CN114203336A - Graphene-containing general silver paste for main fine grid of HJT solar cell and preparation method thereof - Google Patents

Abstract

The invention provides a graphene-containing general silver paste for main fine grids of an HJT solar cell, which is prepared from the following components in percentage by mass: 15-19% of micron-sized flake silver powder, 68-72% of submicron-sized spherical silver powder, 3-7% of nano-sized spherical silver powder, 0.12-0.16% of filler, 2-4% of resin, 0.1-0.2% of modifier, 3-5% of solvent, 0.1-0.2% of coupling agent, 0.1-0.2% of dispersant, 0.1-0.2% of curing agent, 0.1-0.2% of accelerator and 0.08-0.16% of wetting agent. The invention not only can realize one-step printing of the main grid and the fine grid, but also can reduce the overall resistivity and improve the adhesive force, so that the dispersibility, the thixotropy and the weather resistance of the slurry are better.

Description

Graphene-containing general silver paste for main fine grid of HJT solar cell and preparation method thereof

Technical Field

The invention relates to the technical field of solar cell metallization, in particular to graphene-containing general silver paste for a main fine grid of an HJT solar cell and a preparation method thereof.

Background

With the continuous progress of photovoltaic cell technology, the trend of P-type to N-type iteration is started in 2021, which is a step toward higher efficiency, and N-type technology routes represented by topocon (tunnel Oxide passivation contacts) tunneling Oxide passivation contact cells and hjt (heterojunction with Intrinsic thin) heterojunction cells are broken through successively, and the industrialization process is expected to be accelerated. Compared with TOPCon, HJT has the advantages of better contact resistance and passivation effect, higher photoelectric conversion efficiency, capability of meeting the requirements of the next-generation laminated cell and the like, and is more suitable for flaking. At present, the electrode of the HJT battery mainly adopts a screen printing process and uses low-temperature curing conductive silver paste, wherein the low-temperature silver paste for fine grid printing needs to have lower bulk resistance and contact resistance, high adhesive force, high aspect ratio, excellent weather resistance and excellent printability; and the low-temperature silver paste for main grid printing needs good conductivity, printability and excellent tensile force.

The defects and shortcomings of the prior art are as follows:

1. the main fine grid is printed step by step, so that the production efficiency is reduced; two kinds of main and fine grid paste are adopted for printing, the problem of mutual matching exists, and the reason for locking the production line is inconvenient due to abnormity;

2. the main grid requires excellent tensile force, and the proportion of resin needs to be properly increased, so that the resistivity is increased;

3. the size and specific surface area of the nano-ball powder used by the fine grid are inappropriate as well as the coupling agent and the dispersing agent, so that the contact resistance and the adhesive force are poor, the dispersion is uneven, the viscosity of the slurry is high, and the curing reaction activity of the resin is reduced;

4. in order to ensure the printing height-width ratio, the used thixotropic agent can not volatilize when being cured at low temperature and remains in the electrode as impurities, so that the resistivity is improved;

5, the epoxy resin and the curing agent are not suitable, so that water mist and salt mist corrode the contact position of the grid line and the surface of the silicon wafer along with the prolonging of time, the contact resistance is obviously increased, the adhesive force is reduced, and the weather resistance of the grid line is poor.

Disclosure of Invention

In order to solve the problems, the invention discloses a graphene-containing general silver paste for main fine grids of an HJT solar cell and a preparation method thereof, which can realize one-step printing of the main and fine grids, reduce the overall resistivity, improve the adhesive force and ensure that the dispersibility, the thixotropy and the weather resistance of the paste are better.

The specific scheme is as follows:

the utility model provides a general silver thick liquid of HJT solar cell owner thin bars that contains graphite alkene which characterized in that: the paint is prepared from the following components in percentage by mass: 15-19% of micron-sized flake silver powder, 68-72% of submicron-sized spherical silver powder, 3-7% of nano-sized spherical silver powder, 0.12-0.16% of filler, 2-4% of resin, 0.1-0.2% of modifier, 3-5% of solvent, 0.1-0.2% of coupling agent, 0.1-0.2% of dispersant, 0.1-0.2% of curing agent, 0.1-0.2% of accelerator and 0.08-0.16% of wetting agent.

