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Scientists Developed a Self-Extinguishing Electrolyte That Can Prevent Battery Fires

Scientists developed a self-extinguishing electrolyte that can prevent battery fires 7 photos
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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.

While nonflammable electrolytes are not new, most of them contain fluorine and phosphorus, which are expensive and can have harmful effects on the environment. Instead of using them, the team at Clemson University focused on adapting affordable commercial coolants that were already widely used in fire extinguishers. The purpose was to make them function as battery electrolytes.

The best candidate proved a safe and affordable commercial fluid produced by 3M called Novec 7300, which has low toxicity, is nonflammable and does not contribute to global warming. The team combined this fluid with other chemicals for added durability. The result was an electrolyte that would enable a battery to charge and discharge over a full year without losing significant capacity.

The best part is that this electrolyte has similar physical properties to currently used electrolytes. This makes it easy to be used on current battery production lines. The researchers are confident that companies will soon be able to manufacture nonflammable batteries using their existing lithium-ion battery facilities. This will make battery fires a thing of the past, ending one of the most widespread FUDs about electric vehicles.
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About the author: Cristian Agatie
Cristian Agatie profile photo

After his childhood dream of becoming a "tractor operator" didn't pan out, Cristian turned to journalism, first in print and later moving to online media. His top interests are electric vehicles and new energy solutions.
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