WO2016208034A1 - Solar cell module - Google Patents

Solar cell module Download PDF

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Publication number
WO2016208034A1
WO2016208034A1 PCT/JP2015/068351 JP2015068351W WO2016208034A1 WO 2016208034 A1 WO2016208034 A1 WO 2016208034A1 JP 2015068351 W JP2015068351 W JP 2015068351W WO 2016208034 A1 WO2016208034 A1 WO 2016208034A1
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WO
WIPO (PCT)
Prior art keywords
solar cell
power generation
light absorption
generation unit
solar
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2015/068351
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French (fr)
Japanese (ja)
Inventor
祐弥 保西
武士 新井本
山本　和重
中川　直之
総一郎 芝崎
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Toshiba Corp
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Toshiba Corp
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Publication date
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Priority to PCT/JP2015/068351 priority Critical patent/WO2016208034A1/en
Publication of WO2016208034A1 publication Critical patent/WO2016208034A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F19/00—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules
    • H10F19/30—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules comprising thin-film photovoltaic cells
    • H10F19/31—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules comprising thin-film photovoltaic cells having multiple laterally adjacent thin-film photovoltaic cells deposited on the same substrate
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/60—Arrangements for cooling, heating, ventilating or compensating for temperature fluctuations
    • H10F77/63—Arrangements for cooling directly associated or integrated with photovoltaic cells, e.g. heat sinks directly associated with the photovoltaic cells or integrated Peltier elements for active cooling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • Embodiment of this invention is related with a solar cell module.
  • a solar cell module having a general tandem structure has a structure in which a film to be a bottom cell and a film to be a top cell are stacked on the same substrate.
  • a silicon-based solar cell module has a structure in which a film made of crystalline silicon and a film made of amorphous silicon are stacked on the same substrate.
  • the conversion efficiency of the solar cell module having such a tandem structure is, for example, about 13.5%. That is, the conversion efficiency of a solar cell module having a general tandem structure is actually lower than the conversion efficiency of a single-layer crystalline silicon solar cell. The reason why the conversion efficiency of a solar cell module having a general tandem structure is low is that amorphous silicon having many crystal defects is used.
  • JP 2000-252496 A Japanese Patent Laying-Open No. 2015-65249
  • the problem to be solved by the present invention is to provide a solar cell module capable of improving the reliability.
  • the solar cell module includes a first power generation unit having a plurality of first solar cells electrically connected in parallel, and a plurality of second solar cells electrically connected in series, A second power generation unit provided on a side opposite to the light incident side of the first power generation unit and electrically connected in parallel with the first power generation unit.
  • the first solar cell has a plurality of first light absorption layers electrically connected in series.
  • FIG. 1 is a schematic exploded view for illustrating a solar cell module 1 according to the present embodiment.
  • 4 is a schematic plan view for illustrating a solar battery cell 40.
  • FIG. 3 is a schematic cross-sectional view for illustrating a solar battery cell 40.
  • FIG. 4 is a schematic plan view for illustrating connection of a plurality of solar cells 40.
  • FIG. 3 is a schematic plan view for illustrating a solar battery cell 60.
  • FIG. (A), (b) is a schematic cross section for illustrating the photovoltaic cell 60.
  • FIG. 4 is a schematic plan view for illustrating connection of a plurality of solar cells 60.
  • FIG. FIG. 8 is a cross-sectional view taken along line AA in FIG. FIG.
  • FIG. 6 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
  • FIG. 6 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
  • 4 is a graph for illustrating the relationship between a region where the conversion efficiency of the solar battery cell 40 is less than or equal to a theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
  • FIG. 4 is a graph for illustrating the relationship between a region where the conversion efficiency of the solar battery cell 40 is less than or equal to a theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
  • FIG. 6 is a graph for illustrating the relationship between a region where the conversion efficiency of the solar battery cell 40 is less than or equal to a theoretical value, the band gap of the light ab
  • FIG. 1 is a schematic exploded view for illustrating a solar cell module 1 according to the present embodiment.
  • the solar cell module 1 includes a protection unit 2, a sealing unit 3, a power generation unit 4 (corresponding to an example of a first power generation unit), an insulating unit 5, and a power generation unit 6 (second power generation unit).
  • the sealing part 7 and the protection part 8 are provided.
  • the protection unit 2 has a plate shape, and is provided on the light receiving surface side (incident surface side of the light L) of the power generation unit 4 and the power generation unit 6.
  • the protection unit 2 transmits light L such as sunlight and protects the light receiving surface sides of the power generation unit 4 and the power generation unit 6.
  • the protection unit 2 can be formed using, for example, an inorganic material such as glass or an organic material such as a translucent resin.
  • the inorganic material such as glass can be, for example, non-alkali glass, quartz glass, glass containing an alkali metal, or the like.
  • the glass containing an alkali metal can be, for example, soda-lime glass.
  • a solar battery cell 40 (corresponding to an example of a first solar battery cell) or a solar battery cell 60 (corresponding to an example of a second solar battery cell) described later may be a CIGS solar battery cell.
  • the CIGS solar cell includes Cu (In, Ga) Se 2 . Therefore, in a CIGS solar cell, Cu diffuses and Cu defects may occur.
  • the protective part 2 is formed of glass containing an alkali metal, alkali metal ions (for example, Na ions, K ions, etc.) contained in the glass containing the alkali metal enter the Cu deficient portion by substitution.
  • alkali metal ions enter the defect portion of Cu, the open circuit voltage increases, and as a result, the conversion efficiency can be increased.
  • the protection unit 2 may be formed of glass containing an alkali metal such as soda lime glass.
  • the organic material such as a translucent resin can be, for example, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamideimide, liquid crystal polymer, cycloolefin polymer, or the like.
  • the protection part 2 is preferably formed from an inorganic material having low moisture permeability.
  • the sealing unit 3 is provided between the protection unit 2 and the power generation unit 4.
  • the sealing part 3 may be filled also between several photovoltaic cells 40 mentioned later.
  • the sealing unit 3 seals the light receiving surface side of the power generation unit 4.
  • the sealing unit 3 suppresses, for example, water vapor or gas included in the environment where the solar cell module 1 is installed from reaching the power generation unit 4.
  • the sealing unit 3 transmits light incident on the sealing unit 3.
  • the sealing unit 3 joins the protection unit 2 and the power generation unit 4 together.
  • the sealing part 3 can also have the function to absorb the impact from the outside.
  • the sealing part 3 can be formed from, for example, ethylene-vinyl acetate copolymer (EVA), PVB (polyvinyl butyral), ionomer, or the like.
  • the power generation unit 4 is provided on the side opposite to the side on which the light L of the protection unit 2 is incident.
  • the power generation unit 4 includes a plurality of solar cells 40 and wirings 46 that electrically connect the plurality of solar cells 40 in parallel.
  • the solar battery cell 40 mainly absorbs light having a short wavelength in the incident light L and converts it into electric power. Of the incident light L, long wavelength light passes through the solar battery cell 40 and enters the solar battery cell 60 described later. Therefore, the solar battery cell 40 (light absorption layer 43 (corresponding to an example of the first light absorption layer)) is included in the solar battery cell 60 (light absorption layer 61 (corresponding to an example of the second light absorption layer)). It has a larger band gap than the band gap.
  • the solar battery cell 40 can be a CIGS solar battery cell having a high Ga content
  • the solar battery cell 60 can be a crystalline silicon solar battery cell.
  • the detail regarding the photovoltaic cell 40 and the photovoltaic cell 60 is mentioned later.
  • FIG. 2 is a schematic plan view for illustrating the solar battery cell 40.
  • FIG. 3 is a schematic cross-sectional view for illustrating the solar battery cell 40.
  • the solar battery cell 40 has a monolithic integrated structure in which a plurality of light absorption layers 43 are electrically connected in series.
  • the solar battery cell 40 includes a substrate 41, an electrode 42, a light absorption layer 43, a buffer layer 44, and an electrode 45.
  • the substrate 41 has a plate shape and transmits light that has not been absorbed by the light absorption layer 43.
  • the substrate 41 can be formed from the same material as that of the protection unit 2, for example.
  • the electrode 42 is provided on one surface of the substrate 41. A plurality of electrodes 42 are provided at a predetermined interval.
  • the light absorption layer 43 is electrically connected to one end side of the electrode 42, and the adjacent light absorption layer 43 is electrically connected to the other end side of the electrode 42.
  • the electrode 42 is formed from a material having translucency and conductivity.
  • the electrode 42 can be formed using, for example, a transparent electrode material such as ITO or ZnO.
  • the light absorption layer 43 is provided on the opposite side of the electrode 42 from the substrate 41 side. A plurality of light absorption layers 43 are provided with a predetermined interval. The light absorption layer 43 is provided so as to straddle between the electrodes 42 provided at a predetermined interval. The light absorption layer 43 mainly absorbs short wavelength light in the incident light L and converts it into electric power.
  • the light absorption layer 43 is preferably formed using a material having a band gap of 1.4 eV or more and 3.0 eV or less.
  • the light absorption layer 43 can be formed using a compound semiconductor containing Cu, In, Ga, and Se and having a high Ga content.
  • the solar battery cell 40 is a CIGS solar battery cell with a high Ga content.
  • the light absorption layer 43 can be formed using a compound semiconductor containing Cu, Zn, Sn, S, and Se.
  • the solar cell 40 is a CZTS solar cell.
  • the light absorption layer 43 may have a layer made of a p-type organic semiconductor material and a layer made of an n-type organic semiconductor material.
  • the solar cell 40 is an organic thin film solar cell.
  • the light absorption layer 43 can be formed using a material having a perovskite crystal structure. In this case, the solar cell 40 is a perovskite solar cell.
  • the buffer layer 44 is provided on the opposite side of the light absorption layer 43 from the electrode 42 side.
  • the buffer layer 44 is made of an n-type semiconductor. If low-resistance impurities are generated when the light absorption layer 43 is formed, a leakage current may be generated and conversion efficiency may be reduced. For this reason, a buffer layer 44 made of an n-type semiconductor is provided on the light absorption layer 43 made of a p-type semiconductor to suppress leakage current caused by impurities.
  • the buffer layer 44 can be formed from, for example, CdS, ZnS, or the like.
  • the electrode 45 is provided on the opposite side of the buffer layer 44 from the light absorption layer 43 side.
  • the electrode 45 is formed from a material having translucency and conductivity.
  • the electrode 45 can be formed from the same material as the electrode 42, for example.
  • the electrode 45 penetrates the light absorption layer 43 in the thickness direction and is electrically connected to the electrode 42. That is, as shown in FIG. 3, the plurality of light absorption layers 43 are electrically connected in series by the electrode 42 and the electrode 45.
  • the photovoltaic cell 40 Since the several light absorption layer 43 is connected in series, the photovoltaic cell 40 turns into a high voltage type photovoltaic cell. Further, the output voltage of the solar battery cell 40 can be changed by changing the material of the light absorption layer 43 and the number of light absorption layers 43 (number of grooves 47).
  • the solar battery cell 40 having the above configuration can be manufactured using, for example, a semiconductor manufacturing process. In this case, the light absorption layer 43 and the like can be divided by performing scribing (grooving) using a laser or the like.
  • FIG. 4 is a schematic plan view for illustrating the connection of a plurality of solar cells 40.
  • the plurality of solar cells 40 are electrically connected in parallel by wiring 46. Therefore, the output voltage of the power generation unit 4 is the same as the output voltage of the solar battery cell 40.
  • the output voltage of the solar battery cell 40 can be changed by changing the material of the light absorption layer 43 or the number of light absorption layers 43 (number of grooves 47). Therefore, the output voltage of the power generation unit 4 can be changed by changing the output voltage of the solar battery cell 40.
  • the insulating unit 5 is provided between the power generation unit 4 and the power generation unit 6.
  • the insulating unit 5 insulates between the power generation unit 4 and the power generation unit 6.
  • the insulating unit 5 transmits light incident on the insulating unit 5.
  • the insulating unit 5 joins the power generation unit 4 and the power generation unit 6. Therefore, the insulation part 5 has translucency and insulation, and also has a joining function.
  • the insulating part 5 can be provided with an adhesive layer made of an acrylic resin on the surface of a substrate made of alkali-free glass or quartz glass, for example.
  • the power generation unit 6 is provided on the side opposite to the light incident side of the power generation unit 4.
  • the power generation unit 6 is opposed to the power generation unit 4 via the insulating unit 5. That is, the solar cell module 1 has a tandem structure in which a power generation unit 4 (top cell) that absorbs light on the short wavelength side and a power generation unit 6 (bottom cell) that absorbs light on the long wavelength side are stacked.
