The method for highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device
The laser-based method efficiently separates and recovers high-purity silicon from photovoltaic panels by vaporizing polymer foils and separating silicon fragments, addressing the inefficiencies of existing technologies and ensuring high yield and purity.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SLOVENSKA TECHNICKA UNIVERZITA V BRATISLAVE
- Filing Date
- 2025-11-27
- Publication Date
- 2026-06-18
Smart Images
Figure SK2025050010_18062026_PF_FP_ABST
Abstract
Description
[0001] The method for highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device
[0002] Technical field
[0003] The invention relates to the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device for the purpose of recovery of silicon for its further use in production. The invention falls within the field of mechanical engineering, energy, and waste management.
[0004] Background
[0005] Photovoltaic technologies are currently on the rapid rise. In 2016, the International Renewable Energy Agency (IRENA) predicted that at the beginning of 2030, the number of decommissioned photovoltaic panels worldwide would be approximately 4% of the number of installed panels. The amount of waste from photovoltaic panels will increase to at least 5 million tons per year until 2050, reported the agency. The cumulative global value of raw materials that could technically be recovered from photovoltaic panels could reach 450 million USD (calculated for 2016), which roughly corresponds to the cost of raw materials needed to produce approximately 60 million new panels or 18 GW of production capacity. According to the report, the cumulative value of recoverable raw materials could exceed 5 billion USD until 2050.
[0006] The construction of photovoltaic panels is generally well known; the semiconductor layer is most commonly based on silicon alloyed with boron, phosphorus, gallium arsenide, or cadmium sulphide, and eventually metals such as In, Mo, Se, and Te. Titanium oxide or silicon oxide is used as an anti-reflective coating for the semiconductor layer. Metals such as palladium, silver, nickel, copper, and tin-plated copper are used to create contacts. AVA and EVE polymer foils and other suitable materials are used to separate the individual layers. The front covering layer is usually made of glass or plastic. The rear supporting layer cover is made of plastic or metal treated with a Mylar or Tedlar coating. Photovoltaic panels are globally considered as a valuable tool in reducing carbon emissions, but during their operation they gradually degrade and become less efficient. After a certain period of time, even if they are still fully functional, it is even more cost-effective to replace them with new ones.
[0007] This creates the problem of disposing of morally and physically worn-out photovoltaic panels and destructively damaged photovoltaic panels. Silicon production has a growing importance in the global context, and it is necessary to focus on the possibility of recycling it from photovoltaic panels so that the recovered silicon can be used as a raw material for the remanufacturing of new photovoltaic panels and rechargeable batteries.
[0008] The recycling of photovoltaic panels is divided into three main stages: stratification, decomposition of individual materials, separation, extraction, and cleaning of materials. Solar panels are recycled primarily through chemical, thermal, and mechanical processes. The process begins with the removal of junction boxes, wires, and frames. There are many technologies in which the entire panels are crushed and then the individual waste materials are sorted and separated. The separation of materials allows them to be sent to the specific recycling process for the recovery of the secondary raw material. This process applies to crystalline silicon panels.
[0009] SOLAR 4.0 photovoltaic panel recycling technology is based on the removal of metal frames, followed by disintegration - crushing and removal of the glass layer in the form of glass powder. This is followed by the joint crushing of the semiconductor layer, polymer layers, and plastic base layer. The mixed crushed material then passes through a series of separators, where plastics, metals, and silicon-containing semiconductor fragments are separated.
[0010] The SUNY GROUP'S photovoltaic panel recycling technology is based on the removal of metal frames followed by the crushing of the entire panel, i.e., the glass layer, semiconductor layer, polymer layers, and plastic base layer together. The mixed crushed material then passes through a series of separators, where glass, plastics, metals, and silicon-containing semiconductor fragments are separated.
[0011] There is a technology for recycling solar photovoltaic panels where the metal frames, which are 100% recyclable, are separated. The glass is separated from the solar panels and is 95% recyclable. The remaining material from the solar panels is heated to over 450°C. This evaporates the plastic material, which can then be used as a heat source in further processing. Chemical etching is then used to isolate the silicon components, which can be melted down, and 85% of the silicon can be recycled.
