ABSTRACT
In this chapter, hybrid energy storage systems (ESS) are presented for the decoupled power and energy components of the plug-in electric vehicles (PEVs*). A stand-alone battery system with an energy capacity sized to propel the vehicle some distance at a moderate speed on a single charge in an all-electric mode may not be sufcient to satisfy peak demand periods and transient load variations in PEVs. In such a case, the battery would need to be oversized to supply the extra power needed to overcome these limitations, thus increasing the weight, volume, and cost as well as the number and depth of charge/discharge cycles. All these factors lead to concern over battery lifetime, which is one of the strongest barriers currently preventing rapid commercialization of PEVs. Alternatively, an ultra-capacitor (UC) bank can supply or recapture large bursts of power at high C-rates.
