Metallized conductive paste, conductive electrode, solar cell and preparation method

Abstract

The invention discloses metallized conductive paste, a conductive electrode, a solar cell and a preparation method, and belongs to the field of solar photovoltaic cells. The metallized conductive paste includes a glass frit accounting for 1 wt% to 4 wt% of total solids in the metallized conductive paste; the glass frit at least comprises 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B2O3, 5 mol% to 32 mol% of SiO2, 1.8 mol% to 15 mol% of Fe2O3 and 1 mol% to 5 mol% of Al2O3 based on the molar percentage of the glass frit; the conductive metal source accounts for 81 wt%-91 wt% of total solids in the metallized conductive paste; and an organic component accounting for 8 wt% to 15 wt% of the total solid content in the metallized conductive paste. According to the invention, the acetic acid resistance, chemical durability and long-term reliability of the battery can be improved.

Description

Technical Field

[0001] This application belongs to the technical field of solar photovoltaic cells, and specifically relates to metallized conductive pastes, conductive electrodes, solar cells and preparation methods. Background Art

[0002] Solar photovoltaic cells need to be exposed to a complex outdoor environment for a long time. Therefore, photovoltaic modules need to have good long-term reliability and weather resistance. One of the mechanisms leading to the efficiency degradation of photovoltaic modules is the corrosion of the battery metal electrodes by acetic acid. Among them, acetic acid is a product formed by the decomposition of the ethylene-vinyl acetate (EVA) film, which is the encapsulation material of the module. Acetic acid will corrode the metal electrodes, increase the contact resistance, and cause serious loss of the photoelectric conversion efficiency of the photovoltaic cells. Summary of the Invention

[0003] Object of the Invention: The embodiments of this application provide a metallized conductive paste, a conductive electrode, a solar cell and a preparation method, aiming to provide higher acid resistance attenuation ability for photovoltaic cells while maintaining higher photoelectric conversion efficiency.

[0004] Technical Solution: The metallized conductive paste described in the embodiments of this application includes:

[0005] Frit, accounting for 1 wt% to 4 wt% of the total solids in the metallized conductive paste; based on the mole percentage of the frit, the frit includes at least 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3

[0006] Conductive metal source, accounting for 81 wt% to 91 wt% of the total solids in the metallized conductive paste; and

[0007] Organic component, accounting for 8 wt% to 15 wt% of the total solids in the metallized conductive paste.

[0008] In some embodiments, in the frit, the iron element in the Fe 2 O 3 is used to form Fe-O-Si bonds, Fe-O-B bonds and a combination of Fe-O-Si bonds and Fe-O-B bonds with the boron element in the B 2 O 3 and the silicon element in the SiO 2 respectively.

[0009] In some embodiments, based on the molar percentage of the glass material, the glass material further includes Bi in an amount less than or equal to 12 mol %. 2 O 3 .

[0010] In some embodiments, based on the molar percentage of the glass frit, the glass frit comprises 25 mol % to 55 mol % of PbO, 25 mol % to 45 mol % of B 2 O 3 , 5mol% to 32mol% SiO 2 , 1.8mol% to 15mol% Fe 2 O 3 and 1 mol% to 5 mol% Al 2 O 3 composition.

[0011] In some embodiments, based on the molar percentage of the glass frit, the glass frit comprises 25 mol % to 55 mol % of PbO, 25 mol % to 45 mol % of B 2 O 3 , 5mol% to 32mol% SiO 2 , 1.8mol% to 15mol% Fe 2 O 3 , 0mol% to 12mol% Bi 2 O 3 and 1 mol% to 5 mol% Al 2 O 3 composition.

[0012] In some embodiments, the metallized conductive paste further comprises:

[0013] The additive accounts for 0.05wt% to 0.5wt% of the total solid content in the metallized conductive paste; wherein the additive is selected from at least one of aluminum element and aluminum alloy powder.

[0014] In some embodiments, the conductive metal source is selected from any one or a mixture of silver, silver alloy, silver oxide and silver salt.

[0015] In some embodiments, the present application further provides a conductive electrode, comprising:

[0016] A semiconductor substrate, the semiconductor substrate comprising a stacked substrate, a p-type doping layer and a passivation layer, wherein the p-type doping layer is located between the substrate and the passivation layer;

[0017] A first conductive structure penetrates the passivation layer and forms an electrical connection with the p-type doped layer, and the first conductive structure is formed by the metallized conductive paste.

[0018] In some embodiments, the substrate includes an n-type doped semiconductor substrate.

[0019] In some embodiments, the present application further provides a solar cell, and the solar cell includes the conductive electrode.

[0020] In some embodiments, the solar cell is a solar cell with a tunneling oxide layer passivation contact structure.

[0021] In some embodiments, the conversion efficiency of the solar cell is Eff 1 ; the conductive electrode is placed in an environment with a pH less than 7 for treatment, and after treatment, the conversion efficiency of the solar cell is Eff 2 ; the solar cell further satisfies: -30% < (Eff 2 - Eff 1 ) / Eff 1 < -5%.

[0022] In some embodiments, the steps of the treatment specifically refer to: treating at a temperature of 80°C to 90°C for 5h to 10h.

[0023] In some embodiments, the present application further provides a method for manufacturing a solar cell, including:

[0024] Providing a semiconductor substrate, the semiconductor substrate includes a substrate, a p-type doped layer, and a passivation layer arranged in a stacked manner, and the p-type doped layer is located between the substrate and the passivation layer;

[0025] Applying the metallized conductive paste to at least a part of the surface of the passivation layer;

[0026] Sintering the semiconductor substrate coated with the metallized conductive paste, so that the metallized conductive paste etches and penetrates the passivation layer during sintering to form a first conductive structure that makes electrical connection with the p-type doped layer;

[0027] After sintering, laser scanning the semiconductor substrate and applying a reverse voltage to the semiconductor substrate to form an induced current in the first conductive structure to obtain the solar cell.

[0028] In some embodiments, the time of the laser scanning is 1ms to 100ms, and the reverse voltage is 5V to 15V.

