Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, a pressure relief piece in the battery monomer is provided with a cracking structure, a protection piece covers a through hole and is located on one side, deviating from an electrode assembly, of a shell, a second part in the protection piece is arranged along the periphery of a first part and is connected to the shell, the first part is of a transparent structure, the second part comprises a color developing area, and the color developing area is provided with a color developing area. The projection of the color developing area is located on the outer side of the projection of the cracking structure in the axial direction of the through hole. The projection of the color developing area in the axial direction of the through hole is located on the outer side of the projection of the cracking structure in the axial direction of the through hole, so that the arranged color developing area can conveniently distinguish whether the through hole is connected with the protection piece or not, the omission of the protection piece is reduced, the cracking structure is not prone to being shielded, and whether the cracking structure has defects or not can be conveniently detected; therefore, the possibility that dirt enters the through hole is reduced, and the possibility that a defective pressure relief piece is arranged in the battery monomer is reduced, so that the battery monomer has relatively high reliability.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] Batteries have the advantages of high specific energy and high power density. They are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric tools, etc.

[0003] As the application fields of batteries continue to expand, the reliability of batteries has attracted more and more attention from technicians in this field. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, wherein the battery cell has high reliability.

[0005] In a first aspect, some embodiments of the present application provide a battery cell, which includes a shell, an electrode assembly, a pressure relief piece and a protective piece. The shell forms a accommodating space, the shell is provided with a through hole, and the through hole can connect the accommodating space with the outside world. The electrode assembly is arranged in the accommodating space, the pressure relief piece blocks the through hole and is connected to the shell, the pressure relief piece is provided with a cracking structure, the protective piece covers the through hole and is located on the side of the shell away from the electrode assembly, the second part of the protective piece is arranged along the periphery of the first part and is connected to the shell, the first part is a transparent structure, and the second part includes a color display area, and along the axial direction of the through hole, the projection of the color display area is located outside the projection of the cracking structure.

[0006] Since the first part of the protective member is a transparent structure, the second part including the color display area is arranged along the outer periphery of the first part, and the projection of the color display area in the axial direction of the through hole is located outside the projection of the cracking structure in the axial direction of the through hole, the set color display area is convenient for distinguishing whether the protective member is connected to the through hole, reducing the omission of the protective member, and is not easy to block the cracking structure, which facilitates the detection of whether the cracking structure has defects. This not only reduces the possibility of dirt entering the through hole, but also helps to reduce the possibility of a defective pressure relief member being provided in the battery cell, so that the battery cell has higher reliability.

[0007] According to the battery cell provided in some embodiments of the present application, the second portion further includes a transparent region arranged along the inner periphery of the color development region, and the transparent region is connected to the outer periphery of the first portion.

[0008] According to the battery cell provided in some embodiments of the present application, a first adhesive layer is provided on the side of the second portion facing the outer shell, and the second portion is bonded to the outer shell through the first adhesive layer.

[0009] According to the battery cell provided in some embodiments of the present application, the second part includes a bonding area and a detachment area arranged along the circumference of the first part, the bonding area is provided with a first bonding layer, and the detachment area is not provided with the first bonding layer, and along the radial direction of the through hole, the detachment area is connected between the edge of the first part and the edge of the protective member.

[0010] According to the battery cell provided in some embodiments of the present application, a second adhesive layer is provided on the side of the first portion facing the outer shell, and the second adhesive layer is connected to the first adhesive layer.

[0011] According to the battery cells provided in some embodiments of the present application, the color development area is connected to the edge of the protective member, and in the axial direction of the through hole, the shortest distance between the projection of the crack structure and the projection of the outer edge of the color development area is A, and the width of the color development area projection is B, B<A.

[0012] According to the battery cells provided in some embodiments of the present application, B≥0.4 mm.

[0013] According to the battery cell provided in some embodiments of the present application, a boss is protruding from a side of the shell facing away from the electrode assembly, the boss is arranged around the periphery of the through hole, and the second part is connected to the boss.

[0014] According to the battery cell provided in some embodiments of the present application, in the radial direction of the through hole, the width of the boss is C, the width of the second portion is D, and 1.5C≤D≤4C.

[0015] According to the battery cell provided in some embodiments of the present application, the protective component is an integrally formed structure.

[0016] In a second aspect, some embodiments of the present application provide a battery, which includes a battery cell provided by any of the above technical solutions.

