Battery cell, battery device, electric apparatus and energy storage apparatus

Abstract

Provided in the embodiments of the present application are a battery cell, a battery device, an electric apparatus and an energy storage apparatus. The energy density of the battery cell can be improved. The battery cell comprises: an electrode assembly, a casing, a pressure relief mechanism and a support structure, wherein an accommodating cavity is formed inside the casing, and the electrode assembly is accommodated in the accommodating cavity; the casing has a first wall, the first wall is provided with a pressure relief hole, the pressure relief hole is in communication with the accommodating cavity, and the pressure relief hole comprises a first hole and a second hole that are distributed in a stepped manner, one end of the first hole being formed on the surface of the side of the first wall facing the electrode assembly, and the second hole being located on the side of the first hole facing away from the accommodating cavity; the pressure relief mechanism is accommodated in the first hole and connected to the casing; the support structure is fixed to the side of the first wall facing the electrode assembly; and the pressure relief mechanism is located on the side of the support structure facing away from the electrode assembly, and the pressure relief mechanism is welded to at least one of the support structure and the first wall.

Description

Battery cells, battery devices, electrical equipment and energy storage devices Cross-reference to related applications

[0001] This application claims priority to Chinese patent application 202411016887.3, filed on July 26, 2024, entitled “Battery cell, battery device, electrical equipment and energy storage device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery cell, battery device, electrical device, and energy storage device. Background Technology

[0003] With increasing environmental pollution, the new energy industry is attracting more and more attention. Battery technology is a crucial factor in the development of the new energy industry. Therefore, improving the electrical performance of battery devices through modifications to the structure of individual battery cells has become a pressing technical problem in this field. Summary of the Invention

[0004] This application provides a battery cell, a battery device, an electrical device, and an energy storage device, which can improve the energy density of the battery cell.

[0005] In a first aspect, a battery cell is provided, comprising: an electrode assembly; a housing having an internal cavity in which the electrode assembly is housed, the housing having a first wall, the first wall having a pressure relief hole communicating with the cavity, the pressure relief hole including a first hole and a second hole distributed in a stepped manner, one end of the first hole being formed on the surface of the first wall facing the electrode assembly, the second hole being located on the side of the first hole facing away from the cavity; a pressure relief mechanism housed in the first hole and connected to the housing; a support structure fixed to the side of the first wall facing the electrode assembly, the pressure relief mechanism being located on the side of the support structure facing away from the electrode assembly, and the pressure relief mechanism being welded to at least one of the support structure and the first wall.

[0006] In this embodiment, by configuring the pressure relief hole as a first hole and a second hole distributed in a stepped manner, one end of the first hole is formed on the surface of the first wall facing the electrode assembly, and the second hole is located on the side of the first hole away from the receiving cavity. The pressure relief mechanism is accommodated in the first hole and connected to the housing. The support structure is fixed to the side of the first wall facing the electrode assembly, and the pressure relief mechanism is located on the side of the support structure away from the electrode assembly. The pressure relief mechanism is welded to at least one of the support structure and the first wall. Compared with the prior art, which requires additional space on the housing to support the pressure relief mechanism, the technical solution of this embodiment can accommodate the pressure relief mechanism in the first hole and fix the pressure relief mechanism to the side of the support structure away from the electrode assembly, thereby reducing the thickness of the first wall and making the thickness of the battery cell housing thinner, thereby improving the energy density and performance of the battery cell. Secondly, the second hole can provide expansion space for the pressure relief mechanism to release the pressure inside the battery cell, thereby improving the performance of the pressure relief mechanism.

[0007] In some implementations, the pressure relief mechanism, the support structure, and the first wall are connected by the same weld mark, and the orthographic projection of the support structure covers the orthographic projection of the weld mark on a plane perpendicular to the thickness direction of the first wall.

[0008] In this embodiment, the pressure relief mechanism, the support structure, and the first wall are connected by the same weld mark. On a plane perpendicular to the thickness direction of the first wall, the orthogonal projection of the support structure covers the orthogonal projection of the weld mark, thereby reducing the impact of high-temperature and high-pressure emissions from inside the battery cell on the welded part. This effectively improves the overall structural strength and stability of the fixed connection between the pressure relief mechanism, the support structure, and the first wall, and thus improves the performance of the battery cell.

[0009] In some implementations, the side of the pressure relief mechanism closest to the inner wall of the first hole abuts against the inner wall of the first hole. Thus, in this embodiment, by having the side of the pressure relief mechanism closest to the inner wall of the first hole abut against the inner wall of the first hole, a fixed connection between the pressure relief mechanism and the first wall is facilitated, as is a welding connection between the inner wall of the pressure relief mechanism and the inner wall of the first hole. This improves the structural strength between the pressure relief mechanism and the first wall, and increases the assembly efficiency of the battery cell. Furthermore, this arrangement is simple and easy to process and manufacture.

[0010] In some implementations, the surface of the support structure facing the first wall, the surface of the pressure relief mechanism facing the electrode assembly, and the surface of the first wall facing the electrode assembly are all in the same plane.

[0011] In this embodiment, by placing the surface of the support structure facing the first wall, the surface of the pressure relief mechanism facing the electrode assembly, and the surface of the first wall facing the electrode assembly all in the same plane, the support structure can be fixedly connected to the pressure relief mechanism and the first wall, which helps to reduce the processing difficulty and thus improve the processing and manufacturing efficiency of the battery cell.

[0012] In some implementations, the battery cell further includes a base plate, which is housed within the receiving cavity and located between the electrode assembly and the first wall. The base plate supports the electrode assembly. Thus, in this embodiment, by providing a base plate within the battery cell, the base plate supports the electrode assembly inside the battery cell, reducing the risk that the high-temperature, high-pressure gas generated by the electrode assembly may not reach the pressure relief mechanism due to insufficient space between the electrode assembly and the first wall. Simultaneously, it reduces the risk of damage to the battery cell casing caused by the high-temperature, high-pressure gas, thereby improving the performance of the battery cell.

[0013] In some implementations, the base plate includes a main body and a protrusion, the side of the protrusion facing away from the first wall being connected to the main body, and the side of the protrusion facing the first wall being attached to the first wall; an exhaust channel communicating with the pressure relief mechanism is formed between the main body and the first wall.

[0014] In this embodiment, the base plate is configured to include a main body and a protrusion. The side of the protrusion away from the first wall is connected to the main body, and the side of the protrusion facing the first wall is attached to the first wall. An exhaust channel communicating with the pressure relief mechanism is formed between the main body and the first wall. In the event of thermal runaway of the battery cell, the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell in a timely manner through the exhaust space and the pressure relief mechanism, thereby improving the performance of the battery cell.

[0015] In some implementations, the orthographic projection of the protrusion does not overlap with the orthographic projection of the support structure on a plane perpendicular to the thickness direction of the first wall, and the orthographic projection of the protrusion does not overlap with the orthographic projection of the pressure relief mechanism.

[0016] In this embodiment of the application, by setting the orthographic projection of the protrusion on a plane perpendicular to the thickness direction of the first wall to not overlap with the orthographic projection of the support structure, and the orthographic projection of the protrusion not overlapping with the orthographic projection of the pressure relief mechanism, the assembly of the base plate does not affect the performance of the pressure relief mechanism and does not interfere with the support structure. At the same time, it facilitates the installation and disassembly of the base plate and helps to improve the assembly efficiency of the battery cell.

[0017] In some implementations, the distance H1 between the main body and the first wall in the thickness direction of the first wall is greater than the dimension H2 of the support structure. Thus, in this embodiment, by making the distance H1 between the main body and the first wall greater than the dimension H2 of the support structure in the thickness direction of the first wall, the impact of the support structure on the base plate is reduced during the actuation of the pressure relief mechanism of the battery cell. This allows the high-temperature, high-pressure gas generated inside the battery cell to be promptly discharged to the outside of the battery cell through the space between the base plate and the support structure when the temperature or pressure inside the battery cell reaches a threshold, thereby improving the performance of the pressure relief mechanism and ultimately improving the performance of the battery cell.

[0018] In some implementations, in the thickness direction of the first wall, the distance H1 between the main body and the first wall and the dimension H2 of the support structure satisfy: 0mm < H1 - H2 ≤ 5mm.

[0019] In this embodiment of the application, in the thickness direction of the first wall, the difference H1-H2 between the distance H1 between the main body and the first wall and the dimension H2 of the support structure is set to be greater than 0 mm and less than or equal to 5 mm, which can effectively balance the performance of the pressure relief mechanism and the space utilization rate inside the battery cell, thereby improving the performance of the battery cell.

[0020] In some implementations, the dimension H2 of the support structure in the thickness direction of the first wall is greater than or equal to 0.3 mm. Thus, in this embodiment, by setting the dimension H2 of the support structure in the thickness direction of the first wall to be greater than or equal to 0.3 mm, the structural strength of the connection between the support structure, the first wall, and the pressure relief mechanism is improved. Simultaneously, the risk of the weld between the first wall and the pressure relief mechanism penetrating the support structure along the thickness direction of the first wall and towards the electrode assembly is reduced, thereby improving the performance of the battery cell.

[0021] In some implementations, the thickness D1 of the first wall satisfies: 0.6mm ≤ D1 ≤ 3mm. Thus, in the embodiment of this application, when the pressure relief holes on the first wall are configured as a first hole and a second hole distributed in a stepped manner, by setting the thickness D1 of the first wall to satisfy: 0.6mm ≤ D1 ≤ 3mm, both the structural strength of the casing and the performance of the battery cell can be taken into account.

