High-performance organic silicon packaging adhesive for photovoltaic module

Abstract

The invention relates to a high-performance organic silicon packaging adhesive for a photovoltaic module, the packaging adhesive is an organic high-molecular compound taking a silicon-oxygen bond as a main chain, and a colloidal elastomer is formed after the packaging adhesive is cured; the working temperature range of the packaging adhesive is-55 DEG C to 250 DEG C, the light transmittance of the packaging adhesive in a visible light range is not lower than 92%, and after the packaging adhesive is aged for 1000 hours under the double-85 test conditions of 85 DEG C and 85% relative humidity, the light transmittance retention rate is larger than 95%; the packaging adhesive is prepared from a monomer mixture containing dimethyl dichlorosilane and methyl trichlorosilane through high-temperature reaction, hydrolysis and condensation processes under the action of a composite catalytic system of copper and various high polymer materials, and finally a network polymer with linear and cross-linked structures is formed. The core purpose of the invention is to provide a revolutionary photovoltaic packaging material which is high in light transmittance, extremely stable in chemical property, capable of greatly improving the reliability, the service life and the power generation efficiency of a component, and environment-friendly and recoverable.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic materials technology, and in particular to high-performance silicone encapsulants for photovoltaic modules. Background Technology

[0002] Ethylene-vinyl acetate copolymer (EVA) is the most traditional and mainstream encapsulation material for photovoltaic (PV) module lamination. However, EVA has revealed many inherent defects during long-term outdoor use. First, EVA is prone to hydrolysis and photoaging in humid, hot, and ultraviolet environments, decomposing to produce acetic acid. Acetic acid corrodes the silver grid lines and antireflective coating of the solar cells, leading to continuous power degradation of the module, the so-called "PID effect" and yellowing due to aging. Second, EVA is solid after curing, and its coefficient of thermal expansion is mismatched with that of glass and solar cells. This generates continuous mechanical stress during day-night and seasonal temperature cycles, which can easily cause microcracks in the solar cells. Third, EVA modules are difficult to recycle after retirement, and separating the solar cells from EVA is difficult, resulting in significant environmental pollution. To address these issues, the industry has developed polyolefin encapsulation films such as POE and EPE. POE has excellent water vapor barrier properties and anti-PID performance, but its adhesion, weather resistance, and the complexity of co-extrusion with EVA remain challenges. Furthermore, both EVA and POE typically have an upper operating temperature limit of 120°C. For next-generation TOPCon batteries operating at higher temperatures or using thinner silicon wafers and lower silver paste consumption, their long-term reliability faces severe tests. TOPCon batteries place even more stringent requirements on the high-temperature resistance, low corrosion resistance, and stress buffering capacity of encapsulation materials. Therefore, developing a new type of encapsulation material that combines ultra-high weather resistance, excellent corrosion resistance, superior stress buffering performance, and compatibility with future high-efficiency battery technology development has become a key link in promoting technological progress in the photovoltaic industry. Summary of the Invention

[0003] The problem solved by this invention is to provide a high-performance silicone encapsulant for photovoltaic modules. Its core objective is to provide a revolutionary photovoltaic encapsulation material with high light transmittance, extremely stable chemical properties, which can significantly improve the reliability, lifespan and power generation efficiency of modules, while also taking into account environmental protection and recyclability.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-performance silicone encapsulant for photovoltaic modules, wherein the encapsulant is an organic polymer compound with silicon-oxygen bonds as the main chain, which forms a gel-like elastomer after curing; the working temperature range of the encapsulant is -55℃ to 250℃, its transmittance in the visible light range is not less than 92%, and after aging for 1000 hours under the double 85 test conditions of 85℃ and 85% relative humidity, its transmittance retention rate is greater than 95%.

[0005] Preferably, the encapsulating adhesive is prepared by a monomer mixture containing dimethyldichlorosilane and methyltrichlorosilane through high-temperature reaction, hydrolysis and condensation processes under the action of a composite catalytic system of copper and various polymer materials, ultimately forming a network polymer with both linear and cross-linked structures.

