Case Study of Dual ESS for a Full-electric Bus Combining a Li-Ion Battery with an Environmentally-friendly DLCAP^TM

Green Houses Gas (GHG) emission reduction and fossil fuel economy are becoming important global issues. In Chinese cities, new commercial vehicles using diesel engines are not allow--new buses must be zero-emission electric vehicles (E-bus). A fully-loaded E-bus with a mass of 15 to 19 tons requires batteries offering both high energy for long driving range and high-power for acceptable vehicle acceleration. Advantages may be gained by using a dual energy storage system, part comprised of batteries with high energy to provide long range and part comprised of electrochemical capacitors with high power to provide acceleration and efficient regenerative energy capture. This paper examines performance advantages possible with such dual energy storage systems in pure electric E-bus vehicles. Two different control strategies were investigated. Results show that a 44% range increase is possible over an all-battery system.