JP7094668B2 - Solar cell module and photovoltaic system - Google Patents

Description

The embodiment relates to a solar cell module and a photovoltaic power generation system.

As a highly efficient solar cell, there is a multi-junction type (tandem) solar cell. Since an efficient cell can be used for each wavelength band, higher efficiency is expected than that of a single junction. Chalcopyrite solar cells such as CIGS are known to have high efficiency, and can be a top cell candidate by widening the gap. However, in a module in which solar cells having different band gaps are joined, the connection method has not been sufficiently studied.

Japanese Unexamined Patent Publication No. 2013-33832.

The embodiment provides a solar cell module and a photovoltaic power generation system with improved conversion efficiency.

In the solar cell module of the embodiment, a first solar cell panel having a plurality of first submodules including a plurality of first solar cell cells and a first solar cell panel are laminated to form a plurality of second solar cell cells. It has a second solar cell panel having a plurality of second submodules including , the first solar cell panel exists on the light incident side, and the first solar cell panel and the second solar cell panel are electrically parallel to each other. The plurality of first solar cells connected and included in the plurality of first submodules are electrically connected in series, and the plurality of first submodules are electrically connected in parallel. The plurality of second solar cells included in the plurality of second submodules are electrically connected in series. A plurality of second submodules are electrically connected in series.

A perspective conceptual diagram of a solar cell module according to an embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. A perspective conceptual diagram of a solar cell module according to an embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. Sectional conceptual diagram of the solar cell module which concerns on embodiment. A perspective conceptual diagram of a solar cell module according to an embodiment. Sectional conceptual diagram of the solar cell module which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. The schematic diagram of the solar cell panel which concerns on embodiment. A conceptual diagram of a solar cell system according to an embodiment.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Some of the symbols in the figure are omitted.
(First Embodiment)
The solar cell module of the first embodiment has a structure in which two or more solar cell panels are laminated. Two or more solar panels are electrically connected in parallel. As shown in the perspective conceptual diagram of FIG. 1, the solar cell module 100 according to the present embodiment has a first solar cell panel 10 and a second solar cell panel 20. The first solar cell panel 10 and the second solar cell panel 20 are laminated in the third direction. The first solar cell panel 10 and the second solar cell panel 20 are electrically connected in parallel. The depth direction of the solar cell module 100 is the first direction, and the width direction of the solar cell module 100 is the second direction. The first direction and the second direction intersect or are orthogonal to each other, and the surface including the first direction and the second direction is parallel to the panel surface of the solar cell module 100. The third direction is orthogonal to the first direction and orthogonal to the second direction. In the embodiment, two solar cell panels are laminated, but a solar cell module in which three or more solar cell panels are laminated may be used.

(1st solar cell panel)
The first solar cell panel 10 is a panel existing on the top side of the solar cell module 100, that is, on the light incident side. The first solar cell panel 10 has a plurality of solar cells having a light absorption layer having a wide band gap. Examples of the light absorption layer having a wide bandgap include any one or more of a compound semiconductor, a perovskite type compound, an oxide transparent semiconductor, and amorphous silicon. The first solar cell panel 10 of the embodiment is excellent in conversion efficiency even by itself. Therefore, it is also preferable that the first solar cell panel 10 of the embodiment is used as a single solar cell without being laminated with another solar cell panel. The first solar cell panel 10 has a plurality of first submodules including a plurality of first solar cell cells.

(2nd solar cell panel)
The second solar cell panel 20 is a panel existing on the bottom side of the solar cell module 100, that is, on the side opposite to the light incident side. The second solar cell panel 20 has a plurality of solar cells that generate electricity with transmitted light that has passed through the first solar cell panel 10. The second solar cell panel 20 has a plurality of second submodules including a plurality of second solar cell cells.

The second solar cell of the second solar cell panel 20 has a polycrystalline Si, a single crystal Si, or a perovskite type compound in the light absorption layer. The bandgap of the light absorption layer of polycrystalline Si, single crystal Si, or perovskite type compound is narrower than that of the light absorption layer of the first solar cell.

The second solar cell panel 20 includes a PERC (Passivated Emitter and Rear Contact cell) type, a PERL type (Passivated Emitter and Rear Locally diffusion cell), a PERT type (Passivated Emitter and Rear Totally diffusion cell), and a back contact type (Interdigitated Back). Contact cells) and panels using heterojunction (HIT) solar cells can be mentioned.

The electric power generated by the first solar cell panel 10 and the second solar cell panel 20 is converted and stored, transmitted, or consumed. Both the electric power generated by the first solar cell panel 10 and the electric power generated by the second solar cell panel 20 need to be converted by a power converter (converter) in order to store, transmit, and consume the electric power. If the first solar cell panel 10 and the second solar cell panel 20 are converted by different converters, two converters are required. The power generation cost increases due to the increase in the number of converters. Therefore, the solar cell module 100 has only one power output terminal because the panels are electrically connected in parallel even if the number of stacked panels is two or more. Even if the conversion efficiency is improved, if the power generation cost is high, even if the conversion efficiency is improved by increasing the number of junctions, it is not preferable from the viewpoint of recovery of investment funds.

As shown in the schematic diagram of FIG. 2, the second solar cell panel 20 has a plurality of second submodules 21A including the second solar cell 21. The second solar cell 21 included in the second submodule 21A is arranged in the first direction and electrically connected in series. The second solar cell 21 included in the second submodule 21A is electrically connected in series. A plurality of second submodules 21A exist in a plurality of rows in the second direction and are arranged side by side. The plurality of second submodules 21A are electrically connected in series. One of the second submodules 21A is surrounded by a broken line. In the second solar cell panel 20, a plurality of second submodules 21A in which polygonal second solar cells 21 such as a square are electrically connected in series in the first direction are arranged in a plurality of rows in the second direction, and all the second solar cells are second. Generally, the solar cells 21 are electrically connected in series. The shape of the second solar cell 21 may be a polygonal straight line portion or a curved shape at the apex portion. The thin wire connecting the second solar cell 21 is an electric wiring connecting the second solar cell 21 in series. The first solar cell panel 10 is superposed on the second solar cell panel 20, the output voltages of the first solar cell panel 10 and the second solar cell panel 20 are made uniform, and the first solar cell panel 10 and the second solar cell are aligned. A structure that increases the total power generation amount of the panel 20 is required. When multiple solar panels are electrically connected in parallel, the output voltage due to the parallel connection is the lowest voltage. Therefore, it is preferable that the output voltage difference between the solar cells connected in parallel electrically is as small as possible.