[0017] In a third aspect, some embodiments of the present application provide an electrical device, which includes a battery provided by the above technical solution, and the battery is used to provide electrical energy.

[0018] The technical solution provided by the embodiments of the present disclosure brings at least the following beneficial effects:

[0019] Some embodiments of the present application provide a battery cell, which includes a shell, an electrode assembly, a pressure relief piece and a protective piece. The shell forms a accommodating space, the shell is provided with a through hole, and the through hole can connect the accommodating space with the outside world. The electrode assembly is arranged in the accommodating space, the pressure relief piece blocks the through hole and is connected to the shell, the pressure relief piece is provided with a cracking structure, the protective piece covers the through hole and is located on the side of the shell away from the electrode assembly, the second part of the protective piece is arranged along the periphery of the first part and is connected to the shell, the first part is a transparent structure, and the second part includes a color display area. Along the axial direction of the through hole, the projection of the color display area is located outside the projection of the cracking structure. Since the first part of the protective member is a transparent structure, the second part including the color display area is arranged along the outer periphery of the first part, and the projection of the color display area in the axial direction of the through hole is located outside the projection of the cracking structure in the axial direction of the through hole, the set color display area is convenient for distinguishing whether the protective member is connected to the through hole, reducing the omission of the protective member, and is not easy to block the cracking structure, which facilitates the detection of whether the cracking structure has defects. This not only reduces the possibility of dirt entering the through hole, but also helps to reduce the possibility of a defective pressure relief member being provided in the battery cell, so that the battery cell has higher reliability.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present application. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0022] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0023] Figure 2 A schematic diagram of the disassembled structure of a battery provided in some embodiments of the present application;

[0024] Figure 3 A schematic diagram of the disassembled structure of a battery cell provided in some embodiments of the present application;

[0025] Figure 4 A schematic diagram of the disassembled structure of a battery cell provided in some other embodiments of the present application;

[0026] Figure 5 A schematic diagram of the structure of a battery cell in a disassembled protective member provided in some embodiments of the present application;

[0027] Figure 6 for Figure 5 Enlarged view of K in the middle;

[0028] Figure 7 A top view of a through hole in a battery cell provided in some other embodiments of the present application;

[0029] Figure 8 for Figure 7 The enlarged view of the H in the middle;

[0030] Fig. 9 A bottom view of a protective member in a battery cell provided in some embodiments of the present application;

[0031] Fig.10 A top view of a through hole in a battery cell provided in some embodiments of the present application;

[0032] Fig.11 for Fig. 9 Sectional view at II in the middle;

[0033] Fig.12 for Fig. 9 Cross-sectional view at JJ in the middle.

[0034] In the attached picture:

[0035] 1. End cover; 11. Through hole; 12. Boss; 2. Pressure relief part; 21. Cracking structure; 3. Protective part;

[0036] 31, first part; 311, second adhesive layer; 32, second part; 321, adhesive area; 3211, color development area; 3212, transparent area;

[0037] 322. Disengagement Zone;

[0038] 323, first adhesive layer; 4, housing;

[0039] 10. Box body; 101. First box body; 102. Second box body; 20. Battery cell; 201. Electrode assembly; 202. Casing; 203. Accommodation space; 1000. Vehicle; 100. Battery; 200. Controller; 300. Motor. DETAILED DESCRIPTION

[0040] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0041] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should have the common meanings understood by technicians in the field to which the embodiments of the present application belong.

[0042] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0043] In addition, the technical terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0044] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0045] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0046] At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields.

[0047] In the embodiment of the present application, the battery cell may be a secondary battery cell, which refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0048] The battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc., which are not limited in the embodiments of the present application.

[0049] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are inserted and removed back and forth between the positive electrode and the negative electrode.

[0050] In some embodiments, the electrode assembly further includes a separator, which is disposed between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting while allowing active ions to pass through.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0052] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.

[0053] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, silver-surface-treated aluminum, silver-surface-treated stainless steel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may 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 polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0054] As an example, the positive electrode active material layer includes a positive electrode active material. The positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as Li FePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and at least one of a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides 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, Li Mn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、L iNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、Li Ni 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Ni 0.80 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0055] In some embodiments, the positive electrode may be carbon foam or metal foam. The metal foam may be nickel foam, copper foam, aluminum foam or alloy foam. When the metal foam is used as the positive electrode, the positive electrode active material may not be provided on the surface of the metal foam, but the positive electrode active material may also be provided. As an example, lithium source material, potassium metal or sodium metal may be filled or / and deposited in the metal foam, and the lithium source material is lithium metal and / or lithium-rich material.

