研究目的
Quantify the relative significance of the stressors including UV radiation, temperature (T), and moisture (relative humidity, %RH). Which stressors most significantly reduce attachment during weathering? What range of stressors should be applied for accelerated testing? Determine if there is significant coupling between UV, T, and %RH. What factors should be applied in an accelerated weathering test for attachment? Compare between artificial and natural weathering. What types of test methods are most appropriate (eg, steady-state or a test sequence)?
研究成果
The study identified water humidity levels as more significant than UV radiation in affecting adhesion strength. Specimen conditioning was critical, with high humidity levels leading to greater loss of adhesion strength. UV degradation contributed to the reduction in adhesion strength, confirming the need for UV weathering in accelerated testing of encapsulant adhesion. The study recommends including specimen conditioning in test methods for adhesion and exploring more complex accelerated stress tests for PV modules or mini-modules.
研究不足
The study did not account for cold temperatures and their effects on mechanical modulus and inelastic deformation. The accumulation of damage through successive time-temperature events was not examined. The relative rates of hygrometric and UV degradation between encapsulant materials were not explored. The transparent coupon specimens used in natural weathering experiments had lower daytime temperatures than PV modules, potentially underestimating UV degradation effects.
