EV Fires Can Reignite Hours After The Flames Are Gone

Firefighters know exactly what they’re up against with an internal combustion vehicle fire. Kill the flames and cool the metal so what remains of the vehicle can be towed away. With an EV, though, the fire can come back hours after the fire is seemingly suppressed. When a lithium-ion battery pack enters thermal runaway, a self-sustaining chemical reaction, cells continue to overheat from the inside and vent (accompanied by a popping sound) long after the fire appears to be out. This reaction creates toxic gases that feed the heat and can reignite at any time with no warning. That one difference is the main factor that makes fighting electric vehicle fires so difficult to suppress and safe to leave.

While water is still the most commonly used method for suppressing these fires, the volume of water used is quite considerable. One Tesla battery fire documented by the International Association of Fire and Rescue Services needed roughly 24,000 gallons over 40 minutes to bring under control. Some estimates suggest EV fires can demand up to 40 times more water than a conventional ICE vehicle blaze to put out.