A kind of photovoltaic cell main grid electrode base metal paste and its preparation method, photovoltaic cell main grid electrode, photovoltaic cell and photovoltaic system

Abstract

The application provides a kind of photovoltaic cell main grid electrode base metal paste and its preparation method, photovoltaic cell main grid electrode, photovoltaic cell and photovoltaic system, relate to the field of photovoltaic cell.In the paste, by its own mass 100%, including organic carrier 5-20%, silver powder 75-85%, glass powder 1-1.2%, silver copper alloy powder 5-20%.After reasonable formula design and process optimization, photovoltaic cell main grid electrode base metal paste can ensure good conductivity at the same time, meet the requirements of current collection and transmission of photovoltaic cell electrode, so as to ensure that photovoltaic cell has higher photoelectric conversion efficiency and power output.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cells, and in particular to a base metal paste for a photovoltaic cell main grid electrode and its preparation method, a photovoltaic cell main grid electrode, a photovoltaic cell, and a photovoltaic system. Background Technology

[0002] Common photovoltaic (PV) cell busbar paste mainly consists of silver powder, a glass system (glass powder), and an organic carrier. Busbar silver paste has excellent conductivity, effectively collecting the current generated inside the cell and transmitting it to the external circuit, which is fundamental for the normal operation of PV cells. The busbar silver paste adheres firmly to the surface of the PV cell, forming a stable grid structure, which is crucial for the long-term stable operation of the cell. However, silver, as a precious metal, is relatively expensive, thus the cost of busbar silver paste is also high. Furthermore, silver is a finite natural resource, and its mining and refining processes may have certain environmental impacts. Therefore, on the one hand, silver is a finite natural resource, and its mining and refining processes may have certain environmental impacts; on the other hand, with the rapid development of the photovoltaic industry, the demand for silver is constantly increasing, which may lead to the depletion of silver resources and rising prices.

[0003] Base metals are a relative concept, generally referring to those abundant, relatively inexpensive, and common base metals such as iron, copper, aluminum, lead, zinc, and tin. Therefore, how to leverage the cost and abundance advantages of base metals to further reduce the overall manufacturing cost of photovoltaic modules while ensuring the conductivity and compatibility of the photovoltaic cell's main grid electrode, thereby enhancing the competitiveness of the photovoltaic industry and promoting its large-scale application and widespread adoption, has become an urgent technical problem to be solved. Summary of the Invention

[0004] The purpose of this application is to provide a base metal paste for a photovoltaic cell main grid electrode and its preparation method, a photovoltaic cell main grid electrode, a photovoltaic cell, and a photovoltaic system to solve the above-mentioned problems.

[0005] To achieve the above objectives, this application adopts the following technical solution: This application provides a base metal paste for the main grid electrode of a photovoltaic cell, which, based on its own weight of 100%, includes 5-20% organic carrier, 75-85% silver powder, 1-1.2% glass powder, and 5-20% silver-copper alloy powder.

[0006] Optionally, the organic carrier, by its own weight, comprises 60-70% organic solvent, 5-20% thickener, 10-30% thixotropic agent, 1-5% surfactant, 1-5% coupling agent, and 1-3% lubricant.

[0007] Optionally, the solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether acetate, dibutyl phthalate, butyl carbitol, and hexanediol.

[0008] Optionally, the thickener includes ethyl cellulose.

[0009] Optionally, the thixotropic agent includes at least one of hydrogenated castor oil and polyamide wax.

[0010] Optionally, the surfactant includes triethanolamine.

[0011] Optionally, the coupling agent includes the silane coupling agent KH570.

[0012] Optionally, the lubricant includes at least one of calcium stearate and glyceryl monostearate.

[0013] Optionally, the silver powder includes spherical silver powder and flake silver powder.

[0014] Optionally, the spherical silver powder has a particle size of D50 = 0.3-3.2 μm, and the flake silver powder has a particle size of 1.5-4 μm.

[0015] Optionally, the tap density of the silver powder is greater than 4.5 g / cm³. 3 .

[0016] Optionally, the mass ratio of the spherical silver powder with D50=0.3-0.7µm, the spherical silver powder with D50=0.45-0.85µm, the spherical silver powder with D50=2.12-2.52µm, the spherical silver powder with D50=2.74-3.14µm, and the flake-shaped silver powder with D50=1.5-4µm is 20%:30%:10%:10%:30%.

[0017] Optionally, the glass powder has a particle size D50 of 0.3-3 μm.

[0018] Optionally, the silver-copper alloy powder includes silver-copper binary alloy powder, silver-copper ternary alloy powder, and silver-copper quaternary alloy powder.

[0019] Optionally, the silver-copper alloy powder comprises 15% silver and 85% copper, based on 100% of its own mass.

[0020] Optionally, the particle size of the silver-copper alloy powder is 0.5-3.5 μm.

