Electrode slurry and solar cell

Abstract

This application discloses an electrode paste and a solar cell, relating to the field of photovoltaic cell technology, to solve the problem of difficulty in controlling the passivation layer during the etching process of solar cells. The electrode paste comprises: silver-coated copper powder, conductive filler, a binder system, a solvent, and additives. The binder system includes a curing resin and a curing agent. The curing resin can undergo a crosslinking reaction with the curing agent at a first temperature, which is lower than the critical oxidation temperature of the silver-coated copper powder. The solar cell includes the electrode paste provided by the above-described technical solution. The electrode paste provided in this application is used to prepare solar cells.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and in particular to an electrode paste and a solar cell. Background Technology

[0002] In the field of solar cell technology, TOPCON cells are currently the mainstream technology, and electrode metallization is a crucial step in cell manufacturing and a significant component of cost. Silver-coated copper technology offers a new path to cost reduction for TOPCON cells while addressing oxidation issues. However, the silver-coated copper paste using a low-temperature curing process struggles to achieve good contact with the TOPCON cell cells, necessitating the addition of a seed layer at the bottom to achieve contact, thus increasing costs. Summary of the Invention

[0003] The purpose of this application is to provide an electrode paste and a solar cell for applying a low-temperature conductive paste to a composite cell, thereby solving the problems of slow curing speed and high resistivity of existing low-temperature conductive pastes.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] An electrode paste includes: silver-coated copper powder, conductive filler, binder system, solvent, and additives. The binder system includes a curing resin and a curing agent. The curing resin can undergo a crosslinking reaction with the curing agent at a first temperature, which is lower than the critical oxidation temperature of the silver-coated copper powder.

[0006] Compared with existing technologies, the electrode slurry provided in this application uses silver-coated copper powder as the main conductive framework. Its single-crystal structure and dense silver coating not only endow the powder with excellent oxidation resistance but also achieve high packing density through the combination of different particle sizes, reducing the contact resistance between particles. In the initial state after slurry preparation, the silver-coated copper powder particles are dispersed in the solvent with a core-shell structure of copper as the core and silver as the shell, while conductive filler particles fill the interstitial areas between the silver-coated copper powder particles. At this time, the entire system is in a physically dispersed state and has not yet formed a continuous conductive path.

[0007] When the electrode paste is heated to a temperature below the critical oxidation temperature of the silver-coated copper powder, the curing agent de-encapsulates and releases active groups, which then undergo a cross-linking reaction with the curing resin to form a three-dimensional polymer network. Since this reaction occurs within a temperature window before the silver-coated copper powder undergoes significant oxidation, the construction of the polymer network is unaffected by metal oxide impurities. Furthermore, because the temperature remains consistently below the critical oxidation temperature of the silver-coated copper powder, the silver shell remains dense and intact, and the copper core is effectively isolated, preventing contact with oxygen. This indicates that in the initial stage of conductive network formation, the particle surface is metallic silver, rather than high-resistivity copper oxide or cuprous oxide. The metal contact surface provides a low-barrier channel for electron transport. As the cross-linking reaction proceeds, the polymer network gradually shrinks, tightly encapsulating and pulling the silver-coated copper powder and conductive filler particles closer together, creating physical contact points between the particles. Near the completion of the curing reaction, the polymer network is fully cured and shaped, with the silver-coated copper powder and conductive filler firmly anchored within the three-dimensional framework, forming a stable conductive percolation network.

[0008] Within the aforementioned conductive permeation network, the contact between conductive particles is a direct metal-to-metal contact, rather than an indirect contact through an oxide layer or polymer thin layer. Therefore, the interfacial resistance is extremely low. Furthermore, while the polymer network acts as a bond, it also further enhances the compaction force between particles through shrinkage stress, thereby further reducing the contact resistance. In addition, since the curing process is completed before oxidation occurs, the core-shell structure of the silver-coated copper powder is completely preserved, and the high conductivity of the copper core is fully utilized, resulting in high overall conductivity.

[0009] In summary, this application controls the curing reaction temperature below the critical oxidation temperature, thereby constructing a conductive network before the silver-coated copper powder oxidizes, thus avoiding oxidation and ensuring that the conductive particles contact each other through the metal interface. The polymer network anchors the conductive framework in an optimal manner, ultimately forming a low-resistance, high-reliability electrode microstructure.

[0010] This application also provides a solar cell, wherein the electrodes of the solar cell comprise the electrode paste described above or any of the possible electrode pastes described above.

[0011] Compared with the prior art, the beneficial effects of the solar cell provided in this application are the same as those of the electrode paste described in the above technical solutions, and will not be repeated here. Attached Figure Description

[0012] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram showing the morphology of the electrode paste provided in the embodiments of this application is shown; Figure 2 A schematic diagram showing the morphology of the silver-coated copper powder provided in an embodiment of this application is shown; Figure 3 A schematic diagram showing the morphology of the nano-silver powder provided in the embodiments of this application is shown. Detailed Implementation

[0013] The embodiments of this application will be described below. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0014] In the context of this application, when a layer / element is referred to as being "on top of" another layer / element, the layer / element can be directly on top of the other layer / element, or there can be an intermediate layer / element between them. Furthermore, if a layer / element is "on top of" another layer / element in one orientation, then when the orientation is reversed, the layer / element can be "below" the other layer / element. To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0015] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0016] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0017] In the field of solar cell technology, TOPCON cells are currently the mainstream technology, and electrode metallization is a key step in cell manufacturing and a significant part of the cost. Since paste costs account for 60%-70% of the total cost of electrode metallization, the potential for cost reduction in TOPCON cell technology is limited by the continued rise in silver prices and the scarcity of silver resources.

