High-performance conductive silver-aluminum paste and preparation method therefor, electrode and n-type topcon battery

Abstract

A high-performance conductive silver-aluminum paste, comprising a silver powder, an aluminum powder, a glass powder, a silver-aluminum paste additive and an organic carrier. Based on the total weight of the conductive silver-aluminum paste being 100%, the weight percentage contents of the components are: 80.0-88.0% of the silver powder, 0.5-2.0% of the aluminum powder, 2.0-6.0% of the glass powder, 0.1-2.0% of the silver-aluminum paste additive, and 8.0-12.0% of the organic carrier, wherein the glass powder comprises a first main glass powder and a second main glass powder, or comprises the first main glass powder, the second main glass powder and an auxiliary glass powder; and the first main glass powder is a Pb-Si-B-Li-O system glass powder, the second main glass powder is a Pb-Bi-B-Li-O system glass powder, and the auxiliary glass powder is a Ba-B-Si-Li-O system glass powder. The conductive silver-aluminum paste has the advantages of strong aging resistance, good contact and a high photoelectric conversion efficiency. Further disclosed are a preparation method for the high-performance conductive silver-aluminum paste, an electrode and an N-type TOPCon battery.

Description

High-performance conductive silver-aluminum paste, preparation method, electrode and N-type TOPcon battery Technical Field

[0001] The present invention belongs to the field of silicon solar cells, and in particular relates to a high-performance conductive silver-aluminum paste, a preparation method, an electrode and an N-type TOPcon cell. Background Art

[0002] Solar energy is currently the world's largest and most widely distributed clean energy source, and is a hot topic for development worldwide. Silicon solar cells are one of the key means of converting solar energy into usable electrical energy, and therefore have also gained widespread application. Silicon solar cells primarily consist of a front electrode, an anti-reflection layer, a PN junction, a silicon substrate, and a back field. When light strikes the surface of a solar cell, it is fully absorbed by the anti-reflection layer and then enters the PN junction. Absorbed by the PN junction, the photon undergoes a photoelectric effect, releasing electrons. These electrons are then conducted by the surface electrons to form an electric current, converting light energy into electrical energy.

[0003] The electrodes of silicon solar cells are typically screen-printed with a conductive paste onto the cell surface, which is then sintered to form conductive silver grid lines. Currently, the conductive paste used on the front of mainstream Se-perc cells is primarily silver paste, while the newer N-type TOPcon cells primarily use silver-aluminum paste. Because the development of new N-type TOPcon cells is still in its early stages, the development of silver-aluminum paste for these cells is not yet mature.

[0004] Conductive silver-aluminum paste generally includes silver powder, aluminum powder, glass powder, organic carrier and other parts. Silver powder and aluminum powder mainly play the role of conduction and contact formation; organic carrier is a solution of polymer (such as resin and cellulose, etc.) dissolved in an organic solvent. It is a carrier of the conductive phase and the adhesive phase, and plays the role of dispersing the conductive phase and the adhesive phase, and mixing the conductive phase and the adhesive phase for screen printing; glass powder mainly plays the role of corroding the anti-reflection film, promoting the conductive phase to form contact, and assisting in sintering and bonding the conductive phase and the substrate.

[0005] Because solar cell encapsulation materials contain certain organic substances, such as EVA, these substances produce acids, such as acetic acid, under long-term sunlight. These substances can corrode the surface electrodes of silicon solar cells, causing problems such as electrode shedding and poor contact, reducing the photoelectric conversion efficiency of silicon solar cells and seriously shortening their service life. Therefore, high-performance conductive silver-aluminum paste must have excellent contact with the cell substrate, minimal damage to the cell's PN junction, and resistance to aging and shedding. Excellent contact with the cell substrate and minimal damage to the cell's PN junction enable the cell to have excellent photoelectric conversion efficiency, and resistance to aging and shedding can extend the battery's service life. Judging from the current state of industry development, the development of a silver-aluminum paste with good aging resistance and excellent electrical properties is also urgently needed.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to provide a high-performance conductive silver-aluminum paste, a preparation method, an electrode, and an N-type TOPcon battery, which achieves a conductive silver-aluminum paste with strong aging resistance, excellent contact, and high photoelectric conversion efficiency. To achieve the above objectives, the technical solutions adopted by the present invention are as follows:

[0008] A high-performance conductive silver-aluminum paste, comprising silver powder, aluminum powder, glass powder, a silver-aluminum paste additive, and an organic carrier. Based on the total weight of the conductive silver-aluminum paste being 100%, the weight percentage of each component is as follows:

[0009] Silver powder 80.0%~88.0%;

[0010] Aluminum powder 0.5% to 2.0%;

[0011] Glass powder 2.0% to 6.0%;

[0012] Silver aluminum paste additive 0.1% ~ 2.0%;

[0013] Organic carrier 8.0% to 12.0%;

[0014] Among them, the glass powder includes a first main glass powder and a second main glass powder, or includes a first main glass powder, a second main glass powder and an auxiliary glass powder; the first main glass powder is a Pb-Si-B-Li-O system glass powder, the second main glass powder is a Pb-Bi-B-Li-O system glass powder, and the auxiliary glass powder is a Ba-B-Si-Li-O system glass powder.