[0021] Optionally, the specific surface area of ​​the silver-copper alloy powder is 0.3-4 m². 2 / g.

[0022] This application also provides a method for preparing a base metal paste for the main busbar electrode of a photovoltaic cell, including: The organic carrier, silver powder, glass powder, and silver-copper alloy powder are mixed, dispersed, and ground to obtain a coarse slurry. The viscosity of the coarse slurry is adjusted to obtain the base metal slurry for the main grid electrode.

[0023] Optionally, the silver powder is prepared by chemical reduction.

[0024] Optionally, the silver-copper alloy powder is prepared by mechanical alloying and / or atomization.

[0025] Optionally, the method for preparing the glass powder includes mixing the component compounds and melting them at 1200°C for 30 minutes until the component compounds are completely liquefied, followed by quenching, grinding, initial sieving, evaporation, and re-sieving to obtain the glass powder; based on 100% of the glass powder itself, the component compounds include PbO2 10.0-45.0%, SiO2 10.0-45.0%, PbO 10.0-35.0%, TeO2 10.0-35.0%, TiO2 5.0-20.0%, B2O3 5.0-15.0%, Bi2O3 5.0-10.0%, and ZnO 2.5-10.0%.

[0026] This application also provides a photovoltaic cell main grid electrode, which is prepared from the photovoltaic cell main grid electrode base metal paste or the photovoltaic cell main grid electrode base metal paste prepared by the preparation method of the photovoltaic cell main grid electrode base metal paste.

[0027] This application also provides a photovoltaic cell, wherein the photovoltaic cell has a main grid electrode.

[0028] This application also provides a photovoltaic system, including the photovoltaic cell.

[0029] Compared with the prior art, the beneficial effects of this application include: The photovoltaic cell main grid electrode base metal paste provided in this application uses copper, which is much cheaper than silver. Using base metal paste can significantly reduce the cost of photovoltaic cell electrode materials, thereby reducing the overall manufacturing cost of photovoltaic modules, helping to improve the competitiveness of the photovoltaic industry, and promoting its large-scale application and popularization. Furthermore, copper's conductivity is second only to silver. With reasonable formula design and process optimization, the photovoltaic cell main grid electrode base metal paste can meet the requirements of photovoltaic cell electrodes for current collection and transmission while ensuring good conductivity, thereby ensuring that the photovoltaic cell has high photoelectric conversion efficiency and power output. The method for preparing base metal paste for photovoltaic cell main grid electrode provided in this application does not require large-scale equipment modification and process adjustment. It can easily replace precious metal paste in the production of photovoltaic cells, reducing technology conversion costs and production risks, and is conducive to the technological upgrading and process improvement of the photovoltaic industry.

[0030] The photovoltaic cell busbar electrode, photovoltaic cell, and photovoltaic system provided in this application have excellent electrical performance. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0032] Figure 1 The image shows the SEM spectra of the base metal slurry particles of the photovoltaic cell main grid electrode prepared in Example 1. Detailed Implementation

[0033] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0034] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0035] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0036] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0037] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0038] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0039] To better explain the technical solution provided in this application, the technical solution will be described in its entirety before the embodiments.

[0040] In a first aspect, this application provides a base metal paste for the main grid electrode of a photovoltaic cell, which, based on its own weight of 100%, includes 5-20% organic carrier, 75-85% silver powder, 1-1.2% glass powder, and 5-20% silver-copper alloy powder.

[0041] Optionally, based on the mass of the base metal paste of the photovoltaic cell's main grid electrode as 100%, the mass of the organic carrier can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between 10% and 20%; the mass of the silver powder can be 75%, 77%, 79%, 81%, 83%, 85%, or any value between 65% and 85%; the mass of the glass powder can be 1%, 1.05%, 1.1%, 1.15%, 1.2%, or any value between 1% and 1.2%; and the mass of the silver-copper alloy powder can be 15%, 16%, 17%, 18%, 19%, 20%, or any value between 15% and 20%.

[0042] In one optional embodiment, the organic carrier comprises, by weight, 60-70% organic solvent, 5-20% thickener, 10-30% thixotropic agent, 1-5% surfactant, 1-5% coupling agent, and 1-3% lubricant.

[0043] Optionally, the amount of organic carrier can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, or any value between 60% and 70%. The amount of thickener can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between 5% and 20%. The amount of thixotropic agent can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, or any value between 10% and 30%. The amount of surfactant can be 1%, 2%, 3%, 4%, 5%, or any value between 1% and 5%. The amount of coupling agent can be 1%, 2%, 3%, 4%, 5%, or any value between 1% and 5%. The amount of lubricant used can be 1%, 2%, 3%, or any value between 1% and 3%.

