Monodisperse reverse-type core-shell structure phase change heat storage microcapsule and preparation device and method thereof

Abstract

The application provides a monodisperse reverse core-shell structure phase change heat storage microcapsule and a preparation device and method thereof, and relates to the technical field of phase change heat storage materials. The phase change heat storage microcapsule comprises a shell and a core arranged inside the shell, the shell is a high-melting-point alloy, and the core is a low-melting-point alloy. The method of the application realizes accurate regulation of the liquid droplet ejection behavior and the core-shell structure formation process by adjusting the rising edge time parameter of the pulse driving signal; the piezoelectric driving system has the characteristics of fast response speed, high control precision and good vibration stability, so that the disturbance mode of the transmission rod to the alloy melt can be effectively changed, thereby improving the stability of the liquid droplet formation and ejection process.

Description

Technical Field

[0001] This invention relates to the field of phase change thermal energy storage technology, and more particularly to a monodisperse reversible core-shell structure phase change thermal energy storage microcapsule and its preparation apparatus and method. Background Technology

[0002] In the fields of medium- and high-temperature thermal storage and high-power thermal management, metals and their alloys exhibit unique advantages due to their high thermal conductivity and volumetric heat storage density. Phase change microcapsules, by encapsulating metal phase change materials within an outer shell, effectively solve the problems of fluidity and corrosion of metal phase change materials, making them particularly suitable for large-scale applications. Microcapsules are essentially core-shell structured particles, with a low-melting-point phase serving as the heat storage core and a high-melting-point phase as the protective shell. When the material is heated to between the melting points of the two phases, the core phase melts and absorbs heat, while the shell remains stable; during cooling, the core re-solidifies and releases latent heat, thus achieving heat energy storage and release. Currently, microcapsules mostly use ceramic shells to encapsulate metal phase change materials. However, these microcapsules are prone to ceramic shell damage during thermal cycling, leading to liquid metal leakage, which to some extent restricts their engineering applications. Using metal encapsulation can effectively solve this problem. This encapsulation method uses a metal shell to encapsulate the metal phase change material. The metal shell not only effectively isolates the material but also provides excellent mechanical strength and high-temperature resistance. Common metal materials include stainless steel and aluminum alloys.

[0003] Existing industrial preparation methods mainly rely on electroplating or coating processes to form core-shell structures. However, these methods suffer from drawbacks such as complex processes, long preparation cycles, high costs, and difficulty in achieving large-scale continuous production. Therefore, developing a method for preparing monodisperse phase change thermal storage microcapsules with uniform particle size, high sphericity, stable core-shell structures, and controllable morphology has significant theoretical and engineering application value.

[0004] In recent years, the liquid-liquid phase separation and elemental segregation behavior exhibited by phase-separated crystalline alloys during rapid solidification has attracted widespread attention. Studies have found that these alloys can form particles with core-shell structure characteristics through phase separation in the metastable, immiscible region; that is, one component forms the core, and another component coats the outer layer to form the shell.

[0005] Currently, research institutions both domestically and internationally have employed techniques such as gas atomization, drop-tube method, jet fracture method, and traditional casting to prepare miscible interstitial alloy core-shell structured particles, achieving some progress. However, due to inconsistent droplet cooling conditions in these methods, significant differences in the thermal history during particle solidification occur, making it difficult to achieve stable formation and precise control of the core-shell structure. This often results in problems such as wide particle size distribution, insufficient sphericity, and uncontrollable core-shell thickness, sometimes even preventing the formation of a complete core-shell structure. Moreover, practical phase change thermal energy storage capsules generally require a larger proportion of the thermal energy storage core to store more thermal energy. However, miscible interstitial alloys that meet this requirement often yield conventional core-shell structured particles with a low-melting-point phase as the shell and a high-melting-point phase as the core under conventional conditions. This structure clearly does not meet the structural and compositional requirements of phase change thermal energy storage microcapsules. Therefore, there is an urgent need for a method to prepare inverted core-shell structured particles where all particles have a high-melting-point shell and a low-melting-point core for use as phase change thermal energy storage capsules. Summary of the Invention

[0006] To address the aforementioned technical problems, a monodisperse reversible core-shell structured phase change thermal storage microcapsule and its preparation apparatus and method are provided.

