Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, a pressure relief mechanism and an electrode assembly. The shell has a first wall, and the pressure relief mechanism is arranged on the first wall. The first wall comprises a first part and a second part. The thickness of the first part is greater than the thickness of the second part. The first part is located on the side of the pressure relief mechanism and is connected with the pressure relief mechanism. The first direction intersects the thickness of the first wall. The electrode assembly is accommodated in the shell. The battery monomer provided by the application is beneficial to delaying the time for the complete melting of the first part connected with the pressure relief mechanism, reducing the risk of the emission in the battery monomer being emitted to the adjacent battery monomer through the first wall which is completely melted, thereby causing a larger range of thermal runaway, and thus the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery cell technology, in addition to improving the performance of battery cells, their reliability is also a crucial consideration. Therefore, improving the reliability of battery cells is a continuous challenge in battery cell technology. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device, which helps to improve the reliability of the battery cell.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, the battery cell provided in the embodiments of this application includes a casing, a pressure relief mechanism, and an electrode assembly. The casing has a first wall, and the pressure relief mechanism is disposed on the first wall. The first wall includes a first part and a second part, the thickness of the first part being greater than the thickness of the second part. The first part is located on the side of the pressure relief mechanism and connected to the pressure relief mechanism, and a first direction intersects with the thickness of the first wall. The electrode assembly is housed within the casing.

[0007] The battery cell provided in this application embodiment has a pressure relief mechanism located on the first wall of the casing. The first wall includes a first part and a second part, with the thickness of the first part being greater than that of the second part. The first part is connected to the side of the pressure relief mechanism. In the event of thermal runaway in the battery cell, this helps to delay the time when the first part connected to the pressure relief mechanism completely melts, reducing the risk of emissions from inside the battery cell being ejected to adjacent battery cells through the completely melted first wall, thereby causing a wider range of thermal runaway. This helps to improve the reliability of the battery cell.

[0008] According to some embodiments of this application, the first wall includes two second parts, which are respectively disposed on both sides of the pressure relief mechanism along the first direction and are respectively connected to the pressure relief mechanism. The first direction intersects with the thickness of the first wall.

[0009] In the above scheme, it is beneficial to delay the risk of partial complete melting of the first wall on both sides of the pressure relief mechanism along the first direction, further beneficial to reduce the risk of emissions inside the battery cell being ejected to adjacent battery cells via the first wall on both sides of the pressure relief mechanism along the first direction, and further beneficial to reduce the risk of further spread of thermal runaway of the battery cell.

[0010] According to some embodiments of this application, the dimension of the first wall along the first direction is smaller than the dimension along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other.

[0011] In the above scheme, in the event of thermal runaway of a single battery cell, it is beneficial to increase the time for the first wall along the path where the pressure relief mechanism is closer to the adjacent battery cell to completely melt. This reduces the risk of high-temperature, high-pressure emissions from inside the battery cell being ejected to adjacent battery cells via the completely melted first wall, thereby preventing a wider range of thermal runaway. It also helps to reduce the weight of the battery cell, thus increasing its energy density.

[0012] According to some embodiments of this application, along the second direction, the first part does not extend beyond the pressure relief mechanism, and the first direction, the second direction, and the thickness direction are perpendicular to each other.

[0013] The above scheme is beneficial in reducing the risk of further spread of the pressure relief mechanism, while also reducing the size of the second part to reduce the weight of the battery cell, which in turn helps to improve the energy density of the battery cell.

[0014] According to some embodiments of this application, along the first direction, the minimum distance d between the edge of the first part and the edge of the first wall satisfies: 1mm≤d≤2mm.

[0015] In the above scheme, by setting 1mm≤d≤2mm, it is beneficial to increase the time for the first part to fully melt, reduce the risk of internal emissions being ejected from the first wall to adjacent battery cells and thus causing a wider range of thermal runaway in the event of thermal runaway of a battery cell, and at the same time, it is beneficial to reduce the manufacturing difficulty of the battery cells.

[0016] According to some embodiments of this application, the battery cell further includes electrode terminals, which are disposed in the second part of the first wall.

[0017] In the above scheme, by setting up a first part, in the event of thermal runaway of a battery cell, the melting time of the area of ​​the first wall where the first part is located is delayed, which helps to reduce the risk of emissions from inside the battery cell being ejected to the busbar through the area of ​​the melted first wall next to the pressure relief mechanism, thereby improving the reliability of the battery device in which the battery cell is located.

[0018] According to some embodiments of this application, the outer surface of the first part does not extend beyond the outer surface of the electrode terminal.

[0019] The above scheme helps to reduce the risk of interference between the first part and related structures such as the busbar in the battery device, and facilitates the smooth progress of the battery device assembly process.

[0020] According to some embodiments of this application, the first part protrudes relative to the second part toward the side of the first wall away from the electrode assembly.

