Photovoltaic module connecting solder strip and fixing method thereof

Abstract

The invention provides a photovoltaic module connecting solder strip and a fixing method thereof. The cross section of the photovoltaic module connecting solder strip comprises a protruding structure, and is rectangular or oblate; the number of the protruding structures is N, and N ranges from 3 to 100. The distance difference between the concave part of the protruding structure and the highest point of the protruding structure and the center of the cross section of the welding strip is 0.1-400 [mu] m; the distance between the highest points of two adjacent bulges is 0.1-400 microns; and the height-width ratio of the rectangle or the oblate shape is 0.05-0.3. According to the fixing method of the photovoltaic module connecting solder strip, the conductive ink is printed on the battery piece, and then the photovoltaic module connecting solder strip is pressed on the conductive ink, so that firm connection between the photovoltaic module connecting solder strip and the battery piece is realized; the fixing method provided by the invention is simple to operate, reduces the use amount of the silver paste, and further reduces the preparation cost of the photovoltaic module.

Description

[0001] This application claims the priority of patent application No. 2024101441166 (the filing date of the prior application is February 1, 2024, and the name of the invention is A photovoltaic module connecting welding ribbon and its fixing method) and the priority of patent application No. 2024101744614 (the filing date of the prior application is February 7, 2024, and the name of the invention is A photovoltaic module connecting welding ribbon and its fixing method). Technical Field

[0002] The present invention relates to the technical field of photovoltaic modules, and in particular to a photovoltaic module connecting welding strip and a fixing method thereof. Background Art

[0003] The cells of photovoltaic modules are getting thinner and thinner. The stress during hot welding and string welding will lead to a high rate of cell fragmentation. With the continuous development of battery technology, low-temperature processes are needed, and silver paste needs to be saved. Researchers have developed 0BB technology, which achieves the purpose of saving silver paste without a main grid by melting the welding ribbon at a low temperature of 139°C or using a carrier film or using a dispensing film with an integrated film or using a dispensing film + electric welding with an integrated film or using a skin film with a low-temperature welding ribbon + an ordinary packaging film. However, these technical solutions still have the defect that the welding ribbon itself has no pulling force with the battery, and the conductive glue is not used because of its high cost, and it is also necessary to produce a complex integrated film at a high price.

[0004] CN113178503A discloses a photovoltaic cell, a method for fixing a welding strip, a finished assembly and a method for preparing the same. The method for fixing a welding strip of a photovoltaic cell comprises: setting a first glue line with a length of 0.1 mm to 220 mm on the surface of the photovoltaic cell, bonding the welding strip to the surface of the photovoltaic cell through the first glue line, cross-arranging the welding strip and the first glue line, and overlapping the welding strip with at least part of the grid line to solidify the first glue line. The welding strip is fixed to the surface of the photovoltaic cell through the first glue line. Since the first glue line has a certain length, compared with point fixation, the laying accuracy window of the welding strip is relatively larger, and the risk of connection failure between the welding strip and the photovoltaic cell is lower.

[0005] CN115846928A discloses a welding strip, a photovoltaic module and a battery welding method. The welding strip includes a core and an alloy coating disposed on the surface of the core. The chemical composition of the alloy coating includes Sn, Nb, C and inevitable impurities; or, the chemical composition of the alloy coating includes Sn, Pb, Nb, C and inevitable impurities. During welding, when the alloy is transformed from liquid to solid, Nb and C form NbC particles. During the growth process after the matrix grains form crystal nuclei during the alloy cooling process, the in-situ generated NbC particles have a pinning effect on the grain boundaries, hindering the further growth of the matrix grains, achieving fine grain strengthening of the matrix grains, improving the mechanical properties of the welding position, and meeting the welding quality of the welding strip and the battery grid line under the conditions of laser low-temperature welding. The photovoltaic module uses the welding strip to weld the battery sheet, and the battery welding method uses the welding strip for laser low-temperature welding.

[0006] CN103413861A discloses a photovoltaic module reflective film and a method for fixing the film to a welding strip. The photovoltaic module reflective film includes a substrate, a microprism layer and a reflective layer. The thickness of the substrate is 10 μm to 1 mm, and the material includes a plastic substrate and a paper substrate; the microprism layer is arranged on the upper surface of the substrate, and the thickness thereof is 1 μm to 500 μm, and the material is a plastic material, and the microprism layer is a textured structure; the reflective layer is arranged on the upper surface of the microprism layer, and the thickness thereof is 1 μm to 500 μm, and the material includes a vacuum nickel-plated film, a vacuum aluminum-plated film, a vacuum silver-plated film, a polyester film coated with high-reflectivity silver, or a high-reflectivity multilayer dielectric film.

[0007] However, the connection effect between the above-mentioned photovoltaic module connecting welding ribbon and the battery cell is still poor, and the problem of saving silver paste is not well solved. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a photovoltaic module connecting welding ribbon and a fixing method thereof, wherein the cross-section of the photovoltaic module connecting welding ribbon includes a protruding structure, a rectangle or an oval shape, and conductive ink is printed on a battery cell and a certain pressure is applied to press and fix the photovoltaic module connecting welding ribbon and the battery cell, thereby achieving a firm connection between the photovoltaic module connecting welding ribbon and the battery cell, and effectively saving the amount of silver paste, thereby reducing production costs.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a photovoltaic module connecting welding ribbon, wherein the cross-section of the photovoltaic module connecting welding ribbon includes a protrusion structure, a rectangle or an oblate circle;

[0011] There are N protrusion structures, N is 3 to 100; the difference in distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 0.1μm to 400μm; the distance between the highest points of two adjacent protrusions is 0.1μm to 400μm; the aspect ratio of the rectangle is 0.05 to 0.3.

[0012] The cross section of the photovoltaic module connection welding strip of the present invention is a protrusion structure, and the protrusion structure has N, N is 3 to 100; the difference between the distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 0.1μm to 400μm; the distance between the highest points of two adjacent protrusions is 0.1μm to 400μm, which can fix the conductive particles in the conductive ink well, and then apply pressure from the air side to the battery cell side, and the conductive particles deform between the battery cell and the welding strip to generate sufficient resistance, conduct current, and at the same time, the conductive ink solidifies and fixes the conductive particles and the welding strip, so as to achieve a firm connection between the photovoltaic module connection welding strip and the battery cell. The cross section of the photovoltaic module connection welding strip is rectangular or oblate, and the aspect ratio of the rectangle or oblate is 0.05 to 0.3, and the contact area with the battery cell is large, so that the silver-free can be achieved while the battery cell is firmly fixed, which greatly reduces the cost of the photovoltaic module.

