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.