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Power Transportation

Days After A Fiery Crash, a Tesla's Battery Keeps Reigniting (mercurynews.com) 302

An anonymous reader quotes the Mercury News Six days after a fiery crash on Highway 101 involving a Tesla Model X took the life of a 38-year-old San Mateo man, the car's high-voltage lithium-ion battery re-ignited while sitting in a tow yard, according to the Mountain View Fire Department... The battery reignited twice in the storage yard within a day of the accident and again six days later on March 29. Two weeks later, in an effort to avoid more fires, the NTSB and Tesla performed a battery draw down to fully de-energize it...

On the company website, Tesla wrote "the reason this crash was so severe is that the crash attenuator, a highway safety barrier which is designed to reduce the impact into a concrete lane divider, had either been removed or crushed in a prior accident without being replaced. We have never seen this level of damage to a Model X in any other crash"... Tesla also reported that the vehicle's autopilot function was active at the time of the crash...

The National Transportation Safety Board is investigating the Highway 101 crash and three other accidents also involving Teslas, including a fiery 2014 Model S crash Tuesday in Florida that killed two teenagers. Also under investigation: A Model S crashed into a fire truck near Culver City in January, and the driver reportedly said Autopilot was engaged at the time. And it is looking into a battery fire of a Model X that drove into a home's garage in Lake Forest in August.

Two hours after that story was published, a Tesla smashed into a Starbucks in Los Gatos, California.

Days After A Fiery Crash, a Tesla's Battery Keeps Reigniting

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  • by Type44Q ( 1233630 ) on Thursday May 10, 2018 @11:14PM (#56592878)

    The desperate schmucks who've shorted Tesla would love nothing more than another headline but the implication here (that Li-ON is even less stable than some of us may have realized) affects Tesla only indirectly... and effects their [viable, prospective] competition equally.

    Eyebrow raising but otherwise changing nothing.

    • (that Li-ON is even less stable than some of us may have realized)

      Even less stable? Given it's a car, the point of comparison is petrol. I mean sure, they don't tend to re-ignite days after but that's only because once they ignite at all they go so fast there's nothing left to reignit ever.

      Back to the battery though, LiPo are known to be fragile and I'm surprised as to how resilliant the Tesla battery packs have proven.

      • You probably shouldn't be all that impressed considering how lithium batteries, like most things that can burst into flames, need oxygen to do so and with the way Tesla puts them together with spot welds they're pretty airtight until you get into a very high energy crash. I say high energy and not high speed because a slower crash with a very heavy vehicle, like say a train, can create an as much if not more damage than a much higher speed crash simply due to the laws of physics (E = mv^2 you know).

        That
        • ...so that emergency services and the people who recover cars that have been in serious accidents can remove the fire hazard (it's the energy in the battery that is the source of energy in lithium battery fires) by simply discharging the battery into the ground.

          You know that would take hours, right?

          • If it takes less than 30 minutes to go from about 20% to about 90% using a supercharger station I can't imagine it'll take all that long to do the reverse with just high grade metal wire (say a lighter version of what they use for power lines) straight to ground. If you're doing really high speed semi-uncontrolled discharges it should obviously be delay or remote triggered, but I can't imagine it being more than 20 minutes to completely discharge the battery to the ground safely in most cases.
            • by msauve ( 701917 )
              "discharge the battery to the ground?" You might want to Google around about electricity. It doesn't work that way.
              • Where do you think the ground pin in your electrical outlets goes? Or any earthed electrical system for that matter?

                I somehow get the feeling I'm arguing with just a very low effort troll...
                • by dfghjk ( 711126 )

                  No, you're just an idiot. The ground, i.e. the earth, has nothing to do with discharging a DC battery.

                  If you shorted a battery with "high grade metal wire" you'd rapidly cause the fire you were trying to avoid, that's assuming protection circuits don't interrupt the process and defeat the discharge entirely. You have to use a load designed to discharge the battery within it's operating parameters and that load has nothing to do with an earth ground.

                  I don't believe you're so much a "cynical critic" as an "

                • by msauve ( 701917 )
                  My water pipe goes into the ground, too, but I don't expect to get electricity out of the faucet. Seriously, you lack an understanding of even basic electricity.

                  Simply, a battery has two poles, positive and negative. To draw power out of a battery, you connect an electrical load between the two poles.

