Solar cell modules

Abstract

To provide a solar cell module that can improve moisture resistance without increasing weight. [Solution] The solar cell module 10 comprises a laminate L that sandwiches solar cells 11 between a glass plate 12 and a back sheet 13, a frame 14 having a fitting portion 141 into which the laminate L is fitted and attached around the laminate L, and an end-face sealing resin 15 that is placed between the fitting portion 141 and the laminate L and covers the end face of the laminate L. The back sheet 13 has a structure in which a metal film 131 is sandwiched from both sides in the thickness direction by an insulating film 132, and a corner edge 133 is formed so as to be inside the outer peripheral edge of the glass plate 12 at the corner. The end face of the corner of the back sheet 13 is covered with an insulating resin 16.

Description

Technical Field

[0001] The present disclosure relates to a solar cell module. Background Art

[0002] In recent years, N-type TOPCon (Tunnel Oxide Passivated Contact) cells have become mainstream in solar cell modules. TOPCon cells are characterized by having a structure of a tunnel oxide film / heavily doped polycrystalline layer on a Si substrate on the back side of the cell. For example, compared with a P-type single crystal cell (PERC) having a heavily doped layer on the back side of the cell, a TOPCon cell has a tunnel oxide film / heavily doped polycrystalline layer on the back side of the cell, thereby increasing the back surface passivation effect and enabling higher performance of the cell.

[0003] However, although N-type TOPCon cells can achieve higher output than conventional PERC cells, they have a problem of being vulnerable to humidity. In general, modules of N-type cells also tend to be more vulnerable to humidity than modules of P-type cells. In conventional solar cell modules, a configuration in which a glass plate is disposed on the front side of the cell and the back side of the cell is covered with a back sheet made of PET (polyethylene terephthalate) is widely used. However, a PET back sheet allows water vapor permeation, and thus cannot provide sufficient moisture resistance for N-type TOPCon cells.

[0004] Patent Document 1 discloses, as a solar cell module with improved moisture resistance, a structure using glass not only on the front surface but also on the back surface of the cell (laminated glass structure). Prior Art Documents Patent Documents

[0005] Patent Document 1 Japanese Patent No. 6862486 Summary of the Invention [Problems that the invention aims to solve]

[0006] While laminated glass solar cell modules offer improved moisture resistance, they suffer from increased weight compared to modules using a backsheet.

[0007] This disclosure has been made in view of the above-mentioned problems, and aims to provide a solar cell module that can improve moisture resistance without increasing its weight. [Means for solving the problem]

[0008] To solve the above problems, the solar cell module of the present disclosure comprises a laminate that sandwiches solar cells between a glass plate and a back sheet, a frame having a fitting portion into which the laminate is fitted, thereby being attached around the laminate, and a first insulating material disposed between the fitting portion and the laminate and covering the end face of the laminate, wherein the back sheet has a structure in which a metal film is sandwiched between insulating films on both sides in the thickness direction, and a corner edge is formed such that it is located inside the outer peripheral edge of the glass plate at the corner, and the end face of the corner of the back sheet is covered with a second insulating material different from the first insulating material.

[0009] Furthermore, the solar cell module may be configured such that a portion of the corner edge is not covered by the frame, and a portion of the second insulating material is exposed on the back surface of the solar cell module.

[0010] Furthermore, in the above-mentioned solar cell module, the solar cell can be configured as an N-type cell.

[0011] Furthermore, in the above-mentioned solar cell module, the solar cell can be configured to be an N-type TOPCon cell.

[0012] Furthermore, the solar cell module can be configured such that the entire outer periphery of the backsheet is covered by the first insulating material and the second insulating material.

[0013] Furthermore, in the above-mentioned solar cell module, the second insulating material can be made of resin. [Effects of the Invention]

[0014] The solar cell module disclosed herein offers the advantage of improving the moisture resistance of the cells without increasing the weight of the module, by protecting the back side of the solar cells with a backsheet containing a metal film. [Brief explanation of the drawing]

[0015] [Figure 1] This is a plan view of a solar cell module according to one embodiment of the present disclosure. [Figure 2] This is a cross-sectional view of the solar cell module near its end. [Figure 3] This is a cross-section of the back seat. [Figure 4] This is a plan view showing the coating area of ​​the end face coating resin in a conventional solar cell module. [Figure 5] (a) to (c) are plan views showing the shape of the corner edges of the backsheet. [Figure 6] This is a plan view showing the application areas of end-face coating resin and insulating resin in a solar cell module. [Figure 7] This is a plan view showing the positional conditions between the corner edge and the conductive component. [Figure 8] This is a cross-sectional view of a solar cell module near its corner. [Figure 9] This is a cross-sectional view of a solar cell module near its corner. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a plan view of a solar cell module 10 according to an embodiment of the present disclosure.

