Battery cell, battery device, and electric device

Abstract

The present application is applicable to the technical field of batteries, and provides a battery cell, a battery device, and an electric device. The battery cell comprises a casing, a pressure relief component, and a protective member. The casing has an inner cavity and a first wall. The first wall is located at one end of the casing in a first direction. The pressure relief component is connected to the first wall. An electrode assembly is arranged in the inner cavity. The protective member is connected to the side of the pressure relief component distant from the inner cavity in the first direction. On the same projection plane perpendicular to the first direction, the orthographic projection of the protective member completely falls within the orthographic projection range of the pressure relief component. According to the battery cell, the battery device, and the electric device provided in the present application, the energy density of the battery cell can be improved.

Description

Battery cells, battery packs and electrical devices Technical Field

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

[0002] Battery cells typically have pressure relief components. To prevent these components from opening due to external impacts, protective elements are usually installed around them to provide some protection. In existing battery cells, these protective elements are generally mounted on the target component (shell or cover) that supports the pressure relief component, and they protrude from the target component. This requires the battery cell to sacrifice height space to accommodate the protective element, which is detrimental to improving the energy density of the battery cell. Summary of the Invention

[0003] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to improve the energy density of the battery cell. Technical solutions

[0004] The technical solution adopted in the embodiments of this application is:

[0005] In a first aspect, embodiments of this application provide a battery cell, comprising: a housing having an inner cavity and a first wall, the first wall being located at one end of the housing in a first direction; a pressure relief component connected to the first wall; an electrode assembly disposed within the inner cavity; and a protective member connected to the side of the pressure relief component away from the inner cavity in the first direction, wherein the orthographic projection of the protective member falls completely within the orthographic projection range of the pressure relief component on the same projection plane perpendicular to the first direction.

[0006] In related technologies, the protective component and the first wall are stacked. The edge of the protective component overlaps and connects with the first wall. Thus, the thickness of the combined structure formed by the protective component and the first wall is the sum of the thickness of the protective component and the thickness of the first wall. However, the battery cell provided in this application changes the installation method of the protective component. The protective component, which was originally stacked on the first wall, is placed at the location of the pressure relief component. Furthermore, on the same projection plane perpendicular to the first direction, the orthographic projection of the protective component completely falls within the orthographic projection range of the pressure relief component. Therefore, the thickness of the combined structure of the protective component, pressure relief component, and first wall can be less than the sum of the thicknesses of the protective component and the first wall. Thus, by using the battery cell provided in this application, the thickness of the combined structure of the protective component, pressure relief component, and first wall can be smaller. This allows for a smaller outer shell thickness and a larger inner cavity within a limited space, enabling the placement of larger electrode assemblies within the inner cavity, improving space utilization, and resulting in a higher energy density for the battery cell. The aforementioned energy density refers to the amount of energy stored in a given space or mass of material.

[0007] In some embodiments, the pressure relief component includes: a pressure relief portion and a connecting portion, the connecting portion being disposed around the outer periphery of the pressure relief portion, the pressure relief portion being connected to a first wall through the connecting portion, at least a portion of the connecting portion protruding from the pressure relief portion in a first direction toward the direction away from the electrode assembly; a protective member being located on the side of the pressure relief portion away from the electrode assembly and connected to the connecting portion, the protective member being spaced apart from the pressure relief portion in the first direction.

[0008] The first wall adopts the structure provided in this embodiment, which is simple and easy to prepare.

[0009] In some embodiments, the end of the connecting portion away from the electrode assembly is provided with a first receiving groove, and at least a portion of the protective member is disposed in the first receiving groove and connected to the inner wall of the first receiving groove.

[0010] By employing the solution provided in this embodiment, the thickness of the combined structure formed by the first wall and the protective member after the protective member is connected to the first protrusion is less than the sum of their thicknesses. This results in a smaller space occupied by the combined structure of the first wall and the protective member, allowing more space for electrode components to be arranged in the battery cell, thus facilitating the improvement of the energy density of the battery cell.

[0011] In some embodiments, in the first direction, the size of the first receiving groove is greater than or equal to the size of the protective member.

[0012] This allows the combined structure of the first wall and the protective component to have a thickness equal to the thickness of the first wall. Compared to schemes where the combined structure's thickness is greater than the thickness of the first wall but less than the sum of the thicknesses of the first wall and the protective component, the solution provided in this embodiment occupies less space, allowing the battery cell to have more space to arrange electrode components, thus facilitating an increase in the energy density of the battery cell.

[0013] In some embodiments, the connecting portion has a first groove on the side facing the electrode assembly; the first groove surrounds the pressure relief portion and communicates with the inner cavity.

[0014] The first groove expands the internal space enclosed by the outer shell, transforming it from a cavity consisting only of the inner cavity into a cavity encompassing both the inner cavity and the first groove. This reduces the weight of the assembly formed by the first wall and the protective component, and provides more space for the electrode assembly, thus contributing to increased energy density of the battery cell. Furthermore, it allows for a thinner pressure relief section, resulting in greater deformation under higher internal pressure. This ensures that the deformation trends of the pressure relief section and the first wall are similar even when the pressure is not high enough to require pressure relief, reducing the risk of cracking at the connection between the connection section and the first wall, thereby improving the reliability of the battery cell structure.

[0015] In some embodiments, the bottom of the first groove is on the same plane as at least a portion of the surface of the pressure relief portion facing the electrode assembly.

[0016] This facilitates processing and allows most of the area of ​​the combined structure of the pressure relief section and the connection section facing the electrode assembly to be flat, which facilitates the arrangement and installation of the internal components of the housing.

[0017] In some embodiments, in a first direction, the groove depth of the first groove is greater than the distance between the surface of the pressure relief portion facing the electrode assembly and the surface of the first wall facing the electrode assembly.

[0018] By adopting the solution provided in this embodiment, compared with the bottom of the first groove being flush with the surface of the pressure relief part, the volume of the first groove can be increased, thereby further expanding the size of the internal space enclosed by the outer shell, further reducing the weight of the assembly composed of the first wall and the protective member, and providing more space for the electrode assembly, which helps to improve the energy density of the battery cell.

