Requirements of electric vehicle wiring harness design

In order to reduce the impact of motor vehicles on the environment, meet the requirements of fuel economy and carbon dioxide emissions related legislation. The introduction of hybrid and electric vehicles is a good choice for automakers. In the next few years, the global demand for such alternative energy vehicles will increase day by day.

However, while electric vehicles bring environmental protection, they also have their own imperfect factors. How to shield the electromagnetic wave generated during the high-voltage operation of electric vehicles, as well as the interference of electric vehicle wiring harnesses, and the sealing performance of wiring harnesses and connectors. Therefore, when designing and developing hybrid and electric vehicles, these problems need to be solved, otherwise safety risks will arise.

Electromagnetic wave shielding, solving the interference of wiring harness

Hybrid vehicles are attracting attention because of their fuel economy, but at the same time it also poses a problem for automakers, that is, electromagnetic interference (EMI). It is always necessary to optimize electromagnetic interference with electronic module and wiring harness design, even in 12V systems. This harmful noise can interfere with radio reception and other vehicle signals such as AM/FM radio frequencies, mobile phone usage, and Bluetooth capabilities. Hybrid vehicles must rely on high-current and high-voltage inverters to drive. However, high-power inverters will generate electromagnetic interference with a frequency range of 100.0kHz to 200.0MHz. The high-power AC and DC conversion of these inverters makes the electromagnetic interference problem of hybrid vehicles more serious.

In contrast, when converting alternating current to direct current to charge the battery pack, the weight of the electronic device is lighter, so it has better performance than the transformer. In fact, electronic equipment is currently the only viable technology that is suitable for AC and DC conversion and uses battery packs to drive vehicles. However, these electronic devices will generate more electromagnetic interference, because the high-voltage wiring harness will act as an electromagnetic interference antenna to transmit electromagnetic interference to the entire car body.

In traditional vehicles, the most effective way to suppress electromagnetic interference noise is often to use capacitors, inductors, diodes and other components. But now, shielded electronic modules and wiring harnesses have become a more economical solution for hybrid vehicles because they are smaller and lighter than traditional suppression components.

Solution to the safety problem of the use of electric vehicle wiring harness

In order to ensure the safety of drivers and maintenance technicians in a high-voltage environment, we must consider a series of complex factors in the electrical system to ensure reliability and optimality. The connection system is a key component of high-voltage electrical wiring harnesses, especially the design of high-power wiring harnesses. From a safety perspective, two aspects should be paid attention to in the design of high-voltage connection systems, namely, the high-voltage interlock circuit (HVIL) and the environmental sealing of the connector (to avoid short circuits between high-voltage terminals when the vehicle is used).

Since unsealed lines can lead to failure modes such as short circuits, the sealing of high-voltage lines is critical. As everyone knows, water and electricity are incompatible. The use of wire ring seals and connector peripheral seals can make the connector truly sealed, ensuring that moisture cannot enter, and will not cause overheating or sparks. Compared with the traditional 12V system, the high voltage system needs a stronger seal, because the higher the voltage, the greater the chance of flashover.