The Study on the Long-term Reliability Characteristics of Ribbon Joint: Solar Cell Ribbon Thickness and Solder Compositions

In this paper, Thermal Shock tests were performed varying the composition of the solder and ribbon thickness (A-type:0.2mm/60Sn40Pb, B-type:0.25mm/60Sn40Pb, C-type:0.2 /62Sn36Ag2Pb, D-type:0.25mm/ 62Sn36Ag2Pb) for evaluating the long-term reliability about Ribbon junction of Silicon solar cells. Thermal Shock test condition was performed during the 600cycles having -40 ~85 temperature range each 15 minutes; Ai Ai One cycle time was 30min. As a result, the initial efficiency of the A-type, B-type, and C, D-type were showed 15.0%, 15.4% and 15.8% respectively. After thermal shock test, the efficiency decreasing-rate of each type were as follow that A-type was 13.8%, B-Type was 15.4%. C-Type and D-Type was 15.3% and 16.2%, respectively. Also, degradation of surface changes and I-V characteristic curves were showed that the series resistance of the A, C-type was increased. Also, current lowering starting point of C-type shown 0.05volt(v) earlier than that of A-type. And B, D-type shown characteristics of composite lowering efficiency such as increase of series resistance, decrease of parallel resistance and cell damage. Therefore Initial solderability and efficiency of