JP2013030553A - Collector, and solar cell with collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a collector with high light collection efficiency and lower processing cost.SOLUTION: A collector comprises: a first light guide body 1 having a first incident plane receiving light from the outside and a first emission plane emitting the incident light; and a second light guide body 2 having a second incident plane disposed to be faced to the first emission plane side of the first light guide body 1 and receiving the light from the first light guide body 1 and a second emission plane emitting the incident light. In the first emission plane of the first light guide body 1, a row of a plurality of first triangle prisms 13 extending in one direction and a first flat part 14 are alternately arranged. In the second incident plane of the second light guide body, a second triangle prism 23 having the same width as that of the first flat part and extending in the same direction as an extending direction of the first prism 13 is formed at a position facing the first flat part. A second flat part 24 adjacent to the second prism 23 is formed in the second incident plane, and the light is taken from the second emission plane right under the second prism 23.

Description

  The present invention relates to a concentrator and a solar cell using the concentrator.

A conventional concentrating solar cell is provided with a large-scale solar tracking function device for a photoelectric conversion element using a compound-based material, and has a method of collecting light 100 times or more to obtain high conversion efficiency. The method has become mainstream.
On the other hand, a system for generating power without significantly reducing the conversion efficiency has been proposed without considering a solar tracking device or the like and taking into consideration changes in the solar altitude of the day and changes in the solar altitude due to the season.
For example, as shown in Patent Document 1, a concentrating solar cell has been devised that uses a wedge-shaped transparent body as a method that does not use a lens and aims to reduce the amount of solar cell material used (Patent Document). 1, see FIG. In order to reduce the size and weight, it has been proposed to form a photoelectric conversion element in a linear form in combination with a condensing lens (see, for example, Patent Document 2 and FIG. 15).

Japanese Patent Laid-Open No. 06-275859 JP 2008-83641 A

However, in the method of Patent Document 1, light is condensed by making the oblique side of a right triangle with the acute angle portion of the transparent light guide defined as 21 ° a light-receiving surface and bringing a photoelectric conversion element into close contact with the short side. In the case of a monocrystalline or polycrystalline silicon type solar cell, one side of the solar cell is processed into a 160 mm square shape. Therefore, when this is applied in four equal parts, the transparent light guide has a right angle of 104 mm × 40 mm. A triangular prism with a sectional area of 2080 mm @ 2 is required.
If further subdivided, the cross-sectional area of the transparent light guide to be used can be reduced, but there is a concern about the risk of performance deterioration and an increase in processing cost due to the process of dividing the photoelectric conversion element.

  Further, in the method of Patent Document 2, it is assumed that the size of the photoelectric conversion element is 0.2 mm to 5 mm, but the transparent light guide is obtained by dividing one transparent rod into six on the photoelectric conversion element. Therefore, a processing method with a high degree of difficulty is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a concentrator that has high condensing efficiency and can reduce the cost of processing.

  The collector according to the present invention includes a first light guide having a first incident surface on which light from the outside is incident, and a first emission surface that emits the incident light, and the first light guide. A second light guide disposed opposite to the first light exit surface and having a second incident surface for receiving light from the first light guide and a second output surface for emitting the incident light. A plurality of triangular first prism rows extending in one direction and first flat portions are alternately formed on the first light exit surface of the first light guide. On the second incident surface of the second light guide, a triangular second prism having the same width as the first flat portion and extending in the same direction as the extending direction of the first prism is formed on the first flat surface. The second incident surface is formed with a second flat portion adjacent to the second prism, and a second emission surface directly below the second prism. Ri and wherein the extracting light.

  Since the concentrator according to the present invention is configured to use two light guides having triangular prisms as described above, it is easy to assemble, thereby reducing the processing cost. In addition, the light collection efficiency can be improved.

