Battery monomer, battery device and electric equipment

Abstract

The utility model relates to a battery monomer, a battery device and electric equipment, the battery monomer comprises a shell and an electrode assembly, and the shell is provided with an accommodating cavity; the electrode assembly is arranged in the accommodating cavity and comprises a first pole piece, a separator and a second pole piece, the polarities of the first pole piece and the second pole piece are opposite, the separator is used for separating the first pole piece and the second pole piece, the first pole piece comprises a pole piece main body and a pole lug led out from the pole piece main body, and the pole piece main body points to the direction of the pole lug; the parts, protruding out of the pole piece main body, of the separators located on the two sides of the first pole piece are mutually welded to form welding parts, and the pole piece main body and the welding parts are arranged at intervals in the direction from the pole piece main body to the pole lugs. According to the battery monomer provided by the invention, the edge sealing structure is formed by the welding part, so that at least part of the edge of the first pole piece can be wrapped, the edge lap joint of the first pole piece and the second pole piece is effectively inhibited, the occurrence of short circuit in the electrode assembly is reduced, and the reliability of the battery monomer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery production, in particular to a battery monomer, a battery device and an electric equipment. BACKGROUND

[0002] Battery monomers are widely used in electronic devices such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools, etc. The battery monomers can include cadmium-nickel batteries, hydrogen-nickel batteries, lithium-ion batteries and secondary alkaline zinc-manganese batteries, etc.

[0003] In the development of batteries, how to provide the reliability of the battery monomer is a technical problem to be solved in the battery technology. UTILITY MODEL CONTENT

[0004] The present application provides a battery monomer, a battery device and an electric equipment, which aims to improve the reliability of the battery monomer to some extent.

[0005] In a first aspect, the present application provides a battery monomer, which comprises a shell and an electrode assembly, the shell having a receiving cavity; the electrode assembly is arranged in the receiving cavity, and the electrode assembly comprises a first electrode sheet, a separator and a second electrode sheet, the polarities of the first electrode sheet and the second electrode sheet are opposite, the separator is used to separate the first electrode sheet and the second electrode sheet, the first electrode sheet comprises an electrode sheet main body and a tab led out from the electrode sheet main body, and along the direction of the electrode sheet main body pointing to the tab, the parts of the separators protruding from the electrode sheet main body on both sides of the first electrode sheet are mutually fused and form a fusion part; along the direction of the electrode sheet main body pointing to the tab, the electrode sheet main body and the fusion part are arranged at intervals.

[0006] The battery monomer provided by the present application is provided with two separators arranged on both sides of the first electrode sheet, and the parts of the two separators protruding from the first electrode sheet are mutually fused to form a fusion part. The fusion part constitutes a sealing edge structure, which can wrap at least part of the edge of the first electrode sheet, effectively inhibit the edge overlap of the first electrode sheet and the second electrode sheet, reduce the occurrence of internal short circuit of the electrode assembly, and improve the reliability of the battery monomer.

[0007] According to an embodiment of the present application, the fusion part is configured to be formed by laser heat fusion.

[0008] In these optional embodiments, since the laser does not directly contact the separators during processing, the problems such as belt breakage, wrinkling and stress concentration of the separators are improved, so that the separators have higher structural integrity and processing stability.

[0009] According to an embodiment of the present application, the fusion part is arranged at one end of the separator close to the tab.

[0010] In these optional embodiments, the welding portion is arranged at one end close to the tab, and the welding portion protects the first tab, reducing the probability of contact between the two tabs and the risk of short circuit.

[0011] According to one embodiment of the present application, the welding portion is also arranged at the other end of the separator away from the tab.

[0012] In these optional embodiments, both ends of the separator form welding portions to wrap the edges of both ends of the first tab, further reducing the probability of edge overlap between the first tab and the second tab and the possibility of thermal runaway caused by short circuit.

[0013] According to one embodiment of the present application, in the direction of the tab body pointing to the tab, the size of the welding portion is less than or equal to 2 mm.

[0014] In these optional embodiments, in the compact internal environment of the battery cell, the welding portion has a suitable size, reducing the space occupied by the welding portion and also reducing the amount of material used by the separator for welding, improving processing efficiency.

[0015] According to one embodiment of the present application, in the direction of the tab body pointing to the tab, the welding portion is arranged apart from the edge of the separator close to the welding portion.

[0016] In these optional embodiments, the welding portion is arranged apart from the edge of the separator, leaving a fault-tolerant space and improving production efficiency.

[0017] According to one embodiment of the present application, in the direction of the tab body pointing to the tab, the distance L1 between the welding portion and the edge of the separator close to the welding portion is less than or equal to 1 mm.

[0018] In these optional embodiments, the distance L1 between the welding portion and the edge of the separator is less than or equal to 1 mm, and the welding portion is a stable connection structure formed by the welding of the separator, which can effectively disperse the stress in the edge area, improve the excessive concentration of stress in the edge, and reduce the risk of fracture or breakage of the separator.

[0019] According to one embodiment of the present application, in the direction of the tab body pointing to the tab, the distance L2 between the welding portion and the tab body is less than or equal to 1 mm.

[0020] In these optional embodiments, the welding portion has a suitable distance from the tab body, reducing the redundancy of the separator and improving the space utilization rate inside the battery cell.

[0021] According to one embodiment of the present application, the first tab, the separator, and the second tab are wound to form a bending area and a flat area connected to the bending area; and the welding portion is arranged at least in the flat area.

[0022] In these optional embodiments, the welding portion can tightly fix the separators on both sides of the first tab, so that reliable mechanical support is formed between the two separators and the first tab, and the electrode assembly after winding has higher structural stability. In the same volume, more electrode materials can be arranged to withstand greater working current and higher energy density, thereby improving the overall performance and service life of the battery cell.

[0023] According to an embodiment of the present application, the welding portion is also arranged at the bending area.

[0024] According to an embodiment of the present application, the welding portion extends along the winding direction of the separator.

