Fabricating cell components
- 3D printing or milling
- Drilling
- Cutting
Bill of Materials
Parts
- 200 g of 3D printing feedstock
- 4 cm² of conductive felt
- 50 cm² of copper sheet
- 160 cm² of gasket sheet - Dimensions must be at least enough to cut out approx. four 6 cm x 8 cm rectangles, an A4 sheet is enough
- 100 cm² of grafoil
- A4 sheet separator sheet
- 1 meter of tubing
Tools
- 1 3-axis mill
- 1 3D printer
- 1 sheet of sandpaper
- 1 utility knife
- 1 vinyl cutter machine - or laser cutter or hand tools
Step 1: Fabricate cell bodies
These are preferably milled from solid polypropylene with a 3-axis mill. The .STEP file of the below part is found here, this is exported from the flow_cell.FCStd file.
Step 2: Print rigid cell components
Using a 3D printer loaded with chemically compatible polypropylene filament 3D printing feedstock, print two reservoirs and two flow frames.
Warning
The total combined thickess of the flow frames and (compressed) gaskets is important! There are multiple thickness options in the flow-frames folder and custom thicknesses can be genererated from the FreeCAD files. The graphite felt should be compressed to 70% of it's original thickness. The compression is fixed by the combined total thickness of the flow frame and two gaskets.
Prefer conventional machining?
You could also fabricate the flow frames parts by milling/laser cutting them from a sheet of polypropylene.
Step 3: Post-process printed parts
Remove brim, raft, support material from print (depending on printing method)
Sand down, with fine-grit sandpaper, both faces of each flow frame.
This makes two flow frames and two reservoirs.
Step 4: Cut gaskets
Note:
Cutting the gaskets is most easily done with a vinyl cutter machine, but can also be done manually with a steady hand, utility blade, and appropriately sized punches.
- Using a vinyl cutter machine, download the gasket file (as svg, dxf, or pdf) and cut a sheet of gasket material to make the following four gaskets:
This makes two pass-through gaskets and two blocking gaskets.
Step 5: Cut porous electrodes
Cut two conductive graphite felt electrodes to fit inside the flow frames using scissors or a utility knife. Our current standard test uses 2 cm² geometric area cells, so cut two squares each with a side length of 14.1 mm from a larger piece of conductive felt.
This makes two cut electrodes.
Step 6: Cut separator membrane
Cut separator sheet into four 3 cm x 3 cm squares
This produces four cut membranes
Step 7: Cut grafoil current collectors
Using a precut gasket as a guide, cut grafoil into the following shape to make grafoil current collectors.
Step 8: Cut copper current collectors
Cut copper sheet into two 5 cm by 5 cm squares to make copper current collectors.
Warning to prevent leakage
Make sure at least one orientation of the copper squares fits exactly the machined square recess in the cell bodies
Cut tubing
Cut tubing into 6 15 centimeter lengths to make cut tubing pieces