Perovskite solar battery

Abstract

To provide a perovskite solar battery in which performance degradation is suppressed.SOLUTION: A perovskite solar battery 100 has a conductive layer 2 arranged on a substrate 1, a solar battery element 3 arranged on the conductive layer 2, an electrode 4 arranged on the solar battery element 3, a sealing layer 7 encapsulating the solar battery element 3, an adhesive layer 6 bonding the sealing layer 7 to the conductive layer 2, and an insulating non-adhesive layer 5 arranged between electrode 4 and adhesive layer 6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to perovskite solar cells.

Background Art

[0002] A perovskite solar cell, which is a type of solar cell that converts solar light energy into electrical energy, has attracted attention because it has a high energy conversion efficiency and is lightweight compared to other solar cells. However, perovskite solar cells have a problem in that they are easily deteriorated by oxygen, water, etc., and various technologies have been proposed for these problems (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a perovskite solar cell including a support, a solar cell element provided on the support, an adhesive layer covering the entire solar cell element, and a sealing agent layer covering the entire adhesive layer to prevent water or the like from entering the solar cell element.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the perovskite solar cell disclosed in Patent Document 1, the entire solar cell element is covered with an adhesive layer. Therefore, for example, in a configuration where electrodes are arranged on the solar cell element, the electrodes adhere to the adhesive layer, and when the perovskite solar cell vibrates due to, for example, an impact being applied, and the relative positions of the adhesive layer and the electrodes change, the electrodes may peel off from the solar cell element, and the performance of the perovskite solar cell may deteriorate.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a perovskite solar cell in which a decrease in performance is suppressed.

Means for Solving the Problems

[0007] The characteristic configuration of the perovskite solar cell in view of the above is a conductive conductive layer disposed on a substrate, a solar cell element disposed on the conductive layer, an electrode disposed on the solar cell element, a sealing layer for sealing the solar cell element, an adhesive layer for adhering the sealing layer and the conductive layer, and an insulating non-adhesive layer disposed between the electrode and the adhesive layer.

[0008] According to such a characteristic configuration, since a non-adhesive layer is disposed between the electrode and the adhesive layer, contact between the electrode and the adhesive layer can be avoided. Thereby, for example, even when the relative position of the adhesive layer and the electrode changes due to an impact or the like, peeling of the electrode from the solar cell element is prevented. As a result, a decrease in the performance of the perovskite solar cell can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the perovskite solar cell according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.

[0011] 〔Schematic Configuration of Perovskite Solar Cell〕 As shown in FIG. 1, the perovskite solar cell 100 includes a substrate 1, a conductive layer 2, a solar cell element 3, an electrode 4, a non-adhesive layer 5, an adhesive layer 6, a barrier layer 7 (an example of a sealing layer), and a base material layer 8. In the present embodiment, the adhesive layer 6, the barrier layer 7, and the base material layer 8 are integrally formed in a sheet shape. Hereinafter, the adhesive layer 6, the barrier layer 7, and the base material layer 8 may be referred to as a "sealing sheet 9".

[0012] 〔Substrate〕 The substrate 1 functions as a support for the perovskite solar cell 100. The substrate 1 is a transparent glass substrate, a translucent glass substrate, a transparent resin substrate, etc., and has insulating properties. As shown in FIG. 2, the substrate 1 is rectangular when viewed along the Z direction.

[0013] As shown in FIG. 1, a conductive conductive layer 2 is laminated on the substrate 1. The orientation of the perovskite solar cell 100 during use is not particularly limited. Hereinafter, the direction from the substrate 1 to the conductive layer 2 is referred to as the "Z1 direction" (an example of the lamination direction), the opposite direction is referred to as the "Z2 direction", and the Z1 direction and the Z2 direction are collectively referred to as the "Z direction". Also, one of the directions orthogonal to the Z direction is referred to as the "X direction", and the direction orthogonal to the Z direction and the X direction is referred to as the "Y direction" (see FIG. 2). Note that FIG. 2 is a view of the perovskite solar cell 100 shown in FIG. 1 viewed along the Z direction.

