> maturing technology for swapping batteries as a refuelling strategy

This seems like a non-problem to begin with. There are electric semis with a 500 mile range, which at 60 MPH is over 8 hours of driving, i.e. the legal maximum in most places. The same trucks can also add 300 miles of range in 30 minutes, which adds five hours of driving in the time it takes for a typical lunch break. Why do you even need to swap the batteries?