Ex-situ PEM fuel cell testing: towards visualizing gas diffusion
View Patent ↗The invention comprises novel apparatuses and testing methods for evaluating a fluid diffusion component. The apparatus includes a fluid capable of undergoing oxidation or reduction, a half-cell electrode assembly able to receive the fluid, and a change in acidity indicator in communication with the assembly. An inventive method of the invention includes the steps of passing a fluid capable of undergoing oxidation or reduction through a half-cell electrode assembly to form a sample, contacting the sample with an indicator, and detecting a change in acidity in the indicator.
1. A method of testing a fluid diffusion assembly comprising:
passing a fluid capable of undergoing oxidation or reduction through a half-cell electrode assembly to form a sample;
contacting said sample with an indicator;
observing at least one concentration gradient of said sample in said indicator;
detecting a change in acidity in said indicator; and
altering a design of said half-cell electrode assembly based on at least one result of said observing step.
2. The method of testing a fluid diffusion assembly according to claim 1 wherein said indicator comprises one of a colorimetric dye, potentiometric dye, or a fluorescent pH indicator.
3. A method for selecting a fluid permeable element for a proton exchange membrane fuel cell comprising:
(a) passing a fluid capable of undergoing oxidation or reduction through a half-cell electrode assembly to form a sample;
(b) contacting said sample with an indicator;
(c) detecting a change in acidity in said indicator;
(d) observing at least one concentration gradient of said sample in said indicator;
(e) conducting the above steps (a)-(d) on a plurality of half-cell electrode assemblies; and
(f) selecting the half-cell electrode assembly from said plurality with the most uniform concentration of said sample in said indicator.
4. The method for selecting a fluid permeable element of claim 3 wherein said detecting comprises illuminating a fluorescent pH indicator with a UV lamp.
5. The method for selecting a fluid permeable element according to claim 3 further comprising forming said half-cell electrode assembly from said plurality with the most uniform conventration of said sample in said indicator into a proton exchange membrane fuel cell.
6. The method for selecting a fluid permeable element according to claim 3 further comprising detecting an amount of electrical current generated during said passing.
7. The method for selecting a fluid permeable element according to claim 3 wherein said observing comprises seeing a change in color in said indicator, wherein said indicator comprises a colorimetric dye.
8. A method of visualizing gas diffusion comprising:
passing a fluid capable of undergoing oxidation or reduction through a half-cell electrode assembly to form a sample;
contacting said sample with an indicator;
observing at least one concentration gradient of said sample in said indicator; and
altering a design of said half-cell electrode assembly based on at least one result of said observing step.
9. The method of visualizing gas diffusion according to claim 8 further comprising incorporating said half-cell electrode into a fuel cell based on at least one result of said observing step.
10. The method of visualizing gas diffusion according to claim 8 wherein said assembly comprises a catalyst layer and further comprising submerging said catalyst layer in a solution of said indicator and said fluid, detecting a change in acidity in said solution, and comparing a concentration gradient of change in the acidity of said solution to said concentration gradient of said sample in said indicator.
11. A method of visualizing gas diffusion comprising:
passing a fluid capable of undergoing oxidation or reduction through a half-cell electrode assembly to form a sample;
contacting said sample with an indicator;
observing at least one concentration gradient of said sample in said indicator; and incorporating said half-cell electrode into a fuel cell based on at least one result of said observing step.
12. The method of visualizing gas diffusion according to claim 11 further comprising altering a design of said half-cell electrode assembly based on at least one result of said observing step.
13. The method of visualizing gas diffusion according to claim 11 wherein said assembly comprises a catalyst layer and further comprising submerging said catalyst layer in a solution of said indicator and said fluid, detecting a change in acidity in said solution, and comparing a concentration gradient of change in the acidity of said solution to said concentration gradient of said sample in said indicator.