Battery cell, battery, and electric device

Abstract

The present application provides a battery cell, a battery, and an electric device. The battery cell comprises an electrode assembly, a housing, and an insulating film; the electrode assembly is accommodated in the housing, and the insulating film is arranged on the outer surface of the housing. Because the outer surface of the housing of the battery cell is provided with an insulating film having insulating properties, the battery cell has good insulation capability and is not prone to short-circuiting with adjacent battery cells, helping to improve the reliability of the battery.

Description

Battery cells, batteries and electrical devices Technical Field

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

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

[0003] As the frequency of battery use in people's lives continues to increase, how to improve the reliability of batteries has attracted more and more attention from those skilled in the art.

[0004] Summary of the Invention

[0005] In view of the above problems, the present application provides a battery cell, a battery and an electrical device. The battery cell has good insulation ability, which is conducive to improving the reliability of the battery.

[0006] In a first aspect, some embodiments of the present application provide a battery cell, which includes an electrode assembly, a housing, and an insulating film, wherein the electrode assembly is accommodated in the housing, and the insulating film is disposed on an outer surface of the housing.

[0007] In the above structure, since the outer surface of the battery cell housing is provided with an insulating film with insulating properties, the battery cell has good insulation capability and is not prone to short circuit with adjacent battery cells, which is beneficial to improving the reliability of the battery.

[0008] According to the battery cells provided in some embodiments of the present application, the melting point of the insulating film is T, T≥250°C, so that the insulating film is not easy to melt even in a high temperature environment and can maintain its original structural state, so that the outer shell of the battery cell is not easy to be exposed, reducing the possibility of direct contact between the outer shells of two adjacent battery cells, so that the battery cell has good insulation ability even at high temperatures, is not easy to short-circuit with adjacent battery cells, and is conducive to improving the reliability of the battery.

[0009] According to the battery cells provided in some embodiments of the present application, the dielectric strength of the insulating film is P, P≥10kV / mm, so that the insulating film has good insulation performance and is not easily broken down. Under the isolation effect of the insulating film, short circuit is not likely to occur between two adjacent battery cells, which is beneficial to the reliability of the battery.

[0010] According to some embodiments of the present application, the battery cell includes a first film layer and a second film layer stacked together. The first film layer is disposed on the outer surface of the housing, and the second film layer is disposed on a side of the first film layer away from the housing. By stacking the first and second film layers, the insulating film comprises at least two structural layers, resulting in a composite film structure. This facilitates adjustment of performance parameters of different film structures to better meet various requirements.

[0011] In the battery cells provided in some embodiments of the present application, the hardness of the second film layer is higher than that of the first film layer. Because the second film layer is disposed on the outer side of the first film layer, away from the outer shell, and by configuring the second film layer to have a higher hardness than the first film layer, the structural layer of the insulating film away from the outer shell has a higher hardness, which can better protect the internal structural layer of the insulating film. This not only helps improve the wear resistance of the insulating film, but also helps reduce the possibility of damage to the insulating film due to bumps and scratches, thereby helping to extend the service life of the insulating film.

[0012] According to the battery cells provided in some embodiments of the present application, the melting point of the first film layer is T1, and the melting point of the second film layer is T2, where T1>T2. Because the first film layer is disposed on the outer surface of the housing, and the second film layer is disposed on the side of the first film layer away from the housing, the first film layer, which is closer to the battery cell housing, heats up faster and reaches a higher temperature. By configuring the melting point T1 of the first film layer to be higher than the melting point T2 of the second film layer, the first film layer has better high-temperature resistance, making it less likely to melt due to excessive temperatures, thereby improving the high-temperature resistance of the insulating film.

[0013] According to the battery cell provided in some embodiments of the present application, the dielectric strength of the first film layer is D1, D1 ≥ 10 kV / mm, so that the first film layer can increase the dielectric strength of the insulating film and improve the insulating performance of the insulating film.

[0014] In the battery cells provided in some embodiments of the present application, the surface oxidation index of the second film layer is lower than that of the first film layer. Because the second film layer is disposed on the outside of the first film layer, away from the outer shell, and by setting the surface oxidation index of the second film layer lower than that of the first film layer, the second film layer, located outside the insulating film, has stronger oxidation resistance. This improves the oxidation resistance of the outer surface of the insulating film in contact with air, thereby extending the service life of the insulating film.

[0015] In the battery cells provided in some embodiments of the present application, the thickness of the first film layer is greater than the thickness of the second film layer. Because the first film layer is disposed inside the second film layer and the melting point T1 of the first film layer is higher than the melting point T2 of the second film layer, by setting the thickness of the first film layer to be greater than the thickness of the second film layer, the thickness of the structural layer with the higher melting point is greater than that of the structural layer with the lower melting point, thereby enhancing the high-temperature resistance of the insulating film, which is beneficial to improving the high-temperature resistance of the insulating film.

[0016] According to the battery cells provided in some embodiments of the present application, the ratio of the thickness of the second film layer to the thickness of the first film layer is R, 0.25≤R≤0.5, so that the first film layer can occupy a larger part in the insulating film, which helps to further improve the high temperature resistance of the insulating film.

[0017] In the battery cells provided in some embodiments of the present application, the first film layer is a polyimide film layer, and the second film layer is a polyethylene terephthalate film layer. Because polyimide has a higher melting point and a higher surface oxidation index than polyethylene terephthalate, configuring the first film layer as a polyimide film layer and the second film layer as a polyethylene terephthalate film layer not only effectively improves the oxidation resistance of the outer surface of the insulating film, but also helps improve the insulating film's high-temperature resistance.

[0018] According to the battery cell provided in some embodiments of the present application, the thickness of the first film layer is L1, 20μm≤L1≤180μm; and / or the thickness of the second film layer is L2, 20μm≤L2≤120μm, so that the first film layer and the second film layer have good manufacturability and low cost.

