JP5240902B2 - Solar cell - Google Patents

Description

The present invention provides an oxide having a translucent property at least on the light-receiving side of a pair of conductive substrates disposed opposite to each other with an electrolyte interposed therebetween, and an oxide provided with a dye therein. about the solar cells of the dye-sensitized type comprising a layer.

Conventionally, as a dye-sensitized solar cell, for example, a transparent glass substrate (conductive substrate) provided with a light-transmitting conductive film is disposed to face each other with the conductive film inward, and these conductive substrates The thing of the structure formed by interposing a liquid or solid gel electrolyte between these pairs is known (for example, refer patent document 1). Among these conductive substrates, an oxide layer made of titania (TiO ₂ ) adsorbed with a dye such as ruthenium is formed on the inner surface of the conductive substrate on the incident light receiving side (light receiving side). Yes.

 Such a dye-sensitized solar cell can be manufactured at a low price using an inexpensive material without using silicon, compared to conventional silicon solar cells (silicon single crystal, polycrystal). It is excellent in that it does not require large-scale capital investment. In addition, silicon has problems in terms of cost and resources, and an alternative means has been expected.

In addition, the dye-sensitized solar cell is not only a black pigment as in conventional silicon solar cells, but can be used in combination with a plurality of pigments such as cyan, magenta, and yellow. Design with high design is possible. Moreover, since a wide absorption band corresponding to the wavelength of incident light can be formed by combining a plurality of dyes, further increase in light energy conversion efficiency (photoelectric conversion efficiency) is expected.
Further, the degree of freedom of shape is high, and for example, a resin substrate such as plastic can be used as the conductive substrate, and the substrate can be formed into a curved surface. In addition, if such a resin substrate is used, the weight can be significantly reduced.
JP 2002-289270 A

However, in the past results, the dye-sensitized solar cell has not yet reached the silicon-based solar cell in terms of photoelectric conversion efficiency, and further improvement in photoelectric conversion efficiency has been demanded.
In addition, a dye-sensitized solar cell needs to seal an electrolyte between a pair of conductive substrates. Conventionally, this is done by using a sealing material or the like. It is necessary to stabilize the sealing over a long period of time and improve the durability.

The present invention has been made in view of the above problems, it aims to provide a light collection efficiency can be improved photoelectric conversion efficiency by increasing the, also solar cell of a dye-sensitized capable of improving the durability And

In order to achieve the above object, the present invention proposes the following means. That is, according to the present invention, among the pair of conductive substrates disposed opposite to each other with an electrolyte interposed, at least the conductive substrate disposed on the light receiving side has translucency, and the conductive substrate is disposed between the pair of conductive substrates. A dye-sensitized solar cell provided with an oxide layer provided with a dye, which is formed in a convex curved shape so as to cover the outside of the conductive substrate on the light receiving side, and has a light-transmitting property. The condensing part which has is arrange | positioned , The said condensing part consists of a film-shaped exterior body and the said electrolyte sealed inside the said exterior body, It is characterized by the above-mentioned .

  According to the solar cell of the present invention, the light-collecting portion having translucency is formed so as to protrude in a convex curved shape on the light receiving side where the light source (incident light) is, and has a convex lens shape having a spherical surface. It has a light focusing effect. In addition, since the condensing unit is disposed so as to cover the outside of the light receiving side conductive substrate, the focused incident light can be efficiently supplied to the conductive substrate. Therefore, the light collection efficiency is increased and the photoelectric conversion efficiency is improved.

  According to the solar cell of the present invention, the light-collecting portion is formed of a film-shaped exterior body, and an electrolyte made of, for example, liquid or solid gel is sealed inside the exterior body. Yes. That is, the electrolyte interposed between the pair of conductive substrates is disposed only between the pair as in the prior art and is not sealed with a sealing material or the like, but covers the outside of the conductive substrate on the light receiving side. And arranged outside the pair and used as a lens for the light collecting section.

 Therefore, the electrolyte is not used only for the oxidation-reduction means, but is also used as a light focusing means, thereby improving the photoelectric conversion efficiency. Further, according to this configuration, the electrolyte interposed between the pair of conductive substrates and the electrolyte disposed outside the conductive substrate on the light receiving side can be simultaneously formed in the same process, so that the productivity is excellent. .

