Solar cell module and manufacturing method of the solar cell module

Abstract

To provide: a solar cell module capable of suppressing the generation of fine wrinkles in a curved film substrate with respect to a curved plate-shaped solar cell module; and a manufacturing method of the solar cell module.SOLUTION: A curved plate-shaped solar cell module 1 includes a surface layer 2, a back surface layer 3, first and second solar cell units 4 and 5, and a sealing material 6. The first solar cell unit 4 includes a plurality of strip-shaped first cells 40, and each of the first cells 40 includes a flexible strip-shaped film base material 42 and a perovskite element 41, and is curved in accordance with the curved shape of the solar cell module 1, and a reinforcing part 42a having a higher bending rigidity than other portions of the film base material 42, is formed at an edge part along a longitudinal direction of the film base material 42.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a solar cell module and a method for manufacturing a solar cell module. [Background technology]

[0002] As an example of this type of technology, Patent Document 1 discloses a tandem solar cell module. This solar cell module includes a first protective member and a second protective member, both of which are light-transmitting. In the gap between these members, a first solar cell unit and a second solar cell unit are arranged, in that order from the first protective member side. The first solar cell unit has a plurality of strip-shaped first solar cell elements. These are arranged in parallel on the first protective member in the short-side direction of the first solar cell elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-102620 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a solar cell module has a curved shape, it is difficult to apply the first solar cell element (so-called power generation element) described in Patent Document 1 to the surface of the curved first protective member. Therefore, it is conceivable to arrange the power generation elements on a strip-shaped film substrate so that the cells are arranged in parallel in the short direction, and then curve the film substrate according to the curved shape of the solar cell module.

[0005] However, for example, when sunlight is irradiated onto a solar cell module, the temperature distribution of the solar cell module may not be uniform. This may cause localized stress in the film substrate due to differential elongation in the longitudinal direction of the film substrate caused by temperature changes, resulting in the formation of fine wrinkles in the film substrate. This phenomenon is particularly likely to occur when the film substrate is curved, which may result in a decrease in the performance of the solar cell module.

[0006] The present invention has been made in consideration of these points, and aims to provide a solar cell module that can suppress the occurrence of fine wrinkles in a curved film substrate for a curved, plate-shaped solar cell module, and a method for manufacturing the solar cell module. [Means for solving the problem]

[0007] In view of the above-mentioned problems, the solar cell module of the present invention is a curved, plate-shaped solar cell module comprising: a light-transmitting surface layer; a back layer; first and second solar cell units arranged between the surface layer and the back layer in this order from the surface layer side; and a sealing material that seals the first and second solar cell units; the first solar cell unit has a plurality of strip-shaped first cells that are arranged in parallel in the short direction of the first cells, and each of the first cells has a flexible strip-shaped film substrate and a first power generation element arranged on one surface of the film substrate along the longitudinal direction of the film substrate, and is curved according to the curved shape of the solar cell module; the second solar cell unit has a plurality of second power generation elements arranged along the longitudinal direction of the film substrate so as to face the other surface of each of the film substrate along the longitudinal direction of the first cells, and a reinforcing portion having higher bending rigidity than other portions of the film substrate is formed at an edge portion of the film substrate along the longitudinal direction.

[0008] In view of the above-mentioned problems, a manufacturing method of a solar cell module according to the present invention is a manufacturing method of a curved plate-shaped solar cell module, the solar cell module including first and second solar cell units, the first solar cell unit having a plurality of strip-shaped first cells, each of the first cells having a flexible strip-shaped film substrate and a first power generation element arranged on one surface of the film substrate along a longitudinal direction of the film substrate, the second solar cell unit having a plurality of second power generation elements, the manufacturing method including sandwiching a resin sealing sheet between a light-transmitting, curved front panel and a curved back panel. and a heat-pressing step of heat-pressing the laminate at a heating temperature equal to or higher than the softening point of the resin of the sealing sheet until the first and second solar cell units are sealed with the resin of the sealing sheet, wherein in the heat-pressing step, the first cells, each having a reinforcing portion formed on an edge along the longitudinal direction of the film substrate and having a higher bending rigidity than other portions of the film substrate, are arranged in parallel in the short direction of the first cells, and the second power generation elements are arranged along the longitudinal direction of the film substrate so as to face the other surface of each of the film substrates along the longitudinal direction of the first cells. [Effects of the Invention]

