WO2009046531A1

WO2009046531A1 - Integrated photovoltaic roof tile

Info

Publication number: WO2009046531A1
Application number: PCT/CA2008/001794
Authority: WO
Inventors: Sass M. Peress
Original assignee: Icp Global Technologies Inc.
Priority date: 2007-10-11
Filing date: 2008-10-10
Publication date: 2009-04-16

Abstract

An integrated photovoltaic roof tile which comprises a photovoltaic cell assembly portion having a photovoltaic cell and a junction box in communication with the photovoltaic cell for cabling and a frame portion molded around to rigidly hold peripheral edges of the photovoltaic cell assembly is disclosed. The frame is contour shaped and sized to fit and to interconnect with an adjacent standard roof tile or another integrated photovoltaic roof tile. The integrated photovoltaic roof tile is designed for converting solar energy into electrical energy.

Description

INTEGRATED PHOTOVOLTAIC ROOF TILE

FIELD OF THE INVENTION

[0001 ] The present invention relates to a building element, more particularly a roof tile that is integrated with a photovoltaic module for converting solar energy into electrical energy.

BACKGROUND OF THE INVENTION

[0002] Within the grid connected photovoltaic industry there is a growing demand for building integrated photovoltaic solutions (BIPV). There are a number of solutions available today, including standard solar cell module that is designed for roof integration, slates with integrated crystalline solar cell, tiles with integrated crystalline solar cell, slates with glued-on solar cells, and tiles with glued-on solar cells. Up till now BIPV has had a much smaller market share than non-integrated photovoltaic solution, this is mainly because these solutions lack cost- competitiveness, ease of installation, and ease of integrating in the building planning process. Especially, slates and roof tiles with glued-on solar cells suffer from not being able to provide durable connection, and the connecting/joining process is very time consuming and requires special skills for installation, such that the performance may vary from installation to installation. Also, it is found that the glue / adhesive may be degraded over time due to exposure to the extreme environmental conditions, including heat effects, moistures, chemical, etc, and may cause breakages in the bonding structures.

[0003] Since for various stakeholders the advantages of BIPV are clear the potential for a break through solution can be enormous. More and more governments are putting in place favorable subsidy programs for BIPV, architects only want to include photovoltaic (PV) in their design when it is BIPV and real estate developers are not interested to include PV when this alters the building planning process, further more real estate developers are now keen on offering "add-on" renewable power sources for reducing green gas emissions.

[0004] An object of the present invention is to provide a photovoltaic roof tile that is cost effective and easy to install without requiring any special skill and knowledge regarding photovoltaic building materials.

[0005] Another object of the present invention is to provide a photovoltaic roof tile that is easily integrated in the roof aesthetically.

[0006] Yet another object of the present invention is to provide a photovoltaic roof tile that is physically and easily integrated in the roof.

[0007] Yet further object of the present invention is to provide a photovoltaic roof tile that is easily integrated in the building process.

[0008] Yet another object of the present invention is to provide an effective manufacturing process of roof tile and solar cell integration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention will now be described in more detail with reference to the accompanying drawings, in which:

[0010] Figure IA illustrates the perspective view of an integrated photovoltaic roof tile of a preferred embodiment of the present invention;

[0011] Figure IB illustrates a bottom perspective view of the integrated photovoltaic roof tile;

[0012] Figure 2 illustrates a top view of the integrated photovoltaic roof tile;

[0013] Figure 2A is a sectional view of the integrated photovoltaic roof tile, denoted by A-A in Figure 2; [0014] Figure 2B is a sectional view of the integrated photovoltaic roof tile, denoted by B-B in Figure 2;

[0015] Figure 2C is a sectional view of the integrated photovoltaic roof tile, denoted by C-C in Figure 2;

[0016] Figure 2D is a sectional view of the integrated photovoltaic roof tile, denoted by D-D in Figure 2;

[0017] Figure 3 illustrates a front view of the integrated photovoltaic roof tile;