[0025] In these optional embodiments, the welding portion extending along the winding direction has consistency with the extension direction of the separator and the first tab, to form a linear continuous edge sealing structure. The first tab is more uniformly bound between the separators on both sides, providing continuous mechanical constraint for the winding structure, reducing local looseness or edge lifting, and also reducing the risk of interlayer slip.

[0026] According to an embodiment of the present application, the battery cell includes a plurality of welding portions, which are arranged at intervals along the winding direction of the separator.

[0027] In these optional embodiments, the channel between the two welding portions can be used as a channel for electrolyte penetration, so that the electrolyte can spread more quickly and uniformly throughout the battery cell, improving the stability of ion conduction.

[0028] In a second aspect, the present application provides a battery device, comprising the battery cell according to the foregoing.

[0029] In a third aspect, the present application provides a power consuming device, comprising the battery cell according to the foregoing or the battery device according to the foregoing, and the battery cell or the battery device is used for storing or providing electric energy.

[0030] The above description is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more obvious and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0031] The features, advantages, and technical effects of the exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0032] Figure 1 is a structural schematic diagram of a vehicle provided by an embodiment of the present application;

[0033] Figure 2 is an exploded view of a battery device provided by an embodiment of the present application;

[0034] Figure 3 is an exploded view of a battery cell provided by an embodiment of the application;

[0035] Figure 4 is a structural schematic view of an electrode assembly of a battery cell provided by an embodiment of the application;

[0036] Figure 5 is a partial structural schematic view of an electrode assembly of a battery cell in a flattened state provided by an embodiment of the application;

[0037] Figure 6 is a front view of an electrode assembly of a battery cell provided by an embodiment of the application;

[0038] Figure 7 is a front view of an electrode assembly of a battery cell provided by another embodiment of the application;

[0039] Figure 8 is a front view of an electrode assembly of a battery cell provided by yet another embodiment of the application;

[0040] Figure 9 is a structural schematic view of an electrode assembly of a battery cell in a flattened state provided by an embodiment of the application;

[0041] Figure 10 is Figure 9 is an enlarged schematic view at a;

[0042] Figure 11 is a cross-sectional structural schematic view of a winding structure of a battery cell provided by an embodiment of the application;

[0043] Figure 12 is a partial structural schematic view of an electrode assembly of a battery cell provided by an embodiment of the application;

[0044] Figure 13 is another angle partial structural schematic view of an electrode assembly of a battery cell provided by an embodiment of the application.

[0045] The accompanying drawings are not necessarily drawn to scale.

[0046] Explanation of Reference Signs:

[0047] 1000, vehicle; 100, battery device; 200, controller; 300, motor;

[0048] 1a, battery module; 1b, first case; 1c, second case; 10, battery cell;

[0049] 1, housing; 11, accommodating cavity; 2, electrode assembly; 21, first tab; 211, tab body; 212, tab lug; 22, second tab; 23, spacer; 24, fusion portion; W, bending area; P, flat area; x, first direction; y, second direction; m, winding direction. DETAILED DESCRIPTION

[0050] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0051] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, rather than to describe a particular order or primary and secondary relationship.

[0052] In the present application, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0053] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connect", "attach" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] In the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0055] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length, width, and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0056] The "multiple" appearing in the present application refers to two or more (including two).

[0057] At present, from the development of market situation, the application of the battery is more and more widely. The battery is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields.

[0058] The battery device generally refers to a single physical module including a plurality of battery monomers to provide higher voltage and capacity. The battery monomer can be the smallest unit constituting the battery device.

[0059] In the electrode assembly manufacturing process, the edge of the pole piece is prone to curling, which causes the edge of the first pole piece and the second pole piece to overlap, thereby causing internal short circuit of the battery monomer, reducing the reliability of the battery monomer. The above statements are only used to provide background technology information related to the present application, and do not necessarily constitute the prior art.

[0060] The battery monomer provided by the present application is provided with two isolation pieces arranged on both sides of the first pole piece, and the parts protruding from the first pole piece of the two isolation pieces are mutually fused to form a fusion part. The fusion part constitutes a sealing structure, which can wrap at least part of the edge of the first pole piece, effectively prevent the edge of the first pole piece and the second pole piece from overlapping, reduce the occurrence of internal short circuit of the electrode assembly, and improve the reliability of the battery monomer.

[0061] The battery monomer described in the embodiments of the present application is suitable for batteries and electric equipment using batteries. The battery monomer can be used in batteries, but not limited to, and can also be used in vehicles, aircraft, ships, electronic equipment, electric tools and other products, which can improve the reliability of these products.

[0062] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0063] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0064] See Figure 1 As shown, one embodiment of this application provides a vehicle 1000. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. In one embodiment of this application, the vehicle 1000 may include a motor 300, a controller 200, and a battery device 100. The controller 200 is used to control the battery device 100 to supply power to the motor 300. The motor 300 is connected to the wheels via a transmission mechanism, thereby driving the vehicle 1000. The battery device 100 can serve as the driving power source for the vehicle 1000, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle 1000. In one example, 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 supply power to the vehicle 1000. In one example, the battery device 100 can serve as the operating power source for the vehicle 1000's electrical system. For example, the battery device 100 can be used to meet the power needs of the vehicle 1000 during startup, navigation and operation.

[0065] Please refer to Figure 2 , Figure 2 An exploded view of a battery device 100 provided in some embodiments of this application.

[0066] In some embodiments, the battery device 100 may include one or more battery cell assemblies for providing voltage and capacity.

[0067] A battery cell assembly may include multiple battery cells ( Figure 2 (Not shown) Multiple battery cells are connected in series, parallel, or mixed connection through a busbar. Mixed connection refers to multiple battery cells being connected in both series and parallel.

[0068] The battery cell can be a secondary battery cell, which refers to a battery cell that can be used continuously by activating the active material through charging after discharging the battery cell.

[0069] As an example, the battery cell can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead storage battery cell, etc.

[0070] As an example, the battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, the prismatic battery cell including a square battery cell, a blade battery cell, a multi-prismatic battery cell, such as a hexagonal battery cell, etc.

