JP2014154414A - Dye-sensitized solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for achieving a good power generation efficiency which prevents a photoelectrode from being heated and deteriorated in an electrolyte injection step, in a dye-sensitized solar cell having the photoelectrode consisting of a semiconductor layer supporting a sensitization dye, a collecting electrode formed in contact with the photoelectrode, and a counter electrode opposed to the collecting electrode, in a light transmissive tubular container having sealed parts at both ends, the tubular container being filled with an electrolyte.SOLUTION: In one end sealed part of a tubular container, a metal pipe is sealed so as to be protruded from the inside of the tubular container toward the outside. An internal lead electrically connected with a collecting electrode penetrates through the metal pipe. Outside the tubular container, the metal pipe is chipped off and thereby connected with the internal lead.

Description

  The present invention relates to a dye-sensitized solar cell that converts light energy into electrical energy, and in particular, a collector electrode, a photoelectrode, and a counter electrode are disposed in a translucent tubular container, and an electrolytic solution is provided. The present invention relates to an enclosed dye-sensitized solar cell.

  Conventionally, solar cells that convert solar energy into electrical energy have been actively researched and developed as environmentally friendly and clean energy sources. Among them, a dye-sensitized solar cell has attracted attention as a low-cost solar cell with high photoelectric conversion efficiency, and various proposals have been made.

One example thereof is Japanese Patent No. 4840540 (Patent Document 1). In this dye-sensitized solar cell, an electrolytic solution is sealed in a translucent tubular container, and a collector electrode formed on the inner surface of the container; A photoelectrode made of a porous semiconductor layered thereon and adsorbed with a dye, and a counter electrode facing the photoelectrode are disposed, and sunlight is made incident on the photoelectrode to excite the electrons. It is taken out as electric energy by discharging.
This type of dye-sensitized solar cell is attracting attention because it does not require a high-vacuum chamber or the like for its manufacture, has a small burden on facilities, and can be manufactured at low cost.

A schematic structure of the solar cell according to FIG. 7A is shown.
In the figure, a dye-sensitized solar cell includes a collector electrode 24 made of a transparent conductive film and a photoelectrode made of a semiconductor layer in which a sensitizing dye is adsorbed on the inner surface of a main body 21 of a tubular container 20 made of transparent glass. 25, a coiled counter electrode 26 is disposed in the tubular container 20 so as to be spaced apart from the photoelectrode 25, and an electrolyte substance is provided in the tubular container 20. The electrolyte solution 27 is hermetically sealed.
At both ends of the main body portion 21 of the tubular container 20, flat sealing portions 22 and 23 are formed by heating and melting the glass constituting the tubular container 20 and crushing it, like a pinch seal in lamp technology. Has been sealed. A metal foil 33 is embedded in the sealing portion 22 on one end side, and an internal lead 31 from the counter electrode 26 and an external lead 35 protruding outward from the sealing portion 22 are connected to the metal foil 33. As a result, a conductive state is brought about.
Similarly, a metal foil 34 is embedded in the sealing portion 23 on the other end side, and the internal lead 32 connected to the counter electrode 26 via the insulating member 15 is connected to the metal foil 34. The external lead 36 protruding from the sealing portion 23 is connected. A collector electrode 24 formed on the inner surface of the main body 21 of the tubular container 20 extends into the sealing portion 23 so as to cover the internal lead 32, the metal foil 34, and the external lead 36. It is pinched and electrically connected to these.

  With such a configuration, an electrical connection is formed between the counter electrode 26, the internal lead 31, the metal foil 33, and the external lead 35 in one sealing portion 22, and the photoelectrode 25 in the other sealing portion 23. An electrical connection is formed between the collector electrode 24, the internal lead 32, the metal foil 34, and the external lead 36.

A process of sealing the electrolytic solution 27 in the tubular container 20 formed in this way will be described.
As shown in FIG. 7B, in the cylindrical main body 21 of the tubular container 20, the injection tube 40 is welded to the end region where the collector electrode 24 and the photoelectrode 25 are not formed on the inner surface, and the tubular container 20. Communicating with the inside.
The electrolytic solution 27 is injected from the injection tube 40 into the tubular container 20. After the electrolytic solution 27 is filled in the tubular container 20, the injection tube 40 is heated and melted with a burner or the like and sealed. With this melt-sealed tube, as shown in FIG. 7A, a sealing chip remaining portion 40 a is formed in the main body portion 21 of the tubular container 20.

  By the way, according to the above prior art, from the viewpoint of efficiency, the photoelectrode 25 is provided over the entire length of the tubular container 20 as much as possible. Therefore, the position where the injection tube 40 is provided is inevitably close to the end of the photoelectrode 25. Therefore, it is inevitable that the photoelectrode 25 in the vicinity of the injection tube 40 is also heated when the injection tube 40 is sealed by heating and melting. Since the pigment | dye of this photoelectrode 25 is comprised with the organic substance, when it receives a heating, it will deteriorate, and the malfunction that electric power generation efficiency will fall arises.

