Solar power generation equipment

Abstract

To provide a solar power generation device that can easily suppress leakage current and improve yield and power generation efficiency. [Solution] A photovoltaic power generation device in which a plurality of power generation cells, each having a first electrode, a power generation unit, and a second electrode, are arranged in a straight line, wherein each power generation cell has a monolithic structure having a scribe wire P1 for insulating the first electrode, a scribe wire P2 for insulating the power generation unit, and a scribe wire P3 for insulating the second electrode, wherein the ends of the scribe wires P1 and P3 on the side of adjacent power generation cells extend into the area of ​​the adjacent power generation cell, and the ends of the scribe wire P2 do not extend outside the area of ​​one of the power generation cells.

Description

Technical Field

[0001] The present invention relates to a photovoltaic power generation device.

Background Art

[0002] Conventionally, as a solar cell, a laminate in which an N-type semiconductor layer and a P-type semiconductor layer are arranged between opposing electrodes has been actively developed, and inorganic semiconductors such as silicon are mainly used as the N-type and P-type semiconductors. However, such an inorganic solar cell has problems in that it is costly to manufacture and difficult to increase in size, and thus its range of use is limited. Therefore, in recent years, perovskite solar cells using an organic-inorganic perovskite compound having a perovskite structure with lead, tin, etc. as the central metal in the photoelectric conversion layer have attracted attention (for example, Patent Document 1, Non-Patent Document 1). Perovskite solar cells can be expected to have high photoelectric conversion efficiency and can be continuously manufactured by a printing method such as a roll-to-roll method, so that the manufacturing cost can be significantly reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Figure 1 shows a schematic cross-sectional view illustrating an example of the structure of a conventional photovoltaic power generation device. A conventional photovoltaic power generation device has a structure in which an insulating layer 2, a first electrode 3, a power generation unit 4, and a second electrode 5 are stacked in this order on a base material 1. The first electrode 3, power generation unit 4, and second electrode 5 are patterned by laser scribing or mechanical scribing, and the stacked structure of the first electrode 3, power generation unit 4, and second electrode 5, separated by the cutting line (hereinafter referred to as the scribe line) P1 of the first electrode, the scribe line P2 of the power generation unit, and the scribe line P3 of the second electrode, forms a unit cell 61 of the photovoltaic power generation device. Each unit cell 61 is connected in series by the second electrode 5 connecting to the first electrode 3 of the adjacent unit cell via P2, forming a power generation cell 6 (hereinafter, the cell structure as shown in Figure 1 is also called a monolithic structure).

[0006] Next, Figure 2 shows a schematic diagram of a conventional solar power generation device manufactured by the printing method. When a monolithic solar power generation device is manufactured by the printing method, the solar power generation device is manufactured continuously along the flow direction of the manufacturing equipment, so the scribe lines created by the scribe are parallel to the flow direction of the manufacturing equipment (hereinafter also referred to as the length direction). As a result, the unit cells 61 are arranged in the width direction (a direction perpendicular to the length direction), and the power generation cells 6 are separated by trimming lines 7, so that they are arranged in a straight line along the flow direction. In addition, in solar power generation devices manufactured by the printing method, conductive wires 8 such as copper tape are placed at both ends in the width direction, and current is drawn out so that each power generation cell 6 is in parallel by connecting the ends of the conductive wires 8.

[0007] On the other hand, in order to increase power generation efficiency, it is necessary that each power generation cell is reliably insulated from the others. Conventional photovoltaic power generation devices manufactured by printing have trimming lines in the width direction formed at both ends in the length direction of each power generation cell by scribing the first electrode and the second electrode, thereby insulating the power generation cells by making the first electrode and the second electrode discontinuous from adjacent power generation cells. However, depending on the precision of the cutting by scribing, the scribed lines may extend into adjacent power generation cells or not reach the ends of the power generation cells. If the scribed lines extend, current may be generated in the adjacent power generation cells through unintended paths, reducing power generation efficiency. If the scribed lines do not reach the ends of the power generation cells, current may flow around the unit cell. To prevent such unintended currents (hereinafter referred to as leakage currents), it is effective to design the system so that the scribed lines are long enough to reach the ends of the power generation cells, while also leaving sufficient space between power generation cells to prevent the scribed lines of adjacent power generation cells from encroaching on each other. However, increasing the spacing between power generation cells results in a larger area that does not contribute to power generation, which leads to increased costs and a decrease in power generation per unit area.

