Alkali polishing preparation method of PERC solar cell

Abstract

The invention discloses an alkali polishing preparation method of a PERC solar cell. The method comprises texturing, diffusion, front laser processing, etching, annealing, back passivation film processing, front passivation film processing, back laser processing, silk-screen printing and sintering. The method is characterized in that, before the texturing step, an alkali polishing step and a silicon dioxide film deposition step are further included, wherein in the alkali polishing step, a potassium hydroxide solution is adopted to polish the silicon wafer, in the back surface silicon dioxide film deposition step, a layer of silicon dioxide mask is plated on the back surface of the silicon wafer by adopting a PECVD technology, and in the texturing step, a potassium hydroxide additive is added for texturing. According to the method, the flatness of the back surface of the prepared battery piece is improved, the passivation effect of the back film is improved, the open-circuit voltage isimproved, and the conversion efficiency of the battery is further improved.

Description

technical field

[0001] The invention relates to the technical field of solar cells, in particular to a method for preparing PERC solar cells by alkali polishing. Background technique

[0002] At present, PERC crystalline silicon solar cells are the mainstream products in the market, the production process is becoming more and more mature and perfect, and the cell efficiency is approaching the bottleneck. Such as figure 2 As shown, the preparation process of the existing PERC solar cell technology is as follows:

[0003] 1. Texture making: use wet technology to form a textured surface on the surface of the P-type monocrystalline silicon wafer;

[0004] 2. Diffusion: P-N junction is formed by diffusion;

[0005] 3. Front laser: Prepare selective emitter, and use laser to do heavy doping on the surface of silicon wafer;

[0006] 4. Etching: use HF / HNO3 solution for back polishing, and use HF to remove phosphosilicate glass (PSG) formed during the front and back diffusion ...

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