JP6301912B2 - Natural energy power generation system - Google Patents

Description

  Embodiments described below generally relate to a natural energy power generation system.

  A wind power generation system having a windmill and a photovoltaic power generation system having a power generation module such as a solar cell are attracting attention as a clean energy system. Various conventional photovoltaic power generation systems such as silicon solar cells (single crystal silicon, polycrystalline silicon), compound solar cells, silicide solar cells, and dye sensitized solar cells have been put into practical use. These solar cells generate light by receiving light such as sunlight.

  The output voltage of the solar cell varies greatly with time. This is due to fluctuations in the amount of sunlight. The change in the amount of sunlight causes a large change even if the weather is slightly cloudy. In order to prevent this output fluctuation, for example, as shown in Japanese Patent Application Laid-Open No. 2012-253848 (Patent Document 1), a power conditioner is used to suppress fluctuations in the output voltage. By using the power conditioner, the output voltage can be stabilized. However, in this method, the power conditioner must always be operated, and there is a problem that the load of the power conditioner is large. In particular, there is a problem that the load increases as the output voltage increases.

JP 2012-253848 A

  The problem to be solved by the present invention is to provide a natural energy power generation system capable of stabilizing an output voltage in a power generation module.

The natural energy power generation system according to the embodiment includes a power generation module that includes at least one power generation unit that converts natural energy into electric power, and an electric storage that includes at least one power storage device that stores part of the electric power converted by the power generation unit. In the natural energy power generation system having a power storage function including a module, the power generation module and the power storage module are connected in parallel, and by adding the output power from the power storage module to the output power from the power generation module, Ri stabilization can der output power as an energy generating system, to the average value a (W) of the output of the power generation module in 60 minutes, it varies the minimum output 0.7A or less, or the maximum output is higher 1.3A The output power can be stabilized as a renewable energy power generation system even when The output of the natural energy power generation system is in the range of A ± 0.25 A (W), the power storage device includes tungsten oxide powder as the porous electrode layer, and the porous electrode layer has a film thickness of It is 1 μm or more, the porosity is 20 to 80% by volume, and the internal resistance is 20 Ω · cm ² or less .

It is a mimetic diagram for illustrating the composition of the natural energy power generation system concerning an embodiment. It is a mimetic diagram for illustrating the composition of the electrical storage module of an embodiment. It is a figure which shows the output voltage of the electric power generation system which concerns on the comparative example 1. FIG. It is a figure which shows the output voltage of the electric power generation system which concerns on Example 4. FIG.

  Hereinafter, embodiments of the present invention will be illustrated with reference to the accompanying drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

  FIG. 1 is a schematic diagram for illustrating the configuration of the photovoltaic system according to the present embodiment. In FIG. 1, reference numeral 1 denotes a natural energy power generation system (photovoltaic power generation system), 2 is a power generation module, 3 is a power storage module, 4 is a diode, 5 is a power conditioner, and 6 is a load.

  First, the photovoltaic system according to the embodiment is a photovoltaic system having a power storage function including the power generation module 2 and the power storage module 3.

  The power generation module 2 has at least one power generation unit that converts natural energy into electric power. Natural energy includes sunlight or wind power. That is, the power generation unit converts natural energy into electric power using the photovoltaic effect or the wind photovoltaic effect. Sunlight is likely to change the amount of sunlight, and wind power is likely to change.

  As a power generation part, it can comprise with a solar cell (it is also called a photocell etc.) etc., for example. When the power generation unit is a solar cell, the type of solar cell is not particularly limited. When the power generation unit is a solar cell, a solar cell panel formed on one transparent substrate (such as a glass plate) is counted as one power generation unit. For example, the power generation unit can be composed of a silicon-based solar cell, a compound-based solar cell, an organic solar cell, or the like.

  Examples of the silicon-based solar battery include those using crystalline silicon or amorphous silicon.

  As crystalline silicon, those using single crystal silicon (single crystal silicon type), those using polycrystalline silicon (polycrystalline silicon type), those using fine crystalline silicon (microcrystalline silicon) Type) and the like.

  In addition, a structure in which crystalline silicon and amorphous silicon are stacked (hybrid type) or a plurality of silicon layers having different absorption wavelength ranges (multi-junction type) can be used.

  Examples of compound solar cells include those using InGaAs (indium gallium arsenic), GaAs (gallium arsenic), I-III-VI group compounds called chalcopyrites, and the like.

  Examples of organic solar cells include solar cells that obtain photovoltaic power using organic dyes (dye-sensitized solar cells), solar cells that obtain photovoltaic power using organic thin film semiconductors (organic thin film solar cells), and the like. Can be illustrated.

