Myth: EVs are more prone to catch fire and more danÂgerÂous than gas cars.
Myth BustÂed: Just as it’s true that your gas car can catch fire, it is true that an elecÂtric vehiÂcle (EV) can catch fire. HowÂevÂer, EVs are some of the top-ratÂed cars for safeÂty and are less likeÂly to catch fire comÂpared to gas cars.
AccordÂing to an invesÂtiÂgaÂtion by BatÂtelle for the NationÂal HighÂway TrafÂfic SafeÂty AdminÂisÂtraÂtion, “The propenÂsiÂty and severÂiÂty of fires and exploÂsions from … lithiÂum-ion batÂtery sysÂtems are anticÂiÂpatÂed to be someÂwhat comÂpaÂraÂble to or perÂhaps slightÂly less than those for gasoÂline or diesel vehicÂuÂlar fuels…”.
LithiÂum-ion (Li-ion) batÂtery fires are difÂferÂent from gasoÂline fires as they take time to achieve the necÂesÂsary heat to ignite (called therÂmal runÂaway), whereÂas gasoÂline ignites immeÂdiÂateÂly when it encounÂters a spark or flame. Because of this, Li-ion batÂterÂies have a sigÂnifÂiÂcantÂly lowÂer risk of causÂing a fire or exploÂsion. When they do, it is usuÂalÂly a result of sigÂnifÂiÂcant exterÂnal damÂage. BatÂtery packs in elecÂtric vehiÂcles rarely encounter seriÂous damÂage, and it is often the result of a highÂly unusuÂal or severe accident.
StaÂtisÂtics from 2015 showed that 174,000 vehiÂcle fires were reportÂed, and almost all of them involved gasoÂline vehiÂcles. TesÂla claims that gasoÂline cars are 11x more likeÂly to catch fire than a TesÂla, and that the best comÂparÂiÂson of safeÂty is fires per bilÂlion miles driÂven. If we comÂpare using this method, there are approxÂiÂmateÂly five EV fires for every bilÂlion miles travÂeled, comÂpared to 55 fires per bilÂlion miles travÂeled in gasoÂline cars. Although this analyÂsis is promisÂing, there is still not enough data on elecÂtric vehiÂcles to make definÂiÂtive comÂparÂisons at this point.
The techÂnolÂoÂgy used in EVs is specifÂiÂcalÂly designed to preÂvent therÂmal runÂaway. The batÂterÂies are surÂroundÂed by a coolÂing shroud filled with liqÂuid coolant to preÂvent them from overÂheatÂing. If the batÂterÂies do manÂage to overÂheat even with the coolant, all EV batÂterÂies are installed in an array whose clusÂters are sepÂaÂratÂed by addiÂtionÂal fireÂwalls to limÂit the amount of damÂage in the case of malÂfuncÂtion. HowÂevÂer, because Li-ion batÂtery fires are still new to fire departÂments and emerÂgency teams, it can take sigÂnifÂiÂcantÂly more effort to tame the fire. Because Li-ion batÂterÂies have enerÂgy stored in the batÂtery pack, therÂmal runÂaway can take over and cause the fire to flare for sevÂerÂal hours, requirÂing sigÂnifÂiÂcant amounts of water to get it under control.
While we have been seeÂing more reports in the news about Li-ion batÂtery fires in TesÂlas and with the Chevy Bolt recall, it’s imporÂtant to rememÂber that EV batÂtery fires garÂner sigÂnifÂiÂcantÂly more news comÂpared to when a gas engine catchÂes fire. This is because of the increased scrutiÂny of the EV indusÂtry and the relÂaÂtive novÂelÂty of this techÂnolÂoÂgy. HowÂevÂer, every fire is cause for conÂcern and the car manÂuÂfacÂturÂers are workÂing to fix the probÂlems, includÂing the manÂuÂfacÂturÂing defects found to increase risk of fire in the Chevy Bolts. To reduce the risk of fires in malÂfuncÂtionÂing elecÂtric modÂels, it is imporÂtant to folÂlow the recÂomÂmenÂdaÂtions of the manÂuÂfacÂturÂer, includÂing mainÂtainÂing a charge between 20–80% and avoidÂing leavÂing the car chargÂing unatÂtendÂed overnight.
The most imporÂtant thing to rememÂber is that these are earÂly days for develÂopÂing EV batÂtery techÂnolÂoÂgy and safeÂty. As more research is comÂpletÂed and more data becomes availÂable, these vehiÂcles will become even safer.
Source 1: Isidore, Chris. “Are ElecÂtric Cars More LikeÂly to Catch Fire?” CNNÂMoney, Cable News NetÂwork, 17 May 2018, money.cnn.com/2018/05/17/news/companies/electric-car-fire-risk/index.html.
Source 2: McConnell, MalÂcolm. “Are ElecÂtric Cars Safer in ColÂliÂsions?” Allen, Allen, Allen & Allen, 26 Sept. 2019, www.allenandallen.com/are-electric-cars-safer-in-collisions/.
Source 3: MorÂris, Charles. “TesÂla says fire inciÂdents are 11 times lowÂer for its vehiÂcles than for the averÂage US vehiÂcle.” Charged MagÂaÂzine. 15 August 2021. https://chargedevs.com/newswire/tesla-says-fire-incidents-are-11-times-lower-for-its-vehicles-than-for-the-average-us-vehicle/.
Source 4: Crothers, Brooke. Are ElecÂtric Cars Safe? AnothÂer Chevy Bolt Caught Fire, A TesÂla ModÂel S Plaid Did Too. Forbes. 11 July 2021. https://www.forbes.com/sites/brookecrothers/2021/07/11/are-electric-cars-safe-another-chevy-bolt-caught-fire-a-tesla-model-s-plaid-did-too/.
Source 5: Ramey, Jay. GM Recalls Every Chevy Bolt Made over BatÂtery Fire Risk. Yahoo News. 23 August 2021. https://news.yahoo.com/gm-recalls-every-chevy-bolt-151300260.html.