Single battery, battery pack and vehicle

Abstract

The utility model relates to the technical field of batteries, and discloses a single battery, a battery pack and a vehicle, the single battery comprises a shell, a naked battery cell, an insulating layer and a thermal resistance layer, and the naked battery cell is accommodated in the shell; the insulating layer coats the outer side of the naked battery cell so as to isolate the naked battery cell from the shell; and the thermal resistance layer is arranged between the shell and the insulating layer and is used for reducing heat conduction between the naked battery cell and the shell. During application, the thermal resistance layer can shield the space between the shell and the naked battery cell to achieve a certain thermal insulation effect on the shell, and during thermal runaway, the thermal resistance layer can isolate the naked battery cell from at least part of the inner wall of the shell to reduce heat conduction between the naked battery cell and the shell, so that the temperature rise rate of the shell is effectively slowed down, the cracking risk of the shell is reduced, and the service life of the shell is prolonged. Therefore, the interlocking thermal runaway risk is effectively reduced, and the safety of the battery pack and the vehicle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a single battery, a battery pack and a vehicle. BACKGROUND

[0002] In the related art, in order to improve the energy density of the battery, the single battery generally adopts an outer shell with a relatively thin wall thickness. Therefore, when the single battery is in thermal runaway, the outer shell is easily broken under pressure, which affects the adjacent single battery or other structures, leading to a chain thermal runaway, and seriously affecting the safety of the battery. CONTENT OF THE UTILITY MODEL

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a single battery which effectively reduces the risk of chain thermal runaway. The present application also proposes a battery pack and a vehicle having the single battery.

[0004] In a first aspect, the single battery of the embodiments of the present application comprises a shell, a bare cell, an insulation layer and a thermal resistance layer, the bare cell is accommodated in the shell; the insulation layer is wrapped on the outer side of the bare cell to isolate the bare cell from the shell; the thermal resistance layer is arranged between the shell and the insulation layer, and is used to reduce the heat conduction between the bare cell and the shell.

[0005] The single battery according to the embodiments of the present application has at least the following beneficial effects: the thermal resistance layer is arranged between the shell and the insulation layer, so that the thermal resistance layer can shield between the bare cells of the shell, and play a certain heat insulation role for the shell. In the case of thermal runaway, the thermal resistance layer can isolate the bare cell and at least part of the inner wall of the shell, reduce the heat conduction between the bare cell and the shell, effectively slow down the temperature rising rate of the shell, reduce the risk of shell rupture, and further effectively reduce the risk of chain thermal runaway, and improve the safety of the battery.

[0006] According to some embodiments of the present application, the shell comprises a pair of first walls arranged oppositely, and a pair of second walls arranged oppositely, the second walls are connected between the pair of first walls; wherein the inner side of at least one of the first walls is provided with the thermal resistance layer, and / or the inner side of at least one of the second walls is provided with the thermal resistance layer.

[0007] According to some embodiments of the present application, the thermal resistance layer arranged on the inner side of the first wall is connected to the thermal resistance layer arranged on the inner side of the second wall.

[0008] According to some embodiments of the present application, the inner side of the first wall and the second wall is provided with the thermal resistance layer, and the thermal conductivity coefficient of the thermal resistance layer on the inner side of at least one of the second walls is higher than that of the remaining thermal resistance layers.

[0009] According to some embodiments of the present application, the first wall has a larger area than the second wall.

[0010] According to some embodiments of the present application, the thermal resistance layer has a melting point not lower than 500°C; and / or, the thermal resistance layer has a thermal conductivity not higher than 1.

[0011] According to some embodiments of the present application, the thermal resistance layer is attached to the inner surface of the shell; or, the thermal resistance layer is attached to the outer wall of the insulation layer; or, the thermal resistance layer is sandwiched between the insulation layer and the shell.

[0012] According to some embodiments of the present application, the thermal resistance layer is attached to the inner surface of the shell; or, the thermal resistance layer is attached to the outer wall of the insulation layer; or, the thermal resistance layer is sandwiched between the insulation layer and the shell.

