JP2004193586A - Solar power generator, its manufacturing method and solar power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar power generator in which a configuration is simplified and a manufacturing cost is reduced while the effect of a partial shadow and the dispersion of characteristics can be decreased. <P>SOLUTION: The solar power generator has one solar cell 1 formed on a substrate and a plurality of power converters 2 being connected to the solar cell 1 and converting an output from the solar cell. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a photovoltaic power generation device, a photovoltaic power generation system, and a method for manufacturing a photovoltaic power generation device.

  In recent years, problems such as global warming due to emission of carbon dioxide and the like accompanying the use of fossil fuels, accidents at nuclear power plants, and radioactive contamination by radioactive waste have become serious, and interest in the global environment and energy has been increasing. Under these circumstances, photovoltaic power generation using sunlight, geothermal power generation using geothermal energy, wind power generation using wind power, and the like have been put to practical use worldwide as an inexhaustible and clean energy source.

  Among these, as a form of solar power generation using a solar cell, there are various forms corresponding to the output scale from several W to several thousand kW. As a typical system using solar cells, DC power generated by the solar cells is converted into AC power by an inverter or the like (orthogonal conversion) and converted into a consumer load or a commercial power system (hereinafter simply referred to as a “system”). There is a photovoltaic power generation system that supplies

  FIG. 2 is a diagram showing a schematic configuration of a conventional general photovoltaic power generation system. As illustrated, the solar power generation system 8 includes a solar cell module 6 in which a plurality of solar cells are connected in series, and a solar cell string 7 (in which a plurality of the solar cell modules 6 are connected in series). A solar cell array is also formed by connecting a plurality of the solar cell strings 7 in parallel, and a DC output from the solar cell array is collected in a current collection box 9 to collect power. Is generally converted into AC power by an inverter 3 and connected to a load 4 or a commercial system 5.

  In such a photovoltaic power generation system 8, when the output between the plurality of photovoltaic strings 7 is different due to the variation in the output characteristics of the photovoltaic cells and the influence of partial shadows caused by buildings, etc., There is a case where it is not possible to perform the operation in.

  In order to cope with such a problem, for example, in Patent Document 1, a DC-DC converter is provided via a connection box for each solar cell array, and each DC output power is collectively input to an inverter to obtain AC power. A solar power generation system that performs conversion into electric power is disclosed. According to this configuration, the accuracy of the optimal power point tracking control of the photovoltaic power generation system is improved by performing the optimal power point tracking control on the solar cell array connected to each DC-DC converter.

  Further, in Patent Document 2, by providing an inverter for each solar cell array, solar cell module or solar cell, differences in power efficiency due to output variations and partial shadows among the solar cell array, solar cell module or solar cell. It is disclosed that by reducing the power consumption and installing an inverter for each solar cell module or solar cell, it is possible to cope with an increase or decrease in the amount of power generated by the solar cell at low cost.

  However, in a solar power generation system described in Patent Document 1 in which a DC output of a solar cell array or a solar cell module is input to a DC-DC converter (DC / DC converter), a plurality of solar cells are provided. Need to be connected in series to create a solar cell module.

  In general, in order to create a solar cell module, for example, a cutting step for dividing a stack of electromotive force layers on a substrate into units of solar cells, a non-power generation area for insulation between the solar cells, An end etching step for providing, a step of sequentially connecting solar cells in series using a wiring member such as an interconnector, a step of connecting a bypass diode for reducing the influence of partial shadows, a series of solar cells A very large number of steps are required, such as the step of covering the group and the step of fitting the frame to the end of the covered one, so it takes time and the cost of each member used is high. Is a factor that raises prices.

  In particular, when manufacturing a large-area solar cell module, the process of connecting a large number of solar cells in series takes time and effort, which is a major problem when manufacturing a large-area solar cell module. Become.

  In addition, when a plurality of solar cells are connected in series by using a wiring member such as an interconnector, a gap for inserting the interconnector between the solar cells is required. Since the number increases with the number of connections, a non-power generation area that is not used for power generation increases in the solar cell module. As a result, the area power generation efficiency of the solar cell module decreases.

  In addition, since the solar cells are connected in series, the influence of the partial shadow on the power generation efficiency also increases. For example, if one of the solar cells connected in series is covered with a partial shadow, the generated current of that cell decreases, and the generated current of the other cells is also limited by this cell.

  In order to reduce the influence of the partial shadow, it is necessary to connect a bypass diode in parallel to each of the solar cells connected in series. However, even if this method is used, the influence of the partial shadow on other power-generating cells cannot be completely eliminated.

  Further, as described in Patent Document 2, if an inverter is provided for each solar cell, the work of the series connection step, which is the above problem, may be reduced, but each solar cell is created. In this case, a cutting step and an etching step for the end of each solar cell are required, which still requires time and labor.

  When each solar cell is installed on a support, the solar cells must be accurately installed at regular intervals to improve electrical insulation, aesthetics, and area power generation efficiency of each solar cell. However, this operation is difficult and causes an increase in cost.

  Japanese Patent Application Laid-Open No. H11-163,199 discloses that individual components formed on a single substrate can solve the above-described problems of complicated steps in series connection, increase in cost, influence of partial shadows, and difficulty in installation work. A solar cell module in which all the solar cells are connected in parallel to form a module is disclosed.

  In this solar cell module, a current collecting bus bar is connected to the current collecting electrode of each solar cell, and the output of a plurality of cells is collected and output as one.

  However, in such a configuration, the current flowing through the current-collecting bus bar has a value obtained by adding the output currents of a plurality of cells, and accordingly, as the number of solar cells increases and the solar cell module increases in area, Another problem arises in that the loss during current collection is very large.

  In order to solve the problem of the current collection loss, it is conceivable to increase the cross-sectional area of the current collection bus bar. However, this solution significantly increases the weight and volume of the current collection bus bar, and the Carrying work becomes difficult.

JP-A-2000-112545 JP-A-8-70533 U.S. Pat. No. 4,773,944

  The present invention has been made in view of the above situation, and has a simple configuration, reduces manufacturing costs, and can reduce the influence of partial shadows and variations in characteristics. Provided are a photovoltaic power generation system used and a method for manufacturing a photovoltaic power generation device.

  The configuration of the present invention is as follows.

That is, the first invention is a solar power generation device,
It is characterized by comprising one solar cell formed on a substrate, and a plurality of power converters individually connected to the solar cell and converting the output of the solar cell.

In the first aspect of the present invention, it is preferable that the plurality of power converters are DC-DC converters that boost a DC voltage output from a solar cell.
Further, it is preferable that the plurality of power conversion devices are inverters.
Further, it is preferable to have a live part exposed at least in a part of a wiring member for electrically connecting the solar cell and the power converter.
Further, the solar cell has a photoelectric conversion layer, a current collecting electrode disposed on the light receiving surface side of the photoelectric conversion layer, a surface wiring member, and a transparent thin resin layer, and the solar cell includes the current collecting electrode or the surface wiring member. It is preferable that at least a portion has an exposed portion that is not covered with the transparent thin film resin layer.
Further, it is preferable that the photoelectric conversion layer is made of thin-film silicon.
Further, it is preferable that the substrate is conductive and the photoelectric conversion layer has a configuration in which the substrate side is a positive electrode.
Preferably, the substrate is conductive, and one of an output from the solar cell and one of an output of the DC-DC converter is electrically connected to the substrate.
Further, it is preferable that one of the outputs from the solar battery cells and one of the outputs of the DC-DC converter are both on the low voltage side.
Further, it is preferable that one of the outputs from the solar cells and one of the outputs of the DC-DC converter are both on the high voltage side.
Further, it is preferable that the solar battery cell has a portion on which no power generation unit is formed on two peripheral sides.
Further, it is preferable that the solar cell is fixed to a support via a portion where the power generation unit is not formed.
Further, it is preferable that the solar battery cell or the solar power generation device itself is sealed with a resin.
Further, it is preferable that the solar cell is a minimum power generation unit having a function as a solar cell.
In addition, the power supply device further includes a plurality of current collecting electrodes for individually collecting the power of the solar battery cells, and the plurality of current collecting electrodes is individually converted into the power collected by the plurality of current collecting electrodes. It is preferable that the power converters are connected to the plurality of power converters as described above.