[0008] The present invention aims to provide a photovoltaic power generation device that can easily suppress leakage current and improve yield and power generation efficiency. [Means for solving the problem]

[0009] The present invention includes the following disclosures 1 to 5. The present invention will be described in detail below. [Disclosure 1] A photovoltaic power generation device in which a plurality of power generation cells, each having a first electrode, a power generation unit, and a second electrode, are arranged in a straight line, The power generation cell has a monolithic structure comprising a scribe wire P1 for insulating the first electrode, a scribe wire P2 for insulating the power generation section, and a scribe wire P3 for insulating the second electrode. The scribe lines P1 and P3 have ends on the adjacent power generation cell side that extend into the area of ​​the adjacent power generation cell. The scribe line P2 does not extend beyond the area of ​​one of the power generation cells at either end. A solar power generation device characterized by the following features. [Disclosure 2] The photovoltaic power generation apparatus according to Disclosure 1, characterized in that the distance between each of the aforementioned power generation cells is 10 μm or more and 300 mm or less. [Disclosure 3] The photovoltaic power generation apparatus according to disclosure 1 or 2, characterized in that the overhang distance of the scribe line P1 and the scribe line P3 is 10 μm or more and 100 mm or less from the edge of the power generation cell where the respective ends of the scribe line P1 and the scribe line P3 are located. [Disclosure 4] The photovoltaic power generation apparatus according to any one of disclosures 1 to 3, characterized in that both ends of the scribe wire P2 are located within 100 mm from the end of the power generation cell. [Disclosure 5] A photovoltaic power generation device according to any one of disclosures 1 to 4, characterized in that each of the power generation cells has conductive wires connecting each of the power generation cells in parallel at both ends in the width direction.

[0010] The photovoltaic power generation device of the present invention is a photovoltaic power generation device in which a plurality of power generation cells, each having a first electrode, a power generation unit, and a second electrode, are arranged in a linear fashion. Printing methods such as the roll-to-roll method allow for continuous production, significantly increasing production efficiency compared to conventional photovoltaic power generation equipment. When a photovoltaic power generation equipment is manufactured using a printing method, a long substrate is flowed onto the stage of the manufacturing equipment, and processes such as lamination and cutting of each layer are carried out sequentially, resulting in a photovoltaic power generation equipment with a structure in which multiple power generation cells are arranged in a straight line. The present invention is effective in photovoltaic power generation equipment manufactured by such printing methods. The number of power generation cells is not particularly limited as long as there are two or more, and there is no particular upper limit as power generation cells can be formed continuously when manufactured using a printing method.

[0011] The first electrode and the second electrode can be made from conventionally known conductive materials. Examples include metals such as sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al2O3 mixture, Al / LiF mixture, and gold; conductive transparent materials such as CuI, FTO (fluorine-doped tin oxide), ITO (indium tin oxide), SnO2, AZO (aluminum zinc oxide), IZO (indium zinc oxide), and GZO (gallium zinc oxide); and conductive transparent polymers. These materials may be used individually or in combination of two or more. The first electrode and the second electrode may be either the cathode or the anode.

[0012] The thickness of the first electrode and the second electrode is not particularly limited, but a preferred lower limit is 10 nm and a preferred upper limit is 1000 nm. If the thickness is 10 nm or more, resistance can be suppressed while still functioning as an electrode, and machining can be performed smoothly. If the thickness is 1000 nm or less, the first electrode and the second electrode can be machined in a good shape without cracks or fractures. A more preferred lower limit for the thickness of the first electrode and the second electrode is 50 nm and a more preferred upper limit is 500 nm.

[0013] The method for forming the above electrodes is not particularly limited and includes, for example, vapor deposition, sputtering, and ion plating.

[0014] The above-mentioned power generation unit is the part that converts sunlight into electricity, and the same photoelectric conversion material as in conventional solar power generation devices can be used for the power generation unit. In particular, because it is suitable for manufacturing by printing and has high photoelectric conversion efficiency, the photoelectric conversion material of the above-mentioned power generation unit preferably contains an organic inorganic perovskite compound represented by the general formula AMX (where A is an organic base compound and / or alkali metal, M is a lead or tin atom, and X is a halogen atom).

[0015] The above A is an organic base compound and / or an alkali metal. Specific examples of the above organic base compound include, for example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, formamidine, acetamidine, guanidine, imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, carbazole, and their ions (for example, methylammonium (CH3NH3), etc.) and phenethylammonium, etc. Among them, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, formamidine, acetamidine, and their ions and phenethylammonium are preferred, and methylamine, ethylamine, propylamine, formamidine, and their ions are more preferred. Examples of the above alkali metal include lithium, sodium, potassium, rubidium, cesium, etc.

[0016] M above is a metal atom and is a lead or tin atom. These metal atoms may be used alone or two or more of them may be used in combination.

