JP7021389B1 - Thermosetting conductive paste composition and solar cell, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting conductive paste composition capable of realizing good fine line drawing property while avoiding a great influence on the performance of an electronic device or an electronic component. SOLUTION: The (A) resin component of a thermosetting conductive paste composition contains at least one of an epoxy resin and a urethane resin, and the (C) silicone oil component is at least one of a straight silicone oil and a modified silicone oil. The number average molecular weight is in the range of 1 × 103 to 1 × 105. (B) When the content of the resin component is Z by mass and the weighted average value of the number average molecular weight of the resin constituting the resin component is WMn with respect to 100 parts by mass of the conductive powder. , The condition of the following formula (1) is satisfied, and the content of the silicone oil component (C) is in the range of 0.1 to 2 parts by mass. WMn x Z2 = 5 x 103 to 3 x 105 ... (1) [Selection diagram] None

Description

The present invention relates to a thermosetting conductive paste composition and a solar cell, and a solar cell module. More specifically, the present invention provides excellent conductivity by heat-curing a coating film formed by printing on a substrate. Using a thermosetting conductive paste composition capable of forming an electrode or an electric wiring to have, a solar cell in which at least a current collecting electrode is formed by using this conductive paste composition, and the solar cell. Concerning with the configured solar cell module.

Conventionally, in the field of manufacturing electronic devices or electronic components, a technique using a conductive paste composition as one of a methods for forming electrodes or electrical wiring (wiring) on a substrate such as a film, a substrate, or an electronic component. It has been known. Such a conductive paste composition includes a heat-curable type containing a conductive powder (conductive particles) and a thermosetting resin.

A typical technical field for forming an electrode, wiring, or the like using a thermosetting conductive paste is a solar cell. For example, in a solar cell having an amorphous silicon layer, a thermosetting conductive paste is used for forming a current collecting electrode such as a finger electrode or a bus bar electrode. Generally, the collector electrode is formed by printing a heat-curable conductive paste on the surface of a solar cell by a printing method such as screen printing.

In order to increase the amount of power generation of the solar cell, it is typical to increase the light receiving area. Since the current collector electrode is formed on the light receiving surface side of the solar cell, it is required to make the line width of the current collector electrode as thin as possible (fine line). Therefore, the thermosetting conductive paste is required to have physical properties that enable the formation of a finer line pattern (realizing fine line drawability) at the time of printing.

For the purpose of forming a finer line printed pattern, the applicant of the present application has proposed, for example, a heat-curable conductive paste composition disclosed in Patent Document 1 or Patent Document 2. In the thermosetting conductive paste disclosed in Patent Document 1, the line width in the printed pattern is reduced by setting the storage elastic modulus measured by the rheometer in the range of 100 Pa to 400 Pa. Further, in the thermosetting conductive paste disclosed in Patent Document 2, the line width thickening in the print pattern is reduced by containing a solvent for which the solubility parameter is set.

Japanese Unexamined Patent Publication No. 2013-114736 Japanese Unexamined Patent Publication No. 2013-114837

As disclosed in Patent Document 1 or Patent Document 2, from the viewpoint of optimizing the fine line drawing property of the thermosetting conductive paste composition, it is conceivable to set the physical properties or study the contained components. Here, if an attempt is made to simply optimize the fine line drawing property by setting the physical properties or examining the contained components, the resistance value of the formed electrode or wiring may be affected, or further, the electron provided with the electrode or wiring may be affected. It has become clear that the performance of equipment or electronic components may be affected.

In particular, when an electronic device or electronic component is a solar cell or a solar cell module, even if the current collecting electrode can be made into a thin wire, it will be impractical if its performance is affected. Since a solar cell or a solar cell module is generally installed outdoors, it is necessary to assume that it will be used in a harsher environment than ordinary electronic devices or electronic components. Therefore, in applications for forming a current collecting electrode of a solar cell or a solar cell module, it is required that the thermosetting conductive paste composition realizes good fine line drawing property without significantly affecting the performance. Be done.

The present invention has been made to solve such a problem, and is a thermosetting conductive type capable of realizing good fine line drawing property while avoiding a large influence on the performance of an electronic device or an electronic component. It is an object of the present invention to provide a paste composition.

The thermosetting conductive paste composition according to the present invention contains (A) a resin component, (B) a conductive powder, and (C) a silicone oil component in order to solve the above-mentioned problems. The resin component (A) contains at least one of an epoxy resin and a urethane resin, and the content of the resin component (A) with respect to 100 parts by mass of the conductive powder (B) is Z parts by mass. When the weighted average value of the number average molecular weight of the resin constituting the resin component is WMn, the condition of the following formula (1) is satisfied.
WMn x Z ² = 5 x 10 ³ to 3 x 10 ⁵ ... (1)
The (C) silicone oil component is at least one of a straight silicone oil and a modified silicone oil, and the number average molecular weight thereof is in the range of 1 × ^{10 3} to 1 × 105, and the (B) conductivity is described. The content of the silicone oil component (C) with respect to 100 parts by mass of the powder is in the range of 0.1 to 2.4 parts by mass.

According to the above configuration, the resin component (A) and the silicone oil component (C) are contained based on the mass of the conductive powder (B), and the resin component (A) and the silicone oil component (C) are contained. When the number average molecular weight satisfies the above condition, it is possible to realize good fine line drawing property while avoiding a large influence on the performance of the electronic device or the electronic component. In particular, in an electronic device or electronic component in which an electrode, wiring, or the like is formed by the thermosetting conductive paste composition having the above configuration, it becomes possible to realize good moisture resistance, and the electronic device or electronic component has long-term reliability. Sex can be realized.

In the thermosetting conductive paste composition having the above constitution, when at least one of the epoxy resin and the urethane resin in the resin component (A) is used as the basic resin component, the resin component (A) is further added to the basic resin. A resin other than the components may be contained, and the total content of the basic resin component in the (A) resin component may be 70% by mass or more of the total amount of the (A) resin component.

Further, in the thermosetting conductive paste composition having the above structure, the conductive powder (B) may be a silver powder or a silver-containing powder.

Further, the solar cell according to the present disclosure may be configured to include a current collecting electrode formed of the thermosetting conductive paste composition having the above-mentioned structure.

The solar cell having the above configuration may further include a transparent conductive layer which is a base layer of the current collector electrode.

Further, the solar cell module according to the present disclosure may have a configuration including the solar cell having the above configuration.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a thermosetting conductive paste composition capable of achieving good fine line drawing property while avoiding a large influence on the performance of an electronic device or an electronic component by the above configuration. It plays the effect.

It is sectional drawing which shows the schematic structure of the solar cell which is an example of the electronic device or the electronic component manufactured (manufactured) by the Example of this invention. It is sectional drawing which shows the schematic structure of the solar cell module manufactured (manufactured) using the solar cell shown in FIG. 1.

Hereinafter, typical embodiments of the present disclosure will be specifically described. The thermosetting conductive paste composition according to the present disclosure contains (A) a resin component, (B) a conductive powder, and (C) a silicone oil component. Of these components (A) to (C), the resin component (A) contains at least one of the epoxy resin and the urethane resin (epoxy resin and / or urethane resin). Further, among the components (A) to (C), the (C) silicone oil component is at least one of a straight silicone oil and a modified silicone oil (straight silicone oil and / or a modified silicone oil).

In the thermosetting conductive paste composition according to the present disclosure, the molecular weights of the (A) resin component and (C) silicone oil component satisfy predetermined conditions, and the content (blending amount) of these components is determined. (B) It is set based on the content (blending amount) of the conductive powder. In the following description, the thermosetting conductive paste composition according to the present disclosure is simply abbreviated as "conductive paste composition".

Regarding the (A) resin component of the conductive paste composition according to the present disclosure, the content of the (A) resin component with respect to (B) 100 parts by mass of the conductive powder is set to Z parts by mass (hereinafter, "content Z" as appropriate). (A), (A) When the weighted average value of the number average molecular weight of the resin constituting the resin component is WMn (hereinafter, abbreviated as "molecular weight average value WMn" as appropriate), the content Z and the molecular weight average value are used. WMn satisfies the condition of the following formula (1).

WMn x Z ² = 5 x 10 ³ to 3 x 10 ⁵ ... (1)
Regarding the (C) silicone oil component of the conductive paste composition according to the present disclosure, the number average molecular weight of the (C) silicone oil component is in the range of 1 × ^{10 3} to 1 × 105, and (B). The content of the (C) silicone oil component with respect to 100 parts by mass of the conductive powder is in the range of 0.1 to 2.4 parts by mass.

[(A) Resin component]
The epoxy resin used as the (A) resin component of the conductive paste composition according to the present disclosure is not particularly limited as long as it is a polyvalent epoxy resin having two or more epoxy rings or epoxy groups in one molecule, and is generally not limited. What is used can be used.

Specific examples thereof include a glycidyl type epoxy resin, an alicyclic epoxy resin such as dicyclopentadiene epoxide, and an aliphatic epoxy resin such as butadiene dimer epoxide.

