JPH10284747A - Solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve solar light power generation conversion efficiency per sheet of solace battery cell at the time of module mounting by setting the cell intervals of a plurality of solar battery cells, in such a manner that the relation between the cell interval and the electric output change ratio of each of the solar battery cells satisfies a specified formula. SOLUTION: Sun light 5 entering through a front cover member 3 which is composed of transmitting material and transparent filer 2 reaches the light- receiving surface of a plurality of solar battery cells 1, which are arranged in a plane at specified intervals Sm and contributes to power generation. Sun light 5 entering the intervals Sm is reflected by a reflecting material, which is contained in a module rear cover member 4 and especially improves scatter refection properties, again reflected by the front surface cover member 3, and reaches each of the light-receiving surfaces of a plurality of the solar battery cells 1. At this time, the relation of Ln(Sm[mm])=A×(Qm[%])+B is satisfied, where Ln is natural logarithm function, Qm is an electric output change ratio, and A and B are constants.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module suitable for use in a residential solar power generation system.

[0002]

2. Description of the Related Art As a conventional example, for example, JIS C 891
According to the solar cell module structural classification system specified in 8 above, the solar cell modules are classified into three types: superstrate type, substrate type, and filling type. Will be described with reference to FIGS. 8, 9 and 10. FIG.

FIG. 8 is a structural diagram of a typical super straight type solar cell module, and FIG. 9 is a diagram showing a cross-sectional structure taken along a plane A in FIG. FIG. 10 is a partially enlarged sectional view of the back cover member 14 shown in FIG. As is apparent from the figure, a plurality of solar cells 11 are electrically connected in series or in parallel to each other by an interconnector 15, and the light receiving surface side of the solar cells 11 is made of a light-transmitting material. The front cover member 13 is placed as a support member for the module, and a transparent filling material 12 and a back cover member 14 are used thereunder to support the plurality of solar cells 11.
Is enclosed.

As the light-transmitting front cover member 13, glass is suitable, and in particular, white-sheet tempered glass excellent in light transmittance and impact resistance is often used. As the transparent filling material 12, PVB (Poly Vinyl Bu-tylol), which has a small decrease in light transmittance due to ultraviolet rays, EVA (Ethylene Vinyl Acetate) having excellent moisture resistance, and the like are mainly used. As shown in a partially enlarged cross section of FIG. 10, a metal film 41 such as aluminum (Al) is formed on the back cover member 14 by PET (Polyethylene Telephth).
alate) and a layered structure sandwiched between weather-resistant resin films 42 and 43 to provide weather resistance and moisture resistance and electrical insulation.

Further, outer frames 16, 17, 18, and 19 made of extruded aluminum (Al), which is a lightweight metal, are attached in order to impart strength to the entire module. Reference numeral 20 denotes a screw for assembling the outer frames 16, 17, 18, and 19.

[0006]

In the conventional solar cell module, a large number of small solar cells 11 are mounted on one large transparent front cover member 13 as shown in FIG.
Although the output power is increased by arranging as described above, in order to increase the amount of power generation per module, the gap between a plurality of arranged solar cells 11 is made as narrow as possible and a large number of solar cells 11 are mounted. Is customary. However, as shown in FIG. 9, the plurality of solar cells 11 electrically connected to each other by the interconnector 15 particularly in series are
In order to electrically insulate the adjacent solar cell 11,
Alternatively, since the interconnector 15 is arranged from the back surface of the cell connected in series to the front surface of the next cell, it is difficult to make the gap as small as negligible. In the conventional solar cell module, the gap is usually about 2 mm to 5 mm. Needed. The light incident on the cell gap does not contribute to the power generation, and the reduction in the power generation efficiency of the solar cell per module-mounted cell due to the light cannot be avoided.

[0007] In order to alleviate the decrease in the power generation efficiency of the solar cell when the module is mounted, the present applicant has
As already disclosed in Japanese Utility Model Application Laid-Open No. 62-101247, the light incident side of the back cover member 14, that is, the front surface side is made to have a scattered reflection property to scatter the sunlight entering the gap. A solar cell module for the purpose of being reflected and reflected by the front cover member 13 to reach the solar cell 11 has also been devised. However, when the gap between the adjacent solar cells 11 is only about 2 mm to 5 mm as described above, the effect was hardly confirmed.

