Battery cell, battery device, and electric device

Abstract

The present application provides a battery cell, a battery device, and an electric device. The battery cell comprises a casing and an electrode assembly. The casing comprises two first wall portions arranged opposite to each other in a first direction. The electrode assembly is accommodated in the casing, and the electrode assembly comprises a first electrode sheet, a solid electrolyte layer, and a second electrode sheet which are stacked. When the number of charge and discharge cycles of the battery cell is less than or equal to 200, at least a part of at least one first wall portion is arched in a direction away from the electrode assembly to form an arched portion, and there is a gap between an inner surface of the arched portion and the electrode assembly, so as to provide an expansion space for the electrode assembly. The arched portion is provided, and a gap is formed between an inner surface of the arched portion and the electrode assembly, so that the gap can provide an expansion space for the electrode assembly when the electrode assembly expands, thereby reducing the expansion force exerted by the electrode assembly on the casing, reducing the risk of damage to the battery cell under the action of the expansion force, and improving the reliability of the battery cell.

Description

Battery cells, battery packs and electrical devices Cross-references to related applications

[0001] This application claims priority to Chinese Patent Application No. 202422667575.0, filed on November 1, 2024, entitled “Battery Cell, Battery Device and Power Consumption Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell, battery device, and power supply device. Background Technology

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0004] Battery devices are widely used in portable electronic devices, electric vehicles, power tools, drones, energy storage devices, and other fields. Besides considering the performance of individual battery cells, their reliability is also a crucial issue. Therefore, improving the reliability of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

[0005] This application provides a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell.

[0006] In a first aspect, embodiments of this application provide a battery cell, including a housing and an electrode assembly. The housing includes two first walls disposed opposite to each other along a first direction. The electrode assembly is housed within the housing and includes a first electrode, a solid electrolyte layer, and a second electrode. The first and second electrodes have opposite polarities. The solid electrolyte layer is disposed between the first and second electrodes. At least a portion of the first electrode, at least a portion of the solid electrolyte layer, and at least a portion of the second electrode are stacked along the first direction. Wherein, when the battery cell has fewer than or equal to 200 electrical cycles, at least a portion of at least one of the first walls arches out in a direction away from the electrode assembly to form an arched portion, and the inner surface of the arched portion has a gap with the electrode assembly to provide expansion space for the electrode assembly.

[0007] In the above technical solution, since at least a portion of the first electrode, at least a portion of the solid electrolyte layer, and at least a portion of the second electrode are stacked along the first direction, the electrode assembly is prone to expand along the first direction during charge-discharge cycles. By providing an arched portion, and having a gap between the inner surface of the arched portion and the electrode assembly, the gap can provide expansion space for the electrode assembly when it expands, reducing the expansion force of the electrode assembly pressing against the outer casing, reducing the risk of damage to the battery cell under the expansion force, and improving the reliability of the battery cell.

[0008] In some embodiments, the battery cell further includes electrode terminals, and the electrode terminals are disposed at at least one end of the housing along the second direction. The first cross-section of the arched portion is arc-shaped, and the first cross-section is parallel to the first direction and the second direction; and / or, the second cross-section of the arched portion is arc-shaped, and the second cross-section is parallel to the first direction and perpendicular to the second direction.

[0009] In this embodiment, by setting the first cross-section of the arched portion to be arc-shaped, on the one hand, it is beneficial to process the arched portion and reduce the processing difficulty of the arched portion; on the other hand, the arc-shaped first cross-section can reduce the bending area of ​​the arched portion and reduce the risk of the arched portion losing strength due to bending.

[0010] In some embodiments, the orthographic projection of the electrode assembly lies within the orthographic projection of the inner surface of the arched portion in a projection plane perpendicular to the first direction. This allows the expanded area of ​​the electrode assembly to be covered by the arched portion when it expands along the first direction, enabling the electrode assembly to expand within the gap between the inner surface of the arched portion and the electrode assembly. This reduces the risk of the first wall expanding outwards due to the electrode assembly expanding and contacting it, and also reduces the risk of excessive expansion force within the casing damaging the battery cell, thereby improving the reliability of the battery cell.

[0011] In some embodiments, when the number of electrical cycles of a battery cell is greater than or equal to 200, the contact area between the electrode assembly and the inner surface of the arch is S1, and the area of ​​the surface of the electrode assembly facing the arch is S2, where 0.6 ≤ S1 / S2 ≤ 1. As the number of electrical cycles of the battery cell increases, the electrode assembly gradually expands outward to compress the outer casing. When S1 / S2 ≥ 0.6, the electrode assembly and the arch have a larger contact area. When the arch is subjected to external compressive force, the compressive force can be transmitted to the electrode assembly through the arch, reducing the risk of the arch collapsing into the electrode assembly, thereby reducing the risk of the outer casing being damaged by external forces and improving the structural stability of the battery cell. When S1 / S2 ≤ 1, the stability of the electrode assembly within the outer casing can be improved, reducing the risk of the electrode assembly shifting its installation position. Therefore, when 0.6 ≤ S1 / S2 ≤ 1, both the structural stability of the battery cell and the risk of the electrode assembly shifting its installation position can be balanced.

[0012] In some embodiments, 0.8 ≤ S1 / S2 ≤ 1. When S1 / S2 ≥ 0.8, the electrode assembly and the arched portion can have a larger contact area, reducing the risk of the arched portion sinking into the electrode assembly, thereby further reducing the risk of the casing being damaged by external forces and improving the structural stability of the battery cell. When S1 / S2 ≤ 1, the stability of the electrode assembly within the casing can be improved, reducing the risk of the electrode assembly shifting from its mounting position. Therefore, when 0.8 ≤ S1 / S2 ≤ 1, the structural stability of the battery cell can be further improved and the risk of the electrode assembly shifting from its mounting position can be reduced.

