14 ms·
Hybrid supercapacitor offers NiMH energy density, charges much faster
- choeger 6y agoJust reading the headline, seeing no mention of cost, size, and durability. So it is lightweight, extremely bulky, made out of fairy tears, costs a gazillion €, and breaks after the second charge?
- wffurr 6y agoThe article, which is not paywalled and is a fast read, also doesn't mention cost. The energy and power density is closely correlated to physical size, so that's covered. The article does mention durability, but only in the context of the lab's testbench: "The QUT team is pleased to note that these hybrid supercaps also last about twice as long as lithium batteries on the test bench, retaining 90 percent of their initial storage capacity after 10,000 full charge/discharge cycles." The article keeps mentioning "lithium batteries" which I presume refers to LiIon/LiPo/LiFePO rechargeable batteries and not disposable Lithium batteries, but it's not certain. Overall it's not a great article. Mostly a fluff PR piece for Queensland University's lab. I'd still plead with you to read before commenting, especially something snarky and dismissive.
- bitwize 6y agoDo they explode if you look at them funny?
- tyingq 6y agoSci-Hub link to the paper: https://sci-hub.se/https://doi.org/10.1002/adma.202004560 https://sci-hub.se/https://doi.org/10.1002/adma.202004560
- magicalhippo 6y agoFWIW the paper is open access: https://onlinelibrary.wiley.com/doi/10.1002/adma.202004560 https://onlinelibrary.wiley.com/doi/10.1002/adma.202004560
- desireco42 6y agoThis is fantastic discovery, I don't want to take anything from it. If you would have your car battery in such form, in case of accident, there would be potential that all this static energy gets released at once, which wouldn't be pretty. Again, really good discovery, even if capacity is not on par with current batteries, making it practical would allow for more reusable energy storage.
- EricE 6y agoNot sure why people are down voting you - unlike chemical energy storage solutions capacitors can indeed dump all their energy at once. The literal definition of an explosion. Not saying it should preclude them from use; indeed I think super capacitors are the only thing that will make electric cars acceptable. Just saying that it’s something that needs to be addressed as part of their design. Huge amounts of energy that have the potential to be released instantaneously should ALWAYS be respected/considered and not glossed over, especially for something intended to be deployed widely in vehicles where accidents/physical destruction does happen.
- BenjiWiebe 6y agoLarger capacitors tend to have much higher output resistance. They can dump their power quickly, but not nearly as fast as a tiny capacitor.
- desireco42 6y agoIt is a HN thing, people don't want to hear anything that isn't agreeable :). You said everything and I am sure they will come up with some technological way how handle discharge in case of accident, in case capacitor batteries become a thing.
- deleted 6y ago[deleted]
- Cthulhu_ 6y ago> [...] research [...] the QUT team describes a design Yeah ok cool, join the giant pile of revolutionary battery designs and remind me when it's a physical product, tested, verified and ready for mass production.
- protoster 6y agoAbsolutely agree, it feels like I'm reading about revolutionary battery tech on a weekly basis, with no actual products in sight.
- DennisP 6y agoNobody's impressed unless someone triples battery density overnight with a radical new chemistry, but lithium-ion energy density has tripled since 2010. https://cleantechnica.com/2020/02/19/bloombergnef-lithium-ion-battery-cell-densities-have-almost-tripled-since-2010/ https://cleantechnica.com/2020/02/19/bloombergnef-lithium-io... There's a long road between the lab and production, but having all this cool stuff in the lab suggests that the long-term trend can continue for a good while.
- LegitShady 6y agoHow come aa batteries are still 2000-2500 mah still?
- JulianMorrison 6y agoThey won't be being made with the latest tech, since consumers aren't too battery life sensitive and changing up the production lines costs.
- StillBored 6y agoWell there are: https://data.energizer.com/pdfs/l91.pdf https://data.energizer.com/pdfs/l91.pdf But the problem isn't just capacity its maintaining the traditional zinc-carbon voltage profile. There were a bunch of much higher capacity Li/AA batteries from various manufactures that used buck converters inside the "cell" but they have fairly short lifespans, and efficiency loss due to the electronics. For a lot of cases, companies just abandoned the AA form factor and embedded a rechargeable battery.
- tsmarsh 6y agoAs a turbo for cars to enable focusing on super high wH/kg storage class batteries this is interesting. But as power delivery for drones and rail guns these could be game changing.
- LeonM 6y agoCurrent battery tech can already deliver enough charge/discharge current to act as a momentary power boost for combustion engines. Many hybrid systems act this way, providing additional acceleration and/or torque filling (i.e. delivering power in between gear-shifts of the ICE). Maybe you could recoup a bit of additional power during hard braking with supercapacitors, but in practice I doubt it's going to make a meaningful difference. For drones I don't understand why supercapacitors with equal energy density would be beneficial? I don't own a drone, but is charge time an issue?
