Solar cell module

Abstract

A solar cell module (10) according to the present invention is provided with: a solar cell string (1); a first protection plate (2) which is translucent and is superposed on the light incident surface side of the solar cell string (1); a second protection plate (3) which is superposed on a side of the solar cell string (1), the side being on the reverse side from the light incident surface; a sealing material (4) which is arranged between the first protection plate (2) and the second protection plate (3) so as to seal the solar cell string (1); a water absorbent layer (5) which is arranged between the sealing material (4) and the first protection plate (2) and / or between the sealing material (4) and the second protection plate (3). With respect to this solar cell module (10), the sealing material (4) contains a polyolefin elastomer resin, while the water absorbent layer (5) contains an ionomer resin.

Description

Cross - reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2022 - 057379, and the disclosure content thereof is incorporated into the description of this application by reference.

Technical Field

[0002] The present invention relates to a solar cell module.

Background Art

[0003] Conventionally, a solar cell module is known that includes a solar cell string formed by connecting a plurality of power - generating cells to each other, a first protective plate having translucency (for example, a glass plate, etc.) overlapped on the light - incident surface side of the solar cell string, a second protective plate (for example, a glass plate, etc.) overlapped on the side opposite to the light - incident surface of the solar cell string, and a sealing material disposed between the first protective plate and the second protective plate to seal the solar cell string.

[0004] The above - described solar cell module is usually manufactured by sandwiching the solar cell string from above and below with two sealing sheets including a sealing layer containing a sealing resin, disposing the first protective plate on the sealing layer of one sealing sheet, disposing the second protective plate on the sealing layer of the other sealing sheet, and then pressing from the first - protective - plate side and the second - protective - plate side. That is, in the above - described solar cell module, the sealing material is formed by the sealing layers of two sealing sheets.

[0005] The above - described solar cell module is often installed and used on the wall surface of a building such as a building or on the roof of a building such as a house. That is, the above - described solar cell module is often used in an environment where it can be exposed to rain, snow, etc. When moisture caused by rain, snow, or the like enters the interior of the solar cell module, the sealing layer peels off from the first protective plate, and cloudiness is confirmed when viewed from the side of the first protective plate. When the sealing layer peels off from the first protective plate, it is not preferable because it promotes the entry of moisture into the interior of the solar cell module. Also, as described above, when the solar cell module is installed and used on the wall surface of a building such as a building, cloudiness confirmed when viewed from the side of the first protective plate is not preferable from the viewpoint of aesthetics.

[0006] Therefore, in order to suppress the entry of moisture caused by rain, snow, or the like into the interior of the solar cell module, in Patent Document 1 below, the sealing layer of the sealing sheet is configured as a laminate of an ionomer layer containing an ionomer resin excellent in water absorption and an adhesive layer containing a polyolefin elastomer resin excellent in adhesiveness. It is disclosed that And in Patent Document 1 below, as an example of sandwiching the solar cell string with two sealing sheets configured as described above, the following are disclosed. · The sealing layer of the sealing sheet is a three-layer laminate in which adhesive layers are laminated on both sides of the ionomer layer, and the solar cell strand is sandwiched between the adhesive layers of one of the two sealing sheets (hereinafter, also referred to as the first aspect) · The sealing layer of the sealing sheet is a two-layer laminate in which an adhesive layer is laminated on one side of the ionomer layer, and the solar cell strand is sandwiched between the ionomer layers of the two sealing sheets (hereinafter, also referred to as the second aspect)

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Incidentally, as described above, the solar cell module is manufactured by pressing from the first protective plate side and the second protective plate side. The first protective plate and the second protective plate usually have a rectangular shape. When pressing is performed as described above, the four corners of the first protective plate and the four corners of the second protective plate are not necessarily sufficiently pressure-bonded to the sealing layer compared to the central portions of the first protective plate and the second protective plate, and slight gaps are formed at the four corner portions. Therefore, moisture caused by rain, snow, etc. enters the inside of the solar cell module through the slight gaps formed at the four corner portions. In the first aspect of Patent Document 1 described above, since the solar cell module is configured such that the adhesive layer is in contact with the first protective plate and the second protective plate, it is not always possible to sufficiently suppress the intrusion of moisture from the four corner portions.

[0009] In addition, an ionomer resin does not necessarily exhibit sufficient elasticity unless the types of polymers and the ion content constituting the ionomer resin are appropriately controlled. Therefore, when pressing with the solar cell strands sandwiched between ionomer layers as in the second aspect of Patent Document 1 described above, there is a risk of damage such as cracking in the power generation cells constituting the solar cell string because the ionomer layer does not exhibit sufficient elasticity. In addition, there is a risk of damage occurring at the connection portion of the power generation cells. That is, there is a risk of damage to the solar cell string.

[0010] However, it is difficult to say that sufficient consideration has been given to suppressing the intrusion of moisture into the solar cell module while reducing the risk of damage to the solar cell string.