[0012] There is also the technology of recycling solar panels, where after removing of the solid glass and aluminum frame, a smaller conductive part called the wafer, sealed in polymer, remains for recycling. The wafer contains silver, silicon, tin, and zinc. This technology does not separate the metals from the wafer, but shavings from aluminum machining are added to the crushed wafer. Two types of waste from different sources are pressed into aluminum pellets, which can be used in foundry production because all the metals contained in the wafers can be used in the right proportion with aluminum to improve the properties of aluminum alloys. The above-mentioned shortcomings evoked the proposal for a different system that would eliminate the shortcomings of the state of the art.
[0013] The result of efforts to meet the condition of preserving of the original physical properties of silicon so that recycled silicon could be used for the same purpose is further described the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device in the presented invention.
[0014] Summary of the invention
[0015] The above-mentioned shortcomings are eliminated by a highly effective method of decomposing of the silicon semiconductor layer from photovoltaic panels according to the invention, which is preceded by a technological modification of photovoltaic panels, where they are stripped of electronic accessories and frames using already known technological procedures.
[0016] For this method, the photovoltaic panels are also stripped of their glass layer. Photovoltaic panels pre-processed in this way consist of sheets containing only the protective polymer foil, the semiconductor silicon layer, the base polymer foil, and the carrier, which is usually plastic, and are the input for the method of highly efficient decomposition of the silicon semiconductor layer from the photovoltaic panel sheets according to the presented invention. The essence of the invention is based on the fact that, in the first step, the covering polymer foil, semiconductor silicon layer, and base polymer foil are placed on the carrier of photovoltaic panel and advantageously continuously exposed in the laser module to the action of the laser beam from at least one laser head. It is preferable, if the laser beam is pulsed with frequency at least of 130 kHz and pulse length at least of 250 ns and has energy maximum of 0.05 mJ / cm2.
[0017] Subsequently, under the influence of the thermal energy of the laser beam, the covering polymer foil and the base polymer foil are vaporized, and the silicon fragments, together with the metal interconnecting wires of the semiconductor silicon layer, are released from the carrier of photovoltaic panel. When applying the laser beam to the covering polymer foil, semiconductor silicon layer, and base polymer foil, the vapour from the covering polymer foil and base polymer foil is captured by the exhaust device. In the second step, the released silicon fragments and metal interconnecting wires are separated from each other in the separating module.
[0018] The method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels is carried out on the decomposition device, the essence of which is that it contains the laser module with the industrial laser and the laser head, the sliding mechanism for changing of relative position of the photovoltaic plate and the laser module head, the exhaust device for capturing of vapours from the covering polymer foil and the base polymer foil, and the separating module for separation of released silicon fragments from the metal interconnecting wires.
[0019] The sliding mechanism for changing of relative position of the photovoltaic plate and the head of the laser module is the input conveyor of photovoltaic panels or the sliding mechanism of the head of the laser module.
[0020] It is possible for the laser head to have the flat beam output. It is possible to place the output conveyor in front of the separating module to remove the released silicon fragments and metal interconnecting wires. It is preferable if the laser module contains the industrial pulsed laser with frequency minimally 130 kHz and pulse length minimally 250 ns and laser beam energy maximally 0.05 mM / cm2.
[0021] In order to remove the glass layer from photovoltaic panels, the glass delamination module with the glass fragment storage container is placed in front of the decomposition device for decomposing of the silicon semiconductor layer from photovoltaic panels. The decomposition device is functional when the movement of the photovoltaic panel sheets is vertical, horizontal, or inclined.
[0022] The advantages of the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device according to the invention are evident from its effects, which are manifested externally. The effects consist in the fact that, on the one hand, the criteria of high processing efficiency and affordability are met and, on the other hand, the possibility of maximum yield and purity of individual fragments of secondary raw materials obtained is fulfilled. One significant advantage is that only dry technology is used for decomposition, where the output of decomposition is pure silicon fragments and also fragments of metal interconnecting wires, e.g. Ag, Cu. Only the whole sheet of the lower plastic carrier of photovoltaic panel comes out of the decomposition device.
