back to article A good kind of disorder: Boffins boost capacitor tech by disturbing dipoles

A new approach to materials engineering promises to overcome the limitation of capacitors commonly used in smartphones, displays and electric vehicles, according to a study published in Nature. Different approaches to storing energy in electric circuits have their trade-offs: lithium-ion batteries can store a lot of energy but …

  1. cyberdemon Silver badge
    Pint

    frustration-modulated

    A good description for all of us these days

  2. Andy E
    WTF?

    Breakdown?

    This statement "the number of charge–discharge cycles that occur before breakdown" got me thinking. Are manufacturers building circuit boards with components that they know are going to fail?

    Whats the limit for charge–discharge cycles before breakdown occures and is the breakdown catastrophic?

    1. Ian Bush

      Re: Breakdown?

      Of course they are! But the question should not be "will the magic smoke escape" but "how long before we expect the magic smoke to escape"

      1. David 132 Silver badge

        Re: Breakdown?

        "...and will that be one day after, or - heaven forbid - one day before, the warranty term expires?"

        Edit: D'oh. NXM beat me to the joke, in the very next comment down. Ignore me.

      2. Missing Semicolon Silver badge

        Re: Breakdown?

        Wow. So the old thing where vintage gear will last for decades if the capacitors are good will come to an end, as the new capacitors will fail after a year or two?

        Enshittification of hardware proceeds apace.

    2. NXM

      Re: Breakdown?

      Of course! How else can you ensure the product breaks exactly a week after the guarantee runs out?

      1. This post has been deleted by its author

      2. herman Silver badge

        Re: Breakdown?

        The rep of a clothes dryer once was very angry with me and insisted that I must have done something to it to make it fail under warranty. He insisted they are designed to fail 6 months after, not before. Asked him how long the new motor will last - Oh, the new one will last forever!

      3. eldakka

        Re: Breakdown?

        > Of course! How else can you ensure the product breaks exactly a week after the guarantee runs out?

        Luckily, depending on your jurisdiction, this may be irrelevant and you may still be covered, for example in Australia, according to the ACCC Broken but out of warranty? Your consumer guarantee rights may still apply (excerpt):

        Common statements that may be misleading

        Here are some statements to watch out for, and an explanation of what consumers’ rights are.

        • Your product is out of warranty, so we can only repair it for a fee.

        This isn’t right. Consumer guarantees are automatic and are separate from any voluntary warranty, manufacturer’s warranty, or extended warranty. Consumer rights can last longer than warranty rights, and you can ask for a repair, refund or replacement after the warranty has expired.

        • No refunds under any circumstances.

        This isn’t right. If your product has a major problem, under the consumer guarantees you have a right to choose a refund.

        • To be eligible for a refund, you must return the product within 10 days. Refunds are not available under any circumstances after this time.

        This isn’t right. Businesses can’t apply a time limit on your rights to notify them or return a faulty product.

        • You will need to contact the manufacturer to have this issue resolved.

        This isn’t right. As a first step you should contact the business that sold you the product to explain the problem. The business can’t refuse to help you by telling you to contact the manufacturer.

        • If you don’t buy the extended warranty, you’ll have no protection once the 12-month warranty expires.

        This isn’t right. Consumer guarantees are separate from any warranties, and they may still apply after a warranty has expired.

        • We understand your concern that if you were made aware about this fault beforehand, you would not have purchased the product. We can offer you 50 per cent of the original purchase price as a goodwill gesture.

        This isn’t right. If your product has a major problem, a refund should be the full amount you paid.

        • The damaged item must be returned in its original packaging to receive a refund.

        This isn’t right. If your product is faulty, you don’t have to return the product in its original packaging to seek a refund.

        • We identified the screen is cracked on your product. The warranty doesn’t cover damaged screens, so we can’t help you today.

        This isn’t right. Even if your voluntary warranty, manufacturer’s warranty, or extended warranty doesn’t cover the specific problem, it may still be covered under the consumer guarantees.

