I'm curious about the stats on the problem/non-problem. Is this a rare occurrence or is it statistically significant -- as the Ford Pinto was? Also, are there certain circumstances in which a fire occurs? The story shows an impact test. Is this how the fires get started?
The comparison with a gas engine points out the inherent problems with lithium, not similarities. If there is an accident, the first thing that happens in a gas powered car is the fuel pump shuts off, denying the accident scene fuel. Where gasoline is burned we are protected by cooling systems, lots of metal, and a firewall. Nothing like that can be done for a lithium battery: in an accident not only do you get the mechanical conditions for a short and subsequent overheating INSIDE the fuel supply, but loss of cooling is also probable. Do you get an explosion proof firewall with lithium? doubtful.
A better comparison would be with a nuclear power plant. If a plant shuts down (for any reason), backup power is required to keep the core cool, or you get what happened in Japan. If the cooling system (or what powers it) is compromised you get a chain reaction (just like with lithium).
Nothing is risk free (gasoline powered cars certainly are not), but be careful not to unrealistically minimize the risks for the greater cause of "greenliness" or technology for technology's sake.
I don't totally disagree, but I niether completely agree with your rationality. I mean, true, no tech will ever be perfect, safety is never perfect. That's why they attack the safety of these products, because it is never perfect and uneducated/uninformed people like to use the absense of perfection or the asbsense of 100% certainty as a means of escape. They did the same with the EV-1, now they intend to do the same with the Volt. My intent wasn't to downplay safety concerns with electrics, my intent was to expose the over exageration of these concerns. 3 fires, 2 had nothing to do with the car and the third was in a collision so bad that any insurer would have clasified it as totalled. Now compare that to the gasoline powered car stats stated above and tell me you are honestly concerned about the fire safety of electrics... do you really feel its appropriate to offer a buy back for the Volt over these 3 false fire examples, while not offering the buy back on the gasoline cars which are catching fire consistently every minute and a half across the US?
Look, I'm not trying to downplay safety concerns with eletrics, neither am I trying to hype the safety concerns of gasoline; I feel gas is as safe as it can be, they've done a good job, but it isn't perfect and THOUSANDS stilll die every year in car fires and explosions. When you do an honest comparison, electric is safer hands down. Yes, you have a blast wall for protection in gas cars, but that only is intended to protect from explosion and not fire... electrics cannot explode, but they can catch fire, so there is no need for a blast wall.
It is an unreasonable stretch of sincerity, to be concerned about a battery explosion when you have so much gas out there. I mean really, say I was holding a can of gasoline in one hand and say 100 D size litherium batteries in the other... which would you be more concerned about? I can tell you with 100% certainty that OSHA would be far more concerned about the gasoline, as would I.
I agree that gasoline powered cars are not safe. But your statistics are not relevent. The Volt hasn't been out a full production year, and there are only 0.006 *10^6 of them on the road. This is compared with 255 * 10^6 gasoline powered passenger vehicles. The real statistical comparison is by miles traveled (especially since the Volt has a much smaller range than gas powered vehicles). We don't have the numbers yet to really know.
What we do know is that lithium is inherently dangerous. Not because you can have batteries that short out, but because when they do it's catastrophic (a reaction that feeds on itself). This being an Engineering blog, the conversation should be about what is being done to APPLY the technology safely. If done right, it could be much safer than gas. If done "normally" (read with management involvement, ROI, profit margin, etc.) then I wouldn't let my family near one.
If you want safe and high efficiency, get a diesel. Personally, I have a gas-electric hybrid with NiMH (probably has it's own defects).
I don't disagree with all you state, I agree that if done appropriately, electrics will always be safer than a compairable gasoline car. Ultimately, any basic safety analysis would start with a comparison of energy density and volitility, both of which are higher with gasoline right now and probably will continue to be for the next 10 years... though batteries are improving.
Yes, my states aren't 100% comparable, you'd have to reduce everything and make it a per capita comparison. But still, one can look at this data and make a general order of magnitude comparison to draw the conclusions I did. If you disagree with the conclusions, then do the hard math and challenge them.... but I suspect your just challenging my methods and not my conclusions in which case I agree and attribute the problem to laziness.
