That's not the way trademarks work.. Tesla has a trademark only in the fields they compete in: solar, cars, batteries. They can't stop you from starting Tesla Coffee Shop, or (in this case) Tesla VR suit.
Those are not trademark categories. Here's a list:
http://www.tmweb.com/trademark_classes.asp
In particular note Class 09, which covers solar and batteries AND this haptic suit.
The court will start by asking one question along the lines of, "Is there a good chance that a typical customer in the market for either product will be confused regarding the origin of the goods?" The weasel words in that question will leave plenty of room for argument on both sides.
(IANAL, but have had cause to look into this question recently.)
Trademarks don't get you rights to every market that utilizes the type of item you sell.
A dash of legal ambiguity is often enough for a deep-pocketed company to cause a lot of pain, regardless of the letter of the law.
There is no battery trademark category. Only electronics, which covers both batteries and this suit.
So yes, they do need to change their name.