[0018] Figure 4 is a side view of the integrated photovoltaic roof tile;

[0019] Figure 5 is a bottom view of the laminated thin film photovoltaic cell of the integrated photovoltaic roof tile;

[0020] Figure 6 is a block diagram showing a aggregated connection topology;

[0021] Figure 7 is a block diagram showing a distributed connection topology;

[0022] Figure 8 is a perspective view of the integrated photovoltaic roof tiles showing that the integrated photovoltaic roof tiles being installed with roof tiles;

[0023] Figures 9 is an enlarged perspective view showing interconnections of four integrated photovoltaic roof tiles;

[0024] Figure 10 is an enlarged perspective view showing interconnection of two integrated photovoltaic roof tiles and two standard roof tiles;

[0025] Figure 11 is an enlarged perspective view showing interconnection of one integrated photovoltaic roof tile and three standard roof tiles; and

[0026] Figure 12 shows an enlarged perspective view showing interconnection of one integrated photovoltaic roof tile and adjacent standard roof tiles. DETAILED DESCRIPTION OF THE INVENTION

[0027] According to a preferred embodiment of the present invention, it provides an integrated photovoltaic roof tile 10 that offers benefits in aesthetical integration and in ease of installation. The integrated photovoltaic roof tile 10 can be mounted / installed just like a standard roof tile, and since no separate mounting system is required, the integrated photovoltaic roof tile 10 is highly suitable to be integrated in the normal construction process of residential construction projects at minimum installation costs.

[0028] Figure IA is a perspective view of an integrated photovoltaic roof tile 10 of a preferred embodiment of the present invention. The integrated photovoltaic roof tile 10 comprises a sheet of a laminated thin film photovoltaic cell 20 and a frame 30, enclosing and surrounding outer edge of the laminated thin film photovoltaic cell 20.

[0029] Thin film solar cell has a better performance under the heat than crystalline solar cell. The negative effect of heat on the power output cannot be ignored as such heat usually plays a bigger role in integrated solar cell application, such as the integrated photovoltaic roof tile application, than it does in standard module applications. The negative effect is bigger for crystalline cells than it is for thin film. Based on the experiment, crystalline cells have approximately -0.45% / K of negative effect of heat on the power output, where the thin film is about -0.2 % / K.

[0030] Reaction Injection Molding and its derivative technologies, such as Reinforced Reaction Injection Molding (RRIM) and Structural Reaction Injection Molding (SREVI), offer solutions for encapsulating the laminated thin film solar cells 20 in various geometrical shapes and colors. Therefore standard roof tiles can be imitated with Polyurethane (PU). In this preferred embodiment of the present invention, the frame 30 comprises top 31, bottom 32, right 33 and left side 34 sections, where each section is shaped to fit and interconnect with the popular standard roof tiles, like Gredos^®, Teide^® and Guadarrama^®. A plurality of predefined screw holes 21 are located on top side 31 and/or bottom side 32 of the integrated photovoltaic roof tile 10 for fastening it onto the roof. As it can be seen, the integrated photovoltaic roof tile 10 looks just like a standard roof tile, and it is easy to install just like the standard roof tile. The integrated photovoltaic roof tile 10 does not alter the rest of the building process and can be produced in a one-step process. Since the PU imitates on the contour the roof tile shape whatever the shape of the tile or the slate, and therefore the integrated photovoltaic roof tile 10 integrates physically and aesthetically in the roof.

