Solar power generation system installation method and solar power generation system

Abstract

The present invention provides a method for installing a solar power generation system and a solar power generation system that can improve the conversion rate of solar energy into electric power per unit area and easily compensate for the loss of electric power due to deterioration over time, etc. [Solution] In a solar power generation system 1 having a first solar power generation system 10 including a first solar cell string 12 having a plurality of first solar cell modules 11 and a first power conversion device 13, and a second solar power generation system 20 including a second solar cell string 22 having a plurality of second solar cell modules 21 and a second power conversion device 23, a method for installing a solar power generation system and the solar power generation system 1 are characterized in that each second solar cell module 21 is installed on the back side of the first solar cell module 11 so as to generate power only using indirect sunlight.

Description

[Technical field]

[0001] The present invention relates to a method for installing a photovoltaic power generation system and a photovoltaic power generation system. [Background technology]

[0002] Conventionally, a known photovoltaic power generation system includes a photovoltaic string having a plurality of photovoltaic modules electrically connected in series with each other, and a power conversion device (PCS: power conditioner) electrically connected to the photovoltaic string, and is configured so that the generated power is connected to the power grid of a power transmission and distribution company by the power conversion device, or so that a power consumer can construct the power conversion device as their own facility and use the generated power for their own use (self-consumption). In such a photovoltaic power generation system, the plurality of photovoltaic modules are installed so that they do not overlap each other vertically.

[0003] In this type of photovoltaic power generation system, the power generation decreases due to the aging of the solar cell module, etc. Since the solar cell module is constructed by electrically joining materials with different thermal expansion coefficients, such as semiconductors and metals, the power generation capacity gradually decreases over the long term due to thermal stress caused by repeated changes in temperature day and night or season, and the components can also be suddenly damaged by lightning strikes, storms, etc., and it is inevitable that the solar cell module as a whole will fail to generate power due to these factors.

[0004] Meanwhile, in recent years, new solar cells have been developed that use perovskite crystals as the power generation layer (for example, see Non-Patent Document 1). Perovskite solar cells can be manufactured, for example, by a coating process or a printing process on a resin substrate, and therefore are expected to be manufactured at lower cost than silicon-based solar cells, and products that are lighter and more flexible than silicon-based solar cells can also be manufactured, so they are expected to be applied to a variety of uses. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Tsutomu Miyasaka, "The emergence of perovskite solar cells", Modern Chemistry, Tokyo Kagaku Dojin Co., Ltd., February 18, 2014, March 2014 issue, pp. 24-32 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a solar power generation system installed using conventional installation methods, the generated power supplied to the power conversion device from multiple solar cell modules is limited by the energy conversion efficiency of each solar cell module, so regardless of the type of solar cell module used, there was a problem in that the solar energy to power conversion rate (energy utilization rate) per unit area of ​​the solar power generation system could not be improved with the solar cell module alone.

[0007] Furthermore, when the power generated by an existing photovoltaic power generation system decreases due to aging of the solar cell module or the like, it is difficult to compensate for the decrease in power.

[0008] The present invention has been proposed in consideration of the above-mentioned problems, and an object of the present invention is to provide a method for installing a solar power generation system and a solar power generation system that can improve the conversion rate of solar energy to power per unit area and can easily compensate for the loss of power due to deterioration over time, etc. [Means for solving the problem]

[0009] The installation method of the photovoltaic power generation system of the present invention includes a first photovoltaic power generation system including a first solar cell string having a plurality of first solar cell modules electrically connected in series with each other and a first power conversion device electrically connected to the first solar cell string, and a second photovoltaic power generation system including a second solar cell string having a plurality of second solar cell modules electrically connected in series with each other and a second power conversion device electrically connected to the second solar cell string, the method comprising: installing each of the second solar cell modules on the back side of the first solar cell module so as to generate power only by indirect sunlight. a third solar cell string including a plurality of transparent third solar cell modules electrically connected in series with each other, and a third power conversion device electrically connected to the third solar cell string, the third solar cell modules are installed above the first solar cell modules so that each of the first solar cell modules generates power from sunlight transmitted through the third solar cell modules, and the second solar cell modules are installed below the first solar cell modules so that the light receiving surfaces of the second solar cell modules face the opposite side to the first solar cell modules. The present invention is characterized by the above.

[0010] In the method for installing a photovoltaic power generation system of the present invention having the above-mentioned configuration, it is preferable that the second solar cell module is a perovskite solar cell.

