Battery device and electric device

Abstract

The utility model discloses a battery device and an electric device. The battery device comprises a plurality of single batteries, a composite heat insulation pad is arranged between every two adjacent single batteries, each composite heat insulation pad comprises at least one first heat insulation layer and at least one second heat insulation layer, and the first heat insulation layers and the second heat insulation layers are alternately stacked. The first heat insulation layer is a ceramic fiber heat insulation layer or an aerogel heat insulation layer, and the emissivity of the second heat insulation layer is smaller than or equal to 0.3. The first heat insulation layer can play a better role in insulating heat conduction and heat convection; in the heat transfer process, besides heat conduction and heat convection, the form further comprises heat radiation, the higher the temperature is, the larger the radiant heat proportion is, the emissivity of the second heat insulation layer is low, most of the radiant heat can be isolated, the second heat insulation layer and the first heat insulation layer are structurally compounded, the total heat of heat transfer between the battery monomers can be reduced, and the heat transfer efficiency is improved. Therefore, the risk of thermal runaway of the battery device is reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery devices and electrical devices. Background Technology

[0002] Battery cells may experience thermal runaway due to overcharging or over-discharging, short circuits, impacts or vibrations, high temperatures, oxidation, mechanical abuse, or problems with internal components. The resulting exothermic chain reaction can lead to overheating, fire, or even explosion of the battery device, causing a rapid change in its self-temperature rise rate. To prevent heat dissipation, a common method is to use thermal insulation pads (made of ceramic fiber or aerogel) between adjacent battery cells to isolate heat conduction and convection, thus reducing the surface temperature of battery cells adjacent to those with higher temperatures. However, the thermal insulation performance of the thermal insulation pads currently used between battery cells still needs improvement to reduce the risk of thermal runaway in battery devices. Utility Model Content

[0003] In view of the technical problems existing in the background art, the present invention provides a battery device, which aims to improve the heat insulation performance of the heat insulation pad and reduce the risk of thermal runaway of the battery device.

[0004] In one aspect, this utility model provides a battery device. In some embodiments of this utility model, the battery device includes a plurality of battery cells, and a composite heat insulation pad is disposed between adjacent battery cells. The composite heat insulation pad includes at least one first heat insulation layer and at least one second heat insulation layer, the first heat insulation layer and the second heat insulation layer being alternately stacked. The first heat insulation layer is a ceramic fiber heat insulation layer or an aerogel heat insulation layer, and the emissivity of the second heat insulation layer is ≤0.3.

[0005] The first insulation layer can effectively isolate heat conduction and heat convection. In the process of heat transfer, in addition to heat conduction and heat convection, it also includes heat radiation. The higher the temperature, the greater the proportion of radiant heat. The second insulation layer has a low emissivity and can isolate most of the radiant heat. By using the second insulation layer and the first insulation layer in a structural composite, the total heat transfer between battery cells can be reduced, thereby reducing the cold surface temperature of battery cells adjacent to those with higher temperatures, and thus reducing the risk of thermal runaway of the battery device to at least a certain extent.

[0006] In some embodiments of this invention, the second heat insulation layer includes one or more of an MXene film layer, a cerium oxide film layer, copper foil, aluminum foil, or a stainless steel heat insulation layer. This second heat insulation layer can effectively insulate against radiant heat, thereby improving the heat insulation performance of the composite heat insulation pad and reducing the risk of thermal runaway in the battery device.

[0007] In some embodiments of this invention, the second heat insulation layer comprises multiple sub-layers, each of which is independently an MXene film layer, a cerium oxide film layer, a copper foil, an aluminum foil, or a stainless steel heat insulation layer. Thus, the second heat insulation layer formed by multiple sub-layers can also insulate against radiant heat, thereby improving the heat insulation performance of the composite heat insulation pad and reducing the risk of thermal runaway in the battery device.

[0008] In some embodiments of this invention, the thickness of the second heat insulation layer is 7μm-56μm. A second heat insulation layer of this thickness can effectively insulate against radiant heat without significantly increasing the thickness and cost of the composite heat insulation pad, thus facilitating the miniaturization of the battery device and controlling its cost.

[0009] In some embodiments of this invention, the thickness of the second heat insulation layer is 15μm-30μm. This is beneficial for further improving the overall performance of the battery device.

[0010] In some embodiments of this invention, the ceramic fiber insulation layer comprises one or more of a silicon oxide fiber layer, an alumina fiber layer, a mullite fiber layer, a silicon carbide fiber layer, or a silicon nitride fiber layer. Therefore, this ceramic fiber insulation layer can effectively isolate heat transfer in the form of conduction and convection.

[0011] In some embodiments of this invention, the thickness of the first heat insulation layer is 1mm-4mm. Therefore, the first heat insulation layer can isolate heat transfer in the form of conduction and convection.

