An extrusion peel photovoltaic panel backsheet removal device and method

Abstract

The application discloses a kind of extrusion stripping photovoltaic panel backboard removal device and method.The device includes conveying system, heating system, power system, extrusion device and high suction recovery system.Photovoltaic panel is conveyed to heating system by conveying system, overall heating to reduce the viscosity of EVA adhesive film between backboard and silicon layer.Power system drives extrusion device with curved surface profile and orthogonal grid microtexture surface, first compaction in vertical direction downward, then horizontally synchronous extrusion, so that backboard is completely clamped and lifted upward in face contact occlusion state, and is separated from EVA adhesive film layer.Finally, high suction recovery system is sucked by horn-shaped suction port in predetermined timing coordinated with stripping action.The application can realize stable and continuous stripping of flexible backboard, the stripping completeness of backboard is high, and the breakage rate of glass and battery piece is low, the degree of automation is significantly improved, thereby effectively improving the recovery efficiency and quality of each component in retired photovoltaic module.

Description

Technical Field

[0001] This invention belongs to the field of waste photovoltaic module recycling technology, specifically relating to a device and method for removing photovoltaic panel backsheets by extrusion peeling, which is particularly suitable for the efficient, continuous and automated dismantling and processing of retired crystalline silicon photovoltaic modules containing flexible polymer composite backsheets. Background Technology

[0002] As the global energy structure accelerates its transformation towards low-carbon and renewable energy, photovoltaic (PV) power generation, as a key component of clean energy, has experienced rapid development over the past two decades. According to publicly available statistics, since the end of the 20th century, the cumulative installed capacity of global PV modules has continued to climb, resulting in a massive stock of PV modules. Early-operated crystalline silicon PV modules have gradually reached their 15-25 year service life and are entering the retirement and disposal phase. Retired PV modules contain various recyclable components, including glass, aluminum frames, silicon cells, copper conductors, silver electrodes, solder ribbons, and polymer encapsulation materials. Glass and aluminum frames, due to their large volume, possess significant value, while key materials such as silicon, silver, and copper have high resource recycling value. Failure to effectively separate and selectively recycle these components will not only result in the loss of substantial valuable resources but may also pose potential environmental risks due to improper disposal of polymer materials. Therefore, efficient dismantling, deep sorting, and targeted material recycling of retired PV modules have become crucial aspects of PV lifecycle management and achieving the "dual carbon" goal.

[0003] Currently, commercially available crystalline silicon photovoltaic modules typically employ a laminated structure, consisting of a front cover glass, an upper ethylene-vinyl acetate (EVA) film, a string of solar cells, a lower EVA film, and a flexible polymer composite backsheet. The frame material is anodized aluminum. The flexible backsheet is often composed of multiple layers of thin films, including polyvinylidene fluoride (PVF), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), and polyamide (PA), with a thickness typically ranging from 0.25 mm to 0.45 mm. It possesses excellent insulation, moisture resistance, UV resistance, heat aging resistance, and mechanical protection. After lamination, the flexible backsheet is tightly bonded to the EVA film, solar cells, and front cover glass, forming a stable composite structure. During long-term outdoor operation, the back panel undergoes cross-linking and diffusion at the interface with the EVA film under the combined effects of multiple factors such as light, temperature and humidity cycles, ultraviolet radiation, and thermal aging. This results in uneven distribution of adhesion and a significant increase in peeling resistance, making it difficult to complete the peeling operation during the disassembly stage by simple tearing or scraping.

[0004] Given the flexible backsheet's bendability, stretchability, and tear resistance, it is prone to wrinkling, curling, misalignment, and tearing during disassembly. Forcibly pulling it off with external force typically leads to the following technical problems: First, uneven distribution of the peeling force in the width direction causes localized tearing and significant residue, which mixes with glass powder in subsequent glass sorting, contaminating the glass products. Second, excessive peeling force is transmitted to the underlying EVA film and battery strings, causing cell breakage and glass edge cracks, significantly reducing the recycling quality of glass and silicon. Third, the flexible backsheet tends to bend and accumulate at the front of the equipment during peeling, causing jamming and equipment downtime, severely impacting continuous production. Therefore, the peeling of the flexible backsheet is essentially a complex process involving the coordinated control of multiple variables such as temperature, stress state, peeling path, and continuous conveying. Existing methods using simple heating combined with manual labor or a single mechanical device are insufficient to simultaneously achieve the three key indicators of peeling integrity, glass integrity, and production efficiency.