        1. David 132 Silver badge
          Happy

          Re: Breakdown?

          Clearly not an authentic quote from an Australian website - doesn't have liberal use of the c-word!

          Also I'm highly disappointed that they didn't have:

          "

          • The front fell off.

          That isn't typical, we'd just like to make that point.

          "

          1. A.A.Hamilton

            Re: Breakdown?

            Actually, in a way, it is typical: the original wording included that clause, but just like every other Government car, inevitably the front ... well you know the rest.

    3. JamesTGrant Bronze badge

      Re: Breakdown?

      Anyone with a Sinclair ZX spectrum in the attic either knows this already, or will find out when they next try powering it up…

      1. Jet Set Willy

        Re: Breakdown?

        I tuned my old 128k Spreccy on about 3 years ago and it worked perfectly.

        Well, the computer part did. Unfortunately the drive belts in the built in tape deck had perished so I could't load anything, just mess about in Basic.

    4. cyberdemon Silver badge

      Re: Breakdown?

      Everything fails eventually, especially capacitors, and especially bulk storage capacitors i.e. where there is a space/cost constraint against the energy they need to store

      Ceramic and Tantalum caps can suffer dendritic growth, which kills them over time if they are used close to their max voltage rating. To make caps last longer, you can overspecify their voltage rating but that adds cost and size. Temperature is also a factor, and the manufacturer will have a reliability curve and a special more expensive series for extended temperature range.

      Any caps connected to the mains e.g. on the hot end of power supplies will experience transients that could exceed their rating too.

      Is it catastrophic? For tant/mlcc usually yes. They can fail short and explode violently. Electrolytics are usually a bit more forgiving and tend to fail open

      HV MLCCs (multilayer ceramic caps) are especially prone to failure near their voltage rating, because they are strings of capacitors in series. The smallest mistolerance in manufacturing, or cycle aging, can mean that one cap in the stack gets a higher voltage than the others, it then fails short, the others then see a proportionally higher voltage, and then you can get a cascade effect

      1. Ball boy Silver badge

        Re: Breakdown?

        ...and why people restoring old HiFi gear (especially) will often start their task by 're-capping' the beast. It's not an upgrade: it's simply to replace the components that degrade the most with age. I have a tube (valve) radio amp that's been sitting idle for years that I keep meaning to bring back to life...that monster has a cap isolating the 1.2KV anode from the antenna feed so even a partial failure there could prove very interesting indeed!

      2. cyberdemon Silver badge

        Re: Breakdown?

        One thing I forgot to mention is ripple current i.e. the average charge and discharge current, which depends on the frequency, capacitance and depth of discharge. You can use a cap within its voltage rating but if you charge and discharge at too high a frequency then it will age faster, higher still and it will overheat and fail. Again all this will be on the datasheet from any reputable manufacturer

      3. Anonymous Coward
        Anonymous Coward

        Re: Breakdown?

        Ceramic caps also have thermal stress induced failures. Being ceramic, they're brittle so can fracture when heated and cooled - or put under any mechanical stress really. This isn't great for a component that has to be soldered to a PCB.

        1. short

          Re: Breakdown?

          If you care, you can get your ceramic caps fitted with a teeny-tiny interposer PCB to reduce the stresses a bit.

          https://uk.rs-online.com/web/p/mlccs-multilayer-ceramic-capacitors/1873612

          Mostly it's to stop their inevitable piezo effects making the PCB flexing and making annoyingly audible noise, though. You can also get them on metal legs, or with 'soft' terminations to reduce the stresses.

          1. Missing Semicolon Silver badge
            Happy

            Re: Breakdown?

            Maybe they could put the capacitors on little wire legs to isolate them. Novel, eh?

    5. This post has been deleted by its author

    6. Kevin McMurtrie Silver badge

      Re: Breakdown?

      MLCC, to the best of my knowledge, never fail unless limits are exceeded. They're specifically used because they are compact and rugged compared to other capacitors.

