CN114974655A

CN114974655A - Organic vehicle, conductive paste and solar cell

Info

Publication number: CN114974655A
Application number: CN202210602700.2A
Authority: CN
Inventors: 孙丰振; 李德林
Original assignee: Soltrium Advanced Materials Technology Ltd Shenzhen
Current assignee: Soltrium Advanced Materials Technology Ltd Shenzhen
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-08-30

Abstract

The application relates to the technical field of batteries, in particular to an organic carrier, conductive paste and a solar battery. The application provides an organic carrier in a first aspect, which comprises the following raw materials in parts by weight: 1-5 parts of a resin matrix; 0.01-5 parts of a silane coupling agent; 0.1-5 parts of a curing agent; 0.01-1 part of an initiator; 0.01-10 parts of an auxiliary agent; wherein the silane coupling agent contains epoxy groups. According to the organic carrier, the organic carrier is formed by compounding the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent, the resin matrix can be modified through the silane coupling agent, the resin matrix is used as a matrix material, the silane coupling agent is distributed in the matrix material, the silane coupling agent can be hydrolyzed in advance, the hydrolyzed silane coupling agent can have more exposed hydroxyl groups, and then more hydrogen bonds are formed with the substrate, so that the adhesive force of the organic carrier is enhanced.

Description

Organic vehicle, conductive paste and solar cell

Technical Field

The application belongs to the technical field of silver paste, and particularly relates to an organic carrier, conductive paste and a solar cell.

Background

Solar energy is one of new energy, has small geographical limitation, is clean and safe, is inexhaustible, and is very ideal renewable energy. With the continuous progress of photovoltaic technology and the continuous reduction of installation cost driven by industrial upgrading, the vision of realizing flat price on line is no longer luxurious, countries continuously promote the development of carbon neutralization in recent years, photovoltaic energy is used as new energy with the most cost and environmental advantages, the growth space is huge, with the trend of epidemic situation, the global market is gradually recovered, the carbon peak-reaching and carbon neutralization targets proposed in China must be realized, in the middle and long term, the space for the growth of photovoltaics in China is very large, and the quantity of photovoltaic installations is greatly increased.

However, due to the self-defect of the P-type cell technology, namely attenuation problem, efficiency technology is slowly updated, and development of a high-efficiency solar cell is urgently needed, while the HJT heterojunction solar cell has inherent advantages, and the market occupation ratio thereof is increased year by year.

The symmetrical structure of the HJT battery reduces the process equipment and steps; the TCO film deposited on the surface can resist the temperature of 200 ℃ at most, so that the high-temperature sintering of the traditional crystalline silicon solar cell is avoided, the energy is saved, meanwhile, the heat damage and the deformation of the silicon wafer are reduced by a low-temperature process, and the flaking is easier to realize than that of the traditional crystalline silicon cell; because the intrinsic thin film is inserted between the crystalline silicon and the doped thin film in the HJT cell, the defects on the surface of the crystalline silicon are effectively passivated, and the open-circuit voltage higher than that of a conventional cell can be obtained; in addition, the HJT battery also has excellent temperature characteristics, and has higher output power than a conventional battery in the outdoor illumination heating process; meanwhile, the HJT battery has good illumination stability and almost has no light-induced attenuation problem.

However, as many related technical problems of HJT are not effectively solved, the manufacturing cost is high, and the rapid development process of the HJT is limited, wherein the HJT conductive silver paste comprises conductive silver paste for the HJT, the development of domestic HJT slurry is slow, the research and development time is relatively short, the technical accumulation is less, the requirement on the HJT slurry is high, and the technical difficulties are more; high conductivity and strong adhesion and weather resistance are required while maintaining the printing smoothness of the paste.

Disclosure of Invention

An object to prior art this application provides an organic carrier, conductive paste and solar cell, aims at solving the poor problem of current silver thick liquid electric conductivity, adhesion, weatherability, printing smoothness nature.

In order to achieve the purpose of the application, the technical scheme adopted by the application is as follows:

the first aspect of the embodiments of the present application provides an organic vehicle, which includes the following raw materials by weight:

wherein the silane coupling agent contains epoxy groups.

The integral performance of the organic carrier can be adjusted by regulating and controlling the compound ratio of the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent.

According to the organic carrier, the organic carrier is formed by compounding the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent, the resin matrix can be modified through the silane coupling agent, the resin matrix is used as a matrix material, the silane coupling agent is distributed in the matrix material, the silane coupling agent can be hydrolyzed in advance, the hydrolyzed silane coupling agent can have more exposed hydroxyl groups, and then more hydrogen bonds are formed with the substrate, so that the adhesive force of the organic carrier is enhanced.

The curing agent and the initiator can initiate the resin matrix to be cured, and the auxiliary agent can endow the organic carrier with other properties.

In a second aspect, the present application provides a method for preparing an organic vehicle, comprising the steps of:

the preparation method comprises the step of mixing the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent to obtain the organic carrier.

According to the application, the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent are mixed, and at the moment, the silane coupling agent, the resin matrix and the curing agent do not have a curing reaction, so that the subsequent curing treatment and coating treatment are facilitated.

In a third aspect, the present application provides a conductive paste comprising a mixture of the organic vehicle and the conductive agent described herein above.

According to the conductive paste formed by compounding the organic carrier and the conductive agent, the conductive agent endows the conductive paste with conductive performance, and the conductive agent is dispersed in the organic carrier, so that the conductive paste is conveniently subjected to coating treatment to form a conductive layer. The integral performance of the organic carrier can be adjusted by regulating and controlling the compound ratio of the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent. Such as improved printing and conductive properties of the conductive paste, increased aspect ratio and lower wet weight.

