Battery apparatus and electrical device

Abstract

A battery apparatus. A plurality of pouch battery cells (10) are sequentially stacked and electrically connected; a wrapping housing (20) is wrapped outside the plurality of pouch battery cells (10), and the wrapping housing (20) is configured to constrain the plurality of pouch battery cells (10) at least from three directions; the strength of the wrapping housing (20) is greater than the strength of a flexible casing of each pouch battery cell (10); and the thickness of a panel body of the wrapping housing (20) constraining the plurality of pouch battery cells (10) is less than or equal to 5.2 mm and greater than or equal to 0.2 mm.

Description

Battery devices and electrical equipment Technical Field

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

[0002] In related technologies, there is a high difficulty in thermal protection between adjacent battery packs in pouch battery devices, which affects the further improvement of the reliability of pouch battery devices. Summary of the Invention

[0003] This application aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this application is to provide a battery device and an electrical appliance that has higher reliability and better resistance to thermal runaway.

[0004] In a first aspect, this application provides a battery device, comprising: a plurality of pouch battery cells and a casing, wherein the plurality of pouch battery cells are stacked sequentially and electrically connected; the casing covers the plurality of pouch battery cells and is configured to constrain the plurality of pouch battery cells from at least three directions; the strength of the casing is higher than the strength of the flexible outer shell of the pouch battery cells; wherein the thickness of the casing constraining the plurality of pouch battery cells is less than or equal to 5.2 mm and greater than or equal to 0.2 mm.

[0005] According to the battery device of the present application embodiment, by making the strength of the outer shell higher than that of the flexible outer shell and making the thickness of the outer shell more reasonable, on the one hand, the structural strength of the outer shell can be improved, the probability of structural damage to the outer shell after being impacted by high-pressure gas flow can be reduced, so that the heat diffusion of the soft-pack battery cells is concentrated inside the outer shell and the probability of heat diffusion outside the outer shell is reduced, thereby improving the reliability of the battery device. On the other hand, the energy density of the battery device can be taken into account, and the production cost of the battery device can be reduced.

[0006] According to some embodiments of this application, the thickness of the shell constraining multiple pouch battery cells is less than or equal to 3 mm and greater than or equal to 0.5 mm.

[0007] According to some embodiments of this application, the thickness of the shell constraining multiple pouch battery cells is less than or equal to 1 mm and greater than or equal to 0.6 mm.

[0008] According to some embodiments of this application, the casing is an aluminum casing, and the casing constrains the thickness of the multiple pouch battery cells to be less than or equal to 1 mm and greater than or equal to 0.4 mm; or the casing is a stainless steel casing, and the casing constrains the thickness of the multiple pouch battery cells to be less than or equal to 1 mm and greater than or equal to 0.2 mm.

[0009] According to some embodiments of this application, the casing includes a first plate, a second plate, and a third plate that are bent and connected in sequence, with an opening formed on the side of the first plate and the third plate away from the second plate; the casing is connected to the housing of the battery device through the opening; the first plate, the second plate, and the third plate respectively constrain multiple pouch battery cells in three directions.

[0010] According to some embodiments of this application, the first plate and the third plate constrain multiple pouch cell units in opposite directions.

[0011] According to some embodiments of this application, the direction in which the second plate constrains the plurality of pouch cell units is perpendicular to the direction in which the first plate or the third plate constrains the plurality of pouch cell units.

[0012] According to some embodiments of this application, the first plate, the second plate and the third plate each form two openings on two sides in a third direction, and each opening is provided with a busbar for merging multiple soft-pack battery cells, and each busbar covers the corresponding opening.

[0013] According to some embodiments of this application, the battery device further includes: a housing, wherein the end faces of the first plate and the third plate away from the second plate are connected to the housing by an adhesive layer.

[0014] According to some embodiments of this application, the box has a bottom plate, which is connected to the first plate and the third plate by an adhesive layer.

[0015] According to some embodiments of this application, the base plate is constructed as a cold plate, and / or a cold plate is provided on the side of the base plate facing the multiple soft-pack battery cells, with an adhesive layer located between the cold plate and the multiple soft-pack battery cells.

[0016] 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 pouch cell units, and located between adjacent pouch cell units, and / or between a pouch cell unit and a first plate, and / or between a pouch cell unit and a third plate.

[0017] The large surface opposite the side surface and the circumferential surface avoiding the large surface are provided with weak parts, and the covering shell has a pressure relief part that is at least partially opposite the weak part.

[0018] According to some embodiments of this application, a pressure relief section is formed on the second plate.

[0019] According to some embodiments of this application, the second plate is spaced apart from the side of the circumferential surface that has a pressure relief portion to define an exhaust passage.

[0020] According to some embodiments of this application, the second plate is constructed as a flat plate or an arc plate.

[0021] 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 second plate.

[0022] According to some embodiments of this application, the total charge of multiple pouch battery cells within a single casing is less than 0.9 kWh, and the energy density of the multiple pouch battery cells within a single casing satisfies: L ≤ 450 Wh / L.

[0023] According to some embodiments of this application, the total charge of multiple pouch battery cells within a single casing is less than 0.72 kWh, and the energy density of the multiple pouch battery cells within a single casing satisfies: 450 Wh / L < L ≤ 600 Wh / L.

[0024] According to some embodiments of this application, the total charge of multiple pouch battery cells within a single casing is less than 0.6 kWh, and the energy density of the multiple pouch battery cells within a single casing satisfies: 600 Wh / L < L ≤ 700 Wh / L.

[0025] According to some embodiments of this application, the total charge of multiple pouch battery cells within a single casing is less than 0.48 kWh, and the energy density of the multiple pouch battery cells within a single casing satisfies L greater than 700 Wh / L.

[0026] According to some embodiments of this application, the soft-pack battery cell is any one of lithium iron phosphate battery cell, ternary lithium battery cell, and solid-state battery cell.

[0027] According to some embodiments of this application, the battery cell is a lithium iron phosphate battery cell, and 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; the battery cell is a ternary lithium battery cell, and 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.

