Battery and electric equipment

Abstract

The utility model discloses a battery and electric equipment, and the battery comprises a first shell which is provided with a first cavity; the second shell is provided with a second cavity, the first shell is arranged in the second cavity, the peripheral surface of the first shell is welded with the cavity wall of the second cavity, and the first cavity is communicated with the second cavity to form a storage cavity; and the battery cell is arranged in the storage cavity. The battery provided by the utility model can have relatively high energy density.

Description

Technical Field

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

[0002] In related technologies, the battery casing includes an aluminum-plastic film and a metal shell. The metal shell comprises a cover plate and a metal casing, formed using a stamping process. After stamping, the metal shell forms a body and a protrusion. The body has a storage cavity, and the protrusion surrounds the edge of the body and protrudes relative to it. The cover plate and the protrusion of the metal shell are welded together to seal the storage cavity. Due to the presence of the protrusion, the aforementioned metal shell, with a fixed size, occupies excessive space, resulting in a lower energy density for the battery. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a battery capable of having a high energy density.

[0004] This utility model also proposes an electrical device.

[0005] The battery according to a first aspect embodiment of the present invention includes:

[0006] The first shell has a first cavity;

[0007] The second shell has a second cavity, and the first shell is disposed in the second cavity. The outer peripheral surface of the first shell is welded to the cavity wall of the second cavity. The first cavity and the second cavity are connected to form a storage cavity.

[0008] The battery cell is disposed in the storage cavity.

[0009] The battery according to the present invention has at least the following beneficial effects: the first shell is disposed in the second cavity, and the outer peripheral surface of the first shell and the cavity wall of the second cavity are welded together. In the prior art, when the cover plate and the metal shell are connected, the cover plate is connected to the protrusion of the metal shell, which leads to a low energy density of the battery. In this application, the connection between the first shell and the second shell is mainly achieved by disposing the first shell in the second cavity and welding the outer peripheral surface of the first shell and the cavity wall of the second cavity. This eliminates the need for the protrusion to achieve the welding of the two shells, thus enabling the battery to have a higher energy density.

[0010] According to some embodiments of the present invention, the battery further includes a flattening component, the cavity wall of the second cavity includes a first wall and a second wall, the first wall surrounds the edge connected to the second wall, the first wall includes a first part and a second part, the first part is welded to the first shell, the flattening component is connected to the second part, and the flattening component is flush with the cavity wall of the first cavity.

[0011] According to some embodiments of the present invention, the flat member surrounds at least a portion of the battery cell.

[0012] According to some embodiments of the present invention, the flattened part is coated on the second part of the battery.

[0013] According to some embodiments of the present invention, the flat component is bonded to the second part.

[0014] According to some embodiments of the present invention, the battery has the following dimensions: along the thickness direction of the first shell, the size of the first part is A, the size of the second cavity is C, the size of the flat part is D, and CA-1mm≤D≤CA.

[0015] According to some embodiments of the present invention, the battery of the second cavity includes a first wall and a second wall. The first wall surrounds the edge connected to the second wall. The first wall includes a first part and a second part. The first part is welded to the first shell. Along the thickness direction of the first shell, the size of the first part is A, and the size of the storage cavity is B, where 0.2mm≤A≤0.5B.

[0016] According to some embodiments of the present invention, the size of the second cavity in the battery is C, where A+2mm≤C≤0.9B+A.

[0017] According to some embodiments of the present invention, the battery further includes a terminal post, the battery cell is electrically connected to the terminal post, the terminal post is insulatedly connected to the second shell, and the terminal post protrudes relative to the second shell.

[0018] The electrical device according to the second aspect of the present invention includes the battery described in any one of the first aspect embodiments.

[0019] The electrical device according to the embodiments of this utility model has at least the following beneficial effects: A first shell is disposed in a second cavity, and the outer peripheral surface of the first shell is welded to the cavity wall of the second cavity. In the prior art, when the cover plate and the metal shell are connected, the cover plate is connected to a protrusion of the metal shell, which results in a lower energy density of the battery. However, in this application, the connection between the first shell and the second shell is mainly achieved by disposing the first shell in the second cavity and welding the outer peripheral surface of the first shell to the cavity wall of the second cavity. This eliminates the need for a protrusion to weld the two shells, thus enabling the battery to have a higher energy density. Furthermore, the electrical device with this battery has better battery life.

[0020] Additional aspects and advantages of this invention 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 the invention. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 This is a schematic diagram of a battery according to the first embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of a battery according to the second embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the battery according to the third embodiment of the present invention.

