It's being proposed that one could have this battery swapped out "at the supermarket." I barely trust them to not put the soup cans on top of the bread, or break the eggs. I don't think I'm ready for them to tinker with my car. And I've personally witnessed more than one profound mistake at the oil-change centers where presumably trained people have overfilled the crankcase (which blew out the engine seals, ruining a Porsche Turbo 911) or neglecting to tighten the oil drain plug, which fell out onto the highway while driving home (ruining a friend's 3 month old Toyota).

>>how to make the 2 ton battery pack a stressed member

Where did the article say anything about the battery weighing 2 tons? That is outrageously heavy, exceeding the GVW of most cars on the road by 40%, alone! Surely this cannot be accurate.

A triangle shape, or multiple smaller packs could help with the issue or structural rigidity. If they can build around a big aluminum engine block, radiator, etc, a battery pack is do-able.

But I've another bone to pick with this article, and it may be a simple matter of the UK vs US norms. It states the average driver travels about 7900 miles/year. That's less than half the average in the US. Also, it says the UK driver of a "small hatchback" spends around 12p per mile for petrol and this battery tech could drop that to 9p per mile. That's not competitive with current hybrid technology (and the Toyota Prius is a mid-sized car, as well) with a 700 mile per 10 gallon imperial tank. Turbo diesels are nearly as efficient. Why would one change?

The technology just doesn't sound competitive to me, overall.