A second invention is a solar power generation system,
One or more solar cells including one solar cell formed on a substrate, and a plurality of DC-DC converters individually connected to the solar cells and converting a DC output of the solar cells. A photovoltaic device,
An inverter that converts outputs of the plurality of DC-DC converters into AC power and supplies the AC power to a load or system-linked to a commercial power system.

  In the second aspect of the present invention, it is preferable that the inverter has an insulating transformer and a wiring member connecting the DC-DC converter and the inverter is grounded.

A third invention is a solar power generation system,
One or a plurality of photovoltaic power generation units each including: one solar cell formed on a substrate; and a plurality of inverters individually connected to the photovoltaic cells and converting output of the photovoltaic cells into AC power. Equipment,
The plurality of inverters supply output power to a load or are interconnected to a commercial power system.

A fourth invention is a method for manufacturing a photovoltaic power generator,
The method includes a step of forming a solar cell on a substrate by a semiconductor manufacturing step, and a step of connecting a plurality of power conversion devices to a predetermined portion of the solar cell.

  In the fourth aspect of the present invention, a photovoltaic cell is formed by continuously forming a photoelectric conversion layer, a current collecting electrode, and a surface wiring member on the substrate, and the photovoltaic cell is continuously formed on a predetermined portion of the photovoltaic cell. It is preferable to connect a power converter.

  ADVANTAGE OF THE INVENTION According to this invention, a solar power generation device can be comprised using only one solar cell formed on the board | substrate. Therefore, for example, one long and large-area solar battery cell can be used, and a solar power generation device using this can be configured. For this reason, when the solar cell module is of a type that requires a cutting step, an end etching step, a series connection step, a bypass diode connection step, and the like at the time of its manufacture, the cutting step, the end etching step, and the series connection step In addition, a bypass diode connection step and the like become unnecessary. The production and material costs are accordingly reduced. In addition, since the non-power generation area that is not used for power generation is reduced, the area power generation efficiency of the photovoltaic power generator is significantly improved.

  Also, there is no need to install a plurality of solar cells on the support at equal intervals. Instead, the solar cells can be installed in units of solar power generation devices having solar cells having a larger area. The time required for installation of the power generator can be greatly reduced, and the cost for installation can be reduced.

  In addition, the effect due to the partial shadow is limited to only the power conversion devices related to the shadowed portion, and does not affect other power conversion devices. In addition, since a solar power generation device is configured with only one solar cell on a substrate, a semiconductor layer, an electrode layer, and the like on a single conductive substrate can be obtained by continuous film formation. For this reason, the variation in the electrical characteristics of the solar cell in the solar power generation device is small. Therefore, compared with a conventional system having a plurality of solar cells connected in series, the influence of partial shadows and variations in characteristics can be significantly reduced.

  Furthermore, since the current collection loss can be significantly reduced, the cross-sectional area of the members that connect the DC-DC converters in parallel can be considerably reduced, and the material costs can be significantly reduced, and the weight can be reduced. Ease is improved.

  Hereinafter, preferred embodiments of a solar power generation device and a solar power generation system according to the present invention will be described in detail with reference to the drawings.

<First embodiment>
FIG. 1 is a schematic diagram showing the configuration of the first embodiment of the photovoltaic power generation system according to the present invention. Reference numeral 1 denotes one solar cell formed on a conductive substrate, 2 denotes a DC-DC converter, 3 denotes an inverter, 4 denotes a load, and 5 denotes a commercial system.

  In this specification, a solar cell refers to a minimum unit having a function as a solar cell from which electric power can be extracted. For example, when the power generation region is separated by an etching line, a solar cell that has a photovoltaic layer separated by an etching line or the like in a certain region and can extract power therefrom The minimum unit having the function of The solar cell is not limited to a single photoelectric conversion layer, and may be a stack of a plurality of photoelectric conversion layers. For example, as a stack of a plurality of photoelectric conversion layers, a tandem structure or the like is given, and a stack of a plurality of photoelectric conversion layers having different spectral sensitivities is a minimum power generation unit as a solar cell capable of extracting power. Become.

  Here, the DC power output from the solar cells is input to DC-DC converters 2 provided at predetermined intervals on the solar cells, respectively, and after being boosted at a predetermined step-up ratio, these outputs are output. Are collectively input to the inverter 3, converted into AC power of the commercial frequency, supplied to the load 4, and the surplus power is transmitted to the commercial system 5.

  In the following, a device including the solar cell 1 and a plurality of DC-DC converters 2 connected to the solar cell is referred to as a solar power generator 106.

  Hereinafter, components used in the photovoltaic power generation device and the photovoltaic power generation system of the present embodiment will be described in detail.

[Solar cell]
FIG. 3 is a cross-sectional view illustrating a layer configuration of the solar cell 1 formed on the conductive substrate, and illustrates a configuration in which the lower electrode layer 11, the semiconductor layer 12, and the upper electrode layer 13 are stacked on the conductive substrate 10. Have. Note that, depending on the configuration of the conductive substrate 10, the lower electrode layer 11 may be omitted.

  Here, it is preferable that the conductive substrate 10 is wound in advance in a roll shape, and the above-described layers are stacked while sequentially sending out the substrate, and a continuous film forming method such as a roll-to-roll method in which the other end is wound up. It is preferable to create it in consideration of productivity, and the description here mainly describes a case using this method. In addition, a batch type apparatus can of course be used.

  The lower electrode layer 11, the semiconductor layer 12, and the upper electrode layer 13 used here are described in detail in the specification of Japanese Patent Application Laid-Open No. 11-186572 by the same applicant as the present application. In the present invention, these components are not an essential part, and a detailed description is omitted.

  As the semiconductor layer 12, thin-film silicon is preferable, and amorphous silicon is particularly preferable. When amorphous silicon is used as the semiconductor layer, a pin formed by stacking an n-type semiconductor, an i-type semiconductor, and a p-type semiconductor in this order from the conductive substrate 10 side Bonding is usually used.

  It is also preferable to use a double or triple configuration in which two or three layers of the above-described pin junction or pn junction are stacked.

  Further, in the present embodiment, a nip junction in which a p-type semiconductor, an i-type semiconductor, and an n-type semiconductor are stacked in this order from the conductive substrate 10 side is suitably used depending on the case.

  The method for forming each layer can be appropriately selected from various publicly known methods such as an evaporation method, a sputtering method, a high-frequency plasma CVD method, a microplasma CVD method, an ECR method, a thermal CVD method, and an LPCVD method.

Next, in order to cut the solar cell stack formed as described above into a desired length and to divide the solar cell stack, the effect of a short circuit between the conductive substrate and the upper electrode layer, which occurs at the time of division and cutting, is effectively received. An etching paste containing FeCl ₃ , AlCl ₃ , or the like is applied on the upper electrode layer by a screen printing method so as not to affect the range, and after heating and washing, a part of the upper electrode layer of the solar cell stack is lined. Then, an etching line 115 as shown in FIG. 4 is formed.

  Then, as also shown in FIG. 4, the insulating double-sided adhesive tape 25 is continuously attached to one side of the light receiving surface of the conductive substrate, and the current collecting electrodes 14 are formed at predetermined intervals on the insulating double-sided adhesive tape 25 and the upper electrode. . Further, the light-receiving surface terminal member 16 is attached to the upper portion of the insulating double-sided adhesive tape 25 by heat compression. The collecting electrode 14 used here will be described in detail later.

  Through the above steps, the solar cell assembly 401 provided with the current collecting electrode 14 and the light receiving surface terminal member 16 as shown in FIG. 4 is manufactured.

  Then, as shown in FIG. 5, the transparent thin-film resin layer 23 is laminated on the light receiving surface of the solar cell assembly 401 to form a solar cell assembly 501. Note that, here, regardless of the presence or absence of the transparent thin film resin layer 23, it is referred to as a solar cell assembly in this specification. In addition, as described later, the solar cell is referred to regardless of the presence or absence of the transparent thin film resin layer. The configuration and method of forming the transparent thin film resin layer will be described later in detail.

  When the transparent thin-film resin layer 23 is formed, the solar cell unit assembly 501 may be formed by forming the transparent thin-film resin layer 23 only on a part of the light-receiving surface, not on the entire surface. According to such a configuration, unnecessary insulating material is not required, so that the cost can be reduced for the photovoltaic power generator and the entire system.