[0013] The protrusion structure described in the present invention has N numbers, where N is 3 to 100, for example, 3, 5, 10, 30, 50, 80, 90 or 100, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] The difference in distance between the recessed part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 0.1μm to 400μm, for example: it can be 0.1μm, 0.5μm, 10μm, 15μm, 20μm, 50μm, 80μm, 100μm, 300μm or 400μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] The distance between the highest points of two adjacent protrusions is 0.1μm to 400μm, for example, it can be 0.1μm, 0.55μm, 10μm, 60μm, 90μm, 100μm, 127μm, 200μm, 300μm or 400μm, etc., but it is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0016] The aspect ratio of the rectangle or oblate shape is 0.05 to 0.3, for example, it can be 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.25 or 0.3, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, there are N protrusion structures, where N is 3 to 10, for example, 3, 4, 5, 6, 7, 8, 9 or 10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] The difference in distance between the recessed part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 10 to 200 μm, for example, it can be 10 μm, 20 μm, 50 μm, 100 μm, 150 μm or 200 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0019] The distance between the highest points of two adjacent protrusions is 10 to 200 μm, for example, it can be 10 μm, 20 μm, 50 μm, 100 μm, 150 μm or 200 μm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the diameter of the welding ribbon for the photovoltaic module is 0.01-1 mm, for example, it can be 0.01 mm, 0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm or 1 mm, but it is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.1-0.3 mm.

[0021] In a second aspect, the present invention further provides a method for fixing the photovoltaic module connecting ribbon as described in the first aspect, the fixing method comprising:

[0022] (1) Printing conductive ink on the surface of the battery cell using a printing screen; the conductive ink contains conductive particles;

[0023] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.01 to 1 MPa, and pre-crosslinking the photovoltaic module connecting ribbon and the battery cell;

[0024] The pre-crosslinking includes any one of electron irradiation crosslinking, ion irradiation crosslinking, atomic irradiation crosslinking, neutron irradiation crosslinking, thermal irradiation crosslinking, thermal conduction crosslinking or electromagnetic irradiation crosslinking; the pre-crosslinking voltage is 250-400kV; the pre-crosslinking dose is 10-60KGY; the pre-crosslinking temperature is 80-200°C; the pre-crosslinking time is 0.1-1min.

[0025] The method for fixing the photovoltaic module connection welding strip of the present invention is simple to operate, and is performed by printing a conductive ink containing conductive particles on the surface of the battery cell; then, the photovoltaic module connection welding strip is pressed onto the conductive ink, and pre-crosslinked to fix the photovoltaic module connection welding strip and the battery cell. The fixing method of the present invention reduces the amount of silver paste used, reduces the cost of the photovoltaic module, and has a good fixing effect on the photovoltaic module connection welding strip and the battery cell, and has broad application prospects.

[0026] The pressure of the present invention is 0.01-1MPa, for example, it can be 0.01MPa, 0.05MPa, 0.1MPa, 0.3MPa, 0.5MPa, 0.8MPa or 1MPa, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. When the pressing pressure is small, the fixing effect of the photovoltaic module connecting the welding ribbon and the battery cell is poor, which will affect the final qualified rate of the photovoltaic module; when the pressing pressure is large, the conductive particles in the conductive ink will be broken, affecting the conductive effect of the photovoltaic module.

[0027] The pre-crosslinking voltage is 250-400 kV, for example, 250 kV, 260 kV, 300 kV, 320 kV, 350 kV, 370 kV or 400 kV, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] The pre-crosslinking dosage is 10-60 KGY, for example, 10 KGY, 15 KGY, 20 KGY, 30 KGY, 40 KGY, 45 KGY, 50 KGY or 60 KGY, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] The pre-crosslinking temperature is 80-200°C, for example, 80°C, 100°C, 110°C, 120°C, 150°C, 160°C, 170°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] The pre-crosslinking time is 0.1 to 1 min, for example, 0.1 s, 0.3 s, 0.5 s, 1 s, 10 s, 30 s, 50 s or 1 min, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the line width of a single conductive ink obtained after screen printing of the conductive ink in step (1) is 0.005 to 10 mm, for example, it can be 0.005 mm, 0.008 mm, 0.01 mm, 0.1 mm, 1 mm, 5 mm, 8 mm or 10 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; preferably 0.05 to 0.3 mm.

[0032] Preferably, the height of the single conductive ink strip is 0.0001 to 1 mm, for example, it can be 0.0001 mm, 0.001 mm, 0.01 mm, 0.05 mm, 0.3 mm, 0.5 mm, 0.8 mm or 1 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; preferably 0.001 to 0.05 mm.

[0033] Preferably, the conductive ink consists of a base resin and a curing agent.

[0034] Preferably, the curing agent accounts for 1 to 20% of the mass of the conductive ink binder, for example, it can be 1%, 3%, 5%, 10%, 12%, 15%, 18% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the matrix resin comprises liquid glue or hot melt glue.

[0036] Preferably, the liquid glue comprises any one of epoxy resin, unsaturated polyester resin, acrylic resin, silicone resin, polyurethane resin, phenoxy resin or alkyd resin, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of epoxy resin and unsaturated polyester resin, a combination of acrylic resin and silicone resin, a combination of polyurethane resin and phenoxy resin, or a combination of alkyd resin and epoxy resin.

[0037] Preferably, the hot melt temperature of the hot melt adhesive is 80-200° C., for example, 80° C., 100° C., 110° C., 120° C., 150° C., 160° C., 180° C. or 200° C., etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0038] The long-term operating temperature index is above 60°C, for example, it can be 60°C, 80°C, 105°C, 110°C, 120°C, 150°C, 160°C, 170°C or 180°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the curing agent includes any one of a latent curing agent, an isocyanate curing agent, a thermal alkaline curing agent, a thermal acidic curing agent or a photoinitiator, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of a latent curing agent and an isocyanate curing agent, a combination of a thermal alkaline curing agent and a thermal acidic curing agent, or a combination of a photoinitiator and a thermal alkaline curing agent.

