Semiempirical Model for Determining PEM Electrolyzer Stack Characteristics

A semiempirical equation was used to represent the performance characteristics of a 20-cell proton exchange membrane electrolyzer stack. The coefficients of the equation are the exchange current densities and membrane conductivity. These coefficients were determined using experimental data and a nonlinear curve fitting method. The anode exchange current density was found to be 1.65×10−8Acm−2, the cathode exchange current density 0.09Acm−2, and the membrane conductivity 0.075Scm−1. External programmable power supplies were used to obtain the (I‐V) characteristic curve of a commercial proton exchange membrane electrolyzer. Stack current, voltage, and system temperature were monitored while 1A current steps were applied to the electrolyzer stack.