Solar cell module

Abstract

To provide a solar cell module capable of improving power generation efficiency.SOLUTION: The solar cell module according to the first aspect of the embodiment has a solar cell element including a first cell and a second cell. When a thickness direction of the first cell and the second cell is defined as a first direction, the first cell and the second cell are arranged side by side in the first direction. The first cell is disposed on a first side of the second cell in a first direction. The solar cell module has a sealing material covering a first side in a first direction. When a direction orthogonal to the first direction is defined as a second direction, the solar cell module includes an optical path adjusting member disposed at least on a first side of the second cell in the second direction. The optical path adjusting member includes a light transmitting member having a refractive index smaller than that of the sealing material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a solar cell module. [Background technology]

[0002] Solar cell modules including tandem solar cell elements are currently in use, and solar cell modules are required to have high power generation efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-7384 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a solar cell module that can improve power generation efficiency. [Means for solving the problem]

[0005] A solar cell module according to a first embodiment has a solar cell element including a first cell and a second cell. When the thickness direction of the first cell and the second cell is defined as a first direction, the first cell and the second cell are arranged side by side in the first direction. The first cell is arranged on a first side of the second cell in the first direction. The solar cell module has a sealing material covering the first side in the first direction. When a direction perpendicular to the first direction is defined as a second direction, the solar cell module has an optical path adjustment member arranged on at least the first side of the second cell in the second direction. The optical path adjustment member includes a light-transmitting member having a refractive index smaller than that of the sealing material.

[0006] The solar cell module of Aspect 2 is based on the solar cell module of Aspect 1. The optical path adjusting member includes a light reflecting member having a light reflecting surface. When the side opposite to the first side in the second direction is the second side in the second direction, the light reflecting surface faces between the first side in the first direction and the second side in the second direction.

[0007] A solar cell module of Aspect 3 is based on the solar cell module of Aspect 1 or 2. The first cell has a first positive terminal and a first negative terminal. The second cell is electrically isolated from the first cell and has a second positive terminal and a second negative terminal.

[0008] The solar cell module of aspect 4 is based on the solar cell module of any one of aspects 1 to 3. When a direction perpendicular to the first and second directions is defined as a third direction, a plurality of solar cell elements are arranged at intervals in the second and third directions. The light path adjustment member fills the gaps between the second cells of the solar cell elements adjacent to each other in the second and third directions.

[0009] The solar cell module of aspect 5 is based on the solar cell module of any one of aspects 1 to 4. When a direction perpendicular to the first and second directions is defined as a third direction, a plurality of solar cell elements are arranged side by side in at least the third direction. The solar cell module has wiring. The wiring extends in the third direction and connects first cells of the plurality of solar cell elements arranged side by side in the third direction. The wiring is formed at least at the end of the solar cell element on the first side in the second direction.

[0010] A solar cell module of aspect 6 is based on the solar cell module of any one of aspects 1 to 5. The thickness of the light path adjusting member in the first direction is equal to the thickness of the second cell in the first direction. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. [Figure 2] FIG. 1 is a cross-sectional view of a solar cell module according to a first embodiment. [Figure 3]FIG. 1 is an explanatory diagram of a four-terminal solar cell module 1. [Figure 4] 5A and 5B are explanatory diagrams illustrating the optical path adjusting action of the optical path adjusting member in the first embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a solar cell module according to a second embodiment. [Figure 6] 10A and 10B are explanatory diagrams illustrating the optical path adjusting action of the optical path adjusting member in the second embodiment. [Figure 7] 10 is a graph showing the relationship between the angle of incidence of light on a solar cell module and the increase in the amount of light incident on a solar cell element. [Figure 8] FIG. 10 is a cross-sectional view of a solar cell module according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a solar cell module according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, solar cell modules according to embodiments will be described with reference to the drawings. Fig. 1 is a plan view of a solar cell module 1. Fig. 1 shows a state in which a sealing material 3 has been removed. Fig. 2 is a cross-sectional view of the solar cell module 1 of the first embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is an explanatory diagram of a four-terminal solar cell module 1.

