Processing method for perovskite solar cell modules

Abstract

This invention provides a method for processing perovskite solar cell modules that allows for the removal or recovery of lead from the cleaning solvent of the perovskite solar cell modules using a simple method. [Solution] According to the present invention, a method for processing a perovskite solar cell module is provided, comprising a dissolution step, a deposition step, and a solid-liquid separation step, wherein in the dissolution step, the perovskite solar cell module is immersed in a cleaning solvent and ultrasonic waves are applied to peel off the plurality of functional layers from the transparent substrate and dissolve the perovskite photoelectric conversion layer in the cleaning solvent; in the deposition step, the lead dissolved in the cleaning solvent is precipitated as a sparingly soluble lead compound; and in the solid-liquid separation step, the lead compound and the cleaning solvent are separated.

Description

Technical Field

[0001] The present invention relates to a method for treating a perovskite solar cell module that can be a waste target such as used or defective products in manufacturing.

Background Art

[0002] Patent Document 1 discloses a technique for removing each functional layer of a perovskite solar cell module by immersing a used perovskite solar cell module in a predetermined cleaning solvent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since a perovskite solar cell module usually contains lead, the cleaning solvent in which each functional layer of the perovskite solar cell module is dissolved will contain lead. Assuming that the usage amount of perovskite solar cell modules will increase in the future, it can be said that it is preferable that the cleaning solvent for perovskite solar cell modules meets the drainage standards. For this purpose, a technique for removing or recovering lead from the cleaning solvent of perovskite solar cell modules by a simple method is desired.

[0005] The present invention has been made in view of such circumstances, and provides a method for treating a perovskite solar cell module capable of removing or recovering lead from the cleaning solvent of a perovskite solar cell module by a simple method.

Means for Solving the Problems

[0006] The present invention provides the following: [1] A method for processing a perovskite solar cell module, comprising a dissolution step, a deposition step, and a solid-liquid separation step, wherein the perovskite solar cell module comprises a transparent substrate and a plurality of functional layers, the plurality of functional layers comprising a perovskite photoelectric conversion layer, the dissolution step involves immersing the perovskite solar cell module in a cleaning solvent and applying ultrasound to peel the plurality of functional layers from the transparent substrate and dissolve the perovskite photoelectric conversion layer in the cleaning solvent, the deposition step involves precipitating the lead dissolved in the cleaning solvent as a sparingly soluble lead compound, and the solid-liquid separation step involves separating the lead compound from the cleaning solvent. A method for processing a perovskite solar cell module as described in [2][1], wherein the cleaning solvent is a dilute sulfuric acid aqueous solution and the sparingly soluble lead compound is lead sulfate. A method for processing a perovskite solar cell module according to [3] [1] or 2, wherein in the dissolution step, the washing solvent is heated to 40 to 80°C. A method for processing a perovskite solar cell module according to any one of [4][1] to [3], wherein in the deposition step, the washing solvent is cooled to 10°C or below. A method for processing a perovskite solar cell module according to any one of [5][1] to [4], further comprising an adsorption step, wherein in the adsorption step, lead remaining in the washing solvent after the solid-liquid separation step is adsorbed by a lead removal filter. A method for processing a perovskite solar cell module according to any one of [6][1] to [5], wherein the lead content of the washing solvent after the solid-liquid separation step or the lead content of the washing solvent after the adsorption step is 0.05 mg / L or less. [Effects of the Invention]

[0007] The present invention provides a method for processing perovskite solar cell modules that allows for the separation of lead from the washing solvent in which the photoelectric conversion layer has been dissolved, through a simple method consisting of a dissolution step, a deposition step, and a solid-liquid separation step. This enables the washing solvent to be discharged in a legal manner that meets wastewater standards, and also allows for handling cases where the amount of washing solvent used increases. Furthermore, if necessary, useful resources can be recovered and recycled from the washing solvent from which the lead has been removed. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows a processing method for a perovskite solar cell module 1 according to one embodiment. [Figure 2] Figure 2A is a perspective view showing the schematic configuration of the perovskite solar cell module 1, and Figure 2B is a diagram showing the schematic configuration of multiple functional layers 3. [Figure 3] Figure 3A shows a schematic of the dissolution step (S1), Figure 3B shows the state of the perovskite solar cell module 1 after the dissolution step (S1), and Figure 3C shows an example of the washing solvent 4 being stirred with a stirrer 6 during the deposition step (S2). [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an independent invention.