A fourth aspect of the embodiments of the present application provides a method for preparing conductive paste, including the following steps:

the organic vehicle and the conductive agent, including those described above, are mixed to obtain a mixture.

In the embodiment of the present application, the organic vehicle and the conductive agent in the embodiment of the present application are mixed, so that the organic vehicle and the conductive agent are mixed with each other, and a conductive paste with excellent printing performance and conductive performance is obtained.

In a fifth aspect of the embodiments of the present application, there is provided a solar cell, including a substrate and an electrode bonded on the substrate, wherein the electrode is formed by curing a conductive paste including the conductive paste described above or prepared by the method for preparing the conductive paste described above.

The solar cell comprises an HIT solar cell, and comprises a substrate and an electrode combined on the substrate, wherein the electrode is a conductive layer formed by curing the conductive paste comprising the conductive paste or the conductive paste prepared by the preparation method of the conductive paste, the conductive paste is cured, under the conditions of an initiator and a curing agent, a resin matrix and a silane coupling agent in an organic carrier are cured to form a three-dimensional network structure, the conductive agent is dispersed in the conductive paste, and in the curing process, organic matters on the surface of the conductive agent are decomposed to form a conductive path, so that the conductivity of the solar cell is increased.

Drawings

Fig. 1 is a schematic structural diagram of a first conductive agent according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a second conductive agent according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a third conductive agent according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a fourth conductive agent according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a resistivity pattern provided by an embodiment of the invention;

FIG. 6 is a schematic diagram of a screen according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of another screen pattern according to an embodiment of the present invention;

fig. 8 is a flowchart of a conductive paste preparation method according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In this application, the term "and/or" describes an association relationship of associated objects, which means that there may be three relationships, for example, a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In the present application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one item(s) of a, b, or c," or "at least one item(s) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.

It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The weight of the related components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present application as long as it is scaled up or down according to the description of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application may be a mass unit known in the chemical industry field such as μ g, mg, g, kg, etc.

The terms first and second are used for descriptive purposes only and are used for distinguishing one object, such as a substance, from another object, and are not to be construed as indicating or implying relative importance or to imply that the number of technical features indicated is significant. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of regulations of this application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

wherein the silane coupling agent contains epoxy groups.

In a first aspect, the overall performance of the organic vehicle can be adjusted by adjusting and controlling the compound ratio of the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent. For example to adjust the printing properties of the organic vehicle. In the second aspect, the organic carrier is formed by compounding a resin matrix, a silane coupling agent, a curing agent, an initiator and an auxiliary agent, the resin matrix can be modified by the silane coupling agent, the resin matrix is used as a matrix material, and the silane coupling agent is distributed in the matrix material, wherein an epoxy group in the silane coupling agent and the resin matrix are cured together, so that the flexibility of the reaction curing film is improved, and the contractibility of the curing film during curing is improved. In a third aspect, the curing agent and initiator are capable of initiating the curing of the resin matrix, and the adjuvant is capable of imparting other properties to the organic vehicle.

In some embodiments, the material forming the resin matrix comprises an epoxy or modified epoxy. Herein, the epoxy resin includes at least one of hydrogenated epoxy resin, novolac epoxy resin, alicyclic epoxy resin, and aliphatic epoxy resin. Herein, the modified epoxy resin includes at least one of a urethane-modified epoxy resin, an acrylic-modified epoxy resin, and a polyester-modified epoxy resin. Herein, the weight component of the resin matrix may be 3.07 parts, 2.07 parts, 3.2 parts, 1.5 parts.

In some embodiments, the silane coupling agent includes Y _n SiX ₃ ，Y _n SiX ₃ Wherein Y contains epoxy group and X contains alkoxy group. In some embodiments, the silane coupling agent with an epoxy group is an organosilicon compound containing two different chemistries simultaneously, YnSiX ₃ Y is an epoxy group and can not be hydrolyzed, but participates in the reactive group of epoxy resin in the conductive silver paste for HIT (high conductivity and low contact resistance), the flexibility of a reaction curing film is improved, the contractibility of the curing film during curing is improved, the contact gap of conductive metal powder is reduced, the tunneling resistance is reduced, the electrical performance is further improved, the X group is a group which can generate good bonding force with a substrate more easily, the X group can be hydrolyzed in advance, the hydrolyzed silane coupling agent can have more exposed hydroxyl groups, and further more exposed hydroxyl groups are formed with the substrateHydrogen bonding, enhancing the adhesion of the organic vehicle. In the above context alkoxy groups include-OCH ₃ 、-OC ₂ H ₅ 、-OCOCH ₃ 、-OCH ₂ CH ₂ OCH ₃ At least one of the above groups can be hydrolyzed, and Si-OH groups generated by hydrolysis can generate more excellent bonding force with the substrate and more excellent corrosion resistance. Herein above, the silane coupling agent may be present in an amount of 0.93 parts by weight or 0.5 parts by weight.

In some embodiments, the curing agent comprises at least one of methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, anhydride No. 70, phthalic anhydride, hexahydrophthalic anhydride, diphenyl ether tetracarboxylic dianhydride. The weight components of the curing agent can be 1 part and 0.23 part.

In some embodiments, to improve the timing of the initiator action and improve the storage stability of the organic vehicle, the initiator is a latent cationic thermal initiator, and the latent cationic thermal initiator comprises at least one of a blocked phosphate cationic initiator, a blocked sulfonium salt cationic initiator, and a boron-amine cationic initiator. Herein, the weight component of the initiator may be 0.02 parts, 0.14 parts, but is not limited thereto.

