Patent Publication Number: US-2013240013-A1

Title: Photovoltaic power generation module, photovoltaic power generation module array, and mobile unit

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119 (a) on Patent Application No. 2012-60902 filed in Japan on Mar. 16, 2012, the entire contents of which are herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a photovoltaic power generation module in which rectangular photovoltaic power generation elements are arranged in parallel, a photovoltaic power generation module array in which such photovoltaic power generation modules are connected, and a mobile unit including such a photovoltaic power generation module. 
     2. Description of the Related Art 
     Solar cells having an elongated cell shape are known, and such solar cells are arranged in parallel in one direction in a solar cell module. In the case where solar cell modules are arranged in parallel in a direction intersecting the lengthwise direction of the solar cell modules such that the lengthwise direction of the solar cell modules and the lengthwise direction of solar cells match, a situation can occur in which the output power of the solar cells and the solar cell modules is reduced due to a shadow caused by a difference between adjacent solar cell modules. 
     As a countermeasure against the shadow, a technique has been proposed in which solar cells are arranged such that the lengthwise direction of the solar cells is parallel to the lengthwise direction of the solar cell module (see, for example, JP 2001-111083A (hereinafter referred to as Patent Document 1)). 
     However, the technique disclosed in Patent Document 1 merely suppresses the influence of the shadow caused by the photovoltaic power generation modules that are simply arranged adjacent to each other, and does not take any measures when a so-called shade falls on the solar cells. For this reason, the technique is problematic in that the influence of the shade on the solar cell modules that use solar cells having an elongated shape is not eliminated. 
     Particularly, for the solar cells (solar cell modules) applied to applications, such as mobile units, in which the shade exerts a large influence, the countermeasure against the shade is the key issue. 
     The present invention has been made under the above circumstances, and it is an object of the present invention to provide a photovoltaic power generation module that suppresses a reduction in the amount of power generation due to the shade and improves power extraction efficiency by including extension wiring that is disposed so as to extend in a short side direction intersecting the long sides of a plurality of rectangular photovoltaic power generation elements arranged such that the long sides of the perimeters of the elements are parallel to each other, the extension wiring connecting every specified number of photovoltaic power generation elements in parallel, and connecting in parallel the photovoltaic power generation elements arranged in parallel in one dimensional direction while the photovoltaic power generation elements are arranged in a distributed manner. 
     Also, it is another object of the present invention to provide a photovoltaic power generation module array that is capable of a large amount of photovoltaic power generation with excellent shade resistance and good power extraction efficiency, by including a plurality of the photovoltaic power generation modules according to the present invention. 
     Also, it is another object of the present invention to provide a mobile unit that suppresses a reduction in the amount of power generation due to the shade, improves power extraction efficiency and is capable of stable photovoltaic power generation even when the mobile unit is moving, by including the photovoltaic power generation module according to the present invention. 
     SUMMARY OF THE INVENTION 
     A photovoltaic power generation module according to the present invention includes: a plurality of rectangular photovoltaic power generation elements that are arranged such that long sides of perimeters of the elements are parallel; and an extension wiring that is extended in a short side direction intersecting the long sides and that interconnects the photovoltaic power generation elements, wherein the extension wiring connects every specified number of the photovoltaic power generation elements in parallel. 
     Accordingly, because the photovoltaic power generation module according to the present invention includes the extension wiring that is disposed so as to extend in a short side direction intersecting the long sides of the photovoltaic power generation elements and that connects every specified number of photovoltaic power generation elements in parallel, the rectangular photovoltaic power generation elements arranged in parallel in one dimensional direction can be connected in parallel while the photovoltaic power generation elements are arranged in a distributed manner, as a result of which a reduction in the amount of power generation due to the shade is suppressed, and power extraction efficiency is improved. 
     Also, in the photovoltaic power generation module according to the present invention, the photovoltaic power generation elements may include a first electrode of a first polarity that is disposed on a first side in the short side direction and a second electrode of a second polarity that is disposed on a second side in the short side direction. 
     Accordingly, in the photovoltaic power generation module according to the present invention, a first electrode having a first polarity and a second electrode having a second polarity are disposed along the extension wiring, and therefore the photovoltaic power generation elements and the extension wiring can be easily connected. 
     Also, in the photovoltaic power generation module according to the present invention, the first electrode and the second electrode may be extended along the long sides respectively. 
     Accordingly, in the photovoltaic power generation module according to the present invention, connection between the extension wiring and the first electrode and connection between the extension wiring and the second electrode can be made easily and reliably. Also, it is possible to easily collect current over a wide range along the long sides. 
     Also, the photovoltaic power generation module according to the present invention may include a series section in which a group of the photovoltaic power generation elements are connected in series. 
     Accordingly, because the photovoltaic power generation module according to the present invention includes a series section in which a group of photovoltaic power generation elements are connected in series, a plurality of series sections can be easily formed along the extension wiring, and thus parallel connection of the series stages of each series section can be easily achieved. 
     Also, in the photovoltaic power generation module according to the present invention, the series section may be formed by the photovoltaic power generation elements that are adjacent to each other. 
     Accordingly, in the photovoltaic power generation module according to the present invention, because the series section is formed by connecting in series a group of photovoltaic power generation elements that are adjacent to each other, it is possible to easily form a plurality of series sections along the extension wiring. 
     Also, in the photovoltaic power generation module according to the present invention, with respect to the photovoltaic power generation elements arranged in the series section, an arrangement order in series stages in the series section and an arrangement order in a layout pattern in the series section may be the same. 
