Phase-change alloy heat sink structure for heat dissipation of electronic device and use method of phase-change alloy heat sink structure

Abstract

The invention discloses a phase change alloy heat sink structure for heat dissipation of an electronic device and a use method of the phase change alloy heat sink structure. The heat sink structure comprises an aluminum alloy shell and at least two independent cavities arranged in the shell, and the cavities are sequentially arranged in the direction from the hot end to the cold end of a heat sink. The cavities are filled with phase change alloy heat storage materials respectively, and the phase change alloy heat storage materials are sequentially filled into the cavities from the hot end to the cold end of the heat sink according to the sequence of the phase change temperatures from high to low. Through the design of the packaging structure and the optimized combination of multiple phase change heat storage alloys, the temperature gradient of the heat sink from the hot end to the cold end is reduced, the multiple phase change alloys are made to continuously generate solid-liquid phase change from the cold end to the hot end in a short time, the heat storage capacity of the phase change materials in a limited space is fully exerted, and the heat storage efficiency of the phase change materials is improved. The temperature equalization and temperature control capabilities of the phase change heat sink are greatly improved, and the phase change heat sink is suitable for heat dissipation of electronic components in aircrafts with strictly limited working spaces.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic device thermal management, and in particular relates to a phase change alloy heat sink structure for heat dissipation of electronic devices and a use method thereof. Background Art

[0002] The external environment of the aircraft is a high-temperature environment during high-speed operation, so the waste heat generated by the integrated devices inside its control system when working at high power can only be digested in a short time using the limited internal space. The working reliability of the electronic devices of the device is very sensitive to temperature. Generally, the reliability decreases by 5% for every 1°C increase in the device temperature at the level of 70-80°C. Without reasonable heat transmission, diffusion or storage, local high heat flux density will lead to heat accumulation and serious local overheating, which will lead to thermal failure of the device and directly affect the working performance and life of the equipment. Intelligence and integration have always been the development direction of aircraft. Intelligence requires higher-power components and integration requires higher-density device arrangement, which means that the heating problem of the control system will be more severe. The combination of transmission and storage is the mainstream method of thermal management of current spacecraft control systems. The representative thermal management solution is to use aluminum alloy as the heat conduction and load-bearing structure, paraffin or phase change alloy as the heat storage material, and encapsulate the heat storage material in the alloy to make a radiator. The maximum operating temperature of silicon-based chips is 150°C, and it is generally controlled not to exceed 120°C during normal operation. Therefore, materials with a phase change temperature of about 60 to 120°C for energy storage materials can be used as fillers for phase change heat sinks.

[0003] The main dimensions for evaluating the performance of a heat sink structure include the amount of overall heat storage and the heat storage efficiency during the working time. Therefore, in some devices that need to solve thermal problems in a short time, phase change alloys are often used as heat storage materials to prepare heat sinks. In order to facilitate the integration and modularization of equipment, such as Figure 1 , 2 As shown, the current heat sink is generally matched with the circuit board 4 in the form of a card. The side of the heat sink close to the circuit board 4 is the hot end, and the side away from it is the cold end. When the device 3 on the circuit board is working, the heat is input from the hot end of the heat sink, and the aluminum alloy shell 1 conducts the heat to the heat storage material 2. As the working time of the device increases, the temperature of the heat sink gradually increases. When the temperature of the heat storage material reaches its "solid→liquid" phase change point, a phase change occurs to absorb a large amount of heat, and the temperature hardly increases. This achieves the absorption and storage of the heat generated by the device and alleviates its overheating problem.

[0004] However, for phase change alloys, the thermal conductivity of the solid phase is much higher than that of the liquid phase. Therefore, when the phase change material at the hot end liquefies, the ability and efficiency of the heat sink to transfer heat from the hot end to the cold end is greatly weakened, which causes the device to overheat before the heat storage material at the far end can fully function. In order to further improve the heat dissipation capacity of the phase change heat sink, it is of great practical significance to develop a new heat sink structure and use method for aircraft operating conditions. Summary of the invention

[0005] The purpose of the present invention is to provide a phase change alloy heat sink structure for heat dissipation of electronic devices. By utilizing the difference in phase change temperature of the phase change alloy, the cold end of the heat sink undergoes a "solid→liquid" phase change first, and the hot end of the heat sink undergoes a "solid→liquid" phase change last, so as to overcome the problem of reduced thermal conductivity caused by the hot end of the original single phase change material heat sink undergoing phase change first, thereby reducing the temperature gradient of the heat sink and improving its temperature uniformity and temperature control capabilities.

