Valley fire department prepared for electric vehicle battery fires

Mar. 12—DANVILLE — As the number of electric vehicles driven in central Pennsylvania continues to rise, local fire departments are preparing for the risks that come with them, including extremely hot, difficult-to-extinguish fires.

Most electric vehicles run on lithium-ion batteries which are the root of the problem when it comes to electric car fires, according to Bucknell Professor Nate Siegel, mechanical engineering, Heinemann Family professor in engineering.

Lithium batteries contain an electrolyte that is flammable, Siegel said.

"The other issue that comes into play is when they get hot, the batteries have materials that decompose to produce oxygen which essentially feeds the fire, if it ignites," he said. "It feeds itself the oxygen it needs to continue burning."

Many extinguishing methods typically involve starving a fire of oxygen which becomes very difficult, if not impossible, when the fire is feeding itself, the professor said.

This sort of reaction can be the result of a collision. "In a collision, the internal structure of the battery is damaged, which can cause a lot of heat to be generated in a small space," Siegel said.

The lithium batteries enter into a phenomenon called thermal runaway, during which their status escalates into an uncontrollable state where they continuously heat themselves, Siegel said.

Though these fires can still be extinguished with water, Siegel said it takes significantly more than would be used on a typical vehicle fire.

"One of the biggest dangers with fires of this type are the temperatures they can achieve. It's like having a blast furnace," he said. "And with a hotter fire, you run the risk of catching other things on fire that are in close proximity."

These fires' intensity and spreadability are what the Danville Fire Department is preparing to tackle. The department recently purchased four blankets at $1,500 each to be ready should this sort of emergency occur locally, according to Fire Chief John Buckenberger.

"You can't wait until you have a fire like this and think 'oh, I wish I had one of those blankets,'" the chief said. "I've prepared my department for the future."

Buckenberger said he knows there are electric vehicles driven in the Danville area, and though there has not been an emergency yet, he believes it's only a matter of time.

"We haven't had problems yet. However, some cities have had problems with them and they require 10,000 to 20,000 gallons of water to try to put out," Buckenberger said. "There have been videos of Teslas in water burning."

The chief explained why the batteries are so dangerous.

"These lithium batteries have thousands of cells of lithium enclosed in an air-tight, waterproof box. Then it's wrapped in an insulation type of material to protect them," he said. "The problem is, they get hot and catch on fire and you can't extinguish them."

Buckenberger laid out the Danville department's plan of attack. The fire crew would tame the flame enough to get the blanket over the vehicle which would contain the fire, he said.

"We want to be able to throw a blanket over a car in a garage and protect that house from burning down," the chief said.

According to Siegel, this is the tactic most fire departments would use in this sort of emergency.

"The intensity is an issue and being able to at least put materials on the fire to prevent it from spreading, seems to be what a lot of fire departments are focusing on," he said. "A blanket contains it to keep it from spreading to other areas."

Buckenberger explained fire personnel would not remove the blanket until much later.

"We leave the blanket on and eventually the fire will go out. The tow truck will come and take it and we will follow them to wherever they're going," the chief said. "We will remove the blanket several hours later."

Right now, there is no way to extinguish these fires and the issue is not with cars alone, according to Buckenberger.

"Electric bikes are also lithium batteries and people take them into their houses and plug them in," he said. "There was a fire recently where a bike was plugged in and started a fire."

Siegel said this is an active area of research and there are two issues at play, the first being the flammable electrolytes inside batteries. Developers are looking to replace it with a material that is less flammable or not flammable, Siegel said.

The other area of concern is the issue of internal short circuits in the batteries which can be caused by lithium dendrite formations that can connect both sides of the battery. To prevent this, engineers want to put a solid separator inside the battery, Siegel said.

"They have solutions they're looking at that would solve two of these issues that make the fires start in the first place," he said.

As for preparing for this sort of emergency, Buckenberger said it cost $6,000 of his budget, but it was a necessary expense.

Siegel said he thought the Danville department was responding in the right way. He does not anticipate this being an issue fire departments have to deal with for long.

"In ten years, I think this will be a lot less of an issue," he said. "Everyone knows this is a problem and they're trying to solve it and not just push it onto the fire departments."