KR20120004122A - Electrode paste and electrode using the same - Google Patents

Abstract

PURPOSE: An electrode paste is provided to achieve excellent electrical property with minimizing manufacturing cost, and to use for high-temperature plasticizing type and low-temperature plasticizing type, and to have excellent conductivity and adhesion. CONSTITUTION: An electrode paste comprises conductive powder and an organic vehicle. The conductive powder is mixture of 30-90wt% plate-like powder, 1-30wt% spherical powder, and 1-60wt% agglomerative powder. The conductive powder is one metal or the alloy of two or more metals selected from the group consisting of silver, gold, palladium, platinum, copper, chrome, cobalt, aluminum, tin, lead, zinc, iron, iridium, osmium, rhodium, tungsten, molybdenum and nickel.

Description

Electroconductive paste and electrode using the same {Electrode Paste and Electrode Using the same}

The present invention relates to a conductive paste and an electrode using the same. More specifically, the present invention relates to a conductive paste having an excellent electrical property and adhesiveness and an electrode using the same by using a combination of three powders of plate-like, spherical and agglomerated type as the conductive powder used in the conductive paste.

The conductive paste is used in various ways, such as solar cell electrodes, electrodes of display substrates, integrated circuit boards, conductive wires, die bonding, and the like. Such conductive pastes form conductive coatings by printing, coating, drying, heat treatment, curing, and the like.

As the printing method, a screen printing method is usually used, and the conductive paste for screen printing includes high temperature baking type and low temperature curing type. In the case of the high temperature plastic type, it is possible to impart excellent conductivity, but there is a problem in that the manufacturing cost is increased and the adhesive strength is lowered or the precision is lowered. On the other hand, in the case of low-temperature curing type is excellent in terms of precision, etc., but has a relatively poor conductivity.

In Korean Patent Publication No. 2010-0029652, flat plate flakes having a particle size distribution of 1 to 10 microns and a particle size of 100 to 500 nanometers are used in order to improve the conduction characteristics at low temperature, or a mixture of powders or 0030441 discloses the use of 10-20 nano-sized ultrafine particles and 1-10 micron-sized silver powder.

However, in the related art, high cost nanoparticles or thin film flakes are used to increase product costs and have not obtained satisfactory levels in terms of conductivity.

Accordingly, there is a need for the development of a conductive paste and an electrode using the same, which can not only provide excellent conductivity and adhesion even in both a high temperature baking type and a low temperature curing type.

It is an object of the present invention to provide a conductive paste capable of achieving high electrical properties while minimizing manufacturing costs.

Another object of the present invention is to provide a conductive paste that can be applied to both a high temperature baking type and a low temperature curing type.

Still another object of the present invention is to provide a conductive paste capable of imparting excellent conductivity and adhesion.

Still another object of the present invention is to provide a conductive paste that can be used as an electrode of a HIT solar cell or a thin film solar cell, which requires particularly low temperature characteristics.

It is a further object of the present invention to provide a conductive paste that can also be used for screen printing for electrical and electronic device components.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the invention relates to conductive pastes. The conductive paste includes a conductive powder and an organic vehicle, and the conductive powder is characterized by mixing (iii) plate-shaped powder, (ii) spherical powder and (iii) agglomerated powder.

In an embodiment, the conductive powder is silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), tin (Sn) ), Lead (Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo) and nickel (Nickel) It may be any one or more selected or two or more alloys thereof.

The conductive powder may be composed of (i) 30 to 90% by weight of plate-like powder, (ii) 1 to 30% by weight of spherical powder and (i) 1 to 60% by weight of agglomerated powder.

In an embodiment, the (iii) plate-shaped powder has an average particle diameter (D50) of 0.5 to 5 ㎛, the (ii) spherical powder has an average particle diameter (D50) of 0.1 to 3 ㎛, the (iii) agglomerated powder The average particle diameter (D50) may be 1 to 10 ㎛.

In another embodiment, the (iii) plate-shaped powder has an average particle diameter (D90) of 2 to 8 µm, the (ii) spherical powder has an average particle diameter (D90) of 0.5 to 5 µm, and the (iii) aggregated powder The average particle diameter (D90) may be 5 to 15 ㎛.

