Photovoltaic Roof Tile Base

Abstract

Described herein is a roof tile base configuration that is compatible with both photovoltaic (PV) roof tiles and non-PV roof tiles. The roof tile base includes a first set of retention features for fastening to the non-PV roof tile and a second set of retention features for fastening to the PV roof tile. In particular, the roof tile base includes several apertures sized to receive tile hooks located on the roof-facing surface of the PV roof tile. Engagement by the respective hooks of portions of the roof tile base that define the apertures serves to secure the PV roof tile to the roof tile base. The roof tile base also includes retention features on opposite sides of the roof tile base that are configured to lock into notches located on opposite side walls of the non-PV roof tile.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Patent Application No. 63 / 434,007, entitled "PHOTOVOLTAIC ROOFING TILE BASE," filed December 20, 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] This disclosure relates generally to photovoltaic (PV) roof tiles. More specifically, this disclosure describes a universal roof base configured to support either PV roof tiles or non-PV roof tiles. [Background technology]

[0003] In residential and commercial solar energy installations, PV modules, also called PV or solar panels, which may include a two-dimensional array (e.g., 6x12) of solar cells, are typically installed on the roofs of buildings. PV roof tiles (or solar roof tiles) can be a specific type of PV module that provides weather resistance and a pleasing aesthetic appearance for homes while also functioning as a PV module to convert solar energy into electricity. PV roof tiles can be shaped like traditional roof tiles and can include one or more solar cells encapsulated between front and back covers, but typically enclose fewer solar cells than traditional solar panels.

[0004] The front and back covers can be tempered glass or other materials that can protect the PV cells from weather elements. Note that the dimensions of a typical roof tile are 15 in x 8 in = 120 in. 2 =774cm 2 ,The dimensions of a typical solar cell are 6in x 6in = 36in 2 =232cm 2Generally, PV roof tile installations include a mixture of PV and non-PV roof tiles, since incorporating PV structures into every roof tile typically provides more energy than is required to power a typical home. For this reason, roof elements that can be used with both PV and non-PV roof tile modules are desirable, and can improve the affordability of PV roof configurations. Summary of the Invention

[0005] In some embodiments, the roof tile base includes features that enable the roof tile base to support both PV roof tiles and non-PV roof tiles.

[0006] In some embodiments, a roof tile assembly is disclosed that includes a photovoltaic (PV) roof tile having an optically transparent front cover, a back cover, a plurality of solar cells disposed between the optically transparent front cover and the back cover, and a plurality of tile hooks coupled to the back cover; and a roof tile base in direct contact with the back cover and having a sun-facing surface extending from a first side of the roof tile to a second side of the roof tile opposite the first side, a plurality of vertical standoffs configured to establish the height of the sun-facing surface above the roof substrate, and a plurality of apertures extending through the roof tile base, wherein a first of the plurality of tile hooks extends through a first of the plurality of apertures and engages a portion of the roof tile base that defines the first aperture.

[0007] In some embodiments, a roof tile assembly is disclosed including a non-photovoltaic (non-PV) roof tile comprising a sheet metal substrate with a flat central region, a first sidewall at a first end of the flat central region and defining a first notch, and a second sidewall at a second end of the flat central region opposite the first end and defining a second notch; and a roof tile base having a sun-facing surface in direct contact with the flat central region and extending from the first sidewall to the second sidewall, a plurality of vertical standoffs configured to establish the height of the sun-facing surface above the roof substrate, a first retention feature on a first side of the roof tile base engaged within the first notch of the first sidewall, and a second retention feature on a second side of the roof tile base engaged within the second notch of the second sidewall.

[0008] In some embodiments, a roof configuration is disclosed comprising a first roof tile assembly comprising a first roof tile base and a photovoltaic (PV) roof tile disposed on the first roof tile base, and a second roof tile assembly adjacent to the first roof tile assembly, the second roof tile assembly comprising a second roof tile base and a non-photovoltaic (non-PV) roof tile disposed on the second roof tile base, wherein the first roof tile base is the same as the second roof tile base.

[0009] A "solar cell strip," "PV strip," "small cell," or "strip" is a portion or segment of a PV structure, such as a solar cell. A PV structure can be divided into several strips. The strips can have any shape and any size. The width and length of the strips can be the same or different from each other. Strips can also be formed by further dividing a previously divided strip.

[0010] "Finger line," "finger electrode," and "finger" refer to an elongated conductive (eg, metal) electrode of a PV structure for collecting carriers.

[0011] A "bus bar," "bus line," or "bus electrode" refers to an elongated, conductive (e.g., metal) electrode of a PV structure for aggregating the current collected by two or more finger lines. A bus bar is typically wider than a finger line and can be deposited or otherwise positioned anywhere on or in the PV structure. A single PV structure can have one or more bus bars.

[0012] A "PV structure" can refer to a solar cell, a segment, or a solar cell strip. A PV structure is not limited to a device manufactured by a particular method. For example, a PV structure can be a crystalline silicon-based solar cell, a thin-film solar cell (e.g., a CdTe or CIGS thin-film solar cell), an amorphous silicon-based solar cell, a polycrystalline silicon-based solar cell, or a strip thereof. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates an exemplary configuration of PV roof tiles on a house.

[0014] [Figure 2] 1 is a perspective front view of an exemplary PV roof tile, according to one embodiment.

[0015] [Figure 3A] FIG. 2 illustrates an exemplary configuration of a multi-tile module, according to one embodiment.

[0016] [Figure 3B] 1 is a cross-sectional view of an exemplary multi-tile module, according to one embodiment.

[0017] [Figure 4A] FIG. 10 illustrates a series connection between three adjacent cascaded PV strips according to one embodiment.

[0018] [Figure 4B]FIG. 10 is a side view of a string of cascaded strips according to one embodiment.

[0019] [Figure 4C] FIG. 1 illustrates an exemplary solar roof tile, according to one embodiment.

[0020] [Figure 5A] FIG. 2 is a top view of an exemplary multi-tile module, according to one embodiment.

[0021] [Figure 5B] FIG. 2 is a top view of another exemplary solar roof tile, according to one embodiment.

[0022] [Figure 6] FIG. 1 is a partial view of a roof with several solar and passive roof tiles.

[0023] [Figure 7A] FIG. 1 is a perspective view of the sun-facing surface of a roof tile base. [Figure 7B] FIG. 1 is a perspective view of the roof-facing surface of a roof tile base.

[0024] [Figure 7C] 10 illustrates engagement of the lateral standoffs of the first roof tile base within the alignment notches of the second roof tile base.

[0025] [Figure 7D] 7D is a cross-sectional view of two roof tile bases taken along section line AA of FIG. 7C.

