Terminal box and solar cell module

A terminal box includes three or more terminal strips to which output lines of a solar cell module are connected and a box body having an accommodating portion for accommodating the three or more terminal strips. The box body includes inlet holes formed in a face of the box body opposing to the solar cell module and configured for allowing insertion of the output lines corresponding respectively to the three or more terminal strips. The three or more terminal strips include at least two first terminal strips of a same polarity and at least one second terminal strip insulated from the first terminal strips and having the opposite polarity to that of the first terminal strips. The two first terminal strips are electrically connected via a connecting portion disposed on a back face side of the second terminal strip disposed between and aside the two first terminal strips.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. Section 119 to Japanese Patent Application No. 2015-093358 filed on Apr. 30, 2015, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a terminal box and a solar cell module to which the terminal box is connected.

RELATED ART

With a solar power generation system, a DC power generated in a plurality of solar cell modules mounted on a roof of a house is converted into an AC power by a power conditioner (inverter) and supplied as such to various electric products. The plurality of solar cell modules are connected in series by an external cable via terminal boxes mounted on back faces of the respective solar cell modules.

Generally, the terminal box is configured such that a positive output line and a negative output line and an output cable of the solar cell module are connected to a plurality of terminal strips that are disposed within a main box with an open top and a bypass diode is provided between the terminal strips.

As shown in Japanese Patent No. 3656391, a terminal box having three terminal strips disposed side by side is known. In this case, e.g. two first terminal strips which are positive pair with a second terminal strip which is negative. When the two first terminal strips are disposed in close proximity, connection therebetween is easy. However, in case a second terminal strip is to be disposed between two first terminal strips, the two first terminal strips will be connected with bypassing the second terminal strip.

Japanese Unexamined Patent Application Publication No. 2001-308361 discloses a solar cell module having a plurality of wiring patterns in a terminal box. Between two wiring patterns connected to a negative cable, one wiring pattern connected to a positive cable is disposed and the negative wiring patterns are connected via a jumper line which extends above the positive wiring pattern.

SUMMARY

Within a terminal box, output lines and terminal strips provided in a solar cell module are connected. The output lines are generally mounted and connected on the upper faces of the terminal strips. For this reason, in the case of the arrangement disclosed in the Japanese Unexamined Patent Application Publication No. 2001-308361 where two first terminal strips of a same polarity are connected upwardly of the second terminal strip of the opposite polarity, there can occur an inadvertent contact between the output line connected to the second terminal strip and the interconnecting portion of the two first terminal strips, thus resulting in short circuit between the first terminal strips and the second terminal strip.

According to an embodiment of the present disclosure, there is disclosed a terminal box that allows favorable connection between terminal strips of a same polarity disposed on opposed sides of a terminal strip of the opposite polarity and that also realizes reliable prevention of short circuit with the terminal strip of the opposite polarity.

According to one embodiment of a terminal box relating to the present disclosure, a terminal box comprises:

three or more terminal strips to which output lines for extracting electric power generated by a solar cell module are connected; and

a box body having an accommodating portion for accommodating the three or more terminal strips;

wherein the box body includes inlet holes formed in a face of the box body opposing to the solar cell module and configured for allowing insertion of the output lines corresponding respectively to the three or more terminal strips; and

wherein the three or more terminal strips include at least two first terminal strips of a same polarity and at least one second terminal strip insulated from the first terminal strips and having the opposite polarity to that of the first terminal strips; and

wherein the two first terminal strips are electrically connected via a connecting portion disposed on a back face side of the second terminal strip disposed between and aside the two first terminal strips.

Connection between the output lines of the solar cell module and the terminal strips accommodated in the terminal box is conventionally done on the front face side (upper side) of the terminal strips. On the other hand, according to the above-described arrangement, of the three or more terminal strips provided in the terminal box, the first terminal strips of a same polarity are connected via a connecting portion on the back face side (underneath) of the second terminal strip of the opposite polarity. With this arrangement, unlike the arrangement wherein the terminal strips of a same polarity are connected e.g. along a lateral wall of the box body, the connecting portion will not pose any obstruction when the output lines are to be inserted into the accommodating portion. This connecting portion is connected to the first terminal strips with reliably avoiding accidental contact with the output lines which are connected on the front face side of the second terminal strip. Further, as the connecting portion between the first terminal strips is disposed on the back face side of the second terminal strip, a mounting area of the terminal box relative to the solar cell module can be made small, whereby power generation efficiency of the solar cell module can be increased advantageously.

