CN111900222B - Recovery method of photovoltaic module - Google Patents

Abstract

The invention provides a photovoltaic component and a recovery method thereof. The photovoltaic module includes a first transparent substrate, a battery string and a second transparent substrate stacked in sequence, the battery string includes a plurality of battery sheets, and the battery sheets are connected through a connecting part, and the photovoltaic module also includes: a colloid part, at least partially located on the first transparent substrate Between the substrate and the connection part and between the second transparent substrate and the connection part are used to bond the battery string to the first transparent substrate and the second transparent substrate respectively; the sealing part is located between the first transparent substrate and the second transparent substrate The surrounding ends of the gap form a sealed cavity with the first transparent substrate and the second transparent substrate, and the sealing part is located in the sealed cavity. The above-mentioned colloid part can only be located between the connection part and the transparent substrate in the battery string, so as to facilitate the recycling of subsequent photovoltaic modules and help realize the harmless treatment of waste modules. The recycled materials are complete and of high purity, thereby reducing the environmental burden practical economic value.

Description

Recycling methods of photovoltaic modules

technical field

The invention relates to the field of photovoltaic technology, in particular to a photovoltaic module and a recycling method thereof.

Background technique

With the continuous improvement of the conversion efficiency of solar cells and modules, the rapid update and iteration of photovoltaic module technology has greatly reduced the system cost. Although the power reduction of photovoltaic modules with a design life of 25 years is still within the scope of the module company's warranty, due to the low initial power, today's 10-15 years later, from the perspective of power generation and economic efficiency, it may be The low-power components in some early large-scale ground power stations were scrapped ahead of time, and it was more cost-effective to reinstall high-power components. This poses the problem of recycling a large number of obsolete components. It is estimated that in the future, based on the annual processing capacity of photovoltaic modules of 50GW, about 3.5 million tons of waste modules will be generated every year. With such a huge amount, part of the supply of raw materials for photovoltaic cells in the future may come from the recycling of materials in photovoltaic modules.

At present, the recycling methods of photovoltaic modules mainly include organic or inorganic solvent dissolution method, thermal decomposition treatment method, physical crushing and separation method, etc., but these methods have certain limitations, or produce waste liquid and waste gas, which may cause environmental damage. Secondary pollution, or the inability to obtain high-purity recoveries. However, the current mainstream double-sided double-glass modules are more difficult to recycle, and it is difficult to obtain complete cells and glass.

The main reason why modules are so difficult to handle is that the packaging materials of photovoltaic modules are also designed for 25 years of long-term and reliable performance. When disposing of waste components, the adhesion between the packaging film and the batteries, metal interconnection strips, glass, backplane and other materials is too good, which is not conducive to the recycling of components. Therefore, designing a photovoltaic module that is easy to recycle and has a service life of 5 to 15 years is to meet the internal needs of the rapid iterative upgrading of the current industry, and it is conducive to the effective utilization and harmless treatment of materials in waste modules, thereby reducing the environmental burden , has potential practical economic value.

Contents of the invention

The main purpose of the present invention is to provide a photovoltaic module and a recycling method thereof, so as to solve the problem that the recycling of photovoltaic modules is difficult in the prior art.

In order to achieve the above object, according to one aspect of the present invention, a photovoltaic module is provided, including a first transparent substrate, a battery string and a second transparent substrate stacked in sequence, the battery string includes a plurality of battery sheets, and the battery sheets are connected through the connecting part. connection, the photovoltaic module also includes: a colloid part, at least partly located between the first transparent substrate and the connection part and between the second transparent substrate and the connection part, for bonding the battery string to the first transparent substrate and the second transparent substrate respectively The junction; the sealing part is located at the peripheral ends of the first transparent substrate and the second transparent substrate, and forms a sealed cavity with the first transparent substrate and the second transparent substrate, and the colloid part is located in a part of the sealed cavity.