     Accordingly, in the photovoltaic power generation module according to the present invention, with respect to the photovoltaic power generation elements arranged in the series section, an arrangement order in series stages in the series section and an arrangement order in a layout pattern in the series section are matched, and therefore parallel connections between a plurality of series sections along the extension wiring are easily achieved with a simple wiring structure. Also, the photovoltaic power generation elements connected in the same series stage are arranged in a distributed manner, and therefore shade resistance can be reliably improved, and a cost reduction can be achieved. 
     Also, in the photovoltaic power generation module according to the present invention, with respect to the photovoltaic power generation elements arranged in the series section, an arrangement order in series stages in the series section and an arrangement order in a layout pattern in the series section may be different. 
     Accordingly, in the photovoltaic power generation module according to the present invention, with respect to the photovoltaic power generation elements arranged in the series section, an arrangement order in series stages in the series section and an arrangement order in a layout pattern in the series section are made different, and therefore the degree of distribution of the photovoltaic power generation elements that are connected in the same series stage is further improved, and thus the shade resistance is further improved. 
     Also, the photovoltaic power generation module according to the present invention may include cross wiring that interconnects the extension wiring mutually. 
     Accordingly, because the photovoltaic power generation module according to the present invention includes cross wiring that interconnects the extension wiring, the arrangement order in the series stages of the photovoltaic power generation elements arranged in the series sections can be freely set by forming a current path between wires of the extension wiring, as a result of which the degree of distribution of the photovoltaic power generation elements can be improved easily and reliably. 
     Also, a photovoltaic power generation module array according to the present invention includes a plurality of photovoltaic power generation modules, and the photovoltaic power generation modules are photovoltaic power generation modules according to the present invention. 
     Accordingly, because the photovoltaic power generation module array according to the present invention includes a plurality of photovoltaic power generation modules according to the present invention, a large amount of photovoltaic power generation with excellent shade resistance and good power extraction efficiency is possible. 
     Also, in the photovoltaic power generation module array according to the present invention, the photovoltaic power generation modules may be connected in parallel. 
     Accordingly, in the photovoltaic power generation module array according to the present invention, because the photovoltaic power generation modules are connected in parallel, the photovoltaic power generation module array can generate a large current while shade resistance is improved. 
     Also, in the photovoltaic power generation module array according to the present invention, the photovoltaic power generation modules may be connected in series. 
     Accordingly, in the photovoltaic power generation module array according to the present invention, because the photovoltaic power generation modules are connected in series, the photovoltaic power generation module array can generate a high voltage while shade resistance is improved. 
     A mobile unit according to the present invention includes a photovoltaic power generation module in which a plurality of photovoltaic power generation elements are connected, and the photovoltaic power generation module is a photovoltaic power generation module according to the present invention. 
     Accordingly, because the mobile unit according to the present invention incorporates a photovoltaic power generation module according to the present invention, a reduction in the amount of power generation due to the shade is suppressed, and power extraction efficiency is improved, as result of which stable photovoltaic power generation is possible even when the mobile unit is moving. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic plan view schematically showing the relationship between a layout pattern of photovoltaic power generation elements and extension wiring in a photovoltaic power generation module according to Embodiment 1 of the present invention. 
         FIG. 1B  is a schematic connection diagram schematically showing the connection relationship between the photovoltaic power generation elements and the extension wiring in the photovoltaic power generation module shown in  FIG. 1A . 
         FIG. 2A  is a schematic plan view schematically showing a layout pattern in a photovoltaic power generation module according to a conventional configuration for comparison to illustrate the action of the photovoltaic power generation module shown in  FIG. 1A . 
         FIG. 2B  is a schematic diagram of a shade illustrating the state of a shade falling on two types of photovoltaic power generation modules that are compared (a photovoltaic power generation module according to the present invention and a photovoltaic power generation module according to a conventional configuration). 
         FIG. 2C  is a graph showing the output power characteristics of the two types of photovoltaic power generation modules compared in terms of variations in the output power due to the shade. 
         FIG. 3A  is a schematic plan view schematically showing the relationship between a layout pattern of photovoltaic power generation elements and extension wiring in a photovoltaic power generation module according to Embodiment 2 of the present invention. 
         FIG. 3B  is a schematic connection diagram schematically showing the connection relationship between the photovoltaic power generation elements and the extension wiring in the photovoltaic power generation module shown in  FIG. 3A . 
         FIG. 4A  is a schematic plan view schematically showing a connection state (parallel connection) of photovoltaic power generation modules in a photovoltaic power generation module array according to Embodiment 3 of the present invention. 
         FIG. 4B  is a schematic plan view schematically showing a connection state (series connection) of photovoltaic power generation modules in a photovoltaic power generation module array according to Embodiment 3 of the present invention. 
         FIG. 5  is a schematic diagram schematically showing the overall view of a mobile unit according to Embodiment 4 of the present invention. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               1  Photovoltaic power generation module 
               1 A Photovoltaic power generation module array 
               101   p  Mounting unit 
               10 ,  11 , . . . Photovoltaic power generation element 
               20 ,  21 , . . . Extension wiring 
               30 ,  31 ,  32  Series section 
               40 ,  41 , . . . Cross wiring 
               45  Series wiring 
               46  Parallel wiring 
               50  Mobile unit 
               51  Power converting unit 
               52  Power storage unit 
             LS Long side 
             Lsc Effective length 
             Lss Illumination length 
             SH Shade 
             SS Short side 
             T 1  First electrode 
             T 2  Second electrode 
             Xd Short side direction 
           
         
       
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
     Embodiment 1 
     A photovoltaic power generation module  1  according to the present invention will be described with reference to  FIGS. 1A to 2C . 