[0013] In the present application, the Z direction, Y direction, and X direction of the Cartesian coordinate system are defined as follows: The Z direction (first direction) is the thickness direction of the top cell (first cell) 10 and the bottom cell (second cell) 20 included in the solar cell module 1. The +Z side (first side of the first direction) is the direction in which the top cell 10 is arranged when viewed from the bottom cell 20. The Y direction (third direction) is the direction in which the positive electrode wiring 14a and negative electrode wiring 14b connecting the top cells 10 of the multiple solar cell elements 5 extend. The X direction (second direction) is the direction perpendicular to the Z direction and the Y direction.

[0014] As shown in FIG. 2, the solar cell module 1 includes a solar cell element 5, a sealing material (first sealing material) 3, and a back sheet 8. The solar cell element 5 is a tandem solar cell element 5 having a top cell 10 and a bottom cell 20. The top cell 10 and the bottom cell 20 are arranged side by side in the Z direction. The top cell 10 is arranged on the +Z side of the bottom cell 20. The top cell 10 and the bottom cell 20 absorb light in different wavelength bands. The power generation layer of the top cell 10 includes a transparent cuprous oxide (CuO) semiconductor, a perovskite semiconductor, or the like. The power generation layer of the bottom cell 20 includes a silicon (Si) semiconductor, or the like. As shown in FIG. 3, light that passes through the light-transmitting power generation layer of the top cell 10 reaches the power generation layer of the bottom cell 20.

[0015] As shown in FIG. 1, a plurality of solar cell elements 5 are aligned in a matrix and spaced apart in the X and Y directions. The solar cell module 1 has positive wiring (wiring) 14a and negative wiring (wiring) 14b. The positive wiring 14a and negative wiring 14b extend in the Y direction. The positive wiring 14a and negative wiring 14b connect top cells 10 of a plurality of solar cell elements 5 aligned in the Y direction. As shown in FIG. 2, the positive wiring 14a and negative wiring 14b are arranged on the +Z side surface of the top cell 10. The positive wiring 14a is arranged at one end of the top cell 10 in the X direction, and the negative wiring 14b is arranged at the other end of the top cell 10 in the X direction.

[0016] As shown in FIG. 1 , the solar cell module 1 has a positive electrode output wiring 15a and a negative electrode output wiring 15b. The positive electrode output wiring 15a and the negative electrode output wiring 15b extend in the X direction. The positive electrode output wiring 15a is disposed on the −Y side of the solar cell module 1, and the negative electrode output wiring 15b is disposed on the +Y side. The positive electrode output wiring 15a is connected to the positive electrode wiring 14a, and the negative electrode output wiring 15b is connected to the negative electrode wiring 14b. As a result, the top cells 10 of the multiple solar cell elements 5 are electrically connected in parallel, but may also be connected in series.

[0017] The bottom cells 20 of the plurality of solar cell elements 5 are electrically connected in series. The bottom cells 20 of the plurality of solar cell elements 5 may be connected in a combination of series and parallel.

[0018] As shown in FIG. 3, the top cells 10 and bottom cells 20 of the multiple solar cell elements 5 are electrically separated. The top cells 10 of the multiple solar cell elements 5 have a first positive electrode terminal 10a and a first negative electrode terminal 10b. The first positive electrode terminal 10a is connected to the positive electrode output wiring 15a (see FIG. 1), and the first negative electrode terminal 10b is connected to the negative electrode output wiring 15b. The bottom cells 20 of the multiple solar cell elements 5 have a second positive electrode terminal 20a and a second negative electrode terminal 20b. In this way, the solar cell module 1 is a four-terminal type. The solar cell module 1 may also be a two-terminal type in which the top cells 10 and bottom cells 20 are electrically connected.

[0019] The encapsulant 3 is made of a resin material such as polyolefin or ethylene-vinyl acetate (EVA) copolymer. The encapsulant 3 is optically transparent. As shown in FIG. 2, the encapsulant 3 covers the +Z side of the solar cell module 1. A front sheet such as glass or a transparent film may be disposed on the +Z side of the encapsulant 3. The back sheet 8 is made of a resin material etc. The back sheet 8 covers the −Z side of the solar cell module 1.

