Use of graphene-modified super-property copper in field of high-current device

Abstract

The present invention belongs to the technical field of conductor materials, and provides the use of graphene-modified super-property copper in the field of high-current devices. In the graphene-modified super-property copper provided by the present invention, carbon atoms of graphene are distributed in gaps between copper atoms, this structure enables the copper material to form an extremely strong internal structure, such that the copper material has the properties of low temperature coefficient of resistance, low coefficient of thermal expansion and high current density, and is suitable for devices requiring high current and low temperature, such as electric vehicles (charging / motor / signal), unmanned aerial vehicles, semiconductor electronics as well as national defense and military industrial leads. The graphene-modified super-property copper is a novel conductor material integrating energy conservation, heat reduction, voltage withstand and low price.

Description

Application of graphene super copper in the field of high current devices Technical Field

[0001] The present invention relates to the technical field of conductor materials, and in particular to the application of graphene super copper in the field of high current devices. Background Art

[0002] Since the discovery of electricity, countless scientists have researched and developed its theory and applications. After centuries of hard work, electricity has become indispensable to our lives today. In recent years, electric vehicles and 5G communications have become crucial industry trends. The efficiency of high-frequency signal transmission, power transmission, and electromagnetic conversion is crucial, and conductor materials are crucial for conducting electrical energy and signals.

[0003] To determine whether a material is a good conductor, the International Annealed Copper Standard (IACS) has established a measurement standard, which is the resistivity of pure copper after annealing at 20 degrees Celsius of 1.724×10 -8 The electrical conductivity of (Ω·m) is defined by IACS as 100%, and the resistivity of pure silver, which has a higher conductivity, is 1.626×10 -8 (Ω·m) relative comparison can be calculated to give an electrical conductivity of IACS 106%. Pure silver has the highest electrical conductivity of any natural material.

[0004] Although the conductivity of pure copper is 100%, its resistivity is 1.724×10 -8 (Ω·m), a one-meter-long round copper conductor with a diameter of 2mm has a resistance of 5.48mΩ. When current flows through this copper conductor, power consumption is generated: P = I 2 If a current of 100A flows through it, 10000 × 0.00548 = 54.8W of electrical energy will be lost. This consumed electrical energy will be converted into heat, causing the temperature of the copper conductor to rise. This temperature increase will increase the impedance of the copper conductor, further increasing the power consumption and temperature. This vicious cycle will eventually cause the system to crash, which is called thermal breakdown.

[0005] Therefore, reducing the thermal breakdown problem of copper conductors and reducing the amount of copper material used are issues that need to be urgently addressed in this field.

[0006] Summary of the Invention

[0007] The present invention aims to provide an application of graphene super copper in the field of high-current devices. The graphene super copper has the characteristics of low temperature coefficient of resistance, low thermal expansion coefficient, and high current density. It can be used in high-current devices and can also reduce the thermal breakdown problem of copper conductors and reduce the amount of copper material used.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides an application of graphene super copper in the field of high-current devices. In the graphene super copper, carbon atoms of graphene are distributed in the gaps between copper atoms.

[0010] Preferably, the copper atoms bond with the carbon atoms of the graphene to form metal covalent bonds.

[0011] Preferably, the thermal expansion coefficient of the graphene super copper is less than 15.7 (μm / m·°C) within 200°C.

[0012] Preferably, the high-current device includes an electric vehicle or an AI server.

[0013] Preferably, the high-current device includes an unmanned aerial vehicle, semiconductor electronics, or defense and military wires.

[0014] Preferably, the graphene super copper is used in the form of wire, target, plate, foil or powder.

[0015] Preferably, the graphene super copper is subjected to vacuum melting treatment before use, and the temperature of the vacuum melting is 1100-1500°C.

