Battery monomer, battery device and power utilization device

Abstract

The invention discloses a battery monomer, a battery device and a power utilization device, and belongs to the technical field of batteries, and the battery monomer comprises a shell, an electrode terminal and an electrode assembly. The electrode terminal is arranged on the shell. The electrode assembly is located in the shell and comprises a positive pole piece, a negative pole piece, a separator and a protective layer, the separator is arranged between the positive pole piece and the negative pole piece, the positive pole piece and the negative pole piece are sequentially stacked, the stacking direction is a preset direction, the positive pole piece is electrically connected with the corresponding electrode terminal, and the negative pole piece is electrically connected with the corresponding electrode terminal. All the positive pole pieces are located between the outermost negative pole pieces on the two sides in the preset direction, a protective layer is arranged on the outer side of the outermost negative pole piece on each side, each negative pole piece comprises a main body and a negative tab which are connected with each other, the negative tab is electrically connected with the corresponding electrode terminal, and the protective layer is arranged across the negative tab of the corresponding outermost negative pole piece and the main body. And the possibility of thermal runaway caused by cracking of the negative tab on the outermost layer is reduced through the protective layer.

Description

[0001] This application is a divisional application of Chinese patent application filed on July 29, 2025, with application number 202511046571.3 and the invention title "A battery cell, battery device and power-consuming device". Technical Field

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

[0003] Batteries are being used more and more widely in daily life and industry. For example, new energy vehicles equipped with batteries are already widely used. In addition, batteries are increasingly being used in the field of energy storage.

[0004] In related technologies, the outermost negative electrode tab of a single battery cell may crack. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure provides a battery cell, a battery device, and an electrical device to reduce the possibility of cracking of the outermost negative electrode tab of the battery cell.

[0006] This application is achieved through the following technical solution.

[0007] A first aspect of this application provides a battery cell, comprising:

[0008] shell;

[0009] Electrode terminals are disposed on the housing;

[0010] An electrode assembly is located within the housing. The electrode assembly includes a positive electrode, a negative electrode, an insulating element, and a protective layer. The insulating element is disposed between the positive electrode and the negative electrode. The positive electrode and the negative electrode are stacked sequentially in a preset direction. The positive electrode is electrically connected to the corresponding electrode terminal. All the positive electrode are located between the outermost negative electrode on both sides along the preset direction. The protective layer is disposed on the outer side of the outermost negative electrode on each side. The negative electrode includes a body and a negative electrode tab that are connected to each other. The negative electrode tab is electrically connected to the corresponding electrode terminal. The protective layer spans the negative electrode tab and the body of the corresponding outermost negative electrode.

[0011] In this embodiment of the disclosure, a protective layer is disposed across the negative electrode tab and the main body of the corresponding outermost negative electrode sheet, thereby reducing the possibility of the negative electrode tab cracking near the main body.

[0012] In some embodiments, at least one side of the protective layer includes a first sub-layer and a second sub-layer that are interconnected. The first sub-layer is electrically connected to the negative electrode tab. Along a predetermined direction, the projection area of ​​the first sub-layer at least partially overlaps with the projection area of ​​the negative electrode tab, and the projection area of ​​the second sub-layer at least partially overlaps with the projection area of ​​the main body.

[0013] In this embodiment of the present disclosure, the first sub-layer is connected to the negative electrode tab, which can constrain the position of the protective layer relative to the negative electrode tab, thereby better protecting the negative electrode tab.

[0014] In some embodiments, along a preset direction, the outer contour of the projection area of ​​the second sub-layer coincides with the outer contour of the projection area of ​​the main body.

[0015] In this embodiment, the main structural part of the negative electrode sheet is the main body. The outer contour of the projection area of ​​the second sub-layer coincides with the outer contour of the projection area of ​​the main body. Basically, the negative electrode sheet can be used as a protective layer or the protective layer can be made by the cutting mechanism for making the negative electrode sheet. This is beneficial to improve the versatility of the negative electrode sheet and the protective layer or to improve the versatility of the cutting mechanism for making the negative electrode sheet and the cutting mechanism for making the protective layer.

[0016] In some embodiments, the projection area of ​​the negative electrode tab is located within the projection area of ​​the first sub-layer along the preset direction.

[0017] In this embodiment, the first sublayer can almost completely cover the negative electrode tab, thereby providing better protection for the negative electrode tab.

[0018] In some embodiments, the second sublayer includes a current collector layer that is electrically connected to the first sublayer.

[0019] In this embodiment, the current collector and the first sublayer are electrically connected. Both the current collector and the first sublayer are conductive materials, and their material properties are similar, allowing for a strong connection. The first sublayer and the current collector bear the tension during the bending process of the preset tab cluster.

[0020] In some embodiments, the first sublayer, the current collector layer, and the negative electrode tab are all made of the same material.

[0021] In this embodiment, the versatility of the negative electrode sheet and the protective layer is improved.

[0022] In some embodiments, the second sub-layer further includes an enhancement layer, wherein the current collection layer is provided with an enhancement layer on at least one side along a preset direction, and the enhancement layer is connected to the current collection layer.

