Electric compressor integration noise influence in Battery Electric Vehicles

Within the automotive industry’s shift to Battery Electric Vehicles, in order to meet the global zero emission target, thermal management systems are key aspects to address. For instance, vehicle cooling requirements are reinforced to take into account the cabin comfort as well as battery management performances. Consequently to the increased cooling requirements, the critical component that is the Electric Drive Compressor, must operate at higher speeds and refrigerant pressures to achieve these targets. This trend results in increased noise levels which might occur inside the car cabin and outside. In this paper, noise investigations were performed on different Battery Electric Vehicles to assess the behavior of the electric compressor within a temperature controlled environment. Then, the electric compressors alone were investigated on specific test benches with compressor load units. The vehicle level assessment highlighted significant noise differences between vehicles. Further investigation revealed specifics in the design intent regarding the placement of the electric compressor in each vehicle. Removing the components surrounding the electric compressors confirmed the integration impact on the noise levels in those vehicles. Furthermore, additional investigations were performed at compressor level using multiple encapsulation designs. These configurations were also tested in vehicles to assess the correlation between improvements at component and in vehicle. These findings point out that the electric compressor integration to an optimized position is critical to reducing the noise levels in Battery Electric Vehicles. The encapsulation results provide an overview of the potential solutions and leverages to improve the noise at component level and at vehicles within the current market challenges.