Method for realizing edge insulation of solar cell by wet process

Abstract

The invention discloses a method for realizing edge insulation of a solar cell by wet process. The method comprises the following steps that: firstly, adding a hydrofluoric acid solution into a hydrofluoric acid tank so that part of an idler wheel is immersed into the hydrofluoric acid solution and a moderate amount of hydrofluoric acid solution is contained in tiny grooves of the idler wheel during rotation of the idler wheel; and arranging a silicon wafer on the idler wheel, removing phosphorosilicate glass on the back and edge of the silicon wafer through hydrofluoric acid, and remaining phosphorosilicate glass on the front surface of the silicon wafer; secondly, after the phosphorosilicate glass on the back and edge of the silicon wafer is removed, drying a bit of hydrofluoric acid solution seeping on the front surface of the silicon wafer by windward cutter; and thirdly, feeding the silicon wafer into an etching tank, and corroding PN (positive-negative) junctions on the back and edge of the silicon wafer by the mixed solution of hydrofluoric acid and nitric acid. The method is simple to operate and has good effects.

Description

technical field [0001] The invention relates to the field of solar cell manufacturing, in particular to a method for realizing solar cell wet edge insulation. Background technique [0002] At present, in the solar wet process equipment, when the solar cell is insulated at the wet edge, because the phosphosilicate glass on the surface of the silicon wafer after diffusion has a characteristic, that is, it is very hydrophilic, this characteristic will lead to There is too much liquid medicine turned over to the upper edge, causing over-cutting and reducing the light-receiving area. At present, there are three methods to solve the problem. The first method is to increase the tension of the solution by adding sulfuric acid in the etching tank to prevent the solution from spreading to the upper surface and causing over-etching. However, this method has high requirements on the mechanical precision of the equipment, and also has relatively high requirements on the stability of the...

AI Technical Summary

Problems solved by technology

However, this method has high requirements on the mechanical precision of the equipment, and also has relatively high requirements on the stability of the exhaust air during use, and it is prone to "black edge" chips caused by over-engraving.

The second method is to use the method of spraying up and down to remove the phosphorosilicate glass on both sides first, and then enter the etching tank to remove the edge PN junction. Although this method avoids the liquid turnover problem caused by the hydrophilicity of the phosphorosilicate glass , but the front surface is not protected by phospho-silicate glass, the gas phase corrosion of the etching tank and the corrosion of the alkali tank will cause a rise in square resistance of 3-5 ohms, and may reach 10 ohms in severe cases, which will cause uniform square resistance Poor performance, resulting in increased dispersion of battery efficiency

This method of using water film protection cannot ensure that water will not seep to the edge or even the back, causing the silicon wafer in the etching tank to no longer absorb the chemical solution to etch the PN junction at the edge, resulting in a situation where the etching cannot be done.