Impact of thermal-electric networks on the usability of EVs based on a study with a C-segment car

Abstract

One of the major concerns of contemporary Fully Electric Vehicles (FEV) is the high dependency of the maximum range on ambient temperature conditions. In some cases the range of an EV can drop by more than 50%. One of the main reasons for this behaviour is the energy demand required by the thermal conditioning of the passenger compartment. Within this paper a comprehensive approach will be presented to reuse the waste heat energy of the powertrain components combined with a thermal storage for conditioning the car’s cabin. To evaluate the influence of the ambient temperature on the vehicle range, an electro-thermal simulation of a C-segment car, including the HVAC (Heating, Ventilation and Air Conditioning) and the cooling system was performed. The following components/systems were considered: battery, thermal energy storage, thermal insulation as well as heat pump and thermal preconditioning due to an inductive charger. It will be shown that, despite a low amount of waste heat from the high voltage components, the combination of the heat pump with the thermal energy storage (using advanced control strategies) leads to a remarkable range improvement. This research is based on the integration of new electro-thermal system components including novel control algorithms into the thermal system layout. In this article modern control approaches for heat-pump subsystem as well as overall control strategies for complete electro-thermal networks will be discussed. Model-based development has been proven to be an efficient way of control algorithms and software design, including advanced control techniques like MPC and virtual sensors. To validate the simulation results the system will be integrated in a demonstrator car (Mercedes Benz B-Class).