Water-based soldering flux for photovoltaic N-type battery 0BB assembly and preparation method of water-based soldering flux

Abstract

The invention belongs to the technical field of water-based soldering flux manufacturing, and particularly relates to a water-based soldering flux for a photovoltaic N-type battery 0BB assembly and a preparation method of the water-based soldering flux. Deionized water, an alcohol solvent, a high-boiling-point solvent, organic acid, a fluoride-free surfactant, an antioxidant and a composite corrosion inhibitor are compounded to obtain the water-based soldering flux. Deionized water is used as a main solvent, and a high-boiling-point solvent is added, so that continuous wettability in the welding process is kept; the organic acid can remove metal surface oxides and reduce the surface tension of the solder; the fluoride-free surfactant has wettability and environmental friendliness, residues after welding are reduced, and the welding strength is improved; the composite corrosion inhibitor is compounded by the polysaccharide extract and the corrosion inhibition component, the metal oxidation process can be inhibited, the polysaccharide extract promotes formation of a protective film, and secondary oxidation in the welding process is prevented; the water-based soldering flux for the photovoltaic N-type battery 0BB assembly is applied to the 0BB assembly, and the welding strength and the alloying degree of a fine grid are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of water-based soldering flux manufacturing, and in particular relates to a water-based soldering flux for a photovoltaic N-type battery 0BB component and a preparation method thereof. Background Art

[0002] With the continuous advancement of photovoltaic cell technology, N-type TOPCon and HJT technologies have emerged, and N-type modules are increasingly replacing PERC modules. In recent years, the surge in international silver prices has brought unprecedented cost concerns to photovoltaic cells and modules. To reduce module manufacturing costs, major module manufacturers have successively launched N-type OBB modules. OBB refers to cells with no main grid, but instead fine grids. This reduces silver paste usage and increases current collection, but also presents significant challenges for soldering. Traditional module soldering processes are no longer compatible with OBB modules, posing significant challenges for manufacturers of auxiliary materials and equipment involved in the soldering process, particularly flux manufacturers. Traditional alcohol-based fluxes significantly impact the soldering process of OBB modules, specifically affecting the tensile strength of the adhesive after curing, poor alloying of the fine grids, and resulting in cold solder joints. Due to their low boiling point and rapid volatilization, alcohol-based fluxes rapidly crystallize during the actual soldering process, resulting in excessive crystallization. The increased acid content also affects the cure rate of the thermosetting adhesive.

[0003] Chinese invention patent publication number CN119216873B discloses a photovoltaic water-based solder flux, its preparation method, and application. The flux comprises the following raw materials, in parts by weight: 1-5 parts cosolvent, 0.1-3 parts wetting agent, 0.1-3 parts polyethylene glycol, 1-8 parts activator microcapsules, and 0.1-1 part antioxidant, with water making up the total to 100 parts. The activator microcapsules comprise a core and a material surrounding the core, the core being a composite activator. The composite activator is a combination of an organic acid and a protective agent; the organic acid is a combination of 3-hydroxy-2-naphthoic acid, oleic acid, and methylsuccinic acid; and the protective agent is a combination of trimethylsiloxane and a quaternary ammonium salt cationic fluorocarbon surfactant. The flux uses water as the primary solvent and is particularly suitable for preparing photovoltaic cell modules with hot soldering temperatures of 150-230°C. The flux maintains its activity during the soldering process. However, the existing technology has not conducted further research on surfactant and corrosion inhibitor components to solve the technical problems of the influence of traditional flux on the tension of thermosetting adhesive and alloying of fine grid in the 0BB assembly. Summary of the Invention

[0004] The purpose of the present invention is to provide a water-based flux for photovoltaic N-type battery 0BB components and a preparation method thereof, so as to solve the technical problems in the prior art of the influence of traditional flux on the tensile force of thermosetting adhesive and alloying of fine grids when applied in 0BB components.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] Photovoltaic N-type cell 0BB module water-based flux is prepared from the following components in parts by weight:

[0007] 30-60 parts of deionized water, 30-50 parts of alcohol solvent, 2-8 parts of high boiling point solvent, 1-4 parts of organic acid, 0.1-1 part of fluorine-free surfactant, 0.1-1 part of antioxidant and 0.1-1 part of composite corrosion inhibitor.

