back to article Boffins say they've got Lithium batteries the wrong way around

US boffins are overturning the understanding of how Li-ion batteries charge, by watching the behaviour of individual molecules as they absorb charges. It's long been assumed that a battery charges fairly uniformly – in other words, that electrons are distributed evenly across the charge-carrying material as the battery charges …

  1. Faux Science Slayer

    Green Prince of Darkness

    Don't expect quantum leaps of performance, only a marginal change in energy density. Chemical storage batteries seem to have a technical limit of 400 recharge cycles, physical limits weight/output and slow recharge cycles. Since DC generation from wind and photovoltaics is sporadic, the need storage for has included batteries, see "Green Prince of Darkness" for info on PV solar cells and batteries, at the FauxScienceSlayer site.

    1. Trevor_Pott Gold badge

      Re: Green Prince of Darkness

      A) that's barely cogent

      B) what do attacks on renewables have to do with battery tech?

      C) your information is a combination of wrong, cherry picked and sadly out of date.

      In all, 7/10. You have mostly decent grammar, there's no random capitalization, no caps lock and no excessive, repetitive punctuation. Once more, with feeling, perhaps?

      1. Michael Wojcik Silver badge

        Re: Green Prince of Darkness

        A) that's barely cogent

        I suspect you meant "that's barely coherent". It's not cogent at all - unless you're using "cogent" in the sense of "pertinent", but usually when it's employed that way it's something of a term of (rhetorical) art, where it means not just relevant to the issue at hand but a significant contribution to supporting the writer's thesis. And I think "barely cogent" in that sense gives FSS too much credit.

        1. Trevor_Pott Gold badge

          @Michael Wojcik

          It was (sort of) coherent. It wasn't cogent. I got what he was trying to say, just not quite why it was relevant to the discussion at hand. It had batteries. The article had batteries. That's barely related. The rest was flying off into la-la land.

    2. Terry Barnes

      Re: Green Prince of Darkness

      "Since DC generation from wind and photovoltaics is sporadic"

      I believe the sun's output is pretty reliable. Life on our planet rather depends on it.

      1. Def Silver badge
        Coat

        Re: Green Prince of Darkness

        ...the sun's output is pretty reliable...

        While I definitely do not want to be accused of feeding the troll, I should point out that while the sun's output is pretty reliable, so is the day/night cycle of our little dust ball (I understand some people are even attempting to predict at what time the sun will rise and set on any given day). On the other hand, clouds, generally speaking, are not so reliable.

        1. Michael Habel Silver badge

          Re: Green Prince of Darkness

          On the other hand, clouds, generally speaking, are not so reliable.

          ICWYDT

        2. ItsNotMe
          Coat

          @ Def

          ...the sun's output is pretty reliable...

          Maybe...maybe not. Nothing lasts forever you know.

          "The sun has used up about half of its hydrogen fuel in the last 4.6 billion years, since its birth. It still has enough hydrogen to last about another 5 billion years."

          http://www.space.com/14732-sun-burns-star-death.html

          Nearly half used up kids. Better start planning now for a major move to another galaxy. Can't start too early after all.

          Mine's the one with the SpaceX tickets in the pocket.

          1. Paul_Murphy

            Re: @ Def

            >Better start planning now for a major move to another galaxy

            A more local star system would be a better bet, and a slightly further away one should be sufficient unless FTL transport is deemed to exist in which case a galaxy would be another option.

            1. DropBear
              Trollface

              Re: @ Def

              Oh come on now, really - we know full well the whole place is set to collide with the Andromeda galaxy; do you seriously want to haul your furniture around, like, every month?!? We need to do this properly and get the hell out once we're up and moving anyway...

          2. gotes

            Re: @ Def

            "The sun has used up about half of its hydrogen fuel in the last 4.6 billion years, since its birth. It still has enough hydrogen to last about another 5 billion years."

            So we're only a few hundred million years away from "peak sun"? Yikes.

          3. jemmyww

            Re: @ Def

            However, the luminosity rises by 1% every 100 million years, so while the sun might be around and burning brightly for as much time as it has already, life on earth only has 600mil to 1.2bil years left. Unless maybe we soak it all up with solar power?

            https://en.wikipedia.org/wiki/Future_of_the_Earth

        3. Terry Barnes

          Re: Green Prince of Darkness

          "On the other hand, clouds, generally speaking, are not so reliable."

