A thermal management system

Abstract

The present invention relates to a thermal management system, which includes a first flexible heat-conducting film, a second flexible heat-conducting film, and a sealing interlayer. A heating element is disposed on the first flexible heat-conducting film, and the first flexible heat-conducting film encloses a first accommodating cavity; the second flexible heat-conducting film is disposed within the first accommodating cavity, and the second flexible heat-conducting film encloses a second accommodating cavity, and a phase change material is filled in the second accommodating cavity, and the phase change material is used for storing and releasing heat; the sealing interlayer is disposed between the first flexible heat-conducting film and the second flexible heat-conducting film, and a thermal management liquid is filled in the sealing interlayer, and the thermal management liquid can undergo a phase change when heated to transfer the heat of the sealing interlayer, and further transfer the heat of the first flexible heat-conducting film and the second flexible heat-conducting film. The thermal management system of the present invention stores heat through the phase change material and the sandwich structure of the first flexible heat-conducting film and the second flexible heat-conducting film, improving the heat conduction performance of the flexible heat-conducting material.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft thermal management, and particularly relates to a thermal management system. Background Art

[0002] The rapid development of China's space industry has promoted the development of ultra-large-scale integrated circuits and electronic devices for spacecraft towards high integration, high frequency, high power, and intelligence. Among them, the heat flux density of high-power devices represented by spaceborne laser payloads, manned space projects, and deep space exploration has increased significantly, seriously affecting the performance and reliability of spacecraft. To ensure the safe operation of spacecraft in the deep space environment, the heat generated in the chips of the spacecraft system should be promptly exported and dissipated into the cosmic space in the form of thermal radiation.

[0003] Phase change heat transfer technology has the advantages of high efficiency, high stability, and long life. The heat pipe can achieve rapid heat transfer in a small space through the phase change of the internal working fluid, and has become the primary choice for solving the current heat dissipation problem of electronic devices.

[0004] Flexible thermal conductive materials such as polyimide have been widely used in the aerospace field due to their light structure, excellent electrical insulation and mechanical properties. However, the application of flexible thermal conductive materials is limited because of their poor thermal conductivity. Summary of the Invention

[0005] Based on this, the present invention provides a thermal management system capable of improving the thermal conductivity of flexible thermal conductive materials.

[0006] A thermal management system for dissipating heat from a heat-generating element, comprising:

[0007] A first flexible thermal conductive film, the heat-generating element is disposed on the first flexible thermal conductive film, and the first flexible thermal conductive film encloses a first accommodating cavity;

[0008] A second flexible thermal conductive film, the second flexible thermal conductive film is disposed in the first accommodating cavity, the second flexible thermal conductive film encloses a second accommodating cavity, and a phase change material is filled in the second accommodating cavity for storing and releasing heat; and

[0009] A sealing interlayer, the sealing interlayer is disposed between the first flexible thermal conductive film and the second flexible thermal conductive film, and a thermal management liquid is filled in the sealing interlayer. The thermal management liquid can undergo a phase change when heated to transfer the heat of the sealing interlayer, and further transfer the heat of the first flexible thermal conductive film and the second flexible thermal conductive film.

[0010] Preferably, the sealed interlayer includes a liquid absorption core disposed between the first flexible heat conducting film and the second flexible heat conducting film. The liquid absorption core has a plurality of capillary channels, and the heat management liquid circulates within the plurality of capillary channels.

[0011] Preferably, the liquid absorption core includes one of a polyethylene polymer film, a polytetrafluoroethylene polymer film, and a polypropylene polymer film.

[0012] Preferably, the thickness of the liquid absorption core is 0.05 - 0.1 mm.

[0013] Preferably, the sealed interlayer further includes a support mesh disposed between the first flexible heat conducting film and the second flexible heat conducting film for supporting the first flexible heat conducting film and the second flexible heat conducting film.

[0014] Preferably, the phase change material is at least one alkane having 14 - 30 carbon atoms.

[0015] Preferably, the phase change temperature of the phase change material is 5.5 - 65.5 °C.

[0016] Preferably, the heat management liquid includes at least one of deionized water, methanol, ethanol, and a fluorinated liquid.

[0017] Preferably, the pressure in the sealed interlayer ≤ 10 Pa.

[0018] Preferably, the heating element is fixed to the first flexible heat conducting film by bonding or 3D printing.

