A method for recycling all components of waste photovoltaic modules

Abstract

This invention relates to a method for recycling waste photovoltaic modules, belonging to the field of resource recycling. The method mainly includes three parts: module dismantling, ethylene-vinyl acetate copolymer (EVA) separation, and resource utilization of solar cells. First, the aluminum frame and junction box of the waste photovoltaic module are dismantled. Then, tempered glass, backsheet, and solar cells are separated using thermal cutting. The solar cells are crushed and sorted to obtain tin-plated copper strips and solar cell powder. Silver is recovered and silicon nitride with the antireflective layer is removed using acid leaching. The silver leaching solution is purified and refined to obtain silver with a purity of over 99.95%. The silicon powder is then combined with aluminum to synthesize a silicon-aluminum alloy. This method has advantages such as simple process, green operation, high efficiency, low cost, and high product value, making it suitable for industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling, and specifically relates to a method for recycling and utilizing waste photovoltaic modules. Background Technology

[0002] Photovoltaic modules include crystalline silicon photovoltaic modules and thin-film photovoltaic modules, with crystalline silicon photovoltaic modules being the primary type. After they are scrapped, they become valuable secondary resources. Crystalline silicon photovoltaic modules are further divided into two main categories: polycrystalline silicon and monocrystalline silicon, both of which have similar structures. Silicon-based photovoltaic modules mainly consist of solar cells, organic encapsulation layers, cover glass, backsheets, frames, and junction boxes.

[0003] For example, Chinese invention patent (application number: CN201811140353.6) discloses a method for recycling and reusing waste photovoltaic modules. This method uses dilute nitric acid to dissolve silver and aluminum in the photovoltaic modules, then obtains elemental silver through chloride precipitation-ammonia leaching-hydrazine hydrate reduction, and recovers aluminum hydroxide through sodium hydroxide precipitation. This method achieves the recovery of silver and aluminum from photovoltaic modules, but it does not address key issues such as dismantling, EVA removal, and silicon powder reuse.

[0004] Chinese invention patent (application number: CN201911182539.2) discloses a method combining physical, chemical, and thermal processes to recycle waste photovoltaic modules. The method involves shredding the disassembled photovoltaic module body into module particles, sieving to obtain backsheet copper wire particles, glass particles with a small portion of the solar cells adhered to them, and glass particles with most of the solar cells adhered to them. After the copper wire is selected, the remaining backsheet undergoes combustion or chemical treatment, using hydrochloric acid and nitric acid to extract precious metals. While the method is relatively simple, it does not disclose the disassembly method or the removal of EVA from the remaining backsheet and glass particles. Furthermore, the glass particles have low value, and the reuse of silicon powder is not addressed.

[0005] Chinese invention patent (application number: CN202110606192.0) discloses a method for separating and recycling photovoltaic modules. This method uses friction to obtain backsheet particles, then uses heating to soften EVA to separate the solar cells from the glass, and finally recovers the silicon solar cells through high-temperature calcination. While this method achieves the separation of the solar modules, the high-temperature calcination generates waste gas that pollutes the environment, and it does not disclose a recycling scheme for silver and silicon.

[0006] Chinese invention patent (application number: CN201810632754.7) discloses a method for dismantling scrapped photovoltaic modules. This method involves using an automatic frame dismantling machine to remove the aluminum frame, manual disassembly of the junction box using blades, a spray gun to remove the fluorine film and separate the EVA adhesive layer, and centrifugal separation of the silicon wafer, glass, and backsheet. This method has low processing efficiency, and the mixture of the fluid in the spray gun with the module particles is difficult to separate. The glass is severely damaged and cannot be recycled. Furthermore, the recovery rate of silicon powder and precious metals is low.

[0007] Chinese invention patent (application number: CN201911204948.8) discloses a method for preparing nano-silicon powder by recycling silicon from waste photovoltaic modules. The method involves crushing waste photovoltaic silicon wafers and then preparing nano-silicon powder using a plasma reactor. The resulting silicon powder has advantages such as high purity, fine particle size, uniform distribution, good sphericity, and good dispersibility. However, due to the lack of impurity removal, the silicon powder contains high levels of impurity elements, which significantly affects the performance of lithium-ion battery anode materials. Furthermore, the absence of silver recovery results in low economic efficiency.

