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Good ideas with bad execution, or good execution of what should be bad ideas - an analysis of inferior, off-beat or malfunctioning products, and how other people's failures can help us design better stuff.

What’s Wrong With Lithium-Ion Batteries?

21el4kutowl.-aa195-.jpg The announcement last month that 46 million Nokia-branded lithium-ion (Li-ion) batteries made by Matsushita Battery Industrial could potentially short circuit and overheat was just the latest in a spate of product advisories and recalls of the technology over the past two years. But it’s not as if Li-ion batteries are at the early point in their life cycle when you would expect these sorts of problems to crop up. Sony invented the technology back in 1990. So why is it failing now? The theories behind the technology’s recent spotty performance are complex and varied, which makes fixing the problem a perplexing engineering challenge. A Constantly Evolving Technology “You can’t really say that for the first ten years the battery makers got it right and now they’re screwing it up,” says Jim Miller, Manager of Argonne National Lab’s Electrochemical Technology Program. Funded by the U.S. Department of Energy, his group’s research is directed at developing new materials for Li-ion batteries and addressing some of the major issues in scaling up the technology. Miller points out that Li-ion battery technology is not just a single design or composition, but rather it’s an entire family of chemistries that is constantly evolving. “When Sony invented it in 1990, it was lithium cobalt oxide. But cobalt is expensive and so engineers started replacing it with nickel, which costs less. And then as time went on engineers found that they could substitute cheaper nickel manganese alloys for the nickel.” Cost reduction isn’t the only driving force behind the evolutionary march of Li-ion batteries. The desire to extend battery life, achieve higher energy densities and faster charging times, and improve reliability has led to a constant tinkering of the technology. Energy densities are double what they were five years ago, for example, and new surface coatings are being applied to make the batteries more stable and reduce their reactivity rates. Ever-Increasing Demands, More Trade-offs The trade-offs inherent in these often mutually exclusive goals make for a diabolical design challenge: You can make a Li-ion battery that has high performance, for example, but the trade-off is a shorter life. And as every design engineer knows, making the right trade-offs and getting everything right takes time, experience, and a bit of finesse. “A problem doesn’t necessarily pop up during the first generation of cells,” says Miller. “Things may look fine in the lab and then when you go to production you find that the technology behaves in a slightly different way, which means things can and do go wrong.” Something certainly went wrong at Sony last year, resulting in the recall of millions of its Li-ion laptop batteries. As for what exactly led to the short-circuiting problem that posed a risk of fire and in one case caused a Dell notebook to burst into flames, Sony Spokesperson Rick Clancy says that there were different conclusions at different levels. “When you produce lithium ion batteries, the objective is to either have zero metal contaminants or at least as few of them as possible and surround them by a protective shell or layer so that they cannot penetrate the separator,” explains Clancy. The separator in a Li-ion battery keeps the anodes and cathodes from touching each other and causing a short circuit. Clancy says that Sony engineers discovered that there was a greater frequency of these metal particles escaping from one part of the cell and entering the other part. They’ve addressed the issue at a product level by designing in a stronger lining, he notes. But there were other findings at a systems level, specifically relating to variances in configurations and specifications for battery packs from the PC makers, says Clancy. “They are doing the most they can to optimize their products and make them as competitive as possible, which is putting more demands on the power supply as it relates to the battery.” He adds that some manufacturers’ charging systems are more aggressive than others, which could have had the effect of either vibrating or shaking the batteries more aggressively, a phenomenon that may have played a role in the short circuiting problem. He says engineering teams from Sony and the PC manufacturers are working closely together to better understand and more effectively manage these systems issues. A representative of Matsushita Battery Industrial (MBI), the company that manufactured the 46 million Li-ion batteries named in the recent Nokia product advisory told Electronics Weekly in a phone interview that the company is still investigating the cause of 100 incidences of batteries overheating. But he too pointed to the ever-increasing demands on Li-ion batteries. “Generally speaking the batteries are getting smaller and smaller, and at the same time they are being required to deliver more power and capacity. The engineering challenge for us is to maintain the same degree of reliability throughout,” he says. Although he ruled out any possibility of process-related problems, the manufacturing landscape has widened since the Japanese developed the technology in the 1990s. The cells for the batteries implicated in the Nokia advisory, for example, were manufactured by MBI in Japan and shipped to a factory in China where they were assembled into battery packs. The batteries involved in the Sony recall carried labels marked “Made in Japan,” “Made in China,” or “Battery Cell Made in Japan Assembled in China.” Sony produces Li-ion cells in plants in Japan and China, assembles some battery packs at a Sony plant in China, and in some cases sells Li-ion cells to third party makers of battery packs. Sony says that off-shoring was not a factor in last year’s recall. But Don Sadoway, a professor of Materials Chemistry at MIT who is an expert in advanced battery technologies, worries about off-shoring of a chemistry he asserts “needs to be treated with respect.” “I have 100% confidence in the Japanese battery manufacturers,” he says. “And my guess is that they never had the problems they’re seeing now when the same batteries were manufactured from start to finish in Japan.” He notes that one of the challenges with Li-ion batteries in particular is that it is very difficult to verify that the manufacturing and assembly is being performed according to specifications. That’s because once it’s assembled into a battery pack, the device cannot be inspected from the outside nor can it be easily tested. Sadoway points to the separator material between the electrodes as an example. Acting like a kind of fuse, it is designed to soften and collapse at a specific temperature, causing the battery to essentially go into an open circuit condition and die. In fact, he wonders why that didn’t happen in the case of the Dell laptop that burst into flames last year. “You could think you are specifying a porous polypropylene material for the separator, but once the thing is packaged up you would have no way of knowing what you actually got. Even under the best of circumstances, you can get screwed by your own job shop. What if the workers took a short cut and substituted the original material with cardboard?” In at least one case, it’s suspected that battery manufacturers were supplied with counterfeit raw materials. Argonne’s Miller agrees that is very difficult and expensive to test and verify Li-ion batteries, adding to the cost that manufacturers presumably hoped to reduce by off-shoring assembly in the first place. But he says that quality assurance can be engineered into the battery design, and that he believes suppliers of cell phones and laptops are tightening up the process. “They are getting more precise in the materials they are using and in their cell designs,” he says. Still, Sadowy believes that much more rigorous oversight and stringent quality assurance is required, especially as Li-ion batteries scale up. The technology is expected to hit the road in the next few years in electric vehicles under development such as the GM Volt. “If your MP3 player fries, it’s not a big deal, you don’t get to listen to your favourite tunes,” says Sadoway. “I have real worries when we try to build a large format Li-ion battery with 100X the capacity and put it out there on the highway.”

