JP7672221B2 - Solar Cell Module - Google Patents

Description

The present invention relates to a solar cell module.

Solar cells have been developed as a power supply source. For example, a solar cell has been disclosed in which a power generation layer is sandwiched between a first electrode layer and a second electrode layer that are optically transparent, and the first electrode layer has a larger area in plan view than the second electrode layer and the power generation layer (see, for example, Patent Document 1).

JP 2019-179898 A

In such solar cells, for example, extraction electrodes are provided on the second electrode layer and on the portions of the first electrode layer where the power generation layer and the second electrode layer are not provided. When the solar cell is mounted on a substrate, these extraction electrodes are connected to the substrate. However, there is a risk that sufficient connection strength may not be obtained between the solar cell and the substrate.

The present invention has been developed in consideration of the above problems, and aims to provide a solar cell module that can improve connection strength.

The solar cell module according to the present invention is characterized by comprising a solar cell having a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer, a first extraction electrode provided on the surface of the first electrode layer facing the second electrode layer in a location where the power generation layer and the second electrode layer are not provided, a second extraction electrode provided on the surface of the second electrode layer opposite the first electrode layer, a substrate connected to the first extraction electrode and the second extraction electrode, and an underfill portion provided between the substrate and the solar cell.

In the solar cell module, the first extraction electrode and the second extraction electrode may be made of a conductive resin.

In the solar cell module, the first extraction electrode and the second extraction electrode may be arranged asymmetrically in a plan view relative to the first electrode layer.

The solar cell module may include a sealing portion that seals the side surface of the power generation layer, the underfill portion may be in contact with the sealing portion, and the difference between the contact angle between the sealing portion and water and the contact angle between the underfill portion and water may be 45° or less.

In the solar cell module, the sealing portion of one or more corners may protrude toward the substrate from the side surface of the solar cell in the stacking direction of each layer of the solar cell, and may protrude toward the substrate from the sealing portion of other regions.

In the solar cell module, the sealing portion may extend onto the surface of the second electrode layer opposite the first electrode layer.

In the solar cell module, when the solar cell is cut in a cross section in the stacking direction of each layer, the extension amount of the sealing portion may be uneven, so that a part of the sealing portion may be grounded to the substrate, and a part of the sealing portion different from the part of the sealing portion may not be grounded to the substrate.

In a cross section of the solar cell in the solar cell module cut in the stacking direction of each layer, the contact area between the side surface of the sealing portion and the underfill portion may be 20% or less of the entire outer periphery of the solar cell.

In a cross section of the solar cell in the solar cell module cut in the stacking direction of each layer, the contact area between the substrate side surface of the sealing portion and the underfill portion may be 40% or less of the entire outer periphery of the solar cell.

In a cross section of the solar cell in the solar cell module cut in the stacking direction of each layer, the contact area between the sealing portion and the underfill portion may be 60% or less of the entire outer periphery of the solar cell.

In the solar cell module, the thickness of the solar cell may be 2.5 mm or less.

In the solar cell module, the power generation layer may be a solid.

In the solar cell module, the power generation layer may be a layer having semiconductor particles with a dye supported on the surface.

In the solar cell module, the contact area between the first and second extraction electrodes and the substrate may be smaller than the area of the solar cell in a plan view.

In the solar cell module, the underfill portion may extend to the side of the solar cell.

In the solar cell module, the underfill portion may be in contact with the entire surface or a portion of the substrate side of the solar cell.

The manufacturing method of the solar cell module is a manufacturing method of a solar cell module in which a power generation layer that generates power by incident light is sandwiched between a first electrode layer and a second electrode layer having optical transparency, and the first electrode layer has a larger area in a planar view than the second electrode layer and the power generation layer, and a substrate is connected to the solar cell, and is characterized in that a first extraction electrode is provided on the surface of the first electrode layer facing the second electrode layer in a location where the power generation layer and the second electrode layer are not provided, a second extraction electrode is provided on the surface of the second electrode layer opposite the first electrode layer, the first extraction electrode and the second extraction electrode are connected to the substrate, and an underfill portion is provided between the substrate and the solar cell.

The present invention provides a solar cell module that can improve connection strength.

FIG. 1A is a plan view (part 1) of a dye-sensitized solar cell according to a first embodiment during its manufacture, and FIG. 1B is a cross-sectional view taken along line II of FIG. FIG. 2A is a plan view (part 2) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 2B is a cross-sectional view taken along line II of FIG. FIG. 2A is a plan view (part 3) of the dye-sensitized solar cell according to the first embodiment during production, and FIG. 2B is a cross-sectional view taken along line II of FIG. FIG. 4A is a plan view (part 4) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 4B is a cross-sectional view taken along line II of FIG. FIG. 5A is a plan view (part 5) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 5B is a cross-sectional view taken along line II of FIG. FIG. 6A is a plan view (part 6) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 6B is a cross-sectional view taken along line II of FIG. FIG. 7A is a plan view (part 7) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 7B is a cross-sectional view taken along line II of FIG. FIG. 8A is a plan view (part 8) of the dye-sensitized solar cell according to the first embodiment during its manufacture, and FIG. 8B is a cross-sectional view taken along line II of FIG. 1A is a cross-sectional view illustrating a negative electrode lead electrode and a positive electrode lead electrode, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, which is inverted upside down. 1A and 1B are diagrams illustrating an example of a connection between a dye-sensitized solar cell and an electronic substrate. FIG. 13 is a diagram illustrating an underfill portion. 1A and 1B are diagrams illustrating contact angles with water. FIG. 13 is a diagram illustrating an underfill portion. FIG. 13 is a diagram illustrating an underfill portion. FIG. 13 is a diagram illustrating a sealing portion. 13A and 13B are diagrams illustrating an example in which the extension amount of the sealing portion relative to the substrate is uneven. 9( a ) is a diagram illustrating an example of the entire outer periphery of the dye-sensitized solar cell 20 in a cross section taken along line AA in FIG. 9( a ). 11 is a diagram illustrating an example of a contact area between a surface of a sealing portion facing an electronic board and an underfill portion. FIG. 11A and 11B are diagrams illustrating wraparound of a sealing portion; FIG. 13 is a diagram showing the results of a peel test in the examples. FIG. 13 is a diagram showing the results of a peel test in the examples. FIG. 13 is a diagram showing the results of a peel test in the examples. FIG. 13 is a diagram showing the results of a peel test in the examples.