[0020] The solar cell module 1 is manufactured as follows. The top cell 10 and the bottom cell 20 of the solar cell element 5 are individually formed. The multiple solar cell elements 5 are aligned and arranged on the surface of the back sheet 8. The top cells 10 of the multiple solar cell elements 5 are connected by positive electrode wiring 14a and negative electrode wiring 14b. A sealant sheet is arranged on the +Z side of the multiple solar cell elements 5. The dimensions of the sealant sheet in the X and Y directions are equal to the dimensions of the solar cell module 1. The entire solar cell module 1 is heated in a vacuum furnace. The sealant sheet melts, and the +Z side of the solar cell module 1 is laminated with sealant 3. Furthermore, sealant 3 is filled between the solar cell elements 5 adjacent in the X and Y directions.

[0021] An intermediate encapsulant sheet may be disposed between the top cell 10 and the bottom cell 20. The material of the intermediate encapsulant sheet is the same as that of the encapsulant sheet. The dimensions of the intermediate encapsulant sheet in the X and Y directions are equal to the dimensions of the solar cell module 1. The intermediate encapsulant sheet is heated and melted together with the encapsulant sheet in a vacuum furnace. As a result, a second encapsulant (not shown) is disposed between the top cell 10 and the bottom cell 20. Furthermore, the second encapsulant, together with the encapsulant 3, is filled between the solar cell elements 5 adjacent to each other in the X and Y directions.

[0022] A bottom encapsulant sheet may be disposed between the bottom cell 20 and the back sheet 8. The bottom encapsulant sheet is heated and melted together with the encapsulant sheet in a vacuum furnace, thereby disposing a third encapsulant (not shown) between the bottom cell 20 and the back sheet 8.

[0023] (First embodiment) As shown in FIGS. 1 and 2 , the solar cell module 1 has a light path adjustment member 30. The width of the light path adjustment member 30 is equal to the spacing between adjacent solar cell elements 5 in the X and Y directions. The light path adjustment member 30 fills the gap between the bottom cells 20 of adjacent solar cell elements 5 in the X and Y directions. When viewed from the +Z side, the light path adjustment member 30 is formed in a lattice shape. The solar cell elements 5 are positioned by the lattice-shaped light path adjustment member 30. The lattice-shaped light path adjustment member 30 also functions as a reinforcing member for the solar cell module 1, suppressing local bending of the solar cell module 1.

[0024] The thickness of the light path adjusting member 30 in the Z direction is equal to or greater than the thickness of the bottom cell 20 in the Z direction. In the example of FIG. 2, the thickness of the light path adjusting member 30 in the Z direction is equal to the thickness of the bottom cell 20 in the Z direction. In this case, the intermediate sealing material sheet can be placed in a flat state on the +Z side of the bottom cell 20 and the light path adjusting member 30. This suppresses misalignment of the top cell 10 placed on the +Z side of the intermediate sealing material sheet, simplifying the manufacturing process.

[0025] The light path adjusting member 30 of the solar cell module 1 of the first embodiment is a light transmitting member 31. The light transmitting member 31 is formed of a light-transmitting resin material or the like. The light transmitting member 31 has a smaller refractive index than the encapsulant 3. For example, the refractive index of polyolefin that can be used as the encapsulant 3 is approximately 1.485, and the refractive index of EVA is approximately 1.482. In contrast, the refractive index of amorphous fluororesin that can be used as the light transmitting member 31 is approximately 1.34, the refractive index of polytetrafluoroethylene resin is approximately 1.35, the refractive index of acrylate is approximately 1.375, and the refractive index of amorphous fluororesin is approximately 1.30.

