Laser processing method for recycling photovoltaic module

Abstract

The invention provides a laser processing method for recycling a photovoltaic module, which comprises the following steps of: processing the photovoltaic module by adopting first laser, and forming a light absorption layer on an adhesive film; and carrying out hot processing on the adhesive film by adopting second laser to reduce the viscosity of the adhesive film, so that the adhesive film is easily separated from the glass. According to the laser treatment method for recycling the photovoltaic module, different types of adhesive film packaging materials can be effectively treated, and the purpose of separating the adhesive film from the glass is achieved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and more specifically to a laser processing method for recycling photovoltaic modules. Background Technology

[0002] Current technologies for recycling photovoltaic (PV) modules generally employ high-temperature incineration, chemical solvent methods, or physical methods. High-temperature incineration removes the organic components of the encapsulation materials, separating the cells from the glass. Chemical solvent methods use inorganic or organic solvents to dissolve the organic encapsulation materials in the PV module, achieving separation of the cells from the glass. Physical methods separate the cells and glass through mechanical crushing. However, high-temperature incineration often involves complex exhaust gas treatment issues, chemical treatment causes wastewater pollution, and physical methods result in severe pulverization of materials such as glass and cells, along with high energy consumption and losses during the process. Therefore, there is an urgent need for a fast, simple, low-energy, and pollution-free method for recycling PV modules.

[0003] Currently, laser heat treatment has become a feasible method. The most mature laser treatment method is direct scanning of photovoltaic modules with infrared continuous laser. The encapsulation materials (films) used in existing photovoltaic modules mainly include EVA, EPE, and POE. However, the infrared continuous laser scanning method can only process photovoltaic modules with EVA film. This is because the film itself is transparent and has a low laser absorption rate. When the infrared continuous laser directly scans the photovoltaic module, only EVA film, due to its low melting point of 130℃, melts and remains in a fluid state after infrared continuous laser treatment, allowing for separation of the film from the glass at high temperatures. POE, EPE, and other film materials have high melting points and cannot be separated from the glass. Furthermore, because the film has a low laser absorption rate, laser treatment of photovoltaic modules inevitably leads to a waste of laser energy. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a laser processing method for recycling photovoltaic modules. A first laser is used to process the encapsulant film of the photovoltaic module to form a light-absorbing layer on the encapsulant film, and a second laser is used to perform thermal processing on the encapsulant film to reduce the adhesiveness of the encapsulant film and facilitate the separation of the encapsulant film from the glass.

[0005] To achieve the above objectives, the present invention provides a laser processing method for recycling photovoltaic modules, comprising: 1. using a first laser to process the photovoltaic module to form a light-absorbing layer on the adhesive film; and using a second laser to thermally process the adhesive film to reduce its stickiness.

[0006] As a further improvement of the present invention, the method of forming a light-absorbing layer on the adhesive film is to process the photovoltaic module with a first laser, and the method of forming a light-absorbing layer on the adhesive film is to process the adhesive film of the photovoltaic module with a first laser to change the color of the adhesive film.

[0007] As a further improvement of the present invention, the first laser is a picosecond laser or a femtosecond laser, or a nanosecond laser with a pulse width of less than 100 ns.

[0008] As a further improvement of the present invention, the wavelength of the first laser is 355–1064 nm, and / or,

[0009] The energy density of the first laser is 0.75–8.4 J / cm². 2 .

[0010] As a further improvement of the present invention, the focal point of the first laser is located on the surface of the adhesive film near the glass side, or inside the adhesive film on that side.

[0011] As a further improvement of the present invention, the first laser processing area is the entire area of ​​the photovoltaic module or a part of the entire area of ​​the photovoltaic module.

[0012] As a further improvement of the present invention, the scanning sequence of the first laser is from the edge of the film to the middle.

[0013] As a further improvement of the present invention, the second laser is a continuous infrared laser, or the second laser is a pulsed infrared laser with a pulse width greater than 150 ns.

[0014] As a further improvement of the present invention, the energy density of the second laser is 0.5–8.5 J / cm². 2 The duration of action of the second laser per unit area is 0.05–0.15 s / cm. 2 .

[0015] As a further improvement of the present invention, the first laser and the second laser process the adhesive film sequentially, or the first laser and the second laser process the adhesive film simultaneously.

[0016] As a further improvement of the present invention, the adhesive film is heat-sealed EVA, POE or EPE; and / or, the photovoltaic module is a double-glass photovoltaic module.

