Battery cell, battery device, and electric device

Abstract

The application relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell and an electrode assembly. The shell has a containing cavity. The electrode assembly is arranged in the containing cavity and comprises a first pole piece, a second pole piece and a separator. The first pole piece comprises a first current collector, a first active material layer, an insulating layer and an insulating film. The first current collector comprises a current collection main body and a pole lug arranged along a first direction. The first active material layer is arranged on the current collection main body. At least part of the insulating layer is arranged on the current collection main body and located on a side of the first active material layer close to the pole lug. In a thickness direction, at least part of the insulating film is located on a side of the insulating layer away from the current collection main body and attached to the insulating layer. In a direction of the current collection main body pointing to the pole lug, the insulating film protrudes from an end surface of the current collection main body facing the pole lug and an end surface of the insulating layer away from the first active material layer. The battery monomer provided by the application can separate burrs of the end surface of the current collection main body facing the pole lug from the separator.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to battery cells, battery devices, and electrical devices. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and rechargeable alkaline zinc-manganese batteries, among others.

[0003] In the development of batteries, how to ensure the reliability of individual battery cells is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This application provides a battery cell, a battery device, and an electrical device, which aim to improve the reliability of the battery cell to a certain extent.

[0005] In a first aspect, this application proposes a battery cell, which includes a casing and an electrode assembly. The casing has a receiving cavity. The electrode assembly is disposed within the receiving cavity and includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities, and the separator is used to isolate the first electrode and the second electrode. The first electrode includes a first current collector, a first active material layer, an insulating layer, and an insulating film. The first current collector includes a current collector body and a tab disposed along a first direction. The first active material layer is disposed on the current collector body, and at least a portion of the insulating layer is disposed on the current collector body and located on the side of the first active material layer near the tab. In the thickness direction of the current collector body, at least a portion of the insulating film is located on the side of the insulating layer away from the current collector body and is attached to the insulating layer. The first direction is perpendicular to the thickness direction. Along the direction from the current collector body to the tab, the insulating film protrudes from the end face of the current collector body facing the tab and the end face of the insulating layer away from the first active material layer.

[0006] The battery cell provided in this application has an insulating film that separates burrs on the end face of the current collector facing the electrode tab from the separator, reducing the risk of burrs piercing the separator, decreasing the possibility of thermal runaway caused by short circuits, and improving the reliability of the battery cell. Furthermore, the current collector is provided with an insulating film and an insulating layer to form double-layer insulation protection, which can both reduce the occurrence of short circuits and protect the first active material layer, further improving the reliability of the battery cell.

[0007] According to one embodiment of this application, the insulating film does not overlap with the first active material layer in the thickness direction.

[0008] In these alternative embodiments, during the battery charging and discharging process, the expansion and contraction of the active material layer will cause compression or friction on the insulating film. Therefore, in the thickness direction, the insulating film does not overlap with the first active material layer, which improves the stability of the insulating film.

[0009] According to one embodiment of this application, in a first direction, the end of the insulating film facing the first active material layer is spaced apart from the first active material layer.

[0010] In these alternative embodiments, the insulating film and the first active material layer are spaced apart. The spaced arrangement between the insulating film and the first active material layer can provide more flow channels for the liquid electrolyte, thereby reducing the obstruction of the insulating film to the liquid electrolyte and allowing the liquid electrolyte to penetrate more evenly into all parts of the first active material layer.

[0011] According to one embodiment of this application, in a first direction, the distance between the insulating film and the first active material layer is greater than or equal to 1 mm.

[0012] In these alternative embodiments, the insulating film has a suitable spacing from the first active material layer to reduce the amount of insulating film used.

[0013] According to one embodiment of this application, an insulating layer is provided on both sides of the current collector body along the thickness direction, and an insulating film is attached to the side of each insulating layer facing away from the current collector body.

[0014] In these alternative embodiments, two insulators can separate the burrs on the end face of the current collector from the isolation elements on both sides, thereby further reducing the risk of short circuits.

[0015] According to one embodiment of this application, the portions of the two insulating films protruding from the end faces of the current collector body facing the tab are bonded together.

[0016] In these alternative embodiments, bonding the portions of the two insulating films that protrude from the end faces of the current collector facing the tabs can reduce the risk of the insulating films falling off and can also cover at least part of the burrs on the end faces between the two insulating films.

[0017] According to one embodiment of this application, the insulating film includes a first insulating portion and a second insulating portion arranged along a first direction. The first insulating portion is attached to the insulating layer and overlaps with the current collector in the thickness direction. The second insulating portion is located on the side of the first insulating portion near the tab.

[0018] In these alternative embodiments, the first insulating portion can have a large connection area with the insulating layer, reducing the risk of the insulating film detaching. The second insulating portion can separate the burrs of the current collector from the isolator, thereby reducing the risk of short circuit.

[0019] According to one embodiment of this application, a portion of the second insulating portion overlaps with the tab along the thickness direction.

[0020] In these alternative embodiments, the second insulating portion can support the tab, reducing the risk of the tab being inserted upside down between the first and second pole pieces when bent, thereby reducing the risk of short circuit and improving reliability.

[0021] According to one embodiment of this application, the second insulating portion includes a first sub-portion and a second sub-portion arranged along a second direction, the first sub-portion overlapping the electrode tab along the thickness direction, the second direction being perpendicular to the first direction and the thickness direction; the second sub-portion is connected to the first sub-portion and the first insulating portion.

[0022] In these alternative embodiments, the second insulating portion can shield some of the burrs formed during the forming process of the tab, thereby reducing the risk of short circuit.

[0023] According to one embodiment of this application, the second sub-parts of two insulating films opposite each other along the thickness direction are connected.

[0024] According to one embodiment of this application, the insulating layer includes a first region and a second region. The first region is disposed on the current collector body, and the second region is connected to the first region. The second region is disposed on the electrode tab, and the electrode tab protrudes from the insulating layer along a first direction. A first insulating portion is attached to the first region, and a second insulating portion is attached to the second region.

[0025] In these alternative embodiments, the second region of the insulating layer can provide effective support for the tab, reducing the risk of the first tab being inserted upside down between the first and second electrodes. The insulating layer can also provide insulation, effectively limiting the deformation of the tab.

[0026] According to one embodiment of this application, in a first direction, the size m of the second insulating portion and the size n of the second region satisfy: 0mm≤nm≤2mm.

[0027] In these alternative embodiments, the use of insulating film is reduced, and the internal space of the battery cell is made more efficient to improve the energy density of the battery cell.

[0028] According to one embodiment of this application, in a first direction, the size n of the second region is 1 mm to 20 mm.

