Water management is one of the most crucial issues to
drive PEM fuel cells. The challenge is enhanced in the case of micro
air-breathing proton exchange membrane fuel cells (μABFC): their
thinness and their reduced surface indeed make their hydration state fast
changing and very sensitive to the experimental conditions (temperature and
relative humidity (RH)). It can lead to strong flooding or drying out issues.
Firstly, this study highlights this sensitivity by various measurements.
Then a steady state macroscopic model for the μABFC is proposed,
focusing on the cathode, using a rather original approach for diffusion in
porous media. Finally, a literal steady state formula for the water content
is provided, and its influences on the performances of the μABFC are
explicitly proposed. The model is parameterized and compared to measures in
several atmospheric conditions.