阅读说明：本技术 太阳能电池模块的再利用方法以及再利用装置 (Method and apparatus for reusing solar cell module ) 是由 酒井纪行 原田秀树 于 2019-04-05 设计创作，主要内容包括：再利用方法适用于具备盖玻片(23)、电池层(21B)以及将它们密接的密封材料(24)的太阳能电池模块(20)。再利用方法将盖玻片(23)与密封材料(24)的界面加热至给定的温度范围,在该界面维持给定的温度范围的状态下从太阳能电池模块(20)的侧面对密封材料(24)施加力,从该界面剥离密封材料(24)以及电池层(21B)。(The recycling method is suitable for a solar cell module (20) provided with a cover glass (23), a cell layer (21B), and a sealing material (24) for closely contacting the cover glass and the cell layer. The interface between the cover glass (23) and the sealing material (24) is heated to a predetermined temperature range, and the sealing material (24) and the cell layer (21B) are peeled from the interface by applying a force to the sealing material (24) from the side surface of the solar cell module (20) while maintaining the interface in the predetermined temperature range.)

1. A method for recycling a solar cell module comprising a cover glass, a cell layer, and a sealing material for closely adhering the cover glass to the cell layer,

heating the interface of the cover glass and the sealing material to a given temperature range,

applying a force to the sealing material from the side surface of the solar cell module while the interface is maintained in the predetermined temperature range, and peeling the sealing material and the cell layer from the interface.

2. The method for recycling a solar cell module according to claim 1,

the given temperature range is above the softening temperature and below the melting temperature of the sealing material.

3. The method for recycling a solar cell module according to claim 2,

the sealing material is EVA (ethylene-vinyl acetate copolymer),

the given temperature range is 40 ℃ or more and 140 ℃ or less.

4. The method for recycling a solar cell module according to claim 3,

the force is applied through the partition plate and,

the spacer does not contact the boundary portion where the cover glass and the sealing material are separated at a second time point other than the first time point at which the spacer first contacts the side surface of the solar cell module.

5. The method for recycling a solar cell module according to claim 4,

the separator has a contact portion that comes into contact with the sealing material at the second point in time,

an angle formed by a tangent line of the contact portion and a surface of the cover glass is 36 ° or more and 51 ° or less.

6. The reuse method of a solar cell module according to claim 4 or 5,

setting a relative speed of the solar cell module and the separator to a given speed range in a direction parallel to the surface of the cover glass, and pressing a side surface of the solar cell module against the separator, thereby generating the force.

7. The method for recycling a solar cell module according to any one of claims 4 to 6,

the temperature of the separator is maintained at room temperature.

8. The method for recycling a solar cell module according to any one of claims 1 to 7,

the battery layer is a CIS type battery layer.

9. The method for recycling a solar cell module according to any one of claims 1 to 8,

after the sealing material and the battery layer are peeled off from the cover glass, the weight of the sealing material remaining on the cover glass is 9% or less of the weight of the cover glass.

10. The method for recycling a solar cell module according to any one of claims 1 to 9,

in the case of the solar cell module having a structure in which the cell layer is disposed on the substrate glass and the cell layer is sandwiched between the cover glass and the substrate glass, the sealing material, the cell layer, and the substrate glass are peeled from the cover glass while crushing the substrate glass by applying the force to the substrate glass.

11. The method for recycling a solar cell module according to claim 10,

dissolving the battery layer by immersing the sealing material, the battery layer and the substrate glass peeled off from the cover glass in a dissolving solution, and separating the substrate glass and the sealing material,

and recovering the substrate glass and the sealing material respectively.

12. The method for recycling a solar cell module according to claim 11,

the substrate glass and the sealing material are separately recovered by utilizing the weight difference between the substrate glass and the sealing material in the solution.

13. The reuse method of a solar cell module according to claim 12, wherein

The dissolving solution is a nitric acid solution.

14. The method for recycling a solar cell module according to any one of claims 11 to 13,

after the substrate glass and the sealing material are recovered from the solution, each material included in the battery layer is recovered by extraction from the solution.

15. A recycling device for a solar cell module comprising a cover glass, a cell layer, and a sealing material for closely adhering the cover glass to the cell layer,

the solar cell module recycling device comprises:

a heater that heats an interface of the cover glass and the sealing material to a given temperature range;

a separator that applies a force to the sealing material from a side surface of the solar cell module;

a driving section that generates a relative speed between the solar cell module and the spacer in a direction parallel to a surface of the cover glass; and

a control unit for controlling the heater and the drive unit,

the control portion sets the interface to the given temperature range by the heater,

the force is applied to the sealing material from the side surface of the solar cell module by the driving unit while the interface is maintained in the predetermined temperature range, and the sealing material and the cell layer are peeled from the interface.

16. The recycling apparatus of solar cell modules according to claim 15,

the heater heats the interface from the cover glass side to the given temperature range.

17. A cover glass for reuse detached from a solar cell module,

the disclosed device is provided with:

a glass body; and

a sealing material attached to the glass body,

the sealing material is a material that seals a cell layer within the solar cell module,

the weight of the sealing material is 9% or less of the weight of the glass body.

18. The cover slip of claim 17,

the sealing material is attached only to the edge of the glass body.

Technical Field

The present invention relates to a method and an apparatus for recycling a solar cell module.

Background

Solar power generation has attracted attention as power generation based on renewable energy. Accordingly, it is expected that a large number of solar cell modules will be installed in various places in the future. Therefore, attention is paid to a structure and a technique for reusing a used solar cell module.

