Preparation method of coated and perforated photovoltaic backboard glass

Abstract

The invention provides a preparation method of coated and punched photovoltaic backboard glass. The preparation method comprises the following preparation steps: S1, substrate preparation; S2, substrate preparation pretreatment; S3, bottom layer film preparation; the method has the advantages of being simple in step, convenient to implement, safe in punching process, high in punching speed, high in efficiency, good in economic benefit, low in production cost and the like, the influence of mechanical impact on the yield of the photovoltaic glass is avoided, the machining precision and quality stability of the photovoltaic backboard glass are improved, and the production efficiency and the automation level can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic glass production, and in particular to a method for preparing coated and perforated photovoltaic back panel glass. Background Art

[0002] Driven by the installed capacity demand in my country and the overseas market, the photovoltaic industry is showing a trend of stable growth. In particular, double-glass photovoltaic modules, with excellent performance such as high power generation, strong resistance to PID (potential induced degradation), and high reliability, are an important development direction for crystalline silicon photovoltaic modules. With the widespread application of N-type battery (N-Topcon, BC, etc.) technology, double-glass modules have become mainstream, and their application scenarios are spread across large ground power stations, distributed power stations on building roofs, tidal flats and islands, and offshore photovoltaic floating power stations.

[0003] With the accelerated development of my country's offshore photovoltaic industry, the application of double-glass photovoltaic modules in special environments such as the ocean has become a major trend. At present, the power generation efficiency of the back of double-glass modules accounts for about 10% of the total. Since the back glass of double-glass photovoltaic modules is a common silk-screen punched or only punched product, the glass velvet surface exposed to the environment has not been treated in any way and it is difficult to resist the erosion and damage of the harsh environment such as high temperature, high humidity, and high salt fog at sea for a long time, which seriously affects the light transmittance performance of the back glass and the power generation efficiency of the double-glass module back. Improving the light transmittance of photovoltaic back glass has become a new demand for increasing the power of modules at the module end. The coating on the surface of the back glass is to improve the light transmittance of the module back and the weather resistance of the overall module in special environments such as the ocean, so as to ensure the power generation efficiency of the module.

[0004] When coating and drilling holes on the velvet surface of the photovoltaic backplane glass, you can choose to coat first and then drill holes, or you can choose to drill holes first and then coat. Considering the method of drilling holes first and then coating, after drilling holes, the coating rubber roller will contact the holes on the glass surface, leaving three hole marks on the subsequent film surface, which will become a defect on the product.

[0005] To avoid this problem, a technical solution of coating first and then drilling is adopted. However, during the laser drilling process, the uneven surface of the glass will cause diffuse reflection of the laser beam, which will reduce the energy concentration of the laser and thus affect the quality and efficiency of the drilling. In the original backplane glass drilling process, water is usually sprayed on the glass surface to solve the problem of the uneven glass surface. However, when it is applied to the coated surface, it will damage the film surface and reduce the light transmittance of the film surface, thereby affecting the photoelectric conversion efficiency of the photovoltaic module.

[0006] Therefore, a matching liquid for laser drilling of coated glass is provided in the preparation process to replace water and is applied to the surface of the coated glass. The matching liquid has the properties of not damaging the film layer, not easy to burn, and completely volatilizing after tempering, so as to solve the diffuse reflection of the laser beam caused by the uneven surface of the glass during the drilling process, and ensure the drilling accuracy and film surface quality. Summary of the invention

[0007] The present invention provides a method for preparing a coated and perforated photovoltaic back panel glass in order to overcome the deficiencies in the prior art.

