Composite welding aid material, preparation method thereof and photovoltaic module lamination welding process

Abstract

The invention belongs to the technical field of photovoltaic welding, and particularly provides a composite welding aid material, a preparation method thereof and a photovoltaic module lamination welding process. Comprising the following steps: 1) uniformly mixing L-tartaric acid, fatty amine and xylene, then heating for reaction, filtering, and recrystallizing in deionized water to obtain a precursor; 2) dissolving sulfydryl-terminated polyethylene glycol and a cyclodextrin derivative in deionized water, then adding maleimide and a buffer solution, and reacting to obtain a regulating solution; 3, the precursor and the adjusting liquid are taken and mixed to be uniform, then the activating agent, the solvent, the film-forming agent, the surfactant, the pH adjusting agent, the antioxidant, the corrosion inhibitor and the rheological agent continue to be added and continue to be mixed to be uniform, and the composite welding-aid material is obtained.The composite welding-aid material has the advantages that the wettability of welding spots is improved, and the welding effect is improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic welding technology, and in particular relates to a composite flux material and a preparation method thereof, and a photovoltaic module lamination welding process. Background Art

[0002] With the continuous advancement and iteration of photovoltaic cell technology, several technical routes have been developed in cell welding technology. For example, in the topcon and HJT processes of OBB design, the glue spot welding process, film coating welding process, and XBC cell back welding process can currently be used.

[0003] Among them, the dispensing welding process has problems such as unstable welding quality, high process difficulty, and low yield; the film coating welding process has problems such as unstable film layer pull-off force, high difficulty in front-end EL quality control, and low production yield; the XBC battery back welding process has high welding accuracy, but the battery is easy to bend after welding, and the finished component fragmentation rate is high after lamination.

[0004] In this regard, in order to improve the welding quality of photovoltaic cells, technical personnel have carried out a series of research and development activities. For example, the patent document with application publication number CN112768544A discloses an IBC photovoltaic cell module and its welding process. By setting an insulating resin layer and a solder paste layer on the back of the cell, and connecting and connecting the solder paste layers in series with copper foil strips to replace the interconnection strips, costs are reduced. At the same time, the good mechanical properties and heat resistance of the insulating resin layer are utilized to reduce the occurrence of hidden cracks in the IBC cell, thereby improving the performance of the photovoltaic module.

[0005] For example, patent application publication number CN111112789A discloses a cell welding process for photovoltaic power generation cross-connected modules, including the following steps: Step 1: Determine the number of cells, check whether the cells have cracks or missing corners, confirm that the cells are intact, and then take a cell and place it face-up; Step 2: Pre-treat the interconnection strips; Step 3: Place a cell in the middle of the heating plate and lay a set of welding ribbons on the main grid lines of the cell; Step 4: Single-weld the cell; Step 5: Pre-treat before series welding; Step 6: Series weld the cells after single welding. This invention welds individual cells and then series welds multiple groups of cells. This method achieves good welding results, avoids welding offset or unstable contact that can occur with direct series welding, and improves welding quality. By soaking the interconnection strips in a properly formulated flux, wettability during welding can be improved.

[0006] The flux materials used in the above-mentioned welding process have limited improvement in the wettability of the solder joints during welding and cannot meet the performance requirements of high-performance photovoltaic modules. Therefore, how to improve the wettability during welding is a technical problem that needs to be solved urgently. Summary of the Invention

[0007] In response to the above problems, in order to further improve the wetting performance of solder joints during welding, the present application provides a composite flux material and a preparation method thereof, and a photovoltaic module lamination welding process.

[0008] This application first provides a method for preparing a composite flux material, comprising the following steps: 1) L-tartaric acid, fatty amine, and xylene are mixed evenly, then heated for reaction, filtered, and recrystallized in deionized water to obtain a precursor; 2) dissolving the thiol-terminated polyethylene glycol and the cyclodextrin derivative in deionized water, then adding maleimide and a buffer solution, and reacting to obtain a regulating solution; 3) Take the precursor and the regulating liquid and mix them evenly, then continue to add the activator, solvent, film-forming agent, surfactant, pH regulator, antioxidant, corrosion inhibitor, and rheological agent and continue to mix evenly.

[0009] Furthermore, in step 1), the molar ratio of L-tartaric acid to fatty amine is 1:(1-1.2).

[0010] Furthermore, in step 1), the heating reaction is carried out at a temperature of 110-135° C. for 1-3 hours.

[0011] Furthermore, in the step 2), the mass ratio of the thiol-terminated polyethylene glycol to the cyclodextrin derivative is (0.2-0.3):1.