In the reuse of solar cell modules, it is important how to realize the reuse at low cost and how to recover materials at high yield. The cost reduction of reuse can reduce the cost payment time, and the reuse cost can be included in the selling price of the product. In addition, the solar cell module includes various materials including rare metals and harmful substances. Therefore, if these materials can be recovered at a high yield, they can contribute to effective utilization of global resources, reduction in product cost, and non-diffusion of harmful substances.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-203061

Patent document 2: japanese patent No. 5574750

Disclosure of Invention

Problems to be solved by the invention

Patent document 1 discloses a technique of separating a glass substrate from other materials using a doctor blade (blade) for reuse of a solar cell module. However, the separation of the glass substrate from the other materials is performed by cutting the sealing material that is in close contact with both materials with a doctor blade. In this case, a large amount of the sealing material remains in close contact with the glass substrate after the separation. Therefore, the technique of patent document 1 requires a step of removing the sealing material remaining on the glass substrate. This step is a step of burning the sealing material at a high temperature for about 13 hours and thermally decomposing the sealing material, and as a result, the recycling cost becomes enormous and CO is generated₂The environmental load also increases.

Further, patent document 2 discloses a technique of separating a back surface protective material from a glass substrate by pressing a doctor blade against a sealing material softened by heating. However, this technique also uses a doctor blade to cut the sealing material that adheres the glass substrate and the back surface protective material. In this case, as in the technique disclosed in patent document 1, a large amount of the sealing material remains in close contact with the glass substrate after separation. Therefore, in the technique of patent document 2, in order to remove the sealing material remaining on the glass substrate, for example, a step of burning the sealing material at a high temperature for a long time and thermally decomposing the sealing material is required.

Embodiments of the present invention provide a technique for recycling a solar cell module that enables recovery of materials at low cost and high yield.

Means for solving the problem

The reuse method according to the embodiment of the present invention is suitable for a solar cell module including a cover glass, a cell layer, and a sealing material for closely contacting the cover glass and the cell layer. The reuse method heats an interface between the cover glass and the sealing material to a predetermined temperature range, applies a force to the sealing material from a side surface of the solar cell module while maintaining the predetermined temperature range at the interface, and peels the sealing material and the cell layer from the interface.

Effect of invention

According to the embodiments of the present invention, a technique for recycling a solar cell module capable of recovering a material at low cost and high yield can be realized.

Drawings

Fig. 1 is a diagram showing a first example of the recycling apparatus.

Fig. 2 is a diagram showing a second example of the recycling apparatus.

Fig. 3 is a diagram showing a modification of the separation apparatus.

Fig. 4 is a diagram showing a first example of a solar cell module.

Fig. 5 is a diagram showing an example of a battery layer.

Fig. 6 is a diagram showing a second example of the solar cell module.

Fig. 7 is a diagram showing a first example of the reuse method.

Fig. 8 is a diagram showing a comparative example of the reuse method.

Fig. 9 is a diagram illustrating a case of separation at a first time point in the method of fig. 7.

Fig. 10 is a diagram showing the separation at the first time point in detail.

Fig. 11 is a diagram showing a case of separation at a second time point in the method of fig. 7.

Fig. 12 is a diagram showing the second time point separation in detail.

Fig. 13 is a diagram showing a case of separation in the method of fig. 8.

Fig. 14 is a diagram showing a relationship between the module temperature and the adhesion of the sealing material.

Fig. 15 is a diagram showing a relationship between a contact angle of the separator and a residual sealing material.

Fig. 16 is a diagram showing a second example of the reuse method.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

In the embodiments, the structures and elements other than the main portions of the present invention are simplified or omitted for easy understanding of the description. In the drawings, the same elements are denoted by the same reference numerals. In the drawings, although the thickness, shape, and the like of each element are schematically shown, the actual thickness, shape, and the like are not shown.

< apparatus for recycling solar cell Module >

First, an example of a solar cell module recycling apparatus will be described.

Fig. 1 shows a first example of a recycling apparatus.

The solar cell module recycling apparatus 10 includes a heating device 11, a separation device 12, and a control unit 13 for controlling these devices.

The heating device (heater) 11 heats the solar cell module to be reused to a predetermined temperature range. For example, when the solar cell module includes a cover glass (cover glass), a cell layer, and a sealing material for closely contacting the cover glass and the cell layer, the heating device 11 is provided for the purpose of heating the interface between the cover glass and the sealing material to a predetermined temperature range, as described later. This is for peeling the sealing material together with the battery layer from the cover glass as described later.

Therefore, the heating device 11 preferably has a function of locally heating the interface between the cover glass and the sealing material. However, the heating device 11 may heat the entire solar cell module. This is because, in this case, the sealing material can be peeled off together with the cell layer from the cover glass by heating the solar cell module to a given temperature range and applying a force to the sealing material from the side thereof.

Thus, the type of the heating device 11 is not particularly limited. The heating device 11 can utilize a lamp heating type, a resistance heating type, a high-frequency heating type, an induction heating type, or the like.

The separating apparatus 12 has the following functions: the sealing material and the cell layer are peeled from the cover glass without cutting the sealing material with respect to the solar cell module heated to a predetermined temperature range by the heating device 11. The separating device 12 includes a table 121, a driving unit 122, and a partition plate 123. The table 121 is used to set or transport the solar cell module. The driving section 122 sets the relative speed of the solar cell module and the spacer 123 to a given speed range in a direction parallel to the surface of the cover glass or the table 121, and presses the side surface of the solar cell module against the spacer. For example, the driving unit 122 feeds out the solar cell module on the table 121 in a direction toward the separator 123 within a predetermined speed range.

