The company plans to include the fuel cell in its mobile products by 2004.
The fuel cell generates power by a chemical reaction between hydrogen and oxygen. There are two methods of using hydrogen in a fuel cell: one is to use methanol, from which hydrogen will be extracted; and the other is to directly use the hydrogen itself as fuel.
The former method generates more power but needs a large device, made up of 300 to 1000 parts, inside the cell to extract the hydrogen from the methanol.
Casio has shrunk the device to the size of a postage-stamp by combining the parts into one chip, allowing it to use the methanol-hydrogen method in small fuel cells.
The company holds about 120 patents on the fuel cell technology. Once the cells are in mass production, the price should be around the same as for a conventional lithium-ion battery.
Other companies including Toshiba, Hitachi and Motorola are developing similar technologies. Toshiba aims to commercialise its fuel-cell technology for PDA products within two years, the company said.