JP2018026990A - Optical power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase working efficiency of an optical power generator.SOLUTION: An optical power generation module 4 converts an optical energy into an electric power by using a photovoltaic effect. An optical power generation module 5 converts the optical energy into the electric power by using the photovoltaic effect, and an optical power conversion characteristic is different from that of the optical power generation module 4. A switching mechanism 6 switches the optical power generation modules 4 and 5 as an incident destination of an external light. During a high illuminance time in a daytime when sufficient photovoltaic can be obtained, the optical power generation module 4 is selected, and the optical power generation module 5 is selected during a low illuminance time in a rainy day or a night. Thus, the optical power generation modules 4 and 5 are suitably selected depending on an illuminance state of the external light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photovoltaic device that converts light energy into electric power.

  Conventional solar power generation operates only during a limited time of the day (daytime), and the power generation efficiency varies greatly depending on the weather and season. Therefore, at present, photovoltaic power generation is not suitable as a base power source, that is, a power source that supplies a certain amount of power throughout the year. Further, the conventional indoor photovoltaic power generation has a problem that its practicality is low because of its low power conversion efficiency.

  Patent Document 1 discloses a charging device that can effectively use solar energy over a wide range from a low illuminance region to a high illuminance region. This charging device has a power conversion function for converting and outputting the power generation energy of the solar cell, and a switch function for outputting the power generation energy of the solar cell without conversion, and depending on the illuminance received by the solar cell, these charging devices Switch functions. That is, when the illumination is low, the power conversion function is stopped by switching to the switch function. Thereby, since loss and power consumption accompanying power conversion hardly occur, it is possible to charge the storage element while saving power consumption. On the other hand, when the illumination is high, the power conversion function is switched. Thereby, it can charge efficiently so that the output electric power of a solar cell may become the maximum.

Japanese Patent Laid-Open No. 11-46457

  An object of the present invention is to increase the operating rate of the photovoltaic power generation apparatus.

  In order to solve this problem, the present invention provides a photovoltaic device having a first photovoltaic module, a second photovoltaic module, and a switching mechanism. The first photovoltaic module converts light energy into electric power using the photovoltaic effect. The second photovoltaic module uses the photovoltaic effect to convert light energy into electric power and has a photoelectric conversion characteristic different from that of the first photovoltaic module. The switching mechanism switches between the first photovoltaic module and the second photovoltaic module as an incident destination of external light.

  Here, in the present invention, the first photovoltaic power generation module is a photovoltaic power generation module, and the second photovoltaic power generation module is lower than the photovoltaic power generation module at low illuminance lower than daytime outdoors. It is preferable that the module has a high photoelectric conversion efficiency, and more preferably, the second photovoltaic module is composed of an organic semiconductor element or a dye-sensitized element. Moreover, in this invention, it further has the wavelength conversion film which is provided in the optical path which guides external light to a 2nd photovoltaic module, and converts external light into the wavelength suitable for the utilization wavelength range of a 2nd photovoltaic module. Is preferred.

  In the present invention, the switching mechanism may include an installation base and a drive mechanism. The installation table has a first installation surface on which the first photovoltaic module is installed, and a second installation surface on which the second photovoltaic module is installed. The drive mechanism displaces the installation table to position one of the first installation surface and the second installation surface on the optical path of the external light. In the present invention, a light collecting mechanism for collecting external light may be further provided. In this case, the installation base is disposed on the optical path of the external light emitted from the light collecting mechanism, and is displaced in the rotational direction by the driving mechanism via the rotating shaft. The rotating shaft is eccentrically attached to the installation base so that the distance from the rotating shaft to the first photovoltaic module is different from the distance from the rotating shaft to the second photovoltaic module.

  In the present invention, the switching mechanism includes an optical member that switches between a first optical path that guides external light to the first photovoltaic module and a second optical path that guides external light to the second photovoltaic module, and an optical member And a drive mechanism for displacing.

