JPH07302927A - Solar cell device - Google Patents

Abstract

(57) [Summary] [Object] To provide a solar cell device that solves various problems of a concentrating-type tracking solar cell device, is simple, and has a large effect of increasing the amount of incident sunlight. A solar cell 1 for receiving the reflected light of the light reflector 2 is arranged on a flat light reflector 2, and the light receiving surface of the solar cell 1 is reflected by the light reflector 2. It is characterized in that it is substantially perpendicular to the surface and is rotatable about the vertical axis of the reflecting surface of the light reflector 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell device in which a light reflector and a solar cell are combined in order to increase the amount of light incident on the light receiving surface of the solar cell.

[0002]

2. Description of the Related Art In general, a tracking type solar cell device constructed so that the light receiving surface of the solar cell can be tracked as the sun moves from east to west, has a fixed light receiving surface of the solar cell. 30 per day compared to solar cells that generate electricity
It is known that the amount of power generation can be increased by about 50%. In addition, such tracking solar cell device is provided with an incident light amount increasing means such as a lens and a reflecting mirror as shown in FIGS. 2 (a), 2 (b), 3 (a) and 3 (b). Thus, it is possible to increase the amount of solar power generation almost in proportion to the amount of collected light.

That is, as shown in FIG. 2A, when a circular Fresnel lens L1 having a large number of concentric lens regions is used as an incident light amount increasing means, the lens L1 is used.
The light h transmitted through is condensed at the focal point f1 of the lens L1, and the amount of power generation can be increased in this condensing region.
This effect is the same as in the circular parabolic mirror M1 as shown in FIG. 3A, and the light h reflected by the mirror M1 is h.
Is focused on the focal point f3, and the amount of power generation can be increased in this focusing region.

Further, as shown in FIG. 2B, when a linear Fresnel lens in which a large number of lens regions are linearly formed in parallel is used as the incident amount increasing means, the light h transmitted through the lens L2 is The light is focused on the focal line f2 of the lens L2, and the amount of power generation can be increased in this focus area. This effect is the same as in the gutter-shaped (linear) parabolic mirror M2 as shown in FIG. 3B, and the light h reflected by the mirror M2 is focused on the focal line f4. The amount of power generation can be increased in the area ("Latest solar power generation technology" edited by Keihiro Hamakawa, Maki Shoten, published July 1, 1984,
See p.111 to p.112).

However, in the case of the solar cell device using the high-magnification condensing type incident light amount increasing means as described above, since the condensing area is extremely narrow, it is necessary to track the sun position with extremely high accuracy. However, it is impossible to form a light-collecting region with a high power generation amount or to form a light-collecting region on the light receiving surface of a desired solar cell, and it is not possible to sufficiently exert its function. For this reason, for example, two-axis tracking control under computer control is required, and a cooling mechanism for cooling the heat generated by light collection is required.
Inevitably the device becomes complicated and large.

A solar cell device in which the amount of incident light is increased by tilting a side mirror or the like at a predetermined angle in the vicinity of the light receiving surface of the solar cell is conceivable. In such a case, tracking of the sun position is compared. Although it may be rough, even if a large-scale side mirror is used, there is a problem in that the condensing magnification is low and a sufficient increase in power generation cannot be expected.

Therefore, an object of the present invention is to solve the problems of the concentrating type tracking solar cell device and to provide a solar cell device which is simple and has a large effect of increasing the amount of incident sunlight. .

[0008]

In order to achieve the above object, the solar cell device of the present invention comprises a flat light reflector and a solar cell for receiving the reflected light of the light reflector. It is characterized in that the light receiving surface of the solar cell is substantially perpendicular to the reflecting surface of the light reflector and is rotatable about the vertical axis of the reflecting surface of the light reflector.