(Embodiment)
The dye-sensitized solar cell (hereinafter referred to as solar cell) according to this embodiment will be described along with its manufacturing method.

First, as shown in Fig. 1(a) and Fig. 1(b), a rectangular glass substrate in a plan view is prepared as the light-transmitting substrate 10. The length of one side of the light-transmitting substrate 10 is 5 mm to 40 mm, for example, a square with a length of 10 mm. The thickness of the light-transmitting substrate 10 is 0.1 mm to 3 mm, for example, 1.1 mm. Note that a transparent plastic plate may be used as the light-transmitting substrate 10 instead of the glass substrate.

Next, an ITO (Indium Tin Oxide) layer is formed to a thickness of 0.1 μm to 0.5 μm as a light-transmitting electrode layer (hereinafter, the first electrode layer, also referred to as a transparent electrode) 11 on the light-transmitting substrate 10. Note that instead of an ITO layer, any of an FTO (Fluorine doped Tin Oxide) layer, a zinc oxide layer, a laminated film of an indium-tin composite oxide layer and a silver layer, and an antimony-doped tin oxide layer may be formed as the transparent electrode 11.

Furthermore, an alcohol solution prepared from titanium alkoxide is applied onto the transparent electrode 11, and the alcohol solution is heated and dried to form a reverse electron transfer prevention layer 12 with a thickness of about 5 nm to 0.1 μm. The drying temperature in this process is not particularly limited, and the reverse electron transfer prevention layer 12 is formed by heating to 450°C to 650°C, for example 550°C.

In addition, the reverse electron transfer prevention layer 12 is not formed on a portion of the corner area (hereinafter referred to as the corner portion) 10a of the light-transmitting substrate 10, so that the transparent electrode 11 is exposed. The area of the corner portion 10a is 0.2% to 5.6% of the area of the power generation layer, for example, 2%. The shape of the corner portion 10a is not particularly limited, but is triangular here.

2(a) and 2(b), a first titanium oxide paste 13a is formed on the reverse electron transfer prevention layer 12 by screen printing to a thickness of 1 μm to 20 μm, for example, 5 μm. In this example, PST-30NRD manufactured by JGC Catalysts and Chemicals is used as the first titanium oxide paste 13a. The average particle size of the titanium oxide particles contained in the first titanium oxide paste 13a is 5 nm to 50 nm, for example, 20 nm. The printing area of the first titanium oxide paste 13a on the light-transmitting substrate 10 is 0.01 cm ² to 4 cm ² , for example, 0.98 cm ^2. The first titanium oxide paste 13a is not limited to the above, and a paste obtained by kneading titanium oxide particles with a solvent such as ethyl cellulose may be used as the first titanium oxide paste 13a.

Next, as illustrated in Figures 3(a) and 3(b), a second titanium oxide paste 14a, PST-400C manufactured by JGC Catalysts and Chemicals, is formed on the first titanium oxide paste 13a by screen printing. The thickness of the second titanium oxide paste 14a is not particularly limited, but is set to 0.3 µm to 100 µm, for example, 42 µm, here. Furthermore, the printing area of the second titanium oxide paste 14a on the light-transmitting substrate 10 is set to 0.011 cm ² to 4.1 cm ² , for example, 1 cm ^2. Note that, similarly to the first titanium oxide paste 13a, a paste obtained by kneading titanium oxide particles with a solvent such as ethyl cellulose may be used as the second titanium oxide paste 14a.

The titanium oxide particles contained in the second titanium oxide paste 14a have an average particle size of 50 nm to 600 nm, for example 400 nm, which is larger than the average particle size in the first titanium oxide paste 13a. The particle size of titanium oxide can be determined by adjusting the magnification of a scanning electron microscope or a transmission electron microscope so that approximately 80 to 150 crystal grains are included in one image, taking multiple photographs so that there are a total of 400 crystal grains or more, and measuring the total number of crystal grains in the photographs to use the Feret diameter. The average value can be used as the average particle size.

The first titanium oxide paste 13a and the second titanium oxide paste 14a are not formed on the corners 10a of the light-transmitting substrate 10, so that the transparent electrodes 11 are exposed.

Next, as illustrated in Figures 4(a) and 4(b), the first and second titanium oxide pastes 13a and 14a are each heated to evaporate the organic matter, and the first and second titanium oxide pastes 13a and 14a become the power generation layer 13 and the reflective layer 14, respectively. The heating conditions for each titanium oxide paste 13a and 14a are not particularly limited. In this embodiment, each titanium oxide paste 13a and 14a is heated to a temperature of 450°C to 650°C, for example, 600°C. The heating time is 10 minutes to 120 minutes, for example, 30 minutes.

This results in a structure in which the top surface 13p and side surface 13q of the power generation layer 13 are each covered with the reflective layer 14. In addition, in the power generation layer 13 formed by the coating method, the side surface 13q is inclined with respect to the perpendicular line G of the top surface 13p, so that the power generation layer 13 becomes thinner from the center of the power generation layer 13 toward the end portion 13r. In this example, the reflective layer 14 is formed on all of the multiple side surfaces 13q of the power generation layer 13, but this embodiment is not limited to this. For example, the reflective layer 14 may be formed only on some of the multiple side surfaces 13q. Furthermore, the power generation layer 13 may be cylindrical with only one side surface 13q, and the reflective layer 14 may be formed only on a portion of that side surface 13q.

In this embodiment, the power generating layer 13 and the reflective layer 14 are formed from the titanium oxide pastes 13a and 14a, but the materials of the power generating layer 13 and the reflective layer 14 are not limited to these. For example, the power generating layer 13 and the reflective layer 14 may each be formed from semiconductor particles of an oxide of any of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, Cr, and Nb. Furthermore, _the power generating layer 13 and the reflective layer 14 may each be formed from particles of a perovskite oxide such as SrTiO3 or _CaTiO3 .

