Toshiba Corp. (Japan) announced that it developed and manufactured a direct methanol fuel cell (DMFC) for its PDA Genio on a trial basis. The new material lowers the loss of voltage that is caused on the positive electrode, which improves the performance. The company achieved an output power density of 25 to 30mW/cm-sq at cell temperatures between 30 to 40 degrees C, and 110mW/cm-sq at 90 degrees C.
The prototype cell outputs 5W on average and a maximum of 8W. Measuring 127mm x 105mm x 25mm, the fuel cell allows continuous operation five times longer than with an intrinsic type of lithium-ion secondary battery. Specifically, a continuous operation indicator shows approximately 40 hours of operation instead of the eight hours observed with conventional cells.
According to Toshiba, the fuel cell can be further miniaturized through optimization of the cell structure and its peripherals. The weight of the prototype is about 500g, but weight saving is possible down to 200g by alternating parts made of carbon or metal to plastics. A single cell generates between 0.4V to 0.5V, and the utilization factor is about 90 percent as 10 percent or so of fuel is lost at a crossover. Power gained from one gram of fuel is about 2Wh with efficiency of power generation around 33 percent.
Toshiba aims to put the fuel cell on the market by 2003.