[0028] Secondly, this application provides 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 an electrical device according to an embodiment of this application;

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

[0035] Figure 3 is a schematic diagram of a battery pack according to an embodiment of this application;

[0036] Figure 4 is a schematic diagram of the cooperation between the battery pack and the housing according to an embodiment of this application;

[0037] Figure 5 is a schematic diagram of the cooperation between the busbar, battery cell, and casing according to an embodiment of this application;

[0038] Figure 6 is a schematic diagram of a single soft-pack battery cell according to an embodiment of this application. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] In some embodiments, the battery pack is typically formed by arranging multiple battery cells.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical equipment using battery devices.

[0052] 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.

[0053] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0054] 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 100 is installed inside the vehicle, and the battery device 100 can be located at the bottom, front, or rear of the vehicle. The battery device 100 can be used to power the vehicle; for example, the battery device 100 can serve as the vehicle's operating power source.

[0055] The vehicle may also include a controller 400 and a motor 300. The controller 400 controls the battery device 100 to supply power to the motor 300, which serves as a load, for example, for the power needs of the vehicle during starting, navigation and driving.

[0056] In some embodiments of this application, the battery device 100 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.

[0057] 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 includes a housing 40 for accommodating individual battery cells.

[0058] The housing 40 is a component that houses individual battery cells and provides space for the battery pack. The housing 40 can employ various structures. In some embodiments, the housing 40 may include a tray and a cover, which overlap to define a space for accommodating the individual battery cells. The tray and cover can be of various shapes, such as cuboids or cylinders. 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 overlapping the open side of the tray, thus forming the housing 40 with the storage 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 overlapping the open side of the tray, thus forming the housing 40 with the storage space.

[0059] As an example, the battery cell can be a pouch cell 10.

[0060] In the battery device 100, there can be one or more battery cells. Multiple battery cells are loaded into a battery pack by a casing 20, and one or more battery packs are loaded into a housing 40. If there are multiple battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form a battery pack, and then multiple battery packs can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 40.

[0061] Referring to Figures 5 and 6, the battery cell serves as the smallest energy unit of the battery device 100. The battery cell includes a flexible housing 11 and an electrode assembly 12 disposed within the flexible housing 11.

[0062] The internal environment formed by the flexible housing 11 can be used to accommodate the electrode assembly 12, electrolyte, and other components. An opening can be formed on one side of the flexible housing 11 for injecting electrolyte and for inserting the electrode assembly 12 into the housing.

[0063] As shown in Figures 2, 3, 5, and 6, the tabs of the electrode assembly 12 pass through the flexible shell 11 and are electrically connected to the busbar 30. The electrode assembly 12 is the component in the battery cell where the electrochemical reaction occurs. The flexible shell 11 may contain one or more electrode assemblies 12. The electrode assembly 12 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 containing active material constitute the main body of the electrode assembly 12, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte, and the tabs connect to the busbar 30 to form a current loop.

[0064] 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.

[0065] 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.

[0066] 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.).

[0067] As an example, when the pouch cell 10 of this application 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 pouch cell 10. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode film layer of the battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] When the soft-pack battery cell 10 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.

[0072] 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.

[0073] 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.

[0074] During the charging and discharging process, the soft-pack battery cell 10 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the soft-pack battery cell 10 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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%.

[0079] 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%.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.).

[0084] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in a pouch cell 10. 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 negative electrode films in batteries may also be used. These negative electrode films may be used alone or in combination of two or more.

[0085] 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 improve the energy density of the pouch cell 10.

[0086] 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 pouch cell 10 system, when the mass content of silicon is within the above range, the energy density of the pouch cell 10 can be improved.

[0087] 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.

[0088] 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%.

[0089] 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%.

[0090] 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%.

[0091] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] Porous base membranes may include one or more of polyethylene and polypropylene.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] In some embodiments, the pouch cell 10 further includes an electrolyte.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] In related technologies, the casing 20 is disposed outside multiple pouch battery cells 10 and is used to support the pouch battery cells 10. However, when the pouch battery cell 10 experiences thermal runaway, the casing 20 is unable to effectively dissipate heat, and the high-temperature gas flow (high-temperature gas carrying solid particles or liquid) generated during thermal runaway will impact the casing 20, making it difficult for the casing 20 to effectively block heat diffusion, which poses a safety hazard.

[0106] Based on this, this application proposes a battery device 100, in which the casing 20 has higher structural strength, more reasonable wall thickness, better heat dissipation, and better impact resistance, which can effectively block heat diffusion, reduce safety hazards, and improve the reliability of the battery device 100.

[0107] The battery device 100 and the electrical appliance 200 according to embodiments of the present invention are described below with reference to Figures 1-6.

[0108] As shown in Figure 2, this application provides a battery device 100, which may include: a housing 40 and at least one battery pack disposed in the housing 40. The battery pack may include a plurality of pouch battery cells 10 and a cover shell 20.

[0109] As shown in Figures 3 and 4, multiple pouch battery cells 10 are stacked sequentially and electrically connected; a casing 20 covers the multiple pouch battery cells 10 and is configured to constrain the multiple pouch battery cells 10 from at least three directions.

[0110] In other words, the casing 20 includes at least three plates. One plate constrains multiple pouch battery cells 10 in a first direction, while the other two plates are arranged opposite to each other and constrain multiple pouch battery cells 10 in a second direction that has an angle with the first direction. For example, one plate constrains multiple pouch battery cells 10 above or below in the height direction, and the other two plates constrain multiple pouch battery cells 10 on the left and right sides in the width direction. This achieves the constraint of multiple pouch battery cells 10 from at least three directions, improves the constraint stability and reliability of the casing 20 on the pouch battery cells 10, reduces the movement of the pouch battery cells 10, and improves the reliability and stability of the battery pack.

