“We’ve got to scale battery production to crazy levels that people cannot even fathom today.”

That’s what Elon Musk told analysts back in January. For at least 15 months now, Tesla’s CEO has been teasing his massive fan club with promises to “blow your mind” on a self-styled event he’s calling “Battery Day.” Other companies — most notably, QuantumScape — in recent weeks have tried to steal Musk’s thunder. But now, after numerous postponements, Tesla’s live webcast event is finally here, starting today at 1:30 p.m. Pacific Time time.