Method for separating photovoltaic module by using external field coupling technology

Abstract

The invention relates to a method for separating photovoltaic modules by adopting an external field coupling technology, and belongs to the field of organic chemical industry and the field of efficient cyclic utilization of secondary resources. The method comprises the following steps: placing the retired photovoltaic module and an organic solvent in a dynamic fluid circulation system for layering treatment, wherein a physical field is arranged outside the dynamic fluid circulation system; the dynamic fluid circulation system controls the organic solvent to circularly flow on the surface of the decommissioned photovoltaic module and complete layering of the decommissioned photovoltaic module under the action of an external physical field, and then waste liquid and solids are obtained through solid-liquid separation; the solid comprises glass, a crystalline silicon cell and a back plate; the external physical field comprises at least one of an ultrasonic field, a microwave field and an electromagnetic field. According to the method, external physical fields such as ultrasonic waves, microwaves or electromagnetic fields are introduced to cooperate with the chemical action of the organic solvent and the dynamic fluid circulation system, so that the stripping efficiency of the EVA packaging layer and the photovoltaic module is improved, complete recovery of glass, crystalline silicon battery pieces and back plates can be ensured, and meanwhile, the method is low in energy consumption and high in efficiency.

Description

Technical Field

[0001] The present invention relates to a method for separating photovoltaic modules by using external field coupling technology, belonging to the fields of organic chemical industry and efficient recycling of secondary resources. Background Art

[0002] In recent years, photovoltaic power generation technology has developed rapidly worldwide and has become an important pillar for addressing climate change and energy transformation. With technological progress and policy promotion, large-scale deployment of photovoltaic modules has covered many countries and regions. However, the designed lifespan of photovoltaic modules is usually 25 - 30 years. As the early installed modules gradually enter the retirement period, the quantity of global photovoltaic waste is increasing exponentially. Therefore, how to efficiently, safely, and environmentally recycle retired photovoltaic modules has become an issue that must be addressed for the sustainable development of the photovoltaic industry.

[0003] Currently, the recycling methods for waste photovoltaic modules mainly include mechanical crushing, pyrolysis, and chemical swelling methods. The mechanical crushing method is simple to operate, but has problems such as uneven crushing degree, low recycling purity, and easy damage to silicon wafers and glass. The pyrolysis method removes EVA by pyrolysis at high temperature (usually >500°C), but has high energy consumption, high equipment cost, and is prone to causing thermal cracks in silicon wafers and heavy metal volatilization pollution. The chemical swelling method dissolves EVA with organic solvents, has certain selectivity, but generally has defects such as slow reaction rate, large solvent consumption, and difficult residue removal.

[0004] However, there is currently a lack of a recycling process that integrates the coupling of external fields and solvent methods, and the related devices and control strategies are not yet mature. Therefore, there is an urgent need to develop a technology for separating photovoltaic modules by enhancing solvent with external field coupling that has a reasonable structure, high energy efficiency, environmental friendliness, and is suitable for large-scale treatment to address the deficiencies in the existing technology and promote the high-value utilization of the resource recycling of photovoltaic modules. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a method for separating photovoltaic modules by using external field coupling technology. The present invention improves the peeling efficiency of the EVA encapsulation layer and the photovoltaic module by introducing external physical fields such as ultrasonic waves, microwaves, or electromagnetic fields and cooperating with the chemical action of organic solvents and the dynamic fluid circulation system, and can also ensure the complete recycling of glass, crystalline silicon solar cells, and backsheets. At the same time, the method of the present invention has a short time consumption, low energy consumption, and high efficiency.

[0006] To achieve the above purpose, the first aspect of the present invention is to provide a method for separating photovoltaic modules by using external field coupling technology, the method comprising:

[0007] The retired photovoltaic modules and organic solvents are placed in a dynamic fluid circulation system for delamination treatment. A physical field is provided outside the dynamic fluid circulation system. The dynamic fluid circulation system controls the organic solvents to circulate on the surface of the retired photovoltaic modules and complete the delamination of the retired photovoltaic modules under the action of the external physical field, and then liquid-solid separation is carried out to obtain waste liquid and solid substances. The solid substances contain glass, crystalline silicon cells and backsheets.