According to one embodiment of the terminal box relating to the present disclosure, the inlet holes are formed outside an occupying area of the three or more terminal strips in the face opposing to the solar cell module.

If the inlet holes were formed within the occupying area of the three or more terminal strips in the face opposing to the solar cell module, the output lines inserted through these inlet holes may sometimes be disposed on the back face side of the second terminal strip. For this reason, since the connecting portion interconnecting the first terminal strips of a same polarity needs to be disposed at a position clear of the inlet holes, the area for disposing the connecting portion would be limited disadvantageously.

On the other hand, if the inlet holes are formed outside an occupying area of the three or more terminal strips in the face opposing to the solar cell module as provided in the above-described arrangement, the connecting portion can be disposed regardless of the positions of the inlet holes, so the freedom in the layout of the connecting portion will be increased advantageously.

According to one embodiment of the terminal box relating to the present disclosure, the terminal box further comprises an insulating portion which is formed integral with the box body and which is interposed between the second terminal strip and the connecting portion along the face opposing to the solar cell module.

With the above-described arrangement, the insulating portion is interposed between the connecting portion and the second terminal strip of the opposite polarity on the back face side thereof. With this, the insulation performance between the second terminal strip and the connecting portion of the first terminal strips is improved.

According to one embodiment of the terminal box relating to the present disclosure, the two first terminal strips and the connecting portion are formed integral.

With the above-described arrangement wherein the two first terminal strips and the connecting portion are formed integral, there is no need for providing separately an arrangement for connecting the two first terminal strips and the connecting portion. Therefore, the connection arrangement of the two first terminal strips can be realized easily. Further, the number of parts or components to constitute the terminal box can be reduced.

According to one embodiment of a solar cell module relating also to the present disclosure, the solar cell module comprises:

output lines for extracting electric power disposed at an edge portion; and

the terminal box according to any one of the above-described arrangements connected to the edge portion.

In the terminal box connected to the output lines provided at the edge portion of the solar cell module, the inlet holes for the output lines are formed at an end portion of the terminal box. On the other hand, the connecting portion of the first terminal strips of a same polarity is disposed on the back face side of the second terminal strip of the opposite polarity. Thus, relative to the output lines to be inserted from the end portion of the box body, the connecting portion of the first terminal strips can be readily spaced apart therefrom within the area of the second terminal strip, so that the two first terminal strips can be connected with disposing the connecting portion thereof being disposed at an appropriate position free from accidental contact with the conductor of the opposite polarity.

Moreover, since the connecting portion of the first terminal strips is disposed on the back face side of the second terminal strip in the terminal box, there occurs no extension/enlargement of the accommodating portion for the terminal strips in the direction along the solar cell module. Consequently, the terminal box can be formed compact.

DESCRIPTION OF EMBODIMENTS

1. Configuration of Terminal Box

Next, an embodiment of a terminal box relating to the present disclosure will be explained with reference to the accompanying drawings. As shown inFIGS. 1-6, a terminal box1includes a box body100, a lid body700, three terminal strips200mounted inside the box body100, a diode400, and output cables500. The box body100and the lid body700are formed of insulating material such as resin, whereas the terminal strips200are formed of a metal such as copper alloy or the like. The box body100is formed like a box having a top opened. The upper opening of the box body100can be closed with the lid body700. Incidentally, in the following discussion, when there arises a need to discriminate the three terminal strips200from each other, two terminal strips200of a same polarity will be referred to as first terminal strips201,203, and a terminal strip200having the opposite polarity to that of the first terminal strips201,203will be referred to as a second terminal strip202, respectively.

The box body100includes an accommodating portion102and a cable holding portion130. The cable holding portion130defines two through holes (not shown). Into these two through holes, the two output cables500of the positive polarity and the negative polarity are inserted and these cables are fixed to the box body100via a cable holder (not shown). In the following discussion, in the box body100, one side thereof where the cable holding portion130is provided will be referred to as “rear side”, the side opposite the rear side will be referred to as the “front side”, the opened side will be referred to as the “upper side” and the side opposite thereto will be referred to the “lower side”, and the direction perpendicular to the front-rear direction and upper-lower direction will be referred to as left-right direction (disposing direction of the terminal strips), respectively.

