A complex gel phase change heat storage structure and a preparation method thereof

Abstract

The application provides a complex gel phase change heat storage structure and a preparation method thereof, and relates to the technical field of energy storage materials.The method comprises the following steps: obtaining a hydrogel packaging model, then filling a PVA aqueous solution containing a hydrated inorganic salt into the packaging model by vacuum pumping, then freeze-thaw molding, and finally performing secondary packaging on the surface of the packaging model by using a high-thermal-conductivity elastomer.The application enables the hydrogel to have a complex structure, thereby adapting to complex application scenarios, and the hydrogel is double-packaged by using the packaging model and the high-thermal-conductivity elastomer, so that the hydrogel has excellent leakage prevention performance.In addition, the content of the hydrogel in the packaging model can be indirectly controlled by adjusting the filling rate of the packaging model.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage materials, and particularly relates to a complex gel phase change heat storage structure and a preparation method thereof. BACKGROUND

[0002] With the rapid development of human society, the problem of over-consumption of traditional fossil energy such as oil, natural gas and coal has occurred. These energy sources are limited and non-renewable, and overuse and waste of energy will inevitably lead to environmental pollution and climate warming. However, in many fields such as industry and livelihood, there is often a problem of low use efficiency in the process of energy conversion and utilization, which needs to be solved urgently. In recent years, energy storage technology has developed rapidly, providing an effective way to improve energy utilization.

[0003] A hydrogel is a material with a very high water content and can exhibit a solid state at room temperature. The water inside can evaporate freely, so when the surface temperature of an object rises, the hydrogel can greatly reduce the surface temperature of the object, and is an excellent energy storage material.

[0004] However, a general hydrogel will continue to lose water and must be soaked in liquid water to restore its original state and then work normally. In addition, it is difficult to form a complex three-dimensional structure, so it is difficult to adapt to complex environmental conditions. SUMMARY

[0005] To solve the above problems, the present application provides a complex gel phase change heat storage structure and a preparation method thereof. The method enables the hydrogel to have a complex structure and excellent leak-proof performance, so that it can adapt to complex application scenarios and be used on the surface of various heat source objects.

[0006] To achieve the above purposes, the technical solutions adopted by the present application are as follows:

[0007] In a first aspect, the present application provides a complex gel phase change heat storage structure preparation method, comprising the following steps:

[0008] Providing an encapsulation model;

[0009] Filling a PVA aqueous solution containing a hydrated inorganic salt into the encapsulation model by vacuum pumping to perform first encapsulation;

[0010] Freezing and forming the encapsulation model after the first encapsulation to form a PVA hydrogel;

[0011] Filling a high-thermal-conductivity elastomer into the surface of the encapsulation model after the PVA hydrogel is formed to perform second encapsulation;

[0012] After waiting for the high-thermal-conductivity elastomer to completely solidify, a complex gel phase change heat storage structure is obtained.

[0013] As a further improvement of the application, the packaging model is printed by 3D printing to set the shape of the heat storage structure, and the filling rate of the packaging model is 18-22%.

[0014] As a further improvement of the application, the material of the packaging model is a printing material doped with a high-thermal-conductivity material, and the printing material is one or more of PLA, ABS, and nylon; and the high-thermal-conductivity material is one or more of carbon nanotubes, carbon fibers, and graphene.

[0015] As a further improvement of the application, the mass fraction of PVA in the PVA aqueous solution is 5-20%.

[0016] As a further improvement of the application, the hydrated inorganic salt includes one or more of sodium sulfate decahydrate, calcium chloride hexahydrate, and disodium hydrogen sulfate dodecahydrate, and the amount of the hydrated inorganic salt added is the same as that of PVA.

[0017] As a further improvement of the application, the freeze-thaw molding of the packaging model after the first packaging includes:

[0018] The packaging model after the first packaging is frozen at -18-25℃ for 8-12 h, thawed at 20-26℃ for 1-3 h, and the freezing and thawing operation is cycled 3-7 times until the PVA hydrogel is formed.

[0019] As a further improvement of the application, the high-thermal-conductivity elastomer is silicone rubber doped with a high-thermal-conductivity material, and the high-thermal-conductivity material is one or more of metal particles, liquid metal, carbon nanotubes, carbon fibers, and graphene.

[0020] As a further improvement of the application, the filling of the high-thermal-conductivity elastomer to the surface of the packaging model after the PVA hydrogel is formed includes:

[0021] The silicone rubber and the high-thermal-conductivity material are mixed to form the high-thermal-conductivity elastomer, and the packaging model containing the PVA hydrogel is immersed in the high-thermal-conductivity elastomer before the high-thermal-conductivity elastomer is solidified, so as to form a high-thermal-conductivity elastomer encapsulation layer on the surface of the packaging model.