  • the power generation unit 6 includes a plurality of solar cells 60 and a wiring 66 that electrically connects the plurality of solar cells 60 in series.
  • the solar battery cell 60 absorbs light (mainly long wavelength light) transmitted through the solar battery cell 40 and converts it into electric power.
  • FIG. 5 is a schematic plan view for illustrating the solar battery cell 60.
  • the antireflection film 65 is omitted in order to avoid complication.
  • FIGS. 6A and 6B are schematic cross-sectional views for illustrating the solar battery cell 60.
  • FIG. 6A is a cross-sectional view taken along line AA in FIG.
  • FIG. 6B is a cross-sectional view taken along line BB in FIG.
  • the solar battery cell 60 has a grid type structure.
  • the solar cell 60 is provided with a light absorption layer 61, an electrode 62, a grid electrode 63, a wiring connection electrode 64, and an antireflection film 65.
  • the light absorption layer 61 has a band gap smaller than that of the light absorption layer 43.
  • the light absorption layer 61 is preferably formed using a material having a band gap of 1.0 eV or more and 1.4 eV or less.
  • the light absorption layer 61 can be formed using crystalline silicon such as single crystal silicon, polycrystalline silicon, or microcrystalline silicon.
  • the solar battery cell 60 is a crystalline silicon solar battery cell.
  • the light absorption layer 61 can be formed using a compound semiconductor containing Cu, In, Ga, and Se and having a high In content.
  • the solar battery cell 60 is a CIGS solar battery cell having a large In content.
  • the light absorption layer 61 can be formed using CuInTe 2 (CIT).
  • the solar battery cell 60 is a CIT solar battery cell.
  • the light absorption layer 61 can be formed using a compound semiconductor containing Cd and Te. In this case, the solar battery cell 60 is a CdTe solar battery cell.
  • the light absorption layer 61 is a p-type silicon substrate. Concavities and convexities are formed on the light receiving surface 61 a of the light absorption layer 61. Further, an n-type semiconductor layer 61b formed by diffusing impurities such as phosphorus is provided in the surface region of the light absorption layer 61 on the light receiving surface 61a side. A p + -type semiconductor layer 61c having a high impurity concentration is provided on the side of the light absorption layer 61 opposite to the side on which the n-type semiconductor layer 61b is provided.
  • the electrode 62 is provided so as to cover the p + -type semiconductor layer 61c.
  • the electrode 62 is formed using a conductive material such as aluminum or silver.
  • the electrode 62 becomes a plus (+) electrode.
  • the light absorption layer 61 may be an n-type silicon substrate.
  • a p-type semiconductor layer formed by diffusing impurities such as boron is provided instead of the n-type semiconductor layer 61b.
  • an n + type semiconductor layer having a high impurity concentration is provided.
  • the light absorption layer 61 is an n-type silicon substrate, the conversion efficiency can be increased. In the case where the light absorption layer 61 is a p-type silicon substrate, the manufacturing cost can be reduced.
  • a plurality of grid electrodes 63 are provided on the light receiving surface 61a (on the n-type semiconductor layer 61b).
  • the grid electrode 63 has a linear shape and extends in a direction orthogonal to the direction in which the wiring connection electrode 64 extends.
  • the plurality of grid electrodes 63 are provided over the entire light receiving surface 61a in order to efficiently extract the electric power generated in the light absorption layer 61.
  • the grid electrode 63 is formed using a conductive material such as aluminum or silver, the light incident on the light receiving surface 61 a is blocked by the grid electrode 63. Therefore, it is preferable to make the width dimension of the grid electrode 63 as short as possible.
  • a plurality of wiring connection electrodes 64 are provided on the light receiving surface 61a (on the n-type semiconductor layer 61b).
  • the wiring connection electrode 64 has a linear shape and extends in a direction in which the plurality of solar battery cells 60 are electrically connected in series.
  • the wiring connection electrode 64 has a lower end electrically connected to the n-type semiconductor layer 61 b and an upper end exposed from the antireflection film 65. Further, the wiring connection electrode 64 is electrically connected to the grid electrode 63.
  • the wiring connection electrode 64 is formed using a conductive material such as aluminum or silver.
  • the wiring connection electrode 64 is a negative ( ⁇ ) electrode.
  • the antireflection film 65 is provided so as to cover an exposed portion of the light receiving surface 61a (a region where the grid electrode 63 and the wiring connection electrode 64 are not provided).
  • the antireflection film 65 can be formed from, for example, silicon oxide.
  • the solar battery cell 60 having the above configuration can be manufactured using, for example, a semiconductor manufacturing process.
  • FIG. 7 is a schematic plan view for illustrating connection of a plurality of solar cells 60.
  • 8 is a cross-sectional view taken along line AA in FIG.
  • the plurality of solar cells 60 are electrically connected in series by wiring 66.
  • the output voltage of the power generation unit 6 is (output voltage of the solar battery cell 60) ⁇ (number of connected solar battery cells 60).
  • the output voltage of the crystalline silicon solar cell is generally about 0.65V. Therefore, the output voltage of the power generation unit 6 is set to a desired value by electrically connecting a plurality of solar cells 60 in series. In this case, the output voltage of the power generation unit 6 can be changed by changing the number of connected solar cells 60 or the material of the light absorption layer 61.
  • the power generation unit 4 and the power generation unit 6 are electrically connected in parallel.
  • the sealing part 7 is provided between the protection part 8 and the power generation part 6.
  • the sealing part 7 may be filled also between several photovoltaic cells 60.
  • FIG. The sealing unit 7 seals the side opposite to the light receiving surface side of the power generation unit 6.
  • the sealing unit 7 suppresses, for example, water vapor or gas included in the environment where the solar cell module 1 is installed from reaching the power generation unit 6.
  • the sealing unit 7 joins the protection unit 8 and the power generation unit 6 together.
  • the sealing part 7 can also have a function which absorbs the impact from the outside.
  • the material of the sealing part 7 can be the same as the material of the sealing part 3.
  • the protection unit 8 has a plate shape and faces the protection unit 2.
  • the protection unit 8 is sometimes called a back sheet.
  • the material of the protection part 8 can be the same as the material of the protection part 2. However, unlike the protection unit 2 described above, the protection unit 8 does not need to transmit light. Therefore, the protection part 8 can also be formed from a material with a high reflectance with respect to light.
  • the protection unit 8 can be formed using, for example, a white resin. If the protection part 8 is formed from a material having a high reflectance with respect to light, the light introduced into the solar cell module 1 via the protection part 2 and reaching the protection part 8 is directed toward the power generation part 4 and the power generation part 6. Can be reflected. Therefore, the light use efficiency can be improved.
  • the power generation unit 4 and the power generation unit 6 are electrically connected in parallel. Therefore, the output voltage of the solar cell module 1 is the lower one of the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6. In this case, when the difference between the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 increases, loss may increase and conversion efficiency may decrease.
  • the output voltage of the power generation unit 4 can be changed by changing the material of the light absorption layer 43 or the number of light absorption layers 43 (number of grooves 47).
  • the output voltage of the power generation unit 6 can be changed by changing the number of connected solar cells 60 or the material of the light absorption layer 61. Therefore, the difference between the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 can be reduced by adjusting at least one of the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6.
  • Table 1 is a table for illustrating adjustment of the output voltage in the power generation unit 4 and the power generation unit 6.
  • Table 1 shows a case where the light absorption layer 43 is made of a compound semiconductor containing Cu, In, Ga, and Se and having a high Ga content, and the light absorption layer 61 is made of crystalline silicon.
  • the output voltage of the power generation unit 4 was able to be 19.5 V by changing the number of light absorption layers 43 (number of grooves 47).
  • the output voltage of the power generation unit 6 was able to be 19.5 V by changing the number of connected solar cells 60. That is, by connecting 30 solar cells 60 with an output voltage of 0.65V in series, the output voltage of the power generation unit 6 could be 19.5V.
  • FIG. 9 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
  • A1 in FIG. 9 is a case where the conversion efficiency of the solar cell module 1 is 26%.
  • A2 is a case where the conversion efficiency of the solar cell module 1 is 24%.
  • A3 is a case where the conversion efficiency of the solar cell module 1 is 22%.
  • A4 is a case where the conversion efficiency of the solar cell module 1 is 20%.
  • B is the conversion efficiency of the solar battery cell 60 taking into account the amount of light absorption in the solar battery cell 40.
  • FIG. 9 shows the results obtained by simulation.
  • the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 are assumed to be equal.
  • the solar battery cell 60 was a CIGS solar battery cell.
  • the band gap of the light absorption layer 61 was 1.1 eV.
  • the conversion efficiency of the solar battery cell 60 was 20.0%. If the output voltage of the power generation unit 4 is equal to the output voltage of the power generation unit 6, the same result can be expected even if the material of the light absorption layer 61 is changed.
  • the wavelength region of light incident on the solar battery cell 60 is widened as the band gap of the light absorption layer 43 is increased. . Therefore, as can be seen from B in FIG. 9, the conversion efficiency of the solar battery cell 60 increases as the band gap of the light absorption layer 43 increases. As a result, as can be seen from A1 to A4 in FIG. 9, the conversion efficiency of the solar battery cell 40 required to make the solar battery module 1 having a high conversion efficiency of 20% to 26% decreases. Moreover, when the band gap of the light absorption layer 43 exceeds 1.7 eV, as can be seen from B in FIG. 9, the conversion efficiency of the solar battery cell 60 decreases.
  • the band gap of the light absorption layer 43 is increased, the wavelength region of light incident on the solar cell 60 is widened, so that the conversion efficiency of the solar cell 60 may be increased.
  • the power generation unit 4 and the power generation unit 6 are electrically connected in series, the value of the current flowing through the solar battery cell 40 and the value of the current flowing through the solar battery cell 60 are the same.
  • the band gap of the light absorption layer 43 becomes large, the value of the electric current which flows into the photovoltaic cell 40 becomes small. Therefore, when the band gap of the light absorption layer 43 increases, the value of the current flowing through the solar battery cell 60 decreases. As a result, when the band gap of the light absorption layer 43 exceeds 1.7 eV, the conversion efficiency of the solar battery cell 60 is reduced.
  • FIG. 10 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. In addition, it is the same as that of the case of FIG. 9 except connecting the electric power generation part 4 and the electric power generation part 6 electrically in parallel.
  • the band gap of the light absorption layer 43 is in the range of 1.2 eV to 1.7 eV, the same result as in FIG. 9 is obtained.
  • the band gap of the light absorption layer 43 exceeds 1.7 eV, as can be seen from B in FIG.
  • the conversion efficiency of the solar battery cell 60 further increases. If the power generation unit 4 and the power generation unit 6 are electrically connected in parallel, even if the value of the current flowing through the solar battery cell 40 is reduced, the value of the current flowing through the solar battery cell 60 is not similarly reduced. Therefore, even if the band gap of the light absorption layer 43 exceeds 1.7 eV, the conversion efficiency of the solar battery cell 60 further increases. As a result, as can be seen from A1 to A4 in FIG. 10, the solar cell module 1 required to obtain a high conversion efficiency of 20% to 26% in a wide range of the band gap of the light absorption layer 43 is obtained. The conversion efficiency of the battery cell 40 decreases. This also means that the degree of freedom for designing the solar cell module 1 is increased.
  • FIGS. 11 and 12 are graphs for illustrating the relationship between the conversion efficiency of the solar battery module 1, the region where the conversion efficiency of the solar battery cell 40 is less than the theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. is there.
  • FIG. 11 shows a case where the power generation unit 4 and the power generation unit 6 are electrically connected in series.
  • FIG. 12 shows a case where the power generation unit 4 and the power generation unit 6 are electrically connected in parallel.
  • the region below “1” on the vertical axis is a region where the conversion efficiency of the solar battery cell 40 is less than or equal to the theoretical value. 11 and 12 are compared, the conversion efficiency in the case of FIG.
  • the solar cell module 1 having can be configured. That is, if the power generation unit 4 and the power generation unit 6 are electrically connected in parallel, the solar cell module 1 having high conversion efficiency can be easily obtained. This means that the degree of freedom for designing the solar cell module 1 is increased.
  • the output voltage of the power generation unit 4 can be set by the number of light absorption layers 43 provided in the solar battery cell 40 (the number of grooves 47). Therefore, if one solar battery cell 40 is provided, the effects described in FIGS. 9 to 12 can be obtained.
  • the plurality of light absorption layers 43 are electrically connected in series by the electrode 42 and the electrode 45. Therefore, in the case where the number of the solar battery cells 40 is one, if a part of the electrode 42, the electrode 45, and the light absorption layer 43 is damaged, the power supply from the power generation unit 4 may be stopped.
  • a plurality of solar cells 40 are electrically connected in parallel.
  • the effects described in FIGS. 9 to 12 can be obtained.

