Chevrolet is an example of a company that tried to dance around the battery vehicle market and likely ended up frustrated enough to just add an engine to get around litigation with the Volt.
I find this unlikely, as the Volt was well along in design and had been a show car before the Tesla Roadster made it to production. Also, it beat the Tesla Model S to production by over 1 year. It was on the road about a month before the Leaf even. The Volt was one of the first (modern) production EVs. In fact, the story might be that Tesla and others tried to avoid breaching patents GM had created with the EV1, not the least of which was the acquisition of Ovonics patents for battery technology, way back in the late 90's.