Manufacturing method of back surface polishing crystalline silicon solar battery

Abstract

The invention discloses a manufacturing method of a back surface polishing crystalline silicon solar battery. The method comprises the following concrete steps: performing texturing and cleaning before diffusion; performing the diffusion; performing wet etching and PSG removal; plating a front surface with a silicon nitride film; plating a back surface with an alundum (Al2O3) membrane; performing laser groove etching; and performing screen printing and sintering. The method is characterized in that before the texturing and the cleaning before the diffusion, a back surface membrane plating process is also arranged, i.e., the back surface of an initial P-type silicon chip is plated with the silicon nitride film with a mask effect according to a conventional method. Compared to a conventional process, the method has the following advantages: only the back surface membrane plating process is added before a texturing and pre-diffusion cleaning process begins, at the same time, an individual back surface polishing process of the P-type silicon chip is omitted, back-surface polishing of the P-type silicon chip can also be realized, damage caused by the individual back surface polishing process to a solar battery N-type diffusion layer is avoided, and therefore, the photoelectric conversion efficiency of the crystalline silicon solar battery can be improved.

Description

Technical field [0001] The invention relates to the manufacturing field of crystalline silicon solar cells, and in particular to a method for manufacturing a back surface polished crystalline silicon solar cell. Background technique [0002] Surface polishing can improve the uniformity of the back surface field, and is particularly beneficial to the realization of the local point contact process on the back surface. The texturing process in the crystalline silicon solar cell manufacturing process will cause the back surface of the cell to form such as figure 1 The suede structure shown, due to the presence of suede on the back surface, makes the wet etching and PSG removal process unable to polish the back surface. In this way, it is necessary to add a separate back surface polishing process after the wet etching and PSG removal process to realize the back surface polishing of the solar cell. Such as image 3 As shown, the normal back surface polishing local point-contact crysta...

AI Technical Summary

Problems solved by technology

[0003] As mentioned above, the acid solution used in the back surface polishing process will volatilize to form acid mist, which will corrode the N-type diffusion layer of the solar cell, thereby destroying the PN junction of the solar cell and reducing the conversion efficiency of the solar cell

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