Solar cell module

Abstract

To attain sufficient reductions in manufacturing and material costs while eliminating reductions in power-generating area and the concentration of current in a bypass diode, and to also respond sufficiently to the diversification and generalization of device structures and applications, a solar cell module (1) according to the present disclosure comprises: a plurality of solar cells (10) having a power-generating element layer (12) on a first conductive substrate; and one or more bypass diodes (50) having a diode element layer (52) on a second conductive substrate. Each power-generating element layer (12) in the solar cells (10) is disposed on one side of the first conductive substrate, while each diode element layer (52) in the bypass diodes (50) is disposed on the other side of the first conductive substrate. A set of parallel circuits is formed by connecting the bypass diodes (50) in parallel with a set of strings formed by the plurality of solar cells (10) being connected in series.

Description

solar cell module

[0001] The present disclosure relates to a solar cell module including a plurality of solar cells and one or more bypass diodes.

[0002] Generally, if a part of a string in which multiple solar cells are connected in series is shaded by, for example, a wall or a vehicle, power generation in that part stops and the current is cut off, and unless some measures are taken, power generation in the entire string will stop. Furthermore, resistance in the shaded part increases, which can cause localized heat generation, potentially resulting in malfunctions and other problems. To prevent such adverse effects, bypass diodes must be incorporated into each solar cell or string to divert the generated current. In particular, it is desirable to incorporate a relatively large number of bypass diodes in solar cell modules installed in environments that are heavily affected by shadows.

[0003] To meet such demands, for example, Patent Document 1 describes a solar cell module that includes solar cells formed on a transparent substrate that serves as the light-receiving surface, and bypass diodes formed on top of the solar cells. This configuration is intended to prevent a decrease in the light-receiving surface area of ​​the solar cells, while making the area of ​​the bypass diodes relatively large and suppressing heat generation due to current concentration.

[0004] Japanese Patent Application Laid-Open No. 2005-268719

[0005] However, in the conventional solar cell modules, since the bypass diodes are stacked on the solar cells, the manufacturing process cannot be sufficiently simplified to provide large-area bypass diodes, and the manufacturing costs and material costs cannot be sufficiently reduced. Furthermore, the configuration of the conventional solar cell module cannot use an opaque substrate to ensure a light-receiving surface, which means that it is not possible to fully respond to the diversification and versatility of device structures and applications.

[0006] Therefore, the present disclosure has been made in consideration of the above circumstances, and aims to provide a solar cell module that can sufficiently reduce manufacturing costs and material costs while eliminating a reduction in power generation area and current concentration in the bypass diode by realizing a large area for the bypass diode without compromising the light-receiving area of ​​the solar cell. Another aim of the present disclosure is to provide a solar cell module that can sufficiently accommodate diversification and versatility of device structures and applications.

[0007] In order to solve the above problems, a solar cell module according to an example of the present disclosure includes a plurality of solar cells each having a power generation element layer formed on a first conductive substrate, and one or more bypass diodes each having a diode element layer formed on a second conductive substrate. The power generation element layers of the plurality of solar cells are disposed on one side of the first conductive substrate, and the diode element layers of the one or more bypass diodes are disposed on the other side of the first conductive substrate. Furthermore, a set of parallel circuits is formed by connecting one or more bypass diodes in parallel to a set of strings formed by connecting a plurality of solar cells in series.

[0008] In a solar cell module having such a configuration, power is generated by receiving light from one side of the first conductive substrate on which the power generation element layer of the solar cell is provided. Furthermore, since the diode elements of the bypass diodes are disposed on the other side (non-light-receiving side) of the first conductive substrate, the bypass diodes do not block incident light on the solar cell, preventing a reduction in the light-receiving area. Furthermore, such a structure facilitates the enlargement of the bypass diodes, effectively eliminating current concentration in the bypass diodes. As a result, light energy can be effectively utilized even in environments susceptible to shadows, such as on building walls or in automotive applications. Furthermore, since it is not necessary to stack the bypass diodes on the solar cell, both manufacturing costs and material costs can be significantly reduced. Additionally, such a structure allows the use of opaque substrates as the first conductive substrate and the second conductive substrate, contributing to the diversification and generalization of device structures and applications.

[0009] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a solar cell in a first embodiment of the solar cell module of the present disclosure. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a bypass diode in the first embodiment of the solar cell module of the present disclosure. FIG. 3 is (A) a schematic side view and (B) a schematic plan (bottom) view showing an example of the configuration of a first embodiment of the solar cell module of the present disclosure. FIG. 4 is (A) a schematic side view and (B) a schematic plan (bottom) view showing an example of the configuration of a second embodiment of the solar cell module of the present disclosure. FIG. 5 is a schematic side view and (B) a schematic plan (bottom) view showing an example of the configuration of a third embodiment of the solar cell module of the present disclosure. FIG. 6 is a schematic side view and (B) a schematic plan (bottom) view showing an example of the configuration of a fourth embodiment of the solar cell module of the present disclosure. FIG. 7 is a schematic plan (bottom) view showing an example of the configuration of a fifth embodiment of the solar cell module of the present disclosure. FIG. 8 is a schematic plan (bottom) view showing an example of the configuration of a sixth embodiment of the solar cell module of the present disclosure. FIG. 9 is a schematic plan (bottom) view showing an example of the configuration of a seventh embodiment of the solar cell module of the present disclosure.