In some embodiments, to improve the adhesion of the organic vehicle, the adjuvant includes an adhesion promoter. As used herein, the adhesion promoter includes at least one of modified phosphate ester compounds, phthalate ester compounds, polyester-modified phosphate esters, epoxy-modified multifunctional phosphate esters, n-butyl titanate, and titanium acetylacetonate chelates. Herein above, the adhesion promoter may be 0.05 parts by weight, but is not limited thereto.

In some embodiments, to improve the viscosity of the organic vehicle, and to improve printing performance, the adjuvant includes a non-reactive diluent. Herein above, the non-reactive diluent comprises at least one of alcohol ester 12, diethylene glycol butyl ether acetate, tributyl citrate, terpineol, DBE. As used herein, the weight fraction of the non-reactive diluent may be 1 part, 1.3 parts, 3 parts.

In some embodiments, to improve dispersion among the resin matrix, silane coupling agent, curing agent, initiator, and coagent, the coagent includes an agent containing acidic groups. As described above, the agent having an acidic group includes at least one of oleic acid, TDO dispersant, acrylic dispersant, and modified polyester dispersant. Here, the weight component of the acidic group-containing agent may be 1.1 parts, 0.46 parts, 0.54 parts, 1.1 parts but is not limited thereto.

In a second aspect, the embodiment of the present application provides a method for preparing an organic vehicle, including the following steps:

step S10: the preparation method comprises the step of mixing the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent to obtain the organic carrier.

According to the embodiment of the application, the resin matrix, the silane coupling agent, the curing agent, the initiator and the auxiliary agent are mixed, and at the moment, the silane coupling agent, the resin matrix and the curing agent do not have a curing reaction, so that the subsequent curing treatment and coating treatment are facilitated.

In step S10, the method further includes a step of hydrolyzing the silane coupling agent to obtain a hydrolyzed silane coupling agent, before the mixing step. In the above, the hydrolysis treatment specifically comprises the following steps:

and mixing the silane coupling agent and the solvent, adjusting the pH value to 4.5-5.5, and heating to 50-70 ℃ to hydrolyze the silane coupling agent.

In some embodiments, in order to improve the dispersity between the auxiliary agent and the initiator, the method further comprises the step of performing pre-dispersion treatment on the auxiliary agent and the initiator to obtain a pre-dispersion.

In a third aspect of the embodiments herein, there is provided a conductive paste comprising a mixture of the organic vehicle and the conductive agent described above.

In the conductive paste formed by compounding the organic carrier and the conductive agent provided by the embodiment of the application, the conductive agent endows the conductive paste with conductive performance, and the conductive agent is dispersed in the organic carrier, so that the conductive paste is conveniently coated to form a conductive layer.

In some embodiments, the weight ratio of the organic carrier to the conductive agent is 88-94: 18-6. In the whole conductive paste component, the system viscosity can be adjusted by adjusting the proportion of the organic carrier and the conductive agent, so that the state of the conductive paste is not too thin or too thick, and the feasibility of paste printing can be improved.

In some embodiments, the conductive agent includes at least one of a first conductive agent, a second conductive agent, a third conductive agent, a fourth conductive agent and a fifth conductive agent, the first conductive agent includes a silver particle and an organic matter coated on the surface of the silver particle, as shown in fig. 1, the second conductive agent includes a copper particle, a silver layer coated on the surface of the copper particle and an organic matter coated on the surface of the silver layer, as shown in fig. 2, the second conductive agent includes a copper particle, a silver layer coated on the surface of the copper particle and an organic matter coated on the surface of the silver layer, as shown in fig. 3, the third conductive agent includes a copper particle, a nickel layer coated on the surface of the copper particle and a first metal layer coated on the surface of the nickel layer, as shown in fig. 4, the fourth conductive agent includes a copper particle, a second metal layer coated on the surface of the copper particle and an organic matter coated on the surface of the second metal layer, and the fifth conductive agent includes an alloy formed by at least two of tin, silver and indium. According to the first aspect, the organic matter on the surface of the conductive agent improves the dispersibility of the conductive agent in an organic carrier and prevents the conductive agent from agglomerating, and in the second aspect, the outermost layers of the first conductive agent, the second conductive agent and the fourth conductive agent are low-temperature dissociable organic matters which can be dissociated at the curing temperature (180-220 ℃) required by low-temperature silver paste so that conductive metal can be in close contact with each other better, the conductivity is improved, or the conductive metal is cleared by soldering flux in the subsequent welding process so as to be combined with soldering tin better to form a firm welding spot.

Specifically, the mass ratio of the fifth conductive agent in all the conductive agents is 0.1-2 wt%, and the fifth conductive agent comprises at least one of the following components (A), (B), (C), (D), (E) and (F).

(A) The mass ratio of In is 97% and the mass ratio of Ag is 3% based on 100% by mass of the fifth conductive agent.

(B) The In content is 52% by mass and the Sn content is 48% by mass, based on 100% by mass of the fifth conductive agent.

(C) The mass ratio of Ag is 10% and the mass ratio of In is 90% based on 100% of the mass of the fifth conductive agent.

(D) The mass ratio of Sn is 99.3% and the mass ratio of Cu is 0.7% based on 100% by mass of the fifth conductive agent.

(E) The mass ratio of Sn is 96.5%, the mass ratio of Ag is 3.0%, and the mass ratio of Cu is 0.5%, with respect to 100% by mass of the fifth conductive agent.

