Preparation method of photovoltaic welding strip, photovoltaic welding strip, photovoltaic module and preparation method

Abstract

The invention relates to a preparation method of a photovoltaic welding strip, the photovoltaic welding strip, a photovoltaic module and a preparation method, and the preparation method comprises the following steps: S1, carrying out the oxide removal and annealing treatment of an oxygen-free copper wire at the same time, and obtaining an annealed copper strip after cooling; s2, in the protection environment of inert gas, the annealed copper strip is immersed in molten brazing filler metal alloy liquid for surface tin plating, and after cooling, a plated copper strip with an alloy plating layer is obtained; s3, oxide on the surface of the plated copper strip is removed; s4, immersing the plated copper strip subjected to oxide removal into a film forming substance, and drying to obtain a film forming welding strip; wherein the film forming substance does not contain carboxyl. According to the method, oxide removal and annealing treatment are carried out at the same time, the photovoltaic welding strip which is high in preparation efficiency and can be welded without participation of scaling powder can be achieved, the photovoltaic welding strip is combined with the preparation technology of a photovoltaic module, and a high-reliability module can be obtained.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic new energy technology, and in particular to a method for preparing a photovoltaic welding ribbon, a photovoltaic welding ribbon, a photovoltaic module and a preparation method thereof. Background Art

[0002] Photovoltaic welding ribbon is an important material in the welding process of photovoltaic modules. It is also called tin-coated copper ribbon. It is divided into bus ribbon and interconnection ribbon according to its function and is used to connect the solar cells of photovoltaic modules. The welding quality of photovoltaic welding ribbon and solar module directly affects the collection efficiency of photovoltaic module electricity, and then affects the power generation of photovoltaic module.

[0003] In the current preparation process of photovoltaic solder strips, the relevant patent CN117888044A is consulted. This patent separates the annealing and deoxidation of the copper substrate. The production efficiency of the product needs to be improved, and the oxygen-free copper wire needs to be deoxidized by flux, and then immersed in molten solder liquid to complete tin plating. The main active ingredient of the commonly used flux is rosin, which is a carboxylic acid compound. It is inevitable to produce metal salt residues and activator residues, which poses a reliability risk; at the same time, the prepared photovoltaic solder strip still needs to apply flux on the surface tin layer during the subsequent welding process. The flux is an auxiliary material to ensure the smooth progress of the welding process. Its main function is to remove oxides on the surface of the solder strip and the substrate to be welded to achieve a certain degree of cleanliness. At the same time, it reduces the surface tension of the molten solder and improves the welding performance. However, metal salt residues and activator residues will still be produced, which also poses a reliability risk. Summary of the invention

[0004] Based on this, a preparation method of a photovoltaic welding strip, a photovoltaic welding strip, a photovoltaic module and a preparation method are provided, which can achieve high preparation efficiency and a photovoltaic welding strip that can be welded without the participation of flux. The photovoltaic welding strip is combined with the preparation process of the photovoltaic module to obtain a highly reliable module.

[0005] In a first aspect, the present application provides a method for preparing a photovoltaic ribbon, comprising the following steps:

[0006] S1: Deoxidizing and annealing the oxygen-free copper wire simultaneously, and obtaining an annealed copper strip after cooling;

[0007] S2: In an inert gas protective environment, the annealed copper strip is immersed in a molten solder alloy liquid for surface tinning, and after cooling, a coated copper strip with an alloy coating is obtained;

[0008] S3: remove oxides on the surface of the plated copper strip;

[0009] S4: immersing the plated copper strip after removing the oxide into a film-forming substance, and drying to obtain a film-forming welding strip; wherein the film-forming substance does not contain a carboxyl group.

[0010] A preferred solution is that in step S1, the method of deoxidation and annealing is: deoxidation and annealing are performed simultaneously in a high-temperature environment of nitrogen-hydrogen mixed gas or plasma containing hydrogen anions.

[0011] A preferred solution is that in step S3, the cleaning method is: treating the plated copper strip with a nitrogen-hydrogen mixed gas containing negative hydrogen ions or plasma cleaning or laser cleaning to remove oxides on the surface of the alloy coating.