[0026] [Figure 7E] FIG. 1 is a perspective view of a corner of laterally adjacent roof tile bases.

[0027] [Figure 7F] 1 shows a cross-sectional view of a roof tile base with integral side laps through section line BB.

[0028] [Figure 8A] 1 shows a perspective view of a PV roof tile.

[0029] [Figure 8B] FIG. 8B is a perspective view of the PV roof tile shown in FIG. 8A positioned on a roof tile base.

[0030] [Figure 8C] 1 shows a PV roof tile fully engaged with a roof tile base.

[0031] [Figure 9A] FIG. 1 illustrates a non-PV roof tile and how it is configured to slide onto a roof tile base.

[0032] [Figure 9B] 1 shows a non-PV roof tile fully engaged with a roof tile base.

[0033] [Figure 10A] 1 illustrates an exemplary process for installing roof tiles on multiple roof tile bases on a house. [Figure 10B] 1 illustrates an exemplary process for installing roof tiles on multiple roof tile bases on a house. [Figure 10C] 1 illustrates an exemplary process for installing roof tiles on multiple roof tile bases on a house. [Figure 10D] 1 illustrates an exemplary process for installing roof tiles on multiple roof tile bases on a house. [Figure 10E] 1 illustrates an exemplary process for installing roof tiles on multiple roof tile bases on a house.

[0034] [Figure 11A] FIG. 10 illustrates how the height of different parts of a roof tile base varies. [Figure 11B]FIG. 10 illustrates how the height of different parts of a roof tile base varies. [Figure 11C] FIG. 10 illustrates how the height of different parts of a roof tile base varies. [Figure 11D] FIG. 10 illustrates how the height of different parts of a roof tile base varies. [Figure 11E] FIG. 10 illustrates how the height of different parts of a roof tile base varies. [Figure 11F] FIG. 10 illustrates how the height of different parts of a roof tile base varies. DETAILED DESCRIPTION OF THE INVENTION

[0035] The following description is presented to enable any person skilled in the art to make and use the embodiments, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the disclosure. Thus, the disclosed system is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. overview

[0036]

[0006] Embodiments of the present invention solve at least the technical problem of reducing the number of components required to join PV roof tiles and non-PV roof tiles together. In particular, the present disclosure describes a universal roof tile base that can be coupled to both PV roof tiles and non-PV roof tiles. The roof tile base includes a plurality of apertures that can be engaged by a plurality of hooks located on the roof-facing side of the PV roof tile. The hooks engage the edges of each aperture to secure the PV roof tile to the roof tile base. The roof tile base also includes retention features for securing the roof tile base to a roof substrate.

[0037] In addition to describing new PV roof tile bases, advances are described regarding the formation of robust and flexible non-PV roof tiles. In particular, roof tiles can be formed from sheet metal and finished to have the appearance of PV roof tiles. Forming roof tiles from sheet metal material results in non-PV roof tiles that can be efficiently cut to fit portions of roof peaks that would otherwise not accommodate rectangular roof tiles. For example, stock rectangular non-PV roof tiles can be cut to have nearly any polygonal shape. Several triangular tiles may be needed near various ridges and / or valleys on a particular roof peak. Triangular or trapezoidal pieces can be formed by applying one or two cuts to the non-PV roof tile. The combination of versatile legs formed from metal with non-PV roof tiles can substantially reduce the number of parts required to perform a PV roof installation.

[0038] A "solar cell" or "cell" is a PV structure capable of converting light into electricity. Cells can have any size and shape and can be made from a variety of materials. For example, a solar cell may be a PV structure fabricated on a silicon wafer, or one or more thin films on a substrate material (e.g., glass, plastic, or any other material capable of supporting a PV structure), or a combination thereof.

[0039] A "solar cell strip," "PV strip," "small cell," or "strip" is a portion or segment of a PV structure, such as a solar cell. A PV structure can be divided into several strips. The strips can have any shape and any size. The width and length of the strips can be the same or different from each other. Strips can also be formed by further dividing a previously divided strip.

[0040] "Finger line," "finger electrode," and "finger" refer to an elongated conductive (eg, metal) electrode of a PV structure for collecting carriers.

[0041] A "bus bar," "bus line," or "bus electrode" refers to an elongated, conductive (e.g., metal) electrode of a PV structure for aggregating the current collected by two or more finger lines. A bus bar is typically wider than a finger line and can be deposited or otherwise positioned anywhere on or in the PV structure. A single PV structure can have one or more bus bars.

[0042] A "PV structure" can refer to a solar cell, a segment, or a solar cell strip. A PV structure is not limited to a device manufactured by a particular method. For example, a PV structure can be a crystalline silicon-based solar cell, a thin-film solar cell, an amorphous silicon-based solar cell, a polycrystalline silicon-based solar cell, or a strip thereof. PV roof tiles and multi-tile modules

[0043] A PV roof tile (or solar roof tile) is a type of PV module shaped like a roof tile and typically encloses fewer solar cells than a conventional solar panel. Note that such a PV roof tile can function simultaneously as both a PV cell and a roof tile. In some embodiments, the systems disclosed herein can be applied to PV roof tiles and / or other types of PV modules.

[0044] 1 is a diagram illustrating an exemplary configuration of PV roof tiles on a house. PV roof tiles 100 can be installed on a house like traditional roof tiles or shingles. In particular, PV roof tiles can be arranged with other tiles to prevent water from entering a building.

[0045] A PV roof tile can enclose multiple solar cells or PV structures, each of which can include one or more electrodes, such as bus bars and finger lines. The PV structures within a PV roof tile can be electrically and optionally mechanically coupled to one another. For example, multiple PV structures can be electrically coupled to one another by metal tabs via their respective bus bars to form a series or parallel connection. Furthermore, an electrical connection can be made between two adjacent tiles so that several PV roof tiles can jointly provide power. Visual features of a PV roof tile can allow the PV roof tile to blend in and appear similar to non-PV roof tiles. In some embodiments, the visual features can be designed to perform ideally when viewed from angle 102.

[0046] Figure 2 is a perspective view of an exemplary PV roof tile, according to one embodiment. Solar cells 204 and 206 can be hermetically sealed between a top glass cover 202 and a PV back cover 208, which together can protect the solar cells from various weather elements. In the example shown in Figure 2, a metal tab strip 212 can contact the front electrode of solar cell 204 and extend beyond the left edge of glass 202, thereby serving as the PV roof tile's first polarity contact electrode. Tab strip 212 can also contact the back surface of solar cell 206, forming a series connection between solar cell 204 and solar cell 206. Meanwhile, tab strip 214 can contact the front electrode of solar cell 206 and extend beyond the right edge of glass cover 202, serving as the PV roof tile's second polarity contact electrode. In some embodiments, PV back cover 208 can be a standard PV tile backer formed from one or more layers of polymer, such as a fluoropolymer or a combination of PET and EVA layers. Alternatively, PV back cover 208 can take the form of a rear glass cover.

