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Beth Stackpole
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No doubt, debate
Beth Stackpole   4/13/2012 7:34:07 AM
Chuck, I found myself debating myself just reading the article. I would fully expect, as the experts note, that there would be controlled explosions during the testing of experimental technology like EV batteries. You figure, in the lab, they would be contained, managed, not a biggie. But reading further into your article and hearing what the town Mayor is reporting is a totally different story. Injured people, blown-out doors--those don't sound like effects from a controlled experiment. That sounds like serious stuff that could make people leery about the batteries for a long time.

williamlweaver
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Platinum
Re: No doubt, debate
williamlweaver   4/13/2012 7:55:03 AM
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Beth I share your thoughts. I'm now wondering what Hollywood and the Media will do with this information. We have some nice examples: 1979 movie The China Syndrome had quite an effect on public perception of Nuclear Energy, the 2010 CSI Episode "Fracked" did quite a bit to fuel rumors about the ills of Fracking, the 1992 TV movie Dead Ahead: The Exxon Valdez Disaster dramatized the dangers of petroleum use, and there is a rumored movie in production based on a New York Times article from December 25, 2010 titled Deepwater Horizon's Final Hours. I'm all for disseminating factual information about the development of new technologies, but I'm curious how this event will shape public perception of battery research.

Alexander Wolfe
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Blogger
Re: No doubt, debate
Alexander Wolfe   4/13/2012 9:42:39 AM
Well, they were doing a test where they were trying to get the battery to fail. It just failed in a more "explosive" manner than they expected. I think (and forgive me for using this word) that this is being overblown a bit. If you left your Clorox bottle at home uncapped for a week, with all the windows and doors tightly sealed, you'd have some very sick occupants. That doesn't mean Clorox is something that shouldn't be used or sold.

Scott Orlosky
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Re: No doubt, debate
Scott Orlosky   4/14/2012 7:48:31 PM
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Unfortunately, people are notoriously bad at assessing risk, even when given accurate information.  Stoking fear by sensationalizing an event doesn't help the situation.  To be fair, driving a car is probably the single most dangerous part of anybody's day.  Yet, despite the 40,000 deaths a year from this activity (in the U.S.) you don't hear any public outcry.

sanfordsautomotive
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Iron
Re: No doubt, debate
sanfordsautomotive   4/13/2012 1:04:32 PM
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I glad I ran across this article, I am in the process of transplanting the "guts" of a wrecked 2006 Toyota Prius in to a 1992 Lexus es 300 Donner car (engine and drive train removed of course) I would like to add three more batteries in parallel to the existing battery to extend the mileage before the gas engine kicks in and starts the charging process, I can only imagine the damage it could do to my vehicle or a individual if there was an explosions or fire. 



Nancy Golden
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Re: No doubt, debate
Nancy Golden   4/13/2012 4:48:28 PM
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I am ambivalent regarding this as well. In other blogs I have brought up safety only to be told in so many words that I was being overcautious. Yet nobody brings hard data as to the safety standards that batteries are tested to in vehicle use when they do so, they just say that their EV works great. I still haven't had anyone tell me if the volatility increases with density...has anyone checked out the videos that are available online as to what happens when a lithium ion battery is thrown into a barbecue grill (analogous to an EV and an ICE collison where there is a fire). It's not very encouraging.

Stuart21
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Silver
Re: No doubt, debate
Stuart21   4/16/2012 11:09:49 AM
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& I want to know what happens when an EV car gets dunked - fresh water or salt water. No discussion of this AFAIK. There is potential (pun intended) for electrocution.

I have proposed a new Australian Design Rule that - any - new car (EV too) must survive a 24 hour dunking in fresh water without having to be written off. Sure change oils minor repairs but insurance companies should not be stuck with poor design choices of manufacturer.

GlennA
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Gold
Re: No doubt, debate
GlennA   4/16/2012 11:23:29 AM
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By what reasoning did you decide that a 24 hour submersion in fresh water is a vaild design constraint ?