It is a perspective view of the solar cell provided with the concentrator concerning Embodiment 1 of this invention. It is sectional drawing of the solar cell provided with the concentrator concerning Embodiment 1 of this invention. It is edge part sectional drawing of the solar cell provided with the collector concerning Embodiment 1 of this invention. It is sectional drawing for prescribing | regulating the dimension of the solar cell provided with the concentrator concerning Embodiment 1 of this invention. It is sectional drawing of the solar cell provided with the concentrator concerning Embodiment 1 of this invention. It is sectional drawing of the solar cell provided with the collector concerning Embodiment 3 of this invention. It is a correlation diagram of the ratio of the light which can be utilized with the sunlight incident angle of the solar cell provided with the collector | collector concerning Embodiment 3 of this invention at the time of the south. It is sectional drawing of the solar cell provided with the collector concerning Embodiment 4 of this invention. It is sectional drawing of the solar cell provided with the collector concerning Embodiment 5 of this invention. It is a correlation diagram of the ratio of the light which can be utilized, and the sunlight incident angle at the time of the south middle of the solar cell provided with the collector concerning Embodiment 5 of this invention. It is sectional drawing of the solar cell provided with the collector concerning Embodiment 6 of this invention. It is a perspective view of the solar cell provided with the collector concerning Embodiment 6 of this invention. It is a perspective view of the solar cell provided with the collector concerning Embodiment 7 of this invention.

Embodiment 1 FIG.
First, the overall configuration of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a solar cell provided with a collector according to Embodiment 1 of the present invention. Except as otherwise noted, the overall configuration is common to all the embodiments. Moreover, what attached | subjected the same code | symbol is the same or it corresponds, This is common in the whole text of a specification.

  As shown in FIG. 1, the solar cell provided with the concentrator according to this embodiment includes a first transparent light guide 1 and a first transparent light guide 1 in which a plurality of triangular prisms 13 for adjusting the inclination of light are arranged. The triangular prism 23 larger than the triangular prism 13 of the transparent light guide is periodically arranged, and the second transparent light guide 2 is arranged in close contact with the base of the triangular prism 23 of the second transparent light guide 2. The photoelectric conversion element 3 is configured.

  As the first light guide 1, glass or an acrylic resin coated with an inorganic material to impart flame retardancy is used. In the case of a silicon type solar cell module, the solar cell is often covered with a glass plate, and a triangular prism may be directly formed on such a glass plate, or a transparent resin sheet formed with a triangular prism. May be pasted.

  Further, glass can be used as the material of the second light guide 2. In many cases, silicon type solar cell modules are filled with ethylene vinyl acetate (EVA) between the outermost glass plate and the photoelectric conversion element, but this resin is given a triangular prism shape by injection molding. The second transparent light guide 2 may be used. Further, the material of the second light guide 2 may be anything as long as it is a highly transparent resin, and acrylic resin, polycarbonate, or the like can be used.

  Next, the light collecting action will be described with reference to FIG. FIG. 2 is a cross-sectional view of a solar cell provided with the collector of the present embodiment. In the figure, 3a, 3b and 3c are adjacent photoelectric conversion elements. The arrow indicated by reference numeral 4a is incident on the flat portion 14 without the triangular prism array of the first light guide 1, and after incident on the triangular prism 23 of the second light guide, is totally reflected by the prism surface and photoelectrically reflected. This is a locus of light reaching the conversion element 3b. The arrow indicated by reference numeral 4 b passes through the triangular prism 13 of the first light guide 1, enters the triangular prism 23 of the second light guide 2, and then totally reflects off the prism surface to the photoelectric conversion element 3 b. It is the trajectory of the reaching light. Similarly, arrows indicated by reference numerals 4c and 4d pass through the triangular prism 13 of the first light guide 1, enter the triangular prism 23 of the second light guide 2, and then the second light guide. 2 is a trajectory of light reaching the photoelectric conversion element 3c after propagating through the two flat portions 24 by total reflection. Similarly, an arrow indicated by reference numeral 4e passes through the triangular prism 13 of the first light guide 1, enters the triangular prism 23 of the second light guide 2, and then reaches the photoelectric conversion element 3b. It is a trajectory. Similarly to 4a, 4f is incident on the flat portion 14 without the triangular prism row of the first light guide 1, and after entering the triangular prism 23 of the second light guide, is totally reflected on the prism surface and is subjected to photoelectric conversion element 3a. Is the trajectory of light reaching The difference between 4f and 4a is symmetric with respect to the vertical line in the figure. The light between 4a and 4b is the same as 4a. The light between 4b and 4c is the same as 4b. The light between 4c and 4d is the same as 4c and 4d. The light between 4d and 4e is 4e. Similarly, light between 4e and 4f draws the same locus as 4f.