In an embodiment, the (i) agglomerated powder may have a specific surface area of 0.5 to 5 m ² / g and a tap density of 0.5 to 4.5 g / cm ³ .

In one embodiment, the conductive paste may further include a glass frit.

The conductive paste may include 2 to 30 parts by weight of an organic vehicle with respect to 100 parts by weight of conductive powder.

In embodiments, the organic vehicle may include an organic binder, a diluent, and a solvent. In an embodiment, the organic vehicle may include 0.5 to 15 parts by weight of the organic binder, 0.5 to 5 parts by weight of the diluent and 1 to 10 parts by weight of the solvent based on 100 parts by weight of the conductive powder.

In embodiments, the conductive paste may further include one or more selected from the group consisting of aluminum oxide, antimony oxide, zinc oxide, lead oxide and copper oxide.

The conductive paste may further include one or more additives such as a hardener, a dispersant, a thixotropic agent, a viscosity stabilizer, an antifoaming agent, a pigment, an ultraviolet stabilizer, an antioxidant, an inorganic filler, and a coupling agent.

Another aspect of the invention relates to an electrode formed from the conductive paste.

Another aspect of the invention relates to a method of manufacturing the electrode. In an embodiment the method prints the conductive paste; And it is characterized in that the printed paste is cured at 150 to 250 ℃.

The present invention can achieve high electrical properties while minimizing the manufacturing cost, can be applied to both high-temperature firing and low-temperature curing type, can give excellent conductivity and adhesion, especially HIT solar cell or thin film type solar cells that require low temperature characteristics The present invention has the effect of providing a conductive paste suitable for the electrode of a battery and usable for screen printing for electric and electronic component parts.

1 is a SEM photograph of the aggregated powder used in the Examples and Comparative Examples. (a) is magnified 10,000 times, and (b) is a 5000 times magnified photograph.

The conductive paste of the present invention comprises a conductive powder and an organic vehicle.

Conductive powder

As the conductive powder used in the present invention, both conductive organic and inorganic materials may be used.

Specific examples include silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), tin (Sn), and lead ( Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo), nickel and the like can be used. Such conductive powder may be used alone or in combination of two or more thereof, and may be in the form of two or more alloys. Preferably, the conductive powder includes silver (Ag) particles, and nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn) or copper (Cu) particles may be further added in addition to the silver particles. .

In the present invention, the conductive powder includes all of the forms of (i) plate-shaped powder, (ii) spherical powder and (iii) agglomerated powder.

The (iii) plate-like powder has a flake or flat shape in the form of flat and thin pieces, and is easy to purchase commercially. In an embodiment, the (iii) plate-shaped powder may have a maximum length: width ratio of 1: 1 to 5: 1. The thickness may also be 1/100 to 1/5 of the maximum length.

In one embodiment, the (iii) plate-shaped powder may have an average particle diameter (D50) of 0.5 to 5 ㎛, preferably 1 to 3.5 ㎛. In addition, the (iii) plate-shaped powder may have an average particle diameter (D90) of 2 to 8 ㎛, preferably 3 to 7.5 ㎛, more preferably 5 to 7 ㎛. In an embodiment, the average particle diameter (D10) of the (iii) plate-shaped powder may be 0.05 to 2 μm, preferably 0.1 to 1 μm. The "average particle diameter" referred to in the present invention is measured by SEM based on the maximum length. (Iii) The particle size of the plate-shaped powder has an advantage of excellent contact resistance and wire resistance with a transparent conductive oxide (TCO) within the above range.

In addition, the (iii) plate-shaped powder has a specific surface area of 0.1 to 1 m ² / g, preferably 0.2 to 0.6 m ² / g, tap density of 3 to 7 g / cm ³ , preferably 4 to May be 5.5 g / cm ³ . In the above range, the maximum filling amount of the electrode is increased, so the resistance is excellent.

The (ii) spherical powder is a particle having a substantially spherical or elliptical shape, and can be easily purchased commercially. In embodiments, the (ii) spherical powder may have a short diameter: long diameter ratio of 1: 1 to 1: 2.

