Critical Factors Contributing to Thermally Induced Hotspots in PEM Water Electrolysers

Thermally induced hotspots in proton exchange membrane water electrolysers (PEMWEs) pose significant challenges to the efficient production of green hydrogen. This literature review explores the key factors contributing to hotspot formation, including bubble behaviour, water starvation, current density distribution, and temperature gradients within the electrolyser. Bubbles generated at the catalyst layer impede mass transport, leading to uneven current density distribution and localised overheating. Water starvation, often caused by insufficient water supply or inefficient water management, exacerbates this issue, promoting dry regions that further intensify temperature disparities. The non-uniformity in current density, influenced by variations in material properties and operating conditions, results in uneven thermal distribution across the cell, with hotspots forming in areas of lower resistance. Moreover, material surface characteristics such as the hydrophobicity of the porous transport layer, the porosity of the catalyst layer, and the thermal conductivity of the bipolar plates play a pivotal role in regulating water flow, heat dissipation, and bubble detachment. Understanding these interconnected factors is essential for optimising the design and operation of PEMWEs to enhance thermal management and minimise hotspot formation, thereby improving overall efficiency and stability for sustainable hydrogen production.