JP5705023B2 - Connection box for photovoltaic power generation - Google Patents

Description

  The present invention relates to a junction box that collects power generated by a solar cell and sends it to a power conditioner in a solar power generation system.

In the photovoltaic power generation system, power is generated by a plurality of solar battery panels, and the generated DC power is collected into one circuit output in a junction box and sent to a power conditioner. Then, it is converted into AC power that can be used at home in the power conditioner.
The connection box used in this way is installed outdoors, incorporating a switch, a backflow prevention diode, a surge absorber, a terminal block for connecting to the introduced cable, and the like (see, for example, Patent Document 1).

JP 2000-261177 A

Among the devices and members incorporated in the junction box, the backflow prevention diode is accompanied by a large amount of heat. Therefore, it is attached to the heat sink and incorporated into the case. However, since the case is installed outdoors, it is installed in a sealed environment, and the temperature is likely to rise, and a large heat sink is used to suppress the temperature rise within a predetermined range. As a result, the entire junction box was large.
In addition, in the junction box disclosed in Patent Document 1, an increase in the case can be suppressed by providing a heat-dissipating hole in the upper part of the case to suppress the temperature rise. The structure of the case has become complicated for the installation structure.

  For this reason, if the case itself is made to function as a heat sink, the temperature rise can be suppressed even if the heat sink is made small, which can contribute to the miniaturization of the case. However, maintaining the high airtightness of the junction box and heat dissipation It has been difficult to achieve a mounting form in which the plate is closely attached to the case by screwing or the like.

  Therefore, in view of such problems, the present invention provides a junction box for photovoltaic power generation that realizes the airtightness of the junction box case and the configuration that effectively radiates heat through the case with a simple configuration. It is an object.

In order to solve the above problems, the invention of claim 1 is a connection box for photovoltaic power generation in which a backflow prevention diode, a DC switch, etc. are incorporated in a case, and on the case back plate in the case, The female screw body for screwing the substrate on which the switch is assembled is formed with a protrusion, and has a flat portion that closely contacts the heat radiating plate to which the backflow prevention diode is assembled, and the heat radiating plate has the female screw A plurality of engaging portions that engage with the body, a flat back surface in a state in which the backflow prevention diode is assembled, and a board mounted on a case back plate via the female screw body and the female screw body In an engaged state, there is an overlapping area with the heat radiating plate disposed on the flat portion, and a pressing portion for pressing the heat radiating plate against the case back plate is formed at an appropriate portion of the overlapping area of the substrate. The substrate By screwing to the threaded body, wherein the heat radiating plate is brought into close contact with the case back plate.
According to this configuration, since the heat sink is brought into close contact with the back surface of the junction box by screwing the substrate, the heat sink can be brought into close contact with the case with a simple configuration without performing a separate operation such as screwing. . As a result, even if the case has a hermetically sealed structure, the backflow prevention diode can be radiated well, which contributes to the miniaturization of the heat radiating plate and the miniaturization of the junction box.

According to a second aspect of the present invention, in the configuration according to the first aspect, the pressing portion is formed of a tongue piece formed by bending the substrate backward at a substantially right angle.
According to this configuration, since the substrate is pressed by the tongue piece bent rearward, a space can be provided between the substrate and the heat radiating plate, and even if an overlapping area is provided, the heat radiating action of the heat radiating plate is not hindered. .

According to a third aspect of the present invention, in the configuration according to the first or second aspect, the engaging portion provided in the heat radiating plate is a hole through which the female screw body is inserted and engaged. .
According to this configuration, the heat radiating plate can be reliably positioned on the flat portion, and no deviation occurs. Therefore, it can be made to adhere by a simple operation without using fixing means such as screws.

  According to the present invention, since the heat sink having a flat back surface is in close contact with the back surface of the connection box by screwing the substrate, it can be in close contact with a simple configuration without being screwed separately. Therefore, it is possible to effectively dissipate the backflow prevention diode while maintaining the airtightness of the junction box case.

It is a perspective view which shows an example of the connection box for solar power generation concerning this invention, and has shown the state which removed the door. It is a front view of FIG. It is XX sectional drawing, (a) is a cross section of the whole box, (b) is an enlarged view of the A section. It is a YY line sectional view, (a) is a section of the whole box, (b) is an enlarged view of the B section.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the drawings. 1 and 2 are explanatory views showing an example of a connection box for photovoltaic power generation according to the present invention, FIG. 1 is a perspective view, and FIG. 2 is a front view. Each shows a state in which the door that closes the front surface of the junction box case 10 is removed, 1 is a DC switch, 2 is a backflow prevention diode, 3 is a terminal block, 4 is a substrate, and 5 is a heat sink. The DC switch 1 and the terminal block 2 are assembled to the substrate 4 with screws, and the backflow prevention diode 2 is assembled to the heat sink 5 with screws. The case 10 forms a sealed junction box by closing the front face with a door (not shown).

  The DC switch 1 is installed to disconnect the photovoltaic power generator from the electrical circuit during the maintenance of the photovoltaic power generator or the electrical circuit, and the backflow prevention diode 2 prevents the power from flowing back when the power is not generated at night or the like. To be provided.

