Electrode slurry, method for preparing metal electrode and solar cell

Abstract

The present invention relates to the technical field of solar cells, and provides an electrode slurry, a method for preparing a metal electrode, and a solar cell. The electrode slurry comprises a metal oxide, a solid reducing agent, and an organic system; the metal oxide comprises one or both of copper oxide and cuprous oxide. The electrode slurry uses conductive and reducing graphite powder and / or graphene as a reducing agent, the reaction product is gas, there are no by-products, it is safe and environmentally friendly, and copper grid lines can be completely used to replace expensive silver paste, thereby achieving a significant cost reduction; the prepared metal electrode has the advantages of low porosity, good density, low resistivity, etc.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to an electrode slurry, a method for preparing a metal electrode and a solar cell. Background Art

[0002] Heterojunction cells have the advantages of high conversion efficiency, simple structure, short process flow, no PID phenomenon and thin film, and are very competitive in future photovoltaic cell technology. According to the forecast of the Photovoltaic Association, the market share of heterojunction cells will grow steadily from 2022, and is expected to reach about 40% by 2030.

[0003] The biggest obstacle to the industrialization of heterojunction batteries is cost, and cost reduction is the top priority of heterojunction batteries. The grid electrode of conventional heterojunction battery cells is prepared by screen printing low-temperature silver paste. Low-temperature silver paste is expensive, and the consumption of low-temperature silver paste is large in the preparation of grid electrode, which leads to the silver paste cost accounting for 42% of the non-silicon cost of heterojunction batteries. Therefore, cost reduction is an important improvement direction for heterojunction batteries.

[0004] "Silver removal" and "silver reduction" are the only way to "reduce costs and increase efficiency" for heterojunctions. The prior art discloses a method for preparing copper electrodes by laser reduction of copper oxide ink, which uses organic ethylene glycol and copper oxide to make ink, and then uses laser to decompose ethylene glycol to form acetaldehyde. With the assistance of laser energy, acetaldehyde reduces copper oxide to form a copper metal electrode. In this method, the volatilization of organic matter makes the copper electrode have a higher porosity, resulting in poor density of the copper electrode, and the resistivity is one to two orders of magnitude higher than that of pure copper.

[0005] Therefore, developing a preparation method for metal electrodes with low porosity, good density and low resistivity is of great economic value. Summary of the invention

[0006] The purpose of the present invention is to overcome the above problems existing in the prior art, and to provide an electrode slurry, a method for preparing a metal electrode and a solar cell, wherein the solar cell comprises a metal electrode prepared by the method. The method for preparing a metal electrode provided by the present invention has the advantages of simple process flow, high process efficiency, low production cost and environmental protection; the prepared metal electrode has the advantages of low porosity, good density and low resistivity.

[0007] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a metal electrode, the method comprising the following steps:

[0008] S1: In an organic system, metal oxides and solid reducing agents are mixed;

[0009] S2: placing the mixture obtained in step S1 on the surface of the substrate;

[0010] S3: irradiating the mixture on the surface of the substrate with a laser, and forming a preset graphic area on which a metal single substance is attached on the substrate through the movement of the laser.

[0011] In one example, the metal oxide includes one or both of copper oxide and cuprous oxide.

[0012] In one example, the metal oxide is cupric oxide and / or cuprous oxide.

[0013] In one example, the solid reducing agent is graphite and / or graphene.

[0014] In one example, the mass ratio of the metal oxide to the solid reducing agent is 1:(0.8-5).

[0015] In a preferred embodiment, the mass ratio of the metal oxide to the solid reducing agent is 1:(1-3).

[0016] In one example, the D50 of the metal oxide is 50 nm-1000 nm.

[0017] In one example, the D50 of the solid reducing agent is 50 nm-1000 nm.

[0018] In one example, the organic system includes a base resin and a diluent.

[0019] In one example, the base resin is selected from at least one of polyurethane resin, epoxy resin, acrylic resin and polyether resin.

[0020] In one example, the diluent is selected from at least one of dipropylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, ethyl acetate and butyl acetate.

[0021] In one example, in step S3, the parameters of the laser include: pulse frequency 1500-2500 kHz, pulse energy 400-600 nJ, laser wavelength 400-1200 nm, pulse width <15 ps, and scanning speed 2-10 mm / s.

[0022] In one example, the substrate is selected from at least one of single crystal silicon, polycrystalline silicon, polymer materials, ceramics and glass.

