Battery monomer, battery device, power utilization device and energy storage device

Abstract

The embodiment of the utility model provides a battery monomer, a battery device, a power utilization device and an energy storage device, and belongs to the technical field of batteries. The battery cell includes a housing, an electrode assembly, a conductive terminal, a first insulating layer, and a second insulating layer. The electrode assembly is located in the shell, the conductive terminal is installed on the shell and electrically connected with the electrode assembly, the first insulating layer wraps the shell to insulate the outer surface of the shell, the shell is located in the first insulating layer, and the second insulating layer is arranged on the first insulating layer and located on the side, away from the electrode assembly, of the shell. The heat resistance of the second insulating layer is greater than that of the first insulating layer. The battery monomer provided by the utility model is beneficial to reducing the possibility of diffusion of thermal runaway between adjacent battery monomers.

Description

Technical Field

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

[0002] With the development of the new energy industry, multiple battery cells are often stacked in battery devices. When thermal runaway occurs in one of the battery cells, it may cause abnormal heat transfer and overlapping short circuits between adjacent battery cells, and there is a possibility of heat diffusion to a certain extent. Summary of the invention

[0003] In view of this, the embodiments of the present application are intended to provide a battery cell, a battery device, an electrical device, and an energy storage device, which are intended to reduce the possibility of heat diffusion between adjacent battery cells when thermal runaway occurs in the battery cell.

[0004] To achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:

[0005] The present application provides a battery cell, including:

[0006] shell;

[0007] an electrode assembly, located in the housing;

[0008] A conductive terminal is mounted on the housing, and the conductive terminal is electrically connected to the electrode assembly;

[0009] A first insulating layer, covering the outer shell to insulate the outer surface of the outer shell, the outer shell is located in the first insulating layer;

[0010] The second insulating layer is arranged on the first insulating layer, and the second insulating layer is located on the side of the shell away from the electrode assembly. The heat resistance of the second insulating layer is greater than that of the first insulating layer.

[0011] In the embodiments of the present application, the second insulating layer is disposed on the first insulating layer, and the second insulating layer is located on the side of the outer casing away from the electrode assembly, such that the second insulating layer can be located between the outer casings of two adjacent battery cells. When a battery cell undergoes thermal runaway, the second insulating layer, which has a better heat resistance to temperature, is not easily damaged under the high temperature generated by the battery cell in thermal runaway. The second insulating layer can limit the heat generated by the battery cell in thermal runaway from directly transferring to adjacent battery cells, which is conducive to reducing the speed of heat transfer between adjacent battery cells. Further, the second insulating layer, which is not easily damaged under the high temperature generated by the battery cell in thermal runaway, is conducive to reducing the possibility of direct contact between the outer casings of adjacent battery cells, and then is conducive to reducing the possibility of short-circuit caused by overlap between the outer casings of adjacent battery cells and high-voltage spark breakdown. Therefore, when a battery cell undergoes thermal runaway, setting the second insulating layer between the outer casings of adjacent battery cells is conducive to reducing the possibility of thermal runaway spreading between adjacent battery cells.

[0012] In one embodiment, the energy density of the battery cell is greater than or equal to 320 Wh / L and less than 390 Wh / L, and the heat-resistant temperature range of the second insulating layer is 180°C ≤ T ≤ 450°C.

[0013] In the embodiments of the present application, when the energy density range of the battery cell is 320 Wh / L to 390 Wh / L, the heat-resistant temperature range required for the second insulating layer is 180°C to 450°C. The heat-resistant temperature of the second insulating layer is relatively high to reduce the possibility of melting and perforation of the second insulating layer during the thermal runaway of the battery cell, which is conducive to limiting the heat generated by the battery cell in thermal runaway from directly transferring to the outer casing of adjacent battery cells, and then is conducive to reducing the possibility of thermal runaway spreading between adjacent battery cells.

[0014] In one embodiment, the energy density of the battery cell is greater than or equal to 390 Wh / L and less than 490 Wh / L, and the heat-resistant temperature range of the second insulating layer is 220°C ≤ T ≤ 450°C.

[0015] In the embodiments of the present application, when the energy density range of the battery cell is 390 Wh / L to 490 Wh / L, the heat-resistant temperature range required for the second insulating layer is 220°C to 450°C. The heat-resistant temperature of the second insulating layer is relatively high to reduce the possibility of melting and perforation of the second insulating layer during the thermal runaway of the battery cell, which is conducive to limiting the heat generated by the battery cell in thermal runaway from directly transferring to the outer casing of adjacent battery cells, and then is conducive to reducing the possibility of thermal runaway spreading between adjacent battery cells.

[0016] In one embodiment, the energy density of the battery cell is greater than or equal to 490 Wh / L and less than 550 Wh / L, and the heat-resistant temperature range of the second insulating layer is 250°C ≤ T ≤ 450°C.

[0017] In the embodiments of the present application, when the energy density range of the battery cell is 490 Wh / L to 550 Wh / L, the heat-resistant temperature range required for the second insulating layer is 250°C to 450°C. The heat-resistant temperature of the second insulating layer is relatively high, which can reduce the possibility of melting and perforation of the second insulating layer during the thermal runaway of the battery cell, and is beneficial to restricting the heat generated by the battery cell in thermal runaway from directly transferring to the outer shell of the adjacent battery cell, thereby reducing the possibility of thermal runaway diffusion between adjacent battery cells.

[0018] In one embodiment, the material of the first insulating layer is polyethylene terephthalate or polycarbonate, and the material of the second insulating layer is polypropylene, polyethylene, polyamide, polyethylene terephthalate, polyphthalamide, polyphenylene sulfide or polyimide.

[0019] In the embodiments of the present application, the material of the first insulating layer is polyethylene terephthalate or polycarbonate, which has good physical and mechanical properties, insulation properties and waterproof properties, and is beneficial to improving the safety of the battery cell. The material of the second insulating layer is polypropylene, polyethylene, polyamide, polyethylene terephthalate, polyphthalamide, polyphenylene sulfide or polyimide. Polyimide has good temperature tolerance performance, which is beneficial to the second insulating layer restricting the heat generated by the battery cell in thermal runaway from directly transferring to the adjacent battery cell, and is beneficial to reducing the heat transfer rate between adjacent battery cells.

[0020] In one embodiment, the energy density of the battery cell is greater than or equal to 320 Wh / L and less than 390 Wh / L, and the thickness of the second insulating layer is 50 μm to 700 μm.

[0021] In the embodiments of the present application, when the energy density range of the battery cell is 320 Wh / L to 390 Wh / L, the required thickness range of the second insulating layer is 50 μm to 700 μm. The thickness of the second insulating layer is relatively thick, which can reduce the possibility of melting and perforation of the second insulating layer during the thermal runaway of the battery cell, and is beneficial to restricting the heat generated by the battery cell in thermal runaway from directly transferring to the adjacent battery cell, thereby reducing the possibility of thermal runaway diffusion between adjacent battery cells. On the other hand, the second insulating layer with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film under the normal use state of the battery cell.

[0022] In one embodiment, the energy density of the battery cell is greater than or equal to 390 Wh / L and less than 490 Wh / L, and the thickness of the second insulating layer is 70 μm to 700 μm.

[0023] In the embodiments of the present application, when the energy density range of the battery cell is 390 Wh / L to 490 Wh / L, the required thickness range of the second insulating layer is 70 μm to 700 μm. The relatively thick second insulating layer is beneficial to reducing the possibility of melting and perforation of the second insulating layer during thermal runaway of the battery cell, beneficial to restricting the heat generated by the battery cell in thermal runaway from directly transferring to adjacent battery cells, and then beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells; on the other hand, the second insulating layer with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film during the normal use of the battery cell.

[0024] In one embodiment, the energy density of the battery cell is greater than or equal to 490 Wh / L and less than 550 Wh / L, and the thickness of the second insulating layer is 100 μm to 700 μm.

[0025] In the embodiments of the present application, when the energy density range of the battery cell is 490 Wh / L to 550 Wh / L, the required thickness range of the second insulating layer is 100 μm to 700 μm. The relatively thick second insulating layer is beneficial to reducing the possibility of melting and perforation of the second insulating layer during thermal runaway of the battery cell, beneficial to restricting the heat generated by the battery cell in thermal runaway from directly transferring to adjacent battery cells, and then beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells; on the other hand, the second insulating layer with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film during the normal use of the battery cell.

[0026] In one embodiment, the largest outer surface of the outer shell is a preset surface, the direction perpendicular to the preset surface is the first direction, and the second insulating layer is at least partially located on at least one side of the outer shell along the first direction.

[0027] In the embodiment of the present application, when a battery cell undergoes thermal runaway, the second insulating layer can limit the heat generated by the battery cell in thermal runaway from directly transferring to adjacent battery cells, which is beneficial to reducing the heat transfer rate between adjacent battery cells. The second insulating layer is at least partially located on at least one side of the outer shell along the first direction. The second insulating layer can cover the remaining surfaces of the battery cell body except for the preset surface, which is beneficial to reducing the volume occupied by the second insulating layer, and then beneficial to improving the space utilization rate inside the battery device. The heat generated by the battery cell in the normal use state can be dissipated through the surface on the side of the outer shell facing away from the conductive terminal, which is beneficial to improving the heat dissipation efficiency of the battery cell. The remaining sides of the outer shell except for the preset surface are not covered by the second insulating layer, which is also beneficial to improving the bonding strength between the remaining sides of the outer shell except for the preset surface and the remaining sides of the outer shell of the adjacent battery cell.

[0028] In one embodiment, the second insulating layer is annular in shape. The second insulating layer encloses a receiving cavity and an opening communicating with the receiving cavity. Openings are provided on both opposite sides of the receiving cavity, and the outer shell is located in the receiving cavity corresponding to the second insulating layer.

[0029] In the embodiment of the present application, when a battery cell undergoes thermal runaway, the second insulating layer can limit the heat generated by the battery cell in thermal runaway from directly transferring to adjacent battery cell bodies, which is beneficial to reducing the heat transfer rate between adjacent battery cell bodies. Openings are provided on both opposite sides of the receiving cavity enclosed by the annular second insulating layer, and the outer shell is located in the receiving cavity, such that the second insulating layer straddles the preset surface of the outer shell and the remaining sides except for the preset surface of the outer shell. The surface on the side of the outer shell facing away from the conductive terminal is not covered by the second insulating layer. The heat generated by the battery cell in the normal use state can be dissipated through the surface on the side of the outer shell facing away from the conductive terminal, which is beneficial to improving the heat dissipation efficiency of the battery cell.