[0005] Currently, the main methods for handling retired photovoltaic module backsheets include the following: (I) Manual removal: Workers heat the module using a heating plate or hot air gun, and then peel off the backsheets one by one by hand or with simple tools. This method is highly adaptable to the aging state of the backsheets, but it has problems such as high labor intensity, low efficiency, and poor working environment hygiene. In addition, operators are exposed to high temperatures and fumes generated by polymer decomposition for a long time, making it difficult to achieve large-scale processing; (II) Mechanical scraping: The backsheets are directly cut using blades, scrapers, or milling cutters. This method is prone to scratches on the glass surface, which may damage the underlying cell strings. The backsheet residue is mostly in the form of debris, increasing the difficulty of sorting, and generating a large amount of dust; (III) Hot knife separation: The glass and backsheet interfaces are thermally melted and cut using heated blades. This method requires extremely high coordination and control of hot knife temperature, travel speed and downward pressure, and has a narrow process window. When encountering severely aged areas of the backsheet, it is prone to cutting deviation or even damage to the glass; (iv) Overall heating and peeling method: After heating the entire component to the EVA softening temperature, it is peeled off with the help of rollers or grippers. This method is the most mature solution among the above technologies, but existing equipment generally has shortcomings such as difficulty in achieving closed-loop control of peeling force, poor lateral synchronization, insufficient resistance to backsheet rebound, and failure to achieve fine coupling between peeling and recycling sequence. This results in large fluctuations in the integrity rate of backsheet peeling, often requiring manual secondary cleaning, and the level of automation is limited.

[0006] Retired photovoltaic modules come from diverse sources, encompassing different manufacturers, production years, and backsheet material systems, resulting in significant performance variations. Specifically, backsheet thickness ranges from 0.25mm to 0.45mm, backsheet aging varies widely, from slight yellowing to severe powdering, and the adhesion between the backsheet and the EVA layer changes by more than 30%. Existing equipment suffers from limited adjustable force ranges, fixed peeling parameters, and a lack of adaptive adjustment capabilities for batch-to-batch module differences, often requiring equipment readjustment for different batches. This limits both production line efficiency and recycling quality. Therefore, there is an urgent need for a removal device and method capable of stable and continuous peeling of flexible backsheets with good process adaptability. Summary of the Invention

[0007] This invention aims to address the problems of unstable peeling processes, easy backsheet residue, easy damage to glass and solar cells, insufficient lateral synchronization, inadequate coupling of peeling and recycling timing, and poor adaptability to different module specifications in existing technologies. It provides a photovoltaic module backsheet removal device and method based on extrusion peeling. This method reduces the viscosity of the EVA film by heating the entire module. Using an extrusion device with curved contours and orthogonal mesh micro-textured surfaces, planar contact and interlocking are first achieved in the vertical direction. Then, extrusion forces are applied synchronously and in opposite directions in the horizontal direction, causing the backsheet to be lifted and peeled off along the peeling surface while clamped. A high-suction recycling system synchronized with the peeling action promptly retrieves the peeled backsheet. This device and method effectively achieve stable and continuous peeling of flexible backsheets, significantly reducing backsheet breakage and residue rates, while also minimizing damage to glass and solar cells, and improving the efficiency and quality of subsequent material recycling.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution.

[0009] In a first aspect, the present invention discloses an extrusion-peel photovoltaic panel backsheet removal device, comprising a conveying system, a heating system, a power system, extrusion devices, and a high-suction recovery system; the power system, extrusion devices, and high-suction recovery system are all located above the heating system, and the movement of the extrusion devices is driven by the power system; wherein, the conveying system is used to convey the photovoltaic panel to the heating system, and the heating system is used to heat the entire photovoltaic panel to reduce the viscosity of the EVA film between the backsheet and the silicon layer; the extrusion devices are at least two sets, symmetrically arranged, and each extrusion device consists of a device body and a high-temperature resistant elastic layer covering its outer surface, the contour of the device body in contact with the backsheet is an outwardly convex curved surface, and the surface of the high-temperature resistant elastic layer is provided with a micro-textured structure; the power system includes a vertical drive unit for driving the extrusion devices to move vertically and a transverse drive unit for driving the two sets of extrusion devices to move synchronously towards each other horizontally; the suction port of the high-suction recovery system faces the peeling surface and is used to suck up the peeled backsheet during the process of the extrusion devices clamping the backsheet and moving upward.

[0010] In this invention, the heating system includes a resistance heating table. The table surface is made of aluminum alloy and has a built-in temperature control function to maintain the table surface temperature within the range of 120°C to 160°C. This temperature range can meet the softening requirements of common EVA films and effectively prevent excessive release of polymer pyrolysis fumes caused by overheating. The table surface thickness is set to 15mm to 25mm, and the flatness of the table surface is not less than 0.05mm / m to ensure uniform temperature distribution throughout the heating process of the entire board.

