JP2016122755A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which a solar cell module using a multiple junction cell has loss for each multiple joint cell, which reduces power generation efficiency.SOLUTION: The solar cell module with high power generation efficiency can be provided by including: a first solar cell group to which a plurality of first solar cells are connected; and a second solar cell group, disposed on a surface opposite to a light-receiving surface of the first solar cell group through an insulating material, to which a plurality of second solar cells whose absorption wavelength is located on a longer wavelength side than the first solar cells.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solar cell module.

  In recent years, the use of renewable energy has been desired from the viewpoint of depletion of fossil fuel resources and the suppression of global warming gas emissions. There are a wide variety of renewable energy sources such as sunlight, hydropower, wind power, geothermal power, tidal power, and biomass. Among them, sunlight has a large amount of available energy, and there are geographical restrictions on other renewable energy sources. Because of the relatively small amount, early development and popularization of technology that can efficiently use energy from sunlight is desired.

  As a solar cell that efficiently photoelectrically converts sunlight, a tandem solar cell (stacked solar cell) in which a plurality of solar cells having different band gaps (forbidden band widths) are stacked is known. This tandem solar cell is high because a plurality of solar cells each photoelectrically convert light in a wavelength range corresponding to the band gap and efficiently convert light (for example, sunlight) showing a continuous spectrum. It is expected as a solar cell showing conversion efficiency.

  For example, a solar cell using a crystalline silicon substrate transmits infrared light of 1150 nm or more, which is the long wavelength end of the absorption wavelength of silicon. Therefore, a tandem solar cell is known in which germanium solar cells that generate power by absorbing infrared rays are arranged on the back surface opposite to the light receiving surface of a silicon crystal solar cell, and these are connected in series.

In this case, since the near infrared ray transmitted through the 180 μm Si single crystal substrate is about ¼ of the energy of the whole sunlight, a so-called tandem structure in which silicon solar cells and germanium solar cells are connected in series is used. The solar cell J _SC (short-circuit current density) depends on the near-infrared energy transmitted through the silicon substrate. Therefore, the solar cell J _{SC is} about 1/4 of the solar cell using only the silicon substrate, and current matching is insufficient. There was little power generation efficiency.

  Therefore, as shown in Patent Document 1, a silicon solar cell having two germanium solar cells connected in series is arranged on the back surface of the silicon solar cell, and the silicon solar cell and two germanium solar cells are connected in series. There are known multi-junction cells in which are connected in parallel.

JP 2013-239476 A

However, in general, the cell V _oc (open circuit voltage) of a silicon solar cell is not exactly twice that of the germanium solar cell V _oc , so that the V of the silicon solar cell and two germanium solar cells connected in series _oc does not match. Therefore, a solar cell module using a multi-junction cell in which a silicon solar cell and two germanium solar cells connected in series are connected in parallel may have a loss for each multi-junction cell and may reduce power generation efficiency. . This invention is made | formed in view of the above-mentioned subject, and aims at obtaining a solar cell module with high electric power generation efficiency.

  The solar cell module of the present invention is installed via an insulating material on the first solar cell group in which a plurality of first solar cells are connected and on the surface side opposite to the light receiving surface of the first solar cell group. A second solar cell group in which a plurality of second solar cells having an absorption wavelength longer than that of the first solar cells are connected is provided.

  In the solar cell module of the present invention, the plurality of first solar cells constituting the first solar cell group are connected in series and the plurality of second solar cells constituting the second solar cell group. The solar cells are connected in series, and the first solar cell group and the second solar cell group are connected in parallel.

  In the solar cell module of the present invention, the open voltage of the first solar cell group and the open voltage of the second solar cell group are substantially equal.

  In the solar cell module of the present invention, the first solar cell group is composed of a silicon solar cell, and the second solar cell group is composed of a germanium solar cell.

  In the solar cell module of the present invention, the second solar cell group uses quantum dots.

  According to the present invention, a solar cell module with high power generation efficiency can be provided.