[0015] Furthermore, based on the total weight of the glass powder containing various components being 100%, the weight percentage of each component is as follows:

[0016] The first main glass powder and the second main glass powder are 60% to 100.0%;

[0017] Auxiliary glass powder 0.0%~40.0%.

[0018] Furthermore, in the first main glass frit, taking the total molar number of each component contained in the first main glass frit as 100%, the molar percentage of each component is as follows:

[0019] PbO 30.0%~70.0%;

[0020] SiO2 10.0%~35.0%;

[0021] B2O3 5.0%~15.0%;

[0022] Li2O 2.0%~12.0%;

[0023] The first modifying additive is 0.0% to 30.0%;

[0024] The first modifying additive is an oxide containing one or more elements selected from the group consisting of Zn, Ca, Ba, Bi, Na, K, Te, Se, Ge, Al, and Ga, or a substance that is decomposed to obtain the oxide of the element during the process of preparing the first main glass powder.

[0025] Furthermore, in the second main glass frit, taking the total molar number of each component contained in the second main glass frit as 100%, the molar percentage of each component is as follows:

[0026] PbO 5.0%~50.0%;

[0027] Bi2O3 5.0%~50.0%;

[0028] B2O3 5.0%~25.0%;

[0029] Li2O 3.0%~20.0%;

[0030] The second modified additive is 0.0% to 30.0%;

[0031] The second modifying additive is an oxide containing one or more elements of Zn, Ca, Ba, Na, K, Al, Si, Ge, Se, Te, Sn, and Ga, or a substance that decomposes to obtain the oxide of the element during the process of making the second main glass powder.

[0032] Furthermore, in the auxiliary glass powder, taking the total molar number of each component contained in the auxiliary glass powder as 100%, the molar percentage of each component is as follows:

[0033] BaO 20.0%~40.0%;

[0034] B2O3 5.0%~30.0%;

[0035] SiO2 20.0%~50.0%;

[0036] Li2O 12.0%~30.0%;

[0037] Auxiliary modification additives 0.0% to 20.0%;

[0038] The auxiliary modifying additive is an oxide containing one or more elements selected from Pb, Bi, Al, Ga, K, Na, and Tl, or a substance that is decomposed to obtain the oxide of the element during the process of preparing the auxiliary glass powder.

[0039] Furthermore, the silver-aluminum paste additive is at least one of a silver-aluminum paste additive containing boron elements or a silver-aluminum paste additive containing zinc elements; the silver-aluminum paste additive containing boron elements is one or more of boron nitride, boron carbide, boron powder, aluminum boride, silicon boride, tungsten boride, and molybdenum boride; the silver-aluminum paste additive containing zinc elements is one or more of zinc powder, zinc oxide, zinc titanate, zinc stearate, and zinc palmitate.

[0040] Furthermore, the particle sizes of the silver powder, the aluminum powder, the glass powder and the silver-aluminum paste additive powder do not exceed 8 μm.

[0041] Furthermore, the organic vehicle comprises an organic solvent, an organic resin and an additive. Based on the total weight of the organic vehicle being 100%, the content of each component is as follows:

[0042] Organic solvent 60.0%~80.0%;

[0043] Organic resin 5.0% to 25.0%;

[0044] Additives 1.0%~25.0%.

[0045] The present invention also provides a method for preparing the high-performance conductive silver-aluminum paste described above, comprising the following steps:

[0046] Preparation of the first main glass powder, the second main glass powder and the auxiliary glass powder: the raw materials for the first main glass powder are weighed and mixed according to a set ratio, and then melted at high temperature, cooled and dried, and then crushed to obtain the required first main glass powder; the raw materials for the second main glass powder are weighed and mixed according to a set ratio, and then melted at high temperature, cooled and dried, and then crushed to obtain the required second main glass powder; the raw materials for the auxiliary glass powder are weighed and mixed according to a set ratio, and then melted at high temperature, cooled and dried, and then crushed to obtain the required auxiliary glass powder.

[0047] Preparation of organic carrier: weighing the raw materials for the organic carrier according to a set ratio, heating and stirring to mix, high-speed centrifugation to disperse uniformly, and then filtering to obtain the organic carrier;

[0048] Preparation of conductive silver-aluminum paste: silver powder, aluminum powder, glass powder, and silver-aluminum paste additives are added to the prepared organic vehicle according to mass ratio, mixed and stirred evenly, and then ground, adjusted in viscosity, and filtered to obtain the conductive silver-aluminum paste.

