I don't know about the "rest of the world" but I would be bet that, in December 2010, when the Volt started selling in the US, far more Americans knew that the word "Volt" related to electricity than had heard of Tesla and knew that that word related to electricity.

For me, the bigger issue was that the name - to me - implied that it was an electric car, not a hybrid, so it felt like unsubstantiated marketing spin.