[0047] In some embodiments, the array of solar cells 204 and 206 can be encapsulated between a top glass cover 202 and a back cover 208. A top encapsulant layer, which can be polymer-based, can be used to seal the top glass cover 202 to the array of solar cells 204 / 206. Specifically, the top encapsulant layer can include polyvinyl butyral (PVB), thermoplastic polyolefin (TPO), ethylene vinyl acetate (EVA), or N,N'-diphenyl-N,N'-bis(3-methylphenyl)-l,l'-diphenyl-4,4'-diamine (TPD). Similarly, a bottom encapsulant layer, which can be similarly material-based, can be used to seal the array of solar cells to the back cover 208. PV roof tiles can also include other optional layers, such as optical filters or coating layers or layers of nanoparticles to provide a desired color appearance. In the example of FIG. 2, the module or roof tile 300 can also include an optical filter layer between the array of solar cells and the front glass cover 202.

[0048] To facilitate more scalable production and easier installation, multiple PV roof tiles can be fabricated together, with the tiles connected in a rigid or semi-rigid manner. FIG. 3A illustrates an exemplary configuration of a multi-tile module, according to one embodiment. In this example, three PV roof tiles 302, 304, 306 can be fabricated, with semi-rigid bonds 322, 324 established between adjacent tiles. Prefabricating multiple tiles into a rigid or semi-rigid multi-tile module can significantly reduce the complexity of rooftop installation, as the tiles within the module are connected with tab strips. Note that each multi-tile module may include more or fewer tiles than shown in FIG. 3A.

[0049] FIG. 3B is a cross-sectional view of an exemplary multi-tile module, according to one embodiment. In this example, multi-tile module 350 can include PV roof tiles 354, 356, and 358. These tiles can share a common PV tile backer 352 and can each have three individual glass covers 355, 357, and 359. Each tile can encapsulate two solar cells. For example, tile 354 can include solar cells 360 and 362 encapsulated between PV tile backer 352 and glass cover 355. Tab strips can be used to provide electrical connections within each tile and between adjacent tiles. For example, tab strip 366 can couple the front electrode of solar cell 360 to the back electrode of solar cell 362, forming a series connection between these two cells. Similarly, tab strip 368 can couple the front electrode of cell 362 to the back electrode of cell 364, forming a series connection between tiles 354 and 356.

[0050] Gaps 322 and 324 between adjacent PV tiles can be filled with an encapsulant to protect the tab strip interconnecting the two adjacent tiles from weather elements. For example, encapsulant 370 fills the gap between tiles 354 and 356 and protects tab strip 368 from weather elements. Additionally, the three glass covers, PV tile backer 352, and encapsulant together form a semi-rigid structure for multi-tile module 350. This semi-rigid structure can facilitate easier installation while providing some flexibility between tiles.

[0051] In addition to the examples shown in Figures 3A and 3B, PV tiles can include PV structures of different forms. For example, to reduce internal resistance, each square solar cell shown in Figure 3A can be divided into multiple (e.g., three) smaller strips, each with edge bus bars of different polarity on its two opposite edges. The edge bus bars allow strips to be cascaded one after another to form series-connected strings.

[0052] 4A illustrates a series connection between three adjacent cascaded PV strips, according to one embodiment. In FIG. 4A, strips 502, 504, and 506 are stacked such that strip 504 overlaps and partially underlies strip 506 adjacent to its right and overlaps strip 502 to its left. The resulting string of strips forms a cascading pattern similar to a roof shingle. Strips 502 and 504 are electrically coupled in series via edge bus bar 508 on the top surface of strip 502 and edge bus bar 510 on the bottom surface of strip 504. Strips 502 and 504 can be positioned such that bottom edge bus bar 510 is above and in direct contact with top edge bus bar 508. The coupling between strips 504 and 506 can be similar.

[0053] FIG. 4B is a side view of a string of cascaded strips, according to one embodiment. In the example shown in FIGS. 4A and 4B, the strips may be 6-inch square or pseudo-square segments of solar cells, with each strip measuring approximately 2 inches by 6 inches. To reduce shading, the overlap between adjacent strips should be kept as small as possible. Thus, in the example shown in FIGS. 4A and 4B, a single bus bar (both top and bottom) may be placed at or near the very edge of the strip. The same cascading pattern may extend along multiple strips to form a series-connected string, and multiple strings may be coupled in series or parallel.

[0054] FIG. 4C illustrates an exemplary solar roof tile, according to one embodiment. Solar roof tile 412 includes a top glass cover 414 and solar cells 416 and 418. The bottom cover (e.g., a PV tile backer) of solar roof tile 412 is not visible in FIG. 4C. Solar cells 416 and 418 can be traditional square or pseudo-square solar cells, such as 6-inch solar cells. In some embodiments, solar cells 416 and 418 can each be divided into three separate pieces of similar size. For example, solar cell 416 can include strips 422, 424, and 426. These strips can be arranged so that adjacent strips partially overlap at their edges, similar to what is shown in FIGS. 4A-4B . For simplicity of illustration, the electrode grid, including the finger lines and edge bus bars of the strips, is not shown in FIG. 4C . In addition to the example shown in FIG. 4C , a solar roof tile can include fewer or more cascaded strips, which can be of various shapes and sizes.

[0055] In some embodiments, multiple solar roof tiles, each enclosing a cascaded string, can be assembled to form a multi-tile module. Electrical coupling between inner tiles is achieved by overlapping corresponding edge bus bars of adjacent strips. However, inter-tile electrical coupling within such a multi-tile module can be challenging. Strain relief connectors and long bus strips are used to facilitate inter-tile coupling. However, strain relief connectors can be expensive, and arranging the bus strips after laying out the cascaded strings can be tedious. To facilitate low-cost, high-volume manufacturing of solar roof tiles, in some embodiments, metal strips can be pre-laid on the back cover of the solar tile, forming embedded circuits that can be similar to metal traces on a printed circuit board (PCB). More specifically, the embedded circuits can be configured to facilitate electrical coupling between multiple solar roof tiles within a multi-tile module.

[0056] Furthermore, to facilitate electrical coupling between the embedded circuitry and the edge bus bars located on the front side of the cascade string, in some embodiments, a Si-based bridge electrode can be attached to the cascade string. The Si-based bridge electrode can include a metal layer covering its entire back side and, optionally, a trailing-edge bus bar. By overlapping its edge (e.g., the trailing-edge bus bar) with the leading-edge bus bar of the cascade string, the Si-based bridge electrode can transform itself into an electrode for the cascade string, converting the forward-facing electrode of the cascade string into an electrode accessible from the rear side of the cascade string.