[0008] The external physical field includes at least one of an ultrasonic field, a microwave field and an electromagnetic field.

[0009] The innovation of the present invention lies in the first synergistic coupling of external physical fields such as ultrasonic waves, microwaves or electromagnetic fields, organic solvent separation and a dynamic fluid circulation system, which significantly improves the swelling and peeling efficiency of the EVA encapsulation layer and breaks through the problems of slow treatment and low efficiency of the traditional solvent method.

[0010] When the external physical field is an ultrasonic field, the chain segment breakage and interface perturbation of the EVA encapsulation layer are realized through the liquid-phase cavitation effect, which significantly accelerates the solvent penetration and EVA separation process. This solution is suitable for relatively thick or highly cross-linked EVA layers, and can achieve a peeling effect similar to that of traditional high-temperature dissolution at a lower temperature. At the same time, it protects the silicon wafer and glass materials from thermal damage. The operation using the ultrasonic field is simple and has strong versatility, which is convenient for industrial promotion.

[0011] When the external physical field is a microwave field, non-contact directional heating is used to promote the local swelling of EVA in the reaction system to achieve rapid and uniform heating. The volume heating mechanism of microwaves can significantly reduce the temperature control response time and improve the thermal energy utilization rate. This solution is suitable for the processing scenarios of components with uneven EVA layer thickness and relatively tight edge encapsulation, and has the advantages of uniform heating, low energy consumption and high efficiency.

[0012] When the external physical field is an electromagnetic field, the ordered orientation of polar molecules can be enhanced, the directional penetration of polar solvent molecules can be accelerated, the depolymerization energy barrier of EVA chain segments can be reduced, molecular relaxation can be promoted, and the microscopic distribution of the solvent can be controlled to improve the uniformity and thoroughness of peeling.

[0013] Furthermore, a dynamic fluid circulation system device is adopted to ensure the uniform flow of organic solvents on the surface of the photovoltaic modules, which can avoid solvent retention or insufficient local swelling, accelerate the solvent penetration, and improve the EVA swelling rate.

[0014] The present invention realizes a green separation process with low energy consumption and high efficiency through the synergistic action of external field effects, chemical swelling and dynamic fluid circulation, and can also maintain the complete recovery of glass, silicon wafers and backsheets.

[0015] The EVA adhesive film in the crystalline silicon photovoltaic module is an organic polymer material, and the side chain is a group containing an ester group, and the molecular formula is

[0016]

[0017] As a preferred solution, the conditions of the external physical field are selected from at least one of the following conditions:

[0018] When the external physical field is an ultrasonic field, the frequency of the ultrasonic wave is 20 - 40 kHz, and the power is 200 - 500 W;

[0019] When the external physical field is a microwave field, the frequency of the microwave is 2 - 3 GHz, and the power is 500 - 700 W;

[0020] When the external physical field is an electromagnetic field, the magnetic field strength is 0.05 - 0.3 T.

[0021] It should be noted that the present invention has no special requirements for the placement position of the ultrasonic transducer that provides the ultrasonic field, and those known in the art can be used. As a preferred solution, the ultrasonic transducer is placed at the bottom or side wall of the reaction vessel.

[0022] As a preferred solution, the external physical field is a microwave field and / or an electromagnetic field. More preferably, it is an electromagnetic field.

[0023] As a preferred solution, the organic solvent is a polar solvent.

[0024] As a more preferred solution, the organic solvent is N - methylpyrrolidone and / or diethylene glycol butyl ether. More preferably, it is diethylene glycol butyl ether. The inventors found that when the organic solvent is N - methylpyrrolidone and / or diethylene glycol butyl ether, the swelling of EVA will be accelerated. When the organic solvent is diethylene glycol butyl ether, the swelling of EVA is more rapid, and it will not affect the integrity of glass, crystalline silicon solar cells and backsheets while having a fast swelling rate.

