A high water-resistance photovoltaic module and a preparation method thereof

Abstract

The present application relates to a kind of high water-resisting photovoltaic module and its preparation method, belong to solar photovoltaic technical field.The module includes glass cover plate, upper layer encapsulation adhesive film, cell string, lower layer encapsulation adhesive film and back sheet, and sealing body is set to four peripheral edges.The upper layer and lower layer encapsulation adhesive film are silicone modified polyolefin encapsulation adhesive film, include polyolefin base resin and reactive silicone or silane modifier;The edge sealing body is formed by two-component addition curing type silicone rubber.After laminating, adhesive film edge overflow part is rich in silicone / silane component, and two-component silicone rubber is formed with subsequent coating, molecular level integration sealing transition layer from adhesive film to sealant.The preparation method includes: using modified adhesive film lamination;Trimming;Two-component silicone rubber is mixed and coated on the four peripheral edges of module;Resting solidification.The present application realizes the synergistic homogenization of encapsulation and sealing system by material chemical modification, significantly improves the water-resisting performance and long-term reliability of module.

Description

Technical Field

[0001] This invention relates to the field of solar photovoltaic technology, specifically to a photovoltaic module with a high water-resistant structure. In particular, this invention proposes a method for constructing a highly reliable photovoltaic module and its preparation, using a combination of silicone-modified encapsulating film and two-component addition-curing silicone as core materials, through molecular-level interface fusion and rapid deep curing technology, achieving intrinsically integrated sealing from the module's interior to its edges. Background Technology

[0002] Long-term reliability is a key indicator of photovoltaic (PV) module performance, and moisture erosion is one of the main factors leading to performance degradation and even failure. Traditional encapsulation systems primarily rely on ethylene-vinyl acetate copolymer (EVA) or polyolefin elastomer (POE) films for bonding and sealing, and edge protection with one-component silicone sealant. This system has inherent drawbacks: 1. Interface mismatch: The bonding between polyolefin films such as EVA / POE and glass, backsheet and battery cells is physical adsorption and limited chemical bonding. Under long-term humid heat aging, the interface is prone to degradation, forming a channel for moisture intrusion.

[0003] 2. Limitations of edge sealing: Commonly used one-component alcohol-free or ketoxime-free silicone sealants rely on moisture in the air for curing. Curing is slow from the surface inwards, with incomplete deep curing. Furthermore, under shrinkage stress, micro-gaps may form at the interface with the polyolefin film and backing plate. Curing byproducts (such as alcohols and ketoximes) may also have a potential impact on the internal materials.

[0004] 3. Heterogeneous system: The encapsulating film and the edge sealant have very different chemical properties. The interface between the two is a clearly defined weak connection, which cannot form a continuous molecular phase, resulting in a "discontinuity" in the water barrier.

[0005] Therefore, there is an urgent need for an innovative solution that achieves synergy and uniformity between the encapsulation and sealing systems from the perspective of materials chemistry. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of incompatibility between the encapsulation film and the edge sealant interface, incomplete curing of the sealing layer, and insufficient long-term humid heat reliability in the prior art, and to provide a high water-resistant photovoltaic module that achieves integrated sealing from the inside out through material chemical modification.

[0007] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a photovoltaic module with a high water-resistant structure, comprising a stacked glass cover, an upper encapsulating film, a battery string, a lower encapsulating film, and a backsheet, and a sealing body disposed around the perimeter of the module, wherein: At least one of the upper and lower encapsulating films is a silicone-modified polyolefin encapsulating film, wherein the silicone-modified polyolefin encapsulating film comprises a polyolefin matrix resin and a reactive silicone or silane modifier. The sealing body is formed of a two-component addition-cured silicone rubber; The portion of the silicone-modified polyolefin encapsulating film that overflows at the edge of the component forms an integrated sealing transition layer with the two-component addition-curing silicone rubber through physical entanglement and chemical reaction.

[0008] As used in this text, "silicone-modified polyolefin encapsulating film" refers to an encapsulating film made by introducing reactive silicone or silane modifiers into a polyolefin resin matrix through melt blending.

