Pressure Effect on the PEMFC Performance

Abstract

A three‐dimensional and two‐phase computational fluid dynamics (CFD) model for a single serpentine channel polymer electrolyte membrane fuel cell (PEMFC) based on ANSYS FLUENT fsimulation software is used to investigate the pressure effects on the PEMFC performance. The model is validated by a series of experiments and the numerical data fit well with the experiment results. The PEMFC performance is improved as the increase in back pressure. The simulation results revealed an important mechanism between pressure and humidity: a high back pressure could lead to a high relative humidity (RH) in cathode channel, which results in a high membrane water content. Based on this mechanism, the voltage increased by pressurization is divided into 2 parts: the voltage increased by reactants' partial pressure (Nernst potential) and the voltage increased by enhanced membrane water content. The comparison showed that the major benefit of pressurization is to keep adequate water in the membrane. The analysis of net power efficiency is also performed and it shows that the back pressure of 50 kPa is enough at low densities (less than 1,000 mA cm−2) and the back pressure of 100 kPa is needed at high densities (more than 1,000 mA cm−2).

Two parameters identification for polarization curve fitting of PEMFC based on genetic algorithm

“…The performance difference gradually decreases with elevated pressure, while the performance improvement is basically the same with the same temperature rise. This is because the ratio of pressure increase to the operating pressure is reduced and the impact on cell performance will be diminished 47 . As thus, polarization curve fitting is based on the operating conditions, which provides a basis for BOP selection and control strategy development.…”

“…This is because the ratio of pressure increase to the operating pressure is reduced and the impact on cell performance will be diminished. 47 As thus, polarization curve fitting is based on the operating conditions, which provides a basis for BOP selection and control strategy development.…”

Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and Role of Metal-Support Interactions

“…[4][5][6] Therefore, it is necessary to improve MSR technology in order to reduce heating and steam requirements and achieve a cost-efficient H2 manufacture. In this sense, the capability to operate fuel cells at ambient pressure, 7 and the development of hydrogenselective membrane reactors, [8][9][10] represent an opportunity to increase the thermodynamically limited conversion imposed by the endothermicity of the MSR reaction, 11 allowing both lower operating temperatures (500-600 °C) and lower steam-to-methane ratios, while maintaining good H2 yield. Commercial catalysts in industrial reforming units, typically consisting of nickel on magnesium or aluminum oxides supports, are designed to withstand high-temperature operation without losing strength, and thus prioritize stability and thermal resistance over surface area.…”

Non-Dimensional Analysis of Diffusion Characteristics in Polymer Electrolyte Membrane Fuel Cells with Mismatched Anodic and Cathodic Flow Channels

“…Rohendi et al [12] confirmed that when the performance of the membrane electrode assembly (MEA) was degraded after an operating time of 100 h followed by the application of backpressure, the cell conductivity was improved, and the open circuit voltage (OCV) was maintained compared with that under ambient conditions. Lu et al [13] applied a 3D computational fluid dynamics (CFD) model to inspect the effect of pressure on the PEMFC performance and found that high backpressure leads to high relative humidity in the cathode channel, which contributes to high membrane water content.…”