CN118280629B - Conductive paste for TOPCon battery and production process thereof - Google Patents

Abstract

The invention discloses a conductive paste for a TOPCon battery and a production process thereof. The following raw materials are weighed in parts by weight: 3-5 parts of a conductive additive, 85-90 parts of silver powder, 1-5 parts of glass powder and 9-10 parts of a modified carrier. The raw materials are evenly mixed and ground to a fineness of 5 μm to obtain a conductive paste for a TOPCon battery. The conductive additive contains copper, titanium, silicon dioxide and a graphene structure, which can reduce the loss of electrons in a transmission process. Copper can also form a low-resistance ohmic contact with silicon or polycrystalline silicon, and is easy to form a large number of shallow silver-copper spikes. The silver-copper spikes become a bridge for current transmission, achieving better ohmic contact, and can prevent the silver metal spikes from penetrating a silicon substrate when formed, and improve the capture of light, so that light that could not be used originally is used, thereby broadening the absorption range of sunlight and improving the photoelectric conversion rate.

Description

A conductive paste for TOPCon battery and its production process

Technical Field

The invention relates to the technical field of TOPCon battery preparation, and in particular to a conductive slurry for a TOPCon battery and a production process thereof.

Background Art

Solar cells, also known as photovoltaic cells, are semiconductor devices that convert sunlight directly into electrical energy. TOPCon is a tunneling oxide passivation contact solar cell technology based on the principle of selective carriers. Its cell structure is an n-type silicon substrate cell. An ultra-thin layer of silicon oxide is prepared on the back of the cell, and then a thin layer of doped silicon is deposited. The two together form a passivation contact structure, which effectively reduces surface recombination and metal contact recombination. Silver aluminum paste is the conductive material for the front electrode of n-type TOPCon solar cells. It is mainly composed of a conductive functional phase, an inorganic bonding phase, and an organic carrier. The existing conductive paste is prone to form excessively long silver spikes during the sintering process, resulting in penetration of the silicon substrate, resulting in low cell conversion rate.

Summary of the invention

The purpose of the present invention is to provide a conductive paste for TOPCon batteries and a production process thereof, which solves the problems of large contact resistance and low conversion efficiency of the conductive paste at the current stage.

The purpose of the present invention can be achieved through the following technical solutions:

A production process of conductive paste for TOPCon batteries, specifically comprising the following steps:

The modified filler is placed in a tubular furnace, heated to 800-850°C at a heating rate of 5°C/min in a nitrogen atmosphere, and sintered for 2-3 hours to obtain a conductive additive. The following raw materials are weighed in parts by weight: 3-5 parts of conductive additive, 85-90 parts of silver powder, 1-5 parts of glass powder and 9-10 parts of modified carrier. The raw materials are mixed evenly and ground to a fineness of 5μm to obtain a conductive slurry for TOPCon batteries.

Further, the modified filler is prepared by the following steps:

Step A1: 2,2':6',2''-terpyridine-4'-carboxylic acid, anhydrous ethanol, p-toluenesulfonic acid and toluene are uniformly mixed, and the mixture is reacted for 10-15 hours at a speed of 120-150 r/min and a temperature of 90-100° C. to obtain an intermediate 1, and cupric chloride dihydrate is dissolved in anhydrous ethanol, and the intermediate 1 is added, and nitrogen is introduced for protection, and the mixture is refluxed for 3-5 hours at a speed of 60-80 r/min and a temperature of 78-80° C. to obtain a copper organic framework;

Step A2: Dispersing the copper organic framework in ethanol, adding sodium hydroxide solution, and reflux reacting for 10-15 hours at a temperature of 90-95° C. to obtain a functionalized organic framework, and uniformly mixing the functionalized organic framework, γ-aminopropylmethyldiethoxysilane, dicyclohexylcarbodiimide and toluene, and reacting for 2-3 hours at a speed of 150-200 r/min and a temperature of 40-50° C. to obtain a modified organic framework;

Step A3: Disperse graphene oxide in anhydrous ethanol, add KH550 and dicyclohexylcarbodiimide, react for 2-3 hours at a speed of 150-200 r/min and a temperature of 40-50°C to obtain pretreated graphene, mix the pretreated graphene, modified organic framework, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water and hydrochloric acid solution at a speed of 60-80 r/min and a temperature of 65-70°C, react for 2-3 hours, add n-butyl titanate, continue to react for 2-3 hours, heat to 120-130°C, and keep warm for 1-1.5 hours to obtain a modified filler.

