Phase change radiator, thermoelectric device enhanced by phase change thermal management and preparation method of thermoelectric device

Abstract

The invention belongs to the technical field of thermoelectric power generation, and particularly relates to a phase change radiator, a thermoelectric device enhanced through phase change heat management and a preparation method of the thermoelectric device. The phase change radiator comprises a heat conduction module and a phase change module, the heat conduction module is arranged at the hot end of a thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device; the heat conduction module is made of a thermosetting resin-based composite material, and the phase change module is made of a paraffin-based composite material. The thermal contact resistance between the phase-change radiator and the thermoelectric device is low, the phase-change radiator has good heat dissipation performance, the temperature difference between the cold end and the hot end of the thermoelectric device can be guaranteed, and then the output performance of the thermoelectric device is enhanced. Meanwhile, the phase change radiator is small in density and low in cost, and can meet the adaptation requirements of various thermoelectric devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermoelectric power generation, and in particular relates to a phase change heat sink, a thermoelectric device utilizing phase change thermal management enhancement, and a preparation method thereof. Background Art

[0002] In daily life, most of the energy is released into the environment in the form of heat energy, which can be well collected by thermoelectric devices for use in low-energy micro-devices. However, the output performance of thermoelectric devices is related to factors such as the temperature difference between the hot and cold ends, the thermoelectric properties of the thermoelectric material itself, and the size and structure design of the thermoelectric arm. Therefore, increasing the temperature difference between the two ends of the thermoelectric arm is an effective way to improve the output performance of thermoelectric devices.

[0003] Currently, the output performance of thermoelectric devices has been improved by using heat sinks made of metal materials (such as copper, aluminum, etc.). However, the rigidity of the metal material itself leads to an extremely high contact thermal resistance between the heat sink and the thermoelectric device, which is obviously not conducive to the transfer of heat. Summary of the invention

[0004] The purpose of the present invention is to provide a phase change heat sink, a thermoelectric device enhanced by phase change thermal management, and a preparation method thereof. The phase change heat sink provided by the present invention reduces the contact thermal resistance between interfaces, can effectively increase the temperature difference between the two ends of the thermoelectric device, and thus improve the output performance of the thermoelectric device.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a phase change heat sink, comprising a heat conduction module and a phase change module, wherein the heat conduction module is arranged at the hot end of a thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device;

[0007] The material of the heat conduction module is a thermosetting resin-based composite material, the thermosetting resin-based composite material includes a thermosetting resin matrix and a first modified boron nitride dispersed in the thermosetting resin matrix, and the first modified boron nitride includes a silane coupling agent-modified boron nitride;

[0008] The material of the phase change module is a paraffin-based composite material, which includes a paraffin-based matrix and a second modified boron nitride dispersed in the paraffin-based matrix. The paraffin-based matrix includes paraffin and a thermoplastic elastomer, and the second modified boron nitride includes boron nitride modified by an aluminate coupling agent and / or boron nitride modified by a titanate coupling agent.

[0009] Preferably, the thermosetting resin matrix is ​​an epoxy resin matrix, and the mass ratio of the first modified boron nitride to the thermosetting resin matrix is ​​1:1-2.

[0010] Preferably, the heat conducting module is a thin film structure, and the thickness of the heat conducting module is 2 to 3 mm.

[0011] Preferably, the thermoplastic elastomer is styrene-ethylene-butylene-styrene (SEBS); the mass percentage of the thermoplastic elastomer in the paraffin-based matrix is ​​10-18%.

[0012] Preferably, the second modified boron nitride is boron nitride modified by an aluminate coupling agent; the mass percentage of the second modified boron nitride in the paraffin-based composite material is ≤15%.

[0013] Preferably, the phase change module is a fin structure, and the fin structure includes a base and fin units arranged at intervals on the upper surface of the base.

[0014] Preferably, the thickness of the base is 10-20 mm; the height of the fin unit is 30-40 mm, and the thickness is 2-4 mm; and the interval between any two adjacent fin units is 5-7 mm.

[0015] The present invention provides a thermoelectric device enhanced by phase change thermal management, comprising a heat sink and a thermoelectric device, wherein the heat sink is the phase change heat sink described in the above technical solution.

[0016] The present invention provides a method for preparing a thermoelectric device using phase change thermal management enhancement as described in the above technical solution, comprising the following steps:

[0017] A thermal conductive module is prepared at the hot end of the thermoelectric device, and a phase change module is prepared at the cold end of the thermoelectric device to obtain the thermoelectric device enhanced by phase change thermal management; the preparation method of the thermal conductive module and the phase change module is fused deposition 3D printing.

[0018] Preferably, the conditions for preparing the thermal conductive module by fused deposition 3D printing include: a printing temperature of 110 to 120° C., a printing speed of 5 to 10 mm / s, and a curing temperature of 150 to 160° C.;

[0019] The conditions for preparing the phase change module by fused deposition 3D printing include: a printing speed of 5 to 10 mm / s, a barrel temperature of 90 to 100° C., and a nozzle temperature of 100 to 120° C.