  Specifically, for example, the transparent thin-film resin layer 23 is not provided on the entire surface of the solar cell assembly 401, but only on a minimum necessary portion so as not to affect the power generation performance in an outdoor environment. That is, the transparent thin-film resin layer 23 is not formed on the light-receiving surface side terminal member 16 or the etching line 115, and at least a portion (active area) having photoelectric conversion characteristics with respect to incident light of the solar cell may be covered. .

  Then, the solar cell assembly 501 on which the transparent thin-film resin layer 23 is laminated is cut along the etching line 115 at a desired length to form the solar cell 1. Further, a plurality of DC-DC converters 2, which will be described in detail later, are provided at predetermined intervals in the solar battery cell 1 and further electrically connected to each other so that the solar cell as shown in FIG. The photovoltaic device 106 can be configured. In this case, the disconnection may be performed after the DC-DC converter 2 is connected.

  With such a configuration of the photovoltaic power generation device, the area of the active area increases because there is no etching line for dividing the photoelectric conversion layer between the DC-DC conversion devices, and the area conversion efficiency of the solar cell is improved. It has the effect of doing. That is, this solar cell includes one minimum unit having a function as a solar cell capable of extracting power from the photovoltaic layer.

  In addition, the solar cell 1 may be sealed with a weatherproof film, a filler, a back surface reinforcing material, etc. in the same manner as in a conventional solar cell module or the like in the following step to protect the solar cell 1 from the outdoor environment. Structures can also be used in the present invention.

  Next, each component of the solar cell 1 of the present embodiment will be described in detail.

[Conductive substrate]
The conductive substrate 10 used in the solar cell according to the present embodiment is a member that mechanically supports a semiconductor layer for photoelectric conversion, and can be used as an electrode on the non-light receiving surface side of the solar cell. The substrate preferably has heat resistance enough to withstand a heating temperature when a semiconductor layer is formed.

  In addition, since the conductive substrate serves as an adherend when the solar cell is adhered to a support such as a concrete block, a material having good adhesiveness to an adhesive used is preferable.

  When the conductive substrate is fixed on a support using a fixing member, the conductive substrate preferably has mechanical strength, weather resistance, and corrosion resistance enough to withstand the fixing.

  Examples of the material of the conductive substrate include metals such as Fe, Ni, Cr, Al, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb, and alloys thereof, such as thin plates such as brass and stainless steel. The composite, a carbon sheet, and a galvanized steel sheet are mentioned.

  Further, a material using an electrically insulating material as a substrate may be used, such as a film of a heat-resistant synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, epoxy, or the like. Sheets or composites of these with glass fibers, carbon fibers, boron fibers, metal fibers, and the like, and those obtained by depositing or laminating a metal thin film of a different material on the surface of a thin plate or a resin sheet thereof are also used.

[Current collecting electrode]
The collecting electrode 14 is generally formed in a comb shape on the semiconductor layer or the upper electrode layer of the solar cell, and a suitable width and pitch are determined from the sheet resistance values of the semiconductor layer and the upper electrode layer.

Further, the collector electrode is required to have a low specific resistance so as not to be a series resistance of the solar cell, and a preferable specific resistance is 10 ⁻² Ωcm to 10 ⁻⁶ Ωcm. As a material of the current collecting electrode, for example, a metal such as Ti, Cr, Mo, W, Al, Ag, Ni, Cu, Sn, Pt, an alloy thereof, a solder, or a metal having a surface coated with a conductive adhesive is used. A line or the like is used. Generally, a metal paste in which a metal powder and a polymer resin binder are in the form of a paste is used, but the present invention is not limited to this.

[Terminal member]
The terminal member 16 is a member that is electrically connected to the current collecting electrode 14 to form a plus or minus extraction electrode. The terminal member 16 is formed on the etched surface of the conductive substrate or the solar cell from which the upper electrode layer is removed by laser welding, a conductive adhesive, brazing, or the like so as to have an electrical low resistance, and mechanically. Can be firmly mounted. Alternatively, it is mounted on the collecting electrode by a press. In the present specification, the terminals are distinguished from “light-receiving surface terminal members” and “non-light-receiving surface terminal members” according to the positions of the solar cells to which the terminal members are attached.

  The electrical performance and material required for the terminal member are almost the same as those of the above-mentioned current collecting electrode, but the shape is preferably a foil shape which can maintain the flatness of the solar cell and reduce the resistance.

  In addition, the non-light receiving surface terminal member can be spread over the entire non-light receiving surface in a comb shape or a radial shape to improve current collection efficiency.

  When a terminal member for connection with a DC-DC converter or an inverter is required, the terminal member may be attached to the light-receiving surface terminal member or the non-light-receiving surface terminal member by a method such as laser welding, conductive adhesive, or brazing. Attach and extend.

[Transparent thin film resin layer]
The transparent thin-film resin layer 23 located on the light-receiving surface of the solar cell in the present embodiment is not particularly limited as long as it is transparent and can cover and protect the lower current collecting electrode, the upper electrode layer, and the like. Absent. However, preferably, those having excellent coatability, excellent weather resistance and adhesion are preferable, and those having particularly excellent waterproofness are required.

  Specific materials include a fluorine-based resin, an acrylic resin, polyester, and polycarbonate. More specifically, there are polyvinylidene fluoride (PVdF) resin, polyvinyl fluoride (PVF) resin, ethylene tetrafluoride-ethylene copolymer (ETFE) resin, and the like. Polyvinylidene fluoride resin is excellent from the viewpoint of weather resistance, but ethylene tetrafluoride-ethylene copolymer resin is excellent in terms of compatibility between weather resistance and mechanical strength and transparency. Further, in order to reduce costs, it is preferable to use an acrylic or fluorine-based transparent paint instead of a film material. In this case, the coating is performed by a coating method such as a curtain coat which is usually used for coating.

  From the requirements in the manufacturing process, it is preferable to use a resin paint that can use the curtain flow method with a low viscosity of about 0.3 Pa · s or less. Further, from the viewpoint of increasing productivity, a spray coating method is preferable, and in this case, a resin coating having a low viscosity of 0.05 Pa · s or less is preferable.

  The lower limit of the viscosity is not particularly limited and can be appropriately selected from a desired film thickness. However, the lower the viscosity is, the more the number of coatings required to form a required film thickness becomes lower. Therefore, it is practically preferable to be about 0.001 Pa · s or more.

  The thickness of the transparent thin film resin layer 23 is preferably 1 μm or more as a thickness that can be applied without pinholes, and more preferably about 200 μm or less from the following viewpoints.

  In view of protecting the current-collecting electrode, upper electrode layer or photovoltaic layer with a transparent thin-film resin layer, it is preferable to use a thicker layer. Decreases. Further, the flexibility of the resin layer may be impaired by forming a thick layer. In addition, if it is thicker, the current collecting electrode, the upper electrode layer or the photovoltaic layer may be destroyed due to shrinkage during curing, and when used outdoors, when the resin layer is thicker, when it becomes about 200 μm or more, The resin layer may not be able to follow the thermal expansion or the force at the time of installation, and the resin layer may be stressed and cracked, or may be peeled off at the interface with the current collecting electrode, the upper electrode layer, or the photovoltaic layer.

  However, the transparent thin-film resin layer does not necessarily need to be formed of one type of material, and for example, can be formed of two types of layers using two types of materials. In this case, a material having good adhesion to the upper electrode layer may be selected immediately above the upper electrode layer of the solar cell, and a material having excellent weather resistance may be selected thereon. As a typical forming method in this case, it is conceivable to perform the application step twice.

[Parallel connection members]
In order to configure the photovoltaic power generator of the present embodiment, parallel connection between the DC-DC converters 2 connected to the respective solar cells is required. A member for making these connections is a parallel connection member. In the case where the conductive substrate is used as a common terminal on one side in the solar cell of the present embodiment, this member is used for only one pole on one side.

  Specifically, this member is a member for connecting one output terminal of each DC-DC converter 2, and a general-purpose insulated wire, an insulated cable, or the like may be used, but is used in the present embodiment. As an example, a bare conductor without an insulating coating is used. As the bare conductor, a copper wire, a copper stranded wire, a copper band, or the like is preferable.

