Ingot casting process for high-efficiency polycrystalline silicon

A polysilicon, high-efficiency technology, applied in the field of solar cells, can solve problems such as low conversion efficiency, and achieve the effect of low cost and easy operation

Active Publication Date: 2013-01-30
东海晶澳太阳能科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, various defects in cast polycrystalline silicon, such as grain boundaries, dislocations, micro-defects, and impurity carbon and oxygen in the material, make the conversion efficiency of the cell slightly lower than that of Czochralski monocrystalline silicon solar cells

Method used

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  • Ingot casting process for high-efficiency polycrystalline silicon
  • Ingot casting process for high-efficiency polycrystalline silicon
  • Ingot casting process for high-efficiency polycrystalline silicon

Examples

Experimental program
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Effect test

Embodiment 1

[0032] The high-efficiency polysilicon ingot casting method provided by this embodiment includes the following steps:

[0033] (1) Support and fix the carbon felt with a thickness of 150mm and a width of 80mm within 50~200mm below the heaters on both sides of the ordinary ingot casting furnace, and the carbon felt is close to the side wall insulation material;

[0034] (2) Put the silicon raw material and the boron-silicon alloy into the crucible, about 480kg in total, and the target resistivity is 1.5Ω·cm;

[0035] (3) Put the crucible filled with silicon material into the ingot furnace, evacuate and heat, and control the heater to gradually increase the temperature in the furnace to 1540°C. When the silicon material and the electroactive dopant are completely melted, the crucible The bottom temperature is 1400°C;

[0036] (4) After melting, jump into crystal growth. In the initial stage of crystal growth, quickly lower the temperature from 1540°C to 1425°C, and at the same ...

Embodiment 2

[0041] The high-efficiency polysilicon ingot casting method provided by this embodiment includes the following steps:

[0042] (1) Support and fix the carbon felt with a thickness of 200mm and a width of 90mm within the range of 50~250mm below the common ingot furnace heater, and the carbon felt is close to the side wall insulation material;

[0043] (2) Put the silicon raw material and the boron-silicon alloy into the crucible, about 480kg in total, and the target resistivity is 1.7Ω·cm;

[0044] (3) Put the crucible filled with silicon material into the ingot furnace, evacuate and heat, and control the heater to gradually increase the temperature in the furnace to 1540°C. When the silicon material and the electroactive dopant are completely melted, the crucible The bottom temperature is 1405°C;

[0045] (4) After melting, jump into crystal growth. In the initial stage of crystal growth, quickly lower the temperature from 1540°C to 1425°C, and at the same time quickly open t...

Embodiment 3

[0050] The high-efficiency polysilicon ingot casting method provided by this embodiment includes the following steps:

[0051] (1) Support and fix a carbon felt with a thickness of 250mm and a width of 100mm within the range of 50~300mm below the common ingot furnace heater, and the carbon felt is close to the side wall insulation material;

[0052] (2) Put the silicon raw material and the boron-silicon alloy into the crucible, about 480kg in total, and the target resistivity is 1.9Ω·cm;

[0053] (3) Put the crucible filled with silicon material into the ingot furnace, evacuate and heat, and control the heater to gradually increase the temperature in the furnace to 1540°C. When the silicon material and the electroactive dopant are completely melted, the crucible The bottom temperature is 1405°C;

[0054] (4) After melting, jump into crystal growth. In the early stage of crystal growth, quickly lower the temperature from 1540°C to 1430°C, and at the same time quickly open the ...

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Abstract

The invention discloses an ingot casting process for high-efficiency polycrystalline silicon. The process comprises the steps of (1) arranged heat-insulating strips below heaters on two sides of an ingot casting furnace; (2) filling a silicon material and an electroactive doping agent into a quartz crucible, and sending the quartz crucible into the ingot casting furnace; (3) heating to completely melt the silicon raw material and the electroactive doping agent; (4) adjusting the temperature of heaters to be in a range of 1425-1440 DEG C at the initial period of crystal growth, quickly opening a heat-insulating bottom plate, and adjusting the opening the heat-insulating bottom plate to be in a range of 1-8cm, wherein a layer of dendritic crystals are grown longitudinally along the bottom of the crucible; and (5) controlling the temperature gradient of a solid-liquid phase at the middle period and the later period of crystal growth, keeping a straight solid-liquid interface with dendritic crystals at the bottom serving as seed crystals, and producing polycrystalline silicon containing a large amount of twin crystals through directional solidification in a vertical upward direction. Polycrystalline silicon chips are produced by the ingot casting process, the battery efficiency is 0.4-0.6% higher than that of ordinary polycrystalline silicon, the average battery efficiency of integrated ingot silicon chips reaches 17.5%, and the maximum efficiency can be up to 18%.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a high-efficiency polysilicon ingot casting method. Background technique [0002] Ingot casting technology is an important technology in the solar energy industry, and its core technology is also constantly being developed and upgraded. The first-generation ingot casting technology uses silicon liquid in a crucible or without a crucible, and the heat flow flows out from the bottom or side to keep the silicon material gradually solidified, and its growth interface is uncontrollable, eventually forming a silicon ingot. The second-generation ingot casting technology is directional solidification ingot casting technology, which mainly controls the solid-liquid interface temperature to make the silicon liquid interface flat or slightly convex, and the silicon liquid convection is strong, so as to ensure the directional growth of crystals. The high-efficiency polysilic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B28/06C30B29/06
Inventor 黄新明钟根香明亮
Owner 东海晶澳太阳能科技有限公司
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