JP2011210890A - Photovoltaic power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power generator in which efficiency is less apt to be degraded, even if there is no movable part to track the sun, being no limit in a light condensing magnification ratio even with a simple configuration.SOLUTION: The photovoltaic power generator has a plurality of solar cells 2 arranged being spaced two-dimensionally, a first reflector portion 3 arranged between the solar cells 2, a condenser 4 arranged in the light receiving plane 21 side of the solar cells 2, a second reflector having a reflecting surface in a portion avoiding the optical path of the condenser 4, being arranged in a side facing the solar cells 2 of the condenser 4.

Description

  The present invention relates to a solar power generation device that converts sunlight into electrical energy.

As a solar power generation device that converts sunlight into electric energy, there is a concentrating solar cell using a solar cell with high conversion efficiency.
In a concentrating solar cell, sunlight is generally condensed onto the solar cell using a condensing lens.

However, it is difficult for a solar cell using a condensing lens to obtain its condensing magnification with a simple lens such as a single lens. On the other hand, if a solution is obtained by using a plurality of optical systems, it is disadvantageous in terms of cost.
Furthermore, since the sun moves with time, there is a problem that the efficiency is lowered.
In order to solve this problem, systems with a mechanism for tracking the sun have come to be seen.

Patent Document 1 discloses a concentrating solar cell module that collects light on a light receiving surface of a solar cell using an optical system such as a Fresnel lens.
When the solar cell module is condensed, the light intensity increases and the generated voltage increases. That is, the ratio of the output energy to the incident energy, that is, the conversion efficiency can be improved.

However, if the position of the sun changes depending on the time and season, the incident angle of sunlight on the solar cell module also changes in various ways. The efficiency may be reduced, and the solar cell may be out of position to generate power.
Therefore, in the prior art, it has been proposed to control the light receiving angle of the solar cell module using a tracking device so that the sunlight has an optimum incident angle (normal direction).

JP 2002-289896 A

  In a solar cell using a condensing lens, it is difficult to obtain a condensing magnification with a simple lens such as a single lens.

However, using a tracking device uses power for its control and drive itself. If the sunlight is weak due to the weather, etc., the power necessary for tracking will not be covered by its own electromotive force.
Moreover, since it is a device on the premise that it is installed outdoors, environmental resistance and durability are required. In some cases, it is considered that maintenance is required, which requires labor and cost.

  An object of the present invention is to provide a photovoltaic power generation apparatus that has no limitation on the light collecting magnification even with a simple configuration and that is less likely to lose efficiency even without a mechanical movable part that tracks the sun.

  The solar power generation device according to the first aspect of the present invention includes a plurality of solar cells that are two-dimensionally spaced apart, a first reflecting portion that is disposed between the solar cells, and the solar cell. A light collecting surface disposed on the light receiving surface side of the light collecting surface, a second reflecting portion disposed on a side facing the solar cell of the light collecting device and having a reflective surface in a portion avoiding the optical path of the light collecting device, Have

  Preferably, the condensing device is formed by arranging a plurality of funnel-shaped light condensing portions that are reduced in diameter toward the solar cell by the reflecting member.

  Preferably, the funnel-shaped light condensing part is set such that the central part side has a higher refractive index than the peripheral part side.

  Preferably, the light collecting device is formed of a microlens array.

  Preferably, the second reflecting portion has a concave shape having a surface top in a substantially normal direction of the light receiving surface of the solar cell.

  Preferably, a fluid is injected between the solar cell and the second reflecting portion.

  According to the present invention, it is possible to realize a photovoltaic power generation apparatus that has no limitation on the light collecting magnification even with a simple configuration and that is less likely to lose efficiency even without a mechanical movable part that tracks the sun.

