Myth Buster: EVs Catch Fire More than Gas Cars

June 17, 2021

Myth: EVs are more prone to catch fire and more dan­ger­ous than gas cars.

Myth Bust­ed: Just as it’s true that your gas car can catch fire, it is true that an elec­tric vehi­cle (EV) can catch fire. How­ev­er, EVs are some of the top-rat­ed cars for safe­ty and are less like­ly to catch fire com­pared to gas cars.

Accord­ing to an inves­ti­ga­tion by Bat­telle for the Nation­al High­way Traf­fic Safe­ty Admin­is­tra­tion, “The propen­si­ty and sever­i­ty of fires and explo­sions from … lithi­um-ion bat­tery sys­tems are antic­i­pat­ed to be some­what com­pa­ra­ble to or per­haps slight­ly less than those for gaso­line or diesel vehic­u­lar fuels…”.

Lithi­um-ion (Li-ion) bat­tery fires are dif­fer­ent from gaso­line fires as they take time to achieve the nec­es­sary heat to ignite (called ther­mal run­away), where­as gaso­line ignites imme­di­ate­ly when it encoun­ters a spark or flame. Because of this, Li-ion bat­ter­ies have a sig­nif­i­cant­ly low­er risk of caus­ing a fire or explo­sion. When they do, it is usu­al­ly a result of sig­nif­i­cant exter­nal dam­age. Bat­tery packs in elec­tric vehi­cles rarely encounter seri­ous dam­age, and it is often the result of a high­ly unusu­al or severe accident.

Sta­tis­tics from 2015 showed that 174,000 vehi­cle fires were report­ed, and almost all of them involved gaso­line vehi­cles. Tes­la claims that gaso­line cars are 11x more like­ly to catch fire than a Tes­la, and that the best com­par­i­son of safe­ty is fires per bil­lion miles dri­ven. If we com­pare using this method, there are approx­i­mate­ly five EV fires for every bil­lion miles trav­eled, com­pared to 55 fires per bil­lion miles trav­eled in gaso­line cars. Although this analy­sis is promis­ing, there is still not enough data on elec­tric vehi­cles to make defin­i­tive com­par­isons at this point.

The tech­nol­o­gy used in EVs is specif­i­cal­ly designed to pre­vent ther­mal run­away. The bat­ter­ies are sur­round­ed by a cool­ing shroud filled with liq­uid coolant to pre­vent them from over­heat­ing. If the bat­ter­ies do man­age to over­heat even with the coolant, all EV bat­ter­ies are installed in an array whose clus­ters are sep­a­rat­ed by addi­tion­al fire­walls to lim­it the amount of dam­age in the case of mal­func­tion.  How­ev­er, because Li-ion bat­tery fires are still new to fire depart­ments and emer­gency teams, it can take sig­nif­i­cant­ly more effort to tame the fire. Because Li-ion bat­ter­ies have ener­gy stored in the bat­tery pack, ther­mal run­away can take over and cause the fire to flare for sev­er­al hours, requir­ing sig­nif­i­cant amounts of water to get it under control.

While we have been see­ing more reports in the news about Li-ion bat­tery fires in Tes­las and with the Chevy Bolt recall, it’s impor­tant to remem­ber that EV bat­tery fires gar­ner sig­nif­i­cant­ly more news com­pared to when a gas engine catch­es fire. This is because of the increased scruti­ny of the EV indus­try and the rel­a­tive nov­el­ty of this tech­nol­o­gy. How­ev­er, every fire is cause for con­cern and the car man­u­fac­tur­ers are work­ing to fix the prob­lems, includ­ing the man­u­fac­tur­ing defects found to increase risk of fire in the Chevy Bolts. To reduce the risk of fires in mal­func­tion­ing elec­tric mod­els, it is impor­tant to fol­low the rec­om­men­da­tions of the man­u­fac­tur­er, includ­ing main­tain­ing a charge between 20–80% and avoid­ing leav­ing the car charg­ing unat­tend­ed overnight.

The most impor­tant thing to remem­ber is that these are ear­ly days for devel­op­ing EV bat­tery tech­nol­o­gy and safe­ty. As more research is com­plet­ed and more data becomes avail­able, these vehi­cles will become even safer.

Source 1: Isidore, Chris. “Are Elec­tric Cars More Like­ly to Catch Fire?” CNN­Money, Cable News Net­work, 17 May 2018, money.cnn.com/2018/05/17/news/companies/electric-car-fire-risk/index.html.

Source 2: McConnell, Mal­colm. “Are Elec­tric Cars Safer in Col­li­sions?” Allen, Allen, Allen & Allen, 26 Sept. 2019, www.allenandallen.com/are-electric-cars-safer-in-collisions/.

Source 3: Mor­ris, Charles. “Tes­la says fire inci­dents are 11 times low­er for its vehi­cles than for the aver­age US vehi­cle.” Charged Mag­a­zine. 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 Elec­tric Cars Safe? Anoth­er Chevy Bolt Caught Fire, A Tes­la Mod­el 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 Bat­tery Fire Risk. Yahoo News. 23 August 2021. https://news.yahoo.com/gm-recalls-every-chevy-bolt-151300260.html.

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