Or was this tongue-in-cheek ?

Stuart21
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Silver
Re: No doubt, debate
Stuart21   4/16/2012 12:37:26 PM
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Not at all.

There are many variables such as Ph, temperature (I anticipate room temp), Salinity, turbidity (Clear) etc etc. So best to assume a fairly common standard - fresh water is most common. This could be changed to a certain salinity in 5 or 10 years or so - depending upon how the original design rule 'performs'.

The length of time would be sufficient to ensure manufacturers protected against electrolysis - i.e. not destroying computer and instruments. A short dunking would not test this. All materials should survive 24 hrs in fresh water, tho dissaembly, cleaning, drying etc, new oils, filters etc may be required.

With the extreme weather we have been having, insurance cos have been enjoying 'windfall losses' due to poor design & test procedure of manufacturers, and poor driving choices of drivers.

Yes, I have put quite a bit of thought into this proposal.

GlennA
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poor driving choices of drivers'
GlennA   4/16/2012 1:03:26 PM
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Then why stop at 24 hours immersion in fresh water ?

Why not include a parachute for drivers that might drive off of a cliff ?

Or super-energy-absorbing bumpers to resist a crash into a wall at 100 mph ?

Or require a car be able do roll 3 times, land on its tires, and drive away ?

Certain features, although nice, are not cost-effective.

Stuart21
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Silver
Re: poor driving choices of drivers'
Stuart21   4/16/2012 1:17:32 PM
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You can propose whatever design rules you like mate, I'll stick to mine.

That car computer that costs hundreds of dollars to replace when it doesn't work can be waterproofed for around a dollar. Cost effective. Etc etc etc.

I am an automotive engineer and industrial designer but am not associated with the auto industry at the current time.

I know what can be done.

Where are you coming from, Glenn?

GlennA
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Gold
Re: poor driving choices of drivers'
GlennA   4/16/2012 1:31:07 PM
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I have a bit of experience with the structural assembly of cars and trucks.

Waterproofing the computer is only the tip of the iceberg.  The electric window motors, the radio, the navigation system, the upholstery, the power seat motors, the heater / air conditioner fan and vacuum controls, the electric fan(s) for the radiator, the remote trunk open, the a/c compressor clutch, the power sunroof, the power door locks, the air bags and sensors.  The list could go on and on.

Do you propose to include all of these ?  Otherwise what you have is a car that has a computer that can be salvaged, while the rest is a loss.

Rob Spiegel
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Blogger
Re: poor driving choices of drivers'
Rob Spiegel   4/16/2012 4:30:14 PM
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Good point, Glenn. Yet my kids will probably see some of these wild ideas come true, such as cars that drive themselves and won't crash into each other. Those kinds of advances may be expensive, but in lives saved, it's the equivalent of ending a war.

MIROX
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Platinum
Re: No doubt, debate
MIROX   4/16/2012 5:55:53 PM
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2007 OKA NEV ZEV was in real life submerged in 3 feet of rainwater and while all other cars parked at that lot in Henderson NV during that flash flood rain storm were total losses (about 18 of them), the car could not only be driven off with still about 18 inches of water in it, it only needed to have the throttle sliding pot 5K resistor replaced as the "dirty water" that got in to it made it not operate "smoothly" there after when it dried out.

The car is 48V DC nominal with 4kW/h battery pack and 12 V DC aux battery for normal car equipment (Both sealed lead acid batteries)

So a well designed EV and actually operate as a submarine completely submerged under any water, the high voltage in other designs will NOT cause much other than some water being electrolized to H2 and O2 but that will just bubble off. 

But of course NOT SEALED ECU will most likely fail, the one in OKA is potted in RTV after initial test and "burn-in" and so far only 2 have failed since 2003, both due to customers shorting out the output (450 A fused) while experimenting to make the car go faster than the FMVSS mandated 25 MPH limit for LSV.