[0049] The present invention also provides an electrode, which is formed by sintering the high-performance conductive silver-aluminum paste mentioned above on the surface of a battery silicon wafer.

[0050] The present invention also provides a TOPcon battery comprising the above-mentioned electrode.

[0051] The beneficial effects of the present invention are as follows:

[0052] First, the conductive silver-aluminum paste of the present invention uses glass powders of different systems, which are composed of three glass powder systems: a first main glass powder, a second main glass powder, and an auxiliary glass powder. The first main glass powder and the second main glass powder are essential components, and the auxiliary glass powder is an auxiliary component, which can be added optionally.

[0053] The first main glass powder is a Pb-Si-B-Li-O system glass powder, which uses a large amount of Si and Pb elements and a relatively low amount of Li element. A large amount of Si element is used to act as a glass structure to reduce the proportion of the easily hydrolyzed element B in the glass structure, which can effectively reduce the degree of hydrolysis of the glass structure in acidic and alkaline environments and improve the anti-hydrolysis stability of the silver-aluminum paste. The use of a relatively low amount of alkali metal Li further reduces the degree of hydrolysis of the glass in acidic and alkaline environments and improves the anti-hydrolysis stability of the silver-aluminum paste. The use of a large amount of Pb element can effectively reduce the softening point of the first main glass powder and the viscosity of the glass liquid, so that the glass liquid still has excellent corrosiveness under low alkali conditions. This not only can effectively etch the insulating anti-reflection film on the surface of the battery, but also can effectively assist in the sintering of silver and aluminum powders.

[0054] The second main glass powder is a Pb-Bi-B-Li-O system glass powder. It is a high-bismuth glass with a higher softening point than the first main glass powder. At the same time, high-bismuth glass can effectively inhibit glass hydrolysis, and the BO-Bi structure can effectively dissolve aluminum oxide. This not only further reduces the degree of hydrolysis of silver aluminum paste in acidic and alkaline environments, but also effectively removes aluminum oxide on the surface of aluminum powder, promoting the formation of Ag-Al-Si alloy and reducing contact resistance.

[0055] The auxiliary glass powder is a Ba-B-Si-Li-O system glass powder. Due to the strong alkalinity of Ba element oxide and the appropriate addition of B and Li, the auxiliary glass powder has a good aluminum oxide dissolving effect. When used, it can effectively remove aluminum oxide on the surface of aluminum powder, promote the formation of Ag-Al-Si alloy, and improve the contact effect.

[0056] Therefore, the combined use of the first main glass powder, the second main glass powder and the auxiliary glass powder system glass powder not only makes the silver-aluminum paste have an excellent contact effect, but also reduces the hydrolysis degree of the silver-aluminum paste, and improves the stability and anti-aging strength of the silver-aluminum paste;

[0057] Secondly, the silver-aluminum paste of the present invention uses a specific silver-aluminum paste additive, which can quickly promote the alloying of aluminum powder and silver powder and the formation of P++ region in the silver-aluminum paste, thereby further improving the contact effect of the silver-aluminum paste and enhancing the photoelectric conversion efficiency of the silver-aluminum paste;

[0058] Thus, the present invention realizes the silver-aluminum paste for N-type TOPcon silicon solar cells with strong anti-aging ability, excellent contact and high photoelectric conversion efficiency.

[0059] DETAILED DESCRIPTION

[0060] The present invention provides a high-performance conductive silver-aluminum paste. The conductive silver-aluminum paste comprises silver powder, aluminum powder, glass powder, a silver-aluminum paste additive, and an organic carrier. Based on the total weight of the conductive silver-aluminum paste being 100%, the weight percentage of each component is as follows:

[0061] Silver powder 80.0%~88.0%;

[0062] Aluminum powder 0.5% to 2.0%;

[0063] Glass powder 2.0% to 6.0%;

[0064] Silver aluminum paste additive 0.1% ~ 2.0%;

[0065] Organic carrier 8.0% to 12.0%;

[0066] The glass powder is a combination of glass powders of different systems, and the combined glass powder includes glass powders of three systems: a first main glass powder, a second main glass powder, and an auxiliary glass powder. The first and second main glass powders are required components, while the auxiliary glass powder is an auxiliary component and can be added optionally. That is, the glass powder can include the first and second main glass powders, or the first, second, and auxiliary glass powders. The first main glass powder is a Pb-Si-B-Li-O system glass powder, the second main glass powder is a Pb-Bi-B-Li-O system glass powder, and the auxiliary glass powder is a Ba-B-Si-Li-O system glass powder.

