Solar battery

Abstract

To provide a solar battery with a vertical conduction connection structure of which a power generation performance is improved.SOLUTION: A solar battery comprises a plurality of units. Each unit comprises: a power generation element that includes an electrode, a light absorption layer that is formed onto the electrode, and contains an electron capture agent and a color element, and an opposite electrode arranged so as to be opposite to the electrode. Also, the solar battery comprises: a vertical conductive sealing material that is formed to between a first unit and a second unit that are adjacent from the plurality of units, and conducts the electrode of the first unit and the opposite electrode of the second unit; and an external sealing material that is formed so as to surround an outer periphery of the plurality of units. The electrode is entered into the vertical conductive sealing material and the external sealing material. The opposite electrode is entered into the vertical conductive sealing material, and is not entered into the external sealing material.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to solar cells. [Background technology]

[0002] As a photoelectric conversion element, solar cells have been attracting attention because they are inexpensive and have high photoelectric conversion efficiency. Solar cells are expected to be used as energy harvesting elements. Solar cells are sometimes used as modules in which multiple solar cell units are connected in series to increase the light receiving area. Here, in order to connect multiple units in series, the electrodes provided on each unit may be connected vertically and electrically using a conductive sealing material. A solar cell module with this structure is sometimes called a Z-type module. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-093252 A Summary of the Invention [Problem to be solved by the invention]

[0004] In each unit, the only area that effectively contributes to power generation is the area where the electrodes are provided, and the areas where the electrodes are not provided are ineffective areas that do not contribute to power generation. Therefore, in order to improve the power generation performance of the solar cell, it is necessary to expand the area occupied by the electrodes in each unit as much as possible.

[0005] An object of the present disclosure is to provide a solar cell with a vertical conduction connection structure that has improved power generation performance. [Means for solving the problem]

[0006] A solar cell according to one embodiment includes a plurality of units. Each unit includes a power generating element including an electrode, a light absorbing layer formed on the electrode and including an electron collector and a dye, and a counter electrode disposed opposite the electrode. The solar cell also includes a vertical conductive sealant formed between adjacent first and second units of the plurality of units, and electrically connecting the electrode of the first unit to the counter electrode of the second unit, and an external sealant formed to surround the periphery of the plurality of units. The electrode is embedded in the vertical conductive sealant and the external sealant, and the counter electrode is embedded in the vertical conductive sealant but not in the external sealant. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a solar cell having a vertical conduction connection structure with improved power generation performance. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a solar cell according to an embodiment. [Diagram 2] FIG. 2 is a plan view of the dye-sensitized solar cell as viewed from the first substrate side. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a diagram for explaining the principle of power generation in one unit of the dye-sensitized solar cell. [Diagram 5] FIG. 5 is a graph showing the results of measuring the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the anode electrode is enlarged relative to the area of ​​the cathode electrode. [Figure 6] FIG. 6 is a graph showing the results of measuring the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the cathode electrode is enlarged relative to the area of ​​the anode electrode. [Figure 7] FIG. 7 is a graph showing the measurement results of the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the light absorbing layer is enlarged relative to the anode electrode. [Figure 8]FIG. 8 is a plan view showing a dye-sensitized solar cell in which a vertical conductive sealing material is formed only in a partial area between two adjacent power generating elements. [Figure 9A] FIG. 9A is a diagram showing the shape of the electrodes in the configuration of FIG. [Figure 9B] FIG. 9B is a diagram showing the shape of the counter electrode in the configuration of FIG. [Figure 10] FIG. 10 is a plan view showing a dye-sensitized solar cell in which a plurality of vertical conductive sealing materials are formed in a partial region between two adjacent power generating elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of a solar cell according to an embodiment. The solar cell is a dye-sensitized solar cell with a liquid electrolyte. The dye-sensitized solar cell 1 in FIG. 1 is a dye-sensitized solar cell module with a Z-type structure in which a plurality of dye-sensitized solar cell units U1, U2, U3, and U4 are connected in series. In FIG. 1, the number of units is four. The number of units is not limited to four.

