JP2014063843A - Photovoltaic power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the condensing rate and homogenization of sunlight impinging on solar cells, without using a homogenizer.SOLUTION: The light reflection surface of a condensing reflector 2 is sectioned into a plurality of reflection regions 15, i.e., m×n(one of m, n is an integer of 1 or more, the other is an integer of 2 or more) reflection regions, so that the amount of incident sunlight is equal to each other. A solar cell 3 is sectioned into m×n square light-receiving regions 22 of equal area which are in one and one correspondence with respective reflection regions of the condensing reflector 2. Orientation of each reflection region 15 for each light-receiving region 22 is set individually, so that the reflection light 12 converges on the light-receiving region 22 corresponding to the reflection region 15.

Description

  The present invention relates to a solar power generation apparatus that collects sunlight into solar cells and generates power.

  2. Description of the Related Art A solar power generation device that collects sunlight into solar cells by a condensing reflector and generates electric power is known. Since the sun is circular, when the sunlight is reflected by the condensing reflector and concentrated on the solar cells, the sunlight generated in the solar cells becomes a circular spot.

  In the conventional photovoltaic power generation apparatus, the concentrating reflector only forms a circular sunlight spot concentric with the center of the solar battery cell. Therefore, if the solar spot is an inscribed circle of a square solar cell, a region where sunlight does not hit is generated at the four corners of the solar cell, and no power is generated in this region, which leads to a decrease in power generation efficiency. . In addition, when the circular spot is a circumscribed circle of a square solar battery cell, a sunlight portion that protrudes outside the solar battery cell and is not irradiated to the solar battery cell is generated, which leads to a decrease in light collection rate.

  In order to cope with this, in the solar power generation device of Patent Document 1, a homogenizer having an emission surface set to the same shape and size as the light receiving surface of the solar battery cell is disposed on the light receiving surface side of the solar cell, The sunlight reflected by the condensing reflector is made uniform by the homogenizer and then enters the solar cell (Patent Document 1 / FIG. 1).

JP 2011-243927 A

However, the photovoltaic power generation apparatus using the above homogenizer has the following problems.
(A) When sunlight is incident on the homogenizer, part of the sunlight is reflected by the incident surface, and a decrease in the amount of incident light becomes a power generation loss. As a countermeasure, it is conceivable to form an antireflection coating on the entrance surface of the homogenizer, but this increases the cost of the solar battery cell.
(B) In order to equip a solar power generation device with a homogenizer, an installation operation and a fixture are required, which leads to an increase in cost of the solar power generation device.

  The objective of this invention is providing the solar power generation device which can aim at equalizing while raising the condensing rate of the sunlight irradiated to a photovoltaic cell, without using the homogenizer leading to high cost.

  1st invention is a solar power generation device provided with a rectangular photovoltaic cell and the condensing reflector which reflects incident sunlight toward the said photovoltaic cell, Comprising: The light reflection surface of the said condensing reflector is The solar cells are divided into a plurality of m × n (where one of m and n is an integer of 1 or more and the other is an integer of 2 or more) reflective areas so that the amount of incident sunlight is equal. Each of the reflection areas of the optical reflector is divided into m × n equal-area and square light-receiving areas corresponding to 1: 1, and the light reflected by each reflection area enters the light-receiving area corresponding to the reflection area. The direction of each reflection area with respect to the light receiving area is individually set so as to gather.

  According to the first aspect of the present invention, the condensing reflector is divided so that the incident light quantity of the sunlight is equal, instead of reflecting the sunlight incident on the whole as it is on the whole solar cell. With respect to the m × n reflective areas, the direction with respect to the corresponding light receiving areas is set individually, and for each reflective area, incident sunlight is condensed on the light receiving areas of the solar cells corresponding to the reflective areas. reflect. As a result, the amount of sunlight leaked outside the solar battery cell is suppressed, the light collection rate is increased, and the area of the solar battery that is not irradiated with sunlight is reduced, so that the sunlight that enters the solar battery. Can be made uniform.

