 In June 2011 a Volt that had been subjected by the National Highway Traffic Safety Administration ( NHTSA ) to a 20 mph ( 32 km / h ) side pole impact crash test followed by a post @-@ impact rollover , caught fire three weeks later in the test center parking lot , burning nearby vehicles . The battery was found to be the source of the fire . After the fire , both Chevrolet and the NHTSA independently replicated the crash test and a subsequent vehicle rotation procedure to test for any fluid leakage , but in their first attempt they could not reproduce the conditions under which the battery pack ignited . The NHTSA said it had " concluded that the crash test damaged the Volt ’ s lithium @-@ ion battery and that the damage led to a vehicle fire that took several weeks to develop . " In further testing of the Volt 's batteries carried out by NHTSA in November 2011 , two of the three tests resulted in thermal events . One battery pack was rotated 180 degrees within hours after it was impacted and began to smoke and emit sparks after rotation . In the other case , the battery pack that was crashed @-@ tested one week earlier and that had been monitored since the test caught fire . The NHTSA then took an uncommon step on November 25 , 2011 and opened a formal safety defect investigation " without any data from real @-@ world incidents " to examine the potential risks involved from intrusion damage to the battery pack in the Chevrolet Volt . After the initial Volt fire , the NHTSA examined the Nissan Leaf and other plug @-@ in electric vehicles and said its testing “ has not raised safety concerns about vehicles other than the Chevy Volt . ” 
