The Volt was parked in a National Highway Traffic Safety Administration lot in Wisconsin following a crash three weeks earlier, Bloomberg says.
The Volt underwent a side-impact crash test, and was then put in the garage for storage.
The agency is also looking into a house fire in Lake Norman, N.C., this month which happened when a Chevy Volt was charging inside the garage. Although it's unclear whether the fire started because of the Volt, because of its charging station, or because of a completely unrelated reason, Duke Energy told customers they should stop charging their electric cars in their home garages until further notice.
General Motors says an April fire in Barkhamsted, Conn., was not caused by the Chevy Volt charging in that garage, either. A 1987 Suzuki Samurai, which had been converted to run on electricity, was also charging in that garage.
GM spokesman Greg Martin believes the Volt is safe and doesn't pose any greater risk than other cars. GM makes the Volt under the Chevy brand name.
GM has developed its own set of steps on how to deal with the lithium ion battery after an accident. Martin said if those protocols had been followed in Wisconsin, there would not have been a fire.
Lithium ion batteries have been a tricky technology for automakers to master, because they have a tendency to heat up when in operation. When Ford developed the hybrid Escape, it had to look for unique ways to cool the battery, and added air vents that passed cool air over the battery to keep it from overheating.
The Volt also has special cooling technology. The battery is large and t-shaped, and cooling plates made by Dana Corp. are located between each battery cell.
It is unclear why the Volt caught fire in Wisconsin.