[0044] In an optional embodiment, the solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether acetate, dibutyl phthalate, butyl carbitol, and hexanediol.

[0045] In an optional embodiment, the thickener comprises ethyl cellulose. Ethyl cellulose is selected as the backbone to alter the viscosity of the slurry.

[0046] In an optional embodiment, the thixotropic agent includes at least one of hydrogenated castor oil and polyamide wax. This enables the organic carrier to possess better thixotropic properties.

[0047] In an optional embodiment, the surfactant comprises triethanolamine. This improves the flowability of the carrier and reduces the surface tension at the interface between the organic material and the solid particles.

[0048] In an optional embodiment, the coupling agent comprises silane coupling agent KH570. This ensures the adhesion strength and durability of the electrode paste to the silicon wafer surface.

[0049] In an optional embodiment, the lubricant includes at least one of calcium stearate and glyceryl monostearate. This can make the electrode paste fine, smooth, and non-sticky to the stencil, improving the printability of the electrode paste.

[0050] Organic carriers are an indispensable part of photovoltaic cell electrode slurries in Zhushan. Their main function is to disperse the mixture of conductive phase, binder phase, and inorganic solid particles into a slurry with fluid properties, ensuring uniform dispersion of the solid materials. Organic carriers have good viscosity and thixotropy, enabling them to better wet the solid particles in the slurry.

[0051] In one optional embodiment, the silver powder includes spherical silver powder and flake silver powder. The silver powder is required to be regular in shape, including both spherical and flake forms, and mixing the two can achieve a high tap density.

[0052] In one optional embodiment, the spherical silver powder has a particle size of D50 = 0.3-3.2 μm, and the flake silver powder has a particle size of 1.5-4 μm.

[0053] Optionally, the particle size of the spherical silver powder can be D50 = 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, 3μm, 3.1μm, 3.2μm, or D50 = 0. The particle size of the flake silver powder can be any value between 0.3 and 3.2 μm; the particle size can be D50 = 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, or any value between D50 = 1.5 and 4 μm.

[0054] In one optional embodiment, the tap density of the silver powder is greater than 4.5 g / cm³. 3 .

[0055] Optionally, the tap density of the silver powder can be 4.6 g / cm³. 3 4.7g / cm 3 4.8g / cm 3 4.9g / cm 3 5g / cm 3 5.1g / cm 3 5.2g / cm 3 5.3g / cm 3 5.4g / cm 3 5.5g / cm 3 5.6g / cm 3 5.7g / cm 3 5.8g / cm 3 5.9g / cm 3 6g / cm 3Or greater than 4.5 g / cm³ 3 Any value of .

[0056] The spherical silver powder has a particle size of D50 = 0.3-3.2 μm, the flake-shaped silver powder has a particle size of 1.5-4 μm, and the tap density of the silver powder is greater than 4.5 g / cm³. 3 The silver paste prepared under these conditions has good screen printing properties, high tap density, and balances electrical conductivity and solderability.

[0057] In an optional embodiment, the mass ratio of the spherical silver powder with a D50 of 0.3-0.7µm, preferably the spherical silver powder with a D50 of 0.50µm, the spherical silver powder with a D50 of 0.45-0.85µm, preferably the spherical silver powder with a D50 of 0.65µm, the spherical silver powder with a D50 of 2.12-2.52µm, preferably the spherical silver powder with a D50 of 2.32µm, the spherical silver powder with a D50 of 2.74-3.14µm, preferably the spherical silver powder with a D50 of 2.94µm, and the flake-shaped silver powder with a D50 of 1.5-4µm, is 20%:30%:10%:10%:30%.

[0058] In an optional embodiment, the glass powder has a particle size D50 of 0.3-3 μm.

[0059] Optionally, the particle size of the glass powder can be D50 = 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, 3μm, or any value between D50 = 0.3-3μm.

[0060] In one optional embodiment, the silver-copper alloy powder includes silver-copper binary alloy powder, silver-copper ternary alloy powder, and silver-copper quaternary alloy powder.

[0061] In one optional embodiment, the silver-copper alloy powder comprises 15% silver and 85% copper, based on 100% of its own mass.

[0062] In one optional embodiment, the silver-copper alloy powder has a particle size of 0.5-3.5 μm.

[0063] Optionally, the particle size of the silver-copper alloy powder can be 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, 3μm, 3.1μm, 3.2μm, 3.3μm, 3.4μm, 3.5μm, or any value between 0.5 and 3.5μm.

[0064] In one optional embodiment, the specific surface area of ​​the silver-copper alloy powder is 0.3-4 m². 2 / g.