[0023] Overview of figures on the drawings
[0024] The method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels and the decomposition device according to the invention will be further explained in the figures, in which:
[0025] Fig. 1 shows the block diagram of the decomposition device of the silicon semiconductor layer from photovoltaic panels in horizontal arrangement, which also shows the decomposition method. Fig. 2 shows the block diagram of the decomposition device of the silicon semiconductor layer from photovoltaic panels in vertical arrangement, which also shows the decomposition method.
[0026] Fig. 3 shows the decomposition device of the silicon semiconductor layer from photovoltaic panels in inclined arrangement supplemented by glass delamination.
[0027] Examples
[0028] It is understood that the individual embodiments of the invention are presented for illustration and not as limitations on the solutions. Those skilled in the art will find or be able to discover, using no more than routine experimentation, many equivalents to the specific embodiments of the invention. Such equivalents will also fall within the scope of the patent claims.
[0029] Example 1
[0030] This example of the specific embodiment describes the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to the invention. The input for decomposition is only the plastic carrier sheet C of photovoltaic panel with base polymer film B, semiconductor silicon layer A, and covering polymer film D. In the first step, the covering polymer foil D, the semiconductor silicon layer A, and the base polymer foil B are placed on the plastic carrier C of photovoltaic panel in the laser module 1 by the input conveyor 2, continuously moved in horizontal position, and exposed to the laser beam from the laser head. The laser beam is pulsed with frequency 143 kHz and pulse length 350 ns, and has energy 0.045 mJ / cm2. Subsequently, under the influence of the thermal energy of the laser beam, the covering polymer foil D and the base polymer foil B are evaporated, and the silicon fragments Ai, together with the metal connecting wires A2 of the semiconductor silicon layer, are released from the plastic base carrier C of photovoltaic panel and fall onto the output conveyor 5. When the laser beam is applied to the covering polymer foil D, the semiconductor silicon layer A, and the base polymer foil B, the vapours from the covering polymer foil D and the base polymer foil B are captured by the exhaust device. In the second step, the released and collected silicon fragments Al and metal interconnecting wires A2 are separated from each other in the separating module 3, as shown in Fig. 1.
[0031] Similarly, it is possible to move the head of the laser module 1, and this method can also be used for vertical or inclined movement of the processed modified photovoltaic panel sheet, as shown in Fig. 2. Example 2
[0032] This example of the specific embodiment describes the essential part of the decomposition device in horizontal arrangement, on which the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to the invention is carried out, as shown in Fig. 1. It comprises the laser module 1 with the industrial laser and the laser head, the sliding mechanism for changing of relative position of the photovoltaic plate and the head of the laser module 1, which is the input conveyor 5.
[0033] The laser module 1 contains the industrial pulsed laser PULSAR SHARK II P CL 300M with maximum energy 1.8 mJ, frequency 143 kHz, pulse length 350 ns, and laser beam energy 0.045 mJ / cm2. Laser head 1 has the output flat laser beam with the area 200 x 20 mm.
[0034] It further comprises the exhaust device 4 for capturing of vapours from covering polymeric foil D and base polymeric foil B. Finally, it comprises the separating module 3 for separation of released fragments Ai of silicon from metal interconnecting wires A2.
[0035] The analogous solution is the decomposition device in vertical arrangement according to the invention, as shown in Fig. 2. It is essentially sufficiently described above. Analogously, it is possible to use the sliding mechanism for the head of the laser module 1.
[0036] Example 3
[0037] This example of the specific embodiment describes the essential part of the decomposition device in inclined arrangement, on which the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to the invention is carried out, as shown in Fig. 3. It includes the laser module 1, which has the laser head. The laser module 1 includes the industrial pulsed laser PULSAR SHARK II P CL 300M with frequency 143 kHz and pulse length 350 ns and laser beam energy max. 0.045 mJ / cm2. The part of the decomposition device also includes the input conveyor 2 for pre-prepared photovoltaic panel sheets and the exhaust device 4 for capturing of vapours from the covering polymer foil D and the base polymer foil B. At the output of the decomposition device, there is the output conveyor 5 and the separating module 3 for separation of silicon fragments Al from metal interconnecting wires A2.