[0013] In a second aspect, the battery pack according to an embodiment of the present application includes a box body and the single battery according to the first aspect, and the box body has an inner cavity, and the plurality of single batteries are arranged in the inner cavity of the box body. When a part of the single batteries is in thermal runaway, the thermal resistance layer can effectively slow down the temperature rising rate of the shell, thereby reducing the risk of shell rupture, avoiding the spread of thermal runaway to adjacent single batteries in the box body, effectively reducing the risk of chain thermal runaway, and improving the safety of the battery.

[0014] In a third aspect, the vehicle according to an embodiment of the present application includes the single battery according to the first aspect. When a part of the single batteries is in thermal runaway, the thermal resistance layer can effectively reduce the risk of shell rupture, thereby reducing the risk of thermal runaway spreading to adjacent single batteries on the vehicle or other structures on the vehicle, and effectively improving the safety of the vehicle.

[0015] In a fourth aspect, the vehicle according to an embodiment of the present application includes the battery pack according to the second aspect. When a part of the single batteries in the box body is in thermal runaway, the thermal resistance layer can effectively reduce the risk of shell rupture, thereby reducing the risk of chain thermal runaway reaction in the battery pack, and improving the safety of the vehicle.

[0016] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 An exploded schematic view of a single battery according to an embodiment of the present application;

[0018] Figure 2 A sectional view of a single battery according to another embodiment of the present application;

[0019] Figure 3 A sectional view of a single battery according to another embodiment of the present application; Figure 2 A partial enlarged view of A in FIG. 4;

[0020] Figure 4 This is an exploded schematic diagram of a single cell battery according to another embodiment of this application;

[0021] Figure 5 This is an exploded schematic diagram of a single cell battery according to another embodiment of this application.

[0022] Figure label:

[0023] Bare battery cell 100; Insulation layer 200; Thermal resistance layer 300; Housing 400; First wall 410; Second wall 420; Opening 430; Top cover assembly 500; Spacing 600. Detailed Implementation

[0024] The following will clearly and completely describe the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, features and effects of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.

[0025] In the description of the embodiments of this application, if directional descriptions are involved, such as "up", "down", "front", "back", "left", "right" etc., indicating the directional or positional relationship based on the directional or positional relationship shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] In the description of the embodiments of this application, if a feature is referred to as "setting," "fixing," "connecting," or "installing" on another feature, it can be directly set, fixed, or connected to the other feature, or it can be indirectly set, fixed, connected, or installed on the other feature. In the description of the embodiments of this application, if "several" is involved, it means one or more; if "multiple" is involved, it means two or more; if "greater than," "less than," or "exceeds," it should be understood as excluding the stated number; if "above," "below," or "within," it should be understood as including the stated number. If "first" or "second" is involved, it should be understood as used to distinguish technical features, and not as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0027] A single battery cell generally includes a bare cell and a container with an internal environment for housing the bare cell. The bare cell includes a positive electrode, a negative electrode, and a separator for separating the positive and negative electrodes. The internal environment of the container contains an electrolyte, and the bare cell operates while immersed in the electrolyte environment.

[0028] A battery device typically comprises multiple individual cells, which are electrically connected in series, parallel, or a combination thereof to form a whole, providing power to electrical devices. The individual cells involved in the embodiments of this application can be cylindrical, prismatic, or blade batteries.

[0029] The battery devices involved in this application's embodiments can be battery modules, battery packs, or energy storage modules assembled on electrical equipment. The battery modules involved in this application's embodiments may include side plates, end plates, and multiple individual batteries, with the side plates and end plates fixing and assembling the multiple individual batteries to form an independent battery module. The battery packs involved in this application's embodiments may include a housing and multiple individual batteries, with the individual batteries housed within the housing. Alternatively, the battery pack may include a housing and multiple battery modules, with the multiple battery modules housed within the housing. The energy storage modules involved in this application's embodiments may include multiple individual batteries, with the multiple individual batteries housed within a accommodating space provided on the electrical equipment.

[0030] The electrical equipment involved in the embodiments of this application can be vehicles, ships, aircraft, etc. The vehicles involved in the embodiments of this application are vehicles equipped with battery devices, such as new energy vehicles equipped with battery devices, which can be hybrid vehicles or pure electric vehicles. Specifically, the vehicles can be private cars, such as sedans, SUVs, MPVs, or pickup trucks. The vehicles can also be commercial vehicles, such as vans, buses, small trucks, or large semi-trailers.

