WO2020111900A1 - Conductive paste for solar cell electrode, and solar cell manufactured using same - Google Patents

Conductive paste for solar cell electrode, and solar cell manufactured using same Download PDF

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Publication number
WO2020111900A1
WO2020111900A1 PCT/KR2019/016804 KR2019016804W WO2020111900A1 WO 2020111900 A1 WO2020111900 A1 WO 2020111900A1 KR 2019016804 W KR2019016804 W KR 2019016804W WO 2020111900 A1 WO2020111900 A1 WO 2020111900A1
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WIPO (PCT)
Prior art keywords
solar cell
glass frit
conductive paste
coated
electrode
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PCT/KR2019/016804
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French (fr)
Korean (ko)
Inventor
노화영
김인철
고민수
장문석
김충호
박강주
전태현
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엘에스니꼬동제련 주식회사
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Publication of WO2020111900A1 publication Critical patent/WO2020111900A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
    • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02167—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor 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
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor 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
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a conductive paste used for forming an electrode of a solar cell and a solar cell manufactured using the conductive paste.
  • a solar cell is a semiconductor device that converts solar energy into electrical energy, and generally has a p-n junction type, and its basic structure is the same as that of a diode.
  • the solar cell device is generally constructed using a p-type silicon semiconductor substrate having a thickness of 180 to 250 ⁇ m.
  • an n-type impurity layer having a thickness of 0.3 to 0.6 ⁇ m, an antireflection film and a front electrode are formed thereon.
  • a back electrode is formed on the back side of the p-type silicon semiconductor substrate.
  • the front electrode is coated with a conductive paste containing silver-based conductive powder (silver powder), glass frit, organic vehicle, and additives on an anti-reflection film, followed by firing to form an electrode.
  • the back electrode is formed by applying an aluminum paste composition composed of aluminum powder, glass frit, organic vehicle and additives by screen printing and drying, followed by baking at a temperature of 660° C. (melting point of aluminum) or higher.
  • aluminum diffuses into the p-type silicon semiconductor substrate, whereby an Al-Si alloy layer is formed between the back electrode and the p-type silicon semiconductor substrate, and at the same time, a p+ layer is formed as an impurity layer by diffusion of aluminum atoms. do.
  • the presence of the p+ layer prevents recombination of electrons and obtains a back surface field (BSF) effect that improves the collection efficiency of the resulting carrier.
  • a rear silver electrode may be further positioned under the rear aluminum electrode.
  • the glass frit etched the anti-reflection layer (SiNx) coated on the surface of the silicon wafer (Si-wafer) so that the n-layer of the wafer and Ag of the front electrode form an ohmic contact, thereby making the solar cell It is essential for Ag/Si contact of silicon solar cells because it serves to secure reliability by forming circuits, increasing efficiency, and increasing adhesion.
  • the etching of the antireflection film was controlled by adjusting the component system, particle size, or content of the glass frit, but many problems were caused in the dispersion of the glass frit.
  • the thickness of the glass layer is not uniform, so that the n layer is damaged in the thick region, and the penetration of silver powder decreases in the thin region, resulting in a decrease in current or an increase in resistance.
  • Patent Document 1 U.S. Patent Registration 8,748,327 B1 (2014.06.10.)
  • Patent Document 2 WO Publication Patent 2013/105812 A1 (2013.07.18.)
  • Patent Document 3 US Patent Publication 2011-0094578 A1 (2011.04.28.)
  • the present invention aims to improve the power generation efficiency of a solar cell by improving the electrical properties of the solar cell electrode formed by coating the surface of the glass frit in the composition of the conductive paste for solar cell electrodes to improve dispersibility. .
  • the present invention provides a conductive paste for a solar cell electrode comprising a metal powder, a glass frit, and an organic vehicle, wherein the surface of the glass frit is coated with fatty amine and fatty acid.
  • the glass frit is characterized in that the primary coating with the fatty amine or fatty acid, the secondary coating with the fatty amine or fatty acid.
  • the glass frit is characterized by using a glass frit primary coated with fatty amine and secondary coated with fatty amine or fatty acid.
  • the glass frit is characterized by using a glass frit primary coated with fatty amines and secondary coated with fatty acids.
  • the fatty amine is characterized in that it comprises an alkylamine-based material having 6 to 24 carbon atoms.
  • alkylamine-based material is triethylamine, heptylamine, octadecylamine, hexadecylamine, hexadecylamine, decylamine, octylamine, didecylamine ( Didecylamine) and trioctylamine (Trioctylamine).
  • the fatty acid is characterized in that it contains at least one selected from lauric acid, oleic acid, stearic acid, palmitic acid and acetic acid. .
  • the glass frit is characterized by being coated with an organic solvent or an aqueous solution in which fatty amines or fatty acids having a concentration of 0.1 to 0.3% are dissolved.
  • the present invention in the solar cell having a front electrode on the top of the substrate, and a back electrode on the bottom of the substrate, the front electrode, the solar cell electrode is prepared by drying and firing after applying the conductive paste It provides a solar cell.
  • the conductive paste according to the present invention may include a glass frit coated with a fatty amine and a fatty acid to improve dispersibility, and uniform application of the glass frit during electrode formation may be possible. Accordingly, the reactivity at the time of firing is excellent, and particularly, the damage of the n layer can be minimized at a high temperature, the adhesion is improved, and the open voltage can be excellent. In addition, it is possible to easily and uniformly penetrate metal powder (eg, silver powder) during firing, thereby reducing the contact resistance between the electrode and the n layer. As a result, the electrical characteristics of the solar cell electrode can be improved, thereby improving the power generation efficiency of the solar cell.
  • metal powder eg, silver powder
  • 1 to 3 are images taken immediately after stirring after putting the coated glass frit and the uncoated glass frit in water according to the manufacturing example, and after leaving for 60 minutes and 24 hours.
  • FIG. 4 shows the results of thermogravimetric analysis on the surface coated glass frits and the uncoated glass frits prepared according to the manufacturing example.
  • Figure 6 shows the results of measuring the adhesion between the ribbon and the solar cell electrode manufactured using a conductive paste prepared according to Examples and Comparative Examples.
  • the terms comprise, comprises, comprising means referring to an article, step or group of articles, and steps, and any other article It is not meant to exclude a step or group of things or a group of steps.
  • the paste according to an embodiment of the present invention is a paste suitable for use in forming a solar cell electrode, and provides a conductive paste comprising a glass frit coated with fatty amine and fatty acid. More specifically, the conductive paste according to the present invention comprises a metal powder, glass frit, organic vehicle and other additives.
  • metal powder silver powder, copper powder, nickel powder, aluminum powder, etc. may be used.
  • silver powder is mainly used, and for the back electrode, aluminum powder is mainly used.
  • metal powder one of the above-described powders may be used alone, an alloy of the above-mentioned metals may be used, or a mixed powder in which at least two of the above-mentioned powders are mixed.
  • the content of the metal powder is preferably 40 to 95% by weight based on the total weight of the conductive paste composition, considering the electrode thickness formed during printing and the line resistance of the electrode. If it is less than 40% by weight, the specific resistance of the formed electrode may be high, and if it is more than 95% by weight, the content of other components is not sufficient, and thus there is a problem that the metal powder is not uniformly dispersed. More preferably, it is preferably included in 70 to 90% by weight.
  • silver powder is preferably a silver powder, in addition, a silver-coated composite powder composed of a silver layer or an alloy containing silver as a main component. (alloy) and the like. Further, other metal powders may be mixed and used. Examples include aluminum, gold, palladium, copper, and nickel.
  • the average particle diameter (D50) of the metal powder may be 0.1 to 10 ⁇ m, and 0.5 to 5 ⁇ m is preferable in consideration of easiness of pasting and density during firing, and its shape is at least 1 of spherical, acicular, plate-like, and amorphous. It may be more than a species.
  • the metal powder may be used by mixing two or more kinds of powders having different average particle diameters, particle size distributions, and shapes.
  • the glass frit may be coated with fatty amine and fatty acid to improve dispersibility. More specifically, the glass frit may be a primary coating of the fatty amine or fatty acid, and a secondary coating of the fatty acid or fatty acid.
  • the fatty amine includes an alkylamine-based material having 6 to 24 carbon atoms. More preferably, the surface of the glass frit may be coated with an alkylamine-based material having 10 to 20 carbon atoms.
  • the alkylamine-based material is triethylamine, heptylamine, octadecylamine, hexadecylamine, hexadecylamine, decylamine, octylamine, dideamine It may include at least one selected from diamine (Didecylamine) and trioctylamine (Trioctylamine).
  • the fatty acid may include at least one selected from lauric acid, oleic acid, stearic acid, palmitic acid and acetic acid.
  • the surface of the glass frit is coated with a thickness of 0.5 nm to 50 nm.
  • the coating of the fatty amine may be carried out by adding a glass frit into an organic solvent or aqueous solution (coating agent) in which the fatty amine is dissolved, followed by stirring for a certain period of time, followed by filtration.
  • the thickness of the coating layer formed by the coating process of the fatty amine is less than 0.5 nm, the effect of improving the dispersibility of the glass frit is reduced, and when the thickness of the coating layer is greater than 50 nm, the electricality of the electrode of the solar cell formed of a conductive paste containing it Characteristics may deteriorate.
  • the thickness of the coating layer can be adjusted through the content of fatty amines used in the coating process. For example, the concentration of the coating agent may be prepared in a range of 0.1 to 0.3% to control the thickness of the coating layer.
  • the surface of the glass frit is coated with a thickness of 0.5nm to 50nm.
  • the coating of the fatty acid may be carried out by adding a glass frit into an organic solvent or an aqueous solution (coating agent) in which the fatty acid is dissolved, followed by stirring for a certain period of time, followed by filtration.
  • the thickness of the coating layer formed by the coating treatment of the fatty acid is less than 0.5 nm, the effect of improving the dispersibility of the glass frit is reduced, and when the thickness of the coating layer is greater than 50 nm, the electrical properties of the electrode of the solar cell formed of a conductive paste containing it This can degrade.
  • the thickness of the coating layer can be adjusted through the content of fatty acids used in the coating process. For example, the concentration of the coating agent may be prepared in a range of 0.1 to 0.3% to control the thickness of the coating layer.
  • the glass frit is primarily coated with fatty amine, and it is preferable to use a glass frit secondary coated with fatty amine or fatty acid.