[0014] 〔Conductive Layer〕 The conductive layer 2 is formed on one surface (the surface in the Z1 direction) of the substrate 1 by CVD (Chemical Vapor Deposition), sputtering, or the like. In the present embodiment, the conductive layer 2 is formed on the entire surface of one surface of the substrate 1. The conductive layer 2 contains, for example, fluorine-doped tin oxide (FTO), tin oxide (TO), etc. as materials. The solar cell element 3 is disposed (laminated) on the conductive layer 2 (the surface in the Z1 direction).

[0015] 〔Solar cell element〕 The solar cell element 3 converts light energy into electrical energy. The solar cell element 3 has an electron transport layer 31, a photoelectric conversion layer 32, and a hole transport layer 33, and the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 are arranged in this order along the Z1 direction. When viewed along the Z direction, each of the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 is rectangular, and in the present embodiment, when viewed along the Z direction, the sizes (areas) of each of the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 are equal.

[0016] The electron transport layer 31 is disposed on the Z1-direction surface of the conductive layer 2. The electron transport layer 31 allows electrons received from the photoelectric conversion layer 32 described later to pass through (transport electrons). The electron transport layer 31 contains, for example, a metal oxide such as titanium oxide, tin oxide, or zinc oxide as a material. In the present embodiment, the electron transport layer 31 includes an insulating layer 311 that extends into a recess 21 formed by removing a part of the conductive layer 2. The insulating layer 311 partitions the conductive layer 2 into two (partitioned into two in the X direction in the example shown in FIG. 1). Electrons can move in the direction along the Z direction in the electron transport layer 31, but it is difficult for them to move in the directions orthogonal to the Z direction (the X direction and the Y direction), and the movement between the two partitions of the conductive layer 2 is restricted. Note that the electron transport layer 31 may sometimes be referred to as a "blocking layer".

[0017] Since the substrate 1, the conductive layer 2, and the electron transport layer 31 have light transmissivity, light such as sunlight and indoor light is guided to the photoelectric conversion layer 32 without being substantially absorbed (or without being absorbed) by the substrate 1, the conductive layer 2, and the electron transport layer 31.

[0018] The photoelectric conversion layer 32 absorbs light energy and converts it into electrical energy. Specifically, the photoelectric conversion layer 32 absorbs light and moves excited electrons and holes to perform photoelectric conversion. The photoelectric conversion layer 32 includes a perovskite layer composed of a perovskite compound. Further, the photoelectric conversion layer 32 further includes a porous semiconductor oxide layer (for example, a porous titanium layer).

[0019] The hole transport layer 33 allows holes received from the photoelectric conversion layer 32 to pass through (transport holes). The hole transport layer 33 contains, for example, an organic compound such as chlorobenzene as a material. An electrode 4 is disposed on the hole transport layer 33 (the surface in the Z1 direction).

[0020] 〔Electrode〕 The electrode 4 has conductivity and forms an electrical path with the conductive layer 2 (negative electricity) via the bus bar B as a positive electrode.

[0021] As shown in FIG. 2, when viewed along the Z direction, the bus bar B is disposed (laminated) on the surface in the Z1 direction of the conductive layer 2 outside (outside in the X direction) the solar cell element 3. Specifically, the bus bar B is disposed spaced apart from the solar cell element 3 on the surface in the Z1 direction (a partial region) of the conductive layer 2. The bus bar B contains, as a material, a single metal such as gold, platinum, silver, copper, an alloy thereof, an oxide conductor such as FTO, ITO, or the like.

[0022] As shown in FIG. 1, the electrode 4 is disposed on the surface in the Z1 direction (a partial region) of the conductive layer 2 along the Z direction from the surface in the Z1 direction of the hole transport layer 33 via the respective side surfaces of the solar cell element 3 (see also FIG. 3). The electrode 4 contains, for example, a carbon nanotube (an example of an active material) as a material.

[0023] 〔Non - adhesive layer〕 The non - adhesive layer 5 has insulation and is disposed between the electrode 4 and the adhesive layer 6 in the Z direction. The non - adhesive layer 5 is a film - shaped (sheet - shaped) member. In this embodiment, the size (length) in the Z direction is 69 ± 0.5 μm. Hereinafter, the length in the Z direction may be referred to as "thickness".

