Battery cell, battery apparatus, and electric device

Abstract

A battery cell (100), a battery apparatus (200), and an electric device (300). The battery cell (100) comprises: a flexible housing (10) and an electrode assembly (20), wherein the electrode assembly (20) is arranged within the flexible housing (10), the flexible housing (10) has a side surface (11) opposite to a main surface of the electrode assembly (20) and a circumferential surface (12) avoiding the main surface, and the circumferential surface (12) is circumferentially connected to the side surface (11) around the electrode assembly (20); and at least the circumferential surface (12) is provided with a pressure relief area (121).

Description

Battery cells, battery devices and electrical equipment Technical Field

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

[0002] In related technologies, the high difficulty in directional pressure relief of individual pouch battery cells hinders further improvements in the reliability of pouch battery devices. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. Therefore, one objective of this application is to provide a battery cell, battery device, and electrical equipment, wherein the battery cell has higher reliability.

[0004] This application provides a battery cell, including: a flexible shell and an electrode assembly, the electrode assembly being disposed within the flexible shell; wherein, the flexible shell has a side surface opposite to the large surface of the electrode assembly, and a circumferential surface avoiding the large surface, the circumferential surface and the side surface being circumferentially connected around the electrode assembly; at least the circumferential surface is provided with a pressure relief area.

[0005] According to the embodiments of this application, by setting a pressure relief area on the flexible shell, the battery cell can achieve directional pressure relief in the event of thermal runaway, thereby enabling the orderly discharge of high-temperature gas flow inside the battery cell, reducing damage to the insulation interface of the battery device, reducing secondary damage, and improving the reliability of the battery cell and even the battery device.

[0006] According to some embodiments of this application, the pressure relief zone includes a weak portion disposed on the circumferential surface, the weak portion being configured to rupture to relieve pressure when the pressure within the flexible housing exceeds a pressure threshold.

[0007] According to some embodiments of this application, the membrane material of the flexible shell is constructed as a stacked multilayer membrane structure, and includes at least a metal barrier layer, with weak portions formed in the metal barrier layer, or the weak portions extending through at least a portion of the metal barrier layer.

[0008] According to some embodiments of this application, the weak point is constructed as a groove that penetrates at least a portion of the metal barrier layer.

[0009] According to some embodiments of this application, the outline shape of the groove is one or more of the following: circular, elliptical, rectangular, straight, and Z-shaped.

[0010] According to some embodiments of this application, there are multiple notches, which are spaced apart on the circumferential or side surface of the flexible housing.

[0011] According to some embodiments of this application, the thickness of the film material of the flexible shell is D1, the depth of the scribe is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

[0012] According to some embodiments of this application, the membrane material of the flexible shell includes: a metal barrier layer, a first plasticized barrier layer located on the side of the metal barrier layer facing the electrode assembly, and a second plasticized barrier layer located on the side away from the electrode assembly. The metal barrier layer includes a body region and a weak region corresponding to the weak part, and the weak region is made of a different material than the body region.

[0013] According to some embodiments of this application, the membrane material of the flexible shell includes: a metal barrier layer, a first plasticized barrier layer located on the side of the metal barrier layer facing the electrode assembly, and a second plasticized barrier layer located on the side away from the electrode assembly. The metal barrier layer includes a body region and a weak region corresponding to the weak part, and the thickness of the weak region is less than the thickness of the body region.

[0014] According to some embodiments of this application, the membrane material further includes: a filling layer located between the first plasticized barrier layer and the metal barrier layer and filling the weak area; and / or a filling layer located between the second plasticized barrier layer and the metal barrier layer and used to fill the weak area.

[0015] According to some embodiments of this application, the battery cell is any one of lithium iron phosphate battery cell, ternary lithium battery cell, and solid-state battery cell.

[0016] According to some embodiments of this application, when the battery cell is a lithium iron phosphate battery cell, the ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent in the positive electrode material of the battery cell is 96:(1-3):(1-3); when the battery cell is a ternary lithium battery cell, the ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent in the positive electrode material of the battery cell is 96:(2-3):(1-2).

[0017] This application provides a battery device, including: a housing and a battery pack, wherein the battery pack is at least one, and the battery pack includes: at least one battery cell as described in the above embodiments and a casing, wherein at least one side surface of the casing has a pressure relief portion.

[0018] According to the battery device of the present application embodiment, by providing a pressure relief part on the casing that cooperates with the pressure relief area, when the battery cell experiences thermal runaway, the high-temperature gas flow discharged through the pressure relief area (weak part) can be further released outward through the pressure relief part. In order to improve the reliability of the battery device, the cooperation between the weak part and the pressure relief part enables the directional discharge of the high-temperature gas flow.

[0019] According to some embodiments of this application, the covering shell includes a first plate and a second plate located on both sides of the first plate, a pressure relief portion is formed on the first plate, and the pressure relief area is at least partially opposite to the pressure relief portion.

[0020] According to some embodiments of this application, the second plate is opposite to the side, and the projected outline area of ​​the second plate toward the side of the flexible shell is less than or equal to the area of ​​the side.

[0021] According to some embodiments of this application, the first plate is spaced apart from the side of the circumferential surface with a weak portion to define an exhaust passage.

[0022] According to some embodiments of this application, the first plate is constructed as a flat plate or an arc plate.

[0023] According to some embodiments of this application, there are multiple pressure relief sections, which are spaced apart in the length direction and / or width direction of the first plate.

[0024] According to some embodiments of this application, the shell is constructed of aluminum or stainless steel.

[0025] According to some embodiments of this application, the housing has a bottom plate, which is connected to the battery cell by an adhesive layer.

[0026] According to some embodiments of this application, the base plate includes a cold plate, and an adhesive layer is located between the cold plate and a plurality of battery cells.

[0027] According to some embodiments of this application, the adhesive layer includes: an adhesive layer body and an overflow portion, the overflow portion being located on the side of the adhesive layer body facing a plurality of battery cells and located between adjacent battery cells and / or between a battery cell and a second plate.

[0028] This application proposes an electrical device, including the battery device described in the above embodiments.

[0029] According to some embodiments of this application, the electrical equipment is a vehicle.

[0030] According to some embodiments of this application, the battery device is integrated into the vehicle chassis, and the top plate of the housing participates in defining the vehicle floor.