[0008] In summary, none of the above methods can achieve green and efficient recycling of scrap photovoltaic modules. The main problems are: (1) efficient dismantling of scrap photovoltaic modules; (2) efficient separation of tempered glass, solar cells, backsheet and EVA; (3) high-value utilization of tempered glass and aluminum frame; and (4) green and efficient recycling of valuable components such as silver and silicon powder. Therefore, it is urgent to develop green and efficient recycling methods for scrap photovoltaic modules to achieve high-value utilization of all components of scrap photovoltaic modules. Summary of the Invention

[0009] To address the problems of low dismantling efficiency, difficulty in removing EVA adhesive, downgrading of tempered glass and aluminum frames, and low recovery rates of silver and silicon powder in existing waste photovoltaic modules, this invention proposes a green and efficient method for the full-component recycling of waste photovoltaic modules. The method involves first dismantling the aluminum frame and junction box, then using thermal cutting to separate the tempered glass, backsheet, and solar cells. After crushing and sorting, the solar cells are purified by acid dissolution and separation. Silicon powder is smelted with aluminum to obtain a silicon-aluminum alloy. This method achieves green and efficient recycling of waste photovoltaic modules, offering advantages such as simple process, high efficiency, low cost, and high product value.

[0010] The present invention adopts the following technical solution, and the method includes the following steps:

[0011] S1: Disassembly: Disassemble the waste photovoltaic modules to obtain aluminum frames, junction boxes and encapsulation layers;

[0012] S2: EVA separation: Thermal cutting of EVA is used to separate the backplane, glass plate and battery cells of the encapsulation layer;

[0013] S3: Cell crushing and sorting: The cells are crushed and sorted to obtain tin-plated copper strips and cell powder;

[0014] S4: Silver and antireflection layer removal: The cell powder is placed in the leaching solution to extract silver and remove the antireflection layer, resulting in a silver-containing leaching solution and silicon powder;

[0015] S5: Silver separation and purification: Silver is purified through a process of chlorination precipitation-ammonia complexation-hydrazine hydrate reduction, with a purity of over 99.95%.

[0016] S6: Silicon powder alloying: Silicon powder is alloyed with aluminum to prepare aluminum alloys or aluminum-silicon intermediate alloys.

[0017] Furthermore, the photovoltaic module is a silicon-based photovoltaic module, including polycrystalline silicon and monocrystalline silicon photovoltaic modules.

[0018] Furthermore, in step S1, the aluminum frame is heated to 300-350℃. After the silicone inside the frame softens, hydraulic derivetization is used to efficiently disassemble the aluminum frame. Hydraulic derivetization involves fixing the scrapped photovoltaic module and using hydraulic pressure to remove the aluminum frame from the photovoltaic module. The separated aluminum frame is then melted, mixed with different components, and recycled for high-quality preservation.

[0019] Furthermore, in step S2, the thermal cutting temperature is 150-200℃, and the thermal cutting method includes any one of laser cutting, wire cutting, or blade cutting. The resulting glass plate is placed at 250-300℃ to pyrolyze the residual EVA. Then, impurities on the glass plate surface are removed by ultrasonic cleaning. Finally, scratches are removed by high-speed friction of polishing powder and polishing brush on the glass surface, improving the light transmittance and refractive effect of the glass, thus realizing the high-value recycling of tempered glass.

[0020] Furthermore, in step S3, the separation is carried out by either gravity separation or sieving to separate the battery cell powder and the tin-plated copper strip, wherein the particle size of the battery cell powder is ≤1.0 mm.

[0021] Further, in step S4, nitric acid or a mixture of acid, chloride salt, and oxidant is used as the leaching agent. The acid includes any one or two of hydrochloric acid and sulfuric acid; the chloride salt includes any one or more of sodium chloride, potassium chloride, magnesium chloride, and calcium chloride; and the oxidant includes any one or more of hydrogen peroxide, sodium chlorate, and sodium hypochlorite. When nitric acid is used as the leaching agent, the nitric acid concentration is 1.0-6.0 mol∙L⁻¹. -1 The solid-liquid ratio is 1:3-1:10, and the temperature is 20-90℃. When using a mixture of acid, chloride salt, and oxidant as the leaching agent, the acid concentration is 1.0-6.0 mol∙L⁻¹. -1 Chloride ion concentration ≥ 6.0 mol∙L -1 Oxidizing agent concentration 10-50 g∙L -1 Solid-liquid ratio 1:5-1:10, temperature 70-90℃.