[0019] According to the battery cell provided in some embodiments of the present application, the insulating film further includes a first adhesive layer and a second adhesive layer, the first adhesive layer is bonded between the second film layer and the first film layer, and the second adhesive layer is bonded between the first film layer and the outer shell.

[0020] According to the battery cells provided in some embodiments of the present application, the bonding strength of the first adhesive layer is greater than the bonding strength of the second adhesive layer, so that the peeling strength between the second film layer and the first film layer is greater than the peeling strength between the first film layer and the outer shell, and the bonding force between the second film layer and the first film layer is greater than the bonding force between the first film layer and the outer shell, so that in the process of peeling the insulating film from the outer shell, the first adhesive layer and the second adhesive layer are not easy to separate, making it easy to peel the insulating film from the outer shell.

[0021] According to the battery cells provided in some embodiments of the present application, the interlayer peeling strength between the second adhesive layer and the first film layer is A, and the interlayer peeling strength between the second adhesive layer and the outer shell is B, A>B, so that the adhesion force between the second adhesive layer and the first film layer is greater than the adhesion force between the second adhesive layer and the outer shell, so that in the process of peeling the insulating film from the outer shell, the second adhesive layer is not easily separated from the first film layer, so that the second adhesive layer can be easily peeled from the outer shell, which facilitates the cleaning of the second adhesive layer.

[0022] According to the battery cells provided in some embodiments of the present application, the interlayer peeling strength between the first adhesive layer and the second film layer is C, the interlayer peeling strength between the first adhesive layer and the first film layer is D, the interlayer peeling strength between the second adhesive layer and the first film layer is A, and the interlayer peeling strength between the second adhesive layer and the outer shell is B, A≥300N / m, B≥300N / m, C≥300N / m, D≥300N / m, so that the first adhesive layer and the second adhesive layer are firmly bonded, and the first adhesive layer is firmly bonded to the outer shell, which not only makes it difficult for the insulating film to fall off from the outer shell, but also makes it difficult for the insulating film to be delaminated, which is beneficial to improving the structural integrity of the insulating film and facilitates the insulating film to be completely peeled off from the outer shell by tearing or the like.

[0023] According to the battery cells provided in some embodiments of the present application, A ≥ 350 N / m, B ≥ 350 N / m, C ≥ 350 N / m, and D ≥ 350 N / m, the firmness of the bonding between the first adhesive layer and the second adhesive layer, and the firmness of the bonding between the first adhesive layer and the outer shell can be further improved, so that the insulating film is not easy to fall off from the outer shell and is not easy to delaminate, which facilitates the insulating film to be completely peeled off from the outer shell.

[0024] According to the battery cell provided in some embodiments of the present application, the second adhesive layer includes a pressure-sensitive adhesive, which enables the insulating film to be peeled off from the outer shell relatively easily without contaminating the outer shell, so that the insulating film of the battery cell can be conveniently replaced.

[0025] In a second aspect, some embodiments of the present application provide a battery comprising a battery cell provided by any of the above technical solutions.

[0026] Since the battery includes the battery cells provided by the above technical solution, short circuits are unlikely to occur between adjacent battery cells in the battery, so that the battery cells have good reliability.

[0027] According to some embodiments of the present application, the battery further includes an isolating member. A plurality of battery cells are provided, and the plurality of battery cells are stacked along a first direction. An isolating member is sandwiched between the outer shells of two adjacent battery cells to space the two adjacent battery cells apart.

[0028] By sandwiching an isolating member between the shells of two battery cells, two adjacent battery cells can be spaced apart, which is beneficial to improving the insulation performance between the two adjacent battery cells and further reducing the possibility of short circuit between the two adjacent battery cells.

[0029] According to the battery provided in some embodiments of the present application, the separator includes microporous foamed polypropylene, so that the separator has good insulation, high temperature resistance and buffering capacity.

[0030] According to the battery provided in some embodiments of the present application, the isolation member includes a frame and an opening surrounded by the frame, the frame is supported by the insulating film of the battery cell, and the opening is located between two adjacent battery cells to form an isolation cavity.

[0031] Since the frame is clamped between the insulating films of two adjacent battery cells, the isolation member not only increases the distance between the two adjacent battery cells, but the isolation cavity therein can also form an air layer between the insulating films of the two adjacent battery cells, which is beneficial to improving the insulation performance between the two adjacent battery cells, further reducing the possibility of short circuit between adjacent battery cells, and helping to improve the reliability of the battery.

[0032] According to some embodiments of the present application, the battery is provided with multiple openings. By distributing the openings in the separator into multiple pieces, a frame is provided between adjacent openings. The frame can enhance the structural strength of the separator and help reduce the possibility of damage to the separator.

[0033] According to some embodiments of the present application, the electrical device includes a battery provided by any of the above technical solutions, and the battery is used to provide electrical energy.

[0034] The technical solutions provided by the embodiments of the present disclosure bring at least the following beneficial effects:

[0035] The present application provides a battery cell comprising an electrode assembly, a housing, and an insulating film. The electrode assembly is housed in the housing, and the insulating film is disposed on the outer surface of the housing. Because the outer surface of the housing of the battery cell is provided with an insulating film having insulating properties, the battery cell has excellent insulation capabilities and is less likely to short-circuit with adjacent battery cells, thereby improving battery reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. Throughout the accompanying drawings, the same reference numerals are used to denote the same components.

[0037] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0038] FIG2 is a schematic diagram of the disassembled structure of a battery provided in some embodiments of the present application;

[0039] FIG3 is a schematic diagram of the disassembled structure of a battery cell provided in some embodiments of the present application;

[0040] FIG4 is a cross-sectional view of an insulating film in a battery cell provided by some embodiments of the present application;

[0041] FIG5 is a cross-sectional view of an isolation member in a battery provided by some embodiments of the present application;

[0042] FIG6 is a schematic structural diagram of a separator in a battery provided in some embodiments of the present application;

[0043] FIG7 is an enlarged view of point E in FIG5 ;

[0044] FIG8 is a schematic structural diagram of an isolating element in a battery provided in some other embodiments of the present application.