  In the present invention, an external light sensor that detects the illuminance, wavelength, or spectrum of external light may be further provided. In this case, the switching mechanism switches between the first photovoltaic module and the second photovoltaic module according to the illuminance, wavelength, or spectrum detected by the external light sensor.

  According to the present invention, the first and second photovoltaic modules having different photoelectric conversion characteristics are provided, and these modules are switched as an incident destination of external light. By selecting a photovoltaic module suitable for the situation of external light, the operating rate of the photovoltaic apparatus as a whole can be increased.

1 is an external perspective view of a photovoltaic device according to a first embodiment. Photovoltaic generator block diagram Illustration of photovoltaic power generation at high illuminance Illustration of photovoltaic power generation at low illuminance The figure which shows the installation stand which concerns on 2nd Embodiment The block diagram of the photovoltaic device which concerns on 3rd Embodiment

(First embodiment)
FIG. 1 is an external perspective view of the photovoltaic device according to the present embodiment. The photovoltaic device 1 is mainly composed of a housing 2, a condensing mechanism 3, a plurality of photovoltaic modules 4, 5, and a switching mechanism 6. The housing 2 is a cylindrical member formed of a transparent member such as allyl, and has a high electromagnetic wave reflectivity on its inner peripheral surface so as to cope with the incidence of external light obliquely from above. For example, a film-like mirror or a half mirror is attached over the entire circumference. A condensing mechanism 3 that collects external light incident from above and guides it downward is attached to the upper opening of the housing 2. The condensing mechanism 3 is provided in order to ensure a constant power output even in a situation where the illuminance is low while reducing the cost, and a plano-convex lens can be typically used.

  In the lower opening of the housing 2, a plurality of photovoltaic modules 4, 5 that convert light energy of external light collected by the light collecting mechanism 3 into electric power using the photovoltaic effect are arranged. These photovoltaic modules 4 and 5 are, for example, one for photovoltaic modules and the other for modules with higher photoelectric conversion efficiency than photovoltaic modules at low illuminance lower than daytime outdoor illumination The photoelectric conversion characteristics are different. The switching mechanism 6 switches the photovoltaic modules 4 and 5 as incident destinations of external light that has passed through the light collecting mechanism 3. Photovoltaic modules 4 and 5 suitable for the illuminance condition of outside light are selected, such as the photovoltaic module 4 at high illuminance during the day when sufficient sunlight can be obtained, and the photovoltaic module 5 at low illuminance such as rainy weather or nighttime. Thus, the operation rate of the photovoltaic device 1 as a whole can be increased, and the restrictions on the weather and the operation time can be effectively relaxed. The housing 2 incorporates sensors and a drive system which will be described later.

  FIG. 2 is a block diagram of the photovoltaic device 1. In the present embodiment, the switching mechanism 6 that switches between the photovoltaic modules 4 and 5 is mainly configured by an installation base 6a and a drive mechanism 6b. The installation base 6 a has a disk shape smaller in diameter than the inner periphery of the housing 2, and is disposed on the optical path of the external light emitted from the light collecting mechanism 3. The photovoltaic modules 4 and 5 are respectively installed on the upper and lower surfaces (installation surfaces) of the installation table 6a. A wavelength conversion film 7 is provided immediately above the photovoltaic module 5 in order to convert external light into a wavelength suitable for the use wavelength range of the photovoltaic module 5. In the present embodiment, the wavelength conversion film 7 is provided only on the optical path of one photovoltaic module 5 in order to improve the power generation efficiency particularly at low illuminance. You may provide the wavelength conversion film 7 in this.

  Moreover, the installation base 6a is attached to the housing | casing 2 via the rotating shaft 6c, and can be displaced to a rotation direction. The drive mechanism 6b is arranged so that either the installation surface on the photovoltaic module 4 side or the installation surface on the photovoltaic module 5 side faces the condensing mechanism 3, in other words, the outer surface condensed by the condensing mechanism 3 The installation base 6a is displaced in the rotational direction so as to be positioned on the optical path of light. As the drive mechanism 6b, a known actuator such as a solenoid using an electromagnetic action or a servo motor using a dynamic action can be widely used. Further, the photovoltaic modules 4, 5 and the switching mechanism 6 may be integrated as one unit using MEMS (Micro Electro Mechanical Systems).

