JP2007189256A - Terminal box for solar cell modules - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive, simple structure terminal box meeting the condition that a temperature rise in diode 13 does not exceed a junction temperature. <P>SOLUTION: A plurality of reverse current prevention diodes 13 are arranged in parallel between adjacent terminal assemblies 12 each of which is connected to an electrode a of a solar battery module M, and the current i of each diode is decreased to a level determined by dividing the current by the number of diodes connected in parallel, resulting in heating value decrement. A temperature switch 19 is connected in series to each diode 13, and the switch 19 is turned on or off to prevent a temperature rise in each diode 13. In this way, the reliability of heat resistance in the backflow prevention diodes can be maintained without using expensive heat resistance diodes as long as the load of output current is shared among a number of diodes, and a temperature rise in each diode 13 is prevented by means of the temperature switch 19. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a terminal box used when connecting solar cell modules constituting a photovoltaic power generation system that directly converts sunlight energy into electric energy.

  As shown in FIG. 14, the solar cell system includes a solar cell panel (solar cell module) M arranged on the roof of a house, and various electric devices from the module M through a junction box Q, an inverter R, and a distribution board S. E is powered. The solar cell modules M are all arranged so as to be flush with each other, and are connected in series or in parallel via the terminal box B. The terminal box B is adhered and fixed to the back surface of the module M while maintaining the watertightness of the sealing material.

Conventionally, as shown in FIG. 15, the terminal box B has a pair of terminal plates 2, 2 to which a positive electrode a and a negative electrode a of a solar cell module M are connected in parallel in a box body 1 having an upper surface opening. The backflow prevention (bypass) diode 3 is provided between the terminal plates 2 and 2, and an external connection cable P is connected to each of the terminal plates 2 and 2 (Patent Document 1). reference). In the figure, 6 is a cover.
Japanese Patent Laid-Open No. 11-26035

In this terminal box B, today, there is also an aspect in which a plurality of terminal plates 2 are provided to connect a plurality of solar cell modules M from the viewpoint of improving the performance of the solar cell module M and collecting current efficiency (patent) Reference 2). This terminal box B is also provided with a backflow preventing diode 3 between adjacent terminal plates 2.
JP 2002-359389 A

  With today's widespread use of photovoltaic systems, durability and reliability become a problem, and the terminal box B is no exception. As a requirement of the durability and reliability of the terminal box B, for example, at an ambient temperature of 75 degrees, even if a load of 1.25 times the output current is applied for 1 hour, the temperature rise value of the diode 3 is the junction temperature ( There are conditions that do not exceed the guaranteed operating temperature.

  In order to satisfy this condition, a diode 3 having a high junction temperature may be used, but such a diode is expensive.

  An object of the present invention is to satisfy the condition that the temperature rise value of the diode 3 does not exceed the junction temperature with a simple structure and low cost.

In order to achieve the above object, the present invention pays attention to the fact that if a load of output current is borne by a plurality of diodes, the current value borne by one diode is reduced, and a diode is placed between adjacent terminal plates. A plurality of them are provided in parallel.
If the output current I of the solar cell module M flows through a circuit of a plurality of parallel diodes, the current i flowing through each of the diodes is one-third of the number in parallel, for example, one-third if there are three parallels. (I = 3i). If the flowing current value decreases, the amount of heat generated also decreases.

Here, when diodes are provided in parallel, an equal current flows through each diode if the conduction resistances of the diodes are the same. However, it is very difficult to manufacture diodes of the same standard with uniform resistance, and if manufactured, they are expensive.
On the other hand, generally, when diodes are arranged in parallel, a current with a tilted current is generated in a diode having a small resistance value.
Therefore, as long as this drift does not become a problem, a configuration in which the diodes of the present invention are arranged in parallel can be adopted, and the cost of the solar cell module terminal box can be reduced.
However, when it is desired to prevent the drift, the present invention adopts the resistance for preventing the drift.

In addition, the amount of heat generated by the diode varies depending on the difference in resistance value, and the drift increases if the temperature difference occurs in the diode due to the heat generation, for example, because the resistance value difference also increases.
For this reason, the present invention releases the heat generated by the diode. In addition, the temperature between the parallel diodes is made uniform.

As described above, according to the present invention, since the load of the output current is borne by the plurality of diodes, the reliability of the diode can be maintained without using an expensive heat-resistant diode. This is inexpensive and has a simple structure.
Further, the drift can be prevented by providing a resistance for preventing the drift or the like, releasing the heat generated by the diode (dissipating heat), or equalizing the temperature between the parallel diodes.

