Optimizing temperature distribution in a PEMFC stack: A computational study on cooling plate and coolant dynamics

The performances, even the lifespan, of an actual PEMFC stack are seriously influenced by the significant temperature gradient in the single PEMFC and the temperature inhomogeneity among different units of PEMFC. To obtain better temperature distribution within the PEMFC stack, the cooling plate configuration of PEMFC and the manifold height of the stack have been optimized based on the impacts of configuration structure and the coolant dynamics in the present article upon validated models. The study found that the coolant rate increase made the temperature more consistent across the cooling plate's surface and the membrane. Except for the cooling plates with a single serpentine channel, the other five designs achieved their lowest level of temperature inconsistency at a cell pressure drop of less than 800. The mixed serpentine channel (V–I) design showed the best consistency. As the electric current in the stack goes up, the heat increases, which approximates exponential growth, and the increase in current density enlarges the temperature difference between the membrane and the cooling plate. Among the six cooling plate designs, the V–I cooling plate showed the most consistent temperature distribution, which is good for the fuel cell stack's lifespan. When the manifold height decreases, the coolant speed in all manifolds increases. A higher manifold height leads to a more noticeable improvement in cell consistency. The impact of the variation between single cooling plates is more evident at low cooling water flow rates. Among all the channels in the cooling plate designs, stacks under the single serpentine design showed the lowest variations at a constant pressure drop. Conversely, the V–I design showed the best consistency at lower operating pressures.