[0065] Optionally, the specific surface area of ​​the silver-copper alloy powder can be 0.3 m². 2 / g, 0.4m 2 / g, 0.5m 2 / g, 0.6m 2 / g, 0.7m 2 / g, 0.8m 2 / g, 0.9m 2 / g、1m 2 / g, 1.1m 2 / g, 1.2m 2 / g, 1.3m 2 / g, 1.4m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.7m 2 / g, 1.8m 2 / g, 1.9m 2 / g、2m 2 / g、2.1m 2 / g, 2.2m 2 / g, 2.3m 2 / g, 2.4m 2 / g, 2.5m 2 / g, 2.6m 2 / g, 2.7m 2 / g, 2.8m 2 / g, 2.9m 2 / g、3m 2 / g, 3.1m 2 / g, 3.2m 2 / g, 3.3m 2 / g, 3.4m 2 / g, 3.5m 2 / g, 3.6m2 / g, 3.7m 2 / g, 3.8m 2 / g, 3.9m 2 / g、4m 2 / g, or 0.3-4m 2 Any value between / g.

[0066] Secondly, this application also provides a method for preparing a base metal paste for the main grid electrode of a photovoltaic cell, comprising: The organic carrier, silver powder, glass powder, and silver-copper alloy powder are mixed, dispersed, and ground to obtain a coarse slurry. The viscosity of the coarse slurry is adjusted to obtain the base metal slurry for the main grid electrode.

[0067] In one alternative embodiment, the silver powder is prepared by chemical reduction.

[0068] In an optional embodiment, the silver-copper alloy powder is prepared by mechanical alloying and / or atomization.

[0069] Mechanical alloying involves placing the mixed powders into a high-energy ball mill and milling them for an extended period under inert gas protection, allowing silver and copper atoms to fully diffuse and form an alloy. Atomization involves atomizing molten silver-copper alloy liquid into fine alloy powder using high-pressure gas. The prepared silver-copper alloy powder is then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations.

[0070] In one optional embodiment, the method for preparing the glass powder includes mixing the component compounds and melting them at 1200°C for 30 minutes until the component compounds are completely liquefied, followed by quenching, grinding, initial sieving, evaporation, and re-sieving to obtain the glass powder.

[0071] In an optional embodiment, based on 100% of the glass powder itself, the component compounds include PbO2 10.0-45.0%, SiO2 10.0-45.0%, PbO 10.0-35.0%, TeO2 10.0-35.0%, TiO2 5.0-20.0%, B2O3 5.0-15.0%, Bi2O3 5.0-10.0%, and ZnO 2.5-10.0%.

[0072] Optionally, based on the total mass of the glass powder (100%), the following components can be used: PbO2 can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or any value between 10% and 45%. SiO2 can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or any value between 10% and 45%. PbO can be 10%, 15%, 20%, 25%, 30%, 35%, or any value between 10% and 35%. TeO2 can be 10%, 15%, 20%, 25%, 30%, 35%, or any value between 10% and 35%. TiO2 can be 5%, 10%, 15%, 20%, or any value between 5% and 20%. B2O3 can be 5%, 10%, 15%, or any value between 5% and 15%. The amount of Bi2O3 can be 5%, 6%, 7%, 8%, 9%, 10%, or any value between 5% and 10%.

[0073] Weigh and mix the components, then place them in a crucible. First, preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and shaken well. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, screen out suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times will yield glass powders of different particle sizes. Use a 200-mesh sieve for preliminary sorting, then place them in a stainless steel tray and pour in alcohol. Place the tray in an oven to bake and evaporate for 1 hour to remove organic impurities. Then, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product.

[0074] Thirdly, this application also provides a photovoltaic cell main grid electrode, which is prepared from the photovoltaic cell main grid electrode base metal paste or the photovoltaic cell main grid electrode base metal paste prepared by the preparation method of the photovoltaic cell main grid electrode base metal paste.

[0075] Fourthly, this application also provides a photovoltaic cell, including the main grid electrode of the photovoltaic cell.

[0076] Fifthly, this application also provides a photovoltaic system, including the aforementioned photovoltaic cell.

[0077] The photovoltaic cell manufacturing method is shown below: (1) Silicon wafer cutting: high-quality silicon wafers are cut from pulled or cast silicon ingots.

[0078] (2) Cleaning and texturing: This process removes impurities and damaged layers from the silicon wafer surface, while simultaneously forming a light-trapping textured surface structure to increase light absorption and cell conversion efficiency. This step typically involves alkaline or acid texturing to create a regular textured surface structure.

[0079] (3) Diffusion: PN junctions are formed through phosphorus diffusion (P-type silicon wafers) or boron diffusion (N-type silicon wafers). The quality of the diffusion process directly affects the efficiency of the solar cell.

[0080] (4) Remove the parts of the silicon wafer with phosphorus or boron on the edge to avoid short circuit of the PN junction.

[0081] (5) A silicon nitride antireflective film is deposited on the surface of the silicon wafer to improve the absorption of sunlight and the generation of photocurrent in the solar cell. Common coating technologies include PECVD, LPCVD, etc.

