An Indiana fire department responded to an electric vehicle (EV) fire in the maintenance department of a local dealership over the weekend and decided to put into action one of their training scenarios. 

“A ‘hot’ topic in the fire service right now is EV or electric car/lithium-ion battery fires,” a Facebook post by the Carmel Fire Department says. “The Carmel Fire Department has experimented with car fire blankets, firefighting foams, and other extinguishment tactics. If one of these vehicles catches fire on the roadway or in a parking lot, it is hard enough to extinguish, however, one in a garage or other structure presents a whole new set of issues.”

Firefighters were met with heavy smoke conditions and the water sprinkler system activated upon arrival to the maintenance area, the post says. 

A majority of the fire was extinguished quickly, according to the post.

“However, being lithium-ion it’s nearly impossible to fully extinguish if there is thermal runaway,” the post says. 

The post says that one of the tactics discussed during training focused on removing an EV from a structure. 

Firefighters first lowered the EV, which was on a lift, onto wheel dollies then the vehicle was pushed out of the maintenance area by manpower and a forklift. 

“This required plenty of firefighters and water to keep the fire in check,” the post says. “After loading the vehicle on a flatbed, a fire engine followed the flatbed and vehicle until it reached the salvage yard.”

A Collision Industry Conference panel discussed the importance of handling battery systems in July.

Scott Baumfalk, shop foreman at Automotive Imports and instructor at Automotive Certified Training Academy in Colorado, also gave some specifics on hybrid and EV batteries. 

The batteries have some similar hazards to 12-volt batteries, such as possible toxic gasses emitted as they heat, cool, and charge.

“They’re also highly flammable,” Baumfalk said. “Because there will be gasses internally in these enclosures, they’re vented to the outside atmosphere, and in the repair industry — collision industry in particular — where you have a lot of sparks potentially and a lot of heat, you’re going to see more gasses and you’re going to have more potential for fires or flashes or somebody getting ill from the fumes of these batteries.”

If a cell voltage cannot be balanced and a lithium-ion cell falls below 2 volts or near 2 volts, it can switch polarity and cause a runaway or thermal event, he said.

“These batteries are located all over the place in these automobiles and the Mercedes enclosure, in particular, are often mounted under the hood where they have coolant running to them and if they get damaged and they get coolant on those cells or a liquid, they will have a very serious thermal event in short order,” Baumfalk said.

The severing of a cable running to a battery receiving power could also end in a larger thermal event, he said.

He said the Mercedes system is unique in that it keeps all the components compact in a smaller, centralized area.

Baumfalk also used an example of an Audi 48-volt system using a starter motor or integrated starter generator. He said on some Audi models, the battery system sits in the lower right-hand corner and a frontal impact would likely cause damage.

“You’re going to lose coolant,” he said. “You’re going to have to replace these alternators or starter generators. These will also have to be programmed.”

In Baumfalk’s example, the Audi system had the 12-volt battery, 48-volt battery, and DC/DC converter in separate areas on the vehicle, in contrast to the Mercedes example. With a separated model, cables that are either purple or light blue will be found in different locations on a mild hybrid, he said.

The voltage won’t be present in any function where the car wouldn’t be driven such as the keys out of the vehicle or a door or hood open, he said. The separated system is more common for OEMs he said.

“I think the reason they have gone to this particular system is it was easier to integrate a mild hybrid system on an existing platform rather than redevelop an entire platform like Mercedes did with their integrated starter motor between the engine and transmission,” Baumfalk said.

OEM-specific software and a suitable charger to close the contactors is the only way to allow the 48-bolt battery to take a charge, he said.

OEM1Stop.com is an industry site, developed by automakers, that provides access to vehicle repair and service information including Emergency Service Guides for first responders, written by OEMs. The guides include proper battery removal and storage guidance and information about what should happen once the vehicle is brought inside the repair facility.

The Energy Security Agency (ESA) also staffs a 24/7 Guidance Center for first responders, towing and recovery, recyclers, salvage yards, and the repair industry to answer questions about properly handling EV and hybrid vehicles.

The center can walk through risk assessments and help each party label the vehicles with color-coded stickers that warn others of potential risks.

The National Fire Protection Association offers numerous EV training online for first responders and the general public, including training sessions for vehicle dealerships. The U.S. Department of Energy website also lists EV fire training resources.

Images

Photos are courtesy of the Carmel Fire Department.