          Agreed. But you'd be surprised how little of the earth's surface, near the equator, would need to be covered in solar panels to provide 100% of global energy requirements 24/7 - even with clouds. There's "a bit of work" required to make that happen, but it's feasible - meaning we'd use batteries for portable devices (like cars) rather than to smooth sporadic grid input.

          1. Oninoshiko

            @terry Barnes

            In theory that may be true, but it would first require a world-wide power grid.

            I suppose if you where going to try to to a sidewalk sized path of photo-voltaics around the planet at the equator, hooking into grids for the major contents wouldn't be too hard, you still have to contend with Europe and Scandinavia's power is now coming by way of Africa, I suppose the middle-east would be a possibility as well. The US and Canada's power would be coming through Colombia and Mexico. South America wouldn't be do bad, the strip would go through Brazil, Colombia, and Venezuela.

            I guess you are planning on building a lot of wires over (under?) the ocean to connect to places like Australia.

            All in all, I think this would go over about as well as a lead zeppelin.

    3. imanidiot Silver badge

      Re: Green Prince of Darkness

      I (more or less) get what you're saying. I just don't get why it's relevant. The article doesn't really speak about quantum leaps of performance or massive changes in recharge cycle limits. Just prevention of damage to cells within the current cycle life. Even just extending the average lifespan of a lithium cell is a worthwhile cause with the amount of use they are currently getting.

      1. a53

        Re: Green Prince of Darkness

        Particularly if aircraft stop catching fire.

    4. ilmari

      Re: Green Prince of Darkness

      High cycle life.

      High power density / fast charge

      High energy density

      Cheap.

      Pick any two features.

  2. frank ly

    @ 'Faux' Science Slayer

    From one of your previous posts:

    " ... i started writing Satire....posted at Canada Free Press and even more at my website..."

    It's interesting to see how you've developed.

    1. Dave 126 Silver badge

      Re: @ 'Faux' Science Slayer

      I like my satirists to be smarter than me, well informed and skilled in their art. Chris Morris, Peter Cook, Steve Bell, Jon Stewart, Sacha Baron Cohen, Rory Bremner, The Onion, whoever...

      People who adopt a cause - whatever it is - to merely promote themselves are a part of the problem, since they just add to the noise.

      Maybe FSSlayer should leave the issues surrounding energy storage to engineers? Aside from issue of renewable energy generation, there are some solid reasons for smoothing out the supply and demand of energy over a day / week / year. Batteries of any chemistry will only play a limited role in this - I'm not surprised that FSSlayer is ignorant of pumped hydro schemes and the like.

  3. grumpy feline
    FAIL

    Scientists...pah

    Did scientists really assume "that a battery charges fairly uniformly"? Which scientists? I wish to mock such wilful ignorance.

    1. Paul Kinsler

      Re: assume "that a battery charges fairly uniformly"?

      As a scientist, I have to say that that's exactly the sort of simplifying assumption I'd start with. Not that I would "know" or even believe that it was actually true, just that it made building a model of $WHATEVER a little bit simpler. Later on, when it's clear that the model isn't good enough, you revisit all those convenient simplifying assumptions and decide which ones need to be de-simplified. Usually, trying to build a complicated model straight off is a recipe for confusion. Would you rather be asking yourself the question "which bit of this really detailed and complicated model isn't working?", or "which bit of this fairly simple model needs to be improved?".

      That said, other scientists may differ in their approach.

      1. Dave 126 Silver badge

        Re: assume "that a battery charges fairly uniformly"?

        What Paul Kinsler said.

        http://xkcd.com/793/ 'Physicists':

        "You're trying to model the behaviour of a <complicated system>? Just model it as a <simple object>, then add some secondary terms to account for <complications I just thought of>. . . Easy, right? ... Why does your <your field> need a whole journal, anyway?"

        [Liberal Arts majors may be annoying sometimes, but there is NOTHING so obnoxious as a physicist first encountering a new subject]

        Sidenote: Randall 'XKCD' Munroe was interviewed on BBC Radio 4's 'Today' programme this morning - it was about 8:40 am for those who skip through podcasts.