[0010] <Definitions of Terms, etc.> A solar cell module according to a preferred embodiment of the present disclosure will be described below with reference to the accompanying drawings. For convenience, in this specification, for both the solar cell and the bypass diode in the solar cell module, the direction in which each layer is stacked relative to the substrate will be referred to as "upward," the opposite direction will be referred to as "downward," and the coordinate axis direction will be referred to as "upward" (which may differ from the upward and downward directions in the drawings). The left side of the illustration will be simply referred to as "leftward" or "left," and the right side of the illustration will be simply referred to as "rightward" or "right." Furthermore, in this specification, when each layer or the semiconductor contained in each layer is referred to by the name of a compound, this includes not only the pure compound itself, but also compounds doped with trace amounts of elements or chemical species to the extent that the properties of the compound are not lost. Furthermore, in this specification, because elements in each layer can exist in different oxidation states, all oxidation states will be referred to by the name of the element unless otherwise clearly stated. For example, "elemental hydrogen" and its chemical symbol "H" may refer to a hydrogen atom, a hydrogen ion, a hydride ion, a hydrogen radical, hydrogen in a compound, and hydrogen in an elemental state.

[0011] <First embodiment> Fig. 1 is a schematic cross-sectional view showing an example of the configuration of a solar cell in a solar cell module according to a first embodiment of the present disclosure. As shown in Fig. 1, a solar cell 10 in a solar cell module 1 has electrodes 11 and 13 and a power generation element layer 12 provided therebetween. A solar cell 10 having such a layered structure typically receives light from the upper surface side of the electrode 13 and generates power.

[0012] (Electrode 11) The electrode 11 is composed of a conductive substrate 111 (first conductive substrate) and a lower electrode layer 112 formed thereon. The material for forming the conductive substrate 111 is not particularly limited, and examples thereof include metal substrates such as titanium foil, stainless steel foil, and aluminum foil, and conductive resin films, and the thickness thereof is preferably, for example, approximately 10 to 500 μm. The lower electrode layer 112 is also not particularly limited, and examples thereof include metal conductive layers made of Mo, Cr, Ti, etc., conductive inorganic compound conductive layers other than metals, and conductive organic compound conductive layers. The thickness of the lower electrode layer 112 is also not particularly limited, and is preferably, for example, approximately 200 to 800 nm.

[0013] (Power Generation Element Layer 12) The power generation element layer 12 is composed of a p-type hole transport layer 121, a light absorption layer 122, and an n-type electron transport layer 123, which are stacked in this order on the lower electrode layer 112 of the electrode 11. The material for forming the p-type hole transport layer 121 is not particularly limited, and examples thereof include inorganic compounds such as molybdenum selenide and molybdenum oxide, and organic compounds such as fluorene derivatives. These may be used alone or in combination of two or more. The thickness of the p-type hole transport layer 121 is also not particularly limited, and is preferably, for example, about 20 to 100 nm. The material for forming the light absorption layer 122 is not particularly limited, and examples thereof include (Cs, FA)PbI ３ Perovskite compounds such as Cu(In,Ga)(Se,S) ２ chalcopyrite compounds such as Cu ２ ZnSnS ４These may be used alone or in combination of two or more. The thickness of the light absorbing layer 122 is not particularly limited, and is preferably, for example, about 1 to 5 μm. Furthermore, the material for forming the n-type electron transport layer 123 is not particularly limited, and may be, for example, Zn(O,S,OH)x, CdS, In ２ S ３ , ZnTiOx, etc., which may be used alone or in combination of two or more. The thickness of the n-type electron transport layer 123 is not particularly limited, and is preferably, for example, about 20 to 150 nm.

[0014] (Electrode 13) The electrode 13 is composed of an upper electrode layer 131 and a grid electrode 132, which are stacked in this order on the n-type electron transport layer 123 of the power generation element layer 12. The upper electrode layer 131 is not particularly limited, and examples thereof include transparent electrode layers made of ITO, IOH, FTO, ZnO:B, ZnO:Al, etc. The thickness of the upper electrode layer 131 is not particularly limited, and is preferably, for example, approximately 0.1 to 2 μm. The grid electrode 132 is not particularly limited, and examples thereof include metal conductive layers made of Mo, Cr, Ag, etc., conductive inorganic compound conductive layers other than metals, and conductive organic compound conductive layers. The thickness of the grid electrode 132 is also not particularly limited, and is preferably, for example, approximately 5 to 50 μm.