  The rotating shaft 6c is mounted eccentrically on the installation base 6a. Thereby, the distance D1 from the rotating shaft 6c to the photovoltaic module 4 and the distance D2 from the rotating shaft 6c to the photovoltaic module 5 are different. The reason for decentering in this way is to change the distance from the lens focal point for each of the photovoltaic modules 4 and 5 so that external light is incident at a light collection rate suitable for the characteristics of the photovoltaic modules 4 and 5. In the present embodiment, the distance D1 of the photovoltaic module 4 is set to be greater than the distance D2 of the photovoltaic module 5.

  The external light sensor 8 detects the illuminance of external light incident on the photovoltaic device 1. Switching between the photovoltaic modules 4 and 5 is performed according to the illuminance of external light detected by the external light sensor 8. For example, when the detected illuminance is higher than a predetermined threshold (for example, 5000 lux) (at high illuminance), the photovoltaic module 4 is selected, and when this illuminance is lower than the threshold (at low illuminance), The photovoltaic module 5 is selected. Further, this switching may be performed based on a timepiece built in the photovoltaic power generation apparatus 1. For example, the photovoltaic module 4 is selected during the time from sunrise to sunset, and the photovoltaic module 5 is selected during the night. Further, by providing the photovoltaic device 1 with an internet connection environment, the photovoltaic modules 4 and 5 may be switched based on information such as a weather forecast site. Note that the photovoltaic modules 4 and 5 may be switched by the user himself / herself through the operation of a switch.

  The electric power obtained by the photovoltaic modules 4 and 5 is collected by the external battery 9. Further, particularly during summer days, a large amount of heat is generated by the light collection by the light collection mechanism 3. Therefore, the heat generated in the installation base 6a is absorbed by a material having a high thermal diffusion coefficient, and electricity is generated by the external boiler 10 using this as a heat source. The electric power thus obtained is also collected by the battery 9.

  FIG. 3 is an explanatory diagram of photovoltaic power generation at high illuminance. The external light at high illuminance is typically sunlight having a wavelength range of 300 to 3000 nm, and the assumed illuminance is about 10,000 to 100,000 lux (daytime outdoor illuminance). At high illuminance, the photovoltaic module 4 faces the condensing mechanism 3, and external light collected by the condensing mechanism 3 is received by the photovoltaic module 4. In addition, the photovoltaic module 4 is located at a position away from the focal point F of the light collecting mechanism 3 by the distance D1 from the rotation axis. Thereby, since external light injects into the photovoltaic module 4 with a comparatively low condensing rate, the excessive heat_generation | fever by condensing is suppressed.

  As the photovoltaic module 4, an element having high photoelectric conversion efficiency at high illuminance, for example, a module constituted by a compound semiconductor element (multijunction element or the like) can be used. The use wavelength range is about 300 to 1200 nm, and the assumed illuminance is about 5,000 to 100,000 lux.

  The power generation efficiency of the photovoltaic module 4 mainly depends on two factors. The first is the width of the light absorption wavelength region. The wavelength range of sunlight and artificial light in urban areas is approximately 300 to 3000 nm, but generally a photovoltaic element can be absorbed (available for power generation) with a wide range of about 350 to 1300 nm and a narrow range of 400 nm. It is about ~ 800 nm. Even if the wavelength range that can be simply absorbed is wide, as will be described later, those having a quantum efficiency at each wavelength generally have low power generation efficiency. Second is the quantum efficiency at each wavelength. Due to the principle of each power generating element, there are a wavelength range that is good (high quantum efficiency) and a wavelength range that is not good (low quantum efficiency) for each type of photovoltaic element. The power generation efficiency is good when the wave of quantum efficiency at each wavelength follows the spectral distribution of sunlight or artificial light in urban areas as much as possible.

