It all started in May when the first Volt battery caught fire at a Wisconsin test facility. The car had been parked in a lot with a ruptured coolant line for three weeks after a basic side-impact test. Three more tests were run last week, resulting in two additional fires. That didn't sit right with the National Highway Traffic Safety Administration. 

The NHTSA is further conducting tests on the 16kWh lithium–ion LG Chem batteries with U.S. Defense and Energy departments, but is also expanding the investigation to all vehicles with battery packs. Although the second fires were results of recreating the situation that triggered the first fire, the focus is to make sure real-world crashes would not put drivers at risk. 

[via Left Lane News]