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  • Photovoltaic Devices (AREA)

Abstract

The solar cell module according to an embodiment is provided with: a first power generating unit that includes a plurality of first solar cells electrically connected in parallel to one another; and a second power generating unit that includes a plurality of second solar cells electrically connected in series to one another, that is provided on the opposite side of the light incidence side of the first power generating unit, and that is electrically connected in parallel to the first power generating unit. The first solar cells have a plurality of first light absorbing layers electrically connected in series to one another.

Description

太陽電池モジュールSolar cell module

　本発明の実施形態は、太陽電池モジュールに関する。 Embodiment of this invention is related with a solar cell module.

　現在、結晶シリコン太陽電池の変換効率は、理論効率に近い２５．６％に達している。そのため、結晶シリコン太陽電池の変換効率を大幅に向上させることが困難となりつつある。　
　そこで、短波長側の光を吸収する太陽電池セル（トップセル）と、長波長側の光を吸収する太陽電池セル（ボトムセル）とを積み重ねたタンデム構造を有する太陽電池モジュールが提案されている。 Currently, the conversion efficiency of crystalline silicon solar cells has reached 25.6%, which is close to the theoretical efficiency. Therefore, it is becoming difficult to greatly improve the conversion efficiency of the crystalline silicon solar cell.
Therefore, a solar cell module having a tandem structure in which solar cells (top cells) that absorb light on the short wavelength side and solar cells (bottom cells) that absorb light on the long wavelength side are stacked has been proposed.

　一般的なタンデム構造を有する太陽電池モジュールは、同一基板上に、ボトムセルとなる膜と、トップセルとなる膜とを積層させた構造を有している。例えば、シリコン系の太陽電池モジュールは、同一の基板上に、結晶シリコンからなる膜と、非晶質シリコンからなる膜とを積層させた構造を有している。　
　ところが、この様なタンデム構造を有する太陽電池モジュールの変換効率は、例えば、１３．５％程度である。つまり、一般的なタンデム構造を有する太陽電池モジュールの変換効率は、単層の結晶シリコン太陽電池の変換効率よりも低いのが実状である。　
　一般的なタンデム構造を有する太陽電池モジュールの変換効率が低い要因としては、結晶欠陥が多い非晶質シリコンを用いていることがあげられる。 A solar cell module having a general tandem structure has a structure in which a film to be a bottom cell and a film to be a top cell are stacked on the same substrate. For example, a silicon-based solar cell module has a structure in which a film made of crystalline silicon and a film made of amorphous silicon are stacked on the same substrate.
However, the conversion efficiency of the solar cell module having such a tandem structure is, for example, about 13.5%. That is, the conversion efficiency of a solar cell module having a general tandem structure is actually lower than the conversion efficiency of a single-layer crystalline silicon solar cell.
The reason why the conversion efficiency of a solar cell module having a general tandem structure is low is that amorphous silicon having many crystal defects is used.

　そのため、タンデム構造を有し、非晶質シリコンを用いない太陽電池モジュールが提案されている。　
　しかしながら、この様な太陽電池モジュールは、信頼性の向上という観点からは改善の余地がある。 Therefore, a solar cell module having a tandem structure and not using amorphous silicon has been proposed.
However, such a solar cell module has room for improvement from the viewpoint of improving reliability.

特開２０００－２５２４９６号公報JP 2000-252496 A 特開２０１５－６５２４９号公報Japanese Patent Laying-Open No. 2015-65249

　本発明が解決しようとする課題は、信頼性の向上を図ることができる太陽電池モジュールを提供することである。 The problem to be solved by the present invention is to provide a solar cell module capable of improving the reliability.

　実施形態に係る太陽電池モジュールは、電気的に並列接続された複数の第１太陽電池セルを有する第１発電部と、電気的に直列接続された複数の第２太陽電池セルを有し、前記第１発電部の光の入射側とは反対側に設けられ、前記第１発電部と電気的に並列接続された第２発電部と、を備えている。　
　前記第１太陽電池セルは、電気的に直列接続された複数の第１光吸収層を有する。 The solar cell module according to the embodiment includes a first power generation unit having a plurality of first solar cells electrically connected in parallel, and a plurality of second solar cells electrically connected in series, A second power generation unit provided on a side opposite to the light incident side of the first power generation unit and electrically connected in parallel with the first power generation unit.
The first solar cell has a plurality of first light absorption layers electrically connected in series.

本実施の形態に係る太陽電池モジュール１を例示するための模式分解図である。1 is a schematic exploded view for illustrating a solar cell module 1 according to the present embodiment. 太陽電池セル４０を例示するための模式平面図である。4 is a schematic plan view for illustrating a solar battery cell 40. FIG. 太陽電池セル４０を例示するための模式断面図である。3 is a schematic cross-sectional view for illustrating a solar battery cell 40. FIG. 複数の太陽電池セル４０の接続を例示するための模式平面図である。4 is a schematic plan view for illustrating connection of a plurality of solar cells 40. FIG. 太陽電池セル６０を例示するための模式平面図である。3 is a schematic plan view for illustrating a solar battery cell 60. FIG. （ａ）、（ｂ）は、太陽電池セル６０を例示するための模式断面図である。(A), (b) is a schematic cross section for illustrating the photovoltaic cell 60. FIG. 複数の太陽電池セル６０の接続を例示するための模式平面図である。4 is a schematic plan view for illustrating connection of a plurality of solar cells 60. FIG. 図７におけるＡ－Ａ線断面図である。FIG. 8 is a cross-sectional view taken along line AA in FIG. 太陽電池セル４０の変換効率と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。FIG. 6 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. 太陽電池セル４０の変換効率と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。FIG. 6 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. 太陽電池セル４０の変換効率が理論値以下となる領域と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。4 is a graph for illustrating the relationship between a region where the conversion efficiency of the solar battery cell 40 is less than or equal to a theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. FIG. 太陽電池セル４０の変換効率が理論値以下となる領域と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。4 is a graph for illustrating the relationship between a region where the conversion efficiency of the solar battery cell 40 is less than or equal to a theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. FIG.