[0029] Advantageous effects: Compared with the prior art, the metallized conductive paste of the present application comprises: a glass frit, accounting for 1 wt% to 4 wt% of the total solids in the metallized conductive paste; based on the mole percentage of the glass frit, the glass frit comprises at least 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3 ; a conductive metal source, accounting for 81 wt% to 91 wt% of the total solids in the metallized conductive paste; and an organic component, accounting for 8 wt% to 15 wt% of the total solids in the metallized conductive paste. In the metallized conductive paste of the present application, by adding Fe 2 O 3 to the glass frit, which serves as an intermediate oxide, a distorted iron oxygen tetrahedron is formed and composes a continuous and stable glass network structure with silicon oxygen and boron oxygen tetrahedrons, thereby enabling the glass frit to form a more compact glass structure, which helps to improve the acetic acid resistance, chemical durability and long-term reliability of the subsequent preparation of solar cells.

[0030] It can be understood that the conductive electrode, solar cell and their preparation methods provided by the embodiments of the present application may include all the technical features and advantageous effects of the above metallized conductive paste, which will not be elaborated herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0032] Figure 1 is a cross-sectional view of the conductive electrode provided by the embodiment of the present application;

[0033] Figure 2 is the EL image before and after acetic acid attenuation provided by the embodiment of the present application;

[0034] Reference numerals: 10 - semiconductor substrate, 20 - first conductive structure, 30 - second conductive structure, 101 - substrate, 102 - p-type doping layer, 103 - passivation layer, 104 - tunneling layer, 105 - n + polycrystalline silicon layer, 106 - passivation film. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0036] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In the description of the present application, "a plurality of" means two or more, and at least one means one, two or more, unless otherwise specifically defined.

[0037] The applicant has found that photovoltaic modules need to be exposed to complex outdoor environments for a long time, so photovoltaic modules need to have good long-term reliability and weather resistance. In outdoor operation and accelerated damp heat tests, one of the most common component efficiency degradation mechanisms is the corrosion of the battery metal electrodes by acetic acid. Acetic acid is a product formed by the decomposition of ethylene-vinyl acetate (EVA) film, a commonly used component encapsulation material in the market. Acetic acid will corrode the photovoltaic cells and metal electrodes, increasing the contact resistance and resulting in a loss of photoelectric conversion efficiency. Among different solar cell technologies, including Passivated Emitter Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), and Heterojunction with Intrinsic Thin-film (HJT), the acetic acid attenuation of the front metal electrodes of TOPCon cells is particularly severe.

[0038] In the process of preparing TOPCon cells, during the screen printing metallization process, there is usually a residual glass layer at the interface between the sintered metal grid lines and the silicon wafer after high-temperature rapid firing. This residual glass layer connects the metal and the silicon, and its function and stability are crucial. However, acetic acid can degrade the interface glass layer to form holes or gaps, resulting in an increase in contact resistance and thus a loss of efficiency. The composition of this residual glass layer mainly comes from the glass powder used in the paste composition. Therefore, the composition of the glass powder in the paste is crucial for the acetic acid resistance of the metal electrodes. TOPCon cell P +The glass frit commonly used in the front metallization paste is lead-silicon-boron oxide (Pb-B-Si-O). For lead-boron-silicon oxide, the stability of its glass network structure is the main factor affecting its acetic acid resistance; however, some optional network modifier oxides, such as alkali metal oxides (Li 2 O, Na 2 O, K 2 O, etc.) and alkaline earth metal oxides (CaO, BaO, MgO, SrO, etc.), will break the borosilicate network connection and result in poorer acetic acid resistance.

[0039] Based on this, it is necessary to provide a metallization conductive paste, a conductive electrode, a solar cell and a preparation method, which improve the glass frit containing lead-silicon-boron oxide, achieve higher acetic acid attenuation resistance of the solar cell and maintain a higher photoelectric conversion efficiency.

[0040] The metallization conductive paste provided by some embodiments of the present application includes a glass frit, a conductive metal source and an organic component; the glass frit accounts for 1 wt% to 4 wt% of the total solids in the metallization conductive paste; based on the mole percentage of the glass frit, the glass frit includes at least 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3 ; the conductive metal source accounts for 81 wt% to 91 wt% of the total solids in the metallization conductive paste; the organic component accounts for 8 wt% to 15 wt% of the total solids in the metallization conductive paste.

[0041] Among them, the glass frit and the conductive metal source are solid components in the conductive paste; the organic component is the dispersed phase in the conductive paste composition and provides printing performance, including one or more components such as polymers, surfactants, thickeners, thixotropic agents, and binders that can endow functional properties. The sum of the weight percentages of each component in the conductive paste is 100%.

[0042] Each component will be described separately below.

[0043] Glass frit

[0044] In some embodiments, the glass frit refers to a composition containing one or more types of anions and cations. The glass frit has the ability to flow when heated, and the glass frit can be crystalline or partially or completely glassy or amorphous. In some embodiments, the glass refers to the form of particulate solids,

[0045] In some embodiments, the frit of this embodiment can be understood as a composition having a glass composition, and the mass percentage of the frit in the conductive paste composition is 1 wt% to 4 wt%; in some other embodiments, the mass percentage of the frit in the conductive paste composition is 1.2 wt% to 3.8 wt%, and can also be 1.5 wt% to 3.5 wt%; it can further be 2.0 wt% to 3.0 wt%; it can further be 2.2 wt% to 2.8 wt%. It can be understood that the adjustment of the proportion of the frit in the conductive paste composition needs to ensure that the sum of the weight percentages of the components in the conductive paste composition is 100%. The components of the frit directly affect its fusibility, fluidity, and etchability. Therefore, the components of the frit need to have a good balance to achieve an excellent carrier recombination effect.

[0046] In some embodiments, the frit includes at least 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3 . In the following description, unless otherwise specified, "mol%" of the content of each component of the frit represents the mole percentage calculated in terms of oxide conversion.

[0047] In some embodiments, further preferably, calculated in terms of mole percentage of oxide conversion, the frit includes: 25 mol% to 50 mol% of PbO, 30 mol% to 40 mol% of B 2 O 3 , 10 mol% to 30 mol% of SiO 2 , 3 mol% to 10 mol% of Fe 2 O 3 and 3 mol% to 4.5 mol% of Al 2 O 3 .

[0048] In some embodiments, further preferably, calculated in terms of mole percentage of oxide conversion, the frit includes: 30 mol% to 45 mol% of PbO, 35 mol% to 40 mol% of B 2 O 3 , 15 mol% to 25 mol% of SiO 2 , 3 mol% to 8 mol% of Fe 2 O 3and 3.5 mol% to 4 mol% of Al 2 O 3 。

[0049] It should be noted that in the metallized conductive paste of the present application, by adding Fe 2 O 3 to the frit, as an intermediate oxide, it forms a distorted iron oxygen tetrahedron and composes a continuous and stable glass network structure with silicon oxygen and boron oxygen tetrahedrons. Due to the smaller radius of Fe ions, the binding of the Fe-O bond is stronger, thus forming a more compact glass structure. This more stable Fe-O-B bond and Fe-O-Si bond, compared with the B-O-B bond and Si-O-Si bond, contribute to improving the chemical durability of the material, thereby enabling the frit to form a more compact glass structure, which helps to improve the acetic acid resistance and long-term reliability of the paste.

