Thermal insulation material and preparation method thereof, and electronic equipment

Abstract

The present application provides a thermal insulation material and a preparation method thereof, and an electronic device, and relates to the field of terminal technology. The thermal insulation material includes: an ice crystal base, in which ice crystals are densely and continuously distributed along a first plane; an ice crystal unit, in which the ice crystal unit includes at least one ice crystal column, which extends in a direction perpendicular to the first plane, and in which ice crystals in the ice crystal column that are in contact with the ice crystal base are connected to ice crystals in the ice crystal base, and the ice crystal column has a plurality of ice crystal branches, and adjacent ice crystal branches are separated and arranged at intervals, and the extension direction of the ice crystal branches is different from the extension direction of the ice crystal column. As a result, the thermal insulation material can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities, and when heated by an external heat source, it can exhibit excellent thermal insulation properties, and at the same time, it also has excellent compressibility.

Description

Technical Field

[0001] The present application relates to the field of terminal technology, and in particular to a thermal insulation material and a preparation method thereof, and an electronic device. Background Art

[0002] With the development of science and technology, the application of consumer electronic terminal products, such as mobile phones, is becoming more and more popular. Traditional consumer electronic terminal products usually have local hot spots at the contact position between the local protrusion of the battery's flexible printed circuit (FPC) and the battery cover, the contact position between the mainboard bracket and the battery cover, and the contact position between the board to board (BTB) bracket and the battery cover, which seriously affects the charging speed and thermal experience of consumer electronic terminal products.

[0003] At present, thermal insulation is often performed by attaching thermal insulation foam materials or thermal insulation foam materials to the above-mentioned positions, and utilizing the high porosity of the thermal insulation foam materials or thermal insulation foam materials to reduce air conduction and convection. However, the closed pores of the thermal insulation foam materials or thermal insulation foam materials are isotropic, and the solid heat conduction through the pore wall is high. The thermal insulation effect after compression is poor, and the mechanical reliability is also poor. In addition, ceramic aerogel materials are also used for thermal insulation. However, the mechanical properties of ceramic aerogel materials are also poor, and most ceramic aerogel materials are prone to slag when compressed.

[0004] Therefore, it is urgent to provide a new type of thermal insulation material to solve the above problems. Summary of the invention

[0005] The embodiments of the present application provide a thermal insulation material and a preparation method thereof, and an electronic device. The thermal insulation material is an anisotropic aerogel material that can withstand high temperatures and maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties. At the same time, the thermal insulation aerogel material has excellent compressibility.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, a thermal insulation material is provided, which includes: an ice crystal base, which is actually a three-dimensional structure, and ice crystals in the ice crystal base are densely and continuously distributed at least along the xz plane; and an ice crystal unit, which includes at least one ice crystal column, and the ice crystal column extends along the growth direction of the ice crystals, and the ice crystals in the ice crystal column that are in contact with the ice crystal base are connected to the ice crystals in the ice crystal base, and the ice crystal column has a plurality of ice crystal branches, and adjacent ice crystal branches are separated and arranged at intervals, and the extension direction of the ice crystal branches is different from the extension direction of the ice crystal column.

[0008] An embodiment of the present application provides a thermal insulation material, which is an anisotropic aerogel material. The microstructure of the aerogel material is similar to the microstructure of penguin feathers, and thus has a thermal insulation effect similar to that of penguin feathers. It can withstand high temperatures and maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties. At the same time, the thermal insulation aerogel material has excellent compressibility.

[0009] In a possible implementation of the first aspect, the ice crystal unit includes a plurality of ice crystal columns, and an orientation channel is provided between adjacent ice crystal columns. The orientation channel is extended and arranged along a growth direction of the ice crystals and sandwiched between adjacent ice crystal columns, and ice crystal branches are distributed in the orientation channel.

[0010] In this implementation, the aerogel material can have better thermal insulation and compressibility.

[0011] In a possible implementation manner of the first aspect, an angle between an extension direction of each ice crystal branch and an extension direction of the ice crystal column is an acute angle.

[0012] In this implementation, the heat insulation effect of the aerogel material is better.

[0013] In a possible implementation of the first aspect, each ligament has a plurality of discrete and spaced-apart pores inside.

[0014] In this implementation, the thermal insulation of the aerogel material can be improved.

[0015] In a possible implementation manner of the first aspect, extension directions of all ice crystal columns are parallel to each other.

[0016] In this implementation, the aerogel is composed of long branches arranged in a directional manner, and when heated by an external heat source, the aerogel material can exhibit excellent thermal insulation and compressibility.

[0017] In a possible implementation manner of the first aspect, extension directions of all ice crystal branches are parallel to each other.

[0018] In this implementation, the aerogel is composed of parallel branches, and when heated by an external heat source, the aerogel material can exhibit excellent thermal insulation and compressibility.

[0019] In a possible implementation of the first aspect, extension directions of all ice crystal columns are parallel to each other, and extension directions of all ice crystal branches are parallel to each other.

[0020] In this implementation, the aerogel is composed of long branches and parallel branches that are arranged in a directional manner. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation and compressibility.

[0021] In a possible implementation manner of the first aspect, the multiple ice crystal branches on each ice crystal column are arranged in a circle around the ice crystal column.

[0022] In this implementation, the thermal insulation and compressibility of the aerogel material can be improved.

[0023] In a possible implementation of the first aspect, the aerogel material that has undergone freeze-thaw cycles and heat treatments is ultimately in a solid state.

[0024] In this implementation, the solid thermal insulation aerogel material can be adhered to the required bonding position by pressure-sensitive adhesive, which is simple and easy to operate.

[0025] In a possible implementation manner of the first aspect, an angle between an extension direction of the ice crystal branch and an extension direction of the ice crystal column is an acute angle.

[0026] In this implementation, the thermal insulation aerogel material has good thermal insulation and compressibility.

[0027] In a possible implementation of the first aspect, a width of the orientation channel parallel to the xz plane ranges from 40 µm to 60 µm.

[0028] In this implementation, the thermal insulation aerogel material has good thermal insulation and compressibility.

[0029] In a possible implementation of the first aspect, each orientation channel has a plurality of discrete and spaced holes, forming abundant ligaments in the porous orientation channel.

[0030] In this implementation, the thermal insulation aerogel material has good thermal insulation and compressibility.

[0031] In a possible implementation of the first aspect, the abundant ligaments can divide the porous oriented channels into microchannels with a width ranging from 10µm to 20µm in the z direction at an angle of about 60°.

[0032] In this implementation, the thermal insulation aerogel material has good thermal insulation and compressibility.

[0033] In a possible implementation of the first aspect, an angle between an extension direction of each ice crystal branch and an extension direction of the ice crystal column ranges from 50° to 80°.

[0034] In this implementation, the thermal insulation effect of the aerogel material is improved.

[0035] In a possible implementation manner of the first aspect, an angle between an extension direction of each ice crystal branch and an extension direction of the ice crystal column is about 60°.

[0036] In this implementation, aerogel material has the best thermal insulation properties.

[0037] In a possible implementation of the first aspect, each ligament has a plurality of smaller pores with a size less than 1 µm inside, and adjacent pores are discrete and spaced apart.

[0038] In this implementation, the thermal insulation and compressibility of the aerogel material can be improved.

[0039] In a possible implementation of the first aspect, the shape of the orthographic projection of the pores on the ice crystal dendrites on the xz plane is a circle, and the diameter of the circle is less than 1 µm.

[0040] In this implementation, the thermal insulation and compressibility of the aerogel material can be improved.

[0041] In a second aspect, an electronic device is provided, comprising the thermal insulation material as in the first aspect or any possible implementation of the first aspect.

[0042] An embodiment of the present application provides an electronic device, including an aerogel material imitating a penguin feather structure. Since the aerogel material can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, when heated by an external heat source, the aerogel material can exhibit excellent heat insulation and heat resistance. The aerogel material also has excellent compressibility, thereby enabling the electronic device to have a local heat insulation effect, reducing or avoiding the generation of local hot spots, improving the charging speed and thermal experience, and the overall performance of the electronic device is good.

[0043] In a possible implementation of the second aspect, the electronic device also includes a battery, a battery cover and an adhesive, the battery cover has a first surface, the insulation material is adhered to the first surface by the adhesive, and the first surface is used to face the battery when the battery and the battery cover are both installed in the electronic device.

[0044] In this implementation, the insulating aerogel material is adhered to the inner surface of the battery cover with the help of an adhesive and assembled into a complete machine, thereby preventing these structures from directly contacting the battery cover to transfer heat, reducing or avoiding the generation of local hot spots, avoiding heat loss, and improving the charging speed and thermal experience; at the same time, since the insulating aerogel material has excellent compressibility, it can be placed in these positions and make the electronic equipment miniaturized; in addition, the adhesive has good bonding strength with the insulating aerogel material and the battery cover, and the aerogel can be adhered to the inner surface of the battery cover using a pressure-sensitive adhesive.

[0045] In a possible implementation manner of the second aspect, the adhesive may be a pressure-sensitive adhesive, and the thermal insulation aerogel material is adhered to the electronic device via the pressure-sensitive adhesive.

[0046] In this implementation, the pressure sensitive adhesive is readily available.