[0022] As a further improvement of the application, the filling rate of the packaging model is variable, the wall thickness of the packaging model is less than 1 mm, and the thickness of the high-thermal-conductivity elastomer encapsulation layer is less than 1 mm.

[0023] In a second aspect, the application provides a complex gel phase change heat storage structure prepared according to the preparation method of the complex gel phase change heat storage structure.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The application provides a preparation method of a complex gel phase change heat storage structure, a hydrogel packaging model is obtained through 3D printing, then a PVA aqueous solution containing hydrated inorganic salt is filled into the packaging model through vacuum pumping, then the packaging model is freeze-molded, and finally the surface of the packaging model is secondarily packaged by using a high-thermal-conductivity elastomer. The application enables the hydrogel to have a complex structure, thereby adapting to complex application scenarios, and the hydrogel is doubly packaged by using the packaging model and the high-thermal-conductivity elastomer, so that the hydrogel has excellent leakage prevention performance. In addition, the content of the hydrogel in the packaging model can be indirectly controlled by adjusting the filling rate of the packaging model. The preparation method can prepare a phase change heat storage hydrogel with a complex three-dimensional structure, and the preparation steps are simple and easy to implement. The complex gel phase change heat storage structure is packaged by the packaging model and the high-thermal-conductivity elastomer, and can adapt to various harsh and complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of a preparation method of a complex gel phase change heat storage structure.

[0027] Figure 2 It is a complex gel phase change heat storage device prepared by using Figure 1 a preparation method.

[0028] Figure 3 It is a complex gel phase change heat storage device prepared by using Figure 2 a preparation method. Figure 1 ; (a) is a top view, and (b) is a section view along A-A direction.

[0029] Figure 4 It is a complex gel phase change heat storage device prepared by using Figure 2 a preparation method. Figure 2 ; (a) is a top view, and (b) is a section view along B-B direction.

[0030] Figure 5 It is a graph for verifying the temperature control performance change trend of the complex gel phase change heat storage structure. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0032] In the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0033] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0034] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. 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 this application.

[0035] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0036] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0037] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0038] The first aspect of this application provides a method for preparing a complex gel phase change thermal storage structure, comprising the following steps:

[0039] S1 provides the encapsulation model;

[0040] S2, A PVA aqueous solution containing hydrated inorganic salts is filled into the encapsulation model by vacuuming to perform the first encapsulation;

[0041] S3, freeze-thaw molding is performed on the encapsulation model after the first encapsulation to form a PVA hydrogel;

[0042] S4, the high-thermal-conductivity elastomer is filled into the surface of the encapsulation model after the PVA hydrogel is formed, and secondary encapsulation is performed;

[0043] The first aspect of the present application provides a preparation method of a complex gel phase change heat storage structure. The preparation method first prepares an encapsulation model. The 3D printing technology can be used to obtain an encapsulation model with a corresponding shape according to a preset heat storage structure complex model. This step ensures that the encapsulation model has the required accuracy and complexity, providing a basis for subsequent hydrogel filling and encapsulation. Then, the PVA aqueous solution is prepared and filled. PVA (polyvinyl alcohol) is dissolved in water to prepare a PVA aqueous solution containing a certain concentration of hydrated inorganic salt. The addition of hydrated inorganic salt can improve the heat storage performance and thermal stability of the hydrogel. The PVA aqueous solution containing hydrated inorganic salt is filled into the encapsulation model by vacuum pumping. Vacuum pumping can remove gas and water vapor in the solution to avoid the generation of bubbles and ensure the uniformity and integrity of the filling. Thirdly, freeze-thaw molding of the hydrogel is performed. The encapsulation model filled with the PVA aqueous solution is subjected to freezing treatment to form ice crystals from the water molecules in the solution, thereby realizing the preliminary solidification of the hydrogel. Subsequently, thawing treatment is performed to melt and rearrange the ice crystals to form a hydrogel with a stable three-dimensional network structure. This process ensures that the hydrogel has excellent mechanical properties and heat storage performance. Finally, the high-thermal-conductivity elastomer is subjected to secondary encapsulation to prepare a high-thermal-conductivity elastomer material. The material should have good thermal conductivity and elasticity to ensure that the encapsulated gel phase change heat storage structure can maintain stable performance in various environments. The high-thermal-conductivity elastomer material is uniformly coated on the surface of the encapsulation model for secondary encapsulation. This step not only improves the overall strength of the structure, but also ensures that heat can be efficiently transferred to the external environment.

