A Simplified Test Station for Alkaline Fuel Cell

Abstract

For most of the last four decades, the alkaline fuel cell (AFC) has been largely overlooked in favor of the polymer electrolyte membrane fuel cell (PEMFC) and the solid oxide fuel cell (SOFC). However, the persistently high costs and complexities of the PEMFC and the SOFC have led to renewed interest in the AFC in recent times. This work reports the designs of custom test fixtures and electronics instrumentation relevant for AFC electrode testing and system optimization. Features implemented in the designs include a real-time voltage measurement unit (VMU), electronic load circuit, and electrolyte heater system. Validation experiments indicated a close agreement between the VMU’s readings, Nernst equation predictions, and readings from a digital voltmeter. The electrolyte heater system’s temperature measurement module was validated with its ability to replicate a cooling profile of ethanol similar to that obtained from a mercury-in-glass thermometer. Materials selection, design considerations, and fabrication steps for other test station components, such as the button-cell test apparatus and the half-cylinder electrolyte heater, were presented. The test station was used for polarization studies of aluminum-air AFC under different conditions of potassium hydroxide (KOH) electrolyte temperature and concentration. The studies revealed optimum values of electrolyte temperature and concentration for the AFC electrode to be 70 °C and 4 M KOH, respectively.