Description du projet :
In order to compete with traditional fossil energy, the photovoltaic industry is driven to make solar panels of the highest power conversion efficiency, with high reliability at the lowest possible production costs. The crystalline silicon wafers used for the solar cells are sliced down to thicknesses of 80 ' 200 'm. The sawing process leads to the generation of micro-cracks in the wafers. As the module ages and is subjected to thermal and mechanical loads, these micro-cracks can result in the loss of the wafer integrity and ultimate breakage of silicon wafers and cells, resulting in inactive cell parts and significant power loss.
The main objective of this project is the optimisation and thus, the improvement of the photovoltaic module efficiency by evaluating the potential of an ultrasonic based method for the detection and quantification of the micro-cracks produced during the sawing process. The characterization of the wafers in terms of crack size and crack density will enable i) to optimize the slicing process in order to reduce micro-crack generation into a non-critical level, and ii) to identify and reject silicon wafers with a high risk of failure. The proposed methodology is based on the scattering of acoustic guided waves by discontinuities such as micro-cracks for quality evaluation of wafers with a view to efficiency improvement of crystalline silicon-based solar cells. The investigation of wave propagation and defect detectability will be complemented by numerical simulations.
Forschungsteam innerhalb von HES-SO:
, Robyr Jean-Luc
, Banakh Oksana
, Masserey Bernard
Partenaires académiques: Dispositifs médicaux
Durée du projet:
01.03.2012 - 30.09.2013
Montant global du projet: 121'000 CHF