Solar cell module

Abstract

To suppress the reduction in power generation area or the current concentration on a bypass diode, reduce the manufacturing cost and material cost sufficiently, and deal with the generalization and divergence of the device structure and applications.SOLUTION: A solar cell module includes a plurality of solar cells including a power generation layer on a first conductive substrate, and one or more bypass diodes including a diode element layer on a second conductive substrate. Each power generation element layer is disposed on one surface side of the first conductive substrate. Each diode element layer is disposed on the other side of the first conductive substrate. In a pair of strings formed by serial connection of the solar cells, one or more bypass diodes are connected in parallel to one or more solar cells, so that a pair of parallel circuits are formed. When the allowable current density of the solar cell is [n] times the short-circuit current density generated under a standard test condition, the total area of the one or more bypass diodes is 1 / [n] or more of the area of the one solar cell.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Generally, when a part of a string in which a plurality of solar cells are connected in series is covered with a shadow, such as on a wall or in-vehicle, the power generation of that part stops and the current is interrupted. If no measures are taken, the power generation of the entire string will stop. In addition, the resistance of the part covered with the shadow increases, and there is a risk of problems such as failures due to local heat generation. To prevent such adverse effects, it is necessary to incorporate bypass diodes for bypassing the generated current for each solar cell or string. In particular, in a solar cell module installed in an environment that is largely affected by shadows, it is desirable to incorporate a relatively large number of bypass diodes.

[0003] To meet such demands, for example, Patent Document 1 describes a solar cell module including a solar cell formed on a transparent substrate on the light-receiving surface side and a bypass diode formed thereon. With such a configuration, it is intended to suppress heat generation due to current concentration by relatively increasing the area of the bypass diode while preventing a decrease in the light-receiving area of the solar cell.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described conventional solar cell module, since a bypass diode is laminated and formed on the solar cell, the manufacturing process cannot be sufficiently simplified to provide a large-area bypass diode, and the manufacturing cost and material cost cannot be sufficiently reduced. Further, in the configuration of the above-described conventional solar cell module, an opaque substrate cannot be used to secure a light-receiving surface, and thus there is also a problem that it cannot sufficiently cope with diversification and generalization of device structures and applications.

[0006] Therefore, the present disclosure has been made in view of such circumstances, and by realizing a large area of the bypass diode without impairing the light-receiving area of the solar cell, it is possible to sufficiently reduce the manufacturing cost and the material cost while eliminating a decrease in the power generation area and current concentration on the bypass diode. Another object of the present disclosure is to provide a solar cell module that can sufficiently cope with diversification and generalization of device structures and applications.

Means for Solving the Problems

[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. Each power generation element layer in the plurality of solar cells is disposed on one side of the first conductive substrate, and each diode element layer in the one or more bypass diodes is disposed on the other side of the first conductive substrate. Further, one or more bypass diodes are connected in parallel to a set of strings formed by connecting the plurality of solar cells in series, thereby forming a set of parallel circuits.

[0008] In a solar cell module having such a configuration, power generation is performed by receiving light from one surface side of the first conductive substrate provided with the power generation element layer of the solar cell. Further, since the diode element of the bypass diode is disposed on the other surface side (non-light receiving surface side) of the first conductive substrate, the incident light to the solar cell is not blocked by the bypass diode, and a decrease in the light receiving area is suppressed. Further, with such a structure, it becomes easy to increase the area of the bypass diode, and current concentration in the bypass diode can be effectively eliminated. As a result, light energy can be effectively utilized even in an environment that is easily affected by shadows such as building wall surfaces and in-vehicle applications. Furthermore, since it is not necessary to stack a bypass diode on the solar cell, both the manufacturing cost and the material cost can be sufficiently reduced. In addition, with such a structure, an opaque substrate can be used as the first conductive substrate and the second conductive substrate, which contributes to diversification and generalization of the device structure and applications.