[0013] In some embodiments, along the first direction, the arch height of the inner surface of the arch is H1, the minimum size of the electrode assembly is H2, and 0.01≤H1 / H2≤0.15. When H1 / H2≥0.01, a larger gap can be formed between the arch and the electrode assembly, thereby reducing the risk of damage to the battery cell under expansion force and improving the reliability of the battery cell. When H1 / H2≤0.15, the volume of the battery cell can be reduced without changing the size of the electrode assembly, which is beneficial to improving the volumetric energy density of the battery cell. Therefore, when 0.01≤H1 / H2≤0.15, both reducing the risk of battery cell damage and improving the volumetric energy density of the battery cell can be achieved.

[0014] In some embodiments, 0.08 ≤ H1 / H2 ≤ 0.12. When H1 / H2 ≥ 0.08, a larger gap can be formed between the arch and the electrode assembly, thereby further reducing the risk of damage to the battery cell under the action of expansion force and improving the reliability of the battery cell. When H1 / H2 ≤ 0.12, the volume of the battery cell can be reduced without changing the size of the electrode assembly, which is beneficial to further improving the volumetric energy density of the battery cell. Therefore, when 0.08 ≤ H1 / H2 ≤ 0.12, the risk of battery cell damage can be further reduced and the volumetric energy density of the battery cell can be improved.

[0015] In some embodiments, along the first direction, the minimum dimension of the housing is W1, where 25mm ≤ W1 ≤ 75mm. When W1 ≥ 25mm, on the one hand, the housing can have more space to accommodate the electrode assembly, which is beneficial to improving the volumetric energy density of the battery cell. On the other hand, since the housing can accommodate thicker electrode assemblies, the expansion of the electrode assemblies is greater, making the effect of the arched portion providing expansion space to the first wall portion more obvious. When W1 ≤ 75mm, the size of the battery cell can be reduced, reducing the risk that the battery cell is too large to be convenient to use and assemble. Therefore, when 25mm ≤ W1 ≤ 75mm, it is possible to balance improving the volumetric energy density of the battery cell and reducing the risk that the battery cell is too large to be convenient to use and assemble.

[0016] In some embodiments, the first wall portion is an arched portion. In this way, the entire first wall portion arches away from the electrode assembly, thereby increasing the volume of the gap to provide more expansion space for the electrode assembly, reducing the risk of the battery cell being damaged by internal pressure, and improving the reliability of the battery cell.

[0017] In some embodiments, both first wall portions include arched portions. This provides arched portions on both sides of the electrode assembly, allowing the battery cell more space to expand, reducing the risk of damage to the battery cell from internal pressure, and improving the reliability of the battery cell.

[0018] In some embodiments, the first wall is the wall with the largest outer surface area in the housing. This arched portion on the first wall allows for greater expansion space for the electrode assembly, reducing the risk of damage to the housing due to compressive stress.

[0019] In some embodiments, the housing includes a casing and end caps. The casing has an opening at at least one end along a first direction. Each end cap corresponds to an opening and closes the opening. At least one first wall portion serves as an end cap. By providing at least one first wall portion as an end cap, the difficulty of inserting electrode assemblies into the casing through the opening is reduced, thereby simplifying the installation of individual battery cells.

[0020] Secondly, embodiments of this application provide a battery device including a plurality of battery cells provided in any of the embodiments of the first aspect, the plurality of battery cells being arranged along a first direction. In this way, the gaps can provide expansion space for the electrode assembly, reducing the expansion force of the electrode assembly compressing adjacent battery cells, thereby reducing the risk of damage due to excessive internal stress in the battery cells.

[0021] In some embodiments, the battery device further includes an end plate, with a plurality of battery cells disposed on the same side of the end plate along a first direction. A recess is provided on the surface of the end plate facing the battery cells, and the recess is configured to engage with an arched portion of the first wall of the battery cell closest to the end plate. By providing a recess on the end plate, the engagement of the recess with the arched portion increases the contact area between the end plate and the battery cells, making the installation of the end plate and the battery cells more stable.

[0022] In some embodiments, the battery device further includes a buffer element, at least a portion of which is disposed between two adjacent battery cells. By providing a buffer element between two adjacent battery cells, the buffer element helps to increase the contact area between the two adjacent battery cells, reducing the risk of the battery cells being damaged by external pressure.

[0023] Thirdly, embodiments of this application provide an electrical device, including a battery cell provided in any one of the embodiments of the first aspect or a battery device provided in any one of the embodiments of the second aspect, wherein the battery cell is used to provide electrical energy to the electrical device.

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0025] 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.

[0026] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0027] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0028] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0029] Figure 4 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0030] Figure 5 is a cross-sectional view AA of Figure 4;

[0031] Figure 6 is a cross-sectional view of BB in Figure 4;

[0032] Figure 7 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0033] Figure 8 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0034] Figure 9 is a schematic diagram of the structure of a battery device provided in some embodiments of this application;

[0035] Figure 10 is a schematic diagram of the structure of a battery device provided in some embodiments of this application (showing the end plate);

[0036] Figure 11 is a schematic diagram of the structure of a battery device provided in some embodiments of this application (showing the buffer).

[0037] Markings: 1-Outer shell; 1a-Housing shell; 1b-End cap; 11-First wall; 111-Arch; 1111-Inner surface of arch; 12-Gap; 2-Electrode assembly; 21-First electrode; 22-Solid electrolyte layer; 23-Second electrode; 3-Electrode terminal; 10-Battery cell; 20-Casing; 201-First casing; 202-Second casing; 30-End plate; 301-Recess; 40-Buffer; 100-Battery assembly; 200-Controller; 300-Motor; 1000-Vehicle; X-First direction; Y-Second direction; Z-Third direction. Detailed Implementation

[0038] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0040] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces), unless otherwise explicitly specified.

[0043] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0044] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0045] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0046] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0047] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0048] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0049] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0050] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0051] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.85Co0.15Al0.05O2)) and their modified compounds.

[0052] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0053] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0054] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (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.).

[0055] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0056] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0057] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0058] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0059] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0060] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0061] 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.