[0018] Copper is considered the best alternative material due to its resistivity being close to that of silver, but its easy oxidation results in near-insulation after oxidation, posing a major technical challenge. Silver-coated copper technology, by coating a copper core with a silver layer, solves the oxidation problem and provides a new path for industrialization. This technology has been widely applied in heterojunction solar cells, but faces different challenges in TOPCON cells. In heterojunction cells, grid metallization can be achieved simply by printing silver-coated copper paste onto a TCO film and curing it at low temperatures; however, in TOPCON cells, the low-temperature cured silver-coated copper paste struggles to form good contact with the cell, requiring a seed layer at the bottom to achieve ohmic contact before layering the silver-coated copper paste to improve efficiency.

[0019] In current technology, the silver-coated copper paste for TOPCON batteries is mostly designed based on the paste used in heterojunction batteries. It generally suffers from problems such as low curing temperature, slow curing speed, high silver content, large printing linewidth, and high resistivity after curing. It cannot meet the process requirements of TOPCON batteries for fast printing, fast curing, low silver consumption, and high conductivity.

[0020] To overcome the above problems, an exemplary embodiment of this application provides an electrode paste for preparing solar cells. Figure 1 A schematic diagram showing the morphology of the electrode paste provided in an embodiment of this application is illustrated. For example... Figure 1 As shown, the electrode paste includes silver-coated copper powder, conductive filler, binder system, solvent and additives. Through the synergistic effect of each component, it achieves rapid low-temperature curing, low resistivity, low silver content and excellent screen printing performance, meeting the high-efficiency and low-cost requirements of composite batteries for electrode paste.

[0021] Figure 2 A schematic diagram illustrating the morphology of the silver-coated copper powder provided in an embodiment of this application is shown. For example... Figure 2 As shown, the aforementioned silver-coated copper powder can be a single-crystal silver-coated copper powder, with a uniform silver layer coated on its surface, exhibiting high density and good oxidation resistance. In one example, the silver content of the single-crystal silver-coated copper powder can be 3%-15%, the particle size D50 of the single-crystal silver-coated copper powder is 1μm-6μm, and D100 < 10μm. It is understood that the silver-coated copper powder here can be a mixture of one or more silver-coated copper powders with different particle sizes and different silver contents that meet the aforementioned requirements, in order to optimize the packing density and conductive network.

[0022] The aforementioned bonding system may include a curing resin and a curing agent. The curing resin and the curing agent can undergo a cross-linking reaction at a first temperature, which is lower than the critical oxidation temperature of the silver-coated copper powder. That is, the curing resin and the curing agent can cure rapidly at low temperatures, forming a dense and stable conductive network, thereby effectively inhibiting the oxidation of the silver-coated copper powder.

[0023] As can be seen, in the electrode slurry provided in this application embodiment, by using silver-coated copper powder as the main conductive framework, its single-crystal structure and dense silver coating not only endow the powder with good oxidation resistance, but also achieve high packing density through the combination of different particle sizes, reducing the contact resistance between particles. In the initial state after the slurry preparation is completed, the silver-coated copper powder particles are dispersed in the solvent with a core-shell structure of copper as the core and silver as the shell, while the conductive filler particles fill the interstitial areas between the silver-coated copper powder particles. At this time, the entire system is in a physically dispersed state and has not yet formed a continuous conductive path.

[0024] When the electrode paste is heated to a temperature below the critical oxidation temperature of the silver-coated copper powder, the curing agent de-encapsulates and releases active groups, which then undergo a cross-linking reaction with the curing resin to form a three-dimensional polymer network. Since this reaction occurs within a temperature window before the silver-coated copper powder undergoes significant oxidation, the construction of the polymer network is unaffected by metal oxide impurities. Furthermore, because the temperature remains consistently below the critical oxidation temperature of the silver-coated copper powder, the silver shell remains dense and intact, and the copper core is effectively isolated, preventing contact with oxygen. This indicates that in the initial stage of conductive network formation, the particle surface is metallic silver, rather than high-resistivity copper oxide or cuprous oxide. The metal contact surface provides a low-barrier channel for electron transport. As the cross-linking reaction proceeds, the polymer network gradually shrinks, tightly encapsulating and pulling the silver-coated copper powder and conductive filler particles closer together, creating physical contact points between the particles. Near the completion of the curing reaction, the polymer network is fully cured and shaped, with the silver-coated copper powder and conductive filler firmly anchored within the three-dimensional framework, forming a stable conductive percolation network.

[0025] Within the aforementioned conductive permeation network, the contact between conductive particles is a direct metal-to-metal contact, rather than an indirect contact through an oxide layer or polymer thin layer. Therefore, the interfacial resistance is extremely low. Furthermore, while the polymer network acts as a bond, it also further enhances the compaction force between particles through shrinkage stress, thereby further reducing the contact resistance. In addition, since the curing process is completed before oxidation occurs, the core-shell structure of the silver-coated copper powder is completely preserved, and the high conductivity of the copper core is fully utilized, resulting in high overall conductivity.

[0026] In summary, this application controls the curing reaction temperature below the critical oxidation temperature, thereby constructing a conductive network before the silver-coated copper powder oxidizes, thus avoiding oxidation and ensuring that the conductive particles contact each other through the metal interface. The polymer network anchors the conductive framework in an optimal manner, ultimately forming a low-resistance, high-reliability electrode microstructure.

[0027] In some embodiments, the electrode paste may include, by weight parts: 60-88 parts of silver-coated copper powder, 5-35 parts of conductive filler, 0.5-2 parts of curing resin, 0.5-2 parts of curing agent, 4-10 parts of solvent and 0-7.5 parts of additives.

[0028] For example, the electrode paste may include 60 parts, 70 parts, 80 parts, or 88 parts of silver-coated copper powder, etc., and is not limited thereto. The electrode paste may include 5 parts, 15 parts, 25 parts, or 35 parts of conductive filler, etc., and is not limited thereto. The electrode paste may include 0.5 parts, 1 part, 1.5 parts, or 2 parts of curing resin, etc., and is not limited thereto. The electrode paste may include 0.5 parts, 1 part, 1.5 parts, or 2 parts of curing agent, etc., and is not limited thereto. The electrode paste may include 4 parts, 6 parts, 8 parts, or 10 parts of solvent, etc., and is not limited thereto. The electrode paste may not include additives, or may include 0.5 parts, 2.5 parts, 5 parts, or 7.5 parts of additives, etc., and is not limited thereto.