At the north latitude of 35 ° (near Kyoto, Japan), the sun altitude in the morning, evening and winter is very low. In such low solar altitude, the light receiving surface of the solar cell is more than the solar radiation on the horizontal plane. However, the amount of solar radiation on the vertical surface is higher. This tendency becomes more remarkable as the latitude increases. Therefore, in the present invention, the light receiving surface of the solar cell is basically arranged so as to be in a positional relationship perpendicular to the reflection surface of the light reflector, and sunlight tracking can be performed by a single rotation axis. I am supposed to. Note that the reflecting surface of the light reflector does not always coincide with the horizontal plane, and may be tilted in any of north, south, east, and west directions, for example.

Further, the solar cell device of the present invention is constructed such that the reflecting surface of the light reflector is located in front of and below the light receiving surface of the solar cell. In other words, the light receiving surface of the solar cell is rotated by one axis of rotation, and it is rotated about 180 ° from east to west in one day. To a distance, for example 35 ° north latitude
If the latitude is higher, the height of the light receiving surface of the solar cell (vertical width)
It is preferable that the reflective surface is formed 2.5 times or more.
Further, in the southward direction from the rotation axis, it is advisable to provide a reflecting surface up to a position where the reflected light reaches the upper end of the light receiving surface of the solar cell at the time of the sun altitude around the middle of the winter solstice.

The member used for the reflecting surface of the light reflector may be any member as long as it has a surface with a high reflectance. For example, a mirror, a metal plate, a metal foil, a resin, or the like may have a high reflection of metal on the surface. A layered product is suitable.

Further, for example, since the altitude of the sun is high in the middle of the south before and after the summer solstice, the amount of light incident on the light receiving surface of the solar cell is small as it is. That is, since the incident angle is small when the sun altitude is high, the reflected light of sunlight may deviate upward from the upper end of the light receiving surface of the solar cell.

Therefore, for example, a flat area and a reflection angle changing area having a reflection angle different from that of the area are formed on the reflecting surface of the light reflector, and the reflection angle changing area is elongated in the east-west direction and convex upward. When the curved reflecting means is used, the reflected light may reach the light receiving surface of the solar cell by making the reflected angle of the reflected light obtuse than that of the planar reflecting surface. Here, the reason why the reflection angle changing area is preferably a curved surface will be described. For example, a large number of plane mirrors with different angles can be used to form a pseudo curved surface. However, when the number of plane mirrors is small, the reflection of the light h greatly changes between the plane mirrors P1 and P2 as shown in FIG. Therefore, the discontinuous region D is formed on the light receiving surface of the solar cell S0 by the reflected lights k1 and k2 whose reflection angles differ greatly from the horizontal plane, and the solar cell S0 is composed of a large number of cells connected in series. In the solar cell module,
This is because the distribution of the amount of incident light occurs, the generated current is limited, and the amount of generated power decreases.

The curved surface reflecting means processes, for example, the surface of a long object, such as a pipe or rain gutter, which is laid down so as to have a high light reflectance, and arranges these so that the longitudinal direction is in the east-west direction. By removing this when unnecessary, it can be realized with a cheap and simple structure, but by configuring the light reflector in whole or in part with a shape memory material, a reflection curved surface is formed at a certain temperature or more, or it is extended. A reflective sheet body that is flat in a state and curved in a contracted state is used. It may be attached, and the other end thereof may be fixed to a base or the like on which the reflection sheet body is arranged, and the number of curved surface reflection portions may be automatically changed according to the ambient temperature. Further, the area of the curved reflection region may be changed by appropriately moving the planar reflection plate that covers the curved reflection sheet body. A bag-shaped elastic body made of synthetic rubber or the like that allows air to be taken in and out, has a large number of semi-cylindrical reflecting surfaces formed when a large amount of air is contained, and becomes flat when air is released. You may make it control the air intake and exit remotely using the reflective sheet body which consists of.

[0015]

According to the solar cell device having the above-described structure, it is possible to provide a solar cell device having a significantly simpler structure than the conventional one and having a large effect of increasing the incident amount of sunlight. In particular, since the reflecting surface of the light reflector and the light receiving surface of the solar cell are made substantially vertical, this effect can be remarkable even when the altitude of the sun is low.

