US20200388714A1 - Front-side conductive paste for crystalline silicon solar cell, preparation method therefor, and solar cell - Google Patents

Front-side conductive paste for crystalline silicon solar cell, preparation method therefor, and solar cell Download PDF

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US20200388714A1
US20200388714A1 US17/002,908 US202017002908A US2020388714A1 US 20200388714 A1 US20200388714 A1 US 20200388714A1 US 202017002908 A US202017002908 A US 202017002908A US 2020388714 A1 US2020388714 A1 US 2020388714A1
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etching agent
oxide etching
parts
solar cell
crystalline silicon
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US10868201B1 (en
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Xiaoli Liu
Fengzhen Sun
Yu Li
Delin Li
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Soltrium Advanced Materials Technology Ltd Shenzhen
Soltrium Advanced Materials Technology Ltd Suzhou
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Soltrium Advanced Materials Technology Ltd Shenzhen
Soltrium Advanced Materials Technology Ltd Suzhou
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20Conductive material dispersed in non-conductive organic material
    • H01B1/22Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05DPROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/12Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
    • B22F1/0074
    • BPERFORMING OPERATIONS; TRANSPORTING
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    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • BPERFORMING OPERATIONS; TRANSPORTING
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    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B22F1/107Metallic powder containing lubricating or binding agents; Metallic powder containing organic material containing organic material comprising solvents, e.g. for slip casting
    • BPERFORMING OPERATIONS; TRANSPORTING
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    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • B22F7/08Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41MPRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M3/00Printing processes to produce particular kinds of printed work, e.g. patterns
    • B41M3/006Patterns of chemical products used for a specific purpose, e.g. pesticides, perfumes, adhesive patterns; use of microencapsulated material; Printing on smoking articles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41MPRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M7/00After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock
    • B41M7/009After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock using thermal means, e.g. infrared radiation, heat
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C32/00Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/001Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
    • C22C32/0015Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
    • HELECTRICITY
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    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/14Conductive material dispersed in non-conductive inorganic material
    • H01B1/16Conductive material dispersed in non-conductive inorganic material the conductive material comprising metals or alloys
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0224Electrodes
    • H01L31/022408Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • H01L31/068Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2301/00Metallic composition of the powder or its coating
    • B22F2301/25Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru
    • B22F2301/255Silver or gold
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2302/00Metal Compound, non-Metallic compound or non-metal composition of the powder or its coating
    • B22F2302/25Oxide
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10Processes characterised by the sequence of their steps
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0216Coatings
    • H01L31/02161Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02167Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H01L31/02168Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells the coatings being antireflective or having enhancing optical properties for the solar cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/547Monocrystalline silicon PV cells

Definitions

  • the present invention relates to the technical field of solar cells, and particularly, to a front-side conductive paste for a crystalline silicon solar cell, a preparation method therefor, and a solar cell.
  • Solar energy is an inexhaustible and clean energy source. With the depletion of non-renewable energy sources such as coal and petroleum, the development and utilization of solar energy has become a hot spot. Solar cells developed based on this idea are an important means of utilizing solar energy. At present, the industrialized crystalline silicon solar cell has become a model for use of solar cells.
  • Cell chip is a core component in the crystalline silicon solar cell.
  • an electrode In order to collect and guide the current generated under illumination, an electrode needs to be fabricated respectively on each of a light-receiving front side and a back side of the cell chip.
  • a conductive paste is applied to a silicon cell chip by screen printing, and a front-side electrode is formed on the front side of the silicon cell chip by sintering.
  • the sintered front-side electrode of the crystalline silicon solar cell needs to be firmly adhered onto the silicon cell chip, has narrow and high grid lines and small light shielding area, and is easy to be soldered.
  • the conductive paste for the front-side electrode of the silicon solar cell is required to have the ability to penetrate a silicon nitride anti-reflective film during the sintering process, to form a good ohmic contact with the silicon cell chip.
  • a common front-side conductive paste for the crystalline silicon solar cell contains a silver powder, a glass powder, and an organic carrier, and the conductive paste is sintered to form a front-side electrode.
  • an oxide etching agent in the conductive paste etches and penetrates an anti-reflective insulating layer such as silicon nitride, titanium oxide, aluminum oxide, silicon oxide, or silicon oxide/titanium oxide on the front side or the side of irradiation of the crystalline silicon solar cell, so that the silver powder is brought into contact with the substrate of the crystalline silicon solar cell to form a front-side electrode.
  • the conventional front-side conductive paste and the glass powder used cannot well etch the anti-reflective insulating layer on the surface of the silicon solar cell chip, and the contact resistance between the front-side electrode formed and the surface of the silicon solar cell chip is high, thus affecting the photoelectric conversion efficiency of the silicon solar cell chip.
  • the technical problem to be solved by the present invention is to provide a front-side conductive paste for a crystalline silicon solar cell and a preparation method therefor, to solve the problem that the existing front-side conductive paste cannot effectively etch the anti-reflective insulating layer on a surface of a silicon chip of the solar cell, causing an increased contact resistance between the front-side electrode and the surface of the silicon chip, and finally a lowered photoelectric conversion efficiency of the silicon chip.
  • the present invention also provides a method for fabricating a front-side electrode of a crystalline silicon solar cell and a silicon solar cell having the front-side electrode. To achieve the above object, the following technical solution is adopted in the present invention.
  • the present disclosure provides a front-side conductive paste for a crystalline silicon solar cell.
  • the conductive paste includes, based on 100 parts by weight, metal powder 80.0-93.0 parts, organic carrier 6.0-15.0 parts, and oxide etching agent 1.0-5.0 parts. Additionally, based on 100% by mole of the oxide etching agent, the oxide etching agent includes 15-30% of PbO; 25-40% of TeO 2 ; 8.0-15.0% of Li 2 O; 9.0-20.0% of SiO 2 ; 5.0-15.0% of Bi 2 O 3 ; 0.5-10.0% of ZnO, and either one or both of 0.1-10.0% of MgO and 0.1-10.0% of CaO.
  • the conductive paste further includes no more than 5.0% of an oxide of an additional oxide element including titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
  • an oxide of an additional oxide element including titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
  • the present disclosure provides a method for preparing a front-side conductive paste for a crystalline silicon solar cell.
  • the method includes a step of melting raw material components of an oxide etching agent to obtain a melted oxide etching agent, a step of quenching the melt to obtain a particulate oxide etching agent, and a step of crushing to obtain a powdered oxide etching agent having a particle size ranging from 0.1 to 5.0 ⁇ m.
  • the method includes a step of mixing raw materials of an organic carrier in an environment of 40-100° C., to obtain the organic carrier.
  • the method includes a step of mixing a metal powder with the powdered oxide etching agent and the organic carrier, to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • the present disclosure provides a method for fabricating a front-side electrode of a crystalline silicon solar cell.
  • the method includes at least the steps of providing a crystalline silicon substrate having an insulating film overlaid on its surface, printing a front-side conductive paste for a crystalline silicon solar cell as described above on a surface of the insulating film, then drying, sintering, and cooling to obtain a front-side electrode of a crystalline silicon solar cell.
  • a crystalline silicon solar cell has a front-side electrode of a crystalline silicon solar cell as described above.
  • the crystalline silicon solar cell includes a crystalline silicon substrate and at least one insulation film overlaid on the crystalline silicon substrate.
  • the crystalline silicon solar cell further includes a front-side electrode in contact with the at least one insulation film and in electrical contact with the crystalline silicon substrate with a square resistance more than 90 ohms.
  • the front-side electrode includes an electrically conductive metal powder, metal oxides of Pb, Te, Li, Bi, Si, Bi, and at least 0.5-10% ZnO, and either one or both of 0.1-10% MgO and 0.1-10% CaO based on 100% mole of the metal oxides.
  • the front-side conductive paste for a crystalline silicon solar cell provided in the present invention has the following advantages.
  • the oxide etching agent contains components of particular ratios, and these components of particular ratios exhibit excellent dissolving and etching properties. Therefore, the oxide etching agent can dissolve a sufficient amount of silver during the sintering process.
  • One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles, which allows the metal powder to form a good ohmic contact with silicon, thus greatly reducing the resistance of the front-side electrode. Finally, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is obtained.
  • the method for preparing a front-side conductive paste for a crystalline silicon solar cell provided in the present invention has simple process conditions, and the obtained front-side conductive paste has uniform components and good performance, and is suitable for mass industrial production.
  • the method for preparing a front-side electrode of a crystalline silicon solar cell provided in the present invention has the following advantages.
  • the front-side conductive paste for a crystalline silicon solar cell provided above is employed, and the oxide etching agent can dissolve a sufficient amount of silver during the sintering process.
  • One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder.
  • the other portion flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • the crystalline silicon solar cell provided in the invention employs the above-mentioned front-side electrode structure, the solar cell structure exhibits good adhesion; and the silver electrode has good ohmic contact with the silicon chip of the solar cell, so that the conversion efficiency of the solar cell is improved.
  • FIG. 1 is a schematic flowchart of a method for preparing a front-side conductive paste for a crystalline silicon solar cell provided in the present disclosure.
  • FIG. 2 is a schematic flowchart of a method for fabricating a front-side electrode of a crystalline silicon solar cell provided in the present disclosure.
  • FIG. 3 is a schematic diagram showing a crystalline silicon substrate having a surface provided with an insulating film, on which a front-side conductive paste according to the present disclosure is printed.
  • FIG. 4 is a schematic diagram showing the sintered crystalline silicon substrate printed with a front-side and a back-side paste shown in FIG. 3 in the present disclosure.
  • FIG. 5 is an exemplary electro microscopic image showing front-side electrode forming good contact with silicon according to an embodiment of the present disclosure.
  • FIG. 6 is a schematic diagram showing a tensile test at 180 degrees.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder of 80.0-93.0 parts, organic carrier of 6.0-15.0 parts, and oxide etching agent of 1.0-5.0 parts.
  • the metal powder of 80.0-83.0 parts is used.
  • the metal powder of 83.0-86.0 parts is used.
  • the metal powder of 86.0-89.0 parts is used.
  • the metal powder of 89.0-91.5 parts is used.
  • the metal powder of 91.5-93.0 parts is used.
  • the organic carrier of 6.0-7.0 parts is used.
  • the organic carrier of 7.0-8.5 parts is used.
  • the organic carrier of 8.5-10.0 parts is used.
  • the organic carrier of 10.0-11.0 parts is used.
  • the organic carrier of 11.0-12.0 parts is used.
  • the organic carrier of 12.0-13.0 parts is used.
  • the organic carrier of 13.0-15.0 parts is used.
  • the oxide etching agent of 1.0-2.0 parts is used.
  • the oxide etching agent of 2.0-3.0 parts is used.
  • the oxide etching agent of 3.0-4.0 parts is used.
  • the oxide etching agent of 4.0-5.0 parts is used.
  • the oxide etching agent includes at least 0.1-10% of MgO, 15-30% of PbO, 25-40% of TeO, 8-15% of Li 2 O, 0.1-10% of CaO, and 5-15% of Bi 2 O 3 . More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO 2 25-40%; Li 2 O 8.0-15.0%; SiO 2 9.0-20.0%; Bi 2 O 3 5.0-15.0%; MgO 0.1-10.0%; ZnO 0.5-10.0%; CaO 0.1-10.0%; and oxide of additional elements 0-5.0%.
