Aluminum-based all-solid-state phase change radiator for passive heat dissipation of TEC and preparation method of aluminum-based all-solid-state phase change radiator

Abstract

The invention discloses an aluminum-based all-solid-state phase change radiator for passive heat dissipation of a TEC and a preparation method of the aluminum-based all-solid-state phase change radiator and belongs to the field of heat dissipation materials and technology application. Comprising an aluminum-based heat sink layer, an oxidation modification layer and a high-thermal-conductivity insulating phase change layer which are sequentially stacked from bottom to top, and heat dissipation teeth for increasing the heat exchange area are evenly distributed on the surface of the aluminum-based heat sink layer; the oxidation modification layer grows on the surface of the aluminum-based heat sink layer in an anodic oxidation mode so as to enhance surface energy and interlayer adhesion; the high-thermal-conductivity insulating phase change layer is uniformly coated above the oxidation modification layer in a numerical control dispensing manner and then is cured and formed, and main materials of the high-thermal-conductivity insulating phase change layer are phase change microcapsules, an insulating heat-conducting medium and a thermosetting elastic matrix body. The aluminum-based all-solid-state phase change radiator is simple in preparation method, free of leakage risk of the phase change material and excellent in heat conduction, heat storage and heat dissipation capacity and electrical insulation performance, and compared with a traditional TEC passive radiator, the heat exchange efficiency and the use safety are remarkably improved, so that the aluminum-based all-solid-state phase change radiator has wide application prospects in the field of TEC heat management.

Description

Technical Field

[0001] The invention belongs to the field of heat dissipation materials and technology applications, and relates to an aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation and a preparation method thereof. Background Art

[0002] Semiconductor refrigeration chips (TECs) are widely used in many fields such as electronics, automobiles, lighting, optoelectronic devices and medical treatment. However, TECs generate a lot of heat during operation, and excessively high temperatures will shorten the life of semiconductor devices, because the increase in temperature will lead to a decrease in electron mobility in the device, a decrease in the generation of electron-hole pairs, and an increase in lattice defects in the material, which will lead to a decrease in the overall performance of the device or even failure. Therefore, thermal management is crucial to maintaining the stability and performance of TECs. It can effectively reduce the operating temperature of the device, extend the service life of the device, and reduce the frequency of equipment maintenance and replacement, thereby ensuring its normal operation and maximizing its performance. However, at present, the heat dissipation method of TEC usually relies on active heat dissipation devices such as air cooling and water cooling, which are large in size and weight, and have high additional energy consumption, resulting in a decrease in the energy efficiency ratio of TEC and limited usage scenarios. Although the traditional passive heat dissipation method relying on natural convection and thermal radiation does not require additional energy consumption and space, due to the large and continuous heat generation of TEC, conventional passive heat dissipation methods usually cannot meet the needs of its normal operation. Therefore, in order to achieve a high energy efficiency ratio and miniaturized heat dissipation solution for TEC, it is key to develop a new type of radiator that can assist its passive heat dissipation.

[0003] Phase change material is a kind of energy storage material with special thermal properties. It can undergo phase change within a specific temperature range, thereby absorbing or releasing a large amount of heat. It has been widely used in the fields of thermal energy storage, temperature regulation, etc. Since phase change materials can significantly improve the heat storage capacity of heat sinks, they are more suitable for assisting in enhancing the passive heat dissipation effect of radiators. At present, most common phase change passive radiators use heat pipes to encapsulate solid-liquid phase change materials, and heat transfer is achieved through the solid-liquid phase change of phase change materials inside the heat pipes. However, after the phase change of traditional solid-liquid phase change radiators, the internal phase change materials will produce flow slippage, resulting in a shift in contact with the heat source, reducing the uniformity of heat absorption, and the thermal conductivity of traditional solid-liquid phase change materials is relatively poor, resulting in low heat dissipation efficiency, especially in high-power and high-temperature application scenarios. At the same time, when subjected to external forces, traditional solid-liquid phase change radiators also have the risk of phase change material leakage.

