Thin-film solar cell device and method for manufacturing thin-film solar cell device

Abstract

To provide a method for manufacturing a thin-film solar cell device, with which both reduction in voltage and reduction in loss can be achieved.SOLUTION: A thin-film solar cell device 10 has an integrated structure where a plurality of thin-film solar cells 20, which are divided in an integrating direction and extend in a direction intersecting with the integrating direction on a transparent substrate 12, are connected in series in the integrating direction. Each of the thin-film solar cells 20 has a first transparent electrode layer 24, a first charge transport layer 22, a photoelectric conversion layer 21, a second charge transport layer 23 and a second transparent electrode layer 25, in this order from the transparent substrate 12 side, and has a plurality of finger metal electrodes 26 between the second charge transport layer 23 and the second transparent electrode layer 25, the finger metal electrodes 26 extending in the integrating direction and being disposed to be spaced apart in a direction intersecting with the integrating direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a thin-film solar cell device and a method for manufacturing a thin-film solar cell device. [Background technology]

[0002] Patent Documents 1 and 2 disclose solar cell modules including a thin-film solar cell device. The solar cell device includes a plurality of thin-film solar cells divided in an integration direction on a transparent substrate, extending in a direction intersecting the integration direction, and connected in series and integrated. The solar cell includes, in order from the transparent substrate side, a first transparent electrode layer, a first charge transport layer, a photoelectric conversion layer, a second charge transport layer, and a second transparent electrode layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-157175 [Patent Document 2] Japanese Patent Application Publication No. 2018-157176 Summary of the Invention [Problem to be solved by the invention]

[0004] In solar cell devices with such an integrated structure, the current is high and the resistance loss in the transparent electrode layer is large, so the width of the solar cell is narrowed, which increases the number of layers in the integrated structure and increases the voltage.

[0005] Meanwhile, for example, in-vehicle solar cell devices are required to have a low voltage (for example, 55 V or less) to prevent electric shock. In this regard, in an integrated solar cell device, it is conceivable to increase the width of the solar cell, reduce the number of stages in the integrated structure, and lower the voltage. However, as mentioned above, it is expected that the resistance loss in the transparent electrode layer will increase, increasing the loss of the solar cell, and as a result, increasing the loss of the solar cell device.

[0006] An object of the present invention is to provide a thin-film solar cell device that can achieve both lower voltage and reduced loss, and a method for manufacturing the thin-film solar cell device. [Means for solving the problem]

[0007] The thin-film solar cell device of the present invention is a thin-film solar cell device having an integration structure on a transparent substrate, in which a plurality of thin-film solar cells are divided in an integration direction and extending in a direction intersecting the integration direction, and are connected in series in the integration direction, and each of the plurality of thin-film solar cells has, in order from the transparent substrate side, a first transparent electrode layer, a first charge transport layer, a photoelectric conversion layer, a second charge transport layer, and a second transparent electrode layer, and has a plurality of finger metal electrodes between the second charge transport layer and the second transparent electrode layer, and the plurality of finger metal electrodes extend in the integration direction and are arranged at a distance from each other in a direction intersecting the integration direction.

[0008] A method for manufacturing a thin-film solar cell device according to the present invention is a method for manufacturing the above-mentioned thin-film solar cell device, comprising the steps of: forming a material film for the first transparent electrode layer on the transparent substrate; forming the first separation groove and separating the material film for the first transparent electrode layer in the integration direction to form the first transparent electrode layer; forming a material film for the first charge transport layer, a material film for the photoelectric conversion layer, and a material film for the second charge transport layer in this order on the first transparent electrode layer and in the first separation groove; forming the second separation groove and separating the material film for the second charge transport layer, the material film for the photoelectric conversion layer, and the first charge transport layer in this order in the integration direction. forming the second charge transport layer, the photoelectric conversion layer, and the first charge transport layer; forming a material line pattern of the plurality of finger metal electrodes on the second charge transport layer and in the second separation groove; forming a material film of the second transparent electrode layer on the second charge transport layer and on the material line pattern of the plurality of finger metal electrodes; and forming the third separation groove and separating the material line pattern of the plurality of finger metal electrodes and the material film of the second transparent electrode layer in the integration direction to form the plurality of finger metal electrodes and the second transparent electrode layer. [Effects of the Invention]