[0020] The present invention provides a phase change heat sink, including a heat conduction module and a phase change module, wherein the heat conduction module is arranged at the hot end of the thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device; the material of the heat conduction module is a thermosetting resin-based composite material, wherein the thermosetting resin-based composite material includes a thermosetting resin matrix and a first modified boron nitride dispersed in the thermosetting resin matrix, wherein the first modified boron nitride includes a silane coupling agent modified boron nitride; the material of the phase change module is a paraffin-based composite material, wherein the paraffin-based composite material includes a paraffin-based matrix and a second modified boron nitride dispersed in the paraffin-based matrix, wherein the paraffin-based matrix includes paraffin and a thermoplastic elastomer, wherein the second modified boron nitride includes aluminate coupling agent modified boron nitride and / or titanate coupling agent modified boron nitride. The present invention adopts a heat conduction module of a specific material arranged at the hot end of the thermoelectric device, wherein the heat conduction module has high thermal conductivity and insulation properties, and when the heating element is working, it can ensure that the heat is transferred to the thermoelectric device through the heat conduction module to the maximum extent. At the same time, the present invention uses a phase change module made of a specific material to be set at the cold end of the thermoelectric device. The phase change module has good insulation, thermal stability and excellent heat storage performance. When the heating element stops working, the heat stored in the phase change module can be quickly released through heat exchange, which can enable the thermoelectric device to convert the thermal energy stored in the phase change module into electrical energy again. The present invention selects a heat conductive module and a phase change module made of a specific material, which has a low contact thermal resistance with the thermoelectric device and good heat dissipation performance, and can ensure the temperature difference between the hot and cold ends of the thermoelectric device, thereby enhancing the output performance of the thermoelectric device.

[0021] At the same time, the phase change heat sink provided by the present invention has low density and low cost, and can meet the adaptation requirements of various thermoelectric devices.

[0022] The present invention provides a thermoelectric device enhanced by phase change thermal management, comprising a heat sink and a thermoelectric device, wherein the heat sink is the phase change heat sink described in the above technical solution. The phase change heat sink provided by the present invention has low contact thermal resistance with the thermoelectric device, and the phase change heat sink has good heat dissipation performance, which can effectively enhance the output performance of the thermoelectric device.

[0023] The present invention provides a method for preparing a thermoelectric device enhanced by phase change thermal management as described in the above technical solution, comprising the following steps: preparing a phase change module at the cold end of the thermoelectric device, preparing a thermal conductive module at the hot end of the thermoelectric device, and obtaining the thermoelectric device enhanced by phase change thermal management; the preparation method of the thermal conductive module and the phase change module is fused deposition model (FDM) 3D printing. The present invention uses the FDM 3D printing method to print the thermal conductive module and the phase change module in situ at the hot end and the cold end of the thermoelectric device, respectively, which is conducive to reducing the contact thermal resistance and thus improving the thermal conductivity, ensuring the temperature difference at both ends of the thermoelectric arm of the thermoelectric device, thereby increasing the output performance of the thermoelectric device. At the same time, the materials of the thermal conductive module and the phase change module are in situ printed at both ends of the thermoelectric device by the FDM 3D printing method, ensuring the integration of the thermoelectric device device enhanced by phase change thermal management, and avoiding secondary packaging. Finally, the present invention uses FDM 3D printing to directly obtain the structure of the thermal conductive module and the phase change module, which greatly reduces the cost of mechanical processing and can meet the application environment of various thermoelectric devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the contact angle test result of boron nitride (BN) modified by silane coupling agent (KH550);

[0025] Figure 2 This is the contact angle test result of boron nitride (BN) modified by aluminate coupling agent (ACA);

[0026] Figure 3 A schematic diagram of the decomposed structure of a thermoelectric device enhanced by phase change thermal management provided by the present invention;

[0027] Figure 4 A schematic diagram of the exploded structure of a thermoelectric device enhanced by phase change thermal management provided by the present invention when viewed from the front;

[0028] Figure 5 A curve diagram showing the change of the cold end temperature over time of the thermoelectric device enhanced by phase change thermal management provided in Example 1 and the device product provided in the comparative example;

[0029] Among them: 1 is a phase change module, 2 is an upper substrate, 3 is a p-type thermoelectric arm, 4 is an n-type thermoelectric arm, 5 is a second nickel electrode, 6 is a lower substrate, 7 is a heat conduction module, and 8 is a first nickel electrode. DETAILED DESCRIPTION

[0030] The present invention provides a phase change heat sink, comprising a heat conduction module and a phase change module, wherein the heat conduction module is arranged at the hot end of a thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device;

[0031] The material of the heat conduction module is a thermosetting resin-based composite material, the thermosetting resin-based composite material includes a thermosetting resin matrix and a first modified boron nitride dispersed in the thermosetting resin matrix, and the first modified boron nitride includes a silane coupling agent-modified boron nitride;

[0032] The material of the phase change module is a paraffin-based composite material, which includes a paraffin-based matrix and a second modified boron nitride dispersed in the paraffin-based matrix. The paraffin-based matrix includes paraffin and a thermoplastic elastomer, and the second modified boron nitride includes boron nitride modified by an aluminate coupling agent and / or boron nitride modified by a titanate coupling agent.