[0062] As an example, inorganic solid electrolytes may include 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 phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0063] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0064]

[0065] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0066] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0067] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0068] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0069] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0070] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cells housed within the housing.

[0071] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0072] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0073] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0074] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0075] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0076] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0077] A battery cell can include a casing and electrode assemblies, with the electrode assemblies housed within the casing. During the battery cell's electrical cycling process, the electrode assemblies tend to expand with increasing charge-discharge cycles. The casing of the battery cell expands outward under the expansion force of the electrode assemblies. On the one hand, this can easily affect the normal operation of the battery cell itself and other adjacent components; on the other hand, the casing restricts the expansion of the electrode assemblies, easily causing damage to the battery cell. This is especially true in solid-state battery cells, where the electrode assemblies consist of a stacked first electrode, a solid electrolyte layer, and a second electrode. Typically, the first electrode, solid electrolyte layer, and second electrode are relatively thick, and the electrode assembly itself is also thick, increasing the expansion of the electrode assembly along the stacking direction of the first electrode, solid electrolyte layer, and second electrode. In such battery cells, the casing deformation is greater, and the constraint force of the casing on the electrode assemblies is greater, making the battery cell more susceptible to damage. Furthermore, the outward expansion of the casing compresses adjacent components, increasing the compressive force between the casing and other components, easily leading to battery cell damage and reducing the battery cell's reliability.

[0078] In view of this, embodiments of this application provide a battery cell, which includes a housing and an electrode assembly. The housing includes two first walls disposed opposite to each other along a first direction. The electrode assembly is housed within the housing and includes a first electrode, a solid electrolyte layer, and a second electrode. The first and second electrodes have opposite polarities, and the solid electrolyte layer is disposed between the first and second electrodes. At least a portion of the first electrode, at least a portion of the solid electrolyte layer, and at least a portion of the second electrode are stacked along the first direction. Wherein, when the battery cell has fewer than or equal to 200 electrical cycles, at least a portion of at least one of the first walls arches out in a direction away from the electrode assembly to form an arched portion, and the inner surface of the arched portion has a gap with the electrode assembly to provide expansion space for the electrode assembly.

[0079] In such a battery cell, since at least a portion of the first electrode, at least a portion of the solid electrolyte layer, and at least a portion of the second electrode are stacked along a first direction, the electrode assembly is prone to expand along the first direction during charge-discharge cycles. By providing an arched portion with a gap between the inner surface of the arched portion and the electrode assembly, the gap can provide expansion space for the electrode assembly when it expands, reducing the expansion force of the electrode assembly pressing against the outer casing, lowering the risk of the battery cell being damaged under the action of expansion force, and improving the reliability of the battery cell.

[0080] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0081] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0082] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0083] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0084] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0085] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 20 and battery cells 10, with the housing 20 used to house the battery cells 10.

[0086] The housing 20 has an enclosed space inside for accommodating the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, which are interlocked. The first housing 201 and the second housing 202 can have various shapes, such as cuboids or cylinders. The first housing 201 can be a hollow structure open on one side, and the second housing 202 can also be a hollow structure open on one side. The open side of the second housing 202 interlocks with the open side of the first housing 201, thus forming a housing 20 with an enclosed space. Alternatively, the first housing 201 can be a hollow structure open on one side, and the second housing 202 can be a plate-like structure, with the second housing 202 interlocked with the open side of the first housing 201, thus forming a housing 20 with an accommodating space.

[0087] In the battery device 100, there can be one or more battery cells 10. If there are multiple battery cells 10, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 10 are connected in both series and parallel. Alternatively, multiple battery cells 10 can be first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 20. Another option is that all battery cells 10 can be directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 10 is housed within the housing 20.

[0088] Please refer to Figure 3, which is an exploded view of a battery cell 10 provided in some embodiments of this application. The battery cell 10 may include a housing 1 and an electrode assembly 2, the electrode assembly 2 being housed within the housing 1.

[0089] In some embodiments, the housing 1 may include a housing 1a and an end cap 1b, the housing 1a having an opening and the end cap 1b closing the opening of the housing 1a. Here, "closing" refers to covering or shutting off, and can be either sealed or unsealed.

[0090] The housing 1a is a component used to house the electrode assembly 2. The housing 1a can be a hollow structure with an opening at one end, or it can be a hollow structure with openings at both opposite ends. The housing 1a can have various shapes, such as cylindrical or cuboid. The housing 1a can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The electrode assembly 2 can be partially or completely housed within the housing 1a.

[0091] The end cap 1b and the housing 1a together define a receiving space for accommodating the electrode assembly 2 and other components. The end cap 1b can be connected to the housing 1a by welding, rolling, or other methods to close the opening of the housing 1a. The shape of the end cap 1b can be adapted to the shape of the housing 1a. For example, if the housing 1a is a cuboid structure, the end cap 1b can be a rectangular plate structure adapted to the housing 1a; or if the housing 1a is a cylindrical structure, the end cap 1b can be a circular plate structure adapted to the housing 1a. The end cap 1b can also be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The end cap 1b and the housing 1a can be made of the same or different materials.

[0092] In an embodiment where the housing 1a has an opening at one end, one end cap 1b may be provided accordingly. In an embodiment where the housing 1a has openings at both opposite ends, two end caps 1b may be provided accordingly, with the two end caps 1b respectively closing the two openings of the housing 1a, and the two end caps 1b and the housing 1a together defining the receiving space.