[0019] In some embodiments, at least a portion of the sidewall of the first groove near the pressure relief portion is inclined, and the cross-sectional area of ​​the cavity enclosed by the sidewall of the first groove decreases from one side near the electrode assembly to the other.

[0020] By adopting the solution provided in this embodiment, compared to the first groove being arranged with its sidewall near the pressure relief part parallel to the first direction, the volume of the first groove can be increased, thereby further expanding the size of the internal space enclosed by the outer shell, further reducing the weight of the assembly formed by the first wall and the protective member, and providing more space for the electrode assembly, which helps to improve the energy density of the battery cell.

[0021] In some embodiments, at least a portion of the sidewall of the first receiving groove is parallel to at least a portion of the sidewall of the first recess near the pressure relief portion.

[0022] This allows at least a portion of the sidewall of the first receiving groove and the sidewall of the first recess near the pressure relief part to form a thin-wall structure. When the pressure relief part is impacted by gas, the thin-wall structure can also deform, thereby reducing the stress at the connection between the connecting part and the first wall, reducing the risk of cracking at the connection between the connecting part and the first wall, and improving the reliability of the battery cell.

[0023] In some embodiments, the first wall is provided with a pressure relief hole arranged along a first direction, and the pressure relief component and the protective component are both disposed within the pressure relief hole. This makes the structure of the first wall and the pressure relief component relatively simple, facilitating their individual fabrication and assembly.

[0024] In some embodiments, the pressure relief component further includes a limiting portion connected to the pressure relief portion and / or the connecting portion, the limiting portion at least partially overlapping the first wall along the thickness direction of the first wall. The limiting portion stabilizes the relative position of the pressure relief component and the first wall, thereby facilitating the connection operation between the first wall and the pressure relief component.

[0025] In some embodiments, the limiting portion is located on the side of the connecting portion facing the electrode assembly and is spaced apart from the first groove. The limiting portion can be provided on the outer wall of the connecting portion or inserted into the connecting portion. The limiting portion and the first groove are located at the same end of the connecting portion, which facilitates manufacturing and allows for a larger contact area between the end of the pressure relief component facing the electrode assembly and the first wall. In the event of thermal runaway of the battery cell, the pressure relief component is less likely to detach entirely from the first wall, thus contributing to the stability of the battery cell structure.

[0026] In some embodiments, the first wall is provided with a second receiving groove, which communicates with a pressure relief hole. The position of the second receiving groove corresponds to the position of the limiting part, and at least a portion of the limiting part is disposed within the second receiving groove.

[0027] The second receiving groove allows for a smaller thickness in the combined structure of the first wall and the pressure relief component.

[0028] In some embodiments, the side of the connector facing the electrode assembly and the side of the first wall facing the electrode assembly are located on the same plane.

[0029] This allows the connecting part to be flush with the side of the first wall facing the electrode assembly, without occupying the cavity of the inner cavity, which helps to improve the energy density of the battery cell.

[0030] In some embodiments, the sidewalls of the connector and the sidewalls of the pressure relief hole are welded.

[0031] This allows for a stable connection between the connecting part and the first wall.

[0032] In some embodiments, the thickness of the combined structure consisting of the pressure relief part, the connecting part, and the protective member is less than the thickness of the first wall. The side of the first wall facing away from the electrode assembly is provided with a second groove. The second groove is arranged around the pressure relief hole and communicates with the pressure relief hole. The second groove is used to accommodate the third protrusion formed after the sidewall of the connecting part and the sidewall of the pressure relief hole are welded together.

[0033] The second groove is used to accommodate all or part of the third protrusion, so that the third protrusion will not protrude from the first wall, or the part protruding from the first wall is small and will not occupy too much space, thereby helping to improve the energy density of the battery cell.

[0034] In some embodiments, the pressure relief portion and the connecting portion are integrally formed.

[0035] The pressure relief section and the connecting section are integrally molded, which has higher strength, better stability and longer service life compared to the separate structure.

[0036] In some embodiments, the housing further includes a second wall, which is arranged at an angle to or opposite to the first wall, and the battery cell further includes an electrode terminal connected to the electrode assembly, the electrode terminal being disposed on the second wall.

[0037] Electrode terminals are generally located on the end cap. The first wall is the bottom wall or side wall of the outer casing, which allows the pressure relief component to be located on the same wall as the electrode terminals. This results in a higher internal pressure in the battery cell. If the pressure relief component is damaged, the electrolyte flowing out through the pressure relief hole will not come into contact with the electrode terminals. This reduces the risk of damage to the electrode terminals and other electronic components connected to the electrode terminals, and can reduce the risk of battery cell fire and explosion to a certain extent.

[0038] Secondly, embodiments of this application provide a battery device, including a battery cell provided by any of the above solutions.

[0039] Thirdly, embodiments of this application provide an electrical device, including a battery cell or a battery device provided by any of the above solutions.

[0040] The effects of the second and third aspects are the same as those of the first aspect, and will not be elaborated here.

[0041] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies 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 these drawings without creative effort.

[0043] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0044] Figure 2 is an exploded structural diagram of a battery device provided in some embodiments of this application;

[0045] Figure 3 is a schematic diagram of the exploded structure of a battery cell provided in some embodiments of this application;

[0046] Figure 4 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0047] Figure 5 is a side view of the battery cell shown in Figure 4.

[0048] Figure 6 is a schematic cross-sectional view of the structure along line AA in Figure 5;

[0049] Figure 7 is an enlarged structural diagram of point A in Figure 6;

[0050] Figure 8 is a schematic diagram of the structure of the pressure relief component in a battery cell provided in some embodiments of this application;

[0051] Figure 9 is a schematic cross-sectional view of the structure along line BB in Figure 8;

[0052] Figure 10 is a partial cross-sectional view of the combined structure of the first wall and the protective member in a battery cell provided in some other embodiments of this application;

[0053] Figure 11 is a side view of a portion of the structure of a battery cell provided in some other embodiments of this application;

[0054] Figure 12 is a schematic diagram of a partial cross-sectional view along line CC in Figure 11.

