Battery cell, battery device, and electric device

Abstract

A battery cell, a battery device, and an electrical device are provided. The battery cell includes an electrode assembly and a finishing adhesive. The electrode assembly includes a first electrode, a separator, and a second electrode, which are wound together. The first electrode includes a first segment and a second segment connected together, arranged sequentially along the winding direction. The second segment is the portion of the first electrode that extends beyond the winding end of the second electrode. The connection point between the first segment and the second segment is located outside the winding end of the second electrode. The finishing adhesive is disposed on the outer periphery of the electrode assembly and has a first end and a second end in its circumferential direction, both located outside the second segment. By positioning the first and second ends outside the second segment, when particulate matter penetrates the electrode assembly from the area between the first and second ends, the particulate matter must penetrate at least four layers of separator, one layer of the first segment, and one layer of the second segment to cause a short circuit, thus increasing the reliability of the battery cell.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability also needs to be considered. However, current battery reliability is relatively poor. Summary of the Invention

[0003] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to improve the problem of poor battery reliability in related technologies.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including an electrode assembly and a finishing adhesive. The electrode assembly includes a first electrode, a separator, and a second electrode. The first electrode and the second electrode have opposite polarities. The first electrode, the separator, and the second electrode are wound together. The first electrode includes a first segment and a second segment connected together. Along the winding direction of the electrode assembly, the first segment and the second segment are arranged sequentially. The second segment is the portion of the first electrode that extends beyond the winding end of the second electrode. The connection position of the first segment and the second segment is located outside the winding end of the second electrode. The finishing adhesive is disposed on the outer periphery of the electrode assembly. The finishing adhesive has a first end and a second end in its circumferential direction. Both the first end and the second end are located outside the second segment.

[0005] In the above technical solution, by placing the finishing adhesive on the outer periphery of the electrode assembly, not only can the winding and finishing portion of the electrode assembly be fixed, maintaining the shape and structure of the electrode assembly, but it can also, to a certain extent, prevent particulate matter from piercing the separator, the first electrode, and the second electrode, reducing the risk of short circuits. By placing the first and second ends on the outside of the second section, when particulate matter pierces the electrode assembly from the area between the first and second ends, the particulate matter needs to pierce at least four layers of separator, one layer of the first section, and one layer of the second section before a short circuit can occur, which helps to improve the reliability of the battery cell.

[0006] As an optional technical solution in this application embodiment, the first end and the second end are spaced apart along the winding direction of the electrode assembly, and a gap area is formed between the first end and the second end.

[0007] In the above technical solution, by setting the first end and the second end at intervals along the winding direction of the electrode assembly, a gap area is formed between the first end and the second end. In this way, there will be no overlapping area of ​​the finishing adhesive and no step will be formed. When the electrode assembly expands, the electrode assembly is less likely to generate stress concentration, which is beneficial to improving the reliability of the battery cell.

[0008] As an optional technical solution in this application embodiment, along the winding direction of the electrode assembly, the size of the notch area is L1, and the length of the second segment is L2, satisfying: L1 / L2≤0.8.

[0009] In the above technical solution, when L1 / L2≤0.8, the size of the winding method along the electrode assembly in the notch area is smaller, which helps to reduce the risk of particles penetrating the electrode assembly from the notch area and improves the protective effect of the finishing adhesive on the electrode assembly.

[0010] As an optional technical solution in this application embodiment, the length of the second segment along the winding direction of the electrode assembly is L2; ​​the distance between the notch area and the winding end of the first electrode sheet along the winding direction of the electrode assembly is L3, satisfying: 0.1≤L3 / L2≤0.8; and / or the distance between the notch area and the winding end of the second electrode sheet along the winding direction of the electrode assembly is L4, satisfying: 0.1≤L4 / L2≤0.8.

[0011] In the above technical solution, when 0.1≤L3 / L2≤0.8, the distance between the notch area along the winding direction of the electrode assembly and the winding end of the first electrode is moderate, so that the notch area can be stably maintained on the outside of the second section. In this way, particles need to pierce at least four layers of separators, one layer of the first section and one layer of the second section before they may cause a short circuit, which is beneficial to improving the reliability of the battery cell.

[0012] When 0.1≤L4 / L2≤0.8, the distance between the notch area along the winding direction of the electrode assembly and the winding end of the second electrode is moderate, so that the notch area can be stably maintained on the outside of the second section. In this way, particles need to pierce at least four layers of separators, one layer of the first section and one layer of the second section before they may cause a short circuit, which is beneficial to improving the reliability of the battery cell.

[0013] As an optional technical solution in this application embodiment, the finishing adhesive has an overlapping area, which is located on the outside of the second segment.

[0014] In the above technical solution, by making the finishing adhesive have an overlapping area, and placing the overlapping area on the outside of the second section, the finishing adhesive can protect the entire circumference of the electrode assembly, thus providing good protection. Furthermore, for particulate matter to penetrate the electrode assembly through the overlapping area and cause a short circuit, the particulate matter would need to pierce at least two layers of finishing adhesive, four layers of separator, one layer of the first section, and one layer of the second section, resulting in a low risk of short circuit and improving the reliability of the battery cell.

[0015] As an optional technical solution in this application embodiment, the finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a main area covered by the adhesive layer and a first area not covered by the adhesive layer. Along the winding direction of the electrode assembly, the first area is connected to one end of the main area. The end of the main area away from the first area is the first end, and the end of the first area away from the main area is the second end. The first area and a portion of the main area are stacked to form the overlapping area. The portion of the main area located in the overlapping area is located inside the first area.

[0016] In the above technical solution, the first region and a part of the main region are stacked to form an overlapping region. The part of the main region located in the overlapping region is bonded to the electrode assembly, while the part of the first region located in the overlapping region is not bonded to the main region. In this way, when the electrode assembly expands, the first region can quickly separate from the main region, allowing the electrode assembly to expand.

[0017] As an optional technical solution in this application embodiment, the finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a main body area covered by the adhesive layer, a first area not covered by the adhesive layer, and a second area not covered by the adhesive layer. Along the winding direction of the electrode assembly, the first area and the second area are respectively connected to both ends of the main body area. The end of the first area away from the main body area is the second end, and the end of the second area away from the main body area is the first end. The first area and the second area are stacked and form the overlapping area.

[0018] In the above technical solution, the first area and the second area are respectively connected to the two ends of the main body area. Neither the first end nor the second end is covered by the adhesive layer, which helps to reduce the risk of incorrect assembly.

