Composite baffle used for polysilicon casting

Abstract

The invention relates to a composite baffle used for polysilicon casting. The composite baffle comprises an insulation body installed inside a graphite baffle, which is coated around the insulation body. With the invention, in a process of directional solidification ingot casting, gradient temperature distribution inside a crucible can be more uniform, a solid-liquid interface can be close to a plane, so that the edge of an ingot can approach the center in terms of properties and the effective utilization rate of the ingot can be substantially enhanced. Also, during crystal growth, the temperature gradient is increased, thus increasing crystal growth speed and lowering production cost. In addition, the design concept of the baffle in the invention can be used in directional solidification technologies of other crystals.

Description

technical field [0001] The invention belongs to the field of solar photovoltaic power generation, and in particular relates to a composite material baffle used for growing and casting multi-body silicon. Background technique [0002] At present, monocrystalline silicon and polycrystalline silicon are the most commonly used materials for solar cells. The polycrystalline silicon material has a photoelectric conversion efficiency close to that of monocrystalline silicon due to the use of directional solidification ingot casting technology, large grain growth or quasi-single crystal growth technology, and its production The cost is much lower than that of monocrystalline silicon, so more polycrystalline silicon ingots are used for crystalline silicon solar cells. [0003] In the production of polysilicon ingots, two problems are usually encountered. First, the polysilicon close to the crucible wall is polluted by the crucible wall, thereby reducing the efficiency. Therefore, a ...

AI Technical Summary

Problems solved by technology

Because the graphite baffle is used on the outside of the quartz crucible, its thermal conductivity is high, causing the isotherm distribution on the edge of the crucible to seriously deviate from the horizontal position - the isotherm is obviously bent upward at the edge of the crucible, so that the shape of the solid-liquid interface is not horizontal, but The surface is concave, and the temperature gradient at the edge is much higher than that at the center of the crucible, which results in the rapid growth of inefficient polysilicon at the edge of the ingot and a large increase in energy consumption

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