JP2021023839A - Selective decomposition method and decomposition device for solar panel - Google Patents

Abstract

To provide selective decomposition method and decomposition device for solar panel by which decomposition can be performed with less work time, and useful substances can be selectively separated and concentrated with low environmental load and low cost.SOLUTION: According to this decomposition method and decomposition device for a solar panel 1 as a disposal object, a cover glass 3 is removed from a cell sheet 4, which constitutes the solar panel 1, by use of a hot knife, a plurality of electrodes 9 are brought into contact with each other at positions separated from a conductor 5 on the cell sheet 4, a voltage is applied between the plurality of electrodes 9 to selectively take out useful substances from the cell sheet 4 by electric pulse.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for selectively disassembling a solar panel by an electric pulse and a disassembling device.

In recent years, the installation of solar panels has progressed in Japan as well, and it has achieved a certain effect in reducing the load on the natural environment. However, the solar panel has a product life, and although it varies depending on the product, it reaches the practical life after about 20 years. Further, even before the product life is reached, the solar panel may not be usable due to partial or total damage due to a natural disaster such as an earthquake or a typhoon. Under these circumstances, it is expected that the amount of solar panels discarded will increase in the future.

Traditionally, communication terminal devices and home appliances that are no longer used due to breakdowns or changes in the product life cycle have been collected by vendors, then disassembled and disassembled for recycling and reuse. Communication terminal devices and home appliances were often physically disassembled by a crusher after being manually disassembled. However, such work requires a lot of manpower, and there is a problem in recycling and reusing parts after dismantling.

Under these circumstances, in recent years, various methods of decomposing waste objects by causing pulse power discharge in water have been proposed.

For example, Patent Document 1 describes the following invention. A method of subdividing a homogeneous non-metallic solid by crushing a non-metallic component or a solid partially condensed from a metallic component and rapidly discharging an electrical energy store, wherein the solid is non-conductive or Immersed in a weakly conductive treatment liquid, the treatment liquid is contained in a container, and in the treatment liquid, a device consisting of a high voltage electrode and an earth electrode is composed of the treatment liquid and a solid. A high voltage consisting of predetermined steps between the ends of the high voltage electrode and the ends of the ground electrode in a manner that projects into the mixture and the ends of the electrodes are spaced apart from each other. A method of crushing and subdividing a solid by applying a pulse and using a shock wave generated in a liquid.

Further, Patent Document 2 describes the following invention. A series of discharges is generated between at least two electrodes in the reactor containing the ambient liquid and the material and / or product to be reused, and the series of discharges is the result of the energy, frequency of the discharge, and the electrodes. A method for reusing a material and / or product with pulsed power that produces a mechanical shock wave propagating throughout the material and / or product to be processed in the reactor, depending on the voltage and switching time between them. After the first step of weakening by the generated mechanical shock wave, the discharge energy, the voltage between the electrodes that generate the discharge, and the switching so that the discharge crushes the material by the direct effect of the discharge. A method of exposing the material and / or product to a series of discharges of selected time and discharge frequency and drying the material and / or product by thermal induction by the generation of microwaves.

Further, Patent Document 3 describes the following invention. A method for fragmenting and / or weakening a pourable material using a high voltage discharge, a) corresponding to one or more high voltage generators, by said high voltage generator. A step of preparing an electrode unit capable of supplying a high voltage pulse and b) a material flow made of a pouring material are guided by a transport device carrying the material flow by passing by the electrode unit. High voltage by supplying a high voltage pulse to the electrode unit during the step of immersing the material flow in the treatment liquid and c) guiding the material flow by passing by the electrode unit. Each electrode of the electrode unit is immersed in the treatment liquid from above, and the insulation breakage due to the high voltage occurs in between. A method for fragmenting and / or weakening a pourable material, wherein each of the electrodes to be squeezed faces a predetermined electrode spacing in the lateral direction with respect to the material passage guide direction.

