High-thermal-conductivity graphene heat-conducting cable and preparation method thereof

Abstract

The invention relates to the technical field of heat conduction materials, and particularly discloses a high-heat-conductivity graphene heat conduction cable and a preparation method thereof.The high-heat-conductivity graphene heat conduction cable comprises a strip-shaped flexible heat conduction belt and metal components welded to the two ends of the flexible heat conduction belt and used for being connected with a heating device; the heat conductivity of the flexible heat conduction belt is 500-2500W / (m.K); the flexible heat conduction belt is formed by stacking and connecting a plurality of graphene heat conduction sheets, and the graphene heat conduction sheets comprise modified graphene, nanometer aluminum oxide particles and nanometer silicon carbide particles. The modified graphene is obtained by modifying graphene oxide with a liquid crystal modifier. According to the high-thermal-conductivity graphene heat-conducting cable, the structure of the single-layer graphene heat-conducting layer is optimized while the problem of connection of the multiple graphene heat-conducting layers is solved, and the thermal conductivity of the single-layer graphene heat-conducting layer in the longitudinal direction and the transverse direction is improved; moreover, the graphene heat-conducting layer is combined with the metal component, so that the use scene of the heat-conducting cable is enlarged, and the applicability of the heat-conducting cable is effectively improved.

Description

Technical Field

[0001] This invention relates to the technical field of thermally conductive materials, and in particular to a high thermal conductivity graphene thermal cable and its preparation method. Background Technology

[0002] With the development of society and technology, electronic components are widely used in our work, production and life. Electronic components emit heat when they are working. In order to maintain the normal and stable operation of each component, it is necessary to transfer the heat to a low-temperature cold source through high thermal conductivity products.

[0003] Currently, traditional thermal conductive products, such as channel heat pipes and copper heat conduction cables, have thermal conductivity that needs improvement. Furthermore, these products are limited by their rigidity and are difficult to bend, which restricts their application scenarios. Therefore, it is necessary to provide a flexible thermal conductive product with high thermal conductivity. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a high thermal conductivity graphene thermal cable that is unaffected by rigidity and thermal conductivity, possesses flexibility and high thermal conductivity efficiency, and a method for its preparation.

[0005] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0006] A high thermal conductivity graphene heat-conducting cable includes a strip-shaped flexible heat-conducting cable and metal components welded to both ends of the flexible heat-conducting cable for connection with a heating device; the thermal conductivity of the flexible heat-conducting cable is 500-2500 W / (m·K).

[0007] The flexible heat-conducting tape is formed by stacking and connecting several graphene heat-conducting sheets. The raw materials of the graphene heat-conducting sheets include modified graphene, nano-alumina particles, and nano-silicon carbide particles. The modified graphene is obtained by modifying graphene oxide with a liquid crystal modifier.

[0008] Furthermore, the preparation method of the graphene thermal conductive sheet includes the following steps: adding 75 to 95 parts by weight of modified graphene to anhydrous ethanol and stirring to obtain a suspension; electrostatically spraying the suspension onto a metal substrate; peeling it off in water; and reducing it to graphene sheets at 2000°C.

[0009] Then, graphene sheets, 1-3 parts of nano-alumina particles and 1-5 parts of nano-silicon carbide particles are mixed and mechanically pressed at 100°C to obtain graphene thermal conductive sheets.

[0010] Furthermore, the preparation method of the flexible heat-conducting tape includes the following steps: after the graphene heat-conducting sheet is purified, it is corona treated for 3 seconds, and then the end of the graphene heat-conducting sheet is welded with solder A at a welding speed of 30 cm / min and a wire feeding speed of 3.5 m / min under conditions of humidity of 50% to 80% and temperature of 40 to 60°C to obtain the flexible heat-conducting tape.

[0011] The solder A is any one of Zn-58Bi-5Cu, Sn-9Ag-Zn, and Sn-3Ag-0.5Cu.

[0012] Furthermore, the modified graphene is prepared by the following method: graphene oxide and liquid crystal modifier are mixed in a weight ratio of 1:(1-2), stirred at 50°C for 1 hour, and then dried to obtain modified graphene.

[0013] Furthermore, the liquid crystal modifier is composed of any two of liquid crystal modifier A, liquid crystal modifier B, and liquid crystal modifier C in a 1:1 weight ratio.

[0014] The structural formula of the liquid crystal modifier A is as follows:

[0015]

[0016] The structural formula of the liquid crystal modifier B is as follows:

[0017]

[0018] The structural formula of the liquid crystal modifier C is as follows:

[0019]

[0020] Furthermore, the graphene oxide is composed of 1 to 3 layers of monolayer graphene oxide, and the graphene oxide has a particle size of 30 to 80 micrometers and an oxygen content of 6%.