[0015] 2 is a schematic cross-sectional view showing an example of the configuration of a bypass diode in the solar cell module according to the first embodiment of the present disclosure. As shown in FIG. 2, the bypass diode 50 in the solar cell module 1 has electrodes 51 and 53 and a diode element layer 52 provided therebetween.

[0016] (Electrode 51, Diode Element Layer 52, Electrode 53) Similar to the electrode 11 described above, the electrode 51 is composed of a conductive substrate 511 (second conductive substrate) laminated in this order on the lower electrode layer 512 of the electrode 51, and a lower electrode layer 512 formed thereon. The conductive substrate 511 and the lower electrode layer 512 may be configured similarly to the conductive substrate 111 and the lower electrode layer 112, respectively. Similarly to the power generation element layer 12 described above, the diode element layer 52 is composed of a p-type hole transport layer 521, a p-type semiconductor layer 522, and an n-type electron transport layer 523 laminated in this order on the lower electrode layer 512 of the electrode 51. The p-type hole transport layer 521, the p-type semiconductor layer 522, and the n-type electron transport layer 523 may be configured similarly to the p-type hole transport layer 121, the light absorption layer 122, and the n-type electron transport layer 123, respectively. Furthermore, like the electrode 13 described above, the electrode 53 is composed of an upper electrode layer 531 and a solid electrode 532, which are sequentially stacked on the n-type electron transport layer 523 of the diode element layer 52. The upper electrode layer 531 and the solid electrode 532 may be made of the same materials as the upper electrode layer 131 and the grid electrode 132, respectively. As described above, the bypass diode 50 may be a device having a configuration substantially equivalent to that of the solar cell 10, and the power generating element layer 12 and the diode element layer 52 may contain the same material or materials of the same kind. Furthermore, in the bypass diode 50, a notch C is formed in the right end portions of the diode element layer 52 and the electrode 53, exposing the right end portion of the upper surface of the lower electrode layer 512 of the electrode 51. The method for forming the notch C is not particularly limited, and for example, scribing, etching, patterning, or the like may be appropriately selected and applied.

[0017] 3A and 3B are schematic side and bottom views, respectively, showing an example of the configuration of a solar cell module according to a first embodiment of the present disclosure. The solar cell module 1 includes two rectangular solar cells 10 and one rectangular bypass diode 50. In the solar cell module 1, the solar cells 10 are connected in series via a conductive adhesive layer B1 to form a string. More specifically, the right end of the upper surface of the grid electrode 132 of the electrode 13 of the left solar cell 10 and the left end of the lower surface of the conductive substrate 111 of the electrode 11 of the right solar cell 10 are joined by the conductive adhesive layer B1 so as to overlap each other.

[0018] In the solar cell module 1, a bypass diode 50 is connected in parallel to a string including solar cells 10, 10 via conductive adhesive layers B2, B3 to form a parallel circuit. More specifically, substantially the entire lower surface of the conductive substrate 111 of the electrode 11 of the right-side solar cell 10 and the entire upper surface of the electrode 53 of the bypass diode 50 are joined by the conductive adhesive layer B2 so as to overlap each other. In addition, the left end of the lower surface of the conductive substrate 111 of the electrode 11 of the right-side solar cell 10 and the right end of the upper surface of the lower electrode layer 512 of the electrode 51 exposed by the cutout C in the bypass diode 50 are joined by the conductive adhesive layer B3 so as to overlap each other.

[0019] As described above, in the solar cell module 1, the solar cells 10 are connected along their short sides (the vertical direction in FIG. 3A ) so that portions of each are stacked in order. The bypass diode 50 is arranged so as to extend longitudinally across the solar cells 10 and overlap along the stacking direction of the solar cells 10. In other words, the power generation element layers 12 of each of the solar cells 10 are arranged on one side of the conductive substrate 111, and the diode element layer 52 of the bypass diode 50 is arranged on the other side (non-light-receiving side) of the conductive substrate 111. The portions where the conductive adhesive layer B1 is provided are electrical contacts between the solar cells 10, and the portions where the conductive adhesive layers B2 and B3 are provided are electrical contacts between the solar cells 10 and the bypass diode 50. The solar cells 10 and the bypass diode 50 are insulated from each other by an air layer or an appropriate insulating layer at locations other than the electrical contacts.