[0055] The reference numerals in the detailed embodiments are as follows: 1000, vehicle; 100, battery device; 200, controller; 300, motor; 10, housing; 11, cover; 12, tray; 20, battery cell; 20a, outer shell; 20b, first wall; 20d, second groove; 21, end cap; 22, housing; 23, electrode assembly; 24, pressure relief component; 241, pressure relief part; 242, connecting part; 242a, first protrusion; 242b, first receiving groove; 243, limiting part; 25, protective component; 26, first groove; 27, second receiving groove; Z, first direction. Detailed Implementation

[0056] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, "and / or B" can represent: existing alone, existing with B simultaneously, or existing with B alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0061] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0062] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0063] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0064] A pressure relief device is a mechanism used to release internal pressure within a battery cell to prevent overheating, combustion, or explosion. Pressure relief devices have a significant impact on the reliability of battery cells. For example, when a battery cell experiences a short circuit or overcharging, it may lead to thermal runaway, causing a sudden increase in internal pressure. In such cases, the pressure relief device needs to open to release the gas inside the battery cell, thereby preventing an explosion.

[0065] To prevent external impacts from causing the pressure relief component to open, a protective component is usually installed outside the pressure relief component to provide a certain degree of protection. The protective component also has an exhaust channel to ensure that the pressure inside and outside the protective component is balanced under normal circumstances.

[0066] In related technologies, the protective components in a battery cell are generally mounted on the target component (shell or cover) that carries the pressure relief component, and they protrude from the target component. This means that the battery cell needs to sacrifice height space to accommodate the protective component.

[0067] To address the aforementioned issues, this application provides a battery cell. This battery cell alters the installation method of the protective component, moving it from being stacked on the first wall to being positioned at the location of the pressure relief component. Furthermore, on the same projection plane perpendicular to the first direction, the orthographic projection of the protective component completely falls within the orthographic projection range of the pressure relief component. This allows the thickness of the assembly of the protective component, pressure relief component, and first wall to be less than the sum of the thicknesses of the protective component and the first wall. Therefore, by using the battery cell provided in this application, the thickness of the assembly of the protective component, pressure relief component, and first wall can be reduced. This allows for a smaller outer casing and a larger inner cavity within a limited space, enabling the placement of larger electrode assemblies within the cavity, improving space utilization, and resulting in a higher energy density for the battery cell.

[0068] The battery cells disclosed in this application can be used in battery devices and electrical devices that use the battery cells as a power source, or in various energy storage devices, energy storage systems, and charging networks that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, 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.

[0069] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0070] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 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 apparatus 100 is provided inside the vehicle 1000, and the battery apparatus 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery apparatus 100 can be used to power the vehicle 1000. For example, the battery apparatus 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery apparatus 100 to supply power to the motor 300, for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0071] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0072] Please refer to Figure 2, which is an exploded structural diagram of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10.

[0073] The housing 10 provides a storage space for the battery cells 20, and can adopt various structures. In some embodiments, the housing 10 may include a cover 11 and a tray 12. The cover 11 covers the tray, and together with the tray 12, defines a storage space for accommodating the battery cells 20. The tray 12 may be a hollow structure with one open end, and the cover 11 may be a plate-like structure, covering the open side of the tray 12 so that the cover 11 and the tray 12 together define the storage space; the cover 11 and the tray 12 may also be hollow structures with side openings, with the open side of the cover 11 covering the open side of the tray 12. Of course, the housing 10 formed by the cover 11 and the tray 12 can be of various shapes, such as a circular through-hole, a cuboid, etc. The tray 12 is an important structural support component in the battery system, used to store and protect the battery cells, and also has a significant impact on the collision safety of the vehicle and the overall torsional and bending stiffness of the vehicle body.

[0074] Multiple battery cells 20 can be provided, and these cells can be connected in series, parallel, or mixed connection via a busbar. Mixed connection refers to a configuration where multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or mixed connection, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or mixed connection to form a battery module, and then multiple battery modules connected in series, parallel, or mixed connection to form a whole, housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar for electrical connection between the multiple battery cells 20. As an example, multiple battery cells 20 can form a battery module, which is an independent module formed by arranging and fixing multiple battery cells 20. As an example, a battery module can be formed by binding multiple battery cells 20 together with cable ties.

[0075] Each battery cell 20 can be a secondary battery or a primary battery. A secondary battery refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell 20 can be a 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., and this application embodiment is not limited to this. The battery cell can have a circular through-body, a flat body, a cuboid, or other shapes.

[0076] Please refer to Figure 3, which is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. A battery cell 20 refers to the smallest unit that makes up a battery. As shown in Figure 3, the battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0077] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure or impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals 251 can be provided on end cap 21. Electrode terminals 251 can be used for electrical connection with electrode assembly 23 to output or input electrical energy to battery cell 20.

[0078] The end cap 21 is also provided with a pressure relief component for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment does not impose any special limitations on this. In some embodiments, an insulating component can also be provided on the inner side of the end cap 21. The insulating component can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating component can be plastic, rubber, etc.

[0079] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, circular through-hole, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0080] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 23, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0081] Please refer to Figures 4 to 7. Figure 4 is a structural schematic diagram of a battery cell provided in some embodiments of this application. Figure 5 is a side view of the battery cell shown in Figure 4. Figure 6 is a cross-sectional view along line AA in Figure 5. Figure 7 is an enlarged view of point A in Figure 6. This application provides a battery cell 20. The battery cell 20 includes a housing 20a, a pressure relief component 24, an electrode assembly, and a protective component 25.

[0082] The outer casing 20a has an inner cavity and a first wall 20b. The first wall 20b is located at one end of the outer casing 20a in the first direction Z.