[0011] In this invention, the conveying system consists of two flat belt conveyors connected in sequence, respectively located at the inlet and outlet ends of the heating system. Limiting baffles are provided on both sides of the connection between the conveying system and the heating table. These baffles extend along the conveying direction of the photovoltaic panel, and their spacing matches the width of the photovoltaic panel, ensuring smooth axial movement of the photovoltaic panel during conveying and preventing lateral deviation. This structural design helps the photovoltaic panel remain centered when entering the heating position, ensuring balanced force when the two subsequent extrusion devices apply pressure towards each other.

[0012] In this invention, the vertical drive unit of the power system consists of a vertical motor and its driven screw transmission mechanism; the horizontal drive unit includes a horizontal motor and a crossbar driven by a belt. The front and rear sections of the crossbar adopt a positive and negative tooth structure to ensure that the two sets of extrusion devices connected to both ends of the crossbar can move synchronously and symmetrically towards each other; the pitch range of the positive and negative tooth structure is 3mm to 8mm, and the transition area of ​​the opposite tooth direction section is marked with a zero position mark; the horizontal motor is a servo motor with a pulse frequency of not less than 2500Hz, thereby ensuring that the synchronous position deviation of the two sets of extrusion devices does not exceed 0.2mm; this invention uses a single power source to drive the positive and negative tooth structure, which can structurally avoid the peeling offset problem caused by the asynchronous extrusion devices on both sides.

[0013] In this invention, the body of the extrusion device is made of metal, and the radius of curvature of its convex surface profile is preferably set within the range of 80mm to 150mm. The high-temperature resistant elastic layer is made of high-temperature resistant silicone rubber, with a thickness preferably controlled between 3mm and 5mm, a Shore hardness of 60HA to 75HA, and the ability to continuously withstand temperatures not lower than 200℃. The surface of this elastic layer has a micro-textured embossed structure, with the texture distributed in an orthogonal grid pattern, a grid spacing of 0.5mm to 1.5mm, a texture depth maintained within the range of 0.1mm to 0.3mm, and a texture cross-sectional shape of V-shape or trapezoidal. This micro-textured structure can form a large number of micro-interlocking points with the back plate under pressure, effectively increasing the instantaneous friction coefficient, preventing the extrusion device from slipping relative to the back plate, ensuring stable clamping of the back plate, and converging and contracting towards the center with the horizontal inward pushing action of the extrusion device to form a reliable clamping state.

[0014] In this invention, the extrusion device is embedded with a pressure sensor, which is located between the device body and the high-temperature resistant elastic layer. The sensor has a range of 0 to 1000 N and a resolution of not less than 1 N. It can monitor the vertical pressure applied to the back plate by the extrusion device in real time and work in conjunction with the control system to achieve closed-loop pressure control. When the detected pressure reaches a preset threshold (preferably set between 300 N and 500 N, particularly preferably 400 N), the vertical drive unit will immediately stop its downward movement to prevent the lower glass from cracking due to excessive force and to avoid damage to the heating platform.

[0015] In this invention, the suction port of the high-suction recovery system is designed in a trumpet shape, with its opening diameter matching the width of the photovoltaic panel backsheet, and the suction port axis perpendicular to the peeling surface of the photovoltaic panel. The suction port is connected to a negative pressure extraction pipe via a flange, and symmetrical stabilizing frames are provided on both sides of the pipe. The negative pressure value of the high-suction recovery system is set within the range of -15kPa to -30kPa. This structure can form a uniformly distributed negative pressure field in the width direction of the backsheet, effectively reducing the secondary tensile stress generated on the backsheet during the extraction process.

[0016] This invention also includes a control system electrically connected to the heating system, power system, pressure sensor, and high-suction recovery system. The control system is configured to delay the activation of the negative pressure source of the high-suction recovery system within 120 to 180 milliseconds after the extrusion device begins to move the backplate upwards. This timing-coupled control ensures that negative pressure is applied only after the backplate has completely detached from the EVA film layer, preventing premature application of negative pressure before peeling is complete, which could cause the backplate to spring back and tear. It also prevents the delayed activation of negative pressure from causing the backplate to fall or shift position.

[0017] Secondly, the present invention provides a method for removing the backsheet of a photovoltaic panel using a compression peeling method. This method is implemented using the aforementioned apparatus and specifically includes the following steps: S1. Conveying Steps: The photovoltaic panels to be recycled are conveyed to the heating positioning area of ​​the heating system through the conveying system; S2. Heating Step: Start the heating system and heat the entire photovoltaic panel for a predetermined time to reduce the viscosity of the EVA film between the backsheet and the silicon layer to a preset value. S3, Vertical extrusion step: The vertical drive unit in the power system drives the extrusion device to move downward, so that the micro-textured surface of the extrusion device contacts the back plate surface and produces controllable deformation. When the force detected by the pressure sensor reaches the preset vertical force threshold, the vertical drive unit stops moving. S4, Horizontal opposing extrusion step: The transverse drive unit of the power system drives two sets of extrusion devices to extrude synchronously in the horizontal direction, so that the back plate is gathered and contracted towards the center in the horizontal direction under the clamping action of the two sets of extrusion devices, forming a stable clamping state. S5, Lifting and Peeling Step: The vertical drive unit drives the two sets of extrusion devices holding the back plate to move upward synchronously, so that the back plate is completely separated from the EVA film layer. S6. Recycling Step: After a preset timing coupling time is delayed after step S5, the negative pressure source of the high suction recycling system is activated, and the stripped backplate is sucked into the recycling pipe through the suction port.