(F) The mass ratio of Sn is 99%, the mass ratio of Ag is 0.3%, and the mass ratio of Cu is 0.7%, based on 100% by mass of the fifth conductive agent. The melting point of the fifth conductive agent is below 230 ℃, and the fifth conductive agent can be diffused and fused with silver particles or silver-coated copper particles in a low-temperature drying stage in the electrode manufacturing process, so that the combination of the silver particles or the silver-coated copper particles is increased, and the conductivity of the fifth conductive agent is improved. In the subsequent high-temperature welding process, the fifth conductive agent can further promote the combination and the conductivity between the silver particles or the silver-coated copper particles through the diffusion of the fifth conductive agent, and forms good metallurgical combination with the soldering tin material, so that the combination force between the soldering tin material and the electrode is improved.

In some embodiments, the organic substance includes at least one of benzotriazole, copper benzotriazole, imidazole, copper imidazole, benzimidazole, and copper benzimidazole, and the organic substance provided in the embodiments of the present disclosure can uniformly disperse the conductive agent in the organic carrier, and under a certain curing condition, the organic substance can decompose to promote the conductive agent to contact with each other, thereby increasing the conductivity of the conductive paste.

In some embodiments, the first metal layer and the second metal layer are respectively and independently selected from one of silver, tin and soldering tin, and the conductivity of the conductive paste can be further improved.

In some embodiments, the shape of the conductive agent includes at least one of a ball shape, a ball-like shape, a sheet-like shape, and a dendritic shape, and is a ball shape as shown in fig. 1 to 4, but is not limited thereto.

step S40: mixing the organic carrier, the conductive agent and the solvent to obtain a first mixture;

step S50: and filtering the first mixture to obtain the conductive slurry.

The embodiment of the present application includes mixing the organic carrier, the conductive agent, and the solvent, so that the organic carrier, the conductive agent, and the solvent are mixed with each other, and then the three-roll mill is used to perform three-roll processing on the first mixture, so as to further disperse the first mixture, thereby obtaining a second mixture, and the second mixture is filtered, so as to remove impurities, thereby facilitating subsequent processing of the conductive paste.

The step S40 includes a step of preparing a conductive agent. Low temperature cleavable organic coating process: weighing 10g of low-temperature dissociable organic coating, adding the weighed 10g of low-temperature dissociable organic coating into 100g of 3% acetic acid ethanol solution for later use, then adding particles of silver, silver-coated copper or copper coated by two layers of metal into the low-temperature dissociable organic coating solution, soaking for 1min, and performing suction filtration and washing to obtain the first, second or fourth conductive agent.

In some embodiments, the metal particles of the second conductive agent are copper particles surface-coated with silver. The specific method comprises the following steps: the copper powder is ultrasonically washed by dilute acid and then prepared into copper powder suspension. Adding a reducing agent sodium hypophosphite into the copper powder suspension, adjusting the pH value to 10-11 by using sodium hydroxide, then slowly adding a silver-ammonia solution, and filtering and washing after ultrasonic stirring. And (3) drying the washed powder in an electrothermal blowing drying oven at 80 ℃ for 2 hours to obtain metal particles of a second conductive agent, and then performing a low-temperature dissociable organic coating process to obtain the second conductive agent.

In some embodiments, the third conductive agent is formed by coating two metal layers on the surfaces of copper particles, the copper powder is subjected to ultrasonic washing by using dilute acid, a nickel sulfate solution is added, the pH value is adjusted to 4-5 by using acetic acid, then a sodium hypophosphite solution is dropwise added, and filtering and washing are performed after ultrasonic stirring. Preparing the washed powder into a suspension, carrying out ultrasonic treatment at 60 ℃ for 30min, adding a reducing agent glucose, adjusting the pH value to 10-11 by using sodium hydroxide, slowly adding a silver ammonia solution, carrying out ultrasonic reaction for 30min, and then filtering and washing. And (3) putting the washed powder into an electric heating forced air drying oven to be dried for 2 hours at the temperature of 80 ℃ to obtain the third conductive agent.

In some embodiments, for improvement, the shape of the conductive agent includes at least one of a spherical shape, a spherical-like shape, a sheet-like shape, a fiber, and a dendritic shape. In the above, the conductive agent has an average particle diameter of 0.2 to 10 μm when it is in the form of at least one of a spherical form, a spheroidal form, a sheet form and a dendritic form.

step S20: the organic vehicle and the conductive agent, including those described above, are mixed to obtain a mixture.

In step S20, in order to further improve the dispersion degree among the resin matrix, the silane coupling agent, the curing agent, and the conductive agent in the conductive paste, the mixing process further includes adjustment of the feeding sequence and the mixing frequency, and therefore, the mixing process specifically includes the following steps:

carrying out first mixing treatment on part of the auxiliary agent and the initiator to obtain a pre-dispersion;

carrying out second mixing treatment on the resin matrix, the silane coupling agent, the curing agent and the rest of the auxiliary agent to obtain a first mixture;

carrying out third mixing treatment and filtering treatment on the first mixture and the conductive agent to obtain a second mixture;

and performing fourth mixing treatment on the second mixture and the pre-dispersion to obtain the conductive paste.

In the first step, a part of the auxiliary agent and the initiator in the embodiment of the present application are subjected to a first mixing treatment to obtain a highly dispersed pre-dispersion, so as to perform a subsequent mixing treatment. The first mixing treatment includes stirring treatment at 10-20 deg.C and at 100-500 r/min for 5-10 min. And secondly, carrying out second mixing treatment on the resin matrix, the silane coupling agent, the curing agent and the residual auxiliary agent, wherein the silane coupling agent, the curing agent and the residual auxiliary agent are distributed in the resin matrix to obtain a highly dispersed first mixture. The second mixing treatment comprises stirring treatment at 10-30 deg.C and 500-1000 r/min for 5-10 min. And thirdly, performing third mixing treatment and filtering treatment on the first mixture and the conductive agent, wherein the conductive agent is distributed in the first mixture to obtain a highly dispersed second mixture. The third mixing treatment comprises stirring treatment, wherein the stirring temperature is 10-30 ℃, the stirring speed is 100-500 r/min, and the stirring is 10-30 min. And fourthly, carrying out fourth mixing treatment on the second mixture and the pre-dispersion, wherein the pre-dispersion is distributed in the second mixture to obtain the highly conductive slurry. The fourth mixing treatment comprises stirring treatment, wherein the stirring temperature is 20-30 ℃, the stirring speed is 100-500 r/min, and the stirring is 10-30 min.