[0024] As shown in FIG. 2, in the present embodiment, the non-adhesive layer 5 is rectangular when viewed along the Z direction. The size (length) of the non-adhesive layer 5 in the X direction is 280.48 ± 0.05 mm, and the size (length) in the Y direction is 285 ± 0.05 mm. Note that the size (length) of the substrate 1 in each of the X direction and the Y direction is 300 ± 0.2 mm. Also, the size (length) of the region on the substrate 1 where the electrode 4 can be disposed in the X direction is 279.48 ± 0.02 mm, and the size (length) in the Y direction is 283.8 ± 0.15 mm. That is, when viewed along the Z direction, the size (area) of the non-adhesive layer 5 is larger than the area of the region where the electrode 4 can be disposed (that is, the size (area) of the electrode 4). In other words, when viewed along the Z direction, the non-adhesive layer 5 is disposed so as to include the entire region of the electrode 4 and overlaps with the entire region of the electrode 4. Note that since the non-adhesive layer 5 also has a function of protecting the electrode 4, it may be referred to as a "protective layer".

[0025] A plurality of communication holes (air holes) that communicate the inside and the outside of the non-adhesive layer 5 are formed in the non-adhesive layer 5. The non-adhesive layer 5 is, for example, a porous film, a mesh sheet, an embossed sheet, etc., and contains resin (PPS: polyphenylene sulfide resin), glass, etc. as materials. The non-adhesive layer 5 has a melting point (for example, 120 degrees or higher) higher than the temperature (for example, 80 degrees) at the time of bonding the barrier layer 7 and the conductive layer 2 via the adhesive layer 6.

[0026] 〔Adhesive layer〕 The adhesive layer 6 is, for example, an acrylic-based adhesive, and in the present embodiment, the thickness is 50 ± 0.5 μm. As shown in FIG. 1, the adhesive layer 6 is disposed between the conductive layer 2 and the barrier layer 7 in the Z direction. Specifically, the adhesive layer 6 is disposed so as to sandwich the solar cell element 3, the electrode 4, and the non-adhesive layer 5 between the conductive layer 2.

[0027] As shown in FIG. 2, when viewed along the Z direction, the size (area) of the adhesive layer 6 is larger than the size (area) of the non-adhesive layer 5, and the adhesive layer 6 has an extending portion 61 that extends outward from the non-adhesive layer 5.

[0028] The extending portion 61 of the subsequent layer 6 is arranged to surround the solar cell element 3, the electrode 4, and the non-adhesive layer 5 when viewed along the Z direction, and is adhered (bonded) to the conductive layer 2 and the barrier layer 7 (sealing sheet 9). Thereby, an internal space S for accommodating the solar cell element 3, the electrode 4, and the non-adhesive layer 5 is formed between the adhesive layer 6 (sealing sheet 9) and the conductive layer 2. The barrier layer 7 is disposed on the surface of the adhesive layer 6 in the Z1 direction (see FIG. 1).

[0029] 〔Barrier layer〕 The barrier layer 7 is a sheet-like sealant having conductivity. In this embodiment, the thickness is 15 ± 0.5 μm. The barrier layer 7 contains metal oxides such as aluminum oxide and silicon oxide, and metals such as aluminum as materials. The barrier layer 7 seals the internal space S (solar cell element 3) by preventing the entry of water, oxygen, etc. into the internal space S. In this embodiment, the internal space S is set to a vacuum. Further, the internal space S may be filled with an inert gas such as nitrogen gas or noble gas. The base material layer 8 is disposed on the surface of the barrier layer 7 in the Z1 direction.

