CN112642316A

CN112642316A - Method for improving dispersibility of electronic paste of photovoltaic panel

Info

Publication number: CN112642316A
Application number: CN202011529639.0A
Authority: CN
Inventors: 廖健淞; 陈庆; 司文彬; 白涛
Original assignee: Chengdu New Keli Chemical Science Co Ltd
Current assignee: Chengdu New Keli Chemical Science Co Ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2021-04-13

Abstract

The invention relates to the technical field of electronic paste, and discloses a method for improving the dispersibility of photovoltaic panel electronic paste. The p-toluenesulfonyl hydrazide can be hydrolyzed on the surface of the nano-copper micro-agglomerates to generate countless small bubbles to break the micro-agglomerates and fully disperse the micro-agglomerates, and the generated sodium p-toluenesulfonate can also promote the slurry to fully infiltrate the nano-copper particles, so that the problem of agglomeration of the filler micro-agglomerates which is difficult to solve by the traditional mechanical stirring and ball milling is effectively solved, and the uniform and stable dispersion of the conductive phase in the electronic slurry is realized.

Description

Method for improving dispersibility of electronic paste of photovoltaic panel

Technical Field

The invention relates to the technical field of electronic paste, in particular to a method for improving the dispersibility of electronic paste of a photovoltaic panel.

Background

With the rapid development of microelectronic technology, electronic devices are increasingly developed in the direction of miniaturization, integration and high frequency. The electronic paste is a mixed system of solid particles and organic liquid, wherein the solid particles are composed of functional fillers, inorganic fillers or high molecular adhesives suspended in an organic carrier. The fluid material is applied to electronic components in printing and other modes to form a module with a specific electrical function, and is a basic material of various electronic components such as integrated circuits, chip components, photovoltaic devices, flexible batteries, transistors and the like. The photovoltaic cell panel is used for directly converting solar energy into electric energy, mainly based on semiconductor materials, and generates a photovoltaic effect after photoelectric materials absorb the solar energy. For a photovoltaic panel, in order to output electric energy, a conductive material which forms close ohmic contact with two ends of a P-N junction of a cell must be manufactured on a photovoltaic cell as a positive electrode and a negative electrode, which are called as an upper electrode and a lower electrode, and the upper electrode and the lower electrode are generally prepared by screen printing thick film electronic paste.

In the configuration of the electronic paste, a part of inorganic adhesive and organic carrier are uniformly mixed, dispersed and coated and sintered through higher content of functional filler phase to obtain a functional film with a specific shape or effect, and the key points are selection, dispersion and molding of the functional filler. In the sintering process of the slurry after film formation, large particles are easy to appear in the slurry due to the agglomeration of the functional filler, so that the stress distribution of the formed film material is uneven, cracks, air holes and the like appear on the surface of the formed film material, and the quality and the conductive capability of the film material are greatly influenced.

Most of the traditional methods for solving the problem of dispersion of the functional filler by the electronic paste are to use a dispersing agent or a special mixing process, and the mutual exclusion capability of the functional filler particles is improved by means of coating, loading, mixing and the like of the dispersing agent on the functional filler, so that the dispersion performance of the functional filler is improved. Patent CN106448803A provides a back contact solar cell hole-filling electronic paste and a production method thereof, the main components are metal particles, glass powder, organic solvent, dispersant and surfactant, and the paste is characterized in that the paste comprises the following components by weight percent: 85-95% of metal particles, 2-6% of glass powder, 2-7% of organic solvent, 0.5-1% of dispersant and 0.5-1% of surfactant, wherein the dispersant and the surfactant are added to improve the dispersibility of the slurry. Patent CN106952675B proposes a graphene-based organic carrier and a preparation method thereof, an electronic paste and a preparation method thereof, wherein the graphene-based organic carrier comprises the following components by mass percent: the organic carrier is characterized by comprising, by weight, 80% -95% of an organic solvent, 1% -10% of a thixotropic agent, 1% -6% of a plasticizer, 1% -6% of a binder and 0.01% -0.14% of functional graphene, wherein the functional treated graphene is added into a traditional organic carrier, the graphene is assembled into a spatial network structure in the organic solvent by utilizing the lubricity of a two-dimensional structure of the graphene, and a small amount of organic substances such as the thixotropic agent and the like are added on the basis, so that the finally prepared organic carrier has good leveling property and thixotropy, the dispersibility of silver particles in the organic carrier can be improved, and the electrical conductivity and the thermal conductivity of the electronic paste are improved. Patent CN108538443A proposes an organic carrier for solar energy electronic paste and an electronic paste containing the organic carrier, which is prepared by adding a polymer carrier with good dispersibility and stirring for many times at different temperatures during the preparation process of the paste to improve the fluidity of the paste and the dispersibility of particles. Patent CN205216653U proposes a dispersing device for electronic paste, which reduces dust of functional filler and improves the uniformity of particle dispersion by high speed rotation. However, these methods are not particularly preferable for the dispersion effect of the conductive filler, and the particle size of the functional filler in the slurry after dispersion is large, and it is difficult to effectively control the particle size to 10 μm or less, and particularly, it is difficult to effectively break the agglomerated particles, and there is a large loss in functionality after the slurry is formed into a film. Therefore, effective dispersion of the functional filler in the electronic paste is a very important control link in the electronic paste configuration.