[0012] In a second aspect, the present application provides a photovoltaic welding strip, using a method for preparing a photovoltaic welding strip as described above, wherein the photovoltaic welding strip comprises a copper strip, an alloy coating and a film-forming material from the inside to the outside.

[0013] A preferred solution is that the film-forming substance consists of a film-forming agent and a solvent, the volume proportion of the film-forming agent is ≤8%, and the rest is the solvent; wherein the melting point of the film-forming agent is greater than 220°C.

[0014] A preferred solution is that the film-forming agent is one or more of hydrocarbons, alcohols, and lipids.

[0015] A preferred solution is that the solvent is one or more of water, ethanol, and isopropanol.

[0016] In a third aspect, the present application provides a photovoltaic module, comprising a front panel material, a front adhesive film, a battery string, a back adhesive film, and a back panel material stacked in sequence; wherein the battery string comprises battery cells, adhesive components or fixing components, and the photovoltaic welding strip as described above.

[0017] In a fourth aspect, the present application provides a method for preparing a photovoltaic module according to the present invention, comprising the following steps:

[0018] S1: applying adhesive components on the front and back of the battery cell respectively;

[0019] S2: pre-fixing the photovoltaic welding ribbons to the bonding components on the front and back of the battery cells respectively, and repeating this step to complete the stacking of the battery strings;

[0020] S3: curing the adhesive components on the front and back of the cell, fixing the photovoltaic ribbon on the cell, and completing the production of the cell string;

[0021] S4: Arrange, stack, and laminate several battery strings according to a layout, so that the photovoltaic welding ribbon forms an alloy contact with the fine grid of the battery cell during the lamination process, and finally obtain a photovoltaic module.

[0022] In a fifth aspect, the present application provides a method for preparing a photovoltaic module according to the present invention, comprising the following steps:

[0023] S1: pre-fix the fixing components and the photovoltaic welding ribbon on the front and back of the battery sheet, and repeat this step to complete the stacking of the battery string;

[0024] S2: The stacked battery string is heated, and the fixing member above the photovoltaic welding ribbon shrinks due to the heat. After cooling, the photovoltaic welding ribbon is fixed on the battery sheet to complete the production of the battery string;

[0025] S3: Arrange several battery strings according to the layout, stack and laminate them. During the lamination process, the photovoltaic welding ribbon forms an alloy contact with the fine grid of the battery cell to finally obtain a photovoltaic module.

[0026] Beneficial effects:

[0027] First, the preparation method of the photovoltaic welding strip of the present application combines the deoxidation of the copper strip with the annealing step. Compared with the traditional method of first annealing in an inert gas environment and then applying flux on the surface to remove the oxide, the preparation method of the present application performs the deoxidation and annealing of the copper strip simultaneously, which improves the preparation efficiency of the photovoltaic welding strip and removes the flux in the photovoltaic welding strip production process; at the same time, the oxide on the surface of the photovoltaic welding strip is also removed in the preparation method, and a film-forming substance is applied to the surface of the photovoltaic welding strip after the oxide is removed. During the welding process, the film-forming substance does not participate in the reaction, and the melting point of the film-forming agent in the film-forming substance is relatively high. At 220°C, it will not volatilize during the welding process, and then it can effectively isolate oxygen, prevent the oxidation of the photovoltaic welding strip during the welding process, and then no oxides will be produced during the welding process; and because the film-forming substance does not contain carboxyl groups, it will not react with oxides during the welding process. Moreover, no oxides are produced in this application, and then no carboxylates will be produced, and no harm will be caused; in addition, the film-forming substance can reduce the surface tension, which helps the photovoltaic welding strip and the silver paste on the battery cell to form an alloy, thereby forming a good welding effect. Therefore, the use of the film-forming substance of this application not only has the effect of reducing the surface tension of traditional flux, but also can prevent the production of carboxylates. Compared with the traditional method of applying flux again to the welding strip during the welding process of photovoltaic components, relying on the active substances in the flux to remove oxides to ensure the smooth welding of the welding strip and the silver-plated layer of the battery, the preparation method of the component of this application no longer needs to rely on the active substances in the flux to remove oxides, and completely eliminates the hidden dangers caused by the residual active agent and the residual metal salts.