Further, the reflecting surface of the light reflector is formed with a flat area and a reflection angle changing area having a large reflection angle of light from the flat area, and the reflected light in the vicinity of the light receiving surface of the solar cell is reflected by the flat area. By reflecting the light in the angle changing region, the reflected light can be appropriately incident on the light receiving surface of the solar cell even when the altitude of the sun is high.

Further, the area of the reflection angle control area is increased / decreased according to the season or the sun altitude by automatically increasing / decreasing the reflection angle change area according to the ambient temperature. It is possible to perform optimum light reception.

In particular, when a reflecting surface having a plane region and a curved region which is a reflection angle changing region is adopted, it is possible to expect an increase in the amount of incident sunlight depending on the season. Compared to a solar cell with a fixed light-receiving surface, the amount of power generated per day is more than double at around 35 ° N.

[0019]

EXAMPLE An example according to the present invention will be described in detail. The solar cell device S1 shown in FIG. 1 is installed on the roof of a building and
This is an example applied to the south solstice of the summer solstice around 35 °. Reference numeral 1 designates a light receiving surface 1a (which faces toward the south in this figure) on one main surface, and a rotary shaft 1b provided on the back side of the light receiving surface 1a substantially parallel to the light receiving surface 1a. Is a solar cell module (also called a solar cell) with a size of about 1.4 m × 4 m, and its power generation area is made up of many polycrystalline silicon (Si) cells (solar cell elements) that are arranged in parallel and are used indoors or outdoors. It is possible to supply power to the loads (various electric devices, storage batteries, various power conversion devices, other system power sources, etc.).

Here, the light receiving surface 1a of the solar cell 1 and the rotating shaft 1b have a plane area of 9 m arranged on the horizontal installation table 3.
It is arranged so as to have a substantially vertical positional relationship with the reflection surface 2a of the light reflector 2 of about 7 m. Also, the rotating shaft 1b
One end of the light reflector 2 side is rotatably supported by a horizontal installation base 3 via a bearing.
A worm wheel formed on b is connected to a rotating shaft of a motor having a worm engaged with the worm wheel, and allows the rotating shaft 1b to rotate in response to the rotation of the motor.
The rotation of the motor is controlled by a control circuit, and the rotation axis 1b is rotated so that the rotation of the motor can be rotated in either the left or right direction.
It is constructed so that it can be rotated in the range of 0 °.

The reflecting surface 2a of the light reflector 2 is made of a stainless plate and is fixed on the horizontal installation table 3. Further, in order to effectively utilize the reflected light by forming a reflecting surface as far as possible from the rotating shaft 1b, the solar cell 1 is arranged in the east-west direction.
It is 2.5 times the height of 1.4 m, that is, 3.5 m in the east and west directions about the rotating shaft 1a. In the south direction, the position where the reflected light of the sunlight reaches the upper side of the solar cell 1 (1.4 m × tan (35 °
Widening up to + 23.5 °) ≈ 2.3 m).

Further, in the vicinity of the south side of the solar cell 1 on the light reflector 2, a part of a vinyl chloride circular tube having a diameter of about 400 mm and a length of about 5 m (a center angle of about 80 °) is cut out and the surface is cut. Is Al
By arranging a number of upwardly convex curved reflectors 4 covered with foil, 6 in the summer solstice, 4 in the spring and autumn equinoxes, and 0 in the winter solstice Accordingly, the number of reflected rays of sunlight is controlled so as to reach the light receiving surface 1a of the solar cell 1 optimally (according to the altitude of the sun).

Next, the operation of this solar cell device S1 will be described. The light-receiving surface 1a of the solar cell 1 starts the timer from the position facing the east at 6 o'clock every day, causes the control circuit to control the rotation of the motor, and gradually rotates the rotation shaft 1b in the west direction with time. , South at 12 o'clock, 18
Sometimes, the position is set to face west, and at this point, the rotation shaft 1b is controlled to face to the east so as to prepare for the next day.