[0007] The technical means employed in this invention are as follows:

[0008] A monodisperse reversible core-shell phase change thermal storage microcapsule includes: an outer shell and a core disposed inside the outer shell, wherein the outer shell is a high-melting-point alloy and the core is a low-melting-point alloy.

[0009] This invention also provides a preparation apparatus for monodisperse reversible core-shell structure phase change thermal storage microcapsules, which is used to prepare monodisperse reversible core-shell structure phase change thermal storage microcapsules, including: piezoelectric ceramic, transmission rod, infrared thermometer, ceramic sheet, molecular pump, mechanical pump, particle collector, drop tube, vacuum chamber, pre-collection disk, high-speed camera, crucible, heating coil, differential pressure controller, computer, crucible inlet pipe and signal generator; The heating coil is disposed on the outer wall of the crucible, the crucible is disposed above the interior of the vacuum chamber, the transmission rod is inserted into the alloy melt inside the crucible through the top of the vacuum chamber, the upper end of the transmission rod protruding from the vacuum chamber is connected to the piezoelectric ceramic, the ceramic plate is disposed at the bottom of the interior of the crucible, the bottom center of the crucible has a through hole, the center of the ceramic plate has a micro hole, the micro hole is connected to the interior cavity of the crucible and the through hole; The pre-collection disk is installed inside one side of the vacuum chamber. The bottom of the vacuum chamber is connected to the drop tube, and the bottom of the drop tube is connected to the particle collector. The drop tube is located directly below the micropore. The piezoelectric ceramic is connected to a signal generator, which is electrically connected to a computer. The computer is electrically connected to a differential pressure controller, which is connected to one end of the crucible inlet pipe. The other end of the crucible inlet pipe is inserted into the crucible through the side wall of the vacuum chamber. The computer is also electrically connected to a high-speed camera, which is mounted on one side wall of the vacuum chamber. The infrared thermometer is mounted on the other side wall of the vacuum chamber. The mechanical pump is connected to a molecular pump, which is connected to the vacuum chamber.

[0010] This invention also provides a method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules, using the above-mentioned preparation apparatus, comprising the following steps: Step 1, Loading and Vacuuming: After cleaning and drying the metal raw materials, weigh and mix them according to the set proportions, and load them into a crucible. Set up heating coils around the crucible. When using the equipment, first start the mechanical pump to pre-evacuate the vacuum chamber and crucible, then turn on the molecular pump to further extract gas from the vacuum chamber and crucible to achieve a high vacuum state. After the set vacuum conditions are reached, turn off the mechanical pump and slowly fill the vacuum chamber with high-purity inert gas through the crucible inlet pipe until the system pressure returns to the atmospheric pressure level to create a stable, low-oxygen atmosphere. Step 2, Melt Processing: After turning on the pre-collection tray, connect the infrared thermometer and heat the metal raw materials in the crucible by adjusting the input current of the heating coil. Melt the mixed metal raw materials and hold the temperature for 20 minutes to promote complete melting and homogenization of the composition, resulting in an alloy melt. During the heating process, the melt state is judged by gradually adjusting the position of the transmission rod. Once it is confirmed that the metal raw materials have completely melted, adjust the system temperature to the target temperature and continue to hold the temperature for 20 minutes to ensure a stable and uniform temperature field distribution inside the alloy melt. In addition, the transmission rod is appropriately immersed in the alloy melt for synchronous heating to reduce its disturbance to the local temperature field. At the same time, inert gas is introduced into the crucible through the crucible inlet pipe to create a pressure difference of 1~4 Torr between the inside of the crucible and the vacuum chamber. Step 3: Turn on the signal generator and set the pulse drive signal. Under the condition of adjusting the rise time parameter of the pulse drive signal, the output electrical signal is applied to the piezoelectric ceramic, causing it to generate periodic vibrations with different response characteristics, and further driving the transmission rod to reciprocate. The alloy melt at the bottom of the crucible is acted upon by the transmission rod, causing the liquid to be ejected from the micropores to form droplets. As the rise time parameter changes, the disturbance intensity of the alloy melt and the droplet ejection state change accordingly, thereby realizing the control of droplet formation and solidification behavior. During the process, the output voltage waveform is monitored and dynamically adjusted in real time by a computer to ensure the stability of the droplet ejection process. At the same time, a high-speed camera is used to capture and record the droplet formation, contraction and cooling solidification process in real time. During the rapid cooling process, the ejected droplets first form incompletely solidified phase-separated particles, and further complete containerless solidification during free fall, finally forming core-shell structured particles. Step 4, Particle Collection: The jet-formed droplets cool and solidify in a drop tube filled with inert gas, and finally settle into the bottom particle collector. The particle collector is equipped with multiple independent collection areas. During the process, by changing the rise time parameter, core-shell structured microparticles obtained under different conditions are collected and classified for preservation, thereby improving the specificity of sample analysis and the comparability of results. After particle preparation is completed, the piezoelectric ceramic, infrared thermometer and heating coil are turned off in sequence. After the device cools to room temperature, inert gas is introduced into the vacuum chamber to restore it to atmospheric pressure. The particle collector is then turned on to collect the prepared core-shell structured particles. The device is then evacuated again for the next preparation.