[0022] Furthermore, in step S5, the chloride ion concentration is controlled to be 0.01 mol∙L⁻¹ during the chlorination precipitation process. -1 ~0.5 mol∙L -1 After filtration, silver chloride is dissolved by complexation with ammonia water to obtain silver ammonia solution. Impurity cations form hydroxide precipitates, thereby further removing impurities. Finally, silver powder is obtained by reduction with hydrazine hydrate. After drying, the purity of the silver powder is above 99.95%, and the recovery rate is above 99.0%.

[0023] Furthermore, impurity elements are dissolved and removed simultaneously during the acid dissolution and silver extraction process, resulting in silicon powder with a purity of over 99.0%. To prevent high-temperature oxidation of the silicon powder, the alloying process employs an immersion method for adding silicon powder, ultimately yielding an aluminum-silicon alloy.

[0024] The principle of this invention is as follows:

[0025] (1) The battery cells, tempered glass, and backsheet are bonded together with EVA to form a battery module encapsulation layer, which protects the battery cells and isolates them from the air. Since the softening temperature of EVA is 80-120℃, the battery cells, tempered glass, and backsheet can be separated by cutting under a certain degree of overheating, while avoiding the decomposition of EVA, thereby eliminating the generation of organic pollutants;

[0026] (2) Based on the difference in brittleness and toughness between silicon wafers and tin-plated copper strips, silicon wafers are pulverized by crushing, while tin-plated copper strips are kept in strip shape due to their good toughness. According to the differences in density, size and shape, tin-plated copper strips and silicon powder are separated efficiently by gravity sorting or sieving.

[0027] (3) The battery cell mainly contains silicon powder, silver, as well as boron, phosphorus, tin, silicon nitride, aluminum oxide, aluminum, etc. On the one hand, during the acid leaching process to recover silver, impurity elements are dissolved and removed by oxidation and acid reaction; when the leaching agent is acid + chloride salt + oxidant, silver is first oxidized to form silver chloride, and then complexed and dissolved with chloride ions. The principle of silver dissolution is as follows (taking hydrogen peroxide as an example of oxidant):

[0028] 2Ag + 2H + + H2O2 + 2Cl - → 2AgCl↓ + 2H2O

[0029] AgCl + Cl - → [AgCl2] -

[0030] As can be seen from the above reaction formula, increasing the chloride ion concentration in the leachate can enhance the complexing ability of silver, thereby increasing the solubility of silver; conversely, it will precipitate as silver chloride.

[0031] On the other hand, the antireflection layer silicon nitride is highly reactive and is also oxidized and dissolved, thereby achieving the dual purpose of silver extraction and impurity removal.

[0032] The key technical point of this invention is:

[0033] 1. Multiple methods, such as hydraulic derivation, thermal cutting, and adjustment of the leaching agent structure, have been adopted to achieve the full recycling of waste photovoltaic modules.

[0034] 2. By controlling the heating temperature to heat the aluminum frame and then using hydraulic derivation, the aluminum frame can be efficiently disassembled. This achieves the goal of preserving and recycling both tempered glass and the aluminum frame, while also preventing the decomposition of EVA, thus eliminating the generation of organic pollutants and making it environmentally friendly.

[0035] 3. Addressing the characteristic of discarded photovoltaic devices containing large amounts of copper, silver, silicon, and aluminum, this study utilizes the physicochemical properties of these materials. First, tin-plated copper strips are efficiently recovered through crushing and sorting. Then, acid leaching is employed to extract silver and remove impurities, improving both silver recovery rate and silicon powder purity. The choice of leaching agent is crucial for enhancing both silver recovery rate and silicon powder purity. Through repeated experiments, the research team discovered that using nitric acid or an acid + chloride salt + oxidant as the leaching agent yields significantly better results than other single acid leaching methods. Furthermore, the concentrations of the acid, chloride salt, and oxidant also have a significant impact on silver recovery rate and silicon powder purity.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) The method provided by the present invention realizes the recycling of all components of waste photovoltaic modules, and has the characteristics of simple process, green, high efficiency, low cost and high product value;

