JP7597689B2 - Solar cell modules and solar power generation systems - Google Patents

Description

The present invention relates to a solar cell module and a solar power generation system using the same.

In recent years, split cells have become the mainstream for solar cell modules (see, for example, Patent Document 1). A split cell here refers to a small cell that is a split from a standard-sized cell (a cell equivalent to one solar cell wafer, also known as a full cell), such as a half cell that is a full cell split in half. With a half cell, the current value per cell can be halved compared to a full cell, which reduces the power loss of the solar cell module.

If a solar cell module formed by connecting multiple full cells in series generates a current of 10A, to obtain a similar current in a solar cell module using half cells, two strings of multiple half cells connected in series must be connected in parallel. In other words, since one string generates a current of 5A, a current of 10A can be obtained by connecting two strings in parallel.

A common way to use solar cell modules is to line up multiple modules on a roof or other surface and connect them together to form a solar power generation system. When installing a solar power generation system on a hipped roof or the like, a rectangular module is combined with a polygonal (e.g., pentagonal) corner module (see, for example, Patent Document 2).

JP 2020-98931 A Patent No. 2017-112175

When connecting a rectangular module and a corner module in a solar power generation system, it is necessary to align the output characteristics of each module. In corner modules, in which cells are arranged in a stepped pattern, the number of cells is adjusted to align the output characteristics, and if the area where no cells are arranged becomes large, the cell packing rate relative to the module area appears low, which can lead to problems such as a loss of aesthetic appeal.

Patent Document 2 discloses a corner module in which dummy cells are placed in the empty areas of the corner module (areas where no cells are placed) to prevent deterioration of the aesthetic appearance. However, providing dummy cells that do not contribute to power generation is disadvantageous in terms of cost.

The present invention was made in consideration of the above problems, and aims to provide a solar cell module and a solar power generation system that can increase the cell packing rate relative to the module area without using dummy cells in the corner module.

In order to solve the above problems, the solar cell module according to the first aspect of the present invention is characterized in that a plurality of solar cell groups are formed by connecting a plurality of solar cell cells in series, the plurality of cell groups are connected by intermediate electrode wiring to form a plurality of strings, the plurality of strings are connected in parallel, the solar cell is a divided cell, the number of cells in each row of the cell groups is all different, and the difference in the number of cells in adjacent rows of the cell groups is not constant.

The above configuration allows the corner module to have a high cell packing rate relative to the module area, improving the aesthetic appearance of the solar cell module.

In addition, the solar cell module can be configured so that the difference in the number of cells between adjacent cell rows is within one full cell.

The above configuration makes it possible to prevent the creation of large spaces larger than the size of one full cell in areas where no cells are installed, thereby further improving the aesthetic appearance of the solar cell module.

In addition, in the solar cell module, the difference in the number of cells between adjacent cell rows can be configured to be smaller than one full cell.

The above configuration allows the areas in each row of cell groups where no cells are installed to be closer to an even space, further improving the aesthetics of the solar cell module.

In order to solve the above problem, the solar cell module according to the second aspect of the present invention has a plurality of cell rows formed in a stepped shape, a plurality of solar cell groups each connected in series, a plurality of cell groups each connected by intermediate electrode wiring to form a plurality of strings, the plurality of strings connected in parallel, the solar cell being a divided cell, string switching being performed midway in at least one of the cell rows, and an end electrode wiring connected to the end of the string being disposed midway in the cell row where the string switching is being performed.

The solar cell module can also be configured so that the number of cells in each string is the same.

The above configuration allows the voltage in each string to be the same, preventing backflow between different strings and effectively preventing power loss.

In order to solve the above problems, the solar power generation system according to the third aspect of the present invention is a solar power generation system that combines a corner module and a rectangular module, and is characterized in that the corner module is the solar cell module described above.

In addition, in the above solar power generation system, the corner module and the rectangular module can be configured to use the same type of divided cells.

According to the above configuration, by using the same type of divided cells in the corner module and the rectangular module, the aesthetics of the entire solar power generation system can be improved.

The solar cell module and solar power generation system of the present invention have the advantage that the cell packing rate relative to the module area can be increased in corner modules, improving the aesthetic appearance.

1 is a plan view illustrating an example of a solar cell module according to a first embodiment. 1 is a plan view illustrating a modified example of the solar cell module according to the first embodiment. FIG. FIG. 11 is a plan view illustrating an example of a solar cell module according to a second embodiment. 13 is a plan view showing an example of an arrangement of corner modules and rectangular modules in a solar power generation system according to embodiment 3. FIG.