Next, as illustrated in FIG. 5(a) and FIG. 5(b), the power generation layer 13 and the reflective layer 14 are immersed in a solvent 15 containing a dye, and the dye is adsorbed to each of the power generation layer 13 and the reflective layer 14. Here, the solvent 15 is a toluene-based solvent in which MK-2 manufactured by Soken Chemical Industries, Ltd. is dissolved as the dye. The temperature of the solvent 15 is 0°C to 80°C, for example 50°C, and the immersion time is 10 minutes to 12 hours, for example 1 hour. Note that the titanium oxide particles contained in the power generation layer 13 have a smaller average particle size than the titanium oxide particles contained in the reflective layer 14, so many fine gaps are formed in the power generation layer 13. As a result, the amount of dye adsorbed to the power generation layer 13 is greater than the amount of dye adsorbed to the reflective layer 14.

The dye is not limited to the above, and metal complex dyes and organic dyes may be used as the dye. Among these, examples of metal complex dyes include transition metal complexes such as ruthenium-cis-diaqua-bipyridyl complex, ruthenium-tris complex, ruthenium-bis complex, osmium-tris complex, and osmium-bis complex. Zinc-tetra(4-carboxyphenyl)porphyrin and iron-hexacyanide complex are also examples of metal complex dyes.

Examples of organic dyes include 9-phenylxanthene dyes, coumarin dyes, acridine dyes, triphenylmethane dyes, tetraphenylmethane dyes, quinone dyes, azo dyes, indigo dyes, cyanine dyes, merocyanine dyes, xanthene dyes, and carbazole compound dyes.

6(a) and 6(b), 1 μL to 50 μL, for example, about 20 μL, of the solid electrolyte precursor 16 is dropped onto the reflective layer 14, thereby allowing the solid electrolyte precursor 16 to penetrate into the power generation layer 13 via the reflective layer 14. In this embodiment, the solid electrolyte precursor 16 is a solution in which iodine, 1,3-dimethylimidazolium iodide (DMII), acetonitrile, and polyethylene oxide with a molecular weight of 1,000,000 are mixed uniformly.

Then, the power generation layer 13 is heated to volatilize the excess acetonitrile contained in the solid electrolyte precursor 16, and the power generation layer 13 impregnated with the solid electrolyte is obtained. The heating conditions are not particularly limited, but the power generation layer 13 is heated to a temperature of 50°C to 150°C, for example, 100°C. The heating time is 1 minute to 60 minutes, for example, 30 minutes. The power generation layer 13 is then returned to room temperature. The solid electrolyte is also contained in the reflective layer 14. However, as described above, the titanium oxide particles contained in the power generation layer 13 have a smaller average particle size than the titanium oxide particles contained in the reflective layer 14, so many fine gaps are formed in the power generation layer 13. Therefore, the amount of solid electrolyte contained in the power generation layer 13 is greater than the amount of solid electrolyte contained in the reflective layer 14.

The electrolyte contained in the solid electrolyte precursor 16 is not limited to DMII. For example, iodine salts such as pyridinium salts, imidazolium salts, and triazolium salts, which are in a solid state near room temperature, or room-temperature molten salts in a molten state, can be used as the ionic liquid. Examples of such room-temperature molten salts include quaternary ammonium iodide compounds such as 1-methyl-3-propylimidazolium iodide, 1-butyl-3-methylimidazolium iodide (BMII), and 1-ethyl-pyridinium iodide.

Next, an example will be described with reference to FIG. 7(a) and FIG. 7(b). The positive electrode plate (second electrode layer) 17 is a titanium foil and a platinum layer. A platinum layer is formed on the surface of the titanium foil by sputtering. Here, titanium foil is used as the positive electrode plate, but the layer structure of the positive electrode plate 17 is not particularly limited. The platinum layer side of the positive electrode plate 17 is then adhered to the reflective layer 14. At this time, by adhering the positive electrode plate 17 to the reflective layer 14 in a reduced pressure atmosphere or in a vacuum, it is possible to prevent air bubbles from entering between the reflective layer 14 and the positive electrode plate 17. In addition to the above-mentioned platinum, the material of the positive electrode plate 17 can also be metals having catalytic functions such as palladium, rhodium, and indium. The positive electrode plate 17 may also be formed of graphite. Furthermore, the positive electrode plate 17 may be formed of carbon carrying platinum, indium-tin composite oxide, tin oxide doped with antimony, and tin oxide doped with fluorine. Other materials include organic semiconductors such as poly(3,4-ethylenedioxythiophene) (PEDOT) and polythiophene.

The shape and size of the positive electrode plate 17 are not particularly limited, but here, a square positive electrode plate 17 is used, excluding the corners 10a of the light-transmitting substrate 10. The length of one side of the positive electrode plate 17 is 5 mm to 40 mm, and the thickness of the positive electrode plate 17 is 50 μm to 200 μm.

Next, as illustrated in FIG. 8(a) and FIG. 8(b), ultraviolet curing resin is applied to each side of the light-transmitting substrate 10 to the positive electrode plate 17, and the ultraviolet curing resin is cured by irradiating ultraviolet rays to form a sealing portion 19. If the time between applying the ultraviolet curing resin and irradiating ultraviolet rays is too long, the ultraviolet curing resin will penetrate into the power generation layer 13 and cover its surface. To prevent this, it is preferable to irradiate ultraviolet rays within 10 minutes after applying the ultraviolet curing resin. In FIG. 8(b), the cross-sectional view of line I-I in FIG. 8(a) is inverted upside down. The sealing portion 19 may extend to the surface of the light-transmitting substrate 10. The sealing portion 19 may also extend to the surface of the light-transmitting substrate 10 of the positive electrode plate 17.

The solar cell 20 according to this embodiment is now completed. As described above, in the solar cell 20, the power generation layer 13 that generates power when light is incident on it is sandwiched between the transparent electrode 11, which has optical transparency, and the positive electrode plate 17.

In this solar cell 20, the transparent electrode 11 functions as a negative electrode, and iodide ions (I ⁻ ) and triiodide ions (I ₃ ⁻ ) contained in the solid electrolyte filled in the power generation layer 13 are carriers for conducting electrons between the transparent electrode 11 and the positive electrode plate 17. When the end of the cross section of the power generation layer 13 including the reflective layer 14 is observed with various microscopes such as a scanning electron microscope and a transmission electron microscope, it can be confirmed that the transparent electrode 11 and the reflective layer 14 are in contact with each other.

