JP6357599B1 - Conductive paste - Google Patents

Abstract

Even if a bus bar electrode of a solar cell produced by a resin-type conductive paste using silver-coated copper powder is connected to a tab wire by soldering, a reduction in conversion efficiency of the solar cell can be prevented. A conductive paste is provided. A silver-coated copper powder and a resin in which the surface of a copper powder having a volume-based cumulative 50% particle diameter (D50 diameter) of 0.1 to 15 μm measured by a laser diffraction particle size distribution device is coated with a silver layer. In the conductive paste comprising, an epoxy resin having a naphthalene skeleton is used as the resin, and preferably at least one of imidazole and boron trifluoride amine curing agent is added as a curing agent. [Selection] Figure 2

Description

  The present invention relates to a conductive paste, and more particularly to a conductive paste using silver-coated copper powder as a conductive metal powder.

  Conventionally, in order to form electrodes and wiring of electronic parts by printing methods, etc., conductive pastes prepared by blending a conductive metal powder such as silver powder or copper powder with a solvent, resin, dispersant, etc. have been used. .

  However, although silver powder has a very small volume resistivity and is a good conductive material, it is a noble metal powder, and thus costs are high. On the other hand, copper powder has a low volume resistivity and is a good conductive material. However, since it is easily oxidized, it has poor storage stability (reliability) compared to silver powder.

  In order to solve these problems, silver-coated copper powder in which the surface of the copper powder is coated with silver has been proposed as a metal powder used for the conductive paste (see, for example, Patent Documents 1 and 2).

  In recent years, it has been attempted to use a conductive paste using silver-coated copper powder, which is cheaper than silver powder, instead of a conductive paste using silver powder as a conductive paste for forming bus bar electrodes for solar cells. .

  In general crystalline silicon type solar cells, electrodes are formed by firing a baking type conductive paste using silver powder at a high temperature of about 800 ° C. in an air atmosphere. When using conductive paste that uses copper, copper powder and silver-coated copper powder will oxidize when firing at such high temperatures in an air atmosphere, so special techniques such as firing in an inert atmosphere Is required and the cost is high.

  On the other hand, in HIT (single crystal hybrid type) solar cells, etc., electrodes are generally formed by heating a resin-curing conductive paste using silver powder to about 200 ° C. in an air atmosphere and curing it. Copper powder and silver-coated copper powder can withstand oxidation even when heated at such a low temperature in an air atmosphere, making it possible to use resin-cured conductive paste using silver-coated copper powder Become.

  In addition, when an electrode formed from a conventional resin-curing conductive paste is connected to a tab wire to produce a HIT solar cell, the soldering temperature (380 ° C.) The resin of the conductive paste is decomposed at a degree), and the electrode and the tab wire are connected using a conductive adhesive that is more expensive than solder.

JP 2010-174411 A (paragraph number 0003) JP 2010-077745 (paragraph number 0006)

  A HIT solar cell is manufactured by connecting a bus bar electrode formed of a resin-type conductive paste using silver-coated copper powder as a conductive filler and using a bisphenol A type epoxy resin as a resin to a tab wire with a conductive adhesive. As a result, it was found that the solar cell had a high conversion efficiency equivalent to that when silver powder was used.

  However, if the bus bar electrode formed by the resin-type conductive paste obtained by kneading the silver-coated copper powder and the bisphenol A type epoxy resin as described above is connected to the tab wire by soldering, the resistance of the bus bar electrode is reduced. It turned out that the conversion efficiency of a solar cell may fall and it may become high. In addition, such a problem does not occur when silver powder is used instead of the silver-coated copper powder of the resin-type conductive paste.

  Therefore, in view of such a problem, the present invention provides a solar cell bus bar electrode made of a resin-type conductive paste using silver-coated copper powder and connected to the tab wire by soldering. It aims at providing the electrically conductive paste which can prevent the fall of conversion efficiency.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have found that a resin-type conductive paste comprising a silver-coated copper powder whose surface is coated with a silver layer and an epoxy resin having a naphthalene skeleton. Thus, when the bus bar electrode of the solar cell is manufactured, even if the bus bar electrode is connected to the tab wire by soldering, it is found that the conversion efficiency of the solar cell can be prevented from being lowered, and the present invention has been completed.

That is, the conductive paste according to the present invention is characterized in that it contains silver-coated copper powder whose surface is coated with a silver layer and an epoxy resin having a naphthalene skeleton. This conductive paste preferably contains a solvent. Moreover, it is preferable that this electrically conductive paste contains a hardening | curing agent, and it is preferable that this hardening | curing agent is at least one of an imidazole and a boron trifluoride amine type hardening | curing agent. Is preferably the amount of silver is 5 mass% or more to silver-coated copper powder, 50% cumulative particle diameter on a volume basis as measured by a laser diffraction type particle size distribution apparatus copper powder (D ₅₀ diameter) 0.1~15μm Is preferred. The amount of the silver-coated copper powder in the conductive paste is preferably 50 to 90% by mass.

  Moreover, the manufacturing method of the electrode for solar cells by this invention forms an electrode on the surface of a board | substrate by hardening after apply | coating said electrically conductive paste to a board | substrate.

  According to the present invention, even if a solar cell bus bar electrode made of a resin-type conductive paste using silver-coated copper powder is connected to a tab wire by soldering, a reduction in conversion efficiency of the solar cell can be prevented. An electrically conductive paste can be provided.

It is a figure which shows the scanning electron microscope (SEM) image of the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module produced in the comparative example 8. FIG. It is a figure which shows the SEM image of the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module produced in Example 5. FIG. It is a figure which shows Ag map image by the mapping analysis of the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module produced in Example 5. FIG. It is a figure which shows Cu map image by the mapping analysis of the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module produced in Example 5. FIG.

  The embodiment of the conductive paste according to the present invention includes silver-coated copper powder whose surface is coated with a silver layer and an epoxy resin having a naphthalene skeleton.

