Fail of the Week: How Not to Electric Vehicle

If you ever doubt the potential for catastrophe that mucking about with electric vehicles can present, check out the video below. It shows what can happen to a couple of Tesla battery modules when due regard to safety precautions isn’t paid.

The video comes to us by way of [Rich], a gearhead with a thing for Teslas. He clearly knows his way around the EV world, having rebuilt a flood-soaked Tesla, and aspires to open an EV repair shop. The disaster stems from a novelty vehicle he and friend [Lee] bought as a side project. The car was apparently once a Disney prop car, used in parades with the “Mr. Toad’s Wild Ride” theme. It was powered by six 6-volt golf cart batteries, which let it maintain a stately, safe pace on a crowded parade route. [Rich] et al would have none of that, and decided to plop a pair of 444-cell Tesla modules into it. The reduced weight and increased voltage made it a real neck-snapper, but the team unwisely left any semblance of battery management out of the build.

You can guess what happened next, or spin up to the 3:00 mark in the video to watch the security camera mayhem. It’s not clear what started the fire, but the modules started cooking off batteries like roman candles. Quick action got it pushed outside to await the fire department, but the car was a total loss long before they showed up. Luckily no other cars in the garage were damaged, nor were there any injuries – not that the car didn’t try to take someone out, including putting a flaming round into [Lee]’s chest and one into the firetruck’s windshield.

[Rich] clearly knew he was literally playing with fire, and paid the price. The lesson here is to respect the power of these beefy batteries, even when you’re just fooling around.

91 thoughts on “Fail of the Week: How Not to Electric Vehicle

          1. Not quite. There are safer chemistries – what Tesla uses happens to be the cheapest kind that also has high power and energy density. The safer ones are more expensive and less powerful.

  1. I don’t even charge 2s cell packs without being in view of them at all times and using a dedicated charger. These guys just plugged them in without any balancing system (and probably no constant current source either). Great advertising for ‘Advanced Technologies’ :))

    1. had a 2s lipo for rc car go up in my basement. 80k$ worth of damage later…

      Not a single smoke detector went off, and luckily it self extinguished as we were all asleep (I forgot I had put it on to charge!)

      Still waiting on my insurance company to rebuild 6 months later.

      1. I have one “LiPo Safe” bag per LiPo after one was bloated. Thankfully it was fully discharged, so I threw it out. Then I saw a couple Mobius cameras and had the realization that the LiPos were sitting there bloated too. Took a solid MONTH to discharge thoseti things!!! Now I’m just glad the only LiPo I have left in the house is a Fatshark one with battery status indicator, currently in a bag.

        Use a single LED should one get bloated on you. Small breadboard can help with stripped wires and such if need be. No resistors. Once the LED is entirely unlit (use a clear one to be sure), it’s good to throw out. Read that tip somewhere. Then you can keep the LiPo Safe bag for another one!

        I’m trying to get a different kind now entirely. LiPo doesn’t do me any favors. Lion might be better for RC cars and such, I need more shelf life longevity and safety than squeeze-out-the-last-electron performance.

      1. Hey check it out youtube, I made a DIY powerwall! It’s just a bunch of nitroglycerin shoved in between two studs. I put it right next to my sound system for optimum power delivery.

      2. – Yep, what a joke… Thought they looked like they might be interesting at first, but ‘cheap diy powerwall’ = shove a bunch of cells in a box, with no BMS, charger, or inverter, spend almost as much on a graphics on a glass cover plate as the rest of the build to make it look cool, and call it a tesla powerwall. And heck, do it with recycled recovered cells while you’re at it, so you’re even more up a creek with no balancing or BMS…. Man, I hope nobody is trying to reproduce those builds.

        1. They do, unfortunately. Where I live it was in the newspapers a few months ago. A freak built a “powerwall” in his basememt with thousands of lithium cells and, of course, it went off. They had to evacuate the whole block because of the toxic smoke. IIRC more than hundred people had to leave their homes. Thank God nobody got seriously hurt.
          Lots and lots of fun with the insurance companies for sure!

      3. It’s like JBOD arrays, but for batteries!
        How about we coin it “JBOB”, for “Just a Bunch Of Batteries”, no management, no balancing, no overcurrent or over/undercharge protection, nothing. Just a bunch of batteries.

  2. Wow! I guess those cells were not of the safety-chemistry types and presumably because of the required power delivery demanded of the cells.

    The e-bike batteries I got seem to have safety cells in them as I’ve lost a battery pack in a crash leaving crushed shorted cells but all intact and has not ruptured into flames. Then again the bike only needs 1KW max thus draws 2C.

    Hopes they’re able to recover from this with luck of gaining another project platform to have fun with taking in the lessons learnt.