[0067] Specifically: First, the first main glass powder is a Pb-Si-B-Li-O system glass powder, which uses a large amount of Si and Pb elements and a relatively low amount of Li element. A large amount of Si element is used to act as a glass structure to reduce the proportion of the easily hydrolyzed element B in the glass structure, which can effectively reduce the degree of hydrolysis of the glass structure in acidic and alkaline environments and improve the anti-hydrolysis stability of the silver-aluminum paste. The use of a relatively low amount of alkali metal Li further reduces the degree of hydrolysis of the glass in acidic and alkaline environments and improves the anti-hydrolysis stability of the silver-aluminum paste. The use of a large amount of Pb element can effectively reduce the softening point of the first main glass powder and the viscosity of the glass liquid, so that the glass liquid still has excellent corrosiveness under low alkali conditions. This not only can effectively etch the insulating anti-reflection film on the surface of the battery, but also can effectively assist in the sintering of silver powder and aluminum powder.

[0068] The second main glass powder is a Pb-Bi-B-Li-O system glass powder. It is a high-bismuth glass with a higher softening point than the first main glass powder. At the same time, high-bismuth glass can effectively inhibit glass hydrolysis, and the BO-Bi structure can effectively dissolve aluminum oxide. This not only further reduces the degree of hydrolysis of silver aluminum paste in acidic and alkaline environments, but also effectively removes aluminum oxide on the surface of aluminum powder, promoting the formation of Ag-Al-Si alloy and reducing contact resistance.

[0069] The auxiliary glass powder is a Ba-B-Si-Li-O system glass powder. Due to the strong alkalinity of Ba element oxide and the appropriate addition of B and Li, the auxiliary glass powder has a good aluminum oxide dissolving effect. When used, it can effectively remove aluminum oxide on the surface of aluminum powder, promote the formation of Ag-Al-Si alloy, and improve the contact effect. The auxiliary glass powder can be added according to the combination of the first main glass powder and the second main glass powder to play a balancing role.

[0070] Therefore, the combined use of the first main glass powder, the second main glass powder and the auxiliary glass powder system glass powder not only makes the silver-aluminum paste have excellent contact effect, but also reduces the degree of hydrolysis of the silver-aluminum paste and improves the stability and anti-aging strength of the silver-aluminum paste.

[0071] Secondly, by adding specific silver-aluminum paste additives, the alloying of aluminum powder and silver powder and the formation of P++ area in the silver-aluminum paste can be quickly promoted, which can further improve the contact effect of the silver-aluminum paste and enhance the photoelectric conversion efficiency of the silver-aluminum paste.

[0072] Furthermore, based on the total weight of the glass powder including the components being 100%, the weight percentage of the components is as follows:

[0073] The first main glass powder and the second main glass powder are 60% to 100.0%;

[0074] Auxiliary glass powder 0.0%~40.0%.

[0075] Among them, when the glass powder contains only the first main glass powder and the second main glass powder, the total content of the first main glass powder and the second main glass powder is 100%, and the content of the auxiliary glass powder is 0%; when the glass powder contains the first main glass powder, the second main glass powder and the auxiliary glass powder, the total content of the first main glass powder and the second main glass powder is greater than or equal to 60%, and the content of the auxiliary glass powder is less than or equal to 40%.

[0076] Furthermore, in the first main glass frit, taking the total molar number of each component contained in the first main glass frit as 100%, the corresponding molar percentage of each component is as follows:

[0077] PbO 30.0%~70.0%;

[0078] SiO2 10.0%~35.0%;

[0079] B2O3 5.0%~15.0%;

[0080] Li2O 2.0%~12.0%;

[0081] The first modifying additive is 0.0% to 30.0%;

[0082] The first modifying additive is an oxide of one or more of the following elements: Zn, Ca, Ba, Bi, Na, K, Te, Se, Ge, Al, and Ga, or a substance that decomposes during the preparation of the first main glass frit to produce an oxide of one or more of these elements, such as a carbonate, peroxide, or complex. Of course, PbO, SiO2, B2O3, and Li2O can also be introduced as peroxides, carbonates, or complexes of the corresponding elements.

[0083] Furthermore, in the second main glass frit, taking the total molar number of each component contained in the second main glass frit as 100%, the corresponding molar percentage of each component is as follows:

[0084] PbO 5.0%~50.0%;

[0085] Bi2O3 5.0%~50.0%;

[0086] B2O3 5.0%~25.0%;

[0087] Li2O 3.0%~20.0%;

[0088] The second modified additive is 0.0% to 30.0%;

[0089] Among them, the second modifying additive is an oxide containing one or more elements of Zn, Ca, Ba, Na, K, Al, Si, Ge, Se, Te, Sn, and Ga, or a substance that decomposes to obtain the oxide of the element during the process of making the second main glass powder, such as a carbonate, peroxide or complex; of course, PbO, Bi2O3, B2O3 and Li2O can also be introduced as peroxides, carbonates or complexes of the corresponding elements.

