Aluminium Air: The battery that just won't die  xD - Page 1
Forum section: electronics / general

author: AVGresponding
author_rank: Super Contributor
timestamp: November 08, 2019, 01:04:56 pm
content: Thunderf00t already busted these ofc, but they just keep on reporting on it...

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 08, 2019, 02:49:56 pm
content: Don't have time to watch this at the moment. Just a thought about the topic: metal-air batteries in general, and Al-air ones in particular, are not dodgy tech per se in the least.One of the most used variant, the zinc-air battery, is ubiquitous (used, for instance, in hearing aids). The energy density is amazing. One of the downsides of this battery type is the (pretty) limited shelf life.AFAIK, Al-air batteries have been expored in military applications. They pose unique challenges though, so seeing them as a direct replacement for Li-ion batteries at the moment is more than a stretch, we're just not there yet and still far from it.https://www.sciencedirect.com/science/article/pii/S246802571730081XAgain I'm not commenting on the video itself, and the "just won't die" part makes no sense whatsoever, it's just marketing bullshit.But metal-air batteries are definitely interesting.

author: AVGresponding
author_rank: Super Contributor
timestamp: November 08, 2019, 04:27:59 pm
content: Indeed, but not for electric cars.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 08, 2019, 04:47:41 pm
content: So the idea is that you 1) extract bauxite, 2) process it with lots of energy to get aluminium, and then in the car 3) basically reverse the process to recover the energy you put in 2)? How is that better than a li-ion batt that can be recharged in place, no need to remove/dismantle/replace anything?

author: Marco
author_rank: Super Contributor
timestamp: November 08, 2019, 05:18:48 pm
content: Quote from: ThickPhilM on November 08, 2019, 04:27:59 pmWell it's not a car which charges off electricity, so by most people's definition it's not an electric car to begin with.Mechanically recharging aluminium or zinc batteries are a potentially interesting alternative to fuel cells though. Hydrogen is difficult to store, ammonia is too bloody dangerous in high quantities and everything else which can power a fuel cell is for the moment not cost effective to generate with renewable energy. Lousy round trip efficiency, but so does hydrogen ... and there are still large investments being made in hydrogen.Mechanical recharging can be done at a couple of orders of magnitude faster rate than electrical charging of a secondary battery. Also the energy density is higher.

author: AVGresponding
author_rank: Super Contributor
timestamp: November 08, 2019, 06:39:33 pm
content: It's not imaginary technology, it's just impractical technology.It's just mathematics. You need to watchThunderf00t'svideo, he explains the maths better than I ever could.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 08, 2019, 06:40:16 pm
content: Quote from: Marco on November 08, 2019, 05:18:48 pmDitto.Yes it's an interesting alternative, and yes it has already been studied seriously, it's not just a gimmick.As you said, the idea is not to make these batteries electrically rechargeable (which would give no real benefit here, except maybe for the energy density, which is much higher in metal-air batteries), but to replace the anodes. Knowing that aluminum is abundant. The key is also that the "consumed" anodes could be relatively easily recycled.Recharging batteries electrically (to reverse a chemical reaction) is not very efficient and is relatively slow. Any alternative to this is interesting.One of the hurdles to overcome is the rapid oxidation of the anodes in any metal-air battery. Still a lot of work to be done to make this an option for electric vehicles (as I said earlier, it has been done in military vehicles for restricted uses), but this is definitely something to keep an eye on.For those interested, read the articles I linked to (and you'll find MANY others) before forming any uninformed opinion.

author: AVGresponding
author_rank: Super Contributor
timestamp: November 08, 2019, 08:58:45 pm
content: Ok, I scanned through the information in the link you provided, and several things stand out.Firstly, this is still very much at the theoretical and experimental stage; they are still experimenting with different materials and aren't even remotely close to any kind of commercial product.Secondly, there is no mention of practical engineering issues like mass/volume increase when adding oxygen to aluminium in the kind of quantities that would make a practical vehicle electrical storage cell.Thirdly, there's no mention of any kind of recharging method, let alone one that would be safe and practical in the implied applications; indeed the only mention of even a rechargeable version of this technology is using highly exotic materials which are difficult to produce. Most of the technologies mentioned appear to be for primary cells, which are ridiculously inefficient compared to rechargeable ones.Lastly, the whole article opens with a patently disingenuous statement that the energy density of Al - air is far superior to Li -ion, while the table further down the page clearly shows that comparable (ie Li - air) Li technology would have an energy density more than 50% greater than Al - air.Smells like someone trying to justify their research budget to me.NB: If you're going to use an article to support your argument, it's a good idea to ensure that it actually does do so beforehand.

