JP2006147737A - Terminal box for photovoltaic panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal box for a photovoltaic panel, in which the temperature of a bypass diode can be confined within an appropriate working temperature by efficiently dissipating heat generated from the bypass diode incorporated in the terminal box for the photovoltaic panel. <P>SOLUTION: The terminal box for a photovoltaic panel comprises a housing, a plurality of terminal boards incorporated in the housing, and a bypass diode for interconnecting the plurality of terminal boards. A heat transmission member, composed of a high heat conductive material, is arranged on the bottom plate of the housing intended to face the photovoltaic panel, and the bypass diode is applied tightly onto the heat transmission member. Consequently, heat generated during operation of the bypass diode is transmitted, at first, to the entire heat transmission member and then transmitted effectively from individual places of the heat transmission member to the photovoltaic panel via the bottom plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solar cell panel terminal box for electrically connecting a plurality of solar cell panels to each other. In particular, the present invention is a solar cell panel terminal box that can keep the temperature of the bypass diode within an appropriate operating temperature by efficiently dissipating heat generated by the bypass diode incorporated in the terminal box to the solar cell panel. About.

  A large number of solar cell panels are arranged on the roof of a sunny house to increase the amount of power generation. As shown in FIG. 1, each solar cell panel P has a terminal box B attached to its back surface, and electrically connects the terminal boxes B of adjacent solar cell panels P via external connection cables 5. use.

  Next, a conventional example of the inside of the terminal box B is shown in FIG. FIG. 2 is a schematic diagram of the inside of the conventional terminal box B with the cover plate removed. In the figure, 1 is a bottom plate, 2 is a bottom plate opening, 3 is a side wall, 4 is a terminal plate, 5 is an external connection cable, and 6 is a bypass diode.

  The bottom plate 1 is a portion of the casing that faces the solar cell panel when the terminal box is attached to the solar cell panel. The bottom plate 1 also has a bottom plate opening 2, and when the bottom plate 1 is attached to the solar cell panel, the positive electrode and the negative electrode coming out of the solar cell panel are passed from the bottom plate opening 2 to the inside of the housing. .

  A side wall 3 is erected on the outer periphery of the bottom plate 1 so as to surround the outer periphery of the bottom plate 1. A lid plate (not shown) is provided on the side wall at a distance from the bottom plate 1 so as to face the bottom plate 1. These bottom plate, side wall, and lid plate are resin molded products having low thermal conductivity.

  A pair of terminal plates 4 are attached on the bottom plate 1 inside the housing. One end of each of these terminal plates is connected to the external connection cable 5, and the other end is connected to a plus electrode or a minus electrode (not shown) protruding from the solar cell panel. Further, a bypass diode 6 is incorporated inside the housing, and the pair of terminal plates are connected to each other.

  This bypass diode is for short-circuiting the current due to application of the reverse voltage from one external connection cable to the other external connection cable when the electromotive force of the solar cell panel is lowered. In a solar cell panel, the electromotive force of the panel may decrease due to various reasons. For example, some of the cells that make up the solar panel are damaged by the impact of heavy objects such as stones, or sunlight is incident on some of the cells that make up the solar panel due to the effects of building shadows or snowfall. When is blocked, the electromotive force in the solar cell panel is lowered. In this case, a voltage generated in another solar cell panel that normally generates power is applied in the form of a reverse voltage to the solar cell panel whose electromotive force is reduced. This not only reduces the power generation amount of the entire solar cell panel, but also causes an abnormal heat generation phenomenon (hot spot) in the solar cell panel whose electromotive force is reduced. The bypass diode is provided to prevent such a decrease in the amount of power generation and the occurrence of abnormal heat generation, and short-circuit the current when one reverse voltage is applied from one connection cable to the other. It plays a role of bypassing the solar cell panel whose power is lowered.

  By the way, when a bypass diode plays the above-mentioned role, since a large current flows in the forward direction of the diode, the bypass diode generates heat violently and may exceed the proper operating temperature of the diode. If the diode exceeds its proper operating temperature, it will not function as a diode (thermal runaway), and the diode and peripheral circuits may be destroyed. Further, even if the diode and the peripheral circuit are not destroyed, the life of the diode is remarkably shortened if such thermal runaway is repeated. Therefore, it is necessary to efficiently dissipate the generated heat so that the heat generated during the operation of the bypass diode does not exceed the proper operating temperature of the bypass diode.