- maxerickson 6y agoIf you can charge a capacitor, your storage battery doesn't have to be designed to meet peak power requirements, rather, average+capacitor charge. Whether it makes much of a difference who knows, but it may open up different chemistries or whatever.
- JulianMorrison 6y agoDrones probably care more about the output rate than the input rate? If you need a fast recharge you can change out the battery, so that has to be less of an issue. With high output, the drone can go fast, change course in a hurry, carry a lot of weight, or fly into a headwind.
- Tade0 6y ago73 Wh/kg is a decent number. IIRC the previous gen Prius had 46Wh/kg batteries. Perhaps with some reconfiguration it would be possible in the future to give those old machines some additional oomph, as the discharge limit in their NiMH battery packs is way below the combined power of the two motor-generators(21kW vs 60kW).
- hinkley 6y agoFor comparison, Maxwell has supercaps with a power density of 5.9 Wh/kg. But it's also rated at half a million charge cycles.
- numpad0 6y agoI wonder why no one is talking about acceleration limiters implemented in pedals and inverters in non-Tesla cars. The reason why only Tesla is famous for its instant torque is because only theirs don’t have it.
- Tade0 6y agoMy Toyota hybrid has instant torque - just not a lot of it. It's only really noticeable in the "power" (I guess calling it "sport" would be too much) setting.
- numpad0 6y agoI was thinking about a potato video I no longer have links to, that explained how shifting from N to D or B(not sure which) while flooring accelerator bypasses an undocumented safety limiter and cause the car to jump forward harder than the car normally would. Nissan Leaf reportedly has a similar jerk limiter feature. Isn’t it a bit odd that no one talks about it? Though probably the fact is just that no one take stock Prius or Leaf seriously
- Tade0 6y agoI think it may be from R to D - I do that a lot and you're almost guaranteed to get all the torque you want this way - at least I always had, as opposed to just accelerating from a standstill, to which sometimes the ECU would react with a cold "yeah, no". I read that in the former case it's connected with the fact that the motor-generator attached to the sun gear has to start turning in the opposite direction to assist acceleration - the high-pitched whine of the inverter appears to support this theory. As for talking about it: I guess people just assume all EVs have instant torque. I for one was surprised to learn that the Renault Zoe has a delay put there supposedly to emulate an automatic transmission. The IONIQ hybrid on the other hand, which I've test driven, has to react like a regular automatic because the electric motor is sandwiched between the engine and the transmission. I was meaning to get it after my first Toyota hybrid got stolen, but the way it reacted to throttle input turned out to be a deal breaker for me.
- sigmaprimus 6y ago>>They will be excellent for quick-response power-smoothing and peak load management in industrial settings. I know they are talking about feed back from very large multi-phase motors but... I wonder if they could leverage the power from electrical storms? Literally lightning in a bottle?
- Aardwolf 6y agoDoes it also keep its charge for long enough, like at least a few days?
- tempodox 6y agoThe use case seems quite different, but my solar watch uses a (super?)capacitor to buffer the energy delivered by the solar cells. When fully charged, it can run for more than a year in the dark (i.e, you can go beyond the polar circle without worrying that your watch will go belly-up in the middle of the polar night). Which is to say, existing capacitors are already darned good at retaining charge. I'd assume the tech described in the article has charge retention “good enough” for the intended use case.
- m463 6y agoWhat I've always wondered is - why don't we put a supercapacitor between a an EV battery and the motor? This means that EVs of all kinds, could not only get crazy acceleration, but could also recover all the energy of regen. Even battery packs with a very good layout can absorb a fraction of the acceleration energy, and less or none when the battery is cold or at the upper range of capacity. I remember reading an article about a porsche in a car magazine (many) years ago that discussed not the horsepower for acceleration but also the horsepower absorbed by the brakes to decelerate. It might have been 500 horsepower to accelerate the car, but since the brakes were very good, it could absorb 900+ horsepower when bringing it to a halt.
- linsomniac 6y agoI've been told that the Tesla Model S is the first car that had a 0-60 time that matched the 60-0. I had one of the Ludicrous models as a loaner a few years ago, and I'd believe it. I could feel the tires hunting for grip during acceleration.
- m463 6y agoBut if you look at the power-meter thing, the acceleration power is many times the regen power http://st.motortrend.ca/uploads/sites/42/2017/02/2017-Tesla-Model-S-P100D-instrument-cluster-02.jpg http://st.motortrend.ca/uploads/sites/42/2017/02/2017-Tesla-...
