Battery monomer, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device, and the battery monomer comprises a shell and an electrode assembly. The shell is provided with a containing cavity, the electrode assembly is contained in the containing cavity, the electrode assembly comprises a first pole piece, an isolating membrane and a second pole piece, and the first pole piece, the isolating membrane and the second pole piece are wound in the winding direction to form a winding main body section of the electrode assembly. The electrode assembly further comprises a first wrapping part, and the first wrapping part is connected with one end, in the winding direction, of the first pole piece, is wound outside the winding body section and wraps at least part of the peripheral side of the winding body section. According to the technical scheme provided by the invention, when the electrode assembly is transferred, the risk that the isolating membrane is scratched by an external part and the pole piece is scratched can be reduced.

Description

Technical Field

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

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also growing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of reliability and service life.

[0003] During the manufacturing process of battery cells, when the electrode assemblies in the battery cells are being transported, external components may scratch the isolation membrane and the pole pieces, thereby reducing the service life and reliability of the battery cells. Utility Model Content

[0004] The embodiments of the present application provide a battery cell, a battery device, and an electrical device, which can reduce the risk of external components scratching the isolation membrane and the electrode sheet during transportation of the electrode assembly.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising a housing and an electrode assembly. The housing has a housing cavity, and the electrode assembly is accommodated in the housing cavity, and the electrode assembly comprises a first pole piece, a separator, and a second pole piece, and the first pole piece, the separator, and the second pole piece are wound along a winding direction to form a winding main body section of the electrode assembly. The electrode assembly also includes a first covering member, which is connected to one end of the first pole piece in the winding direction, and is wound outside the winding main body section, and covers at least part of the outer circumference of the winding main body section.

[0006] In the above technical solution, the electrode assembly also includes a first covering member, which is connected to one end of the first electrode sheet in the winding direction, and is wound outside the winding main section, and covers at least a portion of the outer peripheral side of the winding main section, so that when the outer peripheral side of at least a portion of the winding main section covered by the first covering member moves relative to an external component, the external component must first scratch the first covering member before it can further scratch the isolation membrane and scratch the electrode sheet, thereby reducing the risk of external components scratching the isolation membrane and scratching the electrode sheet when the electrode assembly is transported.

[0007] In some embodiments, the first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, the first covering has a length L1 in the winding direction, the innermost circle of the second pole sheet has a length L in the winding direction, and the thickness C of the wound main body segment in the first direction satisfies 2L+2Cπ≤L1≤2.5L+2.5Cπ, the electrode assembly has a straight area, and the portion of the negative pole sheet located in the straight area and the portion of the positive pole sheet located in the straight area are stacked along the first direction.

[0008] In the above technical scheme, when L1≥2L+2Cπ, the first covering member can continue to wrap around the outer periphery of the winding main section for at least one circle after covering the second pole piece located outside the first pole piece, thereby reducing the risk of external components scratching the isolation membrane and scratching the pole piece when the electrode assembly is transported; when L1≤2.5L+2.5Cπ, the volume of the electrode assembly occupied by the first covering member can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly, thereby increasing the volume of the electrode assembly occupied by the pole piece, thereby increasing the energy density of the battery cell; therefore, when 2L+2Cπ≤L1≤2.5L+2.5Cπ, it is possible to take into account both reducing the risk of external components scratching the isolation membrane and scratching the pole piece when the electrode assembly is transported and increasing the energy density of the battery cell.

[0009] In some embodiments, the first pole piece is a positive pole piece, the second pole piece is a negative pole piece, and along the winding direction, the second pole piece exceeds the connection between the first pole piece and the first covering member.

[0010] In the above technical solution, along the winding direction, the second pole sheet extends beyond the connection between the first pole sheet and the first covering member, that is, along the winding direction, the tail end of the negative pole sheet located at the outermost layer extends beyond the tail end of the positive pole sheet located at the outermost layer, thereby achieving corresponding arrangements of the negative electrode active material on the inner side of the second pole sheet close to the tail end and the positive electrode active material of the positive pole sheet on its inner side, reducing the possibility of lithium deposition in the tail section of the second pole sheet, thereby improving the reliability of the battery cell including the electrode assembly.

[0011] In some embodiments, the first covering member is integrally formed with the first pole piece, and the first covering member is a hollow foil area.

[0012] In the above technical solution, the first covering member and the first pole piece are integrally formed, thereby increasing the stability of the connection between the first covering member and the first pole piece. At the same time, the first covering member is a hollow foil area, so that the thickness of the first covering member is relatively thin. Therefore, when the electrode assembly is transported, the first covering member reduces the risk of external components scratching the isolation membrane and scratching the pole piece while occupying a smaller space. Therefore, under the premise of a certain volume of the electrode assembly, the pole piece can be wound more times, thereby increasing the volume of the electrode assembly occupied by the pole piece, and then increasing the energy density of the battery cell.

[0013] In some embodiments, the first covering member is bonded to one end of the first pole piece.

[0014] In the above technical solution, the first covering member is bonded and fixed to one end of the first electrode sheet, so that the manufacture of the electrode assembly is more convenient and the manufacturing cost can also be reduced.

[0015] In some embodiments, the first covering member is made of one of polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyimide or polyamide-imide.

[0016] In the above technical scheme, polyethylene terephthalate, polyimide, polycarbonate and polyimide or polyamide-imide have the advantages of impact resistance, good puncture resistance, good heat aging resistance, etc., and the first coating is made of one of the above materials so that the first coating also has the advantages of impact resistance, good puncture resistance, good heat aging resistance, etc., thereby reducing the risk of external components scratching the isolation membrane and scratching the electrode sheet during transportation of the electrode assembly.

[0017] In some embodiments, the electrode assembly further includes a second covering member, which is connected to one end of the second pole piece in the winding direction, and is wound outside the winding main section and covers at least a portion of the outer circumference of the winding main section.