[Connecting members between devices]
In the present embodiment, a connection member between the DC-DC converter 2 and the inverter 3 is defined as an inter-device connection member. The same shape and the same material as the parallel connection member can also be used for the inter-device connection member. Further, it is also possible to extend the parallel connection member used for connection between the DC-DC converters and connect the DC-DC converters to the inverter, instead of the inter-device connection member.

[Support]
The support refers to a member for fixing the solar cell, and is generally a gantry or a member forming an installation surface.

  The means for fixing the solar cell to the support is not limited, but a method of fixing the solar cell using an adhesive is preferable because the area of the non-power generation region in the solar cell can be small. Further, a non-power generation area for installation may be provided in a part of the solar cell, and the part may be fixed by a fixing member such as a nail, a screw, or a bolt.

  In the present embodiment, since the structure is simple and the installation work is simple, it is preferable to use a concrete material suitably. This is because if the support is a heavy material such as concrete, the placement of the support (stand) is completed only by placing the support on the ground. Also, concrete has high outdoor durability and is inexpensive, so it is convenient to use it as a mount for solar cells.

  Further, it is preferable that the support is divided into, for example, a plate-like fixed support (support) for fixing the solar cell and a back support on which the fixed support is installed. This is convenient, for example, by installing a back support such as a cubic shape and then arranging a fixed support such as a plate on the back support so that the installation angle of the solar cell can be changed arbitrarily. Is better.

  Next, the DC-DC converter and the inverter according to the present embodiment will be described in detail.

[DC-DC converter]
Generally, a DC-DC converter connected to a solar cell includes a booster circuit that boosts a DC voltage to an input voltage of an inverter circuit, and starts / stops power conversion, optimizes an operating point of a solar cell, an operation mode, and the like. Control circuit, system interconnection protection circuit, communication circuit, input / output terminals, etc., whose output may be directly connected to the load, but in general, multiple outputs are input to one inverter. Then, the converted AC power is used at the load or connected to the grid.

  As the booster circuit, various known and used circuit configurations can be used regardless of insulation or non-insulation. The control circuit includes, for example, a CPU, a PWM waveform control circuit, an optimum power point tracking control circuit, a control power generation circuit, a frequency / voltage reference generator, a switching control circuit, and the like. In addition, the control circuit may be operated externally via a communication line or the like, and a part of the function of the control circuit may be arranged outside the DC-DC converter to control a plurality of power converters collectively. You can also.

  However, the DC-DC converter 2 according to the present embodiment has a control power generation circuit and a switching reference waveform generation circuit that defines a switching frequency as control circuits in order to simplify the structure as much as possible and to reduce costs and improve reliability. A configuration having at least a circuit and a switching element driving circuit capable of driving the switching element with a fixed duty is preferable.

  Further, it is preferable that the main circuit includes a switching element that is turned on / off by the switching element drive circuit, and a switching transformer that is formed with a predetermined turns ratio.

  In a system in which a plurality of DC-DC converters that drive switching elements at the fixed duty are connected in parallel, the input voltage of the DC-DC converter can be changed by changing the input voltage of the inverter at the subsequent stage. Thereby, the operating point of the solar cell can be moved.

  In addition, a series of operations for connecting the DC-DC converter to the solar cell by forming the DC-DC converter into a chip and electrically connecting the surface wiring member and the conductive substrate during the manufacturing process of the solar cell. Can also be simplified.

  Further, the DC-DC converter is desirably installed near the solar cell so as to reduce wiring loss in order to efficiently input the output from the solar cell, and may be directly attached to the solar cell. desirable.

  In addition, the exterior material of the DC-DC converter has properties such as heat resistance, moisture resistance, water resistance, electrical insulation, cold resistance, oil resistance, weather resistance, impact resistance, and waterproofness, depending on the usage conditions. Must have. In order to firmly fix to the solar cell or the back surface reinforcing material, a material having good adhesiveness with an adhesive is preferably used.

  Taking the above factors into consideration, as the exterior material, for plastics, for example, polycarbonate, polyamide, polyacetal, modified PPO (PPE), polyester, polyarylate, unsaturated polyester, phenolic resin, epoxy resin, polybutylene terephthalate, nylon, etc. Resin, engineering plastics, etc. In addition, thermoplastic resins such as ABS resin, polypropylene, and polyvinyl chloride can also be used.

  When the DC-DC converter is mounted on the light-receiving surface side, it is preferable to use carbon black as a pigment or apply a resin paint that absorbs ultraviolet light to the surface in order to improve the resistance to ultraviolet light.

[Inverter]
Generally, in the case of an inverter used in a photovoltaic power generation system, a booster circuit that boosts an input DC voltage to an input voltage of an inverter circuit, an inverter circuit that converts DC power into AC power, and start / stop of power conversion It consists of a control circuit for optimizing the operating point of the solar cell, controlling the operation mode, etc., a grid connection protection circuit, a communication circuit, input / output terminals, etc., and its output is used for the load or connected to the grid. You.

  As the booster circuit, various publicly known and used circuit systems, whether insulated or non-insulated, can be used. As the inverter circuit, a voltage type inverter using an IGBT or a MOSFET as a switching element is preferable. By driving the gate of the switching element by a control signal of the control circuit, AC power having a desired frequency, phase, and voltage can be obtained.

  The control circuit includes, for example, a CPU, a PWM waveform control circuit, a frequency / voltage reference generator, an optimum power point tracking control circuit, a current reference generator, a mode switch, a switching control circuit, and the like. When a plurality of inverters according to the present embodiment are connected to one solar cell, the control circuit may be externally operable via a communication line or the like, and the control circuit itself is centrally arranged outside the inverter. Thus, a plurality of inverters can be collectively controlled.

  Further, when the inverter according to the present embodiment is electrically connected to the solar cell, it is preferable that the inverter is installed near the solar cell in order to efficiently input the output from the solar cell. It is desirable to connect directly.

  Inverters 3 include a type having an insulation transformer and a type not having an isolation transformer. Either type may be used depending on the application. However, when the connection member between the DC-DC converter and the inverter is grounded, Uses an inverter having an insulating transformer.

  The inverter needs to have performances such as heat resistance, moisture resistance, water resistance, electric insulation, cold resistance, oil resistance, weather resistance, impact resistance, and water resistance according to the use conditions. In addition, a material having good adhesiveness with an adhesive is preferably used for firmly fixing the solar cell.

  Taking the above factors into consideration, as the exterior material, for plastics, for example, polycarbonate, polyamide, polyacetal, modified PPO (PPE), polyester, polyarylate, unsaturated polyester, phenolic resin, epoxy resin, polybutylene terephthalate, nylon, etc. Resin, engineering plastics, etc. In addition, thermoplastic resins such as ABS resin, polypropylene, and polyvinyl chloride can also be used.

  When the inverter is mounted on the light receiving surface side, it is preferable to use carbon black as a pigment or apply a resin paint that absorbs ultraviolet light to the surface in order to improve the resistance to ultraviolet light.

  Next, a method for manufacturing the photovoltaic power generation device and the photovoltaic power generation system of the present embodiment will be described in detail.

[Production method]
FIG. 6 is a schematic external view of the photovoltaic power generation system of the present embodiment, in which 602 is a photovoltaic cell having the configuration described above, 2 is a DC-DC converter, 3 is an inverter, 4 is a load, and 5 is a commercial system. It is.

Specifically, first, a rolled long stainless steel substrate having a length of 300 m having a thickness of 0.1 mm and a width of 250 mm was transported as the conductive substrate 10, and the lower electrode layer 11 contained 1% of Si. Al was formed to a thickness of 5000 ° by a sputtering method. Next, the p / i / n-type amorphous silicon semiconductor layer 12, an n-type as the semiconductor PH _3, SiH _4, the H ₂ gas, the i-type SiH ₄ as a semiconductor, the H ₂ gas, also As the P-type semiconductor, B ₂ H ₆ , SiH ₄ , and H ₂ gases are used, respectively, and the n-type semiconductor layer is 300 °, the i-type semiconductor layer is 4000 °, the p-type semiconductor layer is 100 °, and the stainless steel substrate is each formed by a plasma CVD method. Were sequentially formed for each of the film forming apparatuses through which.