Examples of the glycidyl-type epoxy resin include epichlorohydrin or 2-methylepicrolhydrin and novolak compounds such as phenol novolak and cresol novolak; polyhydric phenols such as bisphenol A (BPA), hydrogenated bisphenol A, bisphenol F, bisphenol AD and resorcin. Polyalcophilic compounds; polyhydric alcohol compounds such as ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, triethylene glycol, polypropylene glycol; polyamino compounds such as ethylenediamine, triethylenetetramine, aniline; or adipic acid, Examples thereof include those obtained by reacting with polyvalent carboxyl compounds such as phthalic acid and isophthalic acid; and the like.

Only one of these epoxy resins may be used as the (A) resin component, or two or more of these epoxy resins may be used in combination as the (A) resin component. In the examples described later, commercially available polyhydric alcohol-based and polyhydric phenol-based glycidyl-type epoxy resins shown in the abbreviations E-1 to E-7 are used (see Table 1).

The epoxy equivalent of the epoxy resin in the present disclosure is not particularly limited, but can be typically in the range of 100 to 1000, and can be typically in the range of 100 to 400. Although it depends on various conditions, if the epoxy equivalent is less than 100, the heat resistance or durability of the cured film formed of the obtained conductive paste composition may be insufficient. On the other hand, if the epoxy equivalent exceeds 1000, the thixophilicity of the obtained conductive paste composition may decrease, depending on various conditions.

Examples of the urethane resin used as the (A) resin component of the conductive paste composition according to the present disclosure include those in which the isocyanate group of a known polyisocyanate compound is blocked (blocked polyisocyanate compound).

Specific examples of the polyisocyanate compound used include phenylenediocyanate, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate, polyaryl polyisocyanate, trizine diisoanate, and xyli. Aromatic isocyanate compounds such as range isosoane and naphthalin diisosoanate; ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, dicyclohexyl An aliphatic polyisocyanate compound such as methanediisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, octamethylene diisocyanate, trimethylhexamethylene diisocyanate; urethane group, carbodiimide group, alohanate group, urea group of these polyisocyanate compounds. , Biuret group, uretdione group, uretoimine group, isocyanurate group or oxazolidone group; isocyanurate compound which is a cyclized trimer of these polyisocyanate compounds (may be classified as isocyanurate modified product); Etc., but are not particularly limited.

Among these polyisocyanate compounds, for example, those containing polymethylenepolyphenylpolyisocyanate having three or more nuclei in its components can be used. Further, a terminal isocyanate group-containing compound synthesized by reacting polyisocyanate and a polyol by a known method can also be used as the urethane resin in the present disclosure. The polyol in this case is not particularly limited, but general polyether polyols, polyester polyols, polycarbonate polyols and the like can be preferably used.

Among these polyols, polyether polyols (or polyalkylene polyols) include, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, bisphenol A, and the like. Examples thereof include polyhydric alcohols or phenol compounds such as hydrogenated bisphenol A, glycerin, trimethylolpropane, or pentaerythritol, to which ethylenedioxide, propylene oxide, or butylene oxide is added.

Examples of polyester polyols include polyvalent values such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and trimethylolpropane. Examples thereof include those obtained by condensing alcohol with polybasic acids such as malonic acid, succinic acid, adipic acid, phthalic acid, and terephthalic acid.

Examples of polycarbonate polyols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and bisphenol. Examples thereof include those obtained by reacting a polyhydric alcohol such as A or a phenol compound with dimethyl carbonate, diphenyl carbonate, or even phosgen.

Further, the blocking agent for the polyisocyanate compound is not particularly limited, but specifically, for example, imidazole, 2-methylimidazole, pyrazole, 3-methylpyrazole and 3,5-dimethylpyrazole, 1,2,4-. Oximes such as triazole; phenols such as phenol, cresol, ethylphenol, n-propylphenol, isopropylphenol, n-butylphenol, octylphenol, nonylphenol, xylenol, diisopropylphenol, di-t-butylphenol, xylenol, chlorophenol, ethylphenol and the like. Kind: Oximes such as formaldehyde, acetoaldoxime, acetooxime, methylethylketone oxime (MEK oxime), methylisobutylketone oxime (MIBK oxime), diacetylmonooxime, cyclohexanone oxime; and the like.

Each of the above-mentioned compounds used as the urethane resin in the present disclosure may be used alone or in combination of two or more. Further, such a urethane resin may be used as only one type (A) resin component, or may be used as a (A) resin component in combination of two or more types.

In the examples described later, a urethane resin in which hexamethylene diisocyanate (HDI) or HDI isocyanurate (modified isocyanurate) is blocked with methyl ethyl ketone oxime (urethane resin of abbreviation U-1 or U-2 in Table 1 described later), or , HDI isocyanurate-type polyisocyanate is reacted with a polypropylene polyol (a polyether polyol in which propylene oxide is added to propylene glycol) and blocked with methyl ethyl ketone oxime, and a urethane resin (abbreviated as U-3 urethane resin) is used.

As the resin component (A), as described above, at least one of an epoxy resin and a urethane resin may be used. Therefore, in the conductive paste composition according to the present disclosure, the resin component (A) may be composed of only one kind of epoxy resin, or may be made up of only two or more kinds of epoxy resins. It may be composed of only one type of urethane resin, may be composed of only two or more types of urethane resin, or may be composed of one or more types of epoxy resin and one or more types of urethane resin. May be good.

Further, the resin component (A) may contain a resin other than the epoxy resin or the urethane resin. In the present disclosure, when at least one of the epoxy resin and the urethane resin in the (A) resin component is used as the basic resin component, the (A) resin component may further contain a resin other than the basic resin component. good. At this time, the content of the basic resin component in the (A) resin component may be 70% by mass or more of the total amount of the (A) resin component.

That is, in the present disclosure, the resin component (A) contains 70% by mass or more of the total amount of the epoxy resin or the urethane resin, or the epoxy resin and the urethane resin, and the other resin is less than 30% by mass. It may be contained. By allowing the other resin to be contained as the resin component (A) in this way, it is possible to impart physical characteristics or properties derived from the other resin to the conductive paste composition according to the present disclosure.

The other resin that can be used as the (A) resin component is not particularly limited, and examples thereof include butyral resin, polyester resin, and acrylic resin.

In the present disclosure, the molecular weight of the resin constituting the resin component (A) is not particularly limited, but in the present disclosure, it is necessary to satisfy the numerical range specified by the condition of the above-mentioned formula (1). As described above, when the weighted average value of the number average molecular weight of the resin constituting the resin component is the molecular weight average value WMn, the above formula (1) is the molecular weight average value WMn of the resin component (A). The multiplication value of the content Z with the square is set to be within the range of 5 × 10 ³ to 3 × 10 ⁵ .

Therefore, when the resin component (A) is composed of one kind of resin (one kind of epoxy resin or urethane resin), the number average molecular weight of the resin itself corresponds to the mean molecular weight value WMn, and this molecular weight. It is necessary to satisfy the numerical range specified by the condition of the above formula (1) between the average value WMn and the content Z. Further, (A) when the resin component is composed of a plurality of types of resins (two or more types of epoxy resins, two or more types of urethane resins, or a combination of one or more types of epoxy resins and one or more types of urethane resins). The weighted average value of the number average molecular weights of these plurality of types of resins is calculated to obtain the molecular weight average value WMn, and the above formula (1) is used between the molecular weight average value WMn and the content Z of the resin component (A). ) Must satisfy the numerical range specified by the condition.

The average molecular weight value WMn may be calculated by a general calculation formula. Specifically, for example, assuming a plurality of types of resin 1, resin 2, ..., Resin n, the number average molecular weights of each of these resins 1 to resin n are set to x1, x2, ..., Xn, and (A). When the mass ratio of these resins 1 to n in the resin component is y1, y2, ..., Yn, the molecular weight average value WMn can be calculated by the following formula. When other resins are used in combination with the basic resin components (epoxy resin and urethane resin), the other resins are also included in the calculation of the molecular weight average value WMn.
WMn = (x1 x y1 + x2 x y2 + ... + xn x yn) / (y1 + y2 + ... + yn)

[(B) Conductive powder]
The conductive powder (B) in the conductive paste composition according to the present disclosure is not particularly limited, and may be powder or particles of a known conductive material. Specific examples thereof include silver powder, copper powder, gold powder, palladium powder, nickel powder, aluminum powder, lead powder, carbon powder and the like. (B) When the conductive powder is a metal powder, an alloy powder is also included. For example, silver powder contains silver alloy powder, copper powder contains copper alloy powder, and gold powder contains gold alloy powder. Further, (B) the conductive powder also includes a powder coated with a conductive material. For example, a powder obtained by coating the surface of a powder of a cheaper material (which may or may not be a conductive material) with a metal such as silver, copper, or gold can also be used as (B) the conductive powder. ..

Among these, a conductive powder containing at least silver, that is, a "silver-containing powder" is preferably used. Specific silver-containing powders include silver powder substantially composed of silver, silver-coated powder obtained by coating the surface of a powder (main body powder) composed of a material other than silver with silver, and an alloy containing silver (silver). Examples include silver alloy powder composed of alloy). Among these, silver powder and silver-coated powder are particularly preferably used.

The silver powder is a powder composed only of silver, but it goes without saying that it may contain known unavoidable impurities. Further, even silver alloy powder having a purity recognized as "silver" in various known standards can be treated as silver powder in the present disclosure.