[0020] The solar cell module 1 configured in this manner receives light from one side of the conductive substrate 111 (first conductive substrate) on which the power generation element layer 12 of the solar cell 10 is provided, and generates electricity. Furthermore, the diode element layer 52 of the bypass diode 50 is disposed on the other side (non-light-receiving side) of the conductive substrate 111. This prevents the bypass diode 50 from blocking incident light on the solar cell 10, thereby preventing a reduction in the light-receiving area. This structure also facilitates the large area of ​​the bypass diode 50, eliminating current concentration in the bypass diode 50. As a result, light energy can be effectively utilized even in environments susceptible to shadows, such as on the wall of a building or in an automotive application. Furthermore, there is no need to stack the bypass diode 50 on the solar cell 10. Furthermore, the solar cell 10 and the bypass diode 50 can be easily bonded together using the conductive adhesive layers B1 to B3. This significantly reduces both manufacturing and material costs. In addition, such a structure allows the use of opaque substrates as the conductive substrate 111 and the conductive substrate 511, which can further contribute to diversifying and generalizing device structures and applications.

[0021] Furthermore, in the solar cell module 1, both the solar cell 10 and the bypass diode 50 can be configured as a layered structure made of materials that are easy to thin, which is useful from the perspective of making the solar cell module 1 thinner and more flexible. Furthermore, since a string is formed by connecting portions of the solar cells 10 in a stacked manner, the solar cell module 1 can be made even thinner and more flexible. Furthermore, since the bypass diode 50 is arranged across multiple (two) solar cells 10, the area of ​​the bypass diode 50 can be effectively increased. Furthermore, since the bypass diode 50 is arranged so as to overlap in the stacking direction of the solar cells 10, this can also contribute to making the solar cell module 1 more compact.

[0022] Furthermore, a notch C is formed in the diode element layer 52 of the bypass diode 50, and the bypass diode 50 is connected to one of the solar cell 10, 10 at the notch C. This makes it easier to join the solar cell 10 and the bypass diode 50, contributing to further cost reduction. Furthermore, because both the power generation element layer 12 and the diode element layer 52 contain the same material or similar materials, such as a chalcopyrite compound, the solar cell 10 and the bypass diode 50 can be used interchangeably, further reducing manufacturing costs and management costs. In addition, because the solar cell 10 and the bypass diode 50 are insulated except at their electrical contacts, short circuits between them are sufficiently suppressed, contributing to improved reliability of the solar cell module 1.

[0023] 4A and 4B are a schematic side view and a schematic plan (bottom) view showing an example of the configuration of a solar cell module according to a second embodiment of the present disclosure. Solar cell module 2 has the same configuration as solar cell module 1, except that it includes three solar cell cells 10, 10, 10, and includes a bypass diode 60 instead of bypass diode 50. Here, bypass diode 60 has electrodes 61 and 63 and a diode element layer 62 provided therebetween. These electrode 61, diode element layer 62, and electrode 63 can be configured in the same manner as electrode 51, diode element layer 52, and electrode 53 of bypass diode 50 described above, respectively.

[0024] In the solar cell module 2, solar cells 10, 10, 10 are connected in series via conductive adhesive layers B1, B1 to form a string. More specifically, the right end of the upper surface of the grid electrode 132 of the electrode 13 of the left solar cell 10 and the left end of the lower surface of the conductive substrate 111 of the electrode 11 of the central solar cell 10 are joined by the conductive adhesive layer B1 so as to overlap each other. Similarly, the right end of the upper surface of the grid electrode 132 of the electrode 13 of the central solar cell 10 and the left end of the lower surface of the conductive substrate 111 of the electrode 11 of the right solar cell 10 are joined by the conductive adhesive layer B1 so as to overlap each other.

[0025] In the solar cell module 2, a bypass diode 60 is connected in parallel to a string including solar cells 10, 10, 10 via conductive adhesive layers B2 and B3 to form a parallel circuit. More specifically, substantially the entire lower surface of the conductive substrate 111 of the electrode 11 of the left solar cell 10 and substantially the left half of the upper surface of the electrode 63 of the bypass diode 60 are joined by the conductive adhesive layer B2 so as to overlap each other. Furthermore, the left end of the lower surface of the conductive substrate 111 of the electrode 11 of the right solar cell 10 and the right end of the upper surface of the lower electrode layer of the electrode 61 exposed by the cutout C of the bypass diode 60 are joined by the conductive adhesive layer B3 so as to overlap each other.

[0026] As described above, in the solar cell module 2, the solar cells 10 are connected along their short sides (the vertical direction in FIG. 4A ) so that parts of each are stacked in order. The bypass diode 60 is a longer member than the bypass diode 50, and is arranged so as to extend longitudinally across the solar cells 10 and overlap along the stacking direction of the solar cells 10. In other words, the power generation element layers 12 of each of the solar cells 10 are arranged on one side of the conductive substrate 111, and the diode element layer 62 of the bypass diode 60 is arranged on the other side (non-light-receiving side) of the conductive substrate 111. The portions where the conductive adhesive layers B1 are provided serve as electrical contacts between the solar cells 10, and the portions where the conductive adhesive layers B2 and B3 are provided serve as electrical contacts between the solar cells 10 and the bypass diode 60. The solar cells 10, 10, 10 are insulated from the bypass diode 50 by an air layer or an appropriate insulating layer other than the electrical contacts. For example, an insulating layer Z1 is provided between almost the entire lower surface of the conductive substrate 111 of the electrode 11 of the central solar cell 10 and approximately the right half of the upper surface of the electrode 63 of the bypass diode 60.

