A high-conductivity main gate electrode silver paste and its preparation method and application

Abstract

The present application provides a highly conductive main grid electrode silver paste, its preparation method, and application, belonging to the field of solar cells. The main grid electrode silver paste is composed of the following components: 0.5 to 4 parts of a glass material, 50 to 70 parts of a silver conductive material, 10 to 30 parts of a silver alloy conductive material, 1 to 3 parts of an organic additive, 1 to 3 parts of a conductive polymer, and 10 to 15 parts of an organic carrier; the glass material is composed of a first glass material and a second glass material; the first glass material is a Bi-B-Zn-based lead-free low-temperature melting glass material; and the second glass material is a P-V-Zn-based lead-free low-temperature melting glass material. By rationally designing the chemical composition of the main grid electrode silver paste, the conductivity of the main grid electrode silver paste is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a high-conductivity main grid electrode silver paste and a preparation method and application thereof. Background Art

[0002] Busbar silver paste is a special conductive paste primarily used in the production of grid lines for photovoltaic cells. During the manufacturing process, busbar silver paste is applied to the front of the cell, forming a dense grid line structure that not only collects current but also supports and protects the cell.

[0003] Silver busbar paste is a key material responsible for collecting and transmitting current in photovoltaic cells. Its electrical conductivity directly impacts the efficiency of current transmission, and thus the photovoltaic cell's photoelectric conversion efficiency. With the continuous advancement of photovoltaic technology and the rapid development of the photovoltaic industry, the performance requirements for photovoltaic cells are becoming increasingly stringent. Existing busbar pastes lack the electrical conductivity required for high-performance photovoltaic cells, thus limiting their development and application. In particular, in fields requiring high-performance photovoltaic cells, such as aerospace and military, busbar pastes with poor electrical conductivity cannot meet these application requirements. Summary of the Invention

[0004] The present application provides a highly conductive main gate electrode silver paste and a preparation method and application thereof to solve the following technical problem: how to improve the conductivity of the main gate electrode silver paste.

[0005] In a first aspect, the present application provides a highly conductive main gate electrode silver paste, which is composed of the following components, calculated by mass: 0.5 to 4 parts of glass material, 50 to 70 parts of silver conductive material, 10 to 30 parts of silver alloy conductive material, 1 to 3 parts of organic additive, 1 to 3 parts of conductive polymer, and 10 to 15 parts of organic vehicle; wherein,

[0006] The glass material consists of a first glass material and a second glass material;

[0007] The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material;

[0008] The second glass material is a PV-Zn series lead-free low-temperature melting glass material.

[0009] Optionally, the mass ratio of the Bi-B-Zn series lead-free low-temperature melting glass material to the PV-Zn series lead-free low-temperature melting glass material is (2-4):1.

[0010] Optionally, the Bi-B-Zn lead-free low-temperature melting glass material is composed of the following components, in molar percentage: Bi2O3: 20-30 mol.%, B2O3: 40-50 mol.%, ZnO: 2-6 mol.%, SiO2: 2-6 mol.%, Al2O3: 1-5 mol.%, NaBr: 1-5 mol.%, SnO2: 1-5 mol.%, CdO: 1-5 mol.%.

[0011] Optionally, the PV-Zn-based lead-free low-temperature melting glass material is composed of the following components, in molar percentage: H3PO4: 40-50 mol.%, V2O5: 5-10 mol%, ZnO: 20-30 mol.%, In2O3: 5-10 mol%, KCl: 1-5 mol.%, CaO: 1-5 mol.%, Ce2O3: 1-5 mol.%, Y2O3: 1-5 mol.%.

[0012] Optionally, the silver alloy conductive material is composed of silver-clad nickel, silver-clad tungsten and silver-clad copper, and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is (1-5):(1-5):(1-5).

[0013] Optionally, the conductive polymer is composed of polyaniline, polypyrrole, polyethylene dioxythiophene, and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene, and the polystyrene sulfonic acid is 1:(1-2):(2-4):(2-4).

[0014] Optionally, the organic additives include at least one of the following: a dispersant, a thickener, a coupling agent, a surfactant, a leveling agent, and a defoaming agent; wherein,

[0015] The dispersant is polyvinyl pyrrolidone;

[0016] The thickener is ethyl cellulose or nitro cellulose;

[0017] The coupling agent is a silane coupling agent;

[0018] The surfactant is lecithin;

[0019] The leveling agent is dibutyl phthalate;

[0020] The defoaming agent is an organosilicon defoaming agent.

[0021] In a second aspect, the present application provides a method for preparing the highly conductive main gate electrode silver paste according to any embodiment of the first aspect, the method comprising the following steps:

[0022] S1, melting a first glass material and a second glass material to form a first glass liquid and a second glass liquid respectively;

[0023] S2, drying the first glass liquid and the second glass liquid respectively, and then processing them into a first glass material and a second glass material by using a jet mill process;

[0024] S3, mixing the first glass material and the second glass material to obtain a glass material;

[0025] S4, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend;

[0026] S5. The blend is subjected to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

[0027] Optionally, the microwave-ultrasound combined treatment includes the following parameters: microwave power is 100-200W, ultrasonic power is 200-300W, and treatment time is 10s-40s.