[0018] In the above technical solution, the electrode assembly also includes a second covering member, which is connected to one end of the second electrode sheet in the winding direction, and is wound outside the winding main section, and covers at least a portion of the outer peripheral side of the winding main section, so that when the outer peripheral side of at least a portion of the winding main section covered by the second covering member moves relative to an external component, the external component must first scratch the second covering member before it can further scratch the isolation membrane and scratch the electrode sheet, thereby reducing the risk of external components scratching the isolation membrane and scratching the electrode sheet when the electrode assembly is transported.

[0019] In some embodiments, the first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, the second covering has a length L2 in the winding direction, the innermost circle of the second pole sheet has a length L in the winding direction, and the thickness C of the wound main body segment in the first direction satisfies L+Cπ≤L2≤1.25L+1.25Cπ, the electrode assembly has a straight area, and the portion of the negative pole sheet located in the straight area and the portion of the positive pole sheet located in the straight area are stacked along the first direction.

[0020] In the above technical scheme, when L2≥L+Cπ, the second covering can cover the second pole piece located at the outermost circle, thereby reducing the risk of external components scratching the isolation membrane and damaging the pole piece when the electrode assembly is transported; when L2≤1.25L+1.25Cπ, the volume of the electrode assembly occupied by the covering can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly, thereby increasing the volume of the electrode assembly occupied by the pole piece, thereby increasing the energy density of the battery cell; therefore, when L+Cπ≤L2≤1.25L+1.25Cπ, it is possible to take into account both reducing the risk of external components scratching the isolation membrane and damaging the pole piece when the electrode assembly is transported and increasing the energy density of the battery cell.

[0021] In some embodiments, the electrode assembly further includes a third covering member, which is connected to the other end of the first pole piece in the winding direction, is wound within the winding main section, and covers at least a portion of the inner circumference of the winding main section.

[0022] In the above technical solution, the electrode assembly also includes a third covering member, and the first covering member and the third covering member are respectively connected to the two ends of the first electrode sheet in the winding direction, and are wound in the winding main section, and cover at least part of the inner circumference of the winding main section, so that when the inner circumference of at least part of the winding main section covered by the third covering member is detached from the winding needle, the winding needle needs to first scratch the third covering member before it can further scratch the isolation membrane and scratch the electrode sheet, thereby reducing the risk of the winding needle scratching the isolation membrane and scratching the electrode sheet when the electrode assembly is detached from the winding needle.

[0023] In some embodiments, the first pole piece is a positive pole piece, the second pole piece is a negative pole piece, the third covering has a length L3 in the winding direction, and the innermost circle of the second pole piece has a length L in the winding direction, which satisfies 1.5L≤L3≤1.75L.

[0024] In the above technical solution, when L3≥1.5L, the third covering member can cover the second pole sheet located inside the first pole sheet, thereby reducing the risk of the winding needle scratching the isolation membrane and scratching the pole sheet when the electrode assembly is detached from the winding needle, and at the same time can support the innermost circle of the winding main body segment to reduce the risk of the innermost circle of the second pole sheet collapsing inward; when L3≤1.75L, the volume of the electrode assembly occupied by the third covering member can be reduced, so that the pole sheet can be wound more times under the premise of a certain volume of the electrode assembly, thereby increasing the volume of the electrode assembly occupied by the pole sheet, and then increasing the energy density of the battery cell; therefore, when 1.5L≤L3≤1.75L, it can take into account both reducing the risk of the winding needle scratching the isolation membrane and scratching the pole sheet when the electrode assembly is detached from the winding needle and increasing the energy density of the battery cell.

[0025] In some embodiments, the first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, and along the winding direction, a connection between the first pole sheet and the third covering member exceeds the second pole sheet.

[0026] In the above technical solution, along the winding direction, the connection between the first pole sheet and the third covering member exceeds the second pole sheet, that is, along the winding direction, the starting end of the positive pole sheet located in the innermost layer exceeds the starting end of the negative pole sheet located in the innermost layer, so that the negative electrode active material on the outer side surface of the second pole sheet close to the starting end and the positive electrode active material of the positive pole sheet on its outer side are arranged correspondingly, thereby reducing the possibility of lithium deposition at the starting end of the first pole sheet, thereby improving the reliability of the battery cell including the electrode assembly.

[0027] In some embodiments, the electrode assembly further includes a fourth covering member, which is connected to one end of the second pole piece in the winding direction, is wound within the winding main body segment, and covers at least a portion of the inner circumference of the winding main body segment.

[0028] In the above technical solution, the electrode assembly also includes a fourth covering member, which is connected to one end of the second electrode sheet in the winding direction, and is wound in the winding main section, and covers at least a portion of the inner circumference of the winding main section, so that when the inner circumference of at least a portion of the winding main section covered by the fourth covering member is detached from the winding needle, the winding needle needs to first scratch the fourth covering member before it can further scratch the isolation membrane and scratch the electrode sheet, thereby reducing the risk of the winding needle scratching the isolation membrane and scratching the electrode sheet when the electrode assembly is detached from the winding needle.

[0029] In some embodiments, the first pole piece is a positive pole piece, the second pole piece is a negative pole piece, the fourth covering has a length L4 in the winding direction, and the innermost circle of the second pole piece has a length L in the winding direction, satisfying L≤L4≤1.25L.

[0030] In the above technical solution, when L4≥L, the fourth covering member can cover the inner circumference of the starting end of the second pole piece, thereby reducing the risk of the winding needle scratching the isolation membrane and scratching the pole piece when the electrode assembly is detached from the winding needle, and at the same time can support the innermost circle of the winding main section to reduce the risk of the innermost circle of the second pole piece collapsing inward; when L4≤1.25L, the volume of the electrode assembly occupied by the fourth covering member can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly, thereby increasing the volume of the electrode assembly occupied by the pole piece, and then increasing the energy density of the battery cell; therefore, when L≤L4≤1.25L, it can take into account both reducing the risk of the winding needle scratching the isolation membrane and scratching the pole piece when the electrode assembly is detached from the winding needle and increasing the energy density of the battery cell.