[0031] During charging and discharging, individual battery cells are prone to thermal runaway. For example, failure of the positive and negative electrodes or separator can lead to internal short circuits, resulting in thermal runaway. When thermal runaway occurs in a single battery cell, a large amount of heat and gas is generated, causing a rapid increase in the temperature of the bare cell and the internal pressure of the container. The container is prone to rupture due to heat and pressure. After the container ruptures, the heat spreads uncontrollably to the surrounding environment, affecting adjacent battery cells or other structures, thus triggering a chain reaction of thermal runaway and reducing the reliability of the individual battery cell.

[0032] This application proposes a single-cell battery that effectively reduces the risk of cascading thermal runaway. When applied, it can effectively reduce the risk of casing rupture, thereby reducing the risk of cascading thermal runaway.

[0033] refer to Figures 1 to 3The single-cell battery of this application embodiment includes a casing 400, a bare cell 100, an insulating layer 200, and a thermal resistance layer 300. The casing 400 provides an internal environment for housing the bare cell 100, which is housed within the casing 400. The insulating layer 200 covers the outside of the bare cell 100, effectively isolating the bare cell 100 from the casing 400 and preventing short circuits between them. The thermal resistance layer 300 is disposed between the casing 400 and the insulating layer 200, thus providing a certain degree of heat insulation between the casing 400 and the bare cell 100. In the event of thermal runaway, the thermal resistance layer 300 can isolate the bare cell 100 and at least part of the inner wall of the casing 400, reducing the heat conduction between the bare cell 100 and the casing 400, thereby effectively slowing down the heating rate of the casing 400, reducing the risk of casing 400 rupture, and thus effectively reducing the risk of chain thermal runaway and improving battery safety.

[0034] refer to Figures 1 to 3 The thermal resistance layer 300 is disposed on the inner side of at least a portion of the housing 400, and can play a certain role in heat insulation within the housing 400. Furthermore, the thermal resistance layer 300 is located on the outer side of the insulating layer 200, which can avoid affecting the wrapping of the bare battery cell 100 by the insulating layer 200 and ensure the insulation effect.

[0035] refer to Figures 1 to 3 In some embodiments, the housing 400 includes a pair of first walls 410 disposed opposite to each other, and a pair of second walls 420 disposed opposite to each other. The second walls 420 are connected between the pair of first walls 410, and the first walls 410 and the second walls 420 together form a rectangular housing 400 structure with an inner cavity. Therefore, multiple individual cells can be conveniently arranged along the setting direction of the first walls 410, and the first walls 410 of adjacent individual cells are arranged adjacent to each other.

[0036] In this embodiment, at least one of the inner sides of the first wall 410 is provided with a thermal resistance layer 300, for example, referring to Figure 4 Both first walls 410 have a thermal resistance layer 300 on their inner sides, or one of the first walls 410 has a thermal resistance layer 300 on its inner side. This effectively reduces the risk of the first wall 410 cracking and prevents thermal runaway from spreading to adjacent single cells. Alternatively, at least one second wall 420 has a thermal resistance layer 300 on its inner side, for example, referring to... Figure 5 Both second walls 420 have a thermal resistance layer 300 on their inner sides, or one of the second walls 420 has a thermal resistance layer 300 on its inner side. This can effectively reduce the risk of the second wall 420 cracking and prevent heat from spreading from the outside of the second wall 420 to adjacent single cells or other structures.

[0037] refer to Figure 1In a design where thermal resistance layers 300 are provided on the inner sides of adjacent walls, the thermal resistance layers 300 of adjacent walls can be connected. For example, the thermal resistance layer 300 provided on the inner side of the first wall 410 is connected to the thermal resistance layer 300 provided on the inner side of the second wall 420. Thus, the thermal resistance layer 300 can shield the junction formed by the intersection of the first wall 410 and the second wall 420, ensuring thermal resistance at the junction position. Alternatively, the thermal resistance layers 300 on the inner sides of different walls can be independent of each other. For example, the thermal resistance layers 300 on the inner sides of the first wall 410 and the second wall 420 can be independent of each other, ensuring the thermal resistance of the walls while reducing the difficulty of processing or assembly.