  The power generation unit is not limited to the illustrated example, and any power generation unit can be used as long as it can convert light energy such as sunlight into electric power by utilizing the photovoltaic effect. Further, the power generation unit may be configured by wind power generation, that is, a device capable of converting wind power into electric power. The power generation module 2 may connect a plurality of power generation modules in series. Further, when combining a plurality of power generation modules, a photovoltaic power generation module and a wind power generation module may be combined.

  Next, the power storage module 3 will be described. The power generation module includes at least one power storage device that stores a part of the power converted by the power generation unit. As the power storage device, a capacitor-type power storage module described later is preferable. Further, the power storage module 3 may connect a plurality of power storage modules in series.

  The power generation module 2 and the power storage module 3 are connected in parallel. In addition, when a plurality of power generation modules are connected in series, the plurality of power generation modules connected in series are connected in parallel to the power storage module as one power generation module. When a plurality of power storage modules are connected in series, the plurality of power storage modules connected in series are connected to the power generation module in parallel as a plurality of power storage modules. Further, the power generation module and the power storage module may be connected in parallel with a plurality of power generation modules connected in series as one power generation module and a plurality of power storage modules connected in series as one power storage module.

  In the natural energy power generation system according to the embodiment, the power generation module 2 and the power storage module 3 are connected in parallel, and the output power from the power storage module is added to the output power from the power generation module, whereby the output as the natural energy power generation system is achieved. The power can be stabilized.

  The power storage module can store a part of the output voltage of the power generation module. In addition, the power storage module can add a part of the stored electricity to the output voltage of the power generation module. By storing electricity in the power storage module and adding a part thereof to the output voltage, the output voltage of the natural energy power generation system can be stabilized.

  By storing a part of the output power of the power generation module, especially the part where the output voltage is high, and supplying the part of the electricity stored in the part where the output voltage is low, the output voltage of the natural energy power generation system greatly fluctuates up and down It is possible to stabilize the output voltage. For this reason, even if the output voltage of a power generation module such as a solar cell fluctuates up and down due to slight fluctuations in the amount of sunshine, the fluctuation range in the vertical direction can be reduced and a stable output voltage can be obtained. Further, regarding wind power generation, even if the output voltage of the power generation module fluctuates up and down due to fluctuations in the air volume, the fluctuation range in the vertical direction can be reduced, and a stable output voltage can be obtained.

  Moreover, it is preferable to provide a diode 4 between the power generation module 2 and the power storage module 3. Further, by providing the diode 4 between the power generation module 2 and the power storage module 3, it is possible to prevent a backflow phenomenon in which a current from the power storage module 3 flows into the power generation module 2. By providing the diode 4 for preventing the backflow, the power of the power storage module 2 can be efficiently applied.

  Moreover, in FIG. 1, the structure which stuck the electrical storage module on the back surface of the electric power generation module is shown. When the natural energy power generation system is to be made compact, a structure in which a power storage module is installed on the back surface of the power generation module is preferable. In addition, the natural energy power generation system of embodiment is not limited to such a structure, The power generation module and the electrical storage module should just be connected in parallel.

  The natural energy power generation system 1 is connected to a power conditioner 5. A load 6 is connected to the power conditioner 5. The load 6 is not particularly limited as long as the load 6 is a facility that uses electric power, such as a small power facility such as a personal computer or a television, a medium or large scale facility such as a home or factory, or a comprehensive facility such as a smart grid.

  The power conditioner is a system that converts electric power supplied from the natural energy power generation system so that it can be used by the load 6. Electric power supplied from a natural energy power generation system such as a solar cell is direct current. On the other hand, the electricity used in the load 6 is generally alternating current. The power conditioner is a device that converts direct current supplied from the natural energy power generation system into alternating current that can be used by the load 6. The conventional natural energy power generation system is a DC voltage whose output voltage greatly increases and decreases due to slight fluctuations in the amount of sunlight and the air volume. In order to convert the AC voltage to a stable AC voltage by the power conditioner, the power conditioner must be complicated and large. For this reason, an increase in the size and price of the power conditioner has been invited.

  On the other hand, since the natural energy power generation system according to the present embodiment has a unit structure in which the power generation module and the power storage module are connected in parallel, the output voltage of the natural energy power generation system can be stabilized. it can. Therefore, it is possible to reduce work loads such as conversion work from direct current to alternating current by the power conditioner and conversion to the target output voltage. For this reason, when the same output is calculated | required, size reduction of a power conditioner can be achieved. In addition, since the burden of conversion from direct current to alternating current can be reduced, the output can be increased (the watt hour Wh can be increased). Therefore, an easy-to-use natural energy power generation system can be provided.

  In the natural energy power generation system of the embodiment, by stabilizing the output, when the average value of the output of the power generation module is A (unit: W (watt)), the output of the natural energy power generation system is A ±. It can suppress within the range of 0.25A (W). This means that it is possible to suppress variations in output within a range of ± 25% with respect to the average output A (W).

