General Motors is ready to embark on the next stage of Chevrolet Volt development, with road testing for lithium-ion battery packs set to begin at the beginning of July.

GM Vice Chairman Bob Lutz told of the start to road testing in an interview with Reuters yesterday, also discussing plans for the next generation of batteries. Lutz said that the company may not be ready to name a supplier for future li-ion power units until the second half of this year, putting GM slightly behind schedule.

"That may also be a little bit longer now, as we need a better handle on who has the technological capability we need and who is going to have the production capability,