Systemic modeling and analysis of DMFC stack for behavior prediction in system-level application

In this paper, a systemic model based on the equivalent circuit modeling method is developed in order to analyze the electrical behavior of direct methanol fuel cell (DMFC) stack in complex systems. The systemic model consists of the polarization curve subsystem, the long time discharge subsystem, and the temperature distribution of catalyst layer subsystem. The effect of various operating parameters on the behavior of the DMFC stack is evaluated by the systemic model. In addition, the systemic model is applied to design a DMFC stack with 4 single DMFCs connected in series. The simulated current-power profiles and time-power profiles are validated by the experimental results of the designed DMFC stack. Numerical results such as the effect of assembly pressure and the temperature distribution of catalyst layer are also discussed. Based on the numerical results, the most appropriate assembly pressure for the DMFC stack is 1.5 MPa. The total energy released at the current of 400 mA is the maximum according to both the simulated and experimental results. This systemic model provides a meaningful method to design DMFC stacks in the view of the system-level.