  • fatty amines When primary coating is performed using fatty amines, the dispersibility is improved to reduce the reaching phenomenon and the power generation efficiency of the solar cell increases by increasing the short-circuit current and open voltage.
  • a glass frit coated first with fatty amine and second coated with fatty acid More preferably, it is preferable to use a glass frit coated first with fatty amine and second coated with fatty acid.
  • the fatty acid is secondarily coated and coated on the outermost side, the coated content increases, and when coated, it has hydrophilicity and maintains dispersibility. Double coating with fatty amines and fatty acids can provide the best adhesion.
  • the composition, particle size and shape of the glass frit are not particularly limited. Leaded glass frits as well as leaded glass frits can be used. Preferably as a component and content of the glass frit, PbO is 5 to 29 mol%, TeO 2 is 20 to 34 mol%, Bi 2 O 3 is 3 to 20 mol%, SiO 2 20 mol% or less based on oxide conversion, B 2 O 3 10 mol% or less, alkali metals (Li, Na, K, etc.) and alkaline earth metals (Ca, Mg, etc.) preferably contain 10 to 20 mol%.
  • the combination of the organic content of each component prevents an increase in the line width of the electrode, can improve contact resistance at high surface resistance, and can provide excellent short-circuit current characteristics.
  • the average particle size of the glass frit is not limited, but may have a particle size within the range of 0.5 to 10 ⁇ m, and may be used by mixing multi-paper particles having different average particle sizes.
  • at least one glass frit having an average particle diameter (D50) of 2 ⁇ m or more and 10 ⁇ m or less is preferable.
  • the content of the glass frit is preferably 1 to 10% by weight based on the total weight of the conductive paste composition, and if it is less than 1% by weight, there is a possibility that the electrical resistivity is increased due to incomplete firing, and when it exceeds 10% by weight, glass in the fired body of the metal powder There is a concern that the electrical resistivity also increases due to too many components.
  • the surface of the glass frit is coated with fatty amines and fatty acids, dispersibility is improved, and when the electrode is formed, uniform application of the glass frit may be possible.
  • the reactivity at the time of firing is excellent, in particular, the damage of the n layer can be minimized at high temperature, the adhesion is improved, and the open voltage (Voc) can be excellent.
  • the metal powder eg, silver powder
  • Providing such an effect may provide an additional effect that makes it easier to control the composition, particle size, or shape of the glass frit.
  • the organic vehicle is not limited, but may include an organic binder and a solvent. Sometimes solvents can be omitted.
  • the organic vehicle is not limited, but is preferably 1 to 30% by weight based on the total weight of the conductive paste composition.
  • the organic vehicle is required to maintain a uniform mixture of metal powder and glass frit, for example, when the conductive paste is applied to the substrate by screen printing, the conductive paste is homogenized, and the printed pattern is blurred. And properties that suppress flow and further improve the dischargeability and plate separation properties of the conductive paste from the screen plate.
  • the organic binder contained in the organic vehicle is not limited, but examples of the cellulose ester-based compound include cellulose acetate and cellulose acetate butylate, and cellulose ether compounds include ethyl cellulose, methyl cellulose, hydroxy flopil cellulose, and hydroxy ethyl Examples include cellulose, hydroxy propyl methyl cellulose, and hydroxy ethyl methyl cellulose.
  • examples of the acrylic compound include poly acrylamide, poly methacrylate, poly methyl methacrylate, and poly ethyl methacrylate.
  • Vinyl-based examples include polyvinyl butyral, polyvinyl acetate and polyvinyl alcohol.
  • the organic binders may be selected and used at least one.
  • Solvents used for dilution of the composition include alpha-terpineol, texanol, dioctyl phthalate, dibutyl phthalate, cyclohexane, hexane, toluene, benzyl alcohol, dioxane, diethylene glycol, ethylene glycol monobutyl ether, ethylene It is preferable to use at least one selected from compounds consisting of glycol monobutyl ether acetate, diethylene glycol monobutyl ether, and diethylene glycol monobutyl ether acetate.
  • the conductive paste composition according to the present invention may further include additives commonly known as necessary, for example, dispersants, plasticizers, viscosity modifiers, surfactants, oxidizing agents, metal oxides, metal organic compounds, and the like.
  • the above-described conductive paste composition for a solar cell electrode may be prepared by mixing and dispersing a metal powder, a coated glass frit, an organic vehicle and additives, and then filtering and defoaming.
  • the present invention also provides a method for forming an electrode of a solar cell, characterized in that the conductive paste is applied onto a substrate, dried and fired, and a solar cell electrode produced by the method. Except for using a conductive paste containing a glass frit coated as described above in the method of forming a solar cell electrode of the present invention, substrates, printing, drying and firing can be used methods commonly used in the manufacture of solar cells. Yes, of course.
  • the substrate may be a silicon wafer.
  • a unit solar cell including a solar cell electrode formed as described above has a small electromotive force, so a plurality of unit solar cell cells are connected to form and use a solar cell module (Photovoltaic Module) having an appropriate electromotive force.
  • each unit solar cell is connected by conductor ribbons of a certain length coated with lead.
  • the conductive paste according to the present invention includes structures such as crystalline solar cells (P-type, N-type), PESC (Passivated Emitter Solar Cell), PERC (Passivated Emitter and Rear Cell), and PERL (Passivated Emitter Real Locally Diffused), and It can be applied to all of the changed printing processes such as double printing and dual printing.
  • structures such as crystalline solar cells (P-type, N-type), PESC (Passivated Emitter Solar Cell), PERC (Passivated Emitter and Rear Cell), and PERL (Passivated Emitter Real Locally Diffused), and It can be applied to all of the changed printing processes such as double printing and dual printing.
  • Preparation Example 1 a glass frit coated with stearic acid was obtained in the same manner as in Preparation Example 1, except that stearic acid was dissolved in ethanol to prepare an organic solution having a concentration of 0.3%.
  • coated glass frit, an organic binder, a solvent and a dispersant are added and dispersed using a mixing mixer, and then silver powder (spherical, average particle diameter 1 ⁇ m) The mixture was also dispersed using a sambon mill. Then, degassing under reduced pressure was carried out to prepare a conductive paste.
  • Examples 1 to 6 used the glass frit obtained according to Preparation Examples 1 to 6, respectively, and Comparative Example 1 used a glass frit of Pb-Te-Bi type not coated.
  • Example 2 Example 3
  • Example 4 Example 5
  • Example 6 Comparative Example 1
  • FIG. 4 shows the results of thermogravimetric analysis on the surface coated glass frits and the uncoated glass frits prepared according to Preparation Examples 1 to 6, and FIG. 5 shows a photographed image after performing thermogravimetric analysis.
  • FIG. 4 it is confirmed that the weight reduction width is increased according to the content (concentration) of the coating agent, and it can be seen that the coating is uniform.
  • the secondary coating with fatty acids Production Examples 4 and 6
  • black xanthan occurred on the glass surface as the coating content increased, which means that the coating was well performed.
  • a conductor ribbon was attached to the electrodes of each cell through a tabbing process.
  • the ribbon used was a product of 60Sn40Pb (kosbon), and was attached at 350°C using an ironing machine. Thereafter, the adhesion between the solar cell electrode and the ribbon was measured.
  • the adhesive force measuring device is LS1 (Lloyd), and the adhesive force was measured at a speed of 250 mm/min in the 180 degree direction. 6 shows a result of measuring adhesion between a solar cell electrode and a ribbon manufactured using a conductive paste prepared according to Examples and Comparative Examples. Referring to FIG.
  • Preparation Examples 1, 3, and 4 coated with fatty amines have improved dispersibility and uniform adhesion
  • Preparation Examples 2, 5, and 6 coated with fatty acids are powdered. It can be seen that the acidity is lowered and the adhesion is uneven.
  • the adhesion is determined according to the primary coating type, and it can be seen that the adhesion is best when the primary coating with fatty amine and secondary coating with fatty acid (Production Example 4).
  • the conductive pastes prepared according to Examples 1 to 6 and Comparative Example 1 were pattern printed on the front surface of the wafer by a screen printing technique of 40 ⁇ m mesh, and using a belt-type drying furnace at 200 to 350° C. for 20 to 30 seconds. It was dried. After that, Al paste was printed on the back side of the wafer and dried in the same way. Cells formed in the above process were calcined for 20 to 30 seconds between 500 and 900°C using a belt-type calcination furnace to produce a solar cell.
  • the manufactured cell uses solar cell efficiency measurement equipment (Halm, cetisPV-Celltest 3), short circuit current (Isc), open voltage (Voc), conversion efficiency (Eff), curve factor (FF), series resistance ( Rs) and line resistance (Rline) are measured and are shown in Table 2 below.
  • Example 1 10.0872 0.6631 22.238 80.516 0.00073 832 26.8 27.0
  • Example 1 10.1058 0.6641 22.311 80.551 0.00078 389 27.2 27.8
  • Example 2 10.0839 0.6629 22.230 80.546 0.00075 393 26.7 28.5
  • Example 3 10.1077 0.6639 22.297 80.583 0.00076 555 27.4 28.4
  • Example 4 10.1097 0.6647 22.323 80.582 0.00077 606 27.8 28.1
  • Example 5 10.0859 0.6631 22.250 80.576 0.00080 592 26.8 28.7
  • Example 6 10.0939 0.6629 22.229 80.458 0.00079 775 27.3 27.8

Abstract

The present invention provides a conductive paste for a solar cell electrode, the conductive paste comprising metal powder, a glass frit, and an organic vehicle, wherein the surface of the glass frit is coated with an aliphatic amine and a fatty acid, and thus the present invention improves dispersability so as to improve the electrical property of a solar cell electrode formed using same, thereby enabling the power generation efficiency of a solar cell to be enhanced.

Description

태양전지 전극용 도전성 페이스트 및 이를 사용하여 제조된 태양전지Conductive paste for solar cell electrodes and solar cell manufactured using the same
본 발명은 태양전지의 전극 형성에 사용되는 도전성 페이스트 및 이를 이용하여 제조된 태양전지에 관한 것이다.The present invention relates to a conductive paste used for forming an electrode of a solar cell and a solar cell manufactured using the conductive paste.