[0090] Furthermore, in the auxiliary glass frit, taking the total molar number of each component contained in the auxiliary glass frit as 100%, the corresponding molar percentage of each component is as follows:

[0091] BaO 20.0%~40.0%;

[0092] B2O3 5.0%~30.0%;

[0093] SiO2 20.0%~50.0%;

[0094] Li2O 12.0%~30.0%;

[0095] Auxiliary modification additives 0.0% to 20.0%;

[0096] Among them, the auxiliary modifying additives are oxides containing one or more elements among Pb, Bi, Al, Ga, K, Na, and Tl, or substances that decompose to obtain oxides of the elements during the process of making the auxiliary glass powder, such as carbonates, peroxides, or complexes; of course, BaO, B2O3, SiO2, and Li2O can also be introduced as peroxides, carbonates, or complexes of the corresponding elements.

[0097] Furthermore, the silver-aluminum paste additive is at least one of a boron-containing silver-aluminum paste additive or a zinc-containing silver-aluminum paste additive; the boron-containing silver-aluminum paste additive is one or more of boron nitride, boron carbide, boron powder, aluminum boride, silicon boride, tungsten boride, and molybdenum boride; and the zinc-containing silver-aluminum paste additive is one or more of zinc powder, zinc oxide, zinc titanate, zinc stearate, and zinc palmitate. The present invention, by adding the boron-containing silver-aluminum paste additive and / or the zinc-containing silver-aluminum paste additive in powder form, can rapidly promote the alloying of aluminum powder and silver powder and the formation of P++ regions in the silver-aluminum paste, thereby further improving the contact effect of the silver-aluminum paste and enhancing the photoelectric conversion efficiency of the silver-aluminum paste.

[0098] Furthermore, the silver powder, aluminum powder, glass powder, and silver-aluminum paste additive powder can be selected as spherical powder or quasi-spherical powder, and the maximum particle size of the silver powder, aluminum powder, glass powder, and silver-aluminum paste additive powder does not exceed 8 μm.

[0099] Furthermore, the organic vehicle comprises an organic solvent, an organic resin and an additive. Based on the total weight of the organic vehicle being 100%, the content of each component is as follows:

[0100] Organic solvent 60.0%~80.0%;

[0101] Organic resin 5.0% to 25.0%;

[0102] Additives 1.0%~25.0%;

[0103] Among them, the organic solvent is one or more of diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, alcohol ester dodecaphosphate, dimethyl phthalate, ethylene glycol butyl ether ester, tripropylene glycol monomethyl ether, diethylene glycol butyl ether, and pentaerythritol triacrylate; the organic resin is one or more of SEPS resin, SEBS resin, polyvinyl butyral resin, poly-α-methylstyrene resin, petroleum resin, acrylic resin, cellulose acetate butyrate, carboxymethyl cellulose, and hydroxyethyl cellulose; the additive is one or more of silicone oil, palmitic acid, lithium stearate, polyamide wax, and hydrogenated castor oil.

[0104] The present invention also provides a method for preparing a high-performance conductive silver-aluminum paste, comprising the following steps:

[0105] Preparation of the first main glass powder, the second main glass powder and the auxiliary glass powder: the raw materials of the first main glass powder are weighed according to a set ratio, and then mixed evenly by ball milling or sieving, and then placed in a crucible, and then the crucible is placed in a high-temperature furnace and melted at 800°C to 1200°C for 10min to 60min. After melting evenly, the glass liquid is poured into cold water for rapid cooling to obtain glass particles, and then the glass particles are dried, preliminarily crushed, and then finely crushed to obtain the required first main glass powder with a suitable particle size; according to the above method for preparing the first main glass powder, the raw materials for the second main glass powder are weighed according to a set ratio, mixed, and then melted at high temperature, cooled and dried, and then crushed to obtain the required second main glass powder; according to the above method for preparing the first main glass powder, the raw materials for the auxiliary glass powder are weighed according to a set ratio, mixed, and then melted at high temperature, cooled and dried, and then crushed to obtain the required auxiliary glass powder;

[0106] Preparation of organic vehicle: weighing the raw materials of organic vehicle, organic solvent, organic resin, and silver-aluminum paste additive according to a set ratio, then heating and stirring in a water bath at 70°C to 100°C to mix them evenly, then dispersing them evenly through high-speed centrifugation and filtering to obtain the desired organic vehicle;

[0107] Preparation of conductive silver-aluminum paste: Add the prepared silver powder, aluminum powder, glass powder, silver-aluminum paste additive, and organic carrier into the prepared organic carrier according to the mass ratio, mix and stir evenly, then grind with three rollers, adjust the viscosity, and finally filter to obtain the required conductive silver-aluminum paste; wherein, the glass powder includes the prepared first main glass powder, the second main glass powder, or the prepared first main glass powder, the second main glass powder and the auxiliary glass powder.

