WO2012147378A1 - Method for forming solar cell collecting electrode, set of conductive compositions for forming solar cell collecting electrode, and solar cell - Google Patents

Method for forming solar cell collecting electrode, set of conductive compositions for forming solar cell collecting electrode, and solar cell Download PDF

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Publication number
WO2012147378A1
WO2012147378A1 PCT/JP2012/051235 JP2012051235W WO2012147378A1 WO 2012147378 A1 WO2012147378 A1 WO 2012147378A1 JP 2012051235 W JP2012051235 W JP 2012051235W WO 2012147378 A1 WO2012147378 A1 WO 2012147378A1
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Prior art keywords
electrode
solar cell
forming
bus bar
conductive
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PCT/JP2012/051235
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French (fr)
Japanese (ja)
Inventor
奈央 佐藤
石川　和憲
一雄 荒川
愛美 金
浩一 上迫
マルワン ダムリン
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横浜ゴム株式会社
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Application filed by 横浜ゴム株式会社 filed Critical 横浜ゴム株式会社
Priority to CN201280003092.8A priority Critical patent/CN103140932B/en
Priority to DE112012001862.1T priority patent/DE112012001862T5/en
Publication of WO2012147378A1 publication Critical patent/WO2012147378A1/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
    • 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
    • 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
    • H01L31/04—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 adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/05—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
    • H01L31/0504—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module
    • 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 method for forming a solar cell collecting electrode, a conductive composition for forming a solar cell collecting electrode, and a solar cell having an electrode formed using these.
  • Solar cells that convert light energy such as sunlight into electrical energy have been actively developed in various structures and configurations as interest in global environmental issues increases.
  • solar cells using a semiconductor substrate such as silicon are most commonly used due to advantages such as conversion efficiency and manufacturing cost.
  • Patent Document 1 discloses that “an organic binder, a solvent, conductive particles, glass frit, a metal oxide, and a temperature of 150 to 800 ° C.
  • Patent Document 2 discloses that “a zinc oxide particle having a specific surface area of 6 m 2 / g or less, which is an electrode paste for a solar cell containing conductive particles, a lead-free glass frit, a resin binder, and zinc oxide particles.
  • the electrode paste for solar cells is contained in an amount of 10% by weight or more based on the total amount of zinc oxide ”([Claim 1]), and it is described that zinc oxide is known as an additive for the electrode paste. ([0005]).
  • Patent Document 3 the present applicant states that “silver powder (A), silver oxide (B), and organic solvent (D) are contained, and the silver powder (A) is contained in the composition.
  • a conductive composition that is 50% by mass or more in a simple substance and a silver compound ” has been proposed ([Claim 1]), and includes an embodiment containing silver carboxylate as an optional component, glass frit, metal additives, and the like. (2) [0030] [0033] [0034] and the like.
  • the present inventor examined the pastes and conductive compositions described in Patent Documents 1 to 3, and found that the solar cell fill factor (FF) obtained by the effect of addition of metal oxide (zinc oxide) and Although the photoelectric conversion efficiency (Eff) is improved, depending on the addition amount of the metal oxide, the solder adhesion to the bus bar electrode (bus electrode) formed in the solar battery cell is inferior, and the interconnector in which the metal ribbon is coated with solder is used. It became clear that it was difficult to modularize the solar battery cells.
  • FF solar cell fill factor
  • Eff photoelectric conversion efficiency
  • the present invention provides a method for forming a solar cell current collecting electrode and a conductive composition for forming a solar cell current collecting electrode that can form an electrode having excellent solder adhesion, and is produced using these. It is an object of the present invention to provide a solar cell excellent in fill factor (FF) and photoelectric conversion efficiency (Eff).
  • FF fill factor
  • Eff photoelectric conversion efficiency
  • the present inventor has formed solder adhesion by forming each of the finger electrode and the bus bar electrode using two kinds of conductive compositions having different metal oxide contents. It was found that an excellent electrode can be formed, and a solar cell excellent in fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced, and the present invention has been completed. That is, the present invention provides the following (1) to (4).
  • An electrode forming method comprising: A finger electrode forming step of forming a finger electrode using a conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A); After the finger electrode forming step, a bus bar electrode is formed by using a bus bar electrode forming conductive composition containing less than 3 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). And a bus bar electrode forming step.
  • a set of conductive compositions for forming a solar cell collecting electrode comprising at least conductive particles (A), glass frit (B) and solvent (C), A conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A); A conductive composition for forming a solar cell collector electrode, comprising: a conductive composition for forming a bus bar electrode containing less than 3 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). set.
  • a solar cell module in which the solar cells described in (3) above are joined in series using an interconnector whose surface is coated with solder.
  • a method of forming a solar cell collector electrode and a conductive composition for forming a solar cell collector electrode capable of forming an electrode excellent in solder adhesion, and these The solar cell excellent in the fill factor (FF) and photoelectric conversion efficiency (Eff) produced using can be provided.
  • FIG. 1 is a schematic cross-sectional view of a solar battery cell.
  • FIG. 2 is a schematic top view as seen from the surface electrode side of the solar battery cell and a schematic bottom view as seen from the back electrode side.
  • FIG. 3 is a schematic perspective view of the solar cell module and an enlarged cross-sectional view of the joint.
  • the set of the conductive composition for forming a solar cell collecting electrode of the present invention includes at least conductive particles (A), glass frit (B) and solvent (C And a finger electrode containing 3 to 10 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive particles (A).
  • a bus bar electrode containing less than 3 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive composition for formation (hereinafter also referred to as “finger electrode composition”) and the conductive particles (A).
  • a conductive composition for forming a solar cell current collecting electrode having a conductive composition for formation (hereinafter, also referred to as “bus bar electrode composition”).
  • Good other components will be described in detail. In addition, it explains in full detail as a component of the set composition of this invention about the component which is common in the said composition for finger electrodes, and the said composition for bus bar electrodes.
  • the conductive particles (A) used in the set composition of the present invention are not particularly limited.
  • a metal material having an electrical resistivity of 20 ⁇ 10 ⁇ 6 ⁇ ⁇ cm or less can be used.
  • Specific examples of the metal material include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), and the like.
  • One species may be used alone, or two or more species may be used in combination.
  • gold, silver, and copper are used because an electrode having a small volume resistivity can be formed and a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced. Is preferred, and silver is more preferred.
  • FF fill factor
  • Eff photoelectric conversion efficiency
  • an average particle diameter means the average value of the particle diameter of a metal powder, and means the 50% volume cumulative diameter (D50) measured using the laser diffraction type particle size distribution measuring apparatus.
  • the particle diameter used as the basis for calculating the average value is an average value obtained by dividing the total value of the major axis and the minor axis by 2, and in the case of a perfect circle, Refers to the diameter.
  • the spherical shape refers to the shape of particles having a major axis / minor axis ratio of 2 or less.
  • the average particle diameter of the conductive particles (A) is preferably 0.7 to 5 ⁇ m because the printability is better, and the sintering speed is appropriate and the workability is improved.
  • the thickness is more preferably 1 to 3 ⁇ m.
  • a commercially available product can be used as the conductive particles (A).
  • Specific examples thereof include AgC-102 (shape: spherical, average particle size: 1.5 ⁇ m, Fukuda Metal Foil Powder Industry).
  • AGC-103 shape: spherical, average particle size: 1.5 ⁇ m, manufactured by Fukuda Metal Foil Powder Co., Ltd.
  • AG4-8F shape: spherical, average particle size: 2.2 ⁇ m, manufactured by DOWA Electronics
  • AG2-1C shape: spherical, average particle size: 1.0 ⁇ m, manufactured by DOWA Electronics
  • AG3-11F shape: spherical, average particle size: 1.4 ⁇ m, manufactured by DOWA Electronics
  • SPN5J shape: spherical
  • EHD shape: spherical, average particle size
  • the glass frit (B) used in the set composition of the present invention is not particularly limited, and it is preferable to use one having a softening temperature of 300 ° C. or higher and a firing temperature (heat treatment temperature) or lower.
  • Specific examples of the glass frit (B) include borosilicate glass frit having a softening temperature of 300 to 800 ° C.
  • the shape of the glass frit (B) is not particularly limited, and may be spherical or crushed powder.
  • the average particle diameter (D50) of the spherical glass frit is preferably 0.1 to 20 ⁇ m, and more preferably 1 to 10 ⁇ m.
  • the content of the glass frit (B) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the conductive particles (A).
  • the solvent (C) used in the set composition of the present invention is not particularly limited as long as it can apply the finger electrode composition and the bus bar electrode composition onto a substrate.
  • Specific examples of the solvent (C) include butyl carbitol, butyl carbitol acetate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, diethylene glycol dibutyl ether, methyl ethyl ketone, isophorone, Examples thereof include ⁇ -terpineol, and these may be used alone or in combination of two or more.
  • the content of the solvent (C) is preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight with respect to 100 parts by weight of the conductive particles (A).
  • the metal oxide (D) used in the set composition of the present invention is not particularly limited as long as it is an oxide formed by bonding oxygen atoms and metal elements directly or indirectly.
  • Specific examples of the metal oxide (D) include, for example, zinc oxide, titanium oxide, silicon oxide, cerium oxide, bismuth oxide, tin oxide, and ABO 3 (wherein A consists of Ba, Ca, and Sr). Represents at least one element selected from the group, and B represents at least one element selected from the group consisting of Ti, Zr and Hf and represents Ti). These may be used alone or in combination of two or more.
  • the average particle diameter of the metal oxide (D) can form an electrode with a small volume resistivity, and has a better fill factor (FF) and photoelectric conversion efficiency (Eff). Is preferably 10 ⁇ m or less.
  • the average particle diameter means an average value of the particle diameter of the metal oxide, and all the metals existing at a viewing angle of 1 mm 2 using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the particle diameter of the oxide can be measured and calculated from the average value. Moreover, it can also calculate using the specific surface area calculated
  • an electrode having a smaller volume resistivity can be formed with an average particle diameter of the metal oxide (D), and a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) is produced.
  • D metal oxide
  • FF fill factor
  • Eff photoelectric conversion efficiency
  • it is preferably 10 nm or more and less than 100 nm, more preferably 30 to 50 nm, except for zinc oxide having aluminum or gallium described later.
  • the said metal oxide (D) can form an electrode with small volume resistivity, and produces a photovoltaic cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff).
  • FF fill factor
  • Eff photoelectric conversion efficiency
  • it is preferably conductive zinc oxide (hereinafter, referred to as “conductive zinc oxide”) partially containing aluminum or gallium (hereinafter, abbreviated as “aluminum or the like” in this paragraph).
  • conductive zinc oxide partially containing aluminum or gallium
  • having aluminum or the like partially means a state in which zinc oxide is doped with aluminum or the like, and can be formed by mixing an oxide such as aluminum with zinc oxide and baking.
  • the average particle diameter of the said conductive zinc oxide can form an electrode with smaller volume resistivity, and can produce a photovoltaic cell with still more favorable fill factor (FF) and photoelectric conversion efficiency (Eff) Therefore, the thickness is preferably 0.02 to 10 ⁇ m, and more preferably 0.02 to 3.5 ⁇ m.
  • the said metal oxide (D) can form an electrode with small volume resistivity, and produces a photovoltaic cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff).
  • the perovskite is preferable for the reason that it can be used.
  • Specific examples of the perovskite include perovskites represented by BaTiO 3 , SrTiO 3 , CaTiO 3 and BrZrO 3 , and among them, SrTiO 3 is more preferable.
  • the content of the metal oxide (D) in the finger electrode composition is 3 to 10 parts by mass with respect to 100 parts by mass of the conductive particles (A).
  • the content of the metal oxide (D) in the bus bar electrode composition is less than 3 parts by mass with respect to 100 parts by mass of the conductive particles (A).
  • the metal oxide (D) is an optional component.