I do disagree with the claim of "catostrophic failure" of lithum batteries when they fail. Again, an honest attempt at quick comparison, worst case senarios only: When a lithum battery falses, we end up with a short which could catch fire assuming the cooling system fails. When a gasoline tank fails, say in the case of the pino, gas leaks onto a hot surface, igntites, and could potentially ignitude the gas tank (it does happen though rarely) and you get an explosion. An explosion is obviously more dangerous than a fire in most circumstances. I could honestly say that a gasoline powered car could, theoreticaly, be more safer than an electric, but it would require greater isolation than their lithium battery counterparts due to energy density. They could cordin off the gas tank into isolated sections, but to pass the safety rating of electrics, it would have to contain more isolation. Generally, lithum batterys do not fail "catastrophically"... I mean, can you name one catastrophy that has resulted from a lithum battery failure? It all goes back to energy density.
Rob: Various news reports have mentioned the Volt in conjunction with three fires (see Brian Fuller's story at http://www.designnews.com/author.asp?section_id=1386&doc_id=236254), but two appear to have been unrelated to the Volt. So at this point, it's fair to say there's definitely no statistical significance. As for how the fires get started: Yes, impact can potentially play a role if the casing around the cells is dented, but we don't know if it played a role in this case.
Thanks for the additional information on the active cooling systems used for Li-Ion batteries. I agree with your assessment that engineering cost is a primary negative factor when considering the system-wide distribution and utilization of EVs based on this technology.
I don't do this casually, but there is a direct correlation between these Li-ion battery systems and Fission reactors: both require ACTIVE cooling. However, in the case of Fission reactors, destruction of the active cooling system is very rare and only occurs after secondary and tertiary redundant fail-safe systems have been compromised or damaged (as in the cases of TMI, Chernobyl, and Fukushima). Without data mining into the type of accident, a search estimates around 6 million vehicle collisions per year in the US -- each an event in which the active cooling system of an EV could be damaged or compromised.
The NHTSA has released a statement dated Nov 25, 2011 (http://goo.gl/Aww3m) describing the original fire that resulted more than three (3) weeks after a test crash in May 2011 and two (2) additional fires from tests recently performed on November 17 and 18, 2011. These recent tests employed protocols to specifically damage the battery cooling system. No roadway fires have been reported from the 6,000 Volts currently in use by customers. Multiply the number of sold Volts by 1000 and crash each one of them every year and it is not difficult for the risk analysis folks to set off some read flags.
My first vehicle at 16 was my family's 1971 Ford Pinto. My wife was involved in a near-fatal accident as a college student while riding in a Ford Pinto and investigators said she could thank the same torrential rain storm that caused the accident for preventing the ignition of the fuel that covered her and the car. We must continue to demand that accurate science and sound engineering practices win out over political and branding pressures in the development of Li-Ion EV technology.
Thanks, Bill for your comment. It sees like with the Volt fires, as with the Toyota unintended acceleration of a few years ago, there's no attempt to place the problem reports in context. First off, anecdotal reports, real or not, take on a life of their own and are reported and rereported until it makes it seem like there's a groundswell. Not that these initial three fires didn't take place. What I'm saying is, the results of the investigations never get passed around as a follow up. It was the same thing w the Toyota, which in retrospect involved many cases of driver error. As for the GM buyback offer, that's simply good crisis PR management.
I think the fire possibility isn't really anything to worry about. I think it may have the fear of electricity stigmatism more than anything. Kind of like the fact that the gas tank was located in the bottom of pintos scare. The pinto was well before my time and I really don't understand what the scare was with pintos was. I have one and have worked on just about all the classic mustangs and they all have the top of the gas tank as the trunk floor and you can see the back of the rear seat in the trunk. 500,000 mustangs sold and seems most everyone enjoyed owning the car. Lots of cars other than the pinto where built this way. I hope the volt falls into the mustang category and not the pinto.
Rod, according to Hollywood, your Pinto experience is not typical. If you do a survey of all car crashes in films or on TV, all car crashes result in fire & an explosion. This is specially true if you are a bad guy.
I understand your question. Is there a significant risk to the consumer, like there was with the Pinto? Others appear to have missed the point. It is interesting that there have already been 3 fires, with so few sold. However, the question should not be asked if there is an issue with the Chevy Volt Lithium-Ion batteries but if there is an issue with all electric/hybrid cars with large battery systems. Lithium-ion batteries were not stable enough to be used in consumer products until very recently. Before this, they we would explode above 70 degrees F. Consumers tend to think batteries are benign things - safe. They are energy storage devices and if mistreated can hurt people. They do catch fire and when they do, they burn hot. They also explode and they tend to explode in a cascading fashion.
