Tesla has filed a patent application for a machine that will enable technicians to swap EV battery packs in as little as 15 minutes. The EV-maker initially toyed with the idea of building rigs that can quickly replace its cars' battery packs back in 2013 -- it even demoed the system at an event. That didn't quite pan out, but it clearly hasn't given up on its plans of providing customers a quick way to get their packs swapped out. As Electrek notes, the new design is more compact than the one it showed off a few years ago and could even be mobile, probably so it could easily be placed in strategic locations where Superchargers aren't available.