[0021] In the above scheme, by setting the first part to protrude from the side of the first wall away from the electrode assembly relative to the second part, it is beneficial to improve the energy density of the battery cell and simplify the manufacturing process of the battery cell.

[0022] According to some embodiments of this application, the protrusion distance h of the first part relative to the second part satisfies: 1mm≤h≤3mm.

[0023] In the above scheme, by setting 1mm≤h≤3mm, it is beneficial to reduce the risk of further spread of thermal runaway of battery cells, and also to reduce the risk of interference between the first part and other structures in the battery device.

[0024] Secondly, the battery device provided in the embodiments of this application includes the battery cell provided in any of the above embodiments.

[0025] The battery device provided in this application has the same technical effect as the battery cell provided in any of the above embodiments, and will not be described again here.

[0026] According to some embodiments of this application, the battery cell further includes electrode terminals, which are disposed in the second part. The battery device also includes a busbar that electrically connects the electrode terminals of two adjacent battery cells.

[0027] In the above scheme, by setting up a first part, in the event of thermal runaway of a battery cell, the time for the area of ​​the first wall where the first part is located to completely melt is delayed. This helps to reduce the risk of emissions from inside the battery cell being ejected into the busbar through the area of ​​the melted first wall next to the pressure relief mechanism, thereby improving the reliability of the battery device.

[0028] According to some embodiments of this application, the dimension of the first wall along the first direction is smaller than the dimension along the second direction, and the first direction, the second direction, and the thickness direction of the first wall are perpendicular to each other. The first part is disposed on both sides of the pressure relief mechanism along the first direction. The battery device includes multiple battery cell assemblies, each battery cell assembly including multiple battery cells arranged along the second direction, and the multiple battery cell assemblies arranged along the first direction. Multiple battery cells in the same battery cell assembly are connected in series, and multiple battery cell assemblies are connected in parallel.

[0029] In the above scheme, by placing the first part on both sides of the pressure relief mechanism along the first direction, in the event of thermal runaway of any battery cell, it is beneficial to reduce the risk of thermal runaway and high voltage ignition inside the battery device caused by the high voltage difference of the emission on another battery cell adjacent to it along the first direction, which may lead to a wider range of thermal runaway and high voltage ignition inside the battery device, thereby further improving the reliability of the battery device.

[0030] Thirdly, the electrical device provided in the embodiments of this application includes the battery device provided in any of the above embodiments, and the battery device is used to provide electrical energy.

[0031] The electrical device provided in this application embodiment has the same technical effect as the battery device provided in this application embodiment, and will not be described again here.

[0032] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the vehicle structure provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0036] Figure 3 This is a schematic diagram of the structure of a battery cell assembly in a battery device provided in an embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell provided in an embodiment of this application;

[0038] Figure 5 This is a top view of a portion of the structure of a battery cell provided in an embodiment of this application;

[0039] Figure 6 This is a front view of a portion of the structure of a battery cell provided in an embodiment of this application;

[0040] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure along AA.

[0041] The accompanying drawings are not necessarily drawn to scale.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1-Vehicle; 1a-Motor; 1b-Controller;

[0044] 10 - Battery assembly; 11 - Housing; 111 - First sub-housing; 112 - Second sub-housing;

[0045] 20-Battery cell module;

[0046] 30-Battery cell; 31-Casing; 311-Housing; 312-End cap; 313-First wall; 3131-First part; 3132-Second part; 32-Electrode assembly; 321-Electrode body; 322-Taper; 33-Electrode terminal; 34-Pressure relief mechanism;

[0047] 40 - Busbar;

[0048] X - First direction; Y - Second direction; Z - Thickness direction. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0051] 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.

[0052] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0054] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0055] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0056] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0057] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0058] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0059] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0060] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0061] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0062] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0063] The battery cell may be, but is not limited to, lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc.

[0064] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0065] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0066] 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.

[0067] 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 made of stainless steel, copper, aluminum, carbon electrodes, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector 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.).

[0068] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for battery cells may also be used.

[0069] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, copper, aluminum, carbon electrode, carbon, nickel, or titanium, etc.

[0071] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0072] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0073] In some embodiments, the diaphragm 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.

[0074] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0075] In some embodiments, the membrane is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0076] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0077] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0078] In some embodiments, the housing includes an end cap and a shell, the shell having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The shell may have one or more openings. The end cap may also be provided one or more times.

[0079] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0080] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0081] As an example, the 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. There are no particular limitations in the embodiments of this application.

[0082] During cyclic operation, battery cells inevitably generate heat. Under normal circumstances, this heat is dissipated into the environment, maintaining the battery cell within its normal operating temperature range. However, if a battery cell malfunctions, it risks thermal runaway. Once thermal runaway occurs, the internal temperature and pressure of the battery cell continue to rise. When the internal pressure reaches the actuation pressure of the pressure relief mechanism, the mechanism activates, allowing the high-temperature emissions from inside the battery cell to be discharged.

