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Casting method for polycrystalline silicon ingot

A polycrystalline silicon ingot and polycrystalline furnace technology, which is applied in the field of polycrystalline silicon solar cells, can solve the problems of easy generation of dislocations, disordered crystal orientation, and excessive oxygen content.

Active Publication Date: 2015-04-29
YANGZHOU RONGDE NEW ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the casting method of polycrystalline silicon ingots in the prior art tends to lead to uneven crystal grains, disordered crystal orientations, and dislocations easily, so that the photoelectric conversion efficiency of solar cells made by using the polycrystalline silicon ingots low, and the cost of high-efficiency crucibles in the market is high, and it is easy to cause the problem of excessive oxygen content. A casting method for polycrystalline silicon ingots is provided.

Method used

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  • Casting method for polycrystalline silicon ingot
  • Casting method for polycrystalline silicon ingot
  • Casting method for polycrystalline silicon ingot

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] Embodiment 1: the preparation of polycrystalline silicon ingot

[0065] First, the silicon material is filled into a common crucible sprayed with a silicon nitride coating. That is, spread the blocky head and tail recycled materials on the bottom of the crucible from one corner, and do not leave gaps between the blocky recycled materials. Then spread around the crucible with edge scrap to protect the coating. Then stack the reclaimed crystal bricks in the remaining silicon material, unfinished head and tail reclaimed materials, or large bars in turn around the crucible, and fill the small pieces of reclaimed materials in the middle of the crucible. Go up in turn until the end of loading.

[0066] Heat the crucible containing the silicon material to 1530°C;

[0067] Then, the program enters the melting stage, and the temperature is raised to 1550°C. When the silicon material floats from the bottom of the crucible, open the heat insulation cage to 1 / 2 of the maximum op...

Embodiment 2

[0070] Embodiment 2: the preparation of polycrystalline silicon ingot

[0071] First, the silicon material is loaded into an ordinary crucible sprayed with a silicon nitride coating, the charging method is the same as in Example 1, and the crucible containing the silicon material is heated to 1500 ° C;

[0072] Then, the program enters the melting stage and heats up to 1560°C. When the silicon material floats from the bottom of the crucible, open the heat insulation cage to 1 / 3 of the maximum opening of the heat insulation cage and lower the temperature setting by 10°C to maintain the heat insulation Cage opening and lowered temperature for 30 minutes, raise the temperature to 1560°C, reduce the opening of the insulation cage to 1 / 5 of the maximum opening of the insulation cage, continue to melt at 1560°C for 6 hours, and increase the opening of the insulation cage again to the top 1.8 times the opening degree and set the temperature at 1520°C, keep the opening of the heat ins...

Embodiment 3

[0080] Embodiment 3: the preparation of polycrystalline silicon ingot

[0081] Such as Figure 4 shown, proceed as follows:

[0082] Firstly, polycrystalline fragments with a length of 3-12mm are screened, rinsed with pickling until there is no acid residue, and dried to obtain the bottom layer a; the sorting thickness is 3-5cm, and the size is 156mm×156mm (length×width) silicon material, to obtain the bottom material b;

[0083] Then, evenly sprinkle a layer of the above-mentioned primer a on the bottom of the ordinary crucible until the bottom coating of the high-efficiency crucible cannot be seen visually, then spread the above-mentioned primer b on the bottom of the primer a, and there is no gap between the silicon materials of the primer b. leave a gap;

[0084] Finally, spread the recycled edge skin material around the crucible, then stack the recycled crystal brick material inside the recycled edge skin material, fill the block material in the space formed by the recyc...

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Abstract

The invention discloses a casting method for a polycrystalline silicon ingot. The casting method comprises the steps of charging, namely filling a crucible with a silicon nitride coating with a silicon material; heating, namely heating the crucible by using a polycrystalline furnace, wherein the crucible is obtained in the former step; melting and nucleating, namely melting the silicon material in the crucible through heating, and immediately opening a cage to cool when the silicon material floats from the bottom of the crucible to form a crystal nucleus; and growing a crystal, namely growing a silicon crystal. The polycrystalline silicon ingot produced by using the method disclosed by the invention has the characteristics of short production period, low cost, high silicon ingot quality and the like, and the obtained polycrystalline silicon wafer has the characteristics of uniform grain size, small defect density, high photoelectric conversion efficiency and the like.

Description

technical field [0001] The invention relates to the technical field of polycrystalline silicon solar cells, in particular to a method for casting polycrystalline silicon ingots. Background technique [0002] In recent years, with the depletion of non-renewable energy sources, solar cells have been developed rapidly. With the rapid development of the solar cell industry, polysilicon, which is low in cost and suitable for large-scale production, has gradually replaced Czochralski monocrystalline silicon in the solar cell material market and has become one of the most important photovoltaic materials in the industry. However, various defects in cast polysilicon, such as grain boundaries, dislocations, micro-defects, and impurity carbon and oxygen in the material, make the conversion efficiency of polysilicon cells lower than that of Czochralski monocrystalline silicon solar cells, thus becoming a limiting polysilicon solar cell development bottleneck. Therefore, improving the...

Claims

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Application Information

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IPC IPC(8): C30B28/06C30B29/06
Inventor 常传波杨振帮袁聪冯琰
Owner YANGZHOU RONGDE NEW ENERGY TECH
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