In 2019, electric truck maker Rivian filed a patent for a “removable auxiliary battery” that would fit into the front third or so of the truck bed. This patent was granted in 2020, so Rivian currently has a patent on this technology.

The patent is described as:

• An electric vehicle system for transporting human passengers or cargo includes an electric vehicle that includes a body, a plurality of wheels, a cargo area, an electric motor for propelling the electric vehicle, and a primary battery for providing electrical power to the electric motor for propelling the electric vehicle. An auxiliary battery module is attachable to the electric vehicle for providing electrical power to the electric motor via a first electrical connector at the auxiliary battery module and a second electrical connector at the electric vehicle that mates with the first electrical connector. The auxiliary battery module can be positioned in the cargo area while supplying power to the electric motor, and can be removable and reattachable from the electric vehicle. The auxiliary battery module includes an integrated cooling system for cooling itself during operation of the electric vehicle including a conduit therein for circulating coolant.

We aren’t patent lawyers here, but this sounds awfully similar to Tesla’s “range extender.” The obvious potential differences we can find are if the range extender doesn’t have integrated cooling, which is unlikely, or if the range extender isn’t removable, which doesn’t seem to jive with the statement that it is only for long trips or with the marketing showing it as an optional add-on (if that were the case, why not just offer different battery sizes?).

Tesla itself has many patents (and is still pursuing more of them) but has pledged not to “initiate patent lawsuits against anyone who, in good faith, wants to use its technology.” It announced this in a 2014 blog post and followed up by saying that it thinks several companies are using its patents.

So next, the question is: is Tesla’s solution different enough to avoid Rivian’s patent protection? Has Tesla licensed the idea from Rivian, and we just haven’t heard about it yet? Or will Rivian return Tesla’s “good faith” and not initiate a patent lawsuit against Tesla if it does feel like it has a good enough case to say that Tesla’s range extender infringes on its patent?