[0083] However, in related technologies, in the event of thermal runaway of a battery cell, the internal temperature of the battery cell is high, and the high-temperature emissions accumulate near the pressure relief mechanism, causing the wall of the battery cell's casing near the pressure relief mechanism to melt. When the casing wall is completely melted, the high-temperature and high-pressure emissions are ejected from the completely melted casing wall near the pressure relief mechanism to the wall of the adjacent battery cell, thereby causing thermal runaway of the adjacent battery cell. This seriously affects the reliability of the battery cell.

[0084] In view of this, embodiments of this application provide a battery cell including a casing, a pressure relief mechanism, and an electrode assembly. The casing has a first wall, and the pressure relief mechanism is disposed on the first wall. The first wall includes a first part and a second part, the thickness of the first part being greater than the thickness of the second part. The first part is located on the side of the pressure relief mechanism and connected to the pressure relief mechanism. A first direction X intersects with the thickness of the first wall. The electrode assembly is housed within the casing.

[0085] The battery cell provided in this application embodiment has a pressure relief mechanism located on the first wall of the casing. The first wall includes a first part and a second part, with the thickness of the first part being greater than that of the second part. The first part is connected to the side of the pressure relief mechanism. In the event of thermal runaway in the battery cell, this helps to delay the time when the first part connected to the pressure relief mechanism completely melts, reducing the risk of emissions from inside the battery cell being ejected to adjacent battery cells through the completely melted first wall, thereby causing a wider range of thermal runaway. This helps to improve the reliability of the battery cell.

[0086] The technical solutions described in the embodiments of this application are applicable to battery cells, battery devices including battery cells, and electrical devices using battery devices.

[0087] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the battery device disclosed in this application.

[0088] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric motorcycles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0089] For ease of explanation, the following embodiments will be described using a vehicle 1 as an example of an electrical device according to an embodiment of this application.

[0090] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1 provided in an embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 10 is installed inside vehicle 1, and the battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, the battery device 10 can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 1.

[0091] The vehicle 1 may also include a controller 1b and a motor 1a. The controller 1b is used to control the battery device 10 to supply power to the motor 1a, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0092] In some embodiments 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 for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0093] Please refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the structure of the battery device 10 provided in the embodiments of this application. Figure 3 This is a schematic diagram of the structure of the battery cell assembly 20 in the battery device 10 provided in this application embodiment. The battery device 10 includes a housing 11 and battery cells 30, with the battery cells 30 housed within the housing 11. The housing 11 provides a space for accommodating the battery cells 30, and the housing 11 can adopt various structures. In some embodiments, the housing 11 may include a first sub-housing 111 and a second sub-housing 112, which overlap each other, and together define a space for accommodating the battery cells 30. The second sub-box 112 can be a hollow structure with one end open, and the first sub-box 111 can be a plate-like structure. The first sub-box 111 covers the opening side of the second sub-box 112 so that the first sub-box 111 and the second sub-box 112 together define the accommodating space. Alternatively, the first sub-box 111 and the second sub-box 112 can both be hollow structures with one side open, and the opening side of the first sub-box 111 covers the opening side of the second sub-box 112.

[0094] In the battery device 10, there can be multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 30 are connected in both series and parallel configurations. Multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 30 is housed within the housing 11. Alternatively, the battery device 10 can also consist of multiple battery cells 30 first connected in series, parallel, or in a mixed manner to form a battery cell assembly 20, and then the multiple battery cell assemblies 20 are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 11. The battery device 10 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 30.

[0095] Among them, the battery cell 30 can be a secondary battery or a primary battery; the battery cell 30 can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0096] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the exploded structure of a battery cell 30 provided in an embodiment of this application. Figure 4 As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and electrode terminals 33. The housing 31 includes a casing 311 and an end cap 312. The casing 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0097] The housing 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 311 and the end cap 312 can be independent components. The housing 311 can have various shapes and sizes. Specifically, the shape of the housing 311 can be determined according to the specific shape and size of the electrode assembly 32. The housing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0098] End cap 312 refers to a component that covers the opening of housing 311 to isolate the internal environment of battery cell 30 from the external environment. The shape of end cap 312 can be adapted to the shape of housing 311 to fit it. Optionally, end cap 312 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 312 is not easily deformed under pressure and impact, giving battery cell 30 higher structural strength and improved reliability. Functional components such as electrode terminals 33 can be provided on end cap 312. Electrode terminals 33 can be used for electrical connection with electrode assembly 32 to output or input electrical energy to battery cell 30. The material of end cap 312 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure may be provided on the inner side of the end cap 312. The insulating structure can be used to isolate the electrical connection components within the housing 311 from the end cap 312 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0099] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The housing 311 may contain one or more electrode assemblies 32. The electrode assembly 32 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates to separate them and prevent internal short circuits. The portions of the positive and negative electrode plates containing active material constitute the electrode body 321 of the electrode assembly 32, while the portions of the positive and negative electrode plates without active material each constitute a tab 322. The positive and negative tabs may be located together at one end of the electrode body 321 or separately at both ends of the electrode body 321. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs 322 connect to the electrode terminals 33 to form a current loop.

