The Chevy Volt cross-country Drive for Innovation is rolling south toward our next stop in Raleigh, N.C., and we've been catching up on news surrounding the Volt, its lithium ion (LiOn) battery, and charging stations -- specifically, whether the Volt is a fire hazard.
Some sites have seized on the news to push LiOn technology as a killer in the wings; others offered a tempered view, suggesting that, at least for now, it's a tempest in a teapot.
Chevy Volt in a side crash test, performed by the Insurance Institute for Highway Safety.
To recap, we know of three fires in which Chevy Volts were involved or nearby:
A fire destroyed a garage in northwestern Connecticut. The owner -- a volunteer firefighter named Storm -- had a Volt and a home-converted Suzuku Samurai EV. Here's a link to his blog on the fire, where he writes that the cause was "definitely not the Volt." (Here's a link to local TV coverage.) No cause has been determined.
In Mooresville, N.C., a fire in a three-car garage that housed a Volt spread to and destroyed a luxury home. Initial suggestions identified the 240V charging station as the possible cause. That's since been rejected, as fire officials have said the blaze started away from the vehicles and charging station. But no cause has been determined.
The National Highway Transportation Safety Board crash-tested a Volt, pushing it into a pole at 20 miles an hour. The car performed well and was stored outside in the cold. Weeks later, the car caught fire. The fire apparently was caused by a short when the punctured coolant system leaked into the LiOn cells.
The LiOn challenge
We've known about LiOn benefits and hazards since the technology's introduction. Studies and observations have been unceasing. Last decade, the FAA looked into the matter after shipments of LiOn batteries caught fire aboard or near two planes.
Small fire sources can cause big problems, as LiOn cells quickly fuse together and propagate the fire. Some traditional suppressants like Halon 1301 bromotrifluoromethane) might be ineffective; water is increasingly seen as the most effective way to put out such fires, according to a report published this spring by the Fire Protection Research Council.
Last year, a cargo plane caught fire and crashed in Dubai, carrying goods that included LiOn batteries. No cause has been identified.
Given the billions of LiOn batteries in the world, one could argue that failure incidents are marginal (how many lead-acid battery failures go unreported?).
But it's not a subject to be taken lightly. GM certainly isn't. It reported last week that it's been sending SWAT-like teams to crash events to de-energize the batteries. GM EV global chief engineer Jim Federico stands by the company's EV innovation.
Given what you know, how would you design a LiOn-powered EV to be safer? Or is it safe enough?
Story courtesy of Drive For Innovation. Design News will have additional coverage of the Volt battery issue upcoming.
For further reading
To keep up with our Chevy Volt coverage, go to Drive for Innovation and follow the cross-country journey of EE Life editorial director Brian Fuller. On his trip, sponsored by Avnet Express, Fuller is driving a Volt across America to interview engineers.
There's always an aspect to these stories where they take on a life of their own, regardless of what the facts turn out to be. A case in point is the Toyota unintended acceleration of a few years ago. The more distance one gets from that, the more it looks like driver error was the cause in a lot of so-called instances. Not saying that's the case here, but I am saying, as Brian notes, we need to wait for a full investigation before jumping to conclusions. For example, if you looked at 100 percent of charging systems for everything, you'd find some fires.
I really do not know if the LiON batteries catch fire. I find it hard to imagine that Volts randomly burst into flames, but I can guarantee that gasoline which is the alternative to batteries is higly flammable, A spark while fueling has a real chance of igniting vapors of gasoline. However, it is still common to see people smoking while filling up at the local 7-Eleven. This seems to be a case of fear of new technology showing fears that may or may not be warranted.
It was 1997 and I had just seen my very first Lithium cell pack for a cell phone.I was the Accessories Products Development Engineering Manager for the Motorola iDEN phones.We had recently migrated from the long-standing NiCd batteries to Nickel Metal Hydride (NmH) technology as a green initiative to eliminate Cadmium, but that initiative was short-lived as Lithium promised higher capacities and greater number of charge/discharge cycles, although costing a bit more than the NiCd or the NmH.500 million cell packs later, the only fires or faults we had documented were due to non-standard charging equipment; usually from a Chinese 3rd party knock-off charger that didn’t include the proper thermistors or relevant safety circuitry.Its like Nuclear Power.Follow the rules established and it will serve dutifully. I hate to see Li-Ion get a bad rap.
I have to agree with TIm that this is more likely a case of fear being raised over a relatively new and unknown technology rather than a some sort of sustainable threat. Yet it does give me cause for concern and make me wonder about additional design considerations that could help protect against the fire threat, however small. There is actually some precedent--several years back, I remember an Apple recall on littium ion battieries used in its laptops because there were reports of them catching fire. I'm wondering if there are parallels?
Am I correct in making the inference from the story and from JimT's comment that heat is the causative factor? If so, then safety is in play during driving (a well-designed battery cooling system) and can be brought into play during charging (if the rules JimT mentions are followed). So the outlier is in crashes. What can be done here? Would seem like there needs to be more protection surrounding the batteries, which means more weight, which means poorer performance (which then means you need more batteries). Similarly, poor fire protection in crashes might indicate the need for an active fire suppression system, which would also add weight, cost, etc...