Further, as a method for recycling a solar cell module, Patent Document 4 describes the following invention. A method for recycling a solar cell module in which a glass material and a solar cell element are laminated and a sheet-shaped back surface protective material is adhered with a predetermined filler. The back surface protective material maintains the sheet shape. The crushing step of crushing the glass material and the solar cell element, the softening step of heating and softening the filler adhering to the crushed glass material and the solar cell element, and the crushing of the glass material and the solar cell element. The solar cell module includes a separation step of applying a blade to the softened filler to separate the back surface protective material, and a crushing step of crushing the glass material from which the back surface protective material is separated and the solar cell element. A method of recycling solar cell modules, which is characterized by this.

However, the invention described in Patent Document 1 crushes an object mainly by using a shock wave of water with an electrode fixed in water, and even an unnecessary part is crushed and selectively disassembled. There was a problem that I couldn't do.

Further, the invention described in Patent Document 2 also has a problem that the object in the reactor is totally pulverized and a specific part of the object cannot be selectively disassembled.

Further, in the invention described in Patent Document 3, the electrode position is fixed, the object is poured by a conveyor or the like, and the object is randomly discharged at a high voltage to be fragmented and weakened, and cannot be selectively disassembled. There was a problem.

Since all of the inventions described in Patent Documents 1 to 3 have high randomness with respect to the discharge path and are not selectively and locally disassembled, the number of irradiations of the high voltage pulse is increased. When the whole thing is disassembled, it will be crushed more finely than necessary. In addition, there is a problem that the amount of energy required for dismantling is large as unnecessary parts are disassembled into small pieces.

Further, in the invention described in Patent Document 4, the glass material of the solar cell module is mechanically crushed and heated to soften the filler to separate the glass material, and the amount of energy required for disassembly is large. There was also a problem in terms of resource recycling.

Japanese Unexamined Patent Publication No. 9-75769 Japanese Patent No. 5734875 Special Table 2018-506429 Japanese Patent No. 5574750

In light of the above circumstances, it is an object of the present invention to provide a method and an apparatus for disassembling a solar panel that can be disassembled in a short working time, has a low environmental load, is low in cost, and can selectively separate and concentrate useful substances. ..

The present invention is a method for disassembling a solar panel to be discarded, in which a plurality of electrodes are brought into contact with each other at positions separated from conductors on a cell sheet constituting the solar panel, and a voltage is applied between the plurality of electrodes. This is a method for disassembling a solar panel, characterized in that useful substances are selectively extracted from the cell sheet by applying an electric pulse.

Further, after peeling the cover glass from the solar panel without crushing, a plurality of electrodes are brought into contact with each other at positions separated from the conductors on the cell sheet, and a voltage is applied between the plurality of electrodes by an electric pulse. , A method for disassembling a solar panel, which comprises selectively extracting useful substances from the cell sheet.

Further, the dismantling method is characterized in that the cover glass is peeled off from the solar panel with a hot knife.

Further, the present invention is a device for disassembling a solar panel to be discarded, and is between a plurality of electrodes abutting at separated positions of conductors on a cell sheet constituting the solar panel and the plurality of electrodes. It is a solar panel disassembling device including an electric pulse generator for applying an electric pulse to the solar panel, and selectively extracting useful substances by causing the solar panel to explode with a thin wire in water or air.

According to the present invention, the solar panel to be discarded can be disassembled in a short working time. In addition, since the amount of energy required for dismantling is small, the solar panel can be dismantled at low cost and the environmental load is small. Furthermore, since useful substances such as silver and copper can be selectively separated and concentrated, they can contribute to the construction of a resource-recycling society.

It is a disassembly process flow chart of the solar panel to which this invention is applied. It is a top view which shows the schematic structure of a cell sheet. It is sectional drawing which shows the schematic structure of the solar panel. It is an external view which shows the state which the terminal is connected to the cell sheet. It is an external view which shows the disassembled state by 2nd Embodiment. It is an external view which shows the disassembled state by 3rd Embodiment. It is an enlarged view by SEM observation of a copper particle. It is an enlarged view by SEM observation of a copper particle. It is an enlarged view by SEM photograph of a silicon particle. It is an enlarged view by SEM photograph of a silicon particle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart of a dismantling process of a solar panel 1 to which the present invention is applied. The recovered used solar panel 1 is diagnosed as to whether or not it can be reused as it is (step 10), and the one that can be reused is reused as it is. If it is determined that the solar panel cannot be reused, the aluminum frame 2 as the outer frame protecting the solar panel 1 is removed (step 11).