[0071] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module 1a, which is formed by arranging and fixing a plurality of battery cells into one independent module. As an example, the battery module 1a can be formed by bundling a plurality of battery cells with a cable tie.

[0072] In some embodiments, the battery device 100 can be a battery pack, which includes a case and one or more battery cell assemblies accommodated in the case. As an example, the battery cell assembly can be a battery module 1a, which can be accommodated in the case by fixing the battery module 1a in the case. As an example, the battery cell assembly can also be accommodated in the case by directly fixing a plurality of battery cells in the case.

[0073] In some embodiments, the case for accommodating the battery cell can be of various structures.

[0074] In some embodiments, the case can include a first case 1b and a second case 1c, the first case 1b and the second case 1c are overlapped with each other, and the first case 1b and the second case 1c together define an accommodation space for accommodating the battery cell. The second case 1c can be a hollow structure with one end open, and the first case 1b can be a plate-like structure, which is overlapped with the open side of the second case 1c to make the first case 1b and the second case 1c together define the accommodation space; the first case 1b and the second case 1c can also be hollow structures with one side open, and the open side of the first case 1b is overlapped with the open side of the second case 1c. Of course, the case formed by the first case 1b and the second case 1c can be of various shapes, such as a cylinder, a cuboid, etc.

[0075] In some embodiments, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected with the frame, respectively, so that an enclosed space is formed inside the box to accommodate the battery monomer assembly. As an example, the frame can include a plurality of side beams.

[0076] In some embodiments, the box can be part of a chassis structure of a vehicle. For example, part of the box can be at least part of a floor of the vehicle, or part of the box can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0077] In some embodiments, the battery device 100 can be an energy storage device.

[0078] The energy storage device can be used in an energy storage power station, a wind power system, a solar power system, a mobile power system, or a temporary power supply system, etc. The energy storage device can store electrical energy as needed and output electrical energy at an appropriate time. For example, the energy storage device can store electrical energy during a low electricity consumption period, and provide electrical energy for related users or electrical equipment during a high electricity consumption period.

[0079] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0080] In some embodiments, the battery monomers are multiple, and the multiple battery monomers are connected in series or in parallel or in a hybrid manner to form a battery module 1a. Multiple battery modules 1a are connected in series or in parallel or in a hybrid manner to form an integral whole and are accommodated in the box.

[0081] The multiple battery monomers in the battery module 1a can be electrically connected through a busbar component to realize parallel connection, series connection, or hybrid connection of the multiple battery monomers in the battery module 1a. The busbar component can be one or more, and each busbar component is used to electrically connect at least two battery monomers.

[0082] Embodiments of the present application provide a battery monomer, which includes a shell and an electrode assembly accommodated in the shell.

[0083] In some embodiments, the shell can be a steel shell, an aluminum shell, or a composite metal shell (such as a copper-aluminum composite shell), etc.

[0084] The shell can be a hollow structure, and an accommodation cavity for accommodating the electrode assembly and the electrolyte is formed inside the shell.

[0085] In some embodiments, the shell of the battery monomer is a cylindrical shell, a square shell, a prismatic shell, or a shell of other shapes.

[0086] In some embodiments, the shell includes a shell body and an end cover, the shell body has an opening, and the end cover is connected to the shell body and covers the opening.

[0087] The shell is a component that cooperates with the end cap to form an internal cavity of the battery cell, which can be used to house the electrode assembly, electrolyte, and other components.

[0088] The shell and the end cap can be separate components. In an example, an opening can be provided on the shell, and the end cap can be used to cover the opening to form the internal cavity of the battery cell.

[0089] The shell can be in various shapes and sizes, such as a cuboid or a cylinder. In particular, the shape of the shell can be determined according to the specific shape and size of the electrode assembly. The shell can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0090] The shape of the end cap can be adapted to the shape of the shell to cooperate with the shell. The material of the end cap can be the same as or different from the material of the shell. Optionally, the end cap can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap is less likely to deform when subjected to extrusion and impact, and the battery cell can have higher structural strength and improved reliability.

[0091] The end cap can be connected to the shell by welding, bonding, clamping, or other means.

[0092] The shell can be open at one end or both ends. In some examples, the shell can be open at one side, and the end cap can be provided as one and cover the shell. In other examples, the shell can be open at both ends, and the end cap can be provided as two, each covering one of the openings of the shell.

[0093] The electrode assembly is a component in which electrochemical reactions occur in the battery cell. The shell can contain one or more electrode assemblies.

[0094] In some embodiments, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator, the positive electrode sheet and the negative electrode sheet being opposite in polarity, and the separator separating the positive electrode sheet and the negative electrode sheet.

[0095] At least part of the separator is located between the positive electrode sheet and the negative electrode sheet. During charging and discharging of the battery cell, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode sheet and the negative electrode sheet. The separator, which is disposed between the positive electrode sheet and the negative electrode sheet, can prevent short circuiting of the positive and negative electrodes while allowing the active ions to pass through.

[0096] In some embodiments, the positive electrode sheet can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.

[0097] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer is provided on either one or both of the two surfaces of the positive electrode current collector.

[0098] As an example, the positive electrode current collector can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, and the like can be employed. 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 (aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, a silver alloy, and the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, and the like).

[0099] As an example, the positive electrode film layer includes a positive electrode active material, and the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (such as LiCo02), lithium nickel oxide (such as LiNi02), lithium manganese oxide (such as LiMn02, LiMn204), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1O2 (may also be referred to as NCM 811 0.8 Co 0.15 Al 0.05 O2) and modified compounds thereof. The modified compounds refer to the compounds obtained by doping or coating modification of the above-mentioned substances.

[0100] In some embodiments, the negative electrode sheet can include a negative electrode current collector.