[0009] According to the present invention, it is possible to achieve both lower voltage and reduced loss in a thin-film solar cell device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic plan view showing the solar cell device according to the present embodiment from the back surface side. [Figure 2] FIG. 2 is a cross-sectional view of the solar cell device shown in FIG. 1, taken along line II-II. [Figure 3] FIG. 2 is a cross-sectional view of the solar cell device shown in FIG. 1, taken along line III-III. [Figure 4A] FIG. 2 is a diagram showing a first transparent electrode layer material film forming step in the method for manufacturing a solar cell device according to the present embodiment. [Figure 4B] FIG. 4 is a diagram showing a step of forming a first separation groove and a first transparent electrode layer in the method for manufacturing a solar cell device according to the present embodiment. [Figure 4C] FIG. 2 is a diagram showing steps of forming a first charge transport layer material film, a photoelectric conversion layer material film, and a second charge transport layer material film in the method for manufacturing a solar cell device according to the present embodiment. [Figure 4D] FIG. 4 is a diagram showing the steps of forming a second separation groove, a first charge transport layer, a photoelectric conversion layer, and a second charge transport layer in the method for manufacturing a solar cell device according to the embodiment. [Figure 4E] FIG. 4 is a diagram showing a step of forming a finger metal electrode material line pattern and a second transparent electrode layer material film in the method for manufacturing a solar cell device according to the present embodiment. [Figure 4F] FIG. 10 is a diagram showing a step of forming a third separation groove, a finger metal electrode, and a second transparent electrode layer in the method for manufacturing a solar cell device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An example of an embodiment of the present invention will be described below with reference to the accompanying drawings. The same or equivalent parts in each drawing are designated by the same reference numerals. For convenience, hatching and reference numerals may be omitted. In such cases, reference should be made to other drawings.

[0012] (solar cell devices) Fig. 1 is a schematic plan view showing the solar cell device according to this embodiment from the back surface side, Fig. 2 is a cross-sectional view of the solar cell device shown in Fig. 1 taken along line II-II, and Fig. 3 is a cross-sectional view of the solar cell device shown in Fig. 1 taken along line III-III.

[0013] As shown in Figures 1 to 3, solar cell device 10 is a thin-film solar cell device composed of thin-film solar cells 20 made of an inorganic semiconductor thin film, an organic semiconductor thin film, or an organic-inorganic hybrid semiconductor thin film, such as an amorphous silicon-based or perovskite-based thin film. Solar cell device 10 is composed of a plurality of solar cell cells 20 divided in the X direction (integration direction) on a transparent substrate 12, extending in a Y direction (direction intersecting the integration direction) that intersects with the X direction, and connected in series for integration. Because of this integrated structure, solar cell device 10 is also called a solar cell submodule.

[0014] This shortens the conductive distance in the X direction and reduces the amount of current per cell 20, thereby reducing the resistance loss due to the electrodes 24 and 25, particularly the electrodes 24 and 25 made of transparent electrodes (ITO).

[0015] The transparent substrate 12 is, for example, a plate-shaped or film-shaped substrate. Examples of materials for the transparent substrate 12 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), and glass.

[0016] The following describes an example of a thin-film solar cell device 10 including a perovskite solar cell as the thin-film solar cell 20. The solar cell 20 has a perovskite layer 21 as a photoelectric conversion layer, charge transport layers 22 and 23, transparent electrode layers 24 and 25, and a plurality of finger metal electrodes 26.

[0017] The perovskite layer 21 is a photoelectric conversion layer that absorbs light and generates photocarriers. The compound that constitutes the perovskite crystal material is not particularly limited, but may be, for example, a compound represented by the general formula R 1 NH3M 1 X3 or HC(NH2)2M 1 X3, where R 1 is an alkyl group, preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group. 1is a divalent metal ion, preferably Pb or Sn. X is a halogen, such as F, Cl, Br, or I. All three Xs may be the same halogen element, or multiple halogens may be mixed.