[0019] Compared with the existing solutions, the present invention has the following beneficial effects:

[0020] For the heat management system of the present invention, part of the heat generated by the heating element is dissipated in the form of heat radiation through the first flexible heat conducting film, and another part is transferred and stored in the phase change material through the first flexible heat conducting film and the second flexible heat conducting film. During the non - working cycle of the heating element, the phase change material releases the stored heat. The released heat is transferred to the first flexible heat conducting film through the second flexible heat conducting film and dissipated in the form of heat radiation. A sealed interlayer is provided between the first flexible heat conducting film and the second flexible heat conducting film, and filled with a heat management liquid. The heat management liquid is heated and transformed into heat management steam, and the heat generated by the heating element is transferred between the first flexible heat conducting film and the second flexible heat conducting film through the heat management steam, thereby improving the heat conduction performance of the flexible heat conducting material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross - sectional view of the heat management system of an embodiment;

[0022] Figure 2Top view of a thermal management system according to an embodiment;

[0023] Figure 3 Partial cross-sectional view of a thermal management system according to an embodiment;

[0024] Figure 4 Partial cross-sectional view of a thermal management system according to an embodiment.

[0025] Wherein, 100. Heating element; 200. First flexible heat-conducting film; 300. Second flexible heat-conducting film; 400. Phase change material; 500. Sealing interlayer; 510. Liquid-absorbing core; 520. Support mesh. Specific implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0027] The experimental methods in the following embodiments are all conventional methods unless otherwise specified. The test materials and reagents used in the following embodiments can all be obtained from commercial channels unless otherwise specified. In the following embodiments, all quantitative tests are set with three repeated experiments, and the data are the average value or average value ± standard deviation of the three repeated experiments.

[0028] In addition, "and / or" throughout the text includes three solutions. Taking A and / or B as an example, it includes the A technical solution, the B technical solution, and the technical solution that both A and B are satisfied at the same time; in addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0029] Reference Figure 1, the present invention provides a thermal management system for dissipating heat from a heating element 100, including a first flexible thermal conductive film 200, a second flexible thermal conductive film 300, and a sealed interlayer 500. The heating element 100 is disposed on the first flexible thermal conductive film 200, and the first flexible thermal conductive film 200 encloses a first accommodating cavity; the second flexible thermal conductive film 300 is disposed within the first accommodating cavity, and the second flexible thermal conductive film 300 encloses a second accommodating cavity. A phase change material 400 is filled within the second flexible thermal conductive film 300, and the phase change material 400 is used to store and release heat; the sealed interlayer 500 is disposed between the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300, and the sealed interlayer 500 is filled with a thermal management liquid. The thermal management liquid can undergo a phase change when heated to transfer the heat of the sealed interlayer 500, and further transfer the heat of the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300.

[0030] Specifically, a part of the heat generated by the heating element 100 of the thermal management system of the present invention is dissipated in the form of thermal radiation through the first flexible thermal conductive film 200, and another part is transferred to the phase change material 400 for storage through the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300. During the non-operating cycle of the heating element 100, the phase change material 400 releases the stored heat. The released heat is transferred to the first flexible thermal conductive film 200 through the second flexible thermal conductive film 300 and dissipated in the form of thermal radiation. A sealed interlayer 500 is disposed between the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300, and filled with a thermal management liquid. The thermal management liquid is heated to become a thermal management vapor. The heat generated by the heating element 100 is transferred between the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300 through the thermal management vapor, thereby improving the thermal conductivity of the flexible thermal conductive material.

[0031] More specifically, the heating element 100 may be, but is not limited to, a spacecraft chip.

[0032] Specifically, the environment of deep space exploration is complex. High-energy particles and rays in cosmic space can penetrate the shielding layer of a spacecraft and generate radiation effects with internal components. The encapsulation housing of the heat dissipation system will face problems such as atomic oxygen corrosion, high-energy particle radiation charging and discharging, corona discharge, and material damage at extreme temperatures in the space environment. These inducements will ultimately lead to the failure of polyimide insulating materials and cause spacecraft failures. Therefore, the first flexible thermal conductive film 200 is a modified polyimide film, and the modified materials are radiation shielding elements, radiation-resistant elements, anti-corona materials, and atomic oxygen-resistant elements. The first flexible thermal conductive film 200 has the characteristics of being resistant to atomic oxygen erosion, high temperature gradient, anti-corona, and radiation resistance. The thickness of the first flexible thermal conductive film 200 is 0.2 mm.

[0033] Furthermore, the radiation shielding elements include at least one of lead, barium, and boron;

[0034] The radiation-resistant elements include at least one of graphene or carbon nanotubes;

[0035] The corona-resistant material includes Al 2 O 3 , TiO 2 and SiO 2 at least one of them;

[0036] The atomic oxygen-resistant elements include at least one of silicon and phosphorus.

[0037] Specifically, the second flexible heat-conducting film 300 is also a modified polyimide film, and the modifying materials are micro-nano particles of water and its oxides, metal nanowires, non-metal oxide particles, graphene, carbon nanotubes or carbon fibers, so that the second flexible heat-conducting film 300 has a high heat-conducting coefficient. The second flexible heat-conducting film 300 is used to conduct the heat of the heating element 100 into the phase-change material 400 for storage, and the thickness of the second flexible heat-conducting film 300 is 0.2 mm.

