Combined-Accelerated Stress Testing for Advanced Reliability Assessment of Photovoltaic Modules

A combined-accelerated stress test (C-AST) has been developed to more accurately simulate the natural environment and capture the interdependencies between various stress factors. The stress factors simulated include temperature, humidity, high fidelity ultraviolet (UV) light exposure, cyclic dynamic mechanical loading, rain spray and system voltage bias. A demonstration experiment is established in the form of a backsheet differentiation test. The test includes six 4-cell p-PERC mini-modules with 3 backsheets based on polyvinylidene fluoride, polyamide, and polyvinyl fluoride. As well as two types of polyethylene-co-vinyl-acetate (EVA), one UV blocking and one UV transparent. The experiment demonstrated C-ASTs ability to identify backsheet cracking and other failure mechanisms such as UV-induced degradation, solder bonds breakage, minor corrosion, cell cracking, some of which had been missed by conventional accelerated stress tests.