Flow Battery Research Collective

I'm also interested in this topic. Polypropylene is not a trouble-free material. There are some other filaments classified as chemically resistant (https://help.prusa3d.com/filament-material-guide). Is PP the only suitable option?

I didn’t want to take over the “New member introduction thread” with my questions, so I’ve started a new one.

At this point, I already have the 3D printed components. I should receive the remaining parts later this month.

One thing I was missing in the documentation was information about the material for the "polymer endplate". In the photo, “PETG 100%” was written on the endplate with a marker, so I used that material and infill.

Hi! I work at a technical university, in the mechanical engineering faculty. I'd like to build your prototype based on the documentation. Flow batteries are a new topic for me, but they could be very useful in my field, and this seems like a great way to get to know them better. I also saw your presentation on YouTube. I was about to ask about the peristaltic pump model, but I noticed you’ve just updated the documentation This forum looks really helpful in case I need any support or clarification. I’ll try to give some feedback if it’s useful to you.

@kirk Thank you! I'm starting to 3D print all the components.

The bottom of the endplates is perfectly flat. I sprayed the print area with Dimafix to make sure there would be no warping.

The most difficult material to print is PP due to adhesion and warping issues—I used a PP foil for that. What kind of surface did you use to print your PP components? I suspect the most common PP tape could cause leakage issues if a component is printed across the seam between two strips.

All the components are already ordered, including the MYSTAT. My department’s lab doesn’t have such a device.

Good to hear the packing tape hasn’t caused any leakage issues in your case. I ended up getting a PP adhesive foil that’s originally meant for covering book covers.

Hi! Thanks @kirk for that info. I still don't have all the components to start assembling the cell. I'll figure out how it will go and eventually reprint the jig.

Hi! I already have all the components. I had the brass plates CNC-cut, and I cut the 0.1 mm silicon gasket and grafoil with a knife (I 3D printed a template for that). I noticed that the documentation hasn't yet been updated to include the new Kamoer KPK200 pumps.

@kirk, could you send a photo showing how the tubing is connected (what length should the hoses be cut to?) and what the electrical connections are?

The documentation says to cut 4 separator sheets, but then only 3 are to be used. So is the 4th one not needed?

Also, I assume I don't need to worry about the graphite felt appearing white in your photos? It's not, for example, actually polypropylene felt mistakenly labeled as graphite felt?

Thank you for the comprehensive answer — I think you've convinced me to go with PP

While assembling the flow cell, I noticed that the manual doesn't mention anything about the Membrane Frame. I also have doubts whether the Membrane Frame model provided on the website isn't too thin (0.8 mm) to ensure a proper seal when using 4 membranes made from 230g/m² matte photo paper. Each membrane, according to my measurements, is 0.3 mm thick — which means the total thickness is 0.4 mm greater than the Membrane Frame's thickness. I also used 0.1 mm gaskets (as specified in the Bill of Materials), so such a large difference in thickness is unlikely to be compensated.
@kirk, do I need a thicker Membrane Frame or thicker inner gaskets?

Thank you @kirk . Yes, I had already understood it from your previous message.

I’ve finished the assembly and performed a leak test using demineralised water. The first attempt failed due to leaks in both reservoirs (see photo). After that, I made a small design change and increased the 3D printer’s flow rate for the infill. The new reservoirs seem fine now.
Did you encounter this problem too? How did you solve it?

The cell itself doesn’t leak. I used a torque of 3 Nm for now, but it already looks slightly distorted. Have you considered using more bolts?

I also wanted to ask: is silicone resistant to this type of chemistry? Since it’s used for gaskets, maybe silicone tubing could be used as well?

Regarding the Arduino program: it seems there are four defined pins — In1 (pin 9), In2 (pin 8), In3 (pin 7), and In4 (pin 6) — but they don't appear to serve any purpose.

As for the main Python program — should it work with no issues once the Arduino and MYSTAT are connected to the computer?