[0023] In this embodiment of the disclosure, the thickness of the current collection layer is relatively thin. The current collection layer is reinforced by a reinforcement layer connected to the current collection layer, which helps to reduce the cracking of the current collection layer.

[0024] In some embodiments, the enhancement layer is a negative electrode active material layer.

[0025] In this embodiment, the protective layer includes a first sublayer, a current collector layer, and a negative electrode active material layer. The structure of the protective layer is basically the same as that of the negative electrode sheet, which is beneficial to improving the versatility of the negative electrode sheet and the protective layer.

[0026] In some embodiments, the reinforcing layer is made of an insulating material, and the reinforcing layer is located on the side of the current collector layer that is away from the positive electrode sheet along a predetermined direction.

[0027] In this embodiment, the reinforcing layer is located on the side of the current collector layer that is away from the positive electrode sheet along a preset direction. This reduces the possibility of cracking in the current collector layer and helps to improve the insulation between the current collector layer and the outer shell.

[0028] In some embodiments, the electrode assembly further includes an adhesive layer bonded to the outside of the protective layer.

[0029] In this embodiment, the adhesive layer is bonded to the outside of the corresponding protective layer, which facilitates better insulation between the negative electrode tab and the protective layer. The arrangement of the protective layer also helps reduce the pulling force of the adhesive layer on the outermost negative electrode tab, thus lowering the possibility of cracking.

[0030] In some embodiments, the insulating element is provided between the protective layer and the negative electrode adjacent to the protective layer.

[0031] In this embodiment of the disclosure, an insulating element is used to insulate the protective layer from the negative electrode sheet.

[0032] In some embodiments, the number of protective layers on each side is at least two, and the at least two protective layers on each side are arranged in a predetermined direction.

[0033] In this embodiment of the present disclosure, at least two protective layers on each side are arranged along a preset direction, and the outermost negative electrode sheet can be well protected by multiple protective layers.

[0034] In some embodiments, the spacer is provided between two adjacent protective layers.

[0035] In this embodiment of the present disclosure, an insulating element is provided between two adjacent protective layers, which effectively insulates the two adjacent protective layers.

[0036] This disclosure provides a battery device including a battery cell from any of the above embodiments.

[0037] This disclosure provides an electrical device, including a battery cell or a battery device according to any of the above embodiments, wherein the battery cell or battery device is used to store or provide electrical energy. Attached Figure Description

[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0039] Figure 1 This is a schematic diagram of the structure of an electrical device according to an embodiment of the present disclosure;

[0040] Figure 2 This is a schematic diagram of the structure of the battery device according to an embodiment of the present disclosure;

[0041] Figure 3 This is a schematic diagram of the structure of a single battery cell according to an embodiment of this disclosure;

[0042] Figure 4 This is a schematic diagram of the structure of the negative electrode sheet according to an embodiment of the present disclosure. The figure shows a projected view along a preset direction.

[0043] Figure 5 This is a schematic diagram of the structure of the protective layer according to an embodiment of the present disclosure. The figure shows a projected view along a preset direction.

[0044] Figure 6 for Figure 5 A cross-sectional view of position AA in the middle;

[0045] Figure 7 This is a schematic diagram of the structure of the electrode assembly according to an embodiment of the present disclosure. In the figure, no separator is provided between the negative electrode sheet and the protective layer, and the negative electrode sheet and the protective layer are in direct contact. There is one protective layer on each side. The first sub-layer, positive electrode tab and negative electrode tab are not shown in the figure.

[0046] Figure 8 This is a schematic diagram of the structure of the electrode assembly according to an embodiment of the present disclosure. An isolation element is provided between the negative electrode sheet and the protective layer, and there is one protective layer on each side.

[0047] Figure 9 This is a schematic diagram of the structure of the electrode assembly according to an embodiment of the present disclosure. In the figure, there is no isolation between the negative electrode and the protective layer, and the negative electrode and the protective layer are in direct contact. There are two protective layers on each side, and there is no isolation between two adjacent protective layers. Two adjacent protective layers on each side are in direct contact. The first sub-layer, positive electrode tab and negative electrode tab are not shown in the figure.

[0048] Figure 10 This is a schematic diagram of the structure of an electrode assembly according to an embodiment of the present disclosure. In the figure, an isolation element is provided between the negative electrode sheet and the protective layer. There are two protective layers on each side, and an isolation element is provided between two adjacent protective layers on each side.

[0049] Figure 11 This is a schematic diagram of the structure of the electrode assembly according to an embodiment of the present disclosure. In the figure, there is no isolation between the negative electrode and the protective layer, and the negative electrode and the protective layer are in direct contact. There are three protective layers on each side. There is no isolation between two adjacent protective layers, and two adjacent protective layers on each side are in direct contact. The first sub-layer, positive electrode tab and negative electrode tab are not shown in the figure.

