8 ms·

Open source all-iron battery for renewable energy storage

137 points by stevewilhelm 7y ago

Causality1 7y ago
Lithium ion battery prices are currently below $0.17 per watt-hour and expected to drop below $0.10 by 2024. Does the all iron battery have any advantages aside from being more environmentally friendly and not requiring lithium? I must admit, the "safe for DIY" description makes me want to give it a try.
- bigiain 7y ago
  I'm also curious about it's potential to be built from recycled/junkyard resources, instead of needing access to rare earth metals. (Perhaps post-apocalyptically...)
  - maxerickson 7y ago
    Just go with lead-acid in the apocalypse. Embrace the aesthetic.
- dredmorbius 7y ago
  Iron is extremely abundant. It's too heavy for most mobile applications, but might serve stationary needs.
  - solarkraft 7y ago
    Lithium batteries from EOL cars are also going to become extremely abundant.
    - majewsky 7y ago
      Maybe in 20 years. As usage of electric cars is still ramping up, demand for new batteries is going to outstrip supply of old batteries by far. And that's before we ask how difficult it is to extract raw materials from old batteries.
      - mceachen 7y ago
        FWIW, the majority of the EV fleet with air-cooled batteries in hotter US states (like Arizona) are already needing battery replacements after ~5 years. See LEAF and eGolf.
      - solarkraft 7y ago
        FWIW, my city (Lünen, Germany) has 2 Multi-MWh storages built from them (1 from batteries from Smart cars, 1 possibly from i-MiEV batteries). Without any material-level recycling, just simple reuse, as energy density is a lot less important than for cars. Maybe having 2 of those (admittedly pilot) projects in my backyard biases my estimations of their availability.
- ed_balls 7y ago
  My understanding is that Lithium is not a big problem. Cobalt is more rare.
  - Gibbon1 7y ago
    Last time I looked that appeared to be the case. Lithium is extracted[1] from primary sources. The rub then is that supply is limited by low historical demand and can be fixed by tapping other sources. The supply demand curve is thus just steep in the short term. Cobalt is mostly a by-product of copper mining. Being a by-product means it's highly supply constrained. So the supply demand curve is very steep over the short, medium and long term. [1] Leached from salt deposits or extracted from saline water sources.
blacksqr 7y ago
+1 for discovering that a polymer used in diapers for absorbing moisture is a cheap and effective ion-permeable separator membrane.
- benj111 7y ago
  Unfortunately only mentioned once. Are we talking about the granules inside the nappy here? Also doesn't seem to have instructions for processing it beyond the short description.
philipkglass 7y ago
A fundraising appeal for this project was posted to HN in 2017: https://news.ycombinator.com/item?id=15618494 https://news.ycombinator.com/item?id=15618494 I contributed. It's great to see the results published.
edent 7y ago
This looks amazing - and great to see such detailed instructions. One thing to note is that this probably isn't yet ready for home storage of solar power. "Our iron battery has sufficient capabilities for practical use in low power devices and projects. The cell’s internal resistance is high, and so the discharge rate is limited." At the moment it could be useful as a backup for high efficiency lighting. The bill of materials doesn't cover any electronics to monitor and maintain the cells as the charge/discharge. But all pretty nifty!
- dredmorbius 7y ago
  Creating compound battery (and other storage) designs to address capacity, cost, and instantaneous peak demand might be fruitful. Capacitors and flywheels make lousy bulk storage but are excellent for smoothing power demand and spinning reserve.
- kragen 7y ago
  No, it doesn't provide enough power for high efficiency lighting, or any lighting. Yet.
  - chabes 7y ago
    In the article, it describes keeping an LED lit for 350 continuous hours. Lots of room for improvement too
    - kragen 7y ago
      An LED with 0.5 mA going through it is definitely visually distinguishable from one that's off, but it's not “lighting” either, except maybe for Borrowers in a romantic mood, or ants.
      - chabes 7y ago
        A single LED emits plenty of light. Just not compared to daylight. And this was for many days..
0wis 7y ago
Great detailed publication ! Makes me want to build one. Curious to know how much efficient this battery can become without using too hard to source material ! And for which kind of cycles. Even if components are environmentally friendly, electricity production is never footprint free, so if you need to 2x it to compensate...
kator 7y ago
What are the odds the steel wool could catch fire on these?
- rini17 7y ago
  Only if the electrolyte dries out, and even then it will be probably covered by salt crust.
crispyambulance 7y ago
It makes me think of the Acquion project from Pittsburgh (http://aquionenergy.com/ http://aquionenergy.com/). That was an interesting attempt to commercialize environmentally safe batteries intended for uses where low power density isn't a problem-- eg underground energy storage for windfarms or solar arrays. They went bankrupt a couple years ago, but the concept was really exciting. The immediate technical challenge with these kind of batteries at scale is the electronics to monitor and maintain the battery banks as well as deploying these things. It would take a truckload to set-up something usable for a house, I think.
s_Hogg 7y ago
This reminds me of the cheap water purification thing that got rolled out across poorer bits of Africa. Any cost reduction possibilities for this design?
