Range Extender Technology for Electric Vehicles

The demand for improved fuel economy and the request for Zero Emission within cities require complex powertrains with an increasing level of electrification already in a short-termed timeframe until 2025. According to general expectations the demand for Hybrid powertrains will increase significantly within a broad range of implementation through all vehicle classes as well as on battery electric vehicles (BEV) mainly for use in urban areas. For a broad acceptance of battery electric vehicles, the trade-off between all electric range and battery cost respectively weight represents the most important challenge. The all electric range obtained under real world conditions most often deviates significantly from the nominal value which is measured under idealized conditions. Under extreme conditions - slow traffic and demanding requirements for cabin heating or cooling - the electrical range might become less a question of spatial distance but even more of total operation time. As long as no sufficient charging infrastructure is available, measures for BEV have to applied to avoid "Range Anxiety" of the user. This may be additional battery capacity, which is increasing cost and weight proportionally to requested range. Alternatively, a so-called Range Extender (RE) with internal combustion engine (ICE) may be integrated, of course also increasing cost and weight, but independent from requested driving range. In the last years AVL has developed several solutions for electrification of the powertrain as well as Range Extenders for battery electric vehicles. The different solutions cover REXs with Rotary engine, 2- and single cylinder engines derived from motorcycle applications. In the present paper the different solutions are described and the priorities for application as well as practical use are explained.