Preparation method of glass powder for N-type silver-aluminum paste

Abstract

The application provides a preparation method of N-type silver-aluminum paste glass powder and relates to the technical field of conductive materials of metals or alloys. The preparation method of the N-type silver-aluminum paste glass powder comprises the following steps: weighing TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3, uniformly mixing the TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 to obtain a mixture X; sintering the mixture X to obtain a mixture Y; cooling and treating the mixture Y to obtain a mixture Z; ball-milling the mixture Z to obtain a mixture Q; screening the mixture Q in a vibrating screen, uniformly mixing the screened mixture Q and the graphene, and then heating and treating to obtain the N-type silver-aluminum paste glass powder. The glass powder prepared by the method has the advantages of high flowability, a low softening point and excellent photoelectric performance.

Description

Technical Field

[0001] The present application relates to the technical field of conductive materials containing metals or alloys, and in particular to a method for preparing glass powder for N-type silver-aluminum paste. Background Art

[0002] For silver-aluminum pastes used in N-type solar cells, glass powder is a crucial factor in determining contact resistance, surface etching reactions, and the overall electrical performance of the cell, requiring it to possess excellent electrical and mechanical properties. Furthermore, the type and amount of glass powder significantly influence the open-circuit voltage and fill factor of the paste under high-temperature sintering conditions. During the sintering step of the solar cell manufacturing process, the glass powder in the silver-aluminum paste corrodes the SiNx anti-reflective film and bonds to the underlying silicon layer. A sufficient and complete etching reaction ensures a good ohmic contact.

[0003] Although glass powder accounts for a relatively small proportion of the paste (1-5wt%), it plays a vital role in the formation of the Ag-Si metal semiconductor contact, ensuring its stable bonding performance by corroding the SiNx anti-reflection film and reacting with it. As a bonding phase, glass powder not only promotes the adhesion of the silver-aluminum paste to the silicon substrate of the solar cell during the sintering process, but also affects the sintering kinetics of the conductive functional phase metal powder. In addition to possessing the relevant properties of the basic bonding phase, the glass powder used in the silver-aluminum paste for the front electrode must also be able to completely etch with the silicon nitride anti-reflection film during the sintering process. After sintering, a contact layer is formed between the Ag and Si, enabling the silver powder and the silicon substrate to form a good ohmic contact, thereby effectively achieving the goal of improving the photoelectric conversion efficiency of the solar cell.

[0004] Currently, the glass powders used are essentially lead-based systems. Glass powder undergoes an oxidation-reduction reaction with silicon nitride film at high temperatures, and the reduced lead-containing glass produces lead as a byproduct, posing a threat to environmental protection and harming human health. However, because lead-containing glass has excellent softening fluidity during the interfacial reaction, liquid silver flows through the glass and reaches the P+ emitter, where nanosilver crystals precipitate as the glass cools. The greater the range of glass flow, the stronger the silver-silicon contact. Lead-free glass powders struggle to achieve the same high softening fluidity as lead-containing glass powders. Therefore, a lead-free glass powder is needed that combines the high fluidity and low softening point of lead-containing glass with excellent optoelectronic properties. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing glass powder for N-type silver-aluminum paste. The glass powder prepared by this method has the advantages of high fluidity, low softening point and excellent photoelectric properties.

[0006] In order to solve the above problems, the technical method adopted by the present invention is:

[0007] The present invention provides a method for preparing glass powder for N-type silver-aluminum paste, comprising the following steps:

[0008] Weigh TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3, and mix TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 to obtain a mixture X;

[0009] Mixture X is sintered to obtain mixture Y;

[0010] After the mixture Y is cooled, a mixture Z is obtained;

[0011] The mixture Z is ball-milled to obtain a mixture Q;

[0012] The mixture Q is placed in a vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, followed by heating treatment to obtain the glass powder for the N-type silver-aluminum paste.

[0013] In some embodiments of the present application, the weight ratio of the above-mentioned TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3 is (10-40): (10-30): (1-5): (1-3): (0.5-1): (0.1-1.5): (0.1-0.5): (0.1-0.3).

[0014] In some embodiments of the present application, the sintering is specifically to place the mixture X in a sintering furnace and sinter at a temperature of 800-900° C. for 40-90 minutes.

[0015] In some embodiments of the present application, the cooling step specifically involves placing the mixture Y on a cooling roller and cooling it at a rotation speed of 4-8 rpm for 1-2.5 hours.

[0016] In some embodiments of the present application, the ball milling treatment specifically comprises ball milling the mixture Z at a rotation speed of 300-380 rpm for 3-8 hours.

