Solar cell module

Abstract

The present invention provides a solar cell module that can prevent moisture from entering from the sides of the photoelectric conversion layer. [Solution] The solar cell module 1 comprises a light-transmitting substrate 11, a first electrode 12, a first carrier transport layer 13, a photoelectric conversion layer 14, a second carrier transport layer 15, a buffer layer 16, and a second electrode 17 in this order. The substrate 11 has a recess 110 having a bottom wall portion 111 that extends along the plane of the photoelectric conversion layer 14 and covers the first electrode 12, and a side wall portion 112 that extends along the thickness direction of the photoelectric conversion layer 14. The side wall portion 112 is formed to cover at least the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, and the side surface of the photoelectric conversion layer 14.

Description

Technical Field

[0001] The present invention relates to a solar cell module.

Background Art

[0002] Conventionally, as such a technical field, there is one described in, for example, Patent Document 1. The solar cell module described in Patent Document 1 includes a substrate, a first electrode provided on the substrate, a photoelectric conversion layer provided on the first electrode, a second electrode provided on the photoelectric conversion layer, and a barrier layer provided so as to cover a side portion of the photoelectric conversion layer. In this solar cell module, the barrier layer composed of a dense inorganic material layer is used as a moisture-proof layer, which prevents moisture from entering from the side surface of the photoelectric conversion layer and prevents deterioration of the solar cell due to moisture.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the above-described solar cell module, since the barrier layer corresponding to the moisture-proof layer is discontinuous and interrupted at the end portion, there is a problem that moisture is allowed to enter through the corresponding discontinuous portion.

[0005] The present invention has been made to solve such technical problems, and an object thereof is to provide a solar cell module capable of preventing moisture from entering from the side surface of a photoelectric conversion layer.

Means for Solving the Problem

[0006] The solar cell module according to the present invention comprises, in this order, a light-transmitting substrate, a first electrode, a photoelectric conversion layer containing a perovskite compound, and a second electrode, wherein the substrate has a recess having a bottom wall portion extending along the plane of the photoelectric conversion layer and covering the first electrode, and a side wall portion extending along the thickness direction of the photoelectric conversion layer, and the side wall portion is formed to cover at least the side surface of the first electrode and the side surface of the photoelectric conversion layer.

[0007] In the solar cell module according to the present invention, the substrate has a recess having a bottom wall portion that extends along the plane of the photoelectric conversion layer and covers the first electrode, and a side wall portion that extends along the thickness direction of the photoelectric conversion layer. The side wall portion of the substrate is formed to cover at least the side surface of the first electrode and the side surface of the photoelectric conversion layer. By covering the side surface of the photoelectric conversion layer with the side wall portion of the substrate in this way, it is possible to prevent moisture from entering from the side surface of the photoelectric conversion layer. As a result, it is possible to suppress the deterioration of the photoelectric conversion layer caused by moisture intrusion and prevent a decrease in the power generation efficiency of the solar cell module.

[0008] In the solar cell module according to the present invention, it is preferable that a moisture-proof layer made of oxide is provided on the inside of the side wall portion, of which the inside of the bottom wall portion and the inside of the side wall portion are located. In this way, in addition to preventing moisture intrusion by the side wall portion of the substrate, moisture intrusion can also be prevented by the moisture-proof layer provided on the inside of the side wall portion. Thus, the cooperation of the side wall portion and the moisture-proof layer can further enhance the effect of preventing moisture intrusion from the side of the photoelectric conversion layer.

