No cost advantage in buying from Panasonic?
Hmm... does Panasonic have a monopoly in batteries, or is the battery a commodity? What pricing power does Panasonic have?
My understanding is that a battery is a commodity and prices will come down. You can make your own, but isn't it more important to make the best car, since they are selling cars and not batteries?
Tesla makes the best car. Best electric car, but also the best car of any variety. The absolute best.
Someone will come along and sell them a cheaper battery if Panasonic rips them off. Maybe they'll begin making batteries themselves -- but why not let somebody else make the battery to their specs?