  Therefore, according to 1st invention, the solar power generation device which avoided the loss of solar energy and the increase in cost is provided, without using a homogenizer.

  According to a second invention, in the first invention, each reflection region of the light collecting reflector generates a circular sunlight spot that fits in a range between the inscribed circle and the circumscribed circle of the square in the square light receiving region. It is formed so that it may do.

  According to the second invention, the circular spot of sunlight generated in each square light receiving region of the solar battery cell falls within the range between the inscribed circle and the circumscribed circle of the square light receiving region, Minimizing the amount of sunlight leaking out of the solar cells and the non-irradiated area of sunlight at the four corners of the solar cells, and making the amount of sunlight on the solar cells uniform and improving the light collection rate Can be achieved.

The block diagram of the principal part of a solar power generation device. The figure which looked at the light reflective surface of the condensing reflector from the direction of incident light. The enlarged side view of a condensing reflector. The figure which looked at the photovoltaic cell from the facing direction of the light-receiving surface. Explanatory drawing about the diameter of the sunlight spot produced | generated in each light reception area | region of a photovoltaic cell. Explanatory drawing about the various correspondence of the reflective area | region of a condensing reflector, and the light reception area | region of a photovoltaic cell.

  With reference to FIG. 1, the structure of the principal part of the solar power generation device 1 is demonstrated. The solar power generation device 1 includes a condensing reflector 2 and a solar battery cell 3 disposed in a case 4. The side of the case 4 facing the sun 7 is a transparent wall 5, and incident light 11 from the sun 7 passes through the transparent wall 5 and enters the case 4.

  The condensing reflector 2 is supported and fixed to the inner surface of the case 4 via the stay 6. The solar cell 3 is housed in a predetermined package with output terminals, and the package is fixed at a predetermined position of the case 4 with the light receiving surface of the solar cell 3 directed toward the condensing reflector 2. Thereby, the condensing reflector 2 and the photovoltaic cell 3 are displaced integrally with the case 4 while the relative positional relationship is fixed.

  In FIG. 1, for easy understanding of the configuration of the solar power generation device 1, the solar battery cell 3 is shown with a larger dimensional ratio than the actual dimensional ratio with respect to the concentrating reflector 2. The actual dimensions of the solar battery cell 3 are, for example, a square having a light receiving surface of 0.7 cm. And the package which accommodates the photovoltaic cell 3 is about 1 cm, for example. On the other hand, the condensing reflector 2 is formed in a substantially curved surface having a light reflecting surface directed toward the solar battery cell 3 that is concave outward, and has a rectangular peripheral contour. The actual size is about 20 cm both vertically and horizontally, for example.

  The case 4 has a rectangular parallelepiped shape, and the transparent wall 5 is rectangular or square when viewed from the direction of the incident light 11. The solar power generation device 1 is a set in which a predetermined number (e.g., 8) is arranged in a line and combined, and is arranged in each predetermined place with the set as a unit. In the sunshine period, the set of the photovoltaic power generator 1 is always directed toward the sun 7 by the predetermined tracking device, and the incident light 11 enters the case 4 from a direction perpendicular to the transparent wall 5. To do.

  Incident light 11 passes through the transparent wall 5 and irradiates the condensing reflector 2. The condensing reflector 2 reflects incident light 11 and generates reflected light 12. The reflected light 12 enters the solar battery cell 3 and is converted into electric power in the solar battery cell 3.

  With reference to FIG. 2, the light reflection surface of the condensing reflector 2 is demonstrated. FIG. 2 is a view of the condensing reflector 2 as viewed from the direction of the incident light 11 in FIG. 1 when the transparent wall 5 of the case 4 is set in a direction perpendicular to the incident light 11.

