JP3172419U - Connection box for photovoltaic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a junction box for a photovoltaic power generation system for cost reduction and improvement of waterproof reliability. .. SOLUTION: A plurality of switches 20 are interposed between a solar cell module and a power conditioner of a photovoltaic power generation system to open and close the connection between the solar cell module and the power conditioner in a case 10, and a power conditioner. It is a junction box for a solar cell system having a plurality of diodes for preventing backflow from the solar cell module to the solar cell module. The case 10 is composed of a case main body 11 and a cover 12 thereof, and both 11 and 12 are integrally molded by drawing to eliminate joints at corners, and the cover 12 is placed in a case via packing. It covers the main body 11. The lack of this seam and the interposition of packing improve waterproof reliability. [Selection diagram] Fig. 1

Description

  The present invention relates to a junction box installed in a solar power generation system.

In the photovoltaic power generation system, as shown in FIG. 12, a solar cell panel (solar cell module) M is arranged on the roof of a house, and from the module M through a connection box Q, a power conditioner R, and a distribution board S. Electric power is supplied to various electrical devices E (see Patent Document 1, paragraph 0002, FIG. 14).
As shown in FIG. 13, the connection box Q includes a switch 2 that disconnects the solar cell module M from the circuit in a case (case) 1 during maintenance and inspection of the solar cell module M, and a high-voltage solar cell. A backflow prevention diode (hereinafter simply referred to as “diode”) 3 for preventing current from flowing from the battery module M to the low voltage solar cell module M, and a surge absorber for protecting the solar cell module M from surge voltage such as lightning. 4 and a terminal block 5 are provided. In the figure, 6 is a hole for drawing / withdrawing the power line to the outside (see paragraph 0003 of FIG. 6 and FIG. 6).

  In this solar power generation system, a plurality of solar cell modules M are connected in series or in parallel, and each group of the solar cell modules M is led to the connection box Q as one circuit. In the junction box Q of FIG. 13, four circuits are led, and correspondingly, four switches 2, four diodes 3 and four surge absorbers 4 are provided, which are electrically connected. (Refer to FIG. 2 of the present application).

JP 2007-184646 A JP 2000-173376 A

In recent years, the number of solar cell modules M in the above group has increased from the viewpoint of improving the performance of the solar cell module M and the current collection efficiency, and the current flowing through each circuit has increased. The calorific value of is also increasing. If this calorific value is large and each device becomes high temperature, its function is reduced and it leads to destruction.
For this reason, conventionally, these devices 2, 3, 4, and 5 are provided on an aluminum chassis 7 that serves as a heat sink, and the chassis 7 is provided at a certain distance from the bottom surface of the case 1 (starts up), thereby providing a heat dissipation effect. To ensure.

  In recent years, miniaturization of each device has been requested, and this junction box Q is no exception. Further, there is a demand for further cost reduction of the connection box Q, and improvement of the waterproof reliability of the connection box is also desired.

  In the present invention, under the above circumstances, the first problem is to reduce the cost of the connection box Q and improve the waterproof reliability, and the second problem is to reduce the size of the connection box Q. The second problem is to reduce the cost by improving the durability.

In order to achieve the first problem described above, the present invention comprises a case of a junction box comprising a case body and its cover, both of which are integrally formed by drawing to eliminate the joints at the corners and packing. The cover was put on the case body through the interposition.
As described above, when the drawing process is performed, the productivity of the case can be improved and the cost can be reduced, and the waterproof reliability can be improved by interposing the packing without a joint.

  As a specific configuration of this device, a plurality of switches that are interposed between the solar cell module and the power conditioner of the photovoltaic power generation system and open and close the connection between the solar cell module and the power conditioner in the case And a junction box for a photovoltaic power generation system having a plurality of diodes that prevent backflow from the inverter to the solar cell module, the case is composed of a case body and its cover, and the case and the cover are both drawn by drawing. A structure in which the cover is covered with the case body through a packing can be adopted as the one that is integrally molded and has no joints at the corners.

  In order to achieve the second problem, the present invention pays attention to the fact that the space below the chassis 7 has conventionally been a space, and the diode 3 and the like are disposed in the space. Conventionally, if a device is arranged in a space that was a dead space, the space in which the device is arranged can be reduced, so that the junction box can be downsized.

As a specific configuration of this device, a plurality of switches that are interposed between the solar cell module and the power conditioner of the photovoltaic power generation system and open and close the connection between the solar cell module and the power conditioner in the housing And a connection box for a photovoltaic power generation system having a plurality of diodes for preventing backflow from the power conditioner to the solar cell module, the diode storage box is provided in the housing, and the storage box has a plurality of stages. A backflow prevention diode interposed between a pair of terminal plates is arranged at each stage, and a switch is provided on the storage box, and the backflow prevention diode is connected to the power conditioner and the terminal plate via the terminal plate. The structure electrically connected to the switch can be adopted.
In this way, since there is a terminal plate serving as a heat sink for each number of stages of each diode, the most heat-generating diode can be smoothly radiated (high heat dissipation).

