Test-to-failure of PV modules: Hotspot testing

The primary goal in the qualification testing is to identify the short-term reliability issues in the field. The primary goal in the accelerated reliability or lifetime testing is to identify the initial, operational and ultimate reliability issues in the field so that the lifetime can be predicted and warranty can be protected. The test-to-failure (TTF) testing is a compromise and it falls between these two extremes of qualification testing and lifetime/reliability testing. One of the major reliability issues of photovoltaic modules in the field is the hotspot endurance. A TTF study involving hotspot stress along with thermal cycling stress is undertaken and is presented in this paper.