SEATTLE – Computer makers are recalling 100,000 laptop battery packs made by Sony Corp. after 40 reports of overheating, according to a U.S. Consumer Product Safety Commission notice Thursday.

The voluntary recall applies to certain Sony 2.15Ah lithium-ion cell batteries made in Japan and sold around the world in laptops made by Hewlett-Packard Co., Dell Inc. and Toshiba Corp.

Some incidents involved smoke or flames, according to Sony. Twenty-one of the reports claimed minor property damage, and small burns were reported in four cases.

Sony blamed two factors for the defects: adjustments on its manufacturing line from October 2004 to June 2005, which may have affected the quality of cells in certain production lots; and a possible flaw in the metal foil for electrodes.

The company said no reports have been filed for batteries made after 2006 and noted that the recalled units are a small fraction of the more than 260 million it has shipped over six years.