A method for disposing of broken crystalline silicon photovoltaic modules

Abstract

This invention relates to the fields of environmental protection and photovoltaic module recycling, and discloses a method for disposing of broken crystalline silicon photovoltaic modules. The method involves fixing and winding the discarded broken photovoltaic modules (after removing the aluminum frames) onto a roller. A rotating needle is used to separate the broken tempered glass from the surface, leaving a mixture of EVA film, crystalline silicon cells, and a backsheet. The remaining mixture after glass separation is then subjected to light irradiation for no more than 20 seconds. This irradiation process separates the upper EVA film from the crystalline silicon cells and the lower EVA film from the backsheet. This invention uses a light irradiation method, eliminating the need for physical crushing and screening steps, as well as chemical agents, thus saving on the cost of disposing of broken photovoltaic modules. Furthermore, removing the glass before irradiation avoids some light source interception by the glass, ensuring that all energy released by the light source is absorbed by the EVA and crystalline silicon cell layers of the module, thereby guaranteeing the effective separation of the various structures within the photovoltaic module.

Description

Technical Field

[0001] This invention relates to the fields of environmental protection and photovoltaic module recycling, and specifically to a method for disposing of broken crystalline silicon photovoltaic modules. Background Technology

[0002] Crystalline silicon photovoltaic (PV) modules, as a crucial component of modern renewable energy technology, are widely used globally. These modules typically employ a sandwich structure design, where the solar cells are primarily composed of silicon (Si) and silver (Ag), encapsulated by ethylene vinyl acetate (EVA) on a front glass and polymer backsheet. This design not only ensures the module's durability in outdoor environments but also improves its photoelectric conversion efficiency. However, over time, especially after approximately 25 years of use, the power generation efficiency of these modules significantly decreases, no longer meeting the demands for high-efficiency power generation. At this point, photovoltaic power plants typically replace these aging modules, generating substantial amounts of solid waste.

[0003] Directly disposing of these discarded photovoltaic modules in landfills not only represents a massive waste of reusable resources but also poses potential environmental hazards. For example, valuable materials like silicon and silver fail to be recycled, while organic materials such as EVA encapsulation materials may release harmful substances during landfilling, leading to soil and groundwater pollution. Therefore, adopting appropriate treatment methods to manage and recycle these modules is crucial, not only to avoid health and environmental problems associated with such waste disposal but also to promote the efficient use of resources.

[0004] Currently, the disposal methods for waste crystalline silicon photovoltaic modules include physical separation, chemical treatment, mechanical crushing, and pyrolysis. Physical separation involves separating different materials within the photovoltaic module, such as glass, metal frames, and backsheets. Chemical treatment allows for the extraction of valuable materials like silicon and silver from the cells. Mechanical crushing breaks the cells into smaller fragments for easier processing. Pyrolysis decomposes the EVA encapsulation material through high-temperature treatment, recovering its organic components. However, all of these methods suffer from drawbacks such as high processing costs, high energy consumption, complex processes, and the potential for secondary pollution. Summary of the Invention

[0005] The present invention aims to provide a method for disposing of broken crystalline silicon photovoltaic modules, so as to achieve effective separation of broken crystalline silicon photovoltaic modules.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for disposing of broken crystalline silicon photovoltaic modules, wherein the photovoltaic module after the frame is removed is fixed and wound on a roller, and the broken tempered glass on the surface of the photovoltaic module is removed by the rotation of the roller and the rotating needle assembly, and the remaining mixture of EVA film, crystalline silicon cells and backsheet is subjected to light irradiation treatment.

[0007] The principle and advantages of this solution are as follows: In practical applications, in existing technologies, after traditional physical glass removal, a layer of glass shards still adheres to the EVA film. When photovoltaic modules are directly irradiated using light, the glass filters out some wavelengths of light, weakening the energy of the light source and reducing the effectiveness of light separation. However, this technical solution, for the treatment of waste photovoltaic modules, uses a combination of rotating needle separation and irradiation, which does not further damage the glass, and the glass is completely separated from the EVA film. During the rotation process of the rotating needle separating the glass, in addition to the force that detaches the glass from the film, the friction between the rotating needle and the film during high-speed rotation generates heat, softening the local contact points of the film and facilitating glass separation. The light source used for irradiation directly damages the UV resistance of the EVA film. The strong UV energy denatures the EVA film, and the deformation and degradation of the EVA film leads to the breakage of the crystalline silicon solar cells. In addition, the energy released by the light source can penetrate the EVA film and reach the crystalline silicon cell layer. The energy absorbed by the crystalline silicon cell raises the temperature of the silicon wafer and reaches the lower EVA layer, causing the crystalline silicon to separate from the lower EVA film.

[0008] The beneficial effects of this technical solution are as follows:

[0009] (1) This technical solution uses the light irradiation method, which does not require physical crushing, screening or other steps, nor chemical agents, thus saving the cost of disposing of broken photovoltaic modules.

[0010] (2) This technical solution has high efficiency in handling broken components.