[0045] In the figure: 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a. First box part; 5b. Second box part; 5c. Accommodation space; 7. Battery cell; 20. Outer shell; 201. Shell; 202. Cover; 30. Electrode assembly; 40. Insulating film; 401. First film layer; 402. Second film layer; 403. First adhesive layer; 404. Second adhesive layer; 50. Isolator; 501. Frame; 502. Opening. DETAILED DESCRIPTION

[0046] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0047] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should have the common meanings understood by technicians in the field to which the embodiments of the present application belong.

[0048] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0049] In addition, the technical terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly indicate the number of the technical features indicated. In the description of the embodiments of this application, the meaning of "plurality" is two or more, unless otherwise specifically defined.

[0050] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0051] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0052] Currently, market developments indicate that batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, so too are people's demands for batteries.

[0053] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0054] The battery cell may be a secondary battery cell, which refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0055] The battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0056] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include square-shell, blade-shaped, and polygonal batteries. Polygonal batteries may be, for example, hexagonal batteries.

[0057] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0058] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0059] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0060] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0061] To meet requirements for output voltage, power, and other factors, batteries typically contain a large number of cells. To fully utilize the battery's internal space, these cells are often placed closely together. This creates the risk of overlapping casings of adjacent cells, making short circuits between them more likely.

[0062] To improve the insulation capability of battery cells and enhance battery reliability, some embodiments of the present application provide a battery cell comprising an electrode assembly, a housing, and an insulating film. The electrode assembly is housed within the housing, and the insulating film is disposed on the outer surface of the housing. Because the outer surface of the housing of the battery cell is provided with an insulating film having insulating properties, the battery cell has excellent insulation capability and is less likely to short-circuit with adjacent battery cells, thereby improving battery reliability.

[0063] The battery cells described in the embodiments of the present application are suitable for use in batteries and electrical devices using the batteries.

[0064] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be fuel-powered, gas-powered, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. 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.

[0065] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0066] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0067] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may serve as an operating power source for the vehicle 1.

[0068] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0069] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0070] Figure 2 is a schematic diagram of the disassembled structure of a battery provided in some embodiments of the present application. As shown in Figure 2, the battery 2 includes a housing 5 and a battery cell 7, which is accommodated in the housing 5. The battery cell 7 can be the smallest unit of the battery.

[0071] The housing 5 is used to accommodate the battery cells 7 and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other and together define a storage space 5c for accommodating the battery cells 7. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also both be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0072] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0073] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0074] In the battery 2, there can be one or more battery cells 7. If there are multiple battery cells 7, the multiple battery cells 7 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections within the multiple battery cells 7. The multiple battery cells 7 can be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 7 can be housed within the housing 5. Alternatively, multiple battery cells 7 can be first connected in series, in parallel, or in a hybrid connection to form a battery module 6, and then the multiple battery modules 6 can be connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 5.

[0075] The battery cell 7 may be a cylindrical battery cell, a square battery cell, or a battery cell of other shapes.

[0076] As shown in FIG3 , in some embodiments, the battery cell 7 includes a housing 20 and an electrode assembly 30 . The electrode assembly 30 is housed in the housing 20 .

[0077] The housing 20 can have various shapes and sizes, such as a rectangular parallelepiped or a hexagonal prism. Specifically, the shape of the housing 20 can be determined based on the specific shape and size of the electrode assembly 30. The housing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, and aluminum alloy, and the present embodiment does not impose any particular limitations thereon.

[0078] The electrode assembly 30 is a component where electrochemical reactions occur in the battery cell 7. One or more electrode assemblies 30 may be contained in the housing 20.

[0079] Some embodiments of the present application provide a battery cell 7 , as shown in FIG3 , which includes an electrode assembly 30 , a housing 20 , and an insulating film 40 . The electrode assembly 30 is housed in the housing 20 , and the insulating film 40 is disposed on the outer surface of the housing 20 .

[0080] The outer shell 20 is a component used to enclose a sealed space in the battery cell 7, which may include a shell 201 and a cover 202. The shell 201 is a hollow structure with an opening, and the cover 202 covers an opening of the shell 201 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 30 and the electrolyte.

[0081] The electrode assembly 30 is housed in the hollow structure enclosed by the housing 20 and includes electrode sheets and separators 50. The electrode sheets may include positive or negative electrode sheets of opposite polarity. The positive and negative electrode sheets may serve as the positive and negative electrodes, respectively. During the charge and discharge process of the battery cell 7, active ions (e.g., lithium ions) are intercalated and released between the positive and negative electrodes. The separators 50 are stacked between the positive and negative electrode sheets to isolate the positive and negative electrode sheets, preventing short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0082] The electrolyte acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Those skilled in the art can select the type of electrolyte based on actual conditions.

[0083] The insulating film 40 can be a thin film structure with insulating properties. By setting the insulating film 40 on the outer surface of the shell 20, the insulating ability of the shell 20 can be improved, so that the battery cell 7 has good insulating ability and is not prone to short circuit with adjacent battery cells 7, which is beneficial to improving the reliability of the battery 2.

[0084] For example, the insulating film 40 may be made of a material having insulating properties, such as plastic, rubber, etc., so as to have good insulating properties.

[0085] In the above structure, since the outer surface of the shell 20 of the battery cell 7 is provided with an insulating film 40 with insulating properties, the battery cell 7 has good insulation ability and is not prone to short circuit with adjacent battery cells 7, which is beneficial to improving the reliability of the battery 2.

[0086] In some embodiments, the melting point of the insulating film 40 is T, where T≧250° C.

[0087] Since the battery cells 7 in the battery 2 generate heat during operation, causing their own temperature to rise, especially when the battery cells 7 experience thermal runaway, the temperature of the battery cells 7 will rise rapidly, causing the insulating film 40 on the outer surface of the battery cell 7 housing 20 to melt. There is a risk that the housings 20 of two adjacent battery cells 7 will overlap, which can easily generate electric arcs and cause open flames.

