A method for recycling a crystalline silicon solar cell module

Abstract

The application relates to a recycling method of a crystalline silicon solar cell assembly, which comprises the following steps: S1, removing the assembly frame and the junction box; S2, cutting a first EVA layer by using a first tool cutter to obtain material A and a first material, wherein the material A comprises the back plate attached with a part of the first EVA layer; S3, cutting the silicon wafer in the first material along the tinned copper strip by using a second tool cutter to obtain material B and a second material, wherein the material B comprises the tinned copper strip attached with another part of the first EVA layer and a part of the silicon wafer covered by the tinned copper strip; S4, cutting the second EVA layer by using a third tool cutter to obtain material C and a third material, wherein the material C comprises another part of the silicon wafer and a part of the second EVA layer, and the third material comprises another part of the second EVA layer and the front plate glass; and S5, respectively performing heating treatment and wet metallurgical treatment on the material B and the material C.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a recycling method of a crystalline silicon solar cell module. BACKGROUND

[0002] The service life of a crystalline silicon solar module is generally 20-25 years, and the number of retired photovoltaic modules will gradually increase in the future. If these retired modules cannot be reasonably and effectively recycled, it will cause waste of resources and materials and serious environmental pollution.

[0003] At present, the industrialization technology for recycling crystalline silicon modules is not mature, especially in the aspect of module disassembly, which faces problems such as high cost and serious environmental pollution. For example, the inorganic solvent / organic solvent method takes a long time to disassemble the module, requires a large amount of solvent, and the waste liquid is difficult to treat; the thermal decomposition method consumes a lot of energy and produces harmful gases such as hydrofluoric acid; the module is broken as a whole and sieved or sorted, and the purity of each material is not high, making it difficult to recycle high-purity materials.

[0004] In addition, with the continuous development of photovoltaic technology, the size of the cell chip becomes larger, the thickness becomes thinner, new processes and high-integration equipment appear, and it is difficult to directly reuse the complete silicon wafer on the new production line at a high cost. Therefore, in the module recycling, the integrity of the silicon wafer recycling is not so important; it is more important to efficiently separate the module, save energy and reduce emissions, reduce pollution, obtain high-purity recycled materials, and reuse them.

[0005] For example, CN110491969A discloses a recycling method of a crystalline silicon photovoltaic module. After removing the external junction box and aluminum frame of the crystalline silicon photovoltaic module to be recycled, the EVA layers are softened by heating; then a metal cutter / wire is used to cut along different EVA layers to separate the glass layer, cell chip layer or back plate layer from other parts, and each part can be recycled separately.

[0006] However, the recycling efficiency of silicon and metal in the existing recycling method still needs to be further improved. SUMMARY

[0007] The purpose of the present application is to provide a recycling method of a crystalline silicon solar cell module, which uses a pure physical method to efficiently disassemble the solar cell module and obtain different materials that are easier to recycle and process, thereby improving the recycling efficiency.

[0008] In order to achieve the above purpose, the present application provides a recycling method of a crystalline silicon solar cell module, which comprises a junction box, a back plate, a first EVA layer, a tinned copper ribbon, a silicon wafer, a second EVA layer, a front plate glass and a module frame from bottom to top, and the recycling method comprises:

[0009] S1, removing the module frame and the junction box;

[0010] S2, cutting the first EVA layer by using a first tool cutter to obtain material A and a first material, the material A comprising the back plate with a part of the first EVA layer attached thereto;

[0011] S3, cutting the silicon wafer in the first material by using a second tool cutter along the tin-coated copper strip to obtain material B and a second material, the material B comprising the tin-coated copper strip with another part of the first EVA layer attached thereto and a part of the silicon wafer covered by the tin-coated copper strip;

[0012] S4, cutting the second EVA layer by using a third tool cutter to obtain material C and a third material, the material C comprising another part of the silicon wafer and a part of the second EVA layer, and the third material comprising another part of the second EVA layer and the front plate glass;

[0013] S5, performing first heating treatment and first hydrometallurgical treatment on the material B, and performing second heating treatment and second hydrometallurgical treatment on the material C.