[0028] In a third aspect, the present application provides a battery, wherein the front paste used in the battery includes the highly conductive main grid electrode silver paste described in any one embodiment of the first aspect.

[0029] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0030] The embodiments of the present application provide a highly conductive main grid electrode silver paste. By rationally designing the chemical composition of the main grid electrode silver paste, the [BiO3], [BiO6], [BO3], and [BO4] units in the Bi-B-Zn glass interact with the [PO4], [VO2], and [VO3] groups in the PV-Zn glass. The [BiO3] and [BiO6] units can form cross-links with the [PO4] groups through oxygen atoms, enhancing the stability and strength of the network structure. The conductive polymer in the silver paste enhances the electrical conductivity and bonding strength. At the same time, it can form a good interface with the silver particles, improving the stability and reliability of the conductive network. The silver conductive material is the main conductive component in the silver paste and has good electrical conductivity and stability. The silver alloy conductive material in the silver paste plays a role in assisting electrical conduction and enhancing performance. This improves the conductivity of the main grid electrode silver paste. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 A schematic flow chart of a method for preparing a highly conductive main gate electrode silver paste provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0036] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this disclosure as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0037] In the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0039] In a first aspect, the present application provides a highly conductive main gate electrode silver paste, which is composed of the following components, calculated by mass: 0.5 to 4 parts of glass material, 50 to 70 parts of silver conductive material, 10 to 30 parts of silver alloy conductive material, 1 to 3 parts of organic additive, 1 to 3 parts of conductive polymer, and 10 to 15 parts of organic vehicle; wherein,

[0040] The glass material consists of a first glass material and a second glass material;

[0041] The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material;

[0042] The second glass material is a PV-Zn series lead-free low-temperature melting glass material.

[0043] The first glass material (a Bi-B-Zn-based lead-free, low-melting glass) has a low glass transition temperature, facilitating low-temperature sintering. Furthermore, the Bi-B-Zn-based glass exhibits excellent glass-forming properties and stability. Acting as a sintering aid, the first glass material facilitates the bonding of silver particles, improving the density and mechanical strength of the conductive layer. Furthermore, its low-temperature sintering properties minimize thermal damage to the substrate.

[0044] The second glass material (a lead-free, low-melting PV-Zn glass) also has a low glass transition temperature, excellent thermal stability, and the ability to maintain an amorphous state. Similar to Bi-B-Zn glass, the second glass material acts as a sintering aid to enhance the performance of the conductive layer. Furthermore, the addition of PV-Zn glass further optimizes the sintering characteristics and conductivity of the silver paste.

[0045] Silver conductive material is the main conductive component in silver paste. It has good conductivity and stability and can effectively transmit current. In silver paste, the content and particle size distribution of silver conductive material have a significant impact on the conductive performance.

[0046] Silver alloy conductive materials play a role in assisting conductivity and enhancing performance in silver paste. By adding an appropriate amount of silver alloy conductive materials, the conductivity and heat resistance of the silver paste can be further improved while reducing costs.

[0047] Conductive polymers enhance the conductivity and bonding strength of silver pastes. They form a good interface with silver particles, improving the stability and reliability of the conductive network.

[0048] Organic additives play a major role in dispersing, wetting, and stabilizing silver pastes. They improve the dispersion and fluidity of the silver paste, making the silver particles more evenly distributed on the substrate, thereby enhancing conductivity.

[0049] Organic vehicles, including polymer resins and organic solvents, can adjust the viscosity and fluidity of the silver paste to ensure that the silver paste maintains appropriate properties during the printing process. At the same time, the polymer resin is also responsible for fixing the silver particles on the substrate.

[0050] In some embodiments, the mass ratio of the Bi-B-Zn based lead-free low-temperature melting glass material to the PV-Zn based lead-free low-temperature melting glass material is (2-4):1.

[0051] Both Bi-B-Zn and PV-Zn lead-free low-temperature melting glass materials have relatively low glass transition temperatures. This allows the silver paste to be sintered at lower temperatures, promoting close bonding between silver particles and improving the density and conductivity of the conductive layer, thereby reducing thermal damage to the substrate.

[0052] The [BiO3], [BiO6], [BO3], and [BO4] units in Bi-B-Zn glass interact with the [PO4], [VO2], and [VO3] groups in PV-Zn glass. The [BiO3] and [BiO6] units can form cross-links with the [PO4] groups through oxygen atoms, enhancing the stability and strength of the network structure. Furthermore, the [BO3] and [BO4] units can interact with the [VO2] and [VO3] groups, further enriching the diversity of the network structure.