The specific composition of the silver-coated powder is not particularly limited, and the material of the main body powder composed of a material other than silver may be a metal or a material other than the metal. Examples of materials other than metal include known resin materials, known ceramic materials, and glass. When the main body powder is a resin material, it has heat resistance enough to maintain the powder shape (particle shape) even at the heating temperature at which the conductive paste composition according to the present disclosure is cured. good.

Examples of the silver-coated powder in which the main body powder is a metal, that is, the silver-coated metal powder, include silver-coated copper powder, silver-coated copper alloy powder, silver-coated nickel powder, silver-coated aluminum powder, and the like, but are particularly limited. Not done. Examples of the silver-coated powder in which the main body powder is a resin, that is, the silver-coated resin powder, such as silver-coated polyimide resin powder, are not particularly limited. Examples of the silver-coated powder in which the main body powder is a ceramic material, that is, the silver-coated ceramic powder, such as silver-coated alumina powder, are not particularly limited.

When the silver-containing powder is a silver-coated powder, the amount of silver coated on the surface of the main body powder, that is, the amount of silver-coated powder is not particularly limited and can be appropriately set according to various conditions. The amount of silver coating can be increased or decreased according to the volume resistivity or the like required according to the use of the conductive paste composition according to the present disclosure (use of the cured product). Alternatively, the amount of silver coating can be increased or decreased depending on the material (conductivity) of the main body powder. The silver-coated amount can be expressed by the ratio of the weight of the coated silver to the total mass of the silver-coated powder (mass ratio, for example, percentage (mass%) or the like).

(B) The specific shape of the conductive powder is not particularly limited, and examples thereof include spherical powder and flake-like powder. Flake-like means that even if it is partially uneven and deformed, it includes a flat plate or a thin rectangular parallelepiped when viewed as a whole. Flakes also include flaky or scaly shapes. The term "spherical" means that even if it is partially uneven and deformed, it includes a three-dimensional shape that is closer to a cube than a rectangular parallelepiped when viewed as a whole, and may be substantially spherical. , Even if it is an ellipsoidal sphere, it may be a granular shape that cannot be said to be flaky.

In the present disclosure, only the spherical powder may be used, only the flake-shaped powder may be used, or these may be used in combination. The method for producing the spherical powder and the flake-shaped powder is not particularly limited, and a known method can be used. Here, the flake-like powder is often more costly than producing a normal spherical powder due to its production process. Therefore, it may be possible to suppress the increase in cost by using the flake-like powder and the spherical powder in combination.

When a spherical powder and a flake-shaped powder are mixed and used as the silver-containing powder, the total of both is 100 parts by mass, the flake-shaped powder is in the range of 20 to 80 parts by mass, and the spherical powder is 80 to 80 parts by mass. The flake-like powder may be in the range of 30 to 70 parts by mass, the spherical powder may be in the range of 70 to 30 parts by mass, and the flake-like powder may be in the range of 40 to 60 parts by mass. It is in the range of parts by mass, and the spherical powder may be in the range of 60 to 40 parts by mass. When either the flake-like powder or the spherical powder exceeds 80 parts by mass or is less than 20 parts by mass, or when the advantages of using both of them together (such as achieving better conductivity) cannot be sufficiently obtained. There is.

(B) When the conductive powder is spherical or flaky, the specific physical quantity thereof is not particularly limited. Examples of the physical quantity of the silver-containing powder include average particle size D50, BET specific surface area, tap density, aspect ratio, degree of cohesion (average particle size D50 / average particle size DSEM) and the like.

In the present embodiment, the average particle size D50 of the powder is a particle size distribution of the powder by a laser diffraction method using a known measuring device (for example, Nanotrac (registered trademark) manufactured by Microtrac Incorporated). The particle size may be a cumulative 50% by mass in the measured case. The average particle size DMEM may be any average particle size of the primary particles obtained from an image observed by a scanning electron microscope. The degree of cohesion may be the one obtained by dividing the average particle size D50 by the average particle size DSME. Various conditions in the specific measurement method or evaluation method of these physical quantities are conditions known in the field of the thermosetting conductive paste composition (for example, the prior patent of the thermosetting conductive paste composition by the applicant of the present application). The terms and conditions described in the publication of the application) may be applied.

The average particle size D50 of the spherical powder may be in the range of 0.1 to 5 μm, may be in the range of 0.5 to 4 μm, or may be in the range of 1 to 3 μm. If the average particle size D50 of the spherical powder is smaller than 0.1 μm, (B) the conductive powder tends to have a high viscosity when kneaded with other components, making it difficult to make a paste. On the other hand, when the average particle size D50 of the spherical powder is larger than 5 μm, the mesh screen used may be clogged or the electrode pattern may be clogged when the electrode pattern or the wiring pattern is printed by screen printing as in the case of the flake-shaped powder. Alternatively, the fine line drawing property of the wiring pattern may be deteriorated.

The average particle size D50 of the flake-like powder may be in the range of 2 to 20 μm, may be in the range of 2 to 12 μm, or may be in the range of 5 to 10 μm. If the average particle size D50 of the flake-like powder is smaller than 2 μm, the resistance at the contact interface between the powders is large and good conductivity may not be realized. On the other hand, if the average particle size D50 of the flake-like powder is larger than 20 μm, the resistance at the contact interface between the powders becomes small, but as described above, the mesh screen may be clogged or the fine line drawing property of the print pattern may be deteriorated. There is.

The BET specific surface area of the spherical powder may be in the range of 0.5 to 1.7 m ² / g, may be in the range of 0.6 to 1.6 m ² / g, and may be in the range of 0.9 to 1. It may be within the range of 6 m ² / g. If the BET specific surface area of the spherical powder is smaller than 0.5 m ² / g, the contact area between the powders may be small and good conductivity may not be realized. On the other hand, if the BET specific surface area of the spherical powder exceeds 1.7 m ² / g, the contact area between the powders becomes large, but the paste viscosity becomes high, so that the filling is high, that is, (B) conductivity in the conductive paste composition. It may not be possible to secure a sufficient content of the sex powder and achieve good conductivity.

The BET specific surface area of the flake-like powder may be in the range of 0.1 to 1 m ² / g, may be in the range of 0.2 to 0.8 m ² / g, and may be in the range of 0.2 to 0.5 m. It may be in the range of ² / g. If the BET specific surface area of the flake-shaped powder is smaller than 0.1 m ² / g, the thickness of the flake-shaped powder becomes large and the powder (particle) shape becomes close to a sphere, so that the contact area between the powders becomes small and good conductivity is obtained. It may not be possible to achieve sex. On the other hand, if the BET specific surface area of the flake-like powder exceeds 1 m ² / g, the contact area between the powders becomes large, but the paste viscosity becomes high. It may not be possible to secure a sufficient powder content and achieve good conductivity.

The tap density of the spherical powder may be in the range of 2 to 5 g / cm ³ , may be in the range of 3 to 5 g / cm ³ , or may be in the range of 3 to 4 g / cm ³ . If the tap density of the spherical powder is less than 2 g / cm ³ , the powder becomes bulky, and it becomes impossible to sufficiently secure the content of the (B) conductive powder in the high filling, that is, the conductive paste composition, and the good conductivity is good. It may not be possible to achieve sex. On the other hand, if the tap density exceeds 5 g / cm ³ , the powder is likely to be excessively dispersed, and (A) the resin component is likely to enter between the (B) conductive powders. The resistance at the contact interface increases, and good conductivity may not be achieved.

The tap density of the flake-like powder may be in the range of 3 to 7 g / cm ³ , may be in the range of 3 to 6 g / cm ³ , and may be in the range of 3.5 to 5.5 g / cm ³ . There may be. If the tap density of the flake-like powder is less than 3 g / cm ³ , the powder becomes bulky, that is, the content of the (B) conductive powder in the highly filled, that is, the conductive paste composition cannot be sufficiently secured, which is good. It may not be possible to achieve conductivity. On the other hand, it is said that it is difficult to industrially obtain a flake-like powder having a tap density of more than 7 g / cm ³ .

The aspect ratio of the flake-like powder may be in the range of 5 to 15, may be in the range of 6 to 12, or may be in the range of 6 to 10. If the aspect ratio of the flake-like powder is less than 5, the contact area between the powders becomes small because the flake formation is not sufficient, and good conductivity may not be realized. On the other hand, if the aspect ratio of the flake-like powder exceeds 15, the contact area between the powders becomes large, but the filling is high, that is, the content of the (B) conductive powder in the conductive paste composition cannot be sufficiently secured. It may not be possible to achieve good conductivity.

The degree of cohesion of the spherical powder (average particle size D50 / average particle size DSEM) may be in the range of 2 to 15, may be in the range of 3 to 11, and may be in the range of 3 to 7.5. You may. If the degree of cohesion is smaller than 2, the powder is likely to be excessively dispersed, and (A) the resin component is likely to enter between the (B) conductive powders, so that (B) the resistance at the contact interface between the conductive powders is high. It becomes large and may not be able to achieve good conductivity. On the other hand, when the degree of cohesion is larger than 15, the powder becomes bulky, and it becomes impossible to sufficiently secure the content of the (B) conductive powder in the high filling, that is, the conductive paste composition, and it is possible that good conductivity cannot be realized. There is sex.

