Nanoscale simulation of ice melting behavior and thermal conductivity characteristics of catalyst layers in proton exchange membrane fuel cells using the lattice Boltzmann method

• A enthalpy-based LB model is developed to study the ice melting process within the catalyst layer. • The Pt/C mass ratio influences the temperature distribution and ice melting rate in catalyst layer. • Lower content slows the ice melting due to reduced heat transfer efficiency. The cold start issue of fuel cells is critical due to the risk of ice formation within the catalyst layer at low temperatures, posing significant challenges to efficient operation and requiring effective thermal management strategies. In this paper, the ice melting process in the catalyst layer is simulated using the enthalpy-based lattice Boltzmann method (LBM). Catalyst layer structures with varying Pt/C mass ratios, ionomer contents, and carbon sphere radius are generated through random reconstruction. The effects of these parameters on heat transfer efficiency and ice melting speed are analyzed. The results indicate that higher Pt/C mass ratios, higher ionomer contents, and smaller carbon sphere radius are found to significantly enhance heat transfer performance and ice melt rates. Conversely, lower Pt/C mass ratios, lower ionomer contents, and larger carbon sphere radius are observed to delay the melting process. It is suggested that a balanced approach to Pt/C mass ratio, ionomer content, and carbon sphere radius is considered in the design of the catalyst layer to optimize cold start performance and thermal management efficiency of fuel cells. This study delves deeply into the key factors of fuel cell cold start and provides theoretical support for its performance optimization.