Fuel Cell System Model: Fuel Cell Stack

Abstract

The fuel cell stack model contains four interacting submodels which are the stack voltage, the anode flow, the cathode flow, and the membrane hydration models. A block diagram of the stack model is shown in Figure 3.1. A stack thermal submodel can be added in the future when temperature changes are taken into account. The electrochemical reaction happening at the membranes is assumed to occur instantaneously. In this model, the stack temperature is assumed to be constant and uniform across the stack. Because the stack temperature dynamics has a relatively long time constant as compared to the other dynamics considered in this model, we assume that the stack temperature is constant at 80°C. The voltage model contains an equation to calculate stack voltage based on fuel cell pressure, temperature, reactant gas partial pressures, and membrane humidity.