Most of the manufacturers have demoed variations on that theme. The big problem is that you have to get all the manufacturers to agree to use same battery pack on all their models. If every gas station has to keep a stock of dozen different batteries with a dozen different swapping procedures it will get too expensive to implement.

Another aspect is a question of manpower. I don't know what it's like in the rest of the world, but here in Sweden more and more gas stations are completely unmanned. And at the ones that do have staff they're are basically just there to run the large convenience store. No gas station today employs people who actually knows anything about cars. Unless this procedure is completely automated, it will require the gas station to take on extra, trained, staff.