Elon Musk says Tesla will achieve a battery cell cost of $100 per kWh by the end of 2018 if commodity prices remaining stable. Elon Musk sees Tesla batteries becoming cheaper than $100 per kWh for the overall battery pack in less than two years.
Tesla should achieve a 30% improvement in volumetric energy density within 2 to 3 years using current proven technology that needs to be scaled and made reliable.
Tesla plans up to 12 Gigafactories ultimately (combined battery, drive-train and vehicle production).
They have a path to 3x to 4x improvement in Supercharging times over the longer term.