[0088] By setting the melting point T of the insulating film 40 to a range of T≥250°C, the insulating film 40 is not easily melted even in a high temperature environment and can maintain its original structural state, so that the outer shell 20 of the battery cell 7 is not easily exposed, reducing the possibility of direct contact between the outer shells 20 of two adjacent battery cells 7, so that the battery cell 7 has good insulation ability even at high temperatures, is not easily short-circuited with adjacent battery cells 7, and is beneficial to improving the reliability of the battery 2.

[0089] In some embodiments, the melting point T of the insulating film 40 can be set to a range of 280°C ≤ T ≤ 400°C. This allows the insulating film 40 to have a relatively high melting point while also reducing the difficulty of manufacturing the insulating film 40 and thus helping to reduce the cost of the insulating film 40. For example, the melting point T of the insulating film 40 can be set to 300°C, 350°C, or 380°C. This prevents the insulating film 40 from melting even at relatively high temperatures, ensuring that the battery cell 7 has good insulation capabilities even at high temperatures and is less likely to short-circuit with adjacent battery cells 7, thereby improving the reliability of the battery 2.

[0090] In some embodiments, the dielectric strength of the insulating film 40 is P, where P≧10 kV / mm.

[0091] Dielectric strength is a measure of the electrical strength of a material as an insulator. It is the maximum voltage per unit thickness that a sample can withstand when it is broken down. By setting the dielectric strength P of the insulating film 40 to P ≥ 10 kV / mm, the insulating film 40 has excellent insulation properties and is not easily broken down. This isolation of the insulating film 40 reduces the likelihood of short circuits between adjacent battery cells 7, thus improving the reliability of the battery 2.

[0092] In some embodiments, the dielectric strength P of the insulating film 40 can be set to a range of 10 kV / mm ≤ P ≤ 30 kV / mm, so that the insulating film 40 has good insulation performance while also reducing the material cost of manufacturing the insulating film 40, thereby helping to reduce the cost of the insulating film 40. For example, the dielectric strength P of the insulating film 40 can be set to 15 kV / mm, 20 kV / mm, or 25 kV / mm, so that the insulating film 40 has good insulation performance without high cost, which is conducive to controlling the cost of the battery 2.

[0093] For example, the dielectric strength of the insulating film 40 can be obtained by measuring the insulating film 40 according to the national standard GB / T 1408.1-2006. The specific measurement method can refer to the national standard GB / T 1408.1-2006 and will not be described in detail here.

[0094] In some embodiments, as shown in FIG. 4 , the insulating film 40 includes a first film layer 401 and a second film layer 402 stacked together. The first film layer 401 is disposed on the outer surface of the housing 20 , and the second film layer 402 is disposed on a side of the first film layer 401 away from the housing 20 .

[0095] The first film layer 401 and the second film layer 402 can be different structural layers in the insulating film 40. The first film layer 401 and the second film layer 402 are stacked in the thickness direction of the insulating film 40 to form the insulating film 40. Specifically, the first film layer 401 can be a structural layer connected to the outer surface of the housing 20, and the second film layer 402 can be disposed on the side of the first film layer 401 away from the housing 20. By stacking the first film layer 401 and the second film layer 402, the insulating film 40 is composed of at least two structural layers, resulting in a composite film structure. This facilitates adjusting the performance parameters of different film structures to better meet various requirements.

[0096] Exemplarily, the number of layers of the first film layer 401 and the number of layers of the second film layer 402 can be set to one layer or to at least two layers. Those skilled in the art can set them according to actual conditions so that the stacked multi-layer first film layer 401 and the second film layer 402 can work together to meet the requirements of the insulating film 40.

[0097] In some embodiments, the hardness of the second film layer 402 is higher than that of the first film layer 401 .

[0098] The hardness of the second film layer 402 may refer to the Brinell hardness of the second film layer 402, and the hardness of the first film layer 401 may refer to the Brinell hardness of the first film layer 401. Since the second film layer 402 is disposed on the outer side of the first film layer 401 away from the housing 20, by configuring the hardness of the second film layer 402 to be higher than the hardness of the first film layer 401, the structural layer of the insulating film 40 away from the housing 20 has a higher hardness, which can better protect the internal structural layer of the insulating film 40, not only improving the wear resistance of the insulating film 40, but also reducing the possibility of damage to the insulating film 40 due to bumps and scratches, thereby helping to extend the service life of the insulating film 40.

[0099] Exemplarily, the measurement of the hardness of the second film layer 402 and the hardness of the first film layer 401 can be carried out separately in a separated state where the second film layer 402 and the first film layer 401 have not formed the insulating film 40. In this state, the second film layer 402 and the first film layer 401 are separated, and the hardness of the second film layer 402 and the hardness of the first film layer 401 can be conveniently measured separately. The measurement of the hardness of the second film layer 402 and the hardness of the first film layer 401 can also be carried out by disassembling the insulating film 40 to separate the second film layer 402 and the first film layer 401, so that the hardness of the second film layer 402 and the hardness of the first film layer 401 can be conveniently measured separately.

[0100] For example, the hardness of the second film layer 402 can be measured according to the national standard GB / T 231.1-2002. The specific measurement method can be referred to the national standard GB / T 231.1-2002 and will not be described in detail here.

[0101] In some embodiments, the melting point of the first film layer 401 is T1, the melting point of the second film layer 402 is T2, and T1>T2.

[0102] By configuring the melting point T1 of the first film layer 401 to be higher than the melting point T2 of the second film layer 402, the first film layer 401 has better high-temperature resistance than the second film layer 402. Since the first film layer 401 is disposed on the outer surface of the housing 20, and the second film layer 402 is disposed on the side of the first film layer 401 away from the housing 20, the first film layer 401, which is closer to the housing 20 of the battery cell 7, heats up faster and reaches a higher temperature. By configuring the melting point T1 of the first film layer 401 to be higher than the melting point T2 of the second film layer 402, the first film layer 401 has better high-temperature resistance, making it less likely to melt due to excessive temperatures, thereby helping to improve the high-temperature resistance of the insulating film 40.