It is typical sectional drawing which shows the solar cell module of this invention. It is typical sectional drawing which shows the solar cell module of this invention. It is a schematic diagram which shows the quantum dot perovskite solar cell used for the solar cell module of this invention. It is a schematic diagram which shows the quantum dot solar cell used for the solar cell module of this invention. It is a schematic diagram which shows the perovskite solar cell used for the solar cell module of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a solar cell module of the present invention. On the light receiving surface side of a transparent insulating sheet 15 such as EVA (ethylene-vinyl acetate) resin or olefin resin, first solar cells 11 made of silicon single crystal cells are mounted vertically and horizontally, respectively, and interconnectors 12 are connected in series to form a first solar cell group 23. The interconnector 12 is a solder-plated linear ribbon, one of which is electrically connected to the light receiving surface side electrode of the first solar battery cell 11 and the other is connected to the back surface side electrode. The first solar battery cell 11 is sealed with a transparent EVA resin 14. Further, a cover glass 13 is disposed on the EVA resin 14 to form a light incident surface. As a 1st photovoltaic cell, what is necessary is just a photovoltaic cell which permeate | transmits infrared rays, such as a silicon polycrystal cell other than a silicon single crystal cell.

  Below the light receiving surface side of the insulating sheet 15, second solar cells 19 made of germanium crystal cells are arranged vertically and horizontally on the EVA resin 17, and are connected in series by interconnectors 20 respectively. The solar cell group 24 is configured. The second solar cell group 24 can generate power by absorbing light having a longer wavelength than that of the first solar cell so that the second solar cell group 24 can generate power using long-wavelength light such as infrared rays transmitted through the first solar cell group 23. It has become.

  The interconnector 20 is a solder-plated linear ribbon, one of which is electrically connected to the light receiving surface side electrode of the second solar battery cell and the other is connected to the back surface side electrode. The second solar battery cell is sealed with EVA resin 16. A back sheet 18 is disposed below the EVA resin 17 to protect the back surface of the solar cell module 10.

  A second solar cell group 24 consisting of second solar cells 19 connected in series with a first solar cell group 23 consisting of first solar cells 11 connected in series is connected in parallel, Electric power can be taken out by the positive terminal 21 and the negative terminal 22.

The open circuit voltage V _oc per silicon single crystal cell, which is the first solar battery cell, is 0.65 V, and 48 solar battery modules are connected in series to one solar battery module 23. V _oc of the first solar cell group 23 is 31.2V.

On the other hand, the open circuit voltage V _oc of one germanium single crystal cell, which is the second solar battery cell, is 0.27 V, and 116 pieces are connected in series to one solar battery module. Therefore, in one solar cell module, V _oc of the second solar cell group is 31.3 V, which is substantially equal to V _{oc of} the first solar cell group.

By making V _{oc of} the first solar cell group 23 substantially equal to V _oc of the second solar cell group 24 ′, the power generation efficiency of the solar cell module can be increased.

  Since the first solar cell group 23 and the second solar cell group 24 are insulated by the insulating sheet 15, there is no fear that the current leaks, and the first solar cell group 23 and the second solar cell group 24 Since both ends of the battery group 24 are connected in parallel, wiring is simple and productivity is high.

The number of first solar cells connected in series and the number of second solar cells connected in series may be determined so that their open circuit voltages V _oc substantially match.
0.95 ≦ _{(V oc} of the first solar cell group) / _{(V oc} of the second solar cell group) ≦ 1.05
It is preferable that

  Light incident from the light receiving surface side of the solar cell module 10 is absorbed by the first solar cell to generate power. In addition, light leaked from the gap between the first solar cell groups 23 and long-wavelength light such as infrared rays that are not absorbed by the first solar cell 11 enter the second solar cell group 24 to generate power. An efficient solar cell module can be obtained.

