Model S Accident/Fire

[texex91]

New AP story posted on ABC news. At least they are putting things in perspective. I guess as a result of the comments posted by "teslots" on their website.
______________________________________________________________________________________________________________________________________________________________________
The CEO of electric car company Tesla says a battery in a Model S that caught fire this week was apparently impaled by a metal object.Elon Musk gave more detail in a blog post Friday about the fire that became an Internet sensation and unsettled Tesla investors. He also defended the car's battery technology.
Musk wrote in a blog post Friday that fires are more common in conventional gas-powered vehicles.
"For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery than a large tank of highly flammable liquid," Musk wrote.
The CEO said a curved metal component was apparently the culprit in causing a Tesla to catch on fire Tuesday. He says the object's shape led to a powerful hit on the underside of the vehicle, punching a 3-inch hole through an armor plate that protects the car's bottom.
The company said the car properly contained the blaze. The driver was able to exit the highway in the Seattle suburb of Kent before flames engulfed the front of the vehicle.
Of the estimated 194,000 vehicle fires in the U.S. each year, the vast majority are in cars and trucks with gasoline or diesel engines. Electric vehicles make up less than 1 percent of the cars sold in the U.S.


Full story http://abcnews.go.com/Business/wireStory/tesla-fire-shows-electrics-face-safety-challenges-20463902

Great on a Friday evening when no one is reading anything...

 

[gameon]

Musk is also using statistics to cover his side. How many cars the age of a Tesla catches fire when hitting driving over an object? That's the question, not how many overall fires there are. Many fires are in old cars that are not maintained, or happen when a car pulls over to the side of the road and ignites the brush, or during a multicar accident or an accident involving turnover.

 

[rsquared99]

This news just in - Boeings CEO has offered to help Tesla with their battery design if Elon would like. Just kidding, sounds like the design worked just right.

 

[mep]

The blog reads mostly like a marketing piece to the masses who aren't educated about Model S design. Didn't learn anything new.

Now I must wonder...

how does

"A curved section that fell off a semi-trailer was recovered from the roadway near where the accident occurred and, according to the road crew that was on the scene, appears to be the culprit. The geometry of the object caused a powerful lever action as it went under the car, punching upward and impaling the Model S with a peak force on the order of 25 tons. Only a force of this magnitude would be strong enough to punch a 3 inch diameter hole through the quarter inch armor plate protecting the base of the vehicle."​

read like a marketing piece?

 

[jerry33]

Now I must wonder...

how does

"A curved section that fell off a semi-trailer was recovered from the roadway near where the accident occurred and, according to the road crew that was on the scene, appears to be the culprit. The geometry of the object caused a powerful lever action as it went under the car, punching upward and impaling the Model S with a peak force on the order of 25 tons. Only a force of this magnitude would be strong enough to punch a 3 inch diameter hole through the quarter inch armor plate protecting the base of the vehicle."​

read like a marketing piece?

I guess if it puts the car/company in a positive light, it's a marketing piece.

 

[bareyb]

There's going to be a few stragglers who are bummed they can't talk smack about Tesla any longer and will try anything to keep the negative from dying out. I say ignore them and they'll get bored and go away. It's time to put this behind us and revel in the good news for awhile. Tired of the naysayers. Find a new hobby and save the drama for your Mama! PEACE!

 

[RobStark]

Musk is also using statistics to cover his side. How many cars the age of a Tesla catches fire when hitting driving over an object? That's the question, not how many overall fires there are. Many fires are in old cars that are not maintained, or happen when a car pulls over to the side of the road and ignites the brush, or during a multicar accident or an accident involving turnover.

I have been googling for that information and can't find it.

Can you?

If the statistics are not compiled by the insurance industry, fire department associations, or other interested party and made available to the public then there is no such data to compare.

You use the best available data.

- - - Updated - - -

Great on a Friday evening when no one is reading anything...

People are reading less on Fri afternoon but people are always reading.

As long as it part of the narrative from now on.

 

[MikeL]

Re the email: owner's letter to Jerome G. brings joy to my heart. Talk about rising to the occasion. Just what I would expect from your average, everyday joe(Robert) Tesla owner :smile:

 

[brianman]

Not sure I read about that during my MBA program, but I can assure you Wall Street cares about backlog, reservations and closed sales--period.

"Weeding out" owner candidates means nothing.

I'm saying currently cancelled reservations is having no impact on sales. That will change someday, but it's not here yet.

