JP7439107B2 - Solar strings and solar power systems - Google Patents

Description

Embodiments according to the present invention relate to a solar cell string and a solar power generation system.

A solar power generation system includes a solar module that receives light and generates DC power, and a power conditioner that converts the DC power generated by the solar module into AC power and sends it to the power grid.

In recent years, the development of so-called mega solar systems, which have a power generation capacity exceeding 1 MW, has been progressing. A mega solar system is a solar power generation system that includes several thousand or more solar cell modules each having a power generation capacity of several tens of watts. A solar power generation system such as a mega solar system includes a plurality of solar cell modules to obtain a desired power generation capacity. In a solar power generation system, a plurality of solar cell modules are electrically connected in series to increase the output voltage, and the solar cell modules connected in series are electrically connected in parallel to increase the output current. Here, a plurality of solar cell modules that are electrically connected in series are called a solar cell string, and a plurality of solar cell strings that are electrically connected in parallel are called a solar cell array.

FIG. 3 is a schematic diagram showing a conventional solar power generation system. The solar power generation system 1 shown in FIG. 3 includes a solar cell string 3. The solar power generation system 1 shown in FIG. In the solar cell string 3, a plurality of (for example, six) solar cell modules 2 are linearly arranged. The solar cell modules 2 are arranged in the same direction, and a terminal box (also referred to as a junction box) 11 is installed in the center of each solar cell module 2 near the top. A positive cable 12 and a negative cable 13 (hereinafter also simply referred to as cables 12 and 13) are attached to the terminal box 11.

In order to electrically connect the respective solar cell modules 2 in series, the cables 12 and 13 are connected to the cables 12 and 13 of the solar cell module 2 located next to each other when the solar cell modules 2 are lined up in a line. It has a connectable length. The cables 12, 13 are also provided with connectors at their respective free ends. Connectors can be electrically connected to each other. In the solar cell string 3, the cables 12 and 13 of the solar cell modules 2 located next to each other are electrically connected to form a series circuit 15 that electrically connects the solar cell modules 2 in series. be done.

Japanese Patent Application Publication No. 2017-174702

In recent years, there has been a demand for even higher efficiency of solar power generation systems. Therefore, a half-cell module in which the cell size is halved has been proposed as a solar cell module. As shown in FIG. 4, in the solar cell module 2 employing a half-cell module, cluster A and cluster B are divided into two in the vertical direction.

In the solar cell module 2 shown in FIG. 4, there is not one terminal box to which the cables 12 and 13 are attached, but a positive terminal box 112 and a negative terminal box 113. The positive terminal box 112 is arranged on the left side edge. The negative terminal box 113 is arranged on the right side edge.

By the way, in both the solar cell string 3 shown in FIG. 3 and the solar cell string 3 shown in FIG. 4, there are four cable connections in which the cables 12 and 13 of the solar cell modules 2 are connected, one by one. In the solar cell string 3 shown in FIG. 3, the cable lengths of the cable connectors are approximately equal, and even including the extra length, are approximately twice the width of the solar cell module 2.

On the other hand, in the solar cell string 3 shown in FIG. 4, there are two types, one with a long cable length and the other with a short cable length. When the six solar cell modules 2 are 2A, 2B, 2C, 2D, 2E, and 2F in order from the left side of FIG. One is connected to the negative terminal box 113 of the battery module 2D, and the other is connected from the positive terminal box 112 of the solar cell module 2D to the negative terminal box 113 of the solar cell module 2F.

In other words, since the positive terminal box 112 and the negative terminal box 113 are provided on the left and right side edges of the solar cell module 2, the one with the longer cable length among the cable connectors connecting the cables 12 and 13 is It extends over the solar cell module 2. In this way, when a half-cell module is adopted, the terminal boxes 112 and 113 are arranged in two parts in the left and right direction, which increases the cable length of the cable connection body that connects the cables 12 and 13. . As a result, the cable lengths of the cables 12 and 13 themselves had to be lengthened, leading to an increase in power loss and a rise in cost.

