Micro-mixed mode (Kai / stop system), are generally used 12V battery (some with 14V). Relative to the traditional car, the main change is the application of AC motor. The introduction of the exchange system to bring the biggest problem is the electromagnetic interference. The former low-voltage systems are DC systems, electromagnetic interference problems are not significant, and now have a large current AC applications, electromagnetic shielding (anti-electromagnetic interference) has become a very important issue.
In the mixed mode of new energy vehicles, the biggest difference is the introduction of high voltage battery pack, the voltage reaches 120V, or even higher to 144V, and the current supplied to the AC motor is usually between 100 ~ 150A, which gives the entire high voltage electrical circuit To challenge. In addition to the same to solve the anti-interference problem of AC motor, but also need to solve the high-voltage wiring harness to bring security risks. This is because the battery pack is usually in the rear of the car, while the AC motor is in the front of the car, which requires high pressure system through the entire car. The traditional low-voltage wiring harness can be passed from the inside of the car, and if the high-voltage wire harness passes through the car, it brings a considerable safety hazard. Therefore, the high-voltage wiring harness needs to pass from the outside of the vehicle, which in turn poses a new problem for the mechanical protection of the high-voltage electrical system.
The hybrid electric vehicle is similar to the technical type of the plug-in hybrid vehicle. The battery voltage is between 288 and 360V. The power of the motor is usually increased from more than 10 kW to more than 25 kW and up to 40 kW to 60 kW. In this high-voltage high-power, the current up to 250A or even 300A. Usually this level of current, only in industrial occasions, high-power power equipment will be applied, and now to be used in the car, the car's space and load put forward new challenges.
High voltage electrical systems involve components including high voltage wiring harnesses, connectors and power distribution systems. The plug-in hybrids and all-electric vehicles also involve charging systems, which are areas of high-voltage electrical systems. The challenge for high-voltage electrical systems for new energy vehicles is to solve them through these components.
The first is the harness. The upgrading of the wiring harness means that the wire harness must be very thick, which makes the wiring direction and electromagnetic interference and shielding become very important. Therefore, harness mechanical protection is very important, because the electric vehicle's high-voltage wire harness is usually arranged outside the car. So thick high-voltage wiring harness to be arranged in the smallest space, but also take into account its protection and anti-interference, which requires a new solution. Another factor to consider is the high vibration environment where these harnesses are located. The harnesses are worn during vibration, so it is a new challenge to optimize the layout and anti-fatigue design for wire harness quality.
In response to these challenges, there are two methods, one is now widely used in domestic technology, that is, the wiring harness in the plastic trunking. Which is characterized by low cost, but the disadvantage is that it requires a relatively large space, the harness can not play a very good protection. Another technology is Japan and the United States of America car company commonly used bending technology. That is, with a lightweight metal tube for protection, the harness from the metal tube into the wear, and then put the metal tube with a harness together with the same shape of the shape of the chassis layout. The harness is usually a flexible part, and with this technology, the high-voltage wire harness becomes a rigid part, just like a mechanical part. This bend technology is easy to install, mechanical protection performance is better than plastic trunking.