You're still left with the problem of where the power comes from.
While EV is a fringe technology it is easy to have a few running about. But if 20% of cars were replaced with EVs you'd need to find a lot more electricity than is available now.
Most countries don't have surplus electrical generation and indeed many already have a shortage.
I hate to be so pessimistic when it comes to new energy sources, but I do not see the viability /benefit of a recharging system that requires interchange of an energy storage vessel. Would anyone feel safe with energy tanks that may present a safety hazard? The mechanism that would allow a quick interchange, would be very likely the failure mechanism during collision.