[0006] Preferably, the energy consumption required by the encapsulating adhesive in the photovoltaic module lamination process is less than one-tenth of the energy consumption of traditional EVA encapsulating adhesive film lamination. The photovoltaic module includes an upper glass layer, GNJ encapsulating adhesive, TOPCon cell strings, GNJ encapsulating adhesive, and a transparent backsheet. GNJ encapsulating adhesive is installed on the bottom outer wall of the upper glass layer. TOPCon cell strings are distributed and installed on the bottom outer wall of the GNJ encapsulating adhesive. GNJ encapsulating adhesive is installed on the bottom outer wall of the TOPCon cell strings. A transparent backsheet is installed on the bottom outer wall of the GNJ encapsulating adhesive.

[0007] Preferably, the encapsulating adhesive is a chemically inert material that does not decompose to produce acidic substances within a temperature range of 80°C to 250°C and under long-term ultraviolet irradiation, thus effectively preventing corrosion of the silver grid electrode and semiconductor layer of the battery cell.

[0008] Preferably, the TOPCon photovoltaic module encapsulated with the aforementioned encapsulating adhesive has a first-year power degradation rate of no more than 0.22% and a cumulative power degradation rate of no more than 13% over 50 years.

[0009] Preferably, the gel-like elastic properties of the encapsulating adhesive can absorb and buffer the thermomechanical stress generated by the photovoltaic module during day-night temperature difference cycles, reducing the risk of microcracks in the cells and breakage of the interconnect strips.

[0010] Preferably, the crystalline silicon photovoltaic module encapsulated with the aforementioned encapsulating adhesive has an average photoelectric conversion efficiency that is 1.5% to 2.0% higher than that of the same module encapsulated with traditional EVA film.

[0011] Preferably, the encapsulating adhesive is suitable for bifacial photovoltaic modules with a glass-glass structure and can meet the high moisture barrier requirements of TOPCon cells for encapsulating materials.

[0012] Preferably, at the end of its life cycle, the solar cells of a photovoltaic module using the encapsulating adhesive can be completely separated from the adhesive by physical means, facilitating recycling and reuse.

[0013] Preferably, the encapsulating adhesive enables the photovoltaic module casing to have Class A fire resistance and supports the creation of complex curved surfaces that are not planar.

[0014] The beneficial effects of this invention are: ultra-long lifespan and ultra-high reliability: the inorganic silicon-oxygen backbone gives the material excellent stability, a wide operating temperature range, and strong weather resistance. The expected service life of the module can reach 50 years, with an extremely low attenuation rate, and a lifespan that is 2-3 times that of traditional modules. Ultimate power generation gain: High light transmittance and permanent anti-yellowing properties ensure that the module maintains high light transmittance throughout its entire life cycle, directly improving the module's power output and conversion efficiency; Intrinsic corrosion resistance and microcrack resistance: Chemical inertness eliminates cell corrosion, and gel-like elasticity effectively buffers thermal stress, providing dual protection for the long-term safety of high-efficiency and fragile battery structures such as TOPCon. Green manufacturing and circular economy: production energy consumption is significantly reduced, components are easy to recycle, and solar cells can be reused, making it highly environmentally friendly; With broad application prospects, its superior performance perfectly meets the stringent requirements of next-generation high-efficiency battery technologies such as TOPCon and HJT for encapsulation materials. It is expected to become the mainstream encapsulation solution for high-performance modules within the next three years, forming a market pattern that complements the existing POE / PVB / EVA films. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the layered structure of the high-performance silicone encapsulant of the present invention applied to a typical photovoltaic module; Figure 2 A comparison chart of performance parameters between a traditional EVA encapsulation component and the GNJ adhesive encapsulation component of this invention; Figure 3 This is a process diagram for preparing the GNJ adhesive of the present invention.

[0016] Legend: 1. Top glass; 2. GNJ encapsulating adhesive; 3. TOPCon battery string; 4. GNJ encapsulating adhesive; 5. Transparent backplate. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 See Figure 3This is a high-performance silicone encapsulant for photovoltaic modules. The encapsulant is an organic polymer compound with silicon-oxygen bonds as the main chain, which forms a gel-like elastomer after curing. The working temperature range of the encapsulant is -55℃ to 250℃, and its transmittance in the visible light range is not less than 92%. After aging for 1000 hours under the double 85 test conditions of 85℃ and 85% relative humidity, its transmittance retention rate is greater than 95%. The encapsulating adhesive is prepared by a mixture of monomers containing dimethyldichlorosilane and methyltrichlorosilane through high-temperature reaction, hydrolysis and condensation processes under the action of a composite catalytic system of copper and various polymer materials, ultimately forming a network polymer with both linear and cross-linked structures.

