Lithium batteries have brought a huge leap forward for mankind. Smartphones, multi-rotor drones, long-distance electric vehicles, e-bikes, all-weather laptops, electric unicycles and skateboards – we all have lithium batteries to thank, but high-density lithium batteries contain enormous amounts of energy and can cause staggering damage when thermal runaway occurs. So the researchers built fire-extinguishing capabilities into the batteries themselves.
Thermal runaway and discharge are less likely to occur with lithium batteries, especially if they are manufactured to strict standards and properly maintained. But now that we have so many lithium batteries in our homes, businesses, garages, backpacks, and vehicles, and so many cheap, substandard batteries, lithium battery fires have become a fact of life. In 2022 alone, there were more than 200 lithium battery fires in New York City. You definitely don’t want to be around when a fire breaks out.
When a lithium battery with a small capacity ignites, the explosion is powerful enough to blow out the windows of the room. They can become flamethrowers that spray molten metal, ignite nearby buildings and vehicles, and are difficult to extinguish once thermal runaway occurs. But researchers at Clemson University and Hunan University say they have made a breakthrough on a solution.
The research team created a new type of rechargeable lithium battery by replacing the typical, highly flammable electrolyte liquid with something typically found in fire extinguishers. Not only that, but instead of using ordinary flammable organic solvents as the battery electrolyte, they used a modified version of 3M's Novec 7300 non-flammable thermal fluid.
"The electrolyte allows charge-carrying lithium ions to pass through the separator between the positive and negative electrodes of a lithium-ion battery," one of the researchers wrote in an article for The Conversation. "By modifying an inexpensive commercial coolant to function as a battery electrolyte, we were able to create a battery that can extinguish its own fire."
Self-extinguishing electrolytes perform well in both lithium and potassium-ion batteries and will not catch fire even if a nail penetrates the battery. Fire extinguisher solution also performs well as an electrolyte, functioning well in the -100 to 175°F (-75 to 80°C) range, handling extreme heat and cold significantly better than traditional electrolytes, and in some cases maintaining battery capacity over a greatly increased number of charge cycles.
It also appears to be easily scalable on a commercial scale. "Because our alternative electrolyte has similar physical properties to currently used electrolytes, it can be easily integrated with current battery production lines. If industry accepts it, we anticipate that companies will be able to utilize existing lithium-ion battery equipment to produce non-flammable batteries," the researchers wrote.