Solar cell grid line laser-induced printing method based on silicon wafer double-groove structure

Abstract

The invention discloses a solar cell grid line laser-induced printing method based on a silicon wafer double-groove structure, and the method comprises the steps: employing a laser to etch the double-groove structure on a silicon wafer so as to limit a grid line printing region, and employing a laser-induced silver paste film to generate a silver paste bridge between a transparent substrate and adouble-groove limiting region, enabling the laser to scan in the extension direction of the groove interval area so that expansion of the silver paste bridge can be realized; and stretching the silverpaste bridge by vertically moving the transparent substrate until the silver paste bridge is broken, and finally obtaining the grid line with high precision and high aspect ratio on the silicon wafer. Compared with a traditional silk-screen printing technology, the cost can be reduced, and the breakage rate can be reduced. Compared with an original laser-induced transfer method, due to the existence of the grooves, the contact area of the silver paste and the silicon wafer is limited in the groove interval area. Therefore, the grid line with more stable width, higher precision and higher depth-to-width ratio can be obtained.

Description

technical field [0001] The present invention relates to a method for laser-induced printing of solar cell grid lines based on a silicon wafer double-groove structure, in particular to the realization of grid line printing of photovoltaic solar cells by using laser induced forward transfer technology (Laser induced forward transfer, referred to as LIFT) The method belongs to the field of laser application and photovoltaic technology. Background technique [0002] A photovoltaic solar cell is a device that uses the photovoltaic effect to convert light energy into electrical energy. Solar cell front electrode polarization is one of the most important steps in the production process of photovoltaic solar cells. Screen printing is often used to print the solar front silver paste on the front of the solar cell. However, there are two major defects in screen printing. First, screen printing is a contact printing method, which can easily cause damage to silicon wafers during the pr...

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Problems solved by technology

[0004] So far, LIFT technology has proved that it can be applied to the front polarization of solar cells, but due to the limitation of the transfer mechanism, only grid lines with a width of more than 40 μm can be obtained, the aspect ratio of the grid lines is about 0.5, and the obtained grid line width There will be slight fluctuations, fluctuations in ±5μm

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