[0056] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0057] As an example, the negative electrode current collector may be a metal foil, a foamed metal, a foamed carbon or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, silver-surface-treated aluminum, silver-surface-treated stainless steel, a carbon electrode, carbon, nickel or titanium, etc. may be used. The foamed metal may be a foamed nickel, a foamed copper, a foamed aluminum or a foamed alloy, etc. The composite current collector may include a polymer material base and a metal layer. The composite current collector may 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 polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0058] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional 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.

[0059] In some embodiments, the negative electrode may be foamed carbon or foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum or foamed alloy, etc. When the foamed metal is used as the negative electrode sheet, the surface of the foamed metal may not be provided with a negative electrode active material, but of course, a negative electrode active material may also be provided.

[0060] As an example, a lithium source material, potassium metal or sodium metal may be filled or / and deposited in the negative electrode current collector, and the lithium source material is lithium metal and / or lithium-rich material.

[0061] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0062] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode sheet and the negative electrode sheet.

[0063] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0064] 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 special restrictions. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without special restrictions. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes.

[0065] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode sheet and the negative electrode sheet and plays the role of transmitting ions and isolating the positive and negative electrodes.

[0066] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

[0067] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0068] In some embodiments, the electrolyte salt can 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0069] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be selected from ether solvents. Ether solvents can 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, methyltetrahydrofuran, diphenyl ether and crown ether.

[0070] The gel electrolyte includes a polymer-based electrolyte skeleton network combined with an ionic liquid-lithium salt.

[0071] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0072] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0073] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous Li PON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0074] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0075] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0076] In some embodiments, the electrode assembly is a laminate structure.

[0077] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0078] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0079] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0080] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0081] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0082] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0083] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0084] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0085] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery.

[0086] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0087] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0088] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0089] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0090] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0091] As the battery is in use, the internal pressure of the battery cell will change. A pressure relief piece is usually provided on the outer shell of the battery cell to reduce the pressure fluctuation inside the battery cell, to improve the reliability of the battery cell, and to extend the service life of the battery cell. In the related art, the pressure relief piece is usually sealed in a through-hole provided on the outer shell. However, during the use of the battery cell, dust and other dirt from the outside can easily fall into the through-hole, blocking the through-hole, affecting the pressure relief of the battery cell, or entering the battery cell when the pressure relief piece is opened. Therefore, a protective piece is usually provided on the outside of the outer shell away from the electrode assembly to protect the through-hole and the pressure relief piece in the through-hole, but the protective piece can easily block the pressure relief piece, affecting the detection of defects in the pressure relief piece, which is not conducive to improving the reliability of the battery cell.

[0092] In order to improve the reliability of a battery cell, some embodiments of the present application provide a battery cell, which includes a shell, an electrode assembly, a pressure relief piece and a protective piece. The shell forms a accommodating space, the shell is provided with a through hole, and the through hole can connect the accommodating space with the outside world. The electrode assembly is arranged in the accommodating space, the pressure relief piece blocks the through hole and is connected to the shell, the pressure relief piece is provided with a cracking structure, the protective piece covers the through hole and is located on the side of the shell away from the electrode assembly, the second part of the protective piece is arranged along the periphery of the first part and is connected to the shell, the first part is a transparent structure, and the second part includes a color display area. Along the axial direction of the through hole, the projection of the color display area is located outside the projection of the cracking structure. Since the first part of the protective member is a transparent structure, the second part including the color display area is arranged along the outer periphery of the first part, and the projection of the color display area in the axial direction of the through hole is located outside the projection of the cracking structure in the axial direction of the through hole, the set color display area is convenient for distinguishing whether the protective member is connected to the through hole, reducing the omission of the protective member, and is not easy to block the cracking structure, which facilitates the detection of whether the cracking structure has defects. This not only reduces the possibility of dirt entering the through hole, but also helps to reduce the possibility of a defective pressure relief member being provided in the battery cell, so that the battery cell has higher reliability.

[0093] The battery cell described in the embodiments of the present application is suitable for use in batteries and electrical devices using batteries. The battery cell can be used for, but is not limited to, batteries, and can also be used for vehicles, aircraft, ships, electronic equipment, power tools and other products, and can improve the reliability of these products.