[0022] In some implementations, the thickness D1 of the first wall satisfies: 0.8mm ≤ D1 ≤ 1.5mm. Thus, in this embodiment of the application, when the pressure relief holes on the first wall are configured as a first hole and a second hole distributed in a stepped manner, by setting the thickness D1 of the first wall to satisfy: 0.8mm ≤ D1 ≤ 1.5mm, the structural strength of the casing and the performance of the battery cell can be effectively balanced.

[0023] In some implementations, the pressure relief hole also includes a third hole located on the side of the second hole opposite to the first hole. The battery cell also includes a protective member housed in the third hole and connected to the housing. On a plane perpendicular to the thickness direction of the first wall, the orthographic projection of the protective member covers the orthographic projection of the pressure relief mechanism.

[0024] In this embodiment, the pressure relief hole further includes a third hole located on the side of the second hole away from the first hole. The battery cell is also provided with a protective member, which is accommodated in the third hole and connected to the housing. On a plane perpendicular to the thickness direction of the first wall, the orthographic projection of the protective member covers the orthographic projection of the pressure relief mechanism. Compared with the prior art, which places the protective member on the surface of the first wall away from the inside of the battery cell, i.e., the protective member protrudes from the outside of the battery cell housing, the technical solution of this embodiment can protect the protective member, thereby reducing the risk of wear or damage to the protective member during use. It also helps to protect the pressure relief mechanism, ensuring its performance and thus improving the performance of the battery cell.

[0025] In some implementations, the size of the pressure relief hole gradually increases in the direction perpendicular to the thickness of the first wall from the first hole to the third hole. Thus, in this embodiment, by setting the size of the pressure relief hole to gradually increase in the direction perpendicular to the thickness of the first wall from the first hole to the third hole, it facilitates the assembly of the pressure relief mechanism and the protective component. Specifically, the pressure relief mechanism is installed in the first hole, and the protective component is installed in the third hole, which improves the assembly efficiency of the battery cell.

[0026] In some implementations, the thickness D2 of the first wall satisfies: 0.8mm ≤ D2 ≤ 3.2mm. Thus, in the embodiment of this application, when the pressure relief holes on the first wall are configured as a stepped distribution of the first hole, the second hole, and the third hole, by setting the thickness D2 of the first wall to satisfy: 0.8mm ≤ D2 ≤ 3.2mm, both the structural strength of the casing and the performance of the battery cells can be taken into account.

[0027] In some implementations, the thickness D2 of the first wall satisfies: 1mm ≤ D2 ≤ 1.7mm. Thus, in the embodiments of this application, when the pressure relief holes on the first wall are configured as a first hole, a second hole, and a third hole distributed in a stepped manner, by setting the thickness D2 of the first wall to satisfy: 1mm ≤ D2 ≤ 1.7mm, the structural strength of the casing and the performance of the battery cells can be effectively balanced.

[0028] In some implementations, the support structure is arranged around the outer periphery of the pressure relief mechanism. Thus, in this embodiment, by arranging the support structure around the outer periphery of the pressure relief hole, a fixed connection is achieved between the support structure, the first wall, and the pressure relief mechanism, which also helps to improve the processing and manufacturing efficiency of the battery cell.

[0029] In some implementations, the support structure is a ring structure, with the inner ring of the ring structure surrounding the pressure relief hole. Thus, in this embodiment, by setting the support structure as a ring structure with the inner ring surrounding the pressure relief hole, and with a base plate inside the battery cell, the volume of the exhaust space between the base plate and the first wall occupied by the support structure can be reduced without affecting the performance of the pressure relief mechanism. When the internal temperature or pressure of the battery cell reaches a threshold, the high-temperature, high-pressure gas generated inside the battery cell can be discharged to the outside of the battery cell sequentially through the base plate, the ring structure, and the pressure relief mechanism, improving the performance of the pressure relief mechanism. Furthermore, the ring structure is easy to process and manufacture, which helps improve the processing and manufacturing efficiency of the battery cell.

[0030] In some implementations, the width D3 of the support structure satisfies: 0.5mm ≤ D3 ≤ 10mm. Thus, in this embodiment, the support structure is a ring structure, and the width D3 of the support structure is set to be greater than or equal to 0.5mm and less than or equal to 10mm, so as to balance the overall structural strength between the support structure, the first wall and the pressure relief mechanism and the performance of the pressure relief mechanism, thereby improving the performance of the battery cell.

[0031] In some implementations, the support structure, the first wall, and the pressure relief mechanism are made of one of the following materials: steel, aluminum, or titanium alloy. Thus, in this embodiment, by setting the materials of the support structure, the first wall, and the pressure relief mechanism to one of the following materials—steel, aluminum, or titanium alloy—the welding connection between the support structure, the first wall, and the pressure relief mechanism is facilitated, improving the processing and manufacturing efficiency of the battery cell while reducing processing and manufacturing costs.

[0032] In some implementations, the support structure, the first wall, and the pressure relief mechanism are all made of one of the following materials: steel, aluminum, or titanium alloy. Thus, in this embodiment, by using steel, aluminum, or titanium alloy for the support structure, the first wall, and the pressure relief mechanism, the welding connection between them is facilitated, further improving the processing and manufacturing efficiency of the battery cell while reducing processing and manufacturing costs.

[0033] In a second aspect, a battery is provided, comprising a plurality of battery cells, wherein the battery cells are those described in the first aspect or any embodiment thereof.

[0034] Thirdly, an electrical device is provided, including the battery described in the second aspect, which is used to provide electrical energy to the electrical device.

[0035] In some implementations, the electrical equipment can be a vehicle, a ship, or a spacecraft.

[0036] Fourthly, an energy storage device is provided, including the battery described in the second aspect, the battery being used to store electrical energy for the energy storage device. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0038] Figure 1 is a structural schematic diagram of a vehicle provided in an embodiment of this application.

[0039] Figure 2 is an exploded view of a battery device provided in an embodiment of this application.

[0040] Figure 3 is a schematic diagram of the structure of a battery cell provided in an embodiment of this application.

[0041] Figure 4 is an exploded structural diagram of a battery cell provided in an embodiment of this application.

[0042] Figure 5 is an exploded structural diagram of a battery cell provided in another embodiment of this application.

[0043] Figure 6 is a cross-sectional schematic diagram of a battery cell provided in an embodiment of this application.

[0044] Figure 7 is a partially enlarged cross-sectional schematic diagram of a battery cell provided in another embodiment of this application.

[0045] Figure 8 is a partially enlarged cross-sectional schematic diagram of a battery cell provided in another embodiment of this application.

[0046] Figure 9 is a partially enlarged cross-sectional schematic diagram of a battery cell provided in another embodiment of this application.

[0047] Figure 10 is a cross-sectional schematic diagram of the base plate provided in an embodiment of this application.

[0048] Figure 11 is a cross-sectional schematic diagram of the base plate provided in another embodiment of this application.

[0049] Figure 12 is a cross-sectional schematic diagram of a battery cell provided in another embodiment of this application.

[0050] Figure 13 is a cross-sectional schematic diagram of a battery cell provided in another embodiment of this application.

[0051] Explanation of reference numerals in the attached drawings: 1-Vehicle; 10-Battery unit; 20-Battery cell; 30-Controller; 40-Motor; 11-Box; 21-Shell; 22-Electrode assembly; 211-Shell; 212-Cover plate; 213-Pressure relief mechanism; 222a-Positive electrode tab; 222b-Negative electrode tab; 214-Electrode terminal; 214a-Positive electrode terminal; 214b-Negative electrode terminal; 23-Base plate; 24-Insulator; 25-Bonding component; 26-Injection hole; 27-Support structure; 271-Sub-support structure; 28-Protective component; 231-Main body; 232-Protrusion; 233-Vent hole; 50-First wall; 60-Pressure relief hole; 610-First hole; 620-Second hole; 630-Third hole; 70-Gap.

[0052] The accompanying drawings are not drawn to scale. Detailed Implementation

[0053] The implementation of this application will be further described in detail below with reference to the accompanying drawings and embodiments. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0054] In the description of the embodiments of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0055] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0056] The term "and / or" in the embodiments of this application is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in the embodiments of this application generally indicates that the preceding and following related objects have an "or" relationship.

[0057] Unless otherwise defined, all technical and scientific terms used in the embodiments of 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 specification of this application is for the purpose of describing specific embodiments only and is not intended to limit the embodiments of this application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of the embodiments of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of the embodiments of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0058] In this application, the reference to "embodiment" means that a specific 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 throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0059] In this application, a battery refers to a physical module comprising one or more battery cells to provide electrical energy. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing can reduce the impact of liquids or other foreign matter on the charging or discharging of the battery cells.

[0060] It should be understood that the battery cells in the embodiments of this application 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.

[0061] In some implementations, 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 the 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, prevents short circuits while allowing active ions to pass through.

[0062] In some implementations, the positive electrode can 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.

[0063] 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.

[0064] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, 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.).

[0065] 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. In some implementations, other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4, also known 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.

[0066] As an example, the positive electrode active material may include at least one of sodium transition metal oxides, polyanionic compounds, and Prussian blue compounds.

[0067] In some implementations, the sodium transition metal oxide can be a doped sodium transition metal oxide, and the doping modification of the sodium transition metal oxide can include at least one of sodium site doping modification, oxygen site doping modification, transition metal site doping modification, and surface coating modification.

[0068] In some implementations, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, or foamed carbon, 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 materials, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, with the lithium source material being lithium metal and / or lithium-rich materials.