  Thereafter, as the upper electrode layer 13, an ITO film having a thickness of 800 ° was formed by resistance heating evaporation.

Next, in order to divide the photovoltaic layer thus formed into a plurality of parts, an etching paste containing FeCl ₃ , AlCl _3, or the like is applied on the upper electrode of a portion to be divided by a screen printing method, and washed after heating. By doing so, a part of the upper electrode was linearly removed to form an etching line 115 with a width of 1 mm at intervals of 5500 mm, and a photovoltaic layer separated by the etching line was formed.

  Then, as shown in FIG. 4, first, a polyimide base double-sided adhesive tape 25 (thickness 200 μm (base 100 μm)) as an insulating double-sided adhesive tape having a width of 7.5 mm is continuously attached to one side of the light receiving surface side of the conductive substrate. To go.

  Thereafter, a carbon wire in which carbon paste was previously coated on a copper wire having a diameter of 100 μm was formed at a pitch of 5.6 mm on the power generation region of the photovoltaic layer and on the polyimide base material double-sided adhesive tape 25 to form the current collecting electrode 14.

Then, a silver-plated copper foil having a width of 5 mm, a length of 245 mm, and a thickness of 100 μm is placed as a light receiving surface terminal member 16 on the upper surface of the polyimide base material double-sided adhesive tape 25, and then 200 ° C., about 4 × 10 ⁵ Pa (3 kgf) / Cm ² ) for 180 seconds at the same time as the current collecting electrode 14.

  Further, as shown in FIG. 5, a transparent thin-film resin layer 23 was laminated on the light-receiving surface of the solar cell by coating a 100 μm-thick fluororesin paint by a spray coating method. The transparent thin film resin layer was laminated so as to cover only a portion (active area) having photoelectric conversion characteristics with respect to incident light of the solar cell.

  And it cuts out from a roll at an interval of 5500 mm along the said etching line, and the solar cell 602 (FIG. 6) formed on a conductive substrate and having a transparent thin-film resin layer is obtained.

  Further, extension members (not shown) are connected to the light-receiving surface terminal member 16 and the conductive substrate 10 as connection terminals to the DC-DC converter 2, and ten DC-DC converters 2 are connected to the light-receiving surface every 500 mm. After bonding a part of the side terminal member 16 with a silicone adhesive so as to cover it, and connecting the extending member and the input terminal of the DC-DC converter 2 inside the DC-DC converter 2, the DC-DC conversion is performed. By covering the device 2, a solar power generation device 601 to which the DC-DC converter 2 is attached as shown in FIG. 6 is created. Note that, in the present embodiment, the conductive substrate 10 also serves as an electrode for extracting power from the solar cell.

  Further, the photovoltaic power generator 601 is attached to the support 56 with an epoxy resin adhesive.

  Then, the ten DC-DC converters 2 attached to the solar cells 602 are sequentially connected by the connection cable 24 and input to the inverter 3 collectively.

  The connection cable 24 includes two wires of positive and negative electrodes, and each cable is electrically connected to an output terminal of the DC-DC converter inside the DC-DC converter, It is electrically connected to a cable connected to an adjacent DC-DC converter.

  The photovoltaic power generators 601 are sequentially installed on the ten supports 56 in the same manner, and their outputs are similarly converted to AC power via the inverter 3 and supplied to the load 4 or the system 5.

[Description of operation]
Here, with reference to the circuit diagrams of the DC-DC converter 2 shown in FIG. 7 and the inverter 3 shown in FIG. 8, each main circuit, control circuit and each operation will be described in detail.

  In the DC-DC converter 2 shown in FIG. 7, the output power of the solar cell is accumulated in the capacitor 28 through the input terminal 27 of the DC-DC converter 2, and the AC is obtained by turning ON / OFF the MOSFETs 29 and 30 alternately. Converted to electric power.

  Then, the AC power input to the switching transformer 31 is converted into AC power according to a predetermined transformation ratio (in this embodiment, 1: 175), further rectified by the diode bridge 32, passed through the filter capacitor 33, -Output from the DC converter 2 to the inverter 3.

  Although not used in the present embodiment, a filter coil may be provided between the diode bridge 32 and the filter capacitor 33, and depending on the system configuration, both the filter capacitor and the filter coil may be omitted. .

  Next, the control circuit 34 of the DC-DC converter 2 will be described. The control circuit 34 of the present embodiment includes a control power generation circuit 35, a reference waveform generation circuit 36, and a MOSFET driver 37. The input of the control power generation circuit 35 is connected to both ends of the capacitor 28, and the MOSFET driver 37 The control signal output is connected to the gates of MOSFETs 29 and 30.

  The detailed operation of the control circuit 34 will be described below. When the voltage of the photovoltaic cell 1 reaches the starting voltage of the control power generation circuit 35, the output voltage of the control power generation circuit 35 is input to the reference waveform generation circuit 36 and the MOSFET driver 37.

  First, the reference waveform generation circuit 36 operates, a rectangular wave having a preset reference frequency is input to the waveform input section of the MOSFET driver 37, and the gate drive signals S1 and S2 are supplied from the MOSFET driver 37 to the gates of the MOSFETs 29 and 30. And turns on / off the MOSFETs 29 and 30 alternately at a fixed duty.

  Further, as shown in FIG. 8, the main circuit of the inverter 3 includes an input terminal 38 to which the output power of the plurality of DC-DC converters 2 is input, a smoothing capacitor 39, and transistors 40a, 40b, 40c, and 40d. And a full bridge circuit 41, a coil 42, and a capacitor 43.

  Further, the control circuit of the inverter 3 is divided into a part for controlling start / stop of power conversion, optimization of an operating point of the solar cell, an operation mode, and the like. Here, the control circuit relates to PWM control related to the present invention. A detailed description will be given only of the portion with reference to FIG.

  As shown, the PWM control unit includes an input voltage detection circuit 45, a band-pass filter (BPF) 46, an output current detector 47 (shown in FIG. 8), a DC voltage constant control circuit 48, a DC voltage reference voltage source 49, It comprises a multiplier 50, an output current control error amplifier 51, a PWM modulation circuit 52, and a gate drive circuit 53 for driving the transistors 40a to 40d of the full bridge circuit 41.

Further, as a specific method of the PWM control, first, the inverter input voltage _VDC is detected by the input voltage detection circuit 45, and the inverter input voltage _VDC and the reference voltage of the DC voltage reference voltage source 49 are detected by the DC voltage constant control circuit 48. An error signal S7 from _Vref is generated, and this error signal S7 is used as one input of the multiplier 50. Further, to detect the commercial system voltage V _CS, extracts the fundamental wave component to the reference sine wave signal S8 as the other input of the multiplier 50 by the BPF 46. The multiplier 50 multiplies the input error signal S7 by the reference sine wave signal S8 to generate an inverter output current reference signal S9.

Further, the error amplifier 51 inputs the inverter output current reference signal S9 from the multiplier 50 and the inverter output current I _OUT detected by the output current detector 47, and modulates the modulation reference error signal S10 obtained by amplifying the difference between the two by PWM modulation. Output to the circuit 52. The PWM modulation circuit 52 performs PWM control based on the input modulation reference signal S10, drives the transistors 40a to 40d by the gate drive signals S3 to S6 via the gate drive circuit 53, and outputs an inverter input corresponding to the reference voltage _Vref. Control is performed so that voltage _VDC is obtained.

  Note that the operation of the full bridge circuit is well known, and a description thereof will be omitted.

  As described above, when the outputs of the plurality of DC-DC converters 2 that perform control such that the MOSFETs are switched at a fixed duty to make the boost ratio constant are connected to the inverter 3 that performs constant input voltage control, -The input voltage of the DC converter 2 operates at a constant level. This is because the DC-DC converter that performs constant step-up ratio control at a fixed duty acts as an impedance converter, and as a result, control is performed so that the operating voltage of the solar cell becomes constant. .

  That is, in the present embodiment, when the input voltage of the inverter 3 is set to 175 V, the output voltages of all the DC-DC converters 2 connected to the input side of the inverter 3 become approximately 175 V, and The operating voltage of the photovoltaic cell will operate at an optimum operating voltage of about 1V.

