Ford has filed a patent application for an electric vehicle backup battery. A user on a forum dedicated to the F-150 Lightning electric truck apparently discovered it in the U.S. Patent Office database this weekend.
According to the authors of the patent, the spare power cell pack is supposed to be mounted on the roof. The images show it mounted on a Bronco, which currently doesn’t have an all-electric modification. Then again, Ford CEO Jim Farly hinted two years ago that the company could be interested in producing such a Bronco version.
The reserve battery is plugged to the main one with the help of a charging cord, implying inevitable power transmission losses. The casing has cooling vents that an automated hatch system is supposed to close shut automatically whenever there is a risk of water or dirt incursion. It is assumed that such batteries would primarily be useful in areas without charging stations – for example, in long-range wilderness trips. They can be detached and removed from the vehicle when not in use.
It is probably worth remembering that all modern-day battery designs are inherently heavy. It is unclear how Ford will deal with the added strain on the frame of the SUV and its roof. A potentially greater concern arises from making the off-roader top-heavy and thus more prone to rollover. Last but not least, there is the well-known curse of EVs: more weight means less range, so piling up batteries is bound to have diminishing returns.
Ford has not commented on the patent so far, and there are no production plans as far as we are aware.