[0093] In some embodiments, the battery cell 10 may further include electrode terminals 3, which are disposed on the housing 1 and are used for electrical connection with the tabs of the electrode assembly 2 to input or output electrical energy of the battery cell 10. The electrode terminals 3 may be disposed on the housing 1a of the housing 1 or on the end cap 1b of the housing 1. The electrode terminals 3 and the tabs may be directly connected, for example, by welding the electrode terminals 3 to the tabs. Alternatively, the electrode terminals 3 and the tabs may be indirectly connected, for example, by a current collector. The current collector may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0094] Please refer to Figures 4 and 5. Figure 4 is a structural schematic diagram of a battery cell 10 provided in some embodiments of this application; Figure 5 is a cross-sectional view AA of Figure 4. This application provides a battery cell 10, including a housing 1 and an electrode assembly 2. The housing 1 includes two first wall portions 11 disposed opposite to each other along a first direction X. The electrode assembly 2 is housed within the housing 1 and includes a first electrode 21, a solid electrolyte layer 22, and a second electrode 23. The first electrode 21 and the second electrode 23 have opposite polarities. The solid electrolyte layer 22 is disposed between the first electrode 21 and the second electrode 23. At least a portion of the first electrode 21, at least a portion of the solid electrolyte layer 22, and at least a portion of the second electrode 23 are stacked along the first direction X. Wherein, when the battery cell 10 has fewer than or equal to 200 electrical cycles, at least a portion of at least one of the first wall portions 11 arches out in a direction away from the electrode assembly 2 to form an arched portion 111, and a gap 12 exists between the inner surface 1111 of the arched portion and the electrode assembly 2 to provide expansion space for the electrode assembly 2.

[0095] The first electrode 21 can be the positive electrode, the second electrode 23 can be the negative electrode, and the first active material layer can be the positive active material; or the first electrode 21 can be the negative electrode, the second electrode 23 can be the positive electrode, and the second active material layer can be the negative active material.

[0096] The first electrode 21, the solid electrolyte layer 22, and the second electrode 23 of the electrode assembly 2 have an overlapping area in a projection plane perpendicular to the first direction X.

[0097] The solid electrolyte layer 22 may be disposed along the first direction X between at least a portion of the first electrode 21 and at least a portion of the second electrode 23; or the entire solid electrolyte layer 22 may be disposed along the first direction X between at least a portion of the first electrode 21 and at least a portion of the second electrode 23. For example, the solid electrolyte layer 22 connects the first electrode 21 and the second electrode 23.

[0098] The electrode assembly 2 can be a stacked structure or a wound structure. In an embodiment where the electrode assembly 2 is a wound structure, there can be only one first electrode 21, one solid electrolyte layer 22, and one second electrode 23. The first electrode 21, the solid electrolyte layer 22, and the second electrode 23 are stacked and then wound to form the wound electrode assembly 2. In an embodiment where the electrode assembly 2 is a stacked structure, there can be only one first electrode 21, one solid electrolyte layer 22, and one second electrode 23. The first electrode 21, the solid electrolyte layer 22, and the second electrode 23 are stacked sequentially to form the stacked electrode assembly 2. Alternatively, there can be multiple first electrodes 21, multiple solid electrolyte layers 22, and multiple second electrodes 23. Multiple first electrodes 21, multiple solid electrolyte layers 22, and multiple second electrodes 23 are stacked sequentially in the order of first electrode 21, solid electrolyte layer 22, second electrode 23, and first electrode 21 to form a multi-layer stacked electrode assembly 2.

[0099] It is possible that only one first wall portion 11 has an arched portion 111; or both first wall portions 11 may have arched portions 111. It is possible that a portion of the first wall portion 11 arches in a direction away from the electrode assembly 2 to form an arched portion 111; or all of the first wall portions 11 may arch in a direction away from the electrode assembly 2 to form an arched portion 111.

[0100] The number of electrical cycles of a battery cell 10 refers to the number of times the battery cell 10 is charged and discharged. Each charge and discharge is counted as one electrical cycle. When the number of electrical cycles of the battery cell 10 is 200 or less, there is a gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2. For example, when the number of electrical cycles of the battery cell 10 is 0, 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 or 200, there is a gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2.

[0101] The inner surface 1111 of the arched portion is the surface of the first wall portion 11 facing the electrode assembly 2. At least a portion of the arched portion 111 does not contact the electrode assembly 2 to form a gap 12. Alternatively, the arched portion 111 may not contact the electrode assembly 2 at all to form a gap 12; or a portion of the arched portion 111 may contact the electrode assembly 2, while another portion may be away from the electrode assembly 2, with the portion of the arched portion 111 away from the electrode assembly 2 forming a gap 12 between it and the electrode assembly 2.

[0102] It is understandable that the casing of the battery cell 10 has an arched portion 111 regardless of whether the number of electrical cycles of the battery cell 10 is less than, equal to or greater than 200.

[0103] In this embodiment, since at least a portion of the first electrode 21, at least a portion of the solid electrolyte layer 22, and at least a portion of the second electrode 23 are stacked along the first direction X, the electrode assembly 2 is prone to expand along the first direction X during charge-discharge cycles. By providing an arched portion 111, and having a gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2, the gap 12 provides expansion space for the electrode assembly 2 when it expands, reducing the expansion force of the electrode assembly 2 pressing against the outer casing 1, reducing the risk of damage to the battery cell 10 under the action of expansion force, and improving the reliability of the battery cell 10. When the number of electric cycles of the battery cell 10 is less than or equal to 100, the electrode assembly 2 inside the outer casing 1 is less likely to expand to completely contact the first wall portion 11, thus creating a gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2. In this way, the battery cell 10 can continue to perform electric cycle operations, reducing the risk of the electrode assembly 2 expanding to press against the first wall portion 11 and increasing the internal stress of the battery cell 10, thereby reducing the risk of damage to the battery cell 10.

[0104] In some embodiments, please refer to Figure 6, which is a BB cross-sectional view of Figure 4. The battery cell 10 also includes an electrode terminal 3, and the housing 1 is provided with the electrode terminal 3 at at least one end along the second direction Y. The first cross-section of the arched portion 111 is arc-shaped and parallel to the first direction X and the second direction Y.

[0105] The outer casing 1 may have electrode terminals 3 at both ends along the second direction Y; alternatively, the outer casing 1 may have two electrode terminals 3 at the same end along the second direction Y. The arched portion 111 may be arc-shaped, so that the first cross-section is arc-shaped. For example, the first wall portion 11 with the arched portion 111 may be formed by bending a sheet metal. The sheet metal is bent around an axis parallel to the extension direction of the electrode terminal 3, so that the bent area of ​​the first wall portion 11 is approximately arc-shaped, and the arc-shaped bent area forms the arched portion 111.

