Energy Efficiency Analysis of Electric Vehicle System Components

There are several figures used to promote the energy efficiency of battery electric vehicles (BEVs). A critical analysis of the energy consumption of BEV systems is presented here. A typical approach to estimate the efficiency of BEVs is to use fixed values for each component. Often the best possible value is taken in use. In practice, the efficiencies vary as a function of the operation point of the device and ambient conditions where the EV is used. It is also important to remember that propulsion is just part of the energy consumption in a modern EV and other consumers like air conditioning may use a high share of energy. The range of efficiency of each stage of an EV system is presented and the influential factors are discussed.