The schematic diagram of FIG. 3 shows a schematic diagram of the first solar cell panel 10. The first solar cell panel 10 has a first submodule 11A including a first solar cell 11. One of the first submodules 11A is surrounded by a broken line. FIG. 4 shows a schematic diagram showing the first solar cell panel 10 shown in the schematic diagram of FIG. 3 in a circuit manner. The plurality of first solar cell 11s of the first solar cell panel 10 have a structure in which the first direction is the longitudinal direction, unlike the second solar cell 21 of the second solar cell panel 20. In the schematic views of FIGS. 3 and 4, the thin wire connecting the first solar cell 11 is an electric wiring connecting the first solar cell 21 in series. Further, in the schematic views of FIGS. 3 and 4, the thick line connecting the first solar cell 11 is an electric wiring connecting the first solar cell 21 in parallel. In FIGS. 3 and 4, four first submodules 11A in which four first solar cells 11 are connected in series are connected in parallel. In the schematic views of FIGS. 3 and 4, the first solar cell 11 is arranged so that the electrical polarities of the first submodule 11A are staggered, but the first solar cell 11 is arranged so that the electrical polarities of the first submodule 11A are aligned. The solar cell 11 may be arranged, and wiring for parallel connection may be further provided.

In the first solar cell 11 of the first solar cell panel, both the upper electrode and the lower electrode need to be transparent electrodes. The transparent electrode has a higher resistance than the metal electrode. When all the first solar cell 11s are connected in series in the second direction, the area per cell becomes large, and the conversion efficiency of the first solar cell panel 10 decreases due to the increase in the resistance of the transparent electrode. If the width of the solar cell 11 in the second direction is adjusted in consideration of the resistance of the transparent electrode and all of them are connected in series, the output voltage with the second solar cell panel 20 will not match. Further, for example, if the first solar cell panel 10 is composed of one solar cell, the output voltage difference from the second solar cell panel 10 will be significantly different.

Therefore, a plurality of first submodules 11A in which the first solar cell 11 of the first solar cell panel is electrically connected in series in the second direction are configured, and the plurality of first submodules 11A are electrically connected in the second direction. A structure in which they are connected in parallel with each other is preferable. When such a configuration is adopted, the output voltages of the first solar cell panel 10 and the second solar cell panel 20 can be matched while the first solar cell panel 10 has a connection form of the solar cell 11 having high conversion efficiency. .. The difference between the output voltages of the first solar cell panel 10 and the second solar cell panel 20 is preferably 2.0 V or less. The smaller the difference in output voltage, the smaller the loss due to the difference in output voltage, which is preferable. Therefore, the difference between the output voltages of the first solar cell panel 10 and the second solar cell panel 20 is more preferably 1.5 V or less, 1.0 V or less, and even more preferably 0.5 V or less. In the first solar cell panel 10, the number of parallel first submodules 11A is preferably 2 or more and 10 or less. If the number of parallel cells is small, the area of the transparent electrode per one solar cell 11 is large, and the power generation efficiency is lowered due to the increase in resistance caused by the transparent electrode. Further, if the number of parallel cells is too large, the number of solar cell 11s in the panel increases, the non-power generation area such as wiring increases, and the power generation efficiency decreases.

Here, the first solar cell panel 10 using CGSS (Cu _0.95 GaSe _1.95 S _0.05 ) having a Voc (opening voltage) of 0.95 V in the light absorption layer, and Voc in the light absorption layer. An example will be described of a solar cell module 100 in which a second solar cell panel 20 using polycrystalline Si of 0.66 is laminated.

The second solar cell 21 using Si for the light absorption layer has a second submodule 21A in which 10 cells are electrically connected in series in one row, and the second submodule 21A is arranged in six rows. All panels are electrically connected in series. The Voc of the second solar cell 21 is 0.66V. Since 60 cells of 0.66V are connected in series, the Voc of the second solar cell panel 20 is 39.6V (single value, Voc after mounting the panel is reduced to 37.8V). On the other hand, the Voc of the first solar cell 11 using CGSS for the light absorption layer is 0.95. In order to match Voc 39.6V of the second solar cell panel, it is preferable to connect the first solar cell 11 in 41 rows in series. When 0.15V is connected in 41 series, the Voc of the first solar cell 11 becomes 39.9V. Such a panel has a size of about 1 m in both the first direction and the second direction. For example, when the panel is divided into 41 in the second direction, the area of the first solar cell 11 is very large. Therefore, 41 series structures are arranged in parallel. The number of parallels is 2 or more and 10 or less. Generally, it is better to set so that the difference in Voc at the maximum output becomes small in consideration of Voc, FF, etc. of the bottom panel when the top panel is mounted.

(Second Embodiment)
The solar cell module of the second embodiment has a structure in which two or more solar cell panels are laminated. Two or more solar panels are electrically connected in parallel. As shown in the perspective conceptual diagram of FIG. 5, the solar cell module 101 according to the present embodiment has a first solar cell panel 10 and a second solar cell panel 20. The first solar cell panel 10 and the second solar cell panel 20 are laminated in the third direction. The first solar cell panel 10 and the second solar cell panel 20 are electrically connected in parallel. The first solar cell panel 10 has a bus bar 12 for connecting the first solar cell cells in the first solar cell panel 10 in parallel. The solar cell module 100 of the first embodiment and the solar cell module 101 of the second embodiment are common except that the bus bar 12 is provided. The description common to the first embodiment and the second embodiment will be omitted.

(Busbar)
The bus bar 12 is a metal plate for connecting a plurality of first submodules 11A in parallel in the second direction. The schematic diagram of FIG. 6 shows a schematic diagram of the first solar cell panel 10 of the second embodiment. The bus bar 12 is a metal wiring extending in the first direction. The bus bars 12 are arranged side by side in the second direction of the first solar cell panel 10. The bus bar 12 is arranged between both ends of the first solar cell panel 10 and the plurality of first submodules 11A. The metal used for the bus bar 12 is not particularly limited. For example, the bus bar 12 is preferably a wiring containing one or more metals of any one of Al, Cu, Au, Ag, Mo and W and the like. The width of the bus bar 12 is preferably 1 mm or more and 6 mm or less. If the bus bar 12 is too thin, the resistance becomes high and it becomes difficult to recover the current well, which is not preferable. Further, the portion where the bus bar 12 is provided is a non-power generation area. Therefore, if the wiring of the bus bar 12 is too thick, the amount of power generation will decrease, which is not preferable. The height of the bus bar 12 is not particularly limited, but is preferably 2 mm or less or 1 mm or less because wiring is difficult if the height is too high. Analysis of the solar cell module, such as the height of the bus bar 12, can be performed by top surface observation and cross-section observation. Perform elemental analysis as needed.