태양 전지(solar cell)는 태양에너지를 전기에너지로 변환시켜 주는 반도체 소자로서 일반적으로 p-n 접합 형태를 가지며 그 기본 구조는 다이오드와 동일하다. 태양 전지 소자는 일반적으로 두께가 180~250㎛인 p형 실리콘 반도체 기판을 이용하여 구성된다. 실리콘 반도체 기판의 수광면측에는, 두께가 0.3~0.6㎛인 n형 불순물층과, 그 위에 반사 방지막과 전면 전극이 형성되어 있다. 또한, p형 실리콘 반도체 기판의 이면측에는 배면 전극이 형성되어 있다. A solar cell is a semiconductor device that converts solar energy into electrical energy, and generally has a p-n junction type, and its basic structure is the same as that of a diode. The solar cell device is generally constructed using a p-type silicon semiconductor substrate having a thickness of 180 to 250 μm. On the light-receiving surface side of the silicon semiconductor substrate, an n-type impurity layer having a thickness of 0.3 to 0.6 µm, an antireflection film and a front electrode are formed thereon. In addition, a back electrode is formed on the back side of the p-type silicon semiconductor substrate.
전면 전극은 은을 주성분으로 하는 도전성 입자(silver powder), 유리 프릿(glass frit), 유기 비히클(organic vehicle), 및 첨가제 등을 혼합한 도전성 페이스트를 반사 방지막 상에 도포한 후 소성하여 전극을 형성하고 있으며, 배면 전극은 알루미늄 분말, 유리 프릿, 유기 비히클 및 첨가제로 이루어지는 알루미늄 페이스트 조성물을 스크린 인쇄 등에 의해 도포하고 건조한 후, 660℃(알루미늄의 융점) 이상의 온도에서 소성함으로써 형성되어 있다. 이 소성시에 알루미늄이 p형 실리콘 반도체 기판의 내부로 확산됨으로써, 배면 전극과 p형 실리콘 반도체 기판 사이에 Al-Si 합금층이 형성됨과 동시에, 알루미늄 원자의 확산에 의한 불순물층으로서 p+층이 형성된다. 이러한 p+층의 존재에 의해 전자의 재결합을 방지하고, 생성 캐리어의 수집 효율을 향상시키는 BSF(Back Surface Field) 효과가 얻어진다. 배면 알루미늄 전극 하부에는 배면 실버 전극이 더 위치될 수 있다.The front electrode is coated with a conductive paste containing silver-based conductive powder (silver powder), glass frit, organic vehicle, and additives on an anti-reflection film, followed by firing to form an electrode. The back electrode is formed by applying an aluminum paste composition composed of aluminum powder, glass frit, organic vehicle and additives by screen printing and drying, followed by baking at a temperature of 660° C. (melting point of aluminum) or higher. During the firing, aluminum diffuses into the p-type silicon semiconductor substrate, whereby an Al-Si alloy layer is formed between the back electrode and the p-type silicon semiconductor substrate, and at the same time, a p+ layer is formed as an impurity layer by diffusion of aluminum atoms. do. The presence of the p+ layer prevents recombination of electrons and obtains a back surface field (BSF) effect that improves the collection efficiency of the resulting carrier. A rear silver electrode may be further positioned under the rear aluminum electrode.
한편, 유리 프릿은 실리콘 웨이퍼(Si-wafer)의 표면에 코팅되어 있는 반사 방지막 층(SiNx)을 식각하여 웨이퍼의 n층과 전면전극의 Ag가 오믹컨택(ohmic contact)을 형성하게 함으로써 태양전지의 회로를 형성하고 효율을 증가시키며 부착력을 증대하여 신뢰성을 확보하는 역할을 하기 때문에 실리콘 태양전지의 Ag/Si 접촉을 위해 필수적이다. On the other hand, the glass frit etched the anti-reflection layer (SiNx) coated on the surface of the silicon wafer (Si-wafer) so that the n-layer of the wafer and Ag of the front electrode form an ohmic contact, thereby making the solar cell It is essential for Ag/Si contact of silicon solar cells because it serves to secure reliability by forming circuits, increasing efficiency, and increasing adhesion.
태양전지의 고효율 특성 구현 때문에, 접촉저항(Rc)이 우수한 유리 프릿의 사용이 불가피한 상황이다. 종래의 경우, 유리 프릿의 성분계, 입자 크기, 또는 함량을 조절함으로써 반사 방지막의 식각을 제어하였으나, 유리 프릿의 분산에 있어서 많은 문제점이 야기되었다. 또한 소결 후 이미지 관찰 시 유리층의 두께가 균일하지 못하여 두꺼운 영역에서는 n층에 손상이 발생되고, 얇은 영역에서는 은 분말의 침투가 적어짐으로써 전류가 감소되거나 저항이 증가하는 문제가 발생한다.Due to the implementation of high efficiency characteristics of the solar cell, it is inevitable to use a glass frit having excellent contact resistance (Rc). In the conventional case, the etching of the antireflection film was controlled by adjusting the component system, particle size, or content of the glass frit, but many problems were caused in the dispersion of the glass frit. In addition, when the image is observed after sintering, the thickness of the glass layer is not uniform, so that the n layer is damaged in the thick region, and the penetration of silver powder decreases in the thin region, resulting in a decrease in current or an increase in resistance.
(특허문헌 1) 미국등록특허 8,748,327 B1 (2014.06.10.)(Patent Document 1) U.S. Patent Registration 8,748,327 B1 (2014.06.10.)
(특허문헌 2) WO공개특허 2013/105812 A1 (2013.07.18.)(Patent Document 2) WO Publication Patent 2013/105812 A1 (2013.07.18.)
(특허문헌 3) 미국공개특허 2011-0094578 A1 (2011.04.28.)(Patent Document 3) US Patent Publication 2011-0094578 A1 (2011.04.28.)
본 발명은 태양전지 전극용 도전성 페이스트의 조성 중 유리 프릿의 표면을 코팅하여 분산성을 향상시킴으로써, 이를 이용하여 형성된 태양전지 전극의 전기적 특성을 개선시켜 태양전지의 발전효율을 향상시키는 것을 목적으로 한다.The present invention aims to improve the power generation efficiency of a solar cell by improving the electrical properties of the solar cell electrode formed by coating the surface of the glass frit in the composition of the conductive paste for solar cell electrodes to improve dispersibility. .
그러나 본 발명의 목적들은 상기에 언급된 목적으로 제한되지 않으며, 언급되지 않은 또 다른 목적들은 아래의 기재로부터 당업자에게 명확하게 이해될 수 있을 것이다.However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.
본 발명은 금속 분말, 유리 프릿, 및 유기 비히클을 포함하되, 상기 유리 프릿의 표면은 지방아민 및 지방산으로 코팅 처리된 것을 특징으로 하는 태양전지 전극용 도전성 페이스트를 제공한다. The present invention provides a conductive paste for a solar cell electrode comprising a metal powder, a glass frit, and an organic vehicle, wherein the surface of the glass frit is coated with fatty amine and fatty acid.
또한 상기 유리 프릿은 상기 지방아민 또는 지방산으로 1차 코팅되고, 상기 지방아민 또는 지방산으로 2차 코팅처리된 것을 특징으로 한다.In addition, the glass frit is characterized in that the primary coating with the fatty amine or fatty acid, the secondary coating with the fatty amine or fatty acid.
또한 상기 유리 프릿은 지방아민으로 1차 코팅되고, 지방아민 또는 지방산으로 2차 코팅된 유리 프릿을 사용하는 것을 특징으로 한다.In addition, the glass frit is characterized by using a glass frit primary coated with fatty amine and secondary coated with fatty amine or fatty acid.
또한 상기 유리 프릿은 지방아민으로 1차 코팅되고, 지방산으로 2차 코팅된 유리 프릿을 사용하는 것을 특징으로 하는 한다.In addition, the glass frit is characterized by using a glass frit primary coated with fatty amines and secondary coated with fatty acids.
또한 상기 지방아민은 탄소수 6 내지 24의 알킬아민계 물질을 포함하는 것을 특징으로 한다.In addition, the fatty amine is characterized in that it comprises an alkylamine-based material having 6 to 24 carbon atoms.
또한 상기 알킬아민계 물질은 트리에틸아민(Triethylamine), 헵틸아민(Heptylamine), 옥타데실아민(Octadecylamine), 헥사데실아민(Hexadecylamine), 데실아민(Decylamine), 옥틸아민(Octylamine), 디데실아민(Didecylamine) 및 트리옥틸아민(Trioctylamine) 중에서 선택된 적어도 하나를 포함하는 것을 특징으로 한다.In addition, the alkylamine-based material is triethylamine, heptylamine, octadecylamine, hexadecylamine, hexadecylamine, decylamine, octylamine, didecylamine ( Didecylamine) and trioctylamine (Trioctylamine).
또한 상기 지방산은 라우르산(Lauric acid), 올레익산(Oleic acid), 스테아릭산(Stearic acid), 팔미트산(Palmitic acid) 및 아세트산(Acetic acid) 중에서 선택된 적어도 하나를 포함하는 것을 특징으로 한다.In addition, the fatty acid is characterized in that it contains at least one selected from lauric acid, oleic acid, stearic acid, palmitic acid and acetic acid. .
또한 상기 유리 프릿은 농도가 0.1 내지 0.3%인 지방아민 또는 지방산이 녹아있는 유기 용매 또는 수용액으로 코팅된 것을 특징으로 한다.In addition, the glass frit is characterized by being coated with an organic solvent or an aqueous solution in which fatty amines or fatty acids having a concentration of 0.1 to 0.3% are dissolved.
또한 본 발명은 기재 상부에 전면 전극을 구비하고, 기재 하부에 배면 전극을 구비한 태양전지에 있어서, 상기 전면 전극은, 상기 태양전지 전극용 도전성 페이스트를 도포한 후 건조 및 소성시켜 제조된 것을 특징으로 하는 태양전지를 제공한다.In addition, the present invention in the solar cell having a front electrode on the top of the substrate, and a back electrode on the bottom of the substrate, the front electrode, the solar cell electrode is prepared by drying and firing after applying the conductive paste It provides a solar cell.