Furthermore, the molar ratio of 2,2':6',2''-terpyridine-4'-carboxylic acid and anhydrous ethanol in step A1 is 1:1, the amount of p-toluenesulfonic acid used is 2,2':6',2''-terpyridine-4'-carboxylic acid, and the molar ratio of cupric chloride dihydrate and intermediate 1 is 1:1.

Furthermore, the amount ratio of the copper organic framework and the sodium hydroxide solution described in step A2 is 1g:6mL, the concentration of the sodium hydroxide solution is 6mmol/L, and the molar ratio of the carboxyl group, γ-aminopropylmethyldiethoxysilane and dicyclohexylcarbodiimide of the functionalized organic framework is 1:1:1.1.

Furthermore, the amount of KH550 described in step A3 is 3% of the mass of graphene oxide, the molar ratio of KH550 and dicyclohexylcarbodiimide is 1:1, the amount ratio of pretreated graphene, modified organic framework, dimethyldiethoxysilane, anhydrous ethanol, deionized water, hydrochloric acid solution and n-butyl titanate is 1g:3g:10mmol:30mL:40mL:10mL:5mmol, and the mass fraction of hydrochloric acid solution is 5%.

Further, the modified carrier is prepared by the following steps:

Step B1: 3,4-dihydroxybenzoic acid, glycidol, p-toluenesulfonic acid and toluene are mixed evenly, and reacted at a speed of 150-200 r/min and a temperature of 100-110° C. for 6-8 hours to obtain intermediate 2; phenylboric acid, intermediate 2, chloroform and 5A molecular sieve are mixed evenly, nitrogen is introduced for protection, and reacted at a speed of 120-150 r/min and a temperature of 60-65° C. for 10-15 hours to obtain intermediate 3;

Step B2: α-cellulose and sodium hydroxide solution are mixed, and stirred for 4-5 hours at a rotation speed of 150-200 r/min and a temperature of 50-60° C. to obtain alkalized cellulose. The alkalized cellulose, intermediate 3 and dioxane are mixed evenly, and reacted for 7-9 hours at a rotation speed of 120-150 r/min, a temperature of 70-80° C. and a pH value of 9-10 to obtain modified cellulose. The following raw materials are weighed in parts by weight: 20-30 parts of modified cellulose, 60-80 parts of diethylene glycol monobutyl ether, 5-10 parts of castor oil and 1-3 parts of stearamide, and the raw materials are mixed evenly to obtain a modified carrier.

Furthermore, the molar ratio of 3,4-dihydroxybenzoic acid and propylene oxide in step B1 is 1:1, the amount of p-toluenesulfonic acid used is 2% of the mass of 3,4-dihydroxybenzoic acid, and the amount ratio of phenylboric acid, intermediate 2 and 5A molecular sieve is 16mmol:15mmol:2g.

Furthermore, the dosage ratio of the α-cellulose and the sodium hydroxide solution in step B2 is 1 g:25 mL, the mass fraction of the sodium hydroxide solution is 15%, and the mass ratio of the alkalized cellulose and the intermediate 3 is 1:1.

