Battery devices and electrical equipment

Abstract

This application provides a battery device and an electrical appliance. The battery device includes a housing and multiple battery cell groups. The housing has a receiving cavity. The multiple battery cell groups are disposed in the receiving cavity and arranged along a first direction. Each battery cell group includes multiple battery cells arranged along a second direction, which is perpendicular to the first direction and parallel to the thickness direction of the battery cells. The dimension of the receiving cavity along the second direction is larger than the dimension of the receiving cavity along the first direction. Each battery cell includes a housing and at least one electrode assembly disposed within the housing. The at least one electrode assembly is arranged along the second direction and has a wound structure, including a straight region and two bent regions connected to the straight region, with the two bent regions respectively disposed on both sides of the straight region along the first direction. The ratio of the total dimension of the bent regions arranged along the first direction to the dimension of the receiving cavity in the first direction is 2.4%-10.2%.

Description

Technical Field

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

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

[0003] In the development of battery technology, improving the energy density of battery devices is a research direction. Utility Model Content

[0004] This application provides a battery device and an electrical appliance that can improve energy density.

[0005] In a first aspect, embodiments of this application provide a battery device, which includes a housing and a plurality of battery cell groups. The housing has a receiving cavity. The plurality of battery cell groups are disposed in the receiving cavity and arranged along a first direction. Each battery cell group includes a plurality of battery cells arranged along a second direction, the second direction being perpendicular to the first direction and parallel to the thickness direction of the battery cells. The dimension of the receiving cavity along the second direction is larger than the dimension of the receiving cavity along the first direction. Each battery cell includes a housing and at least one electrode assembly disposed within the housing. The at least one electrode assembly is arranged along the second direction, and the electrode assembly has a wound structure, including a straight region and two bent regions connected to the straight region, the two bent regions being respectively disposed on both sides of the straight region along the first direction. The ratio of the total dimension of the bent regions arranged along the first direction to the dimension of the receiving cavity in the first direction is 2.4%-10.2%.

[0006] In this embodiment, setting W2 / W1 to less than or equal to 10.2% reduces the space occupied by the bending area in the first direction, thereby improving the space utilization rate of the battery device in the first direction. Similarly, setting W2 / W1 to greater than or equal to 2.4% reduces the space occupied by the casing in the second direction, further improving the space utilization rate of the battery device in the second direction. In summary, setting W2 / W1 to 2.4%-10.2% in this embodiment can, to a certain extent, balance the space utilization rate of the battery device in both the first and second directions, thereby improving the volumetric energy density of the battery device.

[0007] In some embodiments, the ratio of the total dimension of the bending regions arranged along the first direction to the dimension of the receiving cavity in the first direction is 3%-7%. Embodiments of this application can further balance the space utilization rate of the battery device in the first direction and the space utilization rate in the second direction, thereby improving the volumetric energy density of the battery device.

[0008] In some embodiments, the number of battery cells is 3 or 4. Arranging the battery cells in 3 or 4 columns in this application embodiment can balance the space utilization of the battery device in both the first and second directions, thereby improving the volumetric energy density of the battery device.

[0009] In some embodiments, the number of electrode assemblies in a single battery cell is 2 or 4.

[0010] In some embodiments, the ratio of the dimension of the receiving cavity along the second direction to the dimension of the battery cell along the second direction is 30-84. The embodiments of this application can, to a certain extent, balance the space utilization rate of the battery device in the first direction and the space utilization rate in the second direction, thereby improving the volumetric energy density of the battery device.

[0011] In some embodiments, the housing includes two first walls disposed opposite each other along a first direction and two second walls disposed opposite each other along a second direction, with each first wall connecting to the two second walls.

[0012] In some embodiments, the thickness of the second wall is less than the thickness of the first wall. When the electrode assembly expands, the thinner second wall can undergo slight elastic deformation to release expansion stress, thereby reducing the risk of casing cracking. Compared to the second wall, the first wall can have a larger thickness, thereby improving the impact resistance of the battery cell sides and reducing the risk of casing breakage in the event of collisions, drops, or other accidents involving the battery device. Since the number of battery cells is relatively small, using a thicker first wall has a minimal impact on the energy density of the battery device.

[0013] In some embodiments, the thickness of the second wall is 0.3mm-0.8mm, and the thickness of the first wall is 0.5mm-1.2mm. The embodiments of this application can, to a certain extent, balance the strength of the outer casing and the space occupied by the outer casing.

[0014] In some embodiments, the ratio of the total dimension W4 of the first walls arranged along the first direction to the dimension W1 of the receiving cavity in the first direction is 0.2%-1%. In this application embodiment, W4 / W1 is set to be greater than or equal to 0.2% to improve the strength of the first walls and reduce the risk of breakage. In this application embodiment, W4 / W1 is set to be less than or equal to 1% to reduce the space occupied by the first walls in the first direction, improve the space utilization of the battery device in the first direction, and increase the volumetric energy density of the battery device.

[0015] In some embodiments, the ratio of the total dimension L3 of the second wall of the battery cell assembly in the second direction to the dimension L1 of the receiving cavity in the second direction is 1.0%-4.5%.

[0016] In this embodiment, setting L3 / L1 to be greater than or equal to 1.0% can improve the strength of the second wall and reduce the risk of its breakage. Setting L3 / L1 to less than or equal to 4.5% can reduce the space occupied by the second wall in the second direction. With a fixed thickness of the second wall, setting L3 / L1 to 1.0%-4.5% can, to a certain extent, balance the space utilization rate of the battery device in both the first and second directions, thereby improving the volumetric energy density of the battery device.

[0017] In some embodiments, the size of the receiving cavity along the first direction is 900mm-1400mm, and the size of the receiving cavity along the second direction is 1300mm-2100mm.

[0018] In some embodiments, the ratio of the total dimension L4 of all electrode components of the battery cell assembly along the second direction to the dimension L1 of the receiving cavity along the second direction is greater than or equal to 77%. Embodiments of this application can enable the battery device to have higher space utilization in the second direction, thereby improving the energy density of the battery device.

[0019] In some embodiments, the ratio of the total dimension of the electrode assembly arranged along the first direction to the dimension of the receiving cavity in the first direction is greater than or equal to 90%. Embodiments of this application can enable the battery device to have higher space utilization in the first direction, thereby improving the energy density of the battery device.

[0020] In some embodiments, the housing includes a third wall disposed on one side of the electrode assembly along a third direction, the third direction being perpendicular to the second and first directions. The battery cell also includes electrode terminals, a retainer, and a first insulating member. The electrode terminals are disposed on the third wall and electrically connected to the electrode assembly. The retainer is disposed around the electrode terminals and includes a base and a limiting portion. The base is connected to the third wall, and the limiting portion is connected to the base and extends in a direction proximate to the electrode terminals. The limiting portion is configured to restrict movement of the electrode terminals in a direction away from the electrode assembly along the third direction. At least a portion of the first insulating member is disposed between the electrode terminals and the limiting portion.

[0021] In this embodiment, the fixing member is disposed on the periphery of the electrode terminal, which can restrict the movement of the electrode terminal from the outer periphery; the limiting part and the third wall can cooperate to clamp the electrode terminal to restrict the movement of the electrode terminal in the third direction. This embodiment, by providing the fixing member to fix the electrode terminal to the third wall, simplifies the structure of the battery cell. The first insulating member can insulate and isolate the limiting part of the fixing member and the electrode terminal, thereby achieving insulation isolation between the electrode terminal and the limiting part of the fixing member.

[0022] In some embodiments, the thickness of the limiting portion is less than the thickness of the base portion.

[0023] Compared to the limiting portion, the base can have a larger thickness, which is beneficial for improving the connection quality and strength between the base and the third wall. The limiting portion is used to limit the electrode terminal in a third direction. It does not need to be directly fixed to the electrode terminal, therefore, the limiting portion can have a smaller thickness compared to the base. By reducing the thickness of the limiting portion, the space between the limiting portion and the electrode terminal for accommodating the first insulating member can be increased. This allows for an increase in the thickness of the portion of the first insulating member disposed between the limiting portion and the electrode terminal, increasing the creepage distance between the limiting portion and the electrode terminal. This helps reduce the short-circuit risk of the battery cell during use, thereby improving the reliability of the battery cell.

[0024] In some embodiments, along a third direction, a portion of the electrode terminal is located between the limiting portion and the third wall. The portion of the limiting portion and the portion of the third wall are respectively located on opposite sides of the portion of the electrode terminal in the third direction, thereby improving the effectiveness of the limiting portion and the third wall in clamping and assembling the electrode terminal, and enhancing the stability and reliability of the electrode terminal.

[0025] In some embodiments, along a third direction, the surface of the limiting portion facing the third wall is further away from the third wall than the surface of the base facing the third wall, and the surface of the limiting portion away from the third wall is further away from the third wall than the surface of the base away from the third wall. The fastener also includes a connecting portion that connects the base and the limiting portion.

[0026] By setting a connecting part between the base and the limiting part, on the one hand, it is beneficial to reduce the connection difficulty between the base and the limiting part and improve the connection stability between the base and the limiting part. On the other hand, while achieving the pressing of the electrode terminal by the limiting part and meeting the connection quality between the base and the third wall, it is not necessary to increase the thickness of the base in the third direction, which helps to reduce the manufacturing cost of the fastener and can reduce the weight of the fastener.

[0027] In some embodiments, the fastener has a thinning groove on the side facing the third wall in a third direction, the limiting portion includes the bottom surface of the thinning groove, and the connecting portion includes the side surface of the thinning groove. A portion of the first insulating member is disposed in the thinning groove. By providing the thinning groove, more space can be provided for the first insulating member, thereby increasing the creepage distance and reducing the risk of insulation failure.

[0028] In some embodiments, the electrode terminal includes a body portion and an assembly portion. The body portion is electrically connected to the electrode assembly, and the assembly portion protrudes from the outer peripheral surface of the body portion. A portion of the assembly portion is located between a limiting portion and a third wall in a third-dimensional direction. A portion of a first insulating member is located between the limiting portion and the outer peripheral surface of the body portion. By providing the assembly portion, a portion of the electrode terminal can extend between the third wall and the limiting portion, thereby improving the stability of the electrode terminal. The first insulating member can insulate and isolate the limiting portion and the body portion, thereby reducing the risk of short circuits.

[0029] In some embodiments, the fastener includes a first material layer and a second material layer connected to each other. At least a portion of the first material layer is located within the base and is connected to the third wall. At least a portion of the second material layer is located within the limiting portion, and the hardness of the second material layer is greater than that of the first material layer.

[0030] In this embodiment, the material of the first material layer can be the same as or similar to the material of the third wall, so that the fastener can be connected to the third wall through the portion of the first material layer located within the base, which helps to reduce the connection difficulty between the fastener and the third wall. By disposing at least a portion of the second material layer, which has higher hardness, within the limiting portion, the structural strength of the limiting portion can be improved, reducing the risk of breakage or deformation, thereby improving the assembly effect of the fastener on the electrode terminals. In the case of a limiting portion with the same strength, disposing at least a portion of the second material layer, which has higher hardness, within the limiting portion can further reduce the thickness of the limiting portion, which helps to further optimize the dimensions of the fastener in the third direction.

[0031] In some embodiments, a portion of the first material layer is located within the limiting portion, and in the limiting portion, the first material layer and the second material layer at least partially overlap in a third direction. By overlapping the first and second material layers in the limiting portion, this embodiment increases the contact area between the first and second material layers within the limiting portion, thereby reducing the connection difficulty between the first and second material layers within the limiting portion, strengthening the mutual constraint between the first and second material layers within the limiting portion, and further improving the structural strength of the limiting portion.

[0032] In some embodiments, a portion of the second material layer is located within the base, where the first and second material layers at least partially overlap in a third direction. This application embodiment facilitates connection between the base and the third wall by providing the first material layer within the base, and enhances the structural strength of the base by providing the second material layer, thereby reducing the risk of breakage or deformation and improving the overall structural strength of the fastener. The overlapping arrangement of the first and second material layers within the base increases the contact area between them, thus improving the connection strength.

[0033] In some embodiments, along a third direction, the second material layer is located on the side of the first material layer facing the third wall. By setting the second material layer to be located on the side of the first material layer facing the third wall, it is beneficial to improve the structural strength of the limiting part facing the third wall, thereby facilitating the assembly of the electrode terminal by the fixing member and improving the structural stability of the electrode terminal assembled on the third wall.

[0034] In some embodiments, a first material layer and a second material layer are stacked, and along the stacking direction of the first material layer and the second material layer, the thickness of the first material layer is greater than the thickness of the second material layer.

[0035] By setting the thickness of the first material layer to be greater than that of the second material layer, it is beneficial to increase the thickness of the area at the base used for interconnection with the third wall, thereby improving the stability and reliability of the connection between the fastener and the third wall. By setting the thickness of the second material layer to be less than that of the first material layer, the amount of the second material layer can be reduced while ensuring that the strength of the fastener meets the requirements.

[0036] In some embodiments, the hardness of the first material layer is greater than or equal to 30 kgf / mm². 2 And less than or equal to 170 kgf / mm 2 .

[0037] In some embodiments, the hardness of the second material layer is greater than or equal to 100 kgf / mm². 2 And less than or equal to 500 kgf / mm 2 .

[0038] In some embodiments, the material of the first material layer is the same as the material of the third wall, and the first material layer located within the base is welded to the third wall. By setting the material of the first material layer and the material of the third wall to be the same, a structure in which the base and the third wall are welded to the same material is achieved. This helps to reduce the welding difficulty between the first material layer and the third wall within the base, and can reduce welding defects between the base and the third wall, thereby improving the welding quality between the third wall and the base of the fastener.