[0016] The present invention provides an application of graphene super-thermal copper in the field of high-current devices. In the graphene super-thermal copper, graphene carbon atoms are distributed in the gaps between copper atoms. This structure can enable the copper material to have an extremely strong internal structure, resulting in the copper material having the characteristics of low temperature coefficient of resistance, low thermal expansion coefficient, and high current density. The current density of the graphene super-thermal copper is 10-30% higher than that of oxygen-free copper; the temperature coefficient of resistance is 10-30% lower than that of oxygen-free copper. The graphene super-thermal copper is suitable for devices requiring high current and low temperature, such as electric vehicles (charging / motor / signal), drones, semiconductor electronics, and national defense and military wires. The graphene super-thermal copper is a new conductor material that integrates energy saving, heat reduction, voltage resistance, and low cost.

[0017] This invention utilizes graphene-copper super-copper, a composite of graphene and copper, for high-current devices. Testing has shown that super-copper exhibits minimal temperature rise when current flows through it, resulting in a low temperature resistivity. Therefore, it can carry higher currents within a certain temperature range, reducing losses. This improves efficiency and reliability in green energy, electric vehicles, semiconductors, and high-frequency communications, while mitigating the thermal breakdown problem of copper conductors. Consequently, copper usage can be reduced in these applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of the microstructure and morphology of graphene super copper;

[0019] FIG2 is a micro differential scanning calorimetric analysis diagram of general oxygen-free copper;

[0020] FIG3 is a micro differential scanning calorimetry analysis diagram of graphene super copper;

[0021] FIG4 is a Raman spectrum of graphene;

[0022] FIG5 is a Raman spectrum of graphene super copper;

[0023] FIG6 is a comparison of the current-voltage curves of a conventional 4N oxygen-free copper wire (Nippon Cu) and a graphene super-strength copper wire;

[0024] FIG7 is a comparison of the temperature-resistance curves of conventional 4N oxygen-free copper wire (Nippon Cu) and graphene super-strength copper wire;

[0025] FIG8 is a temperature-resistance curve of graphene;

[0026] FIG9 is a graph showing the thermal expansion data of a conventional copper sheet, an oxygen-free copper sheet, and a graphene super copper sheet;

[0027] Figure 10 is a comparison of the temperature rise data of pure copper and graphene super copper. DETAILED DESCRIPTION

[0028] The present invention provides an application of graphene super copper in the field of high-current devices. In the graphene super copper, carbon atoms of graphene are distributed in the gaps between copper atoms.

[0029] In the present invention, the copper atoms and the carbon atoms of the graphene form a metal covalent bond.

[0030] In the present invention, the graphene super copper is preferably prepared according to the method described in Chinese Patent (CN 113073221 B).

[0031] In the present invention, the thermal expansion coefficient of the graphene super copper is less than 15.7 (μm / m·°C) within 200°C.

[0032] In the present invention, the high-current device preferably includes an electric vehicle or an AI server.

[0033] In the present invention, the high-current device preferably includes an unmanned aerial vehicle, semiconductor electronics, or defense and military wires.

[0034] In the present invention, the graphene super copper is preferably used in the form of wire, target, plate, foil or powder.

[0035] In the present invention, the graphene super copper is preferably subjected to vacuum melting treatment before use, and the temperature of the vacuum melting is preferably 1100-1500° C.; the present invention has no special limitation on the time of the vacuum melting, which can be adjusted according to actual needs.

[0036] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1

[0038] In this embodiment, graphene super copper is prepared according to the method described in Chinese patent CN113073221B.

[0039] Performance Testing

[0040] 1) The graphene super copper prepared in Example 1 (the mass proportion of graphene in the super copper is 700 ppm) was vacuum melted at 1500° C. and made into a mother bar with a diameter of 8 mm. The mother bar was tested using an HR TEM high-resolution electron microscope. The results are shown in Figure 1. In Figure 1, a is a schematic diagram of the formation principle of super copper, in which graphene and copper react to form graphene super copper, and b is an electron microscope photograph of graphene super copper. The large white dots are copper atoms and the small white dots are carbon atoms. As shown in Figure 1, graphene super copper is a metal covalent bond alloy material formed by bonding copper atoms and carbon atoms.

