JP2010287688A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module increasing the amount of light with which a solar cell light receiving surface is irradiated to increase the power generation efficiency. <P>SOLUTION: The solar cell module 20 includes a resin sealing layer (a light receiving surface side sealing material 2, a solar cell array 7, and a rear surface side sealing material 5) in which a plurality of solar cell modules 3 arrayed in lines are sealed with a transparent resin, a translucent substrate 1 laminated on the light receiving surface side of the resin sealing layer, a back sheet 6 laminated on the rear surface side of the resin sealing layer, and a reflecting material (a strip-shaped light reflecting sheet 10) disposed on the back sheet 6 in a gap between the adjacent solar cells 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solar battery module, and more particularly to a structure that increases power generation efficiency by effectively using light incident on a gap between a solar battery cell and a solar battery cell.

  Polycrystalline silicon solar cells are generally made with a thickness of 0.16 mm to 0.3 mm and are vulnerable to physical impact. Therefore, in order to buffer a physical impact on the solar battery cell, the stacked structure has a structure in which the upper and lower solar battery cells are filled with a sealing material. Usually, a light receiving surface side sealing material having a thickness of 0.6 mm to 1.0 mm is provided on the light receiving surface side of the solar battery cell, and a back surface side sealing material having a thickness of 0.4 mm to 1.0 mm is provided on the back surface side. A back sheet is further provided on the back side of the back side sealing material in order to maintain insulation. Glass is further provided on the light receiving surface side of the light receiving surface side sealing material.

  The gap between a plurality of solar cells and the solar cells provided side by side generally has a width of 2 mm to 4 mm. The light irradiated to other than the light receiving surface of the solar battery cell passes through this gap, is reflected by the back sheet, hits the glass, is reflected again, and is applied to the solar battery cell. This light also contributes to power generation.

  Since the distance in the height direction from the back sheet to the solar cell light-receiving surface side is the total thickness of the back surface side sealing material and the solar battery cell, the distance is 0.56 mm to 1.16 mm. Therefore, the light that is diffusely reflected at a shallow angle among the light reflected by the back sheet hits the back side or the side surface of the solar battery cell and does not contribute to power generation.

  Since the entire back surface side of the solar battery cell is covered with aluminum in order to increase the power generation efficiency, even if light hits the back surface side, it does not contribute to the power generation of the solar battery cell. Further, the side surface has an antireflection structure like the light receiving surface, and since the amount that can be captured even when irradiated with light is small, this also does not contribute much to the power generation of the solar battery cell.

  On the other hand, conventionally, in order to effectively use the light incident on the gap between the solar battery cell and the solar battery cell, a proposal has been made that the back surface portion of the sealing material on the back surface side of the solar battery cell has an uneven shape ( Patent Document 1).

JP 2002-43600 A

  According to the said proposal, light is reflected as the unevenness | corrugation used as the N-type with a continuous cross section on the back surface side of a transparent resin material (sealing material), and the light taken in into a photovoltaic cell is increased. However, in this proposed technique, as well as the conventional technique, since the light hits the back side and the side surface of the solar battery cell, there is light that does not contribute to power generation among the light reflected by the unevenness, which is not sufficient for improving the power generation efficiency. There wasn't.

  This invention is made in order to solve the said subject, By eliminating the light which hits the back surface side and side surface of a photovoltaic cell among the lights irradiated to the clearance gap between a photovoltaic cell and a photovoltaic cell. It aims at providing the solar cell module which can increase the quantity of the light irradiated to a photovoltaic cell light-receiving surface, and can improve electric power generation efficiency by this.

  In order to solve the above-described problems and achieve the object, a solar cell module of the present invention includes a resin sealing layer in which a plurality of solar cells arranged in a row are sealed with a transparent resin, a resin seal A translucent substrate laminated on the light-receiving surface side of the stop layer, a back sheet laminated on the back surface side of the resin sealing layer, and a reflection disposed on the back sheet in the gap between adjacent solar cells. Material.

