Battery cell, battery and electric equipment

Abstract

The utility model discloses a battery cell, battery and electric equipment, the battery cell includes: a pole piece including foil and two active material layers, the foil includes a first surface and a second surface opposite to each other, one active material layer covers the first surface, the other active material layer covers the second surface, and the two active material layers cover the first surface. A blank area is defined by the other active material layer and the second surface; and the tab is welded and connected to the blank area. The battery cell disclosed 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 cell, a battery and an electrical device. Background Technology

[0002] In related technologies, the tab is the part that connects the battery electrode to the external circuit. It is usually made of a metal material, such as copper or aluminum, which has good electrical conductivity. The design of the tab allows the battery to be easily connected to external devices or circuits. The tab is usually connected to the electrode by welding, that is, by laser welding or ultrasonic welding, the tab and the electrode can be electrically connected.

[0003] Furthermore, when welding the tabs and electrodes, clean blank foil needs to be removed from both sides of the electrode before welding the tabs onto the blank foil. However, this results in a lower energy density for the battery cell. Utility Model Content

[0004] 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 cell capable of having a high energy density.

[0005] This utility model also proposes a battery.

[0006] This utility model also proposes an electrical device.

[0007] The battery cell according to a first aspect embodiment of the present invention includes:

[0008] An electrode sheet includes a foil and two active material layers. The foil includes a first side and a second side opposite to each other. One active material layer covers the first side, and the other active material layer covers the second side. The other active material layer and the second side define a blank area.

[0009] The electrode tab is welded to the blank area.

[0010] The battery cell according to the embodiments of this utility model has at least the following beneficial effects: an active material layer covers a first surface, and another active material layer defines a blank area on the second surface. The blank area is welded to the electrode tab. In the prior art, after the electrode tab and foil are welded, there is no active material layer on the back side of the weld joint between the electrode tab and the foil, which leads to a lower energy density of the battery cell. However, in this application, an active material layer is present on the first surface of the first side of the second surface, thus improving the energy density of the battery cell. Specifically, the battery cell can have a higher energy density.

[0011] According to some embodiments of the present invention, the electrode includes a welding surface, which is welded to the blank area, and the roughness of the welding surface is A, 0.6um≤A≤2um.

[0012] According to some embodiments of the present invention, the welding surface of the battery cell is provided with a groove.

[0013] According to some embodiments of the present invention, the battery cell has multiple grooves, which are spaced apart along the width direction of the tab.

[0014] According to some embodiments of the present invention, the battery cell has multiple grooves, which are spaced apart along the length of the tab.

[0015] According to some embodiments of the present invention, the angle between the extension direction of the groove and the length direction of the tab is an acute angle, and multiple grooves are provided, which are spaced apart along the length direction of the tab.

[0016] According to some embodiments of the present invention, the electrode is connected to the blank area by a weld, and the angle between the extension direction of the weld pool and the thickness direction of the electrode is an acute angle.

[0017] In some embodiments of the present invention, the thickness of the tab in the battery cell is greater than the thickness of the foil.

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

[0019] The battery according to the embodiments of this utility model has at least the following beneficial effects: an active material layer covers a first surface, and another active material layer defines a blank area on the second surface. The blank area is welded to the tab. In the prior art, after the tab and foil are welded, there is no active material layer on the back side of the weld joint, which leads to a lower energy density of the cell. However, in this application, the first surface of the second surface has an active material layer, thus improving the energy density of the cell. Specifically, the cell can have a higher energy density. Furthermore, the battery's energy density is also higher.

[0020] The electrical device according to a third aspect embodiment of the present invention includes the battery described in the second aspect embodiment.

[0021] The electrical device according to the embodiments of this utility model has at least the following beneficial effects: an active material layer covers a first surface, and another active material layer defines a blank area on the second surface. The blank area is welded to the tab. In the prior art, after the tab and foil are welded, there is no active material layer on the back side of the weld joint, which leads to a lower energy density of the battery cell. However, in this application, the first surface of the second surface has an active material layer, which can improve the energy density of the battery cell. Specifically, the battery cell can have a higher energy density. Furthermore, the battery's energy density is also higher. Even further, the electrical device with this battery has a longer battery life.

[0022] 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

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0024] Figure 1 This is a schematic diagram of the battery cell according to the first embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the battery cell according to the second embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the electrode tab in the battery cell according to the first embodiment of this utility model;

[0027] Figure 4 This is a schematic diagram of the electrode tab in the battery cell according to the second embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the electrode tab in the battery cell according to the third embodiment of this utility model;

[0029] Figure 6 This is a schematic diagram of the electrode tab in the battery cell according to the fourth embodiment of this utility model;

[0030] Figure 7 This is a schematic diagram of the electrode tab in the battery cell according to the fifth embodiment of this utility model;

[0031] Figure 8 This is a schematic diagram of the battery cell according to the third embodiment of this utility model.

