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Discussion in 'Tesla' started by David Green, May 14, 2018.
This looks terrible...
I will risk Pushmi's wrath by pointing out that we are now at four out of five fatal accidents involving fires.
Man, this is not funny... it looks like this one could be similar to the one in CA where the car struck the interchange barrier... I feel sad for the families of these people.
At the risk of sounding like a Tesla apologist, I would point out that vehicles crash and catch fire on a daily basis the world over.
Man killed in fiery crash on S.R. 55 in Moore County
'Something terrible:' Fiery motorcyle crash shuts down Florida highway for hours.
One dead, six injured, in fiery Monroe County crash
Police ID Man, Woman Who Died in Fiery Inglewood Crash
A quick web search gave me these 4 recent instances as the top results. There were many more recent fiery crashes below these.
None of them were national news because this happens all the time. So, why is a Tesla crash news? Good question. I'm glad you asked.
There are probably a number of different reasons. One, it's a relatively new company and it's using newer technology to store energy (lithium batteries). The also have one of the most advanced driver assist packages out there, which was rolled out with too few safeguards, ie, people able to get in the back seat, long intervals between requests for driver confirmation (though those have been significantly beefed up).
There is also a sizable community with a strong financial interest in Tesla's failure, or at least, a falling of its stock price. They tend to flock around reporters on the automotive/Tesla beat on social media in an attempt to Pinto the company's cars. I'd like to think that's not really a successful strategy, but watching Dana Hull's Twitter feed lately has been, um, interesting.
And, for whatever reason, there are a number of writers who don't like the idea of electric vehicles, or Elon Musk, or his company.
There is also the fact that Tesla is very "clicky." A story with Tesla in the headline gets you a lot of hits, so you have people looking for any reason to stick Tesla in a headline.
Agree, but this is 3 Tesla fatalities by incineration in less then a week, and 2 other accidents that are highly suspicious of the automatic driving system. Many Luxury cars have no fatalities recorded... Tesla's safety record is very much in question... Elon's claims about the safest cars are purely false.
Humour wasn't intended. It is becoming increasingly obvious that if you damage the battery you are going to have a very bad fire on your hands. Yes, fires happen with petrol cars too, but there are far more of them being driven about. The best estimated I can find for fires following bad accidents in ICEs is about 3%. Teslas seem to be at around 80%
I don't know what the stats are for luxury car fatalities by driven mile. It is nuts that these fatalities are lumped together so closely in time, though.
I would like to see some nice dispassionate, unbiased data on auto safety. I certainly think Elon is biased towards his own vehicles, naturally.
They only keep data on cars with over 100K sales, there are several luxury cars that have never had a fatalities... Audi A6, BMW 535IS, and 535XI, I was surprised to see the Mazda CX9 on the list...
Fires in Petrol cars happen, but many of the ones I have seen were not related to the fuel... Interior, cigarette, oil leaks, transmission fluid causes lots of fires, electrical, etc... The lady that cleans our house had her ford t-bird burn up in her driveway and it had been sitting overnight on its own. Later she learned she had bad ignition wiring that ford knew about, but did not recall until a couple years later.
I had a close call myself, I had my truck in for service and had the dealer install a new fuel filter, I then drove it over the mountains to our cabin, and had noticed the fuel economy did not seem as good as usual. When I arrived at the cabin there was smoke/steam coming from under the hood, and I could smell strong diesel smell. I jumped out and opened the hood, and the fuel out of the filter had been leaking right across the turbocharger, and running down the exhaust and then dripping off under the truck. I was like wow.. If this was petrol car, would be gone, thankfully diesel is somewhat more forgiving.
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)
I suspect people who buy large expensive cars drive them rather more carefully than people who buy cheap runabouts, which makes figures like this hard to use in comparisons of safety. I suspect the demographics of Tesla drivers tends to the older and wealthier sector of the population. It is not the car that is more likely to cause a crash, but the sort of people who drive them.