[0053] In addition, the two glass materials act as sintering aids to promote the sintering process between silver particles. During the sintering process, the glass materials melt and penetrate between the silver particles, forming a continuous glass phase, thereby strengthening the bonding force between the silver particles.

[0054] In some embodiments, the Bi-B-Zn based lead-free low-temperature melting glass material is composed of the following components, in molar percentage: Bi2O3: 20-30 mol.%, B2O3: 40-50 mol.%, ZnO: 2-6 mol.%, SiO2: 2-6 mol.%, Al2O3: 1-5 mol.%, NaBr: 1-5 mol.%, SnO2: 1-5 mol.%, CdO: 1-5 mol.%.

[0055] Bi2O3: Its primary function is to lower the melting temperature of glass, forming structural units such as [BiO3] and [BiO6]. Changes in these unit structures affect the glass network structure, thereby affecting its performance. While an appropriate amount of Bi2O3 helps form a stable glass structure and provides a good carrier for silver paste, an excessive amount can loosen the glass structure and affect conductivity.

[0056] B2O3: One of the primary oxides in glass formation, it forms [BO3] and [BO4] structural units. It improves the transparency and gloss of glass and enhances the conductivity of silver paste. It also interacts with Bi2O3 to influence the network structure and properties of glass.

[0057] ZnO: It has little effect on the glass structure, but can improve the transparency and chemical stability of the glass. In silver paste, ZnO can act as a flux, helping the sintering of silver particles and the formation of a conductive network.

[0058] SiO2: It is an important component in glass formation, which can increase the hardness and chemical stability of glass. In silver paste, an appropriate amount of SiO2 helps to form a dense conductive network and improve conductivity.

[0059] Al2O3: It can improve the chemical stability and mechanical strength of glass. In silver paste, Al2O3 can act as a reinforcing agent, helping to form a stable conductive network.

[0060] NaBr: As a halide additive, it can lower the melting point of glass while improving its transparency and gloss. In silver paste, NaBr can help sinter silver particles and optimize the conductive network.

[0061] SnO2: A conductive oxide that forms a good interface with silver particles, improving the conductivity of the silver paste. In glass, SnO2 can also increase the refractive index and gloss of the glass.

[0062] CdO: It is a conductive oxide that can increase the refractive index and solubility of glass. In silver paste, CdO can play a similar role in enhancing conductivity.

[0063] In some embodiments, the PV-Zn-based lead-free low-temperature melting glass material is composed of the following components, in molar percentage: H3PO4: 40-50 mol.%, V2O5: 5-10 mol%, ZnO: 20-30 mol.%, In2O3: 5-10 mol%, KCl: 1-5 mol.%, CaO: 1-5 mol.%, Ce2O3: 1-5 mol.%, Y2O3: 1-5 mol.%.

[0064] H3PO4: H3PO4 decomposes into P2O5 at high temperatures. P2O5 forms a glass network structure with V2O5 and ZnO, affecting the melting point and stability of the glass. The phosphate structure can indirectly affect the conductivity of the silver paste by affecting the internal structure of the glass.

[0065] V2O5: V2O5 forms a chain-like vanadate structure within the glass network, reducing the degree of cross-linking. An appropriate amount of V2O5 can lower the melting point of glass, helping silver paste sinter at low temperatures and forming a good conductive path.

[0066] ZnO: ZnO is a modifier in the glass network structure, altering its structure and properties. While variations in ZnO content have minimal impact on the glass structure, an appropriate amount of ZnO can help lower the melting point and improve stability. In silver pastes, ZnO provides excellent ionic conductivity, enhancing the paste's electrical conductivity.

[0067] In2O3: In2O3 is a wide bandgap semiconductor material with good electron mobility and chemical stability. In silver paste, In2O3 can be used as a dopant to improve the conductivity and stability of the silver paste.

[0068] KCl: KCl melts at high temperatures to form a molten salt with good ionic conductivity. In silver paste, KCl can act as an electrolyte, promoting ion migration and bonding between silver particles, thereby improving the conductive properties of the silver paste.

[0069] CaO, Ce2O3, and Y2O3: These oxides act as network modifiers in glass, altering its structure and properties. They also act as stabilizers, improving the chemical and thermal stability of glass. Furthermore, in silver pastes, these oxides can indirectly affect the conductivity of the silver paste by influencing the structure and properties of the glass.

[0070] In some embodiments, the silver alloy conductive material is composed of silver-clad nickel, silver-clad tungsten and silver-clad copper, and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is (1-5):(1-5):(1-5).

[0071] Silver-clad nickel is a composite material with a silver shell and a nickel core. The addition of nickel significantly improves the material's hardness and wear resistance while maintaining the conductive properties of silver. Nickel also exhibits excellent corrosion and oxidation resistance, helping to improve the stability of silver alloy conductive materials in harsh environments.

