At Tesla’s Battery Day event, CEO Elon Musk made some big announcements: the company’s moves toward eliminating cobalt in its batteries, a new Plaid powertrain for the Model S that could get to speeds of 200 mph, and a new cathode plant to streamline its battery production. And, with the new battery technology, Musk has said Tesla will make a $25,000 car.
$TSLA, -5.59%, which had gained more than 4% after an upbeat post-shareholder-meeting presentation, went down as soon as Chief Executive Elon Musk said that some of the innovations showcased at the event were “close to working” and some three years away from fruition. Shares were recently down 6.8% in the extended session....