St. Petersburg Fire Rescue responded to at least two electrical fires during hurricane Helene, one of which involved an electric vehicle. Images: St. Petersburg Fire Rescue

Helene and Milton reveal an emerging challenge for first responders: EV batteries catching fire

When a hurricane like Helene or Milton ravages coastal communities, already strained first responders face a novel, and growing, threat: The lithium-ion batteries that power electric vehicles, e-bikes, and countless gadgets. When exposed to the salty water of a storm surge, they are at risk of bursting into flames — and taking an entire house with it.

By Tik Root

The battery in an EV is comprised of thousands of cells stacked and packed into a sealed enclosure. If salt water, which is particularly conductive, reaches the interior of a battery, it can cause a short-circuit, which can generate excessive heat that jumps from cell to cell. “That’s called thermal runaway,” said Andrew Klock, senior manager education & development at the National Fire Protection Association. As a battery heats up, it releases flammable gasses that can ignite.

How does exposure to salt water affect an EV battery?

According to the Department of Transportation, “the time frame in which a damaged battery can ignite varies, from days to weeks,” so the danger doesn’t end when a storm passes. This is one reason Tesla urges owners not to operate a potentially compromised vehicle until a dealer inspects it.

How long does the battery take to ignite after being exposed to salt water?

Once the car starts burning, methods of putting out traditional vehicle fires — such as foam or thermal blankets to smother the flames — aren’t as effective. “Lithium-ion batteries generate their own oxygen and heat when they are on fire,” Klock said. “You can’t starve the fire.” First responders must direct high volumes of water as directly at the battery pack as possible in order to reduce the heat.

How is the fire extinguished?

There have been 48 confirmed battery fires related to storm surge from Hurricane Helene, 11 of them associated with EVs. Overall, such fires are far from common. Idaho National Laboratory found that, of the 3,000 to 5,000 electric vehicles damaged by Hurricane Ian in 2022, about three dozen caught fire.

How often do fires happen?

The Federal Emergency Management Agency has funded research into emerging hazards of at-home battery storage systems. Other researchers are looking at how to make batteries safer, including Dr. Yang Yang, an associate professor of material science and engineering at the University of Central Florida. His team developed a battery that, instead of fighting salt water, utilizes it as the main electrolyte.

Is anything being done about this?

Helene and Milton reveal an emerging challenge for first responders: EV batteries catching fire

“They burn hot, they burn fast, and they’re hard to extinguish.”

By Tik Root

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All images: St. Petersburg Fire Rescue