[0009] In the solar cell module according to the present invention, it is preferable that the side wall portion is inclined such that the space of the recess widens as it moves from the bottom wall portion toward the opening side of the recess. In this way, a moisture-proof layer can be easily formed on the inside of the side wall portion, thereby improving the film-forming ability of the moisture-proof layer. [Effects of the Invention]

[0010] According to the present invention, it is possible to prevent moisture from entering from the side of the photoelectric conversion layer. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing a solar cell module according to the first embodiment. [Figure 2] This is a schematic diagram illustrating the manufacturing process of a substrate with a recess. [Figure 3] This is a schematic cross-sectional view showing a solar cell module according to the second embodiment. [Figure 4] This is a schematic diagram illustrating the manufacturing of a substrate with recesses and the formation of a moisture-proof layer. [Figure 5] This is a schematic cross-sectional view showing a solar cell module according to the third embodiment. [Figure 6] This is a schematic diagram illustrating the manufacturing of a substrate with recesses and the formation of a moisture-proof layer. [Modes for carrying out the invention]

[0012] Embodiments of the solar cell module according to the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. In the following description, unless otherwise specified, "side surface" refers to the end surface along the direction of light incidence (in other words, the end surface parallel to the direction of light incidence) assuming that light is incident perpendicularly on the solar cell module. Also, "moisture" includes water and water vapor. Furthermore, "thickness" as referred to in the following description refers to the distance in the direction of light incidence.

[0013] [First Embodiment] Figure 1 is a schematic cross-sectional view showing a solar cell module according to the first embodiment. The solar cell module 1 of this embodiment is, for example, a thin plate-shaped perovskite solar cell and has a plurality of cells 10 arranged in parallel along one direction (for example, the longitudinal direction) of the solar cell module 1.

[0014] As shown in Figure 1, the solar cell module 1 of this embodiment comprises a substrate 11, a first electrode 12, a first carrier transport layer 13, a photoelectric conversion layer 14, a second carrier transport layer 15, a buffer layer 16, and a second electrode 17. The first electrode 12, the first carrier transport layer 13, the photoelectric conversion layer 14, the second carrier transport layer 15, the buffer layer 16, and the second electrode 17 are stacked on the substrate 11 in this order.

[0015] The substrate 11 is a light-transmitting insulating substrate, formed from, for example, glass or resin. The substrate 11 is patterned for series connection. Examples of light-transmitting resins include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamide-imide, or cycloolefin polymer. The substrate 11 may also be a flexible sheet or film. As will be described later, the substrate 11 of this embodiment has a recess 110 having a bottom wall portion 111 and a side wall portion 112. The thickness of the bottom wall portion 111 is, for example, about 0.1 mm.

[0016] The first electrode 12 is a positive electrode that collects holes and is formed of a transparent conductive oxide (TCO) that has conductivity and light transmittance. Examples of transparent conductive oxides include indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof. Among these, indium-based composite oxides mainly composed of indium oxide are preferred from the viewpoint of high conductivity and transparency, and elements such as Sn, W, Zn, and Ti may be further added as dopants. In this embodiment, the first electrode 12 is made of a translucent metal oxide material such as ITO (Indium Tin Oxide), and its thickness is, for example, about 150 nm.

[0017] The first carrier transport layer 13 is, for example, a hole transport layer, and its thickness is, for example, about 2 nm. As the hole transport layer, known organic materials or inorganic materials that can be used for hole transport layers can be employed. Examples of the organic material include 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), polyethylenedioxythiophene:polystyrene sulfonic acid (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and the like. Examples of the inorganic material include nickel oxide, copper oxide, and the like.

[0018] The photoelectric conversion layer 14 is a flat layer containing a perovskite compound, and its thickness is, for example, about 550 nm. That is, the photoelectric conversion layer 14 is a layer capable of converting irradiated light energy into electrical energy, absorbing light received by the solar cell module 1 and converting it into free electrons and holes. In the present embodiment, the photoelectric conversion layer 14 is a perovskite layer whose main material is a compound having a perovskite-type crystal structure. Examples of this compound include methylammonium lead halide, methylammonium lead iodide and the like, or part of the halogen atoms may contain bromine atoms or chlorine atoms.

[0019] The second carrier transport layer 15 is, for example, an electron transport layer, and its thickness is, for example, about 40 nm. As the electron transport layer, known organic materials or inorganic materials that can be used for electron transport layers can be employed. Examples of the organic material include fullerene compounds, phenanthroline derivatives, polyethyleneimines, and the like. Examples of the inorganic material include titanium oxide, tin oxide, zinc oxide, and the like.