[0101] As an example, the negative electrode current collector can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, etc. can be employed. 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, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0102] As an example, the negative electrode sheet can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0103] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0104] As an example, the negative electrode film layer includes a negative electrode active material, which can employ a negative electrode active material for a battery cell known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery cell can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0105] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0106] In some embodiments, the separator includes a separator film. The separator film of the present application can employ any known porous structure film having good chemical stability and mechanical stability. ​

[0107] As an example, the main material of the separation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separation film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separation film is a multi-layer composite film, the materials of the respective layers can be the same or different.

[0108] An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can be applied to the surface of the separation film.

[0109] The separator can be a separate component located between the positive electrode sheet and the negative electrode sheet, or can be attached to the surface of the positive electrode sheet or the surface of the negative electrode sheet.

[0110] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and functions to transport ions and separate the positive and negative electrodes.

[0111] In some embodiments, the battery cell further includes an electrolyte that functions to conduct ions between the positive electrode sheet and the negative electrode sheet. The electrolyte of the present application can be selected as needed. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0112] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0113] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalate borate, lithium di-oxalate borate, lithium difluoro di-oxalate phosphate, and lithium tetrafluoro oxalate phosphate.

[0114] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether-based solvent. The ether-based solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0115] In some embodiments, the electrolyte solution can further optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and an additive capable of improving certain performance of the battery cell, such as an additive capable of improving overcharge / fast charge performance of the battery cell, an additive capable of improving high-temperature performance of the battery cell, an additive capable of improving low-temperature performance of the battery cell, and the like.

[0116] In some embodiments, the gel-state electrolyte includes a polymer as a skeleton network and can be used in combination with an ionic liquid-lithium salt.

[0117] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0118] As an example, the polymer of the polymer solid-state electrolyte can include a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid, cellulose, or the like.

[0119] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorus sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0120] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0121] In some embodiments, the electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of a wound structure and a stacked structure.

[0122] In some embodiments, the electrode assembly is a wound structure. The positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0123] In some embodiments, the electrode assembly is a stacked structure.

[0124] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be alternately stacked. As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet can be folded to form a plurality of folded segments that are stacked. One positive electrode sheet can be interposed between adjacent folded segments.

[0125] As an example, the positive electrode sheet and the negative electrode sheet can each be folded to form a plurality of folded segments that are stacked.

[0126] As an example, a plurality of separators can be provided, and each of the separators can be interposed between any adjacent positive electrode sheet or negative electrode sheet.

[0127] As an example, the separators can be continuously provided, and arranged between any adjacent positive electrode sheet or negative electrode sheet by folding or winding.

[0128] In some embodiments, the electrode assembly can have a cylindrical shape, a flat shape, or a polygonal shape.

[0129] In some embodiments, the positive current collector can include a positive tab, and the negative current collector can include a negative tab. The positive tab and the negative tab can be used to transmit electric current. As an example, at least a portion of the positive tab is not coated with the positive electrode film layer, and at least a portion of the negative tab is not coated with the negative electrode film layer.

[0130] In some embodiments, the electrode assembly has a wound structure. The positive tab is wound in multiple turns along a winding direction. Optionally, the end portion of the positive tab is bent by a flattening or smoothing process, and forms a multi-layer structure stacked in an axial direction of the electrode assembly. Optionally, the positive tab has a circular ring shape.

[0131] In some embodiments, the negative tab is wound in multiple turns along a winding direction. Optionally, the end portion of the negative tab is bent by a flattening or smoothing process, and forms a multi-layer structure stacked in an axial direction of the electrode assembly. The negative tab has a circular ring shape.

[0132] In some embodiments, the electrode assembly includes an electrode body. As an example, the electrode body includes the positive electrode film layer, the portion of the positive current collector covered with the positive electrode film layer, the negative electrode film layer, the portion of the negative current collector covered with the negative electrode film layer, and the separator.

[0133] The positive tab and the negative tab can be drawn from the same end of the electrode body, or drawn from opposite ends of the electrode body, respectively. At least a portion of the positive tab protrudes to the outside of the separator, and at least a portion of the negative tab protrudes to the outside of the separator.

[0134] Referring to Figures 3 to 5 , Figure 3 is an exploded view of a battery cell according to an embodiment of the present application; Figure 4 is a structural schematic view of an electrode assembly of a battery cell according to an embodiment of the present application; Figure 5 is a partial structural schematic view of a flattened state of an electrode assembly according to an embodiment of the present application.

[0135] As Figures 3 to 5As shown, the present application proposes a battery cell 10, which comprises a shell 1 and an electrode assembly 2. The shell 1 has a receiving cavity 11. The electrode assembly 2 is arranged in the receiving cavity 11, and the electrode assembly 2 comprises a first electrode tab 21, a separator 23 and a second electrode tab 22, the first electrode tab 21 and the second electrode tab 22 have opposite polarities, the separator 23 is used to separate the first electrode tab 21 and the second electrode tab 22, the first electrode tab 21 comprises an electrode tab body 211 and a tab 212 extending from the electrode tab body 211. In the direction of the electrode tab body 211 pointing to the tab 212, the portions of the separator 23 protruding from the electrode tab body 211 on both sides of the first electrode tab 21 are mutually fused and form a fusion portion 24. In the direction of the electrode tab body 211 pointing to the tab 212, the electrode tab body 211 is arranged in a spaced manner with the fusion portion 24

[0136] The shell 1 has a receiving cavity 11 for accommodating the electrode assembly 2, and optionally electrolyte and other components, to form an internal environment of the battery cell 10.

[0137] In some examples, the shell 1 can be in various shapes and sizes, such as one of a cuboid, a cylinder, a hexagonal prism. Specifically, the shape of the shell 1 can be determined according to the specific shape and size of the electrode assembly 2.

[0138] In some examples, the material of the shell 1 can be various, such as one or more of copper, iron, aluminum, stainless steel, aluminum alloy, plastic.

[0139] Optionally, the shell 1 is made of a material with certain hardness and strength, such as aluminum or aluminum alloy, so that the shell 1 is not easy to deform when subjected to extrusion and collision.

