Gary’s Q&A

Listener question & Gary’s response · Transcript passage

The first question comes from Patricia Kemmer, who asks,“Why do lithium-ion batteries catch fire? Love your podcast.”First, lithium-ion batteries catching fire is rare, but it can happen. It is due to something known as thermal runaway.

It starts when there is some sort of damage to the battery. This could be physical damage, such as a cut in the outer skin of the battery. It could also come up with a manufacturing defect or an internal short circuit.

These defects can cause a localized temperature increase where the damage occurs. The temperature increase can cause defects to occur in adjacent parts of the batter, which can then cause more defects, more temperature increases, and so on. This is how it becomes a runaway effect. This can be made worse if as the temperatures increase, the gasses which are produced are trapped inside the enclosed battery increasing pressure.

This is one of the many reasons why researchers are trying to develop solid-state batteries that don’t have a liquid or gel electrolyte. In addition to having higher energy density, they would also be much safer.

This is also why you should never use a damaged lithium-ion battery.

Again, this is a pretty rare phenomenon and, for the most part, easy to avoid.