Energy storage systems considerations for grid-charged hybrid electric vehicles

This paper discusses battery power and energy requirements for grid-charged parallel hybrid electric vehicles (HEVs) with different operating strategies. First, it considers the traditional all-electric-range-based operating concept and shows that this strategy can require a larger, more expensive battery due to the simultaneous requirement for high energy and power. It then proposes an alternative "electric-assist" operating concept for grid-charged HEVs to enable the use of a smaller, less costly battery. However, this strategy is expected to reduce the vehicle efficiency during both charge-depleting and-sustaining operation. The paper concludes by identifying several key questions for future research.