  • the oxide etching agent based on 100% by mole includes 15-17% of PbO.
  • the oxide etching agent based on 100% by mole includes 17-20% of PbO.
  • the oxide etching agent based on 100% by mole includes 20-24% of PbO.
  • the oxide etching agent based on 100% by mole includes 24-26% of PbO.
  • the oxide etching agent based on 100% by mole includes 26-28% of PbO.
  • the oxide etching agent based on 100% by mole includes 28-30% of PbO.
  • the oxide etching agent based on 100% by mole includes 25-30% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 30-33% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 33-36% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 36-38% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 38-40% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 8-9% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-10% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 10-11% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 11-12% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 12-13% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 13-14% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 14-15% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-11% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 11-13% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 13-15% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 15-16% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 16-18% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 18-20% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 5-6% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 6-8% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 8-10% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 10-12% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 12-14% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 14-15% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 0.1-0.2% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.2-0.4% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.4-0.6% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.6-1.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 1.0-2.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 2.0-4.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 4.0-6.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 6.0-10.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO.
  • the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO.
  • the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO.
  • the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO.
  • the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.1-0.2% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.2-0.3% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.3-0.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.5-0.7% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.7-1.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 1.0-2.2% of CaO.
  • the oxide etching agent based on 100% by mole includes 2.2-3.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 3.5-5.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 5.0-6.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 6.5-7.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 7.5-9.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 9.0-10.0% of CaO.
  • the oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein.
  • One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder.
  • the other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder 80.0-93.0 parts; organic carrier 6.0-15.0 parts; and oxide etching agent 1.0-5.0 parts.
  • the metal powder of 80.0-83.0 parts is used.
  • the metal powder of 83.0-86.0 parts is used.
  • the metal powder of 86.0-89.0 parts is used.
  • the metal powder of 89.0-91.5 parts is used.
  • the metal powder of 91.5-93.0 parts is used.
  • the organic carrier of 6.0-7.0 parts is used.
  • the organic carrier of 7.0-8.5 parts is used.
  • the organic carrier of 8.5-10.0 parts is used.
  • the organic carrier of 10.0-11.0 parts is used.
  • the organic carrier of 11.0-12.0 parts is used.
  • the organic carrier of 12.0-13.0 parts is used.
  • the organic carrier of 13.0-15.0 parts is used.
  • the oxide etching agent of 1.0-2.0 parts is used.
  • the oxide etching agent of 2.0-3.0 parts is used.
  • the oxide etching agent of 3.0-4.0 parts is used.
  • the oxide etching agent of 4.0-5.0 parts is used.
  • the oxide etching agent includes at least 0.1-10% of MgO, 15-30% of PbO, TeO 2 25-40%, 8-15% of Li 2 O, and 5-15% of Bi 2 O 3 . More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO 2 25-40%; Li 2 O 8.0-15.0%; SiO 2 9.0-20.0%; Bi 2 O 3 5.0-15.0%; MgO 0.5-10.0%; ZnO 0.5-10.0%; and oxide of additional elements 0-5.0%.
  • the oxide etching agent based on 100% by mole includes 15-17% of PbO.
  • the oxide etching agent based on 100% by mole includes 17-20% of PbO.
  • the oxide etching agent based on 100% by mole includes 20-24% of PbO.
  • the oxide etching agent based on 100% by mole includes 24-26% of PbO.
  • the oxide etching agent based on 100% by mole includes 26-28% of PbO.
  • the oxide etching agent based on 100% by mole includes 28-30% of PbO.
  • the oxide etching agent based on 100% by mole includes 25-30% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 30-33% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 33-36% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 36-38% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 38-40% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 8-9% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-10% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 10-11% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 11-12% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 12-13% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 13-14% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 14-15% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-11% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 11-13% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 13-15% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 15-16% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 16-18% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 18-20% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 5-6% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 6-8% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 8-10% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 10-12% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 12-14% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 14-15% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 0.5-0.6% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.6-0.7% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.7-0.9% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.9-1.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 1.0-2.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 2.0-4.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 4.0-6.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 6.0-10.0% of MgO.
  • the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO.
  • the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO.
  • the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO.
  • the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO.
  • the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO.
  • the oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein.
  • One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder.
  • the other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder 80.0-93.0 parts, organic carrier 6.0-15.0 parts, and oxide etching agent 1.0-5.0 parts.
  • the metal powder of 80.0-83.0 parts is used.
  • the metal powder of 83.0-86.0 parts is used.
  • the metal powder of 86.0-89.0 parts is used.
  • the metal powder of 89.0-91.5 parts is used.
  • the metal powder of 91.5-93.0 parts is used.
  • the organic carrier of 6.0-7.0 parts is used.
  • the organic carrier of 7.0-8.5 parts is used.
  • the organic carrier of 8.5-10.0 parts is used.
  • the organic carrier of 10.0-11.0 parts is used.
  • the organic carrier of 11.0-12.0 parts is used.
  • the organic carrier of 12.0-13.0 parts is used.
  • the organic carrier of 13.0-15.0 parts is used.
  • the oxide etching agent of 1.0-2.0 parts is used.
  • the oxide etching agent of 2.0-3.0 parts is used.
  • the oxide etching agent of 3.0-4.0 parts is used.
  • the oxide etching agent of 4.0-5.0 parts is used.
  • the oxide etching agent includes at least 15-30% of PbO, 25-40% of TeO, 8-15% of Li 2 O, 0.1-10% of CaO, and 5-15% of Bi 2 O 3 . More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO 2 25-40%; Li 2 O 8.0-15.0%; SiO 2 9.0-20.0%; Bi 2 O 3 5.0-15.0%; ZnO 0.5-10.0%; CaO 0.1-10.0%; and oxide of additional elements 0-5.0%.
  • the oxide etching agent based on 100% by mole includes 15-17% of PbO.
  • the oxide etching agent based on 100% by mole includes 17-20% of PbO.
  • the oxide etching agent based on 100% by mole includes 20-24% of PbO.
  • the oxide etching agent based on 100% by mole includes 24-26% of PbO.
  • the oxide etching agent based on 100% by mole includes 26-28% of PbO.
  • the oxide etching agent based on 100% by mole includes 28-30% of PbO.
  • the oxide etching agent based on 100% by mole includes 25-30% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 30-33% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 33-36% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 36-38% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 38-40% of TeO 2 .
  • the oxide etching agent based on 100% by mole includes 8-9% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-10% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 10-11% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 11-12% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 12-13% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 13-14% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 14-15% of Li 2 O.
  • the oxide etching agent based on 100% by mole includes 9-11% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 11-13% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 13-15% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 15-16% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 16-18% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 18-20% of SiO 2 .
  • the oxide etching agent based on 100% by mole includes 5-6% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 6-8% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 8-10% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 10-12% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 12-14% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 14-15% of Bi 2 O 3 .
  • the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO.
  • the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO.
  • the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO.
  • the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO.
  • the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO.
  • the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO.
  • the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO.
  • the oxide etching agent based on 100% by mole includes 0.1-0.2% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.2-0.3% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.3-0.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.5-0.7% of CaO.
  • the oxide etching agent based on 100% by mole includes 0.7-1.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 1.0-2.2% of CaO.
  • the oxide etching agent based on 100% by mole includes 2.2-3.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 3.5-5.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 5.0-6.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 6.5-7.5% of CaO.
  • the oxide etching agent based on 100% by mole includes 7.5-9.0% of CaO.
  • the oxide etching agent based on 100% by mole includes 9.0-10.0% of CaO.
  • the oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein.
  • One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder.
  • the other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • the additional element in the oxide of the additional element is one or two or more of titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
  • the oxide etching agent in the three solutions of the present invention includes not only an oxide prepared by a chemical method and an oxide obtained by a high-temperature treatment, but also a carbonate, a phosphate, and a fluoride containing a cation, etc.
  • the lithium oxide Li 2 O may be replaced by Li 2 CO 3 .
  • the oxide etching agent may be crystalline, amorphous, or a mixture of amorphous and crystalline.
  • the same metal powder and organic carrier may be used.
  • the metal powder is particles of at least one metal element of silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium.
  • the metal powder is silver-coated particles.
  • Each particle is at least one metal element of copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese, coated by a silver layer of a thickness in a range of 10-50 nm.
  • the metal powder is a mixture of a non-silver-coated metal powder and a silver-coated metal powder, where a weight ratio of the non-silver coated metal powder to the silver-coated metal powder is 5/95-95/5.
  • the non-silver-coated metal powder includes at least one metal element of silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium
  • the silver-coated metal powder includes at least one metal element of copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese.
  • Particles of the silver-coated metal powder includes a silver coating with a thickness in a range of 10-200 nm.
  • the organic carrier mentioned in the present invention includes an organic solvent, a polymer, a wetting dispersant, a thixotropic agent, and an additional functional additive.
  • the organic carrier includes 50-95 parts of the organic solvent; 1-40 parts of the polymer; 0.1-10 parts of the wetting dispersant; and 1-20 parts of the thixotropic agent.
  • 50-55 parts of the organic solvent is used.
  • 55-60 parts of the organic solvent is used.
  • 60-71 parts of the organic solvent is used.
  • 71-77 parts of the organic solvent is used.
  • 77-82 parts of the organic solvent is used.
  • based on 100 parts by weight, 82-85 parts of the organic solvent is used.
  • based on 100 parts by weight 85-88 parts of the organic solvent is used.
  • based on 100 parts by weight, 88-90 parts of the organic solvent is used.
  • based on 100 parts by weight, 90-92 parts of the organic solvent is used.
  • based on 100 parts by weight, 92-94 parts of the organic solvent is used.
  • based on 100 parts by weight, 94-95 parts of the organic solvent is used.
  • based on 100 parts by weight, 1-2 parts of the polymer is used.
  • based on 100 parts by weight, 2-3 parts of the polymer is used.
  • based on 100 parts by weight, 3-5 parts of the polymer is used.
  • based on 100 parts by weight 5-8 parts of the polymer is used.
  • based on 100 parts by weight, 8-12 parts of the polymer is used.
  • based on 100 parts by weight, 12-18 parts of the polymer is used.
  • based on 100 parts by weight, 18-25 parts of the polymer is used.
  • based on 100 parts by weight, 25-34 parts of the polymer is used.
  • based on 100 parts by weight, 34-37 parts of the polymer is used.
  • based on 100 parts by weight, 37-40 parts of the polymer is used.
  • based on 100 parts by weight 0.1-0.2 parts of the wetting dispersant is used.
  • based on 100 parts by weight 0.2-0.3 parts of the wetting dispersant is used.
  • based on 100 parts by weight 0.3-0.4 parts of the wetting dispersant is used.
  • based on 100 parts by weight 0.4-0.6 parts of the wetting dispersant is used.
  • based on 100 parts by weight 0.6-0.9 parts of the wetting dispersant is used.
  • based on 100 parts by weight 0.9-1.2 parts of the wetting dispersant is used.
