Battery fires are rare, but when they happen, they require enormous amounts of firefighting resources. The problem is caused by the flammable electrolyte, which can generate its own oxygen in a thermal runaway reaction. Scientists at Clemson University think their self-extinguishing electrolyte can make battery fires a thing of the past.
Battery-electric vehicles are our best bet in fighting climate change and reducing pollution in big cities. Modern EVs use
lithium-ion batteries, which offer the highest energy density and a relatively long lifecycle. However, most Li-ion battery cells can be dangerous when they overheat, requiring complex thermal management systems. Because they use highly flammable electrolytes, they can burst into flames if the heat is not kept in check.This is called thermal runaway, although, from the outside, it looks more like an explosion or a rocket firing its engines. Because
EV batteries are made of thousands of individual cells, the process affects adjacent cells unless it’s stopped. To make matters worse, the blazing cells generate
their own oxygen, making the fire very difficult to put out. The reaction continues as long as the temperature is high enough or the electrolyte depletes. This is why firefighters dealing with an EV battery fire focus on cooling the battery pack.
Researchers at Clemson University in South Carolina thought that inventing an electrolyte that doesn’t catch fire is the simplest way to prevent battery fires. One that can put out its own fire is even better. So, instead of a common electrolyte, usually composed of a lithium salt and an organic solvent, they developed one based on materials found in a commercial fire extinguisher.
The revolutionary electrolyte works across a wide temperature range from about minus 100 to 175 degrees Fahrenheit (minus 75 to 80 degrees Celsius). During the nail penetration test, the batteries produced in the lab with this flame-retardant electrolyte extinguished internal fires effectively. Moreover, the electrolyte is compatible with other chemistries besides Li-ion, including potassium-ion, sodium-ion, aluminum-ion, and zinc-ion.
