Another Tesla Fatality with Fire

[Mark W]

Some interesting numbers here and in other IIHS reports. While some of these 2014 no-deaths vehicles are low-volume, I was surprised that the Jeep Cherokee 4WD made it to the list.

The only numbers I could find relating to Tesla was on this listing of personal injury protection claims. Here, the Model S made it into the lowest claim frequency grouping, but wasn't the lowest. Not sure how so many sportscars had lower claim frequencies,and not SUVs, but maybe it has something to do with "per 1,000 insured vehicle years. (statistics aren't my strong suit)
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Another great example of the need to be careful as to how you analyze statistics. The most striking thing that sticks out here is that the lowest rates are all expensive luxury cars, and all highest rates are among the cheapest cars you can buy. So, what does that mean? The luxury automakers would tell you (as Tesla does) that it means their cars are better built and safer. I would guess that is true to some extent. What else could it mean? As was mentioned above, wealthier people will be driving the more expensive cars. I would think they would get in less accidents. Wealthier people would be older and more careful. What would also be a factor is that many of these cars are more babied by their owners. Maintained better, in some cases only driven in better weather, etc.

So, when Elon says that you are 6 times (or whatever the figure is that he uses) less likely to be injured or killed based on per hours driven statistics, be careful about what that really means.

Back to the main point here, I don't think you are any more likely to burn in a Tesla crash than in a gas car crash. That is not based on any good facts, just from what appears to be logical to me. It seems that gasoline would be more likely to burn in a crash than batteries. I could be very wrong. And yes, we are hearing about every Tesla fatality and fire because Teslas are the IT car with the new technology, and everyone wants to tear down successful people and companies at every chance they get.

 

[Martin Williams]

Just no. This is not physically possible. All the cells are within modules, all the modules are secured within the pack. Nothing moves.

In a severe crash everything moves! It's only a question of by how much. Half a ton of batteries stopping from 15 or 20 metres a second in perhaps a tenth of a second is going to be damaged. Musk cannot stop it, his engineers cannot stop it, all the King's horses and all the King's men cannot stop it. Far from being impossible, it is impossible to STOP it happening.

The questions to be answered are whether the distortion or crushing of a cell will cause overheating and will that cause the adjacent cells to do the same.

 

[Domenick]

In a severe crash everything moves! It's only a question of by how much. Half a ton of batteries stopping from 15 or 20 metres a second in perhaps a tenth of a second is going to be damaged. Musk cannot stop it, his engineers cannot stop it, all the King's horses and all the King's men cannot stop it. Far from being impossible, it is impossible to STOP it happening.

The questions to be answered are whether the distortion or crushing of a cell will cause overheating and will that cause the adjacent cells to do the same.

The cars undergo extensive crash testing. That question has been answered.

 

[Martin Williams]

Are you claiming that the battery blazes which took place after severe crashes did not occur? That is the implication of your statement, is it not?

 

[Pushmi-Pullyu]

But comparing fire risk of modern Tesla's against the entire fleet of licensed vehicles is misleading as most cars are 10+ years old... Should compare the fire risk of Tesla, to other BEV, and modern ICE cars in competitive segments. That is a real comparison.

This oft-repeated argument is getting a bit old by now. The oldest production Tesla cars are now 10 years old, certainly long enough to properly assess the danger of fire... or in this case, the relative lack of danger!

​

 

[Pushmi-Pullyu]

That is the implication of your statement, is it not?

No.

 

[David Green]

Are you claiming that the battery blazes which took place after severe crashes did not occur? That is the implication of your statement, is it not?

Teslas "seem" to have a fairly high rate of major fires after severe accidents, and I would guess more fires overall if compared to same year and quantity BMW 7, Mercedes S, Cadillac CT6, Lexus LS, and other cars in that class. Whats more scary is that Tesla seems to also have more trouble with fires then other BEV makers. Now I am sure after saying that my I-Pace will burn my house down while charging. haha!

Now, before I get flamed... "seem to" is not stating that as a fact, but more of an observation. I am not trolling, hating, or anything of the sort.

 

[David Green]

The cars undergo extensive crash testing. That question has been answered.

Crash testing is all predictable, and you know the parameters before you design the car, in the real world crashes are not predictable, and as a result crash testing just sets a baseline.

 

[Domenick]

Are you claiming that the battery blazes which took place after severe crashes did not occur? That is the implication of your statement, is it not?

No, that is not the implication of my statement. The batteries that have caught fire in crashes have done so after the integrity of the pack has been compromised. Deceleration doesn't compromise the integrity of the pack. A considerable impact is needed for that.

Take the most recent firetruck crash, for example. 60 mph to zero mph: sudden deceleration and no fire.
Silicon Valley crash: hit concrete highway barrier with an impact greater than the front crumple zone could absorb and broke open the actual pack and crushed cells resulting in fire.

