JP2021111736A - Solar cell module - Google Patents

Abstract

To provide a reliable solar cell module.SOLUTION: A solar cell module 1 according to the present invention comprises: a plurality of solar cells 10 each including a plurality of connection electrodes 15 and arranged side by side in the first direction; and a plurality of wiring materials 20 connecting between the connection electrodes 15 of the solar cell 10 adjacent to each other in the first direction. The solar cell 10 is arranged such that the end on one side in the first direction is arranged so as to overlap the back side of the end on the other side in the first direction of the adjacent solar cell 10, and includes a cushioning material 17 that supports the wiring material 20 on the back surface of the end on the one side in the first direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a solar cell module.

Some solar cells have a back contact type having electrodes only on the back surface side. In the back contact type solar cell, since the electrode that blocks light is not arranged on the surface side, substantially the entire surface can contribute to photoelectric conversion. As a form of a back-contact type solar cell, a plurality of first electrodes having a first polarity and a plurality of second electrodes having a second polarity are dispersed over the entire substrate in order to reduce current collection resistance. Some of the wiring materials (linear conductors) for connecting the plurality of first electrodes and the plurality of wiring materials for connecting the plurality of second electrodes are provided. When solar cells having a plurality of wiring materials are connected and modularized in this way, the wiring materials are integrated between the adjacent solar cells, that is, the wiring material extending across the adjacent solar cells is provided. It is known that the solar cells are connected to each other by using the cells.

Further, as an embodiment in which a plurality of solar cells are modularized, a single ring structure in which a plurality of solar cells are connected side by side so as to overlap each other in order is known. By overlapping the ends of the solar cells, the ratio of the area of the effective region that actually contributes to the photoelectric conversion to the area of the entire module can be increased. Even in a solar cell module that uses a back-contact type solar cell, the output per area of the module is improved by adopting a single ring structure in which the ends of the solar cell are overlapped so that there is no gap between the solar cells. can do.

Patent Document 1 describes a module in which the ends of solar cells are overlapped and the solar cells are connected by using a first current collecting member and a second current collecting member extending across adjacent solar cells. Has been done. In Patent Document 1, by arranging the insulating material in the area where the adjacent solar cells on the back surface of the solar cell arranged on the front surface side are overlapped, the stress is concentrated in the area where the solar cells are overlapped. A technique for preventing the solar cell from being damaged or the solder for connection from being peeled off is disclosed.

Japanese Patent No. 5430326

With the configuration of Patent Document 1, it is possible to reduce the stress acting on the surfaces of the solar cells facing each other. However, even in the configuration of Patent Document 1, the first current collecting member and the second current collecting member extending across the solar cells are pressed against the edge of the end portion of the solar cell on the back surface side, so that the sun on the back surface side is pressed. The end of the battery cell may be damaged, which causes a decrease in reliability.

An object of the present invention is to provide a highly reliable solar cell module.

The solar cell module according to the present invention has a plurality of connection electrodes, and is located between a plurality of solar cells arranged side by side in the first direction and the connection electrodes of the solar cells adjacent to the first direction. A plurality of wiring materials to be connected are provided, and the solar cell is arranged so that its end on one side in the first direction overlaps the back side of the end on the other side in the first direction of the adjacent solar cell. A cushioning material that supports the wiring material is provided on the back surface of the end portion on one side of the first direction.

In the solar cell module according to the present invention, the cushioning material may be intermittently arranged in a direction perpendicular to the first direction.

In the solar cell module according to the present invention, the cushioning material may have one or more recesses extending in the first direction on the back surface.

In the solar cell module according to the present invention, the depth of the recess may be 7 μm or more and 30 μm or less, and the width of the recess may be 50 μm or more and 200 μm or less.

In the solar cell module according to the present invention, the length of the cushioning material in the direction perpendicular to the first direction may be larger than the length in the first direction.

In the solar cell module according to the present invention, the solar cell further includes a wiring insulating material between the connection electrodes to prevent electrical contact between a portion other than the connection electrodes and the wiring material, and the cushioning material. May be formed of the same material as the wiring insulating material.