[0004] Therefore, if the constrained composite phase change material is combined with a passive heat dissipation substrate and the thermal conductivity of the composite phase change material is improved to form a fully solid-state phase change heat sink, the safety of use and heat exchange capacity of the passive heat sink can be significantly enhanced.

[0005] A common method for preparing a constrained composite phase change material is to use a porous material as a template and inject a mixture of a phase change material and a high thermal conductivity material into the template to obtain the composite phase change material. This structure can improve the thermal conductivity of the composite material and has a certain shaping performance. However, since porous materials are generally powder materials, although the prepared shaped composite phase change material does not have the problem of liquid leakage, it has the defects of poor contact with the heat source and easy fragmentation when impacted. Therefore, this method is difficult to be used for assisting TEC passive heat dissipation.

[0006] Another mainstream method for preparing a shaped composite phase change material is to composite the phase change material with a polymer substrate. Compared with powder materials such as porous templates, the shaped material prepared from the polymer substrate also does not have the problem of liquid leakage, and its mechanical properties and impact resistance are greatly improved, which can endow the composite phase change material with good flexibility, tensile resistance and elasticity. CN201910951534.5 discloses a preparation method of a paraffin-SEBS thermoplastic elastomer composite phase change material. The flexible composite phase change material prepared by this method has strong adsorption capacity, close fit with the heat source, large phase change enthalpy value and strong heat storage capacity.

[0007] However, polymer-based composite phase change materials generally have extremely low thermal conductivity and poor heat exchange performance. In order to improve the thermal conductivity of polymer matrix composite phase change materials, CN111607362A and CN110137626A disclose two kinds of flexible high thermal conductivity phase change materials applied to thermal management. However, due to the incorporation of metal thermal media, the phase change materials prepared by the two methods do not have electrical insulation, and the application of such phase change materials to TEC thermal management will increase the risk of device short circuit and fire. Summary of the Invention

[0008] In order to solve the problems of large volume and high additional energy consumption existing in traditional TEC active radiators, and low heat exchange efficiency, slow heat dissipation, and easy leakage of phase change materials existing in traditional passive phase change radiators, the present invention provides an aluminum-based all-solid-state phase change radiator for TEC passive heat dissipation and its preparation method. An oxidation modification layer is prepared on the surface of the aluminum-based heat sink to improve the surface energy and interlayer adhesion. The constrained high thermal conductivity insulating phase change material is introduced through a numerical control dispensing technology, without complex processing methods, maximizing the use of the heat exchange area of the aluminum-based heat sink layer, improving the heat conduction efficiency, and significantly enhancing the heat dissipation capacity of the passive phase change radiator.

[0009] The aluminum-based all-solid-state phase change radiator of the present invention has the following characteristics: simple preparation method, no risk of phase change material leakage, excellent heat conduction-heat storage-heat dissipation ability and electrical insulation performance. Compared with traditional TEC passive phase change radiators, the heat exchange efficiency and use safety are significantly improved, and it has broad application prospects in the field of TEC thermal management.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] An aluminum-based all-solid-phase change radiator for passive heat dissipation of TEC. The aluminum-based all-solid-phase change radiator includes an aluminum-based heat sink layer, an oxidation modification layer, and a high thermal conductivity insulating phase change layer that are stacked in sequence from bottom to top. The surface of the aluminum-based heat sink layer is evenly distributed with heat dissipation teeth for increasing the heat exchange area; the oxidation modification layer is grown on the surface of the aluminum-based heat sink layer by an anodic oxidation method to enhance surface energy and interlayer adhesion; the high thermal conductivity insulating phase change layer is evenly coated above the oxidation modification layer by a numerical control dispensing method and then cured into shape. Its main materials are phase change microcapsules, insulating thermal conductive media, and thermosetting elastic matrix bodies.

