Large scale model predictions on the effect of GDL thermal conductivity and porosity on PEM fuel cell performance

Abstract

The performance of proton exchange membrane (PEM) fuel cell majorly relies on properties of gas diffusion layer (GDL) which supports heat and mass transfer across the membrane electrode assembly. A novel approach is adopted in this work to analyze the activity of GDL during fuel cell operation on a large-scale model. The model with mesh size of 1.3 million computational cells for 50 cm² active area was simulated by parallel computing technique via computer cluster. Grid independence study showed less than 5% deviation in criterion parameter as mesh size was increased to 1.8 million cells. Good approximation was achieved as model was validated with the experimental data for Pt loading of 1 mg/cm². The results showed that GDL with higher thermal conductivity prevented PEM from drying and led to improved protonic conduction. GDL with higher porosity enhanced the reaction but resulted in low output voltage which demonstrated the effect of contact resistance. In addition, the compressive force reduced the porosity under the rib regions which resulted in lower gas diffusion and heat and water accumulation.

Key findings

• ▸GDL with higher thermal conductivity prevents PEM from drying and improves protonic conduction.
• ▸GDL with higher porosity enhances reaction but results in low output voltage due to contact resistance.
• ▸Compressive force reduces porosity under rib regions, leading to lower gas diffusion and heat and water accumulation.

Keywords

Identifiers

DOI

10.5599/jese.413

Journal

Journal of Electrochemical Science and Engineering

Year

2017