[0069] In some implementations, the negative electrode can be a negative electrode sheet, which can include a negative electrode current collector.

[0070] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors 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.).

[0071] In some implementations, the battery cell in the embodiments of this application may be a sodium-free secondary battery.

[0072] A negative electrode-less sodium secondary battery refers to a battery cell in which a negative electrode active material layer is not actively formed on the negative electrode side during the battery cell manufacturing process. For example, a sodium metal or carbonaceous active material layer is not formed at the negative electrode through coating or deposition processes during the battery cell manufacturing process. During the first charge, sodium ions gain electrons on the anode side to deposit on the current collector surface to form a sodium metal phase. During discharge, the metallic sodium can be converted into sodium ions and return to the positive electrode, achieving charge-discharge cycles. Compared with other sodium secondary batteries, a negative electrode-less sodium secondary battery cell can achieve a higher energy density because it lacks a negative electrode active material layer.

[0073] In some implementations, in order to improve the performance of individual cells, functional coatings such as carbonaceous materials, metal oxides, and alloys can be applied to the negative electrode side of the sodium-free secondary battery to improve the conductivity of the negative electrode current collector and the uniformity of the deposited sodium metal.

[0074] In some implementations, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0075] In some implementations, the electrode assembly also includes an isolator disposed between the positive and negative electrodes.

[0076] In some implementations, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0077] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

[0078] In some implementations, the separator is a solid electrolyte. The solid electrolyte is placed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0079] In some implementations, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0080] In some implementations, the electrode assembly can be a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0081] In some implementations, the electrode assembly is a stacked structure. As an example, multiple positive and negative electrodes can be provided, with multiple positive and multiple negative electrodes stacked alternately.

[0082] 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.

[0083] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0084] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0085] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0086] In some implementations, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0087] In some implementations, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. These tabs include positive and negative tabs.

[0088] In some implementations, the battery cell may include a casing. The casing is used to encapsulate components such as electrode assemblies and electrolytes. The casing can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0089] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0090] To meet diverse power demands, the battery in this embodiment may include multiple individual battery cells, which can be connected in series, parallel, or a combination thereof. In some implementations, multiple individual battery cells can first be connected in series, parallel, or a combination thereof to form a battery module, and then these battery modules can be connected in series, parallel, or a combination thereof to form a battery. In other words, multiple individual battery cells can directly form a battery, or they can first be assembled into a battery module, and then the battery modules can be assembled into a battery. The battery is then further installed in electrical equipment to provide power to the equipment.

[0091] In some implementations, the battery in the embodiments of this application can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0092] In some implementations, the battery in this application embodiment can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed in the housing.

[0093] In some implementations, the housing in this application embodiment can be part of the vehicle's chassis structure. For example, a portion of the housing can be at least a part of the vehicle's floor, or a portion of the housing can be at least a part of the vehicle's crossbeams and longitudinal beams.

[0094] With increasing environmental pollution, the new energy industry is attracting growing attention. Battery technology is a crucial factor in the development of this industry. Currently, sufficient assembly and expansion space needs to be reserved on the walls of battery cells for pressure relief mechanisms. For example, space needs to be reserved on the side of the pressure relief mechanism near the electrode assembly of the battery cell to support or fix the mechanism. This means the bottom wall needs to have a certain thickness, which reduces the internal space of the battery cell, lowers its space utilization, and consequently reduces its volumetric energy density. Therefore, improving the electrical performance of battery devices through improvements to the battery cell structure has become a pressing technical problem in the development of battery technology.

[0095] In view of this, embodiments of this application provide a battery cell, which includes an electrode assembly, a housing, a pressure relief mechanism, and a support structure. The housing forms a receiving cavity inside, and the electrode assembly is received in the receiving cavity. The housing has a first wall, and the first wall is provided with a pressure relief hole that communicates with the receiving cavity. The pressure relief hole includes a first hole and a second hole distributed in a stepped manner. One end of the first hole is formed on the surface of the first wall facing the electrode assembly, and the second hole is located on the side of the first hole away from the receiving cavity. The pressure relief mechanism is received in the first hole and connected to the housing. The support structure is fixed to the side of the first wall facing the electrode assembly, and the pressure relief mechanism is located on the side of the support structure away from the electrode assembly. The pressure relief mechanism is welded to at least one of the support structure and the first wall. Thus, in this embodiment, by setting the pressure relief hole as a first hole and a second hole distributed in a stepped manner, one end of the first hole is formed on the surface of the first wall facing the electrode assembly, and the second hole is located on the side of the first hole away from the receiving cavity. The pressure relief mechanism is accommodated in the first hole and connected to the housing. The support structure is fixed to the side of the first wall facing the electrode assembly, and the pressure relief mechanism is located on the side of the support structure away from the electrode assembly. The pressure relief mechanism is welded to at least one of the support structure and the first wall. Compared with the prior art, which requires a space on the housing to support the pressure relief mechanism, the technical solution of this embodiment can accommodate the pressure relief mechanism in the first hole and fix the pressure relief mechanism to the side of the support structure away from the electrode assembly, thereby reducing the thickness of the first wall and making the thickness of the battery cell housing thinner, thereby improving the energy density and performance of the battery cell. Secondly, the second hole can provide expansion space for the pressure relief mechanism to release the pressure inside the battery cell, thereby improving the performance of the pressure relief mechanism.

[0096] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices. For example, such electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0097] It should be understood that the technical solutions described in the embodiments of this application are not limited to the electrical equipment described above, but can also be applied to all equipment using battery devices. For the sake of simplicity, the following embodiments will be described in detail using a vehicle as an example of electrical equipment.

[0098] For example, as shown in Figure 1, which is a structural schematic diagram of a vehicle 1 provided in an embodiment of this application, the vehicle 1 can be a gasoline vehicle, a natural gas vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. The interior of the vehicle 1 can be equipped with a motor 40, a controller 30, and a battery device 10. The controller 30 is used to control the battery device 10 to supply power to the motor 40. For example, the battery device 10 can be located at the bottom, front, or rear of the vehicle 1. The battery device 10 can be used to power the vehicle 1. For example, the battery device 10 can serve as the operating power source for the vehicle 1's electrical system; it can also be used for the starting, navigation, and operation power needs of the vehicle 1. In some implementations of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power for the vehicle 1.

[0099] To meet different power demands, the battery device 10 in this embodiment may include at least one battery cell group, which comprises multiple battery cells. These multiple battery cells can be electrically connected in series, parallel, or a combination thereof to form the battery device 10. A combination of series and parallel connections refers to a mix of both. The battery device 10 may also be called a battery pack. For example, multiple battery cells can first be connected in series, parallel, or a combination thereof to form a battery module, and then these battery modules can be connected in series, parallel, or a combination thereof to form the battery device 10. That is, multiple battery cells can directly form the battery device 10, or they can first be formed into battery modules, and then the battery modules can be combined to form the battery device 10.

[0100] In some implementations, the battery device 10 may include multiple battery cells. For example, as shown in FIG2, which is a structural schematic diagram of a battery device 10 according to an embodiment of this application, the battery device 10 may include multiple battery cells 20. The battery device 10 may also include a housing 11, which has a hollow internal structure, and the multiple battery cells 20 are housed within the housing 11. For example, the multiple battery cells 20 may be connected in parallel, in series, or in a mixed configuration and then placed within the housing 11.

[0101] As shown in Figure 2, the housing 11 may include two parts, referred to here as the first part 111 and the second part 112, which are fastened together. The shapes of the first part 111 and the second part 112 can be determined according to the combined shape of multiple battery cells 20. Both the first part 111 and the second part 112 may have an opening. For example, both the first part 111 and the second part 112 may be hollow cuboids with only one open face. The openings of the first part 111 and the second part 112 are opposite to each other, and the first part 111 and the second part 112 are fastened together to form a housing 11 with a closed cavity. The housing 11 may include a bottom plate 112a, side plates 112b, and beams. Multiple battery cells 20 are connected in parallel, series, or mixed configurations and placed inside the housing formed by the fastening of the first part 111 and the second part 112.

[0102] In this embodiment, the number of battery cells 20 can be set to any value according to different power requirements. Multiple battery cells 20 can be connected in series, parallel, or mixed connection to achieve a larger capacity or power. Since each battery device 10 may include a large number of battery cells 20, for ease of installation, the battery cells 20 can be grouped, with each group of battery cells 20 forming a battery module. The number of battery cells 20 included in a battery module is not limited and can be set according to requirements. The battery device 10 may include multiple battery modules, which can be connected in series, parallel, or mixed connection.

[0103] Figure 3 shows a structural schematic diagram of a battery cell 20 provided in one embodiment of this application, and Figure 4 shows an exploded structural schematic diagram of a battery cell 20 provided in another embodiment of this application. As shown in Figures 3 and 4, the battery cell 20 of this embodiment may include: a housing 21 and an electrode assembly 22. The housing 21 has a closed receiving space, and the electrode assembly 22 is placed in the receiving space within the housing 21. The housing 21 may include a shell 211 and a cover plate 212. The shell 211 is a hollow structure with at least one opening; the cover plate 212 is used to fasten with the shell 211 to form a housing 21 with a closed receiving space.

[0104] In some embodiments, the cover plate 212 may be a plate-like structure used to cover the opening of the housing 211. In other embodiments, the cover plate 212 has a similar structure to the housing 211, that is, both the housing 211 and the cover plate 212 are hollow structures with one opening, and the two openings are joined together to form an outer shell 21 with a closed accommodating space.

