Consistency and Uniformity of Contact Pressure of PEMFC Stacks Under Nonuniform Temperature Field and Strip Clamping

ABSTRACT

In proton exchange membrane fuel cell (PEMFC) stacks, the gas diffusion layer (GDL) contact pressure is one of the key factors influencing the operation efficiency, governed jointly by assembly loading and operating‐temperature gradients. This study couples a heat transfer model with a thermo‐mechanical finite‐element model to quantify GDL contact pressure under room‐temperature assembly, uniform high/low temperature loads, and a mapped nonuniform operating‐temperature field. Unlike a uniform thermal load, the mapped field produces asymmetric thermal expansion and a pronounced redistribution of contact pressure: the coefficient of variation increases to 0.337, compared with 0.118 at room temperature, whereas the pressure range broadens to 0.45–2.19 MPa. These results show that a uniform‐temperature assumption can preserve the overall spatial consistency while missing localized over‐compression and under‐compression. This mechanical heterogeneity may contribute to nonuniform interfacial electrical contact and mass‐transfer conditions. The model therefore provides a mechanical basis for considering spatial temperature gradients when selecting clamping loads and assessing contact‐pressure margins. Its direct effects on electrochemical performance and sealing leakage require further electrochemical and leakage measurements.