[0082] (6) Passivation: Hydrogen atoms are doped into silicon nitride, which adds the passivation effect of hydrogen and helps to improve the open circuit voltage.

[0083] (7) Screen printing: The base metal paste material of the photovoltaic cell main grid electrode is printed onto the back electrode, back field and front grid. Drying treatment is required after printing.

[0084] (8) Sintering: The printed electrodes are sintered at high temperature to form an ohmic contact between the electrodes and the silicon wafer itself, thereby improving the open-circuit voltage and fill factor of the cell.

[0085] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0086] Example 1 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 1.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0087] Based on the organic carrier itself as 100% by weight, 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant are mixed to obtain the organic carrier.

[0088] 1.2 Preparation of silver powder A sample with a tap density of 5.2 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0089] 1.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0090] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.2 μm.

[0091] 1.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.0 μm, and the specific surface area was 1.5 m². 2 / g.

[0092] 1.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on 100% of the base metal paste for the photovoltaic cell main grid electrode, 10% organic carrier, 80% silver powder, 1.2% glass powder, and 8.8% silver-copper alloy powder were mixed and stirred evenly. The mixture was then slurried using a three-roll mill and filtered. The viscosity of the coarse slurry was tested, and after further slurry adjustment, the viscosity of the silver paste was adjusted to a usable state before being canned to obtain the main grid silver paste. The SEM image of the photovoltaic cell main grid electrode base metal paste particles after printing is shown below. Figure 1 As shown.

[0093] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0094] Example 2 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 2.1 Preparation of organic carriers The solvent, calculated based on 100% of the total organic carrier mass, includes: 60% terpineol, 5% dibutyl phthalate, and 5% butyl carbitol. The thickener is ethyl cellulose, the thixotropic agent is polyamide wax, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), and the lubricant is glyceryl monostearate.

[0095] Based on the organic carrier itself as 100% by weight, 70% solvent, 7% thickener, 20% thixotropic agent, 1% surfactant, 1% coupling agent, and 1% lubricant are mixed to obtain the organic carrier.

[0096] 2.2 Preparation of silver powder A sample with a tap density of 5.3 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0097] 2.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0098] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.5 μm.

[0099] 2.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.2 μm, and the specific surface area was 1.8 m². 2 / g.

[0100] 2.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Taking the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 12% organic carrier, 82% silver powder, 1% glass powder, and 5% silver-copper alloy powder are mixed and stirred evenly. After being slurried by a three-roll mill and filtered, the viscosity of the coarse paste is tested. After adjusting the viscosity of the silver paste to a better state for use, it is then bottled to obtain the main grid silver paste.

[0101] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0102] Example 3 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 3.1 Preparation of organic carriers Based on the total mass of the organic carrier itself (100%), the solvents include: 65% terpineol, 2.5% hexanediol, and 2.5% tributyl citrate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil and polyamide wax (mass ratio 1:1), the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Sinopharm Chemical Reagent Co., Ltd.), and the lubricant is calcium stearate and glyceryl monostearate (mass ratio 1:1).

[0103] Based on the organic carrier itself as 100% by weight, 70% solvent, 10% thickener, 17% thixotropic agent, 1% surfactant, 1% coupling agent, and 1% lubricant are mixed to obtain the organic carrier.

[0104] 3.2 Preparation of silver powder A sample with a tap density of 5.5 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0105] 3.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0106] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 0.8 μm.

[0107] 3.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 2 μm, and the specific surface area was 2.5 m².2 / g.

[0108] 3.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 10% organic carrier, 78% silver powder, 1.2% glass powder, and 10.8% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better state for use before being bottled to obtain the main grid silver paste.

[0109] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0110] Example 4 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 4.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 50% terpineol, 10% diethylene glycol butyl ether acetate, and 5% dibutyl phthalate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570, and the lubricant is calcium stearate.

[0111] Based on the organic carrier itself as 100% by weight, 65% solvent, 4% thickener, 20% thixotropic agent, 8% surfactant, 2% coupling agent, and 1% lubricant are mixed to obtain the organic carrier.

[0112] 4.2 Preparation of silver powder A sample with a tap density of 5.0 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0113] 4.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0114] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, screen out suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.0 μm.

[0115] 4.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.5 μm, and the specific surface area was 1.2 m². 2 / g.

[0116] 4.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 14% organic carrier, 75% silver powder, 1.1% glass powder, and 9.9% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better working state before being bottled to obtain the main grid silver paste.

[0117] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0118] Example 5 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 5.1 Preparation of Organic Carriers The solvent, based on 100% of the total organic carrier mass, includes: 45% terpineol, 15% butyl carbitol, and 10% hexanediol. The thickener is ethyl cellulose, the thixotropic agent is polyamide wax, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570, and the lubricant is glyceryl monostearate.