[0030] 〔Base material layer〕 The base material layer 8 is a sheet-like base material. In this embodiment, the thickness is 12 ± 0.5 μm. The base material layer 8 contains resins such as PET (polyethylene terephthalate) as materials. In this embodiment, the size (length) of the sealing sheet 9 in the X direction is 290 ± 0.2 mm, and the size (length) in the Y direction is 299.8 ± 0.2 mm. That is, the size (area) of the sealing sheet 9 is larger than the size (area) of the non-adhesive layer 5. When viewed along the Z direction, the sizes (areas) of the adhesive layer 6, the barrier layer 7, and the base material layer 8 constituting the sealing sheet 9 are equal.

[0031] When light reaches the photoelectric conversion layer 32 through the substrate 1, the conductive layer 2, and the electron transport layer 31, it is absorbed in the photoelectric conversion layer 32, and as a result, electrons and holes are generated. The electrons generated in the photoelectric conversion layer 32 move to the conductive layer 2 (negative electrode) through the electron transport layer 31. At the same time, the holes generated in the photoelectric conversion layer 32 move to the electrode 4 (positive electrode) that is electrically connected to the hole transport layer 33. When a load (not shown) is connected between the conductive layer 2 and the electrode 4, the holes combine with the electrons that have passed through the load. As a result, electricity is generated. Although the electrons moving through the electron transport layer 31 smoothly move along the Z2 direction and reach the conductive layer 2, as described above, the movement in the direction orthogonal to the Z direction is restricted by the insulating layer 311. That is, the perovskite solar cell 100 is configured so as not to short-circuit.

[0032] 〔Adhesion method of the encapsulation sheet〕 Next, with reference to FIGS. 3 to 5, the method of adhering the encapsulation sheet 9 to the conductive layer 2 (the conductive layer 2 disposed on the substrate 1) will be described.

[0033] In the present embodiment, as shown in FIG. 3, the first laminate S1 in which the substrate 1, the conductive layer 2, the solar cell element 3, and the electrode 4 are laminated is disposed in a vacuum chamber (first disposition step). Then, as shown in FIG. 4, the non-adhesive layer 5 is disposed on the surface of the first laminate S1 in the Z1 direction, and the encapsulation sheet 9 is disposed on the surface of the non-adhesive layer 5 in the Z1 direction (second disposition step). Hereinafter, the laminate in which the non-adhesive layer 5 and the encapsulation sheet 9 are disposed on the first laminate S1 is referred to as "second laminate S2". In the second laminate S2 before evacuating the inside of the vacuum chamber, a gap is formed between the conductive layer 2 and the adhesive layer 6 due to the interposition of the non-adhesive layer 5. As described above, in the second laminate S2, when viewed along the Z direction, the size of the non-adhesive layer 5 is larger (slightly larger) than the size of the electrode 4 and smaller than the size of the encapsulation sheet 9 (adhesive layer 6).

[0034] Thereafter, the internal space S is evacuated by setting the inside of the vacuum chamber to a vacuum (e.g., 10 Pa) (vacuum step). Next, as shown in FIG. 5, the diaphragm D is used to apply air pressure (e.g., pressurize to 0.1 to 0.3 MPa) (pressurization step). As a result, the non-adhesive layer 5 and the sealing sheet 9 are compressed (the non-adhesive layer 5 is compressed so as to be adsorbed to the conductive layer 2, the solar cell element 3, the electrode 4, and the non-adhesive layer 5). As described above, the non-adhesive layer 5 has a plurality of communication holes. For this reason, when the internal space S becomes a vacuum, the non-adhesive layer 5 is compressed by the solar cell element 3, the electrode 4, and the sealing sheet 9, and at least a part of the solar cell element 3 and at least a part of the electrode 4 are buried in the non-adhesive layer 5. In FIGS. 1 and 5, the non-adhesive layer 5 and the sealing sheet 9 are shown as not being compressed, but actually, the non-adhesive layer 5 and the sealing sheet 9 are compressed.

[0035] Thereafter, the pressurized second laminate S2 is heated (the inside of the vacuum chamber is heated at, for example, 80 degrees) (heating step). As a result, the adhesive layer 6 melts, and the barrier layer 7 (sealing sheet 9) and the conductive layer 2 are adhered (bonded) via the adhesive layer 6. Specifically, the barrier layer 7 and the conductive layer 2 are adhered via the extending portion 61 of the adhesive layer 6. The heating time is, for example, 3 minutes.

