DETROIT - General Motors Co. said Monday it will spend $8 million to double the size of its suburban Detroit lab that engineers and tests electric vehicle batteries.

GM said the expansion of the facility in Warren, Mich., won't create any new jobs, but will allow the automaker to centralize its battery testing and do tests in-house rather than with outside contractors.

The expansion will also allow GM to do safety and abuse tests, manufacturing engineering, charger development and heat tests at the lab, spokesman Brian Corbett said. In addition, areas in the lab that were previously used for engine testing will be renovated for battery development.

"This addition will benefit consumers by helping us put cleaner, more efficient vehicles, including the Chevrolet Volt electric vehicle with extended range, on the road more quickly," GM executive Micky Bly said in a statement.

Construction will start this month and the expanded lab is set to open this summer, GM said. About 1,000 engineers now work on electric vehicle development at GM, and the company has 40 to 50 openings for more.

The expansion comes as GM and other automakers start selling electric vehicles to the public. GM plans to begin selling the Chevrolet Volt in December, while other automakers including Nissan Motor Co. plan to sell electric cars around the same time.