  Further, as the photovoltaic module 4, it is preferable to use a power generation element designed to withstand high output. For this purpose, the following two elements are important. First, because of the structure of the power generation element, how far it can withstand the process of “photoelectric phenomenon → current extraction” per unit time. A device that has a structure in which a current extraction cycle is performed by a reduction reaction of an electrolyte solution, such as a dye-sensitized element or an organic semiconductor element, is difficult to withstand high output because the reduction reaction (ion diffusion rate) cannot catch up. It is done. Second, as a fate of photovoltaic power generation due to light collection, a large amount of heat may be condensed in a narrow range. Therefore, it is considered that a structure having a weak point in heat resistance is difficult to withstand high output. In addition, a silicon-based material whose photoelectric conversion efficiency is remarkably lowered with an increase in temperature is not preferable.

  From the above, the compound semiconductor system “III-V group” multi-junction element is suitable for the photovoltaic module 4 at present. However, it is not limited to this type of element, and it is needless to say that it can be used as the photovoltaic module 4 as long as it has a high power generation efficiency and can withstand a high output.

  FIG. 4 is an explanatory diagram of photovoltaic power generation at low illuminance. The external light at low illuminance is typically artificial light in urban areas having a wavelength range of about 300 to 3000 nm, and the assumed illuminance is 10 to 10,000 lux (illuminance outside after sunset). When the illuminance is low, the photovoltaic module 5 faces the condensing mechanism 3, and external light collected by the condensing mechanism 3 is received by the photovoltaic module 5 through the wavelength conversion film 7 located on the optical path. Is done. Further, the photovoltaic module 5 is positioned at a position closer to the focal point F of the light collecting mechanism 3 by the amount that the distance D2 from the rotation axis is small. Thereby, since external light is incident on the photovoltaic module 5 with a relatively high condensing rate, a constant power generation efficiency can be obtained even at low illuminance.

  As the photovoltaic module 5, an element that maintains a constant photoelectric conversion efficiency even at low illuminance, for example, a module constituted by an organic semiconductor element, a dye-sensitized element, or the like is used. The use wavelength range is about 300 to 1500 nm, and the assumed illuminance is about 10 to 5,000 lux. Furthermore, the wavelength conversion film 7 converts the wavelength range of 1200 nm or more and the wavelength range of 350 nm or less into 350 to 1200 nm wavelength range in the incident external light.

  As the photovoltaic module 5, it is preferable to use a module that maintains constant power generation efficiency even at low illuminance (or when the incident light energy density is low). The power generation efficiency at low illumination depends mainly on two factors. First, as with the photovoltaic module 4, the width of the light absorption wavelength region and the quantum efficiency at each wavelength. Second, even when the light energy density is low, the power generation efficiency is unlikely to decrease. The current mainstream silicon-based power generation element has a characteristic that when the incident light energy density is low, the power generation efficiency is significantly reduced. On the other hand, dye-sensitized elements and organic semiconductor elements have a small correlation between light energy density and power generation efficiency due to their characteristics. This means that the power generation efficiency is unlikely to decrease even when the light energy density is low.

  From the above, currently suitable for the photovoltaic module 5 are dye-sensitized and organic semiconductor-based power generating elements. However, it is not limited to these types of elements, and it can be used as the photovoltaic module 5 as long as the photoelectric conversion efficiency is such that it can generate power effectively even when the light energy density is low. Nor.

  As described above, according to the present embodiment, a plurality of types of photovoltaic modules 4 and 5 having different photoelectric conversion characteristics with respect to illuminance are provided, and these modules 4 and 5 are switched as external light incident destinations. By selecting the photovoltaic modules 4 and 5 suitable for the illuminance situation of external light, it is possible to increase the operating rate of the photovoltaic power generation apparatus 1 as a whole, and it is possible to effectively alleviate restrictions on weather and operating hours. In particular, solar power generation modules are selected by selecting solar power modules during daytime high illuminance, and by selecting different types of modules that have a certain photoelectric conversion efficiency at low illuminance at night when it is difficult to generate power using solar power generation modules. Can be complemented effectively. Thereby, the possibility of using the photovoltaic device 1 as a base power source can be increased.

