back to article Tiny solid-state battery promises to pack a punch in pocket gadgets

Japan's TDK Corporation claims its new solid-state battery design has a hundred times the energy density of its previous products. The battery, which falls under TDK's CeraCharge lineup, has an energy density of 1,000 watt-hours per liter, the veteran tech corp claimed. That's apparently thanks to a newly developed material …

  1. John Robson Silver badge

    Halfway decent rechargable would be nice

    Rather than zinc air hearing aid batteries - the one set of batteries you really can't afford to not last a whole day (even if that is a longer than usual day due to travel etc).

    Put me down for two pairs, so that I can have a spare pair with me and switch them out when they run low.

    1. Andy_bolt

      Re: Halfway decent rechargable would be nice

      Fully agree. Solid improvements in hearing aid batteries would improve quality of life for users far more than incremental improvements in mobile phone battery life.

      1. Anonymous Coward
        Anonymous Coward

        Re: Halfway decent rechargable would be nice

        My NHS hearing aids use rechargeable batteries, working fine for over a year so far, and thats with bluetooth enabled.

        1. John Robson Silver badge

          Re: Halfway decent rechargable would be nice

          Six years on and my zinc air batteries are still going to recycling.

          To be fair, I had two reasons for the choice I made - the rechargeable versions didn't include a t loop receiver, and the individual charge duration wasn't enough to deal with a flight to the US...

          When I get replacements/upgrades I'll need to look at the battery technologies again, but they weren't enough for me back then.

          1. Roland6 Silver badge

            Re: Halfway decent rechargable would be nice

            > Six years on and my zinc air batteries are still going to recycling.

            You are overdue a replacement hearing aid!

            There is a large difference between a pre Covid digital hearing aid and the ones now being supplied by the likes of Addenbrookes, and with improved battery life…

            Similar applies to cochlea implants… I suspect much is due to the adoption of 5nm chips.

            1. John Robson Silver badge

              Re: Halfway decent rechargable would be nice

              "You are overdue a replacement hearing aid!"

              Yep, though my mother in law has had hers for ten years, still going strong.

              Mine still work very well... though I am interested in what the current state of the art is, and what the current NHS aids are like,

              1. Roland6 Silver badge

                Re: Halfway decent rechargable would be nice

                > Yep, though my mother in law has had hers for ten years, still going strong.

                They do seem pretty reilable, what I found interesting was the big jump between circa 4~6 year old (NHS) digital and current (since circa 4Q 2023) NHS digital. Audiology at places like Addenbrookes Hospital seem to be more with it than other centres (eg. My hospital, which is in the catchment for Addenbrookes cochlear implant services).

                From family evaluation, there was very little real improvement between a NHS hearing aid, of similar age to your mother in law’s, with the circa 2019 (immediately pre Covid-19) NHS digital hearing aid. Both were immediately given up once people tried the new digital hearing aids, which seem to have borrowed some ideas from cochlea implants and so can be better tuned to a persons ear and hearing condition ( and can be paired with a cochlea implant), plus the modern digital ones have better Bluetooth audio connection with mobile phones…

                Suggest you get yourself referred for cochlea implant assessment, where they will look at the options, as a better hearing aid is a lot cheaper for the NHS than a cochlea implant. At the worst, they will service your current hearing aids and give you a stack of batteries… plus you will get a better idea of how much your hearing has deteriorated…

                cochlea implants, whilst the latest generation (eg. Cochlear Nucleus 8 ) are a massive improvement, they do require effort to get the most out of, plus it’s can be a 3~4 year journey just to get the implant..

                1. John Robson Silver badge

                  Re: Halfway decent rechargable would be nice

                  "Suggest you get yourself referred for cochlea implant assessment, where they will look at the options, as a better hearing aid is a lot cheaper for the NHS than a cochlea implant. At the worst, they will service your current hearing aids and give you a stack of batteries… plus you will get a better idea of how much your hearing has deteriorated…"

                  Don't need an implant.