[0011] Furthermore, in step 1, after pre-evacuation, the pressure in the vacuum chamber is reduced to below 4 Pa; the vacuum level under high vacuum conditions is below 4 × 10⁻⁶ Pa. -3 Pa.

[0012] Furthermore, in step 2, when heating the metal raw material, the heating temperature is 10 to 80°C higher than the alloy liquidus temperature.

[0013] Furthermore, in step 4, the rise time is 100 μs.

[0014] Compared with the prior art, the present invention has the following advantages: 1. The preparation method of this invention is based on the principle of combining pulsed micro-orifice jetting with rapid solidification. By adjusting the rise time parameter of the pulse drive signal, precise control of droplet jetting behavior and core-shell structure formation process can be achieved. Utilizing the characteristics of fast response speed, high control precision, and good vibration stability of the piezoelectric drive system, the disturbance mode of the transmission rod on the alloy melt can be effectively changed, thereby improving the stability of droplet formation and jetting processes.

[0015] 2. Compared with traditional droplet preparation methods, this invention can spray and form droplets with more uniform particle size distribution, higher sphericity, and better stability, and achieve liquid-liquid phase separation and in-situ formation of inverted core-shell structures during rapid cooling. The prepared microparticles have advantages such as intact core-shell structure, uniform size, good surface quality, and high thermal stability, which can effectively improve the preparation efficiency and product quality of core-shell phase change thermal storage microparticles.

[0016] 3. The preparation device of the present invention has a simple structure, good process continuity, and convenient parameter adjustment. It can meet the needs of stabilization and large-scale preparation of monodisperse core-shell structured microparticles and has good application prospects in the fields of phase change thermal storage, electronic thermal management and core-shell composite functional materials.

[0017] Based on the above reasons, this invention can be widely applied in fields such as the preparation of phase change thermal storage microcapsules. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the device for preparing monodisperse core-shell structure phase change thermal storage microcapsules according to the present invention.

[0020] Figure 2 This is a surface view of the Sn-Al-Cu phase change thermal storage microcapsule prepared in this invention with a rise time of 150 μs.

[0021] Figure 3 The image shows the cross-sectional SEM morphology of the Sn-Al-Cu phase change thermal storage microcapsule prepared in this invention with a rise time of 150 μs.

[0022] Figure 4 This is a surface view of the Sn-Al-Cu phase change thermal storage microcapsule prepared in this invention with a rise time of 100 μs.

[0023] Figure 5 This is a cross-sectional SEM image of the Sn-Al-Cu phase change thermal storage microcapsule prepared in this invention with a rise time of 100 μs.

