Battery cell, battery device, and electric device

Abstract

The application discloses a battery monomer, a battery device and an electric equipment. The battery monomer comprises a shell, the shell has a first wall, a base material of the first wall is iron or titanium; a pressure relief mechanism is arranged on the first wall; a protective sheet is arranged on a side of the pressure relief mechanism away from an interior of the battery monomer and covers the pressure relief mechanism, the protective sheet comprises a fixing area arranged around an edge of the protective sheet, the fixing area is fixed with the first wall, and the fixing area is in sealing connection with the first wall, and an area of the protective sheet except the fixing area is provided with a through hole. The battery monomer, the battery device and the electric equipment can improve the processing efficiency of the battery monomer, and can also improve the reliability of the battery monomer.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are crucial for the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. For electric vehicles, battery technology is a critical factor in their development. In the development of battery technology, in addition to improving the performance of battery devices, how to improve the processing efficiency of battery devices while ensuring their safe use is also an issue that cannot be ignored. Utility Model Content

[0003] This application provides a battery cell, a battery device, and an electrical appliance, which can improve the processing efficiency of the battery cell and also improve the reliability of the battery cell.

[0004] In a first aspect, a battery cell is provided, comprising: a housing having a first wall, the substrate of the first wall being iron or titanium; a pressure relief mechanism disposed on the first wall; and a protective sheet disposed on the side of the pressure relief mechanism away from the interior of the battery cell and covering the pressure relief mechanism, the protective sheet including a fixing area disposed around the edge of the protective sheet, the fixing area being fixed to the first wall and sealingly connected to the first wall, and the area of ​​the protective sheet other than the fixing area being provided with through holes.

[0005] Therefore, in this embodiment of the battery cell, the base material of the first wall where the pressure relief mechanism is located is iron or titanium. This can improve the structural strength of the battery cell's casing, reduce the risk of casing cracking, and thus improve the structural stability of the battery cell. It can also reduce the thickness of the first wall, thereby increasing the energy density of the battery cell. A protective sheet is disposed on the side of the pressure relief mechanism away from the inside of the battery cell and covers the pressure relief mechanism. This protective sheet can protect the pressure relief mechanism, reduce the risk of damage to the pressure relief mechanism by external forces, and thus improve the service life of the pressure relief mechanism. In addition, the protective sheet includes a fixing area surrounding its edge. This fixing area is fixed to the first wall, and the two are sealed together to improve the connection stability between the protective sheet and the first wall. The area of ​​the protective sheet other than the fixing area has through holes, which can be used for leak detection of the battery cell. For example, helium detection can generally be used, using helium as a tracer gas to detect whether a leak has occurred in the battery cell. Considering that the pressure relief mechanism is structurally weaker than other areas of the battery cell and is more prone to damage, a through-hole is provided on the protective sheet. This allows for the detection of leaking helium gas in the event of a leak in the pressure relief mechanism, a simple and easy-to-implement method. Furthermore, it eliminates the need to machine additional grooves or holes for helium detection on the first wall where the pressure relief mechanism is located, reducing the machining difficulty of the first wall and improving its structural strength.

[0006] In some embodiments, the pressure relief mechanism includes a recess that is recessed into the battery cell relative to the protective sheet, and the through hole corresponds to the recess. By providing the recess, a certain space is created between the area where the through hole of the protective sheet is located and the recess of the pressure relief mechanism. In the event of a leak in the pressure relief mechanism, this space provides a flow space for the leaked helium, allowing the helium to leak through the through hole and be detected.

[0007] In some embodiments, the first wall is provided with a pressure relief hole, the pressure relief mechanism covers the pressure relief hole, and at least a portion of the recess is accommodated within the pressure relief hole. Separating the pressure relief mechanism from the first wall facilitates the manufacturing of the pressure relief mechanism; the recess, which is recessed into the interior of the battery cell, is at least partially accommodated within the pressure relief hole, which reduces the space occupied by the recess within the battery cell and increases the energy density of the battery cell.

[0008] In some embodiments, the pressure relief mechanism further includes a connecting portion located radially outward of the recess and connecting to the area surrounding the pressure relief hole of the first wall. The connecting portion is arranged parallel to the first wall, and the recess is recessed towards the interior of the battery cell relative to the connecting portion. The parallel arrangement of the connecting portion relative to the first wall facilitates a fixed connection between the connecting portion and the first wall, thereby improving structural stability.

[0009] In some embodiments, the pressure relief mechanism further includes a body portion located within the area surrounded by the recess, the body portion protruding towards the interior of the battery cell relative to the recess. During the use of the battery cell, the electrode assembly repeatedly expands and contracts, causing the recess of the pressure relief mechanism to be repeatedly stretched and contracted, which can easily lead to fatigue. The protruding body portion relative to the recess acts as a buffer, bearing some of the stress, reducing the deformation of the recess, and thus reducing its fatigue. Furthermore, along the thickness direction of the pressure relief mechanism, the internal pressure of the battery cell repeatedly increases and decreases. The central area of ​​a flat pressure relief mechanism will repeatedly bulge and recede towards the interior and exterior of the battery cell, causing the weakest area of ​​the flat pressure relief mechanism to be repeatedly bent, which can easily lead to fatigue. However, in the embodiment of this application, where the body portion protrudes relative to the recess, the shape of the body portion can remain relatively stable, reducing the bending angle of the recess, thereby reducing the fatigue of the recess, increasing the service life of the pressure relief mechanism, and ultimately increasing the service life of the battery cell.

[0010] In some embodiments, the first wall is provided with a first groove opening towards the outside of the battery cell, and the bottom wall of the first groove is provided with the pressure relief hole. The connecting portion is provided in the area surrounding the pressure relief hole on the bottom wall of the first groove. By providing the first groove, at least a portion of the pressure relief mechanism is accommodated within the first groove. This reduces the portion of the pressure relief mechanism protruding from the outermost surface of the first wall along the thickness direction of the first wall. Especially when the body portion protrudes towards the outside of the battery cell, providing the first groove reduces the portion of the body portion protruding from the outer surface of the first wall, thus protecting the pressure relief mechanism and reducing the space occupied by the battery cell, thereby increasing the energy density of the battery device.

[0011] In some embodiments, the first wall includes a main structure and a first protrusion structure, the first protrusion structure being located on the side of the bottom wall of the first groove facing the interior of the battery cell, the first protrusion structure protruding relative to the main structure facing the interior of the battery cell to facilitate the processing of the first groove.

[0012] In some embodiments, the surface of the recess facing the interior of the battery cell is further away from the interior of the battery cell than the surface of the first protrusion facing the interior of the battery cell. This first protrusion protects the surface of the recess facing the interior of the battery cell, reducing the impact of the internal components of the battery cell on the pressure relief mechanism.

[0013] In some embodiments, the first wall is provided with a second groove with an opening facing the outside of the battery cell, and the bottom wall of the second groove is provided with the first groove. The fixing area is provided in the area surrounding the first groove on the bottom wall of the second groove. By providing the second groove, at least a portion of the protective sheet can be accommodated within the second groove, reducing the portion of the protective sheet protruding from the outermost surface of the first wall, thereby reducing the space occupied by the battery cell and thus increasing the energy density of the battery device.

[0014] In some embodiments, the first wall includes a main structure and a second protrusion structure. The second protrusion structure is located on the side of the bottom wall of the second groove facing the interior of the battery cell, and the second protrusion structure corresponds to the portion of the bottom wall of the second groove that is not provided with the first groove. The second protrusion structure protrudes relative to the main structure towards the interior of the battery cell to facilitate the processing of the second groove.

[0015] In some embodiments, along the thickness direction of the protective sheet, the depth of the area where the second groove is located in the fixing area is greater than or equal to the thickness of the fixing area, so that the outer surface of the protective sheet facing the battery cell does not exceed the outer surface of the first wall facing the battery cell. This ensures that the pressure relief mechanism and the area where the protective sheet is located do not protrude from the first wall, thus protecting the pressure relief mechanism and the protective sheet, reducing wear, and making the first wall of the battery cell relatively flat, facilitating fixation within the battery device, and improving the structural stability of the battery device.

[0016] In some embodiments, along the thickness direction of the protective sheet, the depth of the region where the second groove is located in the fixing area ranges from [0.1mm, 0.5mm]. Setting the depth of the second groove to be greater than or equal to 0.1mm facilitates the accommodation of the protective sheet; simultaneously limiting the depth of the second groove to less than or equal to 0.5mm, when the thickness of the first wall is limited, reduces the processing difficulty of the second groove and improves the stability of the first wall.

[0017] In some embodiments, the thickness of the fixing region along the thickness direction of the protective sheet ranges from [0.05mm, 0.5mm]. Having a fixing region thickness greater than or equal to 0.05mm improves the structural strength of the protective sheet, facilitating better protection of the pressure relief mechanism and improving the fixation between the fixing region and the second groove, thus enhancing structural stability. Simultaneously, limiting the fixing region thickness to less than or equal to 0.5mm reduces the space occupied by the protective sheet, improving the space utilization of the battery cell and consequently increasing the energy density of the battery cell.

[0018] In some embodiments, the fixing area and the bottom wall of the second groove are fixed together by an adhesive, and the adhesive bonding width along the radial direction of the protective sheet ranges from [0.5mm, 6mm]. Setting the bonding width to be greater than or equal to 0.5mm can improve the bonding stability between the fixing area and the bottom wall of the second groove; setting the bonding width to be less than or equal to 6mm can limit the size of the protective sheet and the second groove, thereby improving the structural strength of the first wall.

[0019] In some embodiments, the distance between the sidewall of the second groove and the surface of the protective sheet facing the sidewall of the second groove is greater than or equal to 0.1 mm. Increasing the distance between the sidewall of the second groove and the protective sheet, i.e., reserving an assembly gap between the protective sheet and the first wall, allows the edge of the protective sheet to also be accommodated within the second groove, reducing the risk of the protective sheet protruding from the outer surface of the first wall. This results in both the outer surfaces of the first wall and the outer surfaces of the protective sheet being relatively flat, improving the stability and reliability of the battery cell.