The separator 123 applies a force to the sealing material from the side of the solar cell module. The spacer 123 is not limited to a shape, a fixed state, a movable state, and the like as long as it can apply a force to the sealing material. For example, in this figure, the partition plate 123 has a curved surface portion. The curved surface portion is effective for converting a force applied to the side surface of the solar cell module into a force for peeling the sealing material and the cell layer from the cover glass, that is, a force perpendicular to the surface of the cover glass. Further, the spacer 123 may be fixed or may be movable in a direction parallel to the surface of the cover glass, specifically, in a direction toward the solar cell module.

The control unit 13 includes a controller and a memory. The controller is, for example, a CPU, MPU, or the like. The memory is, for example, RAM, ROM, etc. The control unit 13 may be a unit incorporated in the reuse apparatus 10, or may be a general-purpose device such as a personal computer.

The controller 13 controls, for example, a predetermined temperature range in which the solar cell module is heated by the heating device 11 and a predetermined speed range in which the solar cell module is conveyed by the separating device 12, in order to peel the sealing material together with the cell layer from the cover glass. For example, the control unit 13 sets the predetermined temperature range to 40 ℃ or more and 140 ℃ or less. The control unit 13 sets the predetermined speed range to 24 mm/sec or less (excluding 0 mm/sec). The basis for setting these temperature ranges and speed ranges will be described later.

In addition, when the angle of the partition plate 123 (corresponding to a contact angle of a partition plate described later) can be changed around the rotation axis O and the temperature of the partition plate 123 can be changed, the control unit 13 may control at least one of the angle and the temperature of the partition plate 123. For example, the controller 13 can control the force with which the sealing material and the battery layer are peeled from the cover glass by controlling the angle of the spacer 123.

According to such a recycling apparatus, the sealing material and the battery layer can be peeled off from the interface between the cover glass and the sealing material by performing a recycling method described later. That is, in the reuse of the solar cell module, the cover glass is not crushed, and the sealing material hardly remains on the cover glass. Therefore, the glass material can be effectively reused, and the cover glass can also be directly reused.

Fig. 2 shows a second example of the recycling apparatus.

The recycling apparatus 10 of this example has a feature that, compared to the first example, the heating device is omitted and the heater 124 is provided in the separation device 12. Other points are the same as those in the first example, and therefore the same reference numerals as those used in fig. 1 are used in fig. 2, and detailed description thereof will be omitted.

The heater 124 is disposed directly below the stage 121. The heater 124 may be incorporated inside the table 121. The type of the heater 124 is not particularly limited, but a resistance heating type that can be miniaturized, for example, a hot plate or the like, is preferably used.

When the solar cell module to be reused is disposed on the table 121 with the cover glass side facing downward, the heater 124 can heat the solar cell module from the cover glass side. That is, the control unit 13 can easily set the interface between the cover glass and the sealing material of the solar cell module to a predetermined temperature range.

Therefore, if the reuse device of this example is used, the sealing force at the interface between the cover glass and the sealing material can be easily weakened. As a result, the sealing material and the battery layer can be peeled off from the interface between the cover glass and the sealing material by performing a recycling method described later.

Fig. 3 shows a modification of the separation device.

This modification can be applied to both the first example (fig. 1) and the second example (fig. 2).

This modification is characterized in that a roller 125 is provided instead of the table 121 in fig. 1 and 2. The roller 125 has an effect of facilitating conveyance of the solar cell module by the driving unit 122. In addition, when this modification is applied to the second example, the heaters 124 in fig. 2 may be provided between the rollers 125 in fig. 3, respectively, and the heating efficiency of the solar cell module may be improved.

< solar cell Module >

Next, an example of the solar cell module will be described.

The type of solar cell module that can be the subject of the present embodiment is not particularly limited. The solar cell module to be reused includes at least a cover glass, a cell layer, and a sealing material for closely contacting the cover glass and the cell layer.

Hereinafter, as examples of the solar cell module that can be the subject of the present embodiment, both a compound-based solar cell module and a silicon-based solar cell module will be described.

Fig. 4 shows a first example of a solar cell module.

The first example is an example of a compound-based solar cell module. The compound-based solar cell module has a feature that a thin film and a low cost can be achieved as compared with a silicon-based solar cell module.

The solar cell module 20 includes a cell group portion 21, a back plate 22, a cover glass 23, and a sealing material 24. The battery unit 21 includes a substrate glass 21A and a battery layer 21B on the substrate glass 21A. That is, the solar cell module 20 has a structure in which the cell layer 21B is sandwiched by 2 glass plates (the cover glass 23 and the substrate glass 21A).

The substrate glass 21A may be changed to a resin substrate, a metal substrate, a flexible substrate having flexibility, a flexible substrate having a laminated structure of stainless steel (SUS), aluminum, and alumina, for example. The substrate glass 21A may also include an alkali metal such as sodium or sodium.

The battery layer 21B has a function of converting light into electricity. Light is incident on the cell layer 21B from the cover glass 23 side. The battery layer 21B has, for example, the configuration shown in fig. 5.

In fig. 5, the battery layer 21B includes a first electrode layer 211 on the substrate glass 21A, a photoelectric conversion layer 212 on the first electrode layer 211, a buffer layer 213 on the photoelectric conversion layer 212, and a second electrode layer 214 on the buffer layer 213.

The first electrode layer 211 is, for example, a metal electrode layer. The first electrode layer 211 is preferably made of a material that is less likely to react with the photoelectric conversion layer 212. The first electrode layer 211 can be selected from molybdenum (Mo), titanium (Ti), chromium (Cr), and the like. The first electrode layer 211 may also include the same material as included in the second electrode layer 214. The thickness of the first electrode layer 211 is set to 200nm to 500 nm.