[0039] In some embodiments, the housing includes a third wall disposed on one side of the electrode assembly along a third direction, which is perpendicular to both the second and first directions. The third wall includes a first wall body and a first protrusion. The first protrusion protrudes from the outer surface of the first wall body along the third direction. A recess is provided on the side of the third wall facing the electrode assembly, corresponding to the position of the first protrusion and recessed relative to the surface of the first wall body facing the electrode assembly. The electrode assembly also includes a tab extending from one end of the flat region facing the third wall. In the same plane perpendicular to the third direction, the orthographic projection of the tab at least partially overlaps with the orthographic projection of the recess. By providing the recess, clearance space can be provided for the tab, reducing the risk of interference between the tab and the first wall body, and decreasing the distance between the first wall body and the flat region, thereby improving space utilization. By providing the outwardly protruding first protrusion, the depth of the recess can be increased.

[0040] In some embodiments, a portion of the tab is accommodated within a recess. The tab and the first protrusion may share a portion of space in a third-direction orientation, thereby improving space utilization and increasing the energy density of the battery cell.

[0041] In some embodiments, the electrode assembly includes a negative electrode sheet, which includes a negative electrode active material layer. The ratio of the dimension H2 of the negative electrode active material layer along a third direction to the minimum dimension H3 of the casing along a third direction is 90%-93%. In this application embodiment, setting H2 / H3 to greater than or equal to 90% can increase the utilization rate of the internal space of the casing and improve the energy density of the battery cell. In this application embodiment, setting H2 / H3 to less than or equal to 93% allows for the reservation of installation space for other components of the battery cell.

[0042] In some embodiments, the recess extends through the third wall in a second direction to form first openings at both ends. The housing includes two second walls disposed opposite each other in the second direction, which are connected to the third wall and close the first openings of the recess. By providing a recess that extends through the third wall in this application embodiment, the size of the recess in the second direction and the internal space of the housing can be increased. Using the second walls to close the first openings of the recess simplifies the structure of the first walls.

[0043] In some embodiments, the battery cell further includes electrode terminals and an adapter. The electrode terminals are disposed on the first wall body, and the adapter is connected to the electrode terminals. At least a portion of the adapter is received within a recess and connected to a tab. Utilizing the recess to receive at least a portion of the adapter can improve space utilization. In the third direction, the electrode terminals can share a portion of the space with the first protrusion, thereby reducing the maximum size of the battery cell in the third direction and improving space utilization.

[0044] In some embodiments, the housing includes a third wall disposed on one side of the electrode assembly along a third direction, which is perpendicular to both the second and first directions. The electrode assembly also includes tabs extending from one end of the flat region facing the third wall. The battery cell also includes electrode terminals disposed on the third wall, with the tabs electrically connected to the electrode terminals. In the same plane perpendicular to the third direction, the orthographic projections of the electrode terminals and the tabs at least partially overlap. The ratio of the minimum distance D between the flat region and the electrode terminals along the third direction to the dimension H1 of the housing along the third direction is 3%-7%.

[0045] In this embodiment, D / H1 is set to greater than or equal to 3% to allow for a larger bending space for the tabs, reducing the risk of the tabs being inserted backwards into the straight area and improving reliability. In this embodiment, D / H1 is set to less than or equal to 7%, which reduces the space occupied by the tabs in the third-party upward direction and improves space utilization. In this embodiment, D / H1 is set to 3%-7%, which can, to a certain extent, balance the reliability and energy density of the battery cells.

[0046] Secondly, embodiments of this application provide an electrical device that includes a battery device provided in any of the embodiments of the first aspect, the battery device being used to provide electrical energy. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0048] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0049] Figure 2 Schematic diagram of a battery device provided for some embodiments of this application;

[0050] Figure 3 Schematic diagram of a battery device provided for some embodiments of this application;

[0051] Figure 4 An exploded schematic diagram of a single battery cell in a battery device provided in some embodiments of this application;

[0052] Figure 5 A cross-sectional schematic diagram of a battery cell for a battery device provided in some embodiments of this application;

[0053] Figure 6 A cross-sectional schematic diagram of the electrode assembly of a battery device provided in some embodiments of this application;

[0054] Figure 7 An exploded schematic diagram of a single battery cell of a battery device provided in other embodiments of this application;

[0055] Figure 8 A cross-sectional schematic diagram of a battery cell for a battery device provided in other embodiments of this application;

[0056] Figure 9 for Figure 8 Enlarged view of the area within the circle;

[0057] Figure 10 A partial cross-sectional schematic diagram of the fixing member of the battery cell of the battery device provided in other embodiments of this application;

[0058] Figure 11 A partial cross-sectional schematic diagram of a battery cell for another embodiment of the battery device provided in this application;

[0059] Figure 12 for Figure 11 A partial sectional view of the fastener shown;

[0060] Figure 13 A schematic diagram of the structure of a single battery cell for a battery device provided in some embodiments of this application;

[0061] Figure 14 for Figure 13 The diagram shows an exploded battery cell;

[0062] Figure 15 for Figure 13 A partial cross-sectional view of a single battery cell is shown.

[0063] Figure 16 A cross-sectional schematic diagram of the negative electrode sheet of a battery cell in a battery device provided in some embodiments of this application;

[0064] Figure 17 This is an exploded schematic diagram of a battery cell of a battery device provided in some embodiments of this application.

[0065] The annotations in the attached figures are explained as follows:

[0066] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Battery cell pack; 6. Housing; 6a. First housing; 6b. Second housing; 6c. Receiving cavity; 7. Battery cell;

[0067] 10. Electrode assembly; 10a. Straight region; 10b. Bending region; 10c. Tab; 11. Positive electrode plate; 12. Negative electrode plate; 121. Negative electrode current collector; 122. Negative electrode active material layer; 13. Separator;

[0068] 20. Outer shell; 20a. Housing; 20b. End cap; 21. First wall; 22. Second wall; 221. Second wall body; 222. Second protrusion; 23. Third wall; 231. First wall body; 232. First protrusion; 2321. Top; 2322. Side; 233. Recess; 233a. First opening; 233b. Second opening; 23a. Terminal hole; 23b. Assembly slot; 24. Fourth wall;

[0069] 30. Pressure relief mechanism; 40. Electrode terminal; 41. Body part; 42. Assembly part;

[0070] 50. Fastener; 50a. First material layer; 50b. Second material layer; 50c. Welding part; 51. Base; 52. Limiting part; 53. Connecting part; 531. Bending section; 532. Straight section; 54. Thinning groove;

[0071] 60. First insulating component; 61. Second insulating component; 62. Third insulating component; 63. Fourth insulating component; 70. Adapter component;

[0072] X, second direction; Y, first direction; Z, third direction. Detailed Implementation

[0073] 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.

[0074] 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.

[0075] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In this application, "multiple" means two or more (including two).

[0080] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0081] A single battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0082] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0083] A single battery cell typically includes an electrode assembly and a housing for containing the electrode assembly. Electrode assemblies with a wound structure often form both flat and bent regions. Compared to the flat regions, the bent regions have lower space utilization. In related technologies, the arrangement of battery cells in battery devices does not take the bent regions into account, resulting in a lower volumetric energy density of the battery device.

[0084] In view of this, the present application provides a technical solution that rationally designs the bending area and the internal space of the battery box to increase the space utilization rate of the battery device and improve the volumetric energy density of the battery device.

[0085] The battery cells described in this application are applicable to battery devices and electrical equipment using battery devices. Electrical equipment can be devices that use battery devices as a power source or various energy storage systems that use battery devices as energy storage elements. Electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0086] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0087] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0088] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0089] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0090] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0091] Figure 2 A schematic diagram of a battery device provided for some embodiments of this application.

[0092] In some embodiments, the battery device 2 may include a plurality of battery cell groups 5, which may be used to provide voltage and capacity.

[0093] The battery cell pack 5 may include multiple battery cells 7, which are connected in series, parallel, or mixed connection via a busbar. Mixed connection means that multiple battery cells 7 are connected in both series and parallel.

[0094] The battery cell 7 can be a secondary battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0095] As an example, the battery cell 7 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0096] As an example, the battery cell 7 can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include square battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0097] In some embodiments, the battery device 2 may be a battery pack, which includes a housing 6 and one or more battery cell groups 5, the battery cell groups 5 being housed in the housing 6.

[0098] In some embodiments, the housing 6 is used to house the battery cell 7, and the housing 6 can have various structures.

[0099] In some embodiments, the housing 6 may include a first housing 6a and a second housing 6b. The first housing 6a and the second housing 6b are fastened together to form a closed space inside the housing 6 to accommodate the battery cell pack 5. Here, "closed" refers to covering or closing, and can be either sealed or unsealed.

[0100] In some embodiments, the housing 6 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 6 forms an enclosed space to accommodate the battery cell pack 5. As an example, the frame may include multiple side beams.

[0101] As an example, the first housing 6a may include a frame and a base plate, and the second housing 6b may include a top cover.

[0102] In some embodiments, the housing 6 may be part of the vehicle's chassis structure. For example, a portion of the housing 6 may be at least a portion of the vehicle's floor, or a portion of the housing 6 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0103] In some embodiments, the battery device 2 may be an energy storage device.

[0104] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0105] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0106] Figure 3 Schematic diagram of a battery device provided for some embodiments of this application; Figure 4 An exploded schematic diagram of a single battery cell in a battery device provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell for a battery device provided in some embodiments of this application; Figure 6 This is a cross-sectional schematic diagram of the electrode assembly of a battery device provided in some embodiments of this application.

[0107] Reference Figures 3 to 6This application provides a battery device 2, which includes a housing 6 and a plurality of battery cell groups 5. The housing 6 has a receiving cavity 6c, and the plurality of battery cell groups 5 are disposed in the receiving cavity 6c. The plurality of battery cell groups 5 are arranged along a first direction Y, and each battery cell group 5 includes a plurality of battery cells 7 arranged along a second direction X. The second direction X is perpendicular to the first direction Y and parallel to the thickness direction of the battery cells 7.

[0108] The receiving cavity 6c is the main space of the housing 6 for arranging the battery cells 7. In some examples, the receiving cavity 6c is a single, interconnected space; in other examples, the receiving cavity 6c may include multiple sub-cavities spaced apart from each other, each sub-cavity accommodating a portion of the battery cells 7; for example, the housing 6 includes at least one beam that can separate adjacent sub-cavities.

[0109] The dimension L1 of the receiving cavity 6c along the second direction X is greater than the dimension W1 of the receiving cavity 6c along the first direction Y. For example, the second direction X may be parallel to the length direction of the receiving cavity 6c, the first direction Y may be parallel to the width direction of the receiving cavity 6c, the dimension of the receiving cavity 6c along the second direction X may be the length of the receiving cavity 6c, and the dimension of the receiving cavity 6c along the first direction Y may be the width of the receiving cavity 6c.

[0110] In some examples, the receiving cavity 6c includes a plurality of sub-cavities arranged along a first direction Y, and W1 may be equal to the sum of the dimensions of the plurality of sub-cavities in the first direction Y; in other examples, the receiving cavity 6c includes a plurality of sub-cavities arranged along a second direction X, and L1 may be equal to the sum of the dimensions of the plurality of sub-cavities in the second direction X.

[0111] As an example, the battery cells 7 in the battery device 2 are of the same type and specifications.

[0112] As an example, multiple battery cell groups 5 have the same number of battery cells 7.

[0113] As an example, multiple battery cells 7 can be arranged in an array along the first direction Y and the second direction X. The receiving cavity 6c has a larger size in the second direction X, while the battery cells 7 have a smaller size in the second direction X. Therefore, embodiments of this application can arrange more battery cells 7 in the second direction X.

[0114] In some embodiments, the battery cell 7 includes a housing 20 and at least one electrode assembly 10 disposed within the housing 20.

[0115] In some embodiments, the outer casing 20 may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc.

[0116] In some embodiments, the housing 20 can be a sealed structure or a non-sealed structure. As an example, when the housing 20 is a non-sealed structure, it serves to protect the electrode assembly 10, and a sealing bag is included between the housing 20 and the electrode assembly 10. The sealing bag is used to encapsulate the electrode assembly 10 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the housing 20 is a sealed structure, it is used to encapsulate the electrode assembly 10 and the electrolyte, among other components.

[0117] In some embodiments, the casing 20 of the battery cell 7 is a square casing.

[0118] In some embodiments, the housing 20 includes a housing 20a and an end cap 20b, the housing 20a having an opening, and the end cap 20b being connected to the housing 20a and covering the opening.

[0119] The housing 20a is a component used to fit the end cap 20b to form the internal cavity of the battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0120] The housing 20a and the end cap 20b can be separate components. For example, an opening can be provided on the housing 20a, and the end cap 20b can be used to close the opening to form an internal cavity for the battery cell 7.

[0121] The housing 20a can be of various shapes and sizes, such as a cuboid. Specifically, the shape of the housing 20a can be determined according to the specific shape and size of the electrode assembly 10. The housing 20a can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0122] The shape of the end cap 20b can be adapted to the shape of the housing 20a to fit the housing 20a. The material of the end cap 20b can be the same as or different from the material of the housing 20a. Optionally, the end cap 20b can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap 20b is not easily deformed when subjected to compression and impact, so that the battery cell 7 can have higher structural strength and improve reliability.

[0123] The end cap 20b is connected to the housing 20a by welding, bonding, snap-fitting or other means.

[0124] The housing 20a may be open at one end or open at both ends. In some examples, the housing 20a may be a structure with an opening on one side, and one end cap 20b is provided to cover the housing 20a. In other examples, the housing 20a may also be a structure with openings on both sides, and two end caps 20b are provided, with the two end caps 20b respectively covering the two openings of the housing 20a.

[0125] In some embodiments, electrode assembly 10 is a component in the battery cell 7 where an electrochemical reaction occurs. Electrode assembly 10 may be one or more.

[0126] In some examples, the electrode assembly 10 of the battery cell 7 is one; in other examples, the electrode assembly 10 of the battery cell 7 is multiple, and the multiple electrode assemblies 10 may be arranged in the housing 20 along the second direction X.

[0127] For example, in the battery device 2, all battery cells 7 have the same number of electrode assemblies 10.

[0128] In some embodiments, the electrode assembly 10 includes a positive electrode 11 and a negative electrode 12. During the charging and discharging of the battery cell 7, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode 11 and the negative electrode 12.