[0006] Another object of the present invention is to provide a method for using the phase change alloy heat sink structure.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A phase change alloy heat sink structure for heat dissipation of electronic devices, the heat sink structure comprises an aluminum alloy shell and at least two independent cavities arranged in the shell, the cavities are arranged in sequence from the hot end to the cold end of the heat sink; each cavity is filled with a phase change alloy heat storage material, and the phase change alloy heat storage material is filled into the cavity in sequence from the hot end to the cold end of the heat sink in the order of phase change temperature from high to low.

[0009] Preferably, the heat sink structure comprises two independent cavities, the cavity close to the hot end is filled with high-temperature phase-change alloy heat storage material, and the cavity close to the cold end is filled with medium-temperature phase-change alloy heat storage material.

[0010] Among them, the composition of the high-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 50.5-51.5%, cadmium accounts for 20.5-21.5%, and tin accounts for 27.5-28.5%; the composition of the medium-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 49.5-50.5%, tin accounts for 12.5-13.5%, lead accounts for 26.5-27.5%, and cadmium accounts for 9.5-10.5%.

[0011] Preferably, the heat sink structure includes three independent cavities, and the phase change alloy heat storage materials filled into the cavities in sequence from the hot end to the cold end of the heat sink are high-temperature phase change alloy heat storage material, medium-temperature phase change alloy heat storage material, and low-temperature phase change alloy heat storage material.

[0012] Among them, the composition of the high-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 50.5-51.5%, cadmium accounts for 20.5-21.5%, and tin accounts for 27.5-28.5%; the composition of the medium-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 49.5-50.5%, tin accounts for 12.5-13.5%, lead accounts for 26.5-27.5%, and cadmium accounts for 9.5-10.5%; the composition of the low-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 38.5-39.5%, indium accounts for 42.5-43.5%, and tin accounts for 17.5-18.5%.

[0013] A method for using the phase change alloy heat sink structure comprises the following steps:

[0014] (1) Based on the requirements of the device application scenario, the structure of the aluminum alloy shell is designed through computer simulation. The physical properties of the aluminum alloy shell material, the phase change alloy heat storage material, and the heat source are used as input factors, and the amount and rate of heat storage are used as output indicators to optimize the size and shape of each cavity of the aluminum alloy packaging shell. The minimum thickness of the cavity can be zero, that is, the corresponding heat storage material is not filled, but at least two cavities must be retained. The optimized heat sink structure should meet the requirements that the temperature gradient from the hot end to the cold end of the heat sink is similar to the phase change temperature gradient trend of various heat storage materials, and various heat storage materials undergo "solid→liquid" phase change from the cold end to the hot end in sequence.

[0015] (2) using 3D printing technology to prepare the aluminum alloy shell structure optimized in step (1), injecting each phase change alloy heat storage material in the form of liquid into each cavity under vacuum conditions, and sealing the injection hole by welding;

[0016] (3) After finishing the shape of the heat sink, the high-temperature phase change material side of the heat sink is bonded to the heat generating unit, and the heat is transferred to the high-temperature phase change material, the medium-temperature phase change material, and the low-temperature phase change material in sequence through the aluminum alloy shell. Until the low-temperature phase change material reaches the "solid→liquid" phase change temperature and begins to change phase, then the medium-temperature phase change material reaches the "solid→liquid" phase change temperature and begins to change phase, and finally the high-temperature phase change material reaches the "solid→liquid" phase change temperature and begins to change phase, thereby greatly improving the temperature uniformity and temperature control capabilities of the phase change heat sink.

[0017] Beneficial effects of the present invention:

[0018] The present invention reduces the temperature gradient from the hot end to the cold end of the heat sink by designing the packaging structure and optimizing the combination of multiple phase-change heat storage alloys, and enables the three phase-change alloys to continuously undergo a "solid to liquid" phase change from the cold end to the hot end in a short time, giving full play to the heat storage capacity of the phase-change material in a limited space, overcoming the problems of the existing heat sinks of single phase-change materials encapsulated in aluminum alloy, greatly improving the temperature uniformity and temperature control capabilities of the phase-change heat sink, and is suitable for heat dissipation of electronic components in aircraft with strictly limited working space. The present invention can be applied to the thermal management of equipment such as arrow-borne radars, lasers, optoelectronic pods of unmanned aerial vehicles, and constant temperature chassis. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The schematic cross-sectional view of the main view of the heat sink structure of the existing aluminum alloy encapsulating a single phase change alloy.

