Preparation method of N-type double-sided battery

Abstract

The invention relates to a preparation method of an N-type double-sided battery. The method comprises the following steps of (1) texturing; (2) boron and phosphorus co-diffusion at front and back sides of a textured silicon wafer by adopting a spin-coating method; (3) HF cleaning; (4) PECVD of AlOx and a passivation film at the front side; (5) the passivation film is deposited at the back side bymeans of PECVD; (6) screen printing and sintering; (7) laser edge isolation; and (8) light-heat treatment of the battery. According to the preparation method, the problem of boron and phosphorus diffusion at present is solved, the technological process is effectively simplified, cross contamination of boron and phosphorus elements is avoided and the conversion efficiency of the battery is improved.

Description

technical field [0001] The invention belongs to the field of solar cells, and in particular relates to a method for preparing an N-type double-sided cell. Background technique [0002] With the increasing scarcity of traditional energy and the dual pressure of serious environmental damage, finding clean and renewable energy has become a long-term strategic goal to solve energy problems. Among various new clean energy sources, solar energy is considered as one of the most promising clean energy sources. Solar cells will occupy an important strategic potential in the energy structure and become a major form of energy. Among them, crystalline silicon solar cells are the fastest-growing solar cells and are widely used in large-scale power stations. The main performance is the industrial production of P-type crystalline silicon cells. However, as the related problems of N-type crystalline silicon cells are gradually overcome, P-type The room for improving the efficiency of cryst...

AI Technical Summary

Problems solved by technology

[0004] The method of boron and phosphorus diffusion in the above step ② is divided into the following types: (1) boron diffusion, backside cleaning, etching, and phosphorus diffusion; but this method has a long battery production process, which is not conducive to process control, and the backside cleaning is easy to introduce impurities. Recombination centers are formed by secondary high-temperature phosphorus diffusion, which reduces the minority carrier lifetime of silicon wafers

(2) Coating and drying of boron slurry, advancing at high temperature in the furnace tube, and diffusion of POCl3 in the tube out of the furnace; this process only needs to enter the furnace tube once to complete the co-expansion of boron and phosphorus, eliminating the need for process (1) Middle back cleaning , etching steps, but this method still needs to go through two high temperatures to affect the minority carrier life of the silicon wafer, and the use of POCl3 gas diffusion will easily cause the boron diffusion surface to be doped with phosphorus elements, which will affect the quality of the PN junction and reduce the electrical performance.

[0005] In addition, boron / phosphorus-containing silicon dioxide layers are formed by PECVD deposition on both sides, and then co-diffused on both sides. The uniformity of boron and phosphorus diffusion resistance obtained by this method is poor, and the boron / phosphorus-containing silicon dioxide layer The equipment is not compatible with traditional PECVD equipment and requires additional investment. In order to meet the doping of boron / phosphorus sources in the silicon dioxide layer, the equipment requires special material furnace tubes and boats, so the equipment is expensive and maintains high costs

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