Enhanced mechanical load testing of photovoltaic modules for cold and snowy climates

Abstract

Photovoltaic (PV) deployment is increasing rapidly and even expanding into cold and snowy climates, where harsh conditions – strong winds, heavy snowloads, sub-zero temperatures, and temperature fluctuations – pose reliability challenges for PV modules. Climate-adapted accelerated aging tests are required to evaluate and choose modules capable of withstanding such climate conditions. This study investigated the mechanical stability of PV modules featuring different designs and materials at varying temperatures. Tests were performed on materials, mini modules, and full-size modules, focusing on the impact of the encapsulant behavior at low temperatures on the mechanical stability of the solar cells and glass of the module laminates. Mini modules results showed that polyolefin-based (POE) encapsulants remain flexible at low temperatures and offer better protection against mechanical damage than ethylene vinyl acetate (EVA) encapsulants. For full-size glass/backsheet modules with busbar metallization, mechanical load (ML) testing at −40 °C, and ML at 25 °C after thermal pre-stressing, resulted in increased cell cracking compared to standard ML tests at 25 °C. In contrast, thinner multi-wire metallization or a glass/glass structure – which demonstrated enhanced structural integrity – reduced cell cracking under loads. However, glass thickness and clamping of the frameless modules limited resistance to higher pressure. These findings highlight the importance of climate-specific testing and optimized material selection and module design to ensure PV system durability in cold and snowy climates.