As a further improvement of the invention, the micron-sized plate-like silver powder is D50: 1-5um, wherein the submicron spherical silver powder is D50: 0.2-0.5um, wherein the nano-scale spherical silver powder is D50: 10-50 nm.

As a further improvement of the invention, the filler is one or two of hydroxylated graphene and carboxylated graphene, wherein the sheet diameter of the carboxylated graphene is 0.5-5um, and the thickness of the carboxylated graphene is 0.8-1.2 nm.

As a further improvement of the invention, the resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, carboxyl-terminated polyester resin and carboxyl acrylic resin.

As a further improvement of the invention, the modifier is one or more of acrylic acid, gallic acid, dehydroabietic acid methyl ester, dehydroabietic acid, oleic acid and 3,3',5,5' -tetramethyl diphenol.

As a further improvement of the invention, the solvent is one or more of butyl carbitol, butyl carbitol acetate, terpineol, alcohol ester dodeca, tributyl citrate and diethylene glycol butyl ether.

As a further improvement of the invention, the coupling agent is one or more of silane coupling agents A151, A171 and A172.

As a further improvement of the invention, the dispersant is one or more of octyl phenyl polyoxyethylene ether, N-methyl pyrrolidone and polyethylene glycol oleate.

As a further improvement of the invention, the curing agent is one or more of triglycidyl isocyanurate, beta-hydroxyalkyl amide, acrylic acid modified hydroxyalkyl amide and oleic acid modified hydroxyalkyl amide.

As a further improvement of the invention, the accelerator is one or more of carboxylic ester, methyl hydrazine and amino imine.

As a further improvement of the invention, the wetting agent is one or more of 2.4.7.9-tetramethyl-5-decyne-4.7-diol, oleamidopropyl dimethylamine, trimethylbutenediol, oleyl alcohol polyoxyethylene ether and a fluorine surfactant FC-4430.

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene is characterized by comprising the following steps: the method comprises the following specific steps:

slowly pouring the nano-scale spherical silver powder into a solvent along the wall of a beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, stirring for 1 hour, then mixing by using a centrifugal machine, setting the rotating speed to be 1200rpm, setting the temperature to be 25 ℃, and mixing for 30 minutes uniformly to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

adding micron-grade flaky silver powder and submicron spherical silver powder into the third mixture, mixing by using a three-roller machine, setting the rotation speed to be 750rpm, and mixing for 3 times at the first step, wherein the initial roller gap is 60 microns and the final roller gap is 30 microns; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing the primary roller gap 10um and the final roller gap 4um for 6 times to ensure that the dispersion is uniform, thereby obtaining the finished silver paste.

The invention has the beneficial effects that:

1. compared with common graphene, hydroxylated or carboxylated graphene has higher affinity for polar molecules and is easier to disperse in a carrier taking epoxy resin as a main body;

2. by taking graphene as a core, compounding the point-like spherical nano silver powder and the flake silver powder, adding a proper dispersing agent, adopting a proper dispersing method, and utilizing the excellent electrical conductivity, thermal conductivity and flexible sheet structure of the graphene, efficient point, line and surface contact can be formed on the whole epoxy resin system to form a three-dimensional conductive network, so that the volume resistance can be reduced, and meanwhile, a larger pulling force is provided;

3. the graphene has a large diameter-thickness ratio, and the thixotropy of the silver paste can be improved by adding a small amount of graphene, so that a better height-width ratio and conversion efficiency are obtained;

4. from the thermal property, the graphene is the known material with the highest thermal conductivity, the graphene is added as a filler to improve the heat resistance of the epoxy resin, the epoxy resin is more compact in crosslinking after being cured, the graphene is more compact in shrinkage, and the thermal shock resistance is better;

