One minor chink in the armor of the Tesla Model S is that a small number have caught fire, once their battery packs were penetrated. Nissan Leaf drivers, however, might just be able to weather such an event without an ensuing CarBQ.

Our evidence for such a claim? A video that has surfaced of cells from a Leaf pack undergoing a battery of torture tests (pun somewhat-ashamedly intended). Shared by folks at the Hybrid Auto Center in Las Vegas – who offer for sale, among other things, used Leaf lithium battery modules – the footage shows salvaged cells being brutally assaulted with a screwdriver, and later, a propane torch. Granted, these tests are not the same thing as flinging a piece of metal into a working pack at 70 miles per hour, but they do claim to show that a puncture does not always equal a fire. Oh, and don't try this at home.

When pierced through by the flat head tool, there is no explosion or eruption of flame. Instead, a rather modest wisp of smoke shyly emerges as the electrolyte next to the shorted area of the fully-charged foil pouch reacts with the influx of oxygen. Again and again, the blade descends, until the cell is riddled with holes. No fire.

Amazingly, when connected with a voltmeter afterward there are still plenty of signs of life, and when it is charged and discharged (off-camera), it reportedly suffers only a slight loss of charge capacity. The video goes on to show another cell attacked with open flame with similar results.

While the demonstration is, perhaps, somewhat crude, the message it sends is loud and clear: lithium batteries can be safe and rather robust, despite some freak accidents. Scroll below to watch the short presentation for yourself.



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  • 40 Comments
      HVH20
      • 9 Months Ago
      SAE J2464 - Read it. If your going to do a nail penetration test, do it right. Results can be skewed by nail size, speed, tip angle, cell SOC, cell constraints, having spark sources present, etc... Simulated fuel fire, overcharge, over discharge, over temperature, they are all standard abuse tests in industry.
        2 wheeled menace
        • 9 Months Ago
        @HVH20
        Well, you can buy a nissan leaf cell pretty cheap as salvage and do the standard tests yourself, if you wish. But real life crash conditions are never controlled like this. The results are still good. Most cells do not tolerate puncture of that sort so well.
          2 wheeled menace
          • 9 Months Ago
          @2 wheeled menace
          Both formulations are safer than average. There could be a pack design issue that causes the Model S to go up in flames under a severe collision. But really, one could expect a gasoline tank to do the same thing. Any spark will set it ablaze just the same. Thankfully, the Model S pack is designed in such a way that any discharge from the battery will be redirected from the passenger compartment. Many gasoline vehicles have the fuel pump located directly below the rear passenger seat. It's very possible for the interior to go up in flames because of this, and the occupants inside.. a lot of people die this way.
          JakeY
          • 9 Months Ago
          @2 wheeled menace
          "The results are still good. Most cells do not tolerate puncture of that sort so well." Looking at my link, the NCA cells that Tesla uses actually tolerates a cell puncture quite well (page 14), so obviously it does not tell the full story: http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/es142_sriramulu_2013_p.pdf
      2 wheeled menace
      • 9 Months Ago
      That's excellent results. Tiny amount of smoke from that series of punctures. Pretty much exactly how you'd want ta battery to perform in a major collision. Possibly safer than a fuel tank full of gasoline being punctured as well. ( any little spark will set off fuel vapors and thus, burn off the entire tank! ) My RC Lipo cells on the other hand, in any kind of puncture, will turn into a death metal pyrotechnics show for a span of a few minutes. Just youtube search for 'RC Lipo fire'. This test is not exhaustive, but good anyway.
      • 9 Months Ago
      I'm glad to see this genius wasn't hurt, while not wearing much, if any, safety gear. If he had been, all we'd hear would be the haters talking about the Li-Ion battery "specialist" injured/killed by a Leaf battery. Of course, get hurt performing the same degree of destructive testing on a gasoline-powered system, and it probably wouldn't make the news.
      StaceyS
      • 9 Months Ago
      Not really a realistic comparison of durability when one mutilates individual cells. One of the problems is that when the cells are in an operational pack, the voltages and amperages are larger and more potentially destructive to individually damaged cells. Put a screw driver through a single cell while its connected to the rest of the module and you'll probably see a different result...
        2 wheeled menace
        • 9 Months Ago
        @StaceyS
        Nope.. at worst, the cell(s) that is/are weakened by being stabbed would drop voltage and amperage. Under load, this would cause the BMS to cut off. Instead of having one cell putting out a little smoke, you'd have a bunch of cells putting out a little smoke, each. If you watched all of the video, you see that he tortured it while charging and/or discharging. Why do you think that we've never heard of a Nissan Leaf fire yet?