                  There's no ground involved at all. That's why you can carry a cellphone around and it doesn't need to be grounded. It's why an electric car works even though it's electrically insulated from the ground by
        • by Rei ( 128717 ) on Friday May 11, 2018 @07:20AM (#56594354) Homepage

          That said, with the amount of energy that's stored in electric car batteries

          Electrical energy stored != combustion potential energy, and combustion potential energy != energy that can be practically released in normal circumstances (there's five times more potential energy to be released from the combustion of 1000kg of alumium or graphite vs. 1000kg of nitroglycerine, but which one would you rather be next to in a crash?).

          It is not the "energy" stored in the batteries in "lithium battery fires" as you put it. First off, they're lithium-ion batteries, not lithium batteries, and yes, there's a big difference. There's no metallic lithium in lithium-ion batteries unless they've been abused (plating out of lithium at the anode is a failure mode, due to attempting to overcharge a cell or charging at too low of temperatures - both of which are prevented in a proper EV battery pack). The power (not energy) of the cell may provide a (significant) short-circuit ignition source if crushed, but what happens thereout depends on the chemistry of the cell; the fire from a burning cell (in varieties that are capable of burning) is most often the electrolyte (of which there are many varieties). The rest of the cell just isn't that flammable; the anodes are predominantly carbon (graphite or amorphous, sometimes with silicon) and the cathodes are metal oxides. The lithium itself is present as ions (hence the name) intercalated (in small quantities) in the lattices of the graphite and metal oxides.

          What happens in a battery pack, however, is a bit different from an isolated cell. In a ruptured, internally-short-circuiting cell in a battery pack, the heat and contents are released, but they're released into non-flammable temperature-regulated pack coolant. Aka, quenched. Packs also employ a variety of processes to physically isolate cells from each other. Normally, cell failures are self-extinguishing in a pack. The problem with this accident is that it was so energetic that it utterly mangled the battery pack. Which is hard to do, as the pack lies within the wheelbase, but "high speeds into a concrete barrier" is a huge amount of impact force. When storing this pack, there was almost certainly no coolant left, and a lot of damaged cells. Yes, the remaining charge was an ignition source, but it's not what you see physically burning; on its own, a short circuiting cell just makes itself very hot. Anything that happens after that is a result of the consequences of that heat - and more specifically, the results of that heat on the electrolyte.

          Tesla will need to adjust the storage procedures for such heavily damaged wrecks. This appears to be the first case of reignition days after extinguishing in the company's history, but it'll need to be accounted for.

          Either way, the rate of EV in general (and Tesla in specific) fires is much less than with ICEs.

      • by AmiMoJo ( 196126 )

        They usually drain the liquid fuel after a serious accident. Seems like discharging the battery in similar circumstances might be a good idea.

        • by Rei ( 128717 )

          I'd think that one of the biggest challenges would actually be one of the safety features - the pyro fuse. It blows instantly in an accident, disabling all discharge.

    • (that Li-ON is even less stable than some of us may have realized)

      what ? who youldn't ?
      where they born after the 2000s ? Weren't they paying attention with the Samsung Galaxy recently ?
      If anything, Sony's problem with bad quality batteries back them (and reconfirmed recently with Samsung) would have told us already that battery LiIon/LiPo battery have a certain tendency to blow up whenever you look wrong at them.

      Disconnecting and removing Lithium battery from a damaged device should be standard practice.

      And if a Tesla car had such a violent crash that the battery pack int

      • Disconnecting and removing Lithium battery from a damaged device should be standard practice.

        The problem is that the car is basically built around the battery. It is installed into the vehicle partially with adhesives, which is why Tesla probably never actually swapped a single customer battery. (They didn't actually swap the battery in their stage demonstration, either; Tesla has literally never shown a single battery swap.) It's extremely nontrivial to remove the battery at all, and what happens if it bursts back into flames while you are removing it? The chance for harm to the disassembler is ma

        • The problem is that the car is basically built around the battery.

          I agree, we could even say, that you basically are buying a giant battery from Tesla, and for that price, they throw in a car bolted on it for cheap.
          (Given the relative price).

          It's even more noticeable with manufacturer where the car and the battery can by sold separately (e.g.: Renault - the 45kWh battery costs around 10k EUR)

          It is installed into the vehicle partially with adhesives,

          Maybe in the latest models? (the platform used to build model 3 upon, maybe ? I haven't been following that in details)

          But older platfroms where designed with battery swapping in min

          • Did they do an actual full blown battery swap ? Probably not. (Elon doesn't even mention how the disconnect/reconnect the batteries from the liquid cooling loop. Redundant Zero-spill Quick-disconnect valves, perhaps ?)
            But they proved that it's not impossible to unscrew and re-screw the battery from underneath (using the same type of screwing robots that mounts batteries and cars together in the factory).