[0031] Figure IB is a bottom perspective view of the integrated photovoltaic roof tile 10. A junction box 23, comprising a cable 25 terminated with a plug 24 and a receiving end 26 for receiving a plug 24 of an adjacent integrated photovoltaic roof tile 10, is attached to the bottom surface 27 of the laminated thin film solar cell 20. The cable 25 is sufficient in length so that the plug 24 can be reach to a receiving end of a vertically or horizontally adjacent integrated photovoltaic roof tile 10. Therefore, the integrated photovoltaic roof tile 10 does not require a separate wiring system for cascading / aggregating the integrated photovoltaic roof tiles 10. Under the integrated photovoltaic roof tile 10, the frame 30 provides a sufficient space between the bottom surface 27 of the laminated thin film solar cell 20 and the roof surface (not shown) for routing electrical wires for interconnecting the integrated photovoltaic roof tiles 10 and/or to renewable power device(s), such as DC/ AC converters (not shown)

[0032] Referring to Figures 2, 3 and 8, the bottom side 32 of the frame 30 is shaped to fit weather-tightly to the top side 31' of a vertical adjacent roof tile 100 or the top side 31 of a vertical adjacent integrated photovoltaic roof tile 10. The right side 33 comprises a hook-like shaped flange 36, which is shaped to fit weather- tightly on the top surface of a receiving flange 37 provided at the left side 35' of a horizontal adjacent roof tile 100 or at the left side 35 of a horizontally adjacent integrated photovoltaic roof tile 10.

[0033] Figure 4 shows a side view of the integrated roof tile 10, showing the left side 34 of the integrated photovoltaic roof tile 10.

[0034] The frame 30 is molded via a reaction injection molding process to enclose around the lateral edges of the laminated thin film solar cell 20. Figure 2A shows a sectional view of the frame 30 at A-A in Figure 2. Likewise, Figure 2B shows a sectional view at B-B, Figure 2C shows a sectional view at C-C, and Figure 2D shows a sectional view at D-D in Figure 2. The frame 30 extends inwardly toward the outer edge 29 of the laminated thin film solar cell 20 and covers portions of both upper 28 and bottom 27 surfaces of the laminated thin film solar cell 20, at least about 6 mm from the outer edge, securely holding the laminated thin film solar cell 20. In the preferred embodiment of the present invention, the laminated thin film solar cell 20 is laminated with a suitable material such as sheets of glass (not shown) to protect the thin film solar cell, with a total thickness of about 3.2mm.

[0035] Figure 5 shows a bottom view of the laminated thin film solar cell 20. The bottom surface 27 comprises a hole 21 for electrical wiring (not shown) from and to the thin film solar cell. In the preferred embodiment of the present invention, the laminated thin film solar cell 20 is monolithically integrated solar cell using a suitable technology, including, but not limited to cadmium telluride, amorphous silicon, micromorphous silicon (alone or tandem) or copper indium gllium selenide (or its variant). In the preferred embodiment of the present invention, the monolithically integrated solar cell is a rigid thin film solar cell. A junction box 23 (not shown) is attached near the hole 21 and for receiving the electrical wiring from the thin film solar cell of the laminated thin film solar cell 20, and thus, is electrically in communication with the thin film solar cell. In preferred embodiment of the present invention, the size of the laminated solar thin film cell 20 is 818mm by 291mm in size, and the hole 21 is about 30mm in diameter.

[0036] Figure 6 shows a connection topology for a single DC/ AC converter 60. In this topology, two sets of integrated photovoltaic roof tiles 10 are cascaded and aggregated to the single DC/ AC converter 60.

[0037] Figure 7 shows another connection topology for distributed DC/AC converters 60a and 60b.

[0038] Figure 8 shows an installation example of the integrated photovoltaic roof tiles 10 of the preferred embodiment of the present invention. The integrated photovoltaic roof tiles 10 overlay and interconnect with other integrated photovoltaic roof tiles 10 and standard roof tiles 100, vertically and horizontally. [0039] Figure 9 shows an enlarged perspective view showing four integrated photovoltaic roof tiles 10a, 10b, 10c and 1Od. A hook-like flange 36 provided at right side 33 of the frame 30a is about to rest on the upper surface of the receiving flange 37 of the frame 30b, and the bottom sides 32 of the frames 30a and 30b is about to rest on the top sides 31 of the frames 30c and 30d, respectfully.

