The Toshiba DMFC, which measures 22 by 56 by 4.5 mm (roughly the length and width of a woman’s thumb) and weighs 8.5 grams (including 2 cc of methanol fuel inside the tank), is an alternative power source designed to integrate into personal devices such as digital music players, cell phones and digital cameras. Its small size offers freedom to designers and developers of electronic devices. While small enough to work in a mobile phone wireless headset, the DMFC prototype is also powerful enough, according to a Toshiba press release, to “power an MP3 player for as long as 20 hours on a single 2cc charge of highly concentrated methanol.”
DMFCs were heavily developed in the early 1990s (the first fuel cells were invented by Sir William Robert Grove in 1839), but were not embraced due to their then low efficiency, among other problems. The clear advantage, however, was that they ran at very low temperatures (50ºC to 120ºC); in a device such as a laptop, this made the cooling fan and, hence, the additional space and weight requirements, unnecessary.
In addition to working with DMFCs in laptops, Toshiba continued to experiment. Its DMFC works on a passive—rather than active—fuel supply system. Active fuel cells use a pump and fan to deliver oxygen and methanol into the “cell stack” where they react and create energy. Toshiba overcame this by determining that a higher concentration of methanol could be used, which eliminated the need for the pump and the fan; consequently, they’re one-tenth the size.
Toshiba is expected to release DMFC-powered handheld devices on the market during 2005.