Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, the battery monomer comprises an electrode assembly, a shell and an insulating film, the electrode assembly is accommodated in the shell, and the insulating film is arranged on the outer surface of the shell. The outer surface of the shell of the battery monomer is provided with the insulating film with insulating property, so that the battery monomer has good insulating capacity, is not easy to generate short circuit with the adjacent battery monomer, and is beneficial to improving the reliability of the battery.

Description

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, electric tools, etc.

[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. Utility Model Content

[0004] 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 capability, which is beneficial to improving the reliability of the battery.

[0005] 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.

[0006] In the above structure, since the outer surface of the battery cell housing is provided with an insulating film having insulating properties, the battery cell has good insulating ability and is not prone to short circuit with adjacent battery cells, which is beneficial to improving the reliability of the battery.

[0007] 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 the 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 beneficial to improving the reliability of the battery.

[0008] 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 properties 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.

[0009] According to the battery cell provided in some embodiments of the present application, the insulating film includes a first film layer and a second film layer which are stacked, the first film layer is arranged on the outer surface of the shell, and the second film layer is arranged on the side of the first film layer away from the shell. By making the insulating film consist of the first film layer and the second film layer stacked, the insulating film is composed of at least two structural layers, so that the insulating film is a composite film layer structure, which facilitates adjusting the performance parameters of different film layer structures so that the insulating film better meets various requirements.

[0010] According to the battery cell provided in some embodiments of the present application, the hardness of the second film layer is higher than that of the first film layer. Since the second film layer is disposed on the outer side of the first film layer away from the outer shell, by configuring the hardness of the second film layer to be higher than that of 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, which is not only conducive to improving the wear resistance of the insulating film, but also conducive to reducing the possibility of the insulating film being damaged due to bumps and scratches, and helps to extend the service life of the insulating film.

[0011] According to the battery cell provided in some embodiments of the present application, the melting point of the first film layer is T1, the melting point of the second film layer is T2, and T1>T2. Since the first film layer is arranged on the outer surface of the shell, and the second film layer is arranged on the side of the first film layer away from the shell, the first film layer closer to the shell of the battery cell heats up faster and the temperature will also be higher. By configuring the melting point T1 of the first film layer to be higher than the melting point T2 of the second film layer so that the first film layer has better high temperature resistance, the first film layer is not easily melted due to excessive temperature, which helps to improve the high temperature resistance of the insulating film.

[0012] 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.

[0013] According to the battery cell provided in some embodiments of the present application, the surface oxidation index of the second film layer is less than the surface oxidation index of the first film layer. Since the second film layer is arranged on the outer side of the first film layer away from the outer shell, by setting the surface oxidation index of the second film layer to be less than the surface oxidation index of the first film layer, the second film layer located on the outer layer of the insulating film has stronger oxidation resistance, and the oxidation resistance of the outer side of the insulating film in contact with the air is improved, which is conducive to extending the service life of the insulating film.

[0014] According to the battery cell 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. Since the first film layer is arranged on the inner side of 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 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, which is beneficial to improving the high temperature resistance of the insulating film.

[0015] 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.

[0016] According to the battery cell 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. Since polyimide has a higher melting point and a higher surface oxidation index than polyethylene terephthalate, setting the first film layer as a polyimide film layer and setting the second film layer as a polyethylene terephthalate film layer can not only effectively improve the anti-oxidation performance of the outer surface of the insulating film, but also help to improve the high temperature resistance of the insulating film.

[0017] 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.

[0018] 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.

[0019] 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 peel strength between the second film layer and the first film layer is greater than the peel 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, so that the insulating film is easy to peel off from the outer shell.

[0020] 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.

[0021] 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 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 facilitating the insulating film to be completely peeled off from the outer shell by tearing or the like.

[0022] According to the battery cells provided in some embodiments of the present application, A≥350N / m, B≥350N / m, C≥350N / m, and D≥350N / m, the bonding strength between the first adhesive layer and the second adhesive layer, and the bonding strength between the first adhesive layer and the outer shell can be further improved, so that the insulating film is not easy to fall off the outer shell and is not easy to delaminate, which facilitates the insulating film to be completely peeled off from the outer shell.