Next, it is determined whether or not the cover glass 3 protecting the surface of the solar panel 1 is damaged (step 12). When the cover glass 3 is not damaged, the process proceeds to a glass plate cutting step in order to peel the glass from the cell sheet 4 so as not to damage the glass (step 13). The broken glass will be described later.

The process of cutting out the glass plate can be performed by the hot knife method already in practical use. In the hot knife method, for example, as disclosed in Japanese Patent Application Laid-Open No. 2016-203061, the glass plate is peeled off from the cell sheet 4 by using a blade (not shown) called a hot knife heated by a heater. .. It has the feature that the glass plate can be peeled off efficiently in a short time.

Even if the peeled glass plate does not seem to have scratches at first glance, it often has fine scratches on its surface and cannot be distributed as a flat glass product as it is. Therefore, after removing scratches by polishing the surface of the glass plate, it is distributed as a flat glass product. Those that cannot be regenerated by polishing are melted in a glass kiln as glass cullet and used as raw materials for glass.

The main object of application of the present invention is the cell sheet 4 after the glass plate 3 has been peeled off. The cell sheet 4 contains a large amount of useful substances such as silicon and metals having high economic value such as copper and silver. A feature of the present invention is that these useful substances can be efficiently recovered in a short time and with a small amount of energy. Specifically, a shock wave is generated by a thin wire explosion method, and a useful substance is recovered from the cell sheet 4 (step 14).

The thin wire explosion method itself is a technology that has been known for a long time. Generally, a copper wire or aluminum wire having a diameter of about 1 mm is discharged at once by discharging the electric charge charged in a capacitor having a large capacitance to copper. It explodes a wire or aluminum wire to obtain the required shock wave.

Therefore, in order to disassemble the object by applying the thin wire explosion method, it is necessary that the object is provided with a good conductor as a thin wire in advance. Here, conveniently, the cell sheet 4 of the solar panel 1 is provided with strip-shaped copper wires 5 at predetermined intervals.

FIG. 2 is a plan view showing a part of a silicon-based battery cell 6, and FIG. 3 is a cross-sectional view schematically showing a solar panel 1 in which the battery cell 6 is assembled. Since the size of each battery cell 6 is about 10 to 15 cm on a side, the generated power is small, and the voltage is low, the power should be taken out after connecting a plurality of battery cells 6 in series with a copper wire 5. It has become. In the actual solar panel 1, as shown in the cross-sectional view of FIG. 3, the cell sheet 4 is arranged between the back sheet 7 and the cover glass 3, and these members are used as an adhesive filler 8 for EVA (ethylene vinyl acetate). It is fixed and protected in place by a polymer).

[First Embodiment]
FIG. 4 shows a first embodiment. As shown in the photograph shown in FIG. 4A, the cell sheet piece 4 used in the experiment is obtained by cutting out approximately 43 mm in length × 53 mm in width from the cell sheet 4 of a used silicon-based solar cell. The cell sheet piece 4 includes a part of two battery cells 6 on the left and right, and a strip-shaped copper wire is provided at the center thereof. Terminals 9 for connecting to a stored capacitor that serves as a power source are attached to both ends of the copper wire (upper end and lower end in the figure). In this embodiment, after charging a capacitor having a capacitance of 40 μF with a voltage of 15 kV, the charged charge is discharged at once between both terminals 9 in the atmosphere. The amount of energy generated by this discharge is 4500 joules.

Although it is referred to as a copper wire here, the copper wire is formed in the manufacturing process of the battery cell and is not composed only of the Cu component. As shown in FIG. 4B, each component of Sn, Pb, and Ag is contained in addition to the Cu component. Specifically, the composition ratio is Cu78.8%, Sn8.7%, Pb4.4%, and Ag0.82%. The copper wire containing these useful substances contains 5.68 g / m ² per unit area in the cell sheet piece.

