Zero emissions. Lightweight electromobile with ROHACELL® body crosses Australia almost exclusively on wind energy.

The Wind Explorer pilot vehicle is a two-seated electromobile that weighs just 200 kilograms and with a range of 400 kilometers per battery charge. The bodywork consists mainly of a carbon fiber composite with ROHACELL® structural foam from Essen, Germany-based Evonik Industries. Its lithium-ion batteries, based on yet another Evonik technology, are charged by a mobile wind turbine or—in exceptional cases—in the conventional way from the power grid.

German extreme sports enthusiasts Dirk Gion and Stefan Simmerer made international headlines with their pioneering 17-day journey across Australia in late January of 2011 in this electric vehicle powered by wind and lithium-ion batteries. The pilots could recharge flat batteries using either a mobile wind turbine or from the grid in the usual way, depending on the wind situation. The wind turbine and a 6-meter-high telescopic bamboo mast are set up within 30 minutes. The Wind Explorer was propelled partly by parasail-style kites in addition to wind power, achieving in this way a maximum speed of about 80 kilometers per hour on the approximately 4,900-kilometer stretch from Albany on the Indian Ocean to Sydney. Only in exceptional cases did the pilots resort to electricity from conventional sources.

Lighter and further

When they built the electromobile, the duo opted for a tried-and-proven lightweight construction material: a sandwich structure of carbon-fiber fabric and a structural core of Evonik's ROHACELL® polymethacrylimide (PMI) rigid foam. This fiber plastic composite has been used with great success for many years in aircraft, helicopters, trains, and ships, and is also rapidly gaining ground in automotive construction: ROHACELL® structures allow weight savings of 60 percent or more over conventional steel parts. “And every gram of weight saved reduces CO2 emissions in conventional fuel vehicles and increases the range of the electric vehicles of the future,” says Stefan Plass, who is responsible for ROHACELL® business at Evonik, describing the driving force behind developments for the automotive industry.

The high rigidity of the foam also improves the inherent rigidity of the components. And thanks to the high thermal resistance of the material, three-dimensional ROHACELL® cores are easily produced by thermoforming with short cycle times.

ROHACELL® is CFC-free and, in compliance with Directive 2000/53/EC on end-of-life vehicles, heavy-metal-free, and is listed in the IMDS. Tests at KTH Aeronautical and Vehicle Engineering in Stockholm and the University of Cranfield, and by Lotus Engineering, testify to its excellent crash properties.