[0012] The solar power generation system of the present invention includes a first solar cell string including a plurality of first solar cell modules electrically connected in series with each other and a first power conversion device electrically connected to the first solar cell string, and a second solar cell string including a plurality of second solar cell modules electrically connected in series with each other and a second power conversion device electrically connected to the second solar cell string, wherein each of the second solar cell modules is installed on the back side of the first solar cell module so as to generate power only by indirect sunlight. The present invention further includes a third solar power generation system including a third solar cell string including a plurality of transparent third solar cell modules electrically connected in series with each other, and a third power conversion device electrically connected to the third solar cell string, wherein the third solar cell modules are installed above the first solar cell modules so that each of the first solar cell modules generates power from sunlight transmitted through the third solar cell modules, and each of the second solar cell modules is installed below the first solar cell modules so that a light receiving surface of the second solar cell module faces away from the first solar cell module. It is characterized by the fact that

[0013] In the solar power generation system of the present invention having the above configuration, the second solar cell module is preferably a perovskite solar cell. Effect of the Invention

[0015] According to the present invention, it is possible to provide a method for installing a solar power generation system and a solar power generation system that can improve the conversion rate of solar energy to electricity per unit area and easily compensate for the loss of power due to deterioration over time, etc. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram illustrating an outline of a configuration of a photovoltaic power generation system according to a first embodiment, which is installed by a method for installing a photovoltaic power generation system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a configuration of a first solar cell module shown in FIG. [Diagram 3] 2 is a diagram showing a configuration of a first solar cell string shown in FIG. 1. [Figure 4] 2 is a diagram showing a configuration of a second solar cell module shown in FIG. 1. [Diagram 5] 5 is a diagram showing a cross-sectional structure of the second solar cell module shown in FIG. [Figure 6] 2 is a diagram showing one embodiment of an arrangement of a plurality of first solar cell modules and a plurality of second solar cell modules in the solar power generation system shown in FIG. 1. FIG. [Figure 7] FIG. 7 is a side view of the solar power generation system shown in FIG. [Figure 8] 1. FIG. 4 is a diagram showing another embodiment of the arrangement of the plurality of first solar cell modules and the plurality of second solar cell modules in the solar power generation system shown in FIG. [Figure 9] FIG. 13 is a diagram illustrating an outline of a configuration of a solar power generation system according to a modified example. [Figure 10] 10 is a diagram showing one embodiment of an arrangement of a plurality of first solar cell modules, a plurality of second solar cell modules, and a plurality of third solar cell modules in a solar power generation system according to the modified example shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The installation method for a solar power generation system of the present invention is a method for installing a solar power generation system having a first solar cell string having a plurality of first solar cell modules electrically connected in series with each other and a first power conversion device electrically connected to the first solar cell string, and a second solar power generation system having a second solar cell string having a plurality of second solar cell modules electrically connected in series with each other and a second power conversion device electrically connected to the second solar cell string, characterized in that each second solar cell module is installed on the back side of the first solar cell module so as to generate power only from indirect sunlight.

[0018] The solar power generation system of the present invention is a solar power generation system having a first solar cell string having a plurality of first solar cell modules electrically connected in series with each other and a first power conversion device electrically connected to the first solar cell string, and a second solar cell string having a plurality of second solar cell modules electrically connected in series with each other and a second power conversion device electrically connected to the second solar cell string, characterized in that each second solar cell module is installed on the back side of the first solar cell module so as to generate power only using indirect sunlight.

[0019] The photovoltaic power generation system of the present invention can be installed by the method for installing a photovoltaic power generation system of the present invention.

[0020] As the first solar cell module, various types of solar cells can be used as long as they are capable of receiving sunlight and generating electricity. Also, the first solar cell string includes a plurality of first solar cell modules electrically connected in series with each other, and as long as each of the first solar cell modules is configured to receive global solar radiation including direct and indirect sunlight and generate electricity, the physical arrangement of the plurality of first solar cell modules can be appropriately set.

[0021] The multiple first solar cell modules can be physically arranged in a straight line while being electrically connected to each other in series, or can be arranged vertically in multiple stages (folded arrangement) while being electrically connected to each other in series.

[0022] The plurality of first solar cell modules may be of a transmissive type that transmits sunlight, or may be of a non-transmissive type that does not transmit sunlight.

[0023] As the second solar cell module, various types of solar cells can be used as long as they are capable of generating power by receiving indirect sunlight. Also, the second solar cell string includes a plurality of second solar cell modules electrically connected in series with each other, and as long as each second solar cell module is installed on the back side of the first solar cell module so as to generate power only by indirect light that does not include direct sunlight, the physical arrangement of each second solar cell module can be set appropriately.

[0024] The second solar cell modules may be electrically connected in series and physically arranged in a straight line, or may be electrically connected in series and arranged vertically in multiple stages (folded arrangement). The second solar power generation system may be installed in any position that does not reduce the power generation of the first solar power generation system.