[0012] In some embodiments of this invention, the number of the first heat insulation layer and the second heat insulation layer is the same, and the number of the first heat insulation layer is one, two, or three. Therefore, the composite heat insulation pad has good heat insulation performance, which helps reduce the risk of thermal runaway in the battery device.

[0013] In some embodiments of this invention, the composite heat insulation pad satisfies one of the following conditions: the number of the first heat insulation layer is 1, and the number of the second heat insulation layer is 2; the number of the first heat insulation layer is 2, and the number of the second heat insulation layer is 1; the number of the first heat insulation layer is 3, and the number of the second heat insulation layer is 2; or the number of the first heat insulation layer is 2, and the number of the second heat insulation layer is 3. Therefore, the composite heat insulation pad can effectively isolate heat transfer in the form of heat conduction, heat convection, and heat radiation, thereby helping to reduce the risk of thermal runaway in the battery device.

[0014] In another aspect, this utility model provides an electrical device. In some embodiments of this utility model, the electrical device includes the battery device described above. Therefore, the electrical device possesses all the features and advantages of the battery device described above, which will not be repeated here. In general, this electrical device is less prone to thermal runaway.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the alternative embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0017] Figure 1 This is a schematic diagram of a composite heat insulation pad according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0024] Figure 8 This is a schematic diagram of a composite heat insulation pad according to another embodiment of the present invention;

[0025] Figure 9 This is a schematic diagram of a battery device according to an embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of a battery device according to another embodiment of the present invention;

[0027] Figure 11 This is a schematic diagram of a battery cell according to one embodiment of the present invention;

[0028] Figure 12 yes Figure 11 An exploded view of a battery cell according to an embodiment of the present invention is shown.

[0029] Figure 13 This is a schematic diagram of a battery module according to an embodiment of the present invention;

[0030] Figure 14 This is a schematic diagram of a battery pack according to an embodiment of the present invention;

[0031] Figure 15 yes Figure 14 An exploded view of a battery pack according to an embodiment of the present invention is shown.

[0032] Figure 16 This is a schematic diagram of an electrical device according to an embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1 Battery cell; 11 Housing; 12 Electrode assembly; 13 Cover plate; 2 Battery module; 3 Battery pack; 31 Upper housing; 32 Lower housing; 100 Composite heat insulation pad; 110 First heat insulation layer; 120 Second heat insulation layer; 121 Sub-layer. Detailed Implementation

[0035] The embodiments of this utility model are described in detail below, examples of which are shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this utility model and are not intended to limit the subject matter of the claims.

[0036] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; unless otherwise stated, the values ​​of the parameters mentioned in this invention can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this invention).

[0037] The terms "comprising" and "having" and any variations thereof in the specification and claims of this utility model are open-ended expressions, meaning they include the contents specified in this utility model but do not exclude other aspects.

[0038] In the description of this utility model, all figures disclosed herein, whether or not the words "about" or "approximately" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by those skilled in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0039] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is understood that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this invention, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. "First feature" and "second feature" may include one or more of the feature.

[0041] In the description of this utility model, "multiple" means two or more.

[0042] In the description of this utility model, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are only examples and can be any technical feature connected by "and / or" in this utility model.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this utility model can be combined with each other to form new technical solutions.

[0044] Unless otherwise specified, all technical features and optional technical features of this utility model can be combined to form new technical solutions.

[0045] Unless otherwise specified, all steps of this invention can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] A battery device can contain multiple battery cells. One of these cells may experience thermal runaway due to overcharging or over-discharging, short circuits, impacts or vibrations, high temperatures, oxidation, mechanical abuse, or problems with internal components. This exothermic chain reaction can lead to overheating, fire, or even explosion—all signs of thermal runaway. To prevent heat dissipation, a common method is to use thermal insulation pads (made of ceramic fiber or aerogel) between adjacent battery cells to isolate heat conduction and convection, thereby reducing the surface temperature of adjacent battery cells.

[0047] Besides heat conduction and convection, heat transfer also includes heat radiation. Previous studies have focused on improving insulation materials to address heat conduction and convection, but the higher the actual temperature of heat transfer, the greater the proportion of radiative heat. In this application, a composite insulation pad is formed by combining a ceramic fiber insulation layer or an aerogel insulation layer with an insulation layer having low emissivity. The ceramic fiber insulation layer or aerogel insulation layer can effectively isolate heat conduction and convection, while the insulation layer with low emissivity can isolate most of the radiative heat, thereby reducing the total heat transfer between battery cells and lowering the cold surface temperature of battery cells adjacent to higher-temperature battery cells (for ease of understanding, the higher-temperature battery cell can be defined as the first cell, and the battery cell adjacent to it can be defined as the second cell; the cold surface temperature of the second cell refers to the temperature of the surface of the second cell away from the first cell), thus reducing the risk of thermal runaway in the battery device.

[0048] The battery device disclosed in this embodiment of the present invention may include a lithium-ion battery device (including multiple lithium-ion battery cells), and the battery device disclosed in this embodiment of the present invention can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0049] In one aspect, this utility model provides a battery device. In some embodiments of this utility model, reference is made to... Figure 9 and Figure 10 The battery device includes multiple battery cells 1, and a composite heat insulation pad 100 is provided between adjacent battery cells 1.

