Simplified Electrical Model of an Bipolar Alkaline Electrolyzer Considering the Bubble Effect

In this work, the electrical characteristics of the classic bipolar alkaline electrolyzer are analyzed experimentally. The simplified electrical model of electrolyzer cells can be represented by three voltage components: reversible voltage, ohmic overpotential and activation overvoltage. This model represents the electrolyzer operation in steady state and can be used for sizing converters. Generally, in the literature, only one electrolytic cell of the stack is analyzed in bipolar structures. This does not evaluate the behavior of the cells included in the stack and how the interactions between the cells and the electrolyte can affect the electrical model of the electrolyzer. The experiments were carried out with a classic bipolar alkaline electrolyzer of approximately 300 W. The simplified electrical model of the electrolyzer was extracted from the experimental current-voltage (I-V) curve. In addition, the voltage components of each cell were analyzed separately.