                  My hearing loss was rather traumatic (in the clinical sense), went from very, very, good (amateur audio engineer) to requiring bilateral aids in under ten days, and has been consistent since.

                  Current aids aren't NHS, so a referral is entirely reasonable to look at what hearing aids they currently offer, and what technology is now on offer

                  1. Roland6 Silver badge

                    Re: Halfway decent rechargable would be nice

                    > My hearing loss was rather traumatic (in the clinical sense), went from very, very, good (amateur audio engineer) to requiring bilateral aids in under ten days, and has been consistent since.

                    My condolences, that must have been a bit scary.

                    As I intimated implants aren’t for everyone and definitely not a quick solution. However, the assessment is thorough, one of the tests Addenbrookes did was to determine the level of nerve and brain (sound processing centre) damage, something the local hospital didn’t do (seems an obvious test, but…).

                    So definitely, I would agree it is wholly reasonable that you get checked out and take the opportunity to asses what the NHS now has to offer. For me the years of waiting and going through the cochlea implant process with my profoundly deaf cousin was an education in hearing, sound processing and interpretation of nerve induced sensations into bird song or words.

                    1. Roland6 Silver badge

                      Re: Halfway decent rechargable would be nice

                      Also, discovering just how poor my, as assessed by an optician and pilot training, excellent sight is. Learning BSL (it was our challenge/deal - I helped my cousin learn to hear, he helped me to sign) shows how poor/slow my ability to follow signing both visually and process the conversation is. I now agree with those who say we should be getting infant school children to sign, as it definitely develops the brain…

                      1. John Robson Silver badge

                        Re: Halfway decent rechargable would be nice

                        Yeah - if we could get it into primary schools that might help... but having done some BSL (more SSE, but still) for a while I know that without use it rapidly gets forgotten.

                        The ability to watch multiple things at once is quite useful though...

      2. Charlie Clark Silver badge

        Re: Halfway decent rechargable would be nice

        But the money is in the phones… If you look at many recent inventions and innovations you'll see that, aside from the ground breaking fundamental research, they're driven by the market. For example, it wasn't until it became fashionable for car manufacturers to want to reduce power for headlights, presumably to drive in-car entertainment, that money was spent developing LED lights. And we might never have got Li-Ion batteries if Sony hadn't been involved in the initial research.

        1. Jimmy2Cows Silver badge

          Re: Halfway decent rechargable would be nice

          LED headlights are brighter, require less power, and have a much longer life than the older halogen or xenon bulbs they replaced. For the same or greater brightness, they can also be much smaller, thinner, shaped to match the car's styling, compared to using bulbs. They can also be active matrix, selectively and dynamically modifying the beam pattern with respect to oncoming traffic.

          These are why bulbs are being ditched in favour of LEDs. Other benefits like requiring less power, so less alternator load and therefore slightly better fuel economy, and having more power available for other systems will be mostly incidental. Cars with high power entertainment systems just have a bigger alternator, thicker power cables, and higher capacity battery. Nothing to do with making more power available. The right alternator will provide the needed power.

          LEDs have been around for decades, but it took a while for LED technology to become viable for car headlights. Brightness, colour temperature, life span and cooling all had to be resolved first. Once they were solved, transition to LEDs was almost enevitable.

          1. Dave 126 Silver badge

            Re: Halfway decent rechargable would be nice

            They messed up up the colour temperature - it's too far into the blue. Its more dazzling than incandescent bulbs, and leads to greater eye strain for other drivers. The EU is investigating.

            It's hardly an insurmountable problem, it just requires different phosphors in the headlight assembly.

            1. Mage Silver badge

              Re:Its more dazzling than incandescent bulbs

              Also too bright!

              1. John Robson Silver badge

                Re: Re:Its more dazzling than incandescent bulbs

                Far, far too bright - and far too small, which increases the dazzle noticeably.

                Hate the modern trend of trying to make evening/night driving look like solar noon on the solstice - it also encourages drivers to only look for lights that resemble the sun rather than looking for clear road.