[0026] The manufacturing method of the solar cell module 1 including the light-transmitting member 31 is as follows. A light-transmitting member sheet is placed on the surface on the +Z side of the back sheet 8. The light-transmitting member sheet is partially removed in the places where the solar cell elements 5 are to be placed. This forms the light-transmitting member 31 in a lattice pattern. The solar cell elements 5 are fitted into the parts where the light-transmitting member sheet has been removed. The solar cell elements 5 are positioned by the lattice-shaped light-transmitting member 31.

[0027] 4 is an explanatory diagram of the light path adjusting action of the light path adjusting member 30 in the first embodiment. Light is incident from outside the solar cell module 1 onto the boundary surface between air and the sealing material 3. The refractive index of the sealing material 3 is greater than the refractive index of air (=1). The refraction angle θA (the exit angle from the boundary surface) is smaller than the incident angle θair to the sealing material 3 (boundary surface) (Snell's law).

[0028] Consider a comparative example in which the encapsulant 3 is filled in place of the light-transmitting member 31. In this comparative example, only the encapsulant 3 is filled between adjacent solar cell elements 5. The light incident on the solar cell module 1 of the comparative example is referred to as comparative light C0. The comparative light C0 travels in a straight line inside the encapsulant 3. A portion of the comparative light C0 is incident on the lower end 20d on the -Z side of the side of the bottom cell 20 of the solar cell element 5. The comparative light C0 incident on the lower end 20d is the limit comparative light LC0. In Figure 4, the optical path of the limit comparative light LC0 is shown by a dashed line. When the incident angle θair on the encapsulant 3 is the same, the limit on the +X side of the comparative light C0 incident on the side of the bottom cell 20 is the limit comparative light LC0.

[0029] Consider the first embodiment, which includes the light-transmitting member 31. The light incident on the solar cell module 1 of the first embodiment is designated as first practical light E1. The first practical light E1 is refracted at the interface between the encapsulant 3 and the light-transmitting member 31. As described above, the refractive index of the light-transmitting member 31 is smaller than that of the encapsulant 3. The refraction angle θB is larger than the incident angle θA on the light-transmitting member 31. The first practical light E1 incident on the lower end 20d of the side surface of the bottom cell 20 is the limit first practical light LE1. In FIG. 4, the optical path of the limit first practical light LE1 is indicated by a solid line. When the incident angle θair on the encapsulant 3 is the same, the limit on the +X side of the first practical light E1 incident on the side surface of the bottom cell 20 is the limit first practical light LE1. The incident position of the limit first practical light LE1 on the encapsulant 3 is a distance D1 away from the incident position of the limit comparative light LC0 on the encapsulant 3. In the first embodiment, compared to the comparative example, the amount of light incident on the side surface of the bottom cell 20 increases by the amount of the first example light E1 incident on the sealing material 3 within the range of the distance D1.

[0030] As described above in detail, the solar cell module 1 of the first embodiment has a solar cell element 5 including a top cell 10 and a bottom cell 20. When the thickness direction of the top cell 10 and the bottom cell 20 is defined as the Z direction, the top cell 10 and the bottom cell 20 are arranged side by side in the Z direction. The top cell 10 is arranged on the +Z side of the bottom cell 20. The solar cell module 1 has a sealing material 3 that covers the +Z side. When the direction perpendicular to the Z direction is defined as the X direction, the solar cell module 1 has at least an optical path adjustment member 30 arranged on the +X side of the bottom cell 20. The optical path adjustment member 30 includes a light-transmitting member 31 with a refractive index smaller than that of the sealing material 3.

[0031] According to this configuration, the refractive index of the light-transmitting member 31 is smaller than the refractive index of the sealing material 3, so the refraction angle θB is larger than the incident angle θA on the light-transmitting member 31. The first light E1 is refracted toward the solar cell element 5 and is incident on the side surface of the solar cell element 5. This increases the amount of light incident on the solar cell element 5, thereby improving the power generation efficiency of the solar cell module 1.

[0032] The top cell 10 has a first positive electrode terminal 10a and a first negative electrode terminal 10b. The bottom cell 20 is electrically isolated from the top cell 10 and has a second positive electrode terminal 20a and a second negative electrode terminal 20b. The four-terminal solar cell module 1 does not require current matching between the top cell 10 and the bottom cell 20. Therefore, the power generation efficiency of the solar cell module 1 can be increased in proportion to an increase in the amount of light incident on the solar cell element 5.