[0050] In some embodiments, in the frit, the iron element in Fe 2 O 3 is used to form Fe-O-Si bonds, Fe-O-B bonds, and a combination of Fe-O-Si bonds and Fe-O-B bonds with the boron element in B 2 O 3 and the silicon element in SiO 2 respectively. It can be understood that compared with the B-O-B or Si-O-Si bond, the incorporation of Fe 2 O 3 can form more stable Fe-O-Si bonds and Fe-O-B bonds. By forming Fe-O-Si bonds and Fe-O-B bonds, the iron element is interconnected with boron and silicon elements in Fe 2 O 3 to form a stable glass network structure. This network structure can improve the structural stability and mechanical strength of the material. Secondly, the formation of Fe-O-Si bonds and Fe-O-B bonds improves the chemical stability of the material, enabling it to better resist the erosion of environmental media such as acids, which helps to improve the durability and long-term service life of the material. At the same time, the introduction of iron elements can adjust the energy band structure of the material and improve the optoelectronic conversion performance. Through the combination of Fe-O-Si bonds and Fe-O-B bonds, the generated local charges can optimize the energy band structure and charge transport characteristics of optoelectronic devices, thereby improving the optoelectronic conversion efficiency.

[0051] In some embodiments, the frit of the present application is formed by adding Fe 2 O 3 to the base raw material containing lead-silicon-boron oxides to form a frit containing lead-iron-boron-silicon oxides.

[0052] In some embodiments, PbO contained in the frit of the present application is the main component controlling the corrosiveness of the glass, which enables etching of the passivation layer. PbO is also an intermediate glass former that can be incorporated into the glass network, and the residual PbO will exist outside the glass framework to act as a glass modifier.

[0053] In some embodiments, B contained in the frit of the present application 2 O 3 is the main glass former for controlling the glass transition temperature Tg and the high-temperature fluidity of the glass. B 2 O 3 can form a low-melting-point glass and provide good fluidity. B 2 O 3 can also form a network structure, which helps to stabilize the glass and at the same time can improve the bonding ability between the molten glass and the substrate.

[0054] In some embodiments, SiO contained in the frit of the present application 2 acts as a glass former to adjust the glass transition temperature Tg and the high-temperature fluidity of the glass. Appropriate addition can stabilize the glass phase, increase the glass melting point and reduce the fluidity. SiO 2 can also improve the weather resistance of the glass and adjust the reaction ability with the substrate.

[0055] In some embodiments, Fe contained in the frit of the present application 2 O 3 as an intermediate oxide can significantly enhance the acetic acid resistance of the glass while achieving excellent electrical performance.

[0056] In some embodiments, based on the mole percentage of the frit, the frit further includes Bi with a content less than or equal to 12 mol% 2 O 3 . Bi 2 O 3 can be used to partially replace PbO to adjust the corrosiveness of the frit. And when the frit contains both PbO and Bi 2 O 3 , both of them can corrode the passivation layer during the sintering process because PbO and Bi 2 O 3 have reactivity with the passivation layer and have the function of improving the softening fluidity of the glass. In addition, since the corrosiveness of PbO is stronger than that of Bi 2 O 3 , replacing a part of PbO with Bi 2 O 3 in the composition of the frit can adjust the corrosion ability to meet the effect of low carrier recombination and can improve the open-circuit voltage and the photoelectric conversion efficiency of the battery.

[0057] In some embodiments, Bi 2 O 3 can further form an interface similar to a "barrier layer" with Fe 2 O 3 to block the entry of oxygen, acidic gases or moisture, reduce the oxidation rate on the surface of the glass powder, and thus improve the stability of the material. Bi 2 O 3 and Fe 2 O 3 After combination, the local environment inside the crystal can be changed by regulating the lattice structure and atomic arrangement mode, thereby adjusting the stability of the material. This combination can optimize the grain boundary structure, reduce the grain boundary energy and grain boundary sensitivity, and improve the stability of the material.

[0058] In some embodiments, further optionally, the glass frit further includes Bi 2 O 3 with a content greater than or equal to 2 mol% and less than or equal to 8 mol%.

[0059] In some embodiments, based on the mole percentage of the glass frit, the glass frit consists of 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3 . Based on this, the glass frit only contains PbO, B 2 O 3 , SiO 2 , Fe 2 O 3 and Al 2 O 3 and the total mole percentage sum is 100%. At this time, Fe 2 O 3 can form more stable bonding bonds with B 2 O 3 and SiO 2 to prevent corrosion by external factors and improve the chemical durability of the glass powder.

[0060] In some embodiments, Al 2 O 3 , as an intermediate glass oxide, can also be incorporated in an appropriate amount to adjust the glass transition temperature Tg and high-temperature fluidity of the glass, and can also be used as a component to improve the weather resistance of the glass.

[0061] In some embodiments, Al 2 O 3 itself has good chemical stability and, when combined with Fe 2 O 3 can form a barrier layer to block the penetration of external chemical substances, slowing down or preventing the chemical reaction of the glass powder. Moreover, the combination of Al 2 O 3 and Fe 2 O 3 can introduce a structure strengthening effect based on a physical mechanism, making the structure of the glass powder more stable.

[0062] In some embodiments, based on the mole percentage of the glass frit, the glass frit consists of 25 mol% to 55 mol% of PbO, 25 mol% to 45 mol% of B 2 O 3 , 5 mol% to 32 mol% of SiO 2 , 1.8 mol% to 15 mol% of Fe 2 O 3 , 0 mol% to 12 mol% of Bi 2 O 3 and 1 mol% to 5 mol% of Al 2 O 3 components. Based on this, the glass frit contains only PbO, B 2 O 3 , SiO 2 , Fe 2 O 3 , Bi 2 O 3 and Al 2 O 3 and the total mole percentage sum is 100%.