[0017] As a further improvement of the present invention, the adhesive films on the front and back of the photovoltaic module are processed by a first laser to form a light absorption layer on the adhesive film; and the adhesive film is thermally processed by a second laser to reduce the adhesive film's stickiness.

[0018] As a further improvement of the present invention, a first laser is used to process the photovoltaic module to form a light-absorbing layer on the adhesive film; a second laser is used to thermally process the adhesive film to reduce its adhesiveness; and a mechanical force is used to separate the adhesive film from the glass.

[0019] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0020] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0021] The laser processing method for recycling photovoltaic modules provided by this invention involves processing a light-absorbing layer on an adhesive film using a first laser. During a second laser treatment, the adhesive film absorbs a large amount of heat, causing the molecular bonds of the film material to break and deactivate. The adhesive film material loses its adhesiveness regardless of whether it is at high temperature or at room temperature, thus easily achieving separation from the glass. This method can effectively process different types of adhesive film encapsulation materials, achieving the separation of the adhesive film from the glass.

[0022] The laser processing method for recycling photovoltaic modules provided by the present invention forms a light absorption layer on the adhesive film by processing it with a first laser, thereby enhancing the absorption of the second laser and significantly increasing the utilization rate of the laser. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the laser processing method for recycling photovoltaic modules according to the present invention, in which the first laser and the second laser process the modules sequentially at two different workstations.

[0025] Figure 2 This is a schematic diagram of the laser processing method for recycling photovoltaic modules according to the present invention, in which the first laser and the second laser process simultaneously at the same workstation.

[0026] Figure 3 This is a photograph of a light-absorbing layer formed on the encapsulant film of a photovoltaic module after laser processing with a first laser of different energy densities in the laser processing method for recycling photovoltaic modules of the present invention.

[0027] Figure 4 yes Figure 3 The rightmost dotted line indicates the first laser-processed film micrograph;

[0028] Figure 5This is a photograph of the photovoltaic module recycling laser processing method of the present invention after the adhesive film is thermally processed by a second laser. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] On the one hand, the present invention provides a laser processing method for recycling photovoltaic modules, which uses a first laser to process the photovoltaic module to form a light absorption layer on the adhesive film, and uses a second laser to thermally process the adhesive film to reduce or even lose the adhesiveness of the adhesive film, so as to achieve the separation of the adhesive film and glass of the photovoltaic module.

[0031] Specifically, the first laser processing of the photovoltaic module aims to form a light-absorbing layer on the encapsulant film, enhancing its absorption by the second laser. Specifically, the first laser acts on the encapsulant film, causing physical and / or chemical changes. For example, the encapsulant film may absorb the energy of the first laser, altering its molecular structure and producing chromophores, resulting in a color change in the encapsulant film.

[0032] The second laser is designed to heat-treat the adhesive film, reducing or even eliminating its adhesiveness, thus loosening the bond between the film and the glass. This allows the film to be separated from the glass, or it can be separated from the glass by mechanical force.

[0033] In short, by using the method of the present invention, a first laser is used to create a light-absorbing layer on the adhesive film, which enhances the absorption of the second laser. The thermal effect of the second laser reduces the adhesive strength of the adhesive film, thus separating the adhesive film from the glass, or separating the adhesive film from the glass by mechanical force.

[0034] In this invention, a first laser and a second laser process the encapsulant film through the glass of the photovoltaic module. The photovoltaic module is preferably a double-glass photovoltaic module. The encapsulant film refers to heat-sealed EVA, POE, or EPE, etc.

[0035] Existing technologies use continuous infrared laser processing, but due to the transparency of the adhesive film, its absorption rate of the laser is low. Among existing EVA, POE, or EPE adhesive films, only EVA has a low melting point and can undergo endothermic melting under continuous infrared laser treatment, thereby reducing its viscosity and separating from the glass at high temperatures. EPE and POE have high melting points and cannot be melted by continuous infrared laser processing; their high viscosity prevents separation from the glass. Unlike existing technologies, this invention uses a first laser and a second laser for processing. Different types of adhesive films form a light-absorbing layer after the first laser processing. After the second laser processing, the molecular structure of the adhesive film changes, resulting in carbonization and complete loss of viscosity. Even after cooling to room temperature, the viscosity will not be restored. Therefore, this invention can reduce the viscosity of different types of adhesive films, thereby separating the adhesive film from the glass.

