Performance analysis of an integrated battery electric vehicle thermal management

Abstract

Fast introducing battery electric vehicles to the market leads to the accumulation of errors and recalls of the vehicle. It can be avoided by simulating battery electric vehicles (BEV) in an integrated manner. A drivetrain model is developed integrated with cabin, battery, and power electronics models. Key system-level outputs like vehicle energy consumption, system COP, and total auxiliary power are obtained, and component-level outputs include internal battery temperature, power electronics temperature, and cabin temperatures. The integrated model is validated both at the component level and system level. Simple energy-conscious actions are identified, and corresponding energy savings are quantified over the lifetime of a battery-electric vehicle. Simple energy-conscious actions can save 1336 to 4297 kWh of energy throughout the vehicle's lifetime. When the ambient temperature is doubled from 25 to 50 °C, total auxiliary power increases around six times, energy consumption increases by 35 % per kilometer, and mean COP drops by 39 % for the US06 driving cycle. This model is applied to various Indian cities to compare energy consumption. Drivetrain model parameters like vehicle mass, motor and transmission efficiency, and road gradability are varied to estimate their effect on battery electric vehicle energy consumption. Considerable effects of solar load, cabin's initial temperature, and cabin's target temperature are observed. Two different cooling loops for the battery thermal management are simulated to observe terminal voltage and internal cell temperature response. A temperature drop of 5 °C in internal cell temperature is observed when cabin exit air is blown on the battery radiator instead of ambient air. The effect of road gradability and coolant flow rate on power electronics transistor and diode temperature are also quantified.