  Thus, it is possible to condense light by periodically forming triangular prism rows in the first light guide and periodically forming triangular prisms in the second light guide. Become.

  In the above description, only the light traveling in the right direction in the figure with respect to the light incident on the triangular prism row of the first light guide 1 has been described. Is right / left symmetrical, it is only necessary to convert the light traveling in the right direction to the left as it is, and it is understood that all the light reaches the photoelectric conversion element by the same principle.

  Most of the light that enters perpendicularly to the first light guide 1 reaches the photoelectric conversion element 3, and the amount of collected light is about 87% of the received light amount. What does not become 100% is reflected light generated at the interface when entering the first light guide 1, reflected light at the interface when exiting from the first light guide 1, and the second light guide This is because there is reflected light at the interface when entering 2 and reflected light generated at the interface when entering the photoelectric conversion element.

  FIG. 3 is a cross-sectional view of an end portion of a light guide body of a solar cell provided with a condenser. At the end of the light collector, there is a specular reflector 5 formed of a metal such as silver or aluminum as a first reflector, or a resin coated with a metal. The specular reflector 5 has a surface provided with an inclination angle so that the light transmitted through the first light guide 1 is reflected substantially in the horizontal direction.

In the drawing, arrows indicated by reference numerals 4i, 4h, and 4g all indicate the trajectory of light that is reflected by the specular reflector 5 and reaches the photoelectric conversion element. An arrow line 4 i is light that directly reaches the photoelectric conversion element 3 e after passing through the inclined surface of the second light guide 2. An arrow line 4h is light that totally reflects inside the flat portion 24 of the second light guide after passing through the inclined surface of the second light guide 2, and reaches the photoelectric conversion element 3d. An arrow line 4g is light that reaches the photoelectric conversion element 3e after being transmitted through the inclined surface of the second light guide 2 and totally reflected by the triangular prism.
Thus, most of the light can be collected by arranging the specular reflector 5 at the end.

Furthermore, the specific example of the dimension of this collector is demonstrated using FIG.
The thickness of the first light guide ₁ is d ₁ , the height of the triangular prism 13 of the first light guide 1 is d ₂ , the height of the triangular prism 23 of the second light guide is d ₃ , the second light guide the height of the flat portion 24 and d _4. Further, the length of the first triangular prism row and the length of the flat portion 24 of the second light guide are substantially equal to l _1, and the apex angle α ₁ of the first triangular prism and the apex angle α of the second triangular prism are set. ₂ . The inclination angle of the specular reflector 5 is θ. The width of the photoelectric conversion element 5 is a.

As a specific example 1, when the photoelectric conversion element is polycrystalline silicon or single crystal silicon, the photoelectric conversion element 5 is cut out from a 20-inch wafer. A = 40 mm, d ₁ = 3 mm, d ₂ = 0.3 mm, d ₃ = 34.6 mm, d4 = 3 mm, l ₁ = 60 mm, α ₁ = 60 ° α ₂ = 60 ° and β = 70 °.

As a specific example 2, the width of the photoelectric conversion element 5 can be arbitrarily selected for a thin film semiconductor such as CdTe that can be formed by screen printing or amorphous silicon that can be formed by a photolithography technique. As the size that can reduce the thickness of the entire solar cell module, a = 1 mm, d ₁ = 3 mm, d ₂ = 0.3 mm, d ₃ = 0.87 mm, d ₄ = 0.4 mm, l ₁ = 1.5 mm.
Note that the angles α ₁ , α ₂ , and β may be finely adjusted within a range of ± 5 °.

  As described above, the light collector according to the present embodiment uses two light guides each having a triangular prism of a different arrangement. Therefore, although it looks like a complicated shape at first glance, there are only two members, and assembly is easy. Further, the technology for forming a triangular prism on a transparent plate is a technology applied to a backlight of a liquid crystal display, and has been established as a processing technology. Therefore, the processing cost can be reduced in manufacturing the concentrator.

  Further, the light incident on the triangular prism row of the first light guide 1 is bent leftward and proceeds to the second light guide 2. And after repeating reflection in the 2nd light guide 2, all the light reaches | attains the photoelectric conversion element 3. FIG. The light incident on the flat portion 14 of the first light guide is incident on the triangular prism 23 of the second light guide, and then totally reflected by the prism surface and reaches the photoelectric conversion element 3. Therefore, the light collection efficiency can be increased.