[0106] In some embodiments, please refer to FIG7, which is a schematic diagram of the structure of a battery cell 10 provided in some embodiments of this application. The battery cell 10 further includes an electrode terminal 3, and the electrode terminal 3 is provided at least one end of the housing 1 along the second direction Y. The second cross-section of the arched portion 111 is arc-shaped, and the second cross-section is parallel to the first direction X and perpendicular to the second direction Y.

[0107] For example, the first wall portion 11 with the arched portion 111 can be formed by bending a sheet metal, with the sheet metal bent around an axis parallel to the second direction Y, so that the bent area of ​​the first wall portion 11 is approximately arc-shaped, and the arc-shaped bent area forms the arched portion 111.

[0108] In some embodiments, the battery cell 10 further includes an electrode terminal 3, and the casing 1 has an electrode terminal 3 disposed at at least one end along the second direction Y. The first cross-section of the arched portion 111 is arc-shaped and parallel to the first direction X and the second direction Y. The second cross-section of the arched portion 111 is arc-shaped and parallel to the first direction X and perpendicular to the second direction Y.

[0109] Taking a prismatic battery cell 10 as an example, the two walls of the battery cell 10 along its height direction and the two walls opposite to each other along its length direction are all cuboid in shape, and all four walls have straight edges; the two walls opposite to each other along the width direction of the battery cell 10 are spherically curved walls, which are two first walls 11. The centers of the two first walls 11 protrude away from the electrode assembly 2, and the edges of the two walls are attached to the straight edges of the adjacent walls to form an arched portion 111. The width direction, length direction and height direction of the battery cell 10 are the first direction X, the second direction Y and the third direction Z, respectively. In such a battery cell 10, the first cross section and the second cross section of the arched portion 111 are both arc-shaped.

[0110] For example, the first wall portion 11 is formed by stamping sheet metal. The first wall portion 11 is placed in a hemispherical mold and stamped to form an arched portion 111 with both the first and second cross sections being arc-shaped.

[0111] In this embodiment, by setting the first cross section of the arched portion 111 to be arc-shaped, on the one hand, it is beneficial to process the arched portion 111 and reduce the processing difficulty of the arched portion 111; on the other hand, the arc-shaped first cross section can reduce the bending area of ​​the arched portion 111 and reduce the risk of the arched portion 111 losing strength due to bending.

[0112] In some embodiments, in a projection plane perpendicular to the first direction X, the orthographic projection of the electrode assembly 2 is located within the orthographic projection of the inner surface 1111 of the arch.

[0113] In a projection plane perpendicular to the first direction X, the orthographic projection area of ​​the electrode assembly 2 may be equal to the orthographic projection area of ​​the inner surface 1111 of the arched portion, and the orthographic projection of the electrode assembly 2 may completely overlap with the orthographic projection of the inner surface 1111 of the arched portion; alternatively, the orthographic projection area of ​​the electrode assembly 2 may be smaller than the orthographic projection area of ​​the inner surface 1111 of the arched portion, a portion of the orthographic projection of the inner surface 1111 of the arched portion may completely overlap with the orthographic projection of the electrode assembly 2, and the orthographic projection of another portion of the inner surface 1111 of the arched portion may be located outside the orthographic projection of the electrode assembly 2.

[0114] In this embodiment, by setting the electrode assembly 2 in a projection plane perpendicular to the first direction X, the orthographic projection of the electrode assembly 2 is located within the orthographic projection of the inner surface 1111 of the arched portion. When the electrode assembly 2 expands along the first direction X, the expansion area of ​​the electrode assembly 2 can be covered by the arched portion 111, thereby enabling the electrode assembly 2 to expand within the gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2. This reduces the risk that the first wall portion 11 will expand outward due to the expansion of the electrode assembly 2 against the first wall portion 11, and also reduces the risk that the battery cell 10 will be damaged due to excessive expansion force inside the casing 1, thus improving the reliability of the battery cell 10.

[0115] In some embodiments, when the number of electrical cycles of the battery cell 10 is greater than or equal to 200, the contact area between the electrode assembly 2 and the inner surface 1111 of the arch is S1, and the area of ​​the surface of the electrode assembly 2 facing the arch 111 is S2, where S1 ≤ S1 / S2 ≤ 1.

[0116] When the number of electrical cycles of the battery cell 10 is greater than or equal to 200, the contact area between the electrode assembly 2 and the inner surface 1111 of the arch is at least 0.6 times the area of ​​the surface of the electrode assembly 2 facing the arch 111. For example, when the number of electrical cycles of the battery cell 10 is 200, 220, 250, 270, 300, 320, 350, 370, 400, 420, 450, 470, 500, 520, 550, 570, 600, 700, 800, 900, 1000, 2000, or 3000, S1 / S2 ≥ 0.6. When the number of electrical cycles of the battery cell 10 is 200, 300, and 400, S1 / S2 can be equal to 0.6 or greater than 0.6. When the surface of the electrode assembly 2 facing the arched portion 111 is in complete contact with the inner surface 1111 of the arched portion, S1 / S2 = 1.

[0117] The electrode assembly 2 and the arched portion 111 may have only one contact to form a contact interface, the surface area occupied by the contact interface of the electrode assembly 2 being the contact area between the electrode assembly 2 and the inner surface 1111 of the arched portion; the electrode assembly 2 and the arched portion 111 may also have multiple contacts to form multiple contact interfaces, the sum of the surface areas occupied by the multiple contact interfaces being the contact area between the electrode assembly 2 and the inner surface 1111 of the arched portion.

[0118] S1 / S2 can be any point value from 0.6, 0.62, 0.65, 0.67, 0.7, 0.72, 0.75, 0.77, 0.8, 0.82, 0.85, 0.87, 0.9, 0.92, 0.95, 0.97, 1, or a range between any two.