  As a resin having a naphthalene skeleton contained in the conductive paste, an epoxy resin having a naphthalene skeleton as shown in Chemical Formula 1 (for example, HP4710 manufactured by Dainippon Ink & Chemicals, Inc.) can be used. The content of the epoxy resin having a naphthalene skeleton is preferably 1 to 20% by mass, and more preferably 3 to 10% by mass with respect to the conductive paste. If the content of the epoxy resin having a naphthalene skeleton is too small, the function of protecting the surface of the silver-coated copper powder from oxidation due to heat becomes insufficient. On the other hand, if the amount is too large, the printability when printing the bus bar electrode shape of the solar cell with the conductive paste and the adhesive strength of the solder when soldering the bus bar electrode to the tab wire are deteriorated, and the conductive paste is used. The resistance of the bus bar electrode of the solar cell increased. Whether or not the epoxy resin has a naphthalene skeleton can be identified by a gas chromatograph mass spectrometer (GC-MS) or C13-NMR.

  The conductive paste preferably contains a curing agent, and it is preferable to use at least one of imidazole and boron trifluoride amine curing agent as the curing agent. The content of the curing agent is preferably 1 to 10% by mass and more preferably 2 to 6% by mass with respect to the epoxy resin.

  This conductive paste preferably contains a solvent, and this solvent can be appropriately selected according to the purpose of use of the conductive paste. For example, butyl carbitol acetate (BCA), butyl carbitol (BC), ethyl carbitol acetate (ECA), ethyl carbitol (EC), toluene, methyl ethyl ketone, methyl isobutyl ketone, tetradecane, tetralin, propyl alcohol, isopropyl alcohol, One or more solvents can be selected and used from dihydroterpineol, dihydroterpineol acetate, ethyl carbitol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (texanol), and the like. The content of the solvent is preferably 0 to 20% by mass and more preferably 0 to 10% by mass with respect to the conductive paste.

  The conductive paste may contain other components such as a surfactant, a dispersant, a rheology modifier, a silane coupling agent, and an ion collector.

  In the conductive paste, silver-coated copper powder whose surface is coated with a silver layer is used as a conductor. The shape of the copper powder coated with the silver layer (silver-coated copper powder) may be substantially spherical or flaky.

  The silver layer is preferably a layer made of silver or a silver compound, and more preferably a layer made of 90% by mass or more of silver. The amount of silver with respect to the silver-coated copper powder is preferably 5% by mass or more, more preferably 7 to 50% by mass, further preferably 8 to 40% by mass, and 9 to 20% by mass. Most preferably. If the amount of silver is less than 5% by mass, the conductivity of the silver-coated copper powder is adversely affected. On the other hand, if it exceeds 50 mass%, the cost increases due to an increase in the amount of silver used, which is not preferable.

Particle size of the copper powder is preferably 50% cumulative particle diameter on a volume basis as measured by a laser diffraction type particle size distribution apparatus _{(D 50} diameter) is 0.1-15, and even a 0.3~10μm More preferably, it is 1-5 micrometers most preferable. A cumulative 50% particle diameter (D ₅₀ diameter) of less than 0.1 μm is not preferable because it adversely affects the conductivity of the silver-coated copper powder. On the other hand, if it exceeds 15 μm, it is not preferable because formation of fine wiring becomes difficult.

  Copper powder may be manufactured by wet reduction, electrolysis, vapor phase, etc., but rapidly solidifies by dissolving copper above the melting temperature and colliding with high-pressure gas or high-pressure water while dropping from the bottom of the tundish. It is preferable to produce by a so-called atomizing method (such as a gas atomizing method or a water atomizing method) to obtain a fine powder. In particular, when manufactured by the so-called water atomization method in which high-pressure water is sprayed, copper powder having a small particle diameter can be obtained. Therefore, when copper powder is used in a conductive paste, the conductivity is improved by increasing the contact points between the particles. Can be achieved.

  As a method of coating copper powder with a silver layer, a method of depositing silver or a silver compound on the surface of copper powder by a substitution method using a substitution reaction of copper and silver or a reduction method using a reducing agent may be used. For example, a method of precipitating silver or a silver compound on the surface of copper powder while stirring a solution containing copper powder and silver or a silver compound in a solvent, or a solution containing copper powder and an organic substance in a solvent and a solvent A method of depositing silver or a silver compound on the surface of copper powder while mixing and stirring a solution containing silver or a silver compound and an organic substance can be used.

  As this solvent, water, an organic solvent, or a solvent in which these are mixed can be used. When using a mixed solvent of water and organic solvent, it is necessary to use an organic solvent that becomes liquid at room temperature (20 to 30 ° C.). The mixing ratio of water and organic solvent depends on the organic solvent used. It can be adjusted appropriately. In addition, as water used as a solvent, distilled water, ion-exchanged water, industrial water, or the like can be used as long as there is no fear that impurities are mixed therein.

  Since silver ions need to be present in the solution as a raw material for the silver layer, it is preferable to use silver nitrate having high solubility in water and many organic solvents. In addition, in order to perform the reaction to coat copper powder with a silver layer (silver coating reaction) as uniformly as possible, a silver nitrate solution in which silver nitrate is dissolved in a solvent (water, an organic solvent or a mixture of these) instead of solid silver nitrate Is preferably used. The amount of silver nitrate solution to be used, the concentration of silver nitrate in the silver nitrate solution, and the amount of organic solvent can be determined according to the amount of the target silver layer.

  In order to form the silver layer more uniformly, a chelating agent may be added to the solution. As the chelating agent, it is preferable to use a chelating agent having a high complex stability constant with respect to copper ions or the like so that copper ions or the like by-produced by substitution reaction between silver ions and metallic copper do not reprecipitate. . In particular, since the copper powder serving as the core of the silver-coated copper powder contains copper as a main component, it is preferable to select a chelating agent while paying attention to the complex stability constant with copper. Specifically, a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid, diethylenetriamine, triethylenediamine, and salts thereof can be used as the chelating agent.

  In order to perform the silver coating reaction stably and safely, a pH buffer may be added to the solution. As this pH buffering agent, ammonium carbonate, ammonium hydrogen carbonate, aqueous ammonia, sodium hydrogen carbonate, or the like can be used.

  During the silver coating reaction, stir copper powder in the solution before adding the silver salt, and add the solution containing the silver salt while the copper powder is sufficiently dispersed in the solution. Is preferred. The reaction temperature in the silver coating reaction may be a temperature at which the reaction solution is solidified or evaporated, but is preferably set in the range of 10 to 40 ° C, more preferably 15 to 35 ° C. Moreover, although reaction time changes with the quantity and reaction temperature of silver or a silver compound, it can set in the range of 1 minute-5 hours.