Furthermore, in this embodiment, as described above, the average particle size of the titanium oxide particles contained in the second titanium oxide paste 14a is larger than the average particle size of the titanium oxide particles contained in the first titanium oxide paste 13a. Reflecting this, the average particle size of the titanium oxide particles contained in the reflective layer 14 is larger than the average particle size of the titanium oxide particles contained in the power generation layer 13. As a result, the light reflectance of the reflective layer 14 is larger than the light reflectance of the power generation layer 13.

This solar cell 20 is mounted on an electronic board. As shown in FIG. 9(a), a negative electrode extraction electrode 21 (first extraction electrode) is provided on the surface of the transparent electrode 11 facing the positive electrode plate 17, in an area (corresponding to the corner 10a) where the power generation layer 13 and the positive electrode plate 17 are not provided. A positive electrode extraction electrode 22 (second extraction electrode) is provided on the surface of the positive electrode plate 17 opposite the transparent electrode 11. For example, the positive electrode extraction electrode 22 is located approximately in the center of the positive electrode plate 17 in a plan view. The material of the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 is, for example, a conductive resin containing a metal such as silver. FIG. 9(b) is a cross-sectional view of line A-A in FIG. 9(a) flipped upside down.

Because the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 are made of conductive resin, the solar cell 20 can be connected to an electronic substrate 60 or the like using the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22, as illustrated in FIG. 10(a). However, if the solar cell 20 is connected to the electronic substrate 60 using only conductive resin, the solar cell 20 is likely to peel off from the electronic substrate 60 due to external pressure, as illustrated in FIG. 10(b).

In this embodiment, as shown in FIG. 11, the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 are connected to the electronic substrate 60, and an underfill section 50 is disposed between the solar cell 20 and the electronic substrate 60. This increases the connection strength between the solar cell 20 and the electronic substrate 60, improving durability against external pressure. It is preferable that the underfill section 50 also contacts the sealing section 19. The underfill section 50 has insulating properties.

In particular, as illustrated in FIG. 9(a), in a plan view of the solar cell 20 according to this embodiment, the positional relationship between the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 is not point symmetric with respect to the center of the solar cell 20, but is asymmetric. This is because one of the extraction electrodes is disposed at a biased position (for example, at an end) in order to increase the effective power generation area relative to the area. In the example of FIG. 9(a), the positive electrode extraction electrode 22 is located approximately in the center, and the negative electrode extraction electrode 21 is located at a corner. In this way, in a plan view of the solar cell 20, the range in which the conductive resin exists is biased. Due to this bias, the connection strength between the solar cell 20 and the electronic board 60 is weakened against external pressure. When the positional relationship between the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 is asymmetric, a remarkable effect can be obtained by using the underfill section 50.

The higher the affinity between the sealing portion 19 and the underfill portion 50, the stronger the connection strength between the solar cell 20 and the electronic substrate 60. Therefore, it is preferable that the affinity between the sealing portion 19 and the underfill portion 50 is high. Affinity represents the ease with which substances mix together. Furthermore, materials with similar polarities tend to mix together easily, and therefore materials with similar polarities have a high affinity. Polarity can be determined using the contact angle θ between the organic interface and water.

As shown in FIG. 12(a), the smaller the contact angle θ with water, the higher the polarity. As shown in FIG. 12(b), the larger the contact angle θ with water, the lower the polarity. Materials with a small difference in the contact angles θ (contact angle difference) have similar polarity and high affinity. Therefore, for example, it is preferable that the difference (contact angle difference) between the contact angle between the sealing portion 19 and water and the contact angle between the underfill portion 50 and water is 45° or less.

Resins that can be used for the underfill portion 50 and the sealing portion 19 may be, for example, any mixture or combination of acrylic, urethane, silicone, nylon, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, and polyvinylidene fluoride resins. Regarding each compound, erythritol type poly(meth)acrylate compound, glycidyl ether type (meth)acrylate compound, bisphenol A type di(meth)acrylate compound, cyclodecane type di(meth)acrylate compound, methylol type (meth)acrylate compound, glycol type di(meth)acrylate, dioxane type di(meth)acrylate compound, bisphenol F type (meth)acrylate compound, dimethylol type (meth)acrylate compound, isocyanuric acid type di(meth)acrylate ... The resin may be any combination of a diol type (meth)acrylate compound, a glycol type di(meth)acrylate, a bisphenol type epoxy compound (which may contain bisphenol A, bisphenol F, bisphenol AD, or bisphenol S), a glycidylamine type epoxy compound, a naphthalene epoxy compound, a novolac epoxy compound, a siloxane-modified epoxy compound, an alicyclic epoxy compound, a biphenyl epoxy compound, a DCPD epoxy compound, a modified epoxy compound, a urethane compound containing a terminal isocyanate group, a urethane compound containing a carboxyl group, a urethane compound containing an imide ring, an organopolysiloxane-based silicon compound, a saturated or unsaturated polyester alone, or a resin in which these are mixed. In addition, various additives such as polysiloxane, fluorine-modified polysiloxane, polyacrylic, polyvinyl, and other defoamers, curing catalysts such as imidazoles and amines, antioxidants such as phenolic compounds, phosphorus compounds, and amine compounds, and phenolic resins may be blended. Using these materials increases the affinity between the underfill section 50 and the sealing section 19, improving the adhesive strength between the solar cell 20 and the electronic substrate 60.

The underfill portion 50 and the sealing portion 19 may be mixed with a light reflecting material or a strength enhancing material. In addition, the surfaces of the underfill portion 50 and the sealing portion 19 may be treated with a water repellent treatment.

As shown in FIG. 9(a), if the contact area between the negative electrode extraction electrode 21 and the positive electrode extraction electrode 22 and the electronic substrate 60 is smaller than the area of the dye-sensitized solar cell 20 in a plan view, the contact area of the underfill portion 50 with the dye-sensitized solar cell 20 becomes larger, and the connection strength between the dye-sensitized solar cell 20 and the electronic substrate 60 becomes higher.