(B) The amount of sodium ion and the amount of potassium ion contained in the conductive powder may be less than 200 ppm, less than 100 ppm, or less than 10 ppm, respectively. If the amount of sodium ion and the amount of potassium ion contained in the silver-containing powder each exceed 200 ppm, there is a risk of affecting the electrical characteristics or electrical connection reliability of the electronic component or electronic device. Therefore, it is preferable that the amount of sodium ion and the amount of potassium ion contained in (B) the conductive powder are as low as possible. Ideally, (B) the conductive powder does not contain any sodium ions and potassium ions, but practically, (B) the amount of sodium ions and potassium ions contained in the conductive powder is high. It is particularly preferable that each is less than 10 ppm.

In the examples described later, as (B) the conductive powder, spherical silver powder, flake-shaped silver powder, and spherical silver-coated copper powder (silver-coated amount 10% by mass) are used, and the average particle size D50, BET specific surface area, and The tap density is optimized. By optimizing the physical quantities of these (B) conductive powders, better conductivity can be realized, but in particular, in the conductive paste composition according to the present disclosure, (A) resin component and (C) silicone oil. By setting the above-mentioned molecular weight and content of the components, a synergistic effect can be expected in terms of achieving good fine line drawing performance, and further, even better long-term reliability in electronic devices or electronic components (described later). Moisture resistance, etc.) can also be achieved.

Regardless of the material or shape of the (B) conductive powder, a surface treatment agent may be attached to the surface of the (B) conductive powder in order to improve the dispersibility. Examples of such a surface treatment agent include at least one selected from the group consisting of fatty acids, fatty acid salts, fatty acid emulsions, fatty acid amides, surfactants, organic metals, compounds having an azole structure and protective colloids. However, it is not particularly limited.

When a silver-containing powder is used as the (B) conductive powder and a conductive powder other than the silver-containing powder is used in combination, the silver-containing powder exceeds at least 10% by mass among all the (B) conductive powders. It may be contained, and may be contained in an amount of 50% by mass or more, 90% by mass or more, or 95% by mass or more. The blending amount when the other conductive powder is used in combination can be appropriately set according to various conditions required for the obtained cured product.

[(C) Silicone oil component]
The (C) silicone oil component in the conductive paste composition according to the present disclosure is at least one of straight silicone oil and modified silicone oil, and the number average molecular weight Mn thereof is within the range of 1 × ^{10 3} to 1 × 105. It should be. The "straight silicone oil" in the present disclosure means unmodified (unmodified) silicone oil.

In the present disclosure, the silicone oil that can be used as the (C) silicone oil component is not particularly limited. Examples of the straight silicone oil include dimethylsilicone oil, methylphenylsilicone oil, diphenylsilicone oil, methylhydrogen silicone oil, cyclic dimethylsiloxane oil and the like.

Examples of the modified silicone oil include monoamine-modified silicone oil, diamine-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carbinol-modified silicone oil, mercapto-modified silicone oil, carboxy-modified silicone oil, and hydrogen-modified silicone. Reactive modified silicone oils such as oils, (meth) acrylic modified silicone oils, phenol modified silicone oils, polyether modified silicone oils, alkoxy modified silicone oils; polyether modified silicone oils, alkyl modified silicone oils, fluorine modified silicone oils; methyl Non-reactive modified silicone oils such as styryl-modified silicone oils, aralkyl-modified silicone oils, fluoroalkyl-modified silicone oils, halogen-modified silicone oils, higher fatty acid ester-modified silicone oils, and higher fatty acid amide-modified silicone oils;

In the modified silicone oil, regardless of whether it is reactive or non-reactive, the position of the introduced functional group may be a side chain, both ends, one end, or a side chain. It may be both ends. Further, in the above example, the case where one kind of functional group is introduced into the modified silicone oil is mentioned, but of course, the modified silicone oil into which a plurality of kinds of functional groups are introduced may be used. For example, in the reactive modified silicone oil, amino polyether modified silicone oil, epoxy / aralkyl modified silicone oil, epoxy / polyether silicone oil and the like can be exemplified, and in the non-reactive modified silicone oil, alkyl aralkyl modified. Examples thereof include silicone oil, polyether, alkyl, and aralkyl-modified silicone oil. When the functional group is an alkyl group, it may be a long-chain alkyl group.

In the examples described later, commercially available dimethyl silicone oil (abbreviation S-1, S-2, S-4, S-5, S-7), methylphenyl silicone oil (abbreviation S-3), both-ended epoxy-modified silicone. Oil (abbreviation S-5) is used (see Table 3).

(C) As described above, the number average molecular weight Mn of the silicone oil used as the silicone oil component may be in the range of 1 × 10 ³ to 1 × 10 ⁵ , but for example, the lower limit is 2 × 10 ³ or more. It may be 3 × 10 ³ or more, or it may be 4 × 10 ³ or more. A particularly preferable lower limit value of 1 × 10 ³ or more can be derived based on the comparison between Examples and Comparative Examples described later.

Further, the upper limit of the number average molecular weight Mn of the silicone oil may be, for example, 9 × 10 ⁴ or less, 8 × 10 ⁴ or less, or 7 × 10 ⁴ or less. .. A particularly preferable upper limit value of 1 × ¹⁰⁵ or less can be derived based on the comparison between Examples and Comparative Examples described later.

As the (C) silicone oil component, one type of silicone oil may be used, but two or more types of silicone oil may be used in combination. When two or more types of silicone oils are used in combination, the number average molecular weight Mn of the (C) silicone oil component is the same as the above-mentioned (A) resin component, and the number of (C) a plurality of silicone oils constituting the silicone oil component. The weighted average value of the average molecular weight may be calculated and within the above range.

[Other ingredients]
The conductive paste composition according to the present disclosure may contain other components in addition to the components (A) to (C). As a typical other component, a curing agent that cures the (A) resin component, which is a thermosetting component, can be mentioned. As described above, as the resin component (A), an epoxy resin or a urethane resin which is a thermosetting resin is used as a basic resin component, and as a curing agent for these resins, imidazoles and Lewis acid containing boron fluoride are used. And their complexes or salts, amine adduct, tertiary amines, dicyandiamides, phenolic resins, acid anhydrides and the like.

Specific examples of the imidazoles include, for example, imidazole, 2-methylimidazole, 2-ethyl-4methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1-benzyl-2-methylimidazole, 2-. Examples thereof include phenyl-4methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole, 1-methylimidazole, 2-ethylimidazole and the like.

Specific examples of Lewis acids containing boron fluoride and their complexes or salts include boron trifluoride ethyl ether, boron trifluoride phenol, boron trifluoride piperidine, boron trifluoride acetate, and trifluoride. Boron trifluoride triethanolamine, boron trifluoride monoethanolamine, boron trifluoride monoethylamine and the like can be mentioned.

Specific examples of the amine adduct include Ajinomoto Fine-Techno Co., Ltd. Amicure series and Fuji Kasei Kogyo Co., Ltd. Fujicure series.

Specific examples of the tertiary amine include dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dimethylbehenylamine, dilaurylmonoethylamine, and methyldideesi. Luamine, Methyldioleylamine, Triallylamine, Triisopropanolamine, Triethylamine, 3- (dibutylamino) propylamine, Tri-n-octylamine, 2,4,6-Trisdimethylaminomethylphenol, Triethanolamine, Methyldiethanolamine, Diazabicycloundecene and the like can be mentioned.

Specific examples of the phenolic resin include JER170 and JER171N manufactured by Mitsubishi Chemical Corporation, MEH-8000H and MEH-8005 manufactured by Meiwa Kasei Co., Ltd.

Specific examples of the acid anhydride include phthalic anhydride, maleic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, trimetic anhydride, pyromellitic anhydride, or Shin Nihon Rika. Examples thereof include Ricacid MH-700 and Ricacid HNA-100 manufactured by Ricacid Co., Ltd.

These curing agents may be used alone or in combination of two or more. In the examples described later, a commercially available imidazole-based curing agent is used.

The amount of these curing agents added is not particularly limited, but for example, if the epoxy resin is used as a reference among the basic resin components, the amount of the curing agent is in the range of 3 to 30 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin. It may be used within the range of 3 to 15 parts by mass, or may be used within the range of 3 to 10 parts by mass.

If the amount of the curing agent added is less than 3 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin, the curing of the resin component (A) becomes insufficient, and good conductivity cannot be realized in the formed electrode or wiring. there is a possibility. On the other hand, if the amount of the curing agent added exceeds 30 parts by mass, the paste viscosity of the conductive paste composition becomes high, which may affect the fine line drawing property. Depending on the implementation status of the present disclosure, the upper limit of the amount of the curing agent added may be "more than" instead of "more than", and the lower limit may be "less than" instead of "less than or equal to".

As another component contained in the conductive paste composition according to the present disclosure, a solvent can be mentioned. This solvent can be added (blended) to adjust the physical characteristics such as the viscosity of the conductive paste composition.