                1. Mahhn

                  Re: Re:Its more dazzling than incandescent bulbs

                  to true, I don't get how the auto industry missed that the LED lights they are using are SHORT wave, so they are not directional and scatter, which makes them painful to be driving towards. Which has started another industry of Driving Glasses to DEFEAT the LED bulbs.

                  Such poor planning by industry and total disregard for human health, all to make a buck. And those nondisfused LED break lights kids put in are horrid.

                  1. Denarius Silver badge

                    Re: Re:Its more dazzling than incandescent bulbs

                    worse.

                    In my bitter experience with trailers, Oz and European made, LEDS fail faster, more often than incandescent bulbs, cost way more to replace if possible, are not repairable as they are part of circuit boards with ICs and spares are not available. The LED might be OK, but the components on circuit board fail. Ironic that I have leds in 20 plus year old IT kit that work fine. Also above about LED headlights requiring night driving glasses that block blue. The locals have an inability to turn off their oversize spot lights that would be appropriate on a Dakar Rally vehicle, let alone drop to low beam. Just waiting for summer night that some Dukes of Harzard wannabe sets long grass on fire. Attrib to Ettomogah Pub cartoons

                2. PB90210 Bronze badge

                  Re: Re:Its more dazzling than incandescent bulbs

                  It's annoying that they make R/G/Y LEDs similar in brightness but blue LEDs have the intensity of the sun...

            2. Conundrum1885

              Re: Halfway decent rechargable would be nice

              Materials science like quantum dots are a potential solution and can be added to existing assemblies.

              Incidentally it is even easier to replace the phosphor with a QDOT panel likely deposited directly onto the optics so that the near UV light is downconverted at several points to get an even spread of light.

              The other interesting approach is "optical downconverters" that use a very high efficiency solar cell to directly drive a visible LED at the nanoscale, this also allows things like redundancy should the main emitter fail it can still do low brightness when energized with RF or direct DC drive like the LED filaments.

              I also looked into using laser diodes and a 395nm LD projecting onto a QDOT sheet is very efficient and easily shielded with redundant failsafes so none of the pump light can get out.

              Scanning the beam is also an option and on some new cars the LED array is controllable so beam width and other properties can be controlled with no moving parts.

          2. Charlie Clark Silver badge

            Re: Halfway decent rechargable would be nice

            You seem to have missed my point. LEDs have been around for decades, but it wasn't until the car industry got interested that things started to change. Rinse and repeat for most modern innovations, especially in healthcare.

            1. Like a badger

              Re: Halfway decent rechargable would be nice

              "You seem to have missed my point. LEDs have been around for decades, but it wasn't until the car industry got interested that things started to change. Rinse and repeat for most modern innovations, especially in healthcare."

              Sorry, I have to dispute that. LED's have slowly developed from low power, single colour pimples fit only for panel indicators, and what ultimately got them to the big time was the ability to display blue light. The push for that didn't come from car makers, it came from flat panel makers. Then, seeing that you could produce blue (and therefore white) light, domestic lighting makers got in on the act, looking for innovations to get say 800 lumens from a single fitting. I'd agree, car makers haven;'t been idle but needed about 1,600 lumens. They have supported some innovation, but the real breakthrough was the blue LED, and the car industry can't claim that.

          3. that one in the corner Silver badge

            Re: Halfway decent rechargable would be nice

            > LED headlights ... have a much longer life than the older halogen or xenon bulbs they replaced

            Well, unless they "accidentally" overdrive them, under cool them and shorten their working life.

            Big Clive has a few telling videos about reducing the power for all sorts of bright LED lighting, resulting in extended lifetimes (like, the life you'd expect an LED to have) with no significant loss of lighting effect from the p.o.v. of the human eye (the advantage of log versus linear responses).

          4. Roland6 Silver badge

            Re: Halfway decent rechargable would be nice

            > shaped to match the car's styling, compared to using bulbs.