[0094] Electrical devices may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, etc. Vehicles may be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc. Spacecraft include aircraft, rockets, space shuttles and spacecrafts, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc.

[0095] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0096] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0097] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0098] Please refer to Figure 2 , Figure 2 An exploded diagram of a battery 100 provided for some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, and the battery cell 20 is accommodated in the housing 10. Among them, the housing 10 is used to provide a storage space for the battery cell 20. There may be multiple battery cells 20 in the battery 100, and the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells 20 are both connected in series and in parallel. Multiple battery cells 20 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the housing 10; of course, the battery 100 can also be a battery module formed by first connecting multiple battery cells 20 in series, in parallel, or in mixed connection, and then the multiple battery modules are connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the housing 10.

[0099] The box 10 may include a first box 101 and a second box 102, and the first box 101 and the second box 102 cover each other to define a placement space for accommodating the battery cells 20. The first box 101 and the second box 102 may be in various shapes, such as a cuboid, a cylinder, etc. The first box 101 may be a hollow structure with one side open, and the second box 102 may also be a hollow structure with one side open, and the open side of the second box 102 covers the open side of the first box 101, thereby forming a box 10 with a placement space.

[0100] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component for achieving electrical connection between the plurality of battery cells 20 .

[0101] Each battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0102] In some embodiments of the present application, Figure 3 As shown, the battery cell 20 includes a housing 202 and an electrode assembly 201, and the electrode assembly 201 is accommodated in the housing 202. The housing 202 may be a wall structure arranged at the periphery of the battery cell 20, which can form a cavity for accommodating other components of the battery cell 20 such as the electrode assembly 201 and an electrolyte. The electrode assembly 201, as a component accommodated in the housing 202, is in contact with the electrolyte, and active ions (such as lithium ions) can be conducted between the electrode assembly 201 and the electrolyte.

[0103] The housing 202 includes an end cover 1 and a shell 4. The shell 4 has an opening, and the end cover 1 covers the opening.

[0104] Some embodiments of the present application provide a battery cell 20, such as Figure 4 and Figure 5 As shown, the battery cell 20 includes a housing 202, an electrode assembly 201, a pressure relief member 2 and a protective member 3. The housing 202 forms a receiving space 203. The housing 202 is provided with a through hole 11. The through hole 11 can connect the receiving space 203 with the outside. The electrode assembly 201 is arranged in the receiving space 203. Figure 6 As shown, the pressure relief member 2 blocks the through hole 11 and is connected to the housing 202, and the pressure relief member 2 is provided with a cracking structure 21. Figure 7 The protective member 3 covers the through hole 11 and is located on the side of the housing 202 away from the electrode assembly 201. Figure 8 and Fig. 9 The protective member 3 includes a first portion 31 and a second portion 32 connected to each other, the second portion 32 is arranged along the periphery of the first portion 31 and connected to the housing 202, and the first portion 31 is a transparent structure; continue to refer to Fig.10 The second portion 32 includes a color development area 3211 , and along the axial direction of the through hole 11 , the projection of the color development area 3211 is located outside the projection of the crack structure 21 .

[0105] In the embodiment of the present application, the outer shell 202 of the battery cell 20 may include an end cap 1 and a shell 4, which are sealed and connected to form a receiving space 203 for receiving components such as the electrode assembly 201. Exemplarily, the shell 4 may be a cylindrical structure having an opening at at least one end, and the end cap 1 is sealed to cover the opening, and the end cap 1 and the shell 4 together form a receiving space 203 for receiving components such as the electrode assembly 201 and the electrolyte.

[0106] The through hole 11 can be a hole-like structure opened on the end cover 1 or the shell 4, which can connect the accommodating space 203 surrounded by the outer shell 202 with the outside world, so that the through hole 11 can allow the gas in the accommodating space 203 to exchange with the outside world, so that the through hole 11 can serve as a channel for balancing the pressure in the accommodating space 203 with the external pressure.

[0107] The electrode assembly 201 is immersed in the electrolyte by being disposed in the accommodation space 203. The electrode assembly 201 includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell 20, active ions (such as lithium ions) are intercalated and released back and forth between the positive electrode and the negative electrode.

[0108] The pressure relief member 2 can be a component disposed at the through hole 11 for controlling whether the through hole 11 connects the accommodation space 203 with the outside. The through hole 11 is blocked by the pressure relief member 2 and sealed with the housing 202, so that the communication function of the through hole 11 is controlled by the pressure relief member 2.