[0050] In some embodiments of this utility model, reference is made to Figures 1 to 10 The composite heat insulation pad 100 includes at least one first heat insulation layer 110 and at least one second heat insulation layer 120, the first heat insulation layer 110 and the second heat insulation layer 120 are alternately stacked, the first heat insulation layer 110 is a ceramic fiber heat insulation layer or an aerogel heat insulation layer, and the emissivity of the second heat insulation layer 120 is ≤0.3.

[0051] In some embodiments, the emissivity of the second heat insulation layer 120 may be ≤0.2. In some embodiments, the emissivity of the second heat insulation layer 120 may be approximately 0.1, 0.2, etc. In some embodiments, the emissivity of the second heat insulation layer 120 may be 0.1-0.15. In some embodiments, the emissivity of the second heat insulation layer may be 0.2-0.3.

[0052] For an object that is not completely opaque, reflectivity + absorptivity (emissivity) + transmissivity = 1; but for an opaque object, reflectivity + absorptivity (emissivity) = 1. According to the law of conservation of heat, absorbed heat = radiated heat, so the less heat absorbed, the more heat reflected, and the less heat emitted (i.e., radiated heat).

[0053] In some embodiments, the emissivity of an object can be tested using the radiation energy method, which determines the emissivity by measuring the energy radiated by the object. Specifically, the object is placed in a stable temperature environment, its radiated energy is measured using a radiometer, and the result is compared with a standard object whose emissivity is known. The emissivity of the object is then calculated using physical formulas.

[0054] In some embodiments, the emissivity of an object can be tested using infrared spectroscopy. Specifically, an infrared spectrometer is used to measure the infrared radiation intensity of the object at different wavelengths, and the emissivity of the object is calculated by analyzing the relationship between radiation intensity and wavelength in the spectrum.

[0055] In some embodiments, the emissivity of an object can be tested using thermal imaging. The principle is as follows: a thermal imager is used to measure the surface temperature distribution of the object, and the emissivity is calculated using the blackbody radiation formula. The steps are as follows: 1. Heat the object to a stable temperature; 2. Use a thermal imager to measure the surface temperature distribution; 3. Calculate the emissivity according to the blackbody radiation formula.

[0056] The first insulation layer 110 is a ceramic fiber insulation layer or an aerogel insulation layer, which can effectively isolate heat conduction and heat convection. The second insulation layer 120 has a low emissivity and can isolate most of the radiant heat (electromagnetic waves in the infrared band). By using the second insulation layer 120 and the first insulation layer 110 in a structural composite, the total heat transfer can be reduced, and the cold surface temperature of the battery cell adjacent to the higher-temperature battery cell can be lowered (for ease of understanding, the higher-temperature battery cell can be defined as the first cell, and the battery cell adjacent to it can be defined as the second cell. The cold surface temperature of the second cell refers to the temperature of the surface of the second cell away from the first cell). This reduces the risk of thermal runaway of the battery device to at least a certain extent.

[0057] In some embodiments of this utility model, reference is made to Figure 1 , Figure 4 , Figure 7 and Figure 10 The number of the first heat insulation layer 110 and the second heat insulation layer 120 can be the same. In some embodiments of this utility model, refer to Figure 1 and Figure 10 The number of the first heat insulation layer 110 and the number of the second heat insulation layer 120 are both one, and the second heat insulation layer 120 is located on one side of the first heat insulation layer 110. In some embodiments of this utility model, refer to Figure 4 The number of the first heat insulation layer 110 and the number of the second heat insulation layer 120 are both two. In some embodiments of this utility model, refer to Figure 7 The first heat insulation layer 110 and the second heat insulation layer 120 each have three layers. Therefore, the composite heat insulation pad 100 has good heat insulation performance. Placing the composite heat insulation pad between adjacent battery cells helps reduce the risk of thermal runaway in the battery device.

[0058] In some embodiments of this utility model, reference is made to Figure 2 , Figure 3 , Figure 5 , Figure 6 , Figure 8 and Figure 9 The number of the first insulation layer 110 and the second insulation layer 120 can be different. Thus, the composite insulation pad 100 can effectively isolate heat transfer in the form of heat conduction, heat convection and heat radiation.

[0059] In some embodiments of this utility model, reference is made to Figure 2 There is one first heat insulation layer 110 and two second heat insulation layers 120. The first heat insulation layer 110 is located between the two second heat insulation layers 120, forming a "sandwich" structure.

[0060] In some embodiments of this utility model, reference is made to Figure 3 and Figure 9 There are two first heat insulation layers 110 and one second heat insulation layer 120. The second heat insulation layer 120 is located between the two first heat insulation layers 110, forming a "sandwich" structure.