author: Ben321
author_rank: Frequent Contributor
timestamp: February 27, 2020, 04:27:10 am
content: Quote from: SiliconWizard on November 08, 2019, 02:49:56 pmWait, so metal-air batteries are NOT fake? How do they even work?

author: helius
author_rank: Super Contributor
timestamp: February 27, 2020, 06:29:27 am
content: Quote from: Ben321 on February 27, 2020, 04:27:10 amThey work through the electrolytic oxidation of metal. Seehttps://en.wikipedia.org/wiki/Zinc-air_batteryThis shouldn't be surprising, since metal can be protected from corrosion by applying voltage.(https://en.wikipedia.org/wiki/Cathodic_protection#Impressed_current_systems)So by the same reasoning, there is a (complementary) voltage produced when metal corrodes.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 27, 2020, 03:06:36 pm
content: Quote from: Ben321 on February 27, 2020, 04:27:10 amOf course they aren't, dang! If the result of Thunderf00t's video is to convey the idea that metal-air batteries don't even exist, then clearly he has failed.As helius posted above, Zinc-air batteries are the most common and well known commercial application. Have been for several decades now. I think the biggest market for them are hearing aids, and it's a very large market. The benefit is that they pack very high energy density, unmatched to this day, at least at the same cost point. Another one is that they are relatively clean - zinc is not too bad. They used to contain a small amount of mercury, but it's been banned in many countries, so now they don't. Recycling them is easy and doesn't cost too much.They are, to this day, essentially primary batteries - meaning once they are depleted, you discard them. Another downside is that their operating life is relatively limited, as they are constantly reacting with air even when you don't draw current from them, once you have started the reaction - there is an adhesive tab that closes air openings, that you need to remove before using the battery.There have been attempts at devising rechargeable versions of them (silver-zinc batteries namely). You can take a look there for instance:https://www.zpowerbattery.com/They are being used commercially but they are pretty expensive, and I'm not too sure how stable/reliable they are at this point. The process itself is IMO not very scalable (meaning it would be pretty hard and expensive to make very large batteries like this. The ones this company works on are very small.)As I said earlier, the whole idea behind potentially using metal-air batteries for other applications (such as in EVs) was to use them as primary batteries, not as rechargeable ones, and it has been studied not just by lunatics. They would essentially be "recharged" by replacing the anodes, and recycling the used ones. Of course this still poses a number of challenges to this day, and may never see the light as is, at least on a large scale for commercial applications.The approach itself - beyond the feasability - is not necessary stupid per se: we're obsessing over electrically recharging batteries, whereas there are other possible approaches to "refilling" batteries that could be just as practical and possibly more efficient (of course we can mention fuel-cell batteries using this approach, for instance.)