[0025] Figure label:

[0026] Battery 10, first shell 100, first cavity 110, second shell 200, second cavity 210, first wall 211, first part 212, second part 213, second wall 214, storage cavity 300, battery cell 400, flat part 500, terminal post 600. Detailed Implementation

[0027] The embodiments of this utility model 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 utility model, and should not be construed as limiting this utility model.

[0028] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model.

[0029] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0031] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. 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.

[0032] The battery 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.

[0033] A battery typically consists of a cell. The cell includes a positive electrode, a negative electrode, and a separator. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0034] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0035] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0036] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0037] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate 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 iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al0.05 At least one of O2 and its modified compounds.

[0038] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0039] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0040] 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 electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0041] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0042] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0043] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0044] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0045] In some implementations, the battery cell also includes an isolation element disposed between the positive and negative terminals.

[0046] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0047] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0048] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0049] In some embodiments, the battery also includes an electrolyte that acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0050] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0051] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0052] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0053] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0054] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0055] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0056] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0057] In some implementations, the battery cell has a wound structure. The positive and negative electrode plates are wound into a wound structure.

[0058] In some implementations, the battery cell has a laminated structure.

[0059] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0060] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0061] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0062] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0063] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0064] In some implementations, the battery cell can be cylindrical, flat, or polygonal, etc.

[0065] In some implementations, the battery cell is provided with tabs that allow current to be drawn out of the cell. The tabs include a positive tab and a negative tab.

[0066] In some embodiments, the battery may include a casing. The casing is used to encapsulate components such as the battery cell and electrolyte. The casing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0067] As an example, the battery can be a cylindrical battery, a prismatic battery, a pouch battery, or a battery of other shapes. Prismatic batteries include, but are not limited to, square-shell batteries, blade-shaped batteries, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0068] The battery mentioned in the embodiments of this application refers to a single physical module that includes one or more batteries to provide higher voltage and capacity.

[0069] In some embodiments, the battery can be a battery module, and when there are multiple batteries, the multiple batteries are arranged and fixed to form a battery module.

[0070] In some embodiments, the battery may be a battery pack, which includes a housing and a battery, with the battery or battery module housed within the housing.

[0071] 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.

[0072] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0073] In related technologies, the battery casing includes an aluminum-plastic film and a metal shell. The metal shell comprises a cover plate and a metal casing, formed by stamping. After stamping, the metal shell forms a body and a protrusion. The body has a storage cavity, and the protrusion surrounds the edge of the body and protrudes relative to it. The cover plate and the protrusion of the metal shell are welded together to seal the storage cavity. Due to the presence of the protrusion, the aforementioned metal shell occupies excessive space within a fixed size, resulting in a lower energy density of the battery. Therefore, this application proposes a battery.

[0074] Please refer to Figures 1 to 3In some embodiments, the battery 10 includes a first shell 100, a second shell 200, and a battery cell 400. The first shell 100 has a first cavity 110. The shape of the first shell 100 can be a cuboid or a cube, and the shape of the first cavity 110 can also be a cuboid or a cube. The material of the first shell 100 can be a metal, such as iron or stainless steel. The second shell 200 has a second cavity 210. The shape of the second shell 200 can also be a cuboid or a cube, and the shape of the second cavity 210 can also be a cuboid or a cube. The material of the second shell 200 can also be a metal, such as iron or stainless steel. The first shell 100 is disposed within the second cavity 210. That is, the volume of the first shell 100 is smaller than the volume of the second shell 200, and the second shell 200 can be fitted onto the outer peripheral surface of the first shell 100. The outer peripheral surface of the first shell 100 and the cavity wall of the second cavity 210 are welded together. The first cavity 110 and the second cavity 210 are connected to form a storage cavity 300. The battery cell 400 is disposed in the storage cavity 300. Specifically, the first shell 100 is disposed in the second cavity 210, and the outer peripheral surface of the first shell 100 is welded to the cavity wall of the second cavity 210. In the prior art, when the cover plate and the metal shell are connected, the cover plate is connected to the protrusion of the metal shell, which results in a low energy density of the battery 10. In this application, the connection between the first shell 100 and the second shell 200 is mainly achieved by disposing of the first shell 100 in the second cavity 210 and welding the outer peripheral surface of the first shell 100 to the cavity wall of the second cavity 210. This eliminates the need for a protrusion to weld the two shells, thus enabling the battery 10 to have a higher energy density.