In this configuration, it is preferable that the storage box is made of an insulating resin, and it is preferable that the storage box is divided by an insulating plate. If it partitions with this insulating board, the insulation between exceptional terminal boards will be achieved. This insulating plate may be omitted if the air layer can be insulated. Incidentally, this storage box can be adopted even when a switch is not provided thereon. For example, the conventional example of FIG. 13 can also be configured as a unit in which the diodes 3 are collected.
Furthermore, it has a terminal block for drawing out to the outside, and the terminal block can be made into an integral resin molded product with the storage box. In this way, the cost can be reduced compared to the case where a terminal block is provided separately. That is, the second problem can be achieved.

  Moreover, although the connection between each apparatus can be performed with an electric wire and its harness similarly to the past, the means by the electric wire is complicated and causes the cost increase. For this reason, for example, if the terminal plate is connected to the switch with a terminal piece continuous to the terminal plate, or if the terminal plate is connected to the terminal block with the terminal piece, the connection by the electric wire is possible. This is a so-called bus bar connection, which is advantageous in terms of cost. At this time, the terminal plate and the terminal piece can be punched out. Further, the bus bar connection has higher workability and connection reliability than the connection using the electric wire and the crimp terminal. Thereby, the third problem can be achieved.

Since this device is configured as described above, the cost of the junction box Q can be reduced and the waterproof reliability can be improved.
In addition, since a diode or the like has conventionally been arranged in a dead space below the switch, the junction box can be reduced in size.

1 shows an embodiment of the present invention, (a) is a perspective view of a state in which a lid is opened, (b) is a front view thereof Wiring diagram of the same embodiment Main part perspective view of the same embodiment Front view of FIG. Plan view of FIG. FIG. 3 is a perspective view with the switch removed. 6 is a partially removed perspective view seen from a different direction in FIG. The principal part perspective view of the diode unit part of the embodiment 8 is a partially removed perspective view seen from a different direction in FIG. Top view of the terminal board of the same embodiment (A) to (i) are respectively aa line, bb line, cc line, dd line, ee line, ff line, hh line, i-line in FIG. i-line, gg-line cross-sectional view Schematic diagram of solar power generation system Top view of conventional junction box

  FIG. 1 to FIG. 11 show an embodiment. This embodiment also has a metal casing (case) 10 in the case of maintenance inspection of the solar cell module M as shown in FIG. A switch 20 that disconnects the solar cell module M from the circuit, a diode unit 30 that prevents current from flowing from the high voltage solar cell module M to the low voltage solar cell module M, and a surge such as lightning. A surge absorber 40 that protects from voltage and a terminal block 50 are provided, and they are electrically connected as shown in FIG. In the figure, 60 is a knockout for forming a hole for drawing / withdrawing an electric power line to the outside.

  The case 10 is composed of a case main body 11 and a cover 12 thereof. Both the parts 11 and 12 are integrally formed by drawing to eliminate the joints at the corners, and are highly reliable in outdoor waterproofing measures. Yes. The cover 12 is pivotally attached to the case main body 11 via a hinge, and the case 10 is secured to the water tightness by covering the case main body 11 with the cover 12 interposed therebetween. The case main body 11 and the cover 12 are integrated by screwing the stopper pieces 13 of both.

  The switch 20 has the same structure as the conventional one shown in Patent Document 2, paragraph 0004, FIG. 7, and has an open / close mechanism inside, and a power supply terminal 22 that is a solar cell module side terminal by operating the open / close lever 21. And the load (power conditioner) side terminal 23 are turned on / off (open / close).

The diode unit 30 includes a resin-integrated molded product storage box 31, four pairs of terminal plates 32a and 32b loaded in the storage box 31, and a diode provided between the pair of terminal plates 32a and 32b. 33 etc. The switch 20 is attached to the upper surface of the storage box 31.
As shown in FIGS. 4 and 7, the storage box 31 is divided into four stages with an insulating partition plate 31a, and ribs 31b in the width direction (front and rear direction in FIG. 4) are appropriately provided on the partition plate 31a. Is provided. A part of the rib 31b gradually increases from the front side toward the back side (from front to rear in FIG. 4) (see the respective drawings in FIG. 11), and the terminal plates 32a and 32b are arranged between the partition plates 31a. The terminal plates 32a and 32b can be easily inserted from a wide opening when being loaded, and are pressed against the ribs 31b to be prevented from coming off by being pushed into the back.

  The pair of terminal plates 32a and 32b are made of a copper alloy punched product shown in FIG. 10, and are provided by inserting and welding the legs 33a between the terminal plates 32a and 32b. In this embodiment, the three diodes 33 are arranged in parallel on the pair of terminal plates 32a and 32b, but the number of the diodes 33 is arbitrary such as one, two, four or more. Thus, by arranging the diodes 33 in parallel, each of the diodes 33 shares the output current I from the solar cell module M (for example, when there are three diodes 33 as shown in the figure, each of the diodes 33). 1/3 × I current), the amount of heat generated by the diode 33 is also reduced. The slit 32c next to the leg 33a is for enhancing heat dissipation. The diodes 33 in each stage are alternately shifted in a staggered pattern in the stage direction so that the bulges do not interfere with each other.

