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Power Science

New Aluminum-Sulfur Battery Tech Offers Full Charging In Under a Minute (mit.edu) 116

According to a new paper published in the journal Nature, researchers at MIT describe new aluminum-sulfur batteries that are made entirely from abundant and inexpensive materials and can be charged in less than a minute. "The new battery architecture, which uses aluminum and sulfur as its two electrode materials, with a molten salt electrolyte in between, is described today in the journal Nature, in a paper by MIT Professor Donald Sadoway, along with 15 others at MIT and in China, Canada, Kentucky, and Tennessee," reports MIT News. The caveat with this new kind of battery is that it requires a variety of molten salts that need to be "close to the boiling point of water." From the report: In their experiments, the team showed that the battery cells could endure hundreds of cycles at exceptionally high charging rates, with a projected cost per cell of about one-sixth that of comparable lithium-ion cells. They showed that the charging rate was highly dependent on the working temperature, with 110 degrees Celsius (230 degrees Fahrenheit) showing 25 times faster rates than 25 C (77 F). Surprisingly, the molten salt the team chose as an electrolyte simply because of its low melting point turned out to have a fortuitous advantage. One of the biggest problems in battery reliability is the formation of dendrites, which are narrow spikes of metal that build up on one electrode and eventually grow across to contact the other electrode, causing a short-circuit and hampering efficiency. But this particular salt, it happens, is very good at preventing that malfunction. The chloro-aluminate salt they chose "essentially retired these runaway dendrites, while also allowing for very rapid charging," Sadoway says. "We did experiments at very high charging rates, charging in less than a minute, and we never lost cells due to dendrite shorting."

What's more, the battery requires no external heat source to maintain its operating temperature. The heat is naturally produced electrochemically by the charging and discharging of the battery. "As you charge, you generate heat, and that keeps the salt from freezing. And then, when you discharge, it also generates heat," Sadoway says. In a typical installation used for load-leveling at a solar generation facility, for example, "you'd store electricity when the sun is shining, and then you'd draw electricity after dark, and you'd do this every day. And that charge-idle-discharge-idle is enough to generate enough heat to keep the thing at temperature." This new battery formulation, he says, would be ideal for installations of about the size needed to power a single home or small to medium business, producing on the order of a few tens of kilowatt-hours of storage capacity.

For larger installations, up to utility scale of tens to hundreds of megawatt hours, other technologies might be more effective, including the liquid metal batteries Sadoway and his students developed several years ago and which formed the basis for a spinoff company called Ambri, which hopes to deliver its first products within the next year. For that invention, Sadoway was recently awarded this year's European Inventor Award. The smaller scale of the aluminum-sulfur batteries would also make them practical for uses such as electric vehicle charging stations, Sadoway says. He points out that when electric vehicles become common enough on the roads that several cars want to charge up at once, as happens today with gasoline fuel pumps, "if you try to do that with batteries and you want rapid charging, the amperages are just so high that we don't have that amount of amperage in the line that feeds the facility." So having a battery system such as this to store power and then release it quickly when needed could eliminate the need for installing expensive new power lines to serve these chargers.
"The first order of business for the company is to demonstrate that it works at scale," Sadoway says, and then subject it to a series of stress tests, including running through hundreds of charging cycles.

If you're looking for a detailed breakdown of how this new battery works, we recommend you check out Ars Technica's article here.
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New Aluminum-Sulfur Battery Tech Offers Full Charging In Under a Minute

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  • Important questions (Score:5, Interesting)

    by backslashdot ( 95548 ) on Wednesday August 24, 2022 @10:09PM (#62820467)

    1. Watts per volume?
    2. Watts per weight?
    3. Degradation over 1000 cycles?

    • by Angry Coward ( 6165972 ) on Wednesday August 24, 2022 @10:29PM (#62820519)
      You forgot 4. power out/power in. All that heat is coming from inefficiency in charge/discharge.
      • You forgot 5: can they actually manufacture the thing at scale? There are all kinds of really nice battery techs out there, but none of them ever see mass adoption because they're missing that, and only that.

        • There is #6: Safety. Ideally, thermal runaway protection, and general high idiot resistance.

