JPH0568867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a photovoltaic device that generates an electromotive force when irradiated with light.

(b) Prior Art A photovoltaic element in which a photoelectric conversion film that performs photoelectric conversion upon irradiation with light is directly formed on a support substrate is already known as disclosed in, for example, US Pat. No. 4,281,208. Such photovoltaic elements are currently in practical use as power sources for small consumer electronic devices such as calculators and pocket radios, while solar cells for so-called photovoltaic power generation, which are intended as household power sources, are currently being used as shown in Figure 6. Prepare a plurality of photovoltaic elements S ₁ to _{S 20} with the above structure,
A prototype panel has been manufactured in which it is incorporated into a non-light-transmitting frame 20 made of metal or resin, which makes it easy to attach it to a roof eave or a frame installed on a rooftop.

When installing a panel-shaped photovoltaic device on the above-mentioned mount, the normal direction of the light-receiving surface should be set south to match the mid-south direction of the sun at the vernal equinox (autumn equinox), taking into consideration the effective use of sunlight throughout the year. oriented toward the horizon. If the light-receiving surface is installed facing south during the vernal (autumn) equinox in this way, the shadows of the pair of frames located on both sides or on the north side will be projected onto the panel surface in seasons other than the vernal (autumn) equinox. Become. This shadow is longest at sunrise or sunset.

On the other hand, conventionally, photovoltaic elements S ₁ to
When incorporating S ₂₀ , the only consideration is that the proportion of the photovoltaic element in the panel area will be high. As a result, as shown in FIG. 7, the photoelectric conversion film 21
The length d of the adjacent photovoltaic elements S ₁ to _{S 20} in the direction of the light receiving surface and the distance δ from the frame 20 are set as small as possible.

However, the photovoltaic elements S ₁ to S ₂₀ and the frame 2
As the distance δ from 0 becomes smaller, as shown in Figure 7, sunlight irradiated from the direction south or north of the direction of the sun at the vernal (autumn) equinox will cause the photoelectric conversion film to perform photoelectric conversion upon light irradiation. 21 photosensitive surface PS
The light-receiving surface side end surface of the non-transparent frame 20
Since PE protrudes by a distance (height) H in the direction perpendicular to the light-receiving surface PS, that is, in the normal direction, the photoelectric conversion film 1 has a width W in the north-south direction of the light-shielded light-receiving surface PS. inhibits photoelectric conversion operation.

In particular, in order to obtain a high voltage with one photovoltaic element S ₁ to _{S 20} alone, a plurality of photoelectric conversion films 1, 1 . . . are connected in series in multiple stages. When only one photoelectric conversion film 1 is shielded from light, the output current of the photoelectric conversion film 1 that is not shielded and that is operating normally also decreases due to the above-mentioned light shielding. It is regulated by the value. Moreover, such a situation is likely to occur during the winter solstice or summer solstice, when the density of light incident on the panel surface is lowest, which hinders the effective use of solar cells throughout the year.

(C) Problems to be Solved by the Invention The present invention solves the problem in that the frame blocks light that is irradiated at a small angle of incidence with respect to the light-receiving surface of the photoelectric conversion film. The purpose of the present invention is to solve the problem of the frame blocking the sunlight irradiated by the frame, and to effectively utilize the irradiated light with such a small angle of incidence for photoelectric conversion regardless of the season. The purpose of this invention is to make the light receiving surface of the photoelectric conversion film sufficiently large while eliminating the reduction in the amount of light incident due to the above-mentioned light shielding.

(d) Means for Solving the Problems In order to solve the above problems, the present invention provides a photoelectric conversion film that performs photoelectric conversion upon irradiation with light, and a surface provided on the light-receiving surface side of the photoelectric conversion film that is in contact with the atmosphere. a light-transmitting light-receiving plate, and a non-light-transmitting frame surrounding at least a side surface of the light-receiving plate; When the distance to the light-receiving side end face is h, the distance l from the inner light-shielding periphery of the end face to the periphery of the photoelectric conversion film in the direction parallel to the light-receiving surface of the photoelectric conversion film is:
It has a configuration of approximately 0.87h.

(E) Effect As mentioned above, the distance l from the inner light-shielding rim of the light-receiving side end face of the frame to the periphery of the photoelectric conversion film in the direction parallel to the light-receiving surface of the photoelectric conversion film is calculated from the point corresponding to the light-receiving surface of the frame. By setting the distance h to the light-receiving end face in the direction orthogonal to the light-receiving surface to approximately 0.87 times, the irradiation light can reach the periphery of the photoelectric conversion film even near sunrise or sunset when the angle of incidence is small. At the same time, it suppresses the reduction in the light-receiving surface of the photovoltaic device as a whole, which would be caused by the peripheral edge of the photovoltaic conversion film becoming too much inside the photovoltaic device when the photovoltaic conversion film is made larger than this. It acts so that it becomes sufficiently large.

(f) Example Fig. 1 is a front view of the photovoltaic device of the present invention viewed from the direction of meridian at the vernal (autumn) equinox, and Fig. 2 is an enlarged sectional view taken along the -' line in Fig. 1. , Fig. 3 is an enlarged view of -' line in Fig. 1;
The figure is also an enlarged sectional view of the main part.