[0061] In some embodiments of this utility model, reference is made to Figure 5 There are two first insulation layers 110 and three second insulation layers 120.

[0062] In some embodiments of this utility model, reference is made to Figure 6 There are 3 first insulation layers 110 and 2 second insulation layers 120.

[0063] In some embodiments of this invention, the first heat insulation layer 110 can be a ceramic fiber heat insulation layer, which may include one or more of the following: a silicon oxide fiber layer, an alumina fiber layer, a mullite fiber layer (the main components are alumina and silicon dioxide, and may also contain other substances such as zirconium oxide), a silicon carbide fiber layer, or a silicon nitride fiber layer. The aforementioned ceramic fiber heat insulation layer can effectively isolate heat transfer through both conduction and convection, thereby improving the heat insulation performance of the composite heat insulation pad and reducing the risk of thermal runaway in the battery device.

[0064] In some embodiments of this invention, the first heat insulation layer 110 can be a ceramic fiber heat insulation layer, which can be a silicon oxide fiber layer, an alumina fiber layer, a mullite fiber layer, a silicon carbide fiber layer, or a silicon nitride fiber layer. The aforementioned ceramic fiber heat insulation layer can effectively isolate heat transfer through conduction and convection, thereby reducing the heat transferred from higher-temperature battery cells to adjacent battery cells via conduction and convection.

[0065] In some embodiments of this invention, the first thermal insulation layer 110 can be an aerogel thermal insulation layer. In some embodiments, the main material of the aerogel thermal insulation layer can be silica aerogel. Silica aerogel can be formed into nanoscale primary particles through a sol-gel process via hydrolysis and condensation reaction, and then aggregated to form a three-dimensional network structure. Silica aerogel has characteristics such as ultra-low thermal conductivity, high porosity, and low density, which can effectively prevent heat conduction.

[0066] It should be noted that when the composite heat insulation pad 100 has multiple first heat insulation layers 110, the materials of the multiple first heat insulation layers 110 can be the same or different. For example, in some embodiments, the multiple first heat insulation layers 110 can all be ceramic heat insulation layers or aerogel heat insulation layers.

[0067] In some embodiments of this utility model, reference is made to Figures 1 to 8 The thickness h1 of the first heat insulation layer 110 can be 1mm-4mm, for example, the thickness h1 of the first heat insulation layer 110 can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc. Therefore, the first heat insulation layer of the above thickness can effectively isolate heat transfer in the form of heat conduction and heat convection.

[0068] It should be noted that when the composite heat insulation pad 100 has multiple first heat insulation layers 110, the thickness of the multiple first heat insulation pads 110 can be the same or different.

[0069] In some embodiments of this utility model, reference is made to Figures 1 to 8 The thickness h2 of the second heat insulation layer 120 can be 7μm-56μm. For example, the thickness h2 of the second heat insulation layer 120 can be 7μm, 10μm, 14μm, 15μm, 20μm, 22μm, 26μm, 30μm, 35μm, 40μm, 45μm, 50μm, 56μm, etc. The second heat insulation layer 120 with the above-mentioned thickness can play a good role in isolating radiant heat, reducing the heat transferred from the high-temperature battery cells to adjacent battery cells through the radiation of infrared electromagnetic waves (infrared light), which helps to reduce the risk of thermal runaway of the battery device; and the above-mentioned thickness of the second heat insulation layer does not significantly increase the cost and thickness of the composite heat insulation pad.

[0070] In some embodiments of this invention, the thickness h2 of the second heat insulation layer 120 can be 15μm-30μm. Setting the thickness of the second heat insulation layer within the above range is beneficial for reducing the risk of thermal runaway in the battery device while better controlling the cost and thickness of the battery device.

[0071] In some embodiments of this invention, the second heat insulation layer 120 may include one or more of an MXene film, a cerium oxide (CeO2) film, copper foil, aluminum foil, or a stainless steel heat insulation layer. Therefore, the second heat insulation layer has a low emissivity, which is beneficial for isolating thermal radiation and reducing the total heat transfer between adjacent battery cells, thereby helping to reduce the risk of thermal runaway in the battery device.

[0072] In some embodiments of this invention, the second heat insulation layer 120 can be an MXene film, a cerium oxide (CeO2) film, copper foil, aluminum foil, or a stainless steel heat insulation layer. The aforementioned second heat insulation layer 120 can effectively insulate against radiant heat, thereby improving the heat insulation performance of the composite heat insulation pad and reducing the risk of thermal runaway in the battery device.

[0073] It should be noted that when the composite heat insulation pad 100 has multiple second heat insulation layers 120, the materials of the multiple second heat insulation layers 120 can be the same or different.

[0074] The emissivity of the second insulation layer made of different materials is shown in Table 1 below.