[0038] refer to Figures 1 to 3 In some embodiments, the area of ​​the first wall 410 is larger than the area of ​​the second wall 420. That is, the first wall 410 is the larger surface of the battery casing 400, and the second wall 420 is the smaller surface of the casing 400 of a single battery cell. In application, multiple single batteries can be arranged by placing their larger surfaces adjacent to each other, which can effectively utilize space for compact arrangement. In some embodiments, the area of ​​the first wall 410 can also be the same as the area of ​​the second wall 420, or have a small difference, which can be reasonably configured according to the actual bare cell structure 100 and the arrangement needs of the single batteries.

[0039] In one example, when multiple individual cells are used in a battery module, battery pack, or electrical equipment, adjacent individual cells can be arranged along the setting direction of the first wall 410. A thermal resistance layer 300 is set between adjacent first walls 410 to effectively isolate heat. Therefore, heat may break through the second wall 420 and spread to the surrounding area. Thus, the thermal resistance layer 300 set on the inner side of the second wall 420 can effectively prevent thermal runaway chain reaction.

[0040] refer to Figure 1 In some embodiments, thermal resistance layers 300 can be provided on the inner sides of the two first walls 410 and the two second walls 420, thereby circumferentially separating the bare battery cell 100 from the housing 400 and achieving effective protection of the four walls.

[0041] In some embodiments, the thermal conductivity of the inner thermal resistance layer 300 of at least one of the first wall 410 and the second wall 420 is higher than that of the other thermal resistance layers 300. For example, at least one first wall 410 and at least one second wall 420 are provided with thermal resistance layers 300 on their inner sides, wherein the thermal conductivity of the thermal resistance layer 300 on the inner side of at least one second wall 420 is higher than that of the other thermal resistance layers 300. Alternatively, both second walls 420 are provided with thermal resistance layers 300 on their inner sides, and the thermal conductivity of the thermal resistance layers 300 on the inner sides of both second walls 420 is higher than that of the thermal resistance layer 300 on the inner side of the first wall 410. Alternatively, in other embodiments, at least one second wall 420 is not provided with a thermal resistance layer 300. Therefore, the second wall 420 with a thermal resistance layer 300 having a higher thermal conductivity or the second wall 420 without a thermal resistance layer 300 can effectively conduct internal heat outward through the housing 400. In application, a cooling device can be provided corresponding to the second wall 420, for example, the second wall 420 can be attached to a water cooling device, or the second wall 420 can be provided in an air cooling channel. Thus, under the normal working condition of the single cell, the inside of the casing 400 can be effectively cooled by heat conduction, reducing the risk of thermal runaway inside the single cell.

[0042] refer to Figures 1 to 3 In some embodiments of the single-cell battery, the housing 400 has an opening 430 at at least one end along a first direction, or the housing 400 has openings 430 at both ends along the first direction. In a rectangular structure, the first direction can be the length, width, or height of the housing 400; in a cylindrical structure, the first direction can be the axial direction of the housing 400. The single-cell battery also includes a top cover assembly 500, which covers the opening 430 and is connected to the end. The top cover assembly 500, together with the housing 400, forms a closed internal environment for accommodating the bare cell 100. The top cover assembly 500 includes a cover plate, terminals, and an explosion-proof valve commonly used on single-cell top cover assemblies 500. The cover plate is used to seal the opening 430 of the housing 400 and is connected to the end of the housing 400 located at the opening 430. The terminals are located on the cover plate and are used to connect to the tabs of the bare cell 100 to realize current transmission. The explosion-proof valve is located on the cover plate and is used to open under a preset pressure to realize venting and pressure relief, thereby dissipating the heat inside the housing 400 to the outside.

[0043] There is a gap of 600 between the end of the housing 400 located at the opening 430 and the thermal resistance layer 300 inside the housing 400, thereby reserving a connection space for the top cover assembly 500. For example, the cover plate is connected to the end of the housing 400 by welding. The reserved connection space can ensure a stable connection between the cover plate and the end of the housing 400, and ensure sealing performance.