The accommodating portion102includes a bottom wall110and a lateral wall120extending erect from the circumferential edge of the bottom wall110and surrounding three directions. The bottom wall110is provided on the face opposing to the solar cell module10. The bottom wall110, the lateral wall120and the front-side end wall of the cable holding portion130together delimit an accommodating space140(an example of “space”). With this, the accommodating portion102is formed like a box having an open top. Inside the accommodating space140, the three terminal strips200and the diode400are accommodated. The solar cell module10(seeFIG. 7) includes an output line600for extracting power generated therein. The output line600and the output cables500are electrically connected to the terminal strips200. With these arrangements, electric power generated in the solar cell module10is outputted from the output cables500via the terminal strips200. Incidentally, the configuration of the terminal strips200will be described later. The output line600is a band-like electric terminal as shown inFIGS. 7-9.

As shown inFIG. 3andFIG. 4, on the upper face of the bottom wall110, there are formed a plurality of projections116and pawl portions118, so that the terminal strips200are supported by the projections116and the fixed by the pawl portions118. That is, the terminal strips200are spaced apart from the upper face of the bottom wall110by an amount corresponding to the height of the projections116.

As shown inFIG. 1, in the bottom wall110, there are formed flange portions150which extend outward from the front and left and right side walls120. In the front side flange portion151, there are provided guiding portions170which will be described later. The left and right flange portions152are provided at intermediate portions in the front-rear direction of the lateral wall120. Further, for improvement of the strength of these flange portions152, ribs160extending in the left-right direction are provided forwardly, centrally and rearwardly of the flange portions152. Further, adjacent the upper end portions of the left and right side walls120, there are provided two retaining holes122respectively for the lid body700.

As shown inFIG. 1, the lid body700is a flat plate-like member for closing the upper opening of the accommodating portion102. The shape of the lid body700is adapted to the planar-viewed shape of the accommodating portion102and this, in this embodiment, is an approximately rectangular shape. In the terminal box1of the instant embodiment, the lid body700constitutes the upper (top) wall of the terminal box1.

The left and right side walls of the lid body700respectively include two retaining pawls702projecting laterally. These retaining pawls702are to be engaged into the retaining holes122defined in the lateral wall120. With this, the lid body700is retained and fixed relative to the box body100.

Of the three terminal strips200disposed side by side in the accommodating portion102, the two first terminal strips201,203disposed on the opposed sides are both terminal strips200of the positive polarity, whereas the second terminal strip202disposed centrally thereof is the terminal strip200of the negative polarity. The first terminal strips201,203are insulated from the second terminal strip202. Whereas, the first terminal strips201,203are electrically conducted to each other via a connecting portion210which will be described later. To the first terminal strip201, the output cable500of the positive polarity is connected. To the second terminal strip202, the output cable500of the negative polarity is connected. Whereas, the first terminal strip203has no connecting portion to be connected to the output cable500of the positive polarity.

As shown inFIG. 3, the terminal strips200respectively include a mounting portion220, an opening230, and a pivot holding portion240. The first terminal strip201and the second terminal strip202respectively further include a diode connecting portion250and a cable connecting portion260. The mounting portion220is a flat face having a predetermined area, on which the leading end of the output line600is to be mounted for ensuring electrical connection with the terminal strip200.

The two first terminal strips201,203are electrically connected to each other via the connecting portion210. This connecting portion210includes a connecting portion body211and raised portions212.

The connecting portion body211is a flat plate having a rectangular shape. And, opposed right/left ends of this connecting portion body211, the raised portions212are formed erect. To the upper ends of the raised portions212, the two first terminal strips201,203are connected. In the instant embodiment, the two first terminal strips201,203and the connecting portion210are formed integral.

As shown inFIG. 2andFIG. 4, the bottom wall110defines an opening113into which the connecting portion body211is to be inserted. In the bottom wall110, downwardly of the second terminal strip202, there is disposed a rectangular-shaped closing body111(an example of “insulator”) for covering the rear portion of the opening113. The closing body111is formed integral with the bottom wall110of the box body100. This closing body111is disposed with keeping the left and right sides of the opening113open and groove portions114are formed adjacent the left and right sides of the closing body111. The closing body111and the opening113together form a recess115on the back face side of the bottom wall110.

The connecting portion body211formed integral with the two first terminal strips201,203will be inserted into the opening113from the accommodating space140. Thereafter, as the raised portions212are guided to the groove portions114and the connecting portion body211is moved rearwards along the bottom wall110, the connecting portion body211will be disposed within the recess115. Since the first terminal strips201,203are mounted on the projections116. Then, the second terminal strip202will be placed on the projection116between the first terminal strips201,203. The connecting portion body211is disposed on the back side of the second terminal strip202across the closing body111. That is, the closing body111is disposed between the second terminal strip202and the connecting portion body211along the bottom wall110.