[0047] In a possible implementation of the second aspect, a layer of pressure-sensitive adhesive is first brushed or directly adhered to the surface of the prepared solid thermal insulation aerogel material, and then cut into a size that matches the size of the hot spot position; during the assembly process, the thermal insulation aerogel material is adhered to the surface of the battery cover corresponding to the battery position to obtain a battery cover assembly; finally, this integrated battery cover assembly is assembled with other components to obtain a complete machine, and a consumer electronic terminal product is obtained with the help of this thermal insulation material.

[0048] This implementation is simple and easy to operate.

[0049] In a possible implementation of the second aspect, the heat insulating aerogel material is adhered to the contact position between the battery FPC protrusion and the inner surface of the battery cover by a pressure-sensitive adhesive.

[0050] In this implementation, the insulating aerogel material can withstand high temperatures, maintain a constant temperature, and is lightweight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties, reducing or avoiding the appearance of local hot spots on the battery FPC protrusion and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0051] In a possible implementation of the second aspect, the heat insulating aerogel material is adhered to the contact position between the mainboard bracket and the inner surface of the battery cover by a pressure-sensitive adhesive.

[0052] In this implementation, the insulating aerogel material can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. Furthermore, when heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties, reducing or avoiding the appearance of local hot spots on the mainboard bracket and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0053] In a possible implementation manner of the second aspect, the heat insulating aerogel material is adhered to the contact position between the BTB bracket and the inner surface of the battery cover by a pressure-sensitive adhesive.

[0054] In this implementation, the insulating aerogel material can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties, reducing or avoiding the appearance of local hot spots on the BTB bracket and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0055] According to a third aspect, a method for preparing a thermal insulation material is provided, which comprises: dissolving a polymer powder in water, and adding at least a filler and a cross-linking agent and mixing them evenly to obtain a polymer aqueous solution; freezing and thawing the polymer aqueous solution multiple times to perform a cross-linking reaction to form a cross-linked hydrogel; providing a mold having a base and a mold cavity located on one side of the base; pouring the cross-linked hydrogel into the mold through an opening of the mold cavity, and successively subjecting the mixture to freeze casting and freeze drying to obtain a target thermal insulation material.

[0056] The embodiment of the present application provides a method for preparing a thermal insulation material, which obtains anisotropic thermal insulation aerogel material through steps such as directional freeze casting and freeze drying. The method is simple and easy to implement and is conducive to industrial production.

[0057] In a possible implementation of the third aspect, a method for preparing a thermal insulation material includes: dissolving a polymer powder in water, and adding at least a filler and a cross-linking agent and mixing them evenly to obtain a polymer aqueous solution; freezing and thawing the polymer aqueous solution multiple times to perform a cross-linking reaction to form a cross-linked hydrogel; providing a mold having a base and a mold cavity located on one side of the base; pouring the cross-linked hydrogel into the mold through an opening of the mold cavity, and successively performing freeze casting and freeze drying to obtain a first thermal insulation material; heating the first thermal insulation material at a high temperature to perform a thermal cross-linking reaction to obtain a target thermal insulation material.

[0058] In this implementation, the aerogel that has undergone cyclic freeze-thaw cross-linking is then subjected to a heat treatment to enhance the overall strength of the aerogel, making the target thermal insulation material stronger when compressed or heated, and reducing or avoiding problems such as cracking during compression or heating.

[0059] In a possible implementation of the third aspect, a method for preparing a thermal insulation material includes: dissolving a certain mass of PVA powder or PU powder or cellulose powder into deionized water, adding an inorganic filler and a cross-linking agent, and obtaining a polymer aqueous solution by mechanical stirring; freezing and thawing the polymer aqueous solution three times at a temperature of -24°C to 30°C to form a cross-linked hydrogel; pouring the cross-linked hydrogel into a plastic mold, immersing the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-drying for 48 hours; transferring the aerogel to an oven and heating it at 90°C for another hour, and after thermal cross-linking, obtaining an aerogel material with a certain mechanical strength.

[0060] In this implementation, anisotropic PVA / PU / cellulose thermal insulation aerogel material is obtained through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0061] In a possible implementation of the third aspect, the polymer powder includes a combination of one or more of water-soluble PVA powder, water-soluble PU powder, and water-soluble cellulose powder.

[0062] In this implementation, the polymer powder is simple and easy to obtain, and the formed aerogel material has good thermal insulation and compressibility.

[0063] In a possible implementation manner of the third aspect, the polymer powder is water-soluble PVA powder.

[0064] In this implementation, PVA powder is simple and easy to obtain, and the formed PVA aerogel material has good thermal insulation and compressibility.

[0065] In a possible implementation of the third aspect, the polymer aqueous solution is composed of a water-soluble resin (3% to 15% by mass), a filler (0.5% to 3% by mass), water (78% to 95% by mass), a cross-linking agent and a dispersant, a plasticizer, a thickener, a coupling agent, etc., or a combination of one or more of the above (0.5% to 10% by mass).

[0066] In this implementation, the formed aerogel material has good thermal insulation and compressibility.

[0067] In a possible implementation of the third aspect, the polymer aqueous solution is composed of a water-soluble resin (3% to 15% by mass), a filler (0.5% to 3% by mass), water (78% to 95% by mass), a cross-linking agent (0.5% to 10% by mass), and the like.

[0068] In this implementation, the formed aerogel material has good thermal insulation and compressibility.

[0069] In a possible implementation of the third aspect, the inorganic filler is selected from a combination of one or more of montmorillonite, hollow microbeads, carbon black, carbon nanotubes, graphene oxide, and the like.

[0070] In this implementation, montmorillonite, hollow microbeads, carbon black, carbon nanotubes, graphene oxide, etc. are simple and easy to obtain.

[0071] In a possible implementation of the third aspect, the number of freeze-thaw cycles is three times.

[0072] In this implementation, the aerogel material thus formed has good thermal insulation and compressibility, and also saves time and cost.

[0073] In a possible implementation of the third aspect, a first temperature is set for the polymer aqueous solution so that it is in a completely frozen state, and a second temperature is set for the polymer aqueous solution so that it is in a meltable state; wherein the first temperature range includes -50°C to -20°C, and the second temperature range includes 20°C to 40°C.

[0074] In this implementation, the formed thermal insulation material has good thermal insulation and compressibility.

[0075] In a possible implementation of the third aspect, the first temperature may be -24°C, and the second temperature may be 30°C, thereby setting the temperature range of the polymer aqueous solution cyclic freeze-thaw cycle to -24°C to 30°C.

[0076] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0077] In a possible implementation manner of the third aspect, the base is a copper plate, and the copper plate is immersed in liquid nitrogen, and the mold cavity is a plastic mold cavity.

[0078] In this implementation, liquid nitrogen can make the copper plate reach a temperature range of -24°C to 30°C, thereby causing the polymer aqueous solution to freeze and thaw cyclically.

[0079] In a possible implementation of the third aspect, the temperature range for high-temperature heating of the first thermal insulation material includes 70°C to 110°C.

[0080] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0081] In a possible implementation of the third aspect, the temperature at which the first thermal insulation material is heated is 90°C.

[0082] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0083] In a possible implementation of the third aspect, the time range for high-temperature heating of the first thermal insulation material includes 0.5h~2h.

[0084] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0085] In a possible implementation of the third aspect, the first thermal insulation material is heated at high temperature for 1 hour.

[0086] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0087] In a possible implementation of the third aspect, the freeze-drying method is freeze-drying under vacuum for 48 hours.

[0088] In this implementation, the thermal insulation material can have better thermal insulation and compressibility.

[0089] In a possible implementation of the third aspect, the mass range of the polymer powder relative to the mass of water includes 5% to 15%.

[0090] In this implementation, by controlling the solute content to control the freezing rate of the polymer aqueous solution, the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns in the formed insulating aerogel material can be controlled to be approximately 60°, thereby making the insulating effect of the insulating aerogel material better.

[0091] In a possible implementation manner of the third aspect, the metal plate is placed in liquid nitrogen, and the temperature range of the metal plate is set to include -90°C~20°C.

[0092] In this implementation, by controlling the solute content and / or setting the temperature of the metal plate to control the freezing rate of the polymer aqueous solution, the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns in the formed insulating aerogel material can be controlled to be approximately about 60°, thereby making the insulating effect of the insulating aerogel material better.

[0093] In a possible implementation of the third aspect, the mass range of the polymer powder relative to the mass of water includes 5%~15%, and the metal plate is placed in liquid nitrogen, and the temperature range of the metal plate is set to include -90°C~20°C.

[0094] In this implementation, by controlling the solute content and setting the temperature of the metal plate to control the freezing rate of the polymer aqueous solution, the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns in the formed insulating aerogel material can be controlled to be approximately about 60°, thereby making the insulating effect of the insulating aerogel material better.

[0095] In a possible implementation of the third aspect, a method for preparing a thermal insulation material includes: dissolving a certain mass of PVA powder into deionized water, adding an inorganic filler and a cross-linking agent, and obtaining a PVA aqueous solution by mechanical stirring; freezing and thawing the PVA aqueous solution three times at temperatures of -24°C and 30°C to form a cross-linked PVA hydrogel; pouring the cross-linked PVA hydrogel into a plastic mold, immersing the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-drying for 48 hours to form an aerogel; transferring the aerogel to an oven and heating it at 90°C for another hour, and after thermal cross-linking, obtaining a PVA thermal insulation aerogel material with a certain mechanical strength.