[0031] In a second aspect, an embodiment of the present application further provides a battery device, comprising the above-mentioned battery cell.

[0032] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0035] Figure 2 An exploded view of the structure of a battery device provided in some embodiments of the present application;

[0036] Figure 3 An exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0037] Figure 4 A schematic structural diagram of a first electrode assembly provided in some embodiments of the present application;

[0038] Figure 5 A schematic diagram of the structure of a second electrode assembly provided in some embodiments of the present application;

[0039] Figure 6 A schematic structural diagram of a third electrode assembly provided in some embodiments of the present application;

[0040] Figure 7A schematic structural diagram of a fourth electrode assembly provided for some embodiments of the present application.

[0041] Icon: 1000-Vehicle; 100-Battery Device;

[0042] 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-shell; 212-cover; 213-electrode terminal;

[0043] 22-electrode assembly; 22A-straight area; 22B-bending area; 22C-ear; 220-wound main body; 221-first pole piece; 221A-first starting end; 221B-first ending end; 222-second pole piece; 222A-second starting end; 222B-second ending end; 223-isolation film; 224-first covering member; 225-second covering member; 226-third covering member; 227-fourth covering member;

[0044] 200-controller; 300-motor;

[0045] X-first direction; Y-second direction; Q-winding direction; P-winding axis. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0048] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0049] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" 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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0052] The term “plurality” used in this application refers to two or more (including two).

[0053] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0054] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0055] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0056] 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 disposed on at least one surface of the positive electrode current collector.

[0057] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0058] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer 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 a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0059] As an example, 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 may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (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 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, LiMn2O4), 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 )、LiNi 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 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0060] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0061] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0062] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. The composite current collector may include a polymer material base layer 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 a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0063] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0064] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0065] 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.

[0066] 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.

[0067] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical stability and mechanical stability.

[0068] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0069] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0070] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0071] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0072] In some embodiments, the solvent may include 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 may also be an ether solvent. The ether solvent 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, methyltetrahydrofuran, diphenyl ether and crown ether.

[0073] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0074] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0075] 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.

[0076] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON 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.

[0077] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0078] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0079] 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.

[0080] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, in parallel or in mixed connection through a busbar component.

[0085] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, a battery cell assembly may be a battery module, and a battery module is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, a battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0086] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0087] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0088] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0089] As an example, the box body may include a first box body and a second box body. The first box body and the second box body are buckled together to form a closed space inside the box body to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first box body can be a top cover or a bottom plate.

[0090] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0091] As an example, the box body can be used as a part of the chassis structure of the vehicle. For example, the top cover of the box body can become at least a part of the floor of the vehicle, or the frame of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0092] In some embodiments, the battery device refers to an energy storage device, which includes a box body, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, and the like.

[0093] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient. They are an important part of the development of new energy today. The development of battery technology must consider many design factors at the same time, such as performance parameters such as energy density, cycle life, discharge capacity, and charge and discharge rate. In addition, the reliability of the battery must also be considered.

[0094] During the manufacturing process of battery cells, after the electrode assembly is wound and formed, it needs to be transported to the assembly process to be combined with the battery cell shell to form a battery cell. During the transportation of the electrode assembly, external components may scratch the isolation membrane and the electrode sheet, thereby reducing the service life and reliability of the battery cell.

[0095] Based on the above considerations, in order to reduce the risk of external components scratching the isolation membrane and scratching the pole piece during transportation of the electrode assembly. An embodiment of the application provides a battery cell, including a housing and an electrode assembly. The housing has a accommodating cavity, and the electrode assembly is accommodated in the accommodating cavity. The electrode assembly includes a first pole piece, an isolation membrane, and a second pole piece. The first pole piece, the isolation membrane, and the second pole piece are wound along a winding direction to form a winding main body section of the electrode assembly. Among them, the electrode assembly also includes a first covering member, which is connected to one end of the first pole piece in the winding direction, and is wound outside the winding main body section, and covers at least a portion of the outer circumference of the winding main body section.

[0096] In a battery cell of this structure, the electrode assembly also includes a first covering member, which is connected to one end of the first pole piece in the winding direction, and is wound outside the winding main section, and covers at least a portion of the outer peripheral side of the winding main section, so that when the outer peripheral side of at least a portion of the winding main section covered by the first covering member moves relative to an external component, the external component must first scratch the first covering member before it can further scratch the isolation membrane and scratch the pole piece, thereby reducing the risk of external components scratching the isolation membrane and scratching the pole piece when the electrode assembly is transported.

[0097] The battery cell disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cell and battery disclosed in the present application can be used to form the electrical device, which is helpful to alleviate the problem of premature valve opening of the battery cell during use, thereby improving the service life and reliability of the battery cell.

[0098] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0099] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0100] 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 device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may be used as an operating power source or a power source for the vehicle 1000, etc. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0101] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source or a usage 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.

[0102] Please refer to Figure 2 , Figure 2 The structure of the battery device 100 provided in some embodiments of the present application is exploded. The battery device 100 includes a box body 10 and a battery cell 20 . The battery cell 20 is used to be accommodated in the box body 10 .

[0103] The box body 10 is used to provide an assembly space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cell 20. The second box body 12 may be a hollow structure with one end open, and the first box body 11 may be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 may also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0104] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube. Figure 2 In the embodiment, the box body 10 is in the shape of a rectangular parallelepiped.

[0105] In the battery device 100, the battery cell 20 disposed in the box 10 may be one or more. When there are more than one battery cell 20 disposed in the box 10, the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may 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 box 10; of course, the battery device 100 may 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 then the whole is accommodated in the box 10.

[0106] In some embodiments, the battery device 100 may further include other structures. For example, the battery device 100 may further include a busbar component, which is used to connect the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0107] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be in a rectangular parallelepiped, a cylinder, a prism or other shapes. For example, Figure 3 In the figure, the battery cell 20 is a rectangular parallelepiped structure.