Japanese Patent No. 4840540

  In view of the above-mentioned problems of the prior art, the problem to be solved by the present invention is that a translucent tubular container has a photoelectrode comprising a semiconductor layer carrying a sensitizing dye, and a contact with the photoelectrode. In a dye-sensitized solar cell comprising a collector electrode formed by the above-mentioned method and a counter electrode facing the collector electrode, and the electrolyte solution is filled in the tubular container, a sealing operation after injection of the electrolyte solution Thus, a structure in which the influence of heating on the photoelectrode is avoided and deterioration of the photoelectrode is prevented is provided.

The dye-sensitized solar cell according to the present invention is sealed at one end sealing portion of a tubular container so that the metal tube protrudes from the inside of the tubular container and is electrically connected to the collector electrode. An internal lead penetrates the metal tube and is connected to the internal lead by crimping the metal tube outside the tubular container.
Further, the metal tube is characterized in that a sealing portion in which only the metal tube is crimped and sealed is provided at the protruding side end portion further than the crimp portion connected to the internal lead.
Also, the other end sealing portion of the tubular container is sealed so that a metal tube protrudes from the inside of the tubular container to the outside, and an internal lead electrically connected to the counter electrode has the metal lead The tube is penetrated and connected to the internal lead by crimping the metal tube outside the tubular container.

According to the dye-sensitized solar cell of the present invention, the electrolytic solution is injected into the tubular container through the metal tube sealed so as to penetrate one end sealing portion of the tubular container, and the metal is filled after the electrolytic solution is filled. Since the tube is crimped and sealed, and connected to the internal lead electrically connected to the collector electrode, the sealing operation is not accompanied by heating, and the photoelectrode is not thermally affected. Deterioration is prevented.
In addition, since only the metal tube is crimped and sealed on the projecting side of the crimping portion with the internal lead of the metal tube, the tubular container is more completely sealed.

The side sectional view (A) and transverse cross section (B) of the dye-sensitized solar cell of the present invention. The assembly process figure of the dye-sensitized solar cell of this invention. The electrolyte solution injection | pouring and sealing process figure of the dye-sensitized solar cell of this invention. The fragmentary sectional view of other Examples. Furthermore, the sectional side view of another Example. Furthermore, the cross-sectional view (A) and partial expanded sectional view (B) of another Example. The sectional side view of the conventional dye-sensitized solar cell.

FIG. 1 is a side sectional view showing the entire dye-sensitized solar cell of the present invention.
In a dye-sensitized solar cell, a tubular container 1 made of transparent glass is composed of a main body portion 2 and sealing portions 3 and 4 at both ends thereof, and a collector electrode made of a transparent conductive film is provided on the inner surface of the main body portion 2. 5 and a photoelectrode 6 made of a semiconductor layer to which a sensitizing dye is adsorbed are laminated.
A counter electrode 7 is disposed in the tubular container 1 so as to oppose the collector electrode 5, and the counter electrode 7 has a substantially cylindrical shape having a slit as shown in FIG. It is made of a metal plate that can be elastically expanded / contracted, and a cylindrical insulator 8 that can be expanded / contracted in the radial direction, for example, made of fiber cloth such as glass fiber or insulating resin fiber is covered around the metal plate. With this structure, the counter electrode 7 is in contact with the photoelectrode 6 with the insulator 8 interposed therebetween due to the elastic restoring force of the counter electrode 7.
With such a structure, the counter electrode 7, the collector electrode 5, and the photoelectrode 6 are disposed to be opposed to each other with a predetermined gap corresponding to the thickness of the insulator 8.
The insulator 8 is not limited to a cylindrical shape, and may be a sheet shape.

A metal tube 10 is sealed at the sealing portion 3 at one end of the tubular container 1 so as to protrude from the inside of the main body portion 2 of the tubular container 1 to the outside.
An internal lead 11 electrically connected to the collector electrode 5 is inserted into and penetrates the metal tube 10.
The metal tube 10 is crimped together with the internal lead 11 by press molding at the projecting end portion to form a crimping portion 15. With this structure, the inside of the tubular container 1 is hermetically sealed, and the metal tube 10 is electrically connected to the internal lead 11 and functions as an external lead.
Thus, an electrical connection of the metal tube (external lead) 10 -the internal lead 11 -the collector electrode 5 is formed.

On the other hand, the sealing part 4 at the other end is sealed by a pinch seal structure similar to that shown in FIG. 7, and the counter electrode 7 is sealed by the internal lead 12 with the metal foil 13 and the external lead 14 in the sealing part 4. Is electrically connected.
The tubular container 1 thus sealed inside is hermetically filled with an electrolyte solution 9 containing an electrolyte substance.