Brief Description of the Drawings

[0009]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Embodiments for Carrying Out the Invention

[0010] <Definition of Terms, etc.> Hereinafter, with reference to the accompanying drawings, a solar cell module according to a preferred embodiment of the present disclosure will be described. In this document, for the sake of convenience, in both the solar cell and the bypass diode in the solar cell module, the direction in which each layer is laminated with respect to the substrate is referred to as upward, the opposite direction is referred to as downward, and the coordinate axis direction is up and down (it may be different from the up and down in the drawing). Also, the left side as shown in the drawing is simply referred to as "left side" or "left", and the right side as shown in the drawing is simply referred to as "right side" or "right". Furthermore, in this document, when each layer or the semiconductor contained in each layer is expressed by the name of a certain compound, it includes not only the pure compound itself but also a compound doped with trace elements, chemical species, etc. within the range where the characteristics of the compound are not lost. Also, in this document, since the elements in each layer can exist in different oxidation states, all oxidation states are referred to by the name of the element unless specifically stated otherwise. For example, the "hydrogen element" and its chemical symbol "H" can mean a hydrogen atom, a hydrogen ion, a hydride ion, a hydrogen radical, hydrogen in a compound state, and hydrogen in a single state.

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

[0012] (Electrode 11) 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. The thickness thereof is preferably about 10 to 500 μm, for example. Also, the lower electrode layer 112 is not particularly limited, and for example, a metal conductive layer made of Mo, Cr, Ti, etc., a conductive inorganic compound conductive layer other than metal, a conductive organic compound conductive layer, etc. can be used. The thickness of the lower electrode layer 112 is also not particularly limited, and is preferably about 200 to 800 nm, for example.

[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 laminated in 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 about 20 to 100 nm, for example. Also, the material for forming the light absorption layer 122 is not particularly limited, and examples thereof include perovskite compounds such as (Cs,FA)PbI 3 and chalcopyrite compounds such as Cu(In,Ga)(Se,S) 2 and kesterite compounds such as Cu 2 ZnSnS 4 These may be used alone or in combination of two or more. The thickness of the light absorption layer 122 is also not particularly limited, and is preferably about 1 to 5 μm, for example. Further, the material for forming the n-type electron transport layer 123 is not particularly limited, and examples thereof include Zn(O,S,OH)x, CdS, In 2 S 3, examples include ZnTiOx, etc. These may be used alone or in combination of two or more. The thickness of the n-type electron transport layer 123 is also not particularly limited, and for example, it is preferably about 20 to 150 nm.

[0014] (Electrode 13) The electrode 13 is composed of an upper electrode layer 131 and a grid electrode 132 laminated in 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 include transparent electrode layers such as ITO, IOH, FTO, ZnO:B, and ZnO:Al. The thickness of the upper electrode layer 131 is not particularly limited, and for example, it is preferably about 0.1 to 2 μm. Also, the grid electrode 132 is not particularly limited, and for example, a metal conductive layer made of Mo, Cr, Ag, etc., a conductive inorganic compound conductive layer other than metal, a conductive organic compound conductive layer, etc. can be used. The thickness of the grid electrode 132 is also not particularly limited, and for example, it is preferably about 5 to 50 μm.

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

[0016] (Electrode 51, Diode element layer 52, Electrode 53) The electrode 51 is composed of a conductive substrate 511 (second conductive substrate) laminated in sequence on the lower electrode layer 512 of the electrode 51 and the lower electrode layer 512 formed thereon, similar to the electrode 11 described above. As these conductive substrate 511 and lower electrode layer 512, those configured similarly to the conductive substrate 111 and lower electrode layer 112 can be used respectively. Also, 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 sequence on the lower electrode layer 512 of the electrode 51, similar to the power generation element layer 12 described above. As these p-type hole transport layer 521, p-type semiconductor layer 522, and n-type electron transport layer 523, those configured similarly to the p-type hole transport layer 121, light absorption layer 122, and n-type electron transport layer 123 can be used respectively. Further, the electrode 53 is composed of an upper electrode layer 531 and a solid electrode 532 laminated in sequence on the n-type electron transport layer 523 of the diode element layer 52, similar to the electrode 13 described above. As the constituent materials of these upper electrode layer 531 and solid electrode 532, those of the same type as the upper electrode layer 131 and grid electrode 132 can be used respectively. As such, as the bypass diode 50, a device having a configuration substantially equivalent to that of the solar cell 10 can be used, and the power generation element layer 12 and the diode element layer 52 can include the same material or similar materials. Furthermore, in the bypass diode 50, a notch C is formed at the right end portions of the diode element layer 52 and the electrode 53, and the upper right end surface of the lower electrode layer 512 of the electrode 51 is exposed. Note that the method for forming the notch C is not particularly limited, and for example, scribing, etching, patterning, etc. can be appropriately selected and applied.

