Apparatus and method for separating decommissioned solar cells

Abstract

The application discloses a device and method for separating retired solar cells, and belongs to the technical field of retired solar cell recycling. The device comprises a pressure tank, an electric furnace and a motor. One side of the pressure tank is provided with a cover, and a gas release valve is arranged on the cover. A temperature sensor is arranged on the pressure tank body. The other side of the pressure tank is provided with a pressure gauge and a connecting rod. The connecting rod is connected with the motor. The motor is arranged in a device box. A motor rotating speed adjusting knob is arranged on the device box. The electric furnace is arranged below the pressure tank. An electric furnace power switch, an electric power adjusting knob and a temperature gauge are arranged on the electric furnace. The steps for separating the retired solar cells by using the device are as follows: after the solar cells are pretreated, the solar cells are put into the pressure tank, and the switch is turned on. The related parameters are adjusted by the knobs of the electric furnace and the device box, so that the solar cells are separated. The application has the advantages of being green, efficient, low in cost, free of harmful gas emission and the like.

Description

Technical Field

[0001] This invention relates to an apparatus and method for separating decommissioned solar cells, belonging to the field of decommissioned solar cell recycling technology. Background Technology

[0002] The demand for low-carbon emissions and the energy crisis have driven the rapid development of the global photovoltaic (PV) industry. In 2023, global new solar PV installations reached 345.5 GW, with a cumulative installed capacity of 1.42 TW. It is projected to reach 10 TW by 2030 and 30-80 TW by 2050. However, as large-scale global PV deployment continues, the challenge of disposing of a large number of PV modules at the end of their approximately 25-30 year lifespan is emerging. PV modules are far from being waste; they are a valuable urban resource.

[0003] Crystalline silicon solar cells are widely used due to their mature technology, with crystalline silicon modules accounting for over 95% of the market share. Ag and Si account for 47% and 11% of their economic value, respectively. Besides Ag and Si, crystalline silicon solar modules also contain Al, Cu, Sn, Pb, and glass, which account for approximately 65% ​​of the production cost of photovoltaic modules. In addition, small amounts of heavy metals, such as Sn and Pb, and organic matter, if not properly managed, can pose environmental hazards. Efforts have been made to develop efficient and clean methods for recycling retired photovoltaic modules.

[0004] With the diversification of photovoltaic (PV) module types and the continuous advancement of PV module manufacturing processes, the development prospects of the PV module application market will be even broader. The development of PV modules faces more diversified requirements. The market and related industries not only demand improved conversion efficiency of PV modules but also require continuous reduction of raw material and manufacturing costs and lower energy consumption. Second-generation retired PV modules are welcomed by the industry and market due to their advantages such as less material consumption, more mature manufacturing processes, lower energy consumption, lighter weight, higher photoelectric conversion efficiency, and lower degradation rate. Second-generation retired PV modules, with retired CIGS solar cells as a typical example, saw a production volume of 1.3GW of retired solar cells in 2015, 1.9GW in 2017, and are projected to reach 4.37GW by 2023. Simultaneously, the market share of retired solar cells is expected to increase from 16.7% in 2030 to 50% in 2040. Given their expected lifespan of 20-30 years, a large number of waste retired solar cells will be generated in the near future. In the next 5-10 years, a large number of retired solar cells will be scrapped, and this number will increase rapidly over time.

[0005] Therefore, recycling retired solar cells is of great significance. Currently, there are many recycling methods for retired solar cells, including pyrometallurgical recycling, wet recycling, combined pyrometallurgical and wet recycling, physical recycling, etc. However, there is little research on efficient and clean interlayer separation of retired solar cells. If the interlayers of retired solar cells can be separated first and then recycled, it will greatly reduce the difficulty of recycling, reduce the recycling time, improve the recycling efficiency, reduce the energy consumption of recycling, reduce the consumption of chemical reagents, and reduce the emission of harmful gases.

