Batteries to run cars. Batteries to store solar power. Batteries ... to prevent blackouts. Everywhere you look in the field of battery technology, Tesla (NASDAQ:TSLA) seems to be there already. The company's even building a battery gigafactory in the Nevada desert to keep its battery empire well-supplied, and one of the reasons for this is that Tesla is rapidly outgrowing its origins as a car company, and finding new ways to make money by building huge, utility-scale energy storage complexes to help electricity companies shore up the stability of their electric grids. It's a lucrative business -- and Lockheed Martin (NYSE: LMT) wants in.