As illustrated in FIG. 11, it is preferable that the underfill portion 50 extends to the side surface of the solar cell 20. By having the underfill portion 50 contact the side surface of the solar cell 20, external impact from the side surface can be mitigated. For example, as illustrated in FIG. 13, it is preferable that the underfill portion 50 extends to a position closer to the light-transmitting substrate 10 than the transparent electrode 11. It is preferable that the underfill portion 50 covers the entire side surface of the solar cell 20.

The underfill portion 50 may be in contact with the entire surface of the solar cell 20 facing the electronic board 60 or only a portion of it. By having the underfill portion 50 in contact with the surface of the solar cell 20 facing the electronic board 60 (positive electrode plate 17), the connection strength between the solar cell 20 and the electronic board 60 can be increased. As illustrated in FIG. 14, by preventing the underfill portion 50 from contacting the side surface of the solar cell 20, the amount of underfill portion 50 used can be reduced, and material costs can be kept down.

In the stacking direction, it is preferable that the sealing portion 19 at one or more corners is formed higher than the side surface of the solar cell 20. Specifically, as illustrated in FIG. 15, it is preferable that the sealing portion 19 at one or more corners protrudes toward the electronic board 60 from the side surface of the solar cell 20 and protrudes toward the electronic board 60 from the sealing portion 19 in other regions. In this case, the gap between the electronic board 60 and the solar cell 20 becomes larger, making it easier to fill the underfill portion 50.

As shown in FIG. 11, the sealing portion 19 extends to the surface of the positive electrode plate 17 opposite the light-transmitting substrate 10, increasing the contact area between the underfill portion 50 and the sealing portion 19 and improving the connection strength between the solar cell 20 and the electronic substrate 60.

16, there may be a bias in the extension amount of the sealing portion 19 relative to the electronic substrate 60. That is, there may be a mixture of a portion where the sealing portion 19 is connected to the electronic substrate 60 and a portion where the sealing portion 19 is not connected to the electronic substrate 60. In this case, as illustrated in FIG. 16, one or more of the four corners may be in a floating state. In other words, in a cross section of the solar cell 20 cut in the stacking direction of each layer, there may be a bias in the extension amount of the sealing portion 19, so that a part of the sealing portion 19 may be grounded to the electronic substrate 60 and a part of the sealing portion 19 different from the part of the sealing portion 19 may not be grounded to the electronic substrate 60. In such a case, if the sealing portion 19 is used to connect the solar cell 20 and the electronic substrate 60, the connection strength between the solar cell 20 and the electronic substrate 60 may be weakened against external pressure from a predetermined direction. By using the underfill portion 50 in such a structure, the connection strength between the solar cell 20 and the electronic substrate 60 can be improved.

The thickness from the surface of the positive electrode plate 17 opposite the light-transmitting substrate 10 to the surface of the light-transmitting substrate 10 opposite the positive electrode plate 17 (thickness of the solar cell 20) may be 2.5 mm or less. In this case, the solar cell 20 can be made thinner (smaller). However, the overall surface area of the solar cell 20 is reduced, and the area in which the sealing portion 19 can contact the underfill portion 50 is reduced. In this configuration, if the difference (contact angle difference) between the contact angle of the sealing portion 19 with water and the contact angle of the underfill portion 50 with water is 45° or less, the adhesion effect due to the affinity between the underfill portion 50 and the sealing portion 19 is effectively increased.

Figure 17 is a diagram illustrating the entire outer periphery α of the solar cell 20 in the cross section taken along line A-A in Figure 9(a). The shaded portion indicated by the symbol "α" does not indicate that any member is provided, but indicates the outer periphery of the solar cell 20. If the contact area between the side surface of the sealing portion 19 and the underfill portion 50 is 20% or less of the entire outer periphery α of the solar cell 20, the amount of underfill portion 50 used can be reduced, thereby reducing costs. In this configuration, if the difference (contact angle difference) between the contact angle between the sealing portion 19 and water and the contact angle between the underfill portion 50 and water is 45° or less, an adhesive effect due to the affinity between the underfill portion 50 and the sealing portion 19 can be effectively obtained.

Figure 18 is a diagram illustrating the contact area β between the surface of the sealing part 19 on the electronic board 60 side and the underfill part 50. The shaded area indicated by the symbol "β" does not indicate that any member is provided, but indicates the contact area between the surface of the sealing part 19 on the electronic board 60 side and the underfill part 50. When the difference (contact angle difference) between the contact angle between the sealing part 19 and water and the contact angle between the underfill part 50 and water is 45° or less, if the contact area β between the surface of the sealing part 19 on the electronic board 60 side and the underfill part 50 is 40% or less of the entire outer circumference α (Figure 17) of the solar cell 20 in the cross section of line A-A in Figure 9 (a), the adhesion effect due to the affinity between the underfill and the sealing part is effectively increased. Therefore, the amount of underfill part 50 used can be reduced to reduce costs, while a large adhesive strength can be achieved, resulting in cost reduction.

When the contact area between the sealing portion 19 and the underfill portion 50 is 60% or less of the entire outer circumference α of the solar cell 20 in the cross section of line A-A in Figure 9(a), the amount of underfill portion 50 used can be reduced, thereby reducing costs. In this configuration, when the difference (contact angle difference) between the contact angle between the sealing portion 19 and water and the contact angle between the underfill portion 50 and water is 45° or less, an adhesive effect due to the affinity between the underfill portion 50 and the sealing portion 19 can be effectively obtained.

As shown in FIG. 19, it is preferable that the sealing portion 19 extends around the surface of the solar cell 20 facing the electronic substrate 60, and that an underfill portion 50 is disposed between the solar cell 20 and the electronic substrate 60. In this case, the contact area between the sealing portion 19 and the underfill portion 50 increases, improving the adhesive strength between the solar cell 20 and the electronic substrate 60.