[0021] Furthermore, the alumina nanoparticles have a particle size of 20–100 nm and a specific surface area of ​​230–500 m². 2 / g.

[0022] Furthermore, the nano-sized silicon carbide particles have a particle size of 20-100 nm, a thermal conductivity of 200-500 W / (m·K), and an expansion coefficient of 1×10⁻⁶. -6 K -1 ~5×10 -6 K -1 .

[0023] Furthermore, the metal component is any one of aluminum, copper, Al-1.75Fe-1.25Ni, Al-9Si-3Cu, and Al-Si-10Mn-Mg.

[0024] A method for preparing the above-mentioned high thermal conductivity graphene heat-conducting cable is characterized by the following steps: firstly, the two ends of the flexible heat-conducting cable and the welding joint of the metal component are cleaned; then, under the conditions of humidity 40% to 70% and temperature 20 to 60°C, the graphene heat-conducting cable is obtained by welding with solder B at a welding speed of 60 cm / min and a wire feeding speed of 5.0 m / min.

[0025] The solder B is any one of Bi2Te2.9Se0.1, Sn-3Ag-0.5Cu, or MWCNT / In–Sn–Bi.

[0026] Compared with the prior art, the present invention has the following technical effects:

[0027] This invention employs a series of graphene thermal conductive sheets stacked and connected to form a flexible thermal conductive tape. This flexible thermal conductive tape is then combined with metal components to obtain a high thermal conductivity graphene thermal conductive cable. Graphene possesses excellent strength, toughness, and thermal conductivity, which further enhances the strength, toughness, and thermal conductivity of the flexible thermal conductive tape. The thermal conductivity of the flexible thermal conductive tape reaches 500–2500 W / (m·K). This allows the high thermal conductivity graphene thermal conductive cable to possess both strength and flexibility, and it can also be welded to the metal solder joints of various electronic components via metal components. Compared to traditional rigid channel heat pipes, copper thermal conductive cables, and other thermal conductive products, the high thermal conductivity graphene thermal conductive cable disclosed in this invention is not limited by rigidity, can be bent, and possesses superior thermal conductivity, thereby effectively expanding the application scenarios of the thermal conductive cable and significantly improving its applicability.

[0028] Furthermore, the raw materials for the graphene thermal conductive sheet are modified graphene, nano-alumina particles, and nano-silicon carbide particles. The modified graphene is obtained by modifying graphene oxide with a liquid crystal modifier. Modifying graphene oxide with a liquid crystal modifier effectively improves the thermal conductivity of the modified graphene in both the longitudinal and transverse directions. The addition of nano-alumina particles and nano-silicon carbide particles further enhances the strength and thermal conductivity of the graphene thermal conductive sheet. Thus, the graphene thermal conductive sheet in this invention uses modified graphene, nano-alumina particles, and nano-silicon carbide particles as raw materials, effectively improving the thermal conductivity of the graphene thermal conductive sheet in both the longitudinal and transverse directions, thereby further improving the thermal conductivity and strength of the high-thermal-conductivity graphene thermal conductive cable.

[0029] In summary, this invention solves the connection problem of multilayer graphene thermal conductive layers while optimizing the structure of single-layer graphene thermal conductive layers, thereby improving the thermal conductivity of single-layer graphene thermal conductive layers in both the longitudinal and transverse directions. Furthermore, by combining graphene thermal conductive layers with metal components, this invention expands the application scenarios of thermal conductive cables and effectively improves their applicability. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a high thermal conductivity graphene heat-conducting cable according to an embodiment of the present invention;

[0031] Figure 2 Tensile test diagrams of the flexible conductive tape in the high thermal conductivity graphene thermal cables prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0032] Explanation of reference numerals in the attached diagram: 1. Metal component; 2. Solder B; 3. Graphene thermal conductive sheet. Detailed Implementation

[0033] In this invention, the flexible conductive tape has a thickness of 10–250 μm, a length of 1–100 cm, a width of 0.5–20 cm, and a density of 1.8–2.7 g / cm³. 3 .

[0034] Preparation example of modified graphene

[0035] Preparation Example 1

[0036] A method for preparing modified graphene includes the following steps:

[0037] Graphene oxide and liquid crystal modifier were mixed in a weight ratio of 1:1, stirred at 50°C for 1 hour, and then dried at 90°C for 6 hours in a drying oven to obtain modified graphene. The liquid crystal modifier was obtained by mixing liquid crystal modifier A and liquid crystal modifier B in a weight ratio of 1:1.

