Optimization of heat and mass transfer properties of directional solidification process for improving the solar cell performance

Abstract

The heat and mass transport in the Directional Solidification (DS) process can be optimized by numerical simulation. The efficiency of solar cells is mainly affected by von Mises stress, impurities and dislocations, which are introduced during the growth process. Thermal stress is a major factor which is responsible for the generation of dislocations. Therefore the control of the thermal distribution is needed to improve the quality of ingot, but it is a complex issue. In this thesis, optimizing the process parameters, modification of furnace component designs, and their effects have been analyzed using 2D axial-symmetry model. Uniform thermal field is very important for producing high-quality mc- Silicon ingots. The growth rate is dependent on the temperature gradient. A transient global model of heat transfer was developed to investigate the thermal gradient, interface shape, impurities distribution and thermal stress by introducing different modifications in the DS system. In this thesis, the effect of different modification on the defects like thermal stress, impurities and dislocation density in the ingot using CGSim software. First chapter explains the introduction of the photovoltaic of the renewable energy sources and discusses the general background of solar cell generations. The different method involved of silicon growth process has been discussed. This chapter discusses the brief literature survey on directional solidification process. And also discusses wafer to cell making process. Second chapter optimizes the growth process of the DS furnace for improving the mc-Silicon ingot quality by using numerical simulation newline