Double-layer polymer film manufacturing method based on electrocaloric effect and refrigerating device

Abstract

The invention discloses a double-layer polymer film manufacturing method based on an electrocaloric effect, which comprises the following steps: blending a terpolymer P (VDF-TRFE-CFE) and BSZMT nano powder, adding an N, N-dimethylformamide solvent, and stirring until the mixture is clarified to prepare a nano composite solution; spraying the nano composite solution on the surface of a glass slide under pressure to form a first layer of wet film; drying the glass slide on which the first layer of wet film is formed at a first temperature, and annealing the dried glass slide at a second temperature to form a first layer of polymer film; printing carbon paste on the surface of the first layer of polymer film to form an intermediate layer electrode; spraying the nano composite solution on the surface of the first layer of polymer film under pressure to form a second layer of wet film; drying the glass slide on which the second layer of wet film is formed at a third temperature, and annealing at a fourth temperature to form a second layer of polymer film; and a polymerization structure formed by clamping the middle layer electrode between the first layer polymerization film and the second layer polymerization film is stripped from the surface of the glass slide, so that the double-layer polymerization film with high heat dissipation efficiency can be obtained.

Description

Technical Field

[0001] This invention relates to the field of novel solid-state refrigeration technology, and in particular to a method for manufacturing a bilayer polymer film based on the electrocaloric effect and a refrigeration device. Background Technology

[0002] Currently, with the continuous improvement of electronic device performance and the continuous miniaturization of size, the heat generated during operation is increasing rapidly, making thermal management a critical factor restricting the stability and lifespan of electronic devices. To ensure the normal operation of electronic devices under high load and high integration conditions, developing efficient, low-power heat dissipation and cooling technologies suitable for micro-devices has become a continuous focus for those skilled in the art.

[0003] Existing thermal management solutions mainly include fan cooling, liquid cooling, and thermoelectric cooling. While fans and liquid cooling systems transfer heat through forced convection or coolant circulation, offering some heat dissipation performance, their complex structure, large size, and high power consumption make them unsuitable for the miniaturization and low-power requirements of portable electronic devices. Thermoelectric coolers based on the Peltier effect have no moving parts, but their application in miniaturized applications suffers from low cooling efficiency and high energy consumption, limiting their use. In recent years, electrothermal cooling technology has attracted attention due to its advantages such as no moving parts, fast response, and low noise. Existing electrothermal materials mostly use polyvinylidene fluoride (PVDF) and its terpolymer P (VDF-TRFE-CFE), achieving heat absorption and release through polarization changes induced by an applied electric field. Some technologies also introduce nanoparticles such as barium titanate and alumina into the PVDF matrix to improve dielectric properties and the electrothermal effect. Heat dissipation structures typically combine electrothermal materials with heat sinks, thermally conductive elements, and auxiliary fans for electronic chip temperature control.

[0004] However, existing cooling materials for electronic cards mostly employ a single-layer structure, resulting in limited cooling efficiency and energy density, insufficient heat conduction paths, and poor overall heat dissipation. To improve cooling performance, multi-layer polymer structures or complex auxiliary electric drive systems and heat dissipation devices are typically introduced, increasing structural complexity and energy consumption. The fabrication processes for existing electronic card materials still face challenges in ensuring the consistency and stability of polymeric thin films, affecting card performance and reliability. Therefore, existing technologies still need improvement to meet the demands of microelectronic devices for efficient heat dissipation, low energy consumption, and structural simplification. Summary of the Invention

[0005] This invention provides a method for manufacturing a bilayer polymer film based on the electrocardiogram effect and a refrigeration device to solve the technical problem of low refrigeration efficiency of traditional electrocardiogram effect single-layer structure films, which leads to limited heat dissipation performance of the refrigeration device.

[0006] To address the aforementioned technical problems, this invention provides a method for manufacturing a bilayer polymeric film based on the electrocardiogram effect, comprising: The terpolymer P(VDF-TRFE-CFE) and BSZMT nanopowder were blended together, and then N,N-dimethylformamide solvent was added. After stirring until the mixture became clear, a nanocomposite solution was prepared. The nanocomposite solution is pressure-sprayed onto the surface of a glass slide to form a first wet film. The glass slide forming the first wet film is dried at a first temperature and then annealed at a second temperature to form the first polymer film. Carbon paste is printed on the surface of the first polymer film to form an intermediate electrode; The nanocomposite solution is pressure-sprayed onto the surface of the first polymer film to form a second wet film; The glass slide forming the second wet film is dried at a third temperature and then annealed at a fourth temperature to form the second polymer film. The polymer structure formed by sandwiching the intermediate layer electrode between the first polymer film and the second polymer film is peeled off from the surface of the glass slide to obtain a double-layer polymer film.

[0007] Furthermore, 0.10–0.30 g of terpolymer P (VDF-TRFE-CFE) was weighed, and then 0.01–0.03 g of BSZMT nanopowder was added in batches at a ratio of 2–5 vol.%, and the mixture was stirred evenly to obtain a raw material mixture.

[0008] Furthermore, 1–3 mL of N,N-dimethylformamide solvent is added to the raw material mixture, and the mixture is stirred for 4–8 hours until the solution becomes clear, thereby obtaining a nanocomposite solution.

[0009] Furthermore, before blending with the terpolymer P (VDF-TRFE-CFE), the BSZMT nanopowder is ground using a high-energy ball milling method to control the average particle size range of the BSZMT nanopowder to be between 80-120 nm.

