Flexible graphene film heat-conducting cable and preparation method thereof

Abstract

The invention belongs to the technical field of graphite metal composite heat dissipation devices, and provides a flexible graphene film heat conduction cable and a preparation method thereof.The preparation method comprises the steps that the surface of a graphene film is cleaned and punched, and the graphene film with micron-sized pores in the surface is obtained; sequentially plating a layer of active metal film and a layer of heat-conducting metal film on the surface of the graphene film, and cutting to obtain a graphene film; graphene films are overlaid layer by layer to obtain a laminated material, and the two ends of the laminated material are clamped to a hot-pressing mold to be subjected to hot-pressing welding treatment, so that a locally connected flexible heat conduction section is obtained; and the flexible heat conduction section and the heat conduction metal shell are assembled, a soldering lug is placed for brazing and finish machining, and the flexible graphene film heat conduction cable is obtained. According to the method, the internal connection problem of the flexible section is solved by establishing a synergistic process of surface punching, double-layer coating and hot pressing, the heterogeneous connection problem of the flexible section and the shell is solved in a manner of sampling coating and brazing, and through the synergistic effect of all links, the overall performance and reliability of the heat-conducting cable are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the technical field of graphite-metal composite heat dissipation devices, and relates to a flexible graphene film heat-conducting cable and its preparation method. Background Technology

[0002] With the rapid development of aerospace technology, the power consumption of individual electronic components inside spacecraft is constantly increasing, and electronic devices are becoming increasingly dense. High power, high integration, and compact structures cause a surge in heat generation from mobile high-power chips inside spacecraft products, leading to prominent overheating problems that severely affect the operational stability and lifespan of the devices. In particular, imaging chips inside spacecraft not only generate a large amount of heat but also require heat dissipation components to have flexible and bendable characteristics to adapt to complex installation environments and dynamic connection requirements. Therefore, a high thermal conductivity, lightweight, and flexible thermal conductive device (heat cable) is needed to achieve efficient heat transfer between heat-generating devices and heat sinks.

[0003] Traditional heat-conducting cables often use braided strips or foil layers of oxygen-free copper or aluminum alloy filaments. However, pure metal heat-conducting cables can no longer meet the ever-increasing heat dissipation demands. Carbon materials rely on phonon heat transfer and possess excellent thermal conductivity, with a theoretical thermal conductivity reaching 5300 W / (m·K). In particular, macroscopic carbon materials such as graphene thermal conductive films and artificial graphite films have in-plane thermal conductivity reaching 1500 W / (m·K), which is more than 3.5 times that of copper. Due to its strong bending resistance and light weight, graphite film has become one of the ideal materials for the flexible segments of heat-conducting cables.

[0004] To achieve higher heat transfer, heat-conducting cables need to possess high heat flux and good flexibility. This requires a relatively thin single-layer graphite heat-conducting film to leverage its flexibility, while simultaneously increasing the overall heat flux by stacking multiple layers of graphite heat-conducting films. However, the ends of the multi-layer flexible heat-conducting cable need to be bonded together and then encapsulated in metal shells at both ends. Currently available heat-conducting cables generally employ the following processes to bond the multi-layer graphite films: Lamination process: Direct mechanical stacking results in high interlayer thermal resistance of graphite films and easy slippage between graphite films, making it difficult to achieve the theoretical assembly amount, ultimately leading to a significant decrease in the heat flux of flexible heat-conducting tape.

[0005] Adhesive bonding process: Organic adhesive occupies a certain volume, which will reduce the amount of film and increase the contact thermal resistance between graphite films, resulting in performance that deviates significantly from the theoretical value.

[0006] Brazing process: Compared to other processes, it reduces the longitudinal interface thermal resistance, but the addition of excessive solder increases the difficulty of the process. The gaseous products generated during the welding process are difficult to remove, which can easily cause solder residue and porosity, resulting in weakened interface bonding strength, reduced thermal conductivity, and reduced product quality.