  Moreover, after apply | coating to the board | substrate the said electrically conductive paste (The electroconductive paste containing the silver covering copper powder by which the surface of the copper powder was coat | covered with the silver layer, and the epoxy resin which has a naphthalene skeleton), it hardens | cures on the surface of a board | substrate. An electrode is formed, an interconnector is soldered to this electrode, and a cover glass is attached to the surface side (side on which sunlight is incident) of the cell with the interconnector having the interconnector soldered to this electrode via a protective sheet. By laminating, a solar cell module can be manufactured. As the protective sheet, it is preferable to use a polyolefin-based film such as a cycloolefin copolymer (COC) film. Polyolefin film is known to allow oxygen to pass through, but the above conductive paste (conducting paste containing silver-coated copper powder with a copper layer coated with a silver layer and an epoxy resin having a naphthalene skeleton) It was found that when a polyolefin-based film was used as a protective sheet for a solar cell module using an electrode formed from), the oxidation of the electrode was suppressed and the performance as a solar cell could be maintained.

  Hereinafter, the Example of the electrically conductive paste by this invention is described in detail.

[Example 1]
When a commercially available copper powder manufactured by the atomizing method (atomized copper powder SF-Cu 5 μm manufactured by Nippon Atomizing Co., Ltd.) was prepared and the particle size distribution of this copper powder (before silver coating) was determined, The volume-based cumulative 10% particle size (D ₁₀ ) was 2.26 μm, the cumulative 50% particle size (D ₅₀ ) was 5.20 μm, and the cumulative 90% particle size (D ₉₀ ) was 9.32 μm. The particle size distribution of the copper powder was measured with a laser diffraction particle size distribution device (Microtrack particle size distribution measurement device MT-3300 manufactured by Nikkiso Co., Ltd.), and the volume-based cumulative 10% particle diameter (D ₁₀ ), cumulative The 50% particle diameter (D ₅₀ ) and the cumulative 90% particle diameter (D ₉₀ ) were determined.

  Further, silver nitrate containing 16.904 kg of silver in a solution (solution 1) obtained by dissolving 2.6 kg of ammonium carbonate in 450 kg of pure water, 319 kg of EDTA-4Na (43%) and 76 kg of ammonium carbonate in 284 kg of pure water. A solution (solution 2) obtained by adding 92 kg of an aqueous solution was prepared.

  Next, in a nitrogen atmosphere, 100 kg of the above copper powder was added to the solution 1 and heated to 35 ° C. while stirring. The solution 2 was added to the solution in which the copper powder was dispersed and stirred for 30 minutes, followed by filtration, washing with water, and drying to obtain a copper powder coated with silver (silver-coated copper powder). The water washing was performed until the solid content obtained by filtration was poured with pure water until the potential of the liquid after the water washing was 0.5 mS / m or less.

  The silver-coated copper powder (5.0 g) thus obtained was dissolved in 40 mL of nitric acid aqueous solution obtained by diluting a nitric acid aqueous solution having a specific gravity of 1.38 with a pure water so as to have a volume ratio of 1: 1, and boiled with a heater to obtain silver. After completely dissolving the coated copper powder, to this aqueous solution, a hydrochloric acid aqueous solution having a specific gravity of 1.18 was added little by little to a hydrochloric acid aqueous solution diluted with pure water so as to have a volume ratio of 1: 1, thereby precipitating silver chloride. The addition of an aqueous hydrochloric acid solution was continued until no precipitation occurred, and the content of Ag was determined from the obtained silver chloride by a gravimetric method. The Ag content in the silver-coated copper powder was 10.14% by mass.

Further, 0.1 g of this silver-coated copper powder is added to 40 mL of isopropyl alcohol, and dispersed for 2 minutes by an ultrasonic homogenizer (tip tip diameter: 20 mm), and then the particle size distribution of the silver-coated copper powder is measured by a laser diffraction particle size distribution device ( Measurement was performed with a Microtrac particle size distribution measuring device MT-3300 manufactured by Nikkiso Co., Ltd. As a result, the volume-based cumulative 10% particle diameter (D ₁₀ ) of the silver-coated copper powder is 2.5 μm, the cumulative 50% particle diameter (D ₅₀ ) is 5.2 μm, and the cumulative 90% particle diameter (D ₉₀ ) is 10. .1 μm.

Further, the BET specific surface area of the silver-coated copper powder was measured by a BET one-point method using a BET specific surface area measuring device (4-sorb US manufactured by Yuasa Ionics Co., Ltd.). As a result, the BET specific surface area of the silver-coated copper powder was 0.31 m ² / g.

  Moreover, 87.64 parts by weight of the obtained silver-coated copper powder, 6.49 parts by weight of an epoxy resin having a naphthalene skeleton shown in Chemical Formula 1 (HP 4710 manufactured by Dainippon Ink and Chemicals, Inc.), and butyl carbitol as a solvent 5.52 parts by weight of acetate (manufactured by Wako Pure Chemical Industries, Ltd.), 0.25 parts by weight of imidazole (2E4MZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing agent, and oleic acid (Wako Pure Chemical Industries, Ltd.) as a dispersant 0.10 parts by weight was mixed (preliminary kneading) with a self-revolving vacuum stirring deaerator (Shinky Co., Ltd., Awatori Netaro), then three rolls (EXAKT80S manufactured by Ottoman) The conductive pastes 1 were obtained (as bus bar electrode pastes) by kneading with the above. In addition, F value (The ratio of the silver coating copper powder with respect to the total amount of the silver coating copper powder as a conductive filler, resin, and a hardening | curing agent) of this electrically conductive paste 1 will be 92.9%. The viscosity of the conductive paste 1 was measured at 1 rpm at 25 ° C. with a viscometer (DV-III Ultra manufactured by Brookfield, CP52 was used as a cone), and was 40 Pa · s.

  Further, 45 L of industrial ammonia water was added to 502.7 L of a silver nitrate solution of 21.4 g / L as silver ions to produce a silver ammine complex solution. To the resulting silver ammine complex solution, 8.8 L of a sodium hydroxide solution having a concentration of 100 g / L was added to adjust pH, diluted by adding 462 L of water, and 48 L of industrial formalin was added as a reducing agent. Immediately thereafter, 121 g of a 16% by weight stearic acid emulsion was added as stearic acid. The silver slurry thus obtained was filtered, washed with water, and dried to obtain 21.6 kg of silver powder. The silver powder was subjected to a surface smoothing treatment with a Henschel mixer (high-speed stirrer) and then classified to remove silver aggregates larger than 11 μm. The water washing was performed until the solid content obtained by filtration was poured with pure water until the potential of the liquid after the water washing was 0.5 mS / m or less.