A schematic manufacturing method of the dye-sensitized solar cell having such a structure will be described with reference to FIG.
As shown in FIG. 2A, a counter electrode 7 fitted with an insulator 8 is disposed in contact with the collector electrode 5 and the photoelectrode 6 provided on the inner surface of the tubular container 1. . A metal tube 10 is arranged at the open end 1 a on one end side of the tubular container 1 so as to protrude from the inside of the tubular container 1, and an internal lead 11 connected to the collector electrode 5 is connected to the metal tube 10. It is inserted inside and penetrates to the outside.
On the other hand, the internal electrode 12, the metal foil 13 and the external lead 14 are connected to the counter electrode 7.
In this state, while flowing an inert gas such as argon from the open end 1b on the other end sealing portion side (metal foil 13 side) of the tubular container 1, the end portion 1a on the metal tube 10 side of the tubular container 1 is oxyhydrogenated. The sealing portion 3 is formed by heating and melting with a burner or the like and welding to the outer surface of the metal tube 10.

Next, at the other end, the sealing portion 4 is formed by a pinch technique.
That is, as shown in FIG. 2 (B), the other end portion 1b of the tubular container 1 is heated and melted while flowing an inert gas from the metal tube 10 into the tubular container 1, and the metal foil is crushed. The sealing portion 4 is formed so as to embed 13.
Thus, as shown in FIG. 2C, the electrode structure is built in the tubular container 1, and the metal tube 10 protrudes outward from the discharge container 1 at the sealing portion 3 on one end side thereof. A structure having a shape sealed in a state where the metal foil 13 is embedded in the other sealing portion 4 is formed.

Next, the step of injecting and filling the electrolytic solution into the tubular container 1 having such a structure and the step of sealing the metal tube 10 will be described with reference to FIG.
As shown in FIG. 3A, the tubular container 1 is erected so that the metal tube 10 faces upward. Then, an electrolytic solution 9 is injected from the metal tube 10 into the tubular container 1.
As shown in FIG. 3B, when the electrolytic solution 9 is filled in the tubular container 1, the upper end 15 of the metal tube 10 is pressure-bonded and sealed by the pressing means 18 with the internal lead 11 interposed, and the pressure-bonding portion 15 is sealed. Form. At this time, since the metal tube 10 is sealed without being heated, the collector electrode 5 is not heated via the internal lead 11.
As a result, as shown in FIG. 3C, the dye-sensitized solar cell in which the tubular container 1 is filled with the electrolytic solution 6 without providing the conventional electrolytic solution injection pipe in the tubular container 1. Is completed.

By the way, in the said Example, the metal tube 10 is sealed to the glass-made tubular container 1 by heat welding, and in this case, the tubular container 1 and the metal tube 10 are made of materials having a linear expansion coefficient. A combination is preferred. This is because if the material has a great difference in linear expansion coefficient, cracks may occur in the sealing portion 3 of the tubular container 1 during heat welding.
For this purpose, a combination in which the difference between the linear expansion coefficients α is within the range of ± 5 × 10 ⁻⁷ / ° C. is preferable.
Examples of specific combinations of materials are listed below.
(Example 1)
Tubular container: aluminosilicate glass (linear expansion coefficient α = 51 × 10 ⁻⁷ / ° C.)
Metal pipe: Molybdenum pipe (linear expansion coefficient α = 55 × 10 ⁻⁷ / ° C.)
(Example 2)
Tubular container: Kovar glass (linear expansion coefficient α = 55 × 10 ⁻⁷ / ° C.)
Metal tube: Kovar pipe (linear expansion coefficient α = 50 × 10 ⁻⁷ / ° C.)
(Example 3)
Tubular container: soda lime glass (linear expansion coefficient α = 90 × 10 ⁻⁷ / ° C.)
Metal pipe: Titanium pipe (linear expansion coefficient α = 88 × 10 ⁻⁷ / ° C.)

For the metal tube 10, a material having high corrosion resistance against the electrolytic solution 9 is suitable. For example, when the electrolytic solution 9 contains iodine having high reactivity with a metal, it is preferable to use a titanium member or a member whose surface is coated with titanium for the metal tube 10.
That is, in the above example, the metal pipes of Examples 1 and 2 are preferably titanium-coated. For example, it is preferable to prepare a molybdenum pipe and perform titanium coating on the surface with a film thickness of about several tens of nanometers by sputtering.

  Further, when the metal tube 10 is crimped via the internal lead 11, a gap may be formed between the inner surface of the metal tube 10 and the outer surface of the internal lead 11. In order to correct such a problem, as shown in FIG. 4, in the metal tube 10, only the metal tube 10 is pressure-bonded and sealed at the end portion further protruding than the pressure-bonding portion 15. Can also be provided separately.