[0023] 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.

[0024] In a second aspect, some embodiments of the present application provide a battery, which includes a battery cell provided by any of the above technical solutions.

[0025] Since the battery includes the battery cells provided by the above technical solution, short circuits are not likely to occur between adjacent battery cells in the battery, so that the battery cells have good reliability.

[0026] According to the battery provided in some embodiments of the present application, the battery further includes an isolating member, a plurality of battery cells are provided, the plurality of battery cells are stacked along a first direction, and an isolating member is sandwiched between the shells of two adjacent battery cells so that the two adjacent battery cells are spaced apart.

[0027] 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.

[0028] 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.

[0029] 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 placed between two adjacent battery cells to form an isolation cavity.

[0030] Since the frame is clamped between the insulating films of two adjacent battery cells, the isolation piece 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 is beneficial to improving the reliability of the battery.

[0031] According to some embodiments of the present application, the battery has multiple openings. By dispersing the openings in the separator into multiple openings, a frame is provided between adjacent openings, which can enhance the structural strength of the separator and reduce the possibility of damage to the separator.

[0032] According to the electrical device provided in 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.

[0033] The technical solution provided by the embodiments of the present disclosure brings at least the following beneficial effects:

[0034] The present application provides a battery cell, which includes an electrode assembly, a shell and an insulating film, wherein the electrode assembly is contained in the shell, and the insulating film is disposed on the outer surface of the shell. Since the outer surface of the shell of the battery cell is provided with an insulating film having insulating properties, the battery cell has good insulating ability and is not prone to short circuit with adjacent battery cells, which is conducive to improving the reliability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present application. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0036] Figure 1A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0037] Figure 2 A schematic diagram of the disassembled structure of a battery provided in some embodiments of the present application;

[0038] Figure 3 A schematic diagram of the disassembled structure of a battery cell provided in some embodiments of the present application;

[0039] Figure 4 A cross-sectional view of an insulating film in a battery cell provided in some embodiments of the present application;

[0040] Figure 5 A cross-sectional view of a separator in a battery provided in some embodiments of the present application;

[0041] Figure 6 A schematic diagram of the structure of an isolating element in a battery provided in some embodiments of the present application;

[0042] Figure 7 for Figure 5 Enlarged view of point E in the middle;

[0043] Figure 8 Schematic diagram of the structure of the isolation element in the battery provided in other embodiments of the present application.

[0044] In the figure:

[0045] 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 are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used 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 orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0049] In addition, the technical terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0050] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0051] In the description of the embodiments of the present application, unless otherwise clearly specified and 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. Moreover, a first feature being "above", "above" or "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 higher in level than the second feature. A first feature being "below", "below" or "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 lower in level than the second feature.

[0052] At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of battery application fields, people's requirements for batteries are also constantly increasing.

[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 may 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 cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery.

[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 accommodated 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, which includes an energy storage container, an energy storage cabinet, and the like.

[0061] In order to meet the requirements of output voltage, power and other factors, the battery is usually equipped with a large number of battery cells. In order to make full use of the internal space in the battery, multiple battery cells in the battery are usually arranged close to each other. This makes it possible for the shells of adjacent battery cells to overlap, and short circuits are likely to occur between adjacent battery cells.

[0062] In order to improve the insulation capacity of a battery cell and improve the reliability of the battery, some embodiments of the present application provide a battery cell, which includes an electrode assembly, a shell and an insulating film, wherein the electrode assembly is accommodated in the shell, and the insulating film is disposed on the outer surface of the shell. Since the outer surface of the shell of the battery cell is provided with an insulating film having insulating properties, the battery cell has good insulation capacity and is not prone to short circuit with adjacent battery cells, which is conducive to improving the reliability of the battery.

[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 may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, etc. Vehicles may be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc. Spacecraft include aircraft, rockets, space shuttles and spacecrafts, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc.

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

[0066] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0067] like Figure 1 As shown, a battery 2 is disposed inside the vehicle 1, and the battery 2 may be disposed 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 be used as an operating power source for the vehicle 1.