[0057] 5A is a top view of an exemplary multi-tile module, according to one embodiment. Multi-tile module 500 can include PV roof tiles 502, 504, and 506 arranged side by side. Each PV roof tile can include six cascaded strips enclosed between a front cover and a back cover, meaning that the busbars located at either edge of a string of cascaded strips have opposite polarities. For example, if the left-most edge busbar of the strip in PV roof tile 502 has a positive polarity, the right-most edge busbar of the strip has a negative polarity. A series connection can be established between tiles by electrically coupling busbars with opposite polarities, while a parallel connection can be established between tiles by electrically coupling busbars with the same polarity.

[0058] In the example shown in FIG. 5A, the PV roof tiles are arranged so that their sun-facing sides have the same electrical polarity. As a result, edge busbars of the same polarity are on the same left or right edge. For example, the edge busbars on the left edge of all PV roof tiles can have a positive polarity and the edge busbars on the right edge of all PV roof tiles can have a negative polarity, or vice versa. In FIG. 6, the left edge busbars of all strips have a positive polarity (indicated by a "+" symbol) and are located on the sun-facing (or front) surface of the strip, while the right edge busbars of all strips have a negative polarity (indicated by a "-" symbol) and are located on the back surface. Depending on the design of the layer structure of the solar cell, the polarity and location of the edge busbars may differ from those shown in FIG. 5A.

[0059] Parallel connections between tiles can be formed by electrically coupling all left-most bus bars together via metal tab 510 and all right-most bus bars together via metal tab 512. Metal tabs 510 and 512, also known as connection buses, are typically used to interconnect individual solar cells or strings. The metal tabs can be stamped, cut, or otherwise formed from a conductive material such as copper. Copper is a highly conductive and relatively low-cost connector material. However, other conductive materials such as silver, gold, or aluminum can be used. In particular, silver or gold can be used as a coating material to prevent oxidation of the copper or aluminum. In some embodiments, an alloy heat-treated to have superelastic properties can be used for all or part of the metal tabs. Suitable alloys can include, for example, copper-zinc-aluminum (CuZnAl), copper-aluminum-nickel (CuAlNi), or copper-aluminum-beryllium (CuAlBe). Furthermore, the metal tab materials disclosed herein can be manipulated in whole or in part to modify their mechanical properties. For example, all or a portion of metal tabs 510 and 512 may be forged (eg, to increase strength), annealed (eg, to increase ductility), and / or tempered (eg, to increase surface hardness).

[0060] The coupling between the metal tabs and the busbars can be facilitated by specially designed strain relief connectors. In FIG. 5A, strain relief connector 516 can be used to couple busbar 514 to metal tab 510. Such strain relief connectors are required due to the mismatch in thermal expansion coefficients between metals (e.g., Cu) and silicon. As shown in FIG. 5A, metal tabs (e.g., tabs 510 and 512) can cross paths with strain relief connectors of opposite polarity. To prevent electrical shorting of the PV strip, portions of the metal tabs and / or strain relief connectors can be coated with an insulating film or wrapped with a sheet of insulating material.

[0061] In some embodiments, instead of connecting tiles in a tile module in parallel using stamped metal tabs and strain relief connectors as shown in FIG. 5A, a series connection between tiles can also be formed. FIG. 5B is a top view of an exemplary multi-tile module, according to one embodiment. Tile module 540 can include solar roof tiles 542, 544, and 546. Each tile can include multiple (e.g., six) cascaded photovoltaic strips arranged as shown in FIGS. 4A and 4B. Additionally, metal tabs can be used to interconnect PV strips enclosed in adjacent tiles. For example, metal tab 648 can connect the front of strip 632 with the rear of strip 630, forming a series connection between strips 630 and 632. While the example in FIG. 5B shows three metal tabs interconnecting the PV strips, other numbers of metal tabs can also be used. Additionally, each solar roof tile can include fewer or more cascaded strips, which can be of various shapes and sizes.

[0062] For simplicity of illustration, Figures 5A and 5B do not show inter-tile spacers that provide support and facilitate mechanical and electrical coupling between adjacent tiles. A detailed description of such inter-tile spacers can be found in U.S. Patent Application Publication No. 20190260328, entitled "INTER-TILE SUPPORT FOR SOLAR ROOF TILES," the disclosure of which is incorporated herein by reference in its entirety. Solar Roof Tile Color Matching

[0063] As shown in Figures 4C, 5A, and 5B, the PV structure and external electrodes encapsulated between the front and back covers can appear different from the background when viewed through the transparent, colorless front cover. More specifically, Si-based PV structures often appear to have a blue / purple hue. Applying color to the back cover can improve the color match between the PV structure and the background, but it cannot solve the problem of color angular dependence. In other words, the PV structure appears to have different colors at different viewing angles, which can make color matching difficult. Furthermore, apart from solar roof tiles, roofs may also contain a certain number of "passive" or "dead" roof tiles, i.e., roof tiles without embedded solar cells. These passive roof tiles may simply comprise a front and back cover and an encapsulant sandwiched between the covers. The difference in appearance between solar and passive roof tiles often results in a less appealing aesthetic.

[0064] FIG. 6 is a partial view of a roof with several solar and passive roof tiles. In FIG. 6, roof 600 can include multiple roof tiles arranged so that the bottom edges of tiles in an upper row overlap the top edges of tiles in a lower row, thus preventing water leakage. Furthermore, the tiles are offset so that the gaps between adjacent tiles in one row are somewhat aligned with the centers of tiles located in a different row. In the example shown in FIG. 6, tiles 602, 604, 606, and 608 are solar roof tiles and can include a PV structure encapsulated between a front cover and a back cover, while tiles 610 and 612 are passive roof tiles. As can be seen, the color contrast between the back cover and the PV structure can create the appearance of a "picture frame" for the solar roof tiles. In fact, the PV structure often appears to "float" above a colored back cover. Ideally, solar roof tiles 602 through 608 should have a similar appearance to passive roof tiles 610 and 612. The spacers 614 can fill gaps between adjacent tiles and prevent the passage of water between the PV tiles 602 to 608. In some embodiments, the spacers 614 can include electrical conductors that accommodate the passage of electricity and / or signals between adjacent PV tiles. In some embodiments, the spacers 614 can define channels through which wires or similar conductors can carry electricity and / or signals between adjacent PV tiles. roof tile base

[0065] The described embodiments include universal roof tile bases configured to support multiple different types of roof tiles, including photovoltaic (PV) roof tiles and non-PV roof tiles. A building's roof substrate can be covered with these universal roof tile bases, thereby alleviating the need for additional battens (e.g., horizontal strips of solid material) and / or individual legs to support the roof tiles on the roof substrate. Each of the roof tile bases may be identical, meaning that, except for minor manufacturing variations, the roof tile bases have the same size and share the same features and material properties. This prevents confusion due to using the wrong base for the wrong type of roof tile.