dcahill-ieee 7y ago
It made 1mA of current, 0.5mW of power. Pretty long bow to draw linking this to renewable energy storage. A kettle uses a kW or 2 just to boil water. You would need a million of them to make a packet of noodles.
- tsroe 7y ago
  "just to boil water" has got to be the biggest understatement that I've heard in a while. There is a reason we use water in radiators: It's because water has a very high heat capacity. I think this battery is meant to be used in small electronics projects. Like powering an arduino or even just an ATTINY.
  - tapland 7y ago
    How did you get that impression from reading what you linked?
    - Spidler 7y ago
      From the article: > The pouch cell as described, can provide ∼1 mA of current. At the typical operating voltage of ∼0.5v, each cell can provide ∼0.5mW. The cell is robust to at least ten cycles of charge and discharge without noticeable loss in capacity. An array of 6 cells is thus sufficient for low current electronics for sensing applications (such as low power microcontrollers like Texas Instruments MSP430). It's research into making safe, DIY rechargeable batteries, which is pretty damned cool.
      - tapland 7y ago
        The reason the first person commented is because it's clearly touted as a solution intended for large scale batteries for renewable energy. Restating that part doesn't change that, and it never states that use case as an intended application.
  - ninkendo 7y ago
    > "just to boil water" has got to be the biggest understatement that I've heard in a while. It’s also a good illustration of how much we depend on extreme energy densities for everyday use cases. Coming up with a good storage solution for renewable fuels is going to be a defining challenge for our generation.
xvilka 7y ago
Curiously, the article has a link[1] to the sources, located at OSF (Open Science Foundation), but it asks for the login first, not allowing to view without registration. Doesn't look like open science to me. [1] https://osf.io/4jvr9/ https://osf.io/4jvr9/
- lazypenguin 7y ago
  Clicking the "download" link with the pdf icon at the top gave me access to the entire pdf https://www.sciencedirect.com/science/article/pii/S2468067219300318/pdfft?md5=9b80bd4a023bb227ff43f2dc066b936b&pid=1-s2.0-S2468067219300318-main.pdf https://www.sciencedirect.com/science/article/pii/S246806721...
cagenut 7y ago
I skimmed through looking for some key numbers but didn't find them. I bet someone who knows how to read the many numbers they did share would be able to hazard a guess: what would the $/kWh look like? how many cycles until you hit 90%, 80%, 50% capacity?
- std_throwaway 7y ago
  100 $/kWh
kragen 7y ago
Certainly iron is the metal to look at if you're going for the lowest cost, but the results so far are not inspiring. There are about nine orders of magnitude in between these results and utility-scale energy storage, but it doesn't seem like that's what they're aiming for—the existing flow batteries they mention in the paper would be a better fit. They seem to be aiming at home applications, but they are seven orders of magnitude away from even the “tens of kilowatts” they cite in their abstract as typical for such applications. However, both the negative results they mention in passing and the positive ones are major contributions to the progress of such low-cost battery designs. Iron costs around US$0.03 per kg, while lithium is more like US$300 and nickel is US$30. In the intervening 3 orders of magnitude, cheaper than nickel but not as cheap as iron, are aluminum, antimony, arsenic, cadmium, carbon, cerium, chromium, copper, lead, manganese, samarium, silicon, tin, titanium, vanadium, and zinc. Some of these are unpromising precisely because they are too electronegative; zinc, as they said, cannot be reduced electrolytically in water; the same problem applies to titanium, aluminum, and carbon—but maybe a different electrolyte could solve that problem. Others, like lead, are already in common use for batteries. Chromium, titanium dioxide, vanadium, tin and tin oxide, copper, manganese and its oxides, cerium, samarium, and of course lead seem like plausible candidates. Indeed at least zinc-cerium batteries exist.
- tim333 7y ago
  I'm not sure their materials even sound all that cheap. From the article "The total cost of materials is $0.1 per watt-hour" Or presumably $100/kWh On the other hand with Zinc Air "our fundamental raw material cost of zinc is just $2-$3/KWh." from https://www.altenergymag.com/article/2019/03/zinc-air-battery-technology/30652 https://www.altenergymag.com/article/2019/03/zinc-air-batter... talking about NantEnergy's rechargables.
  - maxerickson 7y ago
    Yeah, the interesting comparison is the energy storage per dollar, not the cost of the raw materials.
    - 7y ago
nickcw 7y ago
To put the costs intro perspective, an 83 Amp Hour car battery (typically a small car might have a 40-60 AH battery and a large car >100 AH) holds 1 kWh (kilo watt hour). An 80AH battery can be had for about $100 on eBay. The article states that the cost of materials might be $100/kWh. So you could get the storage for about the same price using a car battery.
Animats 7y ago
Actual paper.[1] This looks like someone's science fair project. This chemistry has lower energy density than nickel-iron (Edison, 1901). Iron batteries are commercially available.[2] Not much of interest here. [1] https://reader.elsevier.com/reader/sd/pii/S2468067219300318 https://reader.elsevier.com/reader/sd/pii/S2468067219300318 [2] https://www.essinc.com/energy-storage-products/ https://www.essinc.com/energy-storage-products/