[0096] In this implementation, anisotropic PVA thermal insulation aerogel material is obtained through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0097] In a possible implementation of the third aspect, a method for preparing a thermal insulation material includes: dissolving a certain mass of PU powder into deionized water, adding an inorganic filler and a cross-linking agent, and obtaining a PU aqueous solution by mechanical stirring; freezing and thawing the PU aqueous solution three times at temperatures of -24°C and 30°C to form a cross-linked PU hydrogel; pouring the cross-linked PU hydrogel into a plastic mold, immersing the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-drying for 48 hours to form an aerogel; transferring the aerogel to an oven and heating it at 90°C for another hour, and after thermal cross-linking, obtaining a PU thermal insulation aerogel material with a certain mechanical strength.

[0098] In this implementation, anisotropic PU thermal insulation aerogel material is obtained through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0099] In a possible implementation of the third aspect, a method for preparing a thermal insulation material includes: dissolving a certain mass of cellulose powder into deionized water, adding an inorganic filler and a cross-linking agent, and obtaining a cellulose aqueous solution by mechanical stirring; freezing and thawing the cellulose aqueous solution three times at temperatures of -24°C and 30°C to form a cross-linked cellulose hydrogel; pouring the cross-linked cellulose hydrogel into a plastic mold, immersing the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-drying for 48 hours to form an aerogel; transferring the aerogel to an oven and heating it at 90°C for another hour, and after thermal cross-linking, obtaining a cellulose thermal insulation aerogel material with a certain mechanical strength.

[0100] In this implementation, anisotropic cellulose thermal insulation aerogel material is obtained through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0101] The embodiment of the present application provides a thermal insulation material, which is an anisotropic aerogel material, and its microstructure is similar to the microstructure of penguin feathers, so it has a thermal insulation effect similar to penguin feathers, can withstand high temperatures, maintain constant temperature, and is light in weight and high in strength, thereby providing good thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties. At the same time, the thermal insulation aerogel material has excellent compressibility. Therefore, when the aerogel material is used in electronic equipment, it can be compressed and can also play a good role in local thermal insulation and heat protection. In addition, the preparation method of the thermal insulation material is simple and easy to implement, which is conducive to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 A schematic diagram of the overall structure of an electronic device provided in an embodiment of the present application;

[0103] Figure 2 for Figure 1 A schematic diagram of a disassembled structure of an electronic device;

[0104] Figure 3 A schematic diagram of the structure of a heat-insulating foam material in a related technology provided in an embodiment of the present application;

[0105] Figure 4 A schematic diagram of the structure of a heat-insulating foam material in a related technology provided in an embodiment of the present application;

[0106] Figure 5 A schematic diagram of the temperature distribution on the back of a mobile phone when it is running provided in an embodiment of the present application;

[0107] Figure 6 A schematic diagram of temperature distribution on the back of another mobile phone during operation provided by an embodiment of the present application;

[0108] Figure 7 A process flow chart of a thermal insulation material provided in an embodiment of the present application;

[0109] Figure 8 A process flow chart of another thermal insulation material provided in an embodiment of the present application;

[0110] Fig. 9 A process flow chart of another thermal insulation material preparation method provided in the embodiment of the present application;

[0111] Fig.10 A process flow chart of another thermal insulation material preparation method provided in the present application;

[0112] Fig.11 An electron microscope image of the first thermal insulation material provided in the embodiment of the present application;

[0113] Fig.12 An electron microscope image of the second thermal insulation material provided in the embodiment of the present application;

[0114] Fig.13 An electron microscope image of the third thermal insulation material provided in the embodiment of the present application;

[0115] Fig.14 An electron microscope image of the fourth thermal insulation material provided in the embodiment of the present application;

[0116] Fig.15 An electron microscope image of the fifth thermal insulation material provided in the embodiment of the present application;

[0117] Fig.16An electron microscope image of the sixth thermal insulation material provided in the embodiment of the present application;

[0118] Fig.17 A schematic diagram of the result of repeated compression of an aerogel material provided in an embodiment of the present application;

[0119] Fig.18 A heat distribution diagram of an aerogel material provided in an embodiment of the present application when placed under 1 sun intensity in an xz plane;

[0120] Fig.19 A heat distribution diagram in the xz plane of a conventional aerogel material provided in a related art provided in an embodiment of the present application when placed under irradiation with 1 sun intensity;

[0121] Fig. 20 A heat distribution diagram in the y direction of an aerogel material provided in an embodiment of the present application when placed under irradiation with 1 sun intensity;

[0122] Fig.21 A heat distribution diagram in the y direction of a conventional aerogel material provided in a related art provided in an embodiment of the present application when placed under irradiation with a sunlight intensity of 1;

[0123] Fig. 22 A schematic diagram of a partial structure of an electronic device provided in an embodiment of the present application;

[0124] Fig.23 A partial structural diagram of another electronic device is provided for an embodiment of the present application;

[0125] Fig.24 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0126] Fig.25 A schematic diagram of the structure of another electronic device provided in an embodiment of the present application;

[0127] Fig.26 A schematic diagram of the structure of another electronic device provided in an embodiment of the present application;

[0128] Fig. 27 for Fig. 9 A flow chart of the actual process of forming aerogel materials;

[0129] Fig.28 for Fig.10 The actual process flow chart of forming PVA thermal insulation aerogel material.

[0130] Reference numerals:

[0131] 01-Mobile phone;

[0132] 100-display screen;

[0133] 101-middle frame;

[0134] 102- rear shell;

[0135] 103-circuit board assembly;

[0136] 1031-main circuit board;

[0137] 1032-Electronic components;

[0138] 104-battery;

[0139] 02-Thermal insulation aerogel material;

[0140] 03-Electronic equipment. DETAILED DESCRIPTION

[0141] The technical solutions in the embodiments of the present application will be described clearly and in detail below in conjunction with the accompanying drawings.

[0142] In the description of the embodiments of the present application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B, which can be expressed as: A exists alone, B exists alone, and A and B exist at the same time.

[0143] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0144] In the description of the embodiments of the present application, unless otherwise specified, “at least one” means one or more than one; and “plurality” means two or more than two.

[0145] Some of the terms used in the embodiments of the present application are explained below so that those skilled in the art can better understand them.

[0146] 1. Aerogel

[0147] Aerogel refers to a solid porous material with air as the medium to fill most of its internal space. Aerogel uses gas to replace the liquid in the gel, but it does not essentially change the gel network structure or volume. It is the product of hydrogel or organic gel drying, and has the characteristics of high porosity, large specific surface area, low density, good sound insulation, good heat insulation, and unique three-dimensional network structure.

[0148] 2. Polyvinyl alcohol (PVA)

[0149] PVA is a non-toxic, non-corrosive, biodegradable, water-soluble organic polymer.

[0150] 3. Polyurethane (PU)

[0151] PU is the full name of polyurethane, which is a high molecular compound. PU has two major categories: polyester type and polyether type. It can be made into polyurethane plastics (mainly foam plastics), polyurethane fibers (called spandex in China), polyurethane rubber and elastomers.

[0152] 4. Cellulose

[0153] Cellulose is a macromolecular polysaccharide composed of glucose. It is the most widely distributed and abundant polysaccharide in nature.

[0154] 5. Plain leather battery cover

[0155] A plain leather battery cover refers to a battery cover with a layer of leather pasted on a fiberglass board or substrate.

[0156] 6. Freeze and Thaw

[0157] Freeze-thaw refers to the process of freezing and melting of substances due to the temperature dropping below zero and rising above zero.

[0158] 7. BTB bracket

[0159] The BTB bracket refers to a connector used to connect two electronic components. The connector has a simple structure, is easy to install, and can be reused. It is widely used in electronic equipment connection and wiring connection.

[0160] 8. Anisotropy

[0161] Anisotropy means that all or part of the chemical, physical and other properties of a substance change with the change of direction, showing different properties in different directions.

[0162] 9. Thermal conductivity

[0163] Thermal conductivity refers to the temperature difference of the two sides of the sample when the material is made into a sample under stable heat transfer conditions. The temperature difference is 1℃ and the temperature of the sample passes through 1m within 1s. 2 Heat transferred by area.

[0164] The unit of thermal conductivity is Watt / (meter•degree), that is, W / (m•K), which is related to factors such as the composition structure, density, moisture content, and temperature of the material.

[0165] 10. Compressive strength

[0166] Compression strength refers to the maximum compressive stress that a sample can withstand after the material is made into a sample during a compression test.

[0167] The above is a brief introduction to the nouns involved in the embodiments of the present application, which will not be repeated below.

[0168] The application scenarios of the embodiments of the present application, the thermal insulation materials provided in the related technologies, etc. are introduced below to facilitate a clearer understanding of the embodiments of the present application.

[0169] The embodiment of the present application provides an electronic device, and no limitation is imposed on the specific type of the electronic device. In some embodiments, the electronic device provided by the present application may include consumer electronic terminal products, household electronic products, vehicle-mounted electronic products, financial terminal electronic products, and communication electronic products.

[0170] Among them, consumer electronic terminal products may include mobile phones, tablet computers, laptops, notebook computers, handheld computers, personal computers (PCs), e-readers, desktop monitors, cellular phones, drones, personal digital assistants (PDAs), smart wearable devices (e.g., smart bracelets, smart watches, headphones, etc.), ultra-mobile personal computers (UMPCs), augmented reality (AR) / virtual reality (VR) devices and other Internet of Things (IOT) devices.

[0171] Home electronic products may include televisions, smart door locks, remote controls, refrigerators, rechargeable small household appliances (e.g., soymilk makers, sweeping robots, etc.), printers, projectors, etc.

