This video seems to be AI generated and doesn't have that much real information? I have seen Ca-ion systems from (I think) a German group that looked good, but had a lot of organic synthetic steps if I remember correctly.
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Using cnc router cut PVC foam boards as cell frame@rowow said in Using cnc router cut PVC foam boards as cell frame:
The long term goal and my personal next goal is to get into injection molding which of course is the best option.
At scale, definitely!
@rowow said in Using cnc router cut PVC foam boards as cell frame:
Ill see about uploading the cell fusion 360 model
A
.stepfile would also be great so I could look at it in FreeCAD! I don't have a Fusion 360 license. I'd be curious to see if we could take a similar approach. -
You Tuber Video on an open source all Iron batteryNice find! Peter Allen has been at it for a while. I'd read his previous papers but not this one. A quick scan shows they are using an ion-exchange membrane, which @danielfp248 and I try to avoid if we can, since they are often the weak point of systems that rely on them.
Crossover of the mediators through the membrane will degrade performance. The possibility of this unwanted feature was examined by cyclic voltammetry on an electrochemical cell divided by the Fumasep FAS-50 anion exchange membrane in the 2 M KCl 20 % (v/v) EG AIB 3.0 electrolyte. The initial concentrations were 10 mM MV2+ in the left chamber and 10 mM ABTS2- in the right. A constant potential of 1.25 V was applied across the cell with 6.25 cm2 graphite electrodes for 24 h. This simulates the AIB 3.0 conditions. After the 24 h period CV was performed on catholyte to evaluate MV crossover and vice versa. We found no crossover through the membrane by the cyclic Voltammetry experiments.
I like how everything is commercially available at scale. There are quite a few organic flow battery startups that have tried to use methyl viologen as well like they do in this paper. I am curious what @danielfp248 thinks
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Upcoming improvements to the dev kit@doho said in Upcoming improvements to the dev kit:
I have try-ed to download Your new files from github (.stl and .pdf), but the files all appeared as broken, even in github.
The files to sprint for the new endplates are here: https://codeberg.org/FBRC/RFB-dev-kit/src/branch/clampable-cell/CAD/exports
I haven't updated the new
You have to download them individually, unless you clone the repository with Git LFS set up---the large CAD files are handled with LFS and without LFS installed downloading the repository just downlaods a pointer/reference to the CAD file, not the actual file (at least that's how I understand it).
Let me know if this works for you!
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My Suction Luer LockVery nice work @doho ! It's great to see your setup.
@doho said in My Suction Luer Lock:
But for getting reproducible resultants the flow through the cell should be down to up, but not horizontal (how much would be air isolating in the chamber when changing parts?)
This is a good point, from what I've seen in other applications cells should generally clear air/produced gases by flowing against gravity from bottom to top, that is still possible with the new setup but the tubing from the pump outlet to cell inlet would have to be slightly longer. In my jig redesign I'll take this into account when writing the documentation.
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Upcoming improvements to the dev kitAlso, we have a "double-reservoir" part that contains an internal spillover passage for systems that have a lot of water/liquid transfer. Probably going to make a version with and without this and have it as the standard going forward, to simplify the tubing and jig setup for whatever version people want to use.
The double-reservoir with spillover is in use here
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Upcoming improvements to the dev kitOh, and we'll be trying to add Luer Lok twist connectors to make detaching the cell quickly from the rest of the setup faster/easier than undoing tight barbed fitting connections.
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Upcoming improvements to the dev kit
The new endplates are basically the same, just two alignment pins instead of four bolt holes.
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Upcoming improvements to the dev kitHi all, been planning some improvements to the dev kit that are underway, based on some ideas exchanged at a conference with some other open-source flow battery projects (Redoxino and the team at QUB).
It's mostly to improve ergonomics - there is now a case to hold the arduino and wires on the rear of the cell:
We also realized you can just clamp the cell shut with a 2-inch C-clamp instead of using the bolts, and it seals well:
Note, the new endplates here used are backwards-compatible with previous gaskets/graphite plates/brass current collectors, so no need to recut anything. Moving forward though, the design files for those components will change to reflect the need for only two alignment pin holes instead of the four bolt holes.
And based on Redoxino's presentation at the Nordic Flow Battery Network meeting, Gastronorm (GN) containers are a nice standard to use for secondary containment, it seems with some tweaks we could fit the entire kit into a GN 1/3 150 mm deep container, which are a standard for industrial kitchens worldwide (and available in polymers like PP and PC).
Need to make the reservoirs shorter or mounted lower somehow, and maybe make a holder in the jig for the C-clamp, so that it's in a fixed position.
Right now I'm working on these developments on the
clampable-cellbranch here: https://codeberg.org/FBRC/RFB-dev-kit/src/branch/clampable-cellLet me know if you have feedback/ideas/suggestions! Docs are not yet updated for this configuration, I will do that before I merge it to main.
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New ion exchange membrane recipe using water softener resin and PVC cementFirst off, @rowow , thanks for making your membrane approach open-source! Out of curiosity, is the patent application alongside it meant to prevent patent trolls from taking advantage of it?
@danielfp248 has looked into membranes quite a bit and I agree that the only way to know for sure about a membrane's chemical compatibility is to test it with the proposed electrolyte during operation, where it will be exposed to, to take our standard zinc-iodide cell as an example, zinc dendrites (which can puncture an IEM) and high concentrations of triiodide, which can be pretty aggressive and "weird", in the sense that it has attacks and goes through many polymers that are otherwise resistant to similar classes of chemicals.
So far we've used paper and Daramic (polyethlyene + silica microporous separators used in lead-acid cells) because our chemistries are meant to be symmetric (and can tolerate mixing) and they are generally quite chemically resistant and handle dendrites better than an IEM. We're not against IEM use by any means, but so far we haven't spent much time on them because of the previously mentioned problems, and it's not our main focus/skill set. We've had our hands full with electrolyte development and cell/system design, so we've essentially opted to keep the membrane "can of worms" (from our perspective) closed---that said, it would be really interesting to test your membrane approach in the dev kit with say, Zn-I, to see how it compares to Daramic---I just don't think we have the time right now to fabricate the membranes ourselves.
It seems you probably have most of the resources already to test your membranes with ZnI? The other thing that would be quite different in terms of membrane requirements for a battery vs. a refining process would be conductivity, I'm not sure if you've done measurements in terms of Ohm*cm² but this would be a harder target to reach for RFB applications.