    1. Li-ion and li-polymer are high capacity but absolutely needs a safety BMS.
      Lifepo4 got a lower capacity and voltage, but seems to handle abuse better and somehow got a higher cycle count.

      1. And higher self-discharge.

        BMS can’t stop a battery fire, it’s just there to prevent overcharging. Tesla batteries employ NCA cells, which have a thermal runaway limit at 160 C, where they pretty much self-ignite. Any reason to get them that hot, and they will go.

        There was the one car in France with a badly welded tab on a cell; they took it out of the dealership for a test drive and couple kilometers later it caught fire because the faulty connection heated up, heated the cell, which then caused a chain reaction in the module.

        The trouble for Tesla is that they’d need to add so much mass to the battery to isolate the modules well enough that they won’t ignite each other – they just choose not to, and cross their fingers for good luck that more cars don’t burn down.

        1. Tesla uses liquid cooling for their batteries. Since the battery also gets warm while discharging the cars don’t need to use electricity for running a range sapping resistance heater in cold weather, at least not unless it’s really cold.

          1. The battery discharge efficiency is too high to provide meaningful cabin heat, which requires a couple kilowatts. That would be a significant energy loss, and it takes a long time to get it when you have 450 kg of batteries to heat up first before you get hot air out.

            The battery cooling system is designed to keep the cells in the charging window (0 – 40 C) which is required to avoid damage and excessive wear on the batteries.

  3. Nice demonstration video how to NOW use fire extinguisher. Mistakes: a) dont wait. Most probably if he had used it indoors rest of batteries did not explode. b) you must use it from close distance. Yes if there is explosions it can be dangerous. And after all first mistake was when they buy their extinguishers. If they do not want mesh then do not buy powder ones. Buy co2 model. Specially when you play with lithium batteries CO2 extinguishers save your day.

    1. CO2 extinguishers are awesome but they can explode too. There were few explosions in my country during summers one happened at my university because an idiot moved cart with two extinguishers to the spot exposed to direct sunlight. IIRC one student was killed few other people were injured.

      1. Compressed gas tanks (like CO2 extinguishers) are *supposed* to have overpressure rupture disks, to prevent just this occurrence. The tanks are also supposed to be pressure tested every 5 years (or is it 3?)

    2. Fire extinguishers largely work by removing the source of oxygen to the burning material. I don’t think those cells were dependent on atmospheric oxygen for their pyrotechnics. (In the same way as an actual pyrotechnic isn’t)

    3. A charged lithium battery has elemental lithium present in the carbon anode – CO2 won’t help anymore then water, it’ll probably even be worse then water, as it can’t draw away so much heat as water can…
      Once you have cells in thermal runaway, only solution is to cool the neighboring ones, so that they don’t join the party.

      Only problem is you need a LOT of water, far more then a garden hose can deliver.

        1. Absolute temperature isn’t a good metric you have to account for the heat capacity of the material and how well it absorbs the heat from the material you’re trying to cool. Water for example has a specific heat 6x better than CO2 per kg at STP. CO2 will also rapidly expand so a majority of it won’t even come into contact with the burning cell. That’s fine for a normal fire because the whole point is to limit the availability of oxygen to the fuel not to cool the fuel down lithium fires act differently though.

        2. And the thermal capacity of the entire fire extinguisher is worth how much water? You don’t need to freeze the cell, just keep it below 160°C in order to keep it from taking off.

    4. You cannot use any fire extinguisher on Lithium-ion batteries at all. FULLSTOP If you think, you are wrong.
      The Lithium is a material that have an exothermic chemical reaction without the need of any external O2, which you would reduce with a fire extinguisher. The O comes from Metal-oxide within the battery itself. There is no fire extinguisher that would help.
      With a lithium battery your only option is a controlled burn down. That is also what the fireman are doing. The water used for the controlled burned down is more for cooling down the place, then for removing O2. With a CO2 fire extinguisher you have absolutely no cooling down effect.
      CO2 extinguishers will NOT safe your day with Lithium-Ion Batteries.

        1. Doesn’t matter. It hasn’t got enough mass flow to remove enough heat to stop the reaction.

          Lithium burns in CO2, so blasting a CO2 extinguisher at a raging battery fire is like trying to put down a forest fire by pouring very cold gasoline on it.

      1. It’s been said before, but they were not trying to extinguish the fire. You’re completely right, you can’t stop a thermal runaway in a lithium ion battery. However, you can prevent other cells from heating up too much by cooling them down. A CO2 extinguisher certainly has a cooling down effect, but only at close range. It is, however, far less efficient than water.