[0044] In step S1, an encapsulation model is provided. In one specific embodiment, a 3D printing method is used to print an encapsulation model with a specific heat storage structure shape. The specific shape can be designed according to specific requirements, and the present application does not make specific limitations.

[0045] More specifically, the complex gel phase change heat storage structure includes an encapsulation model, a hydrogel, and a high-thermal-conductivity elastomer. The encapsulation model is obtained by 3D printing. Then, the PVA aqueous solution containing hydrated inorganic salt is filled into the encapsulation model by vacuum pumping to encapsulate the hydrogel for the first time. Subsequently, the PVA aqueous solution containing hydrated inorganic salt is subjected to freeze-thaw molding. Finally, the surface of the encapsulation model is subjected to secondary encapsulation using a high-thermal-conductivity elastomer.

[0046] In some embodiments, the packaging model of the present application can be a basic structure corresponding to a specific application, such as a heat storage element, etc., which has a complex shape. Figures 2 to 4

[0047] In some embodiments, the material of the packaging model is a printing material doped with high thermal conductivity material, and the printing material is one or more of PLA, ABS, and nylon; and the high thermal conductivity material is one or more of carbon nanotubes, carbon fibers, and graphene.

[0048] PLA is derived from renewable resources such as corn starch and has biodegradability, meeting environmental protection requirements. The printing process is smooth and suitable for use in home and educational environments. ABS material has good impact strength and is suitable for printing workpieces with high strength requirements. It has good heat resistance and can maintain stable performance within a certain temperature range. Nylon material has high strength and toughness and is suitable for printing precision parts of industrial and aerospace levels. It has excellent wear resistance and is suitable for packaging models that require wear resistance.

[0049] As an example, carbon nanotubes have excellent thermal conductivity and can significantly improve the thermal conductivity of the packaging model. Carbon nanotubes can also enhance the mechanical properties of the packaging model to some extent. Carbon fibers are light in weight and high in strength, and are suitable for packaging models that require lightweight and high strength. By adjusting the content and arrangement of carbon fibers, the thermal conductivity of the packaging model can be controlled. Graphene also has excellent thermal conductivity and can further improve the thermal efficiency of the packaging model. The synergistic effect of graphene and other thermal conductive materials (such as carbon nanotubes and carbon fibers) can significantly reduce the interfacial thermal resistance and improve the overall thermal conductivity.

[0050] In some embodiments, through 3D printing technology, the packaging model can be customized according to actual needs, meeting the needs of individualization and customization. The printing material doped with high thermal conductivity material can significantly improve the heat dissipation efficiency of the packaging model, and is suitable for electronic devices, industrial equipment, etc. that require high-efficiency heat dissipation. 3D printing technology can achieve rapid and accurate manufacturing, reduce manufacturing costs, and improve production efficiency. The selection of printing materials such as PLA, ABS, and nylon is diverse, and appropriate materials can be selected according to specific application scenarios, and the addition of high thermal conductivity materials further enriches the performance and application range of the packaging model. The use of PLA, ABS, and nylon printing materials doped with high thermal conductivity materials to make packaging models has many advantages, including material characteristics, high thermal conductivity materials, and comprehensive advantages. These advantages make the packaging model have wide application prospects in the fields of electronic devices, industrial equipment, etc.

[0051] In addition, 3D printing technology can accurately manufacture packaging models with complex shapes and structures, providing great flexibility and accuracy for the preparation of gel phase change heat storage structures. ​

[0052] In step S2, the PVA aqueous solution containing the hydrated inorganic salt is filled into the packaging mold by vacuum suction to perform the first packaging; the mass fraction of PVA in the PVA aqueous solution is 5% - 20%.

[0053] For example, the PVA aqueous solution is filled into the packaging mold under vacuum suction to avoid the generation of bubbles and ensure the uniformity and integrity of the filling. The freeze-thaw molding process makes water molecules form ice crystals and rearrange to form a stable three-dimensional network structure, which endows the hydrogel with excellent mechanical properties and heat storage performance.

[0054] In some embodiments, the mass fraction of PVA is selected from 5% - 10%, 15% - 20%, 10% - 15%, 7% - 14%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%.

