A method for reducing efficiency loss of solar cells after cutting and solar cells produced by the method

Abstract

The invention discloses a method for reducing efficiency loss of a cut solar cell. The method specifically comprises the following steps: cutting a solar cell through first laser by the general laser cutting mode; arranging second laser close to the side edge of the solar cell to be cut; scribing the side edge of the solar cell to be cut by the second laser while cutting the solar cell through the first laser, wherein the N type layer of the solar cell is scribed, and the whole scribing process is continuous. According to the method, the side edge of the solar cell to be cut is scribed through the laser, thus quantity of minority carriers produced close to a PN joint under the effect of illumination cannot be directly transversely dispersed to reach a defect combining center at the side edge cutting loss part to be combined, thus the service lives of the minority carriers can be prolonged, and as a result, the efficiency loss of the cut solar cell can be reduced; in addition, the scribing is performed while cutting the solar cell, and therefore, the production efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of solar energy utilization, and in particular relates to a method for reducing efficiency loss of a solar cell after cutting and a solar cell produced by the method. Background technique [0002] At present, the use of photovoltaic power generation technology to supply electric energy has been widely used in more and more industries and fields, such as megawatt-level large-scale photovoltaic power plants, small distributed household power supply systems, and mobile traffic signal lights. , Photovoltaic water pumps, calculators and toys, etc. Due to the different fields of application, the form and structure also have different requirements, so there are different requirements for the shape and size of the solar cells used. At present, due to the production process, the most widely used ordinary crystalline silicon solar cells usually have an external dimension of 156cm×156cm or 125cm×125cm. [0003] Since...

AI Technical Summary

Problems solved by technology

Ordinary solar cells, which are semiconductor devices produced by a specific production process, have significantly reduced photoelectric conversion efficiency due to mechanical or thermodynamic effects, which weakens their photovoltaic power generation performance and limits the application of cut solar cells.

The main reason for the obvious decline in the efficiency of the solar cell after cutting is that the bond breaks at the edge after cutting, especially near the PN junction and at the edge of the light-receiving surface, forming many dangling bonds, so that the light generated by the photoelectric effect Carriers are easy to form recombination at the edge; on the other hand, due to cutting, stress or thermal defects are generated at the edge, and the edge is exposed to air and is polluted, which can easily make the edge a serious recombination area of ​​carriers, reducing the Various electrical performance parameters of solar cells

Since different applications have different requirements for the shape and size of cut solar cells, it is difficult to passivate conventional 156cm×156cm or 125cm×125cm solar cells, such as chemical or plasma etching and PECVD. After dicing, the solar cells are uniformly passivated to reduce efficiency loss after dicing

[0004] At present, the cutting of solar cells generally uses a laser or a diamond blade (mechanically) to cut through the entire solar cell from the front or back of the larger solar cell, so as to obtain a solar cell of the required shape and size. Due to the thermodynamic loss and the existence of defect impurities at the edges of the cut solar cells, the edges become defect recombination centers for minority carriers, which greatly reduces the efficiency of the solar cells; another cutting method is to use laser or Diamond blade (mechanical method) scribing from the back of the solar cell (that is, the side with the aluminum back field), the scribing depth is one-third to two-thirds of the thickness of the entire solar cell, and then manually or automatically The method of splitting the solar cell from the scribing place has the advantage of less damage and can improve the efficiency loss of the solar cell after cutting, but the disadvantage is that the shape and size of the cut solar cell are not fixed, and Scribing is often required on all sides, so it is difficult to automate chip breaking, so the production efficiency is extremely low

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