Abstract:
Disclosed is a terminal box for a solar cell module, which has improved heat transfer properties. Specifically, disclosed is a terminal box for a solar cell module with a plurality of terminal boards ( 60 ), a case ( 10 ) which contains the terminal boards ( 60 ) and has an outer periphery ( 12 ) that surrounds the peripheries of the terminal boards ( 60 ); a bypass diode ( 80 ) which is connected to two corresponding terminal boards ( 60 ) and serve as a bypass for a reverse load; a radiator plate ( 60 ) which supports a rectifying device body ( 81 ) that is a heat generating portion of the bypass diode. The radiator plate ( 60 ) is being formed integrally with or separately from the terminal board ( 60 ); and a bottom ( 11 ) arranged between the radiator plate ( 60 ) and the solar cell module serves as a heat transferring part that has a higher heat resistance than the outer periphery ( 12 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a terminal box for use with solar cell module. 
         [0003]    2. Description of the Related Art 
         [0004]    A solar panel constituting a solar power system comprises a plurality of solar cell modules which has respective electrodes connected in series or parallel to each other via a terminal box. 
         [0005]    For example, the terminal box includes a shallow box-shaped case made of a synthetic resin, a plurality of terminal boards laid on the bottom in the case and electrically connected to the solar cell modules, and bypass diodes (rectifying devices) for reverse load, which bridge respective corresponding pairs of terminal boards. Each diode includes a body which serves as a heat-generating portion and is supported by a metallic radiator plate. The terminal boards have respective one ends to which leads of the electrode are soldered to be connected through an opening formed in the case. The terminal boards have the other ends onto which terminals of cables drawn out of the case are crimped respectively. The case has an underside bonded to a mounting surface of each solar cell module. Accordingly, upon heat generation of the diode bodies, heat is adapted to be caused to escape from radiator plates through the bottom to the solar cell module side. 
         [0006]    Japanese Patent No. 3498945 is an example of the state-of-the-art described above. 
         [0007]    When the temperatures of the diode bodies rise during operation of the diodes, the temperature of the bottom of the case is sometimes subjected to plastic deformation over a heat resistance limit of the case. Then, the underside of the case is rendered non-flat such that an air space is interposed between the underside of the case and the mounting surface of the solar cell module under the condition where the solar cell modules are mounted, whereupon there is a possibility that the heat transfer performance of the solar cell module may be reduced. 
         [0008]    The present invention was made in view of the foregoing circumstances and an object thereof is to provide a terminal box for use with a solar cell module having a beneficial effect on the heat transfer performance. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is a terminal box for use with a solar cell module, which is mounted on a solar cell module, the terminal box comprising a plurality of terminal boards; a case accommodating the terminal boards and having an outer periphery surrounding the terminal boards; bypass rectifying devices for reverse load, connected to corresponding pairs of the terminal boards; radiator plates on which rectifying device bodies serving as heat generating portions of the rectifying devices are supported, the radiator plates being configured integrally with or independent of the respective terminal boards; and heat transfer portion disposed between the radiator plates and the solar cell module and having a higher heat resistance than the outer periphery. 
         [0010]    Since the heat transfer portion has a higher heat resistance than the outer periphery of the case, the heat transfer portion is prevented from plastic deformation due to heat of the rectifying device bodies. Accordingly, intervention of an air space can be avoided between the solar cell module and the heat transfer portion, whereupon the heat transfer performance to the solar cell module can be improved. 
         [0011]    The terminal box for use with the solar cell module may be configured as follows: 
         [0012]    The case has a bottom which is located inward of the outer periphery and supports the terminal boards, and the bottom may constitute the heat transfer portion. According to this, since the case can be mounted to the solar cell module with the terminal boards being placed on the bottom, the terminal box is advantageous in the mountability. 
         [0013]    The bottom is slidingly attached along an inner edge of the outer periphery. According to this, the bottom of the case can easily be attached to the outer periphery. 
         [0014]    The terminal boards are fixed to the bottom and at least one of the terminal boards is provided with an open locking hole. The outer periphery is provided with a deflectable locking piece. When the bottom is normally attached to the outer periphery, the locking piece is elastically fitted in the locking hole, whereby the terminal boards and the bottom are held on the outer periphery. According to this, the bottom is fixed via the terminal boards to the outer periphery, whereupon the shape of the bottom is simplified. 