 

[Ocelot]

i agree with the above.

not sure if the point has been made already, but to me the correspondence between Tesla and the owner of the car that caught fire did not add any information. I think it was likely included due to all the conspiracy talk on this forum. poor dude's car catches fire, and next thing he knows is his previous work experience is being posted on the internet and he is being called a saboteur. i think the e-mail exchange was probably included just to help the dude out, maybe even at the owners request.

i would like to expand on this a bit as i get pfq's point, and after reading the rest of the entries feel the need to comment.

the best analogy i can give is a new drug hitting the market. sure it has gone through all sorts of test and trials for safety, and there is a ton of hype around the drug, but it is only when it hits the market and has been around a few years that you really begin to get an idea of possible side-effects or saftey issues that were never picked up before. just a matter of time and scale giving better data. the drug might be the safest best out there, but really only time will tell.

stats can be skewered, and I also felt the comparison is not comparing apples to apples ( and yes i realize in this case that would be impossible). and yes I am an x-reservtion holder, and yes I am a believer that in time the saftey record will be amazing as even if there are flaws now i believe in the company to fix anything that comes up.

no-one on this board could guarentee you 100%, elon and his crew is right. i think they are, but to say with certainty more fires will not happen and a flaw found, would be inaccurate. time is a stripper, and she will reveal all.

 

[mlindner]

Isn't it f=mv^2? You can make some pretty graphic pictures if you assume the higher order variable is 0!

I registered just to correct this egregious physics. It's F = ma, or force equals mass times acceleration. You posted (sort of) the equation for kinetic energy or E_k = 1/2 * m * v^2. But yes, if you assume acceleration to be g, as in the acceleration from earth's gravity, or 9.8 m/s^2, or 32 ft/s^2, then yes you can make some pretty graphic pictures.

 

[yobigd20]

Here's one for ya:

the day this story hits the press all over the place (yesterday, or the day before, doesn't really matter) , is the same day that Tesla got awarded this patent:

http://www.faqs.org/patents/app/20130260192

Patent application title: Battery Pack Pressure Monitoring System for Thermal Event Detection


Inventors: Francisco Richard Leport (San Francisco, CA, US)
Assignees: TESLA MOTORS, INC.
IPC8 Class: AH01M1050FI
USPC Class: 429 62
Class name: Chemistry: electrical current producing apparatus, product, and process with control means responsive to battery condition sensing means temperature control
Publication date: 2013-10-03
Patent application number: 20130260192

A system for detecting thermal events, e.g., thermal runaway, within a sealed battery pack based on a characterization of monitored pressure variations within the pack is provided. The system includes at least one pressure sensor coupled to the battery pack and to a pressure monitoring system that outputs pressure data representative of the battery pack pressure over time; a system controller that analyzes the pressure data and outputs a control signal when the pressure data fits a specific curve shape; and a thermal event response subsystem that performs a preset response upon receipt of the control signal from the system controller. The system may include a secondary effect monitoring system, wherein the thermal event response subsystem performs the preset response when the pressure data fits a specific curve shape and the secondary effect is detected by the secondary effect monitoring system.

Filing Dt:03/29/2012 Publication Date: 10/03/2013. irony.

 

[brianman]

I'm genuinely interesting in knowing if this is the source of disagreement. I never claimed to have proof of anything.

Well, FWIW, I'm still looking for signs that there was actually a cascade rather than just multiple ruptures. But frankly I'm tired of playing the terminology game (and apparently other people are as well) since we clearly see things differently. Cells vs. modules for example.

"The data is consistent" with all kinds of things that aren't reality, so I prefer to focus on what the evidence supports or suggests rather than just "what it's consistent with".

So I'll just call everything I see as a Cascade(TM) and "consistent with the facts" and be done with it. Apparently, you'd prefer to do that.

I didn't say you made up facts, I said you weren't entitled to your own (at least that's what I recall). But whatever, if you want to dwell on it and be unhappy then fine. Start a "BrianMan gave me angst" thread and move it all there. I'm done with it, and based on feedback I've gotten in various ways apparently others are too.


For future reference, when I see words like "cascade" and "consistent with" I'll just ignore the post and move on. It's apparently not worth my time or effort trying to quell the drama by attempting to push the conversation to more precise and accurate terminology.

 

[Shumdit]

cars on fire - Google Search

Every car can burn. Nuff said.