More than flood, water or anything else customers EXPERIMENTING with their vehicles are far more common causes of problems - they do it with hopping up Hp on diesels, and "tuning" normal cars to self destruction, yet that seldom makes much news - but lot of Internet noise when the OEM denies warranty repairs on "modified" vehicles.

www.okaauto.com

 

 

melllowfelllow
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Gold
Re: No doubt, debate
melllowfelllow   4/16/2012 5:57:20 PM
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@Stuart21 - Your proposal is exactly what is wrong with so much of the world today. I would think that a bit of common sense and root cause analysis would yield a better [for the consumer] solution. I'm not sure how often that Aussies dunk their vehicles, but I will not let that stop me from commenting.

Problem statement: Insurance companies payout too much money to repair water damage to dunked vehicles.

Comment: I hope that you do not have a technical background because the cost to protect the electronics [design, test, implement, increased servicability cost, and upgrade to components in many cases] is not insignificant.

Proposed solution: Pass on to every vehicle purchaser the cost for '24 hour dunk protection'.

Alternative solutions:

1. Make 'vehicle dunking insurance' an option available at extra cost or 'not covered'.

2. Increase the price of your insurance so that it is spread among each of your customers.

3. Sames as #2. Pretend that you are a real insurance company, assess the risk, compute the cost, and set the consumer price.

4. Terminate participation in the sale of automobile insurance.

6Lz

Stuart21
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Silver
Re: No doubt, debate
Stuart21   5/1/2012 5:09:08 AM
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"@Stuart21 - Your proposal is exactly what is wrong with so much of the world today."

Thanks, that is the nicest thing anybody has said to me all day.

Are you saying that this vehicle must be scrapped?

http://www.youtube.com/watch?v=uC6G-m6aAiw&list=UU1712XEXMIRQW1-spPVK0Ng&index=77&feature=plcp

It is absolutley ridiculous that a very expensive vehicle should be scrapped because of a few hundred dollars worth of electrical components - most of which can be waterproofed anyway. It is an SUV fergorsake - they are designed for the rough stuff. Or should be.

And those that merely 'appear to be' designed for rough stuff, it should be at manufaturers expense for repairs that would not be required with proper design.

 




melllowfelllow
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Gold
Re: No doubt, debate
melllowfelllow   5/1/2012 12:50:30 PM
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"@Stuart21 - Your proposal is exactly what is wrong with so much of the world today."

1. You do not make your case with relevant facts. Something like "27% of all cars on the road today will end up submerged" could be a good start if it were true. The actual number is likely so small that everyone would see its true relevance.

2. Just like a politician you bring up an issue in isolation with one or two specific examples. A true crusader would 'rack and stack' all of the fixable automotive issues and illustrate that you issue was at the top of the list.

3.One thing that I know after bringing products into the marketplace - When I am doing the work, it is very easy for me to underestimate the cost and effort - when someone else is doing the work outside of my workplace, it is almost guaranteed that I will miss any scope and cost estimates that I might make. This is especially true in the automotive industry where what would be a 1-2 week change at a computer company could be a 6 month or more effort at a automobile manufacturer. Afterall, you do want the manufacturers to thoroughly test for unintended consequences.


4. I thought that an insurance company's job was to assess risk and set a price to cover that risk.

RE:"Are you saying that this vehicle must be scrapped?"

Quite the dramatic statement. The vehicle is still worth several thousand $USD.The insurance company probably totaled it - assuming the owner had a valid claim and didn't just drive on thin ice.


Why was it parked at the bottom of a lake??

Was it your car??

Do you propose salt water and fresh water be covered??

Would there be a depth limit??