[0108] The present invention also provides an electrode formed by sintering the aforementioned conductive silver-aluminum paste onto the surface of a solar cell silicon wafer. The prepared conductive silver-aluminum paste is screen-printed to form the grid lines required for the front surface of an N-type TOPcon solar cell. The electrode is then sintered to form a conductive silver gridline electrode. Other technical features of this electrode are described in the prior art and will not be elaborated upon here.

[0109] The present invention also provides a battery comprising the above-mentioned electrode. For other technical features of the battery, please refer to the prior art and will not be described in detail here.

[0110] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be understood as limiting the scope of the present invention to the following embodiments, and all technologies implemented based on the present invention fall within the scope of the present invention.

[0111] The following is explained in conjunction with specific embodiments:

[0112] Examples G101 to G106:

[0113] Preparation of the first main glass powder: The raw materials for the first main glass powder are calculated and weighed according to a predetermined formula. The mixture is then ball-milled or sieved, mixed, and placed in a crucible. The crucible is then melted in a high-temperature furnace at 800°C to 1200°C for 10 to 60 minutes. After uniform melting, the molten glass is poured into cold water for rapid cooling to produce glass particles. The glass particles are then dried, preliminarily crushed, and then finely ground to produce the desired first main glass powder of the desired particle size. The first main glass powders are numbered G101 to G106, and their specific molar compositions are shown in Table 1.

[0114] Table 1 Mole percentage of the first main glass powder (mol%)

[0115] No. G101G102G103G104G105G106PbO56.060.070.030.052.544.5SiO210.024.010.035.017.515.0B2O313.55.015.05.09.07.5Li2CO36.02.05.012.04.53.0ZnO9.04.52.0 9.015.0CaCO31.5BaCO33.0Bi2O31.012.02.0Na2CO30.5K2CO30.51.5TeO21.0SeO24.02.03.06.0GeO21.04.5Al2O30.5Ga2O31.53.0Total100.0100.0100.0100.0100.0100.0

[0116] Embodiments G201 to G206:

[0117] Preparation of the second main glass powder: The raw materials for the second main glass powder are calculated and weighed according to the specified formula. After being ball-milled or sieved, the mixture is placed in a crucible. The crucible is then melted in a high-temperature furnace at 800°C to 1200°C for 10 to 60 minutes. After uniform melting, the molten glass is poured into cold water for rapid cooling to produce glass particles. The glass particles are then dried, preliminarily crushed, and then finely ground to obtain the desired second main glass powder particle size. The second main glass powders are numbered G201 to G206, and their specific molar compositions are shown in Table 2.

[0118] Table 2 Mole percentage of the second main glass powder (mol%)

[0119] No. G201G202G203G204G205G206PbO35.05.050.040.030.035.0Bi2O318.050.05.010.015.035.0B2O319.525.012.015.05.021.0Li2CO310.59.03.07.520.09.0ZnO7.03015 .06.0CaCO32.04.0BaCO31.53.0Na2CO31.0K2CO31.5Al2O30.51.0SiO210.06.010.59.022.0GeO24.0SeO23.0TeO23.0SnO21.0Ga2O31.5Total100.0100.0100.0100.0100.0100.0

[0120] Examples G301 to G306:

[0121] Preparation of auxiliary glass powder: The raw materials for the auxiliary glass powder are calculated and weighed according to the specified formula. After being ball-milled or sieved, the mixture is uniformly mixed and placed in a crucible. The crucible is then melted in a high-temperature furnace at 800°C to 1200°C for 10 to 60 minutes. After uniform melting, the glass liquid is poured into cold water for rapid cooling to obtain glass particles. The glass particles are then dried, preliminarily crushed, and then finely ground to obtain the desired auxiliary glass powder particle size. The auxiliary glass powders are numbered G301 to G306, and their specific molar compositions are shown in Table 3.

[0122] Table 3 Mole percentage of auxiliary glass powder (mol%)

[0123] No. G301G302G303G304G305G306BaCO332.020.027.524.040.022.5B2O330.05.013.09.021.021.0SiO220.050.027.530.021.031.5Li2CO318.024.012.030.015.021.0PbO1.010.54.51.0Bi2O33.01.52.0Al2O30.5Ga2O31.50.5K2CO32.0Na2CO33.00.5Tl2O33.00.5Total 100.0100.0100.0100.0100.0100.0

[0124] Examples C101 to C106:

[0125] Preparation of organic carrier: The raw materials of organic carrier, organic solvent, organic resin and additive are weighed according to the set ratio, then heated and stirred in a water bath at 70℃~100℃ to mix evenly, and then dispersed evenly by high-speed centrifugation and filtered to obtain the required organic carrier, numbered C101~C106 for standby use. The mass composition ratio of each organic carrier is shown in Table 4.

