Method for recycling waste photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic module recycling, in particular to a method for recycling a waste photovoltaic module, which comprises the following steps: S1, firstly, removing an aluminum frame and a junction box of the photovoltaic module through mechanical separation; s2, the light-transmitting side of the photovoltaic module faces upwards, the photovoltaic module is placed in photon sintering equipment, a xenon lamp sintering technology is used for conducting instantaneous heating on the photovoltaic module within the millisecond level range, and the EVA packaging adhesive film is promoted to be cracked at the high temperature; s3, realizing complete separation of the glass plate, the battery piece and the back plate by means of a mechanical stripping technology; s4, removing residual glue from the glass plate, the battery piece and the back plate; and S5, valuable metal in the battery piece and the welding strip is recycled step by step. Compared with the prior art, the disassembling efficiency of the photovoltaic module can be remarkably improved, and meanwhile, the integrity of a glass plate, a solar cell and a back plate after separation can be improved, so that the recovery efficiency and the recovery value of valuable components in the photovoltaic module are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic module disassembly, and in particular to a method for disassembling photovoltaic modules and recovering valuable components based on rapid pyrolysis. Background Art

[0002] Driven by the dual needs of environmental protection and resource recycling, the first generation of photovoltaic modules are gradually entering the end of their life cycle, and their proper disposal has become an environmental issue that needs to be addressed urgently. In view of the rich resource treasure trove contained in photovoltaic modules - non-ferrous metals, precious metals and high-quality ultra-white glass, etc., the scientific disassembly and efficient recycling of discarded photovoltaic modules is not only a profound practice of environmental protection responsibility, but also an important way to achieve sustainable resource utilization.

[0003] Faced with this challenge, the global scientific research community has focused on the research and development of photovoltaic module recycling and reuse technology, striving to maximize the excavation and recovery of valuable resources while protecting the ecological environment. So far, the exploration has achieved initial results, covering a variety of pre-treatment technologies such as thermal decomposition, mechanical crushing, chemical treatment, acid leaching extraction and vacuum distillation. However, each method has its inherent limitations. For example, although the mechanical treatment method is known for its disassembly efficiency, it is still insufficient in maintaining the integrity of the glass substrate and the cell, thus restricting the efficiency and quality of subsequent resource recovery.

[0004] Based on a deep insight into the current technical bottleneck, we have innovatively proposed a more advanced, fast, efficient and environmentally friendly comprehensive recycling technology solution. This solution aims to fully overcome the limitations of existing technologies, inject new vitality and impetus into the green cycle development of the photovoltaic industry by optimizing the disassembly process, improving resource separation accuracy and recycling efficiency, and become a key step in leading the industry towards a more sustainable future. Summary of the invention

[0005] The purpose of the present invention is to provide a method for recycling waste photovoltaic modules to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for recycling waste photovoltaic modules comprises the following steps:

[0008] S1. Remove the aluminum frame and junction box of the photovoltaic module by mechanical separation;

[0009] S2, placing the photovoltaic module with the light-transmitting side facing upward in a photon sintering device, and using xenon lamp sintering technology to instantaneously heat the photovoltaic module within the millisecond range, causing the EVA encapsulation film to crack at high temperature;

[0010] S3, using mechanical peeling technology to achieve complete separation of the glass plate, battery cell and backplane;

[0011] S4, remove residual glue from glass plate, battery cell and back plate;

[0012] S5. Recycle the valuable metals in battery cells and solder strips step by step.

[0013] Preferably, in step S2, the distance between the photovoltaic module and the xenon lamp is 10 mm to 100 mm.

[0014] Preferably, in step S2, the pulse energy range of the xenon lamp sintering technology is 1 J / cm 2 ~50J / cm 2 The duration of single pulse sintering is 0.1ms~5s.

[0015] Preferably, in step S2, the pulse number of the xenon lamp sintering technology is 1 to 50 times, and the pulse interval is 100 μs to 1 s.