[0010] <Overview of processing methods for perovskite solar cell modules> As shown in Figure 1, the processing method for the perovskite solar cell module 1 of this embodiment includes a dissolution step (S1), a deposition step (S2), and a solid-liquid separation step (S3). In this embodiment, the target of processing is a used perovskite solar cell module 1. However, other perovskite solar cell modules that are to be discarded, such as those that have defects in the manufacturing process, may also be subject to processing according to the present invention.

[0011] As shown in Figure 2A, the perovskite solar cell module 1 comprises a transparent substrate 2 and a plurality of functional layers 3. The transparent substrate 2 is, for example, a glass substrate. However, the present invention can also be suitably applied even if the transparent substrate 2 is a resin film.

[0012] Multiple functional layers 3 are formed on a transparent substrate 2. As shown in Figure 2B, the multiple functional layers 3 include a transparent electrode layer 31, an electron transport layer 32, a perovskite photoelectric conversion layer 33, a hole transport layer 34, a back electrode layer 35, a sealing layer 36, and a backsheet layer 37. The configuration of each layer can be a known configuration, so a description is omitted. The present invention can also be suitably applied to the processing of a perovskite solar cell module 1 in which the arrangement order of the multiple functional layers 3 differs (e.g., a configuration in which a glass substrate, transparent electrode layer, hole block layer, electron transport layer, perovskite photoelectric conversion layer, hole transport layer, and back electrode (Au) are stacked).

[0013] In the dissolution step (S1), as shown in Figure 3A, the perovskite solar cell module 1 is immersed in a cleaning solvent 4 and ultrasonic waves are applied to peel off multiple functional layers 3 from the transparent substrate 2 and dissolve the perovskite photoelectric conversion layer 33 in the cleaning solvent 4. In this embodiment, an ultrasonic transducer 5 is provided on the bottom surface of a container 40 containing the cleaning solvent 4, and ultrasonic waves are applied to the perovskite solar cell module 1 by vibrating this ultrasonic transducer 5.

[0014] After a predetermined processing time has elapsed, as shown in Figure 3B, multiple functional layers 3 are peeled off from the transparent substrate 2. Of the multiple functional layers 3, at least the perovskite photoelectric conversion layer 33 dissolves in the cleaning solvent 4. In addition, of the transparent electrode layer 31, electron transport layer 32, hole transport layer 34, back electrode layer 35, sealing layer 36, and backsheet layer 37 peeled off from the transparent substrate 2, those that do not dissolve in the cleaning solvent 4 can be recovered from the cleaning solvent 4 as solids, as appropriate. Furthermore, the transparent substrate 2 can also be removed from the cleaning solvent 4 and recovered as appropriate.

[0015] In the dissolution step (S1), even if the washing solvent 4 is water, it is possible to remove all of the multiple functional layers 3 from the transparent substrate 2 by applying ultrasound. In this case, the dissolution step (S1) proceeds with water + ultrasound, and then the precipitation step (S2) is carried out by adding sulfuric acid or the like. However, it is possible to accelerate the reaction by adding an acid (sulfuric acid, hydrochloric acid, nitric acid, acetic acid, etc.) to water from the beginning as the washing solvent 4, and in this case, the dissolution step (S1) and the precipitation step (S2) can be carried out simultaneously.