[0010] Furthermore, the nanocomposite solution is sprayed onto the surface of the glass slide and the surface of the first polymer film at the same spraying pressure, wherein the spraying pressure is set between 10-20 MPa.

[0011] Furthermore, the thickness of the first wet film and the first wet film are both in the range of 20-40µm.

[0012] Furthermore, the first temperature and the third temperature are both controlled within the range of 70℃-90℃, and the second temperature and the fourth temperature are both controlled within the range of 110℃-130℃.

[0013] Furthermore, after the polymer structure formed by sandwiching the intermediate layer electrode between the first polymer film and the second polymer film is peeled off from the surface of the glass slide, carbon paste needs to be printed on the lower surface of the first polymer film and the upper surface of the second polymer film to form the outer layer electrode.

[0014] On the other hand, the present invention also provides a cooling device, comprising a double-layer polymer film made by any of the methods described above, a first housing, a second housing, a chip, a heat sink, a flexible voltage isolation layer, and a driving power supply. The first housing is disposed on the upper end face of the second housing, and a mounting cavity is formed between the first housing and the second housing. A through hole is formed in the upper wall of the first housing, extending into the mounting cavity. The chip is disposed in the through hole. The flexible voltage isolation layer is disposed at the top of the mounting cavity, and the double-layer polymer film is disposed on the side of the flexible voltage isolation layer away from the chip. The heat sink is disposed at the bottom of the mounting cavity and spaced apart from the double-layer polymer film. The driving power supply is electrically connected to the intermediate layer electrode and two outer layer electrodes on the double-layer polymer film to apply voltage to the double-layer polymer film, so that the double-layer polymer film adheres to the heat sink or the chip.

[0015] Furthermore, the heat sink is a ceramic heat sink, and the distance between the ceramic heat sink and the double-layer polymer film ranges from 0.05mm to 0.15mm.

[0016] Compared with the prior art, the beneficial effects of the bilayer polymer film manufacturing method and refrigeration device based on the electrocardiogram effect of this invention are as follows: This invention provides a nanocomposite solution prepared by sequentially spraying, drying, and annealing a terpolymer P (VDF-TRFE-CFE), BSZMT nanopowder, and N,N-dimethylformamide onto a glass slide. Carbon paste is then printed during this process, resulting in a polymeric structure with two layers of polymeric films sandwiching a carbon electrode. This creates a polymeric film material with high electrocaloric effect performance. Compared to traditional single-layer structures, the bilayer polymeric film achieves synergistic optimization in structural design and material properties. When an external electric field is applied, the two polymer layers respond synchronously, enhancing the synergistic effect of internal dipole orientation and rearrangement, further amplifying the cooling range brought about by the electrocaloric effect. This allows the electrocaloric effect composite material to produce a larger reversible adiabatic temperature change effect, thereby achieving a larger temperature range, optimizing the heat diffusion path of the film layer, reducing heat retention within the film layer, and effectively improving the heat transfer rate. Overall, this invention, through the polymer structure design of a double-layer polymer film, enhances the adhesion performance of the film to solid surfaces such as heat sinks and chips at the microscopic level. Combined with a voltage-driven bonding method, it further shortens the heat conduction path, improves the interface heat dissipation efficiency, and avoids the heat transfer delay phenomenon caused by poor adhesion in traditional single-layer electrocard effect films. This significantly improves the cooling efficiency of the cooling device while reducing system power consumption and structural complexity, thus meeting the application requirements of high performance and low energy consumption. It greatly promotes the engineering application of electrocard effect materials and their cooling technology and has broad industrialization prospects.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] The accompanying drawings are provided for a better understanding of this solution and do not constitute a limitation of the invention. Wherein: Figure 1 This is a flowchart of the method for manufacturing a bilayer polymer film based on the electrocardiogram effect provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of an angle structure of a bilayer polymer film manufactured by the bilayer polymer film manufacturing method based on the electrocardiogram effect provided in an embodiment of the present invention. Figure 3 This is another angled structural diagram of a bilayer polymer film manufactured by the bilayer polymer film manufacturing method based on the electrocardiogram effect provided in the embodiments of the present invention; Figure 4 This is an exploded view of a bilayer polymer film manufactured by the bilayer polymer film manufacturing method based on the electrocardiogram effect provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the refrigeration device provided in an embodiment of the present invention; Figure 6 This is an exploded view of the refrigeration device provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the first housing in the refrigeration device provided in an embodiment of the present invention; Figure 8 This is a temperature response change graph comparing a double-layer polymer film and a single-layer electrocard film provided in an embodiment of the present invention.

