JP5397676B2 - Dye-sensitized solar cell - Google Patents

Description

  The present invention relates to a photoelectrode layer made of an N-type semiconductor carrying a dye that emits electrons upon receiving light on one side surface of a light-transmitting photoelectrode conductive layer, and spaced from the photoelectrode layer. A plurality of cells in which a counter electrode layer having conductivity facing each other and an electrolyte layer sealed between the photoelectrode layer and the counter electrode layer are stacked are electrically connected to each other. The present invention relates to a dye-sensitized solar cell.

In the dye-sensitized solar cell, conventionally, in order to increase the output voltage, a plurality of cells are electrically connected in series with each other, and a liquid electrolyte (hereinafter referred to as an electrolytic solution) is composed of a photoelectrode layer and a counter electrode layer. It is enclosed between (see, for example, Patent Document 1).
Since the cells are connected in series, if the redox couples (mainly iodine and triiodine ions) in the electrolyte are segregated due to short circuit between the electrolytes of adjacent cells, the power generation function is activated. If it continues to be used as it is, the portion of the cell where the redox pair segregates will break, and eventually the power generation function of all the cells connected in series will be lost.
For this reason, it is necessary to securely isolate the cells by adhering a seal wall between the cells so that the electrolytes of adjacent cells do not short-circuit.
However, since the seal wall that separates the electrolytes does not directly contribute to the power generation function, it is required to bond the thin seal wall so as to ensure as much space as possible for installing the cells.
Therefore, there is a drawback in that the adhesion performance of the seal wall is likely to deteriorate under the usage environment exposed to direct sunlight, and it is difficult to ensure the durability of the solar cell.
In addition, if the power generation capacity is reduced due to deterioration of some of the cells connected in series due to long-term use or partial shadows, the potential polarity of the cells may be reversed. It has become clear. If the cell is used for a long time in a state where the potential polarity of the cell is reversed, the cell may selectively fail and the electricity will not flow, and the function of the entire solar cell may be impaired.

JP 2006-260899 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dye-sensitized solar cell in which durability is easily ensured and a cell installation space is easily secured.

According to a first characteristic configuration of the present invention, there is provided a photoelectrode layer made of an N-type semiconductor in which a dye that emits electrons upon receiving light is supported on one side surface of a light-transmitting photoconductive layer, and the photoelectrode A plurality of cells in which a counter electrode layer having conductivity facing the layer with a gap therebetween and an electrolyte layer sealed between the photoelectrode layer and the counter electrode layer are stacked, and juxtaposed respective use conductive layer on one side of the common substrate having optical transparency, electrically connected in parallel to each other, the light electrode layer the optical electrode conductive layer is at a side edge of the cell A conductive layer for a counter electrode that extends in the parallel arrangement direction of the cells and is electrically connected to one side of the counter electrode layer, and is provided along the other side edge of the cell. to each of the extended portion and the counter electrode conductive layer of the layer, Tei collector member electrically conductive to these conductive layers are laminated There is a point.

In the case of the dye-sensitized solar cell of this configuration, a plurality of cells are electrically connected in parallel by arranging each of the photoelectrode conductive layers in parallel on one side of a common substrate having optical transparency. Therefore, it is not necessary to consider a short circuit between the electrolytes of adjacent cells, and a seal wall that separates the electrolytes of adjacent cells is not necessary.
In addition, since electricity can flow even when the power generation capacity is reduced due to a part of the cell being deteriorated by long-term use or being partially shaded, the function of the entire solar cell is less likely to be impaired.
Therefore, it is easy to ensure durability, and it is easy to ensure a large cell installation space.

Further, according to this configuration, the photoelectrode layer is electrically connected to the current collecting member through the extending portion of the photoelectrode conductive layer on one side edge side of the cell, and the counter electrode layer is connected to the other side of the cell. On the edge side, the current collecting member is electrically connected via the conductive layer for the counter electrode.
Therefore, the distance between the photoelectrode layer and the current collecting member electrically connected to the photoelectrode layer is shortened, and the voltage drop due to the photoelectrode conductive layer interposed between the photoelectrode layer and the current collecting member is reduced. Can be suppressed.
In addition, the distance between the counter electrode layer and the current collecting member that is electrically connected to the counter electrode layer can be shortened to suppress a voltage drop due to the counter electrode conductive layer interposed between the counter electrode layer and the current collecting member. it can. Therefore, resistance loss can be reduced.