The solar cell provided by the embodiment of the application comprises an HIT solar cell, and comprises a substrate and an electrode combined on the substrate, wherein the electrode is a conductive layer formed by curing the conductive paste prepared by the conductive paste or the preparation method of the conductive paste, the conductive paste is cured, under the conditions of an initiator and a curing agent, a resin matrix and a silane coupling agent in an organic carrier are cured to form a three-dimensional network structure, the conductive agent is dispersed in the conductive paste, and in the curing process, organic matters on the surface of the conductive agent are decomposed to form a conductive path, so that the conductivity of the solar cell is improved.

In order to clearly understand the details and operations of the above embodiments of the present application and to obviously show the advanced performance of the organic vehicle and the preparation method thereof, the conductive paste and the preparation method thereof, and the solar cell in the embodiments of the present application, the above technical solutions are illustrated by a plurality of examples.

EXAMPLE 1

The embodiment provides a conductive silver paste for high conductivity and low contact resistance HJT, which comprises the following components in percentage by mass:

hydrogenated bisphenol A epoxy resin 2.07 parts

Phenolic epoxy resin 1 part

1 part of hydrolytic dow coming 6040 silane coupling agent

0.43 part of No. 70 acid anhydride

Sulfonium salt cation thermal initiator 0.1 part

0.17 part of modified acrylic acid dispersant

0.05 part of TDO dispersant

0.05 part of n-butyl titanate

Diethylene glycol monobutyl ether 0.93 parts

Diethylene glycol butyl ether acetate 2 parts

60 parts of flake silver powder with particle size of 2.7 microns

10 parts of dendritic silver powder with particle size of 2 micrometers

22.1 parts of spherical silver powder with particle size of 0.4 micrometer

0.1 part of 97In3Ag alloy with grain diameter of 0.7 micron

Wherein the hydrolysis conditions of the Dow Corning 6040 coupling agent are as follows:

a. adding absolute ethyl alcohol: deionized water 9: 1,100 g, adding 0.02 g of acetic acid, and adjusting the pH value to 5.5;

b. adding 4g of silane coupling agent into 96g of solution a, heating to 50 ℃, and stirring for 2 hours;

c. and b, putting the completely hydrolyzed mixture into an oven at 100 ℃ for 10min, and removing the alcohol-water solution.

d. And (4) sieving the hydrolysate after water removal by using a silica gel sieve to further remove residual water. Obtaining the hydrolyzed silane coupling agent.

The coating method of the flaky silver powder with the particle size of 2.7 micrometers comprises the following steps: weighing 10g of low-temperature dissociable organic coating benzotriazole (C6H5N3) and adding into 100g of 3% acetic acid ethanol solution for standby, then adding 2.7 micron flaky silver powder into the low-temperature dissociable organic coating solution, soaking for 1min, filtering and washing.

EXAMPLE 2

aliphatic epoxy resin 1 part

0.5 part of hydrogenated bisphenol F epoxy resin

0.93 portion of hydrolytic KH560 silane coupling agent

1 part of phthalic anhydride

Sulfonium salt cation thermal initiator 0.02 part

Oleic acid 1.07 parts

0.03 portion of TDO dispersant

0.05 part of epoxy modified polyfunctional phosphate

122.14 parts of alcohol ester

0.86 part of tributyl citrate

20 portions of spheroidal silver powder with the grain diameter of 1.09 microns

11.4 parts of flake silver powder with particle size of 4.5 microns

60 portions of spherical silver powder with the grain diameter of 0.6 micron

1 part of Sn99.3Cu0.7 alloy with particle size of 2 microns

Wherein the hydrolysis conditions of the KH560 coupling agent are as follows:

a. adding absolute ethyl alcohol: deionized water 9: 1,100 g, adding 0.03 g of acetic acid, and adjusting the pH value to 4.5;

b. adding 4g of silane coupling agent into 96g of solution a, heating to 60 ℃, and stirring for 1.5 hours;

c. and b, putting the completely hydrolyzed mixture into a 110 ℃ oven for 8min, and removing the alcohol-water solution.

EXAMPLE 3

phenolic epoxy resin 3.2 parts

0.5 part of hydrolytic Daokangning 6040 silane coupling agent

Hexahydrophthalic anhydride 0.23 part

0.14 portion of boron-amine cation thermal initiator

Oleic acid 0.31 part

0.15 portion of TDO dispersant

0.08 portion of polyester modified phosphate

Diethylene glycol monobutyl ether 1.3 parts

67.4 parts of 42 percent silver-coated copper powder with the particle size of 3.9 microns

26.5 parts of spherical silver powder with particle size of 0.8 micrometer

1.5 parts of Sn99Ag0.3Cu0.7 alloy with particle size of 2 microns

a. mixing absolute ethyl alcohol: deionized water 9: 1,100 g, adding 0.03 g of acetic acid, and adjusting the pH value to 4.5;

b. adding 4g of silane coupling agent into 96g of solution a, heating to 70 ℃, and stirring for 1 hour;

c. and (4) putting the completely hydrolyzed b into an oven at 120 ℃ for 5min, and removing the alcohol-water solution.