[0016] Preferably, in step S4, the residual EVA glue on the surface of the glass plate, the battery cell and the back plate is sintered by a xenon lamp to be cracked and completely removed.

[0017] Preferably, in step S5, the silver and aluminum on the surface of the battery cell and the tin, lead and copper valuable metals in the soldering ribbon are recovered based on green solvents.

[0018] Preferably, the green solvent is a deep eutectic solvent, the main components of which are choline chloride, a hydrogen bond donor such as urea, a renewable carboxylic acid or a renewable polyol, a variable valence metal chloride, and an oxidant.

[0019] Preferably, the deep eutectic solvent components for recovering silver and aluminum on the surface of the battery cell are choline chloride: hydrogen bond donor: variable valence metal chloride, the molar ratio of choline chloride: hydrogen bond donor: variable valence metal chloride is 1:1:0.1 to 1:8:1, the reaction temperature is 60°C to 120°C, and the reaction time is 0.5h to 5h.

[0020] Preferably, the deep eutectic solvent components of the recycled solder strip surface tin, lead and copper are choline chloride: hydrogen bond donor: oxidant, the molar ratio of choline chloride: hydrogen bond donor: oxidant is 1:1:1 to 1:8:10, the reaction temperature is 60°C to 120°C, and the reaction time is 0.5h to 5h.

[0021] Compared with the prior art, the photovoltaic module rapid disassembly and recycling method based on photon sintering technology of the present invention has significant beneficial effects mainly in the following aspects:

[0022] 1. Significantly improve disassembly efficiency: By adopting xenon lamp sintering technology within the millisecond range, this method achieves instantaneous high-temperature heating of photovoltaic modules, prompting the rapid decomposition of EVA packaging film. This process greatly shortens the time required for heating and softening packaging materials in traditional disassembly methods, thereby significantly improving the overall disassembly efficiency.

[0023] 2. Maintain the integrity of component materials: Photonic sintering technology, with its precisely controlled high-temperature treatment, ensures that during the disassembly process, major components such as glass panels, cells and back panels can maintain their original physical integrity and structural strength to the maximum extent. This is not only conducive to subsequent automated separation processing, but also reduces the reduction in material value caused by physical damage during the disassembly process, making the subsequent recycling of these valuable components more efficient and valuable. Whether it is the reuse of glass panels or the recovery of valuable metal materials in cells, a higher recovery rate and purity can be achieved, thereby improving the economic and environmental benefits of the entire photovoltaic component recycling process.

[0024] 3. Environmental protection and energy saving: Compared with the traditional disassembly methods of chemical dissolution or high-temperature and long-term heating, photon sintering technology reduces energy consumption and the emission of harmful substances, reduces pollution to the environment, and meets the requirements of green and sustainable development; using green solvents as recovery media, compared with traditional chemical solvents or mechanical stripping methods, it greatly reduces the emission of harmful substances and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of the method for recycling waste photovoltaic modules. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, the present application provides a method for recycling waste photovoltaic modules, comprising the following steps S1-S5, which are specifically as follows:

[0028] S1. Remove the aluminum frame and junction box of the photovoltaic module by mechanical separation.

[0029] S2, placing the photovoltaic module with the light-transmitting side facing upward in a photon sintering device, and using xenon lamp sintering technology to instantaneously heat the photovoltaic module within the millisecond range, causing the EVA encapsulation film to crack at high temperature;

[0030] The vertical distance between the photovoltaic module and the xenon lamp light source is 10 to 50 mm, and the pulse energy range of the xenon lamp sintering technology is 1 to 50 J / cm 2 The duration of single pulse sintering is 0.1ms~5s, the number of pulses is 1~50 times, and the pulse interval is 100μs~1s.

