Thermal and water transfer in PEMFCs: Investigating the role of the microporous layer

The objective of this work was to investigate experimentally the effects of the microporous layer (MPL) within a PEMFC. The experiments consisted in measuring, at the anode and at the cathode, the average temperature of the electrodes using small platinum wires, heat fluxes using heat flux sensors and water fluxes by means of water balance for two builds of cell; one with porous layers and MPL and another without MPL. Three thermal configurations related to the imposed temperature of the plates were studied. The measurements put forward a new role of the microporous layer on heat transfer. Indeed, the MPL implies an increase of the electrodes temperature by adding a thermal resistance. This higher temperature enables to avoid the saturation at the electrodes and improve the water removal towards the flow field plates. In addition, the effective thermal conductivity of microporous layer, a key parameter for the analysis of heat transfer in the fuel cell, was estimated in situ.