With the rapid development of motoring and related technologies, electric cars are gaining popularity. Electric vehicles represent a step towards protecting our planet, as well as reducing refuelling costs. However, as the technology has developed, many myths have arisen around it. Do electric car fires occur more frequently than combustion cars? Is a battery located under the floor of an electric car a ticking bomb?
In this article, we take a closer look at the problem of fires in electric cars, looking at causes, statistics, extinguishing methods and their prevention.
Causes of electric car fires
Fires in electric cars are a topic of great interest and need to be analysed in detail. There are several main causes that can lead to an electric vehicle catching fire:
- Short-circuit of the internal battery cell. The battery in an electric car consists of many individual cells. An internal short circuit in any of these cells can ignite or cause a vehicle fire.
- External short circuit. An external short circuit can also occur when the entire battery is connected to the power electronics, motor and other components.
- Charge and discharge cycles. During charge and discharge cycles, the current flowing through the battery can generate heat, which raises the temperature of the cells and the entire battery. If this process is not properly regulated, it can lead to uncontrolled temperature increases.
- High operating temperatures. In addition to the natural heat generation of the battery, operation at higher temperatures (typical in some regions such as India) further affects the battery temperature. If the battery is unable to adequately dissipate the heat generated, the risk of ignition increases significantly.
- During an accident, the battery can be damaged, which can lead to a fire.
It should be noted that electric car manufacturers are undertaking intensive research and innovation to minimise the risk of fires. Developments in technology and rigorous safety testing aim to ensure that electric vehicles are as safe as their combustion engine counterparts. BEV batteries are equipped with a comprehensive fire safety system. It is constantly active: both when the car is parked and while driving and charging. The safety system includes, among other things, a cooling system to prevent the battery from overheating and a reinforced protective housing to prevent mechanical damage. A firewall, which separates the battery modules, limits potential damage and protects other vehicle components from ignition. The risk of fire is also minimised by a high-voltage emergency shutdown system and a circuit that separates the battery voltage from the rest of the vehicle’s electrical system when stationary.
User awareness of proper battery use and maintenance is also a key aspect in preventing fire incidents.
Electric car fire statistics
According to the National Fire Service, the number of electric vehicle fires was relatively low compared to internal combustion vehicles.
In 2022, only 10 incidents of electric car fires were reported. In comparison, only 4 such incidents were recorded in 2021. Of course, it is worth remembering that the number of electric vehicles on the road is still lower than that of combustion vehicles.
In Poland, where we have around 30,000 pure electric vehicles (BEVs) and as many as 20 million combustion vehicles, looking at fires in the context of 100 vehicles, the probability of a fire for electric cars is only 0.03, while for traditional combustion vehicles it is 0.04.
Ways to extinguish electric car fires
Extinguishing electric car fires is a task that firefighters can perform effectively. Electric vehicle fires are a new and fairly rare phenomenon, but one that has been widely reported in the media. It is worth noting that firefighting procedures are well developed and firefighters have clear instructions on how to deal with these new challenges.
When extinguishing electric cars, firefighters use the usual firefighting equipment and water. The extinguishing itself is no different from extinguishing a combustion car. However, it is important that they are properly prepared, protected and keep a proper distance from the vehicle.
Manufacturers of electric cars have taken care of the safety of firefighting teams by placing clear markings in their products where the electrical voltage, which in electric cars can reach up to 400V, can be cut off. With such facilities, simply pulling out the high-voltage emergency switch is enough to cut the power to the cells. One manufacturer has even developed a special entrance for the fire extinguishing hose into the battery compartment, making it possible to flood the cells and secure the situation.
During an extinguishing operation of electric cars, much more water is used compared to combustion vehicles. The cooling process for batteries and electrical components is quite long. In the case of combustion cars, 1-2 cubic metres of water are usually used, while in electric cars this amount can reach up to several cubic metres, depending on the duration of the extinguishing action.
After the action, firefighters also use thermal imaging cameras or pyrometers to observe the car and ensure that its components do not heat up. Such observation, according to procedures, can last up to 24 hours.
Preventing fires in electric cars
There are several ways to prevent fires in electric cars. Some of the most effective ways to prevent fires include:
- Minimising exposure to heat. During the summer, the vehicle can be exposed to very high temperatures above 45°C, which can lead to a sudden rise in temperature and a so-called ‘thermal runaway’ (thermal runaway). It is recommended to avoid parking the vehicle in direct sunlight and leaving it in a hot environment. When the vehicle is not in use, it should be parked in a cool and dry place such as a garage. It is also important to keep the battery in dry areas with adequate ventilation. Battery cooling systems can also help.
- Monitor battery signs. Take care not to overheat the battery when charging. It is best to avoid charging batteries to 100%. On the other hand, lithium-ion batteries are also prone to damage if they are completely discharged before being recharged. It is recommended to charge the battery between 20 and 80% of capacity.
- Avoiding driving over sharp objects. This is just as important for electric vehicles as it is for traditional cars with internal combustion engines. For electric vehicles, sharp stones or other impacts can damage the battery. In the event of any damage, the electric vehicle should be taken to a service centre immediately so that the battery can be checked and repaired if necessary.
- Using a charging station. The use of level 2 chargers (so-called charging stations) is recommended, as level 1 chargers (standard wall sockets) require longer charging times for the vehicle and can generate heat.
- Waiting before charging. It is not safe to charge an electric vehicle’s battery as soon as it has stopped, as the lithium-ion cells inside the battery remain very hot. It is a good idea to wait until the system has cooled down before connecting the vehicle for charging.
- Use original batteries and chargers. Replacement batteries and chargers should be original products from the vehicle manufacturer or from an authorised dealer.
In summary, fires in electric cars are rare and the likelihood of incidents does not exceed that of traditional internal combustion vehicles. There are many causes of electric car fires, including short circuits, accidents and misuse. Manufacturers are actively introducing innovations and safety systems to minimise the risk of fires. It is also important that users follow manufacturers’ recommendations and ensure proper maintenance and safe use of electric vehicles.