[0041] 2) Testing at the National Taiwan University Precious Instrument Center

[0042] The graphene super copper prepared in Example 1 (the mass proportion of graphene in the super copper is 2000ppm) was vacuum smelted at 1500°C and then powdered into a powder with a particle size of 25μm. The powder was subjected to micro-differential scanning calorimetry analysis together with commercially available 4N oxygen-free copper (average particle size 25μm). The results are shown in Figure 2 (4N oxygen-free copper) and Figure 3 (super copper).

[0043] The DSC results in Figure 2 show that graphene super-copper requires greater energy to dissolve, and graphene super-copper has two melting points, which means that the microstructure of super-copper is stronger and the reliability is higher.

[0044] 3) The graphene super-thermal copper prepared in Example 1 was vacuum-melted to 8 mm in thickness and then drawn into 2 mm super-thermal copper wire for Raman spectroscopy. Simultaneously, untreated graphene was subjected to Raman spectroscopy. The results are shown in Figures 4 and 5; the inset in Figure 4 is a partial magnification. Figures 4 and 5 show that the graphene super-thermal copper exhibits the same D and G bonds as graphene.

[0045] 4) The graphene super-hard copper prepared in Example 1 (graphene content in the super-hard copper was 700 ppm by mass) was vacuum-melted at 1500°C and formed into an 8 mm diameter mother bar. This was then drawn into a 50 μm diameter super-hard copper wire. The IV curve and temperature resistance were tested against commercially available Nippon 50 μm copper wire. The results are shown in Figures 6 and 7.

[0046] When current passes through a copper wire, power consumption occurs: P = I 2 R, converted into heat, raises the temperature of the copper conductor and increases its impedance, leading to greater power consumption and higher temperatures. This vicious cycle can cause system collapse, known as thermal collapse. Figures 6-7 show that the graphene super-copper used in the present invention has a lower temperature coefficient than oxygen-free copper, which can increase efficiency. When temperature increases, the resistance of graphene super-copper rises less than that of oxygen-free copper, reducing the risk of thermal collapse, increasing efficiency, and saving power.

[0047] 5) Resistors

[0048] Positive Temperature Coefficient (PTC): This refers to the fact that the resistance of a material increases as the temperature rises. The larger the temperature coefficient, the greater the increase in resistance for the same temperature change.

[0049] Negative Temperature Coefficient (NTC): This refers to a material's resistance decreasing as temperature rises. The resistance of both semiconductors and insulators decreases with increasing temperature. Graphene, semiconductors, and ceramics all exhibit negative temperature coefficients.

[0050] Figure 8 shows the temperature resistance of graphene. Figure 8 is derived from the prior art (Supplementary Information, November 2011. High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network.), showing that graphene has a negative temperature coefficient (NTC) of resistance. The temperature resistance coefficient of pure copper is about 0.0039, while that of graphene super-thermal copper is about 0.0030-0.0033. The temperature coefficient of resistance (TCR) of graphene super-thermal copper is even smaller than that of pure copper.

[0051] 6) The graphene super-strong copper prepared in Example 1 was vacuum-melted into copper ingots, which were then rolled into 0.2 mm super-strong copper sheets. The coefficient of thermal expansion (CTE) was tested against oxygen-free copper sheets (4N copper sheets, 0.2 mm thick) and conventional copper sheets. The results are shown in Figure 9 and Table 1.

[0052] Table 1 Thermal expansion coefficient data of different copper samples

[0053] It can be seen from Table 1 and Figure 9 that at 100-150°C, the thermal expansion coefficient of graphene super-thermal copper is 8.3% lower than that of oxygen-free copper sheet, and at 200-250°C, the thermal expansion coefficient of graphene super-thermal copper is 22.8% lower than that of oxygen-free copper sheet.

