A TRADITIONAL LITERATURE REVIEW ON MODELING AND OPTIMIZATION OF SHUNT CURRENT REDUCTION IN LARGE-SCALE ALKALINE ELECTROLYZER (AEL) STACKS

Abstract

Shunt currents represent a major parasitic loss mechanism in large-scale alkaline electrolyzer (AEL) stacks, adversely affecting electrical efficiency, current uniformity, component durability, and operational safety. As alkaline water electrolysis continues to play a critical role in large-scale hydrogen production, particularly in renewable energy–integrated systems, the mitigation of shunt currents has emerged as a key challenge in stack design and optimization. This traditional literature review systematically synthesizes existing research on the mechanisms, modeling approaches, and optimization strategies associated with shunt current reduction in large-scale AEL stacks, with a strong emphasis on numerical and multiphysics simulation methods. A comprehensive literature search was conducted in accordance with the PRISMA framework across major scientific databases, resulting in the selection of 56 peer-reviewed studies published between 2010 and 2025. The reviewed literature encompasses analytical models, numerical simulations, and fully coupled multiphysics approaches used to analyze current distribution, electrolyte conduction pathways, and stack-level electrical behavior. Particular attention is given to studies employing COMSOL Multiphysics, which has emerged as a widely adopted platform for simulating electrochemical, electrical, thermal, and fluid dynamic interactions within alkaline electrolyzer stacks. The findings indicate that shunt current magnitude is strongly influenced by stack geometry, manifold configuration, electrolyte conductivity, material properties, and operating conditions. Simulation-driven optimization strategies, including geometric redesign, electrical insulation, and flow-field modification, demonstrate significant potential for reducing parasitic current losses while maintaining hydrogen production efficiency. However, the literature reveals persistent gaps in large-scale experimental validation, standardized modeling practices, and integrated optimization frameworks. This review identifies key research trends, methodological limitations, and future research directions aimed at improving the efficiency, scalability, and long-term reliability of large-scale alkaline electrolyzer systems.