English Abstract

Mechanical Model and Mechanical Durability in Membrane Electrode Assembly for Polymer Electrolyte Fuel Cells

Toyota Motor Corporation, Fuel Cell Development Div., Susono, Shizuoka, Japan
Nippon Gomu Kyokaishi,(2014),87(6),236-242 General Review in Japanese

Durable and reliable fuel cell (FC) stack designs need to be manufactured at low cost for FCs to be widely commercialized. FC consists of many functional layers. Membrane electrode assemblies (MEAs) are located in the center of the FC and are the main component to affect its generating performance. The MEA is a hydrophilic multi-layer membrane that consists of a polymer electrolyte membrane (PEM) and catalyst layers (CLs) that sandwich the PEM. Mechanical properties, the mechanical failure mechanism and the mitigation methods for MEA are summarized in this article. Pinhole formation in PEM induces gas leakage through the PEM and decreases generating performance. The failure mechanism for laminated MEAs and gas diffusion layers (GDLs) must be understood to ensure the reliable design of the MEA. The MEA easily deforms under channel portions of gas flow fields, because contact pressure between the MEA and GDL is relatively low. In-plane buckling deformation of MEA under swelling is an initial stage of mechanical degradation, and crack initiation occurs after the buckling. These failures can be prevented by high contact pressure between the MEA and GDL.

Keywords: Polymer Electrolyte Fuel Cells, Polymer Electrolyte Membrane, Membrane Electrode Assembly, Mechanical Degradation