Investigation of wettability and interface reactions of Sn-Pb, Sn-Cu, Sn-Ag and Sn-Ag-Cu solders for solar cell interconnections

The soldering and wetting behaviour for lead-contained and lead-free solders joints has been well studied in electronics packaging applications over the past years. Lead-contained solders were widely used because of their well know wetting behaviour and mechanical properties, even in solar cell string soldering. Establishing the Si crystalline solar cell module manufacturing as an environment-friendly process more substantial income of the soldering process reliability and efficiency for photovoltaic applications is still necessary. The paper reveals key parameters to ensure the quality and reliability of solar cell joint interconnections and shows that the conditions of wetting behaviour and microstructural properties are of tremendous importance for silicon-based photovoltaic modules with lifetime guarantees up to 25 years.