Likelihood is, by now, you’ve got seen footage of an EV on hearth. It is a reasonably scary sight. Evil, black smoke rolling out from below the automobile, presumably lit up by capturing sparks and ceaseless flames that seemingly no quantity of water can extinguish. These fires are so typically highlighted on the information and social media that it is simple to suppose they’re occurring on a regular basis.
A high-profile Chevy Bolt recall associated to doable hearth threat definitely 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 taking part in with matches in a wooden shed.
But when that have 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 reality concerning the hearth threat of EVs? That is what we’re right here to seek 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 inner combustion, however it’s very completely satisfied for some exterior combustion, given half an opportunity.
Battery fires, nevertheless, are a bit extra nuanced. Your typical chemical cell in an EV is stuffed with unique parts that you could be be much less acquainted with, however the identical mixture of supplies that creates a remarkably energy-dense supply of energy on your automobile may create the right storm for a extremely ugly hearth.
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A bunch of Teslas broken in a fireplace in Germany.
To get all the main points, I extremely advocate you take a look at “The Science of Fireplace and Explosion Hazards from Lithium-Ion Batteries” by Adam Barowy, analysis engineer at UL’s Fireplace Security Analysis Institute. It goes into far more element than I presumably might right here.
However the gist of it’s that lithium-ion battery fires sometimes occur as a consequence of one thing known as thermal runaway. That is when a battery cell begins to achieve temperature sooner than it will probably shed it. This will occur for a wide range of causes, together with a flaw within the battery building, or a failure throughout charging.
It may also be brought on by bodily injury to the cell, which could occur in a catastrophic crash or when you occur to drive over particles that someway manages to pierce the cell. This will trigger a brief within the battery, leading to a really fast launch of lots of vitality.
Because the cell overheats and the vitality is launched, the inner parts throughout the battery start to interrupt down, together with the flammable electrolyte. It kicks off a kind of incendiary chain response that won’t cease till the complete battery is consumed. These fires can burn for hours, even re-igniting after they have been extinguished.
Fortunately, there’s lots of tech in trendy batteries to forestall that from occurring, 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 way of Florida two years in the past, there have been once more EV fires, together with one other Tesla Mannequin X.
You may 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 throughout 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 inner 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 Prime Gear, IEEE Spectrum and The Guardian. All three are nice studying if you wish to study extra about this subject.)
It does not assist that EV fires are usually front-page information, regardless that they’re rarer than gasoline-vehicle fires. Nevertheless, they do pose distinctive challenges due to how onerous they are often to completely extinguish.
EV Fireplace Protected, an Australian initiative for educating emergency responders about learn how to work safely round EVs, performed its personal survey and got here up with comparable numbers. In line with that analysis, between 2010 and 2020, a given EV had a 0.0012-percent probability of catching hearth globally. ICE automobiles, nevertheless, had a 0.1-percent probability.
Lastly, the Norwegian Defence Analysis Institution (FFI) has a examine that takes a distinct tack, insurance coverage claims for car fires. Over the interval between 2006 and 2016, EV fires made up simply 4.8 p.c of total car fires. Curiously, that quantity dropped considerably over the interval of examine. knowledge from 2016, 2.3 p.c of car fires have been as a consequence of EVs, seemingly pointing to more moderen automobiles being even safer.
And what about saltwater intrusion? The numbers are considerably more durable to trace since it is a uncommon phenomenon, however in line with NHTSA analysis, of the between 3,000 and 5,000 EVs have been no less than 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 once they do occur. What is the resolution? It’d require us re-thinking how we extinguish fires. The above video from Chilly Minimize Programs exhibits one such approach.
As defined by CTIF, the Worldwide Affiliation of Fireplace and Rescue Providers, the video exhibits a way of penetrating ignited EV batteries and injecting water immediately into their inner construction. The result’s an EV battery put out in minutes, with solely a small fraction of the quantity of water that may in any other case be required.
Some specialised tools is required to make use of this method, however nothing extra unique than the Jaws of Life (extra formally, the Hurst Rescue Instruments), that are customary fare for emergency responders across the globe. And, in contrast to these Jaws, this kind of firefighting tools may be efficient for extinguishing different kinds of fires as properly.
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.