[0025] The second solar cell modules may be of a transparent type that transmits sunlight or a non-transparent type that does not transmit sunlight, but it is preferable to use perovskite solar cells. Since perovskite solar cells can generate electricity efficiently even under low illuminance, by using perovskite solar cells as the second solar cell modules, it is possible to generate electricity effectively only from indirect light that does not include direct sunlight.

[0026] Here, direct sunlight refers to sunlight that directly reaches the solar cell module on a clear day when there is no scattering of sunlight by clouds. Indirect sunlight does not include direct sunlight, but refers to sunlight that is scattered by structures and the like on its way to the solar cell module and indirectly reaches the solar cell module, and also includes sunlight scattered by clouds and the like. In other words, the first solar power generation system is installed so that it can generate power from both direct and indirect sunlight, while the second solar power generation system is installed so that it can generate power only from indirect sunlight.

[0027] The back side of the first solar cell module refers to the side of the back side facing the opposite side to the light receiving surface of the first solar cell module, and is the area that overlaps with the first solar cell module when viewed from a direction perpendicular to the light receiving surface of the first solar cell module. In other words, the second solar cell module is installed so as to be hidden by the back side of the first solar cell module when viewed from a direction perpendicular to the light receiving surface of the first solar cell module.

[0028] The first solar cell module and the second solar cell module may be the same as each other in shape, size, number, and power generation performance, or may be different from each other.

[0029] Furthermore, the first solar power generation system may be one that has already been installed at the time when the second solar power generation system is installed, or may be one that is newly installed at the time when the second solar power generation system is installed.

[0030] According to the photovoltaic power generation system installation method and photovoltaic power generation system of the present invention having such a configuration, the first solar cell modules generate power by receiving direct and indirect sunlight, and the second solar cell modules generate power by indirect sunlight on the rear side of the first solar cell modules, respectively, so that the second solar cell system can be operated independently and in parallel with the first solar cell system. Also, since the second solar cell modules are all disposed on the rear side of the first solar cell modules, the conversion rate of solar energy to electricity per unit area in the entire place where the photovoltaic power generation system is installed can be increased.

[0031] Furthermore, according to the solar power generation system installation method or solar power generation system of the present invention, when the power generation of an existing solar power generation system decreases due to deterioration over time of the solar cell modules, by installing a plurality of second solar cell modules in the opposite direction to the back side of the plurality of first solar cell modules whose power generation has decreased due to deterioration over time, the power reduction due to deterioration over time can be easily compensated for by the power generation of the plurality of second solar cell modules.

[0032] Furthermore, according to the installation method and the solar power generation system of the present invention, the first solar cell module and the second solar cell module can be individually replaced, so that when the power generation performance of either the first solar cell module or the second solar cell module deteriorates, it is only necessary to use the one of the first solar cell module and the second solar cell module, the deterioration of which is tolerable, as it is, and to replace only the other, the deterioration of which is not tolerable, and there is no need to replace the first solar cell module and the second solar cell module at the same time. Therefore, according to the installation method and the solar power generation system of the present invention, the maintenance cost of the solar power generation system can be reduced.

[0033] The present invention will now be described in more detail with reference to the accompanying drawings.

[0034] A solar power generation system 1 according to an embodiment of the present invention shown in Fig. 1 is installed by a method for installing a solar power generation system according to an embodiment of the present invention. This solar power generation system 1 has a first solar power generation system 10 and a second solar power generation system 20.

[0035] The first solar power generation system 10 includes a first solar cell string 12 including a plurality of first solar cell modules 11 electrically connected in series with each other, and a first power conversion device (PCS: power conditioner) 13 electrically connected to the first solar cell string 12. The first power conversion device 13 converts DC power of the first solar cell string 12 into AC power.

[0036] 1, the first solar cell string 12 is configured such that a plurality of first solar cell modules 11 are arranged side by side in the horizontal direction of the page. There may be a gap (for example, about several mm) between adjacent first solar cell modules 11.

[0037] As long as the first solar cell string 12 has a plurality of first solar cell modules 11 electrically connected in series with each other, the physical arrangement of the plurality of first solar cell modules 11 can be changed as appropriate. In the case shown in FIG. 1, the first solar power generation system 10 is configured to have only one first solar cell string 12, but the present invention is not limited to this and the first solar cell system 10 can also have a solar cell array including a plurality of first solar cell strings 12. In this case, the plurality of first solar cell strings 12 may be electrically connected to each other using a connection box, and electrically connected to the first power conversion device 13 via the connection box.