[0017] X above is a halogen atom. Examples of the halogen atom include chlorine, bromine, iodine, sulfur, selenium, etc. These halogen atoms may be used alone or two or more of them may be used in combination. By containing halogen in the structure, the above organic-inorganic perovskite compound becomes soluble in an organic solvent, enabling its application to an inexpensive printing method, etc. Among them, since the energy band gap of the above organic-inorganic perovskite compound becomes narrow, X is preferably iodine.

[0018] The above-mentioned organic-inorganic perovskite compound preferably has a cubic crystal structure in which a metal atom M is at the body center, an organic base compound or an alkali metal A is at each vertex, and a halogen atom X is at the face center. Although the details are not clear, having the above structure allows the orientation of the octahedra in the crystal lattice to easily change. Therefore, it is presumed that the mobility of electrons in the above-mentioned organic-inorganic perovskite compound increases, and the photoelectric conversion efficiency of the solar power generation device improves.

[0019] The above-mentioned organic-inorganic perovskite compound is preferably a crystalline semiconductor. A crystalline semiconductor means a semiconductor in which an X-ray scattering intensity distribution is measured and scattering peaks can be detected. When the above-mentioned organic-inorganic perovskite compound is a crystalline semiconductor, the mobility of electrons in the above-mentioned organic-inorganic perovskite compound increases, and the photoelectric conversion efficiency of the flexible solar power generation device improves.

[0020] Also, the degree of crystallinity can be evaluated as an index of crystallization. The degree of crystallinity can be obtained by separating the scattering peak derived from the crystalline part and the halo derived from the amorphous part detected by measuring the X-ray scattering intensity distribution by fitting, obtaining the intensity integral of each, and calculating the ratio of the crystalline part in the whole. The preferable lower limit of the crystallinity of the above-mentioned organic-inorganic perovskite compound is 30%. When the crystallinity is 30% or more, the mobility of electrons in the above-mentioned organic-inorganic perovskite compound increases, and the photoelectric conversion efficiency of the solar power generation device improves. A more preferable lower limit of the crystallinity is 50%, and an even more preferable lower limit is 70%. Also, as a method for increasing the crystallinity of the above-mentioned organic-inorganic perovskite compound, for example, thermal annealing, irradiation with intense light such as a laser, plasma irradiation, etc. can be mentioned.

[0021] Within a range that does not impair the effects of the present invention, the above-mentioned power generation part may further contain an organic semiconductor or an inorganic semiconductor in addition to the above-mentioned organic-inorganic perovskite compound. Here, the organic semiconductor or the inorganic semiconductor mentioned may serve as a hole transport layer or an electron transport layer. Examples of the above-mentioned organic semiconductors include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Other examples include conductive polymers having a poly(p-phenylenevinylene) skeleton, polyvinylcarbazole skeleton, polyaniline skeleton, polyacetylene skeleton, etc. Furthermore, examples include compounds having a porphyrin skeleton such as a phthalocyanine skeleton, naphthalocyanine skeleton, pentacene skeleton, benzoporphyrin skeleton, spirobifluorene skeleton, etc., as well as carbon-containing materials such as carbon nanotubes, graphene, and fullerene, which may be surface-modified.

[0022] Examples of the inorganic semiconductors mentioned above include titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, CuSCN, Cu2O, CuI, MoO3, V2O5, WO3, MoS2, MoSe2, and Cu2S.

[0023] When the above-mentioned power generation unit includes the organic-inorganic perovskite compound and the organic semiconductor or inorganic semiconductor, it may be a laminate formed by stacking a thin film-like organic semiconductor or inorganic semiconductor portion and a thin film-like organic-inorganic perovskite compound portion, or it may be a composite film formed by combining the organic semiconductor or inorganic semiconductor portion and the organic-inorganic perovskite compound portion. A laminate is preferred in terms of ease of manufacture, while a composite film is preferred in terms of being able to improve the charge separation efficiency in the organic semiconductor or inorganic semiconductor.

[0024] The preferred lower limit and preferred upper limit of the thickness of the power generation section described above is 5 nm. If the thickness is 5 nm or more, sufficient light can be absorbed, and the photoelectric conversion efficiency will be increased. If the thickness is 5000 nm or less, the occurrence of regions where charge separation is not possible can be suppressed, which leads to an improvement in photoelectric conversion efficiency. A more preferred lower limit for the thickness is 10 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 20 nm, and an even more preferred upper limit is 500 nm.