[0066] 7A and 7B are perspective views of the sun-facing and roof-facing surfaces of a roof tile base 700. The roof tile base can be formed using an injection molding process, which allows for the complex shapes shown to be mass-produced at a relatively low cost. Injection molding materials used to form the roof tile base can include, for example, polymeric and foam materials. The roof tile base 700 can also take the form of a sheet-formed part, a sheet-formed composite part, a stamped part, or a cast metal part. The roof tile base 700 is configured to support either a PV roof tile or a non-PV roof tile. FIG. 7A shows how the roof tile base 700 includes a flat sun-facing surface 702 configured to support a PV roof tile or a non-PV roof tile on a rooftop. The roof tile base 700 includes a plurality of apertures 704 configured to accommodate the passage of one or more tile hooks secured to the roof-facing surfaces of PV roof tiles supported by the roof tile base 700.

[0067] FIG. 7B illustrates how the roof tile base 700 also includes multiple vertical standoffs 706 that help establish the height and orientation of a PV or non-PV roof tile above the roof substrate. For example, the height of vertical standoff 706-1 as shown in FIG. 7B is less than the height of vertical standoff 706-2, which in turn is less than the height of vertical standoff 706-3. This allows the down-roof portion of a roof tile secured to the roof tile base 700 to be elevated slightly above the roof substrate relative to its up-roof end, thereby allowing the down-roof end of a first row of roof tiles to slightly overlap the up-roof end of a second row of roof tiles located directly below the first row of roof tiles. Compared to more traditional support structures that concentrate the weight of the roof tiles on the roof substrate, the multiple vertical standoffs allow for an even distribution of weight across the roof substrate, thereby allowing for larger roof tiles. Furthermore, it should be understood that the pattern and / or layout of the vertical standoffs can be arranged to suit a particular roof configuration. For example, the vertical standoffs can be arranged in a pattern that matches the roof assembly to which they are attached. This can help ensure that weight is transferred directly to the structural framing members of the roof, thereby reducing loads on sheathing that extends across gaps between structural assembly members and allowing fasteners to engage directly with the solid wood of the assembly members instead of plywood, which is commonly used as sheathing, thereby making the roof less susceptible to high wind conditions. In some embodiments, spacing the vertical standoffs in this manner can facilitate direct attachment of roof tile bases to the structural assembly members of the roof without the need for a traditional roof substrate formed from roof girders or roof sheathing. In such a configuration, the structural assembly members constitute the roof substrate. Matching the vertical standoff members in this manner can result in irregular spacing between the vertical standoffs to accommodate roofs that accommodate specific structural assembly member spacing.

[0068] 7A also shows how the standoffs 706 define recesses 708, which help reduce the overall weight of the roof tile base 700 and, in cooperation with the cable channels 710, allow for the routing of cabling between the PV roof tiles and the roof tile base 700. The roof tile base also defines a plurality of apertures 712, which allow for the passage of any cabling associated with the PV roof tiles therethrough, thus allowing the cabling to be routed between the roof tile base 700 and the roof substrate. Exit channels 714 allow any cabling routed through the recesses 708 and the cable channels 110 to exit the respective cable channels 110 and pass through the apertures 712 for routing underneath the roof tile base 700. The roof tile base 700 also includes side standoffs 716, which help to position the roof tile base 700 relative to the roof tile base located one row below it. The lateral standoffs 716 are positioned below the sun-facing surface 702 and slightly behind the leading edge 718 of the roof tile base 700, thereby allowing the leading edge 718 to overlap the uproof portion of the roof tile base adjacent to the roof tile base 700.

[0069] Roof tile base 700 further includes a plurality of non-PV tile retention features, including retention features 720 and 722. Retention features 720 and 722 are configured to prevent movement of the non-PV tiles relative to roof tile base 700, and their functions are described in more detail below. Roof tile base 700 also defines an electrical recess 724 for accommodating electrical inputs / outputs disposed on the roof-facing surface of the PV roof tile. In some embodiments, electrical recess 724 can accommodate a junction box configured to protect electrical wires entering and exiting the PV roof tile. FIGS. 7A-7B also show how the uproof-facing edge of roof tile base 700 includes alignment notches 726 configured to receive lateral standoffs 716 from the roof tile base of the uproof. The shape and size of alignment notch 726 have a shape and size that matches the distal ends of lateral standoffs 716, helping to achieve a consistent horizontal offset between the roof tile bases of adjacent rows of roof tile bases.

[0070] FIG. 7C illustrates the engagement of the lateral standoffs 716 within the alignment notches 726. FIG. 7C also illustrates how the forward or leading edge of the downroof-facing portion of the roof tile base 700-1 overlaps the uproof-facing portion of the roof tile base 700-2 when the lateral standoffs 716 are engaged within the alignment notches 726. FIG. 7C also illustrates how the lateral edges of the roof tile base 700-1 align with the central region of the roof tile base 700-2 when the lateral standoffs 716 engage with the alignment notches 726, resulting in a half-tile offset between adjacent rows of roof tiles. In some embodiments, the roof tile base can include more alignment notches 726, allowing for more horizontal offset options to accommodate customer preferences. FIG. 7C also illustrates how the roof tile base 700 can be secured to any roof substrate using one or more fasteners 728 driven through the vertical standoffs 706. In some embodiments, the vertical standoffs 706 can include fastener openings that make it easier to attach the roof tile base 700 to the roof substrate 730 .

[0071] Figure 7D is a cross-sectional view of roof tile bases 700-1 and 700-2 through section line AA in Figure 7C. Specifically, Figure 7D shows how lateral standoffs 716 abut with alignment notches 726 to establish a predetermined amount of overlap of roof tile base 700-1 over roof tile base 700-2. In some embodiments, distal ends 717 of lateral standoffs 716 can be vertically flared, as shown, to avoid alignment issues when undulations or irregularities in the surface of the roof substrate result in changes in the vertical position of each roof tile base. Figure 7D also shows how the vertical standoffs can include drainage channels that allow moisture collected within the recesses defined by each vertical standoff to flow away from the vertical standoff.