  In a general silicon-based solar cell, the variation in output due to the variation in the amount of sunlight generates a large variation exceeding ± 30% with respect to the average output A (W). In the natural energy power generation system of the embodiment, output variations can be suppressed within a range of ± 25%. In other words, even when the minimum output is 0.7 A or less or the maximum output is 1.3 A or more with respect to the average value A (W) of the output of the power generation module, it is possible to stabilize the output power as a natural energy power generation system. It shows that it is.

  Further, the reduction ratio is preferably 40% or more. The reduction rate is obtained by reduction rate (%) = [(maximum output fluctuation width of natural energy power generation−maximum output fluctuation width of combined output) / maximum output fluctuation width of natural energy power generation] × 100. The combined output is an output of the natural energy power generation system of the embodiment. The closer the reduction rate is to 100%, the more smoothing (stabilization of output) is performed.

  Moreover, when the average value of the output of the power generation module is A (W), the power storage capacity (J) of the power storage device is preferably 300 (seconds) × A (W) or more. When the plurality of power storage modules are connected in series, the total value of the power storage capacity of the power storage device is the power storage capacity of the power storage module. Further, when the power storage capacity (J) of the power storage device is 300 (seconds) × A (W) or more, the output of the natural energy power generation system can be in the range of A ± 0.25 A (W). Further, by setting the storage capacity (J) to 350 (seconds) × A (W) or more, the output of the natural energy power generation system can be in the range of A ± 0.20 A (W). Also, the reduction rate can be 50% or more.

  Next, the power storage module 3 will be described. The structure of the power storage module is not particularly limited as long as it has the power storage capacity described above, but preferable power storage modules include the following.

  The power storage device of the power storage module preferably includes tungsten oxide powder as the porous electrode layer. The tungsten oxide powder is preferably a tungsten trioxide powder having a hexagonal crystal structure.

  As described above, the power storage module is required to perform power storage and discharge almost simultaneously. For this purpose, there is a demand for a power storage device that can easily store and discharge electricity, and can increase the speed of charging and discharging (so-called instantaneous power). By including a tungsten oxide powder as the porous electrode layer, it is possible to efficiently store and discharge.

The tungsten oxide powder is preferably a tungsten trioxide powder having a hexagonal crystal structure. Tungsten trioxide only _needs to approximate the stoichiometric ratio to WO ₃ and can be regarded as tungsten trioxide functionally if it is in the range of WO _2.6 to _3.0 .

  Tungsten oxide has various crystal structures such as monoclinic, triclinic and hexagonal. In the power storage module of the embodiment, it is preferable that a part (part or all) having a hexagonal crystal structure is present in one grain of tungsten oxide powder.

By providing the tungsten oxide powder, particularly tungsten trioxide (WO ₃ ) powder, with a hexagonal crystal structure, it is possible to efficiently deliver Li ions and improve the electrode reaction. The hexagonal crystal structure tungsten trioxide has a tunnel structure that becomes a diffusion channel of Li ions composed of a six-membered ring of WO ₆ octahedron inside the crystal structure, so that the diffusion of Li in the crystal is fast. Thus, the internal resistance during the charge / discharge reaction can be reduced. In addition, by speeding up the diffusion of Li, various batteries (storage battery, dye-sensitized solar cell, capacitor, Li ion secondary battery) using the tungsten oxide (WO ₃ ) powder according to the embodiment have a higher charge / discharge speed ( Discharge in a short time, charge in a short time).

  As a method of measuring the internal resistance, it can be obtained by a direct current method. This measurement method is a method of calculating internal resistance by performing discharge at a constant current and performing the current density at the time of discharge at two or more levels. Specifically, the internal resistance is calculated from the relationship between the current density during discharge and the discharge start voltage.

According to the present embodiment, the internal resistance can be measured in a state where the capacitor is constructed as a capacitor or battery cell incorporating WO ₃ as an electrode. Further, since the diffusion channel also becomes a space for storing Li, about twice as much Li can be stored as compared with monoclinic WO ₃ . When the amount of Li that can be stored is expressed in the form of Li _x WO ₃ , the monoclinic crystal can satisfy x <0.67, whereas the hexagonal crystal structure can satisfy 0 <1.34. Therefore, the tungsten oxide powder preferably has a volume ratio of 50% or more, more preferably 90 to 100%, having a hexagonal crystal structure. If the hexagonal crystal structure can be made 50% by volume or more, the x value indicating the amount of Li can be made 0.67 or more. Note that the upper limit of the x value in Li _x WO ₃ is not particularly limited.