In one embodiment, the (ii) spherical powder may have an average particle diameter (D50) of 0.1 to 3 μm, preferably 0.5 to 2 μm. In addition, the (ii) spherical powder may have an average particle diameter (D90) of 0.5 to 5 μm, preferably 1 to 3.5 μm, and more preferably 2 to 3 μm. In an embodiment, the average particle diameter (D10) of the (ii) spherical powder may be 0.1 to 2 μm, preferably 0.3 to 1 μm. (Ii) The particle size of the spherical powder is good in interaction with the plate-shaped powder within the above range and has an advantage of excellent resistance.

As shown in FIG. 1, the (iii) agglomerated powder has a porous particle structure in the form of agglomerated small particles. In an embodiment, the (i) agglomerated powder may be prepared by re-wetting and granulating small powder particles by moist air or steam and the like, and are easily purchased commercially.

In one embodiment, the (i) agglomerated powder may have an average particle diameter (D50) of 1 to 10 µm, preferably 3 to 8 µm, and more preferably 4 to 6 µm. In addition, the (g) agglomerated powder may have an average particle diameter (D90) of 5 to 15 µm, preferably 6.5 to 13 µm, and more preferably 7 to 12 µm. In an embodiment, the average particle diameter (D10) of the (i) agglomerated powder may be 1 to 5 μm, preferably 2 to 3.5 μm. (Iii) The particle size of the agglomerated powder has an advantage of good resistance due to good interaction with the plate-shaped powder within the above range.

In addition, the (i) agglomerated powder may have a specific surface area of 0.5 to 5 m ² / g, preferably 0.7 to 3 m ² / g, and a tap density of 0.5 to 4.5 g / cm ³ , preferably 1 To 3 g / cm ³ . In the above range, the maximum filling amount of the electrode is increased, so the resistance is excellent.

In an embodiment, the conductive powder may be composed of (i) 30 to 90 wt% of the plate-shaped powder, (ii) 1 to 30 wt% of the spherical powder and (i) 1 to 60 wt% of the (a) coagulated powder. Preferably, the conductive powder may be composed of (i) 35 to 85% by weight of the plate-shaped powder, (ii) 5 to 20% by weight of the spherical powder and (i) 5 to 55% by weight of the aggregated powder. There is an advantage of excellent resistance within the above range.

In one embodiment, the (iii) plate-like powder, (ii) spherical powder and (iii) aggregated powder may be applied to the same or different metals. For example, the (iii) plate-shaped powder, (ii) spherical powder and (iii) agglomerated powder are all made of silver powder, or the (iii) plate-shaped powder and (ii) spherical powder are copper powder. The powder can be used as a silver powder. In another embodiment, one conductive powder and the other conductive powder may be mixed and used to have the form of (i) plate-like, (ii) spherical and (i) aggregated. In another embodiment, the (iii) plate-shaped, (ii) spherical powder or (iii) agglomerated powder may be present in the form of a coating, an alloy, a mixture of the first conductive powder and the second conductive powder. For example, in the spherical powder, the first conductive metal may be coated inside and the second conductive metal may be coated together. In addition, the aggregated powder may have a form in which two or more conductive powders are aggregated together.

The conductive powder is 50 to 95% by weight, preferably 75 to 92% by weight of the whole paste. When the content is less than 50% by weight, the Rs (Series Resistance) and FF (Fill Factor) may be poor due to an increase in resistance, and may cause a problem such as short circuit of the electrode. This may be relatively small, which makes it difficult to paste.

Organic vehicle ( vehicle )

The organic vehicle may be an organic binder that provides liquid properties to the paste, and may further include a solvent.

In embodiments, the organic vehicle may include an organic binder, a diluent, and a solvent.

The organic vehicle may include 2 to 30 parts by weight based on 100 parts by weight of the conductive powder. Excellent adhesion and precise line width can be obtained within the above range.

The organic binder may be an epoxy resin, an acrylic resin, a methacryl resin, a cellulose resin, an ester resin, an alkyd resin, a butyral resin, a PVA resin, or the like, but is not limited thereto. Of these, epoxy resins preferably exhibit the best adhesion. The organic binder may be used in an amount of 0.5 to 15 parts by weight, preferably 1 to 10 parts by weight, and more preferably 4 to 8 parts by weight, based on 100 parts by weight of the conductive powder. If the content is more than 15 parts by weight, the organic binder may act as a resistor, and thus the line resistance may deteriorate. If the content is less than 0.5 part by weight, the paste may be difficult to form.