[0038] Reference Figure 2 and Figure 3 , in some embodiments, the top view of the phase-change material 400 is a square with a side length of 10.8 mm, the thickness of the deformation material is 1 - 1.5 mm, the top view of the second flexible heat-conducting film 300 is a square with a side length of 11 mm, and the height is 1 mm. Reserving the size difference between the phase-change material 400 and the second flexible heat-conducting film 300 can prevent the problems of flow and leakage caused by the phase change of the phase-change material 400 due to heat absorption. Further, the top view of the thermal management system is a square with a side length of 25 mm, and the height is 2 - 3 mm.

[0039] The thermal management system of the present invention has the advantages of small volume, good flexibility, high heat dissipation efficiency and strong radiation resistance, and can be used for the thermal management requirements of spacecraft chips.

[0040] In some embodiments, the sealing sandwich 500 includes a liquid absorption core 510. The liquid absorption core 510 is arranged between the first flexible heat-conducting film 200 and the second flexible heat-conducting film 300. The liquid absorption core 510 has a plurality of capillary channels, and the thermal management liquid circulates in the plurality of capillary channels.

[0041] Specifically, the sealing sandwich 500 is a vacuum seal.

[0042] In some embodiments, the liquid absorption core 510 includes one of a polyethylene polymer film, a polytetrafluoroethylene polymer film and a polypropylene polymer film.

[0043] In some embodiments, the thickness of the wick 510 is 0.05 to 0.1 mm. Specifically, the wick 510 is fixed to the vacuum side of the first flexible heat-conducting film 200 by means of high-temperature bonding. More specifically, a hydrophilic wick 510 is fixed on the vacuum side of the first flexible heat-conducting film 200. The wick 510 has good flexibility and capillary performance, can timely transport the heat management liquid, and improves the heat dissipation capacity of the heat management system under high heat flux density.

[0044] In some embodiments, the sealing sandwich 500 further includes a support mesh 520. The support mesh 520 is disposed between the first flexible heat-conducting film 200 and the second flexible heat-conducting film 300 and is used to support the first flexible heat-conducting film 200 and the second flexible heat-conducting film 300.

[0045] Specifically, the support mesh 520 provides a transmission space for the heat management steam. The support mesh 520 has support lines in a cylindrical spiral shape, which can prevent the deformation of the phase change material 400 region and the collapse of the heat management system.

[0046] More specifically, the support mesh 520 is made of a hydrophobic material.

[0047] Specifically, the wick 510 and the support mesh 520 are disposed between the first flexible heat-conducting film 200 and the second flexible heat-conducting film 300. The wick 510 is disposed on the side close to the first flexible heat-conducting film 200, and the support mesh 520 is disposed on the side close to the second flexible heat-conducting film 300.

[0048] Reference Figure 2 , in some embodiments, the first flexible heat-conducting film 200 is wrapped outside the phase change material 400 encapsulated by four second flexible heat-conducting films 300, and the reserved gap is filled with the support mesh 520.

[0049] In some embodiments, the phase change material 400 is at least one alkane (paraffin) with 14 to 30 carbon atoms.

[0050] In some embodiments, the phase change temperature of the phase change material 400 is 5.5 to 65.5 °C.

[0051] Specifically, the phase change material 400 is modified by nanoparticles, which can improve the latent heat of phase change of the phase change material 400 while enhancing the thermal conductivity of the phase change material 400, facilitating efficient heat management. Specifically, the modifying material is nanoparticles with high thermal conductivity, such as metal nanowires, non-metal oxide nanoparticles, graphene, carbon nanotubes, expanded graphite, etc. The thickness of the phase change material 400 is 1 to 1.5 mm. At the same time, the nanoparticles have an adsorption property for paraffin, can increase the adsorption sites of paraffin, reduce the fluidity of paraffin after melting, can prevent the phase change material 400 from absorbing heat and expanding and leaking, and also solve the problem that the nanomaterials are prone to sedimentation under gravity conditions.

[0052] Specifically, for the heating element 100 with a size of 10 mm × 10 mm, the floor area of the thermal management system is not greater than 30 mm × 30 mm, and the thickness ≤ 3 mm.

[0053] The targeted thermal management system has the characteristics of flexibility and heat storage. At the same time, the space in the thickness direction is limited. The phase change material 400 presents a flat shape. At the same time, the thermal conductivity of polyimide and paraffin is small, resulting in the problem of difficulty in quickly transferring the heat of the heating element 100 to paraffin. The thermal management system of the present invention utilizes the sandwich structure of polyimide films (the first flexible thermal conductive film 200 and the second flexible thermal conductive film 300), which not only ensures the functions of temperature uniformity and flexible packaging, but also enables the heating element 100 to operate in a stable environment.