[0011] Therefore, an object of the present invention is to provide a solar cell module that can suppress the intrusion of moisture into the interior while reducing the risk of damage to the solar cell string.

Means for Solving the Problems

[0012] The solar cell module according to the present invention includes a solar cell string, a first protective plate having translucency, which is overlapped on the light incident surface side of the solar cell string, a second protective plate, which is overlapped on the side opposite to the light incident surface of the solar cell string, a sealing material disposed between the first protective plate and the second protective plate to seal the solar cell string, and a water absorption layer disposed on at least one of the spaces between the sealing material and the first protective plate and between the sealing material and the second protective plate. The sealing material contains a polyolefin elastomer resin, and the water absorption layer contains an ionomer resin.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, an embodiment of the present invention may sometimes be simply referred to as this embodiment.

[0015] [Solar Cell Module] As shown in FIGS. 1 and 2, the solar cell module 10 according to this embodiment includes a solar cell string 1, a first protective plate 2 having translucency and superposed on the light incident surface side of the solar cell string 1, a second protective plate 3 superposed on the side opposite to the light incident surface of the solar cell string 1, a sealing material 4 disposed between the first protective plate 2 and the second protective plate 3 to seal the solar cell string 1, and a water absorption layer 5 disposed on at least one of the space between the sealing material 4 and the first protective plate 2 and the space between the sealing material 4 and the second protective plate 3. In the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the water absorption layer 5 is disposed only between the sealing material 4 and the second protective plate 3. That is, in the solar cell module 10 according to the present embodiment, the water absorption layer 5 is disposed only on the side opposite to the light incident surface of the solar cell string 1. In the solar cell module 10 according to the present embodiment, the sealing material 4 contains a polyolefin elastomer resin. In the solar cell module 10 according to the present embodiment, the water absorption layer 5 contains an ionomer resin.

[0016] In the solar cell module 10 according to the present embodiment, the sealing material 4 is configured as a sealing layer. Further, as shown in FIGS. 1 and 2, the solar cell module 10 according to the present embodiment is disposed between the solar cell string 1 and the first protective plate 2 having translucency, and further includes a decorative layer 6 that reduces or blocks part of the light transmitted through the first protective plate 2 having translucency.

[0017] In the solar cell module 10 according to the present embodiment, as shown in FIG. 2, it is preferable that the decorative layer 6 is disposed without overlapping the solar cell string 1. That is, it is preferable that the decorative layer 6 is disposed outside the outer peripheral edge of the solar cell string 1. When the decorative layer 6 is disposed in this way, sunlight can be sufficiently irradiated onto the entire solar cell string 1. Thereby, it is possible to suppress a decrease in the power generation amount in the solar cell string 1.

[0018] In the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the first protective plate 2 and the second protective plate 3 have substantially the same dimensions in plan view, and are disposed facing each other so that their outer peripheral edges substantially coincide. In the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the sealing material 4 configured as a sealing layer has substantially the same dimensions as the first protection plate 2 and the second protection plate 3 in a plan view. Also, in the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the water absorption layer 5 also has substantially the same dimensions as the first protection plate 2 and the second protection plate 3 in a plan view. In the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the first protection plate 2 is laminated on one surface of the sealing material 4 configured as a sealing layer, the water absorption layer 5 is laminated on the other surface of the sealing material 4 configured as a sealing layer, and the second protection plate 3 is laminated on the surface of the water absorption layer 5 opposite to the laminated surface of the sealing material 4. That is, in the solar cell module 10 according to the present embodiment, as shown in FIG. 2, the first protection plate 2, the sealing material 4, the water absorption layer 5, and the second protection plate 3 are laminated in this order to form a laminate.

[0019] The solar cell module 10 according to the present embodiment further includes a frame portion 7 that holds the laminate in a state of covering the outer peripheral end portion of the laminate of the first protection plate 2, the sealing material 4, the water absorption layer 5, and the second protection plate 3.

[0020] The solar cell module 10 according to the present embodiment generally has a rectangular shape in a plan view. The solar cell module 10 according to the present embodiment is attached to the roof of a building such as a house or inside the window frame of a building such as a building so that sunlight is irradiated from the first protection plate 2 side. That is, the solar cell module 10 according to the present embodiment is attached to the roof of a building such as a house or inside the window frame of a building such as a building (that is, the wall of the building) so that the first protection plate 2 faces the sunlight irradiation side.

[0021] In the solar cell module 10 according to the present embodiment, the solar cell string 1 includes a plurality of power generation cells 1a that generate power by receiving light. In the solar cell module 10 according to the present embodiment, each of the plurality of power generation cells 1a has an elongated shape, more specifically, an elongated rectangular shape, in a plan view. In the solar cell module 10 according to the present embodiment, each of the plurality of power generation cells 1a is singly connected to each other. That is, in the solar cell module 10 according to the present embodiment, each of the plurality of power generation cells 1a is singly connected to each other to form a solar cell string 1. The single connection means sequentially arranging a plurality of power generation cells 1a having an elongated shape while connecting them so that the long sides of each power generation cell 1a overlap each other. In the solar cell module 10, as shown in FIG. 5, each of the plurality of power generation cells 1a may be connected via wiring (electrical wiring).

