Texturing method of polysilicon solar cell

Abstract

The invention relates to a texturing method of a polysilicon solar cell. Twice texturing is included, and a combined acid corrosion solution is by formed mixing HNO3, HF and H2O. The texturing method comprises the following steps that A) first texturing is carried out on the polysilicon solar cell by using the mixed acid corrosion solution, in which the mass concentration of HNO3 is greater than that of HF, of the rich HNO3 system; B) the polysilicon solar cell after texturing in step A is cleaned by deionized water; and C) secondary texturing is carried out on the polysilicon solar cell by using the mixed acid corrosion solution, in which the mass concentration of HNO3 is greater than that of HF, of the rich HNO3 system. The solutions used in twice texturing need neither a texturing additive nor other chemicals, the texturing reflectivity of twice texturing is 9% or more lower than that of once texturing traditionally, the light tripping effect of the textured surface is improved, the short circuit current is improved by 200mA or more, and the efficiency is improved by 0.35%; and the texturing method can be combined with a present production line conveniently to reduce the cost and provide convenience for large-scale production.

Description

technical field [0001] The invention belongs to the technical field of crystalline silicon solar cells, and in particular relates to a method for making texture of polycrystalline silicon solar cells. Background technique [0002] In the production process of crystalline silicon solar cells, the conventional production process of polycrystalline silicon solar cells is six processes of texturing, diffusion, etching, PECVD, screen printing, sintering and testing. The traditional acid corrosion texturing method of polycrystalline silicon cells uses The mixed acid of nitric acid and hydrofluoric acid is used as an etching solution for one-step texturing, and the surface of the silicon wafer is oxidized by the oxidation of nitric acid to form silicon dioxide; then the formed silicon dioxide is dissolved by hydrofluoric acid to form a microscopic appearance It is a worm-like corroded suede surface. The suede surface prepared by one-step texturing has a high reflectance of more tha...

AI Technical Summary

Problems solved by technology

[0002] In the production process of crystalline silicon solar cells, the conventional production process of polycrystalline silicon solar cells is six processes of texturing, diffusion, etching, PECVD, screen printing, sintering and testing. The traditional acid corrosion texturing method of polycrystalline silicon cells uses The mixed acid of nitric acid and hydrofluoric acid is used as an etching solution for one-step texturing, and the surface of the silicon wafer is oxidized by the oxidation of nitric acid to form silicon dioxide; then the formed silicon dioxide is dissolved by hydrofluoric acid to form a microscopic appearance It is a worm-like corroded suede surface. The suede surface prepared by one-step texturing has a high reflectance of more than 24%, but the light trapping effect is poor, and the preparation process is prone to flower, sequins or dark lines, which affects the quality of the cell. Appearance and Photoelectric Conversion Efficiency

The metal-catalyzed chemical etching method developed by the researchers is to deposit precious metal particles on the surface of polycrystalline silicon cells to catalyze the corrosion of black silicon technology to prepare micro-nano-scale composite textured surfaces. Although the light trapping effect is good, the precious metal impurities introduced during the preparation process are relatively small Difficult to remove, these precious metal particles form serious recombination centers on the surface of polysilicon cells. In addition, when depositing SiNx passivation anti-reflection film in PECVD process, it is difficult to passivate the nano-scale corrosion pits well, and a large number of exposed pits are formed on the surface. The recombination center of black silicon can not reflect the light-trapping advantages of black silicon

Moreover, the cost of precious metals is high, which greatly increases the cost of black silicon preparation, and there are certain limitations in large-scale production.

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