[0054] In some embodiments, the thermal management liquid includes at least one of deionized water, methanol, ethanol, and fluorinated liquid. Specifically, the liquid filling rate of the thermal management liquid in the sealed sandwich 500 is about 30%.

[0055] Specifically, the fluorinated liquid is preferably FC-72 and HFE-7100.

[0056] In some embodiments, the pressure in the sealed sandwich 500 ≤ 10 Pa.

[0057] In some embodiments, the heating element 100 is fixed to the first flexible thermal conductive film 200 by bonding or 3D printing.

[0058] The heat conduction mechanism of the present invention:

[0059] During the working cycle of the heating element 100, heat is generated. The first flexible heat-conducting film 200 is in direct contact with the heating element 100. The heat management liquid in the sealed sandwich layer 500 undergoes a phase change when heated. The generated heat management steam flows along the hydrophobic support mesh 520, transferring a part of the heat from the hot end (i.e., the end close to the heating element 100) to the cold end (i.e., the end far from the heating element 100), and dissipating it by radiation. Another part of the heat that is not dissipated is introduced into the phase change material 400 through the second flexible heat-conducting film 300 and stored. During the non-working cycle of the heating element 100, the temperature of the phase change material 400 is higher than that of the second flexible heat-conducting film 300 due to the stored heat. Therefore, the stored heat is transferred back to the first flexible heat-conducting film 200 through the second flexible heat-conducting film 300 and dissipated, thus realizing the periodic heat dissipation of the heat management system. In addition, the phase change material 400 is divided and encapsulated in the second flexible heat-conducting film 300, which not only increases the steam passage (i.e., increases the distribution of the support mesh 520), but also increases the contact area between the phase change material 400 and the heat management steam, improving the heat conduction performance and temperature uniformity effect of the heat management system. It solves the problem that the heat of the flexible material polyimide is difficult to quickly transfer to the paraffin when directly encapsulating the paraffin with the flexible material polyimide, and realizes three-dimensional rapid heat conduction.

[0060] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0061] The above embodiments only represent several implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A thermal management system for dissipating heat from a heating element, characterized in that, it comprises: a first flexible heat-conducting film, the heating element is disposed on the first flexible heat-conducting film, the first flexible heat-conducting film encloses a first accommodating cavity, the first flexible heat-conducting film is a modified polyimide film, and the modifying material of the first flexible heat-conducting film is a radiation shielding element, a radiation-resistant element, a corona-resistant material and an atomic oxygen-resistant element; a second flexible heat-conducting film, the second flexible heat-conducting film is disposed in the first accommodating cavity, the second flexible heat-conducting film encloses a second accommodating cavity, and a phase change material is filled in the second accommodating cavity, the phase change material is used for storing and releasing heat, the second flexible heat-conducting film is a modified polyimide film, and the modifying material of the second flexible heat-conducting film is micro-nano particles of water and its oxides, metal nanowires, non-metal oxide particles, graphene, carbon nanotubes or carbon fibers; and a sealing interlayer, the sealing interlayer is disposed between the first flexible heat-conducting film and the second flexible heat-conducting film, and a thermal management liquid is filled in the sealing interlayer, and the thermal management liquid can undergo a phase change when heated to transfer the heat of the sealing interlayer, and further transfer the heat of the first flexible heat-conducting film and the second flexible heat-conducting film.

2. The thermal management system according to claim 1, characterized in that, the sealing interlayer includes a liquid absorption core, the liquid absorption core is disposed between the first flexible heat-conducting film and the second flexible heat-conducting film, the liquid absorption core has a plurality of capillary channels, and the thermal management liquid circulates in the plurality of capillary channels.

3. The thermal management system according to claim 2, characterized in that, the liquid absorption core includes one of a polyethylene polymer film, a polytetrafluoroethylene polymer film and a polypropylene polymer film.

4. The thermal management system according to claim 2, characterized in that, the thickness of the liquid absorption core is 0.05 - 0.1 mm.

5. The thermal management system according to claim 1, characterized in that, the sealing interlayer further includes a support mesh, the support mesh is disposed between the first flexible heat-conducting film and the second flexible heat-conducting film, and is used for supporting the first flexible heat-conducting film and the second flexible heat-conducting film.

6. The thermal management system according to claim 1, characterized in that, the phase change material is at least one alkane having 14 - 30 carbon atoms.

7. The thermal management system according to claim 1, characterized in that, the phase change temperature of the phase change material is 5.5 - 65.5 °C.

8. The thermal management system according to claim 1, characterized in that, the thermal management liquid includes at least one of deionized water, methanol, ethanol and a fluorinated liquid.

9. The thermal management system according to claim 1, characterized in that, the pressure in the sealing interlayer ≤ 10 Pa.

10. The thermal management system according to claim 1, characterized in that, the heating element is fixed to the first flexible heat-conducting film by bonding or 3D printing.

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