[0029] In some embodiments, the curing resin may include a first resin and a second resin. The first resin has a first functional group capable of crosslinking with the curing agent, and the second resin has a second functional group capable of crosslinking with the curing agent. By using the first resin and the second resin, the first resin and the curing agent can synergistically crosslink, thereby constructing a polymer network with higher crosslinking density and better mechanical properties. This further enhances the adhesion and cohesion of the cured electrode paste and reduces resistivity while achieving rapid curing at low temperatures. It is understood that the first functional group and the second functional group can be the same or different, as long as they can undergo crosslinking reactions with the active groups in the curing agent. By selecting functional groups with different reactivity, the rate of the curing reaction and the structure of the crosslinked network can be controlled.

[0030] In some embodiments, the first functional group and the second functional group are each independently selected from one or more of epoxy, hydroxyl, and carboxyl groups. For example, the first functional group and the second functional group can be epoxy, hydroxyl, and carboxyl groups, or epoxy, hydroxyl, and carboxyl groups.

[0031] In one example, the first functional group can be an epoxy group, and the second functional group can be a hydroxyl group. In this case, the first resin can be an epoxy resin containing multiple epoxy groups in its molecular chain; the second resin can be a hydroxyl acrylic resin containing multiple hydroxyl groups in its molecular chain. The epoxy groups react with isocyanate groups to form an oxazolidinone structure, and the hydroxyl groups react with isocyanate groups to form a urethane structure. The two reactions occur simultaneously, forming an interpenetrating or semi-interpenetrating polymer network, which significantly improves the crosslinking density and mechanical properties. In addition, the epoxy groups can undergo ring-opening self-polymerization under the action of an accelerator, further enhancing the network strength.

[0032] The epoxy resin mentioned above can be one or more epoxy resins with an epoxy equivalent of 100-200, for example, the epoxy equivalent of the epoxy resin can be 100, 150, 170 or 200, etc., and is not limited thereto. The epoxy resin can include multiple epoxy resins with different epoxy equivalents that meet the above range requirements.

[0033] The aforementioned hydroxy acrylic resin is one or more hydroxy acrylic resins with a hydroxyl value between 50 mg KOH / g and 80 mg KOH / g, for example, the hydroxy acrylic resin has a hydroxyl value of 50 mg KOH / g, 70 mg KOH / g, or 80 mg KOH / g, etc., and is not limited thereto. The hydroxy acrylic resin may include multiple hydroxy acrylic resins with different hydroxyl values ​​that meet the above range requirements.

[0034] In another example, the first functional group can be a hydroxyl group and the second functional group can be a carboxyl group; or the first functional group can be an amino group and the second functional group can be an epoxy group, etc. As long as both functional groups can react with the curing agent, a dual crosslinking effect can be achieved.

[0035] In some embodiments, the mass ratio of the first resin and the second resin can be adjusted according to actual conditions. For example, the mass ratio of the first resin and the second resin can be 1:0.5 to 1:8. In one example, the mass ratio can be 1:0.5, 1:1, 1:5, 1:7, or 1:8, etc., and is not limited thereto.

[0036] In the embodiments of this application, the specific types of the first resin and the second resin are not limited to the examples above. Any resin containing functional groups that can react with the curing agent can be used, such as phenolic resin, polyester resin, polyurethane resin, etc., as long as the functional group requirements are met and it can react with the curing agent at the first temperature.

[0037] In some embodiments, the curing agent can be a blocked curing agent, and the deblocking temperature of the blocked curing agent is lower than the critical oxidation temperature of the silver-coated copper powder. It is understood that the critical oxidation temperature of the silver-coated copper powder involved in the embodiments of this application can be determined based on parameters such as the silver layer thickness and density, and is not limited here. Here, a blocked curing agent refers to a curing agent that allows the active groups of an active curing agent to undergo a reversible reaction under certain conditions, forming an adduct that is stable at room temperature. This adduct does not exhibit reactivity at room temperature, thus giving the slurry good storage stability. When heated to the deblocking temperature, the chemical bond between the blocker and the curing agent breaks, releasing the reactive curing agent, which then undergoes a crosslinking reaction with the cured resin.

[0038] In this embodiment, the desealing temperature of the sealed curing agent is designed to be lower than the critical oxidation temperature of the silver-coated copper powder. When the electrode slurry is heated, the curing agent first deseales at a lower temperature, releasing active groups and initiating the crosslinking reaction of the cured resin. At this point, the temperature has not yet reached the critical point where the silver-coated copper powder undergoes significant oxidation, so the silver shell layer of the silver-coated copper powder remains intact, and the copper core is not oxidized. As the crosslinking reaction proceeds, a polymer network gradually forms and fixes the conductive particles. The entire conductive network is completed before the silver-coated copper powder oxidizes, thus ensuring that the conductive particles are in contact with each other on a clean metal surface, avoiding an increase in contact resistance caused by the oxide layer.

[0039] In one specific embodiment, the curing agent is a blocked isocyanate curing agent. The active ingredient of this blocked isocyanate curing agent can be a polyisocyanate, which blocks the isocyanate groups. At the deblocking temperature, the blocking agent detaches, releasing the isocyanate groups, which then undergo a crosslinking reaction with the active functional groups in the cured resin to generate the aforementioned urethane, urea, or oxazolidinone structures.

[0040] As a specific implementation method, the unsealing temperature of the above-mentioned curing agent can be between 80℃ and 150℃. For example, the unsealing temperature can be 80℃, 120℃, or 150℃, etc., and is not limited to this. By selecting an unsealing temperature that meets the above temperature range requirements, it is possible to avoid the slurry slowly unsealing during storage or transportation due to excessively low temperatures, which would affect storage stability; at the same time, it is also possible to avoid the temperature being too high, exceeding the critical oxidation temperature of the silver-coated copper powder, which would result in the loss of the protective effect on the silver-coated copper powder. It is understood that the specific value of the unsealing temperature can be selected according to the actual required curing temperature, storage stability requirements, and characteristics of the resin system, etc., and is not limited here.

