Solar cell module

Abstract

A solar cell module (1) in which a plurality of solar cells are sandwiched, via a sealing material (4), between a light-receiving side protective plate (3) and a back side protective plate (2) that are opposite of each other, wherein the back side protective plate (2) has wire extraction holes (30) penetrating in the thickness direction, the plurality of solar cells are connected to strip-shaped extraction wires (5) for extracting current to the outside of the module (1), the extraction wires (5) are extracted to the outside of the module (1) through the wire extraction holes (30), two extraction wires (5) connected to the plurality of solar cells are inserted in one of the wire extraction holes (30) from different directions, and the two extraction wires (5) are disposed so as to be offset in a direction along the surface in plan view and intersect each other at an angle in side view.

Description

Solar cell module Cross-reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2024-222322, which is incorporated herein by reference.

[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 and the module size within the module. Then, since the current value increases, the strip-shaped extraction wiring for extracting the generated current outside 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 according to the reduction in the current value. 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 as 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. 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] An object of the present invention is to provide a solar cell module in which the extraction wiring is less likely to be disconnected.

[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 a wiring outlet hole that penetrates in the thickness direction, and a pair of strip-shaped outlet wirings for taking out current from the module are connected to the plurality of solar cells, the pair of outlet wirings extending out of the module through the wiring outlet hole, the pair of outlet wirings connected to the plurality of solar cells entering the wiring outlet hole from different directions, the pair of outlet wirings being offset in a direction along the surface in a plan view and intersecting at an angle in a side view.

[0008] In the solar cell module, an insulating portion may be interposed between the pair of output wirings at the intersection.

[0009] In the solar cell module, a terminal box is provided on the outside of the back protective plate so as to cover the wiring outlet hole, and the insulating portion may be made of resin that fills the space of the wiring outlet hole or the internal space of the terminal box.

[0010] 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 the solar cell module according to this embodiment before the lamination process. Figure 1C is a schematic cross-sectional view of the solar cell module according to this embodiment immediately after the lamination process. Figure 2 is a schematic bottom view of the area around the wiring outlet hole of the solar cell module. Figure 3A is a schematic cross-sectional view of a modified solar cell module. Figure 3B is a schematic cross-sectional view of the modified solar cell module before the lamination process. Figure 3C is a schematic cross-sectional view of the modified solar cell module immediately after the lamination process.

[0011] The embodiments of the present invention will be described below with reference to Figures 1A to 3C.

[0012] 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.

[0013] 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 comprises output wiring 5 connected to the plurality of solar cells. Furthermore, the solar cell module 1 comprises an insulating section 6. The solar cell module 1 also comprises a terminal box 7 provided on the outside of the back protective plate 3 (see Figure 1A).

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] The extraction wiring 5 is a strip-shaped wiring (see Figure 1A). The extraction wiring 5 is extracted from inside the sealing material 4, which is integrated after the lamination process, through the wiring extraction hole 30 of the back protective plate 3 to the outside of the solar cell module 1. The extraction wiring 5 is, for example, a copper foil that has been solder-plated. Specifically, the extraction 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 solder that is 25 μm thick. The elasticity of the extraction wiring 5 is approximately the same at all points in the direction of extension.

[0020] A pair of 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. As shown in Figure 2, the direction in which each of the two output wires 5 enters the wiring outlet hole 30 and the direction in which it exits the wiring outlet hole 30 are the same in a plan view (horizontal direction in Figure 2). Furthermore, these two output wires 5 are offset in a direction along the plane (vertical direction in Figure 2) in a plan view.

[0021] Furthermore, the two output wires 5 intersect at an angle, rather than parallel, in a side view (see Figure 1A). In this embodiment, the two output wires 5 intersect within the space of the wiring outlet hole 30. Specifically, in a side view, one of the two output wires 5, output wire 51, is positioned towards the front, and the other output wire 52 is positioned towards the back, intersecting in an X shape. Also, each output wire 5 curves and changes direction as it is brought out from the inside to the outside of the solar cell module 1, and the angle of this curve is obtuse. The two output wires 5 are fixed in place by guide pieces 8 placed on top of the back protective plate 3, as shown in Figures 1B and 1C, so as not to shift position during the lamination process. Specifically, the two output wires 5 are guided by being inserted into two through holes provided in the guide piece 8. The guide piece 8 is made of, for example, fluororesin. In this embodiment, a pair of output wires 5 enter a single wiring outlet hole 30 from different directions. However, multiple pairs of output wires 5, such as four output wires 5 or six output wires 5, may also enter from different directions.

