Tesla is losing a battery manufacturing leader, Jens Peter Clausen, to Zymergen, a synthetic biology company funded by Softbank.

Clausen's move is the latest in a string of executive departures from Tesla. As CNBC previously reported, more than 40 executives have left this year as the company contended with a difficult production ramp-up for its Model 3, punctuated by high-profile antics from its eccentric CEO, Elon Musk. Among those who left are engineering leader Doug Field, now with Apple's self-driving car project, Titan, and Tesla's general counsel Todd Maron.

At Zymergen, Clausen will help the company scale its manufacturing teams, processes and facilities.

Zymergen is experiencing growth "at a pace that I'm not sure has been seen in life sciences," CEO Joshua Hoffman said in a phone interview with CNBC.

Hoffman said his company hired Clausen after an extensive search, in part because of his experience "designing and improving largely automated manufacturing environments."

As vice president of Gigafactory 1, Clausen oversaw a rapid expansion of battery manufacturing at Tesla's humongous plant outside of Reno, Nevada. Tesla manufactures its vehicle batteries and energy storage products there using a mix of automated and manual processes alongside Panasonic, its supplier and partner in the facility. Before joining Tesla in July 2015, Clausen spent more than a decade in manufacturing at Lego, the toy company whose products are often used for prototyping in robotics.

Tesla Gigafactory workers told CNBC this summer that they thought Clausen was on leave, and they weren't sure if he was returning to the company. On Sept. 7, Tesla announced a spate of promotions as part of a broader restructuring. In that announcement, it named Chris Lister as Gigafactory vice president. At that time, Tesla said Clausen had no plans to leave the electric vehicle maker.