A heat pipe with high heat dissipation performance and its preparation method

Abstract

This invention discloses a heat pipe with high-efficiency heat dissipation performance and its preparation method. The heat pipe includes a metal outer shell, a liquid wick disposed on the inner wall of the metal outer shell, and a liquid working fluid filled within the metal outer shell. The liquid wick is a metal aerogel with a nanowire structure, the length direction of which is aligned with the length direction of the heat pipe. The heat pipe also includes a metal connecting layer disposed between the inner wall of the metal outer shell and the liquid wick to connect the metal outer shell and the liquid wick. The heat pipe of this invention has the advantages of rapid liquid absorption and efficient heat transfer, and can be used in the field of high-efficiency heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of heat conduction technology, and in particular to a heat pipe with high heat dissipation performance and its preparation method. Background Technology

[0002] With the continuous improvement of electronic device performance, heat dissipation has become one of the key factors restricting its development. Traditional heat dissipation technologies are no longer sufficient to meet the ever-increasing heat dissipation demands, especially in high-power-density applications. Heat pipes, as highly efficient heat conduction devices, are widely used in electronic device heat dissipation, LED lighting, aerospace, and other fields due to their excellent thermal conductivity. The wick is a crucial component of a heat pipe, primarily used to absorb liquid working fluid and transport it to the evaporation section. However, traditional wick materials for heat pipes, such as powders and fibers, often suffer from low thermal conductivity and limited wicking capacity, making heat pipes unsuitable for the needs of different application scenarios.

[0003] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a heat pipe with high heat dissipation performance and its preparation method.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, a heat pipe with high heat dissipation performance is provided, comprising a metal shell, a liquid absorber disposed on the inner wall of the metal shell, and a liquid working fluid filled in the metal shell. The liquid absorber is a metal aerogel with a nanowire structure, the length direction of the nanowire structure being consistent with the length direction of the heat pipe. The heat pipe further comprises a metal connecting layer disposed between the inner wall of the metal shell and the liquid absorber for connecting the metal shell and the liquid absorber.

[0007] In a second aspect, a method for preparing the heat pipe described in the first aspect is provided, comprising the following steps:

[0008] S1. Prepare a metal aerogel with a predetermined orientation of nanowire structure as a liquid absorbent core;

[0009] S2. A metal bonding layer is formed on the inner wall of a metal shell of a predetermined shape;

[0010] S3. Insert the metal aerogel into the metal shell with the length direction of the nanowire structure of the metal aerogel aligned with the length direction of the heat pipe, and then heat the heat pipe to above the melting point of the metal connecting layer so that the metal aerogel is fixed on the inner wall of the metal shell.

[0011] S4. Seal one end of the heat pipe, fill it with liquid working fluid and evacuate it;

[0012] S5. Seal the other end of the heat pipe.

[0013] The present invention has the following beneficial effects: The heat pipe of the present invention uses a metal aerogel with a nanostructure having specific orientation and superhydrophilic properties as the liquid wick. This orientation not only improves heat conduction and liquid absorption efficiency at the microscopic level, but can also be observed visually at the macroscopic level, thereby facilitating directional adjustment and optimization in practical applications to enhance the heat transfer efficiency of the heat pipe. The heat pipe has the advantages of rapid liquid absorption and efficient heat transfer (high heat dissipation performance) and can be used in the field of high-efficiency heat dissipation.

[0014] In some technical solutions, a low-temperature welding technique using a low-melting-point metal coating achieves a stable connection between the wick and the inner wall of the metal casing, reducing energy consumption and improving production efficiency. Furthermore, the metal aerogel wick possesses excellent resilience and adjustable shape and size, allowing the heat pipe to better adapt to the needs of different application scenarios. Attached Figure Description

[0015] Figure 1 This is a macroscopic image of the metal aerogel with a nanowire structure obtained in Example 2 of the present invention;

[0016] Figure 2A and Figure 2B The images are SEM images of the metal aerogel with nanowire structure in Example 2 of the present invention at different magnifications.