[0033] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0034] Combine the following Figure 3 and Figure 4 , the structure of the phase change heat sink provided by the present invention is described in detail.

[0035] The phase change heat sink provided by the present invention includes a heat conduction module 7. The heat conduction module 7 is arranged at the hot end of the thermoelectric device. The heat conduction module 7 is used to conduct the heat generated by the heating element to the thermoelectric device. In the present invention, the material of the heat conduction module 7 is a thermosetting resin-based composite material, and the thermosetting resin-based composite material includes a thermosetting resin matrix and a first modified boron nitride dispersed in the thermosetting resin matrix, and the first modified boron nitride includes a silane coupling agent modified boron nitride. The material of the heat conduction module 7 provided by the present invention is a thermosetting resin-based composite material, which has high thermal conductivity and insulation properties.

[0036] In the present invention, the thermosetting resin matrix is ​​preferably an epoxy resin matrix, which has a relatively low epoxy resin equivalent and molecular weight, and thus has a high glass transition temperature, so that it remains solid at room temperature. As the temperature rises, the intermolecular forces weaken rapidly, forming a low-viscosity liquid.

[0037] In an embodiment of the present invention, the thermosetting epoxy resin used in the epoxy resin matrix is ​​a mixture of epoxy resin E-20 and curing agent dicyandiamide. The softening temperature of E-20 epoxy resin is 79° C. The epoxy value (eq / 100g) is 0.20 to 0.22.

[0038] In the present invention, the preparation method of the silane coupling agent modified boron nitride preferably comprises the following steps:

[0039] Dispersing the boron nitride in a strong alkaline aqueous solution for surface activation treatment to obtain surface activated boron nitride;

[0040] The surface activated boron nitride is dispersed in a silane coupling agent solution for modification to obtain silane coupling agent modified boron nitride.

[0041] The present invention disperses the boron nitride (BN) in a strong alkali aqueous solution for surface activation treatment to obtain surface-activated boron nitride. In the present invention, the boron nitride is specifically a boron nitride powder, and the average particle size of the BN powder is preferably 10 to 15 μm. The strong alkali aqueous solution is preferably an aqueous sodium hydroxide solution, and the molar concentration of the strong alkali aqueous solution is preferably 1 to 4 mol / L. The temperature of the surface activation treatment is preferably room temperature, the time is preferably 3 to 6 hours, and the surface activation treatment is carried out under stirring. After the surface activation treatment technology, the present invention preferably performs solid-liquid separation, water washing and drying on the reaction liquid obtained by the surface activation treatment in sequence to obtain surface-activated boron nitride, and the solid-liquid separation is preferably suction filtration. The present invention preferably performs surface activation treatment on boron nitride by a strong alkali aqueous solution, and can introduce active functional groups such as hydroxyl (-OH) on the surface of boron nitride.

[0042] After obtaining the surface activated boron nitride, the present invention disperses the surface activated boron nitride in a silane coupling agent solution for the first modification to obtain silane coupling agent modified boron nitride. In the present invention, the silane coupling agent solution preferably includes a silane coupling agent and a solvent, and the silane coupling agent is preferably KH550. The solvent is preferably an ethanol aqueous solution, and the mass percentage of ethanol in the ethanol aqueous solution is preferably 95%. The mass of the surface activated boron nitride and the silane coupling agent in the silane coupling agent solution is preferably 50:1-1.5. The temperature of the first modification is preferably 40-60°C, the time is preferably 1-2h, the first modification is carried out under the condition of water bath heating, and the first modification is carried out under stirring. In the present invention, after the first modification is completed, the first modified liquid is obtained. The present invention preferably performs solid-liquid separation and drying on the first modified liquid in sequence to obtain the silane coupling agent modified boron nitride. The solid-liquid separation is preferably suction filtration. The drying temperature is preferably 50-60°C. In the present invention, the modification principle is: the silane coupling agent reacts with the active functional groups (including -OH) on the surface of the surface activated boron nitride to form a chemical bond; at the same time, the silane coupling agent is adsorbed on the surface of the surface activated boron nitride through physical adsorption.

[0043] The present invention preferably sequentially performs surface active treatment and silane coupling agent modification on the boron nitride to obtain silane coupling agent modified boron nitride, which can effectively improve the hydrophobicity of the boron nitride, thereby effectively avoiding the agglomeration phenomenon of the silane coupling agent modified boron nitride when dispersed in the thermosetting resin, thereby improving the thermal conductivity of the thermosetting resin-based composite material.