[0108] According to some embodiments of the present application, referring to Figure 3 and Figure 4 , Figure 3 This is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application. Figure 4 A schematic diagram of the structure of the first electrode assembly provided for some embodiments of the present application. The embodiment of the present application provides a battery cell 20, including a housing 21 and an electrode assembly 22. The housing 21 has a housing cavity, and the electrode assembly 22 is accommodated in the housing cavity. The electrode assembly 22 includes a first pole piece 221, a separator 223, and a second pole piece 222. The first pole piece 221, the separator 223, and the second pole piece 222 are wound along a winding direction Q to form a winding main body section 220 of the electrode assembly 22. Among them, the electrode assembly 22 also includes a first covering 224, which is connected to one end of the first pole piece 221 in the winding direction Q, and is wound outside the winding main body section 220, and covers at least part of the outer circumference of the winding main body section 220.

[0109] The housing 21 is a component for accommodating the electrode assembly 22 . The housing 21 can also be used to accommodate electrolytes, such as electrolytes. In some embodiments, a receiving cavity is formed inside the housing 21 , and the receiving cavity is used to accommodate the electrode assembly 22 .

[0110] In some embodiments, the material of the shell 21 can be metal or a combination of metal and non-metal. For example, the shell 21 can be made of metal, such as aluminum, copper, iron, aluminum, steel or aluminum alloy; for another example, part of the shell 21 can be made of metal, and the rest can be made of non-metal. For example, the cover 212 of the shell 21 can be made of metal, and the other parts of the shell 21 can be made of non-metallic materials. The shell 21 can be adapted to the shape of the electrode assembly 22. For example, in Figure 3 In the embodiment, the electrode assembly 22 is a rectangular parallelepiped structure, and a housing 21 with a rectangular parallelepiped structure can be selected.

[0111] In some embodiments, the housing 21 includes a shell 211 and a cover 212, and one end of the shell 211 has an opening so that the electrode assembly 22 can be placed inside the shell 211 through the opening. The shell 211 can be made of a metal material, such as aluminum, aluminum alloy or nickel-plated steel. Two electrode terminals 213 are provided on the cover 212. Of the two electrode terminals 213, one is a positive electrode terminal and the other is a negative electrode terminal. The shell 211 can be a rectangular parallelepiped, or a cylinder or an elliptical cylinder. The two electrode terminals 213 can be both provided on the cover 212, or both provided on the shell 211, or one is provided on the cover 212 and the other is provided on the shell 211.

[0112] In some embodiments, the battery cell 20 may also be a soft-pack battery, and the shell 211 is a packaging bag made of aluminum-plastic film material.

[0113] The electrode assembly 22 is disposed inside the housing 21 . The electrode assembly 22 includes two tabs 22C with opposite polarities. The positive electrode terminal is connected to the positive tab 22C of the electrode assembly 22 , and the negative electrode terminal is connected to the negative tab 22C of the electrode assembly 22 .

[0114] The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The shape of the electrode assembly 22 can be cylindrical or flat. Figure 4 In the embodiment, the electrode assembly 22 is flat.

[0115] The first pole piece 221 and the second pole piece 222 are two pole pieces with opposite polarities.

[0116] Exemplarily, if the first electrode piece 221 is a positive electrode piece, the second electrode piece 222 is a negative electrode piece; if the first electrode piece 221 is a negative electrode piece, the second electrode piece 222 is a positive electrode piece.

[0117] The positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0118] As an example, the positive electrode collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is arranged on any one or both of the two opposite surfaces of the positive electrode collector; the negative electrode sheet may include a negative electrode collector and a negative electrode active material arranged on at least one surface of the negative electrode collector.

[0119] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0120] Reference Figure 4 The wound main body section 220 of the electrode assembly 22 may be a wound structure formed by winding a first electrode sheet 221 , a separator 223 , and a second electrode sheet 222 .

[0121] Illustratively, the main material of the isolation film 223 may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0122] Exemplarily, the housing 21 may contain one electrode assembly 22 or multiple electrode assemblies 22 , and the multiple electrode assemblies 22 are stacked along the first direction X.

[0123] The first direction X may be a direction parallel to the thickness of the electrode assembly 22 .

[0124] The first covering member 224 is a component connected to the first tail end 221B of the first electrode plate 221 and used to increase the puncture strength of the outer peripheral side of the electrode assembly 22 .

[0125] The tail end refers to the end of the pole piece located at the outermost circle along the winding direction Q of the electrode assembly 22. For example, along the winding direction Q, the end of the first pole piece 221 away from the winding axis P of the electrode assembly 22 is the first tail end 221B, and the end of the second pole piece 222 away from the winding axis P of the electrode assembly 22 is the second tail end 222B.

[0126] It can be understood that the first covering member 224 can be a metal member or a non-metal member having a puncture strength greater than that of the isolation membrane 223 .

[0127] In this embodiment, the electrode assembly 22 also includes a first covering member 224, which is connected to one end of the first electrode piece 221 in the winding direction Q, and is wound outside the winding main section 220, and covers at least a portion of the outer peripheral side of the winding main section 220, so that when the outer peripheral side of at least a portion of the winding main section 220 covered by the first covering member 224 moves relative to an external component, the external component must first scratch the first covering member 224 before it can further scratch the isolation film 223 and scratch the electrode piece, thereby reducing the risk of external components scratching the isolation film 223 and scratching the electrode piece when the electrode assembly 22 is transported.

[0128] According to some embodiments of the present application, the first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L1 of the first covering member 224 in the winding direction Q, the length L of the innermost circle of the second pole piece 222 in the winding direction Q, and the thickness C of the winding main body segment 220 in the first direction X satisfy 2L+2Cπ≤L1≤2.5L+2.5Cπ, and the electrode assembly 22 has a straight area 22A, and the portion of the negative pole piece located in the straight area 22A and the portion of the positive pole piece located in the straight area 22A are stacked along the first direction X.

[0129] The electrode assembly 22 includes a straight region 22A and two bending regions 22B, wherein the bending region 22B is located at one end of the straight region in the second direction Y, and each bending region 22B has an arc surface. The electrode assembly 22 can be directly wound into a flat shape, or it can be wound into a circular or elliptical shape and then compacted in the middle to form a straight region in the middle of the electrode assembly 22.

