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Engineer Matt Gwin puts a piece of aerogel material inside a metal frame and ignites it. After a minute or two, the material is intact and only feels warm.  Photo by Aspen Aerogels
11 Dec 2024

New gel shows promise as an insulating agent against lithium battery fires

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Electric (EVs) are becoming increasingly popular globally, but they carry risks, particularly related to lithium-ion cells that can catch fire. A new gel could be a way to stop fires in lithium battery packs to spread. 

This is a summary of a longer article on NPR.org. 

 

Read the full version of this story on NPR.org

 

John Williams, VP of Technical Services at Aspen Aerogels, notes, "Inside each of these vehicles are hundreds, if not thousands of lithium ion cells — one of the densest ways that we know to store electrical energy in a battery, but they come with tradeoffs." 

The US Department of Energy recently provided Aspen Aerogels with a $670.6 million loan to develop technology aimed at containing EV fires.

When an EV battery heats up, it can experience thermal runaway. Williams explains:

"In the case of some kind of defect, under the right kinds of circumstances, the temperature goes up and up and up until eventually the battery catches on fire." 

Although a lithium-ion battery ignites less frequently than an internal combustion engine, it burns hotter and is more difficult to extinguish. The goal is to provide passengers enough time to exit the vehicle in case of fire.

Aerogel is reportedly a promising solution. Williams describes it as "the world's best thermal insulation," likening it to "a very light, yet firm piece of gelatin." 

George Gould, Aspen Aerogels' Chief Technology Officer, characterizes it as "a very ethereal material," highlighting its 99% air composition with a porous structure. Chemist Irene Melnikova explains the manufacturing process, transforming liquids into a solid that can withstand high temperatures.

Engineer Matt Gwin demonstrated aerogel's resilience by exposing it to a propane flame of 2000 degrees Fahrenheit without damage. 

"The secret of our material is that it's passing the energy on very slowly," Gould states. Even after the flame is extinguished, the material remains intact, feeling only warm.

While aerogels do not prevent fires, they act as a "firewall." Gould adds that the technology extends beyond EVs, being useful for various industries, including oil and gas. 

Amar Pradhan from Mobility Impact Partners emphasizes the need for various safety measures, noting:  

"There's different ways to stop the fire depending on the timeline of battery fires." 

He suggests that multiple interventions will be essential to enhance the safety and efficiency of EVs.

Photo Credit: Aspel Aerogels

Engineer Matt Gwin puts a piece of aerogel material inside a metal frame and ignites it. After a minute or two, the material is intact and only feels warm to the touch.