Oh, did I mention that your problem analysis is flawed?? It is true that the 'tall pole issues' are expensive electronics, but that is not the whole story. Having repaired a few vehicles that were only half submerged due to flooding, a few other issues that come to mind are: mold [a delayed effect], connector failure [often delayed] due to corrosion, failure of any light bulb socket [delayed] due to corrosion, gas gauge sensor failure due to corrosion, relay failure, CV or U joint failure [delayed] due to water trapped inside, failure of any swiches due to water trapped inside, catalytic converter[s] failure, radio speakers failure, CD-ROM failure, radio failure, possible leather upholstery failure, failure of some of the 1-2 dozen motors and solenoids, extensive labor to remove water from places that it should not be [motor, transmission, differential, dash instruments, doors, various inaccessable interior nooks and crannies, etc.] - Oh, I forgot, we will also waterproof these areas. It might be easier to adapt wheels to a submarine and only sell 'dunk insurance' to folks that purchase such a vehicle.

6Lz


tekochip
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Platinum
Spontaneous Energetic Disassembly
tekochip   4/13/2012 9:55:06 AM
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Beth, it does seem like they are trying gloss over a serious failure. Certainly, gasoline is not exactly a stable compound, and we drive around every day with tens of gallons of the stuff being pumped at high pressure just inches away from us, so I'm not really worried about an increased risk. Just the same, the quotes read like the Three Mile Island report and I half expect that they will soon be saying they experienced "rapid oxidation" rather than a fire.


naperlou
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Blogger
Re: Spontaneous Energetic Disassembly
naperlou   4/13/2012 10:51:47 AM
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tekochip, I like your terminology.  Were you in the aerospace business, or the military? 

tekochip
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Platinum
Re: Spontaneous Energetic Disassembly
tekochip   4/13/2012 11:40:22 AM
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Thanks, no, reading the article just reminded me of the descriptive phrases used in the Three Mile Island accident report.

warren@fourward.com
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More dangers
warren@fourward.com   4/14/2012 3:33:59 PM
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I am not as worried about the exploding battery issue as I am with the dangers involved to the poor mechanic who has to work on these things.  The high voltage can kill!  Plus, the computer goes through a systems check periodically and activates, amongst many other things, the brakes.  If you are working on the brakes at the time, you might just lose a finger!  Mechanic friends of mine are scared of the electric cars.  You can't always get a factory tech, so the small-town mechanic might be the highest risk group of all- not Alaskan crab fisherman dangerous- but significant nonetheless.
 


Jack Rupert, PE
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Platinum
Re: More dangers
Jack Rupert, PE   4/15/2012 3:04:04 PM
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I agree Warren.  This incident happenened during a factory test.  I'm sure there could be other "extreme" tests done on gasoline powered cars that would make them go boom as well (Ford Pinto anyone?).  As you mentioned, voltage is a much bigger issue.  I used to work in an industry that due to it's nature needed to be extremely safety aware and pretty much everyone was well trained in their jobs.  No back-yard mechanics there.  You needed to be an card-carrying electrician to work on anything over 24VDC.  I worry about somebody who knows just enough to be dangerous trying to fix one of these in his driveway.

DanielJoseph
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Gold
Re: More dangers
DanielJoseph   4/16/2012 11:07:12 AM
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I am having a tough time with the sensationalism going on here by engineers and others.  The battery is experimental - they were trying to get it to fail - it failed which was the whole point of the test.  The test would have been a failure if they did not discover the failure point.  Was there some other issue with the test chamber that caused an unexpected buildup of gases - can't say, but that is what the story should be about - and of course those affected by the aftermath.  Also, worrying about mechanic working on an electrified car is almost as mis-informed.  Cars have been electrified with enough power to kill someone for quite a while.  My point is mechanics are trained for these things.  The new mechanics will be trained with the same training that electricians receive who work on high voltage systems.  Just to be clear, every Volt runs on the same inverter technology that has existed in factories for years.  I am not being trite here, it is simply something to be learned not to be feared.  So please, stop with the worry wart stuff! 

kenish
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Platinum
Re: More dangers
kenish   4/16/2012 4:25:49 PM
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@Daniel- Agree.  Recently a Rolls Royce facility was pretty much demolished when a "blade off" test of a jet engine didn't go as expected.  It was a test, and I'm sure the results will contribute to a safer design more than if the test had the expected result. 