[0009] According to the present invention, it is possible to prevent fine wrinkles from occurring in the curved film substrate of a curved plate-shaped solar cell module. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view schematically showing a state in which a solar cell module according to an embodiment of the present invention is mounted on an existing roof substrate of a vehicle. [Figure 2] FIG. 1 is an exploded perspective view of a solar cell module according to an embodiment of the present invention. [Figure 3]3A is a cross-sectional view taken along line AA in Fig. 1. 3B is a cross-sectional view taken along line BB in Fig. 1. 3C is an enlarged view of the area surrounded by the dashed dotted line in Fig. 3B. 3D is an explanatory view schematically showing a method for manufacturing a solar cell module according to this embodiment. [Figure 4] 4A is a plan view schematically showing a state in which a solar cell module according to a modified example is mounted as part of a roof of a vehicle, and FIG. 4B is a cross-sectional view taken along CC in FIG. [Figure 5] 5A is a plan view schematically showing a solar cell module according to a modified example, in which a plurality of silicon crystal elements arranged in parallel in two rows are entirely contained in one second cell, and FIG. 5B is a cross-sectional view taken along line DD in FIG. 5A. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to Figures 1 to 5(B). Note that the embodiments described below are merely aspects of the present invention and do not limit the technical scope of the present invention.

[0012] <Configuration> FIG. 1 is a plan view schematically showing a solar cell module 1 according to this embodiment mounted on an existing roof substrate of a vehicle 7. The solar cell module 1 according to this embodiment is mounted on the roof substrate to form a roof 71 of the vehicle 7. The solar cell module 1 has a curved, plate-like shape. Therefore, it can be mounted on the roof substrate in accordance with the shape of the roof substrate of the vehicle 7, which is also curved. In the example shown in FIG. 1, the curvature of the roof substrate is greater in the vehicle length direction (the up-down direction in the orientation of FIG. 1) than in the vehicle width direction of the vehicle 7 (the left-right direction in the orientation of FIG. 1). Accordingly, the solar cell module 1 is shaped so that the roof 71 has a shape with a greater curvature in the vehicle length direction and is mounted on the roof substrate.

[0013] The solar cell module 1 has a tandem structure, and has a surface layer 2 made of translucent glass on the top layer of the roof 71 (i.e., the frontmost layer in the orientation of FIG. 1). When sunlight or other light is irradiated onto the solar cell module 1, the irradiated light passes through the surface layer 2 and reaches the inside of the solar cell module 1. This generates an electromotive force between the positive and negative electrodes of the solar cell module 1, and the generated electricity can be supplied to the vehicle 7.

[0014] The solar cell module 1 is thin and lightweight, and by taking advantage of these characteristics, the solar cell module 1 can be mounted on a variety of objects in addition to the roof substrate of the vehicle 7 illustrated in FIG.

[0015] Fig. 2 is an exploded perspective view of a solar cell module 1 according to this embodiment. Fig. 3(A) is a cross-sectional view taken along line AA in Fig. 1, i.e., a cross-sectional view taken along line BB in Fig. 1, i.e., a cross-sectional view taken along line BB in Fig. 1, i.e., a cross-sectional view taken along line BB in Fig. 1. The solar cell module 1 includes a surface layer 2, a back surface layer 3, first and second solar cell units 4 and 5 arranged between the surface layer 2 and the back surface layer 3 in this order from the surface layer 2 side, and a sealant 6 (not shown in Fig. 2) that seals the first and second solar cell units 4 and 5. Like the surface layer 2, the back surface layer 3 is made of glass.