      Capacitors with different uses are built with entirely different materials. That's where this article gets fuzzy. It sounds like they're talking about power filter capacitors. These tend to be expensive and mechanically fragile, so they rarely replace big electrolytic capacitors at this time.

  3. Anonymous Coward
    Anonymous Coward

    Transportation

    I was impressed by supercapacitors driving trams in Spain - No overhead wires!

    https://www.youtube.com/watch?v=VMRWnYYhi2Y

    1. cyberdemon Silver badge

      Re: Transportation

      No overhead wires at all? Or just between gantry sections?

      1. Big_Boomer

        Re: Transportation

        They charge the SuperCaps at each tram stop using an overhead rail and a raisable commutator, then use the stored energy to get to the next stop. Clever system but I imagine the SuperCaps lifetime is going to be short given how they are used. Personally I would design the commutator to stay up and design the overhead rail at each tram stop with a taper to pickup the commutator. Raising and lowering it constantly is going to wear out the mechanism rapido!

  4. FrogsAndChips Silver badge

    Applications?

    As far as I understand, these improved capacitors will not replace Li-Ion batteries, so what kind of improvements can we expect in our phones from this capacity (no pun intended) to discharge more 'quick' energy?

    1. Ball boy Silver badge

      Re: Applications?

      Aside from being able to make smaller caps, one advantage I can see is better decoupling: the faster you can 'sink' a spike or unwanted waveform, the better.

    2. cyberdemon Silver badge

      Re: Applications?

      Smaller, more powerful SMPS enabling things like higher voltage on USB-C to charge phones quicker, would be one.

    3. HuBo Silver badge
      Gimp

      Re: Applications?

      Trendy bluetooth-connected disciplinary collars for fashionable security guards?

  5. Ball boy Silver badge

    Speaking of caps...

    Slightly off-topic - but as junior techs in a long-gone circuit fabrication shop, our party trick was to wedge a big smoothing electrolytic cap between two filing cabinets and reverse-connect it to a beefy bench PSU. When the remote start was flipped, the resulting 'bang' occasionally threw enough material up to discolour the ceiling tiles. Made the office stink something awful, too, but it didn't half make us giggle when one gave up the ghost in spectacular style!

    1. David 132 Silver badge

      Re: Speaking of caps...

      I may have mentioned this before but waaaay back several decades ago, in a Physics class at my school near Chester, we were learning about capacitors, and had been given the standard educational selection of electrolytics with which to perform the assigned experiments. The teacher was talking to us - a whole class full of shiny-faced, attentive schoolboys. Except for one kid on the very back row of the benches, who was amusing himself by clandestinely daisy-chaining as many capacitors as he could, and charging them all from the 12V bench supply.

      Clandestine, that is, until there was a very loud "BANG", and we all spun around... to see our classmate doing his very best to look innocent, as white snowflakes of electrolytic material drifted down onto him like dandruff.

  6. DS999 Silver badge

    Three times the energy density

    Is nothing. They are still far far behind batteries in everything except rate of energy delivery and number of cycles, and aren't going to disrupt anything. What it might do is reduce the size of the caps which is useful in smartphones.

    There was a lot of hype 20 years ago about capacitors able to eventually replace batteries, but nothing came of it. Partially because the research never panned out as well as the hype, but mostly because battery technology received orders of magnitude more investment and improved so quickly in price/performance any hope of displacing them evaporated.

    1. ChrisC Silver badge

      Re: Three times the energy density

      It's not nothing though, as your closing comment in that opening paragraph suggests - forget about the comparison with batteries, and focus on how this could benefit products which presently use capacitors (in some cases a significant number of them) either in terms of being able to deliver higher levels of capacitance within the same physical footprint, or in being able to deliver the same levels in smaller footprints, or potentially even in being able to deliver capacitance in places where you had no chance of getting it at all.

      Is it a revolutionary leap forwards, no. Is it a useful, and by the sounds of it, something that actually does stand a good chance of making it into production, evolutionary step forwards in the continual improvements those of us faced with trying to come up with ever more efficient product designs very much like to see from component suppliers? Oh yes.

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