[0017] Figure 3 The results of the water absorption capacity test of the metal aerogel in Example 2 of the present invention;

[0018] Figure 4 The results of the ethanol adsorption capacity test of the metal aerogel in Example 2 of the present invention;

[0019] Figure 5 This is a schematic diagram of the cylindrical heat pipe in Embodiment 1 of the present invention;

[0020] Figure 6 This is a schematic diagram of the rectangular heat pipe in Embodiment 2 of the present invention;

[0021] Figure 7 The results show the compressibility test results of the metal aerogel in Example 2 of this invention. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope or application of the invention. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. In this document, M represents mol / L, and mM represents mmol / L.

[0023] This invention provides a heat pipe with high heat dissipation performance, comprising a metal shell, a liquid absorber disposed on the inner wall of the metal shell, and a liquid working fluid filled in the metal shell. The liquid working fluid is used for heat transfer in the heat pipe. The liquid absorber is a metal aerogel with a nanowire structure, the length direction of which is consistent with the length direction of the heat pipe. The heat pipe also includes a metal connecting layer disposed between the inner wall of the metal shell and the liquid absorber to connect the metal shell and the liquid absorber.

[0024] The metal aerogel with nanowire structure has a specific orientation (the length direction of each nanowire is basically consistent), thus exhibiting superhydrophilicity. The length direction of its nanowires is consistent with the length direction of the heat pipe (i.e., the two are parallel), which can significantly improve the heat pipe's liquid absorption and capillary suction capabilities, thereby enhancing the heat transfer efficiency of the heat pipe and achieving efficient mass transfer.

[0025] In some embodiments, the diameter of the nanowire structure is 1-5000 nm, preferably 200-2000 nm.

[0026] In some embodiments, the aspect ratio of the nanowire structure is 10. 7 :1-10 1 1. Preferably, the aspect ratio is 10. 6 :1-10 4 :1.

[0027] In some embodiments, the metal bonding layer is a low-melting-point metal plating layer with a melting point of 25°C-400°C.

[0028] In some embodiments, the metal aerogel is made of non-precious metals such as nickel, cobalt, iron, and copper or their alloys, or precious metals such as Au, Ag, Pt, and Pd or their alloys. More preferably, the metal aerogel with a nanowire structure is made of a ferromagnetic metal or metal alloy. Even more preferably, the metal aerogel with a nanowire structure is made of nickel, cobalt, iron, steel or their alloys.

[0029] In some embodiments, the low-melting-point metal is at least one of indium, tin, bismuth, gallium, and zinc; and the thickness of the low-melting-point metal coating is 50 nm to 1 mm.

[0030] In some embodiments, the metal aerogel is welded to the low-melting-point metal plating on the inner wall of the metal shell to form a stable connection. Preferably, the welding temperature is 1-400°C above the melting point of the metal bonding layer and less than 500°C.

[0031] In some embodiments, the porosity of the metal aerogel with nanowire structure is 30%-99%. The porosity of the metal aerogel's liquid-absorbing core enhances its liquid absorption and heat transfer performance. The metal aerogel with nanowire structure has elastic properties and can rebound after compression, which can ensure that the heat pipe does not experience structural collapse or irreversible deformation during use.

[0032] In some embodiments, the metal shell is made of a metal with good electrical conductivity, such as silver, copper, aluminum, or stainless steel, or an alloy thereof. For example, the required tubular shape is formed by common metal forming methods, including stretching, stamping, welding, casting, powder metallurgy, CNC machining, and 3D printing.

[0033] In some embodiments, the liquid working fluid is a conventional heat pipe working fluid such as water, ethanol, methanol, or acetone. Preferably, the liquid working fluid is water and ethanol.

[0034] In some embodiments, when the liquid working fluid contains water and the standard electrode potential of the metal on the inner surface of the heat pipe is lower than 0V, the inner surface of the heat pipe in contact with water also has a layer of metal with a standard electrode potential greater than 0V. For example, electroplating or chemical plating can be used to plate the inner surface of the heat pipe in contact with water (the surface containing metal aerogel and other exposed surfaces inside the heat pipe) with a metal (e.g., copper, silver, bismuth, gold, etc.) to ensure the long-term, efficient heat dissipation stability of the heat pipe. A specific embodiment of the present invention also provides a method for preparing the aforementioned heat pipe, which includes the following steps:

[0035] S1. Prepare a metal aerogel with a predetermined orientation of nanowire structure as a liquid absorbent core;

