GM (GM) wants to go electric again.The big automaker unveiled a new electric concept car, the Chevrolet Volt, at the North American International Auto Show in Detroit, according to media reports. The Volt, a plug-in hybrid that could drive 150 miles on a gallon of gas and make trips as far as 40 miles on only electricity, signals GM¿s intentions to get back into electric vehicle production. The automaker was criticized by environmentalists after it ended its EV1 electric car program in 2003. There¿s one problem with the Volt, however: It requires lithium-ion battery technology that could take years to be production-ready. GM shares ended Friday up 60 cents at $30.24.