[0012] Further, the heat dissipation teeth on the surface of the aluminum-based heat sink can be cylinders, cuboids, or any other shape;

[0013] Further, the high thermal conductivity insulating phase change layer (this layer is uniform, and the phase change component, thermal conductive medium, and elastic matrix are uniformly mixed and then cured) is prepared by uniformly mixing the following components by mass percentage: 5-10% phase change component, 75-85% thermosetting elastic matrix body, 10-15% insulating thermal conductive medium, and the sum of the three is 100%; among them, the phase change component is formed into phase change microcapsules wrapped by a microcapsule wall; the thermal conductivity of the high thermal conductivity insulating phase change layer is higher than 1W / m·K, and the resistivity is greater than 15000Ω·m.

[0014] Preferably, the phase change component includes but is not limited to: one or more of paraffin microcapsules and octadecane microcapsules.

[0015] Preferably, the phase change microcapsules have a core-shell structure, a particle size of 5-10um, a phase change temperature of 5-45°C, and an enthalpy value higher than 120kJ / kg. Further, the wall material of the phase change microcapsules is one or more combinations of inorganic substances and polymers. Among them, the inorganic substances include silicon dioxide, titanium dioxide, aluminum oxide, etc., and the polymers include polyurethane, polymethyl methacrylate, etc. The wall material of the phase change microcapsules internally wraps any one of paraffin and octadecane, that is, the substance inside the shell is a uniform phase change component.

[0016] Preferably, the thermosetting elastic matrix body includes but is not limited to: one or more of polydimethylsiloxane (PDMS), fluororubber, polyurethane, and polyacrylate;

[0017] Preferably, the insulating thermal conductive medium includes but is not limited to: one or more of aluminum nitride, boron nitride, zirconium oxide, and aluminum oxide.

[0018] Further, the total thickness of the aluminum-based heat sink layer is 3-5mm, the thickness of the oxidation modification layer is 23-25um, and the thickness of the high thermal conductivity insulating phase change layer is 1-3mm.

[0019] The preparation method of the above-mentioned aluminum-based all-solid phase change radiator for passive heat dissipation of TEC includes the following steps:

[0020] Step (1) Prepare the anodic oxidation modified layer: First, use an alkaline cleaning agent or solvent to remove the oil, dust and oxides on the surface of the aluminum-based heat sink layer, and then put the aluminum-based heat sink into an electrolytic cell filled with sulfuric acid solution and conduct anodic oxidation by applying electricity to obtain an oxidation modified layer with a thickness of 23-25 μm. The heat dissipation teeth are evenly distributed on the surface of the aluminum-based heat sink layer.

[0021] Preferably, the mass concentration of the sulfuric acid solution is 15% to 20%.

[0022] Preferably, during the anodic oxidation process, a pulsed current oxidation power supply is used, the voltage is 20-120V, the anodic oxidation pulse frequency is 2kHz-30kHz, the duty cycle of the anodic oxidation is 6%-30%, the oxidation temperature is 0-25°C, and the oxidation time is 20-80 minutes.

[0023] Step (2) Configure the phase change material precursor: First, add the phase change component and the insulating and heat-conducting medium, and then add the thermosetting elastic matrix for preliminary mixing; centrifuge and stir the obtained mixed material in a self-rotating and revolving centrifuge to mix and defoam it sufficiently to obtain a coatable thermally conductive and insulating phase change material precursor.

[0024] Preferably, the centrifugal stirring speed in step (2) is 800-2000 rpm, and the stirring time is 10-15 minutes.

[0025] Step (3) Numerically controlled dispensing coating and curing: Uniformly coat the coatable thermally conductive and insulating phase change material precursor obtained in step (2) on the surfaces of the heat dissipation teeth of the aluminum-based heat sink layer prepared with the anodic oxidation modified layer in step (1), and cure to form a stable and tightly fitting state.

[0026] Preferably, the coating method is numerically controlled dispensing coating.

[0027] Preferably, the mass density of the numerically controlled dispensing coated phase change material is 0.2-0.5 g / cm 2 .

[0028] Preferably, the numerically controlled dispensing coating speed is 10-15 cm / s.

[0029] Preferably, the nozzle size of the numerically controlled dispensing coating is 30-35G.

