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Safety is a common concern as the automotive industry moves towards electric vehicles. In particular, focusing on the potential risks involved with li-ion battery technology is crucial as automakers move away from NiMH packs and towards li-ion storage.
Fire is a recurring problem with li-ion batteries, and we've all heard the horror stories of laptop batteries overheating and leading to fires. Naturally, this is a concern for vehicles as well.

Up until now, little was known about what caused these fires, but researchers over at Cambridge University think they have an answer, but it's not exactly one that we want to hear.

The researchers have identified the growth of metal fibers – called dendrites – within li-ion batteries. As they grow, these fibers can cause short circuits within the battery, in turn leading to overheating and fires.

What causes the dendrites to grow? When batteries are charged at a fast rate. This could certainly be a problem moving forward as nobody wants to hear about the need to trickle charge a battery to eliminate fires, but the researchers have another solution in the works. They suggest that determining why dendrites form will lead to new technologies that fix the problem, yet still allow fast-charging to be used. Though a fix could increase the cost of li-ion technology, it will also lead to a safer driving experience with less risk of an electric vehicle going up in flames. Hat tip to Jon!

[Source: BBC]


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  • 26 Comments
      • 3 Months Ago
      "Fire is a recurring problem with li-ion batteries"

      That TOTAL BS!!!

      It's a recurring scare story dramatized by ignorant media types.

      We've all seen pictures of ONE laptop with defective (internal contamination by metal particles) SONY batteries catch fire. All 10 million batteries were recalled in 2006.

      EV batteries don't even Lithium cobalt oxide chemistry. This story is placed so a bunch of uni researchers can get funding basically.
      • 3 Months Ago
      Actually, I think this is talking more about future technology rather than today's technology. Most batteries today use carbon (graphite) anodes because of precisely this dendrite problem. This research will allow usage of lithium metal anodes, which so far has safety problems, but should provide better density. I think Avestor/Batscap is the only one doing lithium metal anodes (in lithium polymer cells), and it hasn't really gone commercial.
        • 3 Months Ago
        I stand by my comment that this article is being unduly alarmist. No fires. Where are the fires? Carbon anodes are the scapegoat in some comments here.

        That might be an issue we'd need to look into under some circumstances. The Leaf uses a carbon anode I believe. But A123 does not, nor does Enerdel. Nor do startups Amprius, Envia Systems, Nexeon Limited, or Prieto Battery (source: http://earth2tech.com/2010/01/14/20-battery-startups-hitting-the-road-with-lithium-ion/ )

        Perhaps this will put some extra 'fire' under the researchers working on next generation batteries like Lithium Air or Zinc Air. That would be all to the good if so.
        "Lithium air batteries use a lithium anode"
        http://www.hybridcars.com/batteries/are-lithium-air-batteries-future-electric-vehicles-27957.html

        And Panasonic is not waiting. They're bringing out higher capacity batteries using a silicon anode: "Currently the material that is most commonly used in anodes is graphite and that reportedly allows 11% of annual rate of capacity rise compared with the 18% that the new material Si alloy will offer."

        http://thecoolgadgets.com/panasonic-next-generation-silicon-anode-li-ion-batteries-launching-in-2012/
        • 3 Months Ago
        @letstakeawalk
        See the direct quote from the researcher immediately below the commentary from the article that you quoted. The researcher is clearly talking about future tech.

        The dendrite problem certainly still applies to carbon anodes (it's the main reason why we even use them), but carbon anodes already go a long way to address safety problems. The only time we have seen battery explosions/fires are from manufacturing defects (either a bad batch or from a shoddy third party maker) or from unusual usage (the typical stuff in safety labels: water, direct sunlight, crushing the cell, overcharging etc). If you count all the battery incidents we have seen and compare them to the number of batteries out in the market (or even just the number of households/people using batteries), I think you will find batteries today are some of the safest forms of energy storage (esp if you compare it to incidents with any kind of flammable liquid like gasoline).

        This is unlike lithium metal anodes which have safety problems even in normal usage, which is why only Avestor/Batscap is attempting to make them (not that successfully either, since I think Avestor went under and Batscap had to buy them out).
        • 3 Months Ago
        "The researcher is clearly talking about future tech."