Not true:
Sculpture park. Yes i know it looks like a kingswood painted gray, but it's made of cast concrete. It's Fuel economy must be awful. - Ambassador Van - Australia - WorldNomads.com

:wink::biggrin:

 

[c041v]

Just received this email (which we have already dissected 100x's over) from Tesla in mailbox--2 hours after blog post.

At least they are proactively reaching out--but they need to reach out to press, not just current owners:

FYI, I received the e-mail too, and I'm not an owner. Must just be anyone on the mailing list. I wonder if that includes the press.

I must admit though, I'm a bit curious as to how Elon arrived at the 25 tons of force calculation. If I recall my knowledge from physics;

F = ma

Meaning that there was an object of some mass (likely stationary) that was accelerated by a Model S moving along at 50 mph. Now, while I don't know exactly how fast that would cause the object to accelerate, it obviously had enough mass to get us 25 tons of force.

The second part of this is the 3 inch hole. Again, I recall a familiar equation from strength of materials;

P = F/A

Meaning that the pressure exerted was something like (Using pounds and inches);

P = (50000)/((3.14*1.5)^2)
P = 7073 Psi

Which for some reason, makes more sense to me. 25 tons of force can be equated in Hummers and Minis, but it's really the mass and the acceleration of the object itself that matters. Assuming the Tesla was moving at 50 mph when it struck the object which was stationary, that (I believe) works out to an instantaneous acceleration of 73.33 ft/s[SUP]2[/SUP]. Solving for m, I get an object weight of 682 lb. This helps me visualize the actual mechanics of what happened a lot clearer. (if my math is right)

So the car hit an ~700 lb stationary object that had a roughly 7.0 sq/in of surface area (or something close to it that, how the levering action plays into this is somewhat unclear) at 50 mph.

My textbooks haven't been cracked in a while, so somebody may want to check this.

*mlindner: I apologize if this is more egregious physics.

 

[Lump]

On the bright side, a few less sales means more loaners.

 

[texex91]

On the bright side, a few less sales means more loaners.

Sending a golf clap your way...

If only that would appease Wall Street--unfortunately as a public company sales and profit are all that matters at this point.

Sad yes, but true.

Gotta hit the numbers.

With this PR debacle it only makes it that much harder...even though we all know nothing is wrong.

 

[JohnQ]

FYI, I received the e-mail too, and I'm not an owner. Must just be anyone on the mailing list. I wonder if that includes the press.

I must admit though, I'm a bit curious as to how Elon arrived at the 25 tons of force calculation. If I recall my knowledge from physics;

F = ma

Meaning that there was an object of some mass (likely stationary) that was accelerated by a Model S moving along at 50 mph. Now, while I don't know exactly how fast that would cause the object to accelerate, it obviously had enough mass to get us 25 tons of force.

The second part of this is the 3 inch hole. Again, I recall a familiar equation from strength of materials;

P = F/A

Meaning that the pressure exerted was something like (Using pounds and inches);

P = (50000)/((3.14*1.5)^2)
P = 7073 Psi

Which for some reason, makes more sense to me. 25 tons of force can be equated in Hummers and Minis, but it's really the mass and the acceleration of the object itself that matters. Assuming the Tesla was moving at 50 mph when it struck the object which was stationary, that (I believe) works out to an instantaneous acceleration of 73.33 ft/s[SUP]2[/SUP]. Solving for m, I get an object weight of 682 lb. This helps me visualize the actual mechanics of what happened a lot clearer. (if my math is right)

So the car hit an ~700 lb stationary object that had a roughly 7.0 sq/in of surface area (or something close to it that, how the levering action plays into this is somewhat unclear) at 50 mph.

My textbooks haven't been cracked in a while, so somebody may want to check this.

*mlindner: I apologize if this is more egregious physics.

I expect that they did a quick experiment to determine how much force was necessary for a 3" object (i think that was the diameter) to puncture the battery casing. 25 tons is technically a measure of force (weight) not mass. In other words it is a mass that exerts 25 tons of force at 1 g.

Edit: to be clearer, a pound (or a ton) can be a measure of force (lbf) or mass (lbm), and are equivalent under 1g. Would be easier if they used SI units.

 

[c041v]

Would be easier if they used SI units.

I fully agree, but was trying to be conscious of the mostly American members...

 

[texex91]

Owner Of Battery Fire Tesla Model S Says Car 'Performed Very Well,' Will Buy Again