Future Teslas will have batteries that double as structure, making them extra stiff while improving efficiency, safety and cost

Tesla has fundamentally redesigned the way that its battery packs integrate into their vehicles, turning them into structural elements of the car, rather than just fuel sources on their own. At Tesla’s Battery Day event on Tuesday, Elon Musk compared this to how commercial aircraft used to load fuel into tanks that were contained within the wings, but that were essentially bolted onto internal structure — later on, they realized much greater efficiencies in how much fuel could be car