[0103] In some embodiments, the dielectric strength of the first film layer 401 is D1, where D1 is ≥ 10 kV / mm.

[0104] By configuring the dielectric strength D1 of the first film layer 401 to be D1 ≥ 10 kV / mm, the first film layer 401 can increase the dielectric strength of the insulating film 40 and improve the insulation performance of the insulating film 40. In some embodiments, the dielectric strength D1 of the first film layer 401 can be set to a range of 10 kV / mm ≤ P ≤ 30 kV / mm. This allows the first film layer 401 to have good insulation performance while also reducing the material cost of manufacturing the first film layer 401, thereby helping to reduce the cost of the first film layer 401. For example, the dielectric strength D1 of the first film layer 401 can be set to 15 kV / mm, 20 kV / mm, or 25 kV / mm. This allows the first film layer 401 to have good insulation performance without being expensive, which helps control the cost of the battery 2.

[0105] The measurement of the dielectric strength of the first film layer 401 can be performed as an independent structural film layer when the first film layer 401 has not formed the insulating film 40. In this state, the first film layer 401 is independent of the second film layer 402. The dielectric strength of the first film layer 401 can be conveniently measured by measuring the dielectric strength of the first film layer 401.

[0106] In some embodiments, the dielectric strength of the second film layer 402 is D2, where D2 is ≥ 10 kV / mm. By setting the range of the dielectric strength D1 of the first film layer 401 and the range of the dielectric strength D2 of the second film layer 402 to D1 ≥ 10 kV / mm and D2 ≥ 10 kV / mm, respectively, the dielectric strength P of the insulating film 40 formed by the stack of the first film layer 401 and the second film layer 402 can be within the range of P ≥ 10 kV / mm, which is beneficial for increasing the dielectric strength of the insulating film 40 and improving the insulation performance of the insulating film 40.

[0107] The dielectric strength D2 of the second film layer 402 can be set in the range of 10 kV / mm≤D2≤30 kV / mm, so that the second film layer 402 has good insulation performance while also reducing the material cost of manufacturing the second film layer 402, thereby helping to reduce the cost of the second film layer 402. For example, the dielectric strength D2 of the second film layer 402 can be set to 15 kV / mm, 20 kV / mm, or 25 kV / mm, so that the second film layer 402 has good insulation performance without high cost, which is conducive to controlling the cost of the battery 2.

[0108] In some embodiments, the surface oxidation index of the second film layer 402 is smaller than the surface oxidation index of the first film layer 401 .

[0109] The surface oxidation index is an indicator used to evaluate oxidation resistance. Because the second film layer 402 is located on the outside of the first film layer 401, away from the housing 20, and by setting the surface oxidation index of the second film layer 402 to be lower than that of the first film layer 401, the second film layer 402, located on the outer surface of the insulating film 40, has stronger oxidation resistance. This improves the oxidation resistance of the outer surface of the insulating film 40 that contacts air, thereby extending the service life of the insulating film 40.

[0110] The surface oxidation index can be calculated by the mass change in air at a certain temperature. The smaller the value of the surface oxidation index, the stronger the antioxidant ability.

[0111] In some embodiments, the thickness of the first film layer 401 is greater than the thickness of the second film layer 402 .

[0112] Since the first film layer 401 is arranged on the inner side of the second film layer 402, and the melting point T1 of the first film layer 401 is higher than the melting point T2 of the second film layer 402, by setting the thickness of the first film layer 401 to be greater than the thickness of the second film layer 402, the thickness of the structural layer with a higher melting point is greater than the thickness of the structural layer with a lower melting point, thereby improving the high temperature resistance of the insulating film 40, which is beneficial to improving the high temperature resistance of the insulating film 40.

[0113] In some embodiments, the ratio of the thickness of the second film layer 402 to the thickness of the first film layer 401 is R, and 0.25≤R≤0.5.

[0114] By setting the ratio R of the thickness of the second film layer 402 to the thickness of the first film layer 401 to 0.25≤R≤0.5, the first film layer 401 can occupy a larger portion in the insulating film 40, which helps to further improve the high temperature resistance of the insulating film 40.

[0115] In some embodiments, the ratio R of the thickness of the second film layer 402 to the thickness of the first film layer 401 is set in the range of 0.3≤R≤0.5, so that the first film layer 401 can occupy a larger portion in the insulating film 40. For example, the ratio R of the thickness of the second film layer 402 to the thickness of the first film layer 401 can be set to 0.4, 0.45, or 0.5, so that the first film layer 401 can occupy a larger portion in the insulating film 40.

[0116] In some embodiments, the first film layer 401 is a polyimide film layer, and the second film layer 402 is a polyethylene terephthalate film layer.

[0117] The polyimide film layer may refer to a film structure made of polyimide, and the polyethylene terephthalate film layer may refer to a film structure made of polyethylene terephthalate. Since polyimide has a higher melting point and a higher surface oxidation index than polyethylene terephthalate, configuring the first film layer 401 as a polyimide film layer and configuring the second film layer 402 as a polyethylene terephthalate film layer not only effectively improves the oxidation resistance of the outer surface of the insulating film 40, but also helps to improve the high-temperature resistance of the insulating film 40.

[0118] In some embodiments, the thickness of the first film layer 401 is L1, 20 μm≤L1≤180 μm; and / or the thickness of the second film layer 402 is L2, 20 μm≤L2≤120 μm.