[0075] Furthermore, the thickness of the first shell 100 and the second shell 200 is relatively small, ranging from 25µm to 250µm. For example, the thicknesses of the first shell 100 and the second shell 200 can be 25µm, 50µm, 75µm, 100µm, or 250µm. In this application, when the thickness of the first shell 100 and the second shell 200 is relatively thin, directly stamping the storage cavity 300 onto the first shell 100 might cause damage to the first shell 100. Therefore, a method can be adopted where the first shell 100 has a first cavity 110 and the second shell 200 has a second cavity 210, and then the first cavity 110 and the second cavity 210 are connected. This effectively avoids damage to the first shell 100 and the second shell 200 and gives the storage cavity 300 a greater depth. Additionally, it should be noted that the thicknesses of the first shell 100 and the second shell 200 can be the same or different.

[0076] Furthermore, the aforementioned second shell 200 can be fitted onto the outer surface of the first shell 100, where the outer surface of the first shell 100 refers to the wall surface opposite to the cavity wall of the first cavity 110. When the second shell 200 is fitted onto the first shell 100, the cavity walls of the first cavity 110 and the second cavity 210 together form a groove, resulting in the cavity wall of the storage cavity 300 not being a flat surface, but rather a stepped surface. This can cause the battery cell 400, after being placed in the storage cavity 300, to impact the cavity wall and drop active material, leading to a short circuit and failure of the battery cell 400. Therefore, please refer to... Figure 1 and Figure 2 In some embodiments, the battery 10 further includes a flattening member 500. The cavity wall of the second cavity 210 includes a first wall 211 and a second wall 212, with the first wall 211 surrounding the edge connected to the second wall 212. The shape of the first wall 211 can be a hollow cube or a cuboid, and the shape of the second wall 212 can be a cube or a cuboid. The first wall 211 includes a first part 212 and a second part 213. The first part 212 is welded to the first shell 100, and the flattening member 500 is connected to the second part 213, and the flattening member 500 is flush with the cavity wall of the first cavity 110. That is, the original cavity wall of the storage cavity 300 is in a state where one side is higher than the other, while the design of the flattening member 500 can make the cavity wall of the storage cavity 300 a flat surface, thereby effectively avoiding damage to the cell 400.

[0077] Furthermore, in some embodiments, the flattening member 500 surrounds at least a portion of the battery cell 400. Specifically, the flattening member 500 may surround two sides, the bottom surface, and the top surface of the battery cell 400, or the flattening member 500 may surround one side and the bottom surface of the battery cell 400, thereby effectively protecting the battery cell 400.

[0078] Furthermore, the specific method by which the flattening element 500 is connected to the second part 213 is described below. In some embodiments, the flattening element 500 is coated on the second part 213. That is, the flattening element 500 is formed by coating on the second part 213, wherein the material of the flattening element 500 can be an insulating material.

[0079] Furthermore, the specific method by which the flattening component 500 is connected to the second part 213 is described below. In some embodiments, the flattening component 500 is bonded to the second part 213. The material of the flattening component 500 can be one of polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, etc. The flattening component 500 is resistant to electrolyte corrosion, has good physicochemical stability, and does not melt below 150°C. The flattening component 500 can be bonded to the second part 213 by adhesive bonding, which facilitates processing and improves work efficiency.

[0080] Further, please refer to Figure 1 and Figure 2 In some embodiments, along the thickness direction of the first shell 100, which can be the thickness direction of the battery 10, the dimension of the first part 212 is A, the dimension of the second cavity 210 is C, and the dimension of the flattening part 500 is D, where CA-1mm≤D≤CA. D can be 2mm or 3mm, etc. Specifically, when the dimension of D is too small, the gap between the first shell 100 and the flattening part 500 in the thickness direction of the cell 400 is too large, failing to improve reliability and prevent failure. When the dimension of D is too large, this may cause the flattening part 500 and the first shell 100 to partially overlap, resulting in interference.

[0081] Further, please refer to Figure 1 and Figure 2 In some embodiments, the cavity wall of the second cavity 210 includes a first wall 211 and a second wall 212, with the first wall 211 surrounding the edge connected to the second wall 212. The first wall 211 includes a first portion 212 and a second portion 213. The first portion 212 is welded to the first shell 100. Along the thickness direction of the first shell 100, the size of the first portion 212 is A, and the size of the storage cavity 300 is B, where 0.2mm ≤ A ≤ 0.5B. Specifically, the size of the first portion 212 is the size at which the first shell 100 and the second shell 200 are welded. When the size of A is too small, this may affect the airtightness of the weld or result in insufficient weld strength, leading to lower reliability of the battery 10. When the size of A is too large, this will result in a shallow depth of the storage cavity 300, wasting space in the battery 10 and resulting in lower energy density of the battery 10.

