DALLAS — Dell Inc. said it will issue free replacement batteries to the owners of 4.1 million notebook computers with batteries made by Sony Corp. that were determined to be at risk of overheating and catching fire.

The Sony batteries were placed in notebooks that were shipped between April 1, 2004, and July 18 of this year.

The battery packs were included in some models of Dell's Latitude, Inspiron, XPS and precision mobile workstation notebooks. Dell planned to launch a Web site overnight that would describe the affected models. Williams said the Web site would tell consumers how to get free replacement batteries from Dell.