A flux material for photovoltaic modules, a preparation method thereof, and a string welding composite lamination welding process

Abstract

This application belongs to the field of photovoltaic welding technology, specifically providing a flux material for photovoltaic modules, its preparation method, and a string-welding composite lamination process. The preparation method of the flux material for photovoltaic modules includes the following steps: A: reacting MAL-PEG-NH2 and 2-aldehyde phenylboronic acid to obtain a precursor, then reacting the precursor with a furan derivative to obtain an inhibitor; B: mixing the solvent and inhibitor evenly, then adding an activator, film-forming agent, surfactant, pH adjuster, antioxidant, corrosion inhibitor, and rheology modifier and mixing evenly to obtain the final product. The flux material for photovoltaic modules prepared in this application has the advantages of inhibiting the formation of interlayer IMC and improving welding strength.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic welding technology, and in particular relates to a welding flux material for photovoltaic modules and its preparation method, as well as a string welding composite lamination welding process. Background Technology

[0002] The photovoltaic (PV) module cell welding process involves connecting individual solar cells in series to form a cell string, which is the basic component of a solar panel. The conversion efficiency of a solar panel depends on its electrical performance, while the performance of the cell string is affected by the welding quality of the individual cells and the string itself.

[0003] Flux plays a crucial role in photovoltaic welding processes, removing oxides, preventing re-oxidation, reducing surface tension, and promoting solder wetting and spread. Currently, fluxes can be categorized by composition into organic, inorganic, and hybrid organic-inorganic fluxes; by activity into highly active, moderately active, and weakly active fluxes; and by cleaning method into solvent-cleaning, water-cleaning, and no-clean fluxes.

[0004] With the continuous improvement of photovoltaic module performance requirements, technicians have deepened their research on fluxes. For example, patent application CN107322188A discloses a flux for photovoltaic welding strips, comprising zinc chloride, ammonium chloride, hydroxy acid, citric acid, triisopropanolamine, dibutylamine, hexadecyltrimethylammonium bromide, acrylic resin, silicone-modified acrylic resin, sorbitol, triethanolamine, humectant, and deionized water. The components of this flux, calculated by mass percentage, include the following: zinc chloride, ammonium chloride, hydroxy acid, citric acid, triisopropanolamine, dibutylamine, hexadecyltrimethylammonium bromide, acrylic resin, silicone-modified acrylic resin, sorbitol, triethanolamine, humectant, and the remainder is deionized water. Through this method, the flux reduces the surface tension of the solder, improves wettability, reduces post-weld slag, and improves the quality of photovoltaic welding.

[0005] For example, patent application CN116493808A discloses a water-based flux for welding photovoltaic cells, comprising the following raw materials in weight percentages: 0.5-2% activator, 0.05-1% surfactant, 0.05-0.2% corrosion inhibitor, 1-5% additive, 0.1-0.5% defoamer, and 92-99% deionized water. This flux improves the deoxidation welding fluxing ability, reduces residual crystallization, improves the working efficiency of photovoltaic module factories, and lowers the raw material cost of products, thus contributing to the profitability of photovoltaic module factories.

[0006] The flux used in the aforementioned photovoltaic welding process has a weak inhibitory effect on the growth of intermetallic compounds (IMCs) during welding, resulting in significant atomic migration at the interface between the substrate and the solder. Therefore, improving the flux's ability to inhibit the growth of intermetallic compounds during welding is an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned issues and further suppress IMC growth and interface atomic migration during the photovoltaic module welding process, this application provides a flux material for photovoltaic modules, its preparation method, and a string-welding composite lamination welding process.

[0008] This application first provides a method for preparing a flux material for photovoltaic modules, comprising the following steps:

[0009] A: A precursor was prepared by reacting MAL-PEG-NH2 and 2-aldehyde phenylboronic acid, and then the precursor was reacted with a furan derivative to prepare an inhibitor.