  For convenience of explanation, the vertical direction and the horizontal direction in FIG. 2 are defined as the vertical direction and the horizontal direction of the condensing reflector 2. The condensing reflector 2 is disposed in the case 4 so that the lateral sides thereof are aligned in the horizontal direction. The condensing reflector 2 of the embodiment is square when viewed from the direction of the incident light 11. However, the condensing reflector 2 may be rectangular when viewed from the direction of the incident light 11.

  The light reflecting surface of the condensing reflector 2 is divided into square sections having the same dimensions of 5 × 5 when viewed from the direction of the incident light 11. The condensing reflector 2 has 5 × 5 vertical and horizontal reflection regions 15 arranged in the orientation set for each section. Since each reflecting region 15 is a square having the same size when the condensing reflector 2 is viewed from the direction of the incident light 11, the amount of light (or intensity) of the incident light 11 incident on each reflecting region 15 is equal. As a result, the amount of reflected light 12 from each reflecting region 15 is also equal.

  Each reflection area 15 has a different focal point for each reflection area 15. In order to generate the reflected light 12 toward each focal point, each reflective region 15 becomes one curved surface having a different optical axis angle and focal point for each reflective region 15. As a result, the boundary line between the reflection regions 15 adjacent in the vertical and horizontal directions is not a smooth curved surface, but becomes a ridge line as a boundary line between curved surfaces. The specific shape of the curved surface of each reflection region 15 is the shape of the side surface portion of the rotating body generated by rotating the parabola.

  The condensing reflector 2 having a different optical axis and focal point for each reflection region 15 can be easily and smoothly manufactured by using, for example, a mold technique for manufacturing a reflector for an automobile headlamp. In order to obtain a desired light distribution, the reflector of an automobile headlamp is divided into vertically long strip-like sections in the horizontal direction, and is a reflection area having a different direction for each section.

  In the embodiment of FIG. 2, the condensing reflector 2 is divided into 5 × 5 reflective areas 15 in the vertical and horizontal directions, but may be divided into vertical and horizontal reflective areas 15 other than 5 × 5 in the vertical and horizontal directions. However, one of m and n is 1 or more, and the other is an integer of 2 or more. As a result, the condensing reflector 2 is partitioned into at least 2 (= 2 × 1 or 1 × 2) or more reflection regions 15.

  In the illustrated embodiment, the vertical and horizontal dimensions are 5 × 5 for simplification of the figure, but typically the vertical and horizontal ranges are 9 × 9 to 16 × 16.

  In the embodiment of FIG. 2, the condensing reflector 2 is square when viewed from the direction of the incident light 11, but may be rectangular. Further, the shape of the reflection region 15 viewed from the direction of the incident light 11 may be a rectangle instead of a square. However, regardless of whether the shape of the reflection region 15 viewed from the direction of the incident light 11 is square or rectangular, the reflection regions 15 viewed from the direction of the incident light 11 are equal in diameter and equal to each other. Thereby, the incident light quantity of the incident light 11 in each reflective area | region 15 is made mutually equal.

  With reference to FIG. 3, the structure of the condensing reflector 2 is further demonstrated. In FIG. 3, for convenience of explanation, the reflection area 15 is arranged in the order of reflection areas 15-1, 15-2,. 5 is attached. The projection surface 17 is a virtual surface for convenience of explanation, and is disposed at a right angle to the incident light 11 on the back side of the reflection region 15.

  The projection lengths of the reflection regions 15-1 to 15-5 on the projection surface 17 are all equal to L. Thereby, the light quantity of the incident light 11 irradiated to the reflective areas 15-1 to 15-5 becomes equal to each other. Since the reflective areas 15-1 to 15-5 form separate curved surfaces, the boundary points between the two reflective areas 15 adjacent in the vertical direction are convex as shown in FIG.

  The solar battery cell 3 will be described with reference to FIG. FIG. 4 is a view of the solar battery cell 3 as seen from the front direction of its light receiving surface.