[0054] 7) Comparison of current and temperature rise:

[0055] Test materials: 1. Pure copper wire, 128 strands, each strand 0.2mm in diameter;

[0056] 2. The graphene super-copper prepared in Example 1 (the mass proportion of graphene in the super-copper is 700ppm) was vacuum-smelted at 1500°C and made into an 8mm diameter mother rod, which was then drawn into a wire diameter of 0.2mm and twisted with 128 wires. The results are shown in Figure 10 (Comparison of input current (55A / 75A) and temperature of pure copper and super-copper wire) and Table 2.

[0057] Table 2 Temperature rise data of pure copper and graphene super copper

[0058] As shown in Figure 10 and Table 2, at 55A, the temperature of the super-thermal copper dropped by 14°C; at 75A, the temperature of the super-thermal copper dropped by 31°C; the graphene super-thermal copper can pass a larger current in the same cross-sectional area, an increase of 10-20%.

[0059] 8) Fast charging pile test

[0060] Test Materials: 1. Oxygen-free copper wire, 0.2mm diameter per strand, twisted into a fast charging cable;

[0061] 2. The graphene super-thermal copper 700ppm prepared in Example 1 was vacuum melted to 8mm, then stretched to a 0.2mm diameter wire, and then twisted into multiple strands to make a fast charging cable. This was made by the same wire drawing factory, with only the conductor wire replaced with graphene super-thermal copper. The D+ connector remained unchanged (the connector material was the same). The water flow rate and fan speed were each reduced by 50%, and a fast charging cable test was conducted on a 600ADC (direct current) electric vehicle to test the temperature difference between graphene super-thermal copper and 4N copper.

[0062] Limitations: The internal temperature of the wire cannot exceed 125°C; the temperature of the D+ connector cannot exceed 90°C. The results are shown in Table 3.

[0063] Table 3 Fast charging data of 4N copper and graphene super copper

[0064] As shown in Table 3, using graphene super copper as a wire conductor can significantly reduce the temperature and increase the current by about 20%.

[0065] If the D+ terminal material is replaced with graphene super-copper, the fast charging time can be extended. Therefore, graphene super-copper will make it easier to develop 800A and 1000A fast charging in the future.

[0066] 9) Take 20cm of ultra-high-strength copper wire of varying diameters, apply an adjustable current source to both ends, and measure the temperature at the center using a thermocouple. At room temperature (25°C), adjust the current source output until the thermocouple temperature stabilizes at 75°C. This current is the current carrying capacity. The finer the wire diameter, the greater the current density.

[0067] Table 4 Current carrying capacity data of general oxygen-free copper and super copper

[0068] Table 4 shows that graphene super-thermal copper has a significantly higher current carrying capacity than conventional oxygen-free copper of similar wire diameter, and the difference increases with thinner wire diameter. Since current density = current carrying capacity / cross-sectional area, it's clear that graphene super-thermal copper has a significantly higher current density than conventional oxygen-free copper.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An application of graphene super copper in the field of high current devices, characterized in that: In the graphene super copper, the carbon atoms of graphene are distributed in the gaps between copper atoms.

2. The use according to claim 1, characterized in that The copper atoms bond with the carbon atoms of the graphene to form metallic covalent bonds.

3. The use according to claim 1, characterized in that The thermal expansion coefficient of the graphene super copper is less than 15.7 μm / (m·°C) within 200°C.

4. The use according to claim 1, characterized in that The high-current devices include electric vehicles or AI servers.

5. The use according to claim 1, characterized in that The high-current devices include unmanned aerial vehicles, semiconductor electronics or defense and military wires.

6. The use according to claim 1, characterized in that The graphene super copper can be used in the form of wire, target, plate, foil or powder.

7. The use according to any one of claims 1 to 6, characterized in that: The graphene super copper is subjected to vacuum melting treatment before use, and the temperature of the vacuum melting is 1100-1500°C.

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