  As one embodiment of the present invention, a solar cell module in which a plurality of terminal plates to which electrodes of a solar cell module are connected is disposed in a box body, and a backflow prevention diode is provided between the adjacent terminal plates. In the terminal box for use, a configuration in which a plurality of the diodes are provided in parallel between the adjacent terminal plates can be employed.

At this time, it is preferable that each diode is connected in series with a current prevention resistor so that the load of each diode is uniform. Each of the resistors is appropriately set based on a value obtained by an experiment or the like based on the temperature rise based on the mounting mode of each diode.
In addition, a temperature switch is connected in series with each diode, and before each diode reaches its own junction temperature, the switch cuts off the current. When the temperature of the diode drops, the switch turns on and the current flows to the diode. To prevent the diode from rising in temperature.

Furthermore, it is possible to provide a heat transformer plate that is in continuous contact with each diode, and the heat transformer plate can radiate heat from each diode and make the temperature uniform. Diffusion is prevented by the heat dissipation and temperature uniformity of each diode.
This heat transformer plate can be provided in each of the above embodiments, and at that time, it can be provided continuously and integrally with the terminal plate.

As another embodiment of the present invention, a solar cell in which a plurality of terminal plates to which an electrode of a solar cell module is connected is disposed in a box body, and a backflow prevention diode is provided between the adjacent terminal plates. In the module terminal box, it is possible to adopt a configuration in which a heat radiation piece is provided on each terminal plate.
Diffusion is prevented by heat radiation by the heat radiation piece. The mode of the heat dissipating piece is appropriately set so that the effect can be sufficiently obtained by experiments or the like. This heat radiation piece can also be provided continuously and integrally with the terminal plate.

  The parallel connection of the diodes or the embodiment of the heat transformer plate and the heat dissipating piece can be used in combination, and at that time, the heat transformer plate can be shared by all or a part of the heat dissipating piece (terminal plate). In addition to the combined embodiments, in individual embodiments, the heat dissipation plate, the heat dissipation fins, and the heat dissipation holes can be formed in the box body to suppress the temperature rise of the diode.

Further, in each of the above embodiments, a plurality of backflow prevention diodes provided in parallel between the adjacent terminal plates can be arranged in a staggered pattern in the parallel direction of the terminal plates.
In this way, the backflow prevention diodes that serve as the heat sources are alternately shifted left and right in the parallel direction between the terminal plates, and the heat sources are scattered. Efficiency increases and the temperature rise of the diode can be further suppressed.
At this time, it is preferable that the diode is brought close to the end between the terminal plates to widen the dispersion range.

  In each of the above configurations, it is preferable that the backflow prevention diode is connected to the terminal plate by fitting the leg of the backflow prevention diode into the fitting hole of the terminal plate. Due to soldering, the diode is damaged to some extent and the resistance value fluctuates, but this mating connection eliminates the need for conventional soldering connections and eliminates fluctuations in resistance values due to soldering. Can do.

  FIG. 1A to FIG. 1F show an embodiment, in which a solar cell is placed in a rectangular box body 11 made of a polyphenylene oxide (PPO) resin or a polyphenylene ether (PPE) resin having an opening on the top surface. Two pairs of terminal plates 12 (four terminal plates 12) to which the plus electrode a and the minus electrode a of the module M are connected are arranged in parallel. The electrodes a and a are soldered to the middle of the terminal board 12 through the through holes 11a. Preliminary solder 14 is provided in advance at the connection point of the terminal plate 12 of the electrode a.

  Between the adjacent terminal plates 12, backflow prevention (bypass) diodes 13 are respectively provided on the upper and lower sides, and a heat radiating sheet 15 made of a highly thermally conductive resin is covered on the entire front surface of the terminal plate 12 and the like. The heat radiation sheet 15 is formed with a connection hole 15a for the electrode a.

  Two external connection cables P are connected to both ends of the lower side of the box body 11 (lower side in FIG. 1a). The cables P are respectively crimped or welded to the terminal plates 12 at both ends where the conductors are arranged in parallel. Connected and fixed to the box body 11 by a cable lock 17 including a retaining ring 17a and the like. At the other end of the cable P, a male connector 21 or a female connector 22 is provided, and these female or male connectors 21 and 22 are connected to the male or female connectors 22 and 21 of the adjacent terminal box B.