[0008] The alcohol solvent is isopropyl alcohol; the high-boiling-point solvent is any one or more combinations of diethylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol dimethyl ether, and ethylene glycol butyl ether; the organic acid is any one or more combinations of acetic acid, malic acid, malonic acid, citric acid, glutaric acid, and tartaric acid; and the antioxidant is one or both of ascorbic acid and 2,4,6-tris(dimethylaminomethyl)phenol.

[0009] Preferably, the preparation method of the fluorine-free surfactant comprises the following steps:

[0010] S11. Add 250-300 parts by mass of dehydroabietyl alcohol to a reactor, heat and stir, add 80-140 parts of ethylene oxide and 1-5 parts of sodium hydroxide, and react until the pressure in the reactor no longer decreases to obtain rosin-based polyoxyethylene ether, then add 90-110 parts of epichlorohydrin and 3-5 parts of boron trifluoride catalyst, raise the temperature to 60-70° C. and react for 6-8 hours, perform vacuum distillation, add 35-45 parts of a 40-50 wt% sodium hydroxide aqueous solution, stir, raise the temperature to 40-50° C. and react for 4-6 hours, and wash to obtain rosin-based polyoxyethylene glycidyl ether;

[0011] S12, adding 40-60 parts of cardanol to 40-60 parts of dimethyl sulfoxide solvent by mass, adding 60-80 parts of rosin-based polyoxyethylene glycidyl ether and 1-5 parts of tin tetrachloride catalyst under stirring, raising the temperature to 60-65° C. and reacting for 0.5-1 hour to prepare a rosin-based surfactant;

[0012] S13. Mix 1-2 parts by mass of a rosin-based surfactant and 1-2 parts by mass of a nonionic surfactant to prepare a fluorine-free surfactant.

[0013] Preferably, the preparation principle of the rosin-based surfactant is as follows:

[0014]

[0015] Preferably, the molar ratio of dehydroabietyl alcohol to ethylene oxide in S11 is 1:2-3, and the mixture is heated to 60-65° C. and stirred for 1-2 hours before adding ethylene oxide dropwise, and the addition is completed within 1-2 hours.

[0016] Preferably, the washing operation in S11 is washing with a saturated sodium chloride aqueous solution until neutral, standing for phase separation, and adding anhydrous sodium sulfate to the organic phase to remove water to obtain rosin-based polyoxyethylene glycidyl ether.

[0017] Preferably, the nonionic surfactant in S13 is any one or more combinations of alkyl glycoside surfactants and alkylphenol polyoxyethylene ether surfactants.

[0018] Preferably, the alkyl glycoside surfactant is any one of lauryl glucoside, myristyl glucoside and octyl glucoside.

[0019] Preferably, the alkylphenol polyoxyethylene ether surfactant is any one of OP-9, OP-10 and OP-15.

[0020] Preferably, the preparation method of the composite corrosion inhibitor comprises the following steps:

[0021] S21. Place gallnuts in a grinder, crush and sieve to obtain gallnut powder, add 80-100 parts of the gallnut powder to petroleum ether at a material-liquid mass ratio of 1:20-30, heat to 60-70°C to remove impurities for 1-2 hours, filter and collect the solid, dry, add to deionized water at a material-liquid mass ratio of 1:20-30, heat to 80-90°C, extract for 1-2 hours, and collect the liquid by centrifugation to obtain a polysaccharide extract;

[0022] S22, evaporating and concentrating 500-1000 parts of the polysaccharide extract to 200-300 parts by mass, centrifuging, taking the supernatant and letting it stand for 12-18 hours, collecting the flocculent material in the lower layer, drying and grinding it to obtain a polysaccharide extract;

[0023] S23. Mix 1-2 parts of the polysaccharide extract and 1-4 parts of the corrosion inhibition component by mass to prepare a composite corrosion inhibitor.