[0007] Furthermore, achieving a reliable connection with high strength and low thermal resistance between the flexible graphite segments and the rigid metal shell is also a technical challenge. Currently, there are typical heat-conducting cable solutions on the market, such as the graphite heat-conducting cable disclosed in Chinese patent CN109640586A, which achieves connection by depositing a Ti / Mo / Ni film on the graphite film surface and using vacuum brazing. However, this method does not solve the problems of sliding and longitudinal thermal resistance when multiple graphite films are stacked, and its coating system is mainly used for brazing wetting, which differs from the functionally oriented design of this invention: "active metal film + thermally conductive metal film + longitudinal thermally conductive pillar / positioning pillar".

[0008] Therefore, developing a flexible heat-conducting cable preparation method that can simultaneously solve the problems of "low film content and high longitudinal thermal resistance" and "poor connection strength with metal shell" of multilayer graphite films is of great practical significance. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a flexible graphene film heat-conducting cable and its preparation method. This method innovatively employs a synergistic process of "surface perforation + double-layer coating + hot pressing," effectively solving the key challenge of multi-layer graphene film stacking, and achieving a reliable connection with a metal casing through brazing.

[0010] The method for preparing flexible graphene film heat-conducting cables provided by this invention includes the following steps: S1. Clean the surface of the graphene film and perform a perforation process to obtain a graphene film with micron-sized pores on the surface. S2. A layer of active metal film and a layer of thermally conductive metal film are sequentially deposited on the surface of a graphene film with micron-sized pores, and the graphene film is cut to meet the design dimensions of the thermal cable. S3. Graphene films are stacked layer by layer according to the thickness requirements of the heat-conducting cable to obtain a laminated material. The two ends of the laminated material are clamped onto a hot press mold and placed in a vacuum hot press furnace to perform hot press welding on the two ends of the laminated material to obtain a partially connected flexible heat-conducting section. S4. Assemble the flexible heat-conducting section with the heat-conducting metal shell, place welding pads at the welding parts of the heat-conducting metal shell for brazing and finishing, and obtain a flexible graphene film heat-conducting cable.

[0011] Furthermore, micron-sized pores with a diameter of 0.1~1.0 mm and a depth of 0.005~0.020 mm are formed on the surface of the graphene film by means of needle punching, laser drilling or chemical oxidation. The micron-sized pores are blind pores.

[0012] Furthermore, the surface coating treatment is performed by magnetron sputtering or chemical deposition, wherein the active metal film is an element or alloy of titanium, chromium, zirconium, molybdenum or vanadium, and the thermally conductive metal film is an element or alloy of copper, aluminum, silver or gold.

[0013] Furthermore, the thickness of the active metal film is less than that of the thermally conductive metal film, and the total thickness of the active metal film and the thermally conductive metal film is 400-1200 nm.

[0014] Furthermore, the parameters for hot-press welding include: vacuum hot-press temperature of 500~900℃, pressure of 3~20MPa, and vacuum degree >10. -3 Pa·m / s.

[0015] Furthermore, the heat-conducting metal shell is an aluminum alloy shell, and the metal shell contains metal pillars for positioning and longitudinal heat conduction. The solder pad is an aluminum-silicon solder pad or an aluminum-magnesium solder pad, the thickness of the solder pad is 0.010~0.050mm, and the welding temperature is the softening temperature of the solder pad.

[0016] Furthermore, the graphene film is a graphene thermally conductive film or an artificial graphene film with a thickness of 0.020~0.080 mm.

[0017] Furthermore, a layer of copper foil is disposed on the outer surfaces of both the top and bottom layers of the laminated material.

[0018] The flexible graphene film heat-conducting cable provided by this invention is obtained by the above-described preparation method and includes a flexible segment and a heat-conducting metal shell.