[0038] The first power conversion device 13 is a so-called power conditioner (PCS) equipped with an inverter. The first power conversion device 13 converts DC power generated by the multiple first solar cell modules 11 into AC power and outputs it to the power grid. That is, the first solar power generation system 10 is configured such that the power generated by the multiple first solar cell modules 11 is interconnected with the power grid of the power transmission and distribution company by the first power conversion device 13.

[0039] When the first solar power generation system 10 is configured to have a plurality of first solar cell strings 12, the first power conversion device 13 can be configured to control power using an MPPT (Maximum Power Point Tracking) method so as to maximize the power generation of all of the first solar cell strings 12.

[0040] The first power conversion device 13 may be constructed as a home facility, and the power generated by the first solar power generation system 10 may be used at home (for home consumption).

[0041] The second solar power generation system 20 includes a second solar cell string 22 including a plurality of second solar cell modules 21 electrically connected in series with each other, and a second power conversion device (PCS: power conditioner) 23 electrically connected to the second solar cell string 22. The second power conversion device 23 converts the DC power of the second solar cell string 22 into AC power.

[0042] 1, the second solar cell string 22 is configured such that a plurality of second solar cell modules 21 are arranged side by side in the lateral direction of the page. There may be a gap (for example, about several mm) between adjacent second solar cell modules 21.

[0043] The physical arrangement of the second solar cell string 22 can be changed as appropriate as long as the second solar cell string 22 is installed on the back side of the first solar cell module 11 so that the second solar cell modules 21 are electrically connected to each other in series and generate power only by indirect light that does not include direct sunlight, as described below. In the case shown in FIG. 1, the second solar power generation system 20 is configured to include only one second solar cell string 22, but the present invention is not limited to this, and the second solar cell string 22 may be configured to include a solar cell array including multiple second solar cell strings 22. In this case, the multiple second solar cell strings 22 may be electrically connected to each other using a connection box and electrically connected to the second power conversion device 23 via the connection box.

[0044] The second power conversion device 23 is a so-called power conditioner (PCS) equipped with an inverter. The second power conversion device 23 converts DC power generated by the multiple second solar cell modules 21 into AC power and outputs it to the power grid. That is, the second solar power generation system 20 is configured such that the power generated by the multiple second solar cell modules 21 is interconnected with the power grid of the power transmission and distribution company by the second power conversion device 23.

[0045] When the second solar power generation system 20 is configured to include a plurality of second solar cell strings 22, the second power conversion device 23 can be configured to control power using an MPPT (Maximum Power Point Tracking) method so as to maximize the power generation of all of the second solar cell strings 22.

[0046] The second power conversion device 23 may be constructed as a home facility, and the power generated by the second solar power generation system 20 may be used at home (for home consumption).

[0047] In this manner, the solar power generation system 1 is configured such that the first solar power generation system 10 and the second solar power generation system 20 are solar power generation systems separate from each other, and these two solar power generation systems are configured to operate in parallel.

[0048] The installation method of the solar power generation system according to this embodiment is characterized in that, when installing the solar power generation system 1 having the above configuration at an installation location, each first solar cell module 11 is installed so as to receive global solar radiation including direct and indirect sunlight to generate power, and each second solar cell module 21 is installed on the back side of the first solar cell module 11 so as to generate power only from indirect sunlight. That is, in the solar power generation system 1, the multiple second solar cell modules 21 are installed on the back side of the first solar cell module 11 so as to generate power only from indirect light that does not include direct sunlight.

[0049] Thus, in the solar power generation system 1 installed by the solar power generation system installation method of this embodiment, the multiple first solar cell modules 11 are installed so that they can generate electricity by receiving global solar radiation including direct and indirect sunlight, whereas the multiple second solar cell modules 11 are installed on the back side of the first solar cell module 11 so that they can generate electricity only from indirect sunlight. Therefore, the multiple second solar cell modules 21, which are installed on the back side of the first solar cell module 11, thereby substantially eliminating the need to expand the installation space, can convert sunlight reflected around the solar power generation system 1 into electricity, thereby further increasing the conversion rate of solar energy to electricity per unit area of ​​the solar power generation system 1.

[0050] Furthermore, according to the installation method of the solar power generation system of this embodiment, by using an existing solar power generation system as the first solar power generation system 10, even if the power generation of the first solar power generation system 10 decreases due to deterioration over time of the solar cell modules 11, by installing multiple second solar cell modules 21 on the back side of the multiple first solar cell modules 11 whose power generation has decreased due to deterioration over time, the amount of power reduced due to deterioration over time of the solar cell modules 11 can be easily compensated for by the power generation of the multiple second solar cell modules 21.