[0038] Preparation Example 2

[0039] A method for preparing modified graphene includes the following steps:

[0040] Graphene oxide and liquid crystal modifier were mixed in a weight ratio of 1:1.5, stirred at 50°C for 1 hour, and then dried at 90°C for 6 hours in a drying oven to obtain modified graphene. The liquid crystal modifier was obtained by mixing liquid crystal modifier A and liquid crystal modifier C in a weight ratio of 1:1.

[0041] Preparation Example 3

[0042] A method for preparing modified graphene includes the following steps:

[0043] Graphene oxide and liquid crystal modifier were mixed in a mass ratio of 1:2, stirred at 50°C for 1 hour, and then dried at 90°C for 6 hours in a drying oven to obtain modified graphene. The liquid crystal modifier was obtained by mixing liquid crystal modifier B and liquid crystal modifier C in a weight ratio of 1:1.

[0044] Example of graphene thermal conductive sheet preparation

[0045] Preparation Example 4

[0046] A method for preparing a graphene thermal conductive sheet includes the following steps:

[0047] 75 parts by weight of the modified graphene prepared by the method in Preparation Example 1 were added to anhydrous ethanol and stirred at room temperature for 3 hours to obtain a suspension. The suspension was then electrostatically sprayed onto a metal substrate, peeled off in water, and reduced to graphene sheets at 2000°C.

[0048] A graphene thermal conductive sheet is obtained by mixing graphene sheets, 1 part of nano-alumina particles and 1 part of nano-silicon carbide particles, and then mechanically pressing the mixture at 100°C.

[0049] Preparation Example 5

[0050] A method for preparing a graphene thermal conductive sheet includes the following steps:

[0051] 85 parts by weight of the modified graphene prepared by the method in Preparation Example 2 were added to anhydrous ethanol and stirred at room temperature for 3 hours to obtain a suspension. The suspension was then electrostatically sprayed onto a metal substrate, peeled off in water, and reduced to graphene sheets at 2000°C.

[0052] Graphene sheets, 2 parts of nano-alumina particles and 3 parts of nano-silicon carbide particles are mixed and then mechanically pressed at 100°C to obtain graphene thermal conductive sheets.

[0053] Preparation Example 6

[0054] A method for preparing a graphene thermal conductive sheet includes the following steps:

[0055] 95 parts by weight of the modified graphene prepared by the method in Preparation Example 3 were added to anhydrous ethanol and stirred at room temperature for 3 hours to obtain a suspension. The suspension was then electrostatically sprayed onto a metal substrate, peeled off in water, and reduced to graphene sheets at 2000°C.

[0056] A graphene thermal conductive sheet is obtained by mixing graphene sheets, 3 parts of nano-alumina particles and 5 parts of nano-silicon carbide particles and then mechanically pressing them at 100°C.

[0057] Example of flexible conductive tape preparation

[0058] Preparation Example 7

[0059] A method for preparing a flexible conductive tape includes the following steps:

[0060] The graphene thermal conductive sheet prepared by the method in Preparation Example 4 was purified and then subjected to corona treatment for 3 seconds to make the graphene surface clean and have an electrostatic film. Then, at a humidity of 50% and a temperature of 40°C, the end of the graphene thermal conductive sheet was welded with solder A at a welding speed of 30 cm / min and a wire feed speed of 3.5 m / min to obtain a flexible thermal conductive sheet. Solder A is Sn-9Ag-Zn.

[0061] Preparation Example 8

[0062] A method for preparing a flexible conductive tape includes the following steps:

[0063] The graphene thermal conductive sheet prepared by the method in Preparation Example 5 was purified and then corona-treated for 3 seconds to make the graphene surface clean and have an electrostatic film. Then, at a humidity of 65% and a temperature of 50°C, the end of the graphene thermal conductive sheet was welded with solder A at a welding speed of 30 cm / min and a wire feed speed of 3.5 m / min to obtain a flexible thermal conductive sheet. Solder A is Zn-58Bi-5Cu.

[0064] Preparation Example 9

[0065] A method for preparing a flexible conductive tape includes the following steps:

[0066] The graphene thermal conductive sheet prepared by the method in Preparation Example 6 was purified and then corona treated for 3 seconds to make the graphene surface clean and have an electrostatic film. Then, at a humidity of 80% and a temperature of 60°C, the end of the graphene thermal conductive sheet was welded with solder A at a welding speed of 30 cm / min and a wire feed speed of 3.5 m / min to obtain a flexible thermal conductive sheet. Solder A is Sn-3Ag-0.5Cu.

