A few years ago it was Panasonic, and I think they're still fairly big on the LiFePO4 scene. They invest quite a lot in battery R&D as well. I feel like everyone's trying to play catch up now though. I wouldn't pretend to know what the current landscape is like. Chinese production has ramped up a lot, so it might be worth comparing Tesla's latest cells to BYD's. There are also smaller players constantly coming onto the scene - Microvast might be interesting for instance. No idea about the major automotive makers, but I'm sure they're progressing as well.