  • the metal oxide (D) contributes to a reduction in volume resistivity while adversely affecting the solder adhesion. That is, when a solar battery cell is modularized, a bus bar electrode that comes into contact with an interconnector coated with solder is formed by using the bus bar electrode composition having a low content of the metal oxide (D), so that the solder adhesion is achieved. It is considered that the low volume resistivity could be secured by forming the finger electrode using the finger electrode composition having a high content of the metal oxide (D).
  • the content of the metal oxide (D) in the finger electrode composition is because a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced.
  • the amount is preferably 5 to 10 parts by mass, more preferably 5 to 8 parts by mass with respect to 100 parts by mass of the conductive particles (A).
  • the content of the metal oxide (D) in the bus bar electrode composition is such that the conductive particles (A) 100 can be formed because an electrode (bus bar electrode) superior in solder adhesion can be formed.
  • the amount is preferably 0 to 2 parts by mass, more preferably 0 to 1 part by mass with respect to parts by mass.
  • the set composition of the present invention can form an electrode with a small volume resistivity, and can produce a solar cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff). It is preferable that the composition contains a fatty acid silver salt (E).
  • the fatty acid silver salt (E) is not particularly limited as long as it is a silver salt of an organic carboxylic acid (fatty acid), and is described, for example, in paragraphs [0063] to [0068] of JP-A-2008-198595.
  • JP 2010-92684 A Fatty acid silver salts having one or more hydroxyl groups, secondary fatty acid silver salts described in paragraphs [0046] to [0056] of the same publication, and [0022] to [0026] of JP 2011-35062 A
  • a silver carboxylate or the like can be used.
  • carbon has excellent printability, can form an electrode with a smaller volume resistivity, and can produce a solar cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff).
  • a polycarboxylic acid silver salt (E3) having 3 or more carboxy silver bases (—COOAg) without having a hydroxyl group (—OH) is used because an electrode having a smaller volume resistivity can be formed. Is particularly preferred.
  • examples of the fatty acid silver salt (E2) include compounds represented by any one of the following formulas (I) to (III).
  • n represents an integer of 0 to 2
  • R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms
  • R 2 represents an alkylene group having 1 to 6 carbon atoms.
  • the plurality of R 2 may be the same or different
  • the plurality of R 1 may be the same or different.
  • R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms
  • a plurality of R 1 may be the same or different.
  • R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms
  • R 3 represents an alkylene group having 1 to 6 carbon atoms.
  • the plurality of R 1 may be the same or different.
  • Examples of the polycarboxylic acid silver salt (E3) include a compound represented by the following formula (IV).
  • m represents an integer of 2 to 6
  • R 4 represents an m-valent saturated aliphatic hydrocarbon group having 1 to 24 carbon atoms
  • an m-valent unsaturated fat having 2 to 12 carbon atoms.
  • fatty acid silver salt (E1) examples include 2-methylpropanoic acid silver salt (also known as isobutyric acid silver salt) and 2-methylbutanoic acid silver salt.
  • fatty acid silver salt (E2) examples include 2-hydroxyisobutyric acid silver salt and 2,2-bis (hydroxymethyl) -n-butyric acid silver salt.
  • polycarboxylic acid silver salt (E3) examples include 1,3,5-pentanetricarboxylic acid silver salt and 1,2,3,4-butanetetracarboxylic acid silver salt. Is done.
  • the content when the fatty acid silver salt (E) is contained, the content is 0.1 to 10 with respect to 100 parts by mass of the conductive particles (A) because the printing property is better.
  • the amount is preferably part by mass, more preferably 1 to 10 parts by mass.
  • the set composition of this invention may contain the resin binder as needed from a printable viewpoint.
  • the resin binder is obtained by dissolving a resin having a binder function in a solvent.
  • Specific examples of the resin include ethyl cellulose resin, nitrocellulose resin, alkyd resin, acrylic resin, styrene resin, phenol resin and the like, and these may be used alone or in combination of two or more. May be. Among these, it is preferable to use ethyl cellulose resin from the viewpoint of thermal decomposability.
  • the solvent examples include ⁇ -terpineol, butyl carbitol, butyl carbitol acetate, diacetone alcohol, methyl isobutyl ketone, and the like. You may use the above together.
  • the solvent may be a part of the solvent (C) described above.
  • the set composition of this invention may contain additives, such as a reducing agent, as needed.
  • a reducing agent include ethylene glycols.
  • the content of silver oxide is preferably 5 parts by mass or less with respect to 100 parts by mass of the solvent (C) described above, because the thixotropy becomes better and the aspect ratio can be further increased. It is more preferable that the amount is less than or equal to parts, and an embodiment that does not substantially contain silver oxide is most preferable.
  • the method for producing the set composition of the present invention that is, the method for preparing the finger electrode composition and the bus bar electrode composition is not particularly limited, and the conductive particles (A), the glass frit (B), The solvent (C), the metal oxide (D), and the fatty acid silver salt (E) which may be optionally contained, the resin binder and additives are mixed by a roll, a kneader, an extruder, a universal agitator, etc. The method of doing is mentioned.
  • the solar cell collector electrode forming method of the present invention is a solar cell collector electrode forming method for forming a solar cell collector electrode, wherein the composition for finger electrodes is described above.
  • a solar cell current collecting electrode comprising: a finger electrode forming step for forming a finger electrode using an object; and a bus bar electrode forming step for forming a bus bar electrode using the bus bar electrode composition after the finger electrode forming step. It is a forming method. Below, a finger electrode formation process and a bus-bar electrode formation process are explained in full detail.
  • the finger electrode formation process which the electrode formation method of this invention has is a process of forming a finger electrode using the said composition for finger electrodes.
  • a finger electrode forming step for example, a wiring forming step of forming the wiring (finger electrode precursor) by applying the composition for finger electrodes on a silicon substrate (an antireflection film when an antireflection film is provided). And a method including a heat treatment step of forming a finger electrode by heat-treating (firing) the obtained wiring.
  • the antireflection film can be formed by a known method such as a plasma CVD method.
  • the wiring is fired through the antireflection film during the heat treatment in the heat treatment step so that the electrode contacts the silicon substrate. Can be formed.
  • a wiring formation process and a heat treatment process are explained in full detail.
  • the said wiring formation process is a process of apply
  • specific examples of the coating method include inkjet, screen printing, gravure printing, offset printing, letterpress printing, and the like.
  • the finger electrode composition is applied.
  • the object may be applied not only to the part that forms the finger electrode, but also to the part that forms the bus bar electrode.
  • the heat treatment step is a step of obtaining finger electrodes by heat-treating the wiring obtained in the wiring formation step.
  • the heat treatment is not particularly limited, but it is preferably a heat treatment (baking) at a temperature of 150 to 860 ° C. for several seconds to several tens of minutes.
  • the temperature and time are within this range, even when an antireflection film is formed on the silicon substrate, the electrode can be easily formed by the fire-through method.
  • the heat treatment step may be performed by irradiation with ultraviolet rays or infrared rays.
  • the bus bar electrode forming step of the electrode forming method of the present invention is a step of forming a bus bar electrode using the bus bar electrode composition.
  • a method including a heat treatment step of forming a bus bar electrode by heat-treating (firing) the obtained wiring is basically the same as the steps described in the finger electrode formation step.
  • the solar cell of the present invention comprises a surface electrode on the light-receiving surface side, a semiconductor substrate and a back electrode, and at least the surface electrode uses the set composition of the present invention described above, and the electrode forming method of the present invention described above. It is a solar battery cell formed using.
  • the solar battery cell of the present invention can be applied to the formation of the back electrode of the all back electrode type (so-called back contact type) solar cell, the above-described set composition of the present invention can be applied to the all back electrode type. This can also be applied to solar cells.
  • the solar cell of the present invention will be described by taking a crystalline silicon solar cell as an example.
  • the present invention is not limited to this.
  • a solar cell 10 of the present invention includes a surface electrode 1 (finger electrode 1a) on the light receiving surface side, a pn junction silicon substrate 4 in which an n layer 3 and a p layer 5 are joined (hereinafter referred to as these). In addition, it is also referred to as “crystalline silicon substrate 7”) and a back electrode 6 (full surface electrode 6a).
  • FIG. 1 is a schematic cross-sectional view taken along the line II of FIG.
  • the photovoltaic cell 10 of this invention comprises the anti-reflective film 2 in which the pyramid-like texture was formed for the reflectance reduction.
  • the solar battery cell 10 of the present invention includes a finger electrode 1a and a bus bar electrode 1b as the surface electrode 1 on the light receiving surface side. Moreover, as shown in FIG. 2B and FIG. 1, the solar battery cell 10 of the present invention includes a full-surface electrode 6 a and a connecting portion 6 b as the back electrode 6.
  • the surface electrode and / or back electrode which the photovoltaic cell of this invention comprises is at least the surface electrode formed using the set composition of this invention, arrangement
  • positioning (pitch), shape, height, width of an electrode Etc. are not particularly limited.
  • positioning (pitch), shape, height, width of an electrode Etc. are not particularly limited.
  • the surface electrode 1 having the finger electrodes 1a and the bus bar electrodes 1b is formed using the set composition of the present invention.
  • the back electrode 6 may be formed using the set composition of the present invention, but it is preferable to form the entire surface electrode 6a with an aluminum electrode and the connecting portion 6b with a silver electrode.
  • the antireflection film that the solar battery cell of the present invention may have is a film (film thickness: about 0.05 to 0.1 ⁇ m) formed on a portion of the light receiving surface where the surface electrode is not formed.
  • a film film thickness: about 0.05 to 0.1 ⁇ m
  • the crystalline silicon substrate included in the solar battery cell of the present invention is not particularly limited, and a known silicon substrate (plate thickness: about 100 to 450 ⁇ m) for forming a solar battery can be used. Any polycrystalline silicon substrate may be used.
  • the crystalline silicon substrate has a pn junction, which means that a second conductivity type light-receiving surface impurity diffusion region is formed on the surface side of the first conductivity type semiconductor substrate.
  • the second conductivity type is p-type.
  • the impurity imparting p-type include boron and aluminum
  • examples of the impurity imparting n-type include phosphorus and arsenic.
  • the solar cell module of the present invention is a solar cell module in which the solar cells of the present invention are joined in series using an interconnector whose surface is coated with solder. Below, the structure of the solar cell module of this invention is demonstrated using FIG.
  • the solar cell module 20 of the present invention is obtained by joining solar cells 10 in series using an interconnector 8 in which the surface of a metal ribbon 8b is covered with solder 8a.
  • solder 8a copper or aluminum ribbon coated with a conductive adhesive can be suitably used as the metal ribbon.
  • the bus bar electrode 1b of the front surface electrode 1 and the solder 8a of the interconnector 8 are in close contact with each other, and the connecting portion 6b of the back electrode 6 and the solder of the interconnector 8 are in contact with each other. 8a is in close contact.
  • the bus bar electrode (and the connection portion of the back electrode) is formed using the above-mentioned bus bar electrode composition, the adhesion with the solder of the interconnector is good, and it is easily modularized. can do.
  • a conductive composition for finger electrodes was prepared by adding conductive particles shown in Table 1 below to the ball mill so as to have the composition ratio shown in Table 1 and mixing them.
  • Silver powder AgC-103 (shape: spherical, average particle size: 1.5 ⁇ m, manufactured by Fukuda Metal Foil Powder Industry)
  • Solvent ⁇ -terpineol Zinc oxide: ZnO (average particle size 20-40 nm, manufactured by Teica)
  • -Bismuth oxide Bi 2 O 3 (average particle size 51 nm, manufactured by CI Kasei Co., Ltd.)
  • Conductive zinc oxide: ZnO: Al average particle size: 3.5 ⁇ m, manufactured by Honjo Chemical Co., Ltd.
  • Resin binder EC-100FTP (ethyl cellulose resin solid content: 9%, manufactured by Nisshin Kasei Co., Ltd.)
