Preparation method of graphene micro-nano cavity heat conduction film containing micro-channels and graphene tim film and heat dissipation system

Abstract

The application discloses a graphene micro-nano cavity heat-conducting film containing micro-channels, a preparation method of a graphene TIM film and a heat dissipation system, and relates to the field of heat management. The graphene micro-nano cavity heat-conducting film containing micro-channels is formed by embedding PBO fibers in a graphene oxide coating film and completely burning and volatilizing the PBO fibers in a subsequent heat treatment process. The graphene micro-nano cavity heat-conducting film is stacked and vertically arranged and bonded into a graphene square, and then is cut in a direction parallel to the coating direction to obtain a graphene TIM film containing micro-channels and having high longitudinal heat conductivity. The TIM film is combined with an immersion water cooling heat dissipation system to realize a new heat dissipation system of a heat interface material directional heat conduction, heat conduction into micro-channels, and three-stage heat conduction of channel fluid convection heat removal.

Description

Technical Field

[0001] This invention relates to the field of thermal management, and more particularly to the preparation method and heat dissipation system of graphene micro-nano cavity thermal conductive film and graphene TIM film containing microchannels. Background Technology

[0002] With the promotion and popularization of 5G communication technology, heat dissipation has become a common problem in electronic devices. High-performance processors and sensors in intelligent machines (such as robots, autonomous driving equipment, and AI servers) generate a lot of heat during operation. Insufficient heat dissipation can lead to thermal throttling, reducing computing speed and real-time response capabilities.

[0003] Microchannel (hydraulic diameter 1μm≤d≤200μm) heat sinks have attracted much attention due to their excellent heat dissipation capabilities. They offer advantages such as high thermal efficiency, compact structure, and ease of system-level integration. Compared to traditional cooling channels, microchannels have a larger heat transfer area and a thinner thermal boundary layer within the same volume, resulting in stronger heat transfer performance to meet the high heat flux density requirements of chips. Their small size aligns with the trend of chip miniaturization. Through parameter and structural optimization, heat transfer efficiency and temperature uniformity can be balanced, flow pressure drop can be reduced, and they can also work in conjunction with embedded cooling to achieve efficient heat dissipation near the heat source.

[0004] Graphene possesses a strong covalent bond structure and low phonon scattering rate, which is beneficial for efficient heat transfer via phonons. The in-plane thermal conductivity of ideal monolayer graphene can reach 3000-5300 W / (m·K) at room temperature, making it one of the materials with the best known thermal conductivity. This extremely high thermal conductivity significantly improves the heat exchange efficiency in microchannels and enables rapid heat transfer from the heat source region. Furthermore, graphene exhibits extremely high heat resistance and excellent thermal stability, making it ideal for extreme high-temperature environments, thereby improving the reliability and lifespan of microchannel cooling systems. Summary of the Invention

[0005] To address one or more technical problems, the first objective of this application is to provide a method for fabricating a microchannel-based thermal interface material, which combines microchannels with a thermal interface material to construct microchannels within the thermal interface material, specifically including the following steps: 1) Mix graphene oxide cake with deionized water until homogeneous to prepare graphene oxide slurry with a solid content of 2wt% ~ 8wt%.

[0006] 2) Place the coating substrate on the coating machine, lay the PBO fibers flat on the coating substrate without contacting the surface of the coating substrate, and then coat the graphene oxide slurry on the coating substrate. The coating thickness is greater than the diameter of the PBO fibers and completely covers the PBO fibers. After drying, a graphene oxide film is obtained.

[0007] 3) At room temperature, the graphene oxide film is immersed in a foaming agent for chemical reduction treatment, and then naturally dried to obtain a graphene foamed film.

[0008] 4) The graphene foamed film is subjected to thermal reduction treatment to obtain a graphene micro-nano cavity thermal conductive film containing microchannels inside.

[0009] In a further technical solution, the coating substrate includes one or more of polyimide film (PI), polyethylene terephthalate (PET), and polypropylene (PP).

[0010] In a further technical solution, the diameter of the PBO fiber is set to 10um to 30um.