[0016] The first solar cell unit 4 has a plurality of (e.g., four) strip-shaped first cells 40, which are arranged in parallel in the short direction. Each first cell 40 has a flexible strip-shaped film substrate 42 and a perovskite element 41 arranged on one surface of the film substrate 42 along its longitudinal direction, and is curved to match the curved shape of the solar cell module 1. The perovskite element 41 is a power generation element made from perovskite and is flexible like the film substrate 42. The film substrate 42 is made of a translucent resin material, primarily an insulating thermoplastic resin such as PET (polyethylene terephthalate) resin. The second solar cell unit 5 has a plurality of silicon crystal elements 51 arranged along the longitudinal direction of the first cells 40 so as to face the other surface of each film substrate 42. Here, the perovskite element 41 corresponds to the first power generating element in the present invention, and the silicon crystal element 51 is also a type of power generating element and corresponds to the second power generating element in the present invention. The silicon crystal element 51 may be either single crystal or polycrystalline.

[0017] As described above, the irradiated light passes through the surface layer 2 and then reaches the interior of the solar cell module 1. When this irradiated light first reaches the perovskite elements 41, depending on the wavelength range of the irradiated light, the irradiated light is absorbed by the perovskite elements 41 or passes through the perovskite elements 41 and is absorbed by the silicon crystal elements 51. Specifically, light with a wavelength range shorter than a predetermined value, such as visible light, is absorbed by the perovskite elements 41, while light with a wavelength range longer than a predetermined value, such as infrared light, is passed through the perovskite elements 41 and is absorbed by the silicon crystal elements 51. In other words, by stacking power generating elements with different absorbable wavelengths, it is possible to absorb light with wavelengths over a wide spectral range and convert the energy of the irradiated light into electrical energy with high conversion efficiency. The silicon crystal elements 51 are connected by connectors 52, and current flows throughout the second solar cell unit 5 via the connectors 52.

[0018] As described above, the solar cell module 1 is curved to match the curved shape of the roof substrate of the vehicle 7, and the curvature of the roof substrate in the vehicle length direction is greater than that in the vehicle width direction of the vehicle 7. Here, the curvature refers to the reciprocal of the radius (radius of curvature) of a circle when the locally curved portion (in the above example, the curved portion of the roof substrate) is approximated as part of a circle. Furthermore, the solar cell module 1 is curved along a first direction, and is curved more greatly along a second direction perpendicular to the first direction than in the first direction. When the solar cell module 1 is mounted on the roof substrate of the vehicle 7, it is mounted so that the first direction, which has a relatively small curvature, matches the vehicle width direction, and so that the second direction, which has a relatively large curvature, matches the vehicle length direction.

[0019] As shown in FIGS. 3A and 3B, the film substrate 42 is curved along its longitudinal direction to match the curvature of the solar cell module 1 along the second direction. The first cells 40 are arranged so that the longitudinal direction of the film substrate 42 coincides with the second direction. However, the film substrate 42 being curved along its longitudinal direction may cause the following problems. For example, when the solar cell module 1 is exposed to sunlight, the temperature distribution of the solar cell module 1 may not be uniform. This may result in localized stress being generated in the film substrate 42 due to differential elongation in the longitudinal direction of the film substrate 42 caused by temperature changes, resulting in the formation of fine wrinkles in the film substrate 42. This phenomenon is particularly likely to occur because the film substrate 42 is curved, potentially resulting in a decrease in the performance of the solar cell module 1.

[0020] For this reason, in this embodiment, a reinforced portion 42a having higher bending rigidity than other portions of the film substrate 42 is formed on an edge portion along the longitudinal direction of the film substrate 42. Here, bending rigidity is an index indicating the resistance of a member to bending deformation, and is the value obtained by dividing the bending moment by the curvature. Furthermore, the other portions are designated as non-reinforced portions 42b, and the perovskite element 41 is formed so as to cover the surface of the non-reinforced portions 42b. Note that it is sufficient to clearly show that the bending rigidity of the reinforced portion 42a is higher than that of the non-reinforced portion 42b, and since the level of bending rigidity can be evaluated by a method commonly used by those skilled in the art, detailed explanation thereof will be omitted.