[0072] Silver-coated tungsten is a composite material with a silver shell and a tungsten core. Tungsten has an extremely high melting point and exhibits excellent thermal stability and mechanical strength. Among silver alloy conductive materials, silver-coated tungsten enhances overall thermal stability and mechanical strength while maintaining excellent electrical conductivity.

[0073] Silver-clad copper is a composite material with a silver outer shell and a copper core. Copper's electrical conductivity is second only to silver, and its cost is relatively low. The addition of silver-clad copper effectively reduces the cost of silver alloy conductive materials while maintaining high electrical conductivity.

[0074] The mass ratio of silver-coated nickel, silver-coated tungsten, and silver-coated copper is limited to (1-5):(1-5):(1-5). Silver-coated nickel, silver-coated tungsten, and silver-coated copper can complement each other to form a more stable and efficient conductive network. At the same time, silver-coated nickel, silver-coated tungsten, and silver-coated copper can work together to improve the mechanical properties of the material, forming a comprehensive performance of high strength, high hardness, and high toughness. In addition, silver-coated nickel, silver-coated tungsten, and silver-coated copper can work together to improve the thermal stability of the material, enabling it to maintain stable performance at high temperatures.

[0075] In some embodiments, the conductive polymer is composed of polyaniline, polypyrrole, polyethylene dioxythiophene, and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene, and the polystyrene sulfonic acid is 1:(1-2):(2-4):(2-4).

[0076] Conductive polymers are a new class of materials with excellent electrical conductivity and processing properties. They are typically composed of polymer chains with large π-bond conjugated structures. The delocalized π electrons within these polymer chains can move freely along the chains, imparting electrical conductivity. Adding conductive polymers to conductive silver pastes can significantly enhance conductivity, forming a more efficient conductive network.

[0077] First, the molecular chains of polyaniline, polypyrrole, and PEDOT all contain aromatic ring structures, which can attract each other through π-π stacking, forming a stable intermolecular structure. This stacking effect helps strengthen the interaction between the molecular chains and improve the overall stability of the material. Second, the amino groups on the polyaniline and polypyrrole molecular chains and the nitrogen atoms on the pyrrole ring can form hydrogen bonds with sulfonic acid groups, hydroxyl groups, and other groups in other components. The formation of hydrogen bonds can further enhance the interaction between the molecular chains and improve the mechanical strength and heat resistance of the material. Third, the sulfonic acid groups on the polystyrene sulfonic acid molecular chains are negatively charged, which can form electrostatic interactions with positively charged regions (such as incompletely doped nitrogen atoms) on the polyaniline, polypyrrole, and PEDOT molecular chains. This electrostatic interaction helps stabilize the molecular structure and can affect the material's conductive properties.

[0078] In some embodiments, the organic additive includes at least one of the following: a dispersant, a thickener, a coupling agent, a surfactant, a leveling agent, and a defoaming agent; wherein,

[0079] The dispersant is polyvinyl pyrrolidone;

[0080] The thickener is ethyl cellulose or nitro cellulose;

[0081] The coupling agent is a silane coupling agent;

[0082] The surfactant is lecithin;

[0083] The leveling agent is dibutyl phthalate;

[0084] The defoaming agent is an organosilicon defoaming agent.

[0085] Polyvinylpyrrolidone interacts with the particle surface through the hydrophilic groups in its molecular structure, forming an adsorption film that alters the hydrophilic and lipophilic properties of the particle surface. This adsorption film envelops the particles, creating repulsive forces between them, effectively preventing aggregation and precipitation, and achieving uniform particle dispersion. PVP dispersants also form a dense protective film on the particle surface, enhancing particle stability and extending the stability of the dispersion. Furthermore, PVP dispersants exhibit surface activity, reducing interparticle surface tension and promoting dispersion and stability of the particles in the solvent.

[0086] Both ethyl cellulose and nitrocellulose thicken by forming hydrogen bonds with water molecules. When added to water, their molecular chains form hydrogen bonds with the water molecules, forming a gel structure that can fix the position of the water molecules, thereby increasing the viscosity and consistency of the solution.

[0087] Silane coupling agents contain functional groups in their molecular structure that can react chemically with both inorganic and organic materials. Silane coupling agents form strong chemical bonds between inorganic and organic materials, significantly improving the properties of composite materials.

[0088] Figure 1 A schematic flow chart of a method for preparing a highly conductive main gate electrode silver paste provided in an embodiment of the present application.

[0089] like Figure 1 As shown, the present application provides a method for preparing a high-conductivity main gate electrode silver paste according to any embodiment of the first aspect, the method comprising the following steps:

[0090] S1, melting a first glass material and a second glass material to form a first glass liquid and a second glass liquid respectively;

[0091] S2, drying the first glass liquid and the second glass liquid respectively, and then processing them into a first glass material and a second glass material by using a jet mill process;

[0092] Jet milling is an efficient pulverization method that can ensure that the particle size of glass powder is uniform and fine.