[0030] In one embodiment, the second insulating layer includes a main film and a first sub-film. The main films are provided on both opposite sides of the outer shell along the first direction, and the first sub-film is connected between the main films on the corresponding two sides. The arrangement direction of the conductive terminal and the electrode assembly is the second direction, and the second direction intersects with the first direction. The first sub-film is located on the side of the outer shell along the second direction facing away from the conductive terminal.

[0031] In the embodiment of the present application, when a battery cell experiences thermal runaway, the second insulating layer can limit the heat generated by the battery cell in thermal runaway from being directly transferred to the adjacent battery cell, which is beneficial to reducing the speed of heat transfer between adjacent battery cells. The main film is arranged on a preset surface, and the first sub-film is located on the side of the shell away from the conductive terminal along the second direction, so that the second insulating layer is arranged across the preset surface of the shell and the surface of the shell away from the conductive terminal. The remaining sides of the shell except the preset surface are not covered by the second insulating layer. The heat generated by the battery cell in normal use can be dissipated through the remaining sides of the shell except the preset surface, which is beneficial to improving the heat dissipation efficiency of the battery cell. The remaining sides of the shell except the preset surface are not covered by the second insulating layer, which is also beneficial to improving the bonding strength between the remaining sides of the shell except the preset surface and the remaining sides of the adjacent shell except the preset surface.

[0032] In one embodiment, the second insulating layer also includes a second sub-membrane, and the second sub-membrane is arranged on opposite sides of the outer shell along a third direction, the third direction is respectively arranged to cross the first direction and the second direction, the first direction, the second direction and the third direction are not coplanar, the second sub-membrane is respectively connected to the first sub-membrane and the main membrane on both sides, the second sub-membrane on each side forms an avoidance cavity, and the space enclosed by the main membrane, the first sub-membrane and the second sub-membrane is connected to the avoidance cavity.

[0033] In the embodiment of the present application, the second sub-membrane is connected to the first sub-membrane and the main membranes on both sides respectively, so that the main membrane, the first sub-membrane and the second sub-membrane form a relatively stable constraint on the outer shell, which is conducive to fixing the outer shell more firmly.

[0034] In one embodiment, when projected along the second direction, a projection area of ​​a surface of the housing on one side facing away from the conductive terminal along the second direction is located within a projection area of ​​the first sub-film.

[0035] In an embodiment of the present application, the projection area of ​​the surface of the shell along the second direction away from the conductive terminal is located within the projection area of ​​the first sub-membrane, so that the first sub-membrane can completely cover the surface of the shell along the second direction away from the conductive terminal. When thermal runaway occurs in the battery cell, the first sub-membrane with better temperature resistance can isolate the surface of the shell along the second direction away from the conductive terminal, which is beneficial to reduce the possibility of heat diffusion between two adjacent battery cells.

[0036] In one embodiment, the thickness of the main film is greater than the thickness of the first sub-film.

[0037] In an embodiment of the present application, when a battery cell experiences thermal runaway, the temperature of the preset surface is generally greater than the temperature of the remaining surfaces of the outer shell excluding the preset surface, and the thickness of the main film arranged on the preset surface is greater than the thickness of the first sub-film arranged on the surface of the outer shell away from the conductive terminal along the second direction. On the one hand, using second insulating layers of different thicknesses for different outer shell surfaces is beneficial to reducing the production cost of the battery cell; on the other hand, a main film with a larger thickness is beneficial to thermal insulation between adjacent battery cells.

[0038] In one embodiment, the first sub-membrane is located between the housing and the thermal management component.

[0039] In the embodiment of the present application, the thinner first sub-membrane is located between the outer shell and the thermal management component, so that the surface arranged on the side of the outer shell away from the conductive terminal along the second direction is as close to the thermal management component as possible, so that the heat generated by the battery cell under normal working conditions can also be better dissipated through the thermal management component via the surface arranged on the side of the outer shell away from the conductive terminal along the second direction, which is beneficial to improving the heat dissipation efficiency of the battery cell under normal working conditions.

[0040] In one embodiment, when projected along the first direction, a projection area of ​​the preset surface is located within a projection area of ​​the second insulating layer.

[0041] In the embodiment of the present application, the projection area of ​​the preset surface is located within the projection area of ​​the second insulating layer, so that the second insulating layer can completely cover the preset surface of the outer shell. When thermal runaway occurs in the battery cell, the second insulating layer can further limit the heat generated by the thermal runaway battery cell from being directly transferred to the adjacent battery cell, which is beneficial to further reduce the speed of heat transfer between adjacent battery cells.

[0042] In one embodiment, the second insulating layers are disposed on two opposite sides of the housing along the first direction, and the second insulating layers on the two sides are arranged at intervals.

[0043] In the embodiment of the present application, second insulating layers are provided on opposite sides of the outer shell along the first direction. The second insulating layers on both sides are arranged at intervals, which is beneficial for the second insulating layers to further limit the heat generated by the battery cells in thermal runaway from being directly transferred to adjacent battery cells, and is beneficial for further reducing the speed of heat transfer between adjacent battery cells.

[0044] In one embodiment, the first insulating layer is a waterproof insulating layer, which can prevent moisture from invading the housing, and the waterproof insulating layer is bonded to the second insulating layer.

[0045] In the embodiment of the present application, the waterproof insulating layer can prevent moisture from invading the outer shell, which helps to reduce the possibility of moisture invading the outer shell and causing a short circuit in the battery cell, and then helps to improve the safety of the battery cell.

[0046] In one embodiment, the second insulating layer is located between the outer shell and the first insulating layer.

[0047] In the embodiments of the present application, the second insulating layer is located between the outer shell and the first insulating layer, which is conducive to the second insulating layer restricting the heat generated by the battery cell in thermal runaway from directly transferring to the first insulating layer, and is conducive to reducing the possibility of the first insulating layer melting and perforating. The possibility of the first insulating layer not perforating is increased, which is conducive to inhibiting the second insulating layer from absorbing moisture, and then is conducive to reducing the possibility of moisture invading the outer shell and causing a short circuit of the battery cell, so as to improve the safety of the battery cell.

[0048] In one embodiment, the second insulating layer includes a plurality of sub-layers stacked in sequence along the thickness direction of the second insulating layer, and the thicknesses of the plurality of sub-layers are all less than or equal to 400 μm.

[0049] In the embodiments of the present application, the thicknesses of the plurality of sub-layers are all less than or equal to 400 μm, so that the sub-layers are softer in texture under the condition of having a certain strength, which is conducive to improving the convenience of arranging the second insulating layer on the outer shell.

[0050] In one embodiment, the thicknesses of the plurality of sub-layers are all less than or equal to 200 μm.

[0051] In the embodiments of the present application, the thicknesses of the plurality of sub-layers are all less than or equal to 200 μm, so that the sub-layers are softer in texture under the condition of having a certain strength, which is conducive to improving the convenience of arranging the second insulating layer on the outer shell.

[0052] In one embodiment, the shape of the outer shell is square.

[0053] In the embodiments of the present application, the square battery cell is conducive to the closer arrangement between adjacent battery cells, which is conducive to improving the energy density of the battery device.

[0054] In the second aspect of the embodiments of the present application, a battery device is provided, including:

[0055] The battery cell according to any one of the foregoing embodiments;

[0056] A box body, and the battery cell is located in the box body.

[0057] In one embodiment, the second insulating layer corresponding to the battery cell adjacent to the box body is at least partially located between the box body and the corresponding outer shell.

[0058] In an embodiment of the present application, the second insulating layer corresponding to the battery cell adjacent to the box body is at least partially located between the box body and the corresponding outer shell, so as to reduce the possibility of the box body insulation failure caused by the conduction between the battery cell and the box body, and then is beneficial to reducing the possibility of constructing a high-voltage sparking circuit due to the box body, and is beneficial to improving the safety of the battery device.

[0059] In one embodiment, among two adjacent battery cells, the second insulating layer of at least one of the battery cells is located between the outer shells of the corresponding two adjacent battery cells.

[0060] In an embodiment of the present application, the second insulating layer of at least one battery cell is located between the outer shells of the corresponding two adjacent battery cells, so that there is at least one second insulating layer between the outer shells of the two adjacent battery cells, which is beneficial to reducing the possibility of thermal diffusion of the battery cells.

[0061] In one embodiment, the battery device further includes a mounting rack connected in the box body, the battery cell is mounted on the mounting rack, and the second insulating layer corresponding to the battery cell adjacent to the mounting rack is at least partially located between the mounting rack and the corresponding outer shell.

[0062] In an embodiment of the present application, the second insulating layer corresponding to the battery cell adjacent to the mounting rack is at least partially located between the mounting rack and the corresponding outer shell, so as to reduce the possibility of the mounting rack insulation failure caused by the conduction between the battery cell and the mounting rack, and then is beneficial to reducing the possibility of constructing a high-voltage sparking circuit due to the mounting rack, and is beneficial to improving the safety of the battery.

[0063] In a third aspect of the embodiments of the present application, there is provided an electrical device, including:

[0064] The battery device according to any one of the foregoing embodiments;

[0065] An electrical power consuming entity, the battery device is arranged on the electrical power consuming entity, and the battery device supplies power to the electrical power consuming entity.

[0066] In a fourth aspect of the embodiments of the present application, there is provided an energy storage device, including:

[0067] The battery device according to any one of the foregoing embodiments, and the battery device can store electric power;

[0068] A mounting box, and the battery device is arranged in the mounting box.