[0010] B: Mix the solvent and inhibitor evenly, then add the activator, film-forming agent, surfactant, pH adjuster, antioxidant, corrosion inhibitor, and rheology modifier and mix evenly to obtain the final product.

[0011] Furthermore, in step A, the molar ratio of MAL-PEG-NH2 to 2-aldehyde phenylboronic acid is 1:(2-2.5).

[0012] Furthermore, in step A, the mass ratio of the precursor to the furan derivative is (5-10):1.

[0013] Furthermore, in step A, the n of the PEG chain in the MAL-PEG-NH2 molecule is less than 6000.

[0014] Furthermore, in step A, the furan derivative is prepared by reacting phenylphosphodichloro with furfurylamine.

[0015] Furthermore, in step B, the solvent is one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, tetrahydrofurfural, glycerol, diethylene glycol, and ethanol.

[0016] And / or, in step B, the activator is one or more of the following: methylsuccinic acid, DL-malic acid, lactic acid, oxalic acid, sebacic acid, azelaic acid, citric acid, salicylic acid, palmitic acid, adipic acid, benzoic acid, and stearic acid;

[0017] And / or, in step B, the film-forming agent is a rosin-based film-forming agent;

[0018] And / or, in step B, the surfactant is a nonionic surfactant;

[0019] And / or, in step B, the antioxidant is a phenolic antioxidant;

[0020] And / or, in step B, the corrosion inhibitor is benzotriazole;

[0021] And / or, in step B, the rheology modifier is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

[0022] This application provides a flux material for photovoltaic modules, which is prepared using the above-described preparation method.

[0023] This application also provides a serial welding composite lamination process, including the following steps:

[0024] S1: Install interconnecting strips on the welding machine;

[0025] S2: Apply photovoltaic module flux material evenly to the surface of the welded patterned battery or interconnect strip using coating equipment, and use hot air for initial curing;

[0026] And / or, using a coating device, uniformly apply silver paste, solder paste, or photovoltaic module soldering flux to the surface of the battery or interconnect strip, and use hot air for preliminary curing; the battery is one of HJT / Topcon / BC battery, perovskite battery, or HJT\Topcon perovskite tandem battery;

[0027] The flux material for the photovoltaic module is prepared using the above-described preparation method;

[0028] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding.

[0029] Furthermore, in step S1, the interconnecting strip is a SnPb-coated interconnecting strip or a SnPbBi-coated low-temperature interconnecting strip.

[0030] Furthermore, in step S3, the pre-welding is performed using infrared, hot air, or electromagnetic welding.

[0031] Compared with the prior art, this application has the following beneficial effects:

[0032] 1. The flux material of this application is a compound of various components including solvents, inhibitors, activators, film-forming agents, surfactants, pH adjusters, antioxidants, corrosion inhibitors, and rheology modifiers. It can undergo a physicochemical reaction with the substrate metal surface to form an adsorbent film with excellent wettability, thus wetting the metal surface. During the welding process, it can dissolve and remove oxides from the substrate surface and wet and spread with the solder, reducing the formation of intermetallic compounds, thereby improving welding strength and enhancing the performance of the photovoltaic module.

[0033] 2. The inhibitor in this application is prepared by first reacting MAL-PEG-NH2 with 2-aldehyde phenylboronic acid to obtain a precursor, which is then reacted with a furan derivative to construct a dynamic cross-linking network, thereby improving the adsorption effect of the adsorption membrane. During the welding process, as the temperature increases, the DA bonds in the dynamic cross-linking network break, and the dynamic cross-linking network disintegrates, further enhancing the wetting and spreading effect on the substrate metal surface. At the same time, it can also form a carbon skeleton structure, inhibiting and hindering atomic migration between the solder and the substrate metal, further reducing the formation of interlayer IMC and improving the welding strength. Attached Figure Description

[0034] Figure 1 The images show SEM images of the weld joint cross-sections of Examples 1-2 and Control Groups 1-2 of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] This application has conducted extensive experimental research on the wetting properties of flux and different mechanisms for inhibiting IMC formation. Specifically, this application provides a method for preparing a flux material for photovoltaic modules, including the following steps:

[0037] A: A precursor was prepared by reacting MAL-PEG-NH2 and 2-aldehyde phenylboronic acid, and then the precursor was reacted with a furan derivative to prepare an inhibitor.