[0111] Furthermore, the strength of the casing 20 is made higher than the strength of the flexible outer shell 11 of the pouch battery cell 10. That is, the pouch battery cell 10 has a flexible outer shell 11, an electrode assembly 12 is disposed inside the flexible outer shell 11, and a weak part 113 can be provided on the flexible outer shell 11 so as to achieve pressure relief protection when the pouch battery cell 10 experiences thermal runaway. The strength of the casing 20 is higher than the strength of the flexible outer shell 11. When the pouch battery cell 10 experiences thermal runaway, while achieving pressure relief protection at the weak part 113, it can ensure that the casing 20 will not suffer structural damage (such as cracking, opening, etc.) under the impact of high-pressure gas flow, so as to block the high-pressure gas flow inside the casing 20.

[0112] It should be noted that the thickness of the multiple pouch cell 10 constrained by the casing 20 is less than or equal to 5.2 mm and greater than or equal to 0.2 mm.

[0113] For example, the cover shell 20 is used to constrain the plate thickness of multiple pouch battery cells 10 to be 0.2mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 5.2mm, etc.

[0114] In other words, the thickness of the shell 20 is between 0.2mm and 5.2mm. On the one hand, this avoids the shell being too thin, thus improving the impact resistance of the shell 20 and making the shell 20 better cover and protect the soft-pack battery cell 10. On the other hand, it avoids the shell being too thick, thus balancing material costs and space occupation, that is, balancing production costs and energy density.

[0115] At the same time, making the wall thickness of the casing 20 more reasonable can also improve the heat dissipation effect of the casing 20.

[0116] According to the battery device 100 of the present application embodiment, by making the strength of the covering shell 20 higher than that of the flexible shell 11 and making the thickness of the covering shell 20 more reasonable, on the one hand, the structural strength of the covering shell 20 can be improved, the probability of structural damage to the covering shell 20 after being impacted by high-pressure gas flow can be reduced, so that the heat diffusion of the soft-pack battery cell 10 is concentrated inside the covering shell 20, reducing the probability of heat diffusion outside the covering shell 20, thereby improving the reliability of the battery device 100. On the other hand, the energy density of the battery device 100 can be taken into account, and the production cost of the battery device 100 can be reduced.

[0117] According to some embodiments of this application, the cover shell 20 constrains the thickness of the plate of the plurality of pouch battery cells 10 to be less than or equal to 3 mm and greater than or equal to 0.5 mm.

[0118] Specifically, the casing 20 constrains the thickness of the multiple pouch battery cells 10 to be 0.5mm to 3mm, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, and 3mm, so that the thickness of the casing 20 does not exceed 3mm, thus taking into account the space occupied by the casing 20 and improving the energy density of the battery device 100. The thickness is not less than 0.5mm, so that the structural strength of the casing 20 can meet the usage requirements. Under the impact of high-pressure gas flow, the probability of structural damage to the casing 20 is smaller, and the heat dissipation effect of the more reasonable thickness of the casing is better, which can improve heat concentration, reduce the probability of the casing 20 melting due to heat, improve the insulation effect of the casing 20 against thermal runaway, and make the reliability of the battery device 100 higher.

[0119] According to some embodiments of this application, the cover shell 20 constrains the plate thickness of the plurality of pouch battery cells 10 to be less than or equal to 1 mm and greater than or equal to 0.6 mm.

[0120] Furthermore, the casing 20 constrains the thickness of the multiple pouch cell 10 to be 0.6mm to 1mm, such as 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1mm. On the one hand, making the thickness of the casing greater than 0.6mm ensures structural strength while also taking into account the heat dissipation effect of the casing, improving the heat concentration of the casing, thereby enhancing the isolation effect of thermal runaway and effectively delaying the spread of thermal runaway to the outside. On the other hand, making the thickness of the casing less than 1mm can reduce the material cost of the casing 20, thereby reducing production costs, and making the space occupation of the casing 20 more reasonable, while taking into account the energy density of the battery device 100.

[0121] According to some embodiments of this application, the casing 20 is an aluminum casing, and the casing 20 constrains the plate thickness of the plurality of soft-pack battery cells 10 to be less than or equal to 1 mm and greater than or equal to 0.4 mm; or the casing 20 is a stainless steel casing, and the casing 20 constrains the plate thickness of the plurality of soft-pack battery cells 10 to be less than or equal to 1 mm and greater than or equal to 0.2 mm.

[0122] Specifically, in some embodiments, the shell 20 is an aluminum shell, and the thickness of the shell 20 is in the range of 0.4mm to 1mm. In other embodiments, the shell 20 is a stainless steel shell, and the thickness of the shell 20 is in the range of 0.2mm to 1mm.

[0123] Thus, based on different materials for the shell 20, when the shell 20 is constructed of aluminum, the minimum thickness of the plate is increased to reduce the probability of structural damage caused by heat concentration in the shell 20 and improve reliability. When the shell 20 is constructed of stainless steel, the minimum thickness of the plate is decreased, which can further improve the space occupied by the shell 20.

[0124] As shown in Figures 3 and 4, according to some embodiments of this application, the casing 20 includes a first plate 21, a second plate 22 and a third plate 23 that are bent and connected in sequence. The first plate 21 and the third plate 23 form an opening on the side away from the second plate 22. The casing 20 is connected to the housing 40 of the battery device 100 through the opening. The first plate 21, the second plate 22 and the third plate 23 constrain multiple soft-pack battery cells 10 in three directions respectively.

[0125] Specifically, the first plate 21 and the third plate 23 are arranged opposite to each other, and the second plate 22 is located at one end of the same side of the first plate 21 and the third plate 23, so that the other end of the same side of the first plate 21 and the third plate 23 defines an opening. The opening is used to connect with the housing 40, that is, the end face of the first plate 21 and the third plate 23 away from the second plate 22 is connected to the housing 40. Thus, the first plate 21, the second plate 22 and the third plate 23 constrain the soft-pack battery cell 10 on two opposite surfaces and one adjacent surface, respectively. While improving the constraint effect on the battery cell, the connection between the casing 20 and the housing 40 and the connection between the soft-pack battery cell 10 and the housing 40 can be located on the same side, which can also reduce the assembly difficulty and improve the assembly efficiency.