            Wow! Just shows how important trivia wrt to function has become in the motor industry…

            But we knew that from the ads which have always been about feelings, just like perfume ad’s

    2. jmch Silver badge

      Re: Halfway decent rechargable would be nice

      1000 Wh/litre isn't a lot when the battery is so tiny... Estimating from the photo about 5mm square and maybe 2mm thick works out at a volume of about 0.05ml, which conveniently converts to 0.05Wh, or 50mWh of capacity. As best as I can work out, hearing aids consume on the order of 1mW, so a battery that size gives you 2 days. Essentially it means that just like with a phone, it has to be charged every day to avoid thinking about whether it was yesterday that I last charged it or the day before??

      On the other hand, having to plug it in every day is probably less a burden than having to change batteries every week, not to mention the financial and resource costs.

      And if they can scale that up, a phone-battery size (about 100 x 100 x 4mm) would be 40Wh - more than double even the highest-capacity current phone batteries in an approx 100g package

      And if they can scale that up even further, a car-battery size (eg 2000 x 1000 x 50mm) would be 100kWh - more than all but the longest-range current EVs, in an approx 300kg package (just cell weight, it would be at least 350kg when adding connecting cabling and electronics, but still much less than 500kg + current ones)

      In other words, small incremental increases like this build up over time

      1. John Robson Silver badge

        Re: Halfway decent rechargable would be nice

        If it could do 50 hours then I'd be on board - it's generally easy to charge overnight, since you don't wear the aids overnight.

        But a second set makes any decent battery life relatively low impact anyway.

        I change my Zinc Air batteries about every 4-5 days

  2. Nik 2

    Capacity

    A Panasonic CR2032 cell has about 225 mAh at 3 volts, or 775 mWh

    Volume is about 1cm^3, implying 775 Wh/litre

    Energiser's spec sheet gives 683 mWh/cc, so TDK's tech nis either much better than claimed or their current cells are rubbish...

    1. Andy 73 Silver badge

      Re: Capacity

      So, it beats the non-rechargeable batteries by a reasonable margin then? 1000 Wh/litre vs 775/683? And it's rechargeable - presumably with a reasonable life span. Sounds like an improvement to me.

      1. Mike 137 Silver badge

        Re: Capacity

        "the button cell type battery is due for a replacement"

        I wonder why. I recently replaced the time clock CR2032 in one of my audio recorders. The original came with the recorder in 2008 and was still working fine -- I just thought it was about time to swap it out in case of possible leakage (but actually none). So 16 years and still going strong -- hardly poor performance.

        1. Roland6 Silver badge

          Re: Capacity

          "the button cell type battery is due for a replacement"

          Probably because it and its mounting is relatively bulky. Plus you replace the battery not the device… ie. This battery is going to be easier to solder in…

      2. Nik 2

        Re: Capacity

        30-50% is a lot less than the 100x claimed in the headline, IMHO.

    2. Dave 126 Silver badge

      Re: Capacity

      Good catch!

      We can't rule out that a decimal point got shifted in-between the lab and and press release. Or maybe the marketing department read that it being good for 1,000 charge cycles makes it 1,000 more capacious.

      In fact if you dig further through TDK's product pages and PDFs, they don't really boast of its capacity, and instead are selling the tech on its high operating temperature range, its inability to leak toxic liquids, and its fire resistance.

      The first product to incorporate the tech was a Bluetooth cooking thermometer that you leave in the oven.

    3. tony72

      Re: Capacity

      Depending on the internal volume, but Duracell lists between 433 and 699 Wh/l for its MicroLithium coin cells, 555 for the DL2032, so seems about right.

      Still, a bit higher capacity *and* rechargeable is a nice upgrade, if not a game changer.

      1. Dave 126 Silver badge

        Re: Capacity

        Because these solid ceramic cells don't require the robust shells that conventional cells do, they may in practice exhibit a superior energy density. This advantage is less pronounced at larger volumes such as that of laptop batteries.

        Edit: Ninja'd by @Pete below!