[0022] Here, when the solar cell module 10 is installed in a window frame of a building such as a building, passers-by and drivers of vehicles traveling near the building such as a building can visually recognize the inside of the solar cell module 10. That is, passers-by and drivers can visually recognize the solar cell string 1 provided inside the solar cell module 10. Therefore, if the solar cell string 1 exhibits a light color such as white, it is not preferable because it may give a stimulus to the eyes of passers-by and drivers. From such a viewpoint, it is preferable that the solar cell string 1 exhibits a dark color, and among dark colors, it is particularly preferable that it exhibits black. Also, as described above, the solar cell string 1 is configured by connecting a plurality of power generation cells 1a to each other. And a gap may occur at the connection portion between the power generation cells 1a. When a gap occurs at the connection portion between the power generation cells 1a, the passers-by and the driver can visually recognize the water absorption layer 5 disposed between the sealing material 4 and the second protection plate 3 through the gap. In such a case, it is not preferable from the aesthetic point of view that the color tone of the solar cell string 1 is different from the color tone of the water absorption layer 5 disposed between the sealing material 4 and the second protective plate 3. From such a viewpoint, as described above, when the solar cell string 1 exhibits a dark color, it is preferable that the water absorption layer 5 disposed between the sealing material 4 and the second protective plate 3 also exhibits a dark color. Further, the water absorption layer 5 disposed between the sealing material 4 and the second protective plate 3 preferably exhibits a particularly black color among dark colors, similarly to the solar cell string 1.

[0023] The first protective plate 2 is, for example, glass. The thickness of the first protective plate 2 is, for example, 2 mm or more and 8 mm or less.

[0024] The second protective plate 3 is also, similarly to the first protective plate 2, for example, glass. The thickness of the second protective plate 3 is also, similarly to the first protective plate 2, 2 mm or more and 8 mm or less.

[0025] As described above, the sealing material 4 contains a polyolefin elastomer (POE) resin. The polyolefin elastomer (POE) resin exhibits rubber elasticity. Examples of the polyolefin elastomer (POE) resin include a polyethylene-based elastomer resin and a polypropylene-based elastomer resin. Here, the polyethylene-based elastomer resin means an elastomer resin containing 50% by mass or more of ethylene, and the polypropylene-based elastomer resin means an elastomer resin containing 50% by mass or more of propylene. Further, the polyolefin elastomer resin may be a modified polyolefin elastomer resin obtained by copolymerizing a copolymerizable monomer such as an α-olefin, vinyl acetate, or an alkyl (meth) acrylate. Examples of commercially available polyolefin elastomer resins include the ENGAGE 8000 series and 7000 series manufactured by Dow Chemical Company; AFFINITY GA 1900, 1950, 1875, and 1000R manufactured by Dow Chemical Company; Vistamaxx 8380, 8780, 8880, 6102, 6202, 6502, 3000, 3020, 3588FL, and 3980FL manufactured by ExxonMobil; the TAFMER DF series, A series, P series, and XM series manufactured by Mitsui Chemicals; TF4 manufactured by First, and the like. The sealing material 4 may contain a resin other than the polyolefin elastomer resin. The resin other than the polyolefin elastomer resin preferably has appropriate rubber elasticity in the same manner as the polyolefin elastomer resin.

[0026] The sealing of the solar cell string 1 with the sealing material 4 can be carried out by sandwiching the solar cell string 1 from one side (front side) and the other side (back side) with two resin sheets and then pressing these two resin sheets from the outside. That is, the sealing material 4 may be constituted by pressing two resin sheets. Here, in the solar cell module 10 according to the present embodiment, since the sealing material 4 contains a polyolefin elastomer resin, it has sufficient rubber elasticity. That is, when the sealing material 4 is constituted by pressing two resin sheets, since these two resin sheets also contain a polyolefin elastomer resin, these two resin sheets also have sufficient rubber elasticity. Therefore, when the two resin sheets are sandwiched and then these two resin sheets are pressed from the outside to seal the solar cell string 1, the risk of breakage such as cracking in the power generation cell 1a constituting the solar cell string 1 can be reduced, and the risk of breakage at the connection portion of the power generation cell 1a can also be reduced. That is, when encapsulating the solar cell string 1 using the encapsulant 4, the risk of damage to the solar cell string 1 can be reduced.

[0027] As described above, the water absorption layer 5 contains an ionomer resin. The water absorption layer 5 exhibits water absorption by containing an ionomer resin. Therefore, in the solar cell module 10 obtained by pressing the laminate of the first protective plate 2, the encapsulant 4, the water absorption layer 5, and the second protective plate 3 from the first protective plate 2 side and the second protective plate 3 side, even if a slight gap is formed at at least one of the four corners of the first protective plate 2 and the second protective plate 3 and moisture enters the interior through this gap, the water absorption layer 5 can absorb the moisture that has entered.