[0119] In this embodiment, as the number of electrical cycles of the battery cell 10 increases, the electrode assembly 2 gradually expands outward to compress the outer casing 1. When S1 / S2 ≥ 0.6, the electrode assembly 2 and the arched portion 111 have a larger contact area. When the arched portion 111 is compressed by external pressure, the pressure can be transmitted to the electrode assembly 2 through the arched portion 111, reducing the risk of the arched portion 111 collapsing into the electrode assembly 2, thereby reducing the risk of the outer casing 1 being damaged by external forces and improving the structural stability of the battery cell 10. When S1 / S2 ≤ 1, the stability of the electrode assembly 2 within the outer casing 1 can be improved, reducing the risk of the electrode assembly 2 shifting its installation position. Therefore, when S1 / S2 ≤ 1, both the structural stability of the battery cell 10 and the risk of the electrode assembly 2 shifting its installation position can be balanced. When the number of electrical cycles of the battery cell 10 is greater than or equal to 200, the electrode assembly 2 of the battery cell 10 is prone to expand to contact the arched portion 111. In such a battery cell 10, the electrode assembly 2 can support the arched portion 111. When the arched portion 111 is subjected to external pressure, the force borne by the arched portion 111 can be transmitted to the electrode assembly 2, reducing the risk of partial collapse of the arched portion 111 and damage to the structure of the arched portion 111.

[0120] In some embodiments, 08 ≤ S1 / S2 ≤ 1. S1 / S2 can be a point value of any one of 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1, or a range between any two.

[0121] When S1 / S2≥0.8, the electrode assembly 2 and the arched portion 111 can have a larger contact area, reducing the risk of the arched portion 111 sinking into the electrode assembly 2, thereby further reducing the risk of the casing 1 being damaged by external forces and improving the structural stability of the battery cell 10. When S1 / S2≤1, the stability of the electrode assembly 2 within the casing 1 can be improved, reducing the risk of the electrode assembly 2 shifting its installation position. Therefore, when S1≤S1 / S2≤1, the structural stability of the battery cell 10 can be further improved and the risk of the electrode assembly 2 shifting its installation position can be reduced.

[0122] In some embodiments, please continue to refer to Figures 4-6. Along the first direction X, the arch height of the inner surface 1111 of the arch is H1, and the minimum dimension of the electrode assembly 2 is H2, 0.01≤H1 / H2≤0.15.

[0123] The inner surface 1111 of the arched portion arches away from the electrode assembly 2 to form a groove on the inner surface 1111 of the arched portion. The entire first wall portion 11 may be the arched portion 111, with the arch height of the inner surface 1111 being the dimension of the edge of the arched portion 111 and the bottom of the groove along the first direction X; alternatively, a portion of the first wall portion 11 may be the arched portion 111, and another portion may be a straight portion, with both the inner and outer surfaces of the straight portion being planes, and the arch height of the inner surface 1111 of the arched portion being the dimension of the inner surface of the straight portion and the bottom of the groove along the first direction X.

[0124] The electrode assembly 2 expands during charging and contracts during discharging. The minimum dimension of the electrode assembly 2 along the first direction X is the minimum dimension of the electrode assembly 2 along the first direction X after it has been manufactured and has been charged and discharged less than or equal to 100 times.

[0125] H1 / H2 can be any one of the following point values: 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, or any point value between the two.

[0126] When H1 / H2≥0.01, the arched portion 111 and the electrode assembly 2 can have a larger gap 12, thereby reducing the risk of damage to the battery cell 10 under the action of expansion force and improving the reliability of the battery cell 10. When H1 / H2≤0.15, the volume of the battery cell 10 can be reduced without changing the size of the electrode assembly 2, which is beneficial to improving the volumetric energy density of the battery cell 10. Therefore, when 0.01≤H1 / H2≤0.15, it is possible to balance reducing the risk of damage to the battery cell 10 and improving the volumetric energy density of the battery cell 10.

[0127] In some embodiments, 008 ≤ H1 / H2 ≤ 012.

[0128] H1 / H2 can be any of the following point values: 0.08, 0.082, 0.085, 0.087, 0.09, 0.092, 0.095, 0.097, 0.1, 012, 0.15, 0.17, 0.11, 0.112, 0115, 0.117, 012, or any value between the two.

[0129] When H1 / H2≥0.08, the arched portion 111 and the electrode assembly 2 can have a larger gap 12, thereby further reducing the risk of damage to the battery cell 10 under the action of expansion force and improving the reliability of the battery cell 10. When H1 / H2≤0.12, the volume of the battery cell 10 can be reduced without changing the size of the electrode assembly 2, which is conducive to further improving the volumetric energy density of the battery cell 10. Therefore, when 0.08≤H1 / H2≤0.12, the risk of damage to the battery cell 10 can be further reduced and the volumetric energy density of the battery cell 10 can be improved.

[0130] In some embodiments, please continue to refer to Figures 4-6. Along the first direction X, the minimum dimension of the housing 1 is W1, where 25mm ≤ W1 ≤ 75mm.

[0131] W1≥25mm allows the outer casing 1 to accommodate a larger electrode assembly 2. In the solid-state battery cell 10, the thicker electrode assembly 2 has a larger expansion space during charge and discharge cycles. Therefore, the arched portion 111 provided on the first wall portion 11 can further enhance the effect of providing expansion space for the electrode assembly 2.

[0132] The minimum distance between the outer surfaces of the two first wall portions 11 is the minimum dimension of the outer shell 1 along the first direction X.

[0133] w1 can be a point value of any one of 25mm, 27mm, 30mm, 32mm, 35mm, 37mm, 40mm, 42mm, 45mm, 47mm, 50mm, 52mm, 55mm, 57mm, 60mm, 62mm, 65mm, 67mm, 70mm, 72mm, 75mm or any combination thereof.

