Numerical investigation of the permeability level of ceramic bipolar, plates for polymer electrolyte fuel cells

Abstract

In this paper, a three dimensional, mathematical model for the analysis of the mass transfer of fuel (H-2) and oxidizer (O-2) in a polymer electrolyte fuel cell (PEFC) with solid, porous bipolar plates was developed using a commercial computational fluid dynamics code, Fluent((R)) 6.3.26 and a CAD system CATIA((R)). Simulations were carried out for various permeabilities from le m(2) to 10(-12) m(2) in the porous ceramic materials of the bipolar plates. By using a porous medium with a low permeability in the bipolar plates, it was possible to attain a higher and well-distributed current density compared to cases with a permeability of zero due to enhancement of the reaction area accessible by gas reactants. However, with an increase of permeability in bipolar plates from 10(-13) m(2) to 10(-9) m(2), the average current density decreased from 0.8497 A/cm(2) to 0.8073 A/cm(2) due to leakage of gas reactants. Consequently, an optimal permeability of bipolar plates was obtained as 4.51x10(-9) m(2) from the standpoints of leakage and distribution of gas reactants.