[0025] As a preferred solution, the delamination treatment includes two - stage programmed temperature rising, and the two - stage programmed temperature rising includes a pre - delamination stage and a complete delamination stage;

[0026] The temperature of the pre - delamination stage is 70 - 90 °C, and the time is 3 - 8 min;

[0027] The temperature of the complete delamination stage is 110 - 140 °C, and the time is 8 - 18 min.

[0028] The inventors found that the pre - delamination stage is used for the swelling of EVA to improve the solvent penetration ability, and then the temperature is raised to ensure uniform separation of the encapsulation layer. And because the temperature of the delamination treatment is a thermal cycling system, it can ensure the temperature uniformity of the whole reaction process, effectively avoid damage to the glass and silicon wafers caused by local overheating, and can improve the integrity and purity of the recycled materials.

[0029] As a preferred solution, the instrument for completing the programmed temperature rise is a programmable electronic thermostat. Through the programmable electronic thermostat, the temperature field is precisely controlled. Combining real-time temperature monitoring and feedback regulation, through dynamic temperature field regulation, while optimizing the heat transfer efficiency, the energy consumption is reduced, and the efficient separation of photovoltaic modules is ensured.

[0030] As a preferred solution, the liquid-solid ratio of the hierarchical treatment is 5-20 mL: 1 g.

[0031] As a preferred solution, the method further includes: distilling and recovering the waste liquid. Through the distillation method, the loss of organic solvents can be reduced, and the waste liquid discharge can be reduced. During the treatment process, the organic solvents are recovered through a condensing device and can be reused after distillation, improving the utilization rate of organic solvents and reducing the operating cost. Compared with the traditional chemical swelling method, this solution reduces the dependence on highly toxic solvents, reduces the environmental pollution risk, and improves the sustainability and economy of the photovoltaic module recycling process.

[0032] As a preferred solution, the dynamic fluid circulation system includes a circulation pump and a solvent injection device.

[0033] As a preferred solution, the nozzle of the solvent injection device is porous.

[0034] As a preferred solution, the flow rate of the circulation pump is 15-30 mL / min.

[0035] Compared with the prior art, the present invention has at least the following advantages:

[0036] (1) The method provided by the present invention is an integrated separation system that integrates temperature control, external field action, solvent circulation, solid-liquid separation and recovery, realizing multi-stage temperature control and closed-loop utilization of resources; while reducing energy consumption and treatment time, it effectively protects the integrity and purity of high-value materials such as glass and silicon wafers; in addition, the technical process parameters are adjustable, suitable for different structures and types of photovoltaic modules, and have good adaptability and industrial application prospects.

[0037] (2) By introducing external physical fields such as ultrasonic waves, microwaves or electromagnetic fields, and synergistically coupling with the solvent action and the dynamic fluid circulation system, the activity of solvent molecules and the movement of EVA chain segments are significantly enhanced, enabling the EVA encapsulation layer to rapidly swell and break. Compared with the traditional chemical swelling method, the reaction time is shortened by 30%-50%, greatly improving the overall treatment efficiency.

[0038] (3) The present invention can achieve effective separation at medium and low temperatures (100-140 °C), replacing the high-temperature incineration required by the traditional pyrolysis method, and reducing the total system energy consumption by about 40%. At the same time, the organic solvents are distilled and recovered, effectively reducing the consumption of organic solvents and the waste liquid discharge, improving the environmental protection performance, and conforming to the concept of green manufacturing.

[0039] (4) The present invention avoids problems such as silicon wafer fragmentation and glass scratching caused by high temperature or mechanical shock, realizes the removal of the encapsulation layer under mild conditions, maximally retains the structure and performance of high-value materials such as glass, silicon wafers, and metal electrodes in the components, facilitates subsequent reuse or remanufacturing, and the material recovery integrity rate can reach over 95%.