    4. Pete 2 Silver badge

      Re: Capacity

      The case around a button cell takes up a considerable part of its total volume.

      I reckon that if only the active part of a button cell is considered, then the power per litre would be much greater. But just how the capacity of this solid-state battery was measured is am unknown variable.

      Although once these go on sale on Aliexpress, I forecast a vast improvement in their capacity. Up to 9800mAh, easily!

    5. petef

      Re: Capacity

      A Rayovac 13 zinc air button cell is typically used in heading aids.

      Its data sheet has 136 h at 2 mA and average 1.25 V giving 340 mWh. Volume is 0.26 cc implying 1300 Wh/L.

      1. Irongut Silver badge

        Re: Capacity

        The metal case round the cell takes up a large proportion of that volume, implying you're an idiot.

        1. Jimmy2Cows Silver badge

          Re: Capacity

          Bit harsh. Only real implication is they don't understand the intricacies of volumetric energy density.

          As noted lower down by katrinab, subtracting the volume of the casing will actually increase the Wh/l value... same Watt hours in a smaller volume.

          1. petef

            Re: Capacity

            My comment about Rayovac 13 was a reply to the figures for a CR2032 and so I adopted the same parameters.

    6. Mage Silver badge
      Boffin

      Re: Capacity

      Also some things using Silver Oxide, Alkaline or Lithium coin/button cells don't need to be rechargeable, they last for 1 to 8 years.

      The button/coin package was invented in the 1930s by Mallory (a Chemist) for mercury cells for grid bias, but saw volume use in WWII as power cessl for proximity fuze electronics because zinc carbon had a terrible shelf life. Later his company marketed the Alkaline cells (licence) that Eveready/NCC or UK Ever Ready invented but wasn't interested in. So successful he renamed the company Duracell. Later US Eveready did do the same with Energiser.

      I'll believe the TDK claims when I see products.

      Lithium rechargeable cells exist in larger coin packages and have poor shelf life and charge capacity compared with Primary Lithium cells at 1 to 20 uA current (the CR2032 shouldn't really have more that 500uA load, though 1mA is feasible. The UK supermarket price is at least x10 high, maybe x15 high!

  3. Jan 0 Silver badge
    WTF?

    Anode Free Battery

    OK, it's not related to this TDK battery, but I'd dearly love to know how you can have an anode-free battery? Do they mean a distributed anode?

  4. katrinab Silver badge
    Meh

    A quick Google suggests for a CR2032 from Panasonic:

    Volume: 1cm³

    Capacity: 0.675Wh

    That works out at about 675Wh/l, so the TDK is about the same

    If existing TDK batteries are only 10Wh/l, then that would explain why they are better known for the magnetic tapes than their batteries.

    1. Irongut Silver badge

      What is the volume of the actual cell inside the metal battery case? Definitely not 1cm3.

      1. katrinab Silver badge

        Which increases the Wh/l

  5. Paul Crawford Silver badge

    The Register couldn't easily find any watt-hour per litre specifications for button cells; we've asked TDK for clarification on this point.

    The golden rule for any data sheet is what is left out is important - as it means it is rubbish and they don't want it mentioned. Same for any company that only provided a data sheet under NDA - almost certainly what they have has some crap aspect they don't want compared.

    1. Dave 126 Silver badge

      > The Register couldn't easily find any watt-hour per litre specifications for button cells; we've asked TDK for clarification on this point.

      Translation: The Reg couldn't do the required calculations on easily obtainable data because their calculator's batteries have run flat.

      1. Irongut Silver badge

        More like they have no idea the volume of the cell inide a button battery and neither do you. The metal case does not have zero volume!

        1. Dave 126 Silver badge

          > More like they have no idea the volume of the cell inide a button battery and neither do you.

          Nobody was talking about the inside of the cell! The Reg said they "didn't know the power density of button cells."

          The shiny things that go in watches and hearing aids are not batteries [of cells], they are cells.

          As for case of the cell not having have zero volume, you'll see Pete 2 and I mentioned that hours before you turned up.

