Plug-in hybrid electric vehicle charging: Current issues and future challenges

There has been an increasing attraction towards plug-in hybrid electric vehicles (PHEVs) within the auto industry. However, high battery prices and short life spans have led to growing interest in development of advanced charging techniques and algorithms. In this paper, the characteristics of batteries used in PHEVs, which include Pb-acid, Ni-Cd, Ni-MH, Li-ion, and Li-polymer are reviewed, and different charging methods such as constant voltage, constant current, pulsed charging and burp charging are investigated. Termination methods such as time, voltage, voltage drop (dv/dt), current, and temperature are also discussed. Suitable charging algorithms for these battery types will be reviewed and evaluated. Battery charging issues such as cell equalization, state of charge estimation and thermal management will be discussed. Finally, future research trends of charging of PHEVs are described.