An object of the present invention is to provide a solar cell string and a solar power generation system that can shorten the cable length and suppress increases in power loss and costs.

In order to solve the above problems, a solar cell string according to an embodiment of the present invention includes the following components (A) to (E).
(A) A plurality of solar cell modules arranged in a line each having a positive electrode cable and a negative electrode cable are provided.
(B) a series circuit that electrically connects the positive electrode cable and the negative electrode cable of the solar cell modules that are located next to each other to electrically connect the solar cell modules in series;
(C) The arrangement direction of the solar cell modules is defined as the left-right direction, and each of the solar cell modules is a half-cell module, and each solar cell module has a positive side terminal box to which the positive electrode cable is connected and the negative electrode cable. The positive terminal box and the negative terminal box are arranged apart from each other in the left-right direction.
(D) By alternately arranging the solar cell modules adjacent to each other upside down, the positive electrode side terminal box and the negative electrode side terminal box are arranged on the left and right sides of the solar cell modules located one next next to each other. The solar cell modules are arranged in the same order in the direction.
(E) The solar cell modules located at adjacent positions are arranged such that the positive terminal box and the negative terminal box are arranged in reverse order in the left-right direction.

Further, a solar power generation system according to an embodiment of the present invention is characterized by including the solar cell string.

1 is a block diagram showing a solar power generation system according to an embodiment of the present invention. FIG. 3 is a rear view of a solar cell module according to another embodiment of the present invention. Schematic diagram showing a conventional solar power generation system. Schematic diagram showing a conventional solar power generation system.

(composition)
Embodiments of a solar cell string and a solar power generation system according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a solar power generation system according to an embodiment of the present invention. The solar power generation system 1 according to this embodiment employs a half cell module as the solar cell module 2. The solar cell module 2 has an upper half as cluster A and a lower half as cluster B.

As shown in FIG. 1, a solar power generation system 1 according to the present embodiment includes a solar cell string 3 having a plurality of solar cell modules 2 electrically connected in series, and a solar cell string 3 interconnected to a power grid 50. a power conditioner 6 that electrically connects the solar cell string 3 and the power conditioner 6, a connection box 7 that connects the output of the power conditioner 6 to the power grid 50, Equipped with The solar power generation system 1 includes a plurality of power conditioners 6, and a plurality of solar cell strings 3 are electrically connected in parallel to each power conditioner 6 to obtain a required power generation capacity.

The solar cell string 3 includes a plurality of (for example, six) solar cell modules 2 arranged in a line, and solar cell modules located next to each other (one next to each other or one place ahead). A series circuit 15 that electrically connects the two positive electrode cables 12 and negative electrode cables 13 to electrically connect the solar cell modules 2 in series is provided. The plurality of solar cell modules 2 are arranged in a straight line with the arrangement direction defined as the left-right direction. The six solar cell modules 2 are designated 2A, 2B, 2C, 2D, 2E, and 2F in order from the left side of FIG.

Each solar cell module 2 has a power generation capacity of several tens of W, and generates power by receiving light on its rectangular light receiving surface. The solar cell module 2 is a rectangular plate-like body having long sides and short sides, for example, a long side=approximately 1235 mm and a short side=approximately 641 mm. In each solar cell module 2, the direction in which the short sides extend is the left-right direction, and the direction in which the long sides perpendicular thereto extends is the up-down direction. Although the solar cell string 3 according to this embodiment has solar cell modules 2 arranged linearly in the short side direction, the solar cell modules 2 may be arranged linearly in the long side direction.

Each solar cell module 2 is connected to a positive terminal box 112 and a negative terminal box 113 located on the non-light receiving surface side, and to a positive cable 12 and a negative terminal box 113 connected to the positive terminal box 112. A negative electrode cable 13 (hereinafter also simply referred to as cables 12 and 13) is provided. The outer diameter dimensions of the terminal boxes 112 and 113 are set to be sufficiently small relative to the solar cell module 2.