[0011] In a further technical solution, in step 2), the coating direction is set to the Y direction, the direction perpendicular to the coating direction is set to the X direction, and the thickness direction of the film is set to the Z direction. Multiple PBO fibers are arranged along the Y direction. Alternatively, multiple PBO fibers are arranged along both the Y and Z directions.

[0012] In a further technical solution, in step 2), before coating, the two ends of the PBO fiber are respectively fixed at the limiting blocks located at the beginning and end of the coating substrate, so that the PBO fiber remains fixed during the coating process.

[0013] In a further technical solution, in step 2), the coating thickness is set to 0.5mm ~ 4mm, the coating thickness is greater than the diameter of the PBO fiber and completely covers the PBO fiber.

[0014] In a further technical solution, the coating speed of the graphene oxide slurry is 5 mm / s to 60 mm / s, preferably 10 mm / s to 40 mm / s.

[0015] In a further technical solution, in step 3), the foaming agent is a hydrazine hydrate solution with a mass concentration of 10% to 80%.

[0016] In a further technical solution, step 4) includes pretreatment, carbonization, and graphitization. The pretreatment involves heating to 200-270℃ and holding at each temperature for 30-120 minutes, with a heating rate of 0.3-1℃ / min. The carbonization temperature is 800-1400℃, with a heating rate of 1-4℃ / min, and the temperature is raised to a preset point and held for 0.5-2 hours. The graphitization process is then performed at 2500-3200℃ for 1 hour. After the thermal reduction treatment, the PBO fibers completely burn and volatilize, forming microchannels in the space they originally occupied, thus obtaining a graphene micro / nano cavity thermally conductive film containing microchannels.

[0017] Another objective of this invention is to provide a graphene TIM film containing internal microchannels. This is achieved by longitudinally arranging graphene micro / nano cavity thermally conductive films containing internal microchannels to prepare a graphene TIM film that combines both longitudinal and lateral thermal conductivity. The specific preparation method includes the following steps: taking a graphene micro / nano cavity thermally conductive film containing internal microchannels, and stacking the graphene micro / nano cavity thermally conductive film into a graphene cube of a predetermined height. Immersing the graphene cube in a carbon-based binder, and then performing a thermal reduction treatment. Cutting the thermally reduced graphene cube along the stacking direction, with the cutting direction parallel to the coating direction and avoiding the microchannels. After cutting, a graphene TIM film containing internal microchannels and exhibiting high longitudinal thermal conductivity is obtained.

[0018] In a further technical solution, the carbon-based binder is selected as a graphene oxide aqueous slurry with a solid content of 2wt% to 8wt%.

[0019] In a further technical solution, before soaking in the carbon-based binder, the graphene block is perforated along the stacking direction, avoiding the location of the microchannels during the perforation process.

[0020] A third objective of this invention is to provide a heat dissipation system comprising a micropump providing a power source, a sealing unit serving as a sealing connection device, a finned heat sink serving as a heat dissipation device, and a thermal interface material filling the space between the finned heat sink and the chip, wherein the thermal interface material is a graphene TIM film containing microchannels. The sealing unit communicates with the microchannels inside the graphene TIM film, and the micropump is connected to the sealing unit to deliver external coolant into the microchannels.

[0021] In a further technical solution, the sealing unit includes a cavity module and a Luer connector, which are connected by a hose. The cavity module is used to contain coolant and create a pressure difference. The Luer connector communicates with the microchannels inside the graphene TIM membrane, ensuring that coolant can flow between the sealing unit and the microchannels.

[0022] In a further technical solution, the cooling fluid is selected as a fluorinated fluid.

[0023] In a further technical solution, a pad is also provided below the micro pump as a support.