Specific solvents include, for example, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and mono. Glycol ethers such as butyl diglycol, dibutyl diglycol, triethylene glycol dimethyl ether; and acetate esters of these glycol ethers; DBE (dibasic acid ester), 2,2,4-trimethyl-1,3-pentanediol mono Ethers such as isobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 2-ethylhexyl methacrylate; ketones such as cyclohexanone and isophorone; monoterpene alcohols such as tarpineol and hydrogenated tarpineol. And the like; and ethers of these monoterpene alcohols; γ-butyrolactone; limonene; n-methyl-2-pyrrolidone; etc. can be exemplified. These solvents may be used alone or in combination of two or more. In the examples described later, butyl diglycol acetate (acetate ester of monobutyl diglycol) is used for adjusting the viscosity.

The content (blending amount) of the solvent is not particularly limited. As described above (as in Examples described later), for the purpose of adjusting the viscosity of the conductive paste composition according to the present disclosure, for example, 0.1% by mass with respect to the total mass of the conductive paste composition. Although it can be mentioned in the range of about 10% by mass, it may be blended in the range of 0.5% by mass to 5% by mass, or may be blended in an amount outside these ranges.

Other known components other than the curing agent and the solvent include, for example, various known additives such as a dispersant (stabilizer), an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent. Agents can be mentioned, but are not particularly limited.

[Manufacturing method and use of conductive paste composition]
The method for producing the conductive paste composition according to the present disclosure is not particularly limited, and a known method can be preferably used. As a typical example, the above-mentioned components (A) to (C) and, if necessary, other components may be mixed at a predetermined mixing ratio (based on mass) and made into a paste using a known kneading device. .. Examples of the kneading device include, but are not limited to, a three-roll mill and the like.

As described above, the specific composition of the conductive paste composition according to the present disclosure, that is, the blending amount (content) of the components (A) to (C) which are the basic components, is the (B) conductive powder 100. It is set based on the mass part. The content of (C) the silicone oil component with respect to 100 parts by mass of (B) the conductive powder may be in the range of 0.1 to 2.4 parts by mass.

(C) The lower limit of the content of the silicone oil component may be 0.1 part by mass or more, but may be 0.2 part by mass or more, or 0.3 part by mass or more. , 0.4 parts by mass or more, or 0.5 parts by mass or more. Further, the upper limit of the content of the (C) silicone oil component may be 2.4 parts by mass or less, but may be 2.3 parts by mass or less, or 2.2 parts by mass or less. It may be 2.1 parts by mass or less, or may be 2.0 parts by mass or less. These upper limit values or lower limit values can be derived based on the comparison of Examples and Comparative Examples described later. Further, depending on the implementation status of the present disclosure, the upper limit value may be "more than" instead of "greater than or equal to", and the lower limit value may be "less than" instead of "less than or equal to".

Regarding the content of the resin component (A), a suitable content can be derived not from the content alone but from the relational expression with the number average molecular weight of the resin constituting the resin component (A). Specifically, as described above, (A) the content of the resin component is Z mass parts (content Z), and (A) the weighted average value of the number average molecular weights of the resins constituting the resin component is the molecular weight average value. When WMn is used, the content Z and the molecular weight average value WMn satisfy the condition of the following formula (1).

WMn x Z ² = 5 x 10 ³ to 3 x 10 ⁵ ... (1)
The upper limit of the numerical range specified by the condition of the above formula (1), that is, the upper limit of the product of the average molecular weight value WMn and the square of the content Z is 5 × 10 ³ or more, but 5.5 × 10 ³ or more. It may be 6.0 × 10 ³ or more. Further, the lower limit of the numerical range specified by the condition of the above equation (1) is 3 × ^{105 or less, but may be 2 × 105 or less, or may be 1 × 10 5 or less} . .. These upper limit values or lower limit values can be derived based on the comparison of Examples and Comparative Examples described later. Further, depending on the implementation status of the present disclosure, the upper limit value may be "more than" instead of "greater than or equal to", and the lower limit value may be "less than" instead of "less than or equal to".

Further, when the conductive paste composition according to the present disclosure contains other components other than the components (A) to (C), the content thereof is not particularly limited, and the general usage amount of the other components, Alternatively, it may be contained in an amount that does not affect the basic physical properties of the conductive paste composition.

The specific method of using the conductive paste composition according to the present invention is not particularly limited, and a step of applying or printing the conductive paste composition on a substrate with a predetermined conductor pattern (pattern forming step) and a substrate. Any method may be used as long as it includes a step of heating and curing the above conductor pattern (heat curing step). The cured conductor pattern (cured film) becomes the electrodes and wiring formed on the base material.

Examples of the pattern forming target by the conductive paste composition, that is, the base material, include known films, substrates, and other base materials corresponding to the above-mentioned electronic devices or electronic components. The specific material, shape, dimensions, other conditions, etc. of these base materials are not particularly limited, and an appropriate material may be selected according to the type of electronic device or electronic component.

In the present disclosure, a solar cell or a solar cell module can be mentioned as a particularly representative electronic device or electronic component. As illustrated in Examples described later, when the current collecting electrode of a solar cell is formed by using the conductive paste composition according to the present disclosure, it depends on the specific type of the solar cell, but is based on the basic. The material may be a transparent conductive layer (transparent electrode film). A typical transparent conductive layer includes indium tin oxide (ITO), but zinc oxide-based materials, tin oxide-based materials, titanium oxide-based materials, and the like are also known. Since all of these are ceramic materials, their affinity for the conductive paste composition, which is a resin composition, is relatively low.

As a result of diligent studies by the present inventors, as described above, from the viewpoint of optimizing the fine line drawing property of the conductive paste composition, the physical property setting or the contained components were examined. It has been clarified that the fine line drawing property of the sex paste composition can be improved better. However, if good fine line drawability is prioritized, as shown in Examples (Comparative Examples 3 to 5, 9, 10) described later, the line resistance of the electrode or wiring becomes high and the performance of the electronic device or electronic component is affected. It became clear that

In the examples described later, a solar cell and a solar cell module are given as typical examples of electronic devices or electronic components, but even if good fine line drawing can be realized, the line resistance of the collector electrode becomes high and the sun The result is that the cell characteristics of the battery cell are not sufficient (Comparative Examples 3, 4, 9). Alternatively, even if good fine line drawing property, good line resistance, and good cell characteristics can be realized, the result that the moisture resistance of the solar cell module is affected is obtained (Comparative Examples 5 and 10). Even if good results are obtained as a solar cell, the decrease in moisture resistance of the solar cell module including the solar cell means that the long-term reliability of the solar cell module installed and used outdoors is reduced. become.

Based on these results, even if silicone oil can be added to the conductive paste composition to achieve good fine line drawing properties for the electrodes or wiring, the characteristics of the silicone oil allow the base layer (base) of the electrodes or wiring. It is possible that some effect will occur on the adhesion with the material). Therefore, as a result of further studies by the present inventors, (C) the number average molecular weight and the content of the silicone oil component are set within a predetermined range, and the (A) resin component which is the "main component" is (A). B) It was independently found that there is a relationship represented by the above formula (1) between the content (blending amount) based on the conductive powder and the number average molecular weight of the resin.

Therefore, the conductive paste composition according to the present disclosure can be suitably used for forming fine electrodes or wiring in various electronic devices or electronic components, but in particular, the base layer (base material) is transparent. In the case of a ceramic-based material (or an inorganic material-based material) such as a conductive layer (transparent electrode film), even better effects can be exhibited. Therefore, a solar cell in which the base layer of the current collecting electrode formed by the conductive paste composition according to the present disclosure is a transparent conductive layer can be mentioned as a typical electronic device or electronic component of the present disclosure.

Among the above-mentioned examples of the method of using the conductive paste composition, various known conductor pattern forming methods (printing method or coating method) can be used in the pattern forming step, but typically, a mesh screen is used. The screen printing used can be mentioned. Alternatively, a printing method such as a gravure printing method, an offset printing method, an inkjet method, a dispenser method, or a dip method can also be applied.

The physical characteristics of the conductive paste composition according to the present disclosure are not particularly limited, but the viscosity of the conductive paste composition is 75 to 100 Pa · s for convenience during the pattern forming step, especially for the efficiency of screen printing. It can be mentioned within the range. When the viscosity is within this range, the conductor pattern can be suitably formed by screen printing. As described above, the viscosity of the conductive paste composition may be adjusted by adding a solvent.

Among the examples of the method of using the conductive paste composition described above, the heating method or the heating temperature is not particularly limited in the heat curing step, but the heating temperature is preferably in the range of 100 to 250 ° C. If the heating temperature is lower than 100 ° C, the curing of the conductive paste composition may be insufficient, and if it is higher than 250 ° C, (A) the resin component may be decomposed or peeled from the substrate. ..

The conductive paste composition according to the present disclosure can be widely used for forming high-definition electrodes, wiring, and the like, or for adhering electronic components. Specifically, for example, a current collecting electrode of a solar cell; an internal electrode or an external electrode of a chip-type electronic component; RFID (Radio Frequency IDentification), an electromagnetic wave shield, a vibrator adhesive, a membrane switch, a touch panel, electroluminescence, etc. It can be suitably used for applications such as electrodes or wiring or adhesion of parts used in the above.