[0038] (2) This invention realizes the recycling of tempered glass and aluminum frame, improves economic efficiency and avoids the disadvantages of high energy consumption and long process of traditional melt-recycled glass;

[0039] (3) The present invention uses thermal cutting to achieve efficient separation of battery cells from tempered glass and back sheet, avoiding the generation of organic pollutants by baking, which is energy-saving, environmentally friendly and efficient;

[0040] (4) In the method provided by the present invention, the physical and chemical properties of the material are utilized to achieve efficient recycling of tin-plated copper strips through crushing and sorting, and silver is extracted by acid dissolution and impurity elements are removed, thereby improving the silver recovery rate and the purity of silicon powder.

[0041] (5) The alloying process of this invention adopts immersion addition of silicon powder, which reduces the burning loss of silicon powder, improves the silicon recovery rate, and prepares aluminum-silicon alloy with high purity, few impurities and high added value. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of a method for recycling all components of a scrapped photovoltaic module according to an embodiment of the present invention.

[0043] Figure 2 The image shows the XRD pattern of silicon powder after acid dissolution in an embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0045] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0046] This invention provides a method for the complete recycling of waste photovoltaic modules, wherein the photovoltaic modules are polycrystalline silicon or monocrystalline silicon photovoltaic modules. The process flow diagram is shown below. Figure 1 As shown, the method first disassembles the aluminum frame and junction box of the scrapped photovoltaic module, and then uses thermal cutting at a temperature of 150-200℃ to separate the tempered glass, backsheet, and solar cells. The solar cells are crushed and sorted to obtain tin-plated copper strips and solar cell powder, respectively. Silver and silicon nitride with the antireflective layer are dissolved using nitric acid or an acid + chloride salt + oxidant system. The silver leachate is then purified and refined to obtain silver with a purity of over 99.95%, and the silicon powder has a purity of over 99.0% (XRD values ​​are shown in the image). Figure 2 As shown in the figure, silicon powder is finally alloyed with aluminum to prepare a silicon-aluminum alloy.

[0047] The implementation of the present invention will be described in detail below with reference to specific embodiments:

[0048] Example 1

[0049] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 300°C. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 720°C, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is laser-cut to separate the backsheet, glass plate, and solar cells. The cutting temperature is 150°C. The resulting glass plate is then placed at 250°C to pyrolyze the residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The battery cells were crushed to below 1.0 mm and separated by gravity to obtain tin-plated copper strips and battery cell powder. Silver was extracted and impurities removed using sulfuric acid, hydrochloric acid, and nitric acid solutions, respectively. The process parameters and effects are shown in Table 1. When sulfuric acid or hydrochloric acid was used alone as the leaching agent, silver precipitated as silver sulfate or silver chloride, resulting in low silver recovery. Simultaneously, the removal efficiency of impurities such as silicon nitride, phosphorus, and boron was poor, leading to low silicon purity. When nitric acid was used as the leaching agent, after complete silver leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.01 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.95%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.2%. The silicon powder was added to the molten aluminum using an immersion method at a melting temperature of 720℃, and AlSi50 aluminum alloy was prepared by adjusting the composition.

[0050] Table 1. Comparison of Silver Extraction and Impurity Removal Effects of Different Leaching Agents

[0051]

[0052] Example 2

[0053] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 310℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 710℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is laser-cut to separate the backsheet, glass plate, and solar cells. The cutting temperature is 160℃. The resulting glass plate is then pyrolyzed at 260℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained by gravity separation using 1.5 mol∙L⁻¹. -1Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:9 and a reaction temperature of 85℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.02 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, silver powder was obtained by reduction with hydrazine hydrate. After drying, the purity of the silver powder was 99.97%. The purity of the silicon powder after acid extraction and impurity removal was 99.1%. The silicon powder was added to the aluminum melt by immersion at a melting temperature of 710℃, and AlSi30 aluminum alloy was prepared by adjusting the composition.

[0054] Example 3

[0055] The scrapped monocrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 320℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 700℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut with a blade to separate the backsheet, glass plate, and solar cells. The cutting temperature is 170℃. The resulting glass plate is then placed at 280℃ to pyrolyze the residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained by gravity separation using 2.2 mol∙L⁻¹. -1 Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:8 and a reaction temperature of 80℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.05 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.95%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.3%. The silicon powder was added to the aluminum melt by immersion at a melting temperature of 700℃, and the composition was adjusted to prepare ADC12 aluminum alloy.