In FIGS. 1 to 4, S ₁ to _{S 20} are 10 to 30 cm x 10 to
Each of the photovoltaic elements S ₁ to _{S 20} is composed of 4×5 photovoltaic elements of about 30 cm in size, and in order to operate an electronic device by itself, for example, the photoelectric conversion film 1 is placed on the back side of the transparent support substrate 2. After being divided into five parts, they are electrically connected in series. More specifically, each of the photoelectric conversion films 1 is formed by glow discharge in a silane atmosphere with a transparent electrode layer 3 made of a light-transmitting conductive oxide such as SnO ₂ or ITO, when viewed from the support substrate 2 side. an amorphous silicon-based photoactive layer 4 with semiconductor junctions such as, and a back electrode layer 5 made of an ohmic metal such as Al that is in ohmic contact with the photoactive layer 4.
When the photoelectric conversion film 1 in such a laminated structure is irradiated with light, it is the portion where the three layers overlap each other that actually performs the photoelectric conversion operation. 6 is a resin film formed by screen printing to cover the back surface of the photoelectric conversion film 1.

The total thickness of the photoelectric conversion film 1 is approximately 2 to 3μ.
The thickness of the supporting substrate 2 is approximately 1 to 3 mm, which is extremely thin compared to the thickness of the supporting substrate 2, but for convenience of explanation, the two are not shown to be much different in the figure.

Reference numeral 7 denotes a light-transmitting light-receiving plate having a flat surface of the same size as the photovoltaic elements S ₁ to S ₂₀ arranged in a rectangular shape with 4 rows in the horizontal direction and 5 columns in the vertical direction. 4 x 5 photovoltaic elements S are attached via a translucent adhesive layer 8 on the main surface side of the translucent light-receiving plate 7 opposite to the light incident surface in contact with the atmosphere. ₁ to _S20 are adhesively fixed and mechanically supported. The adhesive layer 8 preferably has a refractive index substantially equal to the refractive index of the support substrate 2 and the light receiving plate 7 of each of the photovoltaic elements S ₁ to S ₂₀ . For example, if so-called plate glass for ordinary window glass is used as the support substrate 2 and the light receiving plate 7, the glass material is soda lime glass and has a refractive index of about 1.45 to 1.60, and a transparent glass material that is almost equal to this refractive index. The adhesive layer 8 is made of polyvinyl butyral (PVB) with a refractive index of approximately 1.48.
and ethylene vinyl acetate (EVA). Both PVB and EVA are commercially available in the form of sheets with a thickness of about 0.1 to several mm, for example, from DuPont in the United States. For example, by hot pressing at a reduced pressure of 10 Torr or less at a heating temperature of 80 to 170°C and a pressure of 0.5 to 5 kg/ ^cm2 , air bubbles are degassed from the cloudy sheet material. The light receiving plate 7 and the supporting substrate 2 are integrally bonded by the transparent adhesive material 8 which has become transparent.

9 is a protective film consisting of a three-layer structure of polyvinyl fluoride, Al, and polyvinyl fluoride that protects the back surfaces of the photovoltaic elements S _{1 to} S ₂₀ .
~ After connecting S ₂₀ on the back, connect the light receiving plate 7 above.
The adhesive layer 10 is made of the same material as the adhesive layer 8 and is adhesively fixed in the same process. 11 is a frame made of Al,
The side surface of the laminated structure of the light-receiving plate 7, the photovoltaic elements _S1 to _S20 , and the protective film 9 is surrounded to facilitate attachment to the pedestal.

Reference numeral 12 denotes a filler such as butyl rubber filled between the inner wall of the frame 11 and the side surface of the laminated structure to prevent rainwater from flowing into the side surface of the laminated structure.

Thus, the frame 11 serves as the light receiving surface of the photoelectric conversion film 1.
Light-receiving side end face in the direction perpendicular to the light-receiving surface PS from PS
Incident light I having a distance h to PE and having an incident angle greater than the projection angle θ on the north-south plane reaches at least the peripheral edge 1e of the photoelectric conversion film 1, and from the peripheral edge 1e. The inner photoelectric conversion film 1 is set as the irradiation range. Therefore, the smaller the projection angle θ is, the more effectively the photoelectric conversion operation can be performed even when the sun is tilted in the north-south direction from the direction at the vernal equinox (autumn equinox). On the other hand, reducing the projection angle θ means that the periphery of the light-receiving surface of the photoelectric conversion film is placed considerably inside, which reduces the area of the light-receiving surface in the photovoltaic device. . Therefore, setting the projection angle θ is important.

Now, for example, considering the effective use of sunlight throughout the year, if the normal to the light-receiving surface PS of the photoelectric conversion film 1 is set in the south-center direction at the vernal equinox (autumn equinox), then at 8 a.m. at the winter solstice (summer solstice) to 4:00 pm, the entire area of the photoelectric conversion film 1 is irradiated. At this time, the distance l from the inner light-shielding periphery IE of the light-receiving end face PE in the north-south direction to the periphery 1e of the photoelectric conversion film 1 in the direction parallel to the light-receiving surface PS of the photoelectric conversion film 1 is l=hcotθ
If the earth is spherical and the refractive index of air is 1, the above cotθ can be found as cotθ=tanχ/cos.