Further, the connection part includes interconnection strips, the interconnection strips cover part of the front and back surfaces of each battery slice, and pass through each battery slice into an electrical path, and the gel part at least partially covers the interconnection strips and/or the battery slices.

Further, the connection part includes a conductive adhesive layer, and the ends of adjacent battery sheets are overlapped and bonded through the conductive adhesive layer to form an electrical path.

Further, the refractive index of the colloid part is 1.4 to 1.5, and the material forming the colloid part is preferably selected from ethylene-vinyl acetate copolymer, ethylene and α-olefin copolymer, polyvinyl butyral, ionomer, polyurethane and Any one or more of polysiloxanes.

Further, there are multiple battery strings, and the connection part also includes a bus bar connecting each battery string. The colloid part at least partially covers the bus bar. Preferably, the second transparent substrate is provided with a wiring lead-out hole, and the bus bar is drawn out to the sealed cavity through the wiring lead-out hole. Outside, the position of the lead-out hole is filled with the material of the colloidal part.

Further, the water vapor transmission rate of the material forming the sealing part is <0.1 g/m ² /day, preferably butyl rubber.

Further, the sealing portion has a width of 0.5 mm to 50 mm and a thickness of 0.5 mm to 7 mm.

Further, the sealed cavity is filled with a protective gas, preferably any one or more of nitrogen, argon, helium, neon and carbon dioxide.

Further, a ventilation hole is opened in the sealing part, and the photovoltaic module further includes a sealing plug disposed in the ventilation hole, preferably there are a plurality of ventilation holes, and the sealing plug in at least one ventilation hole is connected with an air pressure balance device.

Further, both the first transparent substrate and the second transparent substrate are glass substrates, and preferably a part of the surface of the second transparent substrate is coated with a reflective white glaze layer or pasted with a reflective film.

According to another aspect of the present invention, a method for recycling photovoltaic modules is provided, including the following steps: using the above-mentioned photovoltaic modules, thermally degrading the colloidal part and the sealing part in the photovoltaic module, so that the battery strings in the photovoltaic module Separated from the first transparent substrate and the second transparent substrate respectively.

Further, the step of thermally degrading the colloidal part and the sealing part in the photovoltaic module includes: opening a ventilation hole in the sealing part of the photovoltaic module, and passing heated gas into the sealing cavity through the ventilation hole to cool the colloidal part and the sealing part. The sealing part is thermally degraded, and the heating gas is preferably nitrogen or oxygen-containing gas.

Applying the technical solution of the present invention, a photovoltaic module is provided, including a sequentially stacked first transparent substrate, a battery string, and a first transparent substrate. The battery string includes a plurality of battery sheets, and there are multiple battery sheets connected by connecting parts. , the photovoltaic module also includes a colloid part, the colloid part is respectively located between the first transparent substrate and the connection part and between the second transparent substrate and the connection part, and is used to connect the battery string to the first transparent substrate and the second transparent substrate respectively . The above-mentioned colloid part can fix the battery string between the upper and lower transparent substrates, so that it will not move, and at the same time play a good role in cushioning and bonding, and has good reliability, which is consistent with the structure of the existing components; and, relatively Compared with the encapsulating adhesive film that is fully laid on the front and back of the battery sheet in the prior art, the above-mentioned colloidal part can only be located between the connecting part in the battery string and the transparent substrate (part of the surface of the battery sheet can also be covered with part of the colloidal part), so that A channel capable of accommodating the heating medium is formed in the sealed cavity between the upper and lower transparent substrates, and then the colloid part is thermally degraded through the above channel, which facilitates the subsequent recycling of photovoltaic modules and is conducive to the harmless treatment of waste modules, and the recycled materials are complete. And the purity is high, thereby reducing the environmental burden, and has potential practical economic value.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 shows a schematic diagram of a partial cross-sectional structure of a photovoltaic module provided according to an embodiment of the present invention;

Fig. 2 shows a partial cross-sectional structural schematic diagram of another photovoltaic module provided according to an embodiment of the present invention;

Fig. 3 shows a schematic top view of the cell string in the photovoltaic module shown in Fig. 1;

FIG. 4 shows a schematic top view of the cell string in the photovoltaic module shown in FIG. 2 .