[0017] Next, FIG. 3 is a (A) schematic side view and (B) schematic plan (bottom) view showing an example of the configuration of the first embodiment by the solar cell module of the present disclosure. The solar cell module 1 includes two rectangular solar cell cells 10, 10 and one rectangular bypass diode 50. In the solar cell module 1, the solar cell cells 10, 10 are connected in series via a conductive adhesive layer B1 to form a set of strings. More specifically, the upper right end portion of the grid electrode 132 of the electrode 13 in the left solar cell cell 10 and the lower left end portion of the conductive substrate 111 of the electrode 11 in the right solar cell cell 10 are overlapped and joined by the conductive adhesive layer B1.

[0018] Further, in the solar cell module 1, a bypass diode 50 is connected in parallel to a set of strings including the solar cell cells 10, 10 via conductive adhesive layers B2, B3 to form a set of parallel circuits. More specifically, the substantially entire lower surface of the conductive substrate 111 of the electrode 11 in the right solar cell cell 10 and the entire upper surface of the electrode 53 in the bypass diode 50 are overlapped and joined by the conductive adhesive layer B2. Also, the lower left end portion of the conductive substrate 111 of the electrode 11 in the right solar cell cell 10 and the upper right end portion of the lower electrode layer 512 of the electrode 51 exposed by the notch C in the bypass diode 50 are overlapped and joined by the conductive adhesive layer B3.

[0019] As described above, in the solar cell module 1, the solar cells 10, 10 are connected along the short sides (the vertical direction in Fig. 3(A)) so as to be stacked in order in respective parts thereof. Further, the bypass diodes 50 are arranged so as to extend in the longitudinal direction across the solar cells 10, 10 and overlap along the stacking direction of the solar cells 10, 10. Still further, in other words, the respective power generation element layers 12, 12 of the solar cells 10, 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 surface side) of the conductive substrate 111. Additionally, the portions where the conductive adhesive layer B1 is provided serve as the electrical contacts of the solar cells 10, 10, and the portions where the conductive adhesive layers B2, B3 are provided serve as the electrical contacts between the solar cells 10, 10 and the bypass diodes 50. Note that the solar cells 10, 10 and the bypass diodes 50 are insulated by an air layer or an appropriate insulating layer except at the electrical contacts.

[0020] According to the solar cell module 1 configured as described above, power generation is performed by receiving light from one side of the conductive substrate 111 (first conductive substrate) provided with the power generation element layer 12 of the solar cell 10. Further, since 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, it is possible to suppress a decrease in the light receiving area without blocking the incident light to the solar cell 10 by the bypass diode 50. Also, with such a structure, it becomes easy to increase the area of the bypass diode 50, and current concentration in the bypass diode 50 can be eliminated. As a result, light energy can be effectively utilized even in an environment that is easily affected by shadows such as building wall surfaces and in-vehicle applications. Furthermore, it is not necessary to stack and form the bypass diode 50 on the solar cell 10, and moreover, the solar cells 10, 10 and the bypass diode 50 can be easily joined by the conductive adhesive layers B1 to B3. Therefore, it is possible to sufficiently reduce both the manufacturing cost and the material cost. In addition, with such a structure, an opaque substrate can be used as the conductive substrate 111 and the conductive substrate 511, which further contributes to diversification and generalization of the device structure and applications.

[0021] Also, both the solar cell 10 and the bypass diode 50 of the solar cell module 1 can be configured as a laminated structure of materials that are easily thinned, which is useful from the viewpoints of thinning and flexibility of the solar cell module 1. Further, since a part of each of the solar cells 10, 10 are connected so as to be laminated in order to form a string, further thinning and flexibility of the solar cell module 1 can be achieved. Additionally, since the bypass diode 50 is disposed across a plurality (two) of the solar cells 10, 10, enlargement of the area of the bypass diode 50 can be effectively achieved. Moreover, since the bypass diode 50 is disposed so as to overlap along the stacking direction of the solar cells 10, 10, it can also contribute to miniaturization of the solar cell module 1.

