Range of over 400 miles?
Yes, that's right.
The electric pickup truck has a patented add-on battery that extends range beyond 400 miles. And here we thought 400 miles was already way more than enough.
Have a look at the patent image below. We've included the title and abstract too:
Electric Vehicle With Modular Removable Auxiliary Battery With Integrated Cooling
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.
It seems the Rivian range-extending pack (officially called the Auxiliary Battery Module) bolts into the bed of the pickup truck and can be connected/activated when needed.
The idea is okay, but in reality, that battery is going to cost quite a bit and it surely won't be light.
Rivian Forums adds:
The battery is removable and reattachable to the vehicle, supplying power to the electric motor by being positioned in the cargo area (i.e. the cargo bed of the R1T). Once attached, the vehicle can automatically detect the battery module and make necessary adjustments according to a set of multiple predetermined features sets that determine driving performance, suspension characteristics, braking performance/sensitivity, steering ratio, etc.
Here's the initial spec sheet for the Rivian R1T. Note that the removeable battery pack would extend the range of all versions, but only the top-line R1T would exceed 400 miles with this added pack. By exactly how much though is still unknown:
Source: Rivian Forums