본 발명에 따른 도전성 페이스트는 분산성의 향상을 위해 지방아민 및 지방산으로 코팅 처리된 유리 프릿을 포함하여, 전극 형성 시 유리 프릿의 균일한 도포가 가능할 수 있다. 이에 따라, 소성시 반응성이 우수해지고, 특히 고온에서 n층의 데미지를 최소화할 수 있으며 부착력이 개선되고 개방전압을 우수하게 할 수 있다. 또한, 소성시 금속 분말(예컨대, 은 분말)의 침투가 용이하고 균일하게 하여 전극과 n층의 접촉 저항을 감소시킬 수 있다. 결과적으로 태양전지 전극의 전기적 특성이 개선되어 태양전지의 발전효율이 향상될 수 있다.The conductive paste according to the present invention may include a glass frit coated with a fatty amine and a fatty acid to improve dispersibility, and uniform application of the glass frit during electrode formation may be possible. Accordingly, the reactivity at the time of firing is excellent, and particularly, the damage of the n layer can be minimized at a high temperature, the adhesion is improved, and the open voltage can be excellent. In addition, it is possible to easily and uniformly penetrate metal powder (eg, silver powder) during firing, thereby reducing the contact resistance between the electrode and the n layer. As a result, the electrical characteristics of the solar cell electrode can be improved, thereby improving the power generation efficiency of the solar cell.
도 1 내지 3은 제조예에 따라 코팅된 유리 프릿과 무코팅 유리 프릿을 물에 넣고 교반한 직후와 60분, 24시간 방치시킨 후의 상태를 촬영한 이미지이다.1 to 3 are images taken immediately after stirring after putting the coated glass frit and the uncoated glass frit in water according to the manufacturing example, and after leaving for 60 minutes and 24 hours.
도 4는 제조예에 따라 제조된 표면 코팅 유리 프릿들과 무코팅 유리 프릿에 대해 열중량분석을 수행한 결과를 나타낸 것이다.FIG. 4 shows the results of thermogravimetric analysis on the surface coated glass frits and the uncoated glass frits prepared according to the manufacturing example.
도 5는 상기 열중량분석 후 촬영한 유리 프릿 이미지를 나타낸 것이다. 5 shows a glass frit image taken after the thermogravimetric analysis.
도 6은 실시예 및 비교예에 따라 제조된 도전성 페이스트를 이용하여 제조된 태양전지 전극과 리본 사이의 부착력 측정 결과를 나타낸 것이다.Figure 6 shows the results of measuring the adhesion between the ribbon and the solar cell electrode manufactured using a conductive paste prepared according to Examples and Comparative Examples.
도 7은 실시예 및 비교예에 따라 제조된 도체 리본의 탈착 후 촬영한 전극의 표면 이미지들이다.7 are surface images of an electrode photographed after desorption of a conductor ribbon manufactured according to Examples and Comparative Examples.
이하에 본 발명을 상세하게 설명하기에 앞서, 본 명세서에 사용된 용어는 특정의 실시예를 기술하기 위한 것일 뿐 첨부하는 특허청구의 범위에 의해서만 한정되는 본 발명의 범위를 한정하려는 것은 아님을 이해하여야 한다. 본 명세서에 사용되는 모든 기술용어 및 과학용어는 다른 언급이 없는 한은 기술적으로 통상의 기술을 가진 자에게 일반적으로 이해되는 것과 동일한 의미를 가진다.Before describing the present invention in detail below, it is understood that the terms used herein are only for describing specific embodiments and are not intended to limit the scope of the present invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art unless otherwise stated.
본 명세서 및 청구범위의 전반에 걸쳐, 다른 언급이 없는 한 포함(comprise, comprises, comprising)이라는 용어는 언급된 물건, 단계 또는 일군의 물건, 및 단계를 포함하는 것을 의미하고, 임의의 어떤 다른 물건, 단계 또는 일군의 물건 또는 일군의 단계를 배제하는 의미로 사용된 것은 아니다.Throughout this specification and claims, unless otherwise stated, the terms comprise, comprises, comprising means referring to an article, step or group of articles, and steps, and any other article It is not meant to exclude a step or group of things or a group of steps.
한편, 본 발명의 여러 가지 실시예들은 명확한 반대의 지적이 없는 한 그 외의 어떤 다른 실시예들과 결합될 수 있다. 특히 바람직하거나 유리하다고 지시하는 어떤 특징도 바람직하거나 유리하다고 지시한 그 외의 어떤 특징 및 특징들과 결합될 수 있다. 이하, 첨부된 도면을 참조하여 본 발명의 실시예 및 이에 따른 효과를 설명하기로 한다.On the other hand, various embodiments of the present invention can be combined with any other embodiments, unless otherwise indicated. Any feature indicated as particularly preferred or advantageous may be combined with any other feature or features indicated as preferred or advantageous. Hereinafter, embodiments and effects according to the present invention will be described with reference to the accompanying drawings.
본 발명의 일실시예에 따른 페이스트는 태양전지 전극 형성에 사용되기 적합한 페이스트로서, 지방아민 및 지방산으로 코팅 처리된 유리 프릿(glass frit)을 포함하는 도전성 페이스트를 제공한다. 더욱 구체적으로 본 발명에 따른 도전성 페이스트는 금속 분말, 유리 프릿, 유기 비히클 및 기타 첨가제를 포함하여 이루어진다. The paste according to an embodiment of the present invention is a paste suitable for use in forming a solar cell electrode, and provides a conductive paste comprising a glass frit coated with fatty amine and fatty acid. More specifically, the conductive paste according to the present invention comprises a metal powder, glass frit, organic vehicle and other additives.
상기 금속 분말로는 은 분말, 구리 분말, 니켈 분말, 알루미늄 분말 등이 사용될 수 있는데, 전면 전극용의 경우 은 분말이 주로 사용되며, 배면 전극용은 주로 알루미늄 분말이 사용된다. 금속 분말은 상술한 분말 중 하나가 단독으로 사용되거나, 상술한 금속의 합금이 사용되거나, 상술한 분말 중 적어도 두 개가 혼합된 혼합 분말로 사용될 수 있다. As the metal powder, silver powder, copper powder, nickel powder, aluminum powder, etc. may be used. In the case of the front electrode, silver powder is mainly used, and for the back electrode, aluminum powder is mainly used. As the metal powder, one of the above-described powders may be used alone, an alloy of the above-mentioned metals may be used, or a mixed powder in which at least two of the above-mentioned powders are mixed.
금속 분말의 함량은 인쇄 시 형성되는 전극 두께 및 전극의 선저항을 고려할 때 도전성 페이스트 조성물 총 중량을 기준으로 40 내지 95 중량%가 바람직하다. 40 중량% 미만인 경우 형성된 전극의 비저항이 높을 수 있으며, 95 중량% 초과인 경우 다른 성분의 함량이 충분하지 않아 금속 분말이 균일하게 분산되지 않는 문제점이 있다. 더욱 바람직하게는 70 내지 90 중량%로 포함되는 것이 좋다.The content of the metal powder is preferably 40 to 95% by weight based on the total weight of the conductive paste composition, considering the electrode thickness formed during printing and the line resistance of the electrode. If it is less than 40% by weight, the specific resistance of the formed electrode may be high, and if it is more than 95% by weight, the content of other components is not sufficient, and thus there is a problem that the metal powder is not uniformly dispersed. More preferably, it is preferably included in 70 to 90% by weight.
태양전지의 전면 전극 형성을 위하여 도전성 페이스트가 은 분말을 포함하는 경우 은 분말은 순은 분말이 바람직하며, 이외에 적어도 표면이 은 층(silver layer)으로 이루어지는 은 피복 복합 분말이나, 은을 주성분으로 하는 합금(alloy) 등을 사용할 수 있다. 또한, 다른 금속 분말을 혼합하여 사용할 수도 있다. 예를 들면 알루미늄, 금, 팔라듐, 동, 니켈 등을 들 수 있다.In order to form the front electrode of the solar cell, when the conductive paste contains silver powder, silver powder is preferably a silver powder, in addition, a silver-coated composite powder composed of a silver layer or an alloy containing silver as a main component. (alloy) and the like. Further, other metal powders may be mixed and used. Examples include aluminum, gold, palladium, copper, and nickel.
금속 분말의 평균 입경(D50)은 0.1 내지 10㎛ 일 수 있으며, 페이스트화 용이성 및 소성시 치밀도를 고려할 때 0.5 내지 5㎛가 바람직하며, 그 형상이 구상, 침상, 판상 그리고 무정상 중 적어도 1종 이상일 수 있다. 금속 분말은 평균 입자지름이나 입도 분포, 형상 등이 다른 2종 이상의 분말을 혼합하여 이용해도 좋다. The average particle diameter (D50) of the metal powder may be 0.1 to 10 µm, and 0.5 to 5 µm is preferable in consideration of easiness of pasting and density during firing, and its shape is at least 1 of spherical, acicular, plate-like, and amorphous. It may be more than a species. The metal powder may be used by mixing two or more kinds of powders having different average particle diameters, particle size distributions, and shapes.
상기 유리 프릿은 분산성의 향상을 위해 지방아민 및 지방산으로 코팅 처리될 수 있다. 더욱 구체적으로 상기 유리 프릿은 상기 지방아민 또는 지방산으로 1차 코팅되고, 상기 지방민 또는 지방산으로 2차 코팅처리된 것을 사용할 수 있다. The glass frit may be coated with fatty amine and fatty acid to improve dispersibility. More specifically, the glass frit may be a primary coating of the fatty amine or fatty acid, and a secondary coating of the fatty acid or fatty acid.
상기 지방아민은 탄소수 6 내지 24의 알킬아민계 물질을 포함한다. 더욱 바람직하게, 상기 유리 프릿의 표면은 탄소수 10 내지 20의 알킬아민계 물질로 코팅 처리될 수 있다. 예를 들어, 상기 알킬아민계 물질은 트리에틸아민(Triethylamine), 헵틸아민(Heptylamine), 옥타데실아민(Octadecylamine), 헥사데실아민(Hexadecylamine), 데실아민(Decylamine), 옥틸아민(Octylamine), 디데실아민(Didecylamine) 및 트리옥틸아민(Trioctylamine) 중에서 선택된 적어도 하나를 포함할 수 있다.The fatty amine includes an alkylamine-based material having 6 to 24 carbon atoms. More preferably, the surface of the glass frit may be coated with an alkylamine-based material having 10 to 20 carbon atoms. For example, the alkylamine-based material is triethylamine, heptylamine, octadecylamine, hexadecylamine, hexadecylamine, decylamine, octylamine, dideamine It may include at least one selected from diamine (Didecylamine) and trioctylamine (Trioctylamine).