[0105] It should be understood that if the cover plate 212 is a plate-shaped structure, the shell 211 can be a hollow structure with an opening at one or more ends. For example, if the shell 211 is a hollow structure with an opening at one end, the cover plate 212 can be set as one; if the shell 211 is a hollow structure with openings at opposite ends, the cover plate 212 can be set as two, and the two cover plates 212 respectively cover the openings at both ends of the shell 211.

[0106] The outer shell 21 can be of various shapes, such as a cylinder, a cuboid, or other polyhedrons. For example, as shown in Figures 3 and 4, in this embodiment of the application, the outer shell 21 is mainly described as a cuboid structure.

[0107] It should be understood that the cover plate 212 in this embodiment of the application is used to cooperate with the housing 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover plate 212 can be adapted to the shape of the housing 211, as shown in Figures 3 and 4. The housing 211 is a cuboid structure, and the cover plate 212 is a rectangular plate structure adapted to the housing 211.

[0108] In some embodiments, the housing 211 may be a hollow structure with an opening at at least one end, and the shape of the cover plate 212 may be adapted to the shape of the housing 211. The cover plate 212 is used to cover the opening of the housing 211 so that the housing 21 isolates the internal environment of the battery cell 20 from the external environment. If the housing 211 is a hollow structure with an opening at one end, the cover plate 212 may be provided as one.

[0109] The shell 211 in this embodiment may be made of one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The cover plate 212 may also be made of one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 may be the same as or different from that of the shell 211; the materials of the different walls of the shell 211 may also be the same or different.

[0110] The cover plate 212 in this embodiment can be any wall of the outer shell 21. For example, the cover plate 212 can be the wall with the largest area among the multiple walls included in the outer shell 21, or the wall with the smallest area, or it can be other walls. This embodiment is not limited to this. Alternatively, the cover plate 212 can also be other structures. For example, the cover plate 212 can also be a groove structure with an opening to cover the opening of the housing 211. This embodiment is not limited to this.

[0111] It should be understood that the battery cell 20 also includes electrode terminals 214. In this embodiment, the electrode terminals 214 are used for electrical connection with the electrode assembly 22 inside the battery cell 20 to output electrical energy from the battery cell 20. As shown in Figures 3 and 4, the battery cell 20 may include at least two electrode terminals 214, which may include at least one positive electrode terminal 214a and at least one negative electrode terminal 214b. The positive electrode terminal 214a is used for electrical connection with the positive electrode tab 222a of the electrode assembly 22, and the negative electrode terminal 214b is used for electrical connection with the negative electrode tab 222b of the electrode assembly 22. The positive electrode terminal 214a and the positive electrode tab 222a can be directly connected or indirectly connected, and the negative electrode terminal 214b and the negative electrode tab 222b can be directly connected or indirectly connected. For example, the positive electrode terminal 214a can be electrically connected to the positive electrode tab 222a through a connecting member (not shown in the figure), and the negative electrode terminal 214b can be electrically connected to the negative electrode tab 222b through a connecting member.

[0112] In this embodiment, the walls of the housing 211 and the cover plate 212 are both referred to as the walls of the battery cell 20. For the cuboid battery cell 20 shown in Figures 3 and 4, the walls of the housing 211 include a bottom wall and four side walls. The shape of the housing 211 depends on the shape of the combined one or more electrode assemblies 22. For example, the housing 211 can be a hollow cuboid, cube, or cylinder, and one face of the housing 211 has an opening so that one or more electrode assemblies 22 can be placed inside the housing 211. For example, when the housing 211 is a hollow cuboid or cube, one plane of the housing 211 is an open face, that is, this plane does not have a wall, allowing communication between the inside and outside of the housing 211. When the housing 211 can be a hollow cylinder, the end face of the housing 211 is an open face, that is, this end face does not have a wall, allowing communication between the inside and outside of the housing 211. The cover plate 212 covers the opening and is connected to the housing 211 to form a closed cavity for placing the electrode assembly 22. The casing 211 is filled with an electrolyte, such as an electrolyte solution.

[0113] In some implementations, the battery cell 20 further includes a base plate 23 disposed inside the housing 211, with the side of the base plate 23 away from the electrode assembly 22 attached to the side of the bottom wall of the housing 211 facing the electrode assembly 22. Exemplarily, the base plate 23 may be fixedly connected to or not fixedly connected to the side of the bottom wall of the housing 211 facing the electrode assembly 22; for example, the side of the base plate 23 away from the electrode assembly 22 may be bonded to the side of the bottom wall of the housing 211 facing the electrode assembly 22.

[0114] In some implementations, the cover plate 212 of the battery cell 20 is provided with an injection hole 26, through which electrolyte is injected into the battery cell 20 to replenish the electrolyte in the battery cell 20.

[0115] In this battery cell 20, the electrode assembly 22 is the component in which the electrochemical reaction occurs. Depending on actual usage requirements, the electrode assembly 22 within the casing 211 can be one or more. For example, as shown in Figure 4, the battery cell 20 contains two electrode assemblies 22. The electrode assembly 22 can be a cylinder, a cuboid, etc. If the electrode assembly 22 is cylindrical, the casing 211 can also be cylindrical; if the electrode assembly 22 is cuboid, the casing 211 can also be cuboid. In this embodiment, the material of the casing 211 may include the following materials: copper, iron, aluminum, steel, aluminum alloy, etc.

[0116] In some implementations, the battery cell 20 may also include an insulating member 24 disposed within the receiving space of the housing 211. The insulating member 24 may be a hollow structure with openings at one or more ends. The receiving space within this hollow structure is used to accommodate the electrode assembly 22, thereby improving the insulation performance of the battery cell 20. It should also be understood that in some implementations, the battery cell 20 further includes an adhesive member 25, which may be disposed between the insulating member 24 and the base plate 23 for fixedly connecting the insulating member 24 and the base plate 23. For example, the adhesive member 25 may be an L-shaped structure as shown in Figure 4.

[0117] In some implementations, the battery cell 20 may also include other structures, which will not be described in detail here. For example, the battery cell 20 may also include a busbar (not shown in the figure), which is used to realize the electrical connection between multiple battery cells 20, such as parallel, series, or mixed connection. Specifically, the busbar can realize the electrical connection between battery cells 20 by connecting the electrode terminals of the battery cells 20. Further, the busbar can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of multiple battery cells 20 can be further led out through the housing 11 through a conductive mechanism. Optionally, the conductive mechanism may also be part of the busbar.

[0118] Figure 5 shows an exploded structural diagram of a battery cell 20 according to another embodiment of this application. Figure 6 shows a cross-sectional schematic diagram of a battery cell 20 according to an embodiment of this application. Figure 7 shows a partially enlarged cross-sectional schematic diagram of a battery cell 20 according to an embodiment of this application. Exemplarily, the cross-sectional schematic diagram shown in Figure 7 may be an enlarged cross-sectional schematic diagram of a local area of ​​the battery cell 20 in Figure 6. Figure 8 shows a partially enlarged cross-sectional schematic diagram of a battery cell 20 according to another embodiment of this application. Figure 9 shows a partially enlarged cross-sectional schematic diagram of a battery cell 20 according to another embodiment of this application.

[0119] It should be understood that, for ease of description in the embodiments of this application, as shown in Figures 3 to 9, direction X can be the length direction of the battery cell 20, which is perpendicular to direction Z and direction Y, or direction X can also be the length direction of the base plate 23, or direction X can also be the length direction of the housing 211; direction Y can be the width direction of the battery cell 20, which is perpendicular to direction Z and direction X, or direction Y can also be the width direction of the base plate 23, or direction Y can also be the width direction of the housing 211; direction Z can be the height direction of the battery cell 20, which is perpendicular to direction X and direction Y, or direction Z can also be the thickness direction of the base plate 23, or direction Z can also be the height direction of the housing 211.

[0120] In some implementations, as shown in Figures 5 to 9, the battery cell 20 includes: an electrode assembly 22, a housing 211, a pressure relief mechanism 213, and a support structure 27. The housing 211 has an internal cavity into which the electrode assembly 22 is housed. The housing 211 has a first wall 50, and the first wall 50 is provided with a pressure relief hole 60 communicating with the housing cavity. The pressure relief hole 60 includes a first hole 610 and a second hole 620 distributed in a stepped manner. One end of the first hole 610 is shaped as... The first wall 50 is formed on the surface facing the electrode assembly 22. The second hole 620 is located on the side of the first hole 610 away from the receiving cavity. The pressure relief mechanism 213 is received in the first hole 610 and connected to the housing 211. The support structure 27 is fixed to the side of the first wall 50 facing the electrode assembly 22. The pressure relief mechanism 213 is located on the side of the support structure 27 away from the electrode assembly 22. The pressure relief mechanism 213 is welded to at least one of the support structure 27 and the first wall 50.

[0121] It should be understood that the battery cell 20 in this embodiment can be a polyhedral structure of any shape, that is, the battery cell 20 can include multiple walls, and the first wall 50 can be any one of the walls of the battery cell 20, that is, the pressure relief mechanism 213 can be located on any one of the walls of the battery cell 20. It should also be understood that the direction Y shown in Figures 5 to 9 can be the thickness direction of the first wall 50, and the direction X is perpendicular to the thickness direction of the first wall 50.

[0122] For example, the first wall 50 may include, but is not limited to, the following: the first wall 50 may be the wall with the smallest area of ​​the battery cell 20; the first wall 50 may also be the wall with the largest area of ​​the battery cell 20; the first wall 50 may be the wall of the battery cell 20 on which the electrode terminals 214 are provided; the first wall 50 may be the wall adjacent to the wall of the battery cell 20 on which the electrode terminals 214 are provided; the first wall may be the wall opposite to the wall of the battery cell 20 on which the electrode terminals 214 are provided.

