Silver nickel paste, preparation method thereof and N-type crystalline silicon solar cell

Abstract

This invention discloses a silver-nickel paste and its preparation method, as well as an N-type crystalline silicon solar cell. In this silver-nickel paste, the mass percentage of organic additives is between 1.5% and 2%; the mass percentage of micron-sized spherical silver powder is between 55% and 65%; the mass percentage of micron-sized spherical nickel powder is between 6% and 20%; the mass percentage of nano-sized spherical silver powder is between 1% and 2%; the mass percentage of organic modifier is between 0.1% and 0.6%; the mass percentage of organic binder is between 9% and 35%; and the mass percentage of glass powder is between 1.5% and 2%. This silver-nickel paste improves the resistance to acetic acid, reduces the aging risk of damp-heat degradation in the prepared solar cells, and solves the problem of increased production costs due to the high cost of pure silver paste.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to a silver-nickel paste and its preparation method, and an N-type crystalline silicon solar cell. Background Technology

[0002] The continuous upgrading and iteration of photovoltaic cell structures has led to the accumulation of outdated production capacity, making cost reduction and efficiency improvement a key concern in the photovoltaic industry. Compared with P-type crystalline silicon cells, N-type crystalline silicon cells have a longer minority carrier lifetime, no light-induced degradation, better performance in low light conditions, and a smaller temperature coefficient, making them the hope for crystalline silicon solar cells to break through the theoretical maximum efficiency.

[0003] The back grid electrode of existing N-type crystalline silicon solar cells mainly uses silver paste. The wet weight of the silver paste for each cell is approximately 40 mg, while the unit price of silver paste is approximately 26,000 yuan / kg. This translates to a cost of 1.04 yuan per cell for the back grid electrode. The current unit price of a finished solar cell is approximately 3.25 yuan / cell. Therefore, the cost of the back grid electrode accounts for a significant proportion of the total cost of the finished solar cell, impacting the manufacturer's profitability and economic efficiency. Furthermore, the existing silver paste has poor acetic acid resistance, leading to damp heat aging and even significant performance degradation in the cells, failing to meet the market's increasing requirements for damp heat aging resistance.

[0004] Therefore, there is an urgent need to find a metal paste that has improved acetic acid resistance, is inexpensive, and has good conductivity to replace pure silver paste, and to apply this metal paste to the fabrication of the back grid electrode of N-type crystalline silicon solar cells. Summary of the Invention

[0005] This invention provides a silver-nickel paste and its preparation method, as well as an N-type crystalline silicon solar cell. Compared with expensive pure silver paste, the inexpensive silver-nickel paste can maintain or even improve the photoelectric conversion efficiency of the finished cell, and also reduce the manufacturing cost of the finished cell.

[0006] In a first aspect, embodiments of the present invention provide a silver-nickel paste, comprising organic additives, micron-sized spherical silver powder, a modified nickel-silver mixture, an organic binder, and glass powder, wherein the modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier; wherein, The organic additive is present in the silver-nickel paste at a mass percentage between 1.5% and 2%. The mass percentage of the micron-sized spherical silver powder in the silver-nickel paste is between 55% and 65%. The mass percentage of the micron-sized spherical nickel powder in the silver-nickel paste is between 6% and 20%. The mass percentage of the nano-sized spherical silver powder in the silver-nickel paste is between 1% and 2%. The organic modifier is present in the silver-nickel paste at a mass percentage between 0.1% and 0.6%. The organic binder is present in the silver-nickel paste at a mass percentage between 9% and 35%. The glass powder constitutes a mass percentage of 1.5% to 2% in the silver-nickel paste.

[0007] Optionally, the organic modifier includes lauryl ether phosphate.

[0008] Optionally, the organic additive includes at least one of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, lauryl phosphate, silicone oil, diester, lauryl phosphate diester, and a mixture of BYK-115.

[0009] Optionally, the organic adhesive comprises a polymer and an organic solvent; wherein, The polymer is present in the organic adhesive at a mass percentage between 6% and 10%. The organic solvent in the organic adhesive is between 90% and 94% by mass.

[0010] Optionally, the organic solvent includes at least five of the following: terpineol, butylcarbiol, butylcarbiol acetate, tributyl citrate, Span 85, and 12-ol ester.

[0011] Optionally, the glass powder includes Bi2O3, Al2O3, SiO2, ZnO, Sb2O5, B2O3, TeO3, and PbO; wherein, The mass percentage of Bi2O3 in the glass powder is between 10% and 20%. The mass percentage of AL2O3 in the glass powder is between 15% and 22%. The mass percentage of SiO2 in the glass powder is between 10% and 20%. The ZnO in the glass powder is between 12% and 15% by mass; The mass percentage of Sb2O5 in the glass powder is between 15% and 20%. The mass percentage of B2O3 in the glass powder is between 10% and 20%. The mass percentage of TeO3 in the glass powder is between 8% and 10%. The mass percentage of PbO in the glass powder is between 10% and 20%.

[0012] Optionally, the particle size range of the glass powder is 2μm to 2.2μm.

[0013] Secondly, embodiments of the present invention also provide a method for preparing a silver-nickel paste, used to prepare the silver-nickel paste as described in any one of the first aspects, the method comprising: Micron-sized spherical nickel powder and nano-sized spherical silver powder are mixed with organic modifiers to prepare modified nickel-silver mixtures; The organic binder and glass powder are mixed and dispersed to obtain a uniformly mixed first powder. Micron-sized spherical silver powder and the modified nickel-silver mixture are added to the first powder, and the first powder, the micron-sized spherical silver powder and the modified nickel-silver mixture are dispersed and ground to obtain a uniformly mixed second powder; An organic additive is added to the second powder, and the second powder and the organic additive are dispersed to obtain a uniformly mixed silver-nickel paste.

[0014] Optionally, micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier are mixed to prepare a modified nickel-silver mixture, comprising: The micron-sized spherical nickel powder, the nano-sized spherical silver powder, the organic modifier, and alcohol are added together into a ball mill for grinding. The zirconia balls inside the ball mill after grinding were cleaned with pure water to obtain a turbid liquid; The turbid liquid was evaporated and dried to obtain a solid. The solid material is ground and sieved to obtain the modified nickel-silver mixture.