[First embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

Figure 1 is a plan view that shows a schematic example of a solar cell module M1 according to the present embodiment. The solar cell module M1 is a corner module with a polygonal shape (pentagonal shape in this example) that has right-angled corners and corners at angles other than right angles, and is configured with multiple cell rows formed in a stepped shape. Note that the solar cell module M1 shown in Figure 1 may be configured so that the polarity is reversed.

The solar cell module M1 has two strings connected in parallel, namely, a first string S(1) and a second string S(2). The first string S(1) has a plurality of cell groups CG(1,1) to CG(1,n1) (n1 is an integer of 2 or more). The second string S(2) has a plurality of cell groups CG(2,1) to CG(2,n2) (n2 is an integer of 2 or more). In the solar cell module M1 shown in FIG. 1, n1=2 and n2=4. In the configuration of FIG. 1, each cell group CG constitutes a different cell row, and there is a one-to-one correspondence between the cell group CG and the cell row.

The cell groups in the first string S(1) and the second string S(2) are connected by intermediate electrode wiring La (busbars). In each of the first string S(1) and the second string S(2), the solar cell cells C are connected in series. The intermediate electrode wiring La is an electrode wiring that connects the ends of the cell groups CG included in the same string.

More specifically, in the first string S(1) and the second string S(2), the solar cell C is arranged in a row in a predetermined row direction X. The first string S(1) and the second string S(2) are arranged side by side in the perpendicular direction Y. In each of the first string S(1) and the second string S(2), the cell groups CG(1,1) to CG(1,n1) and CG(2,1) to CG(2,n2) are arranged side by side in the perpendicular direction Y. The end electrode wiring Lb (bus bar) connected to at least one side of the cell groups CG(1,1) to CG(1,n1) and CG(2,1) to CG(2,n2) is provided at at least one end in the row direction X. In the example shown in FIG. 1, the end electrode wiring Lb connected to both sides of the cell groups CG(1,1) to CG(1,n1) and CG(2,1) to CG(2,n2) is provided at the end of one side (X1) in the row arrangement direction X. The end electrode wiring Lb is the electrode wiring connected to the end of each string.

In the example shown in FIG. 1, the end electrode wiring Lb of cell group CG(1,1) and the end electrode wiring Lb of cell group CG(2,n2) are connected to a cathode connecting electrode wiring (not shown). The end electrode wiring Lb of cell group CG(1,n1) and cell group CG(2,1) are connected to an anode connecting electrode wiring (not shown). This results in a parallel connection of the first string S(1) and the second string S(2) in the solar cell module M1.

In this embodiment, the solar cell C in the solar cell module M1 is exemplified by dividing a solar cell (full cell) substrate having a size of about 160 mm square into two. In other words, after division, the solar cell C becomes a half cell having an overall size of about 160 mm x 80 mm square. Note that the specific configuration of each solar cell C and the connection configuration of the solar cell C within the cell groups CG(1,1) to CG(1,n1) and CG(2,1) to CG(2,n2) are publicly known, so a detailed description will be omitted here.

In the solar cell module M1, the number of solar cell C cells in the first string S(1) on one side is equal to the number of solar cell C cells in the second string S(2) on the other side. In the example shown in FIG. 1, the number of cells in each of the first string S(1) and the second string S(2) is 22. In this way, by making the number of solar cell C cells in the first string S(1) and the second string S(2) equal, the voltage can be made the same in the one string S(1) and the other string S(2). This makes it possible to avoid the occurrence of backflow between the one string S(1) and the other string S(2), and effectively prevent power loss.

The solar cell module M1 has six rows of cells, but the number of cells in each row is different, and the cells are arranged in a stepped manner so that the number of cells changes monotonically along the orthogonal direction Y. Specifically, the number of cells in cell group CG (1,1) is 12, cell group CG (1,n1) is 10, cell group CG (2,1) is 8, cell group CG (2,2) is 6, cell group CG (2,3) is 5, and cell group CG (2,n2) is 3. In this embodiment 1, since the cell groups CG and the cell rows correspond one-to-one in the solar cell module M1, the number of cells in each cell group CG is also used to mean the number of cells in each row.

In addition, in solar cell module M1, the difference in the number of cells between adjacent cell rows is not constant. Specifically, the difference in the number of cells between cell group CG(2,2) and cell group CG(2,3) is one sheet, but the difference in the number of cells between the other adjacent cell rows is two sheets.

In a corner module in which solar cell C are arranged in a stepped pattern, it is necessary to efficiently lay out the cells on the polygonal module surface and prevent deterioration of the aesthetic appearance. Furthermore, when multiple strings are connected in parallel in a corner module, it is necessary to align the voltage in each string (i.e., align the number of cells in each string). By varying the difference in the number of cells between adjacent cell rows, rather than keeping it constant, it is possible to efficiently lay out the cells according to the shape of the polygonal module surface.