It is a figure which shows typically the structural example of the solar power generation device which concerns on the 1st Embodiment of this invention. It is a figure which shows typically the general outline | summary of the condensing apparatus which concerns on this embodiment. It is a figure which shows typically the structure which filled the inside of the funnel-shaped part of the light condensing part which concerns on this embodiment with the transparent medium. It is a figure which shows the image of condensing by the condensing apparatus which functions as an optical trap which concerns on this embodiment. It is a figure which shows the image of condensing by the other condensing apparatus which functions as an optical trap which concerns on this embodiment. It is a figure for demonstrating the manufacturing method of the condensing device which concerns on this embodiment. It is a figure which shows typically the structural example of the solar power generation device which concerns on the 2nd Embodiment of this invention. It is a disassembled perspective view of the structure of the solar power generation device which concerns on the 3rd Embodiment of this invention. It is a disassembled perspective view which shows the structural example of the condensing apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating a configuration example of a photovoltaic power generation apparatus according to the first embodiment of the present invention.

  The solar power generation device 1 according to the first embodiment includes a plurality of solar cells 2, a first reflection unit 3, a light collection device 4 as an optical trap, a light guide unit 5, and a second reflection unit 6. As a main component. In FIG. 1, only one second reflecting portion 6 is schematically shown.

  A plurality of solar cells 2 are provided, and are arranged two-dimensionally on the main surface 11 of the solar cell substrate 10 with the light receiving surface 21 facing the light incident side.

Between the plurality of solar cells 2 on the solar cell substrate 10, a first reflecting portion 3 having a mirror reflecting function is disposed.
The first reflection unit 3 is focused and guided by the light collecting device 4, reflects light other than light received by the light receiving surface 2 of the solar cell 2 to the light collecting device 4 side, and further the light collecting device. It has a function of reflecting light on the four sides and reusing light.

  In the first embodiment, the light guide unit 5 is a space for guiding light between the light emitting surface 4 a side of the light collecting device 4 facing the main surface 11 of the solar cell substrate 10. Is formed.

  The condensing device 4 is disposed on the light receiving surface side of the solar cell 2 via the light guide unit 5, condenses sunlight SL, and is applied to the main surface side of the solar cell substrate 10, particularly on the light receiving surface 21 of the solar cell 2. It has a function of emitting the condensed light.

The condensing device 4 functions as a part of the optical trap and has a heat dissipation function.
Here, the optical trap refers to the direction in which sunlight is lit, generally passing or easily passing light from above, and reflecting light from the lower side, in this embodiment, from the solar cell substrate 10 side, or It means a structure having a structure that easily reflects.

Thus, the solar power generation device 1 of this embodiment adds the condensing device 4 as an optical trap above the solar cell 2, and the first reflection that is a mirror in the gap between the solar cells 2. It has a structure in which the part 3 is arranged.
With this structure, light from above passes through the light collecting device 4 that is an optical trap, and the light reaches the light receiving surface 21 of the solar cell 2 disposed below.
The light that has not reached the light receiving surface 21 of the solar cell 2 is reflected by the first reflecting unit 3 that is a mirror disposed in the gap between the solar cells 2 and travels upward, but the light collecting device 4 that is an optical trap. The light coming from the lower side on the surface 4a side is further reflected by the second reflecting portion or the like and returned to the lower solar cell substrate 10 side.

  Below, the specific structure and function of the condensing device 4 which functions as an optical trap are demonstrated.

  FIG. 2 is a diagram schematically showing an overall outline of the light collecting apparatus according to the present embodiment.

  The light collecting device 4 of FIG. 2 is formed by arranging a plurality of light condensing portions 42 on a base body 41 in a matrix.

The light collecting device 4 in FIG. 2 is incident on the light converging part 42 formed by arranging a plurality of funnel-shaped light condensing parts 42 in a matrix in which the opening diameter OR decreases toward the solar cell 2 side. The light rays hit the funnel-shaped wall and are guided to the solar cell side (downward).
The light condensing unit 42 is formed so that the aperture diameter is gradually reduced so that light rays incident from above are guided downward.
Further, the light exit surface side (lower surface side) of the light condensing unit 42 may be a flat mirror shape except for the opening. Thereby, the light from below is returned again to the solar cell side by one reflection.
Furthermore, the light condensing part 42 is good to fill the inside of the funnel-shaped part with a transparent material having a higher refractive index in the central part than in the peripheral part. The light that has entered the funnel-shaped part travels toward the center part with a high refractive index, and total reflection occurs at the interface from a member with a low refractive index to a member with a high refractive index. Can be guided downward.