[0016] In the precipitation step (S2), lead dissolved in the washing solvent 4 is precipitated as a sparingly soluble lead compound. When sulfuric acid is used as the washing solvent 4, lead sulfate (PbSO4) precipitates; when hydrochloric acid is used, lead chloride (PbCl2) precipitates; when nitric acid is used, lead nitrate (Pb(NO3)2) precipitates; when acetic acid is used, lead acetate (Pb(CH3COO)2) precipitates; and when phosphoric acid is used, lead phosphate (Pb3(PO4)2) precipitates. Since it is preferable that the solubility of the lead compound in the washing solvent 4 is low, sulfuric acid, phosphoric acid, and hydrochloric acid are preferred as the washing solvent 4, with sulfuric acid being particularly preferred.

[0017] The total processing time of the dissolution step (S1) and the precipitation step (S2) is about 10 to 60 minutes. The suitable temperature range of the washing solvent 4 is generally in the range of 20 to 100 °C, and 40 to 80 °C is preferred. The heating of the washing solvent 4 in the dissolution step (S1) can be carried out, for example, by a heating device such as a jacket heater disposed near the peripheral surface of the container 40.

[0018] In the solid-liquid separation step (S3), the lead compound and the washing solvent 4 are separated. A typical example of a method for separating the lead compound and the washing solvent 4 is filtration, but it is not limited thereto, and other methods such as centrifugation can also be used.

[0019] In order to increase the lead compound removal efficiency in the solid-liquid separation step (S3), if necessary, in the precipitation step (S2), it is preferable that the washing solvent 4 is cooled to 10 °C or lower. A heat exchanger such as a chiller can be used for cooling the washing solvent 4. In this case, for example, as shown in FIG. 3C, while cooling the washing solvent 4, by continuing the stirring by the stirrer 6, substances to be separated such as lead sulfate precipitate uniformly, and the lead recovery efficiency can reach a level "close to the theoretical value of the lead recovery efficiency".

[0020] In this embodiment, a dilute sulfuric acid aqueous solution having a concentration of about 0.1 to 0.3 mol / L (more preferably 0.2 to 0.3 mol / L) is preferably used as the washing solvent 4. Therefore, lead sulfate as a poorly soluble lead compound can be preferably recovered by filtration.

[0021] After the solid-liquid separation step (S3), an adsorption step (S4) may be further included as needed. In the adsorption step (S4), the lead remaining in the washing solvent 4 after the solid-liquid separation step (S3) is adsorbed by the lead removal filter. The lead removal filter can be any filter that has the function of adsorbing lead ions, and suitable examples include ion exchange resin filters, activated carbon filters, and silicate-based adsorption filters. Since these filters can be used as heavy metal removal filters, even if harmful metals other than lead (cadmium, zinc, etc.) are present, their concentrations can be reduced to less than 5 mg / L. Known methods can be applied to pass the liquid through the filter. When passing the liquid through the filter, natural flow at atmospheric pressure is acceptable, or pressurization or depressurization may be applied to shorten the processing time.

[0022] With the processing method for the perovskite solar cell module 1 described above, it is possible to reduce the lead content of the washing solvent 4 after the solid-liquid separation step (S3) or after the adsorption step (S4) to 0.05 mg / L or less. If the lead content of the washing solvent 4 is sufficiently low, it becomes possible to drain the washing solvent 4, thus making it possible to handle situations where a large amount of washing solvent 4 is generated.

[0023] The precipitate, mainly composed of lead compounds such as lead sulfate, recovered by the processing method of the perovskite solar cell module 1, can also be reprocessed into reusable lead oxide through an incineration process. For example, by incinerating the recovered lead compounds and converting them to lead oxide (PbO), they can be used as a reusable resource in the manufacture of batteries, electronic components, chemical products, etc. In this case, the amount of resources that can be effectively recycled increases, making it possible to reduce the amount of waste generated from used perovskite solar cell modules 1.

