keep in mind intense stories for fires on electric vehicles and past disasters with overheating of lithium-ion mobile phone batteries, it is reasonable to worry that the battery of an electric vehicle (EV) will catch fire. But how often does this actually happen and why?
Do EVs ignite more often than gas cars?
Compared to how long gas cars have existed, there is not much evidence of electric vehicle fires at the time of writing. But there is enough to make some decisions. Car insuranceEZ compared data from many sources to try to find an answer to the question of how often electric cars are set on fire.
Their sources were:
- National Transport Safety Board (NTSB)
- Bureau of Transport Statistics (BTS)
Of the 100,000 vehicles sold, hybrids actually had the most fires and battery electric vehicles the least. As for the type of vehicle with the highest total number of fires, was far from gasoline cars. Reminder data show that various components can cause a gas fire in a car, but for electric cars and hybrids it is almost always the battery.
In general, the probability of ignition of electric vehicles is about .3%, while gas cars have a 1.05% probability of ignition. This should be good news for electric car owners, but as the AutoinsuranceEZ report states, car fires are dangerous for whatever reason.
EV fires are rarer but more difficult to put out
Although data show that EV fires are less common than fires in petrol cars, EV fires burn hotter and for longer periods of time. In gas cars, there is usually a reaction, like a spark in a puddle of gasoline, which causes a fire and this reaction eventually burns out. When the lithium-ion battery of an electric car ignites, the battery burns the energy stored inside, becoming the main source of energy for the fire and takes much longer to consume.
Lithium-ion traction batteries are designed to contain a huge amount of energy in a very small space. Each cell inside is filled with a flammable electrolyte, as well as electrodes that can shorten if damaged or improperly maintained, leading to overheating of the cell.
If a cell overheats, it can go through a process called thermal escape – in general, positive feedback, in which it continues to heat up very quickly – and ignites the neighboring cells in the battery until the whole thing rises. Lithium-ion batteries can also be re-ignited after they have been removed if moving them causes further damage or new short circuits in the battery.
Because first aid workers are mostly trained on how to put out fires in a gasoline car, they may have trouble putting out an EV fire because it behaves differently. Instead of cooling the part of the car that a firefighter would normally do, they should direct the water to the bottom of the vehicle where the battery is located. Stored energy left inside the battery, called destroyed energy, can cause the battery to re-ignite hours or even days after the original fire was extinguished if this energy is not treated properly.
What can cause EV ignition?
Many factors can cause a fire in an electric car, mostly related to the battery. If the battery is damaged in an accident, for example, it may cause a short circuit in one or more of the lithium-ion cells and initiate a thermal chain reaction.
If not properly maintained, the components inside the battery pack may deteriorate to the point where a malfunction can cause a fire. Defects in production can also cause car fires in both EVs and petrol vehicles.
Age can also be a factor. There is still not enough data to show whether the batteries of electric cars that are, say, 20 years old pose a greater risk of fire, but this is something you need to know as the components may deteriorate over time with heavy use and poor maintenance.
Do you have to worry about electric car fires?
The conclusion at the time of writing is that EV fires are much rarer than fires in gasoline cars. They are also much hotter, burn for longer periods and can therefore be very dangerous.
This does not necessarily mean that all EVs are more dangerous than gas vehicles, just that standardized safety guidelines need to be developed to deal with these fires if and when they occur. If you have one, make sure you take excellent care of the maintenance of the components so that the risk remains low.