[0019] In the figure, 10 is a cooling device; 11 is a double-layer polymer film; 111 is a first polymer film; 112 is a second polymer film; 113 is an intermediate electrode; 114 is an outer electrode; 12 is a first housing; 121 is a through hole; 13 is a second housing; 14 is a chip; 15 is a heat sink; and 16 is a flexible voltage isolation layer. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0021] In the description of this invention, it should be noted that the directional terms such as "center", "upper", "lower", "inner", and "outer" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "at least" means one or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] For ease of explanation later, let's first clarify that the electrocaloric effect refers to the reversible adiabatic temperature change of certain dielectric materials under the influence of an applied electric field. Its essence stems from the rearrangement of ordered and disordered dipoles within the material under the influence of an electric field: when an electric field is applied, the originally disordered dipoles within the material reorient, increasing the system's order and decreasing its entropy (i.e., disorder). According to the second law of thermodynamics, to maintain total energy balance, the material's temperature rises. When the electric field is removed, the dipoles lose their constraint and tend towards disorder again, increasing the system's entropy, causing the material to absorb heat and cool down, thus achieving a temperature decrease. Because this process is highly reversible, heat transfer and temperature control can be achieved through cyclical application and removal of the electric field. In practical applications, electrocaloric materials are often used in combination with heat exchange structures (such as fans). By applying an electric field to raise the material's temperature and transfer heat to a heat source, and then removing the electric field to cool it down and absorb heat from the cooled object, this cycle repeats, forming a miniature refrigeration system without mechanical moving parts. Due to its fast response speed, compact structure, easy electronic control, noiseless operation, and excellent energy-saving and environmental protection potential, the electrocaloric effect has become an important development direction for the next generation of solid-state refrigeration technology. It enables devices to achieve significant cooling efficiency in a small volume, making it suitable for electronic devices with high temperature control accuracy requirements, especially for chip heat dissipation, flexible electronics, and micro coolers.

[0025] like Figure 1-4 As shown, this embodiment of the invention provides a bilayer polymeric film 11 based on the electrocardiogram effect. Its polymeric structure includes a first polymeric film 111, a second polymeric film 112, an intermediate electrode 113, and two outer electrodes 114. The intermediate electrode 113 is screen-printed onto the surface of the first polymeric film 111. The second polymeric film 112 is sprayed onto the first polymeric film 111, sandwiching the intermediate electrode 113 between them. The two outer electrodes 114 are respectively screen-printed onto the outer surfaces of the first and second polymeric films 111 and 112. The specific manufacturing method of this bilayer polymeric film 11 based on the electrocardiogram effect is as follows: S1: After blending the terpolymer P (VDF-TRFE-CFE) and BSZMT nanopowder, N,N-dimethylformamide solvent was added and stirred until clear to obtain a nanocomposite solution; S2: The nanocomposite solution is pressure-sprayed onto the surface of a glass slide to form the first wet film; S3: The glass slide forming the first wet film is dried at a first temperature and then annealed at a second temperature to form the first polymer film 111; S4: Print carbon paste on the surface of the first polymer film 111 to form the intermediate electrode 113; S5: The nanocomposite solution is pressure sprayed onto the surface of the first polymer film 111 to form a second wet film; S6: The glass slide forming the second wet film is dried at a third temperature and then annealed at a fourth temperature to form the second polymer film 112; S7: Peel the polymer structure formed by sandwiching the intermediate layer electrode 113 between the first polymer film 111 and the second polymer film 112 from the surface of the glass slide to obtain the double-layer polymer film 11. S8: After the polymer structure formed by sandwiching the intermediate layer electrode 113 between the first polymer film 111 and the second polymer film 112 is peeled off from the surface of the glass slide, carbon paste needs to be printed on the lower surface of the first polymer film 111 and the upper surface of the second polymer film 112 to form the outer layer electrode 114. Only in this way can the final double-layer polymer film 11 be obtained. This structure can be directly integrated into various microchips or refrigeration devices to achieve efficient temperature control and thermal management functions driven by electric field.

[0026] In this embodiment of the invention, a nanocomposite solution was prepared by sequentially spraying, drying, and annealing a terpolymer P (VDF-TRFE-CFE), BSZMT nanopowder, and N,N-dimethylformamide onto a glass slide and mixing them. Carbon paste was then printed in the middle of the mixture to prepare a polymeric structure with two polymeric films sandwiching a carbon electrode. This resulted in a polymeric film material with high electrocaloric effect performance. Compared with the traditional single-layer structure, the double-layer polymeric film 11 achieves synergistic optimization in structural design and material properties. When an external electric field is applied, the two polymer layers can respond synchronously, enhancing the synergistic effect of internal dipole orientation and rearrangement, further amplifying the cooling range brought about by the electrocaloric effect, and enabling the electrocaloric effect composite material to produce a larger reversible adiabatic temperature change effect, thereby achieving a larger temperature range, optimizing the heat diffusion path of the film layer, reducing the heat retention phenomenon inside the film layer, and thus effectively improving the heat transfer rate. Overall, this invention, through the polymer structure design of the double-layer polymer film 11, enhances the adhesion performance between the film and solid surfaces such as the heat sink 15 and the chip 14 at the microscopic level. Combined with the voltage-driven bonding method, it further shortens the heat conduction path, improves the interface heat dissipation efficiency, and avoids the heat transfer delay phenomenon caused by the poor adhesion of traditional single-layer electrocard effect films. This significantly improves the cooling efficiency of the cooling device 10, while reducing system power consumption and structural complexity, thus meeting the application requirements of high performance and low energy consumption. It greatly promotes the engineering application of electrocard effect materials and their cooling technology and has broad industrialization prospects.

[0027] The reason why the bilayer polymer film 11 structure can significantly improve heat dissipation efficiency is mainly due to its systematic optimization at multiple levels, such as material composition and electric field response mechanism. As explained above, the electrocaloric effect is essentially an electroinduced temperature change behavior, which relies on the reversible adiabatic temperature change effect generated by the ordered arrangement of dipoles under the action of an electric field. In the traditional single-layer structure, the response capability of the polymer is limited by the dipole orientation density and orientation freedom of the material itself, resulting in a small cooling range. In the embodiments of the present invention, a nanocomposite solution formed by mixing ternary copolymer P (VDF-TRFE-CFE), BSZMT nanopowder and N,N-dimethylformamide is used to form two independent polymer films by spraying in two stages. Carbon paste electrodes are set in the middle and outer layers, allowing the upper and lower polymer layers to respond synchronously under the action of an electric field. This enhances the synergy of dipole rearrangement in the overall material system. As a result, the electrocaloric effect amplitude is greatly improved, which can achieve a stronger temperature jump and provide a larger temperature difference drive for the subsequent heat exchange process, which helps to quickly dissipate heat.