[0038] B: Mix the solvent and inhibitor evenly, then add the activator, film-forming agent, surfactant, pH adjuster, antioxidant, corrosion inhibitor, and rheology modifier and mix evenly to obtain the final product.

[0039] Furthermore, in step A, the molar ratio of MAL-PEG-NH2 to 2-aldehyde phenylboronic acid is 1:(2-2.5).

[0040] Furthermore, in step A, the mass ratio of the precursor to the furan derivative is (5-10):1.

[0041] Furthermore, in step A, the n of the PEG chain in the MAL-PEG-NH2 molecule is less than 6000.

[0042] Furthermore, in step A, the furan derivative is prepared by reacting phenylphosphodichloro with furfurylamine.

[0043] In some specific embodiments, in step A, the molar ratio of MAL-PEG-NH2 to 2-aldehyde phenylboronic acid can be 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, or 1:2.5. More preferably, in general, a molar ratio of 1:2.2 for MAL-PEG-NH2 to 2-aldehyde phenylboronic acid in step A yields better experimental results.

[0044] In some specific embodiments, in step A, the mass ratio of the precursor to the furan derivative can be 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1. More preferably, under normal circumstances, a mass ratio of 6.5:1 for the precursor to the furan derivative in step A yields better experimental results.

[0045] In some specific embodiments, in step A, the n of the PEG chain in the MAL-PEG-NH2 molecule can be 400, 600, 800, 1000, 1200, 2000, 2500, or 3000. More preferably, under normal circumstances, when the n of the PEG chain in the MAL-PEG-NH2 molecule is 800, better experimental results can be obtained.

[0046] Furthermore, in step B, the solvent is one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, tetrahydrofurfural, glycerol, diethylene glycol, and ethanol.

[0047] And / or, in step B, the activator is one or more of the following: methylsuccinic acid, DL-malic acid, lactic acid, oxalic acid, sebacic acid, azelaic acid, citric acid, salicylic acid, palmitic acid, adipic acid, benzoic acid, and stearic acid;

[0048] And / or, in step B, the film-forming agent is a rosin-based film-forming agent;

[0049] And / or, in step B, the surfactant is a nonionic surfactant;

[0050] And / or, in step B, the antioxidant is a phenolic antioxidant;

[0051] And / or, in step B, the corrosion inhibitor is benzotriazole;

[0052] And / or, in step B, the rheology modifier is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

[0053] In some specific embodiments, under normal circumstances, when the organic acid in step B is composed of DL-malic acid and salicylic acid, better experimental results can be obtained. More preferably, in step B, the organic acid is composed of DL-malic acid and salicylic acid in a mass ratio of 5:3.

[0054] In some specific embodiments, the solvent used in step B is ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, or tetrahydrofurfural, which yields better results. More preferably, under normal circumstances, the experimental results are better when the solvent is ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, and tetrahydrofurfural in a mass ratio of 1:2:3:3.

[0055] In some specific embodiments, more preferably, in step B, the film-forming agent is rosin.

[0056] In some specific embodiments, more preferably, octylphenol polyoxyethylene ether is selected as the surfactant in step B, which yields better results.

[0057] In some specific embodiments, more preferably, hydroquinone is used as the antioxidant in step B to obtain better experimental results.

[0058] This application provides a flux material for photovoltaic modules, which is prepared using the above-described preparation method.

