Solar cell module

Abstract

Provided is a solar cell module (1) in which a plurality of solar cells are sandwiched between a light-receiving-side protective plate (2) and a back-side protective plate (3) that face each other with a sealing material (4) interposed therebetween, wherein the back-side protective plate (3) has a wiring extraction hole (30) that penetrates in the thickness direction, a band-shaped extraction wiring (5) for extracting current to the outside of the module (1) is connected to the plurality of solar cells, the extraction wiring (5) is extracted to the outside of the module (1) through the wiring extraction hole (30), and the extraction wiring (5) has an expansion / contraction part (53) in which the expansion / contraction rate in the extension direction is set to be greater than that of other portions.

Description

Solar cell module Cross-reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2024-222323, and is incorporated by reference into the description of this application.

[0002] The present invention relates to a solar cell module formed by encapsulating a plurality of solar cells.

[0003] Conventionally, a solar cell module formed by attaching a terminal box to a solar cell panel formed by laminating a glass substrate, a sealing sheet, a solar cell string, a sealing sheet, and a back sheet in this order is widely known. In such a solar cell module, a part of the extraction wiring is encapsulated together with the solar cell string in the solar cell panel, and the extraction wiring extends from the inside of the solar cell panel through a through hole formed in the back sheet for extraction to an external terminal box. Also, for the purpose of improving the power generation efficiency of the solar cell module, there is a tendency to increase the size of the solar cells in the module and the module size. Then, since the current value increases, the strip-shaped extraction wiring for extracting the generated current out of the module becomes longer, and the stress applied to the extraction wiring increases. In response to this, in a module structure provided with a plurality of solar cells cut into a small area to suppress the current value, an extraction wiring with a smaller thickness can be used as the current value becomes smaller. Here, the conventional extraction wiring had a fold as shown in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2022-102585

[0005] However, when the thickness of the extraction wiring becomes small, when a fold like that in Patent Document 1 is made, for example, when receiving pressure in the lamination process during manufacturing, the risk of disconnection at the bent portion of the extraction wiring may increase. Especially in the lamination process, it is heated to soften the sealing material and then cooled, so the extraction wiring expands and contracts thermally. It is also necessary to consider that stress is applied to the bent portion due to this thermal expansion and contraction. Also, the conventional extraction wiring may break and be damaged when used outdoors for a long time, and there has been a desire to prevent such damage.

[0006] The present invention aims to provide a solar cell module in which the output wiring is less prone to breakage.

[0007] The solar cell module of the present invention comprises a light-receiving protective plate and a back protective plate facing each other, and a plurality of solar cells sandwiched between the light-receiving protective plate and the back protective plate with a sealing material in between, wherein the back protective plate has wiring outlet holes penetrating in the thickness direction, and a plurality of strip-shaped outlet wirings for extracting current to the outside of the module are connected to the plurality of solar cells, the plurality of outlet wirings extend outside the module through the wiring outlet holes, and each of the plurality of outlet wirings has an expandable portion set to have a larger expansion / contraction ratio in the extension direction than other parts.

[0008] In the solar cell module, the expandable portion may have multiple corrugated sections in which the solid conductive material is wavy in the thickness direction.

[0009] In the solar cell module, the expandable portion may be a mesh-like portion made of a conductive material, or a portion in which multiple through holes penetrating in the thickness direction or multiple notches provided in the thickness direction are formed.

[0010] In the solar cell module, the expandable portion is sandwiched between the light-receiving protective plate and the back protective plate, and may be positioned around the wiring outlet hole or inside the wiring outlet hole.

[0011] Figure 1A is a schematic cross-sectional view of a solar cell module according to this embodiment. Figure 1B is a schematic cross-sectional view of a solar cell module according to this embodiment before the lamination process. Figure 1C is a schematic cross-sectional view of a solar cell module according to this embodiment immediately after the lamination process. Figure 2 is a schematic cross-sectional view of a modified solar cell module. Figure 3A is a schematic diagram of an expandable portion composed of a mesh portion of a modified solar cell module. Figure 3B is a schematic diagram of an expandable portion with through holes formed therein. Figure 3C is a schematic diagram of an expandable portion with notches formed therein.

