An article entitled “Stranded Energy“, published in the National Fire Prevention Association’s (NFPA) Journal in January 2020, deals extensively with the dangers of accidents involving electric vehicles (EV), and the associated dangers of the powerful lithium-ion battery that powers the vehicle.
Firefighters were called to an accident involving a Tesla on the 101 freeway in Mountain View, CA.
While traveling at 70 mph, the vehicle suddenly swerved to the left and into the median, tearing the front end off the vehicle’s frame, ripping open the Tesla’s 1,200-pound, 400-volt lithium-ion battery and scattering energized cells across the road.
Bystanders risked their lives to pull the 38-year-old driver from the wreck before it burst into flames. He later died at the hospital from his injuries.
The badly damaged battery was shooting flames five feet into the air.
Firefighters shot copious amounts of water directly at the flaming battery and extinguished the fire in a couple of minutes. After eight more minutes with no reoccurrence of fire, they turned off their hoses.
But the severed battery continued to hiss and pop.
According to the article, fully charged, the battery has a capacity of 75 kWh—roughly enough energy to power the average US home for more than two-and-a-half days, and more than enough to instantly kill anyone exposed to it.
If punctured, breached, or otherwise damaged, heat can build rapidly inside the compromised battery cells and spread to surrounding cells in a cascade-like process called thermal runaway, which can lead to fire, arc flashing, off-gassing, and sometimes explosions.
The crash—and dozens of others like it around the world—lay bare the gaps in our understanding of what can occur in such incidents, and how far responders have to go to prepare for the rapid influx of battery technology that experts say is fast approaching.
Because of lithium ion’s penchant for reigniting without warning, NFPA recommends that an EV with a damaged battery be stored at least 50 feet away from other vehicles and buildings.
With the expected surge in the number of EVs on the road (around 130-million by 2030), ” electric vehicles and energy storage are just the next thing in a never-ending cycle for the fire service—technical advancement breeds new challenges, which are eventually dealt with and overcome.”
Since 2012, NFPA has offered online alternative fuel vehicles safety training for first and second emergency responders, which covers best practices, tools, and information required to safely handle these incidents.
According to NFPA estimates, roughly 250,000 of the 1.1 million firefighters in the US have received the training, which is periodically updated as more information is gathered.