  A terminal piece 34a protrudes from the rear edge of one terminal plate 32a, and a terminal piece 34b protrudes from the front edge of the other terminal plate 32b and is provided along the side edge. In FIG. 10, as for the terminal piece 34a of the former one terminal plate 32a, the first stage (the lowest stage) is the right end thereof, the second stage is adjacent to the left side thereof (see the one-dot chain line in FIG. 10), and the third stage. The positions of the eyes are shifted to the left (see the two-dot chain line in FIG. 10) and the fourth stage is further to the next (see the three-dot chain line in FIG. 10).

A terminal block 50 is integrally formed on one side of the storage box 31, and terminals 52, 53, to which the respective terminal pieces (bus bars) 34 b, 55 a, 55 b are screwed to the terminal block 50 by screws 51. 54 is provided. The terminal piece 34 b of the other terminal plate 32 b of each stage is guided to the one terminal 52 and connected by the screw 51. The second terminal 53 and the third terminal 54 are respectively connected to the power conditioner R on the load side, and the second terminal 53 is an L-shaped (having protruding pieces at both ends) terminal pieces (N terminals) 55a. Accordingly, the one terminal 52 is connected by a screw 51, and a terminal piece (P terminal) 55 b connected to one terminal 23 of each switch 20 is connected to the three terminals 54 by screws 51.
The other terminal 23 of each switch 20 and the terminal piece 34a of one terminal plate 32a of each stage are connected via screws 51 with L-shaped (having protruding pieces at both ends) terminal pieces 55c.

  Each pair of terminal plates 32 a and 32 b loaded with the diode 33 is inserted and loaded between the partition plates 31 a of the storage box 31 for each stage. By this loading, the terminal strips 34a and 34b of the terminal plates 32a and 32b protrude from the side and rear edges of the storage box 31, and the terminal strips 34a and 34b are connected to one terminal 52 and each switch of the terminal block 50. 20 to one terminal 23. The one terminal 52 is connected to the second terminal 53 of the terminal block 50 with an L-shaped (having protruding pieces at both ends) terminal pieces 55 a, and the other terminals 23 of each switch 20 are connected to three terminals 50. The terminal 54 is connected with a comb-shaped terminal piece (N terminal) 55b.

The surge absorber 40 is also connected to a few terminals 53 and 54 of the terminal block 50 by means of terminal pieces (bus bars) or electric wires, and electrical connection of each device (switch 20, diode 33, etc.) in this connection box Q is made. To complete.
If necessary, an insulating cover 56 made of resin is provided on an exposed portion of the terminal piece 55b and the like. The opening surface of the storage box 31 is covered with a cover 57 having a lattice-shaped through hole 57a. The covers 56 and 57 also prevent people from touching each terminal piece and terminal board.

Since the terminal box 50 is integrated with the storage box 31 and the switch 20 is provided on the upper surface of the connection box Q having this configuration, the connection box Q is more compact and has a volume of about 2/3. In addition, since a plurality of diodes 33 between the terminal plates 32a and 32b are arranged in parallel, the amount of heat generated by the diodes 33 can be suppressed, and the generated heat can be smoothly radiated by the plate-like terminal plates 32a and 32b having a wide heat radiating surface. The For this reason, the diode 33 does not become hot.
Further, since the terminal plates 32a and 32b at each stage are also insulated by the partition plate 31a, there is no possibility of short circuit.

In the above embodiment, there are four circuits from the solar cell module M (in the case of four circuits), but this device is also used in a junction box Q of one circuit, two circuits, three circuits, five circuits or more. Of course you can. In that case, of course, according to the number of circuits, the number of the switches 20 and the number of stages of the terminal plates 32a and 32b are determined appropriately. For example, in the case of 5 circuits, 5 switches 20 and 5 stages of terminal boards are used.
Further, since the diode unit 30 is a single unit in which a plurality of diodes 33 are collected and has excellent compactness and heat dissipation, the switch 20 is provided on the storage box 31 as in the above embodiment. It is also possible to adopt a mode that does not.

E Electrical equipment M Solar cell module Q Junction box R Power conditioner 1, 10 Junction box case 11 Junction box case body 12 Junction box cover 2, 20 Switch 3, 33 Backflow prevention diode 4, 40 Surge absorber 5, 50 Terminal block 30 Diode unit 31 Storage box 32a, 32b of diode unit Terminal plate 34a, 34b Terminal piece of terminal plate (bus bar)
52, 53, 53 Terminal block terminals 55a, 55b, 55c Terminal strip (bus bar)

Claims (1)

  The solar cell module (M) and the power conditioner (R) are interposed between the solar cell module (M) and the power conditioner (R) of the photovoltaic power generation system, and the solar cell module (M) and the power conditioner (R) are connected in the case (10). In the connection box (Q) for a photovoltaic power generation system having a switch (20) that opens and closes and a backflow prevention diode (33) that prevents backflow from the power conditioner (R) to the solar cell module (M), The case (10) is composed of a case main body (11) and its cover (12), and the case main body (11) and the cover (12) are both integrally formed by drawing to eliminate the corner joints. A junction box having a cover (12) covering the case body (11) with packing interposed.

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