General Motors chief Fritz Henderson has said a new $43 million plant in Michigan will assemble battery packs for the company's forthcoming Volt hybrid. The plant will be based in Brownstown Township, 20 miles southwest of Detroit, and will employ around 100 people, the company said. GM will be leasing the 160,000-square-foot building that will house the plant. The investment will include the cost of renovating the premises, as well as the purchase of new machinery and specialized tools.