[0036] For example, in the case of an adhesive that uses light energy or thermal energy to bond a sealing sheet to a substrate (conductive layer), after bonding the substrate and the sealing sheet, it is not possible to evacuate the space where the solar cell element is disposed between the substrate and the sealing sheet to a vacuum. If the space between the substrate and the sealing sheet cannot be evacuated to a vacuum, there is a possibility that oxygen and / or water may remain in the above space, and the remaining oxygen and / or water may come into contact with the solar cell element, potentially causing degradation of the perovskite solar cell. In contrast, according to the present embodiment, since the non-adhesive layer 5 is interposed between the conductive layer 2 (substrate 1) and the adhesive layer 6, in the second laminate S2 before the internal space S is evacuated to a vacuum, a gap can be formed between the conductive layer 2 (substrate 1) and the adhesive layer 6. That is, since the gas in the internal space S can be sucked (discharged to the outside) through the gap, the internal space S can be easily evacuated to a vacuum. Also, since the gas in the internal space S can be sucked (discharged to the outside) through the plurality of communication holes provided in the non-adhesive layer 5, the internal space S can be more reliably evacuated to a vacuum. In this way, since the internal space S is set to a vacuum and the sealing sheet 9 (barrier layer 7) is configured to prevent the entry of water, oxygen, etc. into the internal space S as described above, degradation (oxidation) of the solar cell element 3 is prevented, and degradation of the perovskite solar cell 100 is suppressed.

[0037] In addition, since the internal space S can be more reliably evacuated to a vacuum, it is possible to prevent gas (air) from remaining in the internal space S, and in the perovskite solar cell 100, the generation of bubbles can be reduced. If bubbles are present in the adhesive portion (extended portion 61) between the sealing sheet 9 (barrier layer 7) and the conductive layer 2, the adhesive strength between the sealing sheet 9 (barrier layer 7) and the conductive layer 2 may decrease, making it easier for oxygen, water, etc. to enter the internal space S, potentially reducing the performance of the perovskite solar cell 100. However, according to the present embodiment, a gap is formed by the non-adhesive layer 5 between the conductive layer 2 and the adhesive layer 6, making the adhesive layer 6 easier to handle, and the generation of bubbles in the perovskite solar cell 100 (including the extended portion 61) can be reduced. As a result, a decrease in the performance of the perovskite solar cell 100 is suppressed.

[0038] Also, for example, in a configuration where a sealing sheet (adhesive layer) is adhered to a substrate using a heat - pressure bonding roller or the like, the electrode disposed on the substrate (or on the solar cell element) and the adhesive layer adhere to each other. In this case, there is a risk that the electrode may peel off due to an impact (vibration), leading to a deterioration in the performance of the battery. On the other hand, according to the present embodiment, as described above, since the non - adhesive layer 5 is disposed between the adhesive layer 6 and the electrode 4, the adhesive layer 6 and the electrode 4 do not adhere to each other, and peeling of the electrode 4 due to an impact (vibration) can be prevented.

[0039] 〔Outline of the above - described embodiment〕 In the above - described embodiment, the following configuration is recalled.

[0040] (1) A perovskite solar cell 100 having a conductive conductive layer 2 disposed on a substrate 1, a solar cell element 3 disposed on the conductive layer 2, an electrode 4 disposed on the solar cell element 3, a barrier layer 7 (sealing layer) for sealing the solar cell element 3, an adhesive layer 6 for adhering the barrier layer 7 (sealing layer) and the conductive layer 2, and an insulating non - adhesive layer 5 disposed between the electrode 4 and the adhesive layer 6.

[0041] According to this configuration, since the insulating non - adhesive layer 5 is disposed between the electrode 4 and the adhesive layer 6, contact between the electrode 4 and the adhesive layer 6 can be avoided. Therefore, for example, even when the perovskite solar cell 100 vibrates due to an impact being applied or the like, and the relative positions of the adhesive layer 6 and the electrode 4 change, the electrode 4 is protected by the non - adhesive layer 5, so that peeling of the electrode 4 from the solar cell element 3 is prevented. As a result, a deterioration in the performance of the perovskite solar cell 100 can be suppressed.

