Patents can be granted for near-trivial variations unfortunately.I don't what the Zappi charger actually does, but they've applied for a patent, so are not saying much.
I would be very surprised if it is anything revolutionary, most likely it is simply monitoring the CPC current (probably also another to check the live current imbalance) and tripping all live & CPC on a detected fault.
So an RCD by another name...or the VOELCB given a current-sensing makeover!