  • Glass frit lead borosilicate glass powder
  • bus bar electrode compositions B1 to B4 To the ball mill, conductive particles shown in Table 2 below were added so as to have the composition ratio shown in Table 2 below, and these were mixed to prepare a conductive composition for a bus bar electrode.
  • each component in the following 2nd table used the same thing as the said 1st table
  • Examples 1-7 Comparative Examples 1-2
  • a silicon substrate single crystal silicon wafer, LS-25TVA, 156 mm ⁇ 156 mm ⁇ 200 ⁇ m, manufactured by Shin-Etsu Chemical Co., Ltd.
  • an aluminum paste was applied to the entire back surface by screen printing and dried.
  • a predetermined wiring pattern of finger electrodes and a predetermined wiring pattern of bus bar electrodes are formed on the surface of the silicon substrate by applying the prepared conductive compositions by screen printing according to the combinations shown in Table 3 below. did.
  • a sample of a solar battery cell in which conductive wiring (finger electrodes and bus bar electrodes) was formed by baking for 60 seconds in a baking furnace at a peak temperature of 740 ° C. was produced.
  • solder adhesion> A solder ribbon (composition: Sn-3Ag-0.5Cu) was mounted on the bus bar electrode of the solar cell sample produced using a soldering iron. Thereafter, according to JIS K6850: 1999, a tensile shear test was performed at a tensile speed of 50 mm / min, and the load at break (MPa) was measured. The results are shown in Table 3 below. Here, when the load at the time of breakage is 15 MPa or more, it can be evaluated that it has solder adhesion necessary for modularization of the solar battery cell.

Abstract

The purpose of the present invention is to provide a method for forming a solar cell collecting electrode whereby an electrode having excellent solder cohesion can be formed. This method for forming a solar cell collecting electrode is a method for forming a solar cell collecting electrode in which a conductive composition for forming a solar cell collecting electrode, including at least conductive particles (A), glass frit (B), and a solvent (C), is used to form a solar cell collecting electrode, wherein the method for forming a solar cell collecting electrode has a finger electrode formation step in which a conductive composition for forming a finger electrode containing a metal oxide (D) in a proportion of 3-10 mass parts to 100 mass parts of the conductive particles (A) is used to form a finger electrode; and a bus bar electrode formation step subsequent to the finger electrode formation step, in which a conductive composition for forming a bus bar electrode containing a metal oxide (D) in a proportion of less than 3 mass parts to 100 mass parts of the conductive particles (A) is used to form a bus bar electrode.

Description

太陽電池集電電極形成方法、太陽電池集電電極形成用導電性組成物のセットおよび太陽電池セルSOLAR CELL COLLECTING ELECTRODE FORMING METHOD, SOLAR BATTERY COLLECTING ELECTRODE CONDUCTIVE COMPOSITION SET, AND SOLAR CELL
　本発明は、太陽電池集電電極形成方法、太陽電池集電電極形成用導電性組成物およびこれらを用いて形成した電極を有する太陽電池セルに関する。 The present invention relates to a method for forming a solar cell collecting electrode, a conductive composition for forming a solar cell collecting electrode, and a solar cell having an electrode formed using these.
　太陽光のような光エネルギーを電気エネルギーに変換する太陽電池は、地球環境問題に対する関心が高まるにつれ、積極的に種々の構造・構成のものが開発されている。その中でも、シリコンなどの半導体基板を用いた太陽電池は、その変換効率、製造コストなどの優位性により最も一般的に用いられている。 Solar cells that convert light energy such as sunlight into electrical energy have been actively developed in various structures and configurations as interest in global environmental issues increases. Among them, solar cells using a semiconductor substrate such as silicon are most commonly used due to advantages such as conversion efficiency and manufacturing cost.
　このような太陽電池の電極を形成する材料としては、例えば、特許文献１には、「有機バインダと、溶剤と、導電性粒子と、ガラスフリットと、金属酸化物と、１５０～８００℃の温度範囲で気体に変化する物質とを含む、太陽電池電極用導電性ペースト。」が記載されており（［請求項１］）、上記金属酸化物として酸化亜鉛等が記載されており（［請求項２］）、上記気体に変化する物質として有機金属化合物が記載されている（［請求項３］［請求項４］）。 As a material for forming such an electrode of a solar cell, for example, Patent Document 1 discloses that “an organic binder, a solvent, conductive particles, glass frit, a metal oxide, and a temperature of 150 to 800 ° C. A conductive paste for solar cell electrodes containing a substance that changes to a gas in a range ”([Claim 1]), and zinc oxide or the like as the metal oxide ([Claim 2]), an organometallic compound is described as the substance that changes into the gas ([Claim 3] and [Claim 4]).
　更に、特許文献２には、「導電性粒子、無鉛ガラスフリット、樹脂バインダー、および酸化亜鉛粒子を含む太陽電池用電極ペーストであって、比表面積が６ｍ2／ｇ以下である酸化亜鉛粒子が、酸化亜鉛の総量に対して１０重量％以上含まれる、太陽電池用電極ペースト。」が記載されており（［請求項１］）、電極ペーストの添加剤として酸化亜鉛が公知である旨が記載されている（［０００５］）。 Furthermore, Patent Document 2 discloses that “a zinc oxide particle having a specific surface area of 6 m 2 / g or less, which is an electrode paste for a solar cell containing conductive particles, a lead-free glass frit, a resin binder, and zinc oxide particles. The electrode paste for solar cells is contained in an amount of 10% by weight or more based on the total amount of zinc oxide ”([Claim 1]), and it is described that zinc oxide is known as an additive for the electrode paste. ([0005]).
　一方、特許文献３には、本出願人により、「銀粉（Ａ）と、酸化銀（Ｂ）と、有機溶媒（Ｄ）とを含有し、該銀粉（Ａ）が組成物に含有される銀単体および銀化合物中５０質量％以上である導電性組成物」が提案されており（［請求項１］）、任意成分としてカルボン酸銀を含む態様や、ガラスフリット、金属系添加剤等の他の添加剤を含む態様が記載されている（［請求項２］［００３０］［００３３］［００３４］等）。 On the other hand, in Patent Document 3, the present applicant states that “silver powder (A), silver oxide (B), and organic solvent (D) are contained, and the silver powder (A) is contained in the composition. A conductive composition that is 50% by mass or more in a simple substance and a silver compound ”has been proposed ([Claim 1]), and includes an embodiment containing silver carboxylate as an optional component, glass frit, metal additives, and the like. (2) [0030] [0033] [0034] and the like.
特開２００７－２９４６７７号公報JP 2007-294677 A 特表２０１１－５０１４４４号公報Special table 2011-501444 gazette 特開２０１１－３５０６２号公報JP 2011-35062 A
　しかしながら、本発明者が、特許文献１～３に記載されたペーストや導電性組成物について検討したところ、金属酸化物（酸化亜鉛）の添加効果によって得られる太陽電池セルの曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）は向上するものの、金属酸化物の添加量によっては、太陽電池セルに形成されるバスバー電極（バス電極）に対する半田密着性が劣り、金属リボンを半田で被覆したインターコネクタを用いて太陽電池セルをモジュール化することが困難であることが明らかとなった。 However, the present inventor examined the pastes and conductive compositions described in Patent Documents 1 to 3, and found that the solar cell fill factor (FF) obtained by the effect of addition of metal oxide (zinc oxide) and Although the photoelectric conversion efficiency (Eff) is improved, depending on the addition amount of the metal oxide, the solder adhesion to the bus bar electrode (bus electrode) formed in the solar battery cell is inferior, and the interconnector in which the metal ribbon is coated with solder is used. It became clear that it was difficult to modularize the solar battery cells.
　そこで、本発明は、半田密着性に優れた電極を形成することができる太陽電池集電電極形成方法および太陽電池集電電極形成用導電性組成物のセット、ならびに、これらを用いて作製される曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）に優れた太陽電池セルを提供することを課題とする。 Therefore, the present invention provides a method for forming a solar cell current collecting electrode and a conductive composition for forming a solar cell current collecting electrode that can form an electrode having excellent solder adhesion, and is produced using these. It is an object of the present invention to provide a solar cell excellent in fill factor (FF) and photoelectric conversion efficiency (Eff).
　本発明者は、上記課題を解決するため鋭意検討した結果、フィンガー電極およびバスバー電極の各々を金属酸化物の含有量が異なる２種の導電性組成物を用いて形成することにより、半田密着性に優れた電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）に優れた太陽電池セルを作製できることを見出し、本発明を完成させた。即ち、本発明は、下記（１）～（４）を提供する。 As a result of intensive studies to solve the above-mentioned problems, the present inventor has formed solder adhesion by forming each of the finger electrode and the bus bar electrode using two kinds of conductive compositions having different metal oxide contents. It was found that an excellent electrode can be formed, and a solar cell excellent in fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced, and the present invention has been completed. That is, the present invention provides the following (1) to (4).
　（１）少なくとも導電性粒子（Ａ）、ガラスフリット（Ｂ）および溶媒（Ｃ）を含有する太陽電池集電電極形成用導電性組成物を用いて太陽電池集電電極を形成する太陽電池集電電極形成方法であって、
　上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３～１０質量部含有するフィンガー電極形成用導電性組成物を用いてフィンガー電極を形成するフィンガー電極形成工程と、
　上記フィンガー電極形成工程の後に、上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３質量部未満含有するバスバー電極形成用導電性組成物を用いてバスバー電極を形成するバスバー電極形成工程と、を有する太陽電池集電電極形成方法。 (1) Solar cell current collector for forming a solar cell current collector electrode using a conductive composition for forming a solar cell current collector electrode containing at least conductive particles (A), glass frit (B) and solvent (C) An electrode forming method comprising:
A finger electrode forming step of forming a finger electrode using a conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A);
After the finger electrode forming step, a bus bar electrode is formed by using a bus bar electrode forming conductive composition containing less than 3 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). And a bus bar electrode forming step.
　（２）少なくとも導電性粒子（Ａ）、ガラスフリット（Ｂ）および溶媒（Ｃ）を含有する太陽電池集電電極形成用導電性組成物のセットであって、
　上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３～１０質量部含有するフィンガー電極形成用導電性組成物と、
　上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３質量部未満含有するバスバー電極形成用導電性組成物と、を有する太陽電池集電電極形成用導電性組成物のセット。 (2) A set of conductive compositions for forming a solar cell collecting electrode, comprising at least conductive particles (A), glass frit (B) and solvent (C),
A conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A);
A conductive composition for forming a solar cell collector electrode, comprising: a conductive composition for forming a bus bar electrode containing less than 3 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). set.
　（３）受光面側の表面電極、半導体基板および裏面電極を具備し、
　少なくとも上記表面電極が、上記（２）に記載の太陽電池集電電極形成用導電性組成物のセットを使用し、上記（１）に記載の太陽電池集電電極形成方法を用いて形成される太陽電池セル。 (3) It comprises a surface electrode on the light receiving surface side, a semiconductor substrate and a back electrode,
At least the surface electrode is formed using the set of the conductive composition for forming a solar cell collector electrode described in (2) above and using the method for forming a solar cell collector electrode described in (1) above. Solar cell.
　（４）表面が半田で被覆されたインターコネクタを用いて上記（３）に記載の太陽電池セルを直列に接合した太陽電池モジュール。 (4) A solar cell module in which the solar cells described in (3) above are joined in series using an interconnector whose surface is coated with solder.
　以下に示すように、本発明によれば、半田密着性に優れた電極を形成することができる太陽電池集電電極形成方法および太陽電池集電電極形成用導電性組成物のセット、ならびに、これらを用いて作製される曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）に優れた太陽電池セルを提供することができる。 As shown below, according to the present invention, a method of forming a solar cell collector electrode and a conductive composition for forming a solar cell collector electrode capable of forming an electrode excellent in solder adhesion, and these The solar cell excellent in the fill factor (FF) and photoelectric conversion efficiency (Eff) produced using can be provided.
