JP2001313411A - Solar cell module transmitting natural light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module, where the greater part of light absorbed for contributing to power generation is a light which reach directly from the sun, and transmitted light is natural light in the solar cell module which has optical transmittivity. SOLUTION: The solar cell module is constituted of a transparent body 3 is installed on the side of an incident face 1, a transparent body 4 is installed on the side of the rear 2 and a transparent layer 5, whose refractive index is smaller than that of a peripehral part and a solar cell layer 6, which forms a pair with the transparent layer 5 are arranged sandwiched between both transparent bodies 3, 4. Many transparent layers 5 and many solar cell layers 6 are formed continuously along the longitudinal width direction of the solar cell module, while they form pairs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a solar cell module having light transmittance.

[0002]

2. Description of the Related Art Heretofore, several solar cell modules having both a function of absorbing light and generating power and a function of transmitting some light have been known. The following are two typical examples.

[0003] First, a structure in which a solar cell is sandwiched between two glass substrates and a part of sunlight is transmitted through a gap between the solar cells by adjusting an arrangement interval of the solar cells. Is known.

[0004] The second is a solar cell module having a structure in which a solar cell having countless fine holes is sandwiched between two glass substrates and a part of sunlight is transmitted through the holes of the solar cell. Are known.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a solar cell module having a light transmitting property, in which most of the light absorbed and contributing to power generation is direct light from the sun, and the light transmitted therethrough is partially. An object of the present invention is to provide a solar cell module having a feature of natural light.

In a conventional solar cell module having a light transmitting property, the light incident on the solar cell module is the light that is transmitted even if it is absorbed, including the two examples in the above-mentioned conventional technology. Even so, direct light from the sun and natural light are treated without distinction, and there is no solar cell module as the object of the present invention.

[0007]

The solar cell module according to the present invention employs a new structure which has not existed in the past, and utilizes the behavior of light obtained from the structure. Hereinafter, the structure of the solar cell module according to the present invention will be described.

A solar cell module according to the present invention has a transparent body made of a single or a plurality of members on each of an incident surface side and a rear surface side, and is sandwiched between both transparent bodies to form a transparent material or transparent material. The layer and the layer of the solar cell in which the solar cell paired with the transparent layer is arranged or formed are continuously formed along the solar cell module longitudinal width direction while forming a pair, and a large number is formed. I have. At this time, the transparent layer is formed so as to be inclined with respect to the incident surface, and is higher than any of a portion of the transparent body on the incident surface side in contact with the transparent layer and a portion of the rear transparent body in contact with the transparent layer. It is a thin band-like layer having a small refractive index and extending in the width direction of the solar cell module. Further, the layer of the solar cell is a strip-shaped layer formed in a direction perpendicular to the incident surface or in a direction opposite to the transparent layer and extending in the width direction of the solar cell module.

In the solar cell module according to the present invention having the above-described structure, the solar cell module is a new structure which has not existed in the past, and the most significant feature of the present invention is that the solar cell module is opposed to the solar cell rather than the peripheral portion. That is, a transparent layer having a small refractive index was provided. At the interface between the transparent layer and the transparent body on the incident surface side, light exhibits two types of properties: those having a certain incident angle are reflected and those having a certain incident angle are transmitted. The present invention utilizes such a property of light.