          StaceyS
          • 9 Months Ago
          @2 wheeled menace
          Did you down rate my comment and up rate your own? My comment wasn't specific to the Leaf battery, its actually a real point of concern for any lithium based battery pack. The point I was trying to make is that when you add multiple cells together in a module, the power increases within that array (voltages and amperages). Damage to specific cells in an array have the *potential* (not the certainty) for higher danger simply because there is more power in the array. If damage were to short a module containing multiple cells, that short could be potentially worse than just shorting a single cell. My point was simply that doing destructive demonstrations on single cells isn't really comparable to demonstrations of cells in a module or pack. Those BMS you mentioned and other safety systems are integrated into modules and packs for this very reason.
          chanonissan
          • 9 Months Ago
          @2 wheeled menace
          sorry for the double post, there have been accident but nissan car is build with a next safety feature that when the car detect an accident, the system disconnect the load. So it would be like this battery which is tested no load, hope that help you.
          JakeY
          • 9 Months Ago
          @2 wheeled menace
          "Why do you think that we've never heard of a Nissan Leaf fire yet?" I don't think you necessarily can make that conclusion. It may simply be because the Leaf haven't been in an accident where there was a pack puncture yet (I haven't heard of any incidents, please correct if you are aware). In contrast, I know of 5 separate incidents where the Tesla pack was punctured (two of those had fire). Now you CAN comment on the prevalence of pack punctures, but that's unrelated to battery cell safety.
      BipDBo
      • 9 Months Ago
      This is one of the reasons why I think that the hysteria over Tesla and it's stock is bound to expire and come back down to reason. I don't think that the Tesla has any special secrets that GM and Nissan don't already know. In fact, GM and Nissan likely have better battery technology. GM, Toyota and Ford certainly have a lot more work into plug-in hybrid development, which is probably more likely the path to widescale EV adoption. When other companies start building cars in the same market (performance luxury) as Tesla, then the hysteria will calm down.
        chanonissan
        • 9 Months Ago
        @BipDBo
        you really think that is only gm, toyota, and ford have more development,because they have PHEV on the market? Well I must tell you nissan have being advance in development in PHEV. Not only toyota and ford have a full hybrid system as far back in 2004, nissan did produce a full hybrid only for japan market in 2000 call tino hybrid, not because nissan did not sell a hybrid in USA before the altima or a EV before 2010 in USA, that does not mean they did not build them, or they are far in development. http://www.nissan-global.com/GCC/Japan/NEWS/20000323_0e.html this even show that in 2004 while nissan did not sell or produce them, just like toyota keep on updating their hybrid system, nissan was doing the same regardless. http://wardsauto.com/news-amp-analysis/nissan-tests-smart-hybrid-vehicle Forward to 2014 the renault/ nissan alliance have just patent a motor with a three speed transmission intergrated in it for PHEV for 2016, there is also a different PHEV that will come to market 2014. First there will be a renaut PHEV follow by nissan PHEV, ford nor toyota have PHEV in europe. http://www.whatcar.com/car-news/nissan-qashqai-plug-in-hybrid-confirmed/1211420 http://wardsauto.com/vehicles-amp-technology/new-electric-motor-drives-renault-phev-project http://green.autoblog.com/2013/12/09/renault-readying-141-mpg-phev-for-geneva-expects-250-mile-evs-b/
          chanonissan
          • 9 Months Ago
          @chanonissan
          One might ask why nissan license toyota hybrid for the usa market, but one must remember nissan had financial problem ealier, getting back to profit was their main objective and renault was now involve in some decision making.
        purrpullberra
        • 9 Months Ago
        @BipDBo
        Why isn't Toyota buying from better suppliers, and Mercedes? Because you're wrong.
      jack smith
      • 9 Months Ago
      The simple fact of the matter is that Tesla made an active decision to go with an standard lithium battery versus the "safe chemistry" lithium batteries that are available. They received quite a bit of flak about this long before the first Tesla fire had ever happened, and they made this decision because "unsafe chemistry" batteries generally have a higher capacity over their safer cousins. As a disclaimer, no lithium battery is completely safe. However, many lithium varieties are inherently safer, such as lithium manganese (IMR), IMR hybrid, lithium polymer, etc. and et. al. As an example, this video shows the difference in behavior between a standard lithium cobalt and the safer chemistry lithium polymer from NEOCELL. Just look up: "Battery Puncture Test: GTS NEOCELL® vs Standard Li-Ion" Tesla chose greater electric range, capacity, and discharge rates over a safer battery. This is fact, research it for yourself.
        chanonissan
        • 9 Months Ago
        @jack smith
        nissan battery is not lithium ploymer, it is Li-Ion with a more robust chemistry LMO. And there is a variety of Li-Ion which is robust. http://en.wikipedia.org/wiki/Lithium-ion_battery
          jack smith
          • 9 Months Ago
          @chanonissan
          @Chan Care to point out in quotes where I stated that the Nissan had a polymer battery?