[0015] Thirdly, embodiments of the present invention also provide an N-type crystalline silicon solar cell, including a back grid line electrode, wherein the back grid line electrode is prepared using silver-nickel paste as described in any one of the first aspects.

[0016] This invention provides a silver-nickel paste and its preparation method, as well as an N-type crystalline silicon solar cell. The silver-nickel paste includes organic additives, micron-sized spherical silver powder, a modified nickel-silver mixture, an organic binder, and glass powder. The modified nickel-silver mixture includes micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The organic additives constitute 1.5% to 2% of the silver-nickel paste by mass; the micron-sized spherical silver powder constitutes 55% to 65% of the silver-nickel paste by mass; the micron-sized spherical nickel powder constitutes 6% to 20% of the silver-nickel paste by mass; the nano-sized spherical silver powder constitutes 1% to 2% of the silver-nickel paste by mass; the organic modifier constitutes 0.1% to 0.6% of the silver-nickel paste by mass; the organic binder constitutes 9% to 35% of the silver-nickel paste by mass; and the glass powder constitutes 1.5% to 2% of the silver-nickel paste by mass. This silver-nickel paste uses a modified nickel-silver mixture. To better bond the micron-sized spherical nickel powder and nano-sized spherical silver powder during sintering, after mixing the micron-sized spherical nickel powder and nano-sized spherical silver powder, the mixture is ball-milled using zirconium oxide. During the ball milling process, an organic modifier is added to modify the nickel-silver powder, increasing the acetic acid resistance of the prepared silver-nickel paste, reducing the resistivity of the corresponding grid lines, improving the fill factor, reducing the aging risk of damp heat degradation in the prepared solar cells, and allowing nano-sized spherical silver powder to adhere to the surface of the micron-sized spherical nickel powder, thus achieving fusion of the micron-sized spherical nickel powder and nano-sized spherical silver powder. Furthermore, this embodiment provides a low-cost and high-quality silver-nickel paste. Applying this silver-nickel paste to the fabrication process of the back grid electrode of an N-type crystalline silicon solar cell solves the problem of increased production costs due to the high cost of existing pure silver paste. Compared to expensive pure silver paste, using nickel powder to replace a portion of the silver powder in pure silver paste (e.g., a replacement ratio of 6% to 20%) effectively reduces the amount and cost of silver powder used. This low-cost silver-nickel paste can maintain or even improve the high photoelectric conversion efficiency of N-type crystalline silicon solar cells, achieving a long lifespan and maintaining a stable short-circuit current. By controlling the open-circuit voltage, the fill factor can be stabilized, thus ensuring the stability of the photoelectric conversion efficiency of N-type crystalline silicon solar cells. This also reduces the manufacturing cost of N-type crystalline silicon solar cells, achieving cost optimization and thus improving the overall cost-effectiveness of the final N-type crystalline silicon solar cells. This enhances the competitiveness of N-type crystalline silicon solar cells in the industry. Furthermore, the back side of N-type crystalline silicon solar cells has lower requirements for parameters such as light utilization and shading area, which provides a favorable opportunity for the application of silver-nickel paste in the preparation of the back grid electrodes of N-type crystalline silicon solar cells.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of a method for preparing silver-nickel paste according to an embodiment of the present invention; Figure 2 This is a schematic flowchart of another method for preparing silver-nickel paste provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] First, it should be noted that this embodiment of the invention provides a silver-nickel paste for use as the back grid electrode of an N-type crystalline silicon solar cell. On the one hand, compared to expensive pure silver paste, the inexpensive silver-nickel paste can maintain or even improve the high photoelectric conversion efficiency of N-type crystalline silicon solar cells, solving the problem of increased production costs due to the high cost of existing pure silver paste. On the other hand, this embodiment illustrates that the silver-nickel paste can be applied to the fabrication process of the back grid electrode of an N-type crystalline silicon solar cell. It is understood that compared to the requirements for light utilization rate and light-transmitting area on the front side of an N-type crystalline silicon solar cell, the requirements for light utilization rate and light-transmitting area on the back side are lower, and the printing precision requirements for the back grid electrode are also lower. This provides a favorable opportunity for the application of silver-nickel paste in the fabrication of the back grid electrode of an N-type crystalline silicon solar cell.

[0023] The silver-nickel paste provided in this embodiment of the invention comprises organic additives, micron-sized spherical silver powder, modified nickel-silver mixture, organic binder, and glass powder. The modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and organic modifier. The organic additives constitute 1.5% to 2% of the silver-nickel paste by mass; the micron-sized spherical silver powder constitutes 55% to 65% of the silver-nickel paste by mass; the micron-sized spherical nickel powder constitutes 6% to 20% of the silver-nickel paste by mass; the nano-sized spherical silver powder constitutes 1% to 2% of the silver-nickel paste by mass; the organic modifier constitutes 0.1% to 0.6% of the silver-nickel paste by mass; the organic binder constitutes 9% to 35% of the silver-nickel paste by mass; and the glass powder constitutes 1.5% to 2% of the silver-nickel paste by mass.

[0024] In this silver-nickel paste, micron-sized spherical silver powder forms the conductive matrix. The mass percentage of micron-sized spherical silver powder in the paste can be adjusted according to conductivity requirements. The particle size of the micron-sized spherical silver powder directly affects the conductivity of the paste. Generally, smaller particles provide a larger surface area, offering more contact points, reducing resistance, and thus improving conductivity efficiency—in other words, better conductivity. For example, the particle size range of the micron-sized spherical silver powder can be 3μm to 4μm. Furthermore, higher purity of the micron-sized spherical silver powder results in better conductivity of the prepared silver-nickel paste, which in turn improves the conductivity of the back grid electrode of the N-type crystalline silicon solar cell. This effectively improves the power utilization rate of the N-type crystalline silicon solar cell and extends its lifespan. For example, the purity of the micron-sized spherical silver powder can be 99.9% or higher.