As the diluent, an epoxy compound such as epoxy acrylate may be used, but is not necessarily limited thereto. The diluent may be used in an amount of 0.5 to 5 parts by weight, preferably 2 to 4 parts by weight, based on 100 parts by weight of the conductive powder. Within the above range, there is an effect of increasing flexibility and decreasing resistance of the electrode.

As the solvent, an organic solvent having a boiling point of 120 ° C. or higher may be used. Specific examples include Methyl Cellosolve, Ethyl Cellosolve, Butyl Cellosolve, Aliphatic Alcohol, Terpineol, Ethylene Grycol, Ethylene Glycol Monobutyl Ethylene glycol mono butyl ether, butyl cellosolve acetate, Texanol butyl carbitol acetate, and the like may be used, but are not necessarily limited thereto. These can be used individually or in mixture of 2 or more types. The solvent may be included in 1 to 10 parts by weight, preferably 2 to 5 parts by weight based on 100 parts by weight of the conductive powder.

In one embodiment, the conductive paste may further include a glass frit. The glass frit may be a crystallized glass frit, an amorphous glass frit, or a combination thereof. The glass frit may have an average particle diameter (D50) of 0.1 to 5㎛.

In another embodiment, the conductive paste may further include metal oxides such as aluminum oxide, antimony oxide, zinc oxide, lead oxide, copper oxide, and the like. The metal oxides may be used alone or in combination of two or more thereof. The metal oxide may have an average particle diameter (D50) of 0.1 to 25㎛, more preferably 1.5 to 10㎛. The metal oxide may be added in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the conductive powder.

The conductive paste of the present invention may further include at least one additive such as a curing agent, a dispersant, a thixotropic agent, a viscosity stabilizer, an antifoaming agent, a pigment, an ultraviolet stabilizer, an antioxidant, an inorganic filler, and a coupling agent. These are all known enough to be commercially available to those of ordinary skill in the art, so specific examples and descriptions thereof will be omitted.

The conductive paste of the present invention can be used for electrode formation of various electric and electronic materials, or for packaging or assembly, screen printing for electric and electronic device parts, and the like. In particular, it can be preferably applied to the electrode of the HIT solar cell or thin-film solar cell that requires low temperature characteristics.

Another aspect of the invention relates to an electrode formed from the conductive paste. The electrode prints the conductive paste; And it can be prepared by curing the printed paste at 150 to 250 ℃.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, this is presented as a preferred example of the present invention and in no sense can be construed as limiting the present invention.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Example

The specifications of each component used in the following Examples and Comparative Examples are as follows:

(A) Conductive powder: As the silver (Ag) powder, those shown in Table 1 below were used, respectively. The SEM photograph of the aggregated powder is shown in FIG. 1. (a) is 10,000 times magnification and (b) is 5,000 times magnification.

shape Tap density
(g / cm ³⁾ Average particle diameter
(D10) µm Average particle diameter
(D50) µm Average particle diameter
(D90) µm Specific surface area
(m ² / g) manufacturer Grade (Ⅰ) plate type 4.9 0.4 2 6.0 0.4 Technic 499 (Ii) spherical 5.4 0.7 1.5 2.4 0.7 Technic 574 (Ⅲ) aggregation type 2.5 3.0 5.8 10.6 0.9 Dowa G-35

(B) organic vehicle

(B11) Binder: Cresol novolac series (YDCN-90P) manufactured by Kukdo Chemical was used.

(B12) Binder: Bisphenol F series (YDF-170) manufactured by Kukdo Chemical was used.

(B2) Diluent: An epoxy acrylate series (EA-5521) manufactured by Shin-Nakamura was used.

(B3) Solvent: BCA (butyl cabitol acetate) was used.

(C) Curing agent: 2-undecylimidazole (product name: C11Z) manufactured by SHIKOKU Chemical was used.

Example   1-3 and Comparative example  1-3

The conductive powder was added in the composition shown in Table 2 below, and based on 100 parts by weight of the conductive powder, 2 parts by weight of (B11) binder, 2.6 parts by weight of (B12) binder, 2 parts by weight of (B2) diluent, and 3 parts by weight of solvent (B3) And (C) 0.3 parts by weight of the curing agent was added and mixed evenly to prepare a conductive paste.