[0036] S2. A metal bonding layer is formed on the inner wall of a metal shell of a predetermined shape;

[0037] S3. Insert the metal aerogel into the metal shell with the length direction of the nanowire structure of the metal aerogel aligned with the length direction of the heat pipe. Then heat the heat pipe to above the melting point of the metal connecting layer to fix the metal aerogel to the inner wall of the metal shell. Specifically, observe the side of the metal aerogel with clear macroscopic orientation and adjust the orientation of the metal aerogel so that its macroscopic orientation is parallel to the direction of the heat pipe. This makes the nanowire structure of the aerogel parallel to the length direction of the heat pipe. Insert several metal aerogels into the heat pipe in the above direction so that the nanowire structure of the aerogel is parallel to the heat pipe. Then heat the heat pipe to 1-400°C above the melting point of the metal connecting layer but less than 500°C to weld and fix the metal aerogel to the inner surface of the heat pipe.

[0038] S4. Seal one end of the heat pipe (e.g., by welding the seal with low-temperature solder), fill it with liquid working fluid, and evacuate it.

[0039] S5. Seal the other end of the heat pipe (e.g., by welding a seal with low-temperature solder).

[0040] In some embodiments, in step S1, the metal aerogel is prepared by a sol-gel method combined with a magnetic field induction step. The sol-gel method can precisely control the formation of nanowires, and the magnetic field induction step can guide the nanowires to align in a specific direction, thereby obtaining a metal aerogel with typical orientation characteristics. This orientation of the metal aerogel can be observed visually at a macroscopic level, and the nanowires can be aligned along the length of the heat pipe by selectively adjusting the position of the aerogel.

[0041] In some embodiments, the metal aerogel is a nickel aerogel, and its preparation includes the following steps:

[0042] (1) Prepare solution A of 0.01-10M nickel salt, 0.01-10M complexing agent, and 0.01-10mM H2PtCl6; wherein, preferably, the nickel salt is at least one of NiCl2, nickel sulfate, nickel acetate, and nickel nitrate, the complexing agent is citrate or organic acid, preferably the citrate is Na3C6H5O7, and the organic acid is at least one of ethylenediaminetetraacetic acid and tartaric acid;

[0043] (2) Prepare a solution B by mixing the reducing agent with deionized water, wherein the concentration of the reducing agent in solution B is 0.1-30 vol.%, wherein, preferably, the reducing agent is at least one of hydrazine hydrate, oxalic acid, sodium borohydride, and sodium hypophosphite;

[0044] (3) Adjust the pH of solution A and solution B to 7-14 respectively, for example, by using alkaline solutions such as KOH, NaOH, Ba(OH)2 to adjust the pH of solution A and solution B to 7-14;

[0045] (4) Preheat solutions A and B to the reaction temperature respectively; preferably, the reaction temperature is 30-100℃;

[0046] (5) According to the molar ratio of nickel salt in solution A to reducing agent in solution B of 2:1-1:20, mix solution A and solution B in a mold of a predetermined shape (the inner wall dimensions (length, width, height, diameter, etc.) of the mold are slightly larger than the inner diameter of the heat pipe) and place the mold in a water bath to maintain the temperature at the reaction temperature;

[0047] (6) Place the entire reaction apparatus from step (5) into the Helmholtz coil, ensuring that the mold containing solution A and solution B is centered in the Helmholtz coil. Apply current and adjust the current to adjust the magnetic induction intensity to a predetermined value, and react to obtain a nickel aerogel with a predetermined orientation. Preferably, the magnetic induction intensity is 50-2000 Gs, and the reaction time is 1-120 min. More preferably, the magnetic induction intensity is 50-500 Gs, and the reaction time is 50-120 min.

[0048] (7) Wash the obtained nickel aerogel repeatedly with deionized water until the pH of the washing solution is neutral, and then dry the washed nickel aerogel in air (e.g., dry for 48 hours) to obtain nickel aerogel of the predetermined shape and size.

