Only You Can Prevent Phone Fires

By Bill Hughes

The Galaxy S8 uses lithium-ion (Li-ion) batteries. As the name implies, these batteries are based upon the element lithium (Li). Lithium works really well for cellphone batteries because it’s very light.

The problem is that if lithium gets too hot, it burns. Lithium can catch fire at a relatively modest 180ºF, and then burn like crazy at 1,100ºF. By comparison, dry firewood won’t ignite until 451ºF, and will then burn at 1,100ºF. In other words, lithium burns just as hot as a campfire, but it ignites at a much lower temperature.

To make things safe, battery makers and cellphone manufacturers implement all kinds of sneaky and imaginative methods of removing the heat from around the lithium battery. In addition, your phone invisibly monitors temperatures and takes steps to ensure that it doesn’t get too hot. This all works so well and seamlessly that you probably didn’t even notice this was happening in your earlier phones and other gizmos that use Li-ion technology.

So, here’s the big problem: If things start going wrong with Lithium-ion batteries, many of the sneaky and imaginative methods used to remove the heat begin to fail. The fancy term for what happens next is thermal runaway. When thermal runaway happens in a device with a Li-ion battery, one of two things happens:

  • The guts of the phone will bubble and melt.
  • The battery will burst into flames, throwing sparks for several feet in all directions.

So, what should you do and, perhaps more important, what should you not do? If your phone has started to burn, the best possible solution is to dunk it in a glass, bucket, or toilet full of water. If you can’t find something to dunk it in, you can throw water on the phone to stop the fire. Water both cools the lithium and prevents oxygen from getting to the flame. Getting your phone wet goes against all your instincts, but once a phone has started bubbling, all your texts and photos have already been lost. Prevent further damage and use water to put out the fire.

If you don’t have water handy, and you’re somewhere outside, in a parking lot or on a sidewalk away from people, you can set the phone on the ground, get far away from it, and call 911. Stand far back from the phone. It could explode. For obvious reasons, putting out the fire by dunking the phone in water or dousing it with water is best.

Smothering the phone with a blanket or dirt won’t work. Even if you get the fire stopped momentarily with these methods, the battery is likely to start burning again because it’s still too hot. A fire extinguisher with anything other than water or a liquid will also not work well. As with a blanket or dirt, the battery stays hot, and when oxygen reaches it, the lithium will simply reignite.

You might think that if water is good at cooling off a Li-ion fire, a pile of ice would be better. Unfortunately, you would be wrong. Check out this video from the Federal Aviation Administration that shows some battery fires. It shows that a huge pile of ice, which would do wonders to stop a campfire, cools the battery too slowly, and the darn things burns anyway. Go figure.