[0014] Optionally, in step S2, the thickness of the first EVA layer is 0.5 mm, and the thickness of the part of the first EVA layer is 0.1-0.4 mm.

[0015] Optionally, in step S4, the thickness of the second EVA layer is 0.5 mm, and the thickness of the part of the second EVA layer is 0.1-0.4 mm.

[0016] Optionally, the first tool cutter and the third tool cutter are each independently a disc cutter, and the second tool cutter is a cylindrical cutter.

[0017] Optionally, the temperature of the first heating treatment is 300-800℃, and the time is 5-90 min.

[0018] Optionally, the temperature of the first heating treatment is preferably 500-600℃, and the time is preferably 10-60 min.

[0019] Optionally, the temperature of the second heating treatment is 300-800℃, and the time is 5-90 min.

[0020] Optionally, the temperature of the second heating treatment is preferably 500-600℃, and the time is preferably 10-60 min.

[0021] Optionally, the recycling method further comprises: performing pyrolysis treatment on the third material to obtain the front plate glass.

[0022] Optionally, the temperature of the pyrolysis treatment is 500-600℃, and the time is 10-60 min.

[0023] Through the technical scheme, high-purity silicon, copper, silver, back plate, front plate glass and other materials can be obtained by the milling cutter process, heat treatment and step-by-step hydrometallurgical purification treatment, and the enrichment degree of each material is high. Through the heat treatment, the material B is in a granular form and is high in copper enrichment. Compared with the existing crushing technology, the additional grinding and crushing process is not needed, the high-purity copper is more easily obtained by the hydrometallurgical treatment, the process time and cost are greatly saved, and the recovery efficiency is improved. Compared with the existing crushing technology, the material C does not contain glass and back plate, and the mass ratio of glass and back plate in the assembly is more than 70%, so the mass ratio of silver in the material is more than 70% higher than that of the prior art by the recycling method of the present application, so it is also easier to obtain high-purity silver by the silver recycling process, and the use of solvent is greatly reduced, and the silver recycling cost is greatly reduced. The recycling method of the present application is simple, easy to realize, energy-saving and environment-friendly, the purity of the separated materials is high, and efficient recycling of resources is realized.

[0024] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the present application, but do not constitute a limitation on the present application. In the drawings:

[0026] Figure 1 is a structural schematic diagram of a crystalline silicon solar cell module of the present application;

[0027] Figure 2 is a schematic diagram after removing the junction box and the module frame of the present application;

[0028] Figure 3 is a structural schematic diagram after removing the back plate and part of the EVA by using a disc milling cutter for the first time in the present application;

[0029] Figure 4 is a schematic diagram of removing the tinned copper strip by using a cylindrical milling cutter for the second time in the present application;

[0030] Figure 5 is a structural schematic diagram after removing the silicon wafer and part of the EVA by using a disc milling cutter for the third time in the present application. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0032] The application provides a recycling method of a crystalline silicon solar cell assembly, the crystalline silicon solar cell assembly comprises, from bottom to top, a junction box, a back plate, a first EVA layer, a tinned copper strip, a silicon wafer, a second EVA layer, a front plate glass and an assembly frame, and the recycling method comprises the following steps:

[0033] S1, removing the assembly frame and the junction box;

[0034] S2, cutting the first EVA layer by using a first tool knife to obtain material A and a first material, wherein the material A comprises the back plate with a part of the first EVA layer attached thereto;

[0035] S3, cutting the silicon wafer in the first material along the tinned copper strip by using a second tool knife to obtain material B and a second material, wherein the material B comprises the tinned copper strip with another part of the first EVA layer attached thereto and a part of the silicon wafer covered by the tinned copper strip;

[0036] S4, cutting the second EVA layer by using a third tool knife to obtain material C and a third material, wherein the material C comprises another part of the silicon wafer and a part of the second EVA layer, and the third material comprises another part of the second EVA layer and the front plate glass;

[0037] S5, performing first heating treatment and first hydrometallurgical treatment on the material B, and performing second heating treatment and second hydrometallurgical treatment on the material C.