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 27, 2020, 03:42:27 pm
content: Quote from: ThickPhilM on November 08, 2019, 08:58:45 pmFor metal-air batteries, of course there have been commercial applications for ages (zinc-air for instance), but specifically for Al-air batteries, that's right, and I never said otherwise. Just said it was certainly an interesting topic to keep an eye on.Quote from: ThickPhilM on November 08, 2019, 08:58:45 pmMaybe not in the very limited stuff I linked to, but this was not meant as a complete SoA. I clearly said it was just a start and that you could further look up many other references on the subject. Sorry about that, but I don't think Thunderf00t has made anything close to a decent SoA either here.But I have definitely seen this kind of issues discussed in other papers.Quote from: ThickPhilM on November 08, 2019, 08:58:45 pmThere isn't, and this is exactly what I said earlier. The whole idea behind potentially using Al-air batteries from everything I've seen, is to indeed use them as "refillable" primary batteries. You'd basically get to a station equivalent to a gas station and replace the anode(s). The used ones would get recycled. Whether this would be inefficient on a large scale depends on many factors, but it's not as ridiculous as it may look if we can find efficient ways of recycling the anodes. Compare the cost of producing electricity, distributing it, the efficiency of chargers, the cost of extracting Lithium and Cobalt, the cost of producing Li-ion batteries, the cost of recycling them when they are dead, etc. What's going to be more expensive in the end? It's not necessarily as clear cut as it seems.As I said, I think that should be seen as something similar to fuel cells, with similar benefits and constraints.OTOH, any organization/company claiming electrically rechargeable Al-air batteries would just be a scam indeed, and any that would claim anything close to being ready to get to the market, even more so. That we can fully agree on.Quote from: ThickPhilM on November 08, 2019, 08:58:45 pmSo? Are you sure you got the idea? Yes the energy density is far superior to Li-ion, which is currently the SoA kind of batteries used in EVs. Other metal-air batteries may pack even more energy density than Al-air, but have you considered the point? Al is one of the most common metals on Earth, far more pervasive and cheaper than Lithium. Li-air batteries would definitely be completely unpractical here, because again the whole idea is to be able to replace the anodes and easily recycle them. So the above comment missed the point completely IMO.That it's currently not ready for commercial applications is obvious, that it may never see the light is probable too. But that it's a completely stupid approach not even worth considering, I don't quite agree here, and that was my point. And as I said in the previous post, if on top of that it conveys the idea that metal-air batteries don't even work, that's completely silly, and that would be where I think some Thunderf00t's videos, even though he does a good job overall, are overly clickbaity and misleading for the less informed viewers.I again never claimed it was anywhere near ready for any commercial application. Would it even be worth funding a startup for this at this point? Not at all, would be ridiculous indeed. But is funding (reasonably) some research on metal-air batteries in general worth it? I think so.And as I said earlier, the title "The battery that just won't die", is completely silly.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 27, 2020, 06:48:12 pm
content: Quote from: SiliconWizard on February 27, 2020, 03:42:27 pmI based it on the ridiculous claims in the video.I'm well aware that metal-air cells work, I just think they seem an impractical proposal for electric vehicles.Transporting what would be hundreds of thousands of tonnes of electrodes around is a lot less appealing than fast-charge technology for secondary cells.

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2020, 01:11:35 am
content: Quote from: GeorgeOfTheJungle on November 08, 2019, 04:47:41 pmAluminum-air currently has about 6 times the energy density of lithium-ion so for the same battery weight, the car would have 6 times the range. Is there a market for an electric vehicle where the battery only has to be replaced once or twice a month instead of being charged every day?

author: Cyberdragon
author_rank: Super Contributor
timestamp: February 28, 2020, 08:29:29 am
content: Quote from: David Hess on February 28, 2020, 01:11:35 amThat assumes the same size battery, have you seen the size of EV batteries? How would you make that easily replaceable? Would the owner be responsible for changing the whole thing or would you have to take it to a mechanic?

author: hendorog
author_rank: Super Contributor
timestamp: February 28, 2020, 09:12:28 am
content: Quote from: Cyberdragon on February 28, 2020, 08:29:29 amThe same car will have a much lighter battery. Using the above figure Al-Air would be 6x lighter than Li-ion for the same range.Or, taking the range of a Tesla S as 390 miles, then the Al-Air as 6x more energy then the range is about 3700 km's.Then, maybe you don't replace the whole thing, instead you replace 1/10th of it every 370 km's on average.Or, you could choose to replace 2/10 ths after 740 kms. Or just wait a bit longer.Plenty of options.

author: OwO
author_rank: Super Contributor
timestamp: February 28, 2020, 12:42:59 pm
content: Seems like it would be useful in RC airplanes if it is cheap enough.

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2020, 08:51:32 pm
content: Quote from: Cyberdragon on February 28, 2020, 08:29:29 amI imagine something like a cherry picker to lift the old battery out from under the hood and place the new one. It could even be done with a fork lift.There have been proposals to do this with the battery mounted under the car using a service pit but I think hood access would be more universal.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 29, 2020, 01:38:13 am
content: Quote from: Ben321 on February 27, 2020, 04:27:10 amI guess when you've known a few deaf people you get used to seeing those little trays with the batteries. You peel off the sticker to open the vents and it starts working.

author: David Hess
author_rank: Super Contributor
timestamp: March 02, 2020, 09:16:31 pm
content: Quote from: Alex Eisenhut on February 29, 2020, 01:38:13 amAnd they make big ones for applications where long standby life and high energy density are important like emergency gear.https://en.wikipedia.org/wiki/Zinc%E2%80%93air_batteryhttps://www.cegasa.com/en/ez8