Aluminum battery from Stanford offers safe alternative to conventional batteries | Hacker News Reader

Aluminum battery from Stanford offers safe alternative to conventional batteries

news.stanford.edu

73 pointsmsoad30 comments

Likely as a direct response to the hype of this article (a few thousand comments in the related reddit thread), Elon tweeted:

    Battery "breakthroughs" need to state power *and*
    energy density (not the same thing), plus how long
    they last. They usually fail on energy.

https://twitter.com/elonmusk/status/585185843649716225

Stating the all the qualities is a good thing. But don't think all three must be good. Any two are enough to make a very successful battery.

Exactly. Energy density is a real bugaboo. Lemons with zinc in them are really economic and safe batteries, you can cut them, mash them, and literally make lemonade out of them. They grow on trees and just simple to make zinc strips. Except they can't power an LED for longer than about a minute. Admittedly they are not rechargable.

Which is not to slam the investigation into new (or rediscovered) battery chemistries. Just that the article goes out of its way to paint this as a huge break through, which it really isn't.

They grow on trees and just simple to make zinc strips. Except they can't power an LED for longer than about a minute. Admittedly they are not rechargable.

Electrodes can literally be had for pennies!

Or at least state the voltage of each cell, if it's going to be 1.2v per cell (replacing AA/AAA batteries) it's hardly something that can ever replace current LiX batteries in consumer electronics.

The article states the voltage to be 2v.

It's important to note, though, that this kind of breakthrough is hardly the kind of invention that Musk is interested in. The world of batteries doesn't revolve around Elon and Tesla.

This is sort of a big deal for those of us who design small electronic devices, not electric cars. Not having to factor in the potential fire hazard of a rechargeable battery for a keychain that the user has in his pocket or thrown in her purse or luggage is pretty useful -- and many such devices are thrown away along with their batteries, making them even bigger an environmental problem than they already are.

Even if these devices offer no improvement in terms of energy density, they're still a pretty big deal. It's also worth remembering that Li-Ion and even Li-Po batteries weren't necessarily stellar in terms of energy density when they were discovered, either -- they reached their current status through quite some industrial development.

It's also helpful if they can really stay steady at 2V (before the discharge cycle goes down abruptly), that would simplify 1.5V designs a lot, and help drive the space (and price!) further down.

The global energy storage market is and will continue to be driven by electric vehicles (no pun intended!) and consumer electronics. For these applications a faster charge/discharge is nice to have, a non-flammable material is nice to have but a high energy density is a MUST HAVE which Aluminum-ions don't.

My interpretation of a big deal is relative to the number of people it will positively influence. I wouldn't consider this a big deal, and in fact have heard the same claim at least once per month (ex. Titanium dioxide nanotube batteries http://www.gizmag.com/quick-charge-li-ion-battery/34347/).

The last time I read about this, it was expected that, at one point, in 2020 or so, electrical vehicle batteries are finally going to become a relatively important component of the battery market. There's a lot of money being poured into it because a lot of people are trying to move towards electric vehicles, but in terms of actual numbers being produced, the EVBs are dwarfed even by regular car batteries. Of course, EVBs are incredibly important, especially from an R&D perspective, but I don't think the market is being driven my them. My information may be a little out of date though.

As for consumer electronics, it's worth remembering that there are probably thousands of coin-cell operated keychains for every smartphone whose energy density capacity is not being satisfied by our current technology. There are a lot of consumer electronic devices for which current battery technology is OK -- better density would be an improvement, as it is everywhere, but it's no longer the hog it is for smartphones. For those, ease of recycling, lack of fire hazard and the slightly simpler circuitry really are important.

Those batteries have a lower energy density and power than the current li-ions, so you won't be seeing them in a phone, laptop or a car.

At the same time they are significantly cheaper to make and durable, which might make them a good solution for home energy storage - paired with panels for example.

Where does the article discuss the energy density?

I'm skeptical myself based on the number/style of claims they make, but I can't see any details.

  "Our battery produces about half the voltage of a typical lithium battery," he said. "But improving the cathode material could eventually increase the voltage and energy density. Otherwise, our battery has everything else you'd dream that a battery should have. [..]

Voltage is not the same as energy density. It's one component of it certainly, but not nearly enough by itself to tell you anything.

The linked article does not provide details. However, Engadget has an article on this that offers this tidbit:

"The aluminum-ion cell isn't perfect (yet) as it can only produce about 2 volts, far less than the 3.6V that lithium-ion an muster. Plus aluminum cells only carry 40 watts of electricity per kilogram compared to lithium's 100 to 206 W/kg power density."

http://www.engadget.com/2015/04/06/stanfords-battery-charges...

Sidenote: I suspect that passage means W-hours per Kg vs. W per Kg because typical Li-ion does have an energy density in the 100-200 W-h/kg range. See the chart in this Nature article:

http://www.nature.com/news/the-rechargeable-revolution-a-bet...

Even at only half the power I'd want one in my phone. It's easy enough to charge a phone if it only take a few minutes. It's the hours that it currently takes that makes frequent charging intolerable.

There are a bunch of options for that with li-ions too. For example Qualcomm claims that 3300mAh battery gets to 60% in 30 minutes with Quick Charge 2.0. Granted, that's not 'a couple of minutes', but still quite amazing.

I think someone did the testing and it's lower than that.