[0119] Based on the organic carrier itself as 100% by weight, 70% solvent, 11% thickener, 16% thixotropic agent, 1% surfactant, 1% coupling agent, and 1% lubricant are mixed to obtain the organic carrier.

[0120] 5.2 Preparation of silver powder A sample with a tap density of 5.1 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0121] 5.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0122] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, screen out suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.0 μm.

[0123] 5.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.5 μm, and the specific surface area was 1.2 m². 2 / g.

[0124] 5.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 11% organic carrier, 69% silver powder, 1% glass powder, and 19% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse paste is tested. After adjusting the viscosity of the silver paste to a better working state, it is then bottled to obtain the main grid silver paste.

[0125] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0126] Example 6 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 6.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 52% terpineol, 8% tributyl citrate, and 8% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agents are hydrogenated castor oil and polyamide wax (mass ratio 2:1), the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570, and the lubricant is calcium stearate.

[0127] The organic carrier is obtained by mixing 70% solvent, 10% thickener, 17% thixotropic agent, 1% surfactant, 1% coupling agent, and 1% lubricant, based on 100% of the organic carrier itself.

[0128] 6.2 Preparation of silver powder A sample with a tap density of 5.4 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0129] 6.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0130] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.3 μm.

[0131] 6.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for sufficient diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.8 μm, and the specific surface area was 1.6 m². 2 / g.

[0132] 6.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 13% organic carrier, 77% silver powder, 1.2% glass powder, and 8.8% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better working state before being bottled to obtain the main grid silver paste.

[0133] This embodiment also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above method.

[0134] Comparative Example 1 This comparative example provides a method for preparing a base metal paste for the main busbar electrode of a photovoltaic cell, the specific steps of which are as follows: 1.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0135] Based on the organic carrier itself (100% by weight), it includes: 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant.

[0136] 1.2 Preparation of silver powder A sample with a tap density of 5.0 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0137] 1.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0138] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for 1 hour to evaporate organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.4 μm.

[0139] 1.4 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100%, 18% organic carrier, 80.8% silver powder, 1.2% glass powder, and 0% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better state for use before being bottled to obtain the main grid silver paste.

[0140] This comparative example also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above-described method.

[0141] Comparative Example 2 This embodiment provides a method for preparing base metal paste for the main busbar electrode of a photovoltaic cell, and the specific steps are as follows: 2.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0142] Based on the organic carrier itself (100% by weight), it includes: 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant.

[0143] 2.2 Preparation of silver powder A sample with a tap density of 4.8 g / cm³ was prepared using a chemical reduction method. 3 The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0144] 2.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the constituent compounds include PbO2 (10%), SiO2 (40%), PbO (15%), TeO2 (10%), TiO2 (8%), B2O3 (10%), Bi2O3 (35%), and ZnO (2%).

[0145] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.6 μm.

[0146] 2.4 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 18% organic carrier, 75% silver powder, 1% glass powder, and 5% copper powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse paste is tested. After adjusting the paste, the viscosity of the silver paste is adjusted to a better state for use before being bottled to obtain the main grid silver paste.

[0147] This comparative example also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above-described method.

[0148] Comparative Example 3 This comparative example provides a method for preparing a base metal paste for the main busbar electrode of a photovoltaic cell, the specific steps of which are as follows: 3.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0149] Based on the organic carrier itself (100% by weight), it includes: 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant.

[0150] 3.2 Preparation of silver powder A sample with a tap density of 5.1 g / cm³ was prepared using a chemical reduction method. 3The silver powder contained monodisperse spherical silver powder with particle sizes of D50=0.50µm, D50=0.65µm, D50=2.0µm, and D50=2.94µm, and flake-shaped silver powder with a particle size of D50=3.68µm. The spherical silver powder with D50=0.50µm, D50=0.65µm, D50=2.32µm, D50=2.94µm, and D50=1.5-4µm flake-shaped silver powder were mixed in a mass ratio of 20%:30%:10%:10%:30%.

[0151] 3.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the components include 10% PbO2, 40% SiO2, 15% PbO, 10% TeO2, 8% TiO2, 9.5% B2O3, 35% Bi2O3, and 2.5% ZnO.

[0152] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.1 μm.

[0153] 3.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 50% silver and 50% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 2.5 μm, and the specific surface area was 1.0 m². 2 / g.

[0154] 3.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 12% organic carrier, 78% silver powder, 1.2% glass powder, and 8.8% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better state for use before being bottled to obtain the main grid silver paste.

[0155] This comparative example also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above-described method.

[0156] Comparative Example 4 This comparative example provides a method for preparing a base metal paste for the main busbar electrode of a photovoltaic cell, the specific steps of which are as follows: 4.1 Preparation of organic carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0157] Based on the organic carrier itself (100% by weight), it includes: 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant.