[0006] Therefore, how to carry out interlayer separation of decommissioned solar cells in a green, efficient, and low-cost manner has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] To address the shortcomings and deficiencies of existing decommissioned solar cell interlayer separation technologies, one objective of this invention is to provide a method for separating decommissioned solar cells, specifically including the following steps:

[0008] (1) Curve the decommissioned solar cells at a certain curvature, with a curvature range of 25m. -1 ~50m -1 Cut into battery cells.

[0009] (2) Place the cut battery cells into a container filled with deionized water for ultrasonic treatment.

[0010] (3) The battery cells processed in step (2) are placed in a pressure vessel, deionized water is added and heated. When the temperature and pressure reach a certain value, the pressure in the sealed container is released instantly to separate the battery cells and obtain the separated product.

[0011] (4) Collect the separated product obtained in step (3) and dry it to obtain the separated product.

[0012] Preferably, the decommissioned solar cells in step (1) include: decommissioned CIGS solar cells, whose structure from top to bottom consists of encapsulated PET, EVA film, cell layer, stainless steel backplate, EVA film, and encapsulated PET; the cutting size is 1×1cm to 16×16cm; and decommissioned crystalline silicon solar cells, whose structure from top to bottom consists of glass, EVA film, cell layer, and TPT backplate; the cutting size is 1×1cm to 4×4cm.

[0013] Preferably, the curvature range in step (1) is 30m. -1 ~50m -1 .

[0014] Preferably, the ultrasonic treatment time in step (2) is 10 to 120 min.

[0015] Preferably, in step (3), the amount of deionized water added per gram of battery cell is 1-20 ml; the pressure is controlled at 2-4 MPa and the temperature is controlled at 100-300℃.

[0016] Preferably, the drying conditions in step (4) are vacuum 50°C and drying for 40 min.

[0017] Another object of the present invention is to provide an apparatus for separating decommissioned solar cells, the apparatus comprising a pressure vessel and an electric furnace, the pressure vessel being placed above the electric furnace for convenient heating of the pressure vessel by the electric furnace, and a venting valve being installed on the pressure vessel to release the pressure inside the pressure vessel instantly.

[0018] Preferably, the electric furnace wall is equipped with an electric furnace power switch, an electric power adjustment knob, and a temperature gauge; the electric furnace power switch is used to control the opening and closing of the electric furnace, and the electric power adjustment knob is used to adjust the power of the electric furnace.

[0019] Preferably, a cover is connected to one side of the pressure tank, a vent valve is installed on the cover, a temperature sensor is installed on the side wall inside the pressure tank to monitor the temperature inside the pressure tank, and a pressure gauge is installed on the pressure tank to monitor the pressure inside the pressure tank.

[0020] Preferably, the pressure tank can be connected to the motor via a connecting rod. The motor is fixedly installed inside the device box, and the speed of the motor can be adjusted by adjusting the speed adjustment knob. The motor can rotate the pressure tank via the connecting rod to ensure that the pressure tank is heated evenly.

[0021] The principle of this invention:

[0022] (1) Curvature control is applied to retired solar cells to create gaps between layers by squeezing them together, so that deionized water can diffuse between the layers during the ultrasonic process.

[0023] (2) The treated decommissioned solar cells are placed in a pressure tank and deionized water is added. As the temperature of the pressure tank rises, the temperature of the deionized water continues to rise, accelerating its diffusion between the layers of the cell. As the temperature rises further, the deionized water in the gaps between the layers of the cell vaporizes. During this process, the deionized water changes from liquid to gas and expands in volume, which further increases the gaps between the layers and weakens the adhesion between the layers.

[0024] (3) During the process of the pressure tank temperature rise, due to the different thermal expansion properties between the layers of the retired battery, the encapsulated PET / glass, encapsulated EVA, battery cells and stainless steel substrate / TPT backplate undergo varying degrees of volume shrinkage or expansion, which further widens the gap between the layers and further weakens the adhesion between the layers.

[0025] (4) When the vent valve is opened and the pressure tank is opened, the pressure inside the pressure tank drops from a high pressure state to a normal pressure state. The water vapor between the layers of the battery cell also drops from a high pressure state to a normal pressure state. According to the ideal gas law PV=nRT, the amount of water vapor between the layers of the battery cell will not change, the temperature will not change much, and the sharp drop in pressure will cause the water vapor volume to expand instantaneously. Based on the combined principles (1)(2)(3)(4), the layers of the retired battery will separate.