[0036] It should be noted that for double-glass photovoltaic modules, the encapsulant film on both sides needs to be processed by the first laser and the second laser. Specifically, the first laser and the second laser can be processed on the front and back encapsulant films of the photovoltaic module sequentially or simultaneously. This can reduce or even eliminate the adhesiveness of the encapsulant film on both sides of the cell, thus separating the encapsulant film from the glass, or separating the encapsulant film from the glass by mechanical force.

[0037] The laser processing method for recycling photovoltaic modules of the present invention uses a pulsed laser as the first laser, preferably a short-pulse-width pulsed laser, which rapidly applies energy to the adhesive film, easily forming a light-absorbing layer. Specifically, it is a femtosecond laser, picosecond laser, or nanosecond laser with a pulse width of less than 100 ns. The wavelength of the first laser is 355–1064 nm, preferably 532 nm or 1064 nm. Preferably, the focal point of the first laser is located near the surface of the adhesive film close to the glass or inside the adhesive film, forming a light-absorbing layer there. This enhances the absorption of the second laser, and since the adhesive film has already undergone chemical / physical changes under the action of the first laser, the molecular structure changes under the action of the second laser, making it prone to losing its adhesiveness. Furthermore, the adhesiveness is not expected to return after returning to room temperature, which is beneficial for separation from the glass.

[0038] After the first laser processing, the color of the adhesive film turns yellow, black, or white.

[0039] In the laser processing method for recycling photovoltaic modules of the present invention, the second laser is preferably a wide-pulse-width laser or a continuous laser. For example, it is a pulsed laser with a pulse width greater than 150 ns or a continuous laser. Preferably, the second laser is an infrared laser with a wavelength of 1064 nm. By continuously applying the infrared laser to the adhesive film, a thermal effect is generated, which promotes the aging and deactivation of the adhesive film, causing it to lose its adhesiveness and facilitating the separation of the adhesive film from the glass.

[0040] The first laser of this invention employs a short-pulse laser, which features high peak power and instantaneous processing. It can act solely on the material surface, and the high peak power can modify the adhesive film, increasing its absorption by the second laser. The second laser, employing a wide-pulse laser or a continuous laser, has a longer duration of action, causing the adhesive film to absorb heat and undergo a chemical change, losing its adhesiveness and facilitating its separation from the glass.

[0041] The laser processing method for recycling photovoltaic modules of the present invention involves a first laser beam covering the entire surface of the adhesive film, forming a light-absorbing layer across the entire film. This allows the entire film to effectively absorb the second laser beam, reducing its adhesion through the thermal effect of the second laser. In other embodiments, the area affected by the first laser beam can be a portion of the film surface, for example, a regularly or irregularly shaped pattern, such as a dot matrix, linear array, concentric circles, or an S-shape. The light-absorbing layer formed at the location of the first laser beam provides good absorption of the second laser beam, generating a good thermal effect and diffusing to surrounding areas not affected by the first laser beam, thus reducing the film's adhesiveness. However, the area affected by the first laser beam should be relatively large, and the spacing between these areas should not be too large, so that mechanical separation can be easily achieved even if adhesive areas exist outside the affected areas during subsequent separation. For example, the area affected by the first laser beam should be no less than 90% of the entire film surface, and the distance between adjacent areas should not exceed 0.6–0.8 mm.

[0042] The preferred location for the second laser to act is the entire surface of the adhesive film. This surface scanning of the entire film surface by the second laser not only accelerates the processing efficiency but also ensures the effective heating of the entire surface. In other embodiments, the area acted by the second laser can be the same portion of the adhesive film surface where the first laser acts.

[0043] It should be noted that in photovoltaic modules, the solar cells are not fully laid on the glass. Those skilled in the art know that there are gaps between adjacent solar cells, and there are no solar cells at the edges of the module / glass. The preferred sequence of the first laser treatment is to start from the edge of the module / encapsulant film and move towards the solar cell area, i.e., from the edge to the center. Since the first laser treatment of the encapsulant film generates gas, the expansion of this gas poses a risk of shattering the glass. Therefore, starting the treatment from the edge of the encapsulant film reduces the risk of glass breakage and improves the recycling efficiency of photovoltaic module materials.

[0044] The laser processing method for recycling photovoltaic modules of the present invention includes, prior to the laser processing, the step of removing the aluminum frame and junction box of the photovoltaic cell and photovoltaic module.

[0045] After the laser treatment described above, if the adhesive film loses its adhesiveness, it can be directly separated from the glass. However, the adhesive film may not have completely lost its adhesiveness. Therefore, after laser treatment, a step is included to separate the adhesive film and glass using mechanical force, such as by mechanically pulling them apart. Following this step, the solar cells and adhesive film are separated by mechanical force, or other methods are used to separate them. Finally, a step is included to classify and recycle the separated solar cells, photovoltaic module glass, and photovoltaic adhesive film.