[0093] S3, mixing the first glass material and the second glass material to obtain a glass material;

[0094] S4, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend;

[0095] S5. The blend is subjected to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

[0096] In some embodiments, the microwave-ultrasound combined treatment includes the following parameters: microwave power of 100-200 W, ultrasonic power of 200-300 W, and treatment time of 10 s to 40 s.

[0097] During the preparation process, silver particles and glass powder in silver paste can form agglomerates, which can affect the dispersion and conductivity of the silver paste. Microwave-ultrasound combined treatment generates strong vibrations and impacts, effectively breaking up these agglomerates and dispersing the silver particles and glass powder more evenly in the organic vehicle.

[0098] The penetrating and heating properties of microwaves rapidly heat the blend, accelerating thermal motion between molecules and promoting the dispersion of silver particles and glass powder in the organic carrier. Simultaneously, the cavitation and microfluidization effects of ultrasound create a strong stirring effect at the microscopic scale, further promoting mixing and uniform distribution of the components.

[0099] Microwave-ultrasonic combined treatment not only promotes physical dispersion but also triggers or accelerates certain chemical reactions, such as oxidation and reduction reactions on the surface of silver particles, and the interaction between glass powder and silver particles. These reactions help enhance the internal structure and properties of the silver paste, such as improving electrical conductivity and corrosion resistance.

[0100] Microwave-ultrasonic combined treatment can make silver particles more closely packed together, forming more conductive channels, thereby improving the conductivity of the silver paste. At the same time, microstructural changes produced during the treatment process also help improve conductivity, such as increasing the contact area between silver particles and reducing contact resistance.

[0101] Microwave-ultrasonic combined treatment can improve the coating properties of silver paste, making it easier to apply evenly to the substrate. This helps to improve the adhesion and coverage of the silver paste to the substrate, thereby further improving the performance and reliability of the device.

[0102] Based on a general inventive concept, the present application provides a battery, wherein the front paste used in the battery includes the high-conductivity main grid electrode silver paste described in any one embodiment of the first aspect.

[0103] In summary, the main gate electrode silver paste and preparation method of the present application have the following significant advantages:

[0104] (1) Optimized glass material combination: By using two lead-free, low-temperature melting glass materials, Bi-B-Zn and PV-Zn, low-temperature sintering characteristics are achieved, which helps reduce thermal damage to the substrate. At the same time, the interaction between the two glass materials enhances the stability and strength of the network structure, further optimizing the sintering characteristics and conductive properties of the silver paste.

[0105] (2) Efficient conductive material ratio: The rational combination of silver conductive material and silver alloy conductive material not only improves the conductivity and heat resistance of silver paste, but also effectively reduces costs. At the same time, the composite use of silver-coated nickel, silver-coated tungsten and silver-coated copper forms a more stable and efficient conductive network, improving the overall performance of the material.

[0106] (3) Innovative conductive polymer addition: The addition of conductive polymer significantly enhances the conductivity of the silver paste, forming a more efficient conductive network. The synergistic effect of conductive polymers such as polyaniline, polypyrrole, polyethylenedioxythiophene, and polystyrene sulfonic acid improves the stability and heat resistance of the material.

[0107] (4) Complete organic additive system: The rational selection of organic additives such as dispersants, thickeners, coupling agents, surfactants, leveling agents and defoamers improves the dispersion, fluidity and stability of the silver paste. These additives help to evenly distribute the silver particles on the substrate and improve the conductive properties.

[0108] (5) Advanced microwave-ultrasound combined treatment technology: Microwave-ultrasound combined treatment can effectively destroy the agglomerated structure of silver particles and glass powder, making them more evenly dispersed in the organic carrier. This technology promotes mixing and uniform distribution between the components, improving the conductivity and corrosion resistance of the silver paste. At the same time, the synergistic effect of microwaves and ultrasound also triggers or accelerates certain chemical reactions, enhancing the internal structure and performance of the silver paste.

[0109] (6) Precise control of the preparation process: The conditions and parameters of each step are strictly controlled during the preparation process, such as the melting, drying and crushing of the glass material, and the microwave-ultrasonic combined treatment of the blend. These precise controls ensure the stability and consistency of the quality and performance of the silver paste.

[0110] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are generally measured according to industry standards. If there are no corresponding industry standards, then the methods are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0111] Example 1

[0112] This embodiment provides a high-conductivity main gate electrode silver paste, which is composed of the following components, calculated by mass: 2.5 parts of glass material, 60 parts of silver conductive material, 20 parts of silver alloy conductive material, 2 parts of organic additive, 2 parts of conductive polymer, and 13.5 parts of organic vehicle; wherein,

[0113] The glass material consists of a first glass material and a second glass material;

[0114] The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material;

[0115] The second glass material is a PV-Zn series lead-free low-temperature melting glass material.