[0040] (5) The method provided by the present invention adopts combined control such as external field action, dynamic fluid circulation, and temperature control by a programmable electronic thermostat, can adapt to photovoltaic modules with different encapsulation thicknesses, crosslinking degrees, and structural forms, has the characteristics of strong versatility, high batch processing ability, and high automation degree, and is easy to be integrated into the existing industrial recycling production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a device diagram of the method for separating photovoltaic modules using the external field coupling technology adopted by the present invention;

[0042] Figure 2 is a process flow diagram of the separation of retired photovoltaic modules in Example 1;

[0043] Figure 3 is an XRD diagram of the glass separated in Example 1;

[0044] Figure 4 is an XRD diagram of the crystalline silicon cell separated in Example 1;

[0045] Figure 5 is a TGA diagram of the original EVA film in the retired photovoltaic module; from the results in the figure, the proportion of vinyl acetate (VA) in EVA can be calculated to be about 26%, showing strong "polarity affinity" characteristics in terms of solvent swelling.

[0046] Figure 6 is a display diagram of the swelling degree (ultra-depth of field microscope) of the original EVA film in the retired photovoltaic module, the EVA film separated in Example 1, and the EVA film separated in Example 5. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] In the ranges disclosed herein, the endpoints and any value are not limited to the exact range or value, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0048] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative efforts still fall within the protection scope of the present invention.

[0049] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0050] Example 1

[0051] After cleaning a small sample of retired crystalline silicon photovoltaic module with a size of 2 cm × 2 cm, it is placed in a solvent-resistant reaction tank, and 50 mL of diethylene glycol butyl ether (BDG) solvent with a purity of 99% is added. The ultrasonic transducer set at the bottom is started, the frequency is set to 28 kHz, and the power is 300 W. A continuously flowing solvent flow field is formed through a circulation pump, the flow rate is controlled at 20 mL / min, and the recycled organic solvent is sprayed onto the surface of the retired photovoltaic module through a spraying device with a porous nozzle to ensure uniform distribution of the solvent and prevent local solvent retention or flow dead zones, completing the delamination of the retired photovoltaic module. After solid-liquid separation, waste liquid and solid substances are obtained;

[0052] The liquid-solid ratio for delamination treatment is 10 mL:1 g; the delamination treatment includes two-stage programmed temperature rise, and the two-stage programmed temperature rise includes a pre-delamination stage and a complete delamination stage; a programmable electronic temperature controller is used for temperature control. The temperature in the pre-delamination stage is 85 °C and the time is 5 min; the temperature in the complete delamination stage is 135 °C and the time is 15 min.

[0053] During the experiment, the EVA layer quickly foamed and swelled and detached, and no residue was seen on the surface of the module. Moreover, the backplane and the silicon wafer structure of the crystalline silicon cell were intact without damage, and the recovery rate of the glass was 100%.

[0054] The waste liquid is distilled and recovered, and the recovery rate is 95%.

[0055] Figure 3 is the XRD pattern of the glass separated in Example 1; it can be seen from the figure that the composition of the glass is amorphous SiO2.

[0056] Figure 4 is the XRD pattern of the crystalline silicon cell separated in Example 1; it can be seen from the figure that the main components in the crystalline silicon cell are elemental Si and a small amount of Al.

[0057] Example 2

[0058] After cleaning a small sample of retired crystalline silicon photovoltaic modules with dimensions of 2 cm × 2 cm, place it in a solvent-resistant reaction tank and add 50 mL of diethylene glycol butyl ether (BDG) solvent with a purity of 99%. Start the microwave radiation module, set the operating frequency of the microwave source to 2.45 GHz and the power to 600 W, and form a continuously flowing solvent flow field through a circulation pump. Control the flow rate at 20 mL / min, and spray the circulating organic solvent onto the surface of the retired photovoltaic modules through a spraying device with a perforated nozzle to ensure uniform distribution of the solvent and prevent local solvent retention or flow dead zones. Complete the delamination of the retired photovoltaic modules, and obtain waste liquid and solids through solid-liquid separation;

[0059] The liquid-solid ratio for delamination treatment is 10 mL:1 g; the delamination treatment includes two-stage programmed temperature rise, and the two-stage programmed temperature rise includes a pre-delamination stage and a complete delamination stage; a programmable electronic temperature controller is used for temperature control. The temperature in the pre-delamination stage is 90 °C and the time is 8 min; the temperature in the complete delamination stage is 120 °C and the time is 18 min.