[0046] The energy density of the first laser is 0.75–8.4 J / cm². 2 The energy density of the second laser is 0.5–8.5 J / cm². 2 The duration of action of the second laser per unit area is 0.05–0.15 s / cm. 2 As will be understood by those skilled in the art, under the condition of satisfying energy density, the larger the spot size of the first laser and the spot size of the second laser, the higher the processing efficiency. Preferably, the spot size of the first laser is 25-500 μm, and the spot size of the second laser is 250-5000 μm, and the spot size of the second laser is 250-5000 μm, and the spot size of the second laser is 250-5000 μm.

[0047] In some embodiments, the first laser of the present invention is an infrared picosecond laser with a frequency of 500–2000 kHz and a laser energy density of 1.7–8.4 J / cm². 2 The laser spot size is 25–150 μm, the laser scanning speed is 4.5–22.5 m / s, and the number of scans is 1.

[0048] In some embodiments, the first laser of the present invention is a green picosecond laser with a wavelength of 532 nm, a frequency of 200-1000 kHz, and a laser energy density of 0.9-5.4 J / cm². 2 The laser spot size is 25–150 μm, the scanning speed is 18–45 m / s, and the number of scans is 1.

[0049] In some embodiments, the first laser of the present invention is an ultraviolet picosecond laser with a wavelength of 355 nm, a frequency of 200-1000 kHz, and a laser energy density of 0.75-4.9 J / cm². 2 The spot size is 25–150 μm, the scanning speed is 8–30 m / s, and the number of scans is 1.

[0050] In some embodiments, the second laser is an infrared continuous laser with a laser energy density of 0.9–1.8 J / cm². 2 The spot size is 250–1100 μm, the laser scanning speed is 5–25 m / s, and the interaction time per unit area is 0.05–0.15 s / cm. 2 The number of scans is 5 to 20.

[0051] In some embodiments, the second laser is an infrared pulsed laser with a frequency of 20–100 kHz and a laser energy density of 4.0–8.5 J / cm². 2 The spot size is 250–1100 μm, the scanning speed is 6–12.5 m / s, and the interaction time per unit area is 0.05–0.15 s / cm. 2 The number of scans is 5 to 20.

[0052] When using pulsed lasers, specifically, when the pulse width is less than 100 ns, the high energy and power density of the single pulse are sufficient to strip the outer electrons of the material. Energy can be injected extremely quickly into a very small area, and this instantaneous high-energy-density deposition alters the electron absorption and movement patterns, significantly reducing the effects of linear laser absorption, energy transfer, and diffusion. This fundamentally changes the physicochemical properties of the material, creating a light-absorbing layer. When using pulsed lasers with a pulse width greater than 150 ns, the material is subjected to prolonged laser thermal effects, resulting primarily in thermal effects. Therefore, for pulsed lasers, a pulse width less than 100 ns is selected as the first laser, and a pulse width greater than 150 ns is selected as the second laser.

[0053] It should be noted that the time of action per unit area of ​​the second laser refers to the total time of action per unit area. For example, when scanning 5 times, it is the sum of the 5 times of action per unit area. For instance, the time of action is the same whether the laser scans once at speed A or scans twice at speed 2A.

[0054] It should be noted that the laser spot can be a circular spot or a square spot, etc. When the spot is circular, the spot size refers to the spot diameter; when the spot is square, the spot size refers to the side length; and when the spot is strip-shaped, the spot size refers to the length of the long side.

[0055] The laser processing method for recycling photovoltaic modules of the present invention allows for sequential execution of the first and second laser processing. Specifically, the entire encapsulant film can be processed first using the first laser, followed by the second laser processing. Alternatively, the first and second laser processing can be performed sequentially on the entire encapsulant film; for example, both the first and second lasers can scan the film, with the first laser scanning the same location before the second. It should be noted that the first and second laser processing can also be performed simultaneously. That is, the first and second lasers simultaneously scan the same location on the encapsulant film for processing.

[0056] In practice, the photovoltaic module is placed on a support platform. A first laser scans the encapsulant film at the first station, and then a second laser scans the film. Alternatively, the first laser scans the film at the first station, then the photovoltaic module is transferred to a second station, where the second laser scans the film. See also... Figure 1 , Figure 1 The diagram shows the first and second laser processing processes being performed sequentially at two different workstations.