  • based on 100 parts by weight, 1.2-2.2 parts of the wetting dispersant is used.
  • based on 100 parts by weight 2.2-4.2 parts of the wetting dispersant is used.
  • based on 100 parts by weight 4.2-5.5 parts of the wetting dispersant is used.
  • based on 100 parts by weight 5.5-6.5 parts of the wetting dispersant is used.
  • based on 100 parts by weight 6.5-7.8 parts of the wetting dispersant is used.
  • based on 100 parts by weight 7.8-9.0 parts of the wetting dispersant is used.
  • based on 100 parts by weight 9.0-1.0 parts of the wetting dispersant is used.
  • based on 100 parts by weight 1-2 parts of the thixotropic agent is used.
  • based on 100 parts by weight 2-3 parts of the thixotropic agent is used.
  • thixotropic agent based on 100 parts by weight, 3-4 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 4-6 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 6-9 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 9-12 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 12-15 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 15-17 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 17-18 parts of the thixotropic agent is used.
  • based on 100 parts by weight, 18-20 parts of the thixotropic agent is used.
  • the organic solvent is at least one selected from terpineol, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, a dodecanol ester, diethylene glycol butyl ether, triethylene glycol butyl ether, tripropylene glycol methyl ether, a terpene, and other high-boiling point solvents.
  • the polymer is at least one selected from ethyl cellulose, methyl cellulose, cellulose and a derivative thereof, an acrylic resin, an alkyd resin, and a polyester resin.
  • the wetting dispersant is one or two or more selected from a fatty acid (e.g. oleic acid and stearic acid), an amide derivative of a fatty acid (e.g. oleamide, and stearamide), an ester derivative of a fatty acid, polyethylene wax, and polyethylene glycol, which mainly functions to disperse the inorganic powder in the organic carrier.
  • a fatty acid e.g. oleic acid and stearic acid
  • an amide derivative of a fatty acid e.g. oleamide, and stearamide
  • an ester derivative of a fatty acid e.g. oleamide, and stearamide
  • polyethylene wax e.g. oleamide, and stearamide
  • the thixotropic agent is one or two or more selected from a hydrogenated castor oil derivative, polyamide wax, polyurea, and fumed silica, and mainly functions to increase the thixotropy of the paste during the printing process, so that the consistency of the silver paste becomes smaller when sheared during the printing process, and it is easy to perform screen printing; and when the shearing is stopped, the consistency is increased to ensure that the electrode has an excellent aspect ratio.
  • the organic carrier may also include a functional additive in an amount of 0.1-20 parts by weight. Based on 100 parts by weight of the organic carrier, the functional additive optionally includes 0.1-0.2 parts. Optionally, the functional additive includes 0.2-0.3 parts. Optionally, the functional additive includes 0.3-0.5 parts. Optionally, the functional additive includes 0.5-0.7 parts. Optionally, the functional additive includes 0.7-1.0 parts. Optionally, the functional additive includes 1.0-2.0 parts. Optionally, the functional additive includes 2.0-5.0 parts. Optionally, the functional additive includes 5.0-10.0 parts. Optionally, the functional additive includes 10.0-15.0 parts. Optionally, the functional additive includes 15.0-20.0 parts.
  • the functional additive is one or two or more chemical species selected from poly (methylphenyl) siloxane, polyphenylsiloxane, a phthalate (e.g. diethyl phthalate, and dibutyl phthalate), micro-crystalline wax, polydimethylsiloxane, polyvinylbutyral (PVB), a polyether- and polyester-modified organosiloxane, and an alkyl-modified organosiloxane.
  • the additional functional additive may be optionally added, for example, micro-crystalline wax is added to reduce the surface tension, dibutyl phthalate (DBP) is added to improve the flexibility of the paste, and polyvinylbutyral (PVB) is added to improve the adhesion.
  • a method for preparing a front-side conductive paste for a crystalline silicon solar cell according to the present invention includes the following steps:
  • oxide etching agent Raw materials of the oxide etching agent are weighed according to the raw material proportion in any one of the above three solutions and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a oven and heated to 900-1100° C.
  • the melted liquid oxide etching agent is quenched, to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried at a temperature of 60-80° C.; and the dried particulate oxide etching agent is crushed to obtain a powdered oxide etching agent having a particle size of 0.5-5.0 ⁇ m, which is then dried in a drying oven at 80-100° C. to obtain a dried powdered oxide etching agent.
  • the quenching method includes cooling the melted liquid oxide etching agent by pouring it into water at 5-25° C. or cooling in flowing cold air at room temperature, where the temperature of the flowing cold air is at 25° C. or below.
  • the above-mentioned crushing of the particulate oxide etching agent may be performed by ball milling in a ball miller, or by other methods to make the particle size of the oxide etching agent smaller.
  • An alternative method for preparing a front-side conductive paste for a crystalline silicon solar cell according to the present invention is also provided.
  • the oxide etching agent and the metal powder are first mixed to obtain a first mixture, and then the first mixture is mixed with the organic carrier, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • the oxide etching agent and the organic carrier are first mixed to obtain a first mixture, and then the metal powder is added to the first mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • the metal powder and organic carrier are first mixed to obtain a first mixture, and then the oxide etching agent is added to the first mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • the amounts of the metal powder, organic carrier, and oxide etching agent are respectively taken as 100 parts by weight; and 20-60 parts by weight of the metal powder and 20-60 parts by weight of the organic carrier are first mixed to obtain a first mixture, then 40-80 parts by weight of the oxide etching agent is mixed with a part of the organic carrier to obtain a second mixture, and then the first mixture is mixed with the second mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • the present invention further provides a method for fabricating a front-side electrode of a crystalline silicon solar cell.
  • a crystalline silicon substrate has a surface having an insulating film deposited, as shown in FIG. 3 .
  • a crystalline silicon chip 100 having a first surface 101 and a second surface 102 opposing to each other.
  • a P/N junction layer 200 and an insulating film 300 are sequentially and outwardly laminated.
  • a back-side silver paste 500 and a back-side aluminum paste 600 are printed.
  • the insulating film 300 may be deposited with at least one of a silicon nitride film, a titanium oxide film, an aluminum oxide film, and a silicon oxide film.
  • the method for fabricating a front-side electrode of a crystalline silicon solar cell includes at least the following steps:
  • Step S04 A crystalline silicon substrate having an insulating film 300 deposited on its surface is provided.
  • Step S05 A front-side conductive paste 400 for a crystalline silicon solar cell (where 401 is a metal powder, 402 is an organic carrier, and 403 is an oxide etching agent) according to any one of the above solutions is printed on a surface of the insulating film 300 .
  • Step S06 The crystalline silicon substrate treated in the step S05 is sequentially dried, sintered, and cooled to obtain a front-side electrode 700 of a crystalline silicon solar cell.
  • the drying temperature is 80-400° C.
  • the sintering temperature is 700-820° C.
  • the cooling is natural cooling (in flowing air at room temperature).
  • the present invention further provides a crystalline silicon solar cell employing a front-side electrode of a crystalline silicon solar cell as described above.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.0 parts of a silver powder; 9.0 parts of an organic carrier; and 3.0 parts of an oxide etching agent.
  • the oxide etching agent includes: 22% of PbO, 30% of TeO 2 , 9.0% of Li 2 O, 18.0% of SiO 2 , 10.0% of Bi 2 O 3 , 10% of MgO, 0.5% of ZnO, and 0.5% of CaO.
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste for a crystalline silicon solar cell obtained in Example 1 is printed by screen printing on a front side of a silicon substrate of a crystalline silicon solar cell having an insulating film, where a back side of the substrate is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the silicon solar cell is sintered at 770° C. to form a front-side electrode of the crystalline silicon solar cell as shown in FIG. 5 . During the sintering, the organic carrier in the front-side conductive paste is evaporated, the oxide etching agent in the front-side conductive paste is melted to form a liquid to contact with the silver powders, so that a sufficient amount of silver is dissolved therein.
  • liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powders.
  • the other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched.
  • the liquid oxide etching agent is deposited on the silicon substrate A02 as a high-resistivity solid layer (an insulation film), the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles A03 which are distributed in the high-resistivity solid layer of the oxide etching agent, which allow a good ohmic contact to form between metal in the paste with the silicon substrate A02, thus reducing the resistance and enhancing current flow for the silicon solar cell. In this way, a front-side electrode A01 with low contact resistance, good electrical conductivity, and strong adhesion is formed for the silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes: 30% of PbO, 25% of TeO 2 , 15% of Li 2 O, 9.0% of SiO 2 , 5.0% of Bi 2 O 3 , 4.0% of MgO, 2.0% of ZnO, and 10% of CaO.
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps:
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 2 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 25% of PbO, 20.5% of TeO 2 , 13% of Li 2 O, 9.5% of SiO 2 , 12% of Bi 2 O 3 , 3.0% of MgO, 10% of ZnO, and 7.0% of CaO.
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 3 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 780° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 22.9% of PbO, 25% of TeO 2 , 14% of Li 2 O, 15% of SiO 2 , 14% of Bi 2 O 3 , 8.0% of MgO, 0.5% of ZnO, 0.1% of CaO, and 0.5% of Al 2 O 3 .
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 4 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 780° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 25% of PbO, 30% of TeO 2 , 8.0% of Li 2 O, 10% of SiO 2 , 10.0% of Bi 2 O 3 , 6.0% of MgO, 5.5% of ZnO, 5.0% of CaO, and 0.5% of TiO 2 .
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste for a crystalline silicon solar cell obtained in Example 5 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 790° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 24% of PbO, 25% of TeO 2 , 9% of Li 2 O, 15% of SiO 2 , 15% of Bi 2 O 3 , 0.1% of MgO, 0.9% of ZnO, 10% of CaO, 0.5% of Al 2 O 3 , and 0.5% of TiO 2 .
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 6 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 20% of PbO, 25% of TeO 2 , 15% of Li 2 O, 20% of SiO 2 , 9% of Bi 2 O 3 , 0.5% of ZnO, 10% of CaO, and 0.5% of TiO 2 .
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 7 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 21% of PbO, 25% of TeO 2 , 14% of Li 2 O, 10.5% of SiO 2 , 11% of Bi 2 O 3 , 8.0% of MgO, 10% of ZnO, and 0.5% of Al 2 O 3 .
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 8 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 25% of PbO, 26% of TeO 2 , 7% of Li 2 O, 19.5% of SiO 2 , 15% of Bi 2 O 3 , 0.3% of MgO, 7% of ZnO, and 0.2% of CaO.
  • the oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 9 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 25% of PbO, 25% of TeO 2 , 6.0% of Li 2 O, 15% of SiO 2 , 15% of Bi 2 O 3 , 2.0% of MgO, 5.0% of ZnO, 5.0% of CaO, 1.5% of Al 2 O 3 , and 0.5% of TiO 2 .
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 10 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 33% of PbO, 22% of TeO 2 , 4% of Li 2 O, 18% of SiO 2 , 14% of Bi 2 O 3 , 5% of MgO, 3% of ZnO, and 1% of CaO.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 11 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 13.3% of PbO, 39% of TeO 2 , 5% of Li 2 O, 6.6% of SiO 2 , 20% of Bi 2 O 3 , 13% of MgO, 3% of ZnO, and 0.1% of CaO.
