Despite a long series of problems connected to lithium-ion batteries - most recently on Tuesday, when Nokia warned customers that 46 million batteries in its cellphones might be defective - some experts maintain that they are still the best and safest option for running the myriad electronic devices that have come to define everyday life in much of the world.

The sheer number involved in the Nokia replacement programme, which fell short of a formal product recall in which customers are told to return their products, overwhelms previous moves by companies over the last few years to recall batteries in laptop computers.

Yet the Nokia batteries called into question still amount to fewer than half a per cent of the cellphones sold in the past 12 months. Although experts acknowledge that deficiencies must be addressed, they said it was too early to sound the alarm against all lithium-ion batteries, which are used not only in most cellphones and laptops, but also most portable music players and other electronic devices.

Nokia’s move this week follows the recall of more than 10 million lithium-ion batteries for laptop computers in the last 18 months. Those recalls involved computers from Dell, Apple, Toshiba, Gateway, Lenovo, Panasonic and Sony.

Toshiba on Monday recalled another 1,400 computers, its fourth recall in the past year, because of potentially faulty Sony batteries.

Lithium-ion batteries have taken over from other types of batteries over the past decade because they produce a relatively large amount of energy for their weight and because they lose their charge much more slowly that many other batteries. But lithium-ion batteries can overheat, and on rare occasions catch fire, if small particles of dust remain in the battery during the manufacturing process.

These particles can pierce an internal part of the battery that divides it into sectors and that in turn can lead to the overheating, according to experts.

Piercing or dropping the battery or leaving it for too long in a hot environment - like a car on a steamy summer day - can also cause the piercing phenomenon. Matsushita Electric Industrial, the company that owns the Panasonic brand, said in announcing a recall last year that some laptops were at risk if they had been dropped.

As a substitute for lithium-ion batteries, many companies have been experimenting with fuel cells, which produce electricity but need an outside fuel source and have been touted by some as more efficient. But so far, portable fuel cells have struggled to get beyond the testing phase for commercial products and there is unlikely to be any significant consumer debuts in the next 12 to 18 months, said senior analyst at CCS Insight in Solihull, England, Geoff Blaber.

When fuel cells do arrive they will initially be used to power smaller products like wireless headsets before they make it into phones, he said.Fuel cells may also pack dangers. The potential flammability of the fuel used in a fuel cell is still being worked out by those trying to develop a viable fuel cell battery technology for small electronic devices.

“If we move to fuel cells, there are always going to be potential problems on the production line, and recalls are to some extent inevitable when you’re trying to execute and fulfill demands on this scale.” “What is important,” he added, “is that when problems arrive, they’re caught early on in the production cycle and before too many products have been shipped.”

Until now, Garner said, most problems with lithium-ion batteries have been with laptops. “That is because they have a much higher current consumption than mobile phones,” he said. “Mobile phones are heavily optimised to draw low levels of current because most of the time they are basically sleeping.”

Source: IHT