[0083] The pressure relief component 24 is connected to the first wall 20b. The pressure relief component 24 is configured to open at least partially during pressure relief. The electrode assembly is disposed within the inner cavity. The protective member 25 is connected to the side of the pressure relief component 24 away from the inner cavity in the first direction Z. On the same projection plane perpendicular to the first direction Z, the orthographic projection of the protective member 25 falls entirely within the orthographic projection range of the pressure relief component 24.

[0084] The outer casing 20a includes the aforementioned end cap 21 and housing 22. The inner cavity is the cavity enclosed by the end cap 21 and housing 22.

[0085] The first wall 20b can be the end cap 21, or any side wall or bottom wall of the housing 22, depending on the application requirements.

[0086] The pressure relief component 24 is the part of the battery cell 20 that is prone to rupture to release gas when the gas pressure inside the cell is high (such as in the case of thermal runaway). The pressure relief component 24 generally includes an explosion-proof valve, but may also include a vent membrane, or other components that can achieve pressure relief.

[0087] The pressure relief component 24 is separately connected to the first wall 20b.

[0088] The protective component 25 can be a protective patch, film, or other structure or component. It can be made of materials such as plastic, metal foil, or composite materials, and has a certain strength and toughness. Under normal use conditions, it can prevent external contaminants from entering the battery cell 20, prevent the leakage of chemical substances inside the battery cell 20, and prevent the pressure relief component 24 from being damaged by external impacts.

[0089] The protective component 25 can be connected to the pressure relief component 24 or the first wall 20b by bonding, welding or other means, depending on the application requirements.

[0090] In related technologies, the protective element 25 is stacked with the first wall 20b. The edge of the protective element 25 overlaps and connects with the first wall 20b. Thus, the thickness of the combined structure formed by the protective element 25 and the first wall 20b is the sum of the thickness of the protective element 25 and the thickness of the first wall 20b. However, the battery cell 20 provided in this application embodiment changes the installation method of the protective element 25. The protective element 25, which was originally stacked on the first wall 20b, is placed at the location of the pressure relief component 24, so that on the same projection plane perpendicular to the first direction Z, the orthographic projection of the protective element 25 completely falls within the orthographic projection range of the pressure relief component 24. Therefore, the thickness of the combination of the protective element 25, the pressure relief component 24, and the first wall 20b can be less than the sum of the thickness of the protective element 25 and the thickness of the first wall 20b. Therefore, by using the battery cell 20 provided in this embodiment, the thickness of the assembly of the protective component 25, the pressure relief component 24, and the first wall 20b can be reduced. This allows for a smaller outer shell 20a within a limited space, resulting in a larger inner cavity enclosed by the outer shell 20a. This allows for the placement of larger electrode assemblies within the inner cavity, improving space utilization and increasing the energy density of the battery cell 20. The aforementioned energy density refers to the amount of energy stored in a given space or mass of material.

[0091] In the above embodiments, the thickness of at least a portion of the pressure relief component 24 can be less than the thickness of the first wall 20b. A recessed structure is formed in the portion where the pressure relief component 24 is located, and the protective member 25 can be disposed within the recessed structure. This allows the thickness of the protective member 25, the pressure relief component 24, and the first wall 20b to be relatively small, while the inner cavity enclosed by the outer shell 20a is relatively large.

[0092] Figure 8 is a structural schematic diagram of a pressure relief component in a battery cell provided in some embodiments of this application, and Figure 9 is a cross-sectional structural schematic diagram along line BB in Figure 8. As shown in Figures 7 to 9, in some embodiments, the pressure relief component 24 includes a pressure relief portion 241 and a connecting portion 242. The connecting portion 242 is disposed around the outer periphery of the pressure relief portion 241. The pressure relief portion 241 is connected to the first wall 20b through the connecting portion 242. At least a portion of the connecting portion 242 protrudes from the pressure relief portion 241 in a first direction toward the direction away from the electrode assembly. A protective member 25 is located on the side of the pressure relief portion 241 away from the electrode assembly and is connected to the connecting portion 242. The protective member 25 is spaced apart from the pressure relief portion 241 in the first direction Z.

[0093] The pressure relief section 241 is the part of the pressure relief component 24 that is prone to rupture to release gas when the gas pressure in the inner cavity of the battery cell 20 is high (such as in the case of thermal runaway).

[0094] The connecting part 242 is the part of the pressure relief component 24 used to connect the pressure relief part 241 and the first wall 20b.

[0095] For ease of understanding, Figure 7 shows a dividing line L1 between the pressure relief section 241 and the connecting section 242. The portion to the left of L1 in Figure 7 is the connecting section 242, and the portion to the right of L1 is the pressure relief section 241. It should be understood that the dashed line L1 is an auxiliary line to facilitate the distinction between the pressure relief section 241 and the connecting section 242, and is not a structural line of the first wall 20b.

[0096] In the first direction Z, the size of the connecting portion 242 is greater than the thickness of the pressure relief portion 241. The first protrusion 242a is the portion of the connecting portion 242 located on the side of the pressure relief portion 241 away from the electrode assembly.

[0097] For ease of understanding, Figure 9 shows a dividing line L2 between the main body of the connecting portion 242 and the first protrusion 242a. The portion below L2 in Figure 9 is the first protrusion 242a, and the portion above L2 is the main body of the connecting portion 242. It should be understood that the dashed line L2 is an auxiliary line to facilitate the distinction between the main body of the connecting portion 242 and the first protrusion 242a, and is not a structural line of the connecting portion 242.

[0098] The protective element 25 can be bonded, welded or otherwise connected to the first protrusion 242a.

[0099] The first wall 20b adopts the structure provided in this embodiment, which is simple and easy to prepare.

[0100] As shown in Figure 9, in some embodiments, the end of the connecting portion 242 facing away from the electrode assembly is provided with a first receiving groove 242b. At least a portion of the protective member 25 is disposed in the first receiving groove 242b and connected to the inner wall of the first receiving groove 242b.