[0020] In some embodiments, the recess is provided with a weak area that is designed to be broken when the pressure inside the battery cell reaches a threshold to release the pressure, thereby reducing the risk of battery cell explosion and the risk of thermal runaway between multiple battery cells.

[0021] In some embodiments, along the thickness direction of the protective sheet, the distance between the orthographic projection of the area of ​​the recess that is furthest from the protective sheet and the center of the through hole ranges from [0 mm to 20 mm]. A smaller distance results in a larger space on the side of the through hole facing the recess, providing a flow channel for helium gas leaking during helium detection.

[0022] In some embodiments, the maximum distance between the recess and the protective sheet along the thickness direction is in the range of [0.05mm, 3mm]. Setting this distance to be greater than or equal to 0.05mm creates a gap between the recess and the protective sheet. During helium testing, if a leak occurs in the pressure relief mechanism, this gap can provide a channel for helium flow, facilitating detection of leaks through the through-hole and reducing the likelihood of the protective sheet obstructing helium detection, thereby improving detection accuracy. Simultaneously, limiting this distance to less than or equal to 3mm reduces the space between the protective sheet and the pressure relief mechanism, improving the space utilization of the battery cell and thus increasing energy density.

[0023] In some embodiments, the substrate of the pressure relief mechanism is the same as the substrate of the first wall to facilitate welding between the two and to facilitate processing.

[0024] In some embodiments, the diameter of the through hole ranges from [0.1mm, 10mm]. Setting the diameter of the through hole to be greater than or equal to 0.1mm facilitates helium detection and improves detection accuracy; at the same time, limiting the diameter of the through hole to be less than or equal to 10mm can increase the protection area of ​​the protective plate for the pressure relief mechanism, thereby better protecting the pressure relief mechanism.

[0025] In some embodiments, the protective plate is provided with two through holes, which are symmetrically distributed radially relative to the protective plate. Considering that the pressure relief mechanism is usually a symmetrical structure, and the weak area is also a symmetrical structure, the two symmetrical through holes are provided to make the through hole distribution relatively uniform.

[0026] In some embodiments, the housing includes: a shell with a hollow structure having an opening, the first wall being the bottom wall of the shell; and a cover plate for closing the opening. On one hand, the pressure relief mechanism does not require the space of the cover plate, while the cover plate of a battery cell typically needs to house components such as electrode terminals. The pressure relief mechanism being located within the shell saves space on the cover plate and facilitates manufacturing. On the other hand, the pressure relief mechanism can be located on a different wall than the electrode terminals, reducing the impact of emissions discharged through the pressure relief mechanism on the electrode terminals. For example, emissions discharged through the pressure relief mechanism may include conductive particles. By not having the pressure relief mechanism on the same wall as the electrode terminals, the impact of these conductive particles on the electrode terminals can be reduced, lowering the risk of short circuits in the battery cells and thus improving the reliability of the battery device.

[0027] In a second aspect, a battery device is provided, comprising: a plurality of battery cells, wherein the battery cells are those described in the first aspect or any embodiment of the first aspect.

[0028] Thirdly, an electrical device is provided, comprising: a battery device including a battery cell as described in the first aspect or any embodiment of the first aspect, the battery device being used to provide electrical energy to the electrical device.

[0029] In some embodiments, the electrical equipment is a vehicle, a ship, or a spacecraft. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a vehicle according to one embodiment of this application;

[0031] Figure 2 This is a partial structural schematic diagram of a battery device according to an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0033] Figure 4 This is an exploded structural diagram of a battery cell according to an embodiment of this application;

[0034] Figure 5 This is a bottom view of a single battery cell according to an embodiment of this application;

[0035] Figure 6 This is a partial cross-sectional schematic diagram of a battery cell according to an embodiment of this application;

[0036] Figure 7 This is another partial cross-sectional schematic diagram of a battery cell according to one embodiment of this application;

[0037] Figure 8 This is another partial cross-sectional schematic diagram of a battery cell according to an embodiment of this application;

[0038] Figure 9 This is another partial cross-sectional schematic diagram of a battery cell according to an embodiment of this application;

[0039] Figure 10 This is a bottom view of a pressure relief mechanism according to an embodiment of this application.

[0040] The accompanying drawings are not drawn to scale. Detailed Implementation

[0041] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0048] 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).

[0049] 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.

[0050] The battery cell 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 the embodiments of this application are not limited to this.

[0051] In some implementations, the battery cell in this application embodiment can be a metal battery. Specifically, the metal battery may include lithium metal secondary batteries, sodium metal batteries, or magnesium metal batteries, etc. This application embodiment does not limit this.

[0052] The development of battery technology must consider multiple design factors simultaneously, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate, as well as structural stability. Regarding the stability of battery devices, considering that the main hazards arise during charging and discharging, pressure relief mechanisms are typically incorporated into the individual battery cells to improve safety. These pressure relief mechanisms are components or parts that release internal pressure or temperature when it reaches a predetermined threshold.

[0053] Pressure relief mechanisms typically include a weak point, which is designed to be broken down promptly when the internal pressure or temperature of the battery cell reaches a predetermined threshold, thus actuating the mechanism and releasing emissions. Because the weak point is structurally weaker than other areas of the pressure relief mechanism and is more prone to damage, battery cells generally require leak detection to improve their reliability.

[0054] Therefore, embodiments of this application provide a battery cell, a battery device, and an electrical appliance, which facilitates leakage detection of the battery cell to improve its reliability. The battery cell in this application embodiment may include a casing, a pressure relief mechanism, and a protective sheet. The pressure relief mechanism is disposed on the first wall of the casing. The substrate of the first wall is iron or titanium, which can improve the structural strength of the battery cell casing, reduce the risk of casing cracking, and thus improve the structural stability of the battery cell. It can also reduce the thickness of the first wall, thereby increasing the energy density of the battery cell. The protective sheet is disposed on the side of the pressure relief mechanism away from the interior of the battery cell and covers the pressure relief mechanism. This protective sheet can protect the pressure relief mechanism, reduce the risk of damage from external forces, and thus improve the service life of the pressure relief mechanism.

[0055] In addition, the protective sheet includes a fixing area surrounding its edge, which is fixed to the first wall and sealed together to improve the connection stability between the protective sheet and the first wall. The area of ​​the protective sheet other than the fixing area has through holes for detecting leaks in individual battery cells. For example, helium detection can be used, employing helium as a tracer gas to detect leaks in individual battery cells. Considering that the pressure relief mechanism is structurally weaker than other areas of the battery cell and more prone to damage, the through holes in the protective sheet allow for the detection of leaking helium in the event of a leak in the pressure relief mechanism. This method is simple and easy to implement. Furthermore, it eliminates the need to machine additional grooves or holes for helium detection on the first wall where the pressure relief mechanism is located, reducing the machining difficulty of the first wall and improving its structural strength.

[0056] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices.

[0057] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0058] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0059] For example, such as Figure 1 The diagram shown is a structural schematic of a vehicle 1 according to one 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 motor 40, a controller 30, and a battery device 10 can be installed inside vehicle 1. The controller 30 controls the battery device 10 to supply power to the motor 40. For example, the battery device 10 can be installed 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, for example, to meet the electrical system requirements of vehicle 1, such as for starting, navigation, and operation. In another embodiment of this application, the battery device 10 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0060] Figure 2 A partial structural schematic diagram of the battery device 10 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 10 of this application embodiment may include a plurality of battery cells 20 to meet different power usage requirements. The shape of the battery cell 20 in this application embodiment can be set according to actual application. For example, the battery cell 20 can be as follows: Figure 2 The cylindrical shape shown, or it could be different. Figure 2 The embodiments shown may be cuboids or other shapes, but are not limited to these.

[0061] The battery apparatus 10 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 20, which are connected in series, parallel, or mixed connections via busbars.

[0062] In some embodiments, the battery cell assembly is typically formed by arranging a plurality of battery cells 20.

[0063] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 20 together. As an example, a battery module can also be formed by bundling multiple battery cells 20 together with cable ties.

[0064] In some embodiments, the battery device may be a battery pack, which includes a housing 11 and one or more individual battery cells housed within the housing.

[0065] 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.

[0066] As an example, the battery cell assembly can also be housed in the housing by directly fixing multiple battery cells 20 to the housing 11.

[0067] It should be understood that, such as Figure 2 As shown, the housing 11 of this embodiment has a hollow internal structure, and multiple battery cells 20 are housed within the housing 11. The housing 11 may include two parts, referred to herein as a first housing part 111 and a second housing part 112, which are fastened together. The shapes of the first housing part 111 and the second housing part 112 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 20 housed inside. At least one of the first housing part 111 and the second housing part 112 has an opening. For example, as... Figure 2 As shown, the first housing portion 111 and the second housing portion 112 can both be hollow cuboids with one open side each. The openings of the first housing portion 111 and the second housing portion 112 are opposite to each other, and the first housing portion 111 and the second housing portion 112 are interlocked to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the first housing portion 111 and the second housing portion 112.

[0068] For example, unlike Figure 2 As shown, either the first housing portion 111 or the second housing portion 112 may have only one hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 112 as a hollow cuboid with one opening and the first housing portion 111 as a plate-shaped example, then the first housing portion 111 covers the opening of the second housing portion 112 to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20.

[0069] In some embodiments, the battery device 10 may further include other components. For example, the battery device 10 may further include a busbar component, which can be used to realize electrical connections between multiple battery cells 20, such as in parallel, series, or mixed connections. Specifically, the busbar component can realize electrical connections between battery cells 20 by connecting to the electrode terminals 25 of the battery cells 20; or, the busbar component can also realize electrical connections between battery cells 20 by connecting to other components of the battery cells 20. The busbar component can be fixed to corresponding components of the battery cells 20 by welding, for example, by welding to the electrode terminals 25, a sealing structure, or a housing, etc., and the embodiments of this application are not limited thereto.