  Although the case where the inverter 3 performs the constant input voltage control has been described above, the power is measured from the voltage and the current of the inverter input unit by using a current detection circuit (not shown) in the input unit of the inverter. The input voltage of the inverter may be controlled so as to perform maximum power tracking control that maximizes the magnitude of power.

  In this case, the input voltage of the DC-DC converter 2 can be changed by changing the input voltage of the inverter 3, that is, the output voltage of the solar cell can be changed. In this case, the output voltage of the solar battery cell that maximizes the input power to the inverter 3 can be set only by the maximum power tracking control of the inverter 3.

  As described above, in the present embodiment, by forming a long and large-area solar cell on a conductive substrate, a cutting step and an edge etching step necessary for manufacturing a conventional general solar cell module are performed. This eliminates the need for a series connection step and a bypass diode connection step, thereby reducing manufacturing and material costs and greatly improving the area power generation efficiency of the photovoltaic power generator.

  Furthermore, instead of installing the solar cells one by one at equal intervals, a photovoltaic power generation device having a long and large-area solar cell formed on one conductive substrate may be installed on a support. Installation work is easy because it is good. Therefore, as compared with the conventional installation work in which solar cells are installed one by one and connected to each other, the time required for installation of the solar power generation device can be significantly reduced, and the cost for installation can be reduced.

Further, since a plurality of DC-DC converters are respectively connected in parallel to a long and large-area solar cell formed on one conductive substrate, a plurality of solar cells are connected in parallel by a wiring member. Compared with the conventional configuration in which the output is connected to the inverter at a time, when the voltage step-up ratio of the DC-DC converter is set to about n times, when the wiring having the same sectional area (the same resistance value) is used. In this case, the current collection loss can be reduced to about (1 / n) ² . Therefore, the cross-sectional area of the members that connect the DC-DC converters in parallel can be considerably reduced, so that the cost of the members can be significantly reduced, the weight can be reduced, and the ease of installation can be improved.

  In addition, since there is no solar cell connected in series, the influence of the partial shadow is limited to only the DC-DC converter near the portion where the partial shadow has occurred, and to other DC-DC converters. Has no effect. Therefore, it is possible to construct a photovoltaic power generation system which is far less affected by partial shadows than a conventional system having solar cells connected in series. Compared with a conventional system having the same power generation capacity, this effect becomes significant in proportion to the magnitude of the power generation capacity.

  Further, as described above, in the conventional system having solar cells connected in series, when output characteristics of individual solar cells vary, the effect of a solar cell having poor output characteristics affects other solar cells. In addition, the output of the entire photovoltaic power generation system is reduced. However, according to the photovoltaic power generation system of the present embodiment, since it is composed of only one solar cell on the conductive substrate, the semiconductor layer, the electrode layer, etc. on one conductive substrate are continuously formed. Therefore, the variation in the characteristics of the solar cell due to the manufacturing is small, and the variation in the output characteristics is very small.

  As described above, according to the photovoltaic power generation system according to the present embodiment, a special effect, which cannot be achieved conventionally, that a shadow loss or a loss due to characteristic variation can be reduced is obtained.

  Further, the DC-DC converter connected to the solar cell is controlled so as to have a fixed boost ratio and a constant boost ratio, and an inverter in which a plurality of such DC-DC converters are connected in parallel is used to control the input voltage constant or By performing the maximum power tracking control, the operating point of each solar cell can be controlled by one inverter, thereby simplifying the control unit of each DC-DC converter, improving the reliability and reducing the power consumption. Costs.

  Furthermore, in a conventional photovoltaic power generation system having solar cells connected in series, if such a structure is used in which the live parts are exposed, for example, simplification of environmental resistance coating of the solar cells and / or solar cells In this embodiment, the members connected in series and parallel between the cells are exposed without using an insulating coating, but in this case, the following problem occurs.

  That is, since at least a part of the active part of the electrode or the wiring member of the solar cell and the serial / parallel connection member between the solar cells is exposed and non-insulated, the active part is wet by rainwater or the like (the solar cell active part). And the resistance between the ground and the ground is reduced by moisture), and when there is a solar radiation state thereafter, [solar cell active part]-[rainwater]-[wet support material]-[rainwater]-[earth], Alternatively, a leak current path is formed by a path of [solar cell active part]-[rainwater]-[earth].

  As a result, there arises a problem that metal ions constituting the live part flow out of the live part, and the corrosion of the electrode, the wiring member or the series-parallel connection member is promoted. In particular, it has been found that when copper is used for the series-parallel connection member, the copper is ionized and remarkably eluted by the formation of the current path, and the life of the connection member is greatly reduced.

  In other words, in the above conventional solar power generation system, when a plurality of solar cells are connected in series, the potential difference from the ground at the most positive end of the series connection body becomes very large, and the corrosion of the connection member tends to proceed. Would. In order to cope with this, it is conceivable to connect the solar cells in parallel, but in this case, the number of cells connected in parallel increases and the current flowing increases. Since the current collection loss is proportional to the square of the current, there is a problem that if the current collection loss is suppressed to a certain value or less, the cross-sectional area of the parallel connection member becomes considerably large.

  In the present embodiment, a plurality of DC-DC converters are connected to one solar cell even when the solar power generation system has a structure in which a live part is exposed to promote cost reduction. As a result, the potential of the solar battery cell with respect to the ground is extremely small as compared with the conventional system in which the series connection is performed, so that the promotion of corrosion of the wiring member can be prevented and the reliability is improved.

<Second embodiment>
Hereinafter, a second embodiment of the photovoltaic power generation system according to the present invention will be described. In the following, description of the same parts as those in the first embodiment will be omitted, and the description will focus on the characteristic parts of the present embodiment.

  FIG. 10 is an external view showing a schematic configuration of the second embodiment, and FIG. 11 is an equivalent circuit diagram of the second embodiment.

  As the solar battery cells 1 of the present embodiment, those that are substantially the same as those of the first embodiment are used, and a detailed description thereof will be omitted.

  FIG. 12 is an enlarged view of a connection portion between the solar cell 1 of this embodiment and the DC-DC converter 2. Here, the position where the DC-DC converter 2 is attached in the solar battery cell is the same as that of the first embodiment, except that the output terminal 59 extends from the exterior part of the DC-DC converter 2. Is different.

  The output terminal 59 is a terminal member connected to the high-voltage output terminal of the DC-DC converter 2, and prevents moisture or the like from entering the DC-DC converter 2 from the outlet of the output terminal 59. Meanwhile, the inside of the DC-DC converter 2 is filled with a filler.

  As the internal main circuit of the DC-DC converter 2 of the present embodiment, the same circuit as that of the first embodiment described with reference to FIG. 7 is used, but in the present embodiment, the circuit diagram of FIG. As shown in (1), the primary-side low-voltage side terminal and the secondary-side low-voltage side terminal of the switching transformer 31 are electrically connected to the conductive substrate 10 of the solar cell 1, respectively, so that The low voltage side of the voltage side and the secondary side are set to the same potential.

Then, as shown in FIG. 14, a copper band 62 having a cross-sectional area of 0.1 mm ² is previously laid on the support 56 in advance as a parallel connection member with an epoxy-based adhesive. The photovoltaic cells to which the DC converter 2 is attached are adhered and fixed on the support 56, and the output terminals 59 extended from the DC-DC converter 2 are sequentially electrically connected to the copper strip 62.

  Further, the low-voltage side inter-device wiring member 63 is connected to the conductive substrate 10, the inter-device wiring member 63 and the copper band 62 are input to the inverter 3, and the DC power output from each DC-DC converter 2 is input. Is converted to AC power, and is connected to a load or a commercial system.

  In this embodiment, a high frequency transformer type inverter 64 of the type shown in FIG. In the inverter 64, the DC output from the DC-DC converter 2 is converted into a high-frequency AC by a high-frequency inverter 65, which is insulated by a small high-frequency transformer 66. , And further converted by a DC / AC converter 68 into an alternating current having a commercial frequency and output.

  Further, in the present embodiment, as shown in FIG. 10, the copper strip 62 is grounded to complete the photovoltaic power generation system. That is, in the configuration of the present embodiment, since each of the plurality of DC-DC converters 2 is electrically one beforehand via the conductive substrate 10 of the solar cell 1, the output terminal of the DC-DC converter is One is in a state of being wired by a conductive substrate, and has an excellent feature that only one wire is required to connect the DC-DC converters.

