Curved photovoltaic glass packaging manufacturing process

Abstract

This invention discloses a process for encapsulating curved photovoltaic glass, relating to the field of photovoltaic module manufacturing technology. The process includes module stacking, adding a protective layer, lamination encapsulation, and removing the protective layer: After stacking on a curved photovoltaic glass substrate, a protective glass with the same curvature as the substrate is laid on top. The substrate is then placed in a laminator or laminating furnace, preheated to 120 / 125°C for 7 minutes, held at 120 / 125°C and 80 / 90 kPa for 15 / 18 minutes, and cooled and held at 80 / 90 kPa for 7 / 10 minutes. After cooling, the reusable protective glass is removed. This invention achieves uniform pressure transmission by matching the protective glass, significantly reducing the microcrack rate of the solar cells by approximately 80%, power attenuation ≤2%, and yield ≥95%. It effectively solves the problem of uneven pressure during curved lamination, improving power generation efficiency and safety, and is applicable to the production of curved photovoltaic glass for new energy vehicles and buildings.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module manufacturing technology, specifically to the encapsulation process of curved photovoltaic glass. Background Technology

[0002] In recent years, the global energy structure has accelerated its transformation towards green and low-carbon energy, and photovoltaics, as one of the core technologies of clean energy, has seen its application scenarios continuously expand. Curved photovoltaic glass, with its excellent aerodynamic characteristics, flexible shape adaptability, and aesthetic advantages of high integration with buildings and transportation infrastructure, has become an important direction for the high-end and integrated development of the photovoltaic industry. Currently, curved photovoltaic glass is widely used in panoramic sunroofs of new energy vehicles, roof-mounted integrated photovoltaic systems, curved building curtain walls, irregularly shaped photovoltaic components, and curved photovoltaic coverings for vehicles and ships, and market demand continues to grow.

[0003] Traditional planar photovoltaic modules have a mature and stable lamination encapsulation process, ensuring uniform stress on the cells, reliable encapsulation, and stable performance. However, curved photovoltaic glass has a fixed curvature and arc shape, which is fundamentally different from planar structures. Directly using the planar lamination process will lead to a series of difficult-to-solve technical defects. During the lamination encapsulation process, the pressure applied by the laminator cannot be evenly distributed on the curved glass surface. The high points of the arc are subjected to excessive stress, while the low points are subjected to insufficient stress, resulting in local stress concentration. This can easily lead to problems such as microcracks, cracks, and grid breaks in the internal photovoltaic cells.

[0004] Microcracks in solar cells not only directly reduce the photoelectric conversion efficiency of photovoltaic modules, causing output power degradation, but also trigger localized heating, hot spot effects, accelerate the aging of encapsulation materials, and reduce the insulation performance of modules. In severe cases, they can pose safety hazards such as fire and failure. At the same time, microcracks significantly reduce production yield, increase manufacturing costs, shorten product lifespan, and restrict the large-scale and industrialized application of curved photovoltaic glass.

[0005] Currently, there is no mature and unified solution for curved photovoltaic glass encapsulation in the industry. Some companies use flexible buffer materials, segmented pressurization, and customized molds to improve the problem of uneven stress, but the effects are limited and cannot fundamentally solve the problem of microcracks in solar cells caused by uneven pressure transmission. Therefore, developing an encapsulation process that can achieve uniform pressure distribution in the lamination of curved photovoltaic glass, significantly reduce the microcrack rate of solar cells, and improve product yield and reliability has become a core technical problem that urgently needs to be solved in the field of curved photovoltaics. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing curved photovoltaic glass encapsulation processes, such as uneven lamination pressure distribution, easy microcracks in solar cells, decreased power generation efficiency, high hot spot risk, and low product yield. It provides a curved photovoltaic glass encapsulation manufacturing process. By optimizing the lamination structure and segmented temperature and pressure control process, the lamination pressure is uniformly conducted on the curved surface, fundamentally reducing the risk of microcracks in solar cells and improving the power generation efficiency, safety, lifespan, and production yield of curved photovoltaic glass. This meets the high-quality requirements of curved photovoltaic modules in high-end applications such as new energy vehicles and building curtain walls.