Embodiment 2. FIG.
In the first embodiment, the sunlight 4e is incident on the second light guide 2 from the triangular prism surface, but is incident from the flat portion 24 of the second light guide 2 and enters the photoelectric conversion element 3. It can also be made incident. Hereinafter, this embodiment will be described.

と表される。
ｄ_４＝１６、θ＝３５．５°とした場合、l₂＝１１．４ｍｍとなる。
したがって、集光倍率は、

より、２．８倍となる。 FIG. 5 is a cross-sectional view of a solar cell provided with the collector according to the second embodiment.
In the present embodiment, the flat portion can be lengthened by l ₂ as compared with the first embodiment, and the condensing magnification is increased. l ₂ depends on the incident angle of light, and if the angle θ between the light transmitted through the flat portion and the flat portion is

It is expressed.
When d ₄ = 16 and θ = 35.5 °, l ₂ = 11.4 mm.
Therefore, the concentration factor is

Therefore, it becomes 2.8 times.

  As described above, by adjusting the thickness of the second light guide 2, the light incident on the flat portion 24 of the second light guide 2 can be made incident on the photoelectric conversion element 3, and the light is condensed. The magnification can be increased.

Embodiment 3 FIG.
In the third embodiment, in addition to the configuration of the first embodiment, an example in which a reflection sheet 6 that is a second reflector is provided on the bottom surface of the second light guide 2 will be described. FIG. 6 is a cross-sectional view of a solar cell provided with a collector according to the present embodiment. In FIG. 6, the reflective sheet 5 that is specularly reflected is disposed on the bottom surface of the second light guide 2. The arrow line indicated by reference numeral 4 j is a locus of light incident at an angle of about 10 ° with respect to the outermost surface of the first light guide 1. As illustrated, when sunlight strikes the right inclined surface of the triangular prism row of the first light guide 1, the light is incident on the flat portion of the second light guide 2.

  In the case of Embodiments 1 and 2 without the reflection sheet, the light may be transmitted as it is. However, since the reflection sheet 6 is present, the direction of travel by the triangular prism is deflected, and then the photoelectric under the next triangular prism is obtained. It is absorbed by the conversion element 3a. Thus, if the reflective sheet 6 is placed, the light collecting effect can be maintained even if the sun is tilted to some extent.

  The solar cell provided with the light collector according to the present embodiment is preferably arranged in a direction perpendicular to the paper surface from east to west and from side to side in the left and right direction of the paper surface. It is good to arrange so that light may enter. Ideally, it is arranged so that light is incident vertically on the light guide 1 during the spring and autumn days of the spring and autumn days, and at an angle of incidence of ± 23.4 ° during the summer solstice and winter solstice. . About the case where the reflector of the dimension shown in Embodiment 2 is provided with the reflection sheet 6, the amount of light incident on the outermost surface of the first light guide 1 is 1, and the sun in the north-south direction The ratio of light that can be used with respect to the tilt is shown in FIG. In this example, it can be seen that there is about 40% efficiency even at an incident angle of 23.4 °.

  With the configuration described above, light can be collected as described in the first and second embodiments with respect to the east-west inclination of the incident light. In addition, for the north-south direction of the sun, light can be collected using a reflective sheet.

  In the present embodiment, the specular reflection sheet is used. However, the effect of improving the light utilization efficiency can be expected even with a reflection sheet that performs diffuse reflection. In addition, sandwiching the photoelectric conversion element 3 between the light guide and the sheet in this way can also be expected to prevent deterioration such as surface oxidation without causing the photoelectric conversion element 3 to directly contact air.

Embodiment 4 FIG.
In the fourth embodiment, an example in which the first light guide 1 is improved with respect to the configuration of the first embodiment will be described. FIG. 8 is a cross-sectional view of a solar cell provided with a collector according to this embodiment.

  In the present embodiment, the flat portion 14 of the first light guide 1 and the apex portion of the triangular prism 23 of the second light guide 2 are connected by a transparent prism member 7. Thereby, the light 4a incident from the flat portion 14 of the first light guide 1 has no loss when passing through the first light guide 1, and no loss when entering the second light guide 2. The light can be incident on the photoelectric conversion element 3b without reducing the light intensity.