- linsomniac 6y agoYes, that is absolutely true, regen is only capable of a fraction of the 1,000bhp the electric motors are capable of. This is why the performance Teslas have fancy-schmancy huge ass red brake calipers.
- mikewarot 6y agoI have to believe that tire grip is the limiting factor... the maximum seems to be about 2.3 g The fastest braking from 60-0 is 16 meters (53 feet), according to https://fastestlaps.com/lists/top-quickest-stoppers-60mph https://fastestlaps.com/lists/top-quickest-stoppers-60mph Using the physics calculator at https://www.calculatorsoup.com/calculators/physics/uniformly-accelerated-motion-calculator.php https://www.calculatorsoup.com/calculators/physics/uniformly... This gives a deceleration of 22.5 m/sec^2, or about 2.3 g. I'm amazed it can go above 1 g, actually.
- sandworm101 6y agoI've always wondered about capacitors for bulk storage in cars. What happens in an accident? What happens when that capacity is bent/dented/broken? A Li battery will catch fire, the speed of that fire limited by the speed of the various chemical reactions. But a capacitor is an electrical device. The charge would move so much more quickly. Would this be more explosion than fire?
- derekp7 6y agoI've always wondered the same about a vehicle carrying around 15 - 20 gallons of highly flammable and explosive liquid fuel. What happens in an accident, where a spark in the wrong place with the correct mixture of fuel and oxygen can cause an explosion or hot burning fire? There's been a few times I've driven by a car fire, and even from the opposite side of a divided 4-lane highway, the heat I felt was impressive.
- throwaway0a5e 6y agoI'm really sick about this whattaboutism that every internet discussion about electric cars invariably devolves into at least in part. Fire requires fuel, oxygen and ignition (heat). Liquid fuels require external ignition. Batteries do not. But you also have to pump liquid fuels around and generally handle them more to make them do work. Batteries are more dangerous on a fundamental/conceptual level because they have everything they need to release their energy all at once. So we build them with hard casings for the same reason we build large safety factors into pressurized gas containers so in practice it doesn't really matter. Batteries and liquid fuels aren't really better or worse than each other from a "much safety or "won't somebody think of the children" point of view. They just require slightly different engineering considerations for an equivalent level of safety. This is directed just as much (ore maybe even more) at the parent comment as it is at you.
- derekp7 6y agoI agree with you on this, hence phrasing my comment as a reverse "what-aboutism". Handling of liquid fuels has improved quite a bit to where it typically isn't a problem. Whereas at one time you had cars (I'm thinking of a 60's Mustang) where if it got rear-ended gas from a ruptured tank could slosh into the passenger compartment. This isn't much of an issue with modern car designs. And cars have come along way in the ability to protect the occupants. That same protection measures can be applied to the battery compartment if necessary (steal roll cage, elastic restraint system, air bags). Yes, these things need to be thought about, and yes we do have agencies such as the NTSB and insurance standards that will solve the problem.
- raisedbyninjas 6y agoAnybody else resigned to scrolling by these headlines every month/week for the past five years? I just want to be notified when something is cheap, lasts, and out of the lab.
- Animats 6y agoThe actual figures are a tested energy density up to 73 Wh/kg – thus about 28 percent of what today's state of the art EV batteries offer So, no, this isn't useful for battery electric vehicles. Hybrids, maybe, for vehicles with an underpowered main engine and electric boost for acceleration. ... retaining 90 percent of their initial storage capacity after 10,000 full charge/discharge cycles. So, not a good power supply filter either. 10,000 cycles of the power line rectified to DC is under a minute and a half. There are applications for big pulsed power sources, but not that many of them. Flashguns for cameras. Aircraft carrier catapults. Nuclear weapons detonators. Railguns. Big spark generators. Most of the applications that need a huge power spike are military.
- csours 6y agoWhat about holding the charge from regenerative braking?
- m4rtink 6y agoWhat about using this for grid scale energy storage ?
- ksec 6y agoThat was my immediate reaction as well. Even on a cycle per day that is ~27 years for Grid usage while still retaining 90% of capacity. Consider weight and volume isn't a concern for Grid Scale Energy Storage I assume this is a good fit? Not to mention for something like AirPod....... no more throwing them away due to absurd Battery degradation, at the expense or lower connection time.
- nerpderp82 6y ago> So, no, this isn't useful for battery electric vehicles. This is absolutely useful for anything with a high momentary power draw. Even with the quarter of the energy density. These aren't going to supply all the energy, just the peak power. The main pack can be sized for slightly above the average power draw, and it can charge the boost pack that needs to get you up to speed or handle the surge current sink from braking. Who would use a multifarad capacitor for filtering a rectified AC line? Why is this an argument? This isn't a capacitor, it is a battery with capacitor qualities. I feel like the internet was built for arm chair generals to attempt to rain on parades.