[0022] In the solar cell module 1 described above, the two output wires 5 can be routed outside the module while being curved and crossed, and each output wire 5 can be arranged without bending (without folding back to create a sharp bend). For example, during the lamination process in the manufacturing of 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.

[0023] In this embodiment, 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.

[0024] 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 (see Figure 1A). In this embodiment, the terminal box 7 is provided so as to cover the wiring output holes 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 5 ​​are arranged inside the terminal box 7 (see Figure 1A).

[0025] The insulating portion 6 is provided to prevent electrical conductivity between the two output wires 5. In this embodiment, the insulating portion 6 is interposed between the two output wires 5 in the portion 53 where the two output wires 5 intersect. Specifically, the insulating portion 6 is positioned at least between the front output wire 51 and the rear output wire 52 in the portion 53 where the two output wires 5 intersect. More specifically, the insulating portion 6 is positioned throughout the space of the wiring outlet hole 30, between the front output wire 51 and the rear output wire 52 located within this space. In this configuration, since the insulating portion 6 is interposed between the front output wire 51 and the rear output wire 52 in the portion 53 where the two output wires 5 intersect, it is possible to prevent the two output wires 5 from becoming electrically conductive.

[0026] In this embodiment, the insulating portion 6 includes a first insulating portion 61 and a second insulating portion 62. The first insulating portion 61 is an insulating sheet sandwiched between the front-side and rear-side outlet wiring 52 in the intersection portion 53 of the two outlet wirings 5 ​​in the space of the wiring outlet hole 30.

[0027] The second insulating portion 62 is made of resin filled into the space of the wiring outlet hole 30. As shown in Figures 1B and 1C, this resin is formed when the sealing material 4 (small piece sealing material 42), which has been 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, silicone resin. In this configuration, the filling resin in the wiring outlet hole 30 can also serve as an insulating portion 6 that prevents electrical conductivity between the two intersecting outlet wires 5 (see Figure 1A).

[0028] The terminal box 7 is provided with a partition wall 70 that separates the front output wiring 51 and the rear output wiring 52 of the two output wirings 5 ​​arranged inside the terminal box 7. The partition wall 70 is interposed in the portion of the two output wirings 5 ​​where the two output wirings do not intersect. In this embodiment, the partition wall 70 is interposed in the portion of the two output wirings 5 ​​that is on the side opposite to the light-receiving side from the portion 53 where the two output wirings intersect. It is made of resin and is in the shape of a rectangular plate. Note that the solar cell module 1 does not necessarily have to be equipped with a partition wall 70.

[0029] In this embodiment, since the two output wires 5 intersect within the space of the output hole 30, the angle of change of direction of the output wires 5 (radius of curvature of the curve) can be increased, thus reducing stress on the output wires 5.

[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 two output wires 5 intersected within the space of the wiring output hole 30 in the back protective plate 3, but as shown in Figure 3A, they may also intersect within the internal space of the terminal box 7. That is, the portion 53 where the two output wires 5 intersect may be located inside the terminal box 7. Inside the terminal box 7, an insulating portion 6 is interposed between the two output wires 5, in the portion 53 where these two output wires 5 intersect. This insulating portion 6 is an insulating sheet sandwiched between the front output wire 51 and the rear output wire 52 in the portion 53 where the two output wires 5 intersect within the internal space of the terminal box 7. Furthermore, in this configuration, as shown in Figures 3B and 3C, after the lamination process, resin is filled into the space of the wiring output hole 30.

[0032] The insulating portion 6 may be made of resin filled into the internal space of the terminal box 7. In this configuration, the resin filling inside the terminal box 7 can also serve as the insulating portion 6 that prevents electrical conductivity between the two intersecting output wires 5.

[0033] In the above embodiment, the insulating portion 6 was a resin filling the space or an insulating sheet, but it may also be an insulating tape wrapped around the intersection portion 53 of the two output wires 5.

[0034] Alternatively, the intersection 53 of the two output wires 5 may be fixed. Specifically, the intersection 53 of the two output wires 5 may be fixed with resin tape. This configuration prevents the shape of the intersection of the two output wires 5 from changing during the lamination process.