      2. Fruit and Nutcase Silver badge

        watt-hour per litre

        There is no unit for power in the The Reg Standards

        https://www.theregister.com/Design/page/reg-standards-converter.html

        A bit convoluted to derive it from what is there

        1. jmch Silver badge

          Base unit for energy is (as far as I can work out) kg.m2.s-2. Per volume (m3) would make it kg.m-1.s-2, which helpfully is the same as for pressure

          Sadly there is no official Register unit for time (suggestions???), but we DO have a unit for Force - kg.m.s-2

          Reg Unit for volumetric power density would be something like Norris per nanoWales

          That sounds all sorts of wrong (so it might be correct)

          1. StuartMcL

            Sadly there is no official Register unit for time ???

            According to the converter, there are two: Scaramuchi and Truss.

            See https://www.theregister.com/2022/10/21/truss_reg_standards/

        2. Androgynous Cupboard Silver badge

          Surely if you're measuring power per litre you need some sort of Buckfast-tonic base unit? One can gives enough power to destroy three plate glass windows on the highstreet, etc.

  6. alain williams Silver badge

    What about fire risk ?

    My first thought after reading "high energy density" was: will that not lead to more fires after they suffer a short circuit or something ?

    Is there some mitigation, or what ?

    1. Dave 126 Silver badge

      Re: What about fire risk ?

      They're based on solid ceramic layers, and are sold on their robustness and high temperature operating range.

      Since 2022 they've been used in Bluetooth cooking thermometers intended to be placed in ovens.

      1. Like a badger

        Re: What about fire risk ?

        "They're based on solid ceramic layers, and are sold on their robustness"

        How robust? Existing button batteries and the lithium canisters put in vapes are not easily damaged without intent and tools, but are a persistent source of fires in waste and recycling system - 1,200 instances in the UK over the past year. What happens when a solid state battery is physically damaged?

        1. Dave 126 Silver badge

          Re: What about fire risk ?

          > How robust?

          These TDK cells are layers of solid electrolytes sandwiched between ceramic layers, and they resemble surface-mounted microchips. Robust.

          Li-ion batteries are slightly squidgy sacks of gel, prone to bring punctured unless contained in a robust shell.

          You don't have to walk far along the pavements of Britain before seeing a vape that has been run over by a car, squishing the li-ion battery and exposing its contents.

    2. Charlie Clark Silver badge

      Re: What about fire risk ?

      There is little direct correlation between energy density and fire risk: any hydrocarbon fuel has a much, much higher energy density than any battery, but they're nearly all less of a fire risk than, say Li-Ion batteries. The chemical properties, particularly between the various components, is more important: sodium is more reactive than lithium, but Na-Ion batteries pose much less of a fire risk than Li-Ion.

      However, the underlying storage technology in a battery can have significant implications on the ability to scale because they essentially store electrical energy rather than the chemical sort: how and where the charge is stored is one of the main drivers behing solid state batteries.

      1. cyberdemon Silver badge

        Re: What about fire risk ?

        I'd say there is more of a correlation between (energy density * power density) and fire risk.

        Capacitors have a high power density but low energy density and low fire risk. Solid State batteries have a high energy density, low power density and low fire risk. Power-and-energy optimised lithium polymer batteries of the like used on drones and e-scooters on the other hand...

        Lithium Thionyl Chloride (Li-SOCL2) primary (non-rechargeable) batteries go up to 680Wh/kg and 1280Wh/l, but are usually fitted with a current limiter because of their propensity to go off like a bomb if abused..

        1. Flocke Kroes Silver badge

          Re: What about fire risk ?

          The spec sheet for tantalum capacitors includes a maximum discharge rate sometimes with a note that the device will catch fire if the discharge rate is exceeded. I accidently tested this by shorting one out with an oscilloscope probe. I was much more careful with the next prototype.

          (While I am here - not directly car battery tech: these cells a brittle so do not scale to large sizes.)

        2. Charlie Clark Silver badge

          Re: What about fire risk ?