[0126] It is understandable that the thickness of the first plate 21 and the third plate 23 meets the above-mentioned size range, which can take into account the space occupied by the battery pack in the direction of the first plate 21 and the third plate 23, while the thickness of the second plate 22 meets the above-mentioned size range, which can take into account the space occupied by the battery pack in the direction of the second plate 22.

[0127] As shown in Figure 4, according to some embodiments of this application, the first plate 21 and the third plate 23 constrain the multiple pouch cell 10 in opposite directions.

[0128] Specifically, the first plate 21 and the third plate 23 are arranged opposite to each other. By constraining the soft-pack battery cell 10 in opposite directions through the first plate 21 and the third plate 23 arranged opposite to each other, the movement of the soft-pack battery cell 10 can be reduced, and the stability and reliability of the battery pack in the housing 40 can be improved.

[0129] For example, the first plate 21 and the third plate 23 can constrain and limit the soft-pack battery cell 10 in the width direction. The width direction of the soft-pack battery cell 10 can correspond to the width direction or length direction of the battery device 100. This can limit the soft-pack battery cell 10 in the width or length direction of the battery device 100, thereby reducing the movement of the battery pack relative to the housing 40 in the width or length direction of the battery device 100 and improving the stability and reliability of the battery device 100.

[0130] Referring to Figures 4 and 5, according to some embodiments of this application, the direction in which the second plate 22 constrains the plurality of pouch cell 10 is perpendicular to the direction in which the first plate 21 or the third plate 23 constrains the plurality of pouch cell 10.

[0131] The second plate 22 is connected to the first plate 21 and the third plate 23 on both sides of the first direction to define an opening in the second direction. The surface of the soft-pack battery cell 10 located on one side of the opening can be connected to the housing 40. The first direction is perpendicular to the second direction. While the first plate 21 and the third plate 23 limit the soft-pack battery cell 10 on both sides of the first direction, the second plate 22 can limit the soft-pack battery cell 10 at one end of the first direction.

[0132] For example, the second plate 22 can constrain and limit the soft-pack battery cell 10 in the height direction of the soft-pack battery cell 10, so as to reduce the jump of the battery pack relative to the housing 40 in the height direction of the battery device 100 and improve the stability and reliability of the battery device 100.

[0133] As shown in Figure 5, according to some embodiments of this application, the first plate 21, the second plate 22 and the third plate 23 respectively form two openings on both sides in the third direction, and each opening is provided with a busbar 30 for merging multiple soft-pack battery cells 10, and each busbar 30 covers the corresponding opening.

[0134] Specifically, the first plate 21 and the third plate 23 are arranged opposite each other in the first direction, and the second plate 22 is located at the same end of the first plate 21 and the third plate 23 in the second direction. The first plate 21, the second plate 22 and the third plate 23 define two openings on both sides in the third direction, and the two busbars 30 are respectively arranged on the two openings. This can isolate the space defined by the shell 20 for accommodating the soft-pack battery cell 10 from the outside. In addition, by setting the structural strength and thickness of the shell, the isolation effect of thermal runaway can be improved, and the propagation speed of thermal runaway can be effectively reduced.

[0135] It should be noted that the first direction is the width direction of the soft-pack battery cell 10, the second direction is the height direction of the soft-pack battery cell 10, and the third direction is the length direction of the soft-pack battery cell 10.

[0136] As shown in Figure 2, the battery device 100 includes a housing 40 and a battery pack. The battery pack is at least one and includes at least one soft-pack battery cell 10 as described in the above embodiment and a casing 20. At least one side surface of the casing 20 has a pressure relief portion 221.

[0137] The housing 40 has an accommodating space, and one or more battery packs are disposed in the accommodating space. Each battery pack has one or more pouch battery cells 10 disposed inside the casing 20, and the pouch battery cells 10 are constructed as described above using the flexible casing 11.

[0138] As shown in Figures 4 and 6, according to some embodiments of this application, the flexible shell 11 has a side surface 111 opposite to the large surface of the electrode assembly 12 and a circumferential surface 112 avoiding the large surface. The side surface 111 and / or the circumferential surface 112 are provided with a weak portion 113, and the covering shell 20 has a pressure relief portion 221 that is at least partially opposite to the weak portion 113.

[0139] The casing 20 is used to cover at least one of the more than a dozen circumferential surfaces 112 and two side surfaces 111 of the pouch battery cell 10. A weak portion 113 is provided on at least one circumferential surface 112 of the pouch battery cell 10. At least one side of the casing 20 forms a pressure relief portion 221, such as the pressure relief portion 221 being opposite to the weak portion 113, or the pressure relief portion 221 being located on a first surface of the casing 20, while the weak portion 113 is opposite to a second surface of the casing 20, and the first surface and the second surface are adjacent.

[0140] In this way, by providing a pressure relief section 221 on the casing 20 that cooperates with the weak section 113, when the soft-pack battery cell 10 experiences thermal runaway, the high-temperature gas flow discharged through the weak section 113 can be further released outward through the pressure relief section 221. By cooperating with the weak section 113 and the pressure relief section 221, the high-temperature gas flow can be directionally discharged, thereby improving the reliability of the battery device 100.

[0141] As shown in Figure 6, according to some embodiments of this application, the second plate 22 is opposite to the side 111, and the projected outline area of ​​the second plate 22 toward the side 111 of the flexible shell 11 is less than or equal to the area of ​​the side 111.

[0142] Specifically, the circumferential surface 112 is defined as including a first surface and a second surface opposite to it. The first surface is opposite to the first plate 21, and the second surface is disposed away from the first plate 21. The second surface is used to connect to the housing 40. The two sides of the first and second surfaces are the two side surfaces 111 of the soft-pack battery cell 10, and the two ends of the first and second surfaces are the other two circumferential surfaces 112 of the soft-pack battery cell 10. The second plate 22 is opposite to the side surfaces 111, so as to limit the soft-pack battery cell 10 in the direction of the second plate 22. The area of ​​the surface of the second plate 22 opposite to the side surfaces 111 can be less than or equal to the area of ​​the side surfaces 111.