[0024] In the diagram: 1. Piezoelectric ceramic; 2. Drive rod; 3. Infrared thermometer; 4. Ceramic plate; 5. Micropore; 6. Molecular pump; 7. Mechanical pump; 8. Droplet; 9. Core-shell structured particle; 10. Particle collector; 11. Fall tube; 12. Vacuum chamber; 13. Pre-collection tray; 14. High-speed camera; 15. Crucible; 16. Heating coil; 17. Differential pressure controller; 18. Computer; 19. Crucible inlet pipe; 20. Signal generator; 21. Alloy melt. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0029] Example 1 This invention provides a preparation apparatus for monodisperse reversible core-shell phase change thermal storage microcapsules, which is used to prepare monodisperse reversible core-shell phase change thermal storage microcapsules. The apparatus includes a piezoelectric ceramic 1, a transmission rod 2, an infrared thermometer 3, a ceramic sheet 4, a molecular pump 6, a mechanical pump 7, a particle collector 10, a drop tube 11, a vacuum chamber 12, a pre-collection disk 13, a high-speed camera 14, a crucible 15, a heating coil 16, a differential pressure controller 17, a computer 18, a crucible inlet pipe 19, and a signal generator 20.

[0030] Heating coil 16 is disposed on the outer wall of crucible 15, which is disposed above the interior of vacuum chamber 12. Transmission rod 2 is inserted into alloy melt 21 inside crucible 15 through the top of vacuum chamber 12. Transmission rod 2 extends out of the upper end of vacuum chamber 12 and is connected to piezoelectric ceramic 1. Ceramic sheet 4 is disposed at the bottom of crucible 15. A through hole is opened at the center of the bottom of crucible 15. A micro hole 5 is opened at the center of ceramic sheet 4. The micro hole 5 communicates with the inner cavity and through hole of crucible 15.

[0031] The pre-collection plate 13 is installed inside the vacuum chamber 12 on one side. The bottom of the vacuum chamber 12 is connected to the drop tube 11, and the bottom of the drop tube 11 is connected to the particle collector 10. The drop tube 11 is located directly below the micropore 5.

[0032] The piezoelectric ceramic 1 is connected to the signal generator 20, which is electrically connected to the computer 18. The computer 18 is electrically connected to a differential pressure controller 17, which is connected to one end of the crucible inlet pipe 19. The other end of the crucible inlet pipe 19 is inserted into the crucible 15 through the side wall of the vacuum chamber 12. The computer 18 is also electrically connected to a high-speed camera 14, which is installed on one side wall of the vacuum chamber 12. The infrared thermometer 3 is installed on the other side wall of the vacuum chamber 12. The mechanical pump 7 is connected to the molecular pump 6, which is connected to the vacuum chamber 12.

[0033] Example 2 A method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules includes the following steps: Step 1: Loading and Vacuuming: After cleaning and drying, the metal raw materials are weighed and mixed according to the set proportions, and then loaded into a crucible 15 equipped with micropores 5. A heating coil 16 is installed around the crucible 15. When using the equipment, the mechanical pump 7 is first started to pre-evacuate the system, reducing the pressure in the vacuum chamber 12 to below 4 Pa; then, the molecular pump 6 is turned on to further extract the gas, bringing the system to a high vacuum state with a vacuum degree better than 4 × 10⁻⁶ Pa. -3Pa. After the set vacuum conditions are reached, the mechanical pump 7 is turned off, and high-purity inert gas is slowly introduced into the vacuum chamber 12 through the crucible inlet pipe 19 until the system pressure returns to atmospheric pressure, so as to create a stable, low-oxygen atmosphere.

[0034] Step 2, Melt Processing: After opening the pre-collection tray 13, connect the infrared thermometer 3. Heat the metal raw materials in the crucible 15 by adjusting the input current of the heating coil 16, ensuring the heating temperature is 10-80°C higher than the alloy liquidus temperature. Melt the mixed metal raw materials and hold at this temperature for 20 minutes to promote complete melting and homogenization of the composition. The resulting alloy melt 21 is obtained. During heating, the melt state is determined by gradually adjusting the position of the transmission rod 2. Once the metal raw materials are confirmed to be completely melted, adjust the system temperature to the target temperature and continue holding for 20 minutes to ensure a stable and uniform temperature field distribution within the alloy melt 21. Additionally, the transmission rod 2 can be appropriately immersed in the alloy melt 21 for synchronous heating to reduce disturbances to the local temperature field. Simultaneously, inert gas is introduced into the crucible 15 through the crucible inlet pipe 19, creating a pressure difference of 1-4 Torr between the inside of the crucible 15 and the vacuum chamber 12.