[0025] When the power generation unit is a composite film formed by combining an organic semiconductor or inorganic semiconductor portion with an organic-inorganic perovskite compound portion, the preferred lower limit of the thickness of the composite film is 30 nm, and the preferred upper limit is 3000 nm. If the thickness is 30 nm or more, sufficient light can be absorbed, and the photoelectric conversion efficiency will be high. If the thickness is 3000 nm or less, the charge can reach the electrodes more easily, and the photoelectric conversion efficiency will be high. A more preferred lower limit of the thickness is 40 nm, a more preferred upper limit is 2000 nm, an even more preferred lower limit is 50 nm, and an even more preferred upper limit is 1000 nm.

[0026] The above-mentioned power generation unit may have an electron transport layer between the first or second electrode, which acts as the cathode, and the layer containing the photoelectric conversion material. The material of the electron transport layer is not particularly limited, and examples include N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, etc. Specifically, examples include cyano group-containing polyphenylene vinylene, boron-containing polymers, vasocuproin, vasophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, etc. In this specification, "layer" refers not only to layers with clear boundaries, but also to layers with a concentration gradient in which the contained elements gradually change. Elemental analysis of a layer can be performed, for example, by FE-TEM / EDS line analysis of a cross-section of a photovoltaic power generation device to confirm the elemental distribution of specific elements. Furthermore, in this specification, "layer" refers not only to flat, thin-film layers, but also to layers that can form complex, interwoven structures together with other layers.

[0027] The electron transport layer described above may consist only of a thin-film electron transport layer, but it is preferable to include a porous electron transport layer. In particular, when the power generation section is a composite film formed by combining an organic semiconductor or inorganic semiconductor portion with an organic-inorganic perovskite compound portion, a more complex composite film (a more intricately interwoven structure) can be obtained, and the photoelectric conversion efficiency is higher, so it is preferable that the composite film is fabricated on a porous electron transport layer.

[0028] The preferred lower limit for the thickness of the electron transport layer is 1 nm, and the preferred upper limit is 2000 nm. If the thickness is 1 nm or more, holes can be sufficiently blocked. If the thickness is 2000 nm or less, it will not be a resistance during electron transport, and the photoelectric conversion efficiency will be high. A more preferred lower limit for the thickness of the electron transport layer is 3 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 5 nm, and an even more preferred upper limit is 500 nm.

[0029] The above-mentioned power generation unit may have a hole transport layer between the first or second electrode, which acts as the anode, and the layer containing the photoelectric conversion material. The material of the hole transport layer is not particularly limited, and the hole transport layer may be made of an organic material. Examples of materials for the hole transport layer include P-type conductive polymers, P-type low molecular weight organic semiconductors, P-type metal oxides, P-type metal sulfides, surfactants, etc. Specifically, examples include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Also, examples include conductive polymers having a triphenylamine skeleton, poly(p-phenylenevinylene) skeleton, polyvinylcarbazole skeleton, polyaniline skeleton, polyacetylene skeleton, etc. Furthermore, examples include compounds having a phthalocyanine skeleton, naphthalocyanine skeleton, pentacene skeleton, benzoporphyrin skeleton or other porphyrin skeletons, spirobifluorene skeleton, etc., molybdenum sulfide, tungsten sulfide, copper sulfide, tin sulfide, etc., fluoro group-containing phosphonic acid, carbonyl group-containing phosphonic acid, CuSCN, CuI, etc.

[0030] The photovoltaic power generation device of the present invention may have a base material. The above-mentioned substrate is not particularly limited and includes, for example, a resin film made of polyimide or polyester-based heat-resistant polymer, metal foil, thin glass sheet, etc. Among these, metal foil is preferred. By using the above-mentioned metal foil, costs can be reduced compared to using heat-resistant polymers, and high-temperature processing can be performed. In other words, when the photoelectric conversion layer contains an organic-inorganic perovskite compound, even if thermal annealing (heat treatment) is performed at a temperature of 80°C or higher to impart light resistance (resistance to photodegradation) during the formation of the photoelectric conversion layer, the generation of distortion can be minimized, and high photoelectric conversion efficiency can be obtained.

[0031] The above-mentioned metal foil is not particularly limited and includes, for example, metal foils made of metals such as aluminum, titanium, copper, and gold, or alloys such as stainless steel (SUS). These may be used individually or in combination of two or more. Among these, aluminum foil is preferred. By using the above-mentioned aluminum foil, costs can be reduced compared to using other metal foils, and workability can be improved due to its flexibility.