[0051] Furthermore, in the solar power generation system 1 installed by the solar power generation system installation method of this embodiment, the first solar cell module 11 and the second solar cell module 21 can be replaced individually on each unit. Therefore, if the power generation performance of either the first solar cell module 10 or the second solar cell module 21 deteriorates, it is possible to continue to use the one of the first solar cell module 11 and the second solar cell module 21 whose power generation performance deterioration is tolerable, as is, and to replace only the other one whose power generation performance deterioration is not tolerable.

[0052] In the installation method for a solar power generation system according to this embodiment and the solar power generation system 1 according to this embodiment, a crystalline silicon solar cell is used as the first solar cell module 11, and a transparent perovskite solar cell is used as the second solar cell module 21. Note that the perovskite solar cell used as the second solar cell module 21 is not limited to a transparent type, and may be a non-transparent type.

[0053] As shown in FIG. 2, the first solar cell module 11 using a crystalline silicon solar cell has a configuration in which solar cells (power generating elements) 11a are aligned on a plane at regular intervals (for example, several mm). In the case shown in FIG. 2, the solar cell module 11 has eight solar cells 11a aligned in the vertical direction of the page and six solar cells aligned in the horizontal direction, forming a vertically long rectangular shape as a whole. For convenience, in FIG. 2, only one solar cell 11a is labeled with a reference symbol. A back sheet 11b is arranged on the rear side of the solar cell 11a, and the solar cell 11a is supported by a rectangular metal frame 11c on the outside of the back sheet 11b. In the solar cell module 11, the area surrounded by the four corners A, B, C, and D of the area in which the solar cells 11a are aligned in a rectangular shape is a power generating area that receives sunlight and generates power.

[0054] As shown in Fig. 3 by way of example for one solar cell module 11, each solar cell module 11 has, as its internal configuration, three cell strings 11d, each of which has 16 solar cells 11a arranged in two rows of eight cells each and electrically connected in series, and three bypass diodes (BD) 11e provided on a current path bypassing the cell strings 11d, and three clusters 11f, each of which is electrically connected in series with each other. In Fig. 3, a thick solid line indicates a path of a generated current of the first solar cell string 12. In Fig. 3, the current path surrounded by a dotted line includes three bypass diodes 11e housed in a junction box (not shown) installed on the back of each first solar cell module 11 and a generated current cable connecting each first solar cell module 11, and these are installed so as to be located on the back of the first solar cell module 11.

[0055] The bypass diode 11e operates when the voltage across a portion of the cell string 11d in the cluster 11f where the amount of power generated by the cell string 11d is relatively reduced due to non-uniform irradiation of the cell string 11d by a shadow, obstruction, etc., becomes higher than the voltage generated by the portion of the cell string 11d in the same cluster 11f that is generating power normally, and becomes equal to the forward voltage of the bypass diode 11e, and bypasses the generated current so as to bypass the cell string 11d, thereby preventing the occurrence of a hot spot in the cell string 11d. Therefore, when the entire solar cell module 11 is uniformly irradiated with sunlight, the sum of the electromotive forces generated by the power generation of each solar cell 11a becomes equal to or exceeds the forward voltage of the bypass diode 11e, so that the generated current flows in sequence through each cell string 11d without passing through the bypass diode 11e, as shown by the bold line in FIG.

[0056] The number of clusters 11f constituting the solar cell module 11 and the number of solar cells 11a constituting the clusters 11f can be changed as appropriate.

[0057] As shown in FIG. 4, the second solar cell module 21 using a transparent perovskite solar cell is in the form of a rectangular sheet having a rectangular power generating area 21a and a non-power generating area 21b provided around the entire periphery outside the power generating area 21a.

[0058] 5, the second solar cell module 21 using a transparent perovskite solar cell has a substrate 21c and a plurality of cells 21d provided on the substrate 21c. Each cell 21d has a configuration in which a transparent electrode 21e, an electron transport layer 21f, a perovskite power generation layer 21g, a hole transport layer 21h, and a back electrode 21i are laminated in this order.

[0059] The substrate 21c is formed of a material that can be treated as transparent (has almost no solar light absorption) in the wavelength range to which various solar cells are sensitive, such as a synthetic resin material such as polyethylene naphthalate (PEN), which is a polymer film having a relatively high heat resistance, or glass. When the substrate 21c is a polymer film, the solar cell module 21 can be made lighter and more flexible than when a glass substrate is used. On the other hand, when a glass substrate is used as the substrate 21c, it does not have flexibility but can have load resistance against wind pressure and the like.

