Effect of extreme temperatures on battery charging and performance of electric vehicles

Extreme temperatures pose several limitations to electric vehicle (EV) performance and charging. To investigate these effects, we combine a hybrid artificial neural network-empirical Li-ion battery model with a lumped capacitance EV thermal model to study how temperature will affect the performance of an EV fleet. We find that at -10 degrees C, the self-weighted mean battery charging power (SWMCP) decreases by 15% compared to standard 20 degrees C temperature. Active battery thermal management (BTM) during parking can improve SWMCP for individual vehicles, especially if vehicles are charged both at home and at workplace; the median SWMCP is increased by over 30%. Efficiency (km/kWh) of the vehicle fleet is maximized when ambient temperature is close to 20 degrees C. At low (-10 degrees C) and high (+40 degrees C) ambient temperatures, cabin preconditioning and BTM during parking can improve the median efficiency by 8% and 9%, respectively. At 10 degrees C, preconditioning and BTM during parking can also improve the fleet SOC by 3-6%-units, but this also introduces a base load of around 140 W per vehicle. Finally, we observe that the utility of the fleet can be increased by 5%-units by adding 3.6 kW chargers to workplaces, but further improved charging infrastructure would bring little additional benefit. (C) 2016 Elsevier B.V. All rights reserved.