[0116] The mass ratio of the Bi-B-Zn series lead-free low-temperature melting glass material to the PV-Zn series lead-free low-temperature melting glass material is 3:1.

[0117] In terms of molar percentage, the Bi-B-Zn lead-free low-temperature melting glass material consists of the following components: Bi2O3: 30 mol.%, B2O3: 50 mol.%, ZnO: 4 mol.%, SiO2: 4 mol.%, Al2O3: 3 mol.%, NaBr: 3 mol.%, SnO2: 3 mol.%, CdO: 3 mol.%.

[0118] In terms of molar percentage, the PV-Zn series lead-free low-temperature melting glass material consists of the following components: H3PO4: 47 mol.%, V2O5: 9 mol.%, ZnO: 26 mol.%, In2O3: 8 mol.%, KCl: 3 mol.%, CaO: 2 mol.%, Ce2O3: 2 mol.%, Y2O3: 3 mol.%.

[0119] The silver alloy conductive material is composed of silver-clad nickel (YF-NI420), silver-clad tungsten (AgW50) and silver-clad copper (YF-A625), and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is 2:3:4.

[0120] The conductive polymer consists of polyaniline, polypyrrole, polyethylene dioxythiophene, and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene, and the polystyrene sulfonic acid is 1:1:3:3.

[0121] The organic auxiliary agent is a dispersant, and the dispersant is polyvinyl pyrrolidone (model PVPK17).

[0122] The organic carrier consists of an organic resin and an organic solvent, the mass ratio of the organic resin content to the organic solvent is 30:70, the organic solvent is diethylene glycol butyl ether acetate, and the organic resin is ethyl cellulose resin.

[0123] Based on the above-mentioned high-conductivity main gate electrode silver paste, this embodiment also provides a method for preparing a high-conductivity main gate electrode silver paste, the method comprising the following steps:

[0124] S11, uniformly mixing the first glass material and the second glass material in a mixer, heating the mixture in a high-temperature furnace, and melting the mixture at high temperature to form uniform glass liquid, thereby forming a first glass liquid and a second glass liquid respectively;

[0125] S21, extracting the first glass liquid and the second glass liquid separately, cooling and drying the dried glass material, crushing the dried glass material, and polishing, grinding and grading the crushed glass material using a jet mill to obtain a first glass material and a second glass material;

[0126] S31, mixing the first glass material and the second glass material to obtain a glass material;

[0127] S41, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend;

[0128] S51, subjecting the blend to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

[0129] The microwave-ultrasound combined treatment includes the following parameters: microwave power is 150W, ultrasonic power is 250W, and treatment time is 20s.

[0130] Example 2

[0131] This embodiment provides a high-conductivity main gate electrode silver paste, which is composed of the following components, calculated by mass: 4 parts of glass material, 50 parts of silver conductive material, 30 parts of silver alloy conductive material, 3 parts of organic additive, 3 parts of conductive polymer, and 10 parts of organic vehicle; wherein,

[0132] The glass material consists of a first glass material and a second glass material;

[0133] The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material;

[0134] The second glass material is a PV-Zn series lead-free low-temperature melting glass material.

[0135] The mass ratio of the Bi-B-Zn series lead-free low-temperature melting glass material to the PV-Zn series lead-free low-temperature melting glass material is 2:1.

[0136] In terms of molar percentage, the Bi-B-Zn lead-free low-temperature melting glass material consists of the following components: Bi2O3: 20 mol.%, B2O3: 50 mol.%, ZnO: 5 mol.%, SiO2: 5 mol.%, Al2O3: 5 mol.%, NaBr: 5 mol.%, SnO2: 5 mol.%, CdO: 5 mol.%.

[0137] In terms of molar percentage, the PV-Zn series lead-free low-temperature melting glass material consists of the following components: H3PO4: 40 mol.%, V2O5: 10 mol.%, ZnO: 30 mol.%, In2O3: 10 mol.%, KCl: 4 mol.%, CaO: 1 mol.%, Ce2O3: 1 mol.%, Y2O3: 4 mol.%.

[0138] The silver alloy conductive material consists of silver-clad nickel, silver-clad tungsten and silver-clad copper, and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is 5:3:1.

[0139] The conductive polymer consists of polyaniline, polypyrrole, polyethylene dioxythiophene, and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene, and the polystyrene sulfonic acid is 1:2:2:2.

[0140] The organic additives are a dispersant and a coupling agent, the mass ratio of the dispersant to the coupling agent is 1:1, the dispersant is polyvinyl pyrrolidone (model PVPK17), and the coupling agent is KH550.

[0141] The organic carrier consists of an organic resin and an organic solvent, the mass ratio of the organic resin content to the organic solvent is 25:75, the organic solvent is diethylene glycol butyl ether acetate, and the organic resin is ethyl cellulose resin.