[0060] The transparent electrode 21e may be, for example, a transparent conductive film (ITO). The electron transport layer 21f may be, for example, titanium oxide (TiO2). The perovskite power generation layer 21g may be, for example, an organic semiconductor material represented by the chemical formula CH3NH3Pbl3. The hole transport layer 21h has a function of moving holes generated by excitation by sunlight to the positive electrode, and may be, for example, Spiro-OMeTAD. Both the electron transport layer 21f and the hole transport layer 21h can be treated as transparent (almost no solar light absorption) in the wavelength range to which various solar cells are sensitive, similar to the substrate 21c. The back electrode 21i may be, for example, a transparent conductive oxide (TCO) formed of transparent conductive glass (FTO: fluorine-doped tin oxide).

[0061] The second solar cell module 21 using a transparent perovskite solar cell is formed, for example, through the steps of forming a multilayer film of a charge transport layer (hole transport layer 21h and electron transport layer 21f) and a perovskite power generation layer 21g on a layer of a transparent electrode 21e patterned on a substrate 21c, scribing to separate the charge transport layer and the perovskite power generation layer 21g, forming a film of a back electrode 21i, and separating the electrodes to electrically connect the cells 21d in series. The reason for separating the cells 21d by performing scribing from the layer of the transparent electrode 21e on the substrate 21c side to form a series connection structure is to suppress the series resistance of the second solar cell module 21, as is generally adopted in thin-film solar cells.

[0062] As shown by the thick arrow in FIG. 5, when sunlight enters from the substrate 21c side and reaches the perovskite power generation layer 21g of the cell 21d, charge carriers (electrons and holes) are generated by photoexcitation due to the semiconductor properties of the perovskite power generation layer 21g, and the electrons move to the electron transport layer 21f and the holes move to the hole transport layer 21h. The electrons move to the transparent electrode 21e on the substrate 21c side via the electron transport layer 21f, and then move to the negative electrode side electrode and combine with the holes generated by the adjacent cell 21d. In this way, as shown by the thick arrow in FIG. 5, the electrons generated by photoexcitation are transferred to the adjacent cell 21d one after another, and move to the negative electrode side of the second solar cell module 21. Since the direction of the generated current is opposite to the flow of electrons, the generated current flows from the negative electrode side to the positive electrode side of the second solar cell module 21 shown in FIG. 5.

[0063] The power generating region 21a of the second solar cell module 21 is a region in which the cells 21d of the second solar cell module 21 are present. On the other hand, the non-power generating region 21b of the second solar cell module 21 is a region formed by the substrate 21c in which the perovskite power generating layer 21g is not present in the second solar cell module 21. Therefore, the non-power generating region 21b does not generate power, so it does not absorb sunlight and has translucency.

[0064] In this way, the second solar cell module 21 using a transparent perovskite solar cell has transparent electrodes for both the positive and negative electrodes, making the second solar cell module 21 a transparent type that can transmit sunlight.

[0065] The perovskite solar cell constituting the second solar cell module 21 may have a back electrode 21i made of a metal such as gold or silver.

[0066] FIG. 6 is a diagram showing one embodiment of an arrangement of a plurality of first solar cell modules 11 and a plurality of second solar cell modules 21 in the solar power generation system 1 shown in FIG. 1, and FIG. 7 is a side view of the solar power generation system shown in FIG. 6.

[0067] In addition, in Figures 6 and 7, the same reference numerals are used for members or parts corresponding to the members or parts described above. In addition, in Figure 6, the orientation is such that the top of the paper is north, the bottom is south, the left side is west, and the right side is east.

[0068] In the photovoltaic power generation system 1 shown in FIG. 6, a first photovoltaic power generation system 10 has a configuration including a solar cell array including two first solar cell strings 12 arranged adjacent to each other in the east-west direction.

[0069] Of the two first solar cell strings 12, one of the first solar cell strings 12 arranged on the west side has eight first solar cell modules 11 arranged in two upper and lower stages, and the first solar cell modules 11 adjacent to each other in a counterclockwise direction from the easternmost first solar cell module 11 in the upper stage to the easternmost first solar cell module 11 in the lower stage are electrically connected in series to form one of the first solar cell strings 12. The first solar cell module 11 located in the easternmost side of the upper stage and the first solar cell module 11 located in the easternmost side of the lower stage are each connected to a first power converter 13. Similarly, of the two first solar cell strings 12, the other of the two first solar cell strings 12 arranged on the east side has eight first solar cell modules 11 arranged in two upper and lower stages, and the first solar cell module 11 adjacent to each other in a counterclockwise direction from the westernmost first solar cell module 11 in the upper stage to the westernmost first solar cell module 11 in the lower stage are electrically connected in series to form the other of the first solar cell strings 12. The first solar cell module 11 located on the westernmost side of the upper stage and the first solar cell module 11 located on the westernmost side of the lower stage are each connected to a first power conversion device 13. In this manner, a first solar power generation system 10 is configured.