[0025] The silver-nickel paste in this embodiment can be understood as being prepared by replacing some of the silver powder in pure silver paste with nickel powder. This allows for further reduction of paste costs while maintaining high photoelectric conversion efficiency. Extensive experimental verification has shown that the highest photoelectric conversion efficiency is achieved when the mass percentage of micron-sized spherical nickel powder in the silver-nickel paste is between 6% and 20%. The modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. To improve the adhesion between the micron-sized and nano-sized spherical nickel powders during sintering, after mixing, the micron-sized and nano-sized spherical nickel powders are ball-milled using zirconium oxide. The organic modifier is added during the ball milling process to modify the nickel-silver powder, increasing the acetic acid resistance of the prepared silver-nickel paste, reducing the resistivity of the corresponding grid lines, improving the fill factor, reducing the aging risk of damp-heat degradation in the prepared solar cells, and allowing nano-sized spherical silver powder to adhere to the surface of the micron-sized nickel powder, thus achieving fusion of the micron-sized and nano-sized spherical nickel powders. Optionally, the organic modifier includes lauryl ether phosphate. In this embodiment, the modified nickel-silver mixture can be understood as a mixture of large nickel powder particles with small silver powder particles adhering to their surfaces. Exemplarily, this modified nickel-silver mixture can be prepared by ball milling micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The particle size of the nano-sized spherical silver powder differs from that of the micron-sized spherical silver powder and micron-sized spherical nickel powder. The nano-sized spherical silver powder is included because of its small particle size, making it easy to adsorb onto the surface of the micron-sized spherical nickel powder during mixing. The larger contact area between the nano-sized silver powder and the micron-sized spherical nickel powder improves both the conductivity and adhesion of the micron-sized spherical nickel powder. Exemplarily, the particle size range of the micron-sized spherical nickel powder can be 5μm to 6μm, and therefore, the particle size range of the modified nickel-silver mixture can also be 5μm to 6μm. It is understandable that the higher the purity of the micron-sized spherical nickel powder, the better the conductivity of the prepared silver-nickel paste, and consequently, the better the conductivity of the back grid electrode of the prepared N-type crystalline silicon solar cell. This can effectively improve the power utilization rate of the N-type crystalline silicon solar cell and extend its lifespan. For example, the purity of the micron-sized spherical nickel powder can be 99.9% or higher. Similarly, the higher the purity of the nano-sized spherical silver powder, the better the conductivity of the prepared silver-nickel paste, and consequently, the better the conductivity of the back grid electrode of the prepared N-type crystalline silicon solar cell. This can effectively improve the power utilization rate of the N-type crystalline silicon solar cell and extend its lifespan. For example, the purity of the nano-sized spherical silver powder can be 99.9% or higher.

[0026] Glass powder is an inorganic binder that enables the bonding of the modified nickel-silver mixture with micron-sized spherical silver powder. The mass percentage of glass powder in the silver-nickel slurry can be adjusted based on the total amount of the modified nickel-silver mixture and the micron-sized spherical silver powder. The particle size of the glass powder directly affects the flowability of the silver-nickel slurry. Generally, smaller glass powder particles are more easily dispersed in the slurry, thereby improving its flowability and coatability. For example, the particle size range of the glass powder can be 2 μm to 2.2 μm.

[0027] The organic binder is mainly used for dispersing and printing the modified nickel-silver mixture, and for bonding the components before the glass powder is activated. Subsequently, the mass percentage of the organic binder in the silver-nickel paste can be adjusted according to the total amount of the modified nickel-silver mixture and the micron-sized spherical silver powder.

[0028] Organic additives possess excellent weather resistance, corrosion resistance, and high activity, serving as dispersants and diluents. They improve and regulate the performance of the formed silver-nickel paste, maintaining good printing shape. After the silver-nickel paste is printed in the area corresponding to the back grid electrodes of an N-type crystalline silicon solar cell, it contributes to the overall performance improvement of the N-type crystalline silicon solar cell. Furthermore, the stability of the silver-nickel paste is a crucial indicator of its performance, encompassing two aspects: the oxidation resistance of the paste and the dispersibility of the silver powder (or nickel powder). The organic additives may also contain antioxidants to prevent oxidation of the silver-nickel paste and dispersants to prevent the agglomeration of the silver powder (or nickel powder). In organic carriers, antioxidants primarily address the issue of the silver powder's susceptibility to oxidation, while dispersants are needed to disperse the silver powder (or nickel powder) to prevent agglomeration. The types of organic additives can be selected appropriately as needed. Optionally, organic additives include at least one of fatty alcohol ether phosphates, aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, lauryl phosphates, silicone oils, diesters, lauryl phosphate diesters, and a mixture of BYK-115.

[0029] Specifically, each raw material component plays a specific role in the silver-nickel paste. The raw material components are formulated according to their mass percentage in the silver-nickel paste, allowing for adjustments based on the solid content of each component during formulation. For example, in one specific embodiment, the organic additive accounts for 1.5% of the silver-nickel paste by mass, the micron-sized spherical silver powder accounts for 64.5% by mass, the modified nickel-silver mixture accounts for 13.5% by mass (of which, the micron-sized spherical nickel powder accounts for 12% by mass, the nano-sized spherical silver powder accounts for 1% by mass, and the organic modifier accounts for 0.5% by mass), the organic binder accounts for 19% by mass, and the glass powder accounts for 1.5% by mass.