[0019] The flexible segment is formed by stacking multiple layers of graphene films, including a wedge structure with hot-pressed ends and a layered structure in the middle. Each layer of graphene film has micron-sized pores, and each layer of graphene film is sequentially coated with an active metal film and a thermally conductive metal film. The thermally conductive metal shell is assembled to the outside of the wedge structure by brazing, and the metal shell contains metal pillars for positioning and longitudinal heat transfer.

[0020] Furthermore, a layer of copper foil is disposed on the outer surface of both the top and bottom layers of the flexible heat-conducting section.

[0021] Compared with existing technologies, this invention has the following outstanding advantages, the core of which lies in constructing a highly efficient, low-resistance, and reliable heat transfer channel: 1. A heat transfer mechanism within the flexible segment, characterized by "drag reduction and locking," was established: The "locking" mechanism: By forming micron-sized pores on the surface of the graphene film, during the hot-pressing process at the ends of the stacked materials, the active metal film and the thermally conductive metal film on the surface of the graphene film material undergo plastic flow under high temperature and pressure, forming a "wedge structure" at the pores of adjacent layers. This structure acts like a "lock," mechanically locking the multilayer graphene film, effectively preventing interlayer slippage and ensuring a high film coverage.

[0022] "Drag Reduction" Mechanism: The wedge-shaped structure formed by hot pressing establishes a direct physical connection between layers, providing a "thermal bridge" across the layers for heat transfer, significantly reducing the longitudinal interface thermal resistance of the flexible heat-conducting cable. Longitudinal metal pillars are set at the junction of the flexible heat-conducting cable and the metal (hot end, heat sink), providing longitudinal heat conduction and positioning, significantly increasing the heat transfer capacity between the hot spot and the heat-conducting cable, as well as between the heat sink and the heat-conducting cable.

[0023] 2. A "metallurgical bonding" mechanism for joining heterogeneous materials was established, achieving strong bonding: The active metal film provides an ideal "welding substrate" for subsequent hot-press welding. The active metal film (such as Ti, Cr, etc.) can react with carbon atoms at high temperatures to form stable carbides (such as TiC, Cr3C2), creating a "metallurgical bond" between graphite and metal. This fundamentally solves the problems of poor wettability and weak bonding between graphite and metal. Through hot-press bonding, the chemical reaction between the active metal and carbon is activated at high temperatures, promoting carbide formation and atomic diffusion, resulting in a stronger bond.

[0024] Thermally conductive metal films (such as Cu, Ag, etc.) are "thermal pads" laid on top of active metal films, which effectively reduces the thermal resistance of the entire interface. Through brazing, molten solder forms a continuous metallurgical bond between the thermally conductive metal film and the metal shell. This connection method has a much higher strength than mechanical pressing or adhesive bonding, and the interface is dense and continuous with extremely low thermal resistance, ensuring efficient heat transfer between the flexible section and the rigid shell and the overall structural reliability.

[0025] 3. In this invention, only the two ends are heat-pressed together, rather than the entire section is heat-pressed together, thus avoiding extensive processing of the entire flexible section and preserving the macroscopic flexibility of the heat-conducting cable to the maximum extent.

[0026] 4. The metal joint is encapsulated by brazing, and the flexible heat-conducting cable is connected to the metal joint simultaneously, which greatly improves the heat conduction capacity and enhances the overall structural strength of the heat-conducting cable.

[0027] 5. By connecting the flexible heat-conducting cable and the metal joint to the flexible heat-conducting cable, the processing of heat-conducting cables of any shape can be realized, which reduces the complex part design caused by assembly difficulty and also greatly ensures the integrity of the graphite film and the continuity of the heat transfer path.

[0028] Tests have shown that the flexible graphene thermal conductive cable prepared by the method of this invention has bendability, an equivalent thermal conductivity ≥1000W / (m·K), and a temperature difference of 26℃ between the hot and cold ends when a 20W heat source is applied to the hot end.