[0031] S3. With the help of mechanical peeling technology, the back panel can be completely separated from the glass panel and the battery cells, but some battery cells still need to be manually peeled off from the glass panel for a second time;

[0032] S4. For the residual EVA glue on the glass plate, battery cell and back plate surface, the front and back sides are sintered again with a xenon lamp to decompose the residual EVA glue until it is completely removed, or wiping with an auxiliary solvent, heating and other means are used to obtain a clean glass plate, battery cell and welding strip;

[0033] S5. Recycle the valuable metals in battery cells and solder strips step by step.

[0034] (1) A deep eutectic solvent is prepared by using choline chloride and urea or ethylene glycol in a molar ratio of 1:2 to 1:8 to dissolve the aluminum electrode on the surface of the battery cell at a temperature of 95°C to 120°C for 2 to 3 hours; after removing the battery cell, a NaOH solution is slowly added to the solution with continuous stirring to control the pH value between 5.5 and 8.5 to obtain aluminum hydroxide precipitate, which is then washed with water to remove attached impurities; finally, a calcination treatment is performed as required to obtain pure aluminum oxide.

[0035] (2) preparing a mixed solution of choline chloride and water in a molar ratio of 1:4 to 1:8, and adding ferric chloride, wherein the molar ratio of choline chloride to ferric chloride is 1:0.3 to 1:1, removing the silver electrode on the surface of the battery cell at a temperature of 80°C to 95°C for 1 to 2 hours; after filtering out the battery cell, adding a large amount of deionized water to the leaching solution, causing silver chloride precipitation; and obtaining pure silver chloride solid after washing, filtering, and drying.

[0036] (3) A mixture of choline chloride and oxalic acid dihydrate in a molar ratio of 1:1 to 1:4 is prepared, and H2O2 is added, the molar ratio of choline chloride to H2O2 is 1:2 to 1:10, and the mixture is used to etch the tin-lead alloy on the surface of the solder strip at a temperature of 80°C to 95°C for 1.5 to 3 hours; after the exposed copper strip is cleaned and separated, an excess of dilute hydrochloric acid is first added to the leaching solution to produce a white lead chloride precipitate, which is filtered, washed, and dried to obtain a lead chloride solid; NaOH is added to the filtrate again to obtain a white tin hydroxide precipitate, which is filtered, washed, and dried to obtain a tin hydroxide solid.

[0037] According to reactions (1) to (3), aluminum, silver, tin and lead on the surface of the battery cell and the solder strip can be leached out respectively, and then the valuable metals can be precipitated out in the form of compounds by chemical precipitation to obtain pure valuable metal compounds. Subsequently, the corresponding metal elements can be obtained through further processing as needed.

[0038] The present application is further described in detail below in conjunction with specific embodiments. The following embodiments are only used to illustrate the present application and are not used to limit the scope of the present application.

[0039] Example 1

[0040] A method for recycling waste photovoltaic modules comprises the following steps S1-S5, which are specifically as follows:

[0041] S1. Remove the aluminum frame and junction box of the photovoltaic module by mechanical separation.

[0042] S2, placing the photovoltaic module with the light-transmitting side facing upward in a photon sintering device, and using xenon lamp sintering technology to instantaneously heat the photovoltaic module within the millisecond range, causing the EVA encapsulation film to crack at high temperature;

[0043] The vertical distance between the photovoltaic module and the xenon lamp light source is 10 mm, and the pulse energy range of the xenon lamp sintering technology is 10 J / cm 2 The duration of single pulse sintering is 0.5ms and the number of pulses is 30.

[0044] S3. With the help of mechanical peeling technology, the back panel, glass panel and battery cell can be completely separated, but some EVA glue still remains on the surface;

[0045] S4, the residual EVA glue on the surface of the glass plate, the battery cell and the back plate is subjected to xenon lamp sintering technology again on both sides, the conditions are consistent with those in step S2, and the process can be repeated multiple times, so that the residual EVA glue is cracked and completely removed, thereby obtaining the glass plate, the battery cell and the welding strip;

[0046] S5. Recycle the valuable metals in battery cells and solder strips step by step.