  Further, according to the present embodiment, the photovoltaic modules 4, 5 are switched on the same plane by switching the photovoltaic modules 4, 5 by displacing the installation base 6a in the rotation direction. Thus, the photovoltaic device 1 can be downsized. However, if it is not necessary to consider this point, the photovoltaic modules 4 and 5 are arranged on the same plane of the installation table 6a, and the installation table 6a is slid in the horizontal direction by the drive mechanism 6b. , 5 may be switched.

(Second Embodiment)
FIG. 5 is a diagram illustrating an installation base according to the second embodiment. The installation base 6d has a polygonal cross section, and the photovoltaic modules 4, 5, and 11 are installed on the respective surfaces. The rotating shaft 6c is mounted eccentrically on the installation base 6d, and the distance D1 from the rotating shaft 6c to the photovoltaic module 4, the distance D2 from the rotating shaft 6c to the photovoltaic module 5, and the photovoltaic power generation from the rotating shaft 6c. The distance D3 to the module 11 is different. Note that the same members as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted here.

  According to the present embodiment, in addition to the same effects as those of the first embodiment, outside light can be obtained without increasing the size of the photovoltaic power generation device 1 especially for the three or more photovoltaic power generation modules 4, 5, and 11. Can be switched to suit the illuminance situation.

(Third embodiment)
In the present embodiment, the photovoltaic modules 4, 5 and the like are switched by changing the optical path of external light instead of mechanical displacement of the installation bases 6a, 6d. FIG. 6 is a block diagram of a photovoltaic power generation apparatus according to the third embodiment. Note that the same members as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted here.

  Unlike the above-described embodiments, the installation base 6e is fixed, and the photovoltaic modules 4 and 5 are installed on different installation surfaces. The path of the external light condensed by the condensing mechanism 3 is switched between the first optical path and the second optical path according to the angle of the movable mirror 12 that is an optical member. That is, when the movable mirror 12 is positioned at the first angle, the external light is guided to the photovoltaic module 4 through the first optical path including the movable mirror 12 and the first fixed mirror 13a. When the movable mirror 12 is positioned at the second angle, the external light is guided to the photovoltaic module 5 through the second optical path including the movable mirror 12 and the second fixed mirror 13b. The drive mechanism 6f displaces the movable mirror 12 in the rotational direction, and sets the first angle or the second angle. As the drive mechanism 6f, a well-known drive mechanism using an electromagnetic action or a mechanical action can be widely used as in the drive mechanism 6b described above.

  According to the present embodiment, the same effect as that of the first embodiment can be obtained by displacing the movable mirror 12 and switching the photovoltaic modules 4 and 5.

  In each of the above-described embodiments, an example using a photovoltaic module that generates power from light (visible light) has been described, but recently, a photovoltaic module that generates power from infrared light or ultraviolet light has also been proposed. -It has been developed, and the present invention can also use these photovoltaic modules. For example, a solar cell developed by International Research Institute for Advanced Technology uses a dye-sensitized element, which absorbs invisible infrared light by a crystal and transmits it to the dye to generate electricity. Dye-sensitized solar cells jointly developed by Tanaka Kikinzoku and the University of Tokyo generate power in a wide wavelength range from the ultraviolet region to the infrared region. In this specification, “light” as an input for power generation includes a wide range of electromagnetic waves that can generate power using the photovoltaic effect, including visible light, infrared light, ultraviolet light, and the like. Defined.