  88 parts by weight of the silver powder thus obtained, 0.2 parts by weight of indium powder, 1.5 parts by weight of silver tellurium-coated glass powder, and 0.12 of ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) as a binder resin. Parts by weight and acrylic resin (NISSETSU EU-5638 manufactured by Nippon Carbide Industries Co., Ltd.), 0.5 parts by weight of oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as an additive, and stearin as a thixotropic agent 0.3 parts by weight of magnesium oxide (manufactured by Wako Pure Chemical Industries, Ltd.), 3.4 parts by weight of methyl isobutyl ether (MIBE) (manufactured by JNC Co., Ltd.) and butyl carbitol acetate (manufactured by Wako Pure Chemical Industries, Ltd.) ) 3.4 parts by weight are mixed (preliminary kneading) by a self-revolving vacuum stirring and deaerator (Niwataro Awatori manufactured by Shinky Corporation) After, by kneading by a three-roll (EXAKT80S manufactured by Otto Herman, Inc.), was obtained (as a baking type Ag paste) conductive paste 2.

  Silver tellurium-coated glass powder was produced as follows. First, 3.47 g of a 32% by mass silver nitrate aqueous solution was mixed with 787 g of pure water stirred in a 1 L beaker, and 28% by mass ammonia water as a complexing agent was added to this silver nitrate aqueous solution containing 1.11 g of silver. 2.5 g was added to obtain an aqueous silver ammine complex salt solution. After the liquid temperature of this silver ammine complex salt aqueous solution is 30 ° C., 10 g of tellurium glass powder (BLT-77 manufactured by Asahi Glass Co., Ltd.) is added, and immediately after that, 0.3 g of hydrazine as a reducing agent and silver colloid 10 A mixture of 3 g and 20 g of pure water was added and aged for 5 minutes. After tellurium-based glass powder was coated with a layer mainly composed of silver and tellurium, the slurry containing silver tellurium-coated glass powder was suction filtered. The resulting cake was washed with pure water until the potential became 0.5 mS / m or less, and the resulting cake was dried with a vacuum dryer at 75 ° C. for 10 minutes to obtain silver tellurium-coated glass powder (silver and tellurium as main components). Glass powder coated with a layer to be obtained.

  Next, two silicon wafers (E & M Co., Ltd., 100Ω / □, 6-inch single crystal) are prepared, and aluminum is applied to the back of each silicon wafer by a screen printer (MT-320T manufactured by Microtech Co., Ltd.). After printing the paste (Alsolar 14-7021 manufactured by Toyo Aluminum Co., Ltd.), it was dried with a hot air dryer at 200 ° C. for 10 minutes, and a screen printer (MT- manufactured by Microtech Co., Ltd.) was applied on the surface of the silicon wafer. 320T), the conductive paste 2 is printed in the shape of 100 finger electrodes having a width of 40 μm, and then dried at 200 ° C. for 10 minutes with a hot air dryer, and a high-speed firing IR furnace (manufactured by NGK Corporation) Firing test 4 chamber furnace) In-out 21 sec. Formed. Thereafter, each conductive paste 1 (conductive paste 1 obtained from silver-coated copper powder) was applied to a surface of each silicon wafer by a screen printer (MT-320T manufactured by Microtech Co., Ltd.) with a width of 1.3 mm. After being printed in the shape of the three bus bar electrodes, it was heated at 150 ° C. for 10 minutes by a hot air drier, then heated at 200 ° C. for 30 minutes, dried and cured to form a bus bar electrode. When the resistance (initial resistance value) of the bus bar electrode thus formed was measured, it was 3.15Ω. In addition, a soldering iron at 380 ° C. is applied to the bus bar electrode so that the same level of heat as that applied during soldering is applied to the bus bar electrode of one silicon wafer. When the resistance of the bus bar electrode was measured, it was 3.42Ω, and the rate of change in resistance with respect to the initial resistance value was 109%.

Next, the bus bar electrode and the tab wire of the other silicon wafer were soldered at 380 ° C. with SnPb eutectic solder (melting point 183 ° C.) to produce a solar cell. This solar cell was irradiated with pseudo-sunlight with a light irradiation energy of 100 mW / cm ² by a xenon lamp of a solar simulator (manufactured by Wacom Electric Co., Ltd.), and a battery characteristic test was performed. As a result, the current (short-circuit current) Isc flowing between the two terminals when the output terminal of the solar cell is short-circuited is 9.23 A, and the voltage (open-circuit voltage) Voc between the two terminals when the output terminal of the solar cell is opened. Is 0.631 V, current density Jsc (short-circuit current Isc per cm ² ) is 0.038 A / cm ² , and maximum output Pmax (= Imax · Vmax) is divided by the product of open-circuit voltage Voc and current density Jsc (curve Factor) FF (= Pmax / Voc · Isc) is 73.64, and power generation efficiency Eff (value obtained by dividing the maximum output Pmax by the irradiation light quantity (W) (per 1 cm ² ) by 100) is 17.65. %, The series resistance Rs was 0.0089Ω / □.

[Example 2]
In the same manner as in Example 1, except that imidazole (2PHZ-PW manufactured by Shikoku Kasei Kogyo Co., Ltd.) was used instead of imidazole (2E4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing agent, a solar cell was obtained. Produced. In addition, when the viscosity of the conductive paste 1 obtained in this example was measured by the same method as in Example 1, it was within the range of 40 ± 5 Pa · s.

  When the resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 7.56Ω, and the resistance value after soldering. Was 6.58Ω, and the rate of change in resistance with respect to the initial resistance value was 87%.

Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 9.23 A, the open-circuit voltage Voc was 0.630 V, the current density Jsc was 0.038 A / cm ² , and the curve The factor FF was 72.98, the power generation efficiency Eff was 17.45%, and the series resistance Rs was 0.0091Ω / □.