Disclosure of Invention

The invention provides a method for improving the dispersibility of electronic paste of a photovoltaic panel, aiming at the problems that the existing electronic paste has more conductive filler content and is easy to agglomerate in the paste preparation process to cause poor film material performance. The foaming agent is agglomerated on the surface of the conductive phase particles and continuously generates bubbles, the bubbles are burst and the gas driving force generated by the bubbles promotes the dispersion of the small lumps which are difficult to be successfully dispersed in the conductive phase by a common dispersion method, so that the phenomena of film material balling and uneven surface caused by the small lumps in the sintering process are effectively solved.

A method for improving the dispersibility of electronic paste of a photovoltaic panel is characterized by comprising the following preparation steps:

(1) dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 10-15% of the solution, and stirring until the solution forms viscous slurry;

(2) adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for a period of time at the temperature of 60-65 ℃ to form suspended slurry of nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:2-6:21-35: 0.6-1.8;

(3) dropwise adding dilute hydrochloric acid into the suspended slurry obtained in the step (2) until the suspended slurry is neutral, then adding p-toluenesulfonyl hydrazide in an amount of 2% -3% of the mass of the suspended slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for a period of time under an inert atmosphere, stirring, mixing and preserving heat, and dropwise adding a saturated sodium carbonate solution in an amount of 1% of the mass of the suspended slurry to obtain a uniformly dispersed mixture without nano-copper micro-agglomerates; the p-toluenesulfonyl hydrazide powder is suspended and agglomerated on the surface of a nano copper particle and is explained to release nitrogen in hot water, countless small bubbles are exploded and cracked on the surface of a nano copper micro block at the same time, and the micro block formed by the agglomeration of the nano copper is dispersed by the driving force formed by airflow, so that the dispersing effect of crushing the micro block which is difficult to achieve by pure mechanical stirring and ball milling is achieved;

(4) and (4) uniformly mixing the mixture obtained in the step (3), glass powder and an organic carrier according to a certain mass ratio, and fully stirring to form slurry with good dispersibility.

Preferably, polyacrylamide powder with the mass of 12% of the solution is added in the step (1).

Preferably, the reaction is stirred in the step (2) for 20-30min, so that higher yield can be achieved, and the yield is not obviously increased along with the continuous prolonging of the reaction time.

Preferably, the concentration of the dilute hydrochloric acid in the step (3) is 0.1-0.2 mol/L.

Preferably, p-toluenesulfonyl hydrazide is added in step (3) in an amount of 2% to 2.5% by weight of the suspended slurry.

Preferably, the stirring and heat preservation time in the step (3) is 30-40 min.

Preferably, the stirring and heat-insulating in step (3) are performed under a nitrogen atmosphere.

Preferably, in the step (4), the mixture obtained in the step (3) is uniformly mixed with the glass powder and the organic carrier according to the mass ratio of 75:5: 20.