The method for treating the silver-coated copper powder with the particle size of 3.9 microns comprises the following steps:

adding 100g of silver-coated copper powder into 500ml of ethanol, carrying out ultrasonic oscillation for 30min, washing, adding an ethanol solution of gamma-glycidoxypropyltrimethoxysilane, carrying out ultrasonic oscillation for 30min, filtering, and baking in an oven at 80 ℃ for 1 h.

The surface coating method comprises the following steps:

weighing 10g of low-temperature dissociable organic coating benzamidine (C7H6N2) and adding the weighed 10g of low-temperature dissociable organic coating benzamidine into 100g of 3% acetic acid ethanol solution for later use, then adding the treated silver-coated copper powder with the diameter of 3.9 microns into the low-temperature dissociable organic coating solution for soaking for 1min, and carrying out suction filtration and washing.

EXAMPLE 4

phenolic epoxy resin 3.2 parts

Dow Corning 6040 silane coupling agent 0.5 parts

Hexahydrophthalic anhydride 0.23 part

0.14 portion of boron-amine cation thermal initiator

Oleic acid 0.31 part

0.15 portion of TDO dispersant

0.08 portion of polyester modified phosphate

Diethylene glycol monobutyl ether 1.3 parts

26.5 parts of spherical silver powder with particle size of 0.8 micrometer

1.5 parts of Sn99Ag0.3Cu0.7 alloy with particle size of 2 microns

The surface coating method comprises the following steps:

weighing 10g of low-temperature dissociable organic coating benzimidazole (C7H6N2) and adding the weighed 10g of low-temperature dissociable organic coating benzimidazole into 100g of 3% acetic acid ethanol solution for later use, then adding the treated silver-coated copper powder with the diameter of 3.9 micrometers into the low-temperature dissociable organic coating solution, soaking for 1min, carrying out suction filtration and washing.

Example 5

This embodiment is a method for preparing the conductive silver paste for HJT with high conductivity and low contact resistance of example 1, which includes the following steps:

a. taking 1.07 parts of oleic acid, adding 0.02 part of sulfonium salt cation thermal initiator, controlling the temperature of a high-speed dispersion machine at 20 ℃, and stirring at the rotating speed of 300r/min for 5min to obtain a pre-dispersion.

b. Taking 1 part of aliphatic epoxy resin, 0.5 part of hydrogenated bisphenol F epoxy resin, 0.93 part of hydrolyzed KH560 silane coupling agent, 1 part of phthalic anhydride, 0.03 part of TDO dispersant, 0.05 part of epoxy modified polyfunctional group phosphate, 2.14 parts of alcohol ester 12 and 0.86 part of tributyl citrate, putting the mixture into a contact type vacuum planetary stirrer, controlling the rotating speed at 500r/min, controlling the temperature at 20 ℃, and stirring for 8 min.

c. Keeping the temperature at 20 ℃, adding 20 parts of spherical silver powder with the particle size of 1.09 microns, 11.4 parts of flaky silver powder with the particle size of 4.5 microns, 60 parts of spherical silver powder with the particle size of 0.6 microns and 1 part of Sn99.3Cu0.7 alloy with the particle size of 2 microns, stirring at the rotating speed of 100r/min for 30 min.

d. After being stirred uniformly by the contact type planetary stirrer, the mixture is transferred into a three-roll grinder to be rolled, the temperature is controlled at 20 ℃, the grinding fineness is 10 microns, the mixture is subjected to rotary blade coating and vacuum filtration, and the mesh number of a filter screen is 420 meshes.

e. And (b) adding 1.09 parts of the dispersant and initiator pre-dispersion in the step a into the filtered slurry, putting the filtered slurry into a contact type vacuum planetary stirrer, carrying out vacuum stirring, controlling the temperature to be 20 ℃, controlling the stirring speed to be 200r/min, stirring for 20min, discharging and canning to obtain the catalyst.

Example 6

This embodiment is a method for preparing the conductive silver paste for HJT with high conductivity and low contact resistance of the embodiment 2, which includes the following steps:

b. Taking 1 part of aliphatic epoxy resin, 0.5 part of hydrogenated bisphenol F epoxy resin, 0.93 part of hydrolyzed KH560 silane coupling agent, 1 part of phthalic anhydride, 0.03 part of TDO dispersant, 0.05 part of epoxy modified polyfunctional phosphate, 2.14 parts of alcohol ester 12 and 0.86 part of tributyl citrate, and stirring for 8min in a contact vacuum planetary stirrer at the rotating speed of 500r/min and the temperature of 20 ℃.

Example 7

This embodiment is a method for preparing the conductive silver paste for HJT with high conductivity and low contact resistance of embodiment 3, which includes the following steps:

a. taking 0.31 part of oleic acid, adding 0.14 part of sulfonium salt cation thermal initiator, controlling the temperature of a high-speed dispersion machine at 15 ℃, and stirring at the rotating speed of 100r/min for 10min to obtain a pre-dispersion.

b. 3.2 parts of novolac epoxy resin, 0.5 part of hydrolyzed dianthron 6040 silane coupling agent, 0.23 part of hexahydrophthalic anhydride, 0.15 part of TDO dispersant, 0.08 part of polyester modified phosphate and 1.3 parts of diethylene glycol butyl ether are put into a contact type vacuum planetary stirrer, the rotating speed is 1000r/min, the temperature is controlled at 10 ℃, and the stirring is carried out for 10 min.

c. Keeping the temperature at 10 ℃, adding 67.4 parts of 42% silver-coated copper powder with the particle size of 3.9 micrometers, 26.5 parts of spherical silver powder with the particle size of 0.8 micrometers and 1.5 parts of Sn99Ag0.3Cu0.7 alloy with the particle size of 2 micrometers, stirring at the rotating speed of 200r/min for 25 min.

d. After being stirred uniformly by the contact type planetary stirrer, the mixture is transferred into a three-roll grinder to be rolled, the temperature is controlled at 15 ℃, the grinding fineness is 5 microns, the mixture is subjected to rotary blade coating and vacuum filtration, and the mesh number of a filter screen is 420 meshes.

e. And (b) adding 0.45 part of the dispersant and initiator pre-dispersion in the step a into the filtered slurry, putting the filtered slurry into a contact type vacuum planetary stirrer, carrying out vacuum stirring, controlling the temperature to be 20 ℃, controlling the stirring speed to be 150r/min, stirring for 15min, discharging and canning to obtain the catalyst.

