KR101089018B1 - Method for formation front electrode of solar cell - Google Patents

Abstract

PURPOSE: A front electrode formation method of a solar battery is provided to minimize serial resistance and increase a short-circuit current at the same time by maximizing light absorption, thereby improving the photoelectric conversion efficiency of the solar battery. CONSTITUTION: A solar cell substrate(201) is prepared. A first electrode printing layer(202), a second electrode printing layer(203), and a third electrode printing layer(204) are successively coated on the substrate. A front electrode is arranged by firing the first to third electrode printing layers. The width of the second electrode printing layer is 50 to 80 percent of the width of the first electrode printing layer. The width of the third electrode printing layer is 50 to 80 percent of the width of the second electrode printing layer.

Description

Method for formation front electrode of solar cell

The present invention relates to a method for forming a front electrode of a solar cell, and more particularly, to increase the aspect ratio of an electrode to minimize the electrode area and to prevent the increase of electrode resistance, thereby improving the electrical characteristics of the solar cell. A method of forming a front electrode of a battery.

A solar cell is a key element of photovoltaic power generation that converts sunlight directly into electricity, and is basically a diode composed of a p-n junction. In the process of converting sunlight into electricity by solar cells, when solar light is incident on the pn junction of solar cells, electron-hole pairs are generated, and electrons move to n layers and holes move to p layers by the electric field. Photovoltaic power is generated between the pn junctions, and when a load or a system is connected to both ends of the solar cell, current flows to generate power.

Referring to the structure of the solar cell, as shown in FIG. 1, an n-type semiconductor layer 102 is provided on the p-type semiconductor layer 101, and an upper portion of the n-type semiconductor layer 102 and a p-type semiconductor layer are provided. The front electrode 104 and the rear electrode 105 are provided at the bottom, respectively. In this case, the p-type semiconductor layer 101 and the n-type semiconductor layer 102 is implemented in one substrate, the lower portion of the substrate is a p-type semiconductor layer 101, the upper portion of the substrate is an n-type semiconductor layer 102 In general, an n-type semiconductor layer 102 is formed by implanting and diffusing n-type impurity ions around a p-type silicon substrate in a state where a p-type silicon substrate is prepared. In addition, an anti-reflection film 103 is provided on the n-type semiconductor layer 102 to minimize surface reflection. Reference numeral 106 in FIG. 1 denotes a rear electric field layer, and 107 denotes an isolation trench.

On the other hand, electrical losses generated in the solar cell are classified into electrode resistance loss, contact resistance loss between the electrode and the semiconductor layer, semiconductor layer resistance loss. Among these, electrode resistance loss means resistance of the electrode itself, and is inversely proportional to the electrode area in the direction in which electrons move. If the electrode area is small, the series resistance (Rs) is increased, and the fill factor, a parameter representing the characteristics of the solar cell, is reduced, which adversely affects efficiency. Therefore, in order to reduce the electrode resistance loss, the electrode width should be increased by increasing the line width of the electrode and increasing the thickness thereof. However, if the line width of the electrode is made large, the area occupied by the electrode on the surface of the substrate is increased, thereby reducing the area receiving light.

The present invention has been made to solve the above problems, to minimize the electrode area by increasing the aspect ratio of the electrode and to prevent the increase of the electrode resistance of the solar cell to improve the electrical characteristics of the solar cell The object is to provide a method for forming an electrode.

Method for forming a front electrode of a solar cell according to the present invention for achieving the above object comprises the steps of preparing a solar cell substrate, the first electrode printing layer, the second electrode printing layer and the third electrode printing layer on the substrate Sequentially applying and firing the first to third electrode print layers to form a front electrode, wherein the width of the second electrode print layer is the width of the first electrode print layer. 50 to 80% of the width of the third electrode printing layer is characterized in that 50 to 80% of the width of the second electrode printing layer.

The first electrode print layer to the third electrode print layer may be applied through a screen printing method.

The method of forming a front electrode of a solar cell according to the present invention has the following effects.

As the front electrode of the solar cell is composed of triple layers by screen printing, the line width can be reduced, thereby maximizing the absorption of light, increasing the short circuit current, and minimizing the series resistance, thereby improving the photoelectric conversion efficiency of the solar cell. It can be improved.

1 is a configuration diagram of a typical solar cell.
2A to 2C are cross-sectional views illustrating a method of forming a front electrode of a solar cell according to an embodiment of the present invention.

In the present invention, in forming the front electrode through screen printing, the electrode printing layer constituting the front electrode is composed of triple layers, and the electrode printing layer is minimized by reducing the width of the electrode printing layer toward the upper layer, thereby incidence of sunlight. The rate is characterized by maximizing. Hereinafter, a method of forming a front electrode of a solar cell according to an embodiment of the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 2A, a solar cell substrate 201 is prepared. Although not shown in the drawings, irregularities are formed on the entire surface of the substrate 201 by texturing, and a semiconductor layer is formed at a predetermined depth along the circumference of the substrate 201, and is reflected on the entire surface of the substrate 201. The prevention film may be formed in advance.

In this state, the front electrode 205 forming process is performed as shown in FIG. 2B. Specifically, the first electrode printing layer 202 is coated on the substrate 201 through a screen printing method. The first electrode printing layer 202 may be made of aluminum paste. Thereafter, a second electrode printing layer 203 is coated on the first electrode printing layer 202. At this time, the width of the second electrode printing layer 203 is 50 to 80% of the width of the first electrode printing layer 202. Subsequently, the third electrode print layer 204 is formed by screen printing on the second electrode print layer 203, and the width of the third electrode print layer 204 is equal to that of the second electrode print layer 203. 50-80% of the width. The width of the electrode printed layer coated on the upper layer is 50 to 80% of the width of the lower electrode printed layer in order to allow the upper electrode printed layer to be stably applied.

In the state where the first to third electrode printing layers 202, 203, and 204 are screen printed through the above process, when the firing process is performed at a predetermined temperature, a front electrode composed of triple electrode printing layers ( 205) is completed (see FIG. 2C).

201: solar cell substrate 202: first electrode printing layer
203: second electrode print layer 204: third electrode print layer
205: front electrode

Claims (2)

Preparing a solar cell substrate;
Sequentially applying a first electrode printing layer, a second electrode printing layer, and a third electrode printing layer on the substrate; And
And firing the first to third electrode print layers to form a front electrode.
The width of the second electrode printing layer is 50 to 80% of the width of the first electrode printing layer, the width of the third electrode printing layer is characterized in that 50 to 80% of the width of the second electrode printing layer. Method of forming a front electrode of a solar cell.
The method of claim 1, wherein the first to third electrode print layers are applied through a screen printing method.

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