[0123] It should also be understood that the first wall 50 is provided with a pressure relief hole 60, which communicates with the receiving cavity of the housing 211. In other words, a through-hole structure can be provided on the first wall 50 to serve as the pressure relief hole 60. The shape of the pressure relief hole 60 on the plane perpendicular to the thickness direction of the first wall 50 can be set according to actual needs. For example, the shape of the pressure relief hole 60 on the plane perpendicular to the thickness direction of the first wall 50 can be circular, elliptical, polygonal, rectangular, etc. As an example, this application embodiment does not limit this.

[0124] It should also be understood that the shapes of the first hole 610 and the second hole 620 included in the pressure relief hole 60 can be set according to actual needs. For example, on a plane perpendicular to the thickness direction of the first wall 50, the shapes of the first hole 610 and the second hole 620 can be circular, elliptical, polygonal, rectangular, etc. As an example, this application embodiment does not limit this.

[0125] It should also be understood that the pressure relief mechanism 213 in this embodiment refers to an element or component that is actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold to release the internal pressure or temperature. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 20.

[0126] The term "actuation" as used in this application refers to the pressure relief mechanism 213 being activated or undergoing a certain state, thereby releasing the internal pressure and temperature of the battery cell 20. The actions of the pressure relief mechanism 213 may include, but are not limited to, at least a portion of the pressure relief mechanism 213 rupturing, breaking, tearing, or opening. During the actuation process of the pressure relief mechanism 213, the high-temperature and high-pressure substances inside the battery cell 20 are discharged outwards from the actuated portion as waste. This method enables the battery cell 20 to release pressure and temperature under controllable pressure or temperature conditions, thereby preventing potentially more serious accidents.

[0127] The emissions from the battery cell 20 mentioned in this application embodiment include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0128] For example, the pressure relief mechanism 213 may be disposed on the bottom wall of the battery cell 20, or, for example, on the bottom wall of the housing 211. The pressure relief mechanism 213 can be various possible types. For example, the pressure relief mechanism 213 may be a temperature-sensitive pressure relief mechanism configured to melt when the internal temperature of the battery cell 20 with the pressure relief mechanism 213 reaches a threshold; and / or, the pressure relief mechanism 213 may be a pressure-sensitive pressure relief mechanism configured to rupture when the internal gas pressure of the battery cell 20 with the pressure relief mechanism 213 reaches a threshold.

[0129] It should also be understood that in this embodiment, the support structure 27 is fixed to the side of the first wall 50 facing the electrode assembly 22, and the pressure relief mechanism 213 is located on the side of the support structure 27 away from the electrode assembly 22. The pressure relief mechanism 213 is welded to at least one of the support structure 27 and the first wall 50, meaning that the pressure relief mechanism 213 can be welded to both the support structure 27 and the first wall 50 simultaneously. Alternatively, in another implementation, the pressure relief mechanism 213 is welded to the support structure 27 but not to the first wall 50, while the support structure 27 is welded to the first wall 50. That is, the support structure 27 achieves a fixed connection between the pressure relief mechanism 213 and the first wall 50, thus achieving a relatively fixed connection between the pressure relief mechanism 213, the support structure 27, and the first wall 50. Alternatively, in another implementation, a portion of the pressure relief mechanism 213 is only welded to the first wall 50 and not to the support structure 27.

[0130] For example, as shown in FIG7, the support structure 27, the first wall 50, and the pressure relief mechanism 213 can be integrally welded together, that is, all three are directly welded together; or, in some implementations, any two of the support structure 27, the first wall 50, and the pressure relief mechanism 213 can be welded to the third party respectively to achieve a relatively fixed connection between the three. The embodiments of this application are not limited to this. As shown in FIG8, the support structure 27 can be welded to the first wall 50 and the pressure relief mechanism 213 respectively. At least a portion of the area between the first wall 50 and the pressure relief mechanism 213 is not fixedly connected. A gap 70 is formed between the first wall 50 and the pressure relief mechanism 213. The surface of the support structure 27 near the first wall 50 is welded to the surface of the first wall 50 facing the electrode assembly 22 and the surface of the pressure relief mechanism 213 facing the electrode assembly 22 respectively, thereby achieving a relatively fixed connection between the three.

[0131] In this embodiment, the pressure relief hole 60 is configured as a first hole 610 and a second hole 620 arranged in a stepped pattern. One end of the first hole 610 is formed on the surface of the first wall 50 facing the electrode assembly 22, and the second hole 620 is located on the side of the first hole 610 away from the receiving cavity. The pressure relief mechanism 213 is accommodated in the first hole 610 and connected to the housing 211. The support structure 27 is fixed to the side of the first wall 50 facing the electrode assembly 22, and the pressure relief mechanism 213 is located on the side of the support structure 27 away from the electrode assembly 22. The pressure relief mechanism 213 is welded to at least one of the support structure 27 and the first wall 50. Compared with existing... The technical solution requires additional space on the housing 211 to support the pressure relief mechanism 213. The technical solution of this application embodiment can accommodate the pressure relief mechanism 213 in the first hole 610, and the pressure relief mechanism 213 is fixed to the side of the support structure 27 away from the electrode assembly 22, which can reduce the thickness of the first wall 50, thereby reducing the thickness of the housing 211 of the battery cell 20, thereby improving the energy density and performance of the battery cell 20. Secondly, the second hole 620 can provide expansion space for the pressure relief mechanism 213, so that the pressure relief mechanism 213 can release the pressure inside the battery cell 20, thereby improving the performance of the pressure relief mechanism 213.

[0132] In some implementations, the pressure relief mechanism 213, the support structure 27, and the first wall 50 are connected by the same solder joint, and the orthographic projection of the support structure 27 covers the orthographic projection of the solder joint on a plane perpendicular to the thickness direction of the first wall 50.

[0133] It should be understood that the support structure 27, the pressure relief mechanism 213 and the first wall 50 can be fixedly connected by welding. The welded part formed after the fixed connection is located between the support structure 27, the pressure relief mechanism 213 and the first wall 50, so as to achieve a relatively fixed connection between the support structure 27, the pressure relief mechanism 213 and the first wall 50.

[0134] In this embodiment, the pressure relief mechanism 213, the support structure 27, and the first wall 50 are connected by the same weld mark. On a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the support structure 27 covers the orthographic projection of the weld mark, thereby reducing the impact of high-temperature and high-pressure emissions from inside the battery cell 20 on the welded part. This effectively improves the overall structural strength and stability of the fixed connection between the pressure relief mechanism 213, the support structure 27, and the first wall 50, and further improves the performance of the battery cell 20.

[0135] In some implementations, as shown in Figures 7 and 9, the side of the pressure relief mechanism 213 near the inner wall of the first hole 610 abuts against the inner wall of the first hole 610. Thus, in this embodiment, by having the side of the pressure relief mechanism 213 near the inner wall of the first hole 610 abut against the inner wall of the first hole 610, the fixed connection between the pressure relief mechanism 213 and the first wall 50 is facilitated, as is the welding connection between the inner wall of the pressure relief mechanism 213 near the first hole 610 and the inner wall of the first hole 610. This improves the structural strength between the pressure relief mechanism 213 and the first wall 50, and increases the assembly efficiency of the battery cell 20. Furthermore, this configuration is simple and easy to process and manufacture.

[0136] In some implementations, as shown in Figures 7 to 9, the surface of the support structure 27 facing the first wall 50, the surface of the pressure relief mechanism 213 facing the electrode assembly 22, and the surface of the first wall 50 facing the electrode assembly 22 are all in the same plane.

[0137] In this embodiment, by placing the surface of the support structure 27 facing the first wall 50, the surface of the pressure relief mechanism 213 facing the electrode assembly 22, and the surface of the first wall 50 facing the electrode assembly 22 in the same plane, the support structure 27 can be fixedly connected to the pressure relief mechanism 213 and the first wall 50, which helps to reduce the processing difficulty and thus improve the processing and manufacturing efficiency of the battery cell 20.

[0138] In some implementations, as shown in Figures 7 to 9, the battery cell 20 further includes a base plate 23, which is housed in the receiving cavity and located between the electrode assembly 22 and the first wall 50. The base plate 23 is used to support the electrode assembly 22.

[0139] It should also be understood that the base plate 23 in this embodiment can be attached to the side of the first wall 50 facing the interior of the battery cell 20, that is, the side of the base plate 23 facing the first wall 50 can be fixedly connected to or not fixedly connected to the side of the first wall 50 facing the interior of the battery cell 20. When the side of the base plate 23 facing the first wall 50 is fixedly connected to the side of the first wall 50 facing the interior of the battery cell 20, the side of the base plate 23 facing the first wall 50 can be welded or bonded to the side of the first wall 50 facing the interior of the battery cell 20.

[0140] It should also be understood that an exhaust space can be formed between the base plate 23 and the first wall 50. This exhaust space is used to discharge the high-temperature, high-pressure airflow generated by the battery cell 20 to the outside of the battery cell 20 in the event of thermal runaway. The shape and size of the exhaust space can be set according to actual needs. For example, the exhaust space can be the space enclosed between the side of the base plate 23 facing the first wall 50, the side of the first wall 50 facing the interior of the battery cell 20, and the inner wall of the housing 211.