[0018] In this invention, in step S2, the heating temperature of the heating system is set in the range of 120°C to 160°C, and the heating duration is 10 to 15 seconds; in step S3, the preset vertical force threshold is 300N to 500N.

[0019] In this invention, in step S4, the two sets of extrusion devices move horizontally towards each other at a speed ranging from 20 mm / s to 60 mm / s, and the stroke of the opposite movement is 1 / 3 to 1 / 2 of the width of the photovoltaic panel; in step S6, the timing coupling time is set to 120 ms to 180 ms, and the negative pressure value when the high suction recovery system is started is maintained between -15 kPa and -30 kPa.

[0020] Compared with the prior art, the present invention exhibits the following significant advantages: (1) The extrusion device structure with an outwardly convex curved surface profile enables the extrusion stress to be uniformly distributed along the curvature direction of the back plate, effectively preventing glass edge cracks and cell breakage caused by local stress concentration, and significantly improving the glass integrity rate. Test results show that, compared with the planar extrusion head, the curved extrusion head of the present invention reduces the glass breakage rate from about 5.6% to about 0.8%.

[0021] (2) The orthogonal mesh-like micro-texture structure set on the surface of the high-temperature resistant silicone rubber layer generates dense micro-interlocking points with the back plate during the compression process. Its instantaneous friction coefficient is about 2.5 times higher than that of a smooth surface, thereby ensuring that the back plate can achieve stable clamping during the horizontal extrusion stage, avoiding slippage, and providing solid mechanical boundary support for the subsequent lifting and peeling process.

[0022] (3) By adopting a crossbar forward and reverse tooth synchronous drive mechanism, the two sets of extrusion devices are driven by the same servo power source and move synchronously, and the synchronous position deviation is controlled within the range of no more than 0.2mm; during the peeling process, the back plate is subjected to symmetrical force, which effectively avoids the peeling offset phenomenon caused by the difference in servo parameters of the dual drive system.

[0023] (4) Through a dual closed-loop control strategy combining pressure and temperature closed loops, the device can adapt to photovoltaic panels from different manufacturers, with different service years and backsheet thicknesses. It still maintains a high peeling integrity rate on samples with backsheet thicknesses ranging from 0.25mm to 0.45mm and with significant differences in aging.

[0024] (5) In the high-suction recovery system, a precise timing coupling of 120ms to 180ms is achieved between the horn-shaped suction port and the peeling action. The negative pressure is initiated after the extrusion device begins its upward movement, ensuring that the negative pressure is applied only after the backplate detaches from the EVA film, thus ensuring that the peeled backplate can be completely and directionally sucked into the recovery pipeline. The integrity rate of backplate peeling is improved from approximately 82% in the prior art to over 96%, providing a high-quality raw material guarantee for the subsequent resource recovery of polymer components.

[0025] (6) This device fully covers the entire automated process of conveying, heating, extrusion, peeling and recycling. The processing cycle of a single unit is 40 to 60 seconds per piece (based on a standard 60-piece assembly of 1650mm×992mm). Compared with manual tearing methods, the efficiency is increased by more than five times; compared with mechanical scraping methods, the residue rate is reduced by about 70%, demonstrating significant industrial application potential and economic benefits. Attached Figure Description

[0026] To clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings involved in the description of the embodiments are briefly described below. Obviously, the drawings described below are only illustrative of some embodiments of the present invention. For those skilled in the art, other related drawings can be derived based on the above drawings without creative modifications.

[0027] Figure 1 This is a schematic diagram of the overall structural layout of the extrusion-peeling photovoltaic panel backsheet removal device shown in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the power system structure used in the extrusion-peeling photovoltaic panel backsheet removal device in this embodiment of the invention.

[0029] Figure 3 This is a partially enlarged schematic diagram of the curved extrusion device in the extrusion peeling photovoltaic panel backsheet removal device in an embodiment of the present invention.

[0030] Figure 4 This is a top view and an enlarged schematic diagram after being cut along the AA direction, showing the orthogonal grid-like microtextured embossed structure on the surface of the high-temperature resistant rubber layer 401 in this embodiment of the invention.

[0031] Figure 5 This is the structure of a high-suction recycling system for a pressure-stripping photovoltaic panel backsheet removal device in an embodiment of the present invention.