[0022] Further, 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 cells 10, 10 at the notch C. Thereby, the joining of the solar cell 10 and the bypass diode 50 can be further simplified, contributing to further cost reduction. Further, since both the power generation element layer 12 and the diode element layer 52 include the same material or the same type of material such as a chalcopyrite compound, etc., the solar cell 10 and the bypass diode 50 can be used in common, and further reduction of manufacturing cost and management cost can be realized. In addition, since the solar cell 10 and the bypass diode 50 are insulated from each other except at the electrical contacts, a short circuit between the two can be sufficiently suppressed, contributing to improvement of the reliability of the solar cell module 1.

[0023] <Second Embodiment> FIG. 4 is a (A) schematic side view and (B) schematic plan (bottom) view showing an example of the configuration of the second embodiment by the solar cell module of the present disclosure. The solar cell module 2 is configured in the same manner as the solar cell module 1 except that it includes three solar cells 10, 10, 10 and is provided with a bypass diode 60 instead of the bypass diode 50. Here, the bypass diode 60 has electrodes 61, 63 and a diode element layer 62 provided therebetween. These electrodes 61, the diode element layer 62, and the electrode 63 can be configured in the same manner as the electrode 51, the diode element layer 52, and the electrode 53 of the 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 set of strings. More specifically, the upper right end portion of the grid electrode 132 of the electrode 13 in the left solar cell 10 and the lower left end portion of the conductive substrate 111 of the electrode 11 in the central solar cell 10 overlap each other and are joined by the conductive adhesive layer B1. Similarly, the upper right end portion of the grid electrode 132 of the electrode 13 in the central solar cell 10 and the lower left end portion of the conductive substrate 111 of the electrode 11 in the right solar cell 10 overlap each other and are joined by the conductive adhesive layer B1.

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

[0026] As described above, in the solar cell module 2, the solar cells 10, 10, 10 are connected along the short sides (the vertical direction in Fig. 4(A)) so as to be laminated in order at respective parts. Further, the bypass diode 60 is a member longer than the bypass diode 50, and is arranged so as to extend in the longitudinal direction across the solar cells 10, 10, 10 and to overlap along the lamination direction of the solar cells 10, 10, 10. Furthermore, in other words, the respective power generation element layers 12, 12, 12 of the solar cells 10, 10, 10 are arranged on one surface side of the conductive substrate 111, and the diode element layer 62 of the bypass diode 60 is arranged on the other surface side (non-light receiving surface side) of the conductive substrate 111. Additionally, the portions where the conductive adhesive layers B1, B1 are provided are the electrical contacts of the solar cells 10, 10, 10, and the portions where the conductive adhesive layers B2, B3 are provided are the electrical contacts between the solar cells 10, 10 and the bypass diode 60. Note that the solar cells 10, 10, 10 and the bypass diode 50 are insulated by an air layer or an appropriate insulating layer except at the 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 in the central solar cell 10 and substantially the right half of the upper surface of the electrode 63 in the bypass diode 60.

[0027] Also in the solar cell module 2 configured as described above, the same operational effects as those of the solar cell module 1 can be obtained. In addition to or instead of these, since the bypass diode 50 is arranged across a plurality (three) of the solar cells 10, 10, 10, the area of the bypass diode 50 can be further effectively increased. Also, the required number of bypass diodes 50 can be reduced, leading to cost reduction. Further, since an insulating layer Z1 is interposed between the central solar cell 10 among the solar cells 10, 10, 10 and the bypass diode 50, a short circuit between the two can be more sufficiently suppressed, further contributing to improving the reliability of the solar cell module 2.

[0028] <Embodiment 3> FIG. 5 is a (A) schematic side view and (B) schematic plan (bottom) view showing an example of the configuration of the third embodiment by the solar cell module of the present disclosure. The solar cell module 3 is configured in the same manner 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 a laminated structure substantially equivalent to that of the bypass diode 50, but the installation state is different from that of the bypass diode 50. More specifically, as shown in FIG. 5, the bypass diode 50' does not have the notch C formed in the bypass diode 50, and the lamination order of the electrode 51, the diode element layer 52, and the electrode 53 is reversed from that of the bypass diode 50, and it is joined to the solar cells 10, 10.

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

[0030] As described above, in the solar cell module 3 as well, like the solar cell module 1, the solar cells 10, 10 are connected along the short sides (vertical direction) such that they are sequentially stacked in respective parts. Further, the bypass diode 50' extends in the longitudinal direction across the solar cells 10, 10, and is arranged so as to be adjacent to the left solar cell 10 among the solar cells 10, 10 and to overlap along the stacking direction of the solar cells 10, 10. Note that the solar cells 10, 10 and the bypass diode 50' are insulated from each other by an air layer or an appropriate insulating layer except at the electrical contacts.