[0109] Exemplarily, the pressure relief member 2 may be a sheet-like member, so that the pressure relief member 2 can be conveniently connected to the through hole 11 by covering, so as to achieve the blocking of the through hole 11. The connection between the pressure relief member 2 and the housing 202 may be that the edge portion of the outer periphery of the pressure relief member 2 is sealedly connected to the housing 202 at the outer periphery of the through hole 11. Exemplarily, the pressure relief member 2 may be bonded to the housing 202 by adhesives such as glue, so that the connection between the pressure relief member 2 and the housing 202 is convenient; the pressure relief member 2 may also be welded to the housing 202, so that the connection between the pressure relief member 2 and the housing 202 not only has good connection strength, but also has good sealing.

[0110] The cracking structure 21 may be a portion of the pressure relief member 2 that can be broken. When the cracking structure 21 is broken, the pressure relief member 2 stops blocking the through hole 11, and the through hole 11 connects the accommodation space 203 with the outside. The structural strength of the cracking structure 21 is lower than the structural strength of other portions of the pressure relief member 2, so that when the pressure in the accommodation space 203 reaches or exceeds the first preset value, the cracking structure 21 can be broken, connecting the accommodation space 203 with the outside, and the pressure in the accommodation space 203 can be released.

[0111] For example, the strength of the material at the crack structure 21 may be lower than the strength of the material at other parts, or the thickness at the crack structure 21 may be smaller than the thickness at other parts.

[0112] The protective member 3 may be a component for covering and protecting the through hole 11, which is used to reduce the entry of external dirt into the through hole 11, which is beneficial to improving the reliability of the pressure relief member 2 and reducing the entry of dirt into the accommodating space 203. The protective member 3 covers the through hole 11 and is located on the side of the housing 202 away from the electrode assembly 201, so that the protective member 3 covers the through hole 11 from the side of the housing 202 away from the electrode assembly 201, reducing the possibility of dirt entering the through hole 11.

[0113] The first portion 31 and the second portion 32 may be two interconnected portions of the protective member 3. By arranging the second portion 32 along the outer circumference of the first portion 31, the second portion 32 is arranged around at least a portion of the outer circumference of the first portion 31, so that the second portion 32 is located at an edge portion of the protective member 3. By connecting the second portion 32 to the housing 202, the protective member 3 can be connected to the housing 202 and firmly cover the through hole 11.

[0114] The color region 3211 may be a non-transparent region 3212 in the second portion 32, which is opaque in color. By providing the color region 3211 in the second portion 32, the assembler can easily identify whether the second portion 32 (protective member 3) is provided at the through hole 11 by observation or equipment, which is conducive to reducing the possibility of missing the protective member 3 at the through hole 11, thereby reducing the possibility of dirt entering the through hole 11, and is conducive to improving the reliability of the battery cell 20.

[0115] By setting the first part 31 as a transparent structure, and making the projection of the color display area 3211 in the axial direction of the through hole 11 located outside the projection of the crack structure 21 in the axial direction of the through hole 11, the middle part of the protective member 3 is transparent, the edge part has the color display area 3211, and the color display area 3211 is not easy to block the crack structure 21 of the pressure relief member 2, so that the assembler can easily detect whether the crack structure 21 has defects through observation or equipment, which is convenient for timely identification of the defective pressure relief member 2, reducing the possibility of a defective pressure relief member 2 being provided in the battery cell 20, which is beneficial to improving the reliability of the battery cell 20.

[0116] Exemplarily, the color of the color display area 3211 may be any one of blue, red, and yellow, so that the assembler can easily identify whether the second portion 32 (protective member 3) is provided at the through hole 11 by observation or equipment.

[0117] In some embodiments, the color development area 3211 can be formed by adding pigments of corresponding colors to the material in the second portion 32 .

[0118] In the above structure, since the first part 31 in the protective member 3 is a transparent structure, the second part 32 including the color display area 3211 is arranged along the outer periphery of the first part 31, and the axial projection of the color display area 3211 in the through hole 11 is located outside the axial projection of the crack structure 21 in the through hole 11, the set color display area 3211 is convenient for distinguishing whether the protective member 3 is connected to the through hole 11, reducing the omission of the protective member 3, and is not easy to block the crack structure 21, which is convenient for detecting whether the crack structure 21 has defects. This not only reduces the possibility of dirt entering the through hole 11, but also helps to reduce the possibility of a defective pressure relief member 2 being provided in the battery cell 20, so that the battery cell 20 has higher reliability.