In the solar cell module according to the present invention, the solar cell further has a cell insulating material that supports the solar cell adjacent to the back surface of the end on the other side in the first direction, and the first of the cushioning materials. The length in the direction perpendicular to one direction may be longer than the length in the direction perpendicular to the first direction of the cell insulating material.

According to the present invention, it is possible to provide a highly reliable solar cell module.

It is a schematic back view of the solar cell module of this invention. It is a schematic cross-sectional view of the solar cell module of FIG. FIG. 5 is a cross-sectional view taken along the line AA of the solar cell module of FIG. FIG. 3 is a cross-sectional view taken along the line BB of the solar cell module of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, hatching, member codes, etc. may be omitted, but in such cases, other drawings shall be referred to. Further, the dimensions of the various members in the drawings are adjusted for convenience so that they can be easily seen.

FIG. 1 is a schematic back view of the solar cell module 1 according to the embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the solar cell module of FIG. FIG. 3 is a cross-sectional view taken along the line AA of the solar cell module 1. FIG. 4 is a cross-sectional view taken along the line BB of the solar cell module 1.

The solar cell module 1 includes a plurality of solar cell strings 2 extending in the first direction, a front side protective member 3 arranged on the front surface (light receiving surface) side of the solar cell string 2, and a back surface (light receiving surface) of the solar cell string 2. A pair of connections connecting the back side protective member 4 arranged on the side opposite to the side), the sealing material 5 filled in the gap between the front side protective member 3 and the back side protective member 4, and the solar cell string 2. A member 6 is provided.

The solar cell string 2 includes a plurality of solar cells 10 arranged in the first direction, a plurality of wiring materials 20 for electrically connecting the solar cells 10, a plurality of solar cells 10, and a plurality of wiring materials. A resin film 30 that covers the back surface side of the 20 is provided. In the solar cell string 2, each solar cell 10 is arranged so that one end in the first direction overlaps the back surface of the other end of the adjacent solar cell 10. That is, the solar cell string 2 has a single ring structure in which the ends of the plurality of solar cells 10 in the first direction are sequentially stacked.

Each solar cell 10 has a semiconductor substrate 11. A plurality of strip-shaped firsts having a first conductive type and extending in a second direction perpendicular to the first direction in a region on the back surface side of the semiconductor substrate 11 where at least the other solar cells 10 are not arranged on the front surface side. The semiconductor layer 12 and a plurality of strip-shaped second semiconductor layers 13 having a second conductive type and extending in the second direction are alternately arranged in the first direction. Collection electrodes 14 extending in the second direction are arranged on the back surface sides of the first semiconductor layer 12 and the second semiconductor layer 13, respectively. On the back surface side of each collection electrode 14, a plurality of connection electrodes 15 to which the wiring material 20 is connected are arranged at regular intervals. The connection electrodes 15 on the back surface side of the first semiconductor layer 12 and the connection electrodes 15 on the back surface side of the second semiconductor layer 13 are arranged alternately. Wiring insulating materials 16 are arranged in the portions between the connection electrodes 15 on the back surface side of the collection electrode 14. A cushioning material 17 that supports the wiring material 20 is arranged in an end portion of the back surface of the semiconductor substrate 11 on one side in the first direction, that is, a region arranged on the back side of the other solar cell 10, and the semiconductor substrate 11 is provided with a cushioning material 17. A cell insulating material 18 that supports an adjacent solar cell 10 is arranged in an end portion on the other side in the first direction of the back surface, that is, a region arranged on the front side of another solar cell 10. In addition to these configurations, the solar cell 10 may have various components such as an antireflection layer and a passivation layer.

The semiconductor substrate 11 can be formed from crystalline silicon such as single crystal silicon or polycrystalline silicon. The semiconductor substrate 11 is, for example, a p-type semiconductor substrate in which a crystalline silicon material is doped with a p-type dopant. Examples of the p-type dopant include boron (B). Such a semiconductor substrate 11 functions as a photoelectric conversion substrate that absorbs incident light from the surface to generate optical carriers (electrons and holes).

The first semiconductor layer 12 and the second semiconductor layer 13 can be formed of amorphous silicon doped with a dopant that imparts a desired conductive type. Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P).

The collection electrode 14 can be formed by printing and firing a conductive paste such as silver paste.