5. due to the small-size effect and the two-dimensional lamellar structure of the graphene, the defects in the epoxy resin coating can be improved, so that a compact isolation layer can be formed in the coating, the water-resisting effect is improved, the self-corrosion current density is reduced, and the acid resistance, salt resistance and other corrosion resistance and weather resistance are improved;

6. selecting a proper dispersing agent, namely octyl phenyl polyoxyethylene ether, N-methyl pyrrolidone and polyethylene glycol oleate to improve the dispersion uniformity;

7. selecting proper silane coupling agents A151, A171 and A172 to improve the bonding property and compatibility between graphene and epoxy resin;

8. the dispersion is better by using bubbling and stirring together.

Detailed Description

The present invention will be further illustrated below with reference to specific embodiments, which are to be understood as merely illustrative and not limitative of the scope of the present invention.

Example 1

The graphene-containing general silver paste for the main fine grid of the HJT solar cell is prepared from the following components in percentage by mass:

micron-sized plate-like silver powder (D50: 1 um): 15 percent of

Submicron spherical silver powder (D50: 0.2 um): 72 percent

Nanoscale spherical silver powder (D50: 10 nm): 5 percent of

Filling: hydroxylated graphene (sheet diameter of 0.5-5um, thickness of 0.8-1.2 nm): 0.14 percent

Resin: 2 percent of bisphenol A epoxy resin

Modifying agent: acrylic acid: 0.1 percent of

Solvent: butyl carbitol: 5 percent of

Coupling agent: silane coupling agent a 151: 0.1 percent of

Dispersing agent: octyl phenyl polyoxyethylene ether: 0.1 percent of

Curing agent: triglycidyl isocyanurate: 0.2 percent of

Accelerator (b): carboxylic acid ester: 0.2 percent of

Wetting agent: 2.4.7.9-tetramethyl-5-decyne-4.7-diol: 0.16 percent

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene comprises the following specific steps:

and (2) slowly pouring the nano-scale spherical silver powder into the solvent along the wall of the beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, and stirring for 1 hour. Then using a centrifuge to mix, rotating at 1200rpm, temperature 25 ℃, time 30 min. Uniformly mixing to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

and (4) finally, adding the micron-scale flaky silver powder and the submicron-scale spherical silver powder into the third mixture, mixing by using a three-roll machine, and setting the rotating speed to be 750 rpm. Firstly, mixing for 3 times, wherein the primary roller gap is 60um and the final roller gap is 30 um; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing for 6 times by using an initial roller gap of 10um and a final roller gap of 4 um. So that the silver paste is dispersed uniformly to obtain the finished product of silver paste.

Example 2

The graphene-containing general silver paste for the main fine grid of the HJT solar cell is prepared from the following components in percentage by mass:

micron-sized plate-like silver powder (D50: 5 um): 16 percent of

Submicron spherical silver powder (D50: 0.5 um): 69 percent

Nanoscale spherical silver powder (D50: 50 nm): 7 percent of

Filling: carboxylated graphene (sheet diameter of 0.5-5um, thickness of 0.8-1.2 nm): 0.16 percent

Resin: bisphenol F epoxy resin: 2.5 percent

Modifying agent: and (3) gallic acid: 0.12 percent of

Solvent: butyl carbitol acetate: 4.5 percent

Coupling agent: silane coupling agent a 171: 0.12 percent of

Dispersing agent: n-methylpyrrolidone: 0.12 percent of

Curing agent: β -hydroxyalkylamides: 0.17 percent

Accelerator (b): methyl hydrazine: 0.17 percent

Wetting agent: oleamidopropyl dimethylamine: 0.14 percent

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene comprises the following specific steps:

and (2) slowly pouring the nano-scale spherical silver powder into the solvent along the wall of the beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, and stirring for 1 hour. Then using a centrifuge to mix, rotating at 1200rpm, temperature 25 ℃, time 30 min. Uniformly mixing to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

and (4) finally, adding the micron-scale flaky silver powder and the submicron-scale spherical silver powder into the third mixture, mixing by using a three-roll machine, and setting the rotating speed to be 750 rpm. Firstly, mixing for 3 times, wherein the primary roller gap is 60um and the final roller gap is 30 um; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing for 6 times by using an initial roller gap of 10um and a final roller gap of 4 um. So that the silver paste is dispersed uniformly to obtain the finished product of silver paste.