Conductive powder (Ⅰ) plate type (Ii) spherical (Iv) aggregation type Example 1 40 10 50 Example 2 60 10 30 Example 3 80 10 10 Comparative Example 1 100 - - Comparative Example 2 - - 100 Comparative Example 3 - 100 -

The conductive pastes prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were coated by rolling with a scraper on the screen plate, and then printed by discharging them into the wire portion of the screen plate with a squeeze, which was cured at 200 ° C. for 40 minutes. The next electrode was formed. The electrical conductivity of the formed electrode pattern is shown in Table 3 by measuring the resistance of the electrode using a multimeter, and then measuring the area of the electrode using a 3D microscope and converting it into a specific resistance. The pattern used was 100 μm line width and the pattern length was 10 cm. In addition, in order to perform the adhesion test was printed on ITO glass using the paste and then cross-cutting the print pattern to 1 mm using the ASTM standard, the adhesion test was performed, the results are shown in Table 3.

All 100 cells formed by the printed positive electrode were attached, and the adhesion was excellent.

Wire resistance Resistivity Adhesion Example 1 57.5 2.5 × 10 ^-5 Great Example 2 48.2 1.2 × 10 ^-5 Great Example 3 50.4 1.5 × 10 ^-5 Great Comparative Example 1 60 3 × 10 ^-5 Great Comparative Example 2 Not printable - Great Comparative Example 3 90 9 × 10 ^-5 Great

As shown in Table 3, it can be seen that the paste of the present invention has excellent conductivity and adhesion by using three different types of conductive powders.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings and tables, the present invention is not limited to the above embodiments, but may be manufactured in various forms, and common knowledge in the art to which the present invention pertains. Those skilled in the art can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (13)

A conductive paste comprising a conductive powder and an organic vehicle, wherein the conductive powder is a mixture of (iii) plate-shaped powder, (ii) spherical powder and (iii) agglomerated powder.
The method of claim 1, wherein the conductive powder is silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), With tin (Sn), lead (Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo) and nickel (Nickel) A conductive paste, which is at least one selected from the group consisting of two or more alloys thereof.
The conductive powder of claim 1, wherein the conductive powder comprises (30) 30 to 90% by weight of a plate-shaped powder, (ii) 1 to 30% by weight of a spherical powder, and 1 to 60% by weight of (i) agglomerated powder. Paste.
The said (iii) plate-shaped powder is 0.5-5 micrometers in average particle diameter, The said (ii) spherical powder has an average particle diameter (D50) of 0.1-3 micrometers, The said (iii) aggregation type Conductive paste, characterized in that the powder has an average particle diameter (D50) of 1 to 10 ㎛.
The method of claim 1, wherein the (iii) plate-shaped powder has an average particle diameter (D90) of 2 to 8 ㎛, the (ii) spherical powder has an average particle diameter (D90) of 0.5 to 5 ㎛, The powder is a conductive paste, characterized in that the average particle diameter (D90) is 5 to 15 ㎛.
The conductive paste of claim 1, wherein the (i) agglomerated powder has a specific surface area of 0.5 to 5 m ² / g and a tap density of 0.5 to 4.5 g / cm ³ .
The conductive paste of claim 1, wherein the conductive paste further comprises a glass frit.
The conductive paste of claim 1, wherein the conductive paste comprises 2 to 30 parts by weight of an organic vehicle based on 100 parts by weight of the conductive powder.
The conductive paste of claim 1, wherein the organic vehicle comprises an organic binder, a diluent, and a solvent.
The conductive paste of claim 9, wherein the organic vehicle comprises 0.5 to 15 parts by weight of the organic binder, 0.5 to 5 parts by weight of the diluent and 1 to 10 parts by weight of the solvent, based on 100 parts by weight of the conductive powder.
The conductive paste of claim 1, wherein the conductive paste further comprises at least one selected from the group consisting of aluminum oxide, antimony oxide, zinc oxide, lead oxide, and copper oxide.
The method of claim 1, wherein the conductive paste further comprises at least one additive selected from the group consisting of a curing agent, a dispersant, a thixotropic agent, a viscosity stabilizer, an antifoaming agent, a pigment, an ultraviolet stabilizer, an antioxidant, an inorganic filler, and a coupling agent. A conductive paste characterized by the above.
An electrode formed from the conductive paste according to claim 1.

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