Fabrication and Characterization of Low-Temperature Conductive Film Bonded Crystalline Silicon Solar Cells and PV Modules

Low-temperature conductive films (LT-CFs) were examined as a bonding material for fabricating a solar cell string. Morphological, mechanical, and electrical contact properties of the LT-CFs and solar cells bonded using them under various conditions were carefully evaluated. In particular, a value combining all sample bonding parameters, VBP (VBP = temperature (°C) × pressure (MPa) × time (h)), was introduced.On the basis of the results obtained, the parameter range was divided into three regimes: soft, moderate, and hard regime. The moderate regime was corresponded to strong bonding and low power loss. LT-CF-bonded cells in this regime showed a compression rate of 39.7?45.0 % corresponding to a reaction rate of 80?90 %, peeling strength of ~1 N/mm, and power loss of 1.2?3.3 %. Further, to analyze the effectiveness of the LT-CF process in preventing thermal stress in comparison to a conventional soldering ribbon (SR) process, the bows of LT-CF-bonded and conventional SR-bonded cells were compared. The average bow of the LT-CF-bonded cells (1.42 mm) was lower than that of the SR-bonded cells (3.15 mm), representing a bow suppression of 54.9 %