[0010] When a solar cell module having the above-described structure and the characteristics associated therewith is installed and used at an appropriate angle with respect to the ground surface, this solar cell module is a problem to be solved by the invention. Can achieve the object of the present invention described above.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A basic embodiment of a solar cell module according to the present invention will be described with reference to FIG. A transparent body 3 made of a single or a plurality of members is formed on the solar cell module incident surface 1 side, and a transparent body 4 made of a single or a plurality of members is similarly formed on the solar cell module back surface 2 side. Dressed between bodies 3 and 4,
A large number of pairs of the transparent layer 5 and the solar cell layer 6 are continuously formed along the longitudinal direction of the solar cell module while forming a pair. At this time, the transparent layer 5 is a layer having a refractive index n1 formed of a transparent material or a transparent substance. The refractive index n1 is the refractive index n2 of the transparent body 3 in contact with the transparent layer 5 and the refractive index n2 of the transparent body 4. It is a value smaller than any of the refractive indices n3 of the portion in contact with the transparent layer 5. Further, the transparent layer 5 is a thin layer, is formed so as to be inclined with respect to the incident surface 1 at an inclination angle θ1, extends in the width direction of the solar cell module, and has a band shape. On the other hand, the solar cell layer 6 is a layer in which the solar cells are arranged or formed, and the incident surface 1
The transparent layer 5 is formed perpendicularly to the transparent layer 5 or in a direction opposite to the transparent layer 5, and extends in the lateral width direction of the solar cell module similarly to the transparent layer 5 to form a belt shape. Assuming that the angle between the solar cell layer 6 and the incident surface 1 is θ2, θ2 is 0 including both the case where the solar cell layer 6 is vertical and the case where the solar cell layer 6 has an inclination.
It is an angle that satisfies ° <θ2 ≦ 90 °.

The above is the structure of the basic embodiment of the solar cell module according to the present invention. Hereinafter, a situation when light is incident on this will be described.

Light incident on the solar cell module from the incident surface 1 is divided into light traveling toward the transparent layer 5 and light traveling toward the layer 6 of the solar cell. Of these, those traveling toward the layer 6 of the solar cell are absorbed as they are and become photocurrents that contribute to power generation. Depending on the angle of incidence of the light, the light that has progressed to the piece or the transparent layer 5 is reflected at the interface 13 where the transparent layer 5 and the transparent body 3 are in contact with each other, and finally absorbed by the solar cell module. , Which pass through the interface 13 and eventually exit the solar cell module. Hereinafter, the behavior of the light traveling to the transparent layer 5 will be described in detail.

FIG. 2 is a partial cross-sectional view of a solar cell module according to a basic embodiment of the present invention. In this figure, the incident angle α of the incident light is the angle between the incident light and the incident surface 1, and α is 0 ° when the incident light is incident from vertically above the incident surface 1 as shown by an arrow. , In a direction that increases as the incident light tilts. When α is relatively small, the light incident on the solar cell module is at interface 1
When the light is reflected at 3 and becomes a large value exceeding a certain value, the light passes through the interface 13.

When α is relatively small, the incident light
Is reflected because the refractive index n1 of the transparent layer 5 is smaller than the refractive index n2 of the portion of the transparent body 3 on the side of the incident surface 1 which is in contact with the transparent layer 5, so that total reflection occurs. If the value of α is gradually increased, the angle reaches a limit at which total reflection occurs when α reaches a certain value, and total reflection does not occur at α larger than that value. Assuming that the limit angle of the total reflection is α0, incident light having an incident angle smaller than α0 is totally reflected, and incident light having an incident angle larger than α0 is transmitted. The state at this time is shown in FIG. 3 (in this figure, light 14 is light having an incident angle smaller than α0, and light 15 is light having an incident angle larger than α0).

The light that has traveled to the transparent layer 5 as described above is reflected or reflected at the interface 13 and is transmitted or transmitted. The following describes how the reflected and transmitted light behaves thereafter. I will explain.

First, the light is incident on the solar cell module at an incident angle smaller than α0, and is the light totally reflected at the interface 13, and this light is ultimately all absorbed by the solar cell. Because the interface 13 and the incident surface 1 are divergent, the light that has been totally reflected once at the interface 13 does not go out of the transparent body 3, and eventually the light of the solar cell This is because they are directed toward the layer 6.
This means that the angle θ formed by the solar cell layer 6 and the incident surface 1
It holds regardless of the size of 2. FIG. 4 shows how light having various incident angles α smaller than α0 is absorbed by the solar cell.

Next, the light is incident on the solar cell module at an angle of incidence larger than α0, and is transmitted without being totally reflected at the interface 13.
After passing through the transparent body 4 on the side, it eventually goes out of the solar cell module. Here, if the transparent layer 5 of the transparent body 4
If the refractive index n3 of the portion in contact with the transparent layer 5 is smaller than the refractive index n1 of the transparent layer 5, the light may be totally reflected at the interface between the transparent body 4 and the transparent layer 5, but in this embodiment, Since n1 is smaller than n3 in the solar cell module according to the basic mode, light passes through this interface without causing total reflection. FIG.
This shows how light having various angles of incidence α larger than the above transmits and exits the solar cell module.