　以下、図面を参照しつつ、実施の形態について例示をする。なお、各図面中、同様の構成要素には同一の符号を付して詳細な説明は適宜省略する。 Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

　図１は、本実施の形態に係る太陽電池モジュール１を例示するための模式分解図である。　
　図１に示すように、太陽電池モジュール１には、保護部２、封止部３、発電部４（第１発電部の一例に相当する）、絶縁部５、発電部６（第２発電部の一例に相当する）、封止部７、および保護部８が設けられている。 FIG. 1 is a schematic exploded view for illustrating a solar cell module 1 according to the present embodiment.
As shown in FIG. 1, the solar cell module 1 includes a protection unit 2, a sealing unit 3, a power generation unit 4 (corresponding to an example of a first power generation unit), an insulating unit 5, and a power generation unit 6 (second power generation unit). The sealing part 7 and the protection part 8 are provided.

　保護部２は、板状を呈し、発電部４および発電部６の受光面側（光Ｌの入射面側）に設けられている。　
　保護部２は、太陽光などの光Ｌを透過させるとともに、発電部４および発電部６の受光面側を保護する。　
　保護部２は、例えば、ガラスなどの無機材料や透光性樹脂などの有機材料を用いて形成することができる。　
　ガラスなどの無機材料は、例えば、無アルカリガラス、石英ガラス、アルカリ金属を含むガラスなどとすることができる。　
　アルカリ金属を含むガラスは、例えば、ソーダライムガラス（soda-lime glass）などとすることができる。　
　ここで、後述する太陽電池セル４０（第１太陽電池セルの一例に相当する）や太陽電池セル６０（第２太陽電池セルの一例に相当する）がＣＩＧＳ系の太陽電池セルとされる場合がある。　
　ＣＩＧＳ系の太陽電池セルは、Ｃｕ（Ｉｎ、Ｇａ）Ｓｅ２を含んでいる。　
　そのため、ＣＩＧＳ系の太陽電池セルにおいては、Ｃｕが拡散して、Ｃｕの欠損が生じる場合がある。　
　保護部２がアルカリ金属を含むガラスから形成されると、アルカリ金属を含むガラスに含まれているアルカリ金属イオン（例えば、ＮａイオンやＫイオンなど）が、置換によりＣｕの欠損部分に入り込む。　
　アルカリ金属イオンが、Ｃｕの欠損部分に入り込むと、開放電圧が増加し、ひいては変換効率を高めることができる。　
　そのため、太陽電池セル４０、および太陽電池セル６０の少なくともいずれかがＣＩＧＳ系の太陽電池セルとされる場合には、保護部２は、ソーダライムガラスなどのアルカリ金属を含むガラスから形成することが好ましい。
　透光性樹脂などの有機材料は、例えば、ポリエチレン、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリイミド、ポリアミド、ポリアミドイミド、液晶ポリマー、シクロオレフィンポリマーなどとすることができる。　
　この場合、保護部２は、透湿性の低い無機材料から形成するのが好ましい。 The protection unit 2 has a plate shape, and is provided on the light receiving surface side (incident surface side of the light L) of the power generation unit 4 and the power generation unit 6.
The protection unit 2 transmits light L such as sunlight and protects the light receiving surface sides of the power generation unit 4 and the power generation unit 6.
The protection unit 2 can be formed using, for example, an inorganic material such as glass or an organic material such as a translucent resin.
The inorganic material such as glass can be, for example, non-alkali glass, quartz glass, glass containing an alkali metal, or the like.
The glass containing an alkali metal can be, for example, soda-lime glass.
Here, a solar battery cell 40 (corresponding to an example of a first solar battery cell) or a solar battery cell 60 (corresponding to an example of a second solar battery cell) described later may be a CIGS solar battery cell. is there.
The CIGS solar cell includes Cu (In, Ga) Se 2 .
Therefore, in a CIGS solar cell, Cu diffuses and Cu defects may occur.
When the protective part 2 is formed of glass containing an alkali metal, alkali metal ions (for example, Na ions, K ions, etc.) contained in the glass containing the alkali metal enter the Cu deficient portion by substitution.
When alkali metal ions enter the defect portion of Cu, the open circuit voltage increases, and as a result, the conversion efficiency can be increased.
Therefore, when at least one of the solar battery cell 40 and the solar battery cell 60 is a CIGS solar battery cell, the protection unit 2 may be formed of glass containing an alkali metal such as soda lime glass. preferable.
The organic material such as a translucent resin can be, for example, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamideimide, liquid crystal polymer, cycloolefin polymer, or the like.
In this case, the protection part 2 is preferably formed from an inorganic material having low moisture permeability.

　封止部３は、保護部２と発電部４の間に設けられている。　
　なお、封止部３は、後述する複数の太陽電池セル４０同士の間にも充填されていてもよい。　
　封止部３は、発電部４の受光面側を封止する。　
　封止部３は、例えば、太陽電池モジュール１を設置する環境に含まれる水蒸気やガスなどが発電部４に到達するのを抑制する。　
　封止部３は、封止部３に入射した光を透過させる。　
　封止部３は、保護部２と発電部４を接合する。　
　封止部３は、外部からの衝撃を吸収する機能を有するものとすることもできる。
　封止部３は、例えば、エチレン・酢酸ビニル共重合体（EVA：ethylene-vinylacetate copolymer）、ＰＶＢ（polyvinyl butyral）、アイオノマー(ionomer)などから形成することができる。 The sealing unit 3 is provided between the protection unit 2 and the power generation unit 4.
In addition, the sealing part 3 may be filled also between several photovoltaic cells 40 mentioned later.
The sealing unit 3 seals the light receiving surface side of the power generation unit 4.
The sealing unit 3 suppresses, for example, water vapor or gas included in the environment where the solar cell module 1 is installed from reaching the power generation unit 4.
The sealing unit 3 transmits light incident on the sealing unit 3.
The sealing unit 3 joins the protection unit 2 and the power generation unit 4 together.
The sealing part 3 can also have the function to absorb the impact from the outside.
The sealing part 3 can be formed from, for example, ethylene-vinyl acetate copolymer (EVA), PVB (polyvinyl butyral), ionomer, or the like.

　発電部４は、保護部２の光Ｌが入射する側とは反対側に設けられている。
　発電部４は、複数の太陽電池セル４０、および複数の太陽電池セル４０を電気的に並列接続する配線４６を有する。　
　太陽電池セル４０は、入射した光Ｌのうち、主に短波長の光を吸収して電力に変換する。　
　なお、入射した光Ｌのうち長波長の光は、太陽電池セル４０を透過して後述する太陽電池セル６０に入射する。　
　そのため、太陽電池セル４０（光吸収層４３（第１光吸収層の一例に相当する））は、太陽電池セル６０（光吸収層６１（第２光吸収層の一例に相当する））が有するバンドギャップよりも大きなバンドギャップを有する。　
　例えば、太陽電池セル４０をＧａの含有量が多いＣＩＧＳ系の太陽電池セルなどとし、太陽電池セル６０を結晶シリコン太陽電池セルなどとすることができる。
　なお、太陽電池セル４０および太陽電池セル６０に関する詳細は後述する。 The power generation unit 4 is provided on the side opposite to the side on which the light L of the protection unit 2 is incident.
The power generation unit 4 includes a plurality of solar cells 40 and wirings 46 that electrically connect the plurality of solar cells 40 in parallel.
The solar battery cell 40 mainly absorbs light having a short wavelength in the incident light L and converts it into electric power.
Of the incident light L, long wavelength light passes through the solar battery cell 40 and enters the solar battery cell 60 described later.
Therefore, the solar battery cell 40 (light absorption layer 43 (corresponding to an example of the first light absorption layer)) is included in the solar battery cell 60 (light absorption layer 61 (corresponding to an example of the second light absorption layer)). It has a larger band gap than the band gap.
For example, the solar battery cell 40 can be a CIGS solar battery cell having a high Ga content, and the solar battery cell 60 can be a crystalline silicon solar battery cell.
In addition, the detail regarding the photovoltaic cell 40 and the photovoltaic cell 60 is mentioned later.

　図２は、太陽電池セル４０を例示するための模式平面図である。　
　図３は、太陽電池セル４０を例示するための模式断面図である。　
　図２および図３に示すように、太陽電池セル４０は、複数の光吸収層４３が電気的に直列接続されたモノリシック集積構造を有している。　
　太陽電池セル４０は、基板４１、電極４２、光吸収層４３、バッファ層４４、および電極４５を有する。 FIG. 2 is a schematic plan view for illustrating the solar battery cell 40.
FIG. 3 is a schematic cross-sectional view for illustrating the solar battery cell 40.
As shown in FIGS. 2 and 3, the solar battery cell 40 has a monolithic integrated structure in which a plurality of light absorption layers 43 are electrically connected in series.
The solar battery cell 40 includes a substrate 41, an electrode 42, a light absorption layer 43, a buffer layer 44, and an electrode 45.

　基板４１は、板状を呈し、光吸収層４３において吸収されなかった光を透過させる。　
　基板４１は、例えば、保護部２と同じ材料から形成することができる。 The substrate 41 has a plate shape and transmits light that has not been absorbed by the light absorption layer 43.
The substrate 41 can be formed from the same material as that of the protection unit 2, for example.

　電極４２は、基板４１の一方の表面に設けられている。　
　電極４２は、所定の間隔を空けて複数設けられている。　
　電極４２の一方の端部側には光吸収層４３が電気的に接続され、電極４２の他方の端部側には隣接する光吸収層４３が電気的に接続されている。　
　電極４２は、透光性と導電性を有する材料から形成されている。　
　電極４２は、例えば、ＩＴＯやＺｎＯなどの透明電極材料を用いて形成することができる。 The electrode 42 is provided on one surface of the substrate 41.
A plurality of electrodes 42 are provided at a predetermined interval.
The light absorption layer 43 is electrically connected to one end side of the electrode 42, and the adjacent light absorption layer 43 is electrically connected to the other end side of the electrode 42.
The electrode 42 is formed from a material having translucency and conductivity.
The electrode 42 can be formed using, for example, a transparent electrode material such as ITO or ZnO.