[0172] The vehicle-mounted electronic products may include a vehicle-mounted navigation system, a vehicle-mounted high-density digital video disc (DVD), and the like.

[0173] Financial terminal electronic products may include automated teller machines (ATMs), self-service terminals, etc.

[0174] Communication electronic products may include communication equipment such as servers, storage devices, and base stations.

[0175] The embodiments of the present application do not limit the specific form of the electronic device. For the convenience of description, the following embodiments are all illustrated by taking the electronic device as a mobile phone.

[0176] Please refer to Figure 1 and Figure 2 , Figure 1 is an overall schematic diagram of an electronic device applicable to some embodiments of the present application, Figure 2 for Figure 1 Schematic diagram of the disassembled electronic device shown.

[0177] in, Figure 1 and Figure 2 The electronic devices shown are all described by taking a tablet phone as an example. In other embodiments, the electronic device may also be other types of mobile phones, such as a foldable mobile phone.

[0178] exist Figure 1 and Figure 2 In the example of FIG. 1 , the electronic device may include a display screen 100, a middle frame 101, a rear housing 102, a circuit board assembly 103, and a battery 104. It is understood that Figure 1 and Figure 2 The following figures and the related drawings only schematically illustrate some components of the electronic device, and the actual shape, size, position and structure of these components are not subject to Figure 1 and Figure 2 and the limitations of the accompanying drawings below.

[0179] The specific structure of the electronic device to which the embodiments of the present application are applicable is further described below.

[0180] Please refer to Figure 1 and Figure 2 Taking the electronic device as a mobile phone 01 as an example, the mobile phone 01 may include a display screen 100 and a middle frame 101 , and the display screen 100 is located on one side of the middle frame 101 .

[0181] In applications, the display screen 100 can be used to display images, videos, etc.

[0182] It should be noted that the display screen 100 can be any one of a liquid crystal display (LCD), an organic light emitting diode (OLED) display screen, a sub-millimeter light emitting diode (Mini LED) display screen, a micro light emitting diode (Micro LED) display screen, etc.

[0183] exist Figure 1In the embodiment shown, the shape of the electronic device can be a rectangular flat plate. Of course, the shape of the electronic device can also be any other shape, which depends on the actual application.

[0184] like Figure 2 As shown, the mobile phone 01 may also include structures such as a rear shell 102 , a circuit board assembly 103 and a battery 104 .

[0185] Among them, the rear shell 102 can be set on the side of the middle frame 101 away from the display screen 100; and the rear shell 102 and the middle frame 101 can enclose an internal storage space of the mobile phone 01, and the internal storage space can accommodate structures such as the circuit board assembly 103 and the battery 104.

[0186] The circuit board assembly 103 may include a main circuit board 1031 and electronic components 1032 , etc. The main circuit board 1031 may be used to carry the electronic components 1032 and perform signal interaction with the electronic components 1032 . Figure 2 The circuit board assembly 103 includes two electronic components 1032. Of course, the number of the electronic components 1032 is not limited to two, which depends on the actual application.

[0187] In applications, the main circuit board 1031 may include printed circuit boards (PCB), FPC, etc.

[0188] The electronic components 1032 may include, but are not limited to, chips, resistors, capacitors, inductors, potentiometers, electron tubes, heat sinks, electromechanical components, connectors, discrete semiconductors, sensors, power supplies, switches, micro motors, electronic transformers, relays, subscriber identity module (SIM) card holders, etc.

[0189] Please refer to Figure 2 The battery 104 can be used to provide power to structures in the mobile phone 01 such as the display screen 100 and the circuit board assembly 103.

[0190] In some embodiments, the surface of the middle frame 101 facing the rear housing 102 may be provided with a battery installation slot ( Figure 2 (not shown in the figure), the battery 104 can be installed in the battery installation slot.

[0191] In addition, a battery cover ( Figure 2 (not shown) to protect the battery 104, the specific details will be determined according to actual application.

[0192] Of course, the mobile phone 01 may also include other structures such as a microphone, a speaker, a camera assembly, etc. Here, only the contents related to the invention point are introduced, and the rest are not described in detail.

[0193] The following is a detailed description of the thermal insulation solution provided in the related art.

[0194] At present, local hot spots may occur at the contact positions between some structures in mobile phones and the battery cover, such as the contact position between the local protrusion of the battery FPC and the battery cover, the contact position between the motherboard bracket and the battery cover, and the contact position between the BTB bracket and the battery cover, which seriously affects its charging speed and thermal experience.

[0195] In order to solve the above problems, heat insulating materials are often added at the contact positions between these structures and the battery cover to reduce or avoid the occurrence of local hot spots.

[0196] Two major categories of thermal insulation materials commonly used in the relevant technology are given below.

[0197] As an example, Figure 3 The random structure of the insulation foam material is shown; Figure 4 The insulating foam material is illustrated.

[0198] In the related art, the insulating foam materials used at the local hot spots of mobile phones include rigid polymer or cellulose-based foam materials, such as expanded or extruded polystyrene (EPS), polyisocyanurate, wood chips, glass fibers, cork, etc. The high porosity of these materials can reduce air conduction and convection to provide suitable insulation.

[0199] However, since the closed pores of the above-mentioned thermal insulation foam materials or thermal insulation foam materials are isotropic, the solid heat conduction through the pore wall is quite high, making the thermal conductivity of these materials relatively high and the thermal insulation effect under compression poor; among them, the thermal conductivity of the material can be as high as 0.2W / (m•K), causing the battery cover where the material contacts to become a local hot spot, affecting the charging speed. In addition, the mechanical reliability test performance of these materials is also poor. For example, some materials are prone to slag during compression, and some materials have high resilience.

[0200] Figure 5 and Figure 6 The temperature distribution diagrams of different positions on the back of the mobile phone are shown respectively when the mobile phone is running. Figure 5 It shows the temperature diagram of adding compressed foam between the motherboard bracket and the battery cover; Figure 6 It illustrates the deformation of the plain leather battery cover under the extremely thin structure, and the local hot spot phenomenon caused by the contact between the BTB bracket and the battery cover.

[0201] like Figure 5As shown, the temperatures of local areas on the back of the mobile phone are 40.5786℃, 40.599℃, 40.0709℃, 40.1932℃ and 40.3933℃. The temperatures are relatively high and the thermal effect is poor, causing the battery cover in contact with the foam to become a local hot spot.

[0202] like Figure 6 As shown, the temperatures of some areas on the back of the phone are 40.9431°C and 40.9393°C. The temperatures are relatively high and the thermal effect is poor, causing the battery cover in contact with the foam to become a local hot spot.

[0203] As another example, ceramic aerogel materials made from ceramic nanosheets, nanofibers, and nanoparticles have become an emerging thermal insulation material due to their advantages such as low density, ultra-low thermal conductivity, high temperature resistance, and fire resistance. Some mobile phones use ceramic aerogels for thermal insulation in local overheating areas.

[0204] However, ceramic aerogels have poor mechanical properties, and most of them easily fall off during compression, which severely limits their practical applications due to their relatively poor mechanical properties.

[0205] Then, based on the above two examples, it can be seen that the thermal insulation materials provided by the relevant technologies cannot achieve good thermal insulation effects and mechanical properties.

[0206] In view of this, an embodiment of the present application provides an insulating material based on a bionic penguin feather arrangement, wherein the insulating material is an anisotropic aerogel material, and the microstructure of the aerogel material is similar to the microstructure of penguin feathers, and thus has a similar insulating effect as penguin feathers, can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties, and at the same time, the aerogel material has excellent compressibility.

[0207] When the thermal insulation material provided in the embodiment of the present application is applied to an electronic device, the thermal insulation material can be adhered to the inner side of the battery cover of the electronic device by means of a pressure-sensitive adhesive, so that the electronic device has better local thermal insulation, thereby improving the overall performance of the electronic device.

[0208] The embodiment of the present application provides a method for preparing a thermal insulation material. The preparation method sequentially obtains anisotropic thermal insulation aerogel material through steps such as directional freeze casting and freeze drying. The method is simple and easy to implement and is conducive to industrial production.

[0209] Combine the following Figures 7 to 28 , the thermal insulation material and the preparation method thereof provided in the embodiments of the present application are introduced in detail.

[0210] Now combined Figures 7 to 10 , Fig.28, the preparation method of the thermal insulation material provided in the embodiment of the present application is specifically introduced.

[0211] like Figure 7 As shown, the preparation method of the thermal insulation material provided in the embodiment of the present application includes:

[0212] S1. Dissolving polymer powder in water, and adding at least a filler and a cross-linking agent and mixing them evenly to obtain a polymer aqueous solution.

[0213] In applications, the polymer powder may include one or more combinations of water-soluble PVA powder, water-soluble PU powder, and water-soluble cellulose powder.

[0214] Furthermore, the polymer powder may be water-soluble PVA powder.

[0215] In applications, the above-mentioned polymer aqueous solution is composed of a water-soluble resin (3% to 15% by mass), a filler (0.5% to 3% by mass), water (78% to 95% by mass), a cross-linking agent and other additives (0.5% to 10% by mass).

[0216] Specifically, the water-soluble resin is a water-soluble polymer resin.

[0217] It should be noted that other additives may not be added in step S1, and the mass percentage of the cross-linking agent may be 0.5% to 10%; or other additives may be added in step S1, and the mass percentage of the cross-linking agent and other additives may be 0.5% to 10%.