[0067] Example

[0068] Example 1

[0069] A method for preparing a high thermal conductivity graphene thermal cable includes the following steps:

[0070] First, the ends of the flexible conductive tape prepared by the method in Preparation Example 7 and the welded joints of the metal components were cleaned. Then, under the conditions of 40% humidity and 20°C, the graphene heat-conducting cable was obtained by welding with solder B at a welding speed of 60 cm / min and a wire feeding speed of 5.0 m / min.

[0071] The metal components are obtained by SPS sintering aluminum at 580℃, holding the temperature for 10 minutes during the sintering process, and then cooling it with the furnace; the solder B is Bi2Te2.9Se0.1.

[0072] Example 2

[0073] A method for preparing a high thermal conductivity graphene thermal cable includes the following steps:

[0074] First, the ends of the flexible conductive tape prepared by the method in Preparation Example 8 and the weld joint of the metal component were cleaned. Then, under the conditions of 55% humidity and 40°C, the graphene heat-conducting cable was obtained by welding with solder B at a welding speed of 60 cm / min and a wire feeding speed of 5.0 m / min.

[0075] The metal components are obtained by SPS sintering aluminum at 580℃, holding the temperature for 10 minutes during the sintering process, and then cooling it with the furnace; the solder B is Sn-3Ag-0.5Cu.

[0076] Example 3

[0077] A method for preparing a high thermal conductivity graphene thermal cable includes the following steps:

[0078] First, the flexible conductive tape prepared by the method in Preparation Example 9 and the welded joints of the metal components were cleaned. Then, under the conditions of 70% humidity and 60°C, the graphene heat-conducting cable was obtained by welding with solder B at a welding speed of 60 cm / min and a wire feeding speed of 5.0 m / min.

[0079] The metal components are obtained by SPS sintering aluminum at 580℃, holding the temperature for 10 minutes during the sintering process, and then cooling it with the furnace; the solder B is MWCNT / In–Sn–Bi.

[0080] Comparative Example

[0081] Comparative Example 1

[0082] A method for preparing a high thermal conductivity graphene thermal conductive cable is carried out according to the method in Example 1, except that when preparing the graphene thermal conductive sheet, the graphene sheets are replaced by an equal weight of nano-alumina and nano-silicon carbide in the raw material, that is, the raw material does not contain nano-alumina and nano-silicon carbide.

[0083] Comparative Example 2

[0084] A method for preparing a high thermal conductivity graphene thermal conductive cable is carried out according to the method in Example 1, except that when preparing the graphene thermal conductive sheet, the weight of nano-alumina in the raw material is replaced with nano-silicon carbide particles, that is, the raw material does not contain nano-alumina.

[0085] Comparative Example 3

[0086] A method for preparing a high thermal conductivity graphene thermal conductive cable is carried out according to the method in Example 1, except that when preparing the graphene thermal conductive sheet, the modified graphene in the raw material is replaced by an equal weight of graphene oxide, that is, the graphene oxide in the raw material is not oriented by a liquid crystal modifier.

[0087] Performance testing

[0088] The tensile strength, tensile modulus, operating temperature range, surface thermal conductivity, longitudinal thermal conductivity, and heat flux of the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0089] Table 1:

[0090]

[0091] As can be seen from Table 1, the surface thermal conductivity, longitudinal thermal conductivity, and heat flux of the high thermal conductivity graphene heat conduction cables in Examples 1-3 of the present invention are all much greater than those of the high thermal conductivity graphene heat conduction cables in Comparative Examples 1-3. This indicates that the high thermal conductivity graphene heat conduction cables prepared by the preparation method of the present invention have higher thermal conductivity.

[0092] at the same time, Figure 1 This is a schematic diagram of a high thermal conductivity graphene heat-conducting cable according to an embodiment of the present invention. The present invention uses several graphene heat-conducting sheets stacked and connected to form a flexible heat-conducting tape, and then combines the flexible heat-conducting tape with metal components, which increases the application scenarios of the heat-conducting cable and effectively improves the applicability of the heat-conducting cable.

[0093] Figure 2 These are tensile test images of the flexible heating tape in the high thermal conductivity graphene thermal cables prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention. Figure 2 It can be seen that, compared with Comparative Examples 1-3, the tensile stress of Examples 1-3 of the present invention is significantly higher than that of Comparative Examples 1-3; indicating that the high thermal conductivity graphene heat-conducting cable of the present invention has higher tensile strength, and compared with traditional heat-conducting cables, it is not affected by rigidity and can be better applied.

