Fuel cells have unique technological attributes: efficiency, absence of moving parts and low emissions. The Direct Methanol Fuel Cell (DMFC) has attracted much attention due to its potential applications as a power source for transportation and portable electronic devices. With the advance of micromachining technologies, miniaturisation of power sources became one of the trends of evolution of research in this area. Based on the advantages of the scaling laws, miniaturisation promises higher efficiency and performance of power generating devices, so, MicroDMFC is an emergent technology. Models play an important role in fuel cell development since they facilitate a better understanding of parameters affecting the performance of fuel cells.
In this work, a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in a fuel cell, already developed and validated for DMFC in [1-3], is used to predict Micro DMFC performance. The model takes in account all relevant phenomena occurring in a DMFC. Polarisation curves predicted by the model are compared with experimental data existing in literature and the model shows good agreement, mainly for lower current densities. The model is used to predict some important parameters to analyse fuel cell performance, such as water transport coefficient and leakage current density. This easily to implement simplified model is suitable for use in real-time MicroDMFC simulations.
The model adjusts well experimental data for low current density values. The most significant discrepancies between the model and experimental data are for conditions near the limiting current densities due to the fact that the model neglects two-phase flow effects. Parameters simulated by the model are very useful to explain fuel cell performance and allows choosing better fuel cell operating conditions. The presented model can be a useful tool to improve micro DMFC understanding and to optimise fuel cell design. The model can be used in real-time system level microDMFC calculations.