상기 지방산은 라우르산(Lauric acid), 올레익산(Oleic acid), 스테아릭산(Stearic acid), 팔미트산(Palmitic acid) 및 아세트산(Acetic acid) 중에서 선택된 적어도 하나를 포함할 수 있다.The fatty acid may include at least one selected from lauric acid, oleic acid, stearic acid, palmitic acid and acetic acid.
상기 지방아민을 이용하여 코팅하는 경우 유리 프릿의 표면에 0.5nm 내지 50nm의 두께로 코팅되는 것이 바람직하다. 지방아민의 코팅은 지방아민이 녹아있는 유기 용매 또는 수용액(코팅제)에 유리 프릿을 넣고 일정시간 교반한 후 여과하는 방법으로 진행될 수 있다. 상기 지방아민의 코팅 처리에 의해 형성된 코팅층의 두께가 0.5nm 보다 작은 경우 유리 프릿의 분산성 향상 효과가 감소되고, 코팅층의 두께가 50nm 보다 큰 경우 이를 포함하는 도전성 페이스트로 형성된 태양전지의 전극의 전기적 특성이 저하될 수 있다. 상기 코팅층의 두께는 코팅 처리시 사용되는 지방아민의 함량을 통해 조절될 수 있다. 예를 들어 코팅제의 농도를 0.1 내지 0.3% 범위로 제조하여 코팅층의 두께를 조절할 수 있다. When coating using the fatty amine, it is preferable that the surface of the glass frit is coated with a thickness of 0.5 nm to 50 nm. The coating of the fatty amine may be carried out by adding a glass frit into an organic solvent or aqueous solution (coating agent) in which the fatty amine is dissolved, followed by stirring for a certain period of time, followed by filtration. When the thickness of the coating layer formed by the coating process of the fatty amine is less than 0.5 nm, the effect of improving the dispersibility of the glass frit is reduced, and when the thickness of the coating layer is greater than 50 nm, the electricality of the electrode of the solar cell formed of a conductive paste containing it Characteristics may deteriorate. The thickness of the coating layer can be adjusted through the content of fatty amines used in the coating process. For example, the concentration of the coating agent may be prepared in a range of 0.1 to 0.3% to control the thickness of the coating layer.
상기 지방산을 이용하여 코팅하는 경우 유리 프릿의 표면에 0.5nm 내지 50nm의 두께로 코팅되는 것이 바람직하다. 지방산의 코팅은 지방산이 녹아있는 유기 용매 또는 수용액(코팅제)에 유리 프릿을 넣고 일정시간 교반한 후 여과하는 방법으로 진행될 수 있다. 상기 지방산의 코팅 처리에 의해 형성된 코팅층의 두께가 0.5nm 보다 작은 경우 유리 프릿의 분산성 향상 효과가 감소되고, 코팅층의 두께가 50nm 보다 큰 경우 이를 포함하는 도전성 페이스트로 형성된 태양전지의 전극의 전기적 특성이 저하될 수 있다. 상기 코팅층의 두께는 코팅 처리시 사용되는 지방산의 함량을 통해 조절될 수 있다. 예를 들어 코팅제의 농도를 0.1 내지 0.3% 범위로 제조하여 코팅층의 두께를 조절할 수 있다.When coating using the fatty acid, it is preferable that the surface of the glass frit is coated with a thickness of 0.5nm to 50nm. The coating of the fatty acid may be carried out by adding a glass frit into an organic solvent or an aqueous solution (coating agent) in which the fatty acid is dissolved, followed by stirring for a certain period of time, followed by filtration. When the thickness of the coating layer formed by the coating treatment of the fatty acid is less than 0.5 nm, the effect of improving the dispersibility of the glass frit is reduced, and when the thickness of the coating layer is greater than 50 nm, the electrical properties of the electrode of the solar cell formed of a conductive paste containing it This can degrade. The thickness of the coating layer can be adjusted through the content of fatty acids used in the coating process. For example, the concentration of the coating agent may be prepared in a range of 0.1 to 0.3% to control the thickness of the coating layer.
바람직하게는 상기 유리 프릿은 지방아민으로 1차 코팅되고, 지방아민 또는 지방산으로 2차 코팅된 유리 프릿을 사용하는 것이 좋다. 지방아민을 이용하여 1차로 코팅 시 분산성이 향상되어 reaching 현상이 감소하고 단락전류 및 개방전압 상승에 의해 태양전지 발전효율이 상승한다. Preferably, the glass frit is primarily coated with fatty amine, and it is preferable to use a glass frit secondary coated with fatty amine or fatty acid. When primary coating is performed using fatty amines, the dispersibility is improved to reduce the reaching phenomenon and the power generation efficiency of the solar cell increases by increasing the short-circuit current and open voltage.
더욱 바람직하게는 지방아민으로 1차 코팅되고, 지방산으로 2차 코팅된 유리 프릿을 사용하는 것이 좋다. 지방산이 2차로 코팅되어 가장 바깥쪽에 코팅되는 경우 코팅된 함량이 증가하고, 코팅 시 친수성을 가지며 분산성을 유지한다. 지방아민 및 지방산으로 2중 코팅될 경우 가장 우수한 부착력을 제공할 수 있다. More preferably, it is preferable to use a glass frit coated first with fatty amine and second coated with fatty acid. When the fatty acid is secondarily coated and coated on the outermost side, the coated content increases, and when coated, it has hydrophilicity and maintains dispersibility. Double coating with fatty amines and fatty acids can provide the best adhesion.
상기 유리 프릿의 조성이나 입경, 형상에 있어서 특별히 제한을 두지 않는다. 유연 유리 프릿뿐만 아니라 무연 유리 프릿도 사용 가능하다. 바람직하기로는 유리 프릿의 성분 및 함량으로서, 산화물 환산 기준으로 PbO는 5 ~ 29 mol%, TeO2는 20 ~ 34 mol%, Bi2O3는 3 ~ 20 mol%, SiO2 20 mol% 이하, B2O3 10 mol% 이하, 알칼리 금속(Li, Na, K 등) 및 알칼리 토금속(Ca, Mg 등)은 10 ~ 20 mol%를 함유하는 것이 좋다. 상기 각 성분의 유기적 함량 조합에 의해 전극 선폭 증가를 막고 고면저항에서 접촉 저항을 우수하게 할 수 있으며, 단락전류 특성을 우수하게 할 수 있다. The composition, particle size and shape of the glass frit are not particularly limited. Leaded glass frits as well as leaded glass frits can be used. Preferably as a component and content of the glass frit, PbO is 5 to 29 mol%, TeO 2 is 20 to 34 mol%, Bi 2 O 3 is 3 to 20 mol%, SiO 2 20 mol% or less based on oxide conversion, B 2 O 3 10 mol% or less, alkali metals (Li, Na, K, etc.) and alkaline earth metals (Ca, Mg, etc.) preferably contain 10 to 20 mol%. The combination of the organic content of each component prevents an increase in the line width of the electrode, can improve contact resistance at high surface resistance, and can provide excellent short-circuit current characteristics.
유리 프릿의 평균 입경은 제한되지 않으나 0.5 내지 10㎛ 범위 내의 입경을 가질 수 있으며, 평균 입경이 다른 다종이 입자를 혼합하여 사용할 수도 있다. 바람직하기로는 적어도 1종의 유리 프릿은 평균 입경(D50)이 2㎛ 이상 10 ㎛ 이하인 것을 사용하는 것이 좋다. The average particle size of the glass frit is not limited, but may have a particle size within the range of 0.5 to 10 μm, and may be used by mixing multi-paper particles having different average particle sizes. Preferably, at least one glass frit having an average particle diameter (D50) of 2 µm or more and 10 µm or less is preferable.
유리 프릿의 함량은 도전성 페이스트 조성물 총중량을 기준으로 1 내지 10 중량%가 바람직한데, 1 중량% 미만이면 불완전 소성이 이루어져 전기 비저항이 높아질 우려가 있고, 10 중량% 초과하면 금속 분말의 소성체 내에 유리 성분이 너무 많아져 전기 비저항이 역시 높아질 우려가 있다.The content of the glass frit is preferably 1 to 10% by weight based on the total weight of the conductive paste composition, and if it is less than 1% by weight, there is a possibility that the electrical resistivity is increased due to incomplete firing, and when it exceeds 10% by weight, glass in the fired body of the metal powder There is a concern that the electrical resistivity also increases due to too many components.
상술한 바와 같이 유리 프릿의 표면이 지방아민 및 지방산으로 코팅 처리됨에 따라 분산성이 향상되어, 전극 형성 시 유리 프릿의 균일한 도포가 가능할 수 있다. 그 결과, 소성시 반응성이 우수해지고, 특히 고온에서 n층의 데미지를 최소화할 수 있으며 부착력이 개선되고 개방전압(Voc)을 우수하게 할 수 있다. 또한, 소성시 금속 분말(예컨대, 은 분말)의 침투를 균일하게 하여 전극과 n층의 접촉 저항을 감소시킬 수 있다. 이와 같은 효과의 제공은, 유리 프릿의 조성, 입경 또는 형상의 조절을 더욱 용이하게 하는 추가적인 효과를 제공할 수 있다.As described above, as the surface of the glass frit is coated with fatty amines and fatty acids, dispersibility is improved, and when the electrode is formed, uniform application of the glass frit may be possible. As a result, the reactivity at the time of firing is excellent, in particular, the damage of the n layer can be minimized at high temperature, the adhesion is improved, and the open voltage (Voc) can be excellent. In addition, it is possible to reduce the contact resistance between the electrode and the n layer by uniformly penetrating the metal powder (eg, silver powder) during firing. Providing such an effect may provide an additional effect that makes it easier to control the composition, particle size, or shape of the glass frit.
상기 유기 비히클로는 제한되지 않으나 유기 바인더와 용제 등이 포함될 수 있다. 때로는 용제가 생략될 수 있다. 유기 비히클은 제한되지 않으나 도전성 페이스트 조성물 총 중량을 기준으로 1 내지 30 중량%가 바람직하다.The organic vehicle is not limited, but may include an organic binder and a solvent. Sometimes solvents can be omitted. The organic vehicle is not limited, but is preferably 1 to 30% by weight based on the total weight of the conductive paste composition.