[0143] In other words, in some embodiments, the size of the second plate 22 is the same as the size of the side 111, while in other embodiments, the size of the second plate 22 is smaller than the size of the side 111. On the one hand, this can avoid the second plate 22 being too large, which would prevent the second side from being connected to the housing 40, thus improving the stability and reliability of the battery pack within the housing 40. On the other hand, the second plate 22 can use less material, which can also reduce the material cost of the battery pack and the battery device 100.

[0144] According to some embodiments of this application, the battery device 100 further includes: a housing 40, wherein the side end faces of the first plate 21 and the third plate 23 away from the second plate 22 are connected to the housing 40 through an adhesive layer 42.

[0145] Specifically, the housing 40 has a base plate 41, which is connected to the bottom surface (i.e. the second surface) of the soft-pack battery cell 10, the second plate 22 and the side end face of the third plate 23 facing the base plate 41 by an adhesive layer 42 to improve the fixing stability and reliability of the battery pack.

[0146] As shown in Figure 5, according to some embodiments of this application, the base plate 41 includes a cold plate, and the adhesive layer 42 is located between the cold plate and a plurality of soft-pack battery cells 10.

[0147] In some embodiments, the bottom plate 41 of the housing 40 is formed as a cold plate, and the cold plate is connected to the soft-pack battery cell 10 through an adhesive layer 42. In other embodiments, a cold plate is provided between the bottom plate 41 and the soft-pack battery cell 10, and the cold plate is connected to the soft-pack battery cell 10 through an adhesive layer 42.

[0148] In other words, the adhesive layer 42 is constructed as a structural adhesive, and the base plate 41 with the cold plate is connected to the soft-pack battery cell 10. Under the premise of ensuring that the battery pack is stably and reliably fixed in the housing 40, the temperature of the battery pack can also be regulated by the cold plate, so that the battery pack can work at a suitable temperature. This can improve the working stability and reliability of the battery pack, reduce the probability of the battery pack overheating, reduce the probability of thermal runaway of the battery pack, and thus improve the reliability of the battery pack and even the battery device 100.

[0149] As shown in FIG5, according to some embodiments of the present application, the adhesive layer 42 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 pouch battery cells 10, and is located between adjacent pouch battery cells 10, and / or between pouch battery cells 10 and the first plate 21, and / or between pouch battery cells 10 and the third plate 23.

[0150] In other words, when the structural adhesive is used to connect and fix the soft-pack battery cell 10 to the cold plate, at least part of the adhesive layer 42 overflows between adjacent soft-pack battery cells 10, and / or between the soft-pack battery cell 10 and the first plate 21, and / or between the soft-pack battery cell 10 and the third plate 23, forming an overflow portion 422. By setting the overflow portion 422, not only can the area between the adhesive layer 42 and the soft-pack battery cell 10, the adhesive layer 42 and the first plate 21, and the second plate 22 be increased to improve the fixing stability and reliability of the battery pack on the housing 40, but the overflow portion 422 can also fill the gaps between adjacent soft-pack battery cells 10 and between the soft-pack battery cell 10 and the second plate 22 to limit the soft-pack battery cell 10 and the housing 20, reduce the movement of the battery pack in the housing 40, and reduce the movement of the soft-pack battery cell 10 in the housing 20.

[0151] The second plate 22 has a first plate 21 and a third plate 23 on its two sides respectively. The second plate 22 of the cover shell 20 can be opposite to a circumferential surface 112 of the soft-pack battery cell 10, while the first plate 21 and the third plate 23 can be opposite to the two side surfaces 111 of the soft-pack battery cell 10 respectively. The weak part 113 formed on the circumferential surface 112 can be at least partially opposite to the pressure relief part 221 formed on the second plate 22 (i.e., the pressure relief part 221 is formed on the second plate 22).

[0152] It should be noted that the weak part 113 and the pressure relief part 221 are at least partially opposite to each other, meaning that the weak part 113 formed on the circumferential surface 112 projects toward the first plate 21 and the projected outline at least partially overlaps with the outline of the pressure relief part 221.

[0153] In this way, on the one hand, the gas and fire generated after thermal runaway of the pouch cell 10 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 weak part 113 and the pressure relief part 221 is shorter, which can achieve rapid discharge while the gas and fire flow stays inside the casing 20 for a shorter time, thus having less impact on other pouch cells 10 around the thermally runaway pouch cell 10. It can also further reduce the spread rate of thermal runaway and improve the reliability of the battery pack and battery device 100.

[0154] As shown in Figures 4 and 5, according to some embodiments of this application, the second plate 22 is spaced apart from the side of the circumferential surface 112 that has the pressure relief portion 221 to define the exhaust passage a.

[0155] In this way, the high-temperature gas flow generated after the weak part 113 ruptures can be released to the exhaust channel a first, and after being initially buffered by the exhaust channel a, it can be discharged through the pressure relief part 221. This can reduce the pressure of the high-temperature gas flow after it flows out of the pressure relief part 221, thereby reducing the impact and damage after the thermal runaway of the soft-pack battery cell 10.

[0156] According to some embodiments of this application, the second plate 22 is constructed as a flat plate or an arc plate.

[0157] That is, in some embodiments, the second plate 22 is constructed as a flat plate, while in other embodiments, the second plate 22 is constructed as an arc-shaped plate.

[0158] According to some embodiments of this application, there are multiple pressure relief sections 221, which are spaced apart in the length direction and / or width direction of the second plate 22.

[0159] Therefore, each of the multiple weak points 113 on each pouch cell 10 can have a corresponding pressure relief part 221, so that the high-temperature gas flow buffered by the exhaust channel a can be directly discharged through the corresponding pressure relief part 221, thereby increasing the discharge speed and reducing the residence time of the high-temperature gas flow in the exhaust channel a during the discharge process, thereby reducing the spread speed of thermal runaway between adjacent pouch cells 10 in the battery pack and improving the reliability of the battery pack.