[0044] In the present invention, the mass ratio of the first modified boron nitride to the thermosetting resin matrix is ​​preferably 1:1-2.

[0045] In the present invention, the preparation method of the thermosetting resin-based composite material preferably comprises the following steps: mixing the first modified boron nitride and the thermosetting resin at 80°C with high-speed stirring to obtain the thermosetting resin-based composite material, wherein the high-speed stirring speed is preferably 400 to 600 rpm. In the present invention, during the mixing, the first modified boron nitride is preferably added to the thermosetting resin in small amounts for multiple times. The specific implementation of the mixing is preferably vacuum blending.

[0046] In the present invention, the heat conduction module 7 is preferably a thin film structure, and the thickness of the heat conduction module 7 is preferably 2-3 mm. In an embodiment of the present invention, the size of the heat conduction module 7 is 40 mm×40 mm×3 mm.

[0047] The phase change heat sink provided by the present invention includes a phase change module 1. The phase change module 1 is arranged at the cold end of the thermoelectric device. The phase change module 1 has the properties of insulation, good thermal stability and excellent heat storage. When the heating element stops working, the phase change module 1 can act as a heat source to release the stored heat again and conduct it to the thermoelectric device, which further converts the thermal energy into electrical energy. In the present invention, the material of the phase change module 1 is a paraffin-based composite material, which includes a paraffin-based matrix and a second modified boron nitride dispersed in the paraffin-based matrix, the paraffin-based matrix includes paraffin (PW) and a thermoplastic elastomer, and the second modified boron nitride includes boron nitride modified by an aluminate coupling agent and / or boron nitride modified by a titanate coupling agent.

[0048] In the present invention, the thermoplastic elastomer is preferably styrene-ethylene-butylene-styrene (SEBS). The mass percentage of the thermoplastic elastomer in the paraffin-based matrix is ​​preferably 10-18%, more preferably 10-16%, further preferably 12-15%, and specifically 15.8% in the embodiment. In the present invention, the role of the thermoplastic elastomer in the paraffin-based composite material is to form a reversible physical gel with paraffin, thereby organizing the free flow of paraffin after melting, ensuring that the paraffin-based composite material can maintain shape stability under high temperature conditions, thereby preventing and controlling paraffin leakage in the paraffin-based composite material. The mass percentage of the thermoplastic elastomer in the paraffin-based matrix should not be too large or too small. Too large will cause the paraffin-based composite material to have poor fluidity during FDM 3D printing, and it is easy to clog the printing nozzle; too small will result in the inability to form enough reversible physical gel, which is easy to cause the paraffin in the paraffin-based composite material to leak under high temperature conditions.

[0049] In the present invention, the second modified boron nitride is preferably aluminate coupling agent (ACA) modified boron nitride. The mass percentage of the second modified boron nitride in the paraffin-based composite material is preferably ≤15%, more preferably 5-15%, further preferably 10-15%, most preferably 13-15%, and the embodiment can be 14.9%. In the present invention, the preparation method of the aluminate coupling agent modified boron nitride preferably includes the following steps: dispersing the boron nitride in an aluminate coupling agent solution for a second modification to obtain aluminate coupling agent modified boron nitride. In the present invention, the boron nitride is preferably boron nitride powder. The average particle size of the BN powder is preferably 10-15 μm. The aluminate coupling agent solution preferably includes an aluminate coupling agent and a solvent. The solvent is preferably anhydrous ethanol. The mass of the aluminate coupling agent in the boron nitride and the aluminate coupling agent solution is preferably 50:0.5-1. The temperature of the second modification is preferably room temperature, the time is preferably 8-12 hours, and the second modification is carried out under stirring. In the present invention, after the second modification is completed, a second modified liquid is obtained. In the present invention, the second modified liquid is preferably subjected to solid-liquid separation and drying in sequence to obtain the aluminate coupling agent modified boron nitride. The solid-liquid separation is preferably suction filtration. The drying temperature is preferably 50-60°C. The present invention obtains a second modified boron nitride by modifying boron nitride, which can improve the dispersibility of the second modified boron nitride in the paraffin-based matrix, avoid agglomeration of the second modified boron nitride, and thus improve the thermal conductivity of the paraffin-based composite material. In the present invention, the mass percentage of the second modified boron nitride in the paraffin-based composite material cannot be too large or too small. If it is too small, a paraffin-based composite material with excellent thermal conductivity cannot be obtained. If it is too large, the viscosity of the paraffin-based composite material is too large. When the mass percentage of the second modified boron nitride in the paraffin-based composite material is 20%, the paraffin-based composite material is difficult to flow even under high pressure, affecting the FDM 3D printing effect.