[0017] In some embodiments of the present application, the size of the vibrating screen is 300 mesh.

[0018] In some embodiments of the present application, after the mixture Q and graphene are mixed, they are heated at 90-200° C. for 3-8 hours.

[0019] Compared with the prior art, the invention of this application has at least the following advantages or beneficial effects:

[0020] This application replaces lead with TeO2 and Bi2O3, achieving environmental benefits. Li2O and other materials serve as the outer glass network, while ZnO and other materials serve as the intermediate glass network. ZnO lowers the glass transition temperature, thermal expansion coefficient, and melting point. Al2O3 improves the acid resistance of the glass powder. The addition of Cr2O3 further stabilizes the glass powder. The mixture is sintered, cooled, and ball-milled before being mixed with graphene and heated. This improves the photoelectric properties of the glass powder. Graphene allows unstable electrons to be conducted to the conductive substrate, increasing the photoelectron transition rate. Dispersing the graphene in the mixture Q and then sintering effectively lowers the glass softening temperature. The resulting glass powder exhibits high fluidity, a low softening point, and excellent photoelectric properties. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to specific embodiments.

[0023] The present invention provides a method for preparing glass powder for N-type silver-aluminum paste, comprising the following steps:

[0024] Weigh TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3, and mix TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 to obtain a mixture X;

[0025] Mixture X is sintered to obtain mixture Y;

[0026] After the mixture Y is cooled, a mixture Z is obtained;

[0027] The mixture Z is ball-milled to obtain a mixture Q;

[0028] The mixture Q is placed in a vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, followed by heat treatment to obtain glass powder for N-type silver-aluminum paste.

[0029] This application replaces lead with TeO2 and Bi2O3, achieving environmental benefits. Li2O and other materials serve as the outer glass network, while ZnO and other materials serve as the intermediate glass network. ZnO lowers the glass transition temperature, thermal expansion coefficient, and melting point. Al2O3 improves the acid resistance of the glass powder. The addition of Cr2O3 further stabilizes the glass powder. The mixture is sintered, cooled, and ball-milled before being mixed with graphene and heated. This improves the photoelectric properties of the glass powder. Graphene allows unstable electrons to be conducted to the conductive substrate, increasing the photoelectron transition rate. Dispersing the graphene in the mixture Q and then sintering effectively lowers the glass softening temperature. The resulting glass powder exhibits high fluidity, a low softening point, and excellent photoelectric properties.

[0030] In some embodiments of the present application, the weight ratio of the above-mentioned TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3 is (10-40): (10-30): (1-5): (1-3): (0.5-1): (0.1-1.5): (0.1-0.5): (0.1-0.3).

[0031] In some embodiments of the present application, the weight ratio of TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 is 40:15:3:2:0.8:1:0.3:0.2. The glass powder obtained under this ratio has the best comprehensive performance.

[0032] In some embodiments of the present application, the sintering is specifically to place the mixture X in a sintering furnace matched with the wire mesh, and sinter at a temperature of 800-900° C. for 40-90 minutes.

[0033] In some embodiments of the present application, the cooling step specifically involves placing the mixture Y on a cooling roller and cooling it at a rotation speed of 4-8 rpm for 1-2.5 hours.

[0034] In some embodiments of the present application, the ball milling treatment specifically involves placing the mixture Z in a ball mill at a speed of 300-380 rpm for 3-8 hours. After sufficient ball milling, the mixture Z can be made into a sufficiently fine particle size, which can not only improve the mixing uniformity of the graphene and the graphene, but also facilitate subsequent use in the silver-aluminum paste.

[0035] In some embodiments of the present application, the size of the vibrating screen is 300 mesh.

[0036] In some embodiments of the present application, after the mixture Q and graphene are mixed, they are heated at 90-200° C. for 3-8 hours.

[0037] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0038] Example 1

[0039] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0040] TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 10:30:1:1:0.5:0.1:0.1:0.1, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0041] The mixture X is placed in a sintering furnace and sintered at 800°C for 40 minutes to obtain a mixture Y;

[0042] Place the mixture Y on a cooling roller and cool it at 4 rpm for 1 h to obtain a mixture Z;

[0043] The mixture Z was ball-milled at 300 rpm for 3 h to obtain a mixture Q;

[0044] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at 90° C. for 3 hours to obtain glass powder for N-type silver-aluminum paste.

