Flameproof car batteries: Just add salt?
Our lives are tied more and more tightly to battery-powered objects. When we think about improving these devices, efficiency tends to be our chief concern, but safety improvements are finally catching up, thanks to a very familiar chemical compound: Salt.
Batteries are all about chemistry, so first we need to mention how conventional, lithium-ion (Li-ion, for short) batteries work.
Inside the battery case are plates. The spaces in between are flooded with an electrolyte made of a lithium salt dissolved in a liquid organic solvent, such as ether or carbonate. Both ether and carbonate are flammable; should the battery case rupture or become punctured, you could easily have a serious fire on your hands (or, if you’re riding a motorcycle, under your butt).
We have known for some time that Li-ion batteries are vulnerable to fire. Thanks to a U.S. Department of Energy Lab operated by Stanford University, which boasts no fewer than three Nobel Prizes in Physics, we may have a practical way to flameproof them.
SLAC (originally named Stanford Linear Accelerator Center) National Accelerator Lab in Menlo Park, California, has developed a new electrolyte with higher salinity that significantly lowers a Li-ion battery’s flammability. Naturally, the lab dubbed it SAFE, an acronym for Solvent-Anchored non-Flammable Electrolyte.
To be fair, SAFE is not the first non-flammable electrolyte available to battery producers. This is just the first that is viable. Previous concoctions required re-tooling the design of the battery, a process that, for most manufacturers, would be wildly costly and impractical. This new SAFE formula congeals into a gooey substance that can work its way in-between the battery plates of the current case configurations. Per SLAC, switching to the SAFE electrolyte requires no changes to the current manufacturing process at all.
Another big plus to using this salt-heavy cocktail: The batteries can safely operate at a slightly higher temperature without worrying about thermal runaway or the case bulging and bursting into flames as the cell temperatures rise. With less need for cooling, the same-sized battery pack can now pack more energy. In the automotive world, that could mean cars with longer range but no added weight.
While cars have been the latest high-profile instance of lithium-ion batteries posing a fire risk, you don’t have to go far into the past to find smaller handheld electronics overheating and exploding in balls of fire. SLAC’s new electrolyte can be used far beyond the transportation sector, so it will likely make so many devices that we interact with daily a little safer.
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