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 12 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 770° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 18.8% of PbO, 22% of TeO 2 , 4% of Li 2 O, 16% of SiO 2 , 20% of Bi 2 O 3 , 16% of MgO, 3% of ZnO, and 0.2% of CaO.
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 13 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 17.3% of PbO, 22% of TeO 2 , 4% of Li 2 O, 18.7% of SiO 2 , 4% of Bi 2 O 3 , 16% of MgO, 3% of ZnO, and 15% of CaO.
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 ⁇ m, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 14 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • a front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • the oxide etching agent includes 18.8% of PbO, 22% of TeO 2 , 7% of Li 2 O, 12% of SiO 2 , 20% of Bi 2 O 3 , 0.2% of MgO, 3% of ZnO, and 17% of CaO.
  • the oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • a method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • a method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • the front-side conductive paste obtained in Example 15 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • the front-side conductive paste PVM1B for a crystalline silicon solar cell widely available from the market is printed by screen printing on a front side of a crystalline silicon solar cell having the same insulating film as that in the examples, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered by heating to 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. Then the efficiency of the silicon solar cell chip is tested, and the IV test results are summarized in Table 1.
  • FIG. 6 is a schematic diagram showing a tensile test at 180 degrees. Specifically, a solder strip 800 is first soldered to the surface of a main grid, and then the crystalline silicon cell chip 100 is fixed to a tensile tester 900 by using a first fixing bolt 901 and a second fixing bolt 902 . The tensile test is performed in the direction of the tensile force F. The tensile test results are shown in Table 1.
  • the conversion efficiency of the solar cells of Examples 1-8 is on average 18.46%, which is quite significant over the rate 18.12% achieved by the solar cell of Comparative Example.
  • the conversion rate of Examples 9-15 is lower than that of the solar cell of Comparative Example.
  • the difference in conversion rate of the solar cells is mainly caused by the different oxide etching agents used, because the same silver powder and organic carrier are used in these examples.
  • the series resistance (Rs) of the solar cells of Example 1-8 is ( ⁇ 0.002 Ohms) significantly lower than 0.028 Ohms of the solar cells of Comparative Example. This indicates that the electrical contact formed between the metal element and the silicon substrate or cell chip of the solar cell by applying the conductive paste based on Examples 1-8 over the insulation film on the silicon solar cell chip is significantly improved over the electrical contact by using conventional conductive paste.
  • the oxide etching agents of Examples 1-6 have better performance due to their unique proportions of oxide components, and the molar contents of the oxide are in the following ranges: PbO 15-30%, TeO 2 25-40%, Li 2 O 8-15%, SiO 2 9-20%, Bi 2 O 3 5-15%, MgO 0.1-8%, ZnO 0.5-10.0%, CaO 0.1-10.0%, and oxides of additional elements Al 2 O 3 and TiO 2 0-5.0%.
  • the unique proportions of the oxide components allow the oxide etching agent to dissolve sufficient silver during the sintering process, which can fully etch the insulating layer on the surface of the cell chip without excessively etching the silicon cell chip, so that the silver electrode has not only good ohmic contact with, but also high adhesion to the silicon cell chip.
  • the oxide etching agent of Example 7 contains no MgO, but a amount of CaO, and also has good performance.
  • the oxide etching agent of Example 8 contains no CaO, but a amount of MgO, and also has good performance.
  • the conversion rate of the solar cells of Examples 9-15 is lower than that of Comparative Example.
  • the series resistance (Rs) of the solar cells of Example 9-15 is significantly higher because the molar proportions of the oxides used in the oxide etching agent is not in the optimum range.
  • the oxide etching agent cannot effectively erode the insulating film on the silicon solar cell chip during the sintering process, and the front side silver electrode does not form a good contact with the silicon substrate.
  • a crystalline silicon solar cell includes a crystalline silicon substrate and at least one insulation film deposited on the crystalline silicon substrate.
  • the crystalline silicon solar cell further includes a front-side electrode in contact with the at least one insulation film and in electrical contact with the crystalline silicon substrate characterized by a series resistance no greater than 0.002 Ohms.
  • the front-side electrode includes an electrically conductive metal powder, oxides of several metal elements including Pb, Te, Li, Bi, Si, Bi, at least 0.5-10 wt % ZnO, and either one or both of 0.1-10 wt % MgO and 0.1-10 wt % CaO.

Abstract

A front-side conductive paste for a crystalline silicon solar cell is provided. The front-side conductive paste for a crystalline silicon solar cell includes, in parts by weight, 80.0-93.0 parts of a metal powder, 6.0-15.0 parts of an organic carrier, and 1.0-5.0 parts of an oxide etching agent, where based on 100% by mole of the oxide etching agent, the oxide etching agent includes 15-30% of PbO; 25-40% of TeO2; 8.0-15.0% of Li2O; 9.0-20.0% of SiO2; 5.0-15.0% of Bi2O3; 0.5-10.0% of ZnO; and either one or both of 0.1-10.0% of MgO and 0.1-10.0% of CaO; and no more than 5.0% of an oxide of additional metal elements. The metal powder forms good ohmic contact with crystalline silicon substrate during the sintering process of the front-side conductive paste applied overlying an insulation film on the substrate. Finally, a front-side electrode of low contact resistance, good electrical conductivity, and strong adhesion is obtained.

Description

    CROSS-REFERENCES TO RELATED APPLICATIONS
  • This application is a continuation of and claims priority to U.S. patent application Ser. No. 16/254,977, filed Jan. 23, 2019, which is a continuation in part of and claims priority to PCT Patent Application No. PCT/CN2018/081375, filed on Mar. 30, 2018, commonly assigned and incorporated by reference herein to its entirety for all purposes.
  • BACKGROUND OF THE INVENTION
  • The present invention relates to the technical field of solar cells, and particularly, to a front-side conductive paste for a crystalline silicon solar cell, a preparation method therefor, and a solar cell.
  • Solar energy is an inexhaustible and clean energy source. With the depletion of non-renewable energy sources such as coal and petroleum, the development and utilization of solar energy has become a hot spot. Solar cells developed based on this idea are an important means of utilizing solar energy. At present, the industrialized crystalline silicon solar cell has become a model for use of solar cells.
  • Cell chip is a core component in the crystalline silicon solar cell. In order to collect and guide the current generated under illumination, an electrode needs to be fabricated respectively on each of a light-receiving front side and a back side of the cell chip. There are various methods available for manufacturing electrodes. Among them, screen printing and co-sintering are a currently most common production process. For example, in the manufacture of front-side electrodes, a conductive paste is applied to a silicon cell chip by screen printing, and a front-side electrode is formed on the front side of the silicon cell chip by sintering. The sintered front-side electrode of the crystalline silicon solar cell needs to be firmly adhered onto the silicon cell chip, has narrow and high grid lines and small light shielding area, and is easy to be soldered. The conductive paste for the front-side electrode of the silicon solar cell is required to have the ability to penetrate a silicon nitride anti-reflective film during the sintering process, to form a good ohmic contact with the silicon cell chip.
  • A common front-side conductive paste for the crystalline silicon solar cell contains a silver powder, a glass powder, and an organic carrier, and the conductive paste is sintered to form a front-side electrode. During the sintering process, an oxide etching agent in the conductive paste etches and penetrates an anti-reflective insulating layer such as silicon nitride, titanium oxide, aluminum oxide, silicon oxide, or silicon oxide/titanium oxide on the front side or the side of irradiation of the crystalline silicon solar cell, so that the silver powder is brought into contact with the substrate of the crystalline silicon solar cell to form a front-side electrode.
  • As the sheet resistance of the solar cell increases, the conventional front-side conductive paste and the glass powder used cannot well etch the anti-reflective insulating layer on the surface of the silicon solar cell chip, and the contact resistance between the front-side electrode formed and the surface of the silicon solar cell chip is high, thus affecting the photoelectric conversion efficiency of the silicon solar cell chip.
  • BRIEF SUMMARY OF THE INVENTION
  • The technical problem to be solved by the present invention is to provide a front-side conductive paste for a crystalline silicon solar cell and a preparation method therefor, to solve the problem that the existing front-side conductive paste cannot effectively etch the anti-reflective insulating layer on a surface of a silicon chip of the solar cell, causing an increased contact resistance between the front-side electrode and the surface of the silicon chip, and finally a lowered photoelectric conversion efficiency of the silicon chip.
  • Further, the present invention also provides a method for fabricating a front-side electrode of a crystalline silicon solar cell and a silicon solar cell having the front-side electrode. To achieve the above object, the following technical solution is adopted in the present invention.
  • In an aspect, the present disclosure provides a front-side conductive paste for a crystalline silicon solar cell. The conductive paste includes, based on 100 parts by weight, metal powder 80.0-93.0 parts, organic carrier 6.0-15.0 parts, and oxide etching agent 1.0-5.0 parts. Additionally, based on 100% by mole of the oxide etching agent, the oxide etching agent includes 15-30% of PbO; 25-40% of TeO2; 8.0-15.0% of Li2O; 9.0-20.0% of SiO2; 5.0-15.0% of Bi2O3; 0.5-10.0% of ZnO, and either one or both of 0.1-10.0% of MgO and 0.1-10.0% of CaO. Optionally, the conductive paste further includes no more than 5.0% of an oxide of an additional oxide element including titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
  • In another aspect, the present disclosure provides a method for preparing a front-side conductive paste for a crystalline silicon solar cell. The method includes a step of melting raw material components of an oxide etching agent to obtain a melted oxide etching agent, a step of quenching the melt to obtain a particulate oxide etching agent, and a step of crushing to obtain a powdered oxide etching agent having a particle size ranging from 0.1 to 5.0 μm. Additionally, the method includes a step of mixing raw materials of an organic carrier in an environment of 40-100° C., to obtain the organic carrier. Furthermore, the method includes a step of mixing a metal powder with the powdered oxide etching agent and the organic carrier, to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • In yet another aspect, the present disclosure provides a method for fabricating a front-side electrode of a crystalline silicon solar cell. The method includes at least the steps of providing a crystalline silicon substrate having an insulating film overlaid on its surface, printing a front-side conductive paste for a crystalline silicon solar cell as described above on a surface of the insulating film, then drying, sintering, and cooling to obtain a front-side electrode of a crystalline silicon solar cell.
  • In addition, a crystalline silicon solar cell is provided. The crystalline silicon solar cell has a front-side electrode of a crystalline silicon solar cell as described above. The crystalline silicon solar cell includes a crystalline silicon substrate and at least one insulation film overlaid on the crystalline silicon substrate. The crystalline silicon solar cell further includes a front-side electrode in contact with the at least one insulation film and in electrical contact with the crystalline silicon substrate with a square resistance more than 90 ohms. Furthermore, the front-side electrode includes an electrically conductive metal powder, metal oxides of Pb, Te, Li, Bi, Si, Bi, and at least 0.5-10% ZnO, and either one or both of 0.1-10% MgO and 0.1-10% CaO based on 100% mole of the metal oxides.