[0012] Furthermore, in step 2), the cyclodextrin derivative is prepared by esterification and polycondensation of cyclodextrin and citric acid.

[0013] Furthermore, in step 3), the activator is one or more of 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 3), 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 3), the film-forming agent is a rosin-type film-forming agent; And / or, in step 3), the surfactant is a nonionic surfactant; And / or, in step 3), the antioxidant is a phenolic antioxidant; And / or, in step 3), the corrosion inhibitor is benzotriazole; And / or, in step 3), the rheological agent is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

[0014] The present application provides a composite flux material, which is prepared using the above-mentioned preparation method.

[0015] The present application also provides a photovoltaic module lamination welding process, comprising the following steps: S1: Install the interconnecting strip on the welding machine; S2: Use coating equipment to evenly apply composite flux material on the surface of the soldering pattern battery or interconnection bar, and use hot air for preliminary curing; and / or, using a coating device to evenly apply silver glue, solder paste, or composite flux material on the surface of the battery or the surface of the interconnect bar, and using hot air for preliminary curing; the battery is one of an HJT / topcon / BC battery, a perovskite battery, and an HJT / Topcon perovskite tandem battery; The composite flux material is prepared by the above-mentioned preparation method; S3: stack the interconnection bars and the battery grid lines accordingly and pre-weld them into strings.

[0016] Furthermore, in step S1, the interconnection bar is a SnPb-coated interconnection bar or a SnPbBi-coated low-temperature interconnection bar.

[0017] Compared with the prior art, this application has the following beneficial effects: 1. This application uses organic acid as an activator, and compounding precursor liquid, regulating liquid, film-forming agent, rheological agent and other additives can form a stable adsorption film on the metal surface, which plays a very good interface modification role during welding, so that the welding structure is refined, the wettability of the solder joint is improved, and the welding quality is improved.

[0018] 2. The precursor of the present application has a pyrrole ring and contains a hydroxyl group, which can form a stable adsorption on the metal surface. In addition, the cyclodextrin derivative in the conditioning solution can form a molecular sliding ring structure with the terminal thiol polyethylene glycol and construct a dynamic network cross-linking system under the end-capping effect of maleimide, thereby improving the interfacial adsorption state of the precursor and other components and reducing the IMC metal layer between the solder and the base metal during welding. Moreover, the precursor and conditioning solution can also form a trace carbon skeleton at high temperature as a physical barrier, inhibiting the diffusion of base metal atoms from the substrate side to the solder joint side, further inhibiting the growth rate of IMC, and also improving the wetting performance of the solder joint on the substrate, thereby obtaining a better welding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the solder joint wetting performance of Example 2 and Control Group 1 of the present application.

[0020] Figure 2 These are SEM images of the solder joint cross sections of Examples 1-2 and Control Groups 1-2 of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] After extensive experimental research, this application provides a method for preparing a composite flux material, comprising the following steps: 1) L-tartaric acid, fatty amine, and xylene are mixed evenly, then heated for reaction, filtered, and recrystallized in deionized water to obtain a precursor; 2) dissolving the thiol-terminated polyethylene glycol and the cyclodextrin derivative in deionized water, then adding maleimide and a buffer solution, and reacting to obtain a regulating solution; 3) Take the precursor and the regulating liquid and mix them evenly, then continue to add the activator, solvent, film-forming agent, surfactant, pH regulator, antioxidant, corrosion inhibitor, and rheological agent and continue to mix evenly.

[0023] Furthermore, in step 1), the molar ratio of L-tartaric acid to fatty amine is 1:(1-1.2).

[0024] In some specific embodiments, in step 1), the molar ratio of L-tartaric acid to fatty amine can be 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, or 1:2. More preferably, in step 1), a molar ratio of L-tartaric acid to fatty amine of 1:1.1 can achieve better experimental results.

[0025] In some specific embodiments, in step 1), the fatty amine can be one of propylamine, n-butylamine, dodecylamine, and octadecylamine. More preferably, in general, in step 1), when the fatty amine is n-butylamine, better technical effects can be achieved.

[0026] Furthermore, in step 1), the heating reaction is carried out at a temperature of 110-135° C. for 1-3 hours.

[0027] In some specific embodiments, in step 1), the heating reaction can be carried out at 110°C, 115°C, 120°C, 125°C, 130°C, or 135°C for 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours. More preferably, in general, better experimental results can be achieved when the heating reaction is carried out at 120°C for 2 hours in step 1).