[0142] Based on the above-mentioned high-conductivity main gate electrode silver paste, this embodiment also provides a method for preparing a high-conductivity main gate electrode silver paste, the method comprising the following steps:

[0143] S11, uniformly mixing the first glass material and the second glass material in a mixer, heating the mixture in a high-temperature furnace, and melting the mixture at high temperature to form uniform glass liquid, thereby forming a first glass liquid and a second glass liquid respectively;

[0144] S21, extracting the first glass liquid and the second glass liquid separately, cooling and drying the dried glass material, crushing the dried glass material, and polishing, grinding and grading the crushed glass material using a jet mill to obtain a first glass material and a second glass material;

[0145] S31, mixing the first glass material and the second glass material to obtain a glass material;

[0146] S41, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend;

[0147] S51, subjecting the blend to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

[0148] The microwave-ultrasound combined treatment includes the following parameters: microwave power is 200W, ultrasonic power is 300W, and treatment time is 10s.

[0149] Example 3

[0150] This embodiment provides a high-conductivity main gate electrode silver paste, which is composed of the following components by mass: 1 part of glass material, 70 parts of silver conductive material, 10 parts of silver alloy conductive material, 2 parts of organic additive, 2 parts of conductive polymer, and 15 parts of organic vehicle; wherein,

[0151] The glass material consists of a first glass material and a second glass material;

[0152] The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material;

[0153] The second glass material is a PV-Zn series lead-free low-temperature melting glass material.

[0154] The mass ratio of the Bi-B-Zn series lead-free low-temperature melting glass material to the PV-Zn series lead-free low-temperature melting glass material is 4:1.

[0155] In terms of molar percentage, the Bi-B-Zn lead-free low-temperature melting glass material consists of the following components: Bi2O3: 30 mol.%, B2O3: 40 mol.%, ZnO: 6 mol.%, SiO2: 4 mol.%, Al2O3: 5 mol.%, NaBr: 5 mol.%, SnO2: 5 mol.%, CdO: 5 mol.%.

[0156] In terms of molar percentage, the PV-Zn series lead-free low-temperature melting glass material consists of the following components: H3PO4: 40 mol.%, V2O5: 10 mol.%, ZnO: 30 mol.%, In2O3: 5 mol.%, KCl: 5 mol.%, CaO: 2 mol.%, Ce2O3: 3 mol.%, Y2O3: 5 mol.%.

[0157] The silver alloy conductive material consists of silver-clad nickel, silver-clad tungsten and silver-clad copper, and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is 1:3:5.

[0158] The conductive polymer consists of polyaniline, polypyrrole, polyethylene dioxythiophene and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene and the polystyrene sulfonic acid is 1:2:4:4.

[0159] The organic auxiliary agent is a dispersant, and the dispersant is polyvinyl pyrrolidone (model PVPK17).

[0160] The organic carrier consists of an organic resin and an organic solvent, the mass ratio of the organic resin content to the organic solvent is 35:65, and the organic solvent is diethylene glycol butyl ether acetate.

[0161] Based on the above-mentioned high-conductivity main gate electrode silver paste, this embodiment also provides a method for preparing a high-conductivity main gate electrode silver paste, the method comprising the following steps:

[0162] S11, uniformly mixing the first glass material and the second glass material in a mixer, heating the mixture in a high-temperature furnace, and melting the mixture at high temperature to form uniform glass liquid, thereby forming a first glass liquid and a second glass liquid respectively;

[0163] S21, extracting the first glass liquid and the second glass liquid separately, cooling and drying the dried glass material, crushing the dried glass material, and polishing, grinding and grading the crushed glass material using a jet mill to obtain a first glass material and a second glass material;

[0164] S31, mixing the first glass material and the second glass material to obtain a glass material;

[0165] S41, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend;

[0166] S51, subjecting the blend to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

[0167] The microwave-ultrasound combined treatment includes the following parameters: microwave power is 100W, ultrasonic power is 200W, and treatment time is 40s.

[0168] Comparative Example 1

[0169] This comparative example is modified as follows based on Example 1:

[0170] The main grid electrode silver paste is composed of the following components in parts by mass: 2.5 parts of glass material, 80 parts of silver conductive material, 2 parts of organic additive, 2 parts of conductive polymer, and 13.5 parts of organic vehicle.

[0171] Comparative Example 2

[0172] This comparative example is modified as follows based on Example 1:

[0173] No conductive polymer is added to the main gate electrode silver paste.

[0174] Comparative Example 3

[0175] This comparative example is modified as follows based on Example 1:

[0176] The glass material is only the first glass material.

[0177] Comparative Example 4

[0178] This comparative example is modified as follows based on Example 1:

[0179] The glass material is only the second glass material.