  The ratio of hexagonal crystals in the tungsten oxide powder can be determined from the intensity value of the XRD diffraction peak. Here, in order to identify the hexagonal crystal by the XRD diffraction method, it is necessary to match at least five diffraction peaks. From the low angle side, (100), (001), (110), (101), (200 ). Typically, 2θ is 14.01 ± 0.10 °, 27.80 ± 0.10 °, 24.39 ± 0.10 °, 24.86 ± 0.10 °, and 28.23 ± 0. 10 °.

  The ratio of hexagonal crystals can be determined by comparing these peak intensities with the peak intensities of crystal systems other than hexagonal crystals. Examples of crystals other than hexagonal crystals include monoclinic crystals and cubic crystals. In particular, when exposed to a high temperature of about 370 ° C. or higher, more preferably 500 ° C. or higher, monoclinic crystals tend to be formed.

  In the case of a monoclinic crystal, five peaks (002), (020), (200), (022), and (202) are detected. For example, when both hexagonal crystals and monoclinic crystals exist, the volume ratio of hexagonal crystals can be obtained by obtaining the strongest peak ratio of each. In order to obtain this volume ratio, the XRD diffraction intensity values of the three strongest peaks in each of the hexagonal and monoclinic crystal systems can be averaged and calculated based on a calibration curve previously measured in both crystal systems. . Here, calculation is performed using three peaks of (100), (001), and (200) as hexagonal crystals and three peaks of (002), (020), and (200) as monoclinic crystals. To do.

  The XRD analysis is performed with a Cu target, a tube voltage of 40 kV, and a tube current of 40 mA.

In addition, when the tungsten oxide powder is analyzed by Raman light, it is preferable that an intensity peak is detected at 690 ± 10 cm ⁻¹ and / or 780 ± 10 cm ⁻¹ . The peak at 780 ± 10 cm ⁻¹ is preferably a sharp peak. A sharp peak having a half width of 50 cm ⁻¹ or less is preferable. Half-width 50 cm ^-1, the more is 40 cm ^-1 or less, indicating that the crystallinity is good. Good crystallinity means that there are no crystal lattice distortions or defects. Due to the improvement in crystallinity, Li can be delivered more efficiently. Further, it is preferable that no intensity peak is detected at 950 ± 10 cm ⁻¹ . An intensity peak of 950 ± 10 cm ⁻¹ indicates the presence of a hydrate of tungsten oxide powder (WO ₃ ). If a hydrate is present, it may be unsuitable as an electrode material depending on the application.

In addition, if the crystallinity is insufficient or hydrates are mixed, the storage capacity is reduced. Also, depending on the application (battery type), there is a possibility that the charge / discharge cycle characteristics may be reduced. In other words, it is preferably a tungsten oxide (WO ₃ ) powder that has good crystallinity and does not contain hydrates. As a means for investigating the presence of such crystallinity and hydrate, Raman light spectroscopy is suitable.

The Raman spectroscopic analysis is performed by the following method. For the apparatus, PDP-320 manufactured by Photon Desing is used. Measurement conditions are: microscopic Raman, measurement magnification of 100 times, beam diameter of 1 μm or less, light source Ar ⁺ laser (wavelength 514.5 nm), laser power 0.5 mW (at tube), diffraction grating Single 600 gr / mm, cross slit 100 μm , Slit 100 μm, detector CCD / Roper 1340 channel. Under this condition, 100 to 1500 cm ⁻¹ is analyzed. The sample form can be measured as tungsten oxide particles.

The tungsten oxide powder preferably has a BET specific surface area of 1 m ² / g or more. When the BET specific surface area is less than 1 m ² / g, the particle size becomes larger than necessary, so that it may be difficult to make the volume ratio of 50% or more as described above hexagonal. Therefore, the BET specific surface area is preferably 3 m ² / g or more. In addition, although the upper limit of the BET specific surface area of tungsten oxide powder is not specifically limited, It is preferable that it is 60 m < ² > / g or less. In the case of tungsten oxide (WO ₃ ) powder having a hexagonal crystal structure, the diffusion rate of Li in the solid is high, so that the particle size is relatively large and the internal resistance can be reduced even with a low specific surface area.

In the case of the tungsten oxide (WO ₃ ) powder having a hexagonal crystal structure according to the embodiment, the powder may have pores. In this case, there is a possibility that the particle size and the specific surface area are not necessarily consistent. That is, even when the apparent particle size is large, the specific surface area may be large when pores are present inside. The particle diameter is preferably 100 μm or less from the relationship of the film thickness of the electrode layer.