With the above-described arrangements, unlike e.g. the arrangement of the first terminal strips201,203of a same polarity being connected to each other along the lateral wall120of the box body100, the connecting portion210will pose no obstruction when the output line600is to be inserted into the accommodating portion102. The connecting portion210is connected to the first terminal strips201,203of the positive polarity, with reliable avoidance of contact with the output line600connected on the front face side of the second terminal strip202of the negative polarity. Further, as the connecting portion210is located on the back face side of the second terminal strip202, the mounting area of the terminal box1relative to the solar cell module10can be reduced, such that power generation efficiency of the solar cell module10can be increased.

Between the second terminal strip202and the connecting portion body211, the closing body111is present. With this, the insulation performance between the second terminal strip202of the negative polarity and the connecting body portion211of the positive polarity is improved. Further, the connecting portion body211is disposed within the recess115, not to protrude from the back face side of the bottom wall110. Therefore, the terminal box1can be mounted with the bottom wall110being aligned with the solar cell module10.

Rearwardly of the opening230of the terminal strip200, the pivot holding portion240is provided. After the leading end of the output line600is placed upwardly of the opening230, the pivot holding portion240will be folded toward the opening230, thereby to fix the output line600.

As shown inFIG. 3andFIG. 4, in the pivot holding portion240, a support portion242is formed of two bridges extending in the front-rear direction. Forwardly of the support portion242, there is formed a pivot portion241which is vertically pivotable about the support portion242and has a flat face. That is, the pivot holding portion240is configured like a cantilever beam whose end is fixed to the support portion242. With this, the pivot portion241can be displaced with the support portion242acting as the pivot therefor. The pivot portion241is slanted upwards around the support portion242relative to the mounting portion220so that the opening230is kept opened under the initial state. The pivot portion241and the support portion242can be shaped to be connected in a discontinuous manner. For instance, the pivot portion241can have a rectangular outer shape and the support portion242can extend from one side thereof. Still alternatively, the outer shape of the pivot portion241can be round.

In the instant embodiment, the opening230has a rectangular shape. Instead, this can be circular. The outer shape of the pivot portion241and the shape of the opening230can be any desired shapes.

Rearwardly of the pivot holding portion240, a diode connecting portion250is formed. This diode connecting portion250and the cable connecting portion260which will be described later are formed only in the first terminal strip201and the second terminal strip202, not being formed in the first terminal strip203. The diode connecting portion250has a slit which is opened in the left-right direction. Into this slit, a terminal402(seeFIG. 3) of the diode400extending in the left-right direction will be press-fitted. With this, the diode400is held with ensuring electric connection between the diode400and the first terminal strip201and the second terminal strip202.

This diode400comprises a bypass diode, which has a function of supplying electric current with bypassing the solar cell module10, when power generation becomes impossible e.g. as a certain solar cell module10enters a shade. With this arrangement, reduction in power generation efficiency of the whole system with the solar cell module10incapable of power generation providing electric load thereto is prevented.

The cable connecting portion260has a U-shaped cross section which is formed when the terminal strip200is cut along the left-right direction, and on and at this portion, a core wire502of the output cable500will be placed. And, as the core wire502is calked as being surrounded by the U-shaped portion, electric connection between the terminal strip200and the output cable500is secured.

As shown inFIG. 2, in the front side flange portion151of the box body100, three tab inlet holes112each having a rectangular shape are formed. These three tab inlet holes112are formed as through holes and disposed side by side in the left-right direction. As shown inFIG. 2andFIG. 6, the tab inlet holes112are formed on the outer side of the accommodating portion102in the face opposing to the solar cell module10. Incidentally, the tab inlet holes112can be formed partially on the inner side of the accommodating portion102.

As shown inFIGS. 6-8, on the side of the lateral wall120opposing to the tab inlet holes112, there is formed the guiding portion170which guides the output line600inserted into the tab inlet hole112toward the terminal strip200. This guiding portion170is provided between the tab inlet hole112and an opening121formed in the front side lateral wall120so that the outside of the box body100and the accommodating space140are communicated with each other. The guiding portion170is constituted of a guiding face171opposing to the tab inlet hole112and side portions172on the opposed sides of the guiding portion171(seeFIG. 1). With this, the output line600inserted into the tab inlet hole112will be introduced into the accommodating space140via the guiding portion170. Incidentally, the tab inlet hole112is an example of “inlet hole”.

In the above, the guiding face171has a sloped portion173which is sloped in a direction away from the tab inlet hole112as approaching the terminal strip200. The sloped portion173is present at least at a portion of the guiding face171. The output line600introduced through the tab inlet hole112will come into contact with the sloped portion173, thus being gently bent and guided toward the terminal strip200.