Tim
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Platinum
Re: More dangers
Tim   4/15/2012 6:00:08 PM
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Glad to hear that my battery will not explode, but I agree on the voltage danger.  First responders had significant concern with the latent voltage of the lithium ion battery stack on EV's when they were introduced.  It would be a terrible thing if they needed to use the jaws of life to peel the car away from you after an accident only to be hit with high voltage from the car during the rescue. 

gearhyde
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Iron
Re: More dangers
gearhyde   4/16/2012 10:55:41 AM
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Personally, I think the EV battery dangers are being way overblown.  That's one of the problems with today's social media.  Have you ever heard of the dangers of the common 12 Vdc or 24 Vdc battery exploding or causing fires?  I doubt it and yet it has happened. 
Back when I was still an automotive mechanic, I was checking over the electrical/charging system of a vehicle that was brought with a hard-to-start problem.  The charging and starting systems all checked out which left the battery.  When I did a load test on it, the top of the battery blew off.  I was fortunate that I was wearing glasses, otherwise I would have had acid in my eyes.  As it was, I had to have stitches where the battery top struck my face. 
My point is this: Everyday we all are in close proximity of items that can hurt us.  Our laptops and electronic devices all have lithium ion batteries.  They can can explode as well.  As one poster pointed out, our cars all have tens of gallons of gas and yet we don't rail about the dangers of that. 

ChasChas
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Platinum
never say never
ChasChas   4/16/2012 11:00:28 AM
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I personally experienced a golf cart battery explosion - said to be in good working order - lead acid of course.

We do the best we can, but "never say never."

 

ervin0072002
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Gold
Uneducated Media
ervin0072002   4/16/2012 12:50:34 PM
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Yep got to love the Hype.... The problem as many of you mentioned is our media. Back in the day it was all about the truth and having the story correct... Now it's all about the best story (regardless of the facts behind it, if it sounds good put it on the front line). Now To be honest it is sort of hilarious. I'm a test engineer and I do sit down and asses the risk that each test has. Overheating a battery in a closed unvented room might have raised a few flags on my review... Just Saying..

 

 

William K.
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Platinum
Explosions, betteries, and other concerns.
William K.   4/16/2012 5:49:10 PM
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For starters, whatever it was at GM that went boom was probably not a battery explosion. To get technical about it, in an explosion the propogation is by shock waves, which travel at the speed of sound in whatever media is exploding. And sound travels quite rapidly in a solid. An example of explosions is detonation, known as spark knock, in a gas engine. Normal running is just rapid burning. The blowup could have been caused by hydrogen gas liberated by charging some kind of battery, and being ignited by some accident, such as a small spark. The quite rapid combustion brings about a corresponding increase in temperature and, therfore, pressure, which can do a great deal of damage. Some dynamometer cells are built with "blow-out" doors, so that the rapid combustion resulting from a spray of gasoline igniting will not cause a lot of damage.

The chance of a true explosion in a production type battery is nonexistant because it has been designed out. Things can still burn and get messy, but by the time a product gets near to the prototypem stage the pressure relief system has already been put in place, even if the need for it is only theoretical. 

MY bet is that whatever battery caused the incident, it was much earlier in 6the stage, closer to the time when they check to see how many charge-discharge cycles some new battery technology can live through before it loses capacity. And the failure was most likely in the venting system that handles the gasses produced in the charge discharge cycle.

But you would not tell the media that because they would distort it so much that it would lead to a general panic, which, after all, is what the news people love to do.

Charles Murray
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Blogger
Re: Explosions, betteries, and other concerns.
Charles Murray   4/16/2012 6:00:49 PM
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Good points, William K. Based on my discussion with experts, I think there's a possibility that the blast doors did exactly what they should have -- open automatically in the presence of a gas release. I'm waiting for additional information...