The entire cell sheet on which the battery cell is formed has a large amount of silicon component, but the component with the largest amount is to properly fix the battery cell between the back sheet and the cover glass and protect it from physical external force. EVA as an insulator. The composition ratio of each component is Cu 5.34%, Al 2.05%, Ag 0.09%, Si 19.55%, and an insulator 68.63%.

The upper surface of the cell sheet on which the battery cell is formed contains a large amount of Si component, but also contains Ag and Al components. Specifically, the composition ratio is Ag 0.11%, Si 40.81%, Al 0.62%, and an insulator 56.9%. These useful substances contain 26.7 g / m ^{2 per unit area.}

On the other hand, on the lower surface of the cell sheet, the composition ratio of Si is lower than that on the upper surface of the cell sheet, and the composition ratio of the insulator is higher. Specifically, the composition ratio is Ag 0.0%, Si 10.47%, Al 2.98%, and an insulator 82.2%. These useful substances contain 51.7 g / m ^{2 per unit area.}

[Second Embodiment]
FIG. 5 shows a second embodiment. The cell sheet piece 4 used in the experiment is the same as that used in the first embodiment. In this embodiment, after charging a capacitor having a capacitance of 2.4 μF with a voltage of 45 kV, the cell sheet piece 4 is submerged in a container filled with water, and 2430 joules are provided between the terminals 9 attached to the copper wire 5. Energy was applied instantly.

FIG. 5A shows the surface state of the cell sheet piece 4 remaining after the thin wire explosion, and the copper wire 5 provided in the vertical center portion of the cell sheet piece 4 is completely lost by the explosion. The cell sheet 4 on which the battery cell 6 is formed is only partially peeled off from the back sheet 7. The useful substances contained in the remaining cell sheet were Cu 0.21%, Al 3.19%, Ag 0.02%, Si 23.46%, and an insulator 69.8%.

FIG. 5B is a collection of suspended particles scattered in water due to a fine wire explosion in water. Analysis of the components of these suspended particles revealed that Cu was 33.9%, Al was 3.0%, Si was 55.3%, and Ag was 0.8%.

Comparing the amount of useful substances contained in the remaining cell sheet and the amount of suspended particles in water, most of Cu and Ag were suspended particles in water, and the amount contained in the remaining cell sheet was small. Most of Si is also suspended in water. Only about half of Al was suspended in water, and about half was contained in the remaining cell sheet.

When the cell sheet is exploded in water by the fine wire explosion method in this way, many useful substances can be efficiently recovered as suspended particles in water.

[Third Embodiment]
FIG. 6 shows a third embodiment. The cell sheet piece 4 used in the experiment is the same as that used in the first and second embodiments. In this embodiment, after charging a capacitor having a capacitance of 40 μF with a voltage of 15 kV, the cell sheet piece 4 is submerged in a container filled with water, and energy of 4500 joules is generated between the terminals 9 attached to the copper wire 5. Was applied instantly.

FIG. 6A shows the surface state of the cell sheet piece 4 remaining after the thin wire explosion, and is the position of the copper wire 5 arranged in the vertical center portion of the cell sheet piece 4 on the left and right cell sheets. 4 is divided. The back sheet 7 is also peeled off from the cell sheet 4. Here, the useful substances contained in the remaining cell sheet were Cu 0.09%, Al 1.67%, Ag 0.03%, Si 17.89%, and an insulator 78.0%.

FIG. 6B is a collection of suspended particles scattered in water due to a fine wire explosion in water. Analysis of the components of these suspended particles revealed that Cu was 50.9%, Al was 8.7%, Si was 31.9%, and Ag was 1.1%.

Comparing the amount of useful substances contained in the remaining cell sheet and the amount of suspended particles in water, most of Cu and Ag were suspended particles in water, and the amount contained in the remaining cell sheet was very small. .. In addition, most of Si and Al were suspended particles in water, and the amount contained in the remaining cell sheet was small. In the third embodiment, the amount of suspended particles in water is larger in all useful substances than in the second embodiment. This difference is considered to be due to the difference in the amount of energy of the thin wire explosion.