[0029] In these alternative embodiments, the insulating layer has a suitable size on the tab, and the use of the insulating layer is appropriately reduced while still supporting the tab, thereby increasing the energy density of the battery cell.

[0030] According to one embodiment of this application, the misalignment of the two insulating films in a first direction is less than or equal to 0.6 mm.

[0031] In these alternative embodiments, the arrangement is such that the overlapping area between the two insulating films in the first direction can maintain stable insulation performance.

[0032] According to one embodiment of this application, in a first direction, the dimension m of the insulating film protruding from the end face of the current collector body facing the tab satisfies: 0.5mm ≤ c ≤ 2mm.

[0033] In these alternative embodiments, this arrangement can reduce the use of the insulating film and also reduce the interference of the insulating film on the tabs.

[0034] According to one embodiment of this application, the thickness of the insulating film is 9 μm to 30 μm.

[0035] In these alternative embodiments, limiting the thickness of the insulating layer to greater than or equal to 7 μm reduces the risk of the insulating layer being punctured by burrs, thereby improving reliability. Limiting the thickness of the insulating layer to less than or equal to 30 μm reduces the space and weight occupied by the insulating layer, thereby reducing the energy density loss of the battery cells.

[0036] According to one embodiment of this application, in a first direction, the size of the insulating layer on the current collector is 2 mm to 4 mm.

[0037] In these alternative embodiments, limiting the size of the insulating layer on the current collector to greater than or equal to 2 mm can improve insulation performance. Limiting the size of the insulating layer on the current collector to less than or equal to 4 mm can reduce the space and weight occupied by the insulating layer, thereby increasing the proportion of the first active material layer on the current collector and thus improving the energy density of the battery cell.

[0038] According to one embodiment of this application, the insulating layer comprises ceramic.

[0039] According to one embodiment of this application, the first electrode is a positive electrode.

[0040] Secondly, this application provides a battery device including the aforementioned battery cell.

[0041] Thirdly, this application provides an electrical device, including a battery cell or a battery device as described above, wherein the battery cell or battery device is used to store or provide electrical energy.

[0042] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0043] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0044] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0045] Figure 2 This is an exploded view of a battery device provided in an embodiment of this application;

[0046] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application;

[0047] Figure 4 This is a top view of an electrode assembly provided in an embodiment of this application;

[0048] Figure 5 for Figure 4 A partial sectional view along the aa direction;

[0049] Figure 6 for Figure 4 A partial sectional view along the bb direction;

[0050] Figure 7 This is a schematic diagram of the first electrode sheet without an insulating film in a flattened state according to an embodiment of this application;

[0051] Figure 8 This is a schematic diagram of the first electrode sheet provided in an embodiment of this application in a flattened state.

[0052] The accompanying drawings may not be drawn to scale.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1000, vehicles;

[0055] 100. Battery assembly; 200. Controller; 300. Motor;

[0056] 1a. Battery module; 1b. First housing; 1c. Second housing;

[0057] 10. Battery cells;

[0058] 1. Outer shell; 11. Receiving cavity;

[0059] 2. Electrode assembly; 2a. First electrode; 21. First current collector; 211. Current collector body; 212. Tab; 22. First active material layer; 23. Insulating layer; 231. First region; 232. Second region; 24. Insulating film; 241. First insulating part; 242. Second insulating part; 2421. First sub-part; 2422. Second sub-part; 2b. Second electrode; 2c. Isolator;

[0060] x, first direction; y, second direction; z, thickness direction. Detailed Implementation

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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 three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0066] 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.

[0067] In this application, "multiple" means two or more (including two).

[0068] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields.

[0069] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0070] In the fabrication of electrodes (positive or negative electrodes), cutting (e.g., electrode slitting or tab die-cutting) is typically required to achieve the desired size and shape. However, after cutting, burrs are easily generated at the cutting locations on the current collector; during the charging and discharging of the battery cell, these burrs may puncture the separator, causing the positive and negative electrodes to conduct, leading to a short circuit risk and affecting the reliability of the battery cell. The above statements are for providing background information related to this application only and do not necessarily constitute prior art.

[0071] The battery cell provided in this application has an insulating film that separates burrs on the end face of the current collector facing the electrode tab from the separator, reducing the risk of burrs piercing the separator, decreasing the possibility of thermal runaway caused by short circuits, and improving the reliability of the battery cell. Furthermore, the current collector is provided with an insulating film and an insulating layer to form double-layer insulation protection, which can both reduce the occurrence of short circuits and protect the first active material layer, further improving the reliability of the battery cell.

[0072] The battery cell described in this application is applicable to batteries and electrical devices that use batteries. This battery cell can be used, but is not limited to, batteries, and can also be used in products such as vehicles, aircraft, ships, electronic devices, and power tools, thereby improving the reliability of these products.

[0073] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, among others. 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.

[0074] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0075] 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.

[0076] Please refer to Figure 2 , Figure 2 Exploded views of battery devices provided in some embodiments of this application.

[0077] In some embodiments, the battery device 100 may include one or more battery cell assemblies for providing voltage and capacity.

[0078] 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.

[0079] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0080] As an example, a single 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-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0081] As an example, a battery cell can be 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.

[0082] 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 1a, which is formed by arranging and fixing multiple battery cells to form an independent module. As an example, a battery module 1a can be formed by bundling multiple battery cells together with cable ties.

[0083] In some embodiments, the battery device 100 may be a battery pack, which includes a housing and one or more battery cell assemblies housed within the housing. As an example, the battery cell assembly may be a battery module 1a, which can be housed within the housing by securing the battery module 1a to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0084] In some embodiments, the housing is used to house individual battery cells, and the housing can have various structures.

[0085] In some embodiments, the housing may include a first housing 1b and a second housing 1c, which overlap each other, and together define a receiving space for accommodating a single battery cell. The second housing 1c may be a hollow structure with one open end, and the first housing 1b may be a plate-like structure, with the first housing 1b covering the open side of the second housing 1c so that the first housing 1b and the second housing 1c together define the receiving space. Alternatively, both the first housing 1b and the second housing 1c may be hollow structures with one open side, with the open side of the first housing 1b covering the open side of the second housing 1c. Of course, the housing formed by the first housing 1b and the second housing 1c can be of various shapes, such as a cylinder, a cuboid, etc.

[0086] In some embodiments, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the enclosure to house the individual battery cells. As an example, the frame may include multiple side beams.

[0087] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0088] In some embodiments, the battery device 100 may be an energy storage device.

[0089] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0090] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0091] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application.

[0092] In some embodiments, there are multiple battery cells 10, which are first connected in series, parallel, or mixed to form a battery module 1a. The multiple battery modules 1a are then connected in series, parallel, or mixed to form a whole and housed in a housing.