[0049] Besides the sol-gel method mentioned above, nanowire structures can also be prepared using dealloying, template methods, and 3D printing. The size and shape of the outer shell can be adjusted according to actual application requirements, and the shape of the metal aerogel can also be adjusted according to the specific design and application requirements of the heat pipe. The shape and size of the metal aerogel are controllable during preparation, allowing for a shape that perfectly matches the inner surface of the heat pipe. For example, when the heat pipe is rectangular, the dimensions of the rectangular wick can be: thickness 0.2-100 mm, width 0.2-100 mm, and length 0.2-1000 mm; when the heat pipe is cylindrical, the dimensions of the cylindrical wick can be: diameter 0.2-100 mm and length 0.2-1000 mm.

[0050] In some implementations, step S2 includes the following steps:

[0051] S21. Clean the inner surface of the metal casing; for example, by ultrasonic cleaning or chemical cleaning agents.

[0052] S22. Using a plating solution containing the metal elements in the metal bonding layer (the plating solution includes metal salts, complexing agents, reducing agents, stabilizers, etc.), a coating of a predetermined thickness is plated on the inner surface of the metal casing. Preferably, the plating method is at least one of chemical plating, electroplating, and coating. More preferably, the plating method is chemical plating.

[0053] S23. The product obtained from the cleaning and drying steps of S22.

[0054] In some embodiments, when the liquid working fluid contains water and the standard electrode potential of the metal on the inner surface of the heat pipe is lower than 0V, the method further includes forming a layer of metal with a standard electrode potential greater than 0V on the inner surface of the heat pipe in contact with water. For example, electroplating, chemical plating, or other methods are used to plate the inner surface of the heat pipe in contact with water (the surface containing metal aerogel and other exposed surfaces inside the heat pipe, etc.) with the metal with a standard electrode potential greater than 0 (e.g., copper, silver, bismuth, gold, etc.) to ensure the long-term efficient heat dissipation stability of the heat pipe.

[0055] The metal aerogel of this invention has a nanowire microstructure, and the orientation of the nanowire structure is achieved through specific growth techniques (e.g., magnetic field induction). This orientation not only improves heat conduction and liquid absorption efficiency at the microscopic level but also can be observed visually at the macroscopic level, facilitating directional adjustment and optimization in practical applications. By implementing this invention, not only can the heat dissipation efficiency of heat pipes be improved, but the size and shape of the liquid absorbent core and the overall structure of the heat pipe can also be adjusted according to specific application requirements, thereby achieving a more flexible and efficient heat dissipation solution. The implementation of these technologies is expected to provide strong support for efficient heat dissipation in fields such as electronic devices, LED lighting, and aerospace.

[0056] The following further describes specific embodiments of the present invention. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels, and the processes used are conventional processes in the art.

[0057] Example 1

[0058] Cylindrical heat pipes with superhydrophilic nickel aerogel as the wicking core, such as... Figure 5 As shown. The fabrication of this heat pipe includes the following steps:

[0059] (1) A circular copper tube 1 is obtained by using a copper sheet with a thickness of 0.15mm and processing it through conventional forming methods.

[0060] (2) Clean the inner surface of copper tube 1 using ultrasonic or chemical cleaning agents.

[0061] (3) Chemically plating an indium layer 2 onto the inner surface of the above-mentioned circular copper tube 1, specifically including the following steps:

[0062] a. Add 2.27g of indium sulfate powder to deionized water, add 20ml of dilute sulfuric acid (10wt.%) to aid dissolution, stir and shake until the solution is clear and transparent to obtain solution A;

[0063] b. Weigh 3.36g of disodium ethylenediaminetetraacetate, 0.6g of hydroquinone, and 3g of triethanolamine, dissolve them separately in deionized water, and stir after the solutes are completely dissolved to obtain solution B;

[0064] c. Prepare several milliliters of NaOH solution with a concentration of 2 g / ml as a pH adjuster for later use;

[0065] d. Mix solution A with solution B and stir. Adjust the pH of the plating solution to between 9.0 and 10.0 at room temperature using sodium hydroxide solution. Stir the solution continuously during pH adjustment. After stirring until homogeneous, obtain mixture C.

[0066] e. Weigh 2g of sodium borohydride and dissolve it in 20mL of deionized water to obtain solution D for later use;

[0067] f. Cover the outer surface of copper tube 1 with a protective film to prevent contact with the plating solution. Pour the mixture C into the container containing copper tube 1 and place it in a magnetic stirrer heated to 80°C for continuous electromagnetic stirring. Use a burette to titrate solution D into the solution at a titration rate of 1 mL / min. After titration, react for another 10 min to obtain an indium plating layer 2 on the inner surface of copper tube 1.