유기 비히클은 금속 분말과 유리 프릿 등이 균일하게 혼합된 상태를 유지하는 특성이 요구되며, 예를 들면 스크린 인쇄에 의해 도전성 페이스트가 기재에 도포될 때에, 도전성 페이스트를 균질하게 하여, 인쇄 패턴의 흐려짐 및 흐름을 억제하고, 또한 스크린판으로부터의 도전성 페이스트의 토출성 및 판분리성을 향상시키는 특성이 요구된다. The organic vehicle is required to maintain a uniform mixture of metal powder and glass frit, for example, when the conductive paste is applied to the substrate by screen printing, the conductive paste is homogenized, and the printed pattern is blurred. And properties that suppress flow and further improve the dischargeability and plate separation properties of the conductive paste from the screen plate.
유기 비히클에 포함되는 유기 바인더는 제한되지 않으나 셀룰로오스 에스테르계 화합물로 셀룰로오스 아세테이트, 셀룰로오스 아세테이트 부틸레이트 등을 예로 들 수 있으며, 셀룰로오스 에테르 화합물로는 에틸 셀룰로오스, 메틸 셀룰로오스, 하이드록시 플로필 셀룰로오스, 하이드록시 에틸 셀룰로오스, 하이드록시 프로필 메틸 셀룰로오스, 하이드록시 에틸 메틸 셀룰로오스 등을 예로 들 수 있으며, 아크릴계 화합물로는 폴리 아크릴아미드, 폴리 메타 아크릴레이트, 폴리 메틸 메타 아크릴레이트, 폴리 에틸 메타 아크릴레이트 등을 예로 들 수 있으며, 비닐계로는 폴리비닐 부티랄, 폴리비닐 아세테이트 그리고 폴리비닐 알코올 등을 예로 들 수 있다. 상기 유기 바인더들은 적어도 1종 이상 선택되어 사용될 수 있다. The organic binder contained in the organic vehicle is not limited, but examples of the cellulose ester-based compound include cellulose acetate and cellulose acetate butylate, and cellulose ether compounds include ethyl cellulose, methyl cellulose, hydroxy flopil cellulose, and hydroxy ethyl Examples include cellulose, hydroxy propyl methyl cellulose, and hydroxy ethyl methyl cellulose. Examples of the acrylic compound include poly acrylamide, poly methacrylate, poly methyl methacrylate, and poly ethyl methacrylate. , Vinyl-based examples include polyvinyl butyral, polyvinyl acetate and polyvinyl alcohol. The organic binders may be selected and used at least one.
조성물의 희석을 위해 사용되는 용제로서는 알파-터피네올, 텍사놀, 디옥틸 프탈레이트, 디부틸 프탈레이트, 시클로헥산, 헥산, 톨루엔, 벤질알코올, 디옥산, 디에틸렌글리콜, 에틸렌 글리콜 모노 부틸 에테르, 에틸렌 글리콜 모노 부틸 에테르 아세테이트, 디에틸렌 글리콜 모노 부틸 에테르, 디에틸렌 글리콜 모노 부틸 에테르 아세테이트 등으로 이루어진 화합물 중에서 적어도 1종 이상 선택되어 사용되는 것이 좋다.Solvents used for dilution of the composition include alpha-terpineol, texanol, dioctyl phthalate, dibutyl phthalate, cyclohexane, hexane, toluene, benzyl alcohol, dioxane, diethylene glycol, ethylene glycol monobutyl ether, ethylene It is preferable to use at least one selected from compounds consisting of glycol monobutyl ether acetate, diethylene glycol monobutyl ether, and diethylene glycol monobutyl ether acetate.
본 발명에 의한 도전성 페이스트 조성물은 필요에 따라 통상적으로 알려져 있는 첨가제, 예를 들면, 분산제, 가소제, 점도 조정제, 계면활성제, 산화제, 금속 산화물, 금속 유기 화합물 등을 더 포함할 수 있다.The conductive paste composition according to the present invention may further include additives commonly known as necessary, for example, dispersants, plasticizers, viscosity modifiers, surfactants, oxidizing agents, metal oxides, metal organic compounds, and the like.
상술한 태양전지 전극용 도전성 페이스트 조성물은 금속 분말, 코팅 처리된 유리 프릿, 유기 비히클 및 첨가제 등을 혼합 및 분산한 다음 여과 및 탈포하여 제조될 수 있다. The above-described conductive paste composition for a solar cell electrode may be prepared by mixing and dispersing a metal powder, a coated glass frit, an organic vehicle and additives, and then filtering and defoaming.
본 발명은 또한 상기 도전성 페이스트를 기재 위에 도포하고, 건조 및 소성하는 것을 특징으로 하는 태양전지의 전극 형성 방법 및 상기 방법에 의하여 제조된 태양전지 전극을 제공한다. 본 발명의 태양전지 전극 형성 방법에서 상기와 같이 코팅 처리된 유리 프릿을 포함하는 도전성 페이스트를 사용하는 것을 제외하고, 기재, 인쇄, 건조 및 소성은 통상적으로 태양전지의 제조에 사용되는 방법들이 사용될 수 있음은 물론이다. 일 예로 상기 기재는 실리콘 웨이퍼일 수 있다.The present invention also provides a method for forming an electrode of a solar cell, characterized in that the conductive paste is applied onto a substrate, dried and fired, and a solar cell electrode produced by the method. Except for using a conductive paste containing a glass frit coated as described above in the method of forming a solar cell electrode of the present invention, substrates, printing, drying and firing can be used methods commonly used in the manufacture of solar cells. Yes, of course. For example, the substrate may be a silicon wafer.
한편, 상기와 같이 형성된 태양전지 전극을 포함하는 단위 태양전지 셀은 그 기전력이 작기 때문에 다수의 단위 태양전지 셀을 연결하여 적정 기전력을 갖는 태양전지모듈(Photovoltaic Module)을 구성하여 사용하게 되는데, 이 때 각 단위 태양전지 셀들은 납이 피복된 일정 길이의 도체 리본들에 의해 연결된다.On the other hand, a unit solar cell including a solar cell electrode formed as described above has a small electromotive force, so a plurality of unit solar cell cells are connected to form and use a solar cell module (Photovoltaic Module) having an appropriate electromotive force. At this time, each unit solar cell is connected by conductor ribbons of a certain length coated with lead.
또한 본 발명에 따른 도전성 페이스트는 결정질 태양전지(P-type, N-type), PESC(Passivated Emitter Solar Cell), PERC(Passivated Emitter and Rear Cell), PERL(Passivated Emitter Real Locally Diffused) 등의 구조 및 더블 프린팅(Double printing), 듀얼 프린팅(Dual printing) 등 변경된 인쇄 공정에도 모두 적용이 가능하다.Also, the conductive paste according to the present invention includes structures such as crystalline solar cells (P-type, N-type), PESC (Passivated Emitter Solar Cell), PERC (Passivated Emitter and Rear Cell), and PERL (Passivated Emitter Real Locally Diffused), and It can be applied to all of the changed printing processes such as double printing and dual printing.
제조예Manufacturing example
(1) 제조예 1(1) Production Example 1
옥타데실아민(octadecylamine; ODA)을 에탄올에 용해시켜 제조한 0.1% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 옥타데실아민으로 코팅 처리된 유리 프릿을 수득하였다. After adding a glass frit of Pb-Te-Bi type to an organic solution of 0.1% concentration prepared by dissolving octadecylamine (ODA) in ethanol, the ball mill was performed at 80 rpm for 24 hours at room temperature. After that, drying was performed in an oven at 50° C. for 1 hour to obtain a glass frit coated with octadecylamine.
(2) 제조예 2(2) Production Example 2
상기 제조예 1에서, 스테아릭산(stearic acid)을 에탄올에 용해시켜 0.3% 농도의 유기 용액을 제조한 것을 제외하고는 상기 제조예 1과 동일한 방법으로 스테아릭산으로 코팅 처리된 유리 프릿을 수득하였다.In Preparation Example 1, a glass frit coated with stearic acid was obtained in the same manner as in Preparation Example 1, except that stearic acid was dissolved in ethanol to prepare an organic solution having a concentration of 0.3%.
(3) 제조예 3(3) Production Example 3
옥타데실아민(octadecylamine; ODA)을 에탄올에 용해시켜 제조한 0.1% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 옥타데실아민으로 1차 코팅 처리된 유리 프릿을 수득하였다. After adding a glass frit of Pb-Te-Bi type to an organic solution of 0.1% concentration prepared by dissolving octadecylamine (ODA) in ethanol, the ball mill was performed at 80 rpm for 24 hours at room temperature. , After this, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit primarily coated with octadecylamine.
옥타데실아민(octadecylamine; ODA)을 에탄올에 용해시켜 제조한 0.1% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 옥타데실아민으로 2차 코팅 처리된 유리 프릿을 수득하였다. After adding a glass frit of Pb-Te-Bi type to an organic solution of 0.1% concentration prepared by dissolving octadecylamine (ODA) in ethanol, the ball mill was performed at 80 rpm for 24 hours at room temperature. , After this, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit secondary coated with octadecylamine.
(4) 제조예 4(4) Production Example 4
옥타데실아민(octadecylamine; ODA)을 에탄올에 용해시켜 제조한 0.1% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 옥타데실아민으로 1차 코팅 처리된 유리 프릿을 수득하였다. After adding a glass frit of Pb-Te-Bi type to an organic solution of 0.1% concentration prepared by dissolving octadecylamine (ODA) in ethanol, the ball mill was performed at 80 rpm for 24 hours at room temperature. , After this, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit primarily coated with octadecylamine.
스테아릭산(stearic acid)을 에탄올에 용해시켜 제조한 0.3% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 스테아릭산으로 2차 코팅 처리된 유리 프릿을 수득하였다. After adding Pb-Te-Bi type glass frit to the 0.3% concentration organic solution prepared by dissolving stearic acid in ethanol, the ball mill proceeded at 80 rpm for 24 hours at room temperature. Then, drying was performed in an oven at 50° C. for 1 hour to obtain a glass frit secondary coated with stearic acid.
(5) 제조예 5(5) Production Example 5
스테아릭산(stearic acid)을 에탄올에 용해시켜 제조한 0.3% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 스테아릭산으로 1차 코팅 처리된 유리 프릿을 수득하였다. After adding Pb-Te-Bi type glass frit to the 0.3% concentration organic solution prepared by dissolving stearic acid in ethanol, the ball mill proceeded at 80 rpm for 24 hours at room temperature. Thereafter, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit primarily coated with stearic acid.