[0024] Preferably, in S21, the product is crushed through an 80-100 mesh sieve and centrifuged at a speed of 3000-5000 r / min for 5-10 min.

[0025] Preferably, in S22, the supernatant is taken out by centrifugation at a speed of 3000-5000 r / min for 5-10 min, and the flocculent material in the lower layer is dried at 60-65° C. and ground to pass through an 80-100 mesh sieve.

[0026] Preferably, the corrosion inhibition component in S23 is one or both of triethanolamine and benzotriazole.

[0027] A method for preparing a water-based flux for a photovoltaic N-type cell 0BB component comprises the following steps:

[0028] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0029] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. The present invention obtains a water-based soldering flux by compounding deionized water, an alcohol solvent, a high-boiling-point solvent, an organic acid, a fluorine-free surfactant, an antioxidant and a composite corrosion inhibitor. Deionized water is used as the main solvent, and the addition of a high-boiling-point solvent maintains continuous wettability during the welding process; the organic acid can remove oxides on the metal surface and reduce the surface tension of the solder; the fluorine-free surfactant does not contain fluorocarbon substances, has both wettability and environmental protection, reduces post-weld residue and improves welding strength; the composite corrosion inhibitor is compounded by a polysaccharide extract and a corrosion-inhibiting component, which can inhibit the metal oxidation process, and the polysaccharide extract can promote the formation of a protective film to prevent secondary oxidation during the welding process; the water-based soldering flux of the photovoltaic N-type battery 0BB component prepared by the present invention is used in the 0BB component, which improves the welding strength and the alloying degree of the fine grid.

[0032] 2. The present invention prepares rosin-based polyoxyethylene ether by using dehydroabietyl alcohol and ethylene oxide, and then grafts epoxy groups with epichlorohydrin and reacts with cardanol to prepare a rosin-based surfactant. The polyoxyethylene groups contained in the rosin-based surfactant improve water solubility and can effectively reduce the surface tension of the flux. When compounded with a nonionic surfactant, the water-based flux has excellent wettability and stability, and does not contain fluorocarbon surfactant components, so it is environmentally friendly.

[0033] 3. The composite corrosion inhibitor prepared by the present invention by extracting and purifying the polysaccharide extract of gallnut by removing impurities and then compounding it with corrosion-inhibiting components can inhibit the metal oxidation process. The elements such as N and O contained in the polysaccharide extract of gallnut have lone electron pairs, which can form coordination bonds with metals and form nano-scale protective films on the surface to prevent secondary oxidation during welding. The polysaccharide extract reduces the amount of corrosion-inhibiting components while maintaining the corrosion inhibition effect unchanged, thereby improving the utilization rate of the corrosion-inhibiting components. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of 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 making any creative efforts are within the scope of protection of the present invention.

[0035] Example 1: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 34.5 g of deionized water, 50 g of alcohol solvent, 3 g of high boiling point solvent, 2 g of organic acid, 0.3 g of fluorine-free surfactant, 0.1 g of antioxidant and 0.1 g of composite corrosion inhibitor.

[0036] The alcohol solvent is isopropyl alcohol, the high-boiling point solvent is diethylene glycol butyl ether; the organic acid is prepared by mixing acetic acid, malic acid, malonic acid, citric acid and glutaric acid in a mass ratio of 1:1:1:1:1; and the antioxidant is ascorbic acid.