  The technology to dissipate the heat generated from the bypass diode built into the terminal box for solar panel includes heat dissipation from the surface of the terminal box to the surrounding atmosphere, and heat dissipation to the surrounding atmosphere through the terminal board and external connection cable. A technique using a temperature difference between the bypass diode surface and the surrounding atmosphere has been conventionally applied. However, such heat dissipation technology is not very efficient, and it is extremely difficult to keep the temperature of the bypass diode within the appropriate operating temperature of the diode in all environments when the actual usage environment is considered.

  On the other hand, European standards have recently changed the standard for the temperature at the time of use of the terminal box for solar cell panels, and it is required to further reduce the temperature at the time of use of the terminal box for solar cell panel to prevent fire. This trend will certainly spread to Japan in the future. Therefore, keeping the temperature of the solar cell panel terminal box low by keeping the temperature of the bypass diode within the proper working temperature of the diode is a performance that will surely be required in Japan in the future.

  By the way, in the computer field, as a technique for dissipating heat generated from a diode, forced cooling by using a cooling fan in combination and heat radiation to the atmosphere by attaching a diode to a heat sink are generally performed.

  However, if these techniques are simply applied to a bypass diode incorporated in a terminal box for a solar cell panel, various inconveniences are considered. For example, when a cooling fan is used in combination, the power for operating the fan will be lost, and the cost will be extremely high. In addition, when a heat tank is used, there is no power loss, but the volume is extremely large, so that the terminal box for a solar cell panel surrounding the heat tank will have to be enlarged. Further, when using a heat tank, it is necessary to preliminarily treat rust in consideration of the installation environment of the solar cell panel terminal box that is exposed to wind and rain, which will increase costs.

As described above, none of these heat dissipation techniques known in the field of computers is suitable for application to a bypass diode incorporated in a terminal box for a solar cell panel. Therefore, it is necessary to develop a unique heat dissipation technique suitable for the bypass diode incorporated in the terminal box for solar cell panel.
JP 2001-135847 A

  The present invention was devised in view of the current state of the prior art, and its purpose is to efficiently dissipate the heat generated by the bypass diode incorporated in the terminal box for the solar cell panel without changing the appearance of the terminal box. Accordingly, it is an object of the present invention to provide a terminal box for a solar cell panel in which the temperature of the bypass diode can be suppressed within an appropriate use temperature.

  In order to solve the above problems, the present inventor has conducted intensive research on an efficient heat dissipation mechanism from a bypass diode incorporated in the terminal box for a solar cell panel. As a result, the heat generated by the bypass diode is not the ambient atmosphere but the sun. Surprisingly, it was found that heat can be efficiently dissipated when the battery panel is escaped, and the present invention has finally been completed.

That is, the present invention relates to a terminal panel for a solar cell panel including a housing, a plurality of terminal plates incorporated in the housing, and a bypass diode connecting the plurality of terminal plates to each other.
A heat transfer member made of a highly heat conductive material is disposed on the bottom plate of the housing intended to face the solar cell panel, and the bypass diode is in close contact with the heat transfer member, whereby the bypass The heat generated during the operation of the diode is first transferred to the entire heat transfer member, and then effectively transferred from the individual locations of the heat transfer member to the solar panel through the bottom plate. It is a terminal box for solar cell panels.

  In one preferred embodiment of the present invention, a heat radiating plate made of a high thermal conductivity material is disposed in close contact with the side of the bypass diode opposite to the side where the heat transfer member is disposed, and the bypass diode is It is sandwiched between a heat transfer member and the heat radiating plate.

  In another preferred embodiment of the present invention, an end face of the heat transfer member or the heat radiating plate is raised.

  According to the terminal box for a solar cell panel of the present invention, the heat generated by the bypass diode incorporated in the terminal box can be efficiently radiated toward the solar cell panel, so that the temperature of the bypass diode is appropriately used. Can be kept within temperature. Moreover, as a result, the temperature at the time of use of the terminal box for solar cell panels can be suppressed low. Moreover, according to the terminal box for solar cell panel of the present invention, these effects can be achieved without consuming extra power or increasing the size of the terminal box. Furthermore, since the solar cell panel terminal box of the present invention has a configuration in which a heat transfer member is added on the bottom plate of the conventional terminal box housing, the appearance of the terminal box is not different from the conventional one. , It does not give the customer a sense of incongruity.

  The terminal box for a solar cell panel of the present invention has a structure in which heat generated during the operation of the bypass diode is transmitted to the solar cell panel through a bottom plate of the housing intended to face the solar cell panel. It is characterized by having. Various structures are conceivable as such a structure, and examples thereof include a structure as shown in FIG.