  Further, if the size of the transparent prism member 7 is adjusted so that the light 4b transmitted through the triangular prism row of the first light guide 1 hits the triangular prism 23 of the second light guide 2, The corresponding amount of light can also be incident on the photoelectric conversion element 3b.

  Furthermore, the first light guide 1 and the second light guide 2 are connected by connecting the flat portion of the first light guide 1 and the apex of the triangular prism of the second light guide 2 with the prism member 7. There is also a function of fixing the mutual position between the first light guide body 1 and the second light guide body 2 due to secular change.

Embodiment 5 FIG.
In the fifth embodiment, an example in which a part of the second light guide 2 is omitted from the configuration of the first embodiment will be described. FIG. 9 is a cross-sectional view of a solar cell provided with a collector according to Embodiment 5 of the present invention.

  The flat part of the second light guide 2 is eliminated, and the triangular prisms 2a, 2b, and 3c are individually adhered and fixed as the second light guide on the photoelectric conversion elements 3a, 3b, and 3c. In order to align the first light guide 1 and the second light guides 2a, 2b, and 2c, the reflection sheet 5 is fixed to a hard pedestal or the like, or a highly reflective metal plate or the like is used.

  In FIG. 10, the ratio of the light which can be utilized with respect to the inclination of the sun of north-south direction is shown. The ratio of the amount of light reaching the photoelectric conversion element 3 is shown with the amount of light incident on the outermost surface of the first light guide 1 being 1. A solid line indicates a ratio of light according to the configuration of the third embodiment, and a broken line indicates a ratio at which light according to the present embodiment can be used. Although the proportion of light that can be used at a light incident angle of 0 ° is low, the proportion of light that can be used can be made higher than that in Embodiment 3 at an incident angle of 2 ° or more.

Embodiment 6 FIG.
FIG. 11 shows a cross-sectional view of a solar cell provided with the collector according to the sixth embodiment, and FIG. 12 shows an overview of the whole. In FIG. 11, the third light guide 30 has a plurality of triangular prisms 33 arranged on both sides around a flat portion 34. Further, the fourth light guide 40 has the triangular prism 20 formed at the center and the flat portions 44 formed on both sides thereof. Further, the third reflector 35 having a mirror surface is disposed at both ends of the fourth light guide 40. A third reflector 35 is connected between the edges of the third light guide and the fourth light guide. Using this shape as a basic shape, it can be repeatedly arranged as shown in FIG. In addition, this shape can also be considered that the end part shape of Embodiment 1 is arrange | positioned line-symmetrically with respect to the perpendicular line.

つまり、鏡面の第３の反射体３５により反射された光も中央の三角プリズムに集めることができるので、集光倍率を４．６倍と高い倍率にできる。 Here, when the condensing magnification of this embodiment is calculated, in the formula (1) described in Embodiment 2, when d ₄ = 16 and θ = 35.5 °, l ₂ = 11.4 mm. ,
It can be calculated from the following calculation.

That is, since the light reflected by the mirror-like third reflector 35 can also be collected on the central triangular prism, the light collection magnification can be increased to 4.6 times.

Embodiment 7 FIG.
FIG. 13 shows an overview of the entire solar cell in which the collectors according to the seventh embodiment are arranged vertically and horizontally. The solar cell provided with the concentrator shown in FIG. 11 according to the sixth embodiment described above has a rotationally symmetric shape that is rotated about an axis passing through the apex of the triangular prism, according to the seventh embodiment. It is a solar cell provided with a condenser. The shape of the fifth light guide is composed of a plurality of triangular prisms arranged concentrically with a disk-shaped fifth flat portion at the center. The sixth light guide has a conical shape at the center and a flat disk shape on the outer periphery. The outer periphery of the second light guide 2 is surrounded by a mirror-like fourth reflector, and the fourth reflector is connected between the edges of the fifth light guide and the sixth light guide. The cross section of the condenser is the same as in FIG.

２１倍と高い倍率にできる。 Concentration magnification from the following rough calculation

The magnification can be as high as 21 times.