[0180] Comparative Example 5

[0181] This comparative example is modified as follows based on Example 1:

[0182] In step S51, the microwave-ultrasound combined treatment is not performed.

[0183] The present invention tests the performance of the main gate electrode silver paste prepared in Examples 1 to 3 and Comparative Examples 1 to 5. The specific testing method is as follows. The test results are shown in Table 1.

[0184] Viscosity: The viscosity of the slurry was tested using a Mars40 dynamic shear rheometer in DV2T mode with a temperature control of 25°C.

[0185] Resistivity after curing: Print a fixed pattern on the test piece, measure the resistance value after curing (0.6 × 60 mm), and calculate the resistivity according to the formula R = ρ·L / S;

[0186] Welding tensile strength: Use 0.35mm tin-coated solder ribbon to weld the front and back main grid electrodes of the battery at 360℃, and use a tensile testing machine to perform tensile testing.

[0187] Table 1 Performance of main grid electrode silver paste

[0188]

[0189] As shown in Table 1, the viscosity of the main gate electrode silver paste of Examples 1 to 3 is 175 to 185 Pa˙s, and the conductivity is 8.0 to 8.5×10 -6 Ωcm, welding tension is 2.5~3.0N / mm.

[0190] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A highly conductive main gate electrode silver paste, characterized in that: The main gate electrode silver paste is composed of the following components in parts by mass: 0.5 to 4 parts of glass material, 50 to 70 parts of silver conductive material, 10 to 30 parts of silver alloy conductive material, 1 to 3 parts of organic additive, 1 to 3 parts of conductive polymer, and 10 to 15 parts of organic vehicle; wherein, The glass material consists of a first glass material and a second glass material; The first glass material is a Bi-B-Zn series lead-free low-temperature melting glass material; The second glass material is a PV-Zn series lead-free low-temperature melting glass material; Wherein, the mass ratio of the Bi-B-Zn series lead-free low-temperature melting glass material to the PV-Zn series lead-free low-temperature melting glass material is (2-4):1; In terms of molar percentage, the Bi-B-Zn lead-free low-temperature melting glass material is composed of the following components: Bi2O3: 20-30 mol.%, B2O3: 40-50 mol.%, ZnO: 2-6 mol.%, SiO2: 2-6 mol.%, Al2O3: 1-5 mol.%, NaBr: 1-5 mol.%, SnO2: 1-5 mol.%, CdO: 1-5 mol.%; In terms of molar percentage, the PV-Zn series lead-free low-temperature melting glass material is composed of the following components: H3PO4: 40-50 mol.%, V2O5: 5-10 mol%, ZnO: 20-30 mol.%, In2O3: 5-10 mol%, KCl: 1-5 mol.%, CaO: 1-5 mol.%, Ce2O3: 1-5 mol.%, Y2O3: 1-5 mol.%; The method for preparing the main gate electrode silver paste comprises the following steps: S1, melting a first glass material and a second glass material to form a first glass liquid and a second glass liquid respectively; S2, drying the first glass liquid and the second glass liquid respectively, and then processing them into a first glass material and a second glass material by using a jet mill process; S3, mixing the first glass material and the second glass material to obtain a glass material; S4, mixing the glass material, the silver conductive material, the silver alloy conductive material, the organic additive and the organic carrier to obtain a blend; S5. The blend is subjected to a microwave-ultrasound combined treatment to obtain the main gate electrode silver paste.

2. The high-conductivity main gate electrode silver paste according to claim 1, characterized in that: The silver alloy conductive material consists of silver-clad nickel, silver-clad tungsten and silver-clad copper, and the mass ratio of the silver-clad nickel, the silver-clad tungsten and the silver-clad copper is (1-5):(1-5):(1-5).

3. The high-conductivity main gate electrode silver paste according to claim 1, characterized in that: The conductive polymer consists of polyaniline, polypyrrole, polyethylene dioxythiophene and polystyrene sulfonic acid, and the mass ratio of the polyaniline, the polypyrrole, the polyethylene dioxythiophene and the polystyrene sulfonic acid is 1:(1-2):(2-4):(2-4).

4. The high-conductivity main gate electrode silver paste according to claim 1, characterized in that: The organic additives include at least one of the following: dispersant, thickener, coupling agent, surfactant, leveling agent and defoamer; wherein, The dispersant is polyvinyl pyrrolidone; The thickener is ethyl cellulose or nitro cellulose; The coupling agent is a silane coupling agent; The surfactant is lecithin; The leveling agent is dibutyl phthalate; The defoaming agent is an organosilicon defoaming agent.

5. The high-conductivity main gate electrode silver paste according to claim 1, characterized in that: The microwave-ultrasound combined treatment includes the following parameters: microwave power is 100-200W, ultrasonic power is 200-300W, and treatment time is 10s-40s.

6. A battery, characterized in that: The front paste used in the battery includes the high-conductivity main grid electrode silver paste according to any one of claims 1 to 5.

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