  FIG. 3 is a conceptual schematic diagram showing a bottom plate, a heat transfer member, and a bypass diode in one embodiment of the terminal box for solar cell panel of the present invention. In FIG. 3, other parts constituting the solar cell panel terminal box of the present invention are not drawn for easy explanation, and the dimensions and shape of the bottom plate and the heat transfer member and the arrangement of the bypass diodes are also actual. Is slightly different. In FIG. 3, reference numeral 1 denotes a bottom plate of a housing, on which a heat transfer member 7 made of a high heat conductive material such as aluminum, copper, and stainless steel is disposed. On the heat transfer member 7, a bypass diode 6 is provided. It is in close contact. In the present invention, the size of the heat transfer member is desirably at least larger than the size of the bottom surface of the bypass diode, in order to achieve the effects of the present invention, and is preferably substantially the same size as the bottom plate.

  In a conventional terminal panel for a solar cell panel, the bypass diode is arranged directly on the bottom plate made of a resin having low thermal conductivity, so that heat generated during the operation of the bypass diode is directed to the solar cell panel through the bottom plate. It was hardly transmitted, and was transmitted to the surrounding atmosphere exclusively through the surface of the terminal box, terminal board, and external connection cable. On the other hand, in the solar cell panel terminal box of the present invention, a heat transfer member made of a high heat conductive material such as aluminum, copper, and stainless steel is disposed on the bottom plate, and the bypass diode is in close contact therewith, The heat generated during the operation of the bypass diode is first transferred to the entire heat transfer member, and then efficiently transmitted over a wide area from the individual locations of the heat transfer member to the solar panel through the bottom plate. The temperature can be kept within an appropriate operating temperature.

  In other words, in the conventional terminal panel for a solar cell panel, the heat generated during the operation of the bypass diode is transmitted to the solar cell panel only through the bottom plate having a very small area directly under the bypass diode. In addition, since the thermal conductivity of the bottom plate is low, it is extremely inefficient and almost negligible. On the other hand, in the solar cell panel terminal box of the present invention, a heat transfer member made of a highly heat conductive material is provided between the bypass diode and the bottom plate, so that heat generated during the operation of the bypass diode is directly below the bypass diode. Rather than being localized in a very narrow area corresponding to the heat transfer member, it is quickly transmitted to the entire surface of the heat transfer member, and then transmitted from the entire surface of the heat transfer member to the solar cell panel via the bottom plate. Therefore, in the terminal box for solar cell panel of the present invention, not only the portion directly below the bypass diode on the bottom plate but also the entire portion contacting the heat transfer member can contribute to heat transfer from the bypass diode toward the solar cell panel. Even if the thermal conductivity of the bottom plate itself is low, heat can be transferred to the solar cell panel with sufficiently high efficiency as a whole.

  In general, heat radiation from the heat generating object is performed more efficiently as the temperature difference between the surface of the heat generating object and the heat radiation destination increases. In the case of a bypass diode incorporated in a terminal box for a solar cell panel, the surface temperature during operation of the bypass diode, which is a heating object, is 140 ° C. or higher. On the other hand, the atmospheric temperature around the bypass diode is around 40 ° C. under a normal use environment, and the surface temperature of the solar cell panel is around 80 ° C. Therefore, it has been conventionally considered that it is more efficient to select the atmosphere around the bypass diode having a large temperature difference from the bypass diode surface as a heat radiation destination. On the other hand, the present inventor unexpectedly found that when a solar cell panel is selected as a heat dissipation destination, heat dissipation is efficiently performed as a result, although the temperature difference from the bypass diode surface is smaller. This is considered to be because the speed at which heat is transferred from the bypass diode to the solar cell panel via the heat transfer member and the bottom plate is higher than the speed at which heat is transferred from the bypass diode to the surrounding atmosphere. Moreover, since the surface area of a solar cell panel is very large, it is considered that the heat transferred from the bypass diode to the solar cell panel is efficiently transferred from there to the atmosphere.

  Next, some applied embodiments of the terminal box for solar cell panel of the present invention will be described with reference to FIGS. 4 to 6 are conceptual schematic views similar to FIG. 3, and other parts constituting the terminal box for a solar cell panel of the present invention are not drawn for ease of explanation, and the bottom plate and the heat transfer member are illustrated. The size and shape of the and the arrangement of the bypass diodes are also slightly different from the actual ones.

  In the embodiment shown in FIG. 4, in the embodiment shown in FIG. 3, the heat radiating plate 8 is arranged in close contact with the side opposite to the side where the heat transfer member 7 of the bypass diode 6 is arranged. It is sandwiched between the member 7 and the heat sink 8. The heat radiating plate 8 is a thin plate made of a highly heat conductive material such as aluminum, copper, or stainless steel, and can be made of the same material as the heat transfer member 7. By disposing the heat radiating plate 8, a part of the heat generated during the operation of the bypass diode 6 is transmitted over a wide range to the ambient air on the cover plate side of the terminal box through the heat radiating plate 8. Heat dissipation can be performed.

