Method for recycling waste solar panels

Abstract

According to one embodiment of the present invention, a method for recovering a waste solar panel, the solar panel comprises a glass substrate, a solar cell, an adhesive layer arranged between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame configured to fix a laminated structure of the glass substrate, the adhesive layer and the solar cell, the method includes: a crushing process of crushing the waste solar panel into a predetermined size or less; a frame removal process for sorting and removing a frame contained in the crushed material crushed by the crushing process; and putting the final crushed material from which the frame has been removed into a drying furnace putting process among the drying furnaces of the smelting process.

Description

Technical Field

[0001] The present disclosure relates to a method for recycling discarded solar panels. Background Art

[0002] Solar power generation is attracting attention as a renewable energy source because it uses clean sunlight and has a low environmental impact. A solar panel used for solar power generation consists of a glass substrate, solar cells, an adhesive layer (such as ethylene vinyl acetate (EVA)) interposed between the solar cells and the glass substrate to bond the solar cells and the glass substrate together, and an aluminum frame that secures the glass substrate, adhesive layer, solar cells, and the like into a module.

[0003] Regarding the application of solar power generation, the proportion of renewable energy power generation has increased rapidly since the early 2000s, with solar power generation increasing the most.

[0004] As solar power generation systems become more common, the number of used solar panels reaching the end of their lifespan is expected to increase exponentially. Considering that the lifespan of a solar panel is approximately 25 years, a large number of discarded solar panels are expected to begin to appear in the mid- to late 2020s as solar panels installed since the early 2000s approach the end of their lifespan. Accordingly, various methods for processing discarded solar panels are being sought. However, to date, all discarded solar panels have been landfilled without being recycled, or only the aluminum frames have been separated and recycled, and complete recycling of discarded solar modules has not yet been achieved. Specifically, the current existing method for processing discarded solar panels is to manually separate and sell the aluminum frames and glass, while the remaining solar cell parts are landfilled. Some companies have attempted to use machines to semi-automate and automate the process of separating the aluminum frames and glass, but most companies are small-scale and have limited processing capabilities.

[0005] In particular, solar cells, which are rich in silicon and contain large amounts of copper and silver, are difficult to recycle and require a complex process to separate the valuable metals through conventional crushing and sorting methods. Consequently, there is a need to develop recycling methods capable of disposing of solar panels, as well as automated processes capable of processing large numbers of solar panels. Summary of the Invention

[0006] Technical issues

[0007] The method provided by the present disclosure is to place waste solar panels into a smelting furnace for performing a smelting process, thereby replacing the flux made of silicon dioxide (SiO2) used in the smelting process with the waste solar panels to recover valuable metals.

[0008] Additionally, the present disclosure provides methods for recovering valuable metal-concentrated materials from discarded solar panels.

[0009] Solution to the problem

[0010] According to one embodiment of the present invention, a method for recycling waste solar panels includes a glass substrate, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells, and a metal frame configured to secure a laminated structure of the glass substrate, the adhesive layer, and the solar cells. The method comprises: a crushing process for crushing the waste solar panels into a predetermined size or smaller; a frame removal process for sorting and removing frames contained in the crushed material crushed by the crushing process; and a drying furnace feeding process for feeding the final crushed material from which the frames have been removed into a drying furnace of a melting process.

[0011] The waste solar panels are crushed into a size of 50mm or smaller in the crushing process.

[0012] The crushing process is performed by a crusher, and the crushed material crushed into a size of 50 mm or less in the crushing process is discharged through a screen provided at the bottom of the crusher.

[0013] The metal frame is made of aluminum, and the frame removal process is performed by means of an eddy current separator.

[0014] The amount of the final crushed material fed into the drying furnace in the drying furnace feeding process is calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

[0015] According to another embodiment of the present invention, a method for recycling waste solar panels includes a glass substrate, a solar cell, an adhesive layer arranged between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame configured to fix the stacked structure of the glass substrate, the adhesive layer and the solar cell, the method comprising: a crushing process of crushing the waste solar panel into a predetermined size or smaller; a frame removal process of sorting and removing the frame contained in the crushed material crushed by the crushing process; a calcining process of removing the adhesive layer between the glass substrate and the solar cell by placing the crushed material from which the frame has been removed into a calcining furnace and heating the crushed material; a grading process of separating the crushed material that has undergone the calcining process into the glass substrate and the solar cell and removing the glass substrate; and a drying furnace placing process of placing the final crushed material from which the glass substrate has been removed into a drying furnace of a melting process.

