Use of graphene-enhanced copper in the field of high-current devices

Abstract

This invention provides the use of graphene supercopper in the field of high-current devices and belongs to the field of conductive materials. In the graphene supercopper described in this invention, the carbon atoms of graphene are distributed in the gaps between copper atoms, and this structure allows the copper material to have a very strong internal structure, and it has the characteristics of a low temperature coefficient of resistance, a low coefficient of thermal expansion, and a high current density, making it suitable for devices that require high current and low temperature, such as electric vehicles (charging / motor / signal), drones, semiconductor electronics, and conductors for national defense, military, and industrial applications. The graphene supercopper is a novel conductive material that combines energy saving, heat reduction, high voltage resistance, and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of conductor materials, and particularly to the use of graphene superconducting copper in the field of high-current devices.

Background Art

[0002] Since humans discovered electricity, countless scientists have studied and developed the theory and application of electricity. As a result of centuries of efforts, today's people's lives are impossible without electricity. In recent years, electric vehicles and 5G communications have become very important industrial trends, and the efficiency of high-frequency signal transmission, power transmission, electromagnetic conversion, etc. of electricity has become extremely important factors. Conductor materials that conduct electrical energy and signals are the most important materials.

[0003] To determine whether a material is a good conductor, the International Annealed Copper Standard (abbreviated as IACS) has established measurement criteria. When an annealed pure copper material shows a resistivity of 1.724×10 -8 (Ω·m) at 20 degrees Celsius, its conductivity is defined as IACS 100%. Comparing with the resistivity of pure silver, which is 1.626×10 -8 (Ω·m), it can be calculated that the conductivity is IACS 106%. Pure silver is the substance with the highest conductivity among natural materials.

[0004] The conductivity of pure copper is 100%, and its resistivity is 1.724×10 -8 (Ω·m). As a result of calculating for a 1-meter-long pure copper round wire conductor (diameter 2 mm), the resistance of 1 meter length is 5.48 mΩ. When current passes through this copper wire, the power consumption: P = I 2A resistance (R) is generated. When a current of 100A passes through, 10000 × 0.00548 = 54.8(W) of electrical energy is lost. This consumed electrical energy is converted into thermal energy, raising the temperature of the copper conductor. As the temperature of the copper conductor rises, the impedance of the copper conductor increases, further increasing the power consumption and raising the temperature even more. This vicious cycle eventually leads to the destruction of the system, which is called thermal breakdown.

[0005] Therefore, reducing the problem of thermal fracture in copper conductors and decreasing the amount of copper material used are urgent issues that need to be addressed in this field. [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide the use of graphene-superpolymer copper in the field of high-current devices. The graphene-superpolymer copper has characteristics such as a low temperature coefficient of resistance, a low coefficient of thermal expansion, and a high current density, making it suitable for use in high-current devices. Furthermore, it can reduce the problem of thermal breakdown of copper conductors and reduce the amount of copper material used. [Means for solving the problem]

[0007] To achieve the above-mentioned objectives of the invention, the present invention provides the following technical solutions. This invention provides a method for using graphene supercopper in the field of high-current devices, wherein the carbon atoms of graphene are distributed in the gaps between copper atoms.

[0008] Preferably, the copper atoms and the carbon atoms of graphene bond together, forming a metallic covalent bond.

[0009] Preferably, the thermal expansion coefficient of the graphene-superabsorbent copper is <15.7 μm / (m·℃) at 200℃ or less.

[0010] Preferably, the high-current device includes an electric vehicle or an AI server.

[0011] Preferably, the high-current device includes wires for drones, semiconductor electronics, or defense and military industrial applications.

[0012] Preferably, the form of use of the graphene supercopper includes wire, target material, foil material, or powder.

[0013] Preferably, the graphene supercopper is subjected to a vacuum melting treatment before use, and the vacuum melting process The temperature is between 1100 and 1500°C. [Effects of the Invention]

[0014] This invention provides the use of graphene-super-copper in the field of high-current devices. In graphene-super-copper, the carbon atoms of graphene are distributed in the gaps between copper atoms. This structure allows the copper material to have a very strong internal structure, resulting in a low temperature coefficient of resistance, a low coefficient of thermal expansion, and a high current density. Graphene-super-copper exhibits a 10-30% improvement in current density and a 10-30% reduction in temperature coefficient of resistance compared to oxygen-free copper, making it suitable for devices requiring high current and low temperature, such as electric vehicles (charging / motor / signaling), drones, semiconductor electronics, and military industrial wires. Graphene-super-copper is a novel conductive material that combines energy saving, heat reduction, high voltage resistance, and low cost.

