GM to build Cadillac ELR in Detroit

General Motors confirmed Tuesday that it will build the Cadillac ELR extended-range plug-in hybrid at the same plant that builds the Chevrolet Volt and Opel Ampera hybrids.

GM said it will spend $35 million on the Detroit-Hamtramck Assembly plant to add the Cadillac. GM North America president Mark Reuss said production of the ELR is set to begin in late 2013.

We first saw the ELR as the Cadillac Converj concept at the 2009 Detroit auto show. Lately we've been seeing lightly camouflaged test mules in metro Detroit.

GM says the ELR will advance the design theme from the Converj. It will use the same platform as the Volt, including a T-shaped lithium-ion battery pack, electric drive and a generator powered by a four-cylinder gasoline engine.

An electric motor propels the car. When the charge in the battery pack reaches a minimum level, the gasoline engine kicks in to turn the generator to power the motor.

The battery pack will be built at GM's Brownstone, Mich., assembly plant.

By Jake Lingeman