  Further, in another solar cell module of the present invention, a plurality of solar cells arranged in a row are laminated on a light-receiving surface side of a resin sealing layer in which a resin is sealed with a transparent resin. A translucent substrate and a back sheet laminated on the back side of the resin sealing layer, and the back sheet is formed such that a portion facing a gap between adjacent solar cells rises to the light receiving surface side. It is characterized by being.

  According to the solar cell module of the present invention, the reflective material is disposed on the back sheet in the gap between the solar cells and the solar cells, so that the reflection surface formed in the gap between the solar cells and the solar cells. The height can be increased, and the distance in the height direction from the reflecting surface to the solar cell light receiving surface can be shortened, so that the gap between the solar cell and the solar cell is irradiated and reflected again to the light receiving surface side. Of the light, light that hits the back side or side surface of the solar battery cell can be reduced. Thereby, the quantity of the light irradiated to a photovoltaic cell light-receiving surface can be increased, and electric power generation efficiency can be improved.

  According to another solar cell module of the present invention, the back sheet is formed so that the portion facing the gap between the adjacent solar cells is raised on the light receiving surface side, so that the back sheet of the raised portion forms the reflection surface Then, the height of the reflective surface formed in the gap between the solar battery cell and the solar battery cell can be increased, and the height direction distance from the reflective surface to the solar cell light receiving surface can be shortened, Of the light that is irradiated to the gap between the solar battery cell and the solar battery cell and is reflected again to the light receiving surface side, the light that hits the back surface side or the side surface of the solar battery cell can be reduced. Thereby, the quantity of the light irradiated to a photovoltaic cell light-receiving surface can be increased, and electric power generation efficiency can be improved.

FIG. 1 is a perspective view of the main part (laminated body) of the solar cell module according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of a main part of the solar cell module of FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where there is an output lead corresponding to FIG. FIG. 6 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where there is no output lead corresponding to FIG. FIG. 7 is a cross-sectional view of a portion corresponding to FIG. 3 of a conventional solar cell module shown for comparison. FIG. 8 is a cross-sectional view of a portion corresponding to FIG. 4 of a conventional solar cell module shown for comparison. FIG. 9 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where there is an output lead wire of a conventional solar cell module corresponding to FIG. FIG. 10 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where there is no output lead wire of a conventional solar cell module corresponding to FIG. FIG. 11 is an exploded perspective view of essential parts of the solar cell module according to Embodiment 2 of the present invention. FIG. 12 is a cross-sectional view of a portion corresponding to FIG. 3 showing another example of the solar cell module according to the present invention. FIG. 13 is a cross-sectional view of a portion corresponding to FIG. 4 showing another example of the solar cell module according to the present invention.

  Embodiments of a solar cell module according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a perspective view of the main part (laminated body) of the solar cell module according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of a main part of the solar cell module of FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a cross-sectional view taken along line BB in FIG.

  1 and 2, the laminated body constituting the main part of the solar cell module 20 includes a light-transmitting substrate 1 made of a transparent material such as glass and a light-receiving surface-side sealing material made of a transparent resin from the light-receiving surface side. (First resin layer) 2, a plurality of solar cells 3 arranged in a grid pattern, and a solar cell array 7 wired with output lead wires 4 connecting the plurality of solar cells 3 in series or in parallel. And a back surface side sealing material (second resin layer) 5 made of a transparent resin, and a grid like a shoji bar, and each solar cell 3 is accommodated in each opening, A strip-shaped light-reflective sheet 10 that surrounds the periphery of the solar battery cell 3 one by one over the entire circumference and works as a reflector, and a back sheet 6 that is excellent in weather resistance are laminated in this order. The light-receiving surface side sealing material 2 and the back surface side sealing material 5 are integrated by heat treatment, and the solar cell array 7 is resin-sealed to form a resin sealing layer. The solar cell module 20 is manufactured by covering the outer peripheral edge of the laminated body having such a configuration with a frame frame (not shown) over the entire circumference.

