By on November 25, 2011

NHTSA has has opened a formal defect investigation into the Chevrolet Volt, on the grounds that

 Intrusion in a crash may damage the battery, which may result in a substantial thermal reaction and fire

We knew that NHTSA was already looking in to this type of defect after an earlier test incident, but the official investigation resume [PDF] lists three separate thermal events that have occurred as a result of NHTSA tests. Hit the jump for the official explanation of this sequence of events.

On May 12, 2011, NHTSA performed a NCAP side pole impact test, followed by a post impact rollover test on a Chevrolet Volt. In connection with that testing, NHTSA has identified the potential for intrusion damage to the battery
which may result in a substantial thermal reaction and fire. Twenty-one days after the May 12, 2011 testing, delayed thermal heating and pressure release resulted in a fire that consumed the Chevrolet Volt and three other vehicles in close proximity at the test facility.

During the week of November 14, 2011, NHTSA performed follow-up battery-level tests to simulate the incident. NHTSA performed three tests simulating the mechanical damage to a battery pack observed from the first incident. Two of the three tests produced thermal events, including fire. Because of these test results, NHTSA has opened this investigation to examine the potential risks involved from intrusion damage to the battery in the Chevrolet Volt, in coordination with the agency’s ongoing review of the emerging technology involved in electric vehicle

A more extensive NHTSA press release notes

NHTSA is not aware of any roadway crashes that have resulted in battery-related fires in Chevy Volts or other vehicles powered by lithium-ion batteries. However, the agency is concerned that damage to the Volt’s batteries as part of three tests that are explicitly designed to replicate real-world crash scenarios have resulted in fire. NHTSA is therefore opening a safety defect investigation of Chevy Volts, which could experience a battery-related fire following a crash. Chevy Volt owners whose vehicles have not been in a serious crash do not have reason for concern.

GM’s response [via Phil Lebeau/Twitter]:

The Volt is safe & doesn’t present undue risk as part of normal operation, right after a severe crash.

This is the defense that GM has been using throughout this NHTSA/Volt fire investigation, and to some extent it bears a lot of similarity to Toyota’s defense against the test results trumpeted by Professor David Gilbert. The argument is that the investigator is creating defects through conditions that would not exist in normal use. The problem with GM’s position is that the safety protocols it wants NHTSA to follow in order to not prevent these kinds of fires apparently haven’t been circulated. As GM’s spokesman put it last week

We had a process [for draining the battery] internally but I don’t believe it was shared with anyone. The incident with NHTSA raised awareness that we had to develop a procedure and alert all stakeholders.

And based on the fact that NHTSA’s press release on this defect investigation lists the agency’s tips for post-crash safety procedures for plug-in vehicles, it seems that this is its major concern. What’s strange is that GM made quite the fuss about its Volt first responder training (see video at top) when the car was launched. That this issue, and the necessary safety protocol response to it, seemed to slip through the cracks when that program was developed is not encouraging.

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32 Comments on “NHTSA Triggers “Thermal Events” In Volt Batteries, Opens Formal Investigation...”


  • avatar
    Educator(of teachers)Dan

    21 days later? Looks like the real danger is to body shop workers and scrap yard opperators, not first responders.

    • 0 avatar
      Volt 230

      Body shops won’t want to handle these cars at all, I wonder if the Chevy dealers are also gonna refuse to work on them?

      • 0 avatar
        damikco

        They would not have this problem if they follow GM’s instructions and drain the batteries.

      • 0 avatar
        Herm

        The procedure is to call GM, they send a team to drain the battery.. they need access to a car that is functional enough for them to attach their equipment.. probably takes hours and it may not even be possible if the pack got mangled enough. If you break the series connection of just one cell you cant drain the rest of the cells as a group, you have to do each one individually. I think the battery is divided into 5 modules, perhaps they can always drain the modules that are not affected.. if the wiring is intact.

        Its not easy draining a large battery pack.

        Perhaps the packs will have to be modified to automatically drain all the cells in an event.. but that would ruin the cells and make the insurance expensive. Self draining would still take a long time since you have to dissipate lots of heat.

  • avatar
    Windy

    My understanding is that regular cars are crash tested with the fuel tanks filled with water…. perhaps the electric cars should have the battery drained as well to be fair…. seriously I am amazed that proper safeing procedures to be implemented after a crash were not widely disseminated before the volt went on sale

  • avatar
    MrIncognito

    I imagine intrusion damage into a full gas tank would also produce a substantial thermal event. I don’t see how driving around with a substantial store of chemical energy in lithium cells is any different than a greater amount of chemical energy in the form of gasoline.

    • 0 avatar
      mcs

      I don’t have the numbers in front of me, but the lithium is worse. The lithium “thermal events” I’ve seen appear to be hotter and more intense than a gasoline fire.

