A review on opportunities of thermionic regeneration system in hybrid electric vehicle

Abstract

A hybrid electric vehicle utilizes power from both engine and battery to drive the wheels. Hybrid electric vehicle architectures are micro, mild, full and plug in hybrids. This review covers recent optimization in technologies and systems of hybrid electric vehicle. It is evident from the literature that utilizing waste energy such as braking losses for battery charging is more effective for micro and mild hybrid electric vehicle. The increase in electrification increases the demand of alternate battery charging methods in vehicle. Therefore, the opportunity lies in recovering waste heat of engine for battery charging. This could be done by direct energy converters such as thermoelectric and thermionic converters. The paper comprehensively studies these direct energy converters on the basis of their working principle and conversion efficiencies. The results from this study show that thermionic energy conversion stands better for hybrid electric vehicles as compared with other direct energy conversion methods.