[0070] Figure 3 A schematic diagram of the structure of a battery cell 20 according to an embodiment of this application is shown, for example, Figure 3 The battery cell 20 shown can be as follows: Figure 2 The battery device 10 shown includes any one of the battery cells 20; Figure 4 This application shows an exploded structural diagram of a battery cell according to an embodiment of the present application. For example, the... Figure 4 It can be Figure 3 A schematic diagram of the exploded structure of the battery cell 20 shown; Figure 5 The diagram shows a bottom view of a battery cell 20 according to an embodiment of this application. For example, the... Figure 5 It can be like Figure 3 and Figure 4 The diagram shows a bottom view of the battery cell 20. Figures 3 to 5 As shown, the battery cell 20 in this embodiment may include a housing 21, a pressure relief mechanism 23, and a protective sheet 24.

[0071] Specifically, the outer casing 21 has a first wall 213, the base material of the first wall 213 being iron or titanium; a pressure relief mechanism 23 is disposed on the first wall 213; a protective sheet 24 is disposed on the side of the pressure relief mechanism 23 away from the interior of the battery cell and covers the pressure relief mechanism 23, the protective sheet 24 includes a fixing area 242 disposed around the edge of the protective sheet 24, the fixing area 242 is fixed to the first wall 213 and is sealed to the first wall 213, and the area of ​​the protective sheet 24 other than the fixing area 242 is provided with a through hole 241.

[0072] It should be understood that the shape of the battery cell 20 in this embodiment can be flexibly set according to actual application. Correspondingly, the outer shell 21 of the battery cell 20 can be any polyhedral structure, for example, it can be set as a cuboid or a cylinder. For example, the external shape of the battery cell 20 can be the same as or different from the shape of its internal electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, the outer shell 21 of the battery cell 20 can also be a cylindrical structure, or it can also be a cuboid structure; or, as Figures 3 to 5 As shown, if the electrode assembly 22 is an approximately cuboid structure, the outer shell 21 can also typically be a cuboid structure, but the embodiments of this application are not limited to this.

[0073] In some embodiments, the housing 21 of the battery cell 20 may include a housing 211, wherein the housing 211 is a hollow structure with an opening 2111 so that the electrode assembly 22 is accommodated within the housing 211; the housing of the battery cell 20 may also include a cover plate 212 for covering the opening 2111 of the housing 211 to isolate the external environment.

[0074] In some embodiments, the number of cover plates 212 is related to the number of openings 2111 in the housing 211. For example, as Figures 3 to 5 As shown, if the housing 211 is a hollow structure with an opening 2111 at one end, the cover plate 212 can be set as one; or, differently, the housing 211 can be a hollow structure with openings 2111 at opposite ends, so that the internal electrode assembly 22 can enter the housing from either side, and the corresponding cover plate 212 can be set as two, with the two cover plates 212 respectively covering the openings 2111 at both ends of the housing 211, but the embodiments of this application are not limited to this.

[0075] In this embodiment of the application, the shapes of the housing 211 and the cover plate 212 are mutually compatible, for example, as Figures 3 to 5 As shown, the housing 211 can be an approximate cuboid structure, and the cover plate 212 is an approximate rectangular plate structure adapted to the housing 211. The cover plate 212 can be any wall of the housing 21. For example, the cover plate 212 can be the wall with the largest area among the multiple walls included in the housing 21, or the wall with the smallest area, or it can be other walls; this embodiment is not limited to these. Alternatively, the cover plate 212 can also have other structures. For example, the cover plate 212 can also be a groove structure with an opening to cover the opening 2111 of the housing 211; this embodiment is not limited to these.

[0076] For ease of explanation, this application mainly uses the outer casing 21 as an example. Figures 3 to 5Taking the approximate cuboid shown as an example, the housing 211 is a hollow structure with an opening 2111 at one end. Correspondingly, a cover plate 212 is provided to cover the opening 2111 of the housing 211. For example, the housing 211 and the cover plate 212 can be sealed by welding to form a closed cavity for placing the electrode assembly 22, thereby improving the sealing reliability.

[0077] In addition, for the rectangular battery cell 20, three reference directions are defined in this embodiment for ease of description. The thickness direction of the battery cell 20 is direction Y, the height direction of the battery cell 20 is direction Z, and the length direction of the battery cell 20 is direction X. The thickness direction Y, the height direction Z, and the length direction X of the battery cell 20 are perpendicular to each other, and the dimension of the battery cell 20 in the thickness direction Y is smaller than the dimension in the length direction X.

[0078] In this embodiment, the first wall 213 of the outer casing 21 is provided with a pressure relief mechanism 23. The first wall 213 can be any wall of the outer casing 21. For example, the first wall 213 can be any wall of the housing 211 or any wall of the cover plate 212.

[0079] Furthermore, in this embodiment, the substrate of the first wall 213 is iron or titanium, where "substrate" refers to the material with the highest weight percentage in the material of the first wall 213. This improves the structural strength of the first wall 213 of the battery cell 20, reduces the risk of cracking of the casing 21, thereby increasing the structural stability of the battery cell 20, and also reduces the thickness of the first wall 213, thus increasing the energy density of the battery cell 20.

[0080] The first wall 213 of this application embodiment is provided with a pressure relief mechanism 23, which is used to discharge the internal gas of the battery cell 20.

[0081] As an example, the internal pressure or temperature of the battery cell 20 is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. For instance, when the internal pressure or temperature of the battery cell 20 reaches the predetermined threshold, the pressure relief mechanism 23 is activated or a weak area 2311 in the pressure relief mechanism 23 is damaged, thereby forming an opening or channel for the release of internal pressure or temperature. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 20.

[0082] As an example, the pressure relief mechanism 23 can be integrally formed with the first wall 213; or, the pressure relief mechanism 23 can be separately set and connected to the first wall 213.

[0083] The term "actuation" as used in this application refers to the pressure relief mechanism 23 being activated or undergoing a certain state, thereby releasing the internal pressure and temperature of the battery cell 20. The actions of the pressure relief mechanism 23 may include, but are not limited to: movement of components within the pressure relief mechanism 23 to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the pressure relief mechanism 23, etc. When the pressure relief mechanism 23 is actuated, the high-temperature, high-pressure substances inside the battery cell 20 are discharged outwards from the actuated portion as exhaust materials. This method enables pressure and temperature relief of the battery cell 20 under controllable pressure or temperature conditions, thereby preventing potentially more serious accidents.

[0084] The emissions from the battery cell 20 mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0085] The battery cell 20 in this embodiment of the application also includes a protective sheet 24. The protective sheet 24 is disposed on the side of the pressure relief mechanism 23 away from the interior of the battery cell 20 and covers the pressure relief mechanism 23. The protective sheet 24 can be used to protect the pressure relief mechanism 23, reduce the risk of the pressure relief mechanism 23 being damaged by external forces, and thus improve the service life of the pressure relief mechanism 23.

[0086] The protective sheet 24 in this embodiment includes a fixing area 242 surrounding the edge of the protective sheet 24. The annular fixing area 242 is fixed to the first wall 213 and is sealed to the first wall 213 to improve the connection stability between the protective sheet 24 and the first wall 213. Specifically, the fixing area 242 is annular so that each area of ​​the edge of the protective sheet 24 is sealed to the first wall 213.

[0087] Furthermore, in this embodiment, the protective sheet 24, excluding the fixing area 242, is provided with through holes 241, which can be used for leak detection of the battery cell 20. For example, helium detection can generally be used, employing helium as a tracer gas to detect whether the battery cell 20 is leaking. Considering that the pressure relief mechanism 23 is structurally weaker than other areas of the battery cell 20 and is prone to damage, the through holes 241 in the protective sheet 24 allow for the detection of leaked helium in the event of a leak in the pressure relief mechanism 23. This method is simple and easy to implement. Moreover, considering that the substrate of the first wall 213 is iron or titanium, machining grooves or holes for helium detection on the first wall 213 is difficult and detrimental to the structural stability of the first wall 213, as well as the sealing between the first wall 213 and the protective sheet 24. Therefore, by setting through holes 241 on the protective sheet 24 for helium detection, it is not necessary to process additional grooves or holes for helium detection on the first wall 213 where the pressure relief mechanism 23 is located, which reduces the processing difficulty of the first wall 213 and can also improve the structural strength of the first wall 213.

[0088] It should be understood that, such as Figures 3 to 5 As shown, the battery cell 20 in this embodiment may also include other components. For example, the battery cell 20 may also include an electrode assembly 22, which is housed within the housing 21.

[0089] The electrode assembly 22 in this embodiment can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0090] In some embodiments, the electrode assembly 22 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0091] In some embodiments, the electrode assembly 22 is a stacked structure. As an example, multiple positive and negative electrodes can be provided, with multiple positive and multiple negative electrodes stacked alternately. Alternatively, as an example, multiple positive electrodes can be provided, and negative electrodes can be folded to form multiple stacked folded segments, with a positive electrode sandwiched between adjacent folded segments. Alternatively, as an example, both positive and negative electrodes can be folded to form multiple stacked folded segments.

[0092] As an example, multiple separators can be provided, each positioned between any two adjacent positive or negative electrode plates. As another example, separators can be provided continuously, positioned between any two adjacent positive or negative electrode plates by folding or winding.

[0093] In some embodiments, the electrode assembly 22 may be cylindrical, flat, or polygonal in shape.

[0094] In some embodiments, the electrode assembly 22 may include a tab 222 and an electrode body 221. Specifically, as shown... Figures 3 to 5 As shown, the electrode assembly 22 may include at least two tabs 222, which may include at least one positive tab 2221 and at least one negative tab 2222. The positive tab 2221 may be formed by stacking the portion of the positive electrode sheet that is not coated with the positive active material layer, while the portion of the positive electrode sheet coated with the positive active material layer may be formed into the electrode body portion 221 by winding or stacking. The negative tab 2222 may be formed by stacking the portion of the negative electrode sheet that is not coated with the negative active material layer, while the portion of the negative electrode sheet coated with the negative active material layer may be formed into the electrode body portion 221 by winding or stacking.