[0129] In some embodiments, the positive electrode 11 may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0130] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0131] As an example, the positive electrode current collector can be made of carbon, metal foil, or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, titanium, silver-treated aluminum, or stainless steel can be used. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0132] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. Other conventional materials that can be used as positive electrode active material layers in batteries may also be used as positive electrode active materials. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.92 Co 0.03 Mn 0.05 O2, LiNi 0.95 Co 0.02 Mn 0.03 O2 or LiNi 0.96 Co 0.02 Mn 0.02 O2, lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0133] In some embodiments, the negative electrode 12 may include a negative electrode current collector 121 and a negative electrode active material layer 122 disposed on at least one surface of the negative electrode current collector 121.

[0134] As an example, the negative electrode current collector 121 can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0135] As an example, the negative electrode active material layer 122 includes a negative electrode active material. The negative electrode active material may be a negative electrode active material known in the art for use in battery cells 7. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of this application may also use other conventional materials that can be used as battery negative electrode active materials. These negative electrode active materials may be used alone or in combination.

[0136] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector 121 can be made of copper.

[0137] In some embodiments, the electrode assembly 10 further includes an isolator 13 disposed between the positive electrode 11 and the negative electrode 12. The isolator 13 can reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0138] In some embodiments, the separator 13 includes a separator membrane. The separator membrane in this application can be any known porous structure separator membrane with good chemical and mechanical stability.

[0139] As an example, the main material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator 13 may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0140] In some embodiments, the separator 13 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode 11 and the negative electrode 12, and serves to both transport ions and isolate the positive and negative electrodes.

[0141] In some embodiments, the battery cell 7 further includes an electrolyte housed within the casing 20. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid.

[0142] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0143] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0144] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0145] In some embodiments, the gel electrolyte comprises a polymer-based backbone network coupled with an ionic liquid-lithium salt.

[0146] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0147] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0148] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0149] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0150] In some embodiments, the electrode assembly 10 is a wound structure and includes a straight region 10a and two bent regions 10b connected to the straight region 10a. The two bent regions 10b are respectively disposed on both sides of the straight region 10a along the first direction Y.

[0151] The bending region 10b is the area in the electrode assembly 10 that has a bending structure. In the bending region 10b, the positive electrode 11, the negative electrode 12, and the separator 13 are all bent. For example, the portion of the positive electrode 11 located in the bending region 10b is generally bent into an arc shape, and the portion of the negative electrode 12 located in the bending region 10b is generally bent into an arc shape.

[0152] The flat region 10a is a region of the electrode assembly 10 with a flat structure. The portions of the positive electrode 11 and the negative electrode 12 located in the flat region 10a are substantially flat. Exemplarily, the surface of each layer of positive electrode 11 and the surface of each layer of negative electrode 12 located in the flat region 10a are substantially planar.

[0153] In some embodiments, the battery device 2 includes a housing 6 and a plurality of battery cell groups 5. The housing 6 has a receiving cavity 6c, in which the plurality of battery cell groups 5 are disposed. The plurality of battery cell groups 5 are arranged along a first direction Y, and each battery cell group 5 includes a plurality of battery cells 7 arranged along a second direction X, the second direction X being perpendicular to the first direction Y and parallel to the thickness direction of the battery cells 7. The dimension L1 of the receiving cavity 6c along the second direction X is greater than the dimension W1 of the receiving cavity 6c along the first direction Y. The battery cell 7 includes a housing 20 and at least one electrode assembly 10 disposed within the housing 20, the at least one electrode assembly 10 being arranged along the second direction X. The electrode assembly 10 has a wound structure and includes a flat region 10a and two bent regions 10b connected to the flat region 10a, the two bent regions 10b being respectively disposed on both sides of the flat region 10a along the first direction Y. The ratio of the total dimension W2 of the bending region 10b arranged along the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is 2.4%-10.2%.

[0154] As an example, the number of battery cell packs 5 is m, correspondingly, the number of battery cells 7 arranged in the first direction Y is m, and the number of electrode assemblies 10 arranged in the first direction Y is m. Each electrode assembly 10 includes two bending regions 10b, so W2 is the sum of the dimensions of 2×m bending regions 10b in the first direction Y. For example, the dimension of the bending region 10b along the first direction Y is W. 20 Therefore, W2 can be equal to 2×m×W 20 .

[0155] As an example, W 20 It can be measured as follows:

[0156] Discharge the individual battery cells to the lower cutoff voltage (e.g., 2.0V);

[0157] Using CT (Computed Tomography) technology, X-rays are used to obtain cross-sectional images of a single battery cell. The cross-section is parallel to the first and second directions, and it shows bending and straight areas.

[0158] Based on the image, a virtual straight line is defined. This virtual straight line is parallel to the first direction and passes through the innermost isolator of the bend area. The intersection of the virtual straight line and the innermost isolator of the bend area is the first intersection point, and the intersection of the virtual straight line and the outermost isolator of the bend area is the second intersection point. The distance between the first intersection point and the second intersection point can be W. 20 .

[0159] As an example, W2 / W1 can be 2.4%, 2.5%, 2.8%, 3.0%, 3.2%, 3.4%, 3.5%, 3.8%, 4.0%, 4.2%, 4.4%, 4.5%, 4.8%, 5.0%, 5.2%, 5.4%, 5.5%, 5.8%, 6.0%, 6.2%, 6.4%, 6.5%, 6.8%, 7.0%, 7.2%, 7.4%, 7.5%, 7.8%, 8.0%, 8.2%, 8.4%, 8.5%, 8.8%, 9.0%, 9.2%, 9.4%, 9.5%, 9.8%, 10.0%, or 10.2%.

[0160] Compared to the curved area 10b, the straight area 10a has a higher space utilization rate.

[0161] The voltage of the battery device 2 is usually set according to requirements. When the voltage of the battery device 2 is fixed, the total number of battery cells 7 contained therein is also determined.

[0162] The bending region 10b is roughly semi-circular, and its dimension along the first direction Y is approximately half the thickness of the straight region 10a. The thickness of the straight region 10a is its dimension along the second direction X. The dimension of the battery cell 7 along the second direction X is related to the number of electrode assemblies 10 and also to the dimension of the straight region 10a along the second direction X. When the dimension of the battery cell 7 along the second direction X is constant, the number of electrode assemblies 10 is negatively correlated with the thickness of the straight region 10a, that is, the number of electrode assemblies 10 is negatively correlated with the dimension of the bending region 10b along the first direction Y. Correspondingly, when the number of electrode assemblies 10 is constant, the dimension of the battery cell 7 along the second direction X is positively correlated with the thickness of the straight region 10a, that is, the dimension of the bending region 10b along the first direction Y is positively correlated with the dimension of the battery cell 7 along the second direction X.

[0163] For example, for a battery device 2 with defined specifications, L1 and W1 are constant, and the voltage of the battery cell 7 in the battery device 2 is constant. The number of battery cells 7 in the battery cell group 5 can be n, and when the voltage of the battery device 2 is constant, the value of m×n is constant. Given a constant number k of electrode assemblies 10 in the battery cell 7, the larger m is, the smaller n is, the larger the thickness of each battery cell 7, and the larger the dimension W of the bending region 10b along the first direction Y. 20 The larger m is, the larger n is, the smaller the thickness of each battery cell 7 is, and the dimension W of the bending region 10b along the first direction Y is... 20 The smaller the value, the better. In summary, given a fixed number k of electrode components 10 in the battery cell 7, m and W... 20 A positive correlation exists: the larger m is, the larger W2 is, the larger the space occupied by the bending region 10b in the first direction Y, the smaller the space occupied by the straight region 10a in the first direction Y, and the lower the space utilization rate of the battery device 2 in the first direction Y; the smaller m is, the smaller W2 is, the smaller the space occupied by the bending region 10b in the first direction Y, the larger the space occupied by the straight region 10a in the first direction Y, and the higher the space utilization rate of the battery device 2 in the first direction Y.

[0164] The larger m is and the smaller n is, the fewer the number of casings 20 in the battery cell pack 5, the smaller the space occupied by the casings 20 in the second direction X, the larger the space occupied by the electrode assembly 10 in the second direction X, and the higher the space utilization rate of the battery device 2 in the second direction X; the smaller m is and the larger n is, the larger the space occupied by the casings 20 in the second direction X, the smaller the space occupied by the electrode assembly 10 in the second direction X, and the lower the space utilization rate of the battery device 2 in the second direction X.

[0165] When m and n are constant, k and W 20 Negative correlation; the larger k is, the smaller the size of the flat region 10a along the first direction Y, W 20The smaller W2 is, the smaller the space occupied by the bending region 10b in the first direction Y, and the larger the space occupied by the straight region 10a in the first direction Y, resulting in higher space utilization of the battery device 2 in the first direction Y. However, W 20 The smaller the curvature, the smaller the maximum curvature of each layer of electrode in the bending region 10b. During the cycle charging and discharging of the battery cell, the electrode in the bending region 10b is at higher risk of breaking due to stress concentration.

[0166] In this embodiment, setting W2 / W1 to less than or equal to 10.2% reduces the space occupied by the bending region 10b in the first direction Y, thereby improving the space utilization rate of the battery device 2 in the first direction Y. In this embodiment, setting W2 / W1 to greater than or equal to 2.4% reduces the space occupied by the casing 20 in the second direction X, improving the space utilization rate of the battery device 2 in the second direction X, and also reduces the likelihood of the electrode in the bending region breaking due to stress concentration. In summary, setting W2 / W1 to 2.4%-10.2% in this embodiment can, to a certain extent, balance the space utilization rate of the battery device 2 in the first direction Y and the second direction X, thereby improving the volumetric energy density of the battery device 2 and enhancing its reliability.

[0167] In some embodiments, the receiving cavity 6c is a rectangular cavity.

[0168] In some embodiments, the receiving cavity 6c is not partitioned.

[0169] In some embodiments, a portion of the spacer 13 is formed in the bending region 10b, and another portion of the spacer 13 is formed in the straight region 10a.

[0170] In some embodiments, the ratio of the total dimension W2 of the bending region 10b arranged along the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is 3%-7%. Embodiments of this application can further balance the space utilization rate of the battery device 2 in the first direction Y and the space utilization rate in the second direction X, thereby improving the volumetric energy density of the battery device 2.

[0171] In some embodiments, the number m of battery cell packs 5 is 3 or 4. Optionally, the number of battery cell packs 5 is 4.

[0172] In this embodiment, the battery cells 7 are arranged in 3 or 4 columns, which can take into account both the space utilization rate of the battery device 2 in the first direction Y and the space utilization rate in the second direction X, thereby improving the volumetric energy density of the battery device 2.

[0173] In some embodiments, the number of electrode assemblies 10 in the battery cell 7 is 1, 2, or 4. Optionally, the number of electrode assemblies 10 in the battery cell 7 is 2.

[0174] In some embodiments, the ratio of the dimension L1 of the receiving cavity 6c along the second direction X to the dimension L2 of the battery cell 7 along the second direction X is 30-84.

[0175] As an example, L1 / L2 can be 30, 32, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58, 60, 62, 65, 68, 70, 72, 75, 78, 80, 82 or 84.

[0176] The value of L1 / L2 is positively correlated with the number of battery cells 7 in the battery cell pack 5. In this embodiment, setting L1 / L2 to less than or equal to 84 can reduce the number of casings 20 in the battery cell pack 5 and improve the space utilization of the battery device 2 in the second direction X. In this embodiment, setting L1 / L2 to greater than or equal to 30 can reduce the thickness of the battery cells 7, save the space occupied by the bending area 10b, and improve the space utilization of the battery device 2 in the first direction Y.

[0177] In this embodiment, L1 / L2 is set to 30-84, which can, to a certain extent, balance the space utilization rate of the battery device 2 in the first direction Y and the space utilization rate in the second direction X, thereby improving the volumetric energy density of the battery device 2.

[0178] In some embodiments, L1 / L2 can be 52-70.

[0179] In some embodiments, the battery cell group 5 further includes functional components (not shown) disposed between adjacent battery cells 7 in the second direction X.

[0180] In some examples, the functional component may include a thermal insulation element that can reduce heat transfer between battery cells 7; in the event of thermal runaway of a battery cell 7, the thermal insulation element can slow down the spread of heat.

[0181] In other examples, the functional component may include a buffer. During charging, the battery cell 7 expands in the second direction X. The buffer can be compressed and deformed to provide space for the expansion of the battery cell 7, reduce the pressure on the battery cell 7, and reduce the risk of electrode cracking and short circuit.

[0182] Since the functional components will occupy a certain space in the second direction X, n is less than L1 / L2.

[0183] In some embodiments, n can be 25-80. For example, n can be 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58, 60, 62, 65, 68, 70, 72, 75, 78 or 80.

[0184] In some embodiments, the total number of battery cells 7 in the battery device 2 is 144-300. Optionally, the total number of battery cells 7 is 144, 156, 168, 180, 192, 204, 228, 240, 252, 264, 276, 288 or 300.

[0185] In some embodiments, the system voltage of the battery device 2 may be 400V, 600V, 800V, 1000V or 1200V.

[0186] In some embodiments, the dimension W1 of the receiving cavity 6c along the first direction Y is 900mm-1400mm.

[0187] As an example, W1 can be 900mm, 950mm, 1000mm, 1100mm, 1200mm, 1300mm or 1400mm.

[0188] For example, the battery device 2 can be applied to electric vehicles. By setting W1 to 900mm-1400mm, the battery device 2 can be adapted to electric vehicles of different sizes.

[0189] In some embodiments, the dimension L1 of the receiving cavity 6c along the second direction X is 1300mm-2100mm.

[0190] As an example, L1 can be 1300mm, 1400mm, 1500mm, 1600mm, 1700mm, 1800mm, 1900mm, 2000mm or 2100mm.

[0191] Setting L1 to 1300mm-2100mm allows the battery device 2 to be adapted to electric vehicles of different sizes.