図１は太陽電池セルの模式断面図である。FIG. 1 is a schematic cross-sectional view of a solar battery cell. 図２は太陽電池セルの表面電極側からみた模式上面図および裏面電極側からみた模式下面図である。FIG. 2 is a schematic top view as seen from the surface electrode side of the solar battery cell and a schematic bottom view as seen from the back electrode side. 図３は太陽電池モジュールの模式斜視図および接合部の拡大断面図である。FIG. 3 is a schematic perspective view of the solar cell module and an enlarged cross-sectional view of the joint.
 〔太陽電池集電電極形成用導電性組成物のセット〕
　本発明の太陽電池集電電極形成用導電性組成物のセット（以下、「本発明のセット組成物」と略す。）は、少なくとも導電性粒子（Ａ）、ガラスフリット（Ｂ）および溶媒（Ｃ）を含有する太陽電池集電電極形成用導電性組成物のセットであって、上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３～１０質量部含有するフィンガー電極形成用導電性組成物（以下、「フィンガー電極用組成物」ともいう。）と、上記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３質量部未満含有するバスバー電極形成用導電性組成物（以下、「バスバー電極用組成物」ともいう。）と、を有する太陽電池集電電極形成用の導電性組成物のセットである。
　以下に、上記フィンガー電極用組成物および上記バスバー電極用組成物が含有する導電性粒子（Ａ）、ガラスフリット（Ｂ）、溶媒（Ｃ）および金属酸化物（Ｄ）ならびに所望により含有してもよい他の成分等について詳述する。なお、上記フィンガー電極用組成物および上記バスバー電極用組成物で共通する成分については、本発明のセット組成物の成分として詳述する。 [Set of conductive composition for forming solar cell collector electrode]
The set of the conductive composition for forming a solar cell collecting electrode of the present invention (hereinafter abbreviated as “the set composition of the present invention”) includes at least conductive particles (A), glass frit (B) and solvent (C And a finger electrode containing 3 to 10 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). A bus bar electrode containing less than 3 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive composition for formation (hereinafter also referred to as “finger electrode composition”) and the conductive particles (A). A conductive composition for forming a solar cell current collecting electrode having a conductive composition for formation (hereinafter, also referred to as “bus bar electrode composition”).
The conductive electrode (A), the glass frit (B), the solvent (C) and the metal oxide (D) contained in the composition for finger electrodes and the composition for busbar electrodes, and optionally contained below. Good other components will be described in detail. In addition, it explains in full detail as a component of the set composition of this invention about the component which is common in the said composition for finger electrodes, and the said composition for bus bar electrodes.
　＜導電性粒子（Ａ）＞
　本発明のセット組成物で用いる導電性粒子（Ａ）は特に限定されず、例えば、電気抵抗率が２０×１０-6Ω・ｃｍ以下の金属材料を用いることができる。
　上記金属材料としては、具体的には、例えば、金（Ａｕ）、銀（Ａｇ）、銅（Ｃｕ）、アルミニウム（Ａｌ）、マグネシウム（Ｍｇ）、ニッケル（Ｎｉ）等が挙げられ、これらを１種単独で用いてもよく、２種以上を併用してもよい。
　これらのうち、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、金、銀、銅であるのが好ましく、銀であるのがより好ましい。 <Conductive particles (A)>
The conductive particles (A) used in the set composition of the present invention are not particularly limited. For example, a metal material having an electrical resistivity of 20 × 10 −6 Ω · cm or less can be used.
Specific examples of the metal material include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), and the like. One species may be used alone, or two or more species may be used in combination.
Among these, gold, silver, and copper are used because an electrode having a small volume resistivity can be formed and a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced. Is preferred, and silver is more preferred.
　本発明においては、上記導電性粒子（Ａ）は、印刷性が良好となる理由から、平均粒子径が０．５～１０μｍの金属粉末を用いるのが好ましい。
　上記金属粉末のうち、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、球状の銀粉末を用いるのがより好ましい。
　ここで、平均粒子径とは、金属粉末の粒子径の平均値をいい、レーザー回折式粒度分布測定装置を用いて測定された５０％体積累積径（Ｄ５０）をいう。なお、平均値を算出する基になる粒子径は、金属粉末の断面が楕円形である場合はその長径と短径の合計値を２で割った平均値をいい、正円形である場合はその直径をいう。
　また、球状とは、長径／短径の比率が２以下の粒子の形状をいう。 In the present invention, it is preferable to use a metal powder having an average particle diameter of 0.5 to 10 μm for the conductive particles (A) because of good printability.
Among the metal powders, spherical silver powder is used because an electrode having a small volume resistivity can be formed and a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced. Is more preferable.
Here, an average particle diameter means the average value of the particle diameter of a metal powder, and means the 50% volume cumulative diameter (D50) measured using the laser diffraction type particle size distribution measuring apparatus. In addition, when the cross-section of the metal powder is an ellipse, the particle diameter used as the basis for calculating the average value is an average value obtained by dividing the total value of the major axis and the minor axis by 2, and in the case of a perfect circle, Refers to the diameter.
The spherical shape refers to the shape of particles having a major axis / minor axis ratio of 2 or less.
　また、本発明においては、上記導電性粒子（Ａ）の平均粒子径は、印刷性がより良好となる理由から、０．７～５μｍであるのが好ましく、焼結速度が適当となり作業性に優れる理由から、１～３μｍであるのがより好ましい。 In the present invention, the average particle diameter of the conductive particles (A) is preferably 0.7 to 5 μm because the printability is better, and the sintering speed is appropriate and the workability is improved. For excellent reasons, the thickness is more preferably 1 to 3 μm.
　更に、本発明においては、上記導電性粒子（Ａ）として市販品を用いることができ、その具体例としては、ＡｇＣ－１０２（形状：球状、平均粒子径：１．５μｍ、福田金属箔粉工業社製）、ＡｇＣ－１０３（形状：球状、平均粒子径：１．５μｍ、福田金属箔粉工業社製）、ＡＧ４－８Ｆ（形状：球状、平均粒子径：２．２μｍ、ＤＯＷＡエレクトロニクス社製）、ＡＧ２－１Ｃ（形状：球状、平均粒子径：１．０μｍ、ＤＯＷＡエレクトロニクス社製）、ＡＧ３－１１Ｆ（形状：球状、平均粒子径：１．４μｍ、ＤＯＷＡエレクトロニクス社製）、ＳＰＮ５Ｊ（形状：球状、平均粒子径：１．２μｍ、三井金属社製）、ＥＨＤ（形状：球状、平均粒子径：０．５μｍ、三井金属社製）、ＡｇＣ－２０１１（形状：フレーク状、平均粒子径：２～１０μｍ、福田金属箔粉工業社製）、ＡｇＣ－３０１Ｋ（形状：フレーク状、平均粒子径：３～１０μｍ、福田金属箔粉工業社製）等が挙げられる。 Furthermore, in the present invention, a commercially available product can be used as the conductive particles (A). Specific examples thereof include AgC-102 (shape: spherical, average particle size: 1.5 μm, Fukuda Metal Foil Powder Industry). AGC-103 (shape: spherical, average particle size: 1.5 μm, manufactured by Fukuda Metal Foil Powder Co., Ltd.), AG4-8F (shape: spherical, average particle size: 2.2 μm, manufactured by DOWA Electronics) AG2-1C (shape: spherical, average particle size: 1.0 μm, manufactured by DOWA Electronics), AG3-11F (shape: spherical, average particle size: 1.4 μm, manufactured by DOWA Electronics), SPN5J (shape: spherical) , Average particle size: 1.2 μm, manufactured by Mitsui Kinzoku Co., Ltd.), EHD (shape: spherical, average particle size: 0.5 μm, manufactured by Mitsui Kinzoku Co., Ltd.), AgC-2011 (shape: flake shape, average particle size: ~ 10 [mu] m, manufactured by Fukuda Metal Foil & Powder Co., Ltd.), AgC-301K (shape: flaky, average particle size: 3 ~ 10 [mu] m, Fukuda metal foil Powder Co., Ltd.) and the like.
　＜ガラスフリット（Ｂ）＞
　本発明のセット組成物で用いるガラスフリット（Ｂ）は特に限定されず、軟化温度が３００℃以上で、焼成温度（熱処理温度）以下のものを用いるのが好ましい。
　上記ガラスフリット（Ｂ）としては、具体的には、例えば、軟化温度３００～８００℃のホウケイ酸ガラスフリット等が挙げられる。
　上記ガラスフリット（Ｂ）の形状は特に限定されず、球状でも破砕粉状でもよい。球状のガラスフリットの平均粒子径（Ｄ５０）は、０．１～２０μｍであることが好ましく、１～１０μｍであることがより好ましい。さらに、１５μｍ以上の粒子を除去した、シャープな粒度分布を持つガラスフリットを用いることが好ましい。
　上記ガラスフリット（Ｂ）の含有量は、上記導電性粒子（Ａ）１００質量部に対して０．１～１０質量部であるのが好ましく、１～５質量部であるのがより好ましい。 <Glass frit (B)>
The glass frit (B) used in the set composition of the present invention is not particularly limited, and it is preferable to use one having a softening temperature of 300 ° C. or higher and a firing temperature (heat treatment temperature) or lower.
Specific examples of the glass frit (B) include borosilicate glass frit having a softening temperature of 300 to 800 ° C.
The shape of the glass frit (B) is not particularly limited, and may be spherical or crushed powder. The average particle diameter (D50) of the spherical glass frit is preferably 0.1 to 20 μm, and more preferably 1 to 10 μm. Furthermore, it is preferable to use a glass frit having a sharp particle size distribution from which particles of 15 μm or more are removed.
The content of the glass frit (B) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the conductive particles (A).
　＜溶媒（Ｃ）＞
　本発明のセット組成物で用いる溶媒（Ｃ）は、上記フィンガー電極用組成物および上記バスバー電極用組成物を基材上に塗布することができるものであれば特に限定されない。
　上記溶媒（Ｃ）としては、具体的には、例えば、ブチルカルビトール、ブチルカルビトールアセテート、２，２，４－トリメチル－１，３－ペンタンジオールジイソブチレート、ジエチレングリコールジブチルエーテル、メチルエチルケトン、イソホロン、α－テルピネオール等が挙げられ、これらを１種単独で用いても２種以上を併用してもよい。
　また、上記溶媒（Ｃ）の含有量は、上記導電性粒子（Ａ）１００質量部に対して、２～２０質量部であるのが好ましく、５～１５重量部であるのがより好ましい。 <Solvent (C)>
The solvent (C) used in the set composition of the present invention is not particularly limited as long as it can apply the finger electrode composition and the bus bar electrode composition onto a substrate.
Specific examples of the solvent (C) include butyl carbitol, butyl carbitol acetate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, diethylene glycol dibutyl ether, methyl ethyl ketone, isophorone, Examples thereof include α-terpineol, and these may be used alone or in combination of two or more.
Further, the content of the solvent (C) is preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight with respect to 100 parts by weight of the conductive particles (A).
　＜金属酸化物（Ｄ）＞
　本発明のセット組成物で用いる金属酸化物（Ｄ）は、酸素原子と金属元素とが直接または間接に結合して形成された酸化物であれば特に限定されない。
　上記金属酸化物（Ｄ）としては、具体的には、例えば、酸化亜鉛、酸化チタン、酸化ケイ素、酸化セリウム、酸化ビスマス、酸化スズ、ＡＢＯ3（式中、ＡはＢａ、ＣａおよびＳｒからなる群から選択される少なくとも１種の元素を表し、ＢはＴｉ、ＺｒおよびＨｆからなる群から選択される少なくとも１種の元素であってＴｉを含むものを表す。）で表されるペロブスカイト等が挙げられ、これらを１種単独で用いてもよく、２種以上を併用してもよい。 <Metal oxide (D)>
The metal oxide (D) used in the set composition of the present invention is not particularly limited as long as it is an oxide formed by bonding oxygen atoms and metal elements directly or indirectly.