[0032] The photovoltaic power generation device of the present invention may have an insulating layer between the substrate and the first electrode. The insulating layer is not particularly limited, and examples include an inorganic insulating layer made of aluminum oxide, silicon oxide, zinc oxide, etc., and an organic insulating layer made of epoxy resin, polyimide, etc. In particular, when the substrate is aluminum foil, it is preferable that the insulating layer is an aluminum oxide film. By using the aluminum oxide film as the insulating layer, it is possible to suppress the deterioration of the power generation section (especially the section containing organic-inorganic perovskite compounds) by moisture from the atmosphere permeating the insulating layer, compared to the case of an organic insulating layer. By using the aluminum oxide film as the insulating layer, it is possible to suppress the phenomenon of discoloration and corrosion occurring in the power generation section containing organic-inorganic perovskite compounds over time due to contact with the aluminum foil.

[0033] The thickness of the aluminum oxide film is not particularly limited, but a preferred lower limit is 0.1 μm, a preferred upper limit is 20 μm, a more preferred lower limit is 0.5 μm, and a more preferred upper limit is 10 μm. If the thickness of the aluminum oxide film is 0.5 μm or more, the aluminum oxide film can sufficiently cover the surface of the substrate, and the insulation between the substrate and the first electrode is stable. If the thickness of the aluminum oxide film is 10 μm or less, cracks are less likely to occur in the aluminum oxide film even if the substrate is bent.

[0034] When the insulating layer is an organic insulating layer, the preferred lower limit of its thickness is 0.1 μm, and the preferred upper limit is 10 μm. A thickness of 0.1 μm or more of the organic insulating layer ensures reliable insulation between the substrate and the electrode. A thickness of 10 μm or less of the organic insulating layer allows for a highly flexible solar power generation device. A more preferred lower limit of the thickness of the organic insulating layer is 1 μm, and a more preferred upper limit is 7 μm.

[0035] The photovoltaic power generation device of the present invention may have a barrier layer covering the second electrode. The material of the barrier layer described above is not particularly limited as long as it has barrier properties, but examples include thermosetting resins, thermoplastic resins, or inorganic materials. The material of the barrier layer may also be a combination of the thermosetting resin or thermoplastic resin and the inorganic material described above.

[0036] Examples of the thermosetting resin or thermoplastic resin mentioned above include epoxy resin, acrylic resin, silicone resin, phenolic resin, melamine resin, urea resin, butyl rubber, polyester, polyurethane, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyvinyl acetate, ABS resin, polybutadiene, polyamide, polycarbonate, polyimide, and polyisobutylene.

[0037] When the barrier layer material is a thermosetting resin or a thermoplastic resin, the preferred lower limit of the barrier layer (resin layer) is 100 nm, and the preferred upper limit is 100,000 nm. A more preferred lower limit of the above thickness is 500 nm, a more preferred upper limit is 50,000 nm, an even more preferred lower limit is 1,000 nm, and an even more preferred upper limit is 20,000 nm.

[0038] Examples of the inorganic materials mentioned above include oxides, nitrides, or oxynitrides of Si, Al, Zn, Sn, In, Ti, Mg, Zr, Ni, Ta, W, Cu, or alloys containing two or more of these elements. In particular, oxides, nitrides, or oxynitrides of metallic elements containing both Zn and Sn are preferred in order to impart water vapor barrier properties and flexibility to the barrier layer.

[0039] When the barrier layer material is an inorganic material, the preferred lower limit of the barrier layer (inorganic layer) is 30 nm, and the preferred upper limit is 3000 nm. If the thickness is 30 nm or more, the inorganic layer can have sufficient water vapor barrier properties, improving the durability of the photovoltaic power generation device. If the thickness is 3000 nm or less, even if the thickness of the inorganic layer increases, the stress generated is small, so delamination between the inorganic layer and the laminate can be suppressed. A more preferred lower limit of the thickness is 50 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 100 nm, and an even more preferred upper limit is 500 nm. The thickness of the inorganic layer can be measured using an optical interferometry film thickness measuring device (for example, the FE-3000 manufactured by Otsuka Electronics Co., Ltd.).

[0040] The photovoltaic power generation device of the present invention may further have the barrier layer covered with other materials, such as a resin film or a resin film coated with an inorganic material. That is, the barrier layer may be used to seal, fill, or bond the space between the laminate and the other material. This allows for sufficient blocking of water vapor even if there are pinholes in the barrier layer, thereby further improving the durability of the photovoltaic power generation device.

[0041] The above-mentioned power generation cell has a monolithic structure comprising a scribe wire P1 that insulates the first electrode, a scribe wire P2 that insulates the power generation section, and a scribe wire P3 that insulates the second electrode (hereinafter, the scribe wires P1 to P3 will also be simply referred to as P1 to P3). The structure of the above-mentioned power generation cell is the same monolithic structure as conventional photovoltaic power generation equipment, as shown in Figure 1. By making each power generation cell a monolithic structure, several advantages can be obtained, such as the ability to create a highly dense integrated structure, to increase the voltage while keeping the current value low, and to reduce Joule heat loss.