[0093] Multiple battery cells 10 in battery module 1a can be electrically connected through a busbar to achieve parallel, series, or mixed connection of the multiple battery cells 10 in battery module 1a. There can be one or more busbars, and each busbar is used to electrically connect at least two battery cells 10.

[0094] This application provides a battery cell 10, which includes a housing and an electrode assembly 10 housed within the housing.

[0095] In some embodiments, the outer casing may be a steel casing, an aluminum casing, or a composite metal casing (such as a copper-aluminum composite casing).

[0096] The outer shell can be a hollow structure, with an internal cavity for accommodating the electrode assembly 10 and the electrolyte.

[0097] In some embodiments, the casing of the battery cell 10 is a cylindrical casing, a square casing, a prismatic casing, or a casing of other shapes.

[0098] In some embodiments, the housing includes a housing and an end cap, the housing having an opening and the end cap being connected to the housing and covering the opening;

[0099] The housing is a component used to fit the end cap to form the internal cavity of the battery cell 10, which can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0100] The housing and end cap can be separate components. For example, an opening can be provided on the housing, and the end cap can be used to close the opening to form an internal cavity for the battery cell 10.

[0101] The housing can be of various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the housing can be determined according to the specific shape and size of the electrode assembly 10. The housing can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0102] The shape of the end cap can be adapted to the shape of the housing to fit the housing. The material of the end cap can be the same as or different from that of the housing. Optionally, the end cap can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap is not easily deformed when subjected to compression and impact, so that the battery cell 10 can have higher structural strength and improve reliability.

[0103] The end caps are attached to the housing by welding, bonding, snap-fitting, or other means.

[0104] The housing may be open at one end or at both ends. In some examples, the housing may be a structure with an opening on one side, with one end cap fitting over the housing. In other examples, the housing may be a structure with openings on both sides, with two end caps fitting over the two openings of the housing, respectively.

[0105] Electrode assembly 10 is a component in the battery cell 10 where electrochemical reactions occur. The housing may contain one or more electrode assemblies 10.

[0106] In some embodiments, the electrode assembly 10 includes a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode have opposite polarities, and the separator separates the positive electrode and the negative electrode.

[0107] At least a portion of the separator is located between the positive and negative electrode plates. During the charging and discharging process of the battery cell 10, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrode plates. The separator, positioned between the positive and negative electrode plates, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0108] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0109] As an example, the positive current collector has two surfaces opposite each other in thickness, and the positive electrode film layer is disposed on either or both of the opposite surfaces of the positive current collector.

[0110] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0111] As an example, the positive electrode film layer includes a positive electrode active material, which 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 for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate 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 oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 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 0.2O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0112] In some embodiments, the negative electrode may include a negative current collector.

[0113] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0114] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0115] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0116] As an example, the negative electrode film layer includes a negative electrode active material, which 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.

[0117] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0118] In some embodiments, the separator includes a separator membrane. The separator membrane in this application can be any known porous membrane with good chemical and mechanical stability.

[0119] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.

[0120] Inorganic particle coating, organic particle coating, or organic / inorganic composite coating can also be applied to the surface of the separator.

[0121] The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surface of the positive or negative electrode.

[0122] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0123] In some embodiments, the battery cell 10 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0124] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0125] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0126] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0127] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0128] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0129] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0130] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0131] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0132] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0133] In some embodiments, the electrode assembly 10 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0134] In some embodiments, the electrode assembly 10 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0135] In some embodiments, the electrode assembly 10 has a stacked structure.

[0136] As an example, multiple positive and negative electrode plates can be set, with multiple positive and multiple negative electrode plates stacked alternately. As an example, multiple positive electrode plates can be set, and negative electrode plates are folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0137] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0138] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0139] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0140] In some embodiments, the positive current collector may include a positive tab, and the negative current collector may include a negative tab. The positive and negative tabs can be used to transmit current. As an example, at least a portion of the positive tab is not coated with a positive film layer, and at least a portion of the negative tab is not coated with a negative film layer.

[0141] See Figures 4 to 6 , Figure 4 This is a top view of an electrode assembly provided in an embodiment of this application; Figure 5 for Figure 4 A partial sectional view along the aa direction; Figure 6 for Figure 4 A partial sectional view along the bb direction.

[0142] like Figures 3 to 6 As shown, this application proposes a battery cell, which includes a housing 1 and an electrode assembly 2. The housing 1 has a receiving cavity 11. The electrode assembly 2 is disposed within the receiving cavity 11 and includes a first electrode 2a, a second electrode 2b, and a separator 2c. The first electrode 2a and the second electrode 2b have opposite polarities, and the separator 2c is used to isolate the first electrode 2a and the second electrode 2b. The first electrode 2a includes a first current collector 21, a first active material layer 22, an insulating layer 23, and an insulating film 24. The first current collector 21 includes a current collector body 211 and a tab 212 disposed along a first direction x. The first active material layer 22 is disposed on the current collector body 211. At least a portion of the insulating layer 23 is disposed on the current collector body 211 and located on the side of the first active material layer 22 near the tab 212. In the thickness direction z of the current collector body 211, at least a portion of the insulating film 24 is located on the side of the insulating layer 23 away from the current collector body 211 and is attached to the insulating layer 23. The first direction x is perpendicular to the thickness direction z. Along the direction from the current collector body 211 to the tab 212, the insulating film 24 protrudes from the end face of the current collector body 211 facing the tab 212 and the end face of the insulating layer 23 away from the first active material layer 22.

[0143] In some examples, the housing 1 may contain one or more electrode assemblies 2.

[0144] Electrode assembly 2 is the component in the battery cell where electrochemical reactions occur.

[0145] In some examples, the electrode assembly 2 is formed by winding a first electrode 2a and a second electrode 2b, and typically a spacer 2c is provided between the first electrode 2a and the second electrode 2b.

[0146] In other examples, the electrode assembly 2 is a stacked structure formed by layering a first electrode 2a, an insulating element 2c, and a second electrode 2b.

[0147] For example, the electrode assembly 2 is a wound structure formed by winding a first electrode 2a, a spacer 2c, and a second electrode 2b, and the electrode assembly 2 is rectangular, with its axial direction being the same as its height direction. Of course, in other examples, the cross-section of the electrode assembly 2 perpendicular to the height direction can also be elliptical or cylindrical, etc.

[0148] In some examples, the first electrode 2a can be a positive electrode, or the first electrode 2a can be a negative electrode.

