Lead free glass frit powder for manufacturing silicon solar cell, its producing method, metal paste composition containing the same and silicon solar cell

Abstract

Disclosed are lead free glass frit powder for manufacturing a silicon solar cell, its producing method, a metal paste composition containing the same and a silicon solar cell. The lead free glass frit powder for manufacturing a silicon solar cell includes Bi 2 O 3 ; B 2 O 3 ; and any one metal oxide selected from the group consisting of ZnO, Al 2 O 3 and BaCO 3 , or mixtures thereof. The glass frit powder is free of lead, and thus, it is environmental friendly. A front electrode of a solar cell formed using the glass frit powder has low resistance against contact with a substrate and high adhesion to the substrate.

1 . Lead free glass frit powder for manufacturing a silicon solar cell, comprising:
 Bi 2 O 3 ;   B 2 O 3 ; and   any one metal oxide selected from the group consisting of ZnO, Al 2 O 3  and BaCO 3 , or mixtures thereof.   
     
     
         2 . The lead free glass frit powder for manufacturing a silicon solar cell according to  claim 1 ,
 wherein the glass frit powder comprises 75 to 95 weight % of the Bi 2 O 3 , 1 to 15 weight % of the B 2 O 3 , and 1 to 20 weight % of any one metal oxide selected from the group consisting of ZnO, Al 2 O 3  and BaCO 3 , or mixtures thereof.   
     
     
         3 . The lead free glass frit powder for manufacturing a silicon solar cell according to  claim 1 ,
 wherein the glass frit powder has an average particle size of 1 to 10 μm (micrometer).   
     
     
         4 . A producing method of lead free glass frit powder for manufacturing a silicon solar cell, comprising:
 (S 1 ) preparing constituents to produce glass frit powder, including Bi 2 O 3 ; B 2 O 3 ; and   any one metal oxide selected from the group consisting of ZnO, Al 2 O 3  and BaCO 3 , or mixtures thereof;   (S 2 ) melting the prepared constituents together;   (S 3 ) cooling the melted mixture to form glass frit in a solid phase; and   (S 4 ) pulverizing the solid-phase glass frit into a powder phase.   
     
     
         5 . The producing method of lead free glass frit powder for manufacturing a silicon solar cell according to  claim 4 ,
 wherein, in the step (S 1 ), the glass frit powder comprise 75 to 95 weight % of the Bi 2 O 3 , 1 to 15 weight % of the B 2 O 3 , and 1 to 20 weight % of any one metal oxide selected from the group consisting of ZnO, Al 2 O 3  and BaCO 3 , or mixtures thereof.   
     
     
         6 . The producing method of lead free glass frit powder for manufacturing a silicon solar cell according to  claim 4 ,
 wherein the melting process of the step (S 2 ) has a melting temperature of 900 to 1500° C.   
     
     
         7 . The producing method of lead free glass frit powder for manufacturing a silicon solar cell according to  claim 4 ,
 wherein the cooling process of the step (S 3 ) has a cooling temperature of 25 to 50° C.   
     
     
         8 . The producing method of lead free glass frit powder for manufacturing a silicon solar cell according to  claim 4 ,
 wherein the pulverizing process of the step (S 4 ) is a dry or wet pulverizing process.   
     
     
         9 . The producing method of lead free glass frit powder for manufacturing a silicon solar cell according to  claim 4 ,
 wherein glass frit powder obtained by the pulverizing process of the step (S 4 ) has an average particle size of 1 to 10 μm (micrometer).   
     
     
         10 . A metal paste composition for forming a front electrode of a silicon solar cell, comprising:
 silver powder;   glass frit powder; and   an organic binder,   wherein the glass frit powder is defined in  claim 1 .   
     
     
         11 . The metal paste composition for forming a front electrode of a silicon solar cell according to  claim 10 ,
 wherein the glass frit powder is included at an amount of 1 to 20 parts by weight based on 100 parts by weight of the silver powder.   
     
     
         12 . A silicon solar cell, comprising:
 a silicon semiconductor substrate;   an emitter layer formed on the substrate;   an anti-reflection film formed on the emitter layer;   a front electrode penetrating through the anti-reflection film and connected with the emitter layer; and   a rear electrode connected with a rear surface of the substrate,   
       wherein the front electrode is formed by applying the metal paste composition defined in  claim 10  on the anti-reflection film at a predetermined pattern, and sintering the metal paste composition.