[0030] In the technical solution of this invention embodiment, a modified nickel-silver mixture is used in the silver-nickel paste. In order to better bond the micron-sized spherical nickel powder and the nano-sized spherical silver powder together during the sintering process, after the micron-sized spherical nickel powder and the nano-sized spherical silver powder are mixed, the micron-sized spherical nickel powder and the nano-sized spherical silver powder are milled using a ball mill (zirconia). During the ball milling process, an organic modifier is added to modify the nickel-silver powder, thereby increasing the acetic acid resistance of the prepared silver-nickel paste, reducing the resistivity of the corresponding grid lines formed by the prepared silver-nickel paste, improving the fill factor, reducing the aging risk of damp heat degradation of the prepared battery cell, and also causing the surface of the micron-sized spherical nickel powder to be coated with nano-sized spherical silver powder, thus achieving the fusion of the micron-sized spherical nickel powder and the nano-sized spherical silver powder together. Furthermore, this embodiment provides a low-cost and high-quality silver-nickel paste. Applying this silver-nickel paste to the fabrication process of the back grid electrode of an N-type crystalline silicon solar cell solves the problem of increased production costs due to the high cost of existing pure silver paste. Compared to expensive pure silver paste, using nickel powder to replace a portion of the silver powder in pure silver paste (e.g., a replacement ratio of 6% to 20%) effectively reduces the amount and cost of silver powder used. This low-cost silver-nickel paste can maintain or even improve the high photoelectric conversion efficiency of N-type crystalline silicon solar cells, achieving a long lifespan and maintaining a stable short-circuit current. By controlling the open-circuit voltage, the fill factor can be stabilized, thus ensuring the stability of the photoelectric conversion efficiency of N-type crystalline silicon solar cells. This also reduces the manufacturing cost of N-type crystalline silicon solar cells, achieving cost optimization and thus improving the overall cost-effectiveness of the final N-type crystalline silicon solar cells. This enhances the competitiveness of N-type crystalline silicon solar cells in the industry. Furthermore, the back side of N-type crystalline silicon solar cells has lower requirements for parameters such as light utilization and shading area, which provides a favorable opportunity for the application of silver-nickel paste in the preparation of the back grid electrodes of N-type crystalline silicon solar cells.

[0031] Optionally, the organic adhesive includes a polymer and an organic solvent; wherein the polymer accounts for 6% to 10% of the organic adhesive by mass, and the organic solvent accounts for 90% to 94% of the organic adhesive by mass.

[0032] Specifically, polymers primarily achieve a strong bond between two or more objects through the interaction between their molecular chains and the surfaces of the adhered objects, thereby improving the adhesion and bonding effect of organic adhesives. Organic solvents can adjust the viscosity of organic adhesives to achieve optimal performance and also enable rapid curing, improving production efficiency. For example, an organic adhesive may comprise 8% by weight of a polymer and 92% by weight of an organic solvent. For example, the polymer may comprise ethyl cellulose N50. For example, the polymer may be a polymer with a low residual viscoelastic modulus after sintering. For example, the organic solvent may comprise at least five of the following: terpineol, butylcarbiol, butylcarbiol acetate, tributyl citrate, Span 85, and twelfth alcohol ester. For example, in one specific embodiment, the organic solvent may be composed of five components: terpineol, butylcarbiol, butylcarbiol acetate, tributyl citrate, and Span 85. The terpineol component comprises 10% by mass, the butylcarbiol component comprises 20% by mass, the butylcarbiol acetate component comprises 15% by mass, the tributyl citrate component comprises 15% by mass, and the Span 85 component comprises 40% by mass. Each component in the organic solvent exhibits good solubility and stability. Preparing it in this organic solvent ratio effectively improves the stability of the silver-nickel paste, enabling the prepared silver-nickel paste to be used sustainably.

[0033] Optionally, the glass powder includes Bi₂O₃ (bismuth trioxide), Al₂O₃ (aluminum trioxide), SiO₂ (silicon dioxide), ZnO (zinc oxide), Sb₂O₅ (antimony pentoxide), B₂O₃ (boron trioxide), TeO₃ (tellurium trioxide), and PbO (lead oxide); wherein the mass percentage of Bi₂O₃ in the glass powder is between 10% and 20%; the mass percentage of Al₂O₃ in the glass powder is between 15% and 22%; the mass percentage of SiO₂ in the glass powder is between 10% and 20%; the mass percentage of ZnO in the glass powder is between 12% and 15%; the mass percentage of Sb₂O₅ in the glass powder is between 15% and 20%; the mass percentage of B₂O₃ in the glass powder is between 10% and 20%; the mass percentage of TeO₃ in the glass powder is between 8% and 10%; and the mass percentage of PbO in the glass powder is between 10% and 20%.

[0034] Specifically, the glass powder can be obtained by mixing Bi2O3, Al2O3, SiO2, ZnO, Sb2O5, B2O3, TeO3, and PbO in a certain proportion, melting them at high temperature, and then sintering and pulverizing them. For example, in one specific embodiment, the mass percentage of Bi2O3 in the glass powder is 13%, Al2O3 is 15%, SiO2 is 12%, ZnO is 12%, Sb2O5 is 15%, B2O3 is 13%, TeO3 is 10%, and PbO is 10%.

[0035] Based on the same inventive concept, this invention also provides a method for preparing silver-nickel paste. Figure 1 This is a schematic flowchart of a method for preparing a silver-nickel paste according to an embodiment of the present invention. This method is used to prepare the silver-nickel paste as provided in any one of the embodiments of the present invention, such as... Figure 1 As shown, the preparation method includes: S110 involves mixing micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier to prepare a modified nickel-silver mixture.

[0036] Specifically, the silver-nickel paste in this embodiment can be understood as being prepared by replacing part of the silver powder in pure silver paste with nickel powder. The modified nickel-silver mixture includes micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. To better bond the micron-sized spherical nickel powder and nano-sized spherical silver powder together during sintering, after mixing the micron-sized spherical nickel powder and nano-sized spherical silver powder, the micron-sized spherical nickel powder and nano-sized spherical silver powder are ball-milled using zirconium oxide. During the ball milling process, the organic modifier is added to modify the nickel-silver powder, increasing the acetic acid resistance of the prepared silver-nickel paste, reducing the resistivity of the corresponding grid lines formed by the prepared silver-nickel paste, improving the fill factor, reducing the aging risk of damp heat degradation in the prepared battery cell, and also causing nano-sized spherical silver powder to adhere to the surface of the micron-sized spherical nickel powder, thus achieving the fusion of the micron-sized spherical nickel powder and nano-sized spherical silver powder. Optionally, the organic modifier includes lauryl ether phosphate. In this embodiment, the modified nickel-silver mixture can be understood as a mixture of large nickel powder particles with small silver powder particles attached to their surfaces. Exemplarily, this modified nickel-silver mixture can be prepared by ball milling micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. Furthermore, to improve the adhesion between the nickel and silver powders during sintering, the nickel and silver powders are ball-milled (using zirconia material), causing small silver powder particles to attach to the surfaces of the large nickel powder particles, thus fusing the surfaces of the large nickel powder particles with the small silver powder particles. This reduces the resistivity of the nickel-silver grid lines during subsequent sintering, lowering slurry costs and increasing the fill factor without affecting the photoelectric conversion efficiency of the solar cell, thereby improving the economic benefits for the solar cell company.