[0119] In some embodiments, continue to refer to Fig.11 and Fig.12 The second portion 32 further includes a transparent region 3212 disposed along the inner periphery of the color development region 3211 , and the transparent region 3212 is connected to the outer periphery of the first portion 31 .

[0120] The transparent area 3212 may be a transparent part in the second part 32, which is opaque in color. By providing the transparent area 3212 in the second part 32 and connecting the transparent area 3212 to the periphery of the first part 31, the area of ​​the second part 32 can be increased and it is not easy to block the crack structure 21, which is beneficial to increase the area of ​​the edge part of the protective member 3 for connecting with the housing 202 (the second part 32), and is beneficial to improve the firmness of the connection between the protective member 3 and the housing 202.

[0121] In some embodiments, a first adhesive layer 323 is disposed on the side of the second portion 32 facing the housing 202 , and the second portion 32 is bonded to the housing 202 through the first adhesive layer 323 .

[0122] The first adhesive layer 323 may be a structural layer having an adhesive property, which can connect two components by bonding.

[0123] By providing the first adhesive layer 323 on the side of the second portion 32 facing the housing 202 , the second portion 32 of the protective member 3 can be bonded to the housing 202 through the first adhesive layer 323 , so that the protective member 3 can be conveniently connected to the housing 202 .

[0124] In some embodiments, the second part 32 includes a bonding area 321 and a detachment area 322 arranged along the circumference of the first part 31, the bonding area 321 is provided with a first bonding layer 323, and the detachment area 322 is not provided with the first bonding layer 323, and along the radial direction of the through hole 11, the detachment area 322 is connected between the edge of the first part 31 and the edge of the protective member 3.

[0125] The bonding area 321 and the detachment area 322 may be two areas arranged circumferentially in the second portion 32 , wherein the bonding area 321 is an area in the second portion 32 where the first bonding layer 323 is provided, and the bonding area 321 is an area in the second portion 32 where the first bonding layer 323 is not provided.

[0126] The detachment zone 322 is connected between the edge of the first part 31 and the edge of the protective member 3. It can be that there is a detachment zone 322 without the first adhesive layer 323 between the edge of the first part 31 and the edge of the protective member 3. The detachment zone 322 is not connected to the outer shell 202, so that the crack structure 21 is broken. When the battery cell 20 is depressurized, the discharged material can be discharged to the outside through the gap between the through hole 11, the detachment zone 322 and the outer shell 202, so that the pressure relief of the battery cell 20 is smoother.

[0127] In some embodiments, a second adhesive layer 311 is disposed on the side of the first portion 31 facing the housing 202 , and the second adhesive layer 311 is connected to the first adhesive layer 323 .

[0128] The second adhesive layer 311 may be a structural layer with adhesive properties, which can connect two components by bonding.

[0129] A second adhesive layer 311 is provided on the side of the first part 31 facing the outer shell 202. The second adhesive layer 311 connected to the first adhesive layer 323 is provided on the edge portion of the side of the first part 31 facing the outer shell 202, so that even if the protective part 3 is deflected during the process of being attached to the outer shell 202, the protective part 3 can be adhered to the outer shell 202 through the second adhesive layer 311, thereby reducing the possibility of the protective part 3 falling off when it is deflected.

[0130] Exemplarily, the second adhesive layer 311 may be in the shape of a ring extending along the circumference of the first portion 31 ; a plurality of second adhesive layers 311 may also be provided, and the plurality of second adhesive layers 311 are spaced apart along the circumference of the first portion 31 .

[0131] In some embodiments, in the axial direction of the through hole 11 , the shortest distance between the projection of the crack structure 21 and the projection of the outer edge of the color development area 3211 is A, and the width of the projection of the color development area 3211 is B, where B<A.

[0132] Since the color developing area 3211 is connected to the edge of the protective member 3, by setting the width of the projection of the color developing area 3211 in the axial direction of the through hole 11 to B, the shortest distance from the projection of the crack structure 21 in the axial direction of the through hole 11 to the projection of the outer edge of the color developing area 3211 is set to A, and B is made less than A, so that the color developing area 3211 is not easy to block the crack structure 21 in the axial direction of the through hole 11.