[0021] By forming the reinforcing portions 42a on the edges along the longitudinal direction of the film substrate 42, it is possible to suppress deformation of the film substrate 42 due to differential elongation in the longitudinal direction of the film substrate 42. As a result, it is possible to suppress the occurrence of fine wrinkles in the film substrate 42, thereby suppressing a decrease in the performance of the solar cell module 1. Furthermore, since the first cell 40 is arranged so that the longitudinal direction of the film substrate 42 coincides with the second direction, the reinforcing portions 42a formed along the longitudinal direction of the film substrate 42 can effectively suppress the occurrence of fine wrinkles in the film substrate 42.

[0022] Note that when the resin constituting the reinforced portion 42a and the resin constituting the non-reinforced portion 42b are the same resin, the thickness of the reinforced portion 42a is greater than the thickness of the non-reinforced portion 42b. Specifically, the reinforced portion 42a may be formed by adhering the same resin as the resin constituting the non-reinforced portion 42b to the edge portion along the longitudinal direction of the film substrate 42, or the reinforced portion 42a may be formed by folding back the edge portion of the film substrate 42. Furthermore, when the reinforced portion 42a and the non-reinforced portion 42b are made of different types of resin, the reinforced portion 42a may be made of a metal material such as aluminum, titanium, or stainless steel, so that the Young's modulus of the material constituting the reinforced portion 42a is higher than the Young's modulus of the material constituting the non-reinforced portion 42b. Furthermore, the reinforced portion 42a may also be formed on the edge portion along the lateral direction of the film substrate 42.

[0023] However, because the reinforcing portion 42a is made of resin or metal, when light is irradiated onto the solar cell module 1, the light may not or may not easily penetrate the reinforcing portion 42a. In this case, when light is irradiated obliquely onto the reinforcing portion 42a, the shadow cast by the reinforcing portion 42a may be reflected on the silicon crystal element 51. This may result in the occurrence of hot spots, which may deteriorate the power generation performance of the solar cell module 1 over the long term. FIG. 3(C) shows an enlarged view of the area surrounded by the dashed line in FIG. 3(B). As shown in FIG. 3(C), the length of the perovskite element 41 in the lateral direction of the film substrate 42 is longer than the length of the silicon crystal element 51. Furthermore, when the solar cell module 1 is viewed from the thickness direction, the silicon crystal element 51 is positioned relative to the perovskite element 41 in such a way that the power generation region 41R of the perovskite element 41 remains on both sides of the lateral direction.

[0024] 3(C), even when light is irradiated obliquely onto the reinforcing portion 42a, the shadow portion cast by the reinforcing portion 42a is unlikely to be reflected on the silicon crystal element 51. As a result, the occurrence of hot spots in the silicon crystal element 51 due to the shadow portion cast on the silicon crystal element 51 can be suppressed.

[0025] FIG. 3(D) is an explanatory diagram schematically illustrating a manufacturing method of a solar cell module 1 according to this embodiment. FIG. 3(D) illustrates a manufacturing method of a curved, plate-shaped solar cell module 1. The manufacturing method includes a fabrication step and a heat-pressing step. Specifically, in the fabrication step, a laminate 1A is fabricated in which first and second solar cell units 4, 5 are arranged in order from the front panel 2A side to the back panel 3A side, with resin sealing sheets 6A-6C sandwiched between the curved, light-transmitting front panel 2A and the curved back panel 3A. At this time, first cells 40, each having a reinforcing portion 42a formed on an edge along the longitudinal direction of the film substrate 42, are arranged in parallel along the lateral direction of the film substrate 42. Silicon crystal elements 51 are arranged along the longitudinal direction of the film substrate 42 so as to face the other surface of each film substrate 42 along the longitudinal direction.