[0020] The buffer layer 16 is a layer for improving photoelectric conversion efficiency, and is formed of, for example, an organic semiconductor. The thickness of the buffer layer 16 is, for example, about 30 nm. Note that this buffer layer 16 is not necessarily required and may be omitted.

[0021] The second electrode 17 is an electrode that pairs with the first electrode 12, and in this embodiment, it is the negative electrode. The second electrode 17 may be made of the same material as the first electrode 12, but unlike the first electrode 12, it does not have to be light-transmitting. In this embodiment, the second electrode 17 is formed of IZO (Indium Zinc Oxide), and its thickness is, for example, about 200 nm.

[0022] In a solar cell module 1 having this structure, when light such as sunlight is irradiated from the substrate 11 side, the light passes through the substrate 11, the first electrode 12, and the first carrier transport layer 13 because they are light-transmitting, and reaches the photoelectric conversion layer 14. The light that reaches the photoelectric conversion layer 14 is absorbed by the photoelectric conversion layer 14 if it is of a specific wavelength. The absorbed light is converted into multiple holes and free electrons. The converted holes and free electrons move to the first carrier transport layer (hole transport layer) 13 and the second carrier transport layer (electron transport layer) 15, respectively, and are then collected by the first electrode 12 and the second electrode 17. As a result, the solar cell module 1 generates electricity.

[0023] Furthermore, the solar cell module 1 of this embodiment is equipped with a moisture-proof layer 20 to prevent the intrusion of moisture. The moisture-proof layer 20 is formed of a metal oxide or an inorganic oxide (for example, Al2O3, TiO2, ZnO, SnO2). In this embodiment, the moisture-proof layer 20 is a dense inorganic material layer (high density of inorganic material) and is formed to cover the second electrode 17, as well as the sides of the second electrode 17, the sides of the buffer layer 16, the sides of the second carrier transport layer 15, the sides of the photoelectric conversion layer 14, and the sides of the first carrier transport layer 13. The thickness of the moisture-proof layer 20 is, for example, 40 nm or less.

[0024] Furthermore, when the moisture barrier layer 20 is formed from a dense inorganic material layer, it can perform a moisture barrier function and suppress the deterioration of the moisture barrier effect caused by ultraviolet rays, temperature changes, etc. The moisture barrier layer 20 is formed by methods such as atomic layer deposition, sputtering, and vacuum deposition.

[0025] Furthermore, it is preferable that the moisture barrier layer 20 has gas barrier and insulating properties. In addition, the moisture barrier layer 20 may or may not be light-transmitting.

[0026] As shown in Figure 1, the solar cell module 1 is evenly divided into multiple cells 10 by multiple dividing grooves 22. The multiple cells 10 are arranged side by side along the longitudinal direction of the solar cell module 1 and are also connected in series. Furthermore, as shown in Figure 1, hole extraction electrodes 18 and electron extraction electrodes 19 are provided at both ends of the solar cell module 1 in the longitudinal direction.

[0027] In the solar cell module 1, as shown by the arrows in Figure 1, electrons enter the first electrode 12 from the hole extraction electrode 18, pass through the first carrier transport layer 13, the photoelectric conversion layer 14, the second carrier transport layer 15, the buffer layer 16, and the second electrode 17, and then flow to the first electrode 12 of the adjacent cell 10 via the inter-cell conduction section 23. In this way, the electrons pass through multiple cells 10 and are finally extracted from the electron extraction electrode 19.

[0028] Furthermore, in this embodiment, the substrate 11 has a recess 110 having a bottom wall portion 111 that extends along the plane of the photoelectric conversion layer 14 (i.e., the longitudinal direction of the solar cell module 1) and covers the first electrode 12, and a side wall portion 112 that extends along the thickness direction of the photoelectric conversion layer 14 (i.e., the direction of light incidence). As shown in Figure 2, which will be described later, the bottom wall portion 111 has a rectangular shape, and the side wall portion 112 is formed along the four sides of the bottom wall portion 111 so as to surround the bottom wall portion 111.