[0160] According to some embodiments of this application, the total charge of the plurality of soft-pack battery cells 10 within a single casing 20 is less than 0.9 kWh, and the energy density of the plurality of soft-pack battery cells 10 within a single casing 20 satisfies: L≤450Wh / L.

[0161] Thus, in embodiments where the total charge within a single casing 20 is less than 0.9 kWh, the energy density of the multiple pouch battery cells 10 within a single casing 20 should be less than or equal to 450 Wh / L. This can improve reliability, reduce the rate of thermal runaway propagation between adjacent casings 20, and allow for a more reasonable number of pouch battery cells 10 within the casing 20, while also taking into account space requirements.

[0162] According to some embodiments of this application, the total charge of the plurality of soft-pack battery cells 10 within a single casing 20 is less than 0.72 kWh, and the energy density of the plurality of soft-pack battery cells 10 within a single casing 20 satisfies: 450 Wh / L < L ≤ 600 Wh / L.

[0163] Thus, in embodiments where the total charge within a single casing 20 is less than 0.72 kWh, the energy density of the multiple pouch battery cells 10 within a single casing 20 should be greater than 450 Wh / L and less than or equal to 600 Wh / L. This can improve reliability, reduce the rate of thermal runaway propagation between adjacent casings 20, and allow for a more reasonable number of pouch battery cells 10 within the casing 20, while also taking into account space requirements.

[0164] According to some embodiments of this application, the total charge of the plurality of soft-pack battery cells 10 within a single casing 20 is less than 0.6 kWh, and the energy density of the plurality of soft-pack battery cells 10 within a single casing 20 satisfies: 600 Wh / L < L ≤ 700 Wh / L.

[0165] In embodiments where the total charge within a single casing 20 is less than 0.6 kWh, the energy density of the multiple pouch battery cells 10 within a single casing 20 should be greater than 600 Wh / L and less than or equal to 700 Wh / L. This can improve reliability, reduce the rate of thermal runaway propagation between adjacent casings 20, and allow for a more reasonable number of pouch battery cells 10 within the casing 20, while also taking into account space requirements.

[0166] According to some embodiments of this application, the total charge of the plurality of pouch battery cells 10 within a single casing 20 is less than 0.48 kWh, and the energy density of the plurality of pouch battery cells 10 within a single casing 20 satisfies L > 700 Wh / L.

[0167] Thus, in embodiments where the total charge within a single casing 20 is less than 0.48 kWh, the energy density of the multiple pouch battery cells 10 within a single casing 20 should be greater than 700 Wh / L. This can improve reliability, reduce the rate of thermal runaway propagation between adjacent casings 20, and allow for a more reasonable number of pouch battery cells 10 within the casing 20, while also taking into account space requirements.

[0168] It should be noted that the test conditions in this application embodiment are as follows: two adjacent battery packs are set in a sealed space of a simulated battery device. One battery pack experiences thermal runaway (e.g., thermal runaway is triggered by short-circuiting), while the other battery pack is in a normal state. The casing 20 of both battery packs is used to constrain the thickness of the pouch cell 10 to be the same (minimum value of 0.2mm). The total capacity of the multiple pouch cells 10 in the two battery packs is the same. Based on national standards, a threshold for the allowable duration of thermal runaway of one battery pack leading to thermal runaway of the other battery pack is set (e.g., GB). The national standard 38031 requires that the battery device 100 should not catch fire within five minutes after the thermal runaway of a single battery cell. Based on this, an allowable time threshold of 5 minutes can be set. Then, it can be determined whether the time taken for thermal runaway to occur in the battery pack 10 under normal conditions has reached or exceeded the allowable time threshold between adjacent battery packs 10. Reaching or exceeding the allowable time threshold is defined as no spread. This determines the energy density limit of the pouch battery cell in the battery pack under the given total charge. The total charge can be further adjusted to determine the corresponding energy density limit under different total charge conditions. This also determines the relationship between the total charge of multiple pouch battery cells 10 in a single casing 20 and the energy density of the pouch battery cell 10.

[0169] In an exemplary embodiment where the length of the pouch cell 10 is 355mm, the width is 13.8mm, and the height is 123mm, and the thickness of the plate constraining the multiple pouch cell 10 by the casing 20 is 0.2mm, the thermal diffusion under the same energy density but different internal charge is as follows:

[0170] In summary, this application sets the energy density of each pouch cell 10 based on the total capacity of the multiple pouch cells 10 within each battery pack. For example, when the energy density is less than or equal to 450Wh / L, the total capacity should be less than 0.9 kWh; when the energy density is in the range of 450Wh / L < L ≤ 600Wh / L, the total capacity should be less than 0.72 kWh; when the energy density is in the range of 600Wh / L < L ≤ 700Wh / L, the total capacity should be less than 0.6 kWh; and when the energy density is greater than 700Wh / L, the total capacity should be less than 0.48 kWh.

[0171] Therefore, based on the table above, it can be seen that by reasonably setting the relationship between total energy capacity and energy density, the thermal runaway suppression effect when the soft-pack battery cell 10 in the battery pack experiences thermal runaway can be improved, the propagation speed of thermal runaway can be reduced, and the reliability can be improved.

[0172] As shown in the accompanying drawings, the soft-pack battery cell 10 of this embodiment is constructed as a soft-pack battery cell 10, the electrode assembly 12 is disposed inside the flexible shell 11, the flexible shell 11 has a weak portion 113 formed on at least the circumferential surface 112, the battery pack includes at least one soft-pack battery cell 10 of this embodiment, and the pressure relief portion 221 on the first plate 21 of the casing 20 is at least partially opposite to the weak portion 113, the second plate 22 is opposite to the side 111 of the flexible shell 11, the bottom plate 41 of the housing 40 is constructed as a cold plate, or a cold plate is disposed on the top of the bottom plate 41, the cold plate is connected to the soft-pack battery cell 10 through an adhesive layer 42, the overflow portion 422 of the adhesive layer 42 overflows between adjacent soft-pack battery cells 10, and / or between the soft-pack battery cell 10 and the second plate 22.