The photoelectric conversion layer 212 is a polycrystalline or microcrystalline p-type compound semiconductor layer. For example, the photoelectric conversion layer 212 includes a mixed crystal compound (I-III- (Se, S)2) having a chalcopyrite structure including a group I element, a group III element, selenium (Se) as a group VI element (chalcogen element), and sulfur (S). The group I element can be selected from copper (Cu), silver (Ag), gold (Au), and the like. The group III element can be selected from indium (In), gallium (Ga), aluminum (Al), and the like. The photoelectric conversion layer 212 may include tellurium (Te) as a group VI element in addition to selenium and sulfur. The photoelectric conversion layer 212 is formed to be thin and has a thickness of 1 μm or more and 1.5 μm or less.

The buffer layer 213 is, for example, an n-type or i (intrinsic) type high resistance conductive layer. The term "high resistance" as used herein means having a resistance value higher than the resistance value of the second electrode layer 214. The buffer layer 213 can be selected from compounds including zinc (Zn), cadmium (Cd), and indium (In). As the compound including zinc, there are, for example, ZnO, ZnS, Zn (OH)₂Or mixed crystals of these, such as Zn (O, S) and Zn (O, S, OH), ZnMgO, and ZnSnO. As the compound including cadmium, for example, CdS, CdO, or Cd (O, S), Cd (O, S, OH) as a mixed crystal thereof is given. Examples of the compound containing indium include InS and InO, and In (O, S) and In (O, S, OH) which are mixed crystals thereof. The buffer layer 213 may have a stacked structure of these compounds. The thickness of the buffer layer 213 is set to 10nm to 100 nm.

The buffer layer 213 has an effect of improving characteristics such as a photoelectric conversion ratio, but may be omitted. When the buffer layer 213 is omitted, the second electrode layer 214 is disposed on the photoelectric conversion layer 212.

The second electrode layer 214 is, for example, an n-type conductive layer. The second electrode layer 214 is preferably made of a material having a wide forbidden bandwidth and a sufficiently low resistance value, for example. The second electrode layer 214 is preferably a material that allows light of a wavelength that can be absorbed by the photoelectric conversion layer 212 to pass therethrough, because it serves as a light path for light such as sunlight. According to this meaning, the second electrode layer 214 is referred to as a transparent electrode layer or a window layer.

The second electrode layer 214 includes, for example, an oxide metal to which a group III element (B, Al, Ga, or In) is added as a dopant. Examples of the metal oxide include ZnO and SnO₂. The second electrode layer 214 can be made of, for example, ITO (indium tin oxide), ITiO (oxygen)Indium titanium oxide), IZO (indium zinc oxide), ZTO (zinc tin oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), and the like. The thickness of the second electrode layer 214 is set to 0.5 μm or more and 2.5 μm or less.

The explanation returns to fig. 4.

A back plate (back sheet)22 covers the back surface of the substrate glass 21A. Here, the back surface of the substrate glass 21A refers to a surface opposite to the surface on which the battery layer 21B is provided, of the two surfaces of the substrate glass 21A. The rear plate 22 is made of, for example, PET (polyethylene Terephthalate), metal foil (e.g., aluminum foil), or the like.

The sealing material 24 is disposed between the battery layer 21B and the cover glass 23. The cover glass 23 is, for example, a white plate tempered glass, a transparent resin plate, or the like. The sealing material 24 includes materials such as eva (ethylene Vinyl acetate), pvb (poly Vinyl butyl), and silicone resin. The sealing material 24 seals the battery layer 21B by applying pressure and heat, and the battery layer 21B and the cover glass 23 are brought into close contact with each other.

Fig. 6 shows a second example of the solar cell module.

The second example is an example of a silicon-based solar cell module.

The solar cell module 20 includes a cell group portion 21, a back plate 22, a cover glass 23, and a sealing material 24 for sealing the cell group portion 21. The sealing material 24 tightly adheres the rear plate 22 and the cover glass 23 to each other. That is, the battery pack portion 21 is sandwiched between the rear plate 22 and the cover glass 23.

The silicon-based solar cell module includes a cell group portion 21 including a silicon substrate as a cell layer. The cell group portion 21 is sealed with the sealing material 24 in the same manner as the cell layers in the compound-based solar cell module shown in the first example.

The rear plate 22, the cover glass 23, and the sealing material 24 are the same as those of the first example, and therefore, the description thereof is omitted here.

< method for reusing solar cell Module >

Next, an example of a method for reusing the solar cell module will be described.

First example

The first example relates to a method of peeling off a substrate glass from a solar cell module with substantially no sealing material remaining.

One of the technical issues in recycling of solar cell modules is how to effectively peel off a sealing material from a cover glass. For example, as described above, the sealing material such as EVA has a function of preventing moisture, dust, and the like from entering the battery pack portion by embedding the cover glass in the battery pack portion while closely contacting the cover glass. That is, the more reliable sealing is achieved, the more difficult it is to peel the sealing material from the cover glass.

Therefore, the present inventors have studied how to peel off the sealing material from the cover glass without leaving the sealing material on the cover glass, and as a result, have found that the temperature of the solar cell module, specifically, the temperature of the interface between the cover glass and the sealing material and the force applied to the solar cell module when peeling off the sealing material are important. Based on the relationship between the temperature and the force, there has been no idea of peeling the sealing material from the cover glass.

Fig. 7 shows a first example of a method for reusing a solar cell module.

The solar cell module 20 to be reused is provided with a cell group part 21, a cover glass 23, and a sealing material 24 for closely contacting them.

As shown in the drawing, in the present example, a cover glass separating step by peeling is performed to separate the solar cell module 20 into the cover glass 23, the other battery section 21, and the sealing material 24. Here, the cover glass separation step by peeling is a step of setting the interface between the cover glass 23 and the sealing material 24 to a predetermined temperature range and applying a force to the battery unit 21 from the side surface of the solar cell module 20 while maintaining the interface in the predetermined temperature range (step ST 01).