[0030] Preferably, the dispensing pressure of the numerically controlled dispensing coating is 350-450 kPa.

[0031] Preferably, the curing temperature is 23 - 25°C, the curing time is 20 - 24 h; or the curing temperature is 90 - 150°C, and the curing time is 0.25 - 1.5 h.

[0032] The beneficial effects of the present invention are as follows:

[0033] (1) The aluminum-based all-solid-state phase change heat sink prepared by the present invention can effectively alleviate the heat accumulation of the aluminum-based heat sink layer and delay the temperature rise by introducing high thermal conductivity, electrically insulating, and all-solid-state phase change materials. At the same time, the radiation heat dissipation efficiency enhanced by its high thermal conductivity characteristics can greatly improve the heat conduction and heat dissipation effect of the composite heat sink, and significantly alleviate the temperature rise of the heat source. The preparation and use methods are simple, there is no leakage risk, no additional encapsulation is required, and it can be used to assist in realizing the efficient passive heat dissipation of the TEC;

[0034] (2) During the preparation process of the present invention, by introducing the numerical control dispensing coating technology, the thermally conductive and insulating phase change layer can be evenly and tightly attached to the surface of the heat dissipation teeth of any shaped aluminum-based heat sink layer, including cylinders, cuboids, wedges, etc. The coating process is convenient, has high repeatability, saves raw materials and reduces costs. There is no need to prepare a phase change material frame in advance, which is conducive to the rapid integration and assembly of the TEC and the heat dissipation module;

[0035] (3) Compared with traditional TEC heat sinks, the present invention does not require additional air-cooling or water-cooling devices, and at the same time has high resistivity, good insulation performance, and no risk of phase change material leakage. Even when it comes into contact with the TEC electrode or is damaged by external forces during use, there is no risk of short circuit and fire. Description of the Drawings

[0036] Figure 1 is the preparation flow chart of the aluminum-based all-solid-state phase change heat sink of the present invention;

[0037] Figure 2 is the schematic diagram of the numerical control dispensing coating method for preparing the high thermally conductive and insulating phase change material layer of the present invention;

[0038] Figure 3 is the schematic cross-sectional view of the assembly method of the aluminum-based all-solid-state phase change heat sink of the present invention applied to TEC heat dissipation;

[0039] Figure 4 is the effect comparison diagram of the aluminum-based all-solid-state phase change heat sinks of Examples 1 - 4 and the conventional aluminum-based heat sink applied to TEC passive heat dissipation.

[0040] In the figure: 1 - TEC with a specification of 4 cm * 4 cm; 2 - thermal conductive silicone grease; 3 - aluminum-based heat sink; 4 - high thermally conductive and insulating phase change material. Detailed Embodiments

[0041] The technical solution of the present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings. In the present invention, unless otherwise specified, all devices and raw materials can be purchased or are commonly used in this industry. The methods in the following embodiments are conventional methods in this field unless otherwise specified.

[0042] Example 1

[0043] (1) Preparation of an anodized modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this embodiment is a 2% sodium hydroxide solution) to remove oil stains, dust, and oxides on the surface of the aluminum-based heat sink layer. Then, place the aluminum-based heat sink into an electrolytic cell containing a sulfuric acid solution with a mass concentration of 15%, and perform anodic oxidation using a pulsed current oxidation power supply. The voltage is 20V, the anodic oxidation pulse frequency is 2kHz, the duty cycle of anodic oxidation is 6%, the oxidation temperature is 0°C, and the oxidation time is 80 minutes. Finally, the thickness of the anodized modified layer is 25um. In this embodiment, the heat dissipation teeth of the aluminum-based heat sink are in the shape of a cuboid, with dimensions of 4cm * 4cm and a thickness of 5mm.

