Official Tesla Model S thread

[surfingslovak]

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

Charles Whalen has been right in so many things. He was familiar with the capacity loss problem Nissan historically had with their packs, among other things. While your posts appear to be well-articulated and well-informed, I have struggled with their content and with your intentions on numerous occasions. The great debate you felt was needed about Nissan's unfortunate use of the term "trickle charging" would be a good example. In my humble opinion, it's not Charles who is asking to be included on an ignore list, if you catch my drift.

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.

No, the statistics already points to Tesla's battery technology having a significantly greater risk of fires than what the LEAF or the Volt are using. There is only one Volt fire, which has been reported. In a vehicle that was crash tested and left stored against manufacturer recommendations for three weeks before the fire started. No fires have been reported for the LEAF anywhere. Between these two vehicles, they shipped probably ten times the volume of the Model S and have about ten times more fleet miles with no fire incident.

There have been severe accidents involving LEAFs and Volts. One of the ActiveE drivers was involved in a very serious accident, which left the front battery deformed and with a gaping 8-inch hole from hitting a metallic object. The car did not catch fire.

 

[donald]

The great debate you felt was needed about Nissan's unfortunate use of the term "trickle charging" would be a good example. ... the statistics already points to Tesla's battery technology having a significantly greater risk of fires than what the LEAF or the Volt are using.

(Well, I expressed my ignorance of Nissan's new usage for the term, and I was corrected on it. We should seek to learn, and if I am the clown on occasions in pursuit of that goal, then I'd say it's not a high price to pay so long as we learn and move on.)

I'm not defending Tesla and their choice of battery chemistry, I agree they have their own argument to make on the matter against some articulate arguments. I just don't think three events yet show anything that can be relied on in statistics when such events are not uncommon with other makes. though I do agree that there appears to be a particular vulnerability of the battery sandwich ahead of the front bulkhead of the monocoque, where there would be a sudden change in mechanical stiffness (often associated with mechanical failure sites). In combination with the particular tech, then I'd agree there are potential issues to keep an eye out for.

 

[LTLFTcomposite]

I won't be at all surprised if Tesla has to develop and install a steel protective plate under the battery

I saw a message board post there is a 3/4" steel plate on the underside of the battery. That doesn't right, wouldn't that weigh a ton? Does anyone know what it does have?

One problem with increasing the armor is that would be seen as a safety thing, admitting it's a problem. They could find themselves in a costly recall situation they don't have the resources to contain.

 

[TomMoloughney]

I won't be at all surprised if Tesla has to develop and install a steel protective plate under the battery

I saw a message board post there is a 3/4" steel plate on the underside of the battery. That doesn't right, wouldn't that weigh a ton? Does anyone know what it does have?

One problem with increasing the armor is that would be seen as a safety thing, admitting it's a problem. They could find themselves in a costly recall situation they don't have the resources to contain.

It's actually 1/4" and it's aluminum.

 

[DaveEV]

Charles Whalen, from about 2009 I think

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

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.

LiFe is more resistant to thermal runaway (requires higher activation temperature), but once ignited, LiMn burns slower.

 

[KJD]

How about building a box out of sheet metal that is paper thin and filling it with 20 gallons of highly flammable liquid. Now we all know that is perfectly safe right ?

NOT!!!

 

[ERG4ALL]

I am reminded of the Ford Crown Victoria that had the propensity to catch fire when hit from the rear hard enough to rupture the gas tank. Those didn't seem to get near the attention that Tesla is receiving. It took several fires before the issue was addressed and changes made.

I do wonder if some sort of barrier could be installed, perhaps like a front facia that would move the objects to the side or have the car just grind to a halt before it would allow the car to travel over the object and get to the battery.

I test drove a Tesla S performance model on Thursday. It is really impressive. The Tesla associate invited me to floor the accelerator when I reached 15 mph. It was amazing. In the matter of a few seconds we were doing 58 mph, and that was with 5 people on board. I was a bit surprised that the interior in the back seat really didn't seem any bigger than the rear seat of our LEAF although it may have been marginally so. The storage areas are huge. You really could go cross country easily once the superchargers are installed.