Experts I've talked with suggest that the crash MIGHT have been the cause. The electrodes in lithium-ion batteries are so close together that a dent in the cell case could cause them to touch each other inside the cell, causing a short circuit. If this is the case, then a heavier battery case might be in order, as you suggest, Alex.
I wonder, though, why it would be the Volt having these problems if the root cause has something to do with the lithium ion batteries. In fact, I would think that the hybrids would then be the most dangerous since they throw gasoline into the mix. In that case you would have the normal dangers of a gas power car, compounded with whatever is alledgedly setting of these fires.
This is incredibly silly, use a little common sense. Batteries are inherently safer than a 14 gallon can of gasoline. All the examples they give are false examples anyway. They give 3 examples, 2 of which are disproved in the same sentence that identifies them. The last one was a car that survived a head on collision, and then was inappropriately driven without inspection and repair.. i.e., this article is nothing more the perpetuation of the kingdom of fear with the goal of maintaining a society who's economy is based on an obsolete energy source, fossil fuels. If you were really concerned about driver safety, and not prematurely ending any and every technology that can compeat with fossil fuels, you would have performed a comprehensive comparison of which is more dangerious, gasoline or batteries, based on likeliness of fire and severity of fire. Without question, and I do dare to request a challenge, without question, an electric powered engine + fuel containment system will always, always without question, be safe than an equivalent gasoline powered engine + fuel containment system. For example, if you were to intentionally sabotage both types of cars with the intent of inflicting the most damage, the best you could do with the electric car is start a fire and engulf the car; With a gasoline car, you could cause a massive explosion + fire. Of note, the Volt is both gas and electric, lol, so you got the worst of both worlds. Chevy = Big Oil, still refusing to give up the obsolete fuel source... killing millions every year... for nothing more than immediate profit at the cost of long term profitability and technological progress.
There's always been far too much hype around electric vehicles and lithium-ion batteries, and the recent Volt fires are no exception to that. Yes, the electrolyte in lithium batteries is a highly flammable liquid but, as Brian points out, there's nothing new about that. We've known about it for a long time. The truth is, we really don't have any reliable details on the cause of these fires, but we can definitely say this: If an improperly-constructed gasoline-burning car had burst into flames, it would have been a far worse accident, and it would have happened a lot faster than three weeks.
Three fires where Chevy volt vehicles were in the area, only one of them remotely attributed to the car, and that one was a crashed vehicle improperly stored? Does this really mean anything other than a slow-news week? Of course any vehicle that has crashed may catch fire. In most cars the battery is close to the front, both for cooling and for weight distribution. And one of the first things that a responsible responder will do is to disconnect the battery. So we know that any battery in a crash does indeed constitute a hazard. But most vehicles are never crashed, so that does not apply to them. The design of vehicles using battery power, at least those made by the aouto companies, has been one of extereme caution. All of the car companies are aware of the hordes of hungry lawyers waiting for some mistake, with the result that they have multiple layers of safety provisions in the design of these vehicles.
The external charging systems are another story, since some of them are not made by the automakers. But standard good engineering practice, in addition to the various electrical codes, plus the need for certification, assure that these systems are not fire hazards. Consider what a proven fault would do to future sales, and it is clear that the motivation to be safe is quite strong.
That leaves the installation of the charging system in the home as a potential source of a hazard. BUt then consider that most of those installations would be inspected by a municiple building inspector, and it is clear that any chance of an incorrect installation is unlikely. What remains are do-it-yourself installations by homeowners, who have unknown skill levels. That would certainly be brought out in any fire investigation, and loudly proclaimed as the cause, at least by most media. But we have not heard of any such installations being related to any of the fires.
So the logical conclusion based on current information is that non-crashed vehicles are not any greater hazard than any other ones. Now, do we hear any complaints about the hazards related to gasoline powered vehicles? Gas vapors from an open fill tube are far more likely than electrical leakage from an open battery charging door.
The author writes "fires in which Chevy Volts were involved or nearby". Then points out in the first two that the Volt was declared innocent. Then titled the article "Chevy Volt Battery Fires Arouse Investigations" -- note use of the plural "Battery Fires". If the Volts are known not to have caused the fires in the first two incidents, why bring those incidents up under the title "Battery Fires"? It seems unfair to the Volt and likely to give an inaccurate impression of guilt. You could just as (un)fairly list the nearby pavement, the Earth, the atmosphere (which WAS involved in the fires), buildings, drivers, men named Fred, etc.
I'd like to see more care taken with product reputations.
For the record, I've never owned a Chevy or an EV and have no involvement with Chevrolet or any of its divisions.
I agree with technophile about the inaccuracy of this article. I really do not think an EV will ever be anything other than a niche vehicle in my life time and have a multitude of reasons why they will not suit my lifestyle, but to focus on possible fires is ridiculous. As many posters have mentioned, we drive vehicles carrying an explosive liquid, but we should worry about a big battery. That is analogous to critcizing a politician for the size of his ears and ignoring the destructiveness of his policies.
Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
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