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 underneath the automotive, probably 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 simple to suppose they’re occurring on a regular basis.
A high-profile Chevy Bolt recall associated to attainable hearth danger 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 taking part in 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 actual reality in regards to 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 suited to inside combustion, nevertheless it’s very glad for some exterior combustion, given half an opportunity.
Battery fires, nonetheless, are somewhat extra nuanced. Your typical chemical cell in an EV is stuffed with unique parts 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 may create the right storm for a very ugly hearth.
YouTube
A gaggle of Teslas broken in a hearth in Germany.
To get all the small print, 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 probably may right here.
However the gist of it’s that lithium-ion battery fires usually occur as a consequence of one thing referred to as thermal runaway. That is when a battery cell begins to realize temperature quicker than it could actually shed it. This may occur for a wide range of causes, together with a flaw within the battery development, or a failure throughout charging.
It may also be brought on by bodily harm to the cell, which could occur in a catastrophic crash or if you happen to occur to drive over particles that by some means 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 parts inside 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 the whole 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 stop 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 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 possibly can 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 inside 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 loss of life 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 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 vehicles. Do the maths, and 0.004 % of EVs caught hearth that yr, in comparison with 0.08 % of ICE vehicles. (Notice: That research previously lived right here however is unfortunately offline. An archived model of the research—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 typically front-page information, although they’re rarer than gasoline-vehicle fires. Nevertheless, they do pose distinctive challenges due to how exhausting they are often to completely extinguish.
EV Fireplace Protected, 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 probability of catching hearth globally. ICE vehicles, nonetheless, 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 car fires. Over the interval between 2006 and 2016, EV fires made up simply 4.8 % of general car fires. Curiously, that quantity dropped considerably over the interval of research. knowledge from 2016, 2.3 % of car fires had been as a consequence of EVs, seemingly pointing to more moderen vehicles being even safer.
And what about saltwater intrusion? The numbers are considerably tougher to trace since it is a uncommon phenomenon, however in accordance with NHTSA analysis, of the between 3,000 and 5,000 EVs had been at the very least partially submerged in salt water uncovered throughout hurricane Ian in 2022. 36 EVs caught hearth, or lower than 0.01 %.
New strategies 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 resolution? It would require us re-thinking how we extinguish fires. The above video from Chilly Minimize Programs reveals one such method.
As defined by CTIF, the Worldwide Affiliation of Fireplace and Rescue Providers, the video reveals a way of penetrating ignited EV batteries and injecting water straight 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 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 commonplace fare for emergency responders across the globe. And, not like these Jaws, this form of firefighting tools 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.