[0042] The ends of the above-mentioned scribe lines P1 and P3 on the adjacent power generation cell side extend into the area of ​​the adjacent power generation cell, while the ends of the above-mentioned scribe line P2 do not extend outside the area of ​​one of the power generation cells. Here, Figure 3 shows a schematic diagram representing the periphery between power generation cells in a photovoltaic power generation device manufactured by a conventional printing method, and Figure 4 shows a schematic diagram representing the periphery between power generation cells in the photovoltaic power generation device of the present invention. In photovoltaic power generation devices manufactured by a conventional printing method, depending on the accuracy of the scribe, P1 to P3 may not reach the end of the power generation cell, or P1 to P3 may extend into the adjacent power generation cell. For example, as shown in Figure 3A, if the scribe lines, especially P1 and P2, do not reach the end of the power generation cell 6, the current generated in the power generation section will flow around P1 or P3, bypassing the intended path. Also, as shown in Figure 3B, if the current extends into the adjacent power generation cell 6, especially if P2 extends into the adjacent power generation cell 6, an unintended connection point between the first and second electrodes is created within the adjacent power generation cell 6, and a current that passes through the connection point but not through the power generation section is generated around the connection point. When such leakage current occurs, the voltage and current cannot be obtained as designed, resulting in a decrease in power generation efficiency. Furthermore, in conventional photovoltaic power generation equipment manufactured using printing methods, the spacing between power generation cells was increased and the scribe lines were lengthened to suppress leakage current, thereby compensating for the shortage of scribe lines and preventing overflow onto adjacent power generation cells. However, increasing the spacing between power generation cells worsened both cost and power generation efficiency per module area.

[0043] In the photovoltaic power generation device of the present invention, as shown in Figure 4, the ends of the scribe lines P1 of the first electrode and P3 of the second electrode that are adjacent to the adjacent power generation cell 6 are extended into the area of ​​the adjacent power generation cell 6, thereby preventing current from bypassing within the power generation cell 6. On the other hand, by ensuring that both ends of the scribe line P2 of the power generation unit 4 do not extend outside the area of ​​the power generation cell 6, the second electrode and the first electrode in the adjacent power generation cell 6 are not unintentionally connected, thereby suppressing leakage current within the adjacent power generation cell 6. As a result, the number of defective unit cells 61 and power generation cells 6 is reduced, improving the yield. Furthermore, even if the ends of P1 and P3 extend to the adjacent power generation cell to some extent, it does not significantly affect the performance of the adjacent power generation cell, and even if the end of P2 is somewhat far from the edge of the power generation cell, it does not significantly affect the power generation performance. Therefore, with the above structure, even if the accuracy of the scribe is not high, it is not necessary to leave space between the power generation cells 6, which reduces costs and increases the amount of power generated per unit area, thereby improving power generation efficiency. In this specification, trimming lines are not included in the region of a power generation cell. Also, if the target power generation cell has power generation cells on both sides, both ends of P1 and P3 extend into the region of the adjacent power generation cell. On the other hand, if the target power generation cell is at either end of a linear arrangement of power generation cells, there is only one adjacent power generation cell, so only one end of P1 and P3 extends into the region of the adjacent power generation cell, while the other end extends beyond the trimming line.

[0044] The distance between each of the above-mentioned power generation cells is preferably between 10 μm and 300 mm. As described above, the photovoltaic power generation device of the present invention does not require a large spacing between power generation cells, so by setting the distance between power generation cells within the above range, it is possible to further reduce costs while increasing power generation efficiency. The distance between each power generation cell is more preferably 20 mm or less, and even more preferably 2 mm or less. Here, the distance between power generation cells refers to the shortest distance between trimming lines (non-power generation portions that do not contribute to power generation), including the width of the trimming line. Also, if two power generation cells are separated by one trimming line, the distance between power generation cells is the width of the trimming line.

[0045] The overhang distance of the above-mentioned scribe lines P1 and P3 is between 10 μm and 100 mm from the edge of the power generation cell where the ends of the above-mentioned scribe lines P1 and P3 are located. By setting the overhang distance of P1 and P3 within the above range, the impact on the power generation of adjacent power generation cells can be further suppressed. The overhang distance of P1 and P3 is more preferably 50 mm or less, and even more preferably 20 mm or less. Here, the end of the power generation cell refers to the point on the end of the power generation cell that intersects with the target P1 or P3.

