Universal Electric Vehicle Thermal Management System

As the demand for Electric Vehicles (EVs) is increasing to limit global warming, observation shows that the significant application of EV is in cold and mild climate regions. Heat pump and CO2 system are two major Thermal Management Systems (TMS) used in these EVs. These TMS are constrained to cold climate applications securing better COP for heating function but sacrificing cooling COP when the same TMS applied to hot climate regions. This study presents a new Electric Vehicle Thermal Management System (EVTMS) limited to active liquid battery cooling for the application of Electric Vehicles in hot climate regions. The proposed system has integrated Battery Thermal Management System and Cabin HVAC using a shared electric compressor. This integrated solution also utilizes waste heat recovery to contribute for better system COP when compared to conventional TMS used for EV's. The decrease in the number of pipes and switching valves due to integrated solution also results in low refrigerant pressure drop preventing penalty on compressor duty. Battery cells target temperature of 27°C and, temperature delta of 4°C across battery cells is also considered as a prime motive during this study. Different strategies to control battery cells target temperature; the cabin HVAC system is studied. System simulation for typical thermal load in an EV is the first objective. The benefits of the proposed system are validated using an experimental test at a typical load condition. COP comparison for an existing system with proposed EVTMS proves the proposed system to be 50% energy efficient under typical thermal load from battery and cabin.