Experimental Performance Evaluation of a High Temperature PEM Fuel Cell at Different Temperatures and Pressures

Abstract

The high temperature proton exchange membranes (HT-PEM) attract growing interests due to its enhanced electrochemical kinetics, simplified pinch technology and utilization of higher CO-rich reformed hydrogen as the fuel. From the technological point of view, using pure hydrogen as fuel seems highly restrictive because hydrogen with high purity may not always be readily available. As an attractive alternative to compressed hydrogen, it is preferred to use hydrogen-rich gases as fuel. On-site generation of hydrogen using reformed fuels can be directly fed to the high temperature proton exchange membrane fuel cells (HT-PEMFCs) without first preheating the cell with external heat source to raise the temperature to its operating temperature. Since the HT-PEMFCs performance depends strongly on temperature, the cell temperature plays an important role in its operation. The purpose of this research is to experimentally study a high temperature PEM fuel cell at steady operating conditions. In this work, the performance of the fuel cell has been experimentally examined to unravel the steady-state effects of changes in temperature and pressure at a fixed hydrogen stoichiometry and variable air stiochiometries In particular, the effects that changes in temperature and pressure have on the voltage-current characteristics. Experimental data of this type is needed to develop and validate the fuel cell models, and to help understand and optimize the operation of these devices. In this study, a cell with an active cell area of 45 cm2 based on polybenzimidazole (PBI), doped with phosphoric acid is examined over the entire temperature range of 120°C–180°C with hydrogen of 99.999% purity. The quantitative results obtained from the experiments showed variations in current-voltage characteristics at different pressure and temperatures. The results will be used as a baseline value to under-study the performance of a high temperature PEM fuel cell in terms of current-voltage characteristics, when fueled with a reformate with higher CO concentrations in our future study.

Regression Analysis of High Temperature PBI Based PEMFC Performance

“…Hence, equation ( 3) is one of the multiple regression models we may recommend for use in the description of the dependence of the yield V from all the predictors, together with the model (1), irrespective of the fact that some non-significant components are included in it. The above discussed models do indicate a positive dependence of V on the temperature factor T, the increase of the temperature by 1 o C will increase on the average, the yield by 0.981 mV for model (3) and by 0.962 mV in model (1).…”

Dynamic modeling and experimental investigation of a high temperature PEM fuel cell stack

“…During operation, voltage and current are the two most important parameters one must know to evaluate the performance of a fuel cell. Increasing temperature tends to improve the performance of the fuel cell as it overcomes activation polarization, but higher temperatures also accelerate degradation processes, as presented in [18,19]. In parallel with the experimental data, models have been developed to study the phenomena of interest such as the influence of the charge double layer [20], or the distribution of current and gases in the flow channels [21].…”

A-3D-Modeling and Experimental Validation of a High Temperature PBI based PEMFC

“…They operate at higher temperatures from 120-180 o C and exhibit stable voltage output at steady state conditions. The HT-PEMFC is credited with faster electrochemical kinetics, improved water management and carbon monoxide tolerance, J. Zhang et al (1), E. Ubong et al (2) and S. Das et al(3). As a result of the low electro-osmotic drag and the good proton conductivity of the PBI membrane, the fuel cell design and the routine maintenance could also be significantly simplified, J.T.…”

“…The ease of using high temperature fuel cells operating above 140 o C currently receives wide attention because light hydrocarbon fuels (alcohol, natural gas, propane) are viewed as future candidates for PEMFC application. E. Ubong et al (2) conducted an experimental work on HT-PEMF and evaluated the polarization and power density curves as a function of temperature, pressure and air stoichiometry. S. Das et al(3) reported on a 2-5% CO mixture in hydrogen with a BASF HT-PEM membrane.…”