[0044] (2) Preparation of the phase change material precursor: First, mix a phase change component with a mass fraction of 7% (paraffin microcapsules with a phase change temperature of 48°C) with a heat conduction medium with a mass fraction of 6% (boron nitride), and then add a thermosetting elastic matrix (PDMS) with a mass fraction of 87% for preliminary mixing. The obtained mixed material is centrifugally stirred at a speed of 800rpm for 15 minutes to mix and defoam, and a composite thermally conductive and insulating phase change material precursor is prepared.

[0045] (3) CNC dispensing coating and curing: 2g of the thermally conductive and insulating phase change material precursor is evenly coated on the surface of the heat dissipation teeth of the aluminum-based heat sink prepared with the anodized modified layer by CNC dispensing at a speed of 15cm / s and a dispensing pressure of 400kpa (the nozzle size is 32G). The dispensing path is as Figure 2 shown, and it is heated and cured at 150°C for 0.5h to form a stable and tight fit.

[0046] Example 2

[0047] (1) Preparation of an anodized modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this embodiment is a 2% sodium hydroxide solution) to remove oil stains, dust, and oxides on the surface of the aluminum-based heat sink layer. Then, place the aluminum-based heat sink into an electrolytic cell containing a sulfuric acid solution with a mass concentration of 20%, and perform anodic oxidation using a pulsed current oxidation power supply. The voltage is 25V, the anodic oxidation pulse frequency is 10kHz, the duty cycle of anodic oxidation is 17%, the oxidation temperature is 22°C, and the oxidation time is 50 minutes. Finally, the thickness of the anodized modified layer is 25um. In this embodiment, the heat dissipation teeth of the aluminum-based heat sink are in the shape of a cylinder, with dimensions of 4cm * 4cm and a thickness of 5mm..

[0048] (2) Preparation of phase change material precursor: First, mix paraffin microcapsules with a phase change temperature of 48 °C as the phase change component at a mass fraction of 9% and boron nitride as the heat conduction medium at a mass fraction of 5%, and then add a thermosetting elastic matrix (PDMS) at a mass fraction of 86% for preliminary mixing; centrifuge and stir the obtained mixed material at a speed of 1400 rpm for 13 minutes to mix well and defoam, so as to prepare a composite thermally conductive and insulating phase change material precursor.

[0049] (3) CNC dispensing coating and curing: Dispense 2 g of the thermally conductive and insulating phase change material precursor by CNC dispensing at a speed of 10 cm / s and an adhesive outlet pressure of 450 kPa (the nozzle size is 35G) evenly on the surface of the heat dissipation teeth of the aluminum-based heat sink with an anodized modified layer, and the dispensing path is as Figure 2 shown, and heat and cure at 90 °C for 1.5 h to form a stable and tight fit.

[0050] Example 3

[0051] (1) Preparation of anodized modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this example is a 2% sodium hydroxide solution) to remove oil stains, dust and oxides on the surface of the aluminum-based heat sink layer, and then put the aluminum-based heat sink into an electrolytic cell containing a sulfuric acid solution with a mass concentration of 18%, and perform anodic oxidation using a pulsed current oxidation power supply, with a voltage of 120 V, an anodic oxidation pulse frequency of 30 kHz, an anodic oxidation duty cycle of 30%, an oxidation temperature of 25 °C, and an oxidation time of 20 minutes. Finally, the thickness of the anodized modified layer is 23 um. In this example, the shape of the heat dissipation teeth of the aluminum-based heat sink is a cuboid, with dimensions of 4 cm * 4 cm and a thickness of 5 mm..

[0052] (2) Preparation of phase change material precursor: First, mix paraffin microcapsules with a phase change temperature of 48 °C as the phase change component at a mass fraction of 6% and boron nitride as the heat conduction medium at a mass fraction of 6%, and then add a thermosetting elastic matrix (PDMS) at a mass fraction of 88% for preliminary mixing; centrifuge and stir the obtained mixed material at a speed of 2000 rpm for 10 minutes to mix well and defoam, so as to prepare a composite thermally conductive and insulating phase change material precursor.

