Experts Warn of Electric Vehicle Fires After Hurricane Ian Damages Lithium-Ion Batteries
As millions of Americans recover from Hurricane Ian, which made landfall near Fort Myers, Florida, on September 28, officials are warning of a new hazard: electric vehicles (EVs) that were damaged in the storm and now pose a fire risk.
“Our first responders are being put in harm’s way,” Florida State Fire Marshal Jimmy Patronis said in a video posted on social media earlier this month. “Homes that may have survived the storm are now being burned down.”
According to the Florida Phoenix, firefighters in Naples have responded to at least six fires involving EVs that had been damaged in the storm. Experts say vehicles that may have been submerged in saltwater for extended periods of time are of particular concern—and with storm surge from the powerful Category 4 hurricane having reached as high as 15 feet in parts of coastal Florida, thousands of vehicles could now fall into this category.
“Electric vehicles that have been submerged in water, especially saltwater, have a potential risk of experiencing a high-voltage electrical battery fire,” said Victoria Hutchison, a project manager at the Fire Protection Research Foundation, the research affiliate of NFPA. “First responders should be prepared to respond to a potential fire and should handle EVs that may have been submerged with greater caution.”
What is thermal runaway and stranded energy?
Most electric vehicles in use today are powered by lithium-ion batteries. When damaged by something like saltwater, heat, or force, a chemical reaction known as thermal runaway can start inside the cells of these energy-dense batteries. In this state, the batteries heat up uncontrollably and can be prone to fires and off-gassing, which can also result in explosions in confined spaces.
First responders should be prepared to respond to a potential fire and should handle EVs with greater caution.
When EVs batteries are submerged in saltwater, specifically, “salt bridges can form within the battery pack and provide a path for short-circuit and self-heating,” the National Transportation Safety Board (NTSB) said in a statement sent to Patronis.
Hutchison echoed that point. “Saltwater can accelerate corrosion,” she said. “So, in a saltwater storm surge scenario, the salt deposits that can remain on the EV batteries after the water recedes can cause rapid corrosion and increase the risk of thermal runaway. Furthermore, there’s no set period in which this potential thermal reaction will occur—it can be hours, days, or even weeks later.”
Last week I witnessed an EV fire during Hurricane Ian operations. Firefighters put out the fire, then it would reignite. The teams said it was a result of salt water affecting compromised batteries, so we asked for additional information from @NHTSAgov. They responded. (1/5) pic.twitter.com/YDi7H26ykd— Jimmy Patronis (@JimmyPatronis) October 14, 2022
Compounding the risk of thermal runaway is the fact that there’s no easy way of draining the energy out of damaged batteries—a separate concept known as stranded energy. This is true even after a fire has occurred and been initially extinguished. In 2018, for instance, after a fatal crash and fire involving an electric vehicle in California, the car’s batteries reignited at a junkyard six days later.
RELATED: Read more about stranded energy and thermal runaway in an NFPA Journal feature story published in 2020
Because of these risks, Hutchison and other experts have recommended that Florida first responders and the public “remain on high alert” for fires involving damaged EVs in the wake of Ian.
If you own an EV that may have been damaged during Hurricane Ian, “please get it towed away from your home but … make sure the towing operator knows how to safely and properly tow EV vehicles,” the North Collier Fire Control and Rescue District Administration wrote in a Facebook post.
In statements released publicly last week and also sent directly to EV manufacturers and federal officials, Florida Senator Rick Scott urged action from manufacturers to provide more fire safety guidance for both consumers and the fire service.
“The current guidelines from EV manufacturers on the impacts of saltwater submersion on the operability of the vehicles do not adequately address the issue,” Scott wrote. “As a result, most consumers are under the potentially life-threatening misimpression that their EVs will continue functioning properly after saltwater submersion.”
NFPA already offers guidance for the fire service on how to best respond to incidents involving electric vehicles. As EVs have grown in popularity over the past several years, NFPA has helped educate more than 300,000 first responders on this emerging hazard. Visit nfpa.org/ev to learn more about the EV responder training opportunities from NFPA.
Top photograph: Ivan Radic via Flickr