Update: Toshiba offers to exchange 340,000 notebook batteries

Toshiba has offered to exchange 340,000 notebook computer batteries, but said they do not pose a fire hazard. Instead, defective batteries could unexpectedly cut power to the notebooks, causing users to lose unsaved work.

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The batteries, made by Sony, may fail to charge correctly, causing the power to cut off suddenly if the notebook is not connected to a mains outlet, said Toshiba spokesman Keisuke Ohmori.

Reports of lithium ion cells in notebook batteries overheating or catching fire have prompted other computer manufacturers, including Apple Computer and Dell, to issue safety recalls. Dell recalled 4.1 million batteries used in its notebook computers in August, citing a fire hazard, while Apple recalled 1.8 million batteries, warning that they could overheat.

Toshiba's batteries are not at risk of starting a fire, Ohmori said. "There is no such hazardous or related issue," he said.

Instead, Toshiba's problems stem from a defect in the interface circuitry between the battery cells and the computer.

That defect is caused by corrosion, said a spokesman for Sony, the manufacturer of the batteries. An ingredient used in the insulating paper of batteries manufactured between March and May can corrode components in the batteries' charging circuits, causing them to fail, said Sony spokesman Takashia Uehara. The supplier changed the composition of the insulating paper without notice, he said.

Batteries made for other notebook manufacturers also contained the paper, and Sony is working with those companies to see whether there is a problem, Uehara said. He declined to say how many batteries were affected overall.

Toshiba's free battery exchange program covers 11 notebook models sold in Japan, five sold in the U.S. and 12 sold in Europe, including the Tecra A7, Satellite A100, Satellite M50 and Satellite pro M70, Ohmori said. European customers can consult a list of affected computers on Toshiba's Web site.