In each solar cell module 2, the positive terminal box 112 and the negative terminal box 113 are arranged apart from each other in the left-right direction. In this embodiment, the positive terminal box 112 and the negative terminal box 113 are arranged at both ends of a line passing through the center of the long side of the solar cell module 2 in the left-right direction. That is, the positive terminal box 112 is located on the left edge of the solar cell module 2 , and the negative terminal box 113 is located on the right edge of the solar cell module 2 . At this time, if the vertical directions of the solar cell modules 2 are all the same, the terminal boxes 112 and 113 of different polarities will be close to each other.

However, in this embodiment, mutually adjacent solar cell modules 2 are alternately arranged upside down. In the example shown in FIG. 1, solar cell modules 2A, 2C, and 2E face upward with cluster A as the upper half, and solar cell modules 2B, 2D, and 2F face downward with cluster A as the lower half. That is, the solar cell modules 2 adjacent to each other are arranged rotated by 180 degrees, and the left and right positions of the terminal boxes 112 and 113 are swapped, so that the terminal boxes 112 and 113 of the same polarity are arranged close to each other. will be done.

Specifically, in the upward facing solar cell modules 2A, 2C, and 2E, the positive terminal box 112 is located on the left edge, and the negative terminal box 113 is located on the right edge. On the other hand, in the downward facing solar cell modules 2B, 2D, and 2F, the negative terminal box 113 is located on the left edge, and the positive terminal box 112 is located on the right edge.

In other words, in this embodiment, the solar cell modules 2 are arranged so that the positive terminal box 112 and the negative terminal box 113 are arranged in the same order in the left-right direction between the solar cell modules 2 located one position ahead of each other. ing. Specifically, in the solar cell modules 2A, 2C, and 2E, the positive terminal box 112 is on the left side, and the negative terminal box 113 is on the right side. On the contrary, in solar cell modules 2B, 2D, and 2F, the positive terminal box 112 is on the right side, and the negative terminal box 113 is on the left side.

An extension cable 4 is connected to the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2A. The negative cable 13 extending from the negative terminal box 113 of the solar cell module 2A and the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2C are connected by skipping the solar cell module 2B.

The negative cable 13 extending from the negative terminal box 113 of the solar cell module 2C and the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2E are connected by skipping the solar cell module 2D. The negative cable 13 extending from the negative terminal box 113 of the solar cell module 2E and the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2F are connected in an S-shape.

The negative cable 13 extending from the negative terminal box 113 of the solar cell module 2F and the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2D are connected by skipping the solar cell module 2E. Further, the negative cable 13 extending from the negative terminal box 113 of the solar cell module 2D and the positive cable 12 extending from the positive terminal box 112 of the solar cell module 2B are connected by skipping the solar cell module 2C. The negative electrode cable 13 extending from the negative electrode side terminal box 113 of the solar cell module 2B extends in a gentle S-shape, and the extension cable 5 is connected to the free end.

The power conditioner 6 includes an inverter (not shown) that converts the DC power output by the solar cell string 3 into AC power of a predetermined frequency (for example, commercial power supply frequency), and includes load equipment (not shown) connected to the AC system. , or connected in parallel to the power grid 50 to supply power.

In addition, since the output of the solar cell string 3 fluctuates depending on the solar radiation intensity and the surface temperature of the solar cell module 2, the power conditioner 6 changes the operation of the solar cell string 3 so as to follow the maximum output point. Maximum Power Point Tracking (MPPT) is performed to extract the maximum power of the battery string 3. Here, attention is paid to the power line 21 that connects the solar cell string 3 to the connection box 7. Power line 21 leads extension cables 4 and 5 to junction box 7.

(action and effect)
In the present embodiment having the above configuration, the positive terminal box 112 and the negative terminal box 113 in each solar cell module 2 are placed apart from each other in the left-right direction, and the solar cell modules 2 located one space ahead Now, the solar cell modules 2 are arranged so that the positive terminal box 112 and the negative terminal box 113 are arranged in the same order in the left-right direction.