[0069] Invention effects

[0070] In the battery cell provided in the embodiment of the present application, the second insulating layer is arranged on the first insulating layer, and the second insulating layer is located on the side of the shell away from the electrode assembly, so that the second insulating layer can be located between the shells of two adjacent battery cells. When the battery cell has thermal runaway, the second insulating layer with better heat resistance is not easily damaged under the high temperature generated by the thermal runaway battery cell. The second insulating layer can limit the heat generated by the thermal runaway battery cell to be directly transferred to the adjacent battery cell, which is conducive to reducing the speed of heat transfer between adjacent battery cells. Furthermore, the second insulating layer that is not easily damaged under the high temperature generated by the thermal runaway battery cell is conducive to reducing the possibility of direct contact between the shells of adjacent battery cells, and then it is conducive to reducing the possibility of overlapping short circuits between the shells of adjacent battery cells, causing high-voltage ignition and breakdown. Therefore, when the battery cell has thermal runaway, the second insulating layer is arranged between the shells of adjacent battery cells, which is conducive to reducing the possibility of thermal runaway spreading between adjacent battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is a schematic diagram of the assembly of the housing and the second insulating layer in one embodiment of the present application;

[0072] Figure 2 This is a schematic diagram of the assembly of the housing and the second insulating layer in another embodiment of the present application;

[0073] Figure 3 This is a schematic diagram of the assembly of the housing and the second insulating layer in another embodiment of the present application;

[0074] Figure 4 This is a schematic diagram of the assembly of the housing and the second insulating layer in another embodiment of the present application;

[0075] Figure 5 for Figure 4 Schematic diagram of the assembly of the middle shell, the first insulating layer and the second insulating layer;

[0076] Figure 6 Schematic diagram of the assembly sequence of the first insulating layer and the second insulating layer in one embodiment of the present application.

[0077] Description of Reference Numerals

[0078] 1. Battery cell; 11. Shell; 11a. Preset surface; 12. Conductive terminal; 13. First insulating layer; 14. Second insulating layer; 14a. Accommodating cavity; 14b. Opening; 141. Main membrane; 142. First sub-membrane; 143. Second sub-membrane; 143a. Avoidance cavity; 15. Adhesive layer. DETAILED DESCRIPTION

[0079] The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the embodiments of this application are intended to cover non-exclusive inclusion.

[0081] In the description of the embodiments of this application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0082] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0083] In the description of the embodiments of this application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0084] In the description of the embodiments of this application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0085] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, which can be direct contact or contact through an intermediate medium layer. It can be contact with substantially no interaction force between the two contacting objects, or contact with interaction force between the two contacting objects.

[0086] As part of the creative concept of the present application, before describing the embodiments of the present application, it is necessary to analyze the reasons for the possible thermal diffusion between adjacent battery cells to a certain extent in the related art, and obtain the technical solutions of the embodiments of the present application through reasonable analysis.

[0087] In the related art, when a battery cell in a battery device undergoes thermal runaway, the temperature of the outer shell of the battery cell is relatively high. The relatively high temperature easily causes the first insulating layer disposed outside the outer shell to melt, which may cause the outer shells of two adjacent battery cells to come into direct contact. On the one hand, when the outer shells of two adjacent battery cells are in direct contact, the heat generated by one of the battery cells that has undergone thermal runaway can be directly transferred to the outer shell of the adjacent battery cell, which may cause the adjacent battery cell to rapidly heat up. When the temperature of the adjacent battery cell reaches its own heat resistance threshold, it may cause the adjacent battery cell to undergo thermal runaway, and then cause the thermal runaway to spread within the battery device. On the other hand, for the case where two adjacent battery cells are connected in series, the melting of the first insulating layer may cause the outer shells of the two adjacent battery cells to come into direct contact, which may cause a short circuit at the contact position between the outer shells of the two adjacent battery cells, inducing high-voltage spark breakdown, further accelerating the heat transfer between the adjacent battery cells, and increasing the possibility of thermal runaway spreading within the battery device.

[0088] If an insulating layer with better temperature tolerance can be added between the outer shells of two adjacent battery cells, and still be able to separate the outer shells of the two adjacent battery cells in the case of the melting of the first insulating layer, the possibility of thermal diffusion between adjacent battery cells can be effectively reduced. Therefore, for the battery cell of the embodiment of the present application, by providing a second insulating layer with better heat resistance than the first insulating layer on the outer shell of the battery cell, in the case where the battery cell undergoes thermal runaway and the first insulating layer melts, the second insulating layer can isolate the outside of the outer shell of the battery cell, thereby separating the outer shells of two adjacent battery cells, slowing down the speed of heat transfer to the adjacent battery cell, and also reducing the possibility of short-circuit connection between the outer shells of two adjacent battery cells, and then being beneficial to reducing the possibility of thermal runaway spreading within the battery device.

[0089] The solution of the embodiment of the present application can be but is not limited to being applied to battery cell 1, a battery device including battery cell 1, an electrical device including the battery device, or an energy storage device including the battery device.

[0090] An embodiment of the present application provides an energy storage device, including a battery device and an installation box. The battery device is disposed in the installation box, and the battery device can store electricity.

[0091] The energy storage device can be, but is not limited to, applied to energy storage containers, energy storage cabinets, etc.

[0092] An embodiment of the present application provides an electrical device, including an electrical main body and a battery device. The battery device is disposed in the electrical main body, and the battery device provides power for the electrical main body.

[0093] The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, and an electric aircraft toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, and a spaceship, etc.

[0094] In the following embodiments, for the convenience of description, the electrical device in an embodiment of the present application is taken as an example of a vehicle for illustration. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc. The battery device is disposed inside the vehicle. The battery device can be disposed at the bottom, the head, or the tail of the vehicle. The battery device can be used for the power supply of the vehicle. For example, the battery device can be used as the operating power source of the vehicle. The vehicle can include an electrical main body, and the electrical main body includes a controller and a motor. The controller is used to control the battery device to supply power to the motor. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle.

[0095] In an embodiment of the present application, the battery device can not only be used as the operating power source of the vehicle, but also be used as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0096] An embodiment of the present application provides a battery device, including a battery cell 1 and a box body. The battery cell 1 is located inside the box body.

[0097] As an example, the box body can include a first box body and a second box body. The first box body and the second box body are buckled, so that a closed space is formed inside the box body to accommodate the battery cell 1. Here, "closed" means covering or closing, which can be sealed or non-sealed. The first box body can be a top cover or a bottom plate.

[0098] As an example, the box body can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell 1.

[0099] As an example, the box body can be part of the chassis structure of a vehicle. For example, the top cover of the box body can become at least part of the floor of the vehicle, or the frame of the box body can become at least part of the cross beams and longitudinal beams of the vehicle.

[0100] The battery cell 1 includes a housing 11 and an electrode assembly. The electrode assembly includes positive and negative electrode plates and a separator. The housing 11 can be a sealed structure or a non-sealed structure. As an example, the housing 11 is a non-sealed structure. The housing 11 functions to protect the electrode assembly. The battery cell 1 further includes a sealing bag located between the housing 11 and the electrode assembly, and the sealing bag is used to encapsulate the electrode assembly. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0101] For the battery cell 1 according to the embodiment of the present application, please refer to Figures 1 to 5 , the battery cell 1 includes a housing 11, an electrode assembly, a conductive terminal 12, a first insulating layer 13, and a second insulating layer 14. The electrode assembly is located inside the housing 11. The conductive terminal 12 is installed on the housing 11, and the conductive terminal 12 is electrically connected to the electrode assembly. The first insulating layer 13 covers the housing 11 to insulate the outer surface of the housing 11. The housing 11 is located inside the first insulating layer 13. The second insulating layer 14 is provided on the first insulating layer 13. The second insulating layer 14 is located on the side of the housing 11 away from the electrode assembly, and the heat resistance of the second insulating layer 14 is greater than that of the first insulating layer 13.

[0102] Exemplarily, the range in which the first insulating layer 13 covers the housing 11 is not limited.

[0103] Exemplarily, the first insulating layer 13 covers the remaining surfaces of the housing 11 except for the surface where the conductive terminal 12 is located.

[0104] It should be noted that the second insulating layer 14 is located on the side of the housing 11 away from the electrode assembly. It can be that the second insulating layer 14 is only provided between the housings 11 of two adjacent battery cells 1, or the second insulating layer 14 is provided both between the housings 11 of two adjacent battery cells 1 and in the part outside the space between the housings 11 of two adjacent battery cells 1.

[0105] Exemplarily, when the second insulating layer 14 is provided between the housings 11 of two adjacent battery cells 1, it can be that only one layer of the second insulating layer 14 is provided between the housings 11 of the two battery cells 1, or the second insulating layer 14 is provided on both of the housings 11 of the two battery cells 1, so that two layers of the second insulating layer 14 are provided between the housings 11 of two adjacent battery cells 1.

[0106] Exemplarily, please refer to Figure 1, the second insulating layer 14 covers the remaining surfaces of the outer shell 11 of any battery cell 1 except for the surface where the conductive terminal 12 is located, so that there are two layers of the second insulating layer 14 between the outer shells 11 of two adjacent battery cells 1.

[0107] Exemplarily, there is one layer of the second insulating layer 14 between the outer shells 11 of two adjacent battery cells 1.

[0108] Exemplarily, there is one layer of the second insulating layer 14 between the outer shells 11 of two adjacent battery cells 1. When one of the battery cells 1 has a thermal runaway, the temperature of the outer shell 11 of the battery cell 1 is relatively high, the first insulating layer 13 is melted and perforated. The second insulating layer 14 can separate the outer shells 11 of two adjacent battery cells 1 to reduce the possibility of the thermal runaway spreading between adjacent battery cells 1.

[0109] It should be explained that the heat resistance of the second insulating layer 14 is greater than that of the first insulating layer 13. It can be that both the first insulating layer 13 and the second insulating layer 14 are in the same temperature environment. As the temperature rises, the first insulating layer 13 perforates earlier than the second insulating layer 14. It can also be that the first insulating layer 13 and the second insulating layer 14 are in different temperature environments respectively. The first insulating layer 13 is kept in a preset time in a certain temperature environment. If the first insulating layer 13 does not perforate, a new first insulating layer 13 is replaced and kept in a higher temperature environment for the preset time until the first insulating layer 13 perforates and the temperature corresponding to when the first insulating layer 13 perforates is recorded as the first temperature. The second insulating layer 14 is kept in a preset time in a certain temperature environment. In each temperature environment, the time kept by the first insulating layer 13 and the second insulating layer 14 is equal. If the second insulating layer 14 does not perforate, a new second insulating layer 14 is replaced and kept in a higher temperature environment for the preset time until the second insulating layer 14 perforates and the temperature corresponding to when the second insulating layer 14 perforates is recorded as the second temperature, and the second temperature is greater than the first temperature.