Example 3

The graphene-containing general silver paste for the main fine grid of the HJT solar cell is prepared from the following components in percentage by mass:

micron-sized plate-like silver powder (D50: 3 um): 17 percent of

Submicron spherical silver powder (D50: 0.3 um): 71 percent of

Nanoscale spherical silver powder (D50: 30 nm): 4 percent of

Filling: one or two of carboxylated graphene (sheet diameter of 0.5-5um, thickness of 0.8-1.2 nm): 0.13 percent

Resin: carboxyl-terminated polyester resin: 3 percent of

Modifying agent: dehydroabietic acid methyl ester: 0.15 percent

Solvent: terpineol: 4 percent of

Coupling agent: one or more of silane coupling agents A172: 0.15 percent

Dispersing agent: polyethylene glycol oleate: 0.15 percent

Curing agent: acrylic acid modified hydroxyalkyl amide: 0.15 percent

Accelerator (b): aminoimine: 0.15 percent

Wetting agent: trimethylbutylene glycol: 0.12 percent of

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene comprises the following specific steps:

and (2) slowly pouring the nano-scale spherical silver powder into the solvent along the wall of the beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, and stirring for 1 hour. Then using a centrifuge to mix, rotating at 1200rpm, temperature 25 ℃, time 30 min. Uniformly mixing to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

and (4) finally, adding the micron-scale flaky silver powder and the submicron-scale spherical silver powder into the third mixture, mixing by using a three-roll machine, and setting the rotating speed to be 750 rpm. Firstly, mixing for 3 times, wherein the primary roller gap is 60um and the final roller gap is 30 um; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing for 6 times by using an initial roller gap of 10um and a final roller gap of 4 um. So that the silver paste is dispersed uniformly to obtain the finished product of silver paste.

Example 4

The graphene-containing general silver paste for the main fine grid of the HJT solar cell is prepared from the following components in percentage by mass:

micron-sized plate-like silver powder (D50: 2 um): 18 percent of

Submicron spherical silver powder (D50: 0.3 um): 68 percent of

Nanoscale spherical silver powder (D50: 20 nm): 6 percent of

Filling: hydroxylated graphene (sheet diameter of 0.5-5um, thickness of 0.8-1.2 nm): 0.15 percent

Resin: 3.5 percent of carboxyl acrylic resin

Modifying agent: dehydroabietic acid: 0.17 percent

Solvent: alcohol ester twelve: 3.5 percent

Coupling agent: silane coupling agent a 151: 0.08%, a 171: 0.09 percent

Dispersing agent: octyl phenyl polyoxyethylene ether 0.08%, N-methyl pyrrolidone 0.09%

Curing agent: oleic acid-modified hydroxyalkyl amides: 0.12 percent of

Accelerator (b): carboxylate 0.06%, methyl hydrazine 0.06%

Wetting agent: oleyl alcohol polyoxyethylene ether 0.1%

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene comprises the following specific steps:

and (2) slowly pouring the nano-scale spherical silver powder into the solvent along the wall of the beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, and stirring for 1 hour. Then using a centrifuge to mix, rotating at 1200rpm, temperature 25 ℃, time 30 min. Uniformly mixing to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

and (4) finally, adding the micron-scale flaky silver powder and the submicron-scale spherical silver powder into the third mixture, mixing by using a three-roll machine, and setting the rotating speed to be 750 rpm. Firstly, mixing for 3 times, wherein the primary roller gap is 60um and the final roller gap is 30 um; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing for 6 times by using an initial roller gap of 10um and a final roller gap of 4 um. So that the silver paste is dispersed uniformly to obtain the finished product of silver paste.