[0008] This application provides the following technical solutions: A method for preparing a coated and perforated photovoltaic backplane glass, characterized in that it comprises the following preparation steps: S1: taking ultra-white rolled glass as a glass substrate, and grinding and cleaning the glass substrate; S2: drying and preheating the glass substrate; S3: Use a coating machine to coat the base film in a constant temperature and humidity coating workshop with a temperature of 20°C to 28°C and a humidity of 30% to 45%, and then perform high temperature curing of the base film; S4: When the temperature of the glass substrate is cooled to ≤40°C, a surface film is coated on the bottom film, and then the surface film is cured at high temperature; S5: Send the double-coated glass substrate to the laser drilling process. The laser drilling process includes lowering the retractable laser protection cover through the lifting mechanism inside the laser probe assembly of the drilling machine. The liquid spraying device sprays the laser drilling matching liquid on the surface of the coated glass in the laser protection cover. The matching liquid is a mixture of propylene glycol dicaproate (20%-30%), carbon tetrachloride (3%-10%), diethylene glycol butyl ether acetate (10%-20%), bromonaphthalene (25%-35%), and glycerol (15%-25%). The laser probe starts working, emitting a circular laser beam, which cuts off a circular glass piece with a diameter of 10-15mm. A recovery device for the punched and cut glass pieces and matching liquid is arranged under the glass. The recovery device comprises a recovery tank body. The recovery tank body is provided with pipelines corresponding to the laser protection cover. A plurality of filter layers are arranged in the middle of the recovery tank body. A recovery pipe is connected to the bottom of the recovery tank body.

[0009] Step S6, tempering treatment, drying and preheating the coated and perforated glass substrate at 200-250° C. before tempering, and tempering the preheated glass substrate to obtain a coated and perforated photovoltaic backplane glass.

[0010] On the basis of the above technical solutions, there can be the following further technical solutions: In the drying and preheating treatment in S2, the drying and preheating temperature is controlled between 100° C. and 200° C., and the preheating time is controlled between 15 and 30 seconds.

[0011] The recovery tank body is connected with an exhaust pipe to form a micro-negative pressure environment inside the recovery tank body.

[0012] The filtering layer comprises an upper grid, a filtering core layer and a lower grid which are sequentially distributed from top to bottom.

[0013] The plurality of filter layers are horizontally and parallelly distributed from top to bottom, and the filter apertures decrease in sequence from top to bottom.

[0014] A sealing ring is arranged at the opening end of the laser protection cover.

[0015] Advantages of the invention: The present invention provides a method with simple steps, convenient implementation, safe drilling process, fast drilling speed, high efficiency, good economic benefits, low production cost and the like. It avoids the influence of mechanical impact on the yield rate of photovoltaic glass, improves the processing accuracy and quality stability of photovoltaic backplane glass, and can also significantly improve production efficiency and automation level. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the laser probe assembly and the recovery device of the punching machine in the present invention; Figure 2 yes Figure 1 A-direction enlarged view; Figure 3 yes Figure 1 B-direction enlarged view. DETAILED DESCRIPTION

[0017] like Figure 1-3 As shown, a method for preparing a coated and perforated photovoltaic back panel glass comprises the following preparation steps: S1: Substrate preparation, take ultra-white rolled glass as glass substrate 1, use edge grinding machine to grind the glass edge into arc edge, and chamfer the four corners into 45 degrees. Then use cleaning machine to clean the edged glass substrate 1, remove the glass powder after edge grinding, and the dirt attached to the glass substrate itself. The cleaning machine uses pure water to clean the glass substrate, and blows the water mist on the glass substrate with a wind knife. Before coating, the glass substrate must be clean and free of static electricity.

[0018] S2: Substrate preparation pretreatment, drying and preheating the glass substrate. The surface of the cleaned glass substrate needs to be kept dry, and hot air drying is used to remove residual moisture.

[0019] The cleaned and dried substrate is passed through the preheating zone and dried and preheated in a preheating furnace to remove surface moisture and prevent the formation of water stains and stains. The drying preheating temperature is controlled at 120°C and the preheating time is controlled at 20s. During the preheating process, the hot air circulation system will continuously blow hot air into the oven to ensure that the substrate is heated evenly.

[0020] S3: Preparation of the bottom film, using a coating machine to coat the bottom film in a constant temperature and humidity coating workshop with a temperature of 25°C and a humidity of 40%, the coating machine speed is set to 9.5m / min, and then high temperature curing of the bottom film 2 is performed. The coating liquid uses the CG-108D series ultra-high weather-resistant AR coating liquid bottom film liquid of "Chenguang (Changzhou) New Material Technology Co., Ltd."

