What is Hybrid Electric Vehicle

The number of disasters caused by global warming has increased in recent years, making it important to accelerate the studies on alternative and clean energy conversion systems to decrease these detrimental effects. Conventional transportation systems mainly based on fossil fuels seem to be the most critical issue for the environment. Electric vehicles are promising clean candidates that can be used for transportation. Electric vehicle technology can be classified into battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell electric vehicles (FCEVs). In recent years, due to the development in nanotechnology and material science engineering, newly designed battery and fuel cell-based technologies draw attention. This chapter aims to give brief information about the electric vehicle types, a comparison of the existing systems, hydrogen fuel cell electric vehicles and drawbacks of these systems, and the current status of the hydrogen economy.