The executive is now hiring for a stealth startup involving batteries and powertrains.

Tesla's top battery pack engineer has departed as the company continues to deal with Model 3 production trouble.Jon Wagner served at Tesla for nearly five years, rising to his most recent position as director of battery engineering. Jalopnik says he left in the past few weeks, but further details have not yet surfaced.

A LinkedIn profile suggests Wagner is now actively recruiting workers to join a stealth startup focused on batteries and powertrains.

Tesla recently blamed problems with battery module assembly for delaying the Model 3 ramp-up schedule by three months. The issue involved a subcontractor, but Tesla CEO Elon Musk promised to avoid "externalizing" responsibility.

"Really it's our fault for picking the wrong supplier and then not realizing it until way late in the game," he told an analyst after releasing Q3 financials.

It is unclear if Wagner was among the Tesla executives tasked with avoiding such problems.