[0010] As shown in Fig. 1, each of the units U1, U2, U3, and U4 of the dye-sensitized solar cell 1 is formed between a first substrate 11 and a second substrate 12. The first substrate 11 is a transparent substrate such as a glass substrate. The second substrate 12 is disposed so as to face the first substrate 11. Like the first substrate 11, the second substrate 12 is a transparent substrate such as a glass substrate.

[0011] An electrode 13 is formed at the position of each unit on the first substrate 11. The electrodes 13 are spaced apart such that there is no influence of leakage current between adjacent electrodes. The electrodes 13 are formed of a transparent conductive oxide (TCO) film such as indium tin oxide (ITO) or fluorine-doped tin oxide (FTO). Each electrode 13 is used as an anode electrode of the corresponding unit. The electrode 13 formed in one of the units U1 and U4, which are end units in the dye-sensitized solar cell 1, unit U4 in FIG. 1, is drawn out to the outside of the dye-sensitized solar cell 1. This drawn out electrode 13 is connected to a counter electrode 14 via a top-bottom conductive sealing material 19a. This counter electrode 14 is drawn out to the outside of the dye-sensitized solar cell 1. A terminal 131 is formed on the drawn out counter electrode 14. A wiring is drawn out from the terminal 131. This wiring is connected to one end of a load (not shown). The terminal 131 may be formed on the electrode 13 drawn out to the outside.

[0012] A counter electrode 14 is formed at the position of each unit on the second substrate 12. The counter electrodes 14 are spaced apart such that there is no influence of leakage current between adjacent electrodes. The counter electrodes 14 are formed of a transparent conductive oxide film (TCO) such as indium tin oxide (ITO) or fluorine-doped tin oxide (FTO) like the electrodes 13. Each counter electrode 14 is used as a cathode electrode of the corresponding unit. The counter electrode 14 formed in the other unit of the units U1 and U4, which are end units in the dye-sensitized solar cell 1, that is, the unit U1 in FIG. 1, is drawn out to the outside of the dye-sensitized solar cell 1. A terminal 141 is formed on the drawn out counter electrode 14. A wiring is drawn out from the terminal 141. This wiring is connected to the other end of a load (not shown). The terminal 141 may be formed on the side of the first substrate 11 by using a vertical conductive sealing material 19a.

[0013] An electron transport layer 15 is formed on the electrode 13 that constitutes the anode electrode of each unit. The electron transport layer 15 is made of titanium oxide (TiO x) a metal oxide film. The electron transport layer 15 may be provided to suppress loss due to the electrode 13 made of TCO, which has a higher resistance than metal. Furthermore, the formation of the electron transport layer 15 improves the adhesion of the light absorbing layer 16 to be further formed on the electron transport layer 15. As shown in FIG. 1, the electron transport layer 15 may be formed integrally with the electrode 13. In this case, the electron transport layer 15 in the unit U4 may be drawn out to the outside of the dye-sensitized solar cell 1, similar to the electrode 13 in the unit U4.

[0014] A light absorbing layer 16 is formed on each of the electron transport layers 15. The light absorbing layer 16 is a layer formed by adsorbing a dye to an electron collector. The electron collector is, for example, an aggregate of minute oxide semiconductors, for example, titanium oxide (TiO2). The dye is, for example, a ruthenium (Ru) dye (RU) (N719 dye, etc.). The electron collector is not limited to titanium oxide, but may be, for example, zinc oxide, tin oxide, tungsten oxide, niobium oxide, indium oxide, and a complex thereof. In addition, the dye is not limited to N719 dye. For example, N3 dye and BlackDye may be used as ruthenium-based dyes, and D149, xanthene, PVK, merocyanine, oxazine, etc. may be used as pure organic dyes.

[0015] A catalyst layer 17 is formed on the counter electrode 14 constituting the cathode electrode of each unit. The catalyst layer 17 is, for example, a platinum layer. The catalyst layer 17 may be formed integrally with the counter electrode 14. In this case, the catalyst layer 17 in the unit U1 may be extended to the outside of the dye-sensitized solar cell 1, similar to the counter electrode 14 in the unit U1.