    • by Thorfinn.au ( 1140205 ) on Wednesday August 24, 2022 @10:33PM (#62820539)
      Most of these are answered in paper and the Ars Technica article
      Operating temperature 110 C, so quite do-able for a stationary power source and very small overhead with good insulation
      After 500 cycles battery capacity is over 80% of initial spec
      Energy capacity similar to Li-ion
      and don't mix with water -> H2S (poison and flammable) noted now so can be part of good design

      Lots of opportunity for use, as a storage as part of wind and large scale solar panel farm
      • by aaarrrgggh ( 9205 ) on Wednesday August 24, 2022 @10:49PM (#62820585)

        OT: Johnny was a chemist; he isn't any more, for what he thought was H20 was H2SO4.

      • by Anonymous Coward

        Where does the energy come from to keep the battery at that temperature?

        Massive heat plus flammable poisonous fumes. Great idea! What happens when one of these cracks open in a vehicle crash or in your flashlight?

        Keep working my dude, you haven't solved anything yet (FYI this particular researcher has made like a hundred different battery chemistries in the past, all failures in the market).

        • by MacMann ( 7518492 ) on Thursday August 25, 2022 @03:26AM (#62821057)

          Where does the energy come from to keep the battery at that temperature?

          From the electrical grid of course.

          Massive heat plus flammable poisonous fumes. Great idea! What happens when one of these cracks open in a vehicle crash or in your flashlight?

          These batteries are not for the vehicles, they are for the vehicle chargers. The headline is misleading. I caught on to this because I've heard of this professor Sadoway before and thought in no way these batteries are practical for vehicles. It's easy to miss but in the article the proposal is to have these batteries at the EV chargers to better manage the power draw from the grid. The "fully charge in under a minute" is from having a big battery at the charging station able to dump power into the EV batteries without overloading the grid. The batteries at the charging station can then use the time between cars stopping to charge to "trickle charge" the big massive batteries at the station.

          Keep working my dude, you haven't solved anything yet (FYI this particular researcher has made like a hundred different battery chemistries in the past, all failures in the market).

          Yep. Professor Sadoway has been at this for at least 10 years.

          Sadoway has tried all kinds of chemical reactions to make this economical for someone to build. It's still cheaper to overbuild wind and solar power then "curtail" (a fancy word for "waste") the excess than build batteries to preserve that energy for later. If we do get big cheap batteries for grid storage then that makes wind and solar less attractive. Wind and solar power aren't competing with fossil fuels, everyone is already convinced that fossil fuels are bad. Wind and solar are competing with nuclear power. The problem with nuclear power is that any time they "curtail" output that costs a lot of money. Put cheap storage on the grid and they don't have to worry about waste... I mean curtailment, of that output nearly as much. That changes the math on operating costs.

          The headline is very misleading. This technology has very little to do with EV charging, but then if the headline were not so misleading then fewer people would click to read more.

          • That's what I thought when I first saw the battery spec. This would probably be good for the convenience store / charging station of the future. Along with cars that can charge in about better than 80% in less than 6 minutes (at nearly 1MW: https://insideevs.com/news/541... [insideevs.com] ) it would be a good foundation for electric vehicles taking over from fossil fuel vehicles.

            One step at a time.
        • by jwdb ( 526327 )

          Where does the energy come from to keep the battery at that temperature?

          It's in the fucking summary.

          What's more, the battery requires no external heat source to maintain its operating temperature. The heat is naturally produced electrochemically by the charging and discharging of the battery.

          Keep working at writing comments, dude. Eventually you'll get it.

      • by AmiMoJo ( 196126 )

        Sounds a lot like sodium sulphur batteries, which have been used for grid scale storage for quite a while now, only lower temperature and less corrosive. 500 cycles is half that of a typical sodium sulphur battery, but if it isn't corrosive it might more than make up for that.

    • by Arethan ( 223197 )

      I think you wanted watt/hr instead of just watts, but yes, these are the typical battery tradeoffs.
      You're almost always sacrificing weight, volume, capacity, discharge rate, and/or lifespan, in order to meet some optimistic magic-quadrant criteria that the sales goons swear is why their sales funnels aren't reaching completion. Quite often, you'll end up sacrificing several useful properties in order to meet just one criteria -- that's just how battery chemistry always seems to work out.