　光吸収層４３は、電極４２の基板４１側とは反対側に設けられている。　
　光吸収層４３は、所定の間隔を空けて複数設けられている。　
　また、光吸収層４３は、所定の間隔を空けて設けられた電極４２の間を跨ぐように設けられている。　
　光吸収層４３は、入射した光Ｌのうち、主に短波長の光を吸収して電力に変換する。 The light absorption layer 43 is provided on the opposite side of the electrode 42 from the substrate 41 side.
A plurality of light absorption layers 43 are provided with a predetermined interval.
The light absorption layer 43 is provided so as to straddle between the electrodes 42 provided at a predetermined interval.
The light absorption layer 43 mainly absorbs short wavelength light in the incident light L and converts it into electric power.

　ここで、太陽電池セル４０と太陽電池セル６０とを協働させて発電を行うことを考慮すると、光吸収層４３はバンドギャップがなるべく大きな材料を用いて形成することが好ましい。　
　例えば、光吸収層４３は、バンドギャップが１．４ｅＶ以上、３．０ｅＶ以下の材料を用いて形成することが好ましい。　
　例えば、光吸収層４３は、Ｃｕ、Ｉｎ、Ｇａ、およびＳｅを含み、且つ、Ｇａの含有量が多い化合物半導体を用いて形成することができる。　
　この場合、太陽電池セル４０は、Ｇａの含有量が多いＣＩＧＳ系の太陽電池セルとなる。 Here, considering that power generation is performed with the solar battery cell 40 and the solar battery cell 60 cooperating, it is preferable to form the light absorption layer 43 using a material having as large a band gap as possible.
For example, the light absorption layer 43 is preferably formed using a material having a band gap of 1.4 eV or more and 3.0 eV or less.
For example, the light absorption layer 43 can be formed using a compound semiconductor containing Cu, In, Ga, and Se and having a high Ga content.
In this case, the solar battery cell 40 is a CIGS solar battery cell with a high Ga content.

　光吸収層４３は、Ｃｕ、Ｚｎ、Ｓｎ、Ｓ、およびＳｅを含む化合物半導体を用いて形成することができる。　
　この場合、太陽電池セル４０は、ＣＺＴＳ系の太陽電池セルとなる。　
　光吸収層４３は、ｐ形の有機半導体材料からなる層と、ｎ形の有機半導体材料からなる層とを有したものとすることができる。　
　この場合、太陽電池セル４０は、有機薄膜系の太陽電池セルとなる。　
　光吸収層４３は、ペロブスカイト結晶構造を有する材料を用いて形成することができる。　
　この場合、太陽電池セル４０は、ペロブスカイト系の太陽電池セルとなる。 The light absorption layer 43 can be formed using a compound semiconductor containing Cu, Zn, Sn, S, and Se.
In this case, the solar cell 40 is a CZTS solar cell.
The light absorption layer 43 may have a layer made of a p-type organic semiconductor material and a layer made of an n-type organic semiconductor material.
In this case, the solar cell 40 is an organic thin film solar cell.
The light absorption layer 43 can be formed using a material having a perovskite crystal structure.
In this case, the solar cell 40 is a perovskite solar cell.

　バッファ層４４は、光吸収層４３の電極４２側とは反対側に設けられている。　バッファ層４４は、ｎ形半導体から形成されている。　
　光吸収層４３を成膜する際に低抵抗の不純物が生成されると、リーク電流が発生して変換効率が低下するおそれがある。　
　そのため、ｐ形半導体からなる光吸収層４３の上に、ｎ形半導体からなるバッファ層４４を設けることで不純物に起因するリーク電流を抑制する様にしている。　バッファ層４４は、例えば、ＣｄＳやＺｎＳなどから形成することができる。 The buffer layer 44 is provided on the opposite side of the light absorption layer 43 from the electrode 42 side. The buffer layer 44 is made of an n-type semiconductor.
If low-resistance impurities are generated when the light absorption layer 43 is formed, a leakage current may be generated and conversion efficiency may be reduced.
For this reason, a buffer layer 44 made of an n-type semiconductor is provided on the light absorption layer 43 made of a p-type semiconductor to suppress leakage current caused by impurities. The buffer layer 44 can be formed from, for example, CdS, ZnS, or the like.

　電極４５は、バッファ層４４の光吸収層４３側とは反対側に設けられている。　電極４５は、透光性と導電性を有する材料から形成されている。　
　電極４５は、例えば、電極４２と同じ材料から形成することができる。　
　また、電極４５は、光吸収層４３を厚み方向に貫通し、電極４２に電気的に接続されている。　
　すなわち、図３に示すように、複数の光吸収層４３が、電極４２および電極４５により電気的に直列接続されている。 The electrode 45 is provided on the opposite side of the buffer layer 44 from the light absorption layer 43 side. The electrode 45 is formed from a material having translucency and conductivity.
The electrode 45 can be formed from the same material as the electrode 42, for example.
The electrode 45 penetrates the light absorption layer 43 in the thickness direction and is electrically connected to the electrode 42.
That is, as shown in FIG. 3, the plurality of light absorption layers 43 are electrically connected in series by the electrode 42 and the electrode 45.

　複数の光吸収層４３が直列接続されているので、太陽電池セル４０は高電圧タイプの太陽電池セルとなる。　
　また、太陽電池セル４０の出力電圧は、光吸収層４３の材料と光吸収層４３の数（溝４７の数）を変えることで変更することが可能となる。　
　以上の様な構成を有する太陽電池セル４０は、例えば、半導体製造プロセスを用いて製造することができる。　
　この場合、レーザなどを用いたスクライビング（溝加工）を行うことで、光吸収層４３などを分割することができる。 Since the several light absorption layer 43 is connected in series, the photovoltaic cell 40 turns into a high voltage type photovoltaic cell.
Further, the output voltage of the solar battery cell 40 can be changed by changing the material of the light absorption layer 43 and the number of light absorption layers 43 (number of grooves 47).
The solar battery cell 40 having the above configuration can be manufactured using, for example, a semiconductor manufacturing process.
In this case, the light absorption layer 43 and the like can be divided by performing scribing (grooving) using a laser or the like.

　図４は、複数の太陽電池セル４０の接続を例示するための模式平面図である。　図４に示すように、複数の太陽電池セル４０は、配線４６により電気的に並列接続されている。　
　そのため、発電部４の出力電圧は、太陽電池セル４０の出力電圧と同じとなる。　前述したように、太陽電池セル４０の出力電圧は、光吸収層４３の材料または光吸収層４３の数（溝４７の数）を変えることで変更することができる。　
　そのため、太陽電池セル４０の出力電圧を変更することで、発電部４の出力電圧を変更することができる。 FIG. 4 is a schematic plan view for illustrating the connection of a plurality of solar cells 40. As shown in FIG. 4, the plurality of solar cells 40 are electrically connected in parallel by wiring 46.
Therefore, the output voltage of the power generation unit 4 is the same as the output voltage of the solar battery cell 40. As described above, the output voltage of the solar battery cell 40 can be changed by changing the material of the light absorption layer 43 or the number of light absorption layers 43 (number of grooves 47).
Therefore, the output voltage of the power generation unit 4 can be changed by changing the output voltage of the solar battery cell 40.

　図１に示すように、絶縁部５は、発電部４と発電部６の間に設けられている。　絶縁部５は、発電部４と発電部６の間を絶縁する。　
　絶縁部５は、絶縁部５に入射した光を透過させる。　
　絶縁部５は、発電部４と発電部６を接合する。　
　そのため、絶縁部５は、透光性および絶縁性を有し、接合機能をも有している。　絶縁部５は、例えば、無アルカリガラスや石英ガラスなどからなる基板の表面に、アクリル系樹脂からなる接着層を設けたものとすることができる。 As shown in FIG. 1, the insulating unit 5 is provided between the power generation unit 4 and the power generation unit 6. The insulating unit 5 insulates between the power generation unit 4 and the power generation unit 6.
The insulating unit 5 transmits light incident on the insulating unit 5.
The insulating unit 5 joins the power generation unit 4 and the power generation unit 6.
Therefore, the insulation part 5 has translucency and insulation, and also has a joining function. The insulating part 5 can be provided with an adhesive layer made of an acrylic resin on the surface of a substrate made of alkali-free glass or quartz glass, for example.

　発電部６は、発電部４の光の入射側とは反対側に設けられている。　
　発電部６は、絶縁部５を介して発電部４と対峙している。　
　すなわち、太陽電池モジュール１は、短波長側の光を吸収する発電部４（トップセル）と、長波長側の光を吸収する発電部６（ボトムセル）とを積み重ねたタンデム構造を有している。　
　発電部６は、複数の太陽電池セル６０と、複数の太陽電池セル６０を電気的に直列接続する配線６６を有する。　
　太陽電池セル６０は、太陽電池セル４０を透過した光（主に長波長の光）を吸収して電力に変換する。 The power generation unit 6 is provided on the side opposite to the light incident side of the power generation unit 4.
The power generation unit 6 is opposed to the power generation unit 4 via the insulating unit 5.
That is, the solar cell module 1 has a tandem structure in which a power generation unit 4 (top cell) that absorbs light on the short wavelength side and a power generation unit 6 (bottom cell) that absorbs light on the long wavelength side are stacked. .
The power generation unit 6 includes a plurality of solar cells 60 and a wiring 66 that electrically connects the plurality of solar cells 60 in series.
The solar battery cell 60 absorbs light (mainly long wavelength light) transmitted through the solar battery cell 40 and converts it into electric power.

　図５は、太陽電池セル６０を例示するための模式平面図である。　
　なお、図５においては、煩雑となるのを避けるために反射防止膜６５を省いて描いている。　
　図６（ａ）、（ｂ）は、太陽電池セル６０を例示するための模式断面図である。　図６（ａ）は、図５におけるＡ－Ａ線断面図である。　
　図６（ｂ）は、図５におけるＢ－Ｂ線断面図である。　
　図５、図６（ａ）、および図６（ｂ）に示すように、太陽電池セル６０は、グリッド型構造を有している。　
　太陽電池セル６０には、光吸収層６１、電極６２、グリッド電極６３、配線接続電極６４、および反射防止膜６５が設けられている。 FIG. 5 is a schematic plan view for illustrating the solar battery cell 60.
In FIG. 5, the antireflection film 65 is omitted in order to avoid complication.
FIGS. 6A and 6B are schematic cross-sectional views for illustrating the solar battery cell 60. FIG. 6A is a cross-sectional view taken along line AA in FIG.
FIG. 6B is a cross-sectional view taken along line BB in FIG.
As shown in FIGS. 5, 6 (a), and 6 (b), the solar battery cell 60 has a grid type structure.
The solar cell 60 is provided with a light absorption layer 61, an electrode 62, a grid electrode 63, a wiring connection electrode 64, and an antireflection film 65.