In addition to the above-mentioned curved reflecting means, the whole or a part of the light reflector is made of a shape memory material so that a reflecting curved surface is formed at a certain temperature or higher, or when it is extended, it becomes flat and shrinks. The area of the curved reflective region may be varied by using a reflective sheet body that is curved in a closed state or by controlling the movement of a planar reflective plate that covers the curved reflective sheet body. A bag-shaped elastic body made of synthetic rubber or the like that allows air to be taken in and out, has a large number of semi-cylindrical reflecting surfaces formed when a large amount of air is contained, and becomes flat when air is released. You may make it control the air intake and exit remotely using the reflective sheet body which consists of.

Further, the rotation of the solar cell is not limited to the fixed rotation axis as in the above embodiment, but it may be configured to rotate about the vertical axis of the reflection surface of the light reflector. Therefore, for example, the solar cell may be rotated while moving on the reflecting surface of the light reflector so as to avoid receiving reflected light from the curved reflecting area when the altitude of the sun is high. Good.

In this embodiment, the rotation of the rotating shaft is performed using a timer for about 12 hours, but the light receiving surface of the solar cell is oriented in the optimum direction at any time. In addition, for example, the control circuit may be operated based on the operation schedule set for each period to rotate the rotating shaft. Further, by intermittently driving the motor for rotating the rotating shaft, the rotating shaft is intermittently rotated, thereby reducing the power consumption of the motor and improving the tracking accuracy of the sun position. be able to.

Further, the reflection angle changing region is not limited to the above-mentioned embodiment, but can be appropriately changed and implemented within a range not departing from the gist of the present invention. Furthermore, the reflecting surface 2a of the light reflector 2 may be composed of an Al plate, a veneer plate whose surface is covered with an Al foil, a cardboard plate, a honeycomb plate, a mirror, or a stainless plate. Further, the solar cell is not limited to the above material, may be amorphous or single crystal, can be appropriately used well-known materials other than Si, the number of this solar cell is not limited to this. Absent.

Furthermore, if the rotation axis of the solar cell can be bent at the root and is made foldable, the solar cell can be fixed by tilting it on the installation surface when strong winds or when not in use. Good.

[0029]

As described above, according to the present invention, it is possible to provide a solar cell device having a great effect of increasing the amount of incident sunlight, which has a much simpler structure than the conventional one. Furthermore, unlike the conventional concentrating solar cell device, no special cooling mechanism is required, and even when tracking the sunlight, even if the tracking accuracy is rough, it does not significantly affect the amount of power generation and is highly reliable. A solar cell device can be provided.

Further, for example, by providing a reflection angle changing region for increasing the reflection angle in addition to the planar reflecting means on the south side of the light receiving surface of the solar cell, the light receiving surface of the solar cell can be exposed even when the altitude of the sun is high. It is possible to provide an excellent solar cell device in which the amount of incident light does not decrease. Furthermore, by increasing or decreasing the area of the reflection angle changing region according to the sun altitude, it is possible to provide an excellent solar cell device capable of receiving sunlight at a proper time.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment according to the present invention, (a)
Is a plan view, (b) is a front view, and (c) is a side view.

FIG. 2A is a perspective view of a circular Fresnel lens,
(B) is a perspective view of a linear Fresnel lens.

FIG. 3A is a perspective view of a circular parabolic mirror, and FIG.
FIG. 3 is a perspective view of a gutter-shaped (linear) parabolic mirror.

FIG. 4 is a schematic cross-sectional view showing how a discontinuous region of reflected light is formed on the light receiving surface of the solar cell.

[Explanation of symbols]

1 ... Solar cell 2 ... Light reflector S1 ... Solar cell device

Claims (1)

[Claims] 1. A solar cell device comprising a flat light reflector and a solar cell for receiving the reflected light of the light reflector, wherein the light receiving surface of the solar cell is the light reflector. The solar cell device is characterized in that the solar cell device is substantially perpendicular to the reflective surface and is rotatable about the vertical axis of the reflective surface of the light reflector.