Specific examples of the metal oxide (D) include, for example, zinc oxide, titanium oxide, silicon oxide, cerium oxide, bismuth oxide, tin oxide, and ABO 3 (wherein A consists of Ba, Ca, and Sr). Represents at least one element selected from the group, and B represents at least one element selected from the group consisting of Ti, Zr and Hf and represents Ti). These may be used alone or in combination of two or more.
　本発明においては、上記金属酸化物（Ｄ）の平均粒子径は、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、１０μｍ以下であるのが好ましい。
　ここで、平均粒子径とは、金属酸化物の粒子径の平均値をいい、走査型電子顕微鏡（ＳＥＭ）または透過型電子顕微鏡（ＴＥＭ）を用いて１ｍｍ2の視野角に存在する全ての金属酸化物の粒子径を測定し、その平均値から算出することができる。また、ＢＥＴ法から求めた比表面積と下記式（式中、Ｓは金属酸化物の比表面積を表し、ρは金属酸化物の密度を表す）を用いて算出することもできる。
　平均粒子径＝６／（ρ×Ｓ）
　また、上記金属酸化物（Ｄ）の平均粒子径は、体積抵抗率のより小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）が更に良好な太陽電池セルを作製できる理由から、後述するアルミニウムまたはガリウムを有する酸化亜鉛を除き、１０ｎｍ以上１００ｎｍ未満であるのが好ましく、３０～５０ｎｍであるのがより好ましい。 In the present invention, the average particle diameter of the metal oxide (D) can form an electrode with a small volume resistivity, and has a better fill factor (FF) and photoelectric conversion efficiency (Eff). Is preferably 10 μm or less.
Here, the average particle diameter means an average value of the particle diameter of the metal oxide, and all the metals existing at a viewing angle of 1 mm 2 using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The particle diameter of the oxide can be measured and calculated from the average value. Moreover, it can also calculate using the specific surface area calculated | required from BET method and a following formula (In formula, S represents the specific surface area of a metal oxide, and (rho) represents the density of a metal oxide).
Average particle size = 6 / (ρ × S)
In addition, an electrode having a smaller volume resistivity can be formed with an average particle diameter of the metal oxide (D), and a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) is produced. For reasons that can be achieved, it is preferably 10 nm or more and less than 100 nm, more preferably 30 to 50 nm, except for zinc oxide having aluminum or gallium described later.
　また、本発明においては、上記金属酸化物（Ｄ）は、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、アルミニウムまたはガリウム（以下、本段落においては「アルミニウム等」と略す。）を一部に有する導電性の酸化亜鉛（以下、「導電性酸化亜鉛」という。）であるのが好ましい。
　ここで、アルミニウム等を一部に有するとは、酸化亜鉛がアルミニウム等によりドープされた状態をいい、酸化亜鉛に対してアルミニウム等の酸化物を混合し、焼成することにより形成することができる。
　また、上記導電性酸化亜鉛の平均粒子径は、体積抵抗率のより小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）が更に良好な太陽電池セルを作製できる理由から、０．０２～１０μｍであるのが好ましく、０．０２～３．５μｍであるのがより好ましい。 Moreover, in this invention, the said metal oxide (D) can form an electrode with small volume resistivity, and produces a photovoltaic cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff). For the reason that it can be used, it is preferably conductive zinc oxide (hereinafter, referred to as “conductive zinc oxide”) partially containing aluminum or gallium (hereinafter, abbreviated as “aluminum or the like” in this paragraph).
Here, having aluminum or the like partially means a state in which zinc oxide is doped with aluminum or the like, and can be formed by mixing an oxide such as aluminum with zinc oxide and baking.
Moreover, the average particle diameter of the said conductive zinc oxide can form an electrode with smaller volume resistivity, and can produce a photovoltaic cell with still more favorable fill factor (FF) and photoelectric conversion efficiency (Eff) Therefore, the thickness is preferably 0.02 to 10 μm, and more preferably 0.02 to 3.5 μm.
　更に、本発明においては、上記金属酸化物（Ｄ）は、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、上記ペロブスカイトであるのが好ましい。
　上記ペロブスカイトとしては、具体的には、ＢａＴｉＯ3、ＳｒＴｉＯ3、ＣａＴｉＯ3、ＢｒＺｒＯ3で表されるペロブスカイトが好適に例示され、中でも、ＳｒＴｉＯ3であるのがより好ましい。 Furthermore, in this invention, the said metal oxide (D) can form an electrode with small volume resistivity, and produces a photovoltaic cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff). The perovskite is preferable for the reason that it can be used.
Specific examples of the perovskite include perovskites represented by BaTiO 3 , SrTiO 3 , CaTiO 3 and BrZrO 3 , and among them, SrTiO 3 is more preferable.
　本発明においては、上記フィンガー電極用組成物における上記金属酸化物（Ｄ）の含有量は、上記導電性粒子（Ａ）１００質量部に対して３～１０質量部である。
　同様に、上記バスバー電極用組成物における上記金属酸化物（Ｄ）の含有量は、上記導電性粒子（Ａ）１００質量部に対して３質量部未満である。なお、バスバー電極形成用導電性組成物においては、上記金属酸化物（Ｄ）は任意成分である。
　上記金属酸化物（Ｄ）の含有量が上記範囲であると、半田密着性に優れた電極（バスバー電極）を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）が良好な太陽電池セルを作製することができる。
　これは、詳細には明らかではないが、本発明者らは上記金属酸化物（Ｄ）が体積抵抗率の低減に寄与する一方で、半田密着性に悪い影響を与えるためであると考えている。すなわち、太陽電池セルをモジュール化する際に半田で被覆されたインターコネクタと接触するバスバー電極を上記金属酸化物（Ｄ）の含有量の少ないバスバー電極用組成物を用いて形成することにより半田密着性を確保し、かつ、フィンガー電極を上記金属酸化物（Ｄ）の含有量の多いフィンガー電極用組成物を用いて形成することにより低い体積抵抗率を確保できたためと考えられる。 In the present invention, the content of the metal oxide (D) in the finger electrode composition is 3 to 10 parts by mass with respect to 100 parts by mass of the conductive particles (A).
Similarly, the content of the metal oxide (D) in the bus bar electrode composition is less than 3 parts by mass with respect to 100 parts by mass of the conductive particles (A). In the conductive composition for forming a bus bar electrode, the metal oxide (D) is an optional component.
When the content of the metal oxide (D) is in the above range, an electrode (bus bar electrode) excellent in solder adhesion can be formed, and the fill factor (FF) and photoelectric conversion efficiency (Eff) are good. A solar battery cell can be produced.
Although this is not clear in detail, the present inventors believe that the metal oxide (D) contributes to a reduction in volume resistivity while adversely affecting the solder adhesion. . That is, when a solar battery cell is modularized, a bus bar electrode that comes into contact with an interconnector coated with solder is formed by using the bus bar electrode composition having a low content of the metal oxide (D), so that the solder adhesion is achieved. It is considered that the low volume resistivity could be secured by forming the finger electrode using the finger electrode composition having a high content of the metal oxide (D).
　また、本発明においては、上記フィンガー電極用組成物における上記金属酸化物（Ｄ）の含有量は、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、上記導電性粒子（Ａ）１００質量部に対して５～１０質量部であるのが好ましく、５～８質量部であるのがより好ましい。
　同様に、上記バスバー電極用組成物における上記金属酸化物（Ｄ）の含有量は、半田密着性により優れた電極（バスバー電極）を形成することができる理由から、上記導電性粒子（Ａ）１００質量部に対して０～２質量部であるのが好ましく、０～１質量部であるのがより好ましい。 In the present invention, the content of the metal oxide (D) in the finger electrode composition is because a solar cell having a better fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced. The amount is preferably 5 to 10 parts by mass, more preferably 5 to 8 parts by mass with respect to 100 parts by mass of the conductive particles (A).
Similarly, the content of the metal oxide (D) in the bus bar electrode composition is such that the conductive particles (A) 100 can be formed because an electrode (bus bar electrode) superior in solder adhesion can be formed. The amount is preferably 0 to 2 parts by mass, more preferably 0 to 1 part by mass with respect to parts by mass.
　＜脂肪酸銀塩（Ｅ）＞
　本発明のセット組成物は、体積抵抗率の小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）がより良好な太陽電池セルを作製できる理由から、上記フィンガー電極用組成物が脂肪酸銀塩（Ｅ）を含有しているのが好ましい。
　ここで、上記脂肪酸銀塩（Ｅ）は、有機カルボン酸（脂肪酸）の銀塩であれば特に限定されず、例えば、特開２００８－１９８５９５号公報の［００６３］～［００６８］段落に記載された脂肪酸金属塩（特に３級脂肪酸銀塩）、特許第４４８２９３０号公報の［００３０］段落に記載された脂肪酸銀塩、特開２０１０－９２６８４号公報の［００２９］～［００４５］段落に記載された水酸基を１個以上有する脂肪酸銀塩、同公報の［００４６］～［００５６］段落に記載された２級脂肪酸銀塩、特開２０１１－３５０６２号公報の［００２２］～［００２６］に記載されたカルボン酸銀等を用いることができる。
　これらのうち、印刷性が良好となり、体積抵抗率のより小さい電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）が更に良好な太陽電池セルを作製できる理由から、炭素数１８以下の脂肪酸銀塩（Ｅ１）、カルボキシ銀塩基（－ＣＯＯＡｇ）と水酸基（－ＯＨ）とをそれぞれ１個以上有する脂肪酸銀塩（Ｅ２）、および、水酸基（－ＯＨ）を有さずにカルボキシ銀塩基（－ＣＯＯＡｇ）を２個以上有するポリカルボン酸銀塩（Ｅ３）からなる群から選択される少なくとも１種の脂肪酸銀塩を用いるのが好ましい。
　中でも、体積抵抗率の更に小さい電極を形成することができる理由から、水酸基（－ＯＨ）を有さずにカルボキシ銀塩基（－ＣＯＯＡｇ）を３個以上有するポリカルボン酸銀塩（Ｅ３）を用いるのが特に好ましい。 <Fatty acid silver salt (E)>
The set composition of the present invention can form an electrode with a small volume resistivity, and can produce a solar cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff). It is preferable that the composition contains a fatty acid silver salt (E).
Here, the fatty acid silver salt (E) is not particularly limited as long as it is a silver salt of an organic carboxylic acid (fatty acid), and is described, for example, in paragraphs [0063] to [0068] of JP-A-2008-198595. Fatty acid metal salts (particularly tertiary fatty acid silver salts), fatty acid silver salts described in paragraph [0030] of Japanese Patent No. 4482930, and [0029] to [0045] paragraphs of JP 2010-92684 A Fatty acid silver salts having one or more hydroxyl groups, secondary fatty acid silver salts described in paragraphs [0046] to [0056] of the same publication, and [0022] to [0026] of JP 2011-35062 A A silver carboxylate or the like can be used.
Among these, carbon has excellent printability, can form an electrode with a smaller volume resistivity, and can produce a solar cell with a better fill factor (FF) and photoelectric conversion efficiency (Eff). A fatty acid silver salt (E1) having a number of 18 or less, a fatty acid silver salt (E2) having at least one carboxy silver base (—COOAg) and a hydroxyl group (—OH), and no hydroxyl group (—OH) It is preferable to use at least one fatty acid silver salt selected from the group consisting of silver salt of polycarboxylic acid (E3) having two or more carboxy silver bases (—COOAg).
Among them, a polycarboxylic acid silver salt (E3) having 3 or more carboxy silver bases (—COOAg) without having a hydroxyl group (—OH) is used because an electrode having a smaller volume resistivity can be formed. Is particularly preferred.