[0055] For example, the hydrated inorganic salt includes one or more of sodium sulfate decahydrate, calcium chloride hexahydrate, and disodium hydrogen sulfate dodecahydrate. These hydrated inorganic salts generally have good solubility and can be uniformly dissolved in the PVA aqueous solution to form a stable solution system. Some hydrated inorganic salts (such as sodium sulfate decahydrate) have strong hygroscopicity, which helps to adjust the humidity inside the packaging mold and maintain the stability of the environment. These hydrated inorganic salts will lose crystal water during heating, but generally will not decompose or produce harmful substances, ensuring the safety of the packaging process. The addition of hydrated inorganic salts can form interactions with PVA molecules, enhancing the mechanical strength of the packaging material and making it more robust and durable. Some hydrated inorganic salts (such as calcium chloride hexahydrate) can form more stable inorganic skeletons after losing crystal water, improving the heat resistance of the packaging material. The hygroscopicity of hydrated inorganic salts helps to adjust the humidity inside the packaging mold, preventing performance degradation or damage due to excessive or insufficient humidity. Some hydrated inorganic salts (such as disodium hydrogen sulfate dodecahydrate) can act as pH regulators to maintain the pH value inside the packaging mold within an appropriate range, ensuring the stability and performance of the packaging material. The addition of hydrated inorganic salts can improve the flowability of the PVA aqueous solution, making it easier to fill into the packaging mold by vacuum suction, improving the filling efficiency and packaging quality. The addition of hydrated inorganic salts can also reduce the generation of bubbles and defects during the packaging process, improving the integrity and reliability of the packaging mold.

[0056] Exemplarily, the phase change principle of the complex gel phase change heat storage structure described above is mainly based on the latent heat characteristics of the phase change energy storage material (PCM). The phase change energy storage material can absorb or release a large amount of heat during the phase change process, and the temperature remains almost unchanged. This characteristic makes PCM an effective thermal control material. During the phase change process, PCM stores or releases heat by changing its physical state (such as solid to liquid or liquid to solid).

[0057] In step S3, the encapsulation model after the first encapsulation is freeze-thaw formed to form a PVA hydrogel; including: freezing the encapsulation model after the first encapsulation at-20℃ for 10h, thawing at 25℃ for 2h, and repeating the freezing and thawing operation for 3-7 times, until the PVA hydrogel is formed.

[0058] In the above scheme, in step S3, the encapsulation model after the first encapsulation is freeze-thaw formed to form a PVA (polyvinyl alcohol) hydrogel. The process is mainly based on the physical crosslinking characteristics of polyvinyl alcohol and its structural changes during the freeze-thaw process. The formation of polyvinyl alcohol hydrogel mainly depends on the physical crosslinking between its molecular chains. During the freezing process, water gradually solidifies into ice crystals, and the formation of these ice crystals helps to "compress" and arrange the polyvinyl alcohol molecular chains more orderly. When thawing, the ice crystals melt, but the interaction between the polyvinyl alcohol molecular chains has been strengthened, thereby forming a stable hydrogel structure. Through multiple freeze-thaw cycles, the interaction between the polyvinyl alcohol molecular chains is further strengthened, forming a more dense and stable hydrogel network structure. This structural change makes the PVA hydrogel have better mechanical strength and stability.

[0059] Further, by using the above means, after multiple freeze-thaw cycles, more physical crosslinking points are formed between the molecular chains of the PVA hydrogel, thereby improving its mechanical strength. This makes the PVA hydrogel able to withstand greater external forces in practical applications, and not easy to break or deform. Maintaining biocompatibility: polyvinyl alcohol is a hydrophilic polymer with good biocompatibility. The PVA hydrogel formed by physical crosslinking does not introduce any harmful chemicals, so its original biocompatibility is maintained. This makes the PVA hydrogel have wide application prospects in the biomedical field, such as being used as a tissue engineering material, a drug release carrier, etc.

[0060] Further, the present application can realize the precise control of the structure of PVA hydrogel by adjusting the number of freeze-thaw cycles, the temperature and time of freezing and thawing, and other parameters. This controllable forming process enables PVA hydrogel to meet the requirements of different application fields for material performance. Compared with the traditional chemical crosslinking method, the physical crosslinking method does not need to introduce any chemical crosslinking agent or catalyst, thereby simplifying the preparation process and reducing the production cost. Therefore, the process of forming PVA hydrogel by performing multiple freeze-thaw cycles on the packaging model after the first packaging has the advantages of improving mechanical strength, maintaining biocompatibility, controllable forming process, and simplifying the preparation process.

[0061] In some embodiments, the number of cycles is determined according to the formation of the hydrogel, and can be 3-7 times, for example, 3 times, 4 times, 5 times, 6 times, or 7 times.

[0062] In step S4, the high-thermal-conductivity elastomer is filled into the surface of the packaging model after the PVA hydrogel is formed, and secondary packaging is performed, including: mixing the silicone rubber and the high-thermal-conductivity material to form the high-thermal-conductivity elastomer; and immersing the packaging model containing the PVA hydrogel into the high-thermal-conductivity elastomer before the high-thermal-conductivity elastomer is solidified, to form a high-thermal-conductivity elastomer packaging layer on the surface of the packaging model.