[0050] Figure 12 This is a schematic diagram of the structure of an electrode assembly according to an embodiment of the present disclosure. An isolation element is provided between the negative electrode sheet and the protective layer. There are three protective layers on each side, and an isolation element is provided between two adjacent protective layers on each side.

[0051] Explanation of reference numerals in the attached figures

[0052] 1000, Vehicle; 100, Battery Unit; 200, Controller; 300, Motor; 400, Housing; 401, First Housing; 402, Second Housing; 500, Battery Cell; 1, Outer Shell; 11, Housing; 12, End Cap; 2, Electrode Terminal; 3, Electrode Assembly; 31, Positive Electrode; 311, Body; 312, Positive Tab; 32, Negative Electrode; 321, Main Body; 322, Negative Tab; 33, Separator; 34, Protective Layer; 341, First Sublayer; 342, Second Sublayer; 3421, Current Collector Layer; 3422, Reinforcement Layer; Preset Direction R1. Detailed Implementation

[0053] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the embodiments of this disclosure are intended to cover non-exclusive inclusion.

[0055] In the description of the embodiments of this application, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0056] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0057] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0058] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0059] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0060] In related technologies, a single battery cell includes a casing, electrode terminals, and an electrode assembly, with the electrode assembly located within the casing. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive and negative electrode sheets are stacked sequentially, forming a stacked structure. The negative electrode includes an interconnected main body and a negative tab, which is electrically connected to the corresponding electrode terminal. The negative tab of the outermost negative electrode is most susceptible to tensile stress, and cracking may occur during overall bending. Cracked negative tabs may prevent ions from embedding into the corresponding negative electrode, leading to the deposition of the metal corresponding to the ions and subsequent thermal runaway.

[0061] For example, a cracked negative electrode tab may prevent lithium ions from embedding into the corresponding negative electrode sheet, causing lithium plating and thermal runaway.

[0062] In this embodiment, a protective layer is disposed across the negative electrode tab and the main body of the corresponding outermost negative electrode sheet. During the overall bending process of the negative electrode tab of each negative electrode sheet, the protective layer bends along with the negative electrode tab. The outer protective layer is more affected by the tension. Even if it cracks, it is the protective layer that cracks instead of the negative electrode tab. The negative electrode tab of the outermost negative electrode sheet is less affected by the tension during the bending process, which helps to reduce the cracking of the negative electrode tab of the outermost negative electrode sheet near the main body. Correspondingly, it reduces the possibility of thermal runaway caused by metal ion precipitation.

[0063] The protective layer scheme for the electrode assembly in this application can be used not only for individual battery cells, but also for battery devices and electrical devices.

[0064] This application provides an electrical device; please refer to [link / reference]. Figure 1 This includes individual battery cells or battery devices used to store or provide electrical energy.

[0065] In some embodiments, the power supply device also includes a device body, and a battery device is mounted on the device body to supply power to the device body.

[0066] Electrical devices are devices that use electrical energy as their energy source to perform corresponding functions by consuming electrical energy. For example, electrical devices can be, but are 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.

[0067] The main body of a device refers to the main structure that consumes electrical energy to perform its corresponding functions. For example, an electrical device can be a mobile phone, where the main body is the part that enables communication and other functions, powered by individual battery cells or battery packs. Similarly, an electrical device can be a car, where the main body is the part that provides seating and allows the vehicle to move on the road, powered by individual battery cells or battery packs.

[0068] The following description will be based on an example of an electrical device, specifically a vehicle 1000, in some embodiments of this application.

[0069] Some embodiments of this application provide a vehicle 1000 that can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Please refer to... Figure 1 The vehicle 1000 has a battery device 100 installed inside, which can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, it can serve as the vehicle 1000's operating power source. The vehicle 1000 may also include a controller 200 and a motor 300, whereby the controller 200 can control the battery device 100 to supply power to the motor 300. For example, the battery device 100 can meet the power needs of the vehicle 1000 during startup, navigation, and operation.

[0070] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0071] In some embodiments, the battery device 100 may be a battery pack.

[0072] In some embodiments, the battery device 100 may be an energy storage device.

[0073] The battery device 100 of this application embodiment includes a battery cell 500. The battery cell 500 is used to store or provide electrical energy.

[0074] At least two battery cells 500 in the battery device are connected in series, parallel or mixed.

[0075] In this embodiment of the application, the battery cell 500 can be a secondary battery. A secondary battery refers to a battery cell 500 that can be used again after being discharged by recharging to activate the active materials.

[0076] The battery cell 500 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.

[0077] The battery cell 500 includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the negative and positive electrodes. During the charging and discharging process of the battery cell 500, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through. In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0078] 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.

[0079] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. 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 alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0080] 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 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 iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may 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 Mn1 / 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 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0081] In some embodiments, please refer to Figure 2 The battery device 100 also includes a housing 400, and individual battery cells 500 are installed inside the housing 400.

[0082] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0083] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, 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 sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0085] 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.

[0086] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 500. 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 battery cell 500 may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0087] In some embodiments, the negative electrode sheet can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, or foamed alloy, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0088] In some embodiments, the negative electrode sheet may be made of foamed carbon.

