JP2865482B2 - Output terminal box for solar cell module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output terminal box for a photovoltaic module including a plurality of photovoltaic cells electrically connected in series or in parallel, and more particularly, to an output terminal box for a photovoltaic cell having at least one output current. The present invention relates to an output terminal box provided with at least one of a bypass diode that can be bypassed without passing through the cell and a backflow prevention diode that can prevent a reverse current from passing through the solar cell.

[0002]

2. Description of the Related Art An example of a conventional solar cell module is illustrated with reference to FIG. FIGS. 3A, 3B and 3C are top views of the solar cell module, respectively.
It shows a vertical sectional view and an equivalent circuit diagram. Generally, the solar cell module 1A includes a plurality of solar cells 2 electrically connected in series by an interconnector 3 so as to obtain a desired output voltage. However, in the solar cell module 1A having the structure in which the plurality of solar cells 2 are connected in series, one solar cell 2 in the module is shaded, but the other cells 2 are shaded. However, the solar cell module 1A is greatly affected by the single cell 2 in the shadow, and the output of the entire module 1A is greatly reduced.

Referring to FIG. 4, the output voltage-current (VI) characteristic of one solar cell 2 is shown. In the graph of FIG. 4, the horizontal axis represents the voltage V, and the vertical axis represents the current I. FIG. 4A shows the VI characteristics when one entire solar cell 2 is irradiated with light.
FIG. 4B shows the VI characteristics when about half of one solar cell 2 is shaded. FIG. 4 (A) and (B)
As can be seen from the comparison, the output current I of the half-shaded solar cell 2 is reduced to about half that of the cell 2 which is entirely irradiated with light.

FIG. 5 is similar to FIG. 4, but shows the VI characteristics of one solar cell module 1A as a whole.
Here, FIG. 5A shows the VI characteristics when all the solar cells 2 in the module 1A are receiving light irradiation, while FIG. 5B shows the VI characteristics in the module 1A.
V when about half of the two solar cells 2 are shaded
-I characteristic. As can be seen from the comparison between FIGS. 5A and 5B, even when about half of the single solar cell 2 in the module 1A is shaded, the output current I of the entire solar cell module 1A is about It is affected by being reduced by half.

Referring to FIG. 6, there is schematically shown an example of a solar cell system in which a plurality of solar cell modules 1A are further connected in series. FIGS. 6 (A) and (B)
They respectively show a block diagram and an equivalent circuit diagram of the solar cell system. Even in such a solar cell system, even when only one of the solar cells is shaded, the output is reduced as shown in FIG. 5B.

In the above-described solar cell module and solar cell system, a large reverse bias voltage is applied to a shadowed solar cell depending on an external circuit to which the cell is connected, and the cell is destroyed. Sometimes. In extreme cases, the reverse bias overheats the solar cells and may cause a fire in the case of a solar cell module installed on a roof.

[0007] In order to improve the above-described problems of the output reduction of the solar cell module and the breakage of the cell, a solar cell module provided with a bypass diode is known in the prior art.

Referring to FIG. 7, an example of one solar cell module having one bypass diode is illustrated. FIGS. 7A, 7B, and 7C show a top view, a longitudinal sectional view, and an equivalent circuit diagram of the solar cell module 1C, respectively. A solar cell module 1C including a desired number of solar cells 2 connected in series includes one bypass diode 4 connected in parallel with the opposite polarity. This bypass diode 4 does not reduce a decrease in the output of the entire module 1C when some of the solar cells 2 in the solar cell module 1C are shaded, but a reverse bias voltage acts on the module 1C. Sometimes it can act to protect the entire module 1C from damage due to reverse bias voltage.

Referring to FIG. 8, a solar cell system having one bypass diode for each solar cell module is schematically illustrated. FIGS. 8A and 8B
Shows a block diagram and an equivalent circuit diagram of the solar cell system, respectively. This solar cell system includes a plurality of solar cell modules 1C connected in series,
Each solar cell module 1C includes one bypass diode 4. These bypass diodes 4 can act to reduce a decrease in the output of the entire solar cell system even when some of the solar cells 2 in the solar cell module 1C are shaded.

FIG. 9A shows the solar cell module 1 shown in FIG.
FIG. 9B shows the V-1 characteristic when all the solar cells in C are receiving light irradiation. In FIG. 9B, about half of one solar cell in module 1C is shaded. The V-1 characteristic when the power is on. FIG. 9C shows the V-1 characteristic when no bypass diode is provided. FIG.
As can be seen from a comparison between (B) and FIG. 9 (C), the bypass diode 4 reduces the output of the entire module 1C when some of the solar cells in the solar cell module 1C are shaded. It can act to minimize.