[0100] Firstly, such as Figure 4 As shown in the illustration, this application provides a battery cell 30 including a housing 31, a pressure relief mechanism 34, and an electrode assembly 32. The housing 31 has a first wall 313, and the pressure relief mechanism 34 is disposed on the first wall 313. The first wall 313 includes a first part 3131 and a second part 3132. The thickness of the first part 3131 is greater than the thickness of the second part 3132. The first part 3131 is located on the side of the pressure relief mechanism 34 and is connected to the pressure relief mechanism 34. The first direction X intersects with the thickness of the first wall 313. The electrode assembly 32 is accommodated within the housing 31.

[0101] The housing 31 has a first wall 313. The housing 31 may include a housing 311 and an end cap 312. The end cap 312 covers the housing 311. Optionally, the first wall 313 may be part of the housing 311, or the first wall 313 may be part of the end cap 312.

[0102] The battery cell 30 may also include an electrode terminal 33, which may be disposed on the second part 3132 of the first wall 313, or the electrode terminal 33 may also be disposed on other wall parts of the housing 31. For example, the electrode terminal 33 may be disposed on the wall part of the housing 31 opposite to the first wall 313.

[0103] The pressure relief mechanism 34 can be integrally formed with the first wall 313. For example, grooves can be made on the first wall 313 to form a weak structure, which serves as the pressure relief mechanism 34. Alternatively, the pressure relief mechanism 34 can be separately formed from and connected to the first wall 313. For example, the pressure relief mechanism 34 can be welded to the first wall 313 or connected via other components. Optionally, the pressure relief mechanism 34 can take the form of an explosion-proof valve, a balancing valve, a gas valve, a pressure relief valve, or a safety valve.

[0104] The emissions from the battery cell 30 mentioned in this application 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.

[0105] The first wall 313 includes a first part 3131 and a second part 3132. Optionally, the first wall 313 may include one, two, three or more first parts 3131. The first parts 3131 may be arranged around the pressure relief mechanism 34, or the first parts 3131 may be located on a portion of the periphery of the pressure relief mechanism 34. For example, two first parts 3131 may be provided on both sides of the pressure relief mechanism 34 along the length direction of the first wall 313, or two first parts 3131 may be provided on both sides of the pressure relief mechanism 34 along the width direction of the first wall 313. Of course, the first wall 313 may also be provided on both sides of the pressure relief mechanism 34 along the length direction of the first wall 313 and on both sides along the width direction.

[0106] Optionally, the first part 3131 and the second part 3132 can be integrally formed, or they can be formed separately and then connected together, depending on actual needs.

[0107] If the thickness of the first part 3131 is greater than the thickness of the second part 3132, then the first part 3131 protrudes relative to the second part 3132 along the thickness direction Z of the first wall 313. Optionally, the first part 3131 may protrude toward the electrode assembly 32 relative to the second part 3132, or the first part 3131 may protrude away from the electrode assembly 32 relative to the second part 3132. Of course, the first part 3131 may also be configured to protrude both toward the electrode assembly 32 and away from the electrode assembly 32 relative to the second part 3132.

[0108] Since the thickness of the first part 3131 is greater than that of the second part 3132, the time it takes for the first part 3131 to completely melt during the melting process will be longer than that for the second part 3132. In the event of thermal runaway of the battery cell 30, the pressure relief mechanism 34 is activated. As the high-temperature emissions inside the battery cell 30 flow through the pressure relief mechanism 34, they heat the first part 3131 adjacent to the pressure relief mechanism 34. Because the first part 3131 is thicker, during the melting of the first part 3131, the high-temperature and high-pressure gas inside the battery cell 30 is continuously discharged from the pressure relief mechanism 34, thus reducing the pressure and temperature inside the battery cell 30. This reduces the risk of the first part 3131 completely melting, and further reduces the risk of emissions from the area where the first part 3131, adjacent to the pressure relief mechanism 34, is located to other adjacent battery cells 30 when the battery cell 30 experiences thermal runaway. This helps to reduce the risk of further spread of thermal runaway of the battery cell 30.

[0109] Furthermore, by only making the thickness of the first part 3131 greater than the thickness of the second part 3132, instead of thickening the entire first wall 313, the risk of thermal runaway in the battery cell 30 is reduced, which helps to reduce the weight of the battery cell 30 and thus improves its energy density. Moreover, during the production of the battery cell 30, other structures can be incorporated into the first wall 313, which can be placed in the second part 3132 without altering the structural form of the other structures, thus facilitating the fabrication of the battery cell 30.