According to the second characteristic configuration of the present invention, the current collecting members for the photoelectrodes laminated on the extending portion are connected in a comb-like shape by the current collecting members for photoelectrodes laminated along one side of the substrate. The counter electrode current collecting members laminated on the counter electrode conductive layer are connected in a comb-tooth shape by the counter electrode connecting current collecting members laminated along the other side of the substrate.

  With this configuration, a large number of current collecting members for a photoelectrode and a large number of current collecting members for a counter electrode are arranged in a compact manner by inserting a current collecting member for a counter electrode between adjacent current collecting members for a light electrode. The cells can be connected compactly along the sides of the substrate.

Cross section of dye-sensitized solar cell Plan view of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell Plan view showing manufacturing process of dye-sensitized solar cell

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a cross-sectional view of a dye-sensitized solar cell according to the present invention, and FIG. 2 shows a plan view thereof.

The dye-sensitized solar cell includes ten elongated rectangular cells 1.
Ten rectangular cells 1 are arranged in parallel on one side of a common rectangular glass substrate 2 (thickness: 1.1 mm) having light transmissivity, with the long sides adjacent to each other, and electrically in parallel with each other. A connection terminal 21a connected to a later-described photoelectrode current collecting member 12 and a connection terminal 21b connected to a counter electrode current collecting member 13 described later are provided.

  As shown in FIG. 1, each of the rectangular cells 1 has a photoelectrode layer 4 and a conductive layer opposite to the photoelectrode layer 4 on one side surface of the photoelectrode conductive layer 3 having optical transparency. A porous counter electrode layer 5 having electrical properties, an electrolyte layer 6 sealed between the photoelectrode layer 4 and the counter electrode layer 5, a conductive layer 7 for a counter electrode electrically conducting to the counter electrode layer 5, and a rectangular cell 1 is laminated with a covering layer 8 that hermetically covers 1 from the counter electrode layer 5 side.

  The rectangular cell 1 is formed side by side on one side of the glass substrate 2 with two adjacent combinations as one unit 9. In each unit 9, the conductive layers 7 for the counter electrodes of the two rectangular cells 1 are provided in series. The two rectangular cells 1 in each unit 9 are arranged symmetrically with the counter electrode conductive layer 7 in between.

  In adjacent units 9, the photoelectrode conductive layer 3 of the rectangular cell 1 in one unit 9 and the photoelectrode conductive layer 3 of the rectangular cell 1 in the other unit 9 are provided in series.

  The photoelectrode conductive layer 3 and the counter electrode conductive layer 7 are juxtaposed on one side of the glass substrate 2. These conductive layers 3 and 7 are provided in a state of being insulated from each other by separating a thin film (thickness 0.5 μm) of fluorine-doped tin oxide laminated on one side of the glass substrate 2 by a series of insulating grooves 10.

  As shown in FIG. 3, each photoelectrode conductive layer 3 is arranged in a comb-teeth shape connected to each other by a photoelectrode connection conductive layer 3a laminated along one side of the glass substrate 2 along the cell juxtaposition direction. ing. Each of the conductive layers for counter electrodes 7 is arranged in a comb-teeth shape connected to each other by a counter electrode connecting conductive layer 7 a stacked along the other side of the glass substrate 2 along the cell juxtaposition direction.

  The photoelectrode conductive layer 3 has a photoelectrode layer 4 on one side edge side between adjacent rectangular cells 1 and on one side edge side along the longitudinal direction of the rectangular cells 1 arranged at both ends in the cell juxtaposition direction. Longer than that of the rectangular cells 1, and a current collecting member 12 for the photoelectrode that is electrically connected to the photoconductive layer 3 is laminated on each of the extended portions 11. .

  As shown in FIG. 4, the photoelectrode current collecting members 12 are connected to each other in a comb-teeth shape by a photoelectrode connection current collecting member 12 a laminated on the photoelectrode connection conductive layer 3 a.

  The counter electrode conductive layer 7 is for adjacent photo electrodes along the other side edge side opposite to the one side edge side where the extended portion 11 of the photo electrode conductive layer 3 is present, on both side edges of the rectangular cell 1. It is provided between the conductive layers 3. The counter electrode conductive layer 7 is electrically connected to one side of the counter electrode layer 5.

