Abstract:
In a photovoltaic solar cell module assembly of the present invention, a plurality of photovoltaic solar cell modules that receive light irradiation and generate a predetermined power output are connected in series, and each of positive and negative electrodes located on both ends of a row of the series-connected photovoltaic solar cell modules is bifurcated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This is a Continuation Application of PCT Application No. PCT/JP03/00205, filed Jan. 14, 2003, which was published under PCT Article 21(2) in Japanese. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a photovoltaic solar cell module assembly and a wiring system thereof, and a photovoltaic power system.  
         [0004]     2. Description of the Related Art  
         [0005]     In general, an operating voltage of a photovoltaic solar cell module is lower than that of a power conditioner. Thus, a plurality of photovoltaic solar cell modules are connected to a power conditioner after connected in series. If the number of photovoltaic solar cell modules is increased, a plurality of series connections (cell arrays) are made and wiring which connects the cell arrays in parallel is connected to the power conditioner.  
         [0006]     In fact, when a photovoltaic power system is installed, integer n that is close to the number obtained by dividing the operating voltage (for example, 200V) of the power conditioner by the operating voltage of the photovoltaic solar cell modules is first selected. The integer n is handled as the number of the photovoltaic solar cell modules in series connection. Next, the number n of the modules in series connection is multiplied by power output Vo of the photovoltaic solar cell modules to obtain a product. The product (n×Vo) is equivalent to the power output of a single row. Next, integer m that is close to the number obtained by dividing the power output of the photovoltaic power system by the power output (n×Vo) of the single row is selected. The integer m is handled as the number of cell arrays in parallel connection.  
         [0007]     A conventional photovoltaic solar cell module  2  comprises a terminal box  6  whose back surface is attached thereto, a pair of cables  4   a  and  4   b  connected respectively to positive and negative terminals inside the terminal box  6 , and male and female connectors  3   a  and  3   b  attached respectively to distal ends of the cables  4   a  and  4   b , as shown in  FIG. 7 .  
         [0008]     The female connector  3   b  has a contact element  35  at the deepest portion in a hole of an insulation guide  31  as shown in  FIG. 8A . The male connector  3   a  has a pin  32  in a hollow portion of an insulation guide  33  as shown in  FIG. 8B . When the male connector  3   a  is inserted into the female connector  3   b , a distal end of the pin  32  is fitted in a recess of the contact element  35  and both the connectors thereby become conductive as shown in  FIG. 8C .  
         [0009]     In the conventional photovoltaic power system, as shown in  FIG. 11 , the power generated in a plurality of photovoltaic solar cell modules  2  is collected to positive and negative terminals  16  in a junction box  17  by extension cables  18  and  19 , output from the junction box  17  to a power conditioner  20  by a connecting cable  21 . In the power conditioner  20 , the DC power is converted into the AC power, which is fed to each of electric devices.  
         [0010]     Incidentally, when the conventional system is installed, the number of series connection of photovoltaic solar cell modules  2  and the number of parallel connection thereof are designed, and members of the extension cables  18 ,  19  and the like whose number corresponds to the number of modules are prepared. The photovoltaic solar cell modules  2  are connected while the number of modules in series connection is counted at the installation place. When the wiring connection of a single row of the modules is completed, the extension cables  18  and  19  are connected to both side ends of the modules. The extension cables  18  and  19  are connected parallel at the positive and negative terminals  16  inside the junction box  17 .  
         [0011]     In the conventional system, however, if each of the photovoltaic solar cell modules is small in area and power output similarly to a roofing tile-integrated photovoltaic solar cell module, the number of photovoltaic solar cell modules is increased, the number of a row of photovoltaic solar cell modules is also increased, and errors easily occur in counting the number of modules in series connection.  
         [0012]     In addition, particularly, since steps of the expensive and dangerous rooftop operation are increased, installation costs are increased. For this reason, simplifying the design of wiring connection of the photovoltaic solar cell modules, improving installation operability at the installation place (on the roof) and reducing the operation steps are important problems.  
       BRIEF SUMMARY OF THE INVENTION  
       [0013]     The present invention has been accomplished to solve the above-described problems. The object of the present invention is to provide a photovoltaic solar cell module assembly, a wiring system and a photovoltaic power system, capable of facilitating the wiring connection of photovoltaic solar cell modules.  
         [0014]     A photovoltaic solar cell module assembly according to the present invention is characterized by connecting in series a plurality of photovoltaic solar cell modules that receive light irradiation and generate predetermined power output and by bifurcating each of positive and negative electrodes located on both ends of a row of the series-connected photovoltaic solar cell modules.  