[0028] Examples of the ionomer resin include thermoplastic resins having structural units derived from olefins such as ethylene and structural units derived from α,β-unsaturated carboxylic acids, with at least a part of the α,β-unsaturated carboxylic acids neutralized by metal ions. Examples of the metal ions include alkali metal ions such as sodium ions; alkaline earth metal ions such as magnesium; zinc ions and the like. In the ethylene-α,β-unsaturated carboxylic acid copolymer before being neutralized by metal ions, the content of the structural unit of the α,β-unsaturated carboxylic acid is preferably 2% by mass or more, more preferably 5% by mass or more, based on the mass of the α,β-unsaturated carboxylic acid. Also, the content of the structural unit of the α,β-unsaturated carboxylic acid is preferably 30% by mass or less, more preferably 20% by mass or less. Examples of the structural unit derived from α,β-unsaturated carboxylic acid that the ionomer resin has include structural units derived from acrylic acid, methacrylic acid, maleic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, etc. Among them, structural units derived from acrylic acid or methacrylic acid are particularly preferred. As the ionomer resin, from the viewpoint of easy availability, an ionomer resin of an ethylene-acrylic acid copolymer and an ionomer resin of an ethylene-methacrylic acid copolymer are more preferable, and a zinc ionomer resin of an ethylene-acrylic acid copolymer, a sodium ionomer resin of an ethylene-acrylic acid copolymer, a zinc ionomer resin of an ethylene-methacrylic acid copolymer, and a sodium ionomer resin of an ethylene-methacrylic acid copolymer are particularly preferable. The ionomer resin may be used alone or in combination of two or more. The water absorption layer 5 may contain a resin other than the ionomer resin. The resin other than the ionomer resin preferably has water absorption properties similar to those of the ionomer resin.

[0029] The decorative layer 6 is provided, for example, to improve the aesthetic appearance of the solar cell module 10 by hiding wiring (electrical wiring) arranged around the solar cell string 1. The wiring is arranged, for example, to take out electrical energy converted from solar energy by the solar cell string 1 to the outside.

[0030] In the solar cell module 10 according to the present embodiment, the decorative layer 6 is a coating film formed on the surface opposite to the light incident surface of the first protective plate 2. The coating film can be formed by applying a resin composition to the surface opposite to the light incident surface of the first protective plate 2 and drying it. Thus, since the decorative layer 6 is formed on the surface opposite to the light incident surface of the first protective plate 2, it is easier to suppress the peeling of the coating film over time compared to the case where the decorative layer 6 is formed on the light incident surface of the first protective plate 2. When the decorative layer 6 is a coating film, the thickness of the coating film is preferably 5 μm or more and 50 μm or less. The coating film can be formed, for example, by ceramic printing.

[0031] The decorative layer 6 blocks (shields) part of the incident light that has passed through the first protective plate 2, or transmits a certain amount of the incident light. That is, in the decorative layer 6, part of the incident light that has passed through the first protective plate 2 is blocked, or part of the incident light is dimmed.

[0032] From the perspective of hiding the wiring (electrical wiring) arranged around the solar cell string 1 and making it less conspicuous when viewed from the inside, the decorative layer 6 preferably exhibits a dark color, and more preferably exhibits black among dark colors. Note that the dark color means black, gray, blue, navy blue, etc. Also, gray is a concept including mouse color, and navy blue is a concept including dark navy (navy). Furthermore, blue means a color with a stronger greenish tint than navy blue. By including a pigment that exhibits a dark color in the resin composition for forming the decorative layer 6, the decorative layer 6 will exhibit a dark color. Examples of the pigment that exhibits a dark color include carbon black.

[0033] The decorative layer 6 is, for example, a coating film formed by covering a predetermined range (by solid coating) on the surface opposite to the light incident surface of the first protective plate 2. The decorative layer 6 may be a coating film in which a plurality of light-blocking regions and a plurality of light-transmitting regions are formed adjacent to each other on the surface opposite to the light incident surface of the first protective plate 2, and light dimming in the thickness direction is achieved by the combination of the light-blocking regions and the light-transmitting regions. Specifically, the decorative layer 6 may be a coating film coated in a dot shape, a mesh shape, etc. in a predetermined range on the surface opposite to the light incident surface of the first protective plate 2. The decorative layer 6 may be a light-blocking film of black or other colors that can be bonded to the surface opposite to the light incident surface of the first protective plate 2. Note that the decorative layer 6 may be formed by coloring a region outside the outer peripheral edge of the solar cell string 1 black or the like in the encapsulant 4. For example, when the sealing material 4 is composed of two resin sheets as described above, in the resin sheet arranged on the side of the first protective plate 2 among the two resin sheets, a portion corresponding to the outside of the outer peripheral edge of the solar cell string 1 is colored black. After sandwiching the solar cell string 1 from one side (front side) and the other side (back side) with the resin sheet partially colored black and the resin sheet not colored black, by pressing these two resin sheets from the outside, a decorative layer 6 can be provided outside the outer peripheral edge of the solar cell string 1 in a state where the sealing material 4 is provided.

