Volkswagen, whose drive to develop a "solid-state" electric car battery with U.S. startup QuantumScape has been dogged by delays, is casting its net wider in pursuit of the potentially game-changing technology.

The German auto giant is holding talks with France's Blue Solutions, which already produces solid-state batteries for Daimler electric buses, about adapting the design for cars, said a source with direct knowledge of the discussions.

VW and Blue Solutions aim to reach a joint development agreement in the coming months, according to the source who asked not to be identified as the talks are private.