Design of zinc bromide flow battery

Submitted ⁨⁨7⁩ ⁨months⁩ ago⁩ by ⁨Rolive@discuss.tchncs.de⁩ to ⁨diy@slrpnk.net⁩

This type of battery seems quite easy to DIY. Cheap materials, relatively safe, not flammable.

You can either maken individual cells or make a flow battery which is theoretically infinitely scalable. You’d be limited by the size of the electrode in how much power this battery can deliver.

Has anyone here tried to make a flow battery? And did you have any success with powering something large and energy consuming?

I guess it would also be possible to make a battery out of old buckets, carbon fiber mesh and separator material such as glass fiber.

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poVoq@slrpnk.net ⁨7⁩ ⁨months⁩ ago
While relatively easy to build, they seem quite complex to manage and have a risk of explosive hydrogen gas production and even toxic bromide gas in rare cases.

Probably not a DIY project that is easy over all.

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perestroika@slrpnk.net ⁨7⁩ ⁨months⁩ ago
No experience on that front, sadly.

Compared to iron redox flow batteries, it has about 5 percentage points of more efficiency (75 vs. 70%), slightly better cell voltage (1.8 vs 1.2 V) and better energy density per electrode surface (0.2 W vs 0.05 W / cm2).

The “resetting” of cells seems like a nuisance. Quoting Wikipedia:

Every 1–4 cycles the terminals must be shorted across a low-impedance shunt while running the electrolyte pump, to fully remove zinc from battery plates.[3]

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- Rolive@discuss.tchncs.de ⁨7⁩ ⁨months⁩ ago
  Hmm I didn’t notice the resetting part yet. That is indeed very inconvenient and not something I’m willing to build a system for.
  
  Perhaps just individual cells is better in that sense. My goal is a set and forget style battery that only needs maintenance in a few months.
  
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- keepthepace@slrpnk.net ⁨7⁩ ⁨months⁩ ago
  
  It’s probably doable, but not a particularly attractive technology when compared to alternatives.
  
  Wondering why you feel that way? It would be easy to design packs of 4 that would have rotations where one cell does the resetting cycle while the others do the regular one? Is the reset cycle as long as the recharge one btw?
  
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corship@feddit.de ⁨7⁩ ⁨months⁩ ago
Yeah great idea, let’s bring back bromism

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- Rolive@discuss.tchncs.de ⁨7⁩ ⁨months⁩ ago
  The bromine stays in the cell. It’s not meant for human consumption.
  
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  - corship@feddit.de ⁨7⁩ ⁨months⁩ ago
    Instructions unclear, dock got stuck in acid.
    
    Jokes aside, my point is the “ermahgerd let’s build some batteries with buckets and wire”
    
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- Uranium_Green@sh.itjust.works ⁨7⁩ ⁨months⁩ ago
  Lmao, do you drink your Li-po batteries as well?
  
  The typical dose needed to reach bromism (when talking about old bromide sedatives) is 0.5g-1.0g a day, the lethal dose of zinc bromide is 3-5g, those levels are not passive exposure levels, they’re intentional or very unlucky accidental ingestion levels
  
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  - corship@feddit.de ⁨7⁩ ⁨months⁩ ago
    Lmao, do you manufacture your li-po batteries as well?
    
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