[0028] Ternary copolymer P(VDF-TRFE-CFE) is a ferroelectric polymer material based on fluorinated polymers. Its full name is vinylidene fluoride-trifluoroethylene-chlorofluoroethylene terpolymer. The polymer matrix is ​​P(VDF-TRFE-CFE) ternary copolymer ferroelectric polymer, possessing multiple performance advantages. Its most significant characteristic is excellent electrocaloric effect; under the action of an applied electric field, it can generate a significant temperature change through a ferroelectric-relaxation phase transition, and this phase transition can be achieved at a relatively low electric field, greatly reducing driving energy consumption. Simultaneously, ternary copolymer P(VDF-TRFE-CFE) exhibits low dielectric loss characteristics, maintaining high energy efficiency even during dynamic cooling processes with frequent start-stop cycles, avoiding performance degradation due to heat accumulation. Furthermore, this material has excellent flexibility and strong film-forming properties, adaptable to various preparation processes such as spraying and peeling, and is particularly suitable for constructing multilayer polymer structures, making it especially friendly for the integrated manufacturing of micro-devices. The incorporated BSZMT nanopowder is a modified perovskite-structured ceramic material with the chemical formula Ba. 0.7 Sr 0.3 Zr x (Ti 0.999 Mn 0.001 ) 0.95 O3, possessing high dielectric constant, low dielectric loss, and excellent thermal stability, can be composited with the ternary copolymer P(VDF-TrFE-CFE) to significantly enhance the electrocaloric response and thermal diffusivity of the polymer film, providing synergistic electrothermal regulation support for the bilayer structure. Specifically, this material exhibits high dielectric constant, low dielectric loss, and good thermal stability; its multi-component doping design maintains the stability of the perovskite structure while utilizing Zr... 4+ For Ti 4+Partial substitution by Mn enhances the polarization response of the material, while a small amount of Mn 2+ Doping further reduces dielectric loss and suppresses leakage current. The nanoscale particle size ensures good interfacial compatibility with the polymer matrix, enabling the formation of a dense, dispersed network structure. This enhances dielectric properties while effectively improving the thermal conductivity and structural stability of the composite film, thereby synergistically improving electrocaloric response and material durability, providing crucial support for high-performance solid-state refrigeration.

[0029] In the preparation process, N,N-dimethylformamide plays a crucial role as a solvent in this composite material system. Firstly, N,N-dimethylformamide possesses strong polarity and excellent solubility, effectively dissolving fluoropolymers such as the terpolymer P (VDF-TRFE-CFE) and dispersing BSZMT nanoparticles, ensuring uniform mixing of the system components at the microscopic level. Secondly, the high boiling point of N,N-dimethylformamide facilitates slow and uniform solvent evaporation during film formation processes such as spraying or spin coating, resulting in a dense polymeric film structure without significant pores, thus improving the dielectric uniformity and mechanical stability of the material. Furthermore, N,N-dimethylformamide exhibits good adhesion to the substrate, improving film quality and interfacial bonding, which is beneficial for the stable execution of subsequent preparation steps such as electrode printing, interlayer stacking, and peeling. Therefore, N,N-dimethylformamide is not only a solvent in a physical sense but also an indispensable "processing control factor" in constructing high-performance electrocardiograph composite film materials.

[0030] When peeling off the polymer structure formed by the intermediate electrode 113 sandwiched between the first polymer film 111 and the second polymer film 112, physical peeling or solvent-assisted peeling methods are commonly used. In the specific operation, first ensure that the polymer structure is fully cured on the slide surface to form an integral film structure with sufficient mechanical strength. Then, gently pry up a corner of the polymer layer along the edge of the slide with tweezers, slowly applying uniform external force to peel it off as a whole. Avoid excessive force that could damage the film layer. If the polymer adheres firmly to the slide, a suitable solvent (such as water or ethanol, depending on the slide pretreatment material) can be used to gently wet the edges to reduce interfacial adhesion and assist peeling. In special cases, a peelable isolation layer (such as a PVA water-soluble film or a hydrophobic treatment agent) can be pre-coated onto the slide surface to facilitate smooth peeling of the entire film layer after polymer curing. After peeling, the film layer should be immediately smoothed and dried for storage to prevent structural warping or performance degradation.

[0031] It should be noted that glass is the preferred material for the glass slide used to support the polymer film. This is due to its excellent mechanical strength, chemical stability, and outstanding transparency. Glass also possesses high thermal stability and excellent resistance to chemical corrosion, effectively handling the high temperatures, solvents, and chemicals involved in the preparation process, ensuring the stability of the film structure. Furthermore, the smooth surface of glass is easy to handle and clean, providing an ideal foundation for the uniform coating and subsequent peeling of the polymer film, guaranteeing high-quality film formation. The high transparency of glass also facilitates precise monitoring of film thickness and quality during the preparation process, thereby optimizing the process. In summary, glass, as a glass slide material, provides robust support, an excellent processing platform, and significant practical advantages in this composite material system.