            They proved it was possible with a specially-prepared car. Anyway, battery swaps are dumb, batteries are getting better all the time. The focus should be on safety and charge time now.

  • by jschultz410 ( 583092 ) on Thursday May 10, 2018 @11:33PM (#56592968)

    In any accident that hurts the integrity of the batteries, then they should be drained as standard operating procedure.

    If a gas tank was leaking, then would they just let that go too?

    • Exactly.

      I've been waiting for a barrage of "Killer Tesla" stories ever since it started to look like the people with a short position on Tesla stock were going to take it up the pooper again.

      • by Rei ( 128717 )

        I remember all the people over in Shortsville writing articles encouraging people not to "go wobbly" when Tesla was down in the 250s/260s, but to double down on the shorts.

        $306,85 today ;) And analyst factory checks showing that production appears to be up to nearly 3k per week now. Now you've even got long-time Tesla-despising shorts going long [thestreet.com] just to cash out on the squeeze of their fellow shorts. It's going to be a $10+B bloodbath.

        Now that their old production canard is going away, they'll have to re

    • Re: (Score:3, Insightful)

      by vtcodger ( 957785 )

      "In any accident that hurts the integrity of the batteries, then they should be drained as standard operating procedure"

      Safely "draining" 50 or more KwH of electricity is likely to be a non-trivial job. Especially if the battery is damaged and may have a few broken ground/power connections. You can drain gasoline or diesel into a metal tank. Electrons, not so much.

      • "You can drain gasoline or diesel into a metal tank" - providing there are no holes from accident damage (or rust in an old vehicle) in the tanks to be drained or you'll be standing in that flammable liquid
      • You can drain gasoline or diesel into a metal tank. Electrons, not so much.

        Unlike gasoline or diesel, which can still ignite after being drained from the tank, electricity is pretty much harmless once you've discharged it into a ground, like say the ground. Only danger is that people who really don't know what they're doing may put themselves in the electrical path between the battery and the ground, but the thing about current is that it will always take the path of lowest resistance to ground, meaning that it's easy to create procedures for this that are pretty much foolproof.

        • Elecrticity does not work like that. You seem to think it acts like a substance.

          • What part of my explanation assumes it acts like a substance and not just a whole bunch of electrons stored in the battery material that just needs to be allowed to migrate away from the battery material? I thought using a high grade metal wire of some kind for this was kind of obvious... This isn't a regular news site for the scientifically and technically illiterate after all.

            Sure, I could have explained the electrocution risk in terms of people making themselves part of the circuit from the battery to
        • by sphealey ( 2855 ) on Friday May 11, 2018 @07:18AM (#56594346)

          = = = Unlike gasoline or diesel, which can still ignite after being drained from the tank, electricity is pretty much harmless once you've discharged it into a ground, like say the ground. = = =

          There's a pretty common belief, probably stemming from how we are taught about electricity in 2nd and 3rd grade, that Gaia maintains reservoirs of electrons and positrons at the Earth's core and that electricity will "seek a path to ground", presumably to be stored in this reservoir for future deployment by the various gods/goddesses of lightning, the ghosts of Edison, and Tesla, etc. This is to put a fine point on it not true; if you connect a Tesla battery 'to the ground' (presumably by sticking some sort of metal toothpicks in the nearest soil and connecting the battery leads to it) at best you will get some slightly warmer soil in the vicinity of those toothpicks while the battery pretty much holds its original charge. The emergency services would have to carry around 1 MW resistors to use as the energy sink, and those things are not small or cheap ( http://www.jovyatlas.com/ja/Te... [jovyatlas.com] )

        • by hey! ( 33014 )

          I'd guess the trick is not causing creating hazardous conditions in the battery. It doesn't matter how fast you drain a gas tank, but draining a battery quickly will create heat at the point of greatest resistance.

          Presumably the batteries and cells have short circuit protection that prevents you from draining it faster than is safe when it is intact. But the safe discharge rate might be considerably lower for a severely compromised battery.

        • I'm the world's worst physicist, but I think 50kwH works out to about 300 million joules. If I have that right, that's the equivalent of three sticks of dynamite. Unless we've repealed Conservation of Energy, all that energy has to go somewhere when we "drain the battery". I'm quite sure that can be done safely, but getting rid of it without damaging the drainer is likely a problem.