[0029] The side wall portion 112 is formed to cover the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, the side surface of the photoelectric conversion layer 14, the side surface of the second carrier transport layer 15, the side surface of the buffer layer 16, and the side surface of the second electrode 17. The leading edge of the side wall portion 112 in the direction of light incidence is covered by the moisture-proof layer 20 described above.

[0030] The manufacturing method for the solar cell module 1 configured as described above includes, for example, a recess preparation step and a lamination step. In the recess preparation step, as shown in Figure 2, first a flat substrate 200 is prepared (see Figure 2(a)). Next, the flat substrate 200 is processed to form a recess 110 having a bottom wall portion 111 and a side wall portion 112 (see Figure 2(b)). After that, patterning is applied to the bottom wall portion 111 and the side wall portion 112 for series connection.

[0031] In the lamination process, the first electrode 12, the first carrier transport layer 13, the photoelectric conversion layer 14, the second carrier transport layer 15, the buffer layer 16, and the second electrode 17 are sequentially deposited and laminated on the bottom wall portion 111 of the substrate 11. The deposition methods for each electrode and each layer can be those already known, and a detailed explanation is omitted here.

[0032] Next, a moisture-proof layer 20 made of an oxide (e.g., Al2O3) is deposited on the buffer layer 16 stacked on the bottom wall portion 111 and on the leading surface of the side wall portion 112, for example, using atomic layer deposition (ALD). This completes the manufacturing of the solar cell module 1.

[0033] In the solar cell module 1 according to this embodiment, the substrate 11 has a recess 110 having a bottom wall portion 111 that extends along the longitudinal direction of the solar cell module 1 and covers the first electrode 12, and a side wall portion 112 that extends along the direction of light incidence. The side wall portion 112 is formed to cover the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, the side surface of the photoelectric conversion layer 14, the side surface of the second carrier transport layer 15, the side surface of the buffer layer 16, and the side surface of the second electrode 17. By covering the side surface of the photoelectric conversion layer 14 with the side wall portion 112 of the substrate 11 in this way, moisture intrusion from the side surface of the photoelectric conversion layer 14 can be prevented. As a result, deterioration of the photoelectric conversion layer 14 caused by moisture intrusion can be suppressed, and a decrease in the power generation efficiency of the solar cell module 1 can be prevented.

[0034] [Second Embodiment] A second embodiment of the solar cell module will be described below with reference to Figure 3. The solar cell module 1A of this embodiment differs from the first embodiment described above in that a moisture-proof layer 21 is formed on the inside of the bottom wall portion 111 and the inside of the side wall portion 112 of the substrate 11. The other structures are the same as those of the first embodiment, so a redundant explanation will be omitted.

[0035] Figure 3 is a schematic cross-sectional view showing a solar cell module according to the second embodiment. As shown in Figure 3, in the solar cell module 1A of this embodiment, a moisture-proof layer 21 is formed on the inside of the bottom wall portion 111 and the inside of the side wall portion 112 of the substrate 11 to prevent the intrusion of moisture. Since the moisture-proof layer 21 is formed on the inside of the bottom wall portion 111 and the inside of the side wall portion 112, the moisture-proof layer 21 has a first portion that covers the first electrode 12 and a second portion that covers the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, the side surface of the photoelectric conversion layer 14, the side surface of the second carrier transport layer 15, the side surface of the buffer layer 16 and the side surface of the second electrode 17.

[0036] Furthermore, on the opening side of the recess 110, the leading edge of the moisture-proof layer 21 (more specifically, the leading edge of the second portion of the moisture-proof layer 21) is connected to the aforementioned moisture-proof layer 20 provided on the second electrode 17 side. In this way, it is possible to prevent moisture from entering due to discontinuity between the moisture-proof layer 20 and the moisture-proof layer 21.

[0037] The moisture-proof layer 21, like the moisture-proof layer 20 provided on the second electrode 17 side, is a dense inorganic material layer and is formed of a metal oxide or inorganic oxide (for example, Al2O3, TiO2, ZnO, SnO2).