          2 wheeled menace
          • 9 Months Ago
          @chanonissan
          It is technically lithium polymer. Every pouch cell is lithium polymer. ( lipo is a physical descriptor, NOT a chemical descriptor ) It is also a lithium ion battery. :D Wikipedia's battery article has been broken for eons.
          chanonissan
          • 9 Months Ago
          @chanonissan
          you care to point out that I said you did, but your post claim difference in behaviour of standard li ion to safer li polymer, and I said the nissan battery is a li ion. @2 wheeled li ion and polymer have similarities that they are better than NiHm, but they are two different kind of batteries because of the material used as the seperator. http://www.allaboutsymbian.com/features/item/15775_How_do_Lithium_batteries_work.php
          jack smith
          • 9 Months Ago
          @chanonissan
          @Chan "I said the nissan battery is a li ion." Except the Nissan battery is a Lithium Manganese Oxide, specifically spinel. This type of battery is generally known as IMR. This type of battery is also known for it's safe charging and discharging, and as such, does not need a protection circuit to prevent over charge or discharge. All batteries that use Lithium as a cathode are referred to as "Li-ion" because they use Lithium as a cathode and ions move from negative to positive electrodes. Polymer batteries are no different in this, though you seem to think they are. The standard set of Li-ion batteries uses cobalt, and requires protection circuitry. If overcharging or discharge ever happens, the battery will perform exactly as all those Dell batteries did in the 90s. Tesla chose to go with a Lithium Nickel Cobalt battery (notice the cobalt?), while the Chevy Volt and Nissan leaf went with IMR. The Tesla battery will have greater capacity (per pound) over the IMR, and a longer calendar life. The Volt and Leaf's IMR battery can discharge greater amperage (in C) per pound than the Tesla battery (since it won't explode on over-discharge), does not require protection circuitry, and is generally a much safer chemistry. Take a chemistry class and learn something.
        2 wheeled menace
        • 9 Months Ago
        @jack smith
        Actually, Tesla's Panasonic cells do have more safety features than the average cell. They're not bad at all. But the catastrophic impacts that Tesla's cars have been put through ( which caused a battery fire ) have been just as bad as any internal combustion engined car collision. There's a point where, you can have the safest cell in the world, but a bunch of electrical things shorting together under heavy impact is going to get you fire no matter what.
      JakeY
      • 9 Months Ago
      Actually any smoke coming out of the battery means failure already as that means heat was generated and it could still lead to fire. And the thing about nail tests is that they can easily be gamed. One variable is SOC. Even for "dangerous" cells, it's possible not to get fire simply by not fully charging the cells. His test wasn't even a true nail test as he used a flat-head screwdriver (which would not necessarily ensure full puncture through the all the layers of the cells). It seems in general, conventional nail tests (with simple pass fail) is more of a gimmick than something that tells you the real safety of the cell. You really need thermal imaging at the least to see if the nail heated up. http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/es142_sriramulu_2013_p.pdf
        2 wheeled menace
        • 9 Months Ago
        @JakeY
        You must have not watched the part of the video where he has a butane torch to the cell. Whether you put a nail or a screwdriver through the cell, you are still shorting one part of the cell to another, fyi. You are also puncturing the pouch, which is usually a fatal blow for most cells, which causes fire or at least a *massive* amount of smoke. He did it ~3 times.. no fire.. little smoke..
          DarylMc
          • 9 Months Ago
          @2 wheeled menace
          To be honest I have no time for the trolls who attack Tesla but I also have little time for the people who seek to advance their portfolio or new found religion as it may be. Tesla has done a fine job of making an EV and these people can only hurt that.
          DarylMc
          • 9 Months Ago
          @2 wheeled menace
          2 wheeled menace There is something unusual about the comments on this story and I'm putting it down to the words Tesla and fire in the first line. It has really taken away from the fact it is just a video about a fellow stabbing and torching a cell. I was also impressed that it did not spontaneously combust and probably more interesting to me was able to function somewhat.