[0016] The waste solar panels are crushed into a size of 50mm or smaller in the crushing process.

[0017] The crushing process is performed by a crusher, and the crushed material crushed into a size of 50 mm or less in the crushing process is discharged through a screen provided at the bottom of the crusher.

[0018] The metal frame is made of aluminum, and the frame removal process is performed by means of an eddy current separator.

[0019] The calcination process is performed at a temperature of 500° C. to 600° C. for 2 to 3 hours.

[0020] The adhesive layer is made of ethylene vinyl acetate (EVA), and the ethylene vinyl acetate is removed by burning or sublimation through a calcination process.

[0021] The classification process is performed by screening classification using a particle size difference between the crushed glass substrate and the crushed solar cell.

[0022] The final crushed material from which the glass substrate has been removed contains silicon (Si), silver (Ag), and copper (Cu).

[0023] Silver and copper are concentrated in the final crushed material of the classification process.

[0024] The amount of the final crushed material fed into the drying furnace in the drying furnace feeding process is calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

[0025] Effects of the Invention

[0026] According to the present invention, recycled casting sand (including SiO2) used as a flux in the smelting process can be replaced by discarded solar panels.

[0027] Additionally, valuable metals such as silver and copper contained in discarded solar panels can be concentrated and recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart of a method for recycling waste solar panels according to one embodiment of the present invention.

[0029] Figure 2 FIG. 4 is a process flow chart of a method for recycling waste solar panels according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] In describing the present disclosure, when it is determined that a related known function is obvious to those skilled in the art and a detailed description of the function unnecessarily obscures the gist of the present disclosure, the detailed description will be omitted.

[0031] This disclosure relates to a method for recycling discarded solar panels using an existing smelting process. The recycling method according to this disclosure primarily utilizes discarded solar panels, but is not necessarily limited thereto. The recycling method according to this disclosure can be applied to any industrial waste containing silicon and valuable metals.

[0032] The present disclosure provides a method for treating waste solar panels and feeding the treated waste solar panels into a drying furnace for a conventional smelting process, thereby replacing silicon dioxide fed into the smelting process and recovering valuable metals contained in the waste solar panels.

[0033] Figure 1 The present invention is a process flow chart of a method for recycling waste solar panels according to one embodiment of the present invention.

[0034] The recycled waste solar panel using the present disclosure includes a glass substrate, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells, and a metal frame configured to fix the stacked structure of the glass substrate, the adhesive layer and the solar cells and disposed on the peripheral edge of the solar panel.

[0035] refer to Figure 1 The waste solar panels are placed in a crusher and crushed to a size of 50 mm or less (crushing process S1). Crushing process S1 is performed using a crusher, wherein the waste panels are crushed to a size of 50 mm or less using crushing process S1, and the crushed waste panels are discharged through a screen provided at the bottom of the crusher. Any mechanical device capable of crushing the glass substrates, solar cells, metal frames, and the like contained in the waste solar panels can be used as the mechanical device for performing crushing process S1. For example, a known crusher such as a single-shaft crusher or a double-shaft crusher can be used.

[0036] The crushed material crushed in the crushing process S1 is transferred to the frame removal process S2, and the metal frame material contained in the crushed material is sorted and removed from the crushed material in the frame removal process S2. The crushed material obtained by crushing the waste solar panels contains the metal frame material of the laminated structure that fixes the waste solar panels, and the metal frame can be made of aluminum. The crushed material containing the crushed aluminum frame is transferred to the eddy current separator, and the eddy current separator is capable of sorting and removing the crushed aluminum frame from the crushed material. The eddy current separator uses eccentric eddy current technology to sort small crushed and lightweight non-ferrous metals such as aluminum, and is equipped with an adjustable angle magnet, which has a strong magnetic field capable of sorting and separating the aluminum component contained in the crushed material.