[0095] In some embodiments of this application, an insulating film may be provided on the outside of the electrode assembly 22 to improve the insulation between the electrode assembly 22 and the housing 21. For example, an insulating film may be wrapped around the outer surface of the electrode body 221 of the electrode assembly 22 to isolate the electrode body 221 from the housing 21 and improve the insulation reliability of the battery cell 20.

[0096] In this embodiment, the plurality of tabs 222 of the electrode assembly 22 can be located on the same or different end faces of the electrode assembly 22. For example, the electrode assembly 22 may include two tabs 222, which may be located on the same end face, or the two tabs 222 may be disposed on different end faces, for example, the two tabs 222 may be located on end faces disposed opposite each other. This embodiment is not limited thereto. For ease of explanation, as follows Figure 3 and Figure 5 As shown, the embodiment of this application mainly takes the electrode assembly 22 as an example, which includes two tabs 222, and both tabs 222 are disposed on the end face of the electrode assembly 22 facing the cover plate 212.

[0097] In some embodiments, the battery cell 20 may also have electrode terminals 25 on its housing 21. These electrode terminals 25 are used to electrically connect to the electrode assembly 22 within the housing 21 to output electrical energy from the battery cell 20. The battery cell 20 may include at least two electrode terminals 25, each including at least one positive electrode terminal 251 and at least one negative electrode terminal 252. Each electrode terminal 25 is used to electrically connect to a corresponding tab 222. For example, each electrode terminal 25 may be electrically connected to a corresponding tab 222 via a connecting member 26. For instance, the positive tab 2221 of the electrode assembly 22 may be connected to the positive electrode terminal 251 via one connecting member 26, and the negative tab 2222 of the electrode assembly 22 may be connected to the negative electrode terminal 252 via another connecting member 26.

[0098] At least two electrode terminals 25 of the battery cell 20 can be disposed on the same wall or different walls of the battery cell 20. For example, the positions of the electrode terminals 25 can be set according to the positions of the tabs 222 of the electrode assembly 22. For example, as Figures 3 to 5 As shown, the embodiment of this application mainly takes the battery cell 20 as having two electrode terminals 25, and both electrode terminals 25 are disposed on the cover plate 212 of the outer shell 21 of the battery cell 20 as an example.

[0099] Figure 6 A partial cross-sectional schematic diagram of a battery cell 20 according to an embodiment of this application is shown. For example, the... Figure 6 It can be along such Figure 5 The local area of ​​the first wall 213 in the cross-sectional view along the A-A' direction shown; Figure 7 Another partial cross-sectional schematic diagram of the battery cell 20 according to an embodiment of this application is shown, for example, Figure 7 It can be Figure 6 An enlarged view of region C shown. Figure 8 This illustration shows another partial cross-sectional view of a battery cell 20 according to an embodiment of this application. For example, the... Figure 8 The cross-section is perpendicular to the length direction X of the battery cell 20, for example, the Figure 8 It can be along such Figure 5 A schematic diagram of a local area of ​​the first wall 213 in the cross-sectional view along the B-B' direction shown; Figure 9 This paper shows another partial cross-sectional schematic diagram of the battery cell 20 according to an embodiment of the present application, for example, Figure 9 It can be Figure 8 Enlarged view of the first wall 213 in the middle.

[0100] It should be understood that the first wall 213 where the pressure relief mechanism 23 is located in this embodiment can be any wall of the outer casing 21. For example, the first wall 213 can be the bottom wall of the casing 211. On the one hand, the pressure relief mechanism 23 does not need to occupy the space of the cover plate 212, while the cover plate 212 of the battery cell 20 usually needs to be provided with components such as electrode terminals 25. The pressure relief mechanism 23 is located in the casing 211, which can save the space of the cover plate 212 and facilitate processing. On the other hand, the pressure relief mechanism 23 can be on a different wall than the electrode terminals 25, which reduces the impact of the emissions discharged through the pressure relief mechanism 23 on the electrode terminals 25. For example, the emissions discharged through the pressure relief mechanism 23 may include conductive particles. By not having the pressure relief mechanism 23 on the same wall as the electrode terminals 25, the impact of these conductive particles on the electrode terminals 25 can be reduced, thereby reducing the risk of short circuit in the battery cell 20 and improving the reliability of the battery device 10.

[0101] It should be understood that the substrate of the first wall 213 in this application embodiment is iron or titanium, and the specific material of the first wall 213 can be set according to the actual application. For example, if the substrate of the first wall 213 is iron, the material of the first wall 213 includes stainless steel; as another example, if the substrate of the first wall 213 is titanium, the material of the first wall 213 includes titanium alloy, which is convenient to meet the design requirements of strength and easy to implement. The stainless steel material may include at least one of SUS 304, SUS 316L and SUS 305, but the embodiments of this application are not limited to this.

[0102] In some embodiments, the material of the pressure relief mechanism 23 of this application can be set according to the actual application. For example, the base material of the pressure relief mechanism 23 is the same as the base material of the first wall 213, so as to facilitate welding between the two and facilitate processing.

[0103] It should be understood that the "base material" of the pressure relief mechanism 23 refers to the material with the highest weight percentage in the material of the pressure relief mechanism 23. For example, the material of the pressure relief mechanism 23 may include at least one of the following: iron-carbon alloy, stainless steel, cast iron, and alloy steel, etc., to improve the structural strength of the pressure relief mechanism 23. Among them, the stainless steel material may include SUS 304 and / or SUS 316L, but the embodiments of this application are not limited to this.

[0104] It should be understood that the thickness T of the first wall 213 in this embodiment can be set according to actual application. For example, as Figures 6 to 9 As shown, the thickness T of the first wall 213 ranges from [0.075mm, 0.4mm]; for example, the thickness T of the first wall 213 ranges from [0.075mm, 0.25mm]. On the one hand, setting the thickness T of the first wall 213 to be greater than or equal to 0.075mm facilitates processing and improves the structural strength of the casing 211 where the first wall 213 is located, thereby improving the structural stability of the battery cell 20. On the other hand, setting the thickness T of the first wall 213 to be less than or equal to 0.4mm, or further, setting the thickness T of the first wall 213 to be less than or equal to 0.25mm, can reduce the volume of the battery cell 20, effectively reduce the weight of the battery cell 20, and increase the energy density of the battery cell 20.

[0105] In some embodiments, the thickness T of the first wall 213 can be any one of the following values ​​or between any two of the following values: 0.075mm, 0.1mm, 0.125mm, 0.15mm, 0.175mm, 0.2mm, 0.225mm, 0.25mm, 0.275mm, 0.3mm, 0.325mm, 0.35mm, 0.375mm, and 0.4mm.

[0106] It should be understood that the thickness T of the first wall 213 in this embodiment can refer to the average thickness of at least a portion of the first wall 213. For example, the thickness T of the first wall 213 can refer to the average thickness of the areas of the first wall 213 other than the area where the pressure relief mechanism 23 is located, especially when the first wall 213 is relatively flat and has a relatively uniform thickness, that is, when the thickness of all or most of the other areas of the first wall 213 other than the area of ​​the pressure relief mechanism 23 is basically equal or the difference is small, then the average thickness of the other areas of the first wall 213 can be determined as T. Alternatively, the thickness T of the first wall 213 can also refer to the average thickness of a local area of ​​the first wall 213, for example, it can refer to the average thickness of a local area of ​​the first wall 213 near the pressure relief mechanism 23. This embodiment is not limited to this.

[0107] In some embodiments, the thickness of the other walls of the outer casing 21 may be the same as or different from the thickness of the first wall 213, and the embodiments of this application are not limited thereto. For example, the thickness of the shell 211 of the outer casing 21 may be set to satisfy [0.075mm, 0.25mm], and the thickness of the side walls of the shell 211 may be the same as or different from the thickness of the bottom wall.

[0108] The pressure relief mechanism 23 of this application embodiment will now be described with reference to the accompanying drawings.

[0109] It should be understood that the structure of the pressure relief mechanism 23 in this application embodiment can be configured according to actual applications. Figure 10 A bottom view schematic diagram of the pressure relief mechanism 23 of the battery cell 20 according to an embodiment of this application is shown. For example, the... Figure 10 It can be like Figures 3 to 9 The battery cell 20 shown includes a pressure relief mechanism 23, and Figure 10 The surface of the pressure relief mechanism 23 facing the outside of the battery cell 20 is shown.

[0110] In some embodiments, the pressure relief mechanism 23 includes a recess 231 that is recessed into the battery cell 20 relative to the protective sheet 24, and a through hole 241 corresponds to the recess 231. By providing the recess 231, a certain space is created between the area where the through hole 241 of the protective sheet 24 is located and the recess 231 of the pressure relief mechanism 23. In the event of a leak in the pressure relief mechanism 23, this space provides a flow space for the leaked helium gas, allowing the helium gas to leak through the through hole 241 and be detected.

[0111] It should be understood that the structure of the recess 231 in this embodiment can be configured according to actual applications. For example, as Figures 6 to 10 As shown, the recess 231 can be a groove structure or a near-groove structure to facilitate processing.

[0112] In some embodiments, the recess 231 is provided with a weak region 2311, which is designed to be broken when the pressure inside the battery cell 20 reaches a threshold to release pressure. The weak region 2311 included in the pressure relief mechanism 23 of this application embodiment can be implemented in various ways. For example, as... Figures 6 to 10 As shown, the weak area 2311 can be a groove or a notch, so that the thickness of the weak area 2311 is less than the thickness of other areas of the pressure relief mechanism 23, thereby reducing the structural strength of the weak area 2311 and making it easier to be damaged. For example, the weak area 2311 can also be provided with a temperature-sensitive material, so that when the internal temperature of the battery cell 20 exceeds a threshold, the weak area 2311 is easily melted. For ease of explanation, this embodiment mainly uses a groove as an example to illustrate the weak area 2311.

[0113] It should be understood that the specific location of the weak area 2311 in this application embodiment can be set according to actual application. For example, as Figures 6 to 10 As shown, the weak area 2311 can be annular. The weak area 2311 can be continuously and circumferentially arranged at the edge of the pressure relief mechanism 23 so that the weak area 2311 is evenly distributed. When the battery cell 20 experiences thermal runaway, any area of ​​the annular weak area 2311 may be destroyed, so that the pressure relief mechanism 23 can promptly remove the emissions inside the battery cell 20, reduce the risk of thermal diffusion between multiple battery cells 20, and improve the reliability of the battery device 10.