[0019] As an optional technical solution in this application embodiment, the finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a first region and a second region located within the overlapping area. The first region and the second region are overlapped. One end of the first region is the second end, and one end of the second region is the first end. The first region and the second region are connected by the adhesive layer.

[0020] In the above technical solution, the first zone and the second zone are connected by an adhesive layer, which makes it less likely for the one of the first zone and the second zone that is far from the electrode assembly to lift up, less likely to interfere with other components, and less likely to cause the finishing adhesive to detach.

[0021] As an optional technical solution in this application embodiment, the adhesive layer includes a first adhesive segment and a second adhesive segment. Along the winding direction of the electrode assembly, the first adhesive segment is connected to one end of the second adhesive segment. The adhesiveness of the first adhesive segment is less than that of the second adhesive segment. The first region and the second region are connected through the first adhesive segment.

[0022] In the above technical solution, by making the viscosity of the first adhesive segment less than that of the second adhesive segment, the first region and the second region are connected through the first adhesive segment. When the electrode assembly expands, the first region can quickly separate from the second region, allowing the electrode assembly to expand.

[0023] As an optional technical solution in this application embodiment, the first region is located outside the second region, and the second region is connected to the electrode assembly through the adhesive layer.

[0024] In the above technical solution, by connecting the second zone to the electrode assembly through the adhesive layer, it is beneficial to reduce the risk of the second zone lifting and the risk of the finishing adhesive coming off.

[0025] As an optional technical solution in this application embodiment, the adhesive layer includes a first adhesive segment, a second adhesive segment, and a third adhesive segment. Along the winding direction of the electrode assembly, the first adhesive segment and the third adhesive segment are respectively connected to both ends of the second adhesive segment. The adhesiveness of the first adhesive segment and the adhesiveness of the third adhesive segment are both less than the adhesiveness of the second adhesive segment. The first region and the second region are connected through the first adhesive segment, and the second region and the electrode assembly are connected through the third adhesive segment.

[0026] In the above technical solution, by making the adhesion of the first adhesive segment less than that of the second adhesive segment, the first region can quickly separate from the second region when the electrode assembly expands, allowing the electrode assembly to expand. The first adhesive segment and the third adhesive segment are respectively connected to the two ends of the second adhesive segment. The adhesion of both the first adhesive segment and the third adhesive segment is less than that of the second adhesive segment, which helps to reduce the risk of incorrect assembly.

[0027] As an optional technical solution in this application embodiment, the peel strength of the first region and the second region is less than or equal to 1N / mm.

[0028] In the above technical solution, by making the peel strength of the first region and the second region less than or equal to 1N / mm, when the electrode assembly expands, the first region can separate from the second region more quickly, allowing the electrode assembly to expand.

[0029] As an optional technical solution in this application embodiment, the peel strength of the first region and the second region is less than or equal to 0.15 N / mm.

[0030] In the above technical solution, by making the peel strength of the first region and the second region less than or equal to 0.15 N / mm, when the electrode assembly expands, the first region can separate from the second region more quickly, allowing the electrode assembly to expand.

[0031] As an optional technical solution in this application embodiment, the battery cell is a cylindrical battery cell.

[0032] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0033] Thirdly, embodiments of this application also provide an electrical device, which includes the aforementioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0036] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0037] Figure 3 Exploded views of a single battery cell provided in some embodiments of this application;

[0038] Figure 4 This is a schematic diagram of the internal structure of a battery cell provided in some embodiments of this application;

[0039] Figure 5 for Figure 4 A magnified view of position A in the middle;

[0040] Figure 6 A schematic diagram of the internal structure of a battery cell (with a flat electrode assembly) provided in some embodiments of this application;

[0041] Figure 7 for Figure 6 Enlarged view of position F in the middle;

[0042] Figure 8 This is a schematic diagram of the internal structure of a battery cell provided in other embodiments of this application;

[0043] Figure 9 for Figure 8 A magnified view of position B in the middle;

[0044] Figure 10 This application provides schematic diagrams of the internal structure of a battery cell in some of its embodiments.

[0045] Figure 11 for Figure 10 A magnified view of position C in the middle;

[0046] Figure 12 This is a schematic diagram of the internal structure of a battery cell provided in some embodiments of this application;

[0047] Figure 13 for Figure 12 A magnified view of position D in the middle;

[0048] Figure 14 This application also provides schematic diagrams of the internal structure of a battery cell in some embodiments;

[0049] Figure 15 for Figure 14 A magnified view of position E in the middle.

[0050] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Battery cell; 21-Outer shell; 211-Shell; 212-End cap; 22-Electrode assembly; 221-Main body; 2211-First electrode; 22111-First section; 22112-Second section; 22113-Wound end of the first electrode; 2212-Second electrode; 22121-Wound end of the second electrode; 2213-Separator; 222-Taper; 2221-First tab; 2222-Second tab; 2 3-Electrode terminal; 24-Current collector; 241-First current collector; 242-Second current collector; 25-Finishing adhesive; 251-First end; 252-Second end; 253-Notch area; 254-Overlapping area; 255-Substrate; 2551-Main body area; 2552-First area; 2553-Second area; 256-Adhesive layer; 2561-First bonding section; 2562-Second bonding section; 2563-Third bonding section; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0053] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0056] In the embodiments of this application, the same reference numerals denote 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 this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0057] In this application, "multiple" means two or more (including two).

[0058] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0059] 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-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0060] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0061] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0062] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0063] As an example, the positive electrode current collector can be a foil or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0064] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0065] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0066] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0067] As an example, the negative electrode current collector can be a foil, a foamed metal, or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, or titanium, etc. The foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0068] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0069] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0070] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0071] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0072] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0073] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0074] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0075] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0076] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0077] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0078] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0079] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0080] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0081] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0082] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0083] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0084] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0085] In some implementations, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0086] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, or a composite metal (such as a copper-aluminum composite housing).

[0087] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0088] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0089] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0090] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0091] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0092] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cell assemblies housed within the housing.

[0093] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0094] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0095] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0096] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0097] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0098] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0099] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0100] The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery reliability must also be considered. However, current battery reliability is relatively poor.

[0101] During the manufacturing process of a battery cell, some particulate matter may be present in the casing (the particulate matter may be slag produced by welding, abrasive debris produced by equipment, or active material itself falling off). These particulate matter can easily penetrate the electrode assembly, causing the positive and negative electrode plates of the electrode assembly to short-circuit through the particulate matter, resulting in a short circuit and poor battery reliability.