[0012] The embodiments of the present invention will be described below with reference to Figures 1A to 3C.

[0013] As shown in Figure 1A, the solar cell module 1 is plate-shaped. Furthermore, as shown in Figure 1B, the solar cell module 1 consists of multiple solar cells (not shown) sandwiched between opposing light-receiving protective plates 2 and back protective plates 3 via a sealing material 4, and after a lamination process, it is an integrated solar cell module as shown in Figure 1C.

[0014] In other words, the solar cell module 1 comprises a light-receiving protective plate 2, a back protective plate 3, a sealing material 4, and a plurality of solar cells. The solar cell module 1 in this embodiment is a single-sided light-receiving type. In Figures 1A to 1C, the light-receiving protective plate 2 is shown at the bottom and the back protective plate 3 is shown at the top. The solar cell module 1 also includes output wiring 5 connected to the plurality of solar cells.

[0015] The back protective plate 3 is a plate member that protects the solar cell from the back side (opposite the light-receiving side). The back protective plate 3 is, for example, a glass plate. Furthermore, the back protective plate 3 has wiring outlet holes 30 that penetrate in the thickness direction. In this embodiment, the back protective plate 3 is provided with multiple wiring outlet holes 30, but it may also be provided with only one wiring outlet hole 30. The wiring outlet hole 30 is a round hole, but it may be of other shapes.

[0016] The light-receiving protective plate 2 is a plate member that protects the solar cell from the light-receiving side. Furthermore, the light-receiving protective plate 2 is a plate made of a light-transmitting material, such as a glass plate, in order to allow sunlight for power generation to reach the solar cell.

[0017] Each of the multiple solar cells generates electricity upon receiving light. These multiple solar cells are sandwiched between a light-receiving protective plate 2 and a back-side protective plate 3 via a sealing material 4. In this embodiment, multiple solar cell strings, each consisting of two or more solar cells connected in series, are provided on the solar cell module 1, and current is extracted from each solar cell string via extraction wiring 5. That is, current is extracted from multiple finger electrodes provided on the solar cell via busbar electrodes and then through extraction wiring 5. In this embodiment, each solar cell is a solar cell cut to a small area in order to suppress the current value. Specifically, each solar cell corresponds to a small area such as 1 / 2 of the cross-sectional area of ​​a full-size semiconductor wafer cut from a semiconductor ingot, which is the raw material. However, the configuration (shape) of each solar cell is not limited to this.

[0018] The sealing material 4 is a component for sealing multiple solar cells. The sealing material 4 is also layered on both the light-receiving side and the back side of the multiple solar cells, for example. Furthermore, the sealing material 4 softens during the heating process of the lamination, wrapping around and covering the end faces (outer periphery) of the multiple solar cells. The sealing material 4 is, for example, a resin layer.

[0019] In this embodiment, the sealing material 4 includes a back sealing material 40 provided on the light-receiving side of the back protective plate 3, and a light-receiving side sealing material 41 provided on the back side of the light-receiving side protective plate 2. The sealing material 4 also includes a small piece sealing material 42 provided between the back sealing material 40 and the light-receiving side sealing material 41 at a position that overlaps with the area around the wiring outlet hole 30 of the back protective plate 3 when viewed from the thickness direction of the sealing material 4. The sealing materials 40, 41, and 42 are sheets made of a light-transmitting thermoplastic resin such as ethylene / vinyl acetate copolymer (EVA). In this embodiment, the sealing materials 40, 41, and 42 are formed from the same material, but they may be formed from different materials. The sealing materials 40, 41, and 42 are integrated as shown in Figure 1C through a lamination process from the state in which each sheet shown in Figure 1B is stacked.

[0020] The output wiring 5 is a strip-shaped wire (see Figure 1A). The output wiring 5 is taken out from inside the sealing material 4, which is integrated after the lamination process, through the wiring output hole 30 of the back protective plate 3, and out of the solar cell module 1.

