Method for separating P-N junction in monocrystal silicon battery piece and method for manufacturing solar battery

Abstract

The invention discloses a method for separating a P-N junction in a monocrystal silicon battery piece and a method for manufacturing a solar battery. The method that the monocrystal silicon battery piece is placed above acid liquor, then the acid liquor is absorbed onto the back surface of the monocrystal silicon battery piece to conduct corrosion so as to remove an N+ layer on the back surface of the monocrystal silicon battery piece is adopted to separate the P-N junction in the monocrystal silicon battery piece. By the adoption of the method, electromotive force which affects pressure opening of the battery can be prevented from being produced on the back surface under the condition of illumination. Moreover, contact between the back surface processed through the method and an aluminum back field becomes evener and flatter, passivation effect is good, response to long waves is benefited, and battery efficiency can be improved. In addition, by the adoption of the scheme, the problem that a silicon wafer is broken cannot be caused. Furthermore, due to the fact that the adopted acid liquor has the effect of removing phosphorosilicate glass already, the step of removing the phosphorosilicate glass does not need to be conducted additionally. Therefore, working procedures are simplified, and further improvement of production efficiency is benefited.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for separating a P-N junction in a monocrystalline silicon cell and a method for manufacturing a solar cell. Background technique [0002] For solar cells, parallel resistance is a very important parameter, and parallel resistance is divided into two types: internal parallel resistance and edge parallel resistance. For a silicon chip, generally 20% of the leakage current passes through the internal parallel resistors, while 80% of the leakage current passes through the edge parallel resistors. In the current solar cell manufacturing method, the P-N junction is made by back-to-back high-temperature phosphorus oxychloride diffusion. This back-to-back diffusion method inevitably diffuses a layer of emitter on the edge of the cell, so that the back field of the fired aluminum After that, there will be a large current leakage at the edge, which will affect the quality of...

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Problems solved by technology

[0004] During the research and practice of the prior art, the inventors of the present invention found that the process of the existing method for separating the P-N junction is relatively cumbersome, and plasma etching only removes the N+ layer at the edge of the battery, while the back of the battery still exists N+ (that is, N positive) layer; when the N+ layer exists, under the condition of light, a back electromotive force will be generated, which will affect the opening voltage of the battery, thereby affecting the performance of the battery. Moreover, the method of plasma etching is easy to damage the silicon wafer, resulting in Fragmentation

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