[0021] The coated glass substrate enters the high-temperature curing furnace. The furnace wire is heated at 145℃ to quickly heat the glass to the required temperature, ensuring that the temperature taken away by the glass can be quickly replenished. This curing method can prevent the glass substrate from being poorly bonded to the film layer and the glass substrate due to the rapid drop in temperature and high surface humidity after the first coating and curing, resulting in differences in the surface appearance of the glass substrate and reduced transmittance. The bottom film thickness is 80nm and the refractive index is 1.4.

[0022] S4: Preparation of the surface film. When the temperature of the glass substrate is cooled to ≤40°C, the surface film is coated on the bottom film, and then the surface film is cured at high temperature 3. The speed of the coating machine is set to 10.4m / min, and the coating liquid uses the CG-108D series ultra-high weather-resistant AR coating liquid of "Chenguang (Changzhou) New Material Technology Co., Ltd.". The surface film is cured after coating.

[0023] The curing process uses a furnace wire to heat at 110℃ to firmly bond the surface film 3 to the bottom film 2 and the glass substrate. The cooling machine is used to cool down after curing. The glass substrate directly enters the air cooling section after leaving the curing furnace, and the surface temperature of the glass drops to ≤30℃. The thickness of the surface film is 115nm and the refractive index is 1.3.

[0024] The beneficial effect of using double-layer coating lies in the combination of dense bottom film structure and porous silica surface film structure. By adjusting the thickness of the bottom film and the surface film, the reflectivity of sunlight is further reduced and the light transmittance in the infrared band is increased, thereby obtaining a higher sunlight transmittance than single-layer coated glass. It effectively resists the erosion of the glass body caused by environmental factors, prolongs the service life of photovoltaic modules, optimizes the optical properties of the glass surface, and improves light transmittance.

[0025] S5: Laser drilling, sending the double-layer coated glass substrate to the laser drilling process, the laser drilling process includes lowering a set of retractable laser protection covers 6 through the lifting mechanism 9 inside the existing punching machine laser probe assembly, and covering the glass substrate to be punched. A sealing ring 6a is installed at the open end of each laser protection cover 6, so that a watertight environment is formed inside the laser protection cover 6.

[0026] Each laser protective cover 6 is connected with a liquid spraying pipe 7 of a liquid spraying device (not shown) and a laser probe 4. The liquid spraying pipe sprays laser drilling matching liquid 8 on the surface of the coated glass in the laser protective cover to form a liquid layer on the surface of the coated glass.

[0027] The matching liquid components include 25% propylene glycol dicaproate with a total volume ratio, 5% carbon tetrachloride with a total volume ratio, 15% diethylene glycol butyl ether acetate with a total volume ratio, 30% bromonaphthalene with a total volume ratio, and 25% propylene glycol with a total volume ratio.

[0028] The laser probe 4 starts to work and emits a circular laser beam 5 downward, and cuts a circular glass piece 1a with a diameter of 10-15mm through the laser beam (a hole of 10-15mm is selected according to customer needs).

[0029] A recovery device 10 for the glass pieces cut off by punching and the matching liquid is arranged below the glass substrate.

[0030] The recycling device 10 includes a recycling tank 10a, a group of pipes 10b corresponding to the laser protection cover 6 are connected in parallel to the top of the recycling tank 10a, and a flared liquid receiving port 10f is connected to the open end of the pipe 10b. The diameter of the liquid receiving port 10f is larger than the diameter of the laser protection cover 6, so that the circular glass pieces cut by the laser and the matching liquid can fall into the pipe 10b smoothly. An exhaust pipe 10e is also connected to one side of the top of the recovery tank body 10a, and a slight negative pressure environment is formed in the recovery tank body through the exhaust pipe 10e, thereby ensuring that the matching liquid in the pipeline 10b flows into the recovery tank body 10a more smoothly.

[0031] An upper and lower filter layer 10c is disposed in the middle of the recovery tank 10a, and the filter layer 10c includes an upper mesh a, a filter core layer b and a lower mesh c which are sequentially distributed from top to bottom. The hole diameters of the upper and lower meshes and the filter hole diameters in the filter core layer in the upper filter layer 10c are larger than the hole diameters of the upper and lower meshes and the filter hole diameters in the filter core layer in the lower filter layer 10c. The filter layer 10c is a sponge layer.