[0008]

According to a first aspect of the present invention, there is provided a solar cell module comprising: a plurality of solar cells arranged in a plane with a cell gap therebetween; A front cover member made of a translucent material commonly arranged on the light receiving surface side, and commonly arranged behind the plurality of solar cells to scatter and reflect light incident from the front through the cell gap. A solar cell module having a back cover member including a reflective material, wherein light incident through the cell gap is reflected by the reflective material, and further reflected again by the front cover member; To reach each light receiving surface of the solar cell, each of the plurality of solar cells can convert light energy incident on each light receiving surface into electrical energy with higher efficiency, and the cell And gap, the relationship between each of the electrical output change rate of the solar cell, so as to satisfy the following expression, is characterized in that sets the plurality of solar cells each other cell gap. Ln (Sm [mm]) = A × (Qm [%]) + B where Ln is a natural logarithmic function, Sm is a cell gap, Qm is an electric output change rate, and A and B are constants.

A solar cell module according to a second aspect of the present invention is a metallic material which has been subjected to a matte surface treatment for improving the scattering property of the reflective material, or a resin material mixed with a white pigment. It is characterized by comprising.

According to a third aspect of the present invention, in the solar cell module, the back cover member is made of a reflective material made of a resin material mixed with the white pigment, and a weather-resistant material made of a dielectric material. Characterized by comprising at least two layers.

The solar cell module according to claim 4 of the present invention is characterized in that at least the surface of the reflective material on which light is incident has an uneven shape.

Further, in the solar cell module according to a fifth aspect of the present invention, the concave and convex shape of the reflective material is a triangular wave shape, a pyramid shape or an inverted pyramid shape.

In the solar cell module according to a sixth aspect of the present invention, a cell gap S between the plurality of solar cells is provided.
m is 5 mm <Sm ≦ 100 mm, preferably 5 m
m <Sm ≦ 30 mm.

Further, the solar cell module according to claim 7 of the present invention is characterized in that the reflective material has a surface reflectance of at least 70% or more.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view for explaining the basic principle of the present invention particularly configured as a super-straight type solar cell module, through a front cover member 3 made of a translucent material such as glass and a transparent filling material 2 made of EVA or the like. The incident sunlight 5 has a predetermined gap Sm.
To reach the light receiving surfaces of the plurality of solar cells 1 arranged in a plane to contribute to power generation, and to provide the gap Sm
Sunlight 5 incident on the plurality of solar cells 1 is also reflected by the reflective material included in the module back cover member 4 and improving the scattering and reflection properties, and further re-reflected by the front cover member 3. And each of the plurality of solar cells can convert light energy incident on each light receiving surface into electric energy with higher efficiency.

FIG. 2 shows a simulated super straight type solar cell module 6 prepared for an experiment for confirming the utility of the present invention, in which an output measuring cell Q is arranged substantially at the center of the module, and eight cells are arranged around the module. And the photovoltaic output of the output measurement cell Q was measured using the gap Sm between the cells as a parameter. For example, the size of the output measurement cell Q is a pseudo-angle cell of about 100 mm square.

FIG. 3 shows the cell gap Sm based on the above experimental results.
Electric output change rate Qm of output measuring cell Q with respect to
Is a graph of the relationship data of FIG. For example, data of the cell gap Sm and the electric output change rate Qm are 2 mm,
For the cell gaps Sm of 4 mm, 8 mm, 16 mm, and 32 mm, the electric output change rates Qm are 1% and 3.5, respectively.
%, 5.2%, 7.2%, 8.8%, and the characteristic curve of the electric output change rate Qm with respect to the cell gap Sm is exponential. If the cell gap Sm is 5 mm or less, the value of the electric output change rate Qm [%] itself is still small, and if the cell gap exceeds 30 mm, the rate of increase in the electric output change rate Qm becomes small and tends to be saturated. . Therefore, it is practical that the cell gap Sm is larger than 5 mm and about 30 mm. Since the experiment was performed using a 100 mm square solar cell, the cell gap was 100 mm.
Setting a larger value is meaningless.

FIG. 4 is a logarithmic graph of the characteristic curve of FIG. 3. According to the graph, the following relational expression is established between the cell gap Sm [mm] and the electric output change rate Qm [%]. I understand. Ln (Sm [mm]) = A × (Qm [%]) + B Here, Ln is a natural logarithmic function, Sm is a cell gap, Qm is an electric output change rate, and A and B are constants. The constant A is
A constant determined by the reflectance of the reflective member placed on the back side of each solar cell and the distance from the front cover member, etc., a constant B is
It is a constant determined by the area of one solar cell and the conversion efficiency of the photovoltaic power generation. In the above experimental results, A = 0.36
4, B = 0.215. In this case, the reflectance of the reflective member placed on the back side of each solar cell is about 70%.
%, And the size of one solar cell is 100 mm □
Thus, a single crystal cell having a solar power generation conversion efficiency of 17% was used.

