Study on Degradation Pattern of Silicon Crystalline Solar Modules by Using Electroluminescent Technology

• Main Authors: Chen, Li-Wei, 陳立偉
• Other Authors: K. Lin
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/41431267722035988964

碩士 === 南台科技大學 === 能源工程研究所 === 99 === Due to the rapid development of the solar industry, it is necessary to develop quick measurement technology for photovoltaic (PV) modules. Electroluminescent (EL) technology can be used to inspect invisible cracks on solar cells in order to understand its relation with the aging process of the PV modules. In this experiment 60Sn40Pb (SP) and 62Sn36Pb2Ag (SPA) solders were used and the soldering was conducted under hot air 400~600°C. After the thermal cycling test (TC) and damp heat test , IV curves were measured to understand the influences of soldering parameters on the power loss of the PV modules, the efficiency of solar modules after the aging test is also discussed to understand the decline behaviors of the PV modules. After the aging test, over-soldering and damages on the solar cells can be observed in EL images. It is found that the cell damages occurred mainly during the soldering and encapsulation processes. These damages account for more than 70% of the whole damages. Statistic data show that the damage rate of PV modules increases along with the rising soldering temperature. The damages of specimens soldered with SPA solder are generally less than those soldered with SP solder. When the number of the TC test increased, the damages on solar cell also increased. The cracks will expand from the center of the cell outwardly. The break on the center of the cell caused the interruption of the electric current, which led to the decrease of the efficiency. This can be observed in the shadow of the El images. Even though the efficiency dropped obviously, the poor contact of the wires could cause the efficiency decreased. Metallographical observation of the cross section of the cells showed cracks when on specimens soldered with SP solder under 400~500°C. The soldering results of SPA specimens under 500°C are obviously better than the SP specimens.