Click to enlarge

The fuel cell was first shown at the International Consumer Electronics Show in Las Vegas in January 2006. Then it was the size of a laptop battery, but the latest version, due to be unveiled later this week at an event in Japan, is half the size, Panasonic said.

The new version has a volume of 270 cubic centimetres and can deliver an average power of 10 Watts with a peak output of 20 Watts, Panasonic said. It weighs 320 grams.

On a 200cc charge of methanol it should be able to deliver power for 20 hours, which is longer than lithium ion batteries used in laptop PCs today. When the methanol gets low all that's required is a quick refill, which is seen as one of the key advantages of direct methanol fuel cells (DMFCs). They are also viewed as more environmentally friendly because the only by-product is a little water and carbon dioxide.Panasonic says it hopes to have the cells on the market by the end of 2012.

Panasonic has also developed a stand-alone DMFC charger that has a couple of USB power outlets and can be used to recharge dead gadgets such as iPods and cell phones when away from a power socket. The recharger is slightly larger at 360cc and weighs 350 grams.