       FIG. 1A  is a schematic plan view schematically showing the relationship between a layout pattern of photovoltaic power generation elements  10  and extension wiring  20  in a photovoltaic power generation module  1  according to Embodiment 1 of the present invention. 
       FIG. 1B  is a schematic connection diagram schematically showing the connection relationship between the photovoltaic power generation elements  10  and the extension wiring  20  in the photovoltaic power generation module  1  shown in  FIG. 1A . 
     The photovoltaic power generation module  1  according to the present embodiment includes a plurality of photovoltaic power generation elements  10  (namely, for example, photovoltaic power generation elements  11  to  14 , . . . , photovoltaic power generation elements  15  to  18 ) that are arranged such that long sides LS of a perimeter of each rectangular element are parallel, and extension wiring  20  (namely, for example, extension wires  21  to  25 ) extending in a short side direction Xd that is perpendicular to and intersects the long sides LS (in a perpendicular direction) and interconnecting the photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , . . . ). The extension wiring  20  (the extension wire  21 , . . . ) connects the photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , . . . ) in parallel in every specified number of photovoltaic power generation elements. 
     Accordingly, since the photovoltaic power generation module  1  according to the present invention includes the extension wiring  20  (the extension wire  21  and so on) that is disposed so as to extend in the short side direction Xd intersecting the long sides LS of the photovoltaic power generation elements  10  (the photovoltaic power generation element  11  and so on) and that connects the photovoltaic power generation elements  10  (the photovoltaic power generation element  11  and so on) in parallel in every specified number of photovoltaic power generation elements, the rectangular photovoltaic power generation elements  10  (the photovoltaic power generation element  11  and so on) arranged in parallel in one dimensional direction can be connected in parallel in a state in which the photovoltaic power generation elements  10  are arranged in a distributed manner, and therefore the reduction in the amount of power generation due to a shade is suppressed and power extraction efficiency is improved. 
     Hereinafter, the photovoltaic power generation element  11 , the photovoltaic power generation element  12 , and so on may be referred to simply as the photovoltaic power generation elements  10 , where it is unnecessary to make a distinction between them. Also, the extension wire  21 , the extension wire  22 , and so on may be referred to simply as the extension wiring  20  where it is unnecessary to make a distinction between them. 
     The photovoltaic power generation elements  10  are arranged (formed) in a layout pattern in which the long sides LS of each elongated rectangle are parallel. In the case where the photovoltaic power generation elements  10  are formed (arranged) on a light transmitting insulating substrate disposed on the side illuminated by light, the wiring surface (the surface shown in the diagram) with respect to the perimeter of the elements is the back of the light receiving surface, and therefore the extension wiring  20  will not affect the light receiving characteristics of the photovoltaic power generation elements  10 . The photovoltaic power generation elements  10  conform to an elongated cell shape applied to, for example, thin film silicon solar cells, CIGS (Copper Indium Gallium DiSelenide) solar cells, and the like. The photovoltaic power generation elements  10  can also be applied to a crystal substrate solar cell in which the photovoltaic power generation elements  10  are arranged so as to face a light transmitting insulating substrate disposed on the light receiving surface side, or other solar cells. 
     For example, four photovoltaic power generation elements  10  (the photovoltaic power generation elements  11  to  14 ) are arranged in parallel in the short side direction Xd (one dimensional direction) and connected to each other in series, whereby a series section  31  (a series section  30 ) is formed. Likewise, four photovoltaic power generation elements  10  (the photovoltaic power generation elements  15  to  18 ) located in a remote position are arranged in parallel in the short side direction Xd and connected to each other in series, whereby a series section  32  (the series section  30 ) is formed. Hereinafter, the series section  31  and the series section  32  may be referred to simply as the series sections  30 , where it is unnecessary to make a distinction between them. Other series sections  30  are arranged at the same interval between the series section  31  and the series section  32 . 
     The expression “the extension wiring  20  connects every specified number of photovoltaic power generation elements  10  in parallel” means that the interval at which the photovoltaic power generation elements  10  are connected in parallel is specified by the number of photovoltaic power generation elements  10  arranged in the series section  30 , and in the present embodiment, every four photovoltaic power generation elements  10  are connected in parallel. In other words, the photovoltaic power generation element  11  of the series section  31  (the series section  30 ) having four elements in series is connected in parallel to the first one of the photovoltaic power generation elements  10  of the series section  30  disposed next, and also connected in parallel to the photovoltaic power generation element  15 , which is the first photovoltaic power generation element of the nth series section  32 . 
     In the present embodiment, for the sake of facilitating the understanding, a case will be described in which four photovoltaic power generation elements  10  form a series section  30 , but it is also possible to form (dispose) a series section  30  having more series stages by connecting more photovoltaic power generation elements  10  in series, and it is also possible to form (dispose) more series sections  30 . 
     The photovoltaic power generation elements  10  each include a first electrode T 1  of a first polarity (for example, p type) disposed on a first side in the short side direction Xd and a second electrode T 2  of a second polarity (for example, n type) disposed on a second side in the short side direction Xd. Accordingly, in the photovoltaic power generation module  1 , the first electrode T 1  having the first polarity and the second electrode T 2  having the second polarity are disposed along the extension wiring  20 , and therefore the photovoltaic power generation elements  10  and the extension wiring  20  can be easily connected. 
     Connection points of the extension wiring  20  to the first electrodes T 1  are shown as first electrode connection points, and connection points of the extension wiring  20  to the second electrodes T 2  are shown as second electrode connection points. 
     The first electrodes T 1  and the second electrodes T 2  are each extended along the long sides LS. Accordingly, in the photovoltaic power generation module  1 , it is possible to easily and reliably connect the extension wiring  20  (the extension wire  21 , etc.) and the first electrodes T 1 , as well as the extension wiring  20  (the extension wire  21 , etc.) and the second electrodes T 2 . It is also possible to easily collect current over a wide range along the long sides LS. 