3 shows a cross section taken along line XX in FIG. 2, and FIG. 4 shows a cross section taken along line YY. As shown in FIG. 2, the heat sink 5 is disposed on a flat portion on the back plate 10a in the case 10, while the substrate 4 is provided with a certain gap from the back plate 10a as shown in FIGS. The substrate 4 and the heat sink 5 overlap each other and have an area W.
Specifically, the backflow prevention diode 2 is screwed to the heat radiating plate 5 with screws 6, but the heat radiating plate 5 is formed to be relatively thick, for example, an aluminum plate having a thickness of 3.0 mm and a flat back surface. used. A screw 6 is screwed to fix the backflow prevention diode 2 to the heat sink 5, but a screw 6 whose tip does not protrude from the back surface of the heat sink 5 is selected. As a result, even after the backflow prevention diode 2 is assembled, the heat sink 5 is maintained in a flat state on the back surface.

  The entire area of the back plate 10a is flat, and a female screw body 7 for mounting the substrate 4 is provided by welding. The female screw body 7 is a cylindrical body provided with a screw hole for screwing the screw 8 in the center, and a plurality of female screw bodies 7 are provided in accordance with the screwing portions 4a provided in the substrate 4. In this embodiment, the female screw body 7 is provided at four locations. Is formed.

  Of the female screw bodies 7 formed at four places, the upper two places are provided in the mounting area of the heat sink 5, and the female screw bodies are provided at two places corresponding to the female screw bodies 7 of the heat sink 5. A hole 12 (shown in FIG. 3) for inserting 7 is formed. The heat radiating plate 5 is positioned by inserting the female screw body 7 through the hole 12, and is closely attached to the back plate 10a by being pressed by the tongue piece 11.

  Note that the back plate 10a of the case 10 only needs to have a flat area where the heat sink 5 is mounted, and other portions may be provided with irregularities. In addition to the back surface, the heat sink 5 has a flat surface on which the backflow prevention diode 2 is assembled. However, on the front side, heat radiation fins may be provided at appropriate positions.

On the other hand, the substrate 4 has through holes as screwing portions 4a at appropriate portions (here, four locations), and the upper end, which is the portion that forms the overlapping portion W, is bent substantially at a right angle to the rear, and has a uniform depth. A tongue piece 11 is formed. The tongue piece 11 is formed with a depth in consideration of the height of the female screw body 7 and the thickness of the heat radiating plate 5, and a plurality of tongue pieces 11 are pressed so as to press the heat radiating plate 5 at a plurality of upper, lower, left and right portions of the upper two screwing portions 4 a. Has been placed.
And when the board | substrate 4 is mounted in the case 10 with the screw 8 in the state which engaged the internal heat sink 7 with the heat sink 7, and the tongue piece 11 presses the heat sink 5 against the back board 10a. To do.

As described above, the heat sink 5 is brought into close contact with the back surface of the connection box case 10 by the screwing operation of the substrate 4. Therefore, the heat sink is brought into close contact with the case 10 with a simple configuration without performing another close operation such as screwing. be able to. As a result, even if the case 10 has a hermetically sealed structure, the backflow prevention diode 2 can be radiated favorably, contributing to the miniaturization of the heat radiating plate 5 and the miniaturization of the junction box.
Moreover, since the heat sink 5 is pressed by the tongue 11 provided on the substrate 4, a space can be provided between the substrate 4 and the heat sink 5, and even if an overlap area is provided, the heat dissipation action of the heat sink 4 is hindered. There is nothing that can be done.
Furthermore, the heat radiating plate 5 is positioned by the female screw body 7 and is prevented from being displaced by being inserted into the hole 12, so that the positional displacement does not occur even if a separate fixing means is not used.

In the above embodiment, the hole 12 is provided in the heat radiating plate 5 and the female screw body 7 on the back plate is inserted for positioning. However, the heat radiating plate 5 is provided with a U-shaped notch, for example. It may be engaged with the female screw body 7.
Moreover, although the upper part of the board | substrate 4 is piled up with the lower part of the heat sink 5, the upper-lower positional relationship may be reversed and you may pile up side by side. Furthermore, you may arrange | position so that the board | substrate 4 may cover the heat sink 5 whole. Even if they are completely overlapped, it is possible to radiate heat well by providing a space between the substrate 4 and the heat radiating plate 5 as described above. And by extending the overlapping range, the internal space of the case 10 can be used more effectively, and the junction box can be further downsized.

  1 .... DC switch, 2 .... Backflow prevention diode, 3 .... Terminal block, 4 .... Board, 5 .... Heat sink, 10 .... Connection box case, 10a ..., Back plate, ... Pressing part), 12 .... hole (engaging part), W ... overlapping area.

Claims (3)

A junction box for photovoltaic power generation in which a backflow prevention diode, a DC switch, etc. are incorporated in a case,
On the case back plate in the case, a female screw body for screwing the board on which the switch is assembled is formed as a protrusion, and a flat portion is provided to closely contact the heat radiating plate assembled with the backflow prevention diode. And
The heat radiating plate has a plurality of engaging portions that engage with the female screw body, and includes a flat back surface in a state where the backflow prevention diode is assembled.
The board mounted on the case back plate via the female screw body and the heat dissipating plate disposed on the flat portion in a state of being engaged with the female screw body have an overlapping area,
A pressing portion for pressing the heat radiating plate to the case back plate is formed at an appropriate portion of the overlapping area of the substrate,
The solar power generation junction box, wherein the heat sink is brought into close contact with the case back plate by screwing the substrate to the female screw body. 2. The connection box for photovoltaic power generation according to claim 1, wherein the pressing portion is formed of a tongue piece formed by bending the substrate backward at a substantially right angle. 3. The connection box for photovoltaic power generation according to claim 1, wherein the engaging portion provided in the heat radiating plate is a hole through which the female screw body is inserted and engaged.

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