(Embodiment 2)
FIG. 2 is a schematic cross-sectional view showing the solar cell module of the present invention. A first solar cell 11 made of a silicon single crystal cell is placed vertically and horizontally on a transparent insulating sheet 15 such as EVA resin or olefin resin, and connected in series by an interconnector 12, respectively. A solar cell group 23 is configured. The interconnector 12 is a solder-plated linear ribbon, one of which is electrically connected to the light receiving surface side electrode of the first solar battery cell 11 and the other is connected to the back surface side electrode. The first solar battery cell 11 is sealed with a transparent EVA resin 14. Further, a cover glass 13 is disposed on the EVA resin 14 to form a light incident surface. As a 1st photovoltaic cell, what is necessary is just a photovoltaic cell which permeate | transmits infrared rays, such as a silicon polycrystal cell other than a silicon single crystal cell.

  A glass substrate 25 is provided on the lower side opposite to the light receiving surface side of the insulating sheet 15, and a second solar cell group 24 ′ composed of second solar cells 29 is formed on the glass substrate 25. The second solar battery cell 29 is a thin film germanium solar battery, and is formed by sequentially laminating a transparent conductive layer 26, a thin film germanium power generation layer 27, and a back electrode layer 28 on a glass substrate 25. Each layer is patterned and divided into a large number of solar cells 29. By electrically connecting to the adjacent power generation layer 27 via the transparent conductive layer 26 and the back electrode layer 28, the respective solar cells 29 are connected in series to form a second solar cell group 24 ′. ing. Further, the second solar cell group 24 ′ is sealed with the EVA resin 30. A back sheet 31 is disposed on the back surface of the solar cell module 10 '.

  A second solar cell group 24 ′ consisting of a second solar cell 29 connected in series with a first solar cell group 23 consisting of a first solar cell 11 connected in series is connected in parallel. The positive electrode terminal 21 and the negative electrode terminal 22 can extract electric power.

The open voltage V _oc of one silicon single crystal cell as the first solar battery cell 11 is 0.65V, and the V _oc of the first solar battery group 23 connected in series in 48 is 31.2V. is there.

On the other hand, the open circuit voltage V _{oc of} one thin-film germanium cell as the second solar battery cell 29 is 0.35V, and the second solar battery group 24′V _oc connected in series is 31.2V. And V _{oc of} the second solar cell group is substantially equal.

First and V _oc of the solar cell group 23 connected in series, by substantially equal V _oc of the second solar cell group 24 'connected in series, it is possible to enhance the power generation efficiency of the solar cell module.

(Embodiment 3)
In the solar battery cell 29 of the above-described second embodiment, instead of a thin film germanium solar battery, InN having a diameter of 3 nm to 50 nm as a quantum dot is formed on a perovskite formed by mixing CH3NH3I and PbCl2 at a molar ratio of 3: 1. A quantum dot perovskite solar cell using a thin film in which nanoparticles are dispersed discretely can be used. By using InN nanoparticles with high absorbance in the near infrared as quantum dots, a second solar cell group can be configured using quantum dot perovskite solar cells. InN nanoparticles can be formed, for example, by the method described in JP2012-246470A.

  FIG. 3 is a schematic view of a perovskite solar cell used in the solar cell module of the present invention. The quantum dot perovskite solar cell 40 has a structure in which a transparent electrode 42, a hole transport layer 43, a perovskite layer 44, an electron transport layer 46, and a metal electrode 47 are sequentially laminated on a glass substrate 41. InN nanoparticles 45 are dispersed in the perovskite layer 44. The interval between the InN nanoparticles 45 is about 2 nm. By arranging the InN nanoparticles at intervals of about 2 nm, the InN nanoparticles are tunnel-coupled to each other, and it is possible to form a narrow band gap perovskite layer 44 with high absorbance. The hole transport layer 43, the perovskite layer 44 and the electron transport layer 46 constitute a power generation layer 48.

  A solar cell module using a perovskite solar cell can have the same structure as the solar cell module shown in FIG. That is, the power generation layer 27 in FIG. 2 is replaced with the power generation layer 48 of the perovskite solar cell.

  Perovskite solar cells can be made as follows. First, ITO having a thickness of 100 nm is formed on the glass substrate 41 by sputtering, and the transparent electrode 42 is formed.