Example 8

This embodiment is a method for preparing the conductive silver paste for HJT with high conductivity and low contact resistance of example 4, which includes the following steps:

b. 3.2 parts of novolac epoxy resin, 0.5 part of Dow Corning 6040 silane coupling agent, 0.23 part of hexahydrophthalic anhydride, 0.15 part of TDO dispersant, 0.08 part of polyester modified phosphate and 1.3 parts of diethylene glycol butyl ether are put into a contact type vacuum planetary stirrer, the rotating speed is 1000r/min, the temperature is controlled at 10 ℃, and the stirring is carried out for 10 min.

Comparative example 1

The components and the mass percentage are as follows:

aliphatic epoxy resin 1 part

0.5 part of hydrogenated bisphenol F epoxy resin

0.93 portion of KH560 silane coupling agent

1 part of phthalic anhydride

Sulfonium salt cation thermal initiator 0.02 part

Oleic acid 1.07 parts

0.03 portion of TDO dispersant

0.05 part of epoxy modified polyfunctional phosphate

122.14 parts of alcohol ester

0.86 part of tributyl citrate

20 portions of spheroidal silver powder with the grain diameter of 1.09 microns

11.4 parts of flake silver powder with particle size of 4.5 microns

60 parts of spherical silver powder with particle size of 0.6 micrometer

1 part of Sn99.3Cu0.7 alloy with particle size of 2 microns

Comparative example 2

The embodiment is a method for preparing the conductive silver paste of embodiment 1, which includes the following steps:

a. taking 0.17 part of modified acrylic acid dispersant, adding 0.1 part of sulfonium salt cation thermal initiator, controlling the temperature of a high-speed dispersion machine to be 10 ℃, and stirring at the rotating speed of 100r/min for 10min to obtain a pre-dispersion.

b. Taking 2.07 parts of hydrogenated bisphenol A epoxy resin, 1 part of novolac epoxy resin, 1 part of Dow Corning 6040 silane coupling agent, 0.43 part of No. 70 anhydride, 0.05 part of TDO dispersant, 0.05 part of n-butyl titanate, 0.93 part of diethylene glycol butyl ether and 2 parts of diethylene glycol butyl ether acetate, putting the mixture into a contact type vacuum planetary stirrer, controlling the rotating speed at 500r/min, controlling the temperature at 20 ℃, and stirring for 8 min.

c. Keeping the temperature at 20 ℃, adding 60 parts of flake silver powder with the particle size of 2.7 microns, 10 parts of dendritic silver powder with the particle size of 2 microns, 22.1 parts of spherical silver powder with the particle size of 0.4 microns and 0.1 part of 97In3Ag alloy with the particle size of 0.7 microns, stirring at the rotating speed of 100r/min for 30 min.

e. And (b) adding 0.27 part of the mixture of the dispersing agent and the initiator in the step a into the filtered slurry, putting the filtered slurry into a contact type vacuum planetary stirrer, carrying out vacuum stirring, controlling the temperature to be 20 ℃, stirring at the rotating speed of 200r/min for 20min, discharging and canning to obtain the catalyst.

In the above-mentioned preparation methods of examples 5 to 8 and comparative example 2, the stirring speed is controlled such that after the silver powder is added, the viscosity is relatively high, and too high stirring speed may cause the heating of the stirrer motor to cause a failure on the one hand, and on the other hand, too high stirring may cause the temperature of the silver paste to rise, and the system may undergo a curing reaction, and similarly, the temperature is controlled below 30 ℃ to reduce the reactivity of the system during the preparation of the paste. The preparation flow is shown in FIG. 8.

Performance testing

The conductive silver paste for HJT in example 1, example 2, example 3, example 4, and comparative example 1 was tested for the following properties:

(1) resistivity of

Designing a screen pattern with the width of 1cm and the length of 10cm, and curing after printing by a printer, wherein three screen patterns form a group. The wire resistance is tested through the resistance tester, the height is tested through the 3D microscope, and the calculation can be obtained, wherein the calculation formula is as follows:

ρ＝R*d*w/L

where ρ is the resistivity, the unit Ω. m, R is the resistance of the pattern line, the unit Ω, d is the thickness of the pattern, the unit m, w is the width of the pattern, the unit m, L is the length of the pattern, and the unit m. Please refer to fig. 5.

(2) Contact resistance

The screen pattern is designed as shown in fig. 6 and 7.

Adhesion test

The examples and comparative examples were each printed with a rectangular block of 1.5CM by 1CM, tested according to the test standard GB 9286.

(4) Stability of

The initial viscosity was compared with the viscosity after 24 hours at room temperature, measured as a rotational viscometer, and the viscosity at 25 ℃ was measured at 14# spindle, 10 rpm.

(5) Curing conditions

The test method according to (1), (2) and (3), wherein the curing conditions are as follows: drying at 150 deg.C for 10min, and curing at 190 deg.C for 20 min.