　光吸収層６１は、光吸収層４３のバンドギャップよりも小さいバンドギャップを有する。　
　光吸収層６１は、バンドギャップが１．０ｅＶ以上、１．４ｅＶ以下の材料を用いて形成することが好ましい。　
　例えば、光吸収層６１は、単結晶シリコン、多結晶シリコン、微結晶シリコンなどの結晶シリコンを用いて形成することができる。　
　この場合、太陽電池セル６０は、結晶シリコン太陽電池セルとなる。 The light absorption layer 61 has a band gap smaller than that of the light absorption layer 43.
The light absorption layer 61 is preferably formed using a material having a band gap of 1.0 eV or more and 1.4 eV or less.
For example, the light absorption layer 61 can be formed using crystalline silicon such as single crystal silicon, polycrystalline silicon, or microcrystalline silicon.
In this case, the solar battery cell 60 is a crystalline silicon solar battery cell.

　光吸収層６１は、Ｃｕ、Ｉｎ、Ｇａ、およびＳｅを含み、且つ、Ｉｎの含有量が多い化合物半導体を用いて形成することができる。　
　この場合、太陽電池セル６０は、Ｉｎの含有量が多いＣＩＧＳ系の太陽電池セルとなる。　
　光吸収層６１は、ＣｕＩｎＴｅ２（ＣＩＴ）を用いて形成することができる。　この場合、太陽電池セル６０は、ＣＩＴ系の太陽電池セルとなる。　
　光吸収層６１は、ＣｄおよびＴｅを含む化合物半導体を用いて形成することができる。　
　この場合、太陽電池セル６０は、ＣｄＴｅ系の太陽電池セルとなる。 The light absorption layer 61 can be formed using a compound semiconductor containing Cu, In, Ga, and Se and having a high In content.
In this case, the solar battery cell 60 is a CIGS solar battery cell having a large In content.
The light absorption layer 61 can be formed using CuInTe 2 (CIT). In this case, the solar battery cell 60 is a CIT solar battery cell.
The light absorption layer 61 can be formed using a compound semiconductor containing Cd and Te.
In this case, the solar battery cell 60 is a CdTe solar battery cell.

　以下においては、一例として、光吸収層６１が結晶シリコンからなる場合を説明する。　
　光吸収層６１は、ｐ形シリコン基板である。　
　光吸収層６１の受光面６１ａには、凹凸が形成されている。　
　また、光吸収層６１の受光面６１ａ側の表面領域には、リンなどの不純物を拡散させることで形成されたｎ形半導体層６１ｂが設けられている。　
　光吸収層６１のｎ形半導体層６１ｂが設けられる側とは反対側には、不純物の濃度が高いｐ＋形半導体層６１ｃが設けられている。　
　電極６２は、ｐ＋形半導体層６１ｃを覆うように設けられている。電極６２は、アルミニウムや銀などの導電性材料を用いて形成されている。　
　電極６２は、プラス（＋）電極となる。　
　なお、以上においては、光吸収層６１がｐ形シリコン基板である場合を例示したが、光吸収層６１はｎ形シリコン基板であってもよい。　
　光吸収層６１がｎ形シリコン基板である場合には、ｎ形半導体層６１ｂに代えて、ボロンなどの不純物を拡散させることで形成されたｐ形半導体層が設けられる。また、ｐ＋形半導体層６１ｃに代えて、不純物の濃度が高いｎ＋形半導体層が設けられる。　
　光吸収層６１がｎ形シリコン基板である場合には、変換効率を高めることができる。　
　光吸収層６１がｐ形シリコン基板である場合には、製造コストの低減を図ることができる。 In the following, a case where the light absorption layer 61 is made of crystalline silicon will be described as an example.
The light absorption layer 61 is a p-type silicon substrate.
Concavities and convexities are formed on the light receiving surface 61 a of the light absorption layer 61.
Further, an n-type semiconductor layer 61b formed by diffusing impurities such as phosphorus is provided in the surface region of the light absorption layer 61 on the light receiving surface 61a side.
A p + -type semiconductor layer 61c having a high impurity concentration is provided on the side of the light absorption layer 61 opposite to the side on which the n-type semiconductor layer 61b is provided.
The electrode 62 is provided so as to cover the p + -type semiconductor layer 61c. The electrode 62 is formed using a conductive material such as aluminum or silver.
The electrode 62 becomes a plus (+) electrode.
In addition, although the case where the light absorption layer 61 was a p-type silicon substrate was illustrated above, the light absorption layer 61 may be an n-type silicon substrate.
When the light absorption layer 61 is an n-type silicon substrate, a p-type semiconductor layer formed by diffusing impurities such as boron is provided instead of the n-type semiconductor layer 61b. Further, instead of the p + type semiconductor layer 61c, an n + type semiconductor layer having a high impurity concentration is provided.
When the light absorption layer 61 is an n-type silicon substrate, the conversion efficiency can be increased.
In the case where the light absorption layer 61 is a p-type silicon substrate, the manufacturing cost can be reduced.

　グリッド電極６３は、受光面６１ａの上（ｎ形半導体層６１ｂの上）に複数設けられている。　
　グリッド電極６３は、線状を呈し、配線接続電極６４が延びる方向と直交する方向に延びている。　
　複数のグリッド電極６３は、光吸収層６１において生じた電力を効率よく取り出すために受光面６１ａの全域に設けられている。　
　ここで、グリッド電極６３は、アルミニウムや銀などの導電性材料を用いて形成されているので、受光面６１ａに入射する光がグリッド電極６３により遮られる。　
　そのため、グリッド電極６３の幅寸法は、できるだけ短くなるようにすることが好ましい。 A plurality of grid electrodes 63 are provided on the light receiving surface 61a (on the n-type semiconductor layer 61b).
The grid electrode 63 has a linear shape and extends in a direction orthogonal to the direction in which the wiring connection electrode 64 extends.
The plurality of grid electrodes 63 are provided over the entire light receiving surface 61a in order to efficiently extract the electric power generated in the light absorption layer 61.
Here, since the grid electrode 63 is formed using a conductive material such as aluminum or silver, the light incident on the light receiving surface 61 a is blocked by the grid electrode 63.
Therefore, it is preferable to make the width dimension of the grid electrode 63 as short as possible.

　配線接続電極６４は、受光面６１ａの上（ｎ形半導体層６１ｂの上）に複数設けられている。　
　配線接続電極６４は、線状を呈し、複数の太陽電池セル６０を電気的に直列接続する方向に延びている。　
　配線接続電極６４は、下端がｎ形半導体層６１ｂに電気的に接続され、上端が反射防止膜６５から露出している。また、配線接続電極６４は、グリッド電極６３に電気的に接続されている。　
　配線接続電極６４は、アルミニウムや銀などの導電性材料を用いて形成されている。　
　配線接続電極６４は、マイナス（－）電極となる。 A plurality of wiring connection electrodes 64 are provided on the light receiving surface 61a (on the n-type semiconductor layer 61b).
The wiring connection electrode 64 has a linear shape and extends in a direction in which the plurality of solar battery cells 60 are electrically connected in series.
The wiring connection electrode 64 has a lower end electrically connected to the n-type semiconductor layer 61 b and an upper end exposed from the antireflection film 65. Further, the wiring connection electrode 64 is electrically connected to the grid electrode 63.
The wiring connection electrode 64 is formed using a conductive material such as aluminum or silver.
The wiring connection electrode 64 is a negative (−) electrode.

　反射防止膜６５は、受光面６１ａの露出部分（グリッド電極６３および配線接続電極６４が設けられていない領域）を覆うように設けられている。反射防止膜６５は、例えば、シリコン酸化物などから形成することができる。
　以上の様な構成を有する太陽電池セル６０は、例えば、半導体製造プロセスを用いて製造することができる。 The antireflection film 65 is provided so as to cover an exposed portion of the light receiving surface 61a (a region where the grid electrode 63 and the wiring connection electrode 64 are not provided). The antireflection film 65 can be formed from, for example, silicon oxide.
The solar battery cell 60 having the above configuration can be manufactured using, for example, a semiconductor manufacturing process.

　図７は、複数の太陽電池セル６０の接続を例示するための模式平面図である。　図８は、図７におけるＡ－Ａ線断面図である。　
　図７および図８に示すように、複数の太陽電池セル６０は、配線６６により電気的に直列接続されている。　
　この場合、発電部６の出力電圧は、（太陽電池セル６０の出力電圧）×（太陽電池セル６０の接続数）となる。　
　結晶シリコン太陽電池セルの出力電圧は、一般的には、０．６５V程度である。　
　そのため、複数の太陽電池セル６０を電気的に直列接続することで、発電部６の出力電圧が所望の値となるようにしている。　
　この場合、太陽電池セル６０の接続数または光吸収層６１の材料を変更することで、発電部６の出力電圧を変更することができる。　
　また、発電部４と発電部６は、電気的に並列接続される。 FIG. 7 is a schematic plan view for illustrating connection of a plurality of solar cells 60. 8 is a cross-sectional view taken along line AA in FIG.
As shown in FIGS. 7 and 8, the plurality of solar cells 60 are electrically connected in series by wiring 66.
In this case, the output voltage of the power generation unit 6 is (output voltage of the solar battery cell 60) × (number of connected solar battery cells 60).
The output voltage of the crystalline silicon solar cell is generally about 0.65V.
Therefore, the output voltage of the power generation unit 6 is set to a desired value by electrically connecting a plurality of solar cells 60 in series.
In this case, the output voltage of the power generation unit 6 can be changed by changing the number of connected solar cells 60 or the material of the light absorption layer 61.
The power generation unit 4 and the power generation unit 6 are electrically connected in parallel.

　図１に示すように、封止部７は、保護部８と発電部６の間に設けられている。　なお、封止部７は、複数の太陽電池セル６０同士の間にも充填されていてもよい。　
　封止部７は、発電部６の受光面側とは反対側を封止する。　
　封止部７は、例えば、太陽電池モジュール１を設置する環境に含まれる水蒸気やガスなどが発電部６に到達するのを抑制する。　
　封止部７は、保護部８と発電部６を接合する。　
　また、封止部７は、外部からの衝撃を吸収する機能を有するものとすることもできる。　
　封止部７の材料は、封止部３の材料と同様とすることができる。 As shown in FIG. 1, the sealing part 7 is provided between the protection part 8 and the power generation part 6. In addition, the sealing part 7 may be filled also between several photovoltaic cells 60. FIG.
The sealing unit 7 seals the side opposite to the light receiving surface side of the power generation unit 6.
The sealing unit 7 suppresses, for example, water vapor or gas included in the environment where the solar cell module 1 is installed from reaching the power generation unit 6.
The sealing unit 7 joins the protection unit 8 and the power generation unit 6 together.
Moreover, the sealing part 7 can also have a function which absorbs the impact from the outside.
The material of the sealing part 7 can be the same as the material of the sealing part 3.