The interface between the cover glass 23 and the sealing material 24 is set to a predetermined temperature range in order to weaken the adhesion between the cover glass 23 and the sealing material 24. The sealing material 24 is not heated until it melts. In this example, the sealing material 24 is set to a softening temperature or higher and a melting temperature or lower. The force is applied to the battery unit 21 in order to peel the battery unit 21 and the sealing member 24 from the cover glass 23 starting from the portion to which the force is applied.

Thus, according to the method of the first example, the cover glass 23, the other battery pack portions 21, and the sealing material 24 can be easily and smoothly separated. Further, after the separation, the cover glass 23 is not crushed, and the sealing material 24 hardly remains on the cover glass 23. That is, the sealing material 24 is not present on the cover glass 23 at all or slightly remains at the edge portion thereof.

As a result, according to the method of this example, the cover glass 23 for reuse, which is decomposed from the solar cell module 20, can be provided such that the ratio of the weight of the sealing material 24 remaining in the glass body to the weight of the glass body is 9% or less. Here, the glass body means the cover glass 23 to which the sealing material 24 is not attached at all. Therefore, according to the method of this example, the glass material can be effectively reused from the cover glass 23, and the cover glass 23 can be directly reused.

Fig. 8 shows a comparative example of a method for reusing a solar cell module.

The comparative example relates to a technique of cutting the sealing material 24 with a spatula because it is difficult to peel the sealing material 24 from the cover glass 23. In fig. 8, the same elements as those in fig. 7 are denoted by the same reference numerals in fig. 8, thereby facilitating comparison between the two elements.

Conventionally, the battery unit 21 and the cover glass 23 are generally separated by a cover glass separation step by cutting without peeling the sealing material 24 from the cover glass 23. Here, the cover glass separation step by cutting is a step of separating the battery unit 21 and the cover glass 23 by cutting the sealing material 24 with a spatula (step ST 11).

However, in this case, a large amount of the sealing material 24 remains on the cover glass 23. In addition, a plurality of fine irregularities (embossings) are provided on the surface of the cover glass 23 in order to efficiently guide sunlight to the battery unit 21. That is, it is extremely difficult to physically remove the sealing material 24 remaining in the concave portion of the cover glass 23. Therefore, in the comparative example, it is necessary to further perform the sealing material removing step on the cover glass 23 obtained in the cover glass separating step by cutting (step ST 12).

The sealing material removing step is, for example, a step of burning the sealing material 24 at a high temperature for about 13 hours and thermally decomposing the sealing material, and as a result, the recycling cost becomes enormous and CO is generated₂The environmental load also increases.

As described above, according to the first example of the method for reusing the solar cell module, as is apparent from the comparison between fig. 7 and 8, the sealing material and the cell group portion can be peeled off from the cover glass based on the temperature of the solar cell module and the force applied to the solar cell module. Therefore, according to this example, a technique of recycling a solar cell module capable of recovering a material at low cost and high yield can be realized.

Next, a first example of a method for reusing a solar cell module will be described in detail with reference to fig. 9 to 13. In fig. 9 to 13, the same elements as those shown in fig. 1 to 8 already described are denoted by the same reference numerals, and detailed description thereof is omitted.

First, the back sheet 22 is removed from the solar cell module 20 shown in fig. 4 or 6, for example. Thereafter, the solar cell module 20 is set to a predetermined temperature range, for example, a temperature of 40 ℃ to 140 ℃ using the heating device 11 of fig. 1 or the heater 124 of fig. 2. This weakens the bonding force between the cover glass 23 and the sealing material 24.

Thereafter, as shown in fig. 9, the separator 123 is pressed against the side surface of the solar cell module 20. For example, in a state where the spacer 123 is stationary, the solar cell module 20 is moved in a direction parallel to the upper surface of the table 121, and as a result, the spacer 123 is pressed against the side surface of the solar cell module 20. This time point is the first time point at which the separator 123 is initially in contact with the side of the solar cell module 20. At this time, the battery pack portion 21, i.e., the substrate glass 21A and the battery layer 21B are forced from the separator 123.

For example, as shown in fig. 10, when the separator 123 has a curved surface portion, the battery pack portion 21 receives a force F from the separator 123 when the curved surface portion comes into contact with the battery pack portion 21. A part of the force F becomes a force Fup of peeling the battery portion 21 together with the sealing member 24 from the cover glass 23. Therefore, as shown in fig. 11, the battery pack portion 21 and the sealing member 24 are peeled from the cover glass 23 starting from the contact portion between the separator 123 and the battery pack portion 21.

Here, as shown in fig. 11, the battery pack portion 21 is peeled from the cover glass 23 while being crushed. Therefore, as shown in fig. 7, the battery pack portion 21 and the sealing material 24 separated from the cover glass 23 become glass chips. The method for collecting the material in the battery pack portion 21 and the sealing material 24 from the glass cullet will be described later.

Further, as shown in fig. 11, when the separator 123 enters between the battery section 21 and the cover glass 23, the contact portion of the separator 123 with the battery section 21 also changes. The time point is a second time point other than the first time point. At this time, as shown in fig. 12, in the contact portion P, the battery pack portion 21 receives a force F from the separator 123. The angle (contact angle) θ formed by the tangent line L of the contact portion P and the surface of the cover glass 23 is preferably 36 ° or more and 51 ° or less, for example. The basis for this is as follows.

Further, at the second point of time, the spacer plate 123 does not contact the boundary portion X where the cover glass 23 and the sealing material 24 are separated.