[0059] This application also provides a serial welding composite lamination process, including the following steps:

[0060] S1: Install interconnecting strips on the welding machine;

[0061] S2: Apply photovoltaic module flux material evenly to the surface of the welded patterned battery or interconnect strip using coating equipment, and use hot air for initial curing;

[0062] And / or, using a coating device, uniformly apply silver paste, solder paste, or photovoltaic module soldering flux to the surface of the battery or interconnect strip, and use hot air for preliminary curing; the battery is one of HJT / Topcon / BC battery, perovskite battery, or HJT\Topcon perovskite tandem battery;

[0063] The flux material for the photovoltaic module is prepared using the above-described preparation method;

[0064] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding.

[0065] Furthermore, in step S1, the interconnecting strip is a SnPb-coated interconnecting strip or a SnPbBi-coated low-temperature interconnecting strip.

[0066] Furthermore, in step S3, the pre-welding is performed using infrared, hot air, or electromagnetic welding.

[0067] Under normal circumstances, when SnPbBi coated low-temperature interconnecting strips are selected for the interconnecting strips in step S1, better technical results can be obtained.

[0068] Preferably, the photovoltaic module welding process of this application is applicable to the welding of OBBtopcon / HJT cells and XBC / perovskite cells.

[0069] Example 1

[0070] The method for preparing the flux material for photovoltaic modules in this embodiment includes the following steps:

[0071] A: Add 100 mL of anhydrous ethanol, 0.05 mol of MAL-PEG-NH2 (the n of the PEG chain is 800), and 0.11 mol of 2-aldehyde phenylboronic acid to a 500 mL four-necked flask equipped with a stirrer, thermometer, dropping funnel, and condenser. After mixing well, add sodium borohydride and a small amount of PBS buffer solution. React at room temperature under nitrogen protection to obtain the precursor.

[0072] Then, in a round-bottom flask, 5g of the precursor and 0.77g of the furan derivative (5-hydroxymethylfurfural) were dissolved in 150mL of anhydrous ethanol, a Lewis acid catalyst was added, and the mixture was refluxed for 5h to prepare the inhibitor.

[0073] B: Take 45g of solvent (composed of 5g ethylene glycol monobutyl ether, 10g propylene glycol methyl ether, 15g tetrahydrofurfuryl alcohol, and 15g n-octanol), 2g of inhibitor, mix well, then add 8g of activator (composed of 5g DL-malic acid and 3g salicylic acid), 30g of film-forming agent (ice white rosin), 1g of surfactant (octylphenol polyoxyethylene ether-10), pH adjuster, 1g of antioxidant (hydroquinone), 1g of corrosion inhibitor (benzotriazole), and 5g of rheology modifier (hydrogenated castor oil) and continue to mix well to obtain the final product.

[0074] The photovoltaic module welding process in this embodiment includes the following steps:

[0075] S1: Install SnPbBi coated low-temperature interconnect strips on the welding machine;

[0076] S2: Apply photovoltaic module flux material evenly to the surface of the cell or interconnect strip using coating equipment, and use hot air for preliminary curing; the cell is one of HJT / Topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell.

[0077] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding, with a lamination temperature of 150℃ and a lamination time of 20min.

[0078] Example 2

[0079] The method for preparing the flux material for photovoltaic modules in this embodiment includes the following steps:

[0080] A: Add 100 mL of anhydrous ethanol, 0.05 mol of MAL-PEG-NH2 (PEG chain n is 800) and 0.11 mol of 2-aldehyde phenylboronic acid to a 500 mL four-necked flask equipped with a stirrer, thermometer, dropping funnel and condenser. After mixing well, add sodium borohydride and a small amount of PBS buffer solution. React at room temperature under nitrogen protection to obtain the precursor.

[0081] Then, in a round-bottom flask, 5g of the precursor and 0.77g of the furan derivative were dissolved in 150mL of anhydrous ethanol, a Lewis acid catalyst was added, and the mixture was refluxed for 5h to prepare the inhibitor.

