JP2012244066A - Solar cell connecting box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solar cell connecting box which can suppress a temperature rise in a top plate of a case that might be touched by a person, while performing radiation of equipment housed in the case.SOLUTION: The solar cell connecting box includes: a rectangular parallelepiped case 11 whose front surface is opened; a heat sink 13 having an attachment part 13b attached toward a bottom plate 11d of a back plate 11b of the case 11, and an uplift part 13a which is disposed toward a ceiling plate 11a of the case 11, and is lifted up from the back plate 11b; a switch 15 which is attached to the attachment part 13b of the heat sink 13, and is connected to a solar cell located outside the case 11; and a backflow prevention diode 16 which is attached to the uplift part 13a of the heat sink 13, and is connected between the switch 15 and an external power conditioner.

Description

  The present invention relates to a solar cell connection box that connects a solar cell and a power conditioner and separates the solar cell from a solar power generation system during maintenance and inspection of the solar cell.

  Conventionally, a plurality of switches for disconnecting a solar cell from a circuit when performing maintenance and inspection of the solar cell, a plurality of backflow prevention diodes for preventing a current from flowing from a high voltage solar cell to a low voltage solar cell, and the solar cell A solar cell junction box is disclosed in which a heat sink equipped with a plurality of surge absorbers that protects against surge voltages such as lightning and a terminal block is attached with screws so as to be in full contact with the back plate ( For example, see Patent Document 1).

JP 2000-173376 (paragraph 0003, FIG. 6)

  However, according to the above-described conventional technology, the heat radiating plate for radiating the heat of the backflow prevention diode is attached by screws so as to be in full contact with the back plate, and radiates heat from the surface of the solar cell junction box to the outside air. It has become. Therefore, there is a problem that the surface temperature of the solar cell junction box rises and becomes so hot that a person cannot touch it.

  The present invention has been made in view of the above, and is a solar cell junction box capable of suppressing a temperature rise of a top plate of a case that may be touched by a person while dissipating heat from a device built in the case. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, the present invention has a rectangular parallelepiped case whose front surface is opened, a mounting portion attached to the bottom plate of the back plate of the case, and a top plate of the case. And a heat sink that has a floating portion that floats from the back plate, a switch that is attached to the heat sink and is connected to a solar cell outside the case, and is attached to the lift portion of the heat sink And a backflow prevention diode connected between the switch and an external power conditioner.

  According to the present invention, the heat conduction distance from the backflow prevention diode, which is the main heat generation source, to the top plate of the case is increased, and an increase in temperature of the top plate of the case can be suppressed.

FIG. 1-1 is an exploded perspective view showing Embodiment 1 of a solar cell junction box according to the present invention. 1-2 is a front view of a state where a cover of the solar cell junction box of Embodiment 1 is removed. FIG. 1-3 is sectional drawing of the state which removed the cover of the solar cell connection box of Embodiment 1. FIGS. FIGS. 1-4 is a circuit diagram of the photovoltaic power generation system to which the solar cell connection box of the first embodiment is connected. 1-5 is a rear perspective view showing a temperature rise during power generation of the solar cell junction box of the first embodiment. FIG. 1-6 is a rear perspective view showing a temperature rise during power generation of a conventional solar cell junction box shown as a comparative example. FIG. 2-1 is an exploded perspective view showing Embodiment 2 of the solar cell junction box according to the present invention. FIG. 2-2 is a front view of a state in which the cover of the solar cell junction box of the second embodiment is removed. FIGS. 2-3 is sectional drawing of the state which removed the cover of the solar cell junction box of Embodiment 2. FIGS. FIG. 3-1 is an exploded perspective view showing Embodiment 3 of the solar cell junction box according to the present invention. FIG. 3-2 is a front view of a state in which the cover of the solar cell junction box of the third embodiment is removed. FIG. 3-3 is a cross-sectional view of the state in which the cover of the positive battery connection box of the third embodiment is removed.

  Embodiments of a solar cell connection box according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1-1 is an exploded perspective view showing Embodiment 1 of the solar cell connection box according to the present invention, and FIG. 1-2 is a front view of the solar cell connection box according to Embodiment 1 with the cover removed. FIG. 1-3 is a cross-sectional view of the solar cell connection box of the first embodiment with the cover removed, and FIGS. 1-4 show the connection of the solar cell connection box of the first embodiment. It is a circuit diagram of a photovoltaic power generation system.

  As shown in FIGS. 1-1 to 1-3, the solar cell connection box 10 of the first embodiment includes a rectangular parallelepiped box-shaped case 11 whose front surface is released, a cover 12 that covers the front surface of the case 11, and an intermediate It has a raised portion 13a that is bent and inclined by approximately 15 ° at the bending line of the portion so as not to come into contact with the back plate 11b of the case 11, and the attachment portion 13b is attached to the back plate 11b of the case 11 by screws 14. And a heat radiating plate 13. The raised portion 13a of the heat radiating plate 13 is disposed near the top plate 11a of the case 11, and the attachment portion 13b is disposed near the bottom plate 11d. The raised portion 13 a of the heat radiating plate 13 is inclined with respect to the back plate 11 b of the case 11. The case 11, the cover 12, and the heat radiating plate 13 are formed by bending a metal plate by press molding.