[0041] In some embodiments, the bonding system further includes 0-0.5 parts by weight of a curing accelerator, which is one or more of imidazole curing accelerators, substituted urea curing accelerators, boron trifluoride complexes, hexafluoroantimonates, and phenolic accelerators. By using a curing accelerator to further optimize the curing process window, faster and more complete curing is achieved while ensuring that the first temperature is below the critical oxidation temperature of the silver-coated copper powder, thereby improving production efficiency and the performance of the cured film.

[0042] In one example, the above-mentioned bonding system may include 0 parts, 0.2 parts, or 0.5 parts of curing accelerator by weight, and is not limited thereto. For cases where the curing rate requirement is not high or the resin / curing agent system itself has high reactivity, the above-mentioned bonding system may not require the addition of a curing accelerator, relying solely on the reactivity of the curing resin and curing agent to complete curing at a set first temperature. Simultaneously, by selecting a curing accelerator within the above-mentioned range, it is possible to avoid excessively vigorous curing reactions due to excessive accelerator addition, which could generate a large amount of reaction heat, leading to localized overheating or excessive stress within the cured film. Furthermore, an excessively fast reaction rate may even affect the orderly arrangement of conductive particles, resulting in increased resistivity or decreased adhesion. In addition, excessive curing accelerator residue in the cured film may adversely affect the long-term stability of the electrode. Therefore, controlling the content of the curing accelerator within the range of 0-0.5 parts can accelerate curing while avoiding the aforementioned problems.

[0043] In another example, the aforementioned curing accelerator may be an imidazole curing accelerator, a substituted urea curing accelerator, a boron trifluoride complex, a hexafluoroantimonate, or a phenolic accelerator, or a combination of imidazole curing accelerators, substituted urea curing accelerators, boron trifluoride complexes, hexafluoroantimonates, and phenolic accelerators, and is not limited thereto.

[0044] In some embodiments, the electrode slurry further includes 0-0.4 parts by weight of a polymeric resin, wherein the polymeric resin is one or more selected from ethyl cellulose, PVB resin, and cellulose acetate butyrate. This polymeric resin does not participate in the curing crosslinking reaction but exists in the slurry system in a physically dispersed form. Therefore, during the curing process, a continuous polymer backbone is formed as the solvent evaporates, or it can be embedded in the crosslinking network as a flexible segment after curing, thereby improving the mechanical and processing properties of the product.

[0045] In one example, the electrode paste, by weight, may include 0 parts, 0.2 parts, or 0.4 parts of polymeric resin, etc., and is not limited thereto. For applications where film flexibility or printability requirements are not high, the film-forming and adhesive properties of the cured resin itself are sufficient to meet the mechanical performance requirements of the electrode. In this case, polymeric resin may not be added to the electrode paste. Simultaneously, by selecting polymeric resins within the aforementioned range, excessively high paste viscosity due to excessive polymeric resin addition can be avoided, which would affect printability and leveling. Furthermore, excessive uncrosslinked polymeric resin remaining in the cured film may act as an insulating phase, hindering contact between conductive particles and leading to increased resistivity. Therefore, controlling the polymeric resin content within the range of 0-0.4 parts can improve the paste processing performance and film mechanical properties while avoiding negative impacts on electrical properties.

[0046] In another example, the aforementioned polymeric resin can be ethyl cellulose, PVB resin, cellulose acetate butyrate, or a combination of ethyl cellulose, PVB resin, and cellulose acetate butyrate, and is not limited thereto. It should be noted that the specific polymeric resin material can be selected to match the solvent system to ensure complete dissolution and uniform dispersion in the slurry.

[0047] In some embodiments, Figure 3 A schematic diagram illustrating the morphology of the nano-silver powder provided in an embodiment of this application is shown. Figure 3 As shown, the conductive filler comprises 5 to 30 parts by weight of nano-silver powder. For example, the conductive filler may include 5, 15, 25, or 30 parts of nano-silver powder, and is not limited to these. By selecting nano-silver powder that meets the above requirements, it avoids the problem that when the content of nano-silver powder is too low, its volume fraction in the paste is too low, making it difficult to form effective conductive bridges between the silver-coated copper powder particles, resulting in a discontinuous conductive network and high resistivity of the cured film, failing to meet the low resistance requirements of solar cell electrodes. At the same time, it avoids the problem that a high content of nano-silver powder increases the raw material cost of the paste, reduces fluidity, affects printing accuracy and line quality, and increases the risk of cracking or peeling.

[0048] In some embodiments, the aforementioned silver nanoparticles include one or more of silver nanoparticles with a particle size of 100 nm to 500 nm. For example, the silver nanoparticles may include silver nanoparticles with a particle size of 100 nm, 150 nm, 500 nm, and a mixture of silver nanoparticles with particle sizes of 100 nm, 200 nm, and 500 nm. By selecting silver nanoparticles that meet the above particle size requirements, a silver nanoparticle with a suitable specific surface area is provided, which can achieve good dispersion stability under suitable dispersant and process conditions, avoiding agglomeration. Furthermore, silver nanoparticles within this particle size range have moderate sintering activity, capable of surface diffusion and sintering at the curing temperature, forming sintering necks between particles, but without excessively rapid sintering or abnormal growth. In addition, silver nanoparticles within this particle size range can effectively fill the gaps between silver-coated copper powder particles, forming a conductive filler system with a multi-level particle size distribution, increasing the packing density and the number of conductive pathways.

[0049] In some embodiments, the surface of the aforementioned silver nanoparticles is coated with a coating agent. By coating the surface of the silver nanoparticles, a steric hindrance or electrostatic repulsion layer is formed, thereby inhibiting particle aggregation and improving dispersion stability in solvents. The coating agent can be selected from one or more of lauric acid, gallic acid, capric acid, polypropylene glycol, polyvinyl alcohol, oleylamine, and triethanolamine. For example, the coating agent can be a combination of lauric acid, gallic acid, capric acid, polypropylene glycol, polyvinyl alcohol, oleylamine, triethanolamine, or a combination of these, and is not limited thereto.