[0016] An electrolyte 18 is filled between the light absorption layer 16 and the catalyst layer 17 of each unit. As a solvent for the electrolyte 18, for example, acetonitrile, methoxyacetonitrile, ethylene carbonate, etc. can be used. As a solute for the electrolyte 18, for example, iodine (I2), 1,2-dimethyl-3-n-propylimidazolium iodide (DMPImI), lithium iodide (LiI), 4-tert-butylpyridine (TBP), etc. can be used. As shown in FIG. 1, the electrolyte 18 is partitioned by upper and lower conductive sealants 19a provided at the boundary positions between the units U1 and U2, between the units U2 and U3, and between the units U3 and U4. The upper and lower conductive sealants 19a are formed by incorporating conductive fine particles as a conductive material containing metal particles into a resin having excellent solvent resistance, such as an acrylic resin or an olefin resin. The vertical conductive sealing material 19a bonds the first substrate 11 and the second substrate 12 together, and is provided between the opposing electrodes to provide electrical continuity between the units.

[0017] An external sealing material 19 is formed on the outermost periphery of the dye-sensitized solar cell 1. The external sealing material 19 bonds the first substrate 11 and the second substrate 12 together and prevents the electrolyte 18 from leaking out. That is, the electrolyte 18 is sealed by the first substrate 11, the second substrate 12, the vertical conductive sealing material 19a, and the external sealing material 19. The external sealing material 19, like the vertical conductive sealing material 19a, is formed by incorporating a conductive material containing metal particles into a resin having excellent solvent resistance, such as an acrylic resin or an olefin resin. The vertical conductive sealing material 19a and the external sealing material 19 may be formed integrally or separately.

[0018] Here, in the embodiment, the electrode 13 of one unit and the counter electrode 14 of the other unit out of two adjacent units are expanded to enter into the vertical conductive sealing material 19a.

[0019] Specifically, the electrode 13 of the unit U1 and the counter electrode 14 of the unit U2 are embedded in the vertical conductive sealing material 19a located between the units. The electrode 13 of the unit U2 and the counter electrode 14 of the unit U3 are embedded in the vertical conductive sealing material 19a located between the units. The electrode 13 of the unit U3 and the counter electrode 14 of the unit U4 are embedded in the vertical conductive sealing material 19a located between the units. On the other hand, the counter electrode 14 of the unit U1 and the electrode 13 of the unit U2 do not extend into the vertical conductive sealing material 19a located between the units. The counter electrode 14 of the unit U2 and the electrode 13 of the unit U3 do not extend into the vertical conductive sealing material 19a located between the units. The counter electrode 14 of the unit U3 and the electrode 13 of the unit U4 do not extend into the vertical conductive sealing material 19a located between the units.

[0020] With this configuration, the electrodes 13 and counter electrodes 14 of adjacent units are electrically connected via the vertical conductive sealing material 19a, and as a result, the units U1, U2, U3, and U4 are connected in series. In Fig. 1, the electron transport layer 15 and the catalyst layer 17 are also expanded to enter the vertical conductive sealing material 19a. However, the electron transport layer 15 and the catalyst layer 17 do not necessarily have to be expanded to enter the vertical conductive sealing material 19a.

[0021] Here, in order to prevent corrosion, etc., it is preferable that the electrode 13 and the counter electrode 14 do not penetrate the vertical conductive sealant 19a. For this purpose, it is preferable that the penetration length of the electrode 13 and the counter electrode 14 into the vertical conductive sealant 19a is shorter than the width of the vertical conductive sealant 19a. It is preferable that the length of the electrode 13 and the counter electrode 14 along the arrangement direction of the units is determined so that such a condition for the penetration length is satisfied and contact between the electrode 13 and the counter electrode 14 and the vertical conductive sealant 19a is ensured.

[0022] 2 is a plan view of the dye-sensitized solar cell 1 as viewed from the side of the first substrate 11. In FIG. 2, line II indicating the portion represented by the cross section of FIG. 1 is also shown.

[0023] In the embodiment, the area surrounded by the external sealing material 19 and the vertical conductive sealing material 19a of each unit constitutes a power generating element in each unit. The power generating element is a power generating element that contributes to power generation in each unit. In FIG. 2, one power generating element is shown as EL. One power generating element EL is composed of at least an electrode 13, a counter electrode 14, a light absorbing layer 16, and an electrolyte 18. The power generating elements EL of adjacent units are electrically connected via the vertical conductive sealing material 19a.