10. First transparent substrate; 210. Cell sheet; 220. Interconnection strip; 230. Conductive adhesive layer; 240. Bus bar; 30. Second transparent substrate; 40. Colloid part; 50. Sealing part; 60. Wiring outlet ; 70, ventilation hole; 80, air pressure balance device.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It should be understood that the data so used may be interchanged under appropriate circumstances for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

As introduced in the background art, the encapsulation materials of photovoltaic modules are also designed according to the long-term and reliable performance of 25 years. When disposing of waste components, the adhesion between the packaging film and the batteries, metal interconnection strips, glass, backplane and other materials is too good, which is not conducive to the recycling of components.

In order to solve the above technical problems, the applicant of the present invention provides a photovoltaic module, as shown in Fig. 1 and Fig. A battery sheet 210, the battery sheet 210 is connected through the connection part, the photovoltaic module also includes a colloid part 40 and a sealing part 50, at least part of the colloid part 40 is located between the first transparent substrate 10 and the connection part and the second transparent substrate 30 Between the connection part, it is used to bond the battery string to the first transparent substrate 10 and the second transparent substrate 30 respectively; the sealing part 50 is located at the peripheral ends of the first transparent substrate 10 and the first transparent substrate 30, and is connected A sealed cavity is formed between the first transparent substrate 10 and the first transparent substrate 30, and the colloid part 40 is located in part of the sealed cavity.

The above-mentioned colloid part can fix the battery string between the upper and lower transparent substrates, so that it will not move, and at the same time play a good role in cushioning and bonding, and has good reliability, which is consistent with the structure of the existing components; and, relatively Compared with the encapsulating adhesive film that is fully laid on the front and back of the battery sheet in the prior art, the above-mentioned colloidal part can only be located between the connecting part in the battery string and the transparent substrate (part of the surface of the battery sheet can also be covered with part of the colloidal part), so that A channel capable of accommodating the heating medium is formed in the sealed cavity between the upper and lower transparent substrates, and then the colloid part is thermally degraded through the above channel, which facilitates the subsequent recycling of photovoltaic modules and is conducive to the harmless treatment of waste modules, and the recycled materials are complete. And the purity is high, thereby reducing the environmental burden, and has potential practical economic value.

In the above-mentioned photovoltaic module of the present invention, the connection part can realize the electrical connection between each cell sheet 210. In a preferred embodiment, the connection part includes an interconnection bar 220, and the interconnection bar 220 covers both sides of each cell sheet 210. On the surface of the side part, the colloid part 40 at least partially covers the interconnection bar 220 , as shown in FIG. 1 . At this time, the battery sheets 210 are arranged side by side without overlapping each other, as shown in FIG. 3 , and are electrically connected through interconnection strips 220 on the surface. The above-mentioned colloid part 40 can be laid longitudinally along the interconnecting strips 220 , or can be designed to be laid horizontally, as long as there are gas channels between the battery sheet 210 and the first transparent substrate 10 and the second transparent substrate 30 respectively.

In another preferred embodiment, the connection part includes a conductive adhesive layer 230 , and ends of adjacent battery sheets 210 are overlapped and bonded through the conductive adhesive layer 230 . At this time, the two ends of each battery slice 210 in a battery string are overlapped to form a shingled assembly, and each battery slice 210 is electrically connected through the conductive adhesive layer 230 at the overlapping position, as shown in FIG. 2 . For the shingled assembly in the prior art, the adjacent battery sheets are more likely to be broken by external force at the overlapping position, but the present invention covers at least part of the gel part 40 on the part of the battery surface corresponding to the overlapping position, which can Alleviate the effect of external force on the cell and reduce the risk of cell rupture due to external force.