[0110] The battery cell 30 provided in this application embodiment has a pressure relief mechanism 34 disposed on the first wall 313 of the housing 31. The first wall 313 is provided to include a first part 3131 and a second part 3132. The thickness of the first part 3131 is greater than the thickness of the second part 3132. The first part 3131 is connected to the side of the pressure relief mechanism 34. In the event of thermal runaway of the battery cell 30, it is beneficial to delay the time when the first part 3131 connected to the pressure relief mechanism 34 completely melts. This reduces the risk of emissions from inside the battery cell 30 being ejected to adjacent battery cells 30 through the completely melted first wall 313, thereby causing a wider range of thermal runaway. This is beneficial to improve the reliability of the battery cell 30.

[0111] In some embodiments, such as Figure 4 and Figure 5 As shown, the first wall 313 includes two second parts 3132, which are respectively disposed on both sides of the pressure relief mechanism 34 along the first direction X and are respectively connected to the pressure relief mechanism 34. The first direction X intersects with the thickness of the first wall 313.

[0112] Two second parts 3132 are respectively disposed on both sides of the pressure relief mechanism 34 along the first direction X. For the battery cell 30 with the first wall 313 being square, the first direction X can optionally be the length direction of the first wall 313, that is, the direction in which the size of the first wall 313 is larger, or the first direction X can be the width direction of the first wall 313, that is, the direction in which the size of the first wall 313 is smaller.

[0113] The two first parts 3131 are respectively connected to the two sides of the pressure relief mechanism 34 along the first direction X. In the event of a runaway battery cell 30, the high-temperature and high-pressure emissions inside the battery cell 30 are discharged through the pressure relief mechanism 34 and heat the first wall 313. Since the pressure relief mechanism 34 is provided with the first parts 3131 on both sides along the first direction X, it helps to delay the risk of complete melting of the first wall 313 on both sides of the pressure relief mechanism 34 along the first direction X. This further helps to reduce the risk of the emissions inside the battery cell 30 being sprayed to adjacent battery cells 30 through the first wall 313 on both sides of the pressure relief mechanism 34 along the first direction X. This further helps to reduce the risk of the thermal runaway of the battery cell 30 spreading further.

[0114] In some embodiments, such as Figure 4 and Figure 5 As shown, the dimension of the first wall 313 along the first direction X is smaller than the dimension along the second direction Y, and the first direction X, the second direction Y and the thickness direction Z are perpendicular to each other.

[0115] If the dimension of the first wall 313 along the first direction X is smaller than the dimension along the second direction Y, then in the event of thermal runaway of the battery cell 30, the distance between the pressure relief mechanism 34 and the adjacent battery cell 30 along the first direction X is shorter. Since the first part 3131 is provided on both sides of the pressure relief mechanism 34 along the first direction X, and the time for the first part 3131 to completely melt is delayed, the time for the first wall 313 on the smaller path between the pressure relief mechanism 34 and the adjacent battery cell 30 to partially melt is also delayed.

[0116] In addition, after the portion of the first wall 313 located on both sides of the pressure relief mechanism 34 along the smaller dimension direction, i.e. the first direction X, is completely melted, the emitted material is ejected from both sides of the pressure relief mechanism 34 along the first direction X, and is most likely to be ejected onto the adjacent battery cell 30. Therefore, by setting the first part 3131 on both sides of the pressure relief mechanism 34 along the first direction X, i.e., determining the position of the first part 3131 more accurately, the risk of thermal runaway of the battery cell 30 is reduced, while also helping to reduce the weight of the battery cell 30 and increase the energy density of the battery cell 30.

[0117] In the event of thermal runaway of the battery cell 30, this design allows for a longer period of time for the first wall 313 along the path between the pressure relief mechanism 34 and adjacent battery cells 30 to completely melt. This significantly reduces the risk of high-temperature, high-pressure emissions from inside the battery cell 30 being ejected into adjacent battery cells via the fully melted first wall 313, thus preventing a wider-ranging thermal runaway. Furthermore, this design helps reduce the weight of the battery cell 30, thereby increasing its energy density.

[0118] In some embodiments, such as Figure 4 Figure 5As shown, in the second direction Y, the first part 3131 is not set beyond the pressure relief mechanism 34, and the first direction X, the second direction Y and the thickness direction Z are perpendicular to each other.

[0119] If the first part 3131 does not extend beyond the pressure relief mechanism 34 along the second direction Y, then the extension direction of the first part 3131 along the second direction Y can be flush with the pressure relief mechanism 34, or the extension distance of the first part 3131 is shorter than the extension distance of the pressure relief mechanism 34 along the second direction Y.