FIG. 7 shows a schematic cross-sectional view of the solar cell module 100. In the schematic diagram of FIG. 7, there are a first solar cell panel 10 having a first solar cell 11 and a second solar cell panel 20 having a second solar cell 21. The first solar cell panel 10 shown in the schematic diagram of FIG. 7 includes a bus bar 12, a substrate 13, a first electrode 14, a light absorption layer 15, a buffer layer 16, and a plurality of first solar cell cells 11 including a second electrode 17. including. In FIG. 7, the bus bar 12 is in contact with the first electrode 14, but may be in contact with the second electrode 17. P1, P2, and P3 represent the side surfaces of the cut by the patterns 1, 2, and 3. Although FIG. 7 illustrates a substrate configuration of a substrate type, the first solar cell panel 10 may adopt a substrate configuration of a super straight type. When the super straight type substrate configuration is adopted, the substrate 13 can bear the tempered glass on the light receiving surface side, which leads to the weight reduction of the solar cell panel 100. If it is a substrate type substrate configuration, it may be coated with a resin and inverted if necessary after production, and laminated with the second solar cell panel 20.

FIG. 7 shows a schematic diagram of six patterns (A), (B), (C), (D), (E) and (F). FIG. 7A shows a form in which the bus bar 12 is provided on the first electrode 14, and the first electrode 14 exists between the bus bar 13 and the substrate 13.

FIG. 7B shows a form in which the bus bar 13 is provided on the second electrode 17, and the second electrode 17 exists between the bus bar 12 and the light absorption layer 15.

FIG. 7C shows a form in which the bus bar 12 is provided on the substrate 13, and the bus bar 12 exists between the substrate 13 and the first electrode 14. The cut side surfaces of P4 are present at both ends of the bus bar 12 in the schematic diagram of FIG. 7 (C). If the bus bar 12 and the second electrode 17 may be wired in parallel, it is not necessary to form a cut section of P4. Even in the form shown in the schematic views of FIGS. 7A, 7B and 7C, the first solar cell 11 is arranged symmetrically so that the polarities of the first submodule 11A are staggered around the bus bar 12. Has been done.

FIG. 7D shows a form in which one bus bar 12 is provided on the first electrode 14 on the left side of the figure and one on the second electrode 17 on the right side of the figure. The two bus bars 12 overlap at least partially in the third direction. The polarity of the bus bar 12 on the first electrode 14 and the polarity of the bus bar 12 on the second electrode 17 are different. The insulating film 18 is made of resin, SiO ₂ , or the like, and insulates the two bus bars 12.

FIG. 7E shows a form in which one bus bar 12 is provided on the first electrode 14 and one bus bar 12 on the insulating film 18 on the left side of the figure. The bus bar 12 on the insulating film 18 is connected to the first electrode 14 on the right side of the drawing. The two bus bars 12 overlap at least partially in the third direction. The polarity of the bus bar 12 on the first electrode 14 and the bus bar 12 on the insulating film 18 have different polarities.

FIG. 7F shows a form in which one bus bar 12 is provided on the first electrode 14 on the left side of the figure and one bus bar 12 is provided on the first electrode 14 on the right side of the figure. The two bus bars 12 are arranged side by side in the second direction. The polarity of the bus bar 12 on the first electrode 14 on the left side of the figure and the polarity of the bus bar 12 on the first electrode 14 on the right side of the figure are different. In the form shown in the schematic views of FIGS. 7 (D), (E) and (F), the polarities of the first solar cell 11 are arranged in the same direction so that the polarities of the first submodule 11A are aligned. Ru. Further, in FIG. 7, the first solar cell 11 is exposed, and it is preferable to cover it with, for example, a resin.

(substrate)
As the substrate 13 of the embodiment, it is desirable to use soda lime glass, and general glass such as quartz, white plate glass, and chemically strengthened glass, or resins such as polyimide and acrylic can also be used.

(1st electrode)
The first electrode 14 of the embodiment is an electrode of the first solar cell 10. The first electrode 14 is, for example, a transparent electrode including a semiconductor film formed on the substrate 13. The first electrode 14 exists between the substrate 13 and the light absorption layer 15. The first electrode 14 may contain a thin metal film. As the first electrode 14, a semiconductor film containing at least indium tin oxide (ITO: Indium-Tin Oxide) can be used. A layer containing an oxide such as SnO ₂ , TIO ₂ , carrier-doped ZnO: Ga, or ZnO: Al may be laminated on the ITO on the light absorption layer 15 side. ITO and SnO ₂ may be laminated on the light absorption layer 15 side from the substrate 13 side, or ITO, SnO ₂ and TiO ₂ may be laminated on the light absorption layer 15 side from the substrate 13 side. The layer in contact with the light absorption layer of the first electrode 14 is preferably an oxide layer of any one of ITO, SnO ₂ and TiO ₂ . Further, a layer containing an oxide such as SiO ₂ may be further provided between the substrate 13 and ITO. The first electrode 14 can be formed into a film by sputtering onto the substrate 13. The film thickness of the first electrode 14 is, for example, 100 nm or more and 1000 nm or less. When the solar cell of the embodiment is used for a multi-junction type solar cell, the solar cell of the embodiment may exist on the top cell side or the middle cell side, and the first electrode 14 may be a translucent semiconductor film. preferable.

(Light absorption layer)
The light absorption layer 15 of the embodiment is a layer of any one or more of a compound semiconductor, a perovskite type compound, an oxide transparent semiconductor, and amorphous silicon. The light absorption layer 15 is a layer that forms a pn junction with the buffer layer 16. If the light absorption layer 15 is p-type, the buffer layer is n-type, and if the light absorption layer 15 is n-type, the buffer layer 16 is p-type. The light absorption layer 15 exists between the first electrode 14 and the buffer layer 16. When the light absorption layer 15 is homozygous, the buffer layer 16 may be omitted.

