Toshiba has developed a prototype direct methanol fuel cell (DMFC) that it claims will end the need for rechargeable batteries on portable PCs.
The new fuel cell had an average output of 12 watts, a maximum output of 20 watts last about five hours with 50 millilires of fuel, Toshiba said. It runs on replaceable methanol cartridges.
Methanol in a fuel cell delivers power most efficiently when mixed with water in a three per cent to six per cent concentration.
This had previously made the fuel tank too large for portable equipment, Toshiba said. However, the new cell included a system whereby the methanol was diluted by water produced in the power generation process. This process allowed the methanol be stored at a higher concentration, allowing the fuel tank to shrink to a tenth of the size previously needed.
The PC communicated with the fuel cell, giving information on its operating status, so that the fuel cell could balance power demand and supply, Toshiba said. Sensors in the cell monitored methanol concentration and told users when to change the cartridge.
The fuel cell can be directly connected to a PC or other portable device in place of a lithium-ion battery. Two cartridge sizes have been developed: a 120gm, 100ml cartridge offering 10 hours of operating time, and a 72gm, 50ml version giving 5 hours of operation.
The fuel cell itself weighed 900 grams, Toshiba said.
The DMFCs are expected to go on sale in 2004.