Sequential Stress Testing to Predict Photovoltaic Module Durability

The challenge to the PV industry is to find test methods which assess the durability of modules and their components to multiple stresses. The effectiveness of these methods can be assessed by comparison to known degradation modes observed in the field. We have developed sequential test methods which apply an accelerated exposure of a key environmental stress including UV, temperature, humidity, and mechanical stress in a sequential fashion. These stresses are applied sequentially to address the need for using established environmental equipment and methods. This methodology has been effective in predicting backsheet failures in the field and examples will be provided. Efforts to reduce the total test time will also be discussed.