Electrically conductive paste for front electrode of solar cell and preparation method thereof

Abstract

The present invention provides an electrically conductive paste for a front electrode of a solar cell and a preparation method thereof. The electrically conductive paste is composed of a corrosion binder, a metallic powder and an organic carrier. The corrosion binder is one or more glass-free Pb—Te based crystalline compounds having a fixed melting temperature in a range of 440° C. to 760° C. During a sintering process of the electrically conductive paste for forming an electrode, the corrosion binder is converted into a liquid for easily corroding and penetrating an antireflective insulating layer on a front side of the solar cell, so that a good ohmic contact is formed. At the same time, the electrically conductive metallic powder is wetted, and the combination of the metallic powder is promoted. As a result, a high-conductivity front electrode of a crystalline silicon solar cell is formed.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application claims priority to a PCT Application No. PCT / CN2013 / 073098, filed on Mar. 22, 2013, commonly assigned and incorporated as reference for all purposes.[0002]The subject matter of the present application is related to China Patent Application No. 201210360864.5, filed on Sep. 25, 2012, by Ran Guo, U.S. patent application Ser. No. 13 / 730,939, filed on Dec. 28, 2012, by Ran Guo, and U.S. patent application Ser. No. 13 / 787,997, filed on Mar. 7, 2013, by Xiaoli Liu et al., commonly assigned and incorporated by reference herein to their entireties for all purposes.BACKGROUND OF THE INVENTION[0003]The present invention relates to the technical field of solar cells, and more particularly to an electrically conductive paste for a front electrode of a solar cell and a preparation method thereof.[0004]Solar energy is an inexhaustible source of clean energy. With the increasing depletion of coal, oil and other non-renewable energy, de...

AI Technical Summary

Benefits of technology

The present invention improves an electrically conductive paste used for the manufacture of electrodes on semiconductor surfaces. The paste uses a full-crystal corrosion binder free of any glass material as a binding additive. The binder is prepared with selective weight ratios and crystal particle sizes, and the metallic powder and organic carrier are mixed in a specific way. This allows the conductive paste to form electrodes on solar cells with better metal-semiconductor electrical contact and reduced series resistance, leading to enhanced photovoltaic conversion efficiency. The method of making the conductive paste is simple and cost-effective.

Problems solved by technology

Solar energy is an inexhaustible source of clean energy.

In the selection of the glass frit, the composition, softening point, thermal expansion coefficient, wetting properties and amount will affect the physical and chemical changes in the sintering process, thereby affecting the performance of the solar cell.

If the content of the glass frit is low, full contact and complete reaction of the glass frit and the antireflective layer cannot be ensured.

The higher the amount of the glass frit is, the lower the relative content of the electrically conductive metallic phase is, and the lower the probability of contact of metallic particles is, resulting in serious deterioration of conductivity.

But excessively-early softening of the glass frit can clog the communicating pores in the metallic powder, thereby hindering the effective discharge of the organic carrier.

However, regardless the use of various glass frit materials, due to restrictions of the physical properties of the glass frit, the above technical problems still exist, resulting in process difficulties with narrow windows in preparation of a suitable glass frit and a subsequent conductive paste.

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