In the above-described experimental example of the solar cell module according to the embodiment of the present invention, the module back cover member including the reflective member has the same structure as the conventional structure shown in FIG. A white pigment such as silica (SiO ₂ ) is mixed into the resin film 42 on the upper surface side of the central aluminum material 41, that is, on the sunlight incident side, to have a scattering reflection property, or EVA shown in FIG.
The white pigment is mixed into the upper and lower two layers of the filling material 12 to fill the lower side thereof, that is, the layer filling the back side of the solar cell 11 (the output measurement cell Q and the dummy cell D in FIG. 2). (Not shown), and the reflectivity of the scattering reflective member was set to about 70%. However, if this reflectivity is increased to 80% or 90%, another experiment can be performed to further improve the electric output. I understood.

FIG. 5 shows a structure that can further increase the reflectance of the scattering reflective member included in the back cover member.
The back cover member 7 has at least a surface on which light is incident or an entire surface thereof having an uneven shape. The uneven shape has a triangular wave shape, a pyramid shape, or an inverted pyramid shape. With such a shape, almost the entire amount of the light 5 incident from the front surface is multiple-reflected as shown by the traveling direction arrow 5a, returns to the front surface, is reflected again by the front cover member 3, and reaches the solar cell 1 again. , Can contribute to the improvement of the electric output. Although not shown in FIG. 5, it goes without saying that a filler material 2 such as a transparent resin film 42 or a transparent EVA is provided above the aluminum material 41. In addition, with such an uneven shape, the surface of the aluminum material 41 may remain mirror-finished (glossy) without being subjected to a matte surface processing for improving the scattering reflectivity.

By the way, in the case of a super straight type solar cell module, the back cover member 4 is usually formed in a thin film form because of the necessity of reducing its weight. When the back cover member 7 has such an uneven shape, the inner aluminum material 41 is more likely to be exposed, and it is conceivable that electrical insulation breakdown accidents as a module may occur more frequently.

Therefore, in consideration of electric insulation, a resin film in which the back cover member 7 does not use a conductive metal material such as an aluminum material but instead contains a white pigment such as silica (SiO ₂ ). And the back cover member 7 is composed of at least two layers of
A film in which a dielectric film such as an inorganic oxide (for example, SiO _x ) or a nitride (for example, SiN _x ) having a better moisture-proof function is additionally inserted between the layers by vapor deposition or the like is used as the back cover member 7. The replacement is also a feature of the embodiment of the present invention. If this is shown in FIG. 5, 41 is silica (Si
O ₂ ) is replaced with a resin film in which a white pigment such as O ₂ ) is mixed.
The back cover member 7 has a structure (not shown) in which a dielectric film having a good moisture-proof function is additionally inserted by a method such as vapor deposition.

The embodiment of the present invention has been described above with reference to FIGS. 1 to 5. However, this is an ideal embodiment confirmed by experiments. As can be seen from FIG. 3, the larger the gap Sm between the respective solar cells is set to be larger than 5 mm and about 30 mm, the larger the area of the module must be. However, as a practical matter, when several to several tens of solar cell modules are installed as a unit as a solar power generation system for a house, the installation area is often limited.

Therefore, the embodiment of the present invention is applied to a module having the same dimensions as that of the conventional one, which is a module shown in FIG. The efficiency is about 17%. Comparing the module of this figure with the conventional module shown in FIG. 8, in the module of FIG. 8, 54 solar cells 11 are arranged in 6 columns × 9 rows, and the gap between the cells is The distance between columns is about 2 mm, and the size of the light receiving side of the solar cell module is about 614 mm × about 920 mm.
= About 5648.8 cm ² . In the module according to the embodiment of the present invention shown in FIG. 6, the same solar cells as those in FIG. 8 are arranged in 6 columns × 8 rows = 48 sheets. 2mm, line spacing about 20m
m, the distance between the surrounding cells and the frame is about 2 mm, and the size of the light receiving side of the solar cell module is about 614 mm ×
About 944 mm = about 5796.2 cm ² . FIG. 7 is a partially enlarged cross-sectional view taken along the line AA ′ of FIG. 6, and FIG. 9 is a partially enlarged cross-sectional view taken along the line BB ′ of FIG.
Is the same as that of the conventional example.