[0033] When the direction perpendicular to the Z and X directions is defined as the Y direction, the multiple solar cell elements 5 are arranged at intervals in the X and Y directions. The light path adjusting member 30 fills the gap between the bottom cells 20 of the solar cell elements 5 adjacent to each other in the X and Y directions. According to this configuration, the light path adjusting member 30 is formed in a lattice shape. The solar cell element 5 is positioned in the X direction and the Y direction by the lattice-shaped light path adjusting member 30. The light path adjusting member 30 also functions as a reinforcing material for the solar cell module 1.

[0034] When the direction orthogonal to the Z direction and the X direction is defined as the Y direction, multiple solar cell elements 5 are arranged side by side at least in the Y direction. The solar cell module 1 has positive electrode wiring 14a and negative electrode wiring 14b. The positive electrode wiring 14a and negative electrode wiring 14b extend in the Y direction and connect the top cells 10 of the multiple solar cell elements 5 arranged side by side in the Y direction. The positive electrode wiring 14a is formed at the end of the solar cell element 5 on the +X side.

[0035] The formation of the positive electrode wiring 14a reduces the amount of light incident on the end portion on the +X side of the solar cell element 5. As described above, the light path adjusting member 30 is disposed at least on the +X side of the solar cell element 5. The light path adjusting member 30 increases the amount of light incident on the side surface of the solar cell element 5. This can improve the power generation efficiency of the solar cell module 1.

[0036] The thickness of the optical path adjusting member 30 in the Z direction is equal to the thickness of the bottom cell 20 in the Z direction. According to this configuration, the intermediate sealing material sheet can be placed in a flat state on the +Z side of the bottom cell 20 and the optical path adjusting member 30. This suppresses misalignment of the top cell 10 placed on the +Z side of the intermediate sealing material sheet, simplifying the manufacturing process.

[0037] (Second embodiment) 5 is a cross-sectional view of a solar cell module 1 according to a second embodiment. The solar cell module 1 according to the second embodiment differs from the first embodiment in that the light path adjusting member 30 includes a light reflecting member 33. Explanation of the second embodiment in respect to the same points as the first embodiment may be omitted.

[0038] The light path adjusting member 30 includes a light reflecting member 33 in addition to a light transmitting member 31. The light reflecting member 33 has a light reflecting surface 34. The light reflecting surface 34 is covered with a material with high light reflectivity. The material with high light reflectivity is, for example, a metal material such as aluminum. The main body of the light reflecting member 33 excluding the light reflecting surface 34 is formed of a resin material or the like. The entire light reflecting member 33 may be formed of a material with high light reflectivity.

[0039] The light reflecting member 33 is formed in a mountain shape with its apex located at the midpoint between adjacent solar cell elements 5. The slope of the mountain-shaped light reflecting member 33 is the light reflecting surface 34. The width of the light reflecting member 33 is equal to the width of the light path adjusting member 30. The thickness in the Z direction of the portion where the apex of the light reflecting member 33 is located is equal to the thickness in the Z direction of the light path adjusting member 30. The light transmitting member 31 is disposed on the +Z side of the light reflecting surface 34 of the light reflecting member 33. The thickness in the Z direction of the light path adjusting member 30, which is the sum of the light reflecting member 33 and the light transmitting member 31, is equal to or greater than the thickness in the Z direction of the bottom cell 20. In the example of FIG. 5 , the thickness in the Z direction of the light path adjusting member 30 is equal to the thickness in the Z direction of the bottom cell 20.

[0040] The solar cell module 1 including the light-reflecting member 33 is manufactured as follows. A resin sheet that will become the main body of the light-reflecting member 33 is placed on the +Z side surface of the back sheet 8. The resin sheet is partially removed from the location where the solar cell element 5 is to be placed. The resin sheet is pressed in the Z direction to form an inclined surface that will become the light-reflecting surface 34. The inclined surface is covered with a material with high light reflectivity to form the light-reflecting surface 34. A resin material that will become the light-transmitting member 31 is molded on the +Z side of the light-reflecting surface 34. Thereafter, the solar cell module 1 is manufactured in the same manner as in the first embodiment.