[0110] Exemplarily, both the first insulating layer 13 and the second insulating layer 14 are in the same temperature environment. As the temperature rises, when the temperature of the environment where the first insulating layer 13 and the second insulating layer 14 are located is 180 °C and the preset time is 20 minutes, the first insulating layer 13 perforates and the second insulating layer 14 does not perforate, that is, it is considered that the heat resistance of the second insulating layer 14 is greater than that of the first insulating layer 13.

[0111] Exemplarily, the second insulating layer 14 is disposed on the first insulating layer 14, and the second insulating layer 14 is located on the side of the outer shell 11 away from the electrode assembly. It can be that the second insulating layer 14 is located between the first insulating layer 13 and the outer shell 11, or the first insulating layer 13 is located between the second insulating layer 14 and the outer shell 11.

[0112] In an embodiment of the present application, the second insulating layer 14 is disposed on the first insulating layer 13. The second insulating layer 14 is located on the side of the outer shell 11 away from the electrode assembly, so that the second insulating layer 14 can be located between the outer shells 11 of two adjacent battery cells 1. When a battery cell 1 undergoes thermal runaway, the second insulating layer 14 with better heat resistance to temperature is not easily damaged under the high temperature generated by the thermally runaway battery cell 1. The second insulating layer 14 can limit the heat generated by the thermally runaway battery cell 1 from directly transferring to the adjacent battery cell 1, which is beneficial to reducing the heat transfer speed between adjacent battery cells 1. Further, the second insulating layer 14 that is not easily damaged under the high temperature generated by the thermally runaway battery cell 1 is beneficial to reducing the possibility of direct contact between the outer shells 11 of adjacent battery cells 1, and then is beneficial to reducing the possibility of lap short circuit between the outer shells 11 of adjacent battery cells 1, resulting in high-voltage spark breakdown. Therefore, when a battery cell 1 undergoes thermal runaway, arranging the second insulating layer 14 between the outer shells 11 of adjacent battery cells 1 is beneficial to reducing the possibility of thermal runaway spreading between adjacent battery cells 1.

[0113] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 320 Wh / L and less than 390 Wh / L, and the heat resistance temperature range of the second insulating layer 14 is 180°C ≤ T ≤ 450°C.

[0114] It should be noted that the heat resistance temperature refers to the temperature at which a material perforates after experiencing a preset time under the action of high temperature.

[0115] Exemplarily, the first insulating layer 13 is heated at a constant rate using a DSC (Differential Scanning Calorimeter) to obtain the heat-temperature curve of the first insulating layer 13. Among them, heat is the abscissa and temperature is the ordinate. The heat resistance temperature of the first insulating layer 13 can be obtained by extracting the temperature peak value in the heat-temperature curve. The second insulating layer 14 is heated at a constant rate using a differential scanning calorimeter to obtain the heat-temperature curve of the second insulating layer 14. Among them, heat is the abscissa and temperature is the ordinate. The heat resistance temperature of the second insulating layer 14 can be obtained by extracting the temperature peak value in the heat-temperature curve, and the heat resistance temperature of the second insulating layer 14 is greater than that of the first insulating layer 13.

[0116] Exemplarily, within the temperature range of 180°C to 450°C, the second insulating layer 14 can not perforate within 20 minutes.

[0117] Exemplarily, the heat resistance temperature of the second insulating layer 14 can be 180°C, 190°C, 300°C, 350°C, 400°C or 450°C.

[0118] Exemplarily, the second insulating layer 14 can withstand a temperature of 400 °C for 20 minutes without perforation.

[0119] Exemplarily, the energy density of the battery cell 1 can be 320 Wh / L, 330 Wh / L, 340 Wh / L, 350 Wh / L, 360 Wh / L, 370 Wh / L, 380 Wh / L, or 390 Wh / L.

[0120] It should be noted that the unit of energy density is Wh / L (watt-hour per liter), and the unit of heat-resistant temperature is °C (Celsius).

[0121] In the embodiments of the present application, when the energy density of the battery cell 1 ranges from 320 Wh / L to 390 Wh / L, the required heat-resistant temperature of the second insulating layer 14 ranges from 180 °C to 450 °C. The second insulating layer 14 has a relatively high heat-resistant temperature, which reduces the possibility of the second insulating layer 14 melting and perforating during thermal runaway of the battery cell 1, and is beneficial to restricting the heat generated by the thermally runaway battery cell 1 from directly transferring to the outer shell 11 of the adjacent battery cell 1, thereby reducing the possibility of thermal runaway spread between adjacent battery cells 1.

[0122] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 390 Wh / L and less than 490 Wh / L, and the heat-resistant temperature of the second insulating layer 14 ranges from 220 °C ≤ T ≤ 450 °C.

[0123] Exemplarily, within the temperature range of 180 °C to 450 °C, the second insulating layer 14 can withstand a temperature for 20 minutes without perforation.

[0124] Exemplarily, the heat-resistant temperature of the second insulating layer 14 can be 220 °C, 250 °C, 300 °C, 350 °C, 400 °C, or 450 °C.

[0125] Exemplarily, the second insulating layer 14 can withstand a temperature of 450 °C for 20 minutes without perforation.

[0126] Exemplarily, the energy density of the battery cell 1 can be 390 Wh / L, 400 Wh / L, 410 Wh / L, 420 Wh / L, 430 Wh / L, 440 Wh / L, 450 Wh / L, 460 Wh / L, 470 Wh / L, 480 Wh / L, or 490 Wh / L.

[0127] In an embodiment of the present application, when the energy density of the battery cell 1 ranges from 390 Wh / L to 490 Wh / L, the required heat-resistant temperature of the second insulating layer 14 ranges from 220 °C to 450 °C. The second insulating layer 14 has a relatively high heat-resistant temperature, so as to reduce the possibility of melting and perforation of the second insulating layer 14 during the thermal runaway of the battery cell 1, which is beneficial to restricting the heat generated by the battery cell 1 in thermal runaway from directly transferring to the outer shell 11 of the adjacent battery cell 1, and then beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells 1.

[0128] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 490 Wh / L and less than 550 Wh / L, and the heat-resistant temperature range of the second insulating layer 14 is 250 °C ≤ T ≤ 450 °C.

[0129] Exemplarily, within the temperature range of 250 °C to 450 °C, the second insulating layer 14 can not be perforated within 20 minutes.

[0130] Exemplarily, the heat-resistant temperature of the second insulating layer 14 can be 250 °C, 270 °C, 300 °C, 350 °C, 400 °C or 450 °C.

[0131] Exemplarily, the second insulating layer 14 can not be perforated within 20 minutes under the condition of 350 °C.

[0132] Exemplarily, the energy density of the battery cell 1 can be 490 Wh / L, 500 Wh / L, 510 Wh / L, 520 Wh / L, 530 Wh / L, 540 Wh / L or 550 Wh / L.

[0133] In an embodiment of the present application, when the energy density of the battery cell 1 ranges from 490 Wh / L to 550 Wh / L, the required heat-resistant temperature of the second insulating layer 14 ranges from 250 °C to 450 °C. The second insulating layer 14 has a relatively high heat-resistant temperature, so as to reduce the possibility of melting and perforation of the second insulating layer 14 during the thermal runaway of the battery cell 1, which is beneficial to restricting the heat generated by the battery cell 1 in thermal runaway from directly transferring to the outer shell 11 of the adjacent battery cell 1, and then beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells 1.

[0134] In one embodiment, the ratio of the energy density of the battery cell 1 to the heat-resistant temperature of the second insulating layer 14 ranges from 0.84 Wh / L / °C to 1.96 Wh / L / °C.

[0135] Exemplarily, the range of the ratio of the energy density of the battery cell 1 to the heat-resistant temperature of the second insulating layer 14 can be expressed as:

[0136] 0.84 Wh / L / ℃ ≤ E / T ≤ 1.96 Wh / L / ℃, where E represents the energy density of battery cell 1, and T represents the heat resistance temperature of the second insulating layer 14.

[0137] The calculation formula for the energy density E of battery cell 1 can be: the capacity of battery cell 1 * the rated voltage of battery cell 1 / the volume of battery cell 1.

[0138] The capacity of battery cell 1 can be measured by a battery capacity tester, the rated voltage of battery cell 1 can be measured by a voltmeter, the volume of battery cell 1 can be calculated by measuring the length, width, and height of battery cell 1 with a vernier caliper and then using the volume calculation formula, and the heat resistance temperature T of the second insulating layer 14 can be measured by a thermometer.

[0139] It should be noted that the unit of the ratio of the energy density of battery cell 1 to the heat resistance temperature of the second insulating layer 14 is Wh / L / ℃ (watt-hour / liter / degree Celsius).

[0140] It should be noted that when the energy density of battery cell 1 increases, when battery cell 1 undergoes thermal runaway, the heat generated per unit volume of battery cell 1 is also higher, making the thermal runaway of battery cell 1 more severe.

[0141] It should be noted that when the heat resistance temperature of the material used for the second insulating layer 14 increases, the price of the material used for the second insulating layer 14 will also increase.

[0142] Exemplarily, under different ratios of the energy density of battery cell 1 to the heat resistance temperature of the second insulating layer 14, the melting loss situation of the second insulating layer 14 is shown in the following table:

[0143] E (Wh / L) T(℃) E / T Insulation damage condition Thickness retention rate before and after testing Example 1 320 180 1.78 Slight local shrinkage 57％ Example 2 320 310 1.03 Normal 98％ Example 3 320 380 0.84 Normal 100％ Example 4 390 220 1.77 Slight local shrinkage 63％ Example 5 390 310 1.26 Normal 83％ Example 6 390 380 1.03 Normal 99％ Example 7 490 250 1.96 Slight local shrinkage 53％ Example 8 490 310 1.58 Normal 78％ Example 9 490 380 1.29 Normal 95％ Example 10 550 290 1.90 Slight local shrinkage 60％ Example 11 550 310 1.45 Normal 87％ Example 12 550 450 1.22 Normal 98％ Comparative Example 1 550 190 2.89 Significant melting damage 17％ Comparative Example 2 550 210 2.62 Melting damage 28％ Comparative Example 3 320 450 0.71 Normal 100％

[0144] Exemplarily, compared with Example 3, in Example 2, the second insulating layer 14 has basically no melting loss. Therefore, the material with a heat resistance temperature of 310 °C in Example 2 is preferably selected for the second insulating layer 14 to improve the cost performance of the material used for the second insulating layer 14.