[0063] Conductive metal source

[0064] In some embodiments, as the conductive source of the conductive paste, the conductive metal source can be a metal powder commonly used in electrodes formed on circuit substrates such as semiconductor substrates without particular limitation. Exemplary metals include but are not limited to silver, gold, copper, nickel, palladium, platinum, aluminum, and their alloys and mixtures. Alternatively, the conductive component consists essentially of silver, depending on its excellent processability and high conductivity.

[0065] In some embodiments, the conductive metal source accounts for 81 wt% to 91 wt% of the total solids in the metallized conductive paste; in some other embodiments, the conductive metal source accounts for 82 wt% to 90 wt% of the total solids in the metallized conductive paste, and can also be 83 wt% to 89 wt%; it can further be 84 wt% to 88 wt%. It can be understood that the adjustment of the proportion of the conductive metal source in the conductive paste needs to ensure that the sum of the weight percentages of the components in the conductive paste is 100%. The conductive metal source is used to play a conductive role after the formation of the solar cell.

[0066] In some embodiments, the conductive metal source can be selected as metal powder, or can also be a mixture directly combining two or more such metals or alloys; the metal is provided by a metal oxide or salt, and the metal oxide or salt decomposes when exposed to firing heat to form the metal. When the metal powder is silver powder, it should be understood to refer to elemental silver metal, silver alloys, silver oxides or silver salts, and their mixtures, and can further include those derived from silver oxide (Ag 2 O or AgO) or silver salts such as AgCl, AgNO 3 , AgOOCCH 3 (silver acetate), AgOOCF 3 (silver trifluoroacetate), Ag 3 PO 4 (silver orthophosphate), or their mixtures. Any other form of conductive metal compatible with other components of the metallized conductive paste can also be used in certain embodiments, and other metals used in the paste of the present application for functional conductive materials can be obtained similarly.

[0067] In some embodiments, the conductive metal source can be provided as finely dispersed particles with the following morphologies, such as powder form, flake form, spherical form, rod form, granular form, nodular form, layered or coated form, other irregular forms, or their mixtures.

[0068] In some embodiments, the median particle size of the conductive metal source is in the range of 0.5 - 3.5 μm. The median particle size is D50, which refers to the 50% volume distribution size. Further preferably, the conductive metal source uses spherical silver powder with a median particle size of 1 - 3 μm; even more preferably, the conductive metal source uses spherical silver powder with a median particle size of 1.5 - 2.5 μm; even more preferably, the spherical silver powder with a median particle size of 2 μm. The main role of the silver powder is to form a high-density silver body after sintering to improve good conductivity, and the spherical silver powder with a median particle size of 2 μm can also inhibit agglomeration and ensure uniform dispersion of the silver powder.

[0069] In some embodiments, when the conductive metal source is in powder form, it can be in a coated or uncoated form; for example, it can be at least partially coated with a surfactant to facilitate processing. Suitable coating surfactants include, for example, stearic acid, palmitic acid, stearates, palmitates, and mixtures thereof. Other surfactants that can also be used include lauric acid, oleic acid, capric acid, myristic acid, linoleic acid, and mixtures thereof. Other surfactants that can also be used include polyethylene oxide, polyethylene glycol, benzotriazole, poly(ethylene glycol) acetic acid, and other similar organic molecules. Suitable counter-ions used in the coating surfactant include, but are not limited to, hydrogen, ammonium, sodium, potassium, and mixtures thereof. For example, when the conductive metal source is silver, it can be coated with a phosphorus-containing compound.

[0070] Organic component

[0071] In some embodiments, the organic component accounts for 8 wt% to 15 wt% of the total solids in the metallized conductive paste. In some other embodiments, it can also be 9 wt% to 14 wt%. It can further be 10 wt% to 13 wt%.

[0072] In some embodiments, relative to the solids composed of the conductive metal source and the frit, the organic component serves as the liquid phase in the conductive paste to disperse the above-mentioned solids to form a paste with a certain viscosity. The viscosity and rheology of the paste can both enable the above-mentioned conductive metal source and frit to be stably dispersed therein for a long time, and enable the conductive paste composition to be dispersed on the printing screen, and apply the desired pattern to the surface of the passivation layer of the substrate in a screen printing manner.

[0073] In some embodiments, the organic component can include polymers and organic solvents. Polymers can include cellulose, resins, esters, etc. Cellulose includes cellulose-based resins such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, benzyl cellulose, propyl cellulose, nitrocellulose, or mixtures thereof. Resins include wood rosin, phenolic resins, acrylic resins, or mixtures thereof. Esters include polymethacrylates of lower alcohols, etc. Organic solvents can include terpineol, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol diacetate, α-terpinene, β-terpinene, dibutyl phthalate, butyl carbitol, butyl carbitol acetate, hexylene glycol, etc.

[0074] In some embodiments, the organic component has a consistency and rheology that make it suitable for printing methods, including but not limited to screen printing. The organic medium can also include other additives such as non-ionic surfactants, thixotropic agents, dispersants, rheological agents, etc. to adapt to the organic medium with different requirements.

[0075] Additive

[0076] In some embodiments, the metallized conductive paste further includes an additive, which accounts for 0.05 wt% to 0.5 wt% of the total solids in the metallized conductive paste; wherein, the additive is selected from at least one of elemental aluminum and aluminum alloy powder. During the firing process, the Al or Al alloy powder helps to adjust the corrosiveness of the molten glass. During firing, Al is oxidized to Al 2 O 3 and incorporated into the molten glass batch, thereby further adjusting the fluidity and corrosiveness of the glass melt.

[0077] Further optionally, the additive accounts for 0.1 wt% to 0.3 wt% of the total solids in the metallized conductive paste.

[0078] In some embodiments, the glass powder can be prepared by using methods commonly used in the field of glass manufacturing. For example, according to the oxide corresponding to the composition ratio of the glass powder described in the embodiment, ingredients are proportioned, mixed, added to a crucible (such as a platinum or ceramic crucible), heated to the peak temperature (for example, 800 °C to 1400 °C) and maintained for a period of time to melt the oxides together inside. The molten material can then be quenched in any suitable manner, including but not limited to passing it between reversely rotating stainless steel rollers to form flakes with a thickness of 0.25 to 0.50 mm, pouring it onto a thick stainless steel plate, or pouring it into water. Then the obtained glass batch is ground by common grinding techniques to form a powder with a particle size of 0.5 μm to 2 μm. Common grinding techniques such as jet milling, ball milling, sand milling or planetary milling.