In particular, in the present disclosure, as a typical application field, as described above, a solar cell provided with a current collecting electrode formed of the conductive paste composition according to the present disclosure can be mentioned, and further, the sun. A solar cell module including a battery cell can be mentioned. Therefore, the present disclosure includes not only conductive paste compositions but also solar cells and solar cell modules.

The specific types or configurations of the solar cell and the solar cell module are not particularly limited. In the present disclosure, in the examples described later, the solar cell schematically shown in FIG. 1 and the solar cell module having the configuration schematically shown in FIG. 2 are used, but the solar cell and the solar cell module according to the present disclosure are used. Is not limited to the configuration shown in FIG. 1 or FIG.

As described above, the thermosetting conductive paste composition according to the present disclosure contains (A) a resin component, (B) a conductive powder, and (C) a silicone oil component, and (A) a resin component. However, at least one of the epoxy resin and the urethane resin, and (B) the content of the (A) resin component with respect to 100 parts by mass of the conductive powder is set to Z parts by mass (content Z), and (A) the resin component is composed. When the weighted average value of the number average molecular weight of the resin to be resin is WMn, the numerical range specified by the condition of the above formula (1) is satisfied, and (C) the silicone oil component is that of straight silicone oil and modified silicone oil. At least one of them has a number average molecular weight in the range of 1 × ^{10 3} to 1 × 105, and (B) the content of the (C) silicone oil component with respect to 100 parts by mass of the conductive powder is 0.1. The configuration is within the range of up to 2.4 parts by mass.

According to such a configuration, the resin component (A) and the silicone oil component (C) are contained based on the mass of the conductive powder (B), and the resin component (A) and the silicone oil (C) are contained. When the number average molecular weight of the components satisfies the above conditions, it is possible to realize good fine line drawing property while avoiding a large influence on the performance of the electronic device or the electronic component. In particular, in an electronic device or electronic component in which an electrode, wiring, or the like is formed by the thermosetting conductive paste composition having the above configuration, it becomes possible to realize good moisture resistance, and the electronic device or electronic component has long-term reliability. Sex can be realized.

The present disclosure will be described in more detail based on Examples and Comparative Examples, but the present disclosure is not limited thereto. Those skilled in the art may make various changes, modifications, and modifications without departing from the scope of the present disclosure.

The evaluation of the manufacturing example of the solar cell and the solar cell module as the electronic device (or the electric power device) in the following Examples or Comparative Examples, the characteristics of the solar cell, and the characteristics of the current collecting electrode is as follows. I went there.

[Manufacturing of solar cells]
The solar cell illustrated in FIG. 1 was produced (manufactured) using the conductive paste composition of Examples or Comparative Examples described later.

The solar cell 10 shown in FIG. 1 includes an n-type single crystal silicon substrate 11, i-type amorphous silicon layers 12 and 13, which are substantially intrinsic amorphous silicon layers, and a doped amorphous silicon layer (doped layer). ), The p-type amorphous silicon layer 14 and the n-type amorphous silicon layer 15, the transparent conductive layers 16 and 17, and the current collecting electrodes 18 and 19 formed of the conductive paste composition are provided. The solar cell 10 is a hetero with reduced defects at the pn junction interface by sandwiching the n-type single crystal silicon substrate 11 between substantially intrinsic amorphous silicon layers (i-type amorphous silicon layers 12 and 13). It is a junction type.

The n-type single crystal silicon substrate 11 has a thickness of about 300 μm, and its upper surface (surface, light receiving surface) has a texture structure (pyramid-like unevenness having a height of about several μm to 10 μm) not shown in FIG. Structure) is provided. An i-type amorphous silicon layer 12 having a thickness of 50 Å is formed on the upper surface of the n-type single crystal silicon substrate 11 by the RF plasma CVD method, and a p-type amorphous silicon layer 14 having a thickness of 50 Å is formed on the i-type amorphous silicon layer 14 by the RF plasma CVD method. Formed in.

Further, an i-type amorphous silicon layer 13 having a thickness of 50 Å is formed on the lower surface (back surface, opposite surface) of the n-type single crystal silicon substrate 11 by the RF plasma CVD method, and an n-type amorphous silicon layer having a thickness of 50 Å is formed on the i-type amorphous silicon layer 13 by the RF plasma CVD method. The silicon layer 15 was formed by the RF plasma CVD method. Further, transparent conductive layers 16 and 17 (both indium tin oxide (ITO)) having a thickness of 1000 Å were formed on the p-type amorphous silicon layer 14 and the n-type amorphous silicon layer 15 by magnetron sputtering method.

A predetermined print pattern is formed on each of the transparent conductive layers 16 and 17 by a screen printing method using the conductive paste composition of the example or the comparative example, and the print pattern is heat-cured at 200 ° C. for 30 minutes. By doing so, the current collecting electrodes 18 and 19 were formed. The current collecting electrode 18 on the light receiving surface side has a finger opening of 30 μm and the number of fingers is 100, and the current collecting electrode 19 on the opposite surface side has a finger opening of 30 μm and the number of fingers is 200. be.

[Line width of current collector electrode]
For the solar cell 10 manufactured (manufactured) as described above, the line widths of the current collector electrodes 18 and 19 were measured using a microscope (manufactured by KEYENCE CORPORATION).

[Line resistance of current collector electrode]
With respect to the solar cell 10 manufactured (manufactured) as described above, the linear resistances of the current collector electrodes 18 and 19 were evaluated using a GP4 test (product name, manufactured by GP solar).

[Cell characteristics]
The solar cell 10 manufactured (manufactured) as described above is inspected for IV characteristics using a solar cell inspection system (manufactured by Kyoshin Electric Co., Ltd., trade name: KSX-3000H). The cell characteristics were evaluated. When the cell characteristic was less than 23.3%, it was considered unsuitable.

[Creating a solar cell module]
Using the solar cell 10 manufactured (manufactured) as described above, the solar cell module 20 illustrated in FIG. 2 was manufactured (manufactured).

In the solar cell module 20 shown in FIG. 2, a plurality of solar cell 10s (four shown in FIG. 2) are connected by a tab 21 which is a wiring, and these are connected to the filler 22, the front surface protective glass 23, and the back surface protective material 24. It has a structure sealed with.

The tab 21 is composed of a copper foil whose surface is coated with Sn-Ag-Cu-based lead-free solder. The tab 21 was brought into contact with the current collecting electrodes 18 and 19 of the plurality of solar cells 10 to heat them, and these solar cells 10 were connected in series. Thereby, the current obtained by the power generation by each solar cell 10 can be taken out.

Next, a filler 22 made of ethylene-vinyl acetate copolymer (EVA) is placed on the surface protective glass 23, and then a plurality of solar cells 10 connected by tabs 21 are placed on the filler 22. Placed. Further, a filler 22 made of EVA is placed on these solar cells 10, and a back surface protective material 24 having a three-layer structure of polyethylene terephthalate (PET) / aluminum foil / PET is placed and added while heating. Pressed. As a result, the front surface protective glass 23, the filler 22, the plurality of solar cell 10 connected by the tab 21, and the back surface protective material 24 were integrated to obtain the solar cell module 20 shown in FIG.

[Moisture resistance of solar cell module]
The solar cell module 20 manufactured (manufactured) as described above is stored in a constant temperature and humidity controller (manufactured by ESPEC CORPORATION, trade name: SMS-2) set to a temperature of 85 ° C. and a humidity of 85% for 3000 hours. did. The module output of the solar cell module 20 before and after storage was evaluated using a solar cell module inspection system (trade name: KSX-2012HM) manufactured by Kyoshin Electric Co., Ltd. When the amount of decrease in conversion efficiency after storage was less than 5%, it was evaluated as "◯", and when the amount of decrease in conversion efficiency after storage was 5% or more, it was evaluated as "x".

[Components (A) to (C)]
In the conductive paste composition of Examples or Comparative Examples described later, as the resin component (A), 7 types of epoxy resins shown in Table 1, 3 types of urethane resins, and 1 type of other resin (butyral resin) are used. board. In each Example or Comparative Example, each resin is described by using the abbreviations shown in Table 1.

Further, in the conductive paste composition of Examples or Comparative Examples described later, three kinds of silver-containing powders (silver-based powders) shown in Table 2 were used as the conductive powder (B). In each Example or Comparative Example, each silver-containing powder is described by using the abbreviations shown in Table 2 as in the case of the resin component (A).

Further, in the conductive paste composition of Examples or Comparative Examples described later, seven types of silicone oils shown in Table 3 were used as the (C) silicone oil component. In each Example or Comparative Example, each silicone oil is described by using the abbreviations shown in Table 3, as in the case of (A) resin component or (B) conductive powder.

(Examples 1 to 3)
The epoxy resin of the abbreviation E-3 and the urethane resin of the abbreviation U-2 are selected from the (A) resin components shown in Table 1, and the silver powder 1 of the abbreviation Pa-1 is selected from the (B) conductive powders shown in Table 2. (Spherical) and silver powder 2 (flakes) of the abbreviation Pa-2 were selected, and the straight silicone oil of the abbreviation S-3 was selected from the (C) silicone oil components shown in Table 3.