[0009] As used herein, "reactive silicone or silane modifier" refers to an organosilicon compound containing reactive functional groups such as vinyl, epoxy, alkoxy, and amino groups. This compound can migrate to the surface of the encapsulating film under lamination conditions and chemically react with active groups such as hydroxyl groups on the surfaces of the glass, battery cells, and backsheet to form a chemically bonded interface. Preferably, the reactive silicone or silane modifier is selected from at least one of vinyl silicone oil, epoxy silane, vinyltrimethoxysilane, and γ-aminopropyltriethoxysilane, and its addition amount in the encapsulating film is 0.5%-10% of the weight of the polyolefin matrix resin.

[0010] Preferably, the silicone-modified polyolefin encapsulating film also contains uniformly dispersed sheet-like nano-barrier fillers. More preferably, the sheet-like nano-barrier fillers are organically modified montmorillonite or mica powder, and their addition amount is 1-5 wt% of the total weight of the film, so as to construct tortuous water vapor barrier pathways in the film body.

[0011] Preferably, the two-component addition-curing silicone rubber is a hydrosilylation curing system containing a platinum complex catalyst. This silicone rubber is formed by mixing and curing component A (containing vinyl polysiloxane and a platinum catalyst) and component B (containing a hydrogen-containing silicone oil crosslinking agent and an inhibitor) in a specific ratio. Its curing mechanism is a hydrosilylation reaction, which does not produce byproducts and can quickly achieve uniform deep curing from the inside out.

[0012] Preferably, the two-component addition-cured silicone rubber is filled with a reinforcing filler selected from at least one of hydrophobic fumed silica and surface-treated alumina micropowder to enhance its mechanical strength, reduce air permeability, and maintain high elasticity.

[0013] Preferably, the edge sealant is: firstly, a layer of low-modulus, high-elongation two-component silicone is coated on the edge of the laminated component as an inner sealing buffer layer, completely covering the overflow portion of the adhesive film and the edges of the glass and back panel; after it has cured, a layer of high-hardness, high-weather-resistant similar or modified two-component silicone is coated as an outer protective sealing layer.

[0014] Preferably, the polyolefin matrix resin is selected from at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer, and ethylene-α-olefin copolymer.

[0015] Preferably, the back panel is a composite back panel with high barrier properties (such as an aluminum foil structure) or glass.

[0016] Secondly, the present invention provides a method for preparing a photovoltaic module with a high water resistance structure, comprising the following steps: S1: The silicone-modified polyolefin encapsulating film is stacked and laminated to form a laminate with an overflow edge of the encapsulating film; S2: Trim the edges of the laminate; S3: Mix components A and B of the two-component addition-curing silicone rubber and apply it to the edges of the component to cover the excess adhesive film and part of the glass cover and back plate surface. S4: Cures the coated silicone rubber to form an edge seal that is integrated with the encapsulation film.

[0017] Preferably, in step S4, the curing process conditions are: static curing at 20-30℃ for 3-5 hours.

[0018] Silicone-modified polyolefin encapsulating films use ethylene-vinyl acetate copolymers, polyolefin elastomers, or blends thereof as the base resin. Reactive silicone polymers or silane coupling agents containing vinyl or alkoxy groups are introduced as modifiers through melt blending, with the addition amount being 0.5%-10% of the base resin weight. Under lamination conditions (temperature 120-160℃), the silicone component of this modified film migrates to the film surface and reacts with active groups such as hydroxyl groups on the surfaces of glass, the antireflective layer of the battery cell, and the inner layer of the backsheet, forming a strong chemically bonded interface.

[0019] After the silicone-modified polyolefin encapsulating film is laminated into the component, the excess portion at its edges forms a surface layer with chemically continuous properties with the internal encapsulation. This surface layer is rich in silicone / silane components that have migrated to the surface, exhibiting excellent chemical affinity and reaction compatibility with the subsequently coated two-component addition-curing silicone rubber. At the interface between the two, the active components in the silicone rubber can physically entangle with and even partially chemically crosslink with the residual active groups of silicone on the film surface, thereby achieving a seamless molecular-level transition and chemical bonding from the encapsulating film to the edge sealant, improving the weak interface of traditional physical adhesives.