      What I find more int

      • by XXongo ( 3986865 ) on Wednesday August 24, 2022 @11:33PM (#62820683) Homepage
        These are actually pretty low temperatures, compared to the previous generation of molten-salt batteries, the Zebra battery; and way low compared to the generation before that, the Na-S batteries.

        The usefulness of high operating-temperature batteries depends on application. For baseload power load-leveling, no problem. Heat leak goes as the surface to volume ratio, so for huge applications, the heat loss is insignificant. For cars, no. You'd have to heat the batteries up before they start producing power. Nobody wants a car where you have to warm it up for ten minutes before you can drive.

        (the article handwaves right over that point. It says that the batteries self-head, but no, only when charging or discharging... but most of the time a battery is just sitting there, and want a battery to be able to hold charge when it's neither charging nor discharging.)

        For cell phones and laptops, hell no.

      • I think you wanted watt/hr instead of just watts

        No. Watts per hour has no physical meaning - watt-hours (watts times hours) is a unit of energy that are often used for batteries so that would be useful. However, you also want watts as well since it is not enough for a battery to just store energy it also has to be able to provide it with a reasonable rate which is what watts, as a unit of power, measure: energy per unit time.

        • Re: (Score:2, Informative)

          Watts per hour has no physical meaning
          It has.
          I suggest to check your power bill.

          • Electric bill is not watts/hour. Its watt-hours. As in watts times hours. Kwh. There is a distinction. Watts does not account for time, its a measurement of consumption at a particular slice of time. A watt is a unit of power which in physics is an energy times distance. Like a joule, which is a newton*meter.
            • You are right, I misread his comment.

            • by nasch ( 598556 )

              Power is energy over time, not energy times distance.

              https://en.wikipedia.org/wiki/... [wikipedia.org]

              • by e3m4n ( 947977 )
                wrong... a Joule is a Newton-Meter, An Erg is a Dyne-Centimeter. i realize physics sucks for you. One joule equals the work done (or energy expended) by a force of one newton (N) acting over a distance of one meter (m). And a Newton is kg * m / second-squared. Or essentially mass times acceleration. That makes a Joule m^2 * kg / sec^2. What you should have said is ENERGY is a function of time (specifically acceleration) .
                • wrong... a Joule is a Newton-Meter

                  What you meant to say is _force_ times distance. What you actually said was _energy_ times distance.

                  • by e3m4n ( 947977 )
                    what i elaborated was 1 Joule was a meter-squared times 1 kilogram divided by seconds-squared. Watts is not a measurement over time. My power supply draws 40Watts, thats not a value of consumption. Its a RATE at which it is drawing power, that very second. Watt-Hours is a measurement of total consumption. Which is why watts/sec is not an actual thing (the point of the thread someone started) Watts are Joules/sec. So a wat per second would be a joule/sec/sec? and since a joule is m^2*kg/sec^2, you would
                    • Which is why watts/sec is not an actual thing (the point of the thread someone started)

                      Yes - I get that because I was the person who started this thread! ;-) However, what you said was that:

                      A watt is a unit of power which in physics is an energy times distance.

                      and this is not correct. If you mean mechanical power then it's force times velocity and if you meant energy then it's force times distance but there is no way that you can get energy times distance to give you a power - it's dimensionally wrong. I'd also be a bit careful about newton-metres. While you are correct that a joule is technically a newton-metre, the units of newton-metres (Nm) are used to mea

                    • That's right. The difference between energy (joules) and torque (newton metre) is not apparent in dimensional analysis in terms of SI units. Both are kg m^2 s^-2.

                      However, the difference is apparent if you look at the vector/tensor types.

                      Loosely speaking, energy (J joule) is a scalar derived from dot product of force (N newton) with displacement (m metre). It requires a single real number to represent.

                      Torque is a vector derived from cross product of force with displacement. It requires three real numbers

                    • Careful: those are not the definitions generally used in physics. Co- and contra-variant are used for vectors and tensors in relativity and we refer to a moment - or moment of a force - (not a torque unless you are an engineer) as either an axial vector or a pseudo-vector [wikipedia.org].

