Stormy weather was unleashed in Tesla longsville today when the company’s veteran director of battery technology, Kurt Kelty, unexpectedly resigned to “explore new opportunities”, abruptly ending a tenure with the company that stretched for more than a decade, and comes at a critical time for Elon Musk: just as Tesla enters “production hell” days after it delivered its first Model 3 electric car to the general public with a dramatic production ramp up expected in the coming weeks. Kelty joined Tesla in 2006 and was one of the longest-serving executives at Tesla after Elon Musk.