In the above-mentioned photovoltaic module of the present invention, the first transparent substrate 10 and the second transparent substrate 30 can be glass substrates, wherein the second transparent substrate is preferably partially coated with a reflective white glaze layer or pasted with reflective strips, so as to obtain a glass-glass structure double glass components. For the double-glass module in the prior art, because the encapsulant is laid across the entire area between the two glass plates of the double-glass module to fix the cell in it, the area of the double-glass module that can contact the air is only around one The area of the circle is extremely small. At present, it can only be recycled by physically crushing the whole module. The final recyclables are all finely divided mixtures. It is difficult to screen and purify, and the cost is high, and it is impossible to obtain complete cells. However, the present invention reduces the coverage area between the two glass plates by making the colloidal part 40 only on the connection part and part of the battery sheet 210 surface, compared with the photovoltaic module in the prior art, and has a gas passage, which is beneficial The separation of the two glass plates is beneficial to the recycling of the batteries and metal materials.

When both the first transparent substrate 10 and the second transparent substrate 30 are glass substrates, preferably, the refractive index of the colloid part 40 is 1.4˜1.5. Since the colloid part 40 satisfying the above-mentioned refractive index can be close to the refractive index of glass, and not much different from that of the battery sheet, the optical loss can be effectively reduced.

The material forming the colloid portion 40 can be selected from ethylene-vinyl acetate copolymer (EVA), ethylene and α-olefin copolymer, polyvinyl butyral (PVB), ionomer, butyl rubber (PIB), Any one or more of polyurethane (TPU) and polysiloxane, preferably transparent materials in the above-mentioned types, but not limited to the above-mentioned types, those skilled in the art can form the above-mentioned colloid according to the required refractive index The type of part 40 is reasonably selected.

In order to ensure that the colloid part 40 can fix the cell 210 between the first transparent substrate 10 and the second transparent substrate 30 more stably, the thickness of the colloid part 40 is 0.2-3mm, and the cell has different busbar lines. , there are many kinds of sizes, those skilled in the art can set the colloidal part 40 with a reasonable area according to the actual type of cell, the colloidal part 40 can not be completely filled between the first transparent substrate 10 and the second transparent substrate 30, need to use A gas passage is left in the sealed cavity. Preferably, the colloid part 40 on each connecting part is strip-shaped, and the width of the colloid part 40 is 0.5-150 mm.

In the photovoltaic module of the present invention, there may be multiple battery strings. Preferably, the connection part further includes a bus bar 240 connecting each battery string, and the colloid part 40 at least partially covers the bus bar 240, as shown in FIGS. 3 and 4 . Show. By covering most or all of the bus bars 240 with the colloid part 40 , the covering area of the colloid part 40 on the cell sheet 210 can be reduced, thereby reducing the influence of the colloid part 40 on light.

Preferably, the second transparent substrate 30 is provided with a wire lead-out hole 60, and there is a colloid part 40 or a sealing part 50 between the wire lead-out hole 60 and the first transparent substrate 10 to ensure the airtightness of the component, and the bus bar 240 passes through the wire lead-out hole 60 Lead out to the outside of the sealed chamber. The above-mentioned bus bar 240 is used to connect with the junction box, the junction box and the second transparent substrate 30 can be bonded with silica gel, and the interior of the junction box is filled with potting glue. The wire lead-out hole 60 is filled with the material of the colloid part 40 , and the wire lead-out hole 60 may be further covered with the material of the sealing part 50 to ensure the airtightness of the assembly, as shown in FIGS. 3 and 4 .

In the photovoltaic module of the present invention, the first transparent substrate 10, the second transparent substrate 30 and the sealing part 50 together form a sealed cavity, and the battery string and the colloid part 40 are located in the sealed cavity. The width of the sealing part 50 can be 0.5- 50mm, the thickness can be 0.5~7mm. Preferably, the water vapor transmission rate of the material forming the sealing part 50 is <0.1 g/m ² /day, preferably butyl rubber. In the subsequent recycling process of photovoltaic modules, using the above-mentioned preferred materials can facilitate the separation of the first transparent substrate 10 and the second transparent substrate 30 through thermal degradation.