[0079] In some embodiments, the preparation method of the conductive paste may include: proportioning and stirring and dispersing according to the paste components described in the embodiment, then dispersing and grinding with a three-roll mill to a fineness of less than 10 μm, and then further filtering. For the addition amounts of the glass batch and aluminum powder in some embodiments, there will be differences. In these cases, silver powder is used for equal replacement, and the amounts of other components such as organic components remain unchanged. The adjustment of the ratio of the glass batch, conductive metal source, organic component and additive needs to ensure that the sum of the mass percentages of each component in the conductive paste is 100%.

[0080] Conductive electrode

[0081] In some embodiments, referring to Figure 1 , this embodiment further provides a conductive electrode, which includes a semiconductor substrate 10 and a first conductive structure 20. The semiconductor substrate 10 includes a substrate 101, a p-type doped layer 102 and a passivation layer 103 arranged in a stacked manner. The p-type doped layer 102 is located between the substrate 101 and the passivation layer 103; the first conductive structure 20 penetrates the passivation layer 103 and forms an electrical connection with the p-type doped layer 102. The first conductive structure 20 is formed by sintering the metallized conductive paste of this embodiment.

[0082] It is understandable that the first conductive structure 20 can form an electrical connection with a p-type semiconductor with low carrier recombination. The p-type semiconductor can be the p-type doped layer 102, and the substrate 101 can be an n-type doped semiconductor substrate 101. In addition, in a TOPCon cell, the p-type doped layer 102 is also referred to as a p-type emitter.

[0083] Solar cell

[0084] As Figure 1 shown, some embodiments of the present application provide a solar cell, which is a solar cell with a tunnel oxide passivated contact structure (Tunnel Oxide Passivated Contacts), and the above-mentioned metallized conductive paste is utilized during its preparation.

[0085] In some embodiments, a solar cell containing a tunnel oxide passivated contact structure is referred to as a TOPCon solar cell (Tunnel Oxide Passivated Contact Solar Cell). This kind of solar cell utilizes the tunnel oxide layer as a charge transport channel and a surface passivation layer to improve the efficiency and performance of the cell. The TOPCon solar cell structure has low electron reflection and surface recombination, and at the same time has a high photoelectric conversion efficiency and low electron defects.

[0086] In some embodiments, in a TOPCon solar cell, the semiconductor substrate 10 further includes: a tunneling layer 104 (such as an ultra-thin silicon dioxide layer), which is located on the back surface of the n-type doped semiconductor substrate 101; + a polycrystalline silicon layer 105 (such as a phosphorus-doped polycrystalline silicon layer), which is located on the surface of the tunneling layer 104 away from the n-type doped semiconductor substrate 101; a passivation film 106, which is deposited on the + surface of the polycrystalline silicon layer away from the tunneling layer 104; and a second conductive structure 30, the second conductive structure 30 penetrates at least a part of the passivation film 106 and forms an electrical connection with the + polycrystalline silicon layer.

[0087] In some embodiments, the front side refers to the light-receiving surface of the solar cell and is also the working surface of the solar cell. The back side is the back surface of the solar cell and usually does not directly receive light. The metallized conductive paste of the present application can be used to form a conductive structure on the front side. The front side can be the Figure 1 upper surface in

[0088] In some embodiments, the tunneling layer 104 and the + polycrystalline silicon layer 105 are formed by the tunnel oxide passivated contact method.

[0089] In some embodiments, the first conductive structure 20 is formed by using the metallized conductive paste of this embodiment. The conductive paste composition is applied to at least a part of the surface of the passivation layer 103 in a desired patterned form. During the sintering process, the conductive paste penetrates the passivation layer 103 to obtain the first conductive structure 20 that forms an electrical connection with the p-type doped layer 102 with low carrier recombination.

[0090] In some embodiments, the second conductive structure 30 can use a commercially available metallized silver paste applied to p-type or n-type crystalline silicon cells, such as a silver paste containing PbTeO glass powder. The conductive paste composition is applied to at least a part of the surface of the passivation film in a desired patterned form. During the sintering process, the silver paste containing PbTeO glass powder etches and penetrates the passivation film 106, thereby + forming an electrical contact with the polycrystalline silicon layer 105 to facilitate the formation of the second conductive structure 30 in the form of a conductive metal contact.

[0091] In some embodiments, the conversion efficiency of the solar cell is Eff 1 ; the conductive electrode is treated in an environment with a pH less than 7, and after treatment, the conversion efficiency of the solar cell is Eff 2 ; the solar cell further satisfies: -30% < (Eff 2 - Eff 1 ) / Eff 1 < -5%. Wherein, (Eff 2 - Eff 1 ) / Eff 1 is used to characterize the attenuation degree of the conversion efficiency of the solar cell before and after treatment in an acidic environment, that is, the attenuation rate. It can be understood that when -30% < (Eff 2 - Eff 1 ) / Eff 1 < -5% is satisfied, it shows that in this embodiment, by adding Fe 2 O 3 to the glass frit, the acid resistance of the glass can be significantly enhanced and the excellent electrical performance of the solar cell can be maintained.

[0092] In some embodiments, the conversion efficiency Eff 1 or Eff 2 can be obtained according to the records in GB / T18911-2002. Standard test conditions: AM1.5, 1000 W / m 2 , 25 °C.

[0093] In some embodiments, the step of treating in an acidic environment specifically refers to: setting the solar cell facing an acidic source, the acidic source volatilizing an acidic medium and contacting the first conductive structure on the surface of the solar cell, with the specific treatment temperature in the range of 80°C to 90°C and the treatment time being 5h to 10h. Among them, the acidic source can be acetic acid, etc.

[0094] An embodiment of the present application provides a method for manufacturing a solar cell, including:

[0095] 1) Provide a semiconductor substrate 10, the semiconductor substrate 10 includes a substrate 101, a p-type doped layer 102, and a passivation layer 103 arranged in a stacked manner, and the p-type doped layer 102 is located between the substrate 101 and the passivation layer 103; wherein, a trivalent element (such as boron or gallium) is doped on the front surface of the substrate 101, so as to form a p-type doped layer 102 on the front surface of the n-type doped semiconductor substrate 101; the passivation layer 103 is deposited on the surface of the p-type doped layer 102 by a deposition method;

[0096] 2) Apply the metallized conductive paste provided in this embodiment onto the passivation layer 103; specifically, apply the metallized conductive paste onto at least a part of the surface of the passivation layer 103 in a patterned form; the patterning method can be screen printing; it can be understood that the conductive paste composition involved in this embodiment is used as a fine grid for the front (P side) of a solar cell with a tunneling oxide layer passivation contact structure, and passes through four screen printers corresponding to the back main grid, back fine grid, front main grid, and front fine grid respectively; the conductive paste of this embodiment is used for the front fine grid, usually the fourth front fine grid, and after each printing, drying is carried out and then the next paste is printed;

[0097] 3) Sinter the semiconductor substrate 10 and the metallized conductive paste group, so that the metallized conductive paste etches and penetrates the passivation layer 103 during sintering to form a first conductive structure 20 that is electrically connected to the p-type doped layer 102; in addition, the preparation of the second conductive structure 30 is the same as that of the first conductive structure 20;

[0098] 4) After sintering, perform laser scanning on the semiconductor substrate 10 and apply a reverse voltage to the semiconductor substrate 10 to form an induced current in the first conductive structure 20, thereby obtaining a solar cell.

