Recycling method of photovoltaic module

Abstract

The invention discloses a recovery method of a photovoltaic module, the photovoltaic module comprises an organic wrapping layer, glass, a frame and a junction box, the recovery method comprises the following steps: identifying the size of the frame and positioning the frame; positioning the junction box; dismantling the junction box to form a first dismantling part comprising a frame, glass and an organic wrapping layer; dismantling the frame to form a second dismantling part comprising glass and an organic wrapping layer; removing the glass by using an obtuse-angle milling cutter to obtain an organic wrapping layer; performing anaerobic low-temperature pyrolysis on the organic wrapping layer to obtain a gaseous component and a solid component; condensing or carrying out heat exchange cooling on the gaseous component to obtain a liquid component; carrying out heat exchange and cooling on solid components; and respectively collecting the gaseous component, the liquid component and the solid component according to the properties. Therefore, the recovery speed of the photovoltaic module can be increased, the recovery rate of each component in the photovoltaic module is improved, zero emission is realized, and the device has certain popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic cell assemblies, and in particular to a method for recycling photovoltaic assemblies. Background Art

[0002] Resource recycling is an important means to achieve carbon emission reduction. Against the backdrop of carbon peak and carbon neutrality, the country has introduced various policies to include the secondary utilization of photovoltaic modules and power batteries in the country's key development direction. Based on the dual carbon goals and the scientific and technological innovation plan in the energy field, the project focuses on the recycling and recycling technology of photovoltaic modules and power batteries, and breaks through the on-site disassembly and recycling technology of photovoltaic modules and the key technologies and equipment for the safe cascade utilization of power batteries. It focuses on solving the on-site low-cost disassembly and harmless recycling technology of photovoltaic modules, the secondary safety utilization of power batteries and AI intelligent detection and monitoring technology, as well as the development of green packaging materials, to achieve green manufacturing and harmless recycling of photovoltaic modules from the source of the product.

[0003] Photovoltaic modules are devices that can convert solar energy into electrical energy. Photovoltaic modules include frames, junction boxes, and stacked from bottom to top, backplanes (or glass substrates), organic adhesive layers (EVA or POE, etc.), cell layers, encapsulation films (EVA or POE, etc.), and glass substrates. Among them, the silicon, aluminum, silver, copper and other component materials in the glass substrate, backplane and cell layers can be recycled and reused.

[0004] At present, when recycling photovoltaic modules, one method is to use an incinerator to burn the crushed photovoltaic modules, so as to separate and recycle the cells, glass, and welding strips; the other method is to place the photovoltaic modules in a container containing an inorganic acid or organic acid solution to dissolve the organic adhesive film in the photovoltaic modules, so as to separate the cells and glass for recycling. The products obtained by using an incinerator are crushed glass and broken cells, which are difficult to screen and separate, wasting a lot of manpower and material costs, and there is a large loss of materials during separation, which cannot fully recycle valuable materials; the recycling cycle is long when using a container containing an acid solution, which takes more than a week, and it is difficult to treat the waste liquid in the later stage.

[0005] Therefore, how to increase the recycling speed and improve the recovery rate of each component in the photovoltaic module should be the focus of technical personnel in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a method for recycling photovoltaic modules to accelerate the recycling speed of photovoltaic modules and improve the recycling rate of each component in the photovoltaic modules. The photovoltaic module includes an organic wrapping layer, glass, a frame and a junction box. The recycling method includes the following steps:

[0007] Identify border size and position border;

[0008] Locate the junction box;

[0009] The junction box is removed to form a first disassembled component including a frame, glass and an organic wrapping layer;

[0010] Removing the frame to form a second disassembled component including glass and an organic encapsulation layer;

[0011] The glass was removed using a blunt-angle milling cutter to obtain the organic encapsulation layer;

[0012] The organic coating layer is pyrolyzed at low temperature without oxygen to obtain gaseous components and solid components;

[0013] Condensation or heat exchange cooling of gaseous components to obtain liquid components;

[0014] Cooling of solid components by heat exchange;

[0015] Collect gaseous components, liquid components and solid components separately according to their properties.

[0016] Preferably, before disassembling the glass with the blunt-angle milling cutter, the second disassembling component is preheated.

[0017] Preferably, the glass is broken after preheating the second disassembling component.

[0018] Preferably, before the organic sheath is pyrolyzed at low temperature without oxygen, the organic sheath is crushed to obtain organic sheath fragments.

[0019] Preferably, the size of the organic coating fragments is less than 5 cm x 5 cm.