Example 5

The graphene-containing general silver paste for the main fine grid of the HJT solar cell is prepared from the following components in percentage by mass:

micron-sized plate-like silver powder (D50: 4 um): 19 percent of

Submicron spherical silver powder (D50: 0.4 um): 70 percent of

Nanoscale spherical silver powder (D50: 40 nm): 3 percent of

Filling: 0.06% of hydroxylated graphene, 0.5-5um of carboxylated graphene (sheet diameter, 0.8-1.2nm of thickness): 0.06 percent

Resin: 2 percent of bisphenol F epoxy resin and 2 percent of carboxyl acrylic resin

Modifying agent: oleic acid 0.2%

Solvent: 3 percent of tributyl citrate

Coupling agent: silane coupling agent a 171: 0.1%, A172: 0.1 percent of

Dispersing agent: 0.1 percent of N-methyl pyrrolidone and 0.1 percent of polyethylene glycol oleate

Curing agent: beta-hydroxyalkylamide 0.05%, acrylic acid-modified hydroxyalkylamide 0.05%

Accelerator (b): 0.05 percent of methyl hydrazine and 0.05 percent of amino imine

Wetting agent: fluorine surfactant FC-4430: 0.08 percent

A preparation method of general silver paste for a main fine grid of an HJT solar cell containing graphene comprises the following specific steps:

and (2) slowly pouring the nano-scale spherical silver powder into the solvent along the wall of the beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, and stirring for 1 hour. Then using a centrifuge to mix, rotating at 1200rpm, temperature 25 ℃, time 30 min. Uniformly mixing to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

and (4) finally, adding the micron-scale flaky silver powder and the submicron-scale spherical silver powder into the third mixture, mixing by using a three-roll machine, and setting the rotating speed to be 750 rpm. Firstly, mixing for 3 times, wherein the primary roller gap is 60um and the final roller gap is 30 um; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing for 6 times by using an initial roller gap of 10um and a final roller gap of 4 um. So that the silver paste is dispersed uniformly to obtain the finished product of silver paste.

Comparison results

1. Tensile and weather resistance are compared, see table below:

as shown in the above table, the tensile force of the examples is larger than that of the comparative example, and the change of the contact resistance in the weather resistance test is smaller than that of the comparative example.

2. Comparison of slurry viscosity

The viscosity of the examples shown in the table is lower than that of the comparative examples, and the thixotropic value and the aspect ratio are higher, so that the printing property is better.

3. Comparison of cell Performance

The performance of the prepared HJT solar cell containing graphene of the above example is shown in the following table:

through the above table, the graphene-containing general silver paste for the main fine grid of the HJT solar cell in the embodiment has excellent performances such as conductivity, printability and conversion efficiency, and can meet the requirements of the screen printing grid of the mainstream HJT solar cell in the market.

The above embodiment contains general silver paste for the main fine grid of the HJT solar cell containing graphene, submicron and nanoscale spherical silver powder and graphene, and can form smaller resistivity, higher conversion efficiency and tensile force and more excellent weather resistance.

The invention adopts functionalized graphene, namely hydroxylated or carboxylated graphene, to increase the compatibility of the graphene in epoxy resin; selecting a proper dispersing agent, namely octyl phenyl polyoxyethylene ether, N-methyl pyrrolidone and polyethylene glycol oleate to improve the dispersion uniformity; selecting proper silane coupling agents A151, A171 and A172 to improve the bonding property and compatibility between graphene and epoxy resin; the dispersion is better by using bubbling and stirring together.

The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and such improvements and modifications are also considered to be within the scope of the present invention.

