WASHINGTON, June 22 (Reuters) - The U.S. Energy Department plans to lend up to $9.2 billion to a joint venture of Ford Motor (F.N) and South Korea's SK On to help it build three battery plants in Tennessee and Kentucky, the biggest-ever award from the government program. The conditional commitment for the low-cost government loan for the BlueOval SK joint venture comes from the government's Advanced Technology Vehicles Manufacturing (ATVM) loan program. SK is a unit of South Korea's SK Innovation (096770.KS). The joint venture is building two battery manufacturing plants in Kentucky and one in Tennessee capable of collectively...