[0031] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0032] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0033] Figure 1 is a schematic diagram of a battery device according to an embodiment of this application;

[0034] Figure 2 is a schematic diagram of an electrical device according to an embodiment of this application;

[0035] Figure 3 is a schematic diagram of a battery cell according to an embodiment of this application (first type of notch);

[0036] Figure 4 is a top view of the individual battery cell in Figure 3;

[0037] Figure 5 is a schematic diagram of a battery cell according to an embodiment of this application (second type of notch);

[0038] Figure 6 is a top view of the individual battery cell in Figure 5;

[0039] Figure 7 is a schematic diagram of a battery cell according to an embodiment of this application (third type of notch);

[0040] Figure 8 is a top view of the individual battery cell in Figure 7;

[0041] Figure 9 is a schematic diagram of the membrane material of the flexible casing of a battery cell according to an embodiment of the present application (the groove extends to the metal barrier layer);

[0042] Figure 10 is a schematic diagram of the membrane material of the flexible shell of a battery cell according to an embodiment of the present application (the material of the main body area and the weak area are different);

[0043] Figure 11 is a schematic diagram of the membrane material of the flexible shell of a battery cell according to an embodiment of the present application (the thickness of the main body area and the weak area are different);

[0044] Figure 12 is a schematic diagram of the groove extension position according to an embodiment of this application;

[0045] Figure 13 is a schematic diagram of a battery pack according to an embodiment of this application;

[0046] Figure 14 is a schematic diagram of the battery pack and the base plate according to an embodiment of this application. Detailed Implementation

[0047] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0048] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0049] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0050] A single battery cell can be a rechargeable battery. A rechargeable battery is a battery cell that can be recharged after it has been discharged, allowing the active materials to be activated and the cell to continue to be used.

[0051] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0052] The battery device mentioned in the embodiments of this application may include one or more battery packs for providing voltage and capacity. The battery pack may include multiple individual battery cells, which are connected in series, parallel, or mixed connections via busbars.

[0053] In some embodiments, the battery pack is typically formed by arranging multiple battery cells.

[0054] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more battery packs housed within the housing.

[0055] As an example, the battery pack can be a battery module, which can be housed in the housing by fixing the battery module in the housing.

[0056] 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 battery pack. 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.

[0057] 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 battery pack.

[0058] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0059] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical equipment using battery devices.

[0060] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0061] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0062] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. A battery device 200 is installed inside the vehicle, and the battery device 200 can be located at the bottom, front, or rear of the vehicle. The battery device 200 can be used to power the vehicle; for example, the battery device 200 can serve as the vehicle's operating power source.

[0063] The vehicle may also include a controller 600 and a motor 700. The controller 600 controls the battery device 200 to supply power to the motor 700, which serves as a load, for example, for the power needs of the vehicle during starting, navigation and driving.

[0064] In some embodiments of this application, the battery device 200 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0065] Please refer to Figure 2, which is an exploded view of a battery device 200 provided in some embodiments of this application. The battery device 200 includes a housing 400 for accommodating individual battery cells 100.

[0066] The housing 400 is a component that houses the individual battery cells 100 and provides placement space for the battery pack 500. The housing 400 can adopt various structures. In some embodiments, the housing 400 may include a tray and a cover, which close together to define a placement space for accommodating the individual battery cells 100. The tray and cover can be of various shapes, such as cuboids, cylinders, etc. The tray can be a hollow structure open on one side, and the cover can also be a hollow structure open on one side, with the open side of the cover closing onto the open side of the tray, thus forming a housing 400 with placement space. Alternatively, the tray can be a hollow structure open on one side, and the cover can be a plate-like structure, with the cover closing onto the open side of the tray, thus forming a housing 400 with placement space.

[0067] As an example, the battery cell 100 can be a pouch battery cell.

[0068] In the battery device 200, there can be one or more battery cells 100. Multiple battery cells 100 are loaded into a battery pack 500 by a casing 510. One or more battery packs 500 are loaded into a housing 400. If there are multiple battery cells 100, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 100 are connected in both series and parallel. Alternatively, multiple battery cells 100 can first be connected in series, parallel, or in a mixed configuration to form a battery pack 500, and then multiple battery packs 500 can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 400.

[0069] The battery cell 100 serves as the smallest energy unit of the battery device 200. The battery cell 100 includes a flexible housing 10 and an electrode assembly 20 disposed within the flexible housing 10.

[0070] The internal environment formed by the flexible housing 10 can be used to accommodate the electrode assembly 20, electrolyte, and other components. An opening can be formed on one side of the flexible housing 10 for injecting electrolyte and for inserting the electrode assembly 20 into the housing.

[0071] Electrode terminals can be further disposed on the flexible casing 10. The electrode assembly 20 is the component in the battery cell 100 where the electrochemical reaction occurs. The flexible casing 10 may contain one or more electrode assemblies 20. The electrode assembly 20 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active material constitute the main body of the electrode assembly 20, and the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery device 200, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0072] The positive electrode sheet may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0073] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0074] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, silver-surfaced aluminum, or stainless steel can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0075] As an example, when the battery cell 100 in this embodiment is a lithium-ion battery, the positive electrode active material may include at least one of the following materials: phosphate, layered transition metal oxide, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxide and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 100. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode film layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0076] Examples of phosphates 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.

[0077] Layered transition metal oxides include those with the general formula Li a Ni b Co c M d O e A f At least one of the compounds and their modified compounds. 0.8 ≤ a ≤ 1.2, 0.3 ≤ b < 1, 0 < c < 1, 0 < d < 1, 1 ≤ e ≤ 2, 0 ≤ f ≤ 1, M includes at least one of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes at least one of N, F, S, and Cl. Optionally, 0.5 ≤ b < 1, and further optionally, 0.75 ≤ b ≤ 0.98.

[0078] Examples of layered transition metal oxides may include, but are not limited to, 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, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 LiNi 0.9 Co 0.05 Mn 0.05 O2 (also known as Ni90), 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.

[0079] When the battery cell 100 in this application embodiment is a sodium-ion battery, the positive electrode active material may include, but is not limited to, at least one of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0080] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x At least one of the materials in general formula X. p M' q (PO4) r O x Y 3-x In the given information, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, X includes at least one of H+, Li+, Na+, K+ and NH4+, M' is a transition metal cation, optionally at least one of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally at least one of F, Cl and Br.

[0081] In the embodiments of this application, the modified compounds of the above-mentioned positive electrode active materials can be doped and / or surface coated to modify the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0082] During the charging and discharging process, the battery cell 100 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 100 at different discharge states. In the examples of positive electrode active materials in this application, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery system, the molar content of Li may change after charge-discharge cycles.

[0083] In the examples of positive electrode active materials in this application, the molar content of oxygen (O) is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0084] In this embodiment, the elemental content in the positive electrode active material is defined in a way known in the art and can be detected using equipment and methods known in the art. For example, referring to EPA 6010D-2014, it can be measured by inductively coupled plasma atomic emission spectrometry (ICP-OES, instrument model: Thermo ICAP7400). First, 0.4g of the positive electrode active material is weighed and 10ml (50% concentration) of aqua regia is added. Then, it is placed on a plate at 180℃ for 30min. After digestion on the plate, the volume is adjusted to 100mL, and quantitative testing is performed using the standard curve method.