With something like that, something like the a battery at home could become viable. Even with the lower energy density, it has a few properties that are really great if it proves to be correct: no degradation on cycles, inexpensive and reduced fire hazard.

So imagine the Tesla Home Battery that would currently be double the size, at a lower price point, and could theoretically last a decade or two?

So there are definitely commercial options if it ever proves truly viable and can be easily manufactured.

I wish they bothered to state the expected energy density of these batteries. The fact that they didn't leads me to believe it's quite low compared to something like li-ion.

I believe this battery's density is not super impressive that they didn't mention in in the article and the title of the article is about it's safety rather that fast charging time or capacity

Safe and "high-performance" as they claim are somewhat opposing; to a battery that can be discharged at high currents, with a high energy density, there's no difference between dissipating that energy in the usual load it's powering and through a short circuit of equivalent resistance. Even if the battery itself doesn't catch fire or heat up, all that energy still has to go somewhere.

Safe here doesn't mean "can't kill you". Instead it means this chemistry doesn't exhibit thermal runaway (http://batteryuniversity.com/learn/article/lithium_ion_safet...)

Ugh, getting tired of all these articles that may not be untrue, but ought to live in science journals, properly read as experiments with new battery tech that could deliver to consumers 5-10 years later, rather than get posted on social media as if they're consumer-grade product launches. I've read tens of breakthroughs in batteries and solar and so on, in channels that had no interest in the science behind it. HN is mostly the exception to the rule.

Anyway, is there a battery guy that could explain to the rest of us what the state of battery innovation is like the next 10 years? Is it realistic to expect some big leaps? I really don't know what to expect and it'd be awesome to get some insider insights as to what kind of consumer-grade products we may see the next decade :) Thanks in advance.

Battery innovation is actually bottle-necked by the fact that over 90% of all anode materials are produced in China. So global adoption is ultimately dictated if manufacturing in China follows suit.

Unlike Americans, where we innovate with a short time horizon, China innovates and invest for generations (25-100 years). Thus, once a technology has been chose to be invested in overseas, the Chinese go "all-in".

The current paradigm shift is that Chinese anode material manufacturers are switching from graphite based electrodes to silicon nanoparticle based electrodes due to the fact that silicon nanoparticles have a theoretical energy density of ~4,000mAh/g, a 10x increase when compared to graphite which is only ~350mAh/g. There has been substantial research on silicon based lithium-ion batteries in the US for the past 7 years; it is now hitting a true inflection point.

This is one of the few "break-though" battery chemistries that is now entering full scale production - Panasonic is producing an 18650 cell made of silicon used by Tesla. *(see also Amprius, Envia,XG Sciences, etc.)

Tl;dr battery adoption is limited by adoption by Chinese manufacturers which control over 90% of the global anode material manufacturing. Silicon nanoparticles are taking over.

Sweet, thanks! So what would that (e.g. 10x the energy density) mean for consumers in practice. Can we expect 4x the range on a car, or the lifetime on a phone? Is this something we'll see around 2020, later, earlier?

Unfortunately, there are several items that interfere with maximizing the 10X. Then anode is only ~16% of the entire battery, so increasing the anode energy density by 10X does not translate directly to 10X battery life. You must also consider the cathode, and separator which can hinder this. Remember the 10X is a "theoretical maximum". It is important to constantly increase the theoretical maximum energy density. Translating the theoretical to an actual energy density is about downstream processing - see how Tesla increases battery efficiency each year by make the processing more efficient.

Amprius was promising 10X increase, but once they reach ton-scale manufacturing they were only able to get a 30-50% increase. I am sure they will be able to gradually increase close to the 10X maximum by making processing more efficient.

tl;dr battery material processing into the actual battery is where most of the batteries lose there performance. Step (1) Increase theoretical energy density by finding new material; Step (2) focus on battery processing to approach theoretical maximum.

I believe we will see it much earlier than 2020. The DOE has mandated that they want to see lithium-ion batteries 5X in capacity and 5X cheaper by 2020.

I think it can be done. If would happen much faster if we manufactured here and did not have to worry about international logistical and quality assurance associate with Chinese manufacturing.

> "Our rechargeable aluminum battery generates about two volts of electricity."

Now that's really good news. Stick it together with a 1.5V regulator inside an AA cell and never have problems with devices not accepting the 1.2V of a typical NiMH cell.

Alkaline batteries start at 1.5 V, but they do not stay there. They are 1.4 V when they have discharged by about 10%. When they have discharged by around 30%, they are at 1.3 V. When they have discharged by around 60%, they are at 1.2 V. By 90%, they are down to 1.1 V. By 95%, they are down to around 1.0 V, and they pretty much nosedive from there.

NiMH also drop as they are discharged, but the curve flattens out for much of its range. A good charger should charge an NiMH to around 1.4 V. After about 10% discharge, it will be down to 1.3 V. By 30% discharge it will be around 1.25 V, and it stays around that until around 80% discharge. From 80% to 90% it will drop to around 1.2 V, and from there it will drop to around 1.0 V at around 99% discharge, and then it falls off a cliff.

Devices designed for alkaline batteries are designed to run fine on anything from around 1.0 or 1.1 V through 1.5 V, and so should be fine with NiMH, except if they have a battery remaining indicator that is hard wired to assume alkaline it won't give accurate estimates for NiMH because of the different shapes of the discharge curves.

Why do we see a new "super battery" article every two weeks or so?

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