As for the (B) conductive powder, silver powder 1 (Pa-1) and silver powder 2 (Pa-2) are 50 parts by mass each as shown in Table 4, for a total of 100 parts by mass, and the conductive powder (B) is the same. The resin component (A) and the silicone oil component (C) were blended in the composition (blending amount) shown in Table 4 with respect to 100 parts by mass of the total amount.

In Table 4, regarding the composition of the (A) resin component, the content Z of the (A) resin component, that is, the total Z of the content (blending amount) of the resin constituting the (A) resin component is referred to as “parts by mass”. , And the content (blending amount) of each resin is not shown by "parts by mass", but by (A) the ratio (percentage) when the whole resin component is 100% by mass. Therefore, in the conductive paste composition of Example 1, the content Z (total blending amount) of the resin component (A) is 4 parts by mass, but the epoxy resin of the abbreviation E-3 is "0 (%)". Since the urethane resin of the abbreviation U-2 is "100 (%)", it means that only the urethane resin of the abbreviation U-2 is contained in 4 parts by mass as the resin component (A).

Similarly, in the conductive paste composition of Example 3, the epoxy resin of the abbreviation E-3 is "100 (%)" and the urethane resin of the abbreviation U-2 is "0 (%)". A) As a resin component, only the epoxy resin of the abbreviation E-3 is contained in 6 parts by mass.

Further, in the conductive paste composition of Example 2, the epoxy resin of the abbreviation E-3 is "30 (%)" and the urethane resin of the abbreviation U-2 is "70 (%)" (A). ) Since the content Z of the resin component is "5 parts by mass", (A) as the resin component, the epoxy resin of the abbreviation E-3 is "1.5 parts by mass" and the urethane resin of the abbreviation U-2 is ". It will contain "3.5 parts by mass".

Further, in Table 4, for each example, not only the content Z (total blending amount) of the resin component (A) but also the above-mentioned molecular weight average value WMn, that is, one or more kinds constituting the resin component (A) or more. The product (WMn × Z ² ) of the weighted average value WMn of the number average molecular weight in the resin and the square of the molecular weight average value WMn and the content Z of the resin component (A), that is, the condition of the above formula (1) is also described. is doing. In addition, Table 4 also shows (C) the molecular weight of the silicone oil used as the silicone oil component (see Table 3).

Regarding the description of (A) the resin component and the description of the molecular weight of (C) the silicone oil component, not only Examples 1 to 3 shown in Table 4 and Examples 4 to 6 described later, but also other examples. Since the same applies to Tables 5 to 9 showing comparative examples, detailed description thereof will be omitted in each Example or Comparative Example.

An imidazole-based curing agent (product name: Curesol (registered trademark) 1B2PZ, manufactured by Shikoku Chemicals Corporation) is further used as a curing agent for each of the components (A) to (C) blended in the blending amounts shown in Table 4. The mixture was mixed in a proportion of 0.1 parts by mass and kneaded with a 3-roll mill. Then, butyl diglycol acetate was added as a solvent to adjust the viscosity to 300 Pa · s (1 rpm) to prepare (manufacture) the conductive paste compositions of Examples 1 to 3.

Using the obtained conductive paste compositions of Examples 1 to 3, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 4.

(Examples 4 to 6)
(A) The same procedure as in Examples 1 to 3 was carried out except that the epoxy resin of the abbreviation E-2 and the urethane resin of the abbreviation U-3 shown in Table 1 were used as the resin components in the blending amounts shown in Table 4. The conductive paste compositions of Examples 4 to 6 were prepared (manufactured).

Using the obtained conductive paste compositions of Examples 4 to 6, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 4.

(Examples 7 to 10)
As the (A) resin component, the epoxy resin of the abbreviation E-1 shown in Table 1 and the epoxy resin of any of the abbreviations E-4 to E-7 are used, and as the (C) silicone oil component, S-shown in Table 3 is used. Conductive pastes of Examples 7 to 10 in the same manner as in Examples 1 to 3 (see Table 4) except that the silicone oils 1 to S-4 were used in the blending amounts shown in Table 5, respectively. The composition was prepared (manufactured).

Using the obtained conductive paste compositions of Examples 7 to 10, a solar cell 10 (see FIG. 1) and a solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and a current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 5.

(Examples 11 and 12)
As the resin component (A), the epoxy resin of the abbreviation E-6 and the urethane resin of the abbreviation U-1 shown in Table 1 are used in the blending amounts shown in Table 6, and as the (C) silicone oil component, they are shown in Table 3. The conductive paste compositions of Examples 11 and 12 were prepared in the same manner as in Examples 1 to 3 (see Table 4) except that the silicone oil of S-1 or S-2 was used in the blending amounts shown in Table 6. Prepared (manufactured).

Using the obtained conductive paste compositions of Examples 11 and 12, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 6.

(Example 13)
As shown in Table 6, (B) the same as in Example 12 except that the silver-coated copper powder of the abbreviation Pa-3 shown in Table 2 was used instead of the silver powder 2 of the abbreviation Pa-2 as the conductive powder. The conductive paste composition of Example 13 was prepared (manufactured).

Using the obtained conductive paste composition of Example 13, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 5.

(Example 14)
As shown in Table 6, (A) the content Z (total amount) of the resin component is 7 parts by mass, and (C) the modified silicone oil of the abbreviation S-5 shown in Table 3 is used as the silicone oil component. The conductive paste composition of Example 14 was prepared (manufactured) in the same manner as in Example 12 except that it was used.

Using the obtained conductive paste composition of Example 14, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 6.

(Example 15)
(A) As the resin component, in addition to the epoxy resin of the abbreviation E-6 and the urethane resin of the abbreviation U-1 shown in Table 1, other resins (butyral resin) of the abbreviation B-1 are used in the blending amounts shown in Table 6. The conductive paste composition of Example 15 was prepared (manufactured) in the same manner as in Example 11.

Using the obtained conductive paste composition of Example 15, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 6.

(Examples 16 and 17)
(A) Same as Example 9 (see Table 5) except that the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 were used as the resin components in the blending amounts shown in Table 7. The conductive paste compositions of Examples 16 and 17 were prepared (manufactured).

Using the obtained conductive paste compositions of Examples 16 and 17, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 7.

(Comparative Examples 1 and 2)
As the resin component (A), the epoxy resin of the abbreviation E-1 and the urethane resin of the abbreviation U-3 (Comparative Example 1) or the urethane resin of the abbreviation U-1 (Comparative Example 2) shown in Table 1 are shown in Table 7. The conductive paste compositions of Comparative Examples 1 and 2 were prepared (manufactured) in the same manner as in Examples 1 to 3 (see Table 4) except that they were used in the blending amount. In Comparative Examples 1 and 2, the condition (WMn × Z ² ) of the above formula (1) is below the lower limit of the above-mentioned range.

Using the obtained conductive paste compositions of Comparative Examples 1 and 2, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 7.

(Comparative Examples 3 and 4)
As the (A) resin component, the epoxy resin of the abbreviation E-3 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 7, and as the (C) silicone oil component, the abbreviations shown in Table 3 are used. The conductive paste compositions of Comparative Examples 3 and 4 were prepared (produced) in the same manner as in Examples 7 to 10 (see Table 5) except that the straight silicone oil of S-3 was used in the blending amounts shown in Table 7. )did. In Comparative Examples 3 and 4, the condition (WMn × Z ² ) of the above formula (1) exceeds the upper limit value in the above-mentioned range.

Using the obtained conductive paste compositions of Comparative Examples 3 and 4, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode was used. The line widths and resistances of 18 and 19, the cell characteristics of the solar cell 10, and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 7.

(Comparative Example 5)
As the (A) resin component, the epoxy resin of the abbreviation E-3 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 8, and as the (C) silicone oil component, the abbreviations shown in Table 3 are used. The conductive paste composition of Comparative Example 5 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5) except that the straight silicone oil of S-3 was used in the blending amount shown in Table 8. .. In Comparative Example 5, the content of the (C) silicone oil component exceeds the upper limit.

Using the obtained conductive paste composition of Comparative Example 5, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparative Example 6)
As the resin component (A), the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 were used in the blending amounts shown in Table 8, except that the (C) silicone oil component was not used. The conductive paste composition of Comparative Example 6 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5).

Using the obtained conductive paste composition of Comparative Example 6, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparative Example 7)
As the (A) resin component, the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 8, and as the (C) silicone oil component, the abbreviations shown in Table 3 are used. The conductive paste composition of Comparative Example 7 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5) except that the straight silicone oil of S-3 was used in the blending amount shown in Table 8. .. In Comparative Example 7, the content of the (C) silicone oil component is below the lower limit.

Using the obtained conductive paste composition of Comparative Example 7, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparative Example 8)
As the (A) resin component, the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 8, and as the (C) silicone oil component, the abbreviations shown in Table 3 are used. The conductive paste composition of Comparative Example 8 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5) except that the straight silicone oil of S-6 was used in the blending amount shown in Table 8. .. In Comparative Example 8, the molecular weight of the (C) silicone oil component is below the lower limit.

Using the obtained conductive paste composition of Comparative Example 8, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparative Example 9)
As the (A) resin component, the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 8, and as the (C) silicone oil component, the abbreviations shown in Table 3 are used. The conductive paste composition of Comparative Example 9 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5) except that the straight silicone oil of S-7 was used in the blending amount shown in Table 8. .. In Comparative Example 9, the molecular weight of the (C) silicone oil component is below the upper limit.