[0050] In some embodiments, the conductive filler further includes 0 to 5 parts by weight of organic silver salt, for example, it may include 0 parts, 2 parts, and 5 parts of organic silver salt, etc., and is not limited thereto. By adding organic silver salt, the organic silver salt undergoes thermal decomposition during heating, releasing metallic silver, thereby generating conductive silver particles in situ to improve conductivity. Moreover, the silver particles generated by the decomposition of organic silver salt are finer than nano-silver powder, which can fill the gaps between nano-silver powder to form a conductive network with a multi-level particle size distribution, further increasing the packing density and the number of conductive pathways.

[0051] In one example, for applications where conductivity requirements are not extremely stringent or cost control is a primary concern, the conductive filler may not include organic silver salts. Instead, it may rely solely on metallic conductive fillers such as silver-coated copper powder and nano-silver powder to construct the conductive network. Because the silver particles produced by the thermal decomposition of organic silver salts are small and have a large specific surface area, selecting organic silver salts that meet the aforementioned requirements can prevent excessive addition of organic silver salts, which could lead to an overly loose or unevenly distributed conductive network. This improves the long-term stability of the electrode and reduces the cost of the slurry.

[0052] In one example, the aforementioned organic silver salt can be one or more of silver acetate, silver oxalate, silver maronate, silver malonate, and silver lactate. For example, it can be a combination of silver acetate, silver oxalate, silver maronate, silver malonate, silver lactate, and silver acetate, silver oxalate, silver maronate, silver malonate, and silver lactate, and is not limited thereto.

[0053] In some embodiments, the additives described above may include one or more of thixotropic agents, reactive diluents, coupling agents, dispersants, and leveling agents. For example, the additives may include, but are not limited to, thixotropic agents, reactive diluents, coupling agents, dispersants, leveling agents, and combinations thereof.

[0054] In some embodiments, the additive, by weight parts, includes 0-0.5 parts of a thixotropic agent, 0-5 parts of an reactive diluent, 0-0.5 parts of a coupling agent, 0-0.5 parts of a dispersant, and 0-0.5 parts of a leveling agent. For example, the additive may include 0 parts of a thixotropic agent, 0.2 parts of a thixotropic agent, and 0.5 parts of a thixotropic agent, etc., and is not limited thereto. The additive may include 0 parts of an reactive diluent, 0.2 parts of an reactive diluent, and 0.5 parts of an reactive diluent, etc., and is not limited thereto. The additive may include 0 parts of a coupling agent, 0.2 parts of a coupling agent, and 0.5 parts of a coupling agent, etc., and is not limited thereto. The additive may include 0 parts of a dispersant, 0.2 parts of a dispersant, and 0.5 parts of a dispersant, etc., and is not limited thereto. The additive may include 0 parts of a leveling agent, 0.2 parts of a leveling agent, and 0.5 parts of a leveling agent, etc., and is not limited thereto.

[0055] In some embodiments, the thixotropic agent is one or more of polyamide wax, polyurea, hydrogenated castor oil, and oleogel. For example, the thixotropic agent can be, but is not limited to, a combination of polyamide wax, polyurea, hydrogenated castor oil, oleogel, and polyamide wax, polyurea, hydrogenated castor oil, and oleogel, to provide thixotropy and prevent line collapse after printing.

[0056] In some embodiments, the above-mentioned reactive diluent may be one or more of monofunctional or polyfunctional glycidyl ethers, glycidyl esters, or acrylic reactive diluents; for example, the reactive diluent may be monofunctional or polyfunctional glycidyl ethers, glycidyl esters, acrylic reactive diluents, or combinations thereof, and is not limited thereto, in order to reduce the viscosity of the slurry, improve its fluidity, and participate in the curing reaction.

[0057] In some embodiments, the coupling agent may be one or more of aminosilane coupling agents, phthalate coupling agents, and aluminate coupling agents; for example, the coupling agent may be a combination of aminosilane coupling agents, phthalate coupling agents, aluminate coupling agents, and aminosilane coupling agents, phthalate coupling agents, and aluminate coupling agents, etc., and is not limited thereto, in order to enhance the interfacial bonding between the silver-coated copper powder and the resin matrix.

[0058] In some embodiments, the dispersant may be one or more of phosphate esters, acrylates, ethylene oxide types, and fatty acids; for example, the dispersant may be phosphate esters, acrylates, ethylene oxide types, fatty acids, or a combination of phosphate esters, acrylates, ethylene oxide types, and fatty acids, etc., and is not limited thereto, to promote uniform dispersion of solid particles.

[0059] In some embodiments, the leveling agent described above may be one or more of acrylates and silicones. For example, the leveling agent may be an acrylate, a silicone, or a combination of acrylates and silicones, etc., and is not limited thereto, to improve the leveling properties of the printed surface and eliminate screen marks.

[0060] In some embodiments, the solvent may include one or more of dipropylene glycol methyl ether, benzyl alcohol, propylene glycol phenyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl ether acetate, 3-methoxy-3-methylbutanol, alcohol ester dodecyl, diethylene glycol butyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, and isooctanol. For example, the solvent may be a combination of dipropylene glycol methyl ether, benzyl alcohol, propylene glycol phenyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl ether acetate, 3-methoxy-3-methylbutanol, alcohol ester dodecyl, diethylene glycol butyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, and isooctanol, and is not limited thereto. In one example, a polymeric resin may also be added to the solvent, such as one or more of ethyl cellulose, PVB resin, and cellulose acetate butyrate, to adjust the rheological properties and printability of the slurry.

[0061] This application also provides a solar cell whose electrodes include the aforementioned electrode paste. In this embodiment, the electrodes of the solar cell are manufactured by applying the electrode paste from the foregoing embodiments of this application to the surface of a cell substrate and then performing a curing or sintering process. Because the electrode paste employs rapid low-temperature curing characteristics, low resistivity, low silver content, and excellent printability, this solar cell can significantly reduce electrode manufacturing costs and improve electrode reliability and durability while maintaining high photoelectric conversion efficiency.