[0063] For example, the high-thermal-conductivity elastomer material has good thermal conductivity and elasticity, can ensure that heat is efficiently transferred to the external environment, and maintains the overall strength of the structure. The secondary packaging process not only improves the stability of the structure, but also enhances the reliability and durability of the structure in actual application.

[0064] In some embodiments, the high-thermal-conductivity elastomer is silicone rubber doped with high-thermal-conductivity material, and the high-thermal-conductivity material is one or more of metal particles, liquid metal, carbon nanotubes, carbon fibers, and graphene.

[0065] In some embodiments, the filling rate of the packaging model is variable, the wall thickness of the packaging model is less than 1 mm, and the thickness of the high-thermal-conductivity elastomer packaging layer is less than 1 mm.

[0066] In the present application, since the phase change energy storage material is a functional material with high energy storage and high energy saving, the hydrated salt is one of inorganic phase change energy storage materials with large energy storage density and high thermal conductivity, which stores and releases energy through heat absorption and heat release during melting and crystallization. The combination of the phase change energy storage material and the hydrogel can form a phase change heat storage hydrogel, which can be used as the basis for the application of phase change devices.

[0067] The phase change principle of the complex gel phase change heat storage structure is as follows: the hydrogel is the main phase change energy storage material (PCM). When the hydrogel is heated, the water molecules inside it begin to vibrate and absorb heat. As the temperature rises, the hydrogen bonds between the water molecules gradually break, causing the hydrogel to change from a solid state to a liquid state (or a liquid-like state), and in the process, a large amount of heat is absorbed. Conversely, when the hydrogel cools down, the liquid water molecules re-form hydrogen bonds and change to a solid state, releasing the heat absorbed earlier.

[0068] Further, the addition of hydrated inorganic salts can affect the phase change temperature and latent heat value of the hydrogel. By adjusting the type and concentration of the hydrated inorganic salts, the phase change characteristics of the hydrogel can be customized to meet specific application requirements. Hydrated inorganic salts can also enhance the thermal stability and mechanical properties of the hydrogel, allowing it to maintain structural integrity during the phase change process.

[0069] Further, the high thermal conductivity elastomer as a secondary packaging material has excellent thermal conductivity. It can efficiently transfer the heat absorbed or released by the hydrogel during the phase change process to the external environment. The elastic properties of the high thermal conductivity elastomer can also ensure the stability and durability of the packaging structure under thermal stress.

[0070] Therefore, the phase change principle of the complex gel phase change heat storage structure is based on the latent heat characteristics of PCM and the interaction of hydrogel, hydrated inorganic salts and high thermal conductivity elastomer. The structure stores and releases heat by precisely controlling the phase change process, thereby achieving effective management and control of temperature.

[0071] The second object of the present application is to provide a complex gel phase change heat storage structure prepared according to the complex gel phase change heat storage structure preparation method described above.

[0072] In the application of the complex gel phase change heat storage structure, when a liquid with a higher temperature flows through it, it will absorb part of the heat in the liquid for storage. The specific principle of this process involves the latent heat characteristics of the phase change energy storage material and the heat conduction and phase change mechanism of the hydrogel. The phase change energy storage material can absorb or release a large amount of heat during the phase change process, while the temperature remains almost unchanged. This is the latent heat characteristic of PCM, which is the basis for its use as a thermal control material. In the above scheme, the hydrogel is the main PCM, which will undergo a phase change from a solid state to a liquid state (or a liquid-like state) when heated, and in the process, it will absorb heat.

[0073] The hydrogel has excellent heat conduction performance and can effectively transfer heat from high-temperature areas to low-temperature areas. When a liquid with high temperature flows through, the hydrogel quickly absorbs the heat in the liquid and transfers the heat to the entire gel structure through its internal heat conduction mechanism. With the transfer and accumulation of heat, some areas in the hydrogel reach its phase transition temperature. At this time, the hydrogel undergoes a phase transition from solid to liquid (or liquid-like) and absorbs a large amount of heat in the process. This phase transition process enables the hydrogel to effectively store heat from the high-temperature liquid.

[0074] In some embodiments, when the hydrogel absorbs enough heat and undergoes a phase transition, it stores a large amount of thermal energy inside. These thermal energies can be released when needed through appropriate conditions such as lowering the ambient temperature or applying external pressure, thereby achieving the functions of heat storage and release. In the complex gel phase change heat storage structure, when a liquid with high temperature flows through, it will use the heat conduction and phase change mechanism of the hydrogel to absorb the heat in the liquid and store it. This process, based on the latent heat characteristics of PCM and the unique properties of hydrogel, achieves effective management and control of heat.

