Likelihood is, by now, you have seen footage of an EV on hearth. It is a reasonably scary sight. Evil, black smoke rolling out from beneath the automobile, probably lit up by taking pictures sparks and ceaseless flames that seemingly no quantity of water can extinguish. These fires are so usually highlighted on the information and social media that it is simple to suppose they’re taking place on a regular basis.
A high-profile Chevy Bolt recall associated to doable hearth danger actually hasn’t helped that public notion, offering ever extra ammunition to anti-EV pundits who’d have you ever consider that parking an electrical automobile in your storage is pretty much as good as enjoying with matches in a wooden shed.
But when that had been the reality, would not we be seeing a heck of much more fires? Individuals purchased greater than a half-million EVs within the first half of this yr alone. What’s the true fact concerning the hearth danger of EVs? That is what we’re right here to search out out in our newest installment of EV Myths, Discharged.
What causes EV fires?
Everybody is aware of what it takes to set gasoline on hearth: A tiny little spark will do. Gasoline’s flamable nature makes it ideally fitted to inside combustion, nevertheless it’s very pleased for some exterior combustion, given half an opportunity.
Battery fires, nonetheless, are somewhat extra nuanced. Your typical chemical cell in an EV is filled with unique parts that you could be be much less aware of, however the identical mixture of supplies that creates a remarkably energy-dense supply of energy to your automobile also can create the right storm for a extremely ugly hearth.
YouTube
A gaggle of Teslas broken in a fireplace in Germany.
To get all the main points, I extremely advocate you try “The Science of Hearth and Explosion Hazards from Lithium-Ion Batteries” by Adam Barowy, analysis engineer at UL’s Hearth Security Analysis Institute. It goes into far more element than I probably might right here.
However the gist of it’s that lithium-ion battery fires usually occur resulting from one thing referred to as thermal runaway. That is when a battery cell begins to achieve temperature sooner than it may well shed it. This may occur for quite a lot of causes, together with a flaw within the battery building, or a failure throughout charging.
It will also be attributable to bodily harm to the cell, which could occur in a catastrophic crash or when you occur to drive over particles that one way or the other manages to pierce the cell. This may trigger a brief within the battery, leading to a really speedy launch of numerous vitality.
Because the cell overheats and the vitality is launched, the inner parts inside the battery start to interrupt down, together with the flammable electrolyte. It kicks off a kind of incendiary chain response that will not cease till your entire battery is consumed. These fires can burn for hours, even re-igniting after they have been extinguished.
Fortunately, there’s numerous tech in trendy batteries to stop that from taking place, together with superior thermal administration and big quantities of crash safety, just like the carbon-fiber underbody safety within the electrical Mercedes-Benz G-Class, or the aluminum extrusions and forged parts that Audi stacks across the cells in the Audi Q8 E-Tron.
Saltwater EV fires
Within the wake of hurricane Helene, a video of a Tesla Mannequin X catching hearth has been making the rounds. That automobile was uncovered to lower than a foot of the storm wake on the western coast of Florida and later caught hearth, tragically destroying the house. This is not the primary time this we’ve seen a state of affairs like this. When hurricane Ian cruised by Florida two years in the past, there have been once more EV fires, together with one other Tesla Mannequin X.
You’ll be able to learn extra particulars on the issue in our reporting right here, however the gist of it’s that extended publicity to saltwater can breach the battery’s protecting seals. Shorts can kind inside the pack, both immediately by the conductive saltwater, or by deposited salt after the water recedes. These shorts can then result in a thermal runaway situation.
EV hearth numbers
Okay, let’s look into the foundation of the factor: Are EVs actually fire-prone dying traps? There have been a number of research on the topic, and all come to the identical conclusion that electrical automobiles are far, far much less more likely to combust than automobiles with inside combustion engines.
One of many extra complete research comes from Sweden’s Civil Contingencies Company (the MSB), which in 2022 cited 23 fires from a pool of 611,000 EVs in service. That compares to three,400 fires in 4.4 million fuel-burning automobiles. Do the maths, and 0.004 p.c of EVs caught hearth that yr, in comparison with 0.08 p.c of ICE automobiles. (Observe: That examine previously lived right here however is unfortunately offline. An archived model of the examine—although not in English—is on the market right here. It has been cited by High Gear, IEEE Spectrum and The Guardian. All three are nice studying if you wish to be taught extra about this subject.)
It would not assist that EV fires are usually front-page information, though they’re rarer than gasoline-vehicle fires. Nevertheless, they do pose distinctive challenges due to how exhausting they are often to completely extinguish.
EV Hearth Secure, an Australian initiative for educating emergency responders about the way to work safely round EVs, performed its personal survey and got here up with comparable numbers. In response to that analysis, between 2010 and 2020, a given EV had a 0.0012-percent likelihood of catching hearth globally. ICE automobiles, nonetheless, had a 0.1-percent likelihood.
Lastly, the Norwegian Defence Analysis Institution (FFI) has a examine that takes a distinct tack, insurance coverage claims for automobile fires. Over the interval between 2006 and 2016, EV fires made up simply 4.8 p.c of general automobile fires. Curiously, that quantity dropped considerably over the interval of examine. information from 2016, 2.3 p.c of car fires had been resulting from EVs, seemingly pointing to newer automobiles being even safer.
And what about saltwater intrusion? The numbers are considerably tougher to trace since it is a uncommon phenomenon, however in keeping with NHTSA analysis, of the between 3,000 and 5,000 EVs had been a minimum of partially submerged in salt water uncovered throughout hurricane Ian in 2022. 36 EVs caught hearth, or lower than 0.01 p.c.
New strategies for placing out EV fires
So, that conclusively exhibits that EV fires are extraordinarily uncommon, however as defined above, they are often extremely violent after they do occur. What is the answer? It would require us re-thinking how we extinguish fires. The above video from Chilly Lower Techniques exhibits one such approach.
As defined by CTIF, the Worldwide Affiliation of Hearth and Rescue Companies, the video exhibits a way of penetrating ignited EV batteries and injecting water immediately into their inside construction. The result’s an EV battery put out in minutes, with solely a small fraction of the quantity of water that might in any other case be required.
Some specialised gear is required to make use of this system, however nothing extra unique than the Jaws of Life (extra formally, the Hurst Rescue Instruments), that are normal fare for emergency responders across the globe. And, not like these Jaws, this kind of firefighting gear might be efficient for extinguishing different forms of fires as nicely.
As EVs grow to be extra prevalent, anticipate to see options like this spreading, too, making an already uncommon occasion far much less traumatic and harmful.