[0018] A preferred example of a compound constituting a perovskite-type crystal material is a compound having the formula CH3NH3Pb(I 1-x Br x )3 (where 0≦x≦1). The spectral sensitivity characteristics of perovskite materials can be changed by changing the type and ratio of halogens. Perovskite thin films can be formed by various dry processes or solution film formation such as spin coating.

[0019] One of the charge transport layers 22 and 23 is a hole transport layer and the other is an electron transport layer. Examples of materials for the hole transport layer include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and poly(3,4-ethylenedioxythiophene) (PEDOT), fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives.

[0020] Examples of materials for the electron transport layer include metal oxides such as titanium oxide, zinc oxide, niobium oxide, zirconium oxide, and aluminum oxide.

[0021] Transparent electrode layer 24 for extracting photogenerated carriers is formed on the charge transport layer 22 side of solar cell 20. Transparent electrode layer 25 for extracting photogenerated carriers is formed on the charge transport layer 23 side of solar cell 20. Transparent electrode layers 24, 25 are preferably made of metal oxides such as ITO, zinc oxide, and tin oxide.

[0022] The plurality of finger metal electrodes 26 are disposed between the second charge transport layer 23 and the second transparent electrode layer 25. Each of the finger metal electrodes 26 extends in the X direction (accumulation direction), and the plurality of finger metal electrodes 26 are disposed at intervals in the Y direction (direction intersecting the accumulation direction). Silver, copper, aluminum, etc. are preferably used as the material for the finger metal electrodes. Alternatively, the material for the finger metal electrodes may be formed from a paste-like material containing metal particles and an acrylic or epoxy resin, etc.

[0023] Each of the solar cells 20 extends in the Y direction (a direction intersecting the integration direction) and has a first separation groove P1, a second separation groove P2, and a third separation groove P3 arranged in this order in the X direction (integration direction).

[0024] The first separation grooves P1 separate the first transparent electrode layers 24 in the X direction (accumulation direction). The first separation grooves P1 have a depth corresponding to the thickness of the first transparent electrode layers 24 in the Z direction (stacking direction), and are filled with the material of the first charge transport layer 22.

[0025] The second separation groove P2 separates the second charge transport layer 23, the photoelectric conversion layer 21, and the first charge transport layer 22 in the X direction (accumulation direction). The second separation groove P2 has a depth corresponding to the thicknesses of the second charge transport layer 23, the photoelectric conversion layer 21, and the first charge transport layer 22 in the Z direction (stacking direction). The portions of the second separation groove P2 corresponding to the finger metal electrodes 26 are filled with the material of the finger metal electrodes 26. On the other hand, the portions of the second separation groove P2 other than the portions corresponding to the finger metal electrodes 26 are filled with the material of the second transparent electrode layer 25.

[0026] The third separation groove P3 separates the second transparent electrode layer 25 and the finger metal electrodes 26 in the X direction (accumulation direction). The third separation groove P3 has a depth corresponding to the thicknesses of the second transparent electrode layer 25, the finger metal electrodes 26, the second charge transport layer 23, the photoelectric conversion layer 21, and the first charge transport layer 22 in the Z direction (stacking direction).

[0027] Each solar cell 20 has an effective region R1 and an ineffective region R2 in the X direction (accumulation direction). The effective region R1 is a region that has the photoelectric conversion layer 21 located between the first transparent electrode layer 24 and the second transparent electrode layer 25 separated by the first separation groove P1, between the third separation groove P3 and the second separation groove P2 of an adjacent solar cell 20, and from which the power generated in this photoelectric conversion layer 21 can be extracted.

[0028] On the other hand, the invalid region R2 is an area between the second separation groove P2 and the third separation groove P3, which has a photoelectric conversion layer 21 located between the first transparent electrode layer 24 and the second transparent electrode layer 25 electrically connected in the second separation groove P2, and from which the electricity generated in this photoelectric conversion layer 21 cannot be extracted.