To me for Chevy to be willing to buy back the vehicles from worried purchasers means that GM is starting to pay attention to customer reaction; after all GM has a reputation of putting vehicles on the road and letting the customer find the bugs for them.
It is very surprising to me (and unprecedented) that GM has extended the offer to buy back the car from worried owners. I would think that if you were going to buy a Volt, you would have done extensive research before handing over the money and driving off the lot. It seems any question of the car's potential safety issues should have surfaced long ago.
I don't think these issues are widespread and from what I've read, there were extenuating circumstances with a least a couple of the fires that might lead you to believe there was another cause--not the lithium ion battery. I think Chevy is offering the buy-back program to uphold their brand image and their commitment to the Volt and be seen as proactive, rather than reactive. The number of vehicles they're likely to buy back will pale in comparison to the upside of making consumers comfortable with their choice.
This is getting more and more blatant, they are trying everything in there power to kill any technology that can compete with fossil fuels; why not, they've been doing it for 50 years. I mean, please, if your concerned about car fires, you shouldn't be driving a on top of a 14 gallon can of gasoline. To bring to light the manipulation of the arguement, as stated in previous articles there have been 3 Volt fires reported, EVER! 2 of them did not originate from the Volt, as proven by firemen, and the 3rd was a car that was previously involved in a head on collision and was driven without inspection or service. In contrast, Here are some statistics:
Also according to the NFPA, 33 car fires are reported every hour across the country, with one person per day dying in a car fire accident in the years between 2002 and 2005.
· According to the National Fire Protection Association, there were 258,000 vehicle fires in 2007 and 385 deaths. There were 1,675 injuries.
· There is a vehicle fire every 96 seconds in the United States.
So, if your a person who is overly concerned about car fires, which is more of a concern, a gasoline car or an electric car?
If your Chevy, which should you be more concerned about, the Volt or every other gas car they produce? I mean some on, Chevy gasoline car fires are responsible for hundreds of deaths per year, yet I don't see them offering to take those back at no cost to the owner...hence the manipulation. Chevy is corrupted by big oil and they will do anything, even if it defies logic and common sense, to maintain that relationship with big oil.
Yes, there will be Volt mishaps. It is being sold to the general public. From previous posts I get it that 3 fires occured, two from non-battery events, and one blatant operator error in providing maintenance/repair after a collision. The Ford Pinto/Mercury Molotov was blessed by management to make do without a simple splash shield to keep gas from hitting the hot muffler in a rear-impact collision. A high revving engine, short wheelbase, short overall length equals very hot exhaust pieces. Management ran the numbers and decided that cost of a splash shield was a higher end cost of product than projected liability. Not to be outdone, Chevy had such poor quality control that when Cosworth wanted to hot rod the 1975 Vega, they spent months cherry picking the engine production line to find 2,000 suitable engines to receive the Cosworth hi-po hardware. The Vega engine had the same metalurgy as the Porsches of the day, and a radiator of unsuitable cooling capacity.
I'd also like to add that many automotive fires have been caused by far lower energy density storage devices, namely the lead acid battery! While the battery itself may have had few ignition issues the vehicle wiring has had plenty. A short in a starter motor solenoid can result in an overheating starter motor and/or its power cable. Fusable links in many instances have not opened on time. With the trend to thinner and thinner wiring to reduce vehicle weight and the talk about raising the bus voltage to 24 or 48 volts to further reduce losses, the peak fault currents will rise even for non electric drive vehicles.
Regardless of the energy source, the density and amount of "fuel" required to power a practical vehicle will always be dangerous. However, it is kinetic energy that poses the biggest threat to a vehicle's inhabitants.
bdcst Yes agreed, and others fires can be much worse and more spectaluar. Check out windmill fires for instance. But, let me get to the real problem is SAFE ENERGY. Not the battery or buss voltage. How do we get Safe Energy?
The question begs other Qs like what type, where from, at what cost, and the list goes on. Where from, has to be at the top if we want to move on so here is a partial answer that I hope all you young engineers pay attention to thoes flakey old reclusive types and ask the rigut questions. If you do this it WILL lead you to a valley of knowledge that engineering schools don't teach.
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anytime you sit in a vehicle that has enough stored enegery to propel a 4000+ pound object some 300 miles you are taking a risk.