          JakeY
          • 9 Months Ago
          @2 wheeled menace
          I'm just saying, in a proper nail test, any smoke coming out of the battery means failure (see my link). And what I mean by the screwdriver vs nail comment is that with the nail, you are sure you punctured through all the layers of the cell (see the link I gave, all the tests have a clean puncture through all the layers of the cells). With a flat head screwdriver, you may not have punctured through the separator (you might have simply just deformed it), esp. given he did it on the ground (rather than having the bottom empty so that the screwdriver goes all the way through). See here for the AESC cell, there's at least 9 layers (anode, separator, cathode, separator, etc), you can't tell from the video how many layers the screwdriver went through and obviously there's a significant difference in danger depending on how many layers you go through: http://www.eco-aesc-lb.com/en/product/img/img_index02.jpg As for the butane torch, I saw it, I have no comment on that as I have never see batteries tested that way, so I don't know how significant a test it is in simulating battery safety relative to other batteries.
          chanonissan
          • 9 Months Ago
          @2 wheeled menace
          he knows little about shortage, how they spark, burn wire ETC, and how many fire they cause.
          2 wheeled menace
          • 9 Months Ago
          @2 wheeled menace
          Smoke coming out of a battery meaning failure is too high of a bar to cross. That is like expecting gasoline to not come out of a gas tank after being punctured. Smoke coming out of all cells simultaneously is still such a small amount that it is not going to cause harm. Like i said to another person, used nissan leaf cells are cheap to buy on eBay today. You can purchase some and test them in the manner you see most proper. Make sure you tell Domenick Yoney about it, as he is more likely to post up your results than other bloggers. :)
      EVH
      • 9 Months Ago
      This video is horrible. Like other reviewer said... The battery isn't even in use... Try shooting the battery while it's in use and hot at wall at 100 mph. I'm sure the Tesla battery would easily pass this test also...
      purrpullberra
      • 9 Months Ago
      Interesting. I wonder about piercing several of these packed tightly together, would that cause a fire? Seems more real world than this almost pointless 'experiment'. Whatever.
        brotherkenny4
        • 9 Months Ago
        @purrpullberra
        I though there would be dead people from the exploding batteries by now. In the real world batteries are safer than gasoline, and while it's still important to make batteries safe and safer, what we see in the "NEWS" is not in the real world. No picture of a burning battery will be placed in the NEWS, because it is still all the plastics and tires that produce the impressive flames and smoke. So while the batteries may flame and start bigger fires, they themselves are not as bad as everyone says. There just isn't that much energy and fuel in a battery. Ten times less energy than a gas tank and only a few liters of organic solvent. You also have to realize that anyone doing battery safety work will set up and film battery failures in modes that are not realistic so they can get spectacularly scary results. It's what gets them funded to do more testing (fear), and keeps them employed. If they solve the problem, they are out of a job, so they are always needed as the scary test they do prove.
      Mike
      • 9 Months Ago
      So a Lithium Ion battery not in use can be punctured and torched. That's not much of a test to compare why the Tesla's caught fire and Boeing 787 caught fire. Ever use an HTC phone with GPS running, it's so hot it hurts at times. THAT is what is causing fires. When uber hot batteries touch certain materials, things catch fire.
        2 wheeled menace
        • 9 Months Ago
        @Mike
        The Boeing 787's cells were lithium cobalt ( afaik ) GS Yuasa cells, FYI. One of the formulations with the worst safety, generally. Particularly bad design for an air-going vehicle !!!
        chanonissan
        • 9 Months Ago
        @Mike
        telsa battery did not caught fire by being in use, they caught fire when they were puncture via accidents or something hitting the battery, this short film is showing that the leaf battery when hit (short out) well probably not caught fire.
          JakeY
          • 9 Months Ago
          @chanonissan
          What he means is the Tesla batteries were punctured while there was a load over them (as the car was still being driven). These cells were punctured while it the battery was open.
          chanonissan
          • 9 Months Ago
          @chanonissan
          did you know that one caught fire when there no load on it? http://www.autoweek.com/article/20140214/CARNEWS/140219877
          2 wheeled menace
          • 9 Months Ago
          @chanonissan
          Chano, that battery did not originate in the battery.
      RC
      • 9 Months Ago
      While not a scientific study, the video makes a point, some concerns are just overblown.
      brotherkenny4
      • 9 Months Ago
      The more recent cell chemistries are much safer than LiCoO3 cathode cells, and far safer than gasoline. We need to not be so passive in accepting negative messages from the media outlets, who are just trying for viewers or readers so they can sell advertising. Their advertisers are also sometimes more interested in maintaining the markets as they are, since they already make the money. Change is risk to their investments, which is all they care about. A thousand and one car things to do before you die? How about really fun things that don't involve behaving as frivolous brainwashed consumer?
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