While we may have to wait 20 years or longer for cars powered by fuel cells to become a familiar sight, Toshiba has already developed a prototype direct methanol fuel cell (DMFC) for portable PCs.
Considering the increasing demands made on a power supply by faster CPUs, higher resolution displays and wireless connectivity, the lifespan of lithium-ion batteries are too limiting.
Fuel cells are widely seen as a replacement for lithium-ion batteries, but companies working on their development have had to overcome the problems of miniaturisation and fuel delivery, which is what Toshiba has now achieved with its DMFC. The fuel cell was displayed at the CeBIT exhibition in Hanover, Germany, which ended yesterday.
According to Toshiba, methanol in a fuel cell delivers power most efficiently when it is mixed with water in a 3%-6% methanol concentration, which requires a fuel tank that is much too large for use with portable equipment.
The company overcame this by developing a system that allows a higher concentration of methanol to be diluted by the water produced as a by-product of the power generation process, allowing methanol to be stored at a much higher concentration. This achieves a fuel tank that is less than one-tenth of that size.
The prototype can operate for about five hours on 50cc of high concentration methanol and measures just 275mm by 75mm, weighing 900g. It includes a 72g cartridge containing 50cc of fuel.
Most of the big electronics companies are working on fuel cells in one way or another, with some - like Intel - going a step further and investing millions of dollars in start-up companies like PolyFuel and Neah Power Systems to accelerate development.
The advantages of this type of power system are numerous. Fuel cells that last far longer than rechargeable batteries would free laptop computer users and television camera crews, for example, from the need to lug heavy and expensive backup battery packs.
A study shows that one kilogram of methanol can deliver one watt of power for 6 000 hours, whereas a fully charged lithium-ion battery will last for 150 hours.
The company has said that it will continue development of DFMC technology and the challenge is to perfect the technology to achieve a suitably long lifespan with a conveniently sized cell.
Another possibility that the DMFC offers is the promise of "hot swapping" - the ability to switch to a fresh power source without turning off a computer or phone. The user would simply add a new fuel cartridge to the cell before the reservoir runs dry.
Toshiba has given the DMFC the same electrodes as found in lithium-ion batteries, allowing it to connect directly to a PC or other portable device in the same way as a lithium-ion battery.
The company is targeting product commercialisation of the DMFC by 2004.
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