[0075] The following will be described in conjunction with specific embodiments.

[0076] Embodiment 1

[0077] The present embodiment provides a preparation method of a complex gel phase change heat storage structure, which is obtained by 3D printing Figure 1 The encapsulation model is shown in FIG. 1, and then a PVA aqueous solution containing hydrated inorganic salt is filled into the encapsulation model by vacuum pumping, followed by freeze-thaw molding, and finally the surface of the encapsulation model is encapsulated again with a high-thermal-conductivity elastomer. The above preparation process includes the following steps:

[0078] Step 1: print the encapsulation model as shown in FIG. 1 by 3D printing. In order to make the encapsulation model have enough strength, the filling rate is set to 20%, and in order to make the PVA solution more easily pumped into the encapsulation model, the wall thickness of the encapsulation model is set to 0.1 mm. The printing material is selected as PLA. Figure 1

[0079] Step 2: prepare a PVA aqueous solution with a mass fraction of 10%, and then add PVA with the same mass of sodium sulfate decahydrate and stir uniformly. Then, the PVA aqueous solution containing hydrated inorganic salt is infiltrated into the encapsulation model under the action of atmospheric pressure by vacuum pumping.

[0080] Step 3: freeze the encapsulation model containing the PVA aqueous solution with hydrated inorganic salt at -20℃ for 10 h, thaw at 25℃ for 2 h, and repeat the freezing and thawing operation for 7 cycles until the PVA hydrogel is formed. ​

[0081] Step four: mix the silicone rubber and high thermal conductive material with a stirring rod to form a high thermal conductive elastomer as the encapsulation material. Before the high thermal conductive elastomer is cured, immerse the encapsulation model containing the PVA hydrogel into the high thermal conductive elastomer, and then remove the excess high thermal conductive elastomer on the surface of the encapsulation model to make the thickness of the encapsulation high thermal conductive elastomer less than 1 mm. Wait for the high thermal conductive elastomer to be completely cured under natural conditions to form a complex gel phase change heat storage structure as shown in Figures 2 to 4 .

[0082] wherein, Figures 2 to 4 A specific complex gel phase change heat storage structure is given, which includes a phase change heat storage body 1, the phase change heat storage body 1 has an inlet 3 and an outlet 4, and the phase change heat storage body 1 has a fluid channel 2 inside, which is connected with the inlet 3 and the outlet 4.

[0083] More specifically, the fluid channel 2 is arranged in a serpentine shape in the phase change heat storage body 1 to make more uniform contact with the hydrogel.

[0084] When a liquid with a higher temperature flows through the fluid channel 2, the phase change heat storage body 1 will absorb part of the heat for heat storage.

[0085] Example 2

[0086] The embodiment provides a preparation method of a complex gel phase change heat storage structure, and the preparation process includes the following steps:

[0087] Step one: print an encapsulation model as shown in Figure 1 by using a 3D printing method. In order to make the encapsulation model have enough strength, the filling rate is set to 22%, in order to make the PVA solution more easily drawn into the encapsulation model, the wall thickness of the encapsulation model is set to 0.2 mm, and the printing material is selected as ABS.

[0088] Step two: configure a PVA aqueous solution with a mass fraction of 5%, and then add calcium chloride hexahydrate with the same mass as PVA and stir uniformly, and then the PVA aqueous solution containing the hydrated inorganic salt is infiltrated into the encapsulation model under the action of atmospheric pressure by vacuumizing.

[0089] Step three: freeze the encapsulation model containing the PVA aqueous solution with the hydrated inorganic salt at -25°C for 8h, thaw at 20°C for 3h, and repeat the freezing and thawing operation for 5 times, until the PVA hydrogel is formed.

[0090] Step four: the high thermal conductive elastomer is formed by mixing the silicone rubber and the high thermal conductive material with a stirring rod as the encapsulating material, the encapsulating model containing the PVA hydrogel is immersed in the high thermal conductive elastomer before the high thermal conductive elastomer is cured, then the excess high thermal conductive elastomer on the surface of the encapsulating model is removed, the thickness of the encapsulating high thermal conductive elastomer is less than 1 mm, and the actual thickness is 0.8 mm; and the high thermal conductive elastomer is completely cured under natural conditions to form a complex gel phase change heat storage structure as shown in Figures 2 to 4 .

