Development of Fuel Cell Hybrid Vehicle by Using Ultra-Capacitors as a Secondary Power Source

Hyundai motor company has developed a fuel cell hybrid vehicle that has ultra-capacitors as a secondary power source. The simulation of fuel cell vehicles allows the user to analyze various types of fuel cell systems and hybrid configurations before implementing into a real system and to reduce the development time and cost. Before implementing fuel cell vehicles, a fuel cell vehicle simulation model, that has component modularity and forward facing characteristics, was developed. The simulation model was used in designing the fuel cell hybrid vehicle to select component sizes and a hybrid configuration. The hybridization by using ultra-capacitors provided better fuel economy and power response than the hybridization by using batteries. The main reason of highly improved fuel economy is that the ultra-capacitors have much higher charging-discharging efficiency than the batteries have, and the ultra-capacitors can also be connected to the fuel cell stack directly without a DC/DC converter.