[0050] In the present invention, the preparation method of the paraffin-based composite material preferably comprises the following steps: mixing the thermoplastic elastomer and paraffin to obtain a paraffin-based matrix; mixing the second modified boron nitride and the paraffin-based matrix to obtain the paraffin-based composite material. The premixing temperature is preferably 80 to 90°C, the time is preferably 1 to 3 hours, and the premixing is performed under stirring. The mixing temperature is preferably 95 to 100°C, the time is preferably 1 to 4 hours, and the mixing is performed under stirring.

[0051] In the present invention, the phase change enthalpy value of the phase change module 7 is preferably 123 J / g.

[0052] In the present invention, the phase change module 7 is preferably a fin structure, and the fin structure preferably includes a substrate and fin units arranged at intervals on the upper surface of the substrate. The substrate and the fin units arranged at intervals on the upper surface of the substrate are an integrated structure. In the present invention, the thickness of the substrate is preferably 10 to 20 mm; the height of the fin unit is preferably 30 to 40 mm, which can be 30 mm in the embodiment, and the thickness is preferably 2 to 4 mm, which can be 3.2 mm in the embodiment; the spacing distance between any two adjacent fin units is preferably 5 to 7 mm, which can be 6 mm in the embodiment. In a specific embodiment of the present invention, the size of the fin unit is 40 mm × 3.2 mm × 30 mm. The size of the fin structure is 40 mm × 40 mm × 50 mm, the thickness of the substrate in the fin structure is 20 mm, and five groups of fin structure units are arranged on the upper surface of the substrate, and the spacing distance between adjacent fin structure units is 6 mm.

[0053] The present invention provides a thermoelectric device enhanced by phase change thermal management, comprising a heat sink and a thermoelectric device, wherein the heat sink is the phase change heat sink described in the above technical solution.

[0054] Figure 3 A schematic diagram of the exploded structure of a thermoelectric device enhanced by phase change thermal management provided by the present invention. Figure 4 This is a schematic diagram of the exploded structure of the thermoelectric device enhanced by phase change thermal management provided by the present invention when viewed from the front. Figure 3 and Figure 4 , the structure of the thermoelectric device enhanced by phase change thermal management provided by the present invention is described in detail.

[0055] The thermoelectric device enhanced by phase change thermal management provided by the present invention includes a heat sink, and the heat sink is the phase change heat sink described in the above technical solution. The thermal conductive module 7 of the phase change heat sink is arranged at the hot end of the thermoelectric device, and the phase change module 1 of the phase change heat sink is arranged at the cold end of the thermoelectric device. That is, the thermal conductive module 1 of the phase change heat sink is arranged on the lower surface of the lower substrate 6 of the thermoelectric device, and the upper surface of the thermal conductive module 1 of the phase change heat sink is in contact with the lower surface of the lower substrate 6 of the thermoelectric device. The phase change module 7 of the phase change heat sink is arranged on the upper surface of the upper substrate 2 of the thermoelectric device, and the base of the phase change module 7 of the phase change heat sink is in contact with the upper surface of the upper substrate 2 of the thermoelectric device.

[0056] The thermoelectric device enhanced by phase change thermal management provided by the present invention includes a thermoelectric device. In an embodiment of the present invention, the shape of the thermoelectric device is square, and the size of the thermoelectric device is 40 mm×40 mm.

[0057] The thermoelectric device comprises an upper substrate 2 and a lower substrate 6 which are arranged opposite to each other. The upper substrate 2 is a ceramic alumina substrate. The lower substrate 6 is a ceramic alumina substrate. The thermoelectric device comprises a p-type thermoelectric arm 3 and an n-type thermoelectric arm 4 which are arranged between the upper substrate 2 and the lower substrate 6. The p-type thermoelectric arm 3 and the n-type thermoelectric arm 4 exist in pairs, and there are 127 pairs of the p-type thermoelectric arm 3 and the n-type thermoelectric arm 4 between the upper substrate 2 and the lower substrate 6. The center distance between the p-type thermoelectric arm 3 and the n-type thermoelectric arm 4 is 2 mm. The material of the p-type thermoelectric arm 3 and the n-type thermoelectric arm 4 is preferably Bi2Te3. A first nickel electrode 8 is arranged on the lower surface of the upper substrate 2, and the first nickel electrode 8 is fixedly connected to one end of the p-type thermoelectric arm 3 and the n-type thermoelectric arm 4. A plurality of second nickel electrodes 5 are arranged on the upper surface of the lower substrate 6, and the second nickel electrodes 5 are fixedly connected to the other end of the p-type thermoelectric arm 3 and the n-type thermoelectric arm 4. The p-type thermoelectric arm 3 and the n-type thermoelectric arm 4 are electrically interconnected through the first nickel electrode 8 and the second nickel electrode 5 .

[0058] The present invention provides a method for preparing a thermoelectric device using phase change thermal management enhancement as described in the above technical solution, comprising the following steps:

[0059] A thermal conductive module is prepared at the hot end of the thermoelectric device, and a phase change module is prepared at the cold end of the thermoelectric device to obtain the thermoelectric device enhanced by phase change thermal management; the preparation method of the thermal conductive module and the phase change module is fused deposition 3D printing.