[0031] Also in the solar cell module 3 configured as described above, the same operational effects as those of the solar cell module 1 can be obtained. Further, in addition to or instead of those, since the bypass diode 50' is arranged to be adjacent to the left solar cell 10 among the solar cells 10, 10, it is advantageous from the viewpoint of further thinning of the solar cell module 3. Further, since the bypass diode 50' is connected to the left solar cell 10 by the conductive crosslinking member B5, the joining of the two can be easily performed, and furthermore, since it is not necessary to provide the notch C in the bypass diode 50', further reduction of the manufacturing cost can be achieved.

[0032] <Fourth Embodiment> FIG. 6 is a (A) schematic side view and (B) schematic plan (bottom) view showing an example of the configuration of the fourth embodiment of the solar cell module of the present disclosure. The solar cell module 4 is configured in the same manner as the solar cell module 2 except that it includes a bypass diode 60' instead of the bypass diode 60. Here, the bypass diode 60' has a stacking structure substantially equivalent to that of the bypass diode 60, but is installed in a different state 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 cells 10, 10, 10 such that the stacking 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 the solar cell module 4 as well, similar to the solar cell module 2, the solar cells 10, 10, 10 are connected in series via the conductive adhesive layer B1 to form a set of strings. Still further, in the solar cell module 4, a bypass diode 60' is connected in parallel to a set of strings including the solar cells 10, 10, 10 by means of the conductive adhesive layers B3, B4 and the conductive bridging member B5 to form a set of parallel circuits. More specifically, the lower right end of the conductive substrate 111 of the electrode 11 in the left solar cell 10 is connected to the upper left end of the electrode 63 in the bypass diode 60' by means of the conductive bridging member B5 via the conductive adhesive layer B4. Also, the substantially entire lower surface of the conductive substrate 111 of the electrode 11 in the right solar cell 10 and the right half of the lower surface of the conductive substrate of the electrode 61 in the bypass diode 60' are joined by means of the conductive adhesive layer B3 so as to overlap.

[0034] As described above, in the solar cell module 4 as well, similar to the solar cell module 2, the solar cells 10, 10, 10 are connected along the short sides (vertical direction) such that they are sequentially stacked in respective parts. Also, the bypass diode 60' is arranged so as to extend in the longitudinal direction across the solar cells 10, 10, 10, adjacent to the left solar cell 10 among the solar cells 10, 10, 10, and overlap along the stacking direction of the solar cells 10, 10, 10. Note that the solar cells 10, 10, 10 and the bypass diode 60' are insulated by an air layer or an appropriate insulating layer other than at the electrical contacts. For example, an insulating layer Z1 is provided between the substantially entire lower surface of the conductive substrate 111 of the electrode 11 in the central solar cell 10 and the substantially left half of the lower surface of the electrode 61 in the bypass diode 60'.

[0035] Even in the solar cell module 4 configured as described above, the same operational effects as those of the solar cell module 2 can be obtained. Further, in addition to or instead of these, since the bypass diode 60' is arranged across a plurality (three) of solar cell units 10, 10, 10, the area of the bypass diode 60' can be further effectively increased. Also, the required number of bypass diodes 50 can be reduced, leading to cost reduction. Further, since an insulating layer Z1 is interposed between the central solar cell unit 10 and the bypass diode 60' among the solar cell units 10, 10, 10, a short circuit between the two can be more sufficiently suppressed, further contributing to the improvement in the reliability of the solar cell module 4.

[0036] <Fifth Embodiment> Figs. 7 to 9 are schematic plan (bottom) views showing a plurality of examples of the configuration of the fifth embodiment by the solar cell module of the present disclosure. Fig. 6 is a reproduction of the schematic plan (bottom) view of the solar cell module 1 shown in Fig. 3(B), and the configuration of the solar cell module 5 is the same as that of the solar cell module 1 of the first embodiment. Also, the solar cell modules 6, 7 shown in Figs. 7 and 8 each have two and three bypass diodes 50, respectively. In these solar cell modules 6, 7, they have the same laminated structure as the bypass diode 50 in Fig. 6, except that the length of each short side is, for example, 1 / 2 or more, and 1 / 3 or more of that of the bypass diode 50 shown in Fig. 6.