In the solar cell of the present invention, the outer package may be made of a paraxylylene resin film formed by chemical vapor deposition.
If as this sealed to form the parylene hermetically the whole electrolyte by CVD, as in the prior art, there is no troublesome effort of installing a sealing material or the like for sealing the electrolyte, the work The characteristics are greatly improved. Moreover, since parylene is highly airtight and has excellent gas barrier properties, chemical resistance, heat resistance, cold resistance, and the like, the internal electrolyte is stably sealed for a long period of time, and durability is improved.

In the solar cell of the present invention, at least two pairs of the conductive substrates may be provided and arranged back to back so that the light condensing portions are directed outward.
According to the present invention, even if incident light is set in any direction, it is possible to generate power efficiently, so that the photoelectric conversion efficiency is further improved and it is possible to meet various demands.

Moreover, in the solar cell of the present invention, a plurality of pairs of the conductive substrates may be provided and electrically connected in series.
According to the present invention, the pair of electrically conductive substrates that are individually generated are electrically connected in series and modularized, so that the output voltage to be taken out as a whole increases, and it is possible to meet a wide variety of demands. it can.

Further, in the solar cell of the present invention, the pair of conductive substrates is arranged upright, and a gap is provided between the conductive substrate on the light receiving side and the exterior body of the light collecting unit. The electrolyte may be made of liquid and circulated between the inside of the exterior body and the pair of conductive substrates.
According to the present invention, the liquid electrolyte is heated by, for example, a conductive substrate that receives incident light and is heated, so that a natural space is formed between the inside of the outer casing of the light collecting unit and the pair of conductive substrates. It is designed to circulate and circulate. Therefore, the photoelectric conversion efficiency of the apparatus is stably maintained over a long period.

In the solar cell of the present invention, the conductive substrate arranged on the opposite side of the light receiving side of the pair of conductive substrates is a common electrode, and a plurality of the conductive substrates on the light receiving side are provided. It is good also as being done.
According to the present invention, among the pair of conductive substrates, the conductive substrate disposed on the opposite side of the light receiving side is formed as a common electrode, for example, extended or formed over a wide range. A plurality of conductive substrates on the light receiving side are arranged opposite to the electrodes. According to this, modularization of a plurality of solar cells required for practical use can be performed more easily, and productivity is improved.

According to the solar batteries of the dye-sensitized according to the present invention, can improve the photoelectric conversion efficiency by increasing the collection efficiency, also it can be improved durability.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side sectional view showing a schematic configuration of a solar cell according to the first embodiment of the present invention, and FIG. 2 is a schematic side sectional view showing a state in which the solar cell according to the first embodiment of the present invention is modularized. FIG. 3 is a schematic side sectional view showing a modification of the state in which the solar cell according to the first embodiment of the present invention is modularized, and FIG. 4 is a stand-up solar cell according to the first embodiment of the present invention. It is a schematic sectional side view which shows a state.

The solar cell 1 according to the first embodiment is a so-called dye-sensitized solar cell 1 that receives incident light L, converts the received light energy into electric power, and takes it out.
As shown in FIG. 1, the solar cell 1 includes a glass substrate 2 having a property (translucency) that transmits incident light L, and a back surface of the glass substrate 2 that is also translucent (the lower surface in FIG. 1). And a conductive substrate 4 laminated with a conductive film 3 made of indium-tin composite oxide (ITO). An oxide layer 5 made of porous titania (TiO ₂ ) is laminated on the back surface of the conductive substrate 4, and a ruthenium (Ru) dye is adsorbed to the oxide layer 5 in advance.

  Further, a conductive substrate 8 including a glass substrate 6 and a conductive film 7 is disposed so as to face the conductive substrate 4. The conductive substrate 8 has the conductive film 7 disposed on the side facing the conductive substrate 4. A spherical spacer 9 made of an insulator is disposed between the pair of conductive substrates 4 and 8, and a slight gap is provided. In this gap, an electrolytic solution (electrolyte) made of an iodine solution is provided. 10 is filled. The electrolytic solution 10 has an appropriate viscosity and has translucency. A negative electrode wire 11 is connected to the conductive film 3 of the conductive substrate 4, and a positive electrode wire 12 is connected to the conductive film 7 of the conductive substrate 8.

