Official Tesla Model S thread

TonyWilliams said:

There's a HUGE difference in the reaction of the LEAF battery chemistry than the chemistry of the Tesla, which REQUIRES temperature control, or there would be a whole bunch more fires!!!

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What is the chemistry difference? Are Tesla battery packs really more vulnerable to fires? Why?

The LEAF and Volt have many times more fleet miles than Tesla, yet AFAIK, not a single fire caused by the battery in either vehicle other than the well publicized fire in the Volt weeks after a crash test.

What can Tesla to do prevent it? If its battery chemistry seems that they can't fix it. More protection? Fire retardant?

^^^
I don't know the details, but I was able to find http://www.mynissanleaf.com/viewtopic.php?p=259684#p259684" onclick="window.open(this.href);return false;, no thanks to Google nor Bing. Ugh... if they could only index this site better.

http://batteryuniversity.com/learn/article/types_of_lithium_ion" onclick="window.open(this.href);return false; is something on the many variants.

dm33 said:

What can Tesla to do prevent it? If its battery chemistry seems that they can't fix it. More protection? Fire retardant?

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By most accounts they have already taken extraordinary protective measures. Whether or not there is foul play involved, this is simply the law of averages catching up with a company that's caught the public's eye. Though if you do the math they're still faring better than average so far. With respect to LEAF and Volt fires, I'd be shocked if they've evaded the law of averages. I suspect their numbers are on par with everyone else's. They're just not the media darlings Tesla is so we probably never heard about them.

^ Do you mean the law of large numbers? It's not just a good idea, it's the law!

GeekEV said:

dm33 said:

What can Tesla to do prevent it? If its battery chemistry seems that they can't fix it. More protection? Fire retardant?

Click to expand...

By most accounts they have already taken extraordinary protective measures.

Click to expand...

Which accounts are those? They have impressive patents but some of them are not implemented. In another thread someone claimed there is no fire retardant between the cells. Also for the 65kWh version they could space out the cells more. The coolant is said to have a couple of issues. One: is flammable. Two, when pack is damaged leaks, and that alone is enough to cause a fire with type of cells used. Yes, a lot of text with out references.

LTLFTcomposite said:

^ Do you mean the law of large numbers? It's not just a good idea, it's the law!

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Still - you gotta love the irony. Thousands & thousands of ICE cars catch fire during accidents per week ... and if that point is raised? You'd hear, "get over it". But drive a Tesla thru a house at high speed, and through a concrete wall (never mind the drive runs away from it) ... it it catches fire, all hell breaks loose. Never mind the fact that ICE fires happen from other means (leaky fuel lines, etc) ya gotta love sensationalism.
.

dm33 said:

What is the chemistry difference?

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Tesla = nickel-cobalt-aluminium ('NCA') lithium-ion (standard Panasonic consumer cells), good on life, storage and power, a bit higher on cost.

Most others (Nissan/Renault/GM) = lithium manganese oxide ('LMO'), which is a good 'all-rounder' chemistry (or 'mediocre' at everything, if you are being disparaging) and, of course, cheaper than most others.

I think I read Fisker and some Ford products are using lithium phosphate, good on safety, but don't hold me to that.

Domestic (Japan) market MiEVs are now getting lithium titanate, which is the best for longevity but is expensive and lower energy storage.

Lithium titanate would be my choice if I wanted to keep a car for 20 years and I could afford it, followed by NCA though it is considered one of the least safe chemistries.[ :? ]

If I was choosing on cost and I was only keeping the car for 5 years, I'd be happy with LMO (which is just as well, as with my budgets, and current offerings, I have no choice in the matter!).

hill said:

Still - you gotta love the irony. Thousands & thousands of ICE cars catch fire during accidents per week ... and if that point is raised? You'd hear, "get over it". But drive a Tesla thru a house at high speed, and through a concrete wall (never mind the drive runs away from it) ... it it catches fire, all hell breaks loose. Never mind the fact that ICE fires happen from other means (leaky fuel lines, etc) ya gotta love sensationalism.
.

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I've cited those stats in conversations. As an EVangenlist, I conveniently neglect that in all likelihood those numbers don't take into account that we are comparing nearly new EVs to a much older average population of ICE vehicles, Dick Van Dyke's new Jag notwithstanding.

From 2008 to 2010, an estimated 194,000 highway
vehicle fires occurred in the United States each year
resulting in an annual average of approximately 300
deaths, 1,250 injuries and $1.1 billion in property loss.


http://www.usfa.fema.gov/statistics/reports/vehicles.shtm" onclick="window.open(this.href);return false;


Approximately one in seven fires responded to by fire departments across the nation is a highway vehicle fire. This does not include the tens of thousands of fire department responses to highway vehicle accident sites.
Unintentional action (32 percent) was the leading cause of highway vehicle fires.
Eighty-six percent of highway vehicle fires occurred in passenger vehicles.
Sixty-one percent of highway vehicle fires and 35 percent of fatal highway vehicle fires originated in the engine, running gear, or wheel area of the vehicle.
The leading factor contributing to the ignition of highway vehicle fires was mechanical failure (44 percent).
Insulation around electrical wiring (28 percent) and flammable liquids in the engine area (18 percent) were the most common items first ignited in highway vehicle fires.