[0032] In an optional embodiment of the present invention, 0.10–0.30 g of terpolymer P (VDF-TRFE-CFE) is weighed, and then 0.01–0.03 g of BSZMT nanopowder is added in batches at a ratio of 2–5 vol.%, and mixed evenly to obtain a raw material mixture; 1–3 mL of N,N-dimethylformamide solvent is added to the raw material mixture, and the mixture is stirred for 4–8 h until the solution is clear to obtain a nanocomposite solution.

[0033] Specifically, by adding BSZMT nanopowder to the terpolymer P (VDF-TRFE-CFE) at a ratio of 2–5 vol.%, the uniform distribution of the nanopowder in the polymer matrix can be effectively ensured. This allows for full utilization of the high dielectric constant and excellent thermal stability of the BSZMT nanopowder, enhancing the electrocaloric effect of the composite material, optimizing its electrical and thermal properties, and thus improving heat dissipation efficiency and cooling effect. Subsequently, N,N-dimethylformamide is added as a solvent, and prolonged stirring facilitates the good dissolution and dispersion of the terpolymer P (VDF-TRFE-CFE) and the BSZMT nanopowder. N,N-dimethylformamide not only possesses excellent solubility but also ensures the uniform distribution of BSZMT nanopowder in the polymer matrix, preventing agglomeration. Stirring for 4–8 hours further improves the clarity of the solution, ensuring better homogeneity of the final nanocomposite solution.

[0034] Through this process, the prepared nanocomposite solution can provide higher performance, especially in terms of electrocaloric effect and thermal conduction, meeting the requirements of refrigeration and thermal management devices; at the same time, the optimized solution and mixing process also provides a stable foundation for subsequent thin film preparation, ensuring that the composite material has ideal structure and functionality.

[0035] In an optional embodiment of the present invention, the BSZMT nanopowder is milled using a high-energy ball milling method before being blended with the terpolymer P (VDF-TRFE-CFE) so that the average particle size range of the BSZMT nanopowder is controlled between 80-120 nm.

[0036] Specifically, high-energy ball milling is a commonly used physical processing technique. Through the collision, friction, and shearing forces between the powder and high-speed rotating milling media (such as steel balls or ceramic balls), the powder particles are refined and uniformly dispersed, and the particle size and morphology can be controlled. This method not only effectively reduces particle size but also improves powder dispersibility and surface activity. High-energy ball milling can control the particle size of BSZMT nanopowder between 80-120 nm, ensuring uniform distribution of the nanopowder within the terpolymer P(VDF-TRFE-CFE) and avoiding agglomeration of large particles. By controlling particle size and dispersibility, BSZMT nanopowder can better integrate with the terpolymer matrix, enhancing interfacial contact in the composite material and improving the synergistic effect of electrocaloric effects. Smaller nanopowder particles can form more interfaces within the polymer, thereby enhancing the electrothermal effect and thermal management capabilities, thus improving the performance of the composite material, particularly in terms of electrocaloric effects and thermal conductivity.

[0037] The terpolymer P(VDF-TRFE-CFE) is generally prepared via free radical copolymerization. Its preparation typically uses fluorinated vinylidene (VDF), trifluorochloroethylene (TRFE), and fluorinated cyclohexene (CFE) as monomers, synthesized through a high-temperature and high-pressure free radical polymerization reaction. During the reaction, appropriate solvents and initiators are required to ensure sufficient polymerization of the monomers and to allow the reaction to proceed under suitable temperature and pressure. First, VDF, TRFE, and CFE are mixed in a specific molar ratio, and a reaction solvent, such as N,N-dimethylformamide (DMF) or other suitable solvents, is added. Next, a free radical initiator (such as a peroxide or azo compound) is added, and the mixture is heated to the desired reaction temperature, typically between 150°C and 200°C. The reaction time depends on the reaction conditions and the required degree of polymerization, usually ranging from several hours to over ten hours. After the reaction, cooling, solvent removal, and purification steps are performed to finally obtain the desired P(VDF-TRFE-CFE) terpolymer.

[0038] In an optional embodiment of the present invention, the nanocomposite solution is sprayed onto the surface of the glass slide and the surface of the first polymer film 111 at the same spraying pressure, with the spraying pressure set between 10-20 MPa.

[0039] Specifically, the nanocomposite solution is sprayed onto the surface of the glass slide and the surface of the first polymer film 111 at the same spraying pressure. Setting the spraying pressure between 10-20 MPa ensures the uniformity and adhesion of the coating. Within this pressure range, the nanocomposite solution can smoothly cover the substrate surface, avoiding the formation of bubbles or uneven coating. Appropriate spraying pressure helps control the coating thickness, ensures the structural stability of the film, and optimizes subsequent processes, ensuring that the composite material possesses good electrothermal effects and thermal management performance.

[0040] In practical operation, high-precision pneumatic spraying equipment, such as pneumatic spray guns, automated atomizing sprayers, or ultrasonic spraying systems, can be used to spray nanocomposite solutions. Pneumatic spray guns are suitable for small-batch laboratory preparation, offering flexible operation and easy control of spray pressure and spray width. Automated atomizing sprayers are suitable for large-area, high-uniformity industrial preparation, enabling precise spray control and repeatable operation. Ultrasonic spraying equipment, due to its low atomization pressure and extremely fine droplet size, is suitable for preparing ultra-thin, uniform functional coatings, especially for polymer-based polymer film systems with high requirements for film thickness and surface quality. The flexible selection of these devices based on experimental needs and process parameters helps improve coating quality and system stability.