[0020] Preferably, when the organic coating layer is pyrolyzed at low temperature without oxygen, the temperature range of the pyrolysis is between 300 and 450°C.

[0021] Furthermore, the liquid component is bio-oil.

[0022] Furthermore, the solid components include carbon black, silicon cells, metals and residual glass.

[0023] Preferably, a linear screen is used to screen the solid component to obtain carbon black and a second solid component including silicon cells, metals and residual glass.

[0024] Preferably, the second solid component is sieved with a specific gravity sieve to obtain a silicon cell.

[0025] Preferably, eddy current or electrostatic separation is used to separate the second solid component to obtain metal and residual glass.

[0026] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are:

[0027] The present invention adopts a combination of mechanical disassembly and oxygen-free low-temperature pyrolysis to fully recover the components in the photovoltaic modules, and designs corresponding recycling methods for each component. The recovery rate of each component is significantly improved, and the waste of organic components such as packaging films in traditional recycling methods is avoided. The tediousness of recycling or extracting various inorganic components is also avoided, and the recovery speed is significantly improved. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0029] The present invention provides a method for recycling a photovoltaic module, wherein the photovoltaic module comprises an organic wrapping layer, glass, a frame and a junction box. The recycling method comprises the following steps:

[0030] Identify border size and position border;

[0031] Locate the junction box;

[0032] The junction box is removed to form a first disassembled component including a frame, glass and an organic wrapping layer;

[0033] Removing the frame to form a second disassembled component including glass and an organic encapsulation layer;

[0034] The glass was removed using a blunt-angle milling cutter to obtain the organic encapsulation layer;

[0035] The organic coating layer is pyrolyzed at low temperature without oxygen to obtain gaseous components and solid components;

[0036] Condensation or heat exchange cooling of gaseous components to obtain liquid components;

[0037] Cooling of solid components by heat exchange;

[0038] Collect gaseous components, liquid components and solid components separately according to their properties.

[0039] In some embodiments, a visual recognition system is used to automatically identify the frame size, position the frame, and position the junction box. The size automatically recognized by the visual recognition system is greater than 1950x992mm (LxW), which can achieve accurate positioning of the junction box, intelligent grasping and removal, and the removed junction box is transferred to the junction box collection station through the grasping mechanism. It can also automatically identify the position of the frame, remove the frame through mechanical support mechanical force, and transfer the removed frame to the frame collection station through the grasping mechanism.

[0040] In some embodiments, an obtuse-angle milling cutter is used to remove the glass on the second disassembly component from the second disassembly component, and the removed glass will be collected. In some embodiments, in order to speed up the removal of the glass, the second disassembly component needs to be preheated, and the preheating temperature is controlled at 90-150°C to soften the packaging film in the second disassembly component, thereby reducing the bonding strength of the packaging film to the glass, and removing the glass from the second disassembly component more quickly. In some embodiments, in addition to preheating the second disassembly component, the glass on the preheated second disassembly component is broken, for example, by rolling. Due to the presence of the packaging film and the welding strip (including the bus bar) in the organic wrapping layer, the second disassembly component at this time still appears in a sheet shape, and there are gaps between the glass fragments formed after the glass is broken, which facilitates the obtuse-angle milling cutter to penetrate into the gaps, and the glass can be removed from the second disassembly component more quickly.

[0041] Anaerobic low-temperature pyrolysis refers to continuous and dynamic low-temperature pyrolysis in an oxygen-free environment. In some embodiments, before anaerobic low-temperature pyrolysis of the organic coating layer, the organic coating layer is first broken to obtain organic coating layer fragments to ensure that the organic coating layer fragments are subjected to anaerobic low-temperature pyrolysis in a dynamic device that rotates at a uniform speed, and the pyrolysis process is heated evenly and quickly. Methods for breaking the organic coating layer include extrusion shearing and roller grinding. Preferably, the size of the organic coating layer fragments is less than 5cm×5cm, so that the organic coating layer fragments can be pyrolyzed more quickly and evenly, and the components in the organic coating layer fragments can be more fully separated from each other, which is conducive to improving the recovery rate of each component.