[0026] In the heat-pressing step, a laminator is used to heat-press the laminate 1A produced in the manufacturing step at a heating temperature above the softening point of the resin of the encapsulating sheets 6A-6C until the first and second solar cell units 4, 5 are encapsulated with the resin. Specifically, the laminate 1A is placed on a laminating jig (not shown), and this laminating jig is placed on the heater plate 8 of the laminator. The chamber (not shown) is then sealed and thoroughly degassed to prevent the inclusion of air or other contaminants. After thorough degassing, a heater 81 built into the heater plate 8 heats the resin of the encapsulating sheets 6A-6C at a heating temperature above the softening point of the resin to soften it. At this time, the inside of the laminator is opened to atmospheric pressure, and a diaphragm 9 presses the laminate 1A from above at atmospheric pressure (100 kPa). Thereafter, the softened resin of sealing sheets 6A-6C is cross-linked and adheres to seal first and second solar cell units 4 and 5, thereby completing the heat-pressing step.

[0027] In the above manufacturing process, the front panel 2A, the back panel 3A, and the encapsulating sheets 6A-6C correspond to the front layer 2, the back layer 3, and the encapsulant 6 of the completed solar cell module 1, respectively. In the completed solar cell module 1, as described above, the first solar cell unit 4 has a plurality of strip-shaped first cells 40, and each first cell 40 has a flexible strip-shaped film substrate 42 and a perovskite element 41 arranged on one surface of the film substrate 42 along its longitudinal direction. The second solar cell unit 5 has a plurality of silicon crystal elements 51, and the longitudinal edge of the film substrate 42 is formed with a reinforcing portion 42a having a higher bending rigidity than the non-reinforced portion 42b. Therefore, in the heat-pressing process, each first cell 40 of the first solar cell unit 4 arranged between the front panel 2A and the back panel 3A is curved in accordance with the curved shapes of the front panel 2A and the back panel 3A. At this time, the reinforcing portions 42a along the edges of the film substrate 42 suppress the occurrence of wrinkles in the first cells 40 due to thermal shrinkage of the film substrate 42. As a result, the deterioration of the performance of the solar cell module 1 can be suppressed.

[0028] For example, a modified example of the solar cell module 1 shown in FIG. 1 will be described. FIG. 4(A) schematically shows a state in which a solar cell module 1 according to the modified example is mounted as part of the roof 71 of a vehicle 7. FIG. 4(B) is a cross-sectional view taken along CC in FIG. 4(A). Since the solar cell module 1 is required to be mounted on the vehicle 7 as at least part of the roof 71, a difference from FIG. 1 is that the solar cell module 1 may be part of the roof 71 itself, as shown in FIG. 4(A). Specifically, the solar cell module 1 shown in FIG. 4(A) is a sunroof. Furthermore, the curvature of the roof 71 of the vehicle 7 shown in FIG. 4(A) is greater in the vehicle width direction (the left-right direction in the orientation of FIG. 4(A)) than in the vehicle length direction (the up-down direction in the orientation of FIG. 4(A)). Accordingly, the solar cell module 1 is mounted as part of the roof 71 so that the roof 71 has a shape with a greater curvature in the vehicle width direction. That is, the reinforcing portion 42a for suppressing deformation of the film substrate 42 is arranged along the vehicle width direction when the solar cell module 1 is mounted as part of the roof 71. The first cells 40 are arranged at a fixed interval S. Neither the first nor the second solar cell units 4, 5 are arranged in the space that defines the interval S. Therefore, as shown in FIG. 4(B), sunlight irradiated from outside can be admitted into the interior of the vehicle 7 through the front surface layer 2, the interval S, and the back surface layer 3.