[0044] The single-cell battery in this application embodiment can be a cylindrical battery, a prismatic battery, or a blade battery. It is understood that the length of a blade battery is generally much greater than its thickness, thus forming a blade-like shape. That is, the casing 400 of the blade battery generally has a relatively long length and a relatively thin thickness. The casing 400 has openings 430 at both ends along its rectangular length. A top cover assembly 500 covers the openings 430 at both ends. The top cover assembly 500 and the casing 400 together form an internal environment for accommodating the bare cell 100. The top cover assembly 500 includes an explosion-proof valve for releasing pressure in the event of thermal runaway. Because the casing 400 of the blade battery has a relatively long length and the top cover assemblies 500 at both ends are far apart, hot air rushes out from the explosion-proof valves at both ends to release pressure during thermal runaway. The path of the hot air discharge is relatively long, thus it remains inside the casing 400 for a relatively long time, resulting in the casing 400 being subjected to heat and pressure for a longer period, making the casing 400 easily damaged. Furthermore, the casing 400 of the blade battery generally has a relatively thin wall thickness. During the process of opening the explosion-proof valve to release air and pressure, the local temperature of the casing 400 may become too high, which can easily soften the material and reduce its mechanical properties, thus making it prone to cracking and failure.

[0045] Compared to ordinary blade batteries, in the blade battery of this application embodiment, the thermal resistance layer 300 can provide a certain degree of heat insulation for the casing 400, which helps to reduce heat conduction to the casing 400, prolongs the time for the casing 400 to reach its maximum temperature, and helps to extend the venting time and heat dissipation time of the explosion-proof valve, so as to achieve directional heat discharge. The increased venting time can effectively reduce internal heat, thereby reducing the maximum temperature of the casing 400 during thermal runaway and reducing the risk of casing rupture and failure.

[0046] In some embodiments, the thermal resistance layer 300 can be made into a thin coating, sticker or other structure, which occupies less space inside the housing 400 and has less impact on energy density.

[0047] In some embodiments, the thermal resistance layer 300 can be attached to the inner surface of the housing 400. For example, the thermal resistance layer 300 can be adhered to the inner surface of the housing 400, thereby directly blocking the housing 400 from internal materials (such as the bare battery cell 100, the insulating layer 200, the electrolyte, or gases generated during thermal runaway). This forms a stable thermal resistance on the inner surface of the housing 400, preventing a gap between the thermal resistance layer 300 and the housing 400 from affecting the heat insulation effect. Alternatively, the thermal resistance layer 300 can be attached to the outer wall of the insulating layer 200. For example, the thermal resistance layer 300 can be adhered to or coated on the outer surface of the insulating layer 200. In the event of thermal runaway, if the insulating layer 200 melts, the thermal resistance layer 300 can block the outside of the bare battery cell 100, reducing the transfer of heat from the bare battery cell 100 to the housing 400. Alternatively, the thermal resistance layer 300 can be a structure independently disposed within the housing 400. The thermal resistance layer 300 is sandwiched between the insulating layer 200 and the housing 400, which facilitates assembly and effectively prevents the formation of thermal resistance between the bare cell 100 and the housing 400.

[0048] The thermal resistance layer 300 attached to the inner surface of the housing 400 can be a coating, a patch or film, etc., applied to the inner surface of the housing 400; the thermal resistance layer 300 attached to the outer wall of the insulating layer 200 can be a coating, a patch or film, etc., applied to the outer wall of the insulating layer 200; the thermal resistance layer 300 sandwiched between the insulating layer 200 and the housing 400 can be a sheet-like or film-like structure independently disposed within the housing 400.

[0049] As an example, the thermal resistance layer 300 may include a mica layer, which can be adhered to or coated on the inner surface of the housing 400. The mica layer is made of mica, which has excellent high-temperature insulation properties and a high melting point. The mica layer forms a stable thermal resistance between the bare cell 100 and the housing 400. The thermal conductivity of the mica layer is no higher than 1, effectively reducing heat conduction between the bare cell 100 and the housing 400. Furthermore, mica material has good chemical stability, exhibiting a certain degree of corrosion resistance to acidic and alkaline environments, and is not easily affected by internal battery chemicals (such as electrolytes). The mica layer can be common mica products such as mica paper, mica tape, or mica coating. The following is a brief introduction to the forms of several different mica products; specific manufacturing processes and materials are not detailed here.

