Review of electrical energy storage system for vehicular applications

Recently, automotive original equipment manufacturers have focused their efforts on developing greener propulsion solutions in order to meet the societal demand and ecological need for clean transportation, so the development of new energy vehicle (NEV) has become a consensus among governments and automotive enterprises. Efficient electrical energy storage system (EESS) appears to be very promising for meeting the rapidly increased requirements of vehicular applications. It is necessary to understand performances of electrical energy storage technologies. Therefore, this paper reviews the various electrical energy storage technologies and their latest applications in vehicle, such as battery energy storage (BES), superconducting magnetic energy storage (SMES), flywheel energy storage (FES), ultra-capacitor (UC) energy storage (UCES) and hybrid energy storage (HES). The research priorities and difficulties of each electrical energy storage technology are also presented and compared. Afterwards, the key technologies of EESS design for vehicles are presented. In addition, several conventional EESSs for vehicle applications are also analyzed; the comparison on advantages and disadvantages of various conventional EESSs is highlighted. From the rigorous review, it is observed that almost all current conventional EESSs for vehicles cannot meet a high-efficiency of power flow over the full operation range; optimization of EESS and improved control strategies will become an important research topic. Finally, this paper especially focuses on a type of linear engine, a brand new automotive propulsion system used for NEV; the guiding principle of EESS design for the new type of linear engine is proposed, an overview of a novel hybrid EESS based on hybrid power source and series-parallel switchover of UC with high efficiency under wide power flow range for the type of linear engine is presented, and advanced features of the novel hybrid EESS are highlighted.