HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
REGISTER   |   LOGIN   |   HELP
Blogs
Electronic News & Comment
Video: Impact Caused Tesla Battery Fire
10/4/2013

A CT scan image of a battery cell shows breakdown of layers directly below an indentation. A recent report from Underwriters' Laboratories Inc. suggests that such dents in the casing are a possible failure mechanism for lithium-ion batteries. 'The resulting high stress/strain will lead to a mechanical failure of the separator (with failure of the casing), allowing for direct contact between electrodes at a distance only a few layers below the casing surface,' the report says.   (Source: Underwriters Laboratories Inc.)
A CT scan image of a battery cell shows breakdown of layers directly below an indentation. A recent report from Underwriters’ Laboratories Inc. suggests that such dents in the casing are a possible failure mechanism for lithium-ion batteries. “The resulting high stress/strain will lead to a mechanical failure of the separator (with failure of the casing), allowing for direct contact between electrodes at a distance only a few layers below the casing surface,” the report says.
(Source: Underwriters Laboratories Inc.)

Return to Article

View Comments: Oldest First|Newest First|Threaded View
Page 1/5  >  >>
naperlou
User Rank
Blogger
Safety rating
naperlou   10/4/2013 9:29:03 AM
Chuck, Didn't Tesla get a top safety rating just recently for the S?  This is a problem with EVs (and hybrids) that use Lithium Ion batteries.  I am not sure that the testing agancies really know how to characterize the failure modes of these batteries.  As I have mentioned before, there was an incident in China where an all electric cab of local manufacture caught fire and burned up the driver and passengers completely after a collision with a car that drove away.  This is very worrisome.

Ken Sides
User Rank
Iron
Battery quick-release drop in case of fire emergency
Ken Sides   10/4/2013 12:31:10 PM
NO RATINGS
Since the Tesla Model S batteries can be swapped out in a few seconds at their roadside stations, there must be some sort of quick release that would make it possible in an emergency to drop the battery pack and roll the car away from it, thereby saving the vehicle in case of battery fire. 

Perhaps there should be a small, separate battery just for the purpose of driving the vehicle a few feet to get off of and away from the dropped main battery.

Charles Murray
User Rank
Blogger
Re: Battery quick-release drop in case of fire emergency
Charles Murray   10/4/2013 6:37:52 PM
NO RATINGS
That's an interesting idea, Ken, especially in light of the fact that firefighters had so much trouble extinguishing the battery fire.

Charles Murray
User Rank
Blogger
Re: Safety rating
Charles Murray   10/4/2013 6:41:47 PM
NO RATINGS
You're right on the money, naperlou. Yes, Tesla has "fives" (best rating) across the board in NHTSA's safety ratings. And, yes, the methodology for the ratings is well established. I agree that the ratings agencies don't yet have a handle on how to characterize the relatively new phenomenon of lithium-ion failures.

naperlou
User Rank
Blogger
Re: Battery quick-release drop in case of fire emergency
naperlou   10/5/2013 12:13:12 AM
NO RATINGS
Ken, my understanding of the battery swap out machine is that it simultaneously unscrews a large number of bolts, drops the battery down, then raises another battery up into place.  Reportedly, it is the same piece of equipment they use in the factory.  It is not a mobile piece of equipment.  In videos of it working, the car is driven up over the device.  This is not a quick relesae mechanism.  The device reportedly will cost Tesla $500K to intsall. 

If the battery is susceptible to being breached the way this one was, any auxiliary battery would be susceptible as well.  If it was anywhere near the part tha caught fire, it would also catch fire.  Also, the battery weighs over 900 lbs., so I am not sure your idea would work. 

I think the idea of having the battery basically cover the bottom of the car is a very bad one.  This could prove their undoing.  Now they will probably have to put some sort of shielding there.  That will increase the weight even more.

Nancy Golden
User Rank
Platinum
Poor Defense
Nancy Golden   10/6/2013 4:51:48 PM
NO RATINGS
"Such occurrences are rare, however. A Tesla spokeswoman told Design News that the Model S has collectively been driven 83 million miles at this point, with dozens of known accidents, and no such battery problems, until now."

Seems to me that this is a misleading statement and is a poor defense for Tesla battery safety. 83 million miles refers to driving distance but does not take into account an impact with an object - and "dozens of known accidents" does not give any quantifiable data regarding this specific issue. 

richnass
User Rank
Blogger
Re: Poor Defense
richnass   10/6/2013 9:20:29 PM
NO RATINGS
A small fire? Did they see the video?

patb2009
User Rank
Gold
Re: Battery quick-release drop in case of fire emergency
patb2009   10/6/2013 11:33:51 PM
NO RATINGS
apparently the battery has an armor plate beneath it, 1/4" thick. However, 

hit something hard enough, fast enough and it will rip through almost anything.

Lets not forget some minor ice sank the Titanic. 

 

Now that said, Lou's idea of dropping the battery pack isn't neccessarily a bad idea.

if you have a fire, it would seem easiest to have some explosive bolts on the body side, that would cut the structural attachments and let the battery drop off.  You would need a small internal battery to drive away,  but, it could be done as a future upgrade.

 

 

Elizabeth M
User Rank
Blogger
Re: Safety rating
Elizabeth M   10/7/2013 4:02:22 AM
NO RATINGS
Wow that is scary stuff! It's unfortunate this keeps happening, because it certainly isn't going to do anything to promote the use of hybrid vehicles and EVs. It's especially troubling because of Tesla's high rating, as Lou points out.

GTOlover
User Rank
Platinum
Re: Safety rating
GTOlover   10/7/2013 8:54:49 AM
NO RATINGS
So the Pinto, Chevy saddle tanks, and the recent Jeep recalls should all be put aside if we let the Tesla get a pass? 

On the otherhand, debris is a part of the road. If consumers expect the cars to be 100% safe, then the only solution is to get rid of the car. At least in this instance, the driver was able to pull over and get out. In fact, I think this was explicitily discussed when many here at DN were critical of the Boeing batteries. Lithium ion chemistry in an airplane, not so good as the option is a plane crash (or crash landing). But in an automobile one could pull over and get out of the car.

Page 1/5  >  >>
Partner Zone
More Blogs from Electronic News & Comment
There's good news and bad news regarding the sub-systems of today's late-model vehicles. The good news is that new engines and transmissions are more trouble-free than in the past. The bad news is that the infotainment and DVD players are still prone to be "buggy."
Government fines and recalls are heightening the need for automakers to adopt more safety standards and software verification techniques, experts at EE Live said this week.
The coming era of self-driving cars will call for a major change in engineering culture, an embedded design expert said this week.
For decades, the corporate path to the chief executive's office has often passed through engineering. Automotive, computer, electronics, and oil companies have frequently drawn their leaders from the engineering ranks.
The Texas Motor Speedway has flipped the switch on a high-definition video board that uses 14 million LEDs, weighs more than 200,000 pounds, and is 80% larger than the Dallas Cowboys' world-renowned scoreboard.
Design News Webinar Series
3/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
2/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
12/18/2013 Available On Demand
11/20/2013 Available On Demand
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Apr 21 - 25, Creating & Testing Your First RTOS Application Using MQX
SEMESTERS: 1  |  2  |  3  |  4  |  5


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: April 29 - Day 1
Sponsored by maxon precision motors
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service