[0050] Commonly used mica paper is generally made from mica material through thermochemical or hydraulic stripping and pulping into sheet form. It can be cut into single sheets or strips of the required size. In addition to its good high-temperature resistance and insulation properties, mica paper also has good flexibility, allowing it to adhere well to the inner surface of the housing 400 or the outer surface of the insulation layer 200. Mica coating is generally made by dispersing mica powder in deionized water and adding other materials (such as silicone) to create a slurry containing mica powder. The slurry is then coated onto the desired surface (such as the inner surface of the housing 400 or the outer surface of the insulation layer 200) to obtain the mica coating. Mica coating can be easily applied to large surfaces.

[0051] In some embodiments, the thermal resistance layer 300 can be an inorganic oxide coating or patch with low thermal conductivity, exhibiting good affinity for the electrolyte. Alternatively, the thermal resistance layer 300 can be a high-temperature resistant metal coating with good chemical stability. The thermal resistance layer 300 can also be an alumina or zirconia-based ceramic coating, which can be sprayed during the production of the housing 400 to form a housing 400 with the thermal resistance layer 300 on its inner surface, and then assembled with the bare battery cell 100 encased in the insulating layer 200. The thermal resistance layer 300 can also be an alumina or zirconia-based ceramic fiber paper, adhered to the inner surface of the housing 400 or the outer surface of the insulating layer 200.

[0052] The thermal resistance layer 300 has a high melting point, which can maintain good structural stability during thermal runaway, thus providing good thermal insulation for the casing 400. Generally, when a single cell experiences thermal runaway, the peak internal temperature is typically between 600°C and 650°C. It is understood that during thermal runaway, the internal temperature of the casing 400 gradually rises, potentially reaching or falling below the peak temperature. In other words, during thermal runaway of a single cell, the internal temperature of the casing 400 may be below 600°C. In some embodiments of this application, the melting point of the thermal resistance layer 300 is not lower than 500°C. That is, the melting point of the thermal resistance layer 300 can be 500°C or higher. During the temperature rise, the internal gas pressure of the casing 400 increases, causing it to break through the explosion-proof valve of the top cover assembly 500 to release gas and pressure, while simultaneously dissipating a large amount of heat. Before the temperature reaches the melting point of the thermal resistance layer 300, the insulating layer 200 will generally be melted first, exposing the bare cell 100. The thermal resistance layer 300 blocks the bare cell 100 and the casing 400, which can prevent the bare cell 100 and the casing 400 from contacting and conducting heat, thereby preventing the local temperature of the casing 400 from rising rapidly. This reduces the heating rate of the casing 400 and prolongs the time before the casing 400 reaches rupture failure. This can effectively prolong the time for venting and depressurization, realize the directional discharge of heat inside the casing 400, and also reduce the maximum temperature of the casing 400 during thermal runaway, thereby reducing the risk of the casing 400 rupture failure.

[0053] In some embodiments, the melting point of the thermal resistance layer 300 may be 650°C or higher, which can effectively resist the peak temperature of thermal runaway and maintain stable thermal resistance. In some embodiments, the housing 400 may be made of aluminum, which is commonly used in single-cell batteries. The melting point of aluminum is typically 600°C to 660°C. The melting point of the thermal resistance layer 300 may be higher than that of the housing 400, which can effectively prevent the thermal resistance layer 300 from cracking and failing during thermal runaway exhaust, thus providing effective thermal resistance for the housing 400.

[0054] Understandably, the specific melting point of the thermal resistance layer 300 varies depending on the material selection, structural thickness, and other factors. For example, when the thermal resistance layer 300 uses mica products, which can withstand high temperatures of 800℃ to 1200℃, the melting point of the thermal resistance layer 300 can be between 800℃ and 1200℃, such as 800℃, 900℃, 1000℃, 1100℃, 1200℃, or any other value between 800℃ and 1200℃. When the thermal resistance layer 300 uses other high-performance high-temperature resistant materials (such as some inorganic oxides), its melting point can be higher than 1200℃.

[0055] The thermal resistance layer 300 also has low thermal conductivity; in some embodiments, the thermal conductivity of the thermal resistance layer 300 is no higher than 1. The low thermal conductivity of the thermal resistance layer 300 provides better thermal insulation, reducing heat transfer between the bare battery cell 100 and the housing 400, thereby reducing the heating rate of the housing 400. It is understood that the specific thermal conductivity of the thermal resistance layer 300 varies depending on the material selection, structural thickness, etc. For example, when the thermal resistance layer 300 uses mica products, its thermal conductivity can range from 0.04 W / (m·K) to 0.63 W / (m·K). For instance, among common mica products, some mica paper has a thermal conductivity of 0.04 W / (m·K), some mica tape has a thermal conductivity of 0.3 W / (m·K) to 0.5 W / (m·K), and some mica sheets have a thermal conductivity of 0.63 W / (m·K).