[0028] Furthermore, in the step 2), the mass ratio of the thiol-terminated polyethylene glycol to the cyclodextrin derivative is (0.2-0.3):1.

[0029] In some specific embodiments, in step 2), the mass ratio of the thiol-terminated polyethylene glycol to the cyclodextrin derivative can be 0.2:1, 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1, 0.26:1, 0.27:1, 0.28:1, 0.29:1, or 0.3:1. More preferably, under normal circumstances, in step 2), a mass ratio of the thiol-terminated polyethylene glycol to the cyclodextrin derivative of 0.2:1 can achieve better results.

[0030] Furthermore, in step 2), the cyclodextrin derivative is prepared by esterification and polycondensation of cyclodextrin and citric acid.

[0031] Furthermore, in step 3), the activator is one or more of 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; In some specific embodiments, under normal circumstances, in step 3), when the organic acid consists of DL-malic acid and salicylic acid, better experimental results can be achieved. More preferably, in step 3), the organic acid consists of DL-malic acid and salicylic acid in a mass ratio of 5:3.

[0032] And / or, in step 3), the solvent is one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, tetrahydrofurfural, glycerol, diethylene glycol, and ethanol; In some specific embodiments, in step 3), the solvent selected from ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, and tetrahydrofurfural achieves better results. More preferably, under normal circumstances, the solvent is ethylene glycol monobutyl ether, propylene glycol methyl ether, n-octanol, and tetrahydrofurfural in a mass ratio of 1:2:3:3, which achieves better experimental results.

[0033] And / or, in step 3), the film-forming agent is a rosin-type film-forming agent; In some specific embodiments, more preferably, in step 1), the film-forming agent is ice white rosin.

[0034] And / or, in step 3), the surfactant is a nonionic surfactant; In some specific embodiments, more preferably, in step 1), when octylphenol polyoxyethylene ether is selected as the surfactant, the effect is better.

[0035] And / or, in step 3), the antioxidant is a phenolic antioxidant; In some specific embodiments, more preferably, in step 1), when hydroquinone is selected as the antioxidant, better experimental results can be obtained.

[0036] And / or, in step 3), the corrosion inhibitor is benzotriazole; And / or, in step 3), the rheological agent is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

[0037] The present application provides a composite flux material, which is prepared using the above-mentioned preparation method.

[0038] The present application also provides a photovoltaic module lamination welding process, comprising the following steps: S1: Install the interconnecting strip on the welding machine; S2: Use coating equipment to evenly apply composite flux material on the surface of the soldering pattern battery or interconnection bar, and use hot air for preliminary curing; and / or, using a coating device to evenly apply silver glue, solder paste, or composite flux material on the surface of the battery or the surface of the interconnect bar, and using hot air for preliminary curing; the battery is one of an HJT / topcon / BC battery, a perovskite battery, and an HJT / Topcon perovskite tandem battery; The composite flux material is prepared by the above-mentioned preparation method; S3: stack the interconnection bars and the battery grid lines accordingly and pre-weld them into strings.

[0039] Furthermore, in step S1, the interconnection bar is a SnPb-coated interconnection bar or a SnPbBi-coated low-temperature interconnection bar.

[0040] Generally, in step S1, better technical effects can be achieved when the interconnection bars are SnPbBi coated low-temperature interconnection bars.

[0041] Preferably, the photovoltaic module welding process of the present application can be applied to the welding of OBBtopcon / HJT cells and XBC / perovskite cells.

[0042] Example 1 The preparation method of the composite flux material of this embodiment includes the following steps: 1) Add 15 mL of xylene, 0.6 g of L-tartaric acid, and 0.322 g of n-butylamine to a 500 mL three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, mix well, and react at 120°C for 2 h under stirring. Then cool to room temperature and filter. The resulting product is recrystallized in deionized water to obtain a precursor. 2) Add 2 g of thiol-terminated polyethylene glycol and 10 g of sulfobutyl-β-cyclodextrin to a three-necked flask and dissolve them in deionized water. Then, add 0.5 g of maleimide and 10 mL of PBS buffer solution. After reaction, obtain a conditioning solution. 3) Take 0.35g of the precursor and 5mL of the regulating liquid and mix them evenly. Then, add 8g of the activator (composed of 5g of DL-malic acid and 3g of salicylic acid), 45g of the solvent (composed of 5g of ethylene glycol monobutyl ether, 10g of propylene glycol methyl ether, 15g of tetrahydrofurfuryl alcohol and 15g of n-octanol), 30g of the film-forming agent (ice white rosin), 1g of the surfactant (octylphenol polyoxyethylene ether-10), the pH regulator, 1g of the antioxidant (hydroquinone), 1g of the corrosion inhibitor (benzotriazole) and 5g of the rheological agent (hydrogenated castor oil) and continue to mix evenly.