  In the solar cell panel terminal box of the present invention, it is not necessary to directly attach the bypass diode to the heat transfer member and / or the heat sink. If the bypass diode is of a non-insulating type, an insulating material is used for safety. Can be brought into close contact with the heat transfer member and / or the heat sink. However, in this case, the insulating material needs to be such that it does not hinder heat transfer as much as possible.

  The embodiment shown in FIGS. 5 and 6 is the embodiment shown in FIG. 4 in which the end face of the heat transfer member 7 is raised (FIG. 5) or the end face of the heat sink 8 is raised (FIG. 6). is there. By raising the end face of the heat transfer member 7 or the heat radiating plate 8 in this way, a part of the heat generated during the operation of the bypass diode 6 is transmitted over a wide range to the ambient air on the side wall side of the terminal box, so that it is more efficient. Heat can be released.

  In the terminal box for solar cell panels of this invention, it is preferable from a viewpoint of rust prevention that the heat-transfer member and / or the heat sink have been subjected to weathering treatment such as alumite treatment. In this way, by subjecting the heat transfer member and / or the heat radiating plate to weathering treatment, it is possible to omit a part of the cover plate and the side wall of the housing, thereby further radiating heat from the heat transfer member and the heat radiating plate to the surrounding atmosphere. It can be done efficiently.

  In the terminal box for solar cell panel of the present invention, the high heat conductive material forming the heat transfer member and / or the heat sink can be, for example, aluminum, copper or stainless steel. Moreover, it is preferable that the surface of the heat transfer member and / or the heat radiating plate is colored in black, so that improvement in heat dissipation efficiency due to heat radiation from the heat transfer member and / or the heat radiating plate can be expected.

  When attaching the solar cell panel terminal box of the present invention to the solar cell panel, if there is an irregular uneven shape on the back surface of the solar cell panel, a sponge having good thermal conductivity between the bottom plate and the back surface of the solar cell panel -Heat transfer from the bottom plate to the solar cell panel can be stabilized by applying a flexible sheet made of a polymer material such as gel and double-sided tape.

  As described above, according to the present invention, the heat generated by the bypass diode incorporated in the terminal box can be efficiently dissipated without consuming excess power or increasing the size of the terminal box, and the temperature of the bypass diode can be set appropriately. It can be kept within the operating temperature. Moreover, since the solar cell panel terminal box of the present invention has a structure in which a heat transfer member is added on the bottom plate of the casing of the conventional terminal box, the appearance of the terminal box is not different from the conventional one. , It does not give the customer a sense of incongruity.

It is a schematic diagram which shows the back surface of a solar cell panel. It is the inside schematic diagram which removed the cover plate of the conventional terminal box. It is a notional schematic diagram of one embodiment of the terminal box for solar cell panels of the present invention. It is a conceptual schematic diagram of the application embodiment of the terminal box for solar cell panels of this invention. It is a conceptual schematic diagram of the application embodiment of the terminal box for solar cell panels of this invention. It is a conceptual schematic diagram of the application embodiment of the terminal box for solar cell panels of this invention.

Explanation of symbols

P Solar panel B Terminal box 1 Bottom plate 2 Bottom plate opening 3 Side wall 4 Terminal plate 5 External connection cable 6 Bypass diode 7 Heat transfer member 8 Heat dissipation plate

Claims (3)

In a terminal box for a solar cell panel including a housing, a plurality of terminal plates incorporated in the housing, and a bypass diode that connects the plurality of terminal plates to each other,
A heat transfer member made of a highly heat conductive material is disposed on the bottom plate of the housing intended to face the solar cell panel, and the bypass diode is in close contact with the heat transfer member, whereby the bypass The heat generated during the operation of the diode is first transferred to the entire heat transfer member, and then effectively transferred from the individual locations of the heat transfer member to the solar panel through the bottom plate. Terminal box for solar panel.   A heat radiating plate made of a highly heat conductive material is disposed in close contact with the side of the bypass diode opposite to the side on which the heat transfer member is disposed, and the bypass diode is sandwiched between the heat transfer member and the heat radiating plate. The terminal box for a solar cell panel according to claim 1, wherein: The terminal box for a solar cell panel according to claim 1 or 2, wherein an end face of the heat transfer member or the heat radiating plate is raised.

Images