[0035] The output wiring 5 may have an expandable section whose expansion and contraction ratio in the extension direction is set to be larger than that of other parts. 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, and since it does not affect other parts (parts other than the expandable section), the output wiring 5 is less likely to break.

[0036] This expandable portion may have multiple wave-like sections formed by the solid conductive material undulating in the thickness direction. That is, the expandable portion may have multiple wave-like sections that are curved without corners (bent sections) in a side view. Since the wave-like sections do not have corners, stress concentration is less likely to occur. In this configuration, the expandable portion of the extraction wiring 5 can be formed by bending alone. The expandable portion may also be formed in a bellows-like shape, that is, having multiple bent sections.

[0037] Furthermore, the expandable portion may be sandwiched between the light-receiving protective plate 2 and the back protective plate 3, and may be positioned around the wiring outlet hole 30 of the back protective plate 3, or inside the wiring outlet hole 30. In other words, the expandable portion may be located between the light-receiving protective plate 2 and the back protective plate 3, near the wiring outlet hole 30, or inside the wiring outlet hole 30. In this configuration, the wiring 5 is bent to be brought out of the module 1, and the expandable portion can absorb the stress generated near the wiring outlet hole 30 or inside the wiring outlet hole 30, where stress due to thermal expansion and contraction tends to be large.

[0038] The expandable portion may be made of a hollow conductive material. Specifically, the expandable portion may be a mesh-like portion made of a conductive material, or a portion in which multiple through holes or notches penetrating in the thickness direction are formed. In this case, the expandable portion of the extraction wiring 5 can be made into a flat shape (a shape that is not wavy). In addition to the wavy portion, it may also have a mesh-like portion made of a conductive material, etc. Furthermore, the expandable portion may be a mesh-like portion, etc., as well as a portion that has a wavy shape.

[0039] Based on the above, the present invention provides a solar cell module in which the output wiring is less prone to breakage.

[0040] The solar cell module of the present invention is a solar cell module including a light-receiving side protection plate and a back side protection plate facing each other, and a plurality of solar cells sandwiched between the light-receiving side protection plate and the back side protection plate via a sealing material. The back side protection plate has a wiring extraction hole penetrating in the thickness direction. A pair of strip-shaped extraction wirings for extracting current outside the module are connected to the plurality of solar cells. The pair of extraction wirings extend outside the module through the wiring extraction hole. The pair of extraction wirings enter the wiring extraction hole from different directions, and the pair of extraction wirings are arranged shifted in a direction along the plane in plan view and intersect at an angle in side view.

[0041] According to such a configuration, the pair of extraction wirings can be taken out of the module in a crossed state, and each extraction wiring can be arranged without being bent, so the extraction wiring is unlikely to be disconnected.

[0042] In the solar cell module, an insulating portion may be interposed between the pair of extraction wirings at the intersecting portion.

[0043] According to such a configuration, the insulating portion can prevent the pair of extraction wirings from being electrically connected.

[0044] In the solar cell module, a terminal box is provided outside the back side protection plate so as to cover the wiring extraction hole, and the insulating portion may be composed of a resin filled in the space of the wiring extraction hole or the internal space of the terminal box.

[0045] According to such a configuration, the filling resin in the terminal box can also serve as an insulating portion for preventing the conduction of the extraction wiring.

[0046] 1... solar cell module, 2... light-receiving side protection plate, 3... back side protection plate, 4... sealing material, 5... extraction wiring, 6... insulating portion, 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... intersecting portion, 61... first insulating portion, 62... second insulating portion, 70... partition wall

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 a wiring outlet hole penetrating in the thickness direction, a pair of strip-shaped outlet wirings for extracting current to the outside of the module are connected to the plurality of solar cells, the pair of outlet wirings extending to the outside of the module through the wiring outlet hole, the pair of outlet wirings connected to the plurality of solar cells entering the wiring outlet hole from different directions, the pair of outlet wirings being offset in a direction along the surface in a plan view and intersecting at an angle in a side view.

2. The solar cell module according to claim 1, wherein an insulating portion is interposed between the pair of output wirings at the intersecting portion.

3. A terminal box is provided on the outside of the rear protective plate so as to cover the wiring outlet hole, and the insulating portion is made of resin filled in the space of the wiring outlet hole or the internal space of the terminal box, as described in claim 2.

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