[0038] For the purpose of removal of the glass layer from photovoltaic panels consisting of glass layer E, covering polymer film D, semiconductor silicon layer A, base polymer foil B, and plastic carrier C, glass delamination module 6 with storage tank 8 for glass fragments Ei is inserted in front of the decomposition device for decomposing of the silicon semiconductor layer from photovoltaic panels.
[0039] Industrial applicability
[0040] The method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to the invention is applicable in the field of solar energy and waste management.
[0041] List of related marks
[0042] 1 laser module
[0043] 2 input conveyor
[0044] 3 separating module
[0045] 4 exhaust device
[0046] 5 output conveyor
[0047] 6 glass delamination module
[0048] 7 glass fragment container
[0049] A semiconductor silicon layer
[0050] Ai silicon fragments
[0051] A2 metal interconnecting wires
[0052] B base polymer foil
[0053] C photovoltaic panel carrier
[0054] D polymer covering foil
[0055] E glass layer
[0056] Ei glass fragments
Claims
CLAIMS1. A method of highly efficient decomposition of a silicon semiconductor layer from photovoltaic panels stripped of electronic accessories, frames, and glass layer, characterized in that- in the first step, there is a covering polymer foil (D), a semiconductor silicon layer (A) and a base polymer foil (B) on a carrier (C) of photovoltaic panel in a laser module continuously exposed to a laser beam from at least one laser head, where subsequently, under an influence of a thermal energy of the laser beam, the covering polymer foil (D) and the base polymer foil (B) are evaporated and silicon fragments (Ai) together with metal interconnecting wires (A2) of the semiconductor silicon layer are released from the carrier (C) of photovoltaic panel, whereby when the laser beam is applied to the covering polymer foil (D), the semiconductor silicon layer (A) and the base polymer foil (B), a vapours of the covering polymer foil (D) and base polymer foil (B) are captured by an exhaust device (4);- in the second step, a released silicon fragments (Ai) are separated from the metal interconnecting wires (A2) in a separating module.
2. The method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to claim 1, characterized in that a laser beam is pulsed with frequency at least 130 kHz and pulse length at least 250 ns.
3. The method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to at least one of claims 1 and 2, characterized in that the laser beam has energy max. 0.05 mJ / cm2.
4. A decomposition device, which performs the method of highly efficient decomposition of the silicon semiconductor layer from photovoltaic panels according to the previous claims, characterized in that it comprises- a laser module (1) with an industrial laser and a laser head;- a sliding mechanism for changing of relative position of a photovoltaic plate and a head of the laser module (1);- the exhaust device (4) for capturing of vapours from the covering polymeric foil (D) and the base polymeric foil (B);- the separating module (3) for separation of the released silicon fragments (Ai) from the metal interconnecting wires (A2).
5. The decomposition device according to claim 4, characterized in that the laser module (1) comprises an industrial pulsed laser.
6. The decomposition device according to claims 4 and 5, characterized in that the industrial pulsed laser has frequency at least 130 kHz and pulse length at least 250 ns and laser beam energy max. 0.05 mJ / cm2.
7. The decomposition device according to at least one of claims 4 to 6, characterized in that an output conveyor (5) is included in front of the separating module (3) to remove the released silicon fragments (Ai) and metal interconnecting wires (A2).
8. The decomposition device according to any of the preceding claims 4 to 7, characterized in that a sliding mechanism for changing of relative position of a photovoltaic plate and the head of the laser module (1) is an input conveyor (2) of photovoltaic panels.
9. The decomposition device according to any of the preceding claims 4 to 7, characterized in that the sliding mechanism for changing of relative position of the photovoltaic plate and the head of the laser module (1) is the sliding mechanism of the head of the laser module (1).