[0068] The vehicle 1 may further include a controller 3 and a motor 4 , wherein 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 starting, navigating, and driving the vehicle 1 .

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

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

[0071] The box 5 is used to accommodate the battery cell 7, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cell 7. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

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

[0074] In the battery 2, the battery cell 7 can be one or more. If there are more than one battery cell 7, the battery cells 7 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 7 are both connected in series and in parallel. The battery cells 7 can be directly connected in series, in parallel or in mixed connection, and then the whole formed by the battery cells 7 can be accommodated in the box 5; of course, the battery modules 6 can also be formed by connecting the battery cells 7 in series, in parallel or in mixed connection, and then the battery modules 6 can be formed into a whole by connecting the battery cells 7 in series, in parallel or in mixed connection, and then accommodated in the box 5.

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

[0076] like Figure 3 As shown, in some embodiments, the battery cell 7 includes a housing 20 and an electrode assembly 30. The electrode assembly 30 is accommodated in the housing 20.

[0077] The housing 20 may be in various shapes and sizes, such as a rectangular parallelepiped, a hexagonal prism, etc. Specifically, the shape of the housing 20 may be determined according to the specific shape and size of the electrode assembly 30. The housing 20 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the present embodiment of the application does not impose any special restrictions on this.

[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, such as Figure 3 As shown, the battery cell 7 includes an electrode assembly 30 , a housing 20 and an insulating film 40 . The electrode assembly 30 is accommodated 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 contained in the hollow structure surrounded by the housing 20, and may include a pole piece and a separator 50. The pole piece may include a positive pole piece or a negative pole piece with opposite polarities. The positive pole piece and the negative pole piece may serve as the positive electrode and the negative electrode, respectively. During the charge and discharge process of the battery cell 7, active ions (such as lithium ions) are intercalated and released between the positive electrode and the negative electrode. The separator 50 is stacked between the positive pole piece and the negative pole piece, and is used to isolate the positive pole piece and the negative pole piece, and can prevent the positive and negative electrodes from short-circuiting while allowing active ions to pass through.

[0082] The electrolyte plays the role of conducting ions between the positive electrode and the negative electrode. The electrolyte can be liquid, gel or solid. Those skilled in the art can select the type of electrolyte according to 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 capacity of the shell 20 can be improved, so that the battery cell 7 has good insulating capacity and is not easy to short-circuit with adjacent battery cells 7, which is beneficial to improving the reliability of the battery 2.

[0084] Exemplarily, the insulating film 40 may be made of a material having insulating properties, such as plastic, rubber, etc., so that it has 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 easy 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, making it possible for the insulating film 40 on the outer surface of the battery cell 7 housing 20 to melt, and there is a risk of overlapping of the housings 20 of two adjacent battery cells 7, which is prone to 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, so that the insulating film 40 has a higher melting point and is also conducive to reducing the difficulty of manufacturing the insulating film 40, which helps to reduce the cost of the insulating film 40. Exemplarily, the melting point T of the insulating film 40 can be set to 300°C, 350°C or 380°C, so that the insulating film 40 is not easy to melt even in a high temperature environment, so that the battery cell 7 has good insulation ability at high temperature, is not easy to short-circuit with adjacent battery cells 7, and is conducive to 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, which is the maximum voltage per unit thickness that a sample can withstand when it is broken down. By setting the range of the dielectric strength P of the insulating film 40 to P ≥ 10 kV / mm, the insulating film 40 has good insulation performance and is not easily broken down. Under the isolation effect of the insulating film 40, short circuits are not likely to occur between two adjacent battery cells 7, which is beneficial to the reliability of the battery 2.

[0092] In some embodiments, the range of the dielectric strength P of the insulating film 40 can be set to 10 kV / mm≤P≤30 kV / mm, so that the insulating film 40 has good insulation performance and is also conducive to reducing the material cost of manufacturing the insulating film 40, which helps to reduce the cost of the insulating film 40. Exemplarily, 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 can have good insulation ability and will not have a 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 / T1408.1-2006 and will not be described in detail here.