[0037] In any of these solar cell modules 5, 6, and 7, a plurality of solar cells 10 form a rectangular shape with substantially equal short side lengths, and one or more bypass diodes 50 form a rectangular shape with substantially equal long side lengths. 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 Gaussian symbol (integer part)). Alternatively, it is also preferable that each bypass diode 50 is configured to straddle a maximum of [X / S] + 1 solar cells 10. Here, "S" represents the open-circuit voltage (V) of the solar cell 10 under standard test conditions, and "-X" represents the allowable reverse voltage (V) of the solar cell 10.

[0038] 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 [X / S] is 4. In the illustrated solar cell modules 5, 6, and 7, the case where [X / S] = 1 is exemplified.

[0039] Also, in the solar cell modules 5, 6, and 7, when the allowable current density of the solar cell 10 is [n] times the short-circuit current density generated under standard test conditions (again, [ ] indicates the Gaussian symbol (integer part)), it is preferable that the total area of one or more bypass diodes 50 forming part of a set of parallel circuits is not less than 1 / [n] 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. In the illustrated solar cell modules 5, 6, and 7, the cases where [n] ≈ 5 or 6 are exemplified.

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

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

[0042] Even in the solar cell modules 5, 6, and 7 configured as described above, the same operational effects as those of the solar cell modules 1, 3, etc. can be obtained. In addition to or in place of these, the total area of one or more bypass diodes 50 forming part of a set of parallel circuits is configured to be 1 / [n] or more of the area of one solar cell 10. In particular, when the power generation element layer 12 and the diode element layer 52 contain a chalcopyrite compound, by setting [n] = 11, the current density during the operation of the bypass diode 50 can be effectively suppressed within an allowable range. As a result, malfunction of the bypass diode 50 can be more reliably prevented, and it can further contribute to improving the reliability of the solar cell modules 5, 6, and 7.

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

[0044] Furthermore, when there are k (k ≧ 1) bypass diodes 50, by juxtaposing the bypass diodes 50 along the odd-numbered virtual lines of the perpendicular 2k equal division lines of the long side of the solar cell 10, the length of the short side of each bypass diode 50 can be shortened and narrowed. As a result, the current concentration in the bypass diode 50 can be further alleviated, heat generation can be further suppressed, and the reliability can be further improved.

[0045] (Reference Example 1) Here, first, as test specimens S1 to S10, 10 solar cells 10 having the structure shown in Fig. 1 in which the power generation element layer 12 contains a chalcopyrite compound were prepared. The open-circuit voltage S (specification standard value) of these test specimens S1 to S10 was 0.6 (V), and the short-circuit current density (specification standard value) was 35 mA / cm 2 was. Next, the allowable reverse voltage -X (V), which is the reverse voltage resistance when the prepared test specimens S1 to S10 of the solar cell 10 are used as the 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, considering the variation among the test specimens, from the viewpoint of safety design, including the standard deviation, the average value of the allowable reverse voltage -X plus twice the standard deviation (2σ) = -2.6 (V). From this, 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 was confirmed that [X / S] = [-2.6 / 0.6] = 4 (integer part) is suitable.

[0046]

Table 1

[0047] (Reference Example 2) Regarding the test specimens S1 to S10 of the solar cell 10 used in Reference Example 1, the allowable current density (mA / cm 2) was measured. The obtained measurement results and the calculated [n] (the integer part of the allowable current density / short-circuit current density) are summarized in Table 2. As a result, considering the variation among the test specimens, from the viewpoint of safety design, including the standard deviation, the average value of the allowable current density - twice the standard deviation (2σ) = 388 (mA / cm 2 ) is obtained. From this, 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, [n] = [388 / 35] = 11 (the integer part), that is, it is confirmed that it is preferable that the total area of one or more bypass diodes 50 forming part of a set of parallel circuits is 1 / 11 or more of the area of one solar cell 10.