[0041] In an optional embodiment of the present invention, the thickness of the first wet film and the first wet film are both in the range of 20-40µm.

[0042] Specifically, the thicknesses of both the first and second wet films are controlled within the range of 20–40 µm, which has significant beneficial effects. This thickness range allows the polymer film to maintain good mechanical strength while possessing excellent flexibility and conformability, facilitating tight adhesion with the heat sinks 15 or chips 14 on both sides during application. The appropriate thickness effectively buffers interfacial stress, reduces the risk of delamination due to thermal expansion and contraction, and improves the overall stability and service life of the composite material. Furthermore, an excessively thick film layer avoids material waste while ensuring thermal response sensitivity and uniform conduction of the electric field, which is beneficial for improving electrocardiogram performance and thermal management efficiency.

[0043] In an optional embodiment of the present invention, the first temperature and the third temperature are both controlled within the range of 70°C-90°C, and the second temperature and the fourth temperature are both controlled within the range of 110°C-130°C.

[0044] Specifically, the first and third temperatures for drying the first and second wet films are controlled within the range of 70℃-90℃. The main purpose is to promote the complete evaporation of the solvent N,N-dimethylformamide. N,N-dimethylformamide has a boiling point of approximately 153℃. By controlling the drying temperature within the 70℃-90℃ range, and by extending the drying time combined with the high specific surface area of ​​the film structure, effective and gradual solvent removal can be achieved. This avoids blistering, cracking, or uneven thickness caused by vigorous evaporation, thus ensuring the quality and density of the film.

[0045] Subsequently, the dried first and second wet films were annealed at a second and a fourth temperature range of 110℃-130℃. This temperature range falls within the crystallization transition temperature range of the terpolymer P(VDF-TRFE-CFE), effectively inducing polymer chain rearrangement, improving its crystal structure order, and enhancing the ferroelectricity and electrocaloric effect response of the material. Simultaneously, within this temperature range, the interfacial compatibility between the BSZMT nanofiller and the polymer matrix is ​​further optimized, contributing to enhanced interfacial bonding and synergistic effects, and improving the stability and functional properties of the composite material.

[0046] Overall, the zoned control of drying and annealing temperatures takes into account the three key aspects of solvent removal, structural film formation, and crystal regulation, ensuring a balanced improvement in the microstructure and macroscopic properties of the composite film, which is conducive to its efficient and stable application in scenarios such as electronic cooling and thermal management.

[0047] like Figure 5-7 As shown, in another aspect, the present invention also provides a refrigeration device 10, the high-efficiency refrigeration performance of which is supported by a high-performance composite material obtained by the aforementioned preparation method. The device includes a double-layer polymer film 11, a first shell 12, a second shell 13, a chip 14, a heat sink 15, a flexible voltage isolation layer 16, and a driving power supply.

[0048] A first housing 12 is disposed on the upper end face of a second housing 13, and a mounting cavity is formed between the first housing 12 and the second housing 13. A through hole 121 is provided on the upper wall of the first housing 12, extending into the mounting cavity. A chip 14 is disposed in the through hole 121. A flexible voltage isolation layer 16 is disposed at the top of the mounting cavity, and a double-layer polymer film 11 is disposed on the side of the flexible voltage isolation layer 16 away from the chip 14. A heat sink 15 is disposed at the bottom of the mounting cavity and is spaced apart from the double-layer polymer film 11. A driving power supply is electrically connected to the intermediate layer electrode 113 and the two outer layer electrodes 114 on the double-layer polymer film 11 to apply voltage to the double-layer polymer film 11, so that the double-layer polymer film 11 is attached to the heat sink 15 or the chip 14.

[0049] Specifically, this embodiment of the invention constructs a composite cooling device 10 consisting of a double-layer polymer film 11, a first housing 12, a second housing 13, a chip 14, a heat sink 15, a flexible voltage isolation layer 16, and a driving power supply (not shown in the figure), achieving precise coordination and efficient integration in structural design and functional implementation. A sealed mounting cavity is formed between the first housing 12 and the second housing 13. The chip 14 is embedded in a through-hole 121 on the first housing 12, achieving precise positioning with the internal components and avoiding displacement interference. The flexible voltage isolation layer 16 at the top of the mounting cavity not only effectively ensures the stability of the electric field but also improves the flexibility and structural compatibility of the entire device, laying the foundation for efficient thermal coupling between the double-layer polymer film 11, the chip 14, and the heat sink 15. The specific working principle is as follows: The double-layer polymer film 11, as the core cooling unit, is fixed on the side of the flexible voltage isolation layer 16 away from the chip 14. It is connected to the driving power supply through the intermediate layer electrode 113 and the two outer layer electrodes 114 respectively. When an alternating voltage is applied, a significant electrocaloric effect can be generated under low driving field strength, resulting in instantaneous heat absorption or release. Under the control of the driving voltage, the double-layer polymer film 11 periodically adheres to and separates from the chip 14 and the heat sink 15, forming a directional heat transfer path. During the cooling cycle, heat is rapidly absorbed from the surface of the chip 14 and efficiently guided to the heat sink 15, achieving rapid cooling of the chip 14.