137 points by stevewilhelm 7y ago

Lithium ion battery prices are currently below $0.17 per watt-hour and expected to drop below $0.10 by 2024. Does the all iron battery have any advantages aside from being more environmentally friendly and not requiring lithium? I must admit, the "safe for DIY" description makes me want to give it a try.

bigiain 7y ago
I'm also curious about it's potential to be built from recycled/junkyard resources, instead of needing access to rare earth metals. (Perhaps post-apocalyptically...)
- maxerickson 7y ago
  Just go with lead-acid in the apocalypse. Embrace the aesthetic.
dredmorbius 7y ago
Iron is extremely abundant. It's too heavy for most mobile applications, but might serve stationary needs.
- solarkraft 7y ago
  Lithium batteries from EOL cars are also going to become extremely abundant.
  - majewsky 7y ago
    Maybe in 20 years. As usage of electric cars is still ramping up, demand for new batteries is going to outstrip supply of old batteries by far. And that's before we ask how difficult it is to extract raw materials from old batteries.
    - mceachen 7y ago
      FWIW, the majority of the EV fleet with air-cooled batteries in hotter US states (like Arizona) are already needing battery replacements after ~5 years. See LEAF and eGolf.
    - solarkraft 7y ago
      FWIW, my city (Lünen, Germany) has 2 Multi-MWh storages built from them (1 from batteries from Smart cars, 1 possibly from i-MiEV batteries). Without any material-level recycling, just simple reuse, as energy density is a lot less important than for cars. Maybe having 2 of those (admittedly pilot) projects in my backyard biases my estimations of their availability.
ed_balls 7y ago
My understanding is that Lithium is not a big problem. Cobalt is more rare.
- Gibbon1 7y ago
  Last time I looked that appeared to be the case. Lithium is extracted[1] from primary sources. The rub then is that supply is limited by low historical demand and can be fixed by tapping other sources. The supply demand curve is thus just steep in the short term. Cobalt is mostly a by-product of copper mining. Being a by-product means it's highly supply constrained. So the supply demand curve is very steep over the short, medium and long term. [1] Leached from salt deposits or extracted from saline water sources.