The connection electrode 15 can be formed by printing and firing a conductive paste such as silver paste. That is, the connection electrode 15 can be formed by locally laminating a similar material on the collection electrode 14.

The wiring insulating material 16 is arranged so as to overlap the wiring material 20 at least in a plan view of the collecting electrode 14 and cover a region where the connecting electrode 15 does not exist. The wiring insulating material 16 can be formed by printing and firing a paste-like insulating material.

The wiring insulating material 16 makes electrical contact between a portion other than the connection electrode 15 and the wiring material 20, more specifically, the wiring material 20 connected to the connection electrode 15 arranged on the back surface side of the first semiconductor layer 12. And the short circuit between the collecting electrode 14 arranged on the back surface side of the second semiconductor layer 13 and the wiring material 20 and the first semiconductor layer connected to the connection electrode 15 arranged on the back surface side of the second semiconductor layer 13. Prevents a short circuit with the collection electrode 14 arranged on the back surface side of the twelve.

The cushioning material 17 supports the wiring material 20 so as not to come into direct contact with the semiconductor substrate 11. As a result, it is possible to prevent the wiring material 20 from being pressed against the edge of the semiconductor substrate 11 in the manufacturing process of the solar cell module 1 to cause cracks or chips in the semiconductor substrate 11.

The cushioning material 17 can be formed by printing and firing a paste-like insulating material. The cushioning material 17 can be formed from the same material as the wiring insulating material 16, and may be formed at the same time as the wiring insulating material 16.

From the viewpoint of preventing cracks and chips in the semiconductor substrate 11, it is desirable that the material of the cushioning material 17 has a smaller elastic modulus than that of the semiconductor substrate 11. As a specific material, it is preferable to use a printable material containing an epoxy resin, urethane resin or the like as a main component. Such a material is also preferable as the wiring insulating material 16 and the cell insulating material 18 described later.

The cushioning material 17 is intermittently arranged in the second direction on the back surface side of the end portion on one side of the first direction of the semiconductor substrate 11, and more specifically, the cushioning material 17 is selectively arranged at a position where the wiring material 20 is arranged. Is preferable. Further, it is preferable that each cushioning material 17 has a sufficient length in the second direction in consideration of the misalignment of the wiring material 20, that is, the length in the second direction is larger than the length in the first direction. .. Specifically, the length of the impact material 109 in the second direction is preferably 2 mm or more and 5 mm or less, and more preferably 3 mm or more and 4 mm or less. The length of the cushioning material 17 in the first direction is preferably smaller than the length in the second direction. As a result, the amount of the material used to form the cushioning material 17 can be reduced while reliably supporting the wiring material 20. Further, the cushioning material 17 may be formed in a plurality of rows in the first direction.

Each cushioning material 17 preferably has one or more recesses 171 extending in the first direction on the back surface. Since each cushioning material 17 has one or more recesses 171 so that the wiring material 20 does not easily slip in the second direction on the cushioning material 17 when forming the solar cell string 2, the wiring material 20 is securely attached to the connecting electrode 15. Can be connected to.

The depth of the recess 171 (the distance between the straight line connecting the peaks of the nearest heights on both sides of the recess 171 of the cushioning material 17 and the deepest portion of the recess 171 in the direction perpendicular to the semiconductor substrate 11) is 7 μm or more and 30 μm or less. It is preferably 10 μm or more and 25 μm or less, more preferably. If the depth of the recess 171 is too small, the wiring material 20 tends to slip in the second direction on the cushioning material 17, so that it may not be easy to fix the wiring material 20 at an appropriate position. On the contrary, if the depth of the recess 171 is too large, the thickness of the cushioning material 17 at the deepest portion of the recess 171 supporting the wiring material 20 becomes small, and the function as the cushioning material may be insufficient. For the width of the recess 171 (distance in the direction parallel to the semiconductor substrate 11 between the peaks at the nearest heights on both sides of the recess 171 of the cushioning material 17), use a wiring material 20 having a circular or elliptical cross section. Assuming, it is preferably 7 times or more and 15 times the depth of the recess 171, specifically 50 μm or more and 200 μm or less. When a plurality of recesses 171 are provided, the pitch of the recesses 171 is preferably 100 μm or more and 500 μm or less. By arranging the recesses 171 in this way, it is possible to effectively prevent the misalignment of the arranged wiring material 20 while allowing the positioning error of the wiring material 20.