    5. CO2 doesn’t work on these sorts of fires. A foam extinguisher might have worked better and would have allowed to discharge indoors without worrying about damaging other things. I can totally understand not wanting to set a powder extinguisher off inside, that stuff is NASTY and very hard to clean off. It could do serious damage to the other cars in there without it being immediately visible.

      I don’t understand why people buy powder extinguishers. The collateral damage they cause can far outweigh the damage of a small fire and there are better alternatives available. They’re just more expensive

    6. I liked the way he blew on it, like a birthday candle…

      Think they kept some distance, because it was tossing burning battery cells, like roman candles. The should do the next one at night, maybe New years eve…

  4. It seems to me that the power in these cells mean that whatever the reason for starting you are not going to stop it. Removing the oxygen by using CO2 may stop it in the early stages but it will just start again if the cells are at temperatures near their leakage temperature and pressure.

    Using a water hose on Lithium, as the firemen did, also seems to be somewhat suspect.

    This may initially be a lack of forethought or stupidity but I bet it is not the last. Fires like this will become common place once electric cars start having accidents and no amount of marketing material is going to make me think otherwise.

      1. Plus a swimming pool to submerge it in to ensure proper cooling I’m guessing?

        Wasn’t there a report of a crashed Tesla catching fire in the recovery yard days later somewhere?

        These big lithium batteries really do concern me.

        1. That’s something that people will have to become accustomed to handling. A recovery yard presumably wouldn’t accept a car with a leaking fuel tank without some special considerations, likewise it shouldn’t accept a car with a damaged battery without special considerations.

          1. The difference is that it takes just a Makita drill, a funnel and some jerrycans to properly ‘discharge’ a leaking gasoline fuel tank.
            A damaged 100kWh-Battery is much much more dangerous and difficult to handle.
            My opinion.

          2. Unfortunately, leaking petrol tanks are far easier to spot and petrol fires are easier to put out.
            A damaged battery pack may not show any external signs, and certainly can be detected by smelling petrol or spotting a drop on the driveway.

      1. In a fully charged battery, the lithium is bound to the carbon anode. When the battery discharges, the lithium migrates to the cathode and forms lithium-cobalt-oxides. LiC6 is very very flammable because the Li+ ions are very loosely bound and come out at any chance to react with oxygen.

        You pour water on LiC6 and it starts puffing out CO, H2 and tons and tons of heat.

        1. The standards say that Class D (dry) extinguishers are required for primary lithium battery fires (which contain metallic lithium) but they are *not* required for lithium-ion battery fires and water is recommended. That tells me either there’s not enough LiC6 to matter, or it’s not reactive enough with water to cause a runaway reaction.

          1. *sigh*. Better throw out all this salt, it’s full of sodium and chlorine and will explode and poison me if I add it to water!

            Lithium metal and lithium ions behave *very* differently.

    1. Lots of water is apparently the best way of dealing with lithium battery fires – takes away the heat rapidly enough to stop it spreading to the rest of the cells. It’s also slightly conductive, of course, but that’s the least of your worries at that point.

      1. Liquid nitrogen is pretty much the only thing that really puts it out, but the fire starts again as soon as the nitrogen disperses. The point of the water is to burn the lithium off, with enough water to soak up the heat.

  5. Australian fire fighters don’t even bother with the car, they just hose down the surrounds and wait for it to burn out while restricting traffic. We’ve had a few go up around here for unknown reasons. I’m blaiming the hoop snakes nesting in the battery packs.

    1. Well almost everything. They didn’t charge those batteries properly. At all. They also risked their own well being quite a bit for the sake of the much more replaceable (and probably insured) property around them, but I guess that’s their own choice.

  6. This article is put up using a video that already had a followup and that is not mentioned. He also never faults Tesla or their battery pack in the original video. He assumed everybody could see they were charging it and did not use proper procedure. This is all explained in the follow up video. This article is making cheap sensation where none should exist. They “abused” the battery and they showed the results as a warning to people doing the same. Nothing wrong with that.

    1. Proper procedure might have avoided -this- accident, but the video still shows what firecrackers the Tesla batteries are.

      They are not safe in any sense, which is why Tesla is developing the NMC battery chemistry with Panasonic to replace these NCA cells. Problem being that the NMC cells are more expensive and have lower charge/discharge rates so you don’t get the 2.5 second accelerations (or supercharging) with them.

      1. Have you ever heard of this thing called gasoline? It’s a real firecracker too, especially if you handle it like these morons.

        Faulting Tesla for this is ridiculous, and I’m not even an Elon fanboy. Anything that holds enough energy to move a car over 300 miles in a small space is going to be dangerous. You can’t blame them for physics.

        1. Batteries are inherently different from gasoline in the same sense as how gunpowder is different from powdered carbon.

          One requires oxygen to burn, the other has its own oxidizer built-in.