[0038] The manufacturing method for the solar cell module 1A configured as described above includes a recess preparation step and a lamination step, similar to the first embodiment, but the recess preparation step differs from the first embodiment because it is necessary to further form a moisture-proof layer 21.

[0039] Specifically, in the recess preparation step, as shown in Figure 4, first a flat substrate 200 is prepared (see Figure 4(a)). Next, the flat substrate 200 is processed to form a recess 110 having a bottom wall portion 111 and side wall portions 112 (see Figure 4(b)). After that, a moisture-proof layer 21 made of oxide (e.g., Al2O3) is deposited on the inner wall surface of the bottom wall portion 111 and the inner wall surface of the side wall portion 112 using atomic layer deposition (see Figure 4(c)).

[0040] In the lamination process, the first electrode 12, first carrier transport layer 13, photoelectric conversion layer 14, second carrier transport layer 15, buffer layer 16, and second electrode 17 are sequentially deposited and laminated on the moisture-proof layer 21 formed on the bottom wall portion 111. Subsequently, a moisture-proof layer 20 made of oxide (e.g., Al2O3) is deposited on the second electrode 17, the tip surface of the side wall portion 112, and the tip surface of the moisture-proof layer 21 by atomic layer deposition.

[0041] According to the solar cell module 1A of this embodiment, the same effects as those of the first embodiment described above can be obtained, and in addition, a moisture-proof layer 21 is further formed on the inside of the bottom wall portion 111 and the inside of the side wall portion 112, so the moisture-proof layer 21 also plays a role in preventing moisture intrusion. That is, in this embodiment, in addition to preventing moisture intrusion by the side wall portion 112 of the substrate 11, moisture intrusion can also be prevented by the moisture-proof layer 21 formed on the inside of the side wall portion 112 and the inside of the bottom wall portion 111. In this way, the cooperation of the side wall portion 112 and the moisture-proof layer 21 can further enhance the effect of preventing moisture intrusion from the side of the photoelectric conversion layer 14.

[0042] In this embodiment, an example of a moisture-proof layer 21 has been described having a first portion that covers the first electrode 12 and a second portion that covers the sides of the first electrode 12, the first carrier transport layer 13, the photoelectric conversion layer 14, the second carrier transport layer 15, the buffer layer 16, and the second electrode 17, but it is not limited to this. The moisture-proof layer 21 may have only portions that cover the sides of the first electrode 12, the first carrier transport layer 13, the photoelectric conversion layer 14, the second carrier transport layer 15, the buffer layer 16, and the second electrode 17.

[0043] [Third Embodiment] A third embodiment of the solar cell module will be described below with reference to Figure 5. The solar cell module 1B of this embodiment differs from the second embodiment described above in the shape of the side wall portion 112B of the substrate 11B. The other structures are the same as those of the second embodiment, so a redundant explanation will be omitted.

[0044] Figure 5 is a schematic cross-sectional view showing a solar cell module according to the third embodiment. As shown in Figure 5, in the solar cell module 1B of this embodiment, the side wall portion 112B of the substrate 11B is inclined such that the space of the recess 110B widens as it moves from the bottom wall portion 111 towards the opening side of the recess 110B. More specifically, the side wall portion 112B has a triangular cross-sectional shape that narrows from the bottom wall portion 111 side towards the opening side of the recess 110B, and is formed to cover the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, and the side surface of the photoelectric conversion layer 14. On the other hand, the side surface of the second carrier transport layer 15, the side surface of the buffer layer 16, and the side surface of the second electrode 17 are not covered by the side wall portion 112B.

[0045] Furthermore, the moisture-proof layer 21B formed on the inside of the side wall portion 112B is formed inclined to conform to the shape of the inner wall surface of the side wall portion 112B, so as to widen the space of the recess 110B. As shown in Figure 5, the moisture-proof layer 21B is formed to cover the side surface of the first electrode 12, the side surface of the first carrier transport layer 13, and the side surface of the photoelectric conversion layer 14.