  • Compared with the prior art, the front-side conductive paste for a crystalline silicon solar cell provided in the present invention has the following advantages. The oxide etching agent contains components of particular ratios, and these components of particular ratios exhibit excellent dissolving and etching properties. Therefore, the oxide etching agent can dissolve a sufficient amount of silver during the sintering process. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles, which allows the metal powder to form a good ohmic contact with silicon, thus greatly reducing the resistance of the front-side electrode. Finally, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is obtained.
  • The method for preparing a front-side conductive paste for a crystalline silicon solar cell provided in the present invention has simple process conditions, and the obtained front-side conductive paste has uniform components and good performance, and is suitable for mass industrial production.
  • The method for preparing a front-side electrode of a crystalline silicon solar cell provided in the present invention has the following advantages. The front-side conductive paste for a crystalline silicon solar cell provided above is employed, and the oxide etching agent can dissolve a sufficient amount of silver during the sintering process. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process after sintering, the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • Since the crystalline silicon solar cell provided in the invention employs the above-mentioned front-side electrode structure, the solar cell structure exhibits good adhesion; and the silver electrode has good ohmic contact with the silicon chip of the solar cell, so that the conversion efficiency of the solar cell is improved.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a schematic flowchart of a method for preparing a front-side conductive paste for a crystalline silicon solar cell provided in the present disclosure.
  • FIG. 2 is a schematic flowchart of a method for fabricating a front-side electrode of a crystalline silicon solar cell provided in the present disclosure.
  • FIG. 3 is a schematic diagram showing a crystalline silicon substrate having a surface provided with an insulating film, on which a front-side conductive paste according to the present disclosure is printed.
  • FIG. 4 is a schematic diagram showing the sintered crystalline silicon substrate printed with a front-side and a back-side paste shown in FIG. 3 in the present disclosure.
  • FIG. 5 is an exemplary electro microscopic image showing front-side electrode forming good contact with silicon according to an embodiment of the present disclosure.
  • FIG. 6 is a schematic diagram showing a tensile test at 180 degrees.
  • In the figures, 100-crystalline silicon substrate; 101-a first surface of the substrate; 102-a second surface of the substrate; 200-P/N junction layer; 300-insulating film; 400-printed front-side conductive paste, 401-metal powder, 402-organic carrier, 403-oxide etching agent; 500-printed back-side silver paste; 600-printed back-side aluminum paste; 700-front-side electrode; 800-solder strip; 900-tensile tester; 901-first fixing bolt for tensile sample; 902-second fixing bolt for tensile sample; F-direction of tensile force.
  • DETAILED DESCRIPTION OF THE INVENTION
  • To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention is further described in detail with reference to examples and accompanying drawings. It should be understood that the specific examples described herein are merely provided for illustrating, instead of limiting the present invention.
  • In the present invention, three parallel technical solutions are involved, which are specifically as follows:
  • A first solution is provided in the present invention. A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder of 80.0-93.0 parts, organic carrier of 6.0-15.0 parts, and oxide etching agent of 1.0-5.0 parts. Optionally, the metal powder of 80.0-83.0 parts is used. Optionally, the metal powder of 83.0-86.0 parts is used. Optionally, the metal powder of 86.0-89.0 parts is used. Optionally, the metal powder of 89.0-91.5 parts is used. Optionally, the metal powder of 91.5-93.0 parts is used. Optionally, the organic carrier of 6.0-7.0 parts is used. Optionally, the organic carrier of 7.0-8.5 parts is used. Optionally, the organic carrier of 8.5-10.0 parts is used. Optionally, the organic carrier of 10.0-11.0 parts is used. Optionally, the organic carrier of 11.0-12.0 parts is used. Optionally, the organic carrier of 12.0-13.0 parts is used. Optionally, the organic carrier of 13.0-15.0 parts is used. Optionally, the oxide etching agent of 1.0-2.0 parts is used. Optionally, the oxide etching agent of 2.0-3.0 parts is used. Optionally, the oxide etching agent of 3.0-4.0 parts is used. Optionally, the oxide etching agent of 4.0-5.0 parts is used. Optionally, based on 100% by mole of the oxide etching agent, the oxide etching agent includes at least 0.1-10% of MgO, 15-30% of PbO, 25-40% of TeO, 8-15% of Li2O, 0.1-10% of CaO, and 5-15% of Bi2O3. More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO2 25-40%; Li2O 8.0-15.0%; SiO2 9.0-20.0%; Bi2O3 5.0-15.0%; MgO 0.1-10.0%; ZnO 0.5-10.0%; CaO 0.1-10.0%; and oxide of additional elements 0-5.0%. Optionally, the oxide etching agent based on 100% by mole includes 15-17% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 17-20% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 20-24% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 24-26% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 26-28% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 28-30% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 25-30% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 30-33% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 33-36% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 36-38% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 38-40% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 8-9% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-10% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 10-11% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 11-12% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 12-13% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 13-14% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-11% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 11-13% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 13-15% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 15-16% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 16-18% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 18-20% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 5-6% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 6-8% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 8-10% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 10-12% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 12-14% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 0.1-0.2% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.2-0.4% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.4-0.6% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.6-1.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 1.0-2.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 2.0-4.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 4.0-6.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 6.0-10.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.1-0.2% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.2-0.3% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.3-0.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.7% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.7-1.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 1.0-2.2% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 2.2-3.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 3.5-5.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 5.0-6.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 6.5-7.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 7.5-9.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 9.0-10.0% of CaO.
  • In the first solution of the present invention, MgO and Li2O, CaO and Li2O, and MgO and CaO are all present at a particular molar ratio in the oxide etching agent, and specifically MgO:Li2O=0.1:15-10:8, CaO:Li2O=0.1:15-10:8, and MgO:CaO=0.1:10-10:0.1. The oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process after sintering, the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • A second solution is provided in the present invention. A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder 80.0-93.0 parts; organic carrier 6.0-15.0 parts; and oxide etching agent 1.0-5.0 parts. Optionally, the metal powder of 80.0-83.0 parts is used. Optionally, the metal powder of 83.0-86.0 parts is used. Optionally, the metal powder of 86.0-89.0 parts is used. Optionally, the metal powder of 89.0-91.5 parts is used. Optionally, the metal powder of 91.5-93.0 parts is used. Optionally, the organic carrier of 6.0-7.0 parts is used. Optionally, the organic carrier of 7.0-8.5 parts is used. Optionally, the organic carrier of 8.5-10.0 parts is used. Optionally, the organic carrier of 10.0-11.0 parts is used. Optionally, the organic carrier of 11.0-12.0 parts is used. Optionally, the organic carrier of 12.0-13.0 parts is used. Optionally, the organic carrier of 13.0-15.0 parts is used. Optionally, the oxide etching agent of 1.0-2.0 parts is used. Optionally, the oxide etching agent of 2.0-3.0 parts is used. Optionally, the oxide etching agent of 3.0-4.0 parts is used. Optionally, the oxide etching agent of 4.0-5.0 parts is used. Optionally, based on 100% by mole of the oxide etching agent, the oxide etching agent includes at least 0.1-10% of MgO, 15-30% of PbO, TeO2 25-40%, 8-15% of Li2O, and 5-15% of Bi2O3. More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO2 25-40%; Li2O 8.0-15.0%; SiO2 9.0-20.0%; Bi2O3 5.0-15.0%; MgO 0.5-10.0%; ZnO 0.5-10.0%; and oxide of additional elements 0-5.0%. Optionally, the oxide etching agent based on 100% by mole includes 15-17% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 17-20% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 20-24% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 24-26% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 26-28% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 28-30% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 25-30% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 30-33% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 33-36% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 36-38% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 38-40% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 8-9% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-10% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 10-11% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 11-12% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 12-13% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 13-14% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-11% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 11-13% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 13-15% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 15-16% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 16-18% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 18-20% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 5-6% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 6-8% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 8-10% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 10-12% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 12-14% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.6% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.6-0.7% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.7-0.9% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.9-1.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 1.0-2.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 2.0-4.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 4.0-6.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 6.0-10.0% of MgO. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO.
  • In the second solution of the present invention, MgO and Li2O, and MgO and Bi2O3 are both present at a particular molar ratio in the oxide etching agent, and specifically MgO:Li2O=0.5:15-10:8, and MgO:Bi2O3=0.5:12-10:5. The oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process after sintering, the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • A third solution is provided in the present invention. A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weight, metal powder 80.0-93.0 parts, organic carrier 6.0-15.0 parts, and oxide etching agent 1.0-5.0 parts. Optionally, the metal powder of 80.0-83.0 parts is used. Optionally, the metal powder of 83.0-86.0 parts is used. Optionally, the metal powder of 86.0-89.0 parts is used. Optionally, the metal powder of 89.0-91.5 parts is used. Optionally, the metal powder of 91.5-93.0 parts is used. Optionally, the organic carrier of 6.0-7.0 parts is used. Optionally, the organic carrier of 7.0-8.5 parts is used. Optionally, the organic carrier of 8.5-10.0 parts is used. Optionally, the organic carrier of 10.0-11.0 parts is used. Optionally, the organic carrier of 11.0-12.0 parts is used. Optionally, the organic carrier of 12.0-13.0 parts is used. Optionally, the organic carrier of 13.0-15.0 parts is used. Optionally, the oxide etching agent of 1.0-2.0 parts is used. Optionally, the oxide etching agent of 2.0-3.0 parts is used. Optionally, the oxide etching agent of 3.0-4.0 parts is used. Optionally, the oxide etching agent of 4.0-5.0 parts is used. Optionally, based on 100% by mole of the oxide etching agent, the oxide etching agent includes at least 15-30% of PbO, 25-40% of TeO, 8-15% of Li2O, 0.1-10% of CaO, and 5-15% of Bi2O3. More specifically, based on 100% by mole of the oxide etching agent, the oxide etching agent includes: PbO 15-30%; TeO2 25-40%; Li2O 8.0-15.0%; SiO2 9.0-20.0%; Bi2O3 5.0-15.0%; ZnO 0.5-10.0%; CaO 0.1-10.0%; and oxide of additional elements 0-5.0%. Optionally, the oxide etching agent based on 100% by mole includes 15-17% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 17-20% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 20-24% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 24-26% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 26-28% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 28-30% of PbO. Optionally, the oxide etching agent based on 100% by mole includes 25-30% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 30-33% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 33-36% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 36-38% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 38-40% of TeO2. Optionally, the oxide etching agent based on 100% by mole includes 8-9% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-10% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 10-11% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 11-12% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 12-13% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 13-14% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Li2O. Optionally, the oxide etching agent based on 100% by mole includes 9-11% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 11-13% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 13-15% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 15-16% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 16-18% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 18-20% of SiO2. Optionally, the oxide etching agent based on 100% by mole includes 5-6% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 6-8% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 8-10% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 10-12% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 12-14% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 14-15% of Bi2O3. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.6-0.8% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.8-1.1% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 1.1-2.2% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 2.2-3.3% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 3.3-5.0% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 5.0-6.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 6.5-7.5% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 7.5-8.6% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 8.6-10.0% of ZnO. Optionally, the oxide etching agent based on 100% by mole includes 0.1-0.2% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.2-0.3% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.3-0.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.5-0.7% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 0.7-1.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 1.0-2.2% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 2.2-3.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 3.5-5.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 5.0-6.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 6.5-7.5% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 7.5-9.0% of CaO. Optionally, the oxide etching agent based on 100% by mole includes 9.0-10.0% of CaO.
