Preparation method of N-type crystalline silicon back emitter junction solar battery and corrosive liquid

Abstract

The invention discloses a preparation method of an N-type crystalline silicon back emitter junction solar battery and corrosive liquid. The preparation method comprises the following steps of adopting the corrosive liquid to conduct chemical thinning on an N-type crystalline silicon sheet and enabling the thickness to be reduced to 50-150 mum, and then using a standard process to prepare the solar battery. The corrosive liquid used in the preparation method of the N-type crystalline silicon back emitter junction solar battery is further disclosed. The corrosive liquid is composed of nitric acid, hydrofluoric acid, water and / or acetic acid. The N-type crystalline silicon back emitter junction solar battery prepared by using the method is high in battery efficiency, when the substrate material is the polycrystalline silicon sheet or low-weight monocrystalline silicon sheet, the battery efficiency is obviously promoted, related process equipment is all existing equipment on a P-type solar battery production line, no big cost needs extra investing, operation is simple, and the preparation method and the corrosive liquid are favorable for large-scale application in the photovoltaic industry.

Description

technical field [0001] The invention relates to the field of solar cell materials, in particular to a method for preparing an N-type crystalline silicon back-emitting junction solar cell and a used etching solution. Background technique [0002] Solar energy is an inexhaustible and inexhaustible clean energy. Using the photoelectric conversion characteristics of semiconductor materials, it can be prepared into solar cells, which can convert solar energy into electrical energy. In the last ten years, the production of solar cells has grown at an annual rate of 30-40%, and the solar industry has become one of the fastest growing industries in the market today. [0003] The current solar cell technology is mainly based on P-type crystalline silicon as the substrate material. If N-type crystalline silicon is used to prepare traditional front-emitter junction solar cells, boron diffusion is required, which involves boron diffusion furnaces and a series of The relevant equipment ...

AI Technical Summary

Problems solved by technology

[0003] The current solar cell technology is mainly based on P-type crystalline silicon as the substrate material. If N-type crystalline silicon is used to prepare traditional front-emitter junction solar cells, boron diffusion is required, which involves boron diffusion furnaces and a series of The relevant equipment is almost equal to a new production line; if N-type solar cells are made on the original P-type solar cell production line, the back-emitting junction can be formed by aluminum alloying on the back, and the back-emitting junction solar cell is obtained. Publication No. The patent application for CN 101150148B discloses that the sintering of the aluminum-silicon alloy and the sintering of the back electrode are carried out separately through two times of screen printing aluminum paste and two times of sintering, which solves the problem of electrode weldability and weldability due to the full cover of aluminum on the back. The problem of poor solderability makes it possible to achieve large-scale production of aluminum back-emitting junction N-type monocrystalline silicon solar cells. However, for back-emitting junction solar cells, the diffusion length of the substrate material needs to be at least three times the thickness of the crystalline silicon wafer , only in this way can the photo-generated carriers excited near the front surface be effectively collected by the emitter junction on the back of the cell, and the current standard thickness of crystalline silicon wafer cutting is 180-200 μm. For N-type polycrystalline silicon wafers and low-quality N type monocrystalline silicon wafer, its minority carrier diffusion length is often difficult to reach 500-600 μm, and the short-circuit current of the prepared back-emitting junction solar cell is low, resulting in low final cell efficiency

[0004] Based on the advantages of low light attenuation characteristics and strong tolerance to transition metals of N-type crystalline silicon materials, people have attracted more and more attention in recent years, but due to the existence of the above reasons, N-type crystalline silicon materials are widely used in the field of solar cells. The use of