[0075] Table 1

[0076] type Cu foil Al foil MXene <![CDATA[CeO2]]> Stainless steel Emission rate ≤0.1 ～0.1 ～0.2 0.2-0.3 0.1-0.25

[0077] The emissivity of copper foil is ≤0.1, aluminum foil is around 0.1, and stainless steel is 0.1-0.25. MXene materials have emissivity close to that of metallic materials. CeO2 has an emissivity of 0.2-0.3. Materials with low emissivity have good infrared shielding effects. It should be noted that the emissivity of copper and aluminum foil is affected by the surface condition of the material (e.g., polishing state), and the emissivity of aluminum or copper foil will differ under different conditions. In some embodiments, the emissivity of aluminum foil may be lower than that of copper foil; in other embodiments, the emissivity of aluminum foil may be higher than that of copper foil.

[0078] The second heat insulation layer of the aforementioned materials all have low emissivity, which can effectively block infrared electromagnetic waves and prevent them from being transmitted from the higher-temperature battery cells to adjacent battery cells. The second heat insulation layer of these materials blocks the energy radiated by infrared electromagnetic waves with wavelengths of 3-14 μm; at high temperatures (300-600℃), according to Wien's displacement law, the second heat insulation layer primarily blocks infrared electromagnetic waves in the 3-5 μm band.

[0079] MXene, cerium oxide (CeO2), copper, aluminum, and stainless steel are all infrared shielding materials with low emissivity, which can effectively insulate against radiant heat. In some embodiments of this invention, the aforementioned infrared shielding materials can be formed into a film and attached to the first heat insulation layer to form a composite heat insulation pad. In other embodiments of this invention, the aforementioned infrared shielding materials can also be directly sprayed onto the first heat insulation layer to form a composite heat insulation pad. Using the above methods, a second heat insulation layer with uniform thickness and high surface density can be prepared, which is beneficial for improving the heat insulation effect of the composite heat insulation pad.

[0080] In some specific embodiments, copper foil, aluminum foil, or stainless steel insulation layers can be adhered to ceramic fiber insulation layers or aerogel insulation layers to form a composite insulation pad. Specifically, copper foil, aluminum foil, or stainless steel insulation layers can be adhered to ceramic fiber insulation layers or aerogel insulation layers using an adhesive layer. The specific material and thickness of the adhesive layer are not particularly limited in this invention, and those skilled in the art can select according to actual needs. In other specific embodiments, powdered MXene and / or cerium oxide (CeO2) can be sprayed onto ceramic fiber insulation layers or aerogel insulation layers to form a composite insulation pad. In still other specific embodiments, a dispersion of MXene and / or cerium oxide (CeO2) can be sprayed onto ceramic fiber insulation layers or aerogel insulation layers to form a composite insulation pad.

[0081] In some embodiments, the second heat insulation layer 120 may be a polished copper foil or a polished aluminum foil. After polishing, the copper foil or aluminum foil becomes denser and the surface roughness is significantly reduced. The polished copper foil or aluminum foil has a higher reflectivity and can reflect more infrared electromagnetic waves back, thereby reducing the penetration and absorption of radiant heat.

[0082] MXene is a novel type of two-dimensional material composed of transition metal carbides, nitrides, or carbonitrides. MXene is a class of novel two-dimensional nanomaterials obtained by etching away the alumina (A) element from the layered ceramic MAX phase. The chemical formula of MXene is usually represented as M. n+1 X n T m In this system, "M" represents a transition metal element (e.g., chromium, molybdenum, manganese, iron, cobalt, copper, aluminum, silver, nickel, palladium, platinum, ruthenium, etc.), "X" represents carbon or nitrogen, and "T" represents a functional group on the surface of the material, such as hydroxyl (-OH), halogen groups (-F, -Cl, etc.).

[0083] In some embodiments of this invention, the MXene film can be Ti3C2T. m Membrane.

[0084] In some embodiments, the emissivity of the MXene film is approximately 0.2.

[0085] In some embodiments of this utility model, reference is made to Figure 8 The second insulation layer 120 may include multiple sub-layers 121, each of which is independently an MXene film, a cerium oxide film, a copper foil, an aluminum foil, or a stainless steel insulation layer. Thus, the second insulation layer 120 formed by multiple sub-layers 121 can also serve to insulate radiant heat, thereby improving the insulation performance of the composite insulation pad 100.

[0086] In some specific embodiments, the multiple sub-layers 121 may be the same, and may be MXene film, cerium oxide film, copper foil, aluminum foil or stainless steel insulation layer.

[0087] In other embodiments, the multiple sub-layers 121 may be different. The second insulation layer 120 includes sub-layers 121 of different materials, which can better block infrared electromagnetic waves of different wavelength ranges, thereby helping to further improve the insulation performance of the composite insulation pad.

[0088] In some embodiments of this utility model, reference is made to Figure 9 The battery device may include two battery cells and a composite heat insulation pad 100, with the composite heat insulation pad 100 located between the two battery cells.

[0089] In other embodiments of this utility model, reference is made to Figure 10 The battery device may include 3 battery cells and 2 composite heat insulation pads 100, and a composite heat insulation pad 100 is provided between any 2 adjacent battery cells.