  A cover 16 made of PPO resin or PPE resin is fitted to the upper surface opening of the box body 11 through a waterproof ring (not shown) to make it waterproof. The box body 11 is appropriately filled with silicon resin or the like. The back surface of the box body 11 is textured, and the terminal box B is fixed to the back surface of the solar cell module M with the adhesive tape 23 on the back surface.

  The terminal box B of this embodiment is attached to the back surface of the module M by adhesion and fixing while maintaining the watertightness of the sealing material, and the cable P of each terminal box B is connected to the female or male connector 22, 21 of the adjacent terminal box B. Connect as appropriate. Each terminal box B is connected in series or in parallel by appropriately selecting the connection mode.

  In this embodiment, if the output current I of the solar cell module M flows through the circuit of the two pairs of parallel diodes 13 and 13, the current i flowing through each of the diodes 13 and 13 is halved (I = 2i) The diode 13 whose calorific value due to the current value does not exceed the junction temperature may be used.

  FIG. 2 and FIG. 3 show other embodiments. In the embodiment shown in FIG. 2, a current prevention resistor 18 is connected in series to each diode 13 so that the load of each diode 13 is made uniform. is there. The equalization is performed after each diode 13 is installed, so that a uniform current flows through the diode 13 by an actual continuity test (so that the resistance value of each series circuit of the diode 13 and the resistor 18 is the same). Set the value appropriately.

  In the embodiment shown in FIG. 3, a temperature switch 19 such as a thermostat switch is connected in series to each diode 13, and before each diode 19 reaches its own junction temperature, the current is cut off by turning off the switch 19. When the temperature of the diode 13 is lowered, the switch 19 is turned on so that a current flows through the diode 13 to prevent the temperature of the diode 13 from rising.

In the embodiment shown in FIG. 4, the heat dissipating piece 20 is continuously and integrally provided on the terminal board 12, and the terminal board 12 is formed on both side edges of the conventional terminal board as shown in FIG. The heat radiation piece 20 is protruded to increase the surface area. As shown in FIG. 4D, the terminal plate 12 is fitted to the box body 11 with the heat dissipating piece 20 standing and bent, and the heat dissipating effect is improved by increasing the surface area of the heat dissipating piece 20.
In this embodiment, the cable lock 17 is fitted to the cylinder 17b integrated with the box body 11 with the eccentric stopper 17c shown in FIG. The cable P is fixed and prevented from coming off by the pressure contact degree based on the degree of rotation based on these numbers, and the state is fixed to the screw 17d.

In each of the above-described embodiments, the number of terminal plates 12 arranged in parallel depends on the number of solar cell modules M connected to one terminal box B. It is arbitrary such as 6 sheets, 2 sheets, 3 sheets, 5 sheets, 6 sheets,... Shown in FIG. Further, the number of diodes 13 in parallel is not limited to two, but may be three, four, five, etc. shown in FIG.
When the terminal board 12 is an even number, the pair of terminal boards 12 and 12 are made to correspond to one module M. When the terminal board 12 is an odd number, for example, the connection mode shown in FIG.
As the aspect of the terminal plate 12 with the heat radiation piece 20, as long as the heat radiation effect can be obtained, it is arbitrary. For example, the heat radiation piece 20 shown in FIGS. 6 (a) to 6 (c) and FIG. For example, a wavy shape can be adopted. In this aspect, the terminal plate 12 stands and the heat dissipation effect is improved. That is, the terminal board 12 has the function of the heat dissipation piece 20.

Furthermore, if the heat transformer plate 30 continuously contacting each diode 13 is provided and the heat transformer plate 30 radiates heat from each diode 13 and makes the temperature uniform, the temperature of each diode 13 becomes uniform. Thus, drift can be prevented.
The heat transformer plate 30 may be any material as long as it has high thermal conductivity. For example, the heat transformer plate 30 is made of brass according to the number of parallel diodes 13 shown in FIGS. 9A and 9B. An embodiment having the fitting groove 31 of the lead leg 13a is conceivable. As for the attachment, the attachment form shown by the chain lines in FIG. 1 (d) is the same as that shown in FIG. 1 (a), and the one shown in FIG. 4 (a) and FIG.