[0102] Therefore, this application provides a battery cell, which includes an electrode assembly and a finishing adhesive. The electrode assembly includes a first electrode, a separator, and a second electrode. The first and second electrodes have opposite polarities and are wound together. The first electrode, separator, and second electrode are connected first and second segments, which are sequentially arranged along the winding direction of the electrode assembly. The second segment is the portion of the first electrode that extends beyond the winding end of the second electrode. The connection point between the first and second segments is located outside the winding end of the second electrode. The finishing adhesive is disposed on the outer periphery of the electrode assembly and has a first end and a second end in its circumferential direction. Both the first and second ends are located outside the second segment.

[0103] By applying the finishing adhesive to the outer periphery of the electrode assembly, not only can the winding end of the electrode assembly be fixed, maintaining its shape and structure, but it can also, to some extent, prevent particulate matter from piercing the separator, the first electrode, and the second electrode, reducing the risk of short circuits. By positioning the first and second ends outside the second segment, when particulate matter pierces the electrode assembly from the area between the first and second ends, it must penetrate at least four layers of separator, one layer of the first segment, and one layer of the second segment before a short circuit occurs, thus improving the reliability of the individual battery cells.

[0104] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0105] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0106] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0107] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0108] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0109] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and battery cells 20, the housing 10 being used to house the battery cells 20.

[0110] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which are interlocked. The first housing body 11 and the second housing body 12 can have various shapes, such as cuboids or cylinders. The first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can also be a hollow structure open on one side. The open side of the second housing body 12 interlocks with the open side of the first housing body 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can be a plate-like structure, with the second housing body 12 interlocked with the open side of the first housing body 11, thus forming a housing 10 with an accommodating chamber.

[0111] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0112] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0113] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , Figure 3 An exploded view of a battery cell 20 provided in some embodiments of this application. Figure 4This is a schematic diagram of the internal structure of a battery cell 20 provided in some embodiments of this application. Figure 5 for Figure 4 A magnified view of position A in the middle. Figure 6 This is a schematic diagram of the internal structure of a battery cell (with a flat electrode assembly) provided in some embodiments of this application. Figure 7 for Figure 6 Enlarged view of position F. This application provides a battery cell 20, which includes an electrode assembly 22 and a finishing adhesive 25. The electrode assembly 22 includes a first electrode 2211, a separator 2213, and a second electrode 2212. The first electrode 2211 and the second electrode 2212 have opposite polarities and are wound together. The first electrode 2211, the separator 2213, and the second electrode 2212 are connected segments 22111 and 22112. Along the winding direction of the electrode assembly 22, the first segment 22111 and the second segment 22112 are sequentially arranged. The second segment 22112 is the portion of the first electrode 2211 that extends beyond the winding finishing end 22121 of the second electrode. The connection point between the first segment 22111 and the second segment 22112 is located outside the winding finishing end 22121 of the second electrode. The finishing adhesive 25 is disposed on the outer periphery of the electrode assembly 22. The finishing adhesive 25 has a first end 251 and a second end 252 in its circumferential direction. Both the first end 251 and the second end 252 are located outside the second segment 22112.

[0114] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0115] The housing 21 includes a housing 211 and an end cap 212. The housing 211 has a receiving space with an opening at one end for accommodating the electrode assembly 22. The end cap 212 is connected to the housing 211 and closes the opening.

[0116] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 212 is less prone to deformation under pressure and impact, enabling battery cell 20 to have higher structural strength and improved reliability. The material of end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0117] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0118] In some embodiments, the housing 211 may have an opening at only one end, with one end cap 212 correspondingly provided. In other embodiments, the housing 211 may have openings at both ends, with two end caps 212 correspondingly provided, the two end caps 212 respectively closing the two opposite openings of the housing 211. Figure 3 and Figure 4 In the embodiment shown, the housing 211 has an opening at only one end, and an end cap 212 is provided accordingly.

[0119] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator 2213 is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 221 of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute a tab 222. The positive and negative tabs may be located together at one end of the main body 221 or separately at both ends of the main body 221. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte.

[0120] The battery cell 20 includes an electrode terminal 23, which is disposed on the housing 21. The electrode terminal 23 is used to electrically connect with the tab 222 of the electrode assembly 22 to input or output electrical energy of the battery cell 20.

[0121] Electrode terminal 23 and tab 222 can be directly connected, for example, by welding electrode terminal 23 to tab 222. Electrode terminal 23 and tab 222 can also be indirectly connected, for example, by connecting electrode terminal 23 and tab 222 indirectly through current collector 24. Current collector 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In some embodiments, there is one electrode terminal 23, one tab 222 of electrode assembly 22 (one of the positive tab and the negative tab) can be electrically connected to electrode terminal 23, and the other tab 222 of electrode assembly 22 (the other of the positive tab and the negative tab) can be electrically connected to housing 21.

[0122] As an example, such as Figure 3 and Figure 4 As shown, the housing 211 has an opening at only one end, and there is one end cap 212 covering the opening of the housing 211. Electrode terminals 23 are provided on the walls of the housing 211 opposite to the end cap 212. The electrode assembly 22 has tabs 222 at both ends. The tabs 222 at both ends of the electrode assembly 22 are a first tab 2221 and a second tab 2222, respectively. One of the first tab 2221 and the second tab 2222 is a positive tab, and the other is a negative tab. The electrode terminal 23 is electrically connected to the first tab 2221 through a first current collector 241, and the end cap 212 is electrically connected to the second tab 2222 through a second current collector 242.

[0123] Please refer to Figure 4 and Figure 5 ,exist Figure 4 and Figure 5 In the diagram, the first electrode 2211, the second electrode 2212, and the spacer 2213 are indicated by dashed lines. It should be noted that the dashed lines are only for the purpose of distinguishing the first electrode 2211, the second electrode 2212, and the spacer 2213, and do not indicate any other meaning.

[0124] One of the first electrode 2211 and the second electrode 2212 is the positive electrode as described above, and the other of the first electrode 2211 and the second electrode 2212 is the negative electrode as described above. For example, when the first electrode 2211 is the positive electrode, the second electrode 2212 is the negative electrode. Or, for example, when the first electrode 2211 is the negative electrode, the second electrode 2212 is the positive electrode.

[0125] The first electrode 2211, the separator 2213, and the second electrode 2212 are wound together to form an electrode assembly 22, that is, the electrode assembly 22 is a wound electrode assembly.

[0126] Please refer to Figure 4 and Figure 5In the embodiment shown in the figure, the battery cell 20 is a cylindrical battery cell, and the electrode assembly 22 is cylindrical. Please refer to... Figure 6 and Figure 7 In the embodiment shown in the figure, the battery cell 20 is a square-shell battery cell, and the electrode assembly 22 is flat.