[0026] The beneficial effects of this invention are:

[0027] (1) The present invention can orderly separate the layers of the decommissioned solar cell within 3 to 5 minutes, thereby achieving efficient interlayer separation of the decommissioned solar cell.

[0028] (2) While efficiently separating and decomposing solar cells, only deionized water is introduced as a medium, without any other chemical additives. No pollutants are generated in the whole process, thus achieving the goal of green and environmental protection.

[0029] (3) The present invention enables the effective enrichment of valuable metals in decommissioned solar cells. The enrichment of valuable metals in decommissioned solar cells after interlayer separation by this method is increased by more than 3.5 times.

[0030] (4) The present invention exposes the cell layers in the retired solar cells, which greatly facilitates the subsequent recycling of valuable metals and significantly improves the leaching rate of valuable metals. Attached Figure Description

[0031] Figure 1 This is a flowchart of a method for separating decommissioned solar cells.

[0032] Figure 2 This is a schematic diagram of a device for separating decommissioned solar cells.

[0033] In the diagram: 1. Cover; 2. Vent valve; 3. Temperature sensor; 4. Pressure tank; 5. Pressure gauge; 6. Connecting rod; 7. Device box; 8. Motor; 9. Speed ​​adjustment knob; 10. Thermometer; 11. Electric furnace; 12. Electric power adjustment knob; 13. Electric furnace power switch.

[0034] Figure 3 Images of the PET-cell, stainless steel backplate, encapsulated EVA, and encapsulated PET obtained from the separation of retired CIGS solar cells in Example 1.

[0035] Figure 4 Images of the PET-cell, stainless steel backplate, encapsulated EVA, and encapsulated PET obtained from the separation of retired CIGS solar cells in Example 2.

[0036] Figure 5 Images of the PET-cell, stainless steel backplate, encapsulated EVA, and encapsulated PET obtained from the separation of retired CIGS solar cells in Example 3.

[0037] Figure 6 Images of the glass, solar cell, encapsulated EVA, and TPT backplane obtained from the separation of decommissioned crystalline silicon solar cells in Example 4.

[0038] Figure 7 Images of the glass, solar cell, encapsulated EVA, and TPT backplane obtained from the separation of decommissioned crystalline silicon solar cells in Example 5. Detailed Implementation

[0039] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are merely simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0040] A device for separating decommissioned solar cells, such as Figure 2 As shown, the device mainly consists of three parts: a pressure tank 4, an electric furnace 11, and a motor 8. The electric furnace 11 has a power switch 13 and a power adjustment knob 12 on its wall. The power switch 13 controls the opening and closing of the electric furnace 11, and the power adjustment knob 12 adjusts the power of the furnace. The pressure tank 4 is placed above the electric furnace to heat it. A temperature sensor 3 is installed on the inner side wall of the pressure tank 4 to monitor the internal temperature. A cover 1 is installed on one side of the pressure tank 4, and a vent valve 2 is fixedly connected to the cover 1. A pressure gauge 5 and a thermometer 10 are installed on the other side of the pressure tank 4 to monitor the internal pressure and temperature. A connecting rod 6 is fixedly connected to the pressure tank 4, and the connecting rod 6 is connected to the motor 8. The motor 8 can drive the pressure tank 4 to rotate via the connecting rod 6. The motor speed adjustment knob 9 is located on the housing 7 where the motor 8 is installed and fixed.

[0041] Example 1

[0042] A method for separating decommissioned solar cells using the apparatus described in this invention comprises the following steps:

[0043] (1) Curl the decommissioned CIGS solar cells at a certain curvature, with a curvature of 50m. -1 The cells were cut into 2×2cm pieces and placed in a beaker containing deionized water for sonication for 30 minutes.

[0044] (2) Open the lid 1 of the pressure tank 4 and put the battery cells processed in step (2) into the pressure tank 4. Add 2ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the electric power adjustment knob 12 to make the electric furnace power 1000W, and let the electric furnace 11 start heating the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 100r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the temperature inside the pressure tank 4 reaches 225℃ and the pressure reaches 3MPa after the device has been running for 2 minutes and 40 seconds, press the vent valve 2 to release the gas instantly and obtain the product.