         [0015]    When the bottom has normally been attached to the outer periphery, a window opening is opened between the bottom and the outer periphery, and leads corresponding to groups of solar cells of the solar cell modules are drawn through the window opening into the case. This eliminates provision of a window opening specific to the bottom, whereupon the shape of the bottom is simplified. 
         [0016]    The bottom and the terminal boards are integrated by insert molding. According to this, the terminal boards are reliably prevented from separation from the bottom. 
         [0017]    The heat transfer portion is retained in an externally non-exposed state when mounted to the solar cell module. According to this, for example, the heat transfer portion can be configured by a material with a low weatherproof, whereupon a range of options in the selection of the material for the heat transfer portion is widened. 
         [0018]    The heat transfer portion is disposed at least between the rectifying device bodies and the solar cell module. This results in efficient transfer of heat generated by the rectifying device bodies to the heat transfer portion, realizing a further better heat-transfer property. 
         [0019]    The outer periphery comprises one or more of PPO (polyphenylene oxide) and PPE (polyphenylene ether), and the heat transfer portion comprises one or more of PPS (polyphenylene sulfide), PET (polyethylene terephthalate) and PBT (polybutylene terephthalate). According to this, the outer periphery is configured by a material having beneficial effects on weatherproof and hydrolysis resistance, while the bottom is configured by a material having beneficial effects on heatproof and heat transfer. 
         [0020]    The radiator plates are formed integrally with the terminal boards respectively and the terminal boards include a terminal on which no rectifying device body is supported, said terminal having a smallest surface area. Since each terminal on which the rectifying device body is supported has a larger surface area, the radiation performance of each terminal board can be improved within a limited space in the case. 
         [0021]    According to the invention, the terminal box for use with solar cell module having an improved heat transfer performance can be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a plan view of a terminal box for use with a solar cell module, according to a first embodiment of the present invention; 
           [0023]      FIG. 2  is a sectional view taken along line A-A in  FIG. 1 ; 
           [0024]      FIG. 3  is a sectional view taken along line B-B in  FIG. 1 ; 
           [0025]      FIG. 4  is a sectional view taken along line C-C in  FIG. 1 ; 
           [0026]      FIG. 5  is a plan view of a unit in which the terminal boards and the bottom are integrated with each other; 
           [0027]      FIG. 6  is a sectional view taken along line D-D in FIG.  5 ; 
           [0028]      FIG. 7  is a bottom view of the unit in which the terminal boards and the bottom are integrated with each other; 
           [0029]      FIG. 8  is a plan view of the outer periphery; 
           [0030]      FIG. 9  is a side view of a slide support; 
           [0031]      FIG. 10  is a bottom view of the case; 
           [0032]      FIG. 11  is a plan view of the terminal box for use with the solar cell module according to a second embodiment, showing the bottom on which the terminal boards are mounted; and 
           [0033]      FIG. 12  is a plan view of the bottom. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    A first embodiment of the present invention will be described with reference to  FIGS. 1 to 10 . A terminal box for use with a solar cell module (hereinafter, “terminal box”) according to the first embodiment includes a case  10 , terminal boards  60  and bypass diodes  80 . 
         [0035]    The case  10  is made of a synthetic resin and generally formed into a plate shape and comprises a bottom  11  and an outer periphery  12  surrounding the bottom  11 , as shown in  FIGS. 1 and 10 . The bottom  11  has a bottom surface formed into a flat surface  13  and mounted to the mounting surface of the solar cell module (an underside in use) in a closely adhered state. When the case  10  has been mounted to the solar cell module, the bottom  11  is hidden so as to be in an externally non-exposed state while the outer periphery  12  is exposed to the outside. 
         [0036]    The bottom  11  and the outer periphery  12  are independent of each other and are detachably attachable to each other. Furthermore, the bottom  11  and the outer periphery  12  are made of respective materials different from each other. More specifically, the outer periphery  12  is made of any one of materials of PPO (polyphenylene oxide), PPE (polyphenylene ether) and PVC (polyvinyl chloride), whereas the bottom  11  is made of any one of materials of PPS (polyphenylene sulfide), PET (polyethylene terephthalate) and PBT (polybutylene terephthalate). More specifically, the outer periphery  12  is made of a material having a superior weatherproof and hydrolysis resistance, whereas the bottom  11  is made of a material having a higher heat resistance and heat transfer property. Furthermore, the outer periphery  12  is less expensive than the bottom  11 . 