  Four (a plurality of) switches 15 are mounted in the horizontal direction on the mounting portion 13 b of the heat radiating plate 13, and a terminal block 17 is mounted next to the switch 15. Further, four (a plurality) of backflow prevention diodes 16 that generate heat are arranged side by side in the horizontal direction on the floating portion 13a of the heat sink 13.

  As shown in FIG. 1-4, the solar cell connection box 10 connects the solar cell 50 of the photovoltaic power generation system 90 and a power conditioner 60 that converts DC power generated by the solar cell 50 into AC power. When performing maintenance and inspection of the battery 50, the switch 15 is opened and the solar battery 50 is disconnected from the power conditioner 60.

  As shown in FIG. 1-4, the (+) side and the (−) side of the four sets of solar cells 50 in which one set of four solar cells 50 are connected in series are respectively four switches 15. Connected to the input terminal. The backflow prevention diodes 16 that generate heat are connected to the output terminals on the (+) side of the four switches 15, and the same (+) input of the terminal block 17 is connected to the output side of each of the backflow prevention diodes 16. The (+) output terminal of the terminal block 17 is connected to the (+) side of the power conditioner 60. The backflow prevention diode 16 prevents current from flowing from the high voltage solar cell 50 to the low voltage solar cell 50.

  The output terminals on the (−) side of the four switches 15 are connected to the same (−) input terminal of the terminal block 17, and the (−) output terminal of the terminal block 17 is the (−) of the power conditioner 60. Connected to the side. The (+) output terminal and the (−) output terminal of each of the four switches 15 are connected by a surge absorber 19 that protects the solar cell 50 from a surge voltage such as lightning (the surge absorber 19 is illustrated in FIG. 1-1 to FIG. 1-3).

  As illustrated in FIG. 1B, the devices in the case 11 are connected to each other by a wiring 18. The wiring connection between the solar cell 50 and the switch 15 and the wiring connection between the terminal block 17 and the power conditioner 60 are performed through a wiring hole 11c provided in the bottom plate 11d of the case 11 shown in FIG.

  According to the solar cell junction box 10 of the first embodiment described above, the backflow prevention diode 16 which is the main heat generation source is floated on the floating portion 13a of the heat sink 13 so as not to contact the back plate 11b of the case 11. Since the floating portion 13a is arranged near the top plate 11a of the case 11 and the mounting portion 13b of the heat radiating plate 13 is attached to the back plate 11b near the bottom plate 11d of the case 11, the heat generated by the backflow prevention diode 16 Is transferred from the raised portion 13a of the heat radiating plate 13 → the mounting portion 13b → the back plate 11b of the case 11 → the top plate 11a, and the heat conduction distance to reach the top plate 11a is increased, thereby suppressing the temperature rise of the top plate 11a be able to.

  As an example, on the back plate 11b of the case 11 (steel plate: plate thickness 1.2 mm × opening width 250 mm × 250 mm × depth 100 mm) of the solar cell junction box 10, the heat radiating plate 13 (plate thickness 3 mm × vertical width 135 mm × width) 250mm) mounting portion 13b (vertical width 80mm x lateral width 250mm) is attached so that the temperature rise (ΔT) when four backflow prevention diodes 16 (total heating value 30W) are attached to the floating portion 13a. It was measured.

  1-5 is a back perspective view showing a temperature rise during power generation of the solar cell junction box of the first embodiment, and FIG. 1-6 is a conventional solar cell junction box (of the heat sink 13) shown as a comparative example. It is a back surface perspective view which shows the temperature rise of the whole surface contacts the backplate 11b. In FIG. 1-5 and FIG. 1-6, the area | region where the heat sink 13 contacts the backplate 11b of the case 11 is shown with the broken line.

  In the conventional solar cell junction box shown in FIGS. 1-6, since the contact area between the heat sink 13 and the back plate 11b of the case 11 is close to the top plate 11a, the heat generated by the backflow prevention diode 16 as the main heat source is The temperature of the plate 11a is increased by 30K to 40K. On the other hand, as shown in FIG. 1-5, the solar cell junction box 10 of Embodiment 1 has a contact area between the radiator plate 13 and the back plate 11b of the case 11 that is far from the top plate 11a. The temperature rise is 10K, and the effect of suppressing the temperature rise of the top plate 11a is recognized.

Embodiment 2. FIG.
FIG. 2-1 is an exploded perspective view showing Embodiment 2 of the solar cell connection box according to the present invention, and FIG. 2-2 is a front view of the solar cell connection box according to Embodiment 2 with the cover removed. FIG. 2-3 is a cross-sectional view of the solar cell connection box of the second embodiment with the cover removed.