[0029] In summary, this invention solves the internal connection problem of the flexible segment through a synergistic process of "surface drilling + double-layer coating + hot pressing", and then solves the heterogeneous connection problem with the shell through "coating + brazing". The synergistic effect of each link results in a heat-conducting cable with the advantages of high graphite film coverage, strong heat transfer capacity and excellent impact and vibration resistance, which significantly improves the overall performance and reliability of the heat-conducting cable. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of the preparation method of the flexible graphene film heat-conducting cable in this invention; Figure 2 This is a schematic diagram of the flexible graphene film heat-conducting cable in this invention. Detailed Implementation

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0033] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The drawings only show components related to this disclosure and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0035] This invention provides a method for preparing a flexible graphene film thermal conductive cable, see [link to relevant documentation]. Figure 1 As shown, the preparation method includes the following steps: S1. Clean the surface of the graphene film and perform a perforation process to obtain a graphene film with micron-sized pores on the surface. S2. A layer of active metal film and a layer of thermally conductive metal film are sequentially deposited on the surface of a graphene film with micron-sized pores, and the graphene film is cut to meet the design dimensions of the thermal cable. S3. Graphene films are stacked layer by layer according to the thickness requirements of the heat-conducting cable to obtain a laminated material. The two ends of the laminated material are clamped onto a hot press mold and placed in a vacuum hot press furnace to perform hot press welding on the two ends of the laminated material to obtain a partially connected flexible heat-conducting section. S4. Assemble the flexible heat-conducting section with the heat-conducting metal shell, place welding pads at the welding parts of the heat-conducting metal shell for brazing and finishing, and obtain a flexible graphene film heat-conducting cable.

[0036] In one embodiment, the graphene film is a graphene thermally conductive film or an artificial graphene film with a thickness of 0.020~0.080 mm.

[0037] In one embodiment, micron-sized pores with a diameter of 0.1~1.0 mm and a depth of 0.005~0.020 mm are formed on the surface of the graphene film using methods such as needle punching, laser drilling, or chemical oxidation. These micron-sized pores are blind pores. During implementation, the pore size and depth can be adjusted by the needle tip thickness and force, or by the laser power and the number of strikes.

[0038] By forming micron-sized pores on the surface of the graphene film, a heat transfer path within the flexible segment was established through a synergistic "drag reduction and locking" mechanism. The locking mechanism involves the plastic flow of the active and thermally conductive metal films on the graphene film surface during hot-pressing at the ends of the stacked materials under high temperature and pressure. This results in the formation of a "wedge-shaped structure" at the micron-sized pores on the surfaces of adjacent graphene layers. This structure acts like a "lock," mechanically locking the multilayer graphene film and effectively preventing interlayer slippage, thus ensuring a high film coverage. The drag reduction mechanism involves the wedge-shaped structure formed by hot pressing establishing direct physical connections between layers, providing a "thermal bridge" across the layers for heat transfer and significantly reducing longitudinal interfacial thermal resistance.

[0039] In one embodiment, since the graphite film surface is smooth and difficult to adhere, the present invention deposits a metal that readily reacts with carbon materials onto the graphite film surface, making the graphite film layers more tightly bonded and reducing interfacial thermal resistance. For example, metals such as nickel and titanium readily form compounds with carbon materials, which can activate the graphite film surface. Therefore, a thin nickel or titanium layer is generally deposited on the graphite film surface. Metals such as gold, silver, and copper have high thermal conductivity, which can reduce the thermal resistance between graphite film layers, while simultaneously achieving the fusion of the graphite layer with the flexible thermally conductive upper and lower protective copper layers. In implementation, surface coating treatment can be performed using magnetron sputtering or chemical deposition. The active metal film is an element or alloy of titanium, chromium, zirconium, molybdenum, or vanadium, and the thermally conductive metal film is an element or alloy of copper, aluminum, silver, or gold.

[0040] In one embodiment, the thickness of the active metal film is less than that of the thermally conductive metal film, and the total thickness of the active metal film and the thermally conductive metal film is 400-1200 nm.