[0119] For example, the range of the thickness L1 of the first film layer 401 can be set to 20μm≤L1≤180μm, and the range of the thickness L2 of the second film layer 402 can be set to 20μm≤L2≤120μm; the range of the thickness L1 of the first film layer 401 can be set to 20μm≤L1≤180μm, while the range of the thickness L2 of the second film layer 402 is not specifically limited, and those skilled in the art can set it according to actual conditions; the range of the thickness L2 of the second film layer 402 can be set to 20μm≤L2≤120μm, while the range of the thickness L1 of the first film layer 401 is not specifically limited, and those skilled in the art can set it according to actual conditions.

[0120] By setting the thickness L1 of the first film layer 401 within the range of 20 μm ≤ L1 ≤ 180 μm, not only does the first film layer 401 have a certain structural strength, facilitating manufacturing, but it also helps reduce the cost of the first film layer 401. In some embodiments, the thickness L1 of the first film layer 401 is set within the range of 25 μm ≤ L1 ≤ 150 μm, ensuring that the first film layer 401 has sufficient strength while also having a low cost. For example, the thickness L1 of the first film layer 401 can be set to 50 μm, 80 μm, or 100 μm, ensuring that the first film layer 401 has good manufacturability while also having a low cost.

[0121] By setting the thickness L2 of the second film layer 402 within the range of 20 μm ≤ L2 ≤ 120 μm, not only does the second film layer 402 have a certain structural strength, facilitating manufacturing, but it also helps control the cost of the second film layer 402. In some embodiments, the thickness L2 of the second film layer 402 is set within the range of 20 μm ≤ L2 ≤ 120 μm, ensuring that the second film layer 402 has sufficient strength while also having a low cost. For example, the thickness L1 of the second film layer 402 can be set to 25 μm, 35 μm, or 50 μm, ensuring that the second film layer 402 has good manufacturability while protecting the internal structure of the insulating film 40.

[0122] In some embodiments, the insulating film 40 further includes a first adhesive layer 403 and a second adhesive layer 404 . The first adhesive layer 403 is bonded between the second film layer 402 and the first film layer 401 , and the second adhesive layer 404 is bonded between the first film layer 401 and the housing 20 .

[0123] The first adhesive layer 403 and the second adhesive layer 404 can be different adhesive layers provided in the insulating film 40 for bonding. The first adhesive layer 403 serves as an adhesive connecting the second film layer 402 and the first film layer 401, and is bonded between the second film layer 402 and the first film layer 401, thereby achieving a stacked connection between the second film layer 402 and the first film layer 401. The second adhesive layer 404 serves as an adhesive connecting the first film layer 401 and the housing 20, and is bonded between the first film layer 401 and the housing 20, thereby achieving a connection between the insulating film 40 and the outer surface of the housing 20.

[0124] In some embodiments, the adhesive strength of the first adhesive layer 403 is greater than the adhesive strength of the second adhesive layer 404 .

[0125] By setting the bonding strength of the first adhesive layer 403 to be greater than the bonding strength of the second adhesive layer 404, the peeling strength between the second film layer 402 and the first film layer 401 is greater than the peeling strength between the first film layer 401 and the outer shell 20, and the bonding force between the second film layer 402 and the first film layer 401 is greater than the bonding force between the first film layer 401 and the outer shell 20, so that in the process of peeling the insulating film 40 from the outer shell 20, the first adhesive layer 403 and the second adhesive layer 404 are not easy to separate, making it easy to peel the insulating film 40 from the outer shell 20.

[0126] For example, the adhesive strength of the first adhesive layer 403 can be measured by the interlayer peel strength between the second film layer 402 and the first film layer 401, and the adhesive strength of the second adhesive layer 404 can be measured by the interlayer peel strength between the first film layer 401 and the housing 20. For example, the interlayer peel strength can be measured according to the national standard GB / T 2792-2014. The specific measurement method can be referred to the national standard GB / T 2792-2014 and will not be repeated here.

[0127] In some embodiments, the interlayer peeling strength between the second adhesive layer 404 and the first film layer 401 is A, and the interlayer peeling strength between the second adhesive layer 404 and the housing 20 is B, where A>B.

[0128] By setting the interlayer peeling strength B between the second adhesive layer 404 and the shell 20 to be greater than the interlayer peeling strength A between the second adhesive layer 404 and the first film layer 401, the bonding force between the second adhesive layer 404 and the first film layer 401 is greater than the bonding force between the second adhesive layer 404 and the shell 20, so that in the process of peeling the insulating film 40 from the shell 20, the second adhesive layer 404 is not easily separated from the first film layer 401, so that the second adhesive layer 404 can be easily peeled from the shell 20, which facilitates the cleaning of the second adhesive layer 404.

[0129] For example, the interlayer peeling strength B between the second adhesive layer 404 and the shell 20 and the interlayer peeling strength A between the second adhesive layer 404 and the first film layer 401 can be measured according to the national standard GB / T 2792-2014. The specific measurement method can be referred to the national standard GB / T 2792-2014 and will not be repeated here.

[0130] In some embodiments, the interlayer peeling strength between the first adhesive layer 403 and the second film layer 402 is C, the interlayer peeling strength between the first adhesive layer 403 and the first film layer 401 is D, the interlayer peeling strength between the second adhesive layer 404 and the first film layer 401 is A, and the interlayer peeling strength between the second adhesive layer 404 and the outer shell 20 is B, A ≥ 300 N / m, B ≥ 300 N / m, C ≥ 300 N / m, and D ≥ 300 N / m.

[0131] By setting the range of the interlayer peel strength C between the first adhesive layer 403 and the second film layer 402 to C≥300N / m, setting the range of the interlayer peel strength D between the first adhesive layer 403 and the first film layer 401 to D≥300N / m, setting the range of the interlayer peel strength A between the second adhesive layer 404 and the first film layer 401 to A≥300N / m, and setting the range of the interlayer peel strength B between the second adhesive layer 404 and the outer shell 20 to B≥300N / m, the first adhesive layer 403 and the second adhesive layer 404 are firmly bonded, and the first adhesive layer 403 is firmly bonded to the outer shell 20, which not only makes it difficult for the insulating film 40 to fall off from the outer shell 20, but also makes it difficult for the insulating film 40 to be delaminated, which is beneficial to improving the structural integrity of the insulating film 40 and facilitates the insulating film 40 to be completely peeled off from the outer shell 20 by tearing or the like.

