The affect of battery pack technology and size choices on hybrid electric vehicle performance and fuel economy

This paper is a comparative study of three hybrid-electric vehicles, three powertrains per vehicle and three battery technologies to determine the optimum configuration required to maximize fuel economy and vehicle performance. The qualitative analysis discusses various design decisions and sets forth the advantages and disadvantages associated with different hybrid configurations. Numerous computer modeling simulations are performed to investigate the various aspects of the hybrid vehicle design. The simulations generated vehicle performance results including urban and highway fuel economy and acceleration times. Results indicate that nickel metal hydride and lithium ion batteries provide optimum performance. Lithium ion technology is slightly better in the small battery pack charge sustaining hybrid (PO) options and for the SUV. Nickel metal hydride is the best battery choice of charge depleting hybrids with 20 and 60 miles of all electric range (P20, P60) for small and midsize cars. The general trend seen is that vehicles with larger battery packs perform better and are more efficient. In short, the parallel hybrid-electric is a true interim vehicle, on the road to true zero emissions, that appears to be capable of satisfying the Partnership for a New Generation of Vehicles consortium (PNGV) and the California Air Resources Board's (CARB) LEV II requirements.