[0101] The first receiving groove 242b is a groove structure for receiving at least a portion of the protective member 25. The shape of the first receiving groove 242b may or may not be adapted to the shape of the protective member 25.

[0102] By employing the solution provided in this embodiment, after the protective member 25 is connected to the first protrusion 242a, the thickness of the combined structure formed by the first wall 20b and the protective member 25 is less than the sum of their thicknesses. This results in a smaller space occupied by the combined structure formed by the first wall 20b and the protective member 25, allowing the battery cell 20 to have more space to arrange electrode components, thus facilitating the improvement of the energy density of the battery cell 20.

[0103] As shown in Figure 7, in some embodiments, in the first direction Z, the size of the first receiving groove 242b is greater than or equal to the size of the protective member 25.

[0104] This allows the thickness d1 of the combined structure formed by the first wall 20b and the protective member 25 to be equal to the thickness of the first wall 20b. Compared to schemes where the thickness of the combined structure is greater than the thickness of the first wall 20b but less than the sum of the thicknesses of the first wall 20b and the protective member 25, the scheme provided in this embodiment allows the combined structure formed by the first wall 20b and the protective member 25 to occupy less space, giving the battery cell 20 more space to arrange electrode components and facilitating an increase in the energy density of the battery cell 20.

[0105] As shown in Figures 7 to 9, the welding surface between the connecting part 242 and the first wall 20b is m1, the height of m1 is h1, and the assembly height of the protective component 25 is h2. h2 is less than h1 and is within the height range of h1. In this way, the welding area of ​​the connecting part and the assembly area of ​​the protective component share the same height space. The assembly area of ​​the protective component does not occupy the space other than the pressure relief component formed by the combination of the connecting part and the pressure relief part. The first wall assembled with the pressure relief component can be made thin as a whole, which allows the battery cell 20 to have more space to arrange the electrode assembly, which is conducive to improving the energy density of the battery cell 20.

[0106] As shown in Figure 9, in some embodiments, the connecting portion 242 has a first groove 26 on the side facing the electrode assembly. The first groove 26 surrounds the pressure relief portion 241 and communicates with the inner cavity.

[0107] In this embodiment, the cross-sectional area of ​​the first groove 26 is larger than the cross-sectional area of ​​the pressure relief part 241. The aforementioned cross-section is the cross-section obtained by cutting the first groove 26 and the pressure relief part 241 with a section perpendicular to the first direction.

[0108] The first groove 26 expands the internal space enclosed by the outer shell 20a, transforming it from containing only the inner cavity into a cavity encompassing both the inner cavity and the space enclosed by the first groove 26. This reduces the weight of the assembly formed by the first wall 20b and the protective member 25, and provides more space for the electrode assembly, thus helping to improve the energy density of the battery cell 20. On the other hand, it allows for a thinner pressure relief section 241, resulting in greater deformation when the internal air pressure of the battery cell 20 is high. This ensures that when the air pressure does not reach the point where pressure relief section 241 is required, the deformation trends of the pressure relief section 241 and the first wall 20b are similar, which can reduce the risk of cracking at the connection between the connecting section 242 and the first wall 20b to a certain extent, thereby improving the reliability of the battery cell 20 structure.

[0109] In some embodiments, the bottom of the first groove 26 is at least on the same plane as at least a portion of the surface of the pressure relief portion 241 facing the electrode assembly.

[0110] The bottom of the first groove 26 is generally flat. The surface of the pressure relief part 241 facing the electrode assembly can be flat, partially flat, and partially curved or irregular, or it can be a concave-convex surface or an irregular flat surface. The statement that at least a portion of the bottom of the first groove 26 and the surface of the pressure relief part 241 facing the electrode assembly are located on the same plane means that when the surface of the pressure relief part 241 facing the electrode assembly is flat, this plane lies within the plane containing the bottom of the first groove 26; when at least a portion of the surface of the pressure relief part 241 facing the electrode assembly is flat, at least a portion of the flat surface of the pressure relief part 241 facing the electrode assembly lies within the plane containing the bottom of the first groove 26; and when the surface of the pressure relief part 241 facing the electrode assembly is a concave-convex surface or an irregular flat surface, at least a portion of the surface of the pressure relief part 241 facing the electrode assembly lies within the plane containing the bottom of the first groove 26.

[0111] This facilitates processing and allows most of the surface of the combined structure of the pressure relief part 241 and the connecting part 242 facing the electrode assembly to be flat, which facilitates the arrangement and installation of the internal components of the housing 20a.

[0112] Figure 10 is a partial cross-sectional view of the assembly structure of the combination structure of the first wall and the protective member in a battery cell provided in some other embodiments of this application. As shown in Figure 10, in some other embodiments, in the first direction Z, the groove depth d3 of the first groove 26 is greater than the distance d4 between the surface of the pressure relief part 241 facing the electrode assembly and the surface of the first wall 20b facing the electrode assembly.

[0113] By adopting the solution provided in this embodiment, compared with the bottom of the first groove 26 being flush with the surface of the pressure relief part 241, the volume of the first groove 26 can be increased, thereby further expanding the size of the internal space enclosed by the outer shell 20a, further reducing the weight of the assembly formed by the first wall 20b and the protective member 25, and providing more space for the electrode assembly, which helps to improve the energy density of the battery cell 20.

[0114] As shown in Figure 10, in some embodiments, at least a portion of the sidewall m2 of the first groove 26 near the pressure relief portion 241 is inclined. The cross-sectional area of ​​the cavity enclosed by the sidewall of the first groove 26 decreases from the side closest to the electrode assembly to the other side.

[0115] In this embodiment, the longitudinal section of the first groove 26 can be a trapezoid, triangle, or the like, with the opening narrowing from the side closest to the electrode assembly to the other side. The specific shape can be determined according to the usage requirements.

[0116] In this embodiment, the side wall m2 of the first groove 26 near the pressure relief part 241 can be inclined as a whole, or it can be composed of an inclined surface and at least one plane, depending on the usage requirements.