  • In the third solution of the present invention, CaO and Li2O, and CaO and Bi2O3 are both present at a particular molar ratio in the oxide etching agent, and specifically CaO:Li2O=0.5:15-10:8, and CaO:Bi2O3=0.5:15-10:5. The oxide etching agent is melted to form a liquid during the sintering process, so that a sufficient amount of silver is dissolved therein. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powder. The other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process after sintering, the liquid oxide etching agent is deposited on the silicon substrate as a high resistivity solid layer, the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles which is distributed in the high resistivity solid layer of the oxide etching agent, which allows the metal powder to form a good ohmic contact with the silicon, thus reducing the resistance. In this way, a front-side electrode with low contact resistance, good electrical conductivity and strong adhesion is formed.
  • In the three parallel technical solutions, the additional element in the oxide of the additional element is one or two or more of titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
  • The oxide etching agent in the three solutions of the present invention includes not only an oxide prepared by a chemical method and an oxide obtained by a high-temperature treatment, but also a carbonate, a phosphate, and a fluoride containing a cation, etc. For example, the lithium oxide Li2O may be replaced by Li2CO3.
  • Preferably, in the three parallel solutions, the oxide etching agent may be crystalline, amorphous, or a mixture of amorphous and crystalline.
  • In the three parallel solutions, the same metal powder and organic carrier may be used.
  • Optionally, the metal powder is particles of at least one metal element of silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium.
  • Optionally, the metal powder is silver-coated particles. Each particle is at least one metal element of copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese, coated by a silver layer of a thickness in a range of 10-50 nm.
  • Optionally, the metal powder is a mixture of a non-silver-coated metal powder and a silver-coated metal powder, where a weight ratio of the non-silver coated metal powder to the silver-coated metal powder is 5/95-95/5. The non-silver-coated metal powder includes at least one metal element of silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium, the silver-coated metal powder includes at least one metal element of copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese. Particles of the silver-coated metal powder includes a silver coating with a thickness in a range of 10-200 nm.
  • The organic carrier mentioned in the present invention includes an organic solvent, a polymer, a wetting dispersant, a thixotropic agent, and an additional functional additive.
  • Based on 100 parts by weight of the organic carrier, the organic carrier includes 50-95 parts of the organic solvent; 1-40 parts of the polymer; 0.1-10 parts of the wetting dispersant; and 1-20 parts of the thixotropic agent. Optionally, based on 100 parts by weight, 50-55 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 55-60 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 60-71 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 71-77 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 77-82 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 82-85 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 85-88 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 88-90 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 90-92 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 92-94 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 94-95 parts of the organic solvent is used. Optionally, based on 100 parts by weight, 1-2 parts of the polymer is used. Optionally, based on 100 parts by weight, 2-3 parts of the polymer is used. Optionally, based on 100 parts by weight, 3-5 parts of the polymer is used. Optionally, based on 100 parts by weight, 5-8 parts of the polymer is used. Optionally, based on 100 parts by weight, 8-12 parts of the polymer is used. Optionally, based on 100 parts by weight, 12-18 parts of the polymer is used. Optionally, based on 100 parts by weight, 18-25 parts of the polymer is used. Optionally, based on 100 parts by weight, 25-34 parts of the polymer is used. Optionally, based on 100 parts by weight, 34-37 parts of the polymer is used. Optionally, based on 100 parts by weight, 37-40 parts of the polymer is used. Optionally, based on 100 parts by weight, 0.1-0.2 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 0.2-0.3 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 0.3-0.4 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 0.4-0.6 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 0.6-0.9 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 0.9-1.2 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 1.2-2.2 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 2.2-4.2 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 4.2-5.5 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 5.5-6.5 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 6.5-7.8 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 7.8-9.0 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 9.0-1.0 parts of the wetting dispersant is used. Optionally, based on 100 parts by weight, 1-2 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 2-3 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 3-4 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 4-6 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 6-9 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 9-12 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 12-15 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 15-17 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 17-18 parts of the thixotropic agent is used. Optionally, based on 100 parts by weight, 18-20 parts of the thixotropic agent is used.
  • The organic solvent is at least one selected from terpineol, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, a dodecanol ester, diethylene glycol butyl ether, triethylene glycol butyl ether, tripropylene glycol methyl ether, a terpene, and other high-boiling point solvents.
  • The polymer is at least one selected from ethyl cellulose, methyl cellulose, cellulose and a derivative thereof, an acrylic resin, an alkyd resin, and a polyester resin.
  • The wetting dispersant is one or two or more selected from a fatty acid (e.g. oleic acid and stearic acid), an amide derivative of a fatty acid (e.g. oleamide, and stearamide), an ester derivative of a fatty acid, polyethylene wax, and polyethylene glycol, which mainly functions to disperse the inorganic powder in the organic carrier.
  • The thixotropic agent is one or two or more selected from a hydrogenated castor oil derivative, polyamide wax, polyurea, and fumed silica, and mainly functions to increase the thixotropy of the paste during the printing process, so that the consistency of the silver paste becomes smaller when sheared during the printing process, and it is easy to perform screen printing; and when the shearing is stopped, the consistency is increased to ensure that the electrode has an excellent aspect ratio.
  • Further, the organic carrier may also include a functional additive in an amount of 0.1-20 parts by weight. Based on 100 parts by weight of the organic carrier, the functional additive optionally includes 0.1-0.2 parts. Optionally, the functional additive includes 0.2-0.3 parts. Optionally, the functional additive includes 0.3-0.5 parts. Optionally, the functional additive includes 0.5-0.7 parts. Optionally, the functional additive includes 0.7-1.0 parts. Optionally, the functional additive includes 1.0-2.0 parts. Optionally, the functional additive includes 2.0-5.0 parts. Optionally, the functional additive includes 5.0-10.0 parts. Optionally, the functional additive includes 10.0-15.0 parts. Optionally, the functional additive includes 15.0-20.0 parts. Optionally, the functional additive is one or two or more chemical species selected from poly (methylphenyl) siloxane, polyphenylsiloxane, a phthalate (e.g. diethyl phthalate, and dibutyl phthalate), micro-crystalline wax, polydimethylsiloxane, polyvinylbutyral (PVB), a polyether- and polyester-modified organosiloxane, and an alkyl-modified organosiloxane. The additional functional additive may be optionally added, for example, micro-crystalline wax is added to reduce the surface tension, dibutyl phthalate (DBP) is added to improve the flexibility of the paste, and polyvinylbutyral (PVB) is added to improve the adhesion.
  • As shown in FIG. 1, a method for preparing a front-side conductive paste for a crystalline silicon solar cell according to the present invention includes the following steps:
  • S01. Preparation of oxide etching agent: Raw materials of the oxide etching agent are weighed according to the raw material proportion in any one of the above three solutions and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a oven and heated to 900-1100° C. for 60-180 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is quenched, to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried at a temperature of 60-80° C.; and the dried particulate oxide etching agent is crushed to obtain a powdered oxide etching agent having a particle size of 0.5-5.0 μm, which is then dried in a drying oven at 80-100° C. to obtain a dried powdered oxide etching agent.
  • Optionally, the quenching method includes cooling the melted liquid oxide etching agent by pouring it into water at 5-25° C. or cooling in flowing cold air at room temperature, where the temperature of the flowing cold air is at 25° C. or below.
  • The above-mentioned crushing of the particulate oxide etching agent may be performed by ball milling in a ball miller, or by other methods to make the particle size of the oxide etching agent smaller.
  • S02. Preparation of organic carrier: Raw materials of the organic carrier are sequentially weighed according to the weight proportion of the raw materials of the organic carrier as described above, and the weighed raw materials of the organic carrier are placed in a container, and mixed by stirring at a temperature of 40-100° C. for 100-160 min to obtain an organic carrier.
  • S03. Preparation of front-side conductive paste: The metal powder is mixed with the above prepared oxide etching agent and organic carrier, and ground to obtain front-side conductive silver paste.
  • An alternative method for preparing a front-side conductive paste for a crystalline silicon solar cell according to the present invention is also provided.
  • In an embodiment, the oxide etching agent and the metal powder are first mixed to obtain a first mixture, and then the first mixture is mixed with the organic carrier, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • In another embodiment, the oxide etching agent and the organic carrier are first mixed to obtain a first mixture, and then the metal powder is added to the first mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • In still another embodiment, the metal powder and organic carrier are first mixed to obtain a first mixture, and then the oxide etching agent is added to the first mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • In a further embodiment, the amounts of the metal powder, organic carrier, and oxide etching agent are respectively taken as 100 parts by weight; and 20-60 parts by weight of the metal powder and 20-60 parts by weight of the organic carrier are first mixed to obtain a first mixture, then 40-80 parts by weight of the oxide etching agent is mixed with a part of the organic carrier to obtain a second mixture, and then the first mixture is mixed with the second mixture, and ground to obtain the front-side conductive paste for a crystalline silicon solar cell.
  • Referring to FIG. 2, FIG. 3 and FIG. 4, the present invention further provides a method for fabricating a front-side electrode of a crystalline silicon solar cell.
  • In the fabrication method, a crystalline silicon substrate has a surface having an insulating film deposited, as shown in FIG. 3. Referring to FIG. 3, a crystalline silicon chip 100 having a first surface 101 and a second surface 102 opposing to each other. On the first surface 101, a P/N junction layer 200 and an insulating film 300 are sequentially and outwardly laminated. On the second surface 102, a back-side silver paste 500 and a back-side aluminum paste 600 are printed. Optionally, the insulating film 300 may be deposited with at least one of a silicon nitride film, a titanium oxide film, an aluminum oxide film, and a silicon oxide film.
  • Specifically, the method for fabricating a front-side electrode of a crystalline silicon solar cell includes at least the following steps:
  • Step S04: A crystalline silicon substrate having an insulating film 300 deposited on its surface is provided.
  • Step S05: A front-side conductive paste 400 for a crystalline silicon solar cell (where 401 is a metal powder, 402 is an organic carrier, and 403 is an oxide etching agent) according to any one of the above solutions is printed on a surface of the insulating film 300.
  • Step S06: The crystalline silicon substrate treated in the step S05 is sequentially dried, sintered, and cooled to obtain a front-side electrode 700 of a crystalline silicon solar cell.
  • Specifically, the drying temperature is 80-400° C., the sintering temperature is 700-820° C., and the cooling is natural cooling (in flowing air at room temperature).
  • The present invention further provides a crystalline silicon solar cell employing a front-side electrode of a crystalline silicon solar cell as described above.
  • In order to better illustrate the front-side conductive paste for a crystalline silicon solar cell and the preparation method therefor provided in the embodiments of the present invention, the present invention is further described by way of examples hereinafter.