[0149] The first electrode 2a includes a first current collector 21, a first active material layer 22, and an insulating layer 23. The first current collector 21 includes a current collector body 211 and a tab 212 disposed along a first direction x. The first active material layer 22 and the insulating layer 23 are disposed on at least one surface of the current collector body 211, and at least a portion of the insulating layer 23 is disposed on the current collector body 211 and located on the side of the first active material layer 22 near the tab 212. It can be understood that the first active material layer 22 and the insulating layer 23 are arranged along the direction from the current collector body 211 to the tab 212.

[0150] The direction along the collector body 211 pointing to the tab 212 is parallel to the first direction x.

[0151] In some examples, the first electrode 2a includes a first current collector 21, two first active material layers 22 and an insulating layer 23. The first current collector 21 includes a current collector body 211 and a tab 212 disposed along a first direction x. The two first active material layers 22 are disposed on two surfaces of the current collector body 211 along the thickness direction z. The insulating layer 23 is disposed on one surface of the current collector body 211, and at least a portion of the insulating layer 23 is disposed on the current collector body 211 and located on the side of the first active material layer 22 near the tab 212.

[0152] In other examples, the first electrode 2a includes a first current collector 21, two first active material layers 22 and an insulating layer 23. The first current collector 21 includes a current collector body 211 and a tab 212 disposed along a first direction x. The two first active material layers 22 are disposed on two surfaces of the current collector body 211 along the thickness direction z. The insulating layer 23 is disposed in a ring along the outer peripheral surface of the current collector body 211, and at least a portion of the insulating layer 23 is disposed on the current collector body 211 and located on the side of the first active material layer 22 near the tab 212.

[0153] In some other examples, the first electrode 2a includes a first current collector 21, two first active material layers 22 and two insulating layers 23. The first current collector 21 includes a current collector body 211 and a tab 212 disposed along a first direction x. The two first active material layers 22 and the two insulating layers 23 are respectively disposed on two surfaces of the current collector body 211 along the thickness direction z, and at least a portion of the insulating layer 23 is disposed on the current collector body 211 and located on the side of the first active material layer 22 near the tab 212.

[0154] The insulating film 24 can be connected to the current collector 211 in various ways. For example, the insulating film 24 can be connected to the current collector 211 by adhesive bonding; alternatively, the insulating film 24 can be connected to the current collector 211 by attachment.

[0155] In some examples, the insulating film 24 can be one or more, with multiple spacings arranged on the current collection body 211.

[0156] In some embodiments, the insulating film 24 may be in the form of a sheet, block, strip, or other irregular shape.

[0157] Along the direction from the current collector 211 to the tab 212, the insulating film 24 protrudes from the end face of the current collector 211 facing the tab 212 and the end face of the insulating layer 23 facing away from the first active material layer 22. It can be understood that the insulating film 24 includes a first part and a second part connected together. The first part is attached to the insulating layer 23, and the second part protrudes from the end face of the current collector 211 facing the tab 212 and the end face of the insulating layer 23 facing away from the first active material layer 22 along the direction from the current collector 211 to the tab 212.

[0158] In some examples, along the direction from the current collector 211 to the tab 212, the end face of the current collector 211 facing the tab 212 is flush with the end face of the insulating layer 23 facing away from the first active material layer 22. This arrangement facilitates the die-cutting of the tab 212 and the insulating layer 23.

[0159] In other examples, along the direction from the current collector 211 to the tab 212, the end face of the insulating layer 23 facing away from the first active material layer 22 protrudes from the end face of the current collector 211 facing the tab 212. This configuration allows the insulating layer 23 to provide some protection to the current collector 211, reducing the probability of burrs piercing the separator 2c.

[0160] The battery cell provided in this application has an insulating film 24 that separates the burrs on the end face of the current collector 211 facing the tab 212 from the separator 2c, reducing the risk of burrs piercing the separator 2c, decreasing the possibility of thermal runaway caused by short circuits, and improving the reliability of the battery cell. Furthermore, the current collector 211 is provided with an insulating film 24 and an insulating layer 23 to form a double-layer insulation protection, which can reduce the occurrence of short circuits and protect the first active material layer 22, further improving the reliability of the battery cell.

[0161] Furthermore, when the insulating film 24 is directly connected to the current collector 211, high temperatures during battery charging and discharging may cause the insulating film 24 to soften or deform, making it unable to effectively isolate burrs. The insulating layer 23 can provide heat insulation and thermal stability, and enhance the adhesion between the current collector 211 and the insulating film 24. In addition, when an electrolyte is present inside the battery cell, the electrolyte will gradually erode the interface between the current collector 211 and the insulating film 24, leading to connection failure. The insulating layer 23 has good stability and can resist the erosion of electrolytes and other chemical substances. Therefore, the insulating film 24 and the insulating layer 23 have a high interfacial bonding strength.

[0162] According to one embodiment of this application, such as Figure 5 and Figure 6 As shown, in the thickness direction z, the insulating film 24 does not overlap with the first active material layer 22.

[0163] In some examples, the insulating film 24 and the first active material layer 22 are spaced apart along a first direction x.

[0164] In these alternative embodiments, during the battery charging and discharging process, the expansion and contraction of the active material layer will cause compression or friction on the insulating film 24. Therefore, in the thickness direction z, the insulating film 24 does not overlap with the first active material layer 22, which improves the stability of the insulating film 24.

[0165] According to one embodiment of this application, such as Figure 5 and Figure 6 As shown, in the first direction x, the end of the insulating film 24 facing the first active material layer 22 is spaced apart from the first active material layer 22.

[0166] In some examples, in the first direction x, the end of the insulating film 24 facing the first active material layer 22 is spaced apart from the first active material layer 22, and the end of the insulating film 24 away from the first active material layer 22 protrudes from the end face of the current collector 211 facing the tab 212 and the end face of the insulating layer 23 away from the first active material layer 22.

[0167] In some examples, in the first direction x, the end of the insulating film 24 away from the first active material layer 22 protrudes from the end face of the current collector 211 facing the tab 212 and the end face of the insulating layer 23 away from the first active material layer 22, and the end of the insulating film 24 away from the first active material layer 22 does not protrude from the end face of the tab 212 away from the current collector 211.

[0168] In some examples, in the first direction x, the end of the insulating film 24 facing away from the first active material layer 22 overlaps with at least a portion of the tab 212 in the thickness direction z; or, the end of the insulating film 24 facing away from the first active material layer 22 does not overlap with the tab 212 in the thickness direction z.

[0169] In these alternative embodiments, the insulating film 24 and the first active material layer 22 are spaced apart. The spaced arrangement of the insulating film 24 and the first active material layer 22 can provide more flow channels for the liquid electrolyte, thereby reducing the obstruction of the insulating film 24 to the liquid electrolyte and allowing the liquid electrolyte to penetrate more evenly into all parts of the first active material layer 22.