[0056] Example 4

[0057] The scrapped monocrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 330℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 690℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is laser-cut to separate the backsheet, glass plate, and solar cells. The cutting temperature is 180℃. The resulting glass plate is then pyrolyzed at 290℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained by gravity separation using 3.0 mol∙L⁻¹. -1 Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:7 and a reaction temperature of 75°C. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, maintaining the chloride ion concentration in the filtrate at 0.10 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.97%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.5%. The silicon powder was added to the molten aluminum using an immersion method at a melting temperature of 690℃, and AlSi20 aluminum alloy was prepared by adjusting the composition.

[0058] Example 5

[0059] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 350°C until the silicone rubber inside softens. The aluminum frame is then disassembled using hydraulic derivation. The disassembled aluminum frame is melted at 680°C, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut with a blade to separate the backsheet, glass plate, and solar cells. The cutting temperature is 190°C. The resulting glass plate is then pyrolyzed at 300°C to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and obtained by gravity separation of tin-plated copper strips and solar cell powder. A 4.5 mol∙L⁻¹ solution is used. -1 Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:5 and a reaction temperature of 65℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, maintaining the chloride ion concentration in the filtrate at 0.25 mol∙L⁻¹. -1After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.98%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.4%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 680℃, and the composition was adjusted to prepare A360 aluminum alloy.

[0060] Example 6

[0061] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 340℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 670℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is laser-cut to separate the backsheet, glass plate, and solar cells. The cutting temperature is 200℃. The resulting glass plate is then pyrolyzed at 285℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 5.0 mol∙L⁻¹ solution is used. -1 Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:4 and a reaction temperature of 50°C. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, maintaining the chloride ion concentration in the filtrate at 0.35 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.96%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.5%. The silicon powder was added to the aluminum melt using an immersion method at a melting temperature of 670℃, and the composition was adjusted to prepare ADC12 aluminum alloy.

[0062] Example 7

[0063] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 320℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 680℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut using wire cutting at 190℃ to separate the backsheet, glass plate, and solar cells. The resulting glass plate is then pyrolyzed at 280℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 6.0 mol∙L⁻¹ solution is used. -1Silver in the battery cells was leached using nitric acid at a solid-liquid ratio of 1:3 and a reaction temperature of 20°C. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, maintaining the chloride ion concentration in the filtrate at 0.50 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.96%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.2%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 690℃, and the composition was adjusted to prepare 4032 aluminum alloy.

[0064] Example 8

[0065] The scrapped monocrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 300℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 670℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut using wire cutting at 200℃ to separate the backsheet, glass plate, and solar cells. The resulting glass plate is then pyrolyzed at 290℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained by gravity separation using 6.0 mol∙L⁻¹. -1 Hydrochloric acid, solid-liquid ratio 1:5, hydrogen peroxide 50 g∙L -1 The silver in the battery cells was leached at a reaction temperature of 70℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.20 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.97%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.4%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 680℃, and the composition was adjusted to prepare 4032 aluminum alloy.

[0066] Example 9

[0067] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 310℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 680℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is laser-cut to separate the backsheet, glass plate, and solar cells. The cutting temperature is 190℃. The resulting glass plate is then placed at 280℃ to pyrolyze the residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained by gravity separation using 5.0 mol∙L⁻¹. -1 Hydrochloric acid, 2.0 mol∙L -1 Sodium chloride, sodium chlorate 20 g·L -1 The silver in the battery cells was leached using a solid-liquid ratio of 1:6 and a reaction temperature of 75℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.01 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.95%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.3%. The silicon powder was added to the molten aluminum using an immersion method at a melting temperature of 690℃, and AlSi30 aluminum alloy was prepared by adjusting the composition.