[0029] Each of the finger metal electrodes 26 extends in the X direction (accumulation direction) from the effective region R1 to the ineffective region R2.

[0030] (Method of manufacturing a solar cell device) Hereinafter, a method for manufacturing the solar cell device 10 of this embodiment shown in FIGS. 1 to 3 will be described with reference to FIGS. 4A to 4F. FIG. 4A is a diagram illustrating a first transparent electrode layer material film formation step in the method for manufacturing a solar cell device according to this embodiment, and FIG. 4B is a diagram illustrating a first separation groove and a first transparent electrode layer formation step in the method for manufacturing a solar cell device according to this embodiment. FIG. 4C is a diagram illustrating a first charge transport layer material film, a photoelectric conversion layer material film, and a second charge transport layer material film formation step in the method for manufacturing a solar cell device according to this embodiment. FIG. 4D is a diagram illustrating a second separation groove, a first charge transport layer, a photoelectric conversion layer, and a second charge transport layer formation step in the method for manufacturing a solar cell device according to this embodiment. FIG. 4E is a diagram illustrating a finger metal electrode material line pattern and a second transparent electrode layer material film formation step in the method for manufacturing a solar cell device according to this embodiment, and FIG. 4F is a diagram illustrating a third separation groove, a finger metal electrode, and a second transparent electrode layer formation step in the method for manufacturing a solar cell device according to this embodiment. Note that FIGS. 4A to 4F correspond to the cross-sectional view of FIG. 3, i.e., the cross-sectional view taken along line III-III in FIG. 1.

[0031] 4A, a first transparent electrode layer material film 24Z is formed on a transparent substrate 12 (first transparent electrode layer material film forming step). The method for forming the first transparent electrode layer material film 24Z is not particularly limited, but examples thereof include a CVD method and a PVD method.

[0032] 4B, a first separation groove P1 is formed, and the first transparent electrode layer material film 24Z is separated in the X direction (accumulation direction) to form the first transparent electrode layer 24 (first separation groove and first transparent electrode layer forming step). The method for forming the first separation groove P1 is not particularly limited, but examples thereof include a laser method.

[0033] 4C , the first charge transport layer material film 22Z, the photoelectric conversion layer material film 21Z, and the second charge transport layer material film 23Z are formed in this order on the first transparent electrode layer 24 and in the first separation groove P1 (first charge transport layer material film, photoelectric conversion layer material film, and second charge transport layer material film formation process). The method for forming the first charge transport layer material film 22Z, the photoelectric conversion layer material film 21Z, and the second charge transport layer material film 23Z is not particularly limited, but examples thereof include a printing method and a coating method.

[0034] 4D, a second separation groove P2 is formed, and the second charge transport layer material film 23Z, the photoelectric conversion layer material film 21Z, and the first charge transport layer material film 22Z are separated in the X direction (accumulation direction) to form the second charge transport layer 23, the photoelectric conversion layer 21, and the first charge transport layer 22 (second separation groove, first charge transport layer, photoelectric conversion layer, and second charge transport layer forming step). The method for forming the second separation groove P2 is not particularly limited, but examples thereof include a laser method.

[0035] 4E, a plurality of finger metal electrode material line patterns 26Z are formed on the second charge transport layer 23 and in the second separation trench P2 (finger metal electrode material line pattern forming step). The method for forming the plurality of finger metal electrode material line patterns 26Z is not particularly limited, and the plurality of finger metal electrode material line patterns 26Z may be formed, for example, by using a printing method, a coating method, or the like. Alternatively, the plurality of finger metal electrode material films may be formed by using a CVD method, a PVD method, or the like, and then the plurality of finger metal electrode material films may be patterned using a laser, or the like, to form the plurality of finger metal electrode material line patterns 26Z.

[0036] Next, a second transparent electrode layer material film 25Z is formed on the second charge transport layer 23 and the plurality of finger metal electrode material line patterns 26Z (second transparent electrode layer material film forming step). The method for forming the second transparent electrode layer material film 25Z is not particularly limited, but examples thereof include a CVD method and a PVD method.

