Fuel cells as range extender or auxiliary power unit for electric vehicles

Battery electric vehicles offer zero local emission transportation in urban environments. However, their operating range is limited and becomes unreliable e.g. under cold weather conditions. This hampers in particular the use for commercial traffic. In order to overcome this obstacle an additional on-board power source delivering electricity and heat is required. The use of a fuel cell will thereby maintain most if not all of the environmental benefits expected from electro-mobility. The degree to which low emission can be achieved depends essentially on the fuel cell technology which is used. The Fraunhofer ICT is currently engaged in the development of three different Range-Extender and APU solutions. For the use as APU light duty commercial vehicles a 3 kW HT-PEMFC based system with diesel or petrol steam reformer is developed. A 5 kW HT-PEMFC based system with methanol steam reformer is developed for use as range-extender for small passenger cars for regional transportation. Finally an up to 15 kW hydrogen PEMFC system is under development as range extender for midsize passenger cars. In the contribution the different concepts will be explained and their advantages for the particular application will be discussed.