[0035] Step 3: Turn on the signal generator 20 and set the pulse drive signal. Under the condition of adjusting the rise time parameter of the pulse drive signal, the output electrical signal is applied to the piezoelectric ceramic 1, causing it to vibrate periodically with different response characteristics. This further drives the transmission rod 2 to reciprocate. The transmission rod 2 acts on the alloy melt 21 at the bottom of the crucible 15, causing the liquid to be ejected from the micropore 5, forming droplets 8. As the rise time parameter changes, the disturbance intensity of the alloy melt 21 and the ejection state of the droplets 8 change accordingly, thereby controlling the formation and solidification behavior of the droplets. During the process, the computer 18 monitors and dynamically adjusts the output voltage waveform in real time to ensure the stability of the droplet 8 ejection process. Simultaneously, a high-speed camera 14 captures and records the formation, contraction, and cooling solidification process of the droplets 8 in real time. During rapid cooling, the ejected droplets 8 first form incompletely solidified phase-separated particles, and then further solidify without a container during free fall, ultimately forming core-shell structured microparticles 9.

[0036] Step 4, Particle Collection: The ejected droplets 8 cool and solidify within the inert gas-filled dropper 11, eventually settling into the bottom particle collector 10. The particle collector 10 has multiple independent collection areas. By changing the rise time parameter, core-shell structured microparticles 9 obtained under different conditions are collected and classified for preservation, thereby improving the specificity of sample analysis and the comparability of results. After particle preparation, the piezoelectric ceramic 1, infrared thermometer 3, and heating coil 16 are sequentially turned off. After the device cools to room temperature, inert gas is introduced into the vacuum chamber 12 to restore it to atmospheric pressure. The particle collector 10 is then opened to collect the prepared core-shell structured particles 9. The device is then re-evacuated for the next preparation. The core-shell structured particles 9 are monodisperse reversible core-shell phase change thermal storage microcapsules, consisting of an outer shell and a core disposed inside the outer shell. The outer shell is a high-melting-point alloy, and the core is a low-melting-point alloy.

[0037] In the droplet jetting process of monodisperse core-shell phase change thermal storage microparticles, the driving system has a significant impact on droplet formation stability and jetting quality. This invention, based on the principle of pulsed micro-orifice jetting, proposes a method to regulate droplet jetting behavior by adjusting the rise time parameter of the pulse driving signal. This method can alter the dynamic response characteristics of piezoelectric ceramics in an extremely short time, thereby precisely controlling the disturbance intensity and energy transfer process of the drive rod on the alloy melt, achieving stable regulation of droplet formation, liquid column fracture, and rapid solidification behavior.

[0038] Compared with traditional droplet ejection methods, this invention has advantages such as simple structure, fast response speed, high ejection stability, and high precision in parameter control. By adjusting the rise time parameter, the droplet size uniformity, sphericity, and ejection continuity can be effectively improved, and the liquid-liquid phase separation, second-phase migration, and core-shell structure evolution processes within the droplet can be further affected, thereby achieving the controllable preparation of inverted core-shell structured microparticles.

[0039] Furthermore, the microparticles prepared by this invention have the characteristics of uniform particle size, high sphericity, complete core-shell structure and good thermal stability, which can meet the needs of continuous, stable and large-scale industrial preparation, and have broad application prospects in the fields of phase change thermal storage, electronic thermal management and core-shell composite functional materials.

[0040] Example 3 In this embodiment, the metal raw materials are Sn, Al, and Cu. The Sn-Al-Cu phase change thermal storage microcapsules are prepared using the preparation method of Example 2. The Al-Cu-rich phase forms the shell, and the Sn-rich phase forms the core.