[0037] The preparation method of the fluorine-free surfactant of this embodiment comprises the following steps:

[0038] S11, adding 286g of dehydroabietyl alcohol to a reactor, heating and stirring, adding 90g of ethylene oxide and 5g of sodium hydroxide to react until the pressure in the reactor no longer decreases, to obtain rosin-based polyoxyethylene ether, then adding 95g of epichlorohydrin and 4g of boron trifluoride catalyst, heating to 60°C and reacting for 6h, distilling under reduced pressure, adding 40g of 40wt% sodium hydroxide aqueous solution, stirring and heating to 40°C and reacting for 5h, washing with saturated sodium chloride aqueous solution until neutral, standing for phase separation, taking the organic phase and adding 20g of anhydrous sodium sulfate to remove water, to obtain rosin-based polyoxyethylene glycidyl ether;

[0039] S12, adding 55g of cardanol to 50g of dimethyl sulfoxide solvent, adding 70g of rosin-based polyoxyethylene glycidyl ether and 3g of tin tetrachloride catalyst under stirring, heating to 60°C and reacting for 0.5h to obtain a rosin-based surfactant;

[0040] S13. Mix 2 g of a rosin-based surfactant, 1 g of OP-10, and 1 g of lauryl glucoside to prepare a fluorine-free surfactant.

[0041] The preparation method of the composite corrosion inhibitor of this embodiment comprises the following steps:

[0042] S21. Place the gallnuts in a grinder and grind them through an 80-mesh sieve to obtain gallnut powder. Add 100 g of the gallnut powder to 2 kg of petroleum ether, heat the mixture to 60° C. to remove impurities for 1 hour, filter and collect the solid, dry it, add it to 2 kg of deionized water, heat the mixture to 90° C. to extract for 2 hours, centrifuge it at 5000 rpm for 10 minutes, and filter and collect the liquid to obtain a polysaccharide extract.

[0043] S22, evaporating and concentrating 1000 g of the polysaccharide extract to 300 g, centrifuging at 5000 r / min for 10 min, taking the supernatant and letting it stand for 18 h, collecting the flocculent material at the lower layer, drying it at 60° C., and grinding it through an 80-mesh sieve to obtain a polysaccharide extract;

[0044] S23. Mix 1 g of the polysaccharide extract, 1 g of triethanolamine, and 2 g of benzotriazole to prepare a composite corrosion inhibitor.

[0045] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0046] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0047] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0048] Example 2: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 45.95 g of deionized water, 48 g of alcohol solvent, 3 g of high boiling point solvent, 2.5 g of organic acid, 0.35 g of fluorine-free surfactant, 0.1 g of antioxidant and 0.1 g of composite corrosion inhibitor.

[0049] The alcohol solvent is isopropyl alcohol, the high-boiling point solvent is tripropylene glycol butyl ether; the organic acid is prepared by mixing acetic acid, malic acid, malonic acid and tartaric acid in a mass ratio of 1:1:1:1:1; and the antioxidant is ascorbic acid.

[0050] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0051] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0052] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0053] The difference between the fluorine-free surfactant of this embodiment and that of Example 1 is that in step S13, 2 g of rosin-based surfactant and 1 g of octyl glucoside are mixed to prepare the fluorine-free surfactant.

[0054] The preparation method of the composite corrosion inhibitor of this embodiment is the same as that of Example 1.

[0055] Example 3: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 48.9 g of deionized water, 45 g of alcohol solvent, 3.5 g of high boiling point solvent, 2 g of organic acid, 0.35 g of fluorine-free surfactant, 0.1 g of antioxidant and 0.15 g of composite corrosion inhibitor.

[0056] The alcohol solvent is isopropyl alcohol, the high-boiling point solvent is propylene glycol methyl ether; the organic acid is prepared by mixing malic acid, malonic acid, citric acid and glutaric acid in a mass ratio of 2:1:1:1; and the antioxidant is 2,4,6-tris(dimethylaminomethyl)phenol.

[0057] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0058] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0059] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0060] The difference between the fluorine-free surfactant of this embodiment and that of Example 1 is that in step S13, 1 g of a rosin-based surfactant, 1 g of OP-10, and 1 g of OP-15 are mixed to prepare the fluorine-free surfactant.