[0117] The cross-sectional area of ​​the cavity formed by the sidewalls of the first groove 26 is set to decrease from the side closest to the electrode assembly to the other side. This can be either a gradual decrease in the cross-sectional area of ​​the cavity formed by the sidewalls of the first groove 26 from the side closest to the electrode assembly to the other side, or a phased decrease.

[0118] For example, when the side wall m2 of the first groove 26 near the pressure relief part 241 is inclined, the cross-section of the cavity formed by the side wall of the first groove 26 is a trapezoidal structure as shown in Figure 10, and the area of ​​the cross-section of the cavity formed by the side wall of the first groove 26 gradually decreases from the side near the electrode assembly to the other side. When the side wall m2 of the first groove 26 near the pressure relief part 241 is composed of an inclined surface and a plane, if the plane is a vertical plane parallel to the first direction Z, the area of ​​the cross-section of the cavity formed by the side wall of the first groove 26 may remain unchanged in the vertical portion corresponding to the side near the electrode assembly.

[0119] Using the solution provided in this embodiment, compared to the first groove 26 being arranged with its side wall m2 near the pressure relief part 241 parallel to the first direction, the volume of the first groove 26 can be increased, thereby further expanding the size of the internal space enclosed by the outer shell 20a, further reducing the weight of the assembly formed by the first wall 20b and the protective member 25, and providing more space for the electrode assembly, which helps to improve the energy density of the battery cell 20.

[0120] As shown in FIG10, in some embodiments, at least a portion of the sidewall m3 of the first receiving groove 242b is parallel to at least a portion of the sidewall m2 of the first groove 26 near the pressure relief portion 241.

[0121] This allows at least a portion of the sidewall of the first receiving groove 242b and the sidewall of the first groove 26 near the pressure relief part 241 to form a thin-walled structure. When the pressure relief part 241 is subjected to gas impact, the aforementioned thin-walled structure can also deform, thereby reducing the stress at the connection between the connecting part 242 and the first wall 20b, reducing the risk of cracking at the connection between the connecting part 242 and the first wall 20b, and improving the reliability of the battery cell 20.

[0122] In some embodiments, the first wall 20b is provided with a pressure relief hole arranged along a first direction, and the pressure relief part, the connecting part and the protective member are all disposed in the pressure relief hole.

[0123] The pressure relief hole is a through hole that penetrates the first wall 20b along the first direction Z.

[0124] This allows for simpler structures for the first wall 20b, the pressure relief section, and the connecting section, facilitating their individual preparation and assembly.

[0125] As shown in FIG10, in some embodiments, the pressure relief component 24 further includes a limiting portion 243 connected to the pressure relief portion 241 and / or the connecting portion 242. The limiting portion 243 at least partially overlaps with the first wall 20b along the thickness direction of the first wall 20b. The limiting portion 243 is used to contact at least one side of the first wall 20b to define the relative position of the connecting portion 242 and the first wall 20b.

[0126] The limiting part 243 can be connected to the connecting part 242, or to the pressure relief part 241, or partly connected to the pressure relief part 241 and partly connected to the connecting part 242, depending on the application requirements. The limiting part 243 can be located inside or outside the pressure relief hole. The limiting part 243 can be provided only on the side of the first wall 20b near the electrode assembly, or only on the side of the first wall 20b away from the electrode assembly, or multiple sets can be provided, with one set on the side of the first wall 20b near the electrode assembly and another set on the side of the first wall 20b away from the electrode assembly, depending on the application requirements.

[0127] The limiting part 243 is used to limit the relative position of the pressure relief component 24 and the first wall 20b by abutting against the wall surface of the first wall 20b.

[0128] The limiting part 243 can stabilize the relative position of the pressure relief part 24 and the first wall 20b, thereby facilitating the connection operation between the first wall 20b and the connecting part 242.

[0129] In some embodiments, the limiting portion 243 is located on the side of the connecting portion 242 facing the electrode assembly and is spaced apart from the first groove 26.

[0130] The limiting part 243 can be provided on the outer wall of the connecting part 242 or inserted into the connecting part 242. The limiting part 243 and the first groove 26 are provided at the same end of the connecting part 242, which is convenient for manufacturing and allows the end of the pressure relief component 24 facing the electrode assembly to have a larger contact area with the first wall 20b. When the battery cell experiences thermal runaway, the pressure relief component 24 is less likely to detach entirely from the first wall 20b, which helps to provide stability to the battery cell structure.

[0131] As shown in Figure 10, in some embodiments, the first wall 20b is provided with a second receiving groove 27. The second receiving groove 27 communicates with the pressure relief hole. The position of the second receiving groove 27 corresponds to the position of the limiting part 243. At least a portion of the limiting part 243 is disposed within the second receiving groove 27.

[0132] The second receiving groove 27 is a groove structure for accommodating at least a portion of the limiting part 243.

[0133] The arrangement of the second receiving groove 27 results in a smaller thickness of the combined structure of the pressure relief component 24 and the first wall 20b.

[0134] In some embodiments, the side of the connecting portion 242 facing the electrode assembly is on the same plane as the side of the first wall 20b facing the electrode assembly.

[0135] This allows the connecting part 242 and the side of the first wall 20b facing the electrode assembly to be flat, without occupying the cavity of the inner cavity, which helps to improve the energy density of the battery cell 20.

[0136] In some embodiments, the sidewall of the connecting portion 242 and the sidewall of the pressure relief hole are welded together.

[0137] This allows for a stable connection between the connecting part 242 and the first wall 20b.

[0138] As shown in Figure 7, in some embodiments, the thickness d1 of the combined structure consisting of the pressure relief part, the connecting part, and the protective member is less than the thickness d2 of the first wall 20b. A second groove 20d is provided on the side of the first wall 20b facing away from the electrode assembly. The second groove 20d surrounds the pressure relief hole and communicates with it. The second groove 20d is used to accommodate a third protrusion formed after welding the sidewall of the connecting part 242 and the sidewall of the pressure relief hole.