[0068] g. Remove the copper tube, remove the protective film from the outer surface of the heat pipe, clean it with water and ethanol, dry it, and set it aside for later use.

[0069] (4) Prepare nickel aerogel 3 with a nanowire structure as a liquid absorbent core. This includes the following steps:

[0070] a. Prepare solution A containing 0.35M NiCl2, 0.12M Na3C6H5O7, and 0.3mM H2PtCl6;

[0071] b. Add a certain amount of hydrazine hydrate to deionized water to prepare solution B, wherein the concentration of hydrazine hydrate is 8.5 vol.%.

[0072] c. Then use 6M KOH solution to adjust the pH of solutions A and B to 13;

[0073] d. Add 25 mL of solution A and 25 mL of solution B to two beakers respectively, and place them in an 80°C water bath for 5 min to preheat the beakers to the same temperature as the reaction process.

[0074] e. At the start of the reaction, mix solution A and solution B into an 80mL custom-made round glass mold (the inner wall size of the mold is slightly larger than the inner diameter of the copper tube), stir quickly and thoroughly, and then place it in an 80℃ water bath.

[0075] f. Place the entire reaction apparatus into the center of the Helmholtz coil, energize it, and adjust the current to achieve a magnetic induction intensity of 300 Gs. The reaction time is 48 min. After the reaction is complete, nickel aerogel 3 is obtained.

[0076] g. The obtained nickel aerogel 3 is repeatedly washed with deionized water until the pH of the washing solution is neutral. Then, the washed hydrogel is air-dried for 48 hours to obtain a cylindrical nickel aerogel 3 of a certain size.

[0077] (5) Observe the side of the metal aerogel with clear macroscopic orientation and adjust the position of the metal aerogel so that its macroscopic orientation is parallel to the direction of the heat pipe. This will make the nanowire structure of the aerogel parallel to the length direction of the heat pipe. Insert several of the above-mentioned nickel aerogels 3 into the indium-plated copper tube and heat them to above the melting point of indium (170-180℃) so that the metal aerogel is welded and fixed to the inner surface of the heat pipe.

[0078] (6) A copper metal layer is plated on the inner surface of the heat pipe using a general chemical copper plating method;

[0079] (7) Seal one end of the heat pipe with low-temperature solder, fill it with water as the liquid working medium and evacuate it;

[0080] (8) A closed heat pipe is formed by welding the other end of the heat pipe with low-temperature solder.

[0081] Example 2

[0082] Rectangular heat pipes with superhydrophilic nickel aerogel as the wicking core, such as... Figure 6 As shown, the fabrication of this heat pipe includes the following steps:

[0083] (1) A rectangular copper tube 1 is obtained by using a copper sheet with a thickness of 0.3 mm and processing it through conventional forming methods.

[0084] (2) Clean the inner surface of the rectangular copper tube 1 using ultrasonic or chemical cleaning agents.

[0085] (3) A tin layer 2 is chemically deposited on the inner surface of the above-mentioned circular copper tube 1. The chemical tin plating solution used in this example is the HSN-800 series from Shenzhen Hongxi Technology Development Co., Ltd. According to the tin plating process provided by the company, the tin plating process in this example includes the following steps:

[0086] a. Remove oil and clean the surface of copper tube 1 to ensure it is free of oil, rust or other impurities;

[0087] b. Micro-etching: Immerse copper tube 1 in a 10% hydrochloric acid solution for 2 to 3 minutes. During this process, the outer surface of copper tube 1 should be covered with a protective film to prevent contact with the corrosion solution and the plating solution in the subsequent process.

[0088] c. Pre-immersion: Prepare the pre-immersion solution according to the following concentrations (volume%, % v / v): 94% immersion tin starter HSN-800M, 4.5% tin concentrate TIN-300, 1.5% immersion tin additive HSN-800Add, stir thoroughly and evenly, and pre-treat the above heat pipes in the pre-immersion solution for 30s.