The recess 171 can be formed by dividing the cushioning material 17 into a plurality of blocks in the second direction and printing a paste-like insulating material. The paste-like insulating material is printed using a printing mask having a certain thickness, but bleeding occurs in which the insulating material flows so that the portion on the semiconductor substrate 11 side is wider than the opening shape of the mask in cross-sectional view. Therefore, by dividing the cushioning material 17 into a plurality of blocks having a small gap and printing, the blocks are connected by bleeding, and the recess 171 whose height corresponding to the gap between the blocks is relatively small. The cushioning material 17 can be formed.

The cell insulating material 18 is arranged so as to cover at least a part of the collecting electrode 14. The cell insulating material 18 prevents the stacked solar cells 10 from directly contacting the semiconductor substrate 11 or the collecting electrode 14 to cause a short circuit, or to prevent the semiconductor substrate 11 from cracking or chipping.

It is preferable that the cell insulating material 18 is intermittently arranged in the second direction on the back surface side of the end portion of the semiconductor substrate 11 on the other side in the first direction. As a result, the sealing material 5 can be filled in the gap between the cushioning materials 17 and the solar cells 10. Further, the cushioning material 17 may be arranged in a plurality of rows in the first direction. As a result, the connection electrode 15 can be more reliably protected by using a relatively small amount of insulating material. The length of the cell insulating material 18 in the second direction may be about the same as the length in the first direction. As an example, the cell insulating material 18 can be formed in a point shape having a length in the first direction and a length in the second direction having the same degree. Further, the length of the cell insulating material 18 in the second direction may be smaller than the length of the cushioning material 17 in the second direction.

The wiring material 20 connects a plurality of connection electrodes 15 arranged in the first direction in the solar cell 10, and functions as an interconnector for connecting the adjacent solar cells 10. The wiring material 20 and the second semiconductor are arranged so that the adjacent solar cells 10 are oriented in opposite directions, and are connected to the connection electrodes 15 arranged on the back surface side of the first semiconductor layer 12 in each solar cell 10. Each wiring material 20 is arranged across two solar cells so that the wiring material 20 connected to the connection electrode 15 arranged on the back surface side of the layer 13 extends to the solar cell 10 on a side different from that in the first direction. By doing so, a plurality of solar cell 10s can be connected in series.

The wiring material 20 is formed of a material having a small electric resistance, such as a copper wire. Further, the wiring material 20 may be covered with solder for connecting to the collection electrode 14.

When connecting the plurality of wiring materials 20 to the plurality of solar cells 10 in which the ends are overlapped, the resin film 30 holds the plurality of wiring materials 20 in advance at appropriate intervals, and holds the plurality of wiring materials 20 at appropriate intervals. It is possible to integrally position the plurality of solar cells 10 with respect to a plurality of solar cells 10. Further, the resin film 30 is adhered to the solar cell 10 to protect the back surface of the solar cell string 2 before assembling the solar cell module 1.

The resin film 30 preferably has a plurality of openings so as to allow the sealing material 5 to be filled in the gaps between the solar cells 10. As described above, when each wiring material 20 is arranged across the two solar cells, this opening is simultaneously formed by processing for dividing one long conductor to form each wiring material 20. You may.

The front side protective member 3 protects the solar cell 10 by covering the surface of the solar cell string 2, that is, the solar cell 10 via the sealing material 5. The front side protective member 3 can be formed of a plate-shaped or sheet-shaped material, and is preferably excellent in translucency and weather resistance. Specifically, as the material of the front side protective member 3, for example, a transparent resin such as an acrylic resin or a polycarbonate resin, glass, or the like can be mentioned. Further, the surface of the front side protective member 3 may be processed into an uneven shape or coated with an antireflection coating layer in order to suppress the reflection of light.