  Further, in the present embodiment, in order to reduce the cost, a method of coating only the active area with a transparent thin resin layer without using a sealing material is adopted.

  By grounding the copper band 62 as the parallel connection member as described above, as shown in the equivalent circuit diagram of the photovoltaic power generation system in FIG. 11, the copper band 62 on the high voltage side of the parallel connection member is grounded. On the other hand, the potential becomes zero.

  Therefore, the low voltage side of the parallel connection member has a negative potential with respect to the ground, the conductive substrate 10 connected thereto has the same potential, and the low voltage side of the solar cell 1 also has a negative potential.

  At this time, the voltage at both ends of the solar cell 1 is smaller than the potential difference between the copper band 62 and the conductive substrate 10, and the high voltage side members such as the light receiving surface terminal member of the solar cell 1 are also grounded. Therefore, the promotion of corrosion of the wiring member can be prevented.

  In the present embodiment, copper (Cu) is used as the parallel connection member 62 and the inter-device wiring member 63. However, as a physical property of copper, as shown in a potential-pH diagram shown in FIG. Has been found to be easily eluted. In the present embodiment, in view of this characteristic, the wiring member made of copper is always kept at zero or a negative potential with respect to the ground to prevent the elution of copper.

  As described above, according to the photovoltaic power generation system of the present embodiment, in addition to the effects obtained by the first embodiment, the potential of the solar cell and the wiring member with respect to the ground becomes zero or a negative potential. Corrosion is less likely to occur, and the effect of improving reliability is obtained.

<Third embodiment>
Hereinafter, a third embodiment of the photovoltaic power generation system according to the present invention will be described. In the following, description of the same parts as in the first and second embodiments will be omitted, and the description will focus on the characteristic parts of the present embodiment.

  The solar cell used in the present embodiment has substantially the same configuration as the solar cell used in the first embodiment, but differs only in the stacked configuration of the semiconductor layers.

Specifically, Al containing 1% of Si was formed as a lower electrode layer on a washed long stainless steel substrate of 0.1 mm as a conductive substrate by sputtering to a film thickness of 5000 °. Next, the n / i / p type amorphous silicon semiconductor layer, a P-type as the semiconductor _{B 2 H 6, SiH 4,} H 2 gas, as the i-type semiconductor to gas SiH _4, H _2, As the n-type semiconductor, PH ₃ , SiH ₄ , and H ₂ gases were used, respectively, and a p-type semiconductor layer was formed at 100 °, an i-type semiconductor layer was formed at 4000 °, and an n-type semiconductor layer was formed at 300 ° by plasma CVD. .

  Then, an n / i / p type amorphous silicon semiconductor layer was stacked again to form a double-structured layer.

  Thereafter, as the upper electrode layer, an ITO film having a thickness of 800 Å was formed by resistance heating evaporation to form a solar cell.

  Then, from here on, a single solar cell was completed on the conductive substrate by using the same steps as in the first embodiment. Then, a plurality of DC-DC converters are connected to this solar cell at equal intervals.

  In this embodiment, since the n / i / p type amorphous silicon semiconductor layer is used for the solar cell, the conductive substrate side is the high voltage side of the solar cell unlike the first embodiment. As shown in FIG. 19, the main circuit of the DC-DC converter includes a primary-side high-voltage side and a secondary-side high-voltage side of the switching transformer 31 inside the DC-DC converter 2 as shown in FIG. By electrically connecting to the conductive substrate 1801, the primary high voltage side and the secondary high voltage side are set to the same potential.

  Then, as in the second embodiment, the photovoltaic power generation device is installed on the support 56, and the connection with the inverter 3 is made. In this embodiment, the conductive substrate 10 is grounded, as shown in FIG. The solar power generation system according to the present embodiment is obtained.

  Note that, as the inverter 3, a high-frequency insulation type inverter is used as in the second embodiment.

  In the present embodiment, a bare copper band is used as the low voltage side member 62 of the parallel connection member, but a member with an insulating coating can also be suitably used.

  Further, in this embodiment, in order to reduce the cost, a method is adopted in which only the active area where no sealing material is used is coated with a transparent thin resin layer. The circuit configuration of the entire photovoltaic power generation system is shown in FIG. Can be expressed as

  As shown in the equivalent circuit diagram of the photovoltaic power generation system in FIG. 18, by grounding the conductive substrate 10, which is a common electrode of each photovoltaic cell 1801, the photovoltaic cell 1801 and the inter-device wiring member The high voltage side of 63 is at zero potential with respect to ground.

  Therefore, all the other wiring members are kept at a negative potential with respect to the ground, so that the promotion of corrosion of the wiring members can be prevented.

  As described above, according to the photovoltaic power generation system of the present embodiment, in addition to the effects obtained by the first embodiment, the potential of the solar cell and the wiring member with respect to the ground becomes zero or a negative potential. Corrosion hardly occurs, and the effect of improving reliability is obtained.

<Fourth embodiment>
Hereinafter, a fourth embodiment according to the present invention will be described. In the following, description of the same parts as those in the first to third embodiments will be omitted, and the description will focus on the characteristic parts of the present embodiment.

  FIG. 20 is a diagram illustrating a part of the solar cell used in the solar power generation device according to the present embodiment. As illustrated, the solar cell 1 used in the present embodiment has the same configuration as the solar cells of the first to third embodiments, except that semiconductor layers are provided at both ends of the conductive substrate. Has no installation part 130.

  The specific manufacturing method is the same as that of the first embodiment, using a rolled long stainless steel substrate of 0.1 mm as a conductive substrate, and forming the lower electrode layer, the semiconductor layer, and the upper electrode layer with a conductive material. The substrates were laminated with a width of 20 mm from both ends of the substrate, and a portion where these layers were not provided was set as a mounting portion 130.

  Then, as shown in FIG. 20, the space between the upper electrode layer and the installation part 130 was linearly removed, and an etching line 131 was formed to separate the installation part 130 and the live part.

  Further, similarly to the first embodiment, the DC-DC converter 2 is attached to form a photovoltaic power generation device, which is set on a support.

  In the present embodiment, fixing to the support is performed by hitting nails for concrete at intervals of 30 cm on the installation portion 130 with a tacking machine.

  Although a concrete member is used as the support, it may be formed of wood, plastic, or the like. In that case, the support may be fixed using nails, screws, or the like.

  As described above, according to the present embodiment, the photovoltaic power generator can be installed more easily, and the cost for installation can be reduced.

<Fifth embodiment>
Hereinafter, a fifth embodiment according to the present invention will be described. In the following, description of the same parts as those in the above-described embodiment will be omitted, and the description will focus on the characteristic parts of this embodiment.

  FIG. 21 is a diagram illustrating a schematic configuration of the present embodiment. As illustrated, a photovoltaic power generation device 2001 according to the present embodiment has a configuration in which a plurality of DC-DC converters 2004 are connected to a solar cell 2002. Has become.

  As the solar cell 2002 used in the present embodiment, the same solar cell as in the second embodiment before performing the transparent thin-film resin layer coating step is used, and the light-receiving surface terminal member 2005 and the conductive substrate are used. Are electrically connected to a plurality of DC-DC converters 2004.

  Further, an output terminal (not shown) of each DC-DC converter 2004 is electrically connected to a terminal member 2005, whereby all the DC-DC converters 2004 are connected in parallel.

  In the present embodiment, the entire solar cell assembly is resin-sealed in a state where the DC-DC converter is connected by the weather-resistant film, the filler, and the back surface material. FIG. 22 is a cross-sectional view taken along line XX ′ of FIG. 21, where 2006 is a weather-resistant film, 2007 is a filler, 2008 is a back surface material, 2009 is a light-receiving surface terminal member, and 2010 is a double-sided adhesive tape. .

  Specific examples of materials used for the sealing include ETFE (ethylene tetrafluoroethylene) for the weather-resistant film 2006, EVA (ethylene-vinyl acetate copolymer, weather-resistant grade) for the filler 2007, and a backing material. For 2008, a Tedra / Aluminum / Tedra sheet is suitable.