[0085] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, a positive electrode film layer may or may not be provided on the surface of the foamed metal. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0086] In some embodiments, the positive electrode film layer may optionally include a positive electrode conductive agent. This application embodiment does not particularly limit the type of positive electrode conductive agent. As an example, the positive electrode conductive agent includes at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode film layer is ≤5 wt%.

[0087] In some embodiments, the positive electrode film layer may optionally include a positive electrode binder. This application embodiment does not impose any particular limitation on the type of positive electrode binder. As an example, the positive electrode binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode film layer is ≤5 wt%.

[0088] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to it.

[0089] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material.

[0090] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0091] 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 silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, 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.).

[0092] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 100. As an example, the negative electrode active material may include at least one of the following materials: carbon materials (e.g., carbon materials include at least one of artificial graphite, natural graphite, soft carbon, and 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. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode films may also be used. These negative electrode films may be used alone or in combination of two or more.

[0093] In some embodiments, the negative electrode active material includes silicon, which may exist in the form of a silicon-based material, such as elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The introduction of silicon can increase the energy density of the battery cell 100.

[0094] In some embodiments, the mass content of silicon in the negative electrode film layer is from 1 wt% to 32 wt%, optionally from 2 wt% to 19 wt%, and further optionally from 6 wt% to 13 wt%. In the battery cell 100 system, when the mass content of silicon is within the above range, the energy density of the battery cell 100 can be improved.

[0095] In the embodiments of this application, the mass content of silicon in the negative electrode film layer has a meaning known in the art and can be detected using equipment and methods known in the art. For example, the negative electrode sheet can be immersed in a solvent such as water to separate the negative electrode active material from the negative electrode current collector, and the negative electrode active material can be obtained by filtration. The silicon content of the negative electrode active material can be obtained by using an ICAP7400 inductively coupled plasma atomic emission spectrometer from Thermo Fisher Scientific, USA, in accordance with the GB / T30902-2014 standard.

[0096] In some embodiments, the negative electrode film layer may optionally include a negative electrode conductive agent. This application embodiment does not particularly limit the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode film layer is ≤5 wt%.

[0097] In some embodiments, the negative electrode film layer may optionally include a negative electrode binder. This application embodiment does not impose any particular limitation on the type of negative electrode binder. As an example, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode film layer is ≤5%.

[0098] In some embodiments, the negative electrode film may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of other additives in the negative electrode film is ≤2 wt%.

[0099] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0100] In some embodiments, the separator includes a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0101] This application does not impose any particular restrictions on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0102] In some embodiments, the material of the separator may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0103] In some embodiments, the separator may include a porous base membrane and a coating disposed on at least one side of the porous base membrane, the coating including at least one of inorganic particles or organic particles.

[0104] Porous base membranes may include one or more of polyethylene and polypropylene.

[0105] Inorganic particles possess good heat resistance, which can improve the overall heat resistance of the separator. Within the operating voltage range of sodium-ion batteries, inorganic particles essentially do not undergo oxidation and reduction reactions with metal dendrites. In other words, inorganic particles are configured to prevent oxidation and reduction reactions with alkali metals and / or alkaline earth metals at the nominal voltage of sodium-ion batteries.

[0106] In some embodiments, the inorganic particles include one or more of boehmite γ-AlOOH, aluminum oxide Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3, and magnesium fluoride MgF2.

[0107] In some embodiments, the organic particles include at least one of polystyrene, polyethylene, polyimide, melamine resin, phenolic resin, polypropylene, polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyphenylene sulfide, polyarylamide, polyamide-imide, polyimide, copolymers of butyl acrylate and ethyl methacrylate, and mixtures thereof.

[0108] In some embodiments, the battery cell 100 further includes an electrolyte.

[0109] During the charging and discharging process of a single battery cell, active ions repeatedly insert and extract between the positive and negative electrode plates, while the electrolyte acts as a conductor for these active ions. This application does not impose any particular restrictions on the type of electrolyte; it can be selected according to actual needs.

[0110] Electrolytes consist of electrolyte salts and solvents. The types of electrolyte salts and solvents are not specifically limited and can be selected according to actual needs.

[0111] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0112] For example, the additives include at least one of the following: cyclic carbonate compounds containing unsaturated bonds, sulfate compounds, sulfite compounds, sulfonyl lactone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphonitrile compounds, acid anhydrides, cyclic acid anhydride compounds, phosphite compounds, phosphate compounds, borate esters, and carboxylic acid esters.

[0113] In related technologies, the electrode assembly 20 of the battery cell 100 is disposed inside the flexible shell 10. The flexible shell 10 itself is constructed of high-temperature resistant material. In the event of thermal runaway, the damage to the flexible shell 10 is relatively small, but its ability to restrain the battery cell 100 is poor. When the high-temperature airflow generated by the electrode assembly 20 carries solid particles and liquid substances inside the flexible shell 10 and forms a high-temperature gas flow that is sprayed out of the flexible shell 10, the protective effect of the flexible shell 10 is limited, and it is impossible to control the spray direction of the high-temperature gas flow. This will damage the insulation interface of the battery device 200 and easily cause secondary damage.

[0114] Based on this, this application proposes a battery cell 100, which has a pressure relief region 121 on at least the circumferential surface 12 of the flexible shell 10, so that the battery cell 100 can achieve directional pressure relief within the pressure relief region 121, so that the high-temperature gas flow in the event of thermal runaway of the battery cell 100 can be discharged through the pressure relief region 121, thereby guiding the direction of the gas flow, reducing the probability of insulation interface damage and secondary damage caused by thermal runaway, slowing down the spread of thermal runaway, and improving the reliability of the battery cell 100.

[0115] The battery cell 100, battery device 200, and electrical appliance 300 according to embodiments of this application are described below with reference to Figures 1-14.

[0116] As shown in Figures 3, 5 and 7, this application provides a battery cell 100, including: a flexible housing 10 and an electrode assembly 20, wherein the electrode assembly 20 is disposed within the flexible housing 10.

[0117] As shown in Figures 4, 6 and 8, the flexible housing 10 has a side surface 11 opposite to the large surface of the electrode assembly 20, and a circumferential surface 12 that avoids the large surface. The circumferential surface 12 is circumferentially connected to the side surface 11 around the electrode assembly 20. At least the circumferential surface 12 is provided with a pressure relief area 121.