Preferably, the organic carrier in the step (4) comprises 86-90 parts by mass of N-methyl pyrrolidone, 3.2-5 parts by mass of sodium dodecyl benzene sulfonate, 2-4.5 parts by mass of ethyl cellulose, 1-7 parts by mass of cellulose acetate butyrate and 3.4-5 parts by mass of phenolic aldehyde or polyaldehyde resin.

Hydrazine hydrate is used as a reducing agent to reduce bivalent copper ions under an alkaline condition to generate nano copper particles, p-toluenesulfonyl hydrazide is agglomerated on nano copper micro agglomerates, nitrogen is decomposed in hot water to generate countless micro bubbles, the countless micro bubbles are burst and the gas driving force generated by the bubbles promotes the micro agglomerates formed by agglomeration of the nano copper particles to be dispersed and fully infiltrated, p-toluenesulfonyl hydrazide is decomposed to generate sodium p-toluenesulfonate which is a good surfactant and can promote slurry to effectively infiltrate the nano copper particles, the p-toluenesulfonyl hydrazide can be hydrolyzed on the surfaces of the nano copper micro agglomerates to generate countless micro bubbles to break the micro agglomerates and fully disperse the micro agglomerates, and the generated sodium p-toluenesulfonate can also promote the slurry to fully infiltrate the nano copper particles, so that the problem that the filler micro agglomerates are agglomerated and are difficult to solve by traditional mechanical stirring and ball milling is effectively solved, thereby realizing the uniform and stable dispersion of the conductive phase in the electronic paste.

Has the advantages that:

the p-toluenesulfonyl hydrazide generates countless micro bubbles on the surface of the nano-copper micro agglomerate and explodes the micro bubbles to crack, the formed airflow driving force can effectively crush and disperse the nano-copper particles gathered in the micro agglomerate, and the sodium p-toluenesulfonate generated by the reaction of the p-toluenesulfonyl hydrazide is a good surfactant, so that the slurry can be promoted to fully infiltrate the nano-copper particles, the effect of uniform and stable dispersion of the nano-copper in the slurry is achieved, and the influence of the micro agglomerate on the quality of the film material in the coating and sintering processes is inhibited.

Drawings

FIG. 1 is a graph of the time for settling upon standing in example 1, a: natural sedimentation for 30min, b: naturally settling for 120 min;

fig. 2 is a graph comparing the time of settling upon standing of comparative example 1, c: natural sedimentation for 30min, d: naturally settling for 120 min.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.

Example 1

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 10% of the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 20min at 60 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:2:21: 0.6. Dropwise adding 0.1mol/L dilute hydrochloric acid into the suspension slurry until the suspension slurry is neutral, then adding p-toluenesulfonyl hydrazide according to 2% of the mass of the suspension slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for 30min, stirring and mixing uniformly, and dropwise adding a saturated sodium carbonate solution according to 1% of the mass of the suspension slurry while preserving heat to obtain a uniformly dispersed mixture without nano-copper micro agglomerates. The mixture is uniformly mixed with glass powder and an organic carrier according to the mass ratio of 75:5:20, and the mixture is fully stirred to form slurry with good dispersibility, wherein the organic carrier comprises 86 parts of N-methyl pyrrolidone, 3.2 parts of sodium dodecyl benzene sulfonate, 2 parts of ethyl cellulose, 1 part of cellulose acetate butyrate and 3.4 parts of phenolic aldehyde or polyaldehyde resin.

Example 2

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding 11% by mass of polyacrylamide powder into the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 20min at 63 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:3:23: 0.9. Dropwise adding 0.1mol/L dilute hydrochloric acid into the suspension slurry until the suspension slurry is neutral, then adding p-toluenesulfonyl hydrazide according to 2% of the mass of the suspension slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for 30min, stirring and mixing uniformly, and dropwise adding a saturated sodium carbonate solution according to 1% of the mass of the suspension slurry while preserving heat to obtain a uniformly dispersed mixture without nano-copper micro agglomerates. The mixture is uniformly mixed with glass powder and an organic carrier according to the mass ratio of 75:5:20, and the mixture is fully stirred to form slurry with good dispersibility, wherein the organic carrier comprises 87 parts by mass of N-methyl pyrrolidone, 3.8 parts by mass of sodium dodecyl benzene sulfonate, 2 parts by mass of ethyl cellulose, 3 parts by mass of cellulose acetate butyrate and 4 parts by mass of phenolic aldehyde or polyaldehyde resin.

