Heat load estimation and thermodynamic analysis of the thermal management of an electric car

Abstract

Thermal management of electric vehicles is a key step in their wide spread and safe usage. This work considers an electric car as a combination of three entities which contribute to the thermal load viz. the battery, motor and passenger cabin. A refrigerant based cooling system is proposed and is applied to a mid-size electric car (∼60 kW) to obtain the heat load, sizing of the components and the performance analysis based on the 1st and 2nd laws of thermodynamics. At nominal operating conditions, the battery offers a heat load of 3.3 kW, motor of 3.25 kW and cabin of 4.53 kW. However, at adverse operating conditions, the battery offers a heat load of 4 kW, motor of 3 kW and cabin of 3 kW. The proposed cooling system successfully evacuates the heat and manages the temperature of the electric vehicle. The exergy destruction at different ambient conditions also is studied and is found to increase at higher ambient temperatures. Compressor is found to be carrying out the maximum exergy destruction.