The light absorption layer 15 is, for example, Cu (In, Ga) Se ₂ , CuInTe ₂ , CuGaSe ₂ , Cu (In, Al) Se ₂ , Cu (Al, Ga) (S, Se) ₂ , CuGa (S, Se). ₂ , Ag (In, Ga) Se ₂ , Cu (In, Ga) (S, Se) ₂ and other compound semiconductor layers having a chalcopyrite structure, CdTe, (Cd, Zn, Mg) (Te, Se, S) and A compound semiconductor layer such as (In, Ga) ₂ (S, Se, Te) ₃ can be used as the light absorption layer. Further, examples of the compound semiconductor layer include a compound semiconductor layer having a kesterite structure or a stannite structure represented by CZTS (Cu ₂ ZnSnS ₄ ), a CdTe layer, and the like. The film thickness of the light absorption layer 15 is, for example, 800 nm or more and 3000 nm or less.

It is preferable to use an oxide transparent semiconductor such as Cu ₂ O for the light absorption layer 15.

Depending on the combination of elements, the size of the bandgap can be easily adjusted to the desired value. The target band gap value is, for example, 1.0 eV or more and 2.7 eV or less.

It is preferable that the bandgap value of the light absorption layer 15 on the top cell side is large from the viewpoint of increasing the amount of power generation in the second solar cell on the bottom cell side by widening the bandgap of the light absorption layer 15 on the top cell side. As the light absorption layer 15 having a larger band gap, Cu ₂ O, (Cd, Zn, Mg) (Te, Se, S), (In, Ga) ₂ (S, Se, Te) ₃ and the like absorb light. Suitable for layer 15.

As the light absorption layer 15, a perovskite type compound represented by CH ₃ NH ₃ PbX ₃ (X is at least one kind of halogen) or a layer of amorphous silicon can be used.

(Buffer layer)
The buffer layer 16 of the embodiment is an n-type or p-type semiconductor layer. The buffer layer 16 exists between the light absorption layer 15 and the second electrode 17. The buffer layer 16 is a layer that is physically in contact with the surface of the light absorption layer 15 opposite to the surface facing the first electrode 14 side. The buffer layer 16 is a layer that heterojunctions with the light absorption layer 15. The buffer layer 16 is preferably an n-type semiconductor or a p-type semiconductor whose Fermi level is controlled so that a solar cell having a high open circuit voltage can be obtained.

When the light absorption layer 15 is a chalcopyrite type compound, a kesterite type compound or a stanite type compound, the buffer layer 16 is, for example, Zn _{1- y} My O _1-x S _x , Zn _1-y-z Mg _z M. _y O, ZnO _1-x S _x , Zn _1-z Mg _z O (M is at least one element selected from the group consisting of B, Al, In and Ga), CdS and the like can be used. The thickness of the buffer layer 16 is preferably 2 nm or more and 800 nm or less. The buffer layer 16 is formed by, for example, sputtering or CBD (chemical solution precipitation method). When the buffer layer 16 is formed by CBD, for example, a metal salt (for example, CdSO ₄ ), a sulfide (thiourea) and a complexing agent (ammonia) can be formed on the light absorption layer 15 by a chemical reaction in an aqueous solution. When a chalcopyrite-type compound containing no In in Group IIIb elements such as CuGaSe ₂ layer, AgGaSe ₂ layer, CuGaAlSe ₂ layer, and CuGa (Se, S) ₂ layer is used for the light absorption layer 15, the buffer layer 16 is CdS. Is preferable.

When the light absorption layer 15 is CdTe, the buffer layer 16 is preferably n-type CdS, for example.

When the light absorption layer 15 is a perovskite type compound, the buffer layer 16 is an n-type layer called a so-called compact layer. The compact layer is preferably a layer of one or more oxides selected from titanium oxide, zinc oxide, gallium oxide and the like.

When the light absorption layer 15 is amorphous silicon, the buffer layer 16 has a wide gap and is easily formed in the process, so a—SiC: H or the like is preferable.

(Oxide layer)
The oxide layer of the embodiment is a thin film preferably provided between the buffer layer 16 and the second electrode 17. The oxide layer is a thin film containing any compound of Zn _1-x Mg _x O, ZnO _1-y S _y and Zn _1-x Mg _x O _1-y S _y (0≤x, y <1). be. The oxide layer may be in a form that does not cover all the surfaces of the buffer layer 16 facing the second electrode 17 side. For example, it may cover 50% of the surface of the buffer layer 16 on the second electrode 17 side. Other candidates include AlO _Z , SiO _Z , SiN _Z , Ultz-type AlN, GaN, and BeO. When the volume resistivity of the oxide layer is 1 Ωcm or more, there is an advantage that the leakage current derived from the low resistance component that may exist in the light absorption layer 15 can be suppressed. In the embodiment, the oxide layer can be omitted. These oxide layers are oxide particle layers, and it is preferable that the oxide layer has a large number of voids. The intermediate layer is not limited to the above compounds and physical properties, and may be any layer that contributes to the improvement of conversion efficiency of the solar cell. The intermediate layer may be a plurality of layers having different physical characteristics.

(2nd electrode)
The second electrode 17 of the embodiment is an electrode film that transmits light such as sunlight and has conductivity. The second electrode 17 is physically in contact with the surface of the intermediate layer and the buffer layer 16 opposite to the surface facing the light absorption layer 15. Between the second electrode 17 and the first electrode 14, there is a bonded light absorption layer 15 and a buffer layer 16. The second electrode 17 is formed by, for example, sputtering in an Ar atmosphere. As the second electrode 17, for example, ZnO: Al using a ZnO target containing 2 wt% of alumina (Al _{2O 3} ) or ZnO: B using B from diborane or triethylboron as a dopant can be used.

(3rd electrode)
The third electrode of the embodiment is an electrode of the first solar cell 11, and is a metal film formed on the second electrode on the side opposite to the light absorption layer 15 side. As the third electrode, a conductive metal film such as Ni or Al can be used. The film thickness of the third electrode is, for example, 200 nm or more and 2000 nm or less. Further, when the resistance value of the second electrode 17 is low and the series resistance component can be ignored, the third electrode may be omitted.

