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 automotive, presumably lit up by capturing 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 easy to assume they’re occurring on a regular basis.
A high-profile Chevy Bolt recall associated to attainable 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 automotive in your storage is nearly as good as enjoying 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 actual fact concerning the hearth threat 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 suited to inner combustion, but it surely’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 filled with unique elements that you could be be much less acquainted with, however the identical mixture of supplies that creates a remarkably energy-dense supply of energy to your automotive can even create the proper storm for a very 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 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 because of one thing referred to as thermal runaway. That is when a battery cell begins to achieve temperature quicker than it will possibly shed it. This could occur for a wide range of causes, together with a flaw within the battery building, or a failure throughout charging.
It can be brought on by bodily harm to the cell, which could occur in a catastrophic crash or in the event you occur to drive over particles that one way or the other manages to pierce the cell. This could trigger a brief within the battery, leading to a really speedy launch of lots of power.
Because the cell overheats and the power is launched, the interior elements throughout the battery start to interrupt down, together with the flammable electrolyte. It kicks off a type 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 lots of tech in fashionable 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 solid elements 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 automotive 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 scenario like this. When hurricane Ian cruised by means 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 type throughout the pack, both instantly 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 basis of the factor: Are EVs actually fire-prone demise 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. (Word: That research previously lived right here however is unfortunately offline. An archived model of the research—although not in English—is accessible right here. It has been cited by Prime Gear, IEEE Spectrum and The Guardian. All three are nice studying if you wish to be taught extra about this subject.)
It does not assist that EV fires are typically front-page information, regardless that they’re rarer than gasoline-vehicle fires. Nevertheless, they do pose distinctive challenges due to how laborious they are often to totally extinguish.
EV Fireplace Secure, an Australian initiative for educating emergency responders about work safely round EVs, carried out 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, nevertheless, had a 0.1-percent likelihood.
Lastly, the Norwegian Defence Analysis Institution (FFI) has a research that takes a special tack, insurance coverage claims for automobile fires. Over the interval between 2006 and 2016, EV fires made up simply 4.8 p.c of total automobile fires. Curiously, that quantity dropped considerably over the interval of research. information from 2016, 2.3 p.c of auto fires have been because of EVs, seemingly pointing to newer 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 accordance with NHTSA analysis, of the between 3,000 and 5,000 EVs have 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 methods for placing out EV fires
So, that conclusively reveals that EV fires are extraordinarily uncommon, however as defined above, they are often extremely violent after they do occur. What is the answer? It’d require us re-thinking how we extinguish fires. The above video from Chilly Minimize Techniques reveals one such method.
As defined by CTIF, the Worldwide Affiliation of Fireplace and Rescue Companies, the video reveals a way of penetrating ignited EV batteries and injecting water instantly 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 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, in contrast to these Jaws, this type of firefighting gear could be efficient for extinguishing different sorts of fires as properly.
As EVs turn out to be extra prevalent, anticipate to see options like this spreading, too, making an already uncommon occasion far much less traumatic and harmful.