[0094] In some embodiments, Figure 4 As shown, 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 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 may 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. The first film layer 401 may be a structural layer connected to the outer surface of the housing 20, and the second film layer 402 may be arranged on the side of the first film layer 401 away from the housing 20. By making the insulating film 40 composed of the first film layer 401 and the second film layer 402 stacked, the insulating film 40 is composed of at least two structural layers, so that the insulating film 40 is a composite film layer structure, which is convenient for adjusting the performance parameters of different film layer structures so that the insulating film 40 better meets 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 the hardness 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, which is not only conducive to improving the wear resistance of the insulating film 40, but also conducive to reducing the possibility of the insulating film 40 being damaged due to bumps and scratches, and helps 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 when the second film layer 402 and the first film layer 401 are in a separated state without forming 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 obtained by measuring the second film layer 402 according to the national standard GB / T 231.1-2002. The specific measurement method can refer 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 arranged on the outer surface of the housing 20, and the second film layer 402 is arranged on the side of the first film layer 401 away from the housing 20, the first film layer 401 closer to the housing 20 of the battery cell 7 heats up faster and the temperature will also be higher. 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 so that the first film layer 401 has better high temperature resistance, the first film layer 401 is not easily melted due to excessive temperature, which helps 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 ≥ 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 improve the dielectric strength of the insulating film 40, and can improve the insulating performance of the insulating film 40. In some embodiments, the range of the dielectric strength D1 of the first film layer 401 can be set to 10 kV / mm ≤ P ≤ 30 kV / mm, so that the first film layer 401 has good insulation performance while also helping to reduce the material cost of manufacturing the first film layer 401, which helps to reduce the cost of the first film layer 401. Exemplarily, the dielectric strength D1 of the first film layer 401 can be set to 15 kV / mm, 20 kV / mm or 25 kV / mm, so that the first film layer 401 can have good insulation ability without having a high cost, which is conducive to controlling the cost of the battery 2.

[0105] The dielectric strength of the first film layer 401 can be measured as an independent structural film layer when the first film layer 401 has not formed an 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, and D2≥10kV / 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≥10kV / mm and D2≥10kV / mm respectively, the dielectric strength P of the insulating film 40 formed by the stacking of the first film layer 401 and the second film layer 402 can be in the range of P≥10kV / mm, which is conducive to improving the dielectric strength of the insulating film 40 and improving the insulation performance of the insulating film 40.

[0107] The range of the dielectric strength D2 of the second film layer 402 can be set to 10kV / mm≤D2≤30kV / mm, so that the second film layer 402 has good insulation performance and is also conducive to reducing the material cost of manufacturing the second film layer 402, which helps to reduce the cost of the second film layer 402. Exemplarily, the dielectric strength D2 of the second film layer 402 can be set to 15kV / mm, 20kV / mm or 25kV / mm, so that the second film layer 402 can have good insulation ability and will not have a 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 less than the surface oxidation index of the first film layer 401 .

[0109] The surface oxidation index is an indicator for evaluating the anti-oxidation performance. Since the second film layer 402 is disposed on the outer side of the first film layer 401 away from the housing 20, by setting the surface oxidation index of the second film layer 402 to be smaller than the surface oxidation index of the first film layer 401, the second film layer 402 located on the outer layer of the insulating film 40 has stronger anti-oxidation performance, thereby improving the anti-oxidation ability of the outer side of the insulating film 40 in contact with the air, which is beneficial to prolonging 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 a range of 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. Exemplarily, 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, setting the first film layer 401 as a polyimide film layer and setting the second film layer 402 as a polyethylene terephthalate film layer can not only effectively improve the anti-oxidation performance of the outer surface of the insulating film 40, but also help 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] Exemplarily, 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 range of the thickness L1 of the first film layer 401 to 20 μm ≤ L1 ≤ 180 μm, not only the first film layer 401 has a certain structural strength, which is convenient for manufacturing, but also helps to reduce the cost of the first film layer 401. In some embodiments, the range of the thickness L1 of the first film layer 401 is set to 25 μm ≤ L1 ≤ 150 μm, so that the first film layer 401 has sufficient strength and low cost. Exemplarily, the thickness L1 of the first film layer 401 can be set to 50 μm, 80 μm or 100 μm, so that the first film layer 401 has good manufacturability and low cost.