[0139] The thickness d1 of the composite structure refers to the dimension of the composite structure in the first direction, and the thickness of the first wall 20b is the dimension of the first wall 20b in the first direction.

[0140] The thickness d1 of the combined structure is less than the thickness of the first wall 20b, and based on the fact that the side of the connecting part 242 facing the electrode assembly and the side of the first wall 20b facing the electrode assembly are on the same plane, the side of the combined structure away from the electrode assembly can be recessed into the pressure relief hole.

[0141] The cross-sectional area of ​​the second groove 20d is greater than the cross-sectional area of ​​the pressure relief hole.

[0142] When welding the sidewall of the connecting part 242 and the sidewall of the pressure relief hole, it is generally done on the outside of the outer shell 20a. In this way, a third protrusion will be formed on the outside of the connection between the connecting part 242 and the pressure relief hole, that is, on the side of the connection between the connecting part 242 and the pressure relief hole away from the electrode assembly. The third protrusion is a protrusion formed by welding.

[0143] The second groove 20d is used to accommodate all or part of the third protrusion, so that the third protrusion will not protrude from the first wall 20b, or the part protruding from the first wall 20b is small and will not occupy too much space, thereby improving the energy density of the battery cell 20.

[0144] In some embodiments, the pressure relief portion 241 and the connecting portion 242 are integrally formed.

[0145] Integrated molding refers to the process of processing materials into a single unit through integrated molding processes (such as casting, injection molding, extrusion molding, etc.), eliminating or reducing the number of separate parts required for assembly.

[0146] The pressure relief part 241 and the connecting part 242 are made by integral molding process. Compared with the separate connection method, the combined structure formed by the two can have higher strength, better stability and longer service life.

[0147] In some embodiments, the housing further includes a second wall, which is arranged at an angle to or opposite to the first wall, and the battery cell further includes an electrode terminal connected to the electrode assembly, the electrode terminal being disposed on the second wall.

[0148] The second wall is a side wall adjacent to the first wall and arranged at an angle, or a side wall opposite to the first wall. As mentioned above, the electrode terminals are generally located on the end cap. Therefore, in this embodiment, the second wall can be the end cap, and the first wall can be the bottom wall or side wall of the outer casing. This allows the pressure relief part to be located on the same wall plate as the electrode terminals, resulting in higher internal gas pressure in the battery cell. If the pressure relief part is damaged, the electrolyte flowing out through the pressure relief hole will not come into contact with the electrode terminals, thereby reducing the risk of damage to the electrode terminals and other electronic components connected to the electrode terminals. This can reduce the risk of the battery cell catching fire or exploding to a certain extent.

[0149] According to some embodiments of this application, this application also provides a battery device including multiple battery cells provided by any of the above solutions.

[0150] The battery device provided in this application embodiment can be a battery pack, energy storage cabinet, etc., which can be determined according to the usage requirements.

[0151] The battery device provided in this application includes multiple battery cells provided by any of the above solutions, which can achieve similar technical effects, and will not be described in detail here.

[0152] According to some embodiments of this application, this application also provides an electrical device, including a battery cell or battery device provided by any of the above solutions. The battery cell or battery device is used to store or provide electrical energy.

[0153] The electrical device can be any of the aforementioned battery-powered devices or systems.

[0154] The electrical device provided in this application embodiment includes the above-mentioned battery cell or battery device, and can achieve the same effect, which will not be described in detail here.

[0155] As shown in Figures 3 to 12, one embodiment of this application provides a battery cell 20. The battery cell 20 includes a housing 20a, an electrode assembly, and a protective component 25.

[0156] The outer casing 20a has an inner cavity and a first wall 20b. The first wall 20b is provided with a pressure relief component 24. The first wall 20b is provided with a pressure relief hole. The pressure relief hole communicates with the inner cavity. The electrode assembly is disposed within the inner cavity. The pressure relief component 24 is disposed within the pressure relief hole and connected to the first wall 20b. The protective component 25 is located within the pressure relief hole and connected to the pressure relief component 24. The thickness d1 of the combined structure formed by the protective component 25 and the pressure relief component 24 is less than or equal to the thickness of the first wall 20b.

[0157] The pressure relief component 24 includes a pressure relief portion 241 and a connecting portion 242. The connecting portion 242 is disposed around the outer periphery of the pressure relief portion 241. The connecting portion 242 connects the pressure relief portion 241 and the first wall 20b. At least a portion of the connecting portion 242 protrudes from the pressure relief portion 241 along a first direction toward a side opposite to the electrode assembly to form a first protrusion 242a. The protective member 25 is connected to the first protrusion 242a and is spaced apart from the pressure relief portion 241 in the first direction Z.

[0158] The first protrusion 242a has a first receiving groove 242b at one end opposite to the electrode assembly. The protective member 25 is disposed in the first receiving groove 242b and is connected to the inner wall of the first receiving groove 242b.

[0159] In the first direction, the size of the first receiving groove 242b is larger than the size of the protective member 25.

[0160] The connecting portion 242 has a first groove 26 on the side facing the electrode assembly. The first groove 26 surrounds the pressure relief portion 241 and communicates with the inner cavity.

[0161] The bottom of the first groove 26 and the side of the pressure relief part 241 facing the electrode assembly are on the same plane.

[0162] In the first direction, the groove depth of the first groove 26 is greater than the distance between the side of the pressure relief portion 241 facing the electrode assembly and the side of the first wall 20b facing the electrode assembly.

[0163] The first groove 26 is inclined near the side wall of the pressure relief part 241, and the cross-sectional area of ​​the cavity formed by the side wall of the first groove 26 decreases from the side closest to the electrode assembly to the other side.

[0164] The sidewall of the first receiving groove 242b is parallel to the sidewall of the first groove 26 near the pressure relief part 241.