[0040] Preferably, the latent curing agent includes any one of a latent anionic polymerization catalytic curing agent, a latent cationic polymerization catalytic curing agent or a latent addition polymerization curing agent, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of a latent anionic polymerization catalytic curing agent and a latent cationic polymerization catalytic curing agent, a combination of a latent addition polymerization curing agent and a latent anionic polymerization catalytic curing agent, or a combination of a latent cationic polymerization catalytic curing agent and a latent addition polymerization curing agent.

[0041] Preferably, the latent curing agent includes any one of a coated amine curing agent, a coated urea curing agent, an anhydride curing agent, a phenolic curing agent, a polythiol curing agent, an anionic polymerizing curing agent or a cationic polymerizing curing agent, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of a coated amine curing agent and a coated urea curing agent, a combination of an anhydride curing agent and a phenolic curing agent, a combination of a polythiol curing agent and an anionic polymerizing curing agent, or a combination of a cationic polymerizing curing agent and a coated amine curing agent.

[0042] Preferably, the latent cationic polymerization catalytic curing agent includes any one of boron trifluoride amine complex, polythiol aryl diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, triaryl selenium salt and iron-arene complex or amine-blocked Lewis acid salt, or a combination of at least two thereof, wherein typical but non-limiting combinations include a combination of boron trifluoride amine complex and polythiol aryl diazonium salt, a combination of diaryl iodonium salt and triaryl sulfonium salt, a combination of triaryl selenium salt and iron-arene complex and amine-blocked Lewis acid salt, or a combination of polythiol aryl diazonium salt and triaryl sulfonium salt.

[0043] Preferably, the thermal initiation temperature of the latent cationic polymerization catalytic curing agent is 80-200°C, for example, it can be 80°C, 110°C, 120°C, 150°C, 160°C, 180°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the photosensitizer has a photosensitivity wavelength of 250 nm to 500 nm, for example, 250 nm, 260 nm, 300 nm, 320 nm, 350 nm, 400 nm, 450 nm or 500 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the photoinitiator includes benzoin and its derivatives photoinitiator, benzil and its derivatives photoinitiator, acetophenone derivatives photoinitiator, α-hydroxyketone derivatives photoinitiator, α-aminoketone derivatives photoinitiator, acylphosphine oxide photoinitiator, sulfur-containing photoinitiator, benzophenone and its derivatives photoinitiator, thioxanthone and its derivatives photoinitiator, anthraquinone and its derivatives photoinitiator, aryldiazonium salt photoinitiator, diaryliodonium salt photoinitiator, triarylsulfonium salt photoinitiator, arylferrocenium salt photoinitiator, camphorquinone photoinitiator or titanocene photoinitiator. The photoinitiator may be a photoinitiator selected from the group consisting of any one or a combination of at least two of the photoinitiators, wherein typical but non-limiting combinations include a combination of benzoin and its derivatives photoinitiators and benzil and its derivatives photoinitiators, a combination of acetophenone derivatives photoinitiators and α-hydroxyketone derivatives photoinitiators, a combination of α-aminoketone derivatives photoinitiators and acylphosphine oxide photoinitiators, a combination of sulfur-containing photoinitiators and benzophenone and its derivatives photoinitiators, a combination of thioxanthone and its derivatives photoinitiators and anthraquinone and its derivatives photoinitiators, or a combination of aryldiazonium salt photoinitiators and diaryliodonium salt photoinitiators.

[0046] Preferably, the conductive particles in step (1) account for 5 to 30% of the volume of the conductive ink, for example, 5%, 8%, 10%, 13%, 20%, 25%, 38% or 30%, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the conductive particles in step (1) include small balls with a metal coating.

[0048] The small ball with metal coating described in the present invention can be a hollow small ball or a solid small ball.

[0049] Preferably, the metal plating layer comprises any one of an iron layer, a nickel layer, a copper layer, a zinc layer, an aluminum layer, a silver layer or a gold layer, or a combination of at least two of them, wherein a typical but non-limiting combination comprises a combination of a nickel layer and a gold layer, a combination of a silver layer and a nickel layer, or a combination of a copper layer and a nickel layer. These plating layers have very low ductility and activity and will not chemically react with other materials.

[0050] Preferably, the total thickness of the metal coating is 0.001 to 0.1 μm, for example, it can be 0.001 μm, 0.01 μm, 0.03 μm, 0.05 μm, 0.07 μm, 0.09 μm or 0.1 μm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.03 to 0.06 μm.

[0051] Preferably, the thickness ratio of the nickel layer and the gold layer is (2-10):1, for example, it can be 2:1, 3:1, 5:1, 7:1, 7.5:1, 8:1, 9:1 or 10:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] Preferably, the diameter of the spheres is 1 to 200 μm, for example, 1 μm, 3 μm, 5 μm, 8 μm, 9 μm, 10 μm, 50 μm, 100 μm or 200 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 5 to 150 μm.

[0053] Preferably, the material of the ball includes any one of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, silicone, glass, nylon, polyimide, fluorine-containing resin, EVA, POE, ABS plastic or EBA plastic.

[0054] Preferably, the pressing pressure in step (2) is 0.05-0.2 MPa, for example, 0.05 MPa, 0.1 MPa, 0.13 MPa, 0.15 MPa, 0.18 MPa or 0.2 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the temperature of the radiation cross-linking in step (2) is 100-150°C, for example, it can be 100°C, 120°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the radiation cross-linking time in step (2) is 0.1 to 0.5 s, for example, 0.1 s, 0.15 s, 0.2 s, 0.3 s, 0.35 s, 0.4 s, 0.45 s, 0.48 s or 0.5 s, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0057] As a preferred technical solution of the present invention, the fixing method includes:

[0058] (1) Printing conductive ink on the surface of the battery cell using a printing screen; the conductive ink contains conductive particles;

[0059] The conductive particles account for 5 to 30% of the volume of the conductive ink; the conductive particles include small balls with metal coatings; the metal coatings include any one of an iron layer, a nickel layer, a copper layer, a zinc layer, an aluminum layer, a silver layer or a gold layer, or a combination of at least two of them; the total thickness of the metal coating is 0.001 to 0.1 μm; the thickness ratio of the nickel layer to the gold layer is (2 to 10): 1; the diameter of the small balls is 1 to 200 μm; the material of the small balls includes any one of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, silicone, glass, nylon, polyimide, fluorine-containing resin, EVA, POE, ABS plastic or EBA plastic;

[0060] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 0.005 to 10 mm; the height of the single conductive ink is 0.0001 to 1 mm;