[0192] In some embodiments, the dimension W3 of the battery cell 7 along the first direction Y is 250mm-450mm. As an example, W3 is 250mm, 280mm, 300mm, 320mm, 350mm, 380mm, 400mm, 420mm or 450mm. Optionally, W3 is 300mm-350mm.

[0193] In some embodiments, the dimension L2 of the battery cell 7 along the second direction X is 20mm-40mm. As an example, L2 is 20mm, 21mm, 23mm, 25mm, 27mm, 29mm, 30mm, 31mm, 33mm, 35mm, 37mm, 39mm or 40mm. Optionally, L2 is 25mm-35mm.

[0194] In some embodiments, the dimension H1 of the battery cell 7 along the third direction Z is 90mm-130mm. As an example, H1 is 90mm, 93mm, 95mm, 97mm, 100mm, 103mm, 105mm, 107mm, 110mm, 113mm, 115mm, 117mm, 120mm, 123mm, 125mm, 127mm or 130mm.

[0195] As an example, the dimension of the housing 20 along the third direction Z is taken as the dimension H1 of the battery cell 7 along the third direction Z; when measuring H1, other components protruding from the housing 20, such as electrode terminals 40, are not considered.

[0196] In some embodiments, adjacent battery cell groups 5 are spaced apart in the first direction Y. During the assembly of the battery device 2, it is necessary to place the battery cell groups 5 into the receiving cavity 6c; by spaced apart, space can be provided for the clamps that hold the battery cell groups 5.

[0197] In some embodiments, an adhesive is provided between adjacent battery cell groups 5, which can bond adjacent battery cell groups 5 together to improve the structural strength of the battery device 2.

[0198] In some embodiments, the positive electrode active material may include lithium phosphate; the negative electrode active material may include graphite.

[0199] In some embodiments, the charging rate of the battery cell 7 may be 1C, 2C, 3C or 4C.

[0200] In some embodiments, the housing 20 includes two first walls 21 disposed opposite to each other along a first direction Y and two second walls 22 disposed opposite to each other along a second direction X, wherein each first wall 21 is connected to the two second walls 22.

[0201] The thickness of the first wall 21 and the thickness of the second wall 22 can be the same or different.

[0202] The first wall 21 and the second wall 22 can be integrally formed. Alternatively, the first wall 21 and the second wall 22 can also be formed independently and connected by welding or other means.

[0203] In some examples, housing 20a includes a first wall 21 and a second wall 22. In other examples, of the two first walls 21 and the two second walls 22, at least one wall is an end cap 20b, and the remaining walls form part of housing 20a.

[0204] In some embodiments, the first wall 21 is perpendicular to the second wall 22.

[0205] In some embodiments, the first wall 21 is a flat plate structure, and the second wall 22 is a flat plate structure.

[0206] In some embodiments, the housing 20a is integrally formed and includes two first walls 21 and two second walls 22.

[0207] In some embodiments, the thickness of the second wall 22 is less than the thickness of the first wall 21.

[0208] Compared to the number of battery cell packs 5, the number of battery cells 7 in battery cell packs 5 is greater. Correspondingly, in the battery device 2, the number of second walls 22 arranged along the second direction X is greater than the number of first walls 21 arranged along the first direction Y. This embodiment uses second walls 22 with a smaller thickness, which can reduce the space occupied by all the second walls 22 of the battery cell pack 5 in the second direction X, improve space utilization, and increase the energy density of the battery device 2.

[0209] When the electrode assembly 10 expands, the thinner second wall 22 can undergo slight elastic deformation to release expansion stress, thereby reducing the risk of the casing 20 cracking. Compared to the second wall 22, the first wall 21 can have a larger thickness, thereby improving the impact resistance of the sides of the battery cell 7 and reducing the risk of the casing 20 breaking in the event of a collision, drop, or other accidental event to the battery device 2. Since the number of battery cell groups 5 is relatively small, using a thicker first wall 21 has a relatively small impact on the energy density of the battery device 2.

[0210] In some embodiments, the thickness t1 of the first wall 21 is 0.5mm-1.2mm. As an example, the thickness of the first wall 21 is 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm or 1.2mm.

[0211] In this embodiment, the thickness of the first wall 21 is set to be greater than or equal to 0.5 mm to improve the strength of the first wall 21 and reduce the risk of breakage. In another embodiment, the thickness of the first wall 21 is set to be less than or equal to 1.2 mm, which reduces the space occupied by the first wall 21 in the first direction Y, improves the space utilization of the battery device 2 in the first direction Y, and increases the volumetric energy density of the battery device 2.

[0212] In some embodiments, the thickness t2 of the second wall 22 is 0.3mm-0.8mm. As an example, the thickness of the second wall 22 is 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm or 0.8mm.

[0213] In this embodiment, the thickness of the second wall 22 is set to be greater than or equal to 0.3 mm to improve the strength of the second wall 22 and reduce the risk of breakage. In another embodiment, the thickness of the second wall 22 is set to be less than or equal to 0.8 mm, which reduces the space occupied by the second wall 22 in the second direction X, improves the space utilization of the battery device 2 in the second direction X, and increases the volumetric energy density of the battery device 2.

[0214] In some embodiments, the ratio of the total dimension W4 of the first wall 21 arranged along the first direction Y in the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is 0.2%-1%.

[0215] As an example, W4 can be equal to 2×m×t1.

[0216] As an example, W4 / W1 can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%.

[0217] In this embodiment, W4 / W1 is set to be greater than or equal to 0.2% to improve the strength of the first wall 21 and reduce the risk of the first wall 21 breaking. In this embodiment, W4 / W1 is set to be less than or equal to 1% to reduce the space occupied by the first wall 21 in the first direction Y, improve the space utilization rate of the battery device 2 in the first direction Y, and improve the volumetric energy density of the battery device 2.

[0218] In some embodiments, the ratio of the total dimension L3 of the second wall 22 of the battery cell pack 5 in the second direction X to the dimension L1 of the receiving cavity 6c in the second direction X is 1.0%-4.5%.

[0219] As an example, L3 can be equal to 2×n×t2.

[0220] As an example, L3 / L1 can be 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, or 4.5%.

[0221] In this embodiment, setting L3 / L1 to be greater than or equal to 1.0% can improve the strength of the second wall 22 and reduce the risk of its breakage. Setting L3 / L1 to less than or equal to 4.5% can reduce the space occupied by the second wall 22 in the second direction X. With a fixed thickness of the second wall 22, setting L3 / L1 to 1.0%-4.5% can, to a certain extent, balance the space utilization rate of the battery device 2 in the first direction Y and the second direction X, thereby improving the volumetric energy density of the battery device 2.

[0222] In some embodiments, L3 / L1 can be 1%-3%.

[0223] In some embodiments, the ratio of the total dimension L4 of all electrode assemblies 10 of the battery cell pack 5 along the second direction X to the dimension L1 of the receiving cavity 6c along the second direction X is greater than or equal to 77%.

[0224] As an example, the dimension of the flat region 10a of the electrode assembly 10 along the second direction X is L5, the number of electrode assemblies 10 of the battery cell 7 is k, and L4 can be equal to n×k×L5.

[0225] As an example, L4 / L1 can be 77%, 78%, 79%, 80%, 81%, 83%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%.

[0226] The embodiments of this application can enable the battery device 2 to have a higher space utilization rate in the second direction X, thereby improving the energy density of the battery device 2.

[0227] In some embodiments, L4 / L1 is greater than or equal to 89%.

[0228] In some embodiments, the ratio of the total dimension W5 of the electrode assembly 10 arranged along the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is greater than or equal to 90%.

[0229] As an example, the dimension of the straight region 10a along the first direction Y is W6, and W5 can be equal to m × (2 × W). 20 +W6).

[0230] As an example, W5 / W1 can be 90%, 91%, 92%, 93%, 94%, 95%, or 96%.

[0231] The embodiments of this application can enable the battery device 2 to have a higher space utilization rate in the first direction Y, thereby improving the energy density of the battery device 2.

[0232] In some embodiments, the housing 20 further includes a third wall 23 and a fourth wall 24 disposed opposite each other along a third direction Z, the third direction Z being perpendicular to the second direction X and the first direction Y.

[0233] The third wall 23 is connected to the two first walls 21 at both ends along the first direction Y, and the third wall 23 is connected to the two second walls 22 at both ends along the second direction X.

[0234] The two ends of the fourth wall 24 along the first direction Y are respectively connected to the two first walls 21, and the two ends of the fourth wall 24 along the second direction X are respectively connected to the two second walls 22.

[0235] In some embodiments, one of the third wall 23 and the fourth wall 24 is an end cap 20b, and the other is the bottom wall of the housing 20a. In other embodiments, both the third wall 23 and the fourth wall 24 are end caps 20b, and the housing 20a is open at both ends along the third direction Z.

[0236] In some embodiments, the thickness of the end cap 20b is 1.2mm-2.5mm. As an example, the thickness of the end cap 20b is 1.2mm, 1.3mm, 1.5mm, 1.7mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm or 2.5mm.

[0237] In some embodiments, one of the third wall 23 and the fourth wall 24 is the bottom wall of the housing 20a. The thickness of the bottom wall is 0.6 mm to 1.5 mm. As an example, the thickness of the bottom wall is 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm.

[0238] In some embodiments, when the battery device 2 is in use, the third wall 23 is located above the fourth wall 24; correspondingly, the third direction Z is parallel to the vertical direction.

[0239] In some embodiments, a pressure relief mechanism 30 is provided on the housing 20. The pressure relief mechanism 30 is used to release the internal gas of the battery cell 7.

[0240] As an example, the internal pressure or temperature of the battery cell 7 is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell 7 reaches the predetermined threshold, the pressure relief mechanism 30 is activated or a weak structure provided in the pressure relief mechanism 30 is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode 11, negative electrode 12, electrolyte, and separator 13 in the battery cell 7.

[0241] As an example, the pressure relief mechanism 30 can be integrally formed with one wall of the housing 20.

[0242] As an example, the pressure relief mechanism 30 can also be separately configured and connected to the housing 20.

[0243] The term "actuation" as used in this application refers to the pressure relief mechanism 30 being activated or undergoing a certain state, thereby releasing the internal pressure and temperature of the battery cell 7. The actions of the pressure relief mechanism 30 may include, but are not limited to: movement of components within the pressure relief mechanism 30 to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the pressure relief mechanism 30, etc. When the pressure relief mechanism 30 is actuated, the high-temperature, high-pressure substances inside the battery cell 7 are discharged outwards from the actuated portion as exhaust materials. This method enables pressure and temperature relief of the battery cell 7 under controllable pressure or temperature conditions, thereby preventing potentially more serious accidents.

[0244] In some embodiments, the pressure relief mechanism 30 is disposed on at least one of the second wall 22, the third wall 23, and the fourth wall 24.

[0245] In some examples, the pressure relief mechanism 30 is located on the fourth wall 24; in the event of thermal runaway of the battery cell 7, the battery cell 7 releases pressure downwards. In other examples, the pressure relief mechanism 30 is located on the third wall 23; in the event of thermal runaway of the battery cell 7, the battery cell 7 releases pressure upwards.

[0246] In some embodiments, the electrode assembly 10 is provided with tabs 10c, which can conduct current from the electrode assembly 10. There are multiple tabs 10c, some of which are positive tabs and others are negative tabs. Exemplarily, the portion of the positive current collector not covered by the positive active material layer forms a positive tab, and the portion of the negative current collector not covered by the negative active material layer forms a negative tab.

[0247] In some embodiments, both the positive and negative tabs extend from the flat region 10a. Exemplarily, the positive and negative tabs may extend from the same end of the flat region 10a along the third direction Z, or they may extend from opposite ends of the flat region 10a along the third direction Z, respectively.

[0248] In some embodiments, the battery cell 7 further includes an electrode terminal 40, which is disposed on the housing 20 and connected to the tab 10c.

[0249] The electrode terminal 40 serves to output or input electrical energy of the battery cell 7. One end of the electrode terminal 40 is used to be electrically connected to the tab 10c of the electrode assembly 10, and the other end is used to be connected to the busbar component to realize the input or output of electrical energy of the battery cell 7.

[0250] For example, the electrode terminal 40 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. Of course, in some embodiments, the electrode terminal 40 can also be a composite material, that is, the electrode terminal 40 is formed by connecting two different metal materials, such as by hot pressing or cold pressing.

[0251] In some embodiments, there are multiple electrode terminals 40, each including a positive terminal and a negative terminal, with the positive terminal electrically connected to a positive tab and the negative terminal electrically connected to a negative tab.

[0252] In some embodiments, the positive and negative terminals are disposed on the same wall of the housing 20. Exemplarily, the positive and negative terminals may be disposed on a third wall 23.

[0253] In other embodiments, the positive and negative terminals are respectively disposed on two walls of the housing 20. For example, one of the positive and negative terminals is disposed on the third wall 23, and the other is disposed on the fourth wall 24.

[0254] Figure 7 An exploded schematic diagram of a single battery cell of a battery device provided in other embodiments of this application; Figure 8 A cross-sectional schematic diagram of a battery cell for a battery device provided in other embodiments of this application; Figure 9 for Figure 8 Enlarged view of the area within the circle.

[0255] Reference Figures 7 to 9 In some embodiments, the housing 20 includes a third wall 23 disposed on one side of the electrode assembly 10 along a third direction Z, which is perpendicular to the second direction X and the first direction Y.

[0256] The third wall 23 can be either the end cap 20b or a wall of the housing 20a.

[0257] As an example, the thickness direction of the third wall 23 is parallel to the third direction Z.

[0258] In some embodiments, the battery cell 7 further includes an electrode terminal 40 and a fixing member 50. The electrode terminal 40 is disposed on the third wall 23 and electrically connected to the electrode assembly 10. The fixing member 50 is disposed on the periphery of the electrode terminal 40 and includes a base 51 and a limiting portion 52. The base 51 is connected to the third wall 23, and the limiting portion 52 is connected to the base 51 and extends in a direction close to the electrode terminal 40. The limiting portion 52 is configured to restrict the electrode terminal 40 from moving in the third direction (Z-direction) away from the electrode assembly 10.