[0170] According to one embodiment of this application, in the first direction x, the distance between the insulating film 24 and the first active material layer 22 is greater than or equal to 1 mm.

[0171] In some examples, in the first direction x, the insulating layer 23 is located on the side of the first active material layer 22 near the tab 212, and the insulating layer 23 is at least partially in contact with the first active material layer 22.

[0172] Optionally, the insulating film 24 is attached to the insulating layer 23. In the first direction x, the distance between the insulating film 24 and the first active material layer 22 is greater than or equal to 1 mm and smaller than the size of the insulating layer 23.

[0173] In these alternative embodiments, the insulating film 24 has a suitable spacing from the first active material layer 22 to reduce the amount of insulating film 24 used.

[0174] According to one embodiment of this application, such as Figure 5 and Figure 6 As shown, the current collecting body 211 has an insulating layer 23 on both sides along the thickness direction z, and an insulating film 24 is attached to the side of each insulating layer 23 away from the current collecting body 211.

[0175] In some examples, the current collector 211 has an insulating layer 23 on both sides along the thickness direction z, and an insulating film 24 is attached to the side of each insulating layer 23 away from the current collector 211. The two insulating films 24 at least partially overlap along the thickness direction z.

[0176] In some examples, the current collector 211 has an insulating layer 23 on both sides along the thickness direction z, and an insulating film 24 is attached to the side of each insulating layer 23 away from the current collector 211. The two insulating films 24 may have the same size along the first direction x, or the two insulating films 24 may have different sizes along the first direction x.

[0177] In these alternative embodiments, two insulators can separate the burrs on the end face of the current collector 211 from the isolation members 2c on both sides, thereby further reducing the risk of short circuit.

[0178] According to one embodiment of this application, such as Figure 4 and Figure 6 As shown, the portions of the two insulating films 24 that protrude from the end face of the current collector 211 facing the tab 212 are bonded together.

[0179] For example, the end face of the current collector 211 facing the tab 212 includes a tab 212 lead-out area and a non-tab 212 lead-out area, with the first tab 212 leading out only from the tab 212 lead-out area. The portions of the two insulating films 24 protruding from the end face of the current collector 211 facing the tab 212 are bonded together, and their projection along the first direction x covers at least a portion of the non-tab 212 lead-out area.

[0180] In some examples, the insulating film 24 includes a first part and a second part. The first part is attached to the insulating layer 23 and is located on the side of the insulating layer 23 away from the current collector 211. The second part is connected to the first part and protrudes from the end face of the current collector 211 facing the tab 212. The two insulating films 24 are at least partially disposed opposite each other along the thickness direction z. The second parts of the two insulating films 24 are both bonded. Alternatively, the second parts of the two insulating films 24 are only partially bonded.

[0181] In these alternative embodiments, the portions of the two insulating films 24 protruding from the end faces of the current collector 211 facing the tab 212 are bonded together, which can reduce the risk of the insulating films 24 falling off and can also cover at least part of the burrs on the end faces between the two insulating films 24.

[0182] According to one embodiment of this application, such as Figure 5 and Figure 6 As shown, the insulating film 24 includes a first insulating portion 241 and a second insulating portion 242 arranged along the first direction x. The first insulating portion 241 is attached to the insulating layer 23 and overlaps with the current collector 211 in the thickness direction z. The second insulating portion 242 is located on the side of the first insulating portion 241 near the tab 212.

[0183] For example, in the thickness direction z, the projection of the first insulating part 241 is located within the projection of the current collecting body 211, and the projection of the second insulating part 242 does not overlap with the projection of the current collecting body 211.

[0184] The first insulating part 241 and the second insulating part 242 may have the same shape or different shapes.

[0185] In some examples, the projection of the second insulating portion 242 overlaps with the projection of the tab 212 in the thickness direction z; or, the projection of the second insulating portion 242 does not overlap with the projection of the tab 212.

[0186] For example, the end of the second insulating portion 242 away from the first insulating portion 241 protrudes from the end face of the current collector 211 facing the tab 212 and the end face of the insulating layer 23 facing away from the first active material layer 22.

[0187] Optionally, in the thickness direction z, a portion of the projection of the second insulating portion 242 does not overlap with the projection of the tab 212.

[0188] In these alternative embodiments, the first insulating portion 241 can have a large connection area with the insulating layer 23, reducing the risk of the insulating film 24 detaching. The second insulating portion 242 can separate the burrs of the current collector 211 from the isolator 2c, thereby reducing the risk of short circuit.

[0189] According to one embodiment of this application, such as Figure 5 As shown, a portion of the second insulating part 242 overlaps with the tab 212 along the thickness direction z.

[0190] In some examples, the tab 212 protrudes from the second insulating portion 242 in the direction from the current collector 211 to the tab 212. This facilitates connection with other conductive structures and reduces the risk of interference between the second insulating portion 242 and the conductive structures.

[0191] For example, a portion of the second insulating portion 242 overlaps with the tab 212 along the thickness direction z, and a portion of the second insulating portion 242 is close to the root of the tab 212, while another portion of the second insulating portion 242 does not overlap with the tab 212 along the thickness direction z.

[0192] In these alternative embodiments, the second insulating portion 242 can support the tab 212, reducing the risk that the tab 212 may be inserted upside down between the first electrode 2a and the second electrode 2b when bent, thereby reducing the risk of short circuit and improving reliability.

[0193] See also Figure 7 and Figure 8 , Figure 7 This is a schematic diagram of the first electrode sheet without an insulating film in a flattened state according to an embodiment of this application; Figure 8 This is a schematic diagram of the first electrode sheet provided in an embodiment of this application in a flattened state.

[0194] According to one embodiment of this application, such as Figure 5 , Figure 7 and Figure 8 As shown, the second insulating portion 242 includes a first sub-portion 2421 and a second sub-portion 2422 arranged along a second direction y. The first sub-portion 2421 overlaps with the tab 212 along the thickness direction z. The second direction y is perpendicular to the first direction x and the thickness direction z. The second sub-portion 2422 is connected to the first sub-portion 2421 and the first insulating portion 241.

[0195] The second insulating portion 242 includes a first sub-portion 2421 and a second sub-portion 2422 arranged along the second direction y. The first sub-portion 2421 overlaps only with the tab 212 along the thickness direction z, while the second sub-portion 2422 does not overlap with the tab 212 along the thickness direction z.

[0196] Optionally, in the first direction x, the first sub-part 2421 and the second sub-part 2422 are flush.