[0007] The technical solution of this invention is implemented as follows: the curved photovoltaic glass encapsulation manufacturing process includes the following steps: (1) Module stacking: In a preset order, encapsulation film, photovoltaic cell string, encapsulation film and backsheet material are sequentially laid on the pre-treated curved photovoltaic glass substrate to form a stacked module with complete structure and tight fit. (2) Add a protective layer: A protective glass is laid on top of the stacked assembly. The radius of curvature, surface shape and external dimensions of the protective glass are completely matched with the curved photovoltaic glass substrate. The curvature of the two are consistent, the surfaces are fully attached, the edges are aligned and temporarily fixed by a positioning structure. (3) Lamination and encapsulation: The entire assembly with protective glass is placed in a curved surface special laminator or laminating oven and a three-stage temperature and pressure controlled encapsulation process is performed, which sequentially completes the preheating and vacuuming, high temperature pressure holding and cooling pressure holding processes. (4) Removal of protection: After lamination, the module is cooled to the set temperature, the upper protective glass is removed, and the finished curved photovoltaic glass is obtained after edge trimming and performance testing; The protective glass is made of high-temperature resistant, high-transmittance tempered glass or ultra-clear glass, which can be cleaned and reused.

[0008] Furthermore, during the preheating and vacuuming stages of the lamination encapsulation, a vacuum state is maintained throughout, while the component is preheated to 120~125°C. The duration of this stage is strictly controlled to 7 minutes to ensure that the air inside the laminated component is completely expelled and the encapsulation film is fully softened.

[0009] Furthermore, in the high-temperature pressure holding stage of the lamination encapsulation, the temperature is maintained at 120-125°C, the applied pressure is maintained at 80-90 kPa, and the duration of high-temperature pressure holding is 15-18 minutes, so that the encapsulation film can achieve complete cross-linking and curing.

[0010] Furthermore, in the cooling and pressure holding stage of the lamination encapsulation, the pressure is kept stable at 80-90 kPa without releasing the pressure, and the cooling and pressure holding time is 7-10 minutes, so that the component can be slowly cooled down and stabilized.

[0011] Furthermore, in the component stacking step, the encapsulating film is made of EVA film or POE film. The laying process ensures that the film is flat without wrinkles, bubbles, or misalignment, and that the photovoltaic cell strings are arranged neatly with uniform spacing.

[0012] Furthermore, in the step of adding a protective layer, the protective glass is 5mm thick, tempered, and has high temperature resistance, deformation resistance, and high pressure conduction uniformity, and can be repeatedly used in the production of curved photovoltaic glass encapsulation.

[0013] Furthermore, during the removal of the protective shield, the component cooling temperature must be reduced to below 60°C before the protective glass is removed to avoid component deformation or glass breakage caused by high-temperature removal.

[0014] Furthermore, the curved photovoltaic glass manufactured using the aforementioned process reduces the microcrack rate of the solar cells by approximately 80% compared to traditional processes without a protective layer, controls the power attenuation of the module to within 2%, and eliminates the hot spot effect.

[0015] Furthermore, when using the aforementioned process for mass production, the overall product yield reaches over 95%, the protective glass can be recycled at least 50 times, and the unit product packaging cost is significantly reduced.

[0016] Furthermore, the entire encapsulation process is carried out in a clean and dry environment, with smooth connections between each step of stacking, protection, lamination, and removal. The process parameters are fixed and controllable, and the batch products have excellent consistency. It is suitable for the large-scale manufacturing of curved photovoltaic glass for sunroofs, roofs, and curved facades of new energy vehicles and buildings.

[0017] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: (1) Uniform pressure distribution: By setting up protective glass that perfectly matches the curvature of the substrate, the laminator pressure is uniformly transmitted to the entire curved component surface, eliminating local stress concentration and preventing microcracks in the battery cells from the root.

[0018] (2) Significantly reduced microcrack rate: The microcrack rate of the battery cells is reduced by about 80% compared with the traditional process, which significantly improves the structural integrity and electrical performance stability of the module.

[0019] (3) Stable electrical performance: The power decay of the components is controlled within 2%, ensuring efficient power generation and stable and reliable output power.

[0020] (4) Enhanced safety: Effectively avoids safety hazards such as hot spot effect and local overheating, and improves the safety and durability of the components.