[0089] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0090] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0091] In some embodiments, the electrode assembly further includes a spacer disposed between the positive electrode and the negative electrode.

[0092] In some embodiments, the separator is 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] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can 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 can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0094] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0095] In some embodiments, the battery cell 500 also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0096] Liquid electrolytes include electrolyte salts and solvents.

[0097] In some embodiments, the electrolyte salt may be selected from 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.

[0098] In some embodiments, the solvent may be selected from at least one of 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 of 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.

[0099] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performance of the battery cell 500, such as additives that improve the overcharge / fast charge performance of the battery cell 500, additives that improve the high-temperature performance of the battery cell 500, additives that improve the low-temperature performance of the battery cell 500, etc.

[0100] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0101] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0102] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0103] As an example, inorganic solid electrolytes can be 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 phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0104] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0105] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0106] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0107] In some implementations, the electrode assembly is a stacked structure.

[0108] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0109] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0110] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0111] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0112] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0113] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0114] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0115] In some embodiments, please refer to Figure 2 The battery device 100 also includes a housing 400, and individual battery cells 500 are installed inside the housing 400.

[0116] As an example, the housing 400 may include a first housing 401 and a second housing 402. The first housing 401 and the second housing 402 are fastened together to form a closed space inside the housing 400 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing 401 may be a top cover or a bottom plate.

[0117] For the battery cell 500 in this embodiment, please refer to [link / reference needed]. Figure 3 and Figure 4 ,as well as Figures 7-12 The battery cell 500 includes a housing 1, electrode terminals 2, and electrode assembly 3. The electrode terminals 2 are disposed in the housing 1. The electrode assembly 3 is located inside the housing 1 and includes a positive electrode 31, a negative electrode 32, a separator 33, and a protective layer 34. A separator 33 is disposed between the positive electrode 31 and the negative electrode 32. The positive electrode 31 and the negative electrode 32 are stacked sequentially in a preset direction R1. The positive electrode 31 is electrically connected to the corresponding electrode terminal 2. All positive electrode 31 are located between the outermost negative electrode 32 on both sides along the preset direction R1. A protective layer 34 is disposed on the outer side of the outermost negative electrode 32 on each side. The negative electrode 32 includes a body 321 and a negative electrode tab 322 that are connected to each other. The negative electrode tab 322 is electrically connected to the corresponding electrode terminal 2. The protective layer 34 spans the negative electrode tab 322 and the body 321 of the corresponding outermost negative electrode 32.

[0118] Each outermost negative electrode 32 on each side is provided with a protective layer 34. All positive electrode 31 and all negative electrode 32 of the electrode assembly 3 are located between the two protective layers 34 along a preset direction R1.

[0119] All positive electrode plates 31 are located between the outermost negative electrode plates 32 on both sides along the preset direction R1. The positive electrode plates 31 are shielded as much as possible inside the negative electrode plates 32 to reduce the possibility of the positive electrode plates 31 directly contacting the electrolyte and depositing metal ions.

[0120] The outer casing 1 is the main structure that houses the electrode assembly 3, and the outer casing 1 provides good protection for the electrode assembly 3.

[0121] For example, please refer to Figures 6-12 The positive electrode 31 and the negative electrode 32 are stacked in the direction shown by arrow R1 in the figure.

[0122] For example, electrode terminal 2 can be a pole post.

[0123] For example, the separator 33 can be a separator membrane.

[0124] For example, the separator 33 may be partially located between the positive electrode 31 and the negative electrode 32, or partially located outside the positive electrode 31 and the negative electrode 32.

[0125] The positive electrode 31 and the negative electrode 32 are stacked in sequence, that is, the electrode assembly 3 is a stacked structure.

[0126] For example, electrode assembly 3 is electrically connected to electrode terminal 2.

[0127] For example, the positive electrode 31 includes a body 311 and a positive electrode tab 312 that are connected to each other, and the positive electrode tab 312 is electrically connected to the corresponding electrode terminal 2.

[0128] For example, at least two positive tabs 312 are welded.

[0129] For example, the electrode terminal 2 electrically connected to the positive electrode tab 312 is a positive polarity electrode terminal 2.

[0130] For example, the body 311 of the positive electrode 31 is generally in the shape of a sheet structure.

[0131] For example, the body 311 includes a positive current collector and a positive active material layer disposed on the positive current collector, the material of the positive active material layer being a positive active material. The positive current collector is connected to the positive tab 312.

[0132] For example, the positive current collector and the corresponding positive tab 312 are integrally formed.

[0133] For example, the main body 321 includes a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, the material of the negative electrode active material layer being a negative electrode active material. The negative electrode current collector is connected to the negative electrode tab 322.

[0134] For example, the negative current collector and the negative electrode tab 322 are integrally formed.

[0135] For example, the electrode terminal 2 electrically connected to the negative electrode tab 322 is a negative polarity electrode terminal 2.

[0136] For example, the negative electrode tab 322 is welded to the corresponding electrode terminal 2.