The problem is that with the options we would need, the regular 85 kWh model would cost $82,500 before tax credit. On top of that AZ still charges sales tax so the purchase would be around $90 K. I think that Tesla, out of necessity, will keep the price high as long as it is shouldering the cost of all of the superchargers that they intend to install throughout the country. I compared that with the many trips we could take over the next several years and have decided that I'll re-up for another LEAF lease. However, just to see if we are destined to have a Tesla, I bought five lottery tickets yesterday.

 

[TonyWilliams]

How about building a box out of sheet metal that is paper thin and filling it with 20 gallons of highly flammable liquid. Now we all know that is perfectly safe right ?

NOT!!!

They are made out of even cheaper plastic now. Has anybody seen what just generic static electricity can do to a tank full of gasoline?

 

[donald]

Has anybody seen what just generic static electricity can do to a tank full of gasoline?

It's pretty safe when it's full, providing the tank doesn't rupture. It is when it is half empty and if circumstances permit a mix of air and vapour to form above the fuel.

 

[derkraut]

How about building a box out of sheet metal that is paper thin and filling it with 20 gallons of highly flammable liquid. Now we all know that is perfectly safe right ?


NOT!!!

+1. I really think this issue of fires/electric cars has been blown all out of proportion. I surely wouldn't feel comfortable running over a hitch (or other large metal object) and puncturing the fuel tank on my ICE vehicle.

 

[Randy]

I think that Tesla, out of necessity, will keep the price high as long as it is shouldering the cost of all of the superchargers that they intend to install throughout the country.

If your factory is at full production and every car is immediately sold, the price of your car is ___________

a. Too high
b. Too low
c. Just right

The answer is (b). That's why they've raised the price 15-20% on well-equipped Model S cars since earlier this year...And they're still selling every single car coming off the line without reducing production...

 

[DaveinOlyWA]

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!!!

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?

"intent of purpose" is why. Tesla uses batteries designed for laptops...stationary laptops for the most part or ones that will probably never exceed 10 mph.

Nissan uses batteries designed for cars. ones that are designed to be slung around on this Earth at up to 100 mph and SURVIVE, but lets forget chemistry right now.

there are a LOT of flammable liquids in a car so removing gasoline only removes a very small percentage of fire causes. Tesla using a very large footprint for their pack is a mistake.

take a target that is oooh say 4 feet by 8 feet (we could use the "barn door" analogy here!) verses a target is what?? 14 inches by 24 inches times 3. (about 7 sq feet)

then start shooting. unless the targets are very close, the Tesla pack will have more bullet holes. PERIOD. it is simply MUCH more area to protect.

The Nissan pack also has the advantage in that a large portion of the packs under the rear seats are within the frame virtually eliminating damage from all directions except the one from directly beneath the car BUT

the LEAF pack is in the back, so possible damage from beneath the car must somehow avoid the front of the car...

so it goes on and on. there are actually a LOT of possible reasons why Tesla's pack is more dangerous

 

[donald]

Tesla uses batteries designed for laptops...stationary laptops for the most part or ones that will probably never exceed 10 mph.

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

 

[DaveinOlyWA]

Tesla uses batteries designed for laptops...stationary laptops for the most part or ones that will probably never exceed 10 mph.

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

I suspected ongoing improvements in stability and safety would be part of any automotive platform and great job addressing one point I presented!

so the other points?

 

[donald]

so the other points?

I'm not arguing for any position, here. Your points seem reasonable observations to me.

