Water molecules accelerate the degradation of silicon heterojunction solar cells: A review

Abstract Reliability evaluation of heterojunction photovoltaic modules, with an emphasis on damp‐heat testing, serves as a critical prerequisite for guaranteeing long‐term high‐efficiency power output and supporting successful commercial deployment. This paper discusses the degradation pathways and protective strategies for silicon heterojunction (SHJ) solar cells under the moisture exposure. Numerous damp‐heat aging experiments have shown that environmental moisture infiltration significantly exacerbates the degradation kinetic process of SHJ solar cells, wherein water molecule driven ion migration proves particularly detrimental to the interfacial properties of the devices. At the module level, moisture ingress induces hydrolytic degradation of encapsulation materials, resulting in interfacial delamination, optical discoloration (yellowing), encapsulation failure, and electrode electrochemical corrosion. These effects contribute to a substantial decline in the power output of the module. In view of the aforementioned failure mechanisms, this paper comprehensively reviews the current mainstream solutions: optimization of the encapsulation structure, including the development of novel high‐barrier encapsulation films and advanced edge sealing technologies to enhance module weatherability; innovative cell design, such as the introduction of front surface barrier coating and passivation film stacks to improve the intrinsic stability. This review highlights the critical role of enhancing material weatherability and reinforcing interfacial barriers, aiming to provide insights for developing cost‐effective high‐stability solutions to facilitate the large‐scale application of photovoltaic technology across diverse environments.