[0118] The electrode assembly 20 may include one or more bare cells, which may be configured as wound cores or stacked cores. During the stacking or winding of the bare cells, the surface with the largest surface area is formed to define the large surface of the electrode assembly 20, while other surfaces with smaller surface areas surround the periphery of the large surface and are used to define the peripheral surface of the electrode assembly 20. The flexible housing 10 is used to accommodate the electrode assembly 20. The flexible housing 10 has a side surface 11 opposite to the large surface and a circumferential surface 12 opposite to the peripheral surface.

[0119] This application provides a pressure relief area 121 on at least the circumferential surface 12. That is, the pressure relief area 121 can be provided on one side 11, two sides 11, one circumferential surface 12, multiple circumferential surfaces 12, or both sides 11 and circumferential surfaces 12. By providing the pressure relief area 121, the battery cell 100 can be depressurized through the pressure relief area 121. The pressure relief area 121 can be provided on a suitable surface of the flexible shell 10, thereby depressurizing the battery cell 100 and achieving safety protection for the battery cell 100. Depressurization through the pressure relief area 121 can achieve directional pressure relief of the battery cell 100, that is, pressure relief is only carried out through the pressure relief area 121. During the pressure relief process, the discharge inside the battery cell 100 can be guided to achieve orderly discharge.

[0120] According to the embodiments of this application, the battery cell 100 is provided with a pressure relief area 121 on the flexible shell 10 to achieve directional pressure relief of the battery cell 100 in the event of thermal runaway. This enables the orderly discharge of high-temperature gas flow inside the battery cell 100, thereby reducing damage to the insulation interface of the battery device 200, reducing secondary damage, and improving the reliability of the battery cell 100 and even the battery device 200.

[0121] The insulation interface of the battery device 200 includes: insulation structure between adjacent battery cells 100, insulation structure between adjacent battery packs 500, insulation structure between battery packs 500 and surrounding components, etc. By realizing the orderly discharge of high-temperature gas flow, the impact on the insulation interface when the battery cells 100 are depressurized can be reduced, thereby reducing the probability of secondary damage and improving reliability.

[0122] Referring to Figures 3, 5 and 7, according to some embodiments of this application, the pressure relief zone 121 includes a weak portion 122 disposed on the circumferential surface 12, the weak portion 122 being configured to rupture to relieve pressure when the pressure inside the flexible housing 10 exceeds a pressure threshold.

[0123] The weak part 122 can be formed as a weakened connection structure such as a notch. When the internal pressure of the flexible shell 10 exceeds the pressure threshold, the weakened connection structure can preferentially suffer structural damage (i.e., breakage) to form a pressure relief port on at least one surface of the flexible shell 10, and achieve directional pressure relief through the pressure relief port.

[0124] Therefore, by setting the weak part 122, the pressure relief area 121 formed on the circumferential surface 12 can relieve pressure in time when the battery cell 100 experiences thermal runaway, thereby improving reliability. At the same time, the pressure relief part 520 is located on the circumferential surface 12, and the position of the pressure relief part 520 is more reasonable, which can realize directional pressure relief along the circumferential surface 12. The reasonable pressure relief direction can reduce the impact on surrounding components, especially adjacent battery cells 100, during the pressure relief process, and further improve the reliability of the battery cell 100.

[0125] The flexible shell 10 covers the outside of the electrode assembly 20. The flexible shell 10 can be configured as a rolled-up covering structure and can form creases on the circumferential surface 12 or the side surface 11. The weak part 122 can be provided on the circumferential surface 12. For example, the weak part 122 can be configured as a weakened connection structure, and at least part of the crease is connected by the weakened connection structure. Alternatively, the weak part 122 can be provided separately, and the pressure relief area 121 and the crease can be located on the same surface or on different surfaces.

[0126] As shown in Figures 9, 10 and 11, according to some embodiments of this application, the membrane material of the flexible shell 10 is a stacked multilayer membrane structure, and includes at least a metal barrier layer a, a weak portion 122 is formed in the metal barrier layer a, or the weak portion 122 extends through at least a portion of the metal barrier layer a.

[0127] In some embodiments, the weak portion 122 is formed on the metal barrier layer a, such that the structural strength of the region where the weak portion 122 is located is lower than the structural strength of other regions, allowing the region to fracture preferentially to achieve directional pressure relief. In other embodiments, the weak portion 122 is formed on the side of the flexible housing 10 away from the electrode assembly 20 and extends toward and through at least a portion of the metal barrier layer a, such that the structural strength of the region where the weak portion 122 is located is lower than the structural strength of other regions, allowing the region to fracture preferentially to achieve directional pressure relief.

[0128] The membrane material of the flexible shell 10 refers to the material of the flexible shell 10 itself. The membrane material itself is a multi-layer membrane structure. The metal barrier layer a in the multi-layer membrane structure can improve the structural strength of the flexible shell 10, reduce the probability of the electrode assembly 20 puncturing the flexible shell 10, and improve the reliability of the battery cell 100. The weak part 122 is formed on the metal barrier layer a or penetrates into the metal barrier layer a, which can reduce the processing difficulty of the weak part 122 and make the stability and reliability of the weak part 122 higher.

[0129] Referring to Figures 4, 6, 8 and 12, according to some embodiments of this application, the weak portion 122 is constructed as a groove that penetrates at least a portion of the metal barrier layer a.

[0130] The weak part 122 can be constructed as a groove, and the groove can be processed onto the circumferential surface 12 or side surface 11 of the flexible shell 10 by means of laser etching, shaving, etc., and the groove penetrates at least a portion of the metal barrier layer a, so that when the internal pressure of the flexible shell 10 is applied to the area where the groove is located, the groove can break preferentially to achieve directional pressure relief.

[0131] Thus, in the embodiment where the weak portion 122 is constructed as a groove, the groove only penetrates to at least a portion of the metal barrier layer a, and the groove extends from the side surface of the flexible shell 10 away from the electrode assembly 20 toward the side surface of the flexible shell 10 adjacent to the electrode assembly 20, thereby achieving structural weakening in a partial area. While forming the weak portion 122, the insulation effect between the metal barrier layer a and the interior of the flexible shell can remain stable, and the reliability and stability of the battery cell 100 can also be improved.

[0132] As shown in Figures 3-8, according to some embodiments of this application, the outline shape of the groove is one or more of the following: circular, elliptical, rectangular, straight, and Z-shaped.

[0133] In the embodiments shown in Figures 3 and 4, the groove is in the shape of a straight line and extends along the length direction of the circumferential surface 12 or the side surface 11, and is located on one side of the fold of the flexible shell 10. In the embodiments shown in Figures 5 and 6, the groove is in the shape of a straight line and extends along the width direction of the circumferential surface 12 or the side surface 11, and is located on both sides of the fold of the flexible shell 10. In the embodiments shown in Figures 7 and 8, the groove is in the shape of a circle and can be located on both sides of the fold of the flexible shell 10.