[0041] In one embodiment, the parameters for hot-press welding include: vacuum hot-press temperature of 500~900℃, pressure of 3~20MPa, and vacuum degree >10. -3 Pa·m / s. During hot pressing, only the two ends of the laminated material are hot-pressed, rather than the entire material is hot-pressed together. This avoids extensive processing of the entire flexible section, thus preserving the macroscopic flexibility of the heat-conducting cable to the maximum extent.

[0042] In one embodiment, see Figure 2 As shown, one end of the laminated material is the heat sink end, and the other end is the heating element end. Both ends use aluminum as the encapsulation shell, and the metal shell contains metal pillars for positioning and longitudinal heat conduction. To achieve excellent welding performance with the metal shell, the solder pads used in this invention are all aluminum-based solder pads, aluminum-silicon solder pads, or aluminum-magnesium solder pads. The thickness of the solder pads is 0.010~0.050mm, and the welding temperature is the softening temperature of the solder pads.

[0043] In one embodiment, a copper foil layer with a thickness of 0.010~0.080 nm is disposed on the outer surfaces of both the top and bottom layers of the laminated material. The copper foil serves as a protective layer for the graphite film. The stacked materials are uniformly loaded into a hot pressing mold and placed in a vacuum hot pressing furnace for welding to obtain locally connected flexible heat-conducting sections. The vacuum hot pressing temperature is 500~900℃, the pressure is 3-20MPa, and the vacuum degree is better than 10. -3 Pa·m / s.

[0044] The flexible graphene film heat-conducting cable provided by this invention is obtained using the above-described preparation method. See [link to relevant documentation]. Figure 2 As shown, the flexible graphene film heat-conducting cable includes a flexible segment, and heat-conducting metal shells are welded to both ends of the flexible segment.

[0045] The flexible segment is formed by stacking multiple layers of graphene films, including a wedge structure with hot-pressed ends and a layered structure in the middle. Each layer of graphene film has micron-sized pores, and each layer of graphene film is sequentially coated with an active metal film and a thermally conductive metal film. The thermally conductive metal shell is assembled to the outside of the wedge structure by brazing, and the metal shell contains metal pillars for positioning and longitudinal heat transfer.

[0046] In one embodiment, a copper foil is disposed on the outer surface of both the top and bottom layers of the flexible thermally conductive section.

[0047] The advantages of the flexible graphene film heat-conducting cable method prepared in this invention are illustrated by the following Examples 1 to 5 and Comparative Examples 1 to 3: Example 1: Step 1: Clean the graphene film surface with alcohol / acetone and perform surface oxidation treatment to obtain a rough graphite film with a thickness of 0.040 mm.

[0048] Step 2, the surface roughening process can be surface oxidation. The cleaned graphene film is placed in an air atmosphere and kept at a temperature of 200℃ for 80 minutes to obtain a graphene film with micron-sized pores with a surface pore size of 0.2mm and a depth of 0.010mm.

[0049] Step 3: The obtained rough graphite film is subjected to surface magnetron sputtering coating treatment, with an active titanium film and a thermally conductive copper film deposited in sequence. The graphene film is then cut to meet the design dimensions of the thermal cable. The thickness of the active titanium film is 50 nm and the thickness of the thermally conductive copper film is 200 nm. The graphene film is then cut to the required size.

[0050] Step 4: Stack the surface-treated graphite film layer by layer according to the required thickness of the heat-conducting cable. Place a copper foil layer on the top and bottom layers. The copper foil has a thickness of 0.010 nm and serves as a protective layer for the graphite film. Put the stacked materials into a hot press mold and place them in a vacuum hot press furnace for welding to obtain a connected flexible heat-conducting section. The vacuum hot press temperature is 650℃, the pressure is 10MPa, and the vacuum degree is better than 10-3Pa·m / s. Step 5: Assemble and fasten the flexible heat-conducting section to the aluminum alloy shell, and place aluminum-magnesium welding sheets with a thickness of 0.020mm at the welding parts of the aluminum alloy shell. Place the assembled parts in the brazing furnace, and after the product is heated up with the furnace body, keep it warm and cool to complete the brazing. Step 6: After brazing, the product is precision machined using CNC to obtain the finished heat-conducting cable.

