface of the breathable membrane 232 and the side surface of the second groove 2133, on the one hand, the size of the breathable membrane 232 can be reduced, thus lowering its cost. On the other hand, it helps to reduce assembly difficulty.

[0277] The battery cell 20 includes a heat insulation element 28, which is disposed between the first surface 21331 and the limiting element 231, and surrounds the venting membrane 232. By providing the heat insulation element 28, the impact of external heat on the venting membrane 232 is reduced, which helps maintain the venting performance of the venting membrane 232, thereby improving the reliability of the battery cell 20. When the limiting element 231 is welded to the wall portion 213, the heat insulation element 28 can, to a certain extent, prevent the welding heat from being conducted to the venting membrane 232, reducing the risk of the venting membrane 232 melting due to the welding heat.

[0278] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The outer casing has a wall portion, wherein the wall portion is provided with a first vent hole; A breathable valve includes a limiting member and a breathable membrane. The limiting member is connected to the wall portion and is provided with a second breathable hole, which is provided corresponding to the first breathable hole. Along the thickness direction of the wall portion, the first breathable hole and the second breathable hole are respectively located on both sides of the breathable membrane. A sealing element is disposed around the first vent hole and at least partially abuts between the vent membrane and the wall portion. The vent membrane includes a first region, which, in a projection plane perpendicular to the thickness direction of the wall portion, has its orthographic projection surrounding the orthographic projection of the sealing element. The first region at least partially abuts between the limiting element and the wall portion.

2. The battery cell according to claim 1, characterized in that, The wall portion has a first surface, the first surface is provided with a first groove, and the bottom wall of the first groove is provided with the first vent hole. The seal is at least partially accommodated in the first groove, and the seal abuts between the breathable membrane and the bottom surface of the first groove. The breathable membrane covers the first groove, and the first area at least partially abuts between the limiting member and the first surface.

3. The battery cell according to claim 2, characterized in that, Along the thickness direction of the wall portion, the surface of the seal facing the breathable membrane is flush with the first surface.

4. The battery cell according to claim 2, characterized in that, The wall portion is provided with a second groove, the bottom surface of the second groove being the first surface, and the limiting member is at least partially accommodated within the second groove.

5. The battery cell according to claim 4, characterized in that, The first area is entirely abutted between the limiting member and the first surface, and the first area completely covers the first surface.

6. The battery cell according to claim 4, characterized in that, The first area is entirely abutted between the limiting member and the first surface, and there is a distance between the outer peripheral surface of the breathable membrane and the side surface of the second groove.

7. The battery cell according to claim 6, characterized in that, Along the thickness direction of the wall portion, the orthographic projection of the outer peripheral surface of the breathable membrane is circular, the orthographic projection of the groove side of the second groove is circular, the diameter of the groove side of the second groove is D1, and the diameter of the breathable membrane is D2, satisfying: 1<D1 / D2≤2, optionally, 1.1≤D1 / D2≤1.

5.

8. The battery cell according to claim 6, characterized in that, The battery cell includes a heat insulation component, which is disposed between the first surface and the limiting component and surrounds the breathable membrane.

9. The battery cell according to claim 1, characterized in that, The limiting member has a second surface, the second surface is provided with a third groove, and the bottom wall of the third groove is provided with a second vent hole; The seal is at least partially accommodated in the third groove, a portion of the breathable membrane is accommodated in the third groove and abuts between the seal and the bottom surface of the third groove, and the first region at least partially abuts between the wall and the second surface.

10. The battery cell according to claim 9, characterized in that, The wall portion is provided with a second groove, and the limiting member is at least partially accommodated in the second groove. The first area at least partially abuts between the bottom surface of the second groove and the second surface.

11. The battery cell according to any one of claims 1-10, characterized in that, The limiting member is welded to the wall portion.

12. The battery cell according to claim 11, characterized in that, The limiting member is welded to the wall to form a weld mark. In the projection plane perpendicular to the thickness direction of the wall, the minimum distance between the orthographic projection of the weld mark and the orthographic projection of the sealing member is L, which satisfies: L≥2mm, and optionally, L≥3mm.

13. The battery cell according to claim 11, characterized in that, The first vent is connected to the internal space of the outer shell; Along the thickness direction of the wall portion, the wall portion has an outer surface, and the limiting member is welded to the wall portion to form a weld mark portion, which does not protrude from the outer surface.

14. The battery cell according to claim 13, characterized in that, The outer surface is provided with a fourth groove, and the solder mark is at least partially accommodated in the fourth groove.

15. The battery cell according to any one of claims 1-14, characterized in that, The vent valve also includes a support member, which is made of a breathable material. The support member covers the second vent hole and is located between the second vent hole and the breathable membrane along the thickness direction of the wall. The breathable membrane abuts against the support member.

16. The battery cell according to claim 15, characterized in that, The limiting member has a third surface, the third surface is provided with a fifth groove, the second vent hole is provided on the bottom wall of the fifth groove, and the support member is at least partially accommodated in the fifth groove.

17. The battery cell according to claim 16, characterized in that, The surface of the support member facing the breathable membrane is flush with the third surface.

18. The battery cell according to claim 15, characterized in that, In a projection plane perpendicular to the thickness direction of the wall, the orthographic projection of the seal is arranged around the orthographic projection of the support.

19. The battery cell according to any one of claims 1-14, characterized in that, A boss is provided on the wall, the boss is arranged around the first vent hole, and the sealing element is sleeved on the boss.

20. The battery cell according to any one of claims 1-14, characterized in that, The battery cell includes a pressure relief mechanism disposed on the wall portion. The pressure relief mechanism includes a weak portion, which is configured to be at least partially destroyed when the internal pressure of the battery cell reaches a threshold.

21. The battery cell according to any one of claims 1-14, characterized in that, The battery cell includes an electrode assembly housed in the housing, and the wall portion is located at the bottom of the electrode assembly and supports the electrode assembly.

22. The battery cell according to any one of claims 1-14, characterized in that, The outer casing includes: The housing includes an integrally formed bottom wall and a side wall, the side wall surrounding the bottom wall, and the end of the side wall away from the bottom wall forming an opening; End cap, to close the opening; The bottom wall is the wall portion.

23. The battery cell according to any one of claims 1-14, characterized in that, The battery cell includes an electrode assembly, which is housed within the housing; The electrode assembly includes a positive electrode sheet, the positive electrode sheet includes a positive electrode active material capable of reversibly extracting and inserting metal ions, and the positive electrode active material includes a nickel-containing compound; The nickel-containing compound includes a layered lithium-containing transition metal oxide, wherein the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 50% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide. Optionally, the molar amount of nickel in the layered lithium-containing transition metal oxide accounts for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

24. The battery cell according to any one of claims 1-14, characterized in that, The battery cell includes an electrode assembly, which is housed within the housing; The electrode assembly includes a negative electrode sheet, the negative electrode sheet includes a negative electrode active material, and the negative electrode active material includes elemental sodium metal.

25. The battery cell according to any one of claims 1-14, characterized in that, The base metal of the outer shell is iron or titanium.

26. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-25.

27. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1-25, the battery cell being used to provide electrical energy to the electrical device.

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