A recently published Ford patent application suggests an unusual way to boost EV range.
Published by the United States Patent and Trademark Office (USPTO) Jun. 8, 2023 (and originally filed Dec. 8, 2021), the application is titled "Electrified Vehicle Roof-Mounted Battery Backup"—and it's exactly what it sounds like.
The first image shows a Bronco-like SUV with a roof carrier connected to a charge cable. The idea is that a supplemental battery pack could be strapped to the roof of an EV and used as a backup power source when charging stations aren't available.
Ford roof-mounted EV backup battery patent image
Further images detail a streamlined housing for the backup battery, similar to conventional rooftop cargo carriers. It could incorporate air channels for battery cooling, and could use standard roof rack attachments, according to the application. That would also make it removable, although wrangling a heavy battery pack on or off a car roof does not sound like a fun task.
Ford isn't the first automaker to suggest that EV drivers could battle range anxiety by bringing along extra battery packs. A Rivian patent for a removable battery surfaced in 2019, and CEO RJ Scaringe mentioned production plans later that year, but so far the company hasn't moved forward with the idea.
It's unclear if Ford will either. A patent application isn't a product plan, and even if it does make it to production, the roof-mounted battery described here would only make sense as an overlanding or off-roading accessory. On long road trips the increased weight and aerodynamic drag would likely negate most of its benefits.