  Next, on the transparent electrode 42, PEDOT: PSS (Poly (3,4-ethylene dioxythiophene) Polystyrene sulfate) is applied by spin coating to 50 nm to form the hole transport layer 43.

  Next, a solution obtained by adding 50 wt% of InN nanoparticles having a diameter of 10 nm or more with a de Broglie wavelength that does not generate a quantum size effect to the perovskite solution on the hole transport layer 43 by spin coating. By applying about 1 μm in thickness, a perovskite layer 44 in which InN nanoparticles 45 are dispersed is formed.

  Next, on the perovskite layer 44, PCBM ([6,6] -Phenyl-C61-Butylic Acid Methyl Ester) is spin-coated to form the electron transport layer 46. The thickness of the electron transport layer 46 is about 100 nm. After stacking the electron transport layer 46, firing is performed at about 100 ° C. Finally, a quantum dot perovskite solar cell 40 is formed by forming an aluminum electrode having a thickness of 100 nm by vacuum deposition.

  Titanium oxide fine particles may be used as the electron transport layer 46. In this case, 2 μm of titanium oxide fine particles are applied on ITO, and a perovskite layer, a PEDOT: PSS layer, and an aluminum electrode are sequentially formed on the titanium oxide particles.

  In this way, a near-infrared solar cell can be formed. Since the power generation layer 48 can be formed by a non-vacuum process such as spin coating or screen printing, productivity can be improved.

(Embodiment 4)
FIG. 4 is a schematic diagram of a quantum dot solar cell used in the solar cell module of the present invention. The InN nanoparticles 45 ′ are core-shell type nanoparticles and are dispersed in an insulating material of acrylic resin 44 ′. The core-shell type InN nanoparticles 45 ′ are particles obtained by coating InN particles 45a ′ having a diameter of 10 nm with GaN 45b ′ having a thickness of about 1 nm.

  When the InN nanoparticles are core-shell type, the power generation characteristics are improved. In addition, since the InN nanoparticles 45 ′ are in contact with each other to form a tunnel junction, it is not necessary to disperse InN nanoparticles discretely. Further, the acrylic resin 44 ′ in which the InN nanoparticles 45 ′ are dispersed is not always necessary, and the InN nanoparticles 45 ′ may be sintered.

  When core-shell type nanoparticles are in contact with each other, the distance “a” in which the core radius is doubled and the distance “b” in which the shell thickness is doubled are regarded as periodic potentials, and a Bloch function is created. The allowed energy band obtained from the Bloch function solution is the intermediate band. Electrons can move through the intermediate band.

  By sandwiching the power generation layer 48 ′ containing InN nanoparticles 45 ′ between the hole transport layer 43 and the electron transport layer 46, sunlight can be extracted as electric energy.

  The solar cell module using the quantum dot solar cell can have the same structure as the solar cell module shown in FIG. That is, the power generation layer 27 in FIG. 2 is replaced with the power generation layer 48 ′ of the quantum dot solar cell.

  The first solar battery cell 11 shown in the above-described first or second embodiment shown in the third or fourth embodiment is a silicon solar battery, but absorbs visible light instead of the silicon solar battery. A thin film solar cell using a perovskite that generates electric power can be used.

(Embodiment 5)
The first solar battery cell 11 shown in the first or second embodiment described above is a silicon solar battery, but instead of a silicon solar battery, a thin film solar battery using a perovskite having an absorption region in the wavelength of visible light is used. A perovskite solar cell that can be used uses a perovskite as an intrinsic semiconductor between a transport layer and an electron transport layer, and sandwiches the hole transport layer and the electron transport layer. As the hole transport layer, PEDOT: PSS An organic material such as PCBM can be used for the electron transport layer. The hole transport layer and the electron transport layer are each connected to an electrode.

  Furthermore, by forming an n-type perovskite layer and a p-type perovskite layer, an inexpensive solar cell that does not require the above-described PEDOT: PSS hole transport layer or PCBM electron transport layer can be provided.