[0137] For example, the protective layer 34 is connected to the negative electrode tab 322 of the corresponding outermost negative electrode sheet 32.

[0138] For example, the protective layer 34 is welded to the negative electrode tab 322 of the corresponding outermost negative electrode sheet 32.

[0139] For example, the housing 1 includes a housing 11 and an end cap 12 that are connected to each other, the electrode assembly 3 is located in the space enclosed by the housing 11 and the end cap 12, and the electrode terminal 2 is mounted on the end cap 12.

[0140] For example, before the electrode assembly 3 is inserted into the housing, the negative electrode tab 322 of the electrode assembly 3 can be connected to the electrode terminal 2 installed on the end cover 12 in an unbent state. Then, the electrode assembly 3 is placed into the housing 11 and the end cover 12 is flipped so that the end cover 12 covers the opening of the housing 11 for welding. During the flipping of the end cover 12, the negative electrode tab 322 of the outermost negative electrode sheet 32 ​​may be bent.

[0141] For example, the housing 11 and the end cap 12 are welded together.

[0142] For example, before the negative tab 322 is connected to the electrode terminal 2, the negative tab 322 of the electrode assembly 3 may be bent due to touch or other needs.

[0143] The outermost negative electrode 32 of the stacked structure refers to the fact that, along the preset direction R1, all other negative electrode 32s are located between the outermost negative electrode 32s on both sides, and the outermost negative electrode 32 is adjacent to one of the positive electrode layers 31. There are no other negative electrode 32s between the outermost negative electrode 32 and the adjacent positive electrode layer 31.

[0144] For example, the battery cell 500 is a lithium-ion battery.

[0145] For example, along a preset direction R1, a separator 33 is provided on the side of the protective layer 34 facing away from the positive electrode 31, and a portion of the separator 33 covers the side of the protective layer 34 facing away from the positive electrode 31. The side of the protective layer 34 facing away from the positive electrode 31 is the outer side of the protective layer 34.

[0146] In this embodiment, all positive electrode plates 31 are located between the outermost negative electrode plates 32 on both sides along a predetermined direction R1. A protective layer 34 is provided on the outer side of each outermost negative electrode plate 32. The outermost layer is the protective layer 34, which, during the bending process of the negative electrode tab 322 and the protective layer 34 together, primarily bears the tension during bending. The protective layer 34 spans between the negative electrode tab 322 and the main body 321 of the corresponding outermost negative electrode plate 32, reducing the tension on the negative electrode tab 322 near the main body 321. This lowers the possibility of cracking of the negative electrode tab 322 near the main body 321, and correspondingly reduces the possibility of thermal runaway caused by metal ion deposition. Since the protective layer 34 primarily bears the tension during bending, even if the protective layer 34 cracks, it will not significantly affect the normal charging and discharging between the negative electrode plate 32 and the positive electrode plate 31 corresponding to the negative electrode tab 322.

[0147] In some embodiments, please refer to Figure 5 and Figure 6At least one protective layer 34 includes a first sub-layer 341 and a second sub-layer 342 that are connected to each other. The first sub-layer 341 is electrically connected to the negative electrode tab 322. Along a preset direction R1, the projection area of ​​the first sub-layer 341 at least partially overlaps with the projection area of ​​the negative electrode tab 322, and the projection area of ​​the second sub-layer 342 at least partially overlaps with the projection area of ​​the main body 321.

[0148] For example, the first sublayer 341 is welded to the negative electrode tab 322.

[0149] For example, the first sublayer 341 may be copper foil.

[0150] In this embodiment, the first sub-layer 341 is electrically connected to the negative electrode tab 322, and the projection area of ​​the first sub-layer 341 and the projection area of ​​the negative electrode tab 322 at least partially overlap, which facilitates the electrical connection between the interconnected protective layer 34 and the negative electrode tab 322 as a whole and the electrode terminal 2. The connection between the protective layer 34 and the negative electrode tab 322 can better constrain the position of the protective layer 34 relative to the negative electrode tab 322, which is beneficial for the protective layer 34 to better protect the negative electrode tab 322.

[0151] It is understood that the specific structure of the protective layer 34 is not limited. For example, along the preset direction R1, the projection area of ​​the first sub-layer 341 at least partially overlaps with the projection area of ​​the negative electrode tab 322. The first sub-layer 341 may block the negative electrode tab 322 or contact the negative electrode tab 322 but not connect to it.

[0152] In some embodiments, please refer to Figures 5-12 Both protective layers 34 include a first sublayer 341 and a second sublayer 342 that are interconnected. Both first sublayers 341 are connected to the corresponding negative electrode tabs 322.

[0153] In some embodiments, please refer to Figures 4 to 12 Along the preset direction R1, the outer contour of the projection area of ​​the second sub-layer 342 coincides with the outer contour of the projection area of ​​the main body 321.

[0154] The outer contour of the projection area of ​​the second sub-layer 342 coincides with the outer contour of the projection area of ​​the main body 321, and the shape of the second sub-layer 342 is roughly the same as the shape of the main body 321.