[0134] This application does not impose specific restrictions on the structural shape of the grooves. Those skilled in the art can process grooves of appropriate shapes on a suitable surface of the flexible shell 10 according to the groove opening requirements.

[0135] In this way, by setting a groove of a suitable shape as a weak part 122, not only can the processing difficulty be reduced, thereby reducing the production cost of the battery cell 100, but the groove can also be set at a suitable position on a suitable surface to achieve directional pressure relief, which can further improve the reliability of the battery cell 100.

[0136] According to some embodiments of this application, there are multiple notches, which are spaced apart on the circumferential surface 12 or the side surface 11 of the flexible housing 10.

[0137] In embodiments where the etched mark is a straight line extending along the length of the circumferential surface 12 or the side surface 11, there can be multiple etched marks, which can be spaced apart along the width of the circumferential surface 12 or the side surface 11. In embodiments where the etched mark is a straight line extending along the width of the circumferential surface 12 or the side surface 11, there can be multiple etched marks, which can be spaced apart along the length of the circumferential surface 12 or the side surface 11. In embodiments where the etched mark is a closed shape such as a circle or ellipse, there can be multiple etched marks spaced apart along both the length and width of the circumferential surface 12 or the side surface 11.

[0138] Therefore, by setting multiple grooves at intervals on the circumferential surface 12 or the side surface 11, rapid pressure relief can be achieved under the premise of directional (i.e., the direction pointed to by the surface where the groove is located) pressure relief, so as to reduce the impact during the pressure relief process. Moreover, the force distribution on the surface where multiple grooves are located is more uniform, and the pressure relief response speed and reliability can also be higher.

[0139] As shown in Figures 9 and 12, according to some embodiments of this application, the film thickness of the flexible shell 10 is D1, the groove depth is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

[0140] For example, if the membrane thickness is 3mm, the scribing depth is 1mm to 2mm (including the endpoint value).

[0141] In this way, the depth of the scribing is not less than one-third of the film thickness, which can avoid the scribing depth being too shallow, so that the weak part 122 has a better priority breaking effect compared with other areas of the flexible shell 10, and the reliability and stability of the pressure relief area 121 are better. At the same time, the depth of the scribing is not greater than two-thirds of the film thickness, which can avoid the scribing being too deep, so as to take into account the structural strength of the flexible shell 10 and reduce the probability of false triggering of the weak part 122.

[0142] As shown in Figure 10, according to some embodiments of this application, the membrane material of the flexible shell 10 includes: a metal barrier layer a, a first plasticized barrier layer b located on the side of the metal barrier layer a facing the electrode assembly 20, and a second plasticized barrier layer c on the side away from the electrode assembly 20. The metal barrier layer a includes a body region a1 and a weak region a2 corresponding to the weak portion 122. The weak region a2 is made of a different material than the body region a1.

[0143] The flexible outer shell 10 has a symmetrical structure, namely, a first plasticized barrier layer b and a second plasticized barrier layer c are respectively provided on the side of the metal barrier layer a facing the electrode assembly 20 and the side away from the electrode assembly 20. The materials of the first plasticized barrier layer b and the second plasticized barrier layer c can be the same or different, but they are both constructed as plastic parts, with certain structural strength and insulation performance. This improves the structural strength of the flexible outer shell 10 while achieving insulation between the electrode assembly 20 and the metal barrier layer a, and between the metal barrier layer a and external components, thereby improving the insulation reliability and stability of the battery cell 100.

[0144] A first adhesive layer d is provided between the first plasticized barrier layer b and the metal barrier layer a, and a second adhesive layer e is provided between the second plasticized barrier layer c and the metal barrier layer a, so as to improve the connection strength and structural stability between the first plasticized barrier layer b and the metal barrier layer a, and between the second plasticized barrier layer c and the metal barrier layer a. Furthermore, by making the materials of the weak region a2 and the main body region a1 different, and the structural strength of the main body region a1 is higher than that of the weak region a2, the weak region a2 with lower structural strength is formed as the weak part 122. When the internal pressure of the flexible shell 10 exceeds the pressure threshold, the weak part 122 can preferentially cause the main body region a1 to rupture, thereby achieving directional pressure relief.

[0145] In some embodiments, the weak portion 122 of this application is defined by the weak region a2 of the metal barrier layer a, and the weak region a2 and the body region a1 are made of different materials to achieve a differentiated setting of structural strength between the weak portion 122 and the body region a1. While achieving the above-mentioned technical effects, the outer surface of the flexible shell 10 can be flatter, which can improve the surface flatness of the battery cell 100 and reduce the probability of scratches between it and surrounding components.

[0146] As shown in Figure 11, according to some embodiments of this application, the membrane material of the flexible shell 10 includes: a metal barrier layer a, a first plasticized barrier layer b located on the side of the metal barrier layer a facing the electrode assembly 20, and a second plasticized barrier layer c located on the side away from the electrode assembly 20. The metal barrier layer a includes a body region a1 and a weak region a2 corresponding to the weak portion 122. The thickness of the weak region a2 is less than the thickness of the body region a1.

[0147] The structure of the weak part 122 in this embodiment is not limited to the above-mentioned markings or the weak area a2 and the main body area a1 being made of different materials. Alternatively, the main body area a1 and the weak area a2 can be made of the same material, but the thickness of the weak area a2 can be less than the thickness of the main body area a1. This can also achieve a structural strength difference setting between the main body area a1 and the weak area a2, thereby achieving the same technical effect as the above embodiment.

[0148] The weak portion 122 of this application is defined by the weak region a2 of the metal barrier layer a, and the thickness of the weak region a2 is different from that of the main body region a1, so as to achieve the differentiated setting of structural strength between the weak portion 122 and the main body region a1. While achieving the above-mentioned technical effects, it can also reduce the processing difficulty of the thinned portion and reduce material costs.

[0149] As shown in Figure 11, according to some embodiments of this application, the membrane material further includes: a filling layer f, which is located between the first plasticized barrier layer b and the metal barrier layer a and fills the weak region a2, and / or the filling layer f is located between the second plasticized barrier layer c and the metal barrier layer a and is used to fill the weak region a2.

[0150] The thinner portion a2 relative to the body region a1 is used to define the thinner part 122. The thinned portion of the thinner portion of the thinner portion of the thinner portion relative to the body region a1 can be located on the side away from the electrode assembly 20, and the filling layer f is filled on the side of the thinner portion a2 away from the electrode assembly 20. Alternatively, the thinned portion can be located on the side facing the electrode assembly 20, and the filling layer f is filled on the side of the thinner portion a2 facing the electrode assembly 20. The thinner part 122 can also include a first part and a second part. The first part is located on the side of the thinner portion a2 facing the electrode assembly 20, and the second part is located on the side of the thinner portion a2 away from the electrode assembly 20. The filling layer f is provided in both the first part and the second part.

