Elon Musk's dream of producing 20 million Teslas per year hangs on whether or not it can pull off a major shift in battery tech

• Tesla wants to make lower cost electric vehicles, as a key part of its plan to fend off challenger.
• But it needs to invest in low-cost, cutting-edge battery tech to see that vision through.
• A mineral research firm says Tesla is not doing enough to control the costs of its batteries.

Elon Musk's ambition to sell 20 million Tesla vehicles per year by the end of the decade is no joke. So it was strange that its long-awaited plans for a low-cost electric vehicle was a complete no-show during the launch of Tesla's latest master plan in Texas last week.