According to this embodiment, since the positive electrode side terminal box 112 and the negative electrode side terminal box 113 are arranged in the same order in the left and right direction in the solar cell modules 2 located one next to each other, a half cell module is adopted. Even if the positive terminal box 112 and the negative terminal box 113 are placed apart in the left-right direction, the terminal boxes 112 and 113 with different polarities will be separated by a distance between the solar cell modules 2 located one step ahead of each other. can be approached. Therefore, in this embodiment, the cable length in which the positive electrode cable 12 and the negative electrode cable 13 are connected can be made close to the length of one solar cell module 2.

At this time, in this embodiment, since the positive terminal box 112 and the negative terminal box 113 are arranged at both ends of the line passing through the solar cell module 2 in the left-right direction, the positive terminal box 112 in each solar cell module 2 And the negative terminal box 113 is the farthest apart in the left-right direction in a horizontal state. Therefore, the positive electrode side terminal box 112 and the negative electrode side terminal box 113 of the solar cell modules 2 located one position ahead can be brought closest in the distance in the left-right direction. Specifically, the negative terminal box 113 of the solar cell module 2A, the positive terminal box 112 of the solar cell module 2C, the positive terminal box 112 of the solar cell module 2B, the negative terminal box 113 of the solar cell module 2D, and the solar cell. The negative terminal box 113 of the module 2C, the positive terminal box 112 of the solar cell module 2E, the positive terminal box 112 of the solar cell module 2D, and the negative terminal box 113 of the solar cell module 2F are located at the distance in the left-right direction, respectively. You can get close. As a result, the cable length of the cable connection body connecting the cables 12 and 13 can be shortened, and the cable length of the cables 12 and 13 themselves can also be shortened. This makes it possible to suppress an increase in power loss and reduce costs.

In particular, in a photovoltaic power generation system 1 equipped with a large number of solar cell strings 3 such as a mega solar system, it is effective to eliminate power loss caused by long cable lengths. It is possible to further improve the efficiency of the power generation system 1 and the solar cell string 3. Furthermore, in this embodiment, it is possible to reduce costs by shortening the cable length, which also contributes to cost reduction of the solar power generation system 1 and the solar cell string 3.

In addition, in this embodiment, by simply arranging the solar cell modules 2 adjacent to each other upside down alternately, the solar cell modules 2 located one position ahead can connect the positive terminal box 112 and the negative terminal box. The solar cell modules 2 can be arranged so that the boxes 113 are arranged in the same order in the left and right direction. Therefore, it is possible to arrange the solar cell modules 2 in a desired manner with a simple operation, and the operation cost is reduced. Furthermore, since no changes are made to the configuration of the solar cell module 2 itself, there is no need to worry about cost increases from the viewpoint of manufacturing costs.

Furthermore, in this embodiment, the positive terminal box 112 and the negative terminal box 113 are arranged at both ends of a line passing through the center of the solar cell module 2 in the left-right direction, so the solar cell module 2 is alternately oriented upside down. When the terminal boxes 112 and 113 are arranged horizontally, the horizontal positions of the positive terminal box 112 and the negative terminal box 113 do not shift. Therefore, the cable length of the cable connection body in which the positive electrode cable 12 and the negative electrode cable 13 are connected can be minimized. Furthermore, since the cable lengths of the cable connection bodies can be made the same, standardization of the cables 12 and 13 is easy, which is also economically advantageous.

(Other embodiments)
Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

For example, as shown in FIG. 2, a rating nameplate 16 may be attached to the solar cell module 2. According to this embodiment, the vertical orientation of the solar cell module can be accurately grasped using the position and description of the rating nameplate 16 as a guide. Therefore, it is easy to arrange the solar cell modules 2 so that the terminal boxes 112 and 113 of the same polarity are close to each other, and the cable lengths of the positive electrode cable 12 and the negative electrode cable 13 can be reliably shortened to efficiently reduce power loss. It is possible to suppress it well.