[0046] Furthermore, in this embodiment, the moisture-proof layer 20B positioned on the second electrode 17 side is formed to have a second portion that covers the side surface of the second electrode 17, the side surface of the buffer layer 16, and the side surface of the second carrier transport layer 15, in addition to the first portion that covers the second electrode 17. On the side surface of the solar cell module 1B, the second portion of the moisture-proof layer 20B is connected to the second portion of the moisture-proof layer 21B. This prevents moisture from entering due to discontinuities between the moisture-proof layer 20B and the moisture-proof layer 21B.

[0047] The manufacturing method for the solar cell module 1B configured as described above includes a recess preparation step and a stacking step, similar to the second embodiment, but the stacking step differs from that of the second embodiment due to the difference in the shape of the side wall portion 112B.

[0048] Specifically, in the recess preparation step, as shown in Figure 6, first a flat substrate 200 is prepared (see Figure 6(a)). Next, the flat substrate 200 is processed to form a recess 110B having a bottom wall portion 111 and side wall portions 112B (see Figure 6(b)). At this time, the recess 110B is formed such that the side wall portion 112B narrows from the bottom wall portion 111 side toward the opening side of the recess 110B, that is, it has a triangular cross-section.

[0049] Subsequently, a moisture-proof layer 21B made of oxide (e.g., Al2O3) is deposited on the inner wall surface of the bottom wall portion 111 and the inner wall surface of the side wall portion 112B by atomic layer deposition (see Figure 6(c)).

[0050] In the lamination process, the first electrode 12, first carrier transport layer 13, photoelectric conversion layer 14, second carrier transport layer 15, buffer layer 16, and second electrode 17 are sequentially formed and laminated on the moisture-proof layer 21B formed on the bottom wall portion 111 and the side wall portion 112B. Subsequently, a moisture-proof layer 20B made of oxide (e.g., Al2O3) is deposited on the second electrode 17, the leading surface of the moisture-proof layer 21B, the side surface of the second electrode 17, the side surface of the buffer layer 16, and the side surface of the second carrier transport layer 15 by atomic layer deposition.

[0051] The solar cell module 1B according to this embodiment provides the same effects as the second embodiment described above. Furthermore, the side wall portion 112B of the substrate 11B is inclined such that the space of the recess 110B widens as it moves from the bottom wall portion 111 towards the opening side of the recess 110B. This allows for easy formation of a moisture-proof layer 21B inside the side wall portion 112B, improving the film-forming properties of the moisture-proof layer 21B. Moreover, the inclination of the side wall portion 112B such that the space of the recess 110B widens as it moves from the bottom wall portion 111 towards the opening side of the recess 110B makes it easier for unwanted photoelectric conversion layers 14 to escape when forming a photoelectric conversion layer 14 using, for example, a coating method.

[0052] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of Symbols]

[0053] 1,1A,1B: Solar cell module, 10: Cell, 11,11B: Substrate, 12: First electrode, 13: First carrier transport layer, 14: Photoelectric conversion layer, 15: Second carrier transport layer, 16: Buffer layer, 17: Second electrode, 18: Hole extraction electrode, 19: Electron extraction electrode, 20,20B,21,21B: Moisture-proof layer, 22: Divided groove, 23: Inter-cell conductive section, 110,110B: Recess, 111: Bottom wall section, 112,112B: Side wall section

Claims

1. A solar cell module comprising, in this order, a light-transmitting substrate, a first electrode, a photoelectric conversion layer containing a perovskite compound, and a second electrode, The substrate has a recess having a bottom wall portion that extends along the plane of the photoelectric conversion layer and covers the first electrode, and a side wall portion that extends along the thickness direction of the photoelectric conversion layer. The solar cell module is characterized in that the side wall portion is formed to cover at least the side surface of the first electrode and the side surface of the photoelectric conversion layer.

2. The solar cell module according to claim 1, wherein a moisture-proof layer formed of oxide is provided on the inside of the bottom wall and the inside of the side wall, at least on the inside of the side wall.

3. The solar cell module according to claim 2, wherein the side wall portion is inclined such that the space of the recess widens as it moves from the bottom wall portion toward the opening side of the recess.

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