Water‐Balance Calculations for Solid‐Polymer‐Electrolyte Fuel Cells

Abstract

The proper balance between water production and removal is particularly important for successfully operating solid‐polymer‐electrolyte fuel cells. Imbalance between production and evaporation rates can result in either flooding of the electrodes or membrane dehydration, both of which severely limit performance. We present a mathematical model of the solid‐polymer‐electrolyte fuel cell that identifies operating conditions that result in a water balance. The model is one‐dimensional and is derived from basic principles of gas‐phase transport. The mechanisms of membrane water transport are not included explicitly in the model, and the membrane is taken as uniformly wetted, which renders the model most applicable to thin membranes. We suggest how humidification of reactant gases can be adjusted as current density is varied during an experiment (at constant temperature, pressure, and reactant feed rates) in order to accommodate the fuel cell's changing demands for water. Humidification requirements of inlet reactant gases for a wide range of practical operating temperatures, pressures, and gas feed rates have been identified. The analysis also identifies conditions in which reactant transport limitations govern the behavior of the fuel cell.

Effects of porosity change of gas diffuser on performance of proton exchange membrane fuel cell

“…Bernardi [4] studied the humidification of the inlet gas that is required to maintain a water balance in a PEM fuel cell. Verbrugge and Hill [5,6] developed a one-dimensional model for the proton exchange membrane (MEA) based on the Nernst-Plank equation.…”

Macroscopic Modeling of Polymer-Electrolyte Membranes

“…In addition, a reference-potential boundary condition is often used on one side of the membrane. Finally, there are those models that treat catalyst layers as interfaces [74,97,118,139,140]. For these simulations, the membrane boundary conditions can include source terms such as reactant consumption and heat generation.…”

Global Assessment of Hydrogen Technologies – Task 5 Report Use of Fuel Cell Technology in Electric Power Generation

“…Large power station operators require an alternate fuel, usually heavy oil. Several views and suggestions from Exxon Mobil [Bernardi, 1990] are as follows.…”