[0023] In one example, the substrate is a silicon substrate including single crystal silicon and / or polycrystalline silicon.

[0024] In one example, the metal electrode is a metal electrode in a solar cell, a secondary battery, a circuit board, a light emitting diode or a microelectronic device.

[0025] In one example, the metal electrode is a grid line electrode of a solar cell.

[0026] A second aspect of the present invention provides a solar cell, comprising a metal electrode, wherein the metal electrode is prepared by the method according to the first aspect of the present invention.

[0027] The present invention adopts the above technical solution to achieve the following beneficial effects:

[0028] (1) The electrode slurry provided by the present invention uses conductive and reducing graphite powder and / or graphene as a reducing agent. The reaction product is gas, without by-products, safe and environmentally friendly. Copper grid wire can completely replace expensive silver paste, thereby achieving significant cost reduction.

[0029] (2) The method for preparing metal electrodes provided by the present invention introduces a laser process to realize direct writing of copper grid lines of heterojunction batteries under low temperature conditions; the process is highly efficient, the laser scanning rate is adjustable, and the grid line forming process can be quickly realized; the process flow is simple, and conventional heterojunction metallization equipment can be reduced, thereby reducing equipment costs.

[0030] (3) The solar cell prepared by the present invention has a metal electrode with the advantages of low porosity, good density and low resistivity.

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these range values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Shown is a schematic flow chart of the method for preparing a metal electrode according to the present invention.

[0033] Figure numerals: 1 - substrate; 2 - electrode slurry; 3 - laser; 4 - metal electrode. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0036] The first aspect of the present invention provides an electrode slurry, comprising a metal oxide, a solid reducing agent and an organic system; the metal oxide comprises one or both of cupric oxide and cuprous oxide.

[0037] In one example, the metal oxide may be copper oxide, the metal oxide may also be cuprous oxide, or the metal oxide may be a mixture of copper oxide and cuprous oxide.

[0038] In the present invention, the solid reducing agent can be selected according to actual needs, as long as it can reduce the metal oxide to a metal element during laser irradiation treatment.

[0039] In the present invention, the organic system has a similar effect as a binder, and binds the mixture of metal oxide and solid reducing agent together to form ink or precursor slurry, which facilitates the coating of the precursor slurry on the substrate. The selection principle of the organic system is: it does not decompose under laser irradiation, or does not produce gas when decomposed, or decomposes to produce a small amount of gas, and does not chemically react with the metal oxide and solid reducing agent.

[0040] In the present invention, after the solid reducing agent and the metal oxide are mixed in the organic system, no redox reaction will occur, and both components will maintain a relatively stable chemical state. Only when the laser provides energy, the solid reducing agent will undergo a redox reaction to reduce the metal oxide to a single metal.

[0041] In the present invention, when the electrode slurry is used to prepare the grid line electrode of the solar cell, the inexpensive copper grid line can be used to replace the expensive silver grid line prepared by silver paste, so as to achieve "silver removal" or "silver reduction", which can greatly reduce the production cost of the solar cell.

[0042] In order to further improve the performance of the electrode slurry and prepare a metal electrode with better physical properties, one or more of its characteristics may be optimized.

[0043] In one example, the solid reducing agent is graphite and / or graphene, that is, the solid reducing agent may be graphite, the solid reducing agent may also be graphene, or the solid reducing agent may be a mixture of graphite and graphene.

[0044] In order to improve the efficiency of reducing metal oxides by solid reducing agents and make the process of preparing metal electrodes more efficient, the mass ratio of metal oxides to solid reducing agents is preferably 1:(0.8-5).

[0045] In one example, the mass ratio of the metal oxide to the solid reducing agent can be 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5.

[0046] In a preferred embodiment, the mass ratio of the metal oxide to the solid reducing agent may be 1:(1-3).

[0047] In the present invention, the metal oxide and the solid reducing agent can be in powder form, so that the metal oxide and the solid reducing agent can be better dispersed in the organic system, and then the metal oxide and the solid reducing agent can be more evenly attached to the surface of the substrate, making the thickness of the prepared metal electrode more uniform.

[0048] In one example, the D50 of the metal oxide is 50 nm-1000 nm, preferably 60 nm-500 nm.

[0049] In one example, the D50 of the solid reducing agent is 50 nm-1000 nm, preferably 60 nm-500 nm.

[0050] In the present invention, the value of D50 can be obtained by testing with a laser particle size analyzer.