         [0037]    The outer periphery  12  has a rectangular frame-shaped peripheral wall  14  which divides a periphery of the case  10  as shown in  FIG. 8 . The peripheral wall  14  has a rear end  36  further having right and left sides formed with paired cylindrical portions  15  protruding rearward. Cables  90  which are connected to terminal boards  60  are inserted through the cylindrical portions  15  respectively. Furthermore, the rear end  36  of the peripheral wall  14  has both widthwise ends formed with paired right and left stages  16  located in front of the cylindrical portions  15 , respectively. The stages  16  are connected to both end corners of the peripheral wall  14 . The stages  16  have centrally located through holes  17  respectively. 
         [0038]    A substantially rectangular locking pieces  18  capable of locking the terminal boards  60  is formed on the widthwise central portion of the rear end  36  of the peripheral wall  14  so as to protrude frontward (inward of the peripheral wall  14 ). The locking piece  18  is elastically deformable in a vertical direction with a point on the inner surface of the peripheral wall  14  serving as a fulcrum point and has a centrally located locking protrusion  19 . 
         [0039]    The peripheral wall  14  has an inner peripheral surface on which a plurality of cover lock supports  21  is formed at peripheral intervals. A cover (not shown) has a cover lock which is locked by the cover lock supports  21 , whereby the cover is fixed to the upper end of the peripheral wall  14  and held in the fixed state. Furthermore, paired slide supports  22  are formed on the inner peripheral surface of right and left sides of the peripheral wall  14  respectively. Each slide support  22  is formed into an elongate plate shape and extends in the front-back direction along the inner peripheral surface of the peripheral wall  14  as shown in  FIG. 9 . Each slide support  22  has a front end which is located lower than a rear portion such that each slide support  22  is stepped. The front end of each slide support  22  has an upper surface serving as a first engagement support surface  23  which engages a slide  32  (as will be described later) of the bottom  11  from below. Each slide support  22  includes a part located in the rear of the front end and has an underside serving as a second engagement support surface  24  which engages the slide  32  from above. The first and second engagement support surfaces  23  and  24  serve as horizontal surfaces that occupy substantially the same heightwise positions as each other. 
         [0040]    The bottom  11  is formed integrally with the terminal boards  60  by insert molding and has a flat plate-shaped bottom wall  25  supporting the terminal boards  60 . The terminal boards  60  are arranged on the upper surface of the bottom wall  25  widthwise in parallel to each other. When the bottom  11  and the outer periphery  12  are connected to each other, a widthwise long window opening  27  is open between a front end of the bottom wall  25  and a rear end of a front end  26  of the peripheral wall  14 . Leads (not shown) corresponding to solar cell groups of the solar cell module are adapted to be drawn through the window opening  27  into the case  10 . 
         [0041]    Each terminal board  60  is made of an electrically conductive metal and formed into the shape of a flat plate. The terminal boards  60  are constituted by paired right and left cable connecting terminals  60 A which are located at both widthwise ends thereof and connected to positive and negative cables  90 , respectively and right and left relay connecting terminals  60 B located between the cable connecting terminals  60 A. The outer periphery  12  is disposed around the terminal boards  60 . Each terminal board  60  has a front end formed with an insertion hole  61 . A terminal of the lead is inserted into the insertion hole  61  to be connected by soldering or the like. Each bypass diode  80  includes a rectifying device body  81  (as will be described later) placed on the upper surface of each terminal board  60  in the middle thereof in the front-back direction, except for the relay connecting terminal  60 B located in the left side as viewed in the drawing. 
         [0042]    Each bypass diode  80  includes the rectifying device body  81  of the type that a chip thereof is covered with resin into the shape of a square block and anode side and cathode side connecting legs  82  both connected to the chip and widthwise extending from one side of the rectifying device body  81 . In this case, the rectifying device body  81  is a heat generating portion whose temperature rises near 200° C. by rectification of the chip. Each terminal board  60  has a function as a radiator plate radiating heat generated by the rectifying device body  81 . More specifically, each terminal board  60  is configured to be integral with the radiator plate. 
         [0043]    Both connecting legs  82  are disposed so as to be substantially in parallel to each other. One of the connecting legs  82  has a distal end which is soldered thereby to be connected to the terminal board  60  supporting the rectifying device body  81 , and the other connecting leg  82  has a distal end which is soldered thereby to be connected to the adjacent terminal board  60 . Each terminal board  60  has a side edge on which generally rectangular connection pieces  62  are formed so as to extend widthwise as shown in  FIG. 5 . Each connection piece  62  has a connecting hole  63  through which the distal end of the connecting leg  82  is inserted to be connected thereto by solder. 
