NEW ACCELERATION TESTING METHOD 'HIGHLY ACCELERATED THERMAL CYCLING TEST' : ACCELERATION METHOD THROUGH DEGRADATION MODE ANALYSIS

摘要

A new acceleration testing method "Highly Accelerated Thermal Cycling (HATC) test" has been developed in order to evaluate the long-term reliability of PV modules with shorter test period than normal thermal cycling test of IEC61215. For further degradation acceleration, the temperature difference (ΔT) dependence of the degradation for thermal cycling test was examined and verified. The ΔT conditions were 165°C (HATC), 125°C (IEC TC) and 90°C respectively. The results show that the degradation was accelerated under larger AT condition. The dominant degradation mode caused by both HATC and IEC TC was same, which is the increase in series resistance due to solder bonds degradation of interconnector. The Eyring model was employed to estimate the acceleration factor (α) of HATC (ΔT=165°C) compared to normal IEC TC (ΔT=125°C) showing approximately a difference of 2.3 times, which means the degradation of HATC 200 cycles is equivalent to the normal IEC TC 460 cycles. The experimental results are reported mainly focusing on the change of photo/dark Ⅳ using Ⅳ analysis technique.