  These configurations will be described with reference to FIGS.

  FIG. 3 is a diagram schematically showing a configuration in which the inside of the funnel-shaped portion of the light condensing portion according to the present embodiment is filled with a transparent medium.

As shown in FIG. 3, the light condensing part 42 may be filled with a transparent medium TP inside the funnel-shaped part. The light incident on the inside of the funnel-shaped part of the light condensing part 42 travels toward the central part TP1 having a high refractive index, and is totally reflected at the interface from the part TP2 having a low refractive index to the part TP1 having a high refractive index. Will occur.
For this reason, it becomes difficult for the light beam to return upward, and furthermore, the ratio of the opening diameter of the upper surface and the opening diameter of the lower surface of the funnel-shaped portion can be increased. .
This is a mirror which is the first reflecting portion 3 disposed in the gap between the solar cells 2 when the opening diameter of the upper surface is increased and more sunlight can be taken in, and when the opening diameter of the lower surface is decreased. This is because it is difficult for the reflected light to escape upward.

  FIG. 4 is a diagram illustrating a condensing device functioning as an optical trap according to the present embodiment and an image of condensing by the second reflecting unit.

In the solar power generation device 1, the ratio of the solar cells 2 on the solar cell substrate 10 corresponds to the light concentration.
The condensing device 4 shows a case where the solar cell side surface (lower surface) 42a of the light condensing unit 42 is a flat mirror that functions as the second reflecting unit 6 except for the opening. Manufacture is easily possible by using a flat mirror.

For example, an aluminum flat plate having good thermal conductivity is used as a base material.
This is because the heat generated by the reflection is efficiently released. The lower surface of this flat plate is mirrored. Furthermore, a funnel-shaped counterbore is provided. Preferably, the counterbore hole is filled with a transparent material having a higher refractive index at the center than at the periphery, as shown in FIG.

  FIG. 5 is a diagram illustrating an image of light collection by another light collecting device that functions as an optical trap according to the present embodiment.

The concentrating device 4A in FIG. 5 includes a concave mirror having a crest in the substantially normal direction (vertical line shape) of the light receiving surface 21 of each solar cell 2 except for the opening of the lower surface 42a of the light converging unit 42. It is shown that the shape is arranged as two reflecting portions 6a.
Compared with the flat mirror shown in FIG. 4, since the light is condensed in the vicinity of each solar cell, the light condensing degree can be improved.

  FIG. 6 is a view for explaining the method of manufacturing the light collecting device according to this embodiment.

The funnel-shaped transparent member formed on the base body 41 is manufactured as a member having a hollow core.
When molten resin or glass having a high refractive index is poured into the core, a transparent material having a higher refractive index in the central portion than in the peripheral portion as shown in FIG. 3 is obtained.
The base body 41 uses an aluminum flat plate having a good thermal conductivity as a base material. The lower surface of this flat plate is mirrored.
Then, a funnel-shaped counterbore is provided.
The counterbore hole is filled with the transparent member produced above.

According to the first embodiment, the solar power generation device 1 arranges a plurality of solar cells 2 in a two-dimensional manner with an interval between them, and arranges the first reflection unit 3 between the solar cells 2. A condensing device 4 in which a funnel shape for total reflection or total reflection is arranged is arranged on the light receiving surface 21 side of the battery 2, and a second reflecting portion (surface) 6 is arranged on the solar cell 2 side of the condensing device 4. It has the composition to do.
With this configuration, the light received by the condensing device 4 is guided to the solar cell 2 side, and the light that could not be received by the solar cell 2 is also repeatedly reflected between the first reflecting portion 3 and the second reflecting portion 6 to the solar cell. The light collection rate is improved so as to be guided to the second light receiving section.
Therefore, according to the present embodiment, it is possible to realize a photovoltaic power generation apparatus that is not easily reduced in efficiency even if there is no restriction on the light collecting magnification even with a simple configuration and there is no mechanical movable part that tracks the sun.