[0062] It should be understood that the solar cells involved in this application may be PERC (Passivated Emitter and Rear Cell) solar cells, HJT (Hereto-junction with Intrinsic Thin-layer) solar cells, and TOPCON (Thin Oxide Passivated Contact) solar cells, etc., and are not limited thereto.

[0063] Compared with the prior art, the beneficial effects of the solar cell provided in this application embodiment are the same as those of the electrode paste described above, and will not be repeated here.

[0064] The present application is further illustrated below by way of embodiments, but these embodiments are not intended to limit the scope of the present application. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or as selected according to the product manual. It should be noted that the exemplary embodiments of this application use the fabrication of a fine grid for a TOPCON solar cell using silver-aluminum paste as an example.

[0065] Example 1 In this embodiment, the silver content of the silver-coated copper powder is 3%, and the particle size D50 is 1 μm; the polymer resin is PVB resin; the thixotropic agent is polyamide wax; the solvent is a mixture of dipropylene glycol methyl ether and dodecyl alcohol ester; the dispersant is a phosphate ester; the first resin is epoxy resin; the second resin is hydroxyl acrylic resin; the curing agent is a blocked isocyanate curing agent; the curing accelerator is an imidazole curing accelerator; the surface of the nano silver powder is coated with lauric acid; the coupling agent is a phthalate coupling agent; and the leveling agent is an acrylate leveling agent.

[0066] Step 1: Preparation of organic carriers By mass, 18 parts of PVB resin and 2 parts of polyamide wax were added to 80 parts of a mixed solvent of dipropylene glycol methyl ether and 12-ol ester in a mass ratio of 1:1. The mixture was stirred and dissolved at 60℃-70℃. After stirring for 2 hours, the mixture was filtered while hot and cooled to obtain an organic carrier (in which the content of PVB resin was 18%, the content of polyamide wax was 2%, and the content of solvent was 80%).

[0067] Step 2: Preparation of electrode paste By mass, 20 parts of 300nm silver nanoparticles, 2 parts of the organic carrier prepared above, 1 part of epoxy resin with an epoxy equivalent of 120, 1 part of hydroxyl acrylic resin with a hydroxyl value of 60, 1 part of blocked isocyanate curing agent, 0.1 part of imidazole curing accelerator, 0.3 parts of phosphate ester dispersant, 0.3 parts of phthalate coupling agent, and 0.3 parts of acrylate leveling agent were mixed and stirred evenly. Then, 72 parts of silver-coated copper powder with a silver content of 15% and 4 parts of diethylene glycol butyl ether solvent were added. After centrifugation and stirring, the mixture was then ground on a three-roll mill. After 5-7 rolling cycles, the fineness was tested. If the fineness was less than 10μm, the dispersion was considered complete. After filtration, a low-temperature silver-coated copper paste with good performance was obtained. The performance test results are shown in Table 1.

[0068] Example 2 In this embodiment, the silver content of the silver-coated copper powder is 12%, the particle size D50 is 2μm, and the rest is the same as in Example 1.

[0069] The preparation methods of the organic carrier and electrode paste in this embodiment are the same as those in Example 1. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0070] Example 3 In this embodiment, the silver content of the silver-coated copper powder is 10%, the particle size D50 is 5μm, and the rest is the same as in Example 1.

[0071] The preparation methods of the organic carrier and electrode paste in this embodiment are the same as those in Example 1. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0072] Example 4 The silver content of the silver-coated copper powder used in this embodiment is 8%, the particle size D50 is 6μm, and the rest is the same as in Example 1.

[0073] The preparation methods of the organic carrier and electrode paste in this embodiment are the same as those in Example 1. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0074] Example 5 Unlike Example 2, the electrode paste preparation method of this example adds 1.5 parts of epoxy resin with an epoxy equivalent of 120 and 0.5 parts of hydroxyl acrylic resin with a hydroxyl value of 60 by mass. The performance test results of the low-temperature silver-coated copper paste prepared are shown in Table 1.

[0075] Example 6 Unlike Example 2, the electrode paste preparation method of this example adds 0.6 parts of epoxy resin with an epoxy equivalent of 120 and 1.4 parts of hydroxyl acrylic resin with a hydroxyl value of 60 by mass. The performance test results of the low-temperature silver-coated copper paste prepared are shown in Table 1.

[0076] Example 7 Unlike Example 2, the electrode paste preparation method of this example adds 0.4 parts of epoxy resin with an epoxy equivalent of 120 and 1.6 parts of hydroxyl acrylic resin with a hydroxyl value of 60 by mass. The performance test results of the low-temperature silver-coated copper paste prepared are shown in Table 1.

[0077] Example 8 Unlike Example 2, in this example, by mass fraction, 5 parts of 300nm silver nanoparticles were added to the preparation method of the electrode paste, and the amount of silver-coated copper powder was adjusted to 60 parts. The rest was the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0078] Example 9 Unlike Example 2, in this example, by mass fraction, 30 parts of 300nm silver nanoparticles were added to the preparation method of the electrode paste, and the amount of silver-coated copper powder was adjusted to 66 parts. The rest was the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0079] Example 10 Unlike Example 2, this example adds 0.25 parts by weight of epoxy resin with an epoxy equivalent of 120 and 0.25 parts by weight of hydroxyl acrylic resin with a hydroxyl value of 60 to the electrode paste preparation method. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0080] Example 11 Unlike Example 2, this example adds 1 part epoxy resin with an epoxy equivalent of 120 and 1 part hydroxyl acrylic resin with a hydroxyl value of 60 to the electrode paste preparation method. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0081] Example 12 Unlike Example 2, this example adds 0.5 parts by weight of a blocked isocyanate curing agent to the electrode paste preparation method. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0082] Example 13 Unlike Example 2, this example adds 2 parts by mass of a blocked isocyanate curing agent to the electrode paste preparation method. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0083] Example 14 Unlike Example 2, in this example, 2 parts silver acetate are added and 2 parts nano silver powder are reduced by mass in the preparation method of electrode paste. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0084] Example 15 Unlike Example 2, the nano-silver powder used in this example is coated with triethanolamine. By mass, 0.5 parts imidazole curing accelerator, 0.5 parts phosphate dispersant, 0.5 parts phthalate coupling agent, 0.5 parts acrylate leveling agent, and 5 parts reactive diluent are added to the electrode paste preparation method. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0085] Example 16 Unlike Example 2, the solvent used in this example is a mixture of diethylene glycol ethyl ether acetate and isooctanol in a mass ratio of 1:1. The rest is the same as in Example 2. The performance test results of the prepared low-temperature silver-coated copper paste are shown in Table 1.