[0140] As an example, the shell 1 comprises an end cover and a shell body, which can be independent components, and an opening can be provided on the shell body, and the end cover is used to cover the opening to form the internal environment of the battery cell 10. Alternatively, the end cover and the shell body can be integrated, specifically, the end cover and the shell body can form a common connecting surface before other components enter the shell, and when it is necessary to encapsulate the internal environment of the shell, the end cover is used to cover the shell.

[0141] The electrode assembly 2 is a component in the battery cell 10 where electrochemical reactions occur.

[0142] In some examples, one or more electrode assemblies 2 can be contained in the shell 1.

[0143] One of the first electrode tab 21 and the second electrode tab 22 is a positive electrode tab, and the other is a negative electrode tab.

[0144] In some examples, the electrode assembly 2 can be formed by winding the positive electrode tab and the negative electrode tab, and the separator 23 is arranged between the positive electrode tab and the negative electrode tab.

[0145] The electrode assembly 2 is an example of a jelly-roll structure in which the positive electrode sheet, the separator 23, and the negative electrode sheet are wound, and the electrode assembly 2 is rectangular, and the axial direction of the electrode assembly 2 is the same as the height direction. Of course, in other embodiments, the cross section of the electrode assembly 2 perpendicular to the height direction can be elliptical or cylindrical, or the like.

[0146] In some examples, the electrode assembly 2 can be a stacked structure in which the positive electrode sheet, the separator 23, and the negative electrode sheet are stacked.

[0147] In some examples, the first electrode sheet 21 includes an electrode sheet body 211 and a tab 212 extending from the electrode sheet body 211, the electrode sheet body 211 is a region in which the electrode assembly 2 chemically reacts within the battery cell 10, and the tab 212 is connected to one end of the electrode sheet body 211, and the tab 212 is used to output or input the electric energy of the electrode assembly 2. The first electrode sheet 21 can be a positive electrode sheet, or the first electrode sheet 21 can be a negative electrode sheet.

[0148] The portions of the separators 23 protruding from the electrode sheet body 211 on both sides of the first electrode sheet 21 are fused to each other and form a fusion portion 24. It can be understood that the fusion portion 24 is a portion in which the two separators 23 are connected to each other.

[0149] Specifically, the separator 23 includes a body portion and a connection portion, and the connection portion protrudes from the electrode sheet body 211 in a direction in which the electrode sheet body 211 points to the tab 212. At least a portion of the connection portions of the separators 23 on both sides of the first electrode sheet 21 are fused to each other and form the fusion portion 24.

[0150] In some examples, a portion of the portions of the separators 23 protruding from the electrode sheet body 211 in a direction in which the electrode sheet body 211 points to the tab 212 on both sides of the first electrode sheet 21 are fused to each other and form the fusion portion 24.

[0151] In other examples, all of the portions of the separators 23 protruding from the electrode sheet body 211 in a direction in which the electrode sheet body 211 points to the tab 212 on both sides of the first electrode sheet 21 are fused to each other and form the fusion portion 24.

[0152] In some examples, the portions of the separators 23 protruding from the electrode sheet body 211 on both sides of the first electrode sheet 21 are fused to each other and form a plurality of fusion portions 24. The plurality of fusion portions 24 are arranged at intervals in a direction in which the tab 212 points to the electrode sheet body 211, and the fusion portion 24 at the end of the plurality of fusion portions 24 is arranged at an interval from the electrode sheet body 211.

[0153] In some examples, the protruding portions of the two separators 23 on both sides of the first tab 21 are fused to each other and form a plurality of fusion portions 24. The plurality of fusion portions 24 are arranged at intervals along the winding direction m of the electrode assembly 2, and each fusion portion 24 is arranged at an interval from the tab body 211.

[0154] The fusion portion 24 is arranged at an interval from the first tab 21, which can effectively reduce the heat transfer and diffusion to the tab body 211 during the heat fusion process, so as to reduce the risk of active material falling off from the first tab 21 and the influence on the electrochemical performance.

[0155] The battery cell 10 provided by the present application is provided with two separators 23 arranged on both sides of the first tab 21, and the protruding portions of the two separators 23 are fused to each other to form a fusion portion 24. The fusion portion 24 constitutes a sealing structure, which can wrap at least part of the edge of the first tab 21, effectively inhibit the edge overlap of the first tab 21 and the second tab 22, reduce the occurrence of internal short circuit of the electrode assembly 2, and improve the reliability of the battery cell 10.

[0156] For reference Figures 6 to 8 , Figure 6 is a front view of an electrode assembly of a battery cell according to an embodiment of the present application; Figure 7 is a front view of an electrode assembly of a battery cell according to another embodiment of the present application; Figure 8 is a front view of an electrode assembly of a battery cell according to still another embodiment of the present application.

[0157] According to one embodiment of the present application, as shown in Figures 6 to 8 , the fusion portion 24 is configured to be formed by laser heat fusion.

[0158] The separator 23 is subjected to heat fusion treatment by a laser generator.

[0159] The laser generator adopts a high-precision control system, which adjusts the power, frequency and wavelength of the laser to adapt to separators 23 of different materials and different specifications.

[0160] During the heat fusion process, the laser generator heats the contact area of the two layers of separators 23, so that the contact area is locally melted and fused, thereby forming the fusion portion 24.

[0161] As shown in Figures 6 to 8 , in some examples, the structure of the fusion portion 24 includes but is not limited to a columnar shape, a point shape, a ring shape, and a strip shape.

[0162] The laser heat melting forms the fusion joint 24 to firmly combine the separators 23. Compared with the particles and uneven problems that can be generated in the hot pressing process, the heat melting connection between the separators 23 can be precisely controlled by the laser, the generation of particles is reduced, the uniform fusion joint 24 is formed, and the stability of the connection quality is improved. Since the laser does not directly contact the separators 23 during the processing, the problems of belt breakage, wrinkling and stress concentration of the separators 23 are improved, so that the separators 23 have high structural integrity and processing stability.

[0163] According to one embodiment of the present application, the fusion joint 24 is arranged at one end of the separator 23 close to the tab 212.

