Flow Battery Research Collective

@kirk said in Following your documentation – feedback & questions: Could you share the file you modified? It looks like you added a big cylinder. I have send you an email, @kirk said in Following your documentation – feedback & questions: The program here * should * work on linux when run as root (in order to have proper USB access). You can control the pump speeds via the Arduino with the software, even without the MYSTAT connected (under the "charge/discharge" tab) (this will all hopefully be in a video soon!) Thank you. I am planning to use a Raspberry Pi for long-term tests. Are you using a Raspberry Pi too, or a PC? @kirk said in Following your documentation – feedback & questions: In the CAD files we have specified a 2D endplate (https://codeberg.org/FBRC/RFB-dev-kit/src/branch/main/CAD/exports/Metal Endplate.step), that could be laser cut or milled from aluminum. @danielfp@chemisting.com has received endplate versions of this in aluminum, the only catch is then you need insulating washers so as to not short them. Another rigid polymer could work too. Thank you. For now, if there are no leaks during the long-term tests, I will not change these endplates. And also, I wanted to ask you about the current collector's material – is brass a better option than pure copper? What was the criterion for the material type and thickness selection?

@gus @SamAuc ABS may work with an all-copper chemistry!

Updates from @danielfp@chemisting.com during today's meeting: I started a test with 2M KI, 1M ZnCl2, 2M NH4Cl, 5% Trieg with Daramic and felt on both sides. Going to charge to 1.6V at 10mA/cm2, see if it makes any difference regarding stability with Trieg on subsequent cycles. I did one cycle at 10mA/cm2, charged to around 240mAh (noticed a dip indicating start of solid I2 buildup, so cut it there), discharged 180mAh. I am now charging to 150mAh at 30mA/cm2, normally I would see drops in capacity with cycling with Trieg at this level, we'll see if they happen. [image: 1747325869007-57810618-3e33-4f12-ad81-bc93fc620bcd-image.png] Seems to be stable now at 30mA/cm2. I will leave it cycling here longer, see if it starts decaying. [image: 1747325889390-778d48dc-3d94-4012-9de2-a0c45a4727b0-image.png] ok, went for 9 cycles with no issues at all. I am now going to cycle it to 1.65V, to the Nernst limit, see if it continues working equally well. Charging to 1.65V showed the weird start for the discharge curve, although with no apparent deterioration of the cycle characteristics after the first cycle. No evidence for solid iodine formation was present, so the solution is very well behaved. [image: 1747325914186-cc5413ce-ad2d-4ae5-b64d-ed8939f213cf-image.png] Test at 15mA/cm2 of the same cell. Some deterioration is now evident, charging to 1.55 V [image: 1747325934195-2dbc77b1-de09-4492-a3e2-5997e2517c81-image.png]

Hi Otmar! I think it would be helpful to see a rough schedule of the workshop and time allocations per topic/activity - then it would be easier to give feedback for the site, based on specifics of the activity the site is meant to complement!

From Roth et al., Aalto University built a (sizable!) stack for all-copper and used ABS for their flow frames - I'd imagine it would play better with BPT tubing than the Zn-I chemistry also.

Cloning the https://codeberg.org/FBRC/RFB-dev-kit repository, opening the assembly in FreeCAD, fixing part of it, then pushing the changes with VSCodium. As part of the Flow Battery Research Collective project at https://fbrc.dev 0:00 Cloning repository 3:29 Opening assembly file 4:09 Fixing the cell assembly 20:20 Pushing changes to repository

Doing some preliminary design for a flow frame that could be printed with a common FDM printer - side length 200 mm. More to come soon! [image: 1746549456826-0a9be9ec-5073-4eb6-b3c0-52c7a42e9e3c-image.png]