In the solar cell module M1 according to the first embodiment, the difference in the number of cells between adjacent cell rows is not constant, and by arranging all cell rows so that the number of cells is different (no cell rows have the same number of cells), it is possible to increase the cell filling rate relative to the module area and improve the aesthetics. In addition, because the number of cells is different in all cell rows, it is possible to reduce the distance between the hypotenuse of the polygonal module and cell C at the end of the cell row, which increases the cell filling rate relative to the module area and increases the output of the module.

As a more preferable condition, in the solar cell module M1, the difference in the number of cells between adjacent cell rows is within a maximum of one full cell (two half cells). In addition, the difference in the number of cells between adjacent cell rows is made smaller than one full cell. In the example of FIG. 1, the difference in the number of cells between adjacent rows is two half cells at the most and one half cell at the least (between cell group CG (2,2) and cell group CG (2,3)), so the difference in the difference in the number of cells is one half cell. Furthermore, the location where the difference in the number of cells differs is not on the end side in the arrangement direction of the cell rows (orthogonal direction Y) but on the inside. In the example of FIG. 1, the location where the difference in the number of cells between adjacent rows differs is between cell group CG (2,2) and cell group CG (2,3). As a result, even if the difference in the number of cells between adjacent cell rows is not constant, the difference in the difference in the number of cells is less noticeable, the cell packing rate relative to the module area can be increased, and the aesthetic appearance can be improved.

In addition, in solar cell module M1, it is preferable that the number of cells in the cell row with the smallest number of cells is greater than the maximum difference in the number of cells between adjacent cell rows. In the example of Figure 1, the cell row with the smallest number of cells is cell group CG(2,n2), which has three cells. On the other hand, the maximum difference in the number of cells between adjacent cell rows is two. With this cell arrangement, solar cell module M1 appears to have a high cell filling rate.

2 is a plan view showing a schematic diagram of a modified example of the solar cell module M1 according to the present embodiment. In the example of FIG. 2, the solar cell cells C are arranged so that the polarity of the second string S(2) is reversed from that of FIG. 1. In the example shown in FIG. 2, the end electrode wiring Lb of the cell group CG(1,1) and the end electrode wiring Lb of the cell group CG(2,1) are connected to a cathode connection electrode wiring (not shown). The end electrode wiring Lb of the cell group CG(1,n1) and the end electrode wiring Lb of the cell group CG(2,n2) are connected to an anode connection electrode wiring (not shown). The solar cell cells C may be arranged so that the polarity of the first string S(1) is reversed from that of FIG. 1.

[Embodiment 2]
In the first embodiment, a solar cell module M1 using half cells as the solar cell C is exemplified. However, the present invention is not limited to this, and other divided cells can be used as the solar cell C. In the second embodiment, a solar cell module M2 using 1/3 cells as the solar cell C is exemplified. Fig. 3 is a plan view that shows a schematic example of a solar cell module M2 according to the present embodiment.

The solar cell module M2 has three strings connected in parallel to each other, namely, the first string S(1), the second string S(2), and the third string S(3). The first string S(1) has a plurality of cell groups CG(1,1) to CG(1,n1) (n1 is an integer of 2 or more). The second string S(2) has a plurality of cell groups CG(2,1) to CG(2,n2) (n2 is an integer of 2 or more). The third string S(3) has a plurality of cell groups CG(3,1) to CG(3,n3) (n3 is an integer of 2 or more). In the solar cell module M2 shown in FIG. 1, n1=2, n2=2, and n3=3.

Cell groups CG(1,1) to CG(1,n1), CG(2,1) to CG(2,n2), and CG(3,1) to CG(3,n3) are each connected by intermediate electrode wiring La (busbar). In these cell groups, the solar cell C is connected in series.

In the example shown in FIG. 3, the end electrode wiring Lb of the cell group CG (1, n1), the end electrode wiring Lb of the cell group CG (2, n2), and the end electrode wiring Lb of the cell group CG (3, n3) are connected to the cathode connection electrode wiring (not shown). The end electrode wiring Lb of the cell group CG (1, 1), the cell group CG (2, 1), and the cell group CG (3, 1) are connected to the anode connection electrode wiring (not shown). As a result, the first string S (1), the second string S (2), and the third string S (3) in the solar cell module M2 are connected in parallel. In the example shown in FIG. 3, the number of cells in each of the first string S (1), the second string S (2), and the third string S (3) is 24. In addition, in the example of FIG. 3, the solar cell C may be arranged so that the polarity is reversed in any of the first string S (1), the second string S (2), and the third string S (3).

In this way, when split cells obtained by dividing a full cell into 1/m (m is a natural number equal to or greater than 2) are used as solar cell C, a solar cell module in which m strings are connected in parallel can obtain the same current as a solar cell module formed by connecting a full cell in series.

