The idea is, the electrolyte liquid gets drained, then fresh electrolyte goes in, and boom, ready to drive. I believe the technical challenges to such a system are considerable, because this was proposed at least 40 years ago. Obviously there'd be a need to standardize on a paricular electrolyte...
So, refueling would be like doing a drive through quick oil change. Sounds expensive and labor intensive unless the vehicle is designed with standardized ports for such a thing, and then you’d have to build the infrastructure, all the “oil change” shops.