[0037] S120. The organic binder and glass powder are mixed and dispersed to obtain a uniformly mixed first powder.

[0038] Specifically, after the organic binder and glass powder are mixed, a disperser can be used to mix and stir them, which can provide a better dispersion effect, avoid the aggregation or sedimentation of the mixed powder, and make the powder mixture more uniform.

[0039] S130. Add micron-sized spherical silver powder and modified nickel-silver mixture to the first powder, and disperse and grind the first powder, micron-sized spherical silver powder and modified nickel-silver mixture to obtain a uniformly mixed second powder.

[0040] Specifically, a mixture of micron-sized spherical silver powder and modified nickel-silver is added to the first powder. A disperser is used to mix and stir the first powder, the micron-sized spherical silver powder and the modified nickel-silver mixture. Then, a grinding device is used to reduce the surface roughness of the mixed powder to obtain a finer secondary powder.

[0041] It should also be noted that S110 is the step of preparing the modified nickel-silver mixture, S120 is the step of preparing the first powder, and S130 is the step of mixing the modified nickel-silver mixture with the first powder. This embodiment only illustrates the order of preparation of S110 and S120, and does not limit it. For example, S110 can be performed first and then S120, or S120 can be performed first and then S110, or S110 and S120 can be performed simultaneously.

[0042] S140. Add organic additives to the second powder and disperse the second powder and organic additives to obtain a uniformly mixed silver-nickel paste.

[0043] Specifically, an organic additive is added to the second powder, and the second powder and the organic additive are further dispersed and mixed at high speed using a disperser to obtain the silver-nickel paste of this application.

[0044] The technical solution in this embodiment of the invention first involves mixing micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier to prepare a modified nickel-silver mixture. Then, an organic binder and glass powder are mixed and dispersed to obtain a uniformly mixed first powder. Next, micron-sized spherical silver powder and the modified nickel-silver mixture are added to the first powder, and the first powder, micron-sized spherical silver powder, and the modified nickel-silver mixture are dispersed and ground to obtain a uniformly mixed second powder. Finally, an organic additive is added to the second powder, and the second powder and the organic additive are dispersed to obtain a uniformly mixed silver-nickel paste. Using the above method, a modified nickel-silver mixture is used in the silver-nickel paste. In order to better bond the micron-sized spherical nickel powder and the nano-sized spherical silver powder together during the sintering process, after the micron-sized spherical nickel powder and the nano-sized spherical silver powder are mixed, the micron-sized spherical nickel powder and the nano-sized spherical silver powder are milled using a ball mill (zirconia). During the ball milling process, an organic modifier is added to modify the nickel-silver powder, thereby increasing the acetic acid resistance of the prepared silver-nickel paste, reducing the resistivity of the corresponding grid lines formed by the prepared silver-nickel paste, improving the fill factor, reducing the aging risk of damp heat degradation of the prepared battery cell, and also causing the surface of the micron-sized spherical nickel powder to be coated with nano-sized spherical silver powder, thus achieving the fusion of the micron-sized spherical nickel powder and the nano-sized spherical silver powder together. Furthermore, this embodiment provides a low-cost and high-quality silver-nickel paste. Applying this silver-nickel paste to the fabrication process of the back grid electrode of an N-type crystalline silicon solar cell solves the problem of increased production costs due to the high cost of existing pure silver paste. Compared to expensive pure silver paste, using nickel powder to replace a portion of the silver powder in pure silver paste (e.g., a replacement ratio of 6% to 20%) effectively reduces the amount and cost of silver powder used. This low-cost silver-nickel paste can maintain or even improve the high photoelectric conversion efficiency of N-type crystalline silicon solar cells, achieving a long lifespan and maintaining a stable short-circuit current. By controlling the open-circuit voltage, the fill factor can be stabilized, thus ensuring the stability of the photoelectric conversion efficiency of N-type crystalline silicon solar cells. This also reduces the manufacturing cost of N-type crystalline silicon solar cells, achieving cost optimization and thus improving the overall cost-effectiveness of the final N-type crystalline silicon solar cells. This enhances the competitiveness of N-type crystalline silicon solar cells in the industry. Furthermore, the back side of N-type crystalline silicon solar cells has lower requirements for parameters such as light utilization and shading area, which provides a favorable opportunity for the application of silver-nickel paste in the preparation of the back grid electrodes of N-type crystalline silicon solar cells.

[0045] Figure 2This is a schematic flowchart of another method for preparing a silver-nickel paste provided in this embodiment of the invention. This embodiment is an optimization based on the above embodiment. Optionally, micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier are mixed to prepare a modified nickel-silver mixture, including: Micron-sized spherical nickel powder, nano-sized spherical silver powder, organic modifier, and alcohol are added together in a ball mill for grinding. The zirconia balls inside the ball mill after grinding were cleaned with pure water, resulting in a turbid liquid. The turbid liquid was evaporated and dried to obtain a solid. The solid material was ground and sieved to obtain a modified nickel-silver mixture.

[0046] For details not covered in this embodiment, please refer to the above embodiments. Figure 2 As shown, the preparation method includes: S210. Micron-sized spherical nickel powder, nano-sized spherical silver powder, organic modifier and alcohol are added to a ball mill for grinding.

[0047] Specifically, the modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The mass percentage of micron-sized spherical nickel powder in the silver-nickel paste is between 6% and 20%; the mass percentage of nano-sized spherical silver powder is between 1% and 2%; and the mass percentage of the organic modifier is between 0.1% and 0.6%. In other words, the mass percentage of micron-sized spherical nickel powder in the modified nickel-silver mixture is approximately between 80% and 95%, and the mass percentage of nano-sized spherical silver powder is approximately between 5% and 20%.