[0060] During the experiment, the EVA layer quickly foamed and swelled and detached, and no residue was seen on the surface of the module. Moreover, the backplane and the silicon wafer structure of the crystalline silicon cell were intact and without damage, and the recovery rate of the glass was 100%.

[0061] Distill and recover the waste liquid, and the recovery rate is 94%.

[0062] Example 3

[0063] After cleaning a small sample of retired crystalline silicon photovoltaic modules with dimensions of 2 cm × 2 cm, place it in a solvent-resistant reaction tank and add 50 mL of diethylene glycol butyl ether (BDG) solvent with a purity of 99%. Start the electromagnetic field module, set the magnetic field strength of the electromagnetic field to 0.1 T, and form a continuously flowing solvent flow field through a circulation pump. Control the flow rate at 20 mL / min, and spray the circulating organic solvent onto the surface of the retired photovoltaic modules through a spraying device with a perforated nozzle to ensure uniform distribution of the solvent and prevent local solvent retention or flow dead zones. Complete the delamination of the retired photovoltaic modules, and obtain waste liquid and solids through solid-liquid separation;

[0064] The liquid-solid ratio for delamination treatment is 10 mL:1 g; the delamination treatment includes two-stage programmed temperature rise, and the two-stage programmed temperature rise includes a pre-delamination stage and a complete delamination stage; a programmable electronic temperature controller is used for temperature control. The temperature in the pre-delamination stage is 90 °C and the time is 3 min; the temperature in the complete delamination stage is 120 °C and the time is 10 min.

[0065] During the experiment, the EVA layer quickly foamed and swelled and detached, and no residue was seen on the surface of the module. Moreover, the backplane and the silicon wafer structure of the crystalline silicon cell were intact and without damage, and the recovery rate of the glass was 100%.

[0066] The waste liquid is distilled and recovered, and the recovery rate is 94%.

[0067] Example 4

[0068] After cleaning a small sample of retired crystalline silicon photovoltaic module with a size of 2 cm × 2 cm, it is placed in a solvent-resistant reaction tank, and 50 mL of N-methylpyrrolidone (NMP) solvent with a purity of 99% is added. The ultrasonic transducer set at the bottom is started, the frequency is set to 28 kHz, and the power is 300 W. And a continuous flowing solvent flow field is formed through a circulation pump, the flow rate is set to 20 mL / min, and the recycled organic solvent (NMP) is sprayed onto the surface of the retired photovoltaic module through a spraying device with a porous nozzle to ensure uniform distribution of the solvent and prevent local solvent retention or flow dead zones to enhance the contact between the solvent and the EVA layer.

[0069] The liquid-solid ratio for the layering treatment is 10 mL:1 g; the layering treatment includes two-stage programmed temperature rise, and the two-stage programmed temperature rise includes a pre-layering stage and a complete layering stage; a programmable electronic temperature controller is used for temperature control. The temperature in the pre-layering stage is 85 °C and the time is 5 min; the temperature in the complete layering stage is 135 °C and the time is 15 min.

[0070] During the experiment, foaming and swelling phenomena began to appear in the EVA encapsulation layer, but the reaction rate was slow, and there were still colloidal substances that had not detached remaining at the edges of the module and in the crosslinking-dense areas. Under the same reaction time as in Example 1, after the treatment, the glass and silicon wafer could be completely taken out only with the assistance of tweezers, and there was slight residual glue on the surface of the silicon wafer, which required additional cleaning.