(Example)
An alcohol solution prepared from titanium alkoxide was applied to the ITO surface of a 10 mm x 10 mm x 1.1 mm glass/ITO substrate, and heated to form a reverse electron transfer prevention layer. Titanium oxide paste was printed on the ITO surface on which the reverse electron transfer prevention layer was formed by screen printing with an area of 0.98 ^cm2 . Titanium oxide paste with a large particle size was printed on top of this with an area of 1 ^cm2 . At this time, the area of a right-angled triangle measuring 2 mm long x 2 mm wide at one corner was left as an extraction electrode. The applied titanium oxide paste was heated together with the glass/ITO substrate to eliminate the organic components contained in the titanium oxide paste. The power generation layer and light reflection layer thus obtained were immersed in a dye solution to perform dye adsorption.

Separately, a pentagonal substrate was made by cutting off a right-angled triangle of 2 mm length and 2 mm width from one corner of a 10 mm x 10 mm x 100 μm (thickness) titanium substrate. Platinum was sputtered onto one surface of the pentagonal substrate to make a positive electrode plate.

Iodine, 1,3-dimethylimidazolium iodide (DMII), acetonitrile, and polyethylene oxide were mixed uniformly to form the solid electrolyte precursor. The solid electrolyte precursor was dropped onto the dye-adsorbed negative electrode power generation layer and light reflection layer, and heated to volatilize the excess acetonitrile contained in the solid electrolyte precursor.

The negative electrode, on which a power generation layer was formed by soaking the solid electrolyte, was placed opposite the platinum side of the positive electrode, and the positive and negative electrodes were stacked so that the areas of the right-angled triangles measuring 2 mm long x 2 mm wide were the same. At this time, by placing the positive and negative electrodes facing each other under reduced pressure or in a vacuum, it is possible to prevent air bubbles from being included in the solid electrolyte. In this state, ultraviolet-curing resin was applied to the side of the negative electrode glass/ITO substrate where there was no extraction electrode, and ultraviolet light was irradiated onto the side of the negative electrode and part of the surface of the positive electrode plate that did not have platinum, thereby sealing it with resin. On the other hand, for the negative electrode extraction electrode part, ultraviolet-curing resin was applied to part of the negative electrode extraction electrode part and part of the surface of the positive electrode plate that did not have platinum, and the resin was hardened and sealed by irradiating ultraviolet light.

The solar cell was fixed to the electronic board using a silver resin as a conductive adhesive, and the underfill was filled between the solar cell and the electronic board, thereby fixing the solar cell to the electronic board.

Comparative Example
In the comparative example, the solar cell was fixed to the electronic substrate only with a conductive adhesive, without using an underfill portion.

100 samples were prepared for each of the examples and comparative examples. A pressing test was performed on each sample using a high-performance digital force gauge manufactured by Imada Co., Ltd., and the presence or absence of peeling of the solar cells from the electronic substrate was confirmed among the 100 samples. If the number of samples in which peeling was confirmed was 55 or less out of the 100 samples, the sample was judged as passing (◯). If the number of samples in which peeling was confirmed was more than 55 out of the 100 samples, the sample was judged as failing (×). The results are shown in Table 1.

As shown in Table 1, the examples were judged to pass. This is believed to be because the use of the underfill section made the connection strength between the solar cell and the electronic board sufficiently high. The comparative examples were judged to fail. This is believed to be because the use of the underfill section did not make the connection strength between the solar cell and the electronic board sufficiently high.

Next, in the structure of the above example, the contact angle with water was controlled by combining various compounds for the sealing portion and underfill portion. Table 2 shows the results of a press-in test between materials with different contact angles between the sealing portion and water and the underfill portion and water. The press-in test was performed using a high-performance digital force gauge manufactured by Imada Co., Ltd.

For each contact angle difference, 100 samples were prepared. The test results were shown according to the number of samples in which peeling was observed at the interface between the sealing portion and the underfill portion. Samples in which peeling was observed in 25 or less samples were judged as good (◯), and samples in which peeling was observed in more than 25 and 55 or less samples were judged as fair (Δ). The results are shown in Table 2.

The contact angle of water was measured by dropping pure water onto the cross-section of the sealing part and the underfill part using a syringe, measuring the contact angle with water using a DM-701 type fully automatic contact angle meter manufactured by Kyowa Interface Science Co., Ltd., and determining the difference in contact angle between the sealing part and the underfill part and the water. At this time, after embedding the sample in resin, the cross-section of the sealing part and the underfill part was prepared using a 900 type Grinder/Polisher manufactured by South Bay Technology Co., Ltd. First, the sample was polished using abrasive paper of GritSize 800 [p800], 400 [p800], and 600 [p1200] manufactured by Buehler Co., Ltd., and then polished using diamond slurries of particle sizes 9, 6, 3, 1, and 0.25 μm manufactured by Hyprez Co., Ltd. as polishing powder, and then polished with colloidal silica polishing compound manufactured by Engis Japan Co., Ltd. After polishing using a cleaner manufactured by South Bay Technology, the sample was immersed in a mixed solution of 4 g of acetic acid, 10 g of hydrogen peroxide, and 26 g of ion-exchanged water to remove the colloidal silica on the surface. The GritSize of the abrasive paper and the particle size of the abrasive powder were used in the order mentioned above.

As shown in Table 2, it was confirmed that the smaller the contact angle difference, the fewer the number of peelings. If the contact angle difference was 45° or less, it was judged to be good (good). This is thought to be because the affinity between the sealing part and the underfill part increased as the contact angle difference became smaller.

Next, in the structure of the above example, for a 10 mm x 10 mm glass/ITO substrate, the area of a right-angled triangle measuring 2 mm length x 2 mm width at one corner was used as an extraction electrode, so the number of peelings was investigated when there was a bias in the extension amount of the sealing part relative to the substrate when viewed in a plane relative to the solar cell, and when there was no bias.

For the structure of the above example, the number of samples was 600. For the structure with no bias in the arrangement of the sealing portion, the number of samples was 600. A pressing test was performed using a high-performance digital force gauge manufactured by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic substrate was counted. The results are shown in Table 3. When there is no bias, the difference in the number of peeled off cases when the contact angle difference between the sealing portion and the underfill water is 45 degrees or less is 30-14=16, but when there is a bias, the difference in the number of peeled off cases is 58-24=24, which is large. Therefore, it was found that the effect of the underfill is greater and the adhesive strength is greater when there is a bias.