The oxide layer 5 that has received the incident light L emits electrons (e ⁻ ) from the retained ruthenium-based dye to the conductive film 3, and these electrons are sent out of the negative electrode 11 to the outside of the device. When electrons are taken into the conductive film 7 from the positive electrode wire 12, electricity flows and electric power can be taken out.

  Moreover, the outer side of the conductive substrate 4 arranged on the incident light L side (hereinafter abbreviated as “light receiving side”) of the pair of the conductive substrates 4 and 8 arranged in this way is covered. A convex curved condensing part 13 is formed. The condensing part 13 is formed by a transparent exterior body 14 made of a flexible film and the electrolyte solution 10 sealed inside the exterior body 14.

  The condensing part 13 has the structure which airtightly sealed the electrolyte solution 10 in the state of the droplet by covering the surface in which the droplet of the electrolyte solution 10 was formed with the exterior body 14. Specifically, the condensing unit 13 drops an appropriate amount of an electrolyte solution 10 having an appropriate viscosity onto a pair of conductive substrates 4 and 8, and the droplet of the electrolyte solution 10 has a spherical shape or a substantially approximate shape due to surface tension. On the surface formed in the dome shape, the electrolytic solution 10 is obtained by forming a flexible film outer package 14 made of a paraxylylene-based resin film (parylene) using a chemical vapor deposition method (CVD method). It is hermetically sealed in the form of drops. And the condensing part 13 formed with these exterior bodies 14 and the electrolyte solution 10 is made into the convex lens shape which has a spherical surface, and is provided with the light condensing effect.

  Paraxylylene resins are excellent in gas barrier properties, chemical resistance, heat resistance, cold resistance, and the like. Examples of such paraxylylene resins include polymonochloroparaxylylene (parylene C) and polyparaxylylene. (Parylene N), polydichloroparaxylylene (Parylene D), etc. can be mentioned. The parylene formed by this CVD method can be hermetically sealed in the form of droplets of the electrolytic solution 10 and can be easily miniaturized.

  In addition, a slight gap is provided between the inner surface of the outer package 14 of the light collecting unit 13 and the conductive substrate 4 on the light receiving side close to the inner surface. Moreover, the electrolyte solution 10 of the light condensing part 13 and the electrolyte solution 10 arrange | positioned between the pair of electroconductive board | substrates 4 and 8 are the same, are connected to each other area, and are in the state which can be convected It is said that.

 In addition, with respect to the electrolytic solution 10 interposed between the pair of conductive substrates 4 and 8, when the electrolytic solution 10 of the light collecting portion 13 is dropped as described above, the capillary solution in the step causes the gap between the pair. Therefore, no special additional process is required. And after the electrolyte solution 10 is filled between pairs, the process of forming the above-mentioned exterior body 14 is performed.

  As described above, according to the solar cell 1 of the present embodiment, the light-collecting part 13 having translucency protrudes in a convex curved shape on the light receiving side, has a convex lens shape having a spherical surface, and focuses light. Has an effect. Since the condensing unit 13 is disposed so as to cover the outside of the light-receiving side conductive substrate 4, the focused incident light L can be efficiently supplied to the conductive substrate 4. Therefore, the light collection efficiency is increased and the photoelectric conversion efficiency is improved.

 Further, the condensing part 13 is formed of an exterior body 14 whose exterior part is made of parylene, and the electrolytic solution 10 is sealed inside the exterior body 14. That is, the electrolytic solution 10 interposed between the pair of conductive substrates 4 and 8 is disposed only between the pair and not sealed with a sealing material or the like as in the prior art. It is arranged to cover the outside so as to cover the outside and to be used as a lens of the light collecting unit 13.

 Therefore, the electrolytic solution 10 is used not only as a redox means for generating electric power but also as a light focusing means, and the photoelectric conversion efficiency is increased. In addition, according to this configuration, the electrolytic solution 10 interposed between the pair of conductive substrates 4 and 8 and the electrolytic solution 10 disposed outside the conductive substrate 4 on the light receiving side can be simultaneously formed in the same process. So it is excellent in productivity.

