The recall of nearly six million notebook PC batteries by Dell and Apple in August, and more than 500,000 by Lenovo and 830,000 by Toshiba in September due to fire risk has caused many people to look twice at their computer batteries. However, few alternatives to today's lithium ion batteries exist yet: promised fuel-cell technology for notebooks remains stuck in research labs.

The Dell and Apple recalls, which followed online pictures of flaming Dell laptops, were impressive both for their size and scope. The US Consumer Product Safety Commission called the initial Dell recall the largest consumer electronics recall in history, affecting PCs shipped worldwide.

Sony Energy Tech, which manufactured all the batteries in question, points to problems with cells, several of which are contained in each battery pack. Sony accepts some responsibility and says it will help pay for the recall - which could cost the company up to $250 million - but the root cause of the problem remains unclear.

Sony points to tiny metallic particles present inside the batteries after manufacturing. If those particles punctured a cell wall, they could cause a short circuit and thus a fire, the company says.

"You try to eliminate that in the manufacturing process, but to eliminate them 100 per cent is very difficult," says Rick Clancy, a spokesman for Sony. "Usually when you have a short circuit, it might lead to a battery powering down, so you'd have a dead battery, but other times it could lead to incidents including flaming."

The troubles prompted the IPC (a trade association representing component makers) to begin work in September on a new industry standard for lithium ion battery production and quality control. Dell, Hewlett-Packard, Lenovo and Polycom, among others, are helping craft the standard.

"Our message is that public safety comes first," says Tony Corkell, quality and standards executive at Lenovo. The group aims to publish the standard by the second quarter of 2007.

The recalls have also prompted the question, is there a better alternative to lithium ion? Not right now, but maybe in a few years. Vendors such as Panasonic and Casio continue to research fuel cell technology.

Panasonic still claims lithium ion is a "very good technology" but is also working on fuel cells, says Brian Kimberlin, director of consumer marketing at Panasonic Battery Corp of America.

Fuel cells can typically keep a PC running for several hours on a small squirt of methanol. Earlier this year in Tokyo, Casio demonstrated a fuel cell for notebook PCs, early versions of which the company said would ship in 2007. Casio claims the prototype could work about four-times longer than a comparably sized lithium ion battery.

Many laptop makers are pursuing the technology, but it remains too immature for commercialisation. Also, the airline industry has yet to approve fuel cells for use aboard planes. Despite earlier predictions by some laptop vendors that fuel cell–powered machines would be on sale by now, they remain a year or more away from shipping.