[0048] For example, first weigh 5 parts (or 10 parts) of nano-sized spherical silver powder, add it to 95 parts (or 90 parts) of micron-sized spherical nickel powder for mixing, and then add the mixture to a ball mill. An organic modifier and alcohol are then added. The grinding balls in the ball mill are zirconia balls. Zirconia balls are placed in a volume ratio of 1:3:6, consisting of 12 mm, 6 mm, and 2 mm zirconia balls. The ratio of the modified nickel-silver mixture to the zirconia balls is 2 parts:3 parts, and the organic modifier and alcohol together comprise 5 parts, or the organic modifier and alcohol are ground to a depth of 2 cm above the modified nickel-silver mixture and zirconia balls. Then, start the ball mill for grinding. At a grinding speed of 600-800 rpm, the grinding time is 12-16 hours; at a speed of 800-1000 rpm, the grinding time is 10-12 hours; and at a speed of 400-600 rpm, the grinding time is 18-24 hours.

[0049] S220. The zirconia balls inside the ball mill after grinding are cleaned with pure water to obtain a turbid liquid.

[0050] Here, zirconia balls refer to grinding balls inside the ball mill made of zirconia. Specifically, after grinding, cleaning is performed to obtain a turbid liquid. For example, after grinding, the zirconia balls and their inner walls inside the ball mill can be cleaned to obtain a turbid liquid, which actually contains a suspension of a modified nickel-silver mixture.

[0051] S230. The turbid liquid is evaporated and dried to obtain a solid.

[0052] Specifically, the turbid liquid can be evaporated and dried in an oven at a temperature range of 60℃ to 65℃ for 24 hours until the liquid evaporates and a solid is obtained.

[0053] S240. The solid material is ground and sieved to obtain a modified nickel-silver mixture.

[0054] Specifically, the solid material is ground and sieved through a 600-mesh screen to obtain a powder that is a large nickel powder with small silver particles attached, which is the modified nickel-silver mixture.

[0055] S250. The organic binder and glass powder are mixed and dispersed to obtain a uniformly mixed first powder.

[0056] S260. Add micron-sized spherical silver powder and modified nickel-silver mixture to the first powder, and disperse and grind the first powder, micron-sized spherical silver powder and modified nickel-silver mixture to obtain a uniformly mixed second powder.

[0057] S270. Add organic additives to the second powder and disperse the second powder and organic additives to obtain a uniformly mixed silver-nickel paste.

[0058] Based on the same inventive concept, this invention also provides an N-type crystalline silicon solar cell. This N-type crystalline silicon solar cell includes a back grid electrode, which is fabricated using a silver-nickel paste as provided in any of the embodiments of this invention. Therefore, this N-type crystalline silicon solar cell possesses the beneficial effects corresponding to the silver-nickel paste, which will not be elaborated further here.

[0059] Example 1 In this embodiment, the silver-nickel paste comprises organic additives, micron-sized spherical silver powder, a modified nickel-silver mixture, an organic binder, and glass powder. The modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The components and their weight percentages are as follows: organic additives 1.5%, micron-sized spherical silver powder 64.9%, micron-sized spherical nickel powder 12%, nano-sized spherical silver powder 1%, organic modifier 0.1%, organic binder 19%, and glass powder 1.5%. The organic binder comprises a polymer and an organic solvent, with the following components and their weight percentages: polymer 10%, organic solvent 90%. Furthermore, the glass powder includes Bi2O3, Al2O3, SiO2, ZnO, Sb2O5, B2O3, TeO3, and PbO, wherein the components and their weight percentages are as follows: Bi2O3 10%, Al2O3 12%, SiO2 8%, ZnO 12%, Sb2O5 13%, B2O3 10%, TeO3 20%, and PbO 15%. In addition, the types and compositions of organic additives and organic solvents are not specifically required or limited in this embodiment, and can be selected and set according to actual conditions.

[0060] Preparation of the modified nickel-silver mixture: 10 parts of nano-sized spherical silver powder, 90 parts of micron-sized spherical nickel powder, an organic modifier, and alcohol (exemplarily, the weight ratio of organic modifier to alcohol is 85% alcohol to 15% organic modifier) ​​are added to a ball mill for grinding. First, 10 parts of nano-sized spherical silver powder are weighed and mixed with 90 parts of micron-sized spherical nickel powder, then added to the ball mill, followed by the addition of the organic modifier and alcohol. The grinding balls in the ball mill are zirconia balls. Zirconia balls are placed in a volume ratio of 1:3:6, consisting of 12 mm, 6 mm, and 2 mm zirconia balls. The ratio of the modified nickel-silver mixture to the zirconia balls is 2 parts:3 parts, and the organic modifier and alcohol together comprise 5 parts, or the organic modifier and alcohol are ground together with the silver-nickel mixture and zirconia balls at a depth of 2 cm. Then start the ball mill for grinding. The grinding speed is 400-600 rpm and the grinding time is 18-24 hours.

[0061] After grinding, a turbid liquid is obtained by cleaning. Specifically, after grinding, the zirconia balls inside the ball mill, i.e., their inner walls, are cleaned to obtain a turbid liquid; this turbid liquid actually contains a suspension of a modified nickel-silver mixture.

[0062] The turbid liquid was evaporated and dried to obtain a solid. Specifically, the turbid liquid was evaporated and dried in an oven at 60°C for 24 hours until the liquid evaporated, thus obtaining a solid.

[0063] The solid material is ground and sieved. Specifically, the solid material is ground and sieved through a 600-mesh sieve, and the resulting powder is the modified silver-nickel mixture.

[0064] After preparing the silver-nickel paste, it can be screen-printed onto a 210mm × 210mm N-type crystalline silicon solar cell (e.g., a monocrystalline N-TOPCon silicon wafer) using a 480-mesh screen to form the back grid electrode (i.e., the silver fine grid). The cell is then sintered in a sintering furnace; exemplarily, the peak sintering temperature can be 768°C. After sintering, light injection treatment is required; exemplarily, the light injection temperature can be 538°C, and the light intensity can be 6000 W / m². 2 After light injection, laser-induced enhancement processing is required. For example, the reverse voltage for laser-induced enhancement can be 12V, and the laser power can be 14W. Laser-induced enhancement involves scanning the area corresponding to the back grid electrodes of the N-type crystalline silicon solar cell and performing a laser-induced process after light injection. This induces silver-silicon interdiffusion, significantly reducing contact resistance, increasing the fill factor, and effectively improving the cell efficiency. The N-type crystalline silicon solar cell prepared in this embodiment, after relevant electrical experiments, shows an open-circuit voltage of 0.7376V, a short-circuit current of 17.770A, a fill factor of 85.20%, and a photoelectric conversion efficiency of 25.38%. It is also evident that the photoelectric conversion efficiency of the N-type crystalline silicon solar cell in this embodiment is 0.08% higher than that of the control group, and the cost reduction per cell for this N-type crystalline silicon solar cell is approximately 0.12 yuan. Furthermore, the N-type crystalline silicon solar cell prepared in the embodiments of the present invention was subjected to an acetic acid experiment, which showed that the cell efficiency decayed by 0.8%, which is far lower than the 3% acetic acid decay value of the N-type crystalline silicon solar cell in the control group.