[0259] The fastener 50 is secured to the third wall 23, and serves to fix the electrode terminal 40 to the third wall 23. The fastener 50 and the third wall 23 can be an integral structure or separate structures. For example, the fastener 50 and the third wall 23 are separate structures, and the fastener 50 is welded to the third wall 23. Of course, in other examples, the fastener 50 can also be bolted, snap-fitted, or glued to the third wall 23.

[0260] The fixing member 50 is disposed on the periphery of the electrode terminal 40, that is, the fixing member 50 is a structure disposed on the outer periphery of the electrode terminal 40. The fixing member 50 can be a ring structure disposed around the electrode terminal 40, or a discontinuous structure disposed around the electrode terminal 40, or an arc-shaped structure extending along the circumference of the electrode terminal 40.

[0261] The base 51 of the fixing member 50 is the part of the fixing member 50 that is connected to the third wall 23, while the limiting part 52 of the fixing part is the part of the fixing member 50 that restricts the electrode terminal 40 from moving away from the electrode assembly 10 along the third direction Z.

[0262] The structure of the limiting part 52 of the fastener 50 can be various.

[0263] In some examples, a portion of the electrode terminal 40 is located between the limiting portion 52 and the third wall 23 in the third direction Z, such that the limiting portion 52 and the third wall 23 are configured to clamp the electrode terminal 40, thereby restricting the electrode terminal 40 from moving away from the electrode assembly 10 in the third direction Z.

[0264] In other examples, the limiting part 52 and the electrode terminal 40 may not overlap in the third direction Z, and the limiting part 52 may indirectly press the electrode terminal 40 against the third wall 23 through other components (such as the first insulating member described later).

[0265] The limiting part 52 is connected to the base 51 and extends in a direction close to the electrode terminal 40. That is, the limiting part 52 is a structure that is connected to the inner peripheral side of the base 51 and extends in a direction perpendicular to the third direction Z.

[0266] In this embodiment, the fixing member 50 is disposed on the periphery of the electrode terminal 40, which can restrict the movement of the electrode terminal 40 from the outer periphery; the limiting part 52 and the third wall 23 can cooperate to clamp the electrode terminal 40 to restrict the movement of the electrode terminal 40 in the third direction Z. By providing the fixing member 50 to fix the electrode terminal 40 to the third wall 23, this embodiment simplifies the structure of the battery cell 7.

[0267] Furthermore, by using the fixing member 50 to fix the electrode terminal 40, the size requirements for the battery terminal can be reduced. Therefore, the electrode terminal 40 of this embodiment is suitable for battery cells 7 with a relatively small thickness, for example, battery cells 7 with a thickness of 20mm-40mm.

[0268] In some embodiments, the battery cell 7 further includes a first insulating member 60, at least a portion of which is disposed between the electrode terminal 40 and the limiting portion 52. The first insulating member 60 can function as an insulating isolation between the limiting portion 52 of the fixing member 50 and the electrode terminal 40, thereby achieving insulating isolation between the electrode terminal 40 and the limiting portion 52 of the fixing member 50.

[0269] For example, the material of the first insulating element 60 can be various, such as rubber, silicone or plastic.

[0270] In some embodiments, a portion of the first insulating member 60 abuts against the limiting portion 52 and the electrode terminal 40 in the third direction Z.

[0271] In some embodiments, on the third direction Z, the fastener 50 is located on the side of the third wall 23 away from the electrode assembly 10. In this embodiment, the fastener 50 is positioned on the outer side of the third wall 23, which helps to reduce the space occupied by the fastener 50 within the housing 20 and improves the utilization rate of the internal space of the battery cell 7.

[0272] In some embodiments, a terminal hole 23a is provided on the third wall 23, the terminal hole 23a penetrates the third wall 23 along the third direction Z, and the electrode terminal 40 covers the terminal hole 23a along the third direction Z.

[0273] In some embodiments, the electrode terminal 40 is inserted into the terminal hole 23a along the third direction Z, such that a portion of the electrode terminal 40 is located within the terminal hole 23a, so that the electrode terminal 40 can be connected to the electrode assembly 10 located inside the housing 20, and also to the busbar located outside the housing 20, so as to realize the input or output of electrical energy of the battery cell 7.

[0274] In some embodiments, the electrode terminal 40 may be directly connected to the tab 10c of the electrode assembly 10, such as by welding or abutting, or it may be indirectly connected to the tab 10c of the electrode assembly 10 through other components. Similarly, the connection structure between the electrode terminal 40 and the busbar component may also be varied, such as by welding, abutting, or snap-fitting.

[0275] In some embodiments, the battery cell 7 may further include an adapter 70 disposed within the housing 20. The adapter 70 connects the electrode terminal 40 and the tab 10c of the electrode assembly 10 to achieve an electrical connection between the electrode assembly 10 and the electrode terminal 40.

[0276] In some embodiments, the thickness t3 of the limiting portion 52 is less than the thickness t4 of the base portion 51.

[0277] For example, the thickness direction of the limiting portion 52 and the thickness direction of the base portion 51 are both parallel to the third direction Z.

[0278] Compared to the limiting portion 52, the base portion 51 can have a larger thickness, which is beneficial to improving the connection quality and strength between the base portion 51 and the third wall 23. The limiting portion 52 is used to limit the electrode terminal 40 in the third direction Z. It does not need to be directly fixed to the electrode terminal 40. Therefore, compared to the base portion 51, the limiting portion 52 can have a smaller thickness. By reducing the thickness of the limiting portion 52, the space between the limiting portion 52 and the electrode terminal 40 for accommodating the first insulating member 60 can be increased. This allows for an increase in the thickness of the portion of the first insulating member 60 disposed between the limiting portion 52 and the electrode terminal 40, increasing the creepage distance between the limiting portion 52 and the electrode terminal 40. This helps reduce the short-circuit risk of the battery cell 7 during use, thereby improving the reliability of the battery cell 7.

[0279] In some embodiments, along the third direction Z, a portion of the electrode terminal 40 is located between the limiting portion 52 and the third wall 23.

[0280] A portion of the electrode terminal 40 extends between the limiting portion 52 and the third wall 23, such that the limiting portion 52 and the third wall 23 are located on opposite sides of the portion of the electrode terminal 40 in the third direction Z, thereby causing the projection of the limiting portion 52 in the third direction Z to overlap with the projection of the electrode terminal 40, and causing the projection of the third wall 23 in the third direction Z to overlap with the projection of the electrode terminal 40.

[0281] In this embodiment, the portion of the limiting part 52 and the portion of the third wall 23 are located on both sides of the portion of the electrode terminal 40 in the third direction Z, thereby improving the effect of the limiting part 52 and the third wall 23 in clamping and assembling the electrode terminal 40, and improving the stability and reliability of the electrode terminal 40.

[0282] In some embodiments, along the third direction Z, the surface of the limiting portion 52 facing the third wall 23 is further away from the third wall 23 than the surface of the base 51 facing the third wall 23.

[0283] For example, the fastener 50 has a stepped structure on the side facing the third wall 23 in the third direction Z, such that the fastener 50 has a receiving groove for accommodating the first insulating member 60 on the side facing the third wall 23 in the third direction Z.

[0284] In this embodiment, by setting the surface of the limiting portion 52 facing the third wall 23 to be further away from the third wall 23 than the surface of the base 51 facing the third wall 23, the portion of the electrode terminal 40 located between the limiting portion 52 and the third wall 23 can share a portion of the space with the fixing member 50 in the third direction Z. This satisfies the creepage distance between the electrode terminal 40 and the limiting portion 52 and the connection reliability between the base 51 and the third wall 23, while effectively saving the space shared by the fixing member 50 and the electrode terminal 40 in the third direction Z, thereby improving the energy density of the battery cell 7.

[0285] In some embodiments, the surface of the limiting portion 52 that is away from the third wall 23 is further away from the third wall 23 than the surface of the base 51 that is away from the third wall 23.

[0286] The limiting part 52 protrudes from the base 51 on the side away from the third wall 23 in the third direction Z, so that there is a height difference between the limiting part 52 and the base 51 in the third direction Z, and the limiting part 52 is farther away from the third wall 23 than the base 51.

[0287] In some embodiments, the fastener 50 further includes a connecting portion 53, which connects the base portion 51 and the limiting portion 52.

[0288] The structure of the connecting portion 53 can be varied. In some examples, the connecting portion 53 is a bent structure connecting the base 51 and the limiting portion 52, with the limiting portion 52 and the base 51 respectively connected to both ends of the connecting portion 53. In other examples, the connecting portion 53 includes two sections: a curved section and a straight section connected to each other. The curved section is connected to the base 51, and the straight section is connected to the limiting portion 52, with the straight section and the limiting portion 52 being parallel to each other.

[0289] In this embodiment, by providing a connecting portion 53 between the base 51 and the limiting portion 52, it is beneficial to reduce the connection difficulty between the base 51 and the limiting portion 52 and improve the connection stability between the base 51 and the limiting portion 52. On the other hand, while ensuring that the limiting portion 52 presses the electrode terminal 40 and meets the connection quality between the base 51 and the third wall 23, it is not necessary to increase the thickness of the base 51 in the third direction Z, which is beneficial to reduce the manufacturing cost of the fastener 50 and can reduce the weight of the fastener 50.

[0290] In some embodiments, the limiting portion 52 and the base portion 51 are spaced apart along the third direction Z, which helps to reduce the assembly difficulty of the electrode terminal 40 and the molding difficulty of the connecting portion 53.

[0291] In some embodiments, along a direction perpendicular to the third direction Z, the base 51 extends from the connecting portion 53 toward the direction away from the electrode terminal 40, and the limiting portion 52 extends from the connecting portion 53 toward the direction close to the electrode terminal 40.

[0292] The base 51 extends from the connecting portion 53 in a direction away from the electrode terminal 40. That is, the base 51 extends radially away from the electrode terminal 40 from one end connected to the connecting portion 53. The limiting portion 52 extends from the connecting portion 53 in a direction closer to the electrode terminal 40. That is, the limiting portion 52 extends radially closer to the electrode terminal 40 from one end connected to the connecting portion 53. The base 51 and the limiting portion 52 can be parallel to each other, and they can extend in opposite directions radially from the electrode terminal 40. It should be noted that the radial direction of the electrode terminal 40 is the direction in which the center of the electrode terminal 40 points to the outer edge of the electrode terminal 40, or the outer edge of the electrode terminal 40 points to the center of the electrode terminal 40, within a plane perpendicular to the third direction Z.

[0293] The cross-section of the fastener 50 is Z-shaped, which optimizes the structure of the fastener 50 and reduces the difficulty of connecting the fastener 50 to the third wall 23. It also reduces the interference between the base 51 and the electrode terminal 40 and reduces the space occupied by the base 51 between the third wall 23 and the limiting part 52. This facilitates the clamping and assembly of the electrode terminal 40 by the limiting part 52 and the third wall 23, and optimizes the space occupied by the fastener 50 and the electrode terminal 40 in the third direction Z.

[0294] In some embodiments, the orthographic projections of the connecting portion 53 and the electrode terminal 40 do not overlap in the same plane perpendicular to the third direction Z. That is, the connecting portion 53 and the electrode terminal 40 are arranged at intervals in the radial direction of the electrode terminal 40, such that the connecting portion 53 and the electrode terminal 40 do not cover each other in the third direction Z.

[0295] By setting the connection portion 53 and the electrode terminal 40 to a structure in which their projections in the third direction Z do not overlap, the interference between the connection portion 53 and the electrode terminal 40 can be reduced, and the creepage distance between the connection portion 53 and the electrode terminal 40 can be increased, which helps to reduce the risk of short circuit between the connection portion 53 and the electrode terminal 40.

[0296] In some embodiments, the electrode terminal 40 includes a body portion 41 and an assembly portion 42. The body portion 41 is electrically connected to the electrode assembly 10, and the assembly portion 42 protrudes from the outer peripheral surface of the body portion 41. A portion of the assembly portion 42 is located between the limiting portion 52 and the third wall 23 in the third direction Z.

[0297] The mounting portion 42 protrudes from the outer peripheral surface of the body portion 41. That is, the mounting portion 42 of the electrode terminal 40 is a structure that is connected to the outer peripheral surface of the body portion 41 and extends radially along the electrode terminal 40, so that the mounting portion 42 extends between the limiting portion 52 and the third wall 23.

[0298] By providing the mounting portion 42, a portion of the electrode terminal 40 can extend between the third wall 23 and the limiting portion 52, thereby improving the stability of the electrode terminal 40.

[0299] In some embodiments, a portion of the first insulating member 60 is located between the limiting portion 52 and the outer peripheral surface of the body portion 41.

[0300] For example, a portion of the first insulating member 60 is disposed radially between the limiting portion 52 and the body portion 41 of the electrode terminal 40 to insulate and isolate the limiting portion 52 and the body portion 41.

[0301] The first insulating member 60 can insulate and isolate the limiting part 52 and the main body part 41, thereby reducing the risk of short circuit.

[0302] In some embodiments, the mounting portion 42 surrounds the outer side of the body portion 41.

[0303] In some embodiments, the limiting portion 52 of the fixing member 50 is an annular structure, and the limiting portion 52 surrounds the outer side of the body portion 41, so that the limiting portion 52 defines the lead-out hole. The body portion 41 of the electrode terminal 40 passes through the lead-out hole along the third direction Z and protrudes from the side of the limiting portion 52 away from the third wall 23. Correspondingly, a portion of the first insulating member 60 is accommodated between the inner peripheral surface of the limiting portion 52 and the outer peripheral surface of the body portion 41.

[0304] In some embodiments, the body portion 41 extends along the third direction Z into the terminal hole 23a of the third wall 23, and the end of the body portion 41 near the electrode assembly 10 is connected to the adapter 70 to be electrically connected to the electrode assembly 10 through the adapter 70, and the end of the body portion 41 away from the electrode assembly 10 is used to be connected to the busbar component.