[0028] Secondly, the photovoltaic modules made by using the photovoltaic welding ribbon of the present application have higher reliability than the photovoltaic modules made by using the traditional welding ribbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of oxygen-free copper wire in Example 1 of the present application sequentially passing through a heat treatment device and a dipping tank;

[0030] Figure 2 This is a schematic diagram of the equipment composition in the method for preparing a photovoltaic welding ribbon in Example 1 of the present application;

[0031] Figure 3 This is an internal schematic diagram of the deoxidation device in Example 1 of the present application;

[0032] Figure 4 This is a cross-sectional schematic diagram of the photovoltaic welding ribbon in the second embodiment of the present application;

[0033] Figure 5 This is a schematic diagram of a photovoltaic module in Example 3 of the present application;

[0034] Figure 6 This is a schematic diagram of a photovoltaic welding ribbon being fixed to a solar cell by an adhesive component in the fourth embodiment of the present application;

[0035] Figure 7 This is a schematic diagram of the photovoltaic welding strip in Example 5 of the present application being fixed to the battery cell through a fixing component.

[0036] Figure numerals: 1. oxygen-free copper wire; 2. heat treatment equipment; 3. immersion plating tank; 4. coated copper strip; 5. deoxidation equipment; 51. furnace; 52. electron emission device; 53. conveying device; 6. film-forming equipment; 7. photovoltaic welding strip; 7-1. copper strip; 7-2. alloy coating; 7-3. film-forming material layer; 8. cutting mechanism; 9. traction equipment; 10. photovoltaic module; 11. battery cell; 12. bonding component; 13. fixing component. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner, and therefore the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0039] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0040] The directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "middle", "longitudinal", "lateral", "horizontal", "inner", "outer", "radial", "circumferential" and the like in this specification are based on the directions or positional relationships shown in the drawings and are only for the convenience of simplifying the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0041] At present, in the preparation process of photovoltaic welding strips, the annealing and deoxidation of the copper substrate are carried out separately, and the production efficiency of the product needs to be improved. In addition, deoxidation is achieved by flux. The main active ingredient of the commonly used flux is rosin, which is a carboxylic acid compound, and it is inevitable to produce metal salt residues and activator residues. At the same time, when using this type of photovoltaic welding strip in the welding process of photovoltaic modules, it is still necessary to apply flux on the surface tin layer to ensure smooth welding of the welding strip and the silver-plated layer of the battery. This practice will also produce metal salt residues and activator residues. The metal salt residue is hygroscopic, expands in volume in a humid environment, and causes corrosion. At the same time, if the activator in the flux is not completely decomposed, it will remain on the surface of the battery and corrode the welding strip and the battery, posing a reliability risk. For busbar-free modules, the melting point of the welding strip is lower, and the welding step is undertaken by lamination. The flux is wrapped by the film material and cannot evaporate into the air. If the traditional flux coating solution is used, the module has a great risk of failure.

[0042] The embodiments of the present application provide a method for preparing a photovoltaic welding strip, a photovoltaic welding strip, a photovoltaic module and a preparation method, in which deoxidation and annealing of the copper strip are performed simultaneously, thereby improving the preparation efficiency of the photovoltaic welding strip and removing the flux of the photovoltaic welding strip during the production process; at the same time, a film-forming substance is applied to the surface of the photovoltaic welding strip after the oxide is removed, and the film-forming substance does not contain a carboxyl group, and the melting point of the film-forming agent is relatively high, greater than 220°C, and it will not volatilize when heated during the welding process, and can then effectively isolate oxygen during high-temperature welding to prevent oxidation of the photovoltaic welding strip during the welding process. No oxides are generated during the welding process, and there is no need to rely on the active substances in the flux to remove the oxides, thereby completely eliminating the hidden dangers caused by the residual active agent and the residual metal salt; and the photovoltaic module prepared using such a photovoltaic welding strip has higher reliability than the photovoltaic module prepared using the traditional photovoltaic welding strip.