[0046] Preferably, the positions of both ends of the above-mentioned scribe line P2 are within 100 mm from the ends in the longitudinal direction of the power generation cell. By positioning both ends of P2 within 100 mm from the longitudinal ends of the power generation cell, it is possible to minimize the impact on the power generation efficiency of the power generation cell while making it less likely for P2 to extend outside the power generation cell's area. It is more preferable that the positions of both ends of P2 be within 50 mm from the longitudinal ends of the power generation cell, and even more preferable that be within 10 mm. Here, the longitudinal ends of the power generation cell refer to the ends that lie on the extension of P2, with the ends of the power generation cell closest to each end of P2 being used as reference points.

[0047] The photovoltaic power generation device of the present invention preferably has conductive wires connecting each of the power generation cells in parallel at both ends in the width direction of each power generation cell. By connecting each power generation cell in parallel with conductive wires, a current of a constant voltage can be obtained. Methods for connecting these conductive wires include, for example, attaching conductive wires such as copper tape across the widthwise ends of each power generation cell, as shown in Figure 2, or arranging conductive wires across the widthwise ends of each power generation cell and then connecting each wire with other conductive wires. Among these, the method of attaching conductive wires across the widthwise ends of each power generation cell is preferred because it has a simple structure and is easy to connect.

[0048] The method for manufacturing the photovoltaic power generation device of the present invention is not particularly limited, and conventionally known methods can be used. For example, a method can be described as having the steps of: laminating the electrodes on the substrate to form P1 and trimming lines; laminating the power generation section on the electrodes to form P2; and laminating the second electrode on the power generation section to form P3 and trimming lines. In this case, by adjusting the start and end timings of cutting P1 to P3, it is possible to create a structure in which P1 and P3 extend into the area of ​​the adjacent power generation cell, while P2 does not extend outside the area of ​​the power generation cell. Furthermore, if the photovoltaic power generation device of the present invention has conductive wires, after forming P3, a step is performed to connect the ends of each power generation cell in the width direction with conductive wires so that the power generation cells are in parallel. [Effects of the Invention]

[0049] According to the present invention, it is possible to provide a photovoltaic power generation device that can easily suppress leakage current and improve yield and power generation efficiency. [Brief explanation of the drawing]

[0050] [Figure 1] This is a schematic cross-sectional view illustrating an example of the structure of a conventional solar power generation system. [Figure 2] This is a schematic diagram representing a conventional solar power generation device manufactured using printing technology. [Figure 3A] This is a schematic diagram showing the periphery between power generation cells in a conventional solar power generation system manufactured using a printing method. [Figure 3B] This is a schematic diagram showing the periphery between power generation cells in a conventional solar power generation system manufactured using a printing method. [Figure 4] This is a schematic diagram showing the periphery between power generation cells in the photovoltaic power generation device of the present invention. [Figure 5A] This is a photograph of the EL inspection of cell 1 in Experimental Example 1. [Figure 5B] This is a photograph of the EL inspection of cell 2 in Experimental Example 1. [Modes for carrying out the invention]

[0051] The embodiments of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0052] (Experimental Example 1) (1) Manufacturing of solar power generation equipment

[0053] First, a pattern of P1 scribe lines was formed on a polyethylene terephthalate (PET) film with an ITO film already deposited as the first electrode, using a patterning machine. The patterning was done so that two monolithic power generation cells, each consisting of six unit cells connected in series, were adjacent to each other. Furthermore, a 500 μm wide first trimming line was formed between adjacent power generation cells parallel to the direction of current flow (width direction) for insulation. Each power generation cell was then independently divided into six unit cells by placing seven P1 scribe lines at 5 mm intervals perpendicular to the first trimming line (length direction). The scribe conditions for the P1 scribe lines formed on one of the power generation cells (hereinafter referred to as cell 1) were set so that the scribe lines extended 15 mm into the area of ​​the adjacent power generation cell (hereinafter referred to as cell 2). Similarly, the scribe conditions for the P1 scribe lines formed on cell 2 were set so that the scribe lines extended 15 mm into the area of ​​cell 1.

[0054] Next, a thin-film electron transport layer with a thickness of 20 nm was formed on the scribed first electrode by sputtering. Furthermore, a titanium dioxide paste containing titanium dioxide was applied to the thin-film electron transport layer by spin coating and dried to form a porous electron transport layer with a thickness of 100 nm. Next, lead iodide was dissolved as a metal halide compound in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to prepare a 1 M solution, which was then deposited on the porous electron transport layer by spin coating. Furthermore, methylammonium iodide was dissolved as an amine compound in 2-propanol to prepare an 8 wt% solution. This solution was applied to the lead iodide by spin coating and annealed at 150°C for 10 minutes to form a photoelectric conversion layer containing the organic-inorganic perovskite compound CH3NH3PbI3 with a thickness of 700 nm. Next, a chlorobenzene solution containing 2% by weight of Spiro-OMETAD (manufactured by Merck) was applied to the photoelectric conversion layer by spin coating and then dried to form a hole transport layer with a thickness of 80 nm, thereby forming a power generation unit consisting of an electron transport layer, a photoelectric conversion layer, and a hole transport layer.