[0056] The thermal resistance layer 300 can simultaneously have a high melting point and low thermal conductivity. When a single cell experiences thermal runaway, it can effectively reduce the conduction of heat from the bare cell 100 to the casing 400, thereby reducing the risk of the casing 400 material softening, mechanical properties deteriorating, and cracking under pressure, and thus reducing the risk of a chain reaction of thermal runaway.

[0057] The battery pack of this application embodiment includes a housing and individual cells from any of the above embodiments. The housing has an inner cavity, and multiple individual cells are disposed within the inner cavity of the housing. When some individual cells experience thermal runaway, the thermal resistance layer 300 can effectively slow down the heating rate of the housing 400, thereby reducing the risk of housing 400 rupture and preventing thermal runaway from spreading to adjacent individual cells within the housing. This effectively reduces the risk of cascading thermal runaway and improves battery safety.

[0058] One embodiment of this application includes a single battery cell of any of the above embodiments. Multiple single batteries cells can be assembled on the vehicle body structure. When some single batteries cell experience thermal runaway, the thermal resistance layer 300 can effectively reduce the risk of the casing 400 rupture, thereby reducing the risk of thermal runaway spreading to adjacent single batteries cell or other structures on the vehicle, and effectively improving the safety of the vehicle.

[0059] Another embodiment of the vehicle of this application includes the battery pack of any of the above embodiments. The battery pack can be used as the power battery of the vehicle. When some individual cells in the battery pack experience thermal runaway, the thermal resistance layer 300 can effectively reduce the risk of the casing 400 breaking, thereby reducing the risk of chain thermal runaway reaction inside the battery pack and improving the safety of the vehicle.

[0060] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A single cell characterized by, The single battery comprises: a housing; a bare battery cell accommodated in the housing; an insulation layer covering the outer side of the bare battery cell to separate the bare battery cell from the housing; a thermal resistance layer arranged between the housing and the insulation layer, the thermal resistance layer being used to reduce the heat conduction between the bare battery cell and the housing.

2. The cell according to claim 1, wherein The housing comprises a pair of first walls arranged oppositely, and a pair of second walls arranged oppositely and connected between the pair of first walls; wherein, the inner side of at least one of the first walls is provided with the thermal resistance layer, and / or the inner side of at least one of the second walls is provided with the thermal resistance layer.

3. The cell according to claim 2, wherein The thermal resistance layer arranged on the inner side of the first wall is connected to the thermal resistance layer arranged on the inner side of the second wall.

4. The cell according to claim 2, wherein The inner side of the first wall and the inner side of the second wall are both provided with the thermal resistance layer, and the thermal conductivity coefficient of the thermal resistance layer on the inner side of at least one of the second walls is higher than that of the remaining thermal resistance layers.

5. The cell according to claim 2, wherein The area of the first wall is larger than that of the second wall.

6. The cell according to claim 1, wherein The melting point of the thermal resistance layer is not lower than 500℃; and / or the thermal conductivity coefficient of the thermal resistance layer is not higher than 1.

7. The cell according to claim 1, wherein The thermal resistance layer is attached to the inner surface of the housing; alternatively, the thermal resistance layer is attached to the outer wall of the insulation layer; alternatively, the thermal resistance layer is sandwiched between the insulation layer and the housing.

8. The cell according to claim 7, wherein The thermal resistance layer is pasted on the inner surface of the housing or the outer surface of the insulation layer; alternatively, the thermal resistance layer is coated on the inner surface of the housing or the outer surface of the insulation layer.

9. A battery pack, characterized by The battery pack comprises: a box body having an inner cavity; a plurality of single batteries as claimed in any one of claims 1 to 8 arranged in the inner cavity of the box body.

10. Vehicle, characterized in that The vehicle comprises the single battery as claimed in any one of claims 1 to 8, or the vehicle comprises the battery pack as claimed in claim 9.

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