[0089] d. Tin immersion: Prepare the tin immersion solution according to the following concentrations (volume%, % v / v): 47% tin immersion tank starter HSN-800M, 2.25% tin concentrate TIN-300, and 0.75% tin immersion additive HSN-800Add. Stir thoroughly and evenly, and place the heat pipe in the tin immersion solution for 180 seconds to obtain a tin plating layer on the inner surface of the copper pipe 1.

[0090] e. Remove the copper tube 1, remove the protective film on the outer surface of the heat pipe, clean it with water and ethanol, dry it, and set it aside for later use.

[0091] (4) Prepare nickel aerogel 3 with a nanowire structure as a liquid absorbent core. This includes the following steps:

[0092] a. Prepare solution A containing 0.35M NiCl2, 0.12M Na3C6H5O7, and 0.30mM H2PtCl6;

[0093] b. Add a certain amount of hydrazine hydrate to deionized water to prepare solution B, wherein the concentration of hydrazine hydrate is 8.5 vol.%.

[0094] c. Adjust the pH of solutions A and B to 13 using a 6M KOH solution;

[0095] d. Add 30 mL of solution A and 30 mL of solution B to two beakers respectively, and preheat them in an 80°C water bath for 5 min to make the preheating temperature the same as the reaction temperature.

[0096] e. At the start of the reaction, mix solutions A and B into a 100mL custom square glass mold (the inner wall size of the mold is slightly larger than the inner diameter of the copper tube), stir quickly and thoroughly, and then place it in an 80℃ water bath.

[0097] f. Place the entire reaction apparatus into the center of the Helmholtz coil, energize it, and adjust the current to achieve a magnetic induction intensity of 300 Gs. The reaction time is 60 min. After the reaction is complete, nickel aerogel 3 is obtained.

[0098] g. The obtained nickel aerogel 3 is repeatedly washed with deionized water until the pH of the washing solution is neutral. Then, the washed hydrogel is air-dried for 48 hours to obtain a square nickel aerogel 3 of a certain size.

[0099] (5) Insert several of the above-mentioned nickel aerogels 3 into the copper tube 1 and heat them to above the melting point of tin, so that the aerogels are welded and fixed to the inner surface of the heat pipe.

[0100] (6) A copper metal layer is plated on the inner surface of the heat pipe using a general chemical copper plating method;

[0101] (7) Seal one end of the heat pipe with low-temperature solder, fill it with ethanol as a liquid working medium and evacuate it.

[0102] (8) A closed heat pipe is formed by welding the other end of the heat pipe with low-temperature solder.

[0103] like Figure 1 The image shown is a macroscopic image of the metal aerogel with a nanowire structure prepared in this embodiment. Figure 2A and 2B The image shown is a SEM image of the metal aerogel with nanowire structure prepared in this embodiment at different magnifications. Figure 3 The results of the water absorption capacity test of the metal aerogel in this embodiment (including before oxidation and after oxidation in air at 150°C for 1 hour, with pure water added on top of the metal aerogel) show that the water absorption and hydrophilicity of the absorbent core did not change before and after oxidation (water was absorbed very quickly within 0.05s). This means that the experiment proves that even if the metal aerogel is oxidized, it still has strong water absorption and hydrophilicity. Figure 4 The results of the ethanol adsorption capacity test of the metal aerogel in this embodiment (including before oxidation and after oxidation in air at 150°C for 1 hour, with anhydrous ethanol added above the metal aerogel) show that the absorbent core exhibits superalcoholic and strong ethanol adsorption characteristics (ultra-fast ethanol adsorption within 0.05 s) before and after oxidation. This demonstrates that even after oxidation, the metal aerogel still possesses strong alcoholic and strong ethanol adsorption characteristics. Figure 7 The results of the compression resistance test of the metal aerogel in this embodiment are shown, proving that it has good elastic properties.