[0024] The advantages of this invention are: Traditional thermal interface materials (TIMs) primarily rely on passive heat dissipation, depending solely on the material's inherent thermal conductivity. When chip power fluctuates dynamically (e.g., load fluctuations in AI chips and GPUs), heat tends to accumulate locally, causing thermal resistance to increase with temperature. Furthermore, chip heat is often concentrated in core computing units (e.g., the CPU / GPU core area). While traditional TIMs can fill interface gaps, they cannot actively guide heat flow; heat in hotspots can only diffuse slowly, easily leading to localized overheating. This invention constructs microchannels within the thermal interface material and uses a micropump to power the circulation of coolant within these microchannels. Heat is first rapidly conducted to the microchannels via the directional heat-conducting TIM, and then carried away by convective heat transfer within the channels. This achieves a three-stage heat conduction process: directional heat conduction by the thermal interface material → heat introduction into the microchannels → convective heat removal within the channels, significantly improving the system's thermal efficiency. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall structure of the heat dissipation system of the present invention; Figure 2 This is a schematic cross-sectional view of the heat dissipation system of the present invention; Figure 3 This is a schematic diagram of the micro pump of the present invention; Figure 4 This is a schematic diagram of the sealing unit of the present invention; Figure 5 This is a partially enlarged view of the sealing module of the present invention; Figure 6 This is a schematic diagram of the connecting pipes of the present invention; Figure 7 This is a schematic diagram of the Luer connector of the present invention; Figure 8 A schematic diagram illustrating the steps of the graphene TIM film stacking and cutting process; Detailed Implementation

[0027] The following detailed description of exemplary embodiments of this application refers to the accompanying drawings, which form part of the description, illustrating exemplary embodiments in which this application may be implemented. The more detailed description of embodiments of this application below is not intended to limit the scope of the claimed application, but is merely illustrative and does not limit the description of the features and characteristics of this application, in order to suggest the best mode for carrying out this application and sufficient to enable those skilled in the art to implement it. However, it should be understood that various modifications and variations can be made without departing from the scope of this application as defined by the appended claims. The detailed description and drawings should be considered illustrative only and not restrictive, and any such modifications and variations shall fall within the scope of this application described herein. Furthermore, the background art is intended to illustrate the current state of research and development and significance of the technology, and is not intended to limit this application or its application areas.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] To facilitate understanding of the technical solution of this application, the technical problem of this application will be described first below.

[0031] Microchannel heat sinks (hydraulic diameter 1 μm ≤ d ≤ 200 μm) have attracted much attention due to their excellent heat dissipation capabilities, offering advantages such as high thermal efficiency, compact structure, and ease of system-level integration. Graphene, as a novel material, possesses a strong covalent bond structure and low phonon scattering rate, which is beneficial for efficient heat transfer via phonons. The in-plane thermal conductivity of ideal monolayer graphene can reach 3000-5300 W / (m·K) at room temperature, making it one of the materials with the best known thermal conductivity. However, a clear method for fabricating graphene into microchannel heat sinks remains elusive.

[0032] Based on this, the present invention mainly provides a technical solution that uses a graphene micro-nano cavity thermal conductive film containing microchannels to prepare a graphene thermal interface material for application in microchannel heat sinks.

[0033] The first aspect of this application provides a method for preparing a graphene micro / nano cavity thermally conductive film containing internal microchannels, specifically including the following steps: 1) Graphene oxide cake is mixed with deionized water and stirred evenly to prepare a graphene oxide aqueous slurry with a solid content of 2wt% to 8wt%. The solid content of the graphene oxide aqueous slurry is typically, but not limited to, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, and 8wt%.

[0034] 2) Place the coating substrate on the coating machine, lay the PBO fibers flat on the coating substrate without contacting the surface of the coating substrate, and then coat the graphene oxide slurry on the coating substrate. The coating thickness is greater than the diameter of the PBO fibers and completely covers the PBO fibers. After drying, a graphene oxide film is obtained.

[0035] 3) At room temperature, the graphene oxide film is immersed in a foaming agent for chemical reduction treatment, and then naturally dried to obtain a graphene foamed film.

[0036] 4) The graphene foamed film is subjected to thermal reduction treatment to obtain a graphene micro-nano cavity thermal conductive film containing microchannels inside.

[0037] In some typical embodiments, the coating substrate is selected from one or more of polyimide film (PI), polyethylene terephthalate (PET), and polypropylene (PP).

[0038] In some typical embodiments, the diameter of the PBO fiber is set to 10 μm to 30 μm. The diameter of the PBO fiber is typically, but not limited to, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and 30 μm.

[0039] In some typical embodiments, in step 2), the coating direction is set to the Y direction, the direction perpendicular to the coating direction is set to the X direction, and the thickness direction of the film is set to the Z direction. Multiple PBO fibers are arranged along the Y direction. Alternatively, multiple PBO fibers are arranged along both the Y and Z directions. The spacing between adjacent PBO fibers along the Y direction is 0.5 mm to 1 mm.