[Example 3]
Instead of imidazole (2E4MZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) as the curing agent in the conductive paste 1, a boron trifluoride amine-based curing agent (BF3NH2Et manufactured by Wako Pure Chemical Industries, Ltd.) is used, and silver-coated copper Example 1 except that the amounts of powder, epoxy resin having a naphthalene skeleton, solvent and curing agent were 85.52 parts by weight, 8.44 parts by weight, 5.62 parts by weight and 0.32 parts by weight, respectively. A solar cell was produced by the method described above. The F value of the conductive paste 1 obtained in this example was 90.7%. When the viscosity of the conductive paste 1 obtained in this example was measured by the same method as in Example 1, it was within the range of 40 ± 5 Pa · s.

  When the resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 6.58Ω, and the resistance value after soldering Was 7.71Ω, and the rate of change in resistance with respect to the initial resistance value was 117%.

Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 9.20 A, the open-circuit voltage Voc was 0.628 V, the current density Jsc was 0.038 A / cm ² , the curve The factor FF was 71.63, the power generation efficiency Eff was 17.02%, and the series resistance Rs was 0.0102Ω / □.

[Example 4]
Instead of the epoxy resin having a naphthalene skeleton (HP 4710 made by Dainippon Ink & Chemicals, Inc.) in the conductive paste 1, the epoxy resin having a naphthalene skeleton shown in Chemical formula 1 (HP 9500 made by Dainippon Ink & Chemicals, Inc.) A solar cell was produced in the same manner as in Example 1 except that was used. The F value of the conductive paste 1 obtained in this example was 90.9%. When the viscosity of the conductive paste 1 obtained in this example was measured by the same method as in Example 1, it was within the range of 40 ± 5 Pa · s.

  When the resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured, the resistance value of the bus bar electrode before soldering (initial resistance value) was 3.56Ω, and the resistance value after soldering. Was 5.83Ω, and the rate of change in resistance with respect to the initial resistance value was 164%.

Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 8.85 A, the open-circuit voltage Voc was 0.627 V, the current density Jsc was 0.036 A / cm ² , the curve The factor FF was 70.47, the power generation efficiency Eff was 16.10%, and the series resistance Rs was 0.0114Ω / □.

[Comparative Example 1]
In place of the epoxy resin having a naphthalene skeleton in the conductive paste 1, a bisphenol F type epoxy resin shown in Chemical Formula 2 (EP4901E manufactured by ADEKA Corporation) is used, and imidazole (2E4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) is used as a curing agent. A solar cell was prepared in the same manner as in Example 3 except that the amount of the solvent was 1.94 parts by weight so that the viscosity of the conductive paste 1 was in the range of 40 ± 5 Pa · s. did. The F value of the conductive paste 1 is 90.7%.

  When the resistance of the bus bar electrode before and after soldering the tab bar wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 4.05Ω, and the resistance value after soldering. Was 18.70Ω, and the resistance change rate with respect to the initial resistance value was 462%.

Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 6.71 A, the open-circuit voltage Voc was 0.634 V, the current density Jsc was 0.028 A / cm ² , the curve The factor FF was 49.96, the power generation efficiency Eff was 8.74%, and the series resistance Rs was 0.0162Ω / □.

[Comparative Example 2]
Instead of an epoxy resin having a naphthalene skeleton, a bisphenol F type epoxy resin (EP4901E manufactured by ADEKA Corporation) shown in Chemical Formula 2 is used so that the viscosity of the conductive paste 1 is within a range of 40 ± 5 Pa · s. A solar cell was produced in the same manner as in Example 1 except that the amount of the solvent was 1.99 parts by weight.

  When the resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 2.37Ω, and the resistance value after soldering. Was 7.73Ω, and the rate of change in resistance with respect to the initial resistance value was 326%.

Moreover, when the battery characteristic test of the solar cell was performed by the same method as in Example 1, the short-circuit current Isc was 7.93 A, the open-circuit voltage Voc was 0.632 V, the current density Jsc was 0.033 A / cm ² , and the curve The factor FF was 45.47, the power generation efficiency Eff was 9.39%, and the series resistance Rs was 0.0228Ω / □.

[Comparative Example 3]
Instead of an epoxy resin having a naphthalene skeleton, a bisphenol F type epoxy resin (EP4901E manufactured by ADEKA Corporation) shown in Chemical Formula 2 is used so that the viscosity of the conductive paste 1 is within a range of 40 ± 5 Pa · s. A solar cell was produced in the same manner as in Example 3 except that the amount of the solvent was 1.94 parts by weight.

  When the resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 5.95Ω, and the resistance value after soldering. Was 12.63Ω, and the rate of change in resistance with respect to the initial resistance value was 212%.

Moreover, when the battery characteristic test of the solar cell was performed by the same method as in Example 1, the short-circuit current Isc was 8.65 A, the open-circuit voltage Voc was 0.630 V, the current density Jsc was 0.036 A / cm ² , and the curve The factor FF was 64.69, the power generation efficiency Eff was 14.51%, and the series resistance Rs was 0.0165Ω / □.

[Comparative Example 4]
Instead of an epoxy resin having a naphthalene skeleton, a bisphenol A type epoxy resin (JER828, manufactured by Mitsubishi Chemical Corporation) shown in Chemical Formula 3 is used, and the viscosity of the conductive paste 1 is in the range of 40 ± 5 Pa · s. A solar cell was produced in the same manner as in Example 1 except that the amount of the solvent was 1.99 parts by weight.

When the resistance of the bus bar electrode before and after soldering the tab bar wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 3.50Ω, and the resistance value after soldering Was 34.93Ω, and the rate of change in resistance with respect to the initial resistance value was 998%.
Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 7.78 A, the open-circuit voltage Voc was 0.635 V, the current density Jsc was 0.032 A / cm ² , and the curve The factor FF was 54.49, the power generation efficiency Eff was 11.07%, and the series resistance Rs was 0.0181Ω / □.

[Comparative Example 5]
Instead of an epoxy resin having a naphthalene skeleton, an epoxy resin having a biphenyl skeleton shown in Chemical formula 4 (NC-3000-H manufactured by Nippon Kayaku Co., Ltd.) is used, and the viscosity of the conductive paste 1 is 40 ± 5 Pa · s. A solar cell was produced in the same manner as in Example 1 except that the amount of the solvent was changed to 5.32 parts by weight so as to be within the range.