[0218] It should be understood that the purpose of adding a cross-linking agent is to increase the overall density and strength of the thermal insulation material.

[0219] In the case of adding other auxiliary agents in step S1, the other auxiliary agents may include one or a combination of two or more of a dispersant, a plasticizer, a thickener, a coupling agent, etc.

[0220] In applications, the inorganic filler may be selected from one or more combinations of montmorillonite, hollow microbeads, carbon black, carbon nanotubes, graphene oxide, and the like.

[0221] It should be understood that the purpose of adding inorganic fillers is to improve the overall strength of the thermal insulation material.

[0222] Furthermore, the filler may be a nanofiller or the like.

[0223] In application, the water used in the above step S1 can be deionized water, plasma water, etc.

[0224] S2. freeze-thaw the polymer aqueous solution for multiple times to perform a cross-linking reaction and form a cross-linked hydrogel.

[0225] In applications, the number of freeze-thaw cycles may be 2, 3, 4, 5, 6 or 7 times, etc., depending on the performance that the thermal insulation material needs to achieve.

[0226] In applications, the polymer aqueous solution may be set to a first temperature so that it is in a completely frozen state, and the polymer aqueous solution may be set to a second temperature so that it is in a thawable state.

[0227] The first temperature range may include -50°C to -20°C, and the second temperature range may include 20°C to 40°C. For example, the first temperature may be -50°C, -45°C, -40°C, -30°C, -24°C or -20°C, and the second temperature may be 20°C, 25°C, 30°C, 35°C, 38°C or 40°C.

[0228] Furthermore, the first temperature may be -24°C, and the second temperature may be 30°C. Thus, the temperature range of the polymer aqueous solution freeze-thaw cycle may be set at -24°C to 30°C, at which time the subsequently formed thermal insulation material may have better thermal insulation and compressibility.

[0229] It should be noted that, during the above process, the polymer powder becomes sticky. During the process of becoming sticky, the filler and the cross-linking agent can be fully mixed and wrapped inside the polymer powder to form cross-linking sites during subsequent casting and heating.

[0230] S3. Provide a mold comprising a base and a mold cavity located on one side of the base.

[0231] One end of the mold cavity is fixed to the base, and the other end is open.

[0232] In application, there is no specific limitation on the material and size of the base, which can be determined according to the required heat insulation material. For example, the base can be made of metal, such as copper (Cu).

[0233] In application, the material and size of the mold cavity are not specifically limited and can be determined according to the heat insulation material to be formed. For example, the material of the mold cavity can be plastic or the like.

[0234] Thus, the mold may include a metal plate and a plastic mold cavity sleeved on the metal plate, wherein the plastic mold cavity has an opening on a side away from the metal plate, and the metal plate may be immersed in liquid nitrogen to freeze the metal plate.

[0235] S4. Pour the cross-linked hydrogel into the mold through the opening of the mold cavity, and obtain the target thermal insulation material after freeze casting and freeze drying in sequence.

[0236] It should be understood that the embodiment of the present application can pour the cross-linked hydrogel into the mold through the opening of the mold cavity. Since the metal transfer speed is faster than the air transfer speed, rapid cooling can be achieved along the direction of the metal plate transfer, which is equivalent to freeze-drying water.

[0237] Therefore, when the polymer aqueous solution is poured into the mold, the polymer aqueous solution freezes quickly. First, the polymer aqueous solution in contact with the metal plate forms an ice crystal base, and the ice crystal base is densely and continuously distributed in the first plane; then, along the direction perpendicular to the first plane, the ice crystals connected to the ice crystals in the first plane grow upward, and at least one ice crystal column and a plurality of ice crystal branches arranged along the ice crystal column are grown. Adjacent ice crystal branches are separated and arranged at intervals, and there is an angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal column.

[0238] Thus, a thermal insulation aerogel material is formed whose microstructure is similar to that of penguin feathers. The thermal insulation aerogel material has anisotropy, and the thermal efficiency of the structure itself is higher than that of conventional materials, and has excellent compressibility.

[0239] It should be noted that the order of the above steps S1~S2 and step S3 is not limited. Steps S1~S2 can be performed first, and then step S3; or, step S3 can be performed first, and then step S1~S2; or, steps S1~S2 and step S3 can be performed at the same time, which shall be subject to actual application.

[0240] The embodiment of the present application provides a method for preparing a thermal insulation material, which obtains anisotropic thermal insulation aerogel material through steps such as directional freeze casting and freeze drying. The method is simple and easy to implement and is conducive to industrial production.

[0241] Alternatively, as an implementable approach, such as Figure 8 As shown, the above step S4, pouring the cross-linked hydrogel into the mold through the opening of the mold cavity, and sequentially performing freeze casting and freeze drying to obtain the target thermal insulation material includes:

[0242] S41, pouring the cross-linked hydrogel into the mold through the opening of the mold cavity, and sequentially performing freeze casting and freeze drying to obtain a first thermal insulation material.

[0243] S42, heating the first thermal insulation material at a high temperature to perform a thermal cross-linking reaction to obtain a target thermal insulation material.

[0244] Wherein, the mechanical strength of the target thermal insulation material is greater than the mechanical strength of the first thermal insulation material.

[0245] In applications, the temperature range for high-temperature heating of the first thermal insulation material may include 70°C~110°C, and there is no specific limitation on the temperature. For example, the temperature may be 70°C, 75°C, 80°C, 90°C, 100°C or 110°C, etc.

[0246] Furthermore, the above temperature can be selected as 90°C.

[0247] In applications, the time range for high-temperature heating of the first thermal insulation material may include 0.5h~2h, and there is no specific limitation on the time. Exemplarily, the time may be 0.5h, 0.8h, 1h, 1.5h or 2h.

[0248] Furthermore, the above time can be selected as 1 hour.

[0249] In application, there is no specific limitation on the instrument for heating the first thermal insulation material at high temperature. For example, the first thermal insulation material can be placed in an oven for high temperature heating.

[0250] In the application, there is no specific limitation on the freeze-drying method, time, etc., and illustratively, freeze-drying can be performed under vacuum for 48 hours.

[0251] The method for preparing the thermal insulation material provided in the embodiment of the present application further heats the aerogel that has undergone cyclic freeze-thaw cross-linking to enhance the overall strength of the aerogel, thereby making the target thermal insulation material stronger when compressed or heated, and reducing or avoiding problems such as cracking during compression or heating.

[0252] Optionally, as an achievable manner, relative to the mass of water in step S1, the mass range of the polymer powder includes 5% to 15%.

[0253] And / or, placing the metal plate in liquid nitrogen, and setting the temperature of the metal plate to a range of -90°C to 20°C.

[0254] In application, the mass of the polymer powder relative to the mass of water in step S1 is not specifically limited. For example, the mass of the polymer powder relative to the mass of water in step S1 may be 5%, 6%, 10%, 12%, 13% or 15%, etc.

[0255] In application, there is no specific limitation on the temperature at which the metal plate is placed in liquid nitrogen. For example, the temperature at which the metal plate is placed in liquid nitrogen may be -90°C, -60°C, -30°C, -10°C, 0°C or 20°C.

[0256] The method for preparing the thermal insulation material provided in the embodiment of the present application controls the freezing rate of the polymer aqueous solution by controlling the solute content and / or setting the temperature of the metal plate, so that the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns in the formed thermal insulation aerogel material can be controlled to be approximately about 60°, thereby making the thermal insulation effect of the thermal insulation aerogel material better.

[0257] Please combine the following Fig. 9 and Fig. 27 , the preparation method of the thermal insulation material provided in the embodiments of the present application is introduced in more detail.

[0258] like Fig. 9 As shown, the method for preparing the thermal insulation material provided in the embodiment of the present application comprises the following steps:

[0259] S01. Dissolve a certain mass of polymer powder in deionized water, add inorganic filler and cross-linking agent, and obtain polymer aqueous solution by mechanical stirring.

[0260] S02. Freeze-thaw the polymer aqueous solution three times at a temperature of -24°C to 30°C to form a cross-linked hydrogel.

[0261] S03. Pour the cross-linked hydrogel into a plastic mold, immerse the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-dry for 48 h.

[0262] S04. The aerogel was transferred to an oven and heated at 90°C for another 1 h. After thermal crosslinking, an aerogel material with a certain mechanical strength was obtained.

[0263] It should be noted that Fig. 27 yes Fig. 9 Figure 1 is a flow chart of the actual process of forming aerogel material.

[0264] The preparation method of the thermal insulation material provided in the embodiment of the present application obtains anisotropic PVA / PU / cellulose thermal insulation aerogel material through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0265] Please combine the following Fig.10 and Fig.28 , taking the polymer powder as PVA powder as an example, the preparation method of the thermal insulation material provided in the embodiment of the present application is specifically introduced.

[0266] like Fig.10 As shown, the method for preparing the thermal insulation material provided in the embodiment of the present application comprises the following steps:

[0267] S11. Dissolve a certain mass of PVA powder in deionized water, add inorganic fillers and cross-linking agents, and obtain a PVA aqueous solution by mechanical stirring.

[0268] S12. The PVA aqueous solution was freeze-thawed three times at -24°C and 30°C to form a cross-linked PVA hydrogel.

[0269] S13. Pour the cross-linked PVA hydrogel into a plastic mold, immerse the copper end in liquid nitrogen for directional freeze casting, and then vacuum freeze-dry for 48 h to form an aerogel.