[0021] Two output wires 5, each connected to a plurality of solar cells, enter a single wiring outlet hole 30 from different directions (left and right in Figure 1A). One of these two output wires 51 has a negative polarity, and the other output wire 52 has a positive polarity. These two output wires 5 are spaced apart when viewed from the side. As shown in Figures 1B and 1C, the two output wires 5 are fixed in place by guide pieces 8 placed on top of the back protective plate 3 to prevent misalignment during the lamination process. Specifically, the two output wires 5 are guided by being inserted through two through holes provided in the guide piece 8. The guide piece 8 is made of, for example, fluororesin.

[0022] The output wiring 5 has an expandable section 53 whose expansion and contraction ratio in the extension direction is set to be larger than that of other parts (see Figure 1A). In this configuration, the stress generated by thermal expansion and contraction in the output wiring 5 due to heating and cooling during the lamination process in the manufacturing of the solar cell module 1, and repeated high and low temperature conditions outdoors throughout the day, can be absorbed by the expansion and contraction of the expandable section 53, and since it does not affect other parts (parts other than the expandable section 53), the output wiring 5 is less likely to break.

[0023] In this embodiment, the expandable portion 53 has multiple wave portions 54 formed by a solid conductive material that undulates in the thickness direction. That is, the expandable portion 53 has multiple wave portions 54 that are curved without corners (bent portions) when viewed from the side. Since the wave portions 54 do not have corners, stress concentration is less likely to occur. Also, the wave portions 54 are approximately arc-shaped. With this configuration, the expandable portion 53 of the extraction wiring 5 can be formed by bending alone. The expandable portion 53 may also be formed in a bellows shape, that is, having multiple bent portions.

[0024] The output wiring 5 is made of a solid conductive material throughout its entire length in the direction of extension. Furthermore, the output wiring 5 is, for example, a copper foil that has been solder-plated. Specifically, the output wiring 5 is constructed by plating the front and back surfaces of a copper foil with a thickness of 200 μm to 250 μm with a solder layer 25 μm thick.

[0025] The terminal box 7 is a box-shaped structure having a terminal block for connecting the output wiring 5 and the output cable for power extraction. In this embodiment, the terminal box 7 is provided so as to cover the wiring output hole 30 of the back protective plate 3 from the outside of the solar cell module 1. The terminal box 7 is placed outside the back protective plate 3 after the lamination process and after the guide piece 8 shown in Figure 1C has been removed. Two output wirings 51 and 52 are arranged inside the terminal box 7 (see Figure 1A).

[0026] In this embodiment, the expandable portion 53 is sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and is positioned inside the wiring outlet hole 30 of the back protective plate 3. Therefore, the expandable portion 53 can absorb the stress generated inside the wiring outlet hole 30, where bending is performed to bring the wiring 5 out of the module 1, and stress due to thermal expansion and contraction tends to be large.

[0027] Specifically, the output wiring 5 is sandwiched between the light-receiving protective plate 2 and the back protective plate 3 and includes an expandable portion 53 located inside the wiring output hole 30 of the back protective plate 3, a first non-expandable portion 55 sandwiched between the light-receiving protective plate 2 and the back protective plate 3 and located around the wiring output hole 30 of the back protective plate 3, and a second non-expandable portion 56 located inside the terminal box 7.

[0028] As shown in Figure 2, the expandable portion 53 may be sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and positioned around the wiring outlet hole 30 of the back protective plate 3. That is, the expandable portion 53 may be located between the light-receiving protective plate 2 and the back protective plate 3, and in the vicinity of the wiring outlet hole 30. Even in this configuration, similar to the configuration in which the expandable portion 53 is sandwiched between the light-receiving protective plate 2 and the back protective plate 3 and positioned inside the wiring outlet hole 30 of the back protective plate 3, the bending required to bring the wiring 5 out of the module 1 occurs, and the expandable portion 53 can absorb the stress generated near the wiring outlet hole 30, where stress due to thermal expansion and contraction tends to be large.

[0029] Specifically, this output wiring 5 is sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and may include an expandable portion 53 positioned around the wiring output hole 30 of the back protective plate 3, a first non-expandable portion 55 positioned inside the wiring output hole 30, and a second non-expandable portion 56 positioned inside the terminal box 7.

