8.8.2001
"HydroGen3" Fuel Cell Study Moves Closer to Volume Production

At the Frankfurt Motor Show (September 13 - 23), Opel will present the pioneering concept of the HydroGen3 fuel cell study with the aid of a cut-away scale-model.

The drive train of the new fuel cell Zafira has been improved to allow optimum packaging of the vehicle's components. The new HydroGen3, which, like its predecessors, is based on the successful Zafira compact van, has been developed by Opel and GM's joint Global Alternative Propulsion Center (GAPC) with sites in Mainz-Kastel in Germany and Warren and Rochester in the USA. In the coming months, several road-going prototypes of the five-seater fuel cell Zafira will undergo rigorous heat, cold, height and stamina trials.

The primary aim of the HydroGen3 development was to improve the performance and day-to-day use of the propulsion system. An advanced fuel cell system makes the high-performance buffer battery - which was required for HydroGen1 - redundant. Improvements of the architecture of the entire fuel cell system obviated the need for additional external humidifying components for the cells, creating yet more extra space and weight savings. The electrical traction system has also undergone further development, and is now more compact. The complete module, comprising the DC/AC converter, electric motor, and transmission with park position and differential weighs only 92 kilograms. The total weight of the vehicle was reduced to 1590 kilograms. The hydrogen for the fuel cell Zafira is stored in liquid form at a temperature of -253°C. The twin-walled tank has a capacity of 68
liters or 4.6 kilograms of hydrogen. Its interior is insulated against heat conduction by a high vacuum between the exterior and interior walls. Extra layers of thin aluminum foil provide added protection against heat radiation. This volume is sufficient to give HydroGen3 an operating radius of around 400 kilometers.

The fuel cell stack – after further development by the GAPC specialists – consists of a block of 200 fuel cells connected in series. With its dimensions of 472 x 251 x 496 millimeters it is now significantly smaller than the fuel stack used in the HydroGen1. On the other hand, the power density of the fuel cell block – which operates at a pressure of 1.5 to 2.7 bar – has been increased to 1.60 kilowatt per liter or 0.94 kilowatt per.

The stack on board HydroGen3 develops a constant power of 94 kW and a peak of 129 kW. This environmentally compatible powerhouse, in which hydrogen and oxygen react electrochemically to form water at a temperature of 80 degrees Celsius, generates between 125 and 200 Volts of electrical energy, depending on load conditions.

With this highly effective driveline, the fuel cell Zafira travels from 0 to 100 km/h in 16 sec, and has a top speed of 150 km/h. HydroGen 3 is still a prototype - yet it moves Opel/GM's fuel cell vehicle studies close to volume production.