[0061] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1-20% of the mass of the conductive ink binder; the base resin includes liquid glue or hot melt glue; the liquid glue includes any one of epoxy resin, unsaturated polyester resin, acrylic resin, silicone resin, polyurethane resin, phenoxy resin or alkyd resin or a combination of at least two; the hot melt temperature of the hot melt glue is 80-200°C, and the long-term working temperature index is above 60°C; the curing agent includes any one of latent curing agent, isocyanate curing agent, thermal alkaline curing agent, thermal acid curing agent or photoinitiator or a combination of at least two; the photosensitive wavelength of the photoinitiator is 250nm-500nm;

[0062] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.01 to 1 MPa, and pre-crosslinking the photovoltaic module connecting ribbon and the battery cell;

[0063] The pre-crosslinking includes any one of electron irradiation crosslinking, ion irradiation crosslinking, atomic irradiation crosslinking, neutron irradiation crosslinking, thermal irradiation crosslinking, thermal conduction crosslinking or electromagnetic irradiation crosslinking; the pre-crosslinking voltage is 250-400kV; the pre-crosslinking dose is 10-60KGY; the pre-crosslinking temperature is 80-200°C; the pre-crosslinking time is 0.1-1min.

[0064] In a third aspect, the present invention further provides a use of a fixing assembly of photovoltaic module connecting welding strips and battery cells obtained by the method for fixing photovoltaic module connecting welding strips as described in the second aspect, wherein the fixing assembly is used for BC modules, perovskite modules, HJT modules without main grid, or TOPCon modules without main grid.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] (1) The cross-section of a photovoltaic module connecting welding ribbon provided by the present invention is a protruding structure, rectangular or oblate. When the photovoltaic module connecting welding ribbon is fixed by conductive ink, the conductive particles are deformed between the battery cell and the welding ribbon to generate sufficient resistance to conduct current. Moreover, the photovoltaic module connecting welding ribbon and the battery cell are pressed together by a certain pressure. The deformed conductive particles have a certain internal resistance in the conductive channel, which can achieve stable conduction.

[0067] (2) After the photovoltaic module provided by the present invention is connected with the welding strip and the solar cell, the module is finally pressed together, and the curing rate of the finished module can reach more than 80%.

[0068] (3) The method for fixing the photovoltaic module connecting welding ribbon provided by the present invention can effectively fix the photovoltaic module connecting welding ribbon and the battery cell while reducing the amount of silver paste used, and is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of the fixing structure of the photovoltaic module connecting the welding strip and the battery cell in Example 1 of the present invention.

[0070] Figure 2 It is a schematic diagram of the fixing structure of the photovoltaic module connecting the welding strip and the battery cell in Example 2 of the present invention.

[0071] In the figure: 1-conductive ink; 2-conductive particles; 3-photovoltaic module connecting welding ribbon with a protruding structure in cross section; 4-battery cell; 5-photovoltaic module connecting welding ribbon with a rectangular cross section. DETAILED DESCRIPTION

[0072] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0073] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0074] Example 1

[0075] This embodiment provides a photovoltaic module connecting welding strip, and the fixing structure diagram of the photovoltaic module connecting welding strip and the battery cell 4 is as follows Figure 1 shown.

[0076] The photovoltaic component connecting welding strip is a photovoltaic component connecting welding strip 3 with a protruding structure in cross section; there are N protruding structures, N is 8; the difference in distance between the recessed part of the protruding structure and the highest point of the protruding structure and the center of the welding strip cross section is 15 μm; the distance between the highest points of two adjacent protrusions is 30 μm.

[0077] The diameter of the photovoltaic module connecting welding ribbon 3 with a protruding structure in cross section is 0.3 mm.

[0078] This embodiment also provides a method for fixing the photovoltaic module connecting welding ribbon 3 having a protruding cross-section, the fixing method comprising:

[0079] (1) Printing conductive ink 1 on the surface of the battery cell 4 using a printing screen;

[0080] The conductive ink 1 contains conductive particles 2; the conductive particles 2 account for 10% of the volume of the conductive ink 1; the conductive particles 2 include solid balls with a nickel layer; the total thickness of the nickel layer is 0.01 μm; the diameter of the solid balls is 1 μm; the material of the solid balls is polyethylene;

[0081] The line width of a single conductive ink 1 obtained after the conductive ink 1 is printed on a printing screen is 0.01 mm; the height of the single conductive ink 1 is 0.01 mm;

[0082] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 10% of the mass of the conductive ink binder; the base resin is an unsaturated polyester resin, which is the unsaturated polyester resin described in Preparation Example 1 in CN202310080824.3; the curing agent is a diaryl iodonium salt;

[0083] (2) Pressing the photovoltaic module connecting welding ribbon 3 with a protruding cross-section onto the conductive ink 1 with a pressure of 0.1 MPa, and pre-crosslinking, so as to fix the photovoltaic module connecting welding ribbon 3 with a protruding cross-section and the battery cell 4;

[0084] The pre-crosslinking is electron irradiation crosslinking; the pre-crosslinking voltage is 300 kV; the pre-crosslinking dose is 20 KGY; the pre-crosslinking temperature is 100° C.; and the pre-crosslinking time is 0.6 min.

[0085] Example 2

[0086] This embodiment provides a photovoltaic module connecting welding strip, and the fixing structure diagram of the photovoltaic module connecting welding strip and the battery cell 4 is as follows Figure 2 shown.

[0087] The photovoltaic module connecting welding ribbon is a photovoltaic module connecting welding ribbon 5 with a rectangular cross section; the aspect ratio of the rectangle is 0.1.

[0088] The diameter of the photovoltaic module connecting welding ribbon 5 with a rectangular cross section is 0.1 mm.

[0089] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0090] (1) Printing conductive ink 1 on the surface of the battery cell 4 using a printing screen;

[0091] The conductive ink 1 contains conductive particles 2; the conductive particles 2 account for 20% of the volume of the conductive ink 1; the conductive particles 2 include hollow spheres with a silver layer; the total thickness of the silver layer is 0.05 μm; the diameter of the hollow spheres is 5 μm; the material of the hollow spheres is polypropylene;

[0092] The line width of a single conductive ink 1 obtained after the conductive ink 1 is printed on a printing screen is 3 mm; the height of the single conductive ink 1 is 0.03 mm;

[0093] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1 to 20% of the mass of the conductive ink binder; the base resin is acrylic resin 73332-S-60 (Changxing Chemical); the curing agent is a coated urea curing agent;

[0094] (2) Pressing the photovoltaic module connecting welding ribbon 5 with a rectangular cross section onto the conductive ink 1 with a pressure of 0.07 MPa, and pre-crosslinking, so as to fix the photovoltaic module connecting welding ribbon 5 with a rectangular cross section and the battery cell 4;

[0095] The pre-crosslinking is ion irradiation crosslinking; the pre-crosslinking voltage is 280 kV; the pre-crosslinking dose is 17 KGY; the pre-crosslinking temperature is 110° C.; and the pre-crosslinking time is 0.2 min.