      Edit: from the A123 Systems MSDS:
      The interaction of water or water vapor and exposed lithium hexafluorophosphate (Li PF6) may result in the generation of hydrogen and hydrogen fluoride (HF) gas.
      Contact with battery electrolyte may be irritating to skin, eyes and mucous membranes. Fire will produce irritating, corrosive and/or toxic gases. Fumes may cause dizziness or suffocation.

      If I remember correctly, hydrogen has about 2.5 times the heat of gasoline.

    • 0 avatar
      smokingclutch

      Seriously. The Vendetta Against GM continues.

      • 0 avatar
        LectroByte

        Vendetta? What vendetta? If it catches on fire at NHTSA, then to quote that candidate feller, “OOPS!”.

        Anyway, the government gave them billions to keep them in business, if that’s a vendetta, then I wish they’d start one on me.

      • 0 avatar
        Lokki

        Volt? Me vorry? They opened the investigation after 2 of 3 in the retest last week caught fire.

        http://www.signonsandiego.com/news/2011/nov/25/2nd-electric-car-battery-fire-involving-chevy-volt/?ap

        The National Highway Traffic Safety Administration said Friday that three Volt battery packs were crash-tested last week. In one instance, the battery caught fire afterward, and in another the battery emitted smoke and sparks.

        Last May, a fire erupted in the battery of a Chevy Volt that had been damaged during a government crash test three weeks earlier. Last week’s tests were an attempt to replicate the May fire.

        So yup, totally baseless vendetta against GM because a stupid 2 times out of three coincidence

      • 0 avatar
        L'avventura

        @ Lokki

        It should also be mentioned that the Nissan Leaf went through the exact same crash tests without any of their cars catching fire- Nissan’s batteries are encased in steel.

        http://online.wsj.com/article/SB10001424052970204452104577060672015346012.html

        The fact that 2 out of the 3 Volts crash tested by NHTSA caught fire means this isn’t an isolated incident. Volt’s battery should be encased in steel like the Leaf, or have a fail-safe system that would automatically shut itself off and self-discharge the battery.

        In fact, the way that the media & NHTSA has been handling these fires is suspiciously lackadaisical.

      • 0 avatar
        Herm

        The Volts battery is also encased in steel (170lbs worth).. the difference is that the Leaf pack is designed for air cooling, its a flat thin pack exposed at the bottom to the airstream.. so it air cools easier when its unpowered.. the Volt has a more square pack and depends on pumps and coolant for its cooling requirements. Perhaps once a cell shorts out in a crash the temperature rise wont be as bad in a Leaf.. in a Volt it just builds up. Maybe.

        GM went with a liquid cooled pack because it wanted to ensure the pack would last 15 years or more.. the economic life of the car.

  • avatar
    GS650G

    While we have 100 years of experience with gasoline powered vehicles in crashes, we have very little to go on with Lithium Ion batteries. It’s obvious that a tank of gasoline is dangerous, the Volt has that plus the batteries which are arguably more dangerous because they are unpredictable. New techniques are going to be required for dealing with accidents and Volts.

    As to the “vendetta” against GM I think the correct term would be witch hunt except in this case we have more than just a hard-on to justify the attention.

    Toyota has sold about a million Prius cars and we have not seen these types of problems. The media would seize on such incidents with both sets of teeth after the UA mess. Only a few thousand Volts are sold and if there is a major problem here I’d like to see GM fix it now before it turns into a real debacle. Especially since We The People still own billions of dollars of GM stock.

    • 0 avatar
      Pch101

      Toyota has sold about a million Prius cars and we have not seen these types of problems.

      Some of the early Prius models had a technical service bulletin due to leaking electrolyte. At least one fire was linked to the problem: http://articles.latimes.com/2005/nov/30/autos/hy-wheels30

      Of course, the occasional Prius may catch on fire. Here’s one that made the news: http://www.seacoastonline.com/articles/20100424-NEWS-4240319

      As I noted in a prior post, there are several hundred vehicle fires per day in the United States. Of course, most of them don’t make the news, but that doesn’t mean that they don’t happen.

      I have my own personal skepticism of the Volt, but let’s not confuse a singular incident with an epidemic, shall we?

      • 0 avatar
        Kevin Kluttz

        It’s GM. An epidemic waiting to happen. As before.

      • 0 avatar
        Pch101

        It’s GM. An epidemic waiting to happen. As before.

        You’re as bad as that Silvy guy, except for being in opposite camps.

        I’ve been critical of GM’s missteps for ages. But here, we’re talking about one individual car. A wrecked car, at that.

        There’s a difference between constructive criticism and mindless, relentless nitpicking. The former is useful. The latter, not so much.

      • 0 avatar
        GS650G

        Unfortunately (or fortunately)not enough GM Volts are on the road to gather proper statistics yet. A year from now you might find yourself agreeing with me and I won’t hold it against you.