[0065] Example 2 In this embodiment, the silver-nickel paste comprises organic additives, micron-sized spherical silver powder, a modified nickel-silver mixture, an organic binder, and glass powder. The modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The components and their weight percentages are as follows: organic additives 2%, micron-sized spherical silver powder 64.9%, micron-sized spherical nickel powder 15%, nano-sized spherical silver powder 1.5%, organic modifier 0.1%, organic binder 15%, and glass powder 1.5%. The organic binder comprises a polymer and an organic solvent, with the following components and their weight percentages: polymer 10%, organic solvent 90%. Furthermore, the glass powder includes Bi2O3, Al2O3, SiO2, ZnO, Sb2O5, B2O3, TeO3, and PbO, wherein the components and their weight percentages are as follows: Bi2O3 10%, Al2O3 12%, SiO2 8%, ZnO 12%, Sb2O5 13%, B2O3 10%, TeO3 20%, and PbO 15%. In addition, the types and compositions of organic additives and organic solvents are not specifically required or limited in this embodiment, and can be selected and set according to actual conditions.

[0066] Preparation of the modified nickel-silver mixture: 12 parts of nano-sized spherical silver powder, 88 parts of micron-sized spherical nickel powder, an organic modifier, and alcohol (exemplarily, the weight ratio of organic modifier to alcohol is 85% alcohol to 15% organic modifier) ​​are added to a ball mill for grinding. First, 12 parts of nano-sized spherical silver powder are weighed and mixed with 88 parts of micron-sized spherical nickel powder, then added to the ball mill, followed by the addition of the organic modifier and alcohol. The grinding balls in the ball mill are zirconia balls. Zirconia balls are placed in a volume ratio of 1:3:6, consisting of 12 mm zirconia balls, 6 mm zirconia balls, and 2 mm zirconia balls. The ratio of the modified nickel-silver mixture to zirconia balls is 2 parts:3 parts, and the total amount of organic modifier and alcohol is 5 parts, or the organic modifier and alcohol are ground to a depth of 2 cm above the silver-nickel mixture and zirconia balls. Then start the ball mill for grinding. The grinding speed is 400-600 rpm and the grinding time is 18-24 hours.

[0067] After grinding, a turbid liquid is obtained by cleaning. Specifically, after grinding, the zirconia balls inside the ball mill, i.e., their inner walls, are cleaned to obtain a turbid liquid; this turbid liquid actually contains a suspension of a modified nickel-silver mixture.

[0068] The turbid liquid was evaporated and dried to obtain a solid. Specifically, the turbid liquid was evaporated and dried in an oven at 60°C for 24 hours until the liquid evaporated, thus obtaining a solid.

[0069] The solid material is ground and sieved. Specifically, the solid material is ground and sieved through a 600-mesh sieve, and the resulting powder is the modified silver-nickel mixture.

[0070] After preparing the silver-nickel paste, it can be screen-printed onto a 210mm × 210mm N-type crystalline silicon solar cell (e.g., a monocrystalline N-TOPCon silicon wafer) using a 480-mesh screen to form the back grid electrode (i.e., the silver fine grid). The cell is then sintered in a sintering furnace; exemplarily, the peak sintering temperature can be 763℃. After sintering, light injection treatment is required; exemplarily, the light injection temperature can be 536℃, and the light intensity can be 6000 W / m². 2 After light injection, laser-induced enhancement processing is required. For example, the reverse voltage for laser-induced enhancement can be 12V, and the laser power can be 14W. Laser-induced enhancement involves scanning the area corresponding to the back grid electrodes of the N-type crystalline silicon solar cell and performing a laser-induced process after light injection. This induces silver-silicon interdiffusion, significantly reducing contact resistance, increasing the fill factor, and effectively improving the cell efficiency. The N-type crystalline silicon solar cell prepared in this embodiment, after relevant electrical experiments, shows an open-circuit voltage of 0.7387V, a short-circuit current of 17.775A, a fill factor of 85.25%, and a photoelectric conversion efficiency of 25.44%. It is also evident that the photoelectric conversion efficiency of the N-type crystalline silicon solar cell in this embodiment is 0.14% higher than that of the control group, and the cost reduction per cell for this N-type crystalline silicon solar cell is approximately 0.153 yuan. Furthermore, the N-type crystalline silicon solar cell prepared in the embodiments of the present invention was subjected to an acetic acid experiment, which showed that the cell efficiency decayed by 0.7%, which is far lower than the 3% acetic acid decay value of the N-type crystalline silicon solar cell in the control group.

[0071] control group In this embodiment, existing silver paste is used to fabricate the back grid electrode of an N-type crystalline silicon solar cell. The silver paste comprises organic additives, silver powder, organic binder, and glass powder, with the following composition and weight percentage: organic additives 1.5%, silver powder 81.5%, organic binder 15%, and glass powder 2%. The organic binder comprises a polymer and an organic solvent, with the following composition and weight percentage: polymer 10% and organic solvent 90%. The glass powder comprises Bi₂O₃, Al₂O₃, SiO₂, ZnO, Sb₂O₅, B₂O₃, and TeO₃, with the following composition and weight percentage: Bi₂O₃ 10%, Al₂O₃ 12%, SiO₂ 12%, ZnO 15%, Sb₂O₅ 15%, B₂O₃ 15%, and TeO₃ 21%. Furthermore, the types and compositions of the organic additives and organic solvents are not specifically required or limited in this embodiment and can be selected and set according to actual conditions.