Referring to FIG. 10A, an example of a solar cell system in which a plurality of solar cell modules 1 are connected in parallel to obtain a desired output current is schematically shown.
In this figure, arrows indicate the direction of the photovoltaic current. When light is applied to all the solar cell modules 1 in the solar cell system of FIG.
Normal output current (I) and output voltage (V) as shown in the graph of 0 (B) are obtained.

Referring to FIG. 11A, a case where one solar cell module 1 in the solar cell system of FIG. 10A is shaded is illustrated. Is shaded by hatching. As indicated by the arrow in the figure, a reverse current supplied by the photovoltaic power of another solar cell module 1 flows through the solar cell module 1 which is shaded. Therefore, in the state of FIG. 11A, the output current of the solar cell system is greatly reduced as shown in the graph of FIG. 11B.

Referring to FIG. 12A, there is shown a solar cell system having a backflow prevention diode. In this solar cell system, a backflow prevention diode 8 is connected in series to each of the solar cell modules 1 connected in parallel with each other. Therefore, even if one solar cell module 1 in the solar cell system of FIG. 12A is shaded, as shown in the graph of FIG.
The decrease in the output current (I) is reduced as compared with FIG. That is, the backflow prevention diode 8 prevents the reverse current from flowing into the shaded solar cell module 1.

The above-mentioned bypass diode 4 and backflow prevention diode 8 can be connected in a terminal box as shown in FIG. FIG. 13A is a plan view of the terminal box, in which most of the terminal box housing included therein is removed. FIG. 13B is a cross-sectional view taken along line 13B-13B in FIG. In these figures, the terminal box housing 18
Is fixed on the solar cell module body 1. In the terminal box housing, the relay terminal support plate 13 is fixed by a relay terminal support plate stopper 22 and a rib 21.
A relay frame 12 having a hole 14 is fixed on the relay terminal support plate 13. The relay frame 12 is connected to the output extraction conductor 11 through the hole 10. The holes 14 in the relay frame 12 allow the output leads 15 to pass through. The bypass diode 4 is connected between the two output leads 15 in parallel with the solar cell module 1. On the other hand,
The backflow prevention diode 8 is connected in series between one output extraction conductor 11 and one output lead wire 15.

[0015]

Conventionally, the bypass diode and the backflow prevention diode described above have a cylindrical shape as shown in FIG. 13, and have a relatively large thickness. Therefore, there is a problem that the terminal box for housing these diodes is thick and bulky. There is also a problem that the connection inside the terminal box is complicated.

Accordingly, one object of the present invention is to provide a terminal box for a solar cell module, which includes a bypass diode and a backflow prevention diode, and is thin and miniaturized. .

Another object of the present invention is to provide a terminal box for a solar cell module in which electrical connection of a bypass diode and a backflow prevention diode is easy and stable.

[0018]

Means for Solving the Problems The solar cell module terminal box of the present invention, the relay terminal support plate provided in the housing of the terminal box, substantially electrically conductive connection provided in the center portion of the support plate and parts, comprising at least one of the connecting portion to the joined pair <br/> let like bypass diodes and pellets of the backflow prevention diode, the conductive contact
The connecting part has an area larger than the junction surface of the diode pellet.
The bypass diode is electrically connected to release a reverse bias voltage applied to the shaded solar cell when at least some of the solar cells in the solar cell module are shaded. The backflow prevention diode is electrically connected so as to prevent a current in a direction opposite to the photovoltaic current in the shaded solar cell module from flowing.

[0019]

In the terminal box for a solar cell module according to the present invention, since a small and thin pellet-shaped diode is used as the bypass diode and the backflow prevention diode, the terminal box can be made thin and small. In addition, these pellet-shaped diodes are provided almost at the center of the relay terminal support plate without the use of interconnectors or lead wires.
The terminal box for a solar cell module can be easily and reliably assembled because it can be soldered directly on the conductive connection having a large area .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1A to 1C, a step of connecting a bypass diode in a solar cell module terminal box according to an embodiment of the present invention is illustrated in a plan view. (D) is a line 1D- in FIG. 1 (C).
It is sectional drawing along ID.

In FIG. 1A, two conductive relay terminal connection portions 13a are provided on an insulating relay terminal support plate 13.
Is provided. A pellet-shaped bypass diode 4a is fixed on one relay terminal connection portion 13a by soldering or the like.

In FIG. 1B, an interconnector 2
5 or one end of the lead wire 25 is a bypass diode 4a.
And the other end is connected to another relay terminal connection portion 13a on the relay terminal support plate.

In FIG. 1C, a relay frame 12 and an output lead 15 are connected to each of the two relay terminal connection portions 13a. Thereby, the bypass diode 4a is connected between the two output leads 15 in parallel with the solar cell module.