[0270] It should be noted that when the temperature is frozen, the water and polymer in the PVA aqueous solution undergo phase separation, the water in the solution forms ice crystals, and the PVA forms a three-dimensional network structure.

[0271] S14. The aerogel is transferred to an oven and heated at 90°C for another 1 h. After thermal crosslinking, a PVA thermal insulation aerogel material with a certain mechanical strength is obtained.

[0272] It should be noted that Fig.28 yes Fig.10 The actual process flow chart of forming PVA thermal insulation aerogel material.

[0273] The method for preparing the thermal insulation material provided in the embodiment of the present application obtains anisotropic PVA thermal insulation aerogel material through the steps of directional freeze casting, freeze drying, thermal cross-linking, etc., which is simple and easy to implement and is conducive to industrial production.

[0274] Combine the following Figures 11 to 21 , the thermal insulation material provided in the embodiments of the present application is specifically introduced.

[0275] Most penguins live in the extremely cold Antarctic. Penguins are naturally warm-blooded animals, and they can use their thin feathers to achieve excellent insulation and moisture resistance, thereby resisting the extremely cold environment. However, on average, penguin feathers only account for 3% to 4% of their total weight.

[0276] The study believes that the feather structure of penguins may be the reason for the heat insulation and moisture resistance required in extremely cold conditions. The key lies in the fact that these feathers are arranged closely and orderly with a certain geometric pattern, which can provide protection in terms of heat insulation and moisture resistance. At the same time, there are certain gaps between the arrangement of these feathers, which can achieve a constant temperature effect, thereby playing an important role in resisting the cold.

[0277] Inspired by the thermal management strategies of penguins, e.g. Figures 11 to 16As shown, the thermal insulation material provided by the embodiment of the present application includes: an ice crystal base, which is actually a three-dimensional structure, and the ice crystals in the ice crystal base are densely and continuously distributed at least along the xz plane; and an ice crystal unit, which includes at least one ice crystal column, and the ice crystal column extends along the freezing direction / ice crystal growth direction (y direction), and the ice crystals in the ice crystal column that are in contact with the ice crystal base are connected to the ice crystals in the ice crystal base, and the ice crystal column has a plurality of ice crystal branches (also called ligaments), and adjacent ice crystal branches are separated and arranged at intervals, and the extension direction of the ice crystal branches is different from the extension direction of the ice crystal column.

[0278] It should be understood that in the embodiment of the present application, a polymer aqueous solution, for example, an aqueous solution containing water-soluble PVA, a dispersant and an inorganic filler is poured into the mold along the opening of the mold cavity. The material derived from ice growth is gradually frozen from the xz plane close to the copper plate to the y direction away from the copper plate, that is, the ice crystal base is first grown, and then from the xz plane, ice crystal columns and ice crystal branches are continuously grown upward along the y direction. In this way, the thermal insulation aerogel material in the embodiment of the present application is formed, and the thermal insulation aerogel material has anisotropy and compressibility, and its thermal insulation effect is better than that of traditional thermal insulation materials.

[0279] It should be understood that anisotropy means that the thermal insulation aerogel material exhibits different microstructures and macroscopic properties along the ice crystal growth direction (y direction) and perpendicular to the ice crystal growth direction (z direction).

[0280] Compressibility means that the thermal insulation aerogel material itself can be compressed. The microstructure of the penguin feather increases the repeated compressibility and structural consistency of the thermal insulation aerogel material.

[0281] It should be noted that the thermal insulation aerogel material used in electronic devices is in a solid state.

[0282] Figures 11 to 16 The microscopic morphology of the thermal insulation aerogel material 02 is shown schematically. Fig.11 This is an enlarged view of the overall microstructure of the thermal insulation aerogel material 02.

[0283] It should be noted that Fig.11 The insulating aerogel material 02 in the experiment is an anisotropic feather-like network structure, which contains longitudinal ice crystal columns arranged along the freezing direction. There is an angle between the parallel ligaments and the ice crystal columns, which produces a unique 3D structure.

[0284] Fig.12 This is an enlarged view of the ice crystal base microstructure of the thermal insulation aerogel material 02 in the xz plane.

[0285] Fig.13 This is an enlarged view of the microstructure of the thermal insulation aerogel material 02 in the yz plane.

[0286] It should be noted that Fig.13 The thermal insulation aerogel material 02 includes porous oriented channels with a width of about 50 µm. The porous oriented channels are horizontally arranged along the growth direction of ice crystals and sandwiched between adjacent ice crystal columns.

[0287] Fig.14 This is an enlarged view of the microstructure of the thermal insulation aerogel material 02 in the yz plane.

[0288] It should be noted that Fig.14 The thermal insulation aerogel material 02 in the present invention comprises longitudinal ice crystal columns arranged along the freezing direction, and the parallel ligaments are at an angle of about 60° to the ice crystal columns. Fig.11 The feather-like network structure shown produces a unique 3D structure.

[0289] It should be understood that the extension direction of the ice crystal branches is different from the extension direction of the ice crystal columns, including: an angle is formed between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns.

[0290] There is no specific limitation on the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns. For example, the angle between the extension direction of the ice crystal branches and the extension direction of the ice crystal columns can be an acute angle.

[0291] The embodiment of the present application provides a thermal insulation material, which is an anisotropic aerogel material. The microstructure of the aerogel material is similar to the microstructure of penguin feathers, and thus has a thermal insulation effect similar to that of penguin feathers. It can withstand high temperatures and maintain a constant temperature, and is light in weight and high in strength, thereby providing excellent thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties. At the same time, the thermal insulation aerogel material has excellent compressibility.

[0292] Therefore, when the aerogel material is used in electronic equipment, it can not only be compressed but also play a good role in local heat insulation and heat protection.

[0293] Alternatively, as an implementable approach, such as Figures 11 to 16 As shown, the ice crystal unit includes a plurality of ice crystal columns, and there are orientation channels between adjacent ice crystal columns, the orientation channels are arranged along the y direction, sandwiched between adjacent ice crystal columns, and ice crystal branches are distributed in the orientation channels. Thus, the aerogel material can have better thermal insulation and compressibility.

[0294] In applications, the width of the above-mentioned orientation channel parallel to the xz plane may range from 40µm to 60µm. There is no specific limitation on the width of the orientation channel parallel to the xz plane, and the width of the orientation channel parallel to the xz plane may be 40µm, 43µm, 48µm, 50µm, 55µm or 60µm, etc.

[0295] In applications, each orientation channel has a plurality of discrete and spaced holes, forming abundant ligaments in the porous orientation channel.

[0296] Furthermore, the abundant ligaments can divide the porous oriented channel into microchannels with a width ranging from 10µm to 20µm in the z direction at an angle of about 60°. There is no specific limitation on the width of the microchannel. For example, the width of the microchannel can be 10µm, 12µm, 14µm, 16µm, 18µm or 20µm, etc.

[0297] Alternatively, as an implementable approach, such as Figures 11 to 16 As shown, the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column is an acute angle, thereby making the aerogel material have a better thermal insulation effect.

[0298] Furthermore, the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column can be set to range from 50° to 80°, thereby making the heat insulation effect of the aerogel material better.

[0299] There is no specific limitation on the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column. For example, the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column can be 50°, 55°, 60°, 65°, 70° or 80°, etc.

[0300] Furthermore, the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column is about 60°, at which time the thermal insulation of the aerogel material is the best.

[0301] Alternatively, as an implementable approach, such as Figures 11 to 16 As shown, each ligament has a plurality of discrete and spaced pores inside. Thus, the thermal insulation of the aerogel material can be improved through the pores inside the ligament.

[0302] There is no specific limitation on the distribution and shape of the pores on each ice crystal dendrite, which can be obtained according to the actual preparation process.

[0303] As an example, each ligament has small pores with a size of less than 1µm inside. The small pores inside the ligament can improve the thermal insulation and compressibility of the aerogel material.

[0304] Furthermore, the shape of the orthographic projection of the pores on the ice crystal branches on the xz plane can be set to be a circle, and in this case, the diameter of the circle is less than 1 µm.

[0305] There is no specific limitation on the diameter of the circle. For example, the diameter of the circle may be 0.1µm, 0.2µm, 0.3µm, 0.4µm, 0.5µm or 0.6µm.

[0306] Optionally, as a feasible method, the extension directions of all ice crystal columns are parallel to each other; and / or the extension directions of all ice crystal branches are parallel to each other. Thus, the aerogel is composed of long branches and / or parallel branches arranged in a directional manner, and when heated by an external heat source, the aerogel material can exhibit excellent thermal insulation and compressibility.

[0307] As an example, the angle between the extension direction of all ice crystal branches and the extension direction of the ice crystal column is 60°, that is, all ice crystal branches are distributed in parallel on the ice crystal column.

[0308] Optionally, as a feasible method, a plurality of ice crystal branches on each ice crystal column are arranged in a circle around the ice crystal column, thereby improving the thermal insulation and compressibility of the aerogel material.

[0309] The thermal insulation aerogel material provided in the embodiment of the present application is tested and characterized as follows: Figures 17 to 21 Results shown.

[0310] First, thermal conductivity test

[0311] The thermal conductivity test of aerogel materials meets the international standard ISO 22007-2-2008 and is tested using a Hot Disk thermal conductivity tester.

[0312] First, a solid aerogel material is made, for example, at least two samples of the same size with a length and width greater than 20 mm×20 mm and a thickness less than 5 mm. At least one side of the sample is flat and can clamp the thermal probe.