Furthermore, as shown in FIG. 2, D/W≧0.1, where D is the horizontal distance between the positive terminal box 112 and the negative terminal box 113, and W is the horizontal dimension of the solar cell module 2. It also includes embodiments. In such an embodiment, the distance in the left-right direction between the positive terminal box 112 and the negative terminal box 113 is one-tenth of the width of the solar cell module 2; This can be effective in shortening the cable length.

In addition, as shown in FIG. 2, the distance between the positive terminal box 112 and the negative terminal box 113 in the left-right direction is D, the horizontal dimension of the solar cell module 2 is W, and the gap between the solar cell modules 2 is d. do. Further, if the remaining length of the cable is le, and the cable length of the cable connection body of the positive electrode cable 12 and negative electrode cable 13 when one solar cell module 2 is skipped is 2Lm,
Lm=(WD)/2+d+W/2+le
The formula holds true. Here, by setting Lm to be the minimum, the cable lengths of the positive electrode cable 12 and the negative electrode cable 13 can be easily shortened.

Further, the positive terminal box 112 and the negative terminal box 113 may be placed apart in the left-right direction, and may not be placed at both ends of a line passing through the center of the solar cell module 2 in the left-right direction. Good too. For example, the positive terminal box 112 and the negative terminal box 113 may be arranged at both ends of a horizontal line shifted in either the up or down direction from the center of the solar cell module 2.

In such an embodiment, when mutually adjacent solar cell modules 2 are alternately arranged upside down, the positions of the positive terminal box 112 and the negative terminal box 113 are shifted in the vertical direction for each solar cell module 2. Therefore, the status of the solar cell module 2 can be checked immediately. Moreover, when performing the connection work of connecting the cables 12 and 13, the positive terminal box 112 and the negative terminal box 113 do not get in the way of the work. Therefore, workability is improved and costs can be further reduced.

Further, even in a solar power generation system in which an AC current collection box is installed between the PCS 6 and the transformer 8 instead of the connection box 7 in FIG. 1, the same effects as in each embodiment can be achieved.

1... Solar power generation system 2... Solar cell module 3... Solar cell strings 4, 5... Extension cable 6... Power conditioner 7... Connection box 8... Grid connection transformer 11... Terminal box 12... Positive electrode cable 13... Negative electrode cable 15...Series circuit 16...Rating nameplate 21...Power line 50...Power system

Claims (5)

solar cell modules each having a positive electrode cable and a negative electrode cable and arranged in a linear manner;
a series circuit that electrically connects the positive electrode cable and the negative electrode cable of the solar cell modules located next to each other to electrically connect the solar cell modules in series;
The arrangement direction of the solar cell modules is defined as the left-right direction, and each of the solar cell modules is a half-cell module, and for each solar cell module, the negative electrode cable is connected to a positive terminal box to which the positive electrode cable is connected. having only one pair of negative terminal boxes, and arranging the positive terminal box and the negative terminal box apart in the left-right direction;
By alternately arranging the solar cell modules adjacent to each other upside down, the positive terminal box and the negative terminal box are the same in the left-right direction in the solar cell modules located one next next to each other. In order of placement,
The solar cell string is characterized in that the solar cell modules are arranged such that, for the solar cell modules located at adjacent positions, the positive terminal box and the negative terminal box are arranged in reverse order in the left-right direction. The solar cell string according to claim 1, wherein the positive terminal box and the negative terminal box are arranged at both ends of a line passing through the solar cell module in the left-right direction. 3. The solar cell string according to claim 1, wherein the solar cell module has a rating plate attached thereto. D/W≧0.1, where D is the distance between the positive terminal box and the negative terminal box in the horizontal direction, and W is the horizontal dimension of the solar cell module. 3. The solar cell string according to any one of 3. A solar power generation system comprising the solar cell string according to any one of claims 1 to 4.

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