[0032] A recovery pipe 10d is connected to the bottom of the recovery tank 10a, and the other end of the recovery pipe 10d is connected to a liquid tank in a liquid spraying device not shown in the figure. The matching liquid falling into the recovery tank 10a is filtered by the upper and lower filter layers 10c and then enters the liquid spraying device again through the recovery pipe 10d, so that the recovered matching liquid can be recycled.

[0033] The fallen round glass pieces 1a are intercepted by the upper grid a of the upper filter layer 10c located in the upper middle part of the recovery tank 10a. After the punching operation is performed for a certain period of time, the cleaning hole (not shown) on the upper part of the recovery tank 10a is opened to remove the round glass pieces 1a.

[0034] Step S6, tempering treatment, drying and preheating the coated and perforated glass substrate at 200° C. before tempering, and tempering the preheated glass substrate to obtain a coated and perforated photovoltaic backplane glass.

Claims

1. A method for preparing a coated and perforated photovoltaic backplane glass, characterized in that: The method comprises the following preparation steps: S1: substrate preparation, taking ultra-white rolled glass as a glass substrate, and grinding and cleaning the glass substrate; S2: Substrate preparation pretreatment, drying and preheating the glass substrate; S3: Preparation of the bottom film, coating the bottom film using a coating machine in a constant temperature and humidity coating workshop at a temperature of 20°C to 28°C and a humidity of 30% to 45%, and then curing the bottom film at high temperature; S4: preparing the surface film, when the temperature of the glass substrate is cooled to ≤40°C, coating the surface film on the bottom film, and then curing the surface film at high temperature; S5: laser drilling, sending the double-layer coated glass substrate to the laser drilling process, the laser drilling process includes lowering a retractable laser protection cover (6) through a lifting mechanism inside the laser probe assembly of the drilling machine, a liquid spraying pipe (7) of a liquid spraying device is provided inside the laser protection cover, and a laser drilling matching liquid (8) is sprayed on the surface of the coated glass through the liquid spraying pipe (7), wherein the matching liquid composition includes a mixture of propylene glycol dicaprylate (20%-30%), carbon tetrachloride (3%-10%) by volume, diethylene glycol butyl ether acetate (10%-20%), bromonaphthalene (25%-35%), and propylene glycol (15%-25%). A laser probe (4) is also arranged in the laser protection cover (6). When the laser probe (4) starts to work, it emits a circular laser beam (5) to cut off a circular glass piece with a diameter of 10-15 mm from the glass. A recovery device (10) for the glass pieces cut off by punching and matching liquid is provided below the glass, the recovery device (10) comprising a recovery tank (10a), a pipeline (10b) distributed corresponding to the laser protection cover (6) is provided in the recovery tank (10a), a plurality of filter layers (10c) are provided in the middle of the recovery tank (10a), and a recovery pipe (10d) is connected to the bottom of the recovery tank (10a); Step S6, tempering treatment, drying and preheating the coated and perforated glass substrate at 200-250° C. before tempering, and tempering the preheated glass substrate to obtain a coated and perforated photovoltaic backplane glass.

2. A method for preparing a coated and perforated photovoltaic backplane glass according to claim 1, characterized in that: In the drying and preheating treatment in S2, the drying and preheating temperature is controlled between 100° C. and 200° C., and the preheating time is controlled between 15 and 30 seconds.

3. The method for preparing a coated and perforated photovoltaic backplane glass according to claim 1, characterized in that: The recovery tank body (10a) is connected to an exhaust pipe (10e), so that a slightly negative pressure environment is formed inside the recovery tank body.

4. The method for preparing a coated and perforated photovoltaic backplane glass according to claim 1, characterized in that: The filter layer (10c) comprises an upper grid (a), a filter core layer (b) and a lower grid (c) which are arranged in sequence from top to bottom.

5. The method for preparing a coated and perforated photovoltaic backplane glass according to claim 1, characterized in that: The plurality of filter layers (10c) are horizontally and parallelly distributed from top to bottom, and the filter apertures decrease in sequence from top to bottom.

6. A method for preparing a coated and perforated photovoltaic backplane glass according to claim 1, characterized in that: A sealing ring (6a) is provided at the open end of the laser protection cover (6).

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