[0127] Please refer to Figure 4 and Figure 5 The winding direction of electrode assembly 22 is the X direction shown in the figure.

[0128] The first electrode 2211 includes a first segment 22111 and a second segment 22112. The second segment 22112 is the portion of the first electrode 2211 that extends beyond the winding end 22121 of the second electrode along the winding direction of the electrode assembly 22. The end of the second segment 22112 away from the first segment 22111 is the winding end 22113 of the first electrode. The end of the second segment 22112 connected to the first segment 22111 is located outside the winding end 22121 of the second electrode. The end of the first segment 22111 away from the second segment 22112 is the winding start end of the first electrode 2211.

[0129] The winding end 22113 of the first electrode is the winding end of the first electrode 2211. Along the winding direction of the electrode assembly 22, the winding end 22113 of the first electrode is located at the end of the first electrode 2211, and is usually close to the outer layer of the electrode assembly 22. Correspondingly, the winding start end of the first electrode 2211, as the beginning of winding the first electrode 2211, is usually located inside the electrode assembly 22.

[0130] The winding end 22121 of the second electrode is the winding end of the second electrode 2212. Along the winding direction of the electrode assembly 22, the winding end 22121 of the second electrode is located at the end of the second electrode 2212, and is usually close to the outer layer of the electrode assembly 22. Correspondingly, the winding start end of the second electrode 2212, as the beginning of winding the second electrode 2212, is usually located inside the electrode assembly 22.

[0131] The finishing tape 25 is a tape used to fix the winding end portion of the electrode assembly 22. "The finishing tape 25 is disposed on the outer periphery of the electrode assembly 22" can mean that the finishing tape 25 partially surrounds the electrode assembly 22, in which case there is a notch area 253 between the two ends of the finishing tape 25; or the finishing tape 25 can completely surround the electrode assembly 22, in which case the finishing tape 25 can be annular, or a part of the finishing tape 25 can be disposed on the outside of the other part of the finishing tape 25.

[0132] The first end 251 and the second end 252 are the two ends of the finishing adhesive 25 in its circumferential direction, and both the first end 251 and the second end 252 are located on the outer side of the second segment 22112. Along the radial direction of the electrode assembly 22, the projections of the first end 251 and the second end 252 are both located on the second segment 22112.

[0133] By placing the finishing adhesive 25 on the outer periphery of the electrode assembly 22, not only can the winding and finishing portion of the electrode assembly 22 be fixed, maintaining the shape and structure of the electrode assembly 22, but it can also, to a certain extent, prevent particulate matter from piercing the separator 2213, the first electrode 2211, and the second electrode 2212, reducing the risk of short circuit. By placing the first end 251 and the second end 252 on the outside of the second segment 22112, when particulate matter pierces the electrode assembly 22 from the area between the first end 251 and the second end 252, the particulate matter needs to pierce at least four layers of separator 2213, one layer of first segment 22111, and one layer of second segment 22112 before a short circuit can occur, which helps to improve the reliability of the battery cell 20.

[0134] Please refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, a first end 251 and a second end 252 are spaced apart along the winding direction of the electrode assembly 22, and a gap region 253 is formed between the first end 251 and the second end 252.

[0135] The first end 251 and the second end 252 are spaced apart along the winding direction of the electrode assembly 22, and a gap region 253 is formed between the first end 251 and the second end 252.

[0136] The notch area 253 is the area of ​​the electrode assembly 22 not covered by the finishing adhesive 25. The electrode assembly 22 can be observed from the notch area 253, which is located on the outside of the second segment 22112.

[0137] By setting the first end 251 and the second end 252 at intervals along the winding direction of the electrode assembly 22, a gap area 253 is formed between the first end 251 and the second end 252. In this way, the finishing adhesive 25 will not have overlapping areas and will not form steps. When the electrode assembly 22 expands, the electrode assembly 22 is less likely to generate stress concentration, which is beneficial to improving the reliability of the battery cell 20.

[0138] Please refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, along the winding direction of the electrode assembly 22, the size of the notch region 253 is L1, and the length of the second segment 22112 is L2, satisfying: L1 / L2≤0.8.

[0139] L1 is the dimension of the notch region 253 along the winding direction of the electrode assembly 22, that is, the distance between the first end 251 and the second end 252 along the winding direction of the electrode assembly 22.

[0140] L2 represents the length of the second segment 22112 along the winding direction of the electrode assembly 22.

[0141] L1 / L2 represents the ratio of the dimension of the notch region 253 along the winding direction of the electrode assembly 22 to the length of the second segment 22112 along the winding direction of the electrode assembly 22.

[0142] L1 / L2 can be taken as: 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, etc.

[0143] When L1 / L2≤0.8, the size of the notch area 253 along the winding method of the electrode assembly 22 is small, which helps to reduce the risk of particles penetrating the electrode assembly 22 from the notch area 253 and helps to improve the protective effect of the finishing adhesive 25 on the electrode assembly 22.

[0144] Please refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the length of the second segment 22112 along the winding direction of the electrode assembly 22 is L2. The distance between the notch region 253 and the winding end 22113 of the first electrode sheet along the winding direction of the electrode assembly 22 is L3, satisfying: 0.1≤L3 / L2≤0.8.

[0145] L3 represents the distance between the notch area 253 and the winding end 22113 of the first electrode along the winding direction of the electrode assembly 22. When the first end 251 is closer to the winding end 22113 of the first electrode along the winding direction of the electrode assembly 22 than the second end 252, the distance between the first end 251 and the winding end 22113 of the first electrode along the winding direction of the electrode assembly 22 can also be used as L3. For ease of measurement, the distance from the first end 251 to the position of the finishing adhesive 25 corresponding to the winding end 22113 of the first electrode can be measured as L3.

[0146] L3 / L2 represents the ratio of the distance between the notch region 253 and the winding end 22113 of the first electrode sheet along the winding direction of the electrode assembly 22, and the length of the second segment 22112 along the winding direction of the electrode assembly 22.

[0147] L3 / L2 can be set to: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0148] When 0.1≤L3 / L2≤0.8, the distance between the notch region 253 and the winding end 22113 of the first electrode sheet along the winding direction of the electrode assembly 22 is moderate, so that the notch region 253 can be stably maintained on the outside of the second section 22112. In this way, particles need to pierce at least four layers of separators 2213, one layer of the first section 22111, and one layer of the second section 22112 to cause a short circuit, which is beneficial to improving the reliability of the battery cell 20.

