MWT cell with back passive film and preparation method thereof

Abstract

The invention discloses a preparation method of an MWT cell with a back passive film. The preparation method comprises the steps that wet texturing is performed on a provided silicon wafer; phosphorus diffusion or boron diffusion is performed on the silicon wafer; the edge and the back surface emitter of the silicon wafer are etched, and a PSG or a BSG is removed; the silicon wafer is punched; the silicon wafer is cleaned by hydrofluoric acid; the back passive film is deposited on the back surface of the silicon wafer; a protection film is deposited on the back surface of the silicon wafer; an anti-reflection passive film is deposited on the front surface of the silicon wafer; a slot is arranged in the non-emitter electrode printing region of the back surface of the silicon wafer; an emitter electrode and a base contact electrode are printed on the back surface of the silicon wafer, and through holes distributed at the center position of the emitter electrode are filled; and an aluminum back field is printed on the back surface of the silicon wafer, and fine gate lines are printed on the front surface. Correspondingly, the invention also provides the MWT cell prepared by the preparation method. With application of the preparation method, electric leakage around the through holes can be reduced so that photoelectric conversion efficiency of the MWT cell can be substantially enhanced.

Description

technical field [0001] The invention belongs to the field of solar cell preparation, and in particular relates to a MWT cell with a back passivation film and a preparation method thereof. Background technique [0002] MWT cell is the abbreviation of metallization wrap-through (MWT) silicon solar cell. The MWT battery transfers the front electrode to the back of the battery, and only retains the thin grid lines on the front of the battery, thereby reducing the shading area on the front of the battery and improving the photoelectric conversion efficiency of the solar cell. [0003] At present, the technical difficulty of MWT batteries is to solve the leakage problem near the hole. Adding a back passivation film in the preparation of MWT batteries, combined with the improvement of the printing screen can reduce the leakage of MWT batteries to below 0.5A. The back passivation film can greatly increase the back reflectivity of the solar cell and greatly reduce the back recombina...

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problems of large leakage and low efficiency of MWT batteries existing in the prior art, the invention provides a method for preparing MWT batteries with a back passivation film

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