[0057] Alternatively, the photovoltaic module is placed on a support platform, with the first and second lasers positioned above the platform and offset from each other. The first and second lasers can be moved, or the support platform can be moved, so that the first and second lasers move relative to the photovoltaic module, while maintaining the first laser ahead of the second laser. In this case, the device for the first and second lasers can be configured to include a first laser, a second laser, a galvanometer, and a field lens, wherein the galvanometer is a single-wavelength or dual-wavelength galvanometer, and the field lens is a single-wavelength or dual-wavelength field lens. Those skilled in the art will understand that when both the first and second lasers are infrared lasers, a single-wavelength galvanometer and a single-wavelength field lens can be used; when the first laser is a non-infrared laser, a corresponding dual-wavelength galvanometer and a dual-wavelength field lens can be used.

[0058] Alternatively, the photovoltaic module is placed on a support platform, with the first and second lasers positioned above the platform and coaxially aligned. Moving the first and second lasers, or moving the support platform, relative to the photovoltaic module allows for simultaneous processing. In this configuration, the second and first lasers are emitted coaxially, and the emission time of both lasers is controlled by the same galvanometer. See also... Figure 2 , Figure 2 A schematic diagram is provided showing the simultaneous processing of the first and second lasers at the same workstation. Using this method, the processing time can be reduced by approximately 20%. Simultaneously, heat loss during processing is reduced, thus the energy required for the second laser can be lowered by about 5-10%.

[0059] By adopting the second and third methods, the overall processing time is reduced and the production capacity is increased. Furthermore, the first laser processing of the adhesive film has a preheating effect, and the laser energy and number of processing steps required for the second laser heat treatment can be reduced.

[0060] To make the technical solution of the present invention clearer, specific embodiments are described in detail below.

[0061] Example 1

[0062] The double-glass TOPCon solar photovoltaic module has semi-tempered patterned glass on both sides with a thickness of 2mm, and the upper and lower films are made of EPE material with a thickness of 250μm.

[0063] The first laser is used to process the encapsulant film of the photovoltaic module to form a light-absorbing layer on the encapsulant film.

[0064] The first laser scan uses a 1064nm infrared picosecond laser to scan the photovoltaic module. The laser pulse width is 10ps, the frequency is 500-2000kHz, and the laser energy density is 1.7-8.4J / cm². 2 The laser spot size is 25-65μm, the laser scanning speed is 4.5-22.5m / s, covering the entire photovoltaic module area, and the scanning number is 1. After the scanning is completed, the color of the EPE film changes from transparent to yellow, black or white.

[0065] See Figure 3 , Figure 3 This image shows the formation of a light-absorbing layer on the encapsulant film of a photovoltaic module after laser processing with first lasers of different energy densities. The red dashed lines in the image indicate the results after laser processing with four different energy densities. From right to left, as the cumulative energy density of the first laser increases, the color of the encapsulant film changes to varying degrees. Due to the plasma shielding effect generated by the first laser processing of the encapsulant film, the actual focal point of the laser keeps shifting towards the glass surface. When the laser processing energy is too high, it creates an internal engraving effect on the glass; therefore, the white appearance is due to scratches on the glass.

[0066] See Figure 4 , Figure 4 for Figure 3 In the image, the rightmost dashed line indicates a micrograph of the film after the first laser treatment. The image clearly shows a significant discoloration of the film.

[0067] A second laser is used to thermally process the adhesive film, reducing its adhesion or even eliminating it, so as to separate the adhesive film from the glass of the photovoltaic module.

[0068] The second laser uses a continuous infrared laser to scan the photovoltaic module, with a laser energy density of 0.9–1.8 J / cm². 2 The laser spot size is 1.1 mm, the laser scanning speed is 15–30 m / s, covering the entire photovoltaic module area, and the number of scans is 5–20. For example, the first laser processing forms a yellow light-absorbing layer, preferably with 15–20 scans; the first laser processing forms a black light-absorbing layer, preferably with 5–10 scans. As the number of laser scans increases (the irradiation time per unit area increases), delamination between the glass and the encapsulant film becomes visible to the naked eye.

[0069] See Figure 5 , Figure 5 This is a photograph taken after the film and glass are separated following thermal processing of the light-absorbing layer using a second laser.

[0070] In this embodiment, the front and back films of the photovoltaic module are subjected to first laser processing and second laser processing, respectively.

[0071] Then, mechanical force is used to separate the adhesive film from the glass.