Beneficial effects of the present invention: A conductive paste for a TOPCon battery prepared by the present invention comprises the following raw materials: a conductive additive, silver powder, glass powder and a modified carrier, wherein the conductive additive reacts with 2,2':6',2''-terpyridine-4'-carboxylic acid and anhydrous ethanol, so that the carboxyl group on the 2,2':6',2''-terpyridine-4'-carboxylic acid and the hydroxyl group on the anhydrous ethanol are esterified to obtain an intermediate 1, the intermediate 1 is reacted with copper chloride dihydrate, so that the terpyridine on the intermediate 1 is complexed with copper ions to form a copper organic framework, and the copper organic framework is hydrolyzed with a sodium hydroxide solution, so that the ester group on the copper organic framework is converted into The functionalized organic framework is reacted with γ-aminopropylmethyldiethoxysilane to dehydrate the carboxyl groups on the functionalized organic framework and the amino groups on the γ-aminopropylmethyldiethoxysilane to obtain a modified organic framework; the graphene oxide is reacted with KH550 to dehydrate the carboxyl groups on the graphene oxide and the amino groups on the KH550 to obtain pretreated graphene; the pretreated graphene, the modified organic framework, dimethyldiethoxysilane and n-butyl titanate are hydrolyzed and condensed to form a titanium-containing organic silicon segment to obtain a modified filler; the modified filler is sintered at a high temperature to obtain a conductive additive, wherein the conductive additive contains The copper, titanium, silicon dioxide and graphene structure can reduce the loss of electrons during transmission, and copper can also form a low-resistance ohmic contact with silicon or polysilicon, and it is easy to form a large number of shallow silver-copper spikes. The silver-copper spikes become a bridge for current transmission, achieving better ohmic contact, and can prevent the formation of silver metal spikes from penetrating the silicon substrate, and improve the capture of light, making use of light that was originally unusable, broadening the absorption range of sunlight, and improving the photoelectric conversion rate. The modified carrier uses 3,4-dihydroxybenzoic acid and propylene oxide as raw materials, so that the carboxyl group on 3,4-dihydroxybenzoic acid and the hydroxyl group on propylene oxide react , intermediate 2 is obtained, phenylboronic acid is reacted with intermediate 2, so that the boric acid group on phenylboronic acid reacts with the catechol group on intermediate 2 to obtain intermediate 3, α-cellulose is treated with sodium hydroxide solution to form alkalized cellulose, alkalized cellulose is reacted with intermediate 3, so that the epoxy group on intermediate 3 reacts with the hydroxyl group on alkalized cellulose to obtain modified fiber, modified cellulose, diethylene glycol monobutyl ether, castor oil and stearamide are mixed to obtain a modified carrier, and the modified carrier can provide boron doping during the sintering process of the conductive slurry, and can be combined with the conductive additive to increase the charge carrier flow rate, thereby improving the conductive performance.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

A production process of conductive paste for TOPCon batteries, specifically comprising the following steps:

The modified filler was placed in a tubular furnace, heated to 800°C at a heating rate of 5°C/min in a nitrogen atmosphere, and sintered for 2 hours to obtain a conductive additive. The following raw materials were weighed in parts by weight: 3 parts of conductive additive, 85 parts of silver powder, 1 part of glass powder and 9 parts of modified carrier. The raw materials were mixed evenly and ground to a fineness of 5μm to obtain a conductive slurry for TOPCon batteries.

The glass powder contains 18wt% silicon dioxide, 5wt% aluminum oxide, 26wt% boron oxide, 49% lead oxide, 1wt% calcium oxide and 1wt% magnesium oxide.

