.... 'Swap an empty tank for a full one'.
The idea of swapping a depleted battery
pack for a charged one and driving on has been around for ages. It's getting it to work that's hard. An old battery
pack is not the same as a new one.
One option is that the battery
pack is owned by the driver but that seems doomed to failure - when you swap the battery pack, you might be handing in your 3-month old pack and getting an eight-year old in exchange. It's like driving in with a 10,000 mile engine and driving out with a 200,000 mile one. Who would do that?
The other option is that the battery pack is just leased/rented to the driver and so swapping it is not too big a concern for the user. However this wouldn't encourage the user to take much care of the battery pack and how they're looked after makes a big difference to how long batteries last.
Maybe with modern controls it's possible to make a careless-driver-proof battery, but if so that would be an important part of this proposal.