Dell is recalling over 4 million notebook computers because of a risk of overheating batteries bursting into flames or exploding.

So far, Dell says it’s heard of six batteries, which are made by Sony, since the beginning of the year that have overheated or burst in to flames.

The affected notebooks are from the Latitude, Inspiron, Precision, and XPS series bought between April 2004 and July 2006.

“In rare cases, a short-circuit could cause the battery to overheat, causing a risk of smoke and/or fire”, said a Dell spokesperson.

At least 2.7 million of the recalled computers were bought in the US, while the total number makes up at least 18% of the 22 million Dell notebooks sold during the time frame.

Analysts say that because the batteries were supplied by Sony, the company will most probably have to pay some of the battery replacement expenses.

Although it’s not known if Sony batteries in other manufacturers’ laptops may have similar problems, it’s thought that the combination of the batteries and the recharge system provided by Dell is at the root of the problem, thereby making it Dell-specific.

Dell has set up a special website to deal with the recall