[0040] When multiple PBO fibers are arranged along the Y direction, in step 2), before coating, the two ends of the multiple PBO fibers are fixed parallel and side-by-side to the limiting blocks located at the beginning and end of the coating substrate, so that the PBO fibers remain fixed during the coating process. The spacing between adjacent PBO fibers along the Y direction is 0.5mm to 1mm, and the thickness of the limiting blocks is 0.5mm to 1mm, made of acrylic sheet.

[0041] When multiple PBO fibers are arranged along the Y and Z directions, in step 2), before coating, the two ends of the multiple PBO fibers are fixed parallel and side-by-side to the limiting blocks located at the beginning and end of the coating substrate, respectively, so that the PBO fibers remain fixed during the coating process. Simultaneously, the limiting blocks are stacked in two or more layers, with the layer thickness being less than or equal to the coating thickness. The spacing between adjacent PBO fibers along the Y direction is 0.5mm to 1mm, and the spacing between adjacent PBO fibers along the Z direction is 0.5mm to 1mm.

[0042] In some typical embodiments, in step 2), the coating thickness is set to 0.5 mm to 4 mm, the coating thickness is greater than the diameter of the PBO fiber and completely covers the PBO fiber.

[0043] In some typical embodiments, the coating speed of the graphene oxide slurry is 5 mm / s to 60 mm / s, preferably 10 mm / s to 40 mm / s. The coating speed of the graphene oxide slurry is typically, but not limited to, 10 mm / s, 15 mm / s, 20 mm / s, 23 mm / s, 25 mm / s, 28 mm / s, 30 mm / s, 33 mm / s, 36 mm / s, 38 mm / s, and 40 mm / s.

[0044] In some typical embodiments, in step 3), the foaming agent is a hydrazine hydrate solution with a mass concentration of 10% to 80%. The concentration of the foaming agent is typically, but not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, and 80%.

[0045] In some typical embodiments, step 4) includes pretreatment, carbonization, and graphitization. The pretreatment involves heating to 200-270°C and holding at each temperature for 30-120 minutes, with a heating rate of 0.3-1°C / min. The carbonization temperature is 800-1400°C, with a heating rate of 1-4°C / min, and held at the preset temperature for 0.5-2 hours. The graphitization process is then performed at 2500-3200°C for 1 hour. After the thermal reduction treatment, the PBO fibers completely burn and volatilize, forming microchannels in the previously occupied space, thus obtaining a graphene micro / nano cavity thermally conductive film containing microchannels.

[0046] Another aspect of this application is to provide a method for preparing a graphene TIM film containing internal microchannels. The technical principle is to use graphene micro / nano cavity thermally conductive films containing internal microchannels arranged longitudinally to prepare a graphene TIM film that takes into account both longitudinal and lateral thermal conductivity.

[0047] The specific preparation method includes the following steps: such as Figure 8 As shown, a graphene micro-nano cavity thermal conductive film containing microchannels is taken and stacked into a graphene block of a predetermined height.

[0048] The graphene blocks were immersed in a carbon-based binder, then removed and subjected to thermal reduction treatment. The steps and reaction conditions of the thermal reduction treatment were the same as step 4) of the graphene micro / nano cavity thermal conductive film. The graphene oxide was thermally reduced, and during this process, a continuous reaction involving the thermal removal of oxygen-containing functional groups, the reduction and reconstruction of the carbon framework, and the long-range ordered crystallization of carbon atoms bonded and fixed adjacent graphene micro / nano cavity thermal conductive films.

[0049] The graphene cubes, after thermal reduction treatment, are cut along the stacking direction, such as... Figure 8 As shown, the cutting direction is crucial; the cutting should avoid the location of the microchannels to preserve the integrity of the microchannel structure. After cutting, a graphene TIM film containing internal microchannels and exhibiting high thermal conductivity in the longitudinal direction is obtained.

[0050] In some typical embodiments, the carbon-based binder is selected from graphene oxide aqueous slurry with a solid content of 2wt% to 8wt%. The carbon-based binder is typically, but not limited to, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, and 8wt%.

