Tesla on Fire
 

Local to the Seattle area (Kent. WA)...

Batteries Burned In Tesla Model S Fire, Firefighters Say

http://forums.pelicanparts.com/uploa...1380817708.jpg

Weird. AP story

Tesla claims the fire was caused by a large metallic object that directly hit one of the battery pack's modules.

Apparently no other gas powered cars caught fire from the "large metallic object" in the HOV lanes . .. which hasn't been found.

Gas powered cars catch on fire all the time. Ask any fireman. It is not newsworthy. Like another car crash. If a airplane lands off filed it is headline news.

That’s not really true --- Lithium Ion battery fires are more dangerous than conventional gasoline fires. It is a big deal.

lithium battery fires shouldn’t be treated like common fires. The burn characteristics and toxic by-product release components are different. Once a Li+ battery catches fire you will be hard pressed to stop the fire. Usually it will need to burn itself out --- that means you typically can’t extinguish the Li+ battery fire by covering the burning battery with dry chemicals or halon. At that point it’s too late and thermal runaway has started.
Lithium batteries are capable of spontaneous ignition and subsequent explosion due to overheating. Overheating may be caused by electrical shorting, rapid discharge, overcharging, manufacturer defect, poor design, or mechanical damage. In the case of an auto accident, it’s most likely mechanical damage.
Overheating results in thermal runaway, which is a reaction within the battery causing internal temperature and pressure to rise at a quicker rate then can be dissipated. When a battery goes into thermal runaway, the thermal propagation creates a chain reaction. The fire may be a progressive burn-off or one that is explosive. Both of these types of thermal events, as well as their negative by-products (shrapnel, molten metal, burning electrolytes, and other matter) are really dangerous.
Once one battery cell goes into thermal runaway, it produces enough heat to cause adjacent battery cells to also go into thermal runaway. This produces a fire that repeatedly flares up as each battery cell in turn ruptures and releases its contents. The result is the release of flammable electrolyte from the battery and, can cause the release of molten burning lithium. It’s a big issue that these fires can’t be treated like “normal” fires and require specific training, and extinguishing techniques.

Tesla stock dropped about 5% after the fire news went viral.

Down 19 points now, was 24.

This company/car is so polarizing. God forbid anybody try to innovate or do something different in this country anymore. Pretty accurate article on what happened and the subsequent sensationalist responses:

Surprise, Cars Sometimes Catch Fire When Crashed! Why Everyone Needs To Take A Breath On Tesla

Tesla is renowned for the safety of its lithium batteries; GM and others have programs to reverse engineer the Tesla technology.

Amir is correct about the mindless Teslahate - worse than the regular eHaters.

You are presuming that hundreds of pounds of burning/exploding Alkali metal batteries with flammable electrolyte is either risk neutral or lower risk than a vehicle with 20 gal tank of gas (~120 lbs) that catches fire. We have the experience with gasoline vehicle fires to bound their risk.

I don't think enough data has been collected to assess either the normalized frequency of occurance or the severity of consequences if there is a fire --- comparing Li+ batteries to gasoline or diesel.

Defending innovation is laudable, but one should seek to understand collateral risks that are associated with the innovation. I think the jury is still out for Li+ vehicle fires.

dunno what is up with that

perhaps the car shows impact damage?

presumably it would travel some distance before stopping, so it might be hard to find an object that hit it - esp. if they did not shut down the entire hwy for an extended time

anyway, we will see if there are > 1 example of this

it's a great day to buy tesla!

if i had some money sitting around in my account, it'd buy another couple grand.

Yeah, like a magnesium case from an old 911 never burned and got worse when adding water.......

Crashed! ???

Running over road debris now equals "Crashed!"

or are you saying that this IS the subsequent sensationalist response?

Tesla's financials: A peek under the hood - The Globe and Mail

It was Ironman. I knew it!

I would like to see the actual damage from the "presumably rather large metal object." From what I have read from the "accident" scene, there was no visible damage to the car near the placement of the battery.

BTW: I am not anti-Telsa. I actually like the car (prefer the sports car model like the Lotus), but I would still like to know the cause.

Aren't the Tesla batteries just big stalks of off-the-shelf lithium batteries. I don't think they make their own batteries, they just collate them?

they are off the laptop batteries but they have some secret way they make up the battery pack

GM has a whole team set up to figure it out

yes, there are certain unique dangers to Li battery fires (esp. on aircraft...) - but the compartment is supposed to be sealed - maybe it was CF and burned?

we need to see if there is a pattern of such events (the govt. would do that via NHTSA if it isn't shut down)

There are lots of design considerations to package Li+ cells into a battery. each cell is pressurized and contains fammable electrolyte. If you over charge a cell, it will overpressurize and bad things happen. If you over discharge a cell a "voltage crash" occurs, and under certain circumstances the cells can self-reverse bias --- again bad things happen. Also, over a set of charge/discharge cycles, the cells in a battery become divergent in their charge state and don't equally charge. Therefore, you need to design cell balance electronics that will "Bypass" stronger cells while the "weak sisters" catch up. If you have a reliability issue with your charge control electronics, bad things will happen.

While all this is in-play you need a thermal management system designed into the battery packaging to maintain safe thermal operating limits.

Li+ battery design may not fully qualify as "rocket science", but it's way harder that just buying a stack of cells and bolting them under the hood of a car. There is tons of $$$ being poured into Li+ battery technology. Technology maturity is middle of the road, especially in applications where the engineers are trying to wring out maximum energy/kg.

Everyone should applaud automotive companies that encourage their engineers and designers to really innovate without the fear of failure, Tesla sounds like this type of company.

Technology moves on very quickly, its unstoppable and the only way to gain real knowledge is to get on with it. At some stage the research, talking, and yet more talking has to take 2nd stage to just getting on with it so as to gain real world experience.

If we waited for GM, Ford or Chevorlet to push forward the technology of cars everyone would still be driving pick up trucks that are only good at driving in a straight line.

With any new technology comes risk and yes the risks need to be assessed but no technology is risk free so risks have to be taken. One Tesla fire doesn't sound like they didn't didn't assess the risks well enough. I'm sure they will gain much more knowledge from sifting through the remains than they would still testing in the lab.

Yes, hitting a metal object is crashing into a metal object.

Or are you saying you don't know what the meaning of crashed is?