[0072] Figure 7E is a perspective view of a corner of laterally adjacent roof tile bases 700-1 and 700-3. In particular, retention features 722-1 and 722-2 are closely spaced and separated by a gap 734 having a width that allows sufficient clearance for PV and / or non-PV roof tiles to be placed on top of roof tile bases 700-1 and 700-2. Figure 7E also shows that roof tile base 700-1 can include an integral side wrap 736 that extends below gap 734 to direct moisture passing through the downroof between roof tile bases 700-1 and 700-3 and prevent the moisture from collecting on roof substrate 730.

[0073] 7F is a cross-sectional view of roof tile bases 700-1 and 700-3 through section line BB. In particular, integral side laps 736 are shown extending below gaps 734. As shown, integral side laps 736 define channels 738 that help guide moisture passing through gaps 734 downroof and evacuate onto the downroof of PV or non-PV roof tiles from roof tile bases 700-1 and 700-3. As shown, integral side laps 736 are sized to also function as lateral standoffs by engaging the walls of vertical standoffs 706.

[0074] FIG. 8A shows a perspective view of a PV roof tile 800. In particular, the roof-facing surface 802 of the PV roof tile 800 is shown. FIG. 8 shows six tile hooks 804 attached to the roof-facing surface 802 of the PV roof tile 800. The tile hooks 804 are configured to extend through apertures 704 in the roof tile base 700 to attach the PV roof tile 800 to the PV roof tile base 700. While the PV roof tile 800 includes six tile hooks 804, it should be understood that the roof tile 800 can include a fewer number of tile hooks 804, such as four, or a greater number of tile hooks 804, such as eight or ten tile hooks 804, depending on the desired size of the PV roof tile 800. Generally, the number of tile hooks 804 scales with the size of the roof tile 800. In some embodiments, the roof tile base 700 can have four tile hooks 804 and still be compatible with the roof tile base 700 as shown in FIGS. 7A to 7F . For example, the center two of the tile hooks 804 can be removed, and the tile hooks 804 can still be configured to engage the edges of the peripheral apertures 704 of the roof tile base 700. If the spacing of the vertical standoffs 706 varies to accommodate a particular roof construction, the positions of the tile hooks 804 can be shifted to account for the change in the position of the vertical standoffs 706 and the apertures 704 between the vertical standoffs 706 that receive the tile hooks 804.

[0075] FIG. 8A also shows how a junction box 806 may be attached to the roof-facing surface 802 of the PV roof tile 800. The junction box 806 may be configured to help electrically couple cables 808-1 and 808-2 to the power-generating solar cells contained within the PV roof tile 800. Each of the cables 808 may include a female plug 810 or a male plug 812 for electrically coupling the PV roof tile 800 to adjacent PV roof tiles and / or other electrical components. While the interior of the PV roof tile 800 is not shown in FIG. 8A , the PV roof tile 800 may be configured in a variety of ways, as described in FIGS. 2-6 . As depicted in FIGS. 2-6 , the PV roof tile 800 includes a back cover including the roof-facing surface 802, a front cover including a sun-facing surface, and a plurality of solar cells disposed between the front and back covers.

[0076] 8B shows a perspective view of a PV roof tile 800 positioned on a roof tile base 700. The tile hooks 804 are shown extending through each aperture 704, such that the tile hooks 804 are aligned with recesses 814 in the portions of the roof tile base 700 that define each aperture 704. The recesses 814 have a width that matches (i.e., is the same as or slightly larger than) the width of the tile hooks 804, such that the recesses 814 can help achieve horizontal alignment between the PV roof tile 800 and the roof tile base 700. In addition to providing a way to route one or more cables out of the area between the PV roof tile 800 and the roof tile base 700, the exit channel 714 also prevents an installer from attaching the tile hook 804 to the edge of one of the apertures 712 because the tile hook 804 would be insufficiently tall to slide over the exit channel 714.

[0077] Figure 8C shows the PV roof tile 800 fully engaged with the roof tile base 700. This engagement can be confirmed by observing that the PV roof tile 800 is aligned with the roof tile base 700 and that each of the tile hooks 804 is engaged with the edge of one of the apertures 704. Figure 8C also shows how the junction box 806 fits within and is housed by the electrical component recess 724. The shape of the electrical component recess 724 is formed to allow the cables 808 to extend from either side of the junction box 806 and then gradually bend to exit the electrical component recess 724.

[0078] 9A illustrates a non-PV roof tile 900 and how it is configured to slide onto roof tile base 700. In some embodiments, the non-PV roof tile 900 may be formed of sheet metal, and the sun-facing surface 902 of the non-PV roof tile 900 may be finished to have an appearance that matches the sun-facing surface of the PV roof tile 800, which is typically formed of glass or an optically transparent polymeric material. In some embodiments, the non-PV roof tile 900 includes a plurality of flaps 904 arranged to align with the retention features 720. As shown, the retention features 720 are embodied as rectangular apertures arranged along the uproof-facing edge of the roof tile base 700. The flaps 904 are formed by cutting U-shaped slots in the sheet metal substrate of the sun-facing surface 902 of the non-PV roof tile 900, as shown. Once the non-PV roof tile 900 has been slid completely over the roof tile base 700, the installer can bend the flap 904 downward by 5 to 10 degrees to engage the side walls defining each of the retention features 720. In this manner, downward forces applied to the non-PV roof tile 900 can be resisted by the engagement of the distal end of the flap 904 with the side walls of the retention features 720. It should be noted that while the downward deflection of the flap 904 provides a potential ingress path for moisture, due to the location of the flap 904 at the up-roof end of the non-PV roof tile 900, the up-roof roof tile will generally overlap this portion of the non-PV roof tile, thereby reducing the likelihood of moisture entering through small openings caused by the deflection of the flap 904.

[0079] 9A also includes a close-up view 906 showing retention features 722 of roof tile base 700 and notches 908 included in the sidewalls of non-PV roof tile 900. Retention features 722 take the form of tabs having wedge-shaped heads 740 configured to flex inward upon engaging sidewall segments 910 of non-PV roof tile 900 as non-PV roof tile 900 is being slid in installation direction 912. Notches 908 allow wedge-shaped heads 740 of retention features 722 to enter notches 908, thereby returning to their initial position once non-PV roof tile 900 fully covers roof tile base 700.