[0096] Example 3

[0097] This embodiment provides a photovoltaic module connecting welding strip, the cross section of which is a protrusion structure; the protrusion structure has N, N is 30; the difference between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 400 μm; the distance between the highest points of two adjacent protrusions is 5 μm. The diameter of the photovoltaic module connecting welding strip is 0.3 mm.

[0098] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0099] (1) Printing conductive ink on the surface of the battery cell using a printing screen;

[0100] The conductive ink contains conductive particles; the conductive particles account for 5% of the volume of the conductive ink; the conductive particles include solid balls with metal coatings; the metal coating is an aluminum layer; the total thickness of the metal coating is 0.1 μm; the diameter of the solid balls is 8 μm; the material of the solid balls is polystyrene;

[0101] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 0.3 mm; the height of the single conductive ink is 0.07 mm;

[0102] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1-20% of the mass of the conductive ink binder; the base resin is the epoxy resin Shinnippon Steel & Sumikin Chemical YP-50; the curing agent is a polythiol curing agent;

[0103] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.02 MPa and pre-crosslinking the photovoltaic module connecting ribbon to the battery cell;

[0104] The pre-crosslinking is neutron irradiation crosslinking; the pre-crosslinking voltage is 250kV; the pre-crosslinking dose is 60KGY; the pre-crosslinking temperature is 200°C; and the pre-crosslinking time is 1min.

[0105] Example 4

[0106] This embodiment provides a photovoltaic module connecting welding strip, the cross section of the photovoltaic module connecting welding strip is a protrusion structure; the protrusion structure has N, N is 42; the difference between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 0.1 μm; the distance between the highest points of two adjacent protrusions is 0.1 μm. The diameter of the photovoltaic module connecting welding strip is 0.05 mm.

[0107] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0108] (1) Printing conductive ink on the surface of the battery cell using a printing screen;

[0109] The conductive ink contains conductive particles; the conductive particles account for 30% of the volume of the conductive ink; the conductive particles include hollow spheres with metal coating; the metal coating is a copper layer; the total thickness of the metal coating is 0.04 μm; the diameter of the hollow sphere is 2 μm; the material of the hollow sphere is polyethylene terephthalate;

[0110] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 10 mm; the height of the single conductive ink is 1 mm;

[0111] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1 to 20% of the mass of the conductive ink binder; the base resin is an unsaturated polyester resin, which is the unsaturated polyester resin described in Preparation Example 1 in CN202310080824.3; the curing agent is an anionic polymerization curing agent;

[0112] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.01 MPa and pre-crosslinking the photovoltaic module connecting ribbon to the battery cell;

[0113] The pre-crosslinking is thermal radiation crosslinking; the pre-crosslinking voltage is 400 kV; the pre-crosslinking dose is 10 KGY; the pre-crosslinking temperature is 80° C.; and the pre-crosslinking time is 0.1 min.

[0114] Example 5

[0115] This embodiment provides a photovoltaic module connecting welding strip, the cross section of the photovoltaic module connecting welding strip is a protrusion structure; the protrusion structure has N, N is 50; the difference between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 21μm; the distance between the highest points of two adjacent protrusions is 400μm. The diameter of the photovoltaic module connecting welding strip is 0.06mm.

[0116] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0117] (1) Printing conductive ink on the surface of the battery cell using a printing screen;

[0118] The conductive ink contains conductive particles; the conductive particles account for 12.5% ​​of the volume of the conductive ink; the conductive particles include hollow spheres with a silver layer; the total thickness of the silver layer is 0.008 μm; the diameter of the hollow spheres is 3.6 μm; the material of the hollow spheres is ABS plastic;

[0119] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 0.008 mm; the height of the single conductive ink is 0.0004 mm;

[0120] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1 to 20% of the mass of the conductive ink binder; the base resin is an organic silicone resin; and the curing agent is a boron trifluoride amine complex;

[0121] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.06 MPa and pre-crosslinking the photovoltaic module connecting ribbon to the battery cell;

[0122] The pre-crosslinking is electromagnetic radiation crosslinking; the pre-crosslinking voltage is 288 kV; the pre-crosslinking dose is 16.7 KGY; the pre-crosslinking temperature is 136° C.; and the pre-crosslinking time is 0.17 min.

[0123] Example 6

[0124] This embodiment provides a photovoltaic module connecting welding strip, wherein the cross section of the photovoltaic module connecting welding strip is a rectangle, the aspect ratio of the rectangle is 0.05, and the diameter of the photovoltaic module connecting welding strip is 0.25 mm.

[0125] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0126] (1) Printing conductive ink on the surface of the battery cell using a printing screen;

[0127] The conductive ink contains conductive particles; the conductive particles account for 22% of the volume of the conductive ink; the conductive particles include solid balls with a nickel layer; the total thickness of the nickel layer is 0.004 μm; the diameter of the solid balls is 15 μm; the material of the solid balls is EBA plastic;

[0128] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 1.3 mm; the height of the single conductive ink is 0.52 mm;

[0129] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 1 to 20% of the mass of the conductive ink binder; the base resin is a polyurethane resin; the curing agent is a diaryliodonium salt;

[0130] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.06 MPa and pre-crosslinking the photovoltaic module connecting ribbon to the battery cell;

[0131] The pre-crosslinking is atomic irradiation crosslinking; the pre-crosslinking voltage is 330 kV; the pre-crosslinking dose is 10.5 KGY; the pre-crosslinking temperature is 88° C.; and the pre-crosslinking time is 0.161 min.

[0132] Example 7

[0133] The present embodiment provides a photovoltaic module connecting welding ribbon, wherein the photovoltaic module connecting welding ribbon is a photovoltaic module connecting welding ribbon with an oblate cross-section; the aspect ratio of the oblate cross-section is 0.15.

[0134] The diameter of the photovoltaic module connecting welding ribbon with an oblate cross-section is 0.13 mm.