[0019] Working principle: First, high-purity silica powder and chloromethane are mixed in a reactor. Under the action of a composite catalytic system composed of a copper-based catalyst and four specific polymer co-catalysts, a fluidized bed reaction is carried out at 280℃~320℃ to generate mixed chlorosilane monomers. The main component is dimethyldichlorosilane, and it contains a certain proportion of methyltrichlorosilane for crosslinking. Next, the mixed chlorosilane monomers were purified by distillation; the purified monomers were then hydrolyzed under strictly controlled pH and temperature conditions to produce the corresponding silanols. Finally, silanol undergoes a polycondensation reaction under the action of a catalyst. By precisely controlling the reaction temperature, time, and material ratio, linear polycondensation and cross-linking reactions are carried out in synergy, ultimately synthesizing a colorless and transparent viscous liquid, namely GNJ organosilicon encapsulant. This liquid can be completely cured to form an elastomer during the subsequent component lamination process under heating and catalyst activation.

[0020] Example 2 See Figure 1 The energy consumption required by the encapsulant in the photovoltaic module lamination process is less than one-tenth of that of the traditional EVA encapsulant film lamination process. The photovoltaic module includes an upper glass 1, GNJ encapsulant 2, TOPCon cell string 3, GNJ encapsulant 4 and transparent back sheet 5. GNJ encapsulant 2 is installed on the bottom outer wall of the upper glass 1. TOPCon cell string 3 is distributed and installed on the bottom outer wall of GNJ encapsulant 2. GNJ encapsulant 4 is installed on the bottom outer wall of TOPCon cell string 3. Transparent back sheet 5 is installed on the bottom outer wall of GNJ encapsulant 4. The encapsulating adhesive is a chemically inert material that does not decompose and produce acidic substances within a temperature range of 80℃ to 250℃ and under long-term ultraviolet radiation, effectively preventing corrosion of the silver grid electrode and semiconductor layer of the solar cell. TOPCon photovoltaic modules encapsulated with encapsulant have a first-year power degradation rate of no more than 0.22% and a cumulative power degradation rate of no more than 13% over 50 years. The gel-like elastic properties of the encapsulating adhesive can absorb and buffer the thermomechanical stress generated by the photovoltaic module during the day-night temperature difference cycle, reducing the risk of microcracks in the cells and breakage of the interconnect strips; The average photoelectric conversion efficiency of crystalline silicon photovoltaic modules using encapsulation adhesive is between 1.5% and 2.0% higher than that of the same type of modules using traditional EVA film encapsulation. The encapsulating adhesive is suitable for bifacial photovoltaic modules with glass-glass structures and can meet the high water vapor barrier requirements of TOPCon cells for encapsulating materials. At the end of their life cycle, the solar cells of photovoltaic modules using encapsulating adhesive can be completely separated from the adhesive by physical means, making them easy to recycle and reuse. The encapsulating adhesive enables the photovoltaic module casing to have Class A fire resistance and allows the photovoltaic module to be made into a complex curved shape that is not planar.

[0021] Using a conventional lamination process, the stacking sequence is as follows: upper glass 1, GNJ encapsulant 2, TOPCon battery string 3, GNJ encapsulant 4, and transparent backplate 5; The above-mentioned laminates are placed in a laminator. Due to the excellent flowability and reactivity of GNJ adhesive, its lamination process window is wider. The lamination temperature used in this embodiment is 150°C and the lamination time is 12 minutes, which is far lower than the typical requirement of 145-150°C / 15-20 minutes for EVA, resulting in a significant reduction in energy consumption. After lamination, a photovoltaic module with a dense structure, no bubbles, and a transparent appearance is obtained.