Next, the cases were divided into those with and without the wraparound of the sealing portion as shown in FIG. 19. Furthermore, the difference (contact angle difference) between the contact angle between the sealing portion and water and the contact angle between the underfill portion and water was divided into 0° and 46.3°. For each embodiment, the number of samples was set to 100. A pressing test was performed using a high-performance digital force gauge manufactured by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic substrate was counted. The results are shown in Table 4. As shown in Table 4, it was found that if the contact angle difference is the same, the number of peelings can be reduced when the sealing portion wraps around.

Next, for the structure of the above example, the thickness of the solar cell was changed in multiple stages (0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3 mm, 5 mm). Furthermore, cases were divided into those with and without the wraparound of the sealing part as shown in Figure 19. Furthermore, the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water was divided into 0° and 46.3°. For each embodiment, the number of samples was set to 100. The underfill part was extended to the side of the sealing part. A pressing test was performed using a high-performance digital force gauge made by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic board was counted. The results are shown in Figure 20. In Figure 20, "■" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the sealing portion wraps around, and "●" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the sealing portion does not wrap around. From the results in Figure 20, it was found that when the thickness of the solar cell is 2.5 mm or less, and the difference between the contact angle between the sealing portion and water and the contact angle between the underfill portion and water is 45° or less, the adhesion effect due to the affinity between the underfill portion and the sealing portion is effectively increased.

Next, for the structure of the above embodiment, the ratio of the contact area between the sealing part and the underfill part in the entire circumference of the solar cell in the cross section corresponding to the cross section of line A-A in Figure 9 (a) was changed in multiple stages (20%, 30%, 45%, 60%, 63%, 70%, 80%). Furthermore, the thickness of the solar cell was divided into two cases: 2.5 mm and 3 mm. Furthermore, the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water was divided into two cases: 0° and 46.3°. For each embodiment, the number of samples was set to 100. The underfill part was extended to the side of the sealing part. A pressing test was performed using a high-performance digital force gauge manufactured by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic substrate was examined. The results are shown in Figure 21. In Figure 21, "■" represents the peeling number difference obtained by subtracting the number of peelings with a contact angle difference of 0° from the number of peelings with a contact angle difference of 46.3° when the solar cell thickness is 2.5 mm, and "●" represents the peeling number difference obtained by subtracting the number of peelings with a contact angle difference of 0° from the number of peelings with a contact angle difference of 46.3° when the solar cell thickness is 3 mm. From the results in Figure 21, it was found that when the contact range between the sealing portion 19 and the underfill portion 50 is 60% or less with respect to the entire outer periphery α of the solar cell 20, and when the difference between the contact angle between the sealing portion and water and the contact angle between the underfill portion and water is 45° or less, the adhesion effect due to the affinity between the underfill portion and the sealing portion is effectively increased.

Next, for the structure of the above embodiment, the ratio of the contact area between the side of the sealing part and the underfill part in the entire circumference of the solar cell in the cross section corresponding to the cross section of line A-A in Figure 9 (a) was changed in multiple stages (5%, 10%, 13%, 18%, 21%, 27%, 31%). Furthermore, the thickness of the solar cell was divided into two cases: 2.5 mm and 3 mm. Furthermore, the case was divided into a case with and a case without the wrapping of the sealing part as shown in Figure 19. Furthermore, the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water was divided into a case of 0° and a case of 46.3°. For each embodiment, the number of samples was set to 100. The underfill part was extended to the side of the sealing part. A pressing test was performed using a high-performance digital force gauge made by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic board was examined. The results are shown in Figure 22. In Figure 22, "■" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the solar cell is 2.5 mm thick and there is no sealing portion wrapping around, "▲" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the solar cell is 3 mm thick and there is no sealing portion wrapping around, "×" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the solar cell is 2.5 mm thick and there is sealing portion wrapping around, and "●" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the solar cell is 3 mm thick and there is sealing portion wrapping around. From the results in Figure 22, it was found that if the contact area between the side of the sealing part and the underfill part is 20% or less of the entire outer periphery α of the solar cell 20, and the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water is 45° or less, the adhesive effect due to the affinity between the underfill part and the sealing part can be effectively obtained.

Next, in the structure of the above embodiment, the ratio of the contact area β (FIG. 18) between the surface of the sealing part 19 on the electronic board 60 side and the underfill part 50 to the entire outer circumference α (FIG. 17) of the solar cell 20 in the cross section of line A-A in FIG. 9(a) was changed in multiple stages (10%, 15%, 32%, 38%, 42%, 47%, 53%). Furthermore, the ratio of the contact area between the side surface of the sealing part and the underfill part in the entire outer circumference α was divided into 18% and 22%. Furthermore, the thickness of the solar cell was divided into 2.5 mm and 3 mm. Furthermore, the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water was divided into 0° and 46.3°. For each embodiment, the number of samples was 100. The underfill part was extended to the side surface of the sealing part. A pressing test was performed using a high-performance digital force gauge manufactured by Imada Co., Ltd., and the number of samples in which the solar cell peeled off from the electronic circuit board was counted. The results are shown in Figure 23. In Figure 23, "■" indicates the peeling number difference obtained by subtracting the number of peelings with a contact angle difference of 0° from the number of peelings with a contact angle difference of 46.3° when the ratio of the contact area between the side of the sealing part and the underfill part in the entire outer periphery α is 18% and the solar cell is 2.5 mm thick, and "▲" indicates the peeling number difference obtained by subtracting the number of peelings with a contact angle difference of 0° from the number of peelings with a contact angle difference of 46.3° when the ratio of the contact area between the side of the sealing part and the underfill part in the entire outer periphery α is 22% and the solar cell is 2.5 mm thick. , "x" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the ratio of the contact range between the side of the sealing part and the underfill part in the entire outer circumference α is 18% and the solar cell is 3 mm thick, and "●" represents the difference in the number of peels obtained by subtracting the number of peels with a contact angle difference of 0° from the number of peels with a contact angle difference of 46.3° when the ratio of the contact range between the side of the sealing part and the underfill part in the entire outer circumference α is 22% and the solar cell is 3 mm thick. From the results in FIG. 23, it was found that when the difference (contact angle difference) between the contact angle between the sealing part and water and the contact angle between the underfill part and water is 45° or less, the contact range β between the electronic board side surface of the sealing part and the underfill part 50 is 40% or less of the entire outer circumference α of the solar cell in the cross section of line A-A in FIG. 9(a) (FIG. 17), the adhesion effect due to the affinity between the underfill and the sealing part is effectively increased.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