The test results were as follows:

in which example 1 is distinguished from comparative example 1 in that example 1 uses a hydrolyzed coupling agent, whereas comparative example 1 uses an unhydrolyzed coupling agent, the hydrolyzed coupling agent can provide superior electrical conductivity and higher adhesion strength in view of electrical properties and adhesion. The electrical properties of the copper-clad metal powder were slightly higher than that of comparative example 1, but all were 5 x 10 ^-8 Within Ω. m, example 3 differs from example 4 in that example 4 has slightly inferior electrical properties to example 3 without using a decoupling agent, and adhesion is comparable to comparative example 1 and slightly inferior to example 3. It can be seen that the electrical properties and adhesion of all silver powders are optimized by the action of the hydrolytic coupling agent, and the electrical properties and adhesion of all the examples using the hydrolytic coupling agent are improved。

The above description is only a preferred embodiment of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The organic carrier is characterized by comprising the following raw materials in parts by weight:

wherein the silane coupling agent contains an epoxy group.

2. The organic vehicle of claim 1, wherein the material forming the resin matrix comprises an epoxy resin or a modified epoxy resin;

or/and the silane coupling agent comprises Y _n SiX ₃ Said Y is _n SiX ₃ Y in (2) contains the epoxy group, and X contains an alkoxy group;

or/and the curing agent comprises at least one of methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 70-acid anhydride, phthalic anhydride, hexahydrophthalic anhydride and diphenyl ether tetracarboxylic dianhydride;

or/and the initiator comprises at least one of a blocked phosphate cation initiator, a blocked sulfonium salt cation initiator and a boron-amine cation initiator;

or/and the auxiliary agent comprises at least one of an adhesion promoter, a non-reactive diluent and an agent containing an acid group.

3. The organic vehicle of claim 2, wherein the alkoxy group comprises-OCH ₃ 、-OC ₂ H ₅ 、-OCOCH ₃ 、-OCH ₂ CH ₂ OCH ₃ At least one of;

or/and the epoxy resin comprises at least one of hydrogenated epoxy resin, novolac epoxy resin, alicyclic epoxy resin and aliphatic epoxy resin;

or/and the modified epoxy resin comprises at least one of polyurethane modified epoxy resin, acrylic resin modified epoxy resin and polyester modified epoxy resin.

4. The organic vehicle of claim 2, wherein the adhesion promoter comprises at least one of a modified phosphate ester compound, a phthalate ester compound, a polyester modified phosphate ester, an epoxy modified multifunctional phosphate ester, n-butyl titanate, and a titanium acetylacetonate chelate;

the non-reactive diluent comprises at least one of alcohol ester 12, diethylene glycol butyl ether acetate, tributyl citrate, terpineol and DBE;

the reagent containing acidic groups comprises at least one of oleic acid, TDO, acrylic dispersant and modified polyester dispersant.

5. A method for preparing an organic vehicle, which comprises mixing the resin matrix according to any one of claims 1 to 4, a silane coupling agent, a curing agent, an initiator and an auxiliary agent to obtain the organic vehicle.

6. The method for producing an organic vehicle according to claim 5, further comprising a step of subjecting the silane coupling agent to hydrolysis treatment to obtain a hydrolyzed silane coupling agent, before the mixing treatment step;

and/or further comprising the step of performing pre-dispersion treatment on the auxiliary agent and the initiator to obtain a pre-dispersion body.

7. The method for producing an organic vehicle according to claim 6, wherein the hydrolysis treatment specifically comprises the steps of:

and mixing the silane coupling agent and the solvent, adjusting the pH value to 4.5-5.5, and heating to 50-70 ℃.

8. An electroconductive paste comprising a mixture of the organic vehicle according to any one of claims 1 to 4 and an electroconductive agent.

9. The conductive paste according to claim 8, wherein the weight ratio of the organic vehicle to the conductive agent is 88-94: 18-6;

or/and the shape of the conductive agent comprises at least one of spherical shape, spherical-like shape, sheet-like shape, fiber and dendritic shape;

and/or when the shape of the conductive agent is at least one of spherical, spherical-like, flaky-like and dendritic, the average particle size of the conductive agent is 0.2-10 micrometers.

10. The preparation method of the conductive paste is characterized by comprising the following steps of:

mixing the organic vehicle according to any one of claims 1 to 4 with a conductive agent to obtain a mixture.

11. The method for preparing conductive paste according to claim 10, wherein a part of the auxiliary agent and the initiator are subjected to a first mixing process to obtain a pre-dispersion;

12. The method for preparing the conductive paste according to claim 11, wherein the first mixing treatment comprises stirring treatment, and the stirring temperature is 10-20 ℃, the rotation speed is 100-500 r/min, and the time is 5-10 min;

or/and the second mixing treatment comprises stirring treatment, wherein the stirring temperature is 10-30 ℃, the rotating speed is 500-1000 r/min, and the time is 5-10 min;

or/and the third mixing treatment comprises stirring treatment, wherein the stirring temperature is 10-30 ℃, the stirring speed is 100-500 r/min, and the stirring is 10-30 min;

or/and the temperature in the filtering treatment is 15-25 ℃, and the filtering mesh number is 360-420 meshes;

and/or the fourth mixing treatment comprises stirring treatment, wherein the stirring temperature is 20-30 ℃, the stirring speed is 100-500 r/min, and the stirring is 10-30 min.

13. A solar cell comprising a substrate and an electrode bonded to the substrate, wherein the electrode is formed by curing a conductive paste prepared by a method comprising preparing the conductive paste according to claim 8 or 9 or the conductive paste according to any one of claims 10 to 12.