[0050] Meanwhile, this structure fully utilizes the excellent flexibility and response speed of the double-layer polymer film 11, maintaining a tight and stable bonding interface while avoiding local stress concentration or void formation, significantly improving heat transfer efficiency and thermal response sensitivity. The addition of the intermediate electrode layer further optimizes the electric field distribution, making the electrocardiogram response more uniform and avoiding local overheating or cold spots. In addition, the heat sink 15 is located at the bottom of the mounting cavity and is arranged alternately with the polymer film, which is beneficial for guiding the heat flow direction and improving the overall heat dissipation capacity of the system, preventing heat accumulation effects.

[0051] The innovation of this structure lies in the efficient dynamic bonding between the chip 14 surface and the polymer film and heat sink 15 through the rational arrangement of interlayer layers and the synergistic effect of electrothermal function. This overcomes the problems of low heat exchange efficiency and loose bonding of traditional solid-state cooling materials, ensuring the continuous thermal management and stable operation of the device under high load and high density working environment. It has broad practical prospects and industrialization value.

[0052] In summary, the refrigeration device 10 of this invention has the advantages of simple process and low cost. The pressure spraying process is used to prepare the double-layer composite material, ensuring uniform film thickness and strong controllability, significantly reducing production costs and improving production efficiency. Compared with traditional complex film preparation methods, spraying technology not only simplifies the process but also has good compatibility, facilitating large-scale production. Furthermore, the device's structural design is flexible and can be customized according to actual needs, adapting to electronic devices of different sizes and power ratings. It exhibits high flexibility, particularly in adjusting the dimensions of the chip 14 layers, the voltage isolation layer, the double-layer polymer film 11, and the heat sink 15, meeting the needs of various application scenarios and enhancing the device's versatility and applicability.

[0053] like Figure 8 As shown, the temperature change (ΔT) versus time curves of a single-layer electrocardiogram (ECG) film based on 0.20 g of P(VDF-TRFE-CFE) terpolymer and a bilayer polymeric film 11 prepared by blending 0.20 g of terpolymer P(VDF-TRFE-CFE) material, 0.02 g of BSZMT nanoparticles, and 2 ml of N,N-dimethylformamide solvent under the same electric field are displayed. It is easily observed from the figure that the bilayer polymeric film exhibits a larger ΔT peak value in each cycle, significantly higher than that of the single-layer ECG film, indicating a stronger ECG effect. Furthermore, the bilayer polymeric film has a wider temperature range and a steeper response curve, indicating a more rapid heating and cooling process under the electric field. These results demonstrate that by introducing high-dielectric-constant BSZMT nanoparticles as filler and constructing a bilayer polymeric structure, the performance of the ECG material is significantly improved, not only enhancing the ECG effect efficiency but also broadening the operating temperature window of the device, laying the foundation for its practical application in high-performance solid-state refrigeration.

[0054] In an optional embodiment of the present invention, the heat sink 15 is a ceramic heat sink 15, and the distance between the ceramic heat sink 15 and the double-layer polymer film 11 is in the range of 0.05mm-0.15mm.

[0055] Specifically, by using a ceramic heat sink 15 and controlling the distance between it and the double-layer polymer film 11 within the range of 0.05mm to 0.15mm, the following significant benefits are achieved: First, the ceramic material has excellent thermal conductivity, which can effectively improve heat dissipation efficiency and quickly conduct the heat generated by the chip 14 to the surface of the heat sink 15, reducing the overheating problem of the chip 14, thereby improving the working stability and lifespan of the chip 14; Second, the high thermal stability and oxidation resistance of the ceramic heat sink 15 enable it to maintain good performance in high-temperature working environments, ensuring the stability and reliability of the cooling device 10 during long-term operation.

[0056] Furthermore, the spacing between the ceramic heat sink 15 and the double-layer polymer film 11 is designed to be between 0.05 mm and 0.15 mm, which helps to maintain optimal contact efficiency while ensuring good heat dissipation. A smaller spacing maximizes the thermal contact area between the double-layer polymer film 11 and the heat sink 15, reduces thermal resistance, and allows heat to be transferred more efficiently from the polymer film to the heat sink 15, further enhancing the overall efficiency of the heat dissipation system. Controlling the spacing range also avoids a decrease in heat dissipation performance due to an excessively large spacing, or excessive contact pressure due to an excessively small spacing, which could affect the stability of the materials. Therefore, a reasonable spacing design not only improves heat dissipation efficiency but also helps maintain the overall stability of the system, ensuring the continuous performance of the cooling device 10 during efficient operation.

[0057] In an optional embodiment of the present invention, the flexible voltage isolation layer 16 is a PI tape.

[0058] Specifically, the flexible voltage isolation layer 16 uses PI (polyimide) tape. PI tape has excellent electrical insulation properties, which can effectively isolate the voltage between the double-layer polymer film 11 and other electronic components (such as chip 14 and heat sink 15), avoiding damage caused by short circuits or excessive voltage. Its high dielectric strength and excellent electrical stability ensure that the voltage isolation layer can stably and effectively perform its electrical isolation function during long-term operation, preventing electrical interference and malfunctions.