[0034] Note that the decorative layer 6 is a separate member from the frame portion 7 that holds the laminate in a state of covering the outer peripheral end portion of the laminate of the first protective plate 2, the sealing material 4, the water absorption layer 5, and the second protective plate 3.

[0035] As described above, the frame portion 7 holds the laminate in a state of covering the outer peripheral end portion of the laminate of the first protective plate 2, the sealing material 4, the water absorption layer 5, and the second protective plate 3. The frame portion 7 has a planar dimension slightly larger than that of the first protective plate 2, the sealing material 4, the water absorption layer 5, and the second protective plate 3 in order to cover the outer peripheral end portion of the laminate. That is, the outer peripheral edge of the frame portion 7 is located outside the outer peripheral edges of the first protective plate 2, the sealing material 4, the water absorption layer 5, and the second protective plate 3. Also, the frame portion 7 is configured to be higher than the laminate in order to cover the outer peripheral end portion of the laminate. Furthermore, as shown in FIG. 2, the frame portion 7 includes a fitting portion 7a into which the laminate can be fitted in order to hold the laminate. By configuring the solar cell module 10 in a state where the laminate is held by the frame portion 7, the mechanical strength can be improved as compared with the solar cell module 10 configured in a state where the laminate is not held by the frame portion 7. By holding the laminate by the frame portion 7, it is possible to suppress dimensional variation in the solar cell module 10. That is, the solar cell module 10 can be maintained in a fixed form.

[0036] Next, with reference to FIG. 3, the solar cell module 10 according to the first modification of the present invention will be described. The solar cell module 10 according to the first modification of the present invention is different from the solar cell module 10 according to the embodiment described above in that a water absorption layer 5 is also disposed between the first protective plate 2 and the sealing material 4. With such a configuration, even if moisture enters from the first protective plate 2 side, the moisture can be efficiently absorbed by the water absorption layer 5 disposed on the first protective plate 2 side. Note that the water absorption layer 5 disposed between the first protective plate 2 and the sealing material 4 is preferably transparent and not colored from the viewpoint of suppressing the difficulty of sunlight from entering the solar cell string 1.

[0037] Next, with reference to FIG. 4, the solar cell module 10 according to the second modification of the present invention will be described. The solar cell module 10 according to the second modification of the present invention is different from the solar cell module 10 according to the embodiment described above in that a water absorption layer 5 is not disposed between the second protective plate 3 and the sealing material 4, and the water absorption layer 5 is disposed only between the first protective plate 2 and the sealing material 4. With such a configuration, in particular, moisture entering the inside of the solar cell module 10 from the first protective plate 2 side can be efficiently absorbed. Note that, as described above, also in the solar cell module 10 according to the second modification of the present invention, the water absorption layer 5 disposed between the first protective plate 2 and the sealing material 4 is preferably transparent and not colored.

[0038] Next, with reference to FIG. 5, the solar cell module 10 according to the third modification of the present invention will be described. The solar cell module 10 according to the third modification of the present invention is different from the solar cell module 10 according to the above-described embodiment in that: (1) each of a plurality of power generation cells 1a is connected via a wiring W to form a solar cell string 1; (2) the wiring W extends from one end side of the solar cell string 1, is folded back to the other end side, and then extends outside the solar cell module 10 through the second protective plate 3; (3) an insulating layer (partition wall) IS is disposed between a portion of the wiring W extending from one end side of the solar cell string 1, being folded back to the other end side, and the solar cell string 1; (4) the sealing material 4 is composed of three resin sheets, i.e., a first resin sheet 4a disposed between the first protective plate 2 and the solar cell string 1, a second resin sheet 4b disposed between the solar cell string 1 and the insulating layer IS, and a third resin sheet 4c disposed between the insulating layer IS and a portion of the wiring W extending from one end side of the solar cell string 1, being folded back to the other end side; and (5) the second protective plate 3 is provided with a hole 3a penetrating in the thickness direction in order to extend the wiring W to the outside. As shown in FIG. 5, the wiring W penetrates the second resin sheet 4b and the third resin sheet 4c in the thickness direction from one end side of the solar cell string 1, is then folded back and further extends to the other end side of the solar cell string 1, penetrates the water absorption layer 5 in the thickness direction, and then extends outside the solar cell module 10 through the hole 3a of the second protective plate 3.