[0041] Light reflecting member 33, which is disposed on the +X side of solar cell element 5, has light reflecting surface 34 facing the +Z side and the -X side. This light reflecting surface 34 is inclined toward the -Z side toward the -X side. As a result, light that travels toward the -Z side and is incident on light reflecting surface 34 is reflected toward the -X side. The reflected light is incident on the side surface of bottom cell 20 of solar cell element 5, which is disposed on the -X side of light reflecting member 33.

[0042] In this way, the light reflecting member 33 arranged on the +X side of the solar cell element 5 has a light reflecting surface 34 facing the +Z side and the -X side. Similarly, the light reflecting member 33 arranged on the -X side of the solar cell element 5 has a light reflecting surface 34 facing the +Z side and the +X side. Furthermore, the light reflecting member 33 arranged on the +Y side of the solar cell element 5 has a light reflecting surface 34 facing the +Z side and the -Y side. Similarly, the light reflecting member 33 arranged on the -Y side of the solar cell element 5 has a light reflecting surface 34 facing the +Z side and the +Y side. As a result, light that travels on the -Z side and is incident on the light reflecting surface 34 is reflected toward the solar cell element 5.

[0043] In FIG. 5, the optical path of the limit comparative light LC0 of the comparative embodiment described above is indicated by a dashed line. The light incident on the solar cell module 1 of the second embodiment, which has the light reflecting member 33, is referred to as second practical light E2. A portion of the second practical light E2 is reflected by the light reflecting surface 34 of the light reflecting member 33 and enters the upper end 20u on the +Z side of the side of the bottom cell 20. The second practical light E2 that enters the upper end 20u is the limit second practical light LE2. In FIG. 4, the optical path of the limit second practical light LE2 is indicated by a solid line. When the angle of incidence θair on the encapsulant 3 is the same, the limit on the +X side of the second practical light E2 that enters the side of the bottom cell 20 is the limit second practical light LE2. The incident position of the limit second practical light LE2 on the encapsulant 3 is a distance D2 away from the incident position of the limit comparative light LC0 on the encapsulant 3. In the second embodiment, compared to the comparative embodiment, the amount of light incident on the side surface of the bottom cell 20 increases by the amount of second example light E2 incident on the encapsulant 3 within the range of distance D2. Because distance D2 is large, in the second embodiment, the amount of light incident on the side surface of the bottom cell 20 increases significantly compared to the comparative embodiment.

[0044] FIG. 6 is an explanatory diagram of the light path adjustment function of the light path adjustment member 30 in the second embodiment. FIG. 6 shows the case where the incident angle θair to the encapsulant 3 is 0°. The aforementioned comparative light C0 does not enter the side surface of the bottom cell 20 when the incident angle θair is 0°. In contrast, the second practical light E2 is reflected by the light reflecting surface 34 of the light reflecting member 33 and enters the side surface of the bottom cell 20, even when the incident angle θair is 0°. The incident position of the limit second practical light LE2 to the encapsulant 3 is located a distance D2 on the +X side from the side surface of the solar cell element 5. In the second embodiment, compared to the comparative embodiment, the amount of light entering the side surface of the bottom cell 20 increases by the amount of the second practical light E2 entering the encapsulant 3 within the distance D2.

[0045] The light reflecting member 33, which is shaped like a mountain, has light reflecting surfaces 34 on both sides of the apex in the X direction. The light reflecting surface 34 on the -X side allows the second effective light E2 to be incident on the solar cell element 5 on the -X side. The second effective light E2 is incident on the encapsulant 3 within a range of distance D2 from the side surface of the solar cell element 5 on the -X side to the +X side, and is incident on the solar cell element 5 on the -X side. The light reflecting surface 34 on the +X side allows the second effective light E2 to be incident on the solar cell element 5 on the +X side. The second effective light E2 is incident on the encapsulant 3 within a range of distance D2 from the side surface of the solar cell element 5 on the +X side to the -X side, and is incident on the solar cell element 5 on the +X side. Therefore, in the second embodiment, compared to the comparative embodiment, the amount of light incident on the side surface of the bottom cell 20 is increased by the amount of the second effective light E2 incident on the encapsulant 3 within a range twice the distance D2 (D2 × 2).