[0024] <Other Embodiments> In the above embodiment, an example was shown in which the perovskite solar cell module 1 is not crushed, taking into consideration the convenience of recycling the transparent substrate 2. However, the perovskite solar cell module 1 may be crushed before processing. [Examples]

[0025] Experiments were conducted to measure the residual lead concentration in the cleaning solvent 4 after cleaning a perovskite solar cell module 1 under various conditions. The perovskite solar cell module 1 used in the following experiments consisted of a 70mm x 70mm transparent substrate 2 (glass substrate) with a functional layer 3 containing a 180nm perovskite photoelectric conversion layer 33 formed on it. The perovskite photoelectric conversion layer 33 is CH3NH3PbI3 (methylammonium lead iodide), and its density is 4g / cm³. 3 Therefore, since the weight ratio of lead to the entire perovskite photoelectric conversion layer 33 is 59.5%, it was assumed that each perovskite solar cell module 1 used in each experiment contained a calculated amount of 2.099 mg of lead.

[0026] The perovskite solar cell module 1 was placed in container 40 (a beaker was used in the experiment) without being crushed, and 100 mg of washing solvent 4 was added. Washing solvent 4 is a 0.2 mol / L dilute sulfuric acid aqueous solution. The experimental results obtained when the processing time (corresponding to the total time of the dissolution step (S1) and the precipitation step (S2)) was varied to 10, 20, 30, and 60 minutes, and the temperature of washing solvent 4 was varied to 20, 40, 60, 80, and 90°C are shown in Table 1. During the experiment, stirring was performed at a stirring speed of 200 rpm. [Table 1]

[0027] The lead concentration in the solution was calculated from the value obtained by sampling the washing solvent 4 after removing sparingly soluble lead compounds (precipitate) by filtration with filter paper, and measuring it by ICP mass spectrometry (using an Agilient Technologies 7900 ICP-MS). As shown in Table 1, in Experimental Example 8 (processing time 60 minutes, processing temperature 40°C), Experimental Example 12 (processing time 60 minutes, processing temperature 60°C), Experimental Example 15 (processing time 30 minutes, processing temperature 80°C), and Experimental Example 16 (processing time 60 minutes, processing temperature 80°C), the lead concentration in the solution was below the environmental standard (less than 0.05 mg / L).

[0028] Next, in Experiment Example 8 (processing time 60 minutes, processing temperature 40°C) described above, the correlation between the concentration of the dilute sulfuric acid solution (0.1-0.3 mol / L) and the lead concentration in the solution was confirmed. The experimental results are shown in Table 2. [Table 2]

[0029] Regarding the effect of concentration, when the dilute sulfuric acid concentration was 0.1 mol / L, the lead concentration in the solution increased compared to when it was 0.2 mol / L. When the dilute sulfuric acid concentration was 0.3 mol / L, the lead concentration in the solution decreased compared to when it was 0.2 mol / L. From these results, it can be inferred that good results regarding the lead concentration in the solution can be obtained when the dilute sulfuric acid concentration is between 0.2 and 0.3 mol / L.

[0030] Furthermore, the precipitation-promoting effect (filtration-promoting effect) of cooling was confirmed for washing solvent 4 after removing the sparingly soluble lead compound (precipitate) obtained in Experimental Example 4 (dilute sulfuric acid concentration 0.2 mol / L, processing time 60 minutes, processing temperature 20°C). To promote the precipitation of lead compounds, the temperature of washing solvent 4 obtained in Experimental Example 4 was cooled to 5°C and 10°C, respectively, and stirred for an additional 10 minutes. The experimental results at this time are shown in Table 3. [Table 3]

[0031] As shown in Table 3, it was confirmed that the lead concentration in the liquid decreased significantly upon cooling.

[0032] Furthermore, the lead adsorption effect of washing solvent 4, after removing the sparingly soluble lead compound (precipitate) obtained in Experimental Example 5 (dilute sulfuric acid concentration 0.2 mol / L, processing time 10 minutes, processing temperature 40°C) described above, was confirmed using three types of heavy metal removal filters. The experimental results at this time are shown in Table 4. The ion exchange resin filter was AmberLite® IR120 H (Dow Chemical / DuPont), the activated carbon filter was AquaCarb® 1230C (Jacobs), and the silicate adsorption filter was MPX-Press Silica Gel (Merck / Sigma-Aldrich). [Table 4]

[0033] The ion exchange resin filter (Experimental Example 5A) showed the highest lead ion removal efficiency (99%), resulting in a lead concentration of 0.02 mg / L in the solution. The processing speed was moderate, making it suitable for large-scale processing. The activated carbon filter (Experimental Example 5B) reduced the lead concentration to 0.03 mg / L. While the removal efficiency was high at 97%, performance may degrade with long-term use. The silicate adsorption filter (Experimental Example 5C) reduced the lead concentration to 0.04 mg / L. Although the removal efficiency was somewhat lower at 95%, the processing speed was fast, making it suitable for efficient short-time processing. From these results, it is inferred that the ion exchange resin filter provides the most efficient and stable performance.