옥타데실아민(octadecylamine; ODA)을 에탄올에 용해시켜 제조한 0.1% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 옥타데실아민으로 2차 코팅 처리된 유리 프릿을 수득하였다. After adding a glass frit of Pb-Te-Bi type to an organic solution of 0.1% concentration prepared by dissolving octadecylamine (ODA) in ethanol, the ball mill was performed at 80 rpm for 24 hours at room temperature. , After this, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit secondary coated with octadecylamine.
(6) 제조예 6(6) Production Example 6
스테아릭산(stearic acid)을 에탄올에 용해시켜 제조한 0.3% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 스테아릭산으로 1차 코팅 처리된 유리 프릿을 수득하였다. After adding Pb-Te-Bi type glass frit to the 0.3% concentration organic solution prepared by dissolving stearic acid in ethanol, the ball mill proceeded at 80 rpm for 24 hours at room temperature. Thereafter, a drying operation was performed in an oven at 50° C. for 1 hour to obtain a glass frit primarily coated with stearic acid.
스테아릭산(stearic acid)을 에탄올에 용해시켜 제조한 0.3% 농도의 유기 용액에 Pb-Te-Bi 타입의 유리 프릿을 첨가한 후 상온에서 볼 밀(Ball-mill) 80rpm으로 24시간 진행되었다, 이 후 50℃의 오븐(oven)에서 1시간 동안 건조 작업을 수행하여 스테아릭산으로 2차 코팅 처리된 유리 프릿을 수득하였다. After adding Pb-Te-Bi type glass frit to the 0.3% concentration organic solution prepared by dissolving stearic acid in ethanol, the ball mill proceeded at 80 rpm for 24 hours at room temperature. Then, drying was performed in an oven at 50° C. for 1 hour to obtain a glass frit secondary coated with stearic acid.
실시예 및 비교예Examples and comparative examples
하기 표 1에 나타낸 바와 같은 조성(예컨대, 중량%)으로, 코팅 처리된 유리 프릿, 유기 바인더, 용매 및 분산제를 넣고 혼합믹서를 사용하여 분산한 후, 실버 파우더(구상, 평균 입경 1㎛)를 혼합하고 또한 삼본밀을 사용하여 분산하였다. 그 뒤 감압 탈포하고 도전성 페이스트를 제조하였다. 실시예 1 내지 6은 각각 제조예 1 내지 제조예 6에 따라 수득된 유리 프릿을 사용하였고, 비교예 1은 코팅 처리되지 않은 Pb-Te-Bi 타입의 유리 프릿을 사용하였다.To the composition as shown in Table 1 (for example, by weight), coated glass frit, an organic binder, a solvent and a dispersant are added and dispersed using a mixing mixer, and then silver powder (spherical, average particle diameter 1 μm) The mixture was also dispersed using a sambon mill. Then, degassing under reduced pressure was carried out to prepare a conductive paste. Examples 1 to 6 used the glass frit obtained according to Preparation Examples 1 to 6, respectively, and Comparative Example 1 used a glass frit of Pb-Te-Bi type not coated.
구분division 실시예 1Example 1 실시예 2Example 2 실시예 3Example 3 실시예 4Example 4 실시예 5Example 5 실시예 6Example 6 비교예 1Comparative Example 1
실버 파우더 Silver powder 8888 8888 8888 8888 8888 8888 8888
바인더bookbinder 0.40.4 0.40.4 0.40.4 0.40.4 0.40.4 0.40.4 0.40.4
용매(texanol)Solvent (texanol) 66 66 66 66 66 66 66
분산제Dispersant 3.63.6 3.63.6 3.63.6 3.63.6 3.63.6 3.63.6 3.63.6
유리 프릿Glass frit 제조예 1Preparation Example 1 22
제조예 2Preparation Example 2 22
제조예 3Preparation Example 3 22
제조예 4Preparation Example 4 22
제조예 5Preparation Example 5 22
제조예 6Preparation Example 6 22
무코팅No coating 22
실험예 (1) 유리 프릿의 코팅성 평가 Experimental Example (1) Evaluation of coating properties of glass frit
상기 제조예 1 내지 6에 따라 제조된 표면 코팅 유리 프릿들과 무코팅 유리 프릿을 물에 넣고 교반 및 방치하여 코팅성을 비교 평가하였다. 코팅성의 비교 평가는 유리 프릿이 첨가된 용액을 교반 후 60min 및 24시간 동안 방치시켜 코팅성을 육안으로 관찰하여 진행하였다. 도 1 내지 3은 유리 프릿의 코팅성을 평가하기 위한 것으로서, 유리 프릿을 물에 넣고 교반한 직후(도 1)와 60분(도 2), 24시간(도 3) 방치시킨 후의 상태를 촬영한 이미지이다. 도 1 내지 3을 참조하면, 지방아민으로 단독 코팅된 유리 프릿(제조예 1)이 가장 빠르게 침전이 발생하고 코팅이 잘되어 소수성이 유지되는 것을 확인할 수 있다. 지방산으로 코팅시 친수성을 가지며 무코팅 유리프릿 대비 분산성을 유지하는 것을 확인할 수 있다. Surface coating glass frits prepared according to Preparation Examples 1 to 6 and uncoated glass frits were added to water, stirred, and left to stand for comparative evaluation of coating properties. The comparative evaluation of coating property was performed by observing the coating property with the naked eye by stirring the solution to which the glass frit was added and leaving it for 60 minutes and 24 hours. 1 to 3 are for evaluating the coating properties of the glass frit, and immediately after stirring the glass frit into water (FIG. 1), and 60 minutes (FIG. 2), 24 hours (FIG. 3), and the state after standing. It is an image. 1 to 3, it can be seen that the glass frit coated exclusively with fatty amine (Preparation Example 1) is the fastest to precipitate and the coating is well maintained to maintain hydrophobicity. It can be seen that it has hydrophilicity when coated with fatty acids and maintains dispersibility compared to uncoated glass frit.
(2) 열중량 분석(Thermogravimetric analysis; TGA)(2) Thermogravimetric analysis (TGA)
상기 제조예 1 내지 6에 따라 제조된 표면 코팅 유리 프릿들과 무코팅 유리 프릿에 대해 열중량분석을 수행하였다. 도 4는 제조예 1 내지 6에 따라 제조된 표면 코팅 유리 프릿들과 무코팅 유리 프릿에 대해 열중량분석을 수행한 결과를 나타낸 것이며, 도 5는 열중량분석 수행 후 촬영 이미지를 나타낸 것이다. 도 4를 참조하면, 코팅제 함량(농도)에 따라 무게 감소폭이 커지는 것이 확인되며, 이를 통해 균일하게 코팅된 것을 알 수 있다. 특히 지방산으로 2차 코팅된 경우(제조예 4, 6) 코팅된 함량이 증가하는 것을 확인할 수 있다. 도 5를 참조하면, 코팅제 함량이 증가함에 따라 glass 표면에 검게 잔탄이 발생한 것을 확인할 수 있으며 이는 코팅이 잘 되었음을 의미한다. Thermogravimetric analysis was performed on the surface coated glass frits and the uncoated glass frits prepared according to Preparation Examples 1 to 6. FIG. 4 shows the results of thermogravimetric analysis on the surface coated glass frits and the uncoated glass frits prepared according to Preparation Examples 1 to 6, and FIG. 5 shows a photographed image after performing thermogravimetric analysis. Referring to FIG. 4, it is confirmed that the weight reduction width is increased according to the content (concentration) of the coating agent, and it can be seen that the coating is uniform. In particular, when the secondary coating with fatty acids (Production Examples 4 and 6), it can be seen that the coated content increases. Referring to FIG. 5, it can be seen that black xanthan occurred on the glass surface as the coating content increased, which means that the coating was well performed.
(3) 부착력 평가 1(3) Evaluation of adhesion 1
상기 실시예 및 비교예에 따라 제조된 도전성 페이스트를 이용하여 상기와 같은 방법으로 태양전지 셀들을 제조한 후, 각 셀들의 전극에 태빙 공정(tabbing process)을 통해 도체 리본(ribbon)을 부착시켰다. 사용된 리본은 60Sn40Pb(kosbon社) 제품이고, 인두기를 이용하여 350℃에서 부착이 진행되었다. 이 후, 태양전지 전극과 리본 사이의 부착력을 측정하였다. 부착력 측정 장비는 LS1(Lloyd社) 제품으로, 180도 방향으로 250mm/min의 속도로 부착력 측정이 진행되었다. 도 6은 실시예 및 비교예에 따라 제조된 도전성 페이스트를 이용하여 제조된 태양전지 전극과 리본 사이의 부착력 측정 결과를 나타낸다. 도 6을 참조하면, 지방아민으로 1차 코팅된 제조예 1,3,4는 분산성이 향상되어 부착력 또한 균일한 것을 알 수 있으며, 지방산으로 1차 코팅된 제조예 2,5,6은 분산성이 저하되어 부착력이 불균일한 것을 알 수 있다. 결론적으로 1차 코팅 종류에 따라 부착력이 결정되는 것을 확인할 수 있고, 지방아민으로 1차 코팅 후 지방산으로 2차 코팅한 경우(제조예 4) 부착력이 가장 우수한 것을 알 수 있다.After manufacturing the solar cells using the conductive paste prepared according to the Examples and Comparative Examples in the same manner as above, a conductor ribbon was attached to the electrodes of each cell through a tabbing process. The ribbon used was a product of 60Sn40Pb (kosbon), and was attached at 350°C using an ironing machine. Thereafter, the adhesion between the solar cell electrode and the ribbon was measured. The adhesive force measuring device is LS1 (Lloyd), and the adhesive force was measured at a speed of 250 mm/min in the 180 degree direction. 6 shows a result of measuring adhesion between a solar cell electrode and a ribbon manufactured using a conductive paste prepared according to Examples and Comparative Examples. Referring to FIG. 6, it can be seen that Preparation Examples 1, 3, and 4 coated with fatty amines have improved dispersibility and uniform adhesion, and Preparation Examples 2, 5, and 6 coated with fatty acids are powdered. It can be seen that the acidity is lowered and the adhesion is uneven. In conclusion, it can be seen that the adhesion is determined according to the primary coating type, and it can be seen that the adhesion is best when the primary coating with fatty amine and secondary coating with fatty acid (Production Example 4).
