Solar Cell Module

Abstract

To provide a solar cell module with a high degree of freedom in its planar shape.SOLUTION: A solar cell module 1 comprises a plurality of solar cell strings 11, 12 each of which has a plurality of solar cells 13 connected in a row in a first direction with their ends overlapping on each other, and which are arranged in a line in a second direction intersecting the first direction. At least one of the solar cell strings 11 differs from at least one of the solar cell strings 12 in overlapping length of the solar cells 13 in the first direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a solar cell module. [Background technology]

[0002] When arranging a large number of solar cells vertically and horizontally to form a solar cell module with a large area, a configuration is adopted in which multiple solar cells, each of which is made up of multiple solar cells arranged in a row in a first direction and connected together, are arranged in a second direction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2018 / 003563 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a solar cell module is formed in a square shape in a plan view. For this reason, the same solar cell strings are used to form one solar cell module. However, when a solar cell module is mounted on various objects such as an automobile, it is desirable to be able to freely design the planar shape of the solar cell module according to the shape of the usable part of the object. Although it is possible to arrange the solar cell strings only in the square area in the center of the solar cell module, this reduces the area in which the incident light can be used, resulting in a low photoelectric conversion efficiency per area when viewed as a whole module.

[0005] By arranging solar cell strings of different lengths, the effective area can be increased and the photoelectric conversion efficiency can be improved even if the planar shape of the solar cell module is not rectangular. However, if the number of solar cells is varied to change the length of the solar cell string, the number of solar cells connected in series with other solar cell strings will differ, resulting in an imbalance in the output voltage of the solar cell string. In addition, when the length of the solar cell string is adjusted according to the number of solar cells, the length of one solar cell becomes the smallest unit, resulting in an area at the end of the solar cell module where solar cells cannot be placed.

[0006] In view of the above circumstances, an object of the present invention is to provide a solar cell module having a high degree of freedom in terms of its planar shape. [Means for solving the problem]

[0007] A solar cell module according to one embodiment of the present invention comprises a plurality of solar cell strings, each of which has a plurality of solar cell cells connected in a row in a first direction so that their ends overlap each other, and which are arranged in a row in a second direction intersecting the first direction, and at least one of the solar cell strings has a different overlap length in the first direction between the solar cell cells and at least one other of the solar cell strings.

[0008] In the solar cell module according to one aspect of the present invention, the number of solar cells in all of the solar cell strings may be equal.

[0009] In a solar cell module according to one embodiment of the present invention, the overlap length between the solar cell cells of the solar cell string at the second direction end may be greater than the overlap length between the solar cell cells of the solar cell string at the second direction central portion.

[0010] In the solar cell module according to the aspect of the present invention, the solar cell may have a rectangular planar shape.

[0011] In the solar cell module according to one aspect of the present invention, the solar cell may have an electrode only on a back surface.

[0012] In a solar cell module according to one aspect of the present invention, the solar cell of the solar cell string having a longer overlap length than the other solar cell strings may have a larger output current per unit area than the solar cell cells of the other solar cell strings. Effect of the Invention

[0013] The solar cell module according to the present invention has a high degree of freedom in terms of its planar shape. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic plan view of a solar cell module according to one embodiment of the present invention; [Diagram 2] 2 is a schematic cross-sectional view of the solar cell module of FIG. 1 taken along line AA. [Diagram 3] 2 is a schematic cross-sectional view of the solar cell module of FIG. 1 taken along line BB. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For convenience, hatching and component symbols may be omitted. In such cases, other drawings shall be referred to. Furthermore, the dimensions of various components in the drawings have been adjusted for ease of viewing.

[0016] Figures 1 to 3 show a solar cell module 1 according to a first embodiment of the present invention. Figure 1 is a schematic plan view of the solar cell module 1, Figure 2 is a schematic cross-sectional view of the solar cell module 1 taken along line AA, and Figure 3 is a schematic cross-sectional view of the solar cell module 1 taken along line BB.

[0017] The solar cell module 1 includes a plurality of solar cell strings (first solar cell strings 11 at both ends and a plurality of second solar cell strings 12 on the inside), a front-side protective member 20 arranged on the front (incident surface) side of the solar cell strings 11, 12, a back-side protective member 30 arranged on the back side of the solar cell strings 11, 12, and a sealing material 40 filled in a gap between the front-side protective member 20 and the back-side protective member 30. The solar cell module 1 further includes wiring material (not shown) that connects the plurality of solar cell strings 11, 12.

[0018] The solar cell module 1 can have a shape other than a rectangle in plan view. Specifically, the solar cell module 1 of this embodiment has an octagonal shape with the corners of a rectangle chamfered in plan view.

[0019] Each of the solar cell strings 11 and 12 has a plurality of solar cell 13 connected in a row in a first direction with their ends overlapping. Specifically, one end of each solar cell 13 in the first direction is overlapped on the back side of the other end of the adjacent solar cell 13 in the first direction. In other words, the solar cell strings 11 and 12 have a so-called shingling structure. All of the solar cell 13 in the solar cell strings 11 and 12 may be the same.

