Tesla made a splash last week with its proposed $5 billion "Gigafactory" and its eye-popping numbers: a 10 million square foot facility on an entire land area of 500-1,000 acres, with output of 35 GWh/year of battery cells and 50 GWh/year of battery packs by 2020. That'll be enough to support 500,000 of the company's forthcoming Gen-3 vehicles, compared with a little over 20,000 annual demand for its cars today. By comparison, the entire lithium-ion battery supply-chain produced about 34 GWh in 2013, the vast amount going not to electric vehicles but consumer electronics.