Example 3

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 13% of the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 25min at 65 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:4:27: 1.3. Dropwise adding 0.1mol/L dilute hydrochloric acid into the suspension until the suspension is neutral, then adding p-toluenesulfonyl hydrazide in an amount of 2.5% of the mass of the suspension, stirring and mixing uniformly, heating to 80 ℃, stirring and keeping the temperature for 35min, stirring, mixing and keeping the temperature, and dropwise adding a saturated sodium carbonate solution in an amount of 1% of the mass of the suspension, thereby obtaining a uniformly dispersed mixture without nano-copper micro agglomerates. The mixture is uniformly mixed with glass powder and an organic carrier according to the mass ratio of 75:5:20, and the mixture is fully stirred to form slurry with good dispersibility, wherein the organic carrier comprises 88 parts of N-methyl pyrrolidone, 4.5 parts of sodium dodecyl benzene sulfonate, 3 parts of ethyl cellulose, 5 parts of cellulose acetate butyrate and 4.5 parts of phenolic aldehyde or polyaldehyde resin.

Example 4

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 14% of the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 30min at 65 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:5:32: 1.5. Dropwise adding 0.2mol/L dilute hydrochloric acid into the suspension slurry until the suspension slurry is neutral, then adding p-toluenesulfonyl hydrazide according to 3% of the mass of the suspension slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for 35min, stirring, mixing and preserving heat, and dropwise adding a saturated sodium carbonate solution according to 1% of the mass of the suspension slurry to obtain a uniformly dispersed mixture without nano-copper micro agglomerates. The mixture is uniformly mixed with glass powder and an organic carrier according to the mass ratio of 75:5:20, and the mixture is fully stirred to form slurry with good dispersibility, wherein the organic carrier comprises 89 parts of N-methyl pyrrolidone, 5 parts of sodium dodecyl benzene sulfonate, 3 parts of ethyl cellulose, 6 parts of cellulose acetate butyrate and 5 parts of phenolic aldehyde or polyaldehyde resin.

Example 5

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 15% of the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 30min at 65 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:6:35: 1.8. Dropwise adding 0.2mol/L dilute hydrochloric acid into the suspension slurry until the suspension slurry is neutral, then adding p-toluenesulfonyl hydrazide according to 3% of the mass of the suspension slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for 40min, stirring and mixing uniformly, and dropwise adding a saturated sodium carbonate solution according to 1% of the mass of the suspension slurry while preserving heat to obtain a uniformly dispersed mixture without nano-copper micro agglomerates. The mixture is uniformly mixed with glass powder and an organic carrier according to the mass ratio of 75:5:20, and the mixture is fully stirred to form slurry with good dispersibility, wherein the organic carrier comprises 90 parts of N-methyl pyrrolidone, 5 parts of sodium dodecyl benzene sulfonate, 4.5 parts of ethyl cellulose, 7 parts of cellulose acetate butyrate and 4.5 parts of phenolic aldehyde or polyaldehyde resin.

Comparative example 1

Dissolving copper acetate in deionized water to prepare a 0.2mol/L solution, slowly adding polyacrylamide powder with the mass of 10% of the solution, and stirring until the solution forms viscous slurry. Adding hydrazine hydrate, ammonia water and EDTA into the viscous slurry, stirring and reacting for 20min at 60 ℃ to form suspended slurry of the nano copper particles, wherein the mass ratio of the viscous slurry, the hydrazine hydrate with the concentration of 85 percent, the ammonia water with the concentration of 10 percent and the EDTA is 100:2:21: 0.6. 0.1mol/L dilute hydrochloric acid is added into the suspension until the suspension is neutral. And then uniformly mixing the suspension slurry with sodium p-toluenesulfonate, glass powder and an organic carrier according to a mass ratio of 75:2:5:20, and fully stirring to form slurry, wherein the organic carrier comprises 86 parts of N-methylpyrrolidone, 3.2 parts of sodium dodecyl benzene sulfonate, 2 parts of ethyl cellulose, 1 part of cellulose acetate butyrate and 3.4 parts of phenolic aldehyde or polyaldehyde resin.