The modified filler is prepared by the following steps:

Step A1: 2,2':6',2''-terpyridine-4'-carboxylic acid, anhydrous ethanol, p-toluenesulfonic acid and toluene are mixed evenly, and reacted at a speed of 120 r/min and a temperature of 90° C. for 10 hours to obtain an intermediate 1; cupric chloride dihydrate is dissolved in anhydrous ethanol, and the intermediate 1 is added, and nitrogen is introduced for protection, and refluxed at a speed of 60 r/min and a temperature of 78° C. for 3 hours to obtain a copper organic framework;

Step A2: Disperse the copper organic framework in ethanol, add sodium hydroxide solution, and reflux for reaction at 90° C. for 10 h to obtain a functionalized organic framework; mix the functionalized organic framework, γ-aminopropylmethyldiethoxysilane, dicyclohexylcarbodiimide and toluene evenly, and react for 2 h at a speed of 150 r/min and a temperature of 40° C. to obtain a modified organic framework;

Step A3: Disperse graphene oxide in anhydrous ethanol, add KH550 and dicyclohexylcarbodiimide, react for 2 hours at a speed of 150 r/min and a temperature of 40°C to obtain pretreated graphene, mix the pretreated graphene, modified organic framework, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water and hydrochloric acid solution at a speed of 60 r/min and a temperature of 65°C, react for 2 hours, add n-butyl titanate, continue to react for 2 hours, heat to 120°C, and keep warm for 1 hour to obtain a modified filler.

The molar ratio of 2,2':6',2''-terpyridine-4'-carboxylic acid and anhydrous ethanol in step A1 is 1:1, the amount of p-toluenesulfonic acid used is 2,2':6',2''-terpyridine-4'-carboxylic acid, and the molar ratio of cupric chloride dihydrate and intermediate 1 is 1:1.

The amount ratio of the copper organic framework and the sodium hydroxide solution described in step A2 is 1g:6mL, the concentration of the sodium hydroxide solution is 6mmol/L, and the molar ratio of the carboxyl group, γ-aminopropylmethyldiethoxysilane and dicyclohexylcarbodiimide of the functionalized organic framework is 1:1:1.1.

The amount of KH550 described in step A3 is 3% of the mass of graphene oxide, the molar ratio of KH550 and dicyclohexylcarbodiimide is 1:1, the amount ratio of pretreated graphene, modified organic framework, dimethyldiethoxysilane, anhydrous ethanol, deionized water, hydrochloric acid solution and n-butyl titanate is 1g:3g:10mmol:30mL:40mL:10mL:5mmol, and the mass fraction of hydrochloric acid solution is 5%.

The modified carrier is prepared by the following steps:

Step B1: 3,4-dihydroxybenzoic acid, propylene oxide, p-toluenesulfonic acid and toluene were mixed evenly, and the mixture was reacted at a speed of 150 r/min and a temperature of 100° C. for 6 h to obtain intermediate 2; phenylboric acid, intermediate 2, chloroform and 5A molecular sieve were mixed evenly, nitrogen was introduced for protection, and the mixture was reacted at a speed of 120 r/min and a temperature of 60° C. for 10 h to obtain intermediate 3;

Step B2: α-cellulose and sodium hydroxide solution are mixed, and stirred for 4 hours at a speed of 150 r/min and a temperature of 50° C. to obtain alkalized cellulose. The alkalized cellulose, intermediate 3 and dioxane are mixed evenly, and reacted for 7 hours at a speed of 120 r/min, a temperature of 70° C. and a pH value of 9 to obtain modified cellulose. The following raw materials are weighed in parts by weight: 20 parts of modified cellulose, 60 parts of diethylene glycol monobutyl ether, 5 parts of castor oil and 1 part of stearamide, and the raw materials are mixed evenly to obtain a modified carrier.

The molar ratio of 3,4-dihydroxybenzoic acid and propylene oxide in step B1 is 1:1, the amount of p-toluenesulfonic acid used is 2% of the mass of 3,4-dihydroxybenzoic acid, and the amount ratio of phenylboric acid, intermediate 2 and 5A molecular sieve is 16mmol:15mmol:2g.

The dosage ratio of α-cellulose and sodium hydroxide solution in step B2 is 1 g:25 mL, the mass fraction of sodium hydroxide solution is 15%, and the mass ratio of alkalized cellulose and intermediate 3 is 1:1.