[0039] In the solar cell module 10 according to the present embodiment, since it has a portion of the wiring W extending from one end side of the solar cell string 1, being folded back to the other end side, the degree of freedom regarding the location where the hole 3a is formed in the second protective plate 3 increases. As a result, the degree of freedom in selecting a terminal box disposed outside the solar cell module 10 increases. In addition, by increasing the degree of freedom regarding the location where the hole 3a is formed, it is possible to suppress a decrease in the strength of the second protective plate 3 due to the formation of the hole 3a, which may otherwise cause a decrease in the strength of the solar cell module 10. Also, in the solar cell module 10 according to the present embodiment, since the insulating layer IS is disposed between the solar cell string 1 and a portion of the wiring W that extends from one end side of the solar cell string 1 and is folded back to the other end side, sufficient insulation can be ensured within the solar cell module 10. Also, the insulating layer IS can hide a portion of the wiring W that extends from one end side of the solar cell string 1 and is folded back to the other end side. Thereby, the design property can be improved.

[0040] In the solar cell module 10 according to the third modification of the present invention, although the hole 3a for extending the wiring W to the outside is formed in the second protective plate 3, as shown in FIG. 5, since the water absorption layer 5 is provided between the third resin sheet 4c (sealing material 4) and the second protective plate 3, moisture that enters the inside through the hole 3a can be preferably absorbed. Note that the sealing material 4 (the first resin sheet 4a, the second resin sheet 4b, and the third resin sheet 4c) contains a polyolefin elastomer resin having rubber elasticity, and although the water absorption layer 5 is inferior to the rubber elasticity of the polyolefin elastomer, it contains an ionomer resin that exhibits a certain degree of rubber elasticity. Therefore, after the wiring W penetrates through the sealing material 4 and the water absorption layer 5 in the thickness direction, the sealing material 4 and the water absorption layer 5 contract so as to hold the wiring W without any gap. Therefore, even after the wiring W penetrates through the sealing material 4 and the water absorption layer 5 in the thickness direction, no through hole that allows moisture to enter the inside is formed in the sealing material 4 and the water absorption layer 5.

[0041] The matters disclosed by this specification include the following.

[0042] (1) A solar cell string, A first protective plate having translucency, which is overlapped on the light incident surface side of the solar cell string, A second protective plate, which is overlapped on the side opposite to the light incident surface of the solar cell string, To seal the solar cell string, a sealing material disposed between the first protective plate and the second protective plate, and a water absorption layer disposed on at least one of the spaces between the sealing material and the first protective plate and between the sealing material and the second protective plate. The sealing material contains a polyolefin elastomer resin. The water absorption layer contains an ionomer resin. A solar cell module.

[0043] According to such a configuration, while suppressing the intrusion of moisture into the interior, it is possible to reduce the risk of damage to the solar cell string.

[0044] (2) The water absorption layer is disposed between the sealing material and the second protective plate. Between the sealing material and the water absorption layer, wiring for taking out the electrical energy converted from solar energy by the solar cell string to the outside is disposed. In the second protective plate, a hole for extending the wiring to the outside is formed. The solar cell module according to (1) above.

[0045] According to such a configuration, since the water absorption layer is disposed between the sealing material and the second protective plate, even when a hole for extending the wiring to the outside is formed in the second protective plate, it is possible to sufficiently suppress the intrusion of moisture into the interior of the solar cell module through the hole.

[0046] (3) The solar cell string is configured by connecting a plurality of power generation cells that generate electricity upon receiving light to each other, and exhibits a dark color. The water absorption layer disposed between the sealing material and the second protective plate exhibits a dark color. The solar cell module according to (2) above.

[0047] The solar cell string is configured by connecting a plurality of power generation cells that generate electricity upon receiving light to each other. And gaps may occur at the connection points between the power generation cells. However, when both the solar cell string and the water absorption layer exhibit a dark color as described above, even if gaps are present at the connection points between the power generation cells as described above, it is possible to suppress the water absorption layer from being visually recognized through the gaps. In addition, since both the solar cell string and the water absorption layer exhibit a dark color, the risk of irritating the eyes of an observer inside the solar cell module can be reduced.

[0048] Note that the solar cell module according to the present invention is not limited by the above-described embodiment. Also, the solar cell module according to the present invention is not limited by the above-described effects. The solar cell module according to the present invention can be variously modified without departing from the gist of the present invention.

Example

[0049] Next, the present invention will be further described with reference to examples. The following examples are for further explaining the present invention and do not limit the scope of the present invention.