　ここで、上記脂肪酸銀塩（Ｅ２）としては、例えば、下記式（Ｉ）～（ＩＩＩ）のいずれかで表される化合物が挙げられる。
Figure JPOXMLDOC01-appb-C000001
（式（Ｉ）中、ｎは０～２の整数を表し、Ｒ1は水素原子または炭素数１～１０のアルキル基を表し、Ｒ2は炭素数１～６のアルキレン基を表す。ｎが０または１である場合、複数のＲ2はそれぞれ同一であっても異なっていてもよい。ｎが２である場合、複数のＲ1はそれぞれ同一であっても異なっていてもよい。
　式（ＩＩ）中、Ｒ1は水素原子または炭素数１～１０のアルキル基を表し、複数のＲ1はそれぞれ同一であっても異なっていてもよい。
　式（ＩＩＩ）中、Ｒ1は水素原子または炭素数１～１０のアルキル基を表し、Ｒ3は炭素数１～６のアルキレン基を表す。複数のＲ1はそれぞれ同一であっても異なっていてもよい。） Here, examples of the fatty acid silver salt (E2) include compounds represented by any one of the following formulas (I) to (III).
Figure JPOXMLDOC01-appb-C000001
(In the formula (I), n represents an integer of 0 to 2, R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkylene group having 1 to 6 carbon atoms. When it is 0 or 1, the plurality of R 2 may be the same or different, and when n is 2, the plurality of R 1 may be the same or different.
In the formula (II), R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and a plurality of R 1 may be the same or different.
In the formula (III), R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 3 represents an alkylene group having 1 to 6 carbon atoms. The plurality of R 1 may be the same or different. )
　また、上記ポリカルボン酸銀塩（Ｅ３）としては、例えば、下記式（ＩＶ）で表される化合物であるが挙げられる。
Figure JPOXMLDOC01-appb-C000002
（式（ＩＶ）中、ｍは、２～６の整数を表し、Ｒ4は、炭素数１～２４のｍ価の飽和脂肪族炭化水素基、炭素数２～１２のｍ価の不飽和脂肪族炭化水素基、炭素数３～１２のｍ価の脂環式炭化水素基、または、炭素数６～１２のｍ価の芳香族炭化水素基を表す。Ｒ4の炭素数をｐとすると、ｍ≦２ｐ＋２である。） Examples of the polycarboxylic acid silver salt (E3) include a compound represented by the following formula (IV).
Figure JPOXMLDOC01-appb-C000002
(In the formula (IV), m represents an integer of 2 to 6, R 4 represents an m-valent saturated aliphatic hydrocarbon group having 1 to 24 carbon atoms, and an m-valent unsaturated fat having 2 to 12 carbon atoms. Represents an aromatic hydrocarbon group, an m-valent alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an m-valent aromatic hydrocarbon group having 6 to 12 carbon atoms, where the carbon number of R 4 is p. m ≦ 2p + 2.)
　上記脂肪酸銀塩（Ｅ１）としては、具体的には、２－メチルプロパン酸銀塩（別名：イソ酪酸銀塩）、２－メチルブタン酸銀塩等が好適に例示される。
　また、上記脂肪酸銀塩（Ｅ２）としては、具体的には、２－ヒドロキシイソ酪酸銀塩、２，２－ビス（ヒドロキシメチル）－ｎ－酪酸銀塩等が好適に例示される。
　また、上記ポリカルボン酸銀塩（Ｅ３）としては、具体的には、１，３，５－ペンタントリカルボン酸銀塩、１，２，３，４－ブタンテトラカルボン酸銀塩等が好適に例示される。 Specific examples of the fatty acid silver salt (E1) include 2-methylpropanoic acid silver salt (also known as isobutyric acid silver salt) and 2-methylbutanoic acid silver salt.
Specific examples of the fatty acid silver salt (E2) include 2-hydroxyisobutyric acid silver salt and 2,2-bis (hydroxymethyl) -n-butyric acid silver salt.
Specific examples of the polycarboxylic acid silver salt (E3) include 1,3,5-pentanetricarboxylic acid silver salt and 1,2,3,4-butanetetracarboxylic acid silver salt. Is done.
　本発明においては、上記脂肪酸銀塩（Ｅ）を含有する場合の含有量は、印刷性がより良好となる理由から、上記導電性粒子（Ａ）１００質量部に対して、０．１～１０質量部であるのが好ましく、１～１０質量部であるのがより好ましい。 In the present invention, when the fatty acid silver salt (E) is contained, the content is 0.1 to 10 with respect to 100 parts by mass of the conductive particles (A) because the printing property is better. The amount is preferably part by mass, more preferably 1 to 10 parts by mass.
　＜樹脂バインダー＞
　本発明のセット組成物は、印刷性の観点から、必要に応じて樹脂バインダーを含有していてもよい。
　上記樹脂バインダーは、バインダー機能を有する樹脂を溶媒に溶解したものである。
　上記樹脂としては、具体的には、例えば、エチルセルロース樹脂、ニトロセルロース樹脂、アルキド樹脂、アクリル樹脂、スチレン樹脂、フェノール樹脂等が挙げられ、これらを１種単独で用いても２種以上を併用してもよい。これらのうち、熱分解性の観点から、エチルセルロース樹脂を用いるのが好ましい。
　また、上記溶媒としては、具体的には、例えば、α－テルピネオール、ブチルカルビトール、ブチルカルビトールアセテート、ジアセトンアルコール、メチルイソブチルケトン等が挙げられ、これらを１種単独で用いても２種以上を併用してもよい。なお、本発明においては、上記溶媒は、上述した溶媒（Ｃ）の一部であってもよい。 <Resin binder>
The set composition of this invention may contain the resin binder as needed from a printable viewpoint.
The resin binder is obtained by dissolving a resin having a binder function in a solvent.
Specific examples of the resin include ethyl cellulose resin, nitrocellulose resin, alkyd resin, acrylic resin, styrene resin, phenol resin and the like, and these may be used alone or in combination of two or more. May be. Among these, it is preferable to use ethyl cellulose resin from the viewpoint of thermal decomposability.
Specific examples of the solvent include α-terpineol, butyl carbitol, butyl carbitol acetate, diacetone alcohol, methyl isobutyl ketone, and the like. You may use the above together. In the present invention, the solvent may be a part of the solvent (C) described above.
　本発明のセット組成物は、必要に応じて、還元剤等の添加剤を含有していてもよい。
　上記還元剤としては、具体的には、例えば、エチレングリコール類等が挙げられる。
　一方、チクソ性がより良好となり、アスペクト比をより高くすることができる理由から酸化銀の含有量は上述した溶媒（Ｃ）１００質量部に対して５質量部以下であるのが好ましく、１質量部以下であるのがより好ましく、実質的に酸化銀を含有していない態様が最も好ましい。 The set composition of this invention may contain additives, such as a reducing agent, as needed.
Specific examples of the reducing agent include ethylene glycols.
On the other hand, the content of silver oxide is preferably 5 parts by mass or less with respect to 100 parts by mass of the solvent (C) described above, because the thixotropy becomes better and the aspect ratio can be further increased. It is more preferable that the amount is less than or equal to parts, and an embodiment that does not substantially contain silver oxide is most preferable.
　本発明のセット組成物の製造方法、すなわち、上記フィンガー電極用組成物および上記バスバー電極用組成物の調製方法は特に限定されず、それぞれ、上記導電性粒子（Ａ）、ガラスフリット（Ｂ）、上記溶媒（Ｃ）および上記金属酸化物（Ｄ）ならびに所望により含有していてもよい上記脂肪酸銀塩（Ｅ）、樹脂バインダーおよび添加剤を、ロール、ニーダー、押出し機、万能かくはん機等により混合する方法が挙げられる。 The method for producing the set composition of the present invention, that is, the method for preparing the finger electrode composition and the bus bar electrode composition is not particularly limited, and the conductive particles (A), the glass frit (B), The solvent (C), the metal oxide (D), and the fatty acid silver salt (E) which may be optionally contained, the resin binder and additives are mixed by a roll, a kneader, an extruder, a universal agitator, etc. The method of doing is mentioned.
 〔太陽電池集電電極形成方法〕
　本発明の太陽電池集電電極形成方法（以下、「本発明の電極形成方法」という。）は、太陽電池集電電極を形成する太陽電池集電電極形成方法であって、上記フィンガー電極用組成物を用いてフィンガー電極を形成するフィンガー電極形成工程と、上記フィンガー電極形成工程の後に、上記バスバー電極用組成物を用いてバスバー電極を形成するバスバー電極形成工程と、を有する太陽電池集電電極形成方法である。
　以下に、フィンガー電極形成工程およびバスバー電極形成工程について詳述する。 [Method for forming solar cell collecting electrode]
The solar cell collector electrode forming method of the present invention (hereinafter referred to as “the electrode forming method of the present invention”) is a solar cell collector electrode forming method for forming a solar cell collector electrode, wherein the composition for finger electrodes is described above. A solar cell current collecting electrode comprising: a finger electrode forming step for forming a finger electrode using an object; and a bus bar electrode forming step for forming a bus bar electrode using the bus bar electrode composition after the finger electrode forming step. It is a forming method.
Below, a finger electrode formation process and a bus-bar electrode formation process are explained in full detail.
　＜フィンガー電極形成工程＞
　本発明の電極形成方法が有するフィンガー電極形成工程は、上記フィンガー電極用組成物を用いてフィンガー電極を形成する工程である。
　上記フィンガー電極形成工程としては、例えば、上記フィンガー電極用組成物をシリコン基板（反射防止膜を具備する場合は反射防止膜）上に塗布して配線（フィンガー電極前駆体）を形成する配線形成工程と、得られた配線を熱処理（焼成）してフィンガー電極を形成する熱処理工程とを有する方法等が挙げられる。
　また、反射防止膜は、プラズマＣＶＤ法等の公知の方法により形成することができる。
　なお、本発明の太陽電池セルが反射防止膜を具備する場合、上記配線が上記熱処理工程における熱処理の際に上記反射防止膜をファイヤースルーすることにより、上記電極がシリコン基板上に接触するように形成することができる。
　以下に、配線形成工程、熱処理工程について詳述する。 <Finger electrode formation process>
The finger electrode formation process which the electrode formation method of this invention has is a process of forming a finger electrode using the said composition for finger electrodes.
As the finger electrode forming step, for example, a wiring forming step of forming the wiring (finger electrode precursor) by applying the composition for finger electrodes on a silicon substrate (an antireflection film when an antireflection film is provided). And a method including a heat treatment step of forming a finger electrode by heat-treating (firing) the obtained wiring.
The antireflection film can be formed by a known method such as a plasma CVD method.
In addition, when the solar cell of the present invention includes an antireflection film, the wiring is fired through the antireflection film during the heat treatment in the heat treatment step so that the electrode contacts the silicon substrate. Can be formed.
Below, a wiring formation process and a heat treatment process are explained in full detail.
　（配線形成工程）
　上記配線形成工程は、上記フィンガー電極用組成物をシリコン基板（反射防止層を具備する場合は反射防止膜）上に塗布して配線（フィンガー電極前駆体）を形成する工程である。
　ここで、塗布方法としては、具体的には、例えば、インクジェット、スクリーン印刷、グラビア印刷、オフセット印刷、凸版印刷等が挙げられる。
　なお、本発明においては、後述するバスバー電極形成工程においてバスバー電極を形成する部分に上記バスバー電極用組成物を塗布することから、その前工程である上記配線形成工程においては、上記フィンガー電極用組成物は、フィンガー電極を形成する部分だけでなく、バスバー電極を形成する部分にも塗布されていてもよい。 (Wiring formation process)
The said wiring formation process is a process of apply | coating the said composition for finger electrodes on a silicon substrate (An antireflection film in the case of providing an antireflection layer), and forming wiring (finger electrode precursor).
Here, specific examples of the coating method include inkjet, screen printing, gravure printing, offset printing, letterpress printing, and the like.
