Etim U. Ubong

Analysis of Cell to Cell Voltage Variations in a 4-cell and 25- Cell Low Temperature PEM Stacks

An experimental study of cell to cell voltage variations on two different low temperature (LT) PEM stacks is presented. One is a‐4 cell‐membrane‐humidified stack. The second is a‐25 cell stack with an external humidifier. The test results taken from open circuit voltage to full load reveal that in both stacks, the first cell almost always produced the least voltage. Further tests at additional two levels of air stoichiometry (Sair) with the 4‐cell stack confirmed the previous observations. An analysis is conducted to unravel the influence of various factors on cell to cell voltage variations. Limitations of this investigation are noted and future work is suggested.

Regeneration of Pt Electrode Activity in H

An investigation has been made on a high temperature polybenzimidazole (PBI) proton exchange membrane doped with phosphoric acid. Two and five percent concentrations of CO in the hydrogen were evaluated to determine the effect of high CO concentrations on the performance of the PBI membrane under conditions that are representative of reformed fuels. A 3 × 3 matrix of fuel composition, temperature and air stoichiometry was studied at two pressures: one atmosphere and one bar gage. A controlled experiment using hydrogen of 99.997% purity was used as a baseline fuel before and after the exposure to higher CO concentrations. A comparison between the pure hydrogen runs and those where CO was also present in the fuel showed a significant reduction in cell performance. Subsequent runs with pure hydrogen restored the cell performance. The mechanism that led to the cell recovery with pure hydrogen will be discussed.Copyright

Regulations Governing Transportation of Portable Fuel Cell Devices and Systems in Aircrafts

The revolutionary advancements of electrical fuel cell power within the past decade has drawn public awareness and criticism to the hazardous nature of hydrogen and other fuels used in fuel cell powered devices and systems. Although these fuels are regulated, their fuel storage devices (cartridges) are not, hence, requiring various governmental agencies approval such as the Department of Transportation, which typically applies its regulations for transportation of hazardous materials. As the development of these devices grow, issues regarding transportation of hazardous materials, components in mass transportation systems: e.g. passenger aircrafts, ships, trains, and buses, USPS, will come under intense legal scrutiny. The United States and other nations, including international bodies such as the United Nations have national and international laws regulating transit of hazardous/toxic materials across state/national and international boundaries. These different regulations often conflict and are serious barriers to the transportation of fuel cell powered consumer electronic devices such as laptop computers, cell phones, camcorders, calculators and even portable CD Players in commerce. This report addresses the regulatory framework regarding transportation of fuel cell hazardous-material – containing devices by aircrafts and suggests solutions to obtaining approval from various governmental agencies.Copyright