Here, the case of separation in the comparative example of fig. 8 is briefly described.

As shown in fig. 13, in the comparative example, the battery section 21 is separated from the cover glass 23 using a scraper (e.g., a heat seal knife) 126. This separation is performed by cutting the sealing material 24 with a blade 126. At this time, the scraper 126 is always in contact with the boundary portion X where the cover glass 23 and the sealing material 24 are separated.

In this way, by feeding the solar cell panel 20 toward the spacer 123 with the cover glass 23 facing downward and pressing the side surface of the solar cell panel 20 against the spacer 123, only the cover glass 23 remains on the table 121 and flows directly, and the other battery pack portion 21 and the sealing material 24 are separated as glass cullet from the cover glass 23.

Further, since the sealing material 24 hardly remains on the cover glass 23, the cover glass 23 can be recovered in a short time at low cost. Further, the cover glass 23 can be reused as it is.

Further, if the method of this example is used, the effect of reducing the amount of the sealing material 24 remaining on the cover glass 23 can be obtained as compared with the conventional method. The amount of the sealing material 24 remaining on the cover glass 23, that is, the degree of the effect of the method of this example, varies depending on various parameters (module temperature, contact angle of the separator, conveyance speed of the solar cell module, separator temperature, and the like). This point will be described later.

Experimental example

Next, an example of a parameter for determining the degree of the effect according to the first example will be described. The numerical limitations in the parameters explained below are based on experimental results. The solar cell module to be reused has a CIS solar cell module as a representative example of a compound solar cell module, and has a structure shown in fig. 4 (a state in which the rear plate 22 is removed).

[ Module temperature ]

Fig. 14 shows the relationship between the module temperature and the sealing force of the sealing material.

In order to prevent moisture, dust, and the like from entering the battery unit, the sealing material has a function of firmly adhering the cover glass to the battery unit at Room Temperature (RT). Therefore, the adhesion of the sealing material at room temperature, for example, about 20 ℃ is set to 100%, and how the adhesion changes is verified by the module temperature.

According to this figure, the sealing force of the sealing material, that is, the sealing force with respect to the cover glass decreases as the module temperature, that is, the temperature of the interface between the cover glass and the sealing material increases. Wherein the sealing material is EVA. For example, when the module temperature reaches 40 ℃, the sealing force of the sealing material is reduced to about half (about 50%) of the sealing force at room temperature. Further, when the module temperature reached 60 ℃, the sealing force of the sealing material was reduced to about 25% of the sealing force at room temperature, and when the module temperature reached 120 ℃, the sealing force of the sealing material was reduced to about 10% of the sealing force at room temperature.

In the cover glass separation step by the above-mentioned peeling, it is preferable that the adhesion force of the sealing material is as low as possible, but if the adhesion force is approximately 50% or less of the adhesion force at room temperature, it is possible to recover a cover glass that is not a hindrance to reuse of the glass material, as will be described later. Here, the cover glass with no obstacle to reuse of the glass material means a cover glass with a residual sealing material weight ratio of 9% or less. When the weight of the cover glass is a and the weight of the sealing material remaining on the cover glass is B, the weight ratio of the remaining sealing material is defined as (B/a) × 100 "%".

Therefore, when the sealing material is EVA, the module temperature is preferably 40 ℃ or higher in order to recover the cover glass substantially without hindrance. As described above, the sealing material must have a softening temperature or higher and a melting temperature or lower. In view of this, in the case of EVA, the module temperature is preferably 140 ℃ or less. As a result, the following effects can be obtained: when the module temperature is in the range of T1, i.e., 40 ℃ or higher and 140 ℃ or lower, the collection of the cover glass can be easily performed.

In addition, when the sealing material is EVA, the module temperature is preferably in the range of T2, that is, 60 ℃ to 140 ℃ inclusive, in order to further recover the cover glass without hindrance. Further, as described later, in order to obtain the maximum effect of the cover glass separation step by the above-described peeling while achieving a weight ratio of the residual sealing material of 3% or less, the module temperature is within the range of T3, that is, 120 ℃ or higher and 140 ℃ or lower.

Next, it was verified how the weight ratio of the residual sealing material, which is an index showing the effect of the first example, changes depending on parameters other than the module temperature.

[ contact angle of separator ]

Fig. 15 shows the relationship between the contact angle of the separator and the residual sealing material.

The contact angle of the separator is an angle formed by a tangent line at a contact portion of the separator and the battery unit portion and a surface of the cover glass (or a surface of the stage). For example, as shown in fig. 12, an angle θ formed by a tangent L at the contact portion P and the surface of the cover glass 23 is defined as a contact angle of the spacer.

The contact angle of the separator can be changed by changing the shape of the separator, particularly the shape of the curved surface portion, or by changing the angle of the separator when the side surface of the solar cell module is pressed against the separator. Further, the angle of the separator when the side surface of the solar cell module is pressed against the separator can be easily changed when the separator 123 can be rotated about the rotation axis O, as shown in fig. 1, for example.

In the figure, the horizontal axis represents the module temperature [ ° c ], and the vertical axis represents the weight ratio (B/a) × 100 [% ] of the residual sealing material. In the range of the module temperature T1(40 ℃ C. to T1 ℃ C. to 140 ℃ C.) in which the effects of the first example were obtained, the contact angle of the separator required to reduce the weight ratio of the residual sealing material to 9% or less was examined.