[0071] The backplane and the silicon wafer structure of the crystalline silicon cell are basically intact, and the recovery rate of the glass is 95%.

[0072] The waste liquid generated during the treatment is recovered by vacuum distillation. The recovery rate of N-methylpyrrolidone is about 85%, slightly lower than that of diethylene glycol butyl ether, mainly because its volatility is slightly higher under high-temperature conditions and part of it is lost in the gas phase.

[0073] In summary, compared with the diethylene glycol butyl ether system, N-methylpyrrolidone is slightly inferior in terms of the EVA swelling rate, stripping thoroughness, and solvent recovery performance. Under the same treatment time, there will be slight residues in the N-methylpyrrolidone system, which requires additional cleaning.

[0074] Figure 6 It is a diagram showing the swelling degree (ultra-depth-of-field microscope) of the original EVA film in the retired photovoltaic module, the EVA film separated in Example 1, and the EVA film separated in Example 5. It can be seen from the figure that the swelling degree of EVA is greater when diethylene glycol butyl ether is used as the organic solvent.

[0075] Comparative Example 1

[0076] After cleaning a small sample of retired crystalline silicon photovoltaic modules with dimensions of 2 cm × 2 cm, it was placed in a solvent-resistant reaction tank, and 50 mL of diethylene glycol butyl ether (BDG) solvent with a purity of 99% was added. The ultrasonic transducer set at the bottom was not started, the frequency was set to 0 kHz, the power was 0 W, and a continuous flowing solvent flow field was formed through a circulation pump. The flow rate was controlled at 20 mL / min, and the recycled organic solvent was sprayed onto the surface of the retired photovoltaic modules through a spraying device with a perforated nozzle to ensure uniform distribution of the solvent and prevent local solvent retention or flow dead zones. The delamination of the retired photovoltaic modules was completed, and waste liquid and solids were obtained through solid-liquid separation;

[0077] The liquid-solid ratio for delamination treatment was 10 mL:1 g; the delamination treatment included two-stage programmed temperature rise, and the two-stage programmed temperature rise included a pre-delamination stage and a complete delamination stage; a programmable electronic temperature controller was used for temperature control. The temperature in the pre-delamination stage was 85 °C and the time was 5 min; the temperature in the complete delamination stage was 135 °C and the time was 15 min.

[0078] Under this condition, the EVA encapsulation layer slowly foamed and some areas swelled. Under the same reaction time as in Example 1, the overall peeling rate was significantly lower than that in Example 1. Especially at the edges and structure overlapping areas of the module, the EVA peeling was incomplete and there was visible residual adhesive film. After physical peeling, only part of the encapsulation material could be removed, and additional tools were needed for auxiliary operation, and there was a small amount of adhesion residue on the surface of the silicon wafer, increasing the workload of post-treatment.

[0079] The backplane and the silicon wafer structure of the crystalline silicon cell were basically intact, and the recovery rate of the glass was 90%.

[0080] The waste liquid was distilled and recovered, and the recovery rate was 95%.

[0081] In summary, this comparative example shows that when no external physical field is introduced, both the swelling rate and peeling integrity of EVA decrease significantly, indicating that the auxiliary effect of the external physical field has significant advantages in improving separation efficiency, shortening treatment time, and protecting recycled materials.

[0082] Comparative Example 2

[0083] After cleaning a small sample of retired crystalline silicon photovoltaic modules with dimensions of 2 cm × 2 cm, it was placed in a solvent-resistant reaction tank, and 50 mL of diethylene glycol butyl ether (BDG) solvent with a purity of 99% was added. The ultrasonic transducer set at the bottom was started, the frequency was set to 28 kHz, the power was 300 W, and the circulation pump was turned off to make the solution in a static state (flow rate was 0 mL / min). The delamination of the retired photovoltaic modules was completed, and waste liquid and solids were obtained through solid-liquid separation;

[0084] The liquid-solid ratio for the hierarchical treatment is 10 mL:1 g; the hierarchical treatment includes two-stage programmed temperature rise, and the two-stage programmed temperature rise includes a pre-stratification stage and a complete stratification stage; a programmable electronic temperature controller is used for temperature control, the temperature in the pre-stratification stage is 85 °C, and the time is 5 min; the temperature in the complete stratification stage is 135 °C, and the time is 15 min.

