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Silicon wafer thickness reduction without increasing the wafer strength leads to a high breakage rate during subsequent handling and processing steps. Cracking of solar cells has become one of the major sources of solar module failure and rejection. Hence, it is important to evaluate the mechanical strength of solar cells and influencing factors. The purpose of this work is to understand the fracture behavior of silicon solar cells and to provide information regarding the bending strength of the cells. Triple junctions, grain size and grain boundaries are considered, to investigate the effect of crystallinity features on silicon wafer strength. Significant changes in fracture strength are found as a result of metallization morphology and crystallinity of silicon solar cells. It is observed that the aluminum paste type influences the strength of the solar cells.

During each processing step of multicrystalline (mc) silicon solar cells production, it requires a good mechanical stability to avoid cell breakage. Therefore, wafers and cells with a good mechanical stability are absolutely important. The cracking of silicon wafer solar cells is one of the major failures of solar module. Hence, it is important to evaluate the mechanical strength of solar cells and influenced factor. The present work focuses on determining the effect of metallization conditions on mechanical strength of multi crystalline silicon solar cells. A 4-point bending method was used to measure the fracture strength and data is statistically evaluated by a Weibull analysis for interpretation of the flaws within the specimen. It was observed that drying temperature at 250 °C provides better results than 350 °C. It was found that the contact formation between metal layer and silicon wafer (i.e. eutectic layer) has a significant effect on mechanical properties of mc-silicon solar cells. Moreover, the mesh sizes of screen printing produce different thickness of metal layer without altering the strength of silicon wafer. It was discovered that the metallization process was responsible to alter the mechanical strength of mc-silicon solar cell. It is also observed that the crack can initiate from the edge and surface defects and propagate along the preferred crystallographic plane. It was found that the edge defects look like more dominant as crack initiation.

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