MR IVAN SAHA, President & CTO – VIKRAM SOLAR | Topic: Study On Module Performance Correlation To Cell/Wafer Characteristics
High volume module manufacturing involves processing of multiple types of cell and wafers from different suppliers / manufacturing lines. Performance of a module and it’s long term reliability is strongly linked with the input cell and the manufacturing process of stringing and lamination processes carried out subsequently.
In this paper we will attempt to characterize module manufacturing metrics like CTM % (Cell to Module conversion loss), Peel Strength between the soldered ribbon and the cell metallization, Light induced Degradation (LID), Fill Factor % and other electrical data to the quality parameters of cell used. Solar Cell electrical parameters like Open circuit voltage (Vᴏc), Short circuit current (Isc) and the Recombination densities (J₀₁ % J₀₂) extracted from dark I-V (Current – Voltage) characteristics, can be used to correlate module performance based on large volume manufacturing data.
A limited numbers of modules were subjected to environmental tests like Light Induced Degradation (LID), Potential Induced Degradation (PID) and HAST Tests like Thermal Cycling Tests and Damp Heat Test.
The impact of slurry-cut wafers and DW cut wafers on the cell and subsequent module performance is also presented. It is interesting to note that there is a strong correlation of the method of cutting silicon block into wafers and subsequent cell fabrication process with CTM % and module life as extrapolated from long duration reliability tests.