[0132] In some embodiments, A ≥ 350 N / m, B ≥ 350 N / m, C ≥ 350 N / m, and D ≥ 350 N / m.

[0133] By setting the range of the interlayer peel strength A between the second adhesive layer 404 and the first film layer 401 to A≥350N / m, setting the range of the interlayer peel strength B between the second adhesive layer 404 and the outer shell 20 to B≥350N / m, setting the range of the interlayer peel strength C between the first adhesive layer 403 and the second film layer 402 to C≥350N / m, and setting the range of the interlayer peel strength D between the first adhesive layer 403 and the first film layer 401 to D≥350N / m, the adhesion strength between the first adhesive layer 403 and the second adhesive layer 404 and the adhesion strength between the first adhesive layer 403 and the outer shell 20 can be further improved, making it difficult for the insulating film 40 to fall off from the outer shell 20 and also difficult for the insulating film 40 to be delaminated, so that the insulating film 40 can be completely peeled off from the outer shell 20.

[0134] In some embodiments, the second adhesive layer 404 includes a pressure-sensitive adhesive.

[0135] Since the pressure-sensitive adhesive can quickly adhere to the surface of the adherend under pressure, and after destroying the adhesive surface of the adherend, the pressure-sensitive adhesive is not easy to contaminate the surface of the adherend, the insulating film 40 can be easily peeled off from the outer shell 20 and is not easy to contaminate the outer shell 20, so that the insulating film 40 of the battery cell 7 can be easily replaced.

[0136] For example, the pressure-sensitive adhesive may include an acrylate pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive, wherein the rubber-based pressure-sensitive adhesive may be a natural rubber pressure-sensitive adhesive, a synthetic rubber, a silicone pressure-sensitive adhesive, or a recycled rubber pressure-sensitive adhesive.

[0137] Some embodiments of the present application further provide a battery 2, which includes a battery cell 7 provided by the above technical solution.

[0138] Since the battery 2 includes the battery cells 7 provided by the above technical solution, short circuits are unlikely to occur between adjacent battery cells 7 in the battery 2, so that the battery cells 7 have good reliability.

[0139] In some embodiments, the battery 2 further includes an isolator 50 , and multiple battery cells 7 are provided. The multiple battery cells 7 are stacked along a first direction, and an isolator 50 is sandwiched between the outer shells 20 of two adjacent battery cells 7 to space the two adjacent battery cells 7 apart.

[0140] By including multiple battery cells 7 and electrically connecting the multiple battery cells 7, the battery 2 can meet requirements for output voltage, power, and other factors. By stacking the multiple battery cells 7 along the first direction, the multiple battery cells 7 can fully utilize the space in the battery 2, which is conducive to improving the energy density of the battery 2.

[0141] By sandwiching the spacer 50 between the housings 20 of the two battery cells 7 , the two adjacent battery cells 7 can be spaced apart, which is beneficial to improving the insulation performance between the two adjacent battery cells 7 and further reducing the possibility of short circuit between the two adjacent battery cells 7 .

[0142] In some embodiments, spacer 50 comprises microcellular foamed polypropylene.

[0143] Microporous expanded polypropylene refers to a porous polypropylene foam material with pores less than 100 μm. Due to its porous structure, microporous expanded polypropylene can reduce the weight of separator 50, contributing to the lightweighting of battery 2. Polypropylene has excellent insulating properties, so including microporous expanded polypropylene in separator 50 ensures excellent insulating properties.

[0144] Since the thermal deformation temperature of microporous foamed polypropylene is relatively high, by making the separator 50 include microporous foamed polypropylene, the separator 50 has good high temperature resistance, so that the separator 50 can adapt to the heating of the battery cell 7.

[0145] In addition, the isolation member 50 sandwiched between the outer shells 20 of two adjacent battery cells 7 includes microporous foamed polypropylene, which not only allows the isolation member 50 to be squeezed and deformed when the battery cell 7 expands, thereby buffering and absorbing the expansion of the battery cell 7; it also allows the vibration and impact exerted on the battery cell 7 to be absorbed by the isolation member 50, which is beneficial to improving the reliability of the battery cell 7.

[0146] The cells in the microporous expanded polypropylene effectively reduce the convection of gas in the cells, thereby effectively reducing the heat transfer caused by air convection, so that the separator 50 can rely on the cell structure to maintain a low thermal conductivity for a long time.

[0147] 5 and 6 , the spacer 50 includes a frame 501 and an opening 502 enclosed by the frame 501. As shown in FIG7 , the frame 501 abuts against the insulating film 40 of the battery cell 7, and the opening 502 is positioned between two adjacent battery cells 7 to form an isolation cavity.

[0148] The frame 501 may be the main structure in the separator 50, which may serve as a frame structure in the separator 50. The frame 501 may support other structures in the separator 50 or form other structures in the separator 50. The opening 502 may be a spatial structure in the separator 50 that is not provided with material. When the separator 50 is sandwiched between the insulating films 40 of two adjacent battery cells 7, the opening 502 may form an isolation cavity between the two adjacent battery cells 7. Since the frame 501 is sandwiched between the insulating films 40 of two adjacent battery cells 7, the separator 50 not only increases the distance between the two adjacent battery cells 7, but the isolation cavity therein may also form an air layer between the insulating films 40 of the two adjacent battery cells 7, which is beneficial to improving the insulation performance between the two adjacent battery cells 7, further reducing the possibility of short circuits between the adjacent battery cells 7, and thus improving the reliability of the battery 2.

[0149] In some embodiments, as shown in FIG. 8 , a plurality of openings 502 are provided.

