I am trying to build pressure on the anode side; however, I noticed that there is a small gas flow from the cathode side. Pressure does build up when I close off the cathode side, so I was wondering if I need to regulate the pressure on the cathode side as well or is there a hole in the MEA?
There should be no gas flow between anode and cathode side, but you will always have finite leak rates. Still there should be a remarkable pressure difference between both sides when pressurizing one side. Can you provide me with some more details of the cell setup and your measured leakage rate?
There seem to be some misunderstanding. "Flow from the cathode side" means you observe a gas flow from cathode to anode. Is that correct? This would indicate a higher pressure on the cathode side in comparison to the anode.
But analysis is difficult, as Sebastian mentioned. We need information about your setup etc.
Have you checked your test bench with anode and cathode side for leakages without any MEA setup in between? This would be first step to make sure that your test bench has no leakages.
And please keep in mind that pressure differences between anode and cathode across a MEA should not be high, we check our systems with approx. 300 mbar pressure difference only.
In general, a certain hydrogen crossover from anode to cathode is not uncommon in FC operation, but the H2 crossover rate should be very low. Crossover current can be determined. A sudden drastic increase in crossover current usually means that a pinhole in the membrane exists.
Thank you for your help! Yes, I observe a small flow on the cathode side when I am only flowing N2 on the anode side. My cell must be leaking somewhere but it isn't through the MEA since the linear sweep voltammetry looks good.
If you will properly fix your gasket above the flow field channel ,then there will be no chance of gas leaking. The thickness of MEA, membrane should be considered during choosing the thickness of gasket.
If all the things are right and again gas is coming from one side to other, then there might be a pinhole in membrane.
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