[0068] Example 10

[0069] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 320℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 690℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut with a blade to separate the backsheet, glass plate, and solar cells. The cutting temperature is 180℃. The resulting glass plate is then pyrolyzed at 270℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 3.0 mol∙L⁻¹ solution is used. -1 Hydrochloric acid, 5.0 mol∙L -1 Potassium chloride, sodium hypochlorite 30 g·L -1 The silver in the battery cells was leached using a solid-liquid ratio of 1:7 and a reaction temperature of 80℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.20 mol∙L⁻¹. -1After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.98%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.1%. The silicon powder was added to the aluminum melt by immersion at a melting temperature of 700℃, and the composition was adjusted to prepare ADC12 aluminum alloy.

[0070] Example 11

[0071] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 330℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivets. The disassembled aluminum frame is then melted at 720℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut with a blade to separate the backsheet, glass plate, and solar cells. The cutting temperature is 190℃. The resulting glass plate is then pyrolyzed at 280℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 2.0 mol∙L⁻¹ solution is used. -1 Sulfuric acid, 6.0 mol∙L -1 Magnesium chloride, sodium chlorate 10 g·L -1 The silver in the battery cells was leached using a solid-liquid ratio of 1:8 and a reaction temperature of 90℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.30 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.96%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.3%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 720℃, and 6063 aluminum alloy was prepared by adjusting the composition.

[0072] Example 12

[0073] The scrapped monocrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 340℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 710℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut using wire cutting to separate the backsheet, glass plate, and solar cells. The cutting temperature is 180℃. The resulting glass plate is then pyrolyzed at 260℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm, and tin-plated copper strips and solar cell powder are obtained through sieving. A 3.0 mol∙L⁻¹ solution is used. -1 Sulfuric acid, 6.0 mol∙L -1 Sodium chloride, hydrogen peroxide 40 g·L -1 The silver in the battery cells was leached using a solid-liquid ratio of 1:10 and a reaction temperature of 90℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.50 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.96%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.6%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 710℃, and 6063 aluminum alloy was prepared by adjusting the composition.

[0074] Example 13

[0075] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 350℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 720℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut using wire cutting to separate the backsheet, glass plate, and solar cells. The cutting temperature is 150℃. The resulting glass plate is then pyrolyzed at 250℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 1.0 mol∙L⁻¹ solution is used. -1 Hydrochloric acid, 3.0 mol∙L -1 Calcium chloride, sodium hypochlorite 30 g∙L -1 The silver in the battery cells was leached using a solid-liquid ratio of 1:9 and a reaction temperature of 80℃. After complete leaching, the solution was filtered, and sodium chloride was added to the filtrate to precipitate silver chloride, controlling the chloride ion concentration in the filtrate to be 0.40 mol∙L⁻¹. -1After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, silver powder was obtained by reduction with hydrazine hydrate. After drying, the purity of the silver powder was 99.95%. The purity of the silicon powder after acid extraction and impurity removal was 99.1%. The silicon powder was added to the aluminum melt by immersion at a melting temperature of 690℃, and AlSi20 aluminum alloy was prepared by adjusting the composition.

[0076] Example 14

[0077] The scrapped polycrystalline silicon photovoltaic modules are placed on a dismantling workbench. First, the junction box is removed. Then, the aluminum frame is heated to 350℃. After the silicone rubber inside the frame softens, the aluminum frame is disassembled using hydraulic derivation. The disassembled aluminum frame is then melted at 720℃, and after composition adjustment, it is recycled for high-quality preservation. The EVA layer is cut using wire cutting to separate the backsheet, glass plate, and solar cells. The cutting temperature is 150℃. The resulting glass plate is then pyrolyzed at 250℃ to remove residual EVA. Impurities on the glass surface are removed by ultrasonic cleaning, and scratches are removed by high-speed friction of polishing powder and a polishing brush on the glass surface, achieving high-value recycling of tempered glass. The solar cells are crushed to below 1.0 mm and sieved to obtain tin-plated copper strips and solar cell powder. A 1.0 mol∙L⁻¹ solution is used. -1 Sulfuric acid, 1.0-4.0 mol∙L -1 Magnesium chloride, 50 g∙L -1 Silver was leached from the battery cells using hydrogen peroxide at a solid-liquid ratio of 1:10 and a reaction temperature of 80℃. The leaching results are shown in Table 2. With increasing chloride ion concentration, both the silver leaching rate and silicon purity significantly increased. When the magnesium chloride concentration was 4.0 mol∙L⁻¹... -1 After the silver has completely leached out, filter the solution and add sodium chloride to the filtrate to precipitate the silver chloride, controlling the chloride ion concentration in the filtrate to be 0.40 mol∙L⁻¹. -1 After complete precipitation, the mixture was filtered, and ammonia was added to complex the silver with the solution to obtain a silver ammonia solution. Finally, hydrazine hydrate was used to reduce the silver to obtain silver powder, which was dried to a purity of 99.95%. The silicon powder, after acid extraction and impurity removal, had a purity of 99.5%. The silicon powder was added to the molten aluminum using an immersion process at a melting temperature of 690℃, and AlSi20 aluminum alloy was prepared by adjusting the composition.