  • EXAMPLE 1
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.0 parts of a silver powder; 9.0 parts of an organic carrier; and 3.0 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes: 22% of PbO, 30% of TeO2, 9.0% of Li2O, 18.0% of SiO2, 10.0% of Bi2O3, 10% of MgO, 0.5% of ZnO, and 0.5% of CaO.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.0 parts of the silver powder, 9.0 parts of the organic carrier and 3.0 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste for a crystalline silicon solar cell obtained in Example 1 is printed by screen printing on a front side of a silicon substrate of a crystalline silicon solar cell having an insulating film, where a back side of the substrate is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the silicon solar cell is sintered at 770° C. to form a front-side electrode of the crystalline silicon solar cell as shown in FIG. 5. During the sintering, the organic carrier in the front-side conductive paste is evaporated, the oxide etching agent in the front-side conductive paste is melted to form a liquid to contact with the silver powders, so that a sufficient amount of silver is dissolved therein. One portion of the liquid oxide etching agent in which the silver is dissolved is used to wet the metal powder and facilitate the sintering of the metal powders. The other portion of the liquid oxide etching agent in which the silver is dissolved flows to the surface of the solar cell and reacts with the anti-reflective layer, so that the anti-reflective layer is effectively etched. During the cooling process after sintering, the liquid oxide etching agent is deposited on the silicon substrate A02 as a high-resistivity solid layer (an insulation film), the silver dissolved in the liquid oxide etching agent is precipitated out to form fine silver nanoparticles A03 which are distributed in the high-resistivity solid layer of the oxide etching agent, which allow a good ohmic contact to form between metal in the paste with the silicon substrate A02, thus reducing the resistance and enhancing current flow for the silicon solar cell. In this way, a front-side electrode A01 with low contact resistance, good electrical conductivity, and strong adhesion is formed for the silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 2
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes: 30% of PbO, 25% of TeO2, 15% of Li2O, 9.0% of SiO2, 5.0% of Bi2O3, 4.0% of MgO, 2.0% of ZnO, and 10% of CaO.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps:
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 2 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 3
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 25% of PbO, 20.5% of TeO2, 13% of Li2O, 9.5% of SiO2, 12% of Bi2O3, 3.0% of MgO, 10% of ZnO, and 7.0% of CaO.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 3 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 780° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 4
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 22.9% of PbO, 25% of TeO2, 14% of Li2O, 15% of SiO2, 14% of Bi2O3, 8.0% of MgO, 0.5% of ZnO, 0.1% of CaO, and 0.5% of Al2O3.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 4 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 780° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 5
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 25% of PbO, 30% of TeO2, 8.0% of Li2O, 10% of SiO2, 10.0% of Bi2O3, 6.0% of MgO, 5.5% of ZnO, 5.0% of CaO, and 0.5% of TiO2.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste for a crystalline silicon solar cell obtained in Example 5 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 790° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 6
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 24% of PbO, 25% of TeO2, 9% of Li2O, 15% of SiO2, 15% of Bi2O3, 0.1% of MgO, 0.9% of ZnO, 10% of CaO, 0.5% of Al2O3, and 0.5% of TiO2.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 6 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 7
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 20% of PbO, 25% of TeO2, 15% of Li2O, 20% of SiO2, 9% of Bi2O3, 0.5% of ZnO, 10% of CaO, and 0.5% of TiO2.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 7 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 8
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 21% of PbO, 25% of TeO2, 14% of Li2O, 10.5% of SiO2, 11% of Bi2O3, 8.0% of MgO, 10% of ZnO, and 0.5% of Al2O3.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 8 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 9
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 25% of PbO, 26% of TeO2, 7% of Li2O, 19.5% of SiO2, 15% of Bi2O3, 0.3% of MgO, 7% of ZnO, and 0.2% of CaO.
  • The oxide etching agent is prepared as follows: Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 9 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 10
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 25% of PbO, 25% of TeO2, 6.0% of Li2O, 15% of SiO2, 15% of Bi2O3, 2.0% of MgO, 5.0% of ZnO, 5.0% of CaO, 1.5% of Al2O3, and 0.5% of TiO2.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 10 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 11
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 33% of PbO, 22% of TeO2, 4% of Li2O, 18% of SiO2, 14% of Bi2O3, 5% of MgO, 3% of ZnO, and 1% of CaO.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 11 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 12
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 13.3% of PbO, 39% of TeO2, 5% of Li2O, 6.6% of SiO2, 20% of Bi2O3, 13% of MgO, 3% of ZnO, and 0.1% of CaO.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 12 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 770° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 13
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 18.8% of PbO, 22% of TeO2, 4% of Li2O, 16% of SiO2, 20% of Bi2O3, 16% of MgO, 3% of ZnO, and 0.2% of CaO.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 13 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell.
  • The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 14
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 17.3% of PbO, 22% of TeO2, 4% of Li2O, 18.7% of SiO2, 4% of Bi2O3, 16% of MgO, 3% of ZnO, and 15% of CaO.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 μm, which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 14 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • EXAMPLE 15
  • A front-side conductive paste for a crystalline silicon solar cell includes, based on 100 parts by weights, 88.5 parts of a silver powder; 9.0 parts of an organic carrier; and 2.5 parts of an oxide etching agent.
  • Based on 100% by mole of the oxide etching agent, the oxide etching agent includes 18.8% of PbO, 22% of TeO2, 7% of Li2O, 12% of SiO2, 20% of Bi2O3, 0.2% of MgO, 3% of ZnO, and 17% of CaO.
  • The oxide etching agent is prepared as follows. Raw materials of the oxide etching agent are weighed according to the above proportion and uniformly mixed; the uniformly mixed raw materials of the oxide etching agent are placed in a heater and heated to 1000° C. for 120 min, to obtain a melted liquid oxide etching agent; the melted liquid oxide etching agent is cooled by pouring into water at normal temperature (25° C.), to obtain a particulate oxide etching agent; the particulate oxide etching agent is dried in a drying oven at a temperature of 80° C.; and the dried particulate oxide etching agent is milled in a ball mill to obtain a powdered oxide etching agent having a particle size of 0.5-7.0 which is then dried in a drying oven at 100° C. to obtain a dried powdered oxide etching agent.
  • Based on 100% by weight of the organic carrier, the organic carrier includes 70% of a mixture of terpineol, a dodecanol ester, and a terpene; 10% of ethyl cellulose, 15% of rosin resin, and 5% of polyamide wax.
  • A method for preparing the front-side conductive paste for a crystalline silicon solar cell includes the following steps.
  • 88.5 parts of the silver powder, 9.0 parts of the organic carrier and 2.5 parts of the oxide etching agent powder are weighed according to the above weight proportions, uniformly mixed and ground to obtain a front-side conductive paste for a crystalline silicon solar cell.
  • A method for fabricating a front-side electrode of a crystalline silicon solar cell includes the following steps.
  • The front-side conductive paste obtained in Example 15 is printed by screen printing on a front side of a crystalline silicon solar cell having an insulating film, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered at 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. The efficiency of the obtained silicon solar cell chip is tested, and the I-V test results are summarized in Table 1.
  • COMPARATIVE EXAMPLE
  • The front-side conductive paste PVM1B for a crystalline silicon solar cell widely available from the market is printed by screen printing on a front side of a crystalline silicon solar cell having the same insulating film as that in the examples, where a back side of the solar cell is screen printed with a back-side silver paste and a back-side aluminum paste. Then, the solar cell is sintered by heating to 800° C. to obtain a front-side electrode of the crystalline silicon solar cell. Then the efficiency of the silicon solar cell chip is tested, and the IV test results are summarized in Table 1.
  • Performance Tests
  • (1) I-V Test
  • The silicon solar cell chips of Examples 1-15 and the solar cell chip of Comparative Example are subjected to an I-V test on a HALM IV tester, and the results are shown in Table 1.
  • (2) Tensile Test
  • A solder strip is soldered to a main grid and then a tensile test at 180 degrees is performed. The main grid is 0.7 mm wide, and a 0.9 mm-wide solder strip is soldered to the main grid. The solder strip is 0.9 mm wide, 0.23 mm thick and has a composition of 96.5% Sn and 3.5% Ag. FIG. 6 is a schematic diagram showing a tensile test at 180 degrees. Specifically, a solder strip 800 is first soldered to the surface of a main grid, and then the crystalline silicon cell chip 100 is fixed to a tensile tester 900 by using a first fixing bolt 901 and a second fixing bolt 902. The tensile test is performed in the direction of the tensile force F. The tensile test results are shown in Table 1.
  • TABLE 1
    Statistics of performance test data of crystalline silicon solar
    cells obtained in Examples 1-15 and in Comparative Example
    Tensile
    Scheme Number Uoc Isc FF Eta Rs Rsh IRev1 force (N)
    Example 1 16pcs 0.6292 8.9481 79.04 18.29 0.00177 100 0.29 4.3
    Example 2 16pcs 0.6288 8.9922 78.66 18.28 0.00190 95 0.35 4.4
    Example 3 16pcs 0.6287 8.9246 79.24 18.27 0.00175 84 0.48 3.9
    Example 4 16pcs 0.6278 8.9229 78.66 18.41 0.00186 39 0.65 4.4
    Example 5 16pcs 0.6320 9.0354 80.00 18.77 0.00151 211 0.14 5.0
    Example 6 16pcs 0.6317 9.0269 80.05 18.76 0.00140 100 0.33 2.8
    Example 7 16pcs 0.6295 9.0143 79.43 18.52 0.00142 84 0.29 4.3
    Example 8 16pcs 0.6292 8.9674 79.22 18.37 0.00151 93 0.31 4.3
    Example 9 16pcs 0.6301 8.8905 66.33 15.69 0.05336 223 0.23 5.6
    Example 10 16pcs 0.6101 8.8288 76.09 16.85 0.03060 456 0.16 5.4
    Example 11 16pcs 0.6302 8.8252 75.99 17.60 0.01959 104 0.24 5.5
    Example 12 16pcs 0.6305 8.8167 75.93 17.59 0.01953 80 0.38 5.5
    Example 13 16pcs 0.6301 8.8357 76.00 17.57 0.02025 174 0.18 2.9
    Example 14 16pcs 0.6296 8.8294 76.33 17.63 0.01994 265 0.13 4.1
    Example 15 16pcs 0.6283 8.8712 76.12 17.75 0.02050 194 0.21 4.9
    Comparative 16pcs 0.6294 8.8866 76.92 18.12 0.02847 318 0.13 2.9
    Example
  • As can be seen from Table 1, the conversion efficiency of the solar cells of Examples 1-8 is on average 18.46%, which is quite significant over the rate 18.12% achieved by the solar cell of Comparative Example. The conversion rate of Examples 9-15 is lower than that of the solar cell of Comparative Example. In Examples 1-15, the difference in conversion rate of the solar cells is mainly caused by the different oxide etching agents used, because the same silver powder and organic carrier are used in these examples. Alternatively, the series resistance (Rs) of the solar cells of Example 1-8 is (<0.002 Ohms) significantly lower than 0.028 Ohms of the solar cells of Comparative Example. This indicates that the electrical contact formed between the metal element and the silicon substrate or cell chip of the solar cell by applying the conductive paste based on Examples 1-8 over the insulation film on the silicon solar cell chip is significantly improved over the electrical contact by using conventional conductive paste.
