This is the first time that Sony revealed the prototype of a practical fuel-cell system including, for example, a secondary battery and control circuit. The company exhibited the evaluation results of the system at Small Fuel Cells 2008, which takes place from April 30 to May 2, 2008, in Atlanta, Ga.

As for the fuel cells for mobile devices, Sony has already announced the evaluation results of a fullerene-type solid polymer electrolyte membrane and MEA (membrane-electrode assembly) developed with the membrane. This time, the company expects to commercialize the new fuel-cell system.

"We have been aiming to mount (a fuel-cell system) in mobile devices and finally reached a level of commercial design," an engineer for Sony Material Laboratory said.

The laboratory plans to commercialize the system for mobile devices consulting with the operation division of Sony.

The new fuel-cell system is direct methanol type and uses methanol as fuel. Also, it is an active fuel-cell system, which controls fuel supply with a pump. The system is hybrid type with the output supplemented by a Li-polymer secondary battery. And it can deal with steeply rising peak powers of mobile devices.

Though Sony did not reveal the output density of the system, its instantaneous output can be as high as 3W, the company said.

"3W is pretty enough for peak powers of mobile devices," an engineer for Sony Material Laboratory said.

Also, its use efficiency of energy is high enough that 14 hours of 1seg movie can be continuously played by general mobile phones with 10mL of methanol.