[0149] Please refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the length of the second segment 22112 along the winding direction of the electrode assembly 22 is L2. The distance between the notch region 253 and the winding end 22121 of the second electrode sheet along the winding direction of the electrode assembly 22 is L4, satisfying: 0.1≤L4 / L2≤0.8.

[0150] L4 represents the distance between the notch area 253 and the winding end 22121 of the second electrode along the winding direction of the electrode assembly 22. When the second end 252 is closer to the winding end 22121 of the second electrode along the winding direction of the electrode assembly 22 than the first end 251, the distance between the second end 252 and the winding end 22121 of the second electrode along the winding direction of the electrode assembly 22 can also be used as L4. For ease of measurement, the distance from the second end 252 to the position of the finishing adhesive 25 corresponding to the winding end 22121 of the second electrode can be measured as L4.

[0151] L4 / L2 represents the ratio of the distance between the notch region 253 and the winding end 22121 of the second electrode along the winding direction of the electrode assembly 22, and the length of the second segment 22112 along the winding direction of the electrode assembly 22.

[0152] L4 / L2 can be set to: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0153] When 0.1≤L4 / L2≤0.8, the distance between the notch region 253 and the winding end 22121 of the second electrode is moderate along the winding direction of the electrode assembly 22, so that the notch region 253 can be stably maintained on the outside of the second section 22112. In this way, particles need to pierce at least four layers of separators 2213, one layer of the first section 22111, and one layer of the second section 22112 before a short circuit can occur, which is beneficial to improving the reliability of the battery cell 20.

[0154] Please refer to Figure 8 and Figure 9 , Figure 8 This is a schematic diagram of the internal structure of a battery cell 20 provided for other embodiments of this application. Figure 9 for Figure 8 Enlarged view of position B. In some embodiments, the finishing adhesive 25 has an overlapping area 254 located outside the second segment 22112.

[0155] A portion of the finishing adhesive 25 is disposed on the outside of another portion of the finishing adhesive 25, thereby forming an overlapping area 254, which is disposed on the outside of the second segment 22112. Along the radial direction of the electrode assembly 22, the projection of the overlapping area 254 is located on the second segment 22112.

[0156] By having an overlapping area 254 in the finishing adhesive 25, and placing the overlapping area 254 outside the second segment 22112, the finishing adhesive 25 can provide protection for the entire circumference of the electrode assembly 22, resulting in good protection. Furthermore, for particulate matter to penetrate the electrode assembly 22 through the overlapping area 254 and cause a short circuit, the particulate matter would need to penetrate at least two layers of finishing adhesive 25, four layers of separator 2213, one layer of the first segment 22111, and one layer of the second segment 22112. This reduces the risk of a short circuit and improves the reliability of the battery cell 20.

[0157] Please refer to Figure 8 and Figure 9 In some embodiments, the finishing adhesive 25 includes a substrate 255 and an adhesive layer 256, with the adhesive layer 256 connecting the electrode assembly 22 and the substrate 255. The substrate 255 includes a main region 2551 covered by the adhesive layer 256 and a first region 2552 not covered by the adhesive layer 256. Along the winding direction of the electrode assembly 22, the first region 2552 is connected to one end of the main region 2551, the end of the main region 2551 away from the first region 2552 is the first end 251, and the end of the first region 2552 away from the main region 2551 is the second end 252. The first region 2552 and a portion of the main region 2551 are stacked to form an overlapping region 254, with the portion of the main region 2551 located in the overlapping region 254 inside the first region 2552.

[0158] Substrate 255 is the "skeleton" or main material of finishing adhesive 25. Substrate 255 is mainly responsible for providing mechanical strength, thermal stability, chemical stability and electrical insulation. Substrate 255 can be a polymer film material such as polyimide (PI), polyethylene terephthalate (PET), polypropylene (PP) and polyethylene naphthalate (PEN).

[0159] Adhesive layer 256 is an adhesive coated on the surface of substrate 255. Adhesive layer 256 is mainly responsible for providing reliable and durable adhesion. Adhesive layer 256 may have properties such as resistance to electrolyte, high temperature resistance, and insulation.

[0160] The main body region 2551 is the area on the substrate 255 covered by the adhesive layer 256, and is the main part of the finishing adhesive 25. The first region 2552 is not covered by the adhesive layer 256, and all parts of the substrate 255 except for the main body region 2551 are the first region 2552. The first region 2552 is connected to one end of the main body region 2551 along the winding direction of the electrode assembly 22. The end of the main body region 2551 away from the first region 2552 is the first end 251, and the end of the first region 2552 away from the main body region 2551 is the second end 252.

[0161] The first region 2552 and a portion of the main region 2551 are stacked to form an overlapping region 254. The portion of the main region 2551 located in the overlapping region 254 is also the portion where the main region 2551 and the first region 2552 are stacked. The portion of the main region 2551 located in the overlapping region 254 is inside the first region 2552, and the first region 2552 is outside the portion of the main region 2551 located in the overlapping region 254. In other words, the portion of the first region 2552 located in the overlapping region 254 is not bonded to the main region 2551.

[0162] The first region 2552 and a portion of the main region 2551 are stacked to form an overlapping region 254. The portion of the main region 2551 located in the overlapping region 254 is bonded to the electrode assembly 22, while the portion of the first region 2552 located in the overlapping region 254 is not bonded to the main region 2551. In this way, when the electrode assembly 22 expands, the first region 2552 can quickly separate from the main region 2551, allowing the electrode assembly 22 to expand.

[0163] Please refer to Figure 10 and Figure 11 , Figure 10 This is a schematic diagram of the internal structure of a battery cell 20 provided in some embodiments of this application. Figure 11 for Figure 10 Enlarged view of position C. In some embodiments, the finishing adhesive 25 includes a substrate 255 and an adhesive layer 256, with the adhesive layer 256 connecting the electrode assembly 22 and the substrate 255. The substrate 255 includes a main region 2551 covered by the adhesive layer 256, a first region 2552 not covered by the adhesive layer 256, and a second region 2553 not covered by the adhesive layer 256. Along the winding direction of the electrode assembly 22, the first region 2552 and the second region 2553 are respectively connected to both ends of the main region 2551. The end of the first region 2552 away from the main region 2551 is the second end 252, and the end of the second region 2553 away from the main region 2551 is the first end 251. The first region 2552 and the second region 2553 are stacked to form an overlapping region 254.

[0164] The main body region 2551 is the area on the substrate 255 covered by the adhesive layer 256, and is the main part of the finishing adhesive 25. The first region 2552 and the second region 2553 are not covered by the adhesive layer 256, and are respectively connected to both ends of the main body region 2551 along the winding direction of the electrode assembly 22. The end of the first region 2552 furthest from the main body region 2551 is the second end 252, and the end of the second region 2553 furthest from the main body region 2551 is the first end 251.