[0197] In some examples, the second insulating portion 242 includes a plurality of first sub-portions 2421 and a plurality of second sub-portions 2422, which are arranged alternately along a second direction y. Before the first electrode 2a is wound, the flattened first electrode 2a includes a plurality of sub-electrode tabs, which are connected after winding to form electrode tabs 212. The insulating film 24 includes a plurality of first sub-portions 2421 that are correspondingly arranged with the plurality of sub-electrode tabs.

[0198] In these alternative embodiments, the second insulating portion 242 may shield some of the burrs formed during the molding process of the tab 212, thereby reducing the risk of short circuit.

[0199] According to one embodiment of this application, the second sub-parts 2422 of two insulating films 24 opposite each other along the thickness direction z are connected.

[0200] For example, the current collector 211 has an insulating layer 23 on both sides along the thickness direction z, and an insulating film 24 is attached to the side of each insulating layer 23 away from the current collector 211. The second sub-parts 2422 of the two insulating films 24 are bonded to the end faces of the tabs 212.

[0201] According to one embodiment of this application, such as Figure 7 and Figure 8 As shown, the insulating layer 23 includes a first region 231 and a second region 232. The first region 231 is disposed on the current collector 211, and the second region 232 is connected to the first region 231. The second region 232 is disposed on the tab 212, which protrudes from the insulating layer 23 along the first direction x. A first insulating portion 241 is attached to the first region 231, and a second insulating portion 242 is attached to the second region 232.

[0202] The first region 231 and the second region 232 are arranged along the direction from the current collection body 211 to the electrode 212, and the second region 232 is located on the electrode 212. The electrode 212 has a second region on one side along the thickness direction z, or the electrode 212 has a second region on both sides along the thickness direction z.

[0203] In some examples, along the first direction x, tab 212 protrudes from insulating layer 23, and insulating layer 23 protrudes from insulating film 24.

[0204] Optionally, the second region 232 is disposed on the tab 212 and located at the root of the tab 212.

[0205] Exemplarily, the insulating layer 23 includes a first region 231 and a second region 232. The first region 231 is disposed on the current collector 211, and the second region 232 is connected to the first region 231 and disposed on the tab 212. Along the first direction x, the tab 212 protrudes from the insulating layer 23. The insulating film 24 includes a first insulating portion 241 and a second insulating portion 242 arranged along the first direction x.

[0206] The second insulating portion 242 includes a first sub-portion 2421 and a second sub-portion 2422 arranged along the second direction y. The first sub-portion 2421 is attached to the first region 231, and the second sub-portion 2422 is connected to the first sub-portion 2421 and the first insulating portion 241. The first insulating portion 241 is attached to the first region 231.

[0207] In these alternative embodiments, the second region 232 of the insulating layer 23 can provide effective support for the tab 212, reducing the risk of the first tab 212 being inserted upside down between the first electrode 2a and the second electrode 2b. The insulating layer 23 can have a certain insulating effect, which can effectively limit the deformation of the tab 212.

[0208] According to one embodiment of this application, such as Figure 7 and Figure 8 As shown, in the first direction x, the size m of the second insulating part 242 and the size n of the second region 232 satisfy: 0mm≤nm≤2mm.

[0209] In some examples of this application, in the first direction x, the size m of the second insulating portion 242 and the size n of the second region 232 satisfy nm as 0 mm, 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 other ranges formed by any two of the above endpoints.

[0210] In these alternative embodiments, the use of insulating film 24 is reduced, and the internal space of the battery cell is made more efficient to improve the energy density of the battery cell.

[0211] According to one embodiment of this application, such as Figure 7 and Figure 8 As shown, in the first direction x, the size n of the second region 232 is 1 mm to 20 mm.

[0212] In some examples of this application, the size n of the second region 232 in the first direction x is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or other ranges formed by any two of the above endpoints.

[0213] Optionally, the size n of the second region 232 is 1 mm to 5 mm.

[0214] In these alternative embodiments, the insulating layer 23 has a suitable size on the tab 212, and the use of the insulating layer 23 is appropriately reduced while still supporting the tab 212, thereby improving the energy density of the battery cell.

[0215] According to one embodiment of this application, the misalignment of the two insulating films 24 in the first direction x is less than or equal to 0.6 mm.

[0216] In these alternative embodiments, the two insulating films 24 in the first direction x are arranged such that...

[0217] The overlapping areas can maintain stable insulation performance.

[0218] According to one embodiment of this application, such as Figure 7 and Figure 8 As shown, in the first direction x, the dimension m of the insulating film 24 protruding from the end face of the current collector 211 facing the tab 212 satisfies: 0.5mm≤c≤2mm.

[0219] In some examples, the insulating film 24 includes a first insulating portion 241 and a second insulating portion 242 arranged along a first direction x. The first insulating portion 241 is attached to the insulating layer 23 and overlaps with the current collector 211 along the thickness direction z. In the first direction x, the second insulating portion 242 protrudes from the end face of the current collector 211 facing the tab 212. The dimension m of the second insulating portion 242 satisfies: 0.5mm≤c≤2mm.

[0220] In some examples of this application, in the first direction x, the dimension m of the insulating film 24 protruding from the end face of the current collector 211 facing the tab 212 is 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 in other ranges consisting of any two of the above endpoints.

[0221] Optionally, in the first direction x, the dimension m of the insulating film 24 protruding from the end face of the current collector 211 facing the tab 212 satisfies: 1mm≤c≤1.5mm.

[0222] In these alternative embodiments, this arrangement can reduce the use of the insulating film 24 and also reduce the interference of the insulating film 24 with the tab 212.

[0223] According to one embodiment of this application, the thickness of the insulating film 24 is 9 μm to 30 μm.

[0224] In some examples of this application, the thickness of the insulating film 24 is 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, or other ranges formed by any two of the above endpoints.

[0225] In these alternative embodiments, limiting the thickness of the insulating layer 23 to greater than or equal to 7 μm can reduce the risk of the insulating layer 23 being punctured by burrs and improve reliability. Limiting the thickness of the insulating layer 23 to less than or equal to 30 μm can reduce the space and weight occupied by the insulating layer 23 and reduce the energy density loss of the battery cell.

[0226] According to one embodiment of this application, in the first direction x, the size of the insulating layer 23 on the current collector 211 is 2 mm to 4 mm.

[0227] At least a portion of the insulating layer 23 is disposed on the current collecting body 211, and the insulating layer 23 on the current collecting body 211 is the portion of the insulating layer 23 that overlaps with the current collecting body 211 along the thickness direction z.

[0228] In some examples of this application, in the first direction x, the size of the insulating layer 23 on the current collector 211 is 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4.0 mm, or other ranges formed by any two of the above endpoints.