[0053] (3) CNC dispensing coating and curing: Dispense 2 g of the thermally conductive and insulating phase change material precursor by CNC dispensing at a speed of 15 cm / s and an adhesive outlet pressure of 400 kPa (the nozzle size is 32G) evenly on the surface of the heat dissipation teeth of the aluminum-based heat sink with an anodized modified layer, and the dispensing path is as Figure 2 shown, and heat and cure at 25 °C for 20 h to form a stable and tight fit.

[0054] Example 4

[0055] (1) Preparation of anodized modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this example is a 2% sodium hydroxide solution) to remove oil stains, dust, and oxides on the surface of the aluminum-based heat sink layer. Then, place the aluminum-based heat sink into an electrolytic cell filled with a sulfuric acid solution with a mass concentration of 18%, and perform anodization using a pulsed current oxidation power supply. The voltage is 25V, the anodization pulse frequency is 10kHz, the duty cycle of anodization is 17%, the oxidation temperature is 22°C, and the oxidation time is 40 minutes. Finally, the thickness of the anodized modified layer is 23um. In this example, the heat dissipation teeth of the aluminum-based heat sink are cylindrical in shape, with dimensions of 4cm * 4cm and a thickness of 5mm..

[0056] (2) Preparation of phase change material precursor: First, mix a phase change component with a mass fraction of 6% (paraffin microcapsules with a phase change temperature of 48°C) and a heat conduction medium with a mass fraction of 9% (boron nitride), and then add a thermosetting elastic matrix (PDMS) with a mass fraction of 85% for preliminary mixing; centrifuge and stir the obtained mixed material at a speed of 1000rpm for 14 minutes to mix and defoam, and prepare a composite heat conduction and insulation phase change material precursor.

[0057] (3) CNC dispensing coating and curing: Dispense 2g of the heat conduction and insulation phase change material precursor onto the surface of the heat dissipation teeth of the aluminum-based heat sink with an anodized modified layer by CNC dispensing at a speed of 13cm / s and a dispensing pressure of 350kpa (the nozzle size is 30G) evenly. The dispensing path is as Figure 2 shown, and heat and cure at a temperature of 23°C for 24h to form a stable and tightly fitting structure.

[0058] Example 5

[0059] (1) Preparation of anodized modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this example is a 2% sodium hydroxide solution) to remove oil stains, dust, and oxides on the surface of the aluminum-based heat sink layer. Then, place the aluminum-based heat sink into an electrolytic cell filled with a sulfuric acid solution with a mass concentration of 15%, and perform anodization using a pulsed current oxidation power supply. The voltage is 20V, the anodization pulse frequency is 2kHz, the duty cycle of anodization is 6%, the oxidation temperature is 0°C, and the oxidation time is 80 minutes. Finally, the thickness of the anodized modified layer is 25um. In this example, the heat dissipation teeth of the aluminum-based heat sink are rectangular in shape, with dimensions of 4cm * 4cm and a thickness of 5mm.

[0060] (2) Preparation of phase change material precursor: First, mix the phase change component with a mass fraction of 7% (octadecane microcapsules with a phase change temperature of 28 °C) and the heat conduction medium with a mass fraction of 6% (boron nitride), and then add the thermosetting elastic matrix (PDMS) with a mass fraction of 87% for preliminary mixing; centrifuge and stir the obtained mixed material at a speed of 800 rpm for 15 minutes to mix well and defoam, so as to prepare a composite thermally conductive and insulating phase change material precursor.

[0061] (3) CNC dispensing coating and curing: Dispense 2 g of the thermally conductive and insulating phase change material precursor by CNC dispensing at a speed of 15 cm / s and an out-of-mouth pressure of 400 kPa (the nozzle size is 32G) evenly on the surface of the heat dissipation teeth of the aluminum-based heat sink with an anodic oxidation modified layer prepared, and the dispensing path is as Figure 2 shown, and heat and cure at 150 °C for 0.5 h to form a stable and tight fit.