[0051] Example 2: The difference between Example 2 and Example 1 is as follows: the graphite film thickness is 0.050 mm; it undergoes needle punching treatment, resulting in micron-sized pores with a diameter of 0.4 mm and a depth of 0.008 mm; the active metal film is a chromium film with a thickness of 40 nm; the thermally conductive metal film is a copper film with a thickness of 800 nm; the copper foil thickness is 0.050 nm; the solder sheet is an aluminum-magnesium solder sheet with a thickness of 0.01 mm; the vacuum hot pressing temperature is 850℃, the pressure is 20 MPa, and the vacuum degree is better than 10. -3 Pa·m / s.

[0052] Example 3: The difference between Example 3 and Example 1 is as follows: the graphite film thickness is 0.050 mm; it undergoes needle punching treatment, resulting in micron-sized pores with a diameter of 0.4 mm and a depth of 0.008 mm; the active metal film is a chromium film with a thickness of 300 nm; the thermally conductive metal film is a copper film with a thickness of 800 nm; the copper foil thickness is 0.050 nm; the solder sheet is an aluminum-silicon solder sheet with a thickness of 0.01 mm; the vacuum hot pressing temperature is 850℃, the pressure is 20 MPa, and the vacuum degree is better than 10. -3 Pa·m / s.

[0053] Example 4: The difference between Example 4 and Example 1 is as follows: the graphite film thickness is 0.070 mm; it undergoes laser ablation treatment, resulting in micron-sized pores with a diameter of 0.1 mm and a depth of 0.015 mm; the active metal film is a zirconium film with a thickness of 300 nm; the thermally conductive metal film is a silver film with a thickness of 600 nm; the copper foil thickness is 0.020 nm; the solder sheet is an aluminum-magnesium solder sheet with a thickness of 0.01 mm; the vacuum hot pressing temperature is 800℃, the pressure is 15 MPa, and the vacuum degree is better than 10. -3 Pa·m / s.

[0054] Example 5: The difference between Example 5 and Example 1 is as follows: the graphite film thickness is 0.050 mm; surface oxidation treatment is performed, and the cleaned graphene film is placed in an air atmosphere and kept at a temperature of 350°C for 60 minutes; the micron-sized pores have a diameter of 0.1 mm and a depth of 0.015 mm; the active metal film is a vanadium film with a thickness of 30 nm; the thermally conductive metal film is a gold film with a thickness of 500 nm; the copper foil thickness is 0.020 nm; the solder sheet is an aluminum-silicon solder sheet with a thickness of 0.02 mm; the vacuum hot pressing temperature is 900°C, the pressure is 5 MPa, and the vacuum degree is better than 10. -3 Pa·m / s.

[0055] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not undergo coating treatment and is directly stacked and hot-pressed.

[0056] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the coated graphite film is directly assembled without hot pressing.

[0057] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that micron-sized pores are not prepared on the surface of the graphite film.

[0058] The flexible graphene film heat-conducting cables prepared by Examples 1 to 5 and Comparative Examples 1 to 3 were tested for the number of films and the temperature difference. The test results are shown in Table 1 below: Table 1: Performance Test Table of Flexible Graphene Film Thermal Conductive Cable

[0059] The results in Table 1 above show that the flexible graphene film heat-conducting cables prepared by the method of this invention have a higher film coverage (calculated based on film thickness) than the comparative examples, and their temperature uniformity is also superior. This demonstrates the importance of surface roughening, surface coating, and integrated molding of the flexible strip to the performance of the heat-conducting cable products (corresponding to the comparison results of Example 1 and Comparative Examples 1-3, respectively). In the examples, surface roughening enhances the bonding force between graphite film layers, surface coating is matched with a hot-pressing process to achieve integrated molding of the flexible heat-conducting tape, and the metal shell is equipped with positioning posts to increase assembly accuracy and longitudinal thermal conductivity, significantly increasing the film coverage and improving the heat uniformity of the heat-conducting cable.