[0150] By distributing a plurality of openings 502 in the isolating member 50 , a frame 501 is provided between adjacent openings 502 . The frame 501 can enhance the structural strength of the isolating member 50 , thereby reducing the possibility of damage to the isolating member 50 .

[0151] Exemplarily, the plurality of openings 502 are evenly spaced in the isolation member 50 , so that the structural strength of each portion of the isolation member 50 is relatively uniform.

[0152] In some embodiments, the cross-sectional shape of the opening 502 can be set to a rectangle, a circle, a pentagon, an ellipse, etc. Those skilled in the art can set the cross-sectional shape of the opening 502 according to actual conditions.

[0153] Some embodiments of the present application further provide an electrical device, which includes the battery 2 provided by the above technical solution, and the battery 2 is used to provide electrical energy.

[0154] Some embodiments of the present application provide a battery cell 7, comprising an electrode assembly 30, a housing 20, and an insulating film 40. The electrode assembly 30 is housed in the housing 20, and the insulating film 40 is disposed on the outer surface of the housing 20. The melting point T of the insulating film 40 is set in the range of T ≥ 250°C, and the dielectric strength P of the insulating film 40 is set in the range of P ≥ 10 kV / mm. The insulating film 40 includes a first film layer 401 and a second film layer 402, which are stacked. The first film layer 401 is disposed on the outer surface of the housing 20, and the second film layer 402 is disposed on the side of the first film layer 401 away from the housing 20. The melting point T1 of the first film layer 401 is greater than the melting point T2 of the second film layer 402. The ratio of the thickness of the second film layer 402 to the thickness of the first film layer 401 is R, and the ratio is 0.25≤R≤0.5. The first film layer 401 is a polyimide film layer, and the second film layer 402 is a polyethylene terephthalate film layer. Since the outer surface of the battery cell 7 housing 20 in the above structure is provided with an insulating film 40 with insulating properties, the battery cell 7 has good insulation capability and is not prone to short circuit with adjacent battery cells 7, which is beneficial to improving the reliability of the battery 2.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, comprising: electrode assembly; a housing in which the electrode assembly is housed; The insulating film is arranged on the outer surface of the shell.

2. The battery cell according to claim 1, wherein: The melting point of the insulating film is T, and T≥250°C.

3. The battery cell according to claim 1 or 2, wherein: The dielectric strength of the insulating film is P, where P is ≥ 10 kV / mm.

4. The battery cell according to any one of claims 1 to 3, wherein: The insulating film includes a first film layer and a second film layer that are stacked. The first film layer is arranged on the outer surface of the shell, and the second film layer is arranged on a side of the first film layer away from the shell.

5. The battery cell according to claim 4, wherein: The hardness of the second film layer is higher than that of the first film layer.

6. The battery cell according to claim 4 or 5, wherein: The melting point of the first film layer is T1, the melting point of the second film layer is T2, and T1>T2.

7. The battery cell according to any one of claims 4 to 6, wherein: The dielectric strength of the first film layer is D1, and D1 is ≥ 10 kV / mm.

8. The battery cell according to any one of claims 4 to 7, wherein: The surface oxidation index of the second film layer is smaller than the surface oxidation index of the first film layer.

9. The battery cell according to any one of claims 4 to 8, wherein: The thickness of the first film layer is greater than the thickness of the second film layer.

10. The battery cell according to claim 9, wherein: The ratio of the thickness of the second film layer to the thickness of the first film layer is R, and 0.25≤R≤0.

5.

11. The battery cell according to any one of claims 4 to 10, wherein: The first film layer is a polyimide film layer, and the second film layer is a polyethylene terephthalate film layer.

12. The battery cell according to any one of claims 4 to 11, wherein: The thickness of the first film layer is L1, 20 μm≤L1≤180 μm; and / or the thickness of the second film layer is L2, 20 μm≤L2≤120 μm.

13. The battery cell according to any one of claims 4 to 12, wherein: The insulating film further includes a first adhesive layer and a second adhesive layer, wherein the first adhesive layer is bonded between the second film layer and the first film layer, and the second adhesive layer is bonded between the first film layer and the housing.

14. The battery cell according to claim 13, wherein: The bonding strength of the first adhesive layer is greater than the bonding strength of the second adhesive layer.

15. The battery cell according to claim 13 or 14, wherein: The interlayer peeling strength between the second adhesive layer and the first film layer is A, and the interlayer peeling strength between the second adhesive layer and the outer shell is B, where A>B.

16. The battery cell according to any one of claims 13 to 15, wherein: The interlayer peeling strength between the first adhesive layer and the second film layer is C, the interlayer peeling strength between the first adhesive layer and the first film layer is D, the interlayer peeling strength between the second adhesive layer and the first film layer is A, and the interlayer peeling strength between the second adhesive layer and the outer shell is B, A≥300N / m, B≥300N / m, C≥300N / m, and D≥300N / m.

17. The battery cell according to claim 16, wherein: A≥350N / m, B≥350N / m, C≥350N / m, D≥350N / m.

18. The battery cell according to any one of claims 13 to 17, wherein: The second adhesive layer includes pressure-sensitive adhesive.

19. A battery comprising the battery cell according to any one of claims 1 to 18.

20. The battery according to claim 19, wherein It also includes an isolating member. There are multiple battery cells, and the multiple battery cells are stacked along a first direction. The isolating member is sandwiched between the shells of two adjacent battery cells to space the two adjacent battery cells apart.

21. The battery according to claim 20, wherein The spacer comprises microcellular expanded polypropylene.

22. The battery according to claim 20 or 21, wherein The isolation member includes a frame and an opening surrounded by the frame. The frame is supported by the insulating film of the battery cell. The opening is located between two adjacent battery cells to form an isolation cavity.

23. The battery according to claim 22, wherein There are a plurality of openings.

24. An electrical device comprising the battery according to any one of claims 19 to 23, wherein the battery is used to provide electrical energy.

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