[0078] Table 2 Comparison of silver extraction and impurity removal effects at different chloride ion concentrations

[0079]

Claims

1. A method for the complete recycling of all components of a waste photovoltaic module, characterized in that, Includes the following steps: S1: Disassembly: Disassemble the waste photovoltaic module to obtain the aluminum frame, junction box and encapsulation layer; Step S1 separates the aluminum frame by heating and softening the organic silicone in the aluminum frame and hydraulic derivetization, with a heating temperature of 300-350℃, and the separated aluminum frame is recycled for use in photovoltaic frames. S2: EVA separation: Thermal cutting of EVA is used to separate the backplane, glass plate and battery cells of the encapsulation layer; the thermal cutting in step S2 includes any one of laser cutting, wire cutting and blade cutting, with a cutting temperature of 150-200℃. The obtained glass plate is placed at 250-300℃ to pyrolyze the residual EVA, and then it is cleaned, polished and recycled. S3: Cell crushing and sorting: The cells are crushed and sorted to obtain tin-plated copper strips and cell powder; S4: Silver and Antireflection Layer Removal: The battery cell powder is placed in a leaching solution to extract silver and remove the antireflection layer, yielding a silver-containing leaching solution and silicon powder. The leaching solution comprises a mixture of acid, chloride salt, and oxidant, wherein the acid includes any one or two of hydrochloric acid and sulfuric acid, the chloride salt includes one or more of sodium chloride, potassium chloride, magnesium chloride, and calcium chloride, and the oxidant includes one or more of hydrogen peroxide, sodium chlorate, and sodium hypochlorite; the acid concentration is 1.0-6.0 mol∙L⁻¹. -1 Chloride ion concentration ≥ 6.0 mol∙L -1 The solid-liquid ratio is 1:5-1:10, and the oxidant concentration is 10.0-50.0 g∙L. -1 ; S5: Separation and purification of silver: Silver is purified by a process of chlorination precipitation-ammonia complexation-hydrazine hydrate reduction, and the purity of silver is above 99.95%; in step S5, chlorination precipitation is to control the concentration of chloride ions in the system to form silver chloride precipitate, then ammonia water is used to complex and dissolve the silver chloride to further remove impurities, and finally hydrazine hydrate reduction is used to obtain silver powder. S6: Silicon powder alloying: Silicon powder is alloyed with aluminum to prepare aluminum alloys or aluminum-silicon master alloys.

2. The method for recycling all components of a scrapped photovoltaic module as described in claim 1, characterized in that, The photovoltaic modules are silicon-based photovoltaics, including polycrystalline silicon and monocrystalline silicon photovoltaic modules.

3. The method for recycling all components of a scrapped photovoltaic module as described in claim 1, characterized in that, In step S3, the particle size of the battery cell powder is ≤1.0 mm, and the sorting method includes either gravity sorting or sieving.

4. The method for recycling all components of a scrapped photovoltaic module as described in claim 1, characterized in that, In step S5, the chloride ion concentration in the system is controlled to be 0.01 mol∙L. -1 ~0.50 mol∙L -1 .

5. The method for recycling all components of a scrapped photovoltaic module as described in claim 1, characterized in that, In step S6, the silicon powder has a purity of over 99.0%, and the alloying process uses an immersion method to add silicon powder to prevent high-temperature oxidation of the silicon powder.

6. The method for recycling all components of a scrapped photovoltaic module as described in claim 1, characterized in that, The cleaning process involves removing impurities from the glass surface using ultrasonic cleaning, followed by high-speed friction of the glass surface with polishing powder and a polishing brush to remove scratches and improve the glass's light transmittance and refractive properties.

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