  Further, as shown by a chain line in FIG. 10, when the diode 13 is brought into contact with the terminal plate 12 with the main body standing, the portion of the terminal plate 12 in contact with the diode 13 becomes the heat transformer plate 30 (terminal plate 12 Part of the heat transformer plate 30). At this time, since the terminal plate 12 also serves as the heat radiating plate 20, only the contacted portion may be used (the whole of the terminal plate 12 may also serve as the heat transformer plate 30).

  Furthermore, as shown in FIG. 11, if a plurality of backflow prevention diodes 13, 13 provided in parallel between the terminal plates 12 are arranged in a staggered pattern in the parallel direction of the terminal plates 12, a heat source is generated. Since the diodes 13 are alternately shifted to the left and right in the parallel direction between the terminal plates 12 and the heat sources are scattered, the heat dissipation efficiency through the terminal plates 12 and the like is increased, and the temperature of the diodes 13 is increased. It can be further suppressed. At this time, it is preferable that the diode 13 is moved toward the end between the terminal plates 12 to widen the scattering range.

Other modes of the terminal plate 12 are shown in FIGS. 13A and 13B. The terminal plate 12 also exhibits a heat transformer function depending on the heat radiation function and the mounting mode, and as a mode of loading into the terminal box B, as shown in FIG. For example, the terminal board 12 can be appropriately provided in the box body 11 shown in FIG.
In the embodiment shown in FIG. 12, the terminal board 12 shown in FIG. 13A is attached by locking the locking piece 32 to the locking piece 11 d of the box body 11. The terminal board 12 shown in FIG. 13B is attached by fitting its locking hole (locking piece) 21 to the claw 11 c of the box body 11. In this embodiment, each terminal plate 12 exhibits the heat dissipation function of the heat dissipation piece 20, and exhibits the function of equalizing the temperature of the heat transformer plate 30 when the main body of the diode 13 is in contact therewith.

  Incidentally, in the case where the diode 13 is not provided between the terminal plates 12, when conducting between the terminal plates 12, as shown in FIG. 12, the conductor 33 is inserted into the fitting groove 31 between the both terminal plates 12. Do by fitting. The number of the conductors 33 is arbitrary.

In each embodiment, the temperature increase of the diode 13 can be suppressed by integrally or separately forming a heat radiating plate, a heat radiating fin, and a heat radiating hole in the box body 11.
Further, as shown in FIGS. 6 c, 9, 12, etc., the diode 13 is connected to the terminal plate 13 by fitting its lead leg 13 a into the groove 31, and the fitting of the diode 13 into the groove 31 causes the diode 13 to be connected. If the connection characteristic to the terminal board 12 is ensured, soldering is not required, the thermal stress at the time of soldering connection is eliminated, the performance degradation of the diode 13 due to the thermal stress can be prevented, and the performance degradation is based on the performance degradation. The fluctuation of the resistance value can be eliminated.

  Further, when the diode 13 is connected to the terminal plate 12 by soldering, when the heat dissipating piece 20 or the like is provided and the diode 13 can be connected to the terminal plate 12 through the heat dissipating piece 20 or the like by the long lead leg 13a. As shown in FIG. 11, it is preferable to perform soldering b at a position away from the diode body so as to minimize the thermal stress during the soldering connection. At this time, the solder connection can be used together with the fitting connection to the groove 31.

Partially omitted front view of one embodiment Side view of the same embodiment Partially omitted rear view of the embodiment Partially omitted front view with the cover of the embodiment removed XX sectional view of FIG. 1d YY sectional view of FIG. Schematic front view of another embodiment Schematic front view of another embodiment Front view partially omitted from another embodiment Rear view of the same embodiment Plan view before assembling the terminal board of the same embodiment The perspective view of the terminal board etc. of the same Example The eccentric stopper of the cable lock of the Example is shown, (a) is a plan view, (b) is a front view, (c) is a bottom view, and (d) is a perspective view. Partially omitted front view with the cover of another embodiment removed Partially omitted front view with the cover of another embodiment removed Cut side view of the same embodiment Partial perspective view of the terminal board etc. of the same embodiment The terminal board of the Example is shown, (a) is a plan view, (b) is a side view, (c) is a cut side view, (d) is a sectional view taken along line XX of (a), (e) is YY sectional view Schematic electrical connection wiring diagram of solar cell module and terminal box Perspective view of each example of heat transformer plate Plan view of another example of heat transformer plate Partially omitted front view with the cover of another embodiment removed The perspective view which removed the cover of other Examples It is a perspective view of each component of the Example, (a) is a heat transformer board, (b) is a heat sink, (c) is a box main body. Schematic diagram of solar power generation system (A) is a plan view of a conventional example, (b) is a longitudinal sectional view thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Box body 2, 12 Terminal board 3, 13 Backflow prevention diode 13a Backflow prevention diode lead leg 15 Heat radiation sheet 18 Current drift prevention resistor 19 Temperature switch 20 Heat radiation piece 30 Heat transformer board 31 Backflow prevention diode mounting Mating groove a Solar cell module electrode B Terminal box M Solar cell module P External connection cable