[0155] For example, when projecting along the direction in which the positive electrode 31 and the negative electrode 32 are stacked sequentially, the outer contour of the projection area of ​​the first sub-layer 341 coincides with the outer contour of the projection area of ​​the negative electrode tab 322. The shape of the first sub-layer 341 is approximately the same as the shape of the negative electrode tab 322.

[0156] In this embodiment, the main structural part of the negative electrode sheet 32 ​​is the main body 321. The outer contour of the projection area of ​​the second sub-layer 342 coincides with the outer contour of the projection area of ​​the main body 321. Basically, the negative electrode sheet 32 ​​can be used as the protective layer 34 or the protective layer 34 can be made by the cutting mechanism for making the negative electrode sheet 32. This is beneficial to improve the versatility of the negative electrode sheet 32 ​​and the protective layer 34 or improve the versatility of the cutting mechanism for making the negative electrode sheet 32 ​​and the cutting mechanism for making the protective layer 34.

[0157] It is understood that the structure of the second sub-layer 342 is not limited. For example, along the preset direction R1, the projection area of ​​the second sub-layer 342 is located within the projection area of ​​the main body 321, or the projection area of ​​the main body 321 is located within the projection area of ​​the second sub-layer 342, or the outer contour of the projection area of ​​the second sub-layer 342 intersects with the outer contour of the projection area of ​​the main body 321 to form a finite number of intersection points.

[0158] In some embodiments, along a preset direction R1, the projection area of ​​the negative electrode tab 322 is located within the projection area of ​​the first sub-layer 341.

[0159] The projection area of ​​the negative electrode tab 322 is located within the projection area of ​​the first sub-layer 341, and the negative electrode tab 322 can be almost completely blocked by the first sub-layer 341 of the protective layer 34.

[0160] In this embodiment, the projection area of ​​the negative electrode tab 322 is located within the projection area of ​​the first sub-layer 341, so that the first sub-layer 341 of the protective layer 34 can almost completely block the negative electrode tab 322, thereby providing better protection for the negative electrode tab 322 of the outermost negative electrode sheet 32.

[0161] In some embodiments, please refer to Figure 5 and Figure 6 The second sublayer 342 includes a current collector layer 3421, which is electrically connected to the first sublayer 341.

[0162] For example, the current collector layer 3421 is integrally formed with the first sublayer 341. This facilitates the fabrication of the protective layer 34 and improves the tensile strength of the protective layer 34.

[0163] For example, the current collector layer 3421 is welded to the first sublayer 341.

[0164] For example, the current collector layer 3421 is made of the same material as the negative electrode current collector.

[0165] In this embodiment, the current collector 3421 is electrically connected to the first sub-layer 341. Both the current collector 3421 and the first sub-layer 341 are conductive materials, and their material properties are similar, allowing for a strong connection. The first sub-layer 3421 and the current collector 3421 support the tension of the negative electrode tab 322 of the outermost negative electrode sheet 32 ​​during bending.

[0166] It is understood that the structure of the second sublayer 342 is not limited. For example, the material of the second sublayer 342 can be an insulating material.

[0167] In some embodiments, the first sublayer 341, the current collector layer 3421, and the negative electrode tab 322 are all made of the same material.

[0168] For example, the current collector 342 1 is a copper foil.

[0169] For example, the thickness of the copper foil can be 4.5um to 7um.

[0170] For example, the thickness of the copper foil can be 4.5um, 5um, 5.2um, 5.5um, 5.8um, 6um, 6.5um or 7um.

[0171] In this embodiment, the first sub-layer 341, the current collector layer 3421, and the negative electrode tab 322 are all made of the same material, which is beneficial to improving the versatility between the negative electrode sheet 32 ​​and the protective layer 34.

[0172] In some embodiments, please refer to Figure 5 and Figure 6 The second sub-layer 342 also includes an enhancement layer 3422. The current collection layer 3421 is provided with an enhancement layer 3422 on at least one side along the preset direction R1, and the enhancement layer 3422 is connected to the current collection layer 3421.

[0173] For example, the enhancement layer 3422 covers the flow collection layer 3421.

[0174] For example, the current collection layer 3421 is provided with reinforcement layers 3422 on both sides along the preset direction R1.

[0175] In this embodiment of the present disclosure, the current collection layer 3421 is relatively thin. The current collection layer 3421 is reinforced by the reinforcement layer 3422 connected to the current collection layer 3421, which helps to reduce the cracking of the current collection layer 3421.

[0176] It is understood that the specific structure of the protective layer 34 is not limited. For example, the second sub-layer 342 may include a current collection layer 3421 but without an enhancement layer 3422.

[0177] In some embodiments, please refer to Figure 5 and Figure 6 The reinforcement layer 3422 is the negative electrode active material layer.

[0178] For example, the negative electrode active material layer can be bonded to the current collector layer 3421.

[0179] For example, the material of the negative electrode active material layer can be graphite.