  Moreover, in each embodiment mentioned above, you may switch photovoltaic modules 4, 5 grade | etc., According to the wavelength of external light instead of the illumination intensity of external light. In this case, when the wavelength of the external light is detected by the external light sensor 8 and the detected wavelength is larger than a predetermined threshold value (at the long wavelength), one of the photovoltaic modules 4 and 5 is selected, and this wavelength Is equal to or less than the threshold (when the wavelength is short), the other of the photovoltaic modules 4 and 5 is selected. The photovoltaic modules 4 and 5 have different photoelectric conversion characteristics with respect to the wavelength. Thereby, in the situation where the wavelength band of external light changes, the operation rate as the whole photovoltaic power generation apparatus 1 can be raised. Furthermore, the spectrum of external light may be detected by the external light sensor 8, and the photovoltaic modules 4, 5, etc. may be switched accordingly. The photovoltaic modules 4 and 5 have different photoelectric conversion characteristics with respect to the spectrum. Thereby, in the situation where the spectrum of external light changes, the operation rate as the whole photovoltaic power generator 1 can be raised.

DESCRIPTION OF SYMBOLS 1 Photoelectric generator 2 Case 3 Condensing mechanism 4, 5, 11 Photovoltaic module 6 Switching mechanism 6a, 6d, 6e Installation base 6b, 6f Drive mechanism 6c Rotating shaft 7 Wavelength conversion film 8 External light sensor 9 Battery 10 Boiler 12 Movable mirror 13a, 13b Fixed mirror

According to the present invention, the first and second photovoltaic modules having different photoelectric conversion characteristics are provided, and these modules are switched as an incident destination of external light. By selecting a photovoltaic module suitable for the situation of external light, the operating rate of the photovoltaic apparatus as a whole can be increased. In particular, when the rotating shaft is eccentrically attached to the installation base, external light can be incident at a light collection rate suitable for the characteristics of the first and second photovoltaic modules.

Claims (8)

In the photovoltaic device,
A first photovoltaic module that converts light energy into electrical power using the photovoltaic effect;
A second photovoltaic module that converts light energy into electric power by utilizing the photovoltaic effect, and having a photoelectric conversion characteristic different from that of the first photovoltaic module;
A photovoltaic power generation apparatus comprising: a switching mechanism that switches between the first photovoltaic power generation module and the second photovoltaic power generation module as an incident destination of external light. The first photovoltaic module is a photovoltaic module,
2. The light according to claim 1, wherein the second photovoltaic module is a module having a higher photoelectric conversion efficiency than the photovoltaic module when the illuminance is lower than that of outdoors during the daytime. Power generation device.   The photovoltaic device according to claim 2, wherein the second photovoltaic module comprises an organic semiconductor element or a dye-sensitized element.   It further includes a wavelength conversion film that is provided in an optical path that guides external light to the second photovoltaic module, and that converts the ambient light to a wavelength that conforms to a use wavelength range of the second photovoltaic module. The photovoltaic device according to claim 3. The switching mechanism is
An installation table having a first installation surface on which the first photovoltaic module is installed, and a second installation surface on which the second photovoltaic module is installed;
5. The driving mechanism according to claim 1, further comprising: a driving mechanism configured to position either the first installation surface or the second installation surface on an optical path of external light by displacing the installation table. A photovoltaic device described in any of the above. It further has a light collecting mechanism for collecting outside light,
The installation base is disposed on the optical path of the external light emitted from the light collecting mechanism, and is displaced in the rotational direction by the drive mechanism via the rotation shaft.
The rotating shaft is eccentrically attached to the installation base so that a distance from the rotating shaft to the first photovoltaic module is different from a distance from the rotating shaft to the second photovoltaic module. The photovoltaic power generator according to claim 5, wherein: The switching mechanism includes an optical member that switches between a first optical path that guides external light to the first photovoltaic module and a second optical path that guides external light to the second photovoltaic module;
The photovoltaic device according to claim 1, wherein the photovoltaic device is a drive mechanism that displaces the optical member. An external light sensor for detecting the illuminance, wavelength or spectrum of the external light;
The switching mechanism switches between the first photovoltaic module and the second photovoltaic module according to the illuminance, wavelength, or spectrum detected by the external light sensor. The photovoltaic device described in any one of.

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