blacksqr 7y ago

+1 for discovering that a polymer used in diapers for absorbing moisture is a cheap and effective ion-permeable separator membrane.

benj111 7y ago
Unfortunately only mentioned once. Are we talking about the granules inside the nappy here? Also doesn't seem to have instructions for processing it beyond the short description.

philipkglass 7y ago

A fundraising appeal for this project was posted to HN in 2017: https://news.ycombinator.com/item?id=15618494 https://news.ycombinator.com/item?id=15618494 I contributed. It's great to see the results published.

edent 7y ago

This looks amazing - and great to see such detailed instructions. One thing to note is that this probably isn't yet ready for home storage of solar power. "Our iron battery has sufficient capabilities for practical use in low power devices and projects. The cell’s internal resistance is high, and so the discharge rate is limited." At the moment it could be useful as a backup for high efficiency lighting. The bill of materials doesn't cover any electronics to monitor and maintain the cells as the charge/discharge. But all pretty nifty!

dredmorbius 7y ago
Creating compound battery (and other storage) designs to address capacity, cost, and instantaneous peak demand might be fruitful. Capacitors and flywheels make lousy bulk storage but are excellent for smoothing power demand and spinning reserve.
kragen 7y ago
No, it doesn't provide enough power for high efficiency lighting, or any lighting. Yet.
- chabes 7y ago
  In the article, it describes keeping an LED lit for 350 continuous hours. Lots of room for improvement too
  - kragen 7y ago
    An LED with 0.5 mA going through it is definitely visually distinguishable from one that's off, but it's not “lighting” either, except maybe for Borrowers in a romantic mood, or ants.
    - chabes 7y ago
      A single LED emits plenty of light. Just not compared to daylight. And this was for many days..

0wis 7y ago

Great detailed publication ! Makes me want to build one. Curious to know how much efficient this battery can become without using too hard to source material ! And for which kind of cycles. Even if components are environmentally friendly, electricity production is never footprint free, so if you need to 2x it to compensate...

kator 7y ago

What are the odds the steel wool could catch fire on these?

rini17 7y ago
Only if the electrolyte dries out, and even then it will be probably covered by salt crust.

crispyambulance 7y ago

It makes me think of the Acquion project from Pittsburgh (http://aquionenergy.com/ http://aquionenergy.com/). That was an interesting attempt to commercialize environmentally safe batteries intended for uses where low power density isn't a problem-- eg underground energy storage for windfarms or solar arrays. They went bankrupt a couple years ago, but the concept was really exciting. The immediate technical challenge with these kind of batteries at scale is the electronics to monitor and maintain the battery banks as well as deploying these things. It would take a truckload to set-up something usable for a house, I think.

s_Hogg 7y ago

This reminds me of the cheap water purification thing that got rolled out across poorer bits of Africa. Any cost reduction possibilities for this design?

dcahill-ieee 7y ago

It made 1mA of current, 0.5mW of power. Pretty long bow to draw linking this to renewable energy storage. A kettle uses a kW or 2 just to boil water. You would need a million of them to make a packet of noodles.

tsroe 7y ago
"just to boil water" has got to be the biggest understatement that I've heard in a while. There is a reason we use water in radiators: It's because water has a very high heat capacity. I think this battery is meant to be used in small electronics projects. Like powering an arduino or even just an ATTINY.
- tapland 7y ago
  How did you get that impression from reading what you linked?
  - Spidler 7y ago
    From the article: > The pouch cell as described, can provide ∼1 mA of current. At the typical operating voltage of ∼0.5v, each cell can provide ∼0.5mW. The cell is robust to at least ten cycles of charge and discharge without noticeable loss in capacity. An array of 6 cells is thus sufficient for low current electronics for sensing applications (such as low power microcontrollers like Texas Instruments MSP430). It's research into making safe, DIY rechargeable batteries, which is pretty damned cool.
    - tapland 7y ago
      The reason the first person commented is because it's clearly touted as a solution intended for large scale batteries for renewable energy. Restating that part doesn't change that, and it never states that use case as an intended application.
- ninkendo 7y ago
  > "just to boil water" has got to be the biggest understatement that I've heard in a while. It’s also a good illustration of how much we depend on extreme energy densities for everyday use cases. Coming up with a good storage solution for renewable fuels is going to be a defining challenge for our generation.