[0091] Example 3

[0092] The embodiment provides a preparation method of a complex gel phase change heat storage structure, and the preparation process comprises the following steps:

[0093] Step one: a encapsulating model as shown in Figure 1 is printed by using a 3D printing method, the filling rate is set to be 18% so that the encapsulating model has sufficient strength, the wall thickness of the encapsulating model is set to be 0.8 mm so that the PVA solution is more easily drawn into the encapsulating model, and the printing material is selected to be nylon.

[0094] Step two: a PVA aqueous solution with a mass fraction of 20% is configured, an amount of sodium sulfate decahydrate equal to the mass of PVA is added into the PVA aqueous solution and stirred uniformly, and then the PVA aqueous solution containing the hydrated inorganic salt is drawn into the encapsulating model under the action of atmospheric pressure by vacuumizing.

[0095] Step three: the encapsulating model containing the PVA aqueous solution with the hydrated inorganic salt is frozen at-18 ℃ for 12 h, thawed at 26 ℃ for 1.5 h, and the freezing and thawing operation is cycled for three times until the PVA hydrogel is formed.

[0096] Step four: the high thermal conductive elastomer is formed by mixing the silicone rubber and the high thermal conductive material with a stirring rod as the encapsulating material, the encapsulating model containing the PVA hydrogel is immersed in the high thermal conductive elastomer before the high thermal conductive elastomer is cured, then the excess high thermal conductive elastomer on the surface of the encapsulating model is removed, the thickness of the encapsulating high thermal conductive elastomer is less than 1 mm, and the actual thickness is 0.5 mm; and the high thermal conductive elastomer is completely cured under natural conditions to form a complex gel phase change heat storage structure as shown in Figures 2 to 4 .

[0097] Example 4

[0098] The embodiment provides a preparation method of a complex gel phase change heat storage structure, and the preparation process comprises the following steps:

[0099] Step one: a encapsulating model as shown in Figure 1The packing model shown in the figure, in order to make the packing model has enough strength, set the filling rate to 22%, in order to make the PVA solution more easily into the packing model, set the packing model wall thickness to 0.7mm, the printing material is selected as PLA.

[0100] Step two: configure a PVA aqueous solution with a mass fraction of 8%, and add PVA equal mass of calcium chloride hexahydrate to it and stir uniformly, then the PVA aqueous solution containing hydrated inorganic salt is infiltrated into the packing model under the action of atmospheric pressure by vacuumizing.

[0101] Step three: freeze the packing model containing PVA aqueous solution with hydrated inorganic salt at-23℃ for 11h, thaw at 24℃ for 2.5h, cycle 5 times of freezing and thawing operation, until PVA hydrogel is formed.

[0102] Step four: mix the silicone rubber and high thermal conductivity material with a stirring rod to form a high thermal conductivity elastomer as a packaging material, before the high thermal conductivity elastomer is cured, the packing model containing PVA hydrogel is immersed in it, then remove the excess high thermal conductivity elastomer on the surface of the packing model, so that the thickness of the high thermal conductivity elastomer is less than 1mm, the actual thickness is 0.9mm, wait for the high thermal conductivity elastomer to be completely cured under natural conditions, and a complex gel phase change heat storage structure similar to Figures 2 to 4 The complex gel phase change heat storage structure shown in the figure.

[0103] Of course, Figures 2 to 4 The complex gel phase change heat storage structure shown in the figure is only an example, and is not limited to a specific structure. The complex gel phase change heat storage structure can be designed into other shapes that meet the needs according to actual application.

[0104] Example 5

[0105] The embodiment provides a preparation method of a complex gel phase change heat storage structure, and the preparation process comprises the following steps:

[0106] Step one: print the packing model shown in the figure by using 3D printing, in order to make the packing model has enough strength, set the filling rate to 18%, in order to make the PVA solution more easily into the packing model, set the packing model wall thickness to 0.8mm, the printing material is selected as nylon. Figure 1 Step two: configure a PVA aqueous solution with a mass fraction of 20%, and add PVA equal mass of sodium bisulfate dodecahydrate to it and stir uniformly, then the PVA aqueous solution containing hydrated inorganic salt is infiltrated into the packing model under the action of atmospheric pressure by vacuumizing.

[0107]

[0108] ​Step 3: Freeze the encapsulation model containing PVA aqueous solution with hydrated inorganic salts at -24℃ for 10 h, thaw at 23℃ for 2 h, and repeat the freezing and thawing operation 4 times until PVA hydrogel is formed.