As mentioned in the section of the means for solving the problems, the solar cell module according to the present invention exerts its effects only when used at an appropriate angle with respect to the ground surface. The appropriate angle is an angle that maximizes the properties of the solar cell module according to the present invention, or an angle that is sufficient to achieve the object of the present invention. What is necessary is just to determine arbitrarily in consideration of the use conditions at the time of use, a user's intention, etc. Among the appropriate angles, the most typical examples include a case where the solar cell module is installed vertically on the ground surface and a case where it is installed horizontally on the ground surface.

Here, when the solar cell module according to the present embodiment is used upright with respect to the ground surface,
Think about how it works. At this time, considering the behavior of the incident light as shown in FIGS. 4 and 5, this solar cell module can absorb most of the direct light from the sun in the daytime, while transmitting natural light. It can be seen that

The above is the appearance when light is incident on the solar cell module according to the basic embodiment of the present invention. Considering the behavior of light as described above, the inclination angle θ1 formed with the incident surface 1 of the transparent layer 5 is considered. And the refractive index n1, the refractive index n2 of the transparent body 3 on the incident surface 1 side in contact with the transparent layer 5, the refractive index n3 of the transparent body 4 on the back side 2 in contact with the transparent layer 5, and the layer of the solar cell. It can be understood that each value of the angle θ2 formed by the incident surface 6 of FIG. 6 can be basically any value within a range not departing from the basic embodiment according to the present invention. However, description of θ1 and θ2 will be supplemented below.

First, regarding θ1, since θ1 is an inclination angle, a value of 0 ° <θ1 <90 ° can be considered.
When the angle is close to 90 °, no substantial effect is obtained, so that the practically feasible range is 0 ° <θ1 <.
It is about 45 °.

Next, θ2 will be described.
Any value in the range of <θ2 ≦ 90 ° is possible,
Depending on the size, the ratio of the solar cell layer 6 to the entire solar cell module and the appearance of the solar cell module vary greatly. FIG. 6 is a perspective view of the solar cell module when θ2 is relatively small, and FIG. 7 is a perspective view of the solar cell module when θ2 is relatively large.

Finally, specific values are entered for the values of n1, n2, n3, θ1, and θ2, and the transparent bodies 3 and 4 are each formed as a single member by integral formation. Consider the behavior of light in a solar cell module according to the basic mode. At this time, since the transparent bodies 3 and 4 have the same refractive index in any part of the member, the refractive index n2 of the transparent body 3 in contact with the transparent layer 5 is the refractive index of the transparent body 3 and the transparent body 4 is transparent. The refractive index n3 of the portion in contact with the layer 5 is the refractive index of the transparent body 4. Possible values are n1 = 1.2, n2 = 1.5, n3 = 1.5,
Consider θ1 = 35 ° and θ2 = 45 °. Then, according to the calculation, the value of the angle α0 at the limit of total reflection at this time is α0 =
62.2 °. When this solar cell module is used standing upright with respect to the ground surface, incident light having α0 smaller than 62.2 ° is absorbed by the solar cell module, so that the solar altitude is larger than 27.8 °. Can be absorbed and natural light can be transmitted because incident light having α0 larger than 62.2 ° is transmitted. FIG. 8 shows the state at this time.

In the solar cell module according to the basic embodiment of the present invention, the specific shape of each component, the specific value of the refractive index, and other various specific values were not specified. However, when the solar cell module according to the present invention is actually used, considering the behavior of incident light as described above, the solar cell module can be used more preferably, and considering the solar cell module that is easier to manufacture, the components of the solar cell module are considered. Regarding some of the constituent members or the relationship between some of the constituent members, the following specific examples can be considered. Since each of these embodiments is considered to have a very great significance in actual production and use of the solar cell module according to the present invention, it is particularly mentioned in the claims. A total of four examples are shown for various components or relationships between components.