[0051] In one example, the organic system includes a base resin and a diluent. That is, the organic system of the present invention can be a mixture of a base resin and a diluent, and the base resin and diluent used to prepare ink or paste can be selected in the art according to the selection principle of the above-mentioned organic system.

[0052] Exemplarily, the matrix resin is selected from at least one of polyurethane resin, epoxy resin, acrylic resin and polyether resin.

[0053] In one example, the base resin is a polyurethane resin, or the base resin is an epoxy resin, or the base resin is a combination of a polyurethane resin and an epoxy resin.

[0054] Exemplarily, the diluent is selected from at least one of dipropylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, ethyl acetate and butyl acetate.

[0055] In the present invention, the organic system can be prepared by simply mixing a base resin and a diluent.

[0056] In order to achieve a better dissolution effect of the solid reducing agent and the metal oxide in the organic system, the method for preparing the organic system preferably comprises the following steps: bringing the base resin and the diluent into first contact at 50-90°C.

[0057] In the present invention, the first contact may be a mixed contact of the base resin and the diluent. The time of the first contact is not limited, and the first contact process can be terminated when the base resin is completely dissolved in the diluent to obtain an organic system.

[0058] In one example, the method for preparing the organic system comprises the following steps: mixing the base resin and the diluent at 70-80°C.

[0059] In one example, the mass ratio of the base resin to the diluent is 1:(1-6).

[0060] In one example, the method for preparing the organic system comprises the following steps:

[0061] 15wt%-50wt% of polyurethane resin is dissolved in 50wt%-80wt% of dipropylene glycol methyl ether acetate, and heated at a constant temperature of 70-80°C to obtain a completely dissolved organic system.

[0062] A second aspect of the present invention provides a method for preparing a metal electrode, wherein the method adopts the electrode slurry and laser process described in the first aspect of the present invention to prepare the metal electrode.

[0063] In one example, the method for preparing a metal electrode comprises the following steps:

[0064] S1: applying the above electrode slurry to the surface of the substrate;

[0065] S2: irradiating the mixture on the surface of the substrate with a laser, and forming a preset graphic area on which a metal single substance is attached on the substrate through the movement of the laser.

[0066] In the present invention, the "preset graphic area" refers to the area on the substrate corresponding to the laser moving irradiation. The specific form of the graphic area can be preset in advance according to the target graphic or target pattern of the metal electrode, for example, the gate electrode, the preset graphic can be a criss-cross gate pattern.

[0067] In the step S1, the electrode slurry may be disposed on only one surface of the substrate, or on two opposite surfaces of the substrate, or the electrode slurry may be disposed on all surfaces of the substrate.

[0068] In one example, the electrode slurry can be coated on the surface of the substrate by coating or spraying, and the coating thickness can be limited according to the performance of the metal electrode. For example, when preparing solar metal electrodes, the coating thickness can be 5 μm-10 μm.

[0069] In the present invention, metal oxide and solid reducing agent are mixed in an organic system to obtain electrode slurry, and then the electrode slurry is coated on the surface of a substrate, and the electrode slurry on the surface of the substrate is irradiated by laser movement. When the laser provides energy, the solid reducing agent in a preset pattern reduces the metal oxide to a metal element attached to the surface of the substrate, thereby preparing a patterned metal electrode. The method for preparing a metal electrode has a simple process, can reduce conventional metallization equipment, and thus reduce equipment costs; and has high process efficiency, and the laser movement scanning rate is adjustable, and the metal electrode forming process can be quickly realized.

[0070] In the present invention, the laser process parameters directly affect the performance of the prepared metal electrode, such as the width, thickness and generation speed of the metal electrode. Metal electrodes with different requirements need to select different laser emitters and adjust different laser process parameters.

[0071] In one example, the laser process parameters for preparing solar cell grid electrodes include: pulse frequency 1500-2500 kHz, pulse energy 400-600 nJ, laser wavelength 400-1200 nm, pulse width <15 ps, and scanning speed 2-10 mm / s.

[0072] In one example, there is no specific limitation on the type of laser irradiation, and it can be selected according to the requirements of the metal electrode to be prepared. For example, the laser can be a point laser, a linear laser, or a surface laser. Selecting a point laser can prepare a metal electrode with simple patterning or a point patterning; selecting a linear laser can prepare a metal electrode with complex patterning or a linear patterning; selecting a surface laser can prepare a metal electrode with more complex patterning or a higher thickness requirement.

