Chances are high, by now, you have seen footage of an EV on hearth. It is a fairly scary sight. Evil, black smoke rolling out from underneath the automotive, presumably 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 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 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 12 months alone. What’s the actual fact in regards to 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 pleased for some exterior combustion, given half an opportunity.
Battery fires, nevertheless, are just a little extra nuanced. Your typical chemical cell in an EV is stuffed with unique elements that you could be be much less conversant in, however the identical mixture of supplies that creates a remarkably energy-dense supply of energy to your automotive also can create the proper 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 suggest 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 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 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 may also be brought on by bodily injury to the cell, which could occur in a catastrophic crash or in case you occur to drive over particles that someway manages to pierce the cell. This may trigger a brief within the battery, leading to a really fast launch of loads of vitality.
Because the cell overheats and the vitality is launched, the interior elements throughout the battery start to interrupt down, together with the flammable electrolyte. It kicks off a form of incendiary chain response that will not cease till all the battery is consumed. These fires can burn for hours, even re-igniting after they have been extinguished.
Fortunately, there’s loads of tech in trendy batteries to forestall that from occurring, together with superior thermal administration and large 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 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 straight 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 vehicles are far, far much less more likely to combust than vehicles 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 vehicles. Do the mathematics, and 0.004 % of EVs caught hearth that 12 months, in comparison with 0.08 % of ICE vehicles. (Be aware: That research previously lived right here however is unfortunately offline. An archived model of the research—although not in English—is out there 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 matter.)
It would not assist that EV fires are typically front-page information, despite the fact that they’re rarer than gasoline-vehicle fires. Nonetheless, 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 methods to work safely round EVs, carried out 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 vehicles, nevertheless, had a 0.1-percent probability.
Lastly, the Norwegian Defence Analysis Institution (FFI) has a research that takes a unique tack, taking a look at insurance coverage claims for automobile fires. Over the interval between 2006 and 2016, EV fires made up simply 4.8 % of general automobile fires. Curiously, that quantity dropped considerably over the interval of research. Taking a look at information from 2016, 2.3 % of auto fires have been resulting from EVs, seemingly pointing to newer vehicles 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 not less than partially submerged in salt water uncovered throughout hurricane Ian in 2022. 36 EVs caught hearth, or lower than 0.01 %.
New methods 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 answer? It’d require us re-thinking how we extinguish fires. The above video from Chilly Lower Methods exhibits one such method.
As defined by CTIF, the Worldwide Affiliation of Fireplace and Rescue Companies, the video exhibits a way of penetrating ignited EV batteries and injecting water straight 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 commonplace fare for emergency responders across the globe. And, in contrast to these Jaws, this form of firefighting gear may be efficient for extinguishing different forms of fires as properly.
As EVs develop into extra prevalent, anticipate to see options like this spreading, too, making an already uncommon occasion far much less traumatic and harmful.