The back side protective member 4 covers the back surface of the solar cell string 2 via the sealing material 5 to protect the solar cell 10. Like the front side protective member 3, the back side protective member 4 can be formed of a plate-shaped or sheet-shaped material, and is preferably excellent in water-shielding property. Specifically, the back side protective member 4 is a laminate of, for example, a resin film such as polyethylene terephthalate (PET), polyethylene (PE), an olefin resin, a fluorine-containing resin, or a silicone resin, and a metal foil such as aluminum foil. Is preferably used.

The sealing material 5 seals and protects the solar cell string 2, that is, the solar cell 10, the space between the light receiving side surface of the solar cell 10 and the front side protective member 3, and the solar cell 10. It is interposed between the back side surface of the and the back side protective member 4.

The sealing material 5 protects the solar cell 10 by adhering the solar cell string 2, the front side protective member 3 and the back side protective member 4, and eliminating the gap around the solar cell string 2. Therefore, examples of the sealing material 5 include ethylene / vinyl acetate copolymer (EVA), ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate (EVAT), and polyvinyl butyral (PVB). ), Acrylic resin, urethane resin, or a translucent thermoplastic resin such as silicone resin is preferably used.

One connecting member 6 is connected to a wiring material 20 connected to a connecting electrode 15 arranged on the back surface side of the first semiconductor layer 12 of the solar cell 10 at one end of the solar cell string 2, and the other connecting member 6 is connected. 6 The other end of the solar cell string 2 is connected to a wiring material 20 connected to a connection electrode 15 arranged on the back surface side of the second semiconductor layer 13 of the solar cell 10. The connecting member 6 extends outward from between the front side protective member 3 and the back side protective member 4 so as to be connectable to an external circuit of the solar cell module 1.

As described above, in the solar cell module 1 using the solar cell 10 having the buffer material 17 supporting the wiring material 20 on the back surface side of the end portion on one side of the first direction of the semiconductor substrate 11, the wiring material 20 is a semiconductor. Since it is prevented that the semiconductor substrate 11 is cracked or chipped by being pressed against the edge of the substrate 11, it is excellent in reliability and can be provided at a relatively low cost by improving the yield at the time of manufacturing.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and modifications can be made. As an example, in the solar cell module according to the present invention, the semiconductor layer may be formed by diffusing a dopant on a semiconductor substrate. Further, in the solar cell module according to the present invention, the collection electrode and the connection electrode may be formed by laminating metal materials by vapor deposition or the like.

1 Solar cell module 2 Solar cell string 3 Front side protective member 4 Back side protective member 5 Encapsulant 6 Connection member 10 Solar cell 11 Semiconductor substrate 12 First semiconductor layer 13 Second semiconductor layer 14 Collection electrode 15 Connection electrode 16 Wiring insulation 17 Buffer material 18 Cell insulation material 20 Wiring material 30 Resin film 171 Recess

Claims (7)

A plurality of solar cells each having a plurality of connection electrodes and arranged side by side in the first direction,
A plurality of wiring materials connecting the connection electrodes of the solar cell adjacent to the first direction, and
With
The solar cell is
The end on one side in the first direction is arranged so as to overlap the back side of the end on the other side in the first direction of the adjacent solar cell.
A solar cell module having a cushioning material for supporting the wiring material on the back surface of an end portion on one side of the first direction. The solar cell module according to claim 1, wherein the cushioning material is intermittently arranged in a direction perpendicular to the first direction. The solar cell module according to claim 1 or 2, wherein the cushioning material has one or more recesses extending in the first direction on the back surface. The solar cell module according to claim 3, wherein the depth of the recess is 7 μm or more and 30 μm or less, and the width of the recess is 50 μm or more and 200 μm or less. The solar cell module according to any one of claims 1 to 4, wherein the length of the cushioning material in the direction perpendicular to the first direction is larger than the length in the first direction. The solar cell further includes a wiring insulating material between the connecting electrodes to prevent electrical contact between a portion other than the connecting electrodes and the wiring material.
The solar cell module according to any one of claims 1 to 5, wherein the cushioning material is made of the same material as the wiring insulating material. The solar cell further includes a cell insulating material that supports the solar cell adjacent to the back surface of the other end in the first direction.
The solar cell module according to any one of claims 1 to 6, wherein the length of the cushioning material in the direction perpendicular to the first direction is larger than the length of the cell insulating material in the direction perpendicular to the first direction.

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