Polycrystalline ingot furnace and directional solidification device and polycrystalline ingot method thereof

Abstract

The invention discloses a directional solidification device comprising a first insulation board, a second insulation board and a rotating component, wherein the first insulation board and the second insulation board are completely the same in shape and are provided with a plurality of concentric circular ring areas on the surfaces, a plurality of through hole areas with the same size are formed on each concentric circular ring area at equal intervals, and a solid area between two adjacent through hole areas on each concentric circular ring area and the through hole areas are completely the same in shape; the first insulation board is fixed at the lower part of a graphite supporting platform; the second insulation board is fixedly connected with the rotating component, the upper surface of the second insulation board is close to the lower surface of the first insulation board, and the through hole areas on the second insulation board are completely overlapped with, partially overlapped with or separated from the through hole areas on the first insulation board selectively. The invention further discloses a polycrystalline ingot furnace and a polycrystalline ingot method, which can be used for guaranteeing a continuous and stable temperature gradient and ensuring the growth quality of columnar crystals.

Description

technical field [0001] The invention relates to the technical field of photovoltaic equipment manufacturing, in particular to a polycrystalline ingot casting furnace, a directional solidification device, and a polycrystalline ingot casting method. Background technique [0002] Polycrystalline silicon ingot has become the mainstream material for crystalline silicon solar cells due to its low production cost and large output. However, there are defects such as grain boundary disorder, dislocation, inclusions and oxides in the polysilicon ingot. These defects become the recombination center of minority carriers, which reduces the life of photogenerated carriers and makes the efficiency of polysilicon solar cells lower than that of monocrystalline silicon solar cells. Crystalline silicon battery. In order to improve the efficiency of polycrystalline silicon solar cells, large grains or quasi-single crystal ingots can be grown directionally in an ingot furnace. Directional soli...

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Problems solved by technology

[0003] However, the above three methods all have shortcomings. Among them, the temperature field control of the power drop method is discontinuous, and the thermal field is a stepwise mutation from top to bottom, which is not conducive to the growth of columnar crystals; the solidified melt moving down method will generate vibration, It has an adverse effect on crystal growth; when using the lifting insulation cage method, the heat dissipation at the bottom of the crystal is uneven, and the heat dissipation at the four sides is faster than that at the center, which leads to the formation of new crystal nuclei at the edge and the growth of non-columnar crystals, which inhibits the growth of columnar crystals

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