As an example of the transparent body 3 and the transparent body 4,
It is conceivable to form at least one of the transparent bodies 3 and 4 by bonding the transparent members 9 and 10 to the transparent substrates 7 and 8. FIG. 9 is a vertical cross-sectional view of the solar cell module according to the present embodiment when both of the transparent bodies 3 and 4 are formed by bonding the transparent members 9 and 10 to the transparent substrates 7 and 8. At this time, the transparent members 9 and 10 are shown in perspective views in FIG.
As shown in the above, one side is a plane, and the other side is obtained by carving a large number of irregularities having a pyramid shape, a triangular wave shape, or a sawtooth shape along the longitudinal direction of the member, The surface of one of the convex portions has an inclination angle θ
1 is a surface on which the inclined transparent layer 5 is formed, and the other surface is a surface on which the solar cell layer 6 inclined with the inclination angle θ2 is formed.

In the present embodiment, the method according to the present embodiment is the most general method for forming the transparent bodies 3 and 4,
They are listed because they seem reasonable.

As a second embodiment of the transparent body 3 and the transparent body 4, at least one of the transparent bodies 3 and 4 is provided on the transparent substrates 7 and 8 by a large number of prisms 11 and
It is conceivable to form them by joining them continuously. The transparent members 3 and 4 are placed on the transparent substrates 7 and 8 by the transparent members 9 and 10.
Considering the embodiment in the case of joining and forming,
In this embodiment, each of the transparent members 9, 10 in the above embodiment is replaced with a prism. It is considered that the cross-sectional shape of the prism bodies 11 and 12 is generally triangular, but a trapezoidal shape or the like can also be considered. In FIG. 11, the transparent body 3 on the incident surface 1 side is formed by joining a prism body 11 having a trapezoidal cross section to a transparent substrate 7, and the transparent body 4 on the back side 2 is formed on a transparent substrate 8 with a triangular cross section. FIG. 2 is a longitudinal sectional view of a solar cell module in a case where prism bodies 12 are formed by bonding.

An advantage of this embodiment is that the transparent layer 5
And each solar cell layer 6 to each prism 1
It becomes possible to form separately for 1 and 12. In addition, it is possible to directly form the solar cell on the prism body 11 or 12. This is effective for a solar cell of a type in which solar cells are directly formed on some kind of substrate, such as an amorphous silicon solar cell.

As an example of the transparent layer 5, the refractive index is approximately 1
It is conceivable to provide an air layer or a vacuum layer having a refractive index of 1. It is most desirable that the transparent layer 5 be an air layer or a vacuum layer, and the reason will be described below.

Although not described in the above description of the behavior of incident light in the basic embodiment of the solar cell module according to the present invention, generally, the limit angle of total reflection at an interface is determined by the angle of the material before and after the interface. It is determined by the difference in refractive index. At this time, the greater the difference between the refractive indices, the more the total reflection will occur even when the incidence of light on the interface is abrupt. Applying this to the case of the solar cell module according to the present invention, there is a large difference between the refractive index n1 of the transparent layer 5 and the refractive index n2 of the portion of the transparent body 3 on the incident surface 1 side in contact with the transparent layer 5. When I put it up, the transparent layer 5
Is reduced by reducing the value of the inclination angle θ1 formed by the
That is, even if the incidence of the light to the light is sudden, the total reflection occurs sufficiently. Reducing the value of θ1 is
This is useful because it leads to an increase in the ratio of the transparent layer 5 to the entire solar cell module and a reduction in the thickness of the solar cell module. In order to increase the difference between n1 and n2, it is necessary to use a refractive index as large as possible for n2. However, it is easier to make the refractive index of n1 as small as possible, that is, close to 1. , And effective. For this reason, it is most desirable to use an air layer or a vacuum layer having a refractive index of about 1 or 1 for the transparent layer 5.