[0046] FIG. 7 is a graph showing the relationship between the incident angle θair of light to the encapsulant 3 and the increase in the amount of light incident on the solar cell element 5. The dashed-dotted line shows the change in distance D1 when the incident angle θair to the encapsulant 3 is changed in the first embodiment. The two-dot-dash line shows the change in distance D2×2 when the incident angle θair to the encapsulant 3 is changed in the second embodiment. The dashed line shows the change in distance D2×2 when the incident angle θair to the encapsulant 3 is changed in the case where the light path adjusting member 30 includes only the light reflecting member 33 (does not include the light transmitting member 31). Regardless of the incident angle θair, the distance D2×2 in the second embodiment is larger than the distance D1 in the first embodiment. It can be seen that the amount of light incident on the solar cell element 5 is increased in the second embodiment compared to the first embodiment.

[0047] As described above in detail, the solar cell module 1 of the second embodiment has at least the light path adjustment member 30 arranged on the +X side of the bottom cell 20. The light path adjustment member 30 includes a light reflecting member 33 having a light reflecting surface 34. When the side opposite the +X side is defined as the -X side, the light reflecting surface 34 faces between the +Z side and the -X side. According to this configuration, the second effective light E2 is reflected by the light reflecting surface 34 of the light reflecting member 33 and enters the side surface of the solar cell element 5. This increases the amount of light incident on the solar cell element 5, thereby improving the power generation efficiency of the solar cell module.

[0048] (Third embodiment) 8 is a cross-sectional view of a solar cell module 1 of a third embodiment. The solar cell module 1 of the third embodiment differs from the second embodiment in the position on the +Z side of the light transmitting member 31 included in the light path adjusting member 30. Explanation of the third embodiment in respect to the same points as the second embodiment may be omitted.

[0049] The thickness in the Z direction of the light path adjusting member 30 in the third embodiment is equal to the thickness in the Z direction of the solar cell element 5. The light path adjusting member 30 includes a light transmitting member 31 and a light reflecting member 33. The shape of the light reflecting member 33 is the same as in the second embodiment. The position of the +Z side of the light transmitting member 31 is on the +Z side of the solar cell element 5. The sealing material 3 arranged between adjacent top cells 10 in the second embodiment is replaced with the light transmitting member 31 in the third modified example.

[0050] As described above, the light path adjusting member 30 functions as a reinforcing material for the solar cell module 1. The thickness of the light path adjusting member 30 in the Z direction in the third embodiment is equal to the thickness of the solar cell element 5 in the Z direction. This can enhance the function of the light path adjusting member 30 as a reinforcing material.

[0051] The light incident on the solar cell module 1 of the third embodiment is referred to as third effective light E3. The third effective light E3 is refracted toward the solar cell element 5 at the boundary between the encapsulant 3 and the light-transmitting member 31. The third effective light E3 is reflected by the light-reflecting surface 34 of the light-reflecting member 33 and enters the side surface of the bottom cell 20. The third effective light E3 entering the upper end 20u of the side surface of the bottom cell 20 is the limit third effective light LE3. In FIG. 8, the optical path of the limit third effective light LE3 is indicated by a solid line. The boundary between the encapsulant 3 and the light-transmitting member 31 is located closer to the +Z direction than in the second embodiment. Therefore, the incident position of the limit third effective light LE3 on the encapsulant 3 is closer to the +X direction than the incident position of the limit second effective light LE2 on the encapsulant 3 shown in FIG. 4. In the third embodiment, the amount of light incident on the side surface of the bottom cell 20 is increased compared to the second embodiment.