[0037] 4F, a third separation groove P3 is formed, and the plurality of finger metal electrode material line patterns 26Z and the second transparent electrode layer material film 25Z are separated in the X direction (accumulation direction) to form a plurality of finger metal electrodes 26 and the second transparent electrode layer 25 (third separation groove, finger metal electrode, and second transparent electrode layer forming step). The method for forming the third separation groove P3 is not particularly limited, but examples thereof include a laser method.

[0038] Through the above steps, the solar cell device 10 of this embodiment shown in FIGS. 1 to 3 is obtained.

[0039] As described above, the solar cell device 10 of this embodiment has a plurality of finger metal electrodes 26 between the second charge transport layer 23 and the second transparent electrode layer 25. The electrode configuration of the second transparent electrode layer 25 and the finger metal electrodes 26 makes it possible to reduce the resistance of the electrode on the second transparent electrode layer 25 side (for example, the back electrode) compared to an electrode configuration having only the second transparent electrode layer 25. Furthermore, it is possible to reduce the contact resistance between the finger metal electrodes 26 and the second charge transport layer 23. This makes it possible to reduce loss in the solar cell 20 even when the voltage is lowered, that is, even when the width of the solar cell 20 in the X direction (integration direction) is increased and the number of stages in the integration structure is reduced. As a result, it is possible to reduce loss in the solar cell device 10.

[0040] Here, in the solar cell 20, the ineffective region R2 is between the second separation groove P2 and the third separation groove P3, and has the photoelectric conversion layer 21 located between the first transparent electrode layer 24 and the second transparent electrode layer 25 electrically connected at the second separation groove P2, and power generated in this photoelectric conversion layer 21 cannot be extracted. Therefore, for example, in an electrode configuration including only the second transparent electrode layer 25, as shown by the arrows in Figure 2, power generated in the photoelectric conversion layer 21 in the ineffective region R2 circulates through the first transparent electrode layer 24, the second transparent electrode layer 25 filled in the second separation groove P2, and the second transparent electrode layer 25. This generates heat in the ineffective region R2 and the second separation groove P2.

[0041] In this regard, according to the solar cell device 10 of this embodiment, the multiple finger metal electrodes 26 extend in the X direction (accumulation direction) from the effective region R1 to the ineffective region R2. In the electrode configuration of the second transparent electrode layer 25 and the finger metal electrodes 26, as shown by the arrows in FIG. 3 , the power generated in the photoelectric conversion layer 21 in the ineffective region R2 circulates through the first transparent electrode layer 24, the finger metal electrodes 26 filled in the second separation grooves P2, and the finger metal electrodes 26. In the circulation path of the power generated in the photoelectric conversion layer 21 in the ineffective region R2, the multiple finger metal electrodes 26 can reduce the resistance of the electrode (back electrode) on the second transparent electrode layer 25 side. Furthermore, the contact resistance between the finger metal electrodes 26 and the second charge transport layer 23 can be reduced. This can suppress heat generation in the ineffective region R2 and the second separation grooves P2. As a result, a decrease in power generation due to heat and deterioration of the photoelectric conversion layer (e.g., a perovskite thin film) can be suppressed.

[0042] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications and variations are possible. For example, in the above-described embodiments, a thin-film solar cell device 10 having a perovskite solar cell including a perovskite layer as the photoelectric conversion layer 21 is exemplified. However, the present invention is not limited thereto and can be applied to thin-film solar cell devices having thin-film solar cells including various thin films as the photoelectric conversion layer 21. [Explanation of symbols]

[0043] 10 Solar cell devices (thin film solar cell devices) 12 Transparent base material 20 Solar cell (thin film solar cell) 21 Photoelectric conversion layer (perovskite layer) 21Z Photoelectric conversion layer material film 22 Charge transport layer (first charge transport layer) 22Z First charge transport layer material film 23 Charge transport layer (second charge transport layer) 23Z Second charge transport layer material film 24 Transparent electrode layer (first transparent electrode layer) 24Z 1st transparent electrode layer material film 25 Transparent electrode layer (second transparent electrode layer) 25Z 2nd transparent electrode layer material film 26 finger metal electrode 26Z Finger metal electrode material line pattern P1 1st separation groove P2 2nd separation groove P3 3rd separation groove R1 Effective area R2 Invalid area

