RE:Elon Musk open to sell batteries This is the second part. Tesla is also planning to build its own battery manufacturing facility at its Fremont, California, plant under its "roadrunner" project. Batteries are the most expensive and important component of electric vehicles (EV). "The supply could lower the entry barriers for startup EV makers, posing a potential threat to legacy automakers, which have their own platforms," said Park Chul-wan, a South Korean battery expert and a professor at Seojeong University. "The strategy, if successful, will increase the EV market's dependence on Tesla," he said. Musk said in a recent earnings conference call that the real limitation to Teslas growth is battery cell production at an affordable price, and said the company would expand its business with Panasonic, CATL and LG Chem. In 2014, Musk also said Tesla would allow others to use its patents in hopes of speeding up development of electric cars by all manufacturers.