[0133] In some embodiments, B ≥ 0.4 mm.

[0134] By setting the range of the width B of the projection of the color display area 3211 to B≥0.4mm, the color display area 3211 has a sufficient width, so that the color display area 3211 in the protective member 3 can be easily identified by the assembler through visual inspection or equipment, which is conducive to identifying whether the protective member 3 is provided at the through hole 11.

[0135] In some embodiments, a boss 12 is protruded from one side of the housing 202 away from the electrode assembly 201 . The boss 12 is disposed around the outer circumference of the through hole 11 , and the second portion 32 is connected to the boss 12 .

[0136] The boss 12 may be a structure protruding from a side of the housing 202 away from the electrode assembly 201 , and is used to be connected to the protective member 3 .

[0137] By protruding a boss 12 surrounding the through hole 11 on the side of the housing 202 away from the electrode assembly 201 , it is convenient to connect the second portion 32 to the boss 12 , which is beneficial to improving the assembly efficiency of the battery cell 20 .

[0138] In some embodiments, in the radial direction of the through hole 11 , the width of the boss 12 is C, the width of the second portion 32 is D, and 1.5C≤D≤4C.

[0139] The radial width of the boss 12 in the through hole 11 is set to C, and the radial width of the second part 32 in the through hole 11 is set to D. By making 1.5C≤D≤4C, not only can the second part 32 have sufficient width in the radial direction of the through hole 11 to bond with the boss 12, but it can also reduce the waste of adhesive material caused by the excessive radial width of the second part 32 in the through hole 11, which is beneficial to reducing the cost of the protective member 3.

[0140] In some embodiments, 2C≤D≤3C, illustratively, D=2C, D=2.5C or D=3C, which not only enables the second portion 32 to be well bonded to the boss 12, but also reduces the waste of adhesive material caused by the excessive radial width of the second portion 32 in the through hole 11, which is beneficial to reducing the cost of the protective member 3.

[0141] In some embodiments, the inner circumferential surface of the boss 12 coincides with the inner wall surface of the through hole 11, the pressure relief component 2 is located in the through hole 11 and connected to the inner wall of the through hole 11, and the cracking structure 21 is configured as an annular structure; in the radial direction of the through hole 11, the shortest distance between the cracking structure 21 and the edge of the pressure relief component 2 is F, the width of the boss 12 is C, and 1C≤F≤2.5C.

[0142] By aligning the inner peripheral surface of the boss 12 with the inner wall surface of the through hole 11 , the through hole 11 can be formed by penetrating the boss 12 and the housing 202 , so that the processing of the through hole 11 is convenient.

[0143] By arranging the pressure relief member 2 in the through hole 11 and connecting to the inner wall of the through hole 11 , when the protection member 3 covers the through hole 11 , the protection member 3 and the through hole 11 can be protected.

[0144] By configuring the cracking structure 21 as an annular structure, the relationship between the shortest distance F between the cracking structure 21 and the edge of the pressure relief component 2 in the radial direction of the through hole 11 and the width C of the boss 12 in the radial direction of the through hole 11 is set to C≤F≤2.5C, which not only enables the cracking structure 21 to enclose a sufficient valve opening area, but also reduces the influence of the cracking structure 21 on the connection between the pressure relief component 2 and the inner wall of the through hole 11, which is beneficial to improve the connection strength between the pressure relief component 2 and the inner wall of the through hole 11.

[0145] In some embodiments, 1.2C≤F≤2C, which not only enables the cracking structure 21 to enclose a sufficient valve opening area, but also reduces the impact of the cracking structure 21 on the connection between the pressure relief component 2 and the inner wall of the through hole 11, which is beneficial to improving the connection strength between the pressure relief component 2 and the inner wall of the through hole 11.

[0146] Exemplarily, the protective member 3 is an integrally formed structure.

[0147] The protective member 3 is an integrally formed structure, which may mean that the protective member 3 may be a sheet-like structure integrally formed by a stamping process, so that the protective member 3 is easy to process and form.

[0148] Exemplarily, the rest of the protective member 3 except for the color-developing area 3211 is a transparent structure, so that the assembler can easily detect the components in the through hole 11 by observation or equipment.

[0149] Some embodiments of the present application further provide a battery 100 , which includes a battery cell 20 provided by the above technical solution.