[0145] It should be explained that in Example 7, there is a slight local shrinkage phenomenon in the second insulating layer 14. The second insulating layer 14 shrinks locally, but does not perforate. In this case, the second insulating layer 14 does not melt and can still play a good insulating role.

[0146] In the embodiments of the present application, the ratio of the energy density of the battery cell 1 to the heat resistance temperature of the second insulating layer 14 is limited within a relatively reasonable range. When the energy density of the battery cell 1 is relatively large, there is a minimum value for the heat resistance temperature of the second insulating layer 14 to reduce the possibility of the second insulating layer 14 suffering from melting damage. When the energy density of the battery cell 1 is relatively small, there is a maximum value for the heat resistance temperature of the second insulating layer 14. In the case where the possibility of the second insulating layer 14 suffering from melting damage is relatively small, it is to reduce the cost loss caused by using overly excellent materials for the second insulating layer 14, thereby improving the cost performance of the materials used for the second insulating layer 14.

[0147] In one embodiment, the range of the ratio of the energy density of the battery cell 1 to the heat resistance temperature of the second insulating layer 14 is 1.03 Wh / L / °C to 1.58 Wh / L / °C.

[0148] In the embodiments of the present application, the ratio of the energy density of the battery cell 1 to the heat resistance temperature of the second insulating layer 14 is limited within a more reasonable range. In the case where the possibility of the second insulating layer 14 suffering from melting damage is relatively small, it further reduces the cost loss caused by using overly excellent materials for the second insulating layer 14, thereby being conducive to further improving the cost performance of the materials used for the second insulating layer 14.

[0149] In one embodiment, the material of the first insulating layer 13 is polyethylene terephthalate or polycarbonate, and the material of the second insulating layer 14 is polypropylene, polyethylene, polyamide, polyethylene terephthalate, polyphthalamide, polyphenylene sulfide or polyimide.

[0150] In the embodiments of the present application, the material of the first insulating layer 13 is polyethylene terephthalate or polycarbonate, which has good physical and mechanical properties, insulation properties and waterproof properties, and is conducive to improving the safety of the battery cell 1. The material of the second insulating layer 14 is polypropylene, polyethylene, polyamide, polyethylene terephthalate, polyphthalamide, polyphenylene sulfide or polyimide. Polyimide has good temperature tolerance performance, which is conducive to the second insulating layer 14 restricting the heat generated by the battery cell 1 with thermal runaway from directly transferring to adjacent battery cells 1, and is conducive to reducing the heat transfer speed between adjacent battery cells 1.

[0151] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 320 Wh / L, the energy density of the battery cell 1 is less than 390 Wh / L, and the thickness of the second insulating layer 14 is 50 μm to 700 μm.

[0152] It should be noted that the unit of the thickness is μm (micrometer).

[0153] Exemplarily, the thickness of the second insulating layer 14 may be 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm or 700 μm.

[0154] In the embodiment of the present application, when the energy density of the battery cell 1 ranges from 320 Wh / L to 390 Wh / L, the required thickness of the second insulating layer 14 ranges from 50 μm to 700 μm. The relatively thick second insulating layer 14 is beneficial to reducing the possibility of melting and perforation of the second insulating layer 14 during the thermal runaway of the battery cell 1, and is beneficial to restricting the heat generated by the battery cell 1 in thermal runaway from directly transferring to the adjacent battery cell 1, thereby being beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells 1; on the other hand, the second insulating layer 14 with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film during the normal use of the battery cell 1.

[0155] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 390 Wh / L and less than 490 Wh / L, and the thickness of the second insulating layer 14 is 70 μm to 700 μm.

[0156] Exemplarily, the thickness of the second insulating layer 14 may be 70 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm or 700 μm.

[0157] In the embodiment of the present application, when the energy density of the battery cell 1 ranges from 390 Wh / L to 490 Wh / L, the required thickness of the second insulating layer 14 ranges from 70 μm to 700 μm. The relatively thick second insulating layer 14 is beneficial to reducing the possibility of melting and perforation of the second insulating layer 14 during the thermal runaway of the battery cell 1, and is beneficial to restricting the heat generated by the battery cell 1 in thermal runaway from directly transferring to the adjacent battery cell 1, thereby being beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells 1; on the other hand, the second insulating layer 14 with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film during the normal use of the battery cell 1.

[0158] In one embodiment, the energy density of the battery cell 1 is greater than or equal to 490 Wh / L and less than 550 Wh / L, and the thickness of the second insulating layer 14 is 100 μm to 700 μm.

[0159] Exemplarily, the thickness of the second insulating layer 14 may be 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm or 700μm.

[0160] In the embodiments of the present application, when the energy density range of the battery cell 1 is 490 Wh / L to 550 Wh / L, the required thickness range of the second insulating layer 14 is 100μm to 700μm. The relatively thick second insulating layer 14 is beneficial to reducing the possibility of melting and perforation of the second insulating layer 14 during thermal runaway of the battery cell 1, and is beneficial to restricting the heat generated by the battery cell 1 in thermal runaway from directly transferring to adjacent battery cells 1, thereby being beneficial to reducing the possibility of thermal runaway diffusion between adjacent battery cells 1; on the other hand, the second insulating layer 14 with a certain thickness has a certain strength, which is beneficial to reducing the possibility of mechanical damage to the second insulating film during the normal use of the battery cell 1.

[0161] In one embodiment, the range of the ratio of the energy density of the battery cell 1 to the thickness of the second insulating layer 14 is 0.8 Wh / L / μm to 6.4 Wh / L / μm.

[0162] Wherein, E represents the energy density of the battery cell 1, and D represents the thickness of the second insulating layer 14.

[0163] The calculation formula for the energy density E of the battery cell 1 can be: the capacity of the battery cell 1 * the rated voltage of the battery cell 1 / the volume of the battery cell 1.

[0164] The capacity of the battery cell 1 can be measured by a battery capacity tester, the rated voltage of the battery cell 1 can be measured by a voltmeter, the volume of the battery cell 1 can be calculated by measuring the length, width and height of the battery cell 1 with a vernier caliper and then using the volume calculation formula, and the thickness D of the second insulating layer 14 can be measured by a vernier caliper.

[0165] The unit of the ratio of the energy density of the battery cell 1 to the thickness of the second insulating layer 14 is Wh / L / um (watt-hour / liter / micron).

[0166] It should be noted that as the thickness of the material used for the second insulating layer 14 increases, the price of the material used for the second insulating layer 14 will also increase.

[0167] Exemplarily, under different ratios of the energy density of the battery cell 1 to the thickness of the second insulating layer 14, the melting and damage conditions of the second insulating layer 14 are shown in the following table:

[0168] E (Wh / L) D (μm) E / D Thermal diffusion test Example 1 320 50 6.4 Normal Example 2 320 100 3.2 Normal Example 3 390 70 5.6 Adjacent battery cells open the valve Example 4 390 200 2.0 Normal Example 5 490 100 4.9 Adjacent battery cells open the valve Example 6 490 300 1.6 Normal Example 7 550 150 3.7 Adjacent battery cells open the valve Example 8 550 700 0.8 Normal Comparative Example 1 550 100 5.5 Diffusion

[0169] It should be noted that the opening of adjacent battery cells refers to the opening of the explosion-proof valve of battery cell 1. The explosion-proof valve of battery cell 1 has been opened, but battery cell 1 has not yet experienced thermal runaway, which is a barely acceptable state. Diffusion means that the thermal runaway of battery cell 1 spreads, causing thermal runaway of adjacent battery cells 1.

[0170] In an embodiment of the present application, the ratio of the energy density of battery cell 1 to the thickness of the second insulating layer 14 is limited within a relatively reasonable range. When the energy density of battery cell 1 is large, there is a minimum value for the thickness of the second insulating layer 14 to reduce the possibility of perforation and melting damage of the second insulating layer 14. When the energy density of battery cell 1 is small, there is a maximum value for the thickness of the second insulating layer 14. In the case where the possibility of melting damage of the second insulating layer 14 is small, the cost and the loss of the internal space of the battery device caused by using overly excellent materials for the second insulating layer 14 are reduced, thereby improving the cost performance of the materials used for the second insulating layer 14 and the utilization rate of the internal space of the battery device.

[0171] In one embodiment, the range of the ratio of the energy density of battery cell 1 to the thickness of the second insulating layer 14 is 0.8 Wh / L / μm to 3.7 Wh / L / μm.

[0172] In an embodiment of the present application, the ratio of the energy density of battery cell 1 to the thickness of the second insulating layer 14 is limited within a more reasonable range. In the case where the possibility of melting damage of the second insulating layer 14 is small, the cost and the loss of the internal space of the battery device caused by using overly excellent materials for the second insulating layer 14 are further reduced, thereby facilitating further improvement of the cost performance of the materials used for the second insulating layer 14 and the utilization rate of the internal space of the battery device.

[0173] In one embodiment, please refer to Figure 4 and Figure 5 , the largest outer surface of the housing 11 is the preset surface 11a, the direction perpendicular to the preset surface 11a is the first direction, and the second insulating layer 14 is at least partially located on at least one side of the housing 11 along the first direction.

[0174] Exemplarily, Figure 1 、 Figures 3 to 5 the direction shown by R1 in

[0175] It should be explained that the second insulating layer 14 being at least partially located on at least one side of the housing 11 along the first direction can mean that the second insulating layer 14 can be only provided on the preset surface 11a of the cell body, or can straddle other surfaces.

[0176] Exemplarily, please refer to Figure 4 and Figure 5, the second insulating layer 14 is at least partially located on opposite sides of the housing 11 along the first direction.

[0177] It should be noted that the areas of the remaining sides and the bottom surface of the battery cell body are relatively small. When the battery cell 1 undergoes thermal runaway, the temperatures of the other surfaces of the housing 11 of the battery cell 1 except the preset surface 11a are relatively low. The first insulating layer 13 covering the remaining surfaces of the housing 11 of the battery cell 1 except the surface where the conductive terminal 12 is located and the preset surface 11a can also not undergo perforation and melting damage, thereby keeping the surface on the side of the housing 11 of the battery cell 1 facing away from the conductive terminal 12 and the remaining sides of the housing 11 of the battery cell 1 except the preset surface 11a insulated.