[0050] (Example 1) On a second protective plate, a water absorption layer, a third resin sheet, a partition (insulating layer), a second resin sheet, a solar cell string, a first resin sheet, and a first protective plate were laminated in this order to obtain a first laminate, and the first laminate was pressed from the first protective plate side and the second protective plate side to fabricate a solar cell module according to Example 1. Glass plates were used as the first protective plate and the second protective plate. As the water absorption layer, a resin sheet containing an ionomer resin and carbon black was used. The ionomer resin had a structural unit derived from ethylene and a structural unit derived from an α,β-unsaturated carboxylic acid, and at least a part of the α,β-unsaturated carboxylic acid was neutralized with metal ions, and it was an ionomer resin. Note that the resin sheet containing the ionomer resin exhibited a black color. As the first resin sheet, the second resin sheet, and the third resin sheet, a resin sheet containing TF4 manufactured by Fisrt as a polyolefin elastomer resin was used. As the partition wall (insulating layer), an insulating sheet obtained by laminating a PET film and a fluorine film was used. In addition, the first laminate was pressed at a pressure of 40 kPa for 12 minutes. Note that the first protective plate and the second protective plate had a planar dimension of 907 mm × 551 mm and a thickness of 2.5 mm, and the first resin sheet, the second resin sheet, the third resin sheet, and the water absorption layer had a planar dimension of 907 mm × 551 mm and a thickness of 0.5 mm. In addition, the solar cell string had a planar dimension of 706 mm × 485 mm and a thickness of 0.2 mm. Furthermore, the partition wall had a planar dimension of 490 mm × 90 mm and a thickness of 0.1 mm.

[0051] (Example 2) A solar cell module according to Example 2 was manufactured in the same manner as in Example 1, except that a water absorption layer, a partition wall (insulating layer), a second resin sheet, a solar cell string, a first resin sheet, and a first protective plate were laminated on the second protective plate in this order to obtain a second laminate.

[0052] (Example 3) A solar cell module according to Example 3 was manufactured in the same manner as in Example 1, except that the pressing conditions of the first laminate were changed to a pressure of 80 kPa for 20 minutes.

[0053] (Comparative Example 1) A solar cell module according to Comparative Example 1 was manufactured in the same manner as in Example 2, except that a partition wall (insulating layer) and a water absorption layer were not used. That is, the solar cell module according to Comparative Example 1 had a laminate in which a second resin sheet, a solar cell string, a first resin sheet, and a first protective plate were laminated in this order on the second protective plate.

[0054] (Comparative Example 2) A solar cell module according to Comparative Example 2 was produced in the same manner as in Example 3, except that a partition wall (insulating layer) and a water absorption layer were not used. That is, the solar cell module according to Comparative Example 2 had a laminate in which a third resin sheet, a second resin sheet, a solar cell string, a first resin sheet, and a first protective plate were laminated in this order on the second protective plate.

[0055] [Water content] [Solar cell module according to Example 1] The solar cell module according to Example 1 was left in an environment of 85% relative humidity and 85°C for 3000 hours, and then the solar cell module according to Example 1 was disassembled. Then, the water content of the first resin sheet and the water absorption layer was measured. The water content of the first resin sheet and the water absorption layer was measured for test pieces cut out from near the corners and near the center of the first resin sheet and the water absorption layer, using a Karl Fischer moisture meter (equipped with a micro moisture measuring device CA-200 type (manufactured by Nitto Seiko Ena Tech Co., Ltd.) as a moisture measuring device and a moisture vaporizing device VA-200 type (manufactured by Nitto Seiko Ena Tech Co., Ltd.) as a vaporizing device). Specifically, after test pieces were cut out from near the corners and near the center of the first resin sheet and the water absorption layer, respectively, a moisture measurement sample was collected from each test piece, and the water content of the moisture measurement sample was measured using a Karl Fischer moisture meter. For near the corners, test pieces were cut out in a rectangular shape so as to have a planar dimension of 20 mm × 15 mm from the first resin sheet and the water absorption layer. For near the center, test pieces were cut out in a square shape so as to have a planar dimension of 15 mm × 15 mm from the first resin sheet and the water absorption layer. The measurement of the moisture content using a Karl Fischer moisture meter was carried out by collecting 0.1 - 0.4 g of test samples for moisture measurement from the test pieces cut out from the first resin sheet and the test pieces cut out from the water absorption layer, respectively, and performing the measurement under the following conditions. · Sample heating temperature: 150 °C · N 2 Flow rate: 300 mL / min · Anolyte: Aquamicron AX (manufactured by Mitsubishi Chemical Corporation) · Catholyte: Aquamicron CXU (manufactured by Mitsubishi Chemical Corporation) Also, the measurement of the moisture content using a Karl Fischer moisture meter was carried out for the test samples collected from any 5 locations for each test piece, and the arithmetic mean of these values was taken as the moisture content for each test piece. The moisture contents near the corners and near the center of the first resin sheet and the moisture contents near the corners and near the center of the water absorption layer are shown in Table 1 below.

[0056] <Solar cell modules according to Examples 2 and 3> The moisture contents of the first resin sheet and the water absorption layer of the solar cell modules according to Examples 2 and 3 were measured in the same manner as in Example 1, except that they were installed in an environment of 85% relative humidity and 85 °C for 6720 hours. The results are shown in Table 1 below.

[0057] <Solar cell modules according to Comparative Examples 1 and 2> The moisture contents of the first resin sheet and the water absorption layer of the solar cell modules according to Comparative Examples 1 and 2 were measured in the same manner as in Example 1, except that they were left in an environment of 85% relative humidity and 85 °C for 6000 hours. The results are shown in Table 1 below.