(Anti-reflective coating)
The antireflection film of the embodiment is a film for facilitating the introduction of light into the light absorption layer 15, and is formed on the second electrode 17 or on the side opposite to the light absorption layer 15 side on the third electrode. There is. As the antireflection film, it is desirable to use, for example, MgF ₂ or SiO ₂ . In the embodiment, the antireflection film can be omitted. It is necessary to adjust the film thickness according to the refractive index of each layer, but it is preferable to carry out vapor deposition at 70-130 nm (preferably 80-120 nm).

The manufacturing method of the first solar cell 11 and the side surfaces P1, P2, P3 of cutting by the patterns 1, 2, and 3 will be briefly described. A first electrode 14 is formed on the substrate 13, and the first electrode 14 is scribed to form a cross section of P1. Subsequently, the light absorption layer 15 and the buffer layer 16 are formed. The light absorption layer 15 is also formed on the cross section of P1. The light absorption layer 15 and the buffer layer 16 are scribed to form a cross section of P2. Subsequently, the second electrode 17 is formed on the buffer layer 16. The second electrode 17 is also formed on the cross section of P2. Then, when the light absorption layer 15, the buffer layer 16 and the second electrode 17 are scribed, a cross section of P3 is formed. Then, the first solar cell 11 connected in series is obtained. The bus bar 12 may be formed on the substrate before the film formation of the first electrode 14, or may be formed before and after the scribe treatment for forming the cross section of P3.

Since both the first electrode 14 and the second electrode 17 are transparent electrodes that transmit light, the resistance tends to be higher than that of the metal film electrode. Therefore, if the areas of the first electrode 14 and the second electrode 17 are large, the influence of the high resistance of the electrodes becomes remarkable. The small solar cell panel has a size of about 1200 mm x 600 mm, and the large one has a size of about 16000 mm x 1000 mm. Since the solar cell panel 10 has a large area, the first electrode 14 and the second electrode 17 per one of the first solar cell 11 also have a large area just by connecting them in series. In the embodiment, by electrically connecting the first submodule 11A in parallel, the area of the transparent electrode per cell or the width of one cell (width of the transparent electrode) can be reduced. If the area of the transparent electrode is reduced, the number of parallel connections increases accordingly, and the non-power generation region increases. Therefore, it is not preferable to make the area of the transparent electrode too small. Further, the electricity generated by the cell flows in the width direction (short direction), which is the second direction of the solar cell. Therefore, by shortening the distance in the width direction of the transparent electrode, the influence of the resistance of the transparent electrode can be alleviated. From these facts, the width of the first electrode 14, the width of the second electrode 17, or the width of the first electrode 14 and the second electrode 17 is preferably 3 mm or more and 15 mm or less, and more preferably 3.3 mm or more and 8 mm or less. , 3.5 mm or more and 8 mm or less is more preferable. The width of the first electrode 14 is the distance in the second direction of the surface of the first electrode 14 facing the substrate 13. Similarly, the width of the second electrode 17 is the distance in the second direction of the surface of the second electrode 17 facing the substrate 13.

(Third Embodiment)
The solar cell module of the third embodiment has a structure in which two or more solar cell panels are laminated. Two or more solar panels are electrically connected in parallel. As shown in the perspective conceptual diagram of FIG. 8, the solar cell module 102 according to the present embodiment has a first solar cell panel 10 and a second solar cell panel 20. The first solar cell panel 10 and the second solar cell panel 20 are laminated in the third direction. The first solar cell panel 10 and the second solar cell panel 20 are electrically connected in parallel. The first solar cell panel 10 has a bus bar 12 for connecting the first solar cell cells in the first solar cell panel 10 in parallel. Except for the number and position of the bus bars 12, the solar cell module 101 of the second embodiment and the solar cell module 101 of the second embodiment are common. The description common to the first embodiment and the second embodiment will be omitted.

When the bus bar 12 of the first solar cell panel 10 and the second solar cell 21 overlap each other, the amount of light received by the second solar cell 21 decreases. When the bus bar between the first submodules 11A exists on the non-power generation region which is the region between the plurality of second submodules 21A of the second solar cells 21 arranged in the second direction, the second solar cell 21 It is preferable because it has little effect on the amount of received light. The second solar cells 21 are all electrically connected in series. Therefore, if the amount of received light is reduced by the bus bar 12 in one cell, the output current is reduced as a whole, which is not preferable.

When the polarities of the first submodule 11A of the first solar cell panel 10 are staggered, the number of rows of the plurality of second submodules 21A of the second solar cell is n, and the number of about n is m. The number of bus bars is (n / m) + 1, and it is preferable that the bus bars 12 are arranged at equal intervals. Two of the bus bars 12 are present at both ends of the first solar cell panel 10 in the second direction. The remaining (n / m) -1 bus bar is a plurality of second submodules 21A of the second solar cell 21 arranged in the second direction, as shown in the schematic cross-sectional view of the solar cell module of FIG. It is preferably present on the non-power generation region of the second solar cell panel 20, which is the region between them. It is preferable that the bus bars 12 at both ends also exist on the non-power generation region of the second solar cell panel 20 in which the second solar cell 21 does not exist. The number of bus bars 12 varies depending on the number of parallel first submodules 11A of the first solar cell panel 10. Further, when the first solar cell 11 is arranged so that all the polarities of the first submodule 11A of the first solar cell panel 10 are aligned, the number of rows of the plurality of second submodules 21A of the second solar cell. Is n, and when the approximately number of n is m, the number of bus bars is 2 (n / m), and it is preferable that the bus bars 12 are arranged at equal intervals. Two of the bus bars 12 are present at both ends of the first solar cell panel 10 in the second direction. The remaining 2 (n / m) -2 bus bars are the non-power generation of the 2nd solar cell panel 20 which is the area between the plurality of 2nd submodules 21A of the 2nd solar cell 21 arranged in the 2nd direction. It is preferably present on the region. The first solar cell 11 is arranged so that the polarities of the second submodule 21A of the first solar cell panel 10 are partially aligned, and the first sun is arranged so that the polarities of the remaining first submodule 11A are staggered. When the battery cells 11 are arranged, the number of bus bars 12 is more than (n / m) +1 and less than 2 (n / m). It is preferable that the bus bars 12 at both ends also exist on the non-power generation region of the second solar cell panel 20 in which the second solar cell 21 does not exist. When these conditions are satisfied, all the bus bars 12 are provided on the non-power generation region of the second solar cell 21, which is preferable from the viewpoint of highly efficient power generation. The existence of the bus bar 12 on the non-power generation region of the second solar cell panel 20 means that the second solar cell 21 does not exist when the bus bar 12 is projected onto the second solar cell panel 20 in the third direction. The projected state of the bus bars 12 overlapping each other.