[0151] Therefore, by setting the filling layer f, the flatness of the surface of the flexible housing 10 facing the electrode assembly 20 and the surface away from the electrode assembly 20 can be improved, the probability of scratches between the flexible housing 10 and surrounding components (such as scratching the electrode assembly 20) can be reduced, and the reliability of the flexible housing 10 can be improved.

[0152] According to some embodiments of this application, the battery cell is any one of lithium iron phosphate battery, ternary lithium battery cell, and solid-state battery cell.

[0153] In other words, in some embodiments, the battery cell is constructed as a lithium iron phosphate battery cell, in some embodiments, the battery cell is constructed as a ternary lithium battery cell, and in some embodiments, the battery cell is constructed as a solid-state battery cell.

[0154] It is understood that in the embodiments of this application where the battery cell is constructed as a solid-state battery cell, the solid-state battery cell can be any one of oxide solid-state battery, sulfide solid-state battery, or hybrid polymer solid-state battery.

[0155] Thus, in the embodiments of this application that are constructed as lithium iron phosphate battery cells, the reliability of the battery cells can be improved and the cycle life of the battery cells can be extended. In the embodiments of this application that are constructed as ternary lithium battery cells, the energy density of the battery cells can be improved and the driving range can be increased. In the embodiments of this application that are constructed as solid-state battery cells, not only the energy density can be improved, but also the reliability can be improved.

[0156] According to some embodiments of this application, when the battery cell is a lithium iron phosphate (LiFeO4) battery cell, the ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent in the positive electrode material of the battery cell is 96:(1-3):(1-3); when the battery cell is a ternary lithium battery cell, the ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent in the positive electrode material of the battery cell is 96:(2-3):(1-2).

[0157] For example, in embodiments where the battery cell is a lithium iron phosphate battery cell, the ratio of the positive electrode active material, the positive electrode binder, and the positive electrode conductive agent can be 96:1:3, 96:3:1, 96:2:2, etc., preferably 96:2:2, and the positive electrode active material is lithium iron phosphate, the positive electrode binder is polyvinylidene fluoride, and the positive electrode conductive agent is conductive carbon black.

[0158] In embodiments where the battery cell is a ternary lithium battery cell, the ratio of the positive electrode active material, the positive electrode binder, and the positive electrode conductive agent can be 96:2:2, 96:3:1, etc., preferably 96:2.5:1.5, and the positive electrode active material is LiNi0.8Co0.1Mn0.1O2, the positive electrode binder can be polyvinylidene fluoride, and the positive electrode conductive agent can be conductive carbon black.

[0159] Therefore, in the embodiments where the battery cell is constructed as a lithium iron phosphate battery cell, the positive electrode active material, positive electrode binder, and positive electrode conductive agent are formulated in the above ratio, which can improve the electrochemical performance and mechanical stability of the battery cell. In the embodiments where the battery cell is constructed as a ternary lithium battery cell, the positive electrode active material, positive electrode binder, and positive electrode conductive agent are formulated in the above ratio, which can improve the energy density and cycle life of the battery.

[0160] As shown in Figure 2, this application provides a battery device 200, including: a housing 400 and a battery pack 500. The battery pack 500 is at least one, and the battery pack 500 includes: at least one battery cell 100 as described in the above embodiments and a cover shell 510. At least one side surface of the cover shell 510 has a pressure relief portion 520.

[0161] Referring to Figures 13 and 14, a housing space is formed inside the housing 400, and one or more battery packs 500 are disposed in the housing space. Each battery pack 500 has one or more battery cells 100 disposed inside the housing 510, and the battery cells 100 are constructed as described above using the flexible housing 10.

[0162] The casing 510 is used to cover at least one of the more than 100 circumferential surfaces 12 of the battery cell 100 and two side surfaces 11. A weak portion 122 is provided on at least one circumferential surface 12 of the battery cell 100. At least one side of the casing 510 is formed with a pressure relief portion 520, such as the pressure relief portion 520 being opposite to the weak portion 122, or the pressure relief portion 520 being located on a first surface of the casing 510, while the weak portion 122 is opposite to a second surface of the casing 510, and the first surface and the second surface are adjacent.

[0163] According to the battery device 200 of the present application embodiment, by providing a pressure relief part 520 on the casing 510 that cooperates with the pressure relief region 121, when the battery cell 100 experiences thermal runaway, the high-temperature gas flow discharged through the pressure relief region 121 (weak part 122) can be further released outward through the pressure relief part 520. In order to improve the reliability of the battery device 200, the cooperation between the weak part 122 and the pressure relief part 520 can achieve directional discharge of the high-temperature gas flow.

[0164] Referring to Figures 13 and 14, according to some embodiments of this application, the cover shell 510 includes a first plate 511 and a second plate 512 located on both sides of the first plate 511. A pressure relief portion 520 is formed on the first plate 511, and the pressure relief area 121 is at least partially opposite to the pressure relief portion 520.

[0165] The first plate 511 and the second plates 512 located on both sides of the first plate 511 define a generally U-shaped casing 510, such that the first plate 511 of the casing 510 can be opposite to one circumferential surface 12 of the battery cell 100, and the two second plates 512 can be opposite to the two side surfaces 11 of the battery cell 100 respectively. The weak portion 122 formed on the circumferential surface 12 can be at least partially opposite to the pressure relief portion 520 formed on the first plate 511.

[0166] The pressure relief area 121 and the pressure relief portion 520 are at least partially opposite each other, meaning that the weak portion 122 formed on the circumferential surface 12 projects toward the first plate 511 and the projected outline at least partially overlaps with the outline of the pressure relief portion 520.

[0167] In this way, on the one hand, the gas and fire generated after thermal runaway of the battery cell 100 can be discharged in a directional manner, achieving orderly discharge to reduce damage, especially secondary damage. On the other hand, the connection path between the pressure relief zone 121 and the pressure relief section 520 is shorter, which can achieve rapid discharge while the gas and fire remain inside the casing 510 for a shorter time, thus having less impact on other battery cells 100 around the thermally runaway battery cell 100. It can also further reduce the spread rate of thermal runaway and improve the reliability of the battery pack 500 and the battery device 200.

[0168] According to some embodiments of this application, the second plate 512 is opposite to the side 11, and the projected outline area of ​​the second plate 512 toward the side 11 of the flexible shell 10 is less than or equal to the area of ​​the side 11.