Tags: battery makers, cobalt oxide, evolving technology, Short Circuit, spate

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31 Comments

  1. Anonymous
    November 12, 2008 12:57

    hi this was a good website

  2. Anonymous
    October 02, 2008 20:13

    you suck

  3. July 16, 2008 04:19

    well, just like the Toshiba pa3291u-1brs, a lithium-ion laptop battery, when i charged it over 10 hours, it get a overheat effect and decrease it’s life. every synthetic has it’s weak point, all we can do is abide by the derection of the product, try to extend it’s life as best as it can. and keep safe at the same time. most electronic products is safe when you use them correctly. afer all, no company want to go bankrupt because of injure a customer.

  4. July 14, 2008 02:34

    lithium ion rechargeable battery have a longer life,an no memory effect,many people chose it.there are same cheap lithium battery on http://www.digital-camera-batteries.net

  5. May 27, 2008 05:21

    Sony produces Li-ion cells in plants in Japan and China, assembles some battery packs at a Sony plant in China, and in some cases sells Li-ion cells to third party makers of battery packs. off-shoring was not a factor in last year’s recall.
    more info cheap-laptop-batteries.com

  6. March 15, 2008 06:02

    Lithium batteries deteriorate from the time of manufacture (a chemical process). With a life span of about 2 to 3 years. i read it from http://www.lithium-batteries.net

  7. Henry Mohan
    January 18, 2008 03:26

    Any idea if the batteries that exploded ONLY came from those assembled from China???
    The batteries involved in the Sony recall carried labels marked “Made in Japan,” “Made in China,” or “Battery Cell Made in Japan Assembled in China.”
    But Don Sadoway, a professor of Materials Chemistry at MIT – “I have 100% confidence in the Japanese battery manufacturers,” he says. “And my guess is that they never had the problems they’re seeing now when the same batteries were manufactured from start to finish in Japan.”
    H Mohan

  8. loggerdon
    October 23, 2007 16:12

    We use a proprietary Lithium Ion battery for a product I sell. We have had problems with the battery swelling. They are supposed to provide 20 hours of continuous use.
    Any ideas what causes the sweeling? They are manufactured in China.

  9. Manu T
    September 09, 2007 12:51

    This line:
    “And my guess is that they never had the problems they’re seeing now when the same batteries were manufactured from start to finish in Japan.”
    And this line:
    “In at least one case, it’s suspected that battery manufacturers were supplied with counterfeit raw materials.”
    Say it all. We definitly should be producing locally at the western technology-iteread world again instead of using third world countries. Or worse countries with prehistoric environments. Especially it’s so ridiculous that major industry-players produce their stuff in china nowadays but expect the western world to buy it.
    I’d say stop that! If you want US to buy your techno-crap then let US build it. Period!