[0313] Secondly, place the sample in the Hot Disk thermal conductivity tester, which can directly measure the thermal conductivity of the sample.

[0314] The thermal conductivity of the aerogel material measured in the embodiment of the present application along the longitudinal direction (y direction) ranges from 0.016W / (m•K) to 0.036W / (m•K). There is no specific limitation on the thermal conductivity of the aerogel material along the longitudinal direction. For example, the thermal conductivity of the aerogel material along the longitudinal direction may be 0.016W / (m•K), 0.020W / (m•K), 0.023W / (m•K), 0.026W / (m•K), 0.030W / (m•K) or 0.036W / (m•K), etc.

[0315] The thermal conductivity of the aerogel material measured in the embodiment of the present application along the transverse direction (z direction) ranges from 0.048W / (m•K) to 0.068W / (m•K). There is no specific limitation on the thermal conductivity of the aerogel material along the transverse direction. For example, the thermal conductivity of the aerogel material along the transverse direction may be 0.048W / (m•K), 0.050W / (m•K), 0.053W / (m•K), 0.058W / (m•K), 0.060W / (m•K) or 0.068W / (m•K), etc.

[0316] Furthermore, the thermal conductivity of the thermal insulation material in the longitudinal direction may be 0.026 W / (m·K), and / or the thermal conductivity in the transverse direction may be 0.058 W / (m·K).

[0317] However, the thermal conductivity of the conventional aerogel material provided in the related art may be 0.125 W / (m·K) in the longitudinal direction and 0.125 W / (m·K) in the transverse direction.

[0318] The aerogel material provided in the embodiment of the present application has a thermal conductivity coefficient in both longitudinal and transverse directions, especially a thermal conductivity coefficient in longitudinal direction, which is much lower than that of conventional aerogels. Therefore, when heated by an external heat source, the aerogel material can exhibit excellent thermal insulation and compressibility.

[0319] Second, compression performance test

[0320] The compression performance test of aerogel materials meets the international standard ISO 844 and is carried out using a compression testing machine.

[0321] First, a solid aerogel material is made, for example, at least two samples of the same size with a length and width greater than 20 mm×20 mm and a thickness less than 5 mm.

[0322] The sample is then placed in a compression tester and compressed along its principal axis at a constant displacement rate until the deformation reaches a certain percentage of the original sample height. The load must remain constant while measuring the sample deformation. The system can automatically calculate the required results and statistics by inputting the relevant data of the sample and setting the required control mode.

[0323] Fig.17 It is a schematic diagram of the result of repeated compression of the aerogel material provided in the embodiment of the present application.

[0324] exist Fig.17In the figure, the horizontal axis represents the compressive strain in %, and the vertical axis represents the compressive stress in MPa. Among them, 1st cycle refers to the strength curve corresponding to the first cycle of compression of the aerogel material, 5th cycle refers to the strength curve corresponding to the fifth cycle of compression of the aerogel material, and 10th cycle refers to the strength curve corresponding to the tenth cycle of compression of the aerogel material.

[0325] Depend on Fig.17 It can be seen that the aerogel material obtained by repeated freezing and thawing and thermal cross-linking shows excellent strength and compressibility in terms of mechanical properties. It can be compressed repeatedly, and there is no obvious dimensional change in strength after 10 times of compression. Moreover, more than 95% of the mechanical properties can be maintained after compression, with almost no performance degradation.

[0326] Third, heat conditions

[0327] Figures 18 to 21 It is a temperature distribution diagram on the surface and height direction of the material when the material is placed under the intensity of 1 sun.

[0328] in, Fig.18 This is a diagram of the heat-dissipating effect in the xz plane of the aerogel material provided in the embodiment of the present application when it is exposed to 1 sun intensity.

[0329] Fig.19 This is a diagram of the heat-averaging effect in the xz plane when a conventional aerogel material provided in the related art is placed under irradiation with a light intensity of 1 sun.

[0330] Fig. 20 This is a diagram of the heat uniformity effect in the y direction when the aerogel material provided in the embodiment of the present application is placed under irradiation with a light intensity of 1 sun.

[0331] Fig.21 This is a diagram of the heat-averaging effect in the y direction of a conventional aerogel material provided in the related art when placed under 1 sun intensity.

[0332] exist Fig.18 and Fig.19 In the equation, -1.0~1.0 represents the length of the xz plane in cm.

[0333] exist Fig. 20 and Fig.21 In the figure, 0.0~2.0 represents the height in the y direction, and the unit is cm.

[0334] Will Fig.18 and Fig.19 compared to, Fig.18 The dotted box represents the heat distribution size of the aerogel material provided in the embodiment of the present application in the xz plane. Fig.19The dotted box represents the heat distribution size of the conventional aerogel material provided in the related art in the xz plane. The heat distribution effect of the aerogel material provided in the embodiment of the present application and the conventional aerogel material provided in the related art in the xz plane is not much different.

[0335] However, Fig. 20 and Fig.21 compared to, Fig. 20 The dotted box represents the heat-dissipating effect of the aerogel material provided in the embodiment of the present application in the y direction. Fig.21 The dotted box represents the heat-dissipating effect of the conventional aerogel material provided in the related art in the y direction. The aerogel material provided in the embodiment of the present application has a better heat-dissipating effect in the y direction than the conventional aerogel material provided in the related art.

[0336] Therefore, compared with conventional aerogel materials, the penguin feather-mimicking aerogel provided in the embodiments of the present application exhibits a more excellent thermal insulation effect.

[0337] In summary, the thermal insulation material provided in the embodiment of the present application has a microstructure similar to that of penguin feathers, and has an extremely low longitudinal thermal conductivity, which can be as low as about 0.026 W / mk, which is much lower than conventional aerogel materials (about 0.125 W / mk), and when heated by an external heat source, the aerogel material imitating the penguin feather structure exhibits excellent thermal insulation performance; at the same time, in terms of mechanical properties, the aerogel material imitating the penguin feather structure has excellent compression resistance and can be compressed repeatedly; in addition, the aerogel material based on the imitation penguin feather structure has excellent flexibility and will not break easily.

[0338] Combine the following Figure 22 to Figure 26 , the electronic device 03 provided in the embodiment of the present application is introduced in detail.

[0339] Fig. 22 A schematic diagram of the structure of an electronic device 03 partially using the heat-insulating aerogel material provided by an embodiment of the present application is shown; Fig.23 A schematic structural diagram of another electronic device 03 partially using the thermal insulation aerogel material provided by an embodiment of the present application is shown.

[0340] in, Fig. 22 At position 1, a thermal insulation aerogel material is arranged inside the battery cover where the local protrusion of the battery FPC contacts the battery cover; and at position 2, a thermal insulation aerogel material is added between the mainboard bracket and the battery cover to solve the audio shell vibration problem and the heat insulation problem of the whole machine.

[0341] Fig.23 In order to prevent the plain leather battery cover from deforming under the extremely ultra-thin structure, thermal insulation aerogel material is set at the contact position between the BTB bracket and the battery cover.

[0342] It should be noted that Fig. 22 and Fig.23 Only the relevant positions and thermal insulation aerogel materials are marked, and the rest can be obtained by related technologies and will not be described in detail here.

[0343] The electronic device provided in the embodiment of the present application may include the above-mentioned aerogel material with a penguin feather-like structure. Since the aerogel material can withstand high temperatures, maintain a constant temperature, and is light in weight and high in strength, when heated by an external heat source, the aerogel material can exhibit excellent heat insulation and heat resistance. The aerogel material also has excellent compressibility, thereby enabling the electronic device to have a local heat insulation effect, reducing or avoiding the generation of local hot spots, improving the charging speed and thermal experience, and the overall performance of the electronic device is good.

[0344] Optionally, as a feasible method, in actual application, the electronic device also includes a battery, a battery cover and an adhesive, the battery cover has a first surface, the thermal insulation material is adhered to the first surface by the adhesive, and the first surface is used to face the battery when the battery and the battery cover are installed in the electronic device.

[0345] The electronic device provided in the embodiment of the present application uses an adhesive to adhere the insulating aerogel material to the inner surface of the battery cover and assemble it into a complete machine. For example, the insulating aerogel material can be added between the audio shell vibration foam and the battery cover, the battery cover at the corresponding position of the battery FPC, the plain leather back cover and the internal bracket, so as to prevent these structures from directly contacting the battery cover to transfer heat, reduce or avoid the generation of local hot spots, so as to avoid heat loss and improve the charging speed and thermal experience; at the same time, since the insulating aerogel material has excellent compressibility, it can be placed in these positions and make the electronic device miniaturized; in addition, the pressure-sensitive adhesive has good bonding strength with the insulating aerogel material and the battery cover, and the adhesive can be used to adhere the aerogel to the inner surface of the battery cover.

[0346] There is no particular limitation on the type of the adhesive. For example, the adhesive may be a pressure-sensitive adhesive or the like.

[0347] Specifically, first, a layer of pressure-sensitive adhesive can be brushed or directly adhered on the surface of the prepared solid thermal insulation aerogel material, and then cut into a size that matches the size of the hot spot position.

[0348] Secondly, during the assembly process, the thermal insulation aerogel material is attached to the surface of the battery cover corresponding to the battery position to obtain a battery cover assembly.

[0349] Finally, the integrated battery cover assembly is assembled with other components to obtain a complete machine, and a consumer electronic terminal product is obtained with the help of the thermal insulation material.