     The extension wire  21  is connected to the first electrode T 1  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  15  so as to connect the first electrode T 1  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  15  in parallel. 
     The extension wire  22  is connected to the second electrode T 2  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  12  so as to connect the photovoltaic power generation element  11  and the photovoltaic power generation element  12  in series, and is connected to the second electrode T 2  of the photovoltaic power generation element  15  and the first electrode T 1  of the photovoltaic power generation element  16  so as to connect the photovoltaic power generation element  15  and the photovoltaic power generation element  16  in series. Also, the extension wire  22  connects the second electrode T 2  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  12 , and the second electrode T 2  of the photovoltaic power generation element  15  and the first electrode T 1  of the photovoltaic power generation element  16  in parallel. 
     The extension wire  23  is connected to the second electrode T 2  of the photovoltaic power generation element  12  and the first electrode T 1  of the photovoltaic power generation element  13  so as to connect the photovoltaic power generation element  12  and the photovoltaic power generation element  13  in series, and is connected to the second electrode T 2  of the photovoltaic power generation element  16  and the first electrode T 1  of the photovoltaic power generation element  17  so as to connect photovoltaic power generation element  16  and the photovoltaic power generation element  17  in series. Also, the extension wire  23  connects the second electrode T 2  of the photovoltaic power generation element  12  and the first electrode T 1  of the photovoltaic power generation element  13 , and the second electrode T 2  of the photovoltaic power generation element  16  and the first electrode T 1  of the photovoltaic power generation element  17  in parallel. 
     The extension wire  24  is connected to the second electrode T 2  of the photovoltaic power generation element  13  and the first electrode T 1  of the photovoltaic power generation element  14  so as to connect the photovoltaic power generation element  13  and the photovoltaic power generation element  14  in series, and is connected to the second electrode T 2  of the photovoltaic power generation element  17  and the first electrode T 1  of the photovoltaic power generation element  18  so as to connect the photovoltaic power generation element  17  and the photovoltaic power generation element  18  in series. Also, the extension wire  24  connects the second electrode T 2  of the photovoltaic power generation element  13  and the first electrode T 1  of the photovoltaic power generation element  14 , and the second electrode T 2  of the photovoltaic power generation element  17  and the first electrode T 1  of the photovoltaic power generation element  18  in parallel. 
     The extension wire  25  is connected to the second electrode T 2  of the photovoltaic power generation element  14  and the second electrode T 2  of the photovoltaic power generation element  18  so as to connect the second electrode T 2  of the photovoltaic power generation element  14  and the second electrode T 2  of the photovoltaic power generation element  18  in parallel. 
     Accordingly, the extension wiring  20  connects the photovoltaic power generation element  15  to the photovoltaic power generation element  11  in parallel, connects the photovoltaic power generation element  16  to the photovoltaic power generation element  12  in parallel, connects the photovoltaic power generation element  17  to the photovoltaic power generation element  13  in parallel, and connects the photovoltaic power generation element  18  to the photovoltaic power generation element  14  in parallel. In other words, the extension wiring  20  connects the photovoltaic power generation elements  15  to  18  (the series section  32 ) to the photovoltaic power generation elements  11  to  14  (the series section  31 ) in parallel. 
     The extension wiring  20  connects the photovoltaic power generation elements  11  to  14  in series to form the series section  31  (the series section  30 ), and connects the photovoltaic power generation elements  15  to  18  in series to form the series section  32  (the series section  30 ). Also, the extension wiring  20  connects the photovoltaic power generation elements  10  (the photovoltaic power generation elements  11  to  14 ) of the series section  31  and the photovoltaic power generation elements  10  (the photovoltaic power generation elements  15  to  18 ) of the series section  32  in parallel, and thus the series stages of the series section  31  are respectively connected to the series stages of the series section  32  in parallel. 
     As described above, the photovoltaic power generation module  1  includes series sections  30  (the series section  31 , the series section  32 ), in each of which a group of photovoltaic power generation elements  10  (the photovoltaic power generation elements  11  to  14 , the photovoltaic power generation elements  15  to  18 ) are connected in series. 
     Accordingly, since the photovoltaic power generation module  1  according to the present embodiment includes series sections  30  (the series section  31 , the series section  32 , . . . ), in each of which a group of photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) are connected in series, a plurality of series sections  30  can be easily formed along the extension wiring  20  (the extension wire  21 , etc.), and thus it is possible to easily achieve parallel connections to the series stages in the series sections  30 . 
     As used herein, “a group of photovoltaic power generation elements  10 ” refers to a collection of photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) in which a plurality of photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) that are connected in series form a set of series stages according to the series connections. For the sake of facilitating the understanding,  FIGS. 1A and 3A  show examples using series sections  30  (the series section  31 , the series section  32 ), in each of which four photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) are arranged so as to be adjacent to each other. Also, the photovoltaic power generation elements  10  forming a series section  30  are not necessarily arranged so as to be adjacent to each other, and may be arranged in a distributed manner (see Embodiment 2). 
     In the photovoltaic power generation module  1 , series-parallel connection is used in which n groups of four one-dimensionally arranged and series-connected photovoltaic power generation elements  10  are connected in parallel. The series stages of a series section  30  are connected in parallel to respective series stages of another series section  30  that is connected in parallel to said series section  30 . 
