The Tesla (NASDAQ:TSLA) Cybertruck arrived last week. So far, one thing is clear. It isn’t a reason to bet on TSLA stock. Concerns regarding the new electric truck’s mass appeal and the company’s ability to scale its production have caused share prices to struggle, even as enthusiasm for the Cybertruck has surged across the internet. On top of that, it has also been revealed that to achieve the promised range, the Cybertruck requires a separate battery pack. This isn’t good news for Tesla, but today things took a turn for the worst. Fellow electric vehicle (EV) producer Rivian (NASDAQ:RIVN) has already patented a Cybertruck range extender device. In fact, it successfully did so years ago.

Realistically, Tesla can’t afford any further setbacks, as the Cybertruck hasn’t been the growth catalyst investors were looking for. Now, it could be facing a legal battle if Rivian’s device is as similar to the Cybertruck range extender as it sounds.

Tesla Cybertruck Range Extender: What to Know

Range anxiety on the part of consumers is one of the biggest hurdles facing the EV sector. Tesla’s Cybertruck range extender could help combat that, although the fact that the company didn’t initially disclose that it would be necessary feels somewhat misleading. It certainly doesn’t help that one of Tesla’s chief rivals appears to have a patent on the same technology. This could pose more problems, especially if Rivian decides to file a lawsuit against the large EV producer.

Elon Musk has stated that the Cybertruck range extender is only “for very long trips or towing heavy things up mountains.” That makes sense in theory, as mountain travel might be one of the only things the large vehicle really makes sense for. However, that doesn’t change the fact that it could easily be infringing on Rivian’s technology, as the two devices sound highly similar. After taking a closer look, Electrek reported:

“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?).”

Besides clarifying the range extender’s purpose, Musk hasn’t provided much detail on it, nor has he commented on Rivian’s patent. It has yet to be established if Tesla’s design is different enough from Rivian’s to avoid a patent lawsuit. But if the EV startup does decide to take legal action against Tesla, it may make it even harder to keep up with Cybertruck deliveries. Given the problems that Tesla is facing already, that’s the last thing it needs.

The Road Ahead

There’s a key lesson for investors in this latest development. For all its flash, Tesla isn’t necessarily making the best EVs or turning them out with the most efficiency. Rivian patented its removable auxiliary battery in 2019 and received the patent in 2020. During this time, Tesla was still struggling to meet its own deadlines for the Cybertruck.

This shows that Rivian is among the companies producing better trucks than Tesla. That isn’t likely to change in the era of the Cybertruck. The company has been called the “Tesla killer” before, and that argument could be about to get even stronger.

On the date of publication, Samuel O’Brient did not have (either directly or indirectly) any positions in the securities mentioned in this article. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.