A virtual test rig for performance and efficiency assessment of heat pump thermal management system for battery electric vehicles

In a Battery Electric Vehicle (BEV), the optimization of its thermal state plays a crucial role in the achievement of relevant vehicle targets such as range, passenger comfort, and recharging times, as well as varying external ambient conditions. Therefore, selecting the most proper solution between the many possible architectures to manage the different thermal loads of a BEV needs the support of a robust simulation platform. In such a framework, a comprehensive numerical twin of an electric city car was developed in the GT-Suite environment and validated against experimental data. Through that, the promising performance of a Heat Pump (HP) based thermal layout has been demonstrated, against a standard Air Conditioning system integrated with a PTC heater, on a wide range of external ambient temperatures (reaching up to +20% driving range improvement in cold conditions). The present layout proposed a sustainable alternative to the most common R134a as working fluid (i.e., propane) and the integration of multiple heat sources. In addition, different battery preconditioning strategies have been tested, tailored to the selected real-world mission profiles, obtaining a remarkable gain in terms of driving range for the HP system in cold conditions (up to 6% at -10 C and 4% at -20 C).