          Well, what really matters is whether you're talking about electrical charge energy, as in batteries. Or chemical energy, as in fuel, or Li-Ion batteries when they start to burn.

          As I said, lots and lots of incredibly energetic and even potentially explosive fuel is perfectly safe if stored and handled correctly. Non-solid state batteries are, in a sense, inherently instable.

          1. Like a badger

            Re: What about fire risk ?

            if there's more energy in a solid state button battery replacement, it'll be more dangerous if swallowed, as the risk is purely electrical. Conventional button batteries are an existing safety risk for children. Replace them with something that stores more power and the risks will increase. This is wholly independent of the chemistry. For those who haven't seen it, there's a short video over at Child Accident Prevention Trust where they put a coin cell into a lump of chicken to show what happens.

          2. Androgynous Cupboard Silver badge

            Re: What about fire risk ?

            You can hold a lit match to a lifepo4 cell without risk, but try that with a liter of petrol and you will find your claim of stability for hydrocarbons goes out the window quite rapidly, along with anything nearby.

            Both have a lot of energy, and can give it up rapidly. The question is how likely that is to happen by accident. That’s an engineering question, but it doesn’t mean batteries are inherently less stable than petrol.

            1. Roland6 Silver badge

              Re: What about fire risk ?

              > You can hold a lit match to a lifepo4 cell without risk, but try that with a liter of petrol

              Repeat using diesel and if your budget and connections permit JP-7…

              1. Fruit and Nutcase Silver badge

                Re: What about fire risk ?

                +1 for JP-7, developed for the SR-71

  7. petef

    Battery University is an extensive resource for all things about batteries.

  8. Anonymous Coward
    Anonymous Coward

    A rechargeable button cell would be useless without a compatible charger.

    Sure, rechargeable would be nice, but has anyone seen a button-cell charging station for retail sale? Because I haven't. Sure, it's just a matter of repackaging a cylindrical-cell (NiMH, Li-ion, etc.) charger with some new contacts / battery holder and adjusting the voltage, but it's still a "new" product that involves additional industrial design/engineering (package for retail, assembly line, etc.). All this takes money and time (and employees' time IS money). Some battery/charger company will have to be the first to gamble on attempt it after the homebrew geeks figure it out.

    1. Dave 126 Silver badge

      Re: A rechargeable button cell would be useless without a compatible charger.

      The charging circuitry is likely to be built into the device that the cell is intended to go in. Indeed, TDK's existing solid ceramic cells have been surface mounted to a PCB.

      In some scenarios such as devices intended for near continuous operation (e.g hearing aids), it might be desirable to have swappable batteries - so perhaps a charger can be incorporated into the hearing aid case, much as wireless earbuds are charged today.

      1. Charlie Clark Silver badge

        Re: A rechargeable button cell would be useless without a compatible charger.

        I quite like the idea of Exeger's Powerfoyles for consumer electronics: ambient light is often sufficient for many devices.

      2. Roland6 Silver badge

        Re: A rechargeable button cell would be useless without a compatible charger.

        > “In some scenarios such as devices intended for near continuous operation (e.g hearing aids), it might be desirable to have swappable batteries - so perhaps a charger can be incorporated into the hearing aid case, much as wireless earbuds are charged today.“

        Already a feature of many cochlear implants and some newer hearing aids. Interestingly the “overnight” charger case is also a dehumidifier and hygiene “bath” to help dry out the circuitry, prevent bacteria growth and so prolong life; things missing from the earbud charging cases…

  9. Richard Tobin

    TDK... oxide based...

    ... they're made out of old SA90 cassettes, aren't they.

  10. Denarius Silver badge
    Unhappy

    Once more, with feeling

    another breakthru coming Real Soon Now. Or more likely, incremental improvements over 5 years

    1. Roland6 Silver badge

      Re: Once more, with feeling

      The breakthrough will probably happen in circa 5 years, as it will take that long to develop battery/cell packaging, get approvals, redesign to enable mass production.

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

Other stories you might like