REFERENCE SIGNS LIST 10 Light-transmitting substrate 10a Partial region 11 Light-transmitting electrode layer 12 Reverse electron transfer prevention layer 13 Power generation layer 13a First titanium oxide paste 13p Top surface 13q Side surface 13r End portion 14 Reflective layer 14a Second titanium oxide paste 15 Solvent 16 Solid electrolyte precursor 17 Positive electrode plate 19 Sealing portion 20 Solar cell 50 Underfill portion 60 Electronic substrate

Claims (20)

A solar cell including a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer;
a first extraction electrode provided on a surface of the first electrode layer facing the second electrode layer, in a location where the power generation layer and the second electrode layer are not provided;
a second extraction electrode provided on a surface of the second electrode layer opposite to the first electrode layer;
a substrate connected to the first extraction electrode and the second extraction electrode;
an underfill portion provided between the substrate and the solar cell;
a sealing portion that seals a side surface of the power generation layer,
the underfill portion is in contact with the sealing portion,
A solar cell module, wherein a difference between a contact angle between the sealing portion and water and a contact angle between the underfill portion and water is 8.3° or more and 46.3° or less . The solar cell module according to claim 1, characterized in that the first extraction electrode and the second extraction electrode are made of conductive resin. The solar cell module according to claim 1 or 2, characterized in that the first extraction electrode and the second extraction electrode are arranged asymmetrically in a plan view with respect to the first electrode layer. 4. The solar cell module according to claim 1, wherein a difference between a contact angle between the sealing portion and water and a contact angle between the underfill portion and water is 45° or less. 5. A solar cell module as described in any one of claims 1 to 4, characterized in that in the stacking direction of each layer of the solar cell, the sealing portion at one or more corners protrudes toward the substrate further than the side of the solar cell and protrudes toward the substrate further than the sealing portion in other regions. 6 . The solar cell module according to claim 1 , wherein the sealing portion extends onto a surface of the second electrode layer opposite to the first electrode layer. 7. The solar cell module according to claim 1, characterized in that, in a cross section of the solar cell cut in the stacking direction of each layer, there is a bias in the extension amount of the sealing portion, such that a part of the sealing portion is in contact with the substrate and a part of the sealing portion different from the part of the sealing portion is not in contact with the substrate. 8. The solar cell module according to claim 1, wherein in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the side surface of the sealing portion and the underfill portion is 20% or less of the entire outer periphery of the solar cell. 9. The solar cell module according to claim 1, characterized in that in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the substrate side surface of the sealing portion and the underfill portion is 40% or less of the entire outer periphery of the solar cell. 10. The solar cell module according to claim 1, wherein in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the sealing portion and the underfill portion is 60% or less with respect to the entire outer periphery of the solar cell. 11. The solar cell module according to claim 1, wherein the solar cell has a thickness of 2.5 mm or less. The solar cell module according to any one of claims 1 to 11, characterized in that the power generation layer is a solid. The solar cell module according to any one of claims 1 to 12, characterized in that the power generation layer is a layer having semiconductor particles carrying a dye on the surface. The solar cell module according to any one of claims 1 to 13, characterized in that the contact areas between the first and second extraction electrodes and the substrate are smaller than the area of the solar cell in a plan view. The solar cell module according to any one of claims 1 to 14, characterized in that the underfill portion extends to the side surface of the solar cell. The solar cell module according to any one of claims 1 to 15, characterized in that the underfill portion is in contact with the entire surface or a portion of the substrate side surface of the solar cell. A solar cell including a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer;
a first extraction electrode provided on a surface of the first electrode layer facing the second electrode layer, in a location where the power generation layer and the second electrode layer are not provided;
a second extraction electrode provided on a surface of the second electrode layer opposite to the first electrode layer;
a substrate connected to the first extraction electrode and the second extraction electrode;
an underfill portion provided between the substrate and the solar cell;
A solar cell module characterized in that, in a cross section of the solar cell cut in the stacking direction of each layer, there is a bias in the extension amount of the sealing portion, so that a part of the sealing portion is in contact with the substrate and a part of the sealing portion different from the part of the sealing portion is not in contact with the substrate. A solar cell including a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer;
a first extraction electrode provided on a surface of the first electrode layer facing the second electrode layer, in a location where the power generation layer and the second electrode layer are not provided;
a second extraction electrode provided on a surface of the second electrode layer opposite to the first electrode layer;
a substrate connected to the first extraction electrode and the second extraction electrode;
an underfill portion provided between the substrate and the solar cell;
A solar cell module characterized in that, in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the side surface of the sealing portion and the underfill portion is 20% or less of the entire outer periphery of the solar cell. A solar cell including a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer;
a first extraction electrode provided on a surface of the first electrode layer facing the second electrode layer, in a location where the power generation layer and the second electrode layer are not provided;
a second extraction electrode provided on a surface of the second electrode layer opposite to the first electrode layer;
a substrate connected to the first extraction electrode and the second extraction electrode;
an underfill portion provided between the substrate and the solar cell;
A solar cell module characterized in that, in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the substrate side surface of the sealing portion and the underfill portion is 40% or less of the entire outer periphery of the solar cell. A solar cell including a first electrode layer having optical transparency, a second electrode layer, and a power generation layer sandwiched between the first electrode layer and the second electrode layer;
a first extraction electrode provided on a surface of the first electrode layer facing the second electrode layer, in a location where the power generation layer and the second electrode layer are not provided;
a second extraction electrode provided on a surface of the second electrode layer opposite to the first electrode layer;
a substrate connected to the first extraction electrode and the second extraction electrode;
an underfill portion provided between the substrate and the solar cell;
A solar cell module characterized in that, in a cross section of the solar cell cut in the stacking direction of each layer, the contact area between the sealing portion and the underfill portion is 60% or less of the entire outer periphery of the solar cell.

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