[0130] The first pole piece 221 and the second pole piece 222 are straight in the straight region 22A and are bent in the bent region 22B.

[0131] It can be understood that in order to reduce lithium plating near the starting end of the positive electrode sheet, during the winding process of the electrode assembly 22, the negative electrode sheet can be rolled in first so that the starting end of the negative electrode sheet (i.e., the second starting end 222A of the second electrode sheet 222) is closer to the winding axis P.

[0132] The starting end refers to the end of the electrode sheet located at the innermost circle along the winding direction Q of the electrode assembly 22. For example, along the winding direction Q, the end of the first electrode sheet 221 close to the winding axis P of the electrode assembly 22 is the first starting end 221A, and the end of the second electrode sheet 222 close to the winding axis P of the electrode assembly 22 is the second starting end 222A.

[0133] The length L1 of the first covering member 224 in the winding direction Q may be 2L+2Cπ, 2.1L+2.1Cπ, 2.2L+2.2Cπ, 2.3L+2.3Cπ, 2.4L+2.4Cπ or 2.5L+2.5Cπ, etc.

[0134] In the present embodiment, when L1≥2L+2Cπ, the first covering member 224 can continue to wrap at least one circle around the outer periphery of the winding main body section 220 after covering the second pole piece 222 located outside the first pole piece 221, thereby reducing the risk of external components scratching the isolation membrane 223 and damaging the pole piece when the electrode assembly 22 is transported; when L1≤2.5L+2.5Cπ, the volume of the electrode assembly 22 occupied by the first covering member 224 can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly 22, thereby increasing the volume of the electrode assembly 22 occupied by the pole piece, thereby increasing the energy density of the battery cell 20; therefore, when 2L+2Cπ≤L1≤2.5L+2.5Cπ, it is possible to take into account both reducing the risk of external components scratching the isolation membrane 223 and damaging the pole piece when the electrode assembly 22 is transported and increasing the energy density of the battery cell 20.

[0135] According to some embodiments of this application, please refer to Figure 4 The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, and along the winding direction Q, the second pole piece 222 exceeds the connection between the first pole piece 221 and the first covering member 224 .

[0136] Along the winding direction Q, the second pole piece 222 extends beyond the connection between the first pole piece 221 and the first covering member 224, that is, the second tail end 222B extends beyond the first tail end 221B, that is, the second tail end 222B is farther away from the winding axis P of the electrode assembly 22 than the first tail end 221B, thereby achieving a corresponding arrangement of the positive active material of the positive electrode active area of ​​the first pole piece 221 coated with the positive electrode active material and the positive active material of the outer side surface of the first tail end 221B and the negative active material of the second pole piece 222 outside it, thereby reducing the possibility of lithium deposition at the first tail end 221B, and thereby enabling the battery cell 20 including the electrode assembly 22 to have better safety performance during use.

[0137] In this embodiment, along the winding direction Q, the second pole sheet 222 extends beyond the connection between the first pole sheet 221 and the first covering member 224, that is, along the winding direction Q, the second tail end 222B of the negative pole sheet located at the outermost layer extends beyond the first tail end 221B of the positive pole sheet located at the outermost layer, thereby achieving the corresponding arrangement of the negative electrode active material on the inner side of the second pole sheet 222 close to the second tail end 222B and the positive electrode active material of the positive pole sheet on its inner side, reducing the possibility of lithium deposition in the tail section of the second pole sheet 222, thereby improving the reliability of the battery cell 20 including the electrode assembly 22.

[0138] According to some embodiments of the present application, the first covering member 224 and the first pole piece 221 are integrally formed, and the first covering member 224 is a hollow foil area.

[0139] The empty foil area means that the surfaces on both sides of the current collector along its thickness direction are neither coated with active materials nor treated with other coatings or films, and the surface of the current collector is directly exposed.

[0140] In this embodiment, the first covering 224 and the first pole piece 221 are integrally formed, thereby increasing the stability of the connection between the first covering 224 and the first pole piece 221. At the same time, the first covering 224 is a hollow foil area, so that the thickness of the first covering 224 is relatively thin. Therefore, when the electrode assembly 22 is transported, the first covering 224 reduces the risk of external components scratching the isolation film 223 and scratching the pole piece while occupying a smaller space. Therefore, under the premise of a certain volume of the electrode assembly 22, the pole piece can be wound more times, thereby increasing the volume of the electrode assembly 22 occupied by the pole piece, and then increasing the energy density of the battery cell 20.

[0141] According to some embodiments of the present application, the first covering member 224 is bonded to one end of the first pole piece 221 .

[0142] In this embodiment, the first covering member 224 is bonded and fixed to one end of the first electrode sheet 221 , so that the manufacturing of the electrode assembly 22 is more convenient and the manufacturing cost can also be reduced.

[0143] According to some embodiments of the present application, the first covering member 224 is made of one of polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyimide or polyamide-imide.

[0144] Polyethylene terephthalate is also called PET, polytetrafluoroethylene is also called PTFE, polycarbonate is also called PC, polyimide is also called PI, and polyamide-imide is also called PAI.

[0145] In this embodiment, polyethylene terephthalate, polyimide, polycarbonate and polyimide or polyamide-imide have the advantages of good impact resistance, good puncture resistance, good heat aging resistance, etc., and the first covering member 224 is made of one of the above materials. The first covering member 224 also has the advantages of good impact resistance, good puncture resistance, good heat aging resistance, etc., thereby reducing the risk of external components scratching the isolation membrane 223 and scratching the electrode sheet when the electrode assembly 22 is transported.

[0146] According to some embodiments of this application, please refer to Figure 5 , Figure 5 A schematic diagram of the structure of a second electrode assembly provided in some embodiments of the present application. The electrode assembly 22 further includes a second covering member 225, which is connected to one end of the second electrode sheet 222 in the winding direction Q, and is wound outside the winding main body section 220, and covers at least a portion of the outer circumference of the winding main body section 220.

