Analysis of the energy storage battery and fuel tank of a commercial electric vehicle with range extender during charge sustaining operation

Abstract

AbstractThe energy storage of a commercial plug‐in battery‐electric vehicle (BEV) with an internal combustion engine (ICE) range extender is here analyzed covering Urban Dynamometer Driving Schedule, Hwy and US06 cycles during Charge Sustaining Operation. Instantaneous voltage, current and state‐of‐charge of the battery, vehicle speed, ICE speed, and fuel flow rate are obtained from chassis dynamometer measurements. A simple model for inertia, aerodynamics, and rolling forces for the vehicle, provides efficiencies of energy transfers/conversions through the different components, ICE, generator, discharge limiter, battery, traction motor/generator, and driveline. The results provide a benchmark of energy efficiency of current plug‐in BEV with range extender ICE. It is concluded that the energy efficiency may be dramatically improved if the low‐tech engine switched on/off when the battery is fully depleted, is replaced by a smaller high‐efficiency engine continuously operated over a fixed point. This way, a small battery can replace a large battery, with benefit to the economy and the environment, and better sustainability, for reduced construction costs and better economy of a lighter vehicle. Furthermore, the electricity production on demand may occur on board at a better fuel conversion efficiency than centralized produced distributed electricity from mostly fossil fuel sources with no need for infrastructure.