[0180] In this embodiment, the protective layer 34 includes a first sub-layer 341, a current collector layer 3421, and a negative electrode active material layer. The structure of the protective layer 34 is basically the same as that of the negative electrode sheet 32, which is beneficial to improving the versatility of the negative electrode sheet 32 ​​and the protective layer 34.

[0181] In some embodiments, please refer to Figure 5 and Figure 6 The reinforcing layer 3422 is made of insulating material and is located on the side of the current collector layer 3421 away from the positive electrode plate 31 along the preset direction R1.

[0182] The reinforcement layer 3422 is located on the side of the current collector layer 3421 that is away from the positive electrode plate 31 along the preset direction R1, that is, the reinforcement layer 3422 is located on the outside of the corresponding current collector layer 3421.

[0183] For example, along the preset direction R1, the projection area of ​​the enhancement layer 3422 is located within the projection area of ​​the current collection layer 3421.

[0184] For example, along the preset direction R1, the outer contour of the projection area of ​​the reinforcement layer 3422 coincides with the outer contour of the projection area of ​​the current collection layer 3421.

[0185] In this embodiment, the reinforcing layer 3422 is located on the side of the current collector layer 3421 that is away from the positive electrode plate 31 along a preset direction R1. This reduces the possibility of cracking of the current collector layer 3421 and improves the insulation between the current collector layer 3421 and the outer shell 1.

[0186] In some embodiments, the electrode assembly 3 further includes an adhesive layer bonded to the outside of the corresponding protective layer 34.

[0187] For example, the adhesive layer can be double-sided tape. In this embodiment of the disclosure, by bonding the adhesive layer to the outside of the corresponding protective layer 34, it is beneficial to provide better insulation between the negative electrode tab 322 and the protective layer 34. The arrangement of the protective layer 34 helps to reduce the pulling force of the adhesive layer on the negative electrode tab 322 of the outermost negative electrode sheet 32 ​​during bending, thereby reducing the possibility of cracking of the outermost negative electrode tab 322.

[0188] It is understood that the structure of electrode assembly 3 is not limited. For example, an adhesive layer may not be provided.

[0189] In some embodiments, please refer to Figures 7-12 An isolation element 33 is provided between the protective layer 34 and the negative electrode 32 adjacent to the protective layer 34.

[0190] For example, along the preset direction R1, among all the positive electrode plates 31 and negative electrode plates 32 of the electrode assembly 3, the outermost layer is the negative electrode plate 32, all the positive electrode plates 31 are located between the negative electrode plates 32 on both sides, and an isolation member 33 is provided between the outermost negative electrode plate 32 and the protective layer 34.

[0191] In this embodiment of the disclosure, the protective layer 34 and the negative electrode plate 32 are insulated by the insulating member 33.

[0192] It is understood that the specific arrangement of the protective layer 34 is not limited. For example, the protective layer 34 is in direct contact with the outermost negative electrode 32, and no insulating member 33 is provided between the protective layer 34 and the negative electrode 32.

[0193] In some embodiments, please refer to Figures 9-12 The number of protective layers 34 on each side is at least two, and at least two protective layers 34 on each side are arranged along a preset direction R1.

[0194] For example, the number of each protective layer 34 can be two, three, or five.

[0195] For example, two protective layers 34 on each side are stacked sequentially.

[0196] For example, three protective layers 34 on each side are stacked sequentially.

[0197] In this embodiment of the present disclosure, at least two protective layers 34 are arranged along a preset direction R1 on each side, and the outermost negative electrode sheet 32 ​​can be well protected by the multiple protective layers 34.

[0198] It is understood that the specific number of protective layers 34 on each side is not limited. For example, the number of protective layers 34 on each side can be one layer.

[0199] In some embodiments, please refer to Figures 9-12 An isolation element 33 is provided between two adjacent protective layers 34.

[0200] For example, an isolation membrane is provided between two adjacent protective layers 34.

[0201] In this embodiment of the present disclosure, an isolation member 33 is provided between two adjacent protective layers 34, and the isolation member 33 provides good insulation between the two adjacent protective layers 34.

[0202] It is understood that the specific arrangement of the protective layer 34 is not limited. For example, there may be no spacer 33 between two adjacent protective layers 34, and the two adjacent protective layers 34 on each side may be in direct contact.