        The researcher is clearly talking about *the impact this problem has on* future tech. If they cannot solve the issue in current batteries - and I think they definitely will - it slows down moving to future projects.

        "According to Professor Grey: "Fire safety is a major problem that must be solved before we can get to the next generation of lithium-ion batteries and before we can safely use these batteries in a wider range of transportation applications. Now that we can monitor dendrite formation inside intact batteries, we can identify when they are formed and under what conditions.

        Our new method should allow researchers to identify which conditions lead to dendrite formation and to rapidly screen potential fixes to prevent the problem."

        The study itself, the research they did, was with current carbon anode li-ion batts. The results of this research will now be applied to the next generation of non-carbon anodes, so they can figure out how dendrites form in those specific batts.

        "These dead lithium fibres have been a significant impediment to the commercialisation of new generations of higher capacity batteries that use lithium metal as the anode instead of the carbons used today."

        The knowledge gained from this study of current batt anode chemistry will be applied to future anode chemistries, to avoid the problems that so far have prevented them from reaching commercial production.
        • 3 Months Ago
        Your assumption is incorrect. This study was done on Li-ion batt with carbon anodes - not some future tech.

        "But lithium batteries have one serious disadvantage: over several charge and discharge cycles, particularly if the batteries are charged quickly, minute fibres of lithium, known as dendrites, can form on the carbon anodes. These lithium fibres can cause short circuits, causing the battery to rapidly overheat and catch fire."

        http://www.physorg.com/news193217951.html
      • 3 Months Ago
      Laptop batteries are a totally different chemistry than electric vehicle batteries. Apples, meet oranges.

      And just how does one "fast charge" a laptop battery?
        • 3 Months Ago
        "Laptop batteries are a totally different chemistry than electric vehicle batteries."

        Except in the case of Teslas, eBoxes, and Mini-Es.... basically anything that's actually out there now. But in the broader (future) context, you are quite right.
      • 3 Months Ago
      "Fire is a recurring problem with li-ion batteries, and we've all heard the horror stories of laptop batteries overheating and leading to fires. Naturally, this is a concern for vehicles as well."

      A recurring problem. Really? Funny I haven't heard of any since 2006. "Naturally, this is a concern for vehicles as well." Really? This is the first mention of it I've heard outside of oil shill FUDster quackery.

      This article is the height of stupidity, making claims that a risk exists where none actually does. Just another oil industry shill trying to slow down electric vehicle dominance of the auto market. Every fiscal quarter is another 5.6 billion dollars for BP.

      Guess what, idiot, your toaster can catch fire. Should we worry about toasters as well?
        • 3 Months Ago
        "I agree, many of us who understand batteries realize this is a problem limited to a small percentage of older batteries - and not anything that should cause debilitating fear - the reality is that the manufacturers have a certain responsibility and liability (that will be enforced in a court of law).

        Based on a more complete understanding of the problem's cause, battery designers can work around the issue and make the appropriate improvements."

        Just in case anyone looked at my post and didn't realize I wasn't bashing anything...
        • 3 Months Ago
        I am pretty sure we knew about dendrites causing the shorts in Li-ion batteries a long time ago. Why is this news now?

        And newer electrode chemistries have mitigated this problem... hence the "fast charge" safe battery packs that Nissan has in the Leaf (manganese). And probably the Model S too.
        • 3 Months Ago
        It think that is a bit of an overreaction. I personally think there is a bit of mistranslation from the mainstream media grabbing this story (to which they have to add grabby headlines and dramatic laptop/cell phone battery explosion/fire images to get people to read the story). If you look at the actual paper, it is quite tame. It is talking about how this discovery can improve the safety of lithium metal anodes, which are not really in wide use today (see my comment below). The carbon-Li anodes in use today are really a compromise to keep batteries safe by sandwiching the lithium (my layman's description of the complex chemistry).

        I found the article I was talking about: http://www.eurekalert.org/pub_releases/2010-05/uoc-shi051410.php

        The key quote from the researcher is here:
        Writing in the journal Nature Materials, Professor Clare of the University of Cambridge says: "These dead lithium fibres have been a significant impediment to the commercialisation of new generations of higher capacity batteries that use lithium metal as the anode instead of the carbons used today."