[0086] Comparative Example 1 Unlike Example 2, this comparative example electrode slurry was prepared without the addition of epoxy resin, hydroxyl acrylic resin and blocked isocyanate curing agent. The rest was the same as in Example 2. The performance test results of the prepared electrode slurry are shown in Table 1.

[0087] Comparative Example 2 Unlike Example 2, the curing agent used in this example is an unsealed isocyanate curing agent (unsealing temperature 25°C). The rest is the same as in Example 2. The performance test results of the prepared electrode slurry are shown in Table 1.

[0088] Comparative Example 3 Unlike Example 2, the curing agent used in this example is a closed isocyanate curing agent with a desealing temperature of 180°C, and the curing temperature is set to 170°C. The rest is the same as in Example 2. The performance test results of the prepared electrode paste are shown in Table 1.

[0089] Table 1 Electrode Slurry Performance Table

[0090] As shown in Table 1, the electrode pastes prepared using silver-coated copper powder with different silver contents in Examples 1 to 4 all exhibited lower volume resistivity, smaller printed linewidths, and better adhesion than Comparative Example 1. Among them, Example 2, using silver-coated copper powder with a silver content of 12%, showed the lowest volume resistivity, a printed linewidth of 26 μm, high adhesion, and the best overall performance. It is evident that using the silver-coated copper powder of this application, while reducing the silver content, still maintains excellent conductivity and printability.

[0091] A comparison of Examples 2 with Examples 5-7 shows that when the mass ratio of epoxy resin to hydroxyl acrylic resin changes from 1.5:0.5 to 0.4:1.6, the volume resistivity decreases with increasing hydroxyl acrylic resin content, but the adhesion also decreases. Overall, Example 2 is relatively optimal. This indicates that appropriately increasing the proportion of hydroxyl acrylic resin is beneficial for reducing resistivity, but excessive addition may affect adhesion.

[0092] As can be seen from the comparison between Example 2 and Examples 8 and 9, the amount of nano silver powder has a significant impact on conductivity and printability. This application limits it to 5-30 parts to achieve a good balance between conductivity and cost.

[0093] As can be seen from the comparison between Example 2 and Examples 10 and 11, too low a amount of curing resin will lead to insufficient cross-linking, which will affect the fixation and adhesion of the conductive network; when the amount is moderate, the best performance can be obtained. It is reasonable to limit it to the range of 0.5 parts to 2 parts in this application.

[0094] As can be seen from the comparison between Example 2 and Examples 12 and 13, if the amount of curing agent is too low, the curing will be incomplete, affecting the stability and adhesion of the conductive network; when the amount is moderate or slightly higher, the performance is better. This application limits it to the range of 0.5 parts to 2 parts to meet different process requirements.

[0095] A comparison between Example 2 and Example 14 shows that by introducing two parts of organic silver salt into the conductive filler and correspondingly reducing the amount of nano-silver powder, the bulk resistivity of Example 14 decreased while the adhesion remained high. This demonstrates that the introduction of organic silver salt can effectively reduce resistivity by generating nano-silver particles in situ, further filling the conductive network, enhancing inter-particle connections, and improving conductivity.

[0096] A comparison of Examples 2 and 15 shows that when triethanolamine-coated silver nanopowder is used, and 0.5 parts of imidazole accelerator, 0.5 parts of phosphate dispersant, 0.5 parts of phthalate coupling agent, 0.5 parts of acrylate leveling agent, and 5 parts of reactive diluent are added, the bulk resistivity of Example 15 decreases to 5.02 μΩ·cm, the printed linewidth is refined to 22 μm, and the adhesion remains high. This demonstrates that by optimizing the type and amount of additives, conductivity, printing accuracy, and film quality can be improved simultaneously, achieving a comprehensive improvement in overall performance.

[0097] A comparison of Examples 2 and 16 shows that when a mixed solvent of diethylene glycol ethyl ether acetate and isooctanol is used, the bulk resistivity of Example 16 is 5.76 μΩ·cm, which is comparable to 5.74 μΩ·cm in Example 2, and the printed line width and adhesion remain consistent. This demonstrates that the organic carrier solvent system of this application has good adaptability, and suitable solvent types can be selected according to actual needs.

[0098] A comparison of Example 2 and Comparative Example 1 shows that Comparative Example 1, without the addition of a curing system, exhibits a high volume resistivity of 25.30 μΩ·cm, an increased printing linewidth of 35 μm, and extremely low adhesion. This demonstrates that the curing system is a key component for achieving low resistivity, high adhesion, and good printability; without it, the paste cannot form an effective conductive network and polymer skeleton.

[0099] A comparison between Example 2 and Comparative Example 2 shows that Comparative Example 2 used an unblocked isocyanate curing agent, which began to react at room temperature, resulting in poor storage stability of the paste, decreased printing performance, increased volume resistivity to 15.80 μΩ·cm, increased printed linewidth to 38 μm, and low adhesion. Therefore, using a blocked curing agent and controlling the unblocking temperature within an appropriate range is crucial for ensuring the storage stability and final performance of the paste.