The contact angles of the separators were prepared in 4 kinds (36 °, 41 °, 46 °, 51 °). As can be seen from this figure, the weight ratio of the residual sealing material is 9% or less in the range where the contact angle of the separator is 36 ° or more and 51 ° or less. From this figure, it is understood that the weight ratio of the remaining sealing material is the largest at the point (40 ℃) where the module temperature is the lowest. Also, at a module temperature of 40 ℃, the contact angle of the separator where the weight ratio of the remaining sealing material is the largest was 36 ° (minimum) and 51 ° (maximum).

That is, if the contact angle of the separator is less than 36 ° or exceeds 51 °, it is easy to predict that the weight ratio of the residual sealing material may exceed 9% in the range where the module temperature is T1. Therefore, in order to obtain the effect that the weight ratio of the residual sealing material is 9% or less in the range of the module temperature T1, the contact angle of the separator is preferably 36 ° or more and 51 ° or less.

As described with reference to fig. 14, the module temperature in the range T3 of 120 ℃ to 140 ℃ has the effect of minimizing the adhesion of the sealing material (EVA). Therefore, in fig. 15, it is understood that the contact angle of the separator is 36 ° or more and 51 ° or less, and the weight ratio of the residual sealing material can be 3% or less, when the weight ratio of the residual sealing material in the temperature range T3 is determined by the contact angle of the separator. Therefore, in order to obtain the effect that the weight ratio of the residual sealing material is 3% or less in the range of the module temperature T3, the contact angle of the separator is preferably 36 ° or more and 51 ° or less.

[ other parameters ]

The parameters that determine the degree of the effect of the first example described above include the module temperature and the contact angle of the separator, as well as the transport speed of the solar cell module, the separator temperature, and the like.

In the reuse of the solar cell module, as described above, the relative speed of the solar cell module and the separator is set to a given speed range in the direction parallel to the surface of the cover glass, and the side surface of the solar cell module is pressed against the separator. Therefore, the relationship between the predetermined speed range, for example, the conveying speed of the solar cell module (the case where the separator is stopped) and the weight ratio of the residual sealing material was verified. As a result, in order to obtain the effect that the weight ratio of the residual sealing material is 9% or less in the range of the module temperature T1, the carrying speed of the solar cell module can be 24mm/s or less (except 0mm/s, herein).

That is, it was found that the slower the carrying speed of the solar cell module, in other words, the slower the speed of peeling the sealing material from the cover glass, the smaller the amount of the sealing material remaining on the cover glass. However, if the transportation speed of the solar cell module is slow, the throughput during reuse may be deteriorated. Therefore, considering the throughput, the transport speed of the solar cell module can be set to, for example, 3mm/s or more and 24mm/s or less.

The separator temperature also has an effect on the weight ratio of the residual sealing material. However, when the weight ratio of the remaining sealing material is verified by experiments, the weight ratio of the remaining sealing material is not affected as long as the temperature of the separator is not extremely increased. For example, if the separator temperature exceeds about 200 ℃, the weight ratio of the remaining sealing material is extremely increased in a direction in which peeling of the sealing material is deteriorated from a time point exceeding about 140 ℃. This is considered to be one reason why detachment of acetic acid in the sealing material (EVA) occurs if the separator temperature exceeds about 140 ℃.

Therefore, the temperature of the separator is preferably 140 ℃ or lower, as in the case of the module temperature. As described above, this is matched with the case where the weight ratio of the residual sealing material can be set to 9% or less at the module temperature of 140 ℃. The separator is used to separate the battery pack portion from the cover glass together with the sealing material, and the adhesion of the sealing material is adjusted according to the temperature of the module. That is, the temperature of the separator is sufficient as long as it is maintained at room temperature, and is preferable from the viewpoint of controllability of the recycling method and the effect of the present embodiment.

As described above, according to the first example, the cover glass that is not an obstacle to reuse of the glass material can be easily collected. That is, according to the first example, it is possible to realize a technique for recycling a solar cell module that can recover a material at low cost and high yield.

Second example

A second example relates to the overall flow of the method for recycling a solar cell module including the method according to the first example described above. The second example is a technique of recovering all materials constituting solar cell modules to be reused at high yield and low cost with low environmental load.

The recycling method according to the second example includes the following 3 steps.

1) Cover glass separating process (step ST01)

2) Removing (liftoff) process (step ST02)

3) Extraction procedure (step ST03)

The cover slip separating step (step ST01) is a cover slip separating step of peeling which has been described with reference to fig. 7 and 9 to 12. In this step, the solar cell module is separated into the cover glass and other glass cullet (the cell group portion and the sealing material). The removing step (step ST02) is a step of dissolving the battery layer in the battery pack portion using a dissolving solution to collect the substrate glass and the sealing material from the glass cullet. Further, the extraction step (step ST03) is a step of extracting various materials included in the solution from the solution including the dissolved battery layer to recover the various materials included in the solution.

The removal step (step ST02) and the extraction step (step ST03) are also referred to as liquid phase reuse steps because they use a solution.

A method for reusing the solar cell module according to the second example will be described below with reference to fig. 16. The solar cell module to be reused is a CIS solar cell module, and has a structure shown in fig. 4 (including a state of a frame (not shown)).

First, in the frame removal step, the frame is removed from the solar cell module 20 to be reused. Here, the frame is made of a material such as aluminum or aluminum alloy. Subsequently, the back sheet is peeled from the solar cell module 20 in the back sheet removing step. The frame removing step and the rear plate removing step are performed by a known method.

Next, the cover glass 23 is peeled off from the solar cell module 20 by the cover glass separation process (step ST 01). As described above, the ratio of the weight of the sealing material 24 remaining in the glass body to the weight of the glass body in the cover glass 23 obtained by this step is, for example, 9% or less. Therefore, the amount of the sealing material remaining in the cover glass 23 is small, and as a result, the glass material can be effectively reused from the cover glass 23, and the cover glass 23 can be directly reused.