[0121] By setting the range of the thickness L2 of the second film layer 402 to 20 μm ≤ L2 ≤ 120 μm, not only the second film layer 402 has a certain structural strength, which is convenient for manufacturing, but also helps to control the cost of the second film layer 402. In some embodiments, the range of the thickness L2 of the second film layer 402 is set to 20 μm ≤ L2 ≤ 120 μm, so that the second film layer 402 has sufficient strength and low cost. Exemplarily, the thickness L1 of the second film layer 402 can be set to 25 μm, 35 μm or 50 μm, so that the second film layer 402 can protect the internal structure of the insulating film 40 while having good manufacturability.

[0122] In some embodiments, the insulating film 40 further includes a first adhesive layer 403 and a second adhesive layer 404 , wherein 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 may be different adhesive layers for bonding provided in the insulating film 40. The first adhesive layer 403 is bonded between the second film layer 402 and the first film layer 401 as an adhesive connecting the second film layer 402 and the first film layer 401, so as to realize the stacking connection of the second film layer 402 and the first film layer 401. The second adhesive layer 404 is bonded between the first film layer 401 and the outer shell 20 as an adhesive connecting the first film layer 401 and the outer shell 20, so as to realize the connection of the insulating film 40 on the outer surface of the outer shell 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 peel strength between the second film layer 402 and the first film layer 401 is greater than the peel 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, so that the insulating film 40 is easy to be peeled off from the outer shell 20.

[0126] For example, the bonding strength of the first adhesive layer 403 can be measured by the interlayer peeling strength between the second film layer 402 and the first film layer 401, and the bonding strength of the second adhesive layer 404 can be measured by the interlayer peeling strength between the first film layer 401 and the housing 20. For example, the interlayer peeling strength can be measured according to the national standard GB / T 2792-2014, and the specific measurement method can be carried out with reference to the national standard GB / T 2792-2014, which will not be described in detail 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, and A>B.

[0128] By setting the interlayer peeling strength B between the second adhesive layer 404 and the outer 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 outer shell 20, so that in the process of peeling the insulating film 40 from the outer 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 off from the outer shell 20, which facilitates the cleaning of the second adhesive layer 404.

[0129] For example, the interlayer peel strength B between the second adhesive layer 404 and the shell 20 and the interlayer peel 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 refer 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≥300N / m, B≥300N / m, C≥300N / m, and D≥300N / 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 and the outer shell 20 are firmly bonded, which not only makes it difficult for the insulating film 40 to fall off 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, so that the insulating film 40 is not easy to fall off from the outer shell 20 and is not easy to delaminate, 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 bonding 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 system pressure-sensitive adhesive, wherein the rubber system 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 isolating member 50 , and a plurality of battery cells 7 are provided. The plurality of battery cells 7 are stacked along a first direction, and an isolating member 50 is sandwiched between the housings 20 of two adjacent battery cells 7 to space the two adjacent battery cells 7 apart.

[0140] By making the battery 2 include a plurality of battery cells 7 and electrically connecting the plurality of battery cells 7, the battery 2 can meet the requirements of output voltage, power, etc. By stacking the plurality of battery cells 7 along the first direction, the plurality of battery cells 7 can make full use of the space in the battery 2, which is beneficial to improving the energy density of the battery 2.

[0141] By sandwiching the isolating member 50 between the housings 20 of two battery cells 7 , 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 foamed polypropylene refers to a polypropylene porous foam material with a pore size of less than 100 μm. Since microporous foamed polypropylene has a porous structure, it can reduce the weight of the separator 50, which is conducive to the lightweight of the battery 2. Since polypropylene has good insulation properties, the separator 50 includes microporous foamed polypropylene, so that the separator 50 has good insulation 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 isolation member 50 to absorb the vibration and impact exerted on the battery cell 7, 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 the gas in the cells, thereby effectively reducing the heat transfer caused by air convection, so that the isolation member 50 can rely on the cell structure to maintain a low thermal conductivity for a long time.