[0090] It should be noted that when the battery device includes three or more battery cells, placing a composite heat insulation pad 100 between two of the battery cells can reduce the risk of thermal runaway to a certain extent. Of course, placing a composite heat insulation pad 100 between any adjacent battery cells is more conducive to reducing the risk of thermal runaway.

[0091] In some embodiments of this invention, the battery cell 1 can be a lithium-ion battery cell. In other embodiments of this invention, the battery cell 1 can be a sodium-ion battery cell.

[0092] Typically, a battery cell 1 includes a positive electrode, a negative electrode, an electrolyte, and a separator. During the charging and discharging process of battery cell 1, active metal ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0093] In some embodiments, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including a positive active material.

[0094] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0095] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0096] In some embodiments of this invention, the battery cell 1 can be a lithium-ion battery cell, and the positive electrode active material may include lithium iron phosphate (LiFePO4), lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2).

[0097] During the charging and discharging process, battery cell 1 undergoes Li insertion / extraction and consumption, resulting in different molar contents of Li in battery cell 1 at different discharge states. In the examples of positive electrode active materials in this invention, the molar contents of Li refer to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery cell, the molar contents of Li will change after charge-discharge cycles.

[0098] In the examples of positive electrode active materials in this invention, the molar content of oxygen is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of oxygen will fluctuate.

[0099] In some embodiments of this invention, the positive electrode active material layer may optionally include a binder. As an example, the binder in the positive electrode active material layer may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0100] In some embodiments of this invention, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent in the positive electrode active material layer may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0101] In some embodiments of this utility model, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0102] In some embodiments of this utility model, the negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector.

[0103] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0104] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0105] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, tin-based materials, and lithium titanate, etc. Tin-based materials may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, this invention is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used.

[0106] In some embodiments, the negative electrode active material layer may optionally include a negative electrode binder. The negative electrode binder in the negative electrode active material layer may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0107] In some embodiments, the negative electrode active material layer may optionally include a conductive agent. The conductive agent in the negative electrode active material layer may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0108] In some embodiments, the negative electrode active material layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0109] In some embodiments, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, conductive agent, negative electrode binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0110] In some embodiments of this invention, the electrolyte may be liquid, gel, or solid.

[0111] In some embodiments of this invention, the electrolyte is an electrolyte solution. In some specific embodiments, the electrolyte solution includes an electrolyte salt and a solvent.

[0112] In some embodiments of this invention, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(trifluoromethanesulfonyl)imide, lithium fluorosulfonate, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0113] In some embodiments of this invention, the solvent may include at least one of ethylene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate, butene carbonate, dimethyl carbonate, methyl propyl carbonate, dipropyl carbonate, ethyl propyl carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, and γ-butyrolactone.

[0114] In some embodiments of this invention, in addition to electrolyte salts and solvents, the electrolyte may also include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0115] In some embodiments, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly by a winding process or a stacking process.

[0116] In some embodiments, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above. In some embodiments, the outer packaging of the battery cell may be a rigid shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the battery cell may also be a flexible package, such as a pouch. The material of the flexible package may be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0117] This invention does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 11 Here is a square-structured battery cell 1 as an example.

[0118] In some embodiments, refer to Figure 12The outer packaging may include a housing 11 and a cover plate 13. The housing 11 may include a bottom plate and side plates connected to the bottom plate, the bottom plate and side plates forming a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the cover plate 13 can be placed over the opening to close the receiving cavity. The positive electrode sheet, negative electrode sheet, and separator can be formed into an electrode assembly 12 by a winding process or a stacking process. The electrode assembly 12 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 12. The number of electrode assemblies 12 contained in a single battery cell 1 can be one or more, which can be selected by those skilled in the art according to specific practical needs.

[0119] In some embodiments of this invention, the battery device may be a battery module. (See reference...) Figure 13 The battery module 2 includes multiple battery cells 1, and the composite heat insulation pad 100 described above is disposed between adjacent battery cells 1. Figure 13 (Not shown in the image). Therefore, this composite thermal insulation pad can effectively isolate heat transfer in the form of heat conduction, heat convection and heat radiation, thereby reducing the total heat transfer between adjacent battery cells, lowering the cold surface temperature of battery cells adjacent to those with higher temperatures, and thus at least to some extent avoiding the risk of thermal runaway of the battery module.

[0120] It should be noted that the specific number of battery cells contained in the battery module is not particularly limited, and those skilled in the art can select the appropriate number based on the application and capacity of the battery module.

[0121] Figure 13 This is battery module 2 as an example. (See reference...) Figure 13 In battery module 2, multiple battery cells 1 can be arranged sequentially along the length of battery module 2. Of course, they can also be arranged in any other way. Furthermore, these multiple battery cells 1 can be fixed in place using fasteners.

[0122] Optionally, the battery module 2 may also include a housing with a receiving space in which multiple battery cells 1 are received.