[0126] Table 4 Organic carrier weight composition (wt%)

[0127]

[0128] Examples G01-G15:

[0129] Preparation of Conductive Silver-Aluminum Paste: Silver powder is numbered Ag1, aluminum powder is numbered Al1, and boron-containing silver-aluminum paste additives of appropriate particle size are numbered B01 to B07, with boron nitride, boron carbide, boron powder, aluminum boride, silicon boride, tungsten boride, and molybdenum boride being numbered B01 to B07, respectively. Zinc-containing silver-aluminum paste additives of appropriate particle size are numbered Z01 to Z05, with zinc powder, zinc oxide, zinc titanate, zinc stearate, and zinc palmitate being numbered Z01 to Z05, respectively. According to the material combinations and mass percentages selected in Table 5, the corresponding silver powder, aluminum powder, glass powder, and silver-aluminum paste additives are weighed and added sequentially to an organic vehicle of the corresponding type and mass. The mixture is mixed and stirred to uniform consistency, then slurried using a three-roll mill and filtered to obtain a coarse slurry. After further slurry adjustment, conductive silver-aluminum pastes G01 to G15 are obtained. The specific weight compositions of the silver-aluminum pastes are shown in Table 5.

[0130] Table 5 Weight composition of silver aluminum paste (wt%)

[0131]

[0132]

[0133] Table 5: Weight composition of silver aluminum paste (wt%)

[0134]

[0135]

[0136] Test example:

[0137] The silver-aluminum pastes prepared in Examples G01-G15 above were screen-printed onto the surface of N-type TOPcon cells, then dried, sintered, and cooled to obtain cells containing printed silver grid electrodes. The resulting cells were tested for photoelectric conversion efficiency. Furthermore, the prepared silicon solar cells were exposed to a sealed environment containing a 3% saturated potassium chloride acetate solution. Air in the sealed environment was circulated for 10 hours at 85°C using a fan. The fan was then turned off and the sealed environment cooled to room temperature. The silicon solar cells were then removed and the photoelectric conversion efficiency of the cells was tested after the experiment. The differences in cell efficiency before and after the experiment were compared, and the percentage attenuation of the photoelectric efficiency of these cells was calculated. To facilitate observation of the electrical performance characteristics of the silver-aluminum pastes of the present invention, silver-aluminum pastes 995PFB-V80 and 995PFB-V90 produced by Shanghai Silver Paste Technology Co., Ltd. were selected and printed, sintered, and tested for electrical performance under the same conditions for comparison with the silver-aluminum pastes of the present invention. The test results are shown in Table 6.

[0138] Table 6 Silver aluminum paste test data

[0139]

[0140] It can be seen from Table 6 that by comparing Examples G01-G15 of the present invention and the silver-aluminum pastes 995PFB-V80 and 996PFB-V90 produced by Shanghai Silver Paste Technology Co., Ltd., it is found that: 995PFB-V80 has better photoelectric conversion efficiency, but its acetic acid test attenuation is large and its aging resistance is poor; 996PFB-V90 has poor photoelectric conversion efficiency, but its acetic acid test attenuation is small and its aging resistance is good; compared with the silver-aluminum paste G01-G15 of the present invention, the silver-aluminum paste battery of the present invention has a higher open circuit voltage, better contact resistance, high photoelectric conversion efficiency, and low acetic acid test attenuation rate. This shows that the silver-aluminum paste provided by the present invention has high photoelectric conversion efficiency, low acetic acid test attenuation rate, and strong aging resistance.

