Search

26th European Photovoltaic Solar Energy Conference and Exhibition; 2059-2062, An important issue in using thinner multi crystalline silicon wafers for solar cell manufacture is the reduced yield due to higher wafer breakage rates. Wafer/cell breakage depends on the stresses produced in the handling and transport and on the presence of structural defects such as cracks. The types of loading results in different mechanical strength for the sample amplitude (e.g. usually static loading is less critical than vibration). One of the important loading types which have not been focused in the literature is vibration of wafers during handling. This paper presents a systematic approach for the analysis of the response of crystalline silicon wafers to rapid local loading similar to gripping by a suction pad. Various load paths have been considered. The paper highlights the key parameters to consider for this type of loading. In particular, it has been found that the rate of loading causing the vibration during handling is very important.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1240-1243, The mechanical behavior of extrinsic silicon materials is studied using a novel constitutive model. Its ability to correctly reproduce late hardening stages and complex loading conditions is augmented by the incorporation of oxygen locking and unlocking phenomena. The response of a silicon multicrystal to a tensile loading is studied with different impurity concentrations and grain orientations. Inclusions are frequent in solar-grade silicon materials and their effect on dislocation generation and on the build-up of residual stresses is assessed.

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1919-1923, The ability to predict the build-up of residual stresses in multicrystalline silicon (mc-Si) materials during their processing is of utmost importance to assess possible fracture risks and guarantee the final product quality. The conventional mechanical models for the behaviour of mc-Si at high temperatures consider the material as homogeneous and deformed in single slip only. This approach neglects the inter- and intragranular hardening mechanisms that are typical of polycrystals. This paper introduces an advanced constitutive model for silicon single crystals and highlights its prominent features. It is then applied to the simulation of a tensile test of a multicrystalline aggregate. The results point towards highly heterogeneous deformation and stress fields in the specimen and confirm the need of such a mechanical model for the study of mc-Si.