William K.
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Platinum
explosions, batteries, and other concerns.
William K.   4/16/2012 6:18:04 PM
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How did part of this discussion wander off into how vehicles survived submersion? Most auto companies don't intend for their products to be used under water. Although the old JEEP could be run under water if that option was installed. At least that is what I read. Immersion of any vehicle not intended fr immersion would call for getting water out of a whole lot of places that it was never intended to have water in. But that is a whole different thing. 

melllowfelllow
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Gold
The Sky is Falling
melllowfelllow   4/16/2012 6:21:41 PM
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One three letter word jumped out at me - LAB. IMO, anything that happens in a lab - good or bad - potentially has no relation to 'real life'.

I am tired of media sensationalism. If there is a bit of a storm somewhere, the 'news' becomes consumed by the 'news about weather'. The formula seems to be that if the subject has FUD [Fear, Uncertainty, and Doubt] potential, take it to the extreme. Boring subjects, like a fabric fire in a clothing plant, do not include the FUD factor so we do not get stories about the dangers of wearing clothing.

Every lab 'incident' that I can recall with my questionable memory has had it root cause traced to human error [and then sometimes covered up by some 'mumbo jumbo' to confuse management].

6Lz

bobjengr
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Platinum
EV BATTERY
bobjengr   4/16/2012 8:01:40 PM
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Quite frankly, I applaud the efforts of General Motors for making an effort to know more about their product than anyone else—in this case the EV battery.  I retired from General Electric Appliances and we always applied ETPs (Engineering Test Procedures) to products just to see what would happen if and when they were misused.    These ETPs were "over and above" all third party standards existing to qualify an assembly and deem that assembly safe and functional.   I am sure GM has laboratory test procedures governing the test itself and defining pass / fail criteria.  I definitely agree with "mellowfellow" in that hyperventilation rules the day and certainly the media relative to technical issues.  Mark Twain was correct when he stated: "It ain't what we don't know that hurts us; it's what we know that ain't so".  Let's let GM do their thing!

RMarksEV
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Iron
Re: EV BATTERY
RMarksEV   4/19/2012 7:14:09 PM
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There may be more to the story that I can share. I am in Detroit and I did work for GM for 25 years including 5 years on EV1, almost 20 years ago. I quit over lack of intelligence in management.

SAE has some very destructive standard battery tests and this was probably a test to heat the batteries to 200 degrees C above ambient (about 375F).  Very severe but necessary test to see what happens and what gases are released.

It was mentioned in Detroit that Hydrogen Sulfide was present (commonly known as sewer gas) which will explode.  (in auto industry we refer to this as a thermal incident).  I do not know what created the H2SO4.

My belief is that when GM retired out all of their old dogs and then hired a bunch of new college kids, they loss an incredible amount of knowledge, skills and experience.  I truly believe, the test people were playing video games and then a bell rang and they said OMG! and then the thermal incident happend.

I think it is fortunate that only one person was hurt, but it does say something about keeping your old dogs around.  Experience tells you why it is important to follow test protocols and procedures very carefully.  They probably didn't. No excuse for this.

I think the same issue occurred in the design of the Volt battery pack.  I'm an old dog and one look at the pack, I knew they were not going to be able to retain the cooling fluid consistantly in production, let alone in a crash shake-up. When 50% ethylen glycol is allowed to evaporate, pure ethylene glycol does burn.  Thus the several months between crash and thermal incident.

Did GM learn anything from this? Doubt it.

bobjengr
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Platinum
Re: EV BATTERY
bobjengr   4/19/2012 8:32:33 PM
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I agree completely.  I retired from Roper (GE owned company) and it seemed as though we had to keep learning the same lessons over and over again.  Each year, GE demanded a 10% headcount reduction and that included people from the engineering staff.   With retirements and reductions, we ended up with a fairly young staff.  We lost the history and experience that, in my opinion, makes a company viable and provides transparency between the "generations".   I think this is an ongoing problem with manufacturing and when you add movement of companies to off-shore locations you lose entire generations.     For some industries, we are becoming a nation that doesn't really know how to design or produce.  Please note, this is my opinion and I certainly welcome rebuttal.

