Thermal management of polymer electrolyte membrane fuel cells: A critical review of heat transfer mechanisms, cooling approaches, and advanced cooling techniques analysis

Thermal management plays a crucial role in enhancing the efficiency and durability of polymer electrolyte membrane fuel cells (PEMFCs). Cooling PEMFCs can be challenging due to the small temperature differences between the stack and the ambient. In this paper, the heat transfer mechanisms and primary cooling techniques available for PEMFCs are comprehensively reviewed. It is found that applying proper cooling methods/thermal management strategies can add significant values to a fuel cell system in terms of size, costs, and overall performance. Remarkably, a thermal resistance network involving the heat transfer process in PEMFC systems is developed. Adopting new advanced cooling techniques, such as the liquid metal technique, graphene-based radiator with ultra-high thermal conductivity, radiative cooling, and enhanced airflow conditions, can help reduce the thermal resistance between the liquid-cooled stack and the radiator. Furthermore, to address the issue of a bulky radiator for a fuel cell vehicle and because a large amount of water will be generated during the operations of fuel cells, some novel cooling techniques using the latent heat obtained from the vaporization of water, i.e. the evaporative cooling system and spray cooling system, are proposed and discussed. This paper aimed to identify the research gaps in this area and offered a new direction for developing a compact PEMFC cooling system.