[0015] This invention utilizes graphene-super-copper, a combination of graphene and copper, in high-current devices. Test results show that super-copper exhibits minimal temperature rise during current flow and a low thermal resistance coefficient, allowing for the passage of larger currents within a given temperature range and reducing losses. This improves efficiency and reliability in green energy, electric vehicles, semiconductors, and high-frequency communications, while reducing the thermal breakdown problems associated with copper conductors. Consequently, it becomes possible to reduce the amount of copper material used during application.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram and a morphological diagram of the microstructure of graphene superconducting copper. [Figure 2] It is a micro differential scanning calorimetry analysis diagram of general oxygen-free copper. [Figure 3] It is a micro differential scanning calorimetry analysis diagram of graphene superconducting copper. [Figure 4] It is a Raman spectrum of graphene. [Figure 5] It is a Raman spectrum of graphene superconducting copper. [Figure 6] It is a comparison diagram of the current-voltage curves of general 4N oxygen-free copper wire (Nippon Cu) and graphene superconducting copper wire. [Figure 7] It is a comparison diagram of the temperature-resistance curves of general 4N oxygen-free copper wire (Nippon Cu) and graphene superconducting copper wire. [Figure 8] It is a temperature-resistance curve diagram of graphene. [Figure 9] It is a thermal expansion data diagram of general copper plate, oxygen-free copper plate, and graphene superconducting copper plate. [Figure 10] It is a comparison diagram of the temperature rise data of pure copper and graphene superconducting copper. [Figure 11] It is a comparison diagram of the resistance increase rate and input energy of graphene superconducting copper and general copper wire in Example 1. [Figure 12] It is a schematic diagram of a generator and a toroidal transformer employing graphene superconducting copper in Example 1. [Figure 13] It is a schematic diagram when a pulse voltage is applied to an electric motor employing graphene superconducting copper in Example 1 and each phase coil pair.

Modes for Carrying Out the Invention

[0017] This invention provides the use of graphene-supercopper in the field of high-current devices. In graphene-supercopper, the carbon atoms of graphene are distributed in the gaps between copper atoms.

[0018] In this invention, the copper atoms and the carbon atoms of graphene bond together, forming a metallic covalent bond.

[0019] In the present invention, the graphene supercopper is preferably manufactured according to the method described in Chinese Patent (CN 113073221 B).

[0020] In this invention, the thermal expansion coefficient of the graphene supercopper is <15.7 μm / (m·℃) at 200℃ or less.

[0021] In the present invention, the high-current device preferably includes an electric vehicle or an AI server.

[0022] In the present invention, the high-current device preferably includes wires for drones, semiconductor electronics, or defense and military industries.

[0023] In the present invention, it is preferable that the form of use of the graphene supercopper includes wire, target material, foil material, or powder.

[0024] In the present invention, the graphene supercopper is subjected to a vacuum melting treatment before use, and the vacuum melting process The temperature is preferably 1100 to 1500°C. The present invention does not impose any special limitations on the vacuum melting time, and can be adjusted as needed.

[0025] The technical solutions provided by the present invention will be described in detail below by combining examples, but these should not be construed as limiting the scope of protection of the present invention.

[0026] [Example 1] In this embodiment, graphene supercopper is produced according to the method described in Chinese Patent CN113073221B.

[0027] [Performance Test] 1) The graphene supercopper produced in Example 1 (with a graphene mass ratio of 700 ppm in the supercopper) was vacuum melted at 1500°C and processed into a master rod with a diameter of 8 mm. Tests were performed using a high-resolution HR TEM electron microscope, and the results are shown in Figure 1. In Figure 1, a is a diagram illustrating the formation principle of supercopper, where graphene supercopper is formed by the reaction of graphene and copper. b is an electron microscope image of graphene supercopper, where the large white dots represent copper atoms and the small white dots represent carbon atoms. From Figure 1, it was found that graphene supercopper is a metal covalent alloy material formed by the bonding of copper atoms and carbon atoms.

