Today, Lenovo and IBM said they will cooperate with the U.S. Consumer Product Safety Commission (CPSC) in a voluntary recall of approximately 526,000 lithium-ion batteries manufactured by Sony for ThinkPad notebooks.
All the programs offer free replacement batteries, and Sony is believed to be footing most of the expense.
Separately, Sony announced it was initiating a global program for the replacement of its lithium-ion batteries.
The company said it would provide more details of the program in the near future after consulting with the U.S. CPSC and its manufacturing partners.
In a statement released today, Sony repeated its earlier engineering analysis for what it believes is the cause of the overheating.
Sony said that 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 possibility of 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 potential for this to occur can be affected by variations in the system configurations found in different notebook computers.
Last month, Lenovo said it was "highly confident" its notebook batteries would not be subject to recall because it configures its battery packs differently from Apple (Quote, Chart) and Dell (Quote, Chart) and tested them with Sony engineers.