         [0044]    Furthermore, a fixing piece  84  is formed on the other side of the rectifying device body  81  so as to protrude widthwise. A screw member  70  is screwed through the fixing piece  84  such that a threaded portion  71  thereof is threadingly engaged with a screw hole  64  formed in each terminal board  60 , whereby the bypass diode  80  is fixed via the screw member  70  to the terminal board  60 . A burring portion  65  having the screw hole  64  is formed on the terminal board  60  so as to protrude downward, as shown in  FIG. 6 . The bottom wall  25  is formed with an escape hole  28  into which the burring portion  65  and the distal end of threaded portion  71  are inserted. The bottom wall  25  is further formed with a stepped thicker wall part  29  having an escape hole  28 , and the terminal board  60  is formed with a stepped portion  66  which is bent along an outer surface of the thicker wall part  29  into the shape of a mounting. 
         [0045]    Paired right and left barrels  67  are formed on the rear ends of the both cable connecting terminals  60 A so as to protrude, respectively. The barrels  67  are crimped onto core wires  91  exposed at terminals of the cables  90  thereby to be connected to the core wires  91 , respectively. When the cable connecting terminals  60 A are connected to the respective cables  90 , the terminals of the cables  90  are adapted to be placed on the stages  16  and anvils (not shown) are inserted into the through holes  17  of the stages  16  from below, and furthermore, a crimper (not shown) is lowered from above such that the barrel  67  holds the core wire  91  between the crimper and the anvil. 
         [0046]    Each cable connecting terminals  60 A have substantially the same surface area as each other, and the right relay connecting terminal  60 B has the largest surface area of all terminal boards  60  as viewed in the drawings. The left relay connecting terminal  60 B has the smallest surface area of all terminal boards  60  in the drawings. Since no rectifying device body  81  of the bypass diode  80  is supported on the left relay connecting terminal  60 B as viewed in the drawings, the left relay connecting terminal  60 B has the smallest surface area. The surface area of the adjacent right relay connecting terminal  60 B is accordingly increased such that radiating performance of the right relay connecting terminal  60 B is improved and a space efficiency is improved. A generally rectangular locking hole  68  is formed in the widthwise middle of the rear end of the right relay connecting terminal  60 B so as to be open as viewed in the drawings. The lock protrusion  19  of the locking piece  18  is elastically fitted in the locking hole  68 . 
         [0047]    A plurality of slits  69  is formed in the relay connecting terminal  60 B. The slits  69  are bent from the root of the connecting piece  62  into a crank shape. The provision of the slits  69  prevents thermal interference between the bypass diodes supported on the respective terminal boards  60 . Furthermore, the bypass diodes  80  are disposed in a zigzag arrangement in the widthwise direction in order to avoid thermal interference thereamong. More specifically, the bypass diode  80  supported on the relay connecting terminal  60 B is disposed frontward relative to the bypass diodes  80  supported on the respective cable connecting terminals  60 A. 
         [0048]    A plurality of bridges  31  is formed so as to widthwise extend across the upper surfaces of the terminal boards  60 . The bridges  31  are formed into the shape of a narrow band and extend together from the upper surface of the bottom wall  25 , holding the terminal boards  60  between the bottom wall  25  and themselves. The bridges  31  include independent board coverage bridges  31 A each bridging the respective terminal boards  60  and full-coverage bridges  31 B each bridging all the terminal boards  60  together. The full-coverage bridges  31 B are located in the rear of the independent board coverage bridges  31 A and extend substantially entire width of the bottom wall  25 . 
         [0049]    Furthermore, the bottom wall  25  is disposed between the rectifying device body  81  and the solar cell module and is closely adhered to the underside of the terminal boards  60  without covering the barrels  67  of the cable connecting terminals  60 A, the burring portion  65 , the peripheries of the insertion holes  61 , the periphery of the locking hole  68  and the peripheries of the connecting holes  63 , as shown in  FIG. 7 . The bottom wall  25  is divided into three parts for every bypass diode  80 . The part of the bottom wall  25  supporting the central bypass diode  80  has the largest surface area. The bottom wall  25  is located between the terminal boards  60  and the solar cell module, whereby the bottom wall  25  has a function of a heat transfer portion which transfers heat generated by the rectifying device bodies  81  to the solar cell module side. 