[0060] In the present invention, the conditions for preparing the fused deposition 3D printing of the thermal conductive module 7 preferably include: the printing temperature is preferably 110-120°C, and can be 120°C in the embodiment; the printing speed is preferably 5-10 mm / s, and can be 10 mm / s in the embodiment; the curing temperature is preferably 150-160°C, and can be 160°C in the embodiment, and the curing time is preferably 1-2h, and can be 2h in the embodiment.

[0061] In the present invention, the conditions for fused deposition 3D printing for preparing the phase change module 1 preferably include: the printing speed is preferably 5-10 mm / s, the barrel temperature is preferably 90-100° C., and the nozzle temperature is preferably 100-120° C.

[0062] In the present invention, the temperature of the substrate during printing is preferably 55 to 60°C.

[0063] The present invention uses a fused deposition 3D printing method to print a phase change heat sink in situ onto the cold and hot ends of a thermoelectric device, thereby reducing the contact thermal resistance between interfaces and meeting the adaptation requirements of a variety of thermoelectric devices. The thermoelectric device enhanced by phase change thermal management prepared by the present invention has the characteristics of low cost, low density and low contact thermal resistance. Its phase change heat sink has good heat dissipation performance, which can ensure the temperature difference between the cold and hot ends of the thermoelectric device and thus enhance the output performance of the thermoelectric device.

[0064] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0065] Example 1

[0066] This embodiment provides a thermoelectric device using phase change thermal management enhancement. The schematic diagram of the decomposed structure of the thermoelectric device using phase change thermal management enhancement provided by this embodiment is as follows: Figure 3 As shown, the schematic diagram of the decomposed structure of the thermoelectric device enhanced by phase change thermal management provided by this embodiment when viewed from the front is as shown in Figure 4 As shown. This embodiment provides a thermoelectric device enhanced by phase change thermal management, including a phase change heat sink and a thermoelectric device, the phase change heat sink includes a heat conduction module and a phase change module, the heat conduction module is arranged at the hot end of the thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device. In this embodiment, the thermoelectric device is square, and the p-type thermoelectric arm and the n-type thermoelectric arm are both made of Bi2Te3. The size of the thermoelectric device is 40mm×40mm. In this embodiment, the thermoelectric device is composed of 127 pairs of pn-type thermoelectric arms, and the distance between the center of the p-type thermoelectric arm and the center of the n-type thermoelectric arm is 2mm. In this embodiment, the upper and lower substrates of the thermoelectric device are alumina ceramic substrates. The p-type thermoelectric arm and the n-type thermoelectric arm are electrically interconnected through nickel electrodes on the upper and lower ceramic substrates.

[0067] Wherein: the preparation method of the thermal conductive module specifically includes:

[0068] First, pour BN powder (average particle size of 10 μm) into a sodium hydroxide solution with a concentration of 4 mol / L, mechanically stir for 5 hours at room temperature to complete the surface active treatment, and obtain surface activated boron nitride after filtration, washing and drying. Then take 1.5g KH550 and dissolve it in a 95wt% ethanol aqueous solution, stir for 6 hours at room temperature to dissolve, add 50g surface activated boron nitride, stir for 2 hours in a 60℃ water bath to complete the reaction, and obtain KH550 modified boron nitride powder by filtration and drying (60℃). Figure 1The water contact angle test of BN powder before modification and KH550 modified BN powder is shown. The BN powder before modification and KH550 modified BN powder are pressed into discs at a pressure of 10MPa by a tablet press. The disc size is 2cm in diameter and 5mm in thickness. Water droplets are dropped into the discs to observe the angle change (contact angle increases). Figure 1 The left picture shows the water drop contact angle of BN powder before modification after tableting. Figure 1 The right figure shows the water drop contact angle of KH550 modified BN powder after tableting. Figure 1 It can be seen that after modification with KH550, the hydrophobicity of boron nitride powder is enhanced, which can effectively avoid the agglomeration of BN powder when blended with epoxy resin to prepare composite materials.

[0069] 25 g of KH550 modified BN powder and 25 g of epoxy resin were mixed uniformly at a mass ratio of 1:1 at 80° C. with high-speed stirring, wherein boron nitride was added to the epoxy resin in small batches and multiple times, and the epoxy resin-based composite material was obtained after mixing.

[0070] The epoxy resin-based composite material was placed in a glass cylinder and printed onto the hot end of the thermoelectric device on a substrate at 60°C using the FDM 3D printing method. The thermal conductive module was cured at 160°C for 2 hours. The thermal conductive module was a thin film structure, and the printed size of the thermal conductive module was 40mm×40mm×3mm.