[0099] The serial numbers of the above steps are not regarded as limiting the order of the steps.

[0100] In some embodiments, step 4) is a method for optimizing laser-enhanced contact, which is a method of using laser in the manufacturing process of solar cells to improve the electrical contact of metallization paste. The basic principle of laser-enhanced contact improvement technology is to utilize a large number of carriers generated by the laser. By applying a bias voltage, these carriers are guided through the formed metallization contact points, and the heat energy generated by the current is used to improve the contact effect and uniformity. It can improve the uniformity of electrical contact, reduce contact defects, thereby improving the efficiency and reliability of solar cells. In this technology, the injection amount of carriers can be controlled by parameters such as laser power and time to achieve better contact uniformity and improvement effect.

[0101] In some embodiments, the laser scanning time is from 1 ms to 100 ms, and the reverse voltage is from 5 V to 15 V. Using the laser-enhanced contact optimization technology to process the conductive structure can reduce the contact resistance, which is more conducive to the increase of open-circuit voltage and the improvement of efficiency.

[0102] The technical solutions of the present application will be further described below in conjunction with specific embodiments.

[0103] The component contents of the frit in Examples 1 to 10 and the frit in Comparative Examples 1 to 3 are shown in Table 1. The sum of the components in the frit of the examples and comparative examples is 100 mol%. Among them, the lead-iron-boron-silicon oxides in Examples 1 to 10 cover different mol% contents of Fe 2 O 3 ; Examples 7 and 8 correspond to different SiO 2 contents to adjust the high-temperature physical properties of the glass powder; Example 9 uses Bi 2 O 3 to replace a part of PbO to control the corrosiveness of the frit; Example 10 uses Al 2 O 3 to be incorporated to adjust the high-temperature physical properties of the glass powder. Comparative Example 1 does not contain Fe 2 O 3 ; Comparative Example 2 is a glass powder containing ZnO, and ZnO also has the properties of intermediate oxides; Comparative Example 3 contains Fe 2 O 3 but the content is 1 mol%, which does not meet the scope defined in the present application.

[0104] Table 1

[0105] mol% PbO <![CDATA[Bi 2 O 3 > <![CDATA[B 2 O 3 > <![CDATA[SiO 2 > <![CDATA[Al 2 O 3 > <![CDATA[Fe 2 O 3 > ZnO Total Example 1 53.4 / 35.6 7.0 1.0 3.0 / 100.0 Example 2 52.2 / 34.8 7.0 1.0 5.0 / 100.0 Example 3 51.0 / 34.0 7.0 1.0 7.0 / 100.0 Example 4 49.8 / 33.2 7.0 1.0 9.0 / 100.0 Example 5 48.6 / 32.4 7.0 1.0 11.0 / 100.0 Example 6 47.4 / 31.6 7.0 1.0 13.0 / 100.0 Example 7 35.0 / 25.0 32.0 1.0 7.0 / 100.0 Example 8 34.0 / 42.0 16.0 1.0 7.0 / 100.0 Example 9 25.0 12.0 40.0 15.0 1.0 7.0 / 100.0 Example 10 34.0 / 40.0 14.0 5.0 7.0 / 100.0 Comparative Example 1 55.2 / 36.8 7.0 1.0 / / 100.0 Comparative Example 2 52.2 / 34.8 7.0 1.0 / 5.0 100.0 Comparative Example 3 53.4 / 37.6 7.0 1.0 1.0 / 100.0

[0106] The glass powder stability test was carried out on Examples 1 to 6 and Comparative Examples 1 to 3 in Table 1. The specific test process was as follows: 2.5 grams of the glass materials of the corresponding embodiments and comparative examples were taken and soaked in 0.1 wt% acetic acid (49.95 grams of pure water, 0.05 grams of acetic acid) for 12 hours, and then the upper layer of water was separated by centrifugation. The metal Pb, B, Fe and Zn contents (ppm) in the upper layer of water were detected by ICP. The experimental results are shown in Table 2 below, where ND means not detected.

[0107] Table 2

[0108]

[0109]

[0110] It can be seen from Table 2 that by adding Fe 2 O 3 As intermediate oxides, the decomposed B and Pb are significantly lower, and the glass frit is more stable. 2 O 3 As the amount of addition increases, the precipitated Pb and B further decrease, indicating that its stability is better; Comparative Example 1 does not contain Fe 2 O 3 , the most precipitated Pb and B, the glass material stability is poor; Comparative Example 2 contains 5mol% ZnO, which slightly improves the stability of the glass material; Comparative Example 3 contains 1mol% Fe 2 O 3 , there is also a certain improvement effect, but due to Fe 2 O 3 The amount of is insufficient, so more Pb and B are precipitated.

[0111] The frit materials of Examples 1 to 10 and Comparative Examples 1 to 3 in Table 1 were used to prepare metallized conductive pastes, and solar cells were fabricated. Corresponding Examples 11 to 25 and Comparative Examples 4 to 6 were obtained. In the following examples, the composition of the conductive paste can be adjusted accordingly to obtain suitable properties that meet the requirements. For example, the amount of the frit material can be easily adjusted according to the final usage requirements. The specific contents are shown in Table 3. Among them, the conductive metal source is spherical silver powder with an average particle size of 0.5 to 3 μm. The organic components specifically include: 1.5 wt% ethyl cellulose, 1.5 wt% polyvinyl butyral copolymer (PVB), 1.6 wt% diethylene glycol butyl ether acetate, 0.3 wt% silicone oil, 0.15 wt% Duomeen TDO (a non-ionic surfactant belonging to the amine oxide category), 0.15 wt% Brij L4 (a non-ionic surfactant belonging to the polyoxyethylene alcohol category), 0.4 wt% Thixotrol plus (a rheology modifier), 2.8 wt% ethoxylated alcohol C12, 0.6 wt% diester, and the rest is solvent. The specific preparation process of the conductive paste composition is as follows: The above components are proportioned and stirred and dispersed, then dispersed and ground with a three-roll mill to a fineness of less than 10 μm, and then further filtered to obtain it.