[0024] Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. As shown in Fig. 3, in a direction perpendicular to the arrangement direction of the units, the electrode 13 and the electron transport layer 15 are expanded to enter the external sealing material 19. In contrast, in a direction perpendicular to the arrangement direction of the units, the counter electrode 14 and the catalyst layer 17 are expanded to an extent that they do not come into contact with the external sealing material 19. Since the counter electrode 14 and the catalyst layer 17 do not come into contact with the external sealing material 19 in the direction perpendicular to the arrangement direction of the units, the electrode 13 and the counter electrode 14 are not electrically connected in the external sealing material 19.

[0025] Here, it is preferable that the electrode 13 does not penetrate the external sealing material 19. To achieve this, it is preferable that the length of the electrode 13 that penetrates into the external sealing material 19 is shorter than the width of the external sealing material 19. It is preferable that the length of the electrode 13 in the direction perpendicular to the arrangement direction of the units is determined so that such a condition for the penetration length is satisfied. It is also preferable that the length of the counter electrode 14 in the direction perpendicular to the arrangement direction is determined so that a gap is formed that ensures sufficient insulation from the external sealing material 19.

[0026] 4 is a diagram for explaining the power generation principle in one unit of a dye-sensitized solar cell. In the following example, the electron collector is titanium oxide (TiO2), the dye is a ruthenium (Ru) dye, and the electrolyte 18 is an iodine (I) electrolyte.

[0027] First, when light is incident on the dye-sensitized solar cell, the light is absorbed by the dye 16a formed on the substrate. The dye 16a is excited by absorbing the light. The reaction formula is, for example, shown in the following formula (1). Ru → Ru + +e - (1)

[0028] Electrons emitted from the excited dye 16a (e - The electrons injected into the electron collector 16b move to the electrode 13, which is an anode electrode.

[0029] On the other hand, electrons (e - The dye 16a that has lost the ion exchange function reacts with, for example, iodide ions (I - ) in electrolyte 18. - ) is an electron (e - ) to dye 16a, triiodide ion (I3 - The reaction formula is shown in the following formulas (2) and (3). Ru+e - →Ru (2) 3I - →I3 - +2e - (3)

[0030] The triiodide ion (I3 - ) is transported from the cathode electrode 14 to the counter electrode 14 by electrons (e - ) is received by the counter electrode 14. At this time, a potential difference is generated between the counter electrode 14 and the electrode 13. If a load is connected between the counter electrode 14 and the electrode 13, the electrons that have moved to the electrode 13 will move through the load to the counter electrode 14. Then, the electrons that have reached the counter electrode 14 will be converted into triiodide ions (I3 - ) is absorbed by the iodide ion (I3 - ) is the iodide ion (I - ) The reaction formula is shown, for example, in the following formula (4). I3- +2e - →3I - (4)

[0031] The above-mentioned redox reaction is repeated to generate electricity in the dye-sensitized solar cell unit. For this redox reaction to occur, the energy level of the excited dye 16a must be higher than the energy level of the electron collector 16b, and the energy level of the ground dye 16a must be lower than the energy level of the electrolyte 18.

[0032] As described above, in the embodiment, the electrode 13 of one of two adjacent units and the counter electrode 14 of the other unit are inserted into the vertical conductive sealing material 19a, which is the connection portion of the units, and the arrangement and size of the electrode 13 and the counter electrode 14 are determined so that only the electrode 13 is inserted into the external sealing material 19. With this configuration, the area occupied by the power generating element EL with respect to the unit is expanded to the extent that conduction between the electrode 13 and the counter electrode 14 is prevented at any portion other than the connection portion of the units.

[0033] 3 shows an example in which only the electrode 13 is embedded in the external sealing material 19. In contrast to this, from the viewpoint of preventing electrical continuity between the electrode 13 and the counter electrode 14 at locations other than the connection portion of the unit, it is also possible to adopt a configuration in which only the counter electrode 14 is embedded in the external sealing material 19. The effect of adopting a configuration in which the electrode 13, rather than the counter electrode 14, is embedded in the external sealing material 19 will be described below.