When the bus bar 12 is present on the non-power generation area of the second solar cell panel 20, the bus bar 12 on the non-power generation area of the second solar cell panel 20 is projected onto the second solar cell panel 20 in the third direction. It is preferable that the overlap distance with the second solar cell 21 is small. The overlapping distance O1 between the bus bar 12 and the second solar cell 21 is the _one represented as “+ Xmm” in FIG. The person represented by "-Ymm" does not overlap the bus bar 12 and the second solar cell 21, and represents the distance _O2 between the bus bar 12 and the second solar cell 21. The overlapping distance between the bus bar 12 and the second solar cell 21 is preferably 0 mm or more and 2 mm or less, and preferably 0 mm or more and 1 mm or less. Compared to the case where the overlapping region is 0 mm, when it is assumed that light perpendicular to the second solar cell panel 20 is incident at 1 mm, the power generation loss is preferably about 1%, which is preferable.

(Fourth Embodiment)
The solar cell module of the fourth embodiment has a first solar cell panel in which a plurality of first submodules including a plurality of first solar cell cells are electrically connected by a bus bar, and a first solar cell panel laminated with the first solar cell panel. 2 Has a solar cell panel. It is preferable that the two solar cell panels are electrically connected in parallel. FIG. 10 shows a schematic diagram of the first solar cell panel 20 of the fourth embodiment, and FIG. 11 shows a schematic diagram of the second solar cell panel 20 of the fourth embodiment. The panels of FIGS. 10 and 11 have a rectangular shape of the same size. The longitudinal direction of the first submodule 11A is the same as the longitudinal direction of the first solar cell in the first submodule 11A.

In the first solar cell panel 10 of FIG. 10, a first submodule 11A1 having a first direction as a longitudinal direction and a first submodule 11A2 having a second direction as a longitudinal direction are arranged. Bus bars 12 are connected between 11A of the first submodule and both ends thereof, and the electric power generated by the first submodule is taken out by the bus bar 12. In the schematic diagram of FIG. 10, a plurality of sets in which the two first submodules 11A are electrically connected in parallel by the bus bar 12 are shown. A plurality of sets in which the two first submodules 11A and the bus bar 12 are connected are electrically connected in parallel. Although the electrical connection between the bus bars 12 is not shown in the schematic diagram of FIG. 10, the bus bars 12 are connected in the same manner as the solar cell panels 10 of the second embodiment and the third embodiment. The orientation and number of the first submodule 11A can be appropriately selected according to the size and shape of the panel.

In the second solar cell panel 20 of FIG. 11, the second submodules 21A1, 21A2 having the first direction as the longitudinal direction and the second submodule 21A3 having the second direction as the longitudinal direction are arranged. The second solar cell 21 is electrically connected (solid line) in series in the longitudinal direction of each submodule. The second submodule 21A is configured to be electrically connected in series. The orientation and number of the second submodule 21A can be appropriately selected according to the size and shape of the panel.

The bus bar 12 of the first solar cell panel 10 exists on a non-power generation region in which the second solar cell 21 of the second solar cell panel 20 is not provided. Even if the sizes and orientations of the submodules are not aligned and the orientations of the bus bars 12 are not aligned, the bus bar 12 is unlikely to be in the shadow of the second solar cell 21. The first solar cell panel 10 can be configured so as to increase the arrival of light in the power generation region of the second solar cell panel 20. Even in such a configuration, the generated voltages of the first solar cell panel 10 and the second solar cell panel 20 can be made uniform, and the first solar cell panel 10 and the second solar cell panel 20 can be connected in parallel with low loss.

(Fifth Embodiment)
The solar cell module of the fifth embodiment has a first solar cell panel in which a plurality of first submodules including a plurality of first solar cell cells are electrically connected by a bus bar, and a first solar cell panel laminated with the first solar cell panel. 2 Has a solar cell panel. The solar cell module of the fifth embodiment is a modification of the solar cell module of the fourth embodiment. It is preferable that the two solar cell panels are electrically connected in parallel. FIG. 12 shows a schematic diagram of the first solar cell panel 20 of the fifth embodiment, and FIG. 13 shows a schematic diagram of the second solar cell panel 20 of the fifth embodiment. The panels of FIGS. 12 and 13 have a polygonal shape of the same size. When arranging the solar cell module on a roof or the like, if the area to be arranged is not rectangular, the installation area of the solar cell module can be efficiently expanded by using the module of the present embodiment.

The solar cell module of the fifth embodiment is common to the solar cell module of the fourth embodiment except that the shape of the panel and the arrangement or configuration of the submodules are different.

If the panel shape is polygonal, if the submodules are arranged as in the fourth embodiment, the submodules will partially protrude from the panel. Therefore, as shown in the schematic views of FIGS. 12 and 13, the submodules The arrangement and composition are changed.

In the first solar cell panel 10 shown in the schematic view of FIG. 12, the polygonal shape and the arrangement of the submodules are matched by moving the first submodule 11A1 on the upper side of the drawing to the lower side of the drawing. As shown in FIG. 12, the separated first submodule 11A1 may also be electrically connected by the bus bar 12.

In the second solar cell panel 20 shown in the schematic view of FIG. 13, the second submodule composed of the three solar cell 21 on the upper side of the drawing is removed, and one is placed on each of the three second submodules 21A3 on the lower side of the drawing. It is a form reconstructed so that one solar cell 21 is added.

Even if the solar cell panels of FIGS. 12 and 13 are overlapped with each other, the bus bar 12 of the first solar cell panel 10 is not provided with the second solar cell 20 of the second solar cell panel 20, as in the fourth embodiment. It exists on the non-power generation area. Even if the sizes and orientations of the submodules are not aligned and the orientations of the bus bars 12 are not aligned, the bus bar 12 is unlikely to be in the shadow of the second solar cell 21. The first solar cell panel 10 can be configured so as to increase the arrival of light in the power generation region of the second solar cell panel 20. Even in such a configuration, the generated voltages of the first solar cell panel 10 and the second solar cell panel 20 can be made uniform, and the first solar cell panel 10 and the second solar cell panel 20 can be connected in parallel with low loss.