     In other words, in the photovoltaic power generation module  1 , a plurality of series sections  30  are connected in parallel by extension wiring  20 , each series section  30  including a plurality of photovoltaic power generation elements  10  that are connected in series, and the photovoltaic power generation elements  10  that are connected in the same series stage in the plurality of series sections  30  are connected to each other in parallel by the extension wiring  20 . In short, the extension wiring  20  connects every specified number of photovoltaic power generation elements  10  that are arranged spaced apart from each other, and also forms series sections  30 . 
     Note that the extension wiring  20  also connects the photovoltaic power generation elements  10  of other series sections  30  that are not shown, with the same regularity. 
     As described above, in the photovoltaic power generation module  1 , a series section  30  is formed by the photovoltaic power generation elements  10  that are adjacent to each other. With this configuration, in the photovoltaic power generation module  1 , a group of photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) that are adjacent to each other are connected in series, whereby a series section  30  (the series section  31 , the series section  32 ) is formed. Accordingly, a plurality of series sections  30  can be easily formed along extension wiring  20 . 
     The photovoltaic power generation elements  10  according to the present embodiment are arranged in a layout pattern in a series section  31  ( FIG. 1A ), in the order of the photovoltaic power generation element  11 , the photovoltaic power generation element  12 , the photovoltaic power generation element  13 , and the photovoltaic power generation element  14 . The photovoltaic power generation elements  10  are also connected such that the arrangement order in the series stages in the series section  31  ( FIG. 1B ) is the order of the photovoltaic power generation element  11 , the photovoltaic power generation element  12 , the photovoltaic power generation element  13 , and the photovoltaic power generation element  14 . 
     In other words, in the photovoltaic power generation module  1 , with respect to the photovoltaic power generation elements  10  of a series section  30 , the arrangement order in the series stages in the series section  30  and the arrangement order in the layout pattern in the series section  30  are the same. With this configuration, in the photovoltaic power generation module  1 , with respect to the photovoltaic power generation elements  10  of a series section  30 , the arrangement order in the series stages in the series section  30  and the arrangement order in the layout pattern in the series section  30  are matched, and therefore parallel connections between a plurality of series sections  30  along extension wiring  20  can be easily achieved with a simple wiring structure. Also, the photovoltaic power generation elements connected in the same series stage are arranged in a distributed manner, and therefore shade resistance can be reliably improved, and a cost reduction can be achieved. 
     In the photovoltaic power generation module  1  according to the present embodiment, the photovoltaic power generation elements  10  of a series section  30  (the series section  31 ) that is connected in parallel to another series section  30  (the series section  32 ) are equidistantly connected in parallel to the photovoltaic power generation elements  10  of the other series section  30  (the series section  32 ) that are connected in parallel. In other words, the arrangement order of the photovoltaic power generation elements  10  of two series sections  30  that are arranged spaced apart from each other is the same between the two series sections  30 . 
       FIG. 2A  is a schematic plan view schematically showing a layout pattern in a photovoltaic power generation module  101  according to a conventional configuration for comparison to illustrate the action of the photovoltaic power generation module  1  shown in  FIG. 1A . 
     The photovoltaic power generation module  101  includes photovoltaic power generation elements  110 . The photovoltaic power generation elements  110  are formed and arranged in the same manner as the photovoltaic power generation elements  10  of the photovoltaic power generation module  1 . 
     However, unlike the photovoltaic power generation elements  10 , the photovoltaic power generation elements  110  are simply connected in series, and in  FIG. 2A , a string of the photovoltaic power generation elements  110  that are continuously connected in series from the left to the right is formed. 
     For the sake of ease of illustration, series wiring is not shown. The photovoltaic power generation module  101  is integrally mounted on a mounting unit  101   p.    
     The photovoltaic power generation module  101  includes, for example, 280 photovoltaic power generation elements  110  that are connected in series. If it is assumed that each photovoltaic power generation element  110  can provide an output power of 1 V (volt), then, an output power voltage of 280 V can be obtained with 280 elements in series. 
       FIG. 2B  is a schematic diagram of a shade illustrating the state of a shade SH falling on two types of photovoltaic power generation modules that are compared (the photovoltaic power generation module  1  according to the present invention and the photovoltaic power generation module  101  according to a conventional configuration). 
     The photovoltaic power generation elements  110  of the photovoltaic power generation module  101  have long sides LS and short sides SS that are the same as those of the photovoltaic power generation elements  10  of the photovoltaic power generation module  1 , but the wiring state of the photovoltaic power generation elements  10  ( FIG. 1A ,  FIG. 1B ) and that of the photovoltaic power generation element  110  ( FIG. 2A ) are different. As shown in  FIGS. 1A and 1B , series wiring and parallel wiring are performed on the photovoltaic power generation elements  10  by the extension wiring  20 , whereas the photovoltaic power generation elements  110  of the photovoltaic power generation module  101  are sequentially connected in series from the left to the right. 
     In other words, the photovoltaic power generation module  101  has an output power voltage of 280 V, with 280 elements in series, whereas the photovoltaic power generation module  1  includes, for example, seven groups in parallel, each group including 40 elements in series (280 photovoltaic power generation elements  10  in total, or in other words, the number of elements is the same as that of the photovoltaic power generation module  101 ) and thus provides an output power voltage of 40 V. Having seven groups in parallel, the current is 7 times larger than that of the case of 280 elements in series by simple calculation. 
     Here, as shown in the diagram, it is assumed that a shade SH has, for example, an elongated shape similar to the shape of the photovoltaic power generation elements  10 . That is, variations in the output power state are compared assuming an illumination length Lss in the direction of the long sides LS with respect to an effective length Lsc corresponding to the entire length of the long sides LS. In the photovoltaic power generation module  1  according to the present embodiment, the photovoltaic power generation elements  10  have a rectangular shape defined by the long sides LS and the short sides SS, and thus comparison is made assuming that the shade SH has an elongated shape extending along the long sides LS. It is preferable to apply the photovoltaic power generation module  1  to an elongated shade SH from the view point of coping with the reduction of output power, but the present invention is not limited thereto, and the shade may have, for example, a shape that covers the entirety of a series section  30 . The comparison result is shown in  FIG. 2C . 