Here, FIG. 6 of the module according to the present invention shows that although the number of cells is reduced by 6, the absolute value of the photovoltaic power output as a module is small.
It was confirmed that the electric output change rate Qm was improved by about 4%. In other words, FIG.
This means that the relative output is improved while reducing the number of solar cells as compared with the conventional module shown in FIG. When the electric output change rate Qm is improved by about 4% when converted into the basic form of the present invention in FIG. 2, as can be seen from the characteristic graph in FIG. ６6 mm.

Although the module output of the module according to the present invention shown in FIG. 6 is 126 W, it is assumed that a slight increase in the module size is allowed, and that 54 solar cells can be mounted similarly to the conventional module. Then, the module output becomes 141.4W. However, in the conventional module shown in FIG. 8, the module output is 136 despite the fact that 54 solar cells are mounted.
W. In other words, FIG.
The output per solar cell of the conventional module has been improved from 2.52 W in FIG. 8 to 2.62 W in the conventional module.

When a residential photovoltaic power generation system is constructed using the module according to the present invention having the above-mentioned characteristics and FIG. 6, for example, when 24 modules are used, the total output of the system is 126 W × 24 °. 3.02kW
, Which is sufficient for a nominal output 3 kW system. However, if the number of solar cells mounted is set to 48 while keeping the concept of the conventional module of FIG. 8, only 121 W of module output can be taken out, and the system output of 12 W
1W × 24 ≒ 2.90 kW, which was not compatible with a nominal output 3 kW system. (Conventionally, the solar cell 54
136W × 24 system output as a single module
に し て 3.26 kW, corresponding to a nominal output 3 kW system. In other words, in FIG. 6 of the module to which the present invention is applied, the number of solar cells mounted is reduced from 54 to 48 from the conventional module of FIG. That is, at present, the cost (cost) of the solar cell with respect to the manufacturing cost of the module accounts for 70% or more, and the cost reduction effect by saving six solar cells is ((54/48) -1). × 0.7 = 8.7
Up to 5%. This cost reduction effect is extremely important in promoting the spread of residential photovoltaic power generation systems. The high-purity silicon required for the manufacture of solar cells and semiconductor integrated circuits cannot be purified without special techniques and equipment, and the solar cell module to which the present invention is applied is a high-purity silicon raw material. Will contribute to solving the tightness problem. Incidentally, the present invention,
Although a description has been given of a typical superstrate type solar cell module, it is needless to say that the present invention can be applied to other substrate type and filling type solar cell modules defined in JIS C 8918, or other types of modules.

[0028]

According to the solar cell module of the first aspect of the present invention, a plurality of solar cells arranged in a plane with a cell gap therebetween, and each light receiving surface of the plurality of solar cells. A front cover member made of a translucent material commonly disposed on the side, and a reflective member commonly disposed behind the plurality of solar cells and scattering and reflecting light incident from the front through the cell gap. A back cover member including a material, wherein the light incident through the cell gap is reflected by the reflective material, further reflected again by the front cover member, the plurality of solar cells Reaching each light receiving surface of the battery cell, each of the plurality of solar cells is capable of converting light energy incident on each light receiving surface to electrical energy with higher efficiency, and
The relationship between the cell gap and the rate of change in the electrical output of each of the solar cells is expressed by the formula Ln (Sm [mm]) = A × (Qm
[%]) + B, the cell gap between the plurality of solar cells is set, and by optimizing the cell gap between the solar cells,
The photovoltaic power generation conversion efficiency per one solar cell when the module is mounted can be improved.

According to the solar cell module of the second aspect of the present invention, the reflective material is made of a metallic material subjected to a matte surface treatment for improving scattering and reflection, or a resin mixed with a white pigment. It is characterized by comprising a conductive material, and can enhance the scattering / reflection effect of the light incident on the solar cell module, and can improve the photovoltaic power generation conversion efficiency.

According to the solar cell module of the present invention, the back cover member is made of a reflective material made of a resin material mixed with the white pigment and a weather resistant material made of a dielectric material. It is characterized by comprising at least two layers with a material, and can enhance the scattering / reflection effect of light incident on the solar cell module, and also enhance the weather resistance and electrical insulation of the solar cell module. .