[0134] When W1 ≥ 25 mm, on the one hand, the outer casing 1 has more space to accommodate the electrode assembly 2, which is beneficial to improving the volumetric energy density of the battery cell 10. On the other hand, since the outer casing 1 can accommodate a thicker electrode assembly 2, the expansion of the electrode assembly 2 is greater, making the effect of the arched portion 111 providing expansion space to the first wall portion 11 more obvious. When W1 ≤ 75 mm, the size of the battery cell 10 can be reduced, reducing the risk that the battery cell 10 is too large and inconvenient to use and assemble. Therefore, when 25 mm ≤ W1 ≤ 75 mm, it is possible to balance improving the volumetric energy density of the battery cell 10 and reducing the risk that the battery cell 10 is too large and inconvenient to use and assemble.

[0135] In some embodiments, please refer to Figures 4-6. The first wall portion 11 is an arched portion 111.

[0136] Both first wall portions 11 are arched portions 111, that is, the entirety of both first wall portions 11 arches away from the electrode assembly 2.

[0137] In this embodiment, by setting the first wall portion 11 as an arched portion 111, the first wall portion 11 is arched all along the direction away from the electrode assembly 2, thereby increasing the volume of the gap 12, so as to provide more expansion space for the electrode assembly 2, reduce the risk of the battery cell 10 being damaged by internal pressure, and improve the reliability of the battery cell 10.

[0138] In some embodiments, please continue to refer to Figures 4-6. Both first wall portions 11 include arched portions 111.

[0139] It is possible that both first wall portions 11 are entirely arched portions 111; or only a portion of either of the two first wall portions 11 is an arched portion 111; or only a portion of one first wall portion 11 is an arched portion 111, while the entire other first wall portion 11 is an arched portion 111.

[0140] In this embodiment, by providing arched portions 111 for both first wall portions 11, arched portions 111 are provided on both sides of the electrode assembly 2, thereby giving the battery cell 10 more space to facilitate the expansion of the electrode assembly 2, reducing the risk of the battery cell 10 being damaged by internal pressure, and improving the reliability of the battery cell 10.

[0141] In some embodiments, the first wall portion 11 is the wall with the largest outer surface area in the outer casing 1.

[0142] In an embodiment where only one first wall portion 11 is provided with an arched portion 111, the two first wall portions 11 are the two wall portions with the largest outer surface area in the outer shell 1, wherein the outer surface area of ​​the first wall portion 11 provided with the arched portion 111 is greater than the outer surface area of ​​the first wall portion 11 without the arched portion 111.

[0143] In an embodiment where both first wall portions 11 are provided with arched portions 111, the two first wall portions 11 are the two wall portions with the largest outer surface area in the outer shell 1, and the outer surface areas of the two first wall portions 11 may be equal or unequal.

[0144] In this embodiment, by setting the first wall portion 11 to be the wall with the largest outer surface area in the outer shell 1, and setting the arch portion 111 on the first wall portion 11, the electrode assembly 2 can have a larger expansion space, reducing the risk of the outer shell 1 being damaged by extrusion pressure.

[0145] In some embodiments, please refer to FIG8, which is a schematic structural diagram of a battery cell 10 provided in some embodiments of this application. The housing 1 includes a shell 1a and an end cap 1b. The shell 1a has an opening at at least one end along a first direction X. The end cap 1b corresponds to the opening and closes the opening. At least one first wall portion 11 is an end cap 1b.

[0146] It can be that only one first wall portion 11 is an end cap 1b; or both first wall portions 11 can be end caps 1b.

[0147] By providing at least one first wall portion 11 as an end cap 1b, the difficulty of the electrode assembly 2 entering the housing 1a through the opening can be reduced, thereby reducing the installation difficulty of the battery cell 10.

[0148] Please refer to Figure 9, which is a structural schematic diagram of a battery device 100 provided in some embodiments of this application. This application provides a battery device 100, including a plurality of battery cells 10 provided in any of the above embodiments, the plurality of battery cells 10 being arranged along a first direction X.

[0149] Along the first direction X, two adjacent battery cells 10 can be directly connected, for example, by abutting each other; or they can be indirectly connected, for example, two adjacent battery cells 10 can be connected by an insulating component, which can be insulating rubber.

[0150] In this embodiment, the gap 12 can provide expansion space for the electrode assembly 2, reduce the expansion force of the electrode assembly 2 that squeezes the adjacent battery cell 10, thereby reducing the risk of damage due to excessive internal stress of the battery cell 10.

[0151] In some embodiments, please refer to FIG10, which is a schematic diagram of the structure of a battery device 100 provided in some embodiments of the present application (showing end plate 30). The battery device 100 also includes end plate 30. Along a first direction X, a plurality of battery cells 10 are disposed on the same side of end plate 30. A recess 301 is provided on the surface of end plate 30 facing the battery cells 10. The recess 301 is configured to cooperate with the arched portion 111 of the first wall portion 11 of the battery cell 10 closest to end plate 30.

[0152] The end plate 30 may be provided on only one side of multiple battery cells 10 along the first direction X; or the end plates 30 may be provided on both opposite sides of multiple battery cells 10 along the first direction X. The recess 301 may abut or adhere to the arched portion 111 of the first wall portion 11 of the battery cell 10 closest to the end plate 30.

[0153] By providing a recess 301 on the end plate 30, the recess 301 can cooperate with the arched portion 111 to increase the contact area between the end plate 30 and the battery cell 10, making the installation of the end plate 30 and the battery cell 10 more stable.

[0154] In some embodiments, please refer to FIG11, which is a schematic diagram of the structure of a battery device 100 provided in some embodiments of the present application (showing a buffer 40). The battery device 100 also includes a buffer 40, at least a portion of which is disposed between two adjacent battery cells 10.

[0155] The buffer element 40 can be entirely disposed between two adjacent battery cells 10; or only a portion of the buffer element 40 can be disposed between two adjacent battery cells 10. The buffer element 40 can be disposed between any two adjacent battery cells 10; or only a portion of two adjacent battery cells 10 can be disposed between the buffer element 40.

[0156] By setting a buffer 40 between two adjacent battery cells 10, the buffer 40 helps to increase the contact area between the two adjacent battery cells 10 and reduce the risk of the battery cells 10 being damaged by external pressure.