  A counter electrode current collecting member 13 that is electrically connected to the counter electrode conductive layer 7 is laminated on each of the counter electrode conductive layers 7. As shown in FIG. 4, the counter electrode current collecting members 13 are connected in a comb shape by a counter electrode connecting current collecting member 13 a laminated on the counter electrode connecting conductive layer 7 a.

  Therefore, the photoelectrode layers 4 of each rectangular cell 1 are electrically connected to each other by the photoelectrode current collecting member 12 and the photoelectrode connection current collecting member 12a, and the counter electrode layers 5 of each rectangular cell 1 are used for the counter electrode. Since the current collecting member 13 and the counter electrode connecting current collecting member 13a are electrically connected to each other, the ten rectangular cells 1 are electrically connected to each other in parallel.

The manufacturing method of a dye-sensitized solar cell is demonstrated in order of a process.
After laminating a fluorine-doped tin oxide thin film on the glass substrate 2, the thin film is removed along a zigzag line with a width of 1 μm by scribing with a YAG laser to form a series of insulating grooves 10 as shown in FIG. As described above, the photoelectrode conductive layer 3 and the photoelectrode connection conductive layer 3a connected in a comb shape, and the counter electrode conductive layer 7 and the counter electrode connection conductive layer 7a connected in a comb shape are optically connected. The electrode conductive layer 3 and the counter electrode conductive layer 7 are provided alternately.

Next, as shown in FIG. 4, the photoelectrode current collecting member 12 and the photoelectrode connecting current collecting member 12 a, and the counter electrode current collecting member 13 and the counter electrode connecting current collecting member 13 a are laminated.
The photoelectrode current collecting member 12 and the photoelectrode connecting current collecting member 12a are screen-printed with a comb-like pattern of baking type silver paste across the photoelectrode conductive layer 3 and the photoelectrode connecting conductive layer 3a. And then baked at 500 ° C. to provide.
The counter electrode current collecting member 13 and the counter electrode connecting current collecting member 13a are printed on the counter electrode conductive layer 7 and the counter electrode connecting conductive layer 7a by screen printing a baking type silver paste in a comb-like pattern. It is fired at 0 ° C.

  After that, as shown in FIG. 5, the current collecting members 12 and 13 are used for anticorrosion so that the current collecting member 12 for the photoelectrode and the current collecting member 13 for the counter electrode are not corroded by contact with the electrolytic solution. Cover with coating layer 14.

As the anticorrosion coating material, an adhesive paste such as a low-melting glass paste capable of screen printing, an epoxy resin, or a polyisobutylene resin can be used.
In this embodiment, a low-melting glass paste is used to screen-protect the photoelectrode current collector 12 and the counter electrode current collector 13 with a predetermined pattern, and then baked at 500 ° C. for anticorrosion. A coating layer 14 is provided.

Next, as shown in FIG. 6, the photoelectrode layer 4 is laminated on the photoelectrode conductive layer 3.
The photoelectrode layer 4 at this stage is a porous N-type semiconductor (titanium oxide).

  The N-type semiconductor (photoelectrode layer) 4 is obtained by dispersing titanium oxide having an average particle diameter of 25 nm or less, mixing a cellulose-based binder, and then mixing while replacing with a solvent such as butyl carbitol. A paste prepared so as to have a concentration of 16 wt% is screen-printed on the photoelectrode conductive layer 3, dried, and fired at 450 ° C. to form.

  Next, in order to provide the electrolyte layer 6, a porous separator layer (average thickness 5 μm) 15 is laminated on the photoelectrode layer 4 as shown in FIG.

  Separator layer 15 is made by dispersing particles of 100% rutile titanium oxide having an average particle diameter larger than 250 nm and zirconium oxide having an average particle diameter of 20 nm, mixing a cellulose-based binder, and then mixing while replacing the solvent such as butyl carbitol. A paste prepared so that the solid content concentration of titanium oxide and zirconium oxide is finally 15 wt% is screen-printed on the photoelectrode layer 4, dried, and fired at 450 ° C. to form.

The separator layer 15 is formed in an L-shaped cross section so that the photoelectrode layer 4 and the counter electrode layer 5 do not directly contact each other, and one end of the separator layer 15 enters the insulating groove 10 to contact the glass substrate 2. I'm allowed.
As will be described later, the electrolyte layer 6 is provided by impregnating a separator layer 15 with an electrolytic solution 16.

