Damp Heat Test and Thermal Cycling Test for Solar Modules

… more less The damp heat test and the thermal cycling test are two standard stress tests that commercial solar modules must pass. In damp heat, the module sits in a chamber at 85 °C and 85 percent relative humidity for 1000 hours, about six weeks. This pushes water through the package while heat speeds up every reaction. It mainly tests the edge seal and the encapsulant. In thermal cycling, the chamber swings between about minus 40 °C and plus 85 °C, usually for 200 cycles. Glass, plastic and metal grow and shrink by different amounts as they warm and cool. That mismatch can peel layers apart, crack thin films and break solder joints. It mainly tests how well the layers stick together. A module usually passes if it loses less than about 5 percent of its power after each test. You read the result as a power-versus-time plot, like a T80 curve. Passing is needed, but it does not prove a 25-year life. The tests are short, and they leave out light, UV and voltage, which also harm perovskites. Look for results that combine light with heat as well. After this Concept you can describe what damp heat and thermal cycling test, read a pass or fail result, and say what a pass does not prove.