Environmental Stability of the Contact Resistivity of Interconnects Based on Electrically Conductive Adhesives and its Correlation to Photovoltaic Module Power Loss under Accelerated Aging Testing†

This study presents a detailed evaluation of electrically conductive adhesives (ECAs) in photovoltaic (PV) modules, focusing on their impact on module power loss under standard accelerated aging conditions used in industry. The study was enabled by using an innovative analytical method to determine the contact resistivity of ECA‐based interconnects that was previously developed as part of this research and provides unique insights into ECA performance in PV modules. The findings reveal that interconnects based on epoxy‐ECA formulations tested in this experiment exhibit significant degradation in contact resistivity during damp heat and thermal cycling tests, whereas interconnects using acrylic‐ECA formulations demonstrate a more stable contact resistivity. Contrary to expectations, no strong correlation was observed between the contact resistivity degradation of ECA‐based interconnects and module power loss, challenging prevailing assumptions about module reliability. This suggests that other factors, such as cell metallization degradation, play a more critical role. Furthermore, encapsulation materials significantly influence module resilience, with the polyolefin elastomer formulation used in this study providing superior moisture protection for cells, while the ethyl vinyl acetate formulation offered better protection for interconnects. These insights underscore the complexities of module reliability, highlighting the need for innovative materials and enhanced testing protocols to ensure long‐term performance.