[0027] The solar cell module 2 configured in this manner can also achieve the same effects as the solar cell module 1. In addition to or instead of these, the bypass diode 50 is arranged across multiple (three) solar cell cells 10, 10, 10, so the area of ​​the bypass diode 50 can be more effectively increased. Also, the number of bypass diodes 50 required can be reduced, leading to cost reduction. Furthermore, since the insulating layer Z1 is interposed between the central solar cell 10 of the solar cell cells 10, 10, 10 and the bypass diode 50, short circuits between them can be more sufficiently suppressed, further contributing to improved reliability of the solar cell module 2.

[0028] Third Embodiment Figure 5 shows (A) a schematic side view and (B) a schematic plan (bottom) view illustrating an example of the configuration of a solar cell module according to a third embodiment of the present disclosure. The solar cell module 3 has the same configuration as the solar cell module 1, except that it includes a bypass diode 50' instead of the bypass diode 50. Here, the bypass diode 50' has substantially the same layered structure as the bypass diode 50, but is installed differently from the bypass diode 50. More specifically, as shown in Figure 5, the bypass diode 50' does not have the notch C formed in the bypass diode 50, and is joined to the solar cell cells 10, 10 such that the layered order of the electrode 51, the diode element layer 52, and the electrode 53 is reversed from that of the bypass diode 50.

[0029] Furthermore, in the solar cell module 3, similarly to the solar cell module 1, solar cells 10, 10 are connected in series via the conductive adhesive layer B1 to form a set of strings. Furthermore, in the solar cell module 3, a bypass diode 50' is connected in parallel to a set of strings including the solar cells 10, 10 via conductive adhesive layers B3, B4 and a conductive bridging member B5 to form a set of parallel circuits. More specifically, the right end portion of the lower surface of the conductive substrate 111 of the electrode 11 of the left solar cell 10 is connected to the left end portion of the upper surface of the electrode 53 of the bypass diode 50' by the conductive bridging member B5 via the conductive adhesive layer B4. Furthermore, substantially the entire lower surface of the conductive substrate 111 of the electrode 11 of the right solar cell 10 and the entire lower surface of the conductive substrate 511 of the electrode 51 of the bypass diode 50' are joined by the conductive adhesive layer B3 so as to overlap each other.

[0030] As described above, in the solar cell module 3, similarly to the solar cell module 1, the solar cells 10 are connected along their short sides (vertical direction) so that portions of each are stacked in order. The bypass diode 50' extends longitudinally across the solar cells 10, and is further arranged adjacent to the left-hand solar cell 10 of the solar cells 10 and overlaps with the solar cell 10 in the stacking direction of the solar cells 10. The solar cells 10 and the bypass diode 50' are insulated from each other by an air layer or an appropriate insulating layer, except at the electrical contact points.

[0031] The solar cell module 3 configured in this manner can also achieve the same effects as the solar cell module 1. In addition to or instead of these, the bypass diode 50' is disposed adjacent to the left solar cell 10 of the solar cells 10, 10, which is advantageous from the viewpoint of further thinning the solar cell module 3. Furthermore, the bypass diode 50' is connected to the solar cell 10 on its left side by the conductive bridging member B5, which allows for easy joining of the two, and furthermore, there is no need to provide the notch C in the bypass diode 50', which can further reduce manufacturing costs.

[0032] 6A and 6B are a schematic side view and a schematic plan (bottom) view, respectively, showing an example of the configuration of a solar cell module according to a fourth embodiment of the present disclosure. The solar cell module 4 has the same configuration as the solar cell module 2, except that it includes a bypass diode 60' instead of the bypass diode 60. The bypass diode 60' has a layered structure substantially identical to that of the bypass diode 60, but is installed differently from the bypass diode 60. More specifically, as shown in FIG. 6 , the bypass diode 60' does not have the notch C formed in the bypass diode 60, and is joined to the solar cell cells 10, 10, 10 such that the layered order of the electrode 61, the diode element layer 62, and the electrode 63 is reversed from that of the bypass diode 60.