　保護部８は、板状を呈し、保護部２と対峙している。　
　保護部８は、バックシートと呼ばれることもある。　
　保護部８の材料は、保護部２の材料と同様とすることができる。　
　ただし、保護部８は、前述した保護部２とは異なり、光を透過させる必要はない。そのため、保護部８は、光に対する反射率の高い材料から形成することもできる。保護部８は、例えば、白色の樹脂を用いて形成することができる。光に対する反射率の高い材料から保護部８を形成すれば、保護部２を介して太陽電池モジュール１の内部に導入され、保護部８に到達した光を発電部４および発電部６に向けて反射させることができる。そのため、光の利用効率を向上させることができる。 The protection unit 8 has a plate shape and faces the protection unit 2.
The protection unit 8 is sometimes called a back sheet.
The material of the protection part 8 can be the same as the material of the protection part 2.
However, unlike the protection unit 2 described above, the protection unit 8 does not need to transmit light. Therefore, the protection part 8 can also be formed from a material with a high reflectance with respect to light. The protection unit 8 can be formed using, for example, a white resin. If the protection part 8 is formed from a material having a high reflectance with respect to light, the light introduced into the solar cell module 1 via the protection part 2 and reaching the protection part 8 is directed toward the power generation part 4 and the power generation part 6. Can be reflected. Therefore, the light use efficiency can be improved.

　前述したように、発電部４と発電部６は、電気的に並列接続される。　
　そのため、太陽電池モジュール１の出力電圧は、発電部４の出力電圧と発電部６の出力電圧のうち、いずれか低い方になる。　
　この場合、発電部４の出力電圧と発電部６の出力電圧との差が大きくなると、ロスが大きくなり変換効率が低下するおそれがある。　
　前述したように、発電部４の出力電圧は、光吸収層４３の材料または光吸収層４３の数（溝４７の数）を変えることで変更することができる。　
　発電部６の出力電圧は、太陽電池セル６０の接続数または光吸収層６１の材料を変えることで変更することができる。　
　そのため、発電部４の出力電圧、および発電部６の出力電圧の少なくともいずれかを調整することで、発電部４の出力電圧と発電部６の出力電圧との差を小さくすることができる。 As described above, the power generation unit 4 and the power generation unit 6 are electrically connected in parallel.
Therefore, the output voltage of the solar cell module 1 is the lower one of the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6.
In this case, when the difference between the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 increases, loss may increase and conversion efficiency may decrease.
As described above, the output voltage of the power generation unit 4 can be changed by changing the material of the light absorption layer 43 or the number of light absorption layers 43 (number of grooves 47).
The output voltage of the power generation unit 6 can be changed by changing the number of connected solar cells 60 or the material of the light absorption layer 61.
Therefore, the difference between the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 can be reduced by adjusting at least one of the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6.

　表１は、発電部４および発電部６における出力電圧の調整を例示するための表である。　

Figure JPOXMLDOC01-appb-T000001

　なお、表１は、光吸収層４３が、Ｃｕ、Ｉｎ、Ｇａ、およびＳｅを含み、且つ、Ｇａの含有量が多い化合物半導体からなり、光吸収層６１が、結晶シリコンからなる場合である。　
　表１に示すように、発電部４の出力電圧は、光吸収層４３の数（溝４７の数）を変えることで、１９．５Ｖとなるようにできた。　
　表１に示すように、発電部６の出力電圧は、太陽電池セル６０の接続数を変えることで、１９．５Ｖとなるようにできた。　
　すなわち、出力電圧が０．６５Ｖの太陽電池セル６０を３０個直列接続することで、発電部６の出力電圧が１９．５Ｖとなるようにできた。 Table 1 is a table for illustrating adjustment of the output voltage in the power generation unit 4 and the power generation unit 6.
Figure JPOXMLDOC01-appb-T000001
Table 1 shows a case where the light absorption layer 43 is made of a compound semiconductor containing Cu, In, Ga, and Se and having a high Ga content, and the light absorption layer 61 is made of crystalline silicon.
As shown in Table 1, the output voltage of the power generation unit 4 was able to be 19.5 V by changing the number of light absorption layers 43 (number of grooves 47).
As shown in Table 1, the output voltage of the power generation unit 6 was able to be 19.5 V by changing the number of connected solar cells 60.
That is, by connecting 30 solar cells 60 with an output voltage of 0.65V in series, the output voltage of the power generation unit 6 could be 19.5V.

　次に、発電部４と発電部６を電気的に並列接続した場合の効果について説明する。　
　まず、比較例として、発電部４と発電部６を電気的に直列接続した場合について説明する。　
　図９は、太陽電池セル４０の変換効率と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。　
　図９中のＡ１は、太陽電池モジュール１の変換効率が２６％の場合である。　
　Ａ２は、太陽電池モジュール１の変換効率が２４％の場合である。　
　Ａ３は、太陽電池モジュール１の変換効率が２２％の場合である。　
　Ａ４は、太陽電池モジュール１の変換効率が２０％の場合である。　
　Ｂは、太陽電池セル４０での光吸収分を考慮に入れた太陽電池セル６０の変換効率である。 Next, the effect when the power generation unit 4 and the power generation unit 6 are electrically connected in parallel will be described.
First, a case where the power generation unit 4 and the power generation unit 6 are electrically connected in series will be described as a comparative example.
FIG. 9 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
A1 in FIG. 9 is a case where the conversion efficiency of the solar cell module 1 is 26%.
A2 is a case where the conversion efficiency of the solar cell module 1 is 24%.
A3 is a case where the conversion efficiency of the solar cell module 1 is 22%.
A4 is a case where the conversion efficiency of the solar cell module 1 is 20%.
B is the conversion efficiency of the solar battery cell 60 taking into account the amount of light absorption in the solar battery cell 40.

　図９は、シミュレーションにより求められた結果である。　
　この場合、発電部４の出力電圧と発電部６の出力電圧は等しいものとした。
　太陽電池セル６０は、ＣＩＧＳ系の太陽電池セルとした。光吸収層６１のバンドギャップは、１．１ｅＶとした。太陽電池セル６０の変換効率は、２０．０％とした。　
　なお、発電部４の出力電圧と発電部６の出力電圧が等しければ、光吸収層６１の材料が変わっても同様の結果が期待できる。 FIG. 9 shows the results obtained by simulation.
In this case, the output voltage of the power generation unit 4 and the output voltage of the power generation unit 6 are assumed to be equal.
The solar battery cell 60 was a CIGS solar battery cell. The band gap of the light absorption layer 61 was 1.1 eV. The conversion efficiency of the solar battery cell 60 was 20.0%.
If the output voltage of the power generation unit 4 is equal to the output voltage of the power generation unit 6, the same result can be expected even if the material of the light absorption layer 61 is changed.

　図９から分かるように、光吸収層４３のバンドギャップが１．２ｅＶ以上１．７ｅＶ以下の範囲では、光吸収層４３のバンドギャップが大きくなると太陽電池セル６０に入射する光の波長領域が広がる。そのため、図９中のＢから分かるように、光吸収層４３のバンドギャップが大きくなるに従い、太陽電池セル６０の変換効率が増加していく。その結果、図９中のＡ１～Ａ４から分かるように、２０％～２６％という高い変換効率を有する太陽電池モジュール１とするのに必要となる太陽電池セル４０の変換効率が減少していく。　
　また、光吸収層４３のバンドギャップが１．７ｅＶを超えた場合には、図９中のＢから分かるように、太陽電池セル６０の変換効率は減少していく。 As can be seen from FIG. 9, in the range where the band gap of the light absorption layer 43 is 1.2 eV or more and 1.7 eV or less, the wavelength region of light incident on the solar battery cell 60 is widened as the band gap of the light absorption layer 43 is increased. . Therefore, as can be seen from B in FIG. 9, the conversion efficiency of the solar battery cell 60 increases as the band gap of the light absorption layer 43 increases. As a result, as can be seen from A1 to A4 in FIG. 9, the conversion efficiency of the solar battery cell 40 required to make the solar battery module 1 having a high conversion efficiency of 20% to 26% decreases.
Moreover, when the band gap of the light absorption layer 43 exceeds 1.7 eV, as can be seen from B in FIG. 9, the conversion efficiency of the solar battery cell 60 decreases.

　ここで、光吸収層４３のバンドギャップが大きくなるほど、太陽電池セル６０に入射する光の波長領域が広がるので、太陽電池セル６０の変換効率は増加するとも考えられる。　
　しかしながら、発電部４と発電部６を電気的に直列接続した場合には、太陽電池セル４０に流れる電流の値と、太陽電池セル６０に流れる電流の値が同じになる。　
　また、光吸収層４３のバンドギャップが大きくなると、太陽電池セル４０に流れる電流の値が小さくなる。　
　そのため、光吸収層４３のバンドギャップが大きくなると、太陽電池セル６０に流れる電流の値が小さくなる。　
　その結果、光吸収層４３のバンドギャップが１．７ｅＶを超えた場合には、太陽電池セル６０の変換効率はかえって減少することになる。 Here, as the band gap of the light absorption layer 43 is increased, the wavelength region of light incident on the solar cell 60 is widened, so that the conversion efficiency of the solar cell 60 may be increased.
However, when the power generation unit 4 and the power generation unit 6 are electrically connected in series, the value of the current flowing through the solar battery cell 40 and the value of the current flowing through the solar battery cell 60 are the same.
Moreover, when the band gap of the light absorption layer 43 becomes large, the value of the electric current which flows into the photovoltaic cell 40 becomes small.
Therefore, when the band gap of the light absorption layer 43 increases, the value of the current flowing through the solar battery cell 60 decreases.
As a result, when the band gap of the light absorption layer 43 exceeds 1.7 eV, the conversion efficiency of the solar battery cell 60 is reduced.