[0165] The first region 2552 and the second region 2553 are stacked to form an overlapping region 254. At this time, the first region 2552 and the second region 2553 are not bonded to each other, nor are the first region 2552 and the second region 2553 bonded to the electrode assembly 22.

[0166] The first zone 2552 and the second zone 2553 are respectively connected to the two ends of the main body zone 2551. Neither the first end 251 nor the second end 252 is covered by the adhesive layer 256, which helps to reduce the risk of incorrect assembly.

[0167] Please refer to Figure 12 and Figure 13 , Figure 12 This is a schematic diagram of the internal structure of a battery cell 20 provided in some embodiments of this application. Figure 13 for Figure 12 Enlarged view of position D. In some embodiments, the finishing adhesive 25 includes a substrate 255 and an adhesive layer 256, with the adhesive layer 256 connecting the electrode assembly 22 and the substrate 255. The substrate 255 includes a first region 2552 and a second region 2553 located within an overlap region 254, with the first region 2552 and the second region 2553 overlapping. One end of the first region 2552 is the second end 252, and one end of the second region 2553 is the first end 251. The first region 2552 and the second region 2553 are connected by the adhesive layer 256.

[0168] Both the first region 2552 and the second region 2553 are portions of the substrate 255 located within the overlapping region 254. One end of the first region 2552 is the second end 252, and one end of the second region 2553 is the first end 251. An adhesive layer 256 is provided on the first region 2552, and the first region 2552 and the second region 2553 are bonded together. At this time, the second region 2553 can be bonded to the electrode assembly 22, or it can be left unbonded to the electrode assembly 22.

[0169] The first zone 2552 and the second zone 2553 are connected by the adhesive layer 256, so that the one of the first zone 2552 and the second zone 2553 that is far from the electrode assembly 22 is not easy to lift up, not easy to interfere with other components, and not easy to cause the finishing adhesive 25 to delaminate.

[0170] Please refer to Figure 12 and Figure 13 In some embodiments, the adhesive layer 256 includes a first adhesive segment 2561 and a second adhesive segment 2562. Along the winding direction of the electrode assembly 22, the first adhesive segment 2561 is connected to one end of the second adhesive segment 2562, and the adhesiveness of the first adhesive segment 2561 is less than that of the second adhesive segment 2562. The first region 2552 and the second region 2553 are connected through the first adhesive segment 2561.

[0171] The substrate 255 includes a main body area 2551, a first area 2552, and a second area 2553, with the main body area 2551 connected to the first area 2552 and the second area 2553.

[0172] The first adhesive segment 2561 is the part of the adhesive layer 256 that connects the first region 2552 and the second region 2553. The second adhesive segment 2562 is the part of the adhesive layer 256 that connects the main body region 2551 and the electrode assembly 22. The first adhesive segment 2561 is connected to one end of the second adhesive segment 2562 along the winding direction of the electrode assembly 22.

[0173] The adhesiveness of the first adhesive segment 2561 is less than that of the second adhesive segment 2562, which can be represented by the fact that the peel strength of the first region 2552 and the second region 2553 is less than the peel strength of the main body region 2551 and the electrode assembly 22.

[0174] The test methods for peel strength of Zone 1 2552 and Zone 2553 are as follows:

[0175] Disassemble the battery cell 20 and remove the electrode assembly 22. Disassemble the electrode assembly 22, leaving the connected first region 2552 and second region 2553. Cut the sample into 25mm*25mm pieces. Apply double-sided tape to the surface of the second region 2553 facing away from the first region 2552 and attach it to the steel plate. Peel off 5mm from the end of the first region 2552, fix the steel plate parallel to the tensile testing machine, and connect the peeled first region 2552 to the upper clamp of the tensile testing machine. Click the start button, and the upper clamp moves upward at a speed of 100mm / min, with a maximum movement distance of 20mm. The tensile testing machine can obtain the peel force and convert the peel force into the peel strength of the first region 2552 and the second region 2553.

[0176] The test method for the peel strength of the main body region 2551 and the electrode assembly 22 is as follows:

[0177] Disassemble the battery cell 20 and remove the electrode assembly 22. Disassemble the electrode assembly 22, leaving the connected main body area 2551 and separator 2213. Cut the sample into 25mm*25mm pieces. Apply double-sided tape to the surface of the main body area 2551 facing away from the separator 2213 and attach it to the steel plate. Peel off 5mm from the end of the separator 2213, fix the steel plate parallel to the tensile testing machine, and connect the peeled separator 2213 to the upper clamp of the tensile testing machine. Click the start button, and the upper clamp moves upward at a speed of 100mm / min, with a maximum movement distance of 20mm. The tensile testing machine can obtain the peel force and convert the peel force into the peel strength between the main body area 2551 and the electrode assembly 22.

[0178] In some embodiments, the thickness of the first adhesive segment 2561 is less than the thickness of the second adhesive segment 2562, such that the adhesiveness of the first adhesive segment 2561 is less than the adhesiveness of the second adhesive segment 2562.

[0179] By making the adhesiveness of the first adhesive segment 2561 less than that of the second adhesive segment 2562, the first region 2552 and the second region 2553 are connected through the first adhesive segment 2561. When the electrode assembly 22 expands, the first region 2552 can quickly separate from the second region 2553, allowing the electrode assembly 22 to expand.

[0180] Please refer to Figure 14 and Figure 15 , Figure 14 The present application also provides schematic diagrams of the internal structure of the battery cell 20 in some embodiments. Figure 15 for Figure 14 Enlarged view of position E in the middle. In some embodiments, the first region 2552 is located outside the second region 2553, and the second region 2553 is connected to the electrode assembly 22 through the adhesive layer 256.

[0181] The second region 2553 is connected to the electrode assembly 22 through the adhesive layer 256, that is, the second region 2553 is bonded to the electrode assembly 22.

[0182] By connecting the second zone 2553 to the electrode assembly 22 through the adhesive layer 256, it is beneficial to reduce the risk of the second zone 2553 lifting and the risk of the finishing adhesive 25 coming off.

[0183] Please refer to Figure 14 and Figure 15In some embodiments, the adhesive layer 256 includes a first adhesive segment 2561, a second adhesive segment 2562, and a third adhesive segment 2563. Along the winding direction of the electrode assembly 22, the first adhesive segment 2561 and the third adhesive segment 2563 are respectively connected to both ends of the second adhesive segment 2562. The adhesiveness of both the first adhesive segment 2561 and the third adhesive segment 2563 is less than that of the second adhesive segment 2562. The first region 2552 and the second region 2553 are connected through the first adhesive segment 2561, and the second region 2553 and the electrode assembly 22 are connected through the third adhesive segment 2563.

