Manufacturing process of solar cell

Abstract

The invention relates to a manufacturing process of a solar cell. The manufacturing process of the solar cell comprises the cleaning step, the melting step, the diffusion step, the phosphorosilicate glass removal step, the film coating step, the printing step and the sintering step. The manufacturing process is characterized in that according to the diffusion technology, a crystalline silicon substrate reacts with oxygen and phosphorus oxychloride under the conditions that the temperature ranges from 800 DEG C to 900 DEG C, the flow of the oxygen ranges from 900 L / min to 1100 L / min, the large-amount nitrogen flow ranges from 1750 L / min to 1800 L / min, and the small-amount nitrogen flow ranges from 1750 L / min to 1800 L / min, so that PN junction is formed. An alkali cleaning working procedure further exists between the phosphorosilicate glass removal working procedure and the film coating working procedure. The alkali cleaning working procedure comprises the following steps of (1) alkali cleaning, wherein an alkali solution reacts with the surface of a silicon chip; (2) washing, wherein water is used for flushing the alkali solution on the surface of the silicon chip; (3) neutralization, residual alkali on the surface of the silicon chip is neutralized through weak acid; (4) washing, wherein residual weak acid on the surface of the silicon chip is washed away through water; (5) dewatering and drying, wherein dewatering and drying are carried out on the silicon chip processed through the steps.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a manufacturing process of solar cells. Background technique [0002] A solar cell, also known as a photovoltaic cell, is a semiconductor device that uses the photovoltaic effect to convert the light energy of the sun into electrical energy. The so-called photovoltaic effect refers to the phenomenon that the P-type semiconductor and the N-type semiconductor are connected first, and then a potential difference is generated between the P-type semiconductor and the N-type semiconductor through light; Energy photons can excite electrons from covalent bonds in P-type silicon and N-type silicon, so that electron-hole pairs are generated at the interface between P-type silicon and N-type silicon. Before electrons and holes recombine, The electric field effect of the space charge is separated from each other; electrons move to the positively charged N-type silicon region, and holes ...

AI Technical Summary

Problems solved by technology

In the PN junction of the solar cell, the P-type silicon is only provided with a thin layer on the upper surface of the solar cell, because if the P-type silicon, that is, the silicon crystal containing more free electrons, is made large and thick, then During the movement of free electrons to N-type silicon, they will be recombined by holes, which is not conducive to the transformation of the photorecombination effect. Therefore, the proportion of N-type silicon in solar cells is very large, and N-type silicon is where free electrons are relatively large. It is well known that the resistance of an object is determined by the number of free electrons that can move in the object, and because it is desired to make P-type silicon thinner and N-type silicon thicker in the process of producing solar cells. , the macroscopic manifestation is that the square resistance of solar cells will be higher; in the production of solar cells, people hope to produce solar cells with high square resistance and uniform distribution of square resistance in a solar cell, but so far The technical production process can already produce high square resistance solar cells through the processes of melting, diffusion, dephosphorous silicon glass, coating, printing and sintering, but the existing problem is: to realize high square resistance solar cells through the diffusion process The square resistance of the sheet will have uneven distribution of the size of the square resistance. This is because the amount of phosphorus atoms infiltrated into the surface of the crystalline silicon will be controlled in the diffusion process under the premise of ensuring a high square resistance. After removing the phosphosilicate glass layer, the surface of the silicon wafer will Phosphorus atoms are not evenly distributed, resulting in uneven distribution of the square resistance of the solar panel

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