A car on fire isn’t exactly novel, but an electric vehicle in flames attracts a lot more attention than an ICE car on fire and it is understandable. These days EVs are in the news almost every day, and fire is a must topic in each EV news.
What makes EV fires even more peculiar is that these fires occur when they are in use, or even while charging and that once started, they are quite theatrical, with towering flames and plumes of smoke also being hard to extinguish.
In this article, we will be dealing with certain concerns and solutions regarding EV fires.
First, we shall try to address what are all the standard operating procedures for an EV fire.
Fighting The EV Fire
With the incidents involving the Ola and Pure EV EPluto 7G scooters, as well as the tragic loss of lives in Vellore when another electric scooter caught fire, the central government has assigned a team to investigate the incidents and submit a report, as well as develop a strategy and SOPs for dealing with EV fires.
Local firefighting teams along with international bodies are researching and developing new fighting methods to seize EV fires. According to sources at the Mumbai Fire Brigade, the cooldown and observation period for electric vehicles has been doubled from 48 to 72 hours. They’ve also discovered that a huge quantity of water is necessary to put out an EV fire, so they’ll be prepared with a larger fleet of water tenders.
While EV firefighting SOPs are being developed all around the world, there is yet to be a global standard established. The use of massive amounts of water, primarily to cool the batteries, or simply let the fire burn itself out is common in all procedures.
A common method of extinguishing a fire is to block oxygen to suffocate the flame but this method is ineffective since it is a chemical fire that does not require oxygen.
Another critical step is to check the surrounding area for any battery cells that may have been pushed from the battery pack by an explosion and may have the potential to ignite later. The burnt-out EV must be removed and put in a compound away from buildings and other cars after containment. (Spent lithium-ion batteries are responsible for 25% of scrapyard fires in the United Kingdom.) Immersing the car in the water, but not seawater is a more drastic move since chlorine gas can be emitted.
The fire department in Copenhagen, Denmark, has devised a truck-mounted vehicle containment solution for electric automobiles that are on fire or at risk of catching fire. The smouldering electric vehicle is lowered into the container, which is then placed onto a flatbed truck like a skip. Water may be pumped into the container using nozzles on the bottom and sides. Once the container and automobile are full, they are transported to a secure storage location and left there for weeks, maybe months, until the vehicle is no longer a threat. If all goes properly, the water is filtered and disinfected before being disposed of safely.
The Science Behind EV Fire
There are scientific explanations for why EV fires are difficult to extinguish. The issue is that even when cells are empty, they still have a little amount of charge, and the numerous cells that make up a battery may store a lot of energy. Whether the cells are ‘full’ or ’empty,’ the possibility of this energy escaping uncontrollably is what causes ‘thermal runaway,’ which occurs when heat and gases feed at increasingly higher temperatures and even more gases, including hydrogen and oxygen, in a self-fulfilling loop until the cells burn and explode. Once the hazardous vapour cloud is formed, it poses the threat of a conflagration. No battery management system or circuit breaker can stop thermal runaway once it has started.
“You can regulate a battery fire, but you can’t put it out,” argues Paul Christensen, a professor of pure and applied electrochemistry at Newcastle University, in an interview with Autocar UK. The collision and following fire that overtook the Rimac Concept One car driven by the Grand Tour’s Richard Hammond, whose large battery burned for five days, is perhaps the most famous case.
While battery packs commonly catch fire due to overheating or charging, they can also spontaneously combust in rare cases, with contamination of even a single cell during production being a likely cause. “Even the most diligent and experienced manufacturers have faulty cells get past their quality control systems,” Christensen adds.
Another issue is that rescuing a group of EVs that has gone up in flames is a difficult undertaking. As Christensen points out, “in the last six or so months, three bus depots in Germany have gone up in flames.” He also stated that “All sites where electric cars are found, including tunnels, ferries, car parks, and cargo ships delivering EVs, should be considered a safety concern and necessary measures made.”
The Felicity Ace, a car carrier transporting largely Volkswagen and Porsche vehicles, including numerous electric vehicles, caught fire in February. While it’s still unclear if an EV ignited the fire, investigators believe the presence of the EVs definitely had a role in spreading the fire quickly. The fire got out of control and the crew was unable to put out the fire and was forced to abandon the ship. The ship finally sunk while being hauled back to port a few days later.
An EV battery might catch fire for a variety of reasons, which is why quality control is so important. Manufacturers are hurrying their EV development and perhaps taking unsafe shortcuts, according to industry whispers, motivated by competitiveness and the need to achieve financing objectives.
Cell Form & EV Fire
Cool running is a term used to describe the safety of electric vehicles. The form of the cell and the chemical composition of the battery are two crucial factors to consider when it comes to battery safety. When grouped together in battery modules that make up a pack, pouch cells – think cell phone battery — cluster closer together and give a higher space to energy ratio. Because of the air space around them, cylindrical cells – think of normal AA batteries – offer superior heat control and as a result, cylindrical cells are a little safer than flat ones.
Apart from the mentioned other reasons for the catching fire of EVs are,
Other Reason for EV Fire
Short circuit: A short circuit caused by anything from a wiring error to a rupture in the cells might result in an increase in temperature and eventually, a fire.
Faulty charging: Even a single contaminated cell may start a big fire, lighting itself and then causing the feared thermal runaway, which causes successive cells to ignite due to the rising temperature.
BMS Issues: Temperature control is the most important safety feature of any battery management system (BMS). This necessitates meticulous control of both charge and discharge speed and cycles; any error here can cause the battery to overheat and combust, and high ambient temperatures compound the problem.
Accidental Damage: Though protected very well, a battery getting punctured or even dented in an accident can lead to cell ruptures and thus ignition. An accident can also spill oil – yes EVs have oil for lubrication and cooling – onto hot electrical components which can ignite and lead to a bigger blaze.
Yes, EVs do catch fire but a very small percentage of them are at the risk. EVs catching fire is a relatively new thing for the common people and the officials. Since it is a new thing the best ways to fight them are yet to be found. EV fires differ from the other common type of fire in chemistry as for EV fires, oxygen from the atmosphere is not a necessity rendering the common fire fighting methods ineffective.
Once we unlock more information about EV fires, seizing them would not be a hard thing to do. Being all said, the fact is that, EVs are less prone to fires and more about that in coming posts.