[0030] The solar cell module of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0031] In the above embodiment, the expandable portion 53 is located only in the area sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and inside the wiring outlet hole 30 of the back protective plate 3, or it is located only in the area sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and around the wiring outlet hole 30 of the back protective plate 3. However, the expandable portion 53 only needs to be located in at least one place within the internal space of the wiring outlet hole 30, the internal space of the terminal box 7, and the area sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and away from the wiring outlet hole 30 of the back protective plate 3.

[0032] In the above embodiment, the expandable portion 53 had a plurality of corrugated portions 54 made of a solid conductive material that undulates in the thickness direction, but it does not have to have corrugated portions 54. For example, the expandable portion 53 may be made of a hollow conductive material. Specifically, the expandable portion 53 may be a mesh-like portion made of a conductive material, as shown in Figure 3A. Alternatively, as shown in Figure 3B, it may be a portion in which a plurality of through holes extending in the thickness direction are formed. Alternatively, as shown in Figure 3C, it may be a portion in which a plurality of notches provided in the thickness direction are formed. In such cases, the expandable portion 53 of the extraction wiring 5 can be made into a flat shape (a shape that does not undulate). In addition to the corrugated portions 54, the expandable portion 53 may also have a mesh-like portion made of a conductive material, etc. Furthermore, the expandable portion 53 may be a mesh-like portion, etc., as well as a portion that has a corrugated shape.

[0033] Furthermore, the two output wires 5 that enter into a single wiring outlet hole 30 may intersect within the space provided by the wiring outlet hole 30. Specifically, the two output wires 5 may not be parallel in a side view, but may intersect at an angle. More specifically, in a side view, one of the two output wires 5, output wire 51, may be positioned towards the front, and the other output wire 52 may be positioned towards the back, so that they intersect in an X shape. Each of these output wires 5 curves and changes direction as it is taken out from the inside to the outside of the solar cell module 1, and the angle of this change is obtuse. In addition, in this configuration, the two output wires 5 are positioned offset in a direction along the plane in a plan view.

[0034] In this configuration, the two output wires 5 can be routed outside the module while curved and crossing each other, and each output wire 5 can be positioned without bending (without folding back to create a sharp bend). For example, during the lamination process when manufacturing the solar cell module 1, even if the output wires 5 are subjected to pressure from the softened sealing material 4, the pressure is less likely to concentrate, making it less likely for the output wires 5 to break.

[0035] Furthermore, the internal space of the wiring outlet hole 30 is sized to allow for some degree of movement of the two outlet wires 5. Therefore, during the lamination process, the outlet wires 5 are less likely to be pressed against the wall surface defining the internal space of the wiring outlet hole 30 and are less likely to be damaged.

[0036] In a configuration where two output wires 5, each inserted into a single wiring outlet hole 30, intersect within the space of the wiring outlet hole 30, an insulating portion may be provided to prevent electrical conductivity between the two output wires 5. In this configuration, the insulating portion is located between the two output wires 5, specifically at the point where they intersect. Specifically, the insulating portion is positioned at least between the front output wire 51 and the back output wire 52 at the point where the two output wires 5 intersect. In this configuration, because the insulating portion is located between the front output wire 51 and the back output wire 52 at the point where the two output wires 5 intersect, it is possible to prevent electrical conductivity between the two output wires 5.

[0037] This insulating portion may be composed of, for example, a resin filled into the space of the wiring outlet hole 30. This resin is formed when the sealing material 4 (small piece sealing material 42), softened by heating during the lamination process in the manufacturing of the solar cell module 1, protrudes into the space of the wiring outlet hole 30. This resin may also be filled into the space of the wiring outlet hole 30 after the lamination process, and may be, for example, a silicone resin. In this configuration, the filling resin in the space of the wiring outlet hole 30 can also serve as an insulating portion that prevents electrical conductivity between the two intersecting outlet wires 5. This insulating portion may also be composed of an insulating sheet.