[0173] According to some embodiments of this application, the soft-pack battery cell 10 is any one of a lithium iron phosphate battery cell, a ternary lithium battery cell, and a solid-state battery cell.

[0174] In other words, in some embodiments, the pouch battery cell 10 is constructed as a lithium iron phosphate battery, in some embodiments, the pouch battery cell 10 is constructed as a ternary lithium battery cell, and in some embodiments, the pouch battery cell 10 is constructed as a solid-state battery cell.

[0175] Solid-state battery cells can be, but are not limited to, polymer solid-state battery cells, oxide solid-state battery cells, sulfide solid-state battery cells, halide solid-state battery cells, etc. Solid-state battery cells can also be semi-solid-state battery cells or all-solid-state battery cells.

[0176] In the above technical solutions, in the embodiments of this application that are constructed as lithium iron phosphate battery cells, the reliability of the pouch battery cells can be improved and the cycle life of the pouch battery cells can be extended. In the embodiments of this application that are constructed as ternary lithium battery cells, the energy density of the pouch battery cells can be improved and the driving range can be increased. In the embodiments of this application that are constructed as solid-state pouch battery cells, not only the energy density can be improved, but also the reliability can be improved.

[0177] According to some embodiments of this application, when the pouch cell 10 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 pouch cell 10 is 96:1-3:1-3; when the pouch cell 10 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 pouch cell 10 is 96:2-3:1-2.

[0178] It is understandable that when the pouch cell 10 is a lithium iron phosphate battery cell, the positive electrode material of the pouch cell 10 has the following proportions: the positive electrode active material accounts for 96 parts of the total weight of the positive electrode material; the binder accounts for 1 to 3 parts of the total weight of the positive electrode material (for example, it may include but is not limited to 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc.); and the conductive agent accounts for 1 to 3 parts of the total weight of the positive electrode material (for example, it may include but is not limited to 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc.).

[0179] For example, when the pouch cell 10 is a lithium iron phosphate battery cell, the positive electrode active material is LFP (which can refer to LiFePO4, i.e., lithium iron phosphate), the binder can be PVDF (polyvinylidene fluoride), and the conductive agent can be conductive carbon black. The ratio of LFP:PVDF:conductive carbon black can be 96:2:2, meaning that the total weight of the positive electrode active material is divided into 100 parts, with LFP accounting for 96 parts, PVDF accounting for 2 parts, and conductive carbon black also accounting for 2 parts. The weight unit of the positive electrode active material can be grams.

[0180] When the pouch cell 10 is a ternary lithium battery cell, in the positive electrode material of the pouch cell 10, the positive electrode active material accounts for 96 parts of the total weight of the positive electrode material, the binder accounts for 2 to 3 parts of the total weight of the positive electrode material (for example, including but not limited to 2, 2.2, 2.5, 2.8, 3, etc.), and the conductive agent accounts for 1 to 2 parts of the total weight of the positive electrode material (for example, including but not limited to 1, 1.2, 1.5, 1.8, 2, etc.). The ternary lithium battery cell can be, but is not limited to, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, etc.

[0181] For example, the ternary material of the ternary battery cell can be an octet LiNi. 0.8 Co 0.1 Mn 0.1 The weight ratio of O2, positive electrode active material, binder, and conductive agent is 96:2.5:1.5, meaning the total weight of the positive electrode material is divided into 100 parts. (This refers to the octet LiNi...) 0.8 Co 0.1 Mn 0.1 The composition of O2 is 96 parts, the composition of adhesive is 2.5 parts, and the composition of conductive agent is 1.5 parts.

[0182] In the above technical solutions, when the pouch battery cell 10 is a lithium iron phosphate battery cell, a high proportion of positive electrode active material means that more substances capable of electrochemical reactions can be accommodated within a limited electrode assembly. This is beneficial for increasing the capacity and energy density of the battery device 100, enabling the lithium iron phosphate battery cell to output higher power while maintaining a relatively small volume and weight, meeting the application scenarios with certain energy density requirements. Using the above-mentioned range for the amount of binder and conductive agent can reduce the cost of auxiliary materials, thereby reducing the overall cost of the battery device 100. When the pouch battery cell 10 is a ternary battery cell, due to the relatively complex structure and surface properties of ternary materials, using the above-mentioned proportions of positive electrode active material, binder, and conductive agent helps to ensure good adhesion between positive electrode active material particles and between the active material and the current collector, thereby improving the mechanical stability and integrity of the electrode assembly. This helps to reduce the risk of active material detachment and electrode pulverization during charging and discharging, and extends the cycle life of the battery device 100.

[0183] As shown in Figure 1, this application proposes an electrical device 200, including: the battery device 100 in the above embodiment.

[0184] Furthermore, as shown in Figure 1, the electrical equipment 200 can be a vehicle, and the battery device 100 can be integrated on the vehicle chassis. That is, the vehicle body structure is a split body, with the upper body and the integrated intelligent chassis assembled together, and the battery device 100 forming part of the integrated intelligent chassis. In this way, the top plate of the box 40 can also participate in defining the vehicle floor, which can save the meaningless stacking of multiple layers of sheet metal, reduce material costs, and make the space occupation of the chassis more reasonable. The space inside the chassis for accommodating the battery device 100 is larger and the energy density is higher.

[0185] It is understandable that the electrical equipment 200 is constructed as a vehicle, that is, the vehicle uses the aforementioned battery device 100. The battery device 100 has higher energy density and higher reliability, which can improve the vehicle's driving range and driving safety.

[0186] Other configurations and operations of the soft-pack battery cell 10, battery device 100, and electrical equipment 200 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0187] 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.

[0188] 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 device (100), wherein, include: Multiple soft-pack battery cells (10) are stacked sequentially and electrically connected; A casing (20) is provided, which covers the plurality of pouch cell units (10) and is configured to constrain the plurality of pouch cell units (10) from at least three directions; the strength of the casing (20) is higher than the strength of the flexible outer shell (11) of the pouch cell unit (10). The encapsulation shell (20) constrains the thickness of the multiple soft-pack battery cells (10) to be less than or equal to 5.2 mm and greater than or equal to 0.2 mm.