       FIG. 2C  is a graph showing the output power characteristics of the two types of photovoltaic power generation modules compared in terms of variations in the output power due to the shade SH. 
     The horizontal axis indicates the ratio of the illumination length Lss to the effective length Lsc, specifically, indicates the illuminated state by illumination light, which takes a relative value from 0 to 1. The vertical axis indicates the relative output power (a.u.), which takes a relative value from 0 to 1. 
     The conventional photovoltaic power generation module  101  includes the photovoltaic power generation elements  110  that are simply connected in series, and thus the entire photovoltaic power generation module  101  directly receives the influence of the shade SH. That is, even if the shade SH falls on a single photovoltaic power generation element  110  of the series stages, depending on the condition of the shade SH on the single photovoltaic power generation element  110 , the entire module directly receives the influence of the shade, resulting in characteristics following the ratio “effective length Lsc/illumination length Lss” as indicated by a broken line. 
     In contrast, the photovoltaic power generation elements  10  of the present embodiment are configured into seven groups in parallel, each group including 40 elements in series as described above, and thus the shade SH shown in  FIG. 2B  affects only one of the seven groups in parallel (a single group in parallel, namely, a single series section  30 ). Accordingly, even if the ratio “effective length Lsc/effective length Lsc” is 0, it is possible to obtain an output power corresponding to the output power of six groups in parallel, namely, an output power of about 0.86. That is, with the photovoltaic power generation module  1  according to the present embodiment, the reduction of output power due to the shade SH can be reduced significantly, and thus the photovoltaic power generation module  1  can serve as an effective countermeasure against the shade SH. 
     Embodiment 2 
     A photovoltaic power generation module  1  according to the present embodiment will be described with reference to  FIGS. 3A and 3B . The basic configuration of the photovoltaic power generation module  1  according to the present embodiment is the same as that of the photovoltaic power generation module  1  according to Embodiment 1, and thus the following description will be given primarily focusing on differences by referring to the reference numerals used in the above embodiment. The photovoltaic power generation module  1  according to the present embodiment is configured such that the arrangement order in the layout pattern of the photovoltaic power generation elements  10  of the series sections  30  and the arrangement order (positions in the series stages) of the photovoltaic power generation elements  10  in the series stages constituted by the series sections  30  are different. 
       FIG. 3A  is a schematic plan view schematically showing the relationship between a layout pattern of photovoltaic power generation elements  10  and extension wiring  20  in a photovoltaic power generation module  1  according to Embodiment 2 of the present invention. 
       FIG. 3B  is a schematic connection diagram schematically showing the connection relationship between the photovoltaic power generation elements  10  and the extension wiring  20  in the photovoltaic power generation module  1  shown in  FIG. 3A . 
     The photovoltaic power generation module  1  according to the present embodiment includes a series section  31 , a series section  32 , . . . (a series section  30 ). The series section  31  are formed by photovoltaic power generation elements  11  to  14  that are connected to each other in series, and the series section  32  are formed by photovoltaic power generation elements  15  to  18  that are connected to each other in series. Note that the extension wiring  20  also connects the photovoltaic power generation elements  10  of other series sections  30  that are not shown, with the same regularity. 
     An extension wire  21  is connected to the first electrode T 1  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  18  so as to connect the first electrode T 1  of the photovoltaic power generation element  11  and the first electrode T 1  of the photovoltaic power generation element  18  in parallel. 
     An extension wire  22  is connected to the first electrode T 1  of the photovoltaic power generation element  13  and the first electrode T 1  of the photovoltaic power generation element  15  so as to connect the first electrode T 1  of the photovoltaic power generation element  13  and the first electrode T 1  of the photovoltaic power generation element  15  in parallel. 
     An extension wire  23  is connected to the first electrode T 1  of the photovoltaic power generation element  12  and the first electrode T 1  of the photovoltaic power generation element  16  so as to connect the first electrode T 1  of the photovoltaic power generation element  12  and the first electrode T 1  of the photovoltaic power generation element  16  in parallel. 
     An extension wire  24  is connected to the first electrode T 1  of the photovoltaic power generation element  14  and the first electrode T 1  of the photovoltaic power generation element  17  so as to connect the first electrode T 1  of the photovoltaic power generation element  14  and the first electrode T 1  of the photovoltaic power generation element  17  in parallel. 
     An extension wire  25  is connected to the second electrode T 2  of the photovoltaic power generation element  14  and the second electrode T 2  of the photovoltaic power generation element  17  so as to connect the second electrode T 2  of the photovoltaic power generation element  14  and the second electrode T 2  of the photovoltaic power generation element  17  in parallel. 
     An extension wire  26  is connected to the second electrode T 2  of the photovoltaic power generation element  12  and the second electrode T 2  of the photovoltaic power generation element  16  so as to connect the second electrode T 2  of the photovoltaic power generation element  12  and the second electrode T 2  of the photovoltaic power generation element  16  in parallel. 
     An extension wire  27  is connected to the second electrode T 2  of the photovoltaic power generation element  13  and the second electrode T 2  of the photovoltaic power generation element  15  so as to connect the second electrode T 2  of the photovoltaic power generation element  13  and the second electrode T 2  of the photovoltaic power generation element  15  in parallel. 