                      Moments also only transform differently to vectors for specific transformations, not in general. Two of the common ones are parity and lorentz transforms. However, under a translation or rotation transform it will behave exactly like a
                    • Yep. I'm aware of that but thanks for your good explanation for others. I gave at least four names for the type of the torque or moment of force, as type (1,0) tensor, covariant vector, convector or one-form, and the naming I gave is from tensors and differential forms. I didn't include the others because I thought the explanation would be confusing. Pseudo vector and axial vector are also used in physics and are a bit more "engineering", similar to torque vs moment of force. In a thread where others are s
                • by nasch ( 598556 )

                  Hey, if you disagree with the wikipedia article then go edit it. But don't forget to cite your primary source(s).

                  "In physics, power is the amount of energy transferred or converted per unit time."

                  • by e3m4n ( 947977 )
                    you just contradicted yourself. energy PER unit time is not the same thing as energy OVER time. Thats the exact opposite. Break them all down to their base units. Distance is a factor because without distance you have no force. Without force you have no work (energy). A Watt is a Joule PER second, not a Joule over the course of 30 seconds. A Watt does not tell you how much you consumed (that requires knowing the time). It tells you the flowrate of your energy. You have to multiply that by time to get your k
                    • by nasch ( 598556 )

                      "Over" in the mathematical sense; divided by; energy / time.

                    • by e3m4n ( 947977 )
                      in that case then we are saying the same thing. distance is, however, one of those embedded core units.
                    • by nasch ( 598556 )

                      So you agree this was an incorrect statement? "A watt is a unit of power which in physics is an energy times distance."

                    • I think we are all saying the same things different ways. Unfortunately, OVER is used both for multiplication-like (integral, summation) operation and division-like (fraction, derivative) operations.

                      Total energy is instantaneous power INTEGRATED OVER time: E = integral(P dT)

                      For constant power, total energy is power TRANSFERRED OVER (multiplied by) time: E = P * deltaT

                      Average power is energy OVER (fraction, divided by) time: P = E / deltaT

                      Instantaneous power is the time derivative of energy, i.e. dif

          • I don't know what US power bills are like, but mine in the UK show the number of kilowatt-hours (also called "units") that I've used. That's a unit of energy, equal to 3.6 megajoules, so makes sense that it's on the bill.
            Watts are a unit of power, the rate that I'm using energy - and the same thing as joules per second.
            Watts per hour is a rate of change of power, the rate of change of the rate I'm using energy - and equivalent to 3600 joules per second per second.
            Might be useful in some cases - "Energy use

          • Nope. Power usage on a power bill is measured in watt-hours (W.h) or kilowatt-hours (kW.h). A kilowatt-hour is a measure of energy (like joule or calorie) and is equivalent to 3.6 MJ (3.6 million joules). Measuring quantities in watt per hour (W/h) is not physically meaningful, apart from highky isoteric situations such as measuring how quickly power capacity is being added to a country (eg âoeCountry X added on average 5 gigawatts per year of power generation capability over the last decadeâ).
          • Watts/hr is just Joules.

            • No.

              Even ignoring the constant (hour is 3600 seconds), watt/hour is NOT joules (or energy).

              Your subject line is meaningless.

              W/h (watt PER hour) = (power per time) = ((energy per time) per time) = (E/t)/t = (J/s)/s.

              It is a rate of change of power, meaningless in most contexts.

              The correct alternative unit for energy is (power TIMES time) = (watt*hour) = (joule per second)*(3600 seconds) = (3.6 million joules) = (energy).

              Energy is NOT (power PER time), with a division.

              Energy is (power TIMES time)

      • Those aren't searing hot AAs that you're going to brand your skin with by picking them up, they are talking about industrial equipment that would be buried underground at a refueling station, or otherwise be made difficult to access. Besides which, we have these things called refractory bricks and insulation...

    • by tcgroat ( 666085 )

      Per the Ars Technica article:

      " If the cell was discharged over two hours and charged in just six minutes, it still had a charge capacity per weight that was 25 percent higher than lithium-ion batteries and retained roughly 80 percent of that capacity after 500 cycles—well beyond what you'd see with most lithium chemistries."