[0120] After the battery cell 30 thermally runs away, the pressure relief mechanism 34 is activated, and the discharge inside the battery cell 30 is discharged through the pressure relief mechanism 34. The discharge inside the battery cell 30 accumulates near the pressure relief mechanism 34 and heats a part of the first wall 313 near the pressure relief mechanism 34. Therefore, the part of the first wall 313 with a greater risk of melting is the area adjacent to the pressure relief mechanism 34.

[0121] Therefore, by setting the second part 3132 to not exceed the pressure relief mechanism 34 along the second direction Y, it is beneficial to reduce the risk of further spread of the pressure relief mechanism 34, and also to reduce the size of the second part 3132, thereby reducing the weight of the battery cell 30, and further improving the energy density of the battery cell 30.

[0122] In some embodiments, such as Figure 5 As shown, the minimum distance d between the edge of the first part 3131 and the edge of the first wall 313 satisfies: 1mm≤d≤2mm.

[0123] Optionally, d can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2mm.

[0124] It is understandable that the larger the distance d is to a certain extent, the easier it is to prepare and form the protrusion, while the smaller the distance d is to a certain extent, the more beneficial it is to increase the size of the first part 3131 along the first direction X, which in turn helps to delay the time for the first part 3131 to completely melt, so as to reduce the risk of further spread of thermal runaway of the battery cell 30.

[0125] Therefore, after systematic analysis and long-term practice, the inventors discovered that by setting 1mm≤d≤2mm, it is beneficial to increase the time for the first part 3131 to completely melt, reduce the risk of internal emissions being ejected from the first wall 313 to adjacent battery cells 30 and thus causing a wider range of thermal runaway in the event of thermal runaway of the battery cell 30, and at the same time, it is also beneficial to reduce the manufacturing difficulty of the battery cell 30.

[0126] In some embodiments, such as Figure 4 and Figure 5 As shown, electrode terminal 33 is disposed in the second part 3132 of the first wall 313.

[0127] With the electrode terminal 33 located on the first wall 313, after the battery cell 30 is assembled into the battery device 10, it is electrically connected to the electrode terminal 33 of the adjacent battery cell 30 through the busbar 40, so as to realize the series or parallel connection between different battery cells 30.

[0128] Thus, in the event of thermal runaway of the battery cell 30, if the internal emissions are ejected through part of the first wall 313 melted on the side of the pressure relief mechanism 34, there is a high risk of them being ejected into the busbar 40. Since there is a strong current passing through the busbar 40, once the high-temperature emissions are ejected into the busbar 40, there is a high risk of high-voltage arcing.

[0129] In this embodiment, by setting the first part 3131, the melting time of the area of ​​the first wall 313 where the first part 3131 is located is delayed in the event of thermal runaway of the battery cell 30. This helps to reduce the risk that the emissions inside the battery cell 30 will be ejected into the busbar 40 through the area of ​​the melted first wall 313 next to the pressure relief mechanism 34, thereby improving the reliability of the battery device 10 where the battery cell 30 is located.

[0130] In some embodiments, such as Figure 6 and Figure 7 As shown, the outer surface of the first part 3131 does not extend beyond the outer surface of the electrode terminal 33.

[0131] During the assembly of the battery cells 30 into the battery device 10, the electrode terminals 33 of different battery cells 30 need to be connected through the busbar 40 to realize the series or parallel connection of different battery cells 30.

[0132] By setting the outer surface of the first part 3131 to extend beyond the outer surface of the electrode terminal 33, it is beneficial to reduce the risk of interference between the first part 3131 and related structures such as the busbar 40 in the battery device 10, and facilitate the smooth progress of the assembly process of the battery device 10.

[0133] In some embodiments, such as Figure 6 and Figure 7 As shown, the first part 3131 protrudes from the side of the first wall 313 away from the electrode assembly 32 relative to the second part 3132.

[0134] The side of the first wall 313 facing the electrode assembly 32 typically requires an insulating material such as plastic to achieve insulation between the first wall 313 and the electrode assembly 32. By configuring the first part 3131 to protrude relative to the second part 3132 on the side of the first wall 313 facing away from the electrode assembly 32, the side of the first wall 313 facing the electrode assembly 32 can be made smoother, facilitating the installation of the insulating material such as plastic on this side. Furthermore, the portion of the first part 3131 extending beyond the second part 3132 is located on the side of the first wall 313 facing away from the electrode assembly 32, thus not occupying internal space within the battery cell 30.

[0135] Therefore, by setting the first part 3131 to protrude relative to the second part 3132 toward the side of the first wall 313 away from the electrode assembly 32, it is beneficial to improve the energy density of the battery cell 30 and to simplify the manufacturing process of the battery cell 30.

[0136] In some embodiments, such as Figure 7 As shown, the protrusion distance h of the first part 3131 relative to the second part 3132 satisfies: 1mm≤h≤3mm.