[0038] In the present application, the first tool knife can completely collect the back plate, and the back plate can be effectively collected by blowing or vacuum adsorption. Since the back plate contains fluorine, the present application can avoid fluorine pollution caused by other high-temperature technologies. The second tool knife can obtain the tinned copper strip. In order to remove all the tinned copper strip, a small amount of silicon wafer will be broken during removal, and another part of the first EVA layer and a small amount of silicon wafer will be adhered to the tinned copper strip. Compared with other processes that break the entire assembly, the present application is easier and more complete to separate, can better enrich the copper material, and the subsequent copper recovery process is simpler and the recovery cost is lower. The third tool knife can separate the silicon wafer (including the silver grid line) and the front plate glass. In order to reduce the fragmentation of the silicon wafer and make the separation of silver easier, a part of the second EVA layer will be retained on the silicon wafer, which can better enrich the silicon wafer and the silver grid line material. The material B and the material C are classified and subjected to heat treatment to remove EVA, and at the same time, the material B and the material C become granular, and further subjected to hydrometallurgy treatment, so as to obtain silicon particles, high-purity copper, high-purity silver and other metals. Compared with the traditional high-temperature treatment method of the entire assembly, the present application can remove EVA more quickly and efficiently, and is more energy-saving. Compared with the existing breaking technology, the present application does not need additional grinding and crushing process, greatly saves process time and cost, and improves recovery efficiency; and the separated material has high purity, realizing efficient recycling of resources.

[0039] According to the present application, optionally, in step S2, the thickness of the first EVA layer can be 0.5 mm; the thickness of a part of the first EVA layer can be 0.1-0.4 mm.

[0040] According to the present application, optionally, in step S4, the thickness of the second EVA layer can be 0.5 mm; the thickness of a part of the second EVA layer can be 0.1-0.4 mm.

[0041] According to the present application, optionally, the first tool knife and the third tool knife are each independently a disc cutter; and the second tool knife is a cylindrical cutter. The use of a milling cutter process can realize the separation of the front plate glass, EVA, tinned copper strip, silicon wafer and fluorine-containing back plate of the solar module. The milling machine technology industry is quite mature, the machining precision can reach 0.01-0.02 mm, and the surface roughness can reach 3-20 μm.

[0042] According to the present application, optionally, the temperature of the first heat treatment can be 300-800℃, preferably 500-600℃, and the time can be 5-90 min, preferably 10-60 min. In the above embodiment, the EVA is completely vaporized by heat treatment, and at the same time, the material B becomes granular, obtaining the tinned copper strip and a small amount of broken silicon particle material, and the silicon particles can be obtained by subsequent screening and sorting methods.

[0043] According to the present invention, optionally, the temperature of the second heat treatment is 300-800℃, preferably 500-600℃, and the time is 5-90 min, preferably 10-60 min. In the above embodiments, the EVA is completely vaporized by heat treatment, and the material C becomes granular, yielding silicon particles, silver grid lines, and a small amount of metals such as aluminum. The silicon particles obtained by the present invention have a higher purity than those obtained by traditional whole-component crushing processes, and the silicon particles are easier to purify into high-purity silicon, such as 5N, 6N, 7N, 8N, and 9N grades. The methods for purifying high-purity silicon are well known to those skilled in the art and will not be described in detail here.

[0044] According to the present invention, optionally, the first and second hydrometallurgical processes are known to those skilled in the art and will not be described in detail here. High-purity copper, silver, and other metals can be obtained through hydrometallurgical processes.

[0045] According to the present invention, optionally, the recycling method further includes: pyrolyzing the third material to obtain the front glass.

[0046] According to the present invention, optionally, the pyrolysis treatment temperature is 500-600°C and the time is 10-60 minutes. In the above embodiment, the pyrolysis treatment can remove another portion of the second EVA layer, resulting in a clean and complete front panel glass.