  For the translucent substrate 1, a synthetic resin material such as a glass material or a polycarbonate resin is used. Further, as the glass material, white plate glass, tempered glass, heat ray reflective glass or the like is used, and generally white plate tempered glass having a thickness of about 3 mm to 4 mm is often used. On the other hand, a polycarbonate resin having a thickness of about 5 mm is often used.

  The light-receiving surface side sealing material 2 is made of a material having translucency, heat resistance, electrical insulation and flexibility, and thermoplastics mainly composed of ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or the like. The synthetic resin material is preferable. As the thickness, a sheet form having a thickness of about 0.6 mm to 1.0 mm is used.

  The solar battery cell 3 is made of a single crystal silicon or a polycrystalline silicon substrate having a thickness of about 0.16 mm to 0.3 mm. A PN junction is formed inside the solar battery cell 3, electrodes are provided on the light receiving surface and the back surface, and an antireflection film is provided on the light receiving surface. As for the size of the solar battery cell 3, the length of one side in the polycrystalline silicon solar battery is about 150 mm to 156 mm.

  The output lead wire 4 is made of a rectangular copper wire having a solder plating thickness of about 0.1 mm to 0.4 mm. The output lead wire 4 is joined to the solar cell 3 by soldering, and electrically connects the back surface side electrode and the light receiving surface side electrode of each solar cell 3.

  The back surface side sealing material 5 is made of a material having translucency, heat resistance, electrical insulation and flexibility, like the light receiving surface side sealing material 2, and is made of ethylene vinyl acetate (EVA) or polyvinyl butyral (PVB). A thermoplastic synthetic resin material containing as a main component is suitable. The thickness is about 0.4 mm to 1.0 mm.

  The light-receiving surface side sealing material 2 and the back surface side sealing material 5 are thermally cross-linked in a laminating step under a reduced pressure of about 0.5 atm to 1.0 atm, so that the translucent substrate 1, the solar cell array 7, and the back sheet. 6 and unite by fusing.

  The back sheet 6 is made of a material excellent in moisture permeability, weather resistance, hydrolysis resistance, and insulation, and a fluorine resin sheet, a polyethylene terephthalate (PET) sheet deposited with alumina or silica, or the like is used.

  The strip-like light-reflective sheet 10 has a lattice shape like a shoji frame as a whole, and a lattice between a long strip-like vertical frame 10a extending in the connecting direction of the solar cells 3 and the adjacent vertical frames 10a. It is comprised from the short strip-shaped horizontal frame 10b arrange | positioned orthogonally to the connection direction of the photovoltaic cell 3 so that it may connect with a shape. The thickness of the vertical frame 10a (the height on the back sheet 6) is the same as the height distance from the upper surface of the back sheet 6 to the light receiving surface of the solar battery cell 3 (FIG. 4). On the other hand, the thickness of the horizontal frame 10b (height on the back sheet 6) is such that there is the output lead wire 4, so that no stress is applied to the output lead wire 4 from the upper surface of the back sheet 6. The height distance to the back surface is the same (FIG. 3).

  In the strip-shaped light reflective sheet 10 of the present embodiment, the vertical frame 10a and the horizontal frame 10b are each formed by cutting out a sheet used as the back sheet 6 into a long and narrow strip shape and stacking a predetermined number thereof.

  In the portion where there is no output lead 4, the light reflected by the strip-shaped light reflective sheet 10 does not hit the back surface side and the side surface of the solar battery cell 3, but the amount of light applied to the light receiving surface of the solar battery cell 3 increases. In the portion where the output lead wire 4 is present, the light reflected by the strip-shaped light reflective sheet 10 is incident on the side surface of the solar battery cell 3, so that the amount of light irradiated on the light receiving surface of the solar battery cell 3 is the former. Decrease a little more.

  The back sheet 6 is required to use an insulating material in order to maintain the insulation of the solar cell module 20, but the strip-like light reflective sheet 10 does not need to be an insulating material, and therefore the same sheet material as the back sheet 6. Not necessarily. Therefore, the power generation efficiency of the solar battery cell 3 can be improved by using a sheet having a surface having a light reflectance higher than that of the back sheet 6. For example, PET or PVF is generally used as a material for the back sheet 6, but a sheet containing a large amount of magnesium carbonate (diffuse reflectance 98%) or barium sulfate (diffuse reflectance 93%) is not used. May be used. Of course, you may use what cut out the back seat | sheet 6. FIG.