In the present invention, since the bus bar electrode composition is applied to a portion where the bus bar electrode is formed in the bus bar electrode forming step, which will be described later, in the wiring forming step, which is the previous step, the finger electrode composition is applied. The object may be applied not only to the part that forms the finger electrode, but also to the part that forms the bus bar electrode.
　（熱処理工程）
　上記熱処理工程は、上記配線形成工程で得られた配線を熱処理してフィンガー電極を得る工程である。
　本発明においては、上記熱処理は特に限定されないが、１５０～８６０℃の温度で、数秒～数十分間、加熱（焼成）する処理であるのが好ましい。温度および時間がこの範囲であると、シリコン基板上に反射防止膜を形成した場合であっても、ファイヤースルー法により容易に電極を形成することができる。
　また、上記配線形成工程で得られた配線は、紫外線または赤外線の照射でも電極を形成することができるため、上記熱処理工程は、紫外線または赤外線の照射によるものであってもよい。 (Heat treatment process)
The heat treatment step is a step of obtaining finger electrodes by heat-treating the wiring obtained in the wiring formation step.
In the present invention, the heat treatment is not particularly limited, but it is preferably a heat treatment (baking) at a temperature of 150 to 860 ° C. for several seconds to several tens of minutes. When the temperature and time are within this range, even when an antireflection film is formed on the silicon substrate, the electrode can be easily formed by the fire-through method.
In addition, since the wiring obtained in the wiring formation step can form electrodes even by irradiation with ultraviolet rays or infrared rays, the heat treatment step may be performed by irradiation with ultraviolet rays or infrared rays.
　＜バスバー電極形成工程＞
　本発明の電極形成方法が有するバスバー電極形成工程は、上記バスバー電極用組成物を用いてバスバー電極を形成する工程である。
　上記バスバー電極形成工程としては、例えば、上記バスバー電極用組成物をシリコン基板（反射防止層を具備する場合は反射防止膜）上に塗布して配線（バスバー電極前駆体）を形成する配線形成工程と、得られた配線を熱処理（焼成）してバスバー電極を形成する熱処理工程とを有する方法等が挙げられる。
　ここで、上記配線形成工程および上記熱処理工程における塗布方法や熱処理方法は、いずれも、上記フィンガー電極形成工程において説明した工程と基本的に同様である。 <Bus bar electrode formation process>
The bus bar electrode forming step of the electrode forming method of the present invention is a step of forming a bus bar electrode using the bus bar electrode composition.
As the bus bar electrode forming step, for example, a wiring forming step of forming the wiring (bus bar electrode precursor) by applying the bus bar electrode composition onto a silicon substrate (an anti-reflection film when an anti-reflection layer is provided). And a method including a heat treatment step of forming a bus bar electrode by heat-treating (firing) the obtained wiring.
Here, the coating method and the heat treatment method in the wiring formation step and the heat treatment step are basically the same as the steps described in the finger electrode formation step.
 〔太陽電池セル〕
　本発明の太陽電池セルは、受光面側の表面電極、半導体基板および裏面電極を具備し、少なくとも上記表面電極が、上述した本発明のセット組成物を使用し、上述した本発明の電極形成方法を用いて形成される太陽電池セルである。
　ここで、本発明の太陽電池セルは、上述した本発明のセット組成物を全裏面電極型（いわゆるバックコンタクト型）太陽電池の裏面電極の形成にも適用することができるため、全裏面電極型の太陽電池にも適用することができる。
　以下に、本発明の太陽電池セルの構成について図１および図２を用いて説明する。なお、図１では、結晶系シリコン太陽電池を例に挙げて、本発明の太陽電池セルを説明するが、これに限られることはなく、例えば、薄膜系のアモルファスシリコン太陽電池、ハイブリッド型（ＨＩＴ）太陽電池等であってもよい。 [Solar cells]
The solar cell of the present invention comprises a surface electrode on the light-receiving surface side, a semiconductor substrate and a back electrode, and at least the surface electrode uses the set composition of the present invention described above, and the electrode forming method of the present invention described above. It is a solar battery cell formed using.
Here, since the solar battery cell of the present invention can be applied to the formation of the back electrode of the all back electrode type (so-called back contact type) solar cell, the above-described set composition of the present invention can be applied to the all back electrode type. This can also be applied to solar cells.
Below, the structure of the photovoltaic cell of this invention is demonstrated using FIG. 1 and FIG. In FIG. 1, the solar cell of the present invention will be described by taking a crystalline silicon solar cell as an example. However, the present invention is not limited to this. For example, a thin-film amorphous silicon solar cell, a hybrid type (HIT) It may be a solar cell or the like.
　図１に示すように、本発明の太陽電池セル１０は、受光面側の表面電極１（フィンガー電極１ａ）と、ｎ層３およびｐ層５が接合したｐｎ接合シリコン基板４（以下、これらを併せて「結晶系シリコン基板７」ともいう。）と、裏面電極６（全面電極６ａ）とを具備するものである。なお、図１は、図２のＩ－Ｉ線における模式的な断面図である。
　また、図１に示すように、本発明の太陽電池セル１０は、反射率低減のためピラミッド状のテクスチャが形成された反射防止膜２を具備するのが好ましい。 As shown in FIG. 1, a solar cell 10 of the present invention includes a surface electrode 1 (finger electrode 1a) on the light receiving surface side, a pn junction silicon substrate 4 in which an n layer 3 and a p layer 5 are joined (hereinafter referred to as these). In addition, it is also referred to as “crystalline silicon substrate 7”) and a back electrode 6 (full surface electrode 6a). FIG. 1 is a schematic cross-sectional view taken along the line II of FIG.
Moreover, as shown in FIG. 1, it is preferable that the photovoltaic cell 10 of this invention comprises the anti-reflective film 2 in which the pyramid-like texture was formed for the reflectance reduction.
　図２（Ａ）に示すように、本発明の太陽電池セル１０は、受光面側の表面電極１として、フィンガー電極１ａとバスバー電極１ｂとを具備するものである。
　また、図２（Ｂ）および図１に示すように、本発明の太陽電池セル１０は、裏面電極６として、全面電極６ａと接続部６ｂとを具備するものである。 As shown in FIG. 2A, the solar battery cell 10 of the present invention includes a finger electrode 1a and a bus bar electrode 1b as the surface electrode 1 on the light receiving surface side.
Moreover, as shown in FIG. 2B and FIG. 1, the solar battery cell 10 of the present invention includes a full-surface electrode 6 a and a connecting portion 6 b as the back electrode 6.
　＜表面電極／裏面電極＞
　本発明の太陽電池セルが具備する表面電極および／または裏面電極は、少なくとも表面電極が本発明のセット組成物を用いて形成されていれば、電極の配置（ピッチ）、形状、高さ、幅等は特に限定されない。
　ここで、図１および図２に示す態様においては、少なくとも、フィンガー電極１ａおよびバスバー電極１ｂを有する表面電極１を本発明のセット組成物を用いて形成することになる。
　一方、裏面電極６は、本発明のセット組成物を用いて形成してもよいが、アルミニウム電極で全面電極６ａを形成し、銀電極で接続部６ｂを形成するのが好ましい。 <Front electrode / Back electrode>
If the surface electrode and / or back electrode which the photovoltaic cell of this invention comprises is at least the surface electrode formed using the set composition of this invention, arrangement | positioning (pitch), shape, height, width of an electrode Etc. are not particularly limited.
Here, in the embodiment shown in FIGS. 1 and 2, at least the surface electrode 1 having the finger electrodes 1a and the bus bar electrodes 1b is formed using the set composition of the present invention.
On the other hand, the back electrode 6 may be formed using the set composition of the present invention, but it is preferable to form the entire surface electrode 6a with an aluminum electrode and the connecting portion 6b with a silver electrode.
　＜反射防止膜＞
　本発明の太陽電池セルが具備していてもよい反射防止膜は、受光面の表面電極が形成されていない部分に形成される膜（膜厚：０．０５～０．１μｍ程度）であって、例えば、シリコン酸化膜、シリコン窒化膜、酸化チタン膜、これらの積層膜等から構成されるものである。 <Antireflection film>
The antireflection film that the solar battery cell of the present invention may have is a film (film thickness: about 0.05 to 0.1 μm) formed on a portion of the light receiving surface where the surface electrode is not formed. For example, a silicon oxide film, a silicon nitride film, a titanium oxide film, or a laminated film thereof.
　＜結晶系シリコン基板＞
　本発明の太陽電池セルが具備する結晶系シリコン基板は特に限定されず、太陽電池を形成するための公知のシリコン基板（板厚：１００～４５０μｍ程度）を用いることができ、また、単結晶または多結晶のいずれのシリコン基板であってもよい。 <Crystal silicon substrate>
The crystalline silicon substrate included in the solar battery cell of the present invention is not particularly limited, and a known silicon substrate (plate thickness: about 100 to 450 μm) for forming a solar battery can be used. Any polycrystalline silicon substrate may be used.
　また、上記結晶系シリコン基板はｐｎ接合を有するが、これは、第１導電型の半導体基板の表面側に第２導電型の受光面不純物拡散領域が形成されていることを意味する。なお、第１導電型がｎ型の場合には、第２導電型はｐ型であり、第１導電型がｐ型の場合には、第２導電型はｎ型である。
　ここで、ｐ型を与える不純物としては、ホウ素、アルミニウム等が挙げられ、ｎ型を与える不純物としては、リン、砒素などが挙げられる。 The crystalline silicon substrate has a pn junction, which means that a second conductivity type light-receiving surface impurity diffusion region is formed on the surface side of the first conductivity type semiconductor substrate. When the first conductivity type is n-type, the second conductivity type is p-type. When the first conductivity type is p-type, the second conductivity type is n-type.
Here, examples of the impurity imparting p-type include boron and aluminum, and examples of the impurity imparting n-type include phosphorus and arsenic.
 〔太陽電池モジュール〕
　本発明の太陽電池モジュールは、表面が半田で被覆されたインターコネクタを用いて本発明の太陽電池セルを直列に接合した太陽電池モジュールである。
　以下に、本発明の太陽電池モジュールの構成について図３を用いて説明する。 [Solar cell module]
The solar cell module of the present invention is a solar cell module in which the solar cells of the present invention are joined in series using an interconnector whose surface is coated with solder.
Below, the structure of the solar cell module of this invention is demonstrated using FIG.
　図３に示すように、本発明の太陽電池モジュール２０は、金属リボン８ｂの表面を半田８ａで被覆したインターコネクタ８を用いて、太陽電池セル１０を直列に接合したものである。
　ここで、金属リボンとしては、具体的には、例えば、導電性接着剤をコートした銅やアルミニウムリボン等を好適に用いることができる。
　また、図３における接合部の拡大断面図に示すように、表面電極１のバスバー電極１ｂとインターコネクタ８の半田８ａとが密着しており、裏面電極６の接続部６ｂとインターコネクタ８の半田８ａとが密着している。 As shown in FIG. 3, the solar cell module 20 of the present invention is obtained by joining solar cells 10 in series using an interconnector 8 in which the surface of a metal ribbon 8b is covered with solder 8a.
Here, specifically, for example, copper or aluminum ribbon coated with a conductive adhesive can be suitably used as the metal ribbon.
3, the bus bar electrode 1b of the front surface electrode 1 and the solder 8a of the interconnector 8 are in close contact with each other, and the connecting portion 6b of the back electrode 6 and the solder of the interconnector 8 are in contact with each other. 8a is in close contact.
　本発明の太陽電池モジュールは、バスバー電極（および裏面電極の接続部）が上記バスバー電極用組成物を用いて形成されているため、インターコネクタの半田との密着性が良好となり、容易にモジュール化することができる。 In the solar cell module of the present invention, since the bus bar electrode (and the connection portion of the back electrode) is formed using the above-mentioned bus bar electrode composition, the adhesion with the solder of the interconnector is good, and it is easily modularized. can do.
　以下、実施例を用いて、本発明のセット組成物および太陽電池セルについて詳細に説明する。ただし、本発明はこれに限定されるものではない。 Hereinafter, the set composition and the solar battery cell of the present invention will be described in detail using examples. However, the present invention is not limited to this.