          One may also need to limit the discharge rate to keep the battery -- which has design limits -- from either exploding or (mo

      • Safely "draining" 50 or more KwH of electricity is likely to be a non-trivial job. Especially if the battery is damaged and may have a few broken ground/power connections.

        The battery pack should be designed for this, assuming it isn't already.

        You can drain gasoline or diesel into a metal tank. Electrons, not so much.

        You can drain electrons "into" a carbon rod. That's even cheaper than a metal tank.

  • by Anonymous Coward on Thursday May 10, 2018 @11:51PM (#56593032)

    Can someone please provide a car analogy?

  • by tempo36 ( 2382592 ) on Friday May 11, 2018 @12:11AM (#56593090)

    The battery catching fire is an interesting point. I'd be interested to know if the emergency responders initially followed the published guidelines for cooling the battery or if they stopped when they stopped seeing flames. Regardless, it's an interesting point and an important one for the future.

    Regarding the rest of the OP's posting...yeah, 2 teens died in a Tesla in Florida while speeding 50-60 around a corner marked for 30 mph. Yes, a lady crashed her car into a Starbucks. Where are the headlines about some random kid who died in a pickup truck this weekend? I'll bet you $50 it happened. Or the old lady in her Ford Fiesta who ran into a parked car? I'll put $20 on that one. What, no national headlines on those ones? What gives? Or do we think miraculously owning a Tesla makes you immune to being a stupid/careless/human driver? I didn't know Musk was advertising that feature. Is Ford? Honda? Lexus?

    • I agree with you, 100%. However teslas are for the rich, we can't afford them, so i can see why they get picked on. Kind of like people who total their lambos. Usually makes the regional news at least.

      A more important factor is probably that It is new tech. Do you remember how many creepy, misinformed FUD articles about the internet we had to endure all throughout the 90s? The internet was abducting your children, making their minds goo with extreme violent video games, seeing pornography, and hacking the p

      • I agree with you, 100%. However teslas are for the rich, we can't afford them,

        Speak for yourself. Some of us can afford a Tesla.

      • I agree with you, 100%. However teslas are for the rich, we can't afford them, so i can see why they get picked on. Kind of like people who total their lambos. Usually makes the regional news at least.

        People who think Teslas are "for the rich" and are "Like people [sic] with lambos" are confused about price tags.

        A Tesla S starts at $75k. Ceiling around $140k.

        A Lamborghini starts at $200-250k and just goes up from there with practically no ceiling (ok, of course there is...but it's high).

        Yes, for some folks $75k might as well be $1M for all it matters to them, but there are tons of cars in the $75-90k price bracket, so pinning Tesla as some kind of super rich person toy that is deserving of some special m

      • Worth mentioning that every car today has a giant tank of energy. A gas tank is in no way safe.
    • by Gravis Zero ( 934156 ) on Friday May 11, 2018 @01:28AM (#56593304)

      So where's the "Honda crashes into bus!" stories?

      Right here [arcpublishing.com]

      Where are the headlines about some random kid who died in a pickup truck this weekend?

      Oh please! He didn't die in the pickup truck. [pdccourier.com]

      Or the old lady in her Ford Fiesta who ran into a parked car?

      Apparently, not a lot of old ladies drive a Ford Fiesta... but when they do, it's epic. [daily-chronicle.com] ;)

      • So where's the "Honda crashes into bus!" stories?

        Right here [arcpublishing.com]

        Where are the headlines about some random kid who died in a pickup truck this weekend?

        Oh please! He didn't die in the pickup truck. [pdccourier.com]

        Or the old lady in her Ford Fiesta who ran into a parked car?

        Apparently, not a lot of old ladies drive a Ford Fiesta... but when they do, it's epic. [daily-chronicle.com] ;)

        Hah. I'd hug you if I could. You rock.

        • Hah. I'd hug you if I could. You rock.

          Huh. That's an interesting response. Usually when I give people links to stories about children dying, people tell me that I'm "sick" and to "get help". Glad to see I'm winning you people over. ;)

    • Some firefighters at least do get formal training in handling chemical spills, etc. But I imagine that it's difficult to keep the training materials up to date when technology changes. And I'm not sure what tools your local Pumper unit is supposed to use to "drain" a Tesla battery. Somehow a ax or firehose seem unlikely to be a proper fit to the problem.