[0061] The preparation method of the composite corrosion inhibitor of this embodiment is the same as that of Example 1.

[0062] Example 4: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 49 g of deionized water, 45 g of alcohol solvent, 3 g of high boiling point solvent, 2.5 g of organic acid, 0.3 g of fluorine-free surfactant, 0.1 g of antioxidant and 0.1 g of composite corrosion inhibitor.

[0063] The alcohol solvent is isopropyl alcohol, the high boiling point solvent is ethylene glycol dimethyl ether; the organic acid is prepared by mixing malonic acid, citric acid, glutaric acid and tartaric acid in a mass ratio of 1:2:1:1; and the antioxidant is ascorbic acid.

[0064] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0065] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0066] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0067] The preparation method of the fluorine-free surfactant in this embodiment is the same as that in Example 1.

[0068] The difference between the composite corrosion inhibitor of this embodiment and that of Example 1 is that in step S23, 1 g of the polysaccharide extract and 1 g of benzotriazole are mixed to prepare the composite corrosion inhibitor.

[0069] Example 5: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 59.6 g of deionized water, 30 g of alcohol solvent, 5 g of high boiling point solvent, 3.5 g of organic acid, 0.5 g of fluorine-free surfactant, 0.8 g of antioxidant and 0.6 g of composite corrosion inhibitor.

[0070] The alcohol solvent is isopropyl alcohol, the high-boiling-point solvent is ethylene glycol butyl ether; the organic acid is prepared by mixing acetic acid, malonic acid and glutaric acid in a mass ratio of 1:1:1; and the antioxidant is prepared by mixing ascorbic acid and 2,4,6-tris(dimethylaminomethyl)phenol in a mass ratio of 1:1.

[0071] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0072] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0073] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0074] The preparation method of the fluorine-free surfactant in this embodiment is the same as that in Example 1.

[0075] The difference between the composite corrosion inhibitor of this embodiment and that of Example 1 is that in step S23, 1 g of polysaccharide extract and 1 g of triethanolamine are mixed to prepare the composite corrosion inhibitor.

[0076] Example 6: The water-based flux for the photovoltaic N-type cell 0BB component of this embodiment is prepared from the following components: 43.8 g of deionized water, 45 g of alcohol solvent, 7 g of high boiling point solvent, 1.9 g of organic acid, 0.8 g of fluorine-free surfactant, 0.7 g of antioxidant and 0.8 g of composite corrosion inhibitor.

[0077] The alcohol solvent is isopropyl alcohol, the high boiling point solvent is prepared by mixing diethylene glycol butyl ether and tripropylene glycol butyl ether in a mass ratio of 1:1; the organic acid is prepared by mixing malic acid, citric acid and tartaric acid in a mass ratio of 1:1:1; and the antioxidant is ascorbic acid.

[0078] The method for preparing a water-based soldering flux for a photovoltaic N-type cell OBB assembly of this embodiment includes the following steps:

[0079] S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent;

[0080] S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

[0081] The difference between the fluorine-free surfactant of this embodiment and that of Example 1 is that in step S13, 1 g of a rosin-based surfactant, 1 g of myristyl glucoside, and 1 g of OP-9 are mixed to prepare the fluorine-free surfactant.

[0082] The difference between the composite corrosion inhibitor of this embodiment and that of Example 1 is that in step S23, 1 g of the polysaccharide extract and 1 g of benzotriazole are mixed to prepare the composite corrosion inhibitor.

[0083] Comparative Example 1: The difference between this comparative example and Example 1 is that no rosin-based surfactant is added to the fluorine-free surfactant.

[0084] Comparative Example 2: This comparative example differs from Example 1 in that deionized water is replaced with isopropyl alcohol.

[0085] Comparative Example 3: This comparative example differs from Example 1 in that the fluorine-free surfactant is replaced by a fluorocarbon surfactant, and the deionized water is replaced by isopropyl alcohol.