[0020] Figure 2 A schematic cross-sectional view of a side view of a heat sink structure of a single phase change alloy encapsulated in an existing aluminum alloy.

[0021] Figure 3 It is a schematic cross-sectional view of the front view of the heat sink structure of the aluminum alloy encapsulating two phase change alloys of the present invention.

[0022] Figure 4 It is a schematic cross-sectional view of a side view of a heat sink structure of two phase change alloys encapsulated by aluminum alloy according to the present invention.

[0023] Figure 5 It is a schematic cross-sectional view of the front view of the heat sink structure of the aluminum alloy encapsulating three phase change alloys according to the present invention.

[0024] Figure 6 It is a schematic cross-sectional view of the side view of the heat sink structure of the aluminum alloy encapsulating three phase change alloys according to the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 3 , 4 As shown, a heat sink structure of the present invention includes an aluminum alloy shell 1 and two independent cavities arranged in the shell, and the two cavities are arranged in sequence from the hot end to the cold end of the heat sink; the cavity close to the hot end is filled with a high-temperature phase-change alloy heat storage material 21, and the cavity close to the cold end is filled with a medium-temperature phase-change alloy heat storage material 22.

[0027] like Figure 5 , 6As shown, another heat sink structure of the present invention includes an aluminum alloy shell 1 and three independent cavities arranged in the shell, and the three cavities are arranged in sequence from the hot end to the cold end of the heat sink; the cavity close to the hot end is filled with a high-temperature phase-change alloy heat storage material 21, the middle cavity is filled with a medium-temperature phase-change alloy heat storage material 22, and the cavity close to the cold end is filled with a low-temperature phase-change alloy heat storage material 23;

[0028] In the heat sink structure of the present invention, the composition of the filled high-temperature phase-change alloy heat storage material in terms of weight percentage is as follows: high-temperature phase-change alloy: bismuth accounts for 50.5-51.5%, cadmium accounts for 20.5-21.5%, and tin accounts for 27.5-28.5%; medium-temperature phase-change alloy: bismuth accounts for 49.5-50.5%, tin accounts for 12.5-13.5%, lead accounts for 26.5-27.5%, and cadmium accounts for 9.5-10.5%; low-temperature phase-change alloy: bismuth accounts for 38.5-39.5%, indium accounts for 42.5-43.5%, and tin accounts for 17.5-18.5%.

[0029] Comparative Example 1

[0030] like Figure 1 , 2 As shown, the three-dimensional dimensions of the heat sink are: 140mm long × 70mm wide × 10mm thick, and the power of the heat source (device) is 50W. The aluminum alloy packaging shell prepared by 3D printing is precisely processed, and the shell wall thickness is 1.5mm. The composition of the phase change alloy heat storage material by weight percentage is: bismuth accounts for 50.0%, tin accounts for 13.0%, lead accounts for 27.0%, and cadmium accounts for 10.0%. The phase change temperature range of this alloy is 70-90℃, the solid thermal conductivity is 40W / mK, the liquid thermal conductivity is 20W / mK, and the phase change enthalpy per unit volume is 360J / cm 3 Under vacuum conditions, the liquid phase change alloy is injected into the aluminum alloy shell. After cooling and solidification, the filling port is welded and sealed to prepare a heat sink product. Figure 1 , 2 As shown, assemble the heat sink and device together, turn on the heat source (device), and measure Figure 1 , 2 The temperatures of the temperature measurement points P1 (geometric center of the upper surface of the heat sink), P2 (three-dimensional geometric center), and P3 (geometric center of the lower surface of the heat sink) are shown in Table 1. When the temperature P1 of the heat source (device) reaches above 120°C, it is considered overtemperature. In this comparative example, P1 reaches 120°C at 300s.