Example 2

A production process of conductive paste for TOPCon batteries, specifically comprising the following steps:

The modified filler was placed in a tubular furnace, heated to 830°C at a heating rate of 5°C/min in a nitrogen atmosphere, and sintered for 2.5 hours to obtain a conductive additive. The following raw materials were weighed in parts by weight: 4 parts of conductive additive, 88 parts of silver powder, 3 parts of glass powder and 9.5 parts of modified carrier. The raw materials were mixed evenly and ground to a fineness of 5μm to obtain a conductive slurry for TOPCon batteries.

The glass powder contains 18wt% silicon dioxide, 5wt% aluminum oxide, 26wt% boron oxide, 49% lead oxide, 1wt% calcium oxide and 1wt% magnesium oxide.

The modified filler is prepared by the following steps:

Step A1: 2,2':6',2''-terpyridine-4'-carboxylic acid, anhydrous ethanol, p-toluenesulfonic acid and toluene are mixed evenly, and reacted at a speed of 120 r/min and a temperature of 95° C. for 13 hours to obtain intermediate 1, and cupric chloride dihydrate is dissolved in anhydrous ethanol, and intermediate 1 is added, and nitrogen protection is introduced, and reflux reaction is carried out at a speed of 60 r/min and a temperature of 79° C. for 4 hours to obtain a copper organic framework;

Step A2: Disperse the copper organic framework in ethanol, add sodium hydroxide solution, and reflux for reaction at 93° C. for 13 h to obtain a functionalized organic framework; uniformly mix the functionalized organic framework, γ-aminopropylmethyldiethoxysilane, dicyclohexylcarbodiimide and toluene, and react for 2.5 h at a speed of 150 r/min and a temperature of 45° C. to obtain a modified organic framework;

Step A3: Disperse graphene oxide in anhydrous ethanol, add KH550 and dicyclohexylcarbodiimide, react for 2.5 hours at a speed of 150 r/min and a temperature of 45°C to obtain pretreated graphene, mix the pretreated graphene, modified organic framework, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water and hydrochloric acid solution at a speed of 60 r/min and a temperature of 68°C, react for 2 hours, add n-butyl titanate, continue to react for 3 hours, heat to 125°C, and keep warm for 1.3 hours to obtain a modified filler.

The molar ratio of 2,2':6',2''-terpyridine-4'-carboxylic acid and anhydrous ethanol in step A1 is 1:1, the amount of p-toluenesulfonic acid used is 2,2':6',2''-terpyridine-4'-carboxylic acid, and the molar ratio of cupric chloride dihydrate and intermediate 1 is 1:1.

The amount ratio of the copper organic framework and the sodium hydroxide solution described in step A2 is 1g:6mL, the concentration of the sodium hydroxide solution is 6mmol/L, and the molar ratio of the carboxyl group, γ-aminopropylmethyldiethoxysilane and dicyclohexylcarbodiimide of the functionalized organic framework is 1:1:1.1.

The amount of KH550 described in step A3 is 3% of the mass of graphene oxide, the molar ratio of KH550 and dicyclohexylcarbodiimide is 1:1, the amount ratio of pretreated graphene, modified organic framework, dimethyldiethoxysilane, anhydrous ethanol, deionized water, hydrochloric acid solution and n-butyl titanate is 1g:3g:10mmol:30mL:40mL:10mL:5mmol, and the mass fraction of hydrochloric acid solution is 5%.