[0082] B: Take 45g of solvent (composed of 5g ethylene glycol monobutyl ether, 10g propylene glycol methyl ether, 15g tetrahydrofurfuryl alcohol, and 15g n-octanol), 2g of inhibitor, mix well, then add 8g of activator (composed of 5g DL-malic acid and 3g salicylic acid), 30g of film-forming agent (ice white rosin), 1g of surfactant (octylphenol polyoxyethylene ether-10), pH adjuster, 1g of antioxidant (hydroquinone), 1g of corrosion inhibitor (benzotriazole), and 5g of rheology modifier (hydrogenated castor oil) and continue to mix well to obtain the final product.

[0083] The furan derivative of this embodiment was prepared by the following steps: 100 mL of tetrahydrofuran, 0.2 mol of triethylamine, and 0.3 mol of furfurylamine were added to a 500 mL three-necked flask and mixed thoroughly. The flask was then placed in an ice-water bath, and under nitrogen protection, 100 mL of tetrahydrofuran solution containing 0.1 mol of phenylphosphine dichloride was slowly added dropwise. After the addition was completed in 30 min, the mixture was reacted for 6 h. The mixture was then filtered, precipitated with petroleum ether, and the resulting precipitate was washed and dried to obtain the final product.

[0084] The photovoltaic module welding process in this embodiment includes the following steps:

[0085] S1: Install SnPbBi coated low-temperature interconnect strips on the welding machine;

[0086] S2: Apply photovoltaic module flux material evenly to the surface of the cell or interconnect strip using coating equipment, and use hot air for preliminary curing; the cell is one of HJT / Topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell.

[0087] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding, with a lamination temperature of 150℃ and a lamination time of 20min.

[0088] Control group 1

[0089] The preparation method of the flux material in this control group includes the following steps: Take 45g of solvent (composed of 5g ethylene glycol monobutyl ether, 10g propylene glycol methyl ether, 15g tetrahydrofurfuryl alcohol, and 15g n-octanol), 2g MAL-PEG-NH2 and mix them evenly. Then add 8g of activator (composed of 5g DL-malic acid and 3g salicylic acid), 30g of film-forming agent (ice white rosin), 1g of surfactant (octylphenol polyoxyethylene ether-10), pH adjuster, 1g of antioxidant (hydroquinone), 1g of corrosion inhibitor (benzotriazole), and 5g of rheology modifier (hydrogenated castor oil) and continue to mix evenly to obtain the final product.

[0090] The photovoltaic module welding process in this control group includes the following steps:

[0091] S1: Install SnPbBi coated low-temperature interconnect strips on the welding machine;

[0092] S2: Apply flux material evenly to the surface of the battery or interconnect strip using a coating device, and use hot air for initial curing; the battery is one of HJT / Topcon / BC battery, perovskite battery, or HJT\Topcon perovskite tandem battery.

[0093] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding, with a lamination temperature of 150℃ and a lamination time of 20min.

[0094] Control group 2

[0095] The preparation method of the flux material for photovoltaic modules in this control group includes the following steps:

[0096] A: Add 100 mL of tetrahydrofuran, 0.2 mol of triethylamine, and 0.3 mol of furfurylamine to a 500 mL three-necked flask and mix well. Then place the flask in an ice-water bath and slowly add 100 mL of tetrahydrofuran solution containing 0.1 mol of phenylphosphine dichloride under nitrogen protection. After the addition is completed in 30 min, react for 6 h. Filter the solution and precipitate with petroleum ether. Wash and dry the precipitate to obtain the furan derivative.

[0097] B: Take 45g of solvent (composed of 5g ethylene glycol monobutyl ether, 10g propylene glycol methyl ether, 15g tetrahydrofurfuryl alcohol, and 15g n-octanol), 2g of furan derivative, mix evenly, then add 8g of activator (composed of 5g DL-malic acid and 3g salicylic acid), 30g of film-forming agent (ice white rosin), 1g of surfactant (octylphenol polyoxyethylene ether-10), pH adjuster, 1g of antioxidant (hydroquinone), 1g of corrosion inhibitor (benzotriazole), and 5g of rheology modifier (hydrogenated castor oil) and continue to mix evenly to obtain the final product.