[0045] (3) The product collected in step (2) is vacuum dried at a temperature of 50°C for 40 minutes to obtain the product after interlayer separation of the decommissioned solar cell, such as... Figure 3 As shown, it includes: a PET-cell layer, a stainless steel backplate, EVA, and encapsulated PET. The separation of the stainless steel backplate increases the cell exposure rate to 99.8% and improves the enrichment of valuable metals by an average of about 3.5 times.

[0046] Example 2

[0047] A method for separating decommissioned solar cells using the apparatus described in this invention comprises the following steps:

[0048] (1) The decommissioned CIGS solar cells are rolled up at a certain curvature, with a curvature of 40m. -1 The cells were cut into 2×2cm pieces and placed in a beaker containing deionized water for sonication for 40 minutes.

[0049] (2) Open the lid 1 of the pressure tank 4 and put the battery cells processed in step (2) into the pressure tank 4. Add 3ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the electric power adjustment knob 12 to make the electric furnace power 1000W, and let the electric furnace 11 start heating the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 120r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the temperature inside the pressure tank 4 reaches 218℃ and the pressure reaches 3MPa after the device has been running for 3 minutes, press the vent valve 2 to release the gas instantly and obtain the product.

[0050] (3) The product collected in step (2) is vacuum dried at a temperature of 50°C for 40 minutes to obtain the product after interlayer separation of the decommissioned solar cell, such as Figure 4 As shown, it includes: a PET-cell layer, a stainless steel backplate, EVA, and encapsulated PET. The separation of the stainless steel backplate increases the cell exposure rate to 99.7% and improves the enrichment of valuable metals by an average of about 3.5 times.

[0051] Example 3

[0052] A method for separating decommissioned solar cells using the apparatus described in this invention comprises the following steps:

[0053] (1) Curl the decommissioned CIGS solar cells at a certain curvature, with a curvature of 30m. -1 The cells were cut into 2×2cm pieces and placed in a beaker containing deionized water for sonication for 60 minutes.

[0054] (2) Open the lid 1 of the pressure tank 4 and put the battery cells processed in step (2) into the pressure tank 4. Add 5ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the electric power adjustment knob 12 to make the electric furnace power 1000W, and let the electric furnace 11 start heating the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 150r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the temperature inside the pressure tank 4 reaches 235℃ and the pressure reaches 3MPa after the device has been running for 4 minutes, press the vent valve 2 to open the instantaneous differential pressure separator.

[0055] (3) The product collected in step (2) is vacuum dried at a temperature of 50°C for 40 minutes to obtain the product after interlayer separation of the decommissioned solar cell, such as Figure 5 As shown, it includes: PET-cell layer, stainless steel backplate, EVA, and encapsulated PET. The separation of the stainless steel backplate increases the cell exposure ratio to 99.1% and improves the enrichment of valuable metals by an average of about 3.4 times.

[0056] Example 4

[0057] A method for separating decommissioned solar cells using the apparatus described in this invention comprises the following steps:

[0058] (1) The decommissioned crystalline silicon solar cells are rolled up at a certain curvature, with a curvature of 50m. -1 The cells were cut into 2×2cm pieces and placed in a beaker containing deionized water for sonication for 40 minutes.

[0059] (2) Open the lid 1 of the pressure tank 4 and put the battery cells processed in step (2) into the pressure tank 4. Add 4ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the electric power adjustment knob 12 to make the electric furnace power 1000W, and let the electric furnace 11 start heating the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 120r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the temperature inside the pressure tank 4 reaches 261℃ and the pressure reaches 6MPa after the device has been running for 4 minutes, press the vent valve 2 to release the gas instantly and obtain the product.

[0060] (3) The product collected in step (2) is vacuum dried at a temperature of 50°C for 40 minutes to obtain the product after interlayer separation of the decommissioned solar cell, such as Figure 6 As shown, it includes: glass, EVA, battery cells, and TPT backplane.