GlennA
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Gold
Re: Old dogs ?
GlennA   4/23/2012 9:30:26 AM
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While I worked for Panasonic Factory Automation, I spent a lot of time at Celestica, then a subsidiary of IBM.  To reduce pension obligations, most employees were employed for 12 months, with a possible 3 months extension.  Some of the Celestica employees thought that I was also a Celestica employee.  I was often called to look at a machine problem.  Several times it was a problem that I had seen before and I knew what adjustment was needed.  The frequent rotation of Celestica employees meant that they did not have that continuity of experience.  Their plan was to replace experienced employees regularly, an intentional brain drain.

lewisglarsen
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Iron
Explanations for GM's explosion implausible, so far
lewisglarsen   4/22/2012 2:58:01 PM
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Something doesn't quite add-up with GM's claimed theory cum 'explanation' that an accumulation of hydrogen sulfide gas (H2S) vented from deliberately overcharged prototype (presumably Lithium-Sulfur chemistry) A123 batteries caused the large explosion that damaged their battery R&D facility. This purported explanation for the recent blast seems implausible because venting of flammable gases from failing, overheating batteries is a long-well-known phenomenon. That being the case, the new purpose-built lab (built in 2009) would have been deliberately designed with best practices air-handling/ventilation systems that can rapidly turn-over and exhaust air from test areas in the facility to prevent just such a build-up of flammable vapors from ever accumulating to the point where large explosion could potentially occur. Why would that important, built-in safety support system have magically failed during this particular incident? It doesn't make sense. Second, GM publicly claims that the catastrophically failing battery pack was supposedly fully intact after the explosion --- frankly, I don't believe that 'fact' either.

 

Readers may be interested to know about the existence of another little-known type of Lithium battery failure mode that albeit rarer, may even be more serious than 'simple' overheating. According to a Japanese Li-ion battery manufacturer, it happens randomly in roughly 1 out of every 4 to 5 million battery cells, regardless of their chemistry.

 

This somewhat obscure type of failure mode is cryptically called a "field failure" by some battery manufacturers and involves catastrophic thermal failure of a single cell. While it is often thought to be associated with internal shorts and electrical arcing within a somehow defective cell, battery manufacturers admit privately that this peculiar failure mode is not well-characterized and very poorly understood --- they are presently at a loss for ideas about exactly how to mitigate such a problem. Scarily, they are well-aware that if just a single cell in a large, multi-cell EV battery pack fails in this particular manner, it can potentially trigger an even more catastrophic large-scale thermal runaway event that rapidly propagates through an entire battery pack, destroying adjacent cells via thermal fratricide as well as possibly the interior of an EV.

 

In May 2010, academic researchers at Oxford University published a new and perhaps important paper that many believe implicates the involvement of Lithium metal dendrites in a significant number of Li-ion battery failures (please see R. Bhattacharyya et al., "In situ NMR observation of the formation of metallic Lithium microstructures in Lithium batteries," Nature Materials 9 pp. 504 - 510). What is of great concern from a safety standpoint is that nanoscale internal metal dendrites that are prone to shorting-out grow spontaneously over time as a battery ages and goes through many charge-discharge cycles.  A battery pack may be perfectly safe during the first months of ordinary use; however, dendrites grow inside over time, increasing the probability of dangerous internal electrical shorts as time goes on. The problem is that nobody in the world has any working experience with extremely large multi-cell Lithium-chemsitry battery backs used for periods of many years. Lastly, nanoscale internal metallic dendrites can potentially form and grow in almost any type of Lithium battery chemistry.



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Texas Instruments is rolling out a new microcontroller that could make the design of sensor networks and data logging systems simpler and less costly.
Made By Monkeys highlights products that somehow slipped by the QC cops.
From pitchers and forwards to quarterbacks and defensemen, we offer a peek at some of the more memorable engineers in sports history.
IBM announced it is dedicating $3 billion of funding over the next five years to research and development of new processor technologies.
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