[0098] The photovoltaic module welding process in this control group includes the following steps:

[0099] S1: Install SnPbBi coated low-temperature interconnect strips on the welding machine;

[0100] S2: Apply flux material evenly to the surface of the battery or interconnect strip using a coating device, and use hot air for initial curing; the battery is one of HJT / Topcon / BC battery, perovskite battery, or HJT\Topcon perovskite tandem battery.

[0101] S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding, with a lamination temperature of 150℃ and a lamination time of 20min.

[0102] Performance testing

[0103] 1. Welding performance tests were conducted according to GB / T9491-2021 standard. Scanning electron microscopy was used to observe the cross-sectional morphology of the weld joints obtained with the flux materials in Examples 1-2 and Control Groups 1-2. The results are as follows: Figure 1 As shown, the flux material of this application effectively inhibits the growth of the IMC layer of the solder joint, refines the solder joint structure to a certain extent, and obtains a better welding effect.

[0104] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this invention.

Claims

1. A method for preparing a flux material for photovoltaic modules, characterized in that: Includes the following steps: A: A precursor is prepared by reacting MAL-PEG-NH2 and 2-aldehyde phenylboronic acid, and then the precursor is reacted with a furan derivative to prepare an inhibitor; the molar ratio of MAL-PEG-NH2 to 2-aldehyde phenylboronic acid is 1:(2-2.5); the mass ratio of the precursor to the furan derivative is (5-10):

1. B: Take 45g of solvent and 2g of inhibitor, mix them evenly, and then add 8g of activator, 30g of film-forming agent, 1g of surfactant, pH adjuster, 1g of antioxidant, 1g of corrosion inhibitor and 5g of rheology modifier and mix evenly to obtain the final product.

2. The method for preparing the flux material for photovoltaic modules according to claim 1, characterized in that: In step A, the n of the PEG chain in the MAL-PEG-NH2 molecule is less than 6000.

3. The method for preparing the flux material for photovoltaic modules according to claim 1, characterized in that: In step A, the furan derivative is prepared by reacting phenylphosphodichloro with furfurylamine.

4. The method for preparing the flux material for photovoltaic modules according to claim 1, characterized in that: In step B, the solvent is one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, tetrahydrofurfural, glycerol, diethylene glycol, and ethanol. And / or, in step B, the activator is one or more of the following: methylsuccinic acid, DL-malic acid, lactic acid, oxalic acid, sebacic acid, azelaic acid, citric acid, salicylic acid, palmitic acid, adipic acid, benzoic acid, and stearic acid; And / or, in step B, the film-forming agent is a rosin-based film-forming agent; And / or, in step B, the surfactant is a nonionic surfactant; And / or, in step B, the antioxidant is a phenolic antioxidant; And / or, in step B, the corrosion inhibitor is benzotriazole; And / or, in step B, the rheology modifier is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

5. A flux material for photovoltaic modules, characterized in that: It is prepared by any one of the preparation methods described in claims 1-4.

6. A serial welding composite lamination welding process, characterized in that: Includes the following steps: S1: Install interconnecting strips on the welding machine; S2: Apply photovoltaic module flux material evenly to the surface of the battery or interconnect strip using a coating device, and perform preliminary curing using hot air; the battery is one of HJT / TOPCon / BC battery, perovskite battery, or HJT / TOPCon perovskite tandem battery. The flux material for photovoltaic modules is prepared using the preparation method described in any one of claims 1-4; S3: After stacking the interconnecting strips and battery grid lines accordingly, pre-weld them together to form a string; then use lamination vacuum thermal welding to strengthen the welding.

7. The serial welding composite lamination welding process according to claim 6, characterized in that: In step S1, the interconnecting strip is a SnPb-coated interconnecting strip or a SnPbBi-coated low-temperature interconnecting strip.

8. The serial welding composite lamination welding process according to claim 6, characterized in that: In step S3, the pre-welding is performed using infrared, hot air, or electromagnetic welding.

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