[0011] (3) This technical solution can avoid the risk of explosion caused by uneven energy reception in some parts of the component when it is illuminated, thus ensuring the safety of the light source to a greater extent.

[0012] (4) The technical solution of removing the glass before irradiation can avoid some of the light source being blocked by the glass, ensuring that all the energy released by the light source is absorbed by the EVA and crystalline silicon cell layers of the module, thereby ensuring the separation and treatment effect. As a result, the light energy required by this solution is lower than that required to irradiate the complete module.

[0013] Preferably, as an improvement, the needle rotating assembly includes a needle body and a motor, with the motor fixed at the end away from the needle tip.

[0014] In this technical solution, the click is used to drive the needle body to rotate, and the glass can be removed during the rotation of the needle body, which is convenient to operate.

[0015] Preferably, as an improvement, the needle body is a solid needle structure with a diameter of 1-3 mm and a length of 45-55 cm.

[0016] In this technical solution, by setting the needle body as a solid structure and combining it with a strong rigid material, the durability of the needle body can be guaranteed. The optimization of the diameter and length of the needle body is determined by taking into account the difficulty of insertion, the friction intensity during the peeling process, and the length of the roller. It is a better size range that has been verified in practice.

[0017] Preferably, as an improvement, the rotational speed of the needle body is ≥3500 rpm.

[0018] In this technical solution, the rotation speed determines whether the glass can be separated cleanly. Only within the aforementioned rotation speed range can the needle achieve efficient glass removal. At the same time, the needle can generate a certain amount of heat through friction with the adhesive film during high-speed rotation, which can soften the local contact points of the adhesive film and make it easier for the glass to separate.

[0019] Preferably, as an improvement, the circumference of the roller is ≥2m.

[0020] In this technical solution, by optimizing the length of the roller shaft, the winding requirements of photovoltaic modules can be met, and it is compatible with the size of most photovoltaic modules, ensuring that the processing has broad applicability.

[0021] Preferably, as an improvement, when using the rotating needle assembly to remove broken glass, the needle is placed horizontally from both ends of the photovoltaic module into the gap in the tempered glass that cannot be fitted due to the curvature of the roller, and contacts the EVA film layer. The motor is turned on to make the needle rotate, and the broken glass is separated as the roller rotates.

[0022] Preferably, as an improvement, the illumination treatment utilizes an inert gas pulse discharge light source to irradiate the photovoltaic module.

[0023] Preferably, as an improvement, the inert gas pulse discharge light source is a pulsed xenon lamp with an irradiation time of ≤20s.

[0024] Preferably, as an improvement, the pulsed xenon lamp is manufactured using a lamp tube glass metallization process.

[0025] In this technical solution, irradiation with a light source directly damages the UV resistance of the EVA film. Strong UV energy denatures the EVA film, causing deformation and degradation, which leads to the breakage of the crystalline silicon solar cell. Part of the energy released by the irradiation light source penetrates the EVA film to reach the crystalline silicon solar cell layer. The energy absorbed by the crystalline silicon cell raises its temperature, transferring heat to the underlying EVA layer, causing the crystalline silicon to separate from the lower EVA film. The pulsed xenon lamp employs a metallized lamp tube manufacturing process, achieving a high-strength hermetically sealed bond between the quartz glass and the metal, thus better ensuring the lamp tube's lifespan. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the rotating needle assembly in an embodiment of the present invention. Detailed Implementation

[0027] The following detailed description provides further details on specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials and reagents used are all commercially available.

[0028] The reference numerals in the accompanying drawings include: needle body 1, motor 2.

[0029] Overview of the plan:

[0030] A method for disposing of broken crystalline silicon photovoltaic modules involves fixing and winding the waste broken photovoltaic modules after the aluminum frames have been removed onto a roller. After removing the broken tempered glass from the surface of the photovoltaic modules using a rotating needle assembly, the remaining mixture of EVA film, crystalline silicon cells, and backsheet is subjected to light irradiation treatment. After light irradiation treatment, the upper EVA film can be separated from the crystalline silicon cells, and the lower EVA film can be separated from the backsheet.

[0031] There are two rotating needle assemblies, and each rotating needle assembly includes a needle body 1 ( Figure 1 The diameter of each needle body 1 is 1-3mm, and the length of each needle body 1 is 50cm. Each needle body 1 is a solid needle. A motor 2 is fixedly connected to the end of the needle body 1 furthest from the needle tip. The motor 2 is fixedly mounted (it can be fixed to the frame) and is used to control the rotation of the needle body 1, ensuring that the rotation speed of the needle body 1 is ≥3500rpm. A roller (not shown in the figure) is provided on the side of the rotating needle assembly, and the roller is controlled to rotate by a drive motor.

[0032] In use, the discarded photovoltaic modules with disassembled aluminum frames are fixed onto the roller, making it cylindrical. The circumference of the roller should be sufficient to wrap around a 2m long photovoltaic module once. Two needles 1 are inserted horizontally into the gaps in the tempered glass caused by the roller's curvature, from both ends of the photovoltaic module (i.e., both ends of the roller), and into the EVA film layer. The motor 2 is then turned on to make the needles 1 rotate at high speed. As the roller rotates, the broken glass is separated.