 Further, by forming the exterior body 14 of the light collecting portion 13 from parylene, a sealing material or the like for sealing the electrolytic solution 10 in a liquid-tight manner is conventionally used as the peripheral edges of the pair of conductive substrates 4 and 8. It is not necessary to install in a part, and workability of manufacturing is greatly improved. Moreover, since parylene has high airtightness and is excellent in gas barrier properties, chemical resistance, heat resistance, cold resistance and the like, the internal electrolyte solution 10 is stably sealed for a long period of time, and durability is improved.

In order to put the solar cell 1 having such a configuration into practical use, a plurality of solar cells 1 may be used, for example, arranged in an array and modularized as shown in FIG.
That is, in FIG. 2, a plurality of solar cells 1 are arranged side by side on the same surface made of the common glass substrate 6 of the conductive substrate 8, and the negative electrode wire 11 and the positive electrode wire between the adjacent solar cells 1. 12 are connected to each other, and a plurality of solar cells 1 are electrically connected in series to form a module.

  According to this, since the pair of the conductive substrates 4 and 8 of the solar cell 1 that individually generates electric power is electrically connected in series with each other, the output voltage that can be taken out as a whole is increased, and more various requests are met. can do.

 Further, as in the modification shown in FIG. 3, the plurality of solar cells 1 may be formed by sharing the conductive film 7a using the common conductive substrate 8a and arranged side by side on the same surface. . If the conductive film 7 is collectively formed on the glass substrate 6 by vapor deposition or the like, a plurality of solar cells 1 required for practical use can be modularized more easily, and productivity is improved. improves.

  Further, as shown in FIG. 4, the solar cell 1 may be arranged with a pair of conductive substrates 4 and 8 standing. According to this, the electrolytic solution 10 is heated by the conductive substrate 4 that receives and heats the incident light L, and between the pair of the conductive substrates 4 and 8 and the inside of the exterior body 14 of the light collector 13. It circulates naturally between the convection. Therefore, the photoelectric conversion efficiency of the apparatus is stably maintained over a long period.

Next, a second embodiment of the present invention will be described.
FIG. 5 is a side sectional view showing a schematic configuration of a solar cell according to the second embodiment of the present invention.
In addition, the same code | symbol is attached | subjected to the same member as the solar cell 1 of above-mentioned 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 5, the solar cell 21 of the second embodiment is formed such that two pairs of upright conductive substrates 4 and 8 b are provided and these are arranged back to back. ing. That is, the two sets of conductive substrates 4 and 8b are arranged on one side (left side in FIG. 5) and the other side (right side in FIG. 5) with the respective light collecting portions 13 facing outward. In the glass substrate 6a disposed between the conductive substrates 4 and 8b, the conductive film 7 is formed on one surface and the other surface, respectively.

That is, the solar cell 21 has two sets of conductive substrates 4 and 8b that are integrated back to back by using the glass substrates 6a of the conductive substrates 8b in common.
According to this solar cell 21, even if the incident light L is set on one side and the other side, or it is set in any other direction, it is possible to generate power efficiently. The efficiency is further improved, and a wide variety of requests can be met. Moreover, even if it is space-saving, a photoelectric conversion efficiency can be improved.

The present invention is not limited to the first and second embodiments described above, and various modifications can be made without departing from the spirit of the present invention.
For example, the outer Sokarada 14 is not limited to parylene.

  Moreover, the electrolyte solution 10 may not be a liquid, for example, may be a solid gel form with translucency. Further, it may be any oxidation-reduction means for generating electric power, and may be other than iodine solution.

The conductive substrates 4, 8, 8a, 8b have been described as being formed by laminating glass substrates 2, 6, 6a and conductive films 3, 7, 7a made of ITO. However, the present invention is not limited to this configuration. Absent.
That is, instead of a glass substrate, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene, polyamide, cycloolefin polymer, polyethersulfine, polymethyl methacrylate, or the like having translucency is used. Also good. However, for the sake of baking titania, the glass substrate of this embodiment having heat resistance against heating at about 500 ° C. is more preferable.
Further, instead of the conductive film made of ITO, for example, fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), magnesium oxide (MgO) or Zinc oxide (ZnO) or the like may be used.

