Load Following Characteristics of Phosphoric Acid Fuel Cells

Abstract

Experimental studies and theoretical considerations are presented on load following characteristics of phosphoric acid fuel cells.
During the transient period in which load increases and required fuel is supplied to cells after a few seconds delay, pressure change, cell voltage, load current and current distribution of the cells are measured using potential lead equipped on large scale cells. As the delay time of the fuel supply increases, generating capability of the cells decreases simultaneously with pressure drop saturation of the stack. These phenomena can be explained by accumulation of inert gas in the cells, which obstructs hydrogen supply to them. Higher hydrogen concentration in the fuel and lower fuel utilization previous to load change are effective measures to allow generation with a longer fuel supply delay, but load ratio previous to load change has no effect.