[0147] The second covering member 225 is a component connected to the second tail end 222B of the second electrode sheet 222 and used for increasing the puncture strength of the outer peripheral side of the electrode assembly 22 .

[0148] It can be understood that the second covering member 225 can be a metal member or a non-metal member having a puncture strength greater than that of the isolation membrane 223 .

[0149] In this embodiment, the electrode assembly 22 also includes a second covering member 225, which is connected to one end of the second electrode piece 222 in the winding direction Q, and is wound outside the winding main section 220, and covers at least a portion of the outer peripheral side of the winding main section 220, so that when the outer peripheral side of at least a portion of the winding main section 220 covered by the second covering member 225 moves relative to an external component, the external component must first scratch the second covering member 225 before it can further scratch the isolation film 223 and scratch the electrode piece, thereby reducing the risk of external components scratching the isolation film 223 and scratching the electrode piece when the electrode assembly 22 is transported.

[0150] According to some embodiments of this application, please refer to Figure 5 , the first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L2 of the second covering member 225 in the winding direction Q, the length L of the innermost circle of the second pole piece 222 in the winding direction Q, the thickness C of the winding main body segment 220 in the first direction X, satisfying L+Cπ≤L2≤1.25L+1.25Cπ, the electrode assembly 22 has a straight area 22A, the portion of the negative pole piece located in the straight area 22A and the portion of the positive pole piece located in the straight area 22A are stacked along the first direction X.

[0151] The length L2 of the second covering member 225 in the winding direction Q may be 1L+1Cπ, 1.05L+1.05Cπ, 1.1L+1.1Cπ, 1.15L+1.15Cπ, 1.2L+1.2Cπ or 1.25L+1.25Cπ, etc.

[0152] In the present embodiment, when L2≥L+Cπ, the second covering 225 can cover the second pole piece 222 located at the outermost circle, thereby reducing the risk of external components scratching the isolation membrane 223 and damaging the pole piece when the electrode assembly 22 is transported; when L2≤1.25L+1.25Cπ, the volume of the electrode assembly 22 occupied by the covering can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly 22, thereby increasing the volume of the electrode assembly 22 occupied by the pole piece, thereby increasing the energy density of the battery cell 20; therefore, when L+Cπ≤L2≤1.25L+1.25Cπ, it is possible to take into account both reducing the risk of external components scratching the isolation membrane 223 and damaging the pole piece when the electrode assembly 22 is transported and increasing the energy density of the battery cell 20.

[0153] According to some embodiments of this application, please refer to Figure 6 , Figure 6 A schematic diagram of the structure of a third electrode assembly provided in some embodiments of the present application. The electrode assembly 22 further includes a third covering member 226, which is connected to the other end of the first electrode sheet 221 in the winding direction Q, and is wound inside the winding main body section 220, and covers at least a portion of the inner circumference of the winding main body section 220.

[0154] The third covering member 226 is a component connected to the first starting end 221A of the first electrode plate 221 and used to increase the puncture strength of the inner circumference of the electrode assembly 22 .

[0155] It can be understood that the third covering member 226 can be a metal member or a non-metal member having a puncture strength greater than that of the isolation membrane 223 .

[0156] In this embodiment, the electrode assembly 22 also includes a third covering member 226. The first covering member 224 and the third covering member 226 are respectively connected to the two ends of the first electrode piece 221 in the winding direction Q, and are wound in the winding main section 220, and cover at least a portion of the inner circumference of the winding main section 220, so that when at least a portion of the inner circumference of the winding main section 220 covered by the third covering member 226 is detached from the winding needle, the winding needle needs to first scratch the third covering member 226 before it can further scratch the isolation film 223 to scratch the electrode piece, thereby reducing the risk of the winding needle scratching the isolation film 223 and scratching the electrode piece when the electrode assembly 22 is detached from the winding needle.

[0157] According to some embodiments of this application, please refer to Figure 6 The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L3 of the third covering member 226 in the winding direction Q, and the length L of the innermost circle of the second pole piece 222 in the winding direction Q satisfy 1.5L≤L3≤1.75L.

[0158] The length L3 of the third covering member 226 in the winding direction Q may be 1.5L, 1.55L, 1.6L or 1.75L, etc.

[0159] In the present embodiment, when L3≥1.5L, the third covering member 226 can cover the second pole piece 222 located inside the first pole piece 221, thereby reducing the risk of the winding needle cutting through the isolation membrane 223 and scratching the pole piece when the electrode assembly 22 is detached from the winding needle, and at the same time can support the innermost circle of the winding main body section 220 to reduce the risk of the innermost circle of the second pole piece 222 collapsing inwardly; when L3≤1.75L, the volume of the electrode assembly 22 occupied by the third covering member 226 can be reduced, thereby enabling the pole piece to be wound more times under the premise of a certain volume of the electrode assembly 22, thereby increasing the volume of the electrode assembly 22 occupied by the pole piece, and further increasing the energy density of the battery cell 20; therefore, when 1.5L≤L3≤1.75L, it can take into account both reducing the risk of the winding needle cutting through the isolation membrane 223 and scratching the pole piece when the electrode assembly 22 is detached from the winding needle and increasing the energy density of the battery cell 20.

[0160] According to some embodiments of the present application, referring to Figure 6 The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, and along the winding direction Q, the connection between the first pole piece 221 and the third covering member 226 exceeds the second pole piece 222 .

[0161] Along the winding direction Q, the connection between the first pole piece 221 and the third covering member 226 exceeds the second pole piece 222, that is, the first starting end 221A exceeds the second starting end 222A, that is, the first starting end 221A is farther away from the winding axis P of the electrode assembly 22 relative to the second starting end 222A, thereby achieving the corresponding arrangement of the positive electrode active material of the positive electrode active area of ​​the first pole piece 221 coated with the positive electrode active material and the negative electrode active material of the second pole piece 222 inside it, thereby reducing the possibility of lithium deposition at the first starting end 221A, and thereby making the battery cell 20 including the electrode assembly 22 have better safety performance during use.

