Investigation of the Distribution of the Mass Transport and Reaction　Rates in a Fuel Cell By the Integrated Fuel Cell System Simulator Including the Dynamics of Air, H₂, and Cooling Systems

Abstract

A 1+1D model to estimate the distribution of the mass transport and reaction rates in the through-plane and along-channel directions in a fuel cell (FC) was developed. The developed model was integrated to the FC system model and controllers which reproduce the dynamics of the 2nd-generation MIRAI, state-of-the-art fuel cell electric vehicle (FCEV). The dynamic behavior of the distribution of mass transport and reaction rates are investigated in low to high load and temperature conditions with the integrated simulator. It was shown that the H2O recirculation from the cathode outlet to inlet region inside the cell through the anode channel played an important role to the determination of the distribution. It was unique feature with the FC system without a humidifier in the air system and the counter-flow configuration of a fuel cell. The impacts of the specification of the controller in the H2 and air system on the overall system performance and the dynamic behavior of the distribution in a fuel cell. The increase of the anode inlet flowrate and cathode inlet pressure enhanced the H2O recirculation in the cell and improved the intensively nonuniform distribution of the humidity, which can cause the acceleration of mechanical degradation of the MEA. The tradeoff of the change of the controller specifications were assessed. It was demonstrated that the relationships among the specification of the controller, the overall system performance, and the dynamic behavior of the distribution in a fuel cell can be evaluated quantitatively.