[0178] Exemplarily, please refer to Figure 4 and Figure 5 , along the first direction, the projection area of the preset surface 11a is located within the projection area of the second insulating layer 14.

[0179] Exemplarily, please refer to Figure 5 , along the first direction, the first insulating layer 13 is located on the side of the second insulating layer 14 close to the housing 11. The first insulating layer 13 covers the remaining surfaces of the housing 11 except the surface where the conductive terminal 12 is located. The second insulating layer 14 is arranged on the outer side of the first insulating layer 13, and the second insulating layer 14 does not straddle the other surfaces of the housing 11 except the preset surface 11a.

[0180] Exemplarily, along the first direction, the second insulating layer 14 is located on the side of the first insulating layer 13 close to the corresponding housing 11. The second insulating layer 14 is arranged on the preset surface 11a of the housing 11, and the second insulating layer 14 does not straddle the other surfaces of the housing 11 except the preset surface 11a.

[0181] Exemplarily, the second insulating layer 14 is located between the housings 11 of two adjacent battery cells 1. It can be that only one second insulating layer 14 is located between the housings 11 of two adjacent battery cells 1, or the preset surfaces 11a of the housings 11 of two adjacent battery cells 1 are both provided with the second insulating layer 14, so that there are two second insulating layers 14 located between the housings 11 of two adjacent battery cells 1.

[0182] In the embodiments of the present application, when the battery cell 1 undergoes thermal runaway, the second insulating layer 14 can limit the heat generated by the battery cell 1 experiencing thermal runaway from directly transferring to the adjacent battery cell 1, which is beneficial to reducing the heat transfer rate between adjacent battery cells 1. The second insulating layer 14 is at least partially located on at least one side of the outer shell 11 along the first direction, and the second insulating layer 14 can cover the remaining surfaces of the battery cell body except for the preset surface 11a, which is beneficial to reducing the volume occupied by the second insulating layer 14, and then beneficial to improving the space utilization rate inside the battery device. The heat generated by the battery cell 1 under normal use conditions can be dissipated through the surface on the side of the outer shell 11 facing away from the conductive terminal 12, which is beneficial to improving the heat dissipation efficiency of the battery cell 1. The remaining side surfaces of the outer shell 11 except for the preset surface 11a are not covered by the second insulating layer 14, which is also beneficial to improving the bonding strength between the remaining side surfaces of the outer shell 11 except for the preset surface 11a and the remaining side surfaces of the outer shell 11 of the adjacent battery cell 1.

[0183] In one embodiment, please refer to Figure 2 , the shape of the second insulating layer 14 is annular, the second insulating layer 14 encloses a receiving cavity 14a and an opening 14b communicating with the receiving cavity 14a, openings 14b are provided on both opposite sides of the receiving cavity 14a, and the outer shell 11 is located in the receiving cavity 14a corresponding to the second insulating layer 14.

[0184] It should be noted that, please refer to Figures 1 to 5 , when the battery cell 1 undergoes thermal runaway, compared with the temperature of the preset surface 11a, the temperature of the other surfaces of the outer shell 11 except for the preset surface 11a is lower.

[0185] Exemplarily, please refer to Figure 2 , along the first direction, the projection area of the preset surface 11a is located within the projection area of the annular second insulating layer 14, and along the direction perpendicular to the smaller side surface of the outer shell 11, the projection area of the smaller side surface of the outer shell 11 is located within the projection area of the annular second insulating layer 14.

[0186] Exemplarily, along the first direction, the first insulating layer 13 is located on the side of the second insulating layer 14 close to the outer shell 11, the first insulating layer 13 covers the remaining surfaces of the outer shell 11 except for the surface where the conductive terminal 12 is located, and the outer shell 11 is located in the receiving cavity 14a corresponding to the annular second insulating layer 14.

[0187] Exemplarily, along the first direction, the second insulating layer 14 is located on the side of the first insulating layer 13 close to the corresponding outer shell 11, and the outer shell 11 is located in the receiving cavity 14a corresponding to the annular second insulating layer 14.

[0188] Exemplarily, the battery device further includes a heat management component, which is disposed in the opening 14b on the side away from the conductive terminal 12 and in contact with the battery cell 1. The heat management component can improve the heat dissipation efficiency of the battery cell 1 under normal use.

[0189] In the embodiment of the present application, when the battery cell 1 has thermal runaway, the second insulating layer 14 can limit the heat generated by the thermal runaway battery cell 1 from being directly transferred to the adjacent battery cell 1, which is beneficial to reducing the speed of heat transfer between adjacent battery cells. The two opposite sides of the accommodating cavity 14a enclosed by the annular second insulating layer 14 are provided with openings 14b, and the shell 11 is located in the accommodating cavity 14a, so that the second insulating layer 14 is arranged across the preset surface 11a of the shell 11 and the remaining side surfaces except the preset surface 11a of the shell 11, and the surface of the shell 11 on the side away from the conductive terminal 12 is not covered by the second insulating layer 14, and the heat generated by the battery cell 1 in normal use can be dissipated through the surface of the shell 11 on the side away from the conductive terminal 12, which is beneficial to improve the heat dissipation efficiency of the battery cell 1.

[0190] It is understandable that the second insulating layer 14 may be disposed discontinuously on the side of the housing 11. Exemplarily, the number of the second insulating layers 14 is four, and the four second insulating layers 14 are disposed on two preset surfaces 11a and the remaining two side surfaces of the housing 11, respectively, and the four second insulating layers 14 are spaced apart by a preset distance.

[0191] In one embodiment, please refer to Figure 3 The second insulating layer 14 includes a main film 141 and a first sub-film 142. The main films 141 are arranged on opposite sides of the shell 11 along the first direction. The first sub-film 142 is connected between the main films 141 on the corresponding sides. The arrangement direction of the conductive terminal 12 and the electrode assembly is the second direction. The second direction is arranged crosswise with the first direction. The first sub-film 142 is located on the side of the shell 11 away from the conductive terminal 12 along the second direction.

[0192] For example, Figure 1 , Figures 3 to 5 The direction indicated by R2 is the second direction.

[0193] For example, see Figure 3 Along the first direction, the projection area of ​​the preset surface 11a is located within the projection area of ​​the main film 141, and along the second direction, the projection area of ​​the surface of the housing 11 facing away from the conductive terminal 12 is located within the projection area of ​​the first sub-film 142, so that the second insulating layer 14 is U-shaped.

[0194] Exemplarily, along the first direction, the first insulating layer 13 is located on a side of the second insulating layer 14 close to the shell 11, and the first insulating layer 13 covers the remaining surface of the shell 11 except the surface where the conductive terminal 12 is located. The shell 11 is located in the space enclosed by the corresponding U-shaped second insulating layer 14.

[0195] Exemplarily, along the first direction, the second insulating layer 14 is located on a side of the first insulating layer 13 close to the corresponding outer shell 11 , and the outer shell 11 is located in a space enclosed by the corresponding U-shaped second insulating layer 14 .

[0196] In the embodiment of the present application, when the battery cell 1 has thermal runaway, the second insulating layer 14 can limit the heat generated by the battery cell 1 in thermal runaway to be directly transferred to the adjacent battery cell 1, which is beneficial to reduce the speed of heat transfer between adjacent battery cells 1. The main film 141 is arranged on the preset surface 11a, and the first sub-film 142 is located on the side of the shell 11 away from the conductive terminal 12 along the second direction, so that the second insulating layer 14 is arranged across the preset surface 11a of the shell 11 and the surface of the side of the shell 11 away from the conductive terminal 12, and the remaining side of the shell 11 except the preset surface 11a is not covered by the second insulating layer 14. The heat generated by the battery cell 1 in normal use can be dissipated through the remaining side of the shell 11 except the preset surface 11a, which is beneficial to improve the heat dissipation efficiency of the battery cell 1. The remaining side of the shell 11 except the preset surface 11a is not covered by the second insulating layer 14, which is also beneficial to improve the bonding strength between the remaining side of the shell 11 except the preset surface 11a and the remaining side of the adjacent shell 11 except the preset surface 11a.

[0197] It can be understood that the second insulating layer 14 may be discontinuously disposed on the preset surface 11a of the housing 11 and the surface of the housing 11 on the side away from the conductive terminal 12. Exemplarily, the number of the second insulating layers 14 is three, and the three second insulating layers 14 are respectively disposed on the two preset surfaces 11a and the surface of one side of the housing 11 away from the conductive terminal 12, and the three second insulating layers 14 are spaced apart by a preset distance.

[0198] In one embodiment, please refer to Figure 3 The second insulating layer 14 also includes a second sub-membrane 143. The second sub-membranes 143 are arranged on opposite sides of the shell 11 along the third direction. The third direction is arranged to cross the first direction and the second direction respectively. The first direction, the second direction and the third direction are not coplanar. The second sub-membrane 143 is respectively connected to the first sub-membrane 142 and the main membranes 141 on both sides. The second sub-membrane 143 on each side forms an avoidance cavity 143a, and the space enclosed by the main membrane 141, the first sub-membrane 142 and the second sub-membrane 143 is connected to the avoidance cavity 143a.

[0199] For example, Figure 1 , Figures 3 to 5The direction indicated by R3 is the third direction.

[0200] It should be explained that the third direction is arranged crosswise with the first direction and the second direction respectively, and the first direction, the second direction and the third direction are not coplanar, which means that the first direction and the second direction form a reference plane, and the third direction is arranged crosswise with the reference plane.

[0201] Exemplarily, the first direction, the second direction and the third direction are arranged perpendicular to each other, and the first direction, the second direction and the third direction are not coplanar.

[0202] For example, see Figure 3 Two second sub-membranes 143 are provided on any side of the shell 11 along the third direction, and the two second sub-membranes 143 are respectively connected to the first sub-membrane 142 and the corresponding main membranes 141 on both sides, and the two second sub-membranes 143 form an avoidance cavity 143a, and the space enclosed by the main membrane 141, the first sub-membrane 142 and the second sub-membrane 143 is connected to the avoidance cavity 143a, and the shell 11 is located in the space enclosed by the main membrane 141, the first sub-membrane 142 and the second sub-membrane 143.