[0047] (1) A deep eutectic solvent is prepared by using choline chloride and ethylene glycol in a molar ratio of 1:2 to dissolve the aluminum electrode on the surface of the battery cell at a temperature of 100°C for 5 hours; after removing the battery cell, a NaOH solution is slowly added to the solution with continuous stirring to control the pH value at 8 to obtain aluminum hydroxide precipitate, which is then washed with water to remove attached impurities; finally, a calcination treatment is performed as needed to obtain pure aluminum oxide.

[0048] (2) preparing a mixed solution of choline chloride and water in a molar ratio of 1:4, and adding ferric chloride, the molar ratio of choline chloride to ferric chloride being 1:0.75, removing the silver electrode on the surface of the battery cell at a temperature of 90°C for 2 hours; after filtering out the battery cell, adding a large amount of deionized water to the leaching solution, causing silver chloride precipitation; after washing, filtering, and drying, obtaining pure silver chloride solid.

[0049] (3) A mixture of choline chloride and oxalic acid dihydrate in a molar ratio of 1:1 is prepared, and H2O2 is added, the molar ratio of the added amount of choline chloride to H2O2 is 1:2, and the tin-lead alloy on the surface of the solder strip is etched at a temperature of 90°C for 1.5 hours; after the exposed copper strip is cleaned and separated, an excess of dilute hydrochloric acid is first added to the leachate to produce a white lead chloride precipitate, and the precipitate is filtered, washed, and dried to obtain a lead chloride solid; NaOH is added to the filtrate again to obtain a white precipitate of tin hydroxide, and the precipitate is filtered, washed, and dried to obtain a tin hydroxide solid.

[0050] According to reactions (1) to (3), aluminum, silver, tin and lead on the surface of the battery cell and the solder strip can be leached out respectively, and then the valuable metals can be precipitated out in the form of compounds by chemical precipitation to obtain pure valuable metal compounds. Subsequently, the corresponding metal elements can be obtained through further processing as needed.

[0051] Embodiment 2:

[0052] A method for recycling waste photovoltaic modules comprises the following steps S1-S5, which are specifically as follows:

[0053] S1. Remove the aluminum frame and junction box of the photovoltaic module by mechanical separation.

[0054] S2, placing the photovoltaic module with the light-transmitting side facing upward in a photon sintering device, and using xenon lamp sintering technology to instantaneously heat the photovoltaic module within the millisecond range, causing the EVA encapsulation film to crack at high temperature;

[0055] The vertical distance between the photovoltaic module and the xenon lamp light source is 10 mm, and the pulse energy range of the xenon lamp sintering technology is 50 J / cm 2 The single pulse sintering lasts for 5 seconds and the number of pulses is 1.

[0056] S3. With the help of mechanical peeling technology, the back panel, glass panel and battery cell can be completely separated, but the EVA glue is carbonized and blackened;

[0057] S4. For the carbonized and blackened EVA glue on the surface of the glass plate, battery cell and back plate, soften it with alcohol, then gently wipe it off with a cloth or scraper, or heat it with a hair dryer or hot air gun to soften it and then remove it, so as to obtain a clean glass plate, battery cell and welding strip;

[0058] S5. Recycle the valuable metals in battery cells and solder strips step by step.

[0059] (1) A deep eutectic solvent is prepared by using choline chloride and ethylene glycol in a molar ratio of 1:2 to dissolve the aluminum electrode on the surface of the battery cell at a temperature of 100°C for 5 hours; after removing the battery cell, a NaOH solution is slowly added to the solution with continuous stirring to control the pH value at 6 to obtain aluminum hydroxide precipitate, which is then washed with water to remove attached impurities; finally, a calcination treatment is performed as needed to obtain pure aluminum oxide.

[0060] (2) preparing a mixed solution of choline chloride and water in a molar ratio of 1:8, and adding ferric chloride, the molar ratio of choline chloride to ferric chloride being 1:0.8, removing the silver electrode on the surface of the battery cell at a temperature of 80°C for 5 hours; after filtering out the battery cell, adding a large amount of deionized water to the leaching solution, silver chloride precipitates; after washing, filtering, and drying, a pure silver chloride solid is obtained.

