Experimental study on slicing photovoltaic polycrystalline silicon with diamond wire saw

摘要

At present, polycrystalline silicon photovoltaic cells play a dominant role in silicon-based solar cells because of its advantages such as relatively simple preparation process and relatively low cost. Slicing is the first mechanical processing procedure for battery cells, the quality of sawn surface affects the cost of subsequent processes such as texture making, also affects the breaking strength of battery cells and the photoelectric conversion efficiency and other performances. In this paper, polycrystalline silicon sawing experiments are carried out, and the effects of main process parameters, such as the workpiece feed speed, the wire moving speed, the ratio of the workpiece feed speed to the wire moving speed, and the sawn workpiece size, on the surface morphology and roughness R-a of the photovoltaic polycrystalline silicon slice are analyzed. Orthogonal experimental method was used to analyze the primary and secondary order and positive and negative effects of various factors on surface morphology and surface roughness, the optimum process parameters were obtained, and the wear morphology and mechanism of wire were analyzed. The research results show that: within the range of process parameters studied in this paper, the surface morphology of polycrystalline silicon slices shows a comprehensive effect of material ductility and brittleness removal. Reducing the workpiece feed speed and size, increasing the wire moving speed will increase the proportion of the ductile smooth area on the slice surface and decrease the surface roughness R-a value, the slice surface roughness R-a value is basically unchanged when workpiece feed speed and wire speed change at the same time but the ratio of them remains constant. Compared with the wire moving speed and the workpiece size, the workpiece feed speed has the greatest influence on the surface morphology and roughness. Abrasive falling off and coating wear are the main wear forms of the wire.