[0114] For example, the location of the weak area 2311 can be determined based on the shape and location of the recess 231 to improve the stability and reliability of the weak area 2311. When the battery cell 20 is in normal use, the weak area 2311 is relatively stable. However, in the event of thermal runaway of the battery cell 20, the weak area 2311 can be destroyed in time to quickly release emissions, reduce the risk of battery cell 20 explosion and thermal diffusion between multiple battery cells 20, and improve the reliability of the battery device 10.

[0115] In this embodiment, the pressure relief mechanism 23 and the first wall 213 can be integrally formed or separately configured.

[0116] In some embodiments, the first wall 213 is provided with a pressure relief hole 2133, the pressure relief mechanism 23 covers the pressure relief hole 2133, and at least a portion of the recess 231 is accommodated within the pressure relief hole 2133. Separating the pressure relief mechanism 23 from the first wall 213 facilitates the processing of the pressure relief mechanism 23; the recess 231, which is recessed into the interior of the battery cell 20, is at least partially accommodated within the pressure relief hole 2133, which reduces the space occupied by the recess 231 within the battery cell 20 and improves the energy density of the battery cell 20.

[0117] In some embodiments, the recess 231 of this application embodiment can be disposed around the inner side of the pressure relief hole 2133, that is, the recess 231 of the pressure relief mechanism 23 is disposed along the inner circumferential direction of the pressure relief hole 2133, so that the pressure relief mechanism 23 has a symmetrical shape and uniform force distribution, which can improve the stability and reliability of the pressure relief mechanism 23. Correspondingly, the weak area 2311 of the recess 231 is annular, for example, it can be disposed around the area near the inner wall of the pressure relief hole 2133.

[0118] In some embodiments, the pressure relief mechanism 23 further includes a connecting portion 232, which is located outside the recess 231 along the radial direction of the pressure relief mechanism 23 and connects to the area surrounding the pressure relief hole 2133 of the first wall 213. For example... Figures 6 to 10 As shown, in this embodiment, the radial direction of the pressure relief mechanism 23 is from the central region of the pressure relief mechanism 23 to the edge region. For example, taking the surface of the pressure relief mechanism 23 facing the outside of the battery cell 20 as an example, the radial direction of the pressure relief mechanism 23 refers to the direction from the center point of the surface to the edge of the surface. Along the radial direction of the pressure relief mechanism 23, the connecting portion 232 is located outside the recess 231, that is, the connecting portion 232 is farther away from the central region of the pressure relief mechanism 23 than the recess 231. For example, the connecting portion 232 can be arranged around the edge of the pressure relief mechanism 23, that is, it can be arranged around the recess 231, and the relative fixation between the pressure relief mechanism 23 and the first wall 213 is achieved through the connecting portion 232.

[0119] It should be understood that the fixing method between the pressure relief mechanism 23 and the first wall 213 in this application embodiment can be set according to actual application. For example, the connecting part 232 of the pressure relief mechanism 23 and the first wall 213 can be fixed by welding, which is convenient for processing and can improve structural stability. Specifically, the connecting part 232 of the pressure relief mechanism 23 and the first wall 213 can be fixedly connected by seam welding or through welding, but this application embodiment is not limited to this.

[0120] In some embodiments, the connecting portion 232 is arranged parallel to the first wall 213, and the recess 231 is recessed toward the interior of the battery cell 20 relative to the connecting portion 232. For example... Figures 6 to 10As shown, the connecting portion 232 is arranged parallel to the first wall 213, facilitating a fixed connection between the connecting portion 232 and the first wall 213 to improve structural stability. For example, in this embodiment, "parallel arrangement" includes at least the portion of the connecting portion 232 facing the first wall 213 that connects to the first wall 213, and the portion of the first wall 213 facing the connecting portion 232 that connects to the connecting portion 232, which are arranged parallel to each other to allow for closer contact between the connecting portion 232 and the portion connected to the first wall 213, thus improving connection stability. For example, the connecting portion 232 can be a plate-like structure, i.e., the connecting portion 232 is relatively flat, rather than an uneven or inclined area, to facilitate a fixed connection with the equally flat first wall 213.

[0121] In some embodiments, the connecting portion 232 of the pressure relief mechanism 23 is disposed around the recess 231, wherein the specific structure of the recess 231 can be configured according to the actual application. For example, the recess 231 can be the part of the pressure relief mechanism 23 other than the connecting portion 232, that is, except for the connecting portion 232, the rest of the pressure relief mechanism 23 is recessed relative to the connecting portion 232 toward the interior of the battery cell 20 to form the recess 231. This shape is simple and easy to implement.

[0122] During the use of the battery cell 20, the electrode assembly 22 repeatedly expands and contracts, and the pressure relief mechanism 23 is repeatedly stretched and contracted, which easily leads to fatigue, especially in the weak area 2311, which has a relatively weak structure and is more prone to fatigue, causing the pressure relief mechanism 23 to fail. However, by setting the recess 231 to be recessed towards the inside of the battery cell 20, it can play a buffering role, bear part of the force, reduce the deformation of the recess 231, and also reduce the fatigue of the weak area 2311. Furthermore, along the thickness direction of the pressure relief mechanism 23, for example, the thickness direction of the pressure relief mechanism 23 can be the height direction Z of the battery cell 20, the pressure inside the battery cell 20 repeatedly increases and decreases. The middle area of ​​the flat pressure relief mechanism will repeatedly bulge and sink towards the inside and outside of the battery cell 20, which will also cause at least a local area of ​​the flat pressure relief mechanism to be repeatedly bent, making it prone to fatigue. However, the recess 231 of this embodiment is recessed towards the inside of the battery cell 20, which can keep the shape of the pressure relief mechanism 23 relatively stable, reduce the bending angle of the local area, thereby reducing the fatigue of the pressure relief mechanism 23, improving the service life of the pressure relief mechanism 23, and thus improving the service life of the battery cell 20.

[0123] For example, the recess 231 of the pressure relief mechanism 23 can also be an annular structure with other formed structures inside.

[0124] In some embodiments, the pressure relief mechanism 23 further includes a body portion 233 located in the region surrounded by the recess 231, the body portion 233 protruding relative to the recess 231 toward the interior away from the battery cell 20. For example... Figures 6 to 10 As shown, in this embodiment, the body portion 233 is located within the inner circle of the annular recess 231, meaning the recess 231 surrounds the body portion 233. The body portion 233 in this embodiment has a raised structure, meaning it is not flat. For example, as... Figures 6 to 10 As shown, the entire area of ​​the body portion 233 is a raised structure that protrudes from the inside of the battery cell 20, that is, a raised structure that protrudes in the direction away from the electrode assembly 22.

[0125] Or, unlike... Figures 6 to 10 As shown, the body portion 233 may also have a portion of a raised structure protruding toward the direction of the electrode assembly 22, and a portion of a raised structure protruding away from the electrode assembly 22. For example, the body portion 233 may be a wavy structure, but the embodiments of this application are not limited thereto.

[0126] Thus, during the use of the battery cell 20, the electrode assembly 22 repeatedly expands and contracts, causing the recess 231 of the pressure relief mechanism 23 to be repeatedly stretched and contracted, which can easily lead to fatigue. The body portion 233, however, protrudes relative to the recess 231, acting as a buffer, bearing some of the force, reducing the deformation of the recess 231, and thus reducing its fatigue. Furthermore, along the thickness direction of the pressure relief mechanism 23, for example, the thickness direction of the pressure relief mechanism 23 could be the height direction Z of the battery cell 20, the internal pressure of the battery cell 20 repeatedly increases and decreases. The central area of ​​the flat pressure relief mechanism will repeatedly bulge and concave towards the inside and outside of the battery cell 20, causing the weak areas of the flat pressure relief mechanism to be repeatedly bent, which can easily lead to fatigue. In the embodiment of this application, where the body portion 233 protrudes relative to the recess 231, the shape of the body portion 233 can be kept relatively stable, reducing the bending angle of the recess 231, thereby reducing the fatigue of the recess 231, increasing the service life of the pressure relief mechanism 23, and consequently increasing the service life of the battery cell 20.

[0127] In addition, if the weak area 2311 included in the recess 231 is provided with a groove, during the process of processing the groove by stamping, the main body 233 is subjected to the squeezing force towards the center of the pressure relief mechanism 23. Different areas of the main body 233 deform in the direction of its bulge, and the direction of the deformation is consistent, thereby making the overall shape of the pressure relief mechanism 23 stable and ensuring the burst consistency of the pressure relief mechanism 23.

[0128] For ease of explanation, such as Figures 6 to 10As shown, this embodiment of the application mainly uses the example of a raised structure protruding from the inside of the battery cell 20, where the entire area of ​​the body portion 233 is a raised structure protruding in a direction away from the electrode assembly 22. Furthermore, along the thickness direction of the protective sheet 24, the portion of the recess 231 furthest from the protective sheet 24 is typically provided with a weak area 2311, for example, such as... Figures 6 to 10 As shown, the recess 231 has an approximate groove structure, and the weak area 2311 is usually located on the bottom wall of the recess 231.

[0129] When the battery cell 20 is operating normally, the internal air pressure or temperature of the battery cell 20 is low. The following explanation uses air pressure as an example. The air pressure inside the battery cell 20 continuously acts on the pressure relief mechanism 23, causing the recess 231 and the body portion 233 to move outward or tend to move outward. The body portion 233 tends to have a smaller perimeter and shrink towards the center.

[0130] Because a portion of the recess 231 slopes inward toward the interior of the battery cell 20, the weak area 2311 is positioned closer to the interior of the battery cell 20 than the connecting portion 232. Furthermore, one end of the sloped portion is constrained by the connecting portion 232. Under air pressure, this end of the sloped portion extending into the battery cell 20 will press against the weak area 2311, thereby suppressing cracking of the weak area 2311, reducing the risk of creep failure of the pressure relief mechanism 23 during normal operation of the battery cell 20, and effectively extending the lifespan of the pressure relief mechanism 23. On the other hand, the outwardly protruding body portion 233 can support the weak area 2311 and also effectively compress it.