  The resistance of the bus bar electrode before and after soldering the bus bar electrode and the tab wire of this solar cell was measured. The resistance value before soldering of the bus bar electrode (initial resistance value) was 6.08Ω, and the resistance value after soldering. Was 23.53Ω, and the rate of change in resistance with respect to the initial resistance value was 387%.

Moreover, when the battery characteristic test of the solar cell was performed by the same method as in Example 1, the short-circuit current Isc was 5.67 A, the open-circuit voltage Voc was 0.635 V, the current density Jsc was 0.023 A / cm ² , the curve The factor FF was 54.52, the power generation efficiency Eff was 8.07%, and the series resistance Rs was 0.0127Ω / □.

[Comparative Example 6]
Instead of the epoxy resin having a naphthalene skeleton, a cyclopentadiene skeleton epoxy resin (XD-1000 manufactured by Nippon Kayaku Co., Ltd.) shown in Chemical Formula 5 is used, and the viscosity of the conductive paste 1 is in the range of 40 ± 5 Pa · s. A solar cell was produced in the same manner as in Example 1 except that the amount of the solvent was 5.32 parts by weight so as to be inside.

  When the resistance of the bus bar electrode before and after soldering the tab bar wire of this solar cell was measured, the resistance value before soldering of the bus bar electrode (initial resistance value) was 4.73Ω, and the resistance value after soldering. Was 21.67Ω, and the resistance change rate with respect to the initial resistance value was 458%.

Further, when the battery characteristics test of the solar cell was performed in the same manner as in Example 1, the short-circuit current Isc was 4.66 A, the open-circuit voltage Voc was 0.632 V, the current density Jsc was 0.019 A / cm ² , the curve The factor FF was 55.01, the power generation efficiency Eff was 6.67%, and the series resistance Rs was 0.0182Ω / □.

  The results of these Examples and Comparative Examples are shown in Tables 1 to 3.

  As can be seen from Tables 1 to 3, when the conductive pastes of Examples 1 to 3 are used for forming the bus bar electrodes of solar cells, the bus bar electrodes are compared to the case of using the conductive pastes of Comparative Examples 1 to 6. Even if it is connected to the tab wire by soldering, it is possible to prevent the resistance of the bus bar electrode from increasing and to prevent the conversion efficiency of the solar cell from decreasing.

[Example 5]
79.0 parts by weight of the silver-coated copper powder of Example 1, 8.8 parts by weight of silver powder having an average primary particle diameter of 1 μm (Ag-2-IC manufactured by DOWA Electronics Co., Ltd.), and the naphthalene skeleton shown in Chemical Formula 1 6.6 parts by weight of an epoxy resin (HP 4710 manufactured by Dainippon Ink & Chemicals, Inc.), 5.3 parts by weight of butyl carbitol acetate (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent, and imidazole (Shikoku Chemicals) as a curing agent 2E4MZ manufactured by Kogyo Co., Ltd. and 0.1 part by weight of oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersing agent, a self-revolving vacuum stirring deaerator (manufactured by Shinky Corporation) After mixing (preliminary kneading) by Nawataro Nawatori), by kneading with three rolls (EXAKT80S manufactured by Otto Herman), the surface of the silicon wafer described later Was obtained busbar as electrode paste) The conductive paste A. In addition, this electroconductive paste A contains 87.8 mass% of silver covering copper powder and silver powder in total as an electroconductive filler.

  In addition, 88 parts by weight of silver powder (AG-4-8F manufactured by DOWA Electronics Co., Ltd.) having an average primary particle size of 1.9 μm, 2.4 parts by weight of ethyl cellulose resin (manufactured by Wako Pure Chemical Industries, Ltd.), and texanol (JMC 9.5 parts by weight of a solvent in which 1: 1 mixture of butyl carbitol estate (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 part by weight of glass frit (GA-12 manufactured by Nippon Electric Glass Co., Ltd.) And 0.5 part by weight of oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant are mixed (preliminary kneading) by a self-revolving vacuum stirring and defoaming device (Shinky Co., Ltd. After that, by conducting kneading with three rolls (EXAKT80S manufactured by Otto Herman), a conductive pace (as a bus bar electrode paste on the back side of the silicon wafer described later) It was obtained B.

  Furthermore, 87.9 parts by weight of silver powder having an average primary particle size of 1.3 μm (AG-2.5-8F manufactured by DOWA Electronics Co., Ltd.), 0.1 part by weight of ethyl cellulose resin (manufactured by Wako Pure Chemical Industries, Ltd.), 1 part by weight of acrylic resin (EU-5638 manufactured by Nippon Carbide Industries Co., Ltd.), methyl isobutyl ether (MIBE) (manufactured by JNC Co., Ltd.) and butyl carbitol estate (manufactured by Wako Pure Chemical Industries, Ltd.) : 6.1 parts by weight of solvent mixed with 1 part, 1.5 parts by weight of glass frit (Te-Bi-Li system), 0.3 parts by weight of magnesium stearate, and oleic acid (Wako Pure Chemicals Co., Ltd.) as a dispersant. After mixing (preliminarily kneading) 0.5 parts by weight with a self-revolving vacuum stirring and deaerator (Shinky Co., Ltd., Aritori Kentaro Co., Ltd.) By kneading by EXAKT80S) manufactured by Herman Inc., was obtained (as a finger electrode paste) conductive paste C.

  Next, a silicon wafer (manufactured by E & M Co., Ltd., 100Ω / □, 6-inch single crystal) is prepared, and the above conductive paste is applied to the back surface of the silicon wafer by a screen printer (MT-320T manufactured by Microtech Co., Ltd.). B was printed in the shape of three bus bar electrodes having a width of 1.3 mm, and dried by heating at 200 ° C. for 10 minutes with a hot air dryer. Thereafter, aluminum paste (Alsolar 14-7021 manufactured by Toyo Aluminum Co., Ltd.) is printed on the portion other than the portion where the conductive paste B is printed on the back surface of the silicon wafer, and then heated at 200 ° C. for 10 minutes by a hot air dryer. And dried. Thereafter, the conductive paste C is printed on the shape of 100 finger electrodes having a width of 50 μm by a screen printer (MT-320T manufactured by Microtech Co., Ltd.) on the surface of the silicon wafer, and then 200 by a hot air dryer. Heated at 10 ° C for 10 minutes to dry, fired at a peak temperature of 820 ° C for 21 seconds in-out in a fast firing IR furnace (fast firing test 4-chamber furnace manufactured by NGK Co., Ltd.), and a bus bar on the back side of the silicon wafer An electrode and a surface finger electrode were formed. Then, after printing said electroconductive paste A in the shape of three bus-bar electrodes with a width of 1.3 mm by a screen printer (MT-320T manufactured by Microtech Co., Ltd.) on the surface of a silicon wafer, a hot air dryer After heating and drying at 150 ° C. for 10 minutes, the substrate was heated and cured at 200 ° C. for 40 minutes to form a bus bar electrode on the surface of the silicon wafer.