[0020] The multiple solar cell strings 11, 12 are arranged side by side in a second direction intersecting with the first direction. In the figure, the spacing between the solar cell strings 11, 12 and the margins on the periphery of the solar cell module 1 are shown large for ease of understanding, but in reality, it is preferable that the solar cell strings 11, 12 are arranged over substantially the entire surface of the solar cell module 1 with the spacing between them and the margins on the periphery minimized.

[0021] It is preferable that all the solar cells 13 are electrically connected in series in each of the solar cell strings 11 and 12. This allows the configuration of the solar cell strings 11 and 12 to be simplified.

[0022] It is preferable that the number of solar cells 13 in the solar cell strings 11, 12 is equal. As a result, when the solar cell strings 11, 12 are formed by connecting the same solar cell cells 13 in series, the output voltages of the solar cell strings 11, 12 are constant, so that when a plurality of solar cell strings 11, 12 are electrically connected, the outputs of all the solar cell strings 11, 12 can be extracted without waste.

[0023] The length in the first direction of the first solar cell string 11 at the end in the second direction is smaller than the length in the first direction of the second solar cell string 12 at the center in the second direction in order to match the octagonal planar shape of the solar cell module 1. For this reason, the overlap length in the first direction between the solar cells 13 of the first solar cell string 11 is larger than the overlap length in the first direction between the solar cells 13 of the second solar cell string 12.

[0024] It is preferable that the overlap length in the first direction between two adjacent solar cells 13 in each of the solar cell strings 11, 12 is substantially constant. This makes the output of each solar cell 13 substantially equal, and therefore the multiple solar cells 13 can be used evenly.

[0025] The lower limit of the ratio of the maximum value to the minimum value of the average overlap length between the solar cells 13 of the solar cell strings 11 and 12 (the average value of the overlap length in the first direction between two adjacent solar cells 13 in each of the solar cell strings 11 and 12) is preferably 105%, more preferably 110%. On the other hand, the upper limit of the ratio of the maximum value to the minimum value of the average overlap length between the solar cells 13 of the solar cell strings 11 and 12 is preferably 500%, more preferably 300%. By setting the ratio of the maximum value to the minimum value of the average overlap length between the solar cells 3 of the solar cell strings 11 and 12 to the lower limit or more, a clear difference can be made between the length of the first solar cell string 11 and the length of the second solar cell string 12. In addition, by setting the ratio of the maximum value to the minimum value of the average overlap length between the solar cells 13 of the solar cell strings 11 and 12 to the upper limit or less, the ineffective area of ​​each solar cell 13 (area shaded by adjacent solar cell 13) can be reduced, and an increase in the device cost per output can be suppressed.

[0026] Specifically, the average overlap length between the solar cells 13 of the solar cell strings 11, 12 is preferably, for example, 1 mm to 30 mm, and more preferably 2 mm to 20 mm, although it depends on the size of the solar cell 13. This makes it possible to form the solar cell strings 11, 12 without difficulty and to effectively utilize the photoelectric conversion capacity of each solar cell 13.

[0027] The solar cells 13 are connected by a conductive connecting member called an interconnector inside the solar cell strings 11 and 12. The length of the interconnector may be adjusted according to the average overlap length of the solar cells 13, but when the difference in the average overlap length of the solar cells 13 between the solar cell strings 11 and 12 is small, the interconnector connecting the solar cells 13 may be common.

[0028] When forming the solar cell strings 11, 12, the arrangement of multiple solar cell 13 may be performed by using a jig created to achieve the desired overlap length to position the solar cell 13, or by using a device that can arbitrarily position the solar cell 13 by computer control.

[0029] The solar cell 13 is not particularly limited, but is preferably a back electrode type solar cell having an electrode only on the back surface. By using a back electrode type solar cell that does not have an electrode that blocks light on the incident surface side as the solar cell 13, a relatively high photoelectric conversion efficiency can be achieved. In addition, by adopting a back electrode type solar cell, the color of the solar cell module 1 when viewed from the front surface side becomes black overall, and the aesthetic appearance of the solar cell module 1 can be improved.

[0030] Solar cell 13 has a connection electrode to which an interconnector is connected for electrical connection with adjacent solar cell 13. This connection electrode is preferably disposed in an area on the back surface of solar cell 13 that is slightly closer to the center in the first direction than an area that may be disposed on the side that is disposed on the front side of the adjacent solar cell 13. This makes it possible to suppress a decrease in the connectivity of the interconnector due to an increase in the average overlap length between solar cells 13.

[0031] The planar shape of the solar cell 13 is preferably rectangular. By making the solar cell 13 rectangular, the overlapping region of the solar cell 13 can be made into a small strip shape with a constant width in the first direction, so that the area ratio of the effective region of the solar cell 13 (the region where the surface is not covered by adjacent solar cell 13 and where light actually enters and contributes to photoelectric conversion) can be increased. This allows the manufacturing cost per output of the solar cell strings 11, 12 and thus the solar cell module 1 to be reduced.