Using the obtained conductive paste composition of Comparative Example 9, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparative Example 10)
(A) As the resin component, the epoxy resin of the abbreviation E-2 and the epoxy resin of the abbreviation E-7 shown in Table 1 are used in the blending amounts shown in Table 8, and the straight silicone oil of the abbreviation S-3 shown in Table 3 is used. The conductive paste composition of Comparative Example 5 was prepared (manufactured) in the same manner as in Examples 7 to 10 (see Table 5) except that it was used in the blending amounts shown in Table 8. In Comparative Example 10, the content of the (C) silicone oil component exceeds the upper limit.

Using the obtained conductive paste composition of Comparative Example 10, the solar cell 10 (see FIG. 1) and the solar cell module 20 (see FIG. 2) were manufactured (manufactured) as described above, and the current collecting electrode 18 and the current collecting electrode 18 and the solar cell module 20 were manufactured. The line width and line resistance of 19 and the cell characteristics of the solar cell 10 and the moisture resistance of the solar cell module 20 were evaluated. The results are shown in Table 8.

(Comparison between Examples and Comparative Examples)
As is clear from the results of Examples 1 to 17, in the conductive paste composition according to the present disclosure, a current collecting electrode having a fine line width is formed even when the transparent conductive layer (transparent electrode film) is used as a base layer. At the same time, it is possible to effectively suppress or avoid an increase in the line resistance of the current collecting electrode. Moreover, the solar cell provided with the current collecting electrode (the solar cell according to the present disclosure) can realize good cell characteristics, and further, the solar cell module provided with the solar cell (the solar cell according to the present disclosure). ) Can realize good moisture resistance, so that good long-term reliability as a solar cell module can be realized.

For example, as is clear from the results of Examples 1 to 6 (Table 4) or the results of Examples 11 to 14 (Table 6), even if the epoxy resin and the urethane resin are used in combination as the resin component (A), they are not used in combination. However, good results can be obtained if the composition of the conductive paste composition according to the present disclosure is used. Further, as is clear from the results of Examples 7 to 10, 16 and 17 (Table 5), even if only two types of epoxy resin (A) are used as the resin component, the constitution of the conductive paste composition according to the present disclosure is satisfied. If so, good results can be obtained. (A) Similarly, good results can be obtained even if three or more types of epoxy resins are used as the resin component or two or more types of urethane resins are used.

As is clear from the results of Example 13, even when (B) silver-coated copper powder is used as the conductive powder, good results can be obtained if the composition of the conductive paste composition according to the present disclosure is used. can. Even if (B) the conductive powder is a metal powder other than silver powder or a powder other than a metal having conductivity, or (B) even if there is only one type of conductive powder, the combination of the two types is not one-to-one. Even if three or more kinds are mixed, good results can be obtained in the same manner.

As is clear from the results of Example 14, even if the (C) silicone oil component is a modified silicone oil instead of a straight silicone oil, good results can be obtained if the composition of the conductive paste composition according to the present disclosure is used. Obtainable.

As is clear from the results of Example 15, even if (A) a resin component is used in addition to the epoxy resin and urethane resin, the basic resin component is 70% by mass or more of the total amount of the (A) resin component. If so, good results can be obtained. Similarly, good results can be obtained even if the basic resin component is only an epoxy resin (one type or two or more types) or only a urethane resin (one type or two or more types).

As is clear from any comparison of the results of Examples 1 to 17, even if the type, molecular weight, combination, and total blending amount (content Z) of the resin constituting the resin component are changed (A), the above If the condition of the formula (1) (WMn × Z ² ) is within a predetermined range (that is, if the composition of the conductive paste composition according to the present disclosure is used), good results can be obtained. Similarly, as is clear from the results of Examples 1 to 17 (particularly Examples 7 to 15), even if various types of silicone oils are used as the (C) silicone oil component (modified silicone oil of Example 14). (Including), if the molecular weight of the silicone oil is within the predetermined range and the blending amount is within the predetermined range (if the composition of the conductive paste composition according to the present disclosure), good results can be obtained. can.

On the other hand, as is clear from the results of Comparative Examples 1 to 4, if the condition (WMn × Z ² ) of the above formula (1) is out of the predetermined range, not only good cell characteristics cannot be obtained but also good cell characteristics cannot be obtained. , The line width becomes thicker (Comparative Examples 1 and 2), the line resistance becomes higher (Comparative Examples 3 and 4), and good moisture resistance (that is, long-term stability) cannot be achieved (Comparative Examples 1 and 2). ).

Further, as is clear from the results of Comparative Examples 5 to 7, 10, even if the molecular weight of the silicone oil is within a predetermined range, good results cannot be obtained if the blending amount is outside the predetermined range. You can see that. In particular, when (C) the silicone oil component is not contained (blended) (Comparative Example 6) or the content (blended amount) is small (Comparative Example 7), only good cell characteristics cannot be obtained. Instead, you can see that the line width becomes thicker. Further, when the amount of (C) silicone oil component increases (Comparative Examples 5 and 10), good moisture resistance may not be obtained, and the long-term reliability of the solar cell module may decrease.

Further, as is clear from the results of Comparative Examples 8 and 9, even if the blending amount of the silicone oil is within the predetermined range, the molecular weight of the silicone oil may be smaller than the predetermined range or larger than the predetermined range (Comparative Example 8). In (Comparative Example 9), it can be seen that not only good cell characteristics cannot be obtained, but also the line width becomes thicker (Comparative Example 8) and the line resistance becomes higher (Comparative Example 9).

As described above, in the conductive paste composition according to the present disclosure, (A) the resin component is at least one of the epoxy resin and the urethane resin, and (B) the content of the conductive powder is used as a reference. The content Z of the resin component (A) and the molecular weight average value WMn of the resin component (A) are set so as to satisfy the condition (WMn × Z ² = 5 × 10 ³ to 3 × 10 ⁵ ) of the formula (1). At the same time, (C) the number average molecular weight and the content of the silicone oil component are set. As a result, as in the above-described embodiment or comparative example, in an electronic device or electronic component such as a solar cell or a solar cell module, an electrode or wiring such as a current collector electrode is avoided while avoiding a large influence on the performance thereof. It is possible to realize good fine line drawability when forming the above.

It should be noted that the present invention is not limited to the description of the above-described embodiment, and various modifications can be made within the scope of the claims, and the present invention is disclosed in different embodiments and a plurality of modifications. Embodiments obtained by appropriately combining the above technical means are also included in the technical scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be suitably used in the field of manufacturing various electronic devices and electronic components, and in particular, a current collecting electrode of a solar cell, an internal electrode or an external electrode of a chip-type electronic component, an RFID, an electromagnetic wave shield, and a vibrator adhesion. , Membrane switches, touch electrodes, electrodes or wiring of parts used for electroluminescence, etc., can be widely and suitably used in fields where higher definition electrodes or wiring are formed, or adhesion of electronic parts is required.

10: Solar cell 11: n-type single crystal silicon substrate 12: i-type amorphous silicon layer 13: i-type amorphous silicon layer 14: p-type amorphous silicon layer 15: n-type amorphous silicon layer 16: transparent conductive layer (transparent electrode film) )
17: Transparent conductive layer (transparent electrode film)
18: Current collector electrode (printing pattern of conductive paste composition)
19: Current collector electrode (printing pattern of conductive paste composition)
20: Solar cell module 21: Tab 22: Filler 23: Front surface protective glass 24: Back surface protective material

Claims (6)

It contains (A) a resin component, (B) a conductive powder, and (C) a silicone oil component.
The resin component (A) contains at least one of an epoxy resin and a urethane resin, and
When the content of the (A) resin component with respect to 100 parts by mass of the (B) conductive powder is Z parts by mass, and the weighted average value of the number average molecular weight of the resin constituting the (A) resin component is WMn. , Satisfy the condition of the following formula (1),
WMn x Z ² = 5 x 10 ³ to 3 x 10 ⁵ ... (1)
The (C) silicone oil component is at least one of straight silicone oil and modified silicone oil, and the number average molecular weight thereof is in the range of 1 × ^{10 3} to 1 × 105.
The content of the (C) silicone oil component with respect to 100 parts by mass of the (B) conductive powder is in the range of 0.1 to 2.4 parts by mass.
Thermosetting conductive paste composition. When at least one of the epoxy resin and the urethane resin in the resin component (A) is used as the basic resin component, the resin component (A) further contains a resin other than the basic resin component and also contains other resins.
The total content of the basic resin component in the (A) resin component is 70% by mass or more of the total amount of the (A) resin component.
The thermosetting conductive paste composition according to claim 1. The conductive powder (B) is silver powder or silver-containing powder.
The thermosetting conductive paste composition according to claim 1 or 2. A solar cell comprising a current collecting electrode formed by the thermosetting conductive paste composition according to any one of claims 1 to 3. Further provided with a transparent conductive layer which is a base layer of the current collector electrode.
The solar cell according to claim 4. A solar cell module comprising the solar cell according to claim 4 or 5.

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