[0043] Example 1

[0044] The following is a detailed description of a method for preparing a photovoltaic welding ribbon provided in this embodiment in conjunction with the accompanying drawings. Figure 1 As shown, the following steps are included:

[0045] Step S1: Deoxidizing and annealing the oxygen-free copper wire simultaneously, and obtaining an annealed copper strip after cooling;

[0046] In this embodiment, it should be noted that the oxygen-free copper wire 1 is the raw material for preparing the photovoltaic welding strip. The oxygen-free copper wire reel is installed, the copper wire is threaded, the wire is paid out through a pay-off rack, and the paid-out oxygen-free copper wire 1 is pulled to each process in sequence through a traction mechanism. In this process, the oxygen-free copper wire 1 is first introduced into a nitrogen-hydrogen mixed gas containing hydrogen anions (the volume of hydrogen in the nitrogen-hydrogen mixed gas is less than 4%) or a high-temperature environment of plasma such as 600°C for deoxidation and annealing treatment at the same time, and then cooled to obtain the annealed copper strip. Specifically, the oxygen-free copper wire 1 can be introduced into the interior of the heat treatment equipment 2, and a nitrogen-hydrogen mixed gas containing hydrogen anions (the volume of hydrogen in the nitrogen-hydrogen mixed gas is less than 4%) or argon plasma is diffused in the interior of the heat treatment equipment 2. The oxygen-free copper wire 1 can be deoxidized and annealed at the same time in the interior of the heat treatment equipment 2. The surface oxide of the oxygen-free copper wire 1 can be reduced by hydrogen anions or argon plasma, and then the oxide can be removed by reducing the oxide. Nitrogen is used as a protective gas to achieve an explosion-proof effect; the copper wire is softened and stress is removed by short-circuit annealing, so that the copper wire improves its yield strength and tensile strength. Cooling after annealing is to facilitate the subsequent immersion plating procedure. The pay-off frame and traction mechanism in this step are existing equipment. The pay-off frame is used for the installation and pay-off of the pay-off drum, and the traction mechanism is used to pull the copper wire.

[0047] Please continue to refer to Figure 1 As shown, step S2: in an inert gas protective environment, immersing the annealed copper strip into a molten solder alloy liquid for surface tinning, and obtaining a coated copper strip with an alloy coating after cooling.

[0048] In this embodiment, it should be noted that in an inert gas protection environment, the annealed copper strip is immersed in a molten solder alloy liquid for high-speed tin plating on the surface, and after cooling, a coated copper strip 4 with an alloy coating is obtained, and the alloy coating is a low-temperature alloy, and the melting point of the low-temperature alloy is 130-148°C. Specifically, the annealed copper strip is introduced into a dip-plating tank 3 for high-speed surface dip-plating, and then the production of the coated copper strip is completed after natural cooling, that is, a coated copper strip 4 with an alloy coating is obtained, wherein the dip-plating tank 3 contains a molten solder alloy liquid, and in this embodiment, Sn is selected. 32 Pb 42 Bi 26 In addition, since the oxygen-free copper wire 1 is deoxidized in the previous stage and the surface is tinned in the protective environment of inert gas in this step, no oxide is formed between the oxygen-free copper wire 1 and the alloy plating layer.

[0049] Please refer to Figure 1 , Figure 2 As shown, step S3: removing oxides on the surface of the alloy coating;

[0050] In this embodiment, it should be noted that after the tin plating in step S2, the coated copper strip 4 is treated with a nitrogen-hydrogen mixed gas containing negative hydrogen ions or plasma cleaning or laser cleaning to remove the oxide on the surface of the alloy coating. Specifically, the coated copper strip 4 can be introduced into the interior of the deoxidation device 5, and a nitrogen-hydrogen mixed gas containing negative hydrogen ions (the volume of hydrogen in the nitrogen-hydrogen mixed gas is less than 4%) or argon plasma is diffused in the interior of the deoxidation device 5, and the coated copper strip 4 can remove the surface oxide in the interior of the deoxidation device 5, and the temperature of the deoxidation device 5 is set at 120°C.