[0055] Next, by scribing the formed power generation layer, a pattern of six P2 scribe lines was created in both cell 1 and cell 2. In this process, the P2 lines formed in cell 1 were designed so that their ends extended 15 mm into the area of ​​cell 2. The P2 lines formed in cell 2 were designed so that both ends were positioned 5 mm inward from the edges of cell 2, so that the P2 lines did not extend outside the area of ​​cell 2.

[0056] After forming the P2 scribe lines, a 100 nm thick Al film was formed as a second electrode by sputtering. Subsequently, the formed second electrode was scribed to create a pattern of six P3 scribe lines in both cell 1 and cell 2. In this process, the scribe conditions were set so that the P3 lines formed in cell 1 extended 15 mm into the area of ​​cell 2. Similarly, the scribe conditions were set so that the P3 lines formed in cell 2 extended 15 mm into the area of ​​cell 1.

[0057] After forming P3, a second trimming line with a cutting width of 500 μm was drawn parallel to the width direction on the first trimming line, penetrating the second electrode, thereby forming cells 1 and 2 with a spacing of 500 μm between them. Subsequently, the positive electrodes and negative electrodes of cells 1 and 2 were connected with copper tape at their widthwise ends, and cells 1 and 2 were connected in parallel to obtain a photovoltaic power generation device.

[0058] (EL inspection) The obtained photovoltaic power generation device was subjected to electroluminescence (EL) testing using an EL testing device (PVX330, manufactured by AITES). Photographs of the EL testing are shown in Figures 5A and 5B. Figure 5A is a photograph of cell 1, and Figure 5B is a photograph of cell 2. White areas indicate where electricity is flowing, and black areas indicate where electricity is not flowing. In cell 1, which does not meet the scribe line conditions of the present invention, P2 extends into cell 2, resulting in a lower power generation rate for cell 2 (larger black area), as shown in Figure 5B. On the other hand, in cell 2, which meets the scribe line conditions of the present invention, P2 does not extend beyond cell 2, thus not affecting the power generation performance of the adjacent cell 1, resulting in a higher power generation rate for cell 1 (larger white area), as shown in Figure 5A. Furthermore, image processing was performed based on the obtained EL testing photographs to calculate the ratio of the area where current is flowing in cell 1 and the ratio of the area where current is flowing in cell 2. The results were 91.6% for cell 1 and 34.7% for cell 2. [Industrial applicability]

[0059] According to the present invention, it is possible to provide a photovoltaic power generation device that can easily suppress leakage current and improve yield and power generation efficiency. [Explanation of Symbols]

[0060] 1 Base material 2. Insulating layer 3 electrodes 4. Photoelectric conversion layer 5 Second electrode 6 power cells 61 unit cells 7. Trimming lines 8 Conductive wires

Claims

1. A photovoltaic power generation device in which a plurality of power generation cells, each having a first electrode, a power generation unit, and a second electrode, are arranged in a straight line, The power generation cell has a monolithic structure comprising a scribe wire P1 for insulating the first electrode, a scribe wire P2 for insulating the power generation section, and a scribe wire P3 for insulating the second electrode. The scribe lines P1 and P3 have ends on the adjacent power generation cell side that extend into the area of ​​the adjacent power generation cell. The scribe line P2 does not extend beyond the area of ​​one of the power generation cells at either end. A solar power generation device characterized by the following features.

2. The photovoltaic power generation apparatus according to claim 1, characterized in that the distance between each of the aforementioned power generation cells is 10 μm or more and 300 mm or less.

3. The photovoltaic power generation apparatus according to claim 1 or 2, characterized in that the overhang distance of the scribe line P1 and the scribe line P3 is 10 μm or more and 100 mm or less from the edge of the power generation cell where the respective ends of the scribe line P1 and the scribe line P3 are located.

4. The photovoltaic power generation apparatus according to claim 1 or 2, characterized in that the positions of both ends of the scribe line P2 are within 100 mm from the ends in the longitudinal direction of the power generation cell.

5. The photovoltaic power generation apparatus according to claim 1 or 2, characterized in that each of the power generation cells has conductive wires connecting each of the power generation cells in parallel at both ends in the width direction.

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