      • 0 avatar
        tekdemon

        Doesn’t seem like they traced that Prius fire to the battery pack though and the driver reported some kind of mechanical noise issue before it caught fire. This is clearly the battery pack at fault here though and it’s the lithium ion chemistry that makes these much more prone to fire, NiMH is only fire prone if the charging circuitry goes crazy and tries to overcharge it excessively and even then it’s pretty difficult on modern cells. NiMH overheating/fire issues are something I recall being a problem in the early 90s but they’ve had a lot more time to work on making it safer whereas Lithium ion is still relatively volatile.

    • 0 avatar
      Kevin Kluttz

      Oops-wrong comment…

    • 0 avatar
      Kevin Kluttz

      It’s not a vendetta. It’s called experience with GM products.

  • avatar
    Herm

    Any crash that can breach the battery case in a Volt must have killed the passengers already.

    I hope GM/Nissan installed a thermal fuse on each cell, but any lithium cell that you crush will spark and smoke, and perhaps catch fire if it gets hot enough. I dont even want to guess what a recall would entail, probably full pack replacement.

    We all made fun of Tesla for using 7000 small cells in the Roadster, but they may end up the only one surving this witch hunt. Each cell in the Roadster is small enough not to have enough energy to damage nearby cells, and not starting a chain reaction.. plus each cell has two internal fuses and other external safety devices.

  • avatar
    NormSV650

    Looks like a High-tech lynching of GM as the readers here(the general public) know more about proper handling of a crashed Volt!

    • 0 avatar
      Kevin Kluttz

      We probably do. Not even probably. I DO know how. NEVER buy one. And GM has always done a fine job of lynching themselves. They need no help from us (except billions of our tax dollars). They have always done it. Have we forgotten that they went bankrupt from putting this crap on the roads, getting in the way of our Toyotas, Hondas, and any other car that isn’t GM (or Chrysleriat)?

      • 0 avatar
        GarbageMotorsCo.

        Don’t buy one? Why not?

        Volt sales are hot right now, so hot nobody will go near them!

        http://www.cars.com/for-sale/searchresults.action?stkTyp=N&tracktype=newcc&mkId=20053&AmbMkId=20053&AmbMkNm=Chevrolet&make=Chevrolet&AmbMdNm=Volt&model=Volt&mdId=35025&AmbMdId=35025&rd=100000&zc=02345&enableSeo=1&searchSource=TRAIL_HEAD

  • avatar

    new marketing campaign…

    Don’t be a Dolt
    Bolt your Volt
    Before the Jolt.

  • avatar
    L'avventura

    The Chevy Volt Battery is cooled when it hits 40 degrees C or less (104 F) via coolant. The problem seems to have steamed from the fact that the coolant line was ruptured during the crash which caused the car to heat up after a 21 day period.

    The design flaw in the Volt is that if the active cooling system malfunctions the car is in a high risk of fire. The Volt should have safeguards in place in case there is either a malfunction or damage to the batteries’ active cooling system. As this occurred over a 21 day period, it wasn’t spontaneous. The entire system should have automatically shut off when a malfunction in its cooling system was detected.

    For comparison, the Leaf battery is air-cooled so it doesn’t rely on coolant to cool itself. Hence, it is intrinsically designed not to rely on an active cooling system, the car merely shuts itself off if battery temperatures become critical.

    NHTSA tone in this Chevy Volt case clearly reflects the political value and liability the car represents. NHTSA blanket statement of the lack of safety of all batteries isn’t warranted as the safety of EV and hybrid battery packs is something that has been actively discussed and investigated for over a decade. Also the core cause of the fire, rupture in the coolant line, means that a situation would be dissimilar to the Leaf .

    • 0 avatar
      Kevin Kluttz

      The problem ‘stemmed’, not steamed. Just lettin’ you know. Ed, please don’t ban me. I just like good English. Sorry.

    • 0 avatar
      protomech

      “The entire system should have automatically shut off when a malfunction in its cooling system was detected.”

      I doubt the system was switched “on”. One of the damaged cells eventually short-circuited and caused a chain reaction thermal runaway in the entire pack. Turning the battery “off” means either physically separating the cells to halt a thermal runaway or de-energizing the entire pack.

      The Leaf pack gets as much cooling as the Volt pack, 21 days in storage following a crash test: zero other than passive radiant / conductive heat transfer into the environment.

  • avatar
    Kevin Kluttz

    Come on, GM. You’re up to your tried and true tricks again…using the unwitting consumer (ANYONE who has EVER bought a GM car is unwitting, by the way, myself included until my first Toyota!) as their beta testers. But now you’ve upped the ante by trying to kill them! Better look out; killing off customers has proven to be a move that could be a little disadvantageous. But it’s par for GM’s course.

  • avatar
    RRocket

    How soon until we get dire warnings from Lahood about not driving the Volt because it’s soooo unsafe? Or did he only reserve that sort of thing for Toyota?


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