　（フィンガー電極用組成物Ａ１～Ａ５の調製）
　ボールミルに、下記第１表に示す導電性粒子等を下記第１表中に示す組成比となるように添加し、これらを混合することによりフィンガー電極用の導電性組成物を調製した。 (Preparation of finger electrode compositions A1 to A5)
A conductive composition for finger electrodes was prepared by adding conductive particles shown in Table 1 below to the ball mill so as to have the composition ratio shown in Table 1 and mixing them.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　第１表中の各成分は、以下のものを使用した。
　・銀粉：ＡｇＣ－１０３（形状：球状、平均粒子径：１．５μｍ、福田金属箔粉工業社製）
　・溶媒：α－テルピネオール
　・酸化亜鉛：ＺｎＯ（平均粒子径２０～４０ｎｍ、テイカ社製）
　・酸化ビスマス：Ｂｉ2Ｏ3（平均粒子径５１ｎｍ、シーアイ化成社製）
　・ペロブスカイト化合物：ＳｒＴｉＯ3（平均粒子径：０．８μｍ、日本化学工業社製
　・導電性酸化亜鉛：ＺｎＯ：Ａｌ（平均粒子径３．５μｍ、本荘ケミカル社製）
　・樹脂バインダー：ＥＣ－１００ＦＴＰ（エチルセルロース樹脂固形分：９％、日新化成社製）
　・ガラスフリット：硼珪酸鉛ガラス粉末 The following were used for each component in Table 1.
Silver powder: AgC-103 (shape: spherical, average particle size: 1.5 μm, manufactured by Fukuda Metal Foil Powder Industry)
Solvent: α-terpineol Zinc oxide: ZnO (average particle size 20-40 nm, manufactured by Teica)
-Bismuth oxide: Bi 2 O 3 (average particle size 51 nm, manufactured by CI Kasei Co., Ltd.)
Perovskite compound: SrTiO 3 (average particle size: 0.8 μm, manufactured by Nippon Chemical Industry Co., Ltd.) Conductive zinc oxide: ZnO: Al (average particle size: 3.5 μm, manufactured by Honjo Chemical Co., Ltd.)
Resin binder: EC-100FTP (ethyl cellulose resin solid content: 9%, manufactured by Nisshin Kasei Co., Ltd.)
・ Glass frit: lead borosilicate glass powder
　（バスバー電極用組成物Ｂ１～Ｂ４の調製）
　ボールミルに、下記第２表に示す導電性粒子等を下記第２表中に示す組成比となるように添加し、これらを混合することによりバスバー電極用の導電性組成物を調製した。
　なお、下記第２表中の各成分は、上記第１表と同じものを使用した。 (Preparation of bus bar electrode compositions B1 to B4)
To the ball mill, conductive particles shown in Table 2 below were added so as to have the composition ratio shown in Table 2 below, and these were mixed to prepare a conductive composition for a bus bar electrode.
In addition, each component in the following 2nd table used the same thing as the said 1st table | surface.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　（実施例１～７、比較例１～２）
　まず、シリコン基板（単結晶シリコンウェハー、ＬＳ－２５ＴＶＡ、１５６ｍｍ×１５６ｍｍ×２００μｍ、信越化学工業社製）を準備し、裏面の全面にアルミニウムペーストをスクリーン印刷で塗布し、乾燥させた。
　次いで、シリコン基板の表面に、調製した各導電性組成物を下記第３表に示す組み合わせに従って、スクリーン印刷で塗布することにより、フィンガー電極の所定の配線パターンおよびバスバー電極の所定の配線パターンを形成した。
　スクリーン印刷で配線を形成した後、焼成炉にてピーク温度７４０℃の条件で６０秒間焼成し、導電性の配線（フィンガー電極およびバスバー電極）を形成させた太陽電池セルのサンプルを作製した。 (Examples 1-7, Comparative Examples 1-2)
First, a silicon substrate (single crystal silicon wafer, LS-25TVA, 156 mm × 156 mm × 200 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) was prepared, and an aluminum paste was applied to the entire back surface by screen printing and dried.
Next, a predetermined wiring pattern of finger electrodes and a predetermined wiring pattern of bus bar electrodes are formed on the surface of the silicon substrate by applying the prepared conductive compositions by screen printing according to the combinations shown in Table 3 below. did.
After wiring was formed by screen printing, a sample of a solar battery cell in which conductive wiring (finger electrodes and bus bar electrodes) was formed by baking for 60 seconds in a baking furnace at a peak temperature of 740 ° C. was produced.
　＜半田密着性＞
　作製した太陽電池セルのサンプルのバスバー電極上に、半田ゴテを用いて半田リボン（組成：Ｓｎ－３Ａｇ－０．５Ｃｕ）を実装した。
　その後、ＪＩＳ Ｋ６８５０：１９９９に準じて、引張速度５０ｍｍ／分で引張せん断試験を行い、破断時の荷重（ＭＰａ）を測定した。結果を下記第３表に示す。
　ここで、破断時の荷重が１５ＭＰａ以上であると、太陽電池セルのモジュール化に必要な半田密着性を有していると評価できる。 <Solder adhesion>
A solder ribbon (composition: Sn-3Ag-0.5Cu) was mounted on the bus bar electrode of the solar cell sample produced using a soldering iron.
Thereafter, according to JIS K6850: 1999, a tensile shear test was performed at a tensile speed of 50 mm / min, and the load at break (MPa) was measured. The results are shown in Table 3 below.
Here, when the load at the time of breakage is 15 MPa or more, it can be evaluated that it has solder adhesion necessary for modularization of the solar battery cell.
　＜曲線因子（ＦＦ），光電変換効率（Ｅｆｆ）＞
　作製した各太陽電池セルのサンプルの電気特性（Ｉ－Ｖ特性）をセルテスター（山下電送社製）用いて評価し、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）を求めた。結果を下記第３表に示す。なお、下記第３表中の数値は、比較例２で作製した太陽電池セルのサンプルの結果を１００とした時の相対評価で表す。 <Curve factor (FF), photoelectric conversion efficiency (Eff)>
The electrical characteristics (IV characteristics) of the solar cell samples thus prepared were evaluated using a cell tester (manufactured by Yamashita Dentsu Co., Ltd.) to determine the fill factor (FF) and photoelectric conversion efficiency (Eff). The results are shown in Table 3 below. In addition, the numerical value in the following 3rd table | surface is represented by relative evaluation when the result of the sample of the photovoltaic cell produced by the comparative example 2 is set to 100. FIG.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　第１表～第３表に示す結果から、バスバー電極の形成にも金属酸化物の含有量の多い導電性組成物（Ａ１）を用いると、基準となる比較例２の太陽電池セルのサンプルと比較して、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）は改善するものの、半田密着性が極めて劣ることが分かった（比較例１）。
　これに対し、フィンガー電極に形成に金属酸化物の含有量の多い導電性組成物（Ａ１～Ａ５）を用い、バスバー電極の形成に金属酸化物の含有量の少ない導電性組成物（Ｂ１～Ｂ４）を用いると、半田密着性に優れた電極を形成することができ、曲線因子（ＦＦ）および光電変換効率（Ｅｆｆ）に優れた太陽電池セルを作製できることが分かった（実施例１～７）。 From the results shown in Tables 1 to 3, when the conductive composition (A1) having a high content of metal oxide is used for the formation of the bus bar electrode, In comparison, although the fill factor (FF) and the photoelectric conversion efficiency (Eff) were improved, it was found that the solder adhesion was extremely inferior (Comparative Example 1).
On the other hand, conductive compositions (A1 to A5) having a high content of metal oxide are used for forming finger electrodes, and conductive compositions (B1 to B4) having a low content of metal oxide are used for forming bus bar electrodes. ) Can be used to form electrodes with excellent solder adhesion, and solar cells with excellent fill factor (FF) and photoelectric conversion efficiency (Eff) can be produced (Examples 1 to 7). .
　１　表面電極
　１ａ　フィンガー電極
　１ｂ　バスバー電極
　２　反射防止膜
　３　ｎ層
　４　ｐｎ接合シリコン基板
　５　ｐ層
　６　裏面電極
　６ａ　全面電極（アルミニウム電極）
　６ｂ　接続部（銀電極）
　７　結晶系シリコン基板
　８　インターコネクタ
　８ａ　半田
　８ｂ　金属リボン
　１０　太陽電池セル
　２０　太陽電池モジュール DESCRIPTION OF SYMBOLS 1 Front electrode 1a Finger electrode 1b Bus bar electrode 2 Antireflection film 3 N layer 4 Pn junction silicon substrate 5 P layer 6 Back electrode 6a Whole surface electrode (aluminum electrode)
6b Connection part (silver electrode)
7 Crystalline silicon substrate 8 Interconnector 8a Solder 8b Metal ribbon 10 Solar cell 20 Solar cell module

Claims (4)

  1. 　少なくとも導電性粒子（Ａ）、ガラスフリット（Ｂ）および溶媒（Ｃ）を含有する太陽電池集電電極形成用導電性組成物を用いて太陽電池集電電極を形成する太陽電池集電電極形成方法であって、
    　前記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３～１０質量部含有するフィンガー電極形成用導電性組成物を用いてフィンガー電極を形成するフィンガー電極形成工程と、
    　前記フィンガー電極形成工程の後に、前記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３質量部未満含有するバスバー電極形成用導電性組成物を用いてバスバー電極を形成するバスバー電極形成工程と、を有する太陽電池集電電極形成方法。     Solar cell collector electrode forming method for forming solar cell collector electrode using conductive composition for forming solar cell collector electrode containing at least conductive particles (A), glass frit (B) and solvent (C) Because
    A finger electrode forming step of forming a finger electrode using a conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A);
    After the finger electrode forming step, a bus bar electrode is formed using a bus bar electrode forming conductive composition containing less than 3 parts by mass of the metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). And a bus bar electrode forming step.
  2. 　少なくとも導電性粒子（Ａ）、ガラスフリット（Ｂ）および溶媒（Ｃ）を含有する太陽電池集電電極形成用導電性組成物のセットであって、
    　前記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３～１０質量部含有するフィンガー電極形成用導電性組成物と、
    　前記導電性粒子（Ａ）１００質量部に対して金属酸化物（Ｄ）を３質量部未満含有するバスバー電極形成用導電性組成物と、を有する太陽電池集電電極形成用導電性組成物のセット。     A set of conductive compositions for forming a solar cell collecting electrode, comprising at least conductive particles (A), glass frit (B) and solvent (C),
    A conductive composition for forming a finger electrode containing 3 to 10 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A);
    A conductive composition for forming a solar cell collector electrode, comprising: a conductive composition for forming a bus bar electrode containing less than 3 parts by mass of a metal oxide (D) with respect to 100 parts by mass of the conductive particles (A). set.
  3. 　受光面側の表面電極、半導体基板および裏面電極を具備し、
    　少なくとも前記表面電極が、請求項２に記載の太陽電池集電電極形成用導電性組成物のセットを使用し、請求項１に記載の太陽電池集電電極形成方法を用いて形成される太陽電池セル。     It comprises a surface electrode on the light receiving surface side, a semiconductor substrate and a back electrode,
    The solar cell formed by using the set of the conductive composition for forming a solar cell collecting electrode according to claim 2 and using the method for forming a solar cell collecting electrode according to claim 1 at least. cell.
  4. 　表面が半田で被覆されたインターコネクタを用いて請求項３に記載の太陽電池セルを直列に接合した太陽電池モジュール。 The solar cell module which joined the photovoltaic cell of Claim 3 in series using the interconnector by which the surface was coat | covered with the solder.
PCT/JP2012/051235 2011-04-25 2012-01-20 Method for forming solar cell collecting electrode, set of conductive compositions for forming solar cell collecting electrode, and solar cell WO2012147378A1 (en)

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