[0080] 9B shows the non-PV roof tile 900 fully engaged with the roof tile base. In particular, close-up view 914 shows how the wedge-shaped head 740 of the roof tile base 700 occupies the notch 908 of the non-PV roof tile 900. Furthermore, when the wedge-shaped head 740 engages within the notch 908, the surface of the wedge-shaped head 740 facing the uproof can be configured to prevent the sidewall segment 910 from moving downroof, thereby providing an additional method of securing the non-PV roof tile 900 to the roof tile base 700. A roof technician can also disengage the non-PV roof tile 900 from the roof tile base 700 by pushing the wedge-shaped head 740 to disengage the sidewall segment 910 from the wedge-shaped head 740, allowing the PV roof tile to slide down the roof and off of the roof tile base 700. It should be understood that the non-PV roof tile base can include numerous retention features, including those described herein. For example, instead of engaging the retention feature 720 with the flap 904, the non-PV roof tile 900 may include fastener openings that allow an installer to drive one or more fasteners through the non-PV roof tile 900 and into the roof tile base 700.

[0081] 9B also includes a close-up view 916 showing the shape of the sidewalls of the non-PV roof tile 900 and how the sidewalls 918 at least partially wrap under the sides of the roof tile base 700. While only a small extension of the sidewalls 918 is shown, it should be understood that the sidewalls 918 can further wrap under the roof tile base 700 to reduce the likelihood of the sidewalls 918 becoming unintentionally detached from the roof tile base 700.

[0082] 10A through 10E illustrate an exemplary process for installing roof tiles on multiple roof tile bases of a house 1000. In particular, FIG. 10A illustrates how multiple roof tile bases 700 can be secured to a roof substrate 1002. One or more fasteners are typically used to secure at least this first row of roof tile bases to the roof substrate 1002. FIG. 10B illustrates how this first row of roof tile bases 700 can then be covered by non-PV roof tiles 900. Installation of the non-PV roof tiles 900 involves sliding the non-PV roof tiles 900 up the roof and over each roof tile base 700 until the retention features of the roof tile base 700 engage the sidewalls of the non-PV roof tiles 900. In embodiments in which the non-PV roof tile 900 includes a flap for engaging a retaining feature in the roof tile base 700, the installer can also bend the flap into an aperture defined by the roof tile base 700 to further prevent inadvertent movement of the non-PV roof tile 900 relative to the roof tile base 700.

[0083] FIG. 10C illustrates the installation of a second row of roof tile bases 700. Notably, roof tile base 1004 is not shown as having the same overall width as roof tile base 700. Because roof tile base 700 is formed of a polymeric or other material that allows it to be cut straight to the desired shape, a roofing contractor can cut and shape the roof tile base so that it can fit any portion of the roof substrate. While roof tile base 1004 is shown simply narrow, more complex shape variations are possible. For example, circular or rectangular holes can be punched into the roof tile base to accommodate the passage of air vents. Non-PV roof tiles formed from sheet metal can also be reshaped in this manner. For example, FIG. 10D illustrates how a portion of non-PV roof tile 1006 can overlap roof tile base 1004. In this way, portions of roof substrate 1002 that would otherwise not fit into a regular-sized roof tile can be covered with roof tiles that have the same look and feel as the other roof tiles, except for their size. Figure 10D also shows how PV roof tiles 800 can be lowered into a second row of roof tile bases, thereby showing PV roof tiles mixed with non-PV roof tiles. Figure 10E shows a third row of roof tile bases 700 added on top of, and slightly overlapping, the PV roof tiles 800. The third row of roof tile bases 700 can contain PV roof tiles or non-PV roof tiles, or a mixture of both, as roof tile bases 700 are equally suitable to accommodate PV roof tiles and non-PV roof tiles.

[0084] 11A through 11F illustrate how the height of various portions of the roof tile base varies. FIG. 11A shows a top view of the roof tile base 1100 with section line CC intersecting the down-roof edge of the roof tile base 1100 and section line DD intersecting the up-roof edge of the roof tile base 1100. In particular, as previously discussed, the down-roof edge of the roof tile base 1100 shown in FIG. 11B extends further above the roof substrate 1102 than the up-roof edge of the roof tile base 1100 shown in FIG. 11C, allowing the down-roof edge to overlap the up-roof edge of a roof tile positioned one row below the roof tile base 1100. The angle of the sun-facing surface of the roof tile base 1100 from the up-roof edge to the down-roof edge can be between approximately 0.5 degrees and 2 degrees. The illustrated embodiment shown herein is based on a 1-degree angle.

[0085] FIG. 11D shows a top view of the roof tile base 1110 with section line EE taken across the down-roof end of the roof tile base 1110 and section line FF taken across the up-roof end of the roof tile base 1110. In particular, the cross-sectional views shown in FIGS. 11E and 11F illustrate how each corner region of the roof tile base 1110 can be at a different height above the roof substrate 1112. This variation in height results from the roof tile base 1110 varying the height of its sun-facing surface above the roof substrate 1112 from left to right and from the up-roof end to the down-roof end. In some embodiments, tilting the roof tiles from left to right reduces the appearance of inconsistencies due to unevenness in the roof substrate. The variation in height from the first side of the roof tile base to the second side of the roof tile base can be achieved by setting an angle between 1 and 3 degrees.

[0086] The foregoing description of various embodiments has been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the system to the precise form disclosed. Accordingly, many modifications and variations will be apparent to those skilled in the art. Also, the above disclosure is not intended to limit the system.

Claims

1. 1. A photovoltaic (PV) roof tile, comprising: Optically transparent front cover, Back cover, a plurality of solar cells disposed between the optically transparent front cover and the back cover; and a photovoltaic (PV) roof tile comprising a plurality of tile hooks coupled to said back cover; A roof tile base, said roof tile base comprising: a sun-facing surface in direct contact with the back cover and extending from a first side of the roof tile to a second side of the roof tile opposite the first side; a plurality of vertical standoffs configured to establish the height of the sun-facing surface above a roof substrate; and a roof tile base comprising a plurality of apertures extending through the roof tile base, wherein a first tile hook of the plurality of tile hooks extends through a first aperture of the plurality of apertures and engages a portion of the roof tile base defining the first aperture; A roof tile assembly comprising:

2. 10. The roof tile assembly of claim 1, wherein the roof tile base comprises a plurality of lateral standoffs projecting from a downroof-facing end of the roof tile base below the sun-facing surface of the roof tile base.

3. 3. The roof tile assembly of claim 1 or 2, wherein the roof tile base further comprises a plurality of alignment notches extending into the sun-facing surface of the roof tile base.

4. 4. The roof tile assembly of claim 1, wherein the plurality of alignment notches are configured to receive lateral standoffs of the roof tile base of another roof tile base uproof.

5. The roof tile assembly of claim 1 , wherein the plurality of vertical standoffs comprises four or more vertical standoffs.

6. 6. The roof tile assembly of claim 1, wherein the roof tile base is a single injection molded part.

7. The roof tile assembly of claim 6 wherein the roof tile base is formed from a polymeric material.

8. 8. The roof tile assembly of claim 1, wherein the PV roof tile comprises a junction box coupled to the back cover, and the roof tile base defines an electrical component recess to accommodate the height of the junction box between the roof tile base and the back cover.