[0104] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A heat pipe with high heat dissipation performance, comprising a metal outer shell, a liquid wick disposed on the inner wall of the metal outer shell, and a liquid working fluid filled into the metal outer shell, characterized in that, The absorbent core is a metal aerogel with a nanowire structure. The metal aerogel has a porosity of 30%-99% and elastic properties. The length direction of the nanowire structure is consistent with the length direction of the heat pipe. The heat pipe also includes a metal connecting layer, which is disposed between the inner wall of the metal shell and the absorbent core to connect the metal shell and the absorbent core. The metal connecting layer is a low-melting-point metal coating with a melting point of 25℃-400℃. The metal aerogel and the low-melting-point metal coating are firmly connected by welding. The method for preparing the heat pipe includes the following steps: S1. Prepare a metal aerogel with a predetermined orientation of nanowire structure as a liquid absorbent core; the metal aerogel is a nickel aerogel, and its preparation includes the following steps: (1) Prepare solution A containing 0.01-10 M nickel salt, 0.01-10 M complexing agent, and 0.01-10 mM H2PtCl6; (2) Prepare solution B by mixing the reducing agent with deionized water, wherein the concentration of the reducing agent in solution B is 0.1-30 vol.%. (3) Adjust the pH of solutions A and B to 7-14 respectively; (4) Preheat solutions A and B to the reaction temperature respectively; (5) According to the molar ratio of nickel salt in solution A to reducing agent in solution B of 2:1-1:20, mix solution A and solution B in a mold of a predetermined shape and place the mold in a water bath to maintain the temperature at the reaction temperature; (6) Place the entire reaction apparatus from step (5) into the Helmholtz coil, ensuring that the mold containing solution A and solution B is at the center of the Helmholtz coil, energize and adjust the current to adjust the magnetic induction intensity to a predetermined value, and react to obtain a nickel aerogel with a predetermined orientation. (7) Wash the obtained nickel aerogel repeatedly with deionized water until the pH of the washing solution is neutral, and then dry the washed nickel aerogel in the air to obtain nickel aerogel of the predetermined shape and size. S2. A metal bonding layer is formed on the inner wall of a metal shell of a predetermined shape; S3. Insert the metal aerogel into the metal shell with the length direction of the nanowire structure of the metal aerogel aligned with the length direction of the heat pipe, and then heat the heat pipe to above the melting point of the metal connecting layer so that the metal aerogel is fixed on the inner wall of the metal shell. S4. Seal one end of the heat pipe, fill it with liquid working fluid and evacuate it; S5. Seal the other end of the heat pipe.

2. The heat pipe as described in claim 1, characterized in that: The diameter of the nanowire structure is 1-5000 nm.

3. The heat pipe as described in claim 1, characterized in that: The aspect ratio of the nanowire structure is 10. 7 :1-10 1 :

1.

4. The heat pipe as described in claim 1, characterized in that: The diameter of the nanowire structure is 200-2000 nm.

5. The heat pipe as described in claim 1, characterized in that: The nickel salt is at least one of NiCl2, nickel sulfate, nickel acetate, and nickel nitrate; the complexing agent is citrate or organic acid; the reducing agent is at least one of hydrazine hydrate, oxalic acid, sodium borohydride, and sodium hypophosphite; in step (6), the magnetic induction intensity is 50-2000 Gs, and the reaction time is 1-120 min.

6. The heat pipe as claimed in claim 1, characterized in that: The low-melting-point metal is at least one of indium, tin, bismuth, gallium, and zinc; the thickness of the low-melting-point metal coating is 50 nm - 1 mm.

7. The heat pipe as claimed in claim 1, characterized in that: When the liquid working fluid contains water and the standard electrode potential of the metal on the inner surface of the heat pipe is lower than 0V, the inner surface of the heat pipe in contact with the water also has a layer of metal with a standard electrode potential greater than 0V.

8. The heat pipe as claimed in claim 1, characterized in that: The aspect ratio of the nanowire structure is 10. 6 :1-10 4 :

1.

9. The heat pipe as described in claim 5, characterized in that, In step (1), the citrate is Na3C6H5O7, and the organic acid is at least one of ethylenediaminetetraacetic acid and tartaric acid; in step (4), the reaction temperature is 30-100℃; in step (6), the magnetic induction intensity is 50-500 Gs, and the reaction time is 50-120 min.

10. The heat pipe as claimed in claim 1, characterized in that, Step S2 includes the following steps: S21. Clean the inner surface of the metal casing; S22. A plating solution containing the metal elements in the metal connecting layer is used to plate a coating of a predetermined thickness on the inner surface of the metal casing, wherein the plating method is at least one of chemical plating, electroplating, and coating. S23. The product obtained from the cleaning and drying steps of S22.

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