 

[David Green]

No, that is not the implication of my statement. The batteries that have caught fire in crashes have done so after the integrity of the pack has been compromised. Deceleration doesn't compromise the integrity of the pack. A considerable impact is needed for that.

Take the most recent firetruck crash, for example. 60 mph to zero mph: sudden deceleration and no fire.
Silicon Valley crash: hit concrete highway barrier with an impact greater than the front crumple zone could absorb and broke open the actual pack and crushed cells resulting in fire.

Yes, I understood your point. But 2 Tesla's in a week have burned up with people inside. We have to re-look at the safety systems.. How many bolts have gone up in flames, I know at least 1 Bolt had the battery pack compromised in a head on collision with no fire.

 

[Domenick]

Teslas "seem" to have a fairly high rate of major fires after severe accidents, and I would guess more fires overall if compared to same year and quantity BMW 7, Mercedes S, Cadillac CT6, Lexus LS, and other cars in that class. Whats more scary is that Tesla seems to also have more trouble with fires then other BEV makers. Now I am sure after saying that my I-Pace will burn my house down while charging. haha!

Now, before I get flamed... "seem to" is not stating that as a fact, but more of an observation. I am not trolling, hating, or anything of the sort.

I can certainly see how Tesla might seem more flammable than other luxury cars right now, but I'd like to see the hard data before making that pronouncement.

I do think the Tesla/Panasonic cells are more reactive than those use by other manufacturers. Tesla decided to go with cells that have the highest energy storage potential and then packaged them to reduce fire risk, ie, fused each cell, as well as employed temperature management to ensure long life. That's how achieved so much better range than, say, the Nissan Leaf.

I think your I-Pace will be fine. It won't burn down your house when charging. Probably. But, if you become to anxious about it, then you should probably sign it over to me and I'll do all that worrying for you.

 

[Domenick]

Yes, I understood your point. But 2 Tesla's in a week have burned up with people inside. We have to re-look at the safety systems.. How many bolts have gone up in flames, I know at least 1 Bolt had the battery pack compromised in a head on collision with no fire.

Definitely, we have to look at the safety systems, and in the Florida situation, NHTSA is doing that.
In the Switzerland crash, from what I read, the driver had quite likely died from the impact(s). I believe Swiss authorities are investigating, which is good and proper.

I don't recall hearing about any Bolts catching fire. I don't even recall a crash, but I'll do a little search and try to get up to speed on that.

 

[David Green]

Definitely, we have to look at the safety systems, and in the Florida situation, NHTSA is doing that.
In the Switzerland crash, from what I read, the driver had quite likely died from the impact(s). I believe Swiss authorities are investigating, which is good and proper.

I don't recall hearing about any Bolts catching fire. I don't even recall a crash, but I'll do a little search and try to get up to speed on that.

Here is the Link to a Bolt head on in which there was a fatality (not in the Bolt) https://www.clickondetroit.com/all-...on-us-23-near-6-mile-road-in-washtenaw-county

 

[David Green]

I can certainly see how Tesla might seem more flammable than other luxury cars right now, but I'd like to see the hard data before making that pronouncement.

I do think the Tesla/Panasonic cells are more reactive than those use by other manufacturers. Tesla decided to go with cells that have the highest energy storage potential and then packaged them to reduce fire risk, ie, fused each cell, as well as employed temperature management to ensure long life. That's how achieved so much better range than, say, the Nissan Leaf.

I think your I-Pace will be fine. It won't burn down your house when charging. Probably. But, if you become to anxious about it, then you should probably sign it over to me and I'll do all that worrying for you.

Haha! I am not worried about the house burning down as long as the family gets out safely. I doubt the Jag would catch on fire, the way the cells are in boxes it should be able to handle most situations, and not propagate to other packs of cells. but in any case both our houses have fire sprinklers which should give the family time to escape... Thats all I really care about in that case.

Tesla Batteries are indeed packaged hot, and will light up easily if they are made angry. The energy density is a trade off for safety, I think this is the reason other automakers have not followed Tesla's design on the packs. Its like having Gasoline or Diesel, actually that is a bad example, diesel is less volatile, and also contains more energy per gallon...

 

[NeilBlanchard]

David - how do you know any of this? Methinks you are just making stuff up.

If you want to avoid vehicle fires - don't drive a gasoline car.

 

[David Green]

David - how do you know any of this? Methinks you are just making stuff up.

If you want to avoid vehicle fires - don't drive a gasoline car.