[0047] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0048] Example

[0049] See Figure 2 The crystalline silicon solar cell module of the present invention, after removing the junction box and module frame, includes, from bottom to top, the following: back sheet (taking TPT as an example, 0.35mm thick), first EVA layer (0.5mm thick), tin-plated copper strip (0.08mm-0.25mm thick), crystalline silicon cell (0.19mm thick), second EVA layer (0.5mm thick), and front glass (0.5mm thick).

[0050] This embodiment recycles crystalline silicon solar cell modules through the following steps:

[0051] S1. Remove the component frame and the junction box;

[0052] S2, such as Figure 3 As shown, the first EVA layer is cut with a disc milling cutter to obtain material A and a first material. Material A includes a back plate to which a portion of the first EVA layer is attached; the thickness of the portion of the first EVA layer is 0.3 mm.

[0053] S3, such as Figure 4 As shown, a cylindrical milling cutter is used to cut the silicon wafer in the first material along the tin-plated copper strip to obtain material B and a second material. Material B includes the tin-plated copper strip with another portion of the first EVA layer attached and a portion of the silicon wafer covered by the tin-plated copper strip. The copper content in material B is 30% to 50% by mass, accounting for 90% to 100% of the total copper content in the crystalline silicon solar cell module. The silver content in material B is 0.2% to 0.8% by mass, accounting for 25% to 35% of the total silver content in the crystalline silicon solar cell module.

[0054] S4, such as Figure 5 As shown, the second EVA layer is cut using a milling cutter to obtain material C and a third material. Material C includes another portion of the silicon wafer and a portion of the second EVA layer, the thickness of which is 0.3 mm. The third material includes another portion of the second EVA layer and the front glass. The third material is pyrolyzed at 550°C for 40 minutes to remove the other portion of the second EVA layer, obtaining the front glass. The silicon content in material C is 30%–60%, accounting for 80%–90% of the total silicon in the crystalline silicon solar cell module. The silver content in material C is 0.5%–0.8%, accounting for 65%–75% of the total silver in the crystalline silicon solar cell module.

[0055] S5. The material B is subjected to a first heat treatment at 550°C for 40 minutes, followed by a first hydrometallurgical treatment to obtain metallic copper and silver. The material C is subjected to a second heat treatment at 550°C for 40 minutes to obtain silicon particles, silver grid lines, and a small amount of aluminum and other metals, followed by a second hydrometallurgical treatment to obtain silver, aluminum, and other metals.

[0056] Comparative Example

[0057] This comparative example demonstrates the recycling of crystalline silicon solar cell modules through the following steps:

[0058] S1. Remove the frame and junction box of the crystalline silicon solar cell module;

[0059] S2. Use a metal tool to peel off the first EVA layer to obtain a backplate and component A with the first EVA layer attached.

[0060] S3. Use a metal cutting tool to peel off the tin-plated copper strip in the component A to obtain the tin-plated copper strip and component B; the copper content in the tin-plated copper strip is 5% to 15%, accounting for 60% to 70% of the total copper in the crystalline silicon solar cell module;

[0061] S4, using a metal cutter to strip the second EVA layer in the component B to obtain a silicon wafer and a front plate glass with the second EVA layer attached; the silicon mass content in the silicon wafer is 10% to 20%, the proportion of the total silicon in the crystalline silicon solar cell component is 60% to 75%, the silver mass content is 0.2% to 0.4%, and the proportion of the total silver in the crystalline silicon solar cell component is 45% to 60%.

[0062] S5, the tin-plated copper strip is subjected to a first heating treatment at 550 DEG C for 40 min, and then subjected to a first hydrometallurgical treatment to obtain a metal copper; the silicon wafer is subjected to a second heating treatment at 550 DEG C for 40 min to obtain silicon particles, silver-containing grid lines and a small amount of aluminum and other metals, and then subjected to a second hydrometallurgical treatment to obtain silver, aluminum and other metals.