[0305] In some embodiments, the limiting portion 52 is embedded in the first insulating member 60. Exemplarily, the outer periphery of the first insulating member 60 is provided with a receiving groove, and the limiting portion 52 is received in the receiving groove.

[0306] In some embodiments, a first insulating member 60 separates the retainer 50 from the electrode terminal 40 in the radial direction. Exemplarily, a portion of the first insulating member 60 is located between the connecting portion 53 and the body portion 41 in the radial direction of the electrode terminal 40.

[0307] In some embodiments, the battery cell 7 further includes a second insulating member 61; at least a portion of the second insulating member 61 is disposed between the third wall 23 and the electrode terminal 40 along the third direction Z.

[0308] The second insulating element 61 can provide insulation and isolation between the third wall 23 and the electrode terminal 40, which helps to reduce the risk of short circuit between the electrode terminal 40 and the third wall 23.

[0309] In some embodiments, a second insulating member 61 is disposed around the terminal hole 23a, and the second insulating member 61 is also configured to seal the gap between the third wall 23 and the electrode terminal 40.

[0310] In some embodiments, the battery cell 7 may further include a third insulating member 62, which surrounds the electrode terminal 40. The third insulating member 62 may be disposed between the second insulating member 61 and the first insulating member 60 to fill the gap between the first insulating member 60 and the second insulating member 61, thereby increasing the creepage distance between the electrode terminal 40 and the fixing member 50 and the creepage distance between the electrode terminal 40 and the third wall 23, and reducing the risk of short circuit.

[0311] By providing a third insulating element 62, the structure of the first insulating element 60 and the second insulating element 61 can be simplified.

[0312] In some embodiments, the elastic modulus of the third insulating member 62 is less than that of the first insulating member 60. The third insulating member 62 is more easily deformable to fit the shape of the gap between the first insulating member 60 and the second insulating member 61. Compared to the third insulating member 62, the first insulating member 60 can have higher strength to limit the movement of the electrode terminal 40 relative to the third wall 23 and improve the stability of the electrode terminal 40.

[0313] In some embodiments, the battery cell 7 may further include a fourth insulating member 63 along the third direction Z. The fourth insulating member 63 is disposed on the side of the third wall 23 facing the electrode assembly 10, and a portion of the fourth insulating member 63 is located between the adapter 70 and the third wall 23 to insulate and isolate the adapter 70 and the third wall 23.

[0314] For example, the fourth insulating element 63 may be made of rubber, silicone or plastic, etc.

[0315] Figure 10 This is a partial cross-sectional schematic diagram of the fixing member of the battery cell of the battery device provided in some other embodiments of this application.

[0316] Reference Figure 9 and Figure 10In some embodiments, the fixing member 50 has a thinning groove 54 on the side facing the third wall 23 in the third direction Z, the limiting part 52 includes the bottom surface of the thinning groove 54, and the connecting part 53 includes the side surface of the thinning groove 54. A portion of the first insulating member 60 is disposed in the thinning groove 54.

[0317] By setting the thinning groove 54, more space can be provided for the first insulating element 60, thereby increasing the creepage distance and reducing the risk of insulation failure.

[0318] In some embodiments, the connecting portion 53 is provided with a curved section 531 and a straight section 532 connected to each other. The curved section 531 is connected to the base portion 51, and the straight section 532 extends from the curved section 531 toward the electrode terminal 40 in a direction perpendicular to the third direction Z. The limiting portion 52 is connected to the end of the straight section 532 facing the electrode terminal 40.

[0319] The force exerted by the limiting part 52 on the electrode terminal 40 is a structure that acts on the straight section 532, which helps to improve the overall structural strength of the fixing member 50 and enhances the effect of the limiting part 52 on pressing the electrode terminal 40.

[0320] In some embodiments, the thinning groove 54 is a structure jointly defined by the limiting portion 52 on the surface of the third wall 23 in the third direction Z and the straight section 532 on the side of the electrode terminal 40 in the radial direction of the electrode terminal 40.

[0321] Figure 11 A partial cross-sectional schematic diagram of a battery cell for another embodiment of the battery device provided in this application; Figure 12 for Figure 11 A partial sectional view of the fastener shown.

[0322] Reference Figure 11 and Figure 12 In some embodiments, the fastener 50 includes a first material layer 50a and a second material layer 50b connected to each other. At least a portion of the first material layer 50a is located within the base 51 and is connected to the third wall 23. At least a portion of the second material layer 50b is located within the limiting portion 52, and the hardness of the second material layer 50b is greater than the hardness of the first material layer 50a.

[0323] The connection structure between the portion of the first material layer 50a located within the base 51 and the third wall 23 can be varied, such as welding or bonding. Similarly, the connection structure between the first material layer 50a and the second material layer 50b can also be varied, such as bonding, welding, or composite bonding.

[0324] For example, the first material layer 50a and the second material layer 50b are stacked along the third direction Z. Both the first material layer 50a and the second material layer 50b are annular structures surrounding the outer side of the electrode terminal 40, and the second material layer 50b is located on the side of the first material layer 50a facing the third wall 23. Of course, in other embodiments, the second material layer 50b may also be located on the side of the first material layer 50a away from the third wall 23. Similarly, the second material layer 50b may also be a structure connected to the inner peripheral side of the first material layer 50a.

[0325] The second material layer 50b may be located only partially within the limiting portion 52, or it may be located entirely within the limiting portion 52, meaning that the second material layer 50b is only contained within the limiting portion 52. For example, the first material layer 50a and the second material layer 50b are integrally stacked in the third direction Z. Correspondingly, the base portion 51, the limiting portion 52, and the connecting portion 53 all contain the first material layer 50a and the second material layer 50b.

[0326] It should be noted that hardness is an inherent property of the material itself. Therefore, the hardness of the second material layer 50b is greater than the hardness of the first material layer 50a.

[0327] In this embodiment, the material of the first material layer 50a can be the same as or similar to the material of the third wall 23, so that the fastener 50 can be connected to the third wall 23 through the portion of the first material layer 50a located within the base 51, which helps to reduce the connection difficulty between the fastener 50 and the third wall 23. By placing at least a portion of the second material layer 50b, which has higher hardness, within the limiting portion 52, the structural strength of the limiting portion 52 can be improved, reducing the risk of breakage or deformation of the limiting portion 52, thereby improving the assembly effect of the fastener 50 with the electrode terminal 40. In the case of a limiting portion 52 with the same strength, placing at least a portion of the second material layer 50b, which has higher hardness, within the limiting portion 52 can further reduce the thickness of the limiting portion 52, which helps to further optimize the dimensions of the fastener 50 in the third direction Z.

[0328] In some embodiments, a portion of the first material layer 50a is located within the limiting portion 52, where the first material layer 50a and the second material layer 50b at least partially overlap along a third direction Z.

[0329] The limiting part 52 includes both the first material layer 50a and the second material layer 50b.

[0330] In the same plane perpendicular to the third direction Z, the orthographic projections of the first material layer 50a and the second material layer 50b located within the limiting portion 52 at least partially overlap. Exemplarily, the first material layer 50a and the second material layer 50b located within the limiting portion 52 completely overlap in the third direction Z.

[0331] In this embodiment, by overlapping the first material layer 50a and the second material layer 50b in the limiting part 52, the contact area between the first material layer 50a and the second material layer 50b in the limiting part 52 can be increased, thereby reducing the connection difficulty between the first material layer 50a and the second material layer 50b in the limiting part 52, strengthening the mutual constraint between the first material layer 50a and the second material layer 50b in the limiting part 52, and further improving the structural strength of the limiting part 52.

[0332] In some embodiments, a portion of the second material layer 50b is located within the base 51, where the first material layer 50a and the second material layer 50b at least partially overlap along a third direction Z.

[0333] The base 51 contains both a first material layer 50a and a second material layer 50b.

[0334] In the same plane perpendicular to the third direction Z, the orthographic projections of the first material layer 50a and the second material layer 50b located within the base 51 at least partially overlap. Exemplarily, the first material layer 50a and the second material layer 50b located within the base 51 completely overlap in the third direction Z.

[0335] In this embodiment, a first material layer 50a is provided within the base 51 to facilitate the connection between the base 51 and the third wall 23. A second material layer 50b is provided within the base 51 to enhance its structural strength, reducing the risk of breakage or deformation and thus improving the overall structural strength of the fastener 50. By overlapping the first material layer 50a and the second material layer 50b within the base 51, the contact area between them is increased, thereby improving the connection strength.

[0336] In some embodiments, a portion of the first material layer 50a is located within the connecting portion 53, and a portion of the second material layer 50b is located within the connecting portion 53. Along the third direction Z, at least a portion of the first material layer 50a and the second material layer 50b located within the connecting portion 53 overlap.

[0337] In some embodiments, in the same plane perpendicular to the third direction Z, the orthographic projections of the first material layer 50a and the second material layer 50b at least partially overlap. This embodiment can reduce the difficulty of connecting the first material layer 50a and the second material layer 50b, and strengthen the mutual constraint between them, which is beneficial to improving the overall structural strength of the fastener 50.

[0338] In some embodiments, the orthographic projections of the first material layer 50a and the second material layer 50b completely overlap in the same plane perpendicular to the third direction Z.

[0339] In some embodiments, along the third direction Z, the second material layer 50b is located on the side of the first material layer 50a facing the third wall 23.

[0340] For example, the first material layer 50a and the second material layer 50b are stacked along the third direction Z, and the second material layer 50b is disposed on the third wall 23 in the third direction Z.

[0341] By setting the second material layer 50b to the side of the first material layer 50a facing the third wall 23, it is beneficial to improve the structural strength of the side of the limiting part 52 facing the third wall 23, thereby facilitating the assembly of the electrode terminal 40 by the fixing member 50 and improving the structural stability of the electrode terminal 40 assembled on the third wall 23.

[0342] In some embodiments, the first material layer 50a is welded to the third wall 23 to form a welded portion 50c.

[0343] In some embodiments, the third wall 23 is provided with an assembly groove 23b on the side facing the limiting portion 52, and at least a portion of the base 51 is accommodated in the assembly groove 23b.

[0344] Terminal hole 23a is provided on the bottom surface of assembly groove 23b, and terminal hole 23a penetrates the bottom wall of assembly groove 23b to connect the inside and outside of housing 20.

[0345] The base 51 may be partially or entirely contained within the assembly groove 23b.

[0346] In some embodiments, the first material layer 50a may be welded to the sidewall of the assembly groove 23b to form a welded portion 50c.

[0347] In some embodiments, a first material layer 50a and a second material layer 50b are stacked, and along the stacking direction of the first material layer 50a and the second material layer 50b, the thickness of the first material layer 50a is greater than the thickness of the second material layer 50b.

[0348] For example, the stacking direction of the first material layer 50a and the second material layer 50b is parallel to the third direction Z.

[0349] By setting the thickness of the first material layer 50a to be greater than the thickness of the second material layer 50b, it is beneficial to increase the thickness of the area of ​​the base 51 used for interconnection with the third wall 23, thereby improving the stability and reliability of the connection between the fastener 50 and the third wall 23. By setting the thickness of the second material layer 50b to be less than the thickness of the first material layer 50a, the amount of the second material layer 50b can be reduced while ensuring that the strength of the fastener 50 meets the requirements.

[0350] In some embodiments, the melting point of the first material layer 50a is greater than or equal to 500°C and less than or equal to 1000°C. The melting point of the second material layer 50b is greater than or equal to 1050°C and less than or equal to 3500°C. The melting point of the third wall 23 is greater than or equal to 500°C and less than or equal to 1000°C.

[0351] The melting point of the first material layer 50a can be any one of 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃ or 1000℃ or any range between two of them.

[0352] The melting point of the second material layer 50b can be any one of 1050℃, 1150℃, 1250℃, 1350℃, 1450℃, 1550℃, 1650℃, 1750℃, 1850℃, 1950℃, 2050℃, 2150℃, 2250℃, 2350℃, 2450℃, 2550℃, 2650℃, 2750℃, 2850℃, 2950℃, 3050℃, 3150℃, 3250℃, 3350℃, 3450℃ or 3500℃ or a range between any two.

[0353] The melting point of the third wall 23 can be any one of 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃ or 1000℃ or any range between two of them.

[0354] The melting point of the first material layer 50a can be the same as that of the third wall 23, or the melting point of the first material layer 50a can be close to that of the third wall 23, so as to facilitate welding of the first material layer 50a and the third wall 23 and make the connection between the first material layer 50a and the third wall 23 stable. The second material layer 50b has a higher melting point, has better high-temperature resistance, and is not easily deformed by heat.

[0355] In some embodiments, the hardness of the first material layer 50a is greater than or equal to 30 kgf / mm².2 And less than or equal to 170 kgf / mm 2 The hardness of the second material layer 50b is greater than or equal to 100 kgf / mm². 2 And less than or equal to 500 kgf / mm 2 .

[0356] Optionally, the hardness of the first material layer 50a can be 30 kgf / mm. 2 40kgf / mm 2 50kgf / mm 2 60kgf / mm 2 70kgf / mm 2 80kgf / mm 2 90kgf / mm 2 100kgf / mm 2 110kgf / mm 2 120kgf / mm 2 130kgf / mm 2 140 kgf / mm 2 150kgf / mm 2 160kgf / mm 2 Or 170 kgf / mm 2 The range between any one of them or any two of them.

[0357] Optionally, the hardness of the second material layer 50b can be 100 kgf / mm². 2 120kgf / mm 2 140kgf / mm 2 160kgf / mm 2 180kgf / mm 2 200kgf / mm 2 220kgf / mm 2 240kgf / mm 2 260kgf / / mm 2 280kgf / mm 2 300kgf / mm 2 320kgf / mm 2 340kgf / mm 2 360kgf / mm 2 380kgf / mm 2 400kgf / mm 2 420kgf / mm 2 440kgf / mm 2 460kgf / mm 2 480kgf / mm2 Or 500 kgf / mm 2 The range between any one of them or any two of them.