[0017] As shown in FIG. 1, the solar cell module 10 includes a plurality of solar cells 11 arranged in a matrix. In the plurality of solar cells 11 arranged in a matrix, the plurality of solar cells 11 are electrically connected to each other in series to constitute solar cell strings, and the plurality of solar cell strings are electrically connected to each other in series or parallel via bus bars 17, and the electric power generated is extracted via the bus bars 17. Although details will be described later, the solar cell module 10 has a structure that provides high moisture resistance for the solar cells 11. Therefore, the solar cell module 10 is suitable when moisture-sensitive solar cells 11 such as N-type cells (particularly N-type TOPCon cells) are used. However, depending on the application, high moisture resistance may be required regardless of the type of solar cells 11, and the type of solar cells 11 in the solar cell module 10 is not particularly limited.

[0018] Hereinafter, the encapsulation structure of the solar cells 11 in the solar cell module 10 will be described. FIG. 2 is a cross-sectional view near the end of the solar cell module 10. The cross-section in FIG. 2 corresponds to the A-A cross-section in FIG. 1, and this A-A cross-section shows a cross-section at a location other than a corner of the solar cell module 10 (a location some distance away from the corner).

[0019] As shown in FIG. 2, in the solar cell 11, a glass plate 12 is disposed on the front surface side (light-receiving surface side), and the back surface side is covered with a back sheet 13. Accordingly, a laminate L in which the solar cells 11 are sandwiched between the glass plate 12 and the back sheet 13 is formed. In the laminate L, the periphery of the solar cells 11 (between the glass plate 12 and the back sheet 13) is sealed with a sealing material 18. For example, EVA resin is used as the sealing material 18.

[0020] A frame 14 is attached around the laminate L. Specifically, the frame 14 has a fitting portion 141 into which the laminate L is fitted. In addition, an end-face coating resin 15 (first insulating material) is placed between the fitting portion 141 and the end face of the laminate L. In this embodiment, as shown in Figure 2, the end-face coating resin 15 is filled between the fitting portion 141 and the end face of the laminate L, except at the corners of the solar cell module 10. The end-face coating resin 15 has the function of coating the end face of the laminate L and insulating the end face from the fitting portion 141, but it is also preferable that it functions as an adhesive to bond the laminate L and the frame 14. For this reason, silicone resin can be suitably used for the end-face coating resin 15.

[0021] Figure 3 is a cross-sectional view of the backsheet 13. As shown in Figure 3, the backsheet 13 has a structure in which a metal film 131 is sandwiched between insulating films 132 on both sides in the thickness direction. The metal film 131 is preferably an Al (aluminum) film. The insulating film 132 is preferably a resin film such as PET. Because the backsheet 13 has a metal film 131, it is less permeable to water vapor and oxygen compared to a backsheet with only a resin film. As a result, the solar cells 11 in the solar cell module 10 are protected from water vapor (and oxygen) on the front side by the glass plate 12 and on the back side by the backsheet 13, improving moisture resistance. In addition, by protecting the back side of the solar cells 11 with the backsheet 13, the solar cell module 10 can avoid the increase in module weight that would occur with a laminated glass structure.

[0022] When using a backsheet 13 having a metal film 131, it is necessary to ensure insulation between the backsheet 13 and the frame 14. That is, although the backsheet 13 has insulation ensured by an insulating film 132 on both main surfaces, the metal film 131 is exposed at the end surfaces. Furthermore, the frame 14 is usually made of a metal such as aluminum from the viewpoint of strength and durability of the solar cell module 10. For this reason, the solar cell module 10 needs to have an insulating structure that prevents the exposed metal film 131 from coming into contact with the frame 14.

[0023] As described above, in most of the outer periphery of the solar cell module 10, the end-face coating resin 15 is placed between the fitting portion 141 and the end face of the laminate L, so that the back sheet 13 and the frame 14 are also insulated by the end-face coating resin 15. However, in the conventional method that uses only the end-face coating resin 15, sufficient insulation by the end-face coating resin 15 may not be obtained at the corners of the solar cell module 10. To explain this, the conventional method will first be described with reference to Figure 4.