[0123] In some other embodiments of this invention, the battery device can be a battery pack, which may include multiple battery cells, with the aforementioned composite heat insulation pad disposed between adjacent battery cells. Therefore, the battery pack is less prone to thermal runaway.

[0124] In some embodiments of this invention, the battery pack may include the battery module described above. Therefore, the battery pack possesses all the features and advantages of the battery module described above, which will not be repeated here. In general, this battery pack is less prone to thermal runaway.

[0125] In some embodiments, the battery pack may contain one or more battery modules, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery pack.

[0126] Figure 14 and Figure 15 This is battery pack 3 as an example. (See reference...) Figure 14 and Figure 15 The battery pack 3 may include a battery box and multiple battery modules 2 disposed within the battery box. The battery box includes an upper box 31 and a lower box 32, with the upper box 31 covering the lower box 32 to form a closed space for accommodating the battery modules 2. The multiple battery modules 2 can be arranged in any manner within the battery box.

[0127] In some embodiments of this invention, multiple battery cells can be directly assembled into a battery pack, eliminating the need for a battery module structure and improving the battery's energy density. The battery comprises multiple battery cells, and the specific number of battery cells can be selected by those skilled in the art based on the application and capacity of the battery pack.

[0128] In some embodiments, the battery device (e.g., battery module 2 or battery pack 3) can be the power source of the electrical device or the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0129] It should be noted that electrical devices can select battery modules or battery packs according to their usage needs.

[0130] In another aspect, this utility model provides an electrical device. In some embodiments of this utility model, the electrical device includes the battery device described above. Therefore, the electrical device possesses all the features and advantages of the battery device described above, which will not be repeated here.

[0131] Figure 16 This is an example of an electrical device. This device can be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the secondary battery for this device, a battery pack or battery module can be used.

[0132] The present invention will be described below through specific embodiments. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0133] Example 1

[0134] Take two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material), and attach a polished aluminum foil with a thickness of 26 μm between the two ceramic fiber heat insulation pads to make a "sandwich" sandwich structure to obtain a composite heat insulation pad.

[0135] Example 2

[0136] Two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material) are taken, and three polished copper foils with a thickness of 7 μm are attached between the two ceramic fiber heat insulation pads to form a "sandwich" sandwich structure, thus obtaining a composite heat insulation pad.

[0137] Example 3

[0138] Take two ceramic fiber heat insulation pads with a thickness of 1.2 mm (using SiO2 fiber as the main material), and spray a 22 μm thick MXene coating (material is Ti3C2T) onto one surface of one of the ceramic fiber heat insulation pads. x In this process, "T" represents a functional group on the material surface, such as hydroxyl (-OH), halogen groups (-F, -Cl), etc. Another ceramic fiber insulation pad is then attached to the MXene coating surface, with the MXene coating positioned between the two ceramic fiber insulation pads, resulting in a composite insulation pad. The MXene coating uses a product from Xinxi Technology (single-layer Ti3C2T). x Dispersion (molecular weight: 167.6; purity: ≥99.9%) is sprayed.

[0139] Example 4

[0140] Take two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material), spray a 30 μm thick CeO2 coating on one surface of one of the ceramic fiber heat insulation pads, and then attach the other ceramic fiber heat insulation pad to the CeO2 coating surface, so that the CeO2 coating is located between the two ceramic fiber heat insulation pads to obtain a composite heat insulation pad.

[0141] Example 5

[0142] Take two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material), and attach a polished copper foil with a thickness of 7 μm between the two ceramic fiber heat insulation pads to make a "sandwich" sandwich structure to obtain a composite heat insulation pad.

[0143] Example 6

[0144] Take two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material), and attach two polished copper foils with a thickness of 7 μm between the two ceramic fiber heat insulation pads to make a "sandwich" sandwich structure to obtain a composite heat insulation pad.

[0145] Example 7

[0146] Two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material) are taken, and six polished copper foils with a thickness of 7 μm are attached between the two ceramic fiber heat insulation pads to form a "sandwich" sandwich structure, thus obtaining a composite heat insulation pad.

[0147] Example 8

[0148] Two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material) are taken, and eight polished copper foils with a thickness of 7 μm are attached between the two ceramic fiber heat insulation pads to form a "sandwich" sandwich structure, thus obtaining a composite heat insulation pad.

[0149] Comparative Example 1

[0150] Two ceramic fiber heat insulation pads with a thickness of 1.2 mm (using SiO2 fiber as the main material) were bonded together to obtain a composite heat insulation pad, which served as the first control group.

[0151] In addition, two ceramic fiber heat insulation pads with a thickness of 1.2 mm (with SiO2 fiber as the main material) were bonded together to obtain a composite heat insulation pad, which served as the second control group.

[0152] The composite thermal insulation pads of the examples and the control group were subjected to relevant hot-table tests, and the test results are recorded in Table 2.