  For convenience of explanation, the vertical direction and the horizontal direction in FIG. 4 are defined as the vertical direction and the horizontal direction of the solar battery cell 3. Usually, the lateral side of the solar battery cell 3 is parallel to the lateral side of the condensing reflector 2. However, if the optical axis of the reflected light 12 from each reflecting region 15 of the condensing reflector 2 is set to have a predetermined rotation angle around the optical axis of the reflected light 12 at the center of the condensing reflector 2, the sun The lateral side of the battery cell 3 is not parallel to the lateral side of the condensing reflector 2 but has an inclination angle corresponding to the predetermined rotation angle around the optical axis.

  The solar battery cell 3 of the embodiment has a square shape. The solar battery cell 3 may be rectangular. However, a light receiving area 22 described later is defined as a square in order to generate a suitable circular sunlight spot 23 in the light receiving area 22 regardless of whether the solar battery cell 3 is square or rectangular.

  The demarcation line 21 does not exist on the solar cell 3 itself, and is a virtual line for convenience shown in FIG. 4 in order to describe the light receiving region 22 on the solar cell 3.

  The light receiving surface of the solar battery cell 3 is divided into square light receiving regions 22 having an equal area of 5 × 5 divided into five equal parts in the vertical and horizontal directions by the dividing line 21 in accordance with the number of the reflective regions 15 of the condensing reflector 2. . The reflection region 15 of the condensing reflector 2 and the light receiving region 22 of the solar battery cell 3 are associated with 1: 1. When the condensing reflector 2 is divided into the m × n reflection region 15, the solar battery cell 3 is also divided into the m × n light receiving region 22.

  In each light receiving region 22 of the solar battery cell 3, a circular sunlight spot 23 is generated by the reflected light 12 from the corresponding reflecting region 15 of the condensing reflector 2. If only one solar spot of the reflected light 12 from the condensing reflector 2 is formed in the entire solar cell 3, the four corners of the solar cell 3 are not exposed to the light of the solar spot, The power generation efficiency of the battery cell 3 decreases. Further, in order to avoid this, when the diameter of the solar spot is increased so that the solar spot hits the entire solar battery cell 3, a part of the solar spot protrudes from the solar battery cell 3, The light quantity (energy) of sunlight in the solar battery cell 3 is reduced.

  On the other hand, in the solar power generation device 1, a sunlight spot 23 is generated at each corner of the solar battery cell 3 in each light receiving region 22 belonging to the corner. Therefore, it is suppressed that sunlight leaks out of the solar battery cell 3, and the area which does not receive sunlight in the solar battery cell 3 decreases. As a result, the sunlight in the solar battery cell 3 is made uniform, the light collection rate to the solar battery cell 3 is increased, and the power generation efficiency of the solar power generation device 1 can be increased.

  With reference to FIG. 5, the relationship between the light receiving region 22 and the sunlight spot 23 generated in the light receiving region 22 will be described. The inscribed circle 23a and the circumscribed circle 23b are an inscribed circle and a circumscribed circle of the square light receiving region 22, respectively. In each light receiving region 22 of the solar battery cell 3, a sunlight spot 23 is generated by the reflected light 12 from the corresponding reflecting region 15 of the condensing reflector 2. The generated sunlight spot 23 is concentric with the inscribed circle 23a and the circumscribed circle 23b, and the circumference falls within the range between the inscribed circle 23a and the circumscribed circle 23b. That is, the sunlight spot 23 becomes an inscribed circle 23a when it is minimum, and becomes a circumscribed circle 23b when it is maximum.