[0131] When the internal pressure or temperature of the battery cell 20 continues to rise until it exceeds or equals a predetermined value, the battery cell 20 may be about to experience thermal runaway. The inclined portion between the connecting portion 232 and the weak area 2311 can flip outward from its state of extending towards the inside of the battery cell 20 to a state of extending away from the inside of the battery cell 20. Specifically, when the internal pressure or temperature of the battery cell 20 rises to or exceeds a predetermined value, the recess 231 and the body portion 233 as a whole continue to move outward. Among them, the inclined portion between the connecting portion 232 and the weak area 2311 undergoes significant deformation, flipping outward from its state of extending towards the inside of the battery cell 20 to a state of extending away from the inside of the battery cell 20. More specifically, the portion of the inclined portion adjacent to the weak area 2311 becomes a state of extending away from the inside of the battery cell 20, while the portion adjacent to the connecting portion 232 is constrained by the connecting portion 232 and its movement is relatively small. After the inclined portion between the connecting part 232 and the weak area 2311 is flipped, this portion essentially becomes a state extending away from the inside of the battery cell 20, and this portion changes from a state of compressing the weak area 2311 to a state of stretching the weak area 2311, promoting the cracking of the weak area 2311 and facilitating rapid pressure relief. On the other hand, the main body 233 moves outward of the battery cell 20 under air pressure, also stretching the weak area 2311, promoting the cracking of the weak area 2311 and facilitating rapid pressure relief.

[0132] In some embodiments, the first wall 213 is provided with a first groove 2131 with an opening facing the outside of the battery cell 20, the bottom wall of the first groove 2131 is provided with a pressure relief hole 2133, and the connecting portion 232 is provided in the area surrounding the pressure relief hole 2133 on the bottom wall of the first groove 2131. Figures 6 to 10 As shown, by providing the first groove 2131, at least a portion of the pressure relief mechanism 23 is accommodated within the first groove 2131. This reduces the portion of the pressure relief mechanism 23 protruding from the outermost surface of the first wall 213 along the thickness direction of the first wall 213. Especially when the body portion 233 protrudes outward toward the battery cell 20, providing the first groove 2131 reduces the portion of the body portion 233 protruding from the outer surface of the first wall 213. This protects the pressure relief mechanism 23 and reduces the space occupied by the battery cell 20, thereby increasing the energy density of the battery device 10.

[0133] In some embodiments, the first wall 213 includes a main structure 2134 and a first protrusion structure 2135. The first protrusion structure 2135 is located on the side of the bottom wall of the first groove 2131 facing the interior of the battery cell 20, and the first protrusion structure 2135 protrudes relative to the main structure 2134 towards the interior of the battery cell 20. Figures 6 to 10As shown, the first wall 213 is provided with a first groove 2131, which is usually processed by stamping. Considering that the base material of the first wall 213 is iron or titanium, the first wall 213 has high structural strength and is difficult to thin by stamping to obtain the first groove 2131. Therefore, when the first groove 2131 is obtained by stamping, a first protrusion structure 2135 is usually formed on the side of the bottom wall of the first groove 2131 facing the interior of the battery cell 20 to facilitate the processing of the first groove 2131.

[0134] In some embodiments, the surface of the recess 231 facing the interior of the battery cell 20 is further from the interior of the battery cell 20 than the surface of the first protrusion 2135 facing the interior of the battery cell 20. For example... Figures 6 to 10 As shown, for the surface of the first wall 213 facing the interior of the battery cell 20, the first protrusion structure 2135 is closer to the interior of the battery cell 20 than the main structure 2134; at the same time, the surface of the recess 231 facing the interior of the battery cell 20 does not exceed the surface of the first protrusion structure 2135 facing the interior of the battery cell 20, that is, the first protrusion structure 2135 is closer to the interior of the battery cell 20 than the recess 231.

[0135] In this way, the first protrusion structure 2135 can protect the surface of the recess 231 facing the interior of the battery cell 20, reducing the impact of the internal components of the battery cell 20 on the pressure relief mechanism 23. For example, components inside the battery cell 20, such as electrode assemblies, may come into contact with the first protrusion structure 2135. Since the first protrusion structure 2135 is closer to the interior of the battery cell 20 than the recess 231, the contact between these components and the recess 231 can be reduced, thereby protecting the recess 231.

[0136] Furthermore, the first wall 213 is provided with a second groove 2132 with an opening facing the outside of the battery cell 20, and the bottom wall of the second groove 2132 is provided with a first groove 2131. The fixing area 242 is provided in the area surrounding the first groove 2131 on the bottom wall of the second groove 2132. Figures 6 to 10 As shown, the bottom wall of the second groove 2132 is provided with a first groove 2131, and the area of ​​the bottom wall of the second groove 2132 without the first groove 2131 surrounds the first groove 2131; correspondingly, the fixing area 242 provided around the edge of the protective piece 24 is fixed to the area of ​​the bottom wall of the second groove 2132 surrounding the first groove 2131 and is sealed together.

[0137] By providing the second groove 2132, at least a portion of the protective sheet 24 can be accommodated within the second groove 2132, reducing the portion of the protective sheet 24 protruding from the outermost surface of the first wall 213, thereby reducing the space occupied by the battery cell 20 and increasing the energy density of the battery device 10.

[0138] In some embodiments, the first wall 213 further includes a second protrusion structure 2136, which is located on the side of the bottom wall of the second groove 2132 facing the interior of the battery cell 20, and corresponds to the portion of the bottom wall of the second groove 2132 where the first groove 2131 is not provided. The second protrusion structure 2136 protrudes towards the interior of the battery cell 20 relative to the main structure 2134. Figures 6 to 10 As shown, the first wall 213 is provided with a first groove 2131 and a second groove 2132, which are typically processed by stamping. Considering that the base material of the first wall 213 is iron or titanium, the first wall 213 has high structural strength and is difficult to thin by stamping to obtain the first groove 2131 and the second groove 2132. Therefore, when the first groove 2131 and the second groove 2132 are obtained by stamping, a first protrusion structure 2135 is usually formed on the side of the bottom wall of the first groove 2131 facing the interior of the battery cell 20, and a second protrusion structure 2136 is usually formed on the side of the bottom wall of the second groove 2132 facing the interior of the battery cell 20 where the first groove 2131 is not provided, so as to facilitate the processing of the first groove 2131 and the second groove 2132.

[0139] And, as Figures 6 to 10 As shown, since the first groove 2131 is disposed on the bottom wall of the second groove 2132, for the surface of the first wall 213 facing the inside of the battery cell 20, the part of the main structure 2134 is further away from the inside of the battery cell 20 than the second protrusion structure 2136, and the second protrusion structure 2136 is further away from the inside of the battery cell 20 than the first protrusion structure 2135, so that the surface of the first wall 213 forms a stepped structure.

[0140] In some embodiments, along the thickness direction of the protective sheet 24, the depth L3 of the area where the fixing region 242 of the second groove 2132 is located is greater than or equal to the thickness L4 of the fixing region 242, so that the surface of the protective sheet 24 facing the outside of the battery cell 20 does not exceed the surface of the first wall 213 facing the outside of the battery cell 20. That is, the area where the pressure relief mechanism 23 and the protective sheet 24 are located on the first wall 213 does not protrude from the first wall 213. This can protect the pressure relief mechanism 23 and the protective sheet 24, reduce wear, and make the first wall 213 of the battery cell 20 relatively flat, which is convenient for fixing in the battery device 10 and improves the structural stability of the battery device 10.

[0141] It should be understood that, along the thickness direction of the protective sheet 24, the specific values ​​of the depth L3 of the area where the fixing region 242 of the second groove 2132 is located and the thickness L4 of the fixing region 242 can be set according to the actual application. For example, as Figures 6 to 10 As shown, in this embodiment of the application, the thickness direction of the protective sheet 24 is taken as the height direction Z of the battery cell 20.

[0142] In some embodiments, along the thickness direction of the protective sheet 24, the depth L3 of the region where the fixing area 242 of the second groove 2132 is located ranges from [0.1 mm to 0.5 mm]. Setting the depth L3 of the second groove 2132 to be greater than or equal to 0.1 mm facilitates the accommodation of the protective sheet 24; simultaneously limiting the depth L3 of the second groove 2132 to be less than or equal to 0.5 mm, when the thickness T of the first wall 213 is limited, reduces the processing difficulty of the second groove 2132 and improves the stability of the first wall 213.

[0143] Furthermore, along the thickness direction of the protective sheet 24, the depth L3 of the area where the fixing region 242 of the second groove 2132 is located is in the range of [0.15mm, 0.35mm]. This can accommodate the protective sheet 24, reduce the processing difficulty, and improve the processing efficiency of the battery cell 20.

[0144] In some embodiments, the depth L3 of the second groove 2132 may be any one of the following values ​​or between any two of the following values: 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm.

[0145] In some embodiments, the thickness L4 of the fixing region 242 along the thickness direction of the protective sheet 24 ranges from [0.05mm, 0.5mm]. Having a thickness L4 of the fixing region 242 greater than or equal to 0.05mm improves the structural strength of the protective sheet 24, thus better protecting the pressure relief mechanism 23 and facilitating the fixation between the fixing region 242 and the second groove 2132, thereby improving structural stability. Simultaneously, limiting the thickness L4 of the fixing region 242 to less than or equal to 0.5mm reduces the space occupied by the protective sheet 24, improves the space utilization of the battery cell 20, and consequently increases the energy density of the battery cell 20.

[0146] Furthermore, along the thickness direction of the protective sheet 24, the thickness L4 of the fixing area 242 ranges from [0.1mm, 0.3mm]. This can improve the structural strength of the fixing area 242 of the protective sheet 24, as well as improve the space utilization of the battery cell 20, thereby increasing the energy density of the battery cell 20.