  Next, as shown in FIG. 8, a counter electrode layer (thickness: 50 to 60 μm) 5 is laminated on the separator layer 15. The counter electrode layer 5 is formed in an L shape in cross section along the separator layer 15, and one side thereof is brought into contact with and electrically connected to the counter electrode conductive layer 7.

The counter electrode layer 5 has a ratio of 1: 5: 1 of carbon black having a specific surface area of 800 m ² / g or more, graphite having an average particle diameter of 5 μm, and titanium oxide having an average primary particle diameter of 6 nm, and after mixing a cellulose-based binder. , Butyl carbitol, etc., mixed with solvent substitution, and finally a paste prepared so that the solid content concentration becomes 30 wt% is screen-printed on the separator layer 15, dried, and baked at 450 ° C. .

  Next, the ruthenium complex is adsorbed to the N-type semiconductor 4 by immersing the glass substrate 2 laminated up to the counter electrode layer 5 in an ethanol solution of ruthenium complex for a predetermined time (24 hours).

Next, as shown in FIG. 9, a coating layer 8 is provided.
The covering layer 8 heat seals the seal layer 17 to the exposed portion along the outer peripheral portion of the glass substrate 2 in the photoelectrode connection conductive layer 3 a and the counter electrode conductive layer 7, and covers the rectangular core 1 on the seal layer 17. The heat sealing sheet 18 is provided by heat sealing.
As the seal layer 17 and the heat-sealing sheet 18, an ionomer Surlyn (trade name: manufactured by DuPont) is used.

  Next, the electrolyte solution 16 is injected from the electrolyte solution inlet 19 formed in the heat-sealing sheet 18, and the electrolyte layer 6 in which the separator layer 15 is impregnated with the electrolyte solution 16 is provided. By sealing 19 with a glass plate 20, the dye-sensitized solar cell shown in FIGS. 1 and 2 is completed.

  The electrolytic solution 16 is obtained by dissolving 0.05 mol / L iodine, 0.05 mol / L lithium iodine, and 0.05 mol / L 4-t-butylpyridine in 3-methoxypropionitrile.

[Other Embodiments]
In the dye-sensitized solar cell of the above-described embodiment, two rectangular cells are arranged side by side symmetrically across the conductive layer for the counter electrode, but adjacent rectangular cells are arranged in the same fixed posture. It may be juxtaposed.

1 Cell 2 Substrate 3 Photoelectrode Conductive Layer 4 Photoelectrode Layer 5 Counter Electrode Layer 6 Electrolyte Layer 7 Counter Electrode Conductive Layer 11 Extending Portion of Photo Electrode Conductive Layer 12 Current Collecting Member (Photo Electrode Current Collecting Member)
12a Photoelectrode connection current collecting member 13 Current collecting member (counter electrode current collecting member)
13a Counter electrode connection current collector

Claims (2)

A photoelectrode layer made of an N-type semiconductor carrying a dye that emits electrons upon receiving light is disposed on one side surface of a photoconductive conductive layer for light transmission, and is opposed to the photoelectrode layer with a gap. A plurality of cells in which a counter electrode layer having electrical conductivity and an electrolyte layer sealed between the photoelectrode layer and the counter electrode layer are stacked are light-transmitting each of the photoelectrode conductive layers. Are arranged in parallel on one side of a common substrate and electrically connected in parallel to each other ,
The conductive layer for the photoelectrode is extended in the side-by-side direction of the cells longer than the photoelectrode layer on one side edge of the cell,
A conductive layer for a counter electrode electrically conducting to one side of the counter electrode layer is provided along the other side edge of the cell;
A dye-sensitized solar cell in which a current collecting member that is electrically connected to the conductive layer is laminated on each of the extended portion of the photoelectrode conductive layer and the counter electrode conductive layer . The current collecting members for the photoelectrodes laminated on the extending part are connected in a comb-like shape with the current collecting members for photoelectrodes laminated along one side of the substrate,
Counter current collector members each other laminated to the conductive layer for the counter electrode, the dye-sensitized according to claim 1, characterized in that connected to the comb-shaped connection current collector for the counter electrode was stacked along the other side of the substrate Type solar cell.

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