The modified carrier is prepared by the following steps:

Step B1: 3,4-dihydroxybenzoic acid, propylene oxide, p-toluenesulfonic acid and toluene were mixed evenly, and the mixture was reacted at a speed of 150 r/min and a temperature of 105° C. for 7 h to obtain intermediate 2; phenylboric acid, intermediate 2, chloroform and 5A molecular sieve were mixed evenly, nitrogen was introduced for protection, and the mixture was reacted at a speed of 120 r/min and a temperature of 65° C. for 13 h to obtain intermediate 3;

Step B2: α-cellulose and sodium hydroxide solution are mixed, and stirred for 4.5 hours at a speed of 150 r/min and a temperature of 55° C. to obtain alkalized cellulose. The alkalized cellulose, intermediate 3 and dioxane are mixed evenly, and reacted for 8 hours at a speed of 120 r/min, a temperature of 75° C. and a pH value of 10 to obtain modified cellulose. The following raw materials are weighed in parts by weight: 25 parts of modified cellulose, 70 parts of diethylene glycol monobutyl ether, 8 parts of castor oil and 2 parts of stearamide, and the raw materials are mixed evenly to obtain a modified carrier.

The molar ratio of 3,4-dihydroxybenzoic acid and propylene oxide in step B1 is 1:1, the amount of p-toluenesulfonic acid used is 2% of the mass of 3,4-dihydroxybenzoic acid, and the amount ratio of phenylboric acid, intermediate 2 and 5A molecular sieve is 16mmol:15mmol:2g.

The dosage ratio of α-cellulose and sodium hydroxide solution in step B2 is 1 g:25 mL, the mass fraction of sodium hydroxide solution is 15%, and the mass ratio of alkalized cellulose and intermediate 3 is 1:1.

Example 3

A production process of conductive paste for TOPCon batteries, specifically comprising the following steps:

The modified filler was placed in a tubular furnace, heated to 850°C at a heating rate of 5°C/min in a nitrogen atmosphere, and sintered for 3 hours to obtain a conductive additive. The following raw materials were weighed in parts by weight: 5 parts of conductive additive, 90 parts of silver powder, 5 parts of glass powder and 10 parts of modified carrier. The raw materials were mixed evenly and ground to a fineness of 5μm to obtain a conductive slurry for TOPCon batteries.

The glass powder contains 18wt% silicon dioxide, 5wt% aluminum oxide, 26wt% boron oxide, 49% lead oxide, 1wt% calcium oxide and 1wt% magnesium oxide.

The modified filler is prepared by the following steps:

Step A1: 2,2':6',2''-terpyridine-4'-carboxylic acid, anhydrous ethanol, p-toluenesulfonic acid and toluene are mixed evenly, and reacted for 15 hours at a speed of 150 r/min and a temperature of 100° C. to obtain an intermediate 1, and cupric chloride dihydrate is dissolved in anhydrous ethanol, and the intermediate 1 is added, and nitrogen protection is introduced, and reflux reaction is carried out for 5 hours at a speed of 80 r/min and a temperature of 80° C. to obtain a copper organic framework;

Step A2: Disperse the copper organic framework in ethanol, add sodium hydroxide solution, and reflux for reaction at 95° C. for 15 h to obtain a functionalized organic framework; uniformly mix the functionalized organic framework, γ-aminopropylmethyldiethoxysilane, dicyclohexylcarbodiimide and toluene, and react for 3 h at a speed of 200 r/min and a temperature of 50° C. to obtain a modified organic framework;

Step A3: Disperse graphene oxide in anhydrous ethanol, add KH550 and dicyclohexylcarbodiimide, react for 3 hours at a speed of 200 r/min and a temperature of 50°C to obtain pretreated graphene, mix the pretreated graphene, modified organic framework, dimethyldiethoxysilane and anhydrous ethanol evenly, stir and add deionized water and hydrochloric acid solution at a speed of 80 r/min and a temperature of 70°C, react for 3 hours, add n-butyl titanate, continue to react for 3 hours, heat to 130°C, and keep warm for 1.5 hours to obtain a modified filler.

The molar ratio of 2,2':6',2''-terpyridine-4'-carboxylic acid and anhydrous ethanol in step A1 is 1:1, the amount of p-toluenesulfonic acid used is 2,2':6',2''-terpyridine-4'-carboxylic acid, and the molar ratio of cupric chloride dihydrate and intermediate 1 is 1:1.

