Volkswagen has been prototyping an autonomous charging robot for electric cars.

The idea is that the robot "lives" in a docking station--located in a parking garage, for instance--alongside multiple battery packs on wheels, all plugged into the wall and charging. When an electric car is parked in the facility, and the driver requests a top-up via an app, the robot does this:

To accommodate multiple cars in need of charging, the robot then leaves the battery pack to complete the charging process while the robot itself returns to base, awaiting its next charging assignment:

Once a car is topped off, the robot returns to retrieve the battery pack.

Volkswagen reckons this is a cheaper way to have charging capacity that can cover a large area of parked cars, without having to install charging points at each space. It also simplifies things for the driver. In VW's vision, their system will "enable the operators of parking structures to quickly and simply 'electrify' every parking space by utilizing the mobile charging robot," the company writes. "This reduces any construction work needed, at the same time reducing the potential cost."

The robot and system have successfully been prototyped and are headed for production. VW says it will hit the market early this year.