        So really the researchers are talking about applications to future batteries, while the mainstream media turned it into more of an alarmist story on safety of past/somewhat current lithium batteries. Part of it is the journalists don't really understand the science, and part of it is a more alarmist story is guaranteed to sell more papers.
        • 3 Months Ago
        Thanks for linking to the post on Engadget that mentions the current HP battery recall being extended.

        I agree, it's a minor issue, and I'm glad researchers are able to make the needed improvements to continue to increase the safety of li-ion batteries.

        • 3 Months Ago
        I did a google search and found nothing newer than 2006: google 'li-ion battery fire'
        http://www.google.com/#hl=en&source=hp&q=li-ion+battery+fire&aq=f&aqi=g3g-m1&aql=&oq=&gs_rfai=&fp=b88d779eb9f1a91b

        Nice find on the story from India. Here's what the US had to say:

        "We haven't heard any tales of exploding batteries in quite some time, and we're sure that's in large part thanks to proactive battery recalls like the one HP has been running since about this time last year."
        http://www.engadget.com/2010/05/20/hp-expands-laptop-battery-recall-again/

        "The bad news is that your aging laptop could explode and wipe out your entire neighborhood at any moment. But, the good news is... free replacement battery!"

        So the real story is that laptop batteries are still having problems but the manufacturers are being very proactive and heading off any problems before they occur.

        It still doesn't in any implicate electric vehicle batteries. They are a different chemistry.

        Nice try. You almost made the oil shill of the week award. I suggest you try for the Darwin Award.
        • 3 Months Ago
        Poor David. Can't take a joke?

        Remuneration does not mean that money has changed hands. Perhaps they own stock in oil companies or have a family member in the oil industry. Perhaps they get their jollies by being disagreeable. Perhaps some are pathological and need to lie (perhaps even to themselves) at least once each hour in order to keep from going totally mental - much like the White Queen who admits "sometimes I've believed as many as six impossible things before breakfast."
        (source: http://blaine.org/sevenimpossiblethings/?page_id=2 )

        I don't know or care about the source of the oil shillery on display here almost daily. I just calls 'em like I sees 'em. After all, this is a site where we input our opinions.

        A friend of mine from ages ago used to say "opinions are like a$$holes, everybody has one and most of them stink." No bidets here in the US :^(
        • 3 Months Ago
        Hm.. are you sure? Cambridge university produced this report. Since when do universities, especially in Europe, get bought out by oil companies?

        It does seem fishy and uninformed though.
        • 3 Months Ago
        "A recurring problem. Really? Funny I haven't heard of any since 2006."

        I just have to laugh at those who are arrogant enough to think their ignorance disproves something's existence.

        HP has a battery recall going on *right now*.

        Hewlett Packard has extended the potentially faulty laptop battery recall program that was started last year on May 14. These faulty batteries are believed to have a potential of overheating and can burn or cause fire on the notebook."

        http://www.techtree.com/India/News/HP_Extends_Battery_Replacement_Program/551-111302-893.html

        Since dendrites grow larger as the battery ages, older batteries exhibit the destructive behavior more frequently. Brand new batteries don't, because it takes time for the dendrites to grow. I agree, many of us who understand batteries realize this is a problem limited to a small percentage of older batteries - and not anything that should cause debilitating fear - the reality is that the manufacturers have a certain responsibility and liability (that will be enforced in a court of law).