[0062] Comparative example

[0063] (1) Preparation of anodic oxidation modified layer: First, use an alkaline cleaning agent (the alkaline cleaning agent used in this example is a 2% sodium hydroxide solution) to remove the oil stains, dust and oxides on the surface of the aluminum-based heat sink layer, and then put the aluminum-based heat sink into an electrolytic cell containing a sulfuric acid solution with a mass concentration of 15%, and perform anodic oxidation using a pulsed current oxidation power supply, with a voltage of 25 V, an anodic oxidation pulse frequency of 10 kHz, an anodic oxidation duty cycle of 17%, an oxidation temperature of 22 °C, and an oxidation time of 50 minutes. Finally, the thickness of the oxidation modified layer obtained is 25 μm. In this example, the shape of the heat dissipation teeth of the aluminum-based heat sink is a cuboid, with dimensions of 4 cm * 4 cm and a thickness of 5 mm. This step is the same as that in Example 1.

[0064] (2) Preparation of phase change material precursor: First, mix the heat conduction medium with a mass fraction of 15% (boron nitride), and then add the thermosetting elastic matrix (PDMS) with a mass fraction of 85% for preliminary mixing; centrifuge and stir the obtained mixed material at a speed of 800 rpm for 15 minutes to mix well and defoam, so as to prepare a composite precursor without phase change material.

[0065] (3) CNC dispensing coating and curing: Dispense 2 g of the composite precursor without phase change material by CNC dispensing at a speed of 15 cm / s and an out-of-mouth pressure of 400 kPa (the nozzle size is 32G) evenly on the surface of the heat dissipation teeth of the aluminum-based heat sink with an anodic oxidation modified layer prepared, and heat and cure at 150 °C for 0.5 h to form a stable and tight fit.

[0066] Effect verification of the embodiments and comparative examples of the present invention:

[0067] Assemble the radiator coated with the mixed colloid prepared above with a TEC with a specification of 4 cm * 4 cm and thermal conductive grease. The structure is as Figure 3 shown. When the TEC continuously operates at a constant voltage of 5 V and a total power of 10 W in an environment of 25 °C, the TECs corresponding to Examples 1 - 5 can respectively maintain the cold end temperature below 25 °C for 77 s / 60 s / 56 s / 54 s / 35 s, while the comparative example can only maintain the cold end temperature below 25 °C for 18 s. The gap between the comparative example and the examples fully demonstrates the significant optimization effect of the present invention on TEC heat dissipation. By combining the phase change material with the aluminum-based radiator, the present invention can extend the effective working time of the TEC to 327%. At the same time, by comparing Examples 1 and 2, when the proportion of the phase change component exceeds the thermal conductive medium, due to the reduction in thermal conductivity, the time for maintaining the TEC will be significantly reduced; and by comparing Examples 3 and 4, when the proportion of the thermal conductive medium exceeds the phase change component, the time for maintaining the normal operation of the TEC will also show a small decrease. It shows that the optimal ratio of the phase change component to the thermal conductive medium in the present invention should be around 1:1. By comparing Example 5 with Example 1, it can be seen that phase change components with different latent heats and phase change temperature points (paraffin: 160 J / g 48 °C; octadecane: 240 J / g 28 °C) have different optimization effects on TEC heat dissipation. The heating duration of the TEC is longer and the power is larger. Even if the material with a low phase change temperature has a large phase change latent heat, it will quickly reach the heat absorption saturation point and lose the heat dissipation optimization function. For the present invention, for a TEC with a power of about 10 W, the appropriate phase change temperature point should be set at least 48 °C.

[0068] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation, characterized in that: The aluminum-based all-solid-state phase change heat sink comprises an aluminum-based heat sink layer, an oxidation-modified layer and a high thermal conductivity insulating phase change layer which are stacked in sequence from bottom to top; the surface of the aluminum-based heat sink layer is evenly distributed with heat dissipation teeth for increasing the heat exchange area; the oxidation-modified layer is grown on the surface of the aluminum-based heat sink layer by anodizing to enhance the surface energy and interlayer adhesion; the high thermal conductivity insulating phase change layer is evenly coated on the oxidation-modified layer by CNC dispensing and then cured into shape, and its main materials are phase change microcapsules, insulating thermal conductive medium and thermosetting elastic matrix.