[0071] The preparation method of the phase change module specifically includes:

[0072] Take 0.5g of aluminate coupling agent (ACA) and dissolve it in 500mL of anhydrous ethanol, and stir it mechanically at room temperature for 48h until ACA is completely dissolved to obtain ACA solution. Then pour 50g of boron nitride powder (average particle size of 10μm) into the ACA solution, stir it mechanically at room temperature for 8h, and then filter and dry (60℃) to obtain aluminate coupling agent modified boron nitride (ACA modified BN). Figure 2 The water contact angle test of BN powder before modification and ACA modified BN powder is shown. The BN powder before modification and ACA modified BN powder are pressed into discs at a pressure of 10MPa by a tablet press. The disc size is 2cm in diameter and 5mm in thickness. Water droplets are dropped into the discs to observe the change in angle (the result is that the contact angle increases). Figure 2 The left picture shows the water drop contact angle of BN powder before modification after tableting. Figure 2 The right figure in the figure shows the water drop contact angle of ACA modified BN powder after tableting. Figure 2 It can be seen that after ACA modification, the hydrophobicity of boron nitride powder is significantly enhanced, which can effectively avoid the agglomeration of BN powder when blended with paraffin and SEBS to prepare paraffin-based composites.

[0073] First, paraffin wax (PW) is dissolved at 90°C, and then styrene-ethylene-butylene-styrene (SEBS) is added to the paraffin wax in small amounts several times and stirred for 3 hours to be evenly dispersed to obtain a paraffin-based matrix; finally, ACA-modified BN powder is added to the paraffin-based matrix, and stirred at 100°C for 4 hours to achieve homogenization to obtain a paraffin-based composite material. In the paraffin-based composite material, the mass ratio of ACA-modified BN powder, SEBS and PW is 1:0.9:4.8, of which the ACA-modified BN powder accounts for 14.9% of the mass of the paraffin-based composite material.

[0074] The prepared paraffin-based composite material was cut into small pieces and placed in a glass barrel. The FDM 3D printing method was used to print the cold end of the thermoelectric device on a substrate at 60°C to obtain a phase change module. The phase change module is a fin structure, which includes a substrate and fin units arranged on the upper surface of the substrate at intervals. The overall size of the phase change module is 40mm×40mm×50mm, consisting of five fins, the thickness of the substrate is 20mm, the size of the fin unit is 40mm×3.2mm×30mm, and the distance between the fin units is 6mm.

[0075] The phase change enthalpy value of the phase change module prepared in this embodiment is 123 J / g.

[0076] The printing speed of the phase change module is 5 mm / s, the barrel temperature is 90°C, and the nozzle temperature is 100°C.

[0077] Example 2

[0078] The preparation method is basically the same as that in the embodiment, except that the printing speed of the phase change module is 10 mm / s, the barrel temperature is 100° C., and the nozzle temperature is 120° C.

[0079] Comparative Example 1

[0080] This comparative example provides a thermoelectric device enhanced by phase change thermal management. This comparative example provides a thermoelectric device enhanced by phase change thermal management, including a thermal conductive module and a thermoelectric device, wherein the thermal conductive module is arranged at the hot end of the thermoelectric device. The thermoelectric device in this comparative example is square, and both the p-type thermoelectric arm and the n-type thermoelectric arm are made of Bi2Te3. The size of the thermoelectric device is 40mm×40mm. The thermoelectric device in this comparative example is composed of 127 pairs of pn-type thermoelectric arms, and the distance between the center of the p-type thermoelectric arm and the center of the n-type thermoelectric arm is 2mm. The upper and lower substrates of the thermoelectric device in this comparative example are alumina ceramic substrates. The p-type thermoelectric arm and the n-type thermoelectric arm are electrically interconnected through nickel electrodes on the upper and lower ceramic substrates.

[0081] Wherein: the preparation method of the thermal conductive module specifically includes:

[0082] First, pour BN powder into a sodium hydroxide solution with a concentration of 4 mol / L, mechanically stir at room temperature for 5 hours to complete the surface active treatment, and obtain surface activated boron nitride after suction filtration, washing and drying. Then take 1.5g KH550 and dissolve it in a 95wt% ethanol aqueous solution, stir at room temperature for 6 hours to dissolve, add 50g surface activated boron nitride, stir in a 60℃ water bath for 2 hours to complete the reaction, and obtain KH550 modified boron nitride powder by suction filtration and drying (60℃).

[0083] 25 g of KH550 modified BN powder and 25 g of epoxy resin were mixed at a mass ratio of 1:1 at 90° C. for 6 h at high speed stirring, wherein boron nitride was added to the epoxy resin in small batches and multiple times, and an epoxy resin-based composite material was obtained after mixing.

[0084] The epoxy resin-based composite material was placed in a glass cylinder and printed onto the hot end of the thermoelectric device on a substrate at 60°C using the FDM 3D printing method. The thermal conductive module was cured at 160°C for 2 hours. The thermal conductive module was a thin film structure, and the printed size of the thermal conductive module was 40mm×40mm×3mm.