[0038] Furthermore, the two output wires 5 may intersect not only within the space provided by the wiring output holes 30 of the rear protective plate 3, but also within the internal space of the terminal box 7. In this configuration, an insulating portion is interposed between the two output wires 5 within the terminal box 7 at the point where the two output wires 5 intersect. This insulating portion is an insulating sheet sandwiched between the front output wire 51 and the rear output wire 52 at the point where the two output wires 5 intersect within the internal space of the terminal box 7. In this configuration, the filling resin inside the terminal box 7 can also serve as an insulating portion that prevents electrical conductivity between the two intersecting output wires 5. Furthermore, the insulating portion may be composed of resin filled into the internal space of the terminal box 7.

[0039] In the above embodiment, the insulating part was a resin that filled the space or an insulating sheet, but it may also be an insulating tape that is wrapped around the intersection of the two output wires 5.

[0040] Based on the above, the present invention provides a solar cell module in which the output wiring is less prone to breakage.

[0041] The solar cell module of the present invention comprises a light-receiving protective plate and a back protective plate facing each other, and a plurality of solar cells sandwiched between the light-receiving protective plate and the back protective plate with a sealing material in between, wherein the back protective plate has wiring outlet holes penetrating in the thickness direction, and a plurality of strip-shaped outlet wirings for extracting current to the outside of the module are connected to the plurality of solar cells, the plurality of outlet wirings extend outside the module through the wiring outlet holes, and each of the plurality of outlet wirings has an expandable portion set to have a larger expansion / contraction ratio in the extension direction than other parts.

[0042] With this configuration, the stress generated by thermal expansion and contraction in the output wiring due to heating and cooling during the lamination process in the manufacturing of the solar cell module, and repeated high and low temperature conditions outdoors throughout the day, can be absorbed by the expansion and contraction section, making the output wiring less prone to breakage.

[0043] In the solar cell module, the expandable portion may have multiple corrugated sections in which the solid conductive material is wavy in the thickness direction.

[0044] According to such a configuration, the expansion and contraction portion of the extraction wiring can be formed only by bending.

[0045] In the solar cell module, the expansion and contraction portion may be a net-like portion made of a conductive material, or a portion in which a plurality of through holes penetrating in the thickness direction or a plurality of cutouts provided in the thickness direction are formed.

[0046] According to such a configuration, the expansion and contraction portion of the extraction wiring can be formed into a flat shape.

[0047] In the solar cell module, the expansion and contraction portion may be sandwiched between the light-receiving side protection plate and the back side protection plate, and may be disposed around or inside the wiring extraction hole.

[0048] According to such a configuration, in the vicinity of the wiring extraction hole or inside the wiring extraction hole where the extraction wiring is bent for being taken out of the module, the expansion and contraction portion can absorb the generated stress due to thermal expansion and contraction.

[0049] 1... solar cell module, 2... light-receiving side protection plate, 3... back side protection plate, 4... sealing material, 5... extraction wiring, 7... terminal box, 8... guide piece, 30... wiring extraction hole, 40... back side sealing material, 41... light-receiving side sealing material, 42... small piece sealing material, 51, 52... extraction wiring, 53... expansion and contraction portion, 54... wave portion, 55... first non-expansion and contraction portion, 56... second non-expansion and contraction portion

Claims

1. A solar cell module comprising a light-receiving protective plate and a back protective plate facing each other, and a plurality of solar cells sandwiched between the light-receiving protective plate and the back protective plate with a sealing material in between, wherein the back protective plate has wiring outlet holes penetrating in the thickness direction, a plurality of strip-shaped outlet wirings for extracting current to the outside of the module are connected to the plurality of solar cells, the plurality of outlet wirings extend outside the module through the wiring outlet holes, and each of the plurality of outlet wirings has an expandable portion whose expansion and contraction ratio in the extension direction is set to be greater than that of other parts.

2. The solar cell module according to claim 1, wherein the expandable portion has a plurality of corrugated portions in which a solid conductive material is wavy in the thickness direction.

3. The solar cell module according to claim 1, wherein the expandable portion is a mesh portion made of a conductive material, or a portion in which a plurality of through holes penetrating in the thickness direction or a plurality of notches provided in the thickness direction are formed.

4. The solar cell module according to any one of claims 1 to 3, wherein the expandable portion is sandwiched between the light-receiving protective plate and the back protective plate and is positioned around the wiring outlet hole or inside the wiring outlet hole.

Images