[0051] In some typical embodiments, the graphene blocks are perforated along the stacking direction before being soaked in a carbon-based binder, avoiding the location of the microchannels during the perforation process.

[0052] The third objective of this application is to provide a heat dissipation system. For example... Figure 1 and Figure 2 As shown, the heat dissipation system includes a micro pump that provides a power source, a sealing unit that serves as a sealing connection device, a finned heat sink that serves as a heat dissipation device, and a thermal interface material that fills the space between the finned heat sink and the chip. The thermal interface material is a graphene TIM film containing microchannels inside.

[0053] The sealing unit is connected to the microchannel inside the graphene TIM membrane, and the micropump is connected to the sealing unit to deliver external cooling liquid into the microchannel.

[0054] In some typical embodiments, the sealing unit includes a cavity module and a Luer connector, which are connected by a hose. The cavity module is used to contain coolant and create a pressure difference. The Luer connector communicates with microchannels inside the graphene TIM membrane, ensuring that coolant can flow between the sealing unit and the microchannels.

[0055] In some typical embodiments, the coolant is a fluorinated liquid.

[0056] In some typical embodiments, a pad serving as a support is also provided below the micropump.

[0057] The following are specific examples of the preparation of graphene TIM films. Example 1

[0058] A method for preparing a graphene TIM film includes the following steps: 1) Mix graphene oxide cake with deionized water until homogeneous to prepare graphene oxide slurry with a solid content of 6wt%.

[0059] 2) Place the PET coating substrate on a coating machine, fix the two ends of several PBO fibers with a diameter of 10μm to the limiting blocks at the front and rear ends of the coating substrate respectively, arrange the PBO fibers in parallel along the coating direction, and the interval between adjacent PBO fibers is 0.5mm. The PBO fibers are laid flat on the coating substrate and do not contact the surface of the coating substrate. Then, the graphene oxide slurry is coated on the coating substrate at a coating speed of 10mm / s and a coating thickness of 0.5mm. The slurry completely covers the PBO fibers. After drying, a graphene oxide film is obtained.

[0060] 3) Under room temperature conditions, the graphene oxide film is immersed in a foaming agent, the foaming agent being a 60% hydrazine hydrate solution. During the immersion process, the graphene oxide film undergoes chemical reduction treatment. After removal, it is naturally dried to obtain a graphene foamed film.

[0061] 4) The graphene foamed film is subjected to thermal reduction treatment to obtain a graphene micro / nano cavity thermal conductive film containing microchannels. The thermal reduction treatment process includes pretreatment, carbonization treatment, and graphitization treatment. The pretreatment involves heating to 270℃ and holding at each temperature point for 50 minutes, with a heating rate of 1℃ / min; the carbonization treatment involves heating to 1400℃ at a heating rate of 4℃ / min and holding at the preset temperature point for 2 hours; the graphitization treatment involves graphitization at 3000℃ and holding for 1 hour. After the thermal reduction treatment, the PBO fibers completely burn, vaporize, and volatilize, forming microchannels in the spaces they originally occupied, thus obtaining a graphene micro / nano cavity thermal conductive film containing microchannels.

[0062] 5) Take the graphene micro-nano cavity thermal conductive film containing microchannels obtained in step 4) and stack the graphene micro-nano cavity thermal conductive film onto a graphene block of a preset height.

[0063] 6) The graphene block is immersed in a carbon-based binder, wherein the carbon-based binder is a graphene oxide aqueous slurry with a solid content of 8 wt%. After removal, it is subjected to thermal reduction treatment. The steps and reaction conditions of the thermal reduction treatment are the same as those in step 4) of the graphene micro / nano cavity thermal conductive film.

[0064] 7) The graphene cubes after thermal reduction treatment are cut along the stacking direction, with the cutting direction parallel to the coating direction (Y direction), avoiding the location of the microchannels and preserving the integrity of the microchannel structure. After cutting, a graphene TIM film containing internal microchannels and exhibiting high thermal conductivity in the longitudinal direction is obtained. Example 2

[0065] 1) A method for preparing a graphene TIM film, comprising the following steps: The graphene oxide cake was mixed with deionized water and stirred evenly to prepare a graphene oxide slurry with a solid content of 6 wt%.