[0072] After the photovoltaic module cools down to room temperature, the glass and the encapsulant film are separated by a scraper, or the lower surface of the photovoltaic module is fixed and the upper surface is adsorbed, and then the glass and the encapsulant film are separated by lifting, twisting or other methods.

[0073] Example 2

[0074] This embodiment is otherwise the same as Embodiment 1, except that the first laser is green light with a wavelength of 532nm, a frequency of 500kHz, and a laser energy density of 4.5J / cm². 2 The spot size is 150μm and the scanning speed is 35m / s.

[0075] Example 3

[0076] This embodiment is otherwise the same as Embodiment 1, except that the first laser is ultraviolet with a wavelength of 355nm, a frequency of 200kHz, and a laser energy density of 3.75J / cm². 2 The spot size is 110μm and the scanning speed is 11m / s.

[0077] Example 4

[0078] The rest of this embodiment is the same as that of embodiment 1, except that the first laser processing position is a dot matrix, the first laser action area is not less than 90% of the entire area, and the distance between adjacent first laser action areas does not exceed 0.6 to 0.8 mm.

[0079] The results show that Examples 1 to 4 all reduced the adhesiveness of the film, allowing the glass and the film to separate directly, or the film and glass to be separated by mechanical force.

[0080] Comparative Example 1

[0081] The double-glass TOPCon solar photovoltaic module has semi-tempered patterned glass on both sides with a thickness of 2mm. Both the upper and lower films are made of EPE material, and the thickness after lamination is 250μm.

[0082] The difference from Example 1 is that the first laser processing is not performed, but the second laser processing is performed directly. The rest is the same as Example 1, and it was found that the adhesive film did not lose its adhesiveness.

[0083] The method of this invention solves the problem that some adhesive film materials, such as EPE and POE, are too sticky to be separated when only infrared continuous laser heat treatment is used. By using the action of the first laser and the second laser, the purpose of separating glass and adhesive film is achieved.

[0084] The method of this invention uses a first laser to process a light-absorbing layer on a high-transmittance adhesive film, which increases the absorption of the adhesive film by the second laser and reduces the power of the second laser heat treatment, thereby achieving the purpose of cost reduction and efficiency improvement.

[0085] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser processing method for recycling photovoltaic modules, characterized in that: The method includes using a first laser to process the photovoltaic module and form a light-absorbing layer on the adhesive film; and using a second laser to thermally process the adhesive film to reduce its stickiness.

2. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The method of using a first laser to process the photovoltaic module and form a light-absorbing layer on the encapsulant film is as follows: the first laser is used to process the encapsulant film of the photovoltaic module, causing the encapsulant film to change color.

3. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The first laser is a picosecond laser, a femtosecond laser, or a nanosecond laser with a pulse width of less than 100 ns.

4. The laser processing method for recycling photovoltaic modules according to claim 3, characterized in that: The wavelength of the first laser is 355–1064 nm, and / or, The energy density of the first laser is 0.75–8.4 J / cm². 2 .

5. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The focal point of the first laser is located on the surface of the adhesive film near the glass side, or inside the adhesive film on that side.

6. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The first laser processing area is either the entire surface of the photovoltaic module or a portion thereof.

7. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The scanning sequence of the first laser is from the edge of the film to the middle.

8. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The second laser is a continuous infrared laser, or a pulsed infrared laser with a pulse width greater than 150 ns.

9. The laser processing method for recycling photovoltaic modules according to claim 8, characterized in that: The energy density of the second laser is 0.5–8.5 J / cm². 2 The duration of action of the second laser per unit area is 0.05–0.15 s / cm. 2 .

10. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The first laser and the second laser process the adhesive film sequentially, or the first laser and the second laser process the adhesive film simultaneously.

11. The laser processing method for recycling photovoltaic modules according to claim 1, characterized in that: The adhesive film is heat-sealed EVA, POE, or EPE; and / or, The photovoltaic module is a double-glass photovoltaic module.

12. The laser processing method for recycling photovoltaic modules according to claim 11, characterized in that: Simultaneously, the encapsulant film on the front and back of the photovoltaic module is processed by a first laser to form a light absorption layer on the encapsulant film; a second laser is used to thermally process the encapsulant film to reduce its stickiness.

13. A laser processing method for recycling photovoltaic modules according to any one of claims 1 to 12, characterized in that: The photovoltaic module is processed using a first laser to form a light-absorbing layer on the adhesive film; the adhesive film is then thermally processed using a second laser to reduce its adhesiveness, and the process also includes a step of separating the adhesive film from the glass using mechanical force.

Images