[0043] The photovoltaic module welding process of this embodiment includes the following steps: S1: Install SnPbBi coated low temperature interconnect strips on the welding machine; S2: Use coating equipment to evenly apply composite flux material on the surface of the cell or interconnect bar, and use hot air for preliminary curing; the cell is one of HJT / topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell; S3: After stacking the interconnection strips and the battery grid lines correspondingly, they are laminated and connected into strings by vacuum heat welding. The lamination temperature is 150° C. and the lamination time is 20 minutes.

[0044] Example 2 The preparation method of the composite flux material of this embodiment includes the following steps: 1) Add 15 mL of xylene, 0.6 g of L-tartaric acid, and 0.322 g of n-butylamine to a 500 mL three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, mix well, and react at 120°C for 2 h under stirring. Then cool to room temperature and filter. The resulting product is recrystallized in deionized water to obtain a precursor. 2) Add 2 g of thiol-terminated polyethylene glycol and 10 g of a cyclodextrin derivative to a three-necked flask and dissolve them in deionized water. Then, add 0.5 g of maleimide and 10 mL of PBS buffer solution. After reaction, obtain a conditioning solution. 3) Take 0.35g of the precursor and 5mL of the regulating liquid and mix them evenly. Then, add 8g of the activator (composed of 5g of DL-malic acid and 3g of salicylic acid), 45g of the solvent (composed of 5g of ethylene glycol monobutyl ether, 10g of propylene glycol methyl ether, 15g of tetrahydrofurfuryl alcohol and 15g of n-octanol), 30g of the film-forming agent (ice white rosin), 1g of the surfactant (octylphenol polyoxyethylene ether-10), the pH regulator, 1g of the antioxidant (hydroquinone), 1g of the corrosion inhibitor (benzotriazole) and 5g of the rheological agent (hydrogenated castor oil) and continue to mix evenly.

[0045] The cyclodextrin derivative of this example was prepared by the following steps: 5 g of β-cyclodextrin, 2 g of citric acid, and 50 mL of deionized water were accurately weighed and added to a 250 mL round-bottom flask, mixed evenly, and then 1 g of potassium dihydrogen phosphate was added. After mixing evenly, the mixture was heated to 100° C. in an oil bath to completely dissolve the components to obtain a reaction solution. The reaction solution was then transferred to a hot air drying oven, stirred at 140° C. for 4 h, washed with deionized water, and dried.

[0046] The photovoltaic module welding process of this embodiment includes the following steps: S1: Install SnPbBi coated low temperature interconnect strips on the welding machine; S2: Use coating equipment to evenly apply composite flux material on the surface of the cell or interconnect bar, and use hot air for preliminary curing; the cell is one of HJT / topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell; S3: After stacking the interconnection strips and the battery grid lines correspondingly, they are laminated and connected into strings by vacuum heat welding. The lamination temperature is 160° C. and the lamination time is 16 minutes.

[0047] Control group 1 The preparation method of the soldering flux material of this control group includes the following steps: taking 8g of an activator (composed of 5g of DL-malic acid and 3g of salicylic acid), 45g of a solvent (composed of 5g of ethylene glycol monobutyl ether, 10g of propylene glycol methyl ether, 15g of tetrahydrofurfuryl alcohol, and 15g of n-octanol), 30g of a film-forming agent (ice white rosin), 1g of a surfactant (octylphenol polyoxyethylene ether-10), a pH regulator, 1g of an antioxidant (hydroquinone), 1g of a corrosion inhibitor (benzotriazole), and 5g of a rheological agent (hydrogenated castor oil), and mixing them evenly to obtain the soldering flux material.

[0048] The photovoltaic module welding process of this control group includes the following steps: S1: Install SnPbBi coated low temperature interconnect strips on the welding machine; S2: Use coating equipment to evenly apply flux material on the surface of the cell or interconnect bar, and use hot air for preliminary curing; the cell is one of HJT / topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell; S3: After stacking the interconnection strips and the battery grid lines correspondingly, they are laminated and connected into strings by vacuum heat welding. The lamination temperature is 150° C. and the lamination time is 20 minutes.

