An InfoWorld article, found via Buzz Out Loud, states that Dell knew about the battery failures that have caused several laptops to spontaneously explode for about 10 months. They had discussed this problem with Sony, but they wanted to hold off the recall until, as a Sony spokesmen puts it, those batteries were

…clearly linked to catastrophic failures causing those batteries to catch fire.

The problem seems to be that small metal particles contaminated the Lithium-Ion Cells. These particles can cause the batteries to fail and in some, albiet rare cases, over-heat and explode.

[Image found via the Sydney Morning Herald]