Repost from me:

I hope this is a wakeup call for the entire aviation industry (the Boeing 787 battery fires) that these new generation batteries deserve particular handling and safety protocols that didn't exist previously. There are many reasons that Nissan picked the current chemistry battery in the LEAF, and safety was a big one.

For reference, the batteries in my Rav4 and Tesla's have a GIGANTIC uptick in explosiveness.

Charles Whalen, from October 2010 on the GM Volt forum:

http://gm-volt.com/forum/showthread.php?5243-Volt-thermal-management-system-temperature-band&p=43732#post43732" onclick="window.open(this.href);return false;

"LiMn2O4 is a safer chemistry [the LEAF battery - Tony] than LiFePO4. When they go into thermal runaway, LiMn2O4 reaches a peak combustion rate of 2.5C/min, while LiFePO4 reaches a peak combustion rate of 3.4C/min. Contrast those to the combustion rates of the batteries that Tesla uses -- in the Roadster, LiCoO2 reaches a peak combustion rate of 360C/min, and in the Model S, LiNi.8Co.15Al.05O2 reaches a peak combustion rate of 280C/min..."

"LiCoO2 and LiNi.8Co.15Al.05O2 are so unsafe -- the most volatile of all the lithium chemistries, by an order of magnitude of more than 100X (I gave the combustion rates above) over the two safest lithium chemistries, LiMn2O4 and LiFePO4 -- that no large, established automaker could afford to take that kind of risk, to use either of those two chemistries (LiCoO2 or LiNi.8Co.15Al.05O2) in a mass-market commercial EV. A large OEM like GM or Ford has just too much at stake and too much to lose to take a risk like that. Only a struggling small start-up like Tesla, which is an extremely risky venture to begin with, on the perilous edge of survival, can afford to take an enormous risk like that."

I think that's someone rather egging for an argument, such provocative language.

The Panasonic NCA cells have been developed with automotive EV use as a target end usage. Safety will therefore have been considered. Tesla may be a small start up, but Panasonic?!? A company with 300,000 staff and a turnover of $100 billion? Panasonic will have their reputation to consider too.

Any Li tech can get out of hand when cell plates end up shorting, or going over volts and plating with elemental Li, electrolyte chemistry or not. I'm not saying there aren't safer technologies, but if you want higher energy density and power output then you have to go for a more reactive chemistry. You can't have higher performance with lower reactivity!

I'd have more concerns about the battery pack topology and whether the packs are paralleled in such a way that defects (from faults or accidents) can cause reverse currents. In Tesla multi-cell tech, there will be a large number of paralleled cells, unlike the large-format packs in the Leaf (in common with most others) where each module is 4 packs consisting of 2 series packs each in parallel with the other two series packs.

There is also another question of whether the chemistry is fit to be managed with water. I don't know much about LMO in that situation - if an LMO battery was in flames then can fire crews use standard water techniques to deal with it? It is a risk/management thing if you choose to go with a more likely failure that you can more easily deal with, than a less likely outcome but that you have no way to deal with it. The former may be preferred over the latter.

But, in any case, the statistics do not [yet] suggest Tesla are out of the norm on vehicle fire rates. They can't yet claim to be the least likely to catch fire (!) given recent events, but I've no particular reason to yet presume they are the worst make either.

If the danger is the battery pack being damaged when the car runs over an object, they should look at something that detects such a collision is imminent and instantly maxes the air suspension ride height.

If that's not enough, maybe they can patent something like this:

Jump forward to 1:40....

[youtube]http://www.youtube.com/watch?v=eSi6J-QK1lw[/youtube]

^ That's awesome! Of course if the system guesses wrong and it's a larger object, or there is another object just beyond it, the car would impale itself on it. Not sure if that is better or worse.

So if a car is headed for a big hunk of metal on the road, what are the options?

- instantly jack up the suspension and hope to clear it
- try to jump over the obstruction
- deploy a cow catcher that could possibly deflect the object from going under the car
- just go ahead and hit the object, let come what may, safely exit the vehicle before any fire really gets going and let the insurance company and/or collision shop deal with the aftermath of such an accident.

The last option is probably the best one, although some degree of the first two could possibly be done in software on the model S.

DanCar said:

GeekEV said:

dm33 said:

What can Tesla to do prevent it? If its battery chemistry seems that they can't fix it. More protection? Fire retardant?

Click to expand...

By most accounts they have already taken extraordinary protective measures.

Click to expand...

Which accounts are those? They have impressive patents but some of them are not implemented. In another thread someone claimed there is no fire retardant between the cells. Also for the 65kWh version they could space out the cells more. The coolant is said to have a couple of issues. One: is flammable. Two, when pack is damaged leaks, and that alone is enough to cause a fire with type of cells used. Yes, a lot of text with out references.