  A metal oxide may be provided on the surface of the tungsten oxide powder. The metal oxide provided on the surface may be a part of the surface of the tungsten oxide powder or the entire surface. A porous electrode layer may be formed using tungsten oxide powder. At this time, if a metal oxide film is provided, the bonding strength between the tungsten oxide powders can be increased. When the bonding force is increased, the resistance of the bonding portion between the tungsten oxide powders of the porous electrode layer can be reduced. Metal oxides include indium oxide, yttrium oxide, titanium oxide, tin oxide, zirconium oxide, magnesium oxide, aluminum oxide, cerium oxide, thulium oxide, manganese oxide, tantalum oxide, niobium oxide, lanthanum oxide, ITO, and oxide. Examples thereof include scandium, samarium oxide, neodymium oxide, and gadolinium oxide. Among these, indium oxide and yttrium oxide are preferable.

  Further, a capacitor type power storage device is illustrated in FIG. 2 as an example of the power storage module. In the figure, reference numeral 10 denotes a capacitor type power storage device, 11 is an electrode layer (negative electrode side electrode layer), 12 is a negative electrode layer, 13 is a separator layer, 14 is a positive electrode layer, and 15 is an electrode layer (positive electrode side electrode layer). is there.

  The electrode layer 11 and the electrode layer 15 are made of a conductive metal such as an aluminum foil. A negative electrode layer 12 is provided on the electrode layer 11. The negative electrode layer 12 uses the battery electrode material according to the embodiment. At this time, a porous electrode layer made of tungsten oxide powder is preferably used as the battery electrode material. The porous electrode layer preferably has a thickness of 1 μm or more and a porosity of 20 to 80% by volume.

  Next, the separator layer 13 is disposed. The separator layer 13 is a layer in which the negative electrode layer 12 and the positive electrode layer 14 are arranged at regular intervals to provide a gap and impregnated with an electrolytic solution. The separator layer 13 is made of, for example, a polyethylene porous film, and is preferably impregnated with an electrolytic solution containing Li ions. In FIG. 2, a positive electrode layer 14 and an electrode layer 15 are provided below the separator layer 13.

The positive electrode layer 14 is formed of a porous layer made of a Li composite oxide such as LiCoO ₂ . Examples of the Li composite oxide include LiCoO ₂ , LiMnO ₂ , LiNiO _2, and those having a mixed composition thereof. The electrode layer 15 becomes a current collector layer.

  Moreover, various things, such as an organic solvent and an ionic liquid, are applicable as electrolyte solution. Examples of the organic solvent include propylene carbonate, ethylene carbonate, and γ-butyl lactone. Examples of the ionic liquid include ethyl methyl imidazolium bistrifluoromethanesulfonate.

  The capacitor type power storage device has such a laminated structure. In addition, the storage capacity can be improved by stacking a plurality of the stacked structures. Further, a long laminated structure may be wound to improve the storage capacity. In addition, when a capacitor is used, such a laminated structure is stored in a storage container (such as a metal can).

  Further, in order to produce the tungsten oxide powder having the hexagonal crystal structure, a synthesis method using a liquid phase reaction is preferable. There is a synthesis method using a plasma flame for producing tungsten oxide powder, but exposure to a high temperature of 500 ° C. or more is not preferable because the hexagonal crystal is likely to change to a monoclinic crystal. Therefore, it is preferable to use a low-temperature reaction using a liquid phase reaction and a heat treatment temperature of less than 500 ° C. during the production process. In order to further promote the growth in the liquid phase, a production method using a hydrothermal reaction under pressure is also possible.

Moreover, as a manufacturing method using a liquid phase reaction, there are various methods, but the following method is given as an example. Tungstic acid (H ₂ WO ₄ ) is used as a starting material, and the pH is adjusted using an alkaline solution such as sodium hydroxide (NaOH) and an acidic solution such as ammonium hydrogen carbonate (NH ₄ HCO ₃ ). Thereafter, heat treatment is carried out in an autoclave container (hydrothermal reaction) to promote the reaction and to produce. Alternatively, tungsten oxide can be precipitated by dissolving metallic tungsten with aqueous hydrogen peroxide and adjusting the pH with ammonia, hydrochloric acid, or the like. By subjecting the reaction product thus obtained to a heat treatment at a temperature of 200 ° C. or higher and 400 ° C. or lower, hexagonal WO ₃ having a reduced hydrate content can be obtained. Here, the reason why the temperature is 400 ° C. or lower is to avoid a phase change to a monoclinic crystal.

As starting materials, it is also effective to use Na ₂ WO ₄ , Li ₂ WO ₄ , (NH ₄ ) ₁₀ [H ₂ W ₁₂ O ₄₂ ] · 4H ₂ O, ATP (ammonium paratungstate), and the like. Two or more tungstic acids may be used as starting materials. In addition, after the liquid phase reaction, filtration, washing with water and drying are performed. A tungsten oxide (WO ₃ ) powder having a hexagonal crystal structure can be obtained by performing a liquid phase reaction and performing an appropriate heat treatment. In addition, the obtained tungsten oxide powder is sufficiently dried.

