SILVER PASTE FOR SOLAR CELL AND METHOD FOR MAKING SAME

• US 20170117422A1
• Filed: 12/28/2015
• Published: 04/27/2017
• Est. Priority Date: 10/26/2015
• Status: Abandoned Application

• Current Assignee: Hon Hai Precision Industry Co., Ltd., Kang Zhun Electronical Technology (Kunshan) Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd., Kang Zhun Electronical Technology (Kunshan) Co., Ltd.
• Inventors: CHANG, HSIN-PEI, CHEN, WEN-RONG, JANG, GUH-YAW, XU, DI, ZHAO, XUE-QUAN, WANG, DENG, HE, SONG-SONG, KE, CHAO
• Application Number:
  US14/980,855
• Publication Number:
  US 20170117422A1
• Time in Patent Office: Days
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A silver paste includes silver powder having a weight percentage of about 39% to about 60%, organic carrier having a weight percentage of about 35% to about 60%; and inorganic glass phase having a weight percentage of about 1% to about 5%. The inorganic glass phase includes a primary glass phase and inorganic additives. The primary glass phase includes bismuth oxide having a weight percentage of 10% to 40% in the inorganic glass phase, aluminum oxide having a weight percentage of 20% to 60% in the inorganic glass phase, and silicon oxide having a weight percentage of 10% to 30% in the inorganic glass phase.

Claims

1. A silver paste comprising:

silver powder having a weight percentage of about 39% to about 60%;

organic carrier having a weight percentage of about 35% to about 60%; and

inorganic glass phase having a weight percentage of about 1% to about 5%, the inorganic glass phase comprising a primary glass phase and inorganic additives, the primary glass phase comprising bismuth oxide having a weight percentage of about 10% to about 40% in the inorganic glass phase, aluminium oxide having a weight percentage of about 20% to about 60% in the inorganic glass phase, and silicon oxide having a weight percentage of about 10% to about 30% in the inorganic glass phase;

the inorganic additives comprising at least two selected from a group consisting of copper oxide, zinc oxide, titanium oxide, manganese oxide, antimony oxide, magnesium oxide, lithium oxide, tin oxide, and nickel oxide.

2. The silver paste of claim 1, wherein in the inorganic glass phase, the copper oxide has a weight percentage of about 0% to about 10%, the zinc oxide has a weight percentage of about 0% to about 40%, the titanium oxide has a weight percentage of about 0% to about 5%, the manganese oxide has a weight percentage of about 0% to about 10%, the antimony oxide has a weight percentage of about 0% to about 1%, the magnesium oxide has a weight percentage of about 0% to about 5%, the tin oxide has a weight percentage of about 0% to about 5%, the lithium oxide has a weight percentage of about 0% to about 5%, and the nickel oxide has a weight percentage of about 0% to about 5%.

3. The silver paste of claim 1, wherein particles of the silver powder is flake-shaped or spherical.

4. The silver paste of claim 1, wherein the silver powder has a particle size in the range from 0.1 to 5 μ

m.

5. The silver paste of claim 4, wherein silver powder having a particle size in the range from 0.1 to 1 μ

m has a weight percentage of about 10% to about 30%, and silver powder having a particle size in the range from 1 to 5 μ

m has a weight percentage of about 70% to about 90%.

6. The silver paste of claim 1, wherein the organic carrier comprises organic resin, solvent, defoamer agent, plasticizer, surfactant and thixotropic agent.

7. The silver paste of claim 6, wherein in the organic carrier, the organic resin has a weight percentage of about 8% to about 30%, the solvent has a weight percentage of about 60% to about 85%, the defoamer agent has a weight percentage of about 0.5% to about 1%, the plasticizer has a weight percentage of about 1% to about 5%, the surfactant has a weight percentage of about 0.5% to about 2%, the thixotropic agent has a weight percentage of about 0.5% to about 2%.