(Sixth Embodiment)
The solar cell modules 100, 101, 102 of the embodiment, the solar cell module of the fourth embodiment and the solar cell module of the fifth embodiment are used as a generator for generating power in the solar power generation system of the sixth embodiment. Can be done. The solar power generation system of the embodiment uses a solar cell module to generate electricity. Specifically, the solar cell module that generates electric power, the means for converting the generated electricity into electric power, and the generated electricity are used. It has a storage means for storing electricity or a load for consuming the generated electricity. FIG. 14 shows a conceptual diagram of the configuration of the photovoltaic power generation system 200 of the embodiment. The photovoltaic power generation system of FIG. 14 has a solar cell module 201 (100, 101, 102), a converter 202, a storage battery 203, and a load 204. Either the storage battery 203 or the load 204 may be omitted. The load 204 may be configured so that the electric energy stored in the storage battery 203 can be used. The converter 202 is a device including a circuit or element that performs power conversion such as transformation or DC / AC conversion, such as a DC-DC converter, a DC-AC converter, and an AC-AC converter. As the configuration of the converter 202, a suitable configuration may be adopted according to the output voltage, the configuration of the storage battery 203 and the load 204.

The solar cell included in the received solar cell module 201 generates electricity, and the electric energy is converted by the converter 202 and stored in the storage battery 203 or consumed by the load 204. The solar cell module 201 is provided with a solar tracking drive device for always directing the solar cell module 201 toward the sun, a condenser for condensing sunlight, a device for improving power generation efficiency, and the like. It is preferable to add it.

The photovoltaic power generation system 200 is preferably used for real estate such as residences, commercial facilities and factories, and is preferably used for movables such as vehicles, aircraft and electronic devices. It is expected that the amount of power generation will be increased by using the photoelectric conversion element having excellent conversion efficiency of the embodiment for the solar cell module 201.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.
(Example 1)
In Example 1, Cu _0.95 GaSe _1.95 S _0.05 is used for the light absorption layer of the first solar cell of the first solar cell panel, and the light absorption of the second solar cell of the second solar cell panel is used. Polycrystalline Si is used for the layer. The first solar cell panel and the second solar cell panel have a size of 1650 mm in the first direction and 991 mm in the second direction. The first solar cell has the same width of 3.94 mm (the width of the second electrode of the cell is also the same), and 246 rows are provided in the second direction. Sixty-one first submodules are formed by electrically connecting 41 cells in series. A total of seven 3 mm bus bars are provided between the six first submodules 11A and at both ends, and are electrically connected in parallel. The bus bar is arranged so as not to overlap with the second solar cell. Ten second solar cells are arranged in the first direction, and six rows of second submodules 21A to which these are connected in series are arranged in the second direction. Six second submodules 21A are also connected in series, and 60 second solar cells are connected in series.

First, Jsc, Voc, and conversion efficiency are obtained separately for the first solar cell panel and the second solar cell panel, and then the first solar cell panel and the second solar cell panel are laminated and electrically parallel to each other. Find the conversion efficiency of the connected solar cell module. The results of other examples and comparative examples are also summarized in Table 1.

(Example 2)
The bus bar is the same as that of the first embodiment except that the bus bar of the first solar cell panel and the first solar cell are arranged so as to overlap the second solar cell by 1 mm.

(Example 3)
The bus bar is the same as that of the first embodiment except that the bus bar of the first solar cell panel and the first solar cell are arranged so as to overlap the second solar cell by 2 mm.

(Example 4)
The first solar cell has the same width of 4.74 mm (the width of the second electrode of the cell is also the same), and 205 rows are provided in the second direction. The 41 cells are electrically connected in series to form five first submodules 11A. A total of six bus bars are provided between the five first submodules 11A and at both ends. It is the same as the first embodiment except that the bus bar of the first solar cell panel and the first solar cell are arranged so as to overlap the second solar cell by 2 mm or less.

(Example 5)
The first solar cell has the same width of 7.95 mm (the width of the second electrode of the cell is also the same), and 123 rows are provided in the second direction. The 41 cells are electrically connected in series to form three first submodules 11A. It is the same as the first embodiment except that a total of four bus bars are provided between the three first submodules 11A and at both ends, and the bus bar of the first solar cell panel and the first solar cell are arranged.

(Example 6)
The first solar cell has the same width of 11.96 mm (the width of the second electrode of the cell is also the same), and 82 rows are provided in the second direction. The 41 cells are electrically connected in series to form two first submodules 11A. It is the same as the first embodiment except that a total of three bus bars are provided between the two first submodules 11A and at both ends, and the bus bar of the first solar cell panel and the first solar cell are arranged.

(Example 7)
The first solar cell has the same width of 3.73 mm (the width of the second electrode of the cell is also the same), and 240 rows are provided in the second direction. Six first submodules 11A are formed by electrically connecting 40 cells in series. It is the same as the first embodiment except that a total of five bus bars are provided between the six first submodules 11A and both ends thereof, and the bus bars of the first solar cell panel and the first solar cell are arranged.

(Comparative Example 1)
The first solar cell is a single row of cells having a width of 985 mm (the width of the second electrode of the cell is also the same). It is the same as the first embodiment except that a total of two bus bars are provided at both ends of the first solar cell panel and the bus bar of the first solar cell panel and the first solar cell are arranged.

(Comparative Example 2)
The first solar cell has the same width of 24 mm (the width of the second electrode of the cell is also the same), and 41 rows are provided in the second direction. 41 cells are electrically connected in series to form one first submodule 11A. It is the same as the first embodiment except that a total of two bus bars are provided at both ends of the first solar cell panel and the bus bar of the first solar cell panel and the first solar cell are arranged.

(Example 8)
Cu _0.93 GaSe ₂ is used for the light absorption layer of the first solar cell of the first solar cell panel. The first solar cell has the same width of 3.75 mm (the width of the second electrode of the cell is also the same), and 258 rows are provided in the second direction. Sixty-one cells are electrically connected in series to form six first submodules 11A. A total of seven 3 mm bus bars are provided between the six first submodules 11A and at both ends, and are electrically connected in parallel. The bus bar is arranged so as not to overlap with the second solar cell. Other than these things, it is the same as in Example 1.