[0072] After preparing the silver paste, it can be screen-printed onto a 210mm × 210mm N-type crystalline silicon solar cell (e.g., a monocrystalline N-TOPCon silicon wafer) using a 480-mesh screen to form the back grid electrode (i.e., the silver fine grid). Then, it is sintered in a sintering furnace; exemplarily, the peak sintering temperature can be 765℃. After sintering, light injection treatment is required, followed by laser-induced efficiency enhancement treatment. The N-type crystalline silicon solar cell prepared in this control group, after relevant electrical experiments, showed an open-circuit voltage of 0.7368V, a short-circuit current of 17.65A, a fill factor of 85.60%, and a photoelectric conversion efficiency of 25.30%. Furthermore, the N-type crystalline silicon solar cell prepared in this embodiment of the invention, after undergoing an acetic acid test, showed an efficiency degradation of 3%.

[0073] It should be noted that, compared with the control group, the silver-nickel paste prepared in Examples 1 and 2, when applied to N-type crystalline silicon solar cells, showed a certain degree of improvement in photoelectric conversion efficiency and acetic acid resistance compared to the control group. It is reasonable to believe that with continuous process improvement and adjustments to the mass percentages and combinations of components in the silver-nickel paste, even greater breakthroughs are possible. Similarly, Examples 1 and 2 also showed slightly higher performance than the control group in electrical experimental parameters such as open-circuit voltage, short-circuit current, and fill factor. Moreover, compared to the rarer and more expensive pure silver paste, the nickel powder used in the silver-nickel paste is inexpensive and produced in high quantities, thus significantly reducing costs. Furthermore, the silver-nickel paste also exhibited superior performance compared to pure silver paste in the acetic acid-induced damp heat aging test. The addition of organic modifiers also significantly improved the acetic acid resistance of the prepared solar cells. In the fabrication process of the back grid line electrode of N-type crystalline silicon solar cells, the requirements for light utilization, light transmission area, light shading area, and grid line fabrication precision are relatively low. The silver-nickel paste in this embodiment can replace the existing pure silver paste, effectively reducing the production cost of N-type crystalline silicon solar cells.

[0074] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0075] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A silver-nickel paste, characterized in that, It includes organic additives, micron-sized spherical silver powder, a modified nickel-silver mixture, an organic binder, and glass powder. The modified nickel-silver mixture comprises micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier. The organic additive is present in the silver-nickel paste at a mass percentage between 1.5% and 2%. The mass percentage of the micron-sized spherical silver powder in the silver-nickel paste is between 55% and 65%. The mass percentage of the micron-sized spherical nickel powder in the silver-nickel paste is between 6% and 20%. The mass percentage of the nano-sized spherical silver powder in the silver-nickel paste is between 1% and 2%. The organic modifier is present in the silver-nickel paste at a mass percentage between 0.1% and 0.6%. The organic binder is present in the silver-nickel paste at a mass percentage between 9% and 35%. The glass powder constitutes a mass percentage of 1.5% to 2% in the silver-nickel paste.

2. The silver-nickel paste according to claim 1, characterized in that, The organic modifier includes lauryl ether phosphate.

3. The silver-nickel paste according to claim 1, characterized in that, The organic additives include at least one of fatty alcohol ether phosphates, aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, lauryl phosphates, silicone oil, diesters, lauryl phosphate diesters, and a mixture of BYK-115.

4. The silver-nickel paste according to claim 1, characterized in that, The organic adhesive comprises a polymer and an organic solvent; wherein... The polymer is present in the organic adhesive at a mass percentage between 6% and 10%. The organic solvent in the organic adhesive is between 90% and 94% by mass.

5. The silver-nickel paste according to claim 4, characterized in that, The organic solvent includes at least five of the following: terpineol, butylcarbiol, butylcarbiol acetate, tributyl citrate, Span 85, and ester 12.

6. The silver-nickel paste according to claim 1, characterized in that, The glass powder comprises Bi₂O₃, Al₂O₃, SiO₂, ZnO, Sb₂O₅, B₂O₃, TeO₃, and PbO; wherein, The mass percentage of Bi2O3 in the glass powder is between 10% and 20%. The mass percentage of AL2O3 in the glass powder is between 15% and 22%. The mass percentage of SiO2 in the glass powder is between 10% and 20%. The ZnO in the glass powder is between 12% and 15% by mass; The mass percentage of Sb2O5 in the glass powder is between 15% and 20%. The mass percentage of B2O3 in the glass powder is between 10% and 20%. The mass percentage of TeO3 in the glass powder is between 8% and 10%. The mass percentage of PbO in the glass powder is between 10% and 20%.

7. The silver-nickel paste according to claim 1, characterized in that, The glass powder has a particle size range of 2μm to 2.2μm.

8. A method for preparing a silver-nickel paste, characterized in that, The method for preparing the silver-nickel paste as described in any one of claims 1-7 comprises: Micron-sized spherical nickel powder and nano-sized spherical silver powder are mixed with organic modifiers to prepare modified nickel-silver mixtures; The organic binder and glass powder are mixed and dispersed to obtain a uniformly mixed first powder. Micron-sized spherical silver powder and the modified nickel-silver mixture are added to the first powder, and the first powder, the micron-sized spherical silver powder and the modified nickel-silver mixture are dispersed and ground to obtain a uniformly mixed second powder; An organic additive is added to the second powder, and the second powder and the organic additive are dispersed to obtain a uniformly mixed silver-nickel paste.

9. The method for preparing silver-nickel paste according to claim 8, characterized in that, A modified nickel-silver mixture is prepared by mixing micron-sized spherical nickel powder, nano-sized spherical silver powder, and an organic modifier, comprising: The micron-sized spherical nickel powder, the nano-sized spherical silver powder, the organic modifier, and alcohol are added together into a ball mill for grinding. The zirconia balls inside the ball mill after grinding were cleaned with pure water to obtain a turbid liquid; The turbid liquid was evaporated and dried to obtain a solid. The solid material is ground and sieved to obtain the modified nickel-silver mixture.

10. An N-type crystalline silicon solar cell, characterized in that, It includes a back grid line electrode, which is prepared using a silver-nickel paste as described in any one of claims 1-7.

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