[0147] In some embodiments, the thickness L4 of the fixing area 242 may be any one of the following values ​​or between any two of the following values: 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm.

[0148] It should be understood that the protective sheet 24 in this embodiment may also have a thinning region to reduce the thickness of the protective sheet 24, improve the space utilization of the battery cell 20, and thus improve the energy density of the battery cell 20. For example, the middle region of the protective sheet 24 may be provided with a groove with an opening facing the pressure relief mechanism 23, that is, the middle region of the protective sheet 24 can be a thinning region. On the one hand, the middle region is the region other than the fixing region 242, which has little impact on the connection stability between the protective sheet 24 and the first wall 213. On the other hand, the groove in the middle region of the protective sheet 24 can provide a receiving space for the protruding body portion 233, which can improve the space utilization of the battery cell 20.

[0149] It should be understood that the protective sheet 24 and the first wall 213 in this embodiment can be fixed in various ways. For example, the fixing area 242 of the protective sheet 24 and the bottom wall of the second groove 2132 of the first wall 213 can be fixed with an adhesive, which is simple to operate and easy to implement. The bonding dimensions between the fixing area 242 and the bottom wall of the second groove 2132 can be set according to the actual application.

[0150] In some embodiments, such as Figures 6 to 10As shown, the fixing area 242 and the bottom wall of the second groove 2132 are fixed together by an adhesive. Along the radial direction of the protective sheet 24, the adhesive bonding width L5 ranges from 0.5mm to 6mm. Setting the bonding width L5 to be greater than or equal to 0.5mm can improve the bonding stability between the fixing area 242 and the bottom wall of the second groove 2132; setting the bonding width L5 to be less than or equal to 6mm can limit the size of the protective sheet 24 and the second groove 2132, thereby improving the structural strength of the first wall 213.

[0151] Furthermore, the fixing area 242 and the bottom wall of the second groove 2132 are fixed together by an adhesive. Along the radial direction of the protective sheet 24, the adhesive bonding width L5 ranges from [2mm to 4.5mm]. This can improve the bonding stability between the fixing area 242 and the bottom wall of the second groove 2132, and also improve the structural strength of the first wall 213.

[0152] It should be understood that the adhesive width L5 can be calculated from one end of the protective sheet 24 facing the side wall of the second groove 2132. That is, when adhesive fixing area 242 and bottom wall of second groove 2132 are adhesively bonded, adhesive can be applied from one end of the protective sheet 24 facing the side wall of second groove 2132 to improve the structural strength and stability of the edge of the protective sheet 24. However, the embodiments of this application are not limited to this.

[0153] In some embodiments, the pasting width L5 may be any one of the following values ​​or between any two of the following values: 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 6mm.

[0154] In some embodiments, the distance L6 between the sidewall of the second groove 2132 and the surface of the protective sheet 24 facing the sidewall of the second groove 2132 is greater than or equal to 0.1 mm. Increasing the distance L6 between the sidewall of the second groove 2132 and the protective sheet 24, i.e., reserving an assembly gap between the protective sheet 24 and the first wall 213, allows the edge of the protective sheet 24 to also be accommodated within the second groove 2132, reducing the risk of the protective sheet 24 protruding from the outer surface of the first wall 213. This makes both the outer surface of the first wall 213 and the outer surface of the protective sheet 24 relatively flat, improving the stability and reliability of the battery cell 20.

[0155] It should be understood that the shape of the through hole 241 of the protective sheet 24 in this application embodiment can be set according to actual application. For example, the through hole 241 can be a circular hole or a square hole to facilitate processing. For example, as Figures 6 to 10 As shown, the embodiments of this application are mainly illustrated using a circular through hole 241 as an example.

[0156] It should be understood that the size of the through hole 241 of the protective sheet 24 in this application embodiment can be set according to actual application. For example, as Figures 6 to 10 As shown, the aperture R of the through hole 241 ranges from [0.1mm to 10mm]. Setting the aperture R of the through hole 241 to be greater than or equal to 0.1mm facilitates helium detection and improves detection accuracy; at the same time, limiting the aperture R of the through hole 241 to be less than or equal to 10mm increases the protection area of ​​the protective plate 24 for the pressure relief mechanism 23, thereby better protecting the pressure relief mechanism 23.

[0157] In some embodiments, the aperture R of the through hole 241 can also be other values. For example, the aperture R of the through hole 241 can be in the range of [0.5mm, 5mm], which facilitates helium detection and protects the pressure relief mechanism 23.

[0158] In some embodiments, the aperture R of the through hole 241 can be any one of the following values ​​or between any two of the following values: 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm.

[0159] In some embodiments, along the thickness direction of the protective sheet 24, the distance between the orthographic projection of the area of ​​the recess 231 that is furthest from the protective sheet 24 and the center of the through hole 241 ranges from [0 mm to 20 mm]. A smaller distance L1 means that, radially, the center of the through hole 241 is closer to the area of ​​the largest recess in the recess 231, resulting in a larger space on the side of the through hole 241 facing the recess 231, providing a flow channel for leaked helium during helium detection. Especially when the body portion 233 protrudes outwards, a smaller distance L1 means that radially, the through hole 241 is further away from the center of the body portion 233, reducing the risk of the through hole 241 being blocked by the protruding body portion 233. Thus, during helium detection, if the pressure relief mechanism 23 leaks, the through hole 241 is more likely to detect the leaked helium, thereby improving the accuracy of the detection.

[0160] like Figures 6 to 10As shown, when a groove is provided in the area of ​​the recess 231 where the distance from the protective plate 24 is greatest, for example, if a groove is provided on the bottom wall of the recess 231, then the aforementioned distance L1 can be the distance between the orthographic projection of the area with the smallest thickness of the groove toward the protective plate 24 and the center of the through hole 241. The smaller this distance L1 is, the closer the center of the through hole 241 is to the groove in the radial direction of the through hole 241, and the thinner the groove, making it more prone to helium leakage. Thus, during helium detection, if a leak occurs at the relatively thin groove, the through hole 241, which is closer to the groove, is more likely to detect the leaked helium, thereby improving the accuracy of the detection.

[0161] Furthermore, the value of distance L1 is set to [0mm, 10mm]. This further restricts the value of L1, which facilitates the passage of helium gas and can further improve the accuracy of detection.

[0162] In some embodiments, the distance L1 can also be any one of the following values ​​or between any two of the following values: 0mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm.

[0163] It should be understood that if the weak area 2311 is not a notch, for example, if the weak area 2311 is a temperature-sensitive material, then the aforementioned distance L1 can also refer to the distance between the orthographic projection of the weakest area of ​​the weak area 2311 toward the protective sheet 24 and the center of the through hole 241.

[0164] It should be understood that when the aforementioned distance L1 is not equal to 0 mm, taking the case where the weak area 2311 of the recess 231 is a notch as an example, the notch of the weak area 2311 is offset relative to the center of the through hole 241 along the radial direction of the through hole 241. For example, Figures 6 to 9 As shown, along the radial direction of the through hole 241, the weak area 2311 can be offset outward, that is, the weak area 2311 can be located outside the center of the through hole 241, or, unlike... Figures 6 to 9 The weak area 2311 can be offset inward, that is, the weak area 2311 can also be located inside the center of the through hole 241. The embodiments of this application are not limited to this.

[0165] It should be understood that the distance between the recess 231 and the surface of the protective sheet 24 facing the recess 231 can be set according to the actual application. For example, along the thickness direction of the protective sheet 24, the maximum distance L2 between the recess 231 and the protective sheet 24 can range from 0.05mm to 3mm. Setting this distance L2 to be greater than or equal to 0.05mm provides a certain gap between the recess 231 and the protective sheet 24. This gap can provide a channel for helium flow if the recess 231 leaks during helium detection, allowing for the detection of whether the pressure relief mechanism 23 is leaking through the through-hole 241. This reduces the likelihood of the protective sheet 24 obstructing helium detection, thereby improving the accuracy of the detection. At the same time, limiting this distance L2 to less than or equal to 3mm reduces the space between the protective sheet 24 and the pressure relief mechanism 23, improving the space utilization of the battery cell 20 and thus increasing the energy density.

[0166] It should be understood that, such as Figures 6 to 10 As shown, taking the recess 231 as an approximate groove structure as an example, the maximum distance L2 between the recess 231 and the protective sheet 24 along the thickness direction of the protective sheet 24 is usually the distance between the bottom wall of the recess 231 and the protective sheet 24. If the bottom wall of the recess 231 is provided with a weak area 2311, and the weak area 2311 is a groove, the distance L2 is usually the maximum distance between the recess 231 and the protective sheet 24 in the area where the bottom wall of the recess 231 is not provided with a groove.

[0167] Furthermore, the minimum distance L2 between the recess 231 and the surface of the protective sheet 24 facing the recess 231 can also be in the range of [0.2mm, 2mm]. Increasing the gap between the recess 231 and the protective sheet 24 improves the flow of depressurized helium gas, thereby further improving detection accuracy; at the same time, further reducing the space between the protective sheet 24 and the depressurization mechanism 23 can increase the energy density of the battery cell 20.

[0168] In some embodiments, the distance L2 may be any one of the following values ​​or between any two of the following values: 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, 2.8mm, or 3mm.

[0169] It should be understood that the protective sheet 24 in this embodiment may include one or more through holes 241, and the specific number of through holes 241 can be set according to the actual application. For example, the number of through holes 241 can be set according to the size of the pressure relief mechanism 23. For example, the larger the size of the pressure relief mechanism 23, the more through holes 241 there are, so as to improve the accuracy of helium detection.

[0170] In some embodiments, the protective sheet 24 is provided with two through holes 241, which are radially symmetrically distributed with respect to the protective sheet 24. Considering that the pressure relief mechanism 23 is generally a symmetrical structure, for example, the recess 231 of the pressure relief mechanism 23 is also a symmetrical structure, the two symmetrical through holes 241 are correspondingly provided to make the through holes 241 relatively uniformly distributed, thereby improving the accuracy of detection. For example, two opposing through holes 241 can be provided along the length direction of the protective sheet 24, but the embodiments of this application are not limited to this.