FIG. 7 shows the appearance of Cu particles taken out by sorting the suspended particles in water obtained in the second embodiment and the third embodiment by a shape sorting method which is an existing technique. The Cu component sublimated by the fine wire explosion is cooled in water, and the shape of the Cu particles is substantially spherical. Although the size of the particles is not constant, the diameter is generally several tens of μm.

FIG. 8 is an analysis of the components of the Cu particles shown in FIG. 7. Of the two Cu particles analyzed, one had 91.48% Cu in visual field 1 and the other had 89.56% Cu in visual field 3. As described above, it can be seen that the Cu component is formed as high-concentration particles. When the sorted and recovered Cu particles are purified and reused, if the particles have a high concentration of Cu components, the purification is easy and the economic efficiency is improved.

FIG. 9 shows the appearance of Si particles taken out by sorting the suspended particles in water obtained in the second embodiment and the third embodiment by a shape sorting method which is an existing technique. The Si component sublimated by the fine wire explosion is cooled in water, and the particles are agglomerated with a rough surface. Although the size of the particles is not constant, the long side is about 100 μm.

FIG. 10 is an analysis of the components of Si particles. Of the two Si particles analyzed, one had 98.50% Si in visual field 1 and 96.92% Si in visual field 2. The other one had 99.18% Si in the field of view 3. As described above, it can be seen that the Si component is formed as high-concentration particles. When the sorted and recovered Si particles are purified and reused, if the particles have a high concentration of Si components, the purification is easy and the economic efficiency is improved.

Next, in step 15 of FIG. 1, a glass with breakage will be described. Of the recovered solar panels 1, if the cover glass 3 is damaged and the glass 3 cannot be peeled off from the cell sheet 4, the copper wire 5 on the cell sheet 4 is used to cause a thin wire explosion. I can't. Therefore, separately, a thin wire explosion is performed using a copper wire or an aluminum wire having a small diameter of about 1 mm. In this case, the residue obtained from the solar panel dismantled by the thin wire explosion becomes metal scraps and the like and glass cullet. The metal scraps and the like can be recovered as high-concentration particles as in the second embodiment and the third embodiment described above. In addition, glass cullet can also be recovered as high-purity glass particles.

In the above-described embodiment, an example of a silicon-based solar panel has been described, but the solar panel to which the present invention can be applied is not limited to silicon-based, but is also applied to other solar panels such as compound-based and organic-based. it can. Further, in the above-described embodiment, the shape selection method is used as a method for selecting copper and silicon from the suspended particles in water, but other physics such as selection using the difference in specific gravity of the suspended particles in water is used. A specific sorting method can also be used.

The method for selectively disassembling the solar panel and the disassembling device according to the present invention can be used for recycling or reusing the solar panel to be discarded.

1 Solar panel 3 Cover glass (glass)
4 Cell sheet (cell sheet piece)
5 Conductor (copper wire)
9 Electrodes (terminals)

Claims (4)

A method of disassembling a solar panel to be discarded, in which a plurality of electrodes are brought into contact with each other at positions separated from conductors on a cell sheet constituting the solar panel, and a voltage is applied between the plurality of electrodes. A method for disassembling a solar panel, which comprises selectively extracting useful substances from the cell sheet by an electric pulse. After peeling the cover glass from the solar panel without crushing, a plurality of electrodes are brought into contact with each other at positions separated from the conductors on the cell sheet, a voltage is applied between the plurality of electrodes, and the electric pulse is applied. A method for disassembling a solar panel, which comprises selectively extracting useful substances from a cell sheet. The method for disassembling a solar panel according to claim 2, wherein the cover glass is peeled off from the solar panel with a hot knife. A device for disassembling a solar panel to be discarded, in which an electric pulse is applied between a plurality of electrodes abutting at separated positions of conductors on a cell sheet constituting the solar panel and the plurality of electrodes. A solar panel dismantling device including an electric pulse generator, wherein the solar panel is detonated in water or in the air to selectively take out useful substances.