As a specific example, an air layer having a refractive index n1 of about 1 is considered for the transparent layer 5, and the transparent body 3 on the side of the incident surface 1 is made of a single member integrally formed. Refractive index n2 of the portion in contact with 5 = refractive index of transparent body 3 =
Consider a solar cell module having θ1 such that the limit angle α0 at which total reflection occurs becomes 62.2 ° when 1.5 is set. Then, similarly, α0 = 62.2 °, but this is compared with FIG. 8 which is an example where n1 is n1 = 1.2. Then, in the case of this specific example, the value of the inclination angle θ1 formed by the transparent layer 5 and the incident surface 1 is calculated back by θ.
1 = 23.7 °, which indicates that θ1 = 35 ° in the case of FIG. FIG. 12 shows a vertical cross-sectional view of the solar cell module in this specific example. However, the value of θ2 is set to θ2 = 45 °, which is the same as the case of FIG.

Examples of the refractive index n2 of the portion of the transparent body 3 on the incident surface 1 side contacting the transparent layer 5 and the refractive index n3 of the portion of the transparent body 4 on the back surface 2 side contacting the transparent layer 5 are the same. The refractive index can be considered. The transparent body 3 described above,
In the case where the transparent member 4 is formed of the transparent substrates 7 and 8 and the transparent members 9 and 10, this means that the refractive indexes of the transparent members 9 and 10 on the incident surface 1 side and the rear surface 2 side are made equal. Also, the transparent bodies 3 and 4 are made transparent substrates 7 and 8 and prism bodies 11 and 12
In this case, the refractive indices of the prism bodies 11 and 12 on the incident surface 1 side and the rear surface 2 side are made equal. It is most desirable that the members before and after the transparent layer 5 have the same refractive index. The reason is described below.

As described above, each of n2 and n3 needs to be larger than the refractive index n1 of the transparent layer 5.
Satisfying only that condition is sufficient to achieve the object of the present invention, and there is no need for a refractive index relationship between n2 and n3. However, it is most desirable that n2 and n3 have the same refractive index. This is because the solar cell module can transmit light in the most natural form by having the same refractive index. This is because if the refractive index is the same before and after the transparent layer 5, even if the light straddles the transparent layer 5, the traveling direction of the light does not change before and after the light. This is because the incident angle becomes equal to the emission angle of the light exiting the solar cell module. The fact that the angle of incidence and the angle of emission of light are equal means that a single sheet of glass is placed in place of the solar cell module, and the same natural situation as when light passes through it can be obtained. The closer n2 and n3 are to each other, the more natural light is transmitted through the sheet glass. FIG. 13 shows the difference in the behavior of light between the case where n2 and n3 are equal and the case where there is a large gap between them (in this figure, the transparent bodies 3 and 4 are respectively shown for easy understanding). It is a single member formed by integral molding and has the same refractive index in any part of the member.)
The light 16 has the same refractive index and the light 17 has a difference in the refractive index.

[0036]

According to the solar cell module of the present invention, it is possible to realize a solar cell module that absorbs and generates most of the direct light from the sun and transmits pieces and natural light.

[Brief description of the drawings]

FIG. 1 is a perspective view of a solar cell module according to a basic embodiment of the present invention.

FIG. 2 is a view showing a method of setting an incident angle α of light in the basic embodiment of the present invention (a partial view of a longitudinal section).

FIG. 3 is a diagram showing incident light that causes total reflection and incident light that transmits without causing total reflection based on a limit angle α0 of total reflection in the basic embodiment of the present invention (partial view of a longitudinal section) Is).

FIG. 4 is a diagram showing a state in which light having various incident angles α smaller than an angle α0 of a limit of total reflection is absorbed by a solar cell in a basic embodiment of the present invention (part of a longitudinal section) It is a figure).

FIG. 5 is a view showing a state in which light having various incident angles α larger than the limit angle α0 of total reflection is transmitted through the solar cell module and emitted in the basic embodiment of the present invention (longitudinal section). FIG.

FIG. 6 is a perspective view of the solar cell module in a case where an angle θ2 formed by the layer 6 of the solar cell with the incident surface 1 is relatively small in the basic embodiment of the present invention.

FIG. 7 is a perspective view of the solar cell module in the case where the angle θ2 formed by the layer 6 of the solar cell and the incident surface 1 is relatively large in the basic embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view (partial view) of a solar cell module in an example in which a specific value is entered for each value such as a refractive index in the basic embodiment of the present invention.