[0028] 2) Testing by the National Taiwan University Center for Valuable Equipment The graphene supercopper produced in Example 1 (with a graphene mass ratio of 2000 ppm in the supercopper) was vacuum melted at 1500°C and sprayed onto a powder with a particle size of 25 μm. Micro-differential scanning calorimetry analysis was performed on both the supercopper and commercially available 4N oxygen-free copper (average particle size 25 μm), and the results are shown in Figure 2 (4N oxygen-free copper) and Figure 3 (supercopper).

[0029] The DSC results in Figure 2 show that graphene-superabsorbent copper requires more energy to melt, and furthermore, graphene-superabsorbent copper has two melting points. This indicates that the microstructure of superabsorbent copper is more robust and reliable.

[0030] 3) The graphene supercopper produced in Example 1 was vacuum melted and processed to a diameter of 8 mm, and then stretched into a supercopper wire with a diameter of 2 mm. Raman spectroscopy was performed on the wire, and untreated graphene was also subjected to Raman spectroscopy. The results obtained are shown in Figures 4-5. The inset in Figure 4 is a partial enlargement. From Figures 4-5, it was found that graphene supercopper possesses D and G bonds similar to those of graphene.

[0031] 4) The graphene supercopper (with a graphene mass ratio of 700 ppm in supercopper) produced in Example 1 was vacuum melted at 1500°C and processed into an 8 mm diameter master rod, which was then stretched into a 50 μm diameter supercopper wire. IV curve and temperature resistance tests were performed on both the supercopper and commercially available Nippon 50 μm copper wire, and the results are shown in Figures 6-7.

[0032] When current passes through a copper wire, the power consumption P = I 2 R is generated. This power consumption is converted into thermal energy, which increases the temperature of the copper conductor, increases the impedance, further increases power consumption, and further increases the temperature. This vicious cycle leads to the destruction of the system, which is called thermal breakdown. From Figures 6-7, it can be seen that the graphene supercopper used in the present invention has a lower temperature coefficient than oxygen-free copper, which can improve efficiency, and as the temperature rises, the increase in resistance of graphene supercopper is lower than that of oxygen-free copper, which reduces the risk of thermal breakdown, improves efficiency, and enables power saving.

[0033] 5) Resistor Positive Temperature Coefficient (PTC): This refers to the increase in a material's resistance as its temperature rises. A larger temperature coefficient means a greater increase in resistance under the same temperature change.

[0034] Negative temperature coefficient (NTC): This refers to the decrease in a material's resistance as the temperature rises. The resistance of semiconductors and insulators decreases with increasing temperature. Graphene, semiconductors, and ceramics all have a negative temperature coefficient.

[0035] Figure 8 shows the temperature resistance of graphene, which is taken from the prior art (Supplementary Information, November 2011. High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network.) and shows that graphene has a negative temperature coefficient (NTC). On the other hand, the temperature resistance coefficient of pure copper is approximately 0.0039, and the temperature resistance coefficient of graphene-superabsorbent copper is approximately 0.0030 to 0.0033, indicating that the temperature resistance coefficient (TCR) of graphene-superabsorbent copper is smaller than that of pure copper.

[0036] 6) The graphene supercopper produced in Example 1 was vacuum melted to produce a copper ingot, which was then rolled to produce a supercopper sheet with a thickness of 0.2 mm. This supercopper sheet was subjected to a coefficient of thermal expansion (CTE) test against an oxygen-free copper sheet (4N copper sheet, thickness 0.2 mm) and a general copper sheet, and the results are shown in Figure 9 and Table 1.

[0037] [Table 1] Table 1 and Figure 9 show that the thermal expansion coefficient of graphene supercopper is 8.3% lower than that of oxygen-free copper plate at 100-150°C, and 22.8% lower at 200-250°C.

[0038] 7) Comparison of current and temperature rise: Test materials: 1. Pure copper wire, 128 strands, each strand with a diameter of 0.2 mm. 2. The graphene supercopper (with a graphene mass ratio of 700 ppm in supercopper) produced in Example 1 was vacuum melted at 1500°C, then processed into a master rod with a diameter of 8 mm, and further stretched to a wire diameter of 0.2 mm to produce 128 strands of twisted wire. The results obtained are shown in Figure 10 (comparison of input current (55A / 75A) and temperature for pure copper and supercopper wire) and Table 2.