[0162] In this embodiment, along the winding direction Q, the connection between the first pole sheet 221 and the third covering member 226 exceeds the second pole sheet 222, that is, along the winding direction Q, the first starting end 221A of the positive pole sheet located in the innermost layer exceeds the second starting end 222A of the negative pole sheet located in the innermost layer, so that the negative electrode active material on the outer side surface of the second pole sheet 222 close to the second starting end 222A corresponds to the positive electrode active material of the positive pole sheet on its outer side, thereby reducing the possibility of lithium deposition at the starting end of the first pole sheet 221, thereby improving the reliability of the battery cell 20 including the electrode assembly 22.

[0163] According to some embodiments of this application, please refer to Figure 7 , Figure 7A schematic diagram of the structure of a fourth electrode assembly provided in some embodiments of the present application. The electrode assembly 22 further includes a fourth covering member 227, which is connected to one end of the second electrode sheet 222 in the winding direction Q, and is wound inside the winding main body section 220, and covers at least a portion of the inner circumference of the winding main body section 220.

[0164] The fourth covering member 227 is a component connected to the second starting end 222A of the second electrode plate 222 and is used to increase the puncture strength of the inner circumference of the electrode assembly 22 .

[0165] It can be understood that the fourth covering member 227 can be a metal member or a non-metal member having a puncture strength greater than that of the isolation membrane 223 .

[0166] In this embodiment, the electrode assembly 22 also includes a fourth covering member 227, which is connected to one end of the second electrode piece 222 in the winding direction Q, and is wound in the winding main section 220, and covers at least a portion of the inner circumference of the winding main section 220, so that when at least a portion of the inner circumference of the winding main section 220 covered by the fourth covering member 227 is detached from the winding needle, the winding needle needs to first scratch the fourth covering member 227 before it can further scratch the isolation film 223 and scratch the electrode piece, thereby reducing the risk of the winding needle scratching the isolation film 223 and scratching the electrode piece when the electrode assembly 22 is detached from the winding needle.

[0167] According to some embodiments of the present application, the first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L4 of the fourth covering member 227 in the winding direction Q, and the length L of the innermost circle of the second pole piece 222 in the winding direction Q satisfy L≤L4≤1.25L.

[0168] The length L4 of the third covering member 226 in the winding direction Q may be L, 1.05L, 1.1L, 1.15L, 1.2L or 1.25L, etc.

[0169] In the present embodiment, when L4≥L, the fourth covering member 227 can cover the inner circumference of the starting end of the second pole piece 222, thereby reducing the risk of the winding needle cutting through the isolation membrane 223 and scratching the pole piece when the electrode assembly 22 is detached from the winding needle, and at the same time can support the innermost circle of the winding main body section 220 to reduce the risk of the innermost circle of the second pole piece 222 collapsing inwardly; when L4≤1.25L, the volume of the electrode assembly 22 occupied by the fourth covering member 227 can be reduced, so that the pole piece can be wound more times under the premise of a certain volume of the electrode assembly 22, thereby increasing the volume of the electrode assembly 22 occupied by the pole piece, and then increasing the energy density of the battery cell 20; therefore, when L≤L4≤1.25L, it can take into account both reducing the risk of the winding needle cutting through the isolation membrane 223 and scratching the pole piece when the electrode assembly 22 is detached from the winding needle and increasing the energy density of the battery cell 20.

[0170] In some embodiments, see Figure 2 As shown, the battery device 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0171] Optionally, the box body 10 may include a first box body 11 and a second box body 12 , the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20 .

[0172] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures both with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0173] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a cuboid. Figure 2 In the embodiment, the box body 10 is a rectangular parallelepiped structure.

[0174] Optionally, the number of battery cells 20 disposed in the box body 10 may be one or more. Figure 2 In the embodiment, a plurality of battery cells 20 are arranged in the box 10 of the battery device 100, and the plurality of battery cells 20 can be connected in series, in parallel or in a mixed connection. The mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery device 100 can also be a battery module formed by first connecting the plurality of battery cells 20 in series, in parallel or in a mixed connection, and then the plurality of battery modules are connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the box 10.

[0175] The battery device 100 may further include other structures. For example, the battery device 100 may further include a busbar component, which connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0176] It should be noted that, in some embodiments, the battery device 100 may not be provided with a box 10, and the battery device 100 includes a plurality of battery cells 20, and the battery device 100 composed of a plurality of battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the plurality of battery cells 20. In other words, the box 10 can be used as a part of the electrical device. Taking the vehicle 1000 as an example of the electrical device, the box 10 can be used as a part of the chassis structure of the vehicle 1000, for example, a part of the box 10 can become at least a part of the floor of the vehicle 1000, or a part of the box 10 can become at least a part of the crossbeam and longitudinal beam of the vehicle 1000.

[0177] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery cell 20 or the battery device 100 of any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0178] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 or the battery device 100 .

[0179] According to some embodiments of the present application, see Figures 3 to 7 As shown, the present application provides a battery cell 20, including a housing 21 and an electrode assembly 22. The housing 21 has a housing cavity, and the electrode assembly 22 is accommodated in the housing cavity. The electrode assembly 22 includes a first pole piece 221, a separator 223, and a second pole piece 222. The first pole piece 221, the separator 223, and the second pole piece 222 are wound along a winding direction Q to form a winding main body section 220 of the electrode assembly 22. Among them, the electrode assembly 22 also includes a first covering member 224, which is connected to one end of the first pole piece 221 in the winding direction Q, and is wound outside the winding main body section 220, and covers at least part of the outer peripheral side of the winding main body section 220.

[0180] The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L1 of the first covering member 224 in the winding direction Q, the length L of the innermost circle of the second pole piece 222 in the winding direction Q, and the thickness C of the winding main body segment 220 in the first direction X satisfy 2L+2Cπ≤L1≤2.5L+2.5Cπ, and the electrode assembly 22 has a straight area 22A, and the portion of the negative pole piece located in the straight area 22A and the portion of the positive pole piece located in the straight area 22A are stacked along the first direction X.