[0358] By setting the hardness of the first material layer 50a to 30 kgf / mm 2 Up to 170 kgf / mm 2 This gives the first material layer 50a good resistance to deformation. The hardness of the second material layer 50b is set to 100 kgf / mm². 2 Up to 500 kgf / mm 2 This makes the second material layer 50b have better resistance to deformation than the first material layer 50a, and the overall resistance to deformation of the structure formed by the combination of the second material layer 50b and the first material layer 50a is better, so as to limit the electrode terminal 40 from moving away from the third wall 23.

[0359] In some embodiments, the material of the first material layer 50a is the same as the material of the third wall 23, and the first material layer 50a located in the base 51 is welded to the third wall 23.

[0360] The fact that the material of the first material layer 50a is the same as the material of the third wall 23 means that the main components of the first material layer 50a and the third wall 23 are the same. For example, if the first material layer 50a and the third wall 23 are both made of a single material, such as copper or aluminum, then the first material layer 50a and the third wall 23 are both composed of the same metallic element. If the first material layer 50a and the third wall 23 are made of an alloy or mixed material, such as aluminum alloy or steel, then the fact that the first material layer 50a and the third wall 23 are the same means that the main components of the first material layer 50a and the third wall 23 are the same. If the first material layer 50a and the third wall 23 differ only in the content of the components, then they are also made of the same material.

[0361] By setting the material of the first material layer 50a to be the same as that of the third wall 23, a structure in which the base 51 and the third wall 23 are welded with the same material is achieved. This helps to reduce the welding difficulty between the first material layer 50a and the third wall 23 in the base 51, and can reduce welding defects between the base 51 and the third wall 23, thereby improving the welding quality between the third wall 23 and the base 51 of the fastener 50.

[0362] In some embodiments, the first material layer 50a and the second material layer 50b are compositely connected. The fastener 50 may be a composite material formed by the composite connection of the first material layer 50a and the second material layer 50b, that is, the fastener 50 is formed by the composite connection of two different metal materials, such as hot pressing or cold pressing.

[0363] In some embodiments, the base metal of the first material layer 50a and the base metal of the second material layer 50b are the same.

[0364] The base metal of the first material layer 50a is the same as the base metal of the second material layer 50b, that is, both the first material layer 50a and the second material layer 50b are alloy structures. However, the main components of the materials of the first material layer 50a and the second material layer 50b are the same, while other components or contents are different.

[0365] By setting the base metal of the first material layer 50a and the base metal of the second material layer 50b to the same structure, so that the first material layer 50a and the second material layer 50b have the same main components, the connection difficulty between the first material layer 50a and the second material layer 50b can be reduced, thereby reducing the molding difficulty of the fastener 50.

[0366] In some embodiments, the material of the first material layer 50a may include aluminum or an aluminum alloy, and correspondingly, the material of the second material layer 50b may include steel, stainless steel, copper, copper alloy, titanium, or titanium alloy.

[0367] In some embodiments, the material of the first material layer 50a may include steel or stainless steel, and correspondingly, the material of the second material layer 50b may include titanium or titanium alloy.

[0368] In some embodiments, the second material layer 50b of the fastener 50 may also be a non-metallic material with high hardness. For example, the material of the second material layer 50b may also include ceramics, polymer plastics or carbon fiber reinforced composite materials.

[0369] Figure 13 A schematic diagram of the structure of a single battery cell for a battery device provided in some embodiments of this application; Figure 14 for Figure 13 The diagram shows an exploded battery cell; Figure 15 for Figure 13 A partial cross-sectional view of a single battery cell is shown. Figure 16 This is a cross-sectional schematic diagram of the negative electrode sheet of a battery cell in a battery device provided in some embodiments of this application.

[0370] Reference Figures 13 to 16In some embodiments, the housing 20 includes a third wall 23 disposed on one side of the electrode assembly 10 along a third direction Z, which is perpendicular to the second direction X and the first direction Y. The third wall 23 includes a first wall body 231 and a first protrusion 232. The first protrusion 232 protrudes from the outer surface of the first wall body 231 along the third direction Z. The side of the third wall 23 facing the electrode assembly 10 has a recess 233, which corresponds to the position of the first protrusion 232 and is recessed relative to the surface of the first wall body 231 facing the electrode assembly 10.

[0371] The electrode assembly 10 also includes a tab 10c, which extends from one end of the flat region 10a facing the third wall 23. In the same plane perpendicular to the third direction Z, the orthographic projection of the tab 10c at least partially overlaps with the orthographic projection of the recess 233.

[0372] By providing the recess 233, clearance space can be provided for the tab 10c, reducing the risk of interference between the tab 10c and the first wall body 231, and decreasing the distance between the first wall body 231 and the flat area 10a, thereby improving space utilization. By providing an outwardly protruding first protrusion, the depth of the recess 233 can be increased.

[0373] In some embodiments, the orthographic projection of the tab 10c does not overlap with the orthographic projection of the first wall body 231 in the same plane perpendicular to the third direction Z.

[0374] In some embodiments, a portion of the tab 10c is accommodated within the recess 233. The tab 10c and the first protrusion 232 may share a portion of space in the third direction Z, thereby improving space utilization and increasing the energy density of the battery cell 7.

[0375] In some embodiments, the battery cell 7 further includes an electrode terminal 40, which may be disposed on the first protrusion 232.

[0376] In some embodiments, the first protrusion 232 includes a top 2321 and a side 2322, the side 2322 being connectable to the top 2321 and the first wall body 231.

[0377] The inner surface of the top 2321 facing the flat region 10a can be the bottom surface of the recess 233. In the third direction Z, the inner surface of the first wall body 231 facing the flat region 10a is closer to the flat region 10a than the inner surface of the top 2321 facing the flat region 10a, and the outer surface of the first wall body 231 facing away from the flat region 10a is closer to the flat region 10a than the outer surface of the top 2321 facing away from the flat region 10a.

[0378] As an example, electrode terminal 40 can be located on the top 2321 or on the side 2322.

[0379] In some embodiments, the recess 233 extends through the third wall 23 along the second direction X to form a first opening 233a at both ends. The housing 20 includes two second walls 22 disposed opposite to each other along the second direction X, the two second walls 22 being connected to the third wall 23 and closing the first opening 233a of the recess 233.

[0380] In this embodiment, by providing a through-hole recess 233 along the second direction X, the size of the recess 233 along the second direction X and the internal space of the outer casing 20 can be increased. By using the second wall 22 to close the first opening 233a of the recess 233, the structure of the first wall 21 can be simplified.

[0381] In some embodiments, the recess 233 of the end cap 20b can be formed by stamping. Since the recess 233 extends through the second direction X, the ends of the first protrusion 232 near the second wall 22 do not need to be bent during stamping. This embodiment reduces the risk of cracking or other problems occurring in the first protrusion 232 during stamping.

[0382] An end cap 20b having a recess 233 extending along a second direction X is suitable for a battery cell 7 with a smaller thickness.

[0383] In some embodiments, the recess 233 forms a second opening 233b at one end away from the first wall body along the first direction Y. The second wall 22 is connected to the first protrusion 232 and closes the second opening 233b.

[0384] In some embodiments, the second wall 22 includes a second wall body 221 and a second protrusion 222 arranged along a third direction Z. The second protrusion 222 is located on the side of the second wall body 221 close to the third wall 23. The second wall body 221 is connected to the first wall body 231, and the second protrusion 222 is connected to the first protrusion 232.

[0385] In some embodiments, the first wall 21 includes two first protrusions 232 arranged along a first direction Y, and the first wall body 231 connects the two first protrusions 232. The second wall 22 includes two second protrusions 222 arranged along the first direction Y. The two second protrusions 222 of the second wall 22 are respectively connected to the two first protrusions 232 of the first wall 21.

[0386] As an example, the second protrusions 222 of the two second walls 22 close the two first openings 233a of the recess 233.

[0387] In some embodiments, the first protrusion 232, the second protrusions 222 of the two second walls 22, and the first wall 21 together form a protrusion structure on the outer surface of the housing 20.

[0388] In some embodiments, the electrode assembly 10 includes a negative electrode 12, which includes a negative electrode active material layer 122. The ratio of the dimension H2 of the negative electrode active material layer 122 along the third direction Z to the minimum dimension H3 of the housing 20 along the third direction Z is 90%-93%.

[0389] As an example, H2 / H3 can be 90%, 91%, 92%, or 93%.

[0390] As an example, H3 can be the distance in the third direction Z between the surface of the first wall body 231 away from the fourth wall 24 and the surface of the fourth wall 24 away from the first wall body 231.

[0391] In this embodiment, setting H2 / H3 to greater than or equal to 90% increases the utilization rate of the internal space of the casing 20 and improves the energy density of the battery cell 7. In this embodiment, setting H2 / H3 to less than or equal to 93% reserves installation space for other components of the battery cell 7.

[0392] In some embodiments, the housing 20 includes a third wall 23 disposed on one side of the electrode assembly 10 along a third direction Z, which is perpendicular to the second direction X and the first direction Y. The electrode assembly 10 also includes a tab 10c extending from one end of the flat region 10a facing the third wall 23. The battery cell 7 also includes an electrode terminal 40 disposed on the third wall 23, to which the tab 10c is electrically connected. In the same plane perpendicular to the third direction Z, the orthographic projection of the electrode terminal 40 at least partially overlaps with the orthographic projection of the tab 10c. The ratio of the minimum distance D between the flat region 10a and the electrode terminal 40 along the third direction Z to the dimension H1 of the housing 20 along the third direction Z is 3%-7%.

[0393] In some examples, refer to Figure 4 The third wall 23 is generally flat. H1 can be the distance in the third direction Z between the surface of the third wall 23 away from the fourth wall 24 and the surface of the fourth wall 24 away from the third wall 23. In other examples, refer to Figure 14 The third wall 23 includes the first wall body 231 and the first protrusion 232; H1 can be the distance between the top 2321 of the first protrusion 232 away from the surface of the fourth wall 24 and the surface of the fourth wall 24 away from the third wall 23 in the third direction Z.

[0394] As an example, D / H1 can be 3%, 4%, 5%, 6%, or 7%.

[0395] In this embodiment, D / H1 is set to greater than or equal to 3% to provide a larger bending space for the tab 10c, reducing the risk of the tab 10c being inserted backwards into the straight area 10a and improving reliability. In this embodiment, D / H1 is set to less than or equal to 7%, which reduces the space occupied by the tab 10c in the third direction Z, improving space utilization. In this embodiment, D / H1 is set to 3%-7%, which can, to a certain extent, balance the reliability and energy density of the battery cell 7.

[0396] Figure 17 This is an exploded schematic diagram of a battery cell of a battery device provided in some embodiments of this application.

[0397] Reference Figure 17 In some embodiments, the battery cell 7 further includes an electrode terminal 40 and an adapter 70. The electrode terminal 40 is disposed on the first wall body 231, and the adapter 70 is connected to the electrode terminal 40. At least a portion of the adapter 70 is accommodated in the recess 233 and connected to the tab 10c.

[0398] By utilizing the recess 233 to accommodate at least a portion of the adapter 70, space utilization can be improved. In the third direction Z, the electrode terminal 40 can share a portion of the space with the first protrusion 232, thereby reducing the maximum size of the battery cell 7 in the third direction Z and improving space utilization.

[0399] According to some embodiments of this application, this application also provides an electrical device including a battery device of any of the above embodiments, the battery device being used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize a battery device.

[0400] Reference Figures 3 to 6 This application provides a battery device 2, which includes a housing 6 and four battery cell groups 5. The housing 6 has a receiving cavity 6c, in which the four battery cell groups 5 are disposed. The four battery cell groups 5 are arranged along a first direction Y, and each battery cell group 5 includes a plurality of battery cells 7 arranged along a second direction X, which is perpendicular to the first direction Y and parallel to the thickness direction of the battery cells 7. The battery cells 7 are prismatic battery cells.

[0401] The dimension L1 of the receiving cavity 6c along the second direction X is greater than the dimension W1 of the receiving cavity 6c along the first direction Y. The battery cell 7 includes a housing 20 and a plurality of electrode assemblies 10 disposed within the housing 20, the plurality of electrode assemblies 10 being arranged along the second direction X. The electrode assembly 10 has a wound structure and includes a flat region 10a and two bent regions 10b connected to the flat region 10a, the two bent regions 10b being respectively disposed on both sides of the flat region 10a along the first direction Y.

[0402] The ratio of the total dimension W2 of the bending region 10b arranged along the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is 2.4%-10.2%.

[0403] The dimension W1 of the receiving cavity 6c along the first direction Y is 900mm-1400mm. The dimension L1 of the receiving cavity 6c along the second direction X is 1300mm-2100mm.

[0404] The outer casing 20 includes two first walls 21 disposed opposite each other along a first direction Y and two second walls 22 disposed opposite each other along a second direction X, with each first wall 21 connecting to the two second walls 22. The thickness of the second wall 22 is less than the thickness of the first wall 21.

[0405] The ratio of the total dimension W4 of the first wall 21 arranged along the first direction Y to the dimension W1 of the receiving cavity 6c in the first direction Y is 0.2%-1%.

[0406] Example

[0407] The following embodiments describe the contents disclosed in this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of the embodiments of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0408] Example 1

[0409] 1. Preparation of positive electrode sheet

[0410] The positive electrode includes a positive current collector and a positive active material layer disposed on both sides of the positive current collector. The positive current collector is an aluminum foil with a thickness of 15μm.

[0411] The positive electrode active material layer comprises a film layer formed by uniformly coating the positive electrode slurry (solvent being N-methylpyrrolidone NMP) onto the surface of the positive electrode current collector, followed by drying and cold pressing. The positive electrode active material layer comprises positive electrode active material (lithium iron phosphate), binder polyvinylidene fluoride (PVDF), and conductive agent acetylene black in a weight ratio of 97:2:1.

[0412] 2. Preparation of negative electrode sheet

[0413] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on both sides of the negative electrode current collector. The negative electrode current collector is a copper foil with a thickness of 6μm.