[0049] Control group 2 The preparation method of the composite flux material of the control group includes the following steps: 1) Add 15 mL of xylene, 0.6 g of L-tartaric acid, and 0.322 g of n-butylamine to a 500 mL three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, mix well, and react at 120°C for 2 h under stirring. Then cool to room temperature and filter. The resulting product is recrystallized in deionized water to obtain a precursor. 2) Take 0.35g of precursor, 8g of activator (composed of 5g of DL-malic acid and 3g of salicylic acid), 45g of solvent (composed of 5g of ethylene glycol monobutyl ether, 10g of propylene glycol methyl ether, 15g of tetrahydrofurfuryl alcohol and 15g of n-octanol), 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 rheological agent (hydrogenated castor oil) and continue to mix well.

[0050] The photovoltaic module welding process of this control group includes the following steps: S1: Install SnPbBi coated low temperature interconnect strips on the welding machine; S2: Use coating equipment to evenly apply flux material on the surface of the cell or interconnect bar, and use hot air for preliminary curing; the cell is one of HJT / topcon / BC cell, perovskite cell, or HJT\Topcon perovskite tandem cell; S3: After stacking the interconnection strips and the battery grid lines correspondingly, they are laminated and connected into strings by vacuum heat welding. The lamination temperature is 150° C. and the lamination time is 20 minutes.

[0051] Performance testing 1. Take the soldering materials of Example 2 and Control Group 1 and perform welding performance test according to GB / T9491-2021 standard. The results are as follows: Figure 1 It can be seen that the flux material of the present application can effectively improve the wetting performance of the solder joint.

[0052] 2. The cross-section morphology of the solder joints obtained from the soldering materials of Example 1-2 and Control Group 1-2 was observed using an electron scanning electron microscope. The results are as follows: Figure 2 As shown, it can be seen that the welding quality of the solder joint is effectively improved, and the interface defects and the thickness of the IMC layer are reduced.

[0053] Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a composite flux material, characterized in that: The steps include: 1) L-tartaric acid, fatty amine, and xylene are mixed evenly, then heated for reaction, filtered, and recrystallized in deionized water to obtain a precursor; 2) dissolving the thiol-terminated polyethylene glycol and the cyclodextrin derivative in deionized water, then adding maleimide and a buffer solution, and reacting to obtain a regulating solution; 3) Take the precursor and the regulating liquid and mix them evenly, then continue to add the activator, solvent, film-forming agent, surfactant, pH regulator, antioxidant, corrosion inhibitor, and rheological agent and continue to mix evenly.

2. The method for preparing the composite flux material according to claim 1, wherein: In the step 1), the molar ratio of L-tartaric acid to fatty amine is 1:(1-1.2).

3. The method for preparing the composite flux material according to claim 1, wherein: In the step 1), the heating reaction is carried out at a temperature of 110-135° C. for 1-3 hours.

4. The method for preparing the composite flux material according to claim 1, wherein: In the step 2), the mass ratio of the thiol-terminated polyethylene glycol to the cyclodextrin derivative is (0.2-0.3):

1.

5. The method for preparing the composite flux material according to claim 1, wherein: In the step 2), the cyclodextrin derivative is prepared by esterification and polycondensation of cyclodextrin and citric acid.

6. The method for preparing the composite flux material according to claim 1, wherein: In step 3), the activator is one or more of 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 3), 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 3), the film-forming agent is a rosin-type film-forming agent; And / or, in step 3), the surfactant is a nonionic surfactant; And / or, in step 3), the antioxidant is a phenolic antioxidant; And / or, in step 3), the corrosion inhibitor is benzotriazole; And / or, in step 3), the rheological agent is one or more of hydrogenated castor oil, ethyl cellulose, and polyamide wax.

7. A composite flux material, characterized in that: The method is as described in any one of claims 1 to 6.

8. A photovoltaic module lamination welding process, characterized by: The steps include: S1: Install the interconnecting strip on the welding machine; S2: Use coating equipment to evenly apply composite flux material on the surface of the soldering pattern battery or interconnection bar, and use hot air for preliminary curing; and / or, using a coating device to evenly apply silver glue, solder paste, or composite flux material on the surface of the battery or the surface of the interconnect bar, and using hot air for preliminary curing; the battery is one of an HJT / topcon / BC battery, a perovskite battery, and an HJT / Topcon perovskite tandem battery; The composite flux material is prepared by the preparation method according to any one of claims 1 to 6; S3: stack the interconnection strips and battery grid lines accordingly and connect them into strings by laminating and vacuum heat welding.

9. The photovoltaic module lamination welding process according to claim 8, characterized in that: In the step S1, the interconnection bar is a SnPb-coated interconnection bar or a SnPbBi-coated low-temperature interconnection bar.

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