[0141] In this embodiment of the application, by providing a bottom support plate 23 in the battery cell 20, the bottom support plate 23 is used to support the electrode assembly 22 inside the battery cell 20, reducing the risk that the high temperature and high pressure gas generated by the electrode assembly 22 is difficult to reach the pressure relief mechanism 213 due to the small space between the electrode assembly 22 and the first wall 50, and at the same time reducing the risk that the high temperature and high pressure gas will damage the casing 211 of the battery cell 20, thereby improving the performance of the battery cell 20.

[0142] Figure 10 shows a cross-sectional schematic diagram of a base plate 23 provided in one embodiment of this application. Figure 11 shows a cross-sectional schematic diagram of a base plate 23 provided in another embodiment of this application. Exemplarily, the cross-sectional schematic diagram of the base plate 23 shown in Figure 10 may be a cross-sectional schematic diagram of the base plate 23 on the side away from the first wall 50, and the cross-sectional schematic diagram of the base plate 23 shown in Figure 11 may be a cross-sectional schematic diagram of the base plate 23 on the side facing the first wall 50.

[0143] In some implementations, as shown in Figures 7 to 11, the base plate 23 includes a main body 231 and a protrusion 232. The side of the protrusion 232 facing away from the first wall 50 is connected to the main body 231, and the side of the protrusion 232 facing the first wall 50 is attached to the first wall 50. An exhaust channel communicating with the pressure relief mechanism 213 is formed between the main body 231 and the first wall 50.

[0144] It should be understood that the side of the protrusion 232 facing away from the first wall 50 and the side of the main body 231 facing the first wall 50 can be welded or bonded together. As an example, this embodiment of the application does not limit this. The attachment of the side of the protrusion 232 facing the first wall 50 to the side of the first wall 50 facing the electrode assembly 22 can mean that the side of the protrusion 232 facing the first wall 50 and the side of the first wall 50 facing the electrode assembly 22 are fixedly connected or not fixedly connected.

[0145] It should also be understood that the number of protrusions 232 on the base plate 23 can be set according to actual needs. For example, the number of protrusions 232 can be set to four as shown in FIG11, and the four protrusions 232 are symmetrically arranged along the length direction and the width direction of the base plate 23. The four protrusions 232 extend along the length direction of the base plate 23, and on the plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the protrusion 232 does not overlap with the orthographic projection of the support structure 27, and the orthographic projection of the protrusion 232 does not overlap with the orthographic projection of the pressure relief mechanism 213.

[0146] It should also be understood that, in this embodiment of the application, by setting the protrusion 232 as an exhaust channel formed between the main body 231 and the first wall 50 and communicating with the pressure relief mechanism 213, the support structure 27 can reuse the space where the exhaust channel is located in the height direction of the battery cell 20, thereby reducing the thickness of the first wall 50. Secondly, the setting of the protrusion 232 can increase the cross-sectional area of ​​the exhaust channel between the bottom plate 23 and the first wall 50 in the space other than the support structure 27, so that when the temperature or pressure inside the battery cell 20 reaches a threshold, the high temperature and high pressure gas generated by the battery cell 20 can be discharged to the outside of the battery cell in a timely manner through the exhaust channel and the pressure relief mechanism 213, reducing the risk of blockage of the exhaust channel due to its small space or cross-sectional area, and improving the performance of the pressure relief mechanism 213.

[0147] It should also be understood that, as shown in Figure 11, the surface of the base plate 23 is also provided with vent holes 233. The vent holes 233 penetrate the base plate 23 along its thickness direction. For example, the vent holes 233 can penetrate the main body 231 along its thickness direction, or the vent holes 233 can sequentially penetrate the main body 231 and the protrusion 232 along its thickness direction, so that the high-temperature and high-pressure gas generated inside the battery cell 20 can sequentially enter the exhaust channel through the vent holes 233 and be discharged to the outside of the battery cell 20 through the pressure relief mechanism 213. The number of vent holes 233 on the base plate 23 can be set according to actual needs, and this embodiment does not limit this.

[0148] In this embodiment, the base plate 23 is configured to include a main body 231 and a protrusion 232. The side of the protrusion 232 facing away from the first wall 50 is connected to the main body 231, and the side of the protrusion 232 facing the first wall 50 is attached to the first wall 50. An exhaust channel communicating with the pressure relief mechanism 213 is formed between the main body 231 and the first wall 50. In the event of thermal runaway of the battery cell 20, the high-temperature and high-pressure gas generated by the electrode assembly 22 can be discharged to the outside of the battery cell 20 in a timely manner through the exhaust space and the pressure relief mechanism 213, thereby improving the performance of the battery cell 20.

[0149] In some implementations, the orthographic projection of the protrusion 232 does not overlap with the orthographic projection of the support structure 27 on a plane perpendicular to the thickness direction of the first wall 50, and the orthographic projection of the protrusion 232 does not overlap with the orthographic projection of the pressure relief mechanism 213.

[0150] It should also be understood that the non-overlapping of the orthographic projection of the protrusion 232 and the orthographic projection of the pressure relief mechanism 213 means that, on a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the protrusion 232 and the orthographic projection of the pressure relief mechanism 213 do not overlap. In the event of thermal runaway of the battery cell 20, the high-temperature and high-pressure gas generated by the electrode assembly 22 can be discharged to the outside of the battery cell 20 in a timely manner through the exhaust space and the pressure relief mechanism 213 without affecting the performance of the pressure relief mechanism 213.

[0151] In this embodiment, by setting the orthographic projection of the protrusion 232 on a plane perpendicular to the thickness direction of the first wall 50 to not overlap with the orthographic projection of the support structure 27, and by setting the orthographic projection of the protrusion 232 to not overlap with the orthographic projection of the pressure relief mechanism 213, the assembly of the bottom plate 23 does not affect the performance of the pressure relief mechanism 213, and does not interfere with the support structure 27. At the same time, it facilitates the installation and disassembly of the bottom plate 23, which is beneficial to improving the assembly efficiency of the battery cell 20.

[0152] In some implementations, as shown in Figures 7 to 9, the distance H1 between the main body 231 and the first wall 50 in the thickness direction of the first wall 50 is greater than the dimension H2 of the support structure 27.

[0153] It should be understood that in the thickness direction of the first wall 50, the distance H1 between the main body 231 and the first wall 50 is greater than the size H2 of the support structure 27. This can mean that in the thickness direction of the first wall 50, the maximum distance H1 between the main body 231 and the first wall 50 is greater than the maximum size H2 of the support structure 27; or, in the thickness direction of the first wall 50, the minimum distance H1 between the main body 231 and the first wall 50 is greater than the minimum size H2 of the support structure 27; or, in the thickness direction of the first wall 50, the average distance H1 between the main body 231 and the first wall 50 is greater than the average size H2 of the support structure 27.

[0154] It should also be understood that when the distance H1 between the main body 231 and the first wall 50 in the thickness direction of the first wall 50 is greater than the size H2 of the support structure 27, the support structure 27 can be accommodated in the exhaust space between the bottom plate 23 and the first wall 50. This means that the support structure 27 can occupy part of the space in the exhaust space, that is, the support structure 27 can reuse the exhaust space to save the space that needs to be reserved for the support structure 27. This can improve the space utilization rate inside the battery cell 20. In contrast, it can accommodate a larger volume electrode assembly 22 and improve the volumetric energy density of the electric cell 20.

[0155] In this embodiment, by making the distance H1 between the main body 231 and the first wall 50 greater than the size H2 of the support structure 27 in the thickness direction of the first wall 50, the influence of the support structure 27 on the base plate 23 is reduced during the actuation of the pressure relief mechanism 213 of the battery cell 20. This allows the high-temperature and high-pressure gas generated inside the battery cell 20 to be discharged to the outside of the battery cell 20 in a timely manner through the space between the base plate 23 and the support structure 27 when the temperature or pressure inside the battery cell 20 reaches a threshold, thereby improving the performance of the pressure relief mechanism 213 and thus improving the performance of the battery cell 20.

[0156] In some implementations, in the thickness direction of the first wall 50, the distance H1 between the main body 231 and the first wall 50 and the dimension H2 of the support structure 27 satisfy: 0mm < H1 - H2 ≤ 5mm.

[0157] For example, in the thickness direction of the first wall 50, the difference between the distance H1 between the main body 231 and the first wall 50 and the dimension H2 of the support structure 27, i.e., the value of H1-H2, can be set to: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc., or its value is within the range obtained by any combination of the above two values.

[0158] In this embodiment of the application, in the thickness direction of the first wall 50, the difference H1-H2 between the distance H1 between the main body 231 and the first wall 50 and the size H2 of the support structure 27 is set to be greater than 0 mm and less than or equal to 5 mm, which can effectively balance the performance of the pressure relief mechanism 213 and the space utilization rate inside the battery cell 20, thereby improving the performance of the battery cell 20.

[0159] In some other implementations, in the thickness direction of the first wall 50, the distance H1 between the main body 231 and the first wall 50 and the dimension H2 of the support structure 27 satisfy: 0.1mm < H1 - H2 ≤ 3mm.

[0160] In some implementations, the dimension H2 of the support structure 27 in the thickness direction of the first wall 50 is greater than or equal to 0.3 mm. For example, the dimension H2 of the support structure 27 in the thickness direction of the first wall 50 can be set to: 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 2 mm, 3 mm, etc., or its value is within the range obtained by any combination of the above two values.