      2. 2+2=5 Silver badge
        Coat

        Re: assume "that a battery charges fairly uniformly"?

        > That said, other scientists may differ in their approach.

        So what you're saying is that scientists make simplifying assumptions about the way scientists make simplifying assumptions?

    2. Mage Silver badge

      Re: Scientists...pah

      It's well known that charging and discharging isn't uniform. That's why NiCd get dendrites.

      But interesting research to quantify it.

    3. fearnothing

      Re: Scientists...pah

      Physicists in general, obviously. This is just the electrical version of a physicist predicting the outcome of the Royal Ascot - provided that the horses are all perfectly spherical, perfectly elastic, and moving in a vacuum.

    4. ilmari

      Re: Scientists...pah

      Ghus is kinda similar results to similar research in LiFePo4 cells, where it was found that extremely fast charging can reduce the wear and tear on the cell.

      Fascinating stuff!

  4. Elmer Phud
    Boffin

    "Advanced Light Source Synchrotron."

    Don't give a toss what it does but with a name like that I want one!

    1. Dave 126 Silver badge
      Coat

      Re: "Advanced Light Source Synchrotron."

      You can buy them from Maplins for about £20, sold as 'Disco lights that pulse in time to your mp3 player'.

      1. Yet Another Anonymous coward Silver badge

        Re: "Advanced Light Source Synchrotron."

        I think those are Advanced Light Source Syncopation

  5. Mage Silver badge

    What?

    This was known AGES ago about Alkaline cells (which unlike Zinc Carbon can be somewhat or entirely recharged if not discharged too much).

    I was sure I read it a year ago about Lithium Ion cells.

    1. Charles 9 Silver badge

      Re: What?

      About the dendrites? Yes, that's supposedly the bug-a-boo about both recharging techs. I recall that it's a disturbing tendency with alkaline batteries which is why the idea has since dropped (you don't get enough recharges out of it to be worth it). And dendrites have been fingered in more than a few spontaneous Lithium combustions. I recall the research shows that improper charging is a big factor in that, which means this research could help to minimize the phenomenon.

      1. ilmari

        Re: What?

        Mostly, li-ion fires can be divided into 2 causes: impurities introduced during manufacturing, and bad battery management systems.

        Unfortunately, batteries seem to be poorly understood by most electrical engineers, so the amount of flawed battery management systems out there is rather huge.

        Still, the 'rules' are pretty simple: Don't go below 2.80V, don't go above 4.20V. Ever. Not even for a millisecond.

        Our clever cost-aware EE will then think "I've got 3 in series, so that means I need to stay between 9V and 12.6V. This is wrong, he needs to monitor all 3 cells individually. There will never be cells matched exactly enough, and stay matched throughout their service life.

        So, each cell must be monitored individually. On discharging, the device must shut off when the weakest cell reaches the minimum allowable voltage, or sooner. On charging, the charging current must be reduced when the fullest cell reaches maximum permissible voltage. Preferably you have a circuit that can bleed off some charge from the fullest cells, so that all cells can be charged full.

        The EE that reads the datasheet closely enough, will notice that samples if cells are put through overdischarge and overcharge testing, wherd they are taken outside of the permissible voltage range, and demonstratedly don't explode, smoke, or emit excessive heat. He will then make the assumption that the limits are more of a guideline for best cycle life, and the worst that will happen is that the battery dies a bit sooner, and the customer needs to buy a new battery or device sooner.

        While it's true thay li-ion cells must withstand such tests without failure, they only need to do it once. That is, one test is performed once, and the specific cell in question is never used again.

        The reason for this is that every deviation outside the safe range inflicts accumulating damage to the cell. Accumulating meaning that while a 'small' deviation from the safe range might not cause problems the first time, it could cause issues the 10th time or the 200th time it happens.

        At one extreme voltage, the copper inside the cell starts dissolving. If this process reverses, you get conductive copper in random places, potentially causing short circuits, or a string of thin copper might carry current, cause heating, and ignite the cell.

        At the other end, the battery evolves metallic lithiun, which is the equivalent of the petrol in your car turning into nitroglycerine. Ungood.