         [0015]     The wiring system in which a plurality of photovoltaic solar cell module assemblies are connected in parallel is formed by connecting the positive electrodes of the adjacent photovoltaic solar cell module assemblies to each other and the negative electrodes thereof to each other.  
         [0016]     In this case, it is preferable that the photovoltaic solar cell modules should be integral with the base members (roofing tiles, construction materials and the like).  
         [0017]     By connecting a plurality of photovoltaic solar cell module assemblies in parallel, a photovoltaic power system whose operating voltage is set to be substantially equal to a power conditioner operating voltage or to be an operating voltage that is an integral submultiple of the power conditioner operating voltage is formed.  
         [0018]     In the present invention, the photovoltaic solar cell module assemblies capable of generating an operating voltage corresponding to the operating voltage of the power conditioner by preliminarily connecting a plurality of photovoltaic solar cell modules in series are prepared, and the photovoltaic power system is formed by connecting the photovoltaic solar cell module assemblies in parallel.  
         [0019]     According to the present invention, it is unnecessary to install the photovoltaic solar cell modules while counting the number of modules in series connection at the installation place or connect the photovoltaic solar cell modules in parallel at the installation place. For this reason, design in wiring connection of the photovoltaic solar cell modules can be simplified and the installation operability at the installation place can also be improved.  
         [0020]     The photovoltaic solar cell module assembly according to the present invention is characterized in that a plurality of photovoltaic solar cell modules are connected in series and that each of positive and negative electrodes on both ends of the series-connected photovoltaic solar cell modules is bifurcated. This photovoltaic solar cell module assembly is connected in parallel with the adjacent photovoltaic solar cell module assembly by connecting their positive electrodes to each other and their negative electrodes to each other.  
         [0021]     The photovoltaic solar cell modules inside the photovoltaic solar cell module assembly may be connected in series via connectors attached to distal ends of the cables led from the junction box or the junction boxes may be connected directly with cables. Each of positive and negative electrodes on both ends of the photovoltaic solar cell module assembly is bifurcated, cables are connected to the respective bifurcated electrodes, and a connector is attached to the distal end of each cable to form two pairs of positive and negative electrode terminals. The positive and negative electrode terminals may be grouped into two sets of paired positive and negative electrodes, the connectors may be attached to the distal ends of the cables, the distal ends of the cables may be tied while insulated from each other, or the connectors at the distal ends may be integrated while insulated from each other.  
         [0022]     Furthermore, it is preferable that a backflow preventing diode should be provided inside the single photovoltaic solar cell module assembly.  
         [0023]     The photovoltaic power system according to the present invention comprises at least a power conditioner and a photovoltaic solar cell module assembly whose operating voltage corresponds to the operating voltage of the power conditioner by preliminarily connecting a plurality of photovoltaic solar cell modules in series. The photovoltaic power system is characterized in that each of the positive and negative electrodes on both ends of the assembly is bifurcated and that the adjacent photovoltaic solar cell module assemblies are connected in parallel by connecting the positive electrodes thereof to each other and the negative electrodes thereof to each other.  
         [0024]     The cell element of the photovoltaic solar cell module used in the present invention is not limited particularly, but may be any silicon-based or compound-based element. The silicon may be any one of polycrystalline silicon, monocrystalline silicon, an amorphous silicon thin film, a microcrystalline silicon thin film, a monocrystalline silicon thin film, a polycrystalline silicon thin film, and their combination. The crystalline silicon-based photovoltaic solar cell is a photovoltaic solar cell which contains crystalline silicon as its semiconductor material. The present invention can be applied to solar batteries of any kinds that can be classified into monocrystal, polycrystal and microcrystal. The amorphous silicon-based photovoltaic solar cell is a photovoltaic solar cell which contains amorphous silicon as its semiconductor material. The compound-based photovoltaic solar cell is a photovoltaic solar cell which contains garium arsenide (GaAs), CuInSe 2  called CIS base, and the like, as its semiconductor material.  
         [0025]     According to the present invention, since it is unnecessary to install the photovoltaic solar cell modules while counting the number of modules in series connection at the installation place, errors in wiring are not generated due to errors in counting.  
