Apple Computer and Dell Inc. have recalled batteries in several millions of notebooks due to explosion hazard of lithium-ion cells for batteries apparently supplied by Sony. Similar batteries are used in notebooks from Lenovo and HP and the failure may be widespread. A number of notebooks from Apple and Dell have already exploded.

Sony said in an official statement that the recall arises because, on rare occasions, microscopic metal particles in the recalled battery cells may come into contact with other parts of the battery cell, leading to a short circuit within the cell. Typically, a battery pack will simply power off when a cell short circuit occurs. However, under certain rare conditions, an internal short circuit may lead to cell overheating and potentially flames, the company indicated. The potential for this to occur can be affected by variations in the system configurations found in different notebook computers.

Apple Computer has recalled batteries for 1.8 million of laptops, whereas Dell has recalled 4.1 million batteries with potentially dangerous cells. Sony currently estimates that the overall cost to Sony in supporting the recall programs of Apple and Dell will amount to between Ґ20 billion and Ґ30 billion (between $170 and $255 million). This overall cost is an estimate based on the costs of replacement battery packs and any other related costs to be incurred by Sony.

Media reports claim that Sony’s cells were also used in notebooks by HP and Lenovo, even though these two companies have not recalled anything yet. It is uncertain whether Sony’s own notebooks contain potentially dangerous cells and whether the company plans any recalls.

Sony said it had introduced a number of additional safeguards into its battery manufacturing process to address this condition and to provide a greater level of safety and security.

“We believe the issue has been addressed to the satisfaction of our customers,” the company claimed.