[0032] Figure label:

[0033] Electrode 100, foil 110, active material layer 120, blank area 130, tab 200, welding surface 210, groove 220, molten pool 300. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.).

[0044] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries 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 manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.85Co0.15Al0.05O2) and their modified compounds.

[0045] 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.

[0046] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0047] 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.).

[0048] 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.

[0049] 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.

[0050] 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.

[0051] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0052] In some implementations, the battery cell also includes an isolation element disposed between the positive and negative terminals.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

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

[0061] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0062] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

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

[0064] In some implementations, the battery cell has a wound structure. The positive and negative electrode plates are wound into a wound structure.

[0065] In some implementations, the battery cell has a laminated structure.

[0066] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0067] 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.

[0068] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0069] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0070] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0071] In some implementations, the battery cell can be cylindrical, flat, or polygonal, etc.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] In related technologies, the tab is the part that connects the battery electrode to the external circuit. It is usually made of a metal material, such as copper or aluminum, which has good electrical conductivity. The design of the tab allows the battery to be easily connected to external devices or circuits. The tab is usually connected to the electrode by welding, that is, by laser welding or ultrasonic welding, the tab and the electrode can be electrically connected.

[0081] Furthermore, when welding the tabs and electrodes, clean blank foil needs to be removed from both sides of the electrode before welding the tabs onto the blank foil. However, this results in a lower energy density for the battery cell. Therefore, this application proposes a battery cell.

[0082] Please refer to Figures 1 to 2 In some embodiments, the battery cell includes a tab 200 and an electrode 100. The electrode 100 includes a foil 110 and two active material layers 120. The electrode 100 can be a positive electrode or a negative electrode. The foil 110 includes a first side and a second side opposite to each other, and the foil 110 can be an aluminum foil or a copper foil. One active material layer 120 covers the first side, and another active material layer 120 covers the second side, and the other active material layer 120 and the second side define a blank area 130. That is, the active material layer 120 is located on the first side corresponding to the blank area 130. The tab 200 is soldered to the blank area 130. Specifically, an active material layer 120 covers the first surface, and another active material layer 120 defines a blank area 130 on the second surface. The blank area 130 is welded to the tab 200. In the prior art, after the tab 200 and the foil 110 are welded, there is no active material layer 120 on the back side of the weld joint between the tab 200 and the foil 110, which results in a lower energy density of the battery cell. However, in this application, the first surface of the second surface has an active material layer 120, which can improve the energy density of the battery cell. In particular, the battery cell can have a higher energy density.

[0083] Further, please refer to Figures 3 to 7 In some embodiments, the tab 200 includes a welding surface 210, which is welded to the blank area 130. The roughness of the welding surface 210 is A, where 0.6 μm ≤ A ≤ 2 μm. Specifically, roughness refers to the degree of unevenness of the welding surface 210. Roughening the welding surface 210 can improve the welding quality between the tab 200 and the electrode 100. The roughness of the welding surface 210 can be 0.6 μm, 0.8 μm, 1 μm, or 2 μm. When the roughness of the welding surface 210 is less than 0.6 μm, the small roughness leads to greater processing difficulty and increases the manufacturing cost of the battery cell. When the roughness of the welding surface 210 is greater than 2 μm, the large roughness leads to a decrease in the strength of the tab 200, resulting in instability at the weld between the tab 200 and the electrode 100.

[0084] Furthermore, increasing the roughness of the weld surface 210 can be achieved in various ways, such as through mechanical grinding or chemical polishing. Additionally, the roughness of the weld surface 210 can also be increased by providing grooves 220 on it. For details, please refer to... Figures 3 to 7 In some embodiments, the welding surface 210 is provided with a groove 220. The shape of the groove 220 is not specifically limited; for example, the shape of the groove 220 can be rectangular, square, circular, or triangular.

[0085] Furthermore, the following describes the arrangement of the multiple grooves 220 after the welding surface 210 is provided. For details, please refer to... Figure 4 In some embodiments, multiple grooves 220 are provided, spaced apart along the width direction of the tab 200. Specifically, there may be ten grooves 220. After the ten grooves 220 are arranged along the width direction of the tab 200, the roughness of the welding surface 210 can be increased, thereby improving the welding quality of the tab 200 and the electrode 100.

[0086] Furthermore, in addition to the arrangement described above, the multiple grooves 220 can also be arranged in other ways; for details, please refer to... Figure 3 In some embodiments, multiple grooves 220 are provided, spaced apart along the length of the tab 200. There may be ten grooves 220 arranged along the length of the tab 200, which increases the roughness of the welding surface 210, thereby improving the welding quality between the tab 200 and the electrode 100.