[0032] Figure 6 This is the operation sequence flow of the extrusion peeling method described in this invention.

[0033] Figure 7This is a comparison of the key process parameters in Embodiments 1, 2, and 3 of the present invention.

[0034] Figure 8 The results of comparative tests on four photovoltaic panel backsheet peeling methods are presented, focusing on four indicators: peeling integrity rate, glass breakage rate, cell breakage rate, and processing cycle time.

[0035] The specific meanings of the labels in the attached diagrams are as follows: 1-Conveying system; 2-Heating system; 3-Power system; 301-Positive and negative toothed crossbar; 302-Horizontal motor; 303-Vertical motor; 304-Belt; 4-Extrusion device; 401-High temperature resistant rubber layer; 402-Pressure sensor assembly; 5-High suction recovery system; 501-Suction port. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will now be described in detail and completely with reference to the accompanying drawings. It should be noted that the embodiments are only some examples of the present invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments disclosed in the present invention without creative effort are also within the scope of protection of the present invention. The directional terms used in the following description, such as "upper," "lower," "horizontal," "vertical," "front," and "rear," are based on the states shown in the accompanying drawings and should not be considered as limitations on the present invention.

[0037] Example 1

[0038] This embodiment relates to a compression-peeling photovoltaic panel backsheet removal device. See [link to relevant documentation]. Figures 1 to 4 The device consists of a conveying system 1, a heating system 2, a power system 3, an extrusion device 4, a high-suction recovery system 5, and a control system.

[0039] The conveying system 1 consists of two flat belt conveyors connected in sequence, respectively arranged at the inlet and outlet ends of the heating system 2, with the belt width exceeding the maximum width of the photovoltaic panel to be processed. Limiting baffles are installed on both sides of the connection between the two flat belt conveyors and the heating system 2. These limiting baffles extend along the conveying direction of the photovoltaic panel, and the spacing between the limiting baffles is 2mm to 5mm wider than the width of the photovoltaic panel, ensuring stable axial movement of the photovoltaic panel during conveying and preventing lateral displacement.

[0040] Heating system 2 includes a resistance heating table, the working surface of which is made of a 20mm thick aluminum alloy plate. The flatness of the table surface is controlled to be no more than 0.05mm / m to ensure uniform temperature distribution across the heating plate. The heating table has a built-in temperature control function, which uses a closed-loop control system to regulate the table surface temperature with a temperature control accuracy of ±2℃. In this embodiment, the heating temperature is set to 140℃, and the heating duration is 12 seconds.

[0041] The power system 3 is mounted on a support frame above the heating system 2 and includes a vertical motor 303, a horizontal motor 302, a belt 304, and a forward and reverse gear crossbar 301. The vertical motor 303 drives two sets of extrusion devices 4 to move synchronously vertically via a screw drive mechanism; the horizontal motor 302 drives the forward and reverse gear crossbar 301 to rotate around its axis via the belt 304. The front and rear sections of the forward and reverse gear crossbar 301 are provided with threads in opposite directions with a pitch of 5mm, so that the two sets of extrusion devices 4 sleeved at both ends of the crossbar 301 can achieve synchronous, symmetrical, and opposite movements when the crossbar rotates. Both the horizontal motor 302 and the vertical motor 303 are servo motors with a pulse frequency of not less than 2500Hz. Combined with ball screws and linear guides, the synchronous position deviation of the two sets of extrusion devices 4 is guaranteed to be no more than 0.2mm.

[0042] The extrusion devices 4 are positioned below the vertical motor 303, arranged symmetrically in two groups. Each group of extrusion devices 4 consists of a device body, a high-temperature resistant rubber layer 401, and a pressure sensor 402. The device body is made of 304 stainless steel, and its contact portion with the back plate has an outwardly convex curved surface with a radius of curvature of 100mm. The high-temperature resistant rubber layer 401 is made of high-temperature resistant silicone rubber with a Shore hardness of 65HA, capable of continuously withstanding temperatures not lower than 230℃. It covers the outer side of the curved contour of the device body and has a thickness of 4mm. The outer surface of the high-temperature resistant rubber layer 401 has a micro-textured embossed structure with orthogonal grid patterns arranged in a grid pattern. The grid spacing is 1.0mm, the texture depth is 0.2mm, and the cross-sectional shape is V-shaped to enhance the instantaneous interlocking friction between it and the back plate surface. The pressure sensor 402 is embedded between the device body and the high-temperature resistant rubber layer 401. It has a range of 1000N and a resolution of 1N. In this embodiment, the Zhongnuo Sensor BSCC-H2 model is selected. This sensor is electrically connected to the control system.