The amount ratio of the copper organic framework and the sodium hydroxide solution described in step A2 is 1g:6mL, the concentration of the sodium hydroxide solution is 6mmol/L, and the molar ratio of the carboxyl group, γ-aminopropylmethyldiethoxysilane and dicyclohexylcarbodiimide of the functionalized organic framework is 1:1:1.1.

The amount of KH550 described in step A3 is 3% of the mass of graphene oxide, the molar ratio of KH550 and dicyclohexylcarbodiimide is 1:1, the amount ratio of pretreated graphene, modified organic framework, dimethyldiethoxysilane, anhydrous ethanol, deionized water, hydrochloric acid solution and n-butyl titanate is 1g:3g:10mmol:30mL:40mL:10mL:5mmol, and the mass fraction of hydrochloric acid solution is 5%.

The modified carrier is prepared by the following steps:

Step B1: 3,4-dihydroxybenzoic acid, propylene oxide, p-toluenesulfonic acid and toluene were mixed evenly, and the mixture was reacted at a speed of 200 r/min and a temperature of 110° C. for 8 h to obtain intermediate 2; phenylboric acid, intermediate 2, chloroform and 5A molecular sieve were mixed evenly, nitrogen was introduced for protection, and the mixture was reacted at a speed of 150 r/min and a temperature of 65° C. for 15 h to obtain intermediate 3;

Step B2: α-cellulose and sodium hydroxide solution are mixed, and stirred for 5 hours at a speed of 200 r/min and a temperature of 60° C. to obtain alkalized cellulose. The alkalized cellulose, intermediate 3 and dioxane are mixed evenly, and reacted for 9 hours at a speed of 150 r/min, a temperature of 80° C. and a pH value of 10 to obtain modified cellulose. The following raw materials are weighed in parts by weight: 30 parts of modified cellulose, 80 parts of diethylene glycol monobutyl ether, 10 parts of castor oil and 3 parts of stearamide, and the raw materials are mixed evenly to obtain a modified carrier.

The molar ratio of 3,4-dihydroxybenzoic acid and propylene oxide in step B1 is 1:1, the amount of p-toluenesulfonic acid used is 2% of the mass of 3,4-dihydroxybenzoic acid, and the amount ratio of phenylboric acid, intermediate 2 and 5A molecular sieve is 16mmol:15mmol:2g.

The dosage ratio of α-cellulose and sodium hydroxide solution in step B2 is 1 g:25 mL, the mass fraction of sodium hydroxide solution is 15%, and the mass ratio of alkalized cellulose and intermediate 3 is 1:1.

Comparative Example 1

Compared with Example 1, this comparative example uses α-cellulose instead of modified cellulose, and the other steps are the same.

Comparative Example 2

Compared with Example 1, this comparative example did not add a modified organic framework, and the remaining steps were the same.

Comparative Example 3

Compared with Example 1, this comparative example uses a copper organic framework instead of a modified filler, and the remaining steps are the same.

The conductive pastes prepared in Examples 1-3 and Comparative Examples 1-3 were respectively printed on n-type TOPCon cell silicon wafers with a size of 182 mm×182 mm using a Baccini screen printer, and then sintered under argon protection at a peak temperature of 830° C. to obtain electrode sheets. The contact resistance and conversion efficiency thereof were tested using a German Berger tester PSS10-HE. The test results are shown in Table 1 below.

Table 1

It can be seen from the above table that the contact resistance of the conductive paste prepared in Examples 1-3 is 1.33-1.42 mΩ·cm ² , and the conversion efficiency is 26.14-26.61%. The contact resistance of the conductive paste prepared in Comparative Example 1 is 2.72 mΩ·cm 2 , and the conversion efficiency is 24.14%. The contact resistance of the conductive paste prepared in Comparative Example ² is 5.68 mΩ·cm ² , and the conversion efficiency is 23.07%. The contact resistance of the conductive paste prepared in Comparative Example 3 is 6.31 Ω·cm ² , and the conversion efficiency is 21.21%, indicating that the present invention has good conversion efficiency.