Fortunately gasoline is a fairly safe fuel - its hard to ignite in bulk liquid form, msotly the vapors are extremely volatile.
The lithium is also hazardous, shorts created by physical shocks in abnormal conditions like collisions risk igniting the batteries. Apparently damage to the cooling system can also cause delayed fires - this is particularly worrisome because circulation cooling systems are active whereas all the gas tank protection is primarily passive in nature.
I guess we'll know a little farther down the road.
Manwhile, is it true that GM has only sold 6-10,000 of the very hyped Volts? Are they on track saleswise?
I heard that of 4 Chevrolet Volts involved in crash testing, 3 ended up burning down. 75% suffered total destruction. Of course I'm not sure I believe that, if Chevrolet conducted the crash tests and got those kinds of results then I'm sure they wouldn't have released the car for production.
Remember, when GM first tested airbags, the prototypes kept decapitating the dummies.
The danger of any exotic chemical batteries and energy cells is well known. The Bolder TMF cell can do a similar job powering hybrids...Remember the Chrysler EXS created some time ago? Bolder uses a LEAD ACID combination with plastic shielding isolating EVERY CELL in the pack. That cell system was used in the ESX. No fires, no leakage except from the damaged cells in a collision...The amount of standard car battery electrolyte is contained in the matrix. No more than a few drops per cel actually leaks out.
Contrast that to the problems the ( re) VOLT (ing) has.
Used regular materials in power pack construction and the problem goes away.
Too bad the company got outsourced to the pacific rim....
I think at this point we clearly don't know the complete range of risks in the Volt. Nor, re the earlier comment, do we know exactly how many Volts have been sold. We'll be keeping up with both issues in our continuing coverage on Design News; thanks for the comments and for bringing these issues to the fore.
Alongside gasoline-fueled fires, a big cause of automotive deaths remains distracted driving. According to the National Highway Traffic Safety Administration (pdf download), some 33,000 deaths were caused in 2009 by drowsy driving. I don't know if there are stats yet for accidents caused by texting while driving, but I'd bet the numbers are pretty scary. That said, this stuff as well as gas are discrete from the issues raised by Lithium Ion batteries, which need to be investigated.
dbg your delayed fire comment is true and may be consedered preventable or a non-preventable occurence depending on how handeled. An informed owner may ask for and receive a knowlegeable inspection by a qualified inspector while another owner will NOT exhibt dudilligence and have a delayed fire.
Both WILL probably have insurance. Over time the actuarries will adjust the policies to reflect stupidity and real cost. Other known safety problems such as refuel explosions at gas stations are just as, or more dangerous and exeedingly more frenquent than those of eattery packs.
Good point, dgb. Consider this: A gallon of gasoline contains about 30 kWh of energy. That means that a 15-gallon gas tank holds about 450 kWh. In contrast, a Volt battery contains 16 kWh -- equivalent to about half a gallon of gas.
We still don't know enough about what happened and when we do, we will report it. But too many times, stories in the newspapers and TV news about such subjects take on the apperance of a witch hunt, then they disappear. Consider Toyota's unintended acceleration "problem." Little was written when Transportation Secretary Ray LaHood said this after the NHTSA investigation: "The jury is back. The verdict is in. There is no electronic-based cause for unintended high-speed acceleration in Toyotas. Period." And what about the infamous General Motors pickup trucks -- the ones that were profiled on NBC Dateline in a story called "Waiting to Expode?" Those vehicles, too, were supposed to be death traps...until it was learned that NBC faked the explosions with remote control explosives. Again -- I repeat -- we don't yet know what happened here. And, yes, there are anomalies. So, yes, government agencies should certainly investigate this fire (or fires, as the case may be). But until we do know anything definitive, I'm siding with the engineers. For the most part, they have a good track record.
These batteries have caused numerous product recalls including thousands of computers and just last month I got a message from Apple recalling my 1st generation, 5 year old iPod due to battery fires!! Apparently as these units aged, they have become more susceptable to initiating fires.
As with all systems, we learn to live with risk managment, by both the provider of the product and the user of the product. However, as systems become more complex, the potential failure modes increase and the reliability decreases. Just remember that the more cells you stuff in a battery and the more electronics you pack around it and its vehicles interfaces, the higher the probability of a failure.
With a better understanding of materials’ response to load and temperature, researchers could potentially use the knowledge to improve design. The research could even help geologists studying plate tectonics.
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