[0034] Figure 5 shows the measurement results of the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the anode electrode is enlarged relative to the area of ​​the cathode electrode. The short-circuit current ISC is one of the indices that express the power generation characteristics of a dye-sensitized solar cell, and is the current when the voltage is zero on the IV characteristic curve of the dye-sensitized solar cell.

[0035] Here, the horizontal axis of FIG. 5 is illuminance. FIG. 5 shows the measurement results under illumination of 200 lux, 1000 lux, and 1 sun (illuminance equivalent to direct sunlight in midsummer, approximately 100,000 lux). The vertical axis of FIG. 5 shows the anode electrode ratio and the ISC ratio. The anode electrode ratio is the area ratio of the anode electrode, i.e., the electrode 13, to the cathode electrode, i.e., the counter electrode 14. The ISC ratio is the ratio of the short-circuit current ISC at each illuminance when the short-circuit current ISC at 200 lux in a dye-sensitized solar cell in which the anode electrode and the cathode electrode are the same size is set to 1. A of FIG. 5 shows the anode electrode ratio for each illuminance, and B of FIG. 5 shows the ISC ratio for each illuminance. That is, FIG. 5 shows the measurement results of the ISC ratio at each illuminance for a dye-sensitized solar cell in which the area of ​​the anode electrode is 1.15 times that of the cathode electrode.

[0036] As shown in Figure 5B, at an assumed indoor illuminance of 1000 lux or less, the short-circuit current ISC increases by 1.1 times when the area of ​​the anode electrode is 1.15 times larger. Furthermore, at an assumed outdoor illuminance of 1 sun, the short-circuit current ISC increases by 1.15 times when the area of ​​the anode electrode is 1.15 times larger than that of the cathode electrode. In this way, the power generation performance improves regardless of the illuminance by increasing the area of ​​the anode electrode. This is because the increased area of ​​the anode electrode enhances the current collection effect of electrons excited by light irradiation.

[0037] FIG. 6 is a graph showing the results of measuring the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the cathode electrode is enlarged relative to the area of ​​the anode electrode.

[0038] Here, the horizontal axis of Fig. 6 is illuminance. The vertical axis of Fig. 6 is the cathode electrode ratio and the ISC ratio. C of Fig. 6 shows the cathode electrode ratio for each illuminance, and D of Fig. 6 shows the ISC ratio for each illuminance. In other words, Fig. 6 shows the measurement results of the ISC ratio for each illuminance for a dye-sensitized solar cell in which the area of ​​the cathode electrode is 1.20 times that of the anode electrode.

[0039] As shown in Figure 6D, at an assumed indoor illuminance of 1000 lux or less, the short-circuit current ISC remains at 1.0 even if the area of ​​the cathode electrode is increased by 1.20 times. On the other hand, at an assumed outdoor illuminance of 1 sun, the short-circuit current ISC increases to 1.18 times when the area of ​​the cathode electrode is 1.20 times that of the anode electrode. In this way, increasing the area of ​​the cathode electrode improves power generation performance only under high illuminance.

[0040] In order to enlarge the area of ​​the anode electrode and the cathode electrode as much as possible, it is conceivable to enlarge the area of ​​the anode electrode and the cathode electrode until they enter the sealing material. However, if the sealing material is conductive and both the anode electrode and the cathode electrode are configured to enter the sealing material in a portion other than the connection portion of the unit, the anode electrode and the cathode electrode in that portion will be conductive. In view of the relationship between the electrode area and the ISC ratio and the prevention of short circuits other than the connection portion, in the embodiment, a configuration is adopted in which only the anode electrode, i.e., the electrode 13, enters the external sealing material 19. This makes it possible to improve the power generation performance by enlarging the electrode area while preventing short circuits other than the connection portion.

[0041] Here, in the embodiment, the light absorbing layer 16 is not configured to be embedded in the vertical conductive sealing material 19a and the external sealing material 19. The effect of this will be described below.

[0042] Fig. 7 is a diagram showing the measurement results of the short-circuit current ISC for each illuminance in a dye-sensitized solar cell in which the area of ​​the light absorbing layer is enlarged relative to the anode electrode. The light absorbing layer in Fig. 7 is a TiO2 layer.