[0087] Furthermore, in addition to the arrangement described above, the multiple grooves 220 can also be arranged in other ways; for details, please refer to... Figure 5In some embodiments, the angle between the extending direction of the groove 220 and the length direction of the tab 200 is an acute angle. Multiple grooves 220 are provided, spaced apart along the length direction of the tab 200. That is, the grooves 220 can be obliquely disposed on the welding surface 210, which can effectively improve the welding quality between the tab 200 and the electrode 100. Furthermore, in addition to being spaced apart along the length direction of the tab 200, the multiple grooves 220 can also be spaced apart along the width direction of the tab 200. Please refer to... Figures 6 to 7 Multiple grooves 220 can also be arranged in a cross pattern or in an array, without being specifically limited here.

[0088] Further, please refer to Figure 8 In some embodiments, the tab 200 is connected to the blank area 130 by a weld, and the angle between the extension direction of the weld pool 300 and the thickness direction of the tab 200 is an acute angle. Specifically, when welding the tab 200 and the electrode 100, the laser can be applied to the welding surface at a certain tilt angle. This allows the weld pool 300 to tilt towards the welding surface 210 of the tab 200, thereby increasing the depth of the weld pool 300 and improving the welding effect. The weld penetration depth can include two parts: one part on the tab 200 and the other part on the foil 110 of the electrode 100. The tilted weld penetration depth is longer than the vertical weld penetration depth, resulting in higher welding quality.

[0089] Furthermore, the electrode 100 and the tab 200 can be welded using laser equipment. The laser power ranges from 30% to 90%, the laser frequency ranges from 20 kHz to 1720 kHz, the laser speed ranges from 200 to 18000 mm / s, and the welding angle θ is from 50° to 80°. In addition, argon, helium, or nitrogen is used as a protective gas after welding. By adjusting the flow rate and blowing direction of the protective gas, the molten pool 300 and the lens are protected to prevent oxidation and contamination. For example, a side-blowing method can be used, where the protective gas is directly injected into the welding area of ​​the deep penetration weld at a certain angle through a nozzle.

[0090] Furthermore, in some embodiments, the thickness of the tab 200 is greater than the thickness of the foil 110. Specifically, since the thickness of the tab 200 is greater than the thickness of the foil 110, when welding the tab 200 and the electrode 100, welding can be performed from the tab 200 toward the electrode 100, thereby effectively preventing the foil 110 from being welded through and reducing the welding quality.

[0091] In some embodiments, the battery includes a cell from any of the above embodiments. Specifically, an active material layer 120 covers a first surface, another active material layer 120 and a second surface define a blank area 130, the blank area 130 and the tab 200 are welded together. In the prior art, after the tab 200 and the foil 110 are welded together, there is no active material layer 120 on the back side of the weld between the tab 200 and the foil 110, which results in a lower energy density of the cell. In this application, the first surface of the second surface has an active material layer 120, which can improve the energy density of the cell. Specifically, the cell can have a higher energy density. Furthermore, the battery also has a higher energy density.

[0092] In some embodiments, the electrical device includes the battery described in the above embodiments. Specifically, an active material layer 120 covers a first surface, another active material layer 120 and a second surface define a blank area 130, the blank area 130 and the tab 200 are welded together. In the prior art, after the tab 200 and the foil 110 are welded together, there is no active material layer 120 on the back side of the weld between the tab 200 and the foil 110, which results in a lower energy density of the cell. In this application, the first surface of the second surface has an active material layer 120, which can improve the energy density of the cell. Specifically, the cell can have a higher energy density. Furthermore, the energy density of the battery is also higher. Furthermore, the electrical device with this battery has a longer battery life.

[0093] 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 cell, characterized in that, include: An electrode sheet includes a foil and two active material layers. The foil includes a first side and a second side opposite to each other. One active material layer covers the first side, and the other active material layer covers the second side. The other active material layer and the second side define a blank area. The electrode tab is welded to the blank area.

2. The battery cell according to claim 1, characterized in that, The electrode tab includes a welding surface, which is welded to the blank area. The roughness of the welding surface is A, 0.6um≤A≤2um.

3. The battery cell according to claim 2, characterized in that, The welding surface is provided with a groove.

4. The battery cell according to claim 3, characterized in that, The grooves are provided in multiple ways, and are spaced apart along the width direction of the tab.

5. The battery cell according to claim 3, characterized in that, The grooves are provided in multiple ways, and are spaced apart along the length of the tab.

6. The battery cell according to claim 3, characterized in that, The angle between the extension direction of the groove and the length direction of the electrode tab is an acute angle. Multiple grooves are provided, and the multiple grooves are spaced apart along the length direction of the electrode tab.

7. The battery cell according to claim 1, characterized in that, The electrode lug is connected to the blank area by a weld, and the angle between the extension direction of the weld pool and the thickness direction of the electrode lug is an acute angle.

8. The battery cell according to claim 1, characterized in that, The thickness of the tab is greater than the thickness of the foil.

9. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 8.

10. Electrical equipment, characterized in that, Includes the battery as described in claim 9.

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