[0158] 4.2 Preparation of silver powder A sample with a tap density of 4.9 g / cm³ was prepared using a chemical reduction method. 3 Silver powder on the ball.

[0159] 4.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the constituent compounds include PbO2 (10%), SiO2 (40%), PbO (15%), TeO2 (10%), TiO2 (8%), B2O3 (10%), Bi2O3 (35%), and ZnO (2%).

[0160] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for evaporation for 1 hour to remove organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.3 μm.

[0161] 4.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.0 μm, and the specific surface area was 1.5 m². 2 / g.

[0162] 4.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 15% organic carrier, 80% silver powder, 1.2% glass powder, and 3.8% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better working state before being bottled to obtain the main grid silver paste.

[0163] This comparative example also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above-described method.

[0164] Comparative Example 5 This comparative example provides a method for preparing a base metal paste for the main busbar electrode of a photovoltaic cell, the specific steps of which are as follows: 5.1 Preparation of Organic Carriers Based on a total organic carrier mass of 100%, the solvents include: 55% terpineol, 5% tributyl citrate, and 5% diethylene glycol butyl ether acetate. The thickener is ethyl cellulose, the thixotropic agent is hydrogenated castor oil, the surfactant is triethanolamine, the coupling agent is silane coupling agent KH570 (purchased from Shanghai Jichun Industrial Co., Ltd.), and the lubricant is calcium stearate.

[0165] Based on the organic carrier itself (100% by weight), it includes: 70% solvent, 10% thickener, 15% thixotropic agent, 2% surfactant, 2% coupling agent, and 1% lubricant.

[0166] 5.2 Preparation of silver powder A sample with a tap density of 4.4 g / cm³ was prepared using a chemical reduction method. 3 Silver powder on the ball.

[0167] 5.3 Preparation of glass powder Based on the glass powder itself (100% by weight), the constituent compounds include PbO2 (10%), SiO2 (40%), PbO (15%), TeO2 (10%), TiO2 (8%), B2O3 (10%), Bi2O3 (35%), and ZnO (2%).

[0168] Weigh and mix the components, then place them in a crucible. Preheat the muffle furnace to 200°C, then raise the temperature to 1200°C at a rate of 10°C / min. Place the mixed raw materials in the crucible into the high-temperature muffle furnace and melt for 30 minutes until the glass material is completely liquefied and well mixed. Remove the crucible and pour the molten glass into prepared deionized distilled water for quenching. Then, select suitable glass blocks and place them in a zirconium jar for ball milling in a planetary ball mill. Different grinding times yield glass powders of different particle sizes. Use a 200-mesh sieve for initial sorting, then place the powder in a stainless steel tray, add alcohol, and bake in an oven for 1 hour to evaporate organic impurities. Finally, use a 500-mesh sieve to sieve the powder to obtain the final glass powder product. The obtained glass powder has a particle size of D50 = 1.4 μm.

[0169] 5.4 Preparation of silver-copper alloy powder Based on the silver-copper alloy powder itself (100% by weight), 15% silver and 85% copper were mixed and then placed in a high-energy ball mill. The mixture was ball-milled for an extended period under nitrogen protection to allow for full diffusion of silver and copper atoms to form an alloy. The prepared silver-copper alloy powder was then sieved and graded to select alloy powder with a suitable particle size range for subsequent preparations. The particle size was D50 = 1.0 μm, and the specific surface area was 1.5 m². 2 / g.

[0170] 5.5 Preparation of Base Metal Paste for Photovoltaic Cell Busbar Electrode Based on the base metal paste of the photovoltaic cell main grid electrode as 100% by weight, 15% organic carrier, 78% silver powder, 1.2% glass powder, and 5.8% silver-copper alloy powder are mixed and stirred evenly. After being slurried using a three-roll mill and filtered, the viscosity of the coarse slurry is tested. After adjusting the slurry, the viscosity of the silver paste is adjusted to a better working state before being bottled to obtain the main grid silver paste.

[0171] This comparative example also provides a photovoltaic cell, which can be prepared by setting parameters in accordance with the above-described method.