[0048]

Table 2

[0049] Each of the embodiments described above is for facilitating the understanding of the present disclosure and is not for limiting and interpreting the present disclosure. In addition, each element included in each embodiment, as well as its arrangement, material, conditions, shape, dimensional size, scale, etc., are not limited to those exemplified or illustrated unless otherwise explicitly stated, and can be appropriately changed within the scope of the gist of the present disclosure. Furthermore, it is also possible to combine the configurations of each embodiment with each other. For example, the solar cell modules 1 to 7 may include layers other than the layers described above, or may include a plurality of the layers described above. Also, each layer constituting the solar cell 10 and the bypass diode 50 may contain various additives such as a binder and a surfactant in addition to the main constituent materials described above. Furthermore, the p-type hole transport layer 121 and the grid electrode 132 of the solar cell 10 may not be provided, and two or more light absorption layers 122 may be provided. Still further, as the bypass diodes 50, 50', 60, 60', other pn junction diodes, pin junction diodes, in junction diodes, pi junction diodes, and Schottky barrier diodes, etc. can also be used. In addition, the use of the solar cell module according to the present disclosure is not particularly limited, and for example, it can be preferably used as a power generation device by being attached to the roofs, windows, and wall surfaces of buildings, moving bodies, and aircraft. Also, among others, it can also be preferably used as an independent power supply device for street lights, sensors, digital signage, mobile energy devices, and power generation devices in space or the stratosphere.

Description of Reference Numerals

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

Claims

1. a plurality of solar cells each having a power generating element layer formed on a first conductive substrate; one or more bypass diodes having a diode element layer formed on a second conductive substrate; Equipped with the power generating element layers of the plurality of solar cells are disposed on one surface side of the first conductive substrate, each diode element layer of the one or more bypass diodes is disposed on the other surface side of the first conductive substrate; In one string formed by connecting the plurality of solar cells in series, one or more of the solar cells are connected in parallel to the one or more bypass diodes to form a set of parallel circuits, 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. Solar cell module.

2. a plurality of solar cells each having a power generating element layer formed on a first conductive substrate; one or more bypass diodes having a diode element layer formed on a second conductive substrate; Equipped with the power generating element layers of the plurality of solar cells are disposed on one surface side of the first conductive substrate, each diode element layer of the one or more bypass diodes is disposed on the other surface side of the first conductive substrate; In one string formed by connecting the plurality of solar cells in series, one or more of the solar cells are connected in parallel to the one or more bypass diodes to form a set of parallel circuits, 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, When the open circuit voltage of the solar cell under standard test conditions is S (V) and the allowable reverse voltage of the solar cell is −X (V), the length of the long side of the bypass diode is equal to or less than [X / S] times the length of the short side of the solar cell. Solar cell module.

3. a plurality of solar cells each having a power generating element layer formed on a first conductive substrate; one or more bypass diodes having a diode element layer formed on a second conductive substrate; Equipped with the power generating element layers of the plurality of solar cells are disposed on one surface side of the first conductive substrate, each diode element layer of the one or more bypass diodes is disposed on the other surface side of the first conductive substrate; In one string formed by connecting the plurality of solar cells in series, one or more of the solar cells are connected in parallel to the one or more bypass diodes to form a set of parallel circuits, 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, 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 solar cells. Solar cell module.

4. The plurality of solar cells are connected so that a portion of each solar cell is stacked in order. The solar cell module according to any one of claims 1 to 3.

5. The one or more bypass diodes are each disposed across at least two of the solar cells. The solar cell module according to claim 1 or 2.

6. the one or more bypass diodes are arranged so that each bypass diode overlaps with the other in a stacking direction of the plurality of solar cells; The solar cell module according to claim 5.

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

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

9. the one or more bypass diodes are each connected to at least one of the plurality of solar cells by a conductive bridging member; The solar cell module according to claim 7.

10. the power generating element layer and the diode element layer contain a chalcopyrite compound; The solar cell module according to any one of claims 1 to 3.

11. [n]=11, The solar cell module according to claim 10 which recites claim 1.

12. [X / S]=4; The solar cell module according to claim 10 , which cites claim 2 or 3 .

13. 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, When the number of the one or more bypass diodes is k (k≧1), the one or more bypass diodes are arranged in parallel so as to extend along odd-numbered imaginary lines of a perpendicular 2k-equidistant line of the long side of the solar cell. The solar cell module according to any one of claims 1 to 3.

14. The solar cell and the bypass diode are insulated from each other except for the electrical contacts. The solar cell module according to any one of claims 1 to 3.

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