And (3) correlation detection:

5g of the electronic paste obtained in example 1 was stirred in 80ml of deionized water to disperse the zeta potential of the test solution, and natural sedimentation was observed for 2 hours, and the test results are shown in Table 1.5 g of the electronic paste in comparative example 1 was taken, and the zeta potential of the test solution was dispersed by stirring in 80ml of deionized water, and the natural settling was observed for 2 hours, and the test results are shown in Table 1.

TABLE 1

	zeta potential
		Example 1	-57±5
Example 2	-55±4
		Example 3	-59±4
Example 4	-58±2
		Example 5	-60±6
Comparative example 1	-34±3

Through detection, the absolute value of the zeta potential of the electronic paste prepared in the embodiment of the invention dispersed in water is higher, which shows that the sample prepared in the embodiment has stronger dispersibility and dispersion stability, and the sodium p-toluenesulfonyl hydrazide generates a sodium p-toluenesulfonate surfactant on the surface of the nano copper while generating bubbles to break the nano copper micro-agglomerates through hydrolysis, so that the dispersibility and the dispersion stability of the conductive filler in the paste are improved. In comparative example 1, although the surfactant was used, the conductive filler powder in comparative example 1 had a large number of fine agglomerates which were not broken, the interiors of the fine agglomerates were not sufficiently wetted with the slurry, and the dispersibility and dispersion stability of the conductive filler were inferior to those of the p-toluenesulfonyl hydrazide-treated samples in examples. As shown in fig. 1b, the electronic paste in example 1 undergoes natural sedimentation for 2 hours without obvious sedimentation delamination, and as shown in fig. 2d, the untreated nano-copper powder in comparative example 1 undergoes obvious delamination after natural sedimentation for 2 hours, because the nano-copper powder in comparative example 1 has a tiny agglomerate, the surfactant cannot enter the inside of the agglomerate, the inside of the agglomerate cannot be sufficiently infiltrated by the paste and further cannot be effectively dispersed, and the conductive powder is more easily sedimented due to the existence of a large amount of the agglomerate, so that delamination occurs.

Claims

1. A method for improving the dispersibility of electronic paste of a photovoltaic panel is characterized by comprising the following preparation steps:

(3) dropwise adding dilute hydrochloric acid into the suspended slurry obtained in the step (2) until the suspended slurry is neutral, then adding p-toluenesulfonyl hydrazide in an amount of 2% -3% of the mass of the suspended slurry, stirring and mixing uniformly, heating to 80 ℃, stirring and preserving heat for a period of time under an inert atmosphere, stirring, mixing and preserving heat, and dropwise adding a saturated sodium carbonate solution in an amount of 1% of the mass of the suspended slurry to obtain a uniformly dispersed mixture without nano-copper micro-agglomerates;

2. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: polyacrylamide powder with the mass of 12% of the solution is added in the step (1).

3. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: and (3) stirring and reacting for 20-30min in the step (2).

4. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: the concentration of the dilute hydrochloric acid in the step (3) is 0.1-0.2 mol/L.

5. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: in the step (3), p-toluenesulfonyl hydrazide is added according to 2-2.5% of the mass of the suspension slurry.

6. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: and (4) stirring and preserving heat for 30-40min in the step (3).

7. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: the stirring and heat preservation in the step (3) are carried out in a nitrogen atmosphere.

8. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: in the step (4), the mixture obtained in the step (3) is uniformly mixed with the glass powder and the organic carrier according to the mass ratio of 75:5: 20.

9. The method for improving the dispersibility of the electronic paste of the photovoltaic panel according to claim 1, wherein: in the step (4), the organic carrier comprises 86-90 parts by mass of N-methyl pyrrolidone, 3.2-5 parts by mass of sodium dodecyl benzene sulfonate, 2-4.5 parts by mass of ethyl cellulose, 1-7 parts by mass of cellulose acetate butyrate and 3.4-5 parts by mass of phenolic aldehyde or polyaldehyde resin.