        Based on a more complete understanding of the problem's cause, battery designers can work around the issue and make the appropriate improvements.
        • 3 Months Ago
        Your repeated accusations that anyone who disagrees with you is a shill are tiresome and childish.
        Perhaps you do not know the meaning of the word, but it implies remuneration by a sponsoring organization.
        The notion that companies are paying people to blog here is fantastical.
        You are not a shill, but you certainly sound shrill.
        Please adopt a more measured and mature form of address.
      • 3 Months Ago
      Ms.Helen Ren ******************** Qinhuangdao Xinchi Photoelectricity Technology Co.,Ltd 275km South to No.102 National Road, Shenhe Industry Park, Funing County, Qinhuangdao,Hebei,China Tel: 0086-335-6309637 Fax: 0086-335-6309632 Msn: helenxcgd@msn.cn Skype: helenxcgd Yahoo ID: helenxcgd@yahoo.cn http://xcgd.en.alibaba.com/ http://www.xcgdbattery.com ********************** About Us Qinhuangdao Xinchi Photoelectricity Technology Co.,Ltd., was established in 2006, specializing in Research and Development, manufacture of high quality Li-ion battery. We offer wide ranges of batteries, LiFePO4 battery, LiMn2O4 battery, and also Li(NiCoMn)O2 battery, which are widely used in Electric Vehicle, Electric Bicycles, Power tools, Industrial miner's lamp, UPS, other industry and military fields, etc. With Advanced production equipment, professional manufacturing team, proficient production skills, we can produce more than 120000Ah per day. We have high-precision coating machine from Hirano Tecseed Co. Ltd (Japan), full-automatic Slitter Machine from Nishimura Mfg. Co., Ltd. (Japan), and full-automatic Filling Machine from Hibar systems limited (Canada), and many other imported production equipment or domestic high-end auxiliary equipment to ensure our products high quality and consistency. XINCHI products will not only be tested during every step of the whole production process, but also exfactory inspection will be taken, for example over discharge, anti-aging, short circuit, drop, extrusion, prickling, and other safety inspection. Advanced testing equipment and professional quality inspection system are an efficient guarantee to the quality of our products. Therefore, every index of XINCHI products is better than national standard. At the moment, all the batteries of our company has got ISO,CE ,UN38.3,MSDS and ROHS certificates.
      • 3 Months Ago
      "Up until now, little was known about what caused these fires".

      That is s stupid statement. Thousands of scientists have worked out how to design safe battery chemistries like Li Manganese that Nissan uses - and they want us to believe nobody knows what causes fire ?
      • 3 Months Ago
      "Up until now, little was known about what caused these fires"

      So, a fast charged battery can get hot? A hot battery can get hot enough to catch on fire? Really? I didn't know.
      • 3 Months Ago
      It's all in the battery management and chemistry. Design it properly and it will last a very long time without fault.

      This is why cheap cellphones explode, and early lithium batteries had problems with blowing up also. Bad battery management.

      You don't really hear about those things occurring anymore. I haven't seen a story about laptops blowing up since '08.

      As for fast charging, yes.. i think a 3-10 minute charge time is unrealistic but i'm not a battery or electric car engineer. Just a computer technician.
      • 3 Months Ago
      It take a small inboard gasoline electric generator to help manage the battery. Batteries are not meant to fast discharge or fast recharge. With a small electric generator the entire package work better. That's not weird science. The volt is such a car but both the battery and electric generator are way too big and costly.
      • 3 Months Ago
      BULLSHIT! I called it first.

      Lithium Iron Phosphate, the predicted dominating chemistry for EVs for the next 5 years, withstands 300ºC celsius, metal puntures, strong (100C) shortcircuits without fires.
      Lithum Manganese, Lithium Cobalt, and other chemistries used in cell phones, laptops, etc, withstand far less temperatures (90ºC), and metal punctures are fire starters.

      These causes were known BEFORE public flames were filmed... as always, cost pressure led makers to try and see if they could do with less than prestine BMS. Dendrine forming is always an issue with chemical batteries (it happens in lead-acid also).

      It's not apple meet oranges, it's "money in my pocket, must write 200words post, let's trash EVs".
      Hat tip to Jon???!!? in which BP-run bar did he heard about these """"issues""""?
        • 3 Months Ago
        LiFePO4 is indeed one of the safest right now. But the Li-Manganese variants are also pretty safe.

        It is only the Li-Colbalt batteries that have been involved in the 'thermal runaway' (AKA laptop battery explosion/fire) events.
      • 3 Months Ago
      Tesla's management system already took care of this problem - any cell in the pack can blow, it won't cascade to other cells, and the car will perform flawlessly. They also manage the charging very well - their batteries never get hot enough or are charged hard enough - their "quick charge" is to 80% in 45 minutes for the Roadster (as I recall, anyway...I'll have to go back to Tesla's site to verify).

      This doesn't concern me or disuade me from buying an Li-ion based vehicle. The public needs to know that it's possible, but it's not the problem that it's played out to be in the media, as others have already commented above. Besides, it's pretty much only Tesla that is using off-the-shelf Li-ion cells. Everyone else is using different designs, geometries and chemistries that either minimize or completely eliminate these problems.
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