Claims (11)

A plurality of terminal plates (12) to which the electrode (a) of the solar cell module (M) is connected are disposed in the box body (11), and a backflow preventing diode is provided between the adjacent terminal plates (12). In the solar cell module terminal box (B) provided with (13),
A plurality of the backflow prevention diodes (13) are provided in parallel between the adjacent terminal plates (12), and a heat transformer plate (30) continuously contacting each backflow prevention diode (13) is provided. The heat transformer plate (30) is made of the same plate material as the terminal plate (12) and is formed integrally and continuously with the terminal plate (12). A terminal box for a solar cell module, characterized in that the diode (13) dissipates heat and the temperature is made uniform.   The terminal plate (12) has the heat transformer plate (30) rising from the side edge thereof, and the countercurrent flows into the groove (31) that opens to the upper edge of the heat transformer plate (30) and extends downward. 2. The solar cell according to claim 1, wherein a leg (13 a) of the prevention diode (13) is fitted from the upper edge opening of the groove (31) and is provided between the adjacent terminal plates (12). Module terminal box.   The terminal box for a solar cell module according to claim 1 or 2, wherein the heat transformer plate (30) is also used as a heat radiating piece (20).   The terminal box for a solar cell module according to claim 1 or 2, wherein a heat dissipating piece (20) is provided on the heat transformer plate (30). A plurality of terminal plates (12) to which the electrode (a) of the solar cell module (M) is connected are disposed in the box body (11), and a backflow preventing diode is provided between the adjacent terminal plates (12). In the solar cell module terminal box (B) provided with (13),
A plurality of the backflow prevention diodes (13) are provided in parallel between the adjacent terminal plates (12), and a heat transformer plate (30) separate from the terminal plate (12) is provided for each backflow prevention diode ( 13) is fitted to the legs (13a) and is in contact with the respective backflow prevention diodes (13), and the heat transformer plate (30) is used to radiate heat from each backflow prevention diode (13) and temperature. A terminal box for a solar cell module, characterized in that it is made uniform.   The terminal plate (12) is provided with a heat dissipating piece (20), and the heat dissipating piece (20) is made of the same plate material as the terminal plate (12) and protrudes from the side edge of the terminal plate (12). The solar cell module terminal box according to claim 5. A plurality of terminal plates (12) to which the electrode (a) of the solar cell module (M) is connected are disposed in the box body (11), and a backflow preventing diode is provided between the adjacent terminal plates (12). In the solar cell module terminal box (B) provided with (13),
A plurality of the backflow prevention diodes (13) are provided in parallel between the adjacent terminal plates (12), and a heat dissipating piece (20) is provided on each terminal plate (12), and the heat dissipating piece (20) A terminal box for a solar cell module, comprising the same plate material as the terminal plate (12) and protruding from a side edge of the terminal plate (12).   The terminal box for a solar cell module according to claim 7, wherein the heat dissipating piece (20) is bent upright from the terminal plate (12).   The terminal box for a solar cell module according to claim 8, wherein the radiating piece (20) bent upright is further bent in a wave shape to the side.   The leg (13a) of the backflow prevention diode (13) is inserted into the groove (31) which opens to the upper edge of the heat dissipating piece (20) standing up from the side edge of the terminal plate (12) and extends downward. The terminal box for a solar cell module according to claim 8 or 9, wherein the terminal box is fitted between the upper edge openings 31) and provided between the adjacent terminal plates (12). A plurality of terminal plates (12) to which the electrode (a) of the solar cell module (M) is connected are disposed in the box body (11), and a backflow preventing diode is provided between the adjacent terminal plates (12). In the solar cell module terminal box (B) provided with (13),
A plurality of the backflow prevention diodes (13) are provided in parallel between the adjacent terminal plates (12), and a temperature switch (19) is connected in series to each backflow prevention diode (13). A terminal box for a solar cell module, wherein the temperature rise of each backflow prevention diode (13) is prevented by turning on and off of (19).

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