[0112] Table 3

[0113]

[0114]

[0115] In Table 3, the frit materials of Examples 21 to 25 were obtained by blending the frit materials of Example 3 and Comparative Example 1. Therefore, for the composition of the frit materials corresponding to Examples 21 to 25, refer to Table 4.

[0116] Table 4

[0117] mol% PbO <![CDATA[Bi 2 O 3 > <![CDATA[B 2 O 3 > <![CDATA[SiO 2 > <![CDATA[Al 2 O 3 > <![CDATA[Fe 2 O 3 > ZnO Total Example 21 54.1 / 36.1 7.0 1.0 1.8 / 100.0 Example 22 53.6 / 35.7 7.0 1.0 2.6 / 100.0 Example 23 53.1 / 35.4 7.0 1.0 3.5 / 100.0 Example 24 52.6 / 35.0 7.0 1.0 4.4 / 100.0 Example 25 52.0 / 34.7 7.0 1.0 5.3 / 100.0

[0118] The preparation of the solar cell is as follows: First, prepare the blue film of the TOPCon cell, and pass it through four screen printers corresponding to the back main grid, back fine grid, front main grid, and front fine grid respectively; apply the conductive paste composition to the front fine grid of the P side; sinter the blue film and the conductive paste, so that the conductive paste composition etches the passivation layer during the sintering process to obtain a conductive structure formed on the p side of the blue film; perform laser enhanced contact optimization on the conductive structure to fabricate the solar cell.

[0119] Among them, the blue film is a commercially available semi-finished TOPCon solar cell. The blue film has an n-type substrate silicon wafer with a TOPCon cell structure, that is, a tunnel oxide passivated back surface with an n-doped polysilicon layer, and the n-doped polysilicon is passivated by a dielectric layer. The front is based on a B-diffused emitter, and the emitter is also passivated by a dielectric layer. The dielectric insulation layer usually includes SiN x 、SiN x O y 、Al 2 O 3 or a combination thereof.

[0120] In the metalization process, a 4-pass printing machine is used for screen printing. High-temperature sintering uses a commercially available Meyer Burger sintering furnace with an 18-zone furnace temperature; the laser contact enhancement technology is a post-treatment for enhancing the contact of the sintered cell.

[0121] Based on the components in Table 3, an additive in the range of 0.05 wt% to 0.5 wt% can also be added to the prepared metallization conductive paste, and it is ensured that the sum of the masses of each component is 100%. The process of preparing the battery is the same as the above process.

[0122] Solar Cell Performance Evaluation

[0123] The photoelectric conversion efficiency of the cell is tested using a commercially available IV tester. The test items include efficiency (Eff), open-circuit voltage (Voc), fill factor (FF), and current (Isc).

[0124] Electroluminescence imaging or EL imaging: Too high contact resistance will cause dark areas or foggy black phenomena to appear in the EL imaging.

[0125] Acetic Acid Attenuation Experiment

[0126] The acetic acid attenuation test is a method for evaluating the moisture and acid stability of the metallized cell. The specific acetic acid attenuation method includes:

[0127] (1) Prepare the solution: Add 120 grams of potassium chloride and 500 grams of pure water to a 50-liter sealed box and mix, then add 25 grams of acetic acid;

[0128] (2) Prepare a flower basket suitable for the size of the cell silicon wafer. Keep the front and back directions of all cells consistent and the main grid lines perpendicular to the bottom. The spacing grid of the cells is about 5 mm. Place the flower basket with the cells in the middle of the sealed box. The distance between the liquid level and the cells is about 5 cm. Seal the box and then gently transfer it to the oven. Use a constant current source to supply the internal fan equipment of the sealed box. Place it in the oven at 85 °C for 6 hours. Then take out the cells and test the performance data of the cells after the acetic acid test and calculate the attenuation rate (Eff 2 -Eff1 ) / Eff 1 。

[0129] For specific evaluation results, refer to Table 5 and Table 6.

[0130] Table 5

[0131] Example ΔEff ΔVoc ΔFF ΔIsc Example 11 0.11 0.0021 0.08 0.005 Example 12 0.08 0.0027 0.00 -0.005 Example 13 0.07 0.0025 -0.09 0.007 Example 14 0.07 0.0029 -0.08 -0.003 Example 15 0.07 0.0031 -0.08 -0.002 Example 16 0.10 0.0036 -0.05 -0.004 Example 17 0.25 0.0158 -0.50 -0.078 Example 18 0.33 0.0148 -0.16 -0.073 Example 19 0.17 0.0151 -0.72 -0.068 Example 20 0.31 0.0141 -0.19 -0.066 Example 21 0.020 0.001 -0.038 0.003 Example 22 0.009 0.001 -0.047 -0.002 Example 23 0.022 0.001 -0.057 0.000 Example 24 0.067 0.002 0.028 0.004 Example 25 0.082 0.002 0.025 0.010 Comparative Example 4 0.00 0.0000 0.00 0.000 Comparative Example 5 0.01 0.0014 -0.11 0.000 Comparative Example 6 0.07 0.0013 0.02 -0.001

[0132] Refer to Table 5. ΔEff, ΔVoc, and ΔFF in Table 5 respectively refer to the differences obtained after uniformly comparing the data of the corresponding test examples for efficiency (Eff), open-circuit voltage (Voc), and fill factor (FF) with that of Comparative Example 4. Examples 11 to 20 have the advantage of higher efficiency compared to Comparative Examples 4 to 6, indicating that different Fe 2 O 3 mol% contents of the frit can keep the battery having a relatively high battery efficiency, because of the increase in the open-circuit voltage Voc. From Examples 21 to 25, it can be seen that the frit containing Fe 2 O 3 can be used alone or mixed with other glasses. The metallized conductive paste adopted in the examples of the present application can help keep the solar cell having a relatively high conversion efficiency.