[0063] According to the above examples and comparative examples, when stripping by the recovery method of the comparative example, the EVA layer is completely removed, and there is no EVA attached to the tin-plated copper strip, which cannot better enrich the copper material; at the same time, there is also no EVA attached to the silicon wafer, which is easy to cause the fragmentation and sputtering of the silicon wafer, making the separation of silver more difficult, and cannot better enrich the silicon wafer and silver-containing grid line material, which is not conducive to the purification of copper, silver and other metals by subsequent hydrometallurgical treatment. The recovery method of the present application mainly uses a milling cutter process to efficiently and energy-efficiently disassemble the crystalline silicon solar cell component by a pure physical method, completely realizes the separation of the front plate glass, the tin-plated copper strip, the silicon wafer and the back plate of the crystalline silicon solar cell component, and each material has high enrichment and high purity, which is more conducive to the purification of metals and realizes efficient recycling of resources.

[0064] The preferred embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0065] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0066] In addition, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A method for recycling a crystalline silicon solar cell module, characterized by, The crystalline silicon solar cell assembly comprises, from bottom to top, a junction box, a back plate, a first EVA layer, a tin-plated copper strip, a silicon wafer, a second EVA layer, a front plate glass and an assembly frame, and the recycling method comprises the following steps: S1, removing the assembly frame and the junction box; S2, cutting the first EVA layer by using a first tool cutter to obtain material A and a first material, the material A comprising the back plate with a part of the first EVA layer adhered thereto; the first tool cutter being a disc cutter; S3, cutting the silicon wafer in the first material along the tin-plated copper strip by using a second tool cutter to obtain material B and a second material, the material B comprising the tin-plated copper strip with another part of the first EVA layer adhered thereto and a part of the silicon wafer covered by the tin-plated copper strip; the copper mass content in the material B being 30% to 50%, accounting for 90% to 100% of the total amount of copper in the crystalline silicon solar cell assembly; the silver mass content in the material B being 0.2% to 0.8%, accounting for 25% to 35% of the total amount of silver in the crystalline silicon solar cell assembly; the second tool cutter being a cylindrical cutter; S4, cutting the second EVA layer by using a third tool cutter to obtain material C and a third material, the material C comprising another part of the silicon wafer and a part of the second EVA layer, and the third material comprising another part of the second EVA layer and the front plate glass; the silicon mass content in the material C being 30% to 60%, accounting for 80% to 90% of the total amount of silicon in the crystalline silicon solar cell assembly; the silver mass content in the material C being 0.5% to 0.8%, accounting for 65% to 75% of the total amount of silver in the crystalline silicon solar cell assembly; the third tool cutter being a disc cutter; S5, performing first heating treatment and first hydrometallurgical treatment on the material B, and performing second heating treatment and second hydrometallurgical treatment on the material C.

2. The recycling method of claim 1, wherein, In step S2, the thickness of the first EVA layer is 0.5 mm; the thickness of a part of the first EVA layer is 0.1-0.4 mm.

3. The recycling method according to claim 1 or 2, wherein, In step S4, the thickness of the second EVA layer is 0.5 mm; the thickness of a part of the second EVA layer is 0.1-0.4 mm.

4. The recycling method of claim 1, wherein, The temperature of the first heating treatment is 300-800℃, and the time is 5-90 min.

5. The recycling method of claim 4, wherein, The temperature of the first heating treatment is 500-600℃, and the time is 10-60 min.

6. The recycling method of claim 1, wherein, The temperature of the second heating treatment is 300-800℃, and the time is 5-90 min.

7. The recycling method of claim 6, wherein, The temperature of the second heating treatment is 500-600℃, and the time is 10-60 min.

8. The recycling method of claim 1, wherein, The recycling method further comprises: performing pyrolysis treatment on the third material to obtain the front plate glass.

9. The recycling method of claim 8, wherein, The temperature of the pyrolysis treatment is 500-600℃, and the time is 10-60 min.

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