[0066] 2) Place the PET coating substrate on a coating machine, fix the two ends of several PBO fibers with a diameter of 10μm to the limiting blocks at the front and rear ends of the coating substrate respectively, arrange the PBO fibers in parallel along the coating direction, and the interval between adjacent PBO fibers is 0.5mm. The PBO fibers are laid flat on the coating substrate and do not contact the surface of the coating substrate. Then, the graphene oxide slurry is coated on the coating substrate at a coating speed of 10mm / s and a coating thickness of 0.5mm. The slurry completely covers the PBO fibers. After drying, a graphene oxide film is obtained.

[0067] 3) Under room temperature conditions, the graphene oxide film is immersed in a foaming agent, the foaming agent being a 60% hydrazine hydrate solution. During the immersion process, the graphene oxide film undergoes chemical reduction treatment. After removal, it is naturally dried to obtain a graphene foamed film.

[0068] 4) The graphene foamed film is subjected to thermal reduction treatment to obtain a graphene micro / nano cavity thermal conductive film containing microchannels. The thermal reduction treatment process includes pretreatment, carbonization treatment, and graphitization treatment. The pretreatment involves heating to 270℃ and holding at each temperature point for 50 minutes, with a heating rate of 1℃ / min; the carbonization treatment involves heating to 1400℃ at a heating rate of 4℃ / min and holding at the preset temperature point for 2 hours; the graphitization treatment involves graphitization at 3000℃ and holding for 1 hour. After the thermal reduction treatment, the PBO fibers completely burn, vaporize, and volatilize, forming microchannels in the spaces they originally occupied, thus obtaining a graphene micro / nano cavity thermal conductive film containing microchannels.

[0069] 5) Take the graphene micro-nano cavity thermal conductive film containing microchannels obtained in step 4) and stack the graphene micro-nano cavity thermal conductive film onto a graphene block of a preset height.

[0070] 6) Drill holes in the graphene blocks along the stacking direction, avoiding the location of the microchannels during the drilling process.

[0071] 7) The graphene block is immersed in a carbon-based binder, wherein the carbon-based binder is a graphene oxide aqueous slurry with a solid content of 8 wt%. After removal, it is subjected to thermal reduction treatment. The steps and reaction conditions of the thermal reduction treatment are the same as those in step 4) of the graphene micro / nano cavity thermal conductive film.

[0072] 8) The graphene cubes after thermal reduction treatment are cut along the stacking direction, with the cutting direction parallel to the coating direction (Y direction), avoiding the location of the microchannels and preserving the integrity of the microchannel structure. The resulting graphene TIM film contains internal microchannels and exhibits high thermal conductivity in the longitudinal direction. Example 3

[0073] In step 2 of this embodiment, the PET coating substrate is placed on a coating machine, and the two ends of several PBO fibers with a diameter of 10μm are fixed to the limiting blocks at the front and rear ends of the coating substrate, respectively. The PBO fibers are arranged parallel to each other along the coating direction, and the limiting blocks are stacked in two layers along the Z direction. Other steps and process parameters are the same as in embodiment 2. Application Cases

[0074] A heat dissipation system. For example... Figure 1 — Figure 7 As shown, this heat dissipation system includes a micropump 1 providing a power source, and a pad 8 serving as a support below the micropump 1. It also includes a sealing unit as a sealing connection device, a finned heat sink 3 as a heat dissipation device, and a thermal interface material 2 filled between the finned heat sink 3 and the chip 4. The thermal interface material 2 is a graphene TIM film containing microchannels. The sealing unit includes a cavity module 7 and a Luer connector 5, which are connected by a hose 6. The cavity module 7 is used to contain coolant and create a pressure difference. The Luer connector 5 communicates with the microchannels inside the graphene TIM film, ensuring that coolant can flow between the sealing unit and the microchannels.

[0075] The sealing unit is connected to the microchannel inside the graphene TIM membrane, and the micropump 1 is connected to the sealing unit to deliver external cooling liquid into the microchannel.