  After applying the flux to the bus bar electrodes on the front and back of the solar cell thus produced, the solar cell was placed on a hot plate at 50 ° C., and a size of 0.2 mm × 1.5 mm × 176 mm was formed thereon. Place the interconnector material (SSA-SPS manufactured by Hitachi Metals, Ltd.) and solder on both sides of the solar cell by tracing from above at a speed of about 10 mm / s while pressing the soldering iron heated to 380 ° C. As a result, a cell with an interconnector was obtained. Then, from the front side, cover glass, EVA sheet (Ever film), cycloolefin copolymer (COC) film (Topas Advanced Polymers GmbH, TOPAS (registered trademark), thickness 75 μm), EVA sheet, cell with interconnector Then, the EVA sheet and the back sheet were laminated in this order, and this laminate was pressed by a vacuum laminator to obtain a solar cell module. When this solar cell module was irradiated with pseudo-sunlight using a solar simulator and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF were determined, the maximum output Pmax was 4.7 W and the open circuit voltage Voc was 0.8. 6V, short circuit current Isc was 10.0 A, and fill factor FF was 71%.

  Moreover, as a PID test of this solar cell module, using a PID test apparatus (manufactured by ESPEC Corporation), the solar cell module is placed in a chamber having a temperature of 85 ° C. and a humidity of 85%, and a voltage of −000 V is applied for 1000 hours. Then, an accelerated deterioration test was conducted. Thereafter, the solar cell module taken out from the PID test apparatus was irradiated with simulated sunlight by a solar simulator, and the maximum output Pmax, the open circuit voltage Voc, the short-circuit current Isc, and the fill factor FF were obtained. The maximum output Pmax was 4.7 W. The open circuit voltage Voc was 0.6 V, the short circuit current Isc was 10.0 A, the fill factor FF was 71%, and it was confirmed that the solar cell characteristics were not deteriorated at all compared to before the PID test.

[Comparative Example 7]
In the same manner as in Example 5 except that a bisphenol F type epoxy resin (EP4901E manufactured by ADEKA Co., Ltd.) shown in Chemical Formula 2 was used instead of the epoxy resin having a naphthalene skeleton, the conductive (as a bus bar electrode paste) Sex paste A was obtained. Except for using this conductive paste A, an attempt was made to produce a solar cell module by the same method as in Example 5. However, the interconnector and the bus bar were not adhered, and the solar cell module could not be produced. .

[Example 6]
Cover glass, EVA sheet, COC film (Topas Advanced Polymers GmbH, TOPAS (registered trademark), thickness 75 μm), EPDM rubber, interconnector cell, EPDM rubber (transparent, thickness 300 μm) A solar cell module was obtained in the same manner as in Example 5 except that the back sheets were laminated in this order. When this solar cell module was irradiated with pseudo-sunlight using a solar simulator and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF were determined, the maximum output Pmax was 4.7 W and the open circuit voltage Voc was 0.8. 6V, the short circuit current Isc was 11.0 A, and the fill factor FF was 71%. In addition, after performing the same PID test as in Example 5 on this solar cell module, the solar cell module was irradiated with pseudo sunlight by a solar simulator, and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF The maximum output Pmax is 4.9 W, the open-circuit voltage Voc is 0.6 V, the short-circuit current Isc is 10.0 A, the fill factor FF is 70%, and the maximum output is increased, so the PID test It was confirmed that the solar cell characteristics were not deteriorated at all compared to before.

[Comparative Example 8]
A solar cell module was obtained by the same method as in Example 5 except that the laminated body was laminated in the order of the cover glass, the EVA sheet, the cell with an interconnector, the EVA sheet, and the back sheet in this order. . When this solar cell module was irradiated with pseudo-sunlight using a solar simulator and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF were determined, the maximum output Pmax was 4.7 W and the open circuit voltage Voc was 0.8. 6V, the short circuit current Isc was 11.0 A, and the fill factor FF was 71%. When this solar cell module was subjected to the same PID test as in Example 5, delamination occurred between the cell with the interconnector and the EVA sheet after 265 hours, and the maximum output after 1000 hours Etc. could not be measured. When this comparative example is compared with Examples 5 and 6, when using a conductive paste containing the silver-coated copper powder of Example 1 and an epoxy resin having a naphthalene skeleton, a solar cell module is produced. It can be seen that it is better to laminate a COC film between the EVA sheet on the cover glass side and the cell with the interconnector.

  Also, a bus bar electrode (conductive paste containing silver-coated copper powder of Example 1 and an epoxy resin having a naphthalene skeleton) formed on the surface side (cover glass side) of the cell with an interconnector of the solar cell module after the PID test About the cross section of the bus bar electrode formed by A), using an Auger electron spectroscopic analyzer (FE-AES) (JAMP-9500F manufactured by JEOL Ltd.), the diameter of the analysis area is 1 μm, and silver-coated copper powder When the qualitative analysis of the center part of the cross section of the copper particles was performed, oxygen was detected. Moreover, the solar cell module produced in Example 5 (the same solar as Comparative Example 8 except that the EVA sheet between the cover glass and the interconnector-attached cell was replaced with an EVA sheet, a cycloolefin copolymer (COC) film, and an EVA sheet). The same qualitative analysis was performed on the battery module), and oxygen was not detected. From these results, it can be seen that the solar cell module produced in Example 5 does not detect oxygen even after the PID test, and has higher oxidation resistance by combining an epoxy resin having a naphthalene skeleton and a COC film. . The SEM images of the cross sections of the bus bar electrodes formed on the surface side (cover glass side) of the cell with the interconnector of the solar cell module produced in this comparative example and Example 5 are shown in FIGS. 1 and 2, respectively.