[0153] The testing instruments are as follows:

[0154] SET High Temperature Heating Stage (Shenzhen Fan & Hang Electronic Technology Co., Ltd.);

[0155] Multi-channel storage recorder: HIOKI: LR8431-30 (HIOKI Measurement Co., Ltd., Japan);

[0156] Temperature sensing cable: PK-K / GO.255*2.5m (Ningde Sirong Electronic Equipment Co., Ltd.).

[0157] The test conditions are as follows:

[0158] The upper layer of the composite insulation pad has three temperature sensing lines, and the lower layer of the insulation pad that contacts the hot table has three more temperature sensing lines. The positions of the upper and lower temperature sensing lines are mirror-symmetrical, which makes it easy to compare the temperature difference between the cold and hot sides.

[0159] The hot plate was heated to 600℃, and the test time was 30 minutes (the temperature was heated to 600℃, and then a composite heat insulation pad was placed to simulate the actual battery cell conditions).

[0160] A 1.5kg pressure pad is placed on the composite heat insulation pad, and a 3mm thick heat insulation pad (the heat insulation pad covers the large surface of the pressure pad to prevent the pressure pad from contacting the object being measured and to allow it to dissipate heat) is used to isolate the upper temperature sensing wire and the pressure pad.

[0161] Table 2

[0162]

[0163]

[0164] The average temperature difference between the cold and hot sides in the first and second control groups was 200.7℃ and 200.3℃, respectively. The average value of 200.5℃ was taken as the average temperature difference between the cold and hot sides in Comparative Example 1.

[0165] Compared with Comparative Example 1, the average temperature difference between the hot and cold surfaces of the composite thermal insulation pad (with MXene material as the middle layer) in Example 3 increased by 15.8°C, and the average temperature difference between the hot and cold surfaces of the composite thermal insulation pad (with CeO2 material as the middle layer) in Example 4 increased by 14.6°C.

[0166] Compared with Comparative Example 1, the average temperature difference between the hot and cold surfaces of the composite heat insulation pad (with a 26 μm thick Al foil interlayer) in Example 1 increased by about 37.2°C.

[0167] Compared with Comparative Example 1, the average temperature difference between the hot and cold surfaces of the composite heat insulation pad (with a 21 μm thick Cu foil interlayer) in Example 2 increased by about 35.7°C.

[0168] Compared with Comparative Example 1, Examples 1-4 generally show the following pattern: as the emissivity of the intermediate interlayer material decreases, the infrared shielding effect is better, and the temperature difference shows an upward trend.

[0169] Compared with Comparative Example 1, the average temperature difference between the hot and cold surfaces of the composite thermal insulation pads in Examples 5-8 increased significantly. Test data from Examples 2 and 6-8 show that as the interlayer thickness increases, the average temperature difference between the hot and cold surfaces initially shows an upward trend, then tends to stabilize, fluctuating within a certain range.

[0170] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," and "other embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0171] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A battery device, characterized in that, It includes multiple battery cells, and a composite heat insulation pad is disposed between adjacent battery cells. The composite heat insulation pad includes at least one first heat insulation layer and at least one second heat insulation layer. The first heat insulation layer and the second heat insulation layer are alternately stacked. The first heat insulation layer is a ceramic fiber heat insulation layer or an aerogel heat insulation layer. The emissivity of the second heat insulation layer is ≤0.

3.

2. The battery device according to claim 1, characterized in that, The second insulation layer includes one or more of the following: MXene film, cerium oxide film, copper foil, aluminum foil, or stainless steel insulation layer.

3. The battery device according to claim 1, characterized in that, The second insulation layer comprises multiple sub-layers, each of which is independently an MXene film layer, a cerium oxide film layer, a copper foil, an aluminum foil, or a stainless steel insulation layer.

4. The battery device according to any one of claims 1-3, characterized in that, The thickness of the second heat insulation layer is 7μm-56μm.

5. The battery device according to claim 4, characterized in that, The thickness of the second heat insulation layer is 15μm-30μm.

6. The battery device according to any one of claims 1-3, characterized in that, The ceramic fiber insulation layer includes one or more of the following: silicon oxide fiber layer, alumina fiber layer, mullite fiber layer, silicon carbide fiber layer, or silicon nitride fiber layer.

7. The battery device according to any one of claims 1-3, characterized in that, The thickness of the first heat insulation layer is 1mm-4mm.

8. The battery device according to any one of claims 1-3, characterized in that, The number of the first insulation layer and the second insulation layer is the same, and the number of the first insulation layer is 1, 2 or 3.

9. The battery device according to any one of claims 1-3, characterized in that, The composite thermal insulation pad meets one of the following conditions: The number of the first heat insulation layer is 1, and the number of the second heat insulation layer is 2; The number of the first heat insulation layer is 2, and the number of the second heat insulation layer is 1; The number of the first heat insulation layer is 3, and the number of the second heat insulation layer is 2; The number of the first heat insulation layer is 2, and the number of the second heat insulation layer is 3.

10. An electrical device, characterized in that, The battery device includes any one of claims 1-9.

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