[0024] Conventionally, a method is used in which an end-face coating resin 15 is applied to the inside of the fitting portion 141 of the frame 14, and then the laminate L is inserted into the fitting portion 141. In this case, as shown in Figure 4, the area on which the end-face coating resin 15 is applied to the frame 14 is not the entire circumference of the solar cell module 10, and the end-face coating resin 15 is not applied to the corners. This is because if the end-face coating resin 15 is applied to the frame 14 even at the corners, the excess end-face coating resin 15 will overflow from the fitting portion 141 when the laminate L is inserted, staining the exposed surface of the laminate L and impairing the appearance of the solar cell module 10.

[0025] On the other hand, if the end-face coating resin 15 is not applied to the frame 14 at the corners, the end-face coating resin 15 may not sufficiently wrap around the fitting portion 141 and the laminate L at the corners, potentially reducing the insulation between the back sheet 13 and the frame 14. Furthermore, in conventional configurations, the back sheet 13 is cut to the same shape and size as the glass plate 12, and the four corners of the back sheet 13 are approximately right angles. In this case, contact between the end face of the back sheet 13 and the inner wall surface of the fitting portion 141 can easily occur at the corners.

[0026] Next, the sealing structure of the solar cell module 10 of this embodiment will be described. First, in the solar cell module 10, the backsheet 13 is not the same shape as the glass plate 12. As shown in Figures 5(a) to (c), a part of the backsheet 13 is cut out at the corners of the solar cell module 10, and a corner edge 133 is formed at the corner of the backsheet 13. That is, the corner edge 133 is located inside the outer peripheral edge of the glass plate 12 in a plan view of the laminate L. The edge shape of the corner edge 133 on the backsheet 13 is not particularly limited and can be a chamfered cut (see Figure 5(a)), a rounded cut (see Figure 5(b)), a polygonal cut (see Figure 5(c)), etc. Although Figures 5(a) to (c) illustrate one corner of the solar cell module 10, the backsheet 13 has corner edges 133 formed similarly at all four corners.

[0027] Furthermore, at the corners of the solar cell module 10, as shown in Figure 6, an insulating resin 16 (second insulating material) is applied along the corner edge 133, that is, to cover the boundary between the backsheet 13 and the glass plate 12. As a result, the end face of the backsheet 13 that is cut off at the corner edge 133 is covered with the insulating resin 16.

[0028] Furthermore, the amount of material removed from the corner edge 133 is relatively large, and at least a portion of the corner edge 133 is not covered by the frame 14. As a result, a portion of the area where the insulating resin 16 is applied is exposed on the back surface of the solar cell module 10. In addition, the corner edge 133 is formed to ensure the necessary insulation distance in the in-plane direction from conductive components (e.g., solar cells 11 and busbars 17) within the solar cell module 10. Specifically, as shown in Figure 7, when the shortest distance between the corner edge 133 and the conductive component (busbars 17 are exemplified in Figure 7) is D, the corner edge 133 is formed such that the shortest distance D is greater than the necessary insulation distance. The corner edge 133 may also be formed such that the shortest distance between the corner edge 133 and the solar cell 11 is greater than the necessary insulation distance.

[0029] At the corners of the solar cell module 10, a corner edge 133 is formed on the backsheet 13, so that, as shown in Figures 8 and 9, a portion of the sealing material 18 (the portion outside the corner edge 133) is exposed and not covered by the backsheet 13. Also, as shown in Figure 7, the corner edge 133 is located outside the solar cell 11 in a plan view of the laminate L. By forming the corner edge 133 on the outside of the solar cell 11 and arranging the backsheet 13 to completely cover the back surface of the solar cell 11 within the solar cell module 10, a structure with high moisture resistance to the solar cell 11 is achieved. Furthermore, at the corners of the solar cell module 10, by forming the sealing material 18 outside the corner edge 133, insulation between the corner edge 133 and the solar cell 11 can also be ensured by the sealing material 18.

[0030] The end-face coating resin 15 is applied so as to cover the end face of the backsheet 13 on all four sides except for the corner edges 133. In other words, in the solar cell module 10, by making the corner edges 133 large, the coating area of ​​the end-face coating resin 15 can be extended without unnecessarily expanding the coating area (without causing excess end-face coating resin 15 to protrude from the fitting portion 141), and both ends of the corner edges 133 can reach the coating area of ​​the end-face coating resin 15. As a result, the coating area of ​​the end-face coating resin 15 and the coating area of ​​the insulating resin 16 overlap at their ends, as shown in Figure 6. That is, the end-face coating resin 15 and the insulating resin 16 are formed continuously along the entire outer circumference of the backsheet 13.

