High-efficiency PERC solar cell and preparation method thereof

Abstract

The invention discloses a preparation method for a high-efficiency PERC solar cell, and the method comprises the steps of sequentially carrying out the texturing, diffusion and etching processing on asilicon wafer, forming an anti-reflection film and a passive film, and carrying out the silk-screen printing on the electrode slurry to obtain a solar cell green body; and then sequentially carryingout the drying, sintering, annealing, illumination and cooling processing on the solar cell green body to obtain a PERC solar cell finished product. Correspondingly, the invention also discloses the high-efficiency PERC solar cell. According to the invention, through the processes of primary high-temperature annealing after firing, illumination-assisted secondary annealing and cooling, the hydrogen, metal impurities and a B-O complex in the solar cell are effectively activated at the earlier stage, and the regeneration of the H and B-O complex from an unstable state to a passivated stable state is effectively promoted at the later stage, so that the CID attenuation rate of the PERC solar cell is effectively reduced, and the conversion efficiency is improved. Through the preparation method,the average attenuation rate of the CID can be reduced to below 1%, and the absolute value of the efficiency of the solar cell is improved by 0.1-0.3%.

Description

technical field [0001] The invention relates to the field of solar cells, in particular to a high-efficiency PERC solar cell and a preparation method thereof. Background technique [0002] At present, the mainstream products in the solar cell industry have been upgraded from traditional Al-BSF (Aluminum Back Field Contact) cells to PERC (Passivated Emitter Rear Cell) solar cells. The point contact greatly reduces the backside recombination loss of the solar cell, increases the open circuit voltage of the solar cell, and significantly improves the efficiency of the solar cell. The current mass-produced PERC solar cell generally has an efficiency of more than 21%. However, people's expectations for the conversion efficiency of solar cells do not stop there, and the current improvement of the conversion efficiency of PERC cells is facing great challenges. [0003] During the use of PERC solar cells, power attenuation is prone to occur, that is, the conversion efficiency of sol...

AI Technical Summary

Problems solved by technology

The CID decay rate of PERC solar cells after conventional sintering treatment can reach 2-5%, which seriously affects the power level of solar cells after packaging

[0004] At present, there is no consensus on the attenuation mechanism caused by carriers. The photovoltaic industry currently speculates on the CID mechanism for the following reasons: 1) Light-induced degradation (LID) : The power attenuation caused by the battery in the light process is generally believed in the industry that LID is mainly caused by boron-oxygen complexes and boron-iron pairs; its attenuation can reach 3-7%, and some can even be as high as 10%; 2) light-thermal attenuation (LeTID ): The power attenuation caused by the battery under high temperature and light conditions can reach about 10%; 3) Hydrogen-induced decay (HID), the hydrogen bonds of passivated impurities and defect parts are easily damaged by high temperature and / or light, Entering the silicon wafer body, it induces the formation of a recombination center, causing attenuation; 4) the metal dissolves and disperses, and the metal precipitate disperses to form interstitial metal ions during the high-temperature rapid burning process. The metal atoms can activate impurities and cause attenuation

In the existing technology, there are many studies on LID and its coping strategies, but less research on CID coping strategies

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