Daimler demos innovative hydrogen-powered research vehicle

September 16, 2011 // By Christoph Hammerschmidt
Amidst ongoing discussions over the shortfalls and challenges of battery electric vehicle concepts, at the Frankfurt Motor Show Daimler presented a research car driven by hydrogen fuel cells. The vehicle boasts a large number of innovative features including its electronics.

The F125 is powered by the same near-production fuel cell stack that was used in the fleet of Daimler B-class passenger cars that circled the world recently. The hydrogen to feed this stack is stored in a tank with a capacity of about 7.5 kg of hydrogen. The tank design is rather innovative: Instead of the cylindrical high-pressure (700 bar) tanks typically used for this purpose, the vehicle's tank stores the liquid hydrogen in a porous, spongy metallic structure. With its working pressure of only about 30 bar, it was possible to integrate the tank into the floor assembly. This technology however, still is an object of basic research, Daimler admitted. 

In any case, the electric power generated by the fuel cell stack is stored in a lithium-sulphur battery - another innovation in this vehicle. With its capacity of 10 kWh, it is lighter than the lithium-ion batteries used in today's electric vehicles and Daimler hopes that by the time of its commercialization it will be able to offer a higher specific energy density of 350 Wh per kg. This, in turn, allows considerably higher recuperation rates in connection with the electric drive. The car is driven by four electric motors near the wheels. Their continuous output power of 170 kW (231 horsepowers) gives the car a top speed of 220 km/h. Nevertheless, the fuel consumption is only 0.79 kg of hydrogen per 100 km - the equivalent of 2.7 liters of Diesel fuel.

One filling of the hydrogen tank gives the vehicle a driving range of about 1000 km. In the case that the tanks are empty, it also can drive for some 50 km purely on battery. If necessary, the battery can be charged inductively.

The telematics and infotainment concept is as futuristic as the powertrain. Of course, the vehicle is "always on" - it has its own website which functions as a control hub for user(s) and