Hybrid vehicles have a 3,5% risk of causing a fire, compared to 1,5% for gasoline and 0,025% for electric vehicles
During Easter weekend, the first case of a Jeep 4xe fire was reported
Battery fires are relatively rare, but they are more difficult to deal with
Since they have been introduced, electric cars have been regarded as prone to catching fire by the general public but it turns out they are the least likely type of vehicle to burn down.
Indeed, battery electric vehicles (BEV) have only a 0,025% risk of catching fire in normal operation, which is lower than gasoline powered vehicles and much lower than hybrids.
Despite a large number of electric vehicles having been recalled in the last few years, the actual cases where one caught fire due to a manufacturing defect are relatively rare.
For example, General Motors recalled all 140,000 units of the Chevrolet Bolt because their batteries could be defective, but less than 20 fires in Canada and the United States have been linked to this problem.
In fact, hybrid vehicles are much more likely to catch fire at some point in their useful life, since their risk is evaluated at 3.5%.
The presence of a gasoline engine next to a high-powered electric system and a battery is apparently the cause of most problems since there is a lot of heat generated under hood in hybrids.
Fires caused by batteries usually happen while the vehicle is charging, but it can also occur while driving. This is what happened to a Quebec family over Easter this year, when their Jeep Wrangler 4xe caught fire just after exiting the Georges-Washington bridge in New-York. This is the first time a hybrid Jeep vehicle is the subject of a fire.
According to firefighters, the problem with electric or hybrid vehicle fires is not so much their quantity but rather their intensity. Lithium-ion batteries, which are found in most electrified vehicles, are very difficult to extinguish.
This is because the chemistry used in these batteries is prone to a thermal runaway, which happens when a damaged battery gets hot enough to self-ignite. The temperatures resulting from these types of blazes are often high enough to melt the asphalt under the vehicle and break the windows of surrounding buildings.
Controlling these fires is also difficult, since firefighters often have to empty two or three tanker trucks before the battery has cooled down enough to be put out. To add another level of complexity, lithium batteries have a tendency to reignite on their own several hours after the fire appears to have been extinguished.
This is what prompted some European countries to invest in special tanker trucks that can submerge an electric vehicle underwater until all risk has been eliminated.
Even if hybrid and electric vehicle fires are a serious issue, there is no need to panic since these events are rare and as the entire automotive industry is moving towards electric vehicles, battery technology will become safer in the next few years, most notably when solid state batteries replace lithium-ion ones.