In the photovoltaic module of the present invention, preferably, the sealed cavity is filled with a protective gas, and the protective gas may be selected from any one or more of nitrogen, argon, helium, neon and carbon dioxide. Since the first transparent substrate 10 and the second transparent substrate 30 usually need to be evacuated to prevent water vapor from affecting the performance of the cell, however, this will cause the external pressure to be greater than the pressure inside the sealed cavity, so that the pressure during use The existence of the gap will still cause water vapor to enter the sealed cavity, but the present invention can balance the pressure inside and outside the sealed cavity by filling the sealed cavity with protective gas, and protect the cells in the sealed cavity from the influence of water vapor.

In order to better balance the pressure inside and outside the sealed cavity and to facilitate subsequent recovery, a ventilation hole 70 may be opened in the sealing part 50 , and the photovoltaic module further includes a sealing plug disposed in the ventilation hole 70 . More preferably, there are multiple ventilation holes 70, and the sealing plug in at least one ventilation hole 70 communicates with an air pressure balance device 80, which may be an air bag. The above-mentioned air pressure balance device 80 can also solve the problem of thermal expansion and contraction of gas in the photovoltaic module caused by changes in operating temperature during outdoor use.

According to another aspect of the present invention, there is also provided a method for recycling photovoltaic modules, including the following steps: using the above-mentioned photovoltaic modules provided by the present invention, thermally degrading the materials of the colloidal part 40 and the sealing part 50 in the photovoltaic module to The cell strings in the photovoltaic module are separated from the first transparent substrate 10 and the second transparent substrate 30 respectively.

In order to achieve thermal degradation of the materials of the colloidal part 40 and the sealing part 50 in the photovoltaic module, the photovoltaic module can be placed in a heating device, and the material of the colloidal part 40 and the sealing part 50 can be thermally degraded by the heating device. However, the current component recycling industry has not yet fully developed, and thermal degradation of organic materials is currently a relatively conventional method. However, for double-glass components, the gas cannot enter the interior of the component, and the component glass can only be broken and then thermally degraded. Materials such as complete glass and battery sheets cannot be obtained.

And the sealing part 50 in the above-mentioned photovoltaic module of the present invention can be provided with ventilating hole 70, can also pass into the sealing cavity through the venting hole 70 heating gas, is conducive to the accelerated degradation of the colloidal part 40 and the sealing part 50 material , to achieve complete material recovery. Re-open the ventilation holes 70 at various places, and heat at high temperature while introducing oxygen, nitrogen or air, so that the packaging materials that partially play a bonding and buffering role in the component can accelerate degradation, and finally obtain complete materials such as transparent substrates and battery sheets.

From the above description, it can be seen that the above-mentioned embodiments of the present invention have achieved the following technical effects:

1. The above-mentioned colloid part can fix the battery string between the upper and lower transparent substrates, so that it will not move, and at the same time play a good role in buffering and bonding, and has good reliability, which is consistent with the structure of the existing components;