[0184] The substrate 255 includes a main body region 2551, a first region 2552, and a second region 2553, with the main body region 2551 connecting the first region 2552 and the second region 2553. A first adhesive segment 2561 is the portion of the adhesive layer 256 connecting the first region 2552 and the second region 2553; a second adhesive segment 2562 is the portion of the adhesive layer 256 connecting the main body region 2551 and the electrode assembly 22; and a third adhesive segment 2563 is the portion of the adhesive layer 256 connecting the second region 2553 and the electrode assembly 22. The first adhesive segment 2561 and the third adhesive segment 2563 are respectively connected to both ends of the second adhesive segment 2562.

[0185] The adhesiveness of the third adhesive segment 2563 is less than that of the second adhesive segment 2562, which can be represented by the fact that the peel strength of the second region 2553 and the electrode assembly 22 is less than that of the main body region 2551 and the electrode assembly 22.

[0186] The test method for the peel strength of the second zone 2553 and electrode assembly 22 is as follows:

[0187] Disassemble the battery cell 20 and remove the electrode assembly 22. Disassemble the electrode assembly 22, leaving the connected second region 2553 and separator 2213. Cut the sample into 25mm*25mm pieces. Apply double-sided tape to the surface of the second region 2553 facing away from the separator 2213 and attach it to the steel plate. Peel off 5mm from the end of the separator 2213, fix the steel plate parallel to the tensile testing machine, and connect the peeled separator 2213 to the upper clamp of the tensile testing machine. Click the start button, and the upper clamp moves upward at a speed of 100mm / min, with a maximum movement distance of 20mm. The tensile testing machine can obtain the peel force and convert the peel force into the peel strength between the second region 2553 and the electrode assembly 22.

[0188] In some embodiments, the thickness of the first adhesive segment 2561 and the thickness of the third adhesive segment 2563 are both less than the thickness of the second adhesive segment 2562, such that the adhesiveness of the first adhesive segment 2561 and the adhesiveness of the third adhesive segment 2563 are both less than the adhesiveness of the second adhesive segment 2562.

[0189] By making the adhesive strength of the first adhesive segment 2561 less than that of the second adhesive segment 2562, when the electrode assembly 22 expands, the first region 2552 can quickly separate from the second region 2553, allowing the electrode assembly 22 to expand. The first adhesive segment 2561 and the third adhesive segment 2563 are respectively connected to the two ends of the second adhesive segment 2562. The adhesive strength of both the first adhesive segment 2561 and the third adhesive segment 2563 is less than that of the second adhesive segment 2562, which helps to reduce the risk of incorrect assembly.

[0190] In some embodiments, the peel strength of the first region 2552 and the second region 2553 is less than or equal to 1 N / mm.

[0191] The peel strength of Zone 1 2552 and Zone 2553 can be: 1N / mm, 0.9N / mm, 0.8N / mm, 0.7N / mm, 0.6N / mm, 0.5N / mm, 0.4N / mm, 0.3N / mm, 0.2N / mm, 0.1N / mm, etc.

[0192] By making the peel strength of the first region 2552 and the second region 2553 less than or equal to 1 N / mm, when the electrode assembly 22 expands, the first region 2552 can separate from the second region 2553 more quickly, allowing the electrode assembly 22 to expand.

[0193] Optionally, the peel strength of the first zone 2552 and the second zone 2553 is less than or equal to 0.15 N / mm.

[0194] The peel strength of Zone 1 2552 and Zone 2553 can be: 0.15N / mm, 0.14N / mm, 0.13N / mm, 0.12N / mm, 0.11N / mm, 0.1N / mm, 0.09N / mm, 0.08N / mm, 0.07N / mm, 0.06N / mm, etc.

[0195] By making the peel strength of the first region 2552 and the second region 2553 less than or equal to 0.15 N / mm, the first region 2552 can separate from the second region 2553 more quickly when the electrode assembly 22 expands, allowing the electrode assembly 22 to expand.

[0196] In some embodiments, the battery cell 20 is a cylindrical battery cell.

[0197] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0198] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0199] According to some embodiments of this application, please refer to Figures 3-15 .

[0200] This application provides a battery cell 20, which includes an electrode assembly 22 and a finishing adhesive 25. The electrode assembly 22 includes a first electrode 2211, a separator 2213, and a second electrode 2212. The first electrode 2211 and the second electrode 2212 have opposite polarities and are wound together. The first electrode 2211, the separator 2213, and the second electrode 2212 are connected. The first electrode 2211 includes a first segment 22111 and a second segment 22112 connected together. Along the winding direction of the electrode assembly 22, the first segment 22111 and the second segment 22112 are arranged sequentially. The second segment 22112 is the portion of the first electrode 2211 that extends beyond the winding finishing end 22121 of the second electrode. The connection point between the first segment 22111 and the second segment 22112 is located outside the winding finishing end 22121 of the second electrode. The finishing adhesive 25 is disposed on the outer periphery of the electrode assembly 22. The finishing adhesive 25 has a first end 251 and a second end 252 in its circumferential direction, both of which are located outside the second segment 22112. By disposing of the finishing adhesive 25 on the outer periphery of the electrode assembly 22, not only can the winding end portion of the electrode assembly 22 be fixed, maintaining the shape and structure of the electrode assembly 22, but it can also, to a certain extent, prevent particulate matter from piercing the separator 2213, the first electrode 2211, and the second electrode 2212, reducing the risk of short circuit. By disposing of the first end 251 and the second end 252 outside the second segment 22112, when particulate matter pierces the electrode assembly 22 from the area between the first end 251 and the second end 252, the particulate matter needs to pierce at least four layers of separator 2213, one layer of first segment 22111, and one layer of second segment 22112 before a short circuit can occur, which is beneficial to improving the reliability of the battery cell 20.

[0201] In some embodiments, a first end 251 and a second end 252 are spaced apart along the winding direction of the electrode assembly 22, and a gap region 253 is formed between the first end 251 and the second end 252. By spaced the first end 251 and the second end 252 along the winding direction of the electrode assembly 22, and forming a gap region 253 between the first end 251 and the second end 252, there will be no overlapping area of ​​the finishing adhesive 25, and no step will be formed. When the electrode assembly 22 expands, the electrode assembly 22 is less prone to stress concentration, which helps to improve the reliability of the battery cell 20.