[0029] As an alternative embodiment to the above, FIG. 5(A) schematically illustrates a solar cell module 1 in which a plurality of silicon crystal elements 51 arranged in parallel in two rows are entirely contained in a single second cell 50. FIG. 5(B) is a cross-sectional view taken along the line DD in FIG. 5(A). In each second cell 50, the plurality of silicon crystal elements 51 are arranged more closely together in two rows. Even in this case, the width in the transverse direction of the second cell 50 can be made shorter than the width in the same direction of the perovskite element 41, thereby leaving the power generation region 41R of the perovskite element 41. Here, the width in the transverse direction of the second cell 50 refers to the distance between the left end of the left silicon crystal element 51 and the right end of the right silicon crystal element 51 of the two silicon crystal elements 51 in the orientation shown in FIG. 5(B). As a result, even in a configuration in which the entirety of the multiple silicon crystal elements 51 arranged in two parallel rows is included in one second cell 50, even when the reinforcing portion 42a is irradiated with light from an oblique direction, the shadows cast by the reinforcing portion 42a are unlikely to be reflected on the silicon crystal elements 51. As a result, the occurrence of hot spots in the silicon crystal elements 51 due to the shadows cast on the silicon crystal elements 51 can be suppressed. [Explanation of symbols]

[0030] 1: solar cell module, 1A: laminate, 2: surface layer, 2A: surface panel, 3: back layer, 3A: back panel, 4: first solar cell unit, 40: first cell, 41: perovskite element, 41R: power generation region, 42: film substrate, 42a: reinforcing portion, 5: second solar cell unit, 51: silicon crystal element, 6: sealing material, 6A-6C: sealing sheets, 7: vehicle, 71: roof

Claims

1. A curved plate-shaped solar cell module, a light-transmitting surface layer; A backing layer; first and second solar cell units disposed between the front surface layer and the back surface layer in this order from the front surface layer side; a sealing material that seals the first and second solar cell units, the first solar cell unit has a plurality of strip-shaped first cells; the plurality of first cells are arranged in parallel in a short-side direction of the first cells, each of the first cells has a flexible strip-shaped film substrate and a first power generating element disposed on one surface of the film substrate along a longitudinal direction of the film substrate, and is curved according to the curved shape of the solar cell module; the second solar cell unit has a plurality of second power generating elements arranged along the longitudinal direction of the film substrate so as to face the other surface of each of the film substrates along the longitudinal direction of the first cell, A solar cell module, characterized in that a reinforcing portion having higher bending rigidity than other portions of the film substrate is formed on an edge portion along the longitudinal direction of the film substrate.

2. In the short-side direction of the film substrate, the length of the first power generating element is longer than the length of the second power generating element, 2. The solar cell module according to claim 1, wherein, when the solar cell module is viewed from the thickness direction, in the short side direction, the second power generation element is arranged relative to the first power generation element so as to leave a power generation region of the first power generation element on both sides along the short side direction.

3. the solar cell module is curved along a first direction and curved along a second direction perpendicular to the first direction to a greater extent than the curvature in the first direction; The solar cell module according to claim 1 , wherein the first cells are arranged so that the longitudinal direction of the first cells coincides with the second direction.

4. A vehicle having the solar cell module according to claim 3 mounted as at least a part of the roof.

5. A method for manufacturing a curved plate-shaped solar cell module, comprising: the solar cell module includes first and second solar cell units; the first solar cell unit has a plurality of strip-shaped first cells, each of the first cells having a flexible strip-shaped film substrate and a first power generating element disposed on one surface of the film substrate along a longitudinal direction of the film substrate; the second solar cell unit has a plurality of second power generating elements, The manufacturing method includes: a fabrication step of fabricating a laminate in which first and second solar cell units are arranged in this order from the front panel side so that a resin sealing sheet is sandwiched between a curved front panel and a curved back panel having light transmission; a heat-pressing step of heat-pressing the laminate at a heating temperature equal to or higher than the softening point of the resin until the first and second solar cell units are sealed with the resin of the sealing sheet, In the manufacturing process, the first cells each having a reinforcing portion formed on an edge portion along the longitudinal direction of the film substrate and having a bending rigidity higher than that of other portions of the film substrate are arranged in parallel in a lateral direction of the first cells; A method for manufacturing a solar cell module, characterized in that the second power generating elements are arranged along the longitudinal direction of the film substrate so as to face the other surface of each of the film substrates along the longitudinal direction of the first cells.

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