(Example 9)
A perovskite compound is used for the light absorption layer of the first solar cell of the first solar cell panel. The first solar cell has the same width of 4.36 mm (the width of the second electrode of the cell is also the same), and 222 rows are provided in the second direction. Sixty-seven first submodules 11A are formed by electrically connecting 37 cells in series. A total of seven 3 mm bus bars are provided between the six first submodules 11A and at both ends, and are electrically connected in parallel. The bus bar is arranged so as not to overlap with the second solar cell. Other than these things, it is the same as in Example 1.

(Example 10)
Amorphous silicon is used for the light absorption layer of the first solar cell of the first solar cell panel. The first solar cell has the same width of 3.83 mm (the width of the second electrode of the cell is also the same), and 252 rows are provided in the second direction. Sixty-two cells are electrically connected in series to form six first submodules 11A. A total of seven 3 mm bus bars are provided between the six first submodules 11A and at both ends, and are electrically connected in parallel. The bus bar is arranged so as not to overlap with the second solar cell. Other than these things, it is the same as in Example 1.

(Example 11)
A CdTe compound is used for the light absorption layer of the first solar cell of the first solar cell panel. The first solar cell has the same width of 3.5 mm (the width of the second electrode of the cell is also the same), and 276 rows are provided in the second direction. Sixty-four cells are electrically connected in series to form six first submodules 11A. A total of seven 3 mm bus bars are provided between the six first submodules 11A and at both ends, and are electrically connected in parallel. The bus bar is arranged so as not to overlap with the second solar cell. Other than these things, it is the same as in Example 1.

From the examples, it can be seen that a panel that exceeds the efficiency of Si alone (even at present) can be obtained. There is room for improvement in the efficiency of CGSS and CGS cells. As the efficiency improves, so does the open circuit voltage, so it is necessary to consider it again, including the number of series. In addition, since the efficiency of the bottom Si solar cell is improving day by day, a highly efficient module can be obtained by superimposing highly efficient panels on top of each other.

Further, as a light absorbing layer of the first solar cell, as a solar cell such as Cu ₂ O, (Cd, Zn, Mg) (Te, Se, S) or (In, Ga) ₂ (S, Se, Te) ₃ . By using a light absorbing layer having a very wide band gap, the band gap difference from the light absorbing layer can be made larger in the second solar cell on the bottom side. The larger the bandgap difference, the more light that contributes to the power generation of the light absorption layer of the second solar cell reaches and the amount of power generation increases. By adopting a multi-junction solar cell having such a large bandgap difference and adopting the connection form of the embodiment, the amount of power generation in the second solar cell panel on the bottom cell side is increased, and the multi-junction solar cell is used. Further increase in power generation in batteries is expected.
In the specification, some of the elements are represented only by element symbols.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments as they are, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, components over different embodiments may be appropriately combined as in the modified example.

100, 101, 102 ... solar cell, 10 ... first solar cell panel, 11 ... first solar cell, 11A ... first submodule, 12 ... bus bar, 13 ... substrate, 14 ... first electrode, 15 ... light absorption Layer, 16 ... Buffer layer, 17 ... Second electrode, 18 ... Insulation film, 20 ... Second solar cell panel, 21 ... Second solar cell, 21A ... Second submodule, 200 ... Solar cell system, 201 ... Sun Battery module, 202 ... converter, 203 ... storage battery, 204 ... load

Claims (13)

A first solar cell panel having a plurality of first submodules including a plurality of first solar cell cells,
It has a second solar cell panel that is laminated with the first solar cell panel and has a plurality of second submodules including a plurality of second solar cell cells.
The first solar cell panel exists on the light incident side and is present.
The first solar cell panel and the second solar cell panel are electrically connected in parallel, and the first solar cell panel and the second solar cell panel are electrically connected in parallel.
The plurality of first solar cells included in the plurality of first submodules are electrically connected in series.
The plurality of first submodules are electrically connected in parallel, and the plurality of first submodules are electrically connected in parallel.
The plurality of second solar cells included in the plurality of second submodules are electrically connected in series.
A solar cell module in which the plurality of second submodules are electrically connected in series. The plurality of first solar cell cells have a structure in which the first direction is the longitudinal direction.
The solar cell module according to claim 1, wherein the first submodule is electrically connected in parallel in a second direction intersecting the first direction. The solar cell module according to claim 1 or 2, wherein the difference between the output voltages of the first solar cell panel and the second solar cell panel is 2.0 V or less. The plurality of first solar cells according to any one of claims 1 to 3, wherein one or more of a compound semiconductor, a perovskite type compound, an oxide transparent semiconductor and amorphous silicon is used for the light absorption layer. The listed solar cell module. The plurality of second solar cells have a light absorbing layer using crystalline Si, polycrystalline Si, or a perovskite type compound.
The solar cell according to any one of claims 1 to 4, wherein the bandgap of the light absorption layer of the plurality of second solar cells is a narrower bandgap than the light absorption layer of the plurality of first solar cells. module. The solar cell module according to claim 2, wherein the plurality of first submodules are connected by a bus bar having the first direction as a longitudinal direction. The second solar cell panel has a plurality of second submodules including the plurality of second solar cell cells.
The second solar cell of the plurality of second submodules is electrically connected in series in the first direction.
The plurality of second submodules are present in a plurality of rows in the second direction.
The plurality of second submodules are electrically connected in series, and the plurality of second submodules are electrically connected in series.
When the polarities of the plurality of first submodules are staggered
When the number of parallels in the plurality of second submodules is n and the divisor of n is m, the number of the bus bars is (n / m) + 1.
The solar cell module according to claim 6, wherein the bus bar exists on a non-power generation region of the second solar cell panel. The second solar cell panel has a plurality of second submodules including the plurality of second solar cell cells.
The solar cell module according to claim 2 or 6 , wherein the second solar cell included in the plurality of second submodules is electrically connected in series. The second solar cell of the second submodule is electrically serialized in the first direction.
The solar cell module according to claim 8, wherein the plurality of second submodules are arranged in a plurality of rows in the second direction. The solar cell module according to claim 6 or 7, wherein the distance between the bus bar and the second solar cell is 0 mm or more and 2 mm or less. The solar cell module according to any one of claims 6, 7 and 10, wherein the bus bar is also present at both ends of the first solar cell panel. A first solar cell panel in which a plurality of first submodules including a plurality of first solar cell cells are electrically connected by a bus bar, and a first solar cell panel.
A solar cell module having a second solar cell panel laminated with the first solar cell panel. A photovoltaic power generation system using the solar cell module according to any one of claims 1 to 12.

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