[0229] In these alternative embodiments, limiting the size of the insulating layer 23 on the current collector 211 to greater than or equal to 2 mm can improve insulation performance. Limiting the size of the insulating layer 23 on the current collector 211 to less than or equal to 4 mm can reduce the space and weight occupied by the insulating layer 23, thereby increasing the proportion of the first active material layer 22 on the current collector 211, thereby increasing the energy density of the battery cell.

[0230] According to one embodiment of this application, the insulating layer 23 comprises ceramic.

[0231] According to one embodiment of this application, the first electrode 2a is a positive electrode, and the second electrode 2b is a negative electrode.

[0232] In some embodiments, the insulating film 24 includes a substrate layer and an adhesive layer disposed on the surface of the substrate layer. The substrate layer is made of at least one of polyethylene terephthalate, polypropylene, polyethylene, and their block copolymers. The adhesive layer is made of at least one of polyolefin, polyester, and styrene-isobutylene copolymer. The adhesive layer has high adhesive strength, making the insulating film 24 less likely to detach from the insulating layer 23.

[0233] In some embodiments, the insulating layer 23 is one of white, gray, and light yellow.

[0234] In some embodiments, the insulating film 24 is one of white, gray, and pale yellow.

[0235] In some embodiments, the light transmittance of the insulating film 24 is 55% ≤ f ≤ 75%, and the haze is 50% ≤ h ≤ 70%. On the one hand, this reduces the obstruction of the tab 212, and on the other hand, it facilitates differentiation from the tab 212.

[0236] In some embodiments, the battery cell includes a liquid electrolyte contained within the housing 1. The insulating film 24 remains stable in the liquid electrolyte.

[0237] For example, after immersion in liquid electrolyte for 1000 hours, the peel strength between insulating film 24 and insulating layer 23 is greater than or equal to 2 N / m.

[0238] Optionally, after immersion in liquid electrolyte for 1000 hours, the peel strength between insulating film 24 and insulating layer 23 is 15 N / m-20 N / m.

[0239] In some embodiments, the insulating film 24 has good insulation properties, will not break down under a voltage of 200V, and has a resistance greater than or equal to 9999 megohms.

[0240] In some embodiments, the puncture strength of the insulating film 24 is greater than or equal to 300 gf.

[0241] Optionally, the puncture strength of the insulating film 24 is greater than or equal to 400 gf.

[0242] As an example, the puncture strength of the insulating film 24 can be measured as follows:

[0243] A section of insulating film 24 was cut off to prepare a sheet sample;

[0244] Fix the sample to the test fixture;

[0245] Using a puncture tester with a 1mm diameter needle, puncture at a speed of 50mm / min, and measuring the puncture force F after the data stabilizes, the puncture intensity (in units f) is calculated as F / 9.8*1000.

[0246] The test results showed that the puncture strength (in gf) of the insulating film 24 in 10 parallel samples were 416.33, 414.29, 428.57, 423.47, 420.41, 430.61, 414.29, 433.67, 426.53, and 444.90, respectively, with an average value of 425.31.

[0247] In these alternative embodiments, the risk of the insulating film 24 being punctured by burrs can be reduced, thereby reducing the risk of the burrs becoming conductive with the second electrode 2b, reducing the possibility of thermal runaway caused by short circuits, and improving the reliability of the battery cell.

[0248] In some embodiments, the puncture strength of the insulating film 24 is greater than the puncture strength of the separator 2c.

[0249] As an example, the peel strength of the insulating film 24 can be measured as follows:

[0250] A section of insulating film 24 is cut and fixed onto insulating layer 23 to prepare a sample;

[0251] After soaking in a liquid electrolyte at 70℃ for 200h, 400h, 600h, 800h, and 1000h respectively, the peel strength was tested. The peel strength can be tested according to GB / T 2792-2014 Test Method for Peel Strength of Adhesive Tapes.

[0252] The test results showed that after soaking for 200 hours, the peel strength was greater than 112 N / m; after soaking for 400 hours, the peel strength was greater than 29 N / m; after soaking for 600 hours, the peel strength was greater than 19 N / m; after soaking for 800 hours, the peel strength was greater than 19 N / m; and after soaking for 1000 hours, the peel strength was greater than 19 N / m.

[0253] In these alternative embodiments, the insulating film 24 has a high peel strength from the insulating layer 23, thereby reducing the risk of the insulating film 24 falling off and improving reliability.

[0254] In some embodiments, the insulating film 24 is configured to not undergo redox reactions within a voltage range of 2.5V-4.5V. The insulating film 24 is less prone to oxidation failure within this voltage environment, thereby reducing the risk of the insulating film 24 detaching and improving reliability.

[0255] As an example, the electrochemical stability of insulating film 24 can be tested as follows:

[0256] Part of the insulating film 24 is peeled off from the first electrode 2a;

[0257] Conductive carbon black and colloid are mixed at a mass ratio of 7:3, and then N-methylpyrrolidone solvent is added to disperse them evenly to obtain a slurry. The solid content of the slurry is controlled at 7%-10%.

[0258] The slurry is coated onto aluminum foil and dried to obtain an electrode sheet.

[0259] The prepared electrodes were fabricated into coin cells for cyclic voltammetry testing.

[0260] The test conditions were as follows: scan for 3 cycles at a scan speed of 0.1 mV / s, observe whether redox peaks appear within the voltage range of 2.5V-5V, plot the current-voltage curve, and record the voltage at which the first oxidation peak appears. The voltage at which the first oxidation peak appears can be taken as the voltage at which the redox reaction begins in the colloid.

[0261] The test results showed that the oxidation voltages of the five parallel samples were 4.6V, 4.7V, 4.5V, 4.6V, and 4.7V, respectively.

[0262] In some embodiments, the first electrode 2a is a positive electrode, and the first active material layer 22 includes a positive electrode active material, which includes lithium nickel cobalt manganese oxide. Lithium nickel cobalt manganese oxide has the advantage of high operating voltage.

[0263] The insulating film 24 of this embodiment is not easily oxidized and degraded at higher operating voltages, thereby reducing the risk of the insulating film 24 falling off and improving reliability.

[0264] Secondly, this application provides a battery device including the aforementioned battery cell.

[0265] Thirdly, this application provides an electrical device, including a battery cell or a battery device as described above, wherein the battery cell or battery device is used to store or provide electrical energy.

[0266] According to some embodiments of this application, see Figures 3 to 5 , Figure 7 and Figure 8 As shown, this application provides a battery cell, which includes a housing 1 and an electrode assembly 2.

[0267] The outer casing 1 has a receiving cavity 11.