[0109] Step 4: Silicone rubber and a high thermal conductivity material are thoroughly mixed using a stirring rod to form a high thermal conductivity elastomer, which is then used as an encapsulation material. Before the high thermal conductivity elastomer cures, the encapsulation model containing PVA hydrogel is immersed in it. Then, excess high thermal conductivity elastomer is removed from the surface of the encapsulation model, ensuring the thickness of the encapsulated high thermal conductivity elastomer is less than 1 mm (actual thickness is 0.5 mm). Under natural conditions, the high thermal conductivity elastomer is allowed to fully cure, forming a similar encapsulation material. Figures 2 to 4 The complex gel phase change thermal storage structure is shown.

[0110] To verify the temperature control performance of complex gel phase change thermal storage structures, such as Figure 5 As shown, five complex gel phase change thermal storage structures were prepared, with encapsulation model fill rates of 22%, 20%, 18%, 22%, and 18%, and PVA mass fractions of 5%, 10%, 20%, 8%, and 8%, respectively. The five complex gel phase change thermal storage structures were placed in a high and low temperature test chamber for cooling and heating tests, with the test environment temperature ranging from -40°C. o C to 0 o Between C and 20°C, the isothermal and thermal storage characteristics of the complex gel phase change thermal storage structure were studied by monitoring the temperature at the center point inside the structure. Figure 5 The temperature variation trend at the center of a complex gel phase change thermal storage structure is shown. Figure 5 It can be seen that for -20 o C to -10 o The complex gel phase change thermal storage structure at a specific temperature exhibits thermal storage performance. In two cooling-heating cycle tests, the temperature change trend at the center point of the complex gel phase change thermal storage structure remained consistent, verifying the repeatability of the experiment.

[0111] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a complex gel phase change heat storage structure, characterized in that, It comprises the following steps: Providing a packaging model; Filling a PVA aqueous solution containing hydrated inorganic salt into the packaging model by vacuum pumping to perform the first packaging; Freezing and thawing the packaging model after the first packaging to form a PVA hydrogel; Filling a high-thermal-conductivity elastomer into the surface of the packaging model after the PVA hydrogel is formed to perform the second packaging; Waiting for the high-thermal-conductivity elastomer to completely solidify to obtain a complex gel phase change heat storage structure; The packaging model is printed in a 3D printing manner to set the shape of the heat storage structure, and the filling rate of the packaging model is 18%-22%.

2. The method for preparing a complex gel phase change thermal storage structure according to claim 1, characterized in that, The material of the packaging model is a printing material doped with a high-thermal-conductivity material, and the printing material is one or more of PLA, ABS, and nylon; and the high-thermal-conductivity material is one or more of carbon nanotubes, carbon fibers, and graphene.

3. The method for preparing a complex gel phase change thermal storage structure according to claim 1, characterized in that, The mass fraction of PVA in the PVA aqueous solution is 5%-20%.

4. The method for preparing a complex gel phase change thermal storage structure according to claim 1, characterized in that, The hydrated inorganic salt includes one or more of sodium sulfate decahydrate, calcium chloride hexahydrate, and disodium hydrogen sulfate dodecahydrate, and the addition amount of the hydrated inorganic salt is the same as that of PVA.

5. The method of claim 1, wherein the complex gel phase change thermal storage structure is prepared by the steps of: The freezing and thawing of the packaging model after the first packaging comprises: Freezing the packaging model after the first packaging at-18--25℃ for 8-12 h, thawing at 20-26℃ for 1-3 h, and repeating the freezing and thawing operation for 3-7 times until the PVA hydrogel is formed.

6. The method of claim 1, wherein the complex gel phase change thermal storage structure is prepared by the steps of: The high-thermal-conductivity elastomer is a silicone rubber doped with a high-thermal-conductivity material, and the high-thermal-conductivity material is one or more of metal particles, liquid metal, carbon nanotubes, carbon fibers, and graphene.

7. The method for preparing a complex gel phase change thermal storage structure according to claim 1, characterized in that, The filling of the high-thermal-conductivity elastomer into the surface of the packaging model after the PVA hydrogel is formed comprises: Mixing the silicone rubber and the high-thermal-conductivity material to form the high-thermal-conductivity elastomer; and immersing the packaging model containing the PVA hydrogel into the high-thermal-conductivity elastomer before the high-thermal-conductivity elastomer is solidified to form a high-thermal-conductivity elastomer encapsulation layer on the surface of the packaging model.

8. The method for preparing a complex gel phase change thermal storage structure according to claim 1, characterized in that, The filling rate of the packaging model is variable, the wall thickness of the packaging model is less than 1 mm, and the thickness of the high-thermal-conductivity elastomer encapsulation layer is less than 1 mm.

9. A complex gel phase change thermal storage structure characterized by, The complex gel phase change heat storage structure is prepared according to the preparation method of any one of claims 1-8.

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