[0100] A comparison of Example 2 and Comparative Example 3 shows that Comparative Example 3 used a blocked isocyanate curing agent with a desealing temperature of 180°C and set the curing temperature to 170°C, which is lower than the desealing temperature. This resulted in incomplete curing, an increase in volume resistivity to 18.50 μΩ·cm, an increase in printed linewidth to 36 μm, and low adhesion. It is evident that the desealing temperature of the curing agent must be lower than the curing temperature, and the curing temperature should be higher than the desealing temperature to ensure complete curing. This application limits the desealing temperature of the curing agent to 80°C-150°C and requires it to be lower than the critical oxidation temperature of silver-coated copper powder, which has significant technical implications.

[0101] In summary, this application, by selecting silver content and particle size of silver-coated copper powder that meet the limitations of this application, employing a curing system composed of epoxy resin and hydroxyl acrylic resin, selecting a blocked isocyanate curing agent with a suitable unsealing temperature, introducing nano-silver powder and organic silver salt as conductive fillers, adding various functional additives, and rationally matching the amounts of each component, has obtained a high-performance electrode paste with low resistivity, fine linewidth, high adhesion, and low silver content. Compared with the comparative example, the embodiments of this application show significant advantages in all performance indicators, demonstrating that the electrode paste of this application is advanced and practical.

[0102] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. An electrode paste, characterized in that, include: The invention comprises silver-coated copper powder, conductive filler, binder system, solvent, and additives. The binder system includes a curing resin and a curing agent. The curing resin can undergo a crosslinking reaction with the curing agent at a first temperature, which is lower than the critical oxidation temperature of the silver-coated copper powder.

2. The electrode paste according to claim 1, characterized in that, The electrode paste comprises, by weight, 60-88 parts of silver-coated copper powder, 5-35 parts of conductive filler, 0.5-2 parts of curing resin, 0.5-2 parts of curing agent, 4-10 parts of solvent, and 0-7.5 parts of additives.

3. The electrode paste according to claim 1, characterized in that, The cured resin includes a first resin and a second resin. The first resin has a first functional group that can undergo a crosslinking reaction with the curing agent, and the second resin has a second functional group that can undergo a crosslinking reaction with the curing agent.

4. The electrode paste according to claim 3, characterized in that, The first functional group and the second functional group are each independently selected from one or more of epoxy, hydroxyl and carboxyl groups.

5. The electrode paste according to claim 3, characterized in that, The first resin is an epoxy resin, and the second resin is a hydroxyl acrylic resin. The epoxy resin is one or more epoxy resins with an epoxy equivalent of 100-200, and the hydroxyl acrylic resin is one or more hydroxyl acrylic resins with a hydroxyl value between 50 mg KOH / g and 80 mg KOH / g; and / or, The mass ratio of the first resin to the second resin is 1:0.5-1:

8.

6. The electrode paste according to claim 1, characterized in that, The curing agent is a closed-type curing agent, and the unsealing temperature of the closed-type curing agent is lower than the critical oxidation temperature of the silver-coated copper powder; and / or, The curing agent is a blocked isocyanate curing agent, and the unblocking temperature of the curing agent is 80℃-150℃.

7. The electrode paste according to claim 1, characterized in that, The bonding system further comprises 0 to 0.5 parts by weight of a curing accelerator, wherein the curing accelerator is one or more of imidazole curing accelerators, substituted urea curing accelerators, boron trifluoride complexes, hexafluoroantimonates, and phenolic accelerators.

8. The electrode paste according to claim 1, characterized in that, The electrode slurry further includes 0-0.4 parts by weight of a polymer resin, wherein the polymer resin is one or more of ethyl cellulose, PVB resin and cellulose acetate butyrate.

9. The electrode paste according to claim 1, characterized in that, The conductive filler comprises 5 to 30 parts by weight of nano-silver powder.

10. The electrode paste according to claim 9, characterized in that, The nano silver powder includes one or more nano silver powders with a particle size of 100 nm to 500 nm; The surface of the nano-silver powder is coated with a coating agent selected from one or more of lauric acid, gallic acid, capric acid, polyglycerol, polyvinyl alcohol, oleylamine, and triethanolamine.

11. The electrode paste according to claim 1, characterized in that, The conductive filler further comprises 0 to 5 parts by weight of an organic silver salt, wherein the organic silver salt is one or more of silver acetate, silver oxalate, silver maronate, silver malonate, and silver lactate.

12. The electrode paste according to claim 1, characterized in that, The additives include one or more of the following: thixotropic agents, reactive diluents, coupling agents, dispersants, and leveling agents.

13. The electrode paste according to claim 1, characterized in that, The additives, by weight, include 0-0.5 parts of thixotropic agent, 0-5 parts of reactive diluent, 0-0.5 parts of coupling agent, 0-0.5 parts of dispersant, and 0-0.5 parts of leveling agent.

14. The electrode paste according to claim 12 or 13, characterized in that, The thixotropic agent is one or more of polyamide wax, polyurea, hydrogenated castor oil, and oleogel; The reactive diluent is one or more of mono- or polyfunctional glycidyl ethers and glycidyl esters or acrylic reactive diluents; The coupling agent is one or more of aminosilane coupling agents, phthalate coupling agents, and aluminate coupling agents; The dispersant is one or more of phosphate esters, acrylates, ethylene oxide type and fatty acids; The leveling agent is one or more of acrylates and silicones.

15. The electrode paste according to any one of claims 1-13, characterized in that, The silver-coated copper powder is a single-crystal silver-coated copper powder, the silver content of the single-crystal silver-coated copper powder is 3%-15%, and the particle size D50 of the single-crystal silver-coated copper powder is 1μm-6μm, D100 < 10μm; and / or, The solvent includes one or more of dipropylene glycol methyl ether, benzyl alcohol, propylene glycol phenyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl ether acetate, 3-methoxy-3-methylbutanol, dodecyl alcohol ester, diethylene glycol butyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, and isooctyl alcohol.

16. A solar cell, characterized in that, The electrodes of the solar cell comprise the electrode paste as described in any one of claims 1-15.

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