[0037] The final crushed material, from which the aluminum frame has been removed in the frame removal process S2, is fed into the drying furnace of the smelting process (the drying furnace is fed into the process S3). By recycling the final crushed material, including solar cells containing silicon (Si), silver (Ag), and copper (Cu), and crushed glass substrates, as flux and fuel in the smelting process, valuable metals such as silver and copper can be recovered from discarded solar panels, significantly reducing the amount of flux and fuel fed into the smelting process.

[0038] Specifically, flux is added to the smelting process to increase the fluidity of the melt, and this is particularly necessary when using metal waste as the raw material. This is because natural ores contain large amounts of flux components such as SiO2 and Al2O3, but these flux components are not present in sufficient quantities in metal waste. Therefore, the addition of flux is essential to the metal waste smelting process, and previously, sand or recycled foundry sand was primarily used as a silica (SiO2) flux. In the present disclosure, final crushed material obtained from discarded solar panels, containing silicon (Si), silver (Ag), copper (Cu), and the like, is fed into a drying furnace in the smelting process. In the drying furnace, the silicon (Si), the primary component of the final crushed material, reacts with oxygen to produce silica (SiO2), thereby acting as a flux. In other words, the flux made of silica (SiO2) fed into the smelting process can be replaced by recycled discarded solar panels by feeding them into the smelting furnace to recover valuable metals. The amount of the final crushed material fed into the drying furnace in the drying furnace feeding process S3 may be calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

[0039] Figure 2 FIG. 4 is a process flow chart of a method for recycling waste solar panels according to another embodiment of the present disclosure.

[0040] refer to Figure 2 The waste solar panels are placed in a crusher and crushed into a size of 50 mm or less (crushing process S10). The crushing process S10 according to the embodiment of the present invention is the same as the crushing process S1 according to the above embodiment, and redundant description is omitted below.

[0041] The crushed material crushed in the crushing process S10 is transferred to the frame removal process S20, and the metal frame material contained in the crushed material is sorted and removed from the crushed material in the frame removal process S20. The frame removal process S20 according to the embodiment of the present invention is the same as the frame removal process S20 according to the above embodiment, and redundant description is omitted below.

[0042] The crushed material, from which the aluminum frame has been removed in the frame removal process S20, is then fed into a calcination process S30. In calcination process S30, the crushed material is placed in a calcination furnace and heated to remove the adhesive layer between the glass substrate and the solar cell. The adhesive layer can be made of ethylene vinyl acetate (EVA). Calcination process S30 can be performed in a calcination furnace at a temperature of 500°C to 600°C for 2 to 3 hours. The EVA adhesive layer between the glass substrate and the solar cell can be burned or sublimated during calcination process S30, removing it from the crushed material. Upon completion of calcination process S30, the adhesive layer is removed, leaving only the crushed glass substrate and solar cell. Notably, the solar cell remains in powder form after the high-temperature calcination process, while the crushed glass substrate has a similar particle size as before entering the calcination furnace.

[0043] The crushed material that has undergone the calcination process S30 contains crushed glass substrates and solar cells, and the glass substrates and solar cells included in the crushed material can be separated through the classification process S40. The classification process S40 can be implemented by screening and classification using the difference in particle size between the glass substrates and solar cells contained in the crushed material after the calcination process S30. After undergoing the calcination process S30, the crushed material contains solar cells in powder form and glass substrates with larger particle size than the solar cells. Therefore, the glass substrates with larger particle size can be separated from the powdered solar cells and removed through the classification process S40. The powdered solar cells from which the glass substrates have been removed are the final crushed material and may contain silicon (Si), silver (Ag), copper (Cu), and the like.

[0044] As described above, by removing the glass substrate, resin, and other impurities through the classification process S40 , valuable metals such as silver and copper contained in the solar cell can be concentrated.

[0045] The final crushed material, from which the glass substrate has been removed in the classification process S40, is fed into the drying furnace of the smelting process (drying furnace feeding process S50). By recycling the final crushed material containing silicon (Si), silver (Ag), and copper (Cu) as flux and fuel for the smelting process, not only can valuable metals such as silver and copper be recovered from discarded solar panels, but the amount of flux and fuel used in the smelting process can also be significantly reduced.