[0020] The beneficial effects of this invention are: (1) This invention uses the chemical synergy of "silicone modified film" and "two-component silicone" to integrate the two independent parts of "encapsulation body" and "edge seal body" in traditional components into a whole that is chemically continuous from the internal interface to the external edge and has no clear weak interface, thereby blocking the water vapor permeation path.

[0021] (2) The silicone-modified film forms a more stable chemical bonding interface with the glass / battery cell / backsheet, and its hydrolysis resistance is better than that of pure physical bonding. The two-component silicone has no by-products and deep curing characteristics, which can ensure the homogeneity, high strength and high elasticity of the edge seal body, and no internal defects.

[0022] (3) Two-component silicone has a fast curing speed and is not dependent on ambient humidity, making it suitable for automated and precise coating and improving production efficiency. Its excellent adhesion to the overflow of the adhesive film can reduce the complex surface treatment steps required for traditional edge sealing.

[0023] (4) The structure of this component has shown significant advantages in passing the stringent PID test, high pressure cooking test, wet freeze cycle test, etc., and is especially suitable for harsh environments such as marine photovoltaic and high humidity areas where long-term weather resistance is required. Attached Figure Description

[0024] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 : A schematic diagram of the structure of the photovoltaic module of the present invention. Detailed Implementation

[0026] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0027] Please refer to the structure of the photovoltaic module. Figure 1 As shown: 1-Glass cover; 2-Upper silicone modified encapsulating film; 3-Battery cell; 4-Lower silicone modified encapsulating film; 5-Backsheet; 6-Two-component addition-curing silicone.

[0028] Example 1

[0029] A method for preparing a high water-resistance photovoltaic module includes the following steps: Materials preparation: Encapsulation film: Custom-made silicone-modified POE film. Using POE resin as the matrix, 3wt% of vinyltrimethoxysilane grafted polymer is added as a modifier, and 2wt% organomontmorillonite is blended together. The film is made into a 0.45mm thick film by casting, which serves as the upper and lower layers of the film.

[0030] Edge sealant: Commercially available two-component addition-curing silicone rubber is used, with a volume ratio of A:B components of 10:1. It has a working time of 30 minutes at 25°C, a surface drying time of less than 2 hours, and a tensile strength of >2MPa and an elongation at break of >300% after complete curing.

[0031] Other: Conventional photovoltaic glass, monocrystalline PERC cells, high water resistance composite backsheet.

[0032] Component fabrication: The standard procedure involves lamination (glass / upper modified film / cell string / lower modified film / backsheet). The lamination process uses a vacuum process followed by pressure curing for 14 minutes at 145°C. After lamination, the film is visibly and evenly overflowing from the module edges.

[0033] After lamination, the components are cooled to below 60°C and then trimmed.

[0034] Using a two-component automated mixing and coating equipment, the mixed two-component silicone is continuously coated along the four edges of the component to form a seal with a size of approximately 3mm (width) × 2mm (height), which fully wets and covers the excess adhesive film and the outer surface of the glass and backplate, which is approximately 1mm wide.

[0035] Allow the edge sealant to cure completely for 4 hours at room temperature (25°C).

[0036] Example 2

[0037] A method for preparing a high water-resistance photovoltaic module includes the following steps: It is basically the same as Example 1, except that: Materials preparation: Encapsulating film: POE resin is used as the matrix, with 5wt% γ-aminopropyltriethoxysilane added as a modifier. No organomontmorillonite is added. The film is made with a thickness of 0.45mm by casting.

[0038] Edge sealant: Same as in Example 1.

[0039] Component fabrication: Lamination process: Same as in Example 1.

[0040] Curing conditions: Allow to cure at room temperature (30°C) for 3 hours.

[0041] The remaining steps are the same as in Example 1.

[0042] Example 3

[0043] A method for preparing a high water-resistance photovoltaic module includes the following steps: It is basically the same as Example 1, except that: Materials preparation: Encapsulation film: The upper layer is a silicone-modified POE film (same as in Example 1), and the lower layer is a conventional POE film (without modifier or filler), both with a thickness of 0.45 mm.

[0044] Edge sealant: adopts a double-layer sealing structure.