 

[GRA]

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

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;

Thanks for that, although I don't believe Tesla is using those cells yet. IIRC, they're still using the older 3.1Ah (min 2.9Ah) NCR18650A cells, modified for the S. I've seen it before, but can't now find the page on which Panasonic lists the specs of all their 18650s. I expect Tesla will upgrade to either the 3.4 or 4.0 Ah cells at some point - see the discussion here:

http://www.teslamotors.com/it_IT/forum/forums/model-s-going-use-new-version-panasonic-18650-series-battery" onclick="window.open(this.href);return false;

And here's a topic discussing the (patented) changes Tesla made to the battery design, including deleting some safety features:

http://www.teslamotorsclub.com/showthread.php/17456-Amazing-Core-Tesla-Battery-IP-18650-Cell" onclick="window.open(this.href);return false;

 

[scottf200]

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

November 9, 2013
From a Model S owner in Tennessee
By Juris Shibayama, MD

I was driving home from work on the interstate in the right lane at approximately 70 miles per hour, following a truck. In the middle of the lane, there was a rusty three-pronged trailer hitch that was sticking up with the ball up in the air. The truck in front of me cleared the object. I did not have enough time to swerve to avoid the hitch, and it went below my car. I felt a firm "thud" as the hitch struck the bottom of the car, and it felt as though it even lifted the car up in the air. My assistant later found a gouge in the tarmac where the item scraped into the road. Somewhat shaken, I continued to drive.

About 30-45 seconds later, there was a warning on the dashboard display saying, "Car needs service. Car may not restart." I continued to drive, hoping to get home. About one minute later, the message on the dashboard display read, "Please pull over safely. Car is shutting down." I was able to fully control the car the entire time and safely pulled off the left shoulder on the side of the road. I got out of the car, and started to get all my belongings out. About 5-10 seconds after getting out of the car, smoke started to come from the front underbody of the car. I walked away from the vehicle to a distance of about 100 yards. More smoke started to come out of the bottom of the car, and about two minutes after I walked away, the front of the car caught on fire.

I am thankful to God that I was totally uninjured in any way from this impact. Had I not been in a Tesla, that object could have punched through the floor and caused me serious harm. From the time of impact of the object until the time the car caught fire was about five minutes. During this time, the car warned me that it was damaged and instructed me to pull over. I never felt as though I was in any imminent danger. While driving after I hit the object until I pulled over, the car performed perfectly, and it was a totally controlled situation. There was never a point at which I was anywhere even close to any flames.

The firemen arrived promptly and applied water to the flames. They were about to pry open the doors, so I pressed my key button and the handles presented and everything worked even though the front of the car was on fire. No flames ever reached the cabin, and nothing inside was damaged. I was even able to get my papers and pens out of the glove compartment.

This experience does not in any way make me think that the Tesla Model S is an unsafe car. I would buy another one in a heartbeat.

Juris Shibayama, MD

 

[Berlino]

I felt a firm "thud" as the hitch struck the bottom of the car, and it felt as though it even lifted the car up in the air. My assistant later found a gouge in the tarmac where the item scraped into the road. Somewhat shaken, I continued to drive.

Wouldn't most people, as a precaution, stop to check for damage drive after such an impact?

About 30-45 seconds later, there was a warning on the dashboard display saying, "Car needs service. Car may not restart." I continued to drive

What will it take to get him to pull over?

About one minute later, the message on the dashboard display read, "Please pull over safely. Car is shutting down.

OK, as long as he's specifically told to pull over, he will.

I was even able to get my papers and pens out of the glove compartment.

Were the pens diamond and gold plated? I'm not sure I would have gone for those with the car smoking.

 

[TomT]

He's a doctor. Many of them suffer from a God complex and refuse to seek help from anyone.
There is an old saying in general aviation: "The scariest thing in the air is a doctor in a Bonanza..."

Wouldn't most people, as a precaution, stop to check for damage drive after such an impact?

 

[TonyWilliams]

He's a doctor. Many of them suffer from a God complex and refuse to seek help from anyone.
There is an old saying in general aviation: "The scariest thing in the air is a doctor in a Bonanza..."

The doctors have moved on to the Cirrus, so all is well as long as the parachute is up there.