[0147] In some embodiments, Figure 5 and Figure 6 As shown, the isolating member 50 includes a frame 501 and an opening 502 surrounded by the frame 501. Figure 7 As shown, the frame 501 is against the insulating film 40 of the battery cell 7 , and the opening 502 is disposed 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 carry other structures in the separator 50 or form other structures in the separator 50. The opening 502 may be a space structure in the separator 50 where no material is provided. 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 the two adjacent battery cells 7, the separator 50 not only increases the distance between the two adjacent battery cells 7, but also the isolation cavity therein may 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 circuit between the adjacent battery cells 7, and is beneficial to improving the reliability of the battery 2.

[0149] In some embodiments, Figure 8 As shown, a plurality of openings 502 are provided.

[0150] By dispersing and 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 , which helps to reduce 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 rectangular, circular, pentagonal, elliptical, etc., and 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, which includes an electrode assembly 30, a shell 20 and an insulating film 40. The electrode assembly 30 is accommodated in the shell 20, and the insulating film 40 is arranged on the outer surface of the shell 20. The melting point T of the insulating film 40 is set to T≥250°C, and the dielectric strength P of the insulating film 40 is set to P≥10kV / mm. The insulating film 40 includes a first film layer 401 and a second film layer 402 stacked, wherein the first film layer 401 is arranged on the outer surface of the shell 20, and the second film layer 402 is arranged on the side of the first film layer 401 away from the shell 20. Among them, 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, 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 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.

[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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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, characterized in that: include: Electrode assembly; a housing in which the electrode assembly is accommodated; An insulating film is arranged on the outer surface of the shell, and the insulating film includes a first film layer and a second film layer which are stacked, the first film layer is arranged on the outer surface of the shell, and the second film layer is arranged on the side of the first film layer away from the shell; the insulating film also 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 shell; the bonding strength of the first adhesive layer is greater than the bonding strength of the second adhesive layer.

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

3. The battery cell according to claim 1, characterized in that: The dielectric strength of the insulating film is P, P≥10kV / mm.

4. The battery cell according to claim 1, characterized in that: The hardness of the second film layer is higher than that of the first film layer.

5. The battery cell according to claim 1, characterized in that: The melting point of the first film layer is T1, the melting point of the second film layer is T2, and T1>T2.

6. The battery cell according to claim 1, characterized in that: The dielectric strength of the first film layer is D1, and D1≥10 kV / mm.

7. The battery cell according to claim 1, characterized in that: The surface oxidation index of the second film layer is smaller than the surface oxidation index of the first film layer.

8. The battery cell according to claim 1, characterized in that: The thickness of the first film layer is greater than the thickness of the second film layer.

9. The battery cell according to claim 8, characterized in that: 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.

10. The battery cell according to claim 1, characterized in that: The first film layer is a polyimide film layer, and the second film layer is a polyethylene terephthalate film layer.

11. The battery cell according to claim 1, characterized in that: 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.

12. The battery cell according to claim 1, characterized in that: 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, and A>B.

13. The battery cell according to claim 1, characterized in that: 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.

14. The battery cell according to claim 13, characterized in that: A≥350N / m, B≥350N / m, C≥350N / m, D≥350N / m.

15. The battery cell according to claim 1, characterized in that: The second adhesive layer includes a pressure-sensitive adhesive.

16. A battery, characterized in that: Comprising the battery cell according to any one of claims 1 to 15.

17. The battery according to claim 16, characterized in that It also includes an isolating member. A plurality of the battery cells are provided. The plurality of the battery cells are stacked along a first direction. The isolating member is sandwiched between the shells of two adjacent battery cells so that the two adjacent battery cells are spaced apart.

18. The battery according to claim 17, characterized in that The spacer comprises microcellular foamed polypropylene.

19. The battery according to claim 17 or 18, characterized in that: The isolation member comprises 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 arranged between two adjacent battery cells to form an isolation cavity.

20. The battery according to claim 19, characterized in that There are a plurality of openings.

21. An electrical device, characterized in that: A battery comprising a battery as claimed in any one of claims 16 to 20, wherein the battery is used to provide electrical energy.

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