Power battery, as one of the core of new energy vehicles, directly or indirectly provides energy for the vehicle; the drive motor uses the power provided by the power battery to drive the car; the electronic control system mainly manages the power output of the drive motor. What connects these devices to realize their respective functions is the various types of wiring harnesses installed in new energy vehicles. Compared with the wiring harness in traditional cars, the wiring harness of new energy vehicles not only contains the ordinary wiring harnesses for transmitting electrical signals and low voltage devices to run the required power, but also the high-voltage wiring harness is an essential and important component. The high-voltage wiring harness in new energy vehicles bears the important mission of safely and reliably transmitting the electrical energy needed to drive the vehicle, and plays a key and important role in the safety, reliability and stability of new energy vehicles.
At this stage, automotive high-voltage wiring harnesses mainly use copper as the conductor, including bare round copper wire and tinned soft round copper wire stranded. Copper material has excellent electrical conductivity (under 20 ℃ environment, the resistance of copper is 0.0185 Ωmm2/m, and the resistance of aluminum is 0.0294 Ωmm2/m). In the case of high current, its working temperature rise is lower, on the one hand, it can reduce the heat loss during transmission, on the other hand, the excellent thermal conductivity of copper material also ensures that the working temperature of the high-voltage wiring harness is stabilized in the safe range. At the same time, due to excellent electrical conductivity, under the same load, the cross-sectional area of the copper wire can be smaller, which can effectively help the flexible arrangement of high-voltage wiring harnesses, including smaller turning radius (high-voltage wiring harnesses generally need to be more than the diameter of the wiring harness of more than 5 to 6 times the diameter of the wiring harness); In addition, the finer wiring harnesses can reduce the bending stress, installation of wiring harnesses, connectors insertion and removal of force is smaller, to help reduce the difficulty of installation and maintenance to Improve the stability and reliability of the assembly; and, smaller cross-sectional area can help high-voltage wiring harnesses are flexibly arranged in the grooves and corners of the metal body, or close to the metal body layout to effectively reduce electromagnetic interference.
☆ In addition to good electrical conductivity, copper as a high-voltage wiring harness conductor material is another advantage of better tensile strength and bending properties. Copper metal has good mechanical properties, tensile strength of 200-240 MN/M2, elongation up to 50%, its good plasticity makes it easy to process, has a high plastic deformation capacity, can be calendered, extruded and stretched and other pressure processing methods to make a variety of shapes and sizes of the products, and the use of copper as a conductor of high-voltage wiring harness in the use of the process can withstand the process of the vehicle driving vibration and friction, with high Copper as a conductor can withstand the vibration and friction that occurs during the vehicle’s traveling process during the use of the high-voltage wiring harness, which has higher reliability and longer service life.
☆ Copper material also has good chemical stability, good corrosion resistance, and easy to weld. Vehicle operating environment is complex and harsh, high-voltage wire harnesses and terminal connectors will inevitably work in the humidity, salt spray and other corrosive environment. According to the traditional automotive wiring harness experience, in the humid, high temperature and vibration environment, such as friction and collision with other parts, easy to insulator wear, loose joints, wire corrosion and other phenomena, which leads to disconnection or short-circuit and other failures. Since high-voltage wiring harnesses carry higher voltages, higher currents, and have greater stress on terminals and connectors, there are higher safety requirements that require conductor materials with better chemical stability. High-quality copper materials can both ensure that the terminals and connectors to maintain good contact for a long time, to avoid the occurrence of galvanic corrosion, but also to slow down the insulation layer aging or damaged, the harness conductor by corrosion. The field is also other materials as a high-voltage wire harness conductor needs to be comprehensive research to verify one of the main difficulties.
