DOT meeting highlights numerous safety issues surrounding electric vehicle batteries

With electric vehicles becoming an increasing percentage of the U.S. fleet, new issues and challenges are emerging, including the safety of electric vehicle batteries.

On Tuesday, Aug. 27, the U.S. Department of Transportation held a virtual stakeholder meeting addressing EV battery safety. Comprised mostly of researchers, presentations revealed numerous safety issues the battery component of an electric vehicle alone pose, including the transport of lithium-ion batteries.

One common theme was the fact that EV batteries can reignite well after the initial fire. After an electric vehicle fire is put out, the battery may still maintain a charge. Consequently, it is susceptible to reigniting while the damaged vehicle is being transported or stored.

In some cases, the EV battery reignited while being towed. In other cases, the battery reignited in the tow yard days later. Victoria Hutchison, senior research project manager at the Fire Protection Research Foundation, suggested that towed electric vehicles should be at least 50 feet away from their surroundings. Some facilities storing electric vehicles that caught fire have large containers filled with water in which to submerge them to prevent any heat-related reignition.

Water itself can be the cause of EV battery fires. After Hurricane Ian in 2022, thousands of electric vehicles were submerged in water, resulting in dozens of fires. The storm also caused other lithium-ion battery fires, including golf carts and power tools.

EV batteries pose several new challenges for first-responders as well.

Average fire suppression time for an electric vehicle can be up to 90 minutes or more. Comparatively, it takes about 30 minutes to put out a fire on an internal combustion engine vehicle.

Thousands of gallons of water are needed to fight an EV battery fire, compared to about 500 gallons for gas or diesel vehicles. Water runoff from firefighting efforts is more toxic too. The pH level of water runoff from an electric vehicle fire is about 7.5 compared to 2.7 for internal combustion engines.

A proposed rule by the National Highway Traffic Safety Administration aims to establish new safety standards for EV batteries, including:

• Performance tests measuring safe operation under certain conditions, including overcharge and over-temperature
• Water exposure protection
• Require manufacturers to provide documentation showing how an electric vehicle monitors and controls battery operations
• Warnings to drivers when a thermal event occurs
• Emergency response guides for every make, model and model year

Although some claim sodium-ion batteries may be a safer solution to lithium-ion batteries, Dr. Nathan Johnson, postdoctoral appointee at Sandia National Laboratories, suggests otherwise. Dr. Johnson’s research reveals that sodium-ion batteries are just as dangerous as lithium-ion batteries. In some scenarios, sodium-ion batteries pose more safety risks.

“New technologies often claim to be safe, and there’s little to no data on them actually being safe,” Dr. Johnson said.

Transporting EV batteries

In addition to EV batteries posing safety risks to owners and first- and second-responders, there are also safety concerns among those who transport the batteries.

Considering EV batteries can unexpectedly catch fire, the federal government is taking measures to mitigate the risks associated with their transport. The main agency tasked with addressing that issue is the Pipeline and Hazardous Materials Safety Administration.

In January 2023, a new PHMSA rule regarding the air transport of EV batteries went into effect. The rule prohibits the transport of lithium-ion battery cargo on passenger planes and requires batteries to be charged at 30% or less. Batteries that are damaged, defective or recalled are strictly forbidden for air transportation.

Currently, there are no similar rules addressing ground transportation of EV batteries. However, lithium batteries are considered a Class 9 hazardous material and are subjected to applicable hazardous material regulations.

PHMSA has published a lithium battery guide for shippers that “provides generalized guidance on the requirements for proper packaging and hazard communication of shipments of” batteries by all modes of transportation.

Researchers are currently looking into a Battery Logistics Integrated Safety System (BLISS), which seeks to create EV battery packaging and storage that can mitigate the risk of fire and give carriers and first responders early detection. Essentially, BLISS is a program designing “smart” containers, including:

• Trailers
• Footlockers
• 55-gallon drums
• Fire blankets

EV battery fires prompt calls to end California’s truck emission rules

Tuesday’s DOT meeting about EV battery safety comes shortly after two lithium-ion battery fires caused significant highway disruptions.

On Aug. 19, a Tesla Semi electric truck caught fire on Interstate 80 in California. A portion of the interstate was shut down for 16 hours as emergency crews tried to contain the fire. Trucks were being held westbound at the Nevada state line. Two days after the incident, the National Transportation Safety Board announced it was opening an investigation into the crash.

A few weeks before the Tesla Semi fire, a tractor-trailer hauling six EV batteries caught fire on Interstate 15 in California. The interstate was shut down for two days, leaving motorists stranded in triple-digit heat. Detours on Interstate 40 were backed up for 50 miles.

On day after the Tesla Semi fire, a coalition of Republican state lawmakers urged Gov. Gavin Newsom to hit the pause button on the state’s Advanced Clean Fleets rule. The regulation requires that 100% of manufacturers’ sales be zero-tailpipe-emission trucks by 2036. Drayage operations, government fleets and “high priority” fleets with 50 or more vehicles must transition a certain percentage of their fleets to zero-emission trucks.

In the letter, lawmakers point out that there was minimal action first responders could take, because adding water to a lithium-ion fire would release toxic fumes. Legislatures say that in addition to disrupting travel and commerce, the I-15 incident “could have endangered lives and livelihoods.”

“If one diesel truck carrying six batteries can shut down a major highway for 48 hours, what will happen when the highways are swarming with electric trucks powered by these batteries?” the lawmakers ask the governor. LL