[0203] In the embodiment of the present application, the second sub-membrane 143 is respectively connected to the first sub-membrane 142 and the main membrane 141 on both sides, so that the main membrane 141, the first sub-membrane 142 and the second sub-membrane 143 form a relatively stable constraint on the outer shell 11, which is conducive to fixing the outer shell 11 more firmly.

[0204] In one embodiment, please refer to Figure 3 , projected along the second direction, a projection area of ​​a surface of the housing 11 that is away from the conductive terminal 12 along the second direction is located within the projection area of ​​the first sub-film 142 .

[0205] For example, see Figure 3 The projection area of ​​the surface of the housing 11 along the second direction away from the conductive terminal 12 completely overlaps with the projection area of ​​the first sub-film 142 .

[0206] In the embodiment of the present application, the projection area of ​​the surface of the outer shell 11 along the second direction away from the conductive terminal 12 is located within the projection area of ​​the first sub-membrane 142, so that the first sub-membrane 142 can completely cover the surface of the outer shell 11 along the second direction away from the conductive terminal 12. When the battery cell 1 has thermal runaway, the first sub-membrane 142 with better temperature resistance can isolate the surface of the outer shell 11 along the second direction away from the conductive terminal 12, which is beneficial to reduce the possibility of heat diffusion between two adjacent battery cells 1.

[0207] It is understandable that the positional relationship between the projection area of ​​the surface of the housing 11 along the second direction away from the conductive terminal 12 and the projection area of ​​the first sub-film 142 is not limited. Exemplarily, the projection area of ​​the first sub-film 142 is located within the projection area of ​​the surface of the housing 11 along the second direction away from the conductive terminal 12.

[0208] In one embodiment, the thickness of the main film 141 is greater than the thickness of the first sub-film 142 .

[0209] In the embodiment of the present application, when thermal runaway occurs in the battery cell 1, the temperature of the preset surface 11a is generally greater than the temperature of the remaining surfaces of the outer shell 11 excluding the preset surface 11a, and the thickness of the main film 141 arranged on the preset surface 11a is greater than the thickness of the first sub-film 142 arranged on the surface of the outer shell 11 away from the conductive terminal 12 along the second direction. On the one hand, using different thicknesses of the second insulating layer 14 for different surfaces of the outer shell 11 is beneficial to reducing the production cost of the battery cell 1; on the other hand, the thicker main film 141 is beneficial to heat insulation between adjacent battery cells 1.

[0210] In one embodiment, the first sub-membrane 142 is located between the housing 11 and the thermal management component.

[0211] In the embodiment of the present application, the thinner first sub-membrane 142 is located between the outer shell 11 and the thermal management component, so that the surface arranged on the side of the outer shell 11 away from the conductive terminal 12 along the second direction is as close to the thermal management component as possible, so that the heat generated by the battery cell 1 under normal working conditions can also be better dissipated through the thermal management component through the surface arranged on the side of the outer shell 11 along the second direction away from the conductive terminal 12, which is beneficial to improving the heat dissipation efficiency of the battery cell 1 under normal working conditions.

[0212] In one embodiment, please refer to Figure 4 and Figure 5 , projected along the first direction, the projection area of ​​the preset surface 11 a is located within the projection area of ​​the second insulating layer 14 .

[0213] For example, see Figure 4 and Figure 5 , projected along the first direction, the projection area of ​​the preset surface 11a completely overlaps with the projection area of ​​the second insulating layer 14.

[0214] In the embodiment of the present application, the projection area of ​​the preset surface 11a is located within the projection area of ​​the second insulating layer 14, so that the second insulating layer 14 can completely cover the preset surface 11a of the outer shell 11. When the battery cell 1 has thermal runaway, the second insulating layer 14 can further limit the heat generated by the thermally runaway battery cell 1 from being directly transferred to the adjacent battery cell 1, which is beneficial to further reduce the speed of heat transfer between adjacent battery cells 1.

[0215] It is understandable that the positional relationship between the projection area of the preset surface 11a and the projection area of the second insulating layer 14 is not limited. Exemplarily, the projection area of the second insulating layer 14 is located within the projection area of the preset surface 11a.

[0216] In one embodiment, please refer to Figure 4 and Figure 5 , second insulating layers 14 are provided on opposite sides of the housing 11 along the first direction, and the two second insulating layers 14 are arranged at intervals.

[0217] In the embodiment of the present application, second insulating layers 14 are provided on opposite sides of the housing 11 along the first direction, and the two second insulating layers 14 are arranged at intervals, which is beneficial for the second insulating layer 14 to further limit the heat generated by the battery cell 1 in thermal runaway from directly transferring to the adjacent battery cell 1, and is beneficial for further reducing the heat transfer speed between adjacent battery cells 1.

[0218] Exemplarily, the second insulating layer 14 straddles opposite sides of the housing 11 along the first direction, one side of the housing 11 along the second direction away from the conductive terminal 12, and opposite sides of the housing 11 along the third direction, so that the second insulating layer 14 covers the remaining surfaces of the housing 11 except the surface where the conductive terminal 12 is located.

[0219] In one embodiment, please refer to Figures 1 to 5 , the first insulating layer 13 is a waterproof insulating layer, and the waterproof insulating layer can prevent moisture from entering the housing 11, and the waterproof insulating layer is attached to the second insulating layer 14.

[0220] It should be noted that, please refer to Figure 6 , there is an adhesive layer 15 between the waterproof insulating layer and the second insulating layer 14, and the adhesive layer 15 is used to closely attach the waterproof insulating layer to the second insulating layer 14, and the thickness of the adhesive layer 15 can be ignored.

[0221] In the embodiment of the present application, the waterproof insulating layer can prevent moisture from entering the housing 11, which is beneficial for reducing the possibility of short - circuit of the battery cell 1 caused by moisture entering the housing 11, and then is beneficial for improving the safety of the battery cell 1.

[0222] It is understandable that the positional relationship between the waterproof insulating layer and the second insulating layer 14 is not limited. Exemplarily, along the first direction, the waterproof insulating layer is located on the side of the second insulating layer 14 close to the housing 11, the waterproof insulating layer covers the remaining surfaces of the housing 11 except the surface where the conductive terminal 12 is located, and the second insulating layer 14 is arranged outside the waterproof insulating layer.

[0223] In one embodiment, please refer to Figure 6 , the second insulating layer 14 is located between the housing 11 and the first insulating layer 13.

[0224] Exemplarily, please refer to Figure 6 along the first direction, the second insulating layer 14 is located on the side of the waterproof insulating layer close to the corresponding housing 11. The waterproof insulating layer is disposed outside the second insulating layer 14, and the waterproof insulating layer covers the remaining surfaces of the housing 11 except for the surface where the conductive terminal 12 is located.

[0225] In the embodiment of the present application, the second insulating layer 14 is located between the housing 11 and the first insulating layer 13, which is beneficial for the second insulating layer 14 to limit the heat generated by the battery cell 1 in thermal runaway from directly transferring to the first insulating layer 13, and is beneficial for reducing the possibility of the first insulating layer 13 melting and perforating. The possibility of the first insulating layer 13 not perforating is increased, which is beneficial for suppressing the second insulating layer 14 from absorbing moisture, and then is beneficial for reducing the possibility of moisture invading into the housing 11 and causing a short circuit of the battery cell 1, so as to improve the safety of the battery cell 1.

[0226] In one embodiment, the second insulating layer 14 includes a plurality of sub-layers stacked in sequence along the thickness direction of the second insulating layer 14, and the thicknesses of the plurality of sub-layers are all less than or equal to 400 μm.

[0227] In the embodiment of the present application, the thicknesses of the plurality of sub-layers are all less than or equal to 400 μm, so that under the condition of having a certain strength, the texture of the sub-layers is relatively soft, which is beneficial for improving the convenience of disposing the second insulating layer 14 on the housing 11.

[0228] In one embodiment, the thicknesses of the plurality of sub-layers are all less than or equal to 200 μm.

[0229] In the embodiment of the present application, the thicknesses of the plurality of sub-layers are all less than or equal to 200 μm, so that under the condition of having a certain strength, the texture of the sub-layers is softer, which is beneficial for improving the convenience of disposing the second insulating layer 14 on the housing 11.

[0230] In one embodiment, please refer to Figures 1 to 5 the shape of the housing 11 is square.

[0231] In the embodiment of the present application, the square battery cell 1 is beneficial for the adjacent battery cells 1 to be arranged more closely, which is beneficial for improving the energy density of the battery device.

[0232] It can be understood that the shape of the battery cell 1 is not limited. Exemplarily, the shape of the battery cell 1 can be cylindrical.

[0233] In one embodiment, at least a part of the second insulating layer 14 corresponding to the battery cell 1 adjacent to the box body is located between the box body and the corresponding housing 11.

[0234] It should be explained that the battery cell 1 adjacent to the box body refers to that there is no other battery cell 1 between the battery cell 1 and the box body.

[0235] Exemplarily, the first insulating layer 13 and / or the second insulating layer 14 of the battery cell 1 adjacent to the box body are in contact with the box body.

[0236] In the embodiment of the present application, the second insulating layer 14 corresponding to the battery cell 1 adjacent to the box body is at least partially located between the box body and the corresponding outer shell 11, so as to reduce the possibility of insulation failure of the box body caused by the conduction between the battery cell 1 and the box body, and then is beneficial to reducing the possibility of constructing a high-voltage sparking circuit by the box body, which is beneficial to improving the safety of the battery device.

[0237] In one embodiment, among two adjacent battery cells 1, the second insulating layer 14 of at least one of the battery cells 1 is located between the outer shells 11 of the corresponding two adjacent battery cells 1.

[0238] In the embodiment of the present application, the second insulating layer 14 of at least one of the battery cells 1 is located between the outer shells 11 of the corresponding two adjacent battery cells 1, so that there is at least one second insulating layer 14 between the outer shells 11 of the two adjacent battery cells 1, which is beneficial to reducing the possibility of heat diffusion of the battery cell 1.

[0239] In one embodiment, the battery device further includes a mounting rack connected in the box body, the battery cell 1 is mounted on the mounting rack, and the second insulating layer 14 corresponding to the battery cell 1 adjacent to the mounting rack is at least partially located between the mounting rack and the corresponding outer shell 11.