  FIG. 7 is a diagram schematically illustrating a configuration example of the solar power generation device according to the second embodiment of the present invention.

The solar power generation device 1A according to the present embodiment is different from the solar power generation device 1 according to the first embodiment as follows.
In 1st Embodiment, 5 A of light guide parts are formed as the space which guides light between the light-projection surface 4a side of the condensing device 4 which faces the main surface 11 of the solar cell substrate 10, and faces. Has been.
On the other hand, in the second embodiment, pure water is supplied by the cooling water circulator 8 in order to effectively dissipate the heat generated at each reflection to the light guide portion 5A formed by the gap. The cooling water 7 is circulated.

  By injecting cooling water 7 such as pure water into the gap between the light guides 5A, light transmission loss at the interface between the cooling water and the light exit surface 42a of the light collecting part 42 of the light collecting device is reduced. It becomes possible.

  Other configurations are the same as those of the first embodiment, and the same effects as those of the above-described first embodiment can also be obtained.

FIGS. 8A and 8B are diagrams schematically illustrating a configuration example of a solar power generation device according to the third embodiment of the present invention.
FIG. 8A shows a condensing state when incident light is incident substantially vertically, and FIG. 8B shows a condensing state when incident light is incident with an inclination.

  The solar power generation device 1B according to the third embodiment is formed by microlenses 420 in which light condensing units 42B functioning as optical traps of the condensing device 4B are arranged in an array.

The mirror as the second reflecting portion 6B below the microlens 420 is opened so as not to block incident light.
Light that is not directly incident on the solar cell 2 is also repeatedly reflected from the mirror as the first reflecting portion 3 on the substrate and guided to the light receiving surface 21 of the solar cell 2.

  FIG. 9 is an exploded perspective view illustrating a configuration example of the light collecting device according to the third embodiment.

A condensing member 400 in which condensing optical systems are arranged without a gap is disposed on the substrate 10 on which the solar cells 2 are arranged at intervals.
The condensing optical system arranged on the condensing member 400 may be a microlens type, a funnel type, or a mixture of them. An opening 410 corresponding to the light emitting part of the light condensing part is formed on the lower surface 400a of the condensing member 400, and a mirror as the second reflecting part 6B is formed therebetween.

  DESCRIPTION OF SYMBOLS 1 ... Solar power generation device, 2 ... Solar cell, 3 ... 1st reflection part, 4 ... Condensing apparatus, 5 ... Light guide part, 6 ... 2nd reflection Part, 7 ... cooling water.

Claims (6)

A plurality of solar cells arranged two-dimensionally apart from each other;
A first reflecting portion disposed between the solar cells;
A light collecting device disposed on the light receiving surface side of the solar cell;
A second reflecting portion disposed on the concentrating device facing the solar cell and having a reflecting surface in a portion avoiding the optical path of the concentrating device;
A solar power generation apparatus having The light collecting device is:
The solar power generation device according to claim 1, wherein a plurality of funnel-shaped light condensing portions whose diameter decreases toward the solar cell side by the reflecting member are arranged side by side. The funnel-shaped light condensing part is
The solar power generation device according to claim 2, wherein the center side is set to have a higher refractive index than the peripheral side. The light collecting device is:
The solar power generation device according to claim 1, wherein the photovoltaic power generation device is formed of a microlens array. The second reflecting portion is
The solar power generation device according to any one of claims 1 to 4, wherein the solar power generation device has a concave shape having a top surface in a substantially normal direction of a light receiving surface of the solar cell. The solar power generation device according to any one of claims 1 to 5, wherein a fluid is injected between the solar cell and the second reflecting portion.

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