Are electric cars more likely to catch fire?

Another headline about a fiery Tesla crash has people wondering if those lithium ion batteries are safe."A bat...

Posted: May 17, 2018 6:59 PM
Updated: May 17, 2018 6:59 PM

Another headline about a fiery Tesla crash has people wondering if those lithium ion batteries are safe.

"A battery powered vehicle having a fire incident is newsworthy. A gasoline powered vehicle having a fire is newsworthy only if it stops traffic," said Steven Risser, senior research leader at Battelle, a nonprofit research and development firm, and one of the leading experts on the risk of fires in electric vehicles.

Here's the answers to questions about the risk of electric car fires:

Are electric cars more likely to catch fire?

The simple answer is probably not. Chances are they might even be safer, though it's tough to say that definitively.

"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," according to the results of an in-depth investigation into the relative fire risks of the two types of vehicles conducted by Battelle for the National Highway Traffic Safety Administration last fall.

About 174,000 vehicle fires were reported in the United States in 2015, the most recent year for which statistics are available from the National Fire Protection Association. Virtually all of those fires involved gasoline powered cars. That works out to about one every three minutes.

Tesla claims that gasoline powered cars are about 11 times more likely to catch fire than a Tesla. It says the best comparison is fires per 1 billion miles driven. It says the 300,000 Teslas on the road have been driven a total of 7.5 billion miles, and about 40 fires have been reported. That works out to five fires for every billion miles traveled, compared to a rate of 55 fires per billion miles traveled in gasoline cars.

But Risser said still there's not enough data to make valid comparisons at this point.

How do lithium ion batteries powering electric vehicles catch fire?

There have been some other high profile fire problems involving lithium ion batteries in other uses - in cell phones, in laptops and even in Boeing passenger jets. But so far the fires involving electric vehicles have been caused by some kind of crash or other damage to the battery while driving.

"Tesla's battery packs rarely incur serious damage, and when they have, the accident was highly unusual or severe," said Tesla's statement.

What happens with a lithium ion battery fire is typically a short circuit within one or more of the battery's cells, which generates heat. The heat can then ignite the chemicals within the battery. That can cause problems in the adjoining cells and lead to the condition known as "thermal runaway" in which the fire spreads and builds. That's apparently what happened in a fatal Tesla crash in Switzerland last week.

How else is a lithium ion battery fire different from a gasoline fire?

The biggest difference is the time it takes to ignite. Gasoline fires start almost immediately when gasoline comes in contact with a spark or flame, and spreads rapidly. Battery fires typically take some time to achieve the heat necessary to start the fire.

In some instances, that delay is very good news. It can let the occupants of a car involved in a crash to get out of the vehicle before the fire starts. But it can pose its own problems. Sometimes a battery can be damaged, perhaps by the car running over some debris, and the driver might not be aware of the damage. And then a fire can start well after the initial incident. That could theoretically cause a fire after the car is parked in a garage.

And even when the battery fire is obvious, Tesla warns first responders that it can take 24 hours for a battery fire to be fully extinguished.

Can the fire risk for electric cars be reduced?

Yes. And Risser and others say that is likely to happen.

Research is taking place for new materials that might not only make batteries lighter and more efficient, but could possibly make them safer. "Gasoline is a very risky material. We have had 130 years of designs and experience to make a gasoline powered vehicle as safe as possible. We're still at early stages of understanding how to make lithium ion batteries safe," he said.

Mississippi Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 93556

Reported Deaths: 2810
CountyConfirmedDeaths
Hinds6974155
DeSoto541155
Harrison373272
Jackson338867
Madison320886
Rankin319075
Lee260667
Jones242078
Forrest239070
Washington217971
Lafayette208439
Lauderdale1999124
Bolivar179465
Oktibbeha175050
Lamar163134
Neshoba1536103
Panola144027
Sunflower141744
Lowndes139957
Warren138150
Leflore136980
Pontotoc123416
Pike121248
Monroe118865
Scott116425
Copiah116233
Coahoma112327
Holmes109258
Marshall107615
Lincoln106753
Grenada106135
Yazoo103829
Simpson101143
Union97824
Tate95137
Leake93937
Adams91936
Wayne87721
Pearl River86550
Marion84133
Prentiss81117
Covington80522
Alcorn77311
Itawamba76221
Newton75723
Tallahatchie75418
George74913
Winston72419
Tishomingo65837
Chickasaw65524
Tippah64216
Attala64125
Walthall59325
Clay57817
Hancock56121
Jasper55415
Noxubee54315
Clarke53539
Smith52314
Calhoun50612
Tunica47913
Montgomery45520
Claiborne45216
Lawrence42512
Yalobusha41714
Perry40718
Quitman3745
Humphreys37315
Stone35511
Greene34517
Webster33113
Jefferson Davis32511
Carroll31212
Amite31110
Wilkinson30217
Kemper28615
Sharkey26312
Jefferson2429
Benton2191
Franklin1893
Choctaw1795
Issaquena1033
Unassigned00

Alabama Coronavirus Cases

Confirmed Cases: 131405

Reported Deaths: 2292
CountyConfirmedDeaths
Jefferson19015337
Mobile13066289
Montgomery8674173
Madison758375
Tuscaloosa7240114
Lee571359
Shelby568450
Baldwin506149
Marshall383543
Etowah335547
Calhoun333839
Morgan319726
Houston270822
Elmore254947
DeKalb235519
St. Clair223435
Walker222680
Talladega206926
Limestone199519
Cullman184517
Dallas174826
Franklin174328
Russell17132
Autauga169024
Lauderdale164633
Colbert160626
Escambia156225
Blount155114
Jackson150611
Chilton148527
Dale133043
Covington130927
Coffee12778
Pike11559
Tallapoosa113683
Chambers113042
Clarke104917
Marion94228
Butler90938
Barbour8357
Winston70912
Marengo69919
Lowndes64827
Pickens63514
Bibb63210
Hale61528
Randolph60812
Bullock58714
Lawrence58520
Monroe5758
Geneva5724
Cherokee56516
Washington54613
Clay5427
Perry5376
Wilcox53111
Conecuh52311
Crenshaw52331
Macon47720
Henry4724
Fayette4219
Sumter41819
Lamar3462
Choctaw34512
Cleburne3236
Greene30015
Coosa1643
Out of AL00
Unassigned00
Tupelo
Clear
68° wxIcon
Hi: 78° Lo: 58°
Feels Like: 68°
Columbus
Clear
67° wxIcon
Hi: 80° Lo: 58°
Feels Like: 67°
Oxford
Clear
66° wxIcon
Hi: 78° Lo: 57°
Feels Like: 66°
Starkville
Clear
66° wxIcon
Hi: 78° Lo: 56°
Feels Like: 66°
WTVA Radar
WTVA Temperatures
WTVA Severe Weather