Ag electrode paste, solar battery cell, and process for producing the solar battery cell

Abstract

This invention provides an Ag electrode paste for light receiving face-side electrode formation, which can provide a solar battery cell with a high conversion efficiency and provided with a light receiving face-side electrode having low line resistance, and a solar battery cell having good characteristics producing using the Ag electrode paste, and a process for producing the solar battery cell. The Ag electrode paste for use in the formation of a light receiving face-side electrode (10) comprises (a) Ag particles, (b) an organic vehicle, and (c) a lead-free glass frit comprising SiO2: 13 to 17% by weight, B2O3; 0 to 6% by weight, Bi2O3: 65 to 75% by weight, Al2O3: 5% by weight, TiO2: 1 to 3% by weight, and CuO: 0.5 to 2% by weight. The Ag electrode paste is used in the formation of a second electrode in a light receiving face-side electrode (10) comprising a first electrode (11) and a second electrode (12) provided on the first electrode.

Description

Technical field [0001] The present invention relates to an Ag electrode paste, a solar battery cell using the paste to form a light-receiving surface electrode, and a method for manufacturing a solar battery cell provided with a step of forming a light-receiving surface electrode using the Ag electrode paste. Background technique [0002] As a current method of manufacturing solar battery cells, it is disclosed that after forming a PN junction on a semiconductor substrate, a comb-shaped interdigital electrode is formed on at least one main surface of the semiconductor substrate, and a solar cell is connected to a bus bar electrode of the interdigital electrode. A method of manufacturing a battery cell, in which a conductive paste is printed twice and fired to form a two-layer structure bus bar electrode (see Patent Document 1 figure 1 ~ Figure 4). [0003] In the manufacturing method of the solar cell unit, in the two-layered bus bar electrode (Ag electrode in the embodiment) on th...

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Problems solved by technology

[0010] However, as in Patent Document 1 above, in the case of a solar battery cell having two layers of bus bar electrodes (light-receiving surface side electrodes) made of Ag electrodes, the glass frit contained in the Ag electrode paste for forming the upper layer bus bar electrodes is Flows on the surface of the bus bar electrode on the upper layer side during electrode firing, for example, in the case of welding lead wires to the bus bar electrode on the upper layer side, there is a problem that the weld wettability is hindered

[0011] In addition, when the glass frit contained in the Ag electrode paste for forming the bus bar electrode on the upper layer side flows too much to the bus bar electrode on the lower layer side, the ohmic contact between the bus bar electrode on the lower layer side and the Si substrate is hindered, and the solar battery cell Conversion efficiency may decrease

[0012] Furthermore, there is a problem that, when the Ag electrode paste is fired, the bus bar electrodes on the upper layer will be damaged before the gas (decomposed gas of binder, combustion gas, etc.) generated from the bus bar electrodes (Ag electrodes) on the lower layer side is exhausted When the sintering is completed, bubbles are generated due to the above-mentioned gas

[0013] In addition, the electrode paste of Patent Document 2 relates to an Ag / Al electrode, which does not provide useful information on the lead-free glass frit used in the Ag electrode paste used in this application, and is used as the light-receiving surface side electrode of the solar cell unit. In the case of forming an Ag electrode, the method of obtaining a solar cell unit with better characteristics is not indicated in Patent Document 2.

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