         [0026]     In addition, since the photovoltaic solar cell module assemblies have only to be connected in parallel at the installation place, the number of installation steps at the installation place is reduced, dangerous rooftop wiring operations are simplified, and the installation costs are remarkably reduced. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0027]      FIG. 1A  is a perspective view of a photovoltaic solar cell module assembly according to an embodiment of the present invention as seen from a top surface side thereof;  
         [0028]      FIG. 1B  is a perspective view of the photovoltaic solar cell module assembly as seen from a back surface side thereof;  
         [0029]      FIG. 2A  is a perspective view of a photovoltaic solar cell module assembly according to another embodiment of the present invention as seen from a top surface side thereof;  
         [0030]      FIG. 2B  is a perspective view of the photovoltaic solar cell module assembly according to another embodiment as seen from a back surface side thereof;  
         [0031]      FIG. 3  is a perspective view of a photovoltaic solar cell module arranged at an end portion of the photovoltaic solar cell module assembly;  
         [0032]      FIG. 4  is a perspective view of a photovoltaic solar cell module arranged at a portion (middle portion) other than the end portion of the photovoltaic solar cell module assembly;  
         [0033]      FIG. 5  is a perspective view of an installation example of tying negative and positive electrode cables;  
         [0034]      FIG. 6  is a perspective view of another installation example of tying negative and positive electrode cables;  
         [0035]      FIG. 7  is a perspective view showing a conventional photovoltaic solar cell module and connectors of a trunk side (extension cable side);  
         [0036]      FIG. 8A  is a cross-sectional view of a female connector (of negative side);  
         [0037]      FIG. 8B  is a cross-sectional view of a male connector (of positive side);  
         [0038]      FIG. 8C  is a cross-sectional view of connection of the male and female connectors;  
         [0039]      FIG. 9A  is a circuit diagram pictorially showing a photovoltaic solar cell module assembly;  
         [0040]      FIG. 9B  is a circuit diagram pictorially showing another photovoltaic solar cell module assembly;  
         [0041]      FIG. 9C  is a circuit diagram pictorially showing still another photovoltaic solar cell module assembly;  
         [0042]      FIG. 9D  is a circuit diagram pictorially showing a photovoltaic power system;  
         [0043]      FIG. 10A  is a circuit diagram showing a photovoltaic solar cell module assembly according to still another embodiment;  
         [0044]      FIG. 10B  is a circuit diagram showing a photovoltaic solar cell module assembly according to still another embodiment;  
         [0045]      FIG. 10C  is a circuit diagram showing a photovoltaic solar cell module assembly according to still another embodiment; and  
         [0046]      FIG. 11  is a block diagram showing a conventional photovoltaic power system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0047]     Embodiments of the present invention will be explained below with reference to the accompanying drawings.  
         [0048]     (First Embodiment)  
         [0049]      FIGS. 1A and 1B  schematically show an example of a photovoltaic solar cell module assembly employed in a photovoltaic power system in which an operating voltage for each photovoltaic solar cell module is 50V and an operating voltage of a power conditioner is 200V. In a photovoltaic solar cell module assembly  1 A of the first embodiment, four photovoltaic solar cell modules  2  are aligned on a common base member  10  as shown in  FIG. 1A  and connected in series as shown in  FIG. 1B . Each of positive and negative terminals of both side ends is bifurcated. In other words, the positive terminal and the negative terminal inside a terminal box  6 , of the adjacent photovoltaic solar cell modules  2 , are connected in series by an inter-module coupling cable  6  and connectors. The bifurcated positive electrode cables  4   a  are connected to the positive terminal on a one-side end of the row of modules and the bifurcated negative electrode cables  4   b  are connected to the negative terminal on the other side end of the row of modules.  
         [0050]     Connectors  3   a  are attached to distal ends of the bifurcated cables  4   a , respectively, and connectors  3   b  are attached to distal ends of the bifurcated cables  4   b , respectively. The connectors can be further connected to the other photovoltaic solar cell module assembly  1 A.  
         [0051]     The material of the base member  10  may be any one of ceramic, resin and metal. The base member  10  itself may be a roof tile, an instruction member or the like.  
         [0052]     In the current home photovoltaic power system, the output voltage of the photovoltaic solar cell, i.e. the input voltage of the power conditioner needs to be approximately 200V. If the voltage of each of currently available photovoltaic solar cell modules is, for example, 50V, which depends on the module size, four cell modules  2 G need to be connected in series as shown in  FIG. 9C  to obtain the output voltage of 200V corresponding to the power conditioner operating voltage of 200V.  
         [0053]     Moreover, positive electrodes of adjacent photovoltaic solar cell module assemblies  1 G having the output voltage of 200V are connected with the extension cables  18  and negative electrodes of adjacent photovoltaic solar cell module assemblies  1 G are connected with the extension cables  19 . Thus, a photovoltaic power system in which the photovoltaic solar cell module assemblies  1 G having the output voltage of 200V are connected in parallel can be configured as shown in  FIG. 9D .  
