Rapid PID-Test for Unlaminated Solar Cells

Abstract

Potential induced degradation (PID) may cause significant performance losses of solar power plants. The high electric potential difference between the encapsulated solar cells and the outer module construction leads to leakage currents with the result of extensive microscopic shunting of the solar cells. Since the vulnerability of the cells to this damaging effect strongly depends on specific product properties and the manufacturing process, preventing PID on cell-level has become an important part of quality assurance. Up to now, PID-testing is predominately done after module assembly with a typical feedback loop of 96–336 h. We developed a new PID test method for unlaminated solar cells which provides equivalent test results in less than 24 h. In this work, the test parameters of the rapid PID-test for unlaminated solar cells have been evaluated and compared to a conventional module PID-test. It was found, that the new rapid PID-test for unlaminated cells is based on the same effect mechanism and the degradation speed can be increased considerably by adjusting the test conditions without losing the qualitative alignment with the conventional module PID-test.