2. The aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 1, characterized in that: The heat dissipation teeth on the surface of the aluminum-based heat sink may be cylindrical, rectangular or in any other shape.

3. The aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 1, characterized in that: The high thermal conductivity insulating phase change layer is prepared by uniformly mixing the following components by mass percentage: 5-10% phase change component, 75-85% thermosetting elastic matrix, and 10-15% insulating thermal conductive medium, the sum of the three being 100%; wherein the phase change component is wrapped by a microcapsule wall to form a phase change microcapsule; the thermal conductivity of the high thermal conductivity insulating phase change layer is higher than 1W / m·K, and the resistivity is greater than 15000Ω·m.

4. The aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 3, characterized in that: The phase change components include, but are not limited to: one or more of paraffin microcapsules and octadecane microcapsules; The thermosetting elastic matrix includes, but is not limited to: one or more of polydimethylsiloxane, fluororubber, polyurethane, and polyacrylate; The insulating heat-conducting medium includes, but is not limited to: one or more of aluminum nitride, boron nitride, zirconium oxide, and aluminum oxide.

5. The aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 3, characterized in that: The phase-change microcapsules are of core-shell structure, with a particle size of 5-10um, a phase-change temperature of 5-45°C, and an enthalpy value higher than 120kJ / kg; The wall material of the phase change microcapsule is one or more combinations of inorganic substances and polymers. The wall material of the phase-change microcapsule contains any one of paraffin and octadecane.

6. The aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 1, characterized in that: The total thickness of the aluminum-based heat sink layer is 3-5 mm, the thickness of the oxidation-modified layer is 23-25 ​​um, and the thickness of the high thermal conductivity insulating phase change layer is 1-3 mm.

7. A method for preparing an aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step (1) preparing an anodized modified layer: first, the surface of the aluminum-based heat sink layer is cleaned, and then the aluminum-based heat sink is placed in an electrolytic cell filled with sulfuric acid solution, and powered on for anodization to obtain an oxidized modified layer with a thickness of 23-25 ​​μm; the surface of the aluminum-based heat sink layer is evenly distributed with heat dissipation teeth; Step (2) preparing a phase change material precursor: firstly adding a phase change component and an insulating heat-conducting medium, and then adding a thermosetting elastic matrix for preliminary mixing; the obtained mixture is fully centrifuged and stirred in a rotating centrifuge to mix and defoam, so as to obtain a coatable heat-conducting insulating phase change material precursor; Step (3) CNC dispensing coating and curing: The coatable thermally conductive insulating phase change material precursor obtained in step (2) is evenly coated on the surface of the heat dissipation teeth of the aluminum-based heat sink layer with an anodized modified layer prepared in step (1), and cured to form a stable and tight fit.

8. A method for preparing an aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 7, characterized in that: In the step (1): The mass concentration of the sulfuric acid solution is 15% to 20%; In the anodizing process, a pulse current oxidation power supply is used, the voltage is 20-120V, the anodizing pulse frequency is 2kHz-30kHz, the anodizing duty cycle is 6%-30%, the oxidation temperature is 0-25°C, and the oxidation time is 20-80 minutes.

9. A method for preparing an aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 7, characterized in that: In the step (2), the centrifugal stirring speed is 800-2000 rpm, and the stirring time is 10-15 minutes.

10. A method for preparing an aluminum-based all-solid-state phase-change heat sink for TEC passive heat dissipation according to claim 7, characterized in that: In the step (3): The coating method is CNC dispensing coating; The mass density of the CNC dispensing coating phase change material is 0.2-0.5 g / cm 2 ; The CNC dispensing coating speed is 10-15 cm / s; The size of the CNC dispensing coating nozzle is 30-35G; The glue dispensing pressure of the CNC glue coating is 350-450kpa; The curing temperature is 23-25° C. and the curing time is 20-24 hours; or the curing temperature is 90-150° C. and the curing time is 0.25-1.5 hours.

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