(4) 부착력 평가 2(4) Evaluation of adhesion 2
상기 실시예 1, 4, 6 및 비교예 1에 따라 제조된 도전성 페이스트를 이용하여 상기와 같은 방법으로 태양전지 셀들을 제조한 후, 각 셀들의 전극에 상술한 태빙 공정(tabbing process)을 통해 도체 리본을 부착시켰다. 이 후, 도체 리본을 탈착하고 계면 이미지들을 측정하였다. 도 7은 도체 리본의 탈착 후 촬영한 전극의 표면 이미지들이다. 도 7을 참조하면, 지방아민으로 1차 코팅 시(실시예 1, 4) 분산성 향상으로 reaching 현상이 덜하고, 이후 지방산으로 추가 코팅 시(실시예 4) Ag 전극 내부에서 뜯어지는 현상으로 즉, Glass와 Si wafer간 부착력 우수한 것을 알 수 있다. 지방산으로만 코팅 시(실시예 6) Ag 전극 전체적으로 reaching이 발생하는 것을 알 수 있다. After manufacturing solar cell cells in the same manner as described above using the conductive pastes prepared according to Examples 1, 4, 6 and Comparative Example 1, the conductors of each cell were subjected to a conductor through the above-described tabbing process. The ribbon was attached. Thereafter, the conductor ribbon was detached and interfacial images were measured. 7 are surface images of an electrode photographed after desorption of a conductor ribbon. Referring to FIG. 7, when the primary coating with fatty amine (Examples 1 and 4) improves dispersibility, the reaching phenomenon is less, and when further coated with fatty acid (Example 4), it is a phenomenon that tears off the Ag electrode. , It can be seen that the adhesion between Glass and Si wafer is excellent. It can be seen that when coating only with fatty acids (Example 6), reaching across the Ag electrode occurs.
(5) 변환효율 및 저항 측정(5) Conversion efficiency and resistance measurement
상기 실시예 1 내지 6 및 비교예 1에 따라 제조된 도전성 페이스트를 wafer의 전면에 40㎛ 메쉬의 스크린 프린팅 기법으로 패턴 인쇄하고, 벨트형 건조로를 사용하여 200~350 ℃에서 20초에서 30초 동안 건조시켰다. 이후 Wafer의 후면에 Al paste를 인쇄한 후 동일한 방법으로 건조하였다. 상기 과정으로 형성된 Cell을 벨트형 소성로를 사용하여 500 내지 900 ℃사이로 20초에서 30초간 소성을 행하여 태양전지 Cell을 제작하였다.The conductive pastes prepared according to Examples 1 to 6 and Comparative Example 1 were pattern printed on the front surface of the wafer by a screen printing technique of 40 μm mesh, and using a belt-type drying furnace at 200 to 350° C. for 20 to 30 seconds. It was dried. After that, Al paste was printed on the back side of the wafer and dried in the same way. Cells formed in the above process were calcined for 20 to 30 seconds between 500 and 900°C using a belt-type calcination furnace to produce a solar cell.
상기 제조된 Cell은 태양전지 효율측정장비(Halm社, cetisPV-Celltest 3)를 사용하여, 단락전류(Isc), 개방전압(Voc), 변환효율(Eff), 곡선인자(FF), 직렬저항(Rs) 및 선저항(Rline)을 측정하여 하기 표 2에 나타내었다.The manufactured cell uses solar cell efficiency measurement equipment (Halm, cetisPV-Celltest 3), short circuit current (Isc), open voltage (Voc), conversion efficiency (Eff), curve factor (FF), series resistance ( Rs) and line resistance (Rline) are measured and are shown in Table 2 below.
구분division Isc(A)Isc(A) Voc(V)Voc(V) Eff(%)Eff(%) FF(%)FF(%) Rser(Ω)Rser(Ω) Rsht(Ω)Rsht(Ω) Grid 저항(1-2)Grid resistance (1-2) Grid 저항(2-3)Grid resistance (2-3)
비교예 1Comparative Example 1 10.087210.0872 0.66310.6631 22.23822.238 80.51680.516 0.000730.00073 832832 26.826.8 27.027.0
실시예 1Example 1 10.105810.1058 0.66410.6641 22.31122.311 80.55180.551 0.000780.00078 389389 27.227.2 27.827.8
실시예 2Example 2 10.083910.0839 0.66290.6629 22.23022.230 80.54680.546 0.000750.00075 393393 26.726.7 28.528.5
실시예 3Example 3 10.107710.1077 0.66390.6639 22.29722.297 80.58380.583 0.000760.00076 555555 27.427.4 28.428.4
실시예 4Example 4 10.109710.1097 0.66470.6647 22.32322.323 80.58280.582 0.000770.00077 606606 27.827.8 28.128.1
실시예 5Example 5 10.085910.0859 0.66310.6631 22.25022.250 80.57680.576 0.000800.00080 592592 26.826.8 28.728.7
실시예 6Example 6 10.093910.0939 0.66290.6629 22.22922.229 80.45880.458 0.000790.00079 775775 27.327.3 27.827.8
상기 표 2에 나타나는 것과 같이, 지방아민으로 1차 코팅 처리된 유리 프릿을 포함하는 도전성 페이스트(예컨대, 실시예 1, 3, 및 4)로 제조된 전극을 포함하는 태양전지의 경우, 단락전류 및 개방전압 증가로 인하여 효율이 증가한 것을 확인할 수 있다. 가장 우수하게는 1차로 지방아민 코팅 후 2차로 지방산 코팅한 유리 프릿을 사용하는 경우(실시예 4) 태양전지의 발전 효율이 가장 개선된 것을 알 수 있다.As shown in Table 2, in the case of a solar cell including an electrode made of a conductive paste (for example, Examples 1, 3, and 4) including a glass frit primarily coated with fatty amine, short-circuit current and It can be seen that the efficiency increased due to the increase of the open voltage. Most excellently, when a fatty acid coated glass frit is used as a primary fatty acid coating and then a secondary fatty acid coating (Example 4), it can be seen that the power generation efficiency of the solar cell is most improved.
전술한 각 실시예에서 예시된 특징, 구조, 효과 등은 실시예들이 속하는 분야의 통상의 지식을 가지는 자에 의하여 다른 실시예들에 대해서도 조합 또는 변형되어 실시 가능하다. 따라서 이러한 조합과 변형에 관계된 내용들은 본 발명의 범위에 포함되는 것으로 해석되어야 할 것이다.Features, structures, effects, and the like exemplified in each of the above-described embodiments may be combined or modified with respect to other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

Claims (9)

  1. 금속 분말, 유리 프릿, 및 유기 비히클을 포함하되,Metal powder, glass frit, and organic vehicle,
    상기 유리 프릿의 표면은 지방아민 및 지방산으로 코팅 처리된 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The surface of the glass frit is a conductive paste for a solar cell electrode, characterized in that coated with fatty amines and fatty acids.
  2. 제1항에 있어서, According to claim 1,
    상기 유리 프릿은 상기 지방아민 또는 지방산으로 1차 코팅되고, 상기 지방아민 또는 지방산으로 2차 코팅처리된 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The glass frit is a conductive paste for a solar cell electrode, characterized in that the primary coating with the fatty amine or fatty acid, and secondary coating with the fatty amine or fatty acid.
  3. 제1항에 있어서, According to claim 1,
    상기 유리 프릿은 지방아민으로 1차 코팅되고, 지방아민 또는 지방산으로 2차 코팅된 유리 프릿을 사용하는 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The glass frit is a conductive paste for a solar cell electrode, characterized in that a glass frit is first coated with fatty amine and second coated with fatty amine or fatty acid.
  4. 제1항에 있어서, According to claim 1,
    상기 유리 프릿은 지방아민으로 1차 코팅되고, 지방산으로 2차 코팅된 유리 프릿을 사용하는 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The glass frit is a conductive paste for a solar cell electrode, characterized in that the glass frit is first coated with fatty amine and secondary coated with fatty acid.
  5. 제1항에 있어서, According to claim 1,
    상기 지방아민은 탄소수 6 내지 24의 알킬아민계 물질을 포함하는 태양전지 전극용 도전성 페이스트.The fatty amine is a conductive paste for a solar cell electrode comprising an alkylamine-based material having 6 to 24 carbon atoms.
  6. 제1항에 있어서,According to claim 1,
    상기 알킬아민계 물질은 트리에틸아민(Triethylamine), 헵틸아민(Heptylamine), 옥타데실아민(Octadecylamine), 헥사데실아민(Hexadecylamine), 데실아민(Decylamine), 옥틸아민(Octylamine), 디데실아민(Didecylamine) 및 트리옥틸아민(Trioctylamine) 중에서 선택된 적어도 하나를 포함하는 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The alkylamine-based materials include triethylamine, heptylamine, octadecylamine, hexadecylamine, decylamine, octylamine, and didecylamine ) And trioctylamine (Trioctylamine) conductive paste for a solar cell electrode, characterized in that it comprises at least one.
  7. 제1항에 있어서,According to claim 1,
    상기 지방산은 라우르산(Lauric acid), 올레익산(Oleic acid), 스테아릭산(Stearic acid), 팔미트산(Palmitic acid) 및 아세트산(Acetic acid) 중에서 선택된 적어도 하나를 포함하는 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The fatty acid is characterized in that it comprises at least one selected from lauric acid, oleic acid, stearic acid, palmitic acid and acetic acid Conductive paste for battery electrodes.
  8. 제1항에 있어서,According to claim 1,
    상기 유리 프릿은 농도가 0.1 내지 0.3%인 지방아민 또는 지방산이 녹아있는 유기 용매 또는 수용액으로 코팅된 것을 특징으로 하는 태양전지 전극용 도전성 페이스트.The glass frit is a conductive paste for a solar cell electrode, characterized in that it is coated with an organic solvent or an aqueous solution in which fatty amine or fatty acid having a concentration of 0.1 to 0.3% is dissolved.
  9. 기재 상부에 전면 전극을 구비하고, 기재 하부에 배면 전극을 구비한 태양전지에 있어서, In the solar cell having a front electrode on the upper substrate, and a rear electrode on the lower substrate,
    상기 전면 전극은, 제1항의 태양전지 전극용 도전성 페이스트를 도포한 후 건조 및 소성시켜 제조된 것을 특징으로 하는 태양전지.The front electrode is a solar cell, characterized in that produced by drying and firing after applying the conductive paste for a solar cell electrode of claim 1.
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