2. Compared with the encapsulating adhesive film that is fully laid on the front and back of the battery sheet in the prior art, the above-mentioned colloid part is located between the connection part of the battery string, part of the battery surface and the transparent substrate, and in the sealed cavity between the upper and lower transparent substrates Form a channel capable of accommodating the heating medium, and thermally degrade the colloidal part and the sealing part through the above-mentioned channel, which facilitates the recycling of subsequent photovoltaic modules and is conducive to the harmless treatment of waste modules. The recycled materials are complete and of high purity, thereby reducing the environmental burden , has potential practical economic value.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A recycling method for photovoltaic modules, characterized in that, The photovoltaic module includes a first transparent substrate (10), a battery string and a second transparent substrate (30) stacked in sequence, the battery string includes a plurality of battery slices (210), and the battery slices (210) pass through the connection part connected, wherein the photovoltaic module also includes: A colloid part (40), at least partly located between the first transparent substrate (10) and the connection part and between the second transparent substrate (30) and the connection part, is used for connecting the battery string respectively bonded to the first transparent substrate (10) and the second transparent substrate (30); the connection part includes interconnection strips (220), and the interconnection strips (220) cover each of the battery sheets ( 210) on the front and back parts of the surface, each cell is strung into an electrical path, and the colloid part (40) at least partially covers the interconnection strip (220) and/or the cell (210); The sealing part (50) is located at the peripheral ends of the first transparent substrate (10) and the second transparent substrate (30), and is connected with the first transparent substrate (10) and the second transparent substrate ( 30) to form a sealed cavity, the colloid part (40) is located in part of the sealed cavity, and the material forming the colloid part (40) is selected from any one of ionic polymer, polyurethane and polysiloxane or more, the material forming the sealing part (50) is butyl rubber, and the material forming the colloid part (40) and the sealing part (50) can be thermally degraded under the action of a heating medium , wherein the heating medium is selected from oxygen or air; a ventilation hole (70) is opened in the sealing part (50), and the photovoltaic module further includes a sealing plug arranged in the ventilation hole (70), There are multiple air exchange holes (70), and the sealing plug in at least one air exchange hole (70) is connected with an air pressure balance device (80); The recycling method includes the following steps: thermally degrading the colloidal part (40) and the sealing part (50) in the photovoltaic module, so as to separate the battery strings in the photovoltaic module from the first The transparent substrate (10) is separated from the second transparent substrate (30); the step of thermally degrading the colloid part (40) and the sealing part (50) in the photovoltaic module includes: the photovoltaic module The air exchange hole (70) is opened in the sealing part (50), and the heating gas is introduced into the sealing cavity through the air exchange hole (70), so that the colloid part (40) and The sealing part (50) is thermally degraded, and the heating gas is nitrogen or oxygen-containing gas. 2. The recycling method of photovoltaic modules according to claim 1, characterized in that, the connection part comprises a conductive adhesive layer (230), and the ends of adjacent battery sheets (210) overlap and pass through the conductive glue layer (230). The glue layer (230) bonds and forms an electrical pathway. 3. The method for recycling photovoltaic modules according to claim 1 or 2, characterized in that the refractive index of the colloid part (40) is 1.4-1.5. 4. The recycling method of photovoltaic modules according to claim 1 or 2, characterized in that there are multiple battery strings, and the connection part further includes a bus bar (240) connecting each of the battery strings, the The colloid part (40) at least partially covers the bus bar (240), and the second transparent substrate (30) is provided with a wire lead-out hole (60), and the bus bar (240) passes through the wire lead-out hole (60) Lead out to the outside of the sealed cavity, and the position of the lead-out hole (60) is filled with the material of the colloid part (40). 5. The method for recycling photovoltaic modules according to claim 1 or 2, characterized in that the water vapor transmission rate of the material forming the sealing part (50) is <0.1 g/m ² /day. 6. The method for recycling photovoltaic modules according to claim 1 or 2, characterized in that, the width of the sealing part (50) is 0.5mm~50mm, and the thickness is 0.5mm~7mm. 7. The method for recycling photovoltaic modules according to claim 1 or 2, wherein the sealed cavity is filled with protective gas. 8. The method for recycling photovoltaic modules according to claim 7, wherein the protective gas is selected from any one or more of nitrogen, argon, helium, neon and carbon dioxide. 9. The method for recycling photovoltaic modules according to claim 1 or 2, characterized in that the first transparent substrate (10) and the second transparent substrate (30) are both glass substrates. 10 . The method for recycling photovoltaic modules according to claim 9 , wherein a part of the surface of the second transparent substrate is coated with a reflective white glaze layer or pasted with a reflective film. 11 .

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