[0031] In this embodiment, the first insulating material and the second insulating material described in the claims are both exemplified as resins (end-face coating resin 15 and insulating resin 16). However, the first insulating material and / or the second insulating material do not necessarily have to be resin-based. Also, the insulating material is not limited to a form that is applied, such as a liquid or paste, but may also be a form that is attached, such as a tape or sheet. Alternatively, the first insulating material and / or the second insulating material may be used in combination with a resin that is applied and cured, as in this embodiment, and a tape or sheet. Furthermore, the first insulating material and the second insulating material may be formed in separate processes, or they may be made of the same insulating material. Also, when both the first insulating material and the second insulating material are resins, they may be made of the same resin material or different resin materials. When the insulating resin 16 is made of a different material from the end-face coating resin 15, for example, a fast-drying two-component mixed resin can be suitably used.

[0032] Figures 8 and 9 are cross-sectional views (BB and CC cross-sectional views in Figure 1) of the solar cell module 10 near the corners. As shown in Figures 8 and 9, even in the corners of the solar cell module 10 where the end face coating resin 15 does not sufficiently wrap around into the fitting portion 141, the corner edge 133 is formed, allowing the end face of the backsheet 13 to be insulated and sealed by the insulating resin 16. As a result, the solar cell module 10 can ensure insulation between the backsheet 13 and the frame 14 over the entire outer circumference of the solar cell module 10 by the end face coating resin 15 and the insulating resin 16.

[0033] Furthermore, the application process of the insulating resin 16 in the solar cell module 10 may be performed either before or after the process of fitting the laminate L into the fitting portion 141 of the frame 14 (fitting process). If the application process is performed before the fitting process, the insulating resin 16 can be easily applied along the corner edge 133 of the backsheet 13 without being obstructed by the frame 14. If the application process is performed after the fitting process, the insulating resin 16 is applied in such a way that it fills the gap between the fitting portion 141 and the laminate L before curing, so the insulating resin 16 can function as an adhesive, which is expected to lead to an improvement in the strength of the solar cell module 10.

[0034] Furthermore, as shown in Figure 6, a portion of the insulating resin 16 in the solar cell module 10 is not covered by the frame 14 and is exposed on the back surface of the solar cell module 10. However, the insulating resin 16 is not exposed on the front surface of the solar cell module 10, and therefore has no effect on the appearance of the solar cell module 10.

[0035] The embodiments disclosed herein are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of this disclosure is not to be interpreted solely by the embodiments described above, but rather by the claims. [Explanation of Symbols]

[0036] 10 solar modules 11 solar cells 12 glass plates 13 Backseat 131 Metal film 132 Insulating film 133 Corner edge 14 Frame 141 Fitting part 15 End face coating resin (first insulating material) 16. Insulating resin (second insulating material) 17 Bus Bar 18. Sealing material L laminate

Claims

1. A laminate in which solar cells are sandwiched between glass plates and backsheets, A frame having a fitting portion into which the laminate is fitted, thereby being attached around the laminate, The system comprises a first insulating material disposed between the fitting portion and the laminate, and covering the end face of the laminate, The back sheet has a structure in which a metal film is sandwiched between insulating films on both sides in the thickness direction, and the corner edges are formed so that they are located inside the outer edge of the glass plate at the corners. A solar cell module characterized in that the end faces of the corners of the backsheet are covered with a second insulating material different from the first insulating material.

2. A solar cell module according to claim 1, A solar cell module characterized in that a portion of the corner edge is not covered by the frame, and a portion of the second insulating material is exposed on the back surface of the solar cell module.

3. A solar cell module according to claim 1 or 2, The solar cell module is characterized in that the solar cell is an N-type cell.

4. A solar cell module according to claim 3, The solar cell module is characterized in that the solar cell is an N-type Topcon cell.

5. A solar cell module according to claim 1 or 2, A solar cell module characterized in that the entire outer periphery of the backsheet is covered with the first insulating material and the second insulating material.

6. A solar cell module according to claim 1 or 2, A solar cell module characterized in that the second insulating material is a resin.

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