  As shown in FIGS. 2-1 to 2-3, the solar cell connection box 20 of the second embodiment is attached at the attachment portion 23 b attached to the back plate 11 b of the case 11 with the screw 14 and the bent portion at the intermediate portion. And a heat sink 23 having a raised portion 23a that is raised stepwise from the portion 23b. The raised portion 23 a of the heat radiating plate 23 is parallel to the back plate 11 b of the case 11. The floating portion 23a of the heat radiating plate 23 is disposed near the top plate 11a of the case 11, and the mounting portion 23b is disposed near the bottom plate 11d.

  Four (a plurality of) switches 15 are mounted side by side in the mounting portion 23 b of the heat sink 23, and a terminal block 17 is mounted next to the switch 15. In addition, four (a plurality) of backflow prevention diodes 16 that generate heat are arranged side by side in the horizontal direction on the floating portion 23 a of the heat sink 23.

  The solar cell junction box 20 of the second embodiment is not different from the solar cell junction box 10 of the first embodiment except for the shape of the heat sink 23 described above. The solar cell connection box 20 of Embodiment 2 has the same temperature rise characteristic of the top plate 11a as the solar cell connection box 10 of Embodiment 1 shown in FIGS. 1-5.

  Since the solar cell junction box 20 of the second embodiment has the mounting surface (lifting portion 23a) of the backflow prevention diode 16 of the heat sink 23 parallel to the release surface of the case 11, the solar cell of the first embodiment Compared with the connection box 10, the backflow prevention diode 16 is attached and the workability of wiring is better.

Embodiment 3 FIG.
FIG. 3-1 is an exploded perspective view showing Embodiment 3 of the solar cell connection box according to the present invention, and FIG. 3-2 is a front view of the solar cell connection box according to Embodiment 3 with the cover removed. FIG. 3C is a cross-sectional view of the positive battery connection box of the third embodiment with a cover removed.

  As shown in FIG. 3A to FIG. 3C, the solar cell connection box 30 of the third embodiment is attached with an attachment portion 33b attached to the back plate 11b of the case 11 with screws 14 and a bend line at the middle portion. A heat radiating plate 33 having a floating portion 33a bent at a right angle with the portion 33b is provided. The raised portion 33 a of the heat radiating plate 33 is perpendicular to the back plate 11 b of the case 11. The floating portion 33a of the heat radiating plate 33 is disposed near the top plate 11a of the case 11, and the mounting portion 33b is disposed near the bottom plate 11d.

  Four (a plurality of) switches 15 are mounted side by side in the horizontal direction on the mounting portion 33 b of the heat radiating plate 33, and the terminal block 17 is mounted next to the switch 15. In addition, four (a plurality) of backflow prevention diodes 16 that generate heat are arranged side by side in the horizontal direction on the floating portion 33 a of the heat radiating plate 33.

  The solar cell junction box 30 of the third embodiment is not different from the solar cell junction box 10 of the first embodiment except for the shape of the heat radiating plate 33 described above. In the solar cell junction box 30 of the third embodiment, the mounting surface (lifting portion 33a) of the backflow prevention diode 16 of the heat radiating plate 33 is perpendicular to the back plate 11b of the case 11, so The heat conduction distance to the top plate 11a of 11 becomes further longer, and the temperature rise of the top plate 11a can be further suppressed. In actual measurement, it was confirmed that the temperature rise of the top plate 11a was 5K lower than the value shown in FIG. 1-5.

  In the solar cell connection box 30 of the third embodiment, the backflow prevention diode 16 is attached to the upper side of the floating portion 33a, but may be attached to the lower side of the floating portion 33a.

DESCRIPTION OF SYMBOLS 10 Solar cell connection box 11 Case 11a Top plate 11b Back plate 11c Wiring hole 11d Bottom plate 12 Cover 13, 23, 33 Heat sink 13a, 23a, 33a Lift part 13b, 23b, 33b Attachment part 14 Screw 15 Switch 16 Backflow prevention Diode 17 Terminal block 18 Wiring 50 Solar battery 60 Power conditioner 90 Solar power generation system

Claims (4)

A rectangular parallelepiped case with the front open,
A heat radiating plate having a mounting portion attached near the bottom plate of the back plate of the case and a floating portion arranged near the top plate of the case and rising from the back plate;
A switch attached to a mounting portion of the heat sink and connected to a solar cell outside the case;
A backflow prevention diode attached to the floating portion of the heat sink and connected between the switch and an external power conditioner;
A solar cell junction box comprising:   The solar cell junction box according to claim 1, wherein the floating portion of the heat sink is inclined with respect to the back plate of the case.   The solar cell junction box according to claim 1, wherein the floating portion of the heat radiating plate is parallel to the back plate of the case.   The solar cell junction box according to claim 1, wherein the floating portion of the heat radiating plate is perpendicular to the back plate of the case.

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