[0032] It is preferable that the solar cells of the solar cell string 11 having a larger overlap length than the other solar cell strings 12 have a larger output current per unit area than the solar cells of the other solar cell strings. This makes it possible to reduce the difference in output between the first solar cell string 11 and the second solar cell string 12, so that the output of all the solar cell strings 11, 12 can be extracted without waste. For this reason, it is desirable to make the outputs of all the solar cell strings 11, 12 as equal as possible.

[0033] For this reason, it is preferable to measure the short-circuit current Isc of each solar cell 13 and sort the solar cells 13 used in the first solar cell string 11 and the solar cells 13 used in the second solar cell string 12 so as to reduce the output difference between the solar cell strings 11 and 12. Specifically, the solar cells 13 can be sorted using, for example, an index such as a value obtained by dividing the short-circuit current Isc by a planned effective area in the solar cell strings 11 and 12 that generate the short-circuit current Isc, or a value obtained by multiplying the short-circuit current Isc by a planned effective area ratio.

[0034] The front protective member 20 protects the solar cell 13 by covering the solar cell strings 11, 12, i.e., the surfaces of the solar cell 13, via the sealing material 40. The front protective member 20 can be formed from a plate-like or sheet-like material, and preferably has excellent light transmittance and weather resistance. Specifically, examples of the material for the front protective member 20 include transparent resins such as acrylic resins and polycarbonate resins, and glass. Furthermore, the surface of the front protective member 20 may be processed to have an uneven shape or may be coated with an anti-reflective coating layer in order to suppress light reflection.

[0035] The backside protective member 30 covers the backside of the solar cell strings 11, 12 via the sealing material 40 to protect the solar cell 13. The backside protective member 30 can be formed from a plate-like or sheet-like material, similar to the frontside protective member 20, and preferably has excellent water impermeability. Specifically, examples of the backside protective member 30 include resin films such as polyethylene terephthalate (PET), polyethylene (PE), olefin resin, fluorine-containing resin, and silicone resin, laminates of the resin films and metal foils such as aluminum foil, transparent resins such as acrylic resins and polycarbonate resins, and glass.

[0036] The sealing material 40 seals and protects the solar cell strings 11, 12, i.e., the solar cells 13, and in particular prevents moisture from coming into contact with the solar cells 13. For this reason, the sealing material 40 is interposed between the light-receiving surface of the solar cell 13 and the front-side protection member 20, and between the back surface of the solar cell 13 and the back-side protection member 30.

[0037] The sealing material 40 bonds the solar cell strings 11, 12 to the front protection member 20 and the back protection member 30, and also protects the solar cells 13 by eliminating gaps around the solar cell strings 11, 12. For this reason, the sealing material 40 is preferably a thermoplastic resin having translucency, such as ethylene / vinyl acetate copolymer (EVA), ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), acrylic resin, urethane resin, or silicone resin.

[0038] As described above, the solar cell module 1 includes the first solar cell string 11 and the second solar cell string 12 in which the overlap lengths in the first direction between the solar cells 13 are different, and thus has a planar shape with rounded corners when viewed from above, while the ineffective area where the solar cells 13 are not arranged is small, resulting in excellent photoelectric conversion efficiency per area.

[0039] Furthermore, the design of the solar cell module 1 can be easily changed by changing the overlap length in the first direction of the multiple solar cells 13 of the solar cell strings 11 and 12 in accordance with the planar shape of the solar cell module 1. In other words, the solar cell module 1 has a high degree of freedom in designing the planar shape.

[0040] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various changes and modifications are possible.

[0041] The solar cell module according to the present invention may have any planar shape. Therefore, in the solar cell module according to the present invention, the number of solar cell strings having a different overlap length of the solar cell from other solar cell strings is not limited, and three or more types of solar cell strings having different overlap lengths of the solar cell may be present. Furthermore, in order to form a solar cell module having a planar shape with a narrowed central portion in the first direction, a solar cell string having a large overlap length of the solar cell may be arranged in the central portion in the second direction. [Explanation of symbols]

[0042] 1. Solar cell module 11,12 Solar cell string 13 Solar Cell 20 Surface protection material 30 Back protection material 40 Encapsulating material

Claims

1. a plurality of solar cell strings each having a plurality of solar cell cells connected in a row in a first direction so that their ends overlap each other, and arranged side by side in a second direction intersecting the first direction; At least one of the solar cell strings has a different overlap length between the solar cells in the first direction from at least one other of the solar cell strings; A solar cell module, wherein the solar cell of the solar cell string having the overlap length greater than those of the other solar cell strings has a larger output current per unit area than the solar cell of the other solar cell strings.

2. The solar cell module according to claim 1 , wherein the number of solar cells in all of the solar cell strings is equal.

3. The solar cell module according to claim 1 or 2, wherein the overlap length between the solar cells of the solar cell string at the end in the second direction is greater than the overlap length between the solar cells of the solar cell string at the center in the second direction.

4. The solar cell module according to claim 1 , wherein the solar cell has a rectangular planar shape.

5. The solar cell module according to claim 1 , wherein the solar cell has an electrode only on a back surface thereof.

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