[0031] Table 1 Temperatures of various temperature measurement points in Comparative Example 1

[0032]

[0033] Comparative Example 2

[0034] like Figure 1 , 2 As shown, the three-dimensional dimensions of the heat sink are: 140mm long × 70mm wide × 10mm thick, and the power of the heat source (device) is 50W. The aluminum alloy packaging shell prepared by 3D printing is precisely processed, and the shell wall thickness is 1.5mm. The composition of the phase change alloy heat storage material by weight percentage is: bismuth accounts for 51.0%, cadmium accounts for 21.0%, and tin accounts for 28.0%. The phase change temperature range of this alloy is 90-110℃, the solid thermal conductivity is 30W / mK, the liquid thermal conductivity is 15W / mK, and the phase change enthalpy per unit volume is 540J / cm 3 Under vacuum conditions, the liquid phase change alloy is injected into the aluminum alloy shell. After cooling and solidification, the filling port is welded and sealed to prepare a heat sink product. Figure 1 , 2 As shown, assemble the heat sink and device together, turn on the heat source (device), and measure Figure 1 , 2 The temperature of the measuring point is shown in Table 2. When the temperature P1 of the heat source (device) reaches above 120°C, it is over-temperature. In this comparative example, P1 reaches 120°C at 400 seconds.

[0035] Table 2 Temperatures of various temperature measurement points in Comparative Example 2

[0036]

[0037] Example 1

[0038] like Figure 3 , 4 As shown, the three-dimensional dimensions of the heat sink are: 140mm long × 70mm wide × 10mm thick, and the power of the heat source (device) is 50W. After precision machining, the aluminum alloy package shell prepared by 3D printing has a shell wall thickness of 1.5mm, the two cavities have the same size, and the thickness of the partition layer is also 1.5mm. The composition of the two phase change alloy heat storage materials by weight percentage is: medium temperature phase change alloy: bismuth accounts for 50.2%, tin accounts for 12.8%, lead accounts for 27.1%, and cadmium accounts for 9.9%; high temperature phase change alloy: bismuth accounts for 51%, cadmium accounts for 21.3%, and tin accounts for 27.7%. The phase change temperature range of the low temperature phase change alloy is 70-90℃, the solid thermal conductivity is 40W / mK, the liquid thermal conductivity is 20W / mK, and the unit volume phase change enthalpy is 360J / cm 3 The phase change temperature range of the high-temperature phase change alloy is 90-110°C, the solid thermal conductivity is 30W / mK, the liquid thermal conductivity is 15W / mK, and the unit volume phase change enthalpy is 540J / cm 3Under vacuum conditions, the liquid phase change alloy is injected into the two cavities of the aluminum alloy shell respectively. After cooling and solidification, the filling port is welded and sealed to prepare a heat sink product. Figure 3 , 4 As shown, assemble the heat sink and device together, turn on the heat source (device), and measure Figure 3 , 4 The temperature of the temperature measuring point is shown in Table 3. When the temperature P1 of the heat source (device) reaches above 120°C, it is over-temperature. In this embodiment, P1 reaches 120°C at 500 seconds.

[0039] Table 3 Temperatures of various temperature measurement points in Example 1

[0040]

[0041] Example 2

[0042] like Figure 5 , 6 As shown, the three-dimensional dimensions of the heat sink are: 140mm long × 70mm wide × 10mm thick, and the power of the heat source (device) is 50W. After precision machining, the aluminum alloy package shell prepared by 3D printing has a shell wall thickness of 1.5mm, the three cavities have the same size, and the thickness of the two partition layers is also 1.5mm. The composition of the three phase change alloy heat storage materials by weight percentage is as follows: low-temperature phase change alloy: bismuth accounts for 39.0%, indium accounts for 43.0%, and tin accounts for 18.0%; medium-temperature phase change alloy: bismuth accounts for 49.9%, tin accounts for 13.1%, lead accounts for 26.8%, and cadmium accounts for 10.2%; high-temperature phase change alloy: bismuth accounts for 50.8%, cadmium accounts for 20.9%, and tin accounts for 28.3%. The phase change temperature range of the low-temperature phase change alloy is 60-70℃, the solid thermal conductivity is 20W / mK, the liquid thermal conductivity is 10W / mK, and the unit volume phase change enthalpy is 300J / cm 3 The phase change temperature range of the medium-temperature phase change alloy is 70-90°C, the solid thermal conductivity is 40W / mK, the liquid thermal conductivity is 20W / mK, and the unit volume phase change enthalpy is 360J / cm 3 The phase change temperature range of the high-temperature phase change alloy is 90-110°C, the solid thermal conductivity is 30W / mK, the liquid thermal conductivity is 15W / mK, and the unit volume phase change enthalpy is 540J / cm 3 Under vacuum conditions, the liquid phase change alloy is injected into the two cavities of the aluminum alloy shell respectively. After cooling and solidification, the filling port is welded and sealed to prepare a heat sink product. Figure 5 , 6 As shown, assemble the heat sink and device together, turn on the heat source (device), and measure Figure 5 , 6The temperature of the measuring point is shown in Table 4. When the temperature P1 of the heat source (device) reaches above 120°C, it is over-temperature. In this embodiment, P1 reaches 120°C at the 600th second.

