Lifetime warranty test method considering potential induced degradation recovery behavior

In recent years several failure modes of PV modules operated under high potentials were observed. Most dominant degradation mechanism is called “potential induced degradation (PID)” of crystalline PV modules [1]. PID test as proposed by the IEC working group does not reflect on particular modules. As a consequence, they do not fulfill the requirements of a lifetime warranty test [2]. Especially, it is not reflect the recovery characteristics of the solar cell. In this study we have focused on the lifetime test method considering the recovery characteristics of the n-type mono crystalline solar cell. The sensitivity of the modules regarding potential induced power degradation was investigated with respect to the recovery behavior under illumination. Positive as well as negative potential to ground was considered. The test was divided in two parts. First, a PID test was performed according to IEC TS 62804 ed. 1, method a. Then, a special PID-/ light-recovery sequence was performed.