I. Introduction
The age of electric vehicles (EVs) has arrived. With the increasing need for reduction in emission for slowing down global warming, EVs have attracted more and more attention from various levels of governments across the globe as well as interest from consumers. According to California New Car Dealers Association, California battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) new registrations increased from 3.6% of all vehicles to 8% in 2020. By 2030, it is estimated that EV sales share will reach 57% in California. The same trend is observed globally. The International Energy Agency (IEA) estimates that the number of EVs will reach about 130 million by 2021, a sharp increase from 5.1 million in 2018.