         [0050]    Paired right and left slides  32  are formed on the widthwise ends of the bottom wall  25  respectively. As shown in  FIG. 5 , each slide  32  has a rib-like slide body  32 A extending in the front-back direction, a first slide  32 B protruding sideways from a front end of the slide body  32 A and a second slide  32 C located in the rear of the first slide  32 B and protruding sideways from the slide body  32 A. The first slide  32 B is located higher than the second slide  32 C and has an underside having a first engagement surface  32 D which is capable of face-to-face contact with the first engagement support surface  23  of the slide support  22 . The second slide  32 C extends into a slenderer shape than the first slide  32 B and has an upper surface having a second engagement surface  32 E which is capable of face-to-face contact with the second engagement support surface  24  of the slide support  22  as shown in  FIG. 3 . The first and second engagement surfaces  32 D and  32 E are disposed at substantially the same heightwise position. Furthermore, on the upper surface of the bottom wall  25  are formed partition walls  38  separating the terminal boards  60  adjacent to each other. 
         [0051]    A manner of assembling the terminal box and advantageous effects thereof will now be described. Firstly, the terminal boards  60  and the bottom  11  are formed by insert molding with the front ends of the terminal boards  60  being connected to each other, whereupon the unit as shown in  FIGS. 5 to 7  is constructed. Subsequently, the rectifying device bodies  81  of the bypass diodes  80  are placed on the respective terminal boards  60 , and the screw members  70  are threadingly engaged with the screw holes  64  so that the bypass diodes  80  are fixed to the terminal boards  60  respectively. The terminal boards  60  are separated from each other at the front ends on a suitable occasion after the insert molding. Furthermore, soldering is applied to the connecting legs  82  of the bypass diodes  80  inserted into the connecting holes  63  of the terminal boards  60 , thereby connecting the bypass diodes  80  to the terminal boards  60 , respectively. The work for mounting the bypass diodes  80  may be carried out after attachment of the bottom  11  to the outer periphery  12 , which attachment will be described later. 
         [0052]    Subsequently, the bottom  11  (the above-described unit) is inserted into the peripheral wall  14  of the outer periphery  12  from below. In this case, the bottom  11  is located slightly forward relative to a normal position thereof. The bottom  11  is moved rearward in this state so that the first engagement support surfaces  23  of the slide supports  22  are slid on the first engagement surfaces  32 D of the first slides  32 B and so that the second engagement support surfaces  24  of the slide supports  22  are slid on the second engagement surface  32 E of the second slides  32 C, respectively. When the bottom  11  thus reaches the normal attachment position, the rear end of the bottom wall  25  abut against the front end of the rear end  36  of the outer periphery  12  thereby to be stopped, and the locking protrusion  19  is elastically fitted in the locking hole  68  of the relay connecting terminal  60 B with deflection of the locking piece  18 . This limits the movement of the bottom  11  in the front-back direction relative to the outer periphery  12 . Furthermore, when the bottom  11  reaches the normal attachment position, the first engagement surfaces  32 D of the first slides  32 B abut against the first engagement support surfaces  23  of the slide supports  22  respectively, whereby the downward displacement of the bottom  11  relative to the outer periphery is limited (see  FIG. 4 ), and furthermore, the second engagement surfaces  32 E of the second slides  32 C abut against the second engagement support surfaces  24  of the slide supports  22  respectively, whereby the upward movement of the bottom  11  relative to the outer periphery  12  is limited (see  FIG. 3 ). Accordingly, the bottom  11  can be fixed to the outer periphery  12  by a simple operation of sliding the bottom  11  in the peripheral wall  14  of the outer periphery  12 . 
         [0053]    Subsequently, the cables  90  are inserted into the cylindrical portions  15  of the case  10  from the rear respectively, and the barrel portions  67  of the cable connecting terminals  60 A are crimped against the core wires  91  placed on the stages  16  thereby to be connected to the core wires  91 , respectively. Furthermore, water-proof caps  40  each made of a resin are attached so as to stride the cylindrical portions  15  and the cable  90  respectively, thereby sealing the cylindrical portions  15  in a water-tight manner. 
         [0054]    Subsequently, the underside (the flat surface  13 ) of the bottom  11  is closely adhered to the mounting surface of the solar cell module, and the case  10  is fixed to the solar cell module by an adhesive agent, double-sided tape, bolt or the like with the bottom  11  being closely adhered to the solar cell module. In the course of the mounting to the solar cell module, leads connected to electrodes of the solar cell module are drawn through the window opening  27  into the case  10  to be solder-joined to the front ends of the terminal boards  60 . An insulating resin such as silicon resin is poured into the case  10 , and a cover is attached to the case  10  after solidification of the insulating resin. 