According to the solar cell module of the fourth aspect of the present invention, at least the surface of the reflective material on which light is incident has an uneven shape. The effect of scattering and reflecting incident light can be enhanced, and the efficiency of photovoltaic power generation conversion can be improved.

According to the solar cell module of the present invention, the concave and convex shape of the reflective material is a triangular wave shape, a pyramid shape, or an inverted pyramid shape. Using the total reflection effect,
The effect of scattering and reflecting light incident on the solar cell module can be enhanced, and the efficiency of photovoltaic power generation conversion can be improved.

According to the solar cell module of the present invention, the cell gap Sm between the plurality of solar cells is 5 mm <Sm ≦ 100 mm, preferably 5 mm <Sm ≦ 30 mm. By further optimizing the cell gap between the solar cells, the solar power generation conversion efficiency per solar cell when the module is mounted can be improved.

Further, the solar cell module according to claim 7 of the present invention is characterized in that the reflective material has a surface reflectance of at least 70% or more, and the cell gap of the solar cell is reduced. Can be further optimized,
The photovoltaic power generation conversion efficiency per one solar cell when the module is mounted can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a basic principle of a solar cell module according to an embodiment of the present invention.

FIG. 2 is a plan view of a simulated solar cell module for confirming the principle of the solar cell module according to one embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the electric output change rate Qm and the cell gap Sm of the solar cell module according to one embodiment of the present invention.

FIG. 4 is a logarithmic graph showing a relationship between an electric output change rate Qm and a cell gap Sm of the solar cell module according to one embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing a configuration of a back cover member including the reflective member of the present invention.

FIG. 6 is a plan view of a solar cell module according to one embodiment of the present invention.

FIG. 7 is a partially enlarged sectional view taken along the line AA ′ of FIG. 6;

FIG. 8 is a perspective view showing an example of a conventional super straight type solar cell module.

FIG. 9 is an enlarged cross-sectional view showing a cross-sectional structure taken along a plane A in FIG. 8 of a conventional example.

FIG. 10 is an enlarged cross-sectional view showing details of a back cover member of a conventional super straight type solar cell module.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Transparent filling material 3 Front cover member (translucent) 4 Back cover member 5 Incident light 7 Back cover member with unevenness 41 Metallic film, or has a scattering reflection function with a dielectric film on the back surface Weather-resistant resin film 42 weather-resistant resin film having a transparent or scattering / reflection function 43 weather-resistant resin film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Tomita 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (7)

[Claims] 1. A front cover made of a plurality of solar cells arranged in a plane with a cell gap therebetween, and a translucent material commonly arranged on each light receiving surface side of the plurality of solar cells. A solar cell module comprising: a member and a back cover member that is disposed in common behind the plurality of solar cells and includes a reflective material that scatters and reflects light incident from the front through the cell gap. The light incident through the cell gap is reflected by the reflective material, further reflected again by the front cover member, and reaches the light receiving surfaces of the plurality of solar cells, and the plurality of solar cells Each of the cells allows the light energy incident on each light receiving surface to be converted into electric energy with higher efficiency, and the relationship between the cell gap and the rate of change in the electric output of each of the solar cells is So as to satisfy the equation, the solar cell module is characterized in that sets the plurality of solar cells each other cell gap. Ln (Sm [mm]) = A × (Qm [%]) + B where Ln is a natural logarithmic function, Sm is a cell gap, Qm is an electric output change rate, and A and B are constants. 2. The reflective material according to claim 1, wherein the reflective material is made of a metallic material that has been subjected to a matte surface treatment for improving scattering reflectivity, or a resinous material into which a white pigment is mixed. The solar cell module as described. 3. The back cover member comprises at least two layers of a reflective material made of a resin material mixed with the white pigment and a weather-resistant material made of a dielectric material. The solar cell module according to claim 1. 4. The reflective material according to claim 2, wherein at least a surface on which light is incident has an uneven shape.
Or the solar cell module according to 3. 5. The solar cell module according to claim 1, wherein the concave and convex shape of the reflective material is a triangular wave shape, a pyramid shape, or an inverted pyramid shape. 6. The cell gap Sm between the plurality of solar cells is 5 mm <Sm ≦ 100 mm.
2. The lens system according to claim 1, wherein mm <Sm ≦ 30 mm.
6. The solar cell module according to any one of items 1 to 5. 7. The solar cell module according to claim 1, wherein the reflective material has a surface reflectance of at least 70%.