By the way, although various metal materials can be used for the counter electrode 7, titanium oxide having an anatase type crystal structure is preferable from the viewpoint of power generation efficiency. The anatase-type crystal structure may change to a rutile-type or brookite-type crystal structure when heated, and these generate power generation efficiency lower than that of the anatase type.
For this reason, in the said Example, although it was set as the structure which uses the metal tube 10 by the sealing part 3 of the one end side of the tubular container 1, when forming the counter electrode 7 with the titanium oxide which has an anatase type crystal structure, In order to suppress the heating of the counter electrode 7, as shown in FIG. 5, in addition to using the metal tube 10 a (10) for the sealing portion 3 on one end side, the sealing portion 4 on the other end side is also used. Similarly, it is preferable that the metal tube 10b (10) is employed and the metal tube 10b electrically connected to the counter electrode 7 is electrically connected by crimping.

Moreover, in the said Example, although the collector electrode 5 which consists of a transparent conductive film on the inner surface of the tubular container 1, and the photoelectrode 6 were laminated | stacked and demonstrated, this collector electrode and photoelectrode were shown. However, the structure is not limited to this. For example, as shown in Japanese Patent Application Laid-Open No. 2012-256659, a photoelectrode is formed on the inner surface of a tubular container, and a collector electrode having an opening through which an electrolytic solution passes is provided on the inner surface. It may be.
6 (A) and 6 (B), the structure is shown. The photoelectrode 6 is formed on the inner surface of the tubular container 1 by firing or the like, and the collector electrode 5 is provided on the inner surface. The electrode 5 has an opening 5a through which the electrolytic solution can pass. Specifically, the collector electrode 5 can be composed of a metal perforated plate such as SUS or a metal net having a mesh structure.
The counter electrode 7 is in contact with the collector electrode 5 with an insulator 8 interposed therebetween.

Note that the counter electrode 7 is not limited to the structure of each of the above embodiments, and may have a coil shape as shown in FIG. 7. In this case as well, the outer periphery of the coil-shaped counter electrode is insulated. It is preferable to provide a body and form a predetermined gap between the collector electrode 5 and the counter electrode 7 to maintain an insulating state and prevent a short circuit due to contact between the two.
In this case, the internal lead connected to the counter electrode can be formed as an internal lead by integrally extending the coil wire of the coiled counter electrode as it is.

As described above, in the dye-sensitized solar cell according to the present invention, the internal lead connected to the collector electrode provided in the tubular container is inserted into the metal tube sealed through the sealing portion. Since the metal tube is crimped outside the sealing portion and connected to the internal lead and the metal tube is sealed, this metal tube is used before the metal tube is crimped and sealed. Therefore, it is not necessary to form an electrolyte injection tube in a tubular container as in the prior art, and therefore, it is not necessary to heat seal the injection tube. The thermal deterioration can be prevented without giving.
Further, since the metal tube is connected to the internal lead by pressure bonding outside the tubular container, no thermal work is involved, and there is no thermal influence on the photoelectrode from this aspect.
Furthermore, since only the metal tube is sealed by crimping at the protruding side end portion than the crimping portion of the metal tube, the tubular container is more completely sealed.

DESCRIPTION OF SYMBOLS 1 Tubular container 2 Main body part 3, 4 Sealing part 5 Collector electrode 5a Hole 6 Photoelectrode 7 Counter electrode 8 Insulator 9 Electrolyte 10 Metal tube 11, 12 Internal lead 13 Metal foil 14 External lead 15 Crimping part 16 Sealing part

Claims (3)

Inside a translucent tubular container having sealing portions at both ends, a photoelectrode comprising a semiconductor layer carrying a sensitizing dye, a collector electrode formed in contact with the photoelectrode, the collector electrode, In the dye-sensitized solar cell comprising a counter electrode facing the photoelectrode, and the tubular container filled with an electrolyte solution,
The one end sealing portion of the tubular container is sealed so that a metal tube protrudes from the inside of the tubular container,
An internal lead electrically connected to the collector electrode passes through the metal tube and is connected to the internal lead by crimping the metal tube outside the tubular container.
A dye-sensitized solar cell characterized by the above. 2. The dye-sensitized sun according to claim 1, wherein a sealing portion in which only the metal tube is pressure-bonded and sealed is provided at a protruding side end portion further than the pressure-bonding portion connected to the internal lead in the metal tube. battery. The other end sealing portion of the tubular container is also sealed so that the metal tube protrudes from the inside of the tubular container,
The internal lead electrically connected to the counter electrode penetrates the metal tube and is connected to the internal lead by crimping the metal tube outside the tubular container. 3. The dye-sensitized solar cell according to 1 or 2.

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