Further, the conductive substrates 8, 8a, 8b arranged on the opposite side of the light receiving side do not necessarily have translucency, and for example, a fluororesin or polytetrafluoroethylene may be used. .
Further, a catalyst layer may be provided on the inner surface of the conductive substrates 8, 8a, 8b, and Pt, Ru, Rh, Pd, C, etc. may be used as the material of the catalyst layer.

The oxide layer 5 has been described as being composed of titania (TiO ₂ ) on which a Ru-based dye is adsorbed, but is not limited to this configuration.
That is, as the type of pigment, for example, C ⁶⁰ derivatives, styryl benzothiazolium propyl sulfonate (BTS), or plant pigments having the property of receiving light and emitting electrons can be used. Can be designed by synthesizing, for example, three primary colors of cyan, magenta, and yellow. Here, the dye can be selected variously according to the wavelength of the incident light L. Further, it is more preferable to use a Ru-based dye as in the present embodiment because a wide range of wavelengths can be absorbed from the incident light L.
Further, instead of titania, zinc oxide (ZnO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), tungsten oxide (WO ₃ ), zirconium oxide (ZrO ₂₎ ), Lanthanum oxide (La ₂ O ₃ ), tantalum oxide (Ta ₂ O ₅ ), strontium titanate (SrTiO ₃ ), barium titanate (BaTiO ₃ ), or the like may be used.

  In FIG. 2 of the first embodiment, the plurality of solar cells 1 are electrically connected in series to increase the output voltage to be taken out as a whole. However, the present invention is not limited to this. For example, a booster circuit is used. You may comprise so that an output voltage may be increased.

  Further, in FIG. 5 of the second embodiment, it has been described that a pair of two conductive substrates 4 and 8b is formed on one side and the other side using a common glass substrate 6a. For example, the solar cells 21 may be formed by laminating the separate glass substrates 6 back to back and arranging two pairs of the conductive substrates 4 and 8 shown in FIG. .

It is a sectional side view which shows schematic structure of the solar cell which concerns on the 1st Embodiment of this invention. It is a schematic sectional side view which shows the state which modularized the solar cell which concerns on the 1st Embodiment of this invention. It is a schematic sectional side view which shows the modification of the state which modularized the solar cell which concerns on the 1st Embodiment of this invention. It is a schematic sectional side view which shows the state which installed the solar cell which concerns on the 1st Embodiment of this invention. It is a sectional side view which shows schematic structure of the solar cell which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1,21 Solar cell 4,8,8a, 8b Conductive substrate 5 Oxide layer 7a Conductive film 10 Electrolytic solution (electrolyte)
13 Condensing part 14 Exterior body L Incident light

Claims (6)

Of the pair of conductive substrates disposed opposite to each other with an electrolyte interposed therebetween, at least the conductive substrate disposed on the light receiving side has a light-transmitting property, and the oxidation is provided with a pigment between the pair of conductive substrates. A dye-sensitized solar cell provided with a physical layer,
Covering the outside of the conductive substrate on the light-receiving side, a convex curved surface is formed, and a condensing part having translucency is disposed ,
The condensing part is
A film-shaped exterior body;
A solar cell comprising: the electrolyte sealed inside the exterior body . The solar cell according to claim 1 ,
The solar cell according to claim 1, wherein the outer package is made of a paraxylylene resin film formed by chemical vapor deposition. The solar cell according to claim 1 or 2 ,
A solar cell, wherein at least two pairs of the conductive substrates are provided, and are arranged back to back so that the light condensing portions are directed outward. The solar cell according to any one of claims 1 to 3 ,
A solar cell comprising a plurality of pairs of the conductive substrates and electrically connected in series. The solar cell according to any one of claims 1 to 4 , wherein
The pair of conductive substrates is arranged upright;
A gap is provided between the conductive substrate on the light receiving side and the exterior body of the light collecting unit,
The solar cell according to claim 1, wherein the electrolyte is made of a liquid and can be circulated between the inside of the outer package and the pair of conductive substrates. The solar cell according to any one of claims 1 to 5 ,
Of the pair of conductive substrates, the conductive substrate disposed on the opposite side of the light receiving side is a common electrode,
A solar cell comprising a plurality of conductive substrates on a light receiving side.

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