[0043] Table 4 Temperatures of various temperature measurement points in Example 2

[0044]

[0045] The above contents are only basic descriptions of the concept of the present invention, and any equivalent changes made according to the technical solution of the present invention belong to the protection scope of the present invention.

Claims

1. A phase change alloy heat sink structure for heat dissipation of electronic devices, characterized in that: The heat sink structure includes an aluminum alloy shell and at least two independent cavities arranged in the shell, and the cavities are arranged in sequence from the hot end to the cold end of the heat sink; each cavity is filled with a phase change alloy heat storage material, and the phase change alloy heat storage material is filled into the cavity in sequence from the hot end to the cold end of the heat sink in the order of phase change temperature from high to low.

2. The phase change alloy heat sink structure for heat dissipation of electronic devices according to claim 1, characterized in that: The heat sink structure includes two independent cavities, the cavity close to the hot end is filled with a high-temperature phase-change alloy heat storage material, and the cavity close to the cold end is filled with a medium-temperature phase-change alloy heat storage material.

3. The phase change alloy heat sink structure for heat dissipation of electronic devices according to claim 2, characterized in that: The composition of the high-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 50.5-51.5%, cadmium accounts for 20.5-21.5%, and tin accounts for 27.5-28.5%; the composition of the medium-temperature phase-change alloy heat storage material according to weight percentage is: bismuth accounts for 49.5-50.5%, tin accounts for 12.5-13.5%, lead accounts for 26.5-27.5%, and cadmium accounts for 9.5-10.5%.

4. The phase change alloy heat sink structure for heat dissipation of electronic devices according to claim 1, characterized in that: The heat sink structure includes three independent cavities, and the phase change alloy heat storage materials filled into the cavities in sequence from the hot end to the cold end of the heat sink are high-temperature phase change alloy heat storage material, medium-temperature phase change alloy heat storage material, and low-temperature phase change alloy heat storage material.

5. The phase change alloy heat sink structure for heat dissipation of electronic devices as claimed in claim 4, characterized in that: The high-temperature phase-change alloy heat storage material has a composition according to weight percentage: bismuth accounts for 50.5-51.5%, cadmium accounts for 20.5-21.5%, and tin accounts for 27.5-28.5%; the medium-temperature phase-change alloy heat storage material has a composition according to weight percentage: bismuth accounts for 49.5-50.5%, tin accounts for 12.5-13.5%, lead accounts for 26.5-27.5%, and cadmium accounts for 9.5-10.5%; the low-temperature phase-change alloy heat storage material has a composition according to weight percentage: bismuth accounts for 38.5-39.5%, indium accounts for 42.5-43.5%, and tin accounts for 17.5-18.5%.

6. A method for using the phase change alloy heat sink structure according to any one of claims 1 to 5, characterized in that: The steps include: (1) Based on the application scenario requirements of the device, the structure of the aluminum alloy shell is designed through computer simulation. The physical properties of the aluminum alloy shell material, phase change alloy heat storage material, and heat source conditions are used as input factors, and the amount and rate of heat storage are used as output indicators to optimize the size and shape of each cavity of the aluminum alloy packaging shell; (2) using 3D printing technology to prepare the aluminum alloy shell structure optimized in step (1), injecting each phase change alloy heat storage material in the form of liquid into each cavity under vacuum conditions, and sealing the injection hole by welding; (3) After fine processing of the heat sink shape, the high-temperature phase change material side of the heat sink is bonded to the heat generating unit, and the heat is transferred to the high-temperature phase change material, the medium-temperature phase change material, and the low-temperature phase change material in sequence through the aluminum alloy shell.

7. The method for using the phase change alloy heat sink structure according to claim 6, characterized in that: In the step (1), the optimized design of the heat sink structure is achieved by adjusting the size of each cavity and the shape of the reinforcing ribs inside the cavity.

8. The method for using the phase change alloy heat sink structure according to claim 6, characterized in that: In the step (1), the optimized heat sink structure should satisfy the condition that the temperature gradient from the hot end to the cold end of the heat sink is similar to the phase change temperature gradient trend of the various phase change alloy heat storage materials, and the various phase change alloy heat storage materials undergo "solid→liquid" phase change in sequence from the cold end to the hot end.

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