[0135] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0136] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0137] The conductive ink contains conductive particles; the conductive particles account for 6% of the conductive ink mass and volume; the conductive particles include hollow spheres with metal coating; the metal coating is an iron layer; the total thickness of the metal coating is 0.007 μm; the diameter of the hollow sphere is 8.3 μm; the material of the hollow sphere is EBA plastic;

[0138] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 0.03 mm; the height of the single conductive ink is 0.5 mm;

[0139] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 10% of the mass of the conductive ink binder; the base resin is a phenoxy resin; and the curing agent is an anionic polymerizing curing agent;

[0140] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.2 MPa, and irradiating for pre-crosslinking to achieve fixation of the photovoltaic module connecting ribbon and the battery cell;

[0141] The irradiation pre-crosslinking is neutron irradiation crosslinking; the voltage of the irradiation pre-crosslinking is 390 kV; the dose of the irradiation pre-crosslinking is 50 KGY; the temperature of the irradiation pre-crosslinking is 180° C.; and the time of the irradiation pre-crosslinking is 0.1 min.

[0142] Example 8

[0143] The present embodiment provides a photovoltaic module connecting welding ribbon, wherein the photovoltaic module connecting welding ribbon is a photovoltaic module connecting welding ribbon with a rectangular cross-section; the aspect ratio of the oblate shape is 0.18.

[0144] The diameter of the photovoltaic module connecting welding ribbon with a rectangular cross section is 0.1mm.

[0145] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0146] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0147] The conductive ink contains conductive particles; the conductive particles account for 8% of the conductive ink mass and volume; the conductive particles include solid balls with metal coating; the metal coating is a zinc layer; the total thickness of the metal coating is 0.08 μm; the diameter of the solid balls is 8.1 μm; the material of the solid balls is polyimide;

[0148] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 0.13 mm; the height of the single conductive ink is 0.37 mm;

[0149] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 20% of the mass of the conductive ink binder; the base resin is an unsaturated polyester resin, which is the unsaturated polyester resin described in Preparation Example 1 in CN202310080824.3; the curing agent is a triaryl selenium salt and an iron-arene complex;

[0150] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.5 MPa, and irradiating for pre-crosslinking to achieve fixation of the photovoltaic module connecting ribbon and the battery cell;

[0151] The irradiation pre-crosslinking is neutron irradiation crosslinking; the voltage of the irradiation pre-crosslinking is 370 kV; the dose of the irradiation pre-crosslinking is 40 KGY; the temperature of the irradiation pre-crosslinking is 170° C.; and the time of the irradiation pre-crosslinking is 0.2 min.

[0152] Example 9

[0153] The present embodiment provides a photovoltaic module connecting welding ribbon, wherein the photovoltaic module connecting welding ribbon is a photovoltaic module connecting welding ribbon with an oblate cross-section; the aspect ratio of the oblate cross-section is 0.22.

[0154] The diameter of the photovoltaic module connecting welding ribbon with an oblate cross-section is 0.1 mm.

[0155] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0156] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0157] The conductive ink contains conductive particles; the conductive particles account for 13% of the conductive ink mass and volume; the conductive particles include hollow spheres with metal coating; the metal coating is a gold layer; the total thickness of the gold layer is 0.02 μm; the diameter of the hollow sphere is 7 μm; the material of the hollow sphere is polyvinyl chloride;

[0158] The line width of a single conductive ink obtained after the conductive ink is printed on the printing screen is 0.23 mm; the height of the single conductive ink is 0.007 mm;

[0159] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 15% of the mass of the conductive ink binder; the base resin is an alkyd resin; the curing agent is a photoinitiator; the photosensitive wavelength of the photoinitiator is 500nm; the photoinitiator is a diaryliodonium salt photoinitiator;

[0160] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.7 MPa, and irradiating for pre-crosslinking to achieve fixation of the photovoltaic module connecting ribbon and the battery cell;

[0161] The irradiation pre-crosslinking is neutron irradiation crosslinking; the voltage of the irradiation pre-crosslinking is 330 kV; the dose of the irradiation pre-crosslinking is 45 KGY; the temperature of the irradiation pre-crosslinking is 150° C.; and the time of the irradiation pre-crosslinking is 0.3 min.

[0162] Example 10

[0163] The present embodiment provides a photovoltaic module connecting welding ribbon, wherein the photovoltaic module connecting welding ribbon is a photovoltaic module connecting welding ribbon with a rectangular cross-section; the aspect ratio of the oblate shape is 0.27.

[0164] The diameter of the photovoltaic module connecting welding ribbon with a rectangular cross section is 0.05mm.

[0165] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0166] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0167] The conductive ink contains conductive particles; the conductive particles account for 15% of the conductive ink mass and volume; the conductive particles include hollow spheres with metal coating; the metal coating is a nickel layer; the total thickness of the nickel layer is 0.001 μm; the diameter of the hollow sphere is 200 μm; the material of the hollow sphere is EVA;

[0168] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 3 mm; the height of the single conductive ink is 0.01 mm;

[0169] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 10.6% of the mass of the conductive ink binder; the base resin is the epoxy resin Shinnippon Steel & Sumikin Chemical YP-50; the curing agent is a photoinitiator; the photosensitive wavelength of the photoinitiator is 250nm; the photoinitiator is a sulfur-containing photoinitiator;

[0170] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.9 MPa, and irradiating for pre-crosslinking to achieve fixation of the photovoltaic module connecting ribbon and the battery cell;

[0171] The irradiation pre-crosslinking is neutron irradiation crosslinking; the voltage of the irradiation pre-crosslinking is 350 kV; the dose of the irradiation pre-crosslinking is 30 KGY; the temperature of the irradiation pre-crosslinking is 130° C.; and the time of the irradiation pre-crosslinking is 0.5 min.

[0172] Embodiment 11

[0173] The present embodiment provides a photovoltaic module connecting welding strip, which is a photovoltaic module connecting welding strip with a protruding structure in cross section; there are N protruding structures, and N is 88; the difference in distance between the recessed part of the protruding structure and the highest point of the protruding structure and the center of the welding strip cross section is 5μm; the distance between the highest points of two adjacent protrusions is 38μm.

[0174] The diameter of the photovoltaic module connecting welding ribbon with a protruding cross-section is 0.13 mm.