However, χ is the inclination of the Earth's rotation with respect to the orbital plane, that is, approximately 23.5 degrees, and is the rotation angle of the sun when the axis of rotation is the axis of rotation of the Earth and the position of the sun at noon is 0 degrees.

Therefore, the angle at around 8 am and 4 pm at the winter solstice (summer solstice) is approximately 60°, and χ = 23.5° and =
By substituting 60° into the above equation, cotθ=tan23.5°/cos60°=0.87 is obtained, and as a result, the distance l from the inner light-shielding edge IE to the edge 1e of the photoelectric conversion film 1 is l=0.87h. becomes. That is, as is clear from the above equation, if the distance l is set to be 0.87 times the distance h, sunlight will illuminate the entire area of the photoelectric conversion 1 from 8 a.m. to 4 p.m. at the winter solstice (summer solstice). On the other hand, if the distance l is made too large than 0.87 times h, the peripheral edge 1e will move inward to suppress the reduction in the light receiving surface, thereby preventing a decrease in power generation efficiency. be able to.

Therefore, the distance l from the inner light shielding edge IE of the frame 11 to the edge 1e of the photoelectric conversion film 1 is defined as the light receiving surface PS.
Abbreviation for distance (height) h from to the receiving end face PE
By multiplying by 0.87, the entire area of the photoelectric conversion film 1 can be irradiated with sunlight from 8:00 a.m. to around 4:00 p.m. even during the winter solstice (summer solstice). This means that it is possible to suppress the decrease in

Figure 5 shows the photoelectric conversion film 1 in the north-south direction as shown in Figure 1.
4 x 5 photovoltaic forces S ₁ to _{S 20} having the same configuration connected in series in multiple stages are arranged, and they are connected in series for approximately 0.87 h.
3 shows changes over time in the output characteristics at the winter solstice for sample A that satisfies the above, sample B that does not satisfy the above, and sample C that does not have the frame 11.

Sample A has h = 5 mm and l = 4.5 mm,
It satisfies approximately 0.87h above, and sample B has h=
5 mm, l=1.5 mm. For sample B, which does not satisfy the above condition approximately 0.87h, the output decreases by approximately 30% compared to sample C without frame 11 due to the light shielding phenomenon caused by frame 11 before 9 a.m. and after 3 p.m. On the other hand, in the case of sample A that satisfies the conditions, it has been demonstrated that the output hardly decreases due to light shielding. Also, the same sample A on days other than the winter solstice
When the output characteristics over time were measured for ~C, results with the same tendency were obtained.

(G) Effects of the Invention As is clear from the above description, the present invention provides the distance l from the inner light-shielding periphery of the light-receiving side end face of the frame to the periphery of the photoelectric conversion film in a direction parallel to the light-receiving surface of the photoelectric conversion film. By making 0.87 times the distance h from the part of the frame corresponding to the light-receiving surface to the light-receiving end face in the direction orthogonal to the light-receiving surface, the influence of light shielding by the frame arranged in the north-south direction is particularly eliminated. It acts to guide the irradiated light to the periphery of the photoelectric conversion film even near sunrise or sunset when the angle of incidence is small, and this also allows the periphery of the photoelectric conversion film to reach the inside of the photovoltaic device. This suppresses the reduction in the light-receiving surface of the photovoltaic power device as a whole, which would be caused by an excessive amount of light, and functions to make the light-receiving surface sufficiently large in an optimal state.

Therefore, it is possible to provide a photovoltaic device that can be effectively used for photoelectric conversion and suppresses power loss.

[Brief explanation of drawings]

1 to 4 show the photovoltaic device of the present invention, FIG. 1 is a front view, FIG. 2 is a sectional view taken along the line -' in FIG. 1, and FIG. −
4 is an enlarged sectional view of the main part, FIG. 5 is a graph of the change in output over time, FIGS. 6 and 7 are a conventional example, FIG. 6 is a front view, and FIG. 7 is a diagram of main parts. FIG. DESCRIPTION OF SYMBOLS 1... Photoelectric conversion film, 2... Support substrate, 7... Light receiving plate, 11... Frame.

Claims (1)

[Claims] 1. A photoelectric conversion film that performs photoelectric conversion upon irradiation with light, a light-transmitting light-receiving plate provided on the light-receiving surface side of the photoelectric conversion film and in contact with the atmosphere, and a non-light-transmitting light-receiving plate surrounding at least the side surface of the light-receiving plate. Equipped with a sexual framework,
When the distance from the light-receiving surface of the photoelectric conversion film in the frame body to the light-receiving side end surface in the direction perpendicular to the light-receiving surface is h, the distance from the inner light-shielding periphery of the end surface to the direction parallel to the light-receiving surface of the photoelectric conversion film A photovoltaic device characterized in that the distance l to the periphery of the photoelectric conversion film in the photoelectric conversion film is approximately 0.87h.