     An extension wire  28  is connected to the second electrode T 2  of the photovoltaic power generation element  11  and the second electrode T 2  of the photovoltaic power generation element  18  so as to connect the second electrode T 2  of the photovoltaic power generation element  11  and the second electrode T 2  of the photovoltaic power generation element  18  in parallel. 
     Accordingly, as will be shown next, the extension wiring  20  connects in parallel the photovoltaic power generation elements  11  to  14  of the series section  31  and the photovoltaic power generation elements  15  to  18  of the series section  32  in corresponding series stages. 
     The extension wire  21  and the extension wire  28  connect in parallel the photovoltaic power generation element  11  and the photovoltaic power generation element  18  in every specified number of photovoltaic power generation elements. The photovoltaic power generation element  11  is disposed as the first one (first stage) in the series section  31  (the series section  30 ), and the photovoltaic power generation element  18  is disposed as the fourth one (fourth stage) in the series section  32  (the series section  30 ). 
     The extension wire  22  and the extension wire  27  connect in parallel the photovoltaic power generation element  13  and the photovoltaic power generation element  15  in every specified number of photovoltaic power generation elements. The photovoltaic power generation element  13  is disposed as the third one in the series section  31 , and the photovoltaic power generation element  15  is disposed as the first one in the series section  32 . 
     The extension wire  23  and the extension wire  26  connect in parallel the photovoltaic power generation element  12  and the photovoltaic power generation element  16  in every specified number of photovoltaic power generation elements. The photovoltaic power generation element  12  is disposed as the second one in the series section  31 , and the photovoltaic power generation element  16  is disposed as the second one in the series section  32 . 
     The extension wire  24  and the extension wire  25  connect in parallel the photovoltaic power generation element  14  and the photovoltaic power generation element  17  in every specified number of photovoltaic power generation elements. The photovoltaic power generation element  14  is disposed as the fourth one in the series section  31 , and the photovoltaic power generation element  17  is disposed as the third one in the series section  32 . 
     Also, the photovoltaic power generation module  1  according to the present embodiment includes, in addition to the extension wiring  20 , cross wiring  40  (a cross wire  41 , a cross wire  42 , and a cross wire  43 ). The cross wire  41  connects the extension wire  21  and the extension wire  27 . The cross wire  42  connects the extension wire  22  and the extension wire  26 . The cross wire  43  connects the extension wire  23  and the extension wire  25 . Hereinafter, the cross wire  41 , the cross wire  42 , and the cross wire  43  may be referred to simply as the cross wiring  40 , where it is unnecessary to make a distinction between them. 
     In other words, the extension wiring  20  is interconnected by the cross wiring  40 , and the connection order (the arrangement order in the series stages, or in other words, current path) in the series stages in the series sections  30  is defined by the connection state of the cross wiring  40 . 
     The current path (the arrangement order in the series stages) in the series section  31  is, when indicated by the forward direction of the diode symbols shown in the diagram for the sake of facilitating the understanding, the extension wire  24 →the photovoltaic power generation element  14  (the fourth one from the left of the layout pattern shown in the diagram)→the extension wire  25 →the cross wire  43 →the extension wire  23 →the photovoltaic power generation element  12  (the second one of the same)→the extension wire  26 →the cross wire  42 →photovoltaic power generation element  13  (the third one of the same)→the extension wire  27 →the cross wire  41 →the extension wire  21 →the photovoltaic power generation element  11  (the first one of the same)→the extension wire  28 . 
     The current path (the arrangement order in the series stages) in the series section  32  is, when indicated by the forward direction of the diode symbols shown in the diagram for the sake of facilitating the understanding, the extension wire  24 →the photovoltaic power generation element  17  (the third one from the left of the layout pattern shown in the diagram)→the extension wire  25 →the cross wire  43 →the extension wire  23 →the photovoltaic power generation element  16  (the second one in the layout pattern)→the extension wire  26 →the cross wire  42 →the photovoltaic power generation element  15  (the first one in the layout pattern)→the extension wire  27 →the cross wire  41 →the extension wire  21 →the photovoltaic power generation element  18  (the fourth one in the layout pattern)→the extension wire  28 . 
     The arrangement order in the series stages in the series section  31  is the fourth one, the second one, the third one, and the first one in the arrangement order in the layout pattern, whereas in the series section  32 , the arrangement order in the series stages is the third one, the second one, the first one, and the fourth one in the arrangement order in the layout pattern. 
     In other words, in the photovoltaic power generation module  1  according to the present embodiment, with respect to the photovoltaic power generation elements  10  (the photovoltaic power generation element  11 , etc.) of the series sections  30 , the arrangement order in the series stages in the series sections  30  (the series section  31 , the series section  32 ) and the arrangement order in the layout pattern in the series sections  30  (the series section  31 , the series section  32 ) are different. 
     Accordingly, in the photovoltaic power generation module  1  according to the present embodiment, with respect to the photovoltaic power generation elements  10  arranged in the series sections  30 , the arrangement order in the series stages in the series sections  30  and the arrangement order in the layout pattern in the series sections  30  are made different, and therefore the photovoltaic power generation elements  10  are arranged with a further improved degree of distribution of the photovoltaic power generation elements  10  that are connected in the same series stage, as a result of which shade resistance is further improved. 
     Also, the photovoltaic power generation module  1  according to the present embodiment includes the cross wiring  40  that interconnects the extension wiring  20 . With this configuration, the photovoltaic power generation module  1  includes the cross wiring  40  (the cross wire  41 , etc.) that interconnects the extension wiring  20  (the extension wire  21 , etc.), and therefore the arrangement order in the series stages of the photovoltaic power generation elements  10  in the series sections  30  can be freely set by forming a current path between wires of the extension wiring  20  (the extension wire  21 , etc.), as a result of which the degree of distribution of the photovoltaic power generation elements  10  can be improved easily and reliably. Accordingly, the shade resistance of the photovoltaic power generation module  1  is further improved. 