[0137] Optionally, h can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3mm, etc.

[0138] Understandably, a larger value of h, to a certain extent, is more conducive to delaying the complete melting of the first part 3131 in the event of thermal runaway of the battery cell 30, and thus reduces the risk of further spread of thermal runaway of the battery cell 30. Conversely, a smaller value of h, to a certain extent, is more conducive to reducing the risk of interference between the first part 3131 and other structures during the assembly of the battery cell 30 into the battery device 10.

[0139] Therefore, after systematic analysis and long-term practice, the inventors found that by setting 1mm≤h≤3mm, it is beneficial to reduce the risk of further spread of thermal runaway of the battery cell 30, and also to reduce the risk of interference between the first part 3131 and other structures in the battery device 10.

[0140] Secondly, the battery device 10 provided in the embodiments of this application includes the battery cell 30 provided in any of the above embodiments.

[0141] The battery device 10 provided in this application embodiment has the same technical effect as the battery cell 30 provided in any of the above embodiments, and will not be described again here.

[0142] In some embodiments, such as Figure 2 and Figure 3 As shown, the battery cell 30 also includes an electrode terminal 33, which is located in the second part 3132. The battery device 10 also includes a busbar 40, which electrically connects the electrode terminals 33 of two adjacent battery cells 30.

[0143] Thus, the battery cells 30 are electrically connected to the electrode terminals 33 through the busbar 40, so as to realize the series or parallel connection of different battery cells 30.

[0144] Thus, in the event of thermal runaway of any battery cell 30, if the internal emissions are ejected through a portion of the first wall 313 melted on the side of the pressure relief mechanism 34, there is a significant risk that they will be ejected onto the busbar 40. Since a strong current flows through the busbar 40, if the high-temperature emissions are ejected onto the busbar 40, it will bring a high risk of high-voltage arcing to the battery device 10.

[0145] In this embodiment of the application, by setting the first part 3131, the time for the area of ​​the first wall 313 where the first part 3131 is located to completely melt is delayed in the event of thermal runaway of the battery cell 30. This helps to reduce the risk that the emissions inside the battery cell 30 will be ejected into the busbar 40 through the area of ​​the melted first wall 313 next to the pressure relief mechanism 34, thereby improving the reliability of the battery device 10.

[0146] In some embodiments, the dimension of the first wall 313 along the first direction X is smaller than its dimension along the second direction Y. The first direction X, the second direction Y, and the thickness direction Z of the first wall 313 are perpendicular to each other. The first part 3131 is disposed on both sides of the pressure relief mechanism 34 along the first direction X. The battery device 10 includes a plurality of battery cell assemblies 20, each battery cell assembly 20 including a plurality of battery cells 30 arranged along the second direction Y. The plurality of battery cell assemblies 20 are arranged along the first direction X. The plurality of battery cells 30 of the same battery cell assembly 20 are connected in series, and the plurality of battery cell assemblies 20 are connected in parallel.

[0147] Since the multiple battery cells 30 of the battery cell assembly 20 are arranged along the second direction Y, and the multiple battery cells 30 of the same battery cell assembly 20 are connected in series, it is beneficial to simplify the structure of the busbar 40 and to improve the high voltage fast charging performance of the battery device 10.

[0148] Since multiple battery cell assemblies 20 are arranged along the first direction X, the battery cells 30 of two adjacent battery cell assemblies 20 along the first direction X are arranged adjacently on the side with the larger area. Multiple battery cells 30 of the same battery cell assembly 20 are connected in series. Therefore, the pressure difference between two adjacent battery cells 30 along the first direction X is large, and the spacing between the pressure relief mechanisms 34 of two adjacent battery cells 30 along the first direction X is small. Thus, if any battery cell 30 experiences thermal runaway, if the emissions inside the battery cell 30 are ejected through the pressure relief mechanism 34 along a portion of the first wall 313 on either side of the first direction X, the emissions are highly likely to erupt onto adjacent battery cells 30, posing a risk of causing a wider range of thermal runaway and a risk of causing high-voltage arcing inside the battery device 10.

[0149] Therefore, by placing the first part 3131 on both sides of the pressure relief mechanism 34 along the first direction X, in the event of thermal runaway of any battery cell 30, it is beneficial to reduce the risk of thermal runaway and high voltage ignition inside the battery device 10 on the adjacent battery cell 30 with a higher voltage difference in the emission of the emission material, thereby further improving the reliability of the battery device 10.

[0150] Thirdly, the electrical device provided in the embodiments of this application includes the battery device 10 provided in the above embodiments, and the battery device 10 is used to provide electrical energy.

[0151] The electrical device provided in this application embodiment has the same technical effect as the battery device 10 provided in this application embodiment, and will not be described again here.