[0169] The circumferential surface 12 is defined as including a first surface and a second surface opposite to it. The first surface is opposite to the first plate 511, and the second surface is disposed away from the first plate 511. The second surface is used to connect to the housing 400. The two sides of the first surface and the second surface are the two side surfaces 11 of the battery cell 100, and the two ends of the first surface and the second surface are the other two circumferential surfaces 12 of the battery cell 100. The second plate 512 is opposite to the side surface 11 to limit the battery cell 100 in the direction of the second plate 512. The area of ​​the surface of the second plate 512 opposite to the side surface 11 can be less than or equal to the area of ​​the side surface 11.

[0170] In some embodiments, the size of the second plate 512 is the same as the size of the side 11. In other embodiments, the size of the second plate 512 is smaller than the size of the side 11. On the one hand, this can avoid the second plate 512 being too large, which would prevent the second side from being connected to the housing 400. This can improve the stability and reliability of the battery pack 500 within the housing 400. On the other hand, the second plate 512 can use less material, which can also reduce the material cost of the battery pack 500 and the battery device 200.

[0171] As shown in FIG13, according to some embodiments of the present application, the first plate 511 is spaced apart from the side of the circumferential surface 12 having the weak portion 122 to define the exhaust passage 530.

[0172] In this way, the high-temperature gas flow generated after the weak part 122 ruptures can be first released to the exhaust channel 530, and after being initially buffered by the exhaust channel 530, it can be discharged through the pressure relief part 520, which can reduce the pressure of the high-temperature gas flow after it flows out of the pressure relief part 520, thereby reducing the impact and damage after the battery cell 100 thermal runaway.

[0173] According to some embodiments of this application, the first plate 511 is constructed as a flat plate or an arc plate.

[0174] In some embodiments, the first plate 511 is constructed as a flat plate, and in other embodiments, the first plate 511 is constructed as an arc-shaped plate.

[0175] According to some embodiments of this application, there are multiple pressure relief sections 520, which are spaced apart in the length direction and / or width direction of the first plate 511.

[0176] Therefore, each of the multiple weak points 122 on each battery cell 100 can have a corresponding pressure relief part 520, so that the high-temperature gas flow buffered by the exhaust channel 530 can be directly discharged through the corresponding pressure relief part 520, thereby increasing the discharge speed and reducing the residence time of the high-temperature gas flow in the exhaust channel 530 during the discharge process, thereby reducing the spread speed of thermal runaway between adjacent battery cells 100 in the battery pack 500 and improving the reliability of the battery pack 500.

[0177] According to some embodiments of this application, the casing 510 is constructed as an aluminum casing or a stainless steel casing.

[0178] In some embodiments, the casing 510 is constructed of aluminum, and in other embodiments, the casing 510 is constructed of stainless steel, so that the temperature resistance and structural strength of the casing 510 are much higher than those of the flexible casing. By using the casing 510 with a certain structural strength and rigidity to support and protect the battery cell 100 outside the battery cell 100, the structural strength of the battery pack 500 can be improved, the thermal runaway propagation rate between adjacent battery packs 500 can be reduced, and the reliability of the battery device 200 can be improved.

[0179] Referring to Figure 14, according to some embodiments of this application, the housing 400 has a bottom plate 410, which is connected to the battery cell 100 via an adhesive layer 420.

[0180] The bottom plate 410 of the housing 400 is connected to the second side of the battery cell 100 through an adhesive layer 420 to fix the battery pack 500 on the housing 400, thereby improving the fixation stability and reliability of the battery pack 500.

[0181] Of course, in some embodiments, the adhesive layer 420 is also used for the connection and fixation between the base plate 410 and the second plate 512.

[0182] Referring to Figure 14, according to some embodiments of this application, the base plate 410 is constructed as a cold plate, and / or the base plate 410 is provided with a cold plate on the side facing the plurality of battery cells 100, and the adhesive layer 420 is located between the cold plate and the plurality of battery cells 100.

[0183] In some embodiments, the bottom plate 410 of the housing 400 is formed as a cold plate, and the cold plate is connected to the battery cell 100 through an adhesive layer 420. In other embodiments, a cold plate is provided between the bottom plate 410 and the battery cell 100, and the cold plate is connected to the battery cell 100 through an adhesive layer 420.

[0184] The adhesive layer 420 is constructed as structural adhesive, and the base plate 410, which is constructed as a cold plate, or the base plate 410 equipped with a cold plate, is connected to the battery cell 100. Under the premise of ensuring that the battery pack 500 is stably and reliably fixed in the housing 400, the temperature of the battery pack 500 can also be regulated by the cold plate, so that the battery pack 500 can operate at a suitable temperature. This can improve the working stability and reliability of the battery pack 500, reduce the probability of the battery pack 500 overheating, reduce the probability of the battery pack 500 thermal runaway, and thus improve the reliability of the battery pack 500 and even the battery device 200.

[0185] As shown in FIG14, according to some embodiments of the present application, the adhesive layer 420 includes an adhesive layer body 421 and an overflow portion 422. The overflow portion 422 is located on the side of the adhesive layer body 421 facing the plurality of battery cells 100, and is located between adjacent battery cells 100, and / or between the battery cells 100 and the second plate 512.

[0186] When structural adhesive is used to connect and fix the battery cell 100 to the cold plate, at least a portion of the adhesive layer 420 overflows between adjacent battery cells 100 and / or between the second plate 512 and the battery cell 100, forming an overflow portion 422. The overflow portion 422 not only increases the area between the adhesive layer 420 and the battery cell 100 and between the adhesive layer 420 and the second plate 512, thereby improving the fixing stability and reliability of the battery pack 500 on the housing 400, but also fills the gaps between adjacent battery cells 100 and between the battery cell 100 and the second plate 512, thereby limiting the position of the battery cell 100 and the housing 510, reducing the movement of the battery pack 500 within the housing 400, and reducing the movement of the battery cell 100 within the housing 510.

[0187] As shown in the accompanying drawings, the battery cell 100 of this embodiment is configured as a pouch battery cell 100, the electrode assembly 20 is disposed inside the flexible shell 10, the flexible shell 10 has a weak portion 122 formed on at least the circumferential surface 12, the battery pack 500 includes at least one battery cell 100 of this embodiment, and the pressure relief portion 520 on the first plate 511 of the shell 510 is at least partially opposite to the weak portion 122, the second plate 512 is opposite to the side 11 of the flexible shell 10, the bottom plate 410 of the housing 400 is configured as a cold plate, or a cold plate is disposed on the top of the bottom plate 410, the cold plate is connected to the battery cell 100 through an adhesive layer 420, the overflow portion 422 of the adhesive layer 420 overflows between adjacent battery cells 100, and / or between the battery cell 100 and the second plate 512.