In the production of the Li _x WO ₃ powder, a ratio of tungsten oxide (WO ₃₎ powder having a hexagonal crystal structure, method of dipping in a solution containing Li ions. Further, a tungsten oxide (WO ₃ ) powder having a hexagonal crystal structure is formed into a porous electrode layer (thickness of 1 μm or more and a porosity of 20 to 80% by volume) and then immersed in a solution containing Li ions. You may perform a process.

With the power storage device as described above, the power storage capacity can be increased, and the charge / discharge speed can be increased. Further, the internal resistance of the porous electrode layer 20 [Omega · cm ² or less, and further to below the low resistance 15Ω · cm ^2. By reducing the internal resistance, charge / discharge speed can be increased. Therefore, it is possible to stabilize the output power of the natural energy power generation system.

  In recent years, the number of solar cells with a power storage function provided with a so-called storage battery is also increasing. This is because the solar cell is vulnerable to changes in the amount of sunlight, and unless electricity is frequently supplied from the storage battery, electricity is not supplied to the load (electrical device) and a shutdown state occurs. When the storage battery is repeatedly charged and discharged, the charge capacity decreases. Similarly, wind power generation is vulnerable to changes in the air volume, and unless electricity is frequently supplied from the storage battery, electricity is not supplied to the load (electric device) and a shutdown state occurs.

  Since the natural energy power generation system according to the present embodiment can stabilize the output power, the number of operations of the storage battery can also be reduced. Therefore, the frequency | count of use of a storage battery can be reduced by using the natural energy power generation system of embodiment as a natural energy power generation system which added the storage battery. As a result, it is possible to extend the life of a photovoltaic power generation system provided with a storage battery, or to reduce the size of the storage battery itself.

(Example)
(Solar power generation module)
As the first power generation module, a silicon-based solar cell with an output power of 210 W was prepared. A power generation module in which two first power generation modules are connected in series was used as a second power generation module.

(Power storage module)
A tungsten trioxide powder having a hexagonal crystal structure was prepared. The tungsten trioxide powder according to sample 1 has a BET specific surface area of 2 g / m ² , the tungsten trioxide powder according to sample 2 has a BET specific surface area of 5 g / m ^2, and the tungsten trioxide powder according to sample 3 has a BET specific surface area. was a 10 g / ^{m 2,} tungsten trioxide powder of sample 4 was a BET specific surface area 15 g / ^{m 2.} The composition of the tungsten trioxide powder was in the range of WO _{2.6 to 3.0} .

  Next, XRD analysis and Raman light analysis were performed on each tungsten trioxide powder. The ratio (volume%) of the hexagonal crystal structure in tungsten trioxide was investigated by XRD analysis.

  When the XRD analysis method is performed, five peaks (100), (001), (200), (101), and (200) are detected in the case of hexagonal crystal. In the case of a monoclinic crystal, five peaks (002), (020), (200), (022), and (202) are detected.

  In the case of having a constituent phase in which hexagonal crystal and monoclinic crystal are mixed, it can be determined by the ratio of the hexagonal strongest peak to the monoclinic strongest peak. The hexagonal crystal has an average value (average peak intensity) of three peaks of (100), (001), and (200), and the monoclinic crystal has three (002), (020), and (200). The average value of the peaks (average peak intensity) was determined. Measurement was performed using a calibration curve measured in advance.

Moreover, the presence or absence of a crystal structure or a hydrate can be confirmed by performing a Raman optical analysis method. Specifically, in the hexagonal crystal, an intensity peak is detected at 690 ± 10 cm ⁻¹ or / and 780 ± 10 cm ⁻¹ . In the monoclinic crystal, an intensity peak is detected at 720 ± 10 cm ⁻¹ or / and 800 ± 10 cm ⁻¹ . Among these, 690 ± 10 cm ^-1 hexagonal, since 720 ± 10 cm ^-1 is determined easily monoclinic, it is preferable to determine presence or absence of the two peaks. In the case of a hydrate, an intensity peak is detected at 950 ± 10 cm ⁻¹ .

  The results are shown in Table 1.

As is apparent from the measurement results shown in Table 1, Sample 1 was a mixture of hexagonal crystals and monoclinic crystals. Samples 2 to 4 were 100% hexagonal. In any of samples 1 to 4, no peak at 950 ± 10 cm ⁻¹ was observed by Raman optical analysis, and it was confirmed that no hydrate was present.