xvilka 7y ago

Curiously, the article has a link[1] to the sources, located at OSF (Open Science Foundation), but it asks for the login first, not allowing to view without registration. Doesn't look like open science to me. [1] https://osf.io/4jvr9/ https://osf.io/4jvr9/

lazypenguin 7y ago
Clicking the "download" link with the pdf icon at the top gave me access to the entire pdf https://www.sciencedirect.com/science/article/pii/S2468067219300318/pdfft?md5=9b80bd4a023bb227ff43f2dc066b936b&pid=1-s2.0-S2468067219300318-main.pdf https://www.sciencedirect.com/science/article/pii/S246806721...

cagenut 7y ago

I skimmed through looking for some key numbers but didn't find them. I bet someone who knows how to read the many numbers they did share would be able to hazard a guess: what would the $/kWh look like? how many cycles until you hit 90%, 80%, 50% capacity?

std_throwaway 7y ago
100 $/kWh

kragen 7y ago

Certainly iron is the metal to look at if you're going for the lowest cost, but the results so far are not inspiring. There are about nine orders of magnitude in between these results and utility-scale energy storage, but it doesn't seem like that's what they're aiming for—the existing flow batteries they mention in the paper would be a better fit. They seem to be aiming at home applications, but they are seven orders of magnitude away from even the “tens of kilowatts” they cite in their abstract as typical for such applications. However, both the negative results they mention in passing and the positive ones are major contributions to the progress of such low-cost battery designs. Iron costs around US$0.03 per kg, while lithium is more like US$300 and nickel is US$30. In the intervening 3 orders of magnitude, cheaper than nickel but not as cheap as iron, are aluminum, antimony, arsenic, cadmium, carbon, cerium, chromium, copper, lead, manganese, samarium, silicon, tin, titanium, vanadium, and zinc. Some of these are unpromising precisely because they are too electronegative; zinc, as they said, cannot be reduced electrolytically in water; the same problem applies to titanium, aluminum, and carbon—but maybe a different electrolyte could solve that problem. Others, like lead, are already in common use for batteries. Chromium, titanium dioxide, vanadium, tin and tin oxide, copper, manganese and its oxides, cerium, samarium, and of course lead seem like plausible candidates. Indeed at least zinc-cerium batteries exist.

tim333 7y ago
I'm not sure their materials even sound all that cheap. From the article "The total cost of materials is $0.1 per watt-hour" Or presumably $100/kWh On the other hand with Zinc Air "our fundamental raw material cost of zinc is just $2-$3/KWh." from https://www.altenergymag.com/article/2019/03/zinc-air-battery-technology/30652 https://www.altenergymag.com/article/2019/03/zinc-air-batter... talking about NantEnergy's rechargables.
- maxerickson 7y ago
  Yeah, the interesting comparison is the energy storage per dollar, not the cost of the raw materials.
  - 7y ago

nickcw 7y ago

To put the costs intro perspective, an 83 Amp Hour car battery (typically a small car might have a 40-60 AH battery and a large car >100 AH) holds 1 kWh (kilo watt hour). An 80AH battery can be had for about $100 on eBay. The article states that the cost of materials might be $100/kWh. So you could get the storage for about the same price using a car battery.

Animats 7y ago

Actual paper.[1] This looks like someone's science fair project. This chemistry has lower energy density than nickel-iron (Edison, 1901). Iron batteries are commercially available.[2] Not much of interest here. [1] https://reader.elsevier.com/reader/sd/pii/S2468067219300318 https://reader.elsevier.com/reader/sd/pii/S2468067219300318 [2] https://www.essinc.com/energy-storage-products/ https://www.essinc.com/energy-storage-products/