[0152] In some embodiments, such as Figures 4 to 7As shown, the battery cell 30 provided in this embodiment includes a housing 31, a pressure relief mechanism 34, electrode terminals 33, and an electrode assembly 32. The housing 31 has a first wall 313, and the pressure relief mechanism 34 is disposed on the first wall 313. The first wall 313 includes a first part 3131 and a second part 3132. The thickness of the first part 3131 is greater than the thickness of the second part 3132. The first part 3131 is located on the side of the pressure relief mechanism 34 and is connected to the pressure relief mechanism 34. The electrode assembly 32 is accommodated within the housing 31. The first wall 313 includes two second parts 3132, which are respectively disposed on both sides of the pressure relief mechanism 34 along the first direction X and are respectively connected to the pressure relief mechanism 34. The first direction X intersects with the thickness of the first wall 313. The dimension of the first wall 313 along the first direction X is smaller than the dimension along the second direction Y. The first direction X, the second direction Y, and the thickness direction Z are perpendicular to each other. Along the second direction Y, the first part 3131 does not extend beyond the pressure relief mechanism 34. Along the first direction X, the minimum distance d between the edge of the first part 3131 and the edge of the first wall 313 satisfies: 1mm ≤ d ≤ 2mm. The battery cell 30 also includes an electrode terminal 33, which is disposed on the second part 3132 of the first wall 313. The outer surface of the first part 3131 does not extend beyond the outer surface of the electrode terminal 33. The first part 3131 protrudes from the side of the first wall 313 away from the electrode assembly 32 relative to the second part 3132. The protrusion distance h of the first part 3131 relative to the second part 3132 satisfies: 1mm ≤ h ≤ 3mm.

[0153] The battery cell 30 provided in this application embodiment has a pressure relief mechanism 34 disposed on the first wall 313 of the housing 31. The first wall 313 is provided to include a first part 3131 and a second part 3132. The thickness of the first part 3131 is greater than the thickness of the second part 3132. The first part 3131 is connected to the side of the pressure relief mechanism 34. In the event of thermal runaway of the battery cell 30, it is beneficial to delay the time when the first part 3131 connected to the pressure relief mechanism 34 completely melts. This reduces the risk of emissions from inside the battery cell 30 being ejected to adjacent battery cells 30 through the completely melted first wall 313, thereby causing a wider range of thermal runaway. This is beneficial to improve the reliability of the battery cell 30.

[0154] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, 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 in that, include: The outer shell has a first wall; A pressure relief mechanism is disposed on the first wall, the first wall includes a first part and a second part, the thickness of the first part is greater than the thickness of the second part, the first part is located on the side of the pressure relief mechanism and is connected to the pressure relief mechanism; The electrode assembly is housed within the housing.

2. The battery cell according to claim 1, characterized in that, The first wall includes two second parts, which are respectively disposed on both sides of the pressure relief mechanism along the first direction and are respectively connected to the pressure relief mechanism. The first direction intersects with the thickness of the first wall.

3. The battery cell according to claim 2, characterized in that, The dimension of the first wall along the first direction is smaller than the dimension along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other.

4. The battery cell according to claim 2, characterized in that, Along the second direction, the first part does not extend beyond the pressure relief mechanism, and the first direction, the second direction, and the thickness direction are perpendicular to each other.

5. The battery cell according to any one of claims 2 to 4, characterized in that, Along the first direction, the minimum distance d between the edge of the first part and the edge of the first wall satisfies: 1mm≤d≤2mm.

6. The battery cell according to any one of claims 1 to 4, characterized in that, The battery cell also includes an electrode terminal, which is disposed in the second part of the first wall.

7. The battery cell according to claim 6, characterized in that, The outer surface of the first part does not extend beyond the outer surface of the electrode terminal.

8. The battery cell according to any one of claims 1 to 4, characterized in that, The first part protrudes relative to the second part toward the side of the first wall away from the electrode assembly.

9. The battery cell according to claim 8, characterized in that, The protrusion distance h of the first part relative to the second part satisfies: 1mm≤h≤3mm.

10. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 9.

11. The battery device according to claim 10, characterized in that, The battery cell also includes electrode terminals, which are disposed in the second part; The battery device also includes a busbar that electrically connects the electrode terminals of two adjacent battery cells.

12. The battery device according to claim 11, characterized in that, The dimension of the first wall along the first direction is smaller than the dimension along the second direction. The first direction, the second direction, and the thickness direction of the first wall are perpendicular to each other. The first part is provided on both sides of the pressure relief mechanism along the first direction. The battery device includes a plurality of battery cell assemblies, each battery cell assembly including a plurality of battery cells arranged along a second direction, and the plurality of battery cell assemblies arranged along a first direction; Multiple battery cells of the same battery cell assembly are connected in series, and multiple battery cell assemblies are connected in parallel.

13. An electrical appliance, characterized in that, Includes the battery device as described in any one of claims 10 to 12, the battery device being used to provide electrical energy.

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