Polycrystalline silicon ingot, manufacturing method thereof, solar cell

Abstract

The invention discloses a preparation method for a polycrystalline silicon ingot. The preparation method comprises the following steps of: paving seed crystals on the bottom of a container in a polycrystalline silicon ingot growth furnace to form a seed crystal layer, wherein the seed crystal layer can be formed by paving a whole large single-crystal seed crystal of which the size and the shape are the same as those of the bottom of the container, or splicing a plurality of small single-crystal seed crystals, or paving blocky plate blanks cut from polycrystalline silicon main bodies; loading solid silicon raw materials above the seed crystal layer; heating the container, smelting the silicon raw materials and part of the seed crystal layer to form a liquid layer, and at least keeping part of the seed crystal layer contacted with the bottom of the container in a solid state; and controlling a thermal field in the polycrystalline silicon ingot growth furnace, and crystallizing the liquid layer to form a crystallizing layer to ensure that a solid interface moves toward the direction far away from the bottom of the container so as to finish growing the polycrystalline silicon ingot. The polycrystalline silicon ingot produced by the method is low in impurity content, and the produced solar cell is low in cost and attenuation coefficient and high in photoelectric conversion efficiency.

Description

technical field [0001] The invention relates to the manufacturing technology of monocrystalline silicon and polycrystalline silicon and the field of optoelectronics, in particular to a polycrystalline silicon ingot, a manufacturing method thereof, and a solar battery. Background technique [0002] Solar cells can convert light energy into electrical energy. The photoelectric conversion efficiency and the speed of battery attenuation are important parameters to measure the quality of solar cells. At present, according to different materials, solar cells are mainly divided into two types: monocrystalline silicon solar cells and polycrystalline silicon solar cells. [0003] Among them, the monocrystalline silicon ingot is formed by melting the silicon raw material containing dopant, and then pulling the crystalline silicon out of the melting region to crystallize. Usually, the method of producing single crystal silicon ingot is the melt Czochralski method (Czochralski method, r...

AI Technical Summary

Problems solved by technology

Compared with monocrystalline silicon ingots, there are more defects in polycrystalline silicon ingots, the grains are small, and there are more grain boundaries and dislocations between conventional polycrystalline silicon grains, resulting in rapid recombination of charge carriers, resulting in low minority carrier lifetime. , and, because the orientation between crystal grains is random, it is difficult to texture the surface of the wafer well, so that the photoelectric conversion efficiency of conventional polycrystalline silicon solar cells is lower than that of monocrystalline silicon solar cells, but the oxygen content in polycrystalline silicon ingots It can be controlled at a good level, so that the attenuation coefficient of polycrystalline silicon solar cells is low

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