2. The battery device (100) according to claim 1, wherein, The encapsulation shell (20) constrains the thickness of the multiple soft-pack battery cells (10) to be less than or equal to 3 mm and greater than or equal to 0.5 mm.

3. The battery device (100) according to claim 1, wherein, The encapsulation shell (20) constrains the thickness of the multiple soft-pack battery cells (10) to be less than or equal to 1 mm and greater than or equal to 0.6 mm.

4. The battery device (100) according to claim 1, wherein, The casing (20) is an aluminum casing, and the casing (20) constrains the thickness of the multiple soft-pack battery cells (10) to be less than or equal to 1 mm and greater than or equal to 0.4 mm. or, The casing (20) is a stainless steel casing, and the casing (20) constrains the thickness of the plate of the plurality of soft-pack battery cells (10) to be less than or equal to 1 mm and greater than or equal to 0.2 mm.

5. The battery device (100) according to any one of claims 1-4, wherein, The casing (20) includes a first plate (21), a second plate (22) and a third plate (23) that are bent and connected in sequence. The first plate (21) and the third plate (23) form an opening on the side away from the second plate (22). The casing (20) is connected to the housing (40) of the battery device (100) through the opening. The first plate (21), the second plate (22) and the third plate (23) constrain the plurality of pouch cell units (10) in three directions respectively.

6. The battery device (100) according to claim 5, wherein, The first plate (21) and the third plate (23) constrain the plurality of pouch cell units (10) in opposite directions.

7. The battery device (100) according to claim 6, wherein, The second plate (22) constrains the direction of the plurality of pouch battery cells (10) perpendicular to the direction of the first plate (21) or the third plate (23) constrains the plurality of pouch battery cells (10).

8. The battery device (100) according to any one of claims 5-7, wherein, The first plate (21), the second plate (22) and the third plate (23) each form two openings on two sides in the third direction. Each opening is provided with a busbar (30) for merging multiple soft-pack battery cells (10). Each busbar (30) covers the corresponding opening.

9. The battery device (100) according to any one of claims 5-8, wherein, The battery device (100) further includes a housing (40), wherein the end faces of the first plate (21) and the third plate (23) away from the second plate (22) are connected to the housing (40) through an adhesive layer (42).

10. The battery device (100) according to claim 9, wherein, The box (40) has a bottom plate (41), which is connected to the first plate (21) and the third plate (23) through the adhesive layer (42).

11. The battery device (100) according to claim 10, wherein, The base plate (41) is constructed as a cold plate, and / or the base plate (41) is provided with a cold plate on the side facing the plurality of soft-pack battery cells (10), and the adhesive layer (42) is located between the cold plate and the plurality of soft-pack battery cells (10).

12. The battery device (100) according to claim 10, wherein, The adhesive layer (42) 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 pouch battery cells (10), and is located between adjacent pouch battery cells (10), and / or between the pouch battery cells (10) and the first plate (21), and / or between the pouch battery cells (10) and the third plate (23).

13. The battery device (100) according to any one of claims 5-12, wherein, The flexible outer shell (11) has a side surface (111) opposite to the large surface of the electrode assembly (12) and a circumferential surface (112) avoiding the large surface, the side surface (111) and / or the circumferential surface (112) being provided with a weak portion (113), and the covering shell (20) having a pressure relief portion (221) at least partially opposite to the weak portion (113).

14. The battery device (100) according to claim 13, wherein, The pressure relief section (221) is formed on the second plate (22).

15. The battery device (100) according to claim 14, wherein, The second plate (22) is spaced apart from the side of the circumferential surface (112) having the pressure relief portion (221) to define an exhaust passage (a).

16. The battery device (100) according to claim 15, wherein, The second plate (22) is constructed as a flat plate or an arc plate.

17. The battery device (100) according to claim 15, wherein, There are multiple pressure relief sections (221), and the multiple pressure relief sections (221) are spaced apart in the length direction and / or width direction of the second plate (22).

18. The battery device according to any one of claims 1 to 17, characterized in that, The total charge of the plurality of pouch battery cells (10) within a single encapsulation shell (20) is less than 0.9 kWh, and the energy density of the plurality of pouch battery cells (10) within a single encapsulation shell (20) satisfies: L≤450Wh / L.

19. The battery device according to any one of claims 1 to 17, characterized in that, The total charge of the plurality of pouch battery cells (10) within a single casing (20) is less than 0.72 kWh, and the energy density of the plurality of pouch battery cells (10) within a single casing (20) satisfies: 450 Wh / L < L ≤ 600 Wh / L.

20. The battery device according to any one of claims 1 to 17, characterized in that, The total charge of the plurality of soft-pack battery cells (10) within a single casing (20) is less than 0.6 kWh, and the energy density of the plurality of soft-pack battery cells (10) within a single casing (20) satisfies: 600 Wh / L < L ≤ 700 Wh / L.

21. The battery device according to any one of claims 1 to 17, characterized in that, The total charge of the plurality of pouch battery cells (10) within a single encapsulation shell (20) is less than 0.48 kWh, and the energy density of the plurality of pouch battery cells (10) within a single encapsulation shell (20) satisfies L > 700 Wh / L.

22. The battery device according to any one of claims 1 to 17, wherein, The soft-pack battery cell (10) is any one of lithium iron phosphate battery cell, ternary lithium battery cell, and solid-state battery cell.

23. The battery device according to claim 22, wherein, When the pouch battery cell (10) 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 pouch battery cell (10) is 96:1-3:1-3; when the pouch battery cell (10) 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 pouch battery cell (10) is 96:2-3:1-2.

24. An electrical appliance, wherein, include: The battery device according to any one of claims 1-23.

25. The electrical equipment according to claim 24, wherein, The electrical equipment in question is a vehicle.

26. The electrical equipment according to claim 25, wherein, The battery device is integrated into the chassis of the vehicle, and the top plate of the housing (40) participates in defining the vehicle floor.

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