[0076] During application, the entire system is immersed in a sealed enclosure made of acrylic sheet. The enclosure contains a coolant, specifically a fluorinated liquid, which is ideal as a coolant due to its low viscosity, poor electrical conductivity, and good thermal conductivity. A graphene TIM film is positioned between the chip 4 and the finned heat sink 3, transferring heat from the chip to the finned heat sink for dissipation. During operation, a micro-pump 1 is immersed in the coolant. The left inlet of the micro-pump 1 draws in the coolant, while the right outlet connects to the sealing unit, filling the cavity module 7 of the sealing unit with coolant. This creates a pressure difference between the left and right ends of the thermal interface material. The coolant enters the microchannels of the thermal interface material through the connecting pipe 6 and multiple Luer connectors 5. Under the pressure difference, the coolant flows within the thermal interface material, carrying away heat.

[0077] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0078] The above description describes specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for fabricating a microchannel-based thermal interface material, comprising combining microchannels with a thermal interface material to construct microchannels within the thermal interface material, specifically including the following steps: 1) Mix graphene oxide cake with deionized water until homogeneous to prepare graphene oxide slurry with a solid content of 2wt% ~ 8wt%; 2) Place the coating substrate on the coating machine, lay the PBO fibers flat on the coating substrate without contacting the surface of the coating substrate, and then coat the graphene oxide slurry on the coating substrate. The coating thickness is greater than the diameter of the PBO fibers and completely covers the PBO fibers. After drying, a graphene oxide film is obtained. 3) Under room temperature conditions, the graphene oxide film is immersed in a foaming agent for chemical reduction treatment, and then naturally dried to obtain a graphene foamed film. 4) The graphene foamed film is subjected to thermal reduction treatment to obtain a graphene micro-nano cavity thermal conductive film containing microchannels inside.

2. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: The coating substrate includes one or more of polyimide film (PI), polyethylene terephthalate (PET), and polypropylene (PP).

3. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: The diameter of the PBO fiber is set to 10µm to 30µm.

4. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: The coating direction is set to the Y direction, the perpendicular coating direction is set to the X direction, and the thickness direction of the film is set to the Z direction. Multiple PBO fibers are arranged along the Y direction, or multiple PBO fibers are arranged along both the Y and Z directions.

5. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: In step 2), before coating, the two ends of the PBO fiber are fixed to the limiting blocks located at the beginning and end of the coating substrate, respectively, so that the PBO fiber remains fixed during the coating process.

6. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: In step 2), the coating thickness is set to 0.5mm ~ 4mm, the coating thickness is greater than the diameter of the PBO fiber and completely covers the PBO fiber.

7. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: The coating speed of the graphene oxide slurry is 5 mm / s to 60 mm / s, preferably 10 mm / s to 40 mm / s.

8. The method for preparing a microchannel-based thermal interface material according to claim 1, characterized in that: Step 4) includes pretreatment, carbonization, and graphitization. Pretreatment involves heating to 200-270℃ and holding at each temperature for 30-120 minutes, with a heating rate of 0.3-1℃ / min. Carbonization is performed at 800-1400℃, with a heating rate of 1-4℃ / min, and holding at the preset temperature for 0.5-2 hours. Graphitization is then performed at 2500-3200℃ for 1 hour. After the thermal reduction treatment, the PBO fibers completely burn and volatilize, forming microchannels in the space they originally occupied, thus obtaining a graphene micro / nano cavity thermally conductive film containing microchannels.

9. A method for preparing a graphene TIM film containing microchannels, comprising the following steps: Take the graphene micro-nano cavity thermal conductive film prepared according to any one of claims 1-8, stack the graphene micro-nano cavity thermal conductive film to a graphene block of a preset height, immerse the graphene block in a carbon-based binder, take it out and perform a thermal reduction treatment, cut the graphene block after thermal reduction treatment along the stacking direction, while the cutting direction is parallel to the coating direction and avoids the position of the microchannel, and obtain a graphene TIM film containing microchannels inside and having high thermal conductivity in the longitudinal direction after cutting.

10. A heat dissipation system comprising a micropump providing a power source, a sealing unit serving as a sealing connection device, a finned heat sink serving as a heat dissipation device, and a thermal interface material filling the space between the finned heat sink and the chip, characterized in that: The thermal interface material is the graphene TIM film prepared according to claim 9. The sealing unit is connected to the microchannel inside the graphene TIM film. The micropump is connected to the sealing unit to deliver external cooling liquid into the microchannel.

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