As can be seen from the sectional view of FIG. 1D, the conductive relay terminal connecting portion 13a is provided on the relay terminal support plate 13.
, On which a small and thin pellet-shaped bypass diode 4a is laminated and connected. And
An interconnector 25 or a lead wire 25 is connected to the bypass diode 4a. That is, FIG.
The interconnection in the relay terminal connection structure as shown in (C) is simple and reliable, and the connection structure can be housed in a small and thin terminal box housing.

Referring to FIGS. 2A and 2B, there is shown in a plan view a step of connecting a backflow prevention diode in a solar cell module terminal box according to another embodiment of the present invention.

In FIG. 2A, two conductive relay terminal connecting portions 13a are placed on an insulating relay terminal support plate 13.
Is provided. A small and thin pellet-shaped backflow prevention diode 8a is fixed on one relay terminal connection portion 13a by soldering or the like.

In FIG. 2B, a relay frame 12 is connected on the backflow prevention diode 8a, and a relay terminal connection portion 13a to which the backflow prevention diode 8a is joined.
The output lead wire 15 is connected to the other area. further,
Another relay frame 12 and an output lead 15 are connected to another relay terminal connection portion 13a. Thereby, the backflow prevention diode 8a is connected in series with the solar cell module. Similar to the connection structure including the bypass diode 4a shown in FIG. 1, the relay terminal connection structure including such a backflow prevention diode has a simple and reliable interconnection, and is further provided in a small and thin terminal box housing. It will be appreciated that it can be stored.

In addition to the above embodiment, various patterns of the relay terminal end can be considered depending on the connection method (such as mounting a backflow prevention diode and a bypass diode).

[0029]

As described above, in the terminal box for a solar cell module according to the present invention, since a small and thin pellet-shaped diode is used as the bypass diode and the backflow prevention diode, the terminal box can be made thin and small. In addition, these pellet-shaped diodes are electrically conductive contacts having a large area provided substantially at the center of the relay terminal support plate without through an interconnector or a lead wire.
Since it can be soldered directly on the connecting portion , the assembly of the terminal box for the solar cell module can be performed easily and reliably.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a connection structure in a terminal box for a solar cell module according to an embodiment of the present invention.

FIG. 2 is a view schematically showing a connection structure in a terminal box for a solar cell module according to another embodiment of the present invention.

FIG. 3 is a diagram showing an example of a conventional solar cell module.

FIG. 4 is an output voltage / current (VI) of one solar cell
It is a figure showing a characteristic.

FIG. 5 is a diagram showing VI characteristics of one solar cell module as a whole.

FIG. 6 is a diagram illustrating an example of a conventional solar cell system including a plurality of solar cell modules.

FIG. 7 shows an example of a prior art solar cell module with only one bypass diode.

FIG. 8 shows a prior art solar cell system with one bypass diode for each solar cell module.

FIG. 9 shows V in a solar cell module according to the prior art.
It is a figure which shows -I characteristic.

FIG. 10 is a diagram showing a solar cell system in which a plurality of solar cell modules are connected in parallel and their VI characteristics.

11 shows a case where one solar cell module in the solar cell system of FIG. 12 is shaded and VI in that case.
It is a figure showing a characteristic.

FIG. 12 is a diagram showing a conventional solar cell system in which a plurality of solar cell modules having a backflow prevention diode connected in series are connected in parallel to each other, and their VI characteristics.

FIG. 13 is a view showing a conventional terminal box for a solar cell module.

[Explanation of symbols]

1, 1A, 1B, 1C Solar cell module 2 Solar cell 3 Interconnector for connecting solar cells in series 4 Bypass diode according to prior art 4a Pellet-shaped bypass used in terminal box for solar cell module of the present invention Diode 8 Conventional backflow prevention diode 8a Pellet-shaped backflow prevention diode used in the solar cell module terminal box of the present invention 10 Hole 11 Output conductor 12 Relay frame 13 Relay terminal support plate 13a Relay terminal connection portion 14 Relay frame hole 15 Output lead wire 18 Terminal box housing 21 Rib 22 Stopper for relay terminal support plate

Claims (1)

(57) [Claims] 1. A output terminal box for a solar cell module, a relay terminal support plate provided in the housing of the box, a conductive connecting portion provided in the substantially central portion of the support plate, the conductive And at least one of a pellet-shaped bypass diode and a pellet-shaped backflow prevention diode joined to the conductive connection portion , wherein the conductive connection portion has a surface larger than a joining surface of the pellet.
Product, the bypass diode, when at least some of the solar cells in the solar cell module is shaded,
Electrically connected to release a reverse bias voltage applied to the shaded solar cell module, wherein the backflow prevention diode is opposite to a photovoltaic current in the shaded solar cell module. An output terminal box for a solar cell module, wherein the output terminal box is electrically connected so as to prevent a current in a direction from flowing.