  Note that the sunlight spot 23 is in the range between the inscribed circle 23a and the circumscribed circle 23b when the reflection region 15 of the condensing reflector 2 is square or rectangular when viewed from the direction of the incident light 11. Even so, the optical axis and focus of the reflected light 12 from each reflective region 15 are set as such. Even if the reflection region 15 of the condensing reflector 2 is rectangular when viewed from the direction of the incident light 11, the optical axis of the reflected light 12 from the reflection region 15 passes through the center of the light receiving region 22 of the solar battery cell 3. By setting and adjusting the focal point, it is possible to generate a sunlight spot 23 having a size range from the inscribed circle 23a to the circumscribed circle 23b in the light receiving region 22.

  In the sunlight spot 23 of the inscribed circle 23 a, areas where the sunlight spot 23 does not hit the four corners of the light receiving area 22 are generated. As the sunlight spot 23 expands from the inscribed circle 23a toward the circumscribed circle 23b, the areas of the four corners where the sunlight spot 23 is not irradiated are reduced and the sunlight spot 23 that protrudes to the adjacent light receiving region 22 is reduced. The area of the portion increases. And when the sunlight spot 23 turns into the circumscribed circle 23b, the sunlight spot 23 is irradiated to the entire light receiving area 22, but the area of the portion of the sunlight spot 23 that protrudes from the light receiving area 22 is maximized.

  When the sunlight spots 23 generated in the respective light receiving areas 22 are set to have the same diameter, the light receiving areas 22 adjacent to each other in the vertical and horizontal directions are irradiated to the protruding portions of the sunlight spots 23 from the adjacent light receiving areas 22, This portion becomes an overlapping irradiation portion of the sunlight spot 23, and the luminous intensity increases. However, since the area of the overlapping irradiation portion is limited as viewed from the entire area of the solar battery cell 3, the uniformity of the amount of sunlight in the solar battery cell 3 is ensured.

  With reference to FIG. 6, a typical correspondence relationship between the reflection region 15 of the condensing reflector 2 that is the reflection source of the reflected light 12 and the light receiving region 22 of the solar cell 3 that is the reflection destination of the reflection light 12 will be described. The correspondence relationship is not limited to one but various.

  In order to explain the correspondence between the reflection source and the reflection destination of the reflected light 12, the vertical and horizontal positions of the reflection region 15 of the condensing reflector 2 and the light receiving region 22 of the solar battery cell 3 are copied in accordance with the definition of the element position of the matrix. , (Row number, column number). According to this notation, in the condensing reflector 2 and the solar battery cell 3, the positions of the reflection area 15 and the light receiving area 22 in the upper left corner are (1, 1), and the positions of the reflection area 15 and the light receiving area 22 in the upper right corner. Is (1, 5), the positions of the reflection area 15 and the light receiving area 22 in the lower left corner are (5, 1), and the positions of the reflection area 15 and the light receiving area 22 in the lower right corner are (5, 5). .

  FIG. 6A is an example in which the vertical and horizontal positions of the reflection region 15 and the light reception region 22 are the same in the relationship between the reflection source and the reflection destination of the reflected light 12. The reflection destination of the reflected light 12 from the reflection region 15 of (1, 1), (1, 2),..., (5, 4), (5, 5) of the condenser reflector 2 is (row number, The light receiving regions 22 of (1, 1), (1, 2),..., (5, 4), (5, 5) of the solar cells 3 having the same column number). That is, the (u, v) reflection region 15 of the condensing reflector 2 and the (u, v) light receiving region 22 of the solar battery cell 3 correspond to 1: 1.

  In FIG. 6B, the vertical and horizontal positions of the reflection area 15 and the vertical and horizontal positions of the light receiving area 22 in the relationship between the reflection source and the reflection destination of the reflected light 12 are obtained by exchanging the row numbers and the column numbers with each other. This is an example. The reflection destination of the reflected light 12 from the reflection region 15 of (1, 1), (1, 2),..., (5, 4), (5, 5) of the condensing reflector 2 is (1, 1 ), (2, 1),..., (4, 5), (5, 5). That is, the (u, v) reflection region 15 of the condensing reflector 2 and the (v, u) light receiving region 22 of the solar battery cell 3 correspond to 1: 1.