[0161] In this embodiment, by setting the dimension H2 of the support structure 27 in the thickness direction of the first wall 50 to be greater than or equal to 0.3 mm, the structural strength of the connection between the support structure 27, the first wall 50 and the pressure relief mechanism 213 is improved. At the same time, the risk of the weld between the first wall 50 and the pressure relief mechanism 213 penetrating the support structure 27 along the thickness direction of the first wall 50 and towards the electrode assembly 22 is reduced, thereby improving the performance of the battery cell 20.

[0162] In some implementations, as shown in Figures 7 and 8, the thickness D1 of the first wall 50 satisfies: 0.6mm ≤ D1 ≤ 3mm.

[0163] For example, the thickness D1 of the first wall 50 can be set to: 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc., or its value is within the range obtained by any combination of the above two values.

[0164] In this embodiment of the application, when the pressure relief holes 60 on the first wall 50 are configured as a first hole 610 and a second hole 620 distributed in a stepped manner, the thickness D1 of the first wall 50 is set to satisfy: 0.6mm≤D1≤3mm, so as to take into account both the structural strength of the housing 211 and the performance of the battery cell 20.

[0165] In other implementations, as shown in Figures 7 and 8, the thickness D1 of the first wall 50 satisfies: 0.8mm ≤ D1 ≤ 1.5mm. Thus, in this embodiment, when the pressure relief holes 60 on the first wall 50 are configured as a stepped distribution of the first hole 610 and the second hole 620, by setting the thickness D1 of the first wall 50 to satisfy: 0.8mm ≤ D1 ≤ 1.5mm, both the structural strength of the casing 211 and the performance of the battery cell 20 are effectively balanced.

[0166] In some implementations, as shown in FIG9, the pressure relief hole 60 further includes a third hole 630, which is located on the side of the second hole 620 opposite to the first hole 610. The battery cell 20 also includes a protective member 28, which is accommodated in the third hole 630 and connected to the housing 211. On a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the protective member 28 covers the orthographic projection of the pressure relief mechanism 213.

[0167] It should be understood that the shape of the third hole 630 can be set according to actual needs. For example, on a plane perpendicular to the thickness direction of the first wall 50, the shape of the third hole 630 can be circular, elliptical, polygonal, rectangular, etc. Alternatively, the shape of the third hole 630 can be set according to the shape of the first hole 610 or the second hole 620. As an example, this application embodiment does not limit this.

[0168] It should also be understood that the orthogonal projection of the protective member 28 in this embodiment onto a plane perpendicular to the thickness direction of the first wall 50 covers the orthogonal projection of the pressure relief mechanism 213 onto a plane perpendicular to the thickness direction of the first wall 50, thereby protecting the pressure relief mechanism 213, reducing the risk of wear or damage to the pressure relief mechanism 213 during use, and improving the stability of the pressure relief mechanism 213 in use. The material of the protective member 28 includes, but is not limited to, plastic, rubber, or silicone. The shape of the protective member 28 can be set according to actual needs; for example, the shape of the protective member 28 can be set according to the shape of the pressure relief mechanism 213.

[0169] In this embodiment, the pressure relief hole 60 further includes a third hole 630, which is located on the side of the second hole 620 away from the first hole 610. The battery cell 20 is also provided with a protective member 28, which is accommodated in the third hole 630 and connected to the housing 211. On a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the protective member 28 covers the orthographic projection of the pressure relief mechanism 213. Compared with the prior art, which places the protective member 28 on the surface of the first wall 50 away from the inside of the battery cell 20, i.e., the protective member 28 protrudes from the outside of the housing 211 of the battery cell 20, the technical solution of this embodiment can protect the protective member 28, thereby reducing the risk of wear or damage to the protective member 28 during use. At the same time, it is beneficial to protect the pressure relief mechanism 213, thereby improving the performance of the pressure relief mechanism 213 and thus improving the performance of the battery cell 20.

[0170] In some implementations, the pressure relief hole 60 gradually increases in size in the direction perpendicular to the thickness of the first wall 50, from the first hole 610 to the third hole 630. For example, the pressure relief hole 60 may be a stepped through-hole as shown in FIG9.

[0171] It should be understood that, in this embodiment, the dimension of the first hole 610 in the thickness direction perpendicular to the first wall 50 can be the maximum, minimum, or average dimension of the inner wall of the first hole 610 facing the center in the thickness direction perpendicular to the first wall 50. The dimension of the second hole 620 in the thickness direction perpendicular to the first wall 50 can be the maximum, minimum, or average dimension of the inner wall of the second hole 620 facing the center in the thickness direction perpendicular to the first wall 50. The dimension of the third hole 630 in the thickness direction perpendicular to the first wall 50 can be the maximum, minimum, or average dimension of the inner wall of the third hole 630 facing the center in the thickness direction perpendicular to the first wall 50.

[0172] In this embodiment, from the first hole 610 to the third hole 630, the size of the pressure relief hole 60 in the direction perpendicular to the thickness of the first wall 50 is gradually increased to facilitate the assembly of the pressure relief mechanism 213 and the protective member 28. That is, the pressure relief mechanism 213 is installed in the first hole 610 and the protective member 28 is installed in the third hole 630, which helps to improve the assembly efficiency of the battery cell 20.

[0173] In some implementations, as shown in Figure 9, the thickness D2 of the first wall satisfies: 0.8mm ≤ D2 ≤ 3.2mm.

[0174] For example, the thickness D2 of the first wall 50 can be set to: 0.8mm, 0.9mm, 1mm, 1.5mm, 1.7mm, 2mm, 2.5mm, 3mm, 3.2mm, etc., or its value is within the range obtained by any combination of the above two values.

[0175] In this embodiment of the application, when the pressure relief holes 60 on the first wall 50 are configured as a first hole 610, a second hole 620 and a third hole 630 distributed in a stepped manner, the thickness D2 of the first wall 50 is set to satisfy: 0.8mm≤D2≤3.2mm, so as to take into account both the structural strength of the housing 211 and the performance of the battery cell 20.

[0176] In some other implementations, as shown in Figure 9, the thickness D2 of the first wall satisfies: 1mm ≤ D2 ≤ 1.7mm. Thus, in this embodiment, when the pressure relief holes 60 on the first wall 50 are configured as a stepped distribution of first hole 610, second hole 620, and third hole 630, by setting the thickness D2 of the first wall 50 to satisfy: 1mm ≤ D2 ≤ 1.7mm, both the structural strength of the casing 211 and the performance of the battery cell 20 can be effectively balanced.

[0177] Figure 12 shows a cross-sectional schematic diagram of a battery cell 20 provided in another embodiment of this application, and Figure 13 shows a cross-sectional schematic diagram of a battery cell 20 provided in another embodiment of this application. Exemplarily, Figures 12 and 13 can be cross-sectional schematic diagrams of the first wall 50 of the battery cell 20 facing the interior of the battery cell 20 on a plane perpendicular to the thickness direction of the first wall 50.

[0178] In some implementations, as shown in Figures 12 and 13, the support structure 27 is arranged around the outer periphery of the pressure relief mechanism 213.

[0179] It should be understood that the support structure 27 can be continuously arranged around the outer periphery of the pressure relief hole 60, that is, the support structure 27 can be a closed integral structure. Alternatively, as shown in Figure 13, the support structure 27 can include multiple sub-support structures 271, which can be spaced apart around the outer periphery of the pressure relief hole 60. It should also be understood that when the multiple sub-support structures 271 are spaced apart around the outer periphery of the pressure relief hole 60, the distance between any two adjacent sub-support structures 271 can be set according to actual needs. For example, on a plane perpendicular to the thickness direction of the support structure 27, the distance between the geometric centers of any two adjacent sub-support structures 271 can be set to be equal.

[0180] In this embodiment, by setting the support structure 27 around the outer periphery of the pressure relief hole 60, it is convenient to achieve a fixed connection between the support structure 27, the first wall and the pressure relief mechanism 213, and it is beneficial to improve the processing and manufacturing efficiency of the battery cell 20.

[0181] In some implementations, the support structure 27 is an annular structure, with the inner ring of the annular structure surrounding the pressure relief hole 60.

[0182] It should be understood that in the embodiments of this application, the support structure 27 may be a closed ring structure such as a circular ring, a polygonal ring, a waist-shaped ring, or an irregularly shaped ring. It should also be understood that the support structure 27 may also be a non-closed ring structure, for example, the support structure 27 may be a circular ring with a notch. As an example, the embodiments of this application do not limit this.

[0183] It should also be understood that the annular structure of the support structure 27 can be a contoured ring structure. Specifically, the annular structure of the support structure 27 can be configured according to the shape of the pressure relief hole 60 or the pressure relief mechanism 213. For example, if the shape of the pressure relief hole 60 or the pressure relief mechanism 213 in the plane perpendicular to the thickness direction of the first wall 50 is circular, the support structure 27 can be configured as an annular structure. Alternatively, if the shape of the pressure relief hole 60 or the pressure relief mechanism 213 in the plane perpendicular to the thickness direction of the first wall 50 is oval, the support structure 27 can be configured as an oval ring structure.

[0184] In this embodiment, by setting the support structure 27 as a ring structure, with the inner ring of the ring structure surrounding the pressure relief hole 60, and with the bottom support plate 23 provided inside the battery cell 20, the volume of the exhaust space between the bottom support plate 23 and the first wall 50 occupied by the support structure 27 can be reduced without affecting the performance of the pressure relief mechanism 213. When the internal temperature or pressure of the battery cell 20 reaches a threshold, the high-temperature and high-pressure gas generated inside the battery cell 20 can be discharged to the outside of the battery cell 20 in sequence through the bottom support plate 23, the ring structure, and the pressure relief mechanism 213, thereby improving the performance of the pressure relief mechanism 213. At the same time, the ring structure is easy to process and manufacture, which is beneficial to improving the processing and manufacturing efficiency of the battery cell 20.