[0051] It should be noted that the deoxidation equipment 5 utilizes the electron attachment (EA) principle to activate the hydrogen in the non-flammable nitrogen-hydrogen (<4% hydrogen) mixture, thereby achieving the purpose of removing oxides: when low-energy electrons collide with hydrogen molecules, the hydrogen molecules produce excited molecular hydrogen ions, which then dissociate to obtain atomic hydrogen ions. The atomic hydrogen ions will automatically move to the welding surface for reduction reaction under the drive of the applied electric field.

[0052] H2+e-→h2-*→H-+H (1)

[0053] H+e-→H-* (2)

[0054] 2H-+SnO→Sn+H2O+2e- (3)

[0055] Reaction (1) describes the dissociative attachment of hydrogen molecules, where a hydrogen molecule (H 2 ) combines with electrons (e-) to produce excited molecular hydrogen ions (H 2-* ), and then dissociated to obtain atomic hydrogen ions (H - ) and neutral hydrogen atoms (H). The neutral hydrogen atom can capture an electron again by direct attachment (2) to form an excited atomic hydrogen anion (H-*). The excited atomic anion can be stabilized by releasing photons or colliding with nitrogen molecules. Nitrogen is inert to EA as a diluent gas because its electron affinity is close to zero. Driven by the applied electric field, the atomic hydrogen anions formed under EA will automatically move to the welding surface for reduction reaction. Reaction (3) gives an example of the reduction of tin monoxide. The water vapor generated in the reaction can be discharged out of the furnace along the airflow, and the free electrons can be removed in an appropriate manner.

[0056] Please refer to Figure 2 , Figure 3As shown, specifically, the deoxidation equipment 5 is provided with a furnace 51, an electron emission device 52 containing a large number of needles is installed on the top of the furnace 51, and a non-flammable nitrogen-hydrogen mixed gas (<4% hydrogen) is introduced into the furnace 51. The electronic components to be welded, such as the coated copper strip 4, are loaded on the conveying device 53 of the furnace 51 and are continuously transported from the inlet end to the outlet end of the furnace 51. When the coated copper strip 1 passes under the electron emission device 52, it will be completely in the EA-activated atmosphere. After completing the surface cleaning under the EA, the coated copper strip 1 is sent out for normal operations such as welding and cooling.

[0057] Please continue to refer to Figure 1 , Figure 2 As shown, step S4: immersing the plated copper strip after removing the oxide into a film-forming substance, and obtaining a photovoltaic welding strip with a film after drying; wherein the film-forming substance does not contain a carboxyl group.

[0058] In this embodiment, it should be noted that the coated copper strip 4 after the oxide is removed is immersed in a film-forming substance, and a film-forming welding strip is obtained after drying, wherein the film-forming substance used for film formation does not contain carboxylic acid substances such as rosin, that is, it does not contain a carboxyl group. Specifically, the film-forming substance is composed of a film-forming agent and a solvent, the volume proportion of the film-forming agent is ≤8%, the melting point is relatively high and is greater than 220°C, and the film-forming agent is one of hydrocarbons, alcohols, and lipids, preferably polyethylene glycol; the rest is a solvent, and the solvent is one of water, ethanol, and isopropanol, preferably water. Specifically, the coated copper strip 4 is pulled into the film-forming device 6 containing the film-forming substance by the pulling device 9, and the surface of the coated copper strip 4 passing through the film-forming device 6 will be evenly coated with a layer of film-forming substance, which is dried so that the film-forming substance is effectively wrapped on the surface of the coated copper strip 4, and then a photovoltaic welding strip 7 with a film is obtained. After the oxygen-free copper wire 1 passes through the above processing steps, a film-forming welding strip is made, and finally it is cut by the cutting mechanism 8 at the rear end, and finally it is rolled onto a plastic reel using a winder, and the welding strip is prepared. It should be noted that the winder is an existing device, which is used for winding the finished welding strip, the cutting mechanism 8 is an existing device, which is used for cutting the film-forming welding strip, and the traction device 9 is an existing device, which is used for traction of the coated copper strip 4. Of course, the film-forming device 6 in this embodiment can be a tank soaked with a film-forming substance, and the coated copper strip 4 can be evenly coated by the film-forming substance when it is introduced into the tank. As for how to set it, there is no specific restriction in this embodiment.