  As a method of sealing, a laminate in which a back material, a filler, a solar cell assembly, a filler, and a weather-resistant film are laminated in this order is formed by melting the filler at 150 ° C. using a vacuum laminator.

  At this time, a terminal member 2005 extending from the solar cell assembly is exposed from an end of the sealing material, and an electrical connection to an adjacent solar power generation device, an inverter, or the like can be performed using the terminal member 2005. It is possible.

  According to the photovoltaic power generator of the present embodiment as described above, the same effects as in the second embodiment can be obtained.

<Other embodiments>
Although the photovoltaic power generation system according to the embodiment of the present invention described above supplies power to a commercial power grid, the photovoltaic power generation system of the present invention is not limited to a commercial AC power grid such as a private AC power generation facility in a factory or the like. Of course, power may be supplied to the AC power system.

1 is a schematic diagram illustrating a configuration of a solar power generation system according to a first embodiment of the present invention. It is a figure showing the schematic structure of the conventional general photovoltaic power generation system. It is sectional drawing which shows the example of a structure of the solar cell of FIG. FIG. 2 is a diagram illustrating a schematic configuration of the solar cell of FIG. 1. FIG. 2 is a diagram for explaining a manufacturing process of the solar cell of FIG. 1. It is an outline view showing an outline of a photovoltaic power generation system of a first embodiment of the present invention. FIG. 2 is a circuit diagram illustrating an example of a DC-DC converter. It is a circuit diagram showing an example of an inverter. FIG. 4 is a diagram illustrating a PWM control method of the inverter according to the present invention. It is an outline view showing the outline of the photovoltaic power generation system of a 2nd embodiment of the present invention. FIG. 11 is a circuit diagram illustrating a schematic configuration of the solar power generation system in FIG. 10. It is the elements on larger scale which show each solar cell of FIG. FIG. 11 is a circuit diagram showing a connection between a main circuit of the DC-DC converter of FIG. 10 and a conductive substrate of a solar cell. It is a figure which shows the method of installing the solar power generation system of FIG. It is a figure which shows the schematic structure of the high frequency insulation type inverter used in the solar power generation system of FIG. It is a figure which shows the potential-pH diagram of copper. It is an outline view showing the outline of the photovoltaic power generation system of a 3rd embodiment of the present invention. FIG. 18 is a circuit diagram illustrating a schematic configuration of the solar power generation system in FIG. 17. FIG. 18 is a circuit diagram showing a connection between a main circuit of the DC-DC converter of FIG. 17 and a conductive substrate of a solar cell. It is an outline view showing the outline of the photovoltaic power generator concerning a 4th embodiment of the present invention. It is an outline view showing the outline of the solar power generation device concerning a 5th embodiment of the present invention. It is sectional drawing in X-X 'of FIG.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1, 602, 1801, 2002 Solar cell 2, 2004 DC-DC converter 3 Inverter 4 Load 5 Commercial system 6 Solar cell module 7 Solar cell array 8 Solar power generation system 9 Collector box 10 Conductive substrate 11 Lower electrode layer DESCRIPTION OF SYMBOLS 12 Semiconductor layer 13 Upper electrode layer 14 Current collecting electrode 16 Light receiving surface terminal member 23 Transparent thin film resin layer 24 Connection cable 25 Insulated double-sided adhesive tape 27 Input terminal 28 Capacitor 29, 30 MOSFET
31 Switching Transformer 32 Diode Bridge 33 Filter Capacitor 34 Control Circuit of DC-DC Converter 35 Control Power Generation Circuit 36 Reference Waveform Generation Circuit 37 MOSFET Driver 38 Input Terminal 39 Smoothing Capacitor 40a-d Transistor 41 Full Bridge Circuit 42 Filter Coil 43 Filter Capacitor 45 Input voltage detection circuit 46 Bandpass filter (BPF)
47 Output Current Detector 48 DC Voltage Constant Control Circuit 49 DC Voltage Reference Voltage Source 50 Multiplier 51 Output Current Control Error Amplifier 52 PWM Modulator 53 Gate Drive Circuit 56 Support 59 Output Terminal 62 Copper Strip 63 Device Wiring Member 64 High frequency insulation type inverter 65 High frequency inverter 66 High frequency transformer 67 AC / DC converter 68 DC / AC converter 106, 601, 2001 Photovoltaic power generator 115, 131 Etching line 130 Installation part 401, 501 Solar cell assembly 2005 Terminal member 2006 Weatherproof Functional film 2007 Filler 2008 Back material 2009 Light receiving surface terminal member 2010 Double-sided adhesive tape

Claims (20)

  A solar power generation device comprising: one solar cell formed on a substrate; and a plurality of power converters individually connected to the solar cell and converting an output of the solar cell.   The photovoltaic power generator according to claim 1, wherein the plurality of power converters are DC-DC converters that boost a DC voltage output from a solar cell.   The solar power generation device according to claim 1, wherein the plurality of power conversion devices are inverters.   4. The photovoltaic power generation device according to claim 1, further comprising a live part exposed on at least a part of a wiring member that electrically connects the photovoltaic cell and the power conversion device. 5. .   The solar cell has a photoelectric conversion layer, a current collecting electrode disposed on a light receiving surface side of the photoelectric conversion layer, a surface wiring member, and a transparent thin film resin layer, and at least one of the current collecting electrode or the surface wiring member. The solar power generation device according to any one of claims 1 to 4, wherein the portion has an exposed portion that is not covered with the transparent thin film resin layer.   The photovoltaic power generation device according to claim 5, wherein the photoelectric conversion layer is made of thin-film silicon.   The solar power generation device according to claim 5, wherein the substrate is conductive, and the photoelectric conversion layer has a configuration in which the substrate side has a positive electrode.   The said board | substrate is electroconductive, One of the output from the said solar cell and one of the output of the said DC-DC converter are electrically connected to the said board | substrate, The Claims characterized by the above-mentioned. Solar power plant.   The solar power generation device according to claim 8, wherein one of an output from the solar cell and one of an output from the DC-DC converter is on a low voltage side.   The solar power generation device according to claim 8, wherein one of an output from the solar cell and one of an output from the DC-DC converter is on a high voltage side.   The photovoltaic power generation device according to any one of claims 1 to 10, wherein the photovoltaic cell has a portion where no power generation unit is formed on two surrounding sides.   The photovoltaic power generation device according to claim 11, wherein the photovoltaic cell is fixed to a support via a portion where the power generation unit is not formed.   The photovoltaic power generation device according to any one of claims 1 to 12, wherein the photovoltaic cell or the photovoltaic power generation device itself is sealed with a resin.   The solar power generation device according to any one of claims 1 to 13, wherein the solar cell is a minimum power generation unit having a function as a solar cell.   It further has a plurality of current collecting electrodes for individually collecting the power of the solar battery cells, and the plurality of current collecting electrodes is such that the power individually collected by the plurality of current collecting electrodes is individually converted. The photovoltaic power generator according to claim 14, wherein the photovoltaic power generator is connected to each of the plurality of power converters. One or more solar cells including one solar cell formed on a substrate, and a plurality of DC-DC converters individually connected to the solar cells and converting a DC output of the solar cells. A photovoltaic device,
A solar power generation system comprising: an inverter that converts outputs of the plurality of DC-DC converters into AC power and supplies the AC power to a load or system-links to a commercial power system.   17. The photovoltaic power generation system according to claim 16, wherein the inverter has an insulating transformer, and a wiring member connecting the DC-DC converter and the inverter is grounded. One or a plurality of photovoltaic power generation units each including: one solar cell formed on a substrate; and a plurality of inverters individually connected to the photovoltaic cells and converting output of the photovoltaic cells into AC power. Equipment,
A solar power generation system, wherein the plurality of inverters supply output power to a load or are connected to a commercial power system.   A method for manufacturing a photovoltaic power generator, comprising: a step of forming a solar cell on a substrate by a semiconductor manufacturing step; and a step of connecting a plurality of power converters to a predetermined portion of the solar cell.   A photovoltaic cell is formed by continuously forming a photoelectric conversion layer, a collecting electrode, and a surface wiring member on the substrate, and the power conversion device is continuously connected to a predetermined portion of the photovoltaic cell. The method for manufacturing a photovoltaic power generator according to claim 19.

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