[0202] In other embodiments, the finishing adhesive 25 has an overlapping region 254 located outside the second segment 22112. The finishing adhesive 25 includes a substrate 255 and an adhesive layer 256, with the adhesive layer 256 connecting the electrode assembly 22 and the substrate 255. The substrate 255 includes a main region 2551 covered by the adhesive layer 256 and a first region 2552 not covered by the adhesive layer 256. Along the winding direction of the electrode assembly 22, the first region 2552 is connected to one end of the main region 2551, with the end of the main region 2551 away from the first region 2552 being the first end 251, and the end of the first region 2552 away from the main region 2551 being the second end 252. The first region 2552 and a portion of the main region 2551 are stacked to form the overlapping region 254, with the portion of the main region 2551 located in the overlapping region 254 inside the first region 2552. The first region 2552 and a portion of the main region 2551 are stacked to form an overlapping region 254. The portion of the main region 2551 located in the overlapping region 254 is bonded to the electrode assembly 22, while the portion of the first region 2552 located in the overlapping region 254 is not bonded to the main region 2551. In this way, when the electrode assembly 22 expands, the first region 2552 can quickly separate from the main region 2551, allowing the electrode assembly 22 to expand.

[0203] In other embodiments, the finishing adhesive 25 has an overlapping region 254 located outside the second segment 22112. The finishing adhesive 25 includes a substrate 255 and an adhesive layer 256, with the adhesive layer 256 connecting the electrode assembly 22 and the substrate 255. The substrate 255 includes a first region 2552 and a second region 2553 located within the overlapping region 254, with the first region 2552 and the second region 2553 overlapping each other. One end of the first region 2552 is the second end 252, and one end of the second region 2553 is the first end 251. The adhesive layer 256 includes a first adhesive segment 2561 and a second adhesive segment 2562. Along the winding direction of the electrode assembly 22, the first adhesive segment 2561 is connected to one end of the second adhesive segment 2562, and the adhesive strength of the first adhesive segment 2561 is less than that of the second adhesive segment 2562. The first region 2552 and the second region 2553 are connected through the first adhesive segment 2561. By making the adhesiveness of the first adhesive segment 2561 less than that of the second adhesive segment 2562, the first region 2552 and the second region 2553 are connected through the first adhesive segment 2561. When the electrode assembly 22 expands, the first region 2552 can quickly separate from the second region 2553, allowing the electrode assembly 22 to expand.

[0204] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: An electrode assembly includes a first electrode, an isolator, and a second electrode. The first electrode and the second electrode have opposite polarities. The first electrode, the isolator, and the second electrode are wound together. The first electrode includes a first segment and a second segment connected together. The first segment and the second segment are arranged sequentially along the winding direction of the electrode assembly. The second segment is the portion of the first electrode that extends beyond the winding end of the second electrode. The connection point between the first segment and the second segment is located outside the winding end of the second electrode. A finishing adhesive is disposed on the outer periphery of the electrode assembly. The finishing adhesive has a first end and a second end in its circumferential direction. The first end and the second end are both located outside the second segment and are both disposed corresponding to the second segment. Wherein, along the winding direction of the electrode assembly, the first end and the second end are spaced apart, and a gap area is formed between the first end and the second end; or the finishing adhesive has an overlapping area, and the overlapping area is located on the outside of the second segment.

2. The battery cell according to claim 1, characterized in that, Along the winding direction of the electrode assembly, the size of the notch area is L1, and the length of the second segment is L2, satisfying: L1 / L2≤0.

8.

3. The battery cell according to claim 1, characterized in that, Along the winding direction of the electrode assembly, the length of the second segment is L2; Along the winding direction of the electrode assembly, the distance between the notch region and the winding end of the first electrode sheet is L3, satisfying: 0.1≤L3 / L2≤0.8; and / or Along the winding direction of the electrode assembly, the distance between the notch area and the winding end of the second electrode is L4, satisfying: 0.1≤L4 / L2≤0.

8.

4. The battery cell according to claim 1, characterized in that, The finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a main area covered by the adhesive layer and a first area not covered by the adhesive layer. Along the winding direction of the electrode assembly, the first area is connected to one end of the main area. The end of the main area away from the first area is the first end, and the end of the first area away from the main area is the second end. The first area and a portion of the main area are stacked to form the overlapping area. The portion of the main area located in the overlapping area is located inside the first area.

5. The battery cell according to claim 1, characterized in that, The finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a main area covered by the adhesive layer, a first area not covered by the adhesive layer, and a second area not covered by the adhesive layer. Along the winding direction of the electrode assembly, the first area and the second area are respectively connected to both ends of the main area. The end of the first area away from the main area is the second end, and the end of the second area away from the main area is the first end. The first area and the second area are stacked and form the overlapping area.

6. The battery cell according to claim 1, characterized in that, The finishing adhesive includes a substrate and an adhesive layer. The adhesive layer connects the electrode assembly and the substrate. The substrate includes a first region and a second region located within the overlapping area. The first region and the second region are overlapped. One end of the first region is the second end, and one end of the second region is the first end. The first region and the second region are connected by the adhesive layer.

7. The battery cell according to claim 6, characterized in that, The adhesive layer includes a first adhesive segment and a second adhesive segment. Along the winding direction of the electrode assembly, the first adhesive segment is connected to one end of the second adhesive segment. The adhesive strength of the first adhesive segment is less than that of the second adhesive segment. The first region and the second region are connected through the first adhesive segment.

8. The battery cell according to claim 6, characterized in that, The first region is located outside the second region, and the second region is connected to the electrode assembly through the adhesive layer.

9. The battery cell according to claim 8, characterized in that, The adhesive layer includes a first adhesive section, a second adhesive section, and a third adhesive section. Along the winding direction of the electrode assembly, the first adhesive section and the third adhesive section are respectively connected to both ends of the second adhesive section. The adhesiveness of the first adhesive section and the adhesiveness of the third adhesive section are both less than the adhesiveness of the second adhesive section. The first region and the second region are connected through the first adhesive section, and the second region and the electrode assembly are connected through the third adhesive section.

10. The battery cell according to claim 6, characterized in that, The peel strength of the first region and the second region is less than or equal to 1 N / mm.

11. The battery cell according to claim 10, characterized in that, The peel strength of the first region and the second region is less than or equal to 0.15 N / mm.

12. The battery cell according to any one of claims 1-11, characterized in that, The battery cell is a cylindrical battery cell.

13. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-12.

14. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1-12, the battery cell being used to provide electrical energy to the electrical device.

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