[0033] Furthermore, in solar cell module 4, similarly to solar cell module 2, solar cells 10, 10, 10 are connected in series via conductive adhesive layer B1 to form a set of strings. Furthermore, in solar cell module 4, a bypass diode 60' is connected in parallel to a set of strings including solar cells 10, 10, 10 via conductive adhesive layers B3, B4 and a conductive bridging member B5 to form a set of parallel circuits. More specifically, the right end portion of the lower surface of the conductive substrate 111 of electrode 11 in the left solar cell 10 is connected to the left end portion of the upper surface of electrode 63 in bypass diode 60' via conductive adhesive layer B4 and conductive bridging member B5. Furthermore, substantially the entire lower surface of the conductive substrate 111 of electrode 11 in the right solar cell 10 and the right half of the lower surface of the conductive substrate of electrode 61 in bypass diode 60' are joined by conductive adhesive layer B3 so as to overlap each other.

[0034] As described above, in the solar cell module 4, similarly to the solar cell module 2, the solar cells 10 are connected along their short sides (vertical direction) so that portions of each are stacked in order. The bypass diode 60' is disposed so as to extend longitudinally across the solar cells 10, adjacent to the left-hand solar cell 10 among the solar cells 10, and overlapping with the solar cells 10 along the stacking direction. The solar cells 10 and the bypass diode 60' are insulated from each other by an air layer or an appropriate insulating layer, except for electrical contacts. For example, an insulating layer Z1 is provided between substantially the entire lower surface of the conductive substrate 111 of the electrode 11 of the central solar cell 10 and substantially the left half of the lower surface of the electrode 61 of the bypass diode 60'.

[0035] The solar cell module 4 configured in this manner can also achieve the same effects as the solar cell module 2. In addition to or instead of these, the bypass diode 60' is arranged across multiple (three) solar cell cells 10, 10, 10, so the area of ​​the bypass diode 60' can be more effectively increased. The required number of bypass diodes 50 can be reduced, leading to cost reduction. Furthermore, the insulating layer Z1 is interposed between the central solar cell 10 of the solar cell cells 10, 10, 10 and the bypass diode 60', which further suppresses short circuits between them, further contributing to improved reliability of the solar cell module 4.

[0036] Fifth Embodiment Figures 7 to 9 are schematic plan (bottom) views showing several examples of the configuration of a solar cell module according to a fifth embodiment of the present disclosure. Figure 6 is a re-illustration of the schematic plan (bottom) view of the solar cell module 1 shown in Figure 3(B), and the configuration of the solar cell module 5 is similar to that of the solar cell module 1 of the first embodiment. Solar cell modules 6 and 7 shown in Figures 7 and 8 have two and three bypass diodes 50, respectively. These solar cell modules 6 and 7 have the same stacked structure as the bypass diode 50 shown in Figure 6, except that the lengths of the short sides of the respective bypass diodes are, for example, at least half and at least one-third of those of the bypass diode 50 shown in Figure 6.

[0037] In any of these solar cell modules 5, 6, and 7, the multiple solar cell 10 are rectangular with short sides of substantially equal length, and one or more bypass diodes 50 are rectangular with long sides of substantially equal length. In this case, it is preferable that the length of the long side of each bypass diode 50 is not more than [X / S] times the length of the short side of each solar cell 10 (where [ ] indicates the Gauss symbol (integer portion)). Alternatively, it is also preferable that each bypass diode 50 is configured to straddle a maximum of [X / S]+1 solar cell 10. Here, "S" indicates the open-circuit voltage (V) of the solar cell 10 under standard test conditions, and "-X" indicates the allowable reverse voltage (V) of the solar cell 10.

[0038] More specifically, when the power generating element layer 12 of the solar cell 10 and the diode element layer 52 of the bypass diode 50 contain a chalcopyrite compound, it is more preferable that [X / S] is 4. Note that the solar cell modules 5, 6, and 7 shown in the figures illustrate a case where [X / S]=1.

[0039] Furthermore, in the solar cell modules 5, 6, and 7, when the allowable current density of the solar cell 10 is [n] times (here again, [ ] indicates the Gauss symbol (integer part)) the short-circuit current density generated under standard test conditions, it is preferable that the total area of ​​one or more bypass diodes 50 forming part of a set of parallel circuits is 1 / [n] or more of the area of ​​one solar cell 10. More specifically, when the power generation element layer 12 of the solar cell 10 and the diode element layer 52 of the bypass diode 50 contain a chalcopyrite compound, it is more preferable that [n] is 11. Note that in the solar cell modules 5, 6, and 7 shown in the figures, a case where [n] is approximately 5 or 6 is exemplified.

[0040] Furthermore, in the solar cell modules 5, 6, and 7, when there are k bypass diodes 50, it is preferable that the bypass diodes 50 are arranged in parallel so as to extend along odd-numbered imaginary lines that are perpendicular to the 2k-sector of the long side of the solar cell 10.