[0045] Inner sealant: Low-modulus two-component addition-curing silicone rubber, tensile strength > 1.5 MPa, elongation at break > 400%; Outer sealant: High-hardness two-component addition-curing silicone rubber, Shore hardness > 50A, tensile strength > 3MPa.

[0046] Other: Same as in Example 1.

[0047] Component fabrication: Lamination: Lay the layers in the following order: glass cover plate / upper modified film / battery string / lower conventional POE film / backsheet.

[0048] Lamination: Same as in Example 1.

[0049] Trimming: Same as in Example 1.

[0050] Applying adhesive: First, apply the inner layer of sealant, about 1 mm thick, covering any excess sealant and the edges of the glass and back panel; after curing at 25°C for 2 hours, apply the outer layer of sealant, about 1 mm thick.

[0051] Curing: Continue to cure at room temperature of 25℃ for 3 hours (outer layer curing), for a total curing time of 5 hours.

[0052] The remaining steps are the same as in Example 1.

[0053] Example 4

[0054] A method for preparing a high water-resistance photovoltaic module includes the following steps: It is basically the same as Example 1, except that: Materials preparation: Encapsulation film: POE resin is used as the base material, 0.5 wt% vinyl silicone oil is added as a modifier, and 5 wt% mica powder is blended as a sheet-like nano barrier filler. The film with a thickness of 0.45 mm is made by casting.

[0055] Edge sealant: Same as in Example 1.

[0056] Component fabrication: Lamination process: Same as in Example 1.

[0057] Curing conditions: Allow to cure at room temperature (20°C) for 5 hours.

[0058] The remaining steps are the same as in Example 1.

[0059] Comparative Example 1

[0060] The traditional photovoltaic module manufacturing method differs from that in Example 1 in that: Materials preparation: Encapsulation film: Conventional EVA film (silicone-free modified), 0.45mm thick.

[0061] Edge sealant: Commercially available one-component de-alcoholized silicone sealant, moisture-curing type.

[0062] Other: Same as in Example 1.

[0063] Component fabrication: Lamination: Lay the glass cover / EVA film / battery string / EVA film / backsheet in the following order.

[0064] Lamination: Temperature 145℃, vacuum and pressure curing for 14 minutes.

[0065] Trimming: Trim the edges after cooling.

[0066] Coating: Apply a single-component de-alcoholized silicone sealant, with the same dimensions as in Example 1.

[0067] Curing: Allow to cure at room temperature (25°C) for 48 hours.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is as follows: Materials preparation: Encapsulation film: Same as in Example 1 (silicone modified POE film, containing 3% modifier and 2% montmorillonite).

[0070] Edge sealant: Same as Comparative Example 1 (commercially available one-component dealcoholized silicone sealant).

[0071] Other: Same as in Example 1.

[0072] Component fabrication: Lamination, stacking, and trimming: Same as in Example 1.

[0073] Application and curing: Same as comparative example 1 (single-component silicone, cured at 25°C for 48 hours).

[0074] Performance testing: 1. DH1000 test: Damp heat aging test is carried out in accordance with IEC 61215-MQT 13. The module is placed in a constant temperature and humidity test chamber and run continuously for 1000 hours at 85℃±2℃ and 85%±5%RH. After every 250 hours, the module is taken out and cooled to room temperature. The maximum power of the module is tested using a solar simulator, and the appearance is observed for phenomena such as delamination, bubbles, and cracks.

[0075] 2. Wet leakage current test: The wet leakage current test is performed in accordance with IEC 61215-MQT 15. The component is immersed in an aqueous solution containing surfactant, and the current is measured after the voltage is applied for 2 minutes.

[0076] 3. Observation of interface failure mode: After the DH1000 damp heat aging test is completed, cut the sealing part along the edge of the component and try to peel off the interface between the edge sealant and the overflow part of the film. Observe the failure mode of the peeling surface. If the fracture occurs inside the sealant or film body (cohesive failure), it proves that the interface bonding strength is higher than the material's own strength; if the fracture occurs exactly at the interface between the two (interface failure), it proves that the interface is weakly connected.