In a corner module, the solar cell C is arranged in a stepped manner, so that in a configuration where one cell group corresponds to one cell row, it is not easy to align the number of cells in each string. This is especially true when trying to increase the cell packing rate in the module. In contrast, the solar cell module M2 in FIG. 3 allows one cell row to include multiple cell groups, and adopts a configuration in which strings are switched in the middle of the cell row. Specifically, the second cell row from the right in FIG. 3 includes a cell group CG (1, n1) belonging to the first string S (1) and a cell group CG (2, 1) belonging to the second string S (2), and switching is performed from the first string S (1) to the second string S (2). In the example in FIG. 3, there is only one cell row in which string switching is performed in the middle, but there may be two or more cell rows in which string switching is performed in the middle.

In addition, when string switching is performed in the middle of a cell row, at the string switching point in this cell row, the end electrode wiring Lb is arranged using the area of one cell in the middle of the cell row, making it easy to align the number of cells in each string. In addition, in a cell row where string switching is performed in the middle and end electrode wiring Lb is arranged in the middle, the arrangement area of the end electrode wiring Lb is also counted as the apparent number of cells. That is, in the cell row second from the right in Figure 3, the number of solar cell cells C actually arranged is 15, but the number of cells in this cell row is counted as 16.

Third Embodiment
In the third embodiment, an example of a solar power generation system configured by combining a corner module and a rectangular module will be described.

Figure 4 is a plan view showing an example of the arrangement of solar cell module M1, which is a corner module, and solar cell module M3, which is a rectangular module, in a solar power generation system. Note that the number and arrangement layout of the corner modules and rectangular modules used in the solar power generation system according to the third embodiment are not particularly limited. However, each module used in the solar power generation system is connected in series with each other, and the system current in each module needs to be the same current (e.g., 10 A).

The solar cell module M3 shown in FIG. 4 uses half cells as solar cell cells C, and uses two strings in parallel, each of which is made up of multiple half cells connected in series. Note that a detailed description of the layout of the strings and electrode wiring within the solar cell module M3 will be omitted.

When using half cells in a rectangular module in a solar power generation system, it is preferable to also use half cells in the corner module, as this improves the aesthetic appearance of the solar power generation system. This is not limited to half cells, and it is preferable to use the same type of solar cell in the rectangular module and the corner module. For example, the solar cell types used in both the rectangular module and the corner module may be 1/3 cells.

However, the present invention is not limited to this, and the solar cells used in the rectangular module and the corner module may be different. For example, the corner module may use half cells, and the rectangular module may use full cells. Even in this case, the current must be the same in the corner module and the rectangular module, so the corner module must use two half cells in parallel, and the rectangular module must use one full cell in series.

The embodiments disclosed herein are illustrative in all respects and are not intended to be a basis for a restrictive interpretation. Therefore, the technical scope of the present invention is not to be interpreted solely by the above-described embodiments, but is defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included.

C Solar cell CG Cell group La Intermediate electrode wiring Lb End electrode wiring M1 to M3 Solar cell module S String

Claims (7)

The solar cell array has a plurality of cell rows formed in a stepped shape, and a plurality of solar cell groups are formed by connecting the plurality of solar cell rows in series, and the plurality of cell groups are connected by intermediate electrode wirings to form a plurality of strings, and the plurality of strings are connected in parallel,
The solar cell is a divided cell,
The number of cells in each cell row is different;
A solar cell module, characterized in that the difference in the number of cells between adjacent cell rows is not constant. The solar cell module according to claim 1 ,
A solar cell module, characterized in that the difference in the number of cells between adjacent cell rows is within the number of full cells. The solar cell module according to claim 1 or 2,
A solar cell module, characterized in that the difference in the number of cells between adjacent cell rows is smaller than that of one full cell. The solar cell array has a plurality of cell rows formed in a stepped shape, and a plurality of solar cell groups are formed by connecting the plurality of solar cell rows in series, and the plurality of cell groups are connected by intermediate electrode wirings to form a plurality of strings, and the plurality of strings are connected in parallel,
The solar cell is a divided cell,
A solar cell module characterized in that in at least one of the cell rows, string switching is performed midway, and in the cell row where string switching is performed, end electrode wiring connected to the end of the string is arranged midway in the cell row. The solar cell module according to claim 1 ,
A solar cell module, characterized in that the number of cells in each of the strings is the same. A solar power generation system comprising a combination of corner modules and rectangular modules,
A photovoltaic power generation system, wherein the corner module is the solar cell module according to any one of claims 1 to 5. The solar power generation system according to claim 6,
A solar power generation system, wherein the corner module and the rectangular module use the same type of divided cells.

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