Making method of seed crystal for polycrystalline ingot

Abstract

The invention discloses a making method of a seed crystal for a polycrystalline ingot. The making method comprises the steps that a made silicon block is provided; a seed crystal unmelted layer located at the tail portion of the silicon block is cut off; the seed crystal unmelted layer is roasted, and remained colloid located at the bottom of the seed crystal unmelted layer is removed; pickling and soaking are conducted on the seed crystal unmelted layer for first preset time; the seed crystal unmelted layer is crushed into seed crystal particles; the seed crystal particles are soaked with a strong acid mixed liquor for second preset time; the seed crystal particles are subjected to washing, ultrasonic cleaning and drying, and the seed crystal for the polycrystalline ingot is obtained. According to the making method of the seed crystal for the polycrystalline ingot, the bottom unmelted layer can be recycled, the efficient seed crystal which is stable in performance is obtained, the crystal quality of the polycrystalline ingot is improved, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic equipment manufacturing, and in particular relates to a method for making a seed crystal for polycrystalline ingot. Background technique [0002] At present, crystalline silicon solar cells occupy a dominant position in the photovoltaic industry. The cost of silicon wafers accounts for more than half of the cost of single / polycrystalline silicon, so reducing the cost of silicon wafers and improving the quality of silicon wafers are of great significance to the development of the photovoltaic industry. [0003] When using an ingot furnace to grow cast polycrystalline crystals using a semi-melting process, it is necessary to place fine particles at the bottom of the quartz crucible as a seed crystal to form a nucleation seed. Seed crystals, as the foundation of semi-molten high-efficiency nucleation, are the most important part in the ingot casting process. Without high-quality seed crystals, ...

AI Technical Summary

Problems solved by technology

Seed crystals, as the foundation of semi-molten high-efficiency nucleation, are the most important part in the ingot casting process. Without high-quality seed crystals, high-efficiency semi-molten silicon ingots cannot be formed. However, since the existing seed crystals are all primary silicon Seed crystals of granular materials, such as: REC4021, MEMC, Wacker and other granular materials, have high market purchase prices, high cost of seed crystals, and are not reused. The unmelted layer of the cut seed crystals is used as a furnace. relatively high cost

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