  • The oxide etching agents of Examples 1-6 have better performance due to their unique proportions of oxide components, and the molar contents of the oxide are in the following ranges: PbO 15-30%, TeO2 25-40%, Li2O 8-15%, SiO2 9-20%, Bi2O3 5-15%, MgO 0.1-8%, ZnO 0.5-10.0%, CaO 0.1-10.0%, and oxides of additional elements Al2O3 and TiO2 0-5.0%. The unique proportions of the oxide components allow the oxide etching agent to dissolve sufficient silver during the sintering process, which can fully etch the insulating layer on the surface of the cell chip without excessively etching the silicon cell chip, so that the silver electrode has not only good ohmic contact with, but also high adhesion to the silicon cell chip.
  • The oxide etching agent of Example 7 contains no MgO, but a amount of CaO, and also has good performance. The oxide etching agent of Example 8 contains no CaO, but a amount of MgO, and also has good performance.
  • The conversion rate of the solar cells of Examples 9-15 is lower than that of Comparative Example. The series resistance (Rs) of the solar cells of Example 9-15 is significantly higher because the molar proportions of the oxides used in the oxide etching agent is not in the optimum range. The oxide etching agent cannot effectively erode the insulating film on the silicon solar cell chip during the sintering process, and the front side silver electrode does not form a good contact with the silicon substrate.
  • Based on the present disclosure of the front-side conductive paste suggested in Examples 1-8, in yet another aspect, a crystalline silicon solar cell is provided. The crystalline silicon solar cell includes a crystalline silicon substrate and at least one insulation film deposited on the crystalline silicon substrate. The crystalline silicon solar cell further includes a front-side electrode in contact with the at least one insulation film and in electrical contact with the crystalline silicon substrate characterized by a series resistance no greater than 0.002 Ohms. Furthermore, the front-side electrode includes an electrically conductive metal powder, oxides of several metal elements including Pb, Te, Li, Bi, Si, Bi, at least 0.5-10 wt % ZnO, and either one or both of 0.1-10 wt % MgO and 0.1-10 wt % CaO.
  • The present invention has been described in detail with reference to preferred embodiments, which however are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements can be made without departing from the spirit and principle of the present invention, which are all fall within the protection scope of the present invention.

Claims (15)

What is claimed is:
1. A crystalline silicon solar cell comprising:
a crystalline silicon substrate;
at least one insulation film overlaid on the crystalline silicon substrate; and
a front-side electrode in contact with the at least one insulation film and in electrical contact with the crystalline silicon substrate characterized by a series resistance no greater than 0.002 Ohms, the front-side electrode comprising an electrically conductive metal powder, metal oxides of Pb, Te, Li, Si, Bi, and at least 0.5-10% ZnO, and either one or both of 0.1-10% MgO and 0.1-10% CaO based on 100% mole of the metal oxides.
2. The crystalline silicon solar cell of claim 1, wherein the front-side electrode comprises a conductive paste printed overlying the insulation film, the conductive paste comprising, based on 100 parts by weight,
80.0-93.0 parts of a metal powder;
6.0-15.0 parts of an organic carrier;
1.0-5.0 parts of an oxide etching agent wherein based on 100% by mole, the oxide etching agent comprises 15-30% of PbO; 25-40% of TeO2; 8.0-15.0% of Li2O; 9.0-20.0% of SiO2; 5.0-15.0% of Bi2O3; 0.5-10.0% of ZnO; and either one or both of 0.1-10.0% of MgO and 0.1-10.0% of CaO.
3. The crystalline silicon solar cell of claim 2, wherein the conductive paste further comprises no more than 5% of an oxide of one or more elements selected from titanium, aluminum, silver, chromium, scandium, copper, niobium, vanadium, sodium, tantalum, strontium, bromine, cobalt, hafnium, lanthanum, yttrium, ytterbium, iron, barium, manganese, tungsten, nickel, tin, arsenic, zirconium, potassium, phosphorus, indium, gallium, and germanium.
4. The crystalline silicon solar cell of claim 2, wherein the oxide etching agent comprises particles in at least one state of crystalline and amorphous.
5. The crystalline silicon solar cell of claim 2, wherein the metal powder comprises particles of at least one element selected from silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium.
6. The crystalline silicon solar cell of claim 2, wherein the metal powder comprises particles of at least one element selected from copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese, wherein each of the particles is coated by a silver layer having a thickness of 10-50 nm.
7. The crystalline silicon solar cell of claim 2, wherein the metal powder comprises a mixture of non-silver-coated particles and silver-coated particles with a weight ratio in a range from 5/95 to 95/5, wherein the non-silver-coated particles comprise at least one element selected from silver, gold, platinum, copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, manganese, palladium, and rhodium, and the silver-coated particles comprise at least one element selected from copper, iron, nickel, zinc, titanium, cobalt, chromium, aluminum, and manganese, each of the silver-coated particles is coated by a silver layer having a thickness of 10 -200 nm.
8. The crystalline silicon solar cell of claim 2, wherein the organic carrier comprises, based on 100 parts, 50-95 parts of an organic solvent, 1-40 parts of a polymer, 0.1-10 parts of a wetting dispersant, 1-20 parts of a thixotropic agent, and 0.1-20 parts of a functional additive.
9. The crystalline silicon solar cell of claim 8, wherein the organic solvent is at least one of terpineol, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, a dodecanol ester, diethylene glycol butyl ether, triethylene glycol butyl ether, tripropylene glycol methyl ether, and a terpene.
10. The crystalline silicon solar cell of claim 8, wherein the polymer is at least one selected from ethyl cellulose, methyl cellulose, cellulose and a derivative thereof, an acrylic resin, an alkyd resin, and a polyester resin.
11. The crystalline silicon solar cell of claim 8, wherein the wetting dispersant is one or a mixture of one or two or more selected from a fatty acid, an amide derivative of a fatty acid, an ester derivative of a fatty acid, polyethylene wax, and polyethylene glycol.
12. The crystalline silicon solar cell of claim 8, wherein the thixotropic agent is at least one selected from a hydrogenated castor oil derivative, polyamide wax, polyurea, and fumed silica.
13. The crystalline silicon solar cell of claim 8, wherein the functional additive is one or two or more selected from poly (methylphenyl) siloxane, polyphenylsiloxane, a phthalate, diethyl phthalate, dibutyl phthalate, micro-crystalline wax, polydimethylsiloxane, polyvinylbutyral, a polyether- and polyester-modified organosiloxane, and an alkyl-modified organosiloxane.
14. The crystalline silicon solar cell of claim 2, wherein the conductive paste is dried at a temperature within 80-400° C., sintered at a temperature within 700-820° C., and cooled naturally in flowing air at room temperature.
15. The crystalline silicon solar cell of claim 1, wherein the insulating film comprises one of a silicon nitride film, a titanium oxide film, an aluminum oxide film, and a silicon oxide film.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114446510A (en) * 2022-02-23 2022-05-06 东莞市山盟科技有限公司 Environment-friendly compound modified conductive silver paste and preparation method thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111499208B (en) * 2020-04-23 2021-08-06 常州聚和新材料股份有限公司 Glass material for front silver paste of monocrystalline silicon solar cell and preparation method and application thereof
CN112489851B (en) * 2020-11-09 2022-01-07 广州市儒兴科技开发有限公司 N-type efficient battery front silver-aluminum paste
CN114724742A (en) * 2021-12-22 2022-07-08 西安创联光电新材料有限公司 Back silver paste for crystalline silicon solar cell and preparation method and application thereof
CN114038608B (en) * 2021-12-24 2022-04-19 西安宏星电子浆料科技股份有限公司 Low-resistivity solar cell conductive paste
CN114213018B (en) * 2021-12-29 2022-08-16 江苏日御光伏新材料科技有限公司 Ceramic glass powder and solar cell metallization slurry containing same
CN114180844B (en) * 2021-12-29 2022-09-13 江苏日御光伏新材料科技有限公司 Lithium-tellurium-silicon binary glass oxide composite system and conductive paste containing same
CN114409248B (en) * 2022-01-06 2023-04-07 江苏日御光伏新材料科技有限公司 Low-heat-loss tellurium-lithium-silicon-zirconium system glass material, and conductive paste and application thereof
CN114530280A (en) * 2022-04-21 2022-05-24 西安宏星电子浆料科技股份有限公司 Low-cost thick-film conductor paste
CN117727488A (en) * 2024-02-18 2024-03-19 浙江晶科新材料有限公司 Conductive paste for N-type TOPCON solar cell, preparation method and solar cell

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5281561A (en) * 1993-02-09 1994-01-25 Dumesnil Maurice E Low temperature sealing glass composition
CN101609849B (en) * 2009-07-13 2010-11-03 中南大学 Silver conductive paste used for positive electrode of solar battery and preparation technique thereof
KR101569566B1 (en) 2010-05-04 2015-11-16 이 아이 듀폰 디 네모아 앤드 캄파니 Thick-film pastes containing lead-tellurium-lithium-titanium-oxides, and their use in the manufacture of semiconductor devices
CN102280161B (en) * 2011-08-18 2013-08-28 陈晓东 Conductive paste for positive electrode of crystal silicon solar cell and preparation method of conductive paste
CN102354544B (en) * 2011-09-21 2013-03-06 江苏泓源光电科技有限公司 Silver conductive paste for front electrode of crystalline silicon solar cell and preparation method thereof
WO2013109583A2 (en) * 2012-01-16 2013-07-25 Ferro Corporation Non fire-through aluminum conductor reflector paste for back surface passivated cells with laser fired contacts
KR101999795B1 (en) * 2012-06-27 2019-07-12 삼성전자주식회사 Conductive paste and electronic device and solar cell including an electrode formed using the conductive paste
CN102881350B (en) * 2012-09-25 2015-07-22 深圳市首骋新材料科技有限公司 Positive electrode slurry of solar battery and glass powder
KR101587683B1 (en) * 2013-02-15 2016-01-21 제일모직주식회사 The composition for forming solar cell electrode comprising the same, and electrode prepared using the same
CN103545016B (en) * 2013-10-21 2016-06-29 深圳市首骋新材料科技有限公司 Crystal silicon solar energy battery front electrode electrocondution slurry and preparation method thereof
US9761348B2 (en) * 2014-03-10 2017-09-12 E I Du Pont De Nemours And Company Conductive paste used for solar cell electrodes
CN105097067B (en) * 2014-05-15 2017-11-14 三星Sdi株式会社 For forming the composition of solar cel electrode and the electrode using its preparation
EP3367391B1 (en) * 2016-12-30 2023-06-28 DK Electronic Materials, Inc Paste composition used for preparing solar cell electrode, solar cell electrode, and solar cell
CN112041994B (en) * 2018-03-30 2022-06-21 深圳市首骋新材料科技有限公司 Crystalline silicon solar cell front conductive paste and preparation method thereof and solar cell

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114446510A (en) * 2022-02-23 2022-05-06 东莞市山盟科技有限公司 Environment-friendly compound modified conductive silver paste and preparation method thereof

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