The Application of Copper in New Energy Vehicle Wiring Harness

The amount of copper used in the low-voltage Wiring Harness system of each gasoline vehicle and electric vehicle is 18kg and 23kg, respectively. With the daily improvement of car driving intelligence and comfort, cars provide more and more electronic functions, such as ADAS, infotainment systems, etc., requiring more and more complex low-voltage wiring harness systems. According to research data from IDTechEX and the International Copper Association in 2017, the low-voltage wiring harness system of each fuel vehicle uses 18kg of copper, accounting for the majority of the copper used in fuel vehicles. With the deepening of the network connection and intelligence of electric vehicles, the amount of copper used in the low-voltage wiring harness system of each electric vehicle (including pure electric vehicles, hybrid vehicles, and plug-in hybrid vehicles) reaches 23kg.
The low-voltage wiring harness systems of automobiles mostly use oxygen-free copper wires as conductors and copper alloy strips as connectors. The low-voltage wires in the low-voltage wiring harness are copper multi-filament flexible wires, and the conductors are mostly oxygen-free copper wires, with a copper content of more than 99.99%, which is not easy to be embrittled by oxygen; the connectors are mainly T2, C10500 red copper alloy strips. In the past year, the average price of 3mm oxygen-free copper wire was 71,500 yuan/ton, and the average price of T2 copper rod was 73,000 yuan/ton.
The value of copper used in the low-voltage wiring harness system of each fuel gas is 1291 yuan, and each electric vehicle is 1650 yuan. Assuming that in the high-voltage wiring harness system of each vehicle, 85% of the weight is copper wires and 15% of the weight is connectors. According to estimates, the value of copper used in each fuel-gas low-voltage wiring harness system is 1291 yuan, and the low-voltage wiring harness of each electric vehicle is worth 1291 yuan. The value of copper used in the system is 1650 yuan.
In addition to the traditional low-voltage wiring harness, the new energy vehicle uses the high-voltage battery pack as the power source, and the new high-voltage wiring harness is the transmission carrier. Automobile wiring harness is the main carrier to control the functions of automobile electrical and electronic components. It is the blood vessels and nerves of automobiles, providing power, transmission and feedback signals for various electronic components. According to the withstand voltage of automobile wiring harnesses, it can be divided into low-voltage cables and high-voltage cables. Traditional fuel vehicles mainly use low-voltage cables, while Electric Vehicle Wiring Harnesses have new high-voltage cables with a carrying voltage of about 600V. For new energy vehicles, especially pure electric vehicles, the power source is provided by high-voltage battery packs, and the transmission carrier is high-voltage wiring harnesses, which are connected to high-power equipment such as charging ports, high-voltage battery packs, inverters, motors, and on-board chargers. The high-voltage Cable Assembly mainly includes: high-voltage connectors, high-voltage cables, grounding terminals and cable ties, outsourcing materials, tapes, heat-shrinkable sleeves, rubber sleeves, mounting brackets and other auxiliary materials.
It is expected that the high-voltage system of electric vehicles will still be dominated by copper wires in the future. Under the trend of "lightweight" automobiles, some parts of automobiles, such as radiators, are gradually replaced by aluminum materials, which are both lightweight and economical. The development trend of automotive wiring harnesses is mainly towards lightweight, high-voltage bearing capacity, large capacity, and high efficiency. The application of aluminum wires is conducive to the lightweight of wire harnesses. In the past ten years, aluminum wires have been widely used in traditional vehicles, but there are still few cases of successful application of aluminum wires in high-voltage systems of electric vehicles. The core problem lies in the electrical performance. The conductivity of aluminum is only 60% of that of copper. The cross-sectional area of the aluminum wire needs to be increased to pass the continuous current of the same size. Although aluminum wire can reduce weight by 45% and save about half the cost, aluminum wire brings a series of wiring problems, such as taking up more space and increasing the turning radius due to the thicker wire bundle. In addition, the tensile strength and expansion coefficient of aluminum are not as good as those of copper, and aluminum oxide film is easily formed on the surface of aluminum wire, which plays a certain insulating role and affects the resistance of the contact part. It is expected that the high-voltage system of electric vehicles will still be dominated by copper wires in the future.
Electric vehicle high-voltage wiring harnesses include connectors, cables, etc., and require high electrical conductivity. The high-voltage wiring harness mainly includes: high-voltage connectors, high-voltage cables, grounding terminals and cable ties, outsourcing materials, tapes, heat-shrinkable sleeves, rubber sleeves, mounting brackets and other auxiliary materials. In the high-voltage wiring harness system, the weight of the cable is generally about 75%, and the cost is about 35%; the weight of the Connector is generally about 15%, and the cost is about 55%. Electric vehicles will mainly use electric energy, and materials with superior electrical conductivity are inseparable from the loading, control and application of electric energy. The Wire Harness conductor material is generally annealed pure copper, and some copper alloys are also used according to the requirements of different positions of the car.