[0133] Table 6

[0134]

[0135] Refer to Table 6. Compared with the data of Comparative Examples 4 to 6, the attenuation rates of the solar cells provided by Examples 11 to 26 of the present application satisfy the range of being greater than -30% and less than -5%, and the degree of attenuation is lower. Among them, Examples 11 to 15 correspond to adding Fe in the range of 3 mol% to 15 mol% 2 O 3 , all showing significant improvement effects on acid resistance; from Examples 21 to 25, it can be seen that by adding Fe at a certain mixing ratio 2 O 3 significant attenuation improvement effects can also be achieved. There is no Fe 2 O 3 in Comparative Example 4, and the attenuation rate is -37%; ZnO, which can be used as an intermediate oxide, is adopted in Comparative Example 5, but the attenuation rate is still relatively high at 39%, indicating that Fe 2 O 3 can improve the chemical stability of the glass structure, but ZnO cannot improve the chemical stability of the glass structure; the frit of Comparative Example 6 contains 1 mol% of Fe 2 O 3, although the acetic acid resistance has been somewhat improved, the overall attenuation rate of -30% is still relatively high and does not meet the requirements of practical applications. In summary, in this application, due to the addition of Fe 2 O 3 , as an intermediate oxide, it forms a distorted iron oxygen tetrahedron and composes a continuous and stable glass network structure with silicon oxygen and boron oxygen tetrahedrons. Due to the relatively small radius of Fe ions, the Fe-O bond has a stronger binding force, thus forming a more compact glass structure, which helps to improve the chemical durability of the material, and thus makes the frit form a more compact glass structure, improving the acetic acid resistance and long-term reliability of the solar cell.

[0136] See further Figure 2 , which are EL images before and after acetic acid attenuation. The contact resistance after acetic acid in Comparative Examples 4 and 5 is significantly affected. The higher contact resistance results in obvious fog black in the EL images, which is consistent with the significant decrease in FF after acetic acid in the I-V curve.

[0137] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0138] The above has introduced in detail the metallized conductive paste, conductive electrode, solar cell and preparation method provided by the embodiments of the present application, and specific examples have been used to elaborate the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A metallized conductive paste, characterized in that: include: Glass frit, accounting for 1 wt % to 4 wt % of the total solids in the metallized conductive paste; Based on the molar percentage of the glass frit, the glass frit includes at least 25 mol % to 55 mol % of PbO, 25 mol % to 45 mol % of B2O3, 5 mol % to 32 mol % of SiO2, 1.8 mol % to 15 mol % of Fe2O3 and 1 mol % to 5 mol % of Al2O3; A conductive metal source, which accounts for 81 wt % to 91 wt % of the total solids in the metallized conductive paste; as well as The organic component accounts for 8wt% to 15wt% of the total solid content in the metallization conductive paste.

2. The metallized conductive paste according to claim 1, characterized in that: In the glass frit, the iron element in the Fe2O3 is used to form Fe-O-Si bonds, Fe-OB bonds, and a combination of Fe-O-Si bonds and Fe-OB bonds with the boron element in the B2O3 and the silicon element in the SiO2, respectively.

3. The metallized conductive paste according to claim 1, characterized in that: Based on the molar percentage of the glass material, the glass material further includes Bi2O3 in an amount less than or equal to 12 mol%.

4. The metallized conductive paste according to claim 1, characterized in that: The glass frit consists of 25 mol % to 55 mol % of PbO, 25 mol % to 45 mol % of B2O3, 5 mol % to 32 mol % of SiO2, 1.8 mol % to 15 mol % of Fe2O3, and 1 mol % to 5 mol % of Al2O3, based on mole percentage of the glass frit.

5. The metallized conductive paste according to claim 3, characterized in that: The glass frit consists of 25 mol % to 55 mol % of PbO, 25 mol % to 45 mol % of B2O3, 5 mol % to 32 mol % of SiO2, 1.8 mol % to 15 mol % of Fe2O3, 0 mol % to 12 mol % of Bi2O3 and 1 mol % to 5 mol % of Al2O3, based on the mol % of the glass frit.

6. The metallized conductive paste according to claim 1, characterized in that: The metallized conductive paste also includes: The additive accounts for 0.05wt% to 0.5wt% of the total solid content in the metallized conductive paste; wherein the additive is selected from at least one of aluminum element and aluminum alloy powder.

7. The metallized conductive paste according to claim 1, characterized in that: The conductive metal source is selected from any one or a mixture of silver, silver alloy, silver oxide and silver salt.

8. A conductive electrode, characterized in that: include: A semiconductor substrate, the semiconductor substrate comprising a stacked substrate, a p-type doping layer and a passivation layer, wherein the p-type doping layer is located between the substrate and the passivation layer; A first conductive structure penetrates the passivation layer and forms an electrical connection with the p-type doping layer, wherein the first conductive structure is formed by the metallized conductive paste according to any one of claims 1 to 7.

9. The conductive electrode according to claim 8, characterized in that The substrate includes an n-type doped semiconductor substrate.

10. A solar cell, characterized in that: The solar cell comprises the conductive electrode according to claim 8 or 9.

11. The solar cell according to claim 10, characterized in that The solar cell is a solar cell having a tunneling oxide layer passivation contact structure.

12. The solar cell according to claim 10, characterized in that: The conversion efficiency of the solar cell is Eff1; the conductive electrode is placed in an environment with a pH value less than 7 for treatment, and after the treatment, the conversion efficiency of the solar cell is Eff2; the solar cell further satisfies: -30%<(Eff2-Eff1) / Eff1<-5%.

13. The solar cell according to claim 12, characterized in that: The treatment step specifically refers to: treating at a temperature of 80° C. to 90° C. for 5 h to 10 h.

14. A method for preparing a solar cell, characterized in that: include: Providing a semiconductor substrate, the semiconductor substrate comprising a stacked substrate, a p-type doping layer and a passivation layer, wherein the p-type doping layer is located between the substrate and the passivation layer; Applying the metallized conductive paste according to any one of claims 1 to 7 to at least a portion of the surface of the passivation layer; Sintering the semiconductor substrate coated with the metallized conductive paste, so that the metallized conductive paste etches and penetrates the passivation layer during the sintering process to form a first conductive structure electrically connected to the p-type doped layer; After sintering, the semiconductor substrate is laser scanned, and a reverse voltage is applied to the semiconductor substrate to form an induced current in the first conductive structure to obtain the solar cell.

15. The method for preparing a solar cell according to claim 14, characterized in that: The laser scanning time is 1ms to 100ms, and the reverse voltage is 5V to 15V.

Images