A Chevrolet Volt that was used in federal crash testing recently caught fire a few weeks after the test was administered. A safety investigation is being launched into whether the batteries in the Volt pose a potential safety hazard.

Test car catches fire weeks after crash test

General Motors’ plug-in hybrid, the Chevrolet Volt, was given top marks for safety earlier this year by the National Highway Traffic Safety Administration after crash testing, according to the New York Times. The car received five stars in side impact and rollover crashes and a four-star rating in front-end collisions.

Sometime in early June, according to a statement from the NHTSA, one of the Chevy Volts that was used in testing by the NHTSA caught fire in an NHTSA storage facility after being used in a side-impact crash test at 20 miles per hour in mid-May. According to Reuters, the lithium-ion battery pack was damaged in the crash.

General Motors and the NHTSA have not been able to recreate the fire after subjecting further Chevrolet Volts to crash testing.

GM blames the Feds

The National Highway Traffic Safety Administration is beginning an investigation into post-crash safety for all electric or hybrid vehicles that run on lithium ion battery packs, including the Volt.

According to USA Today, General Motors has stated that the NHTSA did not follow the procedures recommended by the manufacturer for post-crash safety, which caused the fire. The battery pack, according to AutoBlog, should have been drained following the crash. Part of the NHTSA investigation is looking into establishing safety protocols for draining batteries by appropriate parties such as first responders or automotive technicians, as it isn’t recommended that the owner do so.

The NHTSA says electric cars are, statistically, no more at risk for fire than internal-combustion powered cars based on the available data.

At least two other Chevrolet Volts have been involved in fires, but both were involved in vehicles that were charging, whereas the NHTSA Volt was not. One fire, according to the Wall Street Journal, occurred in North Carolina. The other, according to Jalopnik, occurred in Massachusetts. However, investigators believe both were caused by faulty house wiring, not the Volt.

Same phenomenon seen in laptops

A recent Jalopnik post points out that the Volt uses lithium ion battery packs, just like a laptop computer. The batteries comprise banks of small cells. If any cells are damaged or deformed, it can cause an electrical short.

Electrical shorts are the most common cause of electrical fires. The lithium gel that is contained in the batter cells fuels the fire. Jalopnik also points out that massive amounts of Dell and Apple laptops were recalled over incidents of batteries catching fire in a similar manner.

The Nissan Leaf and Tesla Roadster also use lithium ion batteries.