         [0055]    Meanwhile, when one or more of the rectifying device bodies  81  of the bypass diodes  80  heat up during service, heat is dissipated from the terminal boards  60  through the bottom  11  to the solar cell module side. In this case, since the bottom  11  is made of PPS (polyphenylene sulfide) that has heat resistance and heat transfer property both superior to the outer periphery  12 , the terminal box can be structured so as to be hard to be subjected to damage due to heat. Accordingly, the bottom  11  can be prevented from plastic deformation due to heat generation of the rectifying device bodies  81 , whereupon the flatness of the underside of the bottom  11  can be retained. Consequently, interposition of air space can be avoided between the underside of the bottom  11  and the mounting surfaces of the bypass diodes  80 , whereupon the performance of heat transfer to the solar cell module side can be improved. 
         [0056]    According to the foregoing embodiment, furthermore, since the bottom  11  of the case  10  composes the heat transfer portion, the case  10  can be mounted to the solar cell module with the terminal boards  60  being placed on the bottom  11 , whereupon the terminal box excels in the mountability. Furthermore, since the slides  32  are slid along the slide supports  22  respectively so that the bottom  11  is slidingly attached along the inner edge of the outer periphery  12 , the bottom  11  and the outer periphery  12  can easily be integrated together. Still furthermore, since the bottom  11  and the terminal boards  60  are integrated together by the insert molding, the terminal boards  60  can reliably be prevented from separation from the bottom  11 . 
         [0057]    Moreover, since the bottom  11  is retained so as not to be externally exposed, the bottom  11  may be made of a material with a low weatherproof performance. This can broaden the range of material selection of the bottom  11 . Additionally, since the bottom  11  is necessarily located at positions opposed to the portions supporting the respective rectifying device bodies  81 , heat generated at the rectifying device bodies  81  is efficiently transferred to the bottom  11 , whereupon more desirable heat transfer property can be realized. 
         [0058]      FIGS. 11 and 12  illustrate a second embodiment of the present invention. The second embodiment differs from the first embodiment in that the terminal boards  60 F and the bottom  11 A are not insert-molded. The second embodiment is the same as the first embodiment in the other respects, and identical or similar parts in the second embodiment are labeled by the same reference symbols as those in the first embodiment. 
         [0059]    Circular mounting holes  59  are formed through the terminal boards  60 F except for the left relay connecting terminal  60 B as viewed in the drawing. A plurality of locking pieces  58  is formed on an opening edge of each mounting hole  59  so as to be circumferentially arranged. Each locking piece  58  is formed into a generally radial shape and is elastically deformable in the vertical direction. 
         [0060]    The bottom wall  25 A of the bottom  11 A has columnar protrusions  39  which are located so as to correspond to the mounting holes  59  respectively. When the terminal boards  60 F are placed on the upper surface of the bottom wall  25 A with the front ends thereof being connected to one another, the protrusions  39  are inserted into the mounting holes  59  from below such that distal ends of the locking pieces  58  bite into outer circumferential surfaces of the protrusions  39  respectively, whereby the terminal boards  60 F can be prevented from separation from the bottom  11 A. Subsequently, the front ends of the terminal boards  60 F are cut off from one another. The second embodiment is the same as the first embodiment in a manner of mounting the bypass diodes  80  to respective terminal boards  60 F, a manner of mounting the bottom  11 A to the outer periphery  12 , a manner of installing the case  10  into the solar cell module, and the like, and accordingly, overlapping description will be eliminated. 
         [0061]    The invention should not be limited by the embodiments described above with reference to the drawings, and the following embodiments encompass the technical scope of the invention: 
         [0062]    The heat transfer portion made of a metal may be interposed between the terminal boards and the solar cell module, instead of the bottom. In this case, it is better that the metal heat transfer portion is provided for every terminal board. This can prevent a short circuit between the terminal boards. 
         [0063]    The heat transfer portion having higher heat resistance than the outer periphery is interposed between the terminal boards and the solar cell module in the foregoing embodiments. However, the heat transfer portion may be configured not to be integrated with the outer periphery. 
         [0064]    The plate members supporting the respective diodes may be configured to be independent of the terminal boards and may be mere heat radiating plates each having no function of the terminal (a connecting portion of an electric circuit). 
         [0065]    Each terminal board may be constituted only by a pair of cable connecting terminals and one bypass diode may be configured to extend between both cable connecting terminals.