[0188] This application proposes an electrical device 300, including: the battery device 200 in the above embodiments.

[0189] Furthermore, as shown in Figure 1, the electrical equipment 300 can be a vehicle, and the battery device 200 can be integrated into the vehicle chassis. That is, the vehicle body structure is a split body, with the upper body and the integrated intelligent chassis assembled together. The battery device 200 is formed as part of the integrated intelligent chassis. In this way, the top plate of the box 400 can also participate in defining the vehicle floor, which can save the meaningless stacking of multiple layers of sheet materials, reduce material costs, and make the space occupation of the chassis more reasonable. The space inside the chassis for accommodating the battery device 200 is larger and the energy density is higher.

[0190] It is understandable that the electrical equipment 300 is constructed as a vehicle, that is, the vehicle uses the aforementioned battery device 200. The battery device 200 has higher energy density and higher reliability, which can improve the vehicle's driving range and driving reliability.

[0191] Other configurations and operations of the battery cell 100, battery device 200, and electrical equipment 300 according to the embodiments of this application are known to those skilled in the art and will not be described in detail here.

[0192] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0193] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, wherein, include: Flexible shell (10); Electrode assembly (20) is disposed within the flexible housing (10); The flexible outer shell (10) has a side surface (11) opposite to the large surface of the electrode assembly (20) and a circumferential surface (12) avoiding the large surface. The circumferential surface (12) and the side surface (11) are circumferentially connected around the electrode assembly (20). At least the circumferential surface (12) is provided with a pressure relief area (121).

2. The battery cell of claim 1, wherein, The pressure relief zone (121) includes a weak portion (122) disposed on the circumferential surface (12), the weak portion (122) being configured to rupture to relieve pressure when the pressure inside the flexible housing (10) exceeds a pressure threshold.

3. The battery cell of claim 2, wherein, The flexible outer shell (10) has a membrane structure consisting of stacked multilayer membranes and includes at least a metal barrier layer (a). The weak portion (122) is formed in the metal barrier layer (a) or the weak portion (122) extends through at least a portion of the metal barrier layer (a).

4. The battery cell of claim 2 or 3, wherein, The weak portion (122) is constructed as a groove that penetrates at least a portion of the metal barrier layer (a).

5. The battery cell of claim 4, wherein, The outline shape of the engraving is one or more of the following: circular, elliptical, rectangular, straight, and Z-shaped.

6. The battery cell of claim 4, wherein, The grooves are multiple and are spaced apart on the circumferential surface (12) or the side surface (11).

7. The battery cell of any one of claims 4-6, wherein, The thickness of the film material of the flexible shell (10) is D1, the depth of the groove is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

8. The battery cell of claim 2, wherein, The flexible shell (10) includes a metal barrier layer (a), a first plasticized barrier layer (b) located on the side of the metal barrier layer (a) facing the electrode assembly (20), and a second plasticized barrier layer (c) located away from the electrode assembly (20). The metal barrier layer (a) includes a body region (a1) and a weak region (a2) corresponding to the weak part (122). The weak region (a2) is made of a different material than the body region (a1).

9. The battery cell of claim 2, wherein, The flexible shell (10) includes a metal barrier layer (a), a first plasticized barrier layer (b) located on the side of the metal barrier layer (a) facing the electrode assembly (20), and a second plasticized barrier layer (c) located away from the electrode assembly (20). The metal barrier layer (a) includes a body region (a1) and a weak region (a2) corresponding to the weak part (122). The thickness of the weak region (a2) is less than the thickness of the body region (a1).

10. The battery cell of claim 9, wherein, The membrane material further includes: a filling layer (f), the filling layer (f) being located between the first plasticized barrier layer (b) and the metal barrier layer (a) and filling the weak region (a2), and / or the filling layer (f) being located between the second plasticized barrier layer (c) and the metal barrier layer (a) and used to fill the weak region (a2).

11. The battery cell of any one of claims 1-10, wherein, The battery cell is any one of lithium iron phosphate battery cell, ternary lithium battery cell, and solid-state battery cell.

12. The battery cell of claim 11, wherein, When the battery cell is a lithium iron phosphate battery cell, the ratio of positive electrode active material, positive electrode binder, and positive electrode conductive agent in the positive electrode material of the battery cell is 96:1-3:1-3; when the battery cell is a ternary lithium battery cell, the ratio of positive electrode active material, positive electrode binder, and positive electrode conductive agent in the positive electrode material of the battery cell is 96:2-3:1-2.

13. A battery device, wherein, include: Box (400); A battery pack (500), wherein the battery pack (500) is at least one, the battery pack (500) comprising: at least one battery cell according to any one of claims 1-12 and a casing (510), wherein at least one side surface of the casing (510) has a pressure relief portion (520).

14. The battery device of claim 13, wherein, The covering shell (510) includes a first plate (511) and a second plate (512) located on both sides of the first plate (511). The pressure relief portion (520) is formed on the first plate (511), and the pressure relief area (121) is at least partially opposite to the pressure relief portion (520).

15. The battery device of claim 14, wherein, The second plate (512) is opposite to the side (11), and the projected outline area of ​​the second plate (512) facing the side (11) of the flexible shell (10) is less than or equal to the area of ​​the side (11).

16. The battery device of claim 14, wherein, The first plate (511) is spaced apart from the side of the circumferential surface (12) having the weak portion (122) to define an exhaust passage (530).

17. The battery device of claim 14, wherein, The first plate (511) is constructed as a flat plate or an arc plate.

18. The battery device of claim 13, wherein, There are multiple pressure relief sections (520), and the multiple pressure relief sections (520) are spaced apart in the length direction and / or width direction of the first plate (511).

19. The battery device of claim 13, wherein, The covering shell (510) is constructed of aluminum or stainless steel.

20. The battery device of claim 14, wherein, The housing (400) has a base plate (410), which is connected to the battery cell via an adhesive layer (420).

21. The battery device of claim 20, wherein, The base plate (410) includes a cold plate, and the adhesive layer (420) is located between the cold plate and the plurality of battery cells.

22. The battery device of claim 20, wherein, The adhesive layer (420) includes an adhesive layer body (421) and an overflow portion (422), wherein the overflow portion (422) is located on the side of the adhesive layer body (421) facing the plurality of battery cells, and is located between adjacent battery cells, and / or between the battery cells and the second plate (512).

23. An electrical device, comprising: include: The battery device according to any one of claims 13-22.

24. The powered device of claim 23, wherein, The electrical equipment in question is a vehicle.

25. The powered device of claim 23, wherein, The battery device is integrated into the chassis of the vehicle, and the top plate of the housing (400) participates in defining the vehicle floor.

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