This fuel cell generates electricity by producing hydrogen on the spot. This is achieved through a chemical reaction between calcium hydride sheets and water.
From a sheet with volume of less than 3 cc, this fuel cell can generate 5 Whr of electricity. It can be used for many purposes, from charging a smartphone, to providing back-up power in emergencies.
"This single sheet can fully charge an iPhone once. The sheet weighs about 3 g. If these sheets are laminated and sealed, they last for twenty years. Lithium ion batteries lose their charging ability in 4-5 years at most, so they're not good for emergencies. Because this sheet is a chemical product, it doesn't change as long as the sealing is intact."
A version that can serve as a portable generator, delivering 200 W, weighs just 6 kg, with cartridges weighing 750 g. This can be used for outdoor leisure or emergency back-up. Unlike engine generators, it can be used without producing CO2 or harmful exhaust fumes.
Rohm is also developing high-capacity batteries for seismometers using this fuel cell.
"For example, if you want to put a seismometer in the crater of a volcano, naturally, there's no power supply. Ordinarily, you'd need to carry car batteries, weighing 15-20 kg, up there. Our new fuel cell weighs 3-4 kg, so it's really good. And it can keep generating power for six months."
"In the BtoB business, lots of companies are already working on high-power fuel cells. For mobile use, you have to give plenty of thought to commercial distribution. We're looking for manufacturers who understand the issues, and we're discussing where to sell the fuel and where to sell the fuel cells themselves."