[0164] In some examples, along the direction of the tab 212 directed to the pole piece body 211, the separator 23 includes a first connecting portion, a second connecting portion and an intermediate portion, the first connecting portion and the second connecting portion are arranged on both sides of the intermediate portion in the direction of the tab 212 directed to the pole piece body 211, and the first connecting portion is close to one end of the tab 212. The first connecting portion and the second connecting portion respectively protrude from both ends of the pole piece body 211 in the direction of the tab 212 directed to the pole piece body 211. The first connecting portions of the two separators 23 are fused to each other to form the fusion joint 24.

[0165] In some examples, the second connecting portions of the two separators 23 can be fused to each other to form the fusion joint 24; alternatively, the second connecting portions of the two separators 23 are not connected.

[0166] In some examples, the fusion joint 24 is arranged at both ends of the tab 212.

[0167] In some examples, the structures of the fusion joints 24 arranged at both ends of the tab 212 can be the same or different.

[0168] In some examples, the distances between the fusion joints 24 arranged at both ends of the tab 212 and the tab 212 are equal or different.

[0169] In some examples, the battery monomer 10 includes a plurality of fusion joints 24, and at least one fusion joint 24 is arranged at both ends of the tab 212.

[0170] Arranging the fusion joint 24 at one end close to the tab 212, the fusion joint 24 protects the first pole piece 21, reduces the contact between the two pole pieces in the high emission area, and reduces the risk of short circuit.

[0171] According to one embodiment of the present application, as shown in Figure 4 , Figures 6 to 8 The fusion joint 24 is also arranged at the other end of the separator 23 away from the tab 212.

[0172] Exemplarily, the welding portion 24 comprises a first sub-portion and a second sub-portion, the two isolation pieces 23 protrude from the portion of the pole piece main body 211 near one side of the pole lug 212 to form the first sub-portion by being welded to each other, and the two isolation pieces 23 protrude from the portion of the pole piece main body 211 far from the one side of the pole lug 212 to form the second sub-portion by being welded to each other.

[0173] Optionally, the first sub-portion and the second sub-portion have the same structure, for example, the first sub-portion and the second sub-portion are both point-shaped or strip-shaped.

[0174] Alternatively, the first sub-portion and the second sub-portion have different structures, for example, the first sub-portion is point-shaped and the second sub-portion is strip-shaped.

[0175] Both ends of the isolation piece 23 form the welding portion 24 to wrap the edges at both ends of the first pole piece 21, further reducing the risk of edge overlap of the first pole piece 21 and the second pole piece 22, and reducing the possibility of thermal runaway caused by short circuit.

[0176] For reference, Figure 8 and Figure 9 , Figure 9 is a structural schematic diagram of a flattened state of an electrode assembly of a battery cell provided by an embodiment of the present application; Figure 10 is Figure 9 an enlarged schematic view at a.

[0177] According to an embodiment of the present application, as shown in Figure 9 and Figure 10 , in the direction of the pole piece main body 211 pointing to the pole lug 212, the size R of the welding portion 24 is less than or equal to 2 mm.

[0178] In the direction of the pole piece main body 211 pointing to the pole lug 212, the size R of the welding portion 24 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, or within other ranges consisting of any two endpoints of the above.

[0179] Optionally, in the direction of the pole piece main body 211 pointing to the pole lug 212, the size R of the welding portion 24 is greater than or equal to 0.5 mm.

[0180] Exemplarily, the welding portion 24 is circular, and the diameter of the welding portion 24 is less than or equal to 2 mm.

[0181] Exemplarily, the welding portion 24 is strip-shaped in the winding direction m of the electrode assembly 2, and the width of the welding portion 24 is less than or equal to 2 mm.

[0182] The welding portion 24 has a suitable size in the compact internal environment of the battery cell 10, reduces the space occupied by the welding portion 24, reduces the amount of material of the separator 23 used for welding, and improves the processing efficiency.

[0183] According to one embodiment of the present application, as shown in Figure 9 and Figure 10 In the direction in which the tab body 211 points to the tab 212, the welding portion 24 is spaced apart from the edge of the separator 23 on the side close to the welding portion 24.

[0184] In some examples, the portions of the separator 23 protruding from the tab body 211 on both sides of the first tab 21 are welded to each other and form a plurality of welding portions 24. The plurality of welding portions 24 are spaced apart in the direction in which the tab body 211 points to the tab 212, and the welding portion 24 at the end of the plurality of welding portions 24 is spaced apart from the edge of the separator 23.

[0185] In some examples, the portions of the separator 23 protruding from the tab body 211 on both sides of the first tab 21 are welded to each other and form a plurality of welding portions 24. The plurality of welding portions 24 are spaced apart in the winding direction m of the electrode assembly 2, and each welding portion 24 is spaced apart from the edge of the separator 23.

[0186] Optionally, in the direction in which the tab body 211 points to the tab 212, the welding portion 24 is located in the middle region of the portion of the separator 23 protruding from the tab body 211.

[0187] In some examples, in the direction in which the tab body 211 points to the tab 212, the welding portion 24 is spaced apart from the edge of the separator 23 on the side close to the welding portion 24, and the welding portion 24 is spaced apart from the tab body 211.

[0188] Optionally, in the direction in which the tab body 211 points to the tab 212, the spacing L1 between the welding portion 24 and the edge of the separator 23 on the side close to the welding portion 24 is equal to the spacing L2 between the welding portion 24 and the tab body 211.

[0189] The welding portion 24 is spaced apart from the edge of the separator 23, which reserves a fault-tolerant space and improves the production efficiency.

[0190] According to one embodiment of the present application, as shown in Figure 9 and Figure 10 In the direction in which the tab body 211 points to the tab 212, the spacing L1 between the welding portion 24 and the edge of the separator 23 on the side close to the welding portion 24 is less than or equal to 1 mm.

[0191] In the direction in which the tab body 211 points to the tab 212, the distance L1 between the fusion portion 24 and the edge of the separator 23 close to the fusion portion 24 side is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, or within a range defined by any two of the above endpoints.