[0041] like Figures 2-5 The image shows the surface and cross-sectional SEM morphology of Sn-Al-Cu phase change thermal storage microcapsules under different rise time parameters. Figure 2 and Figure 3 This is a schematic diagram of the surface and a cross-sectional SEM image of the Sn-Al-Cu phase change thermal storage microcapsule with a rise time of 150 μs. Figure 4 and Figure 5 The images show the surface and cross-sectional SEM morphology of the Sn-Al-Cu phase change thermal storage microcapsule when the rise time is 100 μs.

[0042] When the rise time is 100µs, the deviation between the drive rod movement and the input waveform increases, causing the droplet to oscillate more during its descent. This generates strong convection within the droplet, significantly increasing the collision probability of Al-Cu-rich phase droplets in the matrix, leading to rapid growth of these droplets. Simultaneously, the alternating shifts between the equator and polar axis compress the Al-Cu-rich phase to the outer layer of the droplet, such as... Figure 5 Simultaneously, due to the Marangoni motion of the Al-Cu phase droplets and their short rise edge causing rapid droplet descent, the cooling rate of the droplets accelerates. This results in the droplets solidifying before the Al-Cu phase has sufficient time to migrate, thus highlighting the Sn-rich phase matrix and forming a nucleus. Figure 3 The core-shell structure particles with completely opposite core-shell colors are used to obtain the inverse core-shell structure particles of this invention, which have a high melting point shell and a low melting point core.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A monodisperse reversible core-shell structured phase change thermal storage microcapsule, characterized in that, It includes: an outer shell and a core disposed inside the outer shell, wherein the outer shell is a high-melting-point alloy and the core is a low-melting-point alloy.

2. An apparatus for preparing monodisperse reversible core-shell phase change thermal storage microcapsules, used to prepare the monodisperse reversible core-shell phase change thermal storage microcapsules as described in claim 1, characterized in that, include: Piezoelectric ceramic (1), transmission rod (2), infrared thermometer (3), ceramic plate (4), molecular pump (6), mechanical pump (7), particle collector (10), drop tube (11), vacuum chamber (12), pre-collection plate (13), high-speed camera (14), crucible (15), heating coil (16), differential pressure controller (17), computer (18), crucible inlet pipe (19), and signal generator (20); The heating coil (16) is disposed on the outer wall of the crucible (15), the crucible (15) is disposed above the interior of the vacuum chamber (12), the transmission rod (2) is inserted into the alloy melt (21) inside the crucible (15) through the top of the vacuum chamber (12), the transmission rod (2) extends out of the upper end of the vacuum chamber (12) and is connected to the piezoelectric ceramic (1), the ceramic plate (4) is disposed at the bottom of the interior of the crucible (15), the bottom center of the crucible (15) has a through hole, the center of the ceramic plate (4) has a micro hole (5), the micro hole (5) is connected to the inner cavity and the through hole of the crucible (15); The pre-collection disk (13) is installed on one side inside the vacuum chamber (12). The bottom of the vacuum chamber (12) is connected to the drop tube (11). The bottom of the drop tube (11) is connected to the particle collector (10). The drop tube (11) is located directly below the micropore (5). The piezoelectric ceramic (1) is connected to the signal generator (20), the signal generator (20) is electrically connected to the computer (18), the computer (18) is electrically connected to the differential pressure controller (17), the differential pressure controller (17) is connected to one end of the crucible inlet pipe (19), and the other end of the crucible inlet pipe (19) is inserted into the crucible (15) through the side wall of the vacuum chamber (12); the computer (18) is also electrically connected to the high-speed camera (14), the high-speed camera (14) is installed on one side wall of the vacuum chamber (12); the infrared thermometer (3) is installed on the other side wall of the vacuum chamber (12), the mechanical pump (7) is connected to the molecular pump (6), and the molecular pump (6) is connected to the vacuum chamber (12).