         [0054]     In this method of wiring connection, the time of the rooftop operations is remarkably reduced and the installation is simplified.  
         [0055]     (Second Embodiment)  
         [0056]      FIGS. 2A and 2B  schematically show an example of a photovoltaic solar cell module assembly in a case where an operating voltage for each photovoltaic solar cell module is 100V and a power conditioner operating voltage is 200V. In a photovoltaic solar cell module assembly  1 B of the second embodiment, two photovoltaic solar cell modules  2  are arranged adjacently as shown in  FIG. 2A  and connected in series as shown in  FIG. 2B . A pair of positive and negative terminals are guided from each of the terminal boxes  6  of both side ends. In other words, the positive terminal and the negative terminal inside the terminal boxes  6 , of the adjacent photovoltaic solar cell modules  2 , are connected in series by the inter-module coupling cable  6  and connectors. The bifurcated positive and negative electrode cables  4   a  and  4   b  are connected to the positive and negative terminals on a one-side end of the row of modules and the bifurcated positive and negative electrode cables  4   a  and  4   b  are connected to the positive and negative terminals on the other side end of the row of modules.  
         [0057]     Connectors  3   a  are attached to distal ends of the bifurcated cables  4   a , respectively, and connectors  3   b  are attached to distal ends of the bifurcated cables  4   b , respectively. The connectors can be further connected to the other photovoltaic solar cell module assembly  1 B.  
         [0058]     In the photovoltaic solar cell module assembly of this embodiment, one of the positive electrode cables  3   a  is extended and the positive connector  3   a  thereof is arranged in the vicinity of the negative connector  3   b  of the cable  4   b  of the opposite side.  
         [0059]     In the current home photovoltaic power system, the output voltage of the photovoltaic solar cell, i.e. the input voltage of the power conditioner needs to be approximately 200V. If the voltage of each of currently available photovoltaic solar cell modules is, for example, 100V, which depends on the module size, two cell modules  2 E need to be connected in series as shown in  FIG. 9A  to obtain the output voltage of 200V corresponding to the power conditioner operating voltage of 200V.  
         [0060]     Moreover, positive electrodes of adjacent photovoltaic solar cell module assemblies  1 E having the output voltage of 200V are connected with the extension cables  18  and negative electrodes of adjacent photovoltaic solar cell module assemblies  1 E are connected with the extension cables  19 . Thus, a photovoltaic power system in which the photovoltaic solar cell module assemblies  1 E having the output voltage of 200V are connected in parallel can be configured as shown in  FIG. 9D .  
         [0061]     In this method of wiring connection, the time of the rooftop operations is remarkably reduced and the installation is simplified.  
         [0062]     (Third Embodiment)  
         [0063]     Next, a third embodiment of the present invention will be explained with reference to  FIGS. 3, 4 ,  9 A- 9 D, and  10 A- 10 C.  
         [0064]      FIG. 3  schematically shows a photovoltaic solar cell module arranged at an end portion of the photovoltaic solar cell module assembly.  FIG. 4  schematically shows a photovoltaic solar cell module arranged at a portion (middle portion) other than the end portion of the photovoltaic solar cell module assembly.  
         [0065]     In the photovoltaic solar cell module assembly of this embodiment, photovoltaic solar cell module  2 T shown in  FIG. 3  is arranged on both side ends of the module assembly and photovoltaic solar cell module  2 M shown in  FIG. 4  is arranged at the middle portion of the module assembly. The photovoltaic solar cell modules  2 M are connected with the inter-module coupling cable  5  and the modules  2 T of both sides are connected to the modules  2 M of the middle portion. Thus, the output voltage of 200V corresponding to the power conditioner operating voltage of 200V can be obtained.  
         [0066]     For example, if the operating voltage of each photovoltaic solar cell module is 100V, two photovoltaic solar cell modules are connected in series as shown in  FIGS. 9A and 10A  to correspond to the power conditioner operating voltage of 200V.  
         [0067]     In addition, for example, if the operating voltage of each photovoltaic solar cell module is 67V, three photovoltaic solar cell modules are connected in series as shown in  FIGS. 9B and 10B  to correspond to the power conditioner operating voltage of 200V.  
         [0068]     Moreover, for example, if the operating voltage of each photovoltaic solar cell module is 50V, four photovoltaic solar cell modules are connected in series as shown in  FIGS. 9C and 10C  to correspond to the power conditioner operating voltage of 200V.  
         [0069]     The photovoltaic solar cell module assembly thus configured to have the operating voltage of 200V is connected in parallel with adjacent photovoltaic solar cell module assemblies as shown in  FIG. 9D . In this connecting method, the time of the rooftop operations is remarkably reduced and the installation is simplified.  