[0034] Furthermore, the lead sulfate (PbSO4) obtained in the above experiment was reprocessed into reusable lead oxide (PbO) by incineration (calcination). Three incineration conditions and their results are shown in Table 5. The sample was lead sulfate (PbSO4, weight 0.198g), and the lead oxide production rate, purity, and energy consumption were measured while changing the incineration conditions (incineration temperature, time, oxygen supply). [Table 5]

[0035] In Experiment 21 (500°C, 40 minutes), the decomposition of lead sulfate was incomplete, resulting in a lead oxide production rate of 85%. While a certain level of quality was achieved with a purity of 94%, the low production rate could be a challenge. Energy consumption was low, making it a potentially effective low-cost option. In Experiment 22 (600°C, 30 minutes), the decomposition of lead sulfate progressed, achieving a lead oxide production rate of 96% and a purity of 97%. The balance between processing time, production rate, purity, and energy consumption was good, making it seem industrially optimal. In Experiment 23 (700°C, 20 minutes), a lead oxide production rate of 98% and a purity of 99% were achieved. It is presumed that the sulfuric acid components were completely decomposed due to the high oxygen supply and temperature. [Explanation of symbols]

[0036] 1: Perovskite solar cell module 2: Transparent substrate 3: Functional Layer 4: Washing solvent 5: Ultrasonic transducer 6: Agitator 20 :Temperature 31:Transparent electrode layer 32: Electron transport layer 33: Perovskite photoelectric conversion layer 34: Hole transport layer 35: Back electrode layer 36: Sealing layer 37: Backseat layer 40: Container

Claims

1. A method for processing a perovskite solar cell module, comprising a dissolution step, a deposition step, and a solid-liquid separation step, The perovskite solar cell module includes a transparent substrate and a plurality of functional layers. The aforementioned plurality of functional layers include a perovskite photoelectric conversion layer, In the dissolution step, the perovskite solar cell module is immersed in a cleaning solvent and ultrasonic waves are applied to peel off the multiple functional layers from the transparent substrate, and the perovskite photoelectric conversion layer is dissolved in the cleaning solvent. In the precipitation step, the lead dissolved in the washing solvent is precipitated as a sparingly soluble lead compound. A method for processing a perovskite solar cell module, wherein the lead compound and the washing solvent are separated in the solid-liquid separation step.

2. A method for processing a perovskite solar cell module according to claim 1, A method for processing a perovskite solar cell module, wherein the cleaning solvent is a dilute sulfuric acid aqueous solution and the sparingly soluble lead compound is lead sulfate.

3. A method for processing a perovskite solar cell module according to claim 1 or 2, A method for processing a perovskite solar cell module, wherein in the dissolution step, the washing solvent is heated to 40 to 80°C.

4. A method for processing a perovskite solar cell module according to claim 3, A method for processing a perovskite solar cell module, wherein in the deposition step, the washing solvent is cooled to 10°C or below.

5. A method for processing a perovskite solar cell module according to claim 1, further comprising an adsorption step, A method for processing a perovskite solar cell module, wherein in the adsorption step, lead remaining in the washing solvent after the solid-liquid separation step is adsorbed by a lead removal filter.

6. A method for processing a perovskite solar cell module according to claim 1 or claim 5, A method for processing a perovskite solar cell module, wherein the lead content of the washing solvent after the solid-liquid separation step or the lead content of the washing solvent after the adsorption step is 0.05 mg / L or less.

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