8. The silver paste of claim 6, wherein the organic resin comprises at least one selected from a group consisting of hydroxyethyl cellulose, acetyl butyryl cellulose, phenolic resin, and phenolic epoxy resin;

the solvent comprises at least one selected from a group consisting of alpha-terpineol, ethelene glycol monophenyl ether, and diethylene glycol monobutyl ether;

the defoamer agent comprises at least one selected from a group consisting of silicone oil and modified polyether;

the plasticizer comprises at least one selected from a group consisting of tributyl citrate, dimethyl phthalate, and 2-(2-butoxyethoxy)-ethanol acetate;

the surfactant comprises at least one selected from a group consisting of lecithin, polyoxyethylene sorbitan fatty acid ester and polyether;

the thixotropic agent comprises at least one selected from a group consisting of polyamide wax and castor oil hydrogenated.

9. The silver paste of claim 1, wherein the silver paste has a fineness of less than 10 μ

m and a viscosity of about 20000 to about 50000 mpa·

s.

10. A method for making a silver paste comprising:

mixing silver powder, inorganic glass phase and organic carrier together to obtain a mixture, the silver powder having a weight percentage of about 39% to about 60% in the mixture, the organic carrier having a weight percentage of about 35% to about 60% in the mixture; and

the inorganic glass phase having a weight percentage of about 1% to about 5% in the mixture, the inorganic glass phase comprising a primary glass phase and inorganic additives, the primary glass phase comprising bismuth oxide having a weight percentage of about 10% to about 40% in the inorganic glass phase, aluminium oxide having a weight percentage of about 20% to about 60% in the inorganic glass phase, and silicon oxide having a weight percentage of about 10% to about 30% in the inorganic glass phase;

the inorganic additives comprising at least two selected from a group consisting of copper oxide, zinc oxide, titanium oxide, manganese oxide, antimony oxide, magnesium oxide, lithium oxide, tin oxide, and nickel oxide;

stirring and grinding the mixture to form the silver paste.

11. The method of claim 10, wherein the organic carrier is made by at least following steps:

mixing organic resin, solvent, defoamer agent, plasticizer, surfactant and thixotropic agent together to form an organic mixture;

heating the organic mixture to a temperature of about 80 to about 120°

C. and stirring the organic mixture to be a uniform fluid.

12. The method of claim 11, wherein in the organic mixture, the organic resin has a weight percentage of about 8% to about 30%, the solvent has a weight percentage of about 60% to about 85%, the defoamer agent has a weight percentage of about 0.5% to about 1%, the plasticizer has a weight percentage of about 1% to about 5%, the surfactant has a weight percentage of about 0.5% to about 2%, the thixotropic agent has a weight percentage of about 0.5% to about 2%.

13. The method of claim 11, wherein the organic resin comprises at least one selected from a group consisting of hydroxyethyl cellulose, acetyl butyryl cellulose, phenolic resin, and phenolic epoxy resin;

the solvent comprises at least one selected from a group consisting of alpha-terpineol, ethelene glycol monophenyl ether, and diethylene glycol monobutyl ether;

the defoamer agent comprises at least one selected from a group consisting of silicone oil and modified polyether;

the plasticizer comprises at least one selected from a group consisting of tributyl citrate, dimethyl phthalate, and 2-(2-butoxyethoxy)-ethanol acetate;

the surfactant comprises at least one selected from a group consisting of lecithin, polyoxyethylene sorbitan fatty acid ester and polyether;

the thixotropic agent comprises at least one selected from a group consisting of polyamide wax and castor oil hydrogenated.

14. The method of claim 10, wherein in the inorganic glass phase, the copper oxide has a weight percentage of about 0% to about 10%, the zinc oxide has a weight percentage of about 0% to about 40%, the titanium oxide has a weight percentage of about 0% to about 5%, the manganese oxide has a weight percentage of about 0% to about 10%, the antimony oxide has a weight percentage of about 0% to about 1%, the magnesium oxide has a weight percentage of about 0% to about 5%, the tin oxide has a weight percentage of about 0% to about 5%, the lithium oxide has a weight percentage of about 0% to about 5%, and the nickel oxide has a weight percentage of about 0% to about 5%.

15. The method of claim 10, wherein the silver powder has a particle size in the range from 0.1 to 5 μ

m, silver powder having a particle size in the range from 0.1 to 1 μ

m has a weight percentage of about 10% to about 30%, and silver powder having a particle size in the range from 1 to 5 μ

m has a weight percentage of about 70% to about 90%.