[0185] In some implementations, as shown in Figures 7 to 9, Figure 12 and Figure 13, the width D3 of the support structure 27 satisfies: 0.5mm ≤ D3 ≤ 10mm.

[0186] For example, when the support structure 27 is a ring structure, the width D3 of the support structure 27 can be set to: 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc., or its value is within the range obtained by any combination of the above two values.

[0187] In this embodiment, the support structure 27 is a ring structure, and the width D3 of the support structure 27 is set to be greater than or equal to 0.5 mm and less than or equal to 10 mm, so as to take into account the overall structural strength between the support structure 27, the first wall 50 and the pressure relief mechanism 213 and the performance of the pressure relief mechanism 213, thereby improving the performance of the battery cell 20.

[0188] In some other implementations, when the support structure 27 is a ring structure, the width D3 of the support structure 27 satisfies: 1mm≤D3≤5mm.

[0189] In some implementations, the support structure 27, the first wall 50, and the pressure relief mechanism 213 are made of one of the following materials: steel, aluminum, or titanium alloy. Thus, in this embodiment, by setting the materials of the support structure 27, the first wall 50, and the pressure relief mechanism 213 to one of the following materials—steel, aluminum, or titanium alloy—the welding connection between the support structure 27, the first wall 50, and the pressure relief mechanism 213 is facilitated, improving the processing and manufacturing efficiency of the battery cell 20 while reducing processing and manufacturing costs.

[0190] In some implementations, the support structure 27, the first wall 50, and the pressure relief mechanism 213 are all made of one of the following materials: steel, aluminum, or titanium alloy. Thus, in this embodiment, by using steel, aluminum, or titanium alloy for the support structure 27, the first wall 50, and the pressure relief mechanism 213, the welding connection between them is facilitated, further improving the processing and manufacturing efficiency of the battery cell 20, while simultaneously reducing processing and manufacturing costs.

[0191] Referring again to Figures 1 to 13 above, this application embodiment provides a battery cell 20, which includes: an electrode assembly 22, a housing 211, a pressure relief mechanism 213, and a support structure 27. The housing 211 has an internal cavity in which the electrode assembly 22 is housed. The housing 211 has a first wall 50, and the first wall 50 is provided with a pressure relief hole 60, which communicates with the housing cavity. The pressure relief hole 60 includes a first hole 610 and a second hole 620 distributed in a stepped manner. One end of 610 is formed on the surface of the first wall 50 facing the electrode assembly 22. The second hole 620 is located on the side of the first hole 610 away from the receiving cavity. The pressure relief mechanism 213 is received in the first hole 610 and connected to the housing 211. The support structure 27 is fixed to the side of the first wall 50 facing the electrode assembly 22. The pressure relief mechanism 213 is located on the side of the support structure 27 away from the electrode assembly 22. The pressure relief mechanism 213 is welded to at least one of the support structure 27 and the first wall 50. The pressure relief mechanism 213, the support structure 27, and the first wall 50 are connected by the same solder joint. On a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the support structure 27 covers the orthographic projection of the solder joint. The side of the pressure relief mechanism 213 near the inner wall of the first hole 610 abuts against the inner wall of the first hole 610. The battery cell 20 also includes a base plate 23, which is housed in the receiving cavity and located between the electrode assembly 22 and the first wall 50. The base plate 23 supports the electrode assembly 22. The base plate 23 includes a main body 231 and a protrusion 232. The side of the protrusion 232 facing away from the first wall 50 is connected to the main body 231, and the side of the protrusion 232 facing the first wall 50 is attached to the first wall 50. In a plane perpendicular to the thickness direction of the first wall 50, the orthographic projection of the protrusion 232 does not overlap with the orthographic projection of the support structure 27, and the orthographic projection of the protrusion 232 does not overlap with at least a portion of the orthographic projection of the pressure relief mechanism 213. In the thickness direction of the first wall 50, the distance H1 between the main body 231 and the first wall 50 and the dimension H2 of the support structure 27 satisfy: 0mm < H1 - H2 ≤ 5mm.

[0192] This application also provides a battery device 10, which includes a plurality of battery cells 20, wherein the battery cells 20 are the battery cells 20 in any of the above embodiments.

[0193] This application also provides an electrical device, including the battery device 10 in any of the above embodiments, which is used to provide electrical energy to the electrical device. Specifically, the electrical device can be the vehicle 1 shown in Figure 1 above, or any electrical device using the battery device 10.

[0194] This application also provides an energy storage device, including the battery device 10 in any of the above embodiments, the battery device 10 being used to store electrical energy for the energy storage device.

[0195] Although this application has been described with reference to the above embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the embodiments of this application. In particular, the technical features mentioned in the various embodiments can be combined in any way, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The battery cell comprises: an electrode assembly; a housing having an accommodation cavity formed inside, the electrode assembly being accommodated in the accommodation cavity, the housing having a first wall provided with a pressure relief hole communicating with the accommodation cavity, the pressure relief hole comprising a first hole and a second hole distributed in a stepped manner, one end of the first hole being formed on a surface of the first wall on a side facing the electrode assembly, the second hole being located on a side of the first hole away from the accommodation cavity; a pressure relief mechanism accommodated in the first hole and connected to the housing; a support structure fixed to a side of the first wall facing the electrode assembly, the pressure relief mechanism being located on a side of the support structure away from the electrode assembly, the pressure relief mechanism being welded to at least one of the support structure and the first wall.

2. The battery cell of claim 1, wherein, The pressure relief mechanism, the support structure and the first wall are connected by the same welding mark, and in a plane perpendicular to the thickness direction of the first wall, the orthographic projection of the support structure covers the orthographic projection of the welding mark.

3. The battery cell according to claim 1 or 2, characterized in that, A side of the pressure relief mechanism close to the inner wall of the first hole abuts against the inner wall of the first hole.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The surface of the support structure facing the first wall, the surface of the pressure relief mechanism facing the electrode assembly and the surface of the first wall facing the electrode assembly are in the same plane.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The battery cell further comprises a bottom support plate accommodated in the accommodation cavity and located between the electrode assembly and the first wall, the bottom support plate being used to support the electrode assembly.

6. The battery cell of claim 5, wherein, The bottom support plate comprises a main body portion and a protruding portion, a side of the protruding portion away from the first wall being connected to the main body portion, a side of the protruding portion facing the first wall being attached to the first wall, and an exhaust passage communicating with the pressure relief mechanism being formed between the main body portion and the first wall.

7. The battery cell of claim 6, wherein, In a plane perpendicular to the thickness direction of the first wall, the orthographic projection of the protruding portion does not overlap with the orthographic projection of the support structure, and the orthographic projection of the protruding portion does not overlap with the orthographic projection of the pressure relief mechanism.

8. The battery cell according to claim 6 or 7, characterized in that In the thickness direction of the first wall, the distance H1 between the main body portion and the first wall is greater than the size H2 of the support structure.

9. The battery cell of claim 8, wherein, In the thickness direction of the first wall, the distance H1 between the main body portion and the first wall and the size H2 of the support structure satisfy: 0mm < H1-H2 ≤ 5mm.

10. The battery cell according to claim 8 or 9, characterized in that, The size H2 of the support structure in the thickness direction of the first wall is greater than or equal to 0.3mm.

11. The battery cell of any one of claims 1 to 10, wherein, The thickness D1 of the first wall satisfies: 0.6mm ≤ D1 ≤ 3mm.

12. The battery cell of claim 11, wherein, The thickness D1 of the first wall satisfies: 0.8mm ≤ D1 ≤ 1.5mm.

13. The battery cell of any one of claims 1 to 10, wherein, The pressure relief hole further comprises a third hole located on a side of the second hole away from the first hole, and the battery cell further comprises a protection member accommodated in the third hole and connected to the housing, in a plane perpendicular to the thickness direction of the first wall, the orthographic projection of the protection member covers the orthographic projection of the pressure relief mechanism.

14. The battery cell of claim 13, wherein, From the first hole to the third hole, the size of the pressure relief hole in the thickness direction perpendicular to the first wall gradually increases.

15. The battery cell according to claim 13 or 14, characterized in that The thickness D2 of the first wall satisfies: 0.8mm≤D2≤3.2mm.

16. The battery cell of claim 15, wherein, The thickness D2 of the first wall satisfies: 1mm≤D2≤1.7mm.

17. The battery cell of any one of claims 1 to 16, wherein, The support structure is arranged around the outer periphery of the pressure relief mechanism.

18. The battery cell of claim 17, wherein, The support structure is an annular structure, and an inner ring of the annular structure encircles the pressure relief hole.

19. The battery cell of claim 18, wherein, The width D3 of the support structure satisfies: 0.5mm≤D3≤10mm.

20. The battery cell of any one of claims 1-19, wherein, The material of the support structure, the first wall and the pressure relief mechanism is one of: steel, aluminum or titanium alloy.

21. The battery cell of any one of claims 1-20, wherein, The material of the support structure, the first wall and the pressure relief mechanism is one of: steel, aluminum or titanium alloy.

22. A battery device, characterized by Comprising: A plurality of battery cells, the battery cell being as claimed in any one of claims 1 to 21.

23. An electrical device, comprising: Comprising the battery device as claimed in claim 22, the battery device being used to provide electric energy for the electric equipment.

24. An energy storage device, comprising: Comprising the battery device as claimed in claim 22, the battery device being used to store electric energy for the energy storage equipment.

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