  Moreover, as a material of the strip-shaped light reflective sheet | seat 10, the electric power generation efficiency of the photovoltaic cell 3 shall reflect a lot of light of the optimal wavelength range (500 nm-1000 nm) with respect to the quantum efficiency of the photovoltaic cell 3. Can be increased. For example, the light reflectance can be increased by using white that has little light absorption in the entire wavelength region.

  Furthermore, the surface state of the strip-shaped light-reflective sheet 10 is made to be irregularly reflected by corrugated discharge treatment or the like so that the reflected light is irregularly reflected. This is because if the reflected light is regularly reflected, it is not totally reflected by the translucent substrate 1 and thus does not contribute to the solar battery cell 3. The irregular reflection angle of the reflected light due to the unevenness is preferably within 42 ° with respect to the translucent substrate 1. This is because when the translucent substrate 1 is glass, the refractive index is generally 1.52, and therefore the angle of total reflection with the air layer is within 42 °.

  FIG. 5 is a cross-sectional view showing a path of light irradiated between the solar cells in a portion where the output lead wire 4 is present corresponding to FIG. FIG. 6 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where there is no output lead 4 corresponding to FIG. FIG. 7 is a cross-sectional view of a portion corresponding to FIG. 3 of a conventional solar cell module shown for comparison. FIG. 8 is a cross-sectional view of a portion corresponding to FIG. 4 of a conventional solar cell module shown for comparison. FIG. 9 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where the output lead wire 4 of the conventional solar battery module is provided, corresponding to FIG. FIG. 10 is a cross-sectional view showing a path of light irradiated between solar cells in a portion where the output lead wire 4 of the conventional solar battery module is absent, corresponding to FIG. 5 and 6, the structure is the same as in FIGS. 9 and 10, the structure is the same as that in FIGS.

  7 to 10, the conventional solar cell module is not provided with the strip-like light reflective sheet 10. Other configurations are the same as those of the present embodiment. 5, 6, 9, and 10, an arrow a indicates a path of light applied to the solar cell module, and an arrow b indicates the light reflected from the strip-shaped light reflective sheet 10 or the back sheet 6 at a deep angle. The path c indicates the path of light reflected at a shallow angle on the strip-shaped light reflective sheet 10 or the back sheet 6.

  As is clear by comparing FIGS. 5 and 6 with FIGS. 9 and 10, the reflection angle is increased by providing the strip-shaped light reflective sheet 10 and increasing the height of the reflective surface between the solar cells 3. Even if the light is shallow, it will not hit the back side or the side surface of the solar battery cell 3, and the amount of light irradiated to the light receiving surface of the solar battery cell 3 will increase. Thereby, the electric power generation efficiency of the photovoltaic cell 3 can be improved.

  Next, the manufacturing method of this embodiment will be described. First, the rectangular translucent substrate 1 is disposed with the light receiving surface facing downward. A sheet-shaped light-receiving surface side sealing material 2 made of EVA resin is disposed on the back surface of the translucent substrate 1. Furthermore, a solar cell array 7 in which a plurality of solar cells 3 are electrically wired by output lead wires 4 is disposed on the light receiving surface side sealing material 2. At this time, the light receiving surface of the solar battery cell 3 is arranged facing the translucent substrate 1 side. Further, a sheet-like rectangular backside sealing material 5 made of EVA resin is disposed on the solar cell array 7.

  And on the back surface side sealing material 5, the vertical frame 10a and the horizontal frame 10b of the strip-shaped light reflective sheet | seat 10 are arranged in the clearance gap between the photovoltaic cell 3 and the photovoltaic cell 3. FIG. At this time, if the positions of the vertical frame 10a and the horizontal frame 10b are shifted, the solar battery cell 3 may be cracked. Therefore, the vertical frame 10a and the horizontal frame 10b are accurately fixed by fixing with Teflon (registered trademark) tape or the like. Positioning may be performed. Finally, the back sheet 6 is disposed on the strip-like light reflective sheet 10 to complete the production of the laminate.