[0141] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0142] The foregoing description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed herein are intended to be encompassed within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A high-performance conductive silver-aluminum paste, characterized in that: The conductive silver-aluminum paste comprises silver powder, aluminum powder, glass powder, a silver-aluminum paste additive and an organic carrier. Taking the total weight of the conductive silver-aluminum paste as 100%, the weight percentage of each component is as follows: Silver powder 80.0%~88.0%; Aluminum powder 0.5%~2.0%; Glass powder 2.0%~6.0%; Silver aluminum paste additive 0.1%~2.0%; Organic carrier 8.0%~12.0%; Wherein, the glass powder includes a first main glass powder and a second main glass powder, or includes a first main glass powder, a second main glass powder and an auxiliary glass powder; the first main glass powder is a Pb-Si-B-Li-O system glass powder, the second main glass powder is a Pb-Bi-B-Li-O system glass powder, and the auxiliary glass powder is a Ba-B-Si-Li-O system glass powder; Taking the total weight of the glass powder containing various components as 100%, the weight percentage of each component is: The first main glass powder and the second main glass powder 60% to 100.0%; Auxiliary glass powder 0.0%~40.0%; In the second main glass powder, taking the total molar number of each component contained in the second main glass powder as 100%, the molar percentage of each component is as follows: PbO 5.0%~50.0%; Bi2O3 5.0%~50.0%; B2O3 5.0%~25.0%; Li2O 3.0%~20.0%; The second modified additive 0.0% to 30.0%; Among them, the second modifying additive is an oxide containing one or more elements of Zn, Ca, Ba, Na, K, Al, Si, Ge, Se, Te, Sn, and Ga, or a substance that is decomposed to obtain the oxide of the element during the process of making the second main glass powder.

2. The high performance conductive silver aluminum paste according to claim 1, characterized in that: In the first main glass powder, taking the total molar number of each component contained in the first main glass powder as 100%, the molar percentage of each component is as follows: PbO 30.0%~70.0%; SiO2 10.0%~35.0%; B2O3 5.0%~15.0%; Li2O 2.0%~12.0%; The first modification additive is 0.0% to 30.0%; Among them, the first modifying additive is an oxide containing one or more elements of Zn, Ca, Ba, Bi, Na, K, Te, Se, Ge, Al, and Ga, or a substance that is decomposed to obtain the oxide of the element during the process of making the first main glass powder.

3. The high performance conductive silver aluminum paste according to claim 1, characterized in that: In the auxiliary glass powder, taking the total molar number of each component contained in the auxiliary glass powder as 100%, the molar percentage of each component is as follows: BaO 20.0%~40.0%; B2O3 5.0%~30.0%; SiO2 20.0%~50.0%; Li2O 12.0%~30.0%; Auxiliary modification additives 0.0%~20.0%; The auxiliary modifying additive is an oxide containing one or more elements of Pb, Bi, Al, Ga, K, Na, and Tl, or a substance that is decomposed to obtain the oxide of the element during the process of making the auxiliary glass powder.

4. The high performance conductive silver aluminum paste according to claim 1, characterized in that: The silver-aluminum paste additive is at least one of a silver-aluminum paste additive containing boron elements or a silver-aluminum paste additive containing zinc elements; the silver-aluminum paste additive containing boron elements is one or more of boron nitride, boron carbide, boron powder, aluminum boride, silicon boride, tungsten boride, and molybdenum boride; the silver-aluminum paste additive containing zinc elements is one or more of zinc powder, zinc oxide, zinc titanate, zinc stearate, and zinc palmitate.

5. The high performance conductive silver aluminum paste according to claim 1, characterized in that: The particle sizes of the silver powder, the aluminum powder, the glass powder and the silver-aluminum paste additive powder do not exceed 8 μm.

6. The high performance conductive silver aluminum paste according to claim 1, characterized in that: The organic carrier comprises an organic solvent, an organic resin and an additive. Taking the total weight of the organic carrier as 100%, the content of each component is as follows: Organic solvent 60.0%~80.0%; Organic resin 5.0%~25.0%; Additives 1.0%~25.0%.

7. A method for preparing the high-performance conductive silver-aluminum paste according to any one of claims 1 to 6, characterized in that: The process includes the following steps: Prepare the first main glass powder, the second main glass powder and the auxiliary glass powder: weigh the raw materials for the first main glass powder according to the set ratio, mix them, and then melt them at high temperature, cool them down and dry them, and then crush them to obtain the required first main glass powder; weigh the raw materials for the second main glass powder according to the set ratio, mix them, and then melt them at high temperature, cool them down and dry them, and then crush them to obtain the required second main glass powder; weigh the raw materials for the auxiliary glass powder according to the set ratio, mix them, and then melt them at high temperature, cool them down and dry them, and then crush them to obtain the required auxiliary glass powder. Preparation of organic carrier: weighing the raw materials used for the organic carrier according to a set ratio, heating and stirring to mix, high-speed centrifugation to disperse uniformly, and then filtering to obtain the organic carrier; Preparation of conductive silver-aluminum paste: silver powder, aluminum powder, glass powder, and silver-aluminum paste additives are added to the prepared organic carrier according to mass ratio, mixed and stirred evenly, and then ground, adjusted viscosity, and filtered to obtain the conductive silver-aluminum paste.

8. An electrode, characterized in that: The electrode is formed by sintering the high-performance conductive silver-aluminum paste described in any one of claims 1 to 6 on the surface of a battery silicon wafer.

9. A TOPcon battery, characterized in that: Comprising the electrode according to claim 8.

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