[0192] Optionally, in the direction in which the tab body 211 points to the tab 212, the distance L1 between the fusion portion 24 and the edge of the separator 23 close to the fusion portion 24 side is greater than or equal to 0.5 mm.

[0193] The distance L1 between the fusion portion 24 and the edge of the separator 23 is less than or equal to 1 mm. The fusion portion 24 is a stable connection structure formed by fusion of the separator 23, which can effectively disperse the stress in the edge area, improve the excessive concentration of stress in the edge, and reduce the risk of fracture or belt breakage of the separator 23.

[0194] According to one embodiment of the present application, as shown in Figure 9 and Figure 10 In the direction in which the tab body 211 points to the tab 212, the distance L2 between the fusion portion 24 and the tab body 211 is less than or equal to 1 mm.

[0195] In some examples, in the direction in which the tab body 211 points to the tab 212, the distances between the fusion portion 24 and the tab body 211 are all equal.

[0196] Exemplarily, the fusion portion 24 is in a strip shape along the winding direction m of the electrode assembly 2, and the distance L2 between the fusion portion 24 and the tab body 211 is less than or equal to 1 mm.

[0197] In other examples, in the direction in which the tab body 211 points to the tab 212, the minimum distance between the fusion portion 24 and the tab body 211 is less than or equal to 1 mm.

[0198] Exemplarily, the fusion portion 24 is in a circular shape, and the distance L2 between the fusion portion 24 and the tab body 211 is less than or equal to 1 mm.

[0199] In the direction in which the tab body 211 points to the tab 212, the distance L2 between the fusion portion 24 and the tab body 211 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, or within a range defined by any two of the above endpoints.

[0200] Optionally, the distance L2 between the welding portion 24 and the tab body 211 in the direction in which the tab body 211 points to the tab 212 is greater than or equal to 0.5 mm.

[0201] The appropriate distance between the welding portion 24 and the tab body 211 reduces the redundancy of the separator 23 and improves the space utilization inside the battery monomer 10.

[0202] Referring to Figure 11 illustrated, Figure 11 The application provides a cross-sectional structure schematic diagram of a winding structure of a battery monomer.

[0203] According to an embodiment of the application, as Figure 11 illustrated, the first tab 21, the separator 23 and the second tab 22 are wound to form a bending area W and a flat area P connected to the bending area W. The welding portion 24 is arranged at least in the flat area P.

[0204] In some examples, the battery monomer 10 includes a plurality of electrode assemblies 2 stacked along a first direction x.

[0205] Illustratively, the electrode assembly 2 includes the first tab 21, the second tab 22 and two separators 23, the two separators 23 are respectively arranged on both sides of the first tab 21, the first tab 21, the second tab 22 and the separators 23 are wound around a winding axis to form a winding structure and form a bending area W and a flat area P connected to the bending area W. The flat area P and the bending area W are arranged along a second direction y, and the first direction x is perpendicular to the second direction y.

[0206] Specifically, the wound first tab 21 includes a plurality of first tab 21 flat portions and a plurality of first tab 21 bending portions, the plurality of first tab 21 flat portions are arranged in a stack along the first direction x, and each first tab 21 bending portion is at least partially bent into an arc shape and connected to the flat portions of two adjacent first tabs 21. At least one first tab 21 flat portion is arranged opposite to at least one welding portion 24.

[0207] Optionally, each first tab 21 flat portion is arranged opposite to at least one welding portion 24.

[0208] More optionally, each first tab 21 flat portion is arranged opposite to a plurality of welding portions 24.

[0209] Two separators 23 are arranged on both sides of the first tab 21 to form a basic unit. The separators 23 need to be tightly attached to the first tab 21 to reduce the problem of structural instability caused by poor attachment during winding. By using a laser generator, the contact area of the two separators 23 is heated, that is, along the direction of the tab main body 211 pointing to the tab 212, the part of the separators 23 protruding from the tab main body 211 on both sides of the first tab 21 is locally melted and fused to form a fusion portion 24, and the two separators 23 are firmly combined, which improves the problem of particulate matter and uneven sealing that may occur in the traditional hot pressing method.

[0210] The fusion portion 24 can tightly fix the separators 23 on both sides of the first tab 21, so that a reliable mechanical support is formed between the two separators 23 and the first tab 21, and the electrode assembly 2 after winding has higher structural stability. In the same volume, more electrode materials can be arranged to withstand greater working current and higher energy density, thereby improving the overall performance and service life of the battery cell 10.

[0211] According to one embodiment of the present application, as shown in Figure 11 The fusion portion 24 is also arranged in the bending area W.

[0212] In some examples, the parts of the separators 23 protruding from the tab main body 211 on both sides of the first tab 21 are fused with each other and form one fusion portion 24, one part of the fusion portion 24 is located in the flat area P, and the other part is located in the bending area W.

[0213] In other examples, the parts of the separators 23 protruding from the tab main body 211 on both sides of the first tab 21 are fused with each other and form a plurality of fusion portions 24, at least one fusion portion 24 is located in the flat area P, and at least one fusion portion 24 is located in the bending area W.

[0214] Exemplarily, the total area of the fusion portion 24 located in the flat area P is greater than the total area of the fusion portion 24 located in the bending area W.

[0215] According to one embodiment of the present application, as shown in Figure 11 The fusion portion 24 extends along the winding direction m of the separator 23.

[0216] Exemplarily, the first tab 21, the separator 23 and the second tab 22 form a wound structure after winding, the fusion portion 24 extends along the winding direction m of the separator 23, the starting end of the fusion portion 24 exceeds the starting end of the first tab 21, and the end of the fusion portion 24 exceeds the end of the first tab 21.

[0217] Optionally, the fusion portion 24 extends along the winding direction m of the separator 23 to form a strip shape.

[0218] The welding portion 24 extending along the winding direction m is consistent with the extending direction of the separator 23 and the first electrode sheet 21 to form a linear continuous sealing edge structure. The first electrode sheet 21 is more uniformly bound between the separators 23 on both sides, providing a coherent mechanical constraint for the winding structure, reducing the risk of local loosening or edge lifting, and also reducing the risk of interlayer slippage.