[0414] The negative electrode active material layer comprises a film layer formed by uniformly coating a negative electrode slurry (using deionized water as the solvent) onto the surface of the negative electrode current collector, followed by drying and cold pressing. The negative electrode active material layer comprises graphite, conductive agent Super-p, and binder styrene-butadiene rubber (SBR) in a weight ratio of 97:2:1.

[0415] 3. Isolation components

[0416] A 7μm polyethylene film.

[0417] 4. Preparation of electrolyte

[0418] The electrolyte consists of organic solvents, lithium salts, and additives.

[0419] The electrolyte consists of an organic solvent and a lithium salt. Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0420] 5. Preparation of battery cells

[0421] The positive electrode, separator, and negative electrode are sequentially stacked and wound to obtain an electrode assembly with a wound structure. The width of the electrode assembly (i.e., the dimension of the electrode assembly along the first direction) is 374 mm. The electrode assembly includes a straight region and two bending regions, and the width of the bending regions (i.e., the dimension W of the bending regions along the first direction) is... 20 The width of the electrode assembly is 5mm, and the total width of the two bending areas is 10mm.

[0422] Two electrode assemblies are placed in the casing and injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a single battery cell is obtained.

[0423] The thickness of the battery cell (i.e., the dimension of the battery cell along the second direction) is 23.3 mm, the width of the battery cell (i.e., the dimension of the battery cell along the first direction) is 411.8 mm, and the height of the battery cell (i.e., the dimension of the battery cell along the third direction) is 107 mm. The thickness of the first wall of the outer casing is 0.7 mm, and the thickness of the second wall is 0.5 mm.

[0424] 6. Preparation of battery devices

[0425] The 192 battery cells prepared are installed into the housing cavity of the box. The 192 battery cells are arranged in 3 columns (i.e., 3 battery cell groups), and each battery cell group includes 64 battery cells. After welding the busbar components and installing high and low voltage wiring harnesses and other components, the battery device is obtained.

[0426] The housing cavity has a width (W1) of 1240 mm, a length (W1) of 1660 mm, and a height (W1) of 135 mm. Since the battery cells are arranged in three rows, there are three electrode assemblies arranged along the first direction. The total dimension (W2) of the bending areas along the first direction is 30 mm (the total width of the six bending areas). The volume V of the housing cavity is 1.240 × 1.660 × 0.135 = 0.278 m³. 3 The total thickness of the second wall of the 64 battery cells in the battery pack is 0.5 × 2 × 64 = 64 mm.

[0427] Example 2

[0428] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Example 2 and Example 1 are shown in Table 1.

[0429] Example 3

[0430] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Example 3 and Example 1 are shown in Table 1.

[0431] Example 4

[0432] Battery cells and battery devices were prepared using a method similar to that used in Example 1. The differences between Example 4 and Example 1 are shown in Table 1.

[0433] Example 5

[0434] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Example 5 and Example 1 are shown in Table 1.

[0435] Comparative Example 1

[0436] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Comparative Example 1 and Example 1 are shown in Table 1.

[0437] Comparative Example 2

[0438] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Comparative Example 2 and Example 1 are shown in Table 1.

[0439] Comparative Example 3

[0440] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Comparative Example 3 and Example 1 are shown in Table 1.

[0441] Comparative Example 4

[0442] Battery cells and battery devices were prepared using a method similar to that of Example 1. The differences between Comparative Example 4 and Example 1 are shown in Table 1.

[0443] test

[0444] 1. Test the total capacity of the battery device.

[0445] At 25°C, the battery device is charged at a constant current of 0.33C until the individual cell voltage reaches 3.8V. Then, the individual cells are charged at a constant voltage until the current reaches 0.05C. After the battery device is allowed to stand for 30 minutes, it is discharged at a constant current of 0.33C until the individual cell voltage reaches 2.08V. The discharge capacity at this point is recorded; this is the system energy density of the battery device. The ratio of the system energy density to the volume of the housing cavity can be used as the volumetric energy density of the battery device.

[0446] 2. Battery device cycle test

[0447] At 45°C, the battery device prepared above is fully charged at 1C (i.e., the individual battery cells are charged to 3.8V), and then fully discharged at 1C (i.e., the individual battery cells are discharged to 2.08V). This constitutes one charge-discharge cycle. The battery device is subjected to 100 charge-discharge cycles.

[0448] The battery assembly was disassembled, and 10 individual battery cells were randomly selected. Using CT (Computed Tomography) technology, X-rays were used to obtain cross-sectional images of each battery cell to observe whether the electrodes (positive and negative electrodes) in the bending area were broken.

[0449] The test results of Examples 1-5 and Comparative Examples 1-4 are shown in Table 1.

[0450]

[0451] Referring to Examples 1-5 and Comparative Example 1, in this embodiment, setting W2 / W1 to be greater than or equal to 2.4% can reduce the risk of electrode breakage in the bending area. Referring to Examples 1-5 and Comparative Example 2, in this embodiment, setting W2 / W1 to be greater than or equal to 2.4% can reduce the number of second walls in the casing, save space occupied by the casing, improve the space utilization rate of the battery device in the second direction, and increase the volumetric energy density of the battery device. Referring to Examples 1-5, Comparative Example 1, and Comparative Example 2, setting W2 / W1 to be greater than or equal to 2.4% can improve space utilization to a certain extent and reduce the risk of electrode breakage, thereby balancing the energy density and reliability of the battery device to a certain extent.

[0452] Referring to Examples 1-5 and Comparative Examples 3-4, in this embodiment, setting W2 / W1 to less than or equal to 10.2% can improve the space utilization of the battery device in the first direction and increase the volumetric energy density of the battery device. Referring to Examples 4-5 and Comparative Example 3, when the thickness of the battery cell is large, increasing the number of electrode components in the battery cell can also improve the volumetric energy density to a certain extent.

[0453] Referring to Examples 1, 2, 4 and Comparative Example 4, by limiting the number of rows of battery cells, the space utilization rate of the battery device in the first direction and the space utilization rate of the battery device in the second direction can be balanced to a certain extent, thereby improving the volumetric energy density.

[0454] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0455] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended 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 they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery device, characterized in that, include: The box-shaped enclosure has a receiving cavity; Multiple battery cell groups are disposed in the receiving cavity and arranged along a first direction. Each battery cell group includes multiple battery cells arranged along a second direction, which is perpendicular to the first direction and parallel to the thickness direction of the battery cells. Wherein, the dimension of the receiving cavity along the second direction is larger than the dimension of the receiving cavity along the first direction; The battery cell includes a housing and at least one electrode assembly disposed within the housing. The at least one electrode assembly is arranged along the second direction. The electrode assembly has a wound structure and includes a straight region and two bent regions connected to the straight region. The two bent regions are respectively disposed on both sides of the straight region along the first direction. The ratio of the total dimension of the bending area arranged along the first direction to the dimension of the receiving cavity in the first direction is 2.4%-10.2%.

2. The battery device according to claim 1, characterized in that, The ratio of the total dimension of the bending area arranged along the first direction to the dimension of the receiving cavity in the first direction is 3%-7%.

3. The battery device according to claim 1, characterized in that, The number of battery cells is 3 or 4.

4. The battery device according to claim 1, characterized in that, The ratio of the dimension of the receiving cavity along the second direction to the dimension of the battery cell along the second direction is 30-84.

5. The battery device according to claim 1, characterized in that, The outer casing includes two first walls disposed opposite each other along the first direction and two second walls disposed opposite each other along the second direction, with each first wall connecting to the two second walls.

6. The battery device according to claim 5, characterized in that, The thickness of the second wall is less than the thickness of the first wall.

7. The battery device according to claim 6, characterized in that, The thickness of the second wall is 0.3mm-0.8mm, and the thickness of the first wall is 0.5mm-1.2mm.

8. The battery device according to claim 5, characterized in that, The ratio of the total dimension of the first wall arranged along the first direction to the dimension of the receiving cavity in the first direction is 0.2%-1%.

9. The battery device according to claim 5, characterized in that, The ratio of the total dimension of the second wall of the battery cell assembly in the second direction to the dimension of the receiving cavity in the second direction is 1%-4.5%.

10. The battery device according to claim 1, characterized in that, The size of the receiving cavity along the first direction is 900mm-1400mm, and the size of the receiving cavity along the second direction is 1300mm-2100mm.

11. The battery device according to claim 1, characterized in that, The ratio of the total dimension of all the electrode assemblies of the battery cell assembly along the second direction to the dimension of the receiving cavity along the second direction is greater than or equal to 77%.

12. The battery device according to claim 1, characterized in that, The ratio of the total dimension of the electrode assembly arranged along the first direction to the dimension of the receiving cavity in the first direction is greater than or equal to 90%.

13. The battery device according to any one of claims 1-12, characterized in that, The housing includes a third wall disposed on one side of the electrode assembly along a third direction, the third direction being perpendicular to the second direction and the first direction; The battery cell further includes electrode terminals, a fixing member, and a first insulating member. The electrode terminals are disposed on the third wall and electrically connected to the electrode assembly. The fixing member is disposed on the periphery of the electrode terminal. The fixing member includes a base and a limiting part. The base is connected to the third wall. The limiting part is connected to the base and extends in a direction close to the electrode terminal. The limiting part is configured to restrict the electrode terminal from moving away from the electrode assembly in the third direction. At least a portion of the first insulating member is disposed between the electrode terminal and the limiting portion.

14. The battery device according to claim 13, characterized in that, The thickness of the limiting portion is less than the thickness of the base portion.

15. The battery device according to claim 13, characterized in that, Along the third direction, a portion of the electrode terminal is located between the limiting portion and the third wall.

16. The battery device according to claim 15, characterized in that, Along the third direction, the surface of the limiting portion facing the third wall is farther away from the third wall than the surface of the base facing the third wall, and the surface of the limiting portion away from the third wall is farther away from the third wall than the surface of the base away from the third wall; The fastener also includes a connecting portion that connects the base and the limiting portion.

17. The battery device according to claim 16, characterized in that, The fastener has a thinning groove on the side facing the third wall along the third direction, the limiting part includes the bottom surface of the thinning groove, and the connecting part includes the side surface of the thinning groove; A portion of the first insulating element is disposed in the thinning groove.

18. The battery device according to claim 15, characterized in that, The electrode terminal includes a body and an assembly. The body is electrically connected to the electrode assembly. The assembly protrudes from the outer peripheral surface of the body. A portion of the assembly is located between the limiting portion and the third wall in the third direction. A portion of the first insulating member is located between the limiting portion and the outer peripheral surface of the body portion.

19. The battery device according to claim 13, characterized in that, The fastener includes a first material layer and a second material layer that are interconnected, at least a portion of the first material layer is located within the base, and the first material layer is connected to the third wall; At least a portion of the second material layer is located within the limiting portion, and the hardness of the second material layer is greater than that of the first material layer.

20. The battery device according to claim 19, characterized in that, A portion of the first material layer is located within the limiting portion, where the first material layer and the second material layer at least partially overlap along the third direction; and / or A portion of the second material layer is located within the base, where the first material layer and the second material layer at least partially overlap in the third direction.

21. The battery device according to claim 19, characterized in that, Along the third direction, the second material layer is located on the side of the first material layer facing the third wall.

22. The battery device according to claim 19, characterized in that, The first material layer and the second material layer are stacked together, and along the stacking direction of the first material layer and the second material layer, the thickness of the first material layer is greater than the thickness of the second material layer.

23. The battery device according to claim 19, characterized in that, The hardness of the first material layer is greater than or equal to 30 kgf / mm. 2 And less than or equal to 170 kgf / mm 2 ; The hardness of the second material layer is greater than or equal to 100 kgf / mm. 2 And less than or equal to 500 kgf / mm 2 .

24. The battery device according to claim 19, characterized in that, The material of the first material layer is the same as that of the third wall, and the first material layer located in the base is welded to the third wall.

25. The battery device according to any one of claims 1-12, characterized in that, The housing includes a third wall disposed on one side of the electrode assembly along a third direction, the third direction being perpendicular to the second direction and the first direction; The third wall includes a first wall body and a first protrusion. The first protrusion protrudes out of the outer surface of the first wall body in a third direction. The third wall has a recess on the side facing the electrode assembly. The recess corresponds to the position of the first protrusion and is recessed relative to the surface of the first wall body facing the electrode assembly. The electrode assembly further includes a tab extending from one end of the flat region facing the third wall; In the same plane perpendicular to the third direction, the orthographic projection of the tab at least partially overlaps with the orthographic projection of the recess.

26. The battery device according to claim 25, characterized in that, A portion of the tab is accommodated within the recess.

27. The battery device according to claim 25, characterized in that, The electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material layer; The ratio of the dimension of the negative electrode active material layer along the third direction to the minimum dimension of the outer shell along the third direction is 90%-93%.

28. The battery device according to claim 25, characterized in that, The recess extends through the third wall along the second direction to form a first opening at both ends; The outer casing includes two second walls disposed opposite each other along the second direction, the two second walls being connected to the third wall and closing the first opening of the recess.

29. The battery device according to claim 25, characterized in that, The battery cell also includes electrode terminals and an adapter, wherein the electrode terminals are disposed on the first wall body and the adapter is connected to the electrode terminals; At least a portion of the adapter is accommodated within the recess and connected to the tab.

30. The battery device according to any one of claims 1-12, characterized in that, The housing includes a third wall disposed on one side of the electrode assembly along a third direction, the third direction being perpendicular to the second direction and the first direction; The electrode assembly further includes a tab extending from one end of the flat region facing the third wall; The battery cell also includes an electrode terminal disposed on the third wall, and the tab is electrically connected to the electrode terminal; In the same plane perpendicular to the third direction, the orthographic projection of the electrode terminal at least partially overlaps with the orthographic projection of the tab; The ratio of the minimum distance between the straight area and the electrode terminal along the third direction to the dimension of the housing along the third direction is 3%-7%.

31. The battery device according to any one of claims 1-12, characterized in that, The number of electrode assemblies in the battery cell is 2 or 4.

32. An electrical appliance, characterized in that, Includes a battery device according to any one of claims 1-31, the battery device being used to provide electrical energy.

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