Email from HR with a very simple initial screening and email to coordinate first technical interview. First interview was with the person who would be my mentor. He asked about the projects I have done in the past and asked details about the design decisions, which I was prepared for. He kind of had an abrasive personality and so I was surprised to have a second technical interview with the hiring manager. The manager was very pleasant and the questions were more focus on hypothetical problem solving about thermal runaway.