3. A method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules, using the preparation apparatus as described in claim 2, characterized in that, Includes the following steps: Step 1, Loading and Vacuuming: After cleaning and drying the metal raw materials, weigh and mix them according to the set composition ratio and load them into the crucible (15). A heating coil (16) is set around the crucible (15). When using the equipment, first start the mechanical pump (7) to pre-evacuate the vacuum chamber (12) and the crucible (15), and then turn on the molecular pump (6) to further extract gas from the vacuum chamber (12) and the crucible (15) to achieve a high vacuum state. After the set vacuum conditions are reached, turn off the mechanical pump (7) and slowly fill the vacuum chamber (12) with high-purity inert gas through the crucible gas inlet pipe (19) until the system pressure returns to the normal pressure level to create a stable, low-oxygen atmosphere. Step 2, Melt processing: After turning on the pre-collection tray (13), turn on the infrared thermometer (3), and heat the metal raw materials in the crucible (15) by adjusting the input current of the heating coil (16). Heat the mixed metal raw materials to melt and keep them at a constant temperature for 20 minutes to promote the full melting of the metal raw materials and achieve uniform composition. After melting, the alloy melt (21) is obtained. During the heating process, the state of the melt is judged by gradually adjusting the position of the transmission rod (2). When it is confirmed that the metal raw materials have been completely melted, the system temperature is adjusted to the target temperature and kept at a constant temperature for 20 minutes to ensure that the temperature field distribution inside the alloy melt (21) is stable and uniform. In addition, the transmission rod (2) is appropriately immersed in the alloy melt (21) for synchronous heating to reduce the disturbance to the local temperature field. At the same time, inert gas is introduced into the crucible (15) through the crucible gas inlet pipe (19) to form a pressure difference of 1~4 Torr between the inside of the crucible (15) and the vacuum chamber (12). Step 3: Turn on the signal generator (20) and set the pulse drive signal; under the condition of adjusting the rise time parameter of the pulse drive signal, the output electrical signal is applied to the piezoelectric ceramic (1) to generate periodic vibrations with different response characteristics, and further drive the transmission rod (2) to reciprocate; the alloy melt (21) at the bottom of the crucible (15) is acted on by the transmission rod (2), so that the liquid is ejected from the micropore (5) to form droplets (8); with the change of the rise time parameter, the disturbance intensity of the alloy melt (21) and the ejection pattern of the droplets (8) are affected. The state changes accordingly, thereby controlling the formation and solidification behavior of the droplets; during the process, the computer (18) is used to monitor and dynamically adjust the output voltage waveform in real time to ensure the stability of the droplet (8) ejection process. At the same time, a high-speed camera (14) is used to capture and record the formation, contraction and cooling solidification process of the droplets (8) in real time; the droplets (8) formed by ejection first form incompletely solidified phase-separated particles during rapid cooling, and further complete containerless solidification during free fall, finally forming core-shell structured particles (9). Step 4, Particle Collection: The droplets (8) formed by the jet are cooled and solidified in the inert gas-filled drop tube (11) and finally settle into the bottom particle collector (10). The particle collector (10) is equipped with multiple independent collection areas. During the process, by changing the rise time parameter, the core-shell structure microparticles (9) obtained under different conditions are collected and classified for preservation, thereby improving the specificity of sample analysis and the comparability of results. After the particle preparation is completed, the piezoelectric ceramic (1), infrared thermometer (3) and heating coil (16) are turned off in sequence. After the device cools to room temperature, inert gas is introduced into the vacuum chamber (12) to restore it to normal pressure. The particle collector (10) is turned on to collect the prepared core-shell structure particles (9). Then the device is evacuated again for the next preparation.

4. The method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules according to claim 3, characterized in that, In step 1, after pre-evacuation, the pressure in the vacuum chamber (12) drops to below 4 Pa; under high vacuum conditions, the vacuum level is below 4 × 10⁻⁶ Pa. -3 Pa.

5. The method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules according to claim 3, characterized in that, In step 2, when heating the metal raw material, the heating temperature is 10 to 80°C higher than the alloy liquidus temperature.

6. The method for preparing monodisperse reversible core-shell structured phase change thermal storage microcapsules according to claim 3, characterized in that, In step 4, the rise time is 100μs.

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