[0042] (2) In the perovskite solar cell 100 of (1), it is preferable that the non - adhesive layer 5 has a melting point higher than the temperature at which the barrier layer 7 (sealing layer) and the conductive layer 2 are adhered via the adhesive layer 6.

[0043] According to this configuration, since the non-adhesive layer 5 has a melting point higher than the temperature at which the adhesive layer 6 adheres the barrier layer 7 and the conductive layer 2, even when the perovskite solar cell 100 is heated for adhesion by the adhesive layer 6, the non-adhesive layer 5 does not melt and can prevent adhesion to the electrode 4. For this reason, for example, even when the perovskite solar cell 100 vibrates due to being impacted or the like and the relative position of the non-adhesive layer 5 and the electrode 4 changes, peeling of the electrode 4 from above the solar cell element 3 is prevented. As a result, a decrease in the performance of the perovskite solar cell 100 can be suppressed.

[0044] (3) In the perovskite solar cell 100 of (1) or (2), it is preferable that the non-adhesive layer 5 overlaps the entire region of the electrode 4 in the Z direction (first direction) from the substrate 1 toward the conductive layer 2.

[0045] According to this configuration, since the non-adhesive layer 5 covers the entire region of the electrode 4 in the Z direction, the electrode 4 can be more reliably protected (peeling of the electrode 4 is prevented).

[0046] (4) In the perovskite solar cell 100 of (3), when viewed along the Z direction (first direction), the adhesive layer 6 preferably has an extending portion 61 that extends outward from the non-adhesive layer 5, and the extending portion 61 is adhered to the conductive layer 2.

[0047] According to this configuration, since the extending portion 61 of the adhesive layer 6 that extends outward from the non-adhesive layer 5 is adhered to the conductive layer 2, the solar cell element 3 can be more reliably protected while being sealed.

[0048] 〔Other Embodiments〕 Next, other embodiments will be described.

[0049] (a) The configurations disclosed in each of the above embodiments can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Regarding other configurations as well, all the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of the present disclosure.

[0050] (b) The sizes (area or length) described in the above embodiments are examples, and can be appropriately changed as long as the size when viewed along the Z direction is such that the sealing sheet 9 > non - adhesive layer 5 > electrode 4 (when viewed along the Z direction, the size of the sealing sheet 9 is larger than the size of the non - adhesive layer 5, and the size of the non - adhesive layer 5 is larger than the size of the electrode 4).

[0051] (c) In the above - described embodiment, the adhesive layer 6 is provided in the entire region of the sealing sheet 9, but it may be provided only at the bonding site with the conductive layer 2 on the lower surface of the sealing sheet 9. Also, the sealing sheet 9 may omit the base material layer 8.

Industrial Applicability

[0052] The technology according to the present disclosure can be used in perovskite solar cells.

Explanation of Reference Numerals

[0053] 1: Substrate, 2: Conductive layer, 3: Solar cell element, 4: Electrode, 5: Non - adhesive layer, 6: Adhesive layer, 61: Extending portion, 7: Barrier layer, 100: Perovskite solar cell

Claims

1. A conductive conductive layer disposed on a substrate, a solar cell element disposed on the conductive layer, an electrode disposed on the solar cell element, a sealing layer for sealing the solar cell element, an adhesive layer for adhering the sealing layer and the conductive layer, and a perovskite solar cell having an insulating non - adhesive layer disposed between the electrode and the adhesive layer.

2. The perovskite solar cell according to claim 1, wherein the non - adhesive layer has a melting point higher than the temperature at which the sealing layer and the conductive layer are adhered via the adhesive layer.

3. The perovskite solar cell according to claim 1 or 2, wherein the non - adhesive layer overlaps the entire area of the electrode in a first direction from the substrate toward the conductive layer.

4. When viewed along the first direction, the adhesive layer has an extending portion that extends outward beyond the non - adhesive layer, and the perovskite solar cell according to claim 3, wherein the extending portion is adhered to the conductive layer.

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