Claims

1. A thin-film solar cell device having an integrated structure on a transparent substrate, in which a plurality of thin-film solar cells are divided in an integration direction and extend in a direction intersecting the integration direction, and are connected in series in the integration direction, Each of the plurality of thin-film solar cells is a first transparent electrode layer, a first charge transport layer, a photoelectric conversion layer, a second charge transport layer, and a second transparent electrode layer, in this order from the transparent substrate side; a plurality of finger metal electrodes between the second charge transport layer and the second transparent electrode layer; the plurality of finger metal electrodes extend in the integration direction and are spaced apart in a direction intersecting the integration direction; Thin-film solar cell devices.

2. each of the plurality of thin-film solar cells extends in a direction intersecting the integration direction and has a first separation groove, a second separation groove, and a third separation groove that are arranged in this order in the integration direction; the first separation groove separates the first transparent electrode layer in the integration direction; the second isolation trench separates the second charge transport layer, the photoelectric conversion layer, and the first charge transport layer in the accumulation direction; the third separation groove separates the second transparent electrode layer and the plurality of finger metal electrodes in the integration direction; the first separation trench is filled with a portion of the first charge transport layer, a part of the second separation trench is filled with a part of the plurality of finger metal electrodes; a portion of the second separation groove other than the portion is filled with a portion of the second transparent electrode layer; The thin-film solar cell device according to claim 1 .

3. Each of the plurality of thin-film solar cells has an effective area and an ineffective area in the accumulation direction, the effective region is a region between the adjacent third separation groove and the second separation groove, which includes the photoelectric conversion layer located between the first transparent electrode layer and the second transparent electrode layer separated by the first separation groove, and from which electric power generated in the photoelectric conversion layer can be extracted; the ineffective region is a region between the second separation groove and the third separation groove, which includes the photoelectric conversion layer located between the first transparent electrode layer and the second transparent electrode layer electrically connected by the second separation groove, and from which electric power generated by the photoelectric conversion layer cannot be extracted; the plurality of finger metal electrodes extend from the effective region to the ineffective region in the integration direction; The thin-film solar cell device according to claim 2 .

4. A method for producing the thin-film solar cell device according to claim 2 or 3, comprising: forming a material film of the first transparent electrode layer on the transparent substrate; forming the first separation groove and separating the material film of the first transparent electrode layer in the integration direction to form the first transparent electrode layer; forming a material film of the first charge transport layer, a material film of the photoelectric conversion layer, and a material film of the second charge transport layer in this order on the first transparent electrode layer and in the first separation groove; forming the second separation groove and separating the material film of the second charge transport layer, the material film of the photoelectric conversion layer, and the material film of the first charge transport layer in the accumulation direction to form the second charge transport layer, the photoelectric conversion layer, and the first charge transport layer; forming a material line pattern of the plurality of finger metal electrodes on the second charge transport layer and in the second isolation trench; forming a material film of the second transparent electrode layer on the second charge transport layer and on the material line pattern of the plurality of finger metal electrodes; forming the third separation groove and separating the material line patterns of the plurality of finger metal electrodes and the material film of the second transparent electrode layer in the integration direction to form the plurality of finger metal electrodes and the second transparent electrode layer; A method for manufacturing a thin-film solar cell device comprising:

5. 5. The method for manufacturing a thin-film solar cell device according to claim 4, wherein in the step of forming the material line pattern of the plurality of finger metal electrodes, the material line pattern of the plurality of finger metal electrodes is formed using a printing method or a coating method.

6. 5. The method for manufacturing a thin-film solar cell device according to claim 4, wherein in the step of forming a material line pattern of the plurality of finger metal electrodes, a material film of the plurality of finger metal electrodes is formed using a CVD method or a PVD method, and then the material film of the plurality of finger metal electrodes is patterned using a laser to form the material line pattern of the plurality of finger metal electrodes.

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