[0058]

Table 1

[0059] From Table 1, it can be seen that in the solar cell modules according to Examples 1 to 3 having a water absorption layer, the moisture content near the corners of the first resin sheet is at most 240 μg / g, and the moisture content near the central part of the first resin sheet is at most 92 μg / g. Also, in the solar cell modules according to Examples 1 to 3, it can be seen that the moisture content near the corners of the water absorption layer is 1100 μg / g or more, and the moisture content near the central part of the water absorption layer is 510 μg / g or more. On the other hand, in the solar cell modules according to Comparative Examples 1 and 2 having no water absorption layer, it can be seen that the moisture content near the corners of the first resin sheet is at least 455 μg / g, and the moisture content at the central part of the first resin sheet is at least 121 μg. From this result, in the solar cell modules according to Examples 1 to 3, the water absorption layer can sufficiently absorb the moisture that has penetrated into the interior from the slight gaps generated near the corners of the solar cell module, so the moisture content near the corners and the central part of the first resin sheet is sufficiently low. In contrast, since the solar cell modules according to Comparative Examples 1 and 2 do not have a water absorption layer, they cannot absorb the moisture that has penetrated into the interior from the slight gaps generated near the corners of the solar cell module, and it can be seen that the moisture content near the corners and the central part of the first resin sheet is extremely high.

[0060] Also, FIG. 6A shows a photograph of the vicinity of the corner of the solar cell module according to Example 2 immediately before disassembly taken from the side of the first protective plate (the side where sunlight is incident), FIG. 6B shows a photograph of the vicinity of the corner of the solar cell module according to Example 2 immediately before disassembly taken from the side of the second protective plate, FIG. 7A shows a photograph of the vicinity of the corner of the solar cell module according to Example 3 immediately before disassembly taken from the side of the first protective plate, and FIG. 7B shows a photograph of the vicinity of the corner of the solar cell module according to Example 3 immediately before disassembly taken from the side of the second protective plate. However, in any of the photographs, no state where a part of the first protective plate and a part of the second protective plate are peeled off was confirmed. In contrast, FIG. 8A shows a photograph of the vicinity of the corner of the solar cell module according to Comparative Example 1 taken from the first protective plate side immediately before disassembly, and FIG. 8B shows a photograph of the vicinity of the corner of the solar cell module according to Comparative Example 1 taken from the second protective plate side immediately before disassembly. FIG. 9A shows a photograph of the vicinity of the corner of the solar cell module according to Comparative Example 2 taken from the first protective plate side immediately before disassembly, and FIG. 9B shows a photograph of the solar cell module according to Comparative Example 2 taken from the second protective plate side immediately before disassembly. In any of the photographs, a whitening phenomenon was confirmed, which was caused by the peeling of a part of the first protective plate and a part of the second protective plate. This is presumably because, in the solar cell modules according to Comparative Examples 1 and 2, moisture that penetrates from the vicinity of the corners into the interior is not absorbed by the water absorption layer, and thus the adhesion of the first protective plate and the second protective plate to the resin sheet containing the polyolefin elastomer is reduced due to the moisture that has penetrated into the interior.

[0061] [Breakage of solar cell string] After manufacturing the solar cell modules according to Examples 1 to 3 and the solar cell modules according to Comparative Examples 1 and 2, when the interiors of the solar cell modules according to each example were visually observed, no breakage of the solar cell string was confirmed for any of the solar cell modules. This is presumably because, in any of the examples, the solar cell string was sandwiched and sealed between two sheets containing a polyolefin elastomer resin. From this, it can be seen that including a polyolefin elastomer resin in the sealing layer can reduce the risk of breakage of the solar cell string.

Explanation of reference numerals

[0062] 1 Solar cell string, 2 First protective plate, 3 Second protective plate, 4 Sealing material, 5 Water absorption layer, 6 Decorative layer, 7 Frame portion, 10 Solar cell module, 7a Insertion portion, IS Insulation layer (partition wall), W Wiring.

Claims

1. A solar cell string, a first protective plate having translucency, which is superposed on the light incident surface side of the solar cell string, a second protective plate which is glass superposed on the side opposite to the light incident surface of the solar cell string, a sealing material disposed between the first protective plate and the second protective plate to seal the solar cell string, a water absorption layer disposed between the sealing material and the second protective plate, and wiring for taking out to the outside the electrical energy converted from solar energy by the solar cell string, and comprising: the sealing material contains a polyolefin elastomer resin, the water absorption layer contains an ionomer resin, the wiring is disposed so as to extend from one end side of the solar cell string and turn back to the other end side between the sealing material and the water absorption layer, a hole for extending the wiring to the outside is formed in the second protective plate, a solar cell module.

2. the solar cell string is configured by connecting a plurality of power generation cells that generate power upon receiving light to each other, and exhibits a dark color, the water absorption layer disposed between the sealing material and the second protective plate exhibits a dark color the solar cell module according to Claim 1.

Images