[0175] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0176] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0177] The conductive ink contains conductive particles; the conductive particles account for 25% of the conductive ink mass and volume; the conductive particles include hollow spheres with metal coatings; the metal coatings are nickel layers and gold layers arranged in sequence; the total thickness of the metal coatings is 0.05 μm; the thickness ratio of the nickel layer to the gold layer is 10:1; the diameter of the hollow sphere is 80 μm; the material of the hollow sphere is POE;

[0178] The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen is 3.3 mm; the height of the single conductive ink is 0.05 mm;

[0179] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 12.6% of the mass of the conductive ink binder; the base resin is a hot melt adhesive; the hot melt temperature of the hot melt adhesive is 200°C, and the long-term working temperature index is above 60°C; the curing agent is a phenolic curing agent;

[0180] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 1 MPa, and performing irradiation pre-crosslinking to fix the photovoltaic module connecting ribbon and the battery cell;

[0181] The radiation pre-crosslinking is thermal radiation crosslinking; the voltage of the radiation pre-crosslinking is 290 kV; the dose of the radiation pre-crosslinking is 20 KGY; the temperature of the radiation pre-crosslinking is 120° C.; and the time of the radiation pre-crosslinking is 1 min.

[0182] Example 12

[0183] The present embodiment provides a photovoltaic module connecting welding strip, which is a photovoltaic module connecting welding strip with a protruding structure in cross section; there are N protruding structures, where N is 100; the difference in distance between the recessed part of the protruding structure and the highest point of the protruding structure and the center of the welding strip cross section is 25 μm; the distance between the highest points of two adjacent protrusions is 42 μm.

[0184] The diameter of the photovoltaic module connecting welding ribbon with a protruding cross-section is 0.22 mm.

[0185] This embodiment also provides a method for fixing the above-mentioned photovoltaic module connection welding strip, and the fixing method includes:

[0186] (1) Printing conductive ink on the surface of the cell using a printing screen and then pre-curing it;

[0187] The conductive ink contains conductive particles; the conductive particles account for 30% of the conductive ink mass and volume; the conductive particles include hollow spheres with metal coatings; the metal coatings are nickel layers and gold layers arranged in sequence; the total thickness of the metal coatings is 0.1 μm; the thickness ratio of the nickel layer to the gold layer is 2.9:1; the diameter of the hollow sphere is 3 μm; the material of the hollow sphere is polyethylene;

[0188] The line width of a single conductive ink obtained after the conductive ink is printed on the printing screen is 5.3 mm; the height of the single conductive ink is 0.7 mm;

[0189] The conductive ink is composed of a base resin and a curing agent; the curing agent accounts for 11.5% of the mass of the conductive ink binder; the base resin is a hot melt adhesive; the hot melt temperature of the hot melt adhesive is 80°C, and the long-term working temperature index is above 60°C; the curing agent is a cationic polymerization curing agent;

[0190] (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.03 MPa, and irradiating for pre-crosslinking to achieve fixation of the photovoltaic module connecting ribbon and the battery cell;

[0191] The radiation pre-crosslinking is heat conduction crosslinking; the voltage of the radiation pre-crosslinking is 280 kV; the dose of the radiation pre-crosslinking is 10 KGY; the temperature of the radiation pre-crosslinking is 100° C.; and the time of the radiation pre-crosslinking is 0.7 min.

[0192] Comparative Example 1

[0193] This comparative example provides a photovoltaic module connecting welding strip, the photovoltaic module connecting welding strip has a circular cross section and no protrusion structure, and is connected by silver paste dispensing and then fixed by heat curing. The rest is the same as Example 1.

[0194] Comparative Example 2

[0195] This comparative example provides a photovoltaic module connecting welding strip, which is the same as Example 1 except that the difference in distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the welding strip cross section is 0.01 μm.

[0196] Comparative Example 3

[0197] This comparative example provides a photovoltaic module connecting welding strip, which is the same as Example 1 except that the difference in distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the welding strip cross section is 433 μm.

[0198] Comparative Example 4

[0199] This comparative example provides a method for fixing a photovoltaic module connection welding strip, and the fixing method is the same as Example 1 except that the pressure in step (2) is 0.001 MPa.

[0200] Comparative Example 5

[0201] This comparative example provides a method for fixing a photovoltaic module connecting welding strip, and the fixing method is the same as Example 1 except that the pressure in step (2) is 2 MPa.

[0202] The amount of silver (nickel / gold), resistance, bonding strength, and post-DH2000 attenuation of the photovoltaic module connection ribbon and battery cell fixing products obtained in the above embodiments and comparative examples were tested. The results are shown in Table 1.

[0203] The test method is:

[0204] (1) Conductivity test

[0205] After curing is completed, use a microresistance meter to test the resistance value of two adjacent main grids.

[0206] (2) Bond strength measurement (N / 1.5mm):

[0207] Prepare a cell that has been hot-pressed at 180°C, 2MPa, and 10s, bend the end of the solder strip 180°, fix it on the fixture of the tensile machine, and stretch it 180° at a tensile speed of 30mm / s to measure the peel strength. At this time, if the peel force is ≥0.3N / 1.5mm, it means that the test has passed.

[0208] (3) Component end aging test

[0209] Component manufacturing method: Use automatic pressing equipment to make a 2*3 combination of 6 battery cells, and use EVA, glass, and backplane to encapsulate and laminate them into components; test the contact resistance of the 2*3 component, where DH1000, DH2000, and DH3000 refer to the test end resistance after being placed at 85°C and 85% relative humidity for 1000 hours, 2000 hours, and 3000 hours, respectively, and calculate the relative increase in resistance; refer to IEC61215 standard for details.

[0210] Table 1

[0211]

[0212] "(X)" in Table 1 indicates that the effect is not good and does not meet customer requirements.

[0213] From Table 1 we can see that:

[0214] (1) Based on Examples 1 to 12, it can be seen that the amount of silver (nickel / gold) used in the photovoltaic module connection welding ribbon provided by the present invention is less than 2.6 mg / W, the resistance is less than 38 mΩ, the bonding strength is high, and the attenuation after DH2000 is small, and the application range is wide;

[0215] (2) It can be seen from the comprehensive comparison between Example 1 and Comparative Example 1 that the resistance difference between Example 1 and Comparative Example 1 is small, and Example 1 saves more than 70% of silver and can maintain similar conductivity and aging resistance as Comparative Example 1;

[0216] (3) It can be seen from Example 1 and Comparative Examples 2 to 5 that if the protrusion of the welding strip is too large or too small, it will obviously affect the conductive performance. In Comparative Example 4, the pressure is insufficient, and the conductive balls cannot fill the gaps, which affects the conductive performance. In Comparative Example 5, the pressure is too high, which causes the balls to rupture and seriously affects the conductive performance.