[0060] Furthermore, by comparing Examples 1 to 5, it can be seen that the roughening process, the type of coating metal, and the coating thickness also have a significant impact on the performance of the heat conduction cable.

[0061] Obviously, those skilled in the art should understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations of the embodiments of the present invention are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method of making a flexible graphene film heat conducting cable, characterized by, The application relates to a graphene film heat-conducting cable. The graphene film surface is cleaned and punched to obtain a graphene film with micron-level pores on the surface; An active metal film and a heat-conductive metal film are sequentially plated on the graphene film surface with micron-level pores, and a graphene film satisfying the design size of the heat-conductive cable is obtained by cutting; According to the thickness requirement of the heat-conductive cable, the graphene films are stacked layer by layer to obtain a laminated material, the two ends of the laminated material are clamped to a hot-pressing die, and the two ends of the laminated material are subjected to hot-pressing welding treatment in a vacuum hot-pressing furnace to obtain a flexible heat-conductive section with local connection; The flexible heat-conductive section is assembled with a heat-conductive metal shell, a soldering sheet is placed at the welding position of the heat-conductive metal shell for brazing and finishing, and a flexible graphene film heat-conductive cable is obtained.

2. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: Micron-level pores with a diameter of 0.1-1.0 mm and a depth of 0.005-0.020 mm are formed on the graphene film surface by needle punching, laser punching or chemical oxidation, and the micron-level pores are blind holes.

3. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: Surface film plating treatment is carried out by magnetron sputtering or chemical plating, the active metal film is a single element or an alloy of titanium, chromium, zirconium, molybdenum or vanadium, and the heat-conductive metal film is a single element or an alloy of copper, aluminum, silver or gold.

4. The method of claim 3, wherein the flexible graphene film heat conducting cable is prepared by the steps of: The thickness of the active metal film is smaller than that of the heat-conductive metal film, and the total thickness of the active metal film and the heat-conductive metal film is 400-1200 nm.

5. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: The parameters of the hot press welding treatment include: vacuum hot press temperature of 500-900℃, pressure of 3-20 MPa, vacuum degree >10 -3 Pa·m / s.

6. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: The heat-conductive metal shell is an aluminum alloy shell, and the metal shell is provided with a metal column for positioning and longitudinal heat conduction. The soldering sheet is an aluminum-silicon soldering sheet or an aluminum-magnesium soldering sheet, the thickness of the soldering sheet is 0.010-0.050 mm, and the welding temperature is the softening temperature of the soldering sheet.

7. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: The graphene film is a graphene heat-conductive film or an artificial graphite film, and the thickness is 0.020-0.080 mm.

8. The method of claim 1, wherein the flexible graphene film heat conducting cable is prepared by the steps of: A copper foil is arranged outside the top layer and the bottom layer of the laminated material.

9. A flexible graphene film heat conducting cord prepared by the method of any one of claims 1 to 7, characterized in that, The graphene film heat-conductive cable comprises a flexible section and a heat-conductive metal shell, the flexible section is formed by stacking a plurality of graphene films, comprises a contractile structure with end hot-pressing welding and a middle layer structure, wherein micron-level pores are arranged on each graphene film, and an active metal film and a heat-conductive metal film are sequentially plated on the surface of each graphene film; the heat-conductive metal shell is assembled outside the contractile structure by brazing, and the metal shell is provided with a metal column for positioning and longitudinal heat conduction.

10. The flexible graphene film heat conducting cable of claim 9, wherein, A copper foil is arranged outside the top layer and the bottom layer of the flexible heat-conductive section.

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