Nickel-iron battery DIY project

Discussion in 'Electronics & Electrics' started by ShadowBurger, Aug 21, 2017.

  1. ShadowBurger

    ShadowBurger Member

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    Hi all,

    I'm thinking of embarking on a project to build some nickel-iron batteries ("Edison cells") for use with solar. Just wondering if anyone else (especially local to 3809) would be interested in teaming up? For those who don't know what they are, here's a summary of their properties. They seem like an excellent cell for solar use

    Nickel-iron batteries:

    • Don't sulphate like lead-acid batteries. Sources suggest batteries as old as 70 years still in service, with only maintenance of the electrolyte
    • Suffer no damage when overcharged
    • have a nominal voltage about 1.2v
    • will hold about 1.5ah for a jar-sized DIY cell
    • Use a Nickel II (NiOH2) positive electrode
    • Use an Iron Oxide (Fe3 O4) negative electrode
    • Use an alkaline instead of an acidic electrolyte

    Source - white paper #1 and #2 found here: https://www.noonco.com/edison/improvements.htm
     
    Last edited: Aug 21, 2017
  2. Sunder

    Sunder Member

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    I had considered building a prototype to see if the claimed capacity and internal resistances were achievable, then building fish-tank sized cells if it works out well. I put it on hold because things got too hectic at work, and never picked it up again.

    If you get a decent group buy going with a supplier, I would be interested. Not sure if shipping to Sydney would wipe out any savings though... As I noted when trying to source professionally made ones from China, the cell price itself is fairly reasonable. Shipping that amount of weight kills you.
     
  3. OP
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    ShadowBurger

    ShadowBurger Member

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    interesting point. I wonder if we could source just electrodes from that supplier, then assemble them ourselves? I would think the majority of the shipping cost would be in the electrolyte weight and volume of the batteries overall

    EDIT: This nickel foam looks like it might be the best way to proceed? LINK. I'm not totally sure what to use for the other electrode which needs to be iron oxide

    EDIT2: I'm thinking the foam would be excellent and would allow the construction of a 'rolled' cathode/separator/anode design which would hugely increase the surface area

    Also a good read on DIY construction: http://www.nutsvolts.com/magazine/article/february2012_Noon
     
    Last edited: Aug 21, 2017
  4. Sunder

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    The quotes I got was for dry shipping. That is, they shipped the batteries to you with the "electrolyte" in powder form, and you add your own distilled water.

    I was looking at over a metric ton for the size I wanted. (I can't remember what I decided on, but I think it was around 20kwh).

    What's the iron nickel foam used for? Is that the positive electrode? Just like some people use steel or copper mesh that has been nickel plated as the positive electrode?
     
  5. OP
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    ShadowBurger

    ShadowBurger Member

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    Darn. Still, they are big units. I just sent a few enquiries to sellers on aliexpress to see if they'll sell just electrode sets. It may be possible to use big plastic storage containers to cheaply make some monster size cells

    Exactly, yeah. It should never corrode so highly porous nickel foam should make an excellent electrode. I think it still might need to be coated with the nickel II though. I'm still figuring out exactly how to differentiate the two materials when dealing with suppliers of nickel powder and whatnot.

    This was pretty inspiring:

    If the capacity per kg is that good using batteries that old, something even better should be achievable using modern manufacturing techniques. That nickel foam surely wouldn't have been possible back in 1910?

    I still don't know what to use for the other electrode. All sources suggest using a peice of iron but doesn't the electrolyte eat away everything but nickel?
     
  6. macrocephalic

    macrocephalic Member

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    It's an interesting idea, but I doubt it will be economical. Assuming that a 1L mason jar gives you a battery of 1.5ah at 1.2v, that's 1.8wh/L, or 1.8kwh/m^3. A common solar battery is between 3 and 15kwh. To get the same storage capacity as a Tesla powerwall, you'd need to fill up a room the size of bathroom.

    Lithium batteries for solar are below 20c/warranted kwh now (which is only roughly on par with current residential supply prices). Assuming that this nickel battery lasts forever it will eventually pay itself off, but you could be waiting a very long time.
     
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    ShadowBurger

    ShadowBurger Member

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    I actually understated the capacity there... that was the capacity of one of the hobby cells made by the author of the white paper, who just used two basic electrode plates, instead of a high-surface area design or multiple plates. According to the document, you could expect 1.25ah per 10cm of electrode if using a perforated nickel tube type design. I'm hoping to find a way to make a roll consisting of nickel II plated foam, an insulator, and the iron oxide plated foam, like so:

    [​IMG]

    which I hope can maximise the use of the space inside a mason jar to provide something like 8ah of capacity
     
  8. bryn

    bryn Member

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    i might be interested, I am in Sydney tho
     
  9. Sunder

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    I was thinking like you, but instead of rolling, make it like a wafer biscuit with appropriate insulator. Would need to test if there is an optimum point where the electrodes displace so much electrolyte that you start losing capacity.

    Even if national group buy is not possible, perhaps sevetal regional ones would be. Although, it seems Sydney has the most interest so far.
     

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