　次に、発電部４と発電部６を電気的に並列接続した場合について説明する。　
　図１０は、太陽電池セル４０の変換効率と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。　
　なお、発電部４と発電部６を電気的に並列接続すること以外は、図９の場合と同じである。　
　図１０から分かるように、光吸収層４３のバンドギャップが１．２ｅＶ以上１．７ｅＶ以下の範囲では、図９の場合と同様の結果となる。　
　一方、光吸収層４３のバンドギャップが１．７ｅＶを超えた場合には、図１０中のＢから分かるように、太陽電池セル６０の変換効率はさらに増加する。　
　発電部４と発電部６を電気的に並列接続すれば、太陽電池セル４０に流れる電流の値が小さくなっても、太陽電池セル６０に流れる電流の値が同じように小さくなることはない。　
　そのため、光吸収層４３のバンドギャップが１．７ｅＶを超えた場合であっても、太陽電池セル６０の変換効率はさらに増加する。　
　その結果、図１０中のＡ１～Ａ４から分かるように、光吸収層４３のバンドギャップの広い範囲において、２０％～２６％という高い変換効率を有する太陽電池モジュール１とするのに必要となる太陽電池セル４０の変換効率が減少していく。　
　このことは、太陽電池モジュール１の設計に対する自由度が大きくなることをも意味する。 Next, the case where the power generation unit 4 and the power generation unit 6 are electrically connected in parallel will be described.
FIG. 10 is a graph for illustrating the relationship among the conversion efficiency of the solar battery cell 40, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1.
In addition, it is the same as that of the case of FIG. 9 except connecting the electric power generation part 4 and the electric power generation part 6 electrically in parallel.
As can be seen from FIG. 10, when the band gap of the light absorption layer 43 is in the range of 1.2 eV to 1.7 eV, the same result as in FIG. 9 is obtained.
On the other hand, when the band gap of the light absorption layer 43 exceeds 1.7 eV, as can be seen from B in FIG. 10, the conversion efficiency of the solar battery cell 60 further increases.
If the power generation unit 4 and the power generation unit 6 are electrically connected in parallel, even if the value of the current flowing through the solar battery cell 40 is reduced, the value of the current flowing through the solar battery cell 60 is not similarly reduced.
Therefore, even if the band gap of the light absorption layer 43 exceeds 1.7 eV, the conversion efficiency of the solar battery cell 60 further increases.
As a result, as can be seen from A1 to A4 in FIG. 10, the solar cell module 1 required to obtain a high conversion efficiency of 20% to 26% in a wide range of the band gap of the light absorption layer 43 is obtained. The conversion efficiency of the battery cell 40 decreases.
This also means that the degree of freedom for designing the solar cell module 1 is increased.

　図１１および図１２は、太陽電池セル４０の変換効率が理論値以下となる領域と、光吸収層４３のバンドギャップと、太陽電池モジュール１の変換効率との関係を例示するためのグラフ図である。　
　図１１は、発電部４と発電部６を電気的に直列接続した場合である。　
　図１２は、発電部４と発電部６を電気的に並列接続した場合である。　
　なお、図１１および図１２において、縦軸の「１」以下の領域が太陽電池セル４０の変換効率が理論値以下となる領域となる。　
　図１１と図１２を比較すると、図１２の場合（発電部４と発電部６を電気的に並列接続した場合）の方が、光吸収層４３のバンドギャップが大きくなっても、高い変換効率を有する太陽電池モジュール１を構成することができる。　
　すなわち、発電部４と発電部６を電気的に並列接続すれば、高い変換効率を有する太陽電池モジュール１とすることが容易となる。　
　このことは、太陽電池モジュール１の設計に対する自由度が大きくなることを意味する。 FIGS. 11 and 12 are graphs for illustrating the relationship between the conversion efficiency of the solar battery module 1, the region where the conversion efficiency of the solar battery cell 40 is less than the theoretical value, the band gap of the light absorption layer 43, and the conversion efficiency of the solar battery module 1. is there.
FIG. 11 shows a case where the power generation unit 4 and the power generation unit 6 are electrically connected in series.
FIG. 12 shows a case where the power generation unit 4 and the power generation unit 6 are electrically connected in parallel.
In FIG. 11 and FIG. 12, the region below “1” on the vertical axis is a region where the conversion efficiency of the solar battery cell 40 is less than or equal to the theoretical value.
11 and 12 are compared, the conversion efficiency in the case of FIG. 12 (when the power generation unit 4 and the power generation unit 6 are electrically connected in parallel) is higher even if the band gap of the light absorption layer 43 becomes larger. The solar cell module 1 having can be configured.
That is, if the power generation unit 4 and the power generation unit 6 are electrically connected in parallel, the solar cell module 1 having high conversion efficiency can be easily obtained.
This means that the degree of freedom for designing the solar cell module 1 is increased.

　ここで、発電部４の出力電圧は、太陽電池セル４０に設けられた光吸収層４３の数（溝４７の数）により設定することができる。　
　そのため、太陽電池セル４０を１つ設ければ、図９～図１２において説明した効果を得ることができる。　
　ところが、太陽電池セル４０においては、複数の光吸収層４３は電極４２および電極４５により電気的に直列接続されている。　
　そのため、太陽電池セル４０の数が１つの場合には、電極４２、電極４５、および光吸収層４３の一部が損傷すると、発電部４からの電力供給が停止するおそれがある。　
　本実施の形態に係る太陽電池モジュール１に設けられた発電部４においては、複数の太陽電池セル４０が電気的に並列接続されている。　
　そのため、一部の太陽電池セル４０が損傷したとしても、図９～図１２において説明した効果を得ることができる。　
　このことは、太陽電池モジュール１の一部に光Ｌが入射しない場合（例えば、日陰となった場合）も同様である。　
　すなわち、本実施の形態に係る太陽電池モジュール１とすれば、太陽電池モジュール１の信頼性を向上させることができる。 Here, the output voltage of the power generation unit 4 can be set by the number of light absorption layers 43 provided in the solar battery cell 40 (the number of grooves 47).
Therefore, if one solar battery cell 40 is provided, the effects described in FIGS. 9 to 12 can be obtained.
However, in the solar battery cell 40, the plurality of light absorption layers 43 are electrically connected in series by the electrode 42 and the electrode 45.
Therefore, in the case where the number of the solar battery cells 40 is one, if a part of the electrode 42, the electrode 45, and the light absorption layer 43 is damaged, the power supply from the power generation unit 4 may be stopped.
In the power generation unit 4 provided in the solar cell module 1 according to the present embodiment, a plurality of solar cells 40 are electrically connected in parallel.
Therefore, even if some of the solar cells 40 are damaged, the effects described in FIGS. 9 to 12 can be obtained.
The same applies to the case where the light L is not incident on a part of the solar cell module 1 (for example, when it is shaded).
That is, if it is set as the solar cell module 1 which concerns on this Embodiment, the reliability of the solar cell module 1 can be improved.

　以上、本発明のいくつかの実施形態を例示したが、これらの実施形態は、例として提示したものであり、発明の範囲を限定することは意図していない。これら新規な実施形態は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更などを行うことができる。これら実施形態やその変形例は、発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。また、前述の各実施形態は、相互に組み合わせて実施することができる。 As mentioned above, although some embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

Claims (7)

　電気的に並列接続された複数の第１太陽電池セルを有する第１発電部と、
　電気的に直列接続された複数の第２太陽電池セルを有し、前記第１発電部の光の入射側とは反対側に設けられ、前記第１発電部と電気的に並列接続された第２発電部と、
　を備え、
　前記第１太陽電池セルは、電気的に直列接続された複数の第１光吸収層を有する太陽電池モジュール。 A first power generation unit having a plurality of first solar cells electrically connected in parallel;
A plurality of second solar cells electrically connected in series, provided on a side opposite to the light incident side of the first power generation unit, and electrically connected in parallel with the first power generation unit; Two power generation units,
With
The first solar battery cell is a solar battery module having a plurality of first light absorption layers electrically connected in series. 　前記第２太陽電池セルは、前記第１光吸収層のバンドギャップよりも小さいバンドギャップを有する第２光吸収層を備えている請求項１記載の太陽電池モジュール。 The solar cell module according to claim 1, wherein the second solar battery cell includes a second light absorption layer having a band gap smaller than a band gap of the first light absorption layer. 　前記第１光吸収層のバンドギャップは、１．４ｅＶ以上、３．０ｅＶ以下である請求項１記載の太陽電池モジュール。 The solar cell module according to claim 1, wherein a band gap of the first light absorption layer is 1.4 eV or more and 3.0 eV or less. 　前記第２光吸収層のバンドギャップは、１．０ｅＶ以上、１．４ｅＶ以下である請求項２記載の太陽電池モジュール。 The solar cell module according to claim 2, wherein a band gap of the second light absorption layer is 1.0 eV or more and 1.4 eV or less. 　前記第１太陽電池セルは、Ｇａの含有量が多いＣＩＧＳ系の太陽電池セル、ＣＺＴＳ系の太陽電池セル、有機薄膜系の太陽電池セル、およびペロブスカイト系の太陽電池セルのいずれかである請求項１記載の太陽電池モジュール。 The first solar cell is any one of a CIGS solar cell, a CZTS solar cell, an organic thin film solar cell, and a perovskite solar cell with a high Ga content. 1. The solar cell module according to 1. 　前記第２太陽電池セルは、結晶シリコン太陽電池セル、Ｉｎの含有量が多いＣＩＧＳ系の太陽電池セル、ＣＩＴ系の太陽電池セル、およびＣｄＴｅ系の太陽電池セルのいずれかである請求項１記載の太陽電池モジュール。 2. The second solar cell is any one of a crystalline silicon solar cell, a CIGS solar cell having a high In content, a CIT solar cell, and a CdTe solar cell. Solar cell module. 　前記第１発電部の光の入射側に設けられ、アルカリ金属を含むガラスから形成された保護部をさらに備え、
　前記第１太陽電池セル、および前記第２太陽電池セルの少なくともいずれかは、ＣＩＧＳ系の太陽電池セルである請求項１記載の太陽電池モジュール。
　 Provided with a light incident side of the first power generation unit, further comprising a protection unit formed of glass containing an alkali metal;
The solar cell module according to claim 1, wherein at least one of the first solar cell and the second solar cell is a CIGS solar cell.
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WO2024071284A1 (en) * 2022-09-28 2024-04-04 株式会社カネカ Solar cell module production method and solar cell module
WO2024204139A1 (en) * 2023-03-29 2024-10-03 株式会社カネカ Solar cell module

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