The guiding face171is formed, with portions of the side walls120protruding outside the accommodating portion102. In this way, as the guiding face171is disposed on the outer side of the accommodating portion102, there is no need for providing the accommodating space140with a space dedicated to the guiding face171. As a result, the accommodating space102can be formed compact, and an amount of bonding agent to be introduced into the accommodating portion102can be restricted advantageously.

The guiding face171is provided at a position lower than a top T of the side walls120. The terminal box1, as shown inFIG. 7,FIG. 8andFIG. 10, will be connected to the solar cell module10with the output line600being provided at its edge portion11, for instance. In the course of handling of the solar cell module10, the box body100of the terminal box1connected to the edge portion11of the solar cell module10will be particularly susceptible to a shock as its vertical end portion coming into contact with a foreign object.

However, as the guiding face171is provided at the position lower than the top T of the side walls120as provided in the instant embodiment, as shown inFIG. 10, the amount of upward projection of the guiding portion170which forms the edge of the terminal box1can be restricted in the edge portion11of the solar cell module10. Thus, accidental contact between the guiding portion170of the terminal box1and a foreign object will be made less likely to occur. Further, the volume of the area between the guiding face171and the tab inlet hole112is reduced, to that the amount of bonding agent to be introduced into the accommodating portion102of the box body100can be reduced advantageously.

2. Connecting Procedure of Output Lines

Next, with reference to the accompanying drawings, there will be explained a procedure of connecting the output line600of the solar cell module10to the terminal strip200inside the box body100.

When the output line600is to be connected to the terminal strip200, firstly, the output line600will be inserted through the tab inlet hole112, with keeping the pivot holding portion240under an open posture like the second terminal strip202as shown inFIG. 7. Then, the output line600will come into contact with the guiding face171and bent along this face, thus being guided into the accommodating space140from the outer side of the accommodating portion102. Then, the leading end portion of the output line600will be positioned upwardly of the opening230of the terminal strip200(seeFIG. 8).

Next, by a tool such as a minus driver or the like, or a jig, the pivot portion241of the pivot holding portion240will be pivoted about the support portion242acting as the pivot, thus being moved downwards in the closing direction of the opening230. Namely, the pivot holding portion240will be moved from the open posture to the fixed posture. When the pivot holding portion240assumes the fixed posture, the output line600will be sandwiched and fixed between the opening230and the pivot holding portion240of the terminal strip200. With this, the output line600is electrically connected to the terminal strip200(seeFIG. 9).

As described above, the output line600inserted toward the guiding portion170via the tab inlet hole112on the outer side of the accommodating portion102will be guided toward the terminal strip200by the guiding face171provided in the terminal box1. With this, an assembly operation of assembling the output line600to the terminal strip200can be readily carried out. Further, as a portion of the guiding face171is sloped in the direction away from the tab inlet112as approaching the terminal strip200, the output line600coming into contact with the guiding face171will be bent gently toward the terminal strip200. Thus, the output line600can be guided toward the terminal strip200without giving stress on this output line600.

(1) In the foregoing embodiment, there was shown an example wherein the closing body111as the bottom wall110is present between the connecting portion body211and the second terminal strip202. However, it is also possible to employ an arrangement of no bottom wall110being present between the connecting portion body211and the second terminal strip202.

(2) In the foregoing embodiment, there was shown an example wherein the two first terminal strips201,203and the connecting portion210are formed integral each other. Alternatively, the connecting portion210may be formed integral with only one of the two first terminal strips201,203. Still alternatively, as shown inFIG. 11, the connecting portion210may be constituted of a member separate from the first terminal strips201,203. In this case, as shown inFIG. 11for instance, the two members will be connected to each other via an engaging portion213(e.g. an engaging projection portion) provided in the raised portion212and an engaged portion205(e.g. an engaging hole portion) provided in the first terminal stripe201,203. In the case of this connecting portion210constituted of a member separate from the first terminal strips201,203, for instance, only the groove portions114may be provided in the bottom wall110; and after the first terminal strips201,203are fixed to the projections116, from the back face side of the bottom wall110, the connecting portion210may be connected to the first terminal strips201,203via the groove portions114.

(3) In the foregoing embodiment, there was shown an example wherein the connecting portion210of the two first terminal strips201,203includes the flat-plate like connecting portion body211and the raised portions212. Alternatively, the connecting portion210may have other shape as long as such other shape too establishes electric conduction of the two first terminal strips201,203.