Battery electric vehicles (BEVs) with in-wheel motors (IWMs) are a rapidly
emerging technology. BEVs lie in a wide power interval and are of different
types. This article considers BEVs lying in the power interval of [0.25-360] kW
and groups them into five classes. The energy efficiency of a BEV is a
determinant of its operational cost and environmental impact. A graph of energy
efficiency versus power is important while investing in new BEV technologies. In
constructing this graph over the said power interval for single motor drive
(SMD) BEVs, the existing literature on energy efficiency provides some data for
two of the five classes, while for IWM BEVs, the literature provides some data
for just one value of power. To construct these graphs for both SMD and IWM
BEVs, this article, as its primary contribution, performs a comprehensive study
of each class of BEV to gather realistic data for each stage involved in the
calculation of their energy efficiencies. It concludes that the tank-to-wheel
energy efficiency of an IWM BEV may be up to 18% higher than that of an SMD BEV
of the same power. To see how efficient the BEVs are with respect to internal
combustion engine (ICE) vehicles, this article, as a secondary contribution,
concludes that the well-to-wheels energy efficiencies of IWM BEVs, SMD BEVs, and
ICE vehicles, each of around 80 kW, are about 33%, 30%, and 18%, respectively
for natural gas pathway.