[0219] With reference to Figure 12 and Figure 13 , Figure 12 a partial structure schematic diagram of an electrode assembly of a battery cell provided by an embodiment of the present application is provided; Figure 13 a partial structure schematic diagram of an electrode assembly of a battery cell provided by an embodiment of the present application is provided.

[0220] According to an embodiment of the present application, as Figure 4 , Figures 11 to 13 shown, the battery cell 10 includes a plurality of welding portions 24, and the plurality of welding portions 24 are arranged at intervals along the winding direction m of the separator 23.

[0221] Exemplarily, the battery cell 10 includes a plurality of welding portion groups, the plurality of welding portion groups are arranged at intervals along the winding direction m of the separator 23, the plurality of welding portion groups include a plurality of welding portions 24, and the plurality of welding portions 24 are arranged at intervals along a direction in which the electrode sheet body 211 points to the tab 212.

[0222] The channel between the two welding portions 24 can be used as a channel for electrolyte penetration, so that the electrolyte can more quickly and uniformly diffuse to the entire battery cell 10, improving the stability of ion conduction.

[0223] In a second aspect, the present application provides a battery device, including the battery cell according to the foregoing.

[0224] In a third aspect, the present application provides a use-electric device, including the battery cell according to the foregoing or the battery device according to the foregoing, and the battery cell or the battery device is used for storing or providing electric energy.

[0225] According to some embodiments of the present application, as Figures 3 to 13 shown, the present application provides a battery cell 10, the battery cell 10 includes a housing 1 and an electrode assembly 2, and the housing 1 has a receiving cavity 11. The electrode assembly 2 is arranged in the receiving cavity 11, and the electrode assembly 2 includes a first electrode sheet 21, a separator 23 and a second electrode sheet 22, the polarities of the first electrode sheet 21 and the second electrode sheet 22 are opposite, and the separator 23 is used to separate the first electrode sheet 21 and the second electrode sheet 22. The first electrode sheet 21 includes an electrode sheet body 211 and a tab 212 extending from the electrode sheet body 211, and along a direction in which the electrode sheet body 211 points to the tab 212, the first electrode sheet 21, the separator 23 and the second electrode sheet 22 are wound to form a bending area W and a flat area P connected to the bending area W.

[0226] The portions of the separators 23 protruding from the pole piece main body 211 on both sides of the first pole piece 21 are fusion-bonded to each other and form fusion-bonded portions 24. The fusion-bonded portions 24 are configured to be formed by laser heat fusion. The fusion-bonded portions 24 extend in the winding direction m of the separators 23. The flat regions P and the bent regions W are each provided with the fusion-bonded portions 24. The fusion-bonded portions 24 are provided at both ends of the separators 23 in the direction in which the pole piece main body 211 points toward the tab 212.

[0227] In the direction in which the pole piece main body 211 points toward the tab 212, the size of the fusion-bonded portions 24 is less than or equal to 2 mm.

[0228] In the direction in which the pole piece main body 211 points toward the tab 212, the distance L1 between the fusion-bonded portions 24 and the edge of the separators 23 on the side close to the fusion-bonded portions 24 is less than or equal to 1 mm. In the direction in which the pole piece main body 211 points toward the tab 212, the distance L2 between the fusion-bonded portions 24 and the pole piece main body 211 is less than or equal to 1 mm.

[0229] Although the present application has been described with reference to the preferred embodiments, various modifications are possible in light of the above teachings, and the present application is not limited to the specific embodiments disclosed herein but rather includes any and all variations falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The battery cell comprises: a housing having a receiving cavity; an electrode assembly disposed in the receiving cavity, the electrode assembly comprising a first tab, a separator, and a second tab, the first tab and the second tab having opposite polarities, the separator being configured to separate the first tab and the second tab, the first tab comprising a tab body and a tab lug extending from the tab body, the portions of the separator on both sides of the tab body in a direction of the tab body pointing to the tab lug being fused to each other and forming a fusion portion, the tab body being spaced apart from the fusion portion in the direction of the tab body pointing to the tab lug.

2. The battery cell according to claim 1, wherein the fusion portion is configured to be formed by laser heat fusion.

3. The battery cell according to claim 1, wherein the fusion portion is disposed at an end of the separator close to the tab lug in a direction of the tab body pointing to the tab lug.

4. The battery cell according to claim 3, wherein the fusion portion is further disposed at another end of the separator away from the tab lug in the direction of the tab body pointing to the tab lug.

5. The battery cell according to claim 1, wherein a size R of the fusion portion is less than or equal to 2 mm in the direction of the tab body pointing to the tab lug.

6. The battery cell according to claim 1, wherein the fusion portion is spaced apart from an edge of the separator close to the fusion portion in the direction of the tab body pointing to the tab lug.

7. The battery cell according to claim 6, wherein a distance L1 between the fusion portion and the edge of the separator close to the fusion portion is less than or equal to 1 mm in the direction of the tab body pointing to the tab lug.

8. The battery cell according to claim 1, wherein a distance L2 between the tab body and the fusion portion is less than or equal to 1 mm in the direction of the tab body pointing to the tab lug.

9. The battery cell according to claim 1, wherein the first tab, the separator, and the second tab are wound to form a bending region and a flat region connected to the bending region; the fusion portion is disposed at least in the flat region.

10. The battery cell according to claim 9, wherein the fusion portion is further disposed in the bending region.

11. The battery cell according to claim 1, wherein the fusion portion extends in a winding direction of the separator.

12. The battery cell according to claim 1, wherein the battery cell comprises a plurality of the fusion portions, the plurality of the fusion portions being spaced apart in the winding direction of the separator.

13. A battery device characterized by comprising: a plurality of the battery cells according to any one of claims 1 to 12.

14. An electrical device, characterized by a battery cell according to any one of claims 1 to 12 or a battery device as claimed in claim 13, the battery cell or the battery device being used for storing or providing electrical energy.

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