this post was submitted on 09 Oct 2023
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Design of zinc bromide flow battery (discuss.tchncs.de)
submitted 1 year ago by Rolive@discuss.tchncs.de to c/diy
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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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[–] perestroika 3 points 1 year ago* (last edited 1 year ago) (2 children)

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 however. 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]

It's probably doable, but not a particularly attractive technology when compared to alternatives.

[–] Rolive@discuss.tchncs.de 2 points 1 year 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.

[–] keepthepace 1 points 1 year 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?