  FIG. 5 is a schematic diagram showing a perovskite solar cell used in the solar cell module of the present invention. A transparent conductive layer 52 having a thickness of 100 nm is formed on the glass substrate 51 by sputtering. Next, a 200 nm p-type perovskite layer 53 and a 200 nm n-type perovskite layer 54 are sequentially formed. Finally, a perovskite solar cell 50 can be formed by forming an aluminum electrode 55 having a thickness of 100 nm by vacuum deposition.

Similar to the second solar battery group, the perovskite solar battery constituting the first solar battery group is divided into a large number of solar battery cells, and the respective solar battery cells are connected in series. Also, the V _oc of the first solar cell group composed of perovskite solar cells, V _oc of the second solar cell units arranged on the side opposite to the light receiving surface of the perovskite solar cells in series so as substantially equal The number of connected cells has been adjusted.

As a perovskite material, CH ₃ NH ₃ I and PbCl ₂ are dissolved in a solvent at a molar ratio of 3: 1, and further added with 1 wt% InCl ₃ to form a p-type perovskite layer 53 by spin coating. can do. As an additive, a compound of B, Al, Ga, Ti may be used instead of In. The p-type perovskite layer can also be used as a hole transport layer of a general perovskite solar cell.

As a perovskite material, CH ₃ NH ₃ I and PbCl ₂ are dissolved in a solvent at a molar ratio of 3: 1, and 1 wt% of PCl ₅ is added to form a n-type perovskite layer 54 by spin coating. can do. As additives, N, P, As, Sb, and Bi compounds may be used. The n-type perovskite layer can also be used as an electron transport layer of a general perovskite solar cell.

  A solar cell having a power generation layer using a p-type perovskite in which a trivalent impurity is added to a perovskite and an n-type perovskite in which a pentavalent impurity is added to a perovskite. Can be improved.

  Moreover, productivity can be improved by comprising a 1st solar cell group with the perovskite solar cell which consists of a general hole transport layer, a perovskite layer, and an electron carrying layer.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 10 ... Solar cell module 11 ... Solar cell 12 ... Interconnector 13 ... Cover glass 14 ... EVA resin 15 ... Insulating sheet 16 ... EVA resin 17 ... EVA resin 18 ... Back sheet 19 ... Solar cell 20 ... Interconnector 21 ... Positive electrode Terminal
22 ... Negative electrode terminal 23 ... First solar cell group 24 ... Second solar cell group 25 ... Glass substrate 26 ... Transparent conductive layer 27 ... Power generation layer 28 ... Back electrode layer 29 ... Solar cell 30 ... EVA resin 31 ... Back Sheet 40 ... Quantum dot perovskite solar cell 41 ... Glass substrate 42 ... Transparent electrode 43 ... Hole transport layer 44 ... Perovskite layer 44 '... Acrylic resin 45, 45' ... InN nanoparticles 46 ... Electron transport layer 47 ... Metal electrodes 48,48 '... Power generation layer 50 ... Perovskite solar cell 51 ... Glass substrate 52 ... Transparent conductive layer 53 ... P-type perovskite layer 54 ... N-type perovskite layer 55 ... Aluminum electrode

Claims (5)

A first solar cell group in which a plurality of first solar cells are connected;
A plurality of second solar cells that are installed on the surface side opposite to the light receiving surface of the first solar cell group via an insulating material and have an absorption wavelength longer than the first solar cell. A solar cell module provided with a second solar cell group connected in a sheet. While the plurality of first solar cells constituting the first solar cell group are connected in series,
A plurality of the second solar cells constituting the second solar cell group are connected in series,
The first solar cell group and the second solar cell group are solar cell modules connected in parallel.   The solar cell module according to claim 1 or 2, wherein an open circuit voltage of the first solar cell group and an open circuit voltage of the second solar cell group are substantially equal.   4. The solar cell module according to claim 1, wherein the first solar cell group is made of a silicon solar cell, and the second solar cell group is made of a germanium solar cell. The solar cell module according to any one of claims 1 to 3, wherein the second solar cell group includes solar cells using quantum dots.

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