[0073] In the present invention, the substrate selection is directly related to the technical field that the prepared metal electrode is applicable to. Exemplarily, the substrate is selected from at least one of single crystal silicon, polycrystalline silicon, polymer materials, ceramics and glass.

[0074] In one example, when the prepared metal electrode is a gate electrode of a solar cell (heterojunction cell), the substrate may be a silicon substrate containing single crystal silicon and / or polycrystalline silicon.

[0075] In one example, when the prepared metal electrode is a flexible circuit, the substrate may be a polymer base film containing a polymer material.

[0076] In one example, when the prepared metal electrode is a circuit board, the substrate may be a rigid substrate including ceramic and / or glass.

[0077] The method for preparing metal electrodes provided by the present invention can be applied to a variety of fields, such as: solar cells, secondary batteries, circuit boards, light-emitting diodes or microelectronic devices, and can also be batteries or instruments and equipment in other technical fields. As long as they contain metal electrodes prepared by the method of the present invention, they are within the protection scope of the present invention.

[0078] Exemplarily, the metal electrode is a metal electrode in a solar cell, a secondary battery, a circuit board, a light emitting diode or a microelectronic device.

[0079] In one example, the metal electrode is a metal grid electrode of a solar cell, for example, the metal electrode is a copper grid electrode of a heterojunction cell.

[0080] In the present invention, the method for preparing a metal electrode includes step S3: removing the mixture that does not participate in the reaction. In addition, the method for preparing a metal electrode may also include other operation steps, such as a drying step after coating the electrode slurry in step S1.

[0081] Reference Figure 1 The process diagram of the present invention is shown in FIG. 1 . The method for preparing a metal electrode of the present invention can be summarized into the following steps:

[0082] (i) mixing a metal oxide and a solid reducing agent in an organic system to obtain an electrode slurry 2;

[0083] (ii) coating the electrode slurry 2 on the surface of the substrate 1;

[0084] (iii) scanning and moving the laser 3 to irradiate the electrode paste 2 on the surface of the substrate 1;

[0085] (iv) removing the excess electrode slurry 2 that has not participated in the reaction to obtain a metal electrode 4.

[0086] The present invention also provides a method for preparing a solar cell copper grid electrode, comprising the following steps:

[0087] (1) adding graphite powder and copper oxide (or cuprous oxide) powder to an organic system of epoxy resin to mix and prepare an electrode slurry, wherein the mass ratio of graphite powder to copper oxide (or cuprous oxide) powder is between (1-3):1;

[0088] (2) applying the electrode slurry onto the silicon substrate of the solar cell by coating;

[0089] (3) Scanning the slurry on the surface of the substrate with a nanosecond (femtosecond) laser, with the following laser setting parameters: pulse frequency 1500-2500kHz, pulse energy 400-600nJ, laser wavelength 400-1200nm, pulse width <15ps, scanning speed 2-10mm / s;

[0090] (4) After the reaction is completed, the remaining electrode slurry is removed to obtain a copper grid line electrode.

[0091] The inventors of the present invention have found that during the reaction of ethylene glycol ink, organic matter volatilizes and water vapor is generated, resulting in a porosity of 10%-30% for the copper grid line. The specific reasons are as follows: The reduction reaction of ethylene glycol ink and copper oxide is as follows:

[0092] C2H6O2=>CH3CHO+H2O (1)

[0093] CH3CHO+CuO=>CH3COOH+Cu (2)

[0094] Reaction formula after merging: C2H6O2+CuO=>CH3COOH+Cu+H2O(3)

[0095] EG is an indirect reduction agent. Under the action of laser, ethylene glycol decomposes into acetaldehyde with reducing properties, and then acetaldehyde reduces copper oxide. In reaction formula (3), acetic acid (CH3COOH) and water (H2O) will volatilize under the local high temperature of laser, thereby causing holes in the metal gate electrode, resulting in a higher porosity of the gate. In addition, the volatilization of acetic acid has a pungent odor, which affects the local environment.

[0096] In the present invention, in the above method for preparing a metal electrode, the principle of the redox reaction is as follows:

[0097] 2CuO+C=>2Cu+CO2

[0098] 2Cu2O+C=>4Cu+CO2

[0099] Combined chemical formula: 2CuO+C=>2Cu+CO2(4)

[0100] In reaction formula (4), CO2 is a gas, colorless and odorless, and has no impact on the environment. Comparing reaction formulas (3) and (4) with the same amount of CuO for reduction reaction, the volatile gas generated by the ethylene glycol system is 4 times that of the graphite powder system. Therefore, theoretically, the porosity of the gate electrode after the ethylene glycol system is reduced is 4 times that of the graphite powder system. Having a lower porosity is one of the keys to improving the resistivity of the copper gate line. The gate line obtained by reducing copper oxide with graphite powder in the present invention has a greater resistivity advantage.