[0040] Figure 10 shows an enlarged perspective view showing two integrated photovoltaic roof tile 10c and 1Od interconnected horizontally side by side, where the hook-like flange 36 provided at right side 33 of the frame 30c of the integrated photovoltaic roof tile 10c is resting on the receiving flange 37 of the frame 3Od of the integrated photovoltaic roof tile 1Od, and the bottom sides 32 of the frame 30a and 30b is resting on the top sides 31' of two standard roof tiles lOOe and 10Of, respectfully.

[0041] Figure 11 shows an enlarged perspective view showing one integrated photovoltaic roof tile 10c being interconnected with standard roofs 10Oy, 10Ox, and 10Oe, where the hook-like flange 36' provided at right side 33' of the standard roof tile lOOy is resting on the receiving flange 37 of the frame 30c of the integrated photovoltaic roof tile 10c, and the bottom side 32 of the frame 30c of the integrated photovoltaic roof tile 10c and the bottom side 32' of the standard roof lOOy are resting on the top sides 31' of two standard roof tiles lOOe and 10Ox, respectfully.

[0042] Figure 12 shows an enlarged perspective view showing one integrated photovoltaic roof tile 1Od being interconnected with standard roofs 10Oz and 10Of, where the hook- like flange 36 provided at right side 33 of the integrated photovoltaic roof tile 1Od is resting on the receiving flange 37' of the standard roof tile 10Oz, and the bottom side 32 of the integrated photovoltaic roof tile 1Od is resting on the top side 31' of the standard roof tile 10Of.

[0043] Method of Manufacturing:

[0044] The laminated thin film solar cell 20 is a monolithically integrated solar cell, created directly on a glass substrate or superstrate and all the electrical connections are created in situ. In the preferred embodiment of the present invention, the dimension of the thin film solar cell is 291 mm x 818 mm, and the total thickness is about 3.2mm. A small hole is placed at the bottom of the thin film solar cell for placing the needed cabling, connectors and electrical components, including junction box 23. This laminated thin film solar cell 20 is, then, placed in a mold, if needed together with inserts, for forming a frame 30 around the laminated thin film solar cell 20. Via a suitable reaction injection molding (RIM) process, the laminated thin film solar cell is encapsulated with PU material, forming the frame 30. The PU takes the designed form to match the shape of a particular type of a roof tile.

[0045] It is to be understood that the embodiments and variations shown and described herein are merely illustrations of the principles of this invention and that various modifications may be implemented by those skilled in the art without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. An integrated photovoltaic roof tile, comprising:

- a photovoltaic cell assembly portion having a photovoltaic cell and a junction box in communication with the photovoltaic cell for cabling; and

- a frame portion molded around to rigidly hold peripheral edges of the photovoltaic cell assembly, the frame having a contour shaped and sized to fit and to interconnect with an adjacent standard roof tile or integrated photovoltaic roof tile.

2. The integrated photovoltaic roof tile as recited in claim 1 wherein the photovoltaic cell is a monolithically integrated photovoltaic cell.

3. The integrated photovoltaic roof tile as recited in claim 2 wherein the photovoltaic cell is a laminated thin film photovoltaic cell.

4. The integrated photovoltaic roof tile as recited in claim 1 wherein the frame is molded by reaction injection molding, reinforced reaction injection molding, or structural reaction injection molding.

5. The integrated photovoltaic roof tile as recited in claim 1 wherein the frame is molded with a polyurethane.

6. The integrated photovoltaic roof tile as recited in claim 1 wherein the frame provides a space around the junction box for interconnecting with other integrated photovoltaic roof tile.

7. A method of manufacturing an integrated photovoltaic roof tile, comprising:

RECTIFIED SHEET (RULE 91 .1) a. providing a laminated thin film photovoltaic cell;

b. placing a mold for forming a frame around the laminated thin film photovoltaic cell;

c. proceeding with a suitable reaction injection molding process to form the frame to encapsulate peripheral edges of the laminated thin film photovoltaic cell, the frame having a contour shaped and sized to fit and to interconnect with a standard roof tile.

10

RECTIFIED SHEET (RULE 91 .1)