Electric cars

Why do electric vehicles catch fire? How to prevent EV battery fire?

Ola Electric has made headlines as its electric scooter caught fire in Pune. (HT_PRINT)

The risk of fire in electric vehicles is significantly lower than in ICE vehicles, but they are difficult to extinguish.

By : HT automatic office
Written by : Mainak Das
March 28, 2022, 11:42

Ola Electric made headlines when its electric scooter caught fire in Pune. (HT_PRINT)

Over the past few months, there have been several reported incidents of electric vehicles, especially electric scooters, catching fire. In one of the tragic incidents, a father and daughter duo died in Tamil Nadu when their electric scooter caught fire inside their home, suffocating them. Apart from that, several fires involving Okinawan and Ola Electric scooters made their appearance. There is a question linked to all these incidents: why do the batteries of electric vehicles catch fire? Then, how to avoid an EV battery fire?

(Also read: Ola Electric launches probe after video of S1 Pro on fire in Pune goes viral)

Here’s a comprehensive look at why lithium-ion electric vehicles catch fire and how to avoid an EV battery fire.

Why do EV batteries catch fire?

Lithium-ion batteries mainly fail for two different reasons. The first is a defect in the manufacture of the battery itself. The second type of battery failure is usually the result of several factors – stress on the battery like vibrations, a short circuit, or just a fluke. A manufacturing defect in a battery can cause a fire. On the other hand, too much vibration, far beyond the handling capacity of the lithium-ion battery, can lead to a fire hazard. In addition, an electrical short circuit can cause a fire.

Lithium-ion and lithium-metal cells experience thermal runaway when they fail. Thermal runaway causes battery cell temperature and pressure to rise rapidly, as well as the release of flammable gases. These flammable gases often result in a flame eruption ignited by the high temperature of the battery, which eventually leads to a fire.

Apart from this, thermal runaway can also be caused by microscopic metal particles coming into contact with different parts of the battery resulting in a short circuit. In the event of a slight short circuit, the battery faces high self-discharge and little heat is generated because the discharge energy is very low. But, when a substantial amount of microscopic metal particles converge at one point, it can result in a major electrical short causing a large flow of electricity between the positive and negative plates, which can lead to combustion. In such a case, the temperature inside the battery case can quickly reach even 500 degrees Celsius, which can lead to the cells exploding or burning.

Warning Signs of an EV Battery Fire

There are certain types of signs one can feel, in case a lithium-ion battery is about to catch fire. The battery may feel extremely hot or swell. Additionally, the battery may begin to discolor, causing damage, blistering, and beginning to emit smoke.

How to avoid EV fire?

Electric vehicle fires are rare, and the risk of fire in electric vehicles is significantly lower than in internal combustion engine vehicles. However, when an electric vehicle with a lithium-ion battery is on fire, it is really difficult to fight. Although there are some basic tips you can follow in order to minimize the risk of fire.

The EV battery should not be charged immediately after the EV is turned off, as the lithium-ion cells inside the battery remain very hot at this time. Instead, let the battery cool down and then charge it. If it is a removable battery, it is best to disconnect it from the vehicle and charge it separately.

Use only the battery designed for the vehicle. Using a cheaper local battery can also damage the electric vehicle. Also use the charging cable supplied with the mobility device.

Avoid placing batteries in direct sunlight or in hot vehicles. Store batteries in dry areas with adequate ventilation, if removable. Remove batteries from their charger when fully charged. Replacement batteries and chargers must match and be from the original manufacturer or an authorized dealer.

Inspect for damage and batteries before use. If there is a defect, do not use it and report it to the manufacturer. Avoid using the battery if it is extremely hot and has any damage.

Date of first publication: March 28, 2022, 11:41 a.m. IST