[0070] The power conversion device 13 may be one in which the multiple first solar cell strings 12 are directly connected, or may be one in which the multiple first solar cell strings 12 are connected via a connection box (not shown).

[0071] As shown in FIG. 7, the two first solar cell strings 12 are supported by a south pillar 30 and a north pillar 31, respectively, and are installed above ground 32 at an angle such that the north side is higher than the south side.

[0072] In the solar power generation system 1 shown in Fig. 6, the second solar power generation system 20 has eight second solar cell modules 21. The eight second solar cell modules 21 are arranged in a horizontal row from west to east and electrically connected in series to configure a second solar cell string 22. The two second solar cell modules 21 at both ends are each connected to a second power conversion device 23, thereby configuring the second solar power generation system 20.

[0073] The eight second solar cell modules 21 are installed on the back side of the first solar cell module 11, facing the opposite side to the first solar cell module 11. That is, the eight second solar cell modules 21 are installed back-to-back to the first solar cell module 11. More specifically, as shown in FIG. 6 and FIG. 7, the eight second solar cell modules 21 are installed on the back side of the corresponding first solar cell module 11 of the eight first solar cell modules 11 arranged on the north side across the two first solar cell strings 12, facing the opposite side to the first solar cell module 11. As a method of installing the second solar cell module 21 back-to-back to the first solar cell module 11, an appropriate method or structure may be used, for example, a method of fixing the first solar cell module 11 and the second solar cell module 21 in a state of being stacked on each other using a clamp.

[0074] It is preferable to use a non-transparent type as the first solar cell module 11, and a crystalline silicon solar cell or a multi-stage perovskite solar cell including a non-transparent type at the bottom stage is applicable. It is preferable to use a perovskite solar cell that efficiently generates power even under low illuminance as the second solar cell module 21.

[0075] With this arrangement, each first solar cell module 11 receives direct sunlight and generates electricity, and since each first solar cell module 11 is non-transparent, each second solar cell module 21 can generate electricity only from indirect sunlight, such as light reflected by the ground 32 and a structure 33 such as a wall adjacent to the solar power generation system 1.

[0076] In this case, the second solar cell module 21 is positioned behind the first solar cell module 11, biased toward the north, so that it can receive more indirect sunlight, such as light reflected by the ground 32 and a structure 33 provided adjacent to the solar power generation system 1, thereby enabling more efficient power generation.

[0077] The solar power generation system 1 is not limited to a configuration in which eight second solar cell modules 21 are installed back-to-back to the first solar cell module 11 as shown in FIG. 7, but may also be configured in such a way that the eight second solar cell modules 21 are installed vertically to the ground 32 and facing north on the rear side of the first solar cell module 11 using a north-side support 31 as shown in FIG. 8.

[0078] Even with this arrangement, each of the first solar cell modules 11 receives direct sunlight to generate power, and each of the second solar cell modules 21 faces north, so that it can generate power only from indirect sunlight, such as light reflected by a structure 33 installed adjacent to the solar power generation system 1. In addition, in a field solar power plant equipped with many solar power generation systems, a plurality of solar cell arrays are installed in parallel in the north-south direction, so that the reflected light of direct sunlight is received by the first solar cell module 11 of the solar cell array adjacent to the north side and by the second solar cell module 21 of the solar cell array on the south side, the reflected light of direct sunlight can be efficiently used for power generation in the second solar power generation system 20. Therefore, the conversion rate of solar energy to electricity per unit area can be further improved.

[0079] As shown as a modified example in Figures 9 and 10, the installation method of the solar power generation system according to this embodiment includes a third solar cell string 42 having a plurality of transparent third solar cell modules 41 electrically connected in series with each other, and a third power conversion device 43 electrically connected to the third solar cell string 42. The third solar cell module 41 is installed above the first solar cell module 11 so that each first solar cell module 11 generates power from sunlight that has passed through the third solar cell module 41, and each second solar cell module 21 is installed below the first solar cell module 11 so that they face the opposite side to the first solar cell module 11. That is, the solar power generation system 1 of this embodiment further includes a third solar cell string 42 having a plurality of transparent third solar cell modules 41 electrically connected in series with each other, and a third power conversion device 43 electrically connected to the third solar cell string 42, and the third solar cell module 41 is installed above the first solar cell module 11 so that each first solar cell module 11 generates power from sunlight that has passed through the third solar cell module 41, and each second solar cell module 21 is installed below the first solar cell module 11 so that they face the opposite side to the first solar cell module 11.