          1. I like your analogy, and wonder where Diesel fits in?
            We had a big messy car fire at work. The fire caused a lot of damage to the car, the extinguishing system caused a lot of damage to the test cell, mainly lots of insulation got soaked and needed to be replaced. (It wasn’t one of our cars, even, it was a rival manufacturer using our facility).
            The cause of the fire wasn’t a fuel leak, or even a brake fluid leak, but a _coolant_ leak. With a diesel the fuel is only the third most flammable liquid in the engine bay (after brake fluid and coolant)
            Interesting article on the subject here: http://garrett-engineers.com/cases-of-the-month/what-auto-fluids-burn/

  7. Why use CO2 on a thermal runaway fire? Isn’t CO2 burning up our planet? Seems like spraying CO2 on a fire, would just trap the heat, and make it burn better. Wonder, what’s the carbon-footprint of a CO2 extinguisher?

  8. Once the lithium battery starts burning you have few options other than wait for ot to finish. Your job at that point is to safely contain the fire.

    For battery testing of uncertain cells i keep a bucket of play sand handy. The battery that is probably going to burn is burried in sand which keeps flames from catching the surroundings on fire.

    1. I was wondering if throwing a welding blanket over the battery pack would have helped contain the fire? I’m sure the blanket would burn up eventually as most are only rated to 1000F but it may help contain the flying debris and heat until you can flood the pack to cool it down.

      1. Or make it hotter.

        One issue about smothering a fire like this is that the chemical fire is going on regardless, and it’s emitting flammable gasses like hydrogen and carbon monoxide, which collect up under the blanket. You can put it out for a moment, but it’s coming back with a vengeance.

  9. The car can be salvaged. Didn’t even completely burn through any of the plywood body panels. Use them for templates to cut replacements. Probably have to replace heat weakened parts of the frame. The rear axle may be toast too.

    Putting a Tesla drive unit in it would be very stupid. Not at all safe. The torque would rip the wood spoke wheels to toothpicks.

  10. Lithium battery fires have been common for a couple decades now, surprising still some people unaware of the hazards. It’s also odd that someone who owns/works in a shop wouldn’t be more concerned about safety. You have your business, tools, and equipment to be concerned about. He was concerned enough to install security cameras, seem reasonable to expect that he read a few things about lithium battery packs. He also has other peoples vehicles in the shop, insurance, and a business license. Safety, isn’t just about people getting hurt. Those battery packs aren’t cheap either, seems odd to risk the investment, just to save a few bucks on the protection circuits. He got off kind of lucky, if he’d done some serious property damage, like to a customer’s vehicle, his insurance and the city might have wanted an investigation. Might have gotten through that, but not good for business, wouldn’t take my car there. Wouldn’t want safety corners cut, on any repair that I’m going to depend on at 80+ MPH…

  11. Rich has a gofundme to get his own garage. This happened at a friends/partners garage. Rich is one of the most entertaining DIY out there and he owned up to his mistake. It was a fail of the week. I think the most hurt people should be the Disney fans at the loss of the show car. It was a piece of history.

    That being said he is really doing a great job moving diy, open repairs forward.

  12. Once was working late and there was a loud ‘bang’ and the lights went out. Another tech and I wandered over to the breaker room to find the fuse/breaker panel glowing orange. We grabbed a couple fire extinguishers (dry chemical and CO2). Got the burning paint put out. Got the security guard involved and he called the local fire department and senior management. Fire department arrived, hooked up a blower to dissipate the smoke. Company electrician came on scene and had TPL reapply power to the building. We’d lost two fuses for the 480 line coming into the building. TPL installed new fuses on the pole outside and we watched as the lights came back on again. We had a little dancing arc running across ceramic insulators. Bad thing it also had a sooty flame about an inch high. Someone suggested putting out the fire. Good idea, right? They grabbed the dry chemical extinguisher and it worked as long as there were dry chemicals in it. That was dropped to the floor and the CO2 extinguisher picked up and used. They sprayed CO2 onto the little, dancing arc with a small flame. The longer they sprayed the bigger the flame got. The bigger the flame got the more they sprayed. Flame was about 12 inches high when it arced. First time I witnessed an electrical explosion. It blew molten metal and ceramic insulator all over the room. We were all wearing glasses. The company electrician got the worst of it. Frosted over the lens on his glasses, burnt off all of his eyebrows and hairs sticking out from under his ball cap. He got a free ambulance ride out of it. No permanent damage to anyone or anything. Called the local fire marshal the next day to find out what we did wrong. Yes, CO2 is good on electrical fires if the electricity is off. It was bad because the arc broke down the CO2 into carbon and oxygen, feeding the fire. We got lucky.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.