         [0070]     (Fourth Embodiment)  
         [0071]     Next, a fourth embodiment of the present invention will be explained with reference to  FIGS. 5 and 6 .  
         [0072]     In a photovoltaic solar cell module assembly  1 C (with the structure substantially equal to that of the module assembly  1 B of the second embodiment) in which two photovoltaic solar cell modules  2  are mounted on the base member  10 , a pair of positive and negative cables  4   a  and  4   b  may be preliminarily tied on the ground with a tie member  8  formed of an adhesive tape and a fastening band, as shown in  FIG. 5 , before bringing the module assembly onto the roof.  
         [0073]     In addition, in a photovoltaic solar cell module assembly  1 D (with the structure substantially equal to that of the module assembly  1 A of the first embodiment) in which four photovoltaic solar cell modules  2  are mounted on the base member  10 , a pair of positive and negative cables  4   a  and  4   b  may be preliminarily tied on the ground with the tie member  8  formed of an adhesive tape and a fastening band, as shown in  FIG. 6 , before bringing the module assembly onto the roof.  
         [0074]     Therefore, the (rooftop) operability is further improved and the installation costs are reduced.  
         [0075]     (Fifth Embodiment)  
         [0076]     Next, a fifth embodiment of the present invention will be explained with reference to  FIGS. 10A  to  10 C.  
         [0077]     In a photovoltaic solar cell module assembly  1 E (with the structure substantially equal to that of the module assembly  1 B of the second embodiment) comprising two photovoltaic solar cell modules  2 E, a backflow preventing diode  55  is inserted into the cable  5  immediately before the positive electrode side of the cable is bifurcated, as shown in  FIG. 10A , to prevent backflow of a DC current generated in the modules  2 E.  
         [0078]     In a photovoltaic solar cell module assembly  1 F comprising three photovoltaic solar cell modules  2 F, the backflow preventing diode  55  is inserted into the cable  5  immediately before the positive electrode side of the cable is bifurcated, as shown in  FIG. 10B , to prevent backflow of a DC current generated in the modules  2 F.  
         [0079]     In a photovoltaic solar cell module assembly  1 G (with the structure substantially equal to that of the module assembly  1 A of the first embodiment) comprising four photovoltaic solar cell modules  2 G, the backflow preventing diode  55  is inserted into a middle portion of the module assembly (or between the middle modules), as shown in  FIG. 10C , to prevent backflow of a DC current generated in the modules  2 G.  
         [0080]     Thus, the backflow preventing diode  55  is arranged anywhere inside the wiring circuit of the photovoltaic solar cell module and the position of arrangement is arbitrary.  
         [0081]     By inserting the backflow preventing diode  55  into the wiring circuit, the output is made further stable in the photovoltaic solar cell module assembly comprising a number of modules, the wiring system and the photovoltaic power system.  
         [0082]     The power element built in the photovoltaic solar cell module, in the above-described embodiments has various types such as crystalline silicon base, amorphous silicon base, compound base and the like. The present invention can be applied to any type of the power element.  
         [0083]     The crystalline silicon-based photovoltaic solar cell is a photovoltaic solar cell containing crystalline silicon as the semiconductor material. The photovoltaic solar cell can be further classified into single crystal, polycrystal and microcrystal.  
         [0084]     The amorphous silicon-based photovoltaic solar cell contains amorphous silicon as the semiconductor material.  
         [0085]     The compound-based photovoltaic solar cell contains garium arsenide (GaAs), CuInSe 2  called CIS base, and the like, as the semiconductor material.  
         [0086]     According to the present invention, the photovoltaic solar cell module assembly which generates the operating voltage corresponding to the power conditioner operating voltage is prepared by connecting a plurality of photovoltaic solar cell modules in series, and the photovoltaic power system is formed by connecting the photovoltaic solar cell module assemblies in parallel. Thus, it is unnecessary to install the photovoltaic solar cell modules while counting the number of modules in series connection at the installation place and errors in wiring are not generated due to errors in counting.  
         [0087]     In addition, according to the present invention, the photovoltaic solar cell module assemblies have only to be connected in parallel at the installation place. Therefore, the number of installation steps at the installation place is reduced, dangerous rooftop wiring operations are simplified, and the installation costs are remarkably reduced.  
         [0088]     Furthermore, according to the present invention, the photovoltaic solar cell modules do not need to be connected in parallel. Therefore, design in wiring connection of the photovoltaic solar cell modules can be simplified and the installation operability at the installation place can also be improved.