[0021] (5) High production yield: The product yield can reach over 95%, reducing scrap rate and manufacturing costs, making it suitable for mass industrial production.

[0022] (6) Reusable protective glass: Reusable protective glass is used, which does not increase the cost of additional materials and is environmentally friendly and economical.

[0023] (7) Stable and controllable process: The three-stage precise temperature and pressure control process has clear parameters and standardized procedures, ensuring batch consistency and product stability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the overall process of the present invention; Figure 2 This is a detailed flowchart of the lamination and encapsulation process of the present invention; Figure 3 This is a detailed flowchart of the component stacking of the present invention. Detailed Implementation

[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0027] Example 1 A process for encapsulating curved photovoltaic glass, the specific steps of which are as follows: 1. Pretreatment: Select curved photovoltaic glass with radius of curvature R as the substrate, and clean it with ultrasonic cleaning, deionized water rinsing, and hot air drying before use; select 5mm thick tempered protective glass with shape, curvature, and size completely consistent with the substrate, and clean and dry it before use.

[0028] Module stacking: On a curved photovoltaic glass substrate, the first layer of EVA encapsulation film, the neatly arranged photovoltaic cell strings, the second layer of EVA encapsulation film, and the composite backsheet material are sequentially laid to form a tightly bonded stacked module, ensuring no bubbles and no wrinkles.

[0029] Add a protective layer: Precisely cover the top of the laminated components with protective glass to ensure full fit and edge alignment, and use high-temperature resistant positioning tape to fix it to prevent displacement.

[0030] Lamination and encapsulation: The entire assembly is placed in a specialized curved surface laminator, and three process parameters are set: (1) Preheating and vacuuming: 7 minutes, heat up to 120℃; (2) High temperature pressure holding: 120℃, 85kPa, for 16 minutes; (3) Cooling and holding pressure: 85 kPa, for 8 minutes.

[0031] The startup program completes the encapsulation process.

[0032] Remove the protective glass: Cool the components to 55°C, remove and remove the protective glass, trim the edges, clean, and perform electrical performance testing.

[0033] Testing revealed that the microcrack rate of the solar cells was reduced by 80%, the power degradation was 1.8%, there were no hot spots, and the yield rate was 96%.

[0034] Example 2 A process for encapsulating curved photovoltaic glass, the specific steps of which are as follows: 1. Pretreatment: Select a curved photovoltaic glass substrate with a radius of curvature of R, clean and dry it for later use; select 5mm thick ultra-clear protective glass with a curvature that perfectly matches the substrate, clean and dry it for later use.

[0035] Module stacking: POE encapsulation film, photovoltaic cell string, POE film, and photovoltaic backsheet are sequentially laid on the substrate to ensure that each layer is flat and adhered.

[0036] Add a protective layer: Protective glass covers the top layer, is precisely positioned, and is fixed with high-temperature resistant clamps.

[0037] Lamination and encapsulation: Place in a curved surface laminator, parameter settings: (1) Preheating and vacuuming: 7 minutes, heating up to 123℃; (2) High temperature pressure holding: 123℃, 80kPa, for 15 minutes; (3) Cooling and holding pressure: 80 kPa, for 7 minutes.

[0038] Complete lamination and encapsulation.

[0039] Remove protection: Cool to below 50°C, remove the protective glass, and perform repairs and inspection.

[0040] Testing revealed that the microcrack rate was reduced by 80%, power attenuation was 1.9%, there were no hot spots, and the yield was 95.5%.

[0041] Example 3 A process for encapsulating curved photovoltaic glass, the specific steps of which are as follows: 1. Pretreatment: The curved photovoltaic glass substrate with a radius of curvature R is cleaned and dried for later use; the 5mm tempered protective glass with the same curvature as the substrate is cleaned for later use.

[0042] Module stacking: EVA film, battery cell string, EVA film, and weather-resistant backsheet are laid in sequence to form a stable stacked structure.

[0043] Add a protective layer: cover and position with protective glass, and secure with tape.

[0044] Lamination and encapsulation: Place in a lamination oven, parameter settings: (1) Preheating and vacuuming: 7 minutes, heating up to 125℃; (2) High temperature pressure holding: 125℃, 90kPa, for 18 minutes; (3) Cooling and holding pressure: 90 kPa, for 10 minutes.

