Coupled thermo–electrochemical performance of proton exchange membrane fuel cells with micro-encapsulated phase change material suspension: A 3D multiphysics simulation study

Abstract

Efficient thermal management is crucial for maintaining the durability and electrochemical stability of proton exchange membrane fuel cells (PEMFCs). A three-dimensional (3D) multiphysics model was developed to investigate the coupled heat–fluid–electrochemical behavior of PEMFCs using a micro-encapsulated phase change material suspension (MePCS) as coolant. The effects of micro-encapsulated phase change material (MePCM) volume fraction (${\phi }_v$), coolant velocity ($V_{\text{coolant}}$), and inlet temperature ($T_{in}$) on thermal and electrochemical performance were systematically analyzed. Results show that incorporating MePCS effectively enhances temperature uniformity and suppresses local overheating. Compared with pure water, the maximum membrane temperature difference ($\Delta T_{max}$) and temperature uniformity index (TUI) decreased by 68.2% and 42.3%, respectively. The optimal operating parameters were identified as ${\phi }_v$ = 15%, $V_{\text{coolant}}$ = 0.05 m/s, and $T_{in}$ = 340.15 K, achieving a net power density of 0.518 $W·c{m}^{-2}$. Moreover, the co-flow configuration of the reaction gas and coolant improved power density by 1.41% over counter-flow, attributed to better heat–water–gas coupling. These findings demonstrate that MePCS based coolants provide an effective approach to improving PEMFCs water and thermal uniformity and overall efficiency.