[0059] In the preparation method of the photovoltaic welding strip of the embodiment of the present application, the oxygen-free copper wire 1 is simultaneously deoxidized and annealed in a high-temperature environment of a nitrogen-hydrogen mixed gas or plasma containing negative hydrogen ions, and then the surface is dip-plated to obtain a coated copper strip 4. The oxide on the surface of the oxygen-free copper wire 1 is removed by utilizing the reducing effect of negative hydrogen ions or plasma. Compared with the traditional method of first annealing in an inert gas environment and then applying a flux on the surface to remove the oxide, this step improves the preparation efficiency of the photovoltaic welding strip by simultaneously deoxidizing and annealing, and also omits the use of flux, avoiding the generation of metal salt residues and activator residues at the front end; when the coated copper strip 4 is used to connect the battery cell, the oxide on the surface is again removed by the negative hydrogen ions. Or it can be removed by plasma cleaning or laser cleaning, and it is only necessary to apply a film-forming substance on the surface of the plated copper strip 4 after the oxide is removed. The film-forming substance does not contain a carboxyl group, and the melting point of the film-forming agent is relatively high, greater than 220°C. During the welding process, the film-forming agent does not participate in the reaction and will not volatilize when heated, thereby effectively isolating the oxygen during high-temperature welding to prevent the photovoltaic welding strip from oxidizing during the welding process, and then no oxide is generated during the welding process; furthermore, the film-forming substance does not contain a carboxyl group, and will not react with the oxide during the welding process, and then no carboxylate substances will be generated, and no harm will be caused. There is no need to rely on the active substances in the flux to remove the oxides generated by heating during the component welding process like traditional welding strips, and the hidden dangers caused by the residual active agent and the residual metal salt are completely eliminated.

[0060] Example 2

[0061] Please refer to Figure 4 As shown, a photovoltaic welding strip is also provided in this embodiment, which uses a method for preparing a photovoltaic welding strip as described above, wherein the photovoltaic welding strip 7 includes a copper strip 7-1, an alloy coating 7-2 and a film-forming material layer 7-3 from the inside to the outside.

[0062] In some embodiments, the alloy plating layer 7 - 2 includes but is not limited to a tin-based alloy solder.

[0063] The film-forming material layer 7-3 is composed of a film-forming agent and a solvent, wherein the volume proportion of the film-forming agent is ≤8%, and the rest is the solvent. The film-forming agent is one or more of hydrocarbons, alcohols, and lipids, preferably polyethylene glycol; the solvent is one or more of water, ethanol, and isopropanol, preferably water.

[0064] Example 3

[0065] Please refer to Figure 5 As shown, a photovoltaic module is also provided in this embodiment, and the photovoltaic module 10 includes a front panel material, a front adhesive film, a battery string, a back adhesive film, and a back panel material stacked in sequence; wherein the battery string includes battery cells, adhesive components or fixing components and the above-mentioned photovoltaic welding strip 7.

[0066] Example 4

[0067] Please refer to Figure 6 As shown, this embodiment also provides a method for preparing a photovoltaic module, comprising the following steps:

[0068] Step S1: applying adhesive components on the front and back of the battery cell respectively;

[0069] In this embodiment, it should be noted that the battery cell 11 uses a busbar-free heterojunction battery, and an adhesive component 12 is applied to the front and back of the battery cell 11. The adhesive component can be a light-curing adhesive or a thermosetting adhesive. In an achievable manner, glue is applied to the battery cell 11 so that a plurality of glue points arranged in sequence and at intervals are formed on each installation position of the photovoltaic welding strip 7 of the battery cell 11.