[0172] The performance parameters of the photovoltaic cells prepared in Examples 1-6 and Comparative Examples 1-5 are shown in Table 1: Table 1 Performance parameters of photovoltaic cells prepared in Examples 1-6 and Comparative Examples 1-5

[0173] As shown in Table 1, the photovoltaic cells prepared using the base metal paste of this application in Examples 1-6 have a photoelectric conversion efficiency of 26.53%-26.57%, an open-circuit voltage of 0.7410-0.7420V, a short-circuit current of 15.780-15.820A, a fill factor of 86.48%-86.58%, a series resistance of 0.90Ω, a welding pull force of 3.3-3.7N, and a cost reduction of 15%-19% compared to traditional silver paste. In comparison, Comparative Example 1, without the addition of silver-copper alloy powder, achieved an efficiency of only 26.20%, with no cost reduction; Comparative Example 2, by replacing some silver powder with copper powder, experienced a significant performance decrease, with the efficiency dropping to 25.50%; Comparative Example 3, by adjusting the silver-copper alloy ratio, did not achieve the same level of performance and cost optimization as the examples; Comparative Examples 4 and 5 failed to meet the requirements in terms of silver powder characteristics, and their performance was also inferior to the examples. It is evident that the slurry formulation and process of this application can effectively improve photovoltaic cell performance and reduce costs.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0175] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A base metal paste for the main busbar electrode of a photovoltaic cell, characterized in that, Based on its own weight as 100%, it includes 5-20% organic carrier, 75-85% silver powder, 1-1.2% glass powder, and 5-20% silver-copper alloy powder.

2. The photovoltaic cell main grid electrode base metal paste according to claim 1, characterized in that, The organic carrier, by its own weight (100%), comprises 60-70% organic solvent, 5-20% thickener, 10-30% thixotropic agent, 1-5% surfactant, 1-5% coupling agent, and 1-3% lubricant, and satisfies at least one of the following conditions: a. The solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether acetate, dibutyl phthalate, butyl carbitol, and hexanediol; b. The thickener includes ethyl cellulose; c. The thixotropic agent includes at least one of hydrogenated castor oil and polyamide wax; d. The surfactant includes triethanolamine; e. The coupling agent includes silane coupling agent KH570; f. The lubricant includes at least one of calcium stearate and glyceryl monostearate.

3. The photovoltaic cell main grid electrode base metal paste according to claim 1, characterized in that, The silver powder includes spherical silver powder and flake silver powder, and satisfies at least one of the following conditions: g. The spherical silver powder has a particle size of D50 = 0.3-3.2 μm, and the flake silver powder has a particle size of D50 = 1.5-4 μm; h. The tap density of the silver powder is greater than 4.5 g / cm³. 3 ; i. The mass ratio of the spherical silver powder with D50=0.3-0.7µm, the spherical silver powder with D50=0.45-0.85µm, the spherical silver powder with D50=2.12-2.52µm, the spherical silver powder with D50=2.74-3.14µm, and the flake-shaped silver powder with D50=1.5-4µm is 20%:30%:10%:10%:30%.

4. The photovoltaic cell main grid electrode base metal paste according to claim 1, characterized in that, The glass powder has a particle size D50 of 0.3-3 μm.

5. The photovoltaic cell main grid electrode base metal paste according to any one of claims 1-4, characterized in that, At least one of the following conditions must be met: l. The silver-copper alloy powder includes silver-copper binary alloy powder, silver-copper ternary alloy powder, and silver-copper quaternary alloy powder; m. Based on the mass of the silver-copper alloy powder itself (100%), it comprises 15% silver and 85% copper; n. The particle size of the silver-copper alloy powder is D50 = 0.5-3.5 μm; o. The specific surface area of ​​the silver-copper alloy powder is 0.3-4 m². 2 / g.

6. A method for preparing the base metal paste for the main grid electrode of a photovoltaic cell according to any one of claims 1-5, characterized in that, include: The organic carrier, silver powder, glass powder, and silver-copper alloy powder are mixed, dispersed, and ground to obtain a coarse slurry. The viscosity of the coarse slurry is adjusted to obtain the base metal slurry for the main grid electrode.

7. The method for preparing the base metal paste for the photovoltaic cell main grid electrode according to claim 6, characterized in that, At least one of the following conditions must be met: p. The silver powder is prepared by chemical reduction. q. The silver-copper alloy powder is prepared by mechanical alloying and / or atomization. r. The method for preparing the glass powder includes mixing the component compounds and melting them at 1200°C for 30 minutes until the component compounds are completely liquefied, followed by quenching, grinding, initial sieving, evaporation, and re-sieving to obtain the glass powder; the compounds, based on 100% of the glass powder itself, include PbO2 10.0-45.0%, SiO2 10.0-45.0%, PbO 10.0-35.0%, TeO2 10.0-35.0%, TiO2 5.0-20.0%, B2O3 5.0-15.0%, Bi2O3 5.0-10.0%, and ZnO 2.5-10.0%.

8. A photovoltaic cell main grid electrode, characterized in that, The photovoltaic cell main grid electrode base metal paste is prepared by the preparation method of the photovoltaic cell main grid electrode base metal paste according to any one of claims 1-5 or any one of claims 6-7.

9. A photovoltaic cell, characterized in that, Includes the photovoltaic cell main grid electrode as described in claim 8.

10. A photovoltaic system, characterized in that, Includes the photovoltaic cell described in claim 9.

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