[0043] The high-suction recovery system 5 is positioned directly above the heating system 2 and includes a suction port 501, a negative pressure extraction pipe, a stabilizing frame, and a flange. The suction port 501 is trumpet-shaped with a smooth, gradually narrowing inner wall and an opening diameter of 1100 mm, matching the width of the photovoltaic panel backsheet. Its axis is perpendicular to the peeling surface of the photovoltaic panel. Symmetrically arranged stabilizing frames are located on both sides of the negative pressure extraction pipe, connected to the pipe via flanges to prevent tilting or collapse. The negative pressure extraction pipe is connected to an external vacuum pump unit; in this embodiment, the negative pressure setting is -22 kPa.

[0044] The control system consists of a programmable logic controller (PLC) and a human-machine interface (HMI), which are electrically connected to the heating system 2, the power system 3, the pressure sensor 402, the vacuum pump in the high-suction recovery system 5, and the drive motor of the conveying system 1. The control system has an embedded time-coupled control program, which is set to start the negative pressure source of the vacuum pump 150ms after the lifting action of the back plate clamped by the extrusion device 4 begins, and to switch the vacuum pump to standby mode after the back plate is sucked into the negative pressure extraction pipe.

[0045] Based on the above-mentioned device, this embodiment further proposes a method for removing the backsheet of a photovoltaic panel by extrusion peeling, the specific steps of which are as follows: Step S1: The conveying system 1 transports 60 crystalline silicon photovoltaic panels with a standard size of 1650mm×992mm to be recycled to the heating area of ​​the heating system 2, with the glass side of the photovoltaic panels facing down and in close contact with the surface of the heating table, and the back panel facing up.

[0046] Step S2: Start heating system 2 and maintain the temperature of the heating table surface at 140°C. Heat the entire photovoltaic panel for 12 seconds to reduce the viscosity of the EVA film between the backsheet and the silicon layer to a state suitable for peeling.

[0047] In step S3, the vertical motor 303 drives the two sets of extrusion devices 4 to move from top to bottom. When the pressure sensor 402 detects that the vertical pressure applied by the high-temperature resistant rubber layer 401 to the back plate reaches 400N, the control system stops the vertical motor 303. At this time, the micro-textured surface of the extrusion device 4 and the surface of the back plate have formed a stable surface contact engagement.

[0048] Step S4: Start the horizontal motor 302, drive the positive and negative toothed crossbar 301 to rotate through the belt 304, so that the two sets of extrusion devices 4 move synchronously in opposite directions by 300mm at a speed of 40mm / s, so that the back plate is clamped in the horizontal direction and slightly converges and shrinks towards the center.

[0049] In step S5, after the horizontal motor 302 stops, the vertical motor 303 drives the two sets of extrusion devices 4 to move 60mm in the vertical direction in the opposite direction, so as to achieve complete separation of the back plate and the EVA film layer.

[0050] Step S6: 150 milliseconds after the start of step S5, the control system activates the vacuum pump of the high-suction recovery system 5. The suction port 501 generates a negative pressure of -22 kPa, uniformly drawing the peeled backsheet into the negative pressure pipe, completing the removal process for a single photovoltaic panel backsheet. At this point, a small amount of EVA film remains between the silicon solar cell and the glass, and therefore will not be sucked away by the high-suction recovery system 5. It continues to remain on the heating platform, where subsequent processes will further separate the EVA film from the glass and the solar cell.

[0051] Example 2

[0052] This embodiment proposes a novel device and method for removing the backsheet of a photovoltaic panel using an extrusion peeling process. It differs from Embodiment 1 in that the photovoltaic panel being processed is a 72-cell half-cell module with dimensions of 1980mm × 1140mm, a backsheet thickness of 0.32mm, a service life of approximately 18 years, and significant yellowing of the backsheet. For this module size, the spacing between the limiting baffles is set to 1145mm; the heating temperature is adjusted to 150℃, and the heating duration is extended to 15 seconds; the radius of curvature of the extrusion device 4 is adjusted to 130mm, and the Shore hardness of the high-temperature resistant rubber layer 401 is set to 70HA; the preset vertical force threshold in step S3 is 450N; in step S4, the horizontal opposing movement speed of the two sets of extrusion devices 4 is adjusted to 30mm / s, and the opposing movement stroke is set to 360mm; in step S6, the timing coupling time is adjusted to 170ms, and the negative pressure value is set to -26kPa. The remaining structural configuration and operating procedures are consistent with Embodiment 1. Experimental results show that this embodiment can still achieve a high peel integrity rate for aged backsheets, verifying the excellent adaptability of the process of the present invention.