[0080] In the solar power generation system 1 according to this modified example, the third solar cell string 42 is configured such that a plurality of transparent third solar cell modules 41 are arranged on the upper side of a plurality of first solar cell modules 11, side by side with respect to each other in the horizontal direction of the page.

[0081] In this manner, in the installation method for a solar power generation system and the solar power generation system 1 according to the modified example, a configuration is adopted in which a plurality of third solar cell strings 42 are stacked above a plurality of first solar cell modules 11 so that each first solar cell module 11 generates power from sunlight that has passed through the transparent third solar cell module 41, i.e., a configuration in which the second solar cell string 22 is stacked above the first solar cell string 12.

[0082] Therefore, in a solar power generation system 1 installed using the installation method for a solar power generation system according to the modified example, the multiple transparent third solar cell modules 41 can each generate electricity by receiving direct sunlight, the multiple first solar cell modules 11 can each generate electricity from sunlight that is not generated by the transparent third solar cell modules 41 but is transmitted through the transparent third solar cell modules 41, and the multiple second solar cell modules 21 can each generate electricity from reflected sunlight reflected around the solar power generation system 1, i.e., indirect sunlight, thereby further increasing the conversion rate of solar energy to electricity per unit area of ​​the solar power generation system 1.

[0083] In this modification, it is preferable to use a transparent perovskite solar cell as shown in Figs. 4 and 5 as the third solar cell module 41, but a transparent solar cell module of another structure may also be used.

[0084] In this modification, various types of solar cells can be used as the first solar cell module 11 of the first solar power generation system 10, such as transparent or non-transparent perovskite solar cells, crystalline silicon solar cells, and CIS solar cells.

[0085] In addition, in this modification, various types of solar cells can be used as the second solar cell module 21 of the second solar power generation system 20, such as transparent or non-transparent perovskite solar cells, crystalline silicon solar cells, and CIS solar cells.

[0086] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0087] 1. Solar power generation system 10 The first solar power generation system 11 First solar cell module 11a Solar cell 11b Back sheet 11c Metal Frame 11d Cell String 11e Bypass Diode 11f Cluster 12 First solar cell string 13 First power conversion device 20 Second Solar Power System 21 Second solar cell module 21a Power Generation Area 21b Non-power generation area 21c board 21d Cell 21e transparent electrode 21f Electron transport layer 21g Perovskite power generation layer 21h Hole transport layer 21i back electrode 22 Second solar string 23 Second power conversion device 30 South pillar 31 North pillar 32 Ground 33 Structures 40 The third solar power generation system 41 Third solar cell module 42 3rd solar string 43 Third power conversion device A corner B corner C corner D angle

Claims

1. A first solar power generation system including a first solar cell string including a plurality of first solar cell modules electrically connected in series with each other, and a first power conversion device electrically connected to the first solar cell string; a second solar cell string including a plurality of second solar cell modules electrically connected in series with each other, and a second power conversion device electrically connected to the second solar cell string; and In a solar power generation system having Each of the second solar cell modules is installed on a rear side of the first solar cell module so as to generate electricity only by indirect sunlight; A method for installing a solar power generation system, comprising: a third solar cell string including a plurality of transparent third solar cell modules electrically connected in series with each other; and a third power conversion device electrically connected to the third solar cell string, the method comprising: installing the third solar cell module above the first solar cell module so that each of the first solar cell modules generates power from sunlight that has passed through the third solar cell module; and installing each of the second solar cell modules below the first solar cell module so that the light receiving surface of the second solar cell module faces away from the first solar cell module.

2. The method for installing a solar power generation system according to claim 1 , wherein the second solar cell module is a perovskite solar cell.

3. A first solar power generation system including a first solar cell string including a plurality of first solar cell modules electrically connected in series with each other, and a first power conversion device electrically connected to the first solar cell string; a second solar cell string including a plurality of second solar cell modules electrically connected in series with each other, and a second power conversion device electrically connected to the second solar cell string; and A solar power generation system having: Each of the second solar cell modules is installed on a rear side of the first solar cell module so as to generate power only by indirect light of sunlight; a third solar cell string including a plurality of third transparent solar cell modules electrically connected in series to each other; and a third power conversion device electrically connected to the third solar cell string; a third solar cell module is installed above the first solar cell module so that each of the first solar cell modules generates electricity from sunlight that has passed through the third solar cell module, and each of the second solar cell modules is installed below the first solar cell module so that the light receiving surface of the second solar cell module faces away from the first solar cell module.

4. The solar power generation system according to claim 3 , wherein the second solar cell module is a perovskite solar cell.

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