[0039] [Table 2]

[0040] Figure 10 and Table 2 show that the temperature of the supercrystalline copper decreases by 14°C at 55A and by 31°C at 75A. Graphene supercrystalline copper allows for a larger current to pass through the same cross-sectional area, increasing by 10-20%.

[0041] 8) Actual measurements of the fast charging stand Test materials: 1. Oxygen-free copper wire, each strand with a diameter of 0.2 mm. A rapid charging cable was fabricated using a multi-strand stranded wire. 2. The 700 ppm graphene supercopper produced in Example 1 was vacuum melted to a diameter of 8 mm, and then stretched to a wire diameter of 0.2 mm to create a multi-strand rapid charging cable. Manufactured in the same stretching plant, only the conductor wire material was changed to graphene supercopper; the D+ terminal remained unchanged (the terminal material was the same). The water flow rate and fan speed were reduced by 50%, and the rapid charging cable was measured using a 600A DC electric vehicle to test the temperature difference between graphene supercopper and 4N copper.

[0042] Restrictions: The internal temperature of the wire must not exceed 125°C, and the temperature of the D+ terminal must not exceed 90°C. The results are shown in Table 3.

[0043] [Table 3]

[0044] Table 3 shows that using graphene-enhanced copper as a wire conductor significantly reduces the temperature and increases the current by approximately 20%.

[0045] Furthermore, by changing the D+ terminal material to graphene-super-copper, the fast charging time can be extended, indicating that graphene-super-copper is more suitable for the future development of 800A and 1000A fast charging.

[0046] 9) 20 cm lengths of ultra-high-strength copper wire of different diameters were taken, a variable current source was connected to both ends, and the temperature was measured using a thermocouple at the center point. The output current of the current source was adjusted in a room temperature environment of 25°C until the temperature measured by the thermocouple stabilized at 75°C. This current represents the current capacity. A tendency was observed for the current density to increase as the wire diameter decreased.

[0047] [Table 4]

[0048] Table 4 shows that the current capacity of graphene supercopper is significantly higher than that of ordinary oxygen-free copper of a similar wire diameter, and this difference becomes larger as the wire diameter decreases. Since current density = current capacity / cross-sectional area, it was found that the current density of graphene supercopper is clearly improved compared to ordinary oxygen-free copper.

[0049] 10) The resistance increase rate and input energy of graphene supercopper in Example 1 were measured and compared with those of a general copper wire. A schematic diagram of the test and the results are shown in Figure 11.

[0050] Figure 11 shows the results of applying a constant current to ordinary copper wire and ACOOL copper wire in the same test. Figure 11 is a comparison of the resistance increase rate and input energy between graphene ACOOL copper and ordinary copper wire in Example 1. It was found that when the same energy was applied, the resistance increase rate of ACOOL copper wire was slower than that of ordinary copper wire. This indicates that the resistance of ACOOL copper is much lower than that of ordinary copper.

[0051] 11) Fields of use of superpolymer copper

[0052] Because the resistance of super-high-performance copper wire increases gradually when current is input, the induced current becomes larger when used in a generator.

[0053] Figure 12 is a schematic diagram of the generator and toroidal transformer employing graphene supercopper in Example 1. As shown in Figure 12, the measured output power of the generator increased by 15-20%, and the measured output power of the toroidal transformer also increased by 15-20%.

[0054] 12) Use in electric vehicles

[0055] Figure 13 is a schematic diagram of the electric motor employing graphene supercopper and the application of pulse voltage to each phase-phase coil pair in Example 1. As shown in Figure 13, the pulse voltage of the drive motor employing supercopper coils can prevent overcharging by reducing the duty cycle and reduce energy consumption by 15-20%.

[0056] The above are merely preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A use of graphene-superpolymer copper in the field of high-current devices, characterized in that 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 atom and the carbon atom of graphene bond together, forming a metallic covalent bond.

3. The use according to claim 1, characterized in that the thermal expansion coefficient of the graphene supercopper is <15.7 μm / (m·°C) at 200°C or less.

4. The use according to claim 1, characterized in that the high-current device includes an electric vehicle or an AI server.

5. The use according to claim 1, characterized in that the high-current device includes drones, semiconductor electronics, or conductors for defense, military, and industrial applications.

6. The use according to claim 1, characterized in that the form of use of the graphene supercopper includes a wire, a target material, a foil material, or a powder.

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

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