Casio has become the latest Japanese electronics giant to hop on the notebook fuel-cell bandwagon, today pledging to offer a compact power source for portable PCs in sample quantities in 2007.

Casio's prototype is a 6.5 x 1.9 x 1.8cm unit capable of producing 19.4W of power, yielding a capacity of 882W per litre - the world's highest for a cell aimed at portable products, the company claimed. That means a fuel cell the size of a standard Lithium Ion notebook battery could deliver an operational duration four times as long as that of a conventional portable power source, Casio added.

The cell is rated at 13.9V, but the big number is 280°C - the internal temperature the cell rises to during operation. Casio said the design of the cell packaging means the external surface temperature is a more finger-friendly 40°C. ®