Key PointsBYD leads in volume.Rivian is improving, but profitability remains elusive.Tesla generates cash while many rivals still burn it.These 10 stocks could mint the next wave of millionaires › There was a time when Tesla (NASDAQ: TSLA) was the undisputed leader in the EV space, and everyone else was simply trying to catch up. Today, that's no longer the case. China's BYD (OTC: BYDDY) is now the world's largest producer of battery-electric an…