[0350] Please refer to the following Figure 24 to Figure 26, introduces three different scenarios in which the thermal insulation aerogel material provided in the embodiments of the present application is applied to electronic equipment 03.

[0351] Fig.24 The schematic diagram of the structure of the electronic device 03 in which the thermal insulation aerogel material provided in the embodiment of the present application is attached to the battery FPC protrusion and the inner surface of the battery cover.

[0352] like Fig.24 As shown, the thermal insulation aerogel material is attached to the contact position between the battery FPC protrusion and the inner surface of the battery cover by a pressure-sensitive adhesive. At this time, the thermal insulation aerogel material can withstand high temperatures and maintain a constant temperature, and it is light in weight and high in strength, thus providing good thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation properties, reducing or avoiding the occurrence of local hot spots between the battery FPC protrusion and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0353] Fig.25 The schematic diagram of the structure of the electronic device 03 in which the heat insulating aerogel material provided in the embodiment of the present application is adhered to the mainboard bracket and the inner surface of the battery cover is shown.

[0354] like Fig.25 As shown, the thermal insulation aerogel material is attached to the contact position between the mainboard bracket and the inner surface of the battery cover by a pressure-sensitive adhesive. At this time, the thermal insulation aerogel material can withstand high temperatures and maintain a constant temperature, and it is light in weight and high in strength, thus providing good thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation, reducing or avoiding the occurrence of local hot spots on the mainboard bracket and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0355] Fig.26 The schematic diagram of the structure of the electronic device 03 in which the thermal insulation aerogel material provided in the embodiment of the present application is attached to the BTB bracket and the inner surface of the battery cover is shown.

[0356] like Fig.26 As shown, the thermal insulation aerogel material is attached to the contact position between the BTB bracket and the inner surface of the battery cover by a pressure-sensitive adhesive. At this time, the thermal insulation aerogel material can withstand high temperatures and maintain a constant temperature, and is light in weight and high in strength, thereby providing good thermal insulation and heat protection capabilities. When heated by an external heat source, the aerogel material can exhibit excellent thermal insulation, reducing or avoiding the occurrence of local hot spots between the BTB bracket and the inner surface of the battery cover, thereby avoiding heat loss and improving the charging speed and thermal experience of electronic devices.

[0357] The description of the thermal insulation materials and the like in the embodiments of the present application can be referred to the above embodiments and will not be repeated here.

[0358] The above only introduces the contents related to the invention. The rest of the contents can be obtained by referring to the relevant technology and will not be described in detail here.

[0359] It should be understood that the above is only to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application. According to the above examples given, those skilled in the art can obviously make various equivalent modifications or changes. For example, some steps in each embodiment of the above detection method may be unnecessary, or some steps may be newly added. Or a combination of any two or any multiple embodiments of the above. Such modifications, changes or combined schemes also fall within the scope of the embodiments of the present application.

[0360] It should also be understood that the above description of the embodiments of the present application focuses on emphasizing the differences between the various embodiments. The same or similar points that are not mentioned can be referenced to each other. For the sake of brevity, they will not be repeated here.

[0361] It should also be understood that the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0362] It should also be understood that in the embodiments of the present application, "pre-setting" and "pre-definition" can be achieved by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including an electronic device), and the present application does not limit its specific implementation method.

[0363] It should also be understood that the division of the methods, situations, categories and embodiments in the embodiments of the present application is only for the convenience of description and should not constitute a special limitation. The features of various methods, categories, situations and embodiments can be combined without contradiction.

[0364] It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0365] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A thermal insulation material, characterized in that: include: An ice crystal base, wherein ice crystals in the ice crystal base are densely and continuously distributed along a first plane; An ice crystal unit, wherein the ice crystal unit comprises at least one ice crystal column, the ice crystal column extends in a direction perpendicular to the first plane, and ice crystals in the ice crystal column at a position where the ice crystal column contacts the ice crystal base are connected to ice crystals in the ice crystal base; the ice crystal column has a plurality of ice crystal branches, adjacent ice crystal branches are separated and arranged at intervals, a plurality of ice crystal branches on each ice crystal column are arranged in a circle around the ice crystal column, an angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column is an acute angle, and each ice crystal branch has a plurality of pores that are separated and distributed at intervals; The thermal conductivity of the thermal insulation material in a direction perpendicular to the first plane ranges from 0.016 W / (m•K) to 0.036 W / (m•K); The thermal conductivity of the thermal insulation material along a direction parallel to the first plane ranges from 0.048 W / (m·K) to 0.068 W / (m·K).

2. The thermal insulation material according to claim 1, characterized in that: The ice crystal unit includes a plurality of ice crystal columns, and an orientation channel is provided between adjacent ice crystal columns. The orientation channel extends in a direction perpendicular to the first plane, and the ice crystal branches are distributed in the orientation channel.

3. The thermal insulation material according to claim 2, characterized in that: Each of the orientation channels has a plurality of discrete and spaced-apart holes, and the width of the orientation channel along a direction parallel to the first plane ranges from 40µm to 60µm.

4. The thermal insulation material according to any one of claims 1 to 3, characterized in that: The shape of the orthographic projection of the pores on the ice crystal dendrites on the first plane is a circle, and the diameter of the circle is less than 1 µm.

5. The thermal insulation material according to any one of claims 1 to 3, characterized in that: The angle between the extension direction of each of the ice crystal branches and the extension direction of the ice crystal column ranges from 50° to 80°; and / or, The extension directions of all the ice crystal columns are parallel to each other.

6. The thermal insulation material according to any one of claims 1 to 3, characterized in that: The thermal insulation material is a thermal insulation aerogel material; The angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column is 60°.

7. An electronic device, characterized in that: The thermal insulation material comprises the thermal insulation material as claimed in any one of claims 1 to 6.

8. The electronic device according to claim 7, characterized in that: The electronic device also includes a battery, a battery cover and an adhesive, the battery cover has a first surface, the thermal insulation material is adhered to the first surface through the adhesive, and the first surface is used to face the battery when the battery and the battery cover are both installed in the electronic device.

9. The electronic device according to claim 8, characterized in that: The heat insulating material is attached to the contact position between the protrusion of the battery flexible circuit board and the first surface of the battery cover through the adhesive; And / or, the heat insulating material is adhered to the contact position between the mainboard bracket and the first surface of the battery cover by the adhesive; And / or, the heat insulating material is adhered to the contact position between the board-to-board connector bracket and the first surface of the battery cover through the adhesive.

10. A method for preparing a thermal insulation material, characterized in that: include: Dissolving polymer powder in water, adding filler and cross-linking agent and mixing evenly to obtain polymer aqueous solution; The polymer aqueous solution is freeze-thawed for multiple times to perform a cross-linking reaction to form a cross-linked hydrogel; wherein the temperature range of the freeze-thaw cycle of the polymer aqueous solution includes -50°C to 40°C; A mold is provided, which comprises a base and a mold cavity located on one side of the base; wherein one end of the mold cavity is fixed to the base and the other end is open, the material of the base comprises metal, and the base is immersed in liquid nitrogen; The cross-linked hydrogel is poured into the mold through the opening of the mold cavity, and the target thermal insulation material is obtained after freeze casting and freeze drying in sequence; wherein the cross-linked hydrogel contacts the base to form a tightly and continuously distributed ice crystal base, and grows at least one ice crystal column and a plurality of ice crystal branches on the ice crystal column in a direction perpendicular to the base, the ice crystals at the contact between the ice crystal column and the ice crystal base are connected to the ice crystals in the ice crystal base, the adjacent ice crystal branches are separated and spaced, and each ice crystal column has a plurality of ice crystal branches on it. The multiple ice crystal branches are arranged in a circle around the ice crystal column, the angle between the extension direction of each ice crystal branch and the extension direction of the ice crystal column is an acute angle, and each ice crystal branch has a plurality of discrete and spaced pores; the thermal conductivity of the thermal insulation material along the direction perpendicular to the first plane ranges from 0.016W / (m•K) to 0.036W / (m•K); the thermal conductivity of the thermal insulation material along the direction parallel to the first plane ranges from 0.048W / (m•K) to 0.068W / (m•K).

11. The method for preparing a thermal insulation material according to claim 10, characterized in that: The step of pouring the cross-linked hydrogel into the mold through the opening of the mold cavity, and sequentially performing freeze casting and freeze drying to obtain the target thermal insulation material comprises: pouring the cross-linked hydrogel into the mold through the opening of the mold cavity, and performing freeze casting and freeze drying in sequence to obtain a first thermal insulation material; The first thermal insulation material is heated to perform a thermal cross-linking reaction to obtain a target thermal insulation material; wherein the mechanical strength of the target thermal insulation material is greater than the mechanical strength of the first thermal insulation material.

12. The method for preparing a thermal insulation material according to claim 10 or 11, characterized in that: The temperature range of the freeze-thaw process includes -24°C to 30°C.

13. The method for preparing a thermal insulation material according to claim 10 or 11, characterized in that: The ratio of the mass of the polymer powder to the mass of the water ranges from 5% to 15%.

14. The method for preparing a thermal insulation material according to claim 10 or 11, characterized in that: The temperature range of the base includes -90°C to 20°C.

15. The method for preparing a thermal insulation material according to claim 10 or 11, characterized in that: The polymer powder includes at least one of polyvinyl alcohol powder, polyurethane powder and cellulose powder.

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