[0086] Comparative Example 4: The difference between this comparative example and Example 1 is that no polysaccharide extract is added to the composite corrosion inhibitor.

[0087] Comparative Example 5: The difference between this comparative example and Example 1 is that the polysaccharide extract is not added to the composite corrosion inhibitor and the deionized water is replaced by isopropyl alcohol.

[0088] Performance Testing

[0089] The water-based soldering flux prepared in each embodiment and comparative example was used to solder the cell grids and PAD points on the 0BB module, and the tensile force of the front and back glue points was measured using a horizontal tensile tester.

[0090] The welded cell grids and PAD points are sent to relevant institutions to test their front and back side pass rates, alloy ratios and component A-grade rates.

[0091] Table 1 is the standard performance data of 0BB components:

[0092] Table 1 Standard performance data

[0093]

[0094] The test results are shown in Table 2 below:

[0095] Table 2 Test results

[0096]

[0097] It can be seen from the data in the above table that the water-based flux prepared in Examples 1 to 6 is used for the front glue point pull on the 0BB component between 0.35 and 0.41N, and the back glue point pull is between 0.31 and 0.36N, indicating that the water-based flux prepared in the present invention has excellent welding strength for 0BB component welding. In Comparative Example 3, the fluorine-free surfactant is replaced by a fluorocarbon surfactant, and the deionized water is replaced by isopropyl alcohol. Therefore, the flux evaporates too quickly during the welding process and crystallizes quickly. The surface tension of the fluorocarbon surfactant is lower than that of the fluorine-free surfactant, resulting in a front glue point pull of 0.07N and a back glue point pull of 0.09N, which are much lower than the data of each embodiment; the water-based flux prepared in Examples 1 to 6 is used for the front and back surfaces of the 0BB component with a qualified rate of 97.16 to 9 8.98%, the alloy ratio is between 98.05 and 98.89%, and the component A-grade product rate is between 99.57 and 99.66%, indicating that the water-based flux prepared by the present invention can be used on 0BB components to improve the alloying degree of the fine grid and meet the production application requirements. The composite corrosion inhibitor of Example 4 does not add polysaccharide extract, resulting in a positive and back side qualified rate of 86.35%, an alloy ratio of 87.59%, and a component A-grade product rate of 90.74%. The composite corrosion inhibitor of Comparative Example 5 does not add polysaccharide extract and replaces deionized water with isopropanol, resulting in a positive and back side qualified rate of 61.99%, an alloy ratio of 76.38%, and a component A-grade product rate of 70.34%, indicating that the polysaccharide extract can prevent premature oxidation of the metal and has the performance of improving the alloying degree of the fine grid.

[0098] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0099] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Water-based flux for photovoltaic N-type cell 0BB components, characterized in that: It is prepared from the following components in parts by mass: 30-60 parts of deionized water, 30-50 parts of alcohol solvent, 2-8 parts of high boiling point solvent, 1-4 parts of organic acid, 0.1-1 part of fluorine-free surfactant, 0.1-1 part of antioxidant and 0.1-1 part of composite corrosion inhibitor.

2. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 1, characterized in that: The alcohol solvent is isopropyl alcohol; the high-boiling-point solvent is any one or more combinations of diethylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol dimethyl ether, and ethylene glycol butyl ether; the organic acid is any one or more combinations of acetic acid, malic acid, malonic acid, citric acid, glutaric acid, and tartaric acid; and the antioxidant is one or both of ascorbic acid and 2,4,6-tris(dimethylaminomethyl)phenol.

3. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 1, characterized in that: The preparation method of the fluorine-free surfactant comprises the following steps: S11. Add 250-300 parts by mass of dehydroabietyl alcohol to a reactor, heat and stir, add 80-140 parts of ethylene oxide and 1-5 parts of sodium hydroxide, and react until the pressure in the reactor no longer decreases to obtain rosin-based polyoxyethylene ether, then add 90-110 parts of epichlorohydrin and 3-5 parts of boron trifluoride catalyst, raise the temperature to 60-70° C. and react for 6-8 hours, perform vacuum distillation, add 35-45 parts of a 40-50 wt% sodium hydroxide aqueous solution, stir, raise the temperature to 40-50° C. and react for 4-6 hours, and wash to obtain rosin-based polyoxyethylene glycidyl ether; S12, adding 40-60 parts of cardanol to 40-60 parts of dimethyl sulfoxide solvent by mass, adding 60-80 parts of rosin-based polyoxyethylene glycidyl ether and 1-5 parts of tin tetrachloride catalyst under stirring, raising the temperature to 60-65° C. and reacting for 0.5-1 hour to prepare a rosin-based surfactant; S13. Mix 1-2 parts by mass of a rosin-based surfactant and 1-2 parts by mass of a nonionic surfactant to prepare a fluorine-free surfactant.

4. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 3, characterized in that: The molar ratio of dehydroabietyl alcohol to ethylene oxide in S11 is 1:2-3. The mixture is heated to 60-65° C. and stirred for 1-2 hours, and then ethylene oxide is added dropwise, and the addition is completed within 1-2 hours. The specific washing operation is washing with a saturated sodium chloride aqueous solution until neutral, standing for phase separation, and taking the organic phase and adding anhydrous sodium sulfate to remove water to obtain rosin-based polyoxyethylene glycidyl ether.

5. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 3, characterized in that: The nonionic surfactant in S13 is any one or more combinations of alkyl glycoside surfactants and alkylphenol polyoxyethylene ether surfactants, the alkyl glycoside surfactant is any one of lauryl glucoside, myristyl glucoside, and octyl glucoside, and the alkylphenol polyoxyethylene ether surfactant is any one of OP-9, OP-10, and OP-15.

6. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 1, characterized in that: The preparation method of the composite corrosion inhibitor comprises the following steps: S21. Place gallnuts in a grinder, crush and sieve to obtain gallnut powder, add 80-100 parts of the gallnut powder to petroleum ether at a material-liquid mass ratio of 1:20-30, heat to 60-70°C to remove impurities for 1-2 hours, filter and collect the solid, dry, add to deionized water at a material-liquid mass ratio of 1:20-30, heat to 80-90°C, extract for 1-2 hours, and collect the liquid by centrifugation to obtain a polysaccharide extract; S22, evaporating and concentrating 500-1000 parts of the polysaccharide extract to 200-300 parts by mass, centrifuging, taking the supernatant and letting it stand for 12-18 hours, collecting the flocculent material in the lower layer, drying and grinding it to obtain a polysaccharide extract; S23. Mix 1-2 parts of the polysaccharide extract and 1-4 parts of the corrosion inhibition component by mass to prepare a composite corrosion inhibitor.

7. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 5, characterized in that: In the step S21, the product is crushed through an 80-100 mesh sieve and centrifuged at a speed of 3000-5000 r / min for 5-10 minutes. In the step S22, the product is centrifuged at a speed of 3000-5000 r / min for 5-10 minutes to obtain the supernatant, and the flocculent material in the lower layer is dried at 60-65° C. and ground through an 80-100 mesh sieve.

8. The water-based soldering flux for photovoltaic N-type cell OBB assembly according to claim 5, characterized in that The corrosion inhibition component in S23 is one or both of triethanolamine and benzotriazole.

9. A method for preparing a water-based flux for photovoltaic N-type cell OBB components, characterized in that: The steps include: S1. Add deionized water, alcohol solvent, high boiling point solvent and organic acid into a stirring container in sequence and stir until clear and transparent; S2. Add the fluorine-free surfactant, antioxidant and composite corrosion inhibitor into the stirring container and stir evenly to obtain a water-based soldering flux for the photovoltaic N-type cell 0BB component.

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