"The only hard problem of electric vehicles is the battery - which is third party in Teslas". No the entire system efficiency is whats hard and is why Tesla is

"The only hard problem of electric vehicles is the battery - which is third party in Teslas". No the entire system efficiency is whats hard and is why Tesla is way in front of the competition with regards to performance and range. Batteries have so far been a commodity - 18500 & 21700s, its only now that Tesla is starting to focus on that part of the system in reference to Battery Day.