[0181] The first pole piece 221 is a positive pole piece, and the second pole piece 222 is a negative pole piece. Along the winding direction Q, the second pole piece 222 exceeds the connection between the first pole piece 221 and the first covering member 224 .

[0182] In some embodiments, the first covering member 224 and the first pole piece 221 are integrally formed, and the first covering member 224 is a hollow foil area.

[0183] In other embodiments, the first covering member 224 is bonded to one end of the first pole piece 221 , and the first covering member 224 is made of at least one of polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyimide or polyamide-imide.

[0184] The electrode assembly 22 further includes a second covering member 225 , which is connected to one end of the second electrode sheet 222 in the winding direction Q, and is wound outside the winding main body section 220 , and covers at least a portion of the outer circumference of the winding main body section 220 .

[0185] The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L2 of the second covering member 225 in the winding direction Q, the length L of the innermost circle of the second pole piece 222 in the winding direction Q, and the thickness C of the winding main body segment 220 in the first direction X satisfy L+Cπ≤L2≤1.25L+1.25Cπ, and the electrode assembly 22 has a straight area 22A, and the portion of the negative pole piece located in the straight area 22A and the portion of the positive pole piece located in the straight area 22A are stacked along the first direction X.

[0186] The electrode assembly 22 further includes a third covering member 226 , which is connected to the other end of the first electrode sheet 221 in the winding direction Q, and is wound inside the winding main section 220 , and covers at least a portion of the inner circumference of the winding main section 220 .

[0187] The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L3 of the third covering member 226 in the winding direction Q, and the length L of the innermost circle of the second pole piece 222 in the winding direction Q satisfy 1.5L≤L3≤1.75L.

[0188] The first pole piece 221 is a positive pole piece, and the second pole piece 222 is a negative pole piece. Along the winding direction Q, the connection between the first pole piece 221 and the third covering member 226 exceeds the second pole piece 222 .

[0189] The electrode assembly 22 further includes a fourth covering member 227 , which is connected to one end of the second electrode sheet 222 in the winding direction Q, and is wound inside the winding main section 220 , and covers at least a portion of the inner circumference of the winding main section 220 .

[0190] The first pole piece 221 is a positive pole piece, the second pole piece 222 is a negative pole piece, the length L4 of the fourth covering member 227 in the winding direction Q, and the length L of the innermost circle of the second pole piece 222 in the winding direction Q satisfy L≤L4≤1.25L.

[0191] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0192] The above embodiments are only used to illustrate the technical solution of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving cavity; An electrode assembly is accommodated in the accommodation cavity, the electrode assembly comprising a first pole piece, a separator and a second pole piece, the first pole piece, the separator and the second pole piece are wound along a winding direction to form a winding main body section of the electrode assembly; The electrode assembly further includes a first covering member, which is connected to one end of the first electrode sheet in the winding direction, and is wound outside the winding main section and covers at least a portion of the outer circumference of the winding main section.

2. The battery cell according to claim 1, characterized in that: The first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, the first covering member has a length L1 in the winding direction, the innermost circle of the second pole sheet has a length L in the winding direction, and the thickness C of the winding main body segment in the first direction satisfies 2L+2Cπ≤L1≤2.5L+2.5Cπ, the electrode assembly has a straight area, and the portion of the negative pole sheet located in the straight area and the portion of the positive pole sheet located in the straight area are stacked along the first direction.

3. The battery cell according to claim 1, characterized in that: The first pole piece is a positive pole piece, the second pole piece is a negative pole piece, and along the winding direction, the second pole piece exceeds the connection between the first pole piece and the first covering member.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The first covering member is integrally formed with the first pole piece, and the first covering member is a hollow foil area.

5. The battery cell according to any one of claims 1 to 3, characterized in that: The first covering member is bonded to one end of the first pole piece.

6. The battery cell according to claim 5, characterized in that: The first covering member is made of one of polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyimide or polyamide-imide.

7. The battery cell according to claim 1, characterized in that: The electrode assembly further includes a second covering member, which is connected to one end of the second pole piece in the winding direction, is wound outside the winding main section, and covers at least a portion of the outer circumference of the winding main section.

8. The battery cell according to claim 7, characterized in that: The first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, the second covering has a length L2 in the winding direction, the innermost circle of the second pole sheet has a length L in the winding direction, and the thickness C of the winding main body segment in the first direction satisfies L+Cπ≤L2≤1.25L+1.25Cπ, and the electrode assembly has a straight area, and the portion of the negative pole sheet located in the straight area and the portion of the positive pole sheet located in the straight area are stacked along the first direction.

9. The battery cell according to claim 1, characterized in that: The electrode assembly further includes a third covering member, which is connected to the other end of the first electrode sheet in the winding direction, is wound inside the winding main section, and covers at least a portion of the inner circumference of the winding main section.

10. The battery cell according to claim 9, characterized in that: The first pole piece is a positive pole piece, the second pole piece is a negative pole piece, the length L3 of the third covering member in the winding direction, and the length L of the innermost circle of the second pole piece in the winding direction satisfy 1.5L≤L3≤1.75L.

11. The battery cell according to claim 9, characterized in that: The first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, and along the winding direction, a connection between the first pole sheet and the third covering member exceeds the second pole sheet.

12. The battery cell according to claim 1, characterized in that: The electrode assembly further includes a fourth covering member, which is connected to one end of the second pole piece in the winding direction, is wound in the winding main body section, and covers at least a portion of the inner circumference of the winding main body section.

13. The battery cell according to claim 12, characterized in that: The first pole piece is a positive pole piece, the second pole piece is a negative pole piece, the fourth covering member has a length L4 in the winding direction, and the innermost circle of the second pole piece has a length L in the winding direction, which satisfies L≤L4≤1.25L.

14. A battery device, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 13.

15. An electrical device, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 13, wherein the battery cell is used to provide electric energy.

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