Electric Drive Train Efficiency Analysis Based on Varied Energy Storage System Usage for Plug-In Hybrid Electric Vehicle Applications

Plug-in hybrid electric vehicle (PHEV) drive trains are predominantly dependant on the energy storage system (ESS), compared to those of regular HEV. One of the major current issues in the auto-industry related to PHEVs is the type of battery system which favors the technology the most. The main aim of this paper is to investigate the effects of varying ESS types on the overall electric drive train efficiency of a PHEV. Effects of three major battery types are discussed, the lead-acid (PbA) battery, the nickel-metal hydride (Ni-MH) battery, and the nickel-cadmium (Ni-Cd) type of battery system. One of the major objectives of this paper is to find the most suitable ESS option in order to maximize the overall electric drive train efficiency of a PHEV. The resultant motor/inverter efficiencies as well as ESS charge/discharge/roundtrip efficiencies are calculated and studied, in order to compute the overall electric drive train efficiency.