[0033] The mixture of remaining EVA film, crystalline silicon solar cells, and backsheet (after glass removal) is then subjected to photo-irradiation. This photo-irradiation utilizes an inert gas pulsed discharge light source to provide short-term, high-efficiency irradiation of the photovoltaic module. The pulsed discharge light source is a pulsed xenon lamp, which releases high-energy short-wave ultraviolet light (the wavelength of which is very close to the bond energy in the EVA film, making it easily absorbed by EVA and causing chemical bond breakage). The ultraviolet index is 10-15, and the irradiation time is ≤20 seconds. After photo-irradiation, the upper EVA film can be separated from the crystalline silicon solar cells, and the lower EVA film can be separated from the backsheet.

[0034] Example 1

[0035] A method for disposing of broken crystalline silicon photovoltaic modules includes the following steps:

[0036] S1. Disassemble the aluminum frame of the waste and broken photovoltaic module, then fix the remaining module and wrap it around the roller. The circumference of the roller is just enough to wrap the module around once.

[0037] S2. Insert the rotating needle into the gap in the tempered glass where it cannot be properly fitted due to the curvature of the roller, and turn on the motor to start the needle rotating at 3500 rpm. As the needle rotates, the broken tempered glass separates and falls off. What remains is a mixture of EVA film, crystalline silicon solar cells, and backsheet.

[0038] S3. Remove the remaining components after separating the glass from the roller and fix them on the illumination platform. Adjust the distance between the platform and the light source and perform 10 seconds of illumination treatment. After illumination, external force can be used to separate the upper EVA film, crystalline silicon solar cells, and backsheet.

[0039] Comparative Example 1

[0040] A method for disposing of broken crystalline silicon photovoltaic modules includes the following steps:

[0041] S1. Disassemble the aluminum frame of the waste and broken photovoltaic module, then fix the remaining module and wrap it around the roller. The circumference of the roller is just enough to wrap the module around once.

[0042] S2. Insert the rotating needle into the gap in the tempered glass where it cannot be properly fitted due to the curvature of the roller, and turn on the motor to start the needle rotating at 2800 rpm. As the needle rotates, the broken tempered glass separates and falls off. Occasionally, there may be some jamming during the rotation. What remains is a mixture of EVA film, crystalline silicon solar cells, and backsheet.

[0043] S3. Remove the remaining components after separating the glass from the roller and fix them on the illumination platform. Adjust the distance between the platform and the light source and perform 20 seconds of illumination treatment. After illumination, the upper EVA film, crystalline silicon solar cells, and backsheet can be easily separated.

[0044] Comparative Example 2

[0045] A method for disposing of broken crystalline silicon photovoltaic modules includes the following steps:

[0046] S1. Disassemble the aluminum frame of the waste and broken photovoltaic module, then fix the remaining module and wrap it around the roller. The circumference of the roller is just enough to wrap the module around once.

[0047] S2. Insert the rotating needle into the gap in the tempered glass where it cannot be properly fitted due to the curvature of the roller, and turn on the motor to start the needle rotating at 4000 rpm. As the needle rotates, the broken tempered glass separates and falls off. What remains is a mixture of EVA film, crystalline silicon solar cells, and backsheet.

[0048] S3. Remove the remaining components after separating the glass from the roller and fix them on the illumination platform. After adjusting the distance between the platform and the light source, perform a 5-second illumination treatment. After illumination, the upper EVA film, crystalline silicon solar cells, and backsheet can be separated, but some separation may be incomplete.

[0049] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for disposing of broken crystalline silicon photovoltaic modules, characterized in that: After the photovoltaic module with the frame removed is fixed and wrapped around the roller, the broken tempered glass on the surface of the photovoltaic module is removed by the rotation of the roller and the rotating needle assembly. The remaining mixture of EVA film, crystalline silicon cells and backsheet is then treated with light. When removing the broken glass with the rotating needle assembly, the needle is inserted horizontally from both ends of the photovoltaic module into the gap in the tempered glass that cannot be fitted due to the curvature of the roller, and it contacts the EVA film layer. The motor is turned on to make the needle rotate, and the broken glass is separated as the roller rotates.

2. The method for disposing of broken crystalline silicon photovoltaic modules according to claim 1, characterized in that: The rotating needle assembly also includes a motor, which is fixed at the end away from the needle tip.

3. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 2, characterized in that: The needle body is a solid needle structure with a diameter of 1~3mm and a length of 45-55cm.

4. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 3, characterized in that: The rotational speed of the needle body is ≥3500 rpm.

5. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 1, characterized in that: The circumference of the roller is ≥2m.

6. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 1, characterized in that: The illumination treatment is performed using an inert gas pulse discharge light source.

7. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 6, characterized in that: The inert gas pulse discharge light source is a pulsed xenon lamp with an irradiation time of ≤20s.

8. A method for disposing of broken crystalline silicon photovoltaic modules according to claim 7, characterized in that: The pulsed xenon lamp is manufactured using a process that metallizes the lamp tube glass.

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