[0052] (Fourth embodiment) 9 is a cross-sectional view of a solar cell module 1 of the fourth embodiment. The solar cell module 1 of the fourth embodiment differs from the third embodiment in the thickness in the Z direction of the light reflecting member 33 included in the light path adjusting member 30. Explanation of the fourth embodiment in respect to the same points as the third embodiment may be omitted.

[0053] The thickness in the Z direction of the light path adjusting member 30 in the fourth embodiment is equal to the thickness in the Z direction of the solar cell element 5. The light path adjusting member 30 includes a light transmitting member 31 and a light reflecting member 33. The thickness in the Z direction of the portion where the vertex of the light reflecting member 33 is located is greater than the thickness in the Z direction of the bottom cell 20. The inclination angle of the light reflecting surface 34 with respect to the surface on the +Z side of the back sheet 8 is defined as α. The inclination angle α of the light reflecting surface 34 in the fourth embodiment is greater than that in the third embodiment.

[0054] The light incident on the solar cell module 1 of the fourth embodiment is referred to as fourth example light E4. The fourth example light E4 is reflected by the light reflecting surface 34 of the light reflecting member 33 and enters the side surface of the solar cell element 5. The fourth example light E4 is incident on the top cell 10 as well as the bottom cell 20 of the solar cell element 5. By adjusting the thickness of the light reflecting member 33 in the Z direction, the ratio of the amount of incident light of the fourth example light E4 to the bottom cell 20 and the top cell 10 can be adjusted.

[0055] According to at least one of the embodiments described above, the solar cell module 1 has at least the light path adjustment member 30 disposed on the +X side of the bottom cell 20. The light path adjustment member 30 includes a light transmitting member 31 having a refractive index smaller than that of the sealing material 3. This can increase the power generation efficiency of the solar cell module 1.

[0056] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0057] 1...solar cell module, 3...encapsulant, 5...solar cell element, 10...top cell, 10a...first positive electrode terminal, 10b...first negative electrode terminal, 14a...positive electrode wiring (wiring), 14b...negative electrode wiring, 20...bottom cell, 20a...second positive electrode terminal, 20b...second negative electrode terminal, 30...light path adjustment member, 31...light-transmitting member, 33...light-reflecting member, 34...light-reflecting surface.

Claims

1. a solar cell element including a first cell and a second cell; When a thickness direction of the first cell and the second cell is defined as a first direction, the first cell and the second cell are arranged side by side in the first direction, and the first cell is arranged on a first side of the second cell in the first direction; a sealing material covering the first side in the first direction; When a direction orthogonal to the first direction is defined as a second direction, the optical path adjusting member is disposed at least on a first side of the second cell in the second direction, the optical path adjustment member includes a light transmitting member having a refractive index smaller than that of the sealing material; Solar cell module.

2. the optical path adjustment member includes a light reflecting member having a light reflecting surface, When the side opposite to the first side in the second direction is defined as the second side in the second direction, the light reflecting surface faces between the first side in the first direction and the second side in the second direction. The solar cell module according to claim 1 .

3. the first cell has a first positive terminal and a first negative terminal; the second cell is electrically isolated from the first cell and has a second positive terminal and a second negative terminal; The solar cell module according to claim 1 or 2.

4. a direction orthogonal to the first direction and the second direction is defined as a third direction, the solar cell elements are arranged to be spaced apart in the second direction and the third direction, the optical path adjustment member fills a gap between the second cells of the solar cell elements adjacent to each other in the second direction and the third direction; The solar cell module according to claim 1 or 2.

5. When a direction orthogonal to the first direction and the second direction is defined as a third direction, the solar cell elements are arranged side by side at least in the third direction, wiring extending in the third direction and connecting the first cells of the plurality of solar cell elements arranged in the third direction; The wiring is formed at least at an end portion of the solar cell element on a first side in the second direction. The solar cell module according to claim 1 or 2.

6. a thickness of the optical path adjustment member in the first direction is equal to a thickness of the second cell in the first direction; The solar cell module according to claim 1 or 2.

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