     In the photovoltaic power generation module  1  according to the present embodiment, the photovoltaic power generation elements  10  of a series section  30  connected in parallel to another series section  30  are connected in parallel to the photovoltaic power generation elements  10  that are connected in parallel in the other series section  30 , at different intervals. In other words, the arrangement order of the photovoltaic power generation elements  10  in the series sections  30  that are arranged spaced apart from each other is different among the series sections  30 . 
     Embodiment 3 
     A photovoltaic power generation module array  1 A according to the present embodiment will be described with reference to  FIGS. 4A and 4B . The photovoltaic power generation module array  1 A according to the present embodiment is a photovoltaic power generation module array in which a plurality of the photovoltaic power generation modules  1  (the photovoltaic power generation elements  10 , the series sections  30 ) according to Embodiment 1 or 2 are connected. The basic configuration thereof is as described above in Embodiments 1 and 2, and thus the following description will be given primarily focusing on differences by referring to the reference numerals used in the above embodiments. 
       FIG. 4A  is a schematic plan view schematically showing a connection state (parallel connection) of photovoltaic power generation modules  1  in a photovoltaic power generation module array  1 A according to Embodiment 3 of the present invention. 
     The photovoltaic power generation module array  1 A includes a plurality of photovoltaic power generation modules  1  that are connected to each other. The photovoltaic power generation module  1  is as described above in Embodiments 1 and 2. Accordingly, the photovoltaic power generation module array  1 A according to the present embodiment includes a plurality of the photovoltaic power generation modules  1  of the present invention, and therefore a large amount of photovoltaic power generation with excellent shade resistance and good power extraction efficiency is possible. 
     In the photovoltaic power generation module array  1 A ( FIG. 4A ), the photovoltaic power generation modules  1  are connected in parallel via parallel wiring  46  disposed (connecting) between modules. Accordingly, because the photovoltaic power generation modules  1  are connected in parallel, the photovoltaic power generation module array  1 A can generate a large current while shade resistance is improved. 
     The parallel wiring  46  is configured to interconnect the extension wiring  20  in parallel. 
       FIG. 4B  is a schematic plan view schematically showing a connection state (series connection) of photovoltaic power generation modules  1  in a photovoltaic power generation module array  1 A according to Embodiment 3 of the present invention. 
     In the photovoltaic power generation module array  1 A shown in  FIG. 4A , because the photovoltaic power generation modules  1  are connected in parallel, a situation can occur in which the current capacity becomes large. Accordingly, a large current flows through a connection section (power cable section), and therefore a resistance loss caused by the large current may occur. In the case where it is necessary to avoid the resistance loss, as shown in  FIG. 4B , the photovoltaic power generation modules  1  can be connected in series. The basic configuration is as shown in  FIG. 4A , and thus the following description will be given primarily focusing on differences. 
     In the photovoltaic power generation module array  1 A ( FIG. 4B ), the photovoltaic power generation modules  1  are connected in series via series wiring  45  disposed (connecting) between modules. Accordingly, because the photovoltaic power generation modules  1  are connected in series, the photovoltaic power generation module array  1 A can generate a high voltage while shade resistance is improved. Also, the current can be lowered due to the high voltage, and therefore the resistance loss in the current path can be reduced. 
     The series wiring  45  is configured to join the entire photovoltaic power generation modules  1  together and connect to the next photovoltaic power generation module  1 . 
     Embodiment 4 
     A mobile unit  50  according to the present embodiment will be described with reference to  FIG. 5 . The mobile unit  50  according to the present embodiment is a mobile unit including the photovoltaic power generation module  1  described in Embodiment 1 or the photovoltaic power generation module array  1 A described in Embodiment 3. The basic configuration is as described above in Embodiment 1 or 3, and thus the following description will be given primarily focusing on differences by referring to the reference numerals used in the above embodiments. 
       FIG. 5  is a schematic diagram schematically showing the overall view of a mobile unit  50  according to Embodiment 4 of the present invention. 
     The mobile unit  50  according to the present embodiment incorporates a photovoltaic power generation module  1  (or a photovoltaic power generation module array  1 A) in which a plurality of photovoltaic power generation elements  10  are connected. In other words, the mobile unit  50  includes a photovoltaic power generation module  1  (or a photovoltaic power generation module array  1 A) according to Embodiment 1 or 3. 
     The power generated by photovoltaic power generation in the photovoltaic power generation module  1  is transmitted to a power converting unit  51 , subjected to an appropriate power conversion, and then stored in, for example, a power storage unit  52 . Alternatively, the power is transmitted to an unshown load (for example, motor) and consumed. 
     With the mobile unit  50 , the state of the shade SH varies with time according to the moving condition of the mobile unit  50 , and thus it is not possible to receive a constant amount of illumination light (sunlight) in a stable manner while the mobile unit is traveling. However, the mobile unit  50  incorporates the photovoltaic power generation module  1  according to Embodiment 1 or the photovoltaic power generation module array  1 A according to Embodiment 3, and therefore the reduction in the amount of power generation due to the shade SH can be prevented. Accordingly, a stable amount of power can be obtained by the photovoltaic power generation module  1  incorporated in the mobile unit, and it is therefore possible to achieve highly reliable and stable movement while securing the power obtained by photovoltaic power generation. 
     The present invention can be embodied in various other forms without departing from the gist or essential characteristics thereof. Therefore, the embodiments described above are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description. Furthermore, all modifications or changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.