  10. Kadri Kodanik
    September 08, 2007 15:43

    i have a problem, my omputer Apple MacBook doesen’t charge it’s battery. I have read that the lithiumion batterys voltage may not be too low. So the battery is totally useless. But is there anything how i can fix it by myself or i have to buy the new battery.
    Please help me, i’m really in trouble.

  11. September 07, 2007 12:28

    Linkpost | 9.7.2007

    • Microsoft Security Bulletin Advance Notification for September 2007 — Five updates coming next week, only one is rated critical. • Seattle man arrested in file-sharing identity theft • Justice Department opposes ‘net neutrality’ • Apple Hi-Fi, RIP: …

  12. Paul Murray
    September 07, 2007 10:09

    My laptop battery was rested for five months and has regained nearly all its capacity.
    After about two years of use the battery in my Dell laptop was down from about three hours use to less than one. I bought a cheap replacement but this was dying after only five months use and quickly dropped to an hours use. The supplier agreed to replace it without argument so I swapped the original battery in (luckily I hadn’t got around to disposing of it) while I shipped the faulty unit back. To my amazement I am getting about two and a half hours use from it!
    I haven’t bothered to use the replacement battery yet.

  13. September 07, 2007 09:02

    These days batteries are exploding just because of pressure on manufacturers on price drop and so they are not giving much importance on quality control. Just talk example of old computer perpherals, they look solid and still work, while new ones start making problem since day one of use. If a lithium ion battery is well asembled at plant and well built, it will never explode. Other causes of bateries exploding is use of chinese made chargers which may exceed the charging current rating and thus increasing the battery temp. while charging.
    ______________________________________
    (c) http://www.thenetguruz.com/

  14. Robert
    September 07, 2007 04:57

    For all practical purposes, there never was a memory effect in NiCd cells. What most people mistook for “memory” degradation was in fact stupid chargers that would overcharge the cell, sometimes to the point that it would vent gas, altering the battery’s chemistry to the point it couldn’t hold as much of a charge. See: http://www.repairfaq.org/ELE/F_NiCd_Memory.html
    Lithium batteries require a very careful charge cycle – any mass-produced charge controller will prevent the cell from being overcharged, lest this happen:
    http://video.google.com/videoplay?docid=3690260570423705609

  15. Anonymous
    September 07, 2007 04:09

    Lithium Ion batteries deteriorate from the time of manufacture (a chemical process). With a life span of about 2 to 3 years. I read this in an article about A Year ago.

  16. Alfred Steele
    September 07, 2007 00:00

    Geoff — when using Li-Ion batteries in R/C airplane we have a device called an Electronic Speed Controller (ESC). Most ESC’s also contain a Battery Elimiter Circuit (BEC). When flying using a single battery for both the motor and the R/C receiver/servos when the total voltage gets down to 3.0 volts per cell the ESC cuts power to the motor but continues to supply power to the receiver/servos via the BEC. This give you enough battery power to land safely and not over discharge your batteries.

  17. Anonymous
    September 06, 2007 22:11

    Geoff — skip Li-ion or LiPo and go direct to A123. You’ll be a lot happier. See http://www.a123racing.com or search for A123 in the R/C forums.

  18. Anonymous
    September 06, 2007 22:09

    I’ve been using A123 LiFe cells harvested from DeWalt’s new 36v batteries for my R/C cars. Although they don’t have the same density (50% larger volume for the same mA/h), they don’t catch on fire from over/under charging.
    They’re incredible @ 70A typ. discharge rate (peak to 120A) and you can charge them @ 10A per cell for well over 1000 cycles; They don’t get hot like LiPo, NiCd or NiMh and they are happy to provide 100% depth of discharge every time, even when back-to-back charging.
    They have a large automotive cell (for the Volt, which I’ve never seen) and a smaller format (longer “C-sized” 3.6v 2300 mA/h cell) used in the DeWalt packs.
    This new nano technology in the A123 cells DO NOT belong in the same conversation as the current Li-Ion or LiPo.
    See their website at http://www.a123systems.com
    (no, I don’t work for them, just a very happy end user)

  19. Geoff
    September 06, 2007 21:57

    Alfred:
    So how do you prevent overdischarge of your Li-ion batteries in your RC application? Any good recommendations on where to shop for chargers and batteries? (I’m looking at replacing my RC nicad pack with Li-ion.)