[0045] Example 2

[0046] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0047] TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 15:25:3:2:0.6:0.9:0.2:0.1, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0048] The mixture X is placed in a sintering furnace and sintered at 830°C for 50 min to obtain a mixture Y;

[0049] The mixture Y was placed on a cooling roller and cooled at a speed of 6 rpm for 1.5 h to obtain a mixture Z;

[0050] The mixture Z was ball-milled at 320 rpm for 4 h to obtain a mixture Q;

[0051] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at 120° C. for 5 hours to obtain glass powder for N-type silver-aluminum paste.

[0052] Example 3

[0053] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0054] TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 40:15:3:2:0.8:1:0.3:0.2, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0055] The mixture X is placed in a sintering furnace and sintered at 850°C for 70 minutes to obtain a mixture Y;

[0056] The mixture Y was placed on a cooling roller and cooled at a speed of 6 rpm for 2 h to obtain a mixture Z;

[0057] The mixture Z was ball-milled at 350 rpm for 3-8 h to obtain a mixture Q;

[0058] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at a temperature of 190° C. for 5 hours to obtain glass powder for N-type silver-aluminum paste.

[0059] Example 4

[0060] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0061] TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 20:15:2:1:0.9:1.2:0.4:0.3, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0062] The mixture X is placed in a sintering furnace and sintered at 880°C for 80 min to obtain a mixture Y;

[0063] The mixture Y was placed on a cooling roller and cooled at a speed of 7 rpm for 2 h to obtain a mixture Z;

[0064] The mixture Z was ball-milled at 360 rpm for 6 h to obtain a mixture Q;

[0065] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at a temperature of 160° C. for 6 hours to obtain glass powder for N-type silver-aluminum paste.

[0066] Example 5

[0067] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0068] TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 40:10:5:3:1:1.5:0.5:0.3, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0069] The mixture X is placed in a sintering furnace and sintered at 900°C for 90 minutes to obtain a mixture Y;

[0070] The mixture Y was placed on a cooling roller and cooled at 8 rpm for 2.5 h to obtain a mixture Z;

[0071] The mixture Z was ball-milled at 380 rpm for 8 h to obtain a mixture Q;

[0072] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at a temperature of 200° C. for 8 hours to obtain glass powder for N-type silver-aluminum paste.

[0073] Comparative Example 1

[0074] This comparative example is basically the same as Example 3, except that no graphene is added.

[0075] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0076] TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 were weighed in a weight ratio of 40:15:3:2:1:0.3:0.2, and TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 were uniformly mixed to obtain a mixture X;

[0077] The mixture X is placed in a sintering furnace and sintered at 850°C for 70 minutes to obtain a mixture Y;

[0078] The mixture Y was placed on a cooling roller and cooled at a speed of 6 rpm for 2 h to obtain a mixture Z;

[0079] The mixture Z was ball-milled at 350 rpm for 3-8 h to obtain a mixture Q;

[0080] The mixture Q was placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q was treated at a temperature of 190° C. for 5 hours to obtain glass powder for N-type silver-aluminum paste.

[0081] Comparative Example 2

[0082] This comparative example is basically the same as Example 3, except that TeO2 and Bi2O3 are replaced by PbO.

[0083] A method for preparing glass powder for N-type silver-aluminum paste comprises the following steps:

[0084] PbO, Sb2O3, Cr2O3, graphene, Li2O, ZnO, and Al2O3 are weighed in a weight ratio of 55:3:2:0.8:1:0.3:0.2, and PbO, Sb2O3, Cr2O3, Li2O, ZnO, and Al2O3 are uniformly mixed to obtain a mixture X;

[0085] The mixture X is placed in a sintering furnace and sintered at 850°C for 70 minutes to obtain a mixture Y;

[0086] The mixture Y was placed on a cooling roller and cooled at a speed of 6 rpm for 2 h to obtain a mixture Z;

[0087] The mixture Z was ball-milled at 350 rpm for 3-8 h to obtain a mixture Q;

[0088] The mixture Q is placed in a 300-mesh vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, and then treated at a temperature of 190° C. for 5 hours to obtain glass powder for N-type silver-aluminum paste.

[0089] Experimental example

[0090] (1) The transition temperatures (Tg) of the glass powders prepared in Examples 1-5 and Comparative Examples 1-2 were measured using a differential scanning calorimeter. The results are shown in Table 1.

[0091] Table 1

[0092] Sample Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Tg(℃) 299 306 292 293 294 304 315

[0093] Table 1 shows that the glass powder prepared in this application has a relatively low transition temperature. Comparing Examples 1-5, it can be seen that the glass powder of Example 3 of this application has a relatively low transition temperature. This allows the glass powder to flow earlier during sintering, reducing the viscosity of the molten glass and improving its fluidity, making it easier to wet the silver particles, forming a dense conductive layer and improving its conductivity. Comparing Example 3 with Comparative Example 1 shows that the addition of graphene can reduce the transition temperature of the glass powder and improve its wettability. Comparing Example 3 with Comparative Example 2 shows that replacing PbO with TeO2 and Bi2O3 can effectively reduce the transition temperature of the glass powder.