I think there are two questions about Tesla which need to be answered. The first is whether the autopilot can be trusted to drive safely under all conditions and the second is whether - when a serious collision takes place - Teslas are as safe as cars powered by petrol.
Tesla themselves have answered the first question themselves by pointing out that the vehicle is not guaranteed to stop if something stationary is revealed by a car ahead of them changing lanes to avoid it. The answer is therefore 'no'.
As to the second question, there is probably not enough evidence to say for sure yet, but so far it is not looking good. It seems to me that the battery packs - due to their size and density - are likely to suffer severe deformation due to rapid deceleration, and this is likely to cause thermal runaway. A damaged cell (or cells) experiencing internal short-circuiting is likely to overheat. The fuse will offer no protection to this, and the heat will damage adjacent cells.
There is a wealth of experience of severe crashes in petrol cars and it appears that fires from crashes are rare. Petrol tanks are relatively light and will not generally leak petrol unless pierced by debris. Even then, a fire is not likely without a source of ignition and that's petty unlikely. Perceptions are distorted by Movies and TV where a crash is normally shown as resulting in a fireball! Years ago I attended a lecture from a forensic scientist who poured scorn on this and other common movie tropes. In particular, he demonstrated the impossibility of igniting petrol with a lighted cigarette by sticking one into a small beaker of petrol in front of the audience, which - almost to a man - flinched as he did so!
Perhaps Tesla should try inflicting distortion on their battery packs to find out how likely a fire is when they are crushed and the question can be answered to everyone's satisfaction.
Answer: No. Autopilot is an advanced driver-assistance systems (ADAS), not a full self-driving system. It, like ADAS systems from other manufacturers, can not drive safely under all conditions.
No. This does not happen. Fires happens when an individual cell is pierced or otherwise has its physical integrity compromised. They can't be made to catch fire from rapid deceleration.
Gasoline vapour is typically what ignites, and sometimes just takes a spark from ordinary static electricity to create an event. If you stick a cigarette in gasoline it will extinguish. Had he held the beaker beneath the lit cigarette, it would have likely started burning the vapour coming off the gasoline, spreading afterward to the gasoline itself. As I noted above, a simple web search found a large number of fires in crashes. Now, this may only happen in a small percentage of crashes, but it's not a rare event.
"No. This does not happen. Fires happens when an individual cell is pierced or otherwise has its physical integrity compromised. They can't be made to catch fire from rapid deceleration."
Lithium batteries do not always need to suffer physical damage to catch fire, 2 Tesla's that I know of have burned while supercharging, and one other while charging at home, of course Tesla quickly swept these under the carpet, and no explanation was released, there was also a new Model S in France on a test drive that caught fire and burned up. These are just a few examples of I am sure many more that have not gotten reported by the media. So the batteries do not always need physical damage to burn, When Tesla vehicles are in devastating accidents it might be arguable that the fire risk is higher then ICE, but there is simply not enough available data to show one way or the other.
There may be other reasons for Teslas to catch fire, but certainly distortion of the battery pack would be very likely to cause internal shorting of one or more of the cells, and there is no reason for them to behave any differently from applying an external dead short to the cell. It will heat up, gasses will be produced and the case will rupture.
Amongst the various lunacies that one comes across on the internet, I encountered this fellow who seems to get his kicks by crushing things. The dramatic effects of crushing Lithium batteries are interesting to say the least. What a pity he didn't have some Tesla ones to crush. They might have proved much better than these.
That is cool... I have RC airplanes of varying sizes that all use LIPO batteries, I have had a few charging mishaps, and plane crash fires. When my friends come over to my shop they always ask why I charge the batteries inside of cinder blocks... Thats why... Get one overcharged, and they are downright explosive.
I am paranoid about small ones about the house and keep a careful check on them, where they are etc.
The pressure to improve energy density has pushed the technology well against the envelope as regards safety in my opinion.
Distorting the battery pack is not something that happens easily. Example: side pole test with Model 3. Battery actually adds a lot of side impact strength , doesn't distort and/or catch on fire.