[0043] Here, the horizontal axis of FIG. 7 is illuminance. The vertical axis of FIG. 7 is TiO2 area ratio and ISC ratio. The TiO2 area ratio is the area ratio of the TiO2 layer, i.e., the light absorbing layer 16, to the anode electrode, i.e., the electrode 13. On the other hand, the area ratio of the anode electrode to the cathode electrode is 1. E of FIG. 7 shows the TiO2 area ratio, and F of FIG. 7 shows the ISC ratio for each illuminance. That is, FIG. 7 shows the measurement results of the ISC ratio for each illuminance for a dye-sensitized solar cell in which the area of ​​the TiO2 layer is 1.10 times that of the anode electrode.

[0044] As shown in Figure 7F, at an assumed indoor illuminance of 1000 lux or less, the short-circuit current ISC is only 1.01 times, even if the area of ​​the TiO2 layer is increased by 1.10 times. On the other hand, at an assumed outdoor illuminance of 1 sun, the short-circuit current ISC becomes 0.97 times when the area of ​​the TiO2 layer is 1.10 times that of the anode electrode. In other words, increasing the area of ​​the TiO2 layer does not have the effect of improving power generation performance.

[0045] Here, the cell gap of a dye-sensitized solar cell is generally several tens of μm, and the film thickness of the anode electrode and the cathode electrode is 1 μm or less. Therefore, even if the electrodes exist inside the sealing material, there is almost no effect on the cell gap. In contrast, the film thickness of the TiO2 layer is about several to 10 μm. If such a TiO2 layer exists inside the sealing material, it may affect the cell gap. For this reason, it is desirable to configure the light absorption layer so that it does not enter the sealing material.

[0046] As described above, in the embodiment, the electrode 13 of one of two adjacent units and the counter electrode 14 of the other unit are inserted into the vertical conductive sealing material 19a, which is the connection portion of the units, and the arrangement and size of the electrode 13 and the counter electrode 14 are determined so that only the electrode 13 is inserted into the external sealing material 19. With this configuration, a dye-sensitized solar cell with a vertical conductive connection structure is obtained in which the occupation area of ​​the power generating element EL relative to the unit is expanded to the extent that conduction between the electrode 13 and the counter electrode 14 is prevented at places other than the connection portion of the units.

[0047] Furthermore, by configuring the light absorbing layer so as not to penetrate into the vertical conductive sealing material 19a and the external sealing material 19, a desired cell gap required for a dye-sensitized solar cell can be ensured.

[0048] [Variations] A modified example of the embodiment will be described below. In the example of Fig. 2, the vertical conductive sealing material 19a is formed over the entire area between two adjacent power generating elements EL. In contrast, as shown in Fig. 8, the vertical conductive sealing material 19a may be formed only in a part of the area between two adjacent power generating elements EL. In this case, as in the above-mentioned embodiment, the electrode 13 of one unit and the counter electrode 14 of the other unit are inserted into the vertical conductive sealing material 19a, which is the connection part of the units, and the arrangement and size of the electrode 13 and the counter electrode 14 are determined so that only the electrode 13 is inserted into the external sealing material 19.

[0049] Fig. 9A is a diagram showing the shape of the electrode 13 in the configuration of Fig. 8. Fig. 9B is a diagram showing the shape of the counter electrode 14 in the configuration of Fig. 8.

[0050] 9A, the connection side of the unit of electrode 13 in the modified example is expanded to extend into external sealing material 19 and vertical conductive sealing material 19a. Comb-shaped protrusions 13a are formed at the position of vertical conductive sealing material 19a on the connection side of the unit of electrode 13 in the modified example.

[0051] Moreover, as shown in FIG. 9B, in the modified example, the opposing electrode 14 has a comb-tooth-shaped protrusion 14a only at the portion that is to be inserted into the vertical conductive sealing material 19a, and the portion other than the protrusion 14a is formed smaller than the electrode 13 so as not to be inserted into the external sealing material 19 and the vertical conductive sealing material 19a.