  The laminate is pressurized at about 0.5 atm to 1.0 atm while being heated by a laminator in a vacuum state at a temperature of 100 ° C to 200 ° C for about 15 minutes to 1 hour. As a result, the light-receiving surface side sealing material 2 and the back surface side sealing material 5 are softened and crosslinked and fused, so that the translucent substrate 1, the solar battery cell 3, the strip-shaped light reflective sheet 10, and the back sheet 6 are formed. It is fused and integrated. Finally, the solar cell module 20 is completed by fitting frame frames (made of a metal material such as aluminum or SUS, or a synthetic resin material) to each side of the outer periphery of the integrated laminate and fixing each corner. To do.

Embodiment 2. FIG.
FIG. 11 is an exploded perspective view of essential parts of the solar cell module according to Embodiment 2 of the present invention. In this Embodiment, it replaces with the strip-shaped light-reflective sheet | seat 10 of Embodiment 1, and replaces with the strip-shaped light-reflective sheet | seat 10 of Embodiment 1 as a grid-like reflecting material like the frame of the shoji which surrounds the circumference | surroundings of each photovoltaic cell 3 over a perimeter. A die-cut reflective sheet 11 is provided. Other configurations are the same as those of the first embodiment. The die-cut reflective sheet 11 has a shape in which the vertical frame 10a and the horizontal frame 10b of the strip-shaped light reflective sheet 10 of Embodiment 1 are integrally connected. The die-cut reflective sheet 11 is manufactured by being integrally formed in a lattice shape by a mold forming process using a mold. Alternatively, the plate member is punched into a lattice shape by press punching. In the present embodiment, the same effects as in the first embodiment can be obtained, and the workability of the manufacturing process can be improved because the die-cut reflective sheet 11 has a single structure.

  In the said Embodiment 1, 2, a photovoltaic cell is reflected from the reflective surface which the light irradiated other than a photovoltaic cell reflects by arrange | positioning a reflecting material on the back sheet of the clearance gap between a photovoltaic cell and a photovoltaic cell. Although the distance in the height direction to the light receiving surface is shortened, the effect of this structure is not only by attaching a reflective material to the back sheet, but also, for example, adjacent to the back sheet 16 as shown in FIGS. The portion facing the gap between the solar cells 3 is formed so as to rise to the height of the back surface of the solar cells 3 and the height of the light receiving surface of the solar cells 3, and from the reflecting surface to the light receiving surface of the solar cells. The height direction distance may be shortened.

  In Embodiments 1 and 2 described above, the use of a crystalline solar cell such as polycrystalline silicon or single crystal silicon has been described, but a non-crystalline solar cell such as a thin film solar cell or an organic solar cell. However, the present invention is applicable.

  The results of actually generating power using the solar cell module to which the present invention is applied and measuring the power generation efficiency are shown below. The measurement was performed by stacking a strip-shaped reflector having a thickness of about 0.12 mm from 0 to 1 on the back sheet. In addition, the examination on the desk was repeated from 0 to 3 sheets.

In the desk study, the improvement of the power generation efficiency of the solar cells was as follows.
When 0 sheets are stacked (no sheet is stacked): 0% improvement (standard)
When one sheet is stacked: 0.14% improved When two sheets are stacked: 0.29% improved When three sheets are stacked: 0.49% improved

On the other hand, in the actual experiment, the power generation efficiency of the solar battery cell was improved as follows.
(1) When 0 sheets are stacked (when no sheets are stacked): 0% improvement (standard)
(2) When one sheet is stacked: 0.19% improvement

  Note that (1) was evaluated with a white backsheet having a reflectance of about 85%. In (2), a sheet used as a back sheet was cut into a strip shape, and was applied as a reflective material in an overlapping manner on the back sheet. When a strip of reflective material is stacked on the back sheet, if the reflective material is white and the back sheet is also white, the total of the white will be twice that of the normal, so the transmittance will be reduced and substantially reflected. The back sheet is transparent, and the strip-shaped reflector is white, so that only the effect when the distance in the height direction between the back sheet and the solar cells is reduced is concerned. Was extracted.