[0171] According to some embodiments of this application, this application also provides a battery device including a battery cell 20 as described in any of the above embodiments.

[0172] According to some embodiments of this application, this application also provides an electrical device including the battery device described in any of the above embodiments, and the battery device is used to provide electrical energy to the electrical device.

[0173] The electrical equipment can be any of the aforementioned devices or systems that utilize battery devices.

[0174] According to some embodiments of this application, see Figures 3 to 10 This application provides a battery cell 20, which includes: a housing 21, a pressure relief mechanism 23, and a protective sheet 24. The housing 21 has a first wall 213, the base material of the first wall 213 being iron or titanium; the pressure relief mechanism 23 is disposed on the first wall 213; the protective sheet 24 is disposed on the side of the pressure relief mechanism 23 away from the interior of the battery cell and covers the pressure relief mechanism 23, the protective sheet 24 includes a fixing area 242 disposed around the edge of the protective sheet 24, the fixing area 242 is fixed to the first wall 213 and is sealed to the first wall 213, and the area of ​​the protective sheet 24 other than the fixing area 242 is provided with a through hole 241.

[0175] The pressure relief mechanism 23 includes a recess 231, which is recessed towards the interior of the battery cell 20 relative to the protective sheet 24, and a through hole 241 corresponds to the recess 231. A pressure relief hole 2133 is provided on the first wall 213, and the pressure relief mechanism 23 covers the pressure relief hole 2133, with at least a portion of the recess 231 accommodated within the pressure relief hole 2133. The pressure relief mechanism 23 also includes a connecting portion 232, which is located outside the recess 231 along the radial direction of the pressure relief mechanism 23 and connects to the area surrounding the pressure relief hole 2133 of the first wall 213. The connecting portion 232 is arranged parallel to the first wall 213, and the recess 231 is recessed towards the interior of the battery cell 20 relative to the connecting portion 232. The pressure relief mechanism 23 also includes a body portion 233, which is located within the area surrounded by the recess 231 and protrudes towards the interior away from the battery cell 20 relative to the recess 231.

[0176] The first wall 213 has a first groove 2131 with an opening facing the outside of the battery cell 20. The bottom wall of the first groove 2131 has a pressure relief hole 2133. A connecting portion 232 is disposed in the area surrounding the pressure relief hole 2133 on the bottom wall of the first groove 2131. The first wall 213 includes a main structure 2134 and a first protrusion 2135. The first protrusion 2135 is located on the side of the bottom wall of the first groove 2131 facing the inside of the battery cell 20, and protrudes towards the inside of the battery cell 20 relative to the main structure 2134. The surface of the groove 231 facing the inside of the battery cell 20 is further away from the inside of the battery cell 20 than the surface of the first protrusion 2135 facing the inside of the battery cell 20.

[0177] The first wall 213 has a second groove 2132 with an opening facing the outside of the battery cell 20. The bottom wall of the second groove 2132 has a first groove 2131. The fixing area 242 is located in the area surrounding the first groove 2131 on the bottom wall of the second groove 2132. Along the thickness direction of the protective sheet 24, the depth of the area of ​​the second groove 2132 where the fixing area 242 is located is greater than or equal to the thickness of the fixing area 242.

[0178] Along the thickness direction of the protective sheet 24, the area of ​​the recess 231 that is furthest from the protective sheet 24 is provided with a weak area 2311. The weak area 2311 is designed to be broken to release pressure when the pressure inside the battery cell 20 reaches a threshold.

[0179] Along the thickness direction of the protective sheet 24, the distance between the orthographic projection of the area of ​​the recess 231 that is furthest from the protective sheet 24 and the center of the through hole 241 ranges from [0 mm to 20 mm]. Along the thickness direction of the protective sheet 24, the maximum distance between the recess 231 and the protective sheet 24 ranges from [0.05 mm to 3 mm]. The substrate of the pressure relief mechanism 23 is the same as the substrate of the first wall 213.

[0180] 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 (21) has a first wall (213) and the substrate of the first wall (213) is iron or titanium; Pressure relief mechanism (23), wherein the pressure relief mechanism (23) is disposed on the first wall (213); A protective sheet (24) is disposed on the side of the pressure relief mechanism (23) away from the interior of the battery cell and covers the pressure relief mechanism (23). The protective sheet (24) includes a fixing area (242) disposed around the edge of the protective sheet (24). The fixing area (242) is fixed to the first wall (213) and is sealed to the first wall (213). The area of ​​the protective sheet (24) other than the fixing area (242) is provided with a through hole (241).

2. The battery cell according to claim 1, characterized in that, The pressure relief mechanism (23) includes a recess (231) that is recessed toward the interior of the battery cell relative to the protective sheet (24), and the through hole (241) corresponds to the recess (231).

3. The battery cell according to claim 2, characterized in that, The first wall (213) is provided with a pressure relief hole (2133), the pressure relief mechanism (23) covers the pressure relief hole (2133), and at least a portion of the recess (231) is accommodated within the pressure relief hole (2133).

4. The battery cell according to claim 3, characterized in that, The pressure relief mechanism (23) further includes a connecting portion (232). Along the radial direction of the pressure relief mechanism (23), the connecting portion (232) is located outside the recess (231) and connects to the area around the pressure relief hole (2133) of the first wall (213). The connecting portion (232) is arranged parallel to the first wall (213), and the recess (231) is recessed towards the interior of the battery cell relative to the connecting portion (232).

5. The battery cell according to claim 4, characterized in that, The pressure relief mechanism (23) further includes a body portion (233) located in the area surrounded by the recess (231), the body portion (233) protruding towards the interior away from the battery cell relative to the recess (231).

6. The battery cell according to claim 4, characterized in that, The first wall (213) is provided with a first groove (2131) with an opening facing the outside of the battery cell. The bottom wall of the first groove (2131) is provided with the pressure relief hole (2133). The connecting part (232) is provided in the area surrounding the pressure relief hole (2133) on the bottom wall of the first groove (2131).

7. The battery cell according to claim 6, characterized in that, The first wall (213) includes a main structure (2134) and a first protrusion structure (2135). The first protrusion structure (2135) is located on the side of the bottom wall of the first groove (2131) facing the interior of the battery cell. The first protrusion structure (2135) protrudes towards the interior of the battery cell relative to the main structure (2134).

8. The battery cell according to claim 7, characterized in that, The surface of the recess (231) facing the interior of the battery cell is further away from the interior of the battery cell than the surface of the first protrusion (2135) facing the interior of the battery cell.

9. The battery cell according to claim 6, characterized in that, The first wall (213) is provided with a second groove (2132) with an opening facing the outside of the battery cell. The bottom wall of the second groove (2132) is provided with the first groove (2131). The fixing area (242) is provided in the area surrounding the first groove (2131) on the bottom wall of the second groove (2132).

10. The battery cell according to claim 9, characterized in that, The first wall (213) includes a main structure (2134) and a second protrusion structure (2136). The second protrusion structure (2136) is located on the side of the bottom wall of the second groove (2132) facing the interior of the battery cell. The second protrusion structure (2136) corresponds to the part of the bottom wall of the second groove (2132) where the first groove (2131) is not provided. The second protrusion structure (2136) protrudes towards the interior of the battery cell relative to the main structure (2134).

11. The battery cell according to claim 9, characterized in that, Along the thickness direction of the protective sheet (24), the depth of the area of ​​the second groove (2132) where the fixing area (242) is located is greater than or equal to the thickness of the fixing area (242).

12. The battery cell according to claim 11, characterized in that, Along the thickness direction of the protective sheet (24), the depth of the area of ​​the second groove (2132) where the fixing area (242) is located ranges from [0.1mm, 0.5mm].

13. The battery cell according to claim 11, characterized in that, Along the thickness direction of the protective sheet (24), the thickness of the fixing area (242) ranges from [0.05mm, 0.5mm].

14. The battery cell according to claim 9, characterized in that, The fixing area (242) is fixed to the bottom wall of the second groove (2132) by an adhesive. The adhesive bonding width ranges from 0.5 mm to 6 mm along the radial direction of the protective sheet (24).

15. The battery cell according to claim 9, characterized in that, The distance between the sidewall of the second groove (2132) and the surface of the protective sheet (24) facing the sidewall of the second groove (2132) is greater than or equal to 0.1 mm.

16. The battery cell according to claim 2, characterized in that, The recess (231) is provided with a weak area (2311), which is designed to be broken when the pressure inside the battery cell reaches a threshold in order to release the pressure.

17. The battery cell according to claim 2, characterized in that, Along the thickness direction of the protective sheet (24), the distance between the orthographic projection of the recess (231) that is furthest from the protective sheet (24) toward the protective sheet (24) and the center of the through hole (241) ranges from [0 mm to 20 mm].

18. The battery cell according to claim 2, characterized in that, Along the thickness direction of the protective sheet (24), the maximum distance between the recess (231) and the protective sheet (24) ranges from [0.05mm, 3mm].

19. The battery cell according to any one of claims 1 to 18, characterized in that, The substrate of the pressure relief mechanism (23) is the same as the substrate of the first wall (213).

20. The battery cell according to any one of claims 1 to 18, characterized in that, The diameter of the through hole (241) ranges from [0.1 mm to 10 mm].

21. The battery cell according to any one of claims 1 to 18, characterized in that, The protective sheet (24) is provided with two through holes (241), which are radially symmetrically distributed with respect to the protective sheet (24).

22. The battery cell according to any one of claims 1 to 18, characterized in that, The outer casing (21) includes: The shell (211) has a hollow structure with an opening (2111), and the first wall (213) is the bottom wall of the shell (211); A cover plate (212) is used to cover the opening (2111).

23. A battery device, characterized in that, include: Multiple battery cells, wherein the battery cells are battery cells as described in any one of claims 1 to 22.

24. An electrical appliance, characterized in that, include: A battery device comprising a battery cell as described in any one of claims 1 to 22, the battery device being used to supply power to the electrical device.

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