Ernest Villanueva, previously Sr Manager of Battery Module Design at Tesla, has left the company last year according to CNBC. His LinkedIn profile shows he holds 8 patents including two for localized energy dissipation structures for vehicles and one for battery charging time optimization.
He worked for Tesla since 2006 for the then 3-year-old company, starting as a Sr Mechanical Engineer in their Battery Design Team. At the time, Elon Musk was not yet the CEO of Tesla, but was serving as Chairman of the Board.
He was involved in all battery pack designs over the past 10+ years at Tesla, including 8 vehicles (4 Tesla, 3 Daimler, and 1 Toyota). He also was involved in the designing of Tesla Energy stationary storage products.
Over the past few months Tesla has had to reduce their ambitious production targets for the Model 3 largely due to bottlenecks in the battery module manufacturing and assembly.