[0101] After the electrode slurry prepared by graphite powder and copper oxide (or cuprous oxide) powder reacts, the porosity of the copper grid electrode can be reduced to less than 5%, which has an improvement effect on the resistivity of the copper grid. The resistivity of the copper grid can reach the same order of magnitude as pure copper or one order of magnitude higher.

[0102] In the above method for preparing copper grid wire electrodes, graphite powder with both conductivity and reducing properties is used as a reducing agent, and the byproduct after the reaction is CO2 gas, which is environmentally friendly and safe. In addition, the graphite powder itself has conductivity. After being incorporated into the copper oxide powder, if the reaction is sufficient, a high-purity copper grid wire can be obtained. If there is graphite powder remaining after the reaction, it has little effect on the resistivity of the copper grid wire because it has conductivity itself, and a resistivity close to that of pure copper can be obtained.

[0103] The present invention proposes to use laser-induced processing of ink or slurry of copper oxide (or cuprous oxide) and graphite, and use laser energy to achieve graphite reduction of copper oxide under low temperature conditions to form copper element. The main advantages of this technology are low-temperature processing, simple process flow, high process efficiency, complete replacement of expensive silver with cheap metallic copper, and the ability to significantly reduce the production cost of metal electrodes for solar cells. In addition, when graphite is reduced to copper oxide, on the one hand, there is no problem of volatilization of reactive organic matter, and the porosity is reduced. On the other hand, graphite itself is conductive, and can achieve resistivity performance closer to that of pure copper.

[0104] A third aspect of the present invention provides a solar cell, comprising a metal electrode, wherein the metal electrode is prepared using the electrode slurry described in the first aspect of the present invention, or is prepared using the method described in the second aspect of the present invention.

[0105] For example, the solar cell is a silicon solar cell, specifically a monocrystalline silicon solar cell, a polycrystalline silicon thin film solar cell, and an amorphous silicon thin film solar cell. It can also be other types of solar cells, as long as the metal electrode of the solar cell is obtained by the preparation method provided by the present invention, it is within the protection scope of the present invention.

[0106] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0107] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0108] The present invention is described in detail below in conjunction with specific embodiments, which are used to understand but not to limit the present invention.

[0109] Example 1

[0110] An electrode slurry is obtained by the following preparation method:

[0111] (1) dissolving 20% ​​polyurethane resin into 60% dipropylene glycol methyl ether acetate, and heating at a constant temperature of 70-80° C. to obtain a completely dissolved organic system A;

[0112] (2) Graphite powder and copper oxide powder are added to organic system A and mixed to prepare electrode slurry, wherein the mass ratio of graphite powder to copper oxide powder is 2:1; the D50 of graphite powder is 60nm-500nm, and the D50 of copper oxide powder is 60nm-500nm.

[0113] Example 2

[0114] An electrode slurry is obtained by the following preparation method:

[0115] (1) dissolving 20% ​​epoxy resin into 80% diethylene glycol butyl ether acetate, and heating at a constant temperature of 70-80° C. to obtain a completely dissolved organic system B;

[0116] (2) adding graphene powder and cuprous oxide powder to organic system B and mixing to prepare electrode slurry, wherein the mass ratio of graphene powder to cuprous oxide powder is 3:1; the D50 of graphene powder is 60nm-500nm, and the D50 of cuprous oxide powder is 60nm-500nm.

[0117] Example 3

[0118] An electrode slurry is obtained by the following preparation method:

[0119] (1) dissolving 20% ​​epoxy resin into 60% dipropylene glycol methyl ether acetate, and heating at a constant temperature of 70-80° C. to obtain a completely dissolved organic system C;

[0120] (2) Graphite powder, copper oxide powder and cuprous oxide powder are added to organic system C and mixed to prepare an electrode slurry, wherein the mass ratio of graphene powder, copper oxide powder and cuprous oxide powder is 1:0.9:0.1; the D50 of the graphene powder is 60nm-500nm, the D50 of the copper oxide powder is 60nm-500nm, and the D50 of the cuprous oxide powder is 60nm-500nm.

