A comprehensive review of cold start in proton-exchange membrane fuel cells: Challenges, strategies, and prospects

Abstract

Hydrogen energy, a clean and efficient power source, plays a crucial role in the global transition to sustainable energy. Among various hydrogen energy technologies, proton-exchange membrane fuel cells (PEMFCs) are highly promising owing to their high-power density and low-temperature operation. However, the cold-start performance of PEMFCs under subfreezing conditions remains a significant challenge. Ice formation obstructs transport pathways, disrupts electrochemical reactions, and hinders both thermal and water management. This review provides a comprehensive analysis of recent advancements in PEMFC cold-start research, particularly on material innovations, structural design optimizations, and multi-mode cold-start control strategies. Unlike previous reviews that focus on numerical modeling, experimental analysis, thermal management, or optimization strategies, this paper integrates key mechanisms influencing cold-start performance. These mechanisms include water content regulation, heat transfer enhancement, and ice mitigation techniques. Moreover, various cold-start strategies (including purge-assisted water removal, external load regulation, and hybrid heating) are compared to assess their effectiveness and feasibility in real-world applications. Additionally, the review highlights key challenges affecting cold-start efficiency and outlines future research directions. These include the development of self-regulating hydration membranes, advanced water transport structures, and adaptive multi-phase startup strategies. This paper integrates fundamental principles with practical engineering approaches to outline a roadmap for enhancing PEMFC cold-start technology, particularly for automotive and stationary power applications.