[0061] (3) A mixture of choline chloride and oxalic acid dihydrate in a molar ratio of 1:1 is prepared, and H2O2 is added, the molar ratio of the added amount of choline chloride to H2O2 is 1:3, and the tin-lead alloy on the surface of the solder strip is etched at a temperature of 95°C for 1 hour; after the exposed copper strip is cleaned and separated, an excess of dilute hydrochloric acid is first added to the leaching solution to produce a white lead chloride precipitate, and the precipitate is filtered, washed, and dried to obtain a lead chloride solid; NaOH is added to the filtrate again to obtain a white precipitate of tin hydroxide, and the precipitate is filtered, washed, and dried to obtain a tin hydroxide solid.

[0062] According to reactions (1) to (3), aluminum, silver, tin and lead on the surface of the battery cell and the solder strip can be leached out respectively, and then the valuable metals can be precipitated out in the form of compounds by chemical precipitation to obtain pure valuable metal compounds. Subsequently, the corresponding metal elements can be obtained through further processing as needed.

[0063] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for recycling waste photovoltaic modules, characterized in that: The following steps are involved: S1. Remove the aluminum frame and junction box of the photovoltaic module by mechanical separation; S2, placing the photovoltaic module with the light-transmitting side facing upward in a photon sintering device, and using xenon lamp sintering technology to instantaneously heat the photovoltaic module within the millisecond range, causing the EVA encapsulation film to crack at high temperature; S3, using mechanical peeling technology to achieve complete separation of the glass plate, battery cell and backplane; S4, remove residual glue from glass plate, battery cell and back plate; S5. Recycle the valuable metals in battery cells and solder strips step by step.

2. A method for recycling waste photovoltaic modules according to claim 1, characterized in that: In step S2, the distance between the photovoltaic module and the xenon lamp is 10 mm to 100 mm.

3. A method for recycling waste photovoltaic modules according to claim 1, characterized in that: In step S2, the pulse energy range of the xenon lamp sintering technology is 1 J / cm 2 ~50J / cm 2 The duration of single pulse sintering is 0.1ms~5s.

4. A method for recycling waste photovoltaic modules according to claim 1, characterized in that: In the step S2, the pulse number of the xenon lamp sintering technology is 1 to 50 times, and the pulse interval is 100 μs to 1 s.

5. A method for recycling waste photovoltaic modules according to claim 1, characterized in that: In step S4, the residual EVA glue on the surface of the glass plate, the battery cell and the back plate is sintered by a xenon lamp to be cracked and completely removed.

6. A method for recycling waste photovoltaic modules according to claim 1, characterized in that: In the step S5, the silver and aluminum on the surface of the battery cell and the tin, lead and copper valuable metals in the soldering ribbon are recovered based on the green solvent.

7. The green solvent for recovering valuable metals according to claim 6, characterized in that: The green solvent is a deep eutectic solvent, and its main components are choline chloride, a hydrogen bond donor such as urea, a renewable carboxylic acid or a renewable polyol, a variable valence metal chloride, an oxidant and the like.

8. The deep eutectic solvent according to claim 7, characterized in that The deep eutectic solvent components for recovering silver and aluminum on the surface of the battery cell are choline chloride: hydrogen bond donor: variable valence metal chloride, the molar ratio of choline chloride: hydrogen bond donor: variable valence metal chloride is 1:1:0.1-1:8:1, the reaction temperature is 60°C-120°C, and the reaction time is 0.5h-5h.

9. The deep eutectic solvent according to claim 7, characterized in that The deep eutectic solvent components for recovering tin, lead and copper on the surface of the solder strip are choline chloride: hydrogen bond donor: oxidant, the molar ratio of choline chloride: hydrogen bond donor: oxidant is 1:1:1-1:8:10, the reaction temperature is 60°C-120°C, and the reaction time is 0.5h-5h.

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