Click to expand...

These: http://www.teslamotorsclub.com/showthread.php/13121-Inside-the-Tesla-battery-pack" onclick="window.open(this.href);return false;

donald said:

There is also another question of whether the chemistry is fit to be managed with water. I don't know much about LMO in that situation - if an LMO battery was in flames then can fire crews use standard water techniques to deal with it?

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http://www.evsafetytraining.org/resources/auto-manufacturer-resources/tesla-motors.aspx" onclick="window.open(this.href);return false;
http://www.teslamotors.com/firstresponders" onclick="window.open(this.href);return false;

FIREFIGHTING
Extinguish small fires, that do not involve the high voltage battery, using a CO2 or ABC extinguisher.

During overhaul, do not make contact with any high voltage component. Always use insulated tools for overhaul. Stored gas inflation cylinders, gas struts, and other components can BLEVE (Boiling Liquid Expanding Vapor Explosion) in extreme temperatures. Perform an adequate “knock down” on the fire before entering the incident’s “hot zone.”

If the high voltage battery becomes involved in fire or is bent, twisted, damaged, or breached in any way, or if you suspect that the battery is heating, use large amounts of water to cool the battery. DO NOT extinguish fire with a small amount of water. Always establish or request an additional water supply.

Battery fires can take up to 24 hours to fully extinguish. Consider allowing the vehicle to burn while protecting exposures.

Use a thermal imaging camera to ensure the high voltage battery is completely cooled before leaving the incident. If a thermal imaging camera is not available, you must monitor the battery for re-ignition. Smoke indicates that the battery is still heating. Do not release the vehicle to second responders until there has been no sign of smoke from the battery for at least one hour.

Always advise second responders (law enforcement, tow personnel) that there is a risk of the battery re-igniting. After a Model S has been involved in a submersion, fire, or a collision that has compromised the high voltage battery, always store it in an open area with no exposures within 50 feet.

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http://www.teslamotors.com/blog/model-s-fire" onclick="window.open(this.href);return false;

When the fire department arrived, they observed standard procedure, which was to gain access to the source of the fire by puncturing holes in the top of the battery's protective metal plate and applying water. For the Model S lithium-ion battery, it was correct to apply water (vs. dry chemical extinguisher), but not to puncture the metal firewall, as the newly created holes allowed the flames to then vent upwards into the front trunk section of the Model S. Nonetheless, a combination of water followed by dry chemical extinguisher quickly brought the fire to an end.

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As usual, Charles Whalen's old quote in Tony's repost states the issue clearly. AFAIA, Panasonic didn't develop the 18650 NCA cells with EVs as an intended end use, but I could be wrong. OTOH, Tesla uses a modified form of the cells, which IIRR removed one of the safety elements to simplify them and reduce cost, but then added control and cooling hardware.

Found this, "A General Discussion of Lithium-Ion Battery Safety",

http://www.electrochem.org/dl/interface/sum/sum12/sum12_p037_044.pdf" onclick="window.open(this.href);return false;

which includes a photo of a hacked Prius (converted to plug-in) which burned due to a battery thermal runaway. The only area of disagreement with Whalen is that this report says that LiFePO4 is safer from thermal runaway than LiMn2O4, but it may be that this claim (which agrees with info I've found elsewhere) and Whalen are talking about two different things. Anyway, it talks about all the chemistries currently in use, coating etc.

GeekEV said:

DanCar said:

GeekEV said:

By most accounts they have already taken extraordinary protective measures.

Click to expand...

Which accounts are those? They have impressive patents but some of them are not implemented. In another thread someone claimed there is no fire retardant between the cells. Also for the 65kWh version they could space out the cells more. The coolant is said to have a couple of issues. One: is flammable. Two, when pack is damaged leaks, and that alone is enough to cause a fire with type of cells used. Yes, a lot of text with out references.

Click to expand...

These: http://www.teslamotorsclub.com/showthread.php/13121-Inside-the-Tesla-battery-pack" onclick="window.open(this.href);return false;

Click to expand...

Yep, that post suggests all of my comments are accurate and there is much more than can do for safety.

DanCar said:

GeekEV said:

These: http://www.teslamotorsclub.com/showthread.php/13121-Inside-the-Tesla-battery-pack" onclick="window.open(this.href);return false;

Click to expand...

Yep, that post suggests all of my comments are accurate and there is much more than can do for safety.

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I won't be at all surprised if Tesla has to develop and install a steel protective plate under the battery, because I don't think the insurance companies will be happy if hitting road debris causes totaling in a large number of cases, instead of say $5-$10k of repairs. GM took a similar step after the Volt fire, even though the need for it was probably a lot less in that case.

GRA said:

AFAIA, Panasonic didn't develop the 18650 NCA cells with EVs as an intended end use, but I could be wrong.

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Why not just call my comment and ask for a source, rather than throw in guess that confuse the thread?

See;
http://panasonic.co.jp/corp/news/official.data/data.dir/en091225-3/en091225-3.html" onclick="window.open(this.href);return false;