9. 9. The roof tile assembly of claim 1, wherein the roof tile base includes a plurality of retention features configured to attach the roof tile base to a non-PV roof tile.

10. 10. The roof tile assembly of claim 1, wherein a first vertical standoff of the plurality of vertical standoffs is larger than a second vertical standoff of the plurality of vertical standoffs.

11. 11. The roof tile assembly of claim 1, wherein bottom surfaces of the plurality of vertical standoffs cooperate to define a first plane that is anti-parallel to the sun-facing surface.

12. 12. The roof tile assembly of claim 1, wherein the roof tile base is configured to position a first corner region of the sun-facing surface a first distance from the roof substrate, a second corner region of the sun-facing surface a second distance from the roof substrate, a third corner region of the sun-facing surface a third distance from the roof substrate, and a fourth corner region of the sun-facing surface a fourth distance from the roof substrate.

13. 13. The roof tile assembly of claim 12, wherein the first distance is greater than the second distance, the second distance is greater than the third distance, and the third distance is greater than the fourth distance.

14. 14. The roof tile assembly of claim 1, wherein the roof tile base further comprises an integral side lap configured to protrude from a side of the roof tile base and extend below a gap between the roof tile base and another roof tile base adjacent to the roof tile base.

15. 1. A photovoltaic (PV) roof tile, the photovoltaic (PV) roof tile comprising a sheet metal substrate, the sheet metal substrate comprising: a flat central region, a first sidewall at a first end of the flat central region and defining a first notch; and a non-photovoltaic (non-PV) roof tile having a second sidewall at a second end of the flat central region opposite the first end, the second sidewall defining a second notch; A roof tile base, a sun-facing surface in direct contact with the flat central region and extending from the first sidewall to the second sidewall; a plurality of vertical standoffs configured to establish the height of said sun-facing surface above a roof substrate; a first retention feature on a first side of the roof tile base engaged within the first notch of the first sidewall; and a roof tile base including a second retention feature on a second side of the roof tile base engaged within the second notch of the second side wall; A roof tile assembly comprising:

16. 16. The roof tile assembly of claim 15, wherein the roof tile base comprises a plurality of lateral standoffs projecting from a downroof-facing end of the roof tile base below the sun-facing surface of the roof tile base.

17. 17. The roof tile assembly of claim 16, wherein the roof tile base further comprises a plurality of alignment notches extending into the sun-facing surface of the roof tile base.

18. 18. The roof tile assembly of claim 17, wherein the plurality of alignment notches are configured to receive lateral standoffs of the roof tile base of another roof tile base uproof.

19. 19. The roof tile assembly of any one of claims 15 to 18, wherein the plurality of vertical standoffs comprises four or more vertical standoffs.

20. 20. A roof tile assembly according to any one of claims 15 to 19, wherein the roof tile base is a single injection moulded part.

21. 21. The roof tile assembly of claim 20, wherein the roof tile base is formed from a polymeric material.

22. 22. The roof tile assembly of any one of claims 15 to 21, wherein a first vertical standoff of the plurality of vertical standoffs is larger than a second vertical standoff of the plurality of vertical standoffs.

23. 23. The roof tile assembly of any one of claims 15 to 22, wherein bottom surfaces of the plurality of vertical standoffs cooperate to define a first plane that is anti-parallel to the sun-facing surface.

24. 24. The roof tile assembly of any one of claims 15 to 23, wherein the roof tile base is configured to position a first corner region of the sun-facing surface a first distance from the roof substrate, a second corner region of the sun-facing surface a second distance from the roof substrate, a third corner region of the sun-facing surface a third distance from the roof substrate, and a fourth corner region of the sun-facing surface a fourth distance from the roof substrate.

25. 25. The roof tile assembly of claim 24, wherein the first distance is greater than the second distance, the second distance is greater than the third distance, and the third distance is greater than the fourth distance.

26. 26. The roof tile assembly of any one of claims 15 to 25, wherein the non-PV roof tile comprises a plurality of flaps, the plurality of flaps engaging within respective retention features of a plurality of retention features of the roof tile base.

27. 27. The roof tile assembly of claim 26, wherein the plurality of retention features comprises a plurality of apertures extending through an uproof portion of the roof tile base.

28. A roof, the roof comprising: A first roof tile assembly, said first roof tile assembly comprising: a first roof tile base; and a photovoltaic (PV) roof tile disposed on the first roof tile base. a first roof tile assembly comprising: a second roof tile assembly adjacent to the first roof tile assembly, the second roof tile assembly comprising: a second roof tile base; and a second roof tile assembly comprising a non-photovoltaic (non-PV) roof tile disposed on the second roof tile base; A roof, wherein the first roof tile base is the same as the second roof tile base.

29. The PV roof tile is An optically transparent front cover; Back cover and a plurality of solar cells disposed between the optically transparent front cover and the back cover; 30. The roof of claim 28, comprising: a plurality of tile hooks coupled to the back cover.

30. the first roof tile base comprising: a sun-facing surface in direct contact with the back cover and extending from a first side of the roof tile to a second side of the roof tile opposite the first side; a plurality of vertical standoffs configured to establish the height of the sun-facing surface above a roof substrate; 30. The roof of claim 29, comprising a plurality of apertures extending through the first roof tile base, wherein a first tile hook of the plurality of tile hooks extends through a first aperture of the plurality of apertures and engages a portion of the first roof tile base defining the first aperture.

31. 31. The roof of claim 30, wherein the first roof tile base is configured to position a first corner region of the sun-facing surface a first distance from the roof substrate, a second corner region of the sun-facing surface a second distance from the roof substrate, a third corner region of the sun-facing surface a third distance from the roof substrate, and a fourth corner region of the sun-facing surface a fourth distance from the roof substrate.

32. 32. The roof of claim 31, wherein the first distance is greater than the second distance, the second distance is greater than the third distance, and the third distance is greater than the fourth distance.

33. The non-PV roof tile is a flat central region; a first sidewall at a first end of the flat central region and defining a first notch; a second sidewall at a second end of the flat central region opposite the first end, the second sidewall defining a second notch; 33. The roof of any one of claims 28 to 32, comprising:

34. the second roof tile base: a sun-facing surface in direct contact with the flat central region and extending from the first sidewall to the second sidewall; a plurality of vertical standoffs configured to establish the height of the sun-facing surface above a roof substrate; a first retention feature on a first side of the second roof tile base engaged within the first notch of the first sidewall; a second retention feature on a second side of said second roof tile base engaged within said second notch of said second sidewall.

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