Next, acetylene black as a conductive additive and polyvinylidene difluoride (polyvinylidene fluoride) as a binder were mixed with tungsten trioxide powder (WO ₃ ) powder to prepare a paste. This paste was printed on a 15 μm-thick aluminum foil (negative electrode layer 11) and dried to obtain a negative electrode sheet (negative electrode layer 12). Using LiCoO ₂ powder as a positive electrode, a paste was prepared in the same manner as the above negative electrode, and applied to an aluminum foil (positive electrode side electrode layer 15) having a thickness of 15 μm and dried to prepare a positive electrode sheet (positive electrode layer 14). did. Further, WO ₃ mixing ratio of powder and acetylene black (weight ratio), WO ₃ powder: acetylene black = 100: 10. Further, the basis weight of the negative electrode material obtained by adding the WO ₃ powder and acetylene black was adjusted to 12 mg / cm ^2, and the film thickness after drying was 20 μm, and the porosity was 50%. In addition, the basis weight of the positive electrode material was set to an amount having a sufficient margin for the electric capacity of the negative electrode material.

  Moreover, the polyethylene porous membrane (film thickness of 20 micrometers) was used as a separator layer (separator layer 13). These electrode and separator layers were cut into 10 cm square and 14 layers were laminated, and then a tab for taking out current was welded. This laminate was incorporated into a laminate type cell and impregnated with an electrolytic solution, and then defoamed and sealed to produce capacitor type power storage devices (samples 1A to 4A). As the electrolytic solution, a solution obtained by dissolving LiPF6 as an electrolyte in an EC / DEC solution was used. EC is an abbreviation for Ethylene Carbonate, and DEC is an abbreviation for Diethyl Carbonate.

  Charging / discharging characteristics were investigated using the capacitor type power storage device. First, in order to measure electric capacity, a charge / discharge test was performed in a voltage range from 1.5 V to 3.0 V using a charge / discharge device. Charging was first performed in the constant current mode, and when 3.0V was reached, the mode shifted to the 3.0V constant voltage mode, and charging was continued until the current amount decreased to a constant value. After charging, the battery was discharged at a constant current, and the electric capacity of the capacitor type power storage device was determined from the electric capacity at the time of discharging. As the value of electric capacity, the energy capacity value (J) at the time of discharge was used.

Next, the internal resistance was measured by a direct current method. Discharging at a constant current was carried out under conditions where the amount of current was changed at two levels of 1 mA and 5 mA, and the internal resistance value (Ω · cm ² ) was determined from the relationship between each discharge start voltage and the amount of load current.

  Table 2 shows the initial electric capacity (storage capacity) and the internal resistance value.

  The power storage module including the power storage devices according to Samples 1A to 4A had a high storage capacity and a low internal resistance. Since the internal resistance is low, the charge / discharge speed can be increased.

(Examples 1-7 and Comparative Examples 1-2)
Next, the natural energy power generation systems according to Examples 1 to 7 shown in Table 3 were manufactured by connecting the power storage modules of Samples 1A to 4A in parallel to the first power generation module or the second power generation module. A diode for preventing a backflow from the power storage module to the power generation module was installed between the power generation module and the power storage module.

  In Comparative Examples 1 and 2, a battery without a power storage module was prepared. Comparative Example 1 is only the first power generation module, and Comparative Example 2 is only the second power generation module.

  Regarding the natural energy power generation systems according to Examples and Comparative Examples, the variation in output power was investigated. For the variation in output power, sunlight was irradiated for 60 minutes, and the average value (W) of the output power of the natural energy power generation system was obtained. Moreover, the variation showed the largest deviation (maximum fluctuation value) with respect to the average value in%. The reduction rate (%) was also obtained. The reduction rate (%) is 60 minutes per unit time, and the reduction rate (%) in 60 minutes = [(maximum output fluctuation width of the first power generation module (or second power generation module) −natural energy power generation according to the embodiment) The maximum output fluctuation range of the system) / the maximum output fluctuation range of the natural energy power generation system according to the example] × 100. The results are also shown in Table 3.

  As is clear from the results shown in Table 3 above, it was found that variations in output power were reduced in the natural energy power generation systems according to Examples 1 to 7. Moreover, while the output power graph of the comparative example 1 was shown in FIG. 3, the output power graph of Example 4 was shown in FIG. As shown in FIG. 4, it is clear that the natural energy power generation system according to the fourth embodiment realizes stabilization of output power even though the same power generation module is used.

  In particular, it has been found that variation can be reduced by using a power storage module having a large power storage capacity. In addition, a method of connecting a plurality of power storage modules in series to increase the power storage capacity is also effective. Further, by increasing the storage capacity (J) to 300 (seconds) × A (W) or more, and further to 350 (seconds) × A (W) or more, it is possible to suppress variations in the output power of the photovoltaic system. did it. This is because the capacitor-type power storage device according to the embodiment can cope with speeding up of charge and discharge.

  On the other hand, when the unit structure with the power storage module was not used as in Comparative Example 1 and Comparative Example 2, the variation in output power was large.