      The follow-up question is how much the capacity loss accelerates past the 80% point (and whether the failure rate does the same). 500 cycles is only about five years of twice-wee

      • by nasch ( 598556 )

        for an EV application this would be about the time you make the last payment of the purchase contract.

        This isn't intended for EVs. Not that that means the charge cycle question is not important, but it's different.

    • #7 if it becomes fully discharged, is it bricked?

    • 1 minute to charge a 100 KWH battery is shall we say "dramatic"? 480 volt three phase for a 10 minute fill up is about 420 amperes per leg. (0.6 megawatts for ten minutes.) A real 1 minute fill up would require about 4200 amperes per leg. That's not your standard wall socket to say the least. I bet the surges when charging turns on and off will be dramatic - a localized EMP event?

      {o.o}

    • by raynet ( 51803 ) on Thursday August 25, 2022 @06:33AM (#62821369) Homepage

      0. Is this patented and developed by single company?

      Usually these new breakthrough batteries are and those companies die after couple years after running out of funds before they can bring the product to the market and compete with mass produced LiFePO4 etc batteries.

      It would be so much smarter to develop these new batteries with multiple companies and just request tiny royalty, couple cents per battery at most. Inventors would make money for years and product would be on the market. Everybody would win. But all these inventors seem to think they can do it all, get billions etc. And almost always fail to bring the product to the market.

    • Energy density is certainly a good question. Building something to protect yourself against 100C would also be a concern. On the upside, it will offset your heating bill in the winter.
    • 1 and 2 are not relevant for the applications. I.e. for a charging station, the batteries can easily be a few tons and kubic meters. The same goes for home batteries. A lot of people have the space to put a few big and heavy low energy density batteries. I think the problem is keeping the electrolyte liquid. It sounds like charging and/or discharging fast is a necessity to keep it at temperature.
    • Watts per volume doesn't really matter for a stationary application, and really watts per weight doesn't matter either.

      Charge cycles are all-important. 365 charge-discharge cycles per year, and therefore 3650 (plus a couple more for leap years) in ten years.

      Ability to recycle the materials is rather important too.

  • If a 50 kW battery is charged in a minute with 12(probably 13.4) volts, that has to be close to the definition of danger I have heard in a long time.
    • Didn't some sci-fi novel have the line "the meter-thick bus bars cleared their grisly short"?
      • by suutar ( 1860506 )

        I seem to remember that line so I'm going with yes. One of Doc Smith's? Maybe Spacehounds of IPC?

    • I missed if the article talked about limiting discharge. Charging fast is cool. Discharging fast is dangerous! Bump into your battery and it explodes, catches fire, and can't be put out!

      • by MacMann ( 7518492 ) on Thursday August 25, 2022 @02:42AM (#62821005)

        These aluminum-sulfur batteries are for managing the power surges at the grid side of the vehicle charging, not the vehicle side. This is a new chemistry for the large grid storage batteries so we aren't using valuable lithium ion batteries for grid storage. This means more lithium is available for making cars instead of big batteries out in Australian deserts.

        Keep the batteries on a big concrete pad in the middle of nowhere and there's nobody going to bump into them. If by chance something or someone does bump into them and they start on fire then just let the thing burn, the thing would a total loss anyway if doused in water so save the water and just keep people from getting too close to the fumes and heat. Once it burns out then pour a new slab over the aluminum oxide ash and start over. Aluminum oxide is a major component of sand, it is the "sand" in "sandpaper", so not any real environmental hazard to just bury in place.

        • by Anonymous Coward

          Aluminum oxide is a major component of sand

          It's a major component in sand used as abrasives, but that's almost all synthetic - most natural sand is primarily silicon dioxide. If everyday sand were aluminum oxide, it'd be cheaper just to use that than processing bauxite to extract aluminum, since conversion to Al2O3 is the first step in refining bauxite into metallic aluminum.

    • Such battery packs will need some hefty connectors.

  • If I had a dollar for every slashdot revolutionary battery tech article that's ever been published, which never made it to mass production I'd probably be able to retire.

    • Don't be so cynical. I'm sure practical applications of this technology are only 10-15 years away! Just like fusion!