On the other hand, the glass cullet other than the cover glass 23 obtained by the cover glass separation step includes the battery unit 21 and the sealing material 24. The battery pack portion 21 includes, for example, a substrate glass 21A and a battery layer 21B. For example, as shown in fig. 5, the battery layer 21B includes a first electrode layer 211, a photoelectric conversion layer 212, a buffer layer 213, and a second electrode layer 214. The photoelectric conversion layer 212 includes, for example, Cu (In)_x、Ga_1-x)(Se_y、S_1-y)₂Wherein x is more than or equal to 0 and less than or equal to 1, and y is more than 0 and less than 1. A photoelectric conversion layer as a main part of the cell layer 21BWhen 212 includes Cu, In, and Se, the cell layer 21B is generally referred to as a CIS type.

Thus, the broken substrate glass 21A, the battery layer 21B, and the sealing material 24 are in close contact with each other. Therefore, the glass cullet passes through the removal process (step ST02), dissolves the battery layer 21B with the dissolving liquid 31, thereby separating into the broken substrate glass 21A, the sealing material 24, and the dissolving liquid 31 including the dissolved battery layer 21B.

For example, when the dissolving liquid 31 is a nitric acid solution, the CIS-type battery layer 21B is dissolved in the nitric acid solution, for example. On the other hand, the substrate glass 21A and the sealing material 24 sandwiching the battery layer 21B are not dissolved in the nitric acid solution, and are thus separated from each other in a solid state (removing step). Further, the substrate glass 21A is in a state of sinking into the bottom of the nitric acid solution tank 32 due to its heavy weight, and is in a state of floating on the upper portion of the nitric acid solution tank 32 due to its light weight of the sealing material 24.

Therefore, the substrate glass 21A and the sealing material 24 are separated from each other by a removal step of immersing the glass cullets in the solution 31, and are collected. In addition, in the removal step, the CIS-type battery layer 21B is recovered in a state of being dissolved in the dissolving solution 31 (liquid phase recycling step).

Finally, an extraction step is performed to recover various materials from the solution 31 from which the substrate glass 21A and the sealing material 24 have been removed (step ST 03). When copper (Cu), indium (In), selenium (Se), gallium (Ga), sulfur (S), zinc (Zn), and the like included In the CIS type cell layer 21B are sequentially recovered by this extraction step, the recovery rates thereof can be 90% or more.

Conventionally, the recovery of the CIS type battery layer is performed by, for example, grinding the battery layer to produce a powder (powder recovery step). The recovery rate of each material obtained in the powder recovery step is limited to 1% or less in terms of improvement in purity due to the properties of the powder. In view of such circumstances, the liquid phase reuse process is a very excellent technique because the recovery rate of various materials included in the battery layer is remarkably improved.

Further, since selenium is a harmful substance, it is also preferable to recover selenium at a high recovery rate by a liquid phase reuse step from the viewpoint of non-diffusion of the harmful substance. In the liquid phase recycling step, a chemical solution, for example, a nitric acid solution, which dissolves the CIS type battery layer 21B is used as the dissolving solution 31. This means that, for example, an organic solvent for dissolving the sealing material 24 such as EVA may not be used.

According to the method for recycling a solar cell module using the above-described cover glass separation step, removal step, and extraction step, the recycling cost required for recovering various materials can be 40 yen/kg or less, specifically, about 34 yen/kg. In the case of the conventional method (fig. 8+ powder recovery step), the recycling cost required for recovering each material is about 57 yen/kg, and therefore the method according to the second example is very effective also in terms of the recycling cost.

The value of about 34 yen/kg corresponds to 4.1 yen/W when converted to a cost of 1W of rated output of the solar cell module. That is, assuming that the manufacturing cost per 1W rated output of the solar cell panel is 60 to 70 yen/W, the reuse cost can be 1 or less of the manufacturing cost.

< summary >

As described above, according to the embodiments of the present invention, it is possible to realize a technique for recycling a solar cell module capable of recovering a material at low cost and in high yield.

That is, according to the cover glass separating step, the cover glass can be recovered at low cost and high yield, and the firing/decomposition step of the sealing material is not required, so that CO does not emit₂The environmental load can also be reduced. Further, according to the removal process, the substrate glass can be recovered at low cost and in high yield, and the safety can be improved because an organic solvent is not used. Further, according to the removing step, the sealing material is not decomposed, and therefore the sealing material can be recovered. Furthermore, by chemically extracting various materials from the solution in accordance with the extraction step, it is possible to recover various materials included in the battery layer at low cost and in high yield, and also to recover various materials included in the battery layer at low cost and in high yieldThe effect of non-diffusion of the harmful substance can be achieved.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the present invention. These embodiments may be implemented in various ways other than those described above, and various omissions, substitutions, and changes may be made without departing from the spirit of the present invention. These embodiments and modifications are included in the scope and gist of the present invention, and inventions described in claims and equivalents thereof are also included in the scope and gist of the present invention.

The application claims that the priority of the Japanese patent application No. 2018-080716, which is submitted in 2018, 4, 19 and is based on the priority, and the whole contents of the Japanese patent application No. 2018-080716 are introduced into the application.

Description of the symbols

10: solar cell module recycling device, 11: heating device, 12: separation device, 121: table, 122: drive unit, 123: separator, 124: heater, 125: roller, 126: scraper, 13: control unit, 20: solar cell module, 21: battery pack portion, 21A: substrate glass, 21B: battery layer, 211: first electrode layer, 212: photoelectric conversion layer, 213: buffer layer, 214: second electrode layer, 22: rear plate, 23: cover glass, 24: sealing material, 31: dissolution solution, 32: a groove.