  It should be understood that the above-described embodiment is illustrative in all respects and not restrictive. The scope of the present invention is shown not by the scope of the above-described embodiment but by the scope of the claims, and includes all modifications within the meaning and scope equivalent to the scope of the claims.

  DESCRIPTION OF SYMBOLS 1 1st light guide, 2nd 2nd light guide, 3 photoelectric conversion element, 4 light locus, 5 specular reflector, 6 reflective sheet, 7 columnar member, 11 1st entrance plane, 12 1st Outgoing surface, 13 1st prism, 14 1st flat part, 21 2nd entrance surface, 22 2nd outgoing surface, 23 2nd prism, 24 2nd flat part, 30 3rd light guide 31 Third entrance surface, 32 3rd exit surface, 33 3rd prism, 34 3rd flat part, 35 3rd reflector, 40 4th light guide, 41 4th entrance surface, 42 4th emission surface, 43 4th prism, 44 4th flat part.

Claims (10)

A first light guide having a first incident surface on which light from the outside is incident and a first emission surface that emits the incident light;
A second incident surface that is disposed to face the first light exit surface side of the first light guide and receives light from the first light guide, and a second light exit surface that emits the incident light A second light guide having
A plurality of triangular first prism rows extending in one direction and first flat portions are alternately formed on the first light exit surface of the first light guide,
The second incident surface of the second light guide has a triangular second prism having the same width as the first flat portion and extending in the same direction as the extending direction of the first prism. 1 is formed at a position facing the flat portion of 1,
Furthermore, a second flat part is formed on the second incident surface adjacent to the second prism,
A light collector for extracting light from a second emission surface directly below the second prism.   A first reflector that is an end of the first light guide and the second light guide and reflects light between the first light guide and the second light guide. The concentrator according to claim 1.   2. The concentrator according to claim 1, wherein the second exit surface excluding the region immediately below the second prism is covered with a second reflector.   2. The light collecting device according to claim 1, further comprising a columnar member at a vertex portion of the triangular second prism, wherein the first light guide and the second prism are coupled via the columnar member. vessel.   The concentrator according to claim 1, wherein a second reflector is installed instead of the second flat portion constituting the second light guide. Concentrator.   A solar cell comprising the concentrator according to any one of claims 1 to 5, wherein a photoelectric conversion element is disposed on a second emission surface immediately below the second prism. A third light guide having a third incident surface on which light from the outside is incident and a third emission surface that emits the incident light;
A fourth incident surface that is disposed opposite to the third light exit surface side of the third light guide and receives light from the third light guide and a fourth light exit surface that emits the incident light A fourth light guide having
A third reflector for connecting the edges of the third light guide and the fourth light guide,
A row of a plurality of triangular third prisms extending in one direction on both sides across the third flat portion is formed on the third emission surface of the third light guide,
The fourth light incident surface of the fourth light guide has a triangular fourth prism having the same width as the third flat portion and extending in the same direction as the extending direction of the third prism. 3 is formed at a position opposite to the flat portion 3, and a fourth flat portion is formed on the fourth incident surface adjacent to the fourth prism,
A light collector for extracting light from a fourth emission surface directly below the fourth prism.   A solar cell comprising the concentrator according to claim 7, wherein a photoelectric conversion element is arranged on a fourth emission surface directly below the fourth prism. A fifth light guide having a fifth incident surface on which light from the outside is incident and a fifth emission surface that emits the incident light;
A sixth incident surface that is disposed to face the fifth light exit surface side of the fifth light guide and receives light from the fifth light guide and a sixth light exit surface that emits the incident light A sixth light guide having
A fourth reflector connecting the edges of the fifth light guide and the sixth light guide,
On the fifth light exit surface of the fifth light guide, a plurality of triangular third prism rows are formed concentrically around the circular fifth flat portion.
On the sixth entrance surface of the sixth light guide, a sixth prism having a triangular cross section having the same width as the fifth flat portion is formed at a position facing the fifth flat portion, Furthermore, a sixth flat portion is formed around the sixth prism on the sixth incident surface,
A light collector for extracting light from a sixth emission surface directly below the sixth prism.   A solar cell comprising the concentrator according to claim 9, wherein a photoelectric conversion element is arranged on a sixth emission surface directly below the sixth prism.

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