[0042] In some embodiments, the organic coating layer or organic coating layer fragments are placed in a closed oxygen-free low-temperature pyrolysis furnace, the temperature range of the oxygen-free low-temperature pyrolysis is between 300 and 450°C, and the gaseous components and solid components are obtained after the oxygen-free low-temperature pyrolysis. During the process of oxygen-free low-temperature pyrolysis of organic coating layer fragments, the organic macromolecular chain segments are broken to form pyrolysis gas and carbon black, so that the metals, silicon cells in the organic coating layer or organic coating layer fragments and the residual glass on the surface of the organic coating layer are separated. Further, the gaseous component is cooled, and the cooling method includes condensation or heat exchange cooling, and the components with higher boiling points in the gaseous components are cooled into liquid components, which are bio-oil. The components with lower boiling points in the gaseous components are collected or burned separately to provide heat for the oxygen-free low-temperature pyrolysis furnace. At the same time, the solid components are cooled, and the cooling method is heat exchange cooling, so that the temperature of the solid components after cooling is ≤75°C. The solid components include carbon black, metals, silicon cells and residual glass, and further screening is required to separate each component one by one. Among them, the residual glass is the glass slag that adheres to the surface of the organic coating layer or is partially embedded in the organic coating layer during the process of removing the glass with an obtuse milling cutter. Such glass slag is not completely removed by the obtuse milling cutter, resulting in a small amount of residual glass attached to the organic coating layer when it enters the oxygen-free low-temperature pyrolysis furnace. Preferably, the solid component is sieved with a linear sieve to obtain carbon black and a second solid component including silicon cells, metals and residual glass. Preferably, the second solid component is sieved with a specific gravity sieve to obtain silicon cells. Preferably, the second solid component is separated by eddy current or electrostatic separation to obtain metals and residual glass.

[0043] In some embodiments, the removal of the junction box, frame and glass is carried out in the photovoltaic power station, that is, the photovoltaic modules are removed from the photovoltaic power station system and immediately disassembled on site. This avoids the transportation procedure and improves the recycling speed. The organic coating layer obtained after the mechanical disassembly of the photovoltaic modules is transported and concentrated to one place for centralized oxygen-free low-temperature pyrolysis. The volume and weight of the organic coating layer will be much smaller than that of the photovoltaic modules just removed from the photovoltaic power station system, and the organic coating layer transported at one time will increase a lot, thereby improving the recycling speed. The organic coating layer is concentrated and continuously pyrolyzed, which is convenient for centralized classification and recovery of the products after pyrolysis, which is more environmentally friendly.

[0044] Parts not involved in the present invention are the same as the prior art or can be implemented by the prior art. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for recycling a photovoltaic module, wherein the photovoltaic module comprises an organic wrapping layer, glass, a frame and a junction box, characterized in that: The recovery method comprises the following steps: Identifying the frame size and positioning the frame; positioning the junction box; Dismantling the junction box to form a first disassembled component including the frame, the glass and the organic wrapping layer; Removing the frame to form a second disassembled component including the glass and the organic wrapping layer; Using a blunt-angle milling cutter to remove the glass to obtain the organic wrapping layer; The organic coating layer is pyrolyzed at low temperature without oxygen to obtain a gaseous component and a solid component; Condensation or heat exchange cooling of gaseous components to obtain liquid components; Cooling the solid component by heat exchange; The gaseous component, liquid component and solid component are collected separately according to their properties.

2. The method for recycling photovoltaic modules according to claim 1, characterized in that: Before disassembling the glass with the blunt-angle milling cutter, the second disassembling component is preheated.

3. The method for recycling photovoltaic modules according to claim 2, characterized in that: After preheating the second disassembling component, the glass is broken.

4. The method for recycling photovoltaic modules according to any one of claims 1 to 3, characterized in that: Before the organic coating layer is pyrolyzed at low temperature without oxygen, the organic coating layer is crushed to obtain organic coating layer fragments.

5. The method for recycling photovoltaic modules according to claim 4, characterized in that: The size of the organic coating fragments is less than 5 cm×5 cm.

6. The method for recycling photovoltaic modules according to claim 4, characterized in that: When the organic coating layer is pyrolyzed at low temperature without oxygen, the temperature range of the pyrolysis is between 300 and 450°C.

7. The method for recycling photovoltaic modules according to claim 1, characterized in that: The liquid component is bio-oil.

8. The method for recycling photovoltaic modules according to claim 1, characterized in that: The solid components include carbon black, silicon cells, metals and residual glass.

9. The method for recycling photovoltaic modules according to claim 8, characterized in that: The solid component is sieved by a linear sieve to obtain the carbon black and a second solid component including silicon cells, metals and residual glass.

10. The method for recycling photovoltaic modules according to claim 9, characterized in that: The second solid component is sieved with a specific gravity sieve to obtain the silicon cell.

11. The method for recycling photovoltaic modules according to claim 9, characterized in that: The second solid component is separated by eddy current or electrostatic separation to obtain the metal and the residual glass.