[hwillis]

> From what I've heard from auto engineers I know, using the battery as part of the structure is not really done. Transfering mechanical stresses to the battery is something you just do not do.

This is technically true, but structural batteries are not the same as stressed engines like on a motorcycle. In the latter, the engine fully replaces a frame member with essentially just the engine block. With structural batteries the cells themselves are not taking on any stress (they could, but yeah its not a very safe idea) but the outside containment is stil doing double duty. Its a pretty minor weight savings because the battery case does not need to be as strong as the frame does, but its not fair to say that structural batteries are not done. Even when they are just bolting on to a subframe, they're still usually doing things for frame stiffness.