      • by sphealey ( 2855 )

        Searching electric vehicle ems training brings up quite a few resources from DOE, NFPA, and many other organizations. 15 years after the widespread introduction of the Prius as the first modern electric car to sell in large volumes I expect all certified safety organizations have procedures in place for handling electric vehicle accidents.

        Here's a good summary from the DOE: https://www.energy.gov/sites/p... [energy.gov]

    • The battery catching fire is an interesting point. I'd be interested to know if the emergency responders initially followed the published guidelines for cooling the battery or if they stopped when they stopped seeing flames.

      As far as I've understood, the crash was this time so violent, that it damaged the integrity of the battery pack.

      There might still be some conductors shorted by the deformation here and there, in such was the thermal fuse wouldn't break.
      The shorted cell keeps warming and eventually get hot enough to burst into falme re-starting the fire.

      A damaged battery on any gadget (not only specificially electric cars) should be considered as a potential hazard and should immediately by removed and put in a secure place

    • The battery catching fire is an interesting point. I'd be interested to know if the emergency responders initially followed the published guidelines for cooling the battery or if they stopped when they stopped seeing flames. Regardless, it's an interesting point and an important one for the future.

      Regarding the rest of the OP's posting...yeah, 2 teens died in a Tesla in Florida while speeding 50-60 around a corner marked for 30 mph. Yes, a lady crashed her car into a Starbucks. Where are the headlines about some random kid who died in a pickup truck this weekend? I'll bet you $50 it happened. Or the old lady in her Ford Fiesta who ran into a parked car? I'll put $20 on that one. What, no national headlines on those ones? What gives? Or do we think miraculously owning a Tesla makes you immune to being a stupid/careless/human driver? I didn't know Musk was advertising that feature. Is Ford? Honda? Lexus?

      Where are the headlines about those other Tesla stories you're complaining about? Because I sure didn't see them here on slashdot. The first I heard of them was as valid context provided to this story, which is a pretty standard practice.

      This story is news and headline worthy, because it shows that an EV battery in a crashed vehicle is more dangerous and volatile that people realize, and it requires special equipment and expertise to deal with. Right now I'm wondering about the life-cycle of these batteries

  • The era of the self-crashing car.

  • I am not Musk fanboy. If a smug and undeserved air of superiority would solve the issue, Tesla would have no problems at all. But this is hardly a Tesla-unique problem, and electric car using li-ion batteries is likely to have the same problem. This seems more like a problem with the wrecker service or scrapyard. You wouldn't leave gasoline-powered with a leaking full tank sitting around hoping it something didn't cause a spark, in fact the first thing you do is take out the (lead-acid) battery and drain th

    • > electric car using li-ion batteries is likely to have the same problem

      Even RC cars, I have seen small LiPo pack catching fire, it's impressive, even a small 2S the size of a cigarette pack can burn down your house. Lot of video on youtube of battery fire.

  • ...with Samsung. There are interesting sinergies for unconventional battery applications.
  • Until the car reignites again, just to spite people wanting to put it's fire away.

  • The reason the crash was so severe was because that fucking tree wouldn't move out of the way.
  • by 140Mandak262Jamuna ( 970587 ) on Friday May 11, 2018 @08:10AM (#56594526) Journal
    Tesla is fast approaching 200K cars delivered in USA, let us round it up and call it 125 K on the road since 2018 Jan

    There are 100 million ICE cars on the road in USA. And NTSB reports there are 500 vehicular fires that kill 100 people every day.

    Since 1 on 800 vehicles on the road are Tesla, we should expect around 0.625 Tesla fire every day or about 18 fires a month or 60 Tesla fires in the first quarter of 2018.

    Since every Tesla fire gets national news coverage, I would assume at most two fires happened in that period.

    I would conclude Tesla prevented 58 vehicular fires in the first quarter of 2018.

    • by ledow ( 319597 )

      Skewed by:

      - Vehicle usage ("vehicle" includes long-distance trucks, motorbikes and all sorts, Tesla only really make cars)
      - Journey distance (cars can do three times the distance of a Tesla, so are used for different things)
      - Vehicle age (adjust for 15-year-old falling-apart things with rusted mounts for fuel lines, etc.)
      - Other causes (e.g. deliberate arson)

      Hell, most Tesla in the UK wouldn't have even had their first MOT test yet. They'll still be inside the service warranty. They are literally not old

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