[0070] Step S2: pre-fixing the photovoltaic welding ribbons to the adhesive components on the front and back sides of the battery cells respectively, and repeating this step to complete the stacking of the battery strings;

[0071] In this embodiment, it should be noted that the photovoltaic welding ribbon 7 is placed on the battery cell 11 in a direction perpendicular to the fine grid on the battery cell 11 for preliminary positioning, one end of the photovoltaic welding ribbon 7 falls above the battery cell 11, and the other end falls below the adjacent battery cell 11, connecting the positive and negative poles of the two adjacent cells to achieve circuit connection. After preliminary positioning, a press is used to fix the photovoltaic welding ribbon 7 to the adhesive components 12, i.e., glue points, on the front and back sides of the battery cell 11, respectively, and this step is repeated to complete the stacking of the battery string.

[0072] Step S3: curing the adhesive components on the front and back of the cell, fixing the photovoltaic welding ribbon on the cell, and completing the production of the cell string;

[0073] In this embodiment, it should be noted that the adhesive component 12 such as photocuring glue is rapidly solidified by using UV lamp irradiation. The photocuring glue contains UV glue components, which can be rapidly cured within a few seconds to more than ten seconds by UV lamp irradiation, and then the photovoltaic welding strip 7 is fixed on the battery cell 11; or, the adhesive component 12 such as thermosetting glue is cured by heating, and then the photovoltaic welding strip 7 is fixed on the battery cell 11, thereby completing the production of the battery string. The use of the adhesive component 12 can improve the bonding tightness between the photovoltaic welding strip 7 and the battery cell 11 on the one hand, and prevent the welding strip from falling off due to vibration, affecting the use of the battery cell 11; on the other hand, it can protect the photovoltaic welding strip 7 when external impact occurs.

[0074] Step S4: Arrange, stack, and laminate several battery strings according to the layout. During the lamination process, the photovoltaic welding ribbon forms a good alloy contact with the fine grid of the battery cell, and finally a photovoltaic module is obtained.

[0075] In this embodiment, it should be noted that the above-mentioned battery string is arranged, stacked and laminated according to the stacking drawing, so that the photovoltaic welding ribbon 7 forms a good alloy contact with the fine grid of the battery cell 11 during the lamination process, and finally a photovoltaic module is obtained.

[0076] Example 5

[0077] Please refer to Figure 7 As shown, this embodiment also provides a method for preparing a photovoltaic module, comprising the following steps:

[0078] S1: pre-fix the fixing components and the photovoltaic welding ribbon on the front and back of the battery sheet, and repeat this step to complete the stacking of the battery string;

[0079] In this embodiment, it should be noted that the fixing component 13 can be a film material such as pure PO material (propylene oxide) or EVA material (ethylene-vinyl acetate copolymer and rubber-plastic foam material made thereof), and the film material is laid on the photovoltaic welding ribbon 7 and the main grid-free battery cell 11. After heating, the film material will produce a cross-linking reaction and have a certain adhesive property to fix the photovoltaic welding ribbon 7 on the main grid-free battery cell 11.

[0080] First, place the photovoltaic welding ribbon 7 on the battery cell 11 in a direction perpendicular to the fine grid on the battery cell 11 for preliminary positioning, with one end of the photovoltaic welding ribbon 7 falling above the battery cell 11 and the other end falling below the adjacent battery cell 11. Then, lay the film material on the photovoltaic welding ribbon 7 in the direction of the fine grid. The film material covers the arranged photovoltaic welding ribbons 7, and the film material and the photovoltaic welding ribbon 7 are pressed on the front and back of the battery cell 11 by a press. Repeat this step to complete the stacking of the battery string.

[0081] S2: The stacked battery string is heated, and the film material above the photovoltaic welding ribbon shrinks due to the heat. After cooling, the photovoltaic welding ribbon is fixed on the battery sheet to complete the production of the battery string;

[0082] In this embodiment, it should be noted that the stacked battery string is subjected to a heating treatment, and the film material above the photovoltaic welding ribbon 7 will shrink due to the heat. After cooling, the photovoltaic welding ribbon 7 is fixed on the battery cell 11 to complete the production of the battery string. Specifically, the battery string is passed through an infrared light box, which heats the film material, and the film material above the photovoltaic welding ribbon 7 shrinks due to the heat. After cooling, the photovoltaic welding ribbon 7 is fixed, and then the production of the battery string is completed.