Claims (10)

1. The utility model provides a general silver thick liquid of HJT solar cell owner thin bars that contains graphite alkene which characterized in that: the paint is prepared from the following components in percentage by mass: 15-19% of micron-sized flake silver powder, 68-72% of submicron-sized spherical silver powder, 3-7% of nano-sized spherical silver powder, 0.12-0.16% of filler, 2-4% of resin, 0.1-0.2% of modifier, 3-5% of solvent, 0.1-0.2% of coupling agent, 0.1-0.2% of dispersant, 0.1-0.2% of curing agent, 0.1-0.2% of accelerator and 0.08-0.16% of wetting agent.

2. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the micron-sized flaky silver powder is D50: 1-5um, wherein the submicron spherical silver powder is D50: 0.2-0.5um, wherein the nano-scale spherical silver powder is D50: 10-50 nm.

3. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the filler is one or two of hydroxylated graphene and carboxylated graphene, wherein the sheet diameter of the carboxylated graphene is 0.5-5um, and the thickness of the carboxylated graphene is 0.8-1.2 nm.

4. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, carboxyl-terminated polyester resin and carboxyl acrylic resin; the modifier is one or more of acrylic acid, gallic acid, dehydroabietic acid methyl ester, dehydroabietic acid, oleic acid and 3,3',5,5' -tetramethyl diphenol; the solvent is one or more of butyl carbitol, butyl carbitol acetate, terpineol, alcohol ester dodeca, tributyl citrate and diethylene glycol butyl ether.

5. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the coupling agent is one or more of silane coupling agents A151, A171 and A172.

6. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the dispersing agent is one or more of octyl phenyl polyoxyethylene ether, N-methyl pyrrolidone and polyethylene glycol oleate.

7. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the curing agent is one or more of triglycidyl isocyanurate, beta-hydroxyalkylamide, acrylic acid modified hydroxyalkylamide and oleic acid modified hydroxyalkylamide.

8. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the accelerant is one or more of carboxylic ester, methylhydrazine and aminoimine.

9. The general silver paste containing graphene for main fine grids of HJT solar cells of claim 1, wherein: the wetting agent is one or more of 2.4.7.9-tetramethyl-5-decyne-4.7-diol, oleamidopropyl dimethylamine, trimethyl butylene glycol, oleyl alcohol polyoxyethylene ether and a fluorine surfactant FC-4430.

10. The method for preparing HJT solar cell main fine grid general silver paste containing graphene according to any one of claims 1 to 9, wherein the method comprises the following steps: the method comprises the following specific steps:

slowly pouring the nano-scale spherical silver powder into a solvent along the wall of a beaker by adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 25 ℃, stirring for 1 hour, then mixing by using a centrifugal machine, setting the rotating speed to be 1200rpm, setting the temperature to be 25 ℃, and mixing for 30 minutes uniformly to obtain a first mixture;

step (2) adopting a constant-temperature stirrer, setting the rotating speed to be 600rpm, setting the temperature to be 60 ℃, adding resin, introducing N2 gas at the bottom of a beaker, sequentially adding a wetting agent, a dispersing agent and a coupling agent into the beaker, slowly adding a filler after uniformly stirring, stirring for 1 hour, and then cooling to normal temperature to obtain a second mixture;

step (3) adding the second mixture, the modifier, the curing agent and the accelerator into the first mixture slowly in sequence by adopting a constant-temperature stirrer at normal temperature, setting the rotating speed to be 600rpm, stirring for 1 hour, then using a centrifugal machine to rotate the rotating speed to be 1200rpm, keeping the temperature to be 25 ℃, keeping the time to be 30min, and uniformly mixing to obtain a third mixture;

adding micron-grade flaky silver powder and submicron spherical silver powder into the third mixture, mixing by using a three-roller machine, setting the rotation speed to be 750rpm, and mixing for 3 times at the first step, wherein the initial roller gap is 60 microns and the final roller gap is 30 microns; secondly, mixing the primary roller gap of 30um and the final roller gap of 15um for 3 times; thirdly, mixing the primary roller gap 15um and the final roller gap 7um for 5 times; and step four, mixing the primary roller gap 10um and the final roller gap 4um for 6 times to ensure that the dispersion is uniform, thereby obtaining the finished silver paste.