[0041] For example, in the case of solar cell module 5, there is one bypass diode 50, so there is one perpendicular bisector (k=1) of the long side of solar cell 10 (virtual line E51), and the bypass diode 50 extends along this virtual line E51 ( FIG. 6 ). In the case of solar cell module 6, there are two bypass diodes 50, so there are three perpendicular quadrants (k=2) of the long side of solar cell 10 (virtual lines E61 to E63), and the bypass diodes 50 are juxtaposed so as to extend along the odd-numbered virtual lines E61 and E63. In the case of solar cell module 7, there are three bypass diodes 50, so there are five perpendicular sextants (k=3) of the long side of solar cell 10 (virtual lines E71 to E75), and the bypass diodes 50 are juxtaposed so as to extend along the odd-numbered virtual lines E71, E73, and E75.

[0042] The solar cell modules 5, 6, and 7 configured in this manner can also achieve the same effects as the solar cell modules 1, 3, etc. In addition to or instead of these, the total area of ​​one or more bypass diodes 50 forming part of a set of parallel circuits can be configured to be 1 / [n] or more of the area of ​​one solar cell 10, and in particular, by setting [n] = 11 when the power generation element layer 12 and the diode element layer 52 contain a chalcopyrite compound, the current density of the bypass diode 50 during operation can be effectively kept within an allowable range. As a result, malfunctions of the bypass diode 50 can be more reliably prevented, further contributing to improved reliability of the solar cell modules 5, 6, and 7.

[0043] Furthermore, by configuring the length of the long side of the bypass diode 50 to be [X / S] times or less the length of the short side of the solar cell 10, or by configuring the bypass diode 50 to span a maximum of [X / S]+1 solar cell 10, and particularly by setting [X / S]=4 when the power generation element layer 12 and the diode element layer 52 contain a chalcopyrite compound, it is possible to minimize the required number of bypass diodes 50 and reduce costs, while ensuring sufficient reverse voltage resistance.

[0044] Furthermore, when there are k (k≧1) bypass diodes 50, the bypass diodes 50 can be arranged in parallel so as to extend along odd-numbered imaginary lines that divide the long sides of the solar cell 10 into 2k equal parts perpendicular to the long sides, thereby shortening the length of the short sides of each bypass diode 50 and reducing the width. This further alleviates current concentration in the bypass diodes 50, further suppressing heat generation and significantly improving reliability.

[0045] Reference Example 1 First, ten solar cells 10 having the structure shown in FIG. 1 in which the power generation element layer 12 contains a chalcopyrite compound were prepared as test specimens S1 to S10. The open-circuit voltage S (standard specification value) of these test specimens S1 to S10 was 0.6 (V), and the short-circuit current density (standard specification value) was 35 mA / cm. ２ Next, the allowable reverse voltage -X (V) representing the reverse voltage resistance when the prepared solar cell 10 specimens S1 to S10 were used as a bypass diode 50 having the structure shown in FIG. 2 in which the diode element layer 52 contains a chalcopyrite compound was measured. The obtained measurement results and the calculated [X / S] are summarized in Table 1. As a result, taking into account the variability among the specimens and including the standard deviation from the perspective of safety design, the allowable reverse voltage -X was the average value plus twice the standard deviation (2σ) = -2.6 (V). From this, it was confirmed that when the power generation element layer 12 of the solar cell 10 and the diode element layer 52 of the bypass diode 50 contain a chalcopyrite compound, [X / S] = [-2.6 / 0.6] = 4 (the integer part) is preferable.

[0046]

[0047] (Reference Example 2) The allowable current density (mA / cm ) of the solar cell 10 specimens S1 to S10 used in Reference Example 1 was measured. ２ ) was measured. The measurement results and the calculated [n] (allowable current density / integer part of short-circuit current density) are summarized in Table 2. As a result, taking into consideration the variability among the test specimens and including the standard deviation from the viewpoint of safety design, the average value of the allowable current density - twice the standard deviation (2σ) = 388 (mA / cm ２) and it has been confirmed that, when the power generating element layer 12 of the solar cell 10 and the diode element layer 52 of the bypass diode 50 contain a chalcopyrite compound, [n] = [388 / 35] = 11 (the integer part), that is, it is preferable that the total area of ​​one or more bypass diodes 50 forming part of one parallel circuit be 1 / 11 or more of the area of ​​one solar cell 10.

