Toshiba Develops Compact Fuel Cell for Mobile Devices

January 28, 2002 by Jeff Shepard

Toshiba Corp. (Tokyo) announced that it has developed a new compact fuel cell for use in mobile devices. The invention of new materials for electrodes of the cell has paved the way for improvement of the output power density and the voltage. The new material lowers the loss of voltage that is caused on the positive electrode, which improves performance and achieves an output power density of 25mW to 30mW/cm-sq at cell temperatures between 30 to 40 degrees C, and 110mW/cm-sq at 90 degrees C. Toshiba aims to put the fuel cell on the market by 2003.

The increase in voltage has a direct bearing on the efficiency of power generation. The prototype cell outputs 5W on average and a maximum of 8W. Measuring 10cm-cu, the fuel cell allows continuous operation five times longer than with an intrinsic type of lithium-ion secondary battery. The dimensions are 127mm x 105mm x 25mm, and the volumetric capacity is 333cm-cm.

According to Toshiba, the cell can be further miniaturized through optimization of cell structure and the peripherals. The weight of the prototype is about 500g, but can be reduced 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 of the fuel is lost at a crossover. Power gained from 1g of fuel is about 2Wh with efficiency of power generation around 33 percent. In addition, a tank can be further reduced by using fuel of a high concentration and by installing a mechanism for diluting the fuel for downsizing.