[0268] Electrode assembly 2 is disposed within receiving cavity 11. Electrode assembly 2 includes a first electrode 2a, a second electrode 2b, and a separator 2c. The first electrode 2a and the second electrode 2b have opposite polarities. The separator 2c is used to isolate the first electrode 2a and the second electrode 2b. The first electrode 2a is a positive electrode. The second electrode 2b is a negative electrode.

[0269] The first electrode 2a includes a first current collector 21, a first active material layer 22, an insulating layer 23, and an insulating film 24.

[0270] The first current collector 21 includes a current collector body 211 and an electrode 212 disposed along a first direction x, and a first active material layer 22 disposed on the current collector body 211. The first direction x is perpendicular to the thickness direction z.

[0271] At least a portion of the insulating layer 23 is disposed on the current collector 211 and located on the side of the first active material layer 22 near the tab 212. The current collector 211 has insulating layers 23 on both sides along the thickness direction z. An insulating film 24 is attached to the side of each insulating layer 23 facing away from the current collector 211. The insulating layer 23 includes a first region 231 and a second region 232. The first region 231 is disposed on the current collector 211, and the second region 232 is connected to the first region 231 and disposed on the tab 212. Along the first direction x, the tab 212 protrudes from the insulating layer 23. In the first direction x, the size of the first region 231 is 2 mm to 4 mm. The size n of the second region 232 is 1 mm to 20 mm. The insulating layer 23 comprises ceramic.

[0272] In the first direction x, the end of the insulating film 24 facing the first active material layer 22 is spaced apart from the first active material layer 22, with a spacing greater than or equal to 1 mm. In the first direction x, the dimension m of the insulating film 24 protruding from the end face of the current collector 211 facing the tab 212 satisfies: 0.5 mm ≤ c ≤ 2 mm. The insulating film 24 includes a first insulating portion 241 and a second insulating portion 242 arranged along the first direction x. The first insulating portion 241 is attached to the first region 231 and overlaps with the current collector 211 in the thickness direction z. The second insulating portion 242 is located on the side of the first insulating portion 241 near the tab 212. The second insulating portion 242 protrudes from the end face of the current collector 211 facing the tab 212 and is attached to the second region 232. The second insulating portion 242 includes a first sub-portion 2421 and a second sub-portion 2422 arranged along a second direction y. The first sub-portion 2421 overlaps with the tab 212 along the thickness direction z. The second direction y is perpendicular to the first direction x and the thickness direction z. The second sub-portion 2422 is connected to the first sub-portion 2421 and the first insulating portion 241. The second sub-portions 2422 of the two insulating films 24 opposite each other along the thickness direction z are bonded together. In the first direction x, the dimension m of the second insulating portion 242 and the dimension n of the second region 232 satisfy: 0 mm ≤ nm ≤ 2 mm. The thickness of the insulating film 24 is 9 μm to 30 μm.

[0273] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer shell has a receiving cavity; An electrode assembly is disposed within the receiving cavity. The electrode assembly includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities, and the separator is used to isolate the first electrode and the second electrode. The first electrode includes a first current collector, a first active material layer, an insulating layer, and an insulating film. The first current collector includes a current collector body and a tab disposed along a first direction. The first active material layer is disposed on the current collector body. At least a portion of the insulating layer is disposed on the current collector body and located on the side of the first active material layer near the tab. In the thickness direction of the current collector body, at least a portion of the insulating film is located on the side of the insulating layer opposite to the current collector body and is attached to the insulating layer. The first direction is perpendicular to the thickness direction. Along the direction from the current collector to the tab, the insulating film protrudes from the end face of the current collector facing the tab and the end face of the insulating layer facing away from the first active material layer.

2. The battery cell according to claim 1, characterized in that, In the thickness direction, the insulating film does not overlap with the first active material layer.

3. The battery cell according to claim 2, characterized in that, In the first direction, the end of the insulating film facing the first active material layer is spaced apart from the first active material layer.

4. The battery cell according to claim 3, characterized in that, In the first direction, the distance between the insulating film and the first active material layer is greater than or equal to 1 mm.

5. The battery cell according to claim 1, characterized in that, The current collecting body has insulating layers on both sides along the thickness direction, and each insulating layer has an insulating film attached to the side facing away from the current collecting body.

6. The battery cell according to claim 5, characterized in that, The portions of the two insulating films that protrude from the end face of the current collector body facing the tab are bonded together.

7. The battery cell according to claim 1, characterized in that, The insulating film includes a first insulating portion and a second insulating portion arranged along the first direction. The first insulating portion is attached to the insulating layer and overlaps with the current collector in the thickness direction. The second insulating portion is located on the side of the first insulating portion near the tab.

8. The battery cell according to claim 7, characterized in that, A portion of the second insulating portion overlaps with the tab along the thickness direction.

9. The battery cell according to claim 7, characterized in that, The second insulating portion includes a first sub-portion and a second sub-portion arranged along a second direction, the first sub-portion overlapping the electrode tab along the thickness direction, and the second direction being perpendicular to the first direction and the thickness direction; The second sub-part is connected to the first sub-part and the first insulating part.

10. The battery cell according to claim 9, characterized in that, The second sub-sections of the two insulating films that are opposite each other along the thickness direction are connected.

11. The battery cell according to claim 8, characterized in that, The insulating layer includes a first region and a second region. The first region is disposed on the current collecting body, and the second region is connected to the first region. The second region is disposed on the electrode tab, and the electrode tab protrudes from the insulating layer along the first direction. The first insulating portion is attached to the first region, and the second insulating portion is attached to the second region.

12. The battery cell according to claim 11, characterized in that, In the first direction, the size m of the second insulating part and the size n of the second region satisfy: 0mm≤nm≤2mm.

13. The battery cell according to claim 11, characterized in that, In the first direction, the size n of the second region is from 1 mm to 20 mm.

14. The battery cell according to claim 5, characterized in that, The misalignment of the two insulating films in the first direction is less than or equal to 0.6 mm.

15. The battery cell according to claim 1, characterized in that, In the first direction, the dimension m of the insulating film protruding from the end face of the current collector body facing the tab satisfies: 0.5mm≤c≤2mm.

16. The battery cell according to claim 1, characterized in that, The thickness of the insulating film is 9 μm to 30 μm.

17. The battery cell according to claim 1, characterized in that, In the first direction, the size of the insulating layer on the current collector body is 2 mm to 4 mm.

18. The battery cell according to claim 1, characterized in that, The insulating layer comprises ceramic.

19. The battery cell according to claim 1, characterized in that, The first electrode is a positive electrode.

20. A battery device, characterized in that, It includes multiple battery cells according to any one of claims 1 to 19.

21. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1 to 19 or a battery device according to claim 20, wherein the battery cell or the battery device is used to store or provide electrical energy.

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