Designing the large-format cell
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@Vorg First we will make sure the design doesn't leak with current silicone gaskets. Once we have that I can send you a message and we can talk a bit more about how it would work with a silicone sealant.
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@Vorg First we will make sure the design doesn't leak with current silicone gaskets. Once we have that I can send you a message and we can talk a bit more about how it would work with a silicone sealant.
@danielfp248 yes, except vorg is another user
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@danielfp248 yes, except vorg is another user
@DDM Lol, sorry, I will message you both.
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I also just got birchwood endplates for the first test of the large scale design. These are 1.8cm thick, so stiff enough to be able to seal the cell in theory. Since there is no chemical contact with the endplate, we shouldn't have any problem using this material. I will get brass current collectors next week - Xometry just shipped them to me - and will then proceed with the first test.
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@danielfp248 congrats! Is this plywood and is there any reason you could not manufacture this using regular woodworking tools, like a table saw and drill press? (Which I fortunately have at home
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@danielfp248 congrats! Is this plywood and is there any reason you could not manufacture this using regular woodworking tools, like a table saw and drill press? (Which I fortunately have at home
@sepi It is not plywood it is birchwood (people who did the laser cutting didn't have plywood). You can manufacture this with normal wood working tools, I don't have any so it was just easier to order it. Important thing is that hole locations are correct and the wood be very flat. You definitely need a planer to achieve that.
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If it's solid wood, there is a high chance that it will warp with changes in temperature and/or humidity. I guess it is some kind of plywood made from birch wood. Plywood is much less prone to warping due to the aforementionned external factors. In the end things might be different since the plates will be under pressure. I'm wondering if a structure a bit similar to what you did for the PLA endplates in the small battery might work. That's off course only if you run into trouble with your current, simple design.
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I just put together the first large scale cell and did a test with tap water recirculation to test if the geometry would work with no leaks. I didn't use any grafoil but just the bare brass current collectors, since I'm not doing any electrochemical testing right now.
There was a significant leak from one of the input ports as the pressure required to flow through the flow frame geometry was too high, but there were no leaks through the gaskets. We are going to be modifying the flow frame geometry to be the simplest possible, similar to the small scale kit. This way we can make sure we have a design that can flow at the lowest possible pressure and then we can scale complexity as required later on to improve shunt currents. We might also add barbs to the input ports to prevent this sort of leaking. We'll keep you posted on our progress!
Also, the wood did not warp on compression!
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I'm 99% sure this is not possible, but maybe tossing it out there would give someone an idea for another direction to look. This problem of a shunt current makes my envision some sort of FET like object with a passage between source and drain to allow fluid to flow through it while a "gate voltage" pinches off current flow through it.
I know, crazy, but maybe now that it's out there, the thought will stop bouncing around in my head