  As described above, the natural energy power generation system according to the embodiment can be a photovoltaic power generation system that is resistant to changes in the amount of sunlight. In addition, since the output power after stabilization can be supplied to the power conditioner, the burden on the power conditioner can be reduced.

(Wind power generation module)
A wind power generation facility with an output power of 400 W was prepared as a third power generation module. As a fourth power generation module, a wind power generation facility with an output power of 600 W was prepared.

(Power storage module)
Samples 1A to 4A described above were prepared.

(Storage battery module)
A lead storage battery having a storage capacity of 400 Wh was prepared for the third power generation module, while a lead storage battery having a storage capacity of 600 Wh was prepared for the fourth power generation module.

(Examples 8 to 11 and Comparative Examples 3 to 4)
Next, the natural energy power generation systems according to Examples 8 to 11 shown in Table 4 were manufactured by connecting the power storage modules of Samples 1A to 4A in parallel to the third power generation module or the fourth power generation module. A diode for preventing a backflow from the power storage module to the power generation module was installed between the power generation module and the power storage module.

  Note that Comparative Examples 3 to 4 were prepared without an electricity storage module. Comparative Example 3 is only the third power generation module, and Comparative Example 4 is only the fourth power generation module.

  Moreover, the storage battery module was connected to the natural energy power generation system which concerns on an Example and a comparative example, respectively.

  Regarding the natural energy power generation systems according to Examples and Comparative Examples, the variation in output power was investigated. For the variation in output power, wind power generation was performed for 60 minutes, and the average value (W) of the output power of the natural energy power generation system was obtained. Moreover, the variation showed the largest deviation (maximum fluctuation value) with respect to the average value in%.

  The reduction rate (%) was also obtained. The reduction rate (%) is 60 minutes per unit time, and the reduction rate (%) in 60 minutes = [(maximum output fluctuation width of the third power generation module (or fourth power generation module) −natural energy power generation according to the embodiment) The maximum output fluctuation range of the system) / the maximum output fluctuation range of the natural energy power generation system according to the example] × 100. The results are also shown in Table 4 below.

  As described above, the natural energy power generation system according to the present embodiment can be a natural energy power generation system that is resistant to air volume changes. Moreover, since the output power after stabilization can be supplied to a power conditioner, the burden of a power conditioner can be reduced.

  Next, the storage battery systems were connected to Examples 8 to 11 and Comparative Examples 3 to 4, respectively. Wind power generation was performed for 3 hours, and it was confirmed how many times the discharge from the storage battery system was performed during that time. The results are shown in Table 5.

  As described above, according to the natural energy power generation system according to the present embodiment, the number of discharges from the storage battery system can be reduced. As a result, since the number of times the storage battery system is used is reduced, it is possible to maintain long-term reliability as a whole natural energy power generation system.

  As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

1. Natural energy power generation system (photovoltaic power generation system, wind power generation system)
2 ... Power generation module 3 ... Power storage module 4 ... Diode 5 ... Power conditioner 6 ... Load 10 ... Capacitor type power storage device 11 ... Electrode layer (negative electrode layer)
DESCRIPTION OF SYMBOLS 12 ... Negative electrode layer 13 ... Separator layer 14 ... Positive electrode layer 15 ... Electrode layer (positive electrode side electrode layer)

Claims (5)

It has a power storage function including a power generation module having at least one power generation unit that converts natural energy into electric power, and a power storage module having at least one power storage device that stores part of the power converted by the power generation unit. In the natural energy power generation system,
Wherein the power generation module and the storage module are connected in parallel, by adding the output power from the power storage module to output power from the power generation module, Ri stabilization can der output power as a photovoltaic system, 60 Even if the minimum output is 0.7A or less or the maximum output is 1.3A or more with respect to the average value A (W) of the output of the power generation module per minute, it is possible to stabilize the output power as a natural energy power generation system. The output of the natural energy power generation system is in the range of A ± 0.25 A (W), the power storage device includes tungsten oxide powder as the porous electrode layer, and the porous electrode layer has a film thickness of A natural energy power generation system characterized by being 1 μm or more, a porosity of 20 to 80% by volume, and an internal resistance of 20 Ω · cm ² or less. Stem. The power storage capacity (J) of the power storage device is 300 (seconds) x A (W) or more, where A (W) is an average value of the output of the power generation module. Natural energy power generation system. The natural energy power generation system according to claim 1 or 2, wherein the tungsten oxide powder is a tungsten trioxide powder having a hexagonal crystal structure. The natural energy power generation system according to any one of claims 1 to 3 , wherein the natural energy is at least one of sunlight and wind power. The reduction rate represented by [(maximum output fluctuation width of natural energy power generation−maximum output fluctuation width of combined output) / maximum output fluctuation width of natural energy power generation] × 100 is 40% or more. The natural energy power generation system according to any one of 1 to 4.

Images