[0150] Some embodiments of the present application further provide an electrical device, which includes the battery 100 provided by the above technical solution, and the battery 100 is used to provide electrical energy.

[0151] Some embodiments of the present application provide a battery cell 20, which includes a shell 202, an electrode assembly 201, a pressure relief member 2 and a protective member 3. The shell 202 forms a accommodating space 203. The shell 202 is provided with a through hole 11, and the through hole 11 can connect the accommodating space 203 with the outside world. The electrode assembly 201 is arranged in the accommodating space 203, the pressure relief member 2 blocks the through hole 11 and is connected to the shell 202, the pressure relief member 2 is provided with a cracking structure 21, and the protective member 3 covers the through hole 11 and is located on the side of the shell 202 away from the electrode assembly 201. The protective member 3 includes a first portion 31 and a second portion 32 arranged along the outer periphery of the first portion 31, the second portion 32 includes a bonding area 321 and a detachment area 322 arranged along the circumference of the first portion 31, the bonding area 321 includes a color development area 3211 and a transparent area 3212 arranged along the inner periphery of the color development area 3211, the bonding area 321 is bonded to the shell 202 through a first bonding layer 323 on the side facing the shell 202, the detachment area 322 is not provided with the first bonding layer 323 on the side facing the shell 202, and along the axial direction of the through hole 11, the projection of the color development area 3211 is located outside the projection of the crack structure 21.

[0152] Since the first part 31 in the protective member 3 is a transparent structure, the second part 32 including the color display area 3211 is arranged along the outer periphery of the first part 31, and the axial projection of the color display area 3211 in the through hole 11 is located outside the axial projection of the crack structure 21 in the through hole 11, the set color display area 3211 is convenient for distinguishing whether the protective member 3 is connected to the through hole 11, reducing the omission of the protective member 3, and is not easy to block the crack structure 21, which is convenient for detecting whether the crack structure 21 has defects. This not only reduces the possibility of dirt entering the through hole 11, but also helps to reduce the possibility of a defective pressure relief member 2 being provided in the battery cell 20, so that the battery cell 20 has higher reliability.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present 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. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A shell, forming a receiving space, wherein the shell is provided with a through hole, and the through hole can connect the receiving space with the outside; An electrode assembly is disposed in the accommodation space; A pressure relief piece, blocking the through hole and connected to the housing, the pressure relief piece being provided with a cracking structure; A protective member covers the through hole and is located on a side of the shell away from the electrode assembly, the protective member includes a first part and a second part that are connected, the second part is arranged along the periphery of the first part and connected to the shell, the first part is a transparent structure; the second part includes a color development area, and along the axial direction of the through hole, the projection of the color development area is located outside the projection of the crack structure.

2. The battery cell according to claim 1, characterized in that: The second portion further includes a transparent area disposed along an inner periphery of the color development area, and the transparent area is connected to an outer periphery of the first portion.

3. The battery cell according to claim 1, characterized in that: A first adhesive layer is provided on the side of the second part facing the shell, and the second part is bonded to the shell through the first adhesive layer.

4. The battery cell according to claim 3, characterized in that: The second part includes a bonding area and a detachment area arranged along the circumference of the first part, the bonding area is provided with the first bonding layer, and the detachment area is not provided with the first bonding layer. Along the radial direction of the through hole, the detachment area is connected between the edge of the first part and the edge of the protective member.

5. The battery cell according to claim 3, characterized in that: A second adhesive layer is provided on the side of the first portion facing the housing, and the second adhesive layer is connected to the first adhesive layer.

6. The battery cell according to claim 3, characterized in that: The color developing area is connected to the edge of the protective member. In the axial direction of the through hole, the shortest distance between the projection of the crack structure and the projection of the outer edge of the color developing area is A. The width of the color developing area projection is B, and B<A.

7. The battery cell according to claim 6, characterized in that: B≥0.4mm.

8. The battery cell according to claim 1, characterized in that: A boss is protruding from one side of the shell away from the electrode assembly. The boss is arranged around the outer periphery of the through hole, and the second part is connected to the boss.

9. The battery cell according to claim 8, characterized in that: In the radial direction of the through hole, the width of the boss is C, the width of the second portion is D, and 1.5C≤D≤4C.

10. The battery cell according to claim 1, characterized in that: The protective member is an integrally formed structure.

11. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 10.

12. An electrical device, characterized in that: Comprising the battery of claim 11, the battery is used to provide electrical energy.

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