[0203] For the battery cell 500 of this embodiment, please refer to [link / reference]. Figures 3 to 12 The battery cell 500 includes a housing 1, electrode terminals 2, and electrode assembly 3. The electrode terminals 2 are disposed in the housing 1. The electrode assembly 3 is located inside the housing 1 and includes a positive electrode 31, a negative electrode 32, a separator 33, and a protective layer 34. A separator 33 is disposed between the positive electrode 31 and the negative electrode 32. The positive electrode 31 and the negative electrode 32 are stacked sequentially in a preset direction R1. The positive electrode 31 is electrically connected to the corresponding electrode terminal 2. All positive electrode 31 are located between the outermost negative electrode 32 on both sides along the preset direction R1. A protective layer 34 is disposed on the outer side of the outermost negative electrode 32 on each side. The negative electrode 32 includes a body 321 and a negative electrode tab 322 that are connected to each other. The negative electrode tab 322 is electrically connected to the corresponding electrode terminal 2. The protective layer 34 spans the negative electrode tab 322 and the body 321 of the corresponding outermost negative electrode 32. Along a preset direction R1, all positive electrode plates 31 are located between the outermost negative electrode plates 32 on both sides. At least one protective layer 34 includes a first sub-layer 341 and a second sub-layer 342 that are interconnected. The first sub-layer 341 is electrically connected to the negative electrode tab 322. Along the preset direction R1, the projection area of ​​the second sub-layer 342 at least partially overlaps with the projection area of ​​the main body 321. The second sub-layer 342 includes a current collector layer 3421, which is electrically connected to the first sub-layer 341. The current collector layer 3421 is a copper foil. The second sub-layer 342 also includes a reinforcement layer 3422. The reinforcement layer 3422 is provided on at least one side of the current collector layer 3421 along the preset direction R1, and the reinforcement layer 3422 is connected to the current collector layer 3421. The number of protective layers 34 in the battery cell 500 is 2 to 10. The sum of the number of layers in the protective layer 34 and the negative electrode 32 is the sum of the number of layers in the positive electrode 31 and the protective layer 34 plus 1, that is, the number of layers in the negative electrode 32 is the number of layers in the positive electrode 31 plus 1.

[0204] For example, the reinforcing layer 3422 is a negative electrode active material layer. The structure of the protective layer 34 is basically the same as that of the negative electrode sheet 32, and the protective layer 34 and the negative electrode sheet 32 ​​can be interchanged.

[0205] For example, the reinforcing layer 3422 is made of an insulating material and is located on the side of the current collector 3421 away from the positive electrode 31 along the direction in which the positive electrode 31 and the negative electrode 32 are stacked sequentially.

[0206] For example, the insulating material may be fluororubber, silicone rubber, acrylate rubber, polyimide, ceramic coating, or silica aerogel.

[0207] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way.

Claims

1. A battery cell, characterized in that, include: shell; Electrode terminals are disposed on the housing; An electrode assembly is located within the housing. The electrode assembly includes a positive electrode, a negative electrode, an insulating element, and a protective layer. The insulating element is disposed between the positive electrode and the negative electrode. The positive electrode and the negative electrode are stacked sequentially in a preset direction. The positive electrode is electrically connected to the corresponding electrode terminal. All the positive electrode are located between the outermost negative electrode on both sides along the preset direction. The protective layer is disposed on the outer side of the outermost negative electrode on each side. The negative electrode includes a body and a negative electrode tab that are connected to each other. The negative electrode tab is electrically connected to the corresponding electrode terminal. The protective layer spans the negative electrode tab and the body of the corresponding outermost negative electrode.

2. The battery cell according to claim 1, characterized in that, The protective layer on at least one side includes a first sub-layer and a second sub-layer that are interconnected. The first sub-layer is electrically connected to the negative electrode tab. Along the preset direction, the projection area of ​​the first sub-layer at least partially overlaps with the projection area of ​​the negative electrode tab, and the projection area of ​​the second sub-layer at least partially overlaps with the projection area of ​​the main body.

3. The battery cell according to claim 2, characterized in that, Along the preset direction, the outer contour of the projection area of ​​the second sub-layer coincides with the outer contour of the projection area of ​​the main body.

4. The battery cell according to claim 2, characterized in that, Along the preset direction, the projection area of ​​the negative electrode tab is located within the projection area of ​​the first sub-layer.

5. The battery cell according to claim 2, characterized in that, The second sublayer includes a current collector layer, which is electrically connected to the first sublayer.

6. The battery cell according to claim 5, characterized in that, The first sub-layer, the current collector layer, and the negative electrode tab are all made of the same material.

7. The battery cell according to claim 5, characterized in that, The second sub-layer further includes an enhancement layer, and the current collection layer is provided with an enhancement layer on at least one side along the preset direction, and the enhancement layer is connected to the current collection layer.

8. The battery cell according to claim 7, characterized in that, The enhancement layer is a negative electrode active material layer.

9. The battery cell according to claim 7, characterized in that, The reinforcing layer is made of an insulating material and is located on the side of the current collector layer opposite to the positive electrode sheet along the preset direction.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The electrode assembly also includes an adhesive layer, which is bonded to the outside of the corresponding protective layer.

11. The battery cell according to any one of claims 1 to 9, characterized in that, The insulating element is provided between the protective layer and the negative electrode adjacent to the protective layer.

12. The battery cell according to any one of claims 1 to 9, characterized in that, The number of protective layers on each side is at least two, and the at least two protective layers on each side are arranged along the preset direction.

13. The battery cell according to claim 12, characterized in that, The isolation element is provided between two adjacent protective layers.

14. A battery device, characterized in that, Includes the battery cell according to any one of claims 1 to 13.

15. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1 to 13 or a battery device according to claim 14, wherein the battery cell or battery device is used to store or provide electrical energy.

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