[0094] Thus, it can be shown that the high thermal conductivity graphene thermal cable prepared by the method of the present invention is not affected by rigidity and thermal conductivity, and has flexibility and high thermal conductivity efficiency, thereby meeting the requirements for flexibility and cooling of thermal conductive materials under certain specific conditions.

Claims

1. A high thermal conductivity graphene thermal cable, characterized in that: It includes a strip-shaped flexible conductive tape and metal components welded to both ends of the flexible conductive tape for connection with a heating device; the thermal conductivity of the flexible conductive tape is 500-2500 W / (m·K); The flexible heat-conducting tape is formed by stacking and connecting several graphene heat-conducting sheets. The raw materials of the graphene heat-conducting sheets include modified graphene, nano-alumina particles, and nano-silicon carbide particles. The modified graphene is obtained by modifying graphene oxide with a liquid crystal modifier.

2. The high thermal conductivity graphene thermal cable as described in claim 1, characterized in that, The preparation method of the graphene thermal conductive sheet includes the following steps: 70-95 parts by weight of modified graphene are added to anhydrous ethanol and stirred to obtain a suspension. The suspension is electrostatically sprayed onto a metal substrate, peeled off in water, and reduced to graphene sheets at 2000°C. Then, graphene sheets, 1-3 parts of nano-alumina particles and 1-5 parts of nano-silicon carbide particles are mixed and mechanically pressed at 100°C to obtain graphene thermal conductive sheets.

3. A high thermal conductivity graphene thermal cable as described in claim 1 or 2, characterized in that, The preparation method of the flexible heat-conducting tape includes the following steps: after the graphene heat-conducting sheet is purified, it is corona treated for 3 seconds, and then the end of the graphene heat-conducting sheet is welded with solder A at a welding speed of 30 cm / min and a wire feeding speed of 3.5 m / min under the conditions of humidity of 50% to 80% and temperature of 40 to 60°C to obtain the flexible heat-conducting tape. The solder A is any one of Zn-58Bi-5Cu, Sn-9Ag-Zn, and Sn-3Ag-0.5Cu.

4. The high thermal conductivity graphene thermal cable as described in claim 1, characterized in that, The modified graphene was prepared by the following method: graphene oxide and liquid crystal modifier were mixed in a weight ratio of 1:(1~2), stirred at 50°C for 1 hour, and then dried to obtain modified graphene.

5. A high thermal conductivity graphene thermal cable as described in claim 1 or 4, characterized in that, The liquid crystal modifier is composed of any two of liquid crystal modifier A, liquid crystal modifier B, and liquid crystal modifier C in a 1:1 weight ratio. The structural formula of the liquid crystal modifier A is as follows: The structural formula of the liquid crystal modifier B is as follows: The structural formula of the liquid crystal modifier C is as follows:

6. A high thermal conductivity graphene thermal cable as described in claim 1 or 4, characterized in that, The graphene oxide is composed of 1 to 3 layers of monolayer graphene oxide, and the particle size of the graphene oxide is 30 to 80 micrometers and the oxygen content is 6%.

7. A high thermal conductivity graphene thermal cable as described in claim 1 or 4, characterized in that, The alumina nanoparticles have a particle size of 20–100 nm and a specific surface area of ​​230–500 m². 2 / g.

8. A high thermal conductivity graphene thermal cable as described in claim 1 or 4, characterized in that, The silicon carbide nanoparticles have a particle size of 20-100 nm, a thermal conductivity of 200-500 W / (m·K), and an expansion coefficient of 1×10⁻⁶. -6 K -1 ~5×10 -6 K -1 .

9. The high thermal conductivity graphene thermal cable as described in claim 1, characterized in that, The metal component is any one of aluminum, copper, Al-1.75Fe-1.25Ni, Al-9Si-3Cu, and Al-Si-10Mn-Mg.

10. A method for preparing a high thermal conductivity graphene thermal cable as described in any one of claims 1-9, characterized in that, Includes the following steps: First, the ends of the flexible conductive tape and the welding joints of the metal components are cleaned. Then, under the conditions of humidity 40% to 70% and temperature 20 to 60℃, the graphene heat-conducting cable is obtained by welding with solder B at a welding speed of 60 cm / min and a wire feeding speed of 5.0 m / min. The solder B is any one of Bi2Te2.9Se0.1, Sn-3Ag-0.5Cu, or MWCNT / In–Sn–Bi.

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