[0085] Test Case

[0086] In order to demonstrate the effect of phase change heat sink on the output performance of thermoelectric devices, the thermoelectric devices enhanced by phase change thermal management prepared in Example 1 and Comparative Example 1 were placed on a heating table at 130°C at the same time, and the thermocouple was glued to the cold end of the thermoelectric device with glue, and the temperature changes of the two were constantly monitored by a TASi temperature detector.

[0087] Figure 5 The cold end temperature of the thermoelectric device enhanced by phase change thermal management prepared in Example 1 and Comparative Example 1 changes with time. Figure 5 It can be seen that compared with the thermoelectric devices enhanced by phase change thermal management prepared in Example 1 and Comparative Example 1, there is a temperature difference of about 50°C between the two, indicating that the thermoelectric device enhanced by phase change thermal management prepared in Example 1 can effectively reduce the temperature of the cold end of the thermoelectric device to increase the temperature difference, thereby enhancing the power output of the thermoelectric device itself.

[0088] From the above embodiments, it can be seen that the present invention provides a method for preparing a thermoelectric device enhanced by phase change thermal management. The present invention uses a molten deposition 3D printing method to print a phase change heat sink in situ to the cold end and hot end of the thermoelectric device, thereby reducing the contact thermal resistance between the interfaces and meeting the adaptation requirements of various thermoelectric devices. The thermoelectric device enhanced by phase change thermal management prepared by the present invention has the characteristics of low cost, low density and low contact thermal resistance. Its phase change heat sink has good heat dissipation performance, which can ensure the temperature difference between the cold and hot ends of the thermoelectric device and thus enhance the output performance of the thermoelectric device.

[0089] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A phase change heat sink, characterized in that: It includes a heat conduction module and a phase change module, wherein the heat conduction module is arranged at the hot end of the thermoelectric device, and the phase change module is arranged at the cold end of the thermoelectric device; The material of the heat conduction module is a thermosetting resin-based composite material, the thermosetting resin-based composite material includes a thermosetting resin matrix and a first modified boron nitride dispersed in the thermosetting resin matrix, and the first modified boron nitride includes a silane coupling agent-modified boron nitride; The material of the phase change module is a paraffin-based composite material, which includes a paraffin-based matrix and a second modified boron nitride dispersed in the paraffin-based matrix. The paraffin-based matrix includes paraffin and a thermoplastic elastomer, and the second modified boron nitride includes boron nitride modified by an aluminate coupling agent and / or boron nitride modified by a titanate coupling agent.

2. The phase change heat sink according to claim 1, characterized in that: The thermosetting resin matrix is ​​an epoxy resin matrix, and the mass ratio of the first modified boron nitride to the thermosetting resin matrix is ​​1:1-2.

3. The phase change heat sink according to claim 1 or 2, characterized in that: The heat conduction module is a thin film structure, and the thickness of the heat conduction module is 2 to 3 mm.

4. The phase change heat sink according to claim 1, characterized in that: The thermoplastic elastomer is styrene-ethylene-butylene-styrene; the mass percentage of the thermoplastic elastomer in the paraffin-based matrix is ​​10-18%.

5. The phase change heat sink according to claim 1, characterized in that: The second modified boron nitride is boron nitride modified by an aluminate coupling agent; the mass percentage of the second modified boron nitride in the paraffin-based composite material is ≤15%.

6. The phase change heat sink according to claim 1, 4 or 5, characterized in that: The phase change module is a fin structure, and the fin structure includes a base and fin units arranged at intervals on the upper surface of the base.

7. The phase change heat sink according to claim 6, characterized in that: The thickness of the base is 10-20 mm; the height of the fin unit is 30-40 mm, and the thickness is 2-4 mm; and the interval between any two adjacent fin units is 5-7 mm.

8. A thermoelectric device utilizing phase change thermal management enhancement, characterized in that: It comprises a heat sink and a thermoelectric device, wherein the heat sink is the phase change heat sink according to any one of claims 1 to 7.

9. The method for preparing a thermoelectric device using phase change thermal management enhancement according to claim 8, characterized in that: The following steps are involved: A thermal conductive module is prepared at the hot end of the thermoelectric device, and a phase change module is prepared at the cold end of the thermoelectric device to obtain the thermoelectric device enhanced by phase change thermal management; the preparation method of the thermal conductive module and the phase change module is fused deposition 3D printing.

10. The preparation method according to claim 9, characterized in that: The conditions for preparing the thermal conductive module by fused deposition 3D printing include: a printing temperature of 110 to 120° C., a printing speed of 5 to 10 mm / s, and a curing temperature of 150 to 160° C.; The conditions for preparing the phase change module by fused deposition 3D printing include: a printing speed of 5 to 10 mm / s, a barrel temperature of 90 to 100° C., and a nozzle temperature of 100 to 120° C.

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