Thermal Runaway 101

Lots of articles discuss the possibility and consequence of battery fire, but very few decide to talk about the most common characteristics precursing or following it: Thermal Runaway.

The definition of a thermal runaway is, in essence, a rapid reaction of oxidation which results in an exothermic, positive feedback loop where the heat generated from the initial reaction accelerates the rate of reaction itself, causing chain reaction of catastrophic proportion.

The essence of thermal runaway is essentially the positive feedback loop which facilitates a rapid reaction with devastating severity. As such, it is no surprise that thermal runaway is basically chemical and might occur in various chemical reactions (most notably involving exothermic and high energy reactions). However, there is something a lot closer to home, and even though the core of it is still chemical reactions, we know it as battery fire.

What really strikes me at first is the significant increase of battery fire within the last 10 years. Mass-produced, battery-powered equipment have indeed increased in number, but a lot of other factors contribute to the possibility of thermal runaway reaction.

One of which is the behaviour of the user to overcharge. The tendency of leaving the charging process overnight can induce thermal damage to the battery cell, which in turn increases the possibility of thermal runaway.

As is with thermal damage, mechanical damage could also trigger a battery fire incident, and each could potentially turn into thermal runaway reaction. This is most certainly true with the number of electric scooter fires, which due to the heavy load and user-abuse, are more prone to battery fire and thermal runaway reaction.

The composition of the battery itself plays a major part, with most battery fires are of Lithium-Ion type. 

Thus, what can we do to limit the risk of thermal runaway in our own backyard? The obvious first step is to limit the usage of lithium-ion devices. Inevitably, some devices are irreplaceable for work and communication, which lead to the second step of maintenance of the devices.

Make sure to never overcharge any lithium ion devices, and try not to impose thermal, electrical or mechanical damage to the device, and on the battery itself.

However, what can we do if a thermal runaway of the battery has already occurred? The violent nature of the reaction suggests that trained professionals should handle the situation. However, if it is safe to do so, use CO2 based PFE units to suppress the fire. Once suppressed, and if safe to do so, proceed to move the device to a secluded area far from the occupants and any combustible material. This is due to the fact that thermal runaway may occur again and reignite, causing more damage.

Written by

Fahri Ali Imran




Leave a Reply

Your email address will not be published. Required fields are marked *