  FIG. 6C is an example in which the vertical and horizontal positions of the reflection region 15 and the vertical and horizontal positions of the light receiving region 22 in the relationship between the reflection source and the reflection destination of the reflected light 12 have a point-symmetric relationship. The reflection destination of the reflected light 12 from the reflection region 15 of (1, 1), (1, 2),..., (5, 4), (5, 5) of the condensing reflector 2 is (3, 3 ) (5, 5), (5, 4),..., (1, 2), (1, 1) of the photovoltaic cells 3 that are in a point-symmetrical relationship with respect to (). That is, the (u, v) reflection region 15 of the condensing reflector 2 and the (6-u, 6-v) light receiving region 22 of the solar battery cell 3 correspond to 1: 1.

  In the solar power generation device 1, the m × n reflection areas 15 of the condensing reflector 2 and the m × n light reception areas 22 of the solar battery cells 3 are associated with each other in a 1: 1 ratio, and each of the light reception areas 22 has a sun. A light spot 23 is formed. Therefore, although the solar power generation device 1 is not equipped with a homogenizer, the solar cell 3 is not limited to a square, and even if the solar cell 3 is rectangular, the amount of sunlight on the light receiving surface of the solar cell 3 ( Energy amount) can be made uniform.

  Although the present invention has been described with respect to the embodiments, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the invention.

  For example, in FIG. 5, a sunlight spot 23 having the same diameter is formed in each light receiving region 22 of the solar battery cell 3, but the size of the sunlight spot 23 is different for each light receiving region 22. Also good. For example, the sunlight spot 23 in the light receiving region 22 around the solar battery cell 3 is the smallest inscribed circle 23a, and the sunlight spot 23 in the light receiving region 22 inside is larger than the smallest inscribed circle 23a. You can also Thereby, it is possible to make the sunlight on the solar battery cell 3 uniform while setting the area of the solar light spot 23 protruding outside the solar battery cell 3 to zero.

  Various correspondences between the reflection region 15 of the condensing reflector 2 that is the reflection source of the reflected light 12 and the light receiving region 22 of the solar cell 3 that is the reflection destination of the reflection light 12 are shown in FIGS. In addition to the three examples shown in c), the reflection destination of the reflected light 12 having the reflection region 15 in the peripheral portion of the condensing reflector 2 as a reflection source is the light receiving region 22 in the central portion of the solar battery cell 3, and the condensing reflector The reflection destination of the reflected light 12 having the reflection area 15 at the center of 2 as the reflection source may be the light receiving area 22 in the peripheral portion of the solar battery cell 3.

DESCRIPTION OF SYMBOLS 1 ... Solar power generation device, 2 ... Condensing reflector, 3 ... Solar cell, 7 ... Sun, 11 ... Incident light, 12 ... Reflected light, 15 ... Reflection Area, 22 ... light receiving area, 23 ... sunlight spot, 23a ... inscribed circle, 23b ... circumscribed circle.

Claims (2)

A rectangular solar cell;
A solar power generation apparatus comprising a condensing reflector that reflects incident sunlight toward the solar cell,
The light reflecting surface of the condensing reflector is divided into a plurality of m × n reflecting areas (one of m and n is an integer of 1 or more and the other is an integer of 2 or more) so that the amount of incident sunlight is equal. ,
The solar battery cell is divided into m × n equal-area and square light-receiving areas corresponding to the respective reflecting areas of the condensing reflector in a 1: 1 ratio.
The photovoltaic power generation apparatus, wherein the direction of each reflection region with respect to the light receiving region is individually set so that the light reflected by each reflection region gathers in the light receiving region corresponding to the reflection region. In the solar power generation device according to claim 1,
Each reflection region of the condensing reflector is formed so as to generate a circular sunlight spot that falls within a range between the inscribed circle and the circumscribed circle of the square in the square light receiving region. A solar power generation device.

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