FIG. 9 is a first example of a transparent body 3 and a transparent body 4, in which both transparent bodies 3 and 4 are formed by bonding transparent members 9 and 10 to transparent substrates 7 and 8, respectively. It is a longitudinal section of a module (it is a partial view).

FIG. 10 is a perspective view of transparent members 9 and 10 in the first embodiment of the transparent body 3 and the transparent body 4.

FIG. 11 is a second embodiment of the transparent body 3 and the transparent body 4, wherein the transparent body 3 on the side of the incident surface 1 is formed by joining a prism body 11 having a trapezoidal cross section to a transparent substrate 7; FIG. 4 is a longitudinal sectional view of a solar cell module in which a transparent body 4 on the rear surface 2 side is formed by joining a prism body 12 having a triangular cross section to a transparent substrate 8 (partial view).

FIG. 12 is a longitudinal sectional view (partial view) of a specific example of a solar cell module when an air layer having a refractive index n1 of approximately 1 is considered in the transparent layer 5 in the example of the transparent layer 5;

13 shows a refractive index n2 of a portion of the transparent body 3 on the incident surface 1 side in contact with the transparent layer 5, and a transparent layer 5 of the transparent body 4 on the back side 2
FIG. 7 is a diagram for explaining the behavior of light in the example of the refractive index n3 of a portion in contact with (a partial view of a longitudinal section).

[Explanation of symbols]

 Reference Signs List 1 incident surface 2 back surface 3 transparent body 4 transparent body 5 transparent layer 6 solar cell layer 7 transparent substrate 8 transparent substrate 9 transparent member 10 transparent member 11 prism body 12 prism body 13 interface 14 light 15 light 16 light 17 light

Claims (5)

[Claims] A transparent body (3, 2) comprising a single member or a plurality of members on each of an incident surface (1) side and a rear surface (2) side.
4), a transparent layer (5) made of a transparent material or a transparent material sandwiched between the transparent bodies (3, 4), and a solar cell paired with the transparent layer (5) are arranged. Or the solar cell module layer (6) formed is a large number of solar cell modules formed continuously along the solar cell module longitudinal width direction while forming a pair, and the transparent layer (5) is A portion of the transparent body (3) on the incident surface (1) side, which is in contact with the transparent layer (5), and a transparent body (3) on the back surface (2) side, which are formed inclined with respect to the incident surface (1). 4) a thin band-shaped layer having a smaller refractive index than any of the portions in contact with the transparent layer (5) and extending in the width direction of the solar cell module;
The layer (6) of the solar cell is formed in a strip extending in the width direction of the solar cell module in a direction perpendicular to the incident surface (1) or in a direction opposite to the transparent layer (5). A solar cell module, characterized by being a layer of: 2. The transparent body (3, 4), wherein at least one of the transparent body (3) on the incident surface (1) side and the transparent body (4) on the back surface (2) side comprises a transparent substrate ( 7,
8) A transparent member (9, 10) having a flat surface on one side, and a large number of concavities and convexities having a pyramid shape, a triangular wave shape, or a saw blade shape continuously provided along the longitudinal direction of the member. 2. The method according to claim 1, wherein
The solar cell module as described. 3. The transparent body (3, 4), wherein at least one of the transparent body (3) on the incident surface (1) side and the transparent body (4) on the back surface (2) is a transparent substrate (3). 7,
8) The solar cell module according to claim 1, wherein a large number of prism bodies (11, 12) are continuously arranged on the upper surface. 4. The transparent layer (5) has a refractive index of about 1
The solar cell module according to claim 1, wherein the solar cell module is an air layer or a vacuum layer having a refractive index of 1. 5. The refractive index of a portion of the transparent body (3) on the incident surface (1) side in contact with the transparent layer (5), or the refractive index of the transparent member (9) on the incident surface (1) side, or The refractive index of the prism body (11) on the incident surface (1) side is the refractive index of the portion in contact with the transparent layer (5) of the transparent body (4) on the back surface (2) side, or the back surface (2) side. The refractive index of the transparent member (10) or the prism body (12) on the back surface (2) side
The refractive index is equal to:
Or the solar cell module according to 4.