[0046] Specifically, flux is added to the smelting process to increase the fluidity of the melt, and this is particularly necessary when using metal waste as the raw material. This is because natural ores contain large amounts of flux components such as SiO2 and Al2O3, but these flux components are not present in sufficient quantities in metal waste. Therefore, the addition of flux is essential to the metal waste smelting process, and previously, sand or recycled foundry sand was primarily used as a silica (SiO2) flux. In the present disclosure, final crushed material obtained from discarded solar panels, containing silicon (Si), silver (Ag), copper (Cu), and the like, is fed into a drying furnace in the smelting process. In the drying furnace, the silicon (Si), the primary component of the final crushed material, reacts with oxygen to produce silica (SiO2), thereby acting as a flux. In other words, the flux made of silica (SiO2) fed into the smelting process can be replaced by recycled discarded solar panels by feeding them into the smelting furnace to recover valuable metals. The amount of the final crushed material fed into the drying furnace in the drying furnace feeding process S50 may be calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

[0047] Although the present disclosure has been described in conjunction with some of its embodiments, it should be understood that various modifications and changes that are obvious to those skilled in the art to which the present disclosure belongs can be made without departing from the spirit and scope of the present disclosure. In addition, such modifications and changes should be deemed to fall within the scope of the claims appended hereto.

Claims

1. A method for recycling discarded solar panels, the solar panels comprising a glass substrate, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells together, and a metal frame configured to secure the stacked structure of the glass substrate, the adhesive layer, and the solar cells. The method comprises: A crushing process for crushing the discarded solar panels into a predetermined size or smaller; a frame removal process for sorting and removing frames contained in the crushed material crushed by the crushing process; and The final crushed material from which the frame has been removed is fed into a drying furnace of a smelting process.

2. The method according to claim 1, wherein the waste solar panels are crushed into a size of 50 mm or less in the crushing process.

3. The method according to claim 2, wherein the crushing process is performed by a crusher, and The crushed material crushed into a size of 50 mm or less in the crushing process is discharged through a screen provided at the bottom of the crusher.

4. The method according to claim 1, wherein the metal frame is made of aluminum, and The frame removal process is performed by an eddy current separator.

5. The method according to claim 1, wherein the amount of the finally crushed material fed into the drying furnace in the drying furnace feeding process is calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

6. A method for recycling discarded solar panels, the solar panels comprising a glass substrate, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells together, and a metal frame configured to secure the stacked structure of the glass substrate, the adhesive layer, and the solar cells, the method comprising: A crushing process for crushing the discarded solar panels into a predetermined size or smaller; a frame removal process for sorting and removing frames contained in the crushed material crushed by the crushing process; a calcining process of removing an adhesive layer between the glass substrate and the solar cell by placing the crushed material from which the frame has been removed into a calcining furnace and heating the crushed material; a classification process of separating the crushed material subjected to the calcining process into the glass substrate and the solar cell and removing the glass substrate; and The final crushed material from which the glass substrate has been removed is fed into a drying furnace of a melting process.

7. The method according to claim 6, wherein the waste solar panels are crushed into a size of 50 mm or less in the crushing process.

8. The method according to claim 7, wherein the crushing process is performed by a crusher, and The crushed material crushed into a size of 50 mm or less in the crushing process is discharged through a screen provided at the bottom of the crusher.

9. The method according to claim 6, wherein the metal frame is made of aluminum, and The frame removal process is performed by an eddy current separator. 10 . The method according to claim 6 , wherein the calcining process is performed at a temperature of 500° C. to 600° C. for 2 to 3 hours.

11. The method according to claim 10, wherein the adhesive layer is made of ethylene vinyl acetate (EVA), and The ethylene vinyl acetate is removed by combustion or sublimation through the calcination process. 12 . The method according to claim 6 , wherein the classification process is performed by screening classification using a particle size difference between the crushed glass substrate and the crushed solar cells. 13 . The method according to claim 12 , wherein the final crushed material from which the glass substrate has been removed contains silicon (Si), silver (Ag), and copper (Cu).

14. The method of claim 13, wherein the silver and the copper are concentrated by the final crushed material of the classification process.

15. The method according to claim 6, wherein the amount of the final crushed material fed into the drying furnace in the drying furnace feeding process is calculated based on the composition ratio of silicon dioxide in the flux fed into the melting process.

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