[0045] Complete packaging.

[0046] Remove protection: Cool to below 60°C, remove the protective glass, and perform repairs and testing.

[0047] Testing revealed that the microcrack rate was reduced by 80%, power attenuation was 1.7%, there were no hot spots, and the yield was 96.5%.

[0048] The above three embodiments demonstrate that the process of the present invention is stable and reliable, and all performance indicators meet the design requirements, making it suitable for industrial mass production.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A process for manufacturing curved photovoltaic glass encapsulation, characterized in that, Includes the following steps: (1) Module stacking: In a preset order, encapsulation film, photovoltaic cell string, encapsulation film and backsheet material are sequentially laid on the pre-treated curved photovoltaic glass substrate to form a stacked module with complete structure and tight fit. (2) Add a protective layer: A protective glass is laid on top of the stacked assembly. The radius of curvature, surface shape and external dimensions of the protective glass are completely matched with the curved photovoltaic glass substrate. The curvature of the two are consistent, the surfaces are fully attached, the edges are aligned and temporarily fixed by a positioning structure. (3) Lamination and encapsulation: The entire assembly with protective glass is placed in a curved surface special laminator or laminating oven and a three-stage temperature and pressure controlled encapsulation process is performed, which sequentially completes the preheating and vacuuming, high temperature pressure holding and cooling pressure holding processes. (4) Removal of protection: After lamination, the module is cooled to the set temperature, the upper protective glass is removed, and the finished curved photovoltaic glass is obtained after edge trimming and performance testing; The protective glass is made of high-temperature resistant, high-transmittance tempered glass or ultra-clear glass, which can be cleaned and reused.

2. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: During the preheating and vacuuming stage of the lamination encapsulation, a vacuum state is maintained throughout, and the component is preheated to 120~125℃. The duration of this stage is strictly controlled to 7 minutes to ensure that the air inside the laminated component is completely expelled and the encapsulation film is fully softened.

3. The curved photovoltaic glass encapsulation manufacturing process according to claim 2, characterized in that: In the high-temperature pressure holding stage of the lamination encapsulation, the temperature is maintained at 120-125°C, the applied pressure is maintained at 80-90 kPa, and the high-temperature pressure holding time is 15-18 minutes, so that the encapsulation film can achieve complete cross-linking and curing.

4. The curved photovoltaic glass encapsulation manufacturing process according to claim 3, characterized in that: During the cooling and pressure holding stage of the lamination encapsulation, the pressure is kept stable at 80-90 kPa without releasing the pressure. The cooling and pressure holding time is 7-10 minutes, allowing the component to cool down slowly and stabilize.

5. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: In the component stacking process, the encapsulating film is made of EVA film or POE film. The laying process ensures that the film is flat, without wrinkles, bubbles, or misalignment, and that the photovoltaic cell strings are arranged neatly with uniform spacing.

6. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: In the step of adding a protective layer, the protective glass is 5mm thick, tempered, and has high temperature resistance, deformation resistance, high pressure conduction uniformity, and can be repeatedly used in the production of curved photovoltaic glass encapsulation.

7. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: During the removal of the protective shield, the component cooling temperature must be reduced to below 60°C before the protective glass is removed to avoid component deformation or glass breakage caused by high-temperature removal.

8. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: The curved photovoltaic glass manufactured using the aforementioned process has a microcrack rate of approximately 80% lower than that of traditional processes without a protective layer, and the power attenuation of the module is controlled within 2%, with no hot spot effect generated.

9. The curved photovoltaic glass encapsulation manufacturing process according to claim 1, characterized in that: When mass production is carried out using the aforementioned process, the overall product yield reaches over 95%, the protective glass can be recycled at least 50 times, and the unit product packaging cost is significantly reduced.

10. The curved photovoltaic glass encapsulation manufacturing process according to any one of claims 1 to 9, characterized in that: The entire encapsulation process is carried out in a clean and dry environment. The steps of stacking, protection, lamination, and removal are smoothly connected. The process parameters are fixed and controllable, and the batch products have excellent consistency. It is suitable for the large-scale manufacturing of curved photovoltaic glass for sunroofs, roofs, and curved facades of new energy vehicles and buildings.

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