[0094] (2) The glass powder prepared in Examples 1-5 and Comparative Examples 1-2 was mixed with silver powder and an organic carrier (DL2126ZQ produced by Jiurui Plastic Raw Materials Co., Ltd.) in a weight ratio of 3:87:10, stirred evenly, and fully ground until there were no obvious particles and the fineness was less than 5 μm to obtain a silver paste.

[0095] The silver pastes of Examples 1-5 and Comparative Examples 1-2 were screen-printed onto 156 mm × 156 mm N-type polycrystalline silicon wafers. After allowing to level for 5 minutes, the wafers were dried in an oven at 150°C for 5 minutes. The wafers were then placed in a box-type sintering furnace, heated to 520°C, and sintered for 15 minutes. The sintering process was then controlled to take 60 minutes to produce test samples. The electrical properties of the cells were tested, including short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), and photoelectric conversion efficiency (EFF). The test results are shown in Table 2.

[0096] Table 2

[0097] Sample Isc(A) Voc(V) FF(%) EFF (%) Example 1 9.5801 0.6672 21.23 78.91 Example 2 9.5872 0.6679 21.69 79.39 Example 3 9.5993 0.6692 21.72 80.24 Example 4 9.5936 0.6693 21.65 80.21 Example 5 9.5939 0.6681 21.69 80.10 Comparative Example 1 9.3591 0.6659 21.35 79.25 Comparative Example 2 9.4728 0.6667 21.51 79.52

[0098] From Table 2, it can be seen that the glass powder prepared in Example 3 of the present application has the best comprehensive performance.

[0099] In summary, this application achieves environmental protection by replacing Pb with TeO2 and Bi2O3. Li2O and other materials are used as glass network outer bodies, and ZnO and other materials are used as glass network intermediates. ZnO reduces the glass transition temperature, thermal expansion coefficient, and melting point. Al2O3 improves the acid resistance of the glass powder. The introduction of Cr2O3 increases the stability of the glass powder. After the mixture is sintered, cooled, and ball-milled, it is mixed with graphene and heated to improve the photoelectric properties of the glass powder. Through the action of graphene, unstable electrons are conducted to the conductive substrate, increasing the transition rate of photoelectrons. At the same time, dispersing graphene in the mixture Q and then sintering can effectively reduce the glass softening temperature. The glass powder finally obtained by this method has the advantages of high fluidity, low softening point, and high photoelectric properties.

[0100] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A method for preparing glass powder for N-type silver-aluminum paste, characterized in that: The steps include: Weigh TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3, and mix TeO2, Bi2O3, Sb2O3, Cr2O3, Li2O, ZnO and Al2O3 to obtain a mixture X; Mixture X is sintered to obtain mixture Y; After the mixture Y is cooled, a mixture Z is obtained; The mixture Z is ball-milled to obtain a mixture Q; The mixture Q is placed in a vibrating screen for precise high-frequency screening, and then the screened mixture Q and graphene are evenly mixed, followed by heating to obtain the glass powder for the N-type silver-aluminum paste; The weight ratio of TeO2, Bi2O3, Sb2O3, Cr2O3, graphene, Li2O, ZnO and Al2O3 is (10-40): (10-30): (1-5): (1-3): (0.5-1): (0.1-1.5): (0.1-0.5): (0.1-0.3).

2. The method for preparing glass powder for N-type silver-aluminum paste according to claim 1, characterized in that: The sintering is specifically to place the mixture X in a sintering furnace and sinter at a temperature of 800-900° C. for 40-90 minutes.

3. The method for preparing glass powder for N-type silver-aluminum paste according to claim 1, characterized in that: The cooling treatment specifically includes placing the mixture Y in a cooling roller and cooling it at a rotation speed of 4-8 rpm for 1-2.5 hours.

4. The method for preparing glass powder for N-type silver-aluminum paste according to claim 1, characterized in that: The ball milling treatment specifically comprises ball milling the mixture Z at a rotation speed of 300-380 rpm for 3-8 hours.

5. The method for preparing glass powder for N-type silver-aluminum paste according to claim 1, characterized in that: The vibrating screen has a size of 300 meshes.

6. The method for preparing glass powder for N-type silver-aluminum paste according to claim 1, characterized in that: After the mixture Q and graphene are mixed, they are heated at a temperature of 90-200° C. for 3-8 hours.