[0240] In the embodiment of the present application, the second insulating layer 14 corresponding to the battery cell 1 adjacent to the mounting rack is at least partially located between the mounting rack and the corresponding outer shell 11, so as to reduce the possibility of insulation failure of the mounting rack caused by the conduction between the battery cell 1 and the mounting rack, and then is beneficial to reducing the possibility of constructing a high-voltage sparking circuit by the mounting rack, which is beneficial to improving the safety of the battery.

[0241] For the battery cell 1 in the embodiment of the present application, please refer to Figures 1 to 6, a second insulating layer 14 with a heat resistance temperature higher than that of the first insulating layer 13 is provided between the outer casings 11 of two adjacent battery cells 1. The second insulating layer 14 can cover the remaining surfaces of the outer casing 11 except the surface where the conductive terminal 12 is located; the second insulating layer 14 can be annular and surround the outside of the outer casing 11; the second insulating layer 14 can also be U-shaped and cover the outside of the outer casing 11; the second insulating layer 14 can also be located between two adjacent outer casings 11 and is only provided on the preset surface 11a of the outer casing 11 without straddling the remaining surfaces of the outer casing 11 except the preset surface 11a, which is beneficial to reducing the space loss of the remaining surfaces of the outer casing 11 except the preset surface 11a, and then beneficial to improving the utilization rate of the internal space of the battery device, and also beneficial to improving the heat dissipation efficiency of the battery cell 1. The first insulating layer 13 covers the remaining surfaces of the outer casing 11 except the surface where the conductive terminal 12 is located. By providing the second insulating layer 14 with a heat resistance temperature higher than that of the first insulating layer 13 between two adjacent outer casings 11, it is beneficial to reduce the heat transfer speed between adjacent battery cells 1, and also beneficial to reducing the possibility of short circuit caused by the lap between adjacent outer casings 11 and resulting in high-voltage spark breakdown, and then beneficial to improving the safety of the battery cell 1. The first insulating layer 13 and / or the second insulating layer 14 are in contact with the box body, and the first insulating layer 13 and / or the second insulating layer 14 are in contact with the mounting rack, which is beneficial to reducing the possibility of constructing a high-voltage spark circuit through the box body or the mounting rack and is beneficial to improving the safety of the battery device.

[0242] The energy density of the battery cell 1 can range from 320 Wh / L to 550 Wh / L, the heat resistance temperature of the second insulating layer 14 ranges from 180 °C to 450 °C. Further, the heat resistance temperature of the second insulating layer 14 can range from 250 °C to 400 °C. The ratio of the energy density of the battery cell 1 to the heat resistance temperature of the second insulating layer 14 ranges from 0.84 Wh / L / °C to 1.96 Wh / L / °C. Further, the ratio of the energy density of the battery cell 1 to the heat resistance temperature of the second insulating layer 14 ranges from 1.03 Wh / L / °C to 1.58 Wh / L / °C. The thickness of the second insulating layer 14 ranges from 50 μm to 700 μm, and the ratio of the energy density of the battery cell 1 to the thickness of the second insulating layer 14 ranges from 0.8 Wh / L / μm to 6.4 Wh / L / μm. Further, the ratio of the energy density of the battery cell 1 to the thickness of the second insulating layer 14 ranges from 0.8 Wh / L / μm to 3.7 Wh / L / μm. By limiting the ratio of the energy density of the battery cell 1 to the heat resistance temperature and thickness of the second insulating layer 14 within a relatively reasonable range, it is not only possible to reduce the possibility of perforation and melting loss of the second insulating layer 14, but also possible to improve the cost performance of the material used for the second insulating layer 14.

[0243] The first insulating layer 13 is designed as a waterproof insulating layer, which is beneficial to reducing the possibility of moisture intrusion into the housing 11 and causing a short circuit of the battery cell 1, and improving the safety of the battery cell 1. Along the first direction, the second insulating layer 14 is located on the side of the waterproof insulating layer close to the housing 11, which can reduce the possibility of the waterproof insulating layer being damaged by melting, is beneficial to inhibiting the second insulating layer 14 from absorbing moisture, and then is beneficial to reducing the possibility of moisture intrusion into the housing 11 and causing a short circuit of the battery cell 1, and improving the safety of the battery cell 1.

[0244] The second insulating layer 14 includes a plurality of sub-layers, and the thicknesses of the plurality of sub-layers are all less than or equal to 400 μm. Further, it can be less than or equal to 200 μm, which is beneficial to improving the convenience of arranging the second insulating layer 14.

[0245] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that, include: shell; an electrode assembly, located in the housing; A conductive terminal is mounted on the housing, and the conductive terminal is electrically connected to the electrode assembly; A first insulating layer, covering the outer shell to insulate the outer surface of the outer shell, the outer shell is located in the first insulating layer; The second insulating layer is arranged on the first insulating layer, and the second insulating layer is located on the side of the shell away from the electrode assembly. The heat resistance of the second insulating layer is greater than that of the first insulating layer.

2. The battery cell according to claim 1, wherein, The energy density of the battery cell is greater than or equal to 320Wh / L, the energy density of the battery cell is less than 390Wh / L, and the heat resistance temperature range of the second insulating layer is 180℃≤T≤450℃; or, the energy density of the battery cell is greater than or equal to 390Wh / L, the energy density of the battery cell is less than 490Wh / L, and the heat resistance temperature range of the second insulating layer is 220℃≤T≤450℃; or, the energy density of the battery cell is greater than or equal to 490Wh / L, the energy density of the battery cell is less than 550Wh / L, and the heat resistance temperature range of the second insulating layer is 250℃≤T≤450℃.

3. The battery cell according to claim 1, characterized in that, The material of the first insulating layer is polyethylene terephthalate or polycarbonate, and the material of the second insulating layer is polypropylene, polyethylene, polyamide, polyethylene terephthalate, polyphthalamide, polyphenylene sulfide or polyimide.

4. The battery cell according to claim 1, characterized in that, The energy density of the battery cell is greater than or equal to 320Wh / L, the energy density of the battery cell is less than 390Wh / L, and the thickness of the second insulating layer is 50μm to 700μm; or, the energy density of the battery cell is greater than or equal to 390Wh / L, the energy density of the battery cell is less than 490Wh / L, and the thickness of the second insulating layer is 70μm to 700μm; or, the energy density of the battery cell is greater than or equal to 490Wh / L, the energy density of the battery cell is less than 550Wh / L, and the thickness of the second insulating layer is 100μm to 700μm.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The outer surface of the shell with the largest area is a preset surface, the direction perpendicular to the preset surface is a first direction, and the second insulating layer is at least partially located on at least one side of the shell along the first direction.

6. The battery cell according to claim 5, characterized in that, The second insulating layer is annular in shape and is arranged to form a receiving cavity and an opening communicating with the receiving cavity. The openings are arranged on opposite sides of the receiving cavity. The outer shell is located in the receiving cavity corresponding to the second insulating layer.

7. The battery cell according to claim 5, characterized in that, The second insulating layer includes a main film and a first sub-membrane. The main films are arranged on opposite sides of the outer shell along the first direction. The first sub-membrane is connected between the main films on the corresponding two sides. The arrangement direction of the conductive terminals and the electrode assemblies is a second direction. The second direction is arranged crosswise with the first direction. The first sub-membrane is located on the side of the outer shell away from the conductive terminals along the second direction.

8. The battery cell according to claim 7, characterized in that, The second insulating layer also includes a second sub-membrane, and the second sub-membrane is arranged on opposite sides of the outer shell along the third direction. The third direction is arranged to cross the first direction and the second direction respectively. The first direction, the second direction and the third direction are not coplanar. The second sub-membrane is respectively connected to the first sub-membrane and the main membranes on both sides. The second sub-membrane on each side forms an avoidance cavity, and the space enclosed by the main membrane, the first sub-membrane and the second sub-membrane is connected to the avoidance cavity.

9. The battery cell according to claim 7, wherein Projected along the second direction, a projection area of ​​a surface of the housing that is away from the conductive terminal along the second direction is located within the projection area of ​​the first sub-film.

10. The battery cell according to claim 7, characterized in that, The thickness of the main film is greater than the thickness of the first sub-film.

11. The battery cell according to claim 10, wherein The first sub-film is located between the housing and the heat management component.

12. The battery cell according to claim 5, wherein Projected along the first direction, the projection area of ​​the preset surface is located within the projection area of ​​the second insulating layer.

13. The battery cell according to claim 5, characterized in that, The second insulating layers are disposed on two opposite sides of the housing along the first direction, and the second insulating layers on the two sides are arranged at intervals.

14. The battery cell according to any one of claims 1 to 4, characterized in that, The first insulating layer is a waterproof insulating layer, which can prevent moisture from invading the housing, and the waterproof insulating layer is bonded to the second insulating layer.

15. The battery cell according to claim 14, characterized in that, The second insulating layer is located between the housing and the first insulating layer.

16. The battery cell according to any one of claims 1 to 4, characterized in that, The second insulating layer includes a plurality of sub-layers stacked in sequence along a thickness direction of the second insulating layer, and the thickness of each of the plurality of sub-layers is less than or equal to 400 μm.

17. The battery cell according to claim 16, characterized in that, The thickness of each of the sub-layers is less than or equal to 200 μm.

18. The battery cell according to any one of claims 1 to 4, characterized in that, The shell is in a square shape.

19. A battery device, characterized in that, include: The battery cell according to any one of claims 1 to 18; A box body, wherein the battery cell is located in the box body.

20. The battery device according to claim 19, characterized in that, The second insulating layer corresponding to the battery cell adjacent to the case is at least partially located between the case and the corresponding outer shell.

21. The battery device according to claim 19, wherein, Among two adjacent battery cells, the second insulating layer of at least one of the battery cells is located between the outer shells of the corresponding two adjacent battery cells.

22. The battery device according to claim 19, wherein, The battery device further comprises a mounting frame connected to the box body, the battery cells are mounted on the mounting frame, and the second insulating layer corresponding to the battery cells adjacent to the mounting frame is at least partially located between the mounting frame and the corresponding housing.

23. An electrical device, characterized in that, include: The battery device according to any one of claims 19 to 22; The battery device is arranged on the electricity-consuming subject, and the battery device provides power for the electricity-consuming subject.

24. A energy storage device, characterized in that, include: The battery device according to any one of claims 19 to 22, wherein the battery device is capable of storing electricity; An installation box, wherein the battery device is arranged in the installation box.

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