[0165] The pressure relief component 24 further includes a limiting portion 243 connected to the pressure relief portion 241 and / or the connecting portion 242. The limiting portion 243 is used to contact at least one side of the first wall 20b to define the relative position of the connecting portion 242 and the first wall 20b. At least one side of the first wall 20b that contacts the limiting portion 243 is provided with a second receiving groove 27. The second receiving groove 27 communicates with the pressure relief hole. At least a portion of the limiting portion 243 is disposed within the second receiving groove 27. The side of the connecting portion 242 facing the electrode assembly is on the same plane as the side of the first wall 20b facing the electrode assembly.

[0166] The sidewall of the connecting part 242 and the sidewall of the pressure relief hole are welded.

[0167] The thickness d1 of the combined structure is less than the thickness of the first wall 20b. A second groove 20d is provided on the side of the first wall 20b facing away from the electrode assembly. The second groove 20d surrounds and communicates with the pressure relief hole. The second groove 20d is used to accommodate a third protrusion formed after welding the sidewall of the connecting part 242 and the sidewall of the pressure relief hole.

[0168] The pressure relief part 241 and the connecting part 242 are integrally formed.

[0169] Using the solution provided in this embodiment, the welding surface between the connecting part 242 and the first wall 20b is m1, the height of m1 is h1, the assembly height of the protective component 25 is h2, h2 is less than h1, and h2 is within the height range of h1. In this way, the welding area of ​​the pressure relief component formed by the combination of the connecting part 242 and the pressure relief part 241 shares the same height space with the assembly area of ​​the protective component. The assembly area of ​​the protective component does not occupy the space other than the pressure relief component. The shell assembled with the pressure relief component can be made thin as a whole, which improves the space volume utilization rate of the battery cell and improves the energy density.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. 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 casing has an inner cavity and a first wall, the first wall being located at one end of the outer casing in a first direction. The pressure relief component is connected to the first wall; Electrode assembly, disposed within the inner cavity; as well as A protective element is connected to the side of the pressure relief component away from the inner cavity in the first direction. On the same projection plane perpendicular to the first direction, the orthographic projection of the protective element falls completely within the orthographic projection range of the pressure relief component.

2. The battery cell as described in claim 1, characterized in that, The pressure relief component includes: Pressure relief section; and A connecting portion is provided around the outer periphery of the pressure relief portion, the pressure relief portion is connected to the first wall through the connecting portion, and at least a portion of the connecting portion protrudes from the pressure relief portion in the first direction toward a direction away from the electrode assembly; The protective component is located on the side of the pressure relief section away from the electrode assembly and is connected to the connecting section. The protective component is spaced apart from the pressure relief section in the first direction.

3. The battery cell as described in claim 2, characterized in that, The end of the connecting portion away from the electrode assembly is provided with a first receiving groove, and at least a portion of the protective member is disposed in the first receiving groove and connected to the inner wall of the first receiving groove.

4. The battery cell as described in claim 3, characterized in that, In the first direction, the size of the first receiving groove is greater than or equal to the size of the protective member.

5. The battery cell as described in claim 3 or 4, characterized in that, The connecting portion has a first groove on the side facing the electrode assembly; the first groove surrounds the pressure relief portion and communicates with the inner cavity.

6. The battery cell as described in claim 5, characterized in that, The bottom of the first groove is on the same plane as at least a portion of the surface of the pressure relief portion facing the electrode assembly.

7. The battery cell as described in claim 5, characterized in that, In the first direction, the groove depth of the first groove is greater than the distance between the surface of the pressure relief portion facing the electrode assembly and the surface of the first wall facing the electrode assembly.

8. The battery cell as described in claim 7, characterized in that, The first groove is inclined at least partially near the sidewall of the pressure relief part, and the cross-sectional area of ​​the cavity formed by the sidewall of the first groove decreases from the side closest to the electrode assembly to the other side.

9. The battery cell as described in claim 8, characterized in that, At least a portion of the sidewall of the first receiving groove is parallel to at least a portion of the sidewall of the first groove near the pressure relief portion.

10. The battery cell according to any one of claims 1-9, characterized in that, The first wall is provided with a pressure relief hole arranged along the first direction, and the pressure relief component and the protective component are both disposed in the pressure relief hole.

11. The battery cell as described in claim 5, characterized in that, The pressure relief component further includes a limiting portion connected to the pressure relief portion and / or the connecting portion, the limiting portion at least partially overlapping the first wall along the thickness direction of the first wall.

12. The battery cell as described in claim 11, characterized in that, The limiting portion is located on the side of the connecting portion facing the electrode assembly and is spaced apart from the first groove.

13. The battery cell as described in claim 11 or 12, characterized in that, The first wall is provided with a second receiving groove, which is connected to the pressure relief hole; the position of the second receiving groove corresponds to the position of the limiting part, and at least a portion of the limiting part is provided in the second receiving groove.

14. The battery cell according to any one of claims 10-13, characterized in that, The side of the connecting portion facing the electrode assembly is on the same plane as the side of the first wall facing the electrode assembly.

15. The battery cell as described in claim 14, characterized in that, The sidewall of the connecting part and the sidewall of the pressure relief hole are welded together.

16. The battery cell as described in claim 15, characterized in that, The thickness of the combined structure formed by the pressure relief part, the connecting part and the protective member is less than the thickness of the first wall. The side of the first wall facing away from the electrode assembly is provided with a second groove. The second groove is arranged around the pressure relief hole and communicates with the pressure relief hole. The second groove is used to accommodate the third protrusion formed after the side wall of the connecting part and the side wall of the pressure relief hole are welded together.

17. The battery cell according to any one of claims 2-16, characterized in that, The pressure relief part and the connecting part are integrally formed.

18. The battery cell according to any one of claims 1-17, characterized in that, The outer casing also includes a second wall, which is arranged at an angle to or opposite to the first wall. The battery cell also includes an electrode terminal connected to the electrode assembly, and the electrode terminal is disposed on the second wall.

19. A battery device, characterized in that, It includes multiple battery cells according to any one of claims 1-18.

20. An electrical device, characterized in that, Includes a battery cell according to any one of claims 1-18 or a battery device according to claim 19.

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