[0121] Example 4

[0122] The process is carried out with reference to Example 1, except that the components involved in the reaction in step (2) are a mixture of graphite powder, copper oxide powder and cuprous oxide powder, and the mass ratio of the three is 2:0.5:0.5; and the D50 of the cuprous oxide powder is 60nm-500nm.

[0123] Example 5

[0124] The process is carried out in accordance with Example 1, except that the mass ratio of graphite powder to copper oxide powder is 5:1.

[0125] Embodiment 6-10

[0126] A method for preparing a solar cell copper grid electrode comprises the following steps:

[0127] (1) In Examples 6-10, the electrode slurries provided in Examples 1-5 were coated on the silicon substrate of the solar cell respectively, with a coating thickness of 10 μm;

[0128] (2) Scanning the slurry on the substrate surface with a nanosecond (femtosecond) laser, with the following laser setting parameters: pulse frequency 2000 kHz, pulse energy 490 nJ, laser wavelength 530 nm, pulse width <15 ps, scanning speed 4 mm / s;

[0129] (3) After the reaction is completed, the substrate is rinsed with clean water to remove the remaining slurry to obtain a copper grid electrode.

[0130] Comparative Example 1

[0131] A method for preparing a solar cell copper grid electrode comprises the following steps:

[0132] (1) preparing ink with copper oxide powder, reducing agent ethylene glycol (EG) and dispersant polyvinyl pyrrolidone (PVP), wherein the mass ratio of copper oxide powder to reducing agent is 2:1, and the mass ratio of copper oxide powder to PVP is 3:1; and D50 of copper oxide powder is 60nm-500nm;

[0133] (2) applying the ink onto a silicon substrate of a solar cell by coating, with a coating thickness of 10 μm;

[0134] (3) Scanning the slurry on the surface of the substrate with a nanosecond (femtosecond) laser, with the following laser setting parameters: pulse frequency 2000 kHz, pulse energy 490 nJ, laser wavelength 530 nm, pulse width <15 ps, scanning speed 4 mm / s;

[0135] (4) After the reaction is completed, the substrate is rinsed with clean water to remove the remaining ink to obtain a copper grid electrode.

[0136] Test Case

[0137] (1) The porosity of the metal electrodes obtained by testing the above Examples 6-10 and Comparative Example 1 was measured and calculated using a metallographic microscope. The results are recorded in Table 1.

[0138] (2) The resistivity of the metal electrodes obtained in the above embodiments and comparative examples was measured using a resistance meter, and the results are recorded in Table 1.

[0139] Table 1

[0140]

[0141]

[0142] It can be seen from the data in Table 1 that the porosity of the metal electrodes prepared in the present invention is within 5%, the density of the electrodes is good, and the resistivity of the metal electrodes is improved.

[0143] By comparing the results of Comparative Example 1 and Examples 6-10, it can be seen that the metal electrode prepared in the present invention has the advantages of low porosity and low resistivity.

[0144] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrode slurry, characterized in that: It is composed of a metal oxide, a solid reducing agent and an organic system; the metal oxide is one or both of copper oxide and cuprous oxide; The solid reducing agent is graphite and / or graphene; the mass ratio of the metal oxide to the solid reducing agent is 1:(1-3); The organic system consists of a base resin and a diluent; The matrix resin is selected from at least one of polyurethane resin, epoxy resin, acrylic resin and polyether resin; the diluent is selected from at least one of dipropylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, ethyl acetate and butyl acetate; The D50 of the metal oxide is 50nm~1000nm; the D50 of the solid reducing agent is 50nm~1000nm; The preparation method of the organic system comprises the following steps: bringing the base resin and the diluent into first contact at 50-90° C.; the mass ratio of the base resin to the diluent is 1:(1-6).

2. The electrode slurry according to claim 1, characterized in that: The concentration of the matrix resin is 15wt% to 50wt%; And / or, the concentration of the diluent is 50wt%~80wt%.

3. A method for preparing a metal electrode, characterized in that: The metal electrode is prepared by using the electrode slurry and laser process described in claim 1 or 2.

4. The method according to claim 3, characterized in that The metal electrode is a metal electrode in a solar cell, a secondary battery, a circuit board, a light emitting diode or a microelectronic device.

5. The method according to claim 3, characterized in that: The metal electrode is a grid line electrode of a solar cell.

6. A solar cell comprising a metal electrode, characterized in that: The metal electrode is prepared by using the electrode slurry according to claim 1 or 2, or by using the method according to any one of claims 3 to 5.

Images