The sheet used as the back sheet was cut into a strip shape and overlapped on the back sheet as a reflective material, whereby the distance from the solar battery cell was as follows.
When 0 sheets are stacked (no sheets are stacked): 0.4 mm (reference)
When one sheet is stacked: 0.28mm
From this example, it was confirmed that the power generation efficiency of the solar cells could be improved by reducing the distance between the back sheet and the solar cells.

  In addition, this time, a sheet used as a back sheet having a thickness of about 0.12 mm and a reflectance of about 85% is cut into a strip shape, and the back sheet is stacked to reduce the distance in the height direction between the back sheet and the solar cells. The power generation efficiency was measured. However, further improvement in power generation efficiency of the solar cell can be expected by using the optimum thickness, reflectance, color, and surface structure. For example, the thickness is 0.6 mm, the light reflectance is 90% by adding a large amount of white content, the corona discharge treatment is performed to make the surface structure uneven, and an angle within 42 ° with respect to the translucent substrate Use a sheet that reflects light.

  As described above, the solar cell module according to the present invention includes a resin sealing layer in which a plurality of solar cells arranged in a row are sealed with a transparent resin, and laminated on the light receiving surface side of the resin sealing layer. The present invention is useful when applied to a solar cell module including the light-transmitting substrate and a back sheet laminated on the back side of the resin sealing layer.

DESCRIPTION OF SYMBOLS 1 Translucent board | substrate 2 Light-receiving surface side sealing material (transparent resin sealing material)
3 Solar cell 4 Output lead 5 Back side sealing material (transparent resin sealing material)
6,16 Back sheet 7 Solar cell array 10 Strip light reflective sheet (reflective material)
11 Die-cut reflective sheet (reflective material)
20 Solar cell module

Claims (11)

A resin sealing layer in which a plurality of solar cells arranged in a row are sealed with a transparent resin;
A translucent substrate laminated on the light-receiving surface side of the resin sealing layer;
A back sheet laminated on the back side of the resin sealing layer;
A solar cell module comprising: a reflector disposed on the back sheet in a gap between adjacent solar cells. The solar cell module according to claim 1, wherein the reflective material surrounds the periphery of the solar cell over the entire circumference. The plurality of solar cells are arranged in a grid pattern in the same plane,
The reflector is formed in a lattice like a shoji bar, and each solar cell is enclosed in each opening so as to surround the entire circumference of each solar cell. 3. The solar cell module according to 1 or 2. The plurality of solar cells are arranged in a grid pattern in the same plane and are electrically connected by output lead wires extending between them,
The reflective material has a first height at a position where the output lead does not exist and a second height lower than the first height at a position where the output lead exists. The solar cell module of any one of Claim 1 to 3. The solar cell module according to any one of claims 1 to 4, wherein the reflective material has a higher reflectance than the back sheet. The solar cell module according to any one of claims 1 to 5, wherein the reflector is manufactured by connecting a plurality of strip-shaped members. The solar cell module according to claim 6, wherein the strip-shaped member is manufactured by stacking a predetermined number of thin plate members. The solar cell module according to any one of claims 1 to 5, wherein the reflector is integrally manufactured by punching or molding. The solar cell module according to any one of claims 1 to 8, wherein the reflecting surface of the reflecting material has an uneven shape that diffusely reflects reflected light. The solar cell module according to any one of claims 1 to 9, wherein the reflective material is white. A resin sealing layer in which a plurality of solar cells arranged in a row are sealed with a transparent resin;
A translucent substrate laminated on the light-receiving surface side of the resin sealing layer;
A back sheet laminated on the back side of the resin sealing layer,
The back sheet is formed so that a portion facing a gap between the adjacent solar cells is raised to the light receiving surface side.

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