  Moreover, about the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module after a PID test, mapping analysis using said Auger electron spectroscopy analyzer (FE-AES) As a result, oxygen was observed in substantially the entire copper particles, and the presence of silver covering copper could hardly be confirmed. Moreover, about the solar cell module produced in Example 5, when the same mapping analysis was performed, silver was detected on the surface of a copper particle, and it exists in the state of silver covering copper powder even after a PID test. Was confirmed. From these results, it can be seen that the solar cell module produced in Example 5 can maintain the state of the silver-coated copper powder even after the PID test by combining the epoxy resin having a naphthalene skeleton and the COC film. In addition, the Ag map image and Cu map image by the mapping analysis of the cross section of the bus-bar electrode formed in the surface side (cover glass side) of the cell with an interconnector of the solar cell module produced in Example 5 are respectively FIG. 3 and FIG. Shown in

[Example 7]
89 parts by weight of silver powder having an average primary particle size of 0.8 μm (AG-2-1C manufactured by DOWA Electronics Co., Ltd.), 4 parts by weight of epoxy resin, 0.2 parts by weight of curing agent, 2 parts by weight of urethane resin, As a solvent, 0.4 part by weight of butyl carbitol acetate (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1 part by weight of oleic acid as a dispersing agent, a self-revolving vacuum stirring deaerator (manufactured by Shinky Corporation) After mixing (preliminary kneading) by Awatori Netaro, the conductive paste D was obtained by kneading with three rolls (EXAKT80S manufactured by Otto Herman).

  Next, a heterojunction type silicon wafer is prepared, and the conductive paste D is printed on the entire back surface of the silicon wafer by a screen printer (MT-320T manufactured by Microtech Co., Ltd.). Was heated at 150 ° C. for 10 minutes and dried, and then heated at 200 ° C. for 30 minutes to be cured. Thereafter, the conductive paste D is printed on the shape of 100 finger electrodes having a width of 50 μm by a screen printer (MT-320T manufactured by Microtech Co., Ltd.) on the surface of the silicon wafer, and then 150 by a hot air dryer. After drying by heating at 10 ° C. for 10 minutes, it was cured by heating at 200 ° C. for 30 minutes. Thereafter, the conductive paste A similar to that of Example 5 was applied to the surface of the silicon wafer by a screen printer (MT-320T manufactured by Microtech Co., Ltd.) with three finger bars having a shape of 100 finger electrodes and a width of 1.3 mm. After printing in the shape which matched the electrode shape, it heated and dried at 150 degreeC with the hot air type dryer for 10 minutes, Then, it heated at 200 degreeC for 30 minutes, and was hardened.

  A solar cell module was obtained in the same manner as in Example 5 using the solar cell thus produced. When this solar cell module was irradiated with pseudo sunlight by a solar simulator and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF were determined, the maximum output Pmax was 5.3 W and the open circuit voltage Voc was 0. 7V, the short circuit current Isc was 11.0 A, and the fill factor FF was 71%. In addition, after performing the same PID test as in Example 5 on this solar cell module, the solar cell module was irradiated with pseudo sunlight by a solar simulator, and the maximum output Pmax, the open circuit voltage Voc, the short circuit current Isc, and the fill factor FF The maximum output Pmax is 4.7 W, the open circuit voltage Voc is 0.7 V, the short circuit current Isc is 10.0 A, the fill factor FF is 67%, the output deterioration rate is only 11%, and it is used for a long time. It was confirmed that it could withstand

  The conductive paste according to the present invention can be used for the production of electronic parts such as conductor patterns of circuit boards, electrodes of boards such as solar cells, and circuits.

Claims (15)

Forming a silver-coated copper powder surfaces of the copper powder is covered with a silver layer, a including conductive paste and an epoxy resin having a naphthalene skeleton, an electrode on the surface of the substrate by curing after application to the substrate The manufacturing method of the electrode for solar cells characterized by the above-mentioned. The method for manufacturing an electrode for a solar cell according to claim 1, wherein the conductive paste contains a solvent. The method for manufacturing an electrode for a solar cell according to claim 1, wherein the conductive paste contains a curing agent. The said hardening | curing agent is at least one of imidazole and a boron trifluoride amine type hardening | curing agent, The manufacturing method of the electrode for solar cells of Claim 3 characterized by the above-mentioned. The method for producing an electrode for a solar cell according to any one of claims 1 to 4, wherein the amount of silver with respect to the silver-coated copper powder is 5% by mass or more. 6. The volume-based cumulative 50% particle diameter (D ₅₀ diameter) measured by the laser diffraction particle size distribution device of the copper powder is 0.1 to ₁₅ μm, 6. Manufacturing method of solar cell electrode . The method for producing an electrode for a solar cell according to any one of claims 1 to 6, wherein the amount of the silver-coated copper powder in the conductive paste is 50 to 90% by mass. A silver-coated copper powder surfaces of the copper powder is covered with a silver layer, a conductive paste containing an epoxy resin having a naphthalene skeleton, an electrode is formed on the surface of the substrate is cured after application to the substrate, the electrode A method of manufacturing a solar cell module, comprising: soldering an interconnector to the interconnector-attached cell having the interconnector soldered to the electrode; and laminating a cover glass via a polyolefin film. The method for manufacturing a solar cell module according to claim 8, wherein the conductive paste contains a solvent. The method for manufacturing a solar cell module according to claim 8 or 9, wherein the conductive paste contains a curing agent. The method for producing a solar cell module according to claim 10, wherein the curing agent is at least one of imidazole and boron trifluoride amine curing agent. The method for producing a solar cell module according to any one of claims 8 to 11, wherein the amount of silver with respect to the silver-coated copper powder is 5 mass% or more. Volumetric cumulative 50% particle diameter (D) measured with a laser diffraction particle size distribution device of copper powder ₅₀ The method for manufacturing a solar cell module according to claim 8, wherein the diameter is 0.1 to 15 μm. The method of manufacturing a solar cell module according to any one of claims 8 to 13, wherein the amount of the silver-coated copper powder in the conductive paste is 50 to 90 mass%. A polyolefin film between a cover glass and a cell with an interconnector having an interconnector soldered to an electrode containing silver-coated copper powder coated with a silver layer on the surface of the copper powder and an epoxy resin having a naphthalene skeleton Are laminated | stacked, The solar cell module characterized by the above-mentioned.

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