[0053] Example 3

[0054] This embodiment proposes a simplified extrusion-peel photovoltaic panel backsheet removal device. Its main difference from Embodiment 1 lies in the following: the lateral drive unit in the power system 3 uses two symmetrically arranged servo motors, each independently driving one of the two extrusion devices 4. Through a synchronization control algorithm embedded in the control system, the synchronous and coordinated movement of the two extrusion devices 4 in the horizontal direction is achieved. The high-temperature resistant rubber layer 401 of the extrusion device 4 uses ethylene propylene diene monomer (EPDM) rubber instead of silicone rubber. This material has a continuous temperature resistance of not less than 180°C and is less expensive than silicone rubber. This embodiment is suitable for applications with relatively mild backsheet aging, less stringent requirements for peeling synchronization, and cost-sensitive equipment.

[0055] Figure 7 This is a comparison of the key process parameters in Embodiments 1, 2, and 3 of the present invention.

[0056] To verify the beneficial effects of this invention, the inventors conducted backsheet removal tests on the same batch of retired crystalline silicon photovoltaic modules (n=30 modules, standard 60-cell modules with dimensions of 1650mm×992mm, and a service life of approximately 15 years) using the following four methods: Method A was manual tearing; Method B was mechanical scraping; Method C was overall heating and peeling with a planar extrusion head; and Method D was the extrusion peeling removal method proposed in this invention (using the device and process parameters in Example 1). The main evaluation indicators covered backsheet peeling integrity rate, glass breakage rate, cell breakage rate, and single-panel processing cycle time.

[0057] like Figure 8 As shown in the experimental results, Method D of the present invention significantly outperforms the other three comparative methods in four key indicators: the backsheet peeling integrity rate is improved by approximately 14 percentage points compared to the existing best solution C, reaching approximately 96%; the glass breakage rate is significantly reduced from approximately 5.6% in Method C to approximately 0.8%, a reduction of over 85%; the cell breakage rate is reduced from approximately 6.8% to approximately 1.2%, a reduction of over 82%; and the single-panel processing cycle time is shortened from 75 seconds to 50 seconds, with an efficiency improvement of approximately 33%. These data fully demonstrate that the present invention, through the synergistic design of the curved extrusion head and the orthogonal mesh micro-textured surface, closed-loop pressure control, and precise coupling of peeling and recycling timing, achieves significant improvements in four core performance aspects: peeling integrity rate, glass integrity rate, cell integrity rate, and processing efficiency, meeting the industrial requirements for automation level and process stability in the large-scale recycling of decommissioned photovoltaic modules.

[0058] Although the above embodiments have disclosed the present invention in detail, the scope of application of the present invention is not limited to the contents described in the specification and specific embodiments, and it is equally applicable to various fields to which the present invention applies. Those skilled in the art can make corresponding modifications based on the principles of the present invention. Without departing from the general technical concept covered by the claims and their equivalents, the present invention is not limited to the embodiments illustrated in the specific details and drawings. Any changes, equivalent substitutions, and improvements made within the scope of the basic spirit and technical principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photovoltaic panel backsheet removal device using an extrusion peeling method, characterized in that, It includes a conveying system, a heating system, a power system, extrusion devices, and a high-suction recovery system. The power system, extrusion devices, and high-suction recovery system are all located above the heating system, and the movement of the extrusion devices is driven by the power system. The conveying system is used to transport the photovoltaic panel to the heating system, which heats the entire photovoltaic panel to reduce the viscosity of the EVA film between the backsheet and the silicon layer. There are at least two sets of extrusion devices arranged symmetrically. Each extrusion device consists of a device body and a high-temperature resistant elastic layer covering its outer surface. The contour of the device body in contact with the backsheet is a convex curved surface, and the surface of the high-temperature resistant elastic layer has a micro-textured structure. The power system includes a vertical drive unit for driving the extrusion devices to move vertically and a lateral drive unit for driving the two sets of extrusion devices to move synchronously towards each other horizontally. The suction port of the high-suction recovery system faces the peeling surface to suck up the peeled backsheet during the process of the extrusion devices clamping the backsheet and moving upward.

2. The extrusion-peel photovoltaic panel backsheet removal device according to claim 1, characterized in that, The heating system includes a resistance heating table. The table surface is made of aluminum alloy and has a built-in temperature control function to maintain the table surface temperature within the range of 120℃ to 160℃. The table surface thickness is set to 15mm to 25mm, and the flatness of the table surface is not less than 0.05mm / m to ensure uniform temperature distribution throughout the heating process of the entire board.

3. The extrusion-peel photovoltaic panel backsheet removal device according to claim 1, characterized in that, The conveying system consists of two flat belt conveyors connected in sequence, which are respectively arranged at the feed end and discharge end of the heating system. Limiting baffles are provided on both sides of the connection between the conveying system and the heating table. The limiting baffles extend along the conveying direction of the photovoltaic panel, and their spacing matches the width of the photovoltaic panel, which is intended to ensure that the photovoltaic panel moves stably along the axial direction and prevent lateral displacement.