[0077] 4. PID Test: The potential-induced degradation test is conducted in accordance with the IEC TS 62804 standard. The module is placed in an environment of 85℃±2℃ and 85%±5%RH. A DC voltage of 1000V (negative terminal grounded) is applied between the output terminal of the module and the grounding frame. After 96 hours, the module is removed and cooled to room temperature to test the maximum power degradation. At the same time, a wet leakage current test is performed. The passing standard is that the power degradation is less than 5% and the wet leakage current test is qualified.

[0078] 5. High-pressure steam test: The high-pressure steam test is carried out in accordance with the JESD22-A102 standard. The component is cut into 10cm×10cm sample pieces and placed in the high-pressure steam tester. It is run continuously for 96 hours under saturated steam conditions of 121℃ and 100%RH. After being taken out, it is naturally cooled to room temperature. The appearance is observed for phenomena such as delamination, bubbling, and discoloration. The electrical integrity is verified by insulation resistance test.

[0079] 6. Wet Freeze Cycling Test: The wet freeze cycle test is conducted in accordance with IEC 61215-MQT 12. The module is placed in an environmental test chamber and cycled 10 times according to the following procedure: maintain at 85℃±2℃ and 85%±5%RH for 20 hours, then cool down to -40℃±2℃ within 4 hours, maintain at -40℃ for 30 minutes, and then heat up to 85℃±2℃ within 4 hours. After the cycle is completed, the maximum power decay of the module is tested and the appearance changes are observed.

[0080]

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A photovoltaic module with a high water-resistant structure, comprising a stacked glass cover, an upper encapsulating film, a cell string, a lower encapsulating film, and a backsheet, and a sealing body disposed around the perimeter of the module, characterized in that: At least one of the upper and lower encapsulating films is a silicone-modified polyolefin encapsulating film, wherein the silicone-modified polyolefin encapsulating film comprises a polyolefin matrix resin and a reactive silicone or silane modifier. The sealing body is formed of a two-component addition-cured silicone rubber; The portion of the silicone-modified polyolefin encapsulating film that overflows at the edge of the component forms an integrated sealing transition layer with the two-component addition-curing silicone rubber through physical entanglement and chemical reaction.

2. The photovoltaic module with a high water resistance structure according to claim 1, characterized in that, The reactive silicone or silane modifier is selected from at least one of vinyl silicone oil, epoxy silane, vinyltrimethoxysilane and γ-aminopropyltriethoxysilane, and its addition amount in the encapsulating film is 0.5%-10% of the weight of the polyolefin matrix resin.

3. The photovoltaic module with a high water-blocking structure according to claim 1, characterized in that, The silicone-modified polyolefin encapsulating film also contains uniformly dispersed sheet-like nano-barrier fillers.

4. The photovoltaic module with a high water-blocking structure according to claim 3, characterized in that, The sheet-like nano barrier filler is organically modified montmorillonite or mica powder, and its addition amount is 1-5 wt% of the total weight of the film.

5. The photovoltaic module with a high water resistance structure according to claim 1, characterized in that, The two-component addition-curing silicone rubber is a hydrosilylation curing system containing a platinum complex catalyst.

6. The photovoltaic module with a high water resistance structure according to claim 1, characterized in that, The two-component addition-curing silicone rubber is filled with reinforcing filler, which is selected from at least one of hydrophobic fumed silica and surface-treated alumina micro powder.

7. The photovoltaic module with a high water-blocking structure according to claim 1, characterized in that, The edge sealant includes an inner layer of buffer sealant and an outer layer of protective sealant, both of which are two-component addition-curing silicone rubbers.

8. The photovoltaic module with a high water resistance structure according to claim 1, characterized in that, The polyolefin matrix resin is selected from at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer, and ethylene-α-olefin copolymer.

9. A method for preparing a photovoltaic module with a high water-blocking structure as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: The silicone-modified polyolefin encapsulating film is stacked and laminated to form a laminate with an overflow edge of the encapsulating film; S2: Trim the edges of the laminate; S3: Mix components A and B of the two-component addition-curing silicone rubber and apply it to the edges of the component to cover the excess adhesive film and part of the glass cover and back plate surface. S4: Cures the coated silicone rubber to form an edge seal that is integrated with the encapsulation film.

10. The preparation method according to claim 9, characterized in that, In step S4, the curing process conditions are: stand curing at 20-30℃ for 3-5 hours.

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