The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims (2)

1. A production process of conductive paste for TOPCon battery, characterized in that it specifically comprises the following steps: The modified filler is placed in a tube furnace and sintered to obtain a conductive additive. The following raw materials are weighed in parts by weight: 3-5 parts of conductive additive, 85-90 parts of silver powder, 1-5 parts of glass powder and 9-10 parts of modified carrier. The raw materials are mixed evenly and ground to a fineness of 5 μm to obtain a conductive slurry for TOPCon batteries. The modified filler is prepared by the following steps: Step A1: 2,2':6',2''-terpyridine-4'-carboxylic acid, anhydrous ethanol, p-toluenesulfonic acid and toluene are mixed for reaction to obtain intermediate 1, copper chloride dihydrate is dissolved in anhydrous ethanol, intermediate 1 is added, nitrogen is introduced for protection, and reflux reaction is performed to obtain a copper organic framework; Step A2: dispersing the copper organic framework in ethanol, adding sodium hydroxide solution, and reflux reaction to obtain a functionalized organic framework, and mixing the functionalized organic framework, γ-aminopropylmethyldiethoxysilane, dicyclohexylcarbodiimide and toluene to obtain a modified organic framework; Step A3: dispersing graphene oxide in anhydrous ethanol, adding KH550 and dicyclohexylcarbodiimide, reacting to obtain pretreated graphene, mixing the pretreated graphene, modified organic framework, dimethyldiethoxysilane and anhydrous ethanol, stirring, adding deionized water and hydrochloric acid solution, reacting, adding n-butyl titanate, continuing the reaction, heating and heat preservation treatment, and obtaining a modified filler; The modified carrier is prepared by the following steps: Step B1: 3,4-dihydroxybenzoic acid, propylene oxide, p-toluenesulfonic acid and toluene are mixed for reaction to obtain intermediate 2, phenylboric acid, intermediate 2, chloroform and 5A molecular sieve are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out to obtain intermediate 3; Step B2: α-cellulose and sodium hydroxide solution are mixed and stirred to obtain alkalized cellulose, and the alkalized cellulose, intermediate 3 and dioxane are mixed and reacted to obtain modified cellulose. The following raw materials are weighed in parts by weight: 20-30 parts of modified cellulose, 60-80 parts of diethylene glycol monobutyl ether, 5-10 parts of castor oil and 1-3 parts of stearamide, and the raw materials are mixed uniformly to obtain a modified carrier; The molar ratio of 2,2':6',2''-terpyridine-4'-carboxylic acid to anhydrous ethanol in step A1 is 1:1, and the molar ratio of cupric chloride dihydrate to intermediate 1 is 1:1; The copper organic framework and the sodium hydroxide solution in step A2 are used in a ratio of 1 g:6 mL, and the molar ratio of the carboxyl group of the functionalized organic framework, γ-aminopropylmethyldiethoxysilane and dicyclohexylcarbodiimide is 1:1:1.1; The amount of KH550 described in step A3 is 3% of the mass of graphene oxide, the molar ratio of KH550 to dicyclohexylcarbodiimide is 1:1, and the amount ratio of pretreated graphene, modified organic framework, dimethyldiethoxysilane, anhydrous ethanol, deionized water, hydrochloric acid solution and n-butyl titanate is 1g:3g:10mmol:30mL:40mL:10mL:5mmol; The molar ratio of 3,4-dihydroxybenzoic acid and glycidol in step B1 is 1:1, and the amount ratio of phenylboric acid, intermediate 2 and 5A molecular sieve is 16mmol:15mmol:2g; The usage ratio of α-cellulose and sodium hydroxide solution in step B2 is 1 g:25 mL, and the mass ratio of alkalized cellulose and intermediate 3 is 1:1. 2. A conductive paste for TOPCon battery, characterized in that it is prepared according to the production process described in claim 1.