        1. david 12

          RE: nitroglycerine.

          >At the other end, the battery evolves metallic lithiun,

          >which is the equivalent of the petrol in your car turning

          >into nitroglycerine.

          Metalic Lithium contains both an oxidiser and an oxidant? Allowing it to release energy without using an external oxidiser like 'air'?

          I wish people wouldn't casually compare explosives with single components of two-part reactions.

          1. Charles 9 Silver badge

            Re: RE: nitroglycerine.

            "Metalic Lithium contains both an oxidiser and an oxidant? Allowing it to release energy without using an external oxidiser like 'air'?"

            Actually, yes. It is capable of producing what's called a self-oxidizing fire. Certain other metals like magnesium have the same properties, as does thermite by design. Plainly put, asphyxiants don't work on them which is why they can burn even in oxygen-poor environments like underwater or even in vacuum.

            1. david 12

              Re: RE: nitroglycerine.

              Cooked Lithium Batteries are self-oxidising.. To my knowledge, "Metalic Lithium" is not "self-oxidising".

  6. Loyal Commenter Silver badge

    Electronics 101

    "Charge congregates in the pointy bits."

    Principally because free electrons are inclined to get as far away from each other as they possibly can, being negative little bastards.

    1. Random Yayhoo

      Re: Electronics 101

      That's a bit harsh. The elfin electron has done quite a bit of good for us. I have a few in my shirt pocket, I count each as he or she goes off to school. Just because of the unfortunate naming of their charge, people delight in bashing them about. If they were instead positrons, a mighty row would ensue!

  7. Anonymous Coward
    Joke

    Cutting up charged batteries

    I await the next, explosive instalment.

    Joke Alert, because some people are just so.... GERMAN!!!

  8. Ugotta B. Kiddingme
    Pint

    good stuff

    THIS is why I read The Register.

    Well, that and BOFH... cheers!

  9. Stevie Silver badge

    Bah!

    Finally, scientists do real science!

    Bravo!

  10. Anonymous Coward
    Anonymous Coward

    RE. Re: Green Prince of Darkness

    A little while back I "invented" a way to read charge state in LiFePO4 cells by using magnetic hysteresis after observing that charge state seemed to affect how susceptible to magnetism the cell was.

    Not that crazy as iron (Fe) is magnetic and it would behave a lot like iron filings in bulk.

    Also relevant, "dead" LiFePO4 cells can be revived using a weak degaussing magnetic field to heat it up (carefully) or an oven will do if you make sure it never ever goes above 65C.

    I determined that if the cell is below 0.9V for more than 24 hours it is dead forever no matter what you do as copper shunts form and will eat up capacity, however between 1.25V and 2.2V (full discharge) it comes back to life.

    This only verifiably works with D-X 1.2Ah 18650 FePO4, tried other Far Eastern manufacturer's cell but it didn't work; still using the above now and no dead cells yet (!)

    Still trying to find a way to bring back dead Li-Ions, but no luck yet.

    Even below 1.9V they usually die permanently and no amount of hacking will bring them back and it is dangerous to try due to Li+ plating inside the cell.

    LiPo (model packs) are notoriously finicky beasts and die for other reasons such as gassing and reactions with poorly insulated Al casings.

    Note: FePO4 are used in the OLPC due to the longer lifetime and resistance to overdischarge.

  11. Frogmelon

    Trees, fractals, lightning, pachinko..

    'scuse me while I go and contemplate the oneness of Li-ION batteries with the universe.

  12. Anonymous Coward
    Anonymous Coward

    Re. LiFePO4

    Apparently LiNi (variant of Li-Ion) have interesting magnetic properties.

    As nickel is somewhat paramagnetic ie can be affected by magnetic fields in theory a lot of broken e-bike packs could be repaired without opening them or replacing cells.

    I have one of these here, half the cells are below the threshold of 2.6V ranging from 0.9V to 1.8V and one pack of four is at 0.0 so that is probably stuffed :-(

    If I can get the dead cells back to life then it would serve as an interesting experiment and probably be worth writing a paper on.

    fwiw: controller b0rked causing burnination of a resistor, and as a result none of the cells were charging.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2020