[0059] Furthermore, the flexibility of the PI tape allows the voltage isolation layer to adapt to the periodic bonding and separation between the double-layer polymer film 11 and the chip 14 and heat sink 15. During the operation of the cooling device 10, the voltage film periodically contacts and separates from the heat sink 15 or chip 14 as the voltage changes. The flexibility of the PI tape ensures that the voltage isolation layer is not easily damaged under these periodic operations, while maintaining the stability and reliability of the electrical isolation function. The flexibility also reduces material cracking or failure due to mechanical stress, thereby improving the long-term stability and durability of the entire system. In summary, the PI tape not only provides excellent voltage isolation but also ensures the reliability and flexibility of the system during dynamic operation, making it particularly suitable for applications requiring periodic bonding and separation, thus improving the overall performance and safety of the device.

[0060] It should be noted that PI tape (polyimide tape) is a high-performance tape with polyimide as its base material. Due to its excellent high-temperature resistance, chemical resistance, electrical insulation, and mechanical strength, it is widely used in various industries such as electronics, aerospace, and automotive. PI tape can withstand temperatures from -269°C to +400°C, making it suitable for extreme environments without deformation or loss of performance. Furthermore, polyimide materials have excellent electrical insulation properties and are often used for electrical isolation and protection of electronic components. It also possesses good chemical resistance, exhibiting strong tolerance to acids, alkalis, solvents, and other chemicals. Simultaneously, its high mechanical strength and flexibility allow it to be applied to complex surfaces and withstand certain tensile stresses. With these characteristics, PI tape has become an important choice for electrical isolation, protection, and shielding materials, and is widely used in circuit board repair, refrigeration equipment, and other fields.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for manufacturing a double-layered polymeric film based on the electrocaloric effect, characterized in that, The application relates to a method for preparing a double-layer polymer film. The method comprises the following steps: a ternary copolymer P(VDF-TRFE-CFE) and BSZMT nanopowder are blended, then N,N-dimethylformamide solvent is added, and the mixture is stirred until clear to obtain a nanocomposite solution; the nanocomposite solution is pressure sprayed on the surface of a glass slide to form a first layer of wet film; the glass slide with the first layer of wet film is dried at a first temperature and then annealed at a second temperature to form a first layer of polymer film; carbon paste is printed on the surface of the first layer of polymer film to form an intermediate layer electrode; the nanocomposite solution is pressure sprayed on the surface of the first layer of polymer film to form a second layer of wet film; the glass slide with the second layer of wet film is dried at a third temperature and then annealed at a fourth temperature to form a second layer of polymer film; 2. The method of claim 1, wherein the method is a method of manufacturing an electrically based dual-layer polymeric film. the intermediate layer electrode is sandwiched between the polymer structure formed by the first layer of polymer film and the second layer of polymer film, and then peeled off from the surface of the glass slide to obtain a double-layer polymer film.

3. The method of claim 2, wherein the method further comprises the step of: 0.10-0.30 g of a ternary copolymer P(VDF-TRFE-CFE) is weighed, then 0.01-0.03 g of BSZMT nanopowder is added in batches at a proportion of 2-5 vol.%, and the mixture is uniformly mixed to obtain a raw material mixture. ​ 4. The method of claim 2, wherein the method further comprises the step of: 1-3 mL of N,N-dimethylformamide solvent is added to the raw material mixture, and the mixture is stirred for 4-8 h until the solution is clear, to obtain a nanocomposite solution. ​ 5. The method of claim 1, wherein the method is a method of manufacturing an electrically based dual-layer polymeric film. Before being blended with the ternary copolymer P(VDF-TRFE-CFE), the BSZMT nanopowder is ground by using a high-energy ball milling method, so that the average particle size of the BSZMT nanopowder is controlled in a range of 80-120 nm.

6. The method of claim 4, wherein the method further comprises the step of: The nanocomposite solution is sprayed on the surface of the glass slide and the surface of the first layer of polymer film at the same spraying pressure, and the spraying pressure is set in a range of 10-20 MPa. ​ 7. The method of claim 1, wherein the method further comprises the step of: The thickness of the first layer of wet film and the first layer of wet film is in a range of 20-40 mu m. ​ 8. The method of claim 1-6, wherein the method is characterized by, The first temperature and the third temperature are both controlled in a range of 70 DEG C-90 DEG C, and the second temperature and the fourth temperature are both controlled in a range of 110 DEG C-130 DEG C. After the intermediate layer electrode is sandwiched between the polymer structure formed by the first layer of polymer film and the second layer of polymer film and then peeled off from the surface of the glass slide, carbon paste is printed on the lower surface of the first layer of polymer film and the upper surface of the second layer of polymer film to form an outer layer electrode.

9. A refrigeration apparatus characterized by comprising: The double-layer polymeric film manufactured by the method of any one of claims 1-7, further comprising a first shell, a second shell, a chip, a heat sink, a flexible voltage isolation layer, and a driving power source, the first shell is arranged on the upper end face of the second shell, a mounting cavity is formed between the first shell and the second shell, a through hole is formed in the upper wall of the first shell and extends to the mounting cavity, the chip is arranged in the through hole, the flexible voltage isolation layer is arranged at the top of the mounting cavity, the double-layer polymeric film is arranged on the side of the flexible voltage isolation layer away from the chip, the heat sink is arranged at the bottom of the mounting cavity and is spaced apart from the double-layer polymeric film, and the driving power source is electrically connected with the middle layer electrode and the two outer layer electrodes of the double-layer polymeric film to apply voltage to the double-layer polymeric film, so that the double-layer polymeric film is attached to the heat sink or the chip.

10. The refrigeration appliance of claim 9, wherein, The heat sink is a ceramic heat sink, and the distance between the ceramic heat sink and the double-layer polymeric film is in the range of 0.05mm-0.15mm.

Images