[0157] This application provides an electrical device, including a battery cell 10 or a battery device 100 provided in any of the above embodiments, wherein the battery cell 10 is used to provide electrical energy to the electrical device.

[0158] Please refer to Figures 4-8. This application provides a battery cell 10, including a housing 1 and an electrode assembly 2. The housing 1 includes two first walls 11 disposed opposite each other along a first direction X. The electrode assembly 2 is housed within the housing 1 and includes a first electrode 21, a solid electrolyte layer 22, and a second electrode 23. The first electrode 21 and the second electrode 23 have opposite polarities. The solid electrolyte layer 22 is disposed between the first electrode 21 and the second electrode 23. At least a portion of the first electrode 21, at least a portion of the solid electrolyte layer 22, and at least a portion of the second electrode 23 are stacked along the first direction X. At least a portion of at least one of the first walls 11 arches away from the electrode assembly 2 to form an arched portion 111. When the battery cell 10 has fewer than or equal to 100 electrical cycles, a gap 12 exists between the inner surface 1111 of the arched portion and the electrode assembly 2 to provide expansion space for the electrode assembly 2. Along the first direction X, the arch height of the inner surface 1111 of the arched portion is H1, the minimum dimension of the electrode assembly 2 is H2, 008≤H1 / H2≤012; the minimum dimension of the outer shell 1 is W1, 25mm≤W1≤75mm. The outer shell 1 includes a housing 1a and an end cap 1b; the housing 1a has an opening at one end along the first direction X; the end cap 1b closes the opening. The first wall portion 11 is the end cap 1b.

[0159] By providing an arched portion 111, and having a gap 12 between the inner surface 1111 of the arched portion and the electrode assembly 2, the gap 12 provides expansion space for the electrode assembly 2 when it expands, reducing the expansion force of the electrode assembly 2 pressing against the outer casing 1, lowering the risk of damage to the battery cell 10 under the action of expansion force, and improving the reliability of the battery cell 10. When 008≤H1 / H2≤012, the risk of damage to the battery cell 10 can be further reduced and the volumetric energy density of the battery cell 10 can be increased. When 25mm≤W1≤75mm, the volumetric energy density of the battery cell 10 can be improved while reducing the risk of inconvenience in use and assembly due to the battery cell 10 being too large. By providing at least one first wall portion 11 as an end cap 1b, the difficulty of the electrode assembly 2 entering the casing 1a through the opening can be reduced, thereby reducing the installation difficulty of the battery cell 10.

[0160] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, comprising: The housing includes two first wall portions disposed opposite to each other along a first direction; An electrode assembly is housed within the housing. The electrode assembly includes a first electrode, a solid electrolyte layer, and a second electrode. The first electrode and the second electrode have opposite polarities. The solid electrolyte layer is disposed between the first electrode and the second electrode. At least a portion of the first electrode, at least a portion of the solid electrolyte layer, and at least a portion of the second electrode are stacked along the first direction. Wherein, when the number of electrical cycles of the battery cell is less than or equal to 200, at least a portion of at least one of the first wall portions arches in a direction away from the electrode assembly to form an arched portion, and the inner surface of the arched portion has a gap with the electrode assembly to provide expansion space for the electrode assembly.

2. The battery cell as described in claim 1, wherein, The battery cell further includes electrode terminals, and the electrode terminals are provided at least one end of the housing along the second direction; The first cross-section of the arched portion is arc-shaped, and the first cross-section is parallel to the first direction and the second direction; And / or, the second cross section of the arched portion is arc-shaped, the second cross section being parallel to the first direction and perpendicular to the second direction.

3. The battery cell as described in claim 1 or 2, wherein, In a projection plane perpendicular to the first direction, the orthographic projection of the electrode assembly lies within the orthographic projection of the inner surface of the arch.

4. The battery cell according to any one of claims 1-3, wherein, When the number of electrical cycles of the battery cell is greater than or equal to 200, the contact area between the electrode assembly and the inner surface of the arch is S1, the area of ​​the surface of the electrode assembly facing the arch is S2, and 0.6≤S1 / S2≤1.

5. The battery cell as described in claim 4, wherein, 0.8≤S1 / S2≤1.

6. The battery cell according to any one of claims 1-5, wherein, Along the first direction, the arch height of the inner surface of the arched portion is H1, and the minimum size of the electrode assembly is H2, where 0.01≤H1 / H2≤0.

15.

7. The battery cell as described in claim 6, wherein, 0.08≤H1 / H2≤0.

12.

8. The battery cell according to any one of claims 1-7, wherein, Along the first direction, the minimum dimension of the outer shell is W1, where 25mm ≤ W1 ≤ 75mm.

9. The battery cell according to any one of claims 1-8, wherein, The first wall portion is the arched portion.

10. The battery cell according to any one of claims 1-9, wherein, Both of the first wall portions include the arched portion.

11. The battery cell according to any one of claims 1-10, wherein, The first wall portion is the wall with the largest outer surface area in the outer shell.

12. The battery cell according to any one of claims 1-11, wherein, The outer casing includes: The housing has an opening at at least one end along the first direction; End caps, each corresponding to one of the openings, close the openings; At least one of the first wall portions is the end cap.

13. A battery device comprising a plurality of battery cells as described in any one of claims 1-12, wherein the plurality of battery cells are arranged along the first direction.

14. The battery device of claim 13, wherein, The battery device further includes an end plate, and a plurality of battery cells are disposed on the same side of the end plate along the first direction. The surface of the end plate facing the battery cells is provided with a recess, which is configured to engage with the arched portion of the first wall of the battery cell closest to the end plate.

15. The battery device as claimed in claim 13 or 14, wherein, The battery device further includes a buffer, at least a portion of which is disposed between two adjacent battery cells.

16. An electrical device comprising a battery cell as described in any one of claims 1-12 or a battery device as described in any one of claims 13-15, wherein the battery cell is used to provide electrical energy to the electrical device.

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