[0217] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A photovoltaic module connecting ribbon, characterized in that: The cross-section of the photovoltaic module connecting welding strip includes a protrusion structure, a rectangle or an oblate circle; There are N protrusion structures, N is 3 to 100; the difference between the distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 0.1 μm to 400 μm; the distance between the highest points of two adjacent protrusions is 0.1 μm to 400 μm; The aspect ratio of the rectangle or oblate shape is 0.05 to 0.

3.

2. The photovoltaic module connecting ribbon according to claim 1, characterized in that: There are N protrusion structures, N is 3-10; the difference in distance between the concave part of the protrusion structure and the highest point of the protrusion structure and the center of the cross section of the welding strip is 10-200 μm; the distance between the highest points of two adjacent protrusions is 10-200 μm.

3. The photovoltaic module connecting welding strip according to claim 1 or 2, characterized in that: The diameter of the photovoltaic module connecting welding strip is 0.01-1 mm, preferably 0.1-0.3 mm.

4. A method for fixing a photovoltaic module connecting welding strip according to any one of claims 1 to 3, characterized in that: The fixing method comprises: (1) Printing conductive ink on the surface of the battery cell using a printing screen; the conductive ink contains conductive particles; (2) Pressing the photovoltaic module connecting ribbon onto the conductive ink with a pressure of 0.01 to 1 MPa, and pre-crosslinking the photovoltaic module connecting ribbon and the battery cell; The pre-crosslinking includes any one of electron irradiation crosslinking, ion irradiation crosslinking, atomic irradiation crosslinking, neutron irradiation crosslinking, thermal irradiation crosslinking, thermal conduction crosslinking or electromagnetic irradiation crosslinking; the pre-crosslinking voltage is 250-400kV; the pre-crosslinking dose is 10-60KGY; the pre-crosslinking temperature is 80-200°C; the pre-crosslinking time is 0.1-1min.

5. The fixing method according to claim 4, characterized in that: The line width of a single conductive ink obtained after the conductive ink is printed on a printing screen in step (1) is 0.005 to 10 mm, preferably 0.05 to 0.3 mm; Preferably, the height of the single conductive ink strip is 0.0001 to 1 mm, preferably 0.001 to 0.05 mm; Preferably, the conductive ink is composed of a base resin and a curing agent; Preferably, the curing agent accounts for 1 to 20% of the mass of the conductive ink; Preferably, the matrix resin comprises liquid glue or hot melt glue; Preferably, the liquid glue comprises any one of epoxy resin, unsaturated polyester resin, acrylic resin, silicone resin, polyurethane resin, phenoxy resin or alkyd resin, or a combination of at least two thereof; Preferably, the hot melt temperature of the hot melt adhesive is 80-200°C, and the long-term working temperature index is above 60°C; Preferably, the curing agent includes any one or a combination of at least two of a latent curing agent, an isocyanate curing agent, a thermal alkaline curing agent, a thermal acidic curing agent or a photoinitiator; Preferably, the latent curing agent includes any one of a latent anionic polymerization catalytic curing agent, a latent cationic polymerization catalytic curing agent or a latent addition polymerization curing agent, or a combination of at least two thereof; Preferably, the latent curing agent includes any one or a combination of at least two of a coated amine curing agent, a coated urea curing agent, an anhydride curing agent, a phenolic curing agent, a polythiol curing agent, an anionic polymerizing curing agent or a cationic polymerizing curing agent; Preferably, the latent cationic polymerization catalytic curing agent includes any one or a combination of at least two of boron trifluoride amine complex, polythiol aromatic diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, triaryl selenium salt and iron-arene complex or amine-blocked Lewis acid salt; Preferably, the thermal initiation temperature of the latent cationic polymerization catalytic curing agent is 80 to 200°C; Preferably, the photosensitive wavelength of the photoinitiator is 250nm to 500nm; Preferably, the photoinitiator includes any one of benzoin and its derivatives photoinitiators, benzil and its derivatives photoinitiators, acetophenone derivatives photoinitiators, α-hydroxyketone derivatives photoinitiators, α-aminoketone derivatives photoinitiators, acylphosphine oxide photoinitiators, sulfur-containing photoinitiators, benzophenone and its derivatives photoinitiators, thioxanthone and its derivatives photoinitiators, anthraquinone and its derivatives photoinitiators, aromatic diazonium salt photoinitiators, diaryl iodonium salt photoinitiators, triaryl sulfonium salt photoinitiators, aromatic ferrocenium salt photoinitiators, camphorquinone photoinitiators or titanocenium photoinitiators, or a combination of at least two thereof.

6. The fixing method according to claim 4 or 5, characterized in that: The conductive particles in step (1) account for 5 to 30% of the volume of the conductive ink.

7. The fixing method according to any one of claims 4 to 6, characterized in that: The conductive particles in step (1) include small balls with a metal coating; Preferably, the metal plating layer includes any one of an iron layer, a nickel layer, a copper layer, a zinc layer, an aluminum layer, a silver layer or a gold layer, or a combination of at least two thereof; Preferably, the total thickness of the metal coating is 0.001 to 0.1 μm, preferably 0.03 to 0.06 μm; Preferably, the thickness ratio of the nickel layer to the gold layer is (2-10):

1.

8. The fixing method according to claim 7, characterized in that: The diameter of the sphere is 1 to 200 μm, preferably 5 to 150 μm; Preferably, the material of the ball includes any one of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, silicone, glass, nylon, polyimide, fluorine-containing resin, EVA, POE, ABS plastic or EBA plastic.

9. The fixing method according to any one of claims 4 to 8, characterized in that: The pressing pressure in step (2) is 0.05-0.2 MPa; Preferably, the temperature of the radiation cross-linking in step (2) is 100-150°C; Preferably, the radiation cross-linking time in step (2) is 0.1 to 0.5 s.

10. Use of a fixing assembly for photovoltaic module connecting welding strips and solar cells obtained by the fixing method for photovoltaic module connecting welding strips as claimed in any one of claims 4 to 9, characterized in that: The fixing component is used for a BC component, a perovskite component, a HJT component without a main grid or a TOPCon component without a main grid.

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