[0061] Example 5

[0062] A method for separating decommissioned solar cells using the apparatus described in this invention comprises the following steps:

[0063] (1) The decommissioned crystalline silicon solar cells are rolled up at a certain curvature, with a curvature of 50m. -1 The battery cells were cut into 3×3cm pieces and placed in a beaker containing deionized water for sonication for 40 minutes.

[0064] (2) Open the lid 1 of the pressure tank 4 and put the battery cells processed in step (2) into the pressure tank 4. Add 5ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the electric power adjustment knob 12 to make the electric furnace power 1000W, and let the electric furnace 11 start heating the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 150r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the temperature inside the pressure tank 4 reaches 283℃ and the pressure reaches 7MPa after the device has been running for 5 minutes, press the vent valve 2 to release the gas instantly and obtain the product.

[0065] (3) The product collected in step (2) is vacuum dried at a temperature of 50°C for 40 minutes to obtain the product after interlayer separation of the decommissioned solar cell, such as Figure 7 As shown, it includes: glass, EVA, battery cells, and TPT backsheet.

[0066] The above are merely some of the embodiments of this application and are not intended to limit the application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments shall still fall within the scope of protection of the technical solution of this application.

Claims

1. A method for separating decommissioned solar cells, characterized in that: Specifically, the following steps are included: (1) The retired solar cells are classified according to their curvature range of 25m. -1 ~50m -1 The curvature is curled and cut into battery sheets; (2) The cut battery cells are placed in a container of deionized water for ultrasonic treatment. During the ultrasonic process, the deionized water diffuses between the layers. (3) Place the battery cells processed in step (2) into a pressure vessel, add 1-20 ml of deionized water per gram of battery cell, control the pressure to 2-4 MPa, control the temperature to 100-300℃, release the pressure in the sealed container instantly, and at the moment the pressure vessel is opened, the pressure vessel inside drops from a high pressure state to a normal pressure state, and the water vapor between the layers of the battery cells also drops from a high pressure state to a normal pressure state. The pressure reduction will cause the water vapor volume to expand instantaneously, causing the layers of the retired battery to separate, and the product is obtained. (4) Collect the product obtained in step (3) and dry it to obtain the separated product.

2. The method for separating decommissioned solar cells according to claim 1, characterized in that: The decommissioned solar cells mentioned in step (1) include: CIGS solar cells, whose structure from top to bottom consists of encapsulated PET, EVA film, cell layer, stainless steel backplate, EVA film, and encapsulated PET; the cutting size is 1×1cm to 16×16cm; crystalline silicon solar cells, whose structure from top to bottom consists of encapsulated glass, EVA film, cell layer, and TPT backplate; the cutting size is 1×1cm to 4×4cm; and other decommissioned solar cells with interlayer structures.

3. The method for separating decommissioned solar cells according to claim 1, characterized in that: The ultrasonic treatment time in step (2) is 10 to 120 minutes.

4. The method for separating decommissioned solar cells according to claim 1, characterized in that: In step (4), the drying conditions are vacuum 50°C and drying for 40 min.

5. The method for separating decommissioned solar cells according to claim 1, characterized in that: It also includes an electric furnace (11), the pressure tank (4) is placed on the electric furnace (11), and a venting valve (2) is installed on the pressure tank (4).

6. The method for separating decommissioned solar cells according to claim 5, characterized in that: The electric furnace (11) is equipped with an electric furnace power switch (13) and an electric power adjustment knob (12) on its wall.

7. The method for separating decommissioned solar cells according to claim 5, characterized in that: A cover (1) is connected to one side of the pressure tank (4), a vent valve (2) is installed on the cover (1), a temperature sensor (3) is installed on the side wall inside the pressure tank (4), and a pressure gauge (5) and a temperature gauge (10) are also installed on the pressure tank (4).

8. The method for separating decommissioned solar cells according to claim 5, characterized in that: The pressure tank (4) can be connected to the motor (8) via the connecting rod (6). The motor is fixedly installed in the device box (7), and the speed adjustment knob (9) of the motor (8) is placed on the device box (7).

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