[0085] During the experiment, the EVA encapsulation layer began to foam and expand under the action of ultrasound. However, due to the lack of fluid disturbance and solvent renewal mechanism, the solvent was locally saturated in some areas, and the reaction rate decreased. Especially in the edge, corner and back areas of the sample, the EVA was not completely peeled off or had strong adhesion, resulting in local residue.

[0086] Although the separation of glass, silicon wafers and solar cells can be achieved after treatment, in the case of the same reaction time as in Example 1, this comparative example still requires the use of tools for auxiliary peeling. There are residual EVA films or micro-particles on the surface of the silicon wafers, which affect subsequent cleaning and reuse. The recovery integrity is slightly lower than that of the experimental group with a flow field. Some reaction products are enriched in the waste liquid, reducing the cleanliness of the recycled waste solvent, and the recovery rate is about 90%.

[0087] In summary, the results of this comparative example show that under the condition of static solvent, even in the presence of an ultrasonic field, it is still difficult to achieve efficient and uniform EVA peeling. The lack of circulating flow will lead to the formation of local concentration differences and stagnant zones, affecting the swelling mass transfer process, thereby reducing the overall separation efficiency and material recovery quality. It shows that establishing a dynamic flow field plays an important role in improving the swelling uniformity and peeling thoroughness.

[0088] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for separating photovoltaic modules using external field coupling technology, characterized in that: The retired photovoltaic components and organic solvents are placed in a dynamic fluid circulation system for stratification treatment, wherein a physical field is provided outside the dynamic fluid circulation system; the dynamic fluid circulation system controls the organic solvent to circulate on the surface of the retired photovoltaic components and completes the stratification of the retired photovoltaic components under the action of the external physical field, and then obtains waste liquid and solids through solid-liquid separation; the solids contain glass, crystalline silicon cells and backplanes; The external physical field includes at least one of an ultrasonic field, a microwave field and an electromagnetic field.

2. A method for separating photovoltaic modules using external field coupling technology according to claim 1, characterized in that: The condition of the external physical field is selected from at least one of the following conditions: When the external physical field is an ultrasonic field, the frequency of the ultrasound is 20 to 40 kHz and the power is 200 to 500 W; When the external physical field is a microwave field, the frequency of the microwave is 2 to 3 GHz, and the power is 500 to 700 W; When the external physical field is an electromagnetic field, the magnetic field strength is 0.05-0.3T.

3. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The external physical field is a microwave field and / or an electromagnetic field.

4. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The organic solvent is a polar solvent.

5. The method for separating photovoltaic modules using external field coupling technology according to claim 4, characterized in that: The organic solvent is N-methylpyrrolidone and / or diethylene glycol butyl ether.

6. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The stratification process includes two stages of programmed temperature rise, wherein the two stages of programmed temperature rise include a pre-stratification stage and a complete stratification stage; The temperature of the pre-stratification stage is 70-90°C and the time is 3-8 minutes; The temperature of the complete stratification stage is 110-140° C., and the time is 8-18 minutes.

7. A method for separating photovoltaic modules using external field coupling technology according to claim 6, characterized in that: The instrument for completing the programmed temperature increase is a programmable electronic temperature controller.

8. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The liquid-to-solid ratio of the layered treatment is 5-20 mL:1 g.

9. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The method also includes: distilling and recovering the waste liquid.

10. A method for separating photovoltaic modules using external field coupling technology according to claim 1 or 2, characterized in that: The dynamic fluid circulation system comprises a circulation pump and a solvent injection device.

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