[0022] Comparison and performance testing: The TOPCon modules encapsulated with the GNJ adhesive of this invention were compared with the TOPCon modules of the same batch encapsulated with conventional EVA film. Light transmittance and aging tests: such as Figure 2 As shown, in the initial state, the light transmittance of the GNJ adhesive module was 93.5%, while that of the EVA module was 91.2%. After 1000 hours of double 85 aging, the light transmittance retention of the GNJ adhesive module reached 96.5%, while that of the EVA module dropped to 88.1% due to yellowing. Electrical performance degradation: Maximum power tests show that the simulated degradation value of GNJ adhesive modules in the first year is 0.20%, and the cumulative degradation over 50 years is expected to be 12.8%; while the degradation of EVA modules in the first year is 0.65%, and the cumulative degradation over 25 years is expected to exceed 20%. Mechanical stress testing: such as Figure 3 As shown, after 600 thermal cycles (-40℃~85℃), the EVA module EL image showed obvious microcracks and broken grids, while the GNJ adhesive module EL image was uniform and had no obvious defects. Corrosion resistance: After testing at 85℃ / 85%RH / 1000h, obvious corrosion was observed on the grid lines of the cells inside the EVA module, while the grid lines of the cells in the GNJ glue module remained intact. The above test data fully demonstrates the significant advantages of the high-performance silicone encapsulant provided by this invention in improving the efficiency, reliability, and lifespan of photovoltaic modules.

[0023] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-performance silicone encapsulant for photovoltaic modules, characterized in that, The encapsulating adhesive is an organic polymer compound with silicon-oxygen bonds as the main chain, which forms a gel-like elastomer after curing. The working temperature range of the encapsulating adhesive is -55℃ to 250℃, and its transmittance in the visible light range is not less than 92%. After aging for 1000 hours under the double 85 test conditions of 85℃ and 85% relative humidity, its transmittance retention rate is greater than 95%.

2. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The encapsulating adhesive is prepared by a mixture of monomers containing dimethyldichlorosilane and methyltrichlorosilane through high-temperature reaction, hydrolysis and condensation processes under the action of a composite catalytic system of copper and various polymer materials, ultimately forming a network polymer with both linear and cross-linked structures.

3. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The energy consumption required by the encapsulant in the photovoltaic module lamination process is less than one-tenth of that of traditional EVA encapsulant film lamination. The photovoltaic module includes an upper glass (1), GNJ encapsulant (2), TOPCon cell string (3), GNJ encapsulant (4), and a transparent backplate (5). GNJ encapsulant (2) is installed on the bottom outer wall of the upper glass (1). TOPCon cell string (3) is distributed and installed on the bottom outer wall of the GNJ encapsulant (2). GNJ encapsulant (4) is installed on the bottom outer wall of the TOPCon cell string (3). A transparent backplate (5) is installed on the bottom outer wall of the GNJ encapsulant (4).

4. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The encapsulating adhesive is a chemically inert material that does not decompose to produce acidic substances within a temperature range of 80°C to 250°C or under long-term ultraviolet radiation, effectively preventing corrosion of the silver grid electrode and semiconductor layer of the battery cell.

5. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The TOPCon photovoltaic modules encapsulated with the aforementioned encapsulation adhesive have a power degradation rate of no more than 0.22% in the first year and a cumulative power degradation rate of no more than 13% over 50 years.

6. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The adhesive's gel-like elastic properties can absorb and buffer the thermomechanical stress generated by the photovoltaic module during day-night temperature difference cycles, reducing the risk of microcracks in the cells and breakage of the interconnect strips.

7. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The average photoelectric conversion efficiency of the crystalline silicon photovoltaic module encapsulated with the aforementioned encapsulant is between 1.5% and 2.0% higher than that of the same module encapsulated with traditional EVA film.

8. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The encapsulating adhesive is suitable for bifacial photovoltaic modules with a glass-glass structure and can meet the high water vapor barrier requirements of TOPCon cells for encapsulating materials.

9. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, At the end of their life cycle, the solar cells of photovoltaic modules using the aforementioned encapsulating adhesive can be physically separated from the adhesive, facilitating recycling and reuse.

10. The high-performance silicone encapsulant for photovoltaic modules according to claim 1, characterized in that, The encapsulating adhesive enables the photovoltaic module casing to have Class A fire resistance and supports the creation of complex curved surfaces that are not planar.

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