4. The extrusion-peeling photovoltaic panel backsheet removal device according to claim 1, characterized in that, The vertical drive unit consists of a vertical motor and its driven lead screw transmission mechanism; the horizontal drive unit includes a horizontal motor and a crossbar driven by a belt. The front and rear sections of the crossbar adopt a positive and negative tooth structure to ensure that the two sets of extrusion devices connected to both ends of the crossbar can move synchronously and symmetrically towards each other; the pitch range of the positive and negative tooth structure is 3mm to 8mm, and the transition area of ​​the opposite tooth direction section is marked with a zero position mark; the horizontal motor is a servo motor with a pulse frequency of not less than 2500Hz, thereby ensuring that the synchronous position deviation of the two sets of extrusion devices does not exceed 0.2mm.

5. The extrusion-peeling photovoltaic panel backsheet removal device according to claim 1, characterized in that, The device body is made of metal, and the radius of curvature of the curved profile of the part in contact with the back plate ranges from 80mm to 150mm; the high-temperature resistant elastic layer is made of high-temperature resistant silicone rubber with a thickness between 3mm and 5mm, a Shore hardness of 60HA to 75HA, and can withstand a temperature of not less than 200℃ continuously; the surface of the high-temperature resistant silicone rubber layer has a micro-textured embossed structure, the texture is distributed in an orthogonal grid pattern, the grid spacing is between 0.5mm and 1.5mm, the texture depth is between 0.1mm and 0.3mm, and the texture cross-sectional shape is V-shaped or trapezoidal.

6. The extrusion-peel photovoltaic panel backsheet removal device according to claim 1, characterized in that, The extrusion device incorporates a pressure sensor embedded between the device body and the high-temperature resistant elastic layer. This sensor has a range of 0 to 1000 N and a resolution of at least 1 N, used to monitor the force applied to the backsheet by the extrusion device in real time. The high-suction recovery system has a funnel-shaped suction port with an opening diameter adapted to the width of the photovoltaic panel backsheet. The suction port axis is perpendicular to the peeling surface of the photovoltaic panel. This suction port connects to a negative pressure suction pipe, on both sides of which are symmetrically arranged stabilizing frames connected to the pipe via flanges. The negative pressure value of the high-suction recovery system is set within the range of -15 kPa to -30 kPa.

7. The extrusion-peel photovoltaic panel backsheet removal device according to any one of claims 1-6, characterized in that, It also includes a control system, which is electrically connected to the heating system, the power system, the pressure sensor and the high-suction recovery system; the control system is configured to activate the negative pressure source of the high-suction recovery system after a delay of 120 to 180 milliseconds after the upward movement of the clamping back plate of the extrusion device begins.

8. A method for removing the backsheet of a photovoltaic panel by extrusion peeling, implemented using the extrusion peeling photovoltaic panel backsheet removal device according to claim 1, characterized in that, Includes the following steps: S1. Conveying Steps: The photovoltaic panels to be recycled are conveyed to the heating positioning area of ​​the heating system through the conveying system; S2. Heating Step: Start the heating system to heat the entire photovoltaic panel for a predetermined time so that the viscosity of the EVA film between the backsheet and the silicon layer is reduced to a preset value. S3, Vertical extrusion step: The vertical drive unit in the power system drives the extrusion device to move downward, so that the micro-textured surface of the extrusion device contacts the back plate surface and produces controllable deformation. When the force detected by the pressure sensor reaches the preset vertical force threshold, the vertical drive unit stops moving. S4, Horizontal opposing extrusion step: The transverse drive unit of the power system drives two sets of extrusion devices to extrude synchronously in the horizontal direction, so that the back plate is gathered and contracted towards the center in the horizontal direction under the clamping action of the two sets of extrusion devices, forming a stable clamping state. S5, Lifting and Peeling Step: The vertical drive unit drives the two sets of extrusion devices holding the back plate to move upward synchronously, so that the back plate is completely separated from the EVA film layer. S6. Recycling Step: After a preset timing coupling time is delayed after step S5, the negative pressure source of the high suction recycling system is activated, and the stripped backplate is sucked into the recycling pipe through the suction port.

9. The method for removing the backsheet of a photovoltaic panel by extrusion peeling according to claim 8, characterized in that, In step S2, the heating temperature of the heating system is set in the range of 120°C to 160°C, and the heating duration is 10 to 15 seconds; in step S3, the preset vertical force threshold is 300N to 500N.

10. The method for removing the backsheet of a photovoltaic panel by extrusion peeling according to claim 8, characterized in that, In step S4, the two sets of extrusion devices move horizontally towards each other at a speed ranging from 20 mm / s to 60 mm / s, and the stroke of the opposite movement is 1 / 3 to 1 / 2 of the width of the photovoltaic panel; in step S6, the timing coupling time is set to 120 ms to 180 ms, and the negative pressure value when the high suction recovery system is started is maintained between -15 kPa and -30 kPa.

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