[0082] Further, please refer to Figure 1 and Figure 2 In some embodiments, the size of the second cavity 210 is C, where A+2mm≤C≤0.9B+A. Specifically, when the size of C is too small, the size of the second cavity 210 is too small, which may result in a lower energy density of the battery 10. Furthermore, the second cavity 210 can be insulated from the terminal post 600; if the second cavity 210 is too small, the size of the connector connected to the terminal post 600 will be too small, reducing the current carrying capacity. When the size of C is too large, the second shell 200 is easily damaged during the stamping process of forming the second cavity 210.

[0083] Further, please refer to Figure 3In some embodiments, the battery 10 further includes a terminal post 600, to which the cell 400 is electrically connected. The terminal post 600 is insulated from the second shell 200, and protrudes from the second shell 200. Specifically, the negative terminal of the cell 400 can be directly connected to either the first shell 100 or the second shell 200, thereby energizing both the first shell 100 and the second shell 200. The positive terminal of the cell 400 can be connected to the terminal post 600, after which the terminal post 600 and the second shell 200 are insulated from each other, with the terminal post 600 protruding from the second shell 200. Alternatively, the cell 400 can be connected to the terminal post 600 by connecting the positive electrode tab of the cell 400 to a connecting piece, which is electrically connected to the terminal post 600. The positive terminal of the cell 400 can also be directly electrically connected to both the first shell 100 and the second shell 200, and the negative terminal of the cell 400 can be electrically connected to the terminal post 600.

[0084] In some embodiments, the electrical device includes the battery 10 of any of the above embodiments. Specifically, the first shell 100 is disposed in the second cavity 210, and the outer peripheral surface of the first shell 100 and the cavity wall of the second cavity 210 are welded together. In the prior art, when the cover plate and the metal shell are connected, the cover plate is connected to the protrusion of the metal shell, which results in a low energy density of the battery 10. In this application, the connection between the first shell 100 and the second shell 200 is mainly achieved by disposing the first shell 100 in the second cavity 210 and welding the outer peripheral surface of the first shell 100 and the cavity wall of the second cavity 210 together. This eliminates the need for a protrusion to weld the two shells together, thus enabling the battery 10 to have a higher energy density. Furthermore, the electrical device with this battery 10 has a better battery life.

[0085] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery, characterized by, The battery comprises: a first shell having a first cavity; a second shell having a second cavity, the first shell being disposed in the second cavity, an outer peripheral surface of the first shell and a cavity wall of the second cavity being welded, the first cavity and the second cavity being communicated to form a storage cavity; an electric core disposed in the storage cavity.

2. The battery of claim 1, wherein, The battery further comprises a flattening member, the cavity wall of the second cavity comprises a first wall and a second wall, the first wall surrounds an edge connected to the second wall, the first wall comprises a first part and a second part, the first part is welded to the first shell, the flattening member is connected to the second part, and the flattening member is flush with the cavity wall of the first cavity.

3. The battery of claim 2, wherein, The flattening member surrounds at least part of the electric core.

4. The battery of claim 2, wherein, The flattening member is coated on the second part.

5. The battery of claim 2, wherein, The flattening member is bonded to the second part.

6. The battery of claim 2, wherein, In a thickness direction of the first shell, a size of the first part is A, a size of the second cavity is C, and a size of the flattening member is D, C-A-1mm≤D≤C-A.

7. The battery of claim 1, wherein, The cavity wall of the second cavity comprises a first wall and a second wall, the first wall surrounds an edge connected to the second wall, the first wall comprises a first part and a second part, the first part is welded to the first shell, in a thickness direction of the first shell, a size of the first part is A, and a size of the storage cavity is B, 0.2mm≤A≤0.5B.

8. The battery of claim 7, wherein, A size of the second cavity is C, A+2mm≤C≤0.9B+A.

9. The battery of claim 1, wherein, The battery further comprises a pole, the electric core is electrically connected to the pole, the pole is insulatively connected to the second shell, and the pole protrudes relative to the second shell.

10. An electrical device, characterized by The battery comprises the battery as claimed in any one of claims 1 to 9. The battery comprises the battery as claimed in any one of claims 1 to 9.

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