      • Forget fusion, where are the flying cars?
        • I miss the days when all this futuristic stuff would be commonplace "by the year 2000". We need to set a new a new future date that is within most people's lifetimes but is far enough away that we don't yet have to worry about all the fine detail of actually achieving it. I'd like to propose 2050. Musk will likely be a cyborg by then with his brain implant, so with his supercharged intelligence, will be able to fix all that tricky self driving stuff, the mars base, etc etc...
    • It's an article about an interesting new result in academic research on batteries. I'm not sure what you're expecting. Perhaps stick to reading news sites that only talk about new commercial products?
  • by MacMann ( 7518492 ) on Thursday August 25, 2022 @01:28AM (#62820927)

    In the fine article there is mention of using this technology for charging BEVs, but careful reading tells us this battery technology is not for the batteries in the BEVs. This is battery technology for the BEV chargers, not for inside the BEVs. This may solve the cost issue in batteries in stationary applications but not that of voltage and current needed to put energy into BEV batteries.

    I recognized the name Sadoway in the summary. The name Sadoway comes up often in discussions of new battery chemistry because this man is obsessed with lowering the costs of batteries by using cheaper materials. This is admirable but do we need to print up new news articles every time this man offers a new combination of periodic elements as anode and cathode? This is another variation on a theme in his molten metal battery idea. He keeps trying different variations on his theme, and at some point he's going to run out of elements on the periodic table to try.

    Because the batteries use molten metals they are not suited to use in vehicles. If the batteries get cracked open in a crash then this would create a hot burning mess that could vaporize human flesh on contact. We already have toxic flaming messes in vehicle crashes, and these batteries would be worse. If the alternative isn't safer and cheaper than what we already have then it's not going to sell well among the public, and won't get approval from the safety regulators. I know liquid hydrocarbons can make a toxic flaming mess in a crash, it's just that batteries containing molten metals are worse.

    The batteries rely on layers of materials kept separate by gravity, the layers make up the battery float on top of each other. If put under vibrations like that seen in nearly every vehicle in motion then they won't maintain the layering needed for operation. Sadoway knows his batteries are not suited for use in vehicles, but the people writing the news articles need to make this sound like something useful for electric vehicles in some way or it's not going to get the needed advertising clicks.

    The biggest problem with electric vehicles is not in the battery chemistry. If we solve that we'd still be left with the problem of the high voltage and current required to move energy anything close to that of pumping liquid hydrocarbons into a tank. Even if we account for electric motors being far more efficient than internal combustion engines there's still a big problem with the amount of power transferred by electrical conductors of a size we'd consider reasonable for charging electric vehicles. People need to just look up the math on this. Copper conductors in air would be quite large. If we use active cooling to make the conductors smaller then we'd have to consider the size and weight of the cooling systems.

    Battery chemistry is a problem for electric vehicles. It's not the only problem. There's still energy needed to make up for rolling resistance, air resistance, and so on. Any resolution to these problems can be applied to vehicles with internal combustion engines. Any improvements in energy losses in getting vehicles to move widens the gap that BEVs need to cross to compete with ICEVs.

    • People need to just look up the math on this. Copper conductors in air would be quite large. If we use active cooling to make the conductors smaller then we'd have to consider the size and weight of the cooling systems.

      I've worked with some companies on this. Interestingly there are already designs floating around and being tested for watercooled charging cables. The size and weight isn't an issue as the majority of the weight is fixed within the charger. The biggest issues that are being run into are:
      - Wear and tear on the cable (water and electricity are not a good combination).
      - Connector heating up (change in connector so that water can circulate around the connection point is impractical)
      - Wiring within the vehicle c

      • Perhaps the charger can contain enough cryo to make superconductors work or use some other kind of coupling (inductive perhaps). After all, complexity and weight in the charger is less of a problem than in the car.

        I'm surprised that the problem is getting electricity across the threshold between charger and car and not distributing it within the car.

        Maybe it's time to put multiple charging connectors on the car

  • We hear about all these new technologies over the years (Pogue cutting a battery with scissors and it doesn't explode..) YET we're STILL using LiION..
  • But i want to know where my Flying Car is. I don't mind if it's electric. I just want it before I die.

    • People are bad enough at driving in two dimensions. We don't need every Tom, Dick an Harriet distracted flying over cities and towns.

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