  20. September 06, 2007 17:14

    It is not just the demands on Li-Ion batteries themselves that are higher (smaller size, less weight, capacity, quicker re-charging, less “memory effect” etc).
    But also the uses of devices which have batteries are becoming more extreme. So more and more they are in products which are in environments with higher shock impact, humidity, dust, vibrations, exposure to sunlight, more extreme temperatures, misuse by customers, etcetc.

  21. Alfred Steele
    September 06, 2007 17:06

    I use Li-ion batteries to run my motors in my R/C airplanes. I have a special charger that does a balance charge. Each cell in the battery is charged individually so it won’t be over charged. It also keeps all the cells at the same voltage level so that during discharge no cell will drop below 3 volts. Also, places that cell Li-ion batteries tell you to charge them in a fire proof box or outside. Some people charge them in their fireplace. Never leave a Li-ion battery charging unattended. It looks like the R/C industry is much more safety conscious then the Laptop industry.

  22. watt
    September 06, 2007 15:18

    @Adrian Davies: Nope, no memory effect. However Li-ion batteries are extremely sensitive to over charging and over discharging. You laptop should have circuitry in it that doesn’t allow this to happen, but if it messes up it will drastically reduce your battery life.
    @Graham: NiFe cells are probably the most robust batteries money can buy, but their energy density is about an order of magnitude less than Li-ion cells. I, personally, wouldn’t mind carrying around a 10 lbs. laptop if the batteries were completely safe and would never diminish in capacity, but most people would rather a 2 lbs. laptop even if it means they’ll have to replace the batteries once a year and might burst into flames or so most marketting departments believe.

  23. Gene
    September 06, 2007 13:26

    So in other words, they’re using cheap crap, and it’s coming back and biting them in the a**.
    No surprise. I also no longer have sympathy for Dell, Sony, Panasonic, et al who have to eat millions of dollars in recalls. This is what happens when the beancounters and not the engineers are designing products. Penny wise, pound foolish.

  24. Gecko
    September 06, 2007 12:32

    It may be hard to test a battery non-destructively, but perhaps what is needed is to disassemble a random sample occasionally. That should pick up the counterfeit raw materials problem.

  25. Pelle van der Heide
    September 06, 2007 09:38

    Funny you should mention the Volt. The volt does not use lithium cobalt or tithium nickel manganese batteries, but A123′s phosfor based cells. These cells are much safer than the other chemistries. To see how safe look for the video where they drill a nail trough it on YouTube.

  26. Peter
    September 05, 2007 22:41

    Re;Lithium-Polymer-Battery(1400mAh 3.7V)power source for ECTACO Electronic Translation Dictionaries type PW800. This year I purchased the above (at almost Lap-Top price), with spare battery. However in the ‘off state’ the quiescent drain is about 10mA, resulting in a flat battery within a week, without switching on! On reporting this I was told that this is normal. If this is the’sleep mode’ then the product (made in China for USA) must be having night mares in an unknown language!
    I will be taking this further. The spare battery retains its charge ex-unit. Others must be experiencing this.
    I agree with Ray Throssell’s artical 5/9. Indeed it may be necessary to apply excessive volage to overcome internal resistance with current limiting.

  27. Raymond Throssell
    September 05, 2007 21:38

    I have come across a problem with battery packs such as used in laptops and portable DVD players.
    The battery pack appears to be completely dud, but is not!
    It will not charge.
    The reason is inside the pack is an electronic circuit which detects the state of the battery.
    It will not allow charging if the voltage has fallen below a set level or if the internal impedance is high.
    I have removed the casing to charge these cells directly from a current controlled power supply, and this always recovers the voltage and capacity, so that the laptop will allow normal charging.
    I think it is a very bad idea to have anything but a fuse and temperature cutout inside the battery compartment.
    Ray Throssell, Electronic Design Engineer.

  28. Graham
    September 05, 2007 14:50

    Whatever happened to NiFe cells? I came across these for engine starting in the mid ’60′s, chosen for their reliability.

  29. Adrian Davies
    September 05, 2007 14:17

    I remember the “memory effect” with Ni-Cd batteries but do Lithium batteries have a similar or more devious memory? I have had two laptop batteries fail, both when they were 13 months old and just out of warrantee. An expensive habit.

  30. Adrian Davies
    September 05, 2007 14:16

    I remember the “memory effect” with Ni-Cd batteries but do Lithium batteries have a similar or more devious memory? I have had two laptop batteries fail, both when they were 13 months old and just out of warrantee. An expensive habit.

  31. September 05, 2007 12:06

    Sadoway is nearly right when he points out, “if your MP3 player fries, you don’t get to listen to your favourite tunes,” but if it fries while it’s sitting in my trouser pocket and sets fire to Steve and the Twins then believe me THATS A PROBLEM!