[0052] Here, since the conductive fine particles contained in the sealing material are anisotropic, even if the electrodes 13 of adjacent units are arranged from both directions in the same sealing material, there will be no short circuit as long as the electrodes 13 are spaced apart sufficiently. Therefore, in a modified example, the electrodes 13 of adjacent units may be expanded to the extent that they both enter the external sealing material 19 located therebetween. On the other hand, in order to increase the distance between the electrodes, it is desirable that the portions of the electrodes 13 adjacent to the protrusions 13a of the two electrodes 13 of the adjacent units are recessed portions 13b.

[0053] 10, a plurality of vertical conductive sealing materials 19a may be formed in a partial region between two adjacent power generating elements EL. In this case, too, protrusions are formed on the electrode portions of the electrode 13 and the counter electrode 14 that are inserted into the vertical conductive sealing materials 19a.

[0054] In the modified example described above, all sides of the anode electrode, including the connection portion with the cathode electrode, are inserted into the vertical conductive sealing material 19a or the external sealing material 19. This allows the area of ​​the anode electrode to be further enlarged, and a dye-sensitized solar cell with a vertical conductive connection structure having further improved power generation performance can be obtained.

[0055] (Other variations) Other modified examples will be described. In the above-mentioned embodiment and modified examples, examples of application to a dye-sensitized solar cell with a liquid electrolyte are shown. In contrast, the configurations of the above-mentioned embodiment and modified examples can be applied to configurations other than the dye-sensitized solar cell with a liquid electrolyte. For example, the dye-sensitized solar cell may be a dye-sensitized solar cell with a solid electrolyte. In the case of a dye-sensitized solar cell with a solid electrolyte, the only difference is that a solid electrolyte layer is interposed between the light absorption layer 16 and the catalyst layer 17 of each unit, rather than the electrolyte 18. The solid electrolyte layer may be, for example, the electrolyte 18 gelled by a gelling agent or the like.

[0056] As a further modification, the configurations of the above-described embodiment and modification may be applied to various solar cells other than dye-sensitized solar cells such as perovskite solar cells, etc. For example, in the case of a perovskite solar cell, the solid electrolyte layer may be replaced with a perovskite crystal layer.

[0057] In the above-described embodiment and modified examples, the first substrate 11 and the second substrate 12 are transparent substrates such as glass substrates. In contrast, the first substrate 11 and the second substrate 12 may be flexible substrates. In this case, the configurations of the above-described embodiment and modified examples may be applied to a monolithic structure in which electrodes and the like are formed on only one of the first substrate 11 and the second substrate 12.

[0058] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. In addition, the embodiments may be implemented in appropriate combination, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [Explanation of symbols]

[0059] 1 dye-sensitized solar cell, 11 first substrate, 12 second substrate, 13 electrode, 13a protrusion, 13b recess, 14 counter electrode, 14a protrusion, 15 electron transport layer, 16 light absorption layer, 17 catalyst layer, 18 electrolyte, 19 external sealing material, 19a upper and lower conductive sealing material, 131 terminal, 141 terminal.

Claims

1. An electrode; a light absorbing layer formed on the electrode and including an electron collector and a dye; a counter electrode disposed opposite the electrode; A plurality of units each having a power generating element including: a vertical conductive sealing material formed between adjacent first and second units among the plurality of units, the sealing material electrically connecting the electrode of the first unit and the counter electrode of the second unit; an external sealing material formed to surround the outer periphery of the plurality of units; Equipped with The electrode is embedded in the vertical conductive sealing material and the external sealing material, The counter electrode is embedded in the vertical conductive sealing material, but is not embedded in the external sealing material. Solar cell.

2. At least one vertical conductive sealing material is formed in a partial region between the first unit and the second unit, the external sealing material is formed in a region between the first unit and the second unit excluding the vertical conductive sealing material; The solar cell according to claim 1 .

3. the electrodes of the first unit and the electrodes of the second unit are embedded in the external sealing material formed in a region between the first unit and the second unit excluding the vertical conductive sealing material; The solar cell according to claim 2 .

4. The light absorbing layer is not in contact with the upper and lower conductive sealing material and the external sealing material. The solar cell according to claim 1 .

5. The vertical conductive sealing material is a resin containing conductive fine particles. The solar cell according to claim 1 .

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