[0048]

[0049] The above-described embodiments are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. Furthermore, the elements included in each embodiment, as well as their arrangement, materials, conditions, shapes, dimensions, sizes, scales, and the like, are not limited to those illustrated or shown, unless otherwise specified, and may be modified as appropriate within the scope of the present disclosure. Furthermore, the configurations of each embodiment can be combined with each other. For example, the solar cell modules 1 to 7 may include layers other than those described above, or may include multiple layers of each of the above-described layers. Furthermore, the layers constituting the solar cell 10 and the bypass diode 50 may contain various additives, such as binders and surfactants, in addition to the main constituent materials described above. Furthermore, the p-type hole transport layer 121 and grid electrode 132 of the solar cell 10 may be omitted, and the light absorption layer 122 may have two or more layers. Furthermore, the bypass diodes 50, 50', 60, and 60' may also be pn junction diodes, p-i junction diodes, in junction diodes, p-i junction diodes, Schottky barrier diodes, and the like. In addition, the uses of the solar cell module according to the present disclosure are not particularly limited, and it can be preferably used as a power generation device by attaching it to the roof, window, or wall of a building, a mobile object, or an aircraft, etc. It can also be preferably used as an independent power source device for street lights, sensors, and digital signage, a mobile energy device, or a power generation device in space or the stratosphere.

[0050] 1 to 7... solar cell module, 10... solar cell, 11, 13, 51, 53, 61, 63... electrode, 12... power generation element layer, 50, 50', 60, 60'... bypass diode, 52, 62... diode element layer, 111, 511... conductive substrate, 112, 512... lower electrode layer, 121, 521... p-type hole transport layer, 122... light absorption layer, 123, 523... n-type electron transport layer, 131, 531... upper electrode layer, 132... grid electrode, 522... p-type semiconductor layer, 532... solid electrode, B1 to B3... conductive adhesive layer, B5... conductive bridging member, C... notch, E51, E61 to E63, E71 to E75... virtual line, Z1... insulating layer

Claims

1. A solar cell module comprising: a plurality of solar cells having a power generation element layer formed on a first conductive substrate; and one or more bypass diodes having a diode element layer formed on a second conductive substrate, wherein the power generation element layer of each of the plurality of solar cells is disposed on one side of the first conductive substrate, and each diode element layer of the one or more bypass diodes is disposed on the other side of the first conductive substrate, and the plurality of solar cells are connected in series to form a set of strings, and the one or more bypass diodes are connected in parallel to form a set of parallel circuits.

2. The solar cell module according to claim 1, wherein the plurality of solar cells are connected so that a portion of each solar cell is stacked in order.

3. The solar cell module according to claim 1, wherein each of the one or more bypass diodes is disposed across at least two of the solar cell cells.

4. The solar cell module according to claim 2, wherein the one or more bypass diodes are arranged so that each bypass diode overlaps along a stacking direction of the plurality of solar cells.

5. The solar cell module according to claim 2, wherein said one or more bypass diodes are positioned such that each bypass diode is adjacent to at least one of said plurality of solar cells.

6. The solar cell module according to claim 1, wherein the one or more bypass diodes have a notch formed in the diode element layer, and each bypass diode is connected to at least one of the plurality of solar cell cells at the notch.

7. The solar cell module according to claim 1, wherein each of said one or more bypass diodes is connected to at least one of said plurality of solar cells by a conductive bridging member.

8. The solar cell module according to claim 1, wherein the power generating element layer and the diode element layer contain the same material or materials of the same type.

9. The solar cell module according to claim 8, wherein when the allowable current density of the solar cell is [n] times the short-circuit current density generated under standard test conditions, the total area of ​​the one or more bypass diodes forming a part of the set of parallel circuits is 1 / [n] or more of the area of ​​one of the solar cell.

10. The solar cell module according to claim 9, wherein the power generating element layer and the diode element layer contain a chalcopyrite compound, and [n]=11.

11. The solar cell module as described in claim 8, wherein said plurality of solar cells are rectangular in shape with short sides of substantially equal length, and said one or more bypass diodes are rectangular in shape with long sides of substantially equal length, and when the open circuit voltage of said solar cell under standard test conditions is S (V) and the allowable reverse voltage of said solar cell is -X (V), the length of the long side of said bypass diode is not more than [X / S] times the length of the short side of said solar cell.

12. The solar cell module as described in claim 8, wherein the plurality of solar cells are rectangular in shape with short sides of substantially equal length, and the one or more bypass diodes are rectangular in shape with long sides of substantially equal length, and when an open circuit voltage of the solar cell under standard test conditions is S (V) and an allowable reverse voltage of the solar cell is -X (V), the bypass diode is provided across a maximum of [X / S] + 1 of the solar cell.

13. The solar cell module according to claim 11, wherein the power generating element layer and the diode element layer contain a chalcopyrite compound, and [X / S]=4.

14. The solar cell module as described in claim 1, wherein the plurality of solar cells are rectangular in shape with short sides of substantially equal length, and the one or more bypass diodes are rectangular in shape with long sides of substantially equal length, and when the number of the one or more bypass diodes is k (k≧1), the one or more bypass diodes are juxtaposed so as to extend along odd-numbered imaginary lines that are perpendicular to the 2k-sector of the long sides of the solar cell.

15. The solar cell module according to claim 1, wherein the solar cell and the bypass diode are insulated from each other except at electrical contacts.

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