Module Encapsulation Materials for Thermal Cycling Resistance: A Comparative Study of Ethylene-Vinyl-Acetate and Polyolefin Elastomer Formulations

Abstract

Module encapsulant selection materially affects thermal cycling resistance, ultraviolet stability, and long-term moisture-ingress behavior. Conventional ethylene-vinyl-acetate (EVA) encapsulants have been progressively challenged by polyolefin elastomer (POE) formulations that promise improved hydrolysis resistance and reduced potential-induced degradation susceptibility. This study presents accelerated thermal-cycling test results across three EVA grades and three POE grades over 600 cycles between negative 40 degrees Celsius and positive 85 degrees Celsius, with finite-element modeling of thermomechanical stress at solder-joint and busbar-encapsulant interfaces. We identify the failure-mode transitions associated with each material class and recommend protocol refinements for encapsulant qualification within the IEC 61215 framework.