I am not sure what exactly you are replying to? Tesla batteries being more energy dense then other EV makers? That is not made up, although exact statistics are not known. Tesla "seems" to have more fires the other Luxury makers or or other BEV's, that is 100% assumption, but 3 humans have burned up in Tesla cars in the last 10 days, and I do not ever remember even one story of a human buring up in modern luxury cars, do you? Tesla currently has a slew of government safety investigations ongoing, when those are completed maybe some statistics will get released? One thing is certain Elon saying a "Tesla is the safest car on the road" is at the very least misleading.

 

[Martin Williams]

Deceleration doesn't compromise the integrity of the pack. A considerable impact is needed for that.

Well, we can argue causality I suppose. A considerable impact inevitably involves rapid deceleration and that is what caused distortion of the battery pack as well as the rest of the vehicle. You certainly wouldn't damage the battery pack by hitting the brakes too hard!

I am in full agreement with you that a severe impact is needed before enough damage is done to trigger thermal runaway however.

You are wrong about gasoline cars burning, even after severe impact, though. Despite Hollywood's depiction of an impact resulting in a firebomb, this actually doesn't happen, and even a fire following the crash is rare. Those that do occur do so usually due to a damage to the electrical system causing a short circuit, heating up the conductors and melting the ignition before igniting it.

In order to stage a 'Hollywood' explosion, significant technical equipment is needed including explosives to disperse fuel in containers placed in the passenger cabin and the timed ignition of propane-air mixtures etc.

I would not be surprised to find that the probability of ICEs going on fire is pretty well unrelated to the severity of the crash after a certain point, but I think the probability of fires in battery cars would go up pretty well directly with the speed of impact.

 

[NeilBlanchard]

I am not sure what exactly you are replying to? Tesla batteries being more energy dense then other EV makers? That is not made up, although exact statistics are not known. Tesla "seems" to have more fires the other Luxury makers or or other BEV's, that is 100% assumption, but 3 humans have burned up in Tesla cars in the last 10 days, and I do not ever remember even one story of a human buring up in modern luxury cars, do you? Tesla currently has a slew of government safety investigations ongoing, when those are completed maybe some statistics will get released? One thing is certain Elon saying a "Tesla is the safest car on the road" is at the very least misleading.

Your claim that Tesla battery packs are easily ignited - is baseless.

 

[Martin Williams]

Er... Here are some Tesla cells being crushed.



I was a bit surprised how quickly they ignited. At the point when they ignited, the crushing had only just split the can. Given that the 2170 cells are bigger and contain more energy I expect them to be rather more fragile.

Incidentally, I estimated how much force you'd have to apply to a half ton of battery (500kg) whizzing along at 30 meters a second (A bit less then 70mph) in order to stop it in 100 milliseconds. This is a deceleration of 300 m/s squared - about 30 g - and the force required to do it is 150,000 Newtons.

What does a force of 150,000 Newtons imply in terms of everyday experience? Well, it is pretty near a fifteen-ton weight applied to the battery for that tenth of a second of deceleration.

If this is distributed over all the batteries equally, they might well stand it OK, but it is more likely that the cells at the front of the pack will stop much faster and the ones behind will carry on. In other words, you'll get a wave of crushing moving from front to back until all the kinetic energy is dissipated.

 

[Domenick]

You are wrong about gasoline cars burning, even after severe impact, though. Despite Hollywood's depiction of an impact resulting in a firebomb, this actually doesn't happen, and even a fire following the crash is rare. Those that do occur do so usually due to a damage to the electrical system causing a short circuit, heating up the conductors and melting the ignition before igniting it.

In order to stage a 'Hollywood' explosion, significant technical equipment is needed including explosives to disperse fuel in containers placed in the passenger cabin and the timed ignition of propane-air mixtures etc.

I would not be surprised to find that the probability of ICEs going on fire is pretty well unrelated to the severity of the crash after a certain point, but I think the probability of fires in battery cars would go up pretty well directly with the speed of impact.

ICE-powered cars certainly don't explode in real life as often as they do in the movies, but cars crash and burn, killing people. Even in luxury brands.
Here are just a few examples from a quick search using BMW, Mercedes, and Jaguar.

Two fathers watch helplessly as their families burn to death in Calif. car wreck
Two burn to death in horror M4 crash
Fiery 3-vehicle collision leaves 1 dead, another injured in Palmdale "...when the BMW they were in burst into flames after being rear-ended..."
FAMILY WIPED OUT – 3 BURN TO DEATH IN MERCEDES CRASH ON TAPPAN ZEE
http://www.chronicle.co.zw/8-die-in-horror-crash-3-burn-to-death-drunk-driving-alleged/
Two brothers die, one person critically burned in fiery crash in D.C.
Shocking photos capture aftermath of vicious fire which tore through Jaguar near Banstead "The heat from the blaze was so extreme that it caused a nearby bollard to melt"