[0083] S3: Arrange several battery strings according to the layout, stack and laminate them. During the lamination process, the photovoltaic welding ribbon forms a good alloy contact with the fine grid of the battery cell, and finally a photovoltaic module is obtained.

[0084] In this embodiment, it should be noted that the above-mentioned battery string is arranged, stacked and laminated according to the stacking drawing, so that the photovoltaic welding ribbon 7 forms a good alloy contact with the fine grid of the battery cell during the lamination process, and finally a photovoltaic module is obtained.

[0085] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing a photovoltaic welding ribbon, characterized in that: The steps include: S1: Deoxidizing and annealing the oxygen-free copper wire simultaneously, and obtaining an annealed copper strip after cooling; S2: In an inert gas protective environment, the annealed copper strip is immersed in a molten solder alloy liquid for surface tinning, and after cooling, a coated copper strip with an alloy coating is obtained; S3: remove oxides on the surface of the plated copper strip; S4: immersing the plated copper strip after removing the oxide into a film-forming substance, and drying to obtain a film-forming welding strip; wherein the film-forming substance does not contain a carboxyl group.

2. The method for preparing a photovoltaic welding ribbon according to claim 1, characterized in that: In the step S1, the method of the deoxidation and annealing treatment is: deoxidation and annealing are performed simultaneously in a high temperature environment of nitrogen-hydrogen mixed gas or plasma containing hydrogen anions.

3. The method for preparing a photovoltaic ribbon according to claim 1, characterized in that: In step S3, the cleaning method is: treating the plated copper strip with a nitrogen-hydrogen mixed gas containing negative hydrogen ions or plasma cleaning or laser cleaning to remove oxides on the surface of the alloy coating.

4. A photovoltaic welding ribbon, characterized in that: A method for preparing a photovoltaic welding strip as described in any one of claims 1 to 3 above, wherein the photovoltaic welding strip comprises a copper strip, an alloy coating and a film-forming material from the inside to the outside.

5. The photovoltaic welding strip according to claim 4, characterized in that: The film-forming substance consists of a film-forming agent and a solvent, wherein the volume proportion of the film-forming agent is ≤8% and the rest is the solvent; wherein the melting point of the film-forming agent is greater than 220°C.

6. The photovoltaic welding strip according to claim 5, characterized in that: The film-forming agent is one or more of hydrocarbons, alcohols and lipids.

7. The photovoltaic welding ribbon according to claim 5, characterized in that: The solvent is one or more of water, ethanol and isopropanol.

8. A photovoltaic module, characterized in that: It includes a front plate material, a front adhesive film, a battery string, a back adhesive film, and a back plate material which are stacked in sequence; Wherein, the battery string comprises a battery cell, an adhesive component or a fixing component and a photovoltaic welding strip as described in any one of claims 4-7.

9. A method for preparing a photovoltaic module according to claim 8, characterized in that: The steps include: S1: applying adhesive components on the front and back of the battery cell respectively; S2: pre-fixing the photovoltaic welding ribbons to the bonding components on the front and back of the battery cells respectively, and repeating this step to complete the stacking of the battery strings; S3: curing the adhesive components on the front and back of the cell, fixing the photovoltaic ribbon on the cell, and completing the production of the cell string; S4: Arrange, stack, and laminate several battery strings according to a layout, so that the photovoltaic welding ribbon forms an alloy contact with the fine grid of the battery cell during the lamination process, and finally obtain a photovoltaic module.

10. A method for preparing a photovoltaic module according to